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Smart device networks form the backbone of many Internet of Things (IoT) applications. The performance of these systems depended on many factors. This includes their ability to connect to each other and network latency. In this paper, two algorithms are discussed that build a Peer-to-peer (P2P) overlay network. The focus is on real-time end-to-end remote instrumentation for IoT applications. P2P overlay networks are used for various purposes from content distribution through to media sharing. In contrast to traditional P2P systems, IoT systems can be highly sensitive to network latency and require low bandwidth. The main contributions of this paper are two algorithms to create overlay networks that assign peer nodes to super-peer nodes. The network contains a large number of smart devices and the key aim is to minimize system wide network latency. Other constraints regarding the nodes ability include the ability to become a super-peer node such as connectivity and limited processing capacities of the smart devices are also considered in context of a P2P remote instrumentation system. Both algorithms create a 3-hop network where the latency is lowered as much as possible with the given set of nodes. The algorithms have been validated through simulation. [ABSTRACT FROM AUTHOR]

The ARBITRARY PATTERN FORMATION (APF) is widely studied in distributed computing for swarm robots. This paper deals with the APF problem in an infinite grid under an asynchronous scheduler. In [Bose K, Adhikary R, Kundu MK, et al. Arbitrary pattern formation on infinite grid by asynchronous oblivious robots. Theor Comput Sci. 2020;815:213–227], the authors proposed an algorithm for APF problem in O B L O T model under an asynchronous scheduler, but the proposed algorithm was neither time optimal nor move optimal. This work provides two algorithms that solve APF problem in an asynchronous scheduler. The first algorithm is move optimal considering O B L O T model and the second algorithm is move and time optimal considering the L U M I model, where each robot has one light having three distinct colours. [ABSTRACT FROM AUTHOR]

We consider the decentralised consensus optimization problem in this paper. A fast decentralised gradient-based algorithm is proposed for a general class of problems with convex and differentiable objective functions. The developed method guarantees that all the nodes in the network would reach consensus on the global variable eventually. Based on the proposed decentralised algorithm, a broadcast-based protocol is designed, which is capable of providing solution for real-time in situ seismic imaging. Extensive numerical experiments on both synthetic and real sensor network seismic data sets validate the superior efficiency of the proposed algorithm over the other benchmarks. [ABSTRACT FROM AUTHOR]

To improve the overall system performance for distributed systems using mesh as their underlying structure, a hierarchical approach was proposed in [7]. The hierarchical configuration divides the mesh into clusters, thus allowing for processing to occur in small local groups at the lower levels. After local operations, the results are passed to higher logical levels. This method has been shown to be able to significantly reduce the total communication cost for the entire system. This paper is concerned with the hierarchical system's ability to handle node failure. When using a hierarchical configuration, certain nodes in the mesh become more important to the overall system than others. It is important that the hierarchical system have a reorganising mechanism in case of node failure, in such a way that the performance gain from hierarchical configuration is salvaged as much as possible. The work presented in this paper focuses on minimising the loss of performance in the system hierarchy due to the presence of failing nodes. We will propose fault-tolerance schemes for that purpose. The performance results will be compared to that of an ideal, fault-free system. We will present strategies to reconstruct the hierarchy, accommodating to the situation that some nodes in the original hierarchy are not functioning anymore. To that end, new local heads may be selected and local nodes regrouped. We will also present experiment results that examine the effectiveness of the proposed schemes. Examples of both faulty and fault-free hierarchical mesh systems will be tested to quantify how good the proposed schemes are. [ABSTRACT FROM AUTHOR]

In this paper, classes of automata that perform distributed computations with unconventional interaction are described and studied. These automata are called selective machines and they are more powerful than Turing machines while their high computing and recognising power can be achieved exclusively by interaction when a system of recursive algorithms (automata) becomes super-recursive due to their interaction. Computations of selective machines are described by selective algorithms, which are super-recursive allowing computations of functions that are incomputable by Turing machines. Examples of selective algorithms are grammars with prohibition, correction grammars and grammars with exclusion. The study of selective machines and selective algorithms is based on the axiomatic theory of algorithms, in which the results are obtained in the general situation of axiomatically defined classes of automata and algorithms. Then these results are specified for many concrete classes of automata and algorithms, such as finite automata or Turing machines, by checking the necessary axioms. [ABSTRACT FROM AUTHOR]

