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In this paper, we study the problem of scheduling a set of n periodic preemptive independent hard real-time tasks on the minimum number of processors. We assume that the partitioning strategy is used to allocate the tasks to the processors and the EDF method is used to schedule the tasks on each processor. It is known that this scenario is NP-hard; thus, it is unlikely to find a polynomial time algorithm to schedule the tasks on the minimum number of processors. In this work, we derive a lower and an upper bound for the number of processors required to satisfy the constraints of our problem. We also compare a number of heuristic algorithms with each other and with the bounds derived in this paper. Numerical results demonstrate that our lower bound is very tight and it is very close to the optimal solution. [ABSTRACT FROM AUTHOR]

Let consider n autonomous mobile robots that can move in a two dimensional plane. The gathering problem is one of the most fundamental tasks of autonomous mobile robots. In short, given a set of robots with arbitrary initial locations, gathering must make all robots meet in finite time at a point that is not predefined. In this paper, we study about the feasibility of gathering by mobile robots that have φ-absolute error dynamic compasses. While the direction of each local coordinate system is fixed in usual systems, the dynamic compass model allows the angle difference between a local coordinate system and the global coordinate system to vary with time in the range of [0, φ]. This paper proposes a semi-synchronous gathering algorithm for n robots with (π/2 − ε)-absolute error dynamic compasses, where ε is an arbitrary small constant larger than zero. To the best of our knowledge, the proposed algorithm is the first one that considers both inaccurate compass models and more than two robots. We also show the optimality of our algorithm. It is proved that for any φ ≥ π/2, there is no algorithm to gather two robots with φ-absolute error dynamic compasses. [ABSTRACT FROM AUTHOR]

The digital watermark is used for detection of digital image alteration. However, most of digital images are printed on the paper document for submitting. Once digital images are printed on the paper, it is hard to detect alteration of it. In this paper, the detection method of printed image alteration by using digital watermark is proposed. [ABSTRACT FROM AUTHOR]

We investigate an automatic tuning method for an eigensolver of a dense symmetric matrix. The aim of this paper is to investigate how to select the unrolling depth. To do this, we evaluate the performance of various unrolled reduction loops of the eigensolver for every matrix size from 3000 to 4000 on the Hitachi SR8000/F1 and on the IBM RS/6000 SP3. We also analyze the trend between Byte/Flop and performance for various patterns of loop unrolling. The result shows that the performance is degraded with higher depth of unrolling in some matrix sizes, where it does not occur with lower depth of unrolling. The result also shows that selection of the unrolling depth should be examined in the case of several matrix sizes. [ABSTRACT FROM AUTHOR]

In this paper we introduce the problem of watermark security for systems in which an implementation of a watermark detector is available to an attacker. This paper serves as an introduction to a keynote talk at IWDW 2006. This talk will review two homomorphic encryption methods, viz. Paillier and Goldwasser & Micali, and their application to secure detection of Quantization Index Modulation (QIM) watermarks. [ABSTRACT FROM AUTHOR]

We demonstrate in the paper that user movement has great influences on the system performance of mobile cellular networks. We also develop a system model to study to what extent the influences will be, with focusing on the user movement simulation. We concern the parameters that determine the system performance of mobile cellular networks. We show partially in this paper that these parameters vary while user movement changes, but the effects are interactive. Since handoff calls are given a higher priority over new calls and GC mechanism is employed, our analysis shows that a mature mobile cellular network should make use of user movement characteristics and dynamically adjust its reservation threshold of the handoff call requests. Extensive simulation results validate our analysis. [ABSTRACT FROM AUTHOR]

Recently, information communication market is reorganized focused on the digital convergence service used for integrating the communication, broadcasting and internet media by connecting the communication equipment, broadcasting equipment and computer via a network. The mobility support protocol enabling the effective handover between heterogeneous networks is emerged as the hot issue in relation with these next generation communication networks. In this paper, we are to suggest the MIH Vertical handover procedure required for the implementation of MIH over MIPv4 Low-Latency vertical handover by analyzing the handover performance in the overlap area between wireless networks using the vertical handover function of MIPv4 Mobile IP Technology of IETF and considering the expected problems. Also, we are to suggest the MIH L2-Trigger generation algorithm required for deciding the optimal handoff. We evaluate the vertical handover performance of MIPv4 low-latency in the overlap area between wireless networks by using the NS-2 and applying the IEEE 802.21 MIH (Media Independent Handover) based on the suggested technique and algorithm. [ABSTRACT FROM AUTHOR]

