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In the current research on data query for two-tiered WSN, the privacy-preservation range query is one of the hotspots. However, there are some problems in the existing researches in two-tiered wireless sensor networks such as high computational and communication costs for security comparison items and high energy consumption of sensing nodes. In this paper, a privacy-preservation range query protocol based on the integration reversal 0-1 encoding with Bloom filter is researched and designed. In the sensing data submission stage, the optimized reversal 0-1 encoding, HMAC algorithm, AES encryption algorithm and variable-length Bloom filter are used for generating the maximum–minimum comparison encoding and constructing a shorter verification index chain to reduce computational and communication costs of sensing nodes; in the private data range query stage, the base station uses the HMAC algorithm to convert the plaintext query range into the ciphertext query range and sends it to the storage node. In the storage node, the bitmap encoding information of the verification index chain is calculated with the comparison rule of the reversal 0-1 encoding and it is returned to the base station together with the verification index chain and the data ciphertext that compliance with the query rule; in the data integrity verification stage, the integrity of the query results using the verification index chain and bitmap encoding is verified at the base station. In the experimental section, the Cortex-M4 development board equipped with the Alios-Things operating system as sensing node and the Cortex-A9 development board equipped with the Linux operating system as storage node are implemented in this protocol, which is compared with the existing protocols in three aspects: the number of data collected in each cycle, the length of data and the number of data dimensions. The experimental results show that the energy consumption of this protocol is lower under the same experimental environment. [ABSTRACT FROM AUTHOR]

Link failures are commonly observed in computer networks, including the newly emerging Software Defined Network (SDN). Considering that failure recovery methods used in traditional networks cannot be applied to SDN networks directly, we propose a method named pro-VLAN in this paper, which calculates a backup path and assigns a unique VLAN id for each link of the network based on the protection mechanism. It makes the most of SDN's features and can recover a single link failure in SDN with the advantages of high efficiency, strong scalability and wide applicability. More specifically, high efficiency (i.e., a fast failure recovery with a low memory consumption) is achieved by calculating backup paths for each link instead of each flow and using group tables to switch backup paths automatically and locally when failures occur. Strong scalability (i.e., the amount of backup flow entries per switch is stable) is achieved by keeping the amount of links per switch no matter how the network scale extends or how the amount of flows increases. Wide applicability is achieved by always finding a path available without modifying any hardware or protocol as long as the network is still reachable after a link failure. Simulation results and mathematical analysis demonstrate that both pro-VLAN and a flow-based protection method achieve a fast failure recovery, while pro-VLAN consumes less than 1% of the forwarding entries to store backup paths as compared to the flow-based method. Moreover, when the network scale increases from 10 to 60 switches by 500%, the increase of the number of backup flow entries per switch built by pro-VLAN is only less than 50%. [ABSTRACT FROM AUTHOR]

Internet of Things (IoTs) are becoming one of the integral parts of our lives, as all of the modern devices including pervasive systems use internet for its connectivity with the rest of the world. The Radio Frequency IDentification (RFID) provides unique identification and nonline of sight capabilities, therefore plays a very important role in development of IoTs. However, the RFID systems incorporate wireless channel for communication, therefore have some allied risks to the system from threat agents. In order to prevent the system from malicious activities in a cost effective way, numerous Ultralightweight Mutual Authentication Protocols (UMAPs) have been proposed since last decade. These UMAPs mainly involve simple bitwise logical operators such as XOR, AND, OR, etc., in their designs and can be implemented with extremely low cost RFID tags. However, most of the UMAP designers didn't provide the proper hardware approximations of their UMAPs and presented only theoretical results which mostly mislead the reader. In this paper, we have addressed this problem by reporting our experiences with FPGA and ASIC-based implementation of UMAP named psuedo Kasami code-based Mutual Authentication Protocol (KMAP. Further, we have also improved the structure of the KMAP protocol to overcome the previously highlighted attack model. The hardware implementation results show that KMAP successfully conform to EPC-C1G2 tags and can be implemented using less than 4K GE (for 32-bit word length). [ABSTRACT FROM AUTHOR]

The response time for multi-tenant queries is one of the most important indicators in the service level agreements (SLA). The service provider tries to optimize query scheduling strategy to finish queries of different tenants before the deadline to avoid penalty due to jeopardizing the SLA. With continuous expansion of tenants scale, peer-to-peer (P2P) structure becomes more and more popular in organizing and managing multi-tenant data. In this paper we propose an acentric scheduling approach for SLA-based multi-tenant queries according to the distribution characteristics of multi-tenant data. Our scheduling approach deploys multiple scheduling engines on the computing nodes in the cloud, where the computing node of each engine schedules its assigned queries, estimates whether these queries could be finished before the deadline, and migrates the queries that might jeopardize the SLA to another engine which can respond to it before the deadline. Since the high efficiency of the scheduling process is critical, we improve the balanced binary tree and use it to organize queries on each computing node. Using this structure, the online time complexity of the scheduling strategy is . Our extensive experiments demonstrate that our scheduling strategy is sufficient to meet the high scheduling efficiency requirement, while the penalty cost can be reduced up to compared with the benchmarking solution and with a better scalability. [ABSTRACT FROM AUTHOR]

