Trust-based access control for collaborative systems

In distributed, heterogeneous and network-connected collaborative environments where resources are provided to diverse unknown users