Architecting service-oriented systems is a complex design activity. It involves making trade-offs among a number of interdependent design decisions, which are drawn from a range of concerns by various software stakeholders. In order to achieve effective and efficient SOC design we believe a careful study of architectural styles that can form the reference architecture is important. Hence, this paper provides a study of architectural styles for the reference architecture of SOC-based software systems. We propose a classification scheme for the architecture styles. These architectural styles are extracted from existing research projects and industry practices based on our classification scheme. For all those identified styles, we present an evolution trend driven by engineering principles for Internet-scale systems. As a result, this paper moves the first step towards creating a Reference Architecture that can be utilised to provide sensible guidance on the design of Web services application architecture. [ABSTRACT FROM AUTHOR]

This paper presents an efficient scheme maintaining a separator decomposition representation in dynamic trees using asymptotically optimal labels. In order to maintain the short labels, the scheme uses relatively low message complexity. In particular, if the initial dynamic tree contains just the root, then the scheme incurs an O(log3n) amortized message complexity per topology change, where n is the current number of nodes in the tree. As a separator decomposition is a fundamental decomposition of trees used extensively as a component in many static graph algorithms, our dynamic scheme for separator decomposition may be used for constructing dynamic versions to these algorithms. The paper then shows how to use our dynamic separator decomposition to construct rather efficient labeling schemes on dynamic trees, using the same message complexity as our dynamic separator scheme. Specifically, we construct efficient routing schemes on dynamic trees, for both the designer and the adversary port models, which maintain optimal labels, up to a multiplicative factor of O(loglogn). In addition, it is shown how to use our dynamic separator decomposition scheme to construct dynamic labeling schemes supporting the ancestry and NCA relations using asymptotically optimal labels, as well as to extend a known result on dynamic distance labeling schemes. [ABSTRACT FROM AUTHOR]

This paper describes an efficient scheme of probabilistic packet marking. The main idea is to preserve the victims' IP addresses at the routers participating in the packet marking scheme, based on the precondition that a router won't begin to marking until it receives a signal from the victim. Then, the destination address field of IP header can be used to carry edge information without fragmenting, and the identification field can be used to check attack paths' validity under DDoS. We describe the scheme and discuss the number of packets required for reconstructing the attack paths, the number of false positives of attackers and the extra cost at routers in this paper. [ABSTRACT FROM AUTHOR]

This paper proposes a strategy to determine how much a given network can affect the QoS parameters of another, by interference. In order to achieve this, a measurement campaign was carried out in two stages: firstly with a single AP and later with two APs separated by a distance less than three meters, using the same channel. After the measurement, an analysis of the results and a set of inferences were made by using Bayesian Networks, whose inputs were the experimental data, i.e. QoS metrics such as: throughput, jitter, packet loss, PMOS and physical metrics like power and distance. [ABSTRACT FROM AUTHOR]

The rVsAll rollback-recovery protocol assures that consistency models, called session guarantees, are provided for mobile clients and unreliable servers. The protocol is optimized according to the required consistency model by taking into account properties of session guarantees and integrating their consistency management with known rollback-recovery techniques: message-logging and checkpointing. We have proved the correctness of rVsAll protocol in terms of safety and liveness properties. These properties assert that clients access object replicas maintained by servers according to the required session guarantee regardless of server's failures, and state that each access operation issued by clients will eventually be performed (in a finite time), even in the presence of server's failures. In this paper, we show that the proposed protocol is also optimal, in the sense that, the consistent global checkpoint taken in rVsAll protocol contains the minimal number of operations indispensable to fulfill the required session guarantees after server's failure and its recovery. The paper presents the proof of the optimality property of the proposed protocol. [ABSTRACT FROM AUTHOR]

Network-on-Chip is an alternative paradigm to improve communication bandwidth compared to bus-based communication, and its performance degrades if there is no effective flow control method., Heterogeneous networks with very slow processing elements (PEs) especially need a flow control mechanism at the transport layer to prevent too much packet injection. In this paper, a credit-based end-to-end flow control (CB-EEFC) is implemented to control the network latency at high traffic loads. Simulation in mesh networks shows improved performance in latency and 0.5% up to 3% saturated throughput decrease with the CB-EEFC method. RTL gate level simulation shows that a network interface using CB-EEFC brings about a 31.4% increase in complexity compared to a network interface without CB-EEFC. [ABSTRACT FROM AUTHOR]

