PIVOT: An adaptive information discovery framework for computational grids

In a traditional computational grid environment, the owners of resources usually provide information about their resources extracted by pre-configured information services or web services. However, such information is not sufficient for the scheduler in the high-performance distributed computing. To solve this problem, we propose a scalable grid information service framework, named PIVOT (adaPtive Information discoVery framewOrk for compuTational grid). By using deadline-constrained flooding collector dissemination and P2P-like information collection schemes, PIVOT provides an active mechanism to collect application-specific resource information. In particular, PIVOT provides a resource information service for application-specific schedulers. The best-effort performance on overhead traffic and communication latency during information discovery is guaranteed by two new distributed cooperative algorithms. The experimental results in the simulations and real computational grid platform demonstrate that PIVOT has a high level of adaptability for application-specific resource information discovery, and also improves the accuracy of resource allocation and the efficiency of executing parallel tasks in traditional information services.     

Advanced networking services for distributed multimedia streaming applications

Increased network speeds coupled with new services delivered via the Internet have increased the demand for intelligence and flexibility in network systems. This paper argues that both can be provided by new hardware platforms comprised of heterogeneous multi-core systems with specialized communication support. We present and evaluate an experimental network service platform that uses an emergent class of devices—network processors—as its communication support, coupled via a dedicated interconnect to a host processor acting as a computational core. A software infrastructure spanning both enables the dynamic creation of application-specific services on the network processor, mediated by middleware and controlled by kernel-level communication support. Experimental evaluations use a Pentium IV-based computational core coupled with an IXP 2400 network processor. The sample application services run on both include an image manipulation application and application-level multicasting.

Trusted Directory Services for Secure Internet Connectivity: Transport Layer Security using DNSSEC

The Internet today is a highly dynamic environment which frequently requires secure communication between peers that do not have a direct trust relationship. Current solutions for establishing trust often require static and application-specific Public Key Infrastructures (PKIs). This paper presents trusted directory services as a key infrastructural technology for setting up secure Internet connections, providing an alternative to application-specific PKIs. The directory securely binds public keys to peers through their names in a flexible way that matches the dynamic nature of the Internet. We elaborate on this concept by showing how the Domain Name System (DNS) and its security extensions (DNSSEC) can be leveraged for establishing secure Transport Layer Security (TLS) connections in a dynamic way. A simple enhancement of the TLS protocol, called Extended TLS (E-TLS), required for this purpose, is proposed. We describe our E-TLS implementation and we conclude with an evaluation of our results.     

A fuzzy RISC processor

We describe application-specific extensions for fuzzy processing to a general purpose processor. The application-specific instruction set extensions were defined and evaluated using hardware/software codesign techniques. Based on this approach, we have extended the MIPS instruction set architecture with only a few new instructions to significantly speed up fuzzy computation with no increase of the processor cycle time and with only minor increase in chip area. The processor is implemented using a reconfigurable processor core which was designed as a starting point for application-specific processor designs to be used in embedded applications. Performance is presented for three representative applications of varying complexity     

Mica: a wireless platform for deeply embedded networks

Low-power integration of sensing, communication, and computation requires a new approach to wireless design. Flexible interfaces and primitive accelerators enable aggressive system-level optimizations. Mica's flexible design serves as a building block for creating efficient application-specific protocols. Instead of defining narrow, standardized application interfaces, Mica provides a set of richly interconnected primitives (such as data serializers and timing extractors) to facilitate cross-layer optimizations. To explore novel systems approaches, researchers can develop customized protocols tailored to their application; Mica does not require use of predefined protocols.     

Customized Message Passing

Replacing traditional operating systems communication implementations with customized implementations increases the performance of parallel and distributed applications. This paper describes the design and implementation of customizable message passing systems. The customized message passing systems are generated using application-specific information such as the profile of an application's communication pattern. FFT, Simplex, and Cholesky are used as example parallel applications. The message passing system has also been customized for different types of distributed system services including a distributed scheduling facility. The customized message passing system likewise improves the performance of these facilities and enhances their scalability. As a practical concern, as there are a large number of possible optimizations, object-oriented frameworks are employed to organize the implementations and to facilitate the choice of optimizations.     

