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IEEE Projects on:Java & .NET

Mobile Application Projects on:J2ME & ANDROID

IEEE Projects on:Java & .NET

Mobile Application Projects on:J2ME & ANDROID

.NET IEEE

.NET Network Security Abstracts

Integration Of Sound Signature In Graphical Password Authentication (2011)

ABSTRACT
Passwords are used for – (a) Authentication (Establishes that the user is who they say they are). (b) Authorization (The process used to decide if the authenticated person is allowed to access specific information or functions) and(c) Access Control (Restriction of access-includes authentication & authorization).Mostly user select password that is predictable. This happens with both graphical and text based passwords. Users tend to choose memorable password, unfortunately it means that the passwords tend to follow predictable patterns that are easier for attackers to guess. While the predictability problem can be solved by disallowing user choice and assigning passwords to users, this usually leads to usability issues since users cannot easily remember such random passwords. Number of graphical password systems has been developed; Study shows that text-based passwords suffer with both security and usability problems. According to a recent news article, a security team at a company ran a network password cracker and within 30 seconds and they identified about 80% of the passwords. It is well know that the human brain is better at recognizing and recalling images than text, graphical passwords exploit this human characteristic. The password is a very common and widely authentication method still used up to now but because of the huge advance in the uses of computer in many applications as data transfer, sharing data, login to emails or internet, some drawbacks of normal password appear like stolen the password, forgetting the password, week password, etc so a big necessity to have a strong authentication way is needed to secure all our applications as possible, so researches come out with advanced password called graphical password where they tried to improve the password techniques and avoid the weakness of normal password. Alphanumeric passwords were first introduced in the late 1960s.Today, many networks, computer systems and Internet-based environments used this technique to authenticate their users. The vulnerabilities of this technique have been well known generally. Dictionary attack is the commonly method used by hackers to break or crack the alphanumeric password, such attack is very efficient mechanism because its only need a little time to discover the users passwords. Another major drawback of this method is the difficulty of remembering the passwords. As studied by Gilhooly, the good and hard to guess or break passwords basically difficult to memorize. Recent studies from Dhamija et al (2000) showed that humans are only capable to memorize a limited number of passwords, because of this syndrome, they often to write down, share and use the same passwords for different current account. Graphical password techniques have been proposed as an alternative to alphanumeric based techniques. It has been designed to overcome the known weakness of traditional alphanumeric password. It also designed to make the passwords more memorable, easier for people to use and therefore more secure. Based on the two assumptions; first, humans can remember pictures better than alphanumeric characters and second, a picture worth a thousand passwords; some psychological studies and company software seem to agree with these assumptions. As known generally, the main drawbacks for the current graphical password schemes are the shoulder surfing problem and usability problem. Even though graphical passwords are difficult to guess and break, Nevertheless, the issue of how to design the authentication systems which have both the security and usability elements is yet another example of what making the challenge of Human Computer Interaction (HCI) and security communities.

NABS: Novel Approaches for Biometric Systems (2011)

ABSTRACT
Research on biometrics has noticeably increased. However, no single bodily or behavioral feature is able to satisfy acceptability, speed, and reliability constraints of authentication in real applications. The present trend is therefore toward multimodal systems. In this paper, we deal with some core issues related to the design of these systems and propose a novel modular framework, namely, novel approaches for biometric systems (NABS) that we have implemented to address them. NABS proposal encompasses two possible architectures based on the comparative speeds of the involved biometries. It also provides a novel solution for the data normalization problem, with the new quasi-linear sigmoid (QLS) normalization function. This function can overcome a number of common limitations, according to the presented experimental comparisons. A further contribution is the system response reliability (SRR) index to measure response confidence. Its theoretical definition allows taking into account the gallery composition at hand in assigning a system reliability measure on a single-response basis. The unified experimental setting aims at evaluating such aspects both separately and together, using face, ear, and fingerprint as test biometries. The results provide a positive feedback for the overall theoretical framework developed herein. Since NABS is designed to allow both a flexible choice of the adopted architecture, and a variable compositions and/or substitution of its optional modules, i.e., QLS and SRR, it can support different operational settings.

A More Secure Steganography Method in Spatial Domain (2011)

ABSTRACT
This paper presents a new approach for hiding message in digital image in spatial domain. In this method two bits of message is embedded in a pixel in a way that not only the least significant bit of pixel is allowed to change but also the second bit plane and fourth bit plane are allowed to be manipulated, But the point is in each embedding process only one alternation in one bit plane is allowed to happen. As it is compared by the method LSB-Matching, the results shows this method has an acceptable capacity of embedding data and hardly is detectable for steganalysis algorithm

Signature-free buffer overflow attack blocker (2010)

ABSTRACT
This project propose SigFree, a real time, signature-free, out-of the-box, application layer blocker for preventing buffer overflow attacks, one of the most serious cyber security threats. SigFree can filter out code-injection buffer overflow attack messages targeting at various Internet services such as web service. Motivated by the observation that buffer overflow attacks typically contain executables whereas legitimate client requests never contain executables in most Internet services, SigFree blocks attacks by detecting the presence of code. SigFree first blindly dissembles and extracts instruction sequences from a request. It then applies a novel technique called code abstraction, which uses flow anomaly to prune useless instructions in an instruction sequence. Finally it compares the number of useful instructions to a threshold to determine if this instruction sequence contains code. SigFree is signature free, thus it can block new and unknown buffer overflow attacks; SigFree is also immunized from most attack-side code obfuscation methods. Since SigFree is transparent to the servers being protected, it is good for economical Internet wide deployment with very low deployment and maintenance cost. We implemented and tested SigFree; our experimental study showed that SigFree could block all types of code injection attack packets (above 250) tested in our experiments. Moreover, SigFree causes negligible throughput degradation to normal client requests

The Effectiveness of Checksums for Embedded Control Networks (2009)

ABSTRACT
Embedded control networks commonly use checksums to detect data transmission errors. However, design decisions about which checksum to use are difficult because of a lack of information about the relative effectiveness of available options. We study the error detection effectiveness of the following commonly used checksum computations: exclusive or (XOR), two's complement addition, one's complement addition, Fletcher checksum, Adler checksum, and cyclic redundancy codes (CRCs). A study of error detection capabilities for random independent bit errors and burst errors reveals that the XOR, two's complement addition, and Adler checksums are suboptimal for typical network use. Instead, one's complement addition should be used for networks willing to sacrifice error detection effectiveness to reduce computational cost, the Fletcher checksum should be used for networks looking for a balance between error detection and computational cost, and CRCs should be used for networks willing to pay a higher computational cost for significantly improved error detection.

Performance of Orthogonal Fingerprinting Codes under Worst-Case Noise (2009)

ABSTRACT
We study the effect of the noise distribution on the error probability of the detection test when a class of randomly rotated spherical fingerprints is used. The detection test is performed by a focused correlation detector, and the spherical codes studied here form a randomized orthogonal constellation. The colluders create a noise-free forgery by uniform averaging of their individual copies, and then add a noise sequence to form the actual forgery. We derive the noise distribution that maximizes the error probability of the detector under average and almost-sure distortion constraints. Moreover, we characterize the noise distribution that minimizes the decoder's error exponent under a large-deviations distortion constraint

Spread-Spectrum Watermarking Security (2009)

ABSTRACT
This paper presents both theoretical and practical analyses of the security offered by watermarking and data hiding methods based on spread spectrum. In this context, security is understood as the difficulty of estimating the secret parameters of the embedding function based on the observation of watermarked signals. On the theoretical side, the security is quantified from an information-theoretic point of view by means of the equivocation about the secret parameters. The main results reveal fundamental limits and bounds on security and provide insight into other properties, such as the impact of the embedding parameters, and the tradeoff between robustness and security. On the practical side, workable estimators of the secret parameters are proposed and theoretically analyzed for a variety of scenarios, providing a comparison with previous approaches, and showing that the security of many schemes used in practice can be fairly low.

A New Model For Dissemination Of Xml (2008)

ABSTRACT
The paper proposes an approach to content dissemination that exploits the structural properties of an Extensible Markup Language (XML) document object model in order to provide an efficient dissemination and at the same time assuring content integrity and confidentiality. Our approach is based on the notion of encrypted post order numbers that support the integrity and confidentiality requirements of XML content as well as facilitate efficient identification, extraction, and distribution of selected content portions. By using such notion, we develop a structure based routing scheme that prevents information leaks in the XML data dissemination, and assures that content is delivered to users according to the access control policies, that is, policies specifying which users can receive which portions of the contents. Our proposed dissemination approach further enhances such structure based, policy-based routing by combining it with multicast in order to achieve high efficiency in terms of bandwidth usage and speed of data delivery, thereby enhancing scalability. Our dissemination approach thus represents an efficient and secure mechanism for uses in applications such as publish–subscribe systems for XML Documents. The publish–subscribe model restricts the consumer and document source information to the routers to which they register with. Our framework facilitates dissemination of contents with varying degrees of confidentiality and integrity requirements in a mix of trusted and un-trusted networks, which is prevalent in current settings across enterprise networks and the web. Also, it does not require the routers to be aware of any security policy in the sense that the routers do not need to implement any policy related to access control.