Over the last decade, several interconnected disruptions have happened in the large scale distributed and parallel computing landscape. The volume of data currently produced by various activities of the society has never been so big and is generated at an increasing speed. Data that is received in real-time can become way too valuable at the time it arrives and supports valuable decision making. Systems for managing data streams is not a recently developed concept but its becoming more important due to the multiplication of data stream sources in the context of IoT. This paper refers to the unique processing challenges posed by the nature of streams, and the related mechanisms used to face them in the big data era. Several cloud systems emerged to enable distributed processing of streams of big data. Distributed stream management systems (DSMS) along with their strengths and limitations are presented and compared. Computations in these systems demand elaborate orchestration over a collection of machines. Consequently, a classification and literature review on these systems' scheduling techniques and their enhancements is also provided. [ABSTRACT FROM AUTHOR]

Over the past few years, capturing the characteristics of the Gnutella overlay network has been one of the major research activities in distributed computing. While most of the works are focusing on the node degree distribution, upstream/downstream traffics and file distribution, only a few have been done on modeling the session lifetime distribution. A good model of the session lifetime distribution is basically a key to understand the formation and evolution of the topological structure of Gnutella. In this paper, the main objective is to present a measurement result we did in 2003 on the session lifetime distribution and make comparison with the results obtained by other researchers during 2001-2005. In accordance with our measurement, it is found that the lifetime distribution fits to a power law distribution with exponential cut-off. Specifically, for all t ≥ 15 min, [image omitted] . By inspecting the slopes of the log-log curve (i.e. [image omitted] ) at 20 min (i.e. short lifetime) and 600 min (i.e. long lifetime), it is also found that the shape of our model matches to those curves obtained by other researchers based on the measurements in 2001, 2002 and 2004. Therefore, it is observed that the session lifetime distribution of Gnutella might be an invariant characteristic independent of the technological advancement or protocol change during the period 2002-2005. [ABSTRACT FROM AUTHOR]

The concept of unreliable failure detector was introduced by Chandra and Toueg as a mechanism that provides information about process failures. This mechanism has been used to solve several agreement problems, such as the consensus problem. In this paper, algorithms that implement failure detectors in partially synchronous systems are presented. First two simple algorithms of the weakest class to solve the consensus problem, namely the Eventually Strong class (⋄S), are presented. While the first algorithm is wait-free, the second algorithm isf-resilient, wherefis a known upper bound on the number of faulty processes. Both algorithms guarantee that, eventually, all the correct processes agree permanently on a common correct process, i.e. they also implement a failure detector of the class Omega (Ω). They are also shown to be optimal in terms of the number of communication links used forever. Additionally, a wait-free algorithm that implements a failure detector of the Eventually Perfect class (⋄P) is presented. This algorithm is shown to be optimal in terms of the number of bidirectional links used forever. [ABSTRACT FROM AUTHOR]

Mobile agents have been widely used in distributed computing to take care of the task execution for the user. It is also suitable for mobile and pervasive computing. However, a pervasive computing environment is characterised by high diversity and dynamism, which gives rise to the requirement that a mobile agent executed in such environments has the self-configuring capability. In this paper, we study the problem, when an object providing a service enters the environment, how a mobile agent without prior knowledge about the object can interact with the service. We describe a method for the mobile agent to obtain the corresponding interaction codes and instantiate them for the interaction at runtime with minimal human involvement. We call this component-level self-configuration. Currently, no existing system renders a mobile agent with such capability. We propose a framework, which consists of a unified model for all the participating objects and mechanisms for a mobile agent to dynamically obtain interaction code and self-configuring it for execution. A prototype platform has been implemented and a preliminary performance study has also been carried out. Our experimental results show that the overhead caused by the component-level self-configuration is acceptable. [ABSTRACT FROM AUTHOR]

