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The scheduling of the design activities in product development process is a crucial step in early stages in order to achieve the project in time and cost-effective manner. In complex product development process, many dependency relationships or feedback loop could exist between design activities with multiple technical domains. Sequencing the design activities is a decision making process in order to reduce these feedback loops, and therefore, reduce amount of required information flows between activities. In recent years, methods for sequencing the design activities in design process have been proposed in order to reduce lead-time development and cost. The purpose of this research work is to present a methodology for design process sequencing in product development project by using Design Structure Matrix (DSM) for visualization a complex process and Discrete Differential Evolution (DDE) for sequencing the design tasks. The tests performed in this article have shown that this approach provides very competitive results in term of the quality of obtained solutions when compared to Genetic algorithms (GA). In additional it is a simple, effective and easy to use since the amount of control parameters to set is reduced.Copyright © 2012 by ASME

Recent studies have shown that to improve the performance of specific System-on-Chip (SoC) application domain, the OCI (On-Chip Interconnect) architecture must be customized, at design time. These approaches are generally tailored to a specific application, providing an application-specific SoC. They deal with the selection of OCI architecture to accommodate the expected applicationspecific data traffic pattern during early design-space exploration phase. For dynamic SoCs, in which traffic pattern of applications is not known or predictable in advance, an efficient OCI is required. In this paper, we present an approach to allow designers to customize a candidate OCI architecture in order to match large application workload. Simulations results, using 2D mesh, show that this method achieves better performance compared to the basic 2D mesh OCI architecture, while using little resource budget.

Network-on-chip (NoC) has been proposed for SoC (System-on-Chip) as an alternative to on-chip bus-based interconnects to achieve better performance and lower energy consumption. Several approaches have been proposed to deal with NoCs design and can be classified into two main categories, design-time approaches and run-time approaches. Design-time approaches are generally tailored for an application domain or a specific application by providing a customized NoC. All parameters, such as routing and switching schemes, are defined at design time. Run-time approaches, however, provide techniques that allow a NoC to continuously adapt its structure and its behavior (i.e., at runtime). In this paper, performance evaluation of a flow control algorithm for congestion avoidance in NoCs is presented. This algorithm allows NoC elements to dynamically adjust their inflow by using a feedback control-based mechanism. Analytical and simulation results are reported to show the viability of this mechanism for congestion avoidance in NoCs.

Network-on-Chip (NoC) architectures were proposed to solve scalability issues experienced in bus-based SoCs. They incorporate a communication infrastructure defined by topology, routers and switches, in order to provide a scalable and high performance network for the SoC resources while satisfying the constraints of embedded platforms. The choice of appropriate NoC topology depends on the desired network size for the required performance. Simulation of NoCs based on real application traffic is time consuming, and therefore not a feasible approach for rapid design space exploration. In this paper, a methodology to study the scalability of three on-chip interconnect architectures, WK-recursive, Mesh and Spidergon, is presented. Simulation results are presented for different cases, demonstrating the potential of our approach for selecting the most scalable on-chip interconnect architecture.

It is described an abstract model for the definition and the dynamic evolution of "communities of actants" originating from a given reference society of roles. Multiple representations are provided, showing how communities evolve with respect to their reference societies. In particular we show how such representations are self-similar and factorisable into "prime" constituents. An operating model is then introduced that describes the life-cycle of the communities of actants. After this a software component is presented-the service-oriented community-and its features are described in terms of the above mentioned models. Finally it is shown how such component can constitute the building block of a novel architecture for the design of fractal social organizations.

Rapid advances in technology and design tools enabled today engineers to design system-on-chip containing large number of cores. These systems have limited resources and should be implemented with very little silicon area overhead. Several studies have demonstrated that buffers inside switches of the on-chip interconnect take a significant portion of the system silicon area that can affects the performance and the energy consumption. Therefore, their size should be carefully customized to match communication patterns of a target application. In this paper, a compartmental Fluid-flow based modeling approach is presented to allocate required resource for each buffer based on the application traffic pattern. Simulations are conducted and preliminary results are reported to show the efficiency of the Fluid-flow based modeling method for a buffer space allocation.