Improving collision avoidance for mobile robots in partially known environments: the beam curvature method

This paper presents a new approach to obstacle avoidance for mobile robots in cluttered and unknown or partially unknown environments. The method combines a new directional method, called beam method (BM), to improve the performance of a local obstacle avoidance approach called curvature velocity method (CVM). BM calculates the best one-step heading which is used by CVM to obtain the optimal linear and angular velocities. The resulting combined technique is called beam curvature method (BCM).

Different experiments in populated and dynamic environments have proved to be very successful. The method is able to guide the robot safely and efficiently during long time periods. We present some of these results compared with other methods.     

An application-semantics-based relaxed transaction model for internetware

An internetware application is composed by existing individual services, while transaction processing is a key mechanism to make the composition reliable. The existing research of transactional composite service (TCS) depends on the analysis to composition structure and exception handling mechanism in order to guarantee the relaxed atomicity. However, this approach cannot handle some application-specific requirements and causes lots of unnecessary failure recoveries or even aborts. In this paper, we propose a relaxed transaction model, including system mode, relaxed atomicity criterion, static checking algorithm and dynamic enforcement algorithm. Users are able to define different relaxed atomicity constraint for different TCS according to application-specific require- ments, including acceptable configurations and the preference order. The checking algo- rithm determines whether the constraint can be guaranteed to be satisfied. The enforce- ment algorithm monitors the execution and performs transaction management work ac- cording to the constraint. Compared to the existing work, our approach can handle com- plex application requirements, avoid unnecessary failure recoveries and perform the transaction management work automatically.     

核向量机与支持向量机相结合的二阶段快速学习方法

支持向量机(SVM)作为一种有效的模式分类方法,当数据集规模较大时,学习时间长、泛化能力下降;而核向量机(CVM)分类算法的时间复杂度与样本规模无关,但随着支持向量的增加,CVM的学习时间会快速增长。针对以上问题,提出一种CVM与SVM相结合的二阶段快速学习算法(CCS),首先使用CVM初步训练样本,基于最小包围球(MEB)筛选出潜在核向量,构建新的最有可能影响问题解的训练样本,以此降低样本规模,并使用标记方法快速提取新样本;然后对得到的新训练样本使用SVM进行训练。通过在6个数据集上与SVM和CVM进行比较,实验结果表明,CCS在保持分类精度的同时训练时间平均减少了30%以上,是一种有效的大规模分类学习算法。     

Usability methods’ familiarity among map application developers

Developments in hardware and software have led to new innovative methods for visualising geospatial data. At the same time user-centred design (UCD) and usability engineering methods have a fundamental role in designing applications for new technical environments, which involve entirely new ways of interacting. However, applying methods from other research disciplines may not always be straightforward, as the product developers have to operate in a challenging interdisciplinary field. The aim of this study was to find out how usability engineering is currently included in the development of map services. Seven companies developing different types of map applications in Finland were interviewed. The results support the suitability of usability engineering for map application design, since by including the usability approach into the product design, while simultaneously taking into account the individuality and diversity of users and their tasks together with the characteristics of the maps, application developers are more likely to design products that have a higher quality of use. This study identifies the main occasions when the usability approach could be most beneficial. Furthermore, the benefits and challenges of including usability approaches in map application design are discussed. Preliminary ideas on what usability means in the context of map applications are also given. Finally, the importance for providing a basis for the further development of application-specific guidelines and techniques is addressed.     

Toward effective service composition for real-time SOA-based systems

Many application domains are increasingly leveraging service-oriented architecture (SOA) techniques to facilitate rapid system deployment. Many of these applications are time-critical and, hence, real-time assurance is an essential step in the service composition process. However, there are gaps in existing service composition techniques for real-time systems. First, admission control is an essential technique to assure the time bound for service execution, but most of the service composition techniques for real-time systems do not take admission control into account. A service may be selected for a workflow during the composition phase, but then during the grounding phase, the concrete service may not be able to admit the workload. Thus, the entire composition process may have to be repeated. Second, communication time is an important factor in real-time SOA, but most of the existing works do not consider how to obtain the communication latencies between services during the composition phase. It is clear that maintaining a full table of communication latencies for all pairs of services is infeasible. Obtaining communication latencies between candidate services during the composition phase can also be costly, since many candidate services may not be used for grounding. Thus, some mechanism is needed for estimating the communication latency for composite services. In this paper, we propose a three-phase composition approach to address the above issues. In this approach, we first use a highly efficient but moderately accurate algorithm to eliminate most of the candidate compositions based on estimated communication latencies and assured service response latency. Then, a more accurate timing prediction is performed on a small number of selected compositions in the second phase based on confirmed admission and actual communication latency. In the third phase, specific concrete services are selected for grounding, and admissions are actually performed. The approach is scalable and can effectively achieve service composition for satisfying real-time requirements. Experimental studies show that the three-phase approach does improve the effectiveness and time for service composition in SOA real-time systems. In order to support the new composition approach, it is necessary to effectively specify the needed information. In this paper, we also present the specification model for timing-related information and the extension of OWL-S to support this specification model.     