In this paper, we present a simple permission-based fair stabilizing solution to the - exclusion problem in tree networks. The -exclusion problem is a generalization of the mutual exclusion problem where processes, instead of 1, are allowed to use a shared resource (enter the critical section) simultaneously. The proposed algorithm is optimal in terms of waiting times of processes to enter critical sections, i.e., between two entries of a process to its critical section, no other process can enter its critical section more than once after stabilization. Since our algorithm is stabilizing, it does not require initialization and withstands transient faults. The stabilization time of the algorithm is rounds and the waiting time is , where h and n are the height and the size of the tree, respectively. In addition, this algorithm satisfies all the requirements of the -exclusion problem: and liveness. [ABSTRACT FROM AUTHOR]

Large scale synchronous network-on-chip (NoC) requires complex clock tree design, which leads to a large area overhead and power consumption. Based on handshaking protocols, asynchronous NoC does not have global clock tree distribution, which results in a natural power saving mode without any explicit clock gating. However, the faults occurring in such asynchronous networks will seriously affect their performances. In this paper, we propose AFTER, an Asynchronous Fault-TolErant Router, which uses the quasi delay insensitive (QDI) logic. The proposed router is able to detect the faults of ports and links. Then, a fault-tolerant routing mechanism, based on the port priority in different quadrants, is proposed to maximize the number of packets that can be transmitted via the shortest paths. In this way, the fault-tolerance of asynchronous routers can be achieved. Besides that, AFTER could also achieve high scalability, and is suitable for the large scale globally asynchronous locally synchronous (GALS) system. The experimental results show that, when faults occur in the network, AFTER has a better fault-tolerance performance than the reference. [ABSTRACT FROM AUTHOR]

Protocol's abnormal behavior analysis is an important task in protocol reverse analysis. Traditional protocol reverse analysis focus on the protocol message format, but protocol behavior especially the abnormal behavior is rare studied. In this paper, protocol behavior is represented by the labeled behavior instruction sequences. Similar behavior instruction sequences mean the similar protocol behavior. Using our developed virtual analysis platform HiddenDisc, we can capture a variety of known or unknown protocols' behavior instruction sequences. All kinds of executed or unexecuted instruction sequences can automatic clustering by our designed instruction clustering algorithm. Thereby we can distinguish and mine the unknown protocols' potential abnormal behavior. The mined potential abnormal behavior instruction sequences are executed, monitored and analyzed on HiddenDisc to determine whether it is an abnormal behavior and what is the behavior's nature. Using the instruction clustering algorithm, we have analyzed 1297 protocol samples, mined 193 potential abnormal instruction sequences, and determined 187 malicious abnormal behaviors by regression testing. Experimental results show that our proposed instruction clustering algorithm has high efficiency and accuracy, can mine unknown protocols' abnormal behaviors effectively, and enhance the initiative defense capability of network security. [ABSTRACT FROM AUTHOR]

Wi-Fi protected access (WPA) has provided serious improvements over the now deprecated wired equivalent privacy (WEP) protocol. WPA, however, still has some flaws that allow an attacker to obtain the passphrase. One of these flaws is exposed when the access point (AP) is operating in the WPA personal mode. This is the most common mode, as it is the quickest and easiest to configure. This vulnerability requires the attacker to capture the traffic from the four-way handshake between the AP and client, and then have enough compute time to reverse the passphrase. Increasing the rate at which passphrases can be reversed reduces the amount of time required to construct a repository of service set identifiers (SSIDs) and passphrases, which can increase the chances an attack is successful, or, alternatively, reduce the difficulty of auditing a wireless network for security purposes. This work focuses on creating an field programmable gate array (FPGA)-based architecture to accelerate the generation of a WPA/WPA2 pairwise master key (PMK) lookup table (LUT) for the recovery of the passphrase, with special emphasis on the secure hash algorithm-1 (SHA-1) implementation. PMK generation relies heavily on SHA-1 hashing and, as this work shows, an optimized SHA-1 implementation can achieve up to a 40 × speedup over an unoptimized implementation when generating PMKs. [ABSTRACT FROM AUTHOR]

Embedded distributed multimedia applications based on the use of on-chip networks for communication and messages exchange requires specific and enhanced quality of service (QoS) management. To reach the desired performances at the application level, the network-on-chip (NoC) router should implement per flit handling strategy with wide granularity. This purpose requires an enhanced internal architecture that ensures from one hand a specific management according to a service classification and from the other hand, it enhances the routing process. In this context, this paper proposes a new mechanism for QoS management in NoC. This mechanism is based on the use of central memory where flits are in-queued according to their class of service. This scheme enables an optimal flit scheduling phase and provides more capabilities to drop low important flits when the router shows congestion state symptoms. The paper presents, also, a protocol structure that fills with this architecture and introduces a signaling mechanism to make efficient the QoS management through the proposed architecture. The circuit performances and its adaptability to achieve QoS with low power processing and high bandwidth in on chip multiprocessor systems will be studied in this paper. [ABSTRACT FROM AUTHOR]

To reduce the running time of network simulation in heterogeneous computing environment, a network simulation task partition method, named LBPHCE, is put forward. In this method, the network simulation task is partitioned in comprehensive consideration of the load balance of both routing computing simulation and packet forwarding simulation. First, through benchmark experiments, the computation ability and routing simulation ability of each simulation machine are measured in the heterogeneous computing environment. Second, based on the computation ability of each simulation machine, the network simulation task is initially partitioned to meet the load balance of packet forwarding simulation in the heterogeneous computing environment, and then according to the routing computation ability, the scale of each partition is fine-tuned to satisfy the balance of the routing computing simulation, meanwhile the load balance of packet forwarding simulation is guaranteed. Experiments based on PDNS indicate that, compared to traditional uniform partition method, the LBPHCE method can reduce the total simulation running time by 26.3% in average, and compared to the liner partition method, it can reduce the running time by 18.3% in average. [ABSTRACT FROM AUTHOR]