This paper focuses on parallel interactive applications ranging from scientific visualization, to virtual reality or computational steering. Interactivity makes them particular on three main aspects: they are endlessly iterative, use advanced I/O devices, and must perform under strong performance constraints (latency, refresh rate). In this paper, we propose an application description language based on a data flow and hierarchical component model to cope with the complexity of parallel interactive applications. It enables us to define highly generic components, enforcing the application maintainability and portability. An implementation on top of the FlowVR middleware is presented. [ABSTRACT FROM AUTHOR]

In this paper a high performance storage system for RDF documents is introduced. The system employs optimized index structures for RDF data and efficient RDF query evaluation. The index scheme consists of 3 types of indices. Triple index manages basic RDF triples by dividing original RDF graph into several sub-graphs. Path index manages frequent RDF path patterns for long path query performance enhancement. Context index is optional for context oriented RDF data and temporal RDF data. In this paper, we describe the organization of index structures, show the process of evaluating queries based on the index structures, and provide a performance comparison with exist RDF databases through several benchmark experiments. [ABSTRACT FROM AUTHOR]

To fulfill the application of wireless network in small area, this paper proposed a protocol for decentralized all-connected wireless network. This protocol is based on DS-CDMA with the ability of multi-user detection (MUD). And it has the characteristics of transmitting data in parallel, high network throughput and low communication error rate. In this paper, the process of the protocol is introduced, and an improved quasi-synchronous decorrelation multi-user detection algorithm is deduced in detail. And then, the protocol is simulated and the results are analyzed. [ABSTRACT FROM AUTHOR]

Multi-log2N networks architecture is attractive for constructing optical switches, and the related routing algorithms are critical for the operation and efficiency of such switches. Although several routing algorithms have been proposed for multi-log2N networks, a full performance comparison among them is not available by now. Thus, this paper is committed to such a comparison in terms of blocking probability, time complexity, hardware cost and load balancing capability. Notice that the load balance is important for reducing the peak power requirement of a switch, so we also propose in this paper two new routing algorithms for optical multi-log2N networks to achieve a better load balance. [ABSTRACT FROM AUTHOR]

Differential uniformity is an important property of cryptographic building blocks used in the design of symmetric ciphers. In this paper it is proved that certain canonical mappings on elliptic curves are differentially uniform. The main observation of this paper is that the impersonation attack against the implicit certificate scheme of Ateniese and de Medeiros does not work if a differentially uniform mapping is used in the scheme. This phenomenon is analyzed in the slightly more general context of a partially blind signature scheme, which is a new cryptographic primitive that seems to gain security properties from differentially uniform mappings. [ABSTRACT FROM AUTHOR]

Program obfuscation is a semantic-preserving transformation aimed at bringing a program into such a form, which impedes the understanding of its algorithm and data structures or prevents extracting of some valuable information from the text of a program. Since obfuscation could find wide use in computer security, information hiding and cryptography, security requirements to program obfuscators became a major focus of interests for pioneers of theory of software obfuscation. In this paper we also address the issue of defining security of program obfuscation. We argue that requirements to obfuscation may be different and dependent on potential applications. Therefore, it makes sense to deal with a broad spectrum of security definitions for program obfuscation. In this paper we analyze five models for studying various aspects of obfuscation: "black box" model of total obfuscation, "grey box" model of total obfuscation, obfuscation for software protection, constant hiding, and predicate obfuscation. For each of these models we consider the applications where the model may be valid, positive and negative results on the existence of secure obfuscation in the framework of the model, and relationships with other models of program obfuscation. [ABSTRACT FROM AUTHOR]

NLS is a stream cipher which was submitted to the eSTREAM project. A linear distinguishing attack against NLS was presented by Cho and Pieprzyk, which was called Crossword Puzzle (CP) attack. NLSv2 is a tweak version of NLS which aims mainly at avoiding the CP attack. In this paper, a new distinguishing attack against NLSv2 is presented. The attack exploits high correlation amongst neighboring bits of the cipher. The paper first shows that the modular addition preserves pairwise correlations as demonstrated by existence of linear approximations with large biases. Next, it shows how to combine these results with the existence of high correlation between bits 29 and 30 of the S-box to obtain a distinguisher whose bias is around 2− 37. Consequently, we claim that NLSv2 is distinguishable from a random cipher after observing around 274 keystream words. [ABSTRACT FROM AUTHOR]

