Aerospace operations face unreliable, slow networks, dynamic conditions, and expensive launches. Therefore, researchers are investigating autonomous agent architectures for space system control. However, agent systems...
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Aerospace operations face unreliable, slow networks, dynamic conditions, and expensive launches. Therefore, researchers are investigating autonomous agent architectures for space system control. However, agent systems to date lack proven reliability, scalability, and cost-effectiveness. Under the UltraLog program, the United States Defense Advanced Research Projects Agency (DARPA) has sponsored the development of the Cougaar agent architecture (open-source at http://***), a robust reusable agent framework. UltraLog used Cougaar to build a large-scale distributed prototype planning application, which was assessed under machine kills, network cuts and degradations, and increased workload. The results indicate that Cougaar agent applications would enable reliable cost-effective aerospace applications
Intra-domain traffic engineering for routing protocols such as OSPF (open shortest path first) or intermediate system-intermediate system (IS-IS) can be performed by finding a judicious set of weights to allocate to t...
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Intra-domain traffic engineering for routing protocols such as OSPF (open shortest path first) or intermediate system-intermediate system (IS-IS) can be performed by finding a judicious set of weights to allocate to the links of the network. Unfortunately, methods proposed in the literature for finding those weights may require a significant computational effort. By way of contrast, weight setting approaches based on linear programming can be shown in this paper to find suitable weights in the order of seconds. Prior to this time, it was necessary to determine appropriate weight settings in an off-line mode. From the results presented in this paper it can be demonstrated that solutions can be located for this problem in a matter of seconds. This makes it possible to perform traffic engineering for short term link overloads in real-time mode. The performance of this methodology has been verified by using simulation based on the well-known performance tool, ns-2. The technique described in this paper is being integrated into an optimisation module of a network capacity management tool called OptiFlow.
In this paper, we propose a cost-based model to evaluate the resources that each node has to contribute for participating in an overlay network. Such a cost model allows to gauge potential disincentives for nodes to c...
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In this paper, we propose a cost-based model to evaluate the resources that each node has to contribute for participating in an overlay network. Such a cost model allows to gauge potential disincentives for nodes to collaborate, and provides a measure of the "total cost" of a network, which is a possible benchmark to distinguish between different networkarchitectures. We characterize the cost imposed on a node as a parameterized function of the experienced load and of the node connectivity, and express benefits in terms of cost reductions. We discuss the notions of social optimum and Nash equilibrium with respect to the proposed cost model. We show that the social optimum may significantly deviate from a Nash equilibrium when nodes value the resources they use to forward traffic on behalf of other nodes. Through analytical and numerical results, we then use the proposed cost model to evaluate some of the topologies recently proposed for overlay networks, and to exhibit some of the challenges systems designers may face. We conclude by outlining some of the open questions this research has raised.
This paper presents an FPGA based hardware architecture, named FlexWAFE, for high resolution, high troughput real-time digital film processing. Complex algorithms require several hundred arithmetic operations per pixe...
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This paper presents an FPGA based hardware architecture, named FlexWAFE, for high resolution, high troughput real-time digital film processing. Complex algorithms require several hundred arithmetic operations per pixel which is beyond the scope of current DSP processors. To simplify programming and yet achieve high clock rates, the architecture combines component configuration with weak programmability. It alleviates the memory bottleneck by an efficient use of internal memory blocks and a multi-stream SDRAM memory scheduler with tightly bounded latency. Several examples of a discrete wavelet transform and a complex noise reducer demonstrate the architecture efficiency.
The heterogeneity and open nature of network systems make analysis of compositions of components quite challenging, making the design and implementation of robust network services largely inaccessible to the average p...
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The heterogeneity and open nature of network systems make analysis of compositions of components quite challenging, making the design and implementation of robust network services largely inaccessible to the average programmer. We propose the development of a novel type system and practical type spaces which reflect simplified representations of the results and conclusions which can be derived from complex compositional theories in more accessible ways, essentially allowing the system architect or programmer to be exposed only to the inputs and output of compositional analysis without having to be familiar with the ins and outs of its internals. Toward this end, we present the TRAFFIC (typed representation and analysis of flows for interoperability checks) framework, a simple flow-composition and typing language with corresponding type system. We then discuss and demonstrate the expressive power of a type space for TRAFFIC derived from the network calculus, allowing us to reason about and infer such properties as data arrival, transit, and loss rates in large composite network applications
EURO-NGI's main target is creating and maintaining the most prominent European centre of excellence in next generation Internet design and engineering. A specific objective of the EURO-NGI network is the developme...
