Topology discovery services for monitoring the global grid

The dynamic joint optimization of both computational and network resources has the potential of guaranteeing optimal performance Io geographically distributed grid applications. A grid network information and monitoring service (NIMS) has been recently proposed to complement computational resource status information with network resource status information. NIMS information includes, but is not limited to, information already available in the network control plane (e.g., network topology, link capacity occupation, communication delay). This study first reviews some measurement methodologies and network sensors suitable for implementing NIMS components, and then describes some tools currently utilized for monitoring grid network infrastructures. Finally, two implementations of a NIMS component, called the topology discovery service (TDS), are proposed and evaluated. The TDS provides grid users (e.g., applications) or the programming environment middleware with up-to-date information on the grid network infrastructure topology and status. Both proposed implementations can be utilized in any global grid network based on commercial routers without requiring modifications of router management and control protocols.     

Leveraging component-based software engineering with Fraclet

Component-based software engineering has achieved wide acceptance in the domain of software engineering by improving productivity, reusability and composition. This success has also encouraged the emergence of a plethora of component models. Nevertheless, even if the abstract models of most of lightweight component models are quite similar, their programming models can still differ a lot. This drawback limits the reuse and composition of components implemented using different programming models. The contribution of this article is to introduce Fraclet as a programming model common to several lightweight component models. This programming model is presented as an annotation framework, which allows the developer to annotate the program code with the elements of the abstract component model. Then, using a generative approach, the annotated program code is completed according to the programming model of the component model to be supported by the component runtime environment. This article shows that this annotation framework provides a significant simplification of the program code by removing all dependencies on the component model interfaces. These benefits are illustrated with the Fractal and OpenCOM component models.     

基于领域特征本体的构件语义描述和组装

构件的功能语义是复用者了解并判断构件可复用性的重要依据，因此必须在构件开发者和复用者共同的知识基础上进行构件描述．目前已有一些方法引入本体作为构件语义描述的基础，但仍然存在语义描述不够精确以及无法支持语义的组装推导等不足．引入了领域分析中提出的基于本体的领域特征模型作为构件语义描述基础，在此基础上给出了构件端口语义、静态语义、语义协议的定义以及语义组装算法．基于构件静态语义和组装算法可以在构件组装时进行语义合成，从而辅助开发者进行基于语义的构件适配和组装分析．     

Mapping and pseudoinverse algorithms for ocean data assimilation

Among existing ocean data assimilation methodologies, reduced-state Kalman filters are a widely studied compromise between resolution, optimality, error specification, and computational feasibility. In such reduced-state filters, the measurement update takes place on a coarser grid than that of the general circulation model (GCM); therefore, these filters require mapping operators from the GCM grid to the reduced state and vice versa. The general requirements are that the state-reduction and interpolation operators be pseudoinverses of each other, that the coarse state define a closed dynamical system, that the mapping operations be insensitive to noise, and that they be appropriate for regions with irregular coastlines and bathymetry. In this paper, we describe three efficient algorithms for computing the pseudoinverse: a fast Fourier transform algorithm that serves for illustration purposes, an exact implicit method that is recommended for most applications, and an efficient iterative algorithm that can be used for the largest problems. The mapping performance of 11 interpolation kernels is evaluated. Surprisingly, common kernels such as bilinear, exponential, Gaussian, and sinc perform only moderately well. We recommend instead three kernels, smooth, thin-plate, and optimal interpolation, which have superior properties. This study removes the computational bottleneck of mapping and pseudoinverse algorithms and makes possible the application of reduced-state filters to global problems at state-of-the-art resolutions.     

通信对抗训练目标信号环境构设规划软件

通信对抗训练目标信号环境构设规划软件旨在解决基于模拟信号源的目标信号环境构设问题。简要介绍了软件的模块组成及运用方法;建立了等效逼真度评估指标并给出了评估方法和计算模型;提出了由配置位置规划、发信任务规划和动态阶段规划组成的构设规划算法;实例验证了模型和算法的可行性及软件的实用性。     

Parallel numerical applications on grid environments

Grid computing for electromagnetics is one of the few available books that present real applications running on grids. It's a practical book for researchers who want to set up a computational grid and understand the perspectives that grid computing platforms offer. It would also be suitable as a classroom text for undergraduate physics or electrical engineering students with some knowledge of computer networks, C programming, and numerical analysis.     