Productivity is a key element in organizational management. Although it can be measured at different levels (country, sector, organization ...) this research focuses on productivity at the job level. The aim of this paper is to obtain an overview of the state of the art in productivity measurement in software engineering, including the inputs and outputs of the production process used for this measurement at the job level in the workplace. To do so, a systematic literature review protocol was adapted from literature review protocol standards, and subsequently carried out. The objective is to assess the current inputs and outputs present in the literature in order to create new productivity measures for software practitioners. This paper reveals that two different measures are used to assess software engineering professionals: traditional SLOC/Time and planning projects units per time unit. [ABSTRACT FROM AUTHOR]

We present a study of the effects of active queue management (AQM) on the average queue size in routers. In this work, three prominent AQM schemes are considered: packet classification, checking service level agreements (SLA) and queue scheduling. This paper presents several adaptive resource sharing models that use a revenue criterion to allocate bandwidth in an optimal way. The models ensure QoS requirements of data flows and, at the same time, maximize the total revenue by adjusting parameters of the underlying schedulers. Deficit round robin (DRR) and deficit weighted round robin (DWRR) scheduling techniques have shown their ability in providing fair and weighted sharing of network resources for network devices. However, they are unable to use the total allocated network bandwidth even in burst traffic. In this paper, we propose a negative-deficit weighted round robin (N-DWRR) technique as a new packet scheduling discipline to improve the bandwidth utilization rate without increasing the total latency. A fully hardware packet scheduler has been implemented and verified as part of an intellectual property core. This is motivated by the fact that the design and analysis of hardware/software architectures for such techniques requires new models and methods, which do not fall under the domain of traditional embedded-systems design. [ABSTRACT FROM AUTHOR]

Cooperative work in learning environments has been shown to be a successful extension to traditional learning systems due to the great impact of cooperation on students' motivation and learning success. A recent evaluation study has confirmed our hypothesis that students who constructed their roles in a cryptographic protocol cooperatively as sequence of actions in a user interface were faster in finding a correct solution than students who worked on their own. Here, students of a cooperation group modeled a user interface collaboratively for simulation of a cryptographic protocol using interactive modeling tools on a shared touch screen. In this paper, we describe an extended approach to cooperative construction of cryptographic protocols. Using a formal language for modeling and reconfiguring user interfaces, students describe a protocol step-by-step, modeling subsequent situations and thereby actions of the protocol. The system automatically generates a colored Petri net, which is matched against an existing action logic specifying the protocol, thus allowing formal validation of the construction process. The formal approach to modeling of user interfaces covers a much broader field than a simple cryptographic protocol simulation. Still, this paper seeks at investigating the use of such a formal modeling approach in the context of cooperative learning of cryptographic protocols and to develop a basis for more complex learning scenarios. [ABSTRACT FROM AUTHOR]

In multi-synchronous collaboration users replicate shared data, modify it and redistribute modified versions of this data without the need of a central authority. However, in this model, no usage restriction mechanism was proposed to control what users can do with the data after it has been released to them. In this paper, we extend the multi-synchronous collaboration model with contracts that express usage restrictions and that are checked a posteriori by users when they receive the modified data. We propose a merging algorithm that deals not only with changes on data but also with contracts. A log auditing protocol is used to detect users who do not respect contracts and to adjust user trust levels. Our contract-based model was implemented and evaluated by using PeerSim simulator. [ABSTRACT FROM AUTHOR]

Testing is necessary to ensure the quality of web services that are loosely coupled, dynamic bound and integrated through standard protocols. Exhaustive testing of web services is usually impossible due to unavailable source code, diversified user requirements and large number of possible service combinations delivered by the open platform. This paper proposes a risk-based approach for selecting and prioritizing test cases for testing service-based systems. We specially address the problem in the context of semantic web services. Semantic web services introduce semantics to service integration and interoperation using ontology models and specifications. Semantic errors are considered more difficult to detect than syntactic errors. Due to the complexity of conceptual uniformity, it is hard to ensure the completeness, consistency and unified quality of ontology model. A failure of the semantic service-based software may result from many factors such as misused data, unsuccessful service binding, and unexpected usage scenarios. This work analyzes the two factors of risk estimation: failure probability and importance, from three aspects: ontology data, service and composite service. With this approach, test cases are associated to semantic features, and are scheduled based on the risks of their target features. Risk assessment is used to control the process of Web Services progressive group testing, including test case ranking, test case selection and service ruling out. This paper discusses the control architecture and adaptive measurement mechanism for adaptive group testing. As a statistical testing technique, the proposed approach aims to detect, as early as possible, the problems with highest impact on the users. [ABSTRACT FROM AUTHOR]

We propose a novel representation of 3D face shape which is a key step for feature extraction and face recognition. The input of the proposed methods is unstructured point cloud, which determines the wide applicability of the proposed representation. Our contributions mainly include two parts: Spherical Depth Map (SDM) and face alignment based on SDM. SDM, which can be adopted to many applications, is a special kind of range image utilizing the prior anatomical knowledge of human face. Useful characteristics of SDM facilitate face alignment with higher efficiency and accuracy. Experiments conducted on three popular 3D face databases verify the high efficacy and superiority of the proposed method. The accuracy of face alignment is up to 100% with our strategy. The face verification rates based on the standard protocols are all higher than the baseline performance of FRGC2.0. [ABSTRACT FROM AUTHOR]

