Load‐balanced and locality‐aware scheduling for data‐intensive workloads at extreme scales

Data‐driven programming models such as many‐task computing (MTC) have been prevalent for running data‐intensive scientific applications. MTC applies over‐decomposition to enable distributed scheduling. To achieve extreme scalability, MTC proposes a fully distributed task scheduling architecture that employs as many schedulers as the compute nodes to make scheduling decisions. Achieving distributed load balancing and best exploiting data locality are two important goals for the best performance of distributed scheduling of data‐intensive applications. Our previous research proposed a data‐aware work‐stealing technique to optimize both load balancing and data locality by using both dedicated and shared task ready queues in each scheduler. Tasks were organized in queues based on the input data size and location. Distributed key‐value store was applied to manage task metadata. We implemented the technique in MATRIX, a distributed MTC task execution framework. In this work, we devise an analytical suboptimal upper bound of the proposed technique, compare MATRIX with other scheduling systems, and explore the scalability of the technique at extreme scales. Results show that the technique is not only scalable but can achieve performance within 15% of the suboptimal solution. Copyright © 2015 John Wiley & Sons, Ltd.     

基于认知模型的室内移动服务机器人人机耦合协同作业机制

针对老年人和残疾人这类特殊用户群体与服务机器人构成的人机智能系统,提出了基于ACT-R(理性思维的适应性控制)认知架构模型的室内移动服务机器人人机耦合协同作业机制.基于ACT-R认知架构对人机一体化室内移动服务机器人人机协同作业系统进行了总体设计,利用简单自然的人机效应通道,设计了基于ACT-R认知架构的人机耦合界面;通过人-机-环境空间感知耦合,提出并建立了室内移动服务机器人人机一体化协同决策作业机制.最后在室内环境下进行移动服务机器人人机协同作业实验,系统安全高效地完成了作业任务,验证了该机制的有效性.     

A component‐based framework for radio‐astronomical imaging software systems

This paper describes a component‐based framework for radio‐astronomical imaging software systems. We consider optimal re‐use strategies for packages of disparate architectures brought together within a modern component framework. In this practical case study, the legacy codes include both procedural and object‐oriented architectures. We consider also the special requirements on scientific component middleware, with a specific focus on high‐performance computing. We present an example application in this component architecture and outline future development planned for this project. Copyright © 2007 John Wiley & Sons, Ltd.     

An integration experience of a software architecture and a monitoring infrastructure to deploy applications with non‐functional requirements in computing grids

Resource management is an important aspect to consider regarding applications that might have different non‐functional or operational requirements, when running in distributed and heterogeneous environments. In this context, it is necessary to provide the means to specify the required resource constraints and an infrastructure that can adapt the applications in light of the changes in resource availability. We adopted a contract‐based approach to describe and maintain parallel applications that have non‐functional requirements in a Computing Grid context, called ZeliGrid. To form the supporting infrastructure we have designed a software architecture that integrates some of the Globus services, the LDAP and the NWS monitoring services. Some modules that map the contract approach into software artifacts were also integrated to this architecture. This paper addresses the architecture and integration issues of our approach, as well as how we put the pieces together highlighting deployment and implementation details, which have to consider diverse aspects such as monitoring, security and dynamic reconfiguration. Copyright © 2010 John Wiley & Sons, Ltd.     

A standards‐based Grid resource brokering service supporting advance reservations,coallocation, and cross‐Grid interoperability

The problem of Grid‐middleware interoperability is addressed by the design and analysis of a feature‐rich, standards‐based framework for all‐to‐all cross‐middleware job submission. The architecture is designed with focus on generality and flexibility and builds on extensive use, internally and externally, of (proposed) Web and Grid services standards such as WSRF, JSDL, GLUE, and WS‐Agreement. The external use provides the foundation for easy integration into specific middlewares, which is performed by the design of a small set of plugins for each middleware. Currently, plugins are provided for integration into Globus Toolkit 4 and NorduGrid/ARC. The internal use of standard formats facilitates customization of the job submission service by replacement of custom components for performing specific well‐defined tasks. Most importantly, this enables the easy replacement of resource selection algorithms by algorithms that address the specific needs of a particular Grid environment and job submission scenario. By default, the service implements a decentralized brokering policy, striving to optimize the performance for the individual user by minimizing the response time for each job submitted. The algorithms in our implementation perform resource selection based on performance predictions, and provide support for advance reservations as well as coallocation of multiple resources for coordinated use. The performance of the system is analyzed with focus on overall service throughput (up to over 250 jobs per min) and individual job submission response time (down to under 1 s). Copyright © 2009 John Wiley & Sons, Ltd.     