NRLA & MOD-Metric Models as Aids in Design Decisions

This paper reports partial results and extensions of a study at Clemson University from 1980 December to 1982 May. The purpose was to develop an integrated model set to aid in evaluating design alternatives on the availability and logistic support requirements of major weapon systems. The model set includes the Network Repair Level Analysis (NRLA) and MOD-Metric models. System design decisions concern the nominal reliability of components, the extent to which components are hierarchially designed, the accessibility of components, and whether the component will be repaired or discarded when it fails. System design includes the design of the logistic support system and its relation to the hardware. Design alternatives should be carefully investigated to determine the effects that each would have on ownership costs, performance, and availability. This model set was applied to the components of the air refueling boom of the KC-135A tanker aircraft. The 2-echelon, 2-indenture inventory system used at times by the US Air Force is assumed. In particular we report: 1) the effects of component reliability on spare stock levels and spare parts costs, and 2) the impact of component reliability on the level at which repair takes place. The models have similar data requirements and they yield useful conclusions. However, there are some difficulties. The spares decisions from MOD-Metric are not necessarily compatible with NRLA because the MOD-Metric analysis is far more sophisticated.     

GSWO: A programming model for GPU-enabled parallelization of sliding window operations in image processing

Sliding Window Operations (SWOs) are widely used in image processing applications. They often have to be performed repeatedly across the target image, which can demand significant computing resources when processing large images with large windows. In applications in which real-time performance is essential, running these filters on a CPU often fails to deliver results within an acceptable timeframe. The emergence of sophisticated graphic processing units (GPUs) presents an opportunity to address this challenge. However, GPU programming requires a steep learning curve and is error-prone for novices, so the availability of a tool that can produce a GPU implementation automatically from the original CPU source code can provide an attractive means by which the GPU power can be harnessed effectively. This paper presents a GPU-enabled programming model, called GSWO, which can assist GPU novices by converting their SWO-based image processing applications from the original C/C++ source code to CUDA code in a highly automated manner. This model includes a new set of simple SWO pragmas to generate GPU kernels and to support effective GPU memory management. We have implemented this programming model based on a CPU-to-GPU translator (C2GPU). Evaluations have been performed on a number of typical SWO image filters and applications. The experimental results show that the GSWO model is capable of efficiently accelerating these applications, with improved applicability and a speed-up of performance compared to several leading CPU-to-GPU source-to-source translators.     

基于边缘计算的数据密集型服务部署

日益增长的数据量对数据处理的要求越来越高,于是出现了数据密集型服务。在解决复杂问题时,多个数据密集型服务通常会形成一个服务组合。由于服务组件之间存在大量的数据传输,巨大的传输时延会对系统的整体性能造成影响。在边缘计算环境中,基于否定选择算法,为降低服务组合中的数据传输时间提出了一种优化部署策略。首先,给出了此类数据密集型服务组件部署问题的定义,并为该部署问题构建优化模型;然后,设计了一种否定选择算法来获取最佳的部署方案;为了评估该算法的适用性和收敛性,使用遗传算法和模拟退火算法与其对比,结果显示,提出的算法在这种数据密集型服务组件的部署问题中表现得更为出色。     

Towards a resource management and service deployment framework

Owing to the increase in both heterogeneity and complexity in today's networking systems, the need arises for new network‐based services architectures. They must provide flexibility and efficiency in the definition, deployment and execution of the services and, at the same time, handle the adaptability and evolution of such services. In this paper we present an approach that applies a Web‐service‐based resource management framework. It enables the provision of parallel applications as QoS‐aware applications, whose performance characteristics may be dynamically negotiated between a client application and service providers. Our component model allows context dependencies to be explicitly expressed and dynamically managed with respect to the hosting environment, computational resources and dependencies on other components. In such a model the resource management, in terms of representation, allocation and management of the resources, plays a vital role regarding the efficiency of the entire dynamic service deployment architecture. Copyright © 2007 John Wiley & Sons, Ltd.     