Checkpointing and rollback recovery are widely used techniques to handle failures in distributed computing systems. If there is no coordination among processes during checkpointing, processes may take useless checkpoints. Useless checkpoints are checkpoints that cannot be part of any consistent global checkpoint. In this paper, we propose a Communication-Induced checkpointing algorithm that prevents useless checkpoints by directing processes to take forced checkpoints more efficiently whenever a communication pattern that may lead to a Z-Cycle (ZC) is observed. Existence of ZC among checkpoints is known to be necessary and sufficient for making a checkpoint useless. The basic idea behind our algorithm can be extended to existing model-based checkpointing algorithms to reduce the number of forced checkpoints. We also compare the performance of our algorithm with an existing well-known algorithm. [ABSTRACT FROM AUTHOR]

Generalised matching network (GMN) is a newly introduced kind of interconnection network, which generalises hypercube-like network. This paper addresses the fault Hamiltonicity and fault Hamiltonian-connectivity of GMNs. Let G be a GMN with at least four building graphs, each of which is f-fault Hamiltonian-connected and [image omitted] -fault Hamiltonian. We prove that if G satisfies two more specified assumptions, then G is [image omitted] -fault Hamiltonian-connected and [image omitted] -fault Hamiltonian. [ABSTRACT FROM AUTHOR]

The existing searching schemes in peer-to-peer (P2P) networks are either forwarding-based or non-forwarding based. In forwarding-based schemes, queries are forwarded from the querying source to the query destination nodes. These schemes offer low state maintenance. However, querying sources do not entirely have control over query processing. In non-forwarding based methods, queries are not forwarded and the querying source directly probes its neighbors for the desired files. Non-forwarding searching provides querying sources flexible control over the searching process at the cost of high state maintenance. In this paper, we seek to combine the powers of both forwarding and non-forwarding searching schemes. We propose an approach where the querying source directly probes its own extended neighbors and forwards the query to a subset of its extended neighbors and guides these neighbors to probe their own extended neighbors on its behalf. Our approach can adapt query processing to the popularity of the sought files without having to maintain a large set of neighbors because its neighbors' neighbors are also in the searching scope due to the 1-hop forwarding inherent in our approach. It achieves a higher query efficiency than the forwarding scheme and a better success rate than the non-forwarding approach. To the best of our knowledge, the work in this paper is the first one to combine forwarding and non-forwarding P2P searching schemes. Experimental results demonstrate the effectiveness of our approach. [ABSTRACT FROM AUTHOR]

In response to the high demand of big data analytics, several programming models on large and distributed cluster systems have been proposed and implemented, such as MapReduce, Dryad and Pregel. However, compared with high performance computing areas, the basis and principles of computation and communication behaviour of big data analytics is not well studied. In this paper, we review the current big data computational model DOT and DOT Advanced, and propose a more general and practical model p-DOT (p-phases DOT). p-DOT is not a simple extension, but with profound significance: for general aspects, any big data analytics job execution expressed in DOT model or bulk synchronous parallel model can be represented by it; for practical aspects, it considers I/O behaviour to evaluate performance overhead. Moreover, we provide a cost function of p-DOT implying that the optimal number of machines is near-linear to the square root of input size for a fixed algorithm and workload, and certify that the processing paradigm of p-DOT is scalable and fault-tolerant. Finally, we demonstrate the effectiveness of the model through several experiments. [ABSTRACT FROM PUBLISHER]