The paper considers broadcasting protocols in radio networks with known topology that are efficient in both time and energy. The radio network is modelled as an undirected graph G = (V,E) where V = n. It is assumed that during execution of the communication task every node in V is allowed to transmit at most once. Under this assumption it is shown that any radio broadcast protocol requires $D+\Omega(\sqrt{n-D})$ transmission rounds, where D is the diameter of G. This lower bound is complemented with an efficient construction of a deterministic protocol that accomplishes broadcasting in $D+O(\sqrt{n}\log n)$ rounds. Moreover, if we allow each node to transmit at most k times, the lower bound D + Ω((n − D)1/(2k)) on the number of transmission rounds holds. We also provide a randomised protocol that accomplishes broadcasting in D + O(kn1/(k − 2)log2n) rounds. The paper concludes with a discussion of several other strategies for energy efficient radio broadcasting and a number of open problems in the area. [ABSTRACT FROM AUTHOR]

Consider a network whose inputs change rapidly, or are subject to frequent faults. This is expected often to be the case in the foreseen huge sensor networks. Suppose, that an algorithm is required to output the majority value of the inputs. To address such networks, it is desirable to be able to stabilize the output fast, and to give guarantees on the outputs even before stabilization, even if additional changes occur. We bound the instability of the outputs (the number of times the output changes) of majority consensus algorithms even before the final stabilization. We show that the instability can be traded off with their time adaptvity (how fast they are required to stabilize the output if f faults occurred). First, for the extreme point of the trade-off, we achieve instability that is optimal for the class of algorithms that are optimal in their output time adaptivity. This is done for various known versions of majority consensus problem. The optimal instability for this case is Ω(logf) and is shown to be O(logf) for most versions and O(logn) in some cases. Previous such algorithms did not have such a guarantee on the behaviour of the output before its final stabilization (and their instability was Ω(n)). We also explain how to adapt the results for other points in the trade off. The output stabilization in previous algorithms was adaptive only if the faults ceased for O(Diam) time. An additional result in this paper uses adaptations of some previous tools, as well as the new tools developed here for bounding the instability, in order to remove this limitation that is undesirable when changes are frequent. [ABSTRACT FROM AUTHOR]

We study the impact of faulty processors on the communication cost of distributed algorithms in a message-passing model. The system is synchronous but prone to various kinds of processor failures: crashes, message omissions, (authenticated) Byzantine faults. One of the basic communication tasks, called fault-tolerant gossip, or gossip for short, is to exchange the initial values among all non-faulty processors. In this paper we address the question if there is a gossip algorithm which is both fault-tolerant, fast and communication-efficient? We answer this question in affirmative in the model allowing only crash failures, and in some sense negatively when the other kinds of failures may occur. More precisely, in an execution by n processors when f of them are faulty, each non-faulty processor contributes a constant to the message complexity, each crashed processor contributes Θ(fε) (ε> 0 could be an arbitrarily small constant independent from n,f but dependent on the algorithm), each omission (or authenticated Byzantine) processor contributes Θ(t), and each—even potential—Byzantine failure results in additional Θ(n) messages sent. [ABSTRACT FROM AUTHOR]

This paper shows experimental results of the linear algebra step in the number field sieve on parallel environment with implementation techniques. We developed an efficient algorithm that shares the sum of vectors in each node, and the network structure among the nodes only requires to include a ring. We also investigated the construction of a network for the linear algebra step. The construction can be realized through switches and network interface cards, whose prices are not expensive. Moreover, we investigated the implementation of the linear algebra step using various parameters. The implementation described in this paper was used for the integer factoring of a 176 digit number by GNFS and a 274 digit number by SNFS. [ABSTRACT FROM AUTHOR]

Transforming private-key encryption schemes into public-key encryption schemes is an interesting application of program obfuscation. The idea is that, given a private-key encryption scheme, an obfuscation of an encryption program with a private key embedded is used as a public key and the private key is used for decryption as it is. The security of the resulting public-key encryption scheme would be ensured because obfuscation is unintelligible and the public key is expected to leak no information on the private key. This paper investigates the possibility of general-purpose obfuscators for such a transformation, i.e., obfuscators that can transform an arbitrary private-key encryption scheme into a secure public-key encryption scheme. Barak et al. have shown a negative result, which says that there is a deterministic private-key encryption scheme that is unobfuscatable in the sense that, given any encryption program with a private key embedded, one can efficiently compute the private key. However, it is an open problem whether their result extends to probabilistic encryption schemes, where we should consider a relaxed notion of obfuscators, i.e., sampling obfuscators. Programs obfuscated by sampling obfuscators do not necessarily compute the same function as the original program, but produce the same distribution as the original program. In this paper, we show that there is a probabilistic private-key encryption scheme that can not be transformed into a secure public-key encryption scheme by sampling obfuscators which have a special property regarding input-output dependency of encryption programs. Our intention is not to claim that the required special property is reasonable. Rather, we claim that general-purpose obfuscators for the transformation, if they exist, must be a sampling obfuscator which does NOT have the special property. [ABSTRACT FROM AUTHOR]