SCA4．0规范概述

软件通信体系结构（SCA）规范建立了一个与实现无关的框架,是开发软件定义无线电（SDR）软件的基本要求。SCA标准已经发布了多个版本。最新发布的SCA4．0是标准的一个重要修订。SCA4．0引入选择性继承的设计模式,实现了轻量级组件。Push模型的引入减少了启动和初始化时间,且消除了命名服务的需要。SCA4．0中不再规定CORBA是必需的中间件。SCA4．0通过分级应用和应用连通性支持在一个平台配置多个应用。SCA4．0标准可以裁剪,更好地适应每个无线电台及其功能的具体能力,比SCA2．2．2更易升级、轻量级、灵活。     

Challenges and opportunities in immersive vehicular sensing: Lessons from urban deployments

Vehicles provide an ideal platforms for a plethora of emerging applications such as networked gaming, multimedia content delivery and urban sensing. Cars have no power constraints and they can be instrumented with high end computational units and graphic devices. The deployment at scale of urban vehicular systems, however, requires a careful design able to consider challenges across several domains. Vehicular systems are arguably a prominent example of cyber-physical systems. The development of such systems requires a truly multidisciplinary approach and a close integration between the application, communication, and physical domains. Hardware and software mounted on vehicles will face a harsh physical and communication environment that will greatly affect all the system components. In this paper we report on the challenges and opportunities for multimedia vehicular urban sensing systems based on our field experiences in Macao (China) and Los Angels (USA). We designed and built the components for a pollution monitoring system able to support closed-loop optimization between pollution and traffic management. Our initial set of prototype vehicles are now running in the city of Macao and they are measuring the air parameters as well as the urban traffic. The paper aims at exposing some of the issues encountered, outlining the problems of a city wide deployment, and augmenting our in-field experience with the results from large scale simulation studies.     

Optimal replacement policies for k-out-of-nsystems

The authors study a discrete-time, infinite-horizon, dynamic programming model for the replacement of components in a binary k -out-of-n:F system. The goal is to trade off the component replacement and system failure costs. Under the criterion of minimizing the long-run average cost per period, it is optimal to follow a critical component policy (CCP), viz., a policy specified by a critical component set and the rule: replace a component if and only if it is failed and is in the critical component set. Computing an optimal CCP is a binary nonlinear programming problem, which can be solved by searching through a set with O(n^k-1) points. This approach to finding an optimal CCP is practical when k is small. In particular, assuming s-independent components, it requires O(n^2k-1) calculations. The authors analyze in detail the two most important cases with small k: the series (1-out-of-n:F) system and the 2-out-of-n:F system     

支持网络动态重构的可信构件模型

基于构件接口分离原则和动态软件体系结构技术,提出了一种支持网络动态重构的可信构件模型,对构件构造和组装进行了分析,并提出了可信数据安全封装机制。基于感知、决策和执行分离机制,构件模型可以支持构件重构,通过容器对构件数据进行安全封装,构件模型可以检测和阻止恶意构件的非法操作,保护构件间的数据安全传递。实现了支持可信构件模型的容器原型,实验表明,使用该模型可进行构件连接拓扑关系的重构,可及时发现恶意构件并暂停构件运行,提高了节点的可信性。     

Decision support and disease management: a logic engineeringapproach

This paper describes the development and application of PROforma, a unified technology for clinical decision support and disease management. Work leading to the implementation of PROforma has been carried out in a series of projects funded by European agencies over the past 13 years. The work has been based on logic engineering, a distinct design and development methodology that combines concepts from knowledge engineering, logic programming, and software engineering. Several of the projects have used the approach to demonstrate a wide range of applications in primary and specialist care and clinical research. Concurrent academic research projects have provided a sound theoretical basis for the safety-critical elements of the methodology. The principal technical results of the work are the PROforma logic language for defining clinical processes and an associated suite of software tools for delivering applications, such as decision support and disease management procedures. The language supports four standard objects (decisions, plans, actions, and enquiries), each of which has an intuitive meaning with well-understood logical semantics. The development tool set includes a powerful visual programming environment for composing applications from these standard components, for verifying consistency and completeness of the resulting specification and for delivering stand-alone or embeddable applications     