In recent processors multicore and multithreaded architectures are widely used. This increases the number of contexts running in parallel. Contexts are competing for shared resources of the processor. One of these critical resources is system main memory. While execution, each context sends requests to the main memory to serve the cache misses. This introduces the need of memory access schedulers. In this paper, we propose two main ideas to be integrated with different existing algorithms. These two ideas arerelated requestsand starvation time threshold for memory requests. We integrated these ideas to three existing algorithms to come up with the following new algorithms: the fair least-request most related (FLRMR) algorithm, the fair issue-queue based most related (FIQMR) algorithm and the fair ready-to-inflight ratio most related (FRIRMR) based on the least request (LREQ) algorithm, the issue queue-based (IQ-based) algorithm and the ready-to-inflight ratio (RIR) algorithm, respectively. The results show that FLRMR, FIQMR and FRIRMR algorithms improve fairness over LREQ, IQ-based and RIR algorithms by,andon average, respectively. Moreover, compared to recently proposed techniques, on average, FLRMR achievesspeedup relative to the LREQ algorithm, FIQMR achievesspeedup relative to the IQ-based algorithm and FRIRMR achievesover the RIR algorithm. [ABSTRACT FROM PUBLISHER]

The development of distributed systems is an intricate task due to inherent characteristics of such systems. In this paper these characteristics are categorised into software engineering, concurrency, distribution and non-functional criteria. Popular classes of distributed systems are classified with respect to these challenges, and it is deduced that modern technological trends lead to the inception of new application classes with increased demands regarding challenges from more than one area. One recent example is the class of ubiquitous computing, which assumes dynamic scenarios in which devices come and go at any time. Furthermore, it is analysed to which extent today's prevailing software development paradigms – object, component, service and agent orientation – are conceptually capable of supporting the challenges. This comparison reveals that each of the paradigms has its own strengths and weaknesses and none addresses all of the challenges. The new active component approach is proposed aiming at a conceptual integration of the existing paradigms in order to tackle all challenges in an intuitive and unified way. The structure, behaviour and composition of active components are explained, and an infrastructure for active components is introduced. To underline the usefulness of the approach real-world applications is presented and an evaluation according to the challenges is given. [ABSTRACT FROM PUBLISHER]

The past few years have seen intensive research efforts carried out in some apparently unrelated areas of dynamic systems – delay-tolerant networks, opportunistic-mobility networks and social networks – obtaining closely related insights. Indeed, the concepts discovered in these investigations can be viewed as parts of the same conceptual universe, and the formal models proposed so far to express some specific concepts are the components of a larger formal description of this universe. The main contribution of this paper is to integrate the vast collection of concepts, formalisms and results found in the literature into a unified framework, which we call time-varying graphs (TVGs). Using this framework, it is possible to express directly in the same formalism not only the concepts common to all those different areas, but also those specific to each. Based on this definitional work, employing both existing results and original observations, we present a hierarchical classification of TVGs; each class corresponds to a significant property examined in the distributed computing literature. We then examine how TVGs can be used to study the evolution of network properties, and propose different techniques, depending on whether the indicators for these properties are atemporal (as in the majority of existing studies) or temporal. Finally, we briefly discuss the introduction of randomness in TVGs. [ABSTRACT FROM AUTHOR]

Wireless sensor networks and artificial immune systems are both self-managed distributed systems. This paper models a system mathematically to nodes route scheduling problem of global energy consumption and delay, and proposes a node scheduling scheme for minimum delay and energy efficient for wireless sensor network using the immune clone algorithm. The proposed scheme regards one data transmission at a certain moment as an antigen, potential routes as antibody and the delay and energy consumed by the node sequence as the fitness. The simulation results show that the proposed algorithm can not only avoid the collision among sensor nodes when forwarding data packets but also solve the global optimisation problem of power consumption and delay with fast convergence speed. [ABSTRACT FROM AUTHOR]

The research community has recently witnessed the emergence of multi-processor system on chip (MPSoC) platforms consisting of a large set of embedded processors. Particularly, Interconnect networks methodology based on network-on-chip (NoC) in MPSoC design is imminent to achieve high performance potential. More importantly, many well established schemes of networking and distributed systems inspire NoC design methodologies. Employing end-to-end congestion control is becoming more imminent in the design process of NoCs. This paper presents a centralised congestion control scheme in the presence of both elastic and streaming flow traffic mixture. We model the desired best effort source rates as the solution to an optimisation problem with weighted logarithmic objective which is known to admit proportional fairness criterion. The problem is constrained with link capacities while preserving guaranteed service traffics services requirements at the desired level. We propose an iterative algorithm as the solution to the optimisation problem which has the benefit of low complexity and fast convergence, and can be implemented by a controller unit with low computation and communication overhead. [ABSTRACT FROM AUTHOR]