This paper presents a Colored Petri Nets (CPN) approach to analyze the information flow in the policy file of Security-Enhanced Linux (SELinux). The SELinux access control decisions are based on a security policy file that contains several thousands of security rules. It becomes a challenge for policy administrator to determine whether the modification of the security policy file conforms to the pre-specified security goals. To address this issue, this paper proposes a formal information flow model for SELinux security policy file, and presents a simple query language to help administrators to express the expected/unexpected information flow. We developed a method to transform the SELinux policy and security goal into Policy CPN Diagram and Query CPN Diagram. A tool named SEAnalyzer that can automatically verify the SELinux policy has been developed and two application examples of this tool will be presented in the context. Keywords: Colored Petri Nets, information flow, SELinux, security policy. [ABSTRACT FROM AUTHOR]

This position paper discusses the relation of privacy, namely pseudonymity, to evidence-based trust (or rather reputation). Critical concepts of evidence-based trust/reputation systems are outlined first, followed by an introduction to the four families of the Common Criteria (for security evaluation) Privacy Class: Unobservability, Anonymity, Unlinkability, and Pseudonymity. The paper then discusses the common problem of many papers that narrow the considerations of privacy to anonymity only, and elaborates on the concept of pseudonymity through aspects of evidence storing, attacks and some of their implications, together with other related issues like use of mixes. [ABSTRACT FROM AUTHOR]

In this paper, we present a security framework that provides identity protection against active and passive attacks for end-points. The framework is based on a two-round-trip authenticated Diffie-Hellman key exchange protocol that identifies the end-points to each other and creates a security association between the peers. The protocol hides the public key based identifiers from attackers and eavesdroppers by blinding the identifiers. We complete the identity protection by offering location privacy with forwarding agents. To our knowledge, our privacy enhanced protocol is the first denial-of-service resistant two-round-trip key exchange protocol that offers identity protection for both communicating peers. [ABSTRACT FROM AUTHOR]

In keeping with the tradition of this workshop this is actually a position paper in the sense that it represents work that's not done and ideas for work that could be done, rather than simply a paper that got rejected from a bunch of other conferences. [Laughter] [ABSTRACT FROM AUTHOR]

This paper identifies certain privacy threats that apply to anonymous credential systems. The focus is on timing attacks that apply even if the system is cryptographically secure. The paper provides some simple heuristics that aim to mitigate the exposure to the threats and identifies directions for further research. Keywords: anonymous credential systems, pseudonym systems, unlinkability, privacy, timing attacks. [ABSTRACT FROM AUTHOR]

Cheating in secret sharing has been considered in several papers. Recently cheating in visual cryptography has been considered in [10], where (2,n)-threshold visual cryptography schemes are provided. In this paper we provide new (2,n)-threshold visual cryptography schemes. Our model is different from the one considered in [10]; in particular we aim at constructing cheating immune schemes without the use of extra information, like additional shares or images as done in [10]. We have provided a formal definition of cheating which requires that a group of cheaters be able to deterministically force a honest participant to reconstruct a wrong secret. The (2,n)-threshold schemes that we provide do not allow such cheating, regardless of the number of cheaters. [ABSTRACT FROM AUTHOR]

The main goal of this paper is to generalize the results, obtained in [1] to the case of quasi-linear ordinary differential equations of the second order with the third kind boundary conditions. It is a continuation of the paper series in which we have obtained weight a priori estimates of accuracy for difference schemes for linear parabolic type equations in one-dimensional [2] and two-dimensional [3] cases, quasi-linear parabolic type equations [4] and quasi-linear elliptic equations with conditions of the first kind [5]. In this paper it is shown that on approaching to the left or right boundary of the domain the rate of convergence of solution or it's first derivative, correspondingly, increases. The second accuracy order difference scheme of the special form has been used for this purpose. The paper is completed by numerical experiment, which results confirm theoretical statements. [ABSTRACT FROM AUTHOR]