Credit Card Fraud Detection Using Hidden Markov Models (2008)

ABSTRACT
Due to a rapid advancement in the electronic commerce technology, the use of credit cards has dramatically increased. As credit card becomes the most popular mode of payment for both online as well as regular purchase, cases of fraud associated with it are also rising. In this paper, we model the sequence of operations in credit card transaction processing using a Hidden Markov Model (HMM) and show how it can be used for the detection of frauds. An HMM is initially trained with the normal behavior of a cardholder. If an incoming credit card transaction is not accepted by the trained HMM with sufficiently high probability, it is considered to be fraudulent. At the same time, we try to ensure that genuine transactions are not rejected. We present detailed experimental results to show the effectiveness of our approach and compare it with other techniques available in the literature.

An Efficient Time-Bound Hierarchical Key Management Scheme for Secure Broadcasting (2008)

ABSTRACT
In electronic subscription and pay TV systems, data can be organized and encrypted using symmetric key algorithms according to predefined time periods and user privileges and then broadcast to users. This requires an efficient way of managing the encryption keys. In this scenario, time-bound key management schemes for a hierarchy were proposed. Both schemes are insecure against collusion attacks. In this paper, we propose a new key assignment scheme for access control, which is both efficient and secure. Elliptic-curve cryptography is deployed in this scheme. We also provide the analysis of the scheme with respect to security and efficiency issues.

Temporal Portioning of Communication Resources in an Integrated Architecture (2008)

ABSTRACT
Integrated architectures in the automotive and avionic domain promise improved resource utilization and enable a better coordination of application subsystems compared to federated systems. An integrated architecture shares the system's communication resources by using a single physical network for exchanging messages of multiple application subsystems. Similarly, the computational resources (for example, memory and CPU time) of each node computer are available to multiple software components. In order to support seamless system integration without unintended side effects in such an integrated architecture, it is important to ensure that the software components do not interfere through the use of these shared resources. For this reason, the DECOS integrated architecture encapsulates application subsystems and their constituting software components. At the level of the communication system, virtual networks on top of an underlying time-triggered physical network exhibit predefined temporal properties (that is, bandwidth, latency, and latency jitter). Due to encapsulation, the temporal properties of messages sent by a software component are independent from the behavior of other software components, in particular from those within other application subsystems. This paper presents the mechanisms for the temporal partitioning of communication resources in the Dependable Embedded Components and Systems (DECOS) integrated architecture. Furthermore, experimental evidence is provided in order to demonstrate that the messages sent by one software component do not affect the temporal properties of messages exchanged by other software components. Rigid temporal partitioning is achievable while at the same time meeting the performance requirements imposed by present-day automotive applications and those envisioned for the future (for example, X-by-wire). For this purpose, we use an experimental framework with an implementation of virtual networks on top of a Time Division Multiple Access (TDMA)-controlled Ethernet network.

Trustworthy Computing Under Resource Constraints With The Down Policy (2008)

ABSTRACT
Trustworthy computing modules like secure coprocessors (ScP) are already in extensive use today, albeit limited predominantly to scenarios where constraints on cost are not a serious limiting factor. However, inexpensive trustworthy computers are required for many evolving application scenarios. The problem of realizing inexpensive ScPs for large-scale networks consisting of low complexity devices have not received adequate consideration thus far. We introduce two strategies toward realizing low-cost ScPs. The first is the decrypt only when necessary (DOWN) policy, which can substantially improve the ability of low-cost ScPs to protect their secrets. The DOWN policy relies on the ability to operate with fractional parts of secrets. Taking full advantage of the DOWN policy requires consideration of the nature of computations performed with secrets and even the mechanisms employed for distribution of secrets. We discuss the feasibility of extending the DOWN policy to various asymmetric and symmetric cryptographic primitives. The second is cryptographic authentication strategies which employ only symmetric cryptographic primitives, based on novel ID-based key predistribution schemes that demand very low complexity of operations to be performed by the ScP and can take good advantage of the DOWN policy.

Fuzzy Control Model Optimization for Behavior-Constant Traffic Routing Under Information Provision (2008)

ABSTRACT
This paper presents an H-infinity filtering approach to optimize a fuzzy control model used to determine behavior consistent (BC) information-based control strategies to improve the performance of congested dynamic traffic networks. By adjusting the associated membership function parameters to better respond to nonlinearities and modeling errors, the approach is able to enhance the computational performance of the fuzzy control model. Computational efficiency is an important aspect in this problem context, because the information strategies are required in sub real time to be real-time deployable. Experiments are performed to evaluate the effectiveness of the approach. The results indicate that the optimized fuzzy control model contributes in determining the BC information-based control strategies in significantly less computational time than when the default controller is used. Hence, the proposed H-infinity approach contributes to the development of an efficient and robust information-based control approach.

Morphological Granulometric Features of Nucleus in Automatic Bone Marrow White Blood Cell Classification (2007)

ABSTRACT
The proportion of counts of different types of white blood cells in the bone marrow, called differential counts, provides invaluable information to doctors for diagnosis. Due to the tedious nature of the differential white blood cell counting process, an automatic system is preferable. In this paper, we investigate whether information about the nucleus alone is adequate to classify white blood cells. This is important because segmentation of nucleus is much easier than the segmentation of the entire cell, especially in the bone marrow where the white blood cell density is very high. In the experiments, a set of manually segmented images of the nucleus are used to decouple segmentation errors. We analyze a set of white-blood-cell-nucleus-based features using mathematical morphology. Fivefold cross validation is used in the experiments in which Bayes' classifiers and artificial neural networks are applied as classifiers. The classification performances are evaluated by two evaluation measures: traditional and class wise classification rates. Furthermore, we compare our results with other classifiers and previously proposed nucleus-based features. The results show that the features using nucleus alone can be utilized to achieve a classification rate of 77% on the test sets. Moreover, the classification performance is better in the class wise sense when the a priori information is suppressed in both the classifiers.

Provably Secure Three-Party Authenticated Quantum Key Distribution Protocols (2007)

ABSTRACT
This work presents quantum key distribution protocols (QKDPs) to safeguard security in large networks, ushering in new directions in classical cryptography and quantum cryptography. Two three-party QKDPs, one with implicit user authentication and the other with explicit mutual authentication, are proposed to demonstrate the merits of the new combination, which include the following: 1) security against such attacks as man-in-the-middle, eavesdropping and replay, 2) efficiency is improved as the proposed protocols contain the fewest number of communication rounds among existing QKDPs, and 3) two parties can share and use a long-term secret (repeatedly). To prove the security of the proposed schemes, this work also presents a new primitive called the Unbiased-Chosen Basis (UCB) assumption.

Networking Abstracts

Compression-Free Checksum-Based Fault-Detection Schemes For Pipelined Processors (2011)

ABSTRACT
We propose a fault-detection scheme for pipelined, multithreaded processors. The scheme is based on checksums and improves on previous schemes in terms of fault coverage and detection latency by not using compression but storing complete checksums from several pipeline stages. We validate the scheme experimentally and derive checksum polynomials that lead to perfect fault coverage

Analysis of Shortest Path Routing for Large Multi-Hop Wireless Networks (2009)

ABSTRACT
In this paper, we analyze the impact of straight line routing in large homogeneous multi-hop wireless networks. We estimate the nodal load, which is defined as the number of packets served at a node, induced by straight line routing. For a given total offered load on the network, our analysis shows that the nodal load at each node is a function of the node's Voronoi cell, the node's location in the network, and the traffic pattern specified by the source and destination randomness and straight line routing. In the asymptotic regime, we show that each node's probability that the node serves a packet arriving to the network approaches the products of half the length of the Voronoi cell perimeter and the load density function that a packet goes through the node's location. The density function depends on the traffic pattern generated by straight line routing, and determines where the hot spot is created in the network. Hence, contrary to conventional wisdom, straight line routing can balance the load over the network, depending on the traffic patterns.

Delay Analysis for Maximal Scheduling With Flow Control in Wireless Networks With Bursty Traffic (2009)

ABSTRACT
We consider the delay properties of one-hop networks with general interference constraints and multiple traffic streams with time-correlated arrivals. We first treat the case when arrivals are modulated by independent finite state Markov chains. We show that the well known maximal scheduling algorithm achieves average delay that grows at most logarithmically in the largest number of interferers at any link. Further, in the important special case when each Markov process has at most two states (such as Bursty ON/OFF sources), we prove that average delay is independent of the number of nodes and links in the network, and hence is order-optimal. We provide tight delay bounds in terms of the individual auto-correlation parameters of the traffic sources. These are perhaps the first order-optimal delay results for controlled queuing networks that explicitly account for such statistical information. Our analysis treats cases both with and without flow control.

