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Summary: In distributed systems, tuple space is one of the coordination models that significantly maximizes system performance against failure due to its space and time decoupling features. With the growing popularity of distributed computing and increasing complexity in the network, host and link failure occurs frequently, resulting in poor system performance. This article proposes a fault‐tolerant model named Tuple Space Replication (TSR) for tuple space coordination in distributed environments. The model introduces a multi‐agent system that consists of multiple hosts. Each host in a multi‐agent system comprises an agent space with a tuple space for coordination. In this model, we introduce three novel fault‐tolerant algorithms for tuple space primitives to provide coordination among hosts with tolerance to multiple links and hosts failure. The first algorithm is given for out() operation to insert tuples in the tuple space. The second algorithm is presented for rdp() operation to read any tuple from the tuple space. The third algorithm is given for inp() operation to delete or withdraw tuples from the tuple space. These algorithms use less number of messages to ensure consistency in the system. The message complexity of the proposed algorithms is analyzed and found O(n) for out(), O(1) for rdp(), and O(n) for inp() operations which is comparable and better than existing works, where n is the number of hosts. The testbed experiment reveals that the proposed TSR model gives performance improvement up to 88%, 70.94%, and 63.80% for out(), rdp(), and inp() operations compared to existing models such as FT‐SHE, LBTS, DEPSPACE, and E‐DEPSPACE. [ABSTRACT FROM AUTHOR]

Smart grids play an important role for energy management by directly supporting the socio-ecological transition of neighbourhoods. This research provides the design of a coordination model to enable the management and exchange of electrical energy between producers and consumers at a micro-grid level. This model, which derives from the SAPERE coordination model, allows the intelligent digital twins to interact and generate services on the fly to meet different needs in real time. We have designed producer and consumer digital twins, which autonomously generate supply contracts in the form of a transaction, and supervisor digital twins, which regulate energy at the node level, managing threshold violations and proactively avoiding future threshold violations by using predictions. This coordination model allows energy exchanges in a single node and in a micro-grid structure that contains several neighbouring nodes. We have implemented and tested the platform with realistic data, based on the consumption statistics of a real household, and with real data, collected in the living-lab of "Les Vergers" located near Geneva. The results show that the combination of a coordination model and intelligent digital twins actually supports self-adaptive energy management in a smart grid. Such approaches are fundamental to develop efficient and reliable smart grids. [ABSTRACT FROM AUTHOR]

Smart grids play an important role for energy management by directly supporting the socio-ecological transition of neighbourhoods. This research provides the design of a coordination model to enable the management and exchange of electrical energy between producers and consumers at a micro-grid level. This model, which derives from the SAPERE coordination model, allows the intelligent digital twins to interact and generate services on the fly to meet different needs in real time. We have designed producer and consumer digital twins, which autonomously generate supply contracts in the form of a transaction, and supervisor digital twins, which regulate energy at the node level, managing threshold violations and proactively avoiding future threshold violations by using predictions. This coordination model allows energy exchanges in a single node and in a micro-grid structure that contains several neighbouring nodes. We have implemented and tested the platform with realistic data, based on the consumption statistics of a real household, and with real data, collected in the living-lab of “Les Vergers” located near Geneva. The results show that the combination of a coordination model and intelligent digital twins actually supports self-adaptive energy management in a smart grid. Such approaches are fundamental to develop efficient and reliable smart grids.

Abstract Conceptually, tuple spaces are shared memory objects that provide operations to store and retrieve ordered sets of data, called tuples. Tuples stored in a tuple space are accessed by the contents of their fields, working as an associative memory. Although there are some proposals for secure tuple spaces, accessing tuples through field contents makes these systems susceptible to attacks that could impair user and data privacy, since servers must access tuple data. In order to deal with these limitations and provide privacy in the tuple space model, this paper proposes some extensions to DepSpace, a tuple space system that implements dependability and security properties through a set of mechanisms that are not enough to ensure privacy. The resulting system provides privacy and, at the same time, allows tuple selection/matches similar to the traditional insecure model, i.e., it does not constraint the matching possibilities. The main problem to be addressed is that servers must select tuples based on their contents without knowing them. The proposed solution uses robust cryptographic schemes, as order-preserving encryption and homomorphic encryption, to provide this functionality without revealing the tuple contents. An analysis concerning security aspects of DepSpace is presented, as well as the benefits of the proposed solutions. A set of experiments, executed with an implementation of the proposed protocols, shows the feasibility of the proposed solutions and shed some light on both the behavior of the system and the costs to provide privacy in the tuple spaces model.