Network-on-Chip (NoC) has been proposed as an alternative to bus-based schemes to achieve high performance and scalability in System-on-Chip (SoC) design. Performance analysis and evaluation of on-chip interconnect architectures are widely based on simulations, which become computationally expensive, especially for large-scale NoCs. In this paper, a Network Calculusbased methodology is presented to analyze and evaluate the performance and cost metrics, such as latency and energy consumption. The 2D Mesh, Spidergong, and WK-recursive on-chip interconnect architectures are analyzed using this methodology and results are compared with those produced using simulations. The values obtained by simulations and by analysis show similar trends in the same order of magnitude. Furthermore, WK outperforms the other on-chip interconnects in all considered metrics.

Network-on-chip (NoC) architectures adopted for System-on-Chip (SoC) are characterized by different trade-offs between latency, throughput, communication load, energy consumption, and silicon area requirements. Evaluating NoC architectures is usually performed using simulations which provide little insight on how different design parameters affect the actual NoC performance metrics. Analytical models that allow rapid trade-off investigations of NoC parameters and accelerate the estimation of main metrics are required. In this paper, a Network Calculus-based methodology is presented to analyze and evaluate the performance metrics such as the latency and the cost metrics such as the energy consumption of NoC-based architectures. The WK-recursive on-chip interconnect is analyzed and results are compared against those produced using simulations. The values obtained by simulations and by analysis show the same increasing/decreasing trends in the same order of magnitude.

Inter-Vehicles Networks (IVNs) have emerged as a new environment for intelligent transportation applications. The implementation of these applications requires dealing with many issues. The design and the implementation of an efficient and scalable architecture for information dissemination constitute one major issue. In this paper, a decentralized architecture inspired by stigmergy and direct communication between Ants is presented. The Ants colony has a set of organizing principles, such as scalability and adaptability that are useful for developing a decentralized architecture in highly dynamic networks. Simulations are conducted using Starlogo simulator and some metrics such as information relevance and drivers' awareness are evaluated. Preliminary results are reported to first show the effectiveness of the proposed information dissemination strategy.

Ubiquitous and pervasive computing are recent paradigms with a goal to provide computing and communication services anytime and everywhere. In ubiquitous computing, the main objective is to provide users the ability to access services and resources all the time and irrespective to their location, while in pervasive computing, the main objective is to provide spontaneous emergent services created on the fly by mobiles that interact by ad hoc connections. The design and development of ubiquitous and pervasive applications require new protocols and architectures to efficiently use resources and services. Gaber's classification of interaction paradigms emphasizes two alternative paradigms to the traditional client-to-server paradigm (CSP) to design and implement Ubiquitous and Pervasive applications, which are the Adaptive Services-to-Client Paradigm (SCP) and the Spontaneous Service Emergence Paradigm (SEP). These paradigms involve context awareness, auto-adaptive and emergence principles that could be implemented by self-organizing and reactive intelligent networks.Approaches and protocols that are mainly proposed to meet these requirements can be classified into two major research directions. The first direction addresses semantic languages to specify and describe application components, including complex planning mechanisms that utilize these descriptions to generate the whole application or composite service. The second direction aims to develop architectures that enable scalable, fault tolerance, and adaptive applications in dynamic environments. This talk will survey current approaches and protocols proposed to design and built ubiquitous and pervasive applications. We will present service-oriented architecture principles with service description languages. We will also highlight new research directions that can leverage the tremendous potential of this new category of applications.

VANETs are emerging as new network environments for developing future automotive applications. Numerous research issues have recently been identified and should be tackled before real implementations of pervasive vehicular applications and services. The design and the implementation of efficient and scalable routing protocols constitute one main issue. In this paper, we study and evaluate the performance of a geographical protocol in VANETs using real vehicle mobility scenarios. Performance metrics such as the control load and the average latency are evaluated using ns2.

Network-on-Chip (NoC) has been proposed as an alternative to bus-based schemes to achieve high performance and scalability in System-on-Chip (SoC) design. Performance evaluation of On-Chip Interconnect (OCI) architectures is widely based on simulation which becomes computationally expensive, especially for large-scale NoCs. In this paper, a performance analysis model using Network Calculus is presented to characterize and evaluate the performance of NoC-based applications. The 2D Mesh on-chip interconnect is analyzed and main performance metrics such as end-to-end delay and buffer size requirements are computed and compared against the results produced by a discrete event simulator. The results shed more light on the potential of this analytical technique as a useful tool for NoC design and performance analysis.