Explicit Load Balancing Technique for NGEO Satellite IP Networks with On-Board Processing Capability (2009)

ABSTRACT
Non-geostationary (NGEO) satellite communication systems offer an array of advantages over their terrestrial and geostationary counterparts. They are seen as an integral part of next generation ubiquitous communication systems. Given the non-uniform distribution of users in satellite footprints, due to several geographical and/or climatic constraints, some Inter-Satellite Links (ISLs) are expected to be heavily loaded with data packets while others remain underutilized. Such scenario obviously leads to congestion of the heavily loaded links. It ultimately results in buffer overflows, higher queuing delays, and significant packet drops. To guarantee a better distribution of traffic among satellites, this paper proposes an explicit exchange of information on congestion status among neighboring satellites. Indeed, a satellite notifies its congestion status to its neighboring satellites. When it is about to get congested, it requests its neighboring satellites to decrease their data forwarding rates by sending them a self status notification signaling message. In response, the neighboring satellites search for less congested paths that do not include the satellite in question and communicate a portion of data, primarily destined to the satellite, via the retrieved paths. This operation avoids both congestion and packet drops at the satellite. It also ensures a better distribution of traffic over the entire satellite constellation. The proposed scheme is dubbed "Explicit Load Balancing" (ELB) scheme. While the multi-path routing concept of ELB has many advantages, it may lead to persistent packet reordering. In case of connection-oriented protocols, this phenomenon results in unnecessary shrinkage of the data transmission rate. A solution to this issue is also incorporated in the design of ELB. The interactions of ELB with mechanisms that provide different QOS by differentiating traffic (e.g., Differentiated Services) are also discussed. The good performance of ELB, in terms of better traffic distribution, higher throughput, and lower packet drops, is verified via a set of simulations using the Network Simulator (NS).

Local Construction of Near-Optimal Power Spanners for Wireless Ad Hoc Networks (2009)

ABSTRACT
We present a local distributed algorithm that, given a wireless ad-hoc network modeled as a unit disk graph U in the plane, constructs a planar power spanner of U whose degree is bounded by k and whose stretch factor is bounded by 1+ (2 Sin /k)^þ , where k>=10 is an integer parameter and þ € [2,5] is the power exponent constant. For the same degree bound k, the stretch factor of our algorithm significantly improves the previous best bounds by Song et al. We show that this bound is near-optimal by proving that the slightly smaller stretch factor of 1+ (2 sin π/( k +1)) is unattainable for the same degree bound k . In contrast to previous algorithms for the problem, the presented algorithm is local. As a consequence, the algorithm is highly scalable and robust. Finally, while the algorithm is efficient and easy to implement in practice, it relies on deep insights on the geometry of unit disk graphs and novel techniques that are of independent interest.

PRESTO Feedback-Driven Data Management in Sensor Networks (2009)

ABSTRACT
This paper presents PRESTO, a novel two-tier sensor data management architecture comprising proxies and sensors that cooperate with one another for acquiring data and processing queries. PRESTO proxies construct time-series models of observed trends in the sensor data and transmit the parameters of the model to sensors. Sensors check sensed data with model-predicted values and transmit only deviations from the predictions back to the proxy. Such a model-driven push approach is energy-efficient, while ensuring that anomalous data trends are never missed. In addition to supporting queries on current data, PRESTO also supports queries on historical data using interpolation and local archival at sensors. PRESTO can adapt model and system parameters to data and query dynamics to further extract energy savings. We have implemented PRESTO on a sensor testbed comprising Intel Stargates and Telos Motes. Our experiments show that in a temperature monitoring application, PRESTO yields one to two orders of magnitude reduction in energy requirements over on-demand, proactive or model-driven pull approaches. PRESTO also results in an order of magnitude reduction in query latency in a 1% duty-cycled five hop sensor network over a system that forwards all queries to remote sensor nodes.

Re-sequencing Analysis of Stop-and-Wait ARQ for Parallel Multichannel Communications (2009)

ABSTRACT
In this paper, we consider a multichannel data communication system in which the stop-and-wait automatic-repeat request protocol for parallel channels with an in-sequence delivery guarantee (MSW-ARQ-INS) is used for error control. We evaluate the re-sequencing delay and the re-sequencing buffer occupancy, respectively. Under the assumption that all channels have the same transmission rate but possibly different time-invariant error rates, we derive the probability generating function of the re-sequencing buffer occupancy and the probability mass function of the re-sequencing delay. Then, by assuming the Gilbert–Elliott model for each channel, we extend our analysis to time-varying channels. Through examples, we compute the probability mass functions of the re-sequencing buffer occupancy and the re-sequencing delay for time-invariant channels. From numerical and simulation results, we analyze trends in the mean re-sequencing buffer occupancy and the mean re-sequencing delay as functions of system parameters. We expect that the modeling technique and analytical approach used in this paper can be applied to the performance evaluation of other ARQ protocols (e.g., the selective-repeat ARQ) over multiple time-varying channels.

Resource Allocation in OFDMA Wireless Communications Systems Supporting Multimedia Services (2009)

ABSTRACT
We design a resource allocation algorithm for downlink of orthogonal frequency division multiple access (OFDMA) systems supporting real-time (RT) and best-effort (BE) services simultaneously over a time-varying wireless channel. The proposed algorithm aims at maximizing system throughput while satisfying quality of service (QOS) requirements of the RT and BE services. We take two kinds of QOS requirements into account. One is the required average transmission rate for both RT and BE services. The other is the tolerable average absolute deviation of transmission rate (AADTR) just for the RT services, which is used to control the fluctuation in transmission rates and to limit the RT packet delay to a moderate level. We formulate the optimization problem representing the resource allocation under consideration and solve it by using the dual optimization technique and the projection stochastic sub gradient method. Simulation results show that the proposed algorithm well meets the QOS requirements with the high throughput and outperforms the modified largest weighted delay first (M-LWDF) algorithm that supports similar QOS requirements

Secure and Policy-Compliant Source Routing (2009)

ABSTRACT
In today's Internet, inter-domain route control remains elusive; nevertheless, such control could improve the performance, reliability, and utility of the network for end users and ISPs alike. While researchers have proposed a number of source routing techniques to combat this limitation, there has thus far been no way for independent ASes to ensure that such traffic does not circumvent local traffic policies, nor to accurately determine the correct party to charge for forwarding the traffic. We present Platypus, an authenticated source routing system built around the concept of network capabilities, which allow for accountable, fine-grained path selection by cryptographically attesting to policy compliance at each hop along a source route. Capabilities can be composed to construct routes through multiple. ASes and can be delegated to third parties. Platypus caters to the needs of both end users and ISPs: users gain the ability to pool their resources and select routes other than the default, while ISPs maintain control over where, when, and whose packets traverse their networks. We describe the design and implementation of an extensive Platypus policy framework that can be used to address several issues in wide-area routing at both the edge and the core, and evaluate its performance and security. Our results show that incremental deployment of Platypus can achieve immediate gains.

Single-Link Failure Detection in All-Optical Networks Using (2009)

ABSTRACT
In this paper, we consider the problem of fault localization in all-optical networks. We introduce the concept of monitoring cycles (MCs) and monitoring paths (MPs) for unique identification of single-link failures. MCs and MPs are required to pass through one or more monitoring locations. They are constructed such that any single-link failure results in the failure of a unique combination of MCs and MPs that pass through the monitoring location(s). For a network with only one monitoring location, we prove that three-edge connectivity is a necessary and sufficient condition for constructing MCs that uniquely identify any single-link failure in the network. For this case, we formulate the problem of constructing MCs as an integer linear program (ILP). We also develop heuristic approaches for constructing MCs in the presence of one or more monitoring locations. For an arbitrary network (not necessarily three-edge connected), we describe a fault localization technique that uses both MPs and MCs and that employs multiple monitoring locations. We also provide a linear-time algorithm to compute the minimum number of required monitoring locations. Through extensive simulations, we demonstrate the effectiveness of the proposed monitoring technique

Efficient Routing In Intermittently Connected Mobile Networks the Multiple Copy Case (2008)

ABSTRACT
Intermittently connected mobile networks are wireless networks where most of the time there does not exist a complete path from the source to the destination. There are many real networks that follow this model, for example, wildlife tracking sensor networks, military networks, vehicular ad hoc networks, etc. In this context, conventional routing schemes fail, because they try to establish complete end-to-end paths, before any data is sent. To deal with such networks researchers have suggested using flooding-based routing schemes. While flooding-based schemes have a high probability of delivery, they waste a lot of energy and suffer from severe contention which can significantly degrade their performance. Furthermore, proposed efforts to reduce the overhead of flooding-based schemes have often been plagued by large delays. With this in mind, we introduce a new family of routing schemes that "spray" a few message copies into the network, and then route each copy independently towards the destination. We show that, if carefully designed, spray routing not only performs significantly fewer transmissions per message, but also has lower average delivery delays than existing schemes; furthermore, it is highly scalable and retains good performance under a large range of scenarios.