Abstract Tuple Spaces have long been recognized as a simple and elegant model for parallel and distributed computing. This is mainly because of spatial and temporal uncoupling of system components, which simplifies inter-process communication as well as component inclusion and replacement. However, Tuple Spaces have shown scalability limitations when employed in large scale and highly demanding contexts. In order to deal with this problem, "bioinspired" techniques based on swarm intelligence including SwarmLinda and Anti-Over-Clustering have been proposed. This work shows that although these approaches do improve the system scalability, they end up producing an important degradation on tuple search performance, due to poor tuple placement. By applying the concept of "virtual magnetic fields" to swarms, a novel solution called Magnetic SwarmLinda is proposed. Magnetic SwarmLinda arranges tuples in expandable clusters of clusters (called " magnetic clusters ") naturally providing load balancing among the supporting computing nodes. Simulation results show that the proposed strategy outperforms previous approaches in most scenarios. Highlights • A scalable bioinspired method for data retrieval in distributed spaces is proposed. • The behavior of data retrieving agents is affected by virtual magnetic fields. • Simulation results in six different scenarios bring about the method strengths. • Comparisons with previous approaches show how better performance was achieved. [ABSTRACT FROM AUTHOR]

Summary: Among the paradigms for parallel and distributed computing, the one popularized with Linda, and based on tuple spaces, is one of the least used, despite the fact of being intuitive, easy to understand, and easy to use. A tuple space is a repository, where processes can add, withdraw, or read tuples by means of atomic operations. Tuples may contain different values, and processes can inspect their content via pattern matching. The lack of a reference implementation for this paradigm has prevented its wide spreading. In this paper, first we perform an extensive analysis of a number of actual implementations of the tuple space paradigm and summarize their main features. Then, we select four such implementations and compare their performances on four different case studies that aim at stressing different aspects of computing, such as communication, data manipulation, and CPU usage. After reasoning on strengths and weaknesses of the four implementations, we conclude with some recommendations for future work towards building an effective implementation of the tuple space paradigm. [ABSTRACT FROM AUTHOR]

Conceptually, tuple spaces are shared memory objects that provide operations to store and retrieve ordered sets of data, called tuples. Tuples stored in a tuple space are accessed by the contents of their fields, working as an associative memory. Although there are some proposals for secure tuple spaces, accessing tuples through field contents makes these systems susceptible to attacks that could impair user and data privacy, since servers must access tuple data. In order to deal with these limitations and provide privacy in the tuple space model, this paper proposes some extensions to DepSpace, a tuple space system that implements dependability and security properties through a set of mechanisms that are not enough to ensure privacy. The resulting system provides privacy and, at the same time, allows tuple selection/matches similar to the traditional insecure model, i.e., it does not constraint the matching possibilities. The main problem to be addressed is that servers must select tuples based on their contents without knowing them. The proposed solution uses robust cryptographic schemes, as order-preserving encryption and homomorphic encryption, to provide this functionality without revealing the tuple contents. An analysis concerning security aspects of DepSpace is presented, as well as the benefits of the proposed solutions. A set of experiments, executed with an implementation of the proposed protocols, shows the feasibility of the proposed solutions and shed some light on both the behavior of the system and the costs to provide privacy in the tuple spaces model. [ABSTRACT FROM AUTHOR]

Based on dimension decomposition idea,a high-performance two-dimensional packet classification algorithm by jointing tuple space and bitmap technology,called TB,was designed and implemented.Firstly,TB processes one-dimension matching for SIP and DIP respectively,then it forms tuple space access route by applying the cross-combination method to the matching results in the first step,finally,to reduce the number of required accessing tuple space,TB obtains the multi-dimensional matched rule by adapting bitmap filtering technique to filter tuple space.Compared to traditional tuple space algorithm,the structure of TB is clearer,more concise and easier to update and implement,TB also has better time and space performance.The experimental results show that TB algorithm saves 35.1% of the space requirement than RSFR algorithm and the number of average memory accesses lower than RSFR 26.6%.