The goal of the t/k-diagnosis is to isolate all faulty processors (nodes) in a multiprocessor system to within a set of nodes in which at most k nodes are correct, provided the number of faulty nodes does not exceed t. As compared to the classical precise diagnosis strategy, the t/k-diagnosis strategy can significantly improve the self-diagnosing capability of multiprocessor system. The generalised cube network (GCN), or equivalently the BC graphs, is a regular topology, which provides a unified view of the hypercube and some of its variants. This paper addressed the t/k-diagnosis of GCNs. By exploring the relationship between the size of a largest connected component of the 0-test subgraph of a faulty GCN and the distribution of the faulty nodes over the network, an [image omitted] time (4n - 9)/3 diagnosis algorithm on an n-dimensional GCN is presented, where N = 2n is the total number of the nodes of the network being diagnosed. To our knowledge, this is the first time to give a t/k-diagnosis algorithm for GCNs and [image omitted] . [ABSTRACT FROM AUTHOR]

In this paper, we present an efficient causal algorithm that can be used in multicast communication environments, in particular the overlapping multi-channel case, where a participant can belong to and communicate through more than one multicast channel. The causal algorithm is built on the paradigm of group communication. The groups are established according to the participant channel subscription. In order to reduce the amount of control information (CI), we propose an extension of the immediate dependency relation (IDR), which was introduced by Peterson in the context of one group. This IDR extension allows us to define necessary and sufficient CI to ensure causal delivery in a multi-group environment. We show that through the use of the IDR extension, we reduce the amount of CI sent per message without imposing restrictions on interaction or execution (e.g. network topology, rediffusion servers, execution models, etc.). These characteristics allow our algorithm to be suitable for use in large distributed decentralised systems. We show the efficiency of our causal algorithm in terms of the overhead timestamped per message. [ABSTRACT FROM AUTHOR]

Honeycomb meshes are a promising class of topological structures for connecting processors within parallel computing. This paper addresses three routing algorithms for these networks. First, a unicast algorithm known as XYZ-ROUTE is presented by employing the classical virtual channel technique. Second, the pre-algorithm is improved to make it work properly in the presence of a convex fault. Finally, a multicast algorithm is described by using multicast tree and sub-network techniques. [ABSTRACT FROM AUTHOR]

In this paper, we present a new, easy to implement algorithm for detecting the termination of a parallel asynchronous computation on distributed-memory MIMD computers. We demonstrate that it operates concurrently with the main computation, adding minimal overhead, and we prove that it correctly detects termination when it occurs. Experimental results confirm that the termination detection routine imposes an overhead smaller than the experimental uncertainty. [ABSTRACT FROM AUTHOR]

The article discusses papers published within the journal including "Matrix operation using arrays with reconfigurable optical buses," by S. Pavel and S.G. Akl, "Caching in with multigrid algorithms: problems in two dimensions," by C.C. Douglas and "On the double-vertex-cycle-connectivity of crossed cubes" by X. Yang and G.M. Megson.

In grid computing, many applications are invoked by the means of job submission. Grid job submission comprises the following scenarios: file stage-in, execution and file stage-out. Most of the grid midware provides the job submission infrastructure to help to submit jobs, and GridFTP (file downloading) is used in the file stage operations. These scenarios exit mostly in batch mode. It causes computational resources waiting for the data transfer and limits the performance of the grid application, especially when the application is data/communication intensive. Using the file sharing of distributed file system instead of GridFTP in the job submission, the scenarios of grid job submission can be processed in parallel, whereas the waiting of computational resource can be eliminated. By this way, the execution performance of the grid job is promoted. After the comparison of typical distributed file systems, network attached storage that meets the requirements of grid is picked out, and the file sharing mode for the data exchange in grid job is proposed. In the tests of a series of data–communication-intensive jobs, the performance promotion is verified. Comparing with GridFTP, the average promotion with Common Internet File System is 16.8% to single-task jobs and 19.5% to multiple-task jobs. [ABSTRACT FROM AUTHOR]