Architecting and implementing distributed Web applications using the graph‐oriented approach

This paper presents a graph‐oriented framework, called WebGOP, for architecture modeling and programming of Web‐based distributed applications. WebGOP is based on the graph‐oriented programming (GOP) model, under which the components of a distributed program are configured as a logical graph and implemented using a set of operations defined over the graph. WebGOP reshapes GOP with a reflective object‐oriented design, which provides powerful architectural support in the World Wide Web environment. In WebGOP, the architecture graph is reified as an explicit object which itself is distributed over the network, providing a graph‐oriented context for the execution of distributed applications. The programmer can specialize the type of graph to represent a particular architecture style tailored for an application. WebGOP also has built‐in support for flexible and dynamic architectures, including both planned and unplanned dynamic reconfiguration of distributed applications. We describe the WebGOP framework, a prototypical implementation of the framework on top of SOAP, and a performance evaluation of the prototype. The prototype demonstrated the feasibility of our approach. Results of the performance evaluation showed that the overhead introduced by WebGOP over SOAP is reasonable and acceptable. Copyright © 2003 John Wiley & Sons, Ltd.     

A negotiation‐based service selection approach using swarm intelligence and kernel density estimation

Nowadays, the cloud computing environment is becoming a natural choice to deploy and provide Web services that meet user needs. However, many services provide the same functionality and high quality of service (QoS) but different self‐adaptive behaviors. In this case, providers' adaptation policies are useful to select services with high QoS and high quality of adaptation (QoA). Existing approaches do not take into account providers' adaptation policies in order to select services with high reputation and high reaction to changes, which is important for the composition of self‐adaptive Web services. In order to actively participate to compositions, candidate services must negotiate their self‐* capabilities. Moreover, they must evaluate the participation constraints against their capabilities specified in terms of QoS and adaptation policies. This paper exploits a variant of particle swarm optimization and kernel density estimation in the selection of service compositions and the concurrent negotiations of their QoS and QoA capabilities. Selection and negotiation processes are held between intelligent agents, which adopt swarm intelligence techniques for achieving optimal selection and optimal agreement on providers' offers. To resolve unknown autonomic behavior of candidate services, we deal with the lack of such information by predicting the real QoA capabilities of a service through the kernel density estimation technique. Experiments show that our solution is efficient in comparison with several state‐of‐the‐art selection approaches.     

A service‐based runtime environment for native applications

Unlike interpreted application programs that run within the rich runtime environment of their own interpreters, natively compiled application programs are typically thought of as executing on the barebones runtime environment provided by their own operating systems and dynamic linkers. This article presents the notion of a service‐based runtime (SBRT) environment for natively compiled application programs, in which the current dynamic linker is only a core service and other extensive middleware‐type services are available to the running application program. It then describes a dynamic‐linker‐based implementation of such an environment, called dlSBRT. dlSBRT implements a unified interface that allows it to be extensible by means of extension dynamic services. Implemented examples of such services are presented and the performance of dlSBRT, when such example services are deployed, is evaluated. Copyright © 2009 John Wiley & Sons, Ltd.     

A transformation‐based approach to testing concurrent programs using UML activity diagrams

Unified Modeling Language (UML) activity diagrams are widely used to model concurrent interaction among multiple objects. In this paper, we propose a transformation‐based approach to generating scenario‐oriented test cases for applications modeled by UML activity diagrams. Using a set of transformation rules, the proposed approach first transforms a UML activity diagram specification into an intermediate representation, from which it then constructs test scenarios with respect to the given concurrency coverage criteria. The approach then finally derives a set of test cases for the constructed test scenarios. The approach resolves the difficulties associated with fork and join concurrency in the UML activity diagram and enables control over the number of the resulting test cases. We further implemented a tool to automate the proposed approach and studied its feasibility and effectiveness using a case study. Experimental results show that the approach can generate test cases on demand to satisfy a given concurrency coverage criterion and can detect up to 76.5% of seeded faults when a weak coverage criterion is used. With the approach, testers can not only schedule the software test process earlier, but can also better allocate the testing resources for testing concurrent applications. Copyright © 2015 John Wiley & Sons, Ltd.     