Position-based routing protocols were recently proposed as a solution to non-scalable topology-based routing protocols for large scale mobile ad hoc networks. In these position-based routing protocols, nodes may not maintain explicit routes. Each node needs only to know its own position and the position of its one-hop neighbors to forward packets. In this paper, a performance evaluation of the position-based routing protocol DREAM for large scale ad hoc networks is presented. Several performance metrics such as the control load and the average latency are evaluated using ns2 for up to 500 nodes generated according to the realistic mobility model RealMobgen.

Peer-to-peer networks are distributed computing infrastructures that can provide globally available network resources. Their size and complexity continue to increase and permit an almost ubiquitous availability of resources. Therefore, new discovery approaches are required and need to be highly flexible in order to cope with a dynamically changing environment. In this paper, a distributed agent-based approach for resource discovery in peer-to-peer network is proposed. This approach is based on the mobile agent paradigm and uses random walks to allow dynamic and adaptive resource discovery. We analyze this approach through three distributed resource discovery scenarios by NS2 simulator.

The design and development of ubiquitous and pervasive applications require new operational models that can permit an efficient use of resources and services and a reduction of the need for the administration effort typical in client-to-server networks. In ubiquitous computing, the main objective is to provide users the ability to access services and resources all the time and irrespective to their location, while in pervasive computing, the main objective is to provide spontaneous emergent services created on the fly by mobiles that interact by ad hoc connections. Service discovery and composition in ubiquitous and pervasive environments requires dealing with several issues such as service matching and selection, coordination and management, scalability, fault tolerance, and adaptive approaches to users' contexts and network conditions. Gabers' classification of interaction paradigms emphasizes two alternative paradigms to the traditional client-to-server paradigm (CSP) to design and implement Ubiquitous and Pervasive applications, which are the Adaptive Services-to-Client Paradigm (SCP) and the Spontaneous Service Emergence Paradigm (SEP). These paradigms involve context awareness, auto-adaptive and emergence principles that could be implemented by self-organizing and reactive intelligent networks.This talk will survey the service discovery and composition methods. We will present the service-oriented architecture principles with service description languages, in particular, syntactic and semantic description languages and ontologies. We will demonstrate how to develop applications that suit ubiquitous and pervasive environments. We will also highlight new research directions that can leverage the tremendous potential of this new category of applications.

Network-on-chip has been proposed as an alternative to bus-based system to achieve high performance and scalability. The topology of on-chip interconnect plays a crucial role in system on chip performance, energy, and area requirements. In this paper, an on-chip interconnects architecture based on WK-recursive network is proposed. WK-recursive structure is analyzed and compared to 2D mesh and Spidergon structures. Simulation results show that WK-recursive on-chip interconnect generally outperforms the other architectures.

On-chip interconnect (OCI) plays a prime role in the entire system-on-chip performance, energy consumption, and area requirements. OCI has become a successful research field given the dramatic increase in the number of processors and other functional units (IPs) that need to be integrated on a single chip. Current systems-on-chip (SoCs) use bus- based systems which become a bottleneck because of scalability, energy efficiency and frequency limitations. New sophisticated interconnects were recently proposed as a re search direction in SoC design, including distinct topologies and specific routing and switching techniques. This paper analyzes and compares five common NoC configurations, 2D mesh, ring, spidergon, fat-tree(FT) and butterfly fat-tree (BFT). These configurations are simulated for different traffic scenarios that imitate certain application domains, and comparison results for different performance metrics are presented.

Finding the Longest Common Subsequence (LCS) is a traditional and well studied problem in bioinformatics and text editing. In this paper, a customized parallel algorithm based on the Partitioned Global Address Space (PGAS) programming model to compute the LCS is presented. The algorithm is based on two related parameters balancing the communication and the synchronization needs in order to find the best data and workload distributions. The basic design of the algorithm and its complexity analysis are discussed together with experimental results. These results show the impact of those parameters on PGAS algorithm performance.

In many pervasive applications, such as information sharing, a user is much more likely to communicate and interact with other users having similar interests. Therefore, an approach based on the creation of communities composed of users with similar preferences and interests is required to promote computer-based human interactions. In this paper, a reinforcement learning-based approach by mimicking the human immune system behavior for the implementation of pervasive applications is presented. In this model, services or user interests are represented by agents that can establish relationships based on affinities to create a spontaneous propitient multi-agent system. Affinity corresponds to the adequacy with which two services could bind to share common interest attributes. These affinities are adjusted or reinforced by users' satisfaction regarding their interaction and dynamic network condition changes. Simulation of this proposed service emergence model is also presented.