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EURO-NGI's main target is creating and maintaining the most prominent European centre of excellence in next generation Internet design and engineering. A specific objective of the EURO-NGI network is the development of a Macro-Tool which provides a homogeneous environment for hosting and interrelation of the software tools developed by the research labs of the network. This paper proposes tool integration under a common user access interface as an optimal solution and proposes the Web interface as the most natural option. The paper explains several innovative aspects in the field of remote software tool execution, secure access, customized interfaces and sharing environments. WeBaSeRex is the resulting sharing environment for network planning tools based on these ideas and last sections of the paper show some concrete characteristics and application example.
The European installation bus (EIB), part of the KNX standard, is a field bus for home and building automation. Bus coupling units (BCUs) provide a generic platform for embedded nodes based on the M68HC05 microcontrol...
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The European installation bus (EIB), part of the KNX standard, is a field bus for home and building automation. Bus coupling units (BCUs) provide a generic platform for embedded nodes based on the M68HC05 microcontroller family. A set of open source tools for developing and downloading BCU programs based on the GNU tool chain is presented. It uses a RAD-like (rapid application development) approach. The tool set also supports separating application development and deployment and includes a multi-user and network-capable daemon for EIB access and network management. Issues in porting the GNU C compiler to the target platform are highlighted
This paper presents a mathematical model and a methodology to solve the transmission network expansion planning problem with security constraints in full competitive market, assuming that all generation programming pl...
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This paper presents a mathematical model and a methodology to solve the transmission network expansion planning problem with security constraints in full competitive market, assuming that all generation programming plans present in the system operation are known. The methodology let us find an optimal transmission network expansion plan that allows the power system to operate adequately in each one of the generation programming plans specified in the full competitive market case, including a single contingency situation with generation rescheduling using the security ( n -1) criterion. In this context, the centralized expansion planning with security constraints and the expansion planning in full competitive market are subsets of the proposal presented in this paper. The model provides a solution using a genetic algorithm designed to efficiently solve the reliable expansion planning in full competitive market. The results obtained for several known systems from the literature show the excellent performance of the proposed methodology.
Inter-sensor communication often comprises a significant portion of energy expenditures in a sensor network as compared to sensing and computation. We discuss an integrated approach to dynamically routing measurements...
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Inter-sensor communication often comprises a significant portion of energy expenditures in a sensor network as compared to sensing and computation. We discuss an integrated approach to dynamically routing measurements and models in a sensor network. Specifically, we examine the problem of tracking objects within a region wherein the responsibility for combining measurements and updating a posterior state distribution is assigned to a single sensor at any given time step. The so called leader node may change over time. Sensor nodes communicate for two reasons: firstly, measurements of target state are transmitted from sensors to the current leader node for incorporation into the state estimate model; secondly, the state model is transmitted between sensors when the leader node changes. The trade-off between these two types of communication is of primary importance to dynamic selection of the leader node. We propose an algorithm based on a dynamic programming roll-out formulation of the minimum cost problem. We obtain a cost function which can be efficiently minimized by simplifying the problem to that of an open loop feedback controller which is an upper bound to the optimal cost. We present empirical results which compare methods previously proposed in the literature to the algorithm presented here.
A growing part of commercial software production is provided by the so-called secondary software industry, involving both software products and services offered by other industries than the actual software industry, i...
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A growing part of commercial software production is provided by the so-called secondary software industry, involving both software products and services offered by other industries than the actual software industry, i.e. the primary industry. We have been investigating the evolution of businesses in the secondary software industry in two phases, first by developing a framework to analyse the change of host industries from closed and vertical to open and horizontal especially in terms of software products. Secondly, we have studied a set of selected industries in a pivotal era called the momentum of concurrent enterprising in this paper. The key finding is: the value creation is moving towards service offerings - which are product-based, but so that products are designed and built by the other network parties. For the OEM company it is thus essential to estimate how the market opening process will affect the success of its emerging service businesses, including the role of software products in this process.
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