Feature‐based approach to object‐oriented engineering of applications for reuse

Object‐oriented technology is gaining popularity among software engineers with the goal of building reusable and adaptable software. Unfortunately, however, most methods introduced so far are not domain‐oriented and do not address the issue of reuse directly. For these methods, software reuse is not the primary goal; it is only a by‐product. The feature‐oriented reuse method, FORM, is extended in this paper for improving the object‐oriented engineering of applications for reuse. FORM concentrates on analyzing and modeling commonalities and differences in the applications of a given domain in terms of capability, operating environment, domain technology, and implementation technique features. These features are used to systematically derive objects that are tied to the features, and to develop reusable and adaptable domain architectures. We found that FORM facilitates analysis of variability (and commonality) of software before engineering and implementation start, and with this understanding, adaptability and reusability can be built into software. Feature modeling has been found to be an effective method for identifying and modeling reusable objects. Copyright © 2000 John Wiley & Sons, Ltd.     

A distributed and multi‐tiered software architecture for assessing e‐Commerce recommendations

Recently, an ever increasing number of e‐Commerce tools has been made available that are able to help customers by generating purposed recommendations. Many of them are centralized so that they have to face problems related to efficiency and scalability. A few of them are distributed, but in this case, the complexity of the e‐Commerce process implies computation overhead on the client side, which is often unsuitable if mobile devices are used by customers. In this paper, we study how the software distribution in recommender systems affects their performances, depending on the characteristics of the e‐Commerce population. To this end, we present a distributed testbed architecture for e‐Commerce recommender systems using a multi‐tiered agent‐based approach to generate effective recommendations without requiring such an onerous amount of computation per single client. We use such a testbed to study the main advantages and limitations associated with the problem of distributing the computation of recommendations. Copyright © 2016 John Wiley & Sons, Ltd.     

A specification language and service‐oriented architecture to support distributed data management

In some research analysis organizations, effort is duplicated when disseminating raw information to multiple research groups. Although the various groups work on different problems, many times, the initial raw information used is the same. A solution to this problem is creating a centralized process for storing and disseminating common information using database technologies. In this paper, the requirements that must be met to create this distributed database management architecture are described. To support these requirements, a specification language, Specialized Format Markup Language (SFML), and supporting service‐oriented architecture, Specialized Format Generation (SFG), are introduced. These implementations and technologies support the translation of data from relational database formats into user‐specified legacy formats. In addition, this implementation supports the presentation of the resulting data across a Web‐based, distributed medium. SFML and SFG incorporate current technologies such as the eXtensible Markup Language (XML), Java Servlets, the eXtensible Stylesheet Language (XSL), and other relational database approaches. Copyright © 2004 John Wiley & Sons, Ltd.     

A multi‐layered architecture for managing graphical interfaces and tutoring mixed‐strategy dialogues

This paper describes a tool set that allows a courseware author to design a student interface. These tools produce systems dedicated to intelligent computer aided learning, with a better balance between planned tutoring and free‐exploration of micro‐worlds. Mixing these two approaches leads to a distinction between the pedagogical objectives and the presentation elements. Reactive graphical interfaces are better suited to develop micro‐worlds, while the tutoring relies on pedagogical strategies. Then, a multi‐layered architecture is designed in order to use such a graphical student interface under the control of teaching strategies and intentional dialogues. Tutoring rules drive these dialogues by combining several types of functions: predefined strategies, interaction management primitives and pedagogical tactics. These functions are means to articulate the reactive and graphical level with the logical and intentional one. Copyright © 1999 John Wiley & Sons, Ltd.     

Stochastic modelling and simulation approaches to analysing enhanced fault tolerance on service‐based software systems

Presently, service‐based software systems (SBSSs) have been heavily deployed to fulfil the functionalities of cloud computing and are widely used in many other application fields. Additionally, maintaining functionality and quality of service levels becomes increasingly important for SBSSs; this is because system operational failures may cause great financial loss to an organization. Fault tolerance (FT) is usually used to provide continuous and reliable system service delivery when failures occur. However, the reliability and performance of FT should be carefully analysed because of the overhead of invoking redundant services. It is also noted that the single point of failure on the FT adjudicators as well as the failure correlation also hamper the benefits of FT in SBSSs. To address these problems, this paper proposes two approaches, the stochastic modelling approach and the simulation approach, for analysing the reliability and performance of generalized FT designs. The first approach is suitable for quick analysis at an early design stage, while the second approach is built on top of the ns‐3 simulator and could be well adapted to incorporate varied uncertainty models in the SBSS environments Extensive experiments and analyses uncover some characteristics that could be useful for SBSS engineers. Copyright © 2015 John Wiley & Sons, Ltd.