A mobile cloud computing paradigm supports different resource-intensive mobile applications by leasing various mobile cloud services, thus helping these applications to overcome the inherent shortcomings of mobile ∕ portable devices of end users. However, mobile cloud services in existing architectures become tightly coupled with mobile applications during servicing, which is highly undesirable because of the dynamic nature of the mobile cloud computing paradigm. A new mobile cloud architecture, where the interactions between mobile applications and mobile cloud services are decoupled during service invocation and delivery phases, is proposed in this paper. The tuple space model is used in this architecture to decouple such interactions, thereby improving adaptability and robustness of mobile cloud computing. This paper also suggests an approach of modeling and formally verifying the correctness of the proposed architecture, which also validates its adaptability and robustness during interactions between mobile applications and mobile cloud services. The modeling and verification are carried out using the Mobile UNITY model. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Highlights: [•] We present a semantic distributed middleware designed for AmI and IoT environments. [•] Adapting it to different platforms is straightforward due to its design. [•] A case of study is presented to fully explain the benefits of using our middleware. [•] We assess three different implementations of our middleware. [Copyright &y& Elsevier]

One main issue associated with the efficient and effective use of heterogeneous resources in a grid system is the scheduling. Scheduling in a grid system involves a number of challenging issues mainly due to the dynamic nature of the grid. Schedulers on traditional grid infrastructures rely on an information service that provides information about resources capacities and availability. However, in an asynchronous distributed system like a grid providing up-to-date information about resources is difficult. Current scheduling algorithms make scheduling decisions without fully accurate information about resources which can lead to inefficient schedules. This paper proposes a new scheduling infrastructure for grids where resources select tasks they execute, instead of the traditional approach where schedulers finding resources for the tasks. The new proposed approach allows, at any time, to make scheduling decisions with up-to-date/accurate information. Moreover, our infrastructure provides mechanisms to provide a fault tolerant scheduling. The proposed infrastructure is mainly based on the tuple space coordination model. In our evaluation study, a number of experiments with various simulation setting demonstrated the practicability of proposed infrastructure. [ABSTRACT FROM AUTHOR]

The computational grid is rapidly evolving into a large-scale computing infrastructure that facilitates resource sharing and problem solving over the Internet. Information services play a crucial role in grid environments for discovery of resources. The dynamic nature and the large-scale of a grid pose many challenges to information services in terms of scalability and resilience. This paper presents RDSpace which can be used as a substrate for resource discovery in grid environments. RDSpace builds a shared tuple space on top of a structured peer-to-peer overlay to achieve high scalability in dealing with a large number of computing nodes and to support range queries in discovery of resources. Another novelty of RDSpace lies in its capability to handle churn situations where nodes may join or leave the space frequently. RDSpace is evaluated from the aspects of scalability and churn handling, and the evaluation results are also presented in this paper. [ABSTRACT FROM AUTHOR]

In this research work, a fault tolerant extension of the de facto message passing system parallel virtual machine, TS- parallel virtual machine, is introduced. This extension enables real time applications over parallel virtual machine. In PVM and similar message passing systems, if the message receiver is not available, due to network failure or machine crash, a failure is reported and data must be resent. If the transferred data is persistent, i.e. should not be lost, then it is important to provide the system with failure recovery mechanisms. The idea behind the proposed extension, TS- parallel virtual machine, is to integrate a fault tolerant distributed shared memory layer, in parallel virtual machine. Such layer has been inherited from the TRIPS system that supports fault tolerance over a DSM The challenge of this research work is the integration of a DSM layer in a message passing system. The proposed parallel virtual machine extension would have bad performance of compared to the pure message passing one. On the other hand, the real time application can be completed in spite of failures occurrence. [ABSTRACT FROM AUTHOR]

Abstract: Mobile ad hoc networks (MANETs) are gaining importance as a promising technology for flexible, proximity-based, mobile communication. However, the inherent dynamics of MANETs imposes strong limitations on the design of distributed applications. They need to be able to adapt to changing conditions quickly and organize themselves in terms of component placement and communication habits. In this paper, we present MESHMdl , a middleware that provides a high level of awareness and decoupling for application components to make them more flexible and adaptable. We focus on the Event Space as the central communication medium of MESHMdl . The Event Space offers a simple, unified communication interface for inter-agent communication as well as for communication with the middleware and resource access. Furthermore, it serves as a means for flexibly extending a MESHMdl  daemon. We investigate the performance of the Event Space on different mobile devices and show that it is superior to comparable systems. [Copyright &y& Elsevier]