On Guaranteed Smooth Switching for Buffered, Crossbar Switches (2008)

ABSTRACT
Scalability considerations drive the evolution of switch design from output queuing to input queuing and further to combined input and cross point queuing (CICQ). However, CICQ switches with credit-based flow control face new challenges of scalability and predictability. In this paper, we propose a novel approach of rate-based smoothed switching, and design a CICQ switch called the smoothed buffered crossbar or sBUX. First, the concept of smoothness is developed from two complementary perspectives of covering and spacing, which, commonly known as fairness and jitter, are unified in the same model. Second, a smoothed multiplexer sMUX is designed that allocates bandwidth among competing flows sharing a link and guarantees almost ideal smoothness for each flow. Third, the buffered crossbar sBUX is designed that uses the scheduler sMUX at each input and output, and a two-cell buffer at each cross point. It is proved that sBUX guarantees 100% throughput for real-time services and almost ideal smoothness for each flow. Fourth, an on-line bandwidth regulator is designed that periodically estimates bandwidth demand and generates admissible allocations, which enables sBUX to support best-effort services. Simulation shows almost 100% throughput and multi-microsecond average delay. In particular, neither credit-based flow control nor speedup is used, and arbitrary fabric-internal latency is allowed between line cards and the switch core, simplifying the switch implementation.

Probabilistic Packet Marking for Large-Scale IP Traceback (2008)

ABSTRACT
This paper presents an approach to IP Traceback based on the probabilistic packet marking paradigm. Our approach, which we call randomize-and-link, uses large checksum cords to "link" message fragments in a way that is highly scalable, for the checksums serve both as associative addresses and data integrity verifiers. The main advantage of these checksum cords is that they spread the addresses of possible router messages across a spectrum that is too large for the attacker to easily create messages that collide with legitimate messages.

Rate Allocation Network Lifetime Problem for Wireless Sensor Network (2008)

ABSTRACT
An important performance consideration for wireless sensor networks is the amount of information collected by all the nodes in the network over the course of network lifetime. Since the objective of maximizing the sum of rates of all the nodes in the network can lead to a severe bias in rate allocation among the nodes, we advocate the use of lexicographical max-min (LMM) rate allocation. To calculate the LMM rate allocation vector, we develop a polynomial-time algorithm by exploiting the parametric analysis (PA) technique from linear program (LP), which we call serial LP with Parametric Analysis (SLP-PA). We show that the SLP-PA can be also employed to address the LMM node lifetime problem much more efficiently than a state-of-the-art algorithm proposed in the literature. More important, we show that there exists an elegant duality relationship between the LMM rate allocation problem and the LMM node lifetime problem. Therefore, it is sufficient to solve only one of the two problems. Important insights can be obtained by inferring duality results for the other problem.

Rate less Forward Error Correction for Topology-Transparent Scheduling (2008)

ABSTRACT
Topology-transparent scheduling for mobile wireless ad hoc networks has been treated as a theoretical curiosity. This paper makes two contributions towards its practical deployment: 1) We generalize the combinatorial requirement on the schedules and show that the solution is a cover-free family. As a result, a much wider number and variety of constructions for schedules exist to match network conditions. 2) In simulation, we closely match the theoretical bound on expected throughput. The bound was derived assuming acknowledgments are available immediately. We use rate less forward error correction (RFEC) as an acknowledgment scheme with minimal computational overhead. Since the wireless medium is inherently unreliable, RFEC also offers some measure of automatic adaptation to channel load. These contributions renew interest in topology-transparent scheduling when delay is a principal objective.

Securing User-Controlled Routing Infrastructures (2008)

ABSTRACT
In this paper we design an infrastructure for preventing the un trusted parties getting access to the routing information. And also we are achieving flexible and efficient communication. However there are some difficulties in doing so they are the new security vulnerability that is introduced. The flexible control plane of these infrastructures can be exploited to launch many types of powerful attacks with little effort. In this paper, we make several contributions towards studying security issues in forwarding infrastructures (FIs). We present a general model for an FI; analyze potential security vulnerabilities, and present techniques to address these vulnerabilities. The main technique that we introduce in this paper is the use of simple lightweight cryptographic constraints on forwarding entries. We show that it is possible to prevent a large class of Attacks on end-hosts and bound the flooding attacks that can be launched on the infrastructure nodes to a small constant value

Statistical Techniques for Detecting Traffic Anomalies Through Packet Header Data (2008)

ABSTRACT
This paper proposes a traffic anomaly detector, operated in postmortem and in real-time, by passively monitoring packet headers of traffic. The frequent attacks on network infrastructure, using various forms of denial of service attacks, have led to an increased need for developing techniques for analyzing network traffic. If efficient analysis tools were available, it could become possible to detect the attacks, anomalies and to take action to contain the attacks appropriately before they have had time to propagate across the network. In this paper, we suggest a technique for traffic anomaly detection based on analyzing correlation of destination IP addresses in outgoing traffic at an egress router. This address correlation data are transformed using discrete wavelet transform for effective detection of anomalies through statistical analysis. Results from trace-driven evaluation suggest that proposed approach could provide an effective means of detecting anomalies close to the source. We also present a multidimensional indicator using the correlation of port numbers and the number of flows as a means of detecting anomalies.

Efficient Broadcasting using Network Coding (2008)

ABSTRACT
We consider the problem of broadcasting in an ad hoc wireless network, where all nodes of the network are sources that want to transmit information to all other nodes. Our figure of merit is energy efficiency, a critical design parameter for wireless networks since it directly affects battery life and thus network lifetime. We prove that applying ideas from network coding allows realizing significant benefits in terms of energy efficiency for the problem of broadcasting, and proposing very simple algorithms that allow realizing these benefits in practice. In particular, our theoretical analysis shows that network coding improves performance by a constant factor in fixed networks. We calculate this factor exactly for some canonical configurations. We then show that in networks where the topology dynamically changes, for example due to mobility, and where operations are restricted to simple distributed algorithms, network coding can offer improvements of a factor, where is the number of nodes in the network. We use the insights gained from the theoretical analysis to propose low-complexity distributed algorithms for realistic wireless ad hoc scenarios, discuss a number of practical considerations, and evaluate our algorithms through packet level simulation.

Hierarchical Pattern-Based Clustering for Grouping Web Transactions (2007)

ABSTRACT
Grouping customer transactions into segments is important in order to obtain better understanding of customers' pattern. Currently, the hierarchical pattern-based clustering has been used to group customer transactions into segments. However, the processing time is still high due to difference parameter used between two clusters. In this paper, the difference will be based on the different between the summations of each cluster. The simulation involving several sets of web data reveal that the proposed model improves the greedy hierarchical pattern-based clustering model up to fifty percent.

Data Mining

Improved K-Mean Clustering With Steepest Ascent (Gradient) Method For Image Retrieval (2011)

ABSTRACT
In this study we present a new frame work for clustering that uses an Improved K-Mean with Steepest ascent (Gradient) Technique. The basic idea of this paper is to use a Color Descriptors which work on RGB and HSV color space after that this result is used by Improved K Mean with Steepest ascent (Gradient) algorithm. In which it used a heuristic local search algorithm that provide additional information about the solution. In this direction it gives the effective result of clustering that provide stability and performs better in global searching..

Data leakage detection (2010)

ABSTRACT
A data distributor has given sensitive data to a set of supposedly trusted agents (third parties). Some of the data is leaked and found in an unauthorized place (e.g., on the web or somebody's laptop). The distributor must assess the likelihood that the leaked data came from one or more agents, as opposed to having been independently gathered by other means. We propose data allocation strategies (across the agents) that improve the probability of identifying leakages. These methods do not rely on alterations of the released data (e.g., watermarks). In some cases we can also inject "realistic but fake" data records to further improve our chances of detecting leakage and identifying the guilty party.

Enforcing Minimum-Cost Multicast Routing against Shelfish Information Flows (2009)

ABSTRACT
We study multicast in a non cooperative environment where information flows selfishly route themselves through the cheapest paths available. The main challenge is to enforce such selfish multicast flows to stabilize at a socially optimal operating point incurring minimum total edge cost, through appropriate cost allocation and other economic measures, with replicable and encodable properties of information flows considered. We show that known cost allocation schemes are not sufficient. We provide a shadow-price-based cost allocation for networks without capacity limits and show that it enforces minimum-cost multicast. This improves previous result where a 2-approximate multicast flow is enforced. For capacitated networks, computing cost allocation by ignoring edge capacities will not yield correct results. We show that an edge tax scheme can be combined with a cost allocation to strictly enforce optimal multicast flows in this more realistic case. If taxes are not desirable, they can be returned to flows while maintaining weak enforcement of the optimal flow. We relate the taxes to VCG payment schemes and discuss an efficient primal-dual algorithm that simultaneously computes the taxes, the cost allocation, and the optimal multicast flow, with potential of fully distributed implementations.