An analysis of cache performance for a hypercube multicomputer

Multicomputer cache simulation results derived from address traces collected from an Intel iPSC/2 hypercube multicomponent are presented. The primary emphasis is on examining how increasing the number of processor nodes executing a parallel application affects the overall multicomputer cache performance. The effects on multicomputer direct-mapped cache performance of application-specific data partitioning, data access patterns, communication distribution, and communication frequency are illustrated. The effects of system accesses on total cache performance are explored, as well as the reasons for application-specific differences in cache behavior for system and user accesses. Comparing user code results with full user and system code analysis reveals the significant effect of system accesses, and this effect increases with multicomputer size. The time distribution of an application's message-passing operations is found to more strongly affect cache performance than the total amount of time spent in message-passing code     

多服务交换资源虚拟分割算法的研究

为用户或应用提供多样性服务是网络发展的趋势，不同的服务需要相应的网络转发或交换机制支持，实现多服务交换或转发的关键是资源分配和管理，该文提出一种支持面向应用的多服务交换路由器的资源虚拟分割算法，它结合可编程路由器，根据不同应用的转发需求，为不同转发服务分配一定范围的虚拟资源区间，该虚拟分割区间能够隔离和保护不同应用网络流，为其提供一定的服务质量保障，并使服务间能够可控，动态地共享多余的资源。     

Rapid digital system prototyping: current practice, futurechallenges

A top-down methodology that emphasizes modular, upgradable designs solves some problems with the current design process for application-specific signal processors. Virtual prototyping, model year architectures, and reuse-based design form the pillars of this new approach, which promises to raise industrial design productivity and competitiveness     

Contemporary application-domain taxonomies

In recent years it has become clear that application-independent techniques and tools must be supplemented with an application-specific approach. We begin to identify the foundations needed for application-specific software research by examining the role and nature of current application taxonomies     

SOS: Synthesis of application-specific heterogeneous multiprocessor systems

This paper describes a formal synthesis approach to design of optimal application-specific heterogeneous multiprocessor systems. The method generates a static task execution schedule along with the structure of the multiprocessor system and a mapping of subtasks to processors. The approach itself is quite general, but its application is demonstrated with a specific style of design. The approach involves creation of a Mixed Integer-Linear Programming (MILP) model and solution of the model. A primary component of the model is the set of relations that must be satisfied to ensure proper ordering of various events in the task execution as well as to ensure completeness and correctness of the system. Several experiments and tradeoff studies have been performed using the approach. These results indicate that the approach can be a useful tool in designing application-specific multiprocessor systems.     

基于Cramer’s V的连续属性离散化算法

在类-属性相关离散化方法的基础上,提出一种基于Cramer’s V的连续属性离散化算法CVM,该方法利用统计学中的Cramer’s V来量化类-属性相关度,以保证离散后的类-属性相关度最大。与CADD和CAIM算法的实验比较以及对离散化后的数据进行C4.5分类测试,表明CVM算法性能良好,其离散化的数据明显地提高了分类器的预测精度。     

面向应用的NoC带宽感知路由技术

片上互连网络是片上通信问题的有效解决方案,但存在严重的资源限制。标准拓扑结构难以满足应用的流量需求,同时还导致大量功耗和面积的开销。适用于通用系统的NoC设计难以满足面向服务质量可预测的互连。给出一种面向应用的带宽感知路由技术,针对具体的应用,首先使用基于遗传算法的映射技术获得IP核到网络节点的最佳映射,然后通过带宽感知的路由算法为网络中的每条数据传输生成最短路由,并通过虚信道静态分配保证该路由是无死锁的。为了减少路由表的硬件开销,还结合使用了路由表压缩的方法。仿真结果表明,所提出的路由技术与现有的路由算法相比,具有更好的时延性能。