In this paper, we investigate several data reduction schemes to improve the computational efficiency in the multi reference configuration interaction (MR-CI) method, one of the main quantum chemical approaches for solving the electronic Schrödinger equation. The basic idea is to take advantage of the often relatively low accuracy requirements on the solution of the resulting large eigenvalue problem, whose dimension may reach several hundred millions or even more. We will discuss some approaches to reduce the amount of data to be accessed and to be transferred within the Davidson subspace diagonalization method. We also show experimental results achieved with the COLUMBUS code. [ABSTRACT FROM AUTHOR]

Grid computing is a form of distributed computing that involves coordinating and sharing computing, application, data storage or network resources across dynamic and geographically dispersed organizations. The goal of grid task scheduling is to achieve high system throughput and to match the application needed with the available computing resources. This is matching of resources in a non-deterministically shared heterogeneous environment. The complexity of scheduling problem increases with the size of the grid and becomes highly difficult to solve effectively. To obtain good methods to solve this problem a new area of research is implemented. This area is based on developed heuristic techniques that provide an optimal or near optimal solution for large grids. In this paper we introduce a tasks scheduling algorithm for grid computing. The algorithm is based on Ant Colony Optimization (ACO) which is a Monte Carlo method. The paper shows how to search for the best tasks scheduling for grid computing. [ABSTRACT FROM AUTHOR]

Receipt-freeness is the property of voting protocols that a voter cannot create a receipt which proves how she voted. Since Benaloh and Tuinstra introduced this property, there has been a large amount of work devoted to the construction of receipt-free voting protocols. This paper provides a generic and uniform formalism that captures the notion of a receipt. The formalism is then applied to analyse the receipt-freeness of a number of voting protocols. Keywords: online voting schemes, receipt-freeness, formal methods, eGovernment. [ABSTRACT FROM AUTHOR]

The paper considers the software simulation tool DDoSSim which has been developed for comprehensive investigation of Internet DDoS attacks and defense mechanisms. This tool can be characterized by three main peculiarities: agent-oriented approach to simulation, packet-based imitation of network security processes, and open library of different DDoS attacks and defense mechanisms. DDoSSim allows deeply investigating various attacks and defense methods and generating valuable recommendations on choosing the best defense. In the paper the agent-oriented approach suggested is considered. The taxonomy of input and output parameters for simulation is outlined. The main DDoSSim components are specified. One of the experiments on protection against DDoS attacks demonstrates some DDoSSim possibilities. We consider different phases of defense operations - learning, decision making and protection, including adaptation to the actions of malefactors. Keywords: Security modeling and architecture, Security models for ambient intelligence environments, Infrastructure security, Security simulation, DDoS. [ABSTRACT FROM AUTHOR]

The lingua franca of a market-based resource allocation infrastructure is the credit transfer protocol. The protocol design determines the expressible access-control policies and the supported trading patterns. This paper presents a protocol supporting fine grained manipulation of ownership authorities for enhanced expressiveness. [ABSTRACT FROM AUTHOR]

Image splicing is a commonly used technique in image tampering. This paper presents a novel approach to passive detection of image splicing. In the proposed scheme, the image splicing detection problem is tackled as a twoclass classification problem under the pattern recognition framework. Considering the high non-linearity and non-stationarity nature of image splicing operation, a recently developed Hilbert-Huang transform (HHT) is utilized to generate features for classification. Furthermore, a well established statistical natural image model based on moments of characteristic functions with wavelet decomposition is employed to distinguish the spliced images from the authentic images. We use support vector machine (SVM) as the classifier. The initial experimental results demonstrate that the proposed scheme outperforms the prior arts. Keywords: image splicing, Hilbert-Huang transform (HHT), characteristic functions, support vector machine (SVM). [ABSTRACT FROM AUTHOR]

This paper addresses a novel steganography method for images. Most statistical steganalysis algorithms are strong to defeat previous steganography algorithms. RS steganalysis and pixel difference histogram analysis are two well-known statistical steganalysis algorithms which detect non-random changes caused by embedding a secret message into cover image. In this paper, we first explain how two steganalysis algorithms exploit the effect of the non-random changes and then propose a new steganography method that avoids the non-random changes to evade statistical analysis methods. For this purpose, we adjust the embedding process to be more adaptive to cover image by considering embedding in Gray code bit planes, not natural binary bit planes, of cover images, and two parameters: (1) similarity threshold for selecting non-flat area in lower bit planes, and (2) size of flat blocks n×n in embedding bit planes. Experimental results show that the secret messages embedded by our method are undetectable under RS steganalysis and pixel difference histogram analysis. [ABSTRACT FROM AUTHOR]