Many new Partitioned Global Address Space (PGAS) programming languages have recently emerged and are becoming ubiquitously available on nearly all modern parallel architectures. PGAS programming languages provide ease-of-use through a global shared address space while emphasizing performance by providing locality awareness and a partition of the address space. Examples of PGAS languages include the Unified Parallel C (UPC), Co-array Fortran, and Titanium languages. Therefore, the interest in complexity design and analysis of PGAS algorithms is growing and a complexity model to capture implicit communication and fine-grain programming style is required. In this paper, a complexity model is developed to characterize the performance of algorithms based on the PGAS programming model. The experimental results shed further light on the impact of data distributions on locality and performance and confirm the accuracy of the complexity model as a useful tool for the design and analysis of PGAS-based algorithms.

Future distributed computing systems will be ubiquitous and provide accesses to a wide range of services at any time, every where, and from a variety of devices. The monitoring and controlling accesses to services are one of the fundamental challenges that must be faced in the context of ubiquitous and pervasive environments. To address services accesses issues, it is necessary to guaranty the user access to utilize the allowed and available services. More precisely, an access control must be granted to services in order to regulate their usage. In this paper, a contract-based approach for monitoring and controlling accesses to services in ubiquitous environments is presented. In this approach, client agents and server agents are bounded by contracts: the server agent expects that the client agent will not attempt to access other services than those it required, and the client agent expects that the server agent will provide the required service.

Mobile agent is a progrant that can migrate from a machine to another in a network and perform tasks on machines that provide agent hosting capability. The agent can clone itself in order to increase system robustness and efficiency. The clone operation creates multiple instances of an agent to run on different machines. However, increasing agent population size, with cloning operation, will increase resource demands in the network, which would indirectly affect network performance. When, the mobile agents operate in a dynamic and distributed environment, it is difficult to estimate a priori the appropriate number of agents allowed to be spawned in the network. This paper focuses on the problem of dynamic regulation of mobile agent population size in a distributed system, and proposes an approach that takes inspiration from the immune system concept.

In this paper, a distributed and adaptive approach for resource discovery in peer-to-peer networks is presented. This approach is based on the mobile agent paradigm and the random walk technique with reinforcement learning to allow for dynamic and self-adaptive resource discovery. More precisely, this approach augments random walks with a reinforcement learning technique where mobile agents are backtracked over the walked path in the network. A metric recording an affinity value that incorporates knowledge from past and present searches is maintained between nodes. The affinity value is used during a search to influence the selection of the next hop. This approach is evaluated with the network simulator ns2.

Very large scale networks such as the Internet require a new operational model to use resources efficiently and reduce the need for the administration necessary in client-server networks. In this paper, we present an autonomous decentralised system based on mobile agent paradigm and inspired by the immune system as an alternative to the traditional client-server paradigm. The immune system has a useful set of organising principles that guide the design of scale, adapt and efficient enough networking model to bring answers to some large scale networking challenges. This research is the part of an effort to develop a mobile agent-based middleware that can monitor the resources distributed over a large scale networks.

In this paper, we analyze the performance of a mobile agent based approach for discovering and allocating resources in large scale networks. We compare this approach with the traditional client/server approach by considering four scenarios for processing requests in the distributed network.

Very large scale networks such as the Internet require a new operational model to use resources efficiently and reduce the need for the administration necessary in client-server networks. In this paper, we present an autonomous decentralized system inspired by the immune system as an alternative to the traditional client-server paradigm. The immune system has a useful set of organizing principles that guide the design of scale, adapt and efficient enough networking model to bring answers to some large scale networking challenges.

Product development is a challenging activity. The process begins with a description and representation of a design problem in form of a requirements document. It involves two phases: elicitation by description in Natural Language (NL) and clarification of the description. NL implies interpretation of terms within a context to avoid later misunderstanding. The paper proposes a methodology to elicit and refine the initial needs. The elicitation is done by finding support information from several sources such as patent databases, encyclopaedias and commercial websites. The refinement supported by a computer-based approach is done on different levels (grammar, words and context selection) to reduce the ambiguity of the requirements descriptions. The initial description is refined by an automatic questioning process. This is followed by an assisted search and selection of answers from different web-based sources. Relevant answers are selected using a similarity metric. A case study is used to demonstrate the approach.