A development and runtime platform for teleconferencingapplications

A communication platform is described that supports the fast implementation of networked multimedia applications with conference character and collaboration features. The platform exhibits the notion of a site as one of its main abstractions. A site is a collection of workstations, media input, and output devices that are, in terms of control, tightly coupled. Connection and application control is centralized within one site, but distributed among different sites. The platform exports a programming interface with high-level abstractions for session and connection control, allowing application developers to concentrate on scenario and user interface design. The platform was implemented in the course of the European Beteus (Broadband Exchange for Trans-European Usage) project. A tele-meeting application and a tele-teaching application were developed on top of it. Platform components and applications were tested on the European asynchronous transfer mode (ATM) pilot network over a period of nine months. The paper first describes platform architecture and programming interface, then talks about the implementation of platform and applications and their deployment in the harsh environment of a trans-national broadband pilot network     

Optimal component configuration and component routing

Code mobility and mobile agents have received a lot of attention as a paradigm based on which distributed applications can be built. There has been little work however on the mathematical modeling of component mobility. In this direction, we present and analyze three optimization models for component mobility. We are seeking the optimal allocation of components to network nodes and the optimal component routes that will minimize the network traffic that is incurred in the course of component communication. Optimal solutions are found either through a mixed binary integer programming formulation or by employing max flow computations. Complexity results are also reported.     

一种支持变化性的构件模型JBCOM/E

在基于构件的软件开发中,构件模型是基础,领域变化性是关键因素之一.为此,本文在原有构件模型的基础上,提出了抽象构件的概念,使之能对一族具有领域共性和变化性的构件进行定义与描述.文中就抽象构件的定义、规约语言描述以及相应的构件组装和构件管理等问题进行了讨论,定义了一种支持变化性的构件模型JBCOM/E,并给出了一个应用实例-青鸟POS领域平台.     

Construction of isothetic covers of a digital object: A combinatorial approach

An isothetic cover of a digital object not only specifies a simple representation of the object but also provides an approximate information about its structural content and geometric characteristics. When the cover “tightly” encloses the object, it is said to be an outer isothetic cover; and when the cover tightly inscribes the object, it is an inner isothetic cover. If a set of horizontal and vertical grid lines is imposed on the object plane, then the outer (inner) isothetic cover is defined by a set of isothetic polygons, having their edges lying on the grid lines, such that the effective area corresponding to the object is minimized (maximized). Increasing or decreasing the grid size, therefore, decreases or increases the complexity or the accuracy of the isothetic cover corresponding to a given object, which, in turn, extracts the object information at different resolutions. In this paper, a combinatorial algorithm is presented for varying grid sizes, which is free of any backtracking and can produce the isothetic cover of a connected component in a time linear in the length of the perimeter of the cover. The algorithm has also been extended for finding the isothetic covers of real-world digital objects having multiple components with or without holes. Experimental results that demonstrate applications of an isothetic cover to diverse problems of pattern analysis and computer vision, are reported for various data sets.     

Teaching Condor Grid Computing to Beginning Programming Students

Grid computing is taught at the University of Arkansas, focusing on the development of grid services, the Globus toolkit, and higher-level grid components. An early course, cluster and grid computing, successfully taught Globus materials to advanced undergraduates and beginning graduate students. However, the material assumed advanced knowledge of Java programming and covered networking and basic distributed systems concepts, and was therefore too advanced for beginning programming students. When teaching grid computing to beginners, we must focus on creating and submitting a grid job rather than programming grid services. We also teach grid computing to advanced science and engineering students whose programming skills are similar to those of beginning computer science students