A Survey on Privacy Preserving Data Mining (2009)

ABSTRACT
Privacy preserving becomes an important issue in the development progress of data mining techniques. Privacy preserving data mining has become increasingly popular because it allows sharing of privacy-sensitive data for analysis purposes. So people have become increasingly unwilling to share their data, frequently resulting in individuals either refusing to share their data or providing incorrect data. In turn, such problems in data collection can affect the success of data mining, which relies on sufficient amounts of accurate data in order to produce meaningful results. In recent years, the wide availability of personal data has made the problem of privacy preserving data mining an important one. A number of methods have recently been proposed for privacy preserving data mining of multidimensional data records. This paper intends to reiterate several privacy preserving data mining technologies clearly and then proceeds to analyze the merits and shortcomings of these technologies.

Hardware enhanced association rule mining with Hashing and Pipelining (2008)

ABSTRACT
Generally speaking, to implement Apriori-based association rule mining in hardware, one has to load candidate itemsets and a database into the hardware. Since the capacity of the hardware architecture is fixed, if the number of candidate itemsets or the number of items in the database is larger than the hardware capacity, the items are loaded into the hardware separately. The time complexity of those steps that need to load candidate itemsets or database items into the hardware is in proportion to the number of candidate itemsets multiplied by the number of items in the database. Too many candidate itemsets and a large database would create a performance bottleneck. In this paper, we propose a Hash-based and Pipelined (abbreviated as HAPPI) architecture for hardware enhanced association rule mining. We apply the pipeline methodology in the HAPPI architecture to compare itemsets with the database and collect useful information for reducing the number of candidate item sets and items in the database simultaneously. When the database is fed into the hardware, candidate itemsets are compared with the items in the database to find frequent itemsets. At the same time, trimming information is collected from each transaction. In addition, itemsets are generated from transactions and hashed into a hash table. The useful trimming information and the hash table enable us to reduce the number of items in the database and the number of candidate itemsets. Therefore, we can effectively reduce the frequency of loading the database into the hardware. As such, HAPPI solves the bottleneck problem in a priori-based hardware schemes. We also derive some properties to investigate the performance of this hardware implementation. As shown by the experiment results, HAPPI significantly outperforms the previous hardware approach and the software algorithm in terms of execution time.

Semantic Ideation Learning for Agent- Based E-Brainstorming (2008)

ABSTRACT
Brainstorming can assist organizations in generating creative ideas using teamwork and collaboration. However, the role of information technology in brainstorming is merely that of an assistant that passively supports the progression of brainstorming sessions rather than proactively engaging in the sessions. This paper integrates the unique association thinking of humans with an intelligent agent technique to devise an automated decision agent called the Semantic Ideation Learning Agent (SILA) that can represent a session participant who is actively participating in brainstorming. SILAs are grounded on the three association capabilities of human thinking (similarity, contiguity, and contrast). Furthermore, a Collective Brainstorming Decision System (CBDS) is built to construct an environment where SILAs can learn and share their knowledge with each other. Additionally, CBDS is integrated into an intelligent care project (i-Care) for the purpose of innovated e-service recommendation. Preliminarily, evaluation results indicate that the proposed system advances e-brainstorming by crossing the three key boundaries of human ideation capability (understanding, cognition boundary, and endurance)

Analyzing and Managing Role-Based Access Control Policies (2008)

ABSTRACT
In the computerized world all the data are saved on electronically. It also contains more sensitive data. In computer systems security, role-based access control is an approach to restricting system access to authorized users. It is a newer alternative approach to mandatory access control and discretionary access control. Security critical business processes are mapped to their digital governments. It needs different security requirements, such as healthcare industry, digital government, and financial service institute. So the authorization and authentication play a vital role. Authorization constraints help the policy architect design and express higher level organizational rules. Access is the ability to do something with a computer resource (e.g., use, change, or view). Access control is the means by which the ability is explicitly enabled or restricted in some way (usually through physical and system-based controls). Computer- based access controls can prescribe not only who or what process may have access to a specific system resource, but also the type of access that is permitted. These controls may be implemented in the computer system or in external devices.

XML Database Migration (2008)

ABSTRACT
As technology evolves over time, a common problem is the migration of software applications from one technology base to another. This paper is a practical experience report based on IBM Net. It is Commerce to Web Sphere Commerce Suite (WCS) migration. It identifies the problems and issues in the migration of applications using traditional database access (SQL) to applications using the Enterprise Java Bean (EJB) programming model, and presents a practical methodology in facilitating such migration. It also describes a tool built on this methodology that has been released on IBM's alpha Works site. From the experience so gained, this paper points to a number of future enhancement areas in the methodology and associated technology research.

Hiding Sensitive Association Rules with Limited Side Effects (2007)

ABSTRACT
Data mining techniques have been widely used in various applications. However, the misuse of these techniques may lead to the disclosure of sensitive information. Researchers have recently made efforts at hiding sensitive association rules. Nevertheless, undesired side effects, e.g., non-sensitive rules falsely hidden and spurious rules falsely generated may be produced in the rule hiding process. In this paper, we present a novel approach that strategically modifies a few transactions in the transaction database to decrease the supports or confidences of sensitive rules without producing the side effects. Since the correlation among rules can make it impossible to achieve this goal, in this paper, we propose heuristic methods for increasing the number of hidden sensitive rules and reducing the number of modified entries. The experimental results show the effectiveness of our approach, i.e., undesired side effects are avoided in the rule hiding process. The results also report that in most cases, all the sensitive rules are hidden without spurious rules falsely generated. Moreover, the good scalability of our approach in terms of database size and the influence of the correlation among rules on rule hiding are observed.

Clustering and Sequential Pattern Mining of Online Collaborative Learning Data (2007)

ABSTRACT
Group work is widespread in education. The growing use of online tools supporting group work generates huge amounts of data. We aim to exploit this data to support mirroring: presenting useful high-level views of information about the group, together with desired patterns characterizing the behavior of strong groups. The goal is to enable the groups and their facilitators to see relevant aspects of the group's operation and provide feedback if these are more likely to be associated with positive or negative outcomes and where the problems are. We explore how useful mirror information can be extracted via a theory-driven approach and a range of clustering and sequential pattern mining. The context is a senior software development project where students use the collaboration tool TRAC. We extract patterns distinguishing the better from the weaker groups and get insights in the success factors. The results point to the importance of leadership and group interaction, and give promising indications if they are occurring. Patterns indicating good individual practices were also identified. We found that some key measures can be mined from early data. The results are promising for advising groups at the start and early identification of effective and poor practices, in time for remediation.

Visual Web Mining of Organizational Web Sites (2006)

ABSTRACT
Existing web usage mining (WUM) tools do not indicate which data mining algorithms are used or provide effective graphical visualizations of the results obtained. WUM techniques can be used to determine typical navigation patterns in an organizational web site. The process of combining WUM and information visualization techniques in order to discover useful information about web usage patterns is called visual web mining. The goal of this paper is to discuss the development of a visual web mining prototype, called Web Patterns, which allows the user to effectively visualize web usage patterns.

Workflow Mining: Discovering Process Models from Event Logs (2004)

ABSTRACT
Contemporary workflow management systems are driven by explicit process models, i.e., a completely specified workflow design is required in order to enact a given workflow process. Creating a workflow design is a complicated time-consuming process and, typically, there are discrepancies between the actual workflow processes and the processes as perceived by the management. Therefore, we have developed techniques for discovering workflow models. The starting point for such techniques is a so-called "workflow log" containing information about the workflow process as it is actually being executed. We present a new algorithm to extract a process model from such a log and represent it in terms of a Petri net. However, we will also demonstrate that it is not possible to discover arbitrary workflow processes. In this paper, we explore a class of workflow processes that can be discovered. We show that the algorithm can successfully mine any workflow represented by a so-called SWF-net

Parallel And Distributed Systems

Resource Overbooking: Using Aggregation Profiling In Large Scale Resource Discovery (2011)

ABSTRACT
Resource discovery is an important process for finding suitable nodes that satisfy application requirements in large loosely coupled distributed systems. Besides inter node heterogeneity, many of these systems also show a high degree of intra node dynamism, so that selecting nodes based only on their recently observed resource capacities can lead to poor deployment decisions resulting in application failures or migration overheads. However, most existing resource discovery mechanisms rely mainly on recent observations to achieve scalability in large systems. In this paper, we propose the notion of a resource bundle—a representative resource usage distribution for a group of nodes with similar resource usage patterns—that employs two complementary techniques to overcome the limitations of existing techniques: resource usage histograms to provide statistical guarantees for resource capacities and clustering-based resource aggregation to achieve scalability. Using trace-driven simulations and data analysis of a month-long Planet Lab trace, we show that resource bundles are able to provide high accuracy for statistical resource discovery, while achieving high scalability. We also show that resource bundles are ideally suited for identifying group-level characteristics (e.g., hot spots, total group capacity).