We propose a new mechanism for generating networks with a wide variety of degree distributions. The idea is a modification of the well-studied preferential attachment scheme in which the degree of each node is used to determine its evolving connectivity. Modifications to this base protocol to include features other than connectivity have been considered in building the network. However, some of the existing models are merely formulaic and do not offer an explanation that can be interpreted naturally or intuitively, while the others require certain information that is not available in many real-world circumstances. We propose instead a protocol based only on a single statistical feature which results from the reasonable assumption that the effect of various attributes, which determine the ability of each node to attract other nodes, is multiplicative. This composite attribute or fitness is lognormally distributed and is used in forming the complex network. We show that, by varying the parameters of the lognormal distribution, we can recover both exponential and power-law degree distributions. The exponents for the power-law case are in the correct range seen in real-world networks. Further, as power-law networks with exponents in the same range are a crucial ingredient of efficient search algorithms in P2P networks, we believe our network construct may serve as a basis for new protocols that will enable P2P networks to efficiently establish a topology conducive to optimised search procedures. [ABSTRACT FROM AUTHOR]

Security is an important concern in computer systems, which is especially remarkable when the system has to handle large amounts of data and some different users accessing this data with different accessing permissions. This work proposes an innovative approach for providing a security infrastructure support to Big Data Analytic in Cloud-based systems named Fast-sec. Fast-Sec handles systems with large volumes of data from heterogeneous sources, in which users may access the system by different platforms, consuming or providing data. The security infrastructure proposed in Fast-Sec provides an authentication mechanism for users, and data access control adapted to high demands from cloud-based Big Data environment. The reported results show the adequacy of the proposed safety infrastructure to the cloud-based systems processing Big Data. [ABSTRACT FROM AUTHOR]

As a paradigm of computation, reservoir computing has gained an enormous momentum. In principle, any sufficiently complex dynamical system equipped with a readout layer can be used for any computation. This can be achieved by only adjusting the readout layer. Owning to this inherent flexibility of implementation, new applications of reservoir computing are being reported at a constant rate. However, relatively few studies focus on sensing, and in the ones that do, the reservoir is often exploited in a somewhat passive manner. The reservoir is used to post-process the signal from sensing elements that are placed separately, and the reservoir could be replaced by other information processing system without loss of functionality of the sensor (‘reservoir computingandsensing’). An entirely different novel class of sensing approaches is being suggested, to be referred to as ‘reservoir computing for sensing’, where the reservoir plays a central role. In the State Weaving Environment Echo Tracker (SWEET) sensing approach, the reservoir functions as the sensing element if the dynamical states of the reservoir and the environment one wishes to analyze are strongly interwoven. Some distinct characteristics of reservoir computing (in particular the separability and the echo state properties) are carefully exploited to achieve sensing functionality. The SWEET approach is formulated both as a generic device setup, and as an abstract mathematical algorithm. This algorithmic template could be used to develop a theory (or a class of theories) of ‘reservoir computing for sensing’, which could provide guidelines for engineering novel sensing applications. It could also provide ideas for a creative recycling of the existing sensing solutions. For example, the Horizon 2020 project RECORD-IT (Reservoir Computing with Real-time Data for future IT) exploits the SWEET sensing algorithm for ion detection. Accordingly, the terms SWEET sensing algorithm and the RECORD-IT sensing algorithm can be used interchangeably. [ABSTRACT FROM PUBLISHER]