Recently, growing privacy concerns have received more and more attention and it becomes a significant topic on how to preserve private-sensitive information from being violated in distributed cooperative computation. In this paper, we first propose a novel-general privacy-preserving online analytical processing model based on secure multiparty computation. Then, based on the new model, two schemes to privacy-preserving count aggregate query over both horizontally partitioned data and vertically partitioned data are proposed. Additionally, we also propose several efficient subprotocols that serve as the basic secure buildings. Furthermore, we analyze correctness, security, communication cost, and computation complexity of our proposed protocols, and show that the new schemes are secure, having good linear complexity and that the query results are exactly accurate. [ABSTRACT FROM AUTHOR]

We define the reversion protocol of a voluntarily implementable Bayesian mechanism in which risk-averse players have no incentive to cheat or to deviate from the mediator's recommendation and that can greatly improve their equilibrium expected pay-offs as compared to those generated through coordination applied to the results of an unsatisfactory mediation. [ABSTRACT FROM AUTHOR]

Developing and maintaining reliable object-oriented software requires a precise understanding of how individual classes must be used. Unfortunately, for many systems, especially those that are large, the available documentation is inadequate. Developers are left with incomplete information concerning the allowable set of call sequences that each class can accommodate. Techniques for reverse engineering this information and presenting it to developers in an intellectually scalable manner are critical. In this paper, we present four contributions to address this challenge. First, we describe a runtime trace collection system for large C++ applications. Second, we present a methodology for reverse engineering interface protocols from collected trace data. Third, we present a scalable, tunable algorithm for generating compact specifications of these protocols. Finally, we present a detailed case study involving the Mozilla Necko library. We consider popular applications in common use constructed using this library. The results are promising both in terms of the performance of the approach and the utility of the identified protocols. [ABSTRACT FROM AUTHOR]

As an inexpensive, flexible, and scalable Internet-access wireless network, we have studied the architecture, protocols, and design optimizations of the Wireless Internet-access Mesh NETwork (WIMNET) that adopts multiple access-points (APs) connected through wireless links. WIMNET can improve the dependability to failures of APs and/or their links by allocating APs redundantly in the network field. Because redundant APs may increase the operational cost and degrade the throughput due to increasing radio interferences, only the necessary APs for connectivity between the hosts and the Internet gateway should be activated in communications. In this paper, we first define the active AP selection problem of selecting the minimum number of active APs, and prove the NP-completeness of its decision version through reduction from the known minimum set cover problem. Then, we propose an active AP selection algorithm of deactivating APs one by one until no more AP can be deactivated. Due to the limited transmission capacity in WIMNET, we further present an algorithm extension for throughput maximization. We verify the effectiveness of our proposal through simulations in three instances, where the number of active APs is reduced by more than 40% and the throughput is improved by more than 10% from the original in any instance. [ABSTRACT FROM AUTHOR]

Opportunistic Networks are examples of wireless, ad hoc networks where there is an absence of a continuous end-to-end path. The proliferation of mobile device usage creates opportunities for nodes to forward packets in a dynamic way, utilizing nodes as they present themselves. In more conventional, static network infrastructures, it is typical to measure efficiency of message passing between nodes. We review approaches to the measurement of efficiency in networks, and propose a qualitative and quantitative metrics framework and simulation model that would be suitable for the evaluation of performance in opportunistic networks. [ABSTRACT FROM AUTHOR]

A supply chain comprises several different kinds of actors that interact either in an ad hoc fashion (e.g. an eventual deal) or in a previously well-planned way. In the latter, how the interactions develop is described in contracts that are agreed on before the interactions start. This agreement may involve several partners, thus a multi-party contract is better suited than a set of bi-lateral contracts. If one is willing to negotiate automatically such kind of contracts, an appropriate negotiation protocol should be at hand. However, the ones for bi-lateral contracts are not suitable for multi-party contracts, e.g. the way to achieve consensus when only two negotiators are haggling over some issues is quite different if there are several negotiators involved. In the first case, a simple bargain would suffice, but in the latter a ballot process is needed. This paper briefly presents our negotiation protocol for electronic multi-party contracts which seamlessly combines several negotiation styles. It also elaborates on the main negotiation patterns the protocol allows for: bargain (for peer-to-peer negotiation), auction (when there is competition among the negotiators) and ballot (when the negotiation aims at consensus) and presents other patterns that can be built on these basic ones. Finally, it describes an implementation of this protocol based on Web services, and built on the YAWL Workflow Management System. [ABSTRACT FROM AUTHOR]

Recently, Shieh et al. have pointed out that Juang's password authenticated key agreement scheme and Chien et al.'s remote authentication scheme are vulnerable to some attacks. Therefore, they presented a modified protocol to avoid those attacks. However, the authors of this article shall show that Shieh et al.'s scheme and Juang's scheme have two weaknesses, respectively. Therefore, we shall improve the weaknesses of their schemes. [ABSTRACT FROM AUTHOR]

This paper presents an application of the multi-agent system approach to mobile manipulators that cooperate to achieve displacement of heavy and large objects. Therefore, the task is distributed between agents, and each agent offers and negotiates its services that help in accomplishing the mission. The multi-agent system has been developed using the oRis platform. The main components of such a system include communication and negotiation protocols. Hence we present the behavior of robots, their interaction, and their behavior toward obstacles. Computer simulations are conducted in order to demonstrate the feasibility of the proposed approach. [ABSTRACT FROM AUTHOR]