Clusters typically represent a homogeneous, well maintained pool of high-end computation resources. This makes them particularly attractive for volunteer computing, where unused compute cycles are utilized for scientific guest applications. Cluster nodes are not idle as often as public PCs, but they are frequently underutilized while actively executing parallel applications. Hence, fully exploiting clusters for volunteer computing requires the ability to efficiently and invisibly steal the unused cycles at a fine grain from the currently running host applications, without slowing them down. In this paper we present measurements on a production compute cluster that show long periods of CPU and memory underutilization patterns that could be used to execute guest applications. In our experiments with NAS benchmarks on a small Linux cluster, cycle stealing led to a 3.6% average slowdown of host applications in the best case. This was accompanied by an overall improvement in the system throughput of 38%, when progress of the guest applications was included. We introduce simple guidelines on using clusters for volunteer computing. We also argue for the support of "zero priority" processes in OS schedulers which could virtually eliminate the impact of volunteer computing on host applications. [ABSTRACT FROM AUTHOR]

Advance reservation of resources has been suggested as a means to provide a certain level of support that meets user expectations with respect to specific job start times in parallel systems. Those expectations may relate to a single job application or an application that consists of a collection of dependent jobs. In the context of Grid computing, applications consisting of dependent tasks become increasingly important, usually known as workflows. This paper focuses on the problem of planning advance reservations for individual tasks of workflow-type of applications when the user specifies a requirement only for the whole workflow application. Two policies to automate advance reservation planning for individual tasks efficiently are presented and evaluated. [ABSTRACT FROM AUTHOR]

The performance of event-driven network applications, such as Web servers and proxies, was influenced by the scalability and efficiency of synchronous I/O multiplexing mechanism. Research shows that event-based mechanism can ensure the scalability, and using kernel-user shared memory to evade system calls can reduce a lot of system overhead. But these two features can not be combined by any solution till now, because of synchronous problem. This paper attempts to design an event notification mechanism for event-driven network applications, which using kernel-user shared event queues (KSEQ) to achieve both good scalability and low system overhead. The KSEQ works something like double buffer, and both application and kernel can write the shared data structures without the help of synchronization system calls. Experiment shows that the Squid proxy server using this mechanism presents shorter response time than other mechanisms. [ABSTRACT FROM AUTHOR]

This paper proposes a novel resource management framework that integrates Call Admission Control (CAC) and aggregate reservation of bandwidth for mobile networks in a scalable fashion. Our proposal avoids per-user reservation signaling overhead and takes into account the expected bandwidth to be used by calls handed off from neighboring cells within a prediction interval through the Trigg and Leach Method (an adaptive exponential smoothing technique). Our scheme is compared through simulations with the ACR (Adaptive Channel Reservation) scheme, a dynamic reservation-based proposal that uses GPS systems to extrapolate users' movement and to trigger reservations in the next predicted cell. The simulation results show that our proposal provides the best performance in terms of handoff dropping probability and can achieve similar levels of call blocking probability as compared to ACR. In addition, our proposal can grant an upper bound on handoff dropping probability even under very high loads. [ABSTRACT FROM AUTHOR]

This paper addresses the issue of multicast communication in scalable interconnection networks, using path-based scheme. Most existing multicast algorithms either assume a fixed network size, low dimensional networks or only consider the latency at the network level. As a consequence, most of these algorithms implement multicast in a sequential manner and can not scale well with the network dimensions or the number of nodes involved. Furthermore, most of these algorithms handle multicast communication with low throughput. In this paper, we propose a multicast algorithm for multidimensional interconnection networks, which is built upon our Qualified Groups QG multicast scheme for ensuring efficient communication irrespective of the network sizes/dimensions or the number of the destination nodes. Unlike the existing works, this study considers the scalability and latency at both the network and node levels so as to achieve a high degree of parallelism. Our results show that the proposed algorithm considerably improves the multicast message delivery ratio, throughput and scalability. [ABSTRACT FROM AUTHOR]