Research on peer-to-peer (P2P) networks has attracted much attention recently. A key factor is their ability to handle dynamics in the system in a distributed fashion, including ad hoc and dynamic join and departure of the peers and dynamic changes in the underlying network environment. As more and more innovating P2P applications appear, the need to support intuitive communication and synchronization among the peers in the P2P system becomes imperative. In this paper, we discuss how to build a tuple space on top of P2P systems and use on-line games as a target application. A simple API is supported for accessing the data stored in the tuple space and communicating between the peers. Through experiments and a demonstration game, we show that our system can facilitate the development of network games in a fully distributed environment. [ABSTRACT FROM AUTHOR]

Our experience with using the tuple space abstraction in context-aware applications, evidenced that the traditional Linda matching semantics based on value equality are not appropriate for this domain, where queries often require the ability to match on value ranges, deal with uncertainty, and perform data aggregation. Originally developed as the core tuple space layer for the Lime middleware, LighTS provides a flexible framework that makes it easy to extend the tuple space in many ways, including changing the back-end implementation, redefining the matching semantics, and providing new constructs. In this paper, we describe the design and programming interface of LighTS, and show how its flexible architecture can be easily extended to define novel constructs supporting the development of context-aware applications. [ABSTRACT FROM AUTHOR]

While large-scale parallel/distributed simulations are rapidly becoming critical research modalities in academia and industry, their efficient and scalable implementations continue to present many challenges. A key challenge is that the dynamic and complex communication/coordination required by these applications (dependent on the state of the phenomenon being modeled) are determined by the specific numerical formulation, the domain decomposition and/or sub-domain refinement algorithms used, etc. and are known only at runtime. This paper presents Seine, a dynamic geometry-based shared-space interaction framework for scientific applications. The framework provides the flexibility of shared-space-based models and supports extremely dynamic communication/coordination patterns, while still enabling scalable implementations. The design and prototype implementation of Seine are presented. Seine complements and can be used in conjunction with existing parallel programming systems such as MPI and OpenMP. An experimental evaluation using an adaptive multi-block oil-reservoir simulation is used to demonstrate the performance and scalability of applications using Seine. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses the current resurgence of interest in the Linda coordination language for parallel and distributed programming. Particularly in the Java field, there have been a number of developments over the past few years. These developments are summarised together with the advantages of using Linda for programming concurrent systems. Some problems with the basic Linda approach are also discussed and a novel solution to these is presented. The power and flexibility of the proposed extensions to the Linda programming model are illustrated by considering a number of example applications, including a detailed case study of visual language parsing. [Copyright &y& Elsevier]

Abstract: In this paper we describe TinyLime, a novel middleware for wireless sensor networks that departs from the traditional setting where sensor data is collected by a central monitoring station, and enables instead multiple mobile monitoring stations to access the sensors in their proximity and share the collected data through wireless links. This intrinsically context-aware setting is demanded by applications where the sensors are sparse and possibly isolated, and where on-site, location-dependent data collection is required. An extension of the Lime middleware for mobile ad hoc networks, TinyLime makes sensor data available through a tuple space interface, providing the illusion of shared memory between applications and sensors. Data aggregation capabilities and a power-savvy architecture complete the middleware features. The paper presents the model and application programming interface of TinyLime, together with its implementation for the Crossbow MICA2 sensor platform. [Copyright &y& Elsevier]

In this paper, we apply market mechanism and agent to build grid resource management, where grid resource consumers and providers can buy and sell computing resource based on an underlying economic architecture. All market participants in the grid environment including computing resources and services can be represented as agents. Market participant is registered with a Grid Market Manager. A grid market participant can be a service agent that provides the actual grid service to the other market participants. Grid market participants communicate with each other by communication space that is an implementation of tuple space. In this paper, Grid agent model description is given. Then, the structure of Grid Market is described in detail. The design and implementation of agent oriented and market oriented grid resource management are presented in this paper. [ABSTRACT FROM AUTHOR]

This paper presents Xspace, a programmable coordination paradigm for Internet applications based on mobile agents. The Xspace system fully exploits the advantages of the XML language and Linda-like coordination. It supports XML documents as tuple fields and multiple matching routines implementing different relations among XML documents, including those given by XML query languages. The Xspace uses Java as the implementation language; it is based on object-oriented XMLized, tuple spaces to implement a portable and programmable coordination paradigm for mobile agents. The design and implementation procedures of Xspace are described in this paper. Experiment and performance evaluation are also made. Finally, some conclusions and remarks are given. [ABSTRACT FROM AUTHOR]