Movement-Assisted Connectivity Restoration in Wireless Sensor and Actor Networks (2009)

ABSTRACT
Recent years have witnessed a growing interest in applications of wireless sensor and actor networks (WSANs). In these applications, a set of mobile actor nodes are deployed in addition to sensors in order to collect sensors' data and perform specific tasks in response to detected events/objects. In most scenarios, actors have to respond collectively, which requires interactor coordination. Therefore, maintaining a connected interactor network is critical to the effectiveness of WSANs. However, WSANs often operate unattended in harsh environments where actors can easily fail or get damaged. An actor failure may lead to partitioning the interactor network and thus hinder the fulfillment of the application requirements. In this paper, we present DARA, a Distributed Actor Recovery Algorithm, which opts to efficiently restore the connectivity of the interactor network that has been affected by the failure of an actor. Two variants of the algorithm are developed to address 1- and 2-connectivity requirements. The idea is to identify the least set of actors that should be repositioned in order to reestablish a particular level of connectivity. DARA strives to localize the scope of the recovery process and minimize the movement overhead imposed on the involved actors. The effectiveness of DARA is validated through simulation experiments.

Compaction of Schedules and a Two-Stage Approach for Duplication (2008)

ABSTRACT
Many DAG scheduling algorithms generate schedules that require prohibitively large number of processors. To address this problem, we propose a generic algorithm, SC, to minimize the processor requirement of any given valid schedule. SC preserves the schedule length of the original schedule and reduces processor count by merging processor schedules and removing redundant duplicate tasks. To the best of our knowledge, this is the first algorithm to address this highly unexplored aspect of DAG scheduling. On the average, SC reduced the processor requirement 91%, 82% and 72% for schedules generated by PLW, TCSD and CPFD algorithms, respectively. SC algorithm has a low complexity when compared to most duplication based algorithms. Moreover, it decouples processor economization from schedule length minimization problem. To take advantage of these features of SC, we also propose a scheduling algorithm SDS, having the same time complexity as SC. Our experiments demonstrate that, schedules generated by SDS are only 3% longer than CPFD, one of the best algorithms in that respect. SDS and SC together form a two-stage scheduling algorithm that produces schedules with high quality and low processor requirement, and has lower complexity than the comparable algorithms that produce similar high quality results.

HBA Distributed Metadata Management for Large Cluster-Based Storage Systems (2008)

ABSTRACT
An efficient and distributed scheme for file mapping or file lookup is critical in decentralizing metadata management within a group of metadata servers. This paper presents a novel technique called Hierarchical Bloom Filter Arrays (HBA) to map filenames to the metadata servers holding their metadata. Two levels of probabilistic arrays, namely, the Bloom filter arrays with different levels of accuracies, are used on each metadata server. One array, with lower accuracy and representing the distribution of the entire metadata, trades accuracy for significantly reduced memory overhead, whereas the other array, with higher accuracy, caches partial distribution information and exploits the temporal locality of file access patterns. Both arrays are replicated to all metadata servers to support fast local lookups. We evaluate HBA through extensive trace-driven simulations and implementation in Linux. Simulation results show our HBA design to be highly effective and efficient in improving the performance and scalability of file systems in clusters with 1,000 to 10,000 nodes (or superclusters) and with the amount of data in the petabyte scale or higher. Our implementation indicates that HBA can reduce the metadata operation time of a single-metadata-server architecture by a factor of up to 43.9 when the system is configured with 16 metadata servers.

An SSL Back-End Forwarding Scheme in Cluster-Based Web Servers (2007)

ABSTRACT
State-of-the-art cluster-based data centers consisting of three tiers (Web server, application server, and database server) are being used to host complex Web services such as e-commerce applications. The application server handles dynamic and sensitive Web contents that need protection from eavesdropping, tampering, and forgery. Although the Secure Sockets Layer (SSL) is the most popular protocol to provide a secure channel between a client and a cluster-based network server, its high overhead degrades the server performance considerably and, thus, affects the server scalability. Therefore, improving the performance of SSL-enabled network servers is critical for designing scalable and high-performance data centers. In this paper, we examine the impact of SSL offering and SSL-session-aware distribution in cluster-based network servers. We propose a back-end forwarding scheme, called ssl_with_bf, that employs a low-overhead user-level communication mechanism like Virtual Interface Architecture (VIA) to achieve a good load balance among server nodes. We compare three distribution models for network servers, Round Robin (RR), ssl_with_session, and ssl_with_bf, through simulation. The experimental results with 16-node and 32-node cluster configurations show that, although the session reuse of ssl_with_session is critical to improve the performance of application servers, the proposed back-end forwarding scheme can further enhance the performance due to better load balancing. The ssl_with_bf scheme can minimize the average latency by about 40 percent and improve throughput across a variety of workloads

P-Fusion : A P2P Architecture for Internet-Scale Content-Based Search and Retrieval (2007)

ABSTRACT
The emerging Peer-to-Peer (P2P) model has become a very powerful and attractive paradigm for developing Internet-scale systems for sharing resources, including files and documents. The distributed nature of these systems, where nodes are typically located across different networks and domains, inherently hinders the efficient retrieval of information. In this paper, we consider the effects of topologically aware overlay construction techniques on efficient P2P keyword search algorithms. We present the Peer Fusion (P-Fusion) architecture that aims to efficiently integrate heterogeneous information that is geographically scattered on peers of different networks. Our approach builds on work in unstructured P2P systems and uses only local knowledge. Our empirical results, using the P-Fusion middleware architecture and data sets from AKAMAI's Internet mapping infrastructure (AKAMAI), the Active Measurement Project (NLANR), and the Text Retrieval Conference (TREC) show that the architecture we propose is both efficient and practical.

Policies for Caching OLAP Queries (2006)

ABSTRACT
The Internet now offers more than just simple information to the users. Decision makers an now issue analytical queries in order to identify useful trends and patterns. Such queries are often referred to as On-Line-Analytical Processing (OLAP). Typically, pages carrying query results do not exhibit temporal locality and, therefore, are not considered for caching at Internet proxies. This project reduces the response time for OLAP queries originating from geographically distributed private LANs. The theme of our project is to formulate a cost model for characterizing the respective latencies, taking into consideration the combined effects of both common Web access and query processing. We use a cache admittance that operates on a Web-OLAP input, outperforming both pure-Web and pure-OLAP caching schemes

Mobile Computing

Adaptive Fault Tolerant Qos Control Algorithms For Maximizing System Lifetime Of Query-Based Wireless Sensor Networks (2011)

ABSTRACT
Data sensing and retrieval in wireless sensor systems have a widespread application in areas such as security and surveillance monitoring, and command and control in battlefields. In query-based wireless sensor systems, a user would issue a query and expect a response to be returned within the deadline. While the use of fault tolerance mechanisms through redundancy improves query reliability in the presence of unreliable wireless communication and sensor faults, it could cause the energy of the system to be quickly depleted. Therefore, there is an inherent tradeoff between query reliability vs. energy consumption in query-based wireless sensor systems. In this paper, we develop adaptive fault tolerant quality of service (QoS) control algorithms based on hop-by-hop data delivery utilizing "source" and "path" redundancy, with the goal to satisfy application QoS requirements while prolonging the lifetime of the sensor system. We develop a mathematical model for the lifetime of the sensor system as a function of system parameters including the "source" and "path" redundancy levels utilized. We discover that there exists optimal "source" and "path" redundancy under which the lifetime of the system is maximized while satisfying application QoS requirements. Numerical data are presented and validated through extensive simulation, with physical interpretations given, to demonstrate the feasibility of our algorithm design

A TABU Search Algorithm for Cluster Building in Wireless Sensor Networks (2009)

ABSTRACT
The main challenge in wireless sensor network deployment pertains to optimizing energy consumption when collecting data from sensor nodes. This paper proposes a new centralized clustering method for a data collection mechanism in wireless sensor networks, which is based on network energy maps and Quality-of-Service (QOS) requirements. The clustering problem is modeled as a hyper graph partitioning and its resolution is based on a TABU search heuristic. Our approach defines moves using largest size cliques in a feasibility cluster graph. Compared to other methods (CPLEX-based method, distributed method, simulated annealing-based method), the results show that our TABU search-based approach returns high-quality solutions in terms of cluster cost and execution time. As a result, this approach is suitable for handling network extensibility in a satisfactory manner.

Biased Random Walks in Uniform Wireless Networks (2009)

ABSTRACT
A recurrent problem when designing distributed applications is to search for a node with known property. File searching in peer-to-peer (P2P) applications, resource discovery in service-oriented architectures (SOAs), and path discovery in routing can all be cast as a search problem. Random walk-based search algorithms are often suggested for tackling the search problem, especially in very dynamic systems-like mobile wireless networks. The cost and the effectiveness of a random walk-based search algorithm are measured by the excepted number of transmissions required before hitting the target. Hence, to have a low hitting time is a critical goal. This paper studies the effect of biasing random walk toward the target on the hitting time. For a walk running over a network with uniform node distribution, a simple upper bound that connects the hitting time to the bias level is obtained. The key result is that even a modest bias level is able to reduce the hitting time significantly. This paper also proposes a search protocol for mobile wireless networks, whose results are interpreted in the light of the theoretical study. The proposed solution is for unstructured wireless mobile networks.