A fundamental problem of distributed systems, leader election, is presented in the context of mobile ad hoc networks (MANETs). In many distributed systems, the presence of a leader is necessary in order to monitor underlying computations, guarantee quality functioning, take checkpoints, generate the lost token, detect quiescence conditions, etc. Hence, several leader election algorithms have been proposed in the literature. Although, most of the algorithms focus on reducing the control message (messages that have the highest priority to deliver) count, there have been almost no attention on ensuring high availability of a leader despite various types of failures, especially, in the scenarios like rescue and warfare, where the absence of the leader, even for a short duration, may lead to havoc. We focus on this issue, particularly, for large MANETs, where a large number of applications fails to perform in the absence of a leader. We present a leader election algorithm for large MANETs. The algorithm is inspired by the concept of prevailing parliamentary democracy and elects three best-nodes – in terms of performance parameters like battery life, computing power, memory, hop distance, and mobility – as the president, leader, and vice leader. The president node works as the leader of the network, in case, the leader and the vice leader both become unavailable simultaneously. On the other hand, the leader node serves all the requests. Further, we create a house of elite nodes, which ensures the presence of an executive, i.e. a leader during re-election to restrict the message overhead as well as the election latency while executing coordination related activities. Failure of the special nodes. [ABSTRACT FROM PUBLISHER]

Reliable multicast provides an elegant mechanism for structuring communication among closely cooperating entities. In a distributed mobile computing environment, disconnections and physical mobility of the mobile hosts (MHs) may result in the loss of messages. This makes the problem of ensuring reliable multicast difficult for MHs. Apart from ensuring reliable message delivery, guaranteeing exactly once message delivery greatly helps in conserving the battery power. Moreover, for transaction-based applications, total ordering of messages are semantically essential. In this report, an exactly once multicast protocol (called EOMP) with totally ordered message delivery is proposed. An unreliable wireless MAC level multicast is used for delivering the messages to the MHs and a novel mechanism for multicasting messages in the cellular network is proposed. An EOMP tolerates mobile support station (MSS) failure by making the MSS stateless. Dynamic host group membership is also supported by an EOMP. The performance of EOMP has been evaluated and compared with an existing an EOMP by simulation. The results of the simulation show that an EOMP has lower delay, lesser handoff, reduced buffer space overhead, and are more scalable. To establish the effectiveness of a reliable multicast protocol with totally ordered message delivery for mobile systems, two different applications viz., a real-time distributed collaborative text editor and a distributed image rendering application, were developed as case studies. The applications were easy to develop as mobility and disconnection were hidden from the application by an EOMP. The applications are also efficient as they use a powerful reliable multicast primitive for communication. [ABSTRACT FROM AUTHOR]

Monitoring and predicate detection is a fundamental challenge of evaluating whether or not a predicate has held on the state of a distributed system in an execution. We solve eventually perfect predicate detection in a failure-prone system assuming that only the average response time is finite. The solution is based on an eventually accurate failure detection sequencer ([image omitted] ) which we propose and implement in the finite average response time system. We prove that [image omitted] can solve eventually perfect detection of predicates involving process operational status. This research contributes to identifying realistic detection semantics in a weak partially synchronous model. Our approach has a layered model with which applications have the flexibility to choose appropriate predicate detection algorithms with the possibility to solve different predicate modalities. [ABSTRACT FROM AUTHOR]

We present an optimistic approach for consistent, interactive steering of distributed computations. In contrast to conservative approaches, the optimistic steering approach assumes that next steerable points are consistent and invokes steering updates without concern for the state of any other process. This approach is expected to perform well since it eliminates the need for blocking processes. Furthermore, we introduce a novel transaction-based computation model. We view the local computation of a process as a sequence of local transactions and a distributed computation as a set of partially ordered global transactions. This abstraction not only gives users a simple and high-level view of distributed computation, but also simplifies reasoning about consistency problems by reducing the amount of information to be handled. Using the Higher KdV (HiKdV) equation simulation program, we evaluate the performance of the optimistic steering approach. Our experiments show that when the percentages of consistency on the first attempt are large enough, the optimistic approach will achieve better performance; otherwise, the conservative approach will be better. [ABSTRACT FROM AUTHOR]