Web services are currently used by organizations to share their knowledge over the network and facilitate business to-business collaboration. However, combining Web services to satisfy user requests is a complex process. Workflow patterns are widely used for Web service composition to allow the specification of composite services. In this paper, the performance evaluation and analysis of workflow patterns is presented. We use both (max, +) algebra and Petri Nets as formal modeling tools to describe the behavior of workflow patterns and analyze their properties and performances. A real case study is worked out to represent and study the performances of integrated workflow patterns.

Information broadcasting in MANETs is an essential building block for cooperative operations, group discussions, and common announcements (e.g., filling routing tables). The flooding is the simplest broadcasting scheme used in MANETs. In this scheme, source nodes broadcast at once packets to all neighbors. Broadcasting through flooding causes increased messages redundancy, collision, and wastage of bandwidth and energy. Several approaches have been proposed to solve these issues and could be classified into two main categories: static schemes and adaptive schemes. In this paper, we introduce an adaptive scheme for information broadcasting in MANETs. This scheme allows nodes to select an appropriate action, either to rebroadcast or to discard receiving messages. The decision is based on the amount and timestamps of received messages. Simulations have been conducted and results show that the proposed scheme reduces the number of packet transmissions, has better latency and SRB, good reachability, and low energy consumption.

Large scale networks such as computational Grid is a distributed computing infrastructure that can provide globally available network resources. Their size and complexity continue to increase and permit an almost ubiquitous availability of resources; users become able to access network resources irrespective to their location. Therefore, new resource management and access models are required and need to be highly flexible with self-organizing capabilities in order to cope with a dynamically changing environment. In this paper, a distributed and adaptive holonic multi-agent system for resource discovery in Grids is presented. Simulations are presented to demonstrate that structuring servers into holons improves the performance of request resolution processes in dynamic Grid environment.

Engineering large-scale Cyber-Physical Systems - like robot swarms, augmented crowds, and smart cities - is challenging, for many issues have to be addressed, including specifying their collective adaptive behaviour and managing the connection of the digital and physical parts. In particular, some approaches propose self-organising mechanisms to actually program global behaviour while fostering decentralised, asynchronous execution. However, most of these approaches couple behavioural specifications to specific network architectures (e.g., peer-to-peer), and therefore do not promote flexible exploitation of the underlying infrastructure. Conversely, pulverisation is a recent approach that enables self-organising behaviour to be defined independently of the available infrastructure while retaining functional correctness. However, there are currently no tools to formally specify and verify concrete architectures for pulverised applications. Therefore, we propose to combine pulverisation with multi-tier programming, a paradigm that supports the specification of the architecture of distributed systems in a single code base, and enables static checks for the correctness of actual deployments. The approach can be implemented by combining the ScaFi aggregate computing toolchain with the ScalaLoci multi-tier programming language, paving the path to support the development of self-organising cyber-physical systems, addressing both functional (behaviour) and non-functional concerns (deployment) in a single code base and modular fashion.

Context. Self-organising and collective computing approaches are increasingly applied to large-scale cyber-physical systems (CPS), enabling them to adapt and cooperate in dynamic environments. Also, in CPS engineering, digital twins are often leveraged to provide synchronised logical counterparts of physical entities, whereas in sensor networks the different-but-related concept of virtual device is used e.g. to abstract groups of sensors. Vision. We envision the design concept of 'augmented collective digital twin' that captures digital twins at a collective level extended with purely virtual devices. We argue that this concept can foster the engineering of self-organising CPS by providing a holistic, declarative, and integrated system view. Method. From a review and proposed taxonomy of logical devices comprehending both digital twins and virtual devices, we reinterpret a meta-model for self-organising CPSs and discuss how it can support augmented collective digital twins. We illustrate the approach in a crowd-aware navigation scenario, where virtual devices are opportunistically integrated into the system to enhance spatial coverage, improving navigation capabilities. Conclusion. By integrating physical and virtual devices, the novel notion of augmented collective digital twin paves the way to self-improving system functionality and intelligent use of resources in self-organising CPSs. Conclusion. By integrating physical and virtual devices, the novel notion of augmented collective digital twin paves the way to self-improving system functionality and intelligent use of resources in self-organising CPSs.

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