Cell Breathing Techniques for Load Balancing in Wireless LANs (2009)

ABSTRACT
Maximizing network throughput while providing fairness is one of the key challenges in wireless LANs (WLANs). This goal is typically achieved when the load of access points (APs) is balanced. Recent studies on operational WLANs, however, have shown that AP load is often substantially uneven. To alleviate such imbalance of load, several load balancing schemes have been proposed. These schemes commonly require proprietary software or hardware at the user side for controlling the user-AP association. In this paper we present a new load balancing technique by controlling the size of WLAN cells (i.e., AP's coverage range), which is conceptually similar to cell breathing in cellular networks. The proposed scheme does not require any modification to the users neither the IEEE 802.11 standard. It only requires the ability of dynamically changing the transmission power of the AP beacon messages. We develop a set of polynomial time algorithms that find the optimal beacon power settings which minimize the load of the most congested AP. We also consider the problem of network-wide min-max load balancing. Simulation results show that the performance of the proposed method is comparable with or superior to the best existing association-based methods.

Energy Maps for Mobile Wireless Networks: Coherence Time versus Spreading Period (2009)

ABSTRACT
We show that even though mobile networks are highly unpredictable when viewed at the individual node scale, the end-to-end quality-of-service (QoS) metrics can be stationary when the mobile network is viewed in the aggregate. We define the coherence time as the maximum duration for which the end-to-end QoS metric remains roughly constant, and the spreading period as the minimum duration required to spread QoS information to all the nodes. We show that if the coherence time is greater than the spreading period, the end-to-end QoS metric can be tracked. We focus on the energy consumption as the end-to-end QoS metric, and describe a novel method by which an energy map can be constructed and refined in the joint memory of the mobile nodes. Finally, we show how energy maps can be utilized by an application that aims to minimize a node's total energy consumption over its near-future trajectory.

Greedy Routing with Anti Void Traversal for Wireless Sensor Networks (2009)

ABSTRACT
The un-reachability problem (i.e., the so-called void problem) that exists in the greedy routing algorithms has been studied for the wireless sensor networks. Some of the current research work cannot fully resolve the void problem, while there exist other schemes that can guarantee the delivery of packets with the excessive consumption of control overheads. In this paper, a greedy anti-void routing (GAR) protocol is proposed to solve the void problem with increased routing efficiency by exploiting the boundary finding technique for the unit disk graph (UDG). The proposed rolling-ball UDG boundary traversal (RUT) is employed to completely guarantee the delivery of packets from the source to the destination node under the UDG network. The boundary map (BM) and the indirect map searching (IMS) scheme are proposed as efficient algorithms for the realization of the RUT technique. Moreover, the hop count reduction (HCR) scheme is utilized as a short-cutting technique to reduce the routing hops by listening to the neighbor's traffic, while the intersection navigation (IN) mechanism is proposed to obtain the best rolling direction for boundary traversal with the adoption of shortest path criterion. In order to maintain the network requirement of the proposed RUT scheme under the non-UDG networks, the partial UDG construction (PUC) mechanism is proposed to transform the non-UDG into UDG setting for a portion of nodes that facilitate boundary traversal. These three schemes are incorporated within the GAR protocol to further enhance the routing performance with reduced communication overhead. The proofs of correctness for the GAR scheme are also given in this paper. Comparing with the existing localized routing algorithms, the simulation results show that the proposed GAR-based protocols can provide better routing efficiency.

Information Content-Based Sensor Selection and Transmission Power Adjustment for Collaborative Target Tracking (2009)

ABSTRACT
For target tracking applications, wireless sensor nodes provide accurate information since they can be deployed and operated near the phenomenon. These sensing devices have the opportunity of collaboration among themselves to improve the target localization and tracking accuracies. An energy-efficient collaborative target tracking paradigm is developed for wireless sensor networks (WSNs). A mutual-information-based sensor selection (MISS) algorithm is adopted for participation in the fusion process. MISS allows the sensor nodes with the highest mutual information about the target state to transmit data so that the energy consumption is reduced while the desired target position estimation accuracy is met. In addition, a novel approach to energy savings in WSNs is devised in the information-controlled transmission power (ICTP) adjustment, where nodes with more information use higher transmission powers than those that are less informative to share their target state information with the neighboring nodes. Simulations demonstrate the performance gains offered by MISS and ICTP in terms of power consumption and target localization accuracy.

On the Planning of Wireless Sensor Networks Energy-Efficient Clustering under the Joint Routing and Coverage Constraint< (2009)

ABSTRACT
Minimizing energy dissipation and maximizing network lifetime are important issues in the design of applications and protocols for sensor networks. Energy-efficient sensor state planning consists in finding an optimal assignment of states to sensors in order to maximize network lifetime. For example, in area surveillance applications, only an optimal subset of sensors that fully covers the monitored area can be switched on while the other sensors are turned off. In this paper, we address the optimal planning of sensors' states in cluster-based sensor networks. Typically, any sensor can be turned on, turned off, or promoted cluster head, and a different power consumption level is associated with each of these states. We seek an energy-optimal topology that maximizes network lifetime while ensuring simultaneously full area coverage and sensor connectivity to cluster heads, which are constrained to form a spanning tree used as a routing topology. First, we formulate this problem as an Integer Linear Programming model that we prove NP-Complete. Then, we implement a Tabu search heuristic to tackle the exponentially increasing computation time of the exact resolution. Experimental results show that the proposed heuristic provides near-optimal network lifetime values within low computation times, which is, in practice, suitable for large-sized sensor networks.

Random Cast : An Energy-Efficient Communication Scheme for Mobile Ad Hoc Networks (2009)

ABSTRACT
In mobile ad hoc networks (MANETs), every node overhears every data transmission occurring in its vicinity and thus, consumes energy unnecessarily. However, since some MANET routing protocols such as Dynamic Source Routing (DSR) collect route information via overhearing, they would suffer if they are used in combination with 802.11 PSM. Allowing no overhearing may critically deteriorate the performance of the underlying routing protocol, while unconditional overhearing may offset the advantage of using PSM. This paper proposes a new communication mechanism, called Random Cast, via which a sender can specify the desired level of overhearing, making a prudent balance between energy and routing performance. In addition, it reduces redundant rebroadcasts for a broadcast packet, and thus, saves more energy. Extensive simulation using ns-2 shows that Random Cast is highly energy-efficient compared to conventional 802.11 as well as 802.11 PSM-based schemes, in terms of total energy consumption, energy good put, and energy balance.

Route Stability in MANETs under the Random Direction Mobility Model (2009)

ABSTRACT
A fundamental issue arising in mobile ad hoc networks (MANETs) is the selection of the optimal path between any two nodes. A method that has been advocated to improve routing efficiency is to select the most stable path so as to reduce the latency and the overhead due to route reconstruction. In this work, we study both the availability and the duration probability of a routing path that is subject to link failures caused by node mobility. In particular, we focus on the case where the network nodes move according to the Random Direction model, and we derive both exact and approximate (but simple) expressions of these probabilities. Through our results, we study the problem of selecting an optimal route in terms of path availability. Finally, we propose an approach to improve the efficiency of reactive routing protocols. Algorithm /Technique: Random Direction model.

Efficient Broadcasting with Guaranteed Coverage in Mobile AD-HOC Networks (2008)

ABSTRACT
We study an efficient broadcast scheme in mobile ad hoc networks (MANETs). The objective is to determine a small set of forward nodes to ensure full coverage. We first study several methods that guarantee coverage when the local view of each node on its neighborhood information is updated in a timely manner. Then we consider a general case, where nodes move even during the broadcast process, making it impractical to maintain up-to-date and consistent local views. A formal framework is used to model inaccurate local views in MANETs, where full coverage is guaranteed if three sufficient conditions, connectivity, link availability, and consistency, are met. Three solutions are proposed to satisfy those conditions. First we give a minimal transmission range that maintains the connectivity of the virtual network constructed from local views. Then we use two transmission ranges, one for neighborhood information collection and the other for actual data transmission, to form a buffer zone that guarantees the availability of logical links in the physical network. Finally we propose a mechanism called aggregated local view to ensure consistent local views. By these, we extend Wu and Dai's coverage condition for broadcasting in a network with mobile nodes. The effectiveness of the proposed scheme is confirmed via both performance analysis and simulation study.

Efficient Resource Allocation for Wireless Multicast (2008)

ABSTRACT
In this paper, we propose a bandwidth-efficient multicast mechanism for heterogeneous wireless networks. We reduce the bandwidth cost of an Internet Protocol (IP) multicast tree by adaptively selecting the cell and the wireless technology for each mobile host to join the multicast group. Our mechanism enables more mobile hosts to cluster together and leads to the use of fewer cells to save the scarce wireless bandwidth. Besides, the paths in the multicast tree connecting to the selected cells share more common links to save the wireline bandwidth. Our mechanism supports the dynamic group membership and offers mobility of group members. Moreover, our mechanism requires no modification to the current IP multicast routing protocols. We formulate the selection of the cell and the wireless technology for each mobile host in the heterogeneous wireless networks as an optimization problem. We use Integer Linear Programming to model the problem and show that the problem is NP-hard. To solve the problem, we propose a distributed algorithm based on Lagrangean relaxation and a network protocol based on the algorithm. The simulation results show that our mechanism can effectively save the wireless and wireline bandwidth as compared to the traditional IP multicast.