This paper deals with the use of a minimal model for performing secure computations. The communication is based on a protocol which makes use of disjoint function decomposition and more precisely of minimal ESCT (Exclusive-or Sum of Complex Terms) expressions in order to perform a secure computation. The complexity of this protocol is directly proportional to the size of the ESCT expression in use, which is much smaller in comparison to other proposed minimal models (e.g., ESOP). Moreover, quantum algorithms are discussed that provide significant speedup to the process of producing the ESCT expressions, when compared to conventional ones. Hence, this paper provides a very useful application of the ESCT expressions in the field of cryptographic protocols. [ABSTRACT FROM AUTHOR]

New real-time applications frequently involve timing constraints related to accurate services from communication protocols. Concretely, real-time communication protocols utilize timers to implement these constraints between system event occurrences. In this context, the study of congestion control for Internet reliable multicast is at present an active research field related to real-time protocols. In this paper, the authors present an innovative real-time transport protocol named Scalable Reliable Multicast Stair Hybrid (SRMSH) as new hybrid multiple layer mechanism for multicast congestion control providing detection and recovery loss. This work is focused on formal specification of SRMSH approach using Communicating Real-Time State Machines as a formal method. Besides, SRMSH validation is presented within a formal proof framework in order to check the functional safety and liveness properties. As a result, authors outline a dynamical system framework in order to model behavior of their presented solution. [ABSTRACT FROM AUTHOR]

Services as abstractions of functionality have enabled the engineering of systems that support well-defined processes with relative ease. This success leads to aspirations for achieving greater complexity with the service-oriented paradigm. In particular, we address the case where the process definition is tailored differently in each instantiation based on negotiations among stakeholders of a socio-technical context. For such cases the process definition invariably crosscuts the architecture of a process-support system that composes available services. However, use of pre-defined process variations may bias the tailoring effort and thus, act against the original motivation of having a flexible definition. On the other hand, the characteristics of process complexity and tailorability introduce differences between stakeholder understanding of the process activities and their manifestation in tool support. We encounter these issues while developing a service-oriented process-support system for a security Certification and Accreditation (C&A) process. In this paper, we present our approach to effectively separate the C&A process definition from the architecture of its process-support system. We employ ontological modeling techniques to explicitly model the process definition and later expose it as a service to provide weaving rules for dynamically composing the process-support system architecture at runtime. The feasibility of our approach has been demonstrated in the design of a service-oriented architecture for a prototype workbench that supports the Department of Defense Certification and Accreditation Process (DITSCAP). [ABSTRACT FROM AUTHOR]

Genetic programming (GP) is known to provide good solutions for many problems like the evolution of network protocols and distributed algorithms. In most cases it is a hardwired module of a design framework assisting the engineer in optimizing specific aspects in system development. In this article, we show how the utility of GP can be increased remarkably by isolating it as a component and integrating it into the model-driven software development process. Our GP framework produces XMI-encoded UML models that can easily be loaded into widely available modeling tools, which in turn offer code generation as well as additional analysis and test capabilities. We use the evolution of a distributed election algorithm as an example to illustrate how GP can be combined with model-driven development (MDD). [ABSTRACT FROM AUTHOR]

In this paper, we study the synchronization properties of random geometric graphs. We show that the onset of synchronization takes place roughly at the same value of the order parameter as a random graph with the same size and average connectivity. However, the dependence of the order parameter on the coupling strength indicates that the fully synchronized state is more easily attained in random graphs. We next focus on the complete synchronized state and show that this state is less stable for random geometric graphs than for other kinds of complex networks. Finally, a rewiring mechanism is proposed as a way to improve the stability of the fully synchronized state as well as to lower the value of the coupling strength at which it is achieved. Our work has important implications for the synchronization of wireless networks, and should provide valuable insights for the development and deployment of more efficient and robust distributed synchronization protocols for these systems. [ABSTRACT FROM AUTHOR]

There are many discussions on agreement protocols of multiple peer processes (peers) where every peer just aims at agreeing on one value out of values shown by the peers. In meetings of human societies, agreement procedures are so flexible that persons can change their opinions and can use not only all-condition where every person agrees on one value but also various types of agreement conditions like majority-condition. In this paper, we discuss a flexible agreement protocol of multiple peers by taking into account human behaviors in social agreement procedures. Each peer first takes a value v1 and notifies the other peers of the value v1. A peer pi in turn receives values from other peers. Unless a set of the values from all the peers satisfy the agreement condition, the peer pi can take another value v2. In order to model the social human behavior, in our previous work we discussed E- and P-precedent relations $\rightarrow_i^E$ and $\rightarrow_i^P$ on values of a peer pi. The relations $v_1 \rightarrow_i^E v_2$ and $v_1 \rightarrow_i^P v_2$ show that a peer pi can take a value v2 after taking a value v1 and prefers v1 to v2, respectively. If a peer autonomously takes values based on its precedent relations, the peers might not make an agreement even if there exists a satisfiable set of previous values. We discuss what previous values the peer can take again. In this paper, we try to find a satisfiable set of previous values in a history of values which the peers have so far taken, in addition for each peer to taking a new value at each round. [ABSTRACT FROM AUTHOR]