In this paper, we apply the hierarchical concept to the Care-of Prefix (CoP) scheme as HCoP and enhance HCoP with a novel Binding Update Tree (BUT) structure as HCoP-B for NEtwork MObility (NEMO) management of the nested mobile network. As compared to schemes such as Reverse Routing Header (RRH), Route Optimization using Tree Information Option (ROTIO) and HCoP with numerical performance evaluations, HCoP-B achieves the shortest handoff latency and significantly reduces the consumed network bandwidth of global binding update messages for route optimizations (RO) of all correspondent nodes (CN) after the nested mobile network hands over to a new AR. Consequently, HCoP-B resolves the RO storm problem. [ABSTRACT FROM AUTHOR]

Multiple non-overlapped channels are available in IEEE 802.11 but are rarely used today in wireless multi-hop networks. Wireless mesh network is a special type of multi-hop ad hoc network and is envisioned to provide high capacity and large coverage. In this paper, we propose a 2-hop clustering based multi-interface, multi-channel network architecture and design a novel channel assignment algorithm and routing metric. Channel assignment is composed of Inter-cluster Static Assignment and Intra-cluster Dynamic Assignment. Since traditional routing metrics, such as hop-count, may not perform well in multi-channel wireless networks, we propose the CDM routing metric, which combines hop-count, channel diversity and channel switching capability together. Simulation results show that our algorithms achieve up to 3.3 times higher end-to-end throughput. [ABSTRACT FROM AUTHOR]

Mobile SCTP (mSCTP) has been proposed to support transport layer mobility management. In this paper, we proposed a dynamic handover mechanism named Contention-based mSCTP (C-mSCTP) in the contention based wireless network. The handover strategy in C-mSCTP takes wireless bandwidth and the contention probability into account to set the primary path before transmitting data. The simulation results show that the C-mSCTP achieves much better performance in terms of transmission delay and throughput than mSCTP does. [ABSTRACT FROM AUTHOR]

IPv4 architecture is well entrenched with Network Address Translation (NAT) boxes, which cause well-known problems for Peer-to-Peer (P2P) applications. IPv6 would enable end-to-end connectivity when deployed, but the industry has been slow in transitioning to IPv6. IPv4+4 has been suggested as an alternative NAT-extended addressing architecture, where the idea is to assign 64-bit end-to-end globally unique addresses for nodes on private address realms by concatenating the 32-bit globally routable IPv4 address of the realm (border) gateway with the 32-bit private IPv4 addresses of the nodes. While IPv4+4 addressing proposal is neat, existing IPv4+4 implementations require changes to all border gateways and end-hosts, which hinders its deployment. In this paper we show how the IPv4+4 addressing architecture can be implemented by using a modified version of the standard IPv4 Loose Source Record Route (LSRR) option. Our proposal requires no changes to existing IPv4 infrastructure (assuming all IPv4-compliant nodes implement LSRR as required by RFC 791), thus enabling seamless end-to-end communication for P2P applications. We demonstrate packet forwarding with the 64-bit IPv4+4 addresses, and illustrate how the widely-used P2P voice over IP protocol, the Session Initiation Protocol, can make use of our proposal for seamless end-to-end communication. [ABSTRACT FROM AUTHOR]

In WDM mesh networks, low-speed data streams from individual users are combined, using the techniques of traffic grooming, for efficient utilization of the high bandwidth of a lightpath. The objective of traffic grooming is to minimize the cost of the network and/or to maximize the network throughput. Proposed solutions for this optimization problem are computationally intractable, even for networks of moderate size. In this paper, we have presented efficient Integer Linear Program (ILP) formulations for traffic grooming on mesh WDM networks, one for minimizing the congestion and the other to maximize the throughput of the network, with an assumption that the logical topology is specified. Unlike previous formulations, our formulations can be used for practical sized networks. We have simulated our formulations with networks up to 30 nodes, and with hundreds and even thousands of low-speed data streams and have shown that the formulations are able to generate optimal solutions within a reasonable amount of time. [ABSTRACT FROM AUTHOR]

By means of analysis and generalization of the hypercube and its variations of the same topological properties and network parameters, a family of interconnection networks, referred to as binary recursive networks, is introduced in this paper. This kind of networks not only provides a powerful method to investigate the hypercube and its variations on the whole, but also puts forth an effective tool to explore new network structures. A constructive proof is presented to show that binary recursive networks are Hamiltonian based on their recursive structures, and an approach to prove 4-pancyclicity of a subfamily of binary recursive networks is outlined. [ABSTRACT FROM AUTHOR]