Localized Sensor Area Coverage with Low Communication Overhead (2008)

ABSTRACT
We propose several localized sensor area coverage protocols for heterogeneous sensors, each with arbitrary sensing and transmission radii. The approach has a very small communication overhead since prior knowledge about neighbor existence is not required. Each node selects a random time out and listens to messages sent by other nodes before the time out expires. Sensor nodes whose sensing area is not fully covered (or fully covered but with a disconnected set of active sensors) when the deadline expires decide to remain active for the considered round and transmit an activity message announcing it. There are four variants in our approach, depending on whether or not withdrawal and retreat messages are transmitted. Covered nodes decide to sleep, with or without transmitting a withdrawal message to inform neighbors about the status. After hearing from more neighbors, active sensors may observe that they became covered and may decide to alter their original decision and transmit a retreat message. Our simulations show a largely reduced message overhead while preserving coverage quality for the ideal MAC/physical layer. Compared to an existing method (based on hello messages followed by retreat ones and where excessive message loss contributed to excessive coverage holes), our approach has shown robustness in a model with collisions and/or a realistic physical layer.

Image Processing

DWT based invisible image watermarking algorithm for color images (2011)

ABSTRACT

A Novel Framework for Semantic Annotation and Personalized Retrieval of Sports Video (2008)

ABSTRACT

Active Learning Methods for Interactive Image Retrieval (2008)

ABSTRACT

Orthogonal Data Embedding for Binary Images in Morphological Transform Domain-A High-Capacity Approach (2008)

ABSTRACT

Vision Based Processing For Real-Time 3-D Data Acquisition Based On Coded Structured Light (2008)

ABSTRACT

A Coupled Statistical Model for Face Shape Recovery from Brightness Images (2007)

ABSTRACT

Detecting Wide Lines Using Isotropic Nonlinear Filtering (2007)

ABSTRACT

Digital Image Processing Techniques for the Detection and Removal of Cracks in Digitized Paintings (2006)

ABSTRACT
An integrated methodology for the detection and removal of cracks on digitized paintings is presented in this paper. The cracks are detected by thresholding the output of the morphological top-hat transform. Afterward, the thin dark brush strokes which have been misidentified as cracks are removed using either a median radial basis function neural network on hue and saturation data or a semi-automatic procedure based on region growing. Finally, crack filling using order statistics filters or controlled anisotropic diffusion is performed. The methodology has been shown to perform very well on digitized paintings suffering from cracks.

Software Engineering

The Effect of Pairs in Program Design Tasks (2008)

ABSTRACT
Pair programming involves two developers simultaneously collaborating with each other on the same programming task to design and code a solution. Algorithm design and its implementation are normally interwoven in that implementation often provides feedback to enhance the design. Previous controlled pair programming experiments did not explore the efficacy of pairs versus individuals in program design-related tasks separately from coding. Variations in programmer skills in a particular language or an integrated development environment and the understanding of programming instructions can mask the skill of subjects in program design-related tasks. Programming aptitude tests (PATs) have been shown to correlate with programming performance. PATs do not require understanding of programming instructions and do not require a skill in any specific computer language. Two controlled experiments were conducted, with full-time professional programmers being the subjects who worked on increasingly complex programming aptitude tasks related to problem solving and algorithmic design. In both experiments, pairs significantly outperformed individuals, providing evidence of the value of pairs in program design-related tasks.

Estimation of Defects Based on Defect Decay Model ED3M (2008)

ABSTRACT
An accurate prediction of the number of defects in a software product during system testing contributes not only to the management of the system testing process but also to the estimation of the product's required maintenance. Here, a new approach, called Estimation of Defects based on Defect Decay Model (ED3M) is presented that computes an estimate of the total number of defects in an ongoing testing process. ED3M is based on estimation theory. Unlike many existing approaches, the technique presented here does not depend on historical data from previous projects or any assumptions about the requirements and/or testers' productivity. It is a completely automated approach that relies only on the data collected during an ongoing testing process. This is a key advantage of the ED3M approach as it makes it widely applicable in different testing environments. Here, the ED3M approach has been evaluated using five data sets from large industrial projects and two data sets from the literature. In addition, a performance analysis has been conducted using simulated data sets to explore its behavior using different models for the input data. The results are very promising; they indicate the ED3M approach provides accurate estimates with as fast or better convergence time in comparison to well-known alternative techniques, while only using defect data as the input.

Semantics Based Design for Secure Web Services (2008)

ABSTRACT
We outline a methodology for designing and composing services in a secure manner. In particular, we are concerned with safety properties of service behavior. Services can enforce security policies locally and can invoke other services that respect given security contracts. This call-by-contract mechanism offers a significant set of opportunities, each driving secure ways to compose services. We discuss how we can correctly plan service compositions in several relevant classes of services and security properties. With this aim, we propose a graphical modeling framework based on a foundational calculus called λreq [13]. Our formalism features dynamic and static semantics, thus allowing for formal reasoning about systems. Static analysis and model checking techniques provide the designer with useful information to assess and fix possible vulnerabilities.

API-Based and Information-Theoretic Metrics for Measuring the Quality of Software Modularization (2007)

ABSTRACT
We present in this paper a new set of metrics that measure the quality of modularization of a non-object-oriented software system. We have proposed a set of design principles to capture the notion of modularity and defined metrics centered on these principles. These metrics characterize the software from a variety of perspectives: structural, architectural, and notions such as the similarity of purpose and commonality of goals. (By structural, we are referring to inter module coupling-based notions, and by architectural, we mean the horizontal layering of modules in large software systems.) We employ the notion of API (Application Programming Interface) as the basis for our structural metrics. The rest of the metrics we present are in support of those that are based on API. Some of the important support metrics include those that characterize each module on the basis of the similarity of purpose of the services offered by the module. We tested our metrics on some popular open source systems and some large legacy-code business applications. To validate the metrics, we compared the results obtained on human-modularized versions of the software with those obtained on randomized versions of the code. For randomized versions, the assignment of the individual functions to modules was randomized

Neural Networks

Digit Recognition System Using Back Propagation Neural Network (2011)

ABSTRACT
Digits are used in different types of data like vehicle number plate, numeric data, written data, meter reading etc. Digit recognition plays an important role in many user authentication applications in the modern world. In the proposed work, back propagation neural network based digit recognition system has been developed. Such system has four phases: preprocessing, segmentation, feature extraction and classification. When digit image is scanned, quality of image is degraded and some noise is added into this image. So it is necessary to reduce the noise and improve the quality of the digit image for OCR system. For this purpose, image enhancement is necessary. For this, frequency domain based Gausian filter is used to improve the quality and denoise the digit image. The goal of image segmentation is to separate the clear digit print area from the non-digit area. After segmentation, binary digit image is skeleton to reduce the width of digit into just a single line. In proposed system, coordinates bounding box, area, centroid, eccentricity, equiv-diameter features are used by back propagation neural network as a classifier to recognize digits. Experiments have been performed on standard dataset of digits. Results of this study are quite promising and 96.6% accuracy has been achieved by the proposed system.

Design and Implementation of an FPGA-based Real-Time Face Recognition System (2011)

ABSTRACT
Face recognition systems play a vital role in many applications including surveillance, biometrics and security. In this work, we present a complete real-time face recognition system consisting of a face detection, a recognition and a downsampling module using an FPGA. Our system provides an end-to-end solution for face recognition; it receives video input from a camera, detects the locations of the face(s) using the Viola-Jones algorithm, subsequently recognizes each face using the Eigenface algorithm, and outputs the results to a display. Experimental results show that our complete face recognition system operates at 45 frames per second on a Virtex-5 FPGA

Cloud Computing

Fuzzy Keyword Search over Encrypted Data in Cloud Computing (2010)

ABSTRACT
As Cloud Computing becomes prevalent, more and more sensitive information are being centralized into the cloud. Although traditional searchable encryption schemes allow a user to securely search over encrypted data through keywords and selectively retrieve files of interest, these techniques support only exact keyword search. In this paper, for the first time we formalize and solve the problem of effective fuzzy keyword search over encrypted cloud data while maintaining keyword privacy. Fuzzy keyword search greatly enhances system usability by returning the matching files when users' searching inputs exactly match the predefined keywords or the closest possible matching files based on keyword similarity semantics, when exact match fails. In our solution, we exploit edit distance to quantify keywords similarity and develop two advanced techniques on constructing fuzzy keyword sets, which achieve optimized storage and representation overheads. We further propose a brand new symbol-based trie-traverse searching scheme, where a multi-way tree structure is built up using symbols transformed from the resulted fuzzy keyword sets. Through rigorous security analysis, we show that our proposed solution is secure and privacy-preserving, while correctly realizing the goal of fuzzy keyword search. Extensive experimental results demonstrate the efficiency of the proposed solution.

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