A wireless mobile sensor network is a collection of wireless mobile hosts forming nodes that are communicating without the aid of any centralized administration or standard support services. Nodes are classified as sensor nodes and router. Some nodes act both as sensors and routers. While traditional MAC protocols must balance between throughput, delay, and fairness concerns, WSN MAC protocols place an emphasis on energy efficiency as well. Schedule-based MAC protocols have been proposed for WSN. A common theme through all these protocols is putting radios to a low-power "sleep mode" either periodically or whenever possible when a node is neither receiving nor transmitting. In this paper, we propose a novel cluster-based infrastructure creation protocol, namely: the Neighbor-Aware Clusterhead (NAC). We investigate the performance of the NAC protocol under different sleep scheduling protocols and compare it against another cluster-based protocol. In NAC protocol nodes are synchronized with their clusterheads and are allowed to go sleep mode in order to conserve their energy without degrading the performance of the network. The network is divided into clusters managed by a clusterhead. The simulation results show that NAC protocol has a good potential to be a good candidate protocol for SNET. [ABSTRACT FROM AUTHOR]

Achieving efficient and fairness bandwidth allocations among connections in high bandwidth delay product networks has been a daunting challenge. Addressing the deficiency of previous protocols, this paper presents a novel spectrum of Epoch Convergent Congestion Control protocols for deployment in high speed and long distance networks. Most of the end to end high speed protocols that has been presented can be seen as a member of ECCC. Through extensive analysis of ECCC, we focus on SQUARE, one of the protocols in Epoch Convergent Congestion Control. Without the need to revise the current end-to-end architecture, SQUARE is shown to be efficient when there is bandwidth available, to be fair when many flows compete with each other for the same bottleneck, to be friendly when deployed with the conventional TCP, to be robust when there are oscillations in the network. [ABSTRACT FROM AUTHOR]

Multi-hop ad hoc networks allow establishing local groups of communicating devices in a self-organizing way. However, when considering realistic mobility patterns, such networks most often get divided in a set of disjoint partitions. This presence of partitions is an obstacle to communication within these networks. Ad hoc networks are generally composed of devices capable of communicating in a geographical neighborhood for free (e.g. using Wi-Fi or Bluetooth). In most cases a communication infrastructure is available. It can be a set of access point as well as a GSM/UMTS network. The use of such an infrastructure is billed, but it permits to interconnect distant nodes, through what we call “bypass links”. The objective of our work is to optimize the placement of these long-range links. To this end we rely on small-world network properties, which consist in a high clustering coefficient and a low characteristic path length. In this article we investigate the use of three genetic algorithms (generational, steady-state, and cooperative coevolutionary) to optimize three instances of this topology control problem and present initial evidence of their capacity to solve it. [ABSTRACT FROM AUTHOR]

Service-Orientated Computing (SOC) has become a main trend in software engineering that promotes the construction of applications based on the notion of services. SOC has recently attracted the researchers' attention and has been adopted industry-wide. However, service composition that enables one to aggregate existing services into a new composite service is still a highly complex and critical task in service-oriented technology. To enhance availability of composite services, we propose a discovery-based service composition framework to better integrate component services in both static and dynamic manner, including (1) to devise a notion of service availability especially for composition; (2) to develop a dynamic service composition (DSC) pattern for addressing the issues of service availability; and (3) to extend Contract Net Protocol (ECNP) to coordinate service discovery, composition and invocation based on the composite pattern. The main benefit of the proposed approach is better availability through attaching multiple candidate services for future binding. [ABSTRACT FROM AUTHOR]

We describe a method of automating invariant verification of behavioral specifications, which are algebraic specifications of abstract machines. The proposed method is based on fixed-point computation, which is one of the standard techniques for automatic (invariant) verification. The proposed method has some notable features. Among them are as follow: (1) the method finds and uses as lemmas state predicates whose invariant proofs may (even mutually) depend on other state predicates whose invariant proofs may not be completed, and (2) the method finds a counterexample showing that an abstract machine does not satisfy an invariant property if any, which does not need to make the (reachable) state space of the abstract machine finite. Crème is a tool based on the proposed method. We also report on two case studies in which (1) Crème proves fully automatically that the NSLPK authentication protocol satisfies the secrecy property and (2) Crème finds a counterexample showing that the NSPK authentication protocol does not satisfy the secrecy property. [ABSTRACT FROM AUTHOR]

The need for empirical research and systematic performance evaluation of SEA, to advance theoretical understandings as well as practice, has been widely expressed. To promote such research any performance evaluation has to ensure that it is conceptually justified, methodologically sound, practically viable and tailored to the local context. This paper describes a SEA quality and effectiveness review protocol for application within the South African context. Based on international perspectives and debates it provides a description of the conceptual thinking underpinning the structure of the protocol in terms of its approach and framework as well as methodological justification on how the review areas and indicators were designed. Finally a critical evaluation of its application to selected case studies is presented. It concludes that the conceptual framework and methodology could be applied in any context although the contents in terms of review areas and indicators needs to be adapted to accommodate different understandings and perspectives on SEA. [ABSTRACT FROM AUTHOR]

In this paper we study a new class of generic, parametrized, locally load-sensing (LLS) network-routing protocols over simple graphs, Y. These protocols are Y-"local" in the sense that they transmit packets only between Y-adjacent vertices and LLS since they base their "routing decisions" dynamically on queue-sizes of their neighbors and their relative distance to the destination. In the system each vertex has specific data-queues indexed by its respective Y-neighbors. The state of a vertex then consists of the collection of queue-sizes. The data-transmission protocols are formally specified in the framework of sequential dynamical systems, which allows us to categorize and classify our experiments. We will investigate the following scenario: for fixed Y we assume a single source/destination pair to be given and a system-update then consists of the collection of local protocol updates according to some fixed permutation of the Y-vertices. We then iterate the system-updates and thereby obtain the time evolution of the queue-sizes of the vertices. We will present and discuss results on the evolution of the load, i.e. the total number of packets in the network, the throughput, i.e. the rate at which packets arrive at the destination, and study the dependence of the queue-size dynamics on various other system parameters. In particular, we will analyze update schedule dependency and the impact of queue-capacity on system stability. We will show that our protocols can adapt and dynamically utilize new routes in a fixed network. [ABSTRACT FROM AUTHOR]

In this paper, we design and implement a P2P cooperative proxy caching system based on a novel P2P cooperative proxy caching scheme. To effectively locate the cached web documents, a TTL-based routing protocol is proposed to manage the query and response messages in the P2P cooperative proxy cache system. Furthermore, we design a predict query-route algorithm to improve the TTL-based routing protocol by adding extra information in the query message packets. To select a suitable cache replacement algorithm for the P2P cooperative proxy cache system, three different cache replacement algorithms, LRU, LFU and SIZE, are evaluated using web trace based performance studies on the implemented P2P cooperative proxy cache system. The experimental results show that LRU is an overall better cache replacement algorithm for the P2P proxy cache system although SIZE based cache replacement approach produces slightly better cache hit ratio when cache size is very small. The performance studies also demonstrate that the proposed message routing protocols significantly improve the performance of the P2P cooperative proxy cache system, in terms of cache hit ratio, byte hit ratio, user request latency, and the number of query messages generated in the proxy cache system, compared to the flooding based message routing protocol. [ABSTRACT FROM AUTHOR]

Distributed coordination function (DCF) is a primary random access mechanism of IEEE 802.11, which is the basic protocol of wireless LAN based on the CSMA/CA protocol. It enables fast installation with minimal management and maintenance costs and is a very robust protocol for the best effort service in wireless medium. The current DCF, however, is known to be unsuitable for real-time applications such as voice message transmission. In this paper, we focus on the performance issues of IEEE 802.11 which accommodates the prioritized messages. Existing results use the initial window size and backoff window-increasing factor as tools to handle the priority of the messages. Instead, we introduce a novel scheme which chooses the backoff timer with arbitrary probabilities. By this, one can greatly reduce the backoff delay of the lower priority messages without degrading the performance of higher priority. Additionally, we provide a step-by-step procedure which determines the system parameters such as the initial window size, backoff window-increasing factor, and the backoff timer choosing probabilities, guaranteeing the quality of service (QoS). [ABSTRACT FROM AUTHOR]

This paper gives an application of exclusive-or sum-of-products (ESOP) expressions to designing cryptographic protocols. That is, this paper deals with secure computations in a minimal model, and gives a protocol which securely computes every function by means of the techniques of ESOP expressions. The communication complexity of our protocol is proportional to the size of an obtained multiple-valued-input ESOP expression. Since the historical research on minimizing ESOP expressions is now still active, our protocol will "automatically" turn to an efficient one as this research progresses. Thus, we hope that the existence of our cryptographic protocol would motivate further research on minimizing ESOP expressions. [ABSTRACT FROM AUTHOR]

Current desktop environments provide weak support for carrying out complex user-oriented tasks. Although individual applications are becoming increasingly sophisticated and feature-rich, users must map their high-level goals to the low-level operational vocabulary of applications, and deal with a myriad of routine tasks (such as keeping up with email, keeping calendars and websites up-to-date, etc.). An alternative vision is that of a personal cognitive assistant. Like a good secretary, such an assistant would help users accomplish their high-level goals, coordinating the use of multiple applications, automatically handling routine tasks, and, most importantly, adapting to the individual needs of a user over time. In this paper we describe the architecture and its implementation for a personal cognitive assistant called RADAR. Key features include. (a) extensibility through the use of a plug-in agent architecture. (b) transparent integration with legacy applications and data of today's desktop environments, and. (c) extensive use of learning so that the environment adapts to the individual user over time. [ABSTRACT FROM AUTHOR]

In this paper we present Clustering Protocol for Sensor networks (CPS). Clustering techniques are used by different protocols and applications to increase scalability and reduce delays in sensor networks. Examples include routing protocols, and applications requiring efficient data aggregation. Our approach is based on the Covering Problem that aims at covering an area with minimum number of circular disks. CPS is a lightweight protocol that does not require any neighborhood information and imposes low communication overhead. We present simulation results to show the efficiency of CPS in both ideal cases and randomly distributed networks. Moreover, CPS is scalable with respect to density and network size. [ABSTRACT FROM AUTHOR]

In the role-based access control model, a role is a set of access rights. A subject doing jobs is granted roles showing the jobs in an enterprise. A transaction issued by a subject is associated with a subset of roles granted to the subject, which is named purpose. A method with a more significant purpose is performed before another method with a less significant purpose. We discuss which purpose is more significant than another purpose. We discuss two types of Role-Ordering (RO) schedulers SRO and PRO where multiple conflicting transactions are serializable in the significant order of subjects and purposes, respectively. We evaluate the RO schedulers compared with the traditional two-phase locking protocol in terms of throughput. [ABSTRACT FROM AUTHOR]

Reputation mechanisms for detecting and punishing free-riders in ad hoc networks depend on the local detection of selfish behavior. Although naive selfish strategies based on dropping data packets are readily detected, more sophisticated strategies that manipulate ad hoc routing protocols present a greater challenge. In this work we develop a method to distinguish selfish peers from cooperative ones based solely on local observations of AODV routing protocol behavior. Our approach uses the finite state machine model of locally observed AODV actions to build up a statistical description of the behavior of each neighbor. We apply a series of well-known statistical tests to features derived from this description to partition the set neighboring nodes into a cooperative and selfish class. Simulation results for a non-mobile ad hoc network show that our approach can detect two different types of routing manipulation while maintaining a low rate of false positives. [ABSTRACT FROM AUTHOR]

Nowadays, we can count several proposals about the micro-mobility problem in IP networks. In this paper, we try to summarize current proposals by means of a general classification scheme. Our taxonomy permits to identify pros and cons of current IP micromobility protocols. This classification should help understanding that e2e solutions do not cope with simultaneous movements of mobile nodes, and thus a mixed scheme would be better. Here, we design a new scheme, namely the smartAR scheme, which reduces network complexity and endures both single and simultaneous movements scenario. Moreover, we provide the classification of the IP micro-mobility protocols with a simple analysis of the hand-off latencies. [ABSTRACT FROM AUTHOR]

We present Delay-Energy Aware Routing (DEAP) a novel protocol for heterogeneous wireless ad hoc networks. DEAP is a crosslayer scheme that: first, manages adaptively the energy control by controlling the wakeup cycle of sensors based on the experienced packet delay; and second, rout packet in each hoc by distributing the load a group of neighboring nodes. The primary result of DEAP is that it enables a flexible and wide range of tradeoffs between the packet delay and the energy consumption. Therefore, DEAP supports delay sensitive applications of heterogeneous networks that include sensors and actors. DEAP is scalable to the change in network size, node type, node density and topology. DEAP accommodates seamlessly such network changes, including the presence of actors in heterogeneous sensor networks. Indeed, while DEAP does not count on actors, it takes advantage of them, and uses their resources when possible, thus reducing the energy consumption of sensor nodes. Through analysis and simulation evaluations, we show that DEAP improves the packet delay and network lifetime compared to other protocols. [ABSTRACT FROM AUTHOR]

In this paper we propose a new approach of application-level multicast protocol providing a group communication service. This protocol, called End-System Multicast (ESM), and can be used when native multicast routing is not available. ESM is a centralized protocol where everything is being controlled by a single host called Rendez-vous point (RPL1), connected indirectly to the group members via some hosts called secondary Rendez-vous Point (RPL2). Each RPL2 has some group members that constitute a cluster, and each cluster is controlled by its RPL2. Since the group control is divided among some RPL2 and a main controller (RPL1) manages the relation among RPL2s and between itself and RPL2s, we found that the scalability is improved and it also avoids the bottleneck problem near the RPL1, or there is a load balance. [ABSTRACT FROM AUTHOR]

ISO and IEC have jointly developed two Formal Description Techniques (FDTs) for specifying distributed real time systems such as computer/telecommunications protocols. These are Lotos and Estelle. In this paper, a formal method for automated transformation of a Lotos specification to an Estelle specification is presented. The method is applicable to various Lotos specification styles and to various communications protocols of ISO OSI layers. Our method has applications in conformance testing of such systems and building common semantic model for the various FDTs. In this paper, we develop an algorithm for constructing a 'Data Oriented'-Restricted Behavior Tree T that represent both the control flow aspects and the data flow aspects of the system. Then, we develop an algorithm for constructing the Estelle specifications from T. A minimization rule is also developed to optimize the size of the Estelle specification by reducing both the number of states and the number of transitions. [ABSTRACT FROM AUTHOR]

This paper describes Inter-frame Ling Signaling (ILS) protocol technology and its implementation in a 10-Gigabit Ethernet (10GbE) physical layer (PHY) LSI and optical transceiver module. The ILS can realize SDH/SONET-compatible operations, administration, maintenance, and provisioning (OAM&P) functions for PHY of 10GbE networks by inserting OAM&P information in the inter-frame gap periods. The coding features include 10GbE PHY upper compatibility, error detection capability, and disparity neutral characteristics. The 10GbE PHY LSI with the ILS function was fabricated using 0.18-um SOI CMOS technology to achieve high-speed and low-power performance. The main features of the high-speed circuit design are an inductive-load buffer, high-speed clock and data recovery (CDR), and pre-emphasis/equalizer circuits. The LSI function meets IEEE 802.3ae specifications with the very low-power consumption of about 1.2W. An XENPAK transceiver with ILS function using the LSI was also fabricated to make it easy to implement the ILS function in optical transport network systems such as WDM, OADM, OXC systems and L2/L3 switches. The key features of the module include a 1.3-um DFB laser module with highly reliable transmission performance and a small EML driver integrated module. ILS protocol operation is verified by experiment with XENPAK modules emulating the optical transport system. [ABSTRACT FROM AUTHOR]

We present Geometric Broadcast for Heterogeneous Sensor Networks (GBS), a novel broadcasting protocol for heterogeneous wireless sensor and actor networks. While broadcasting is a very energy expensive protocol, it is also widely used as a building block for a variety of other network layer protocols. Therefore, reducing the energy consumption by optimizing broadcasting is a major improvement in heterogenous sensor networking. GBS is a distributed algorithm where nodes make local decisions on whether to transmit based on a geometric approach. GBS does not need any neighborhood information and imposes very low communication overhead. GBS is scalable to the change in network size, node type, node density and topology. Furthermore it accommodates seamlessly such network changes, including the presence of actors in heterogeneous sensor networks. Indeed, GBS takes advantage of actor nodes, and uses their resources when possible, thus reducing the energy consumption by sensor nodes. Through simulation evaluations, we show that GBS is very scalable and its performance is improved by the presence of actors. At the best of our knowledge, GBS is the first broadcast protocol designed specifically for heterogeneous sensor and actor networks. [ABSTRACT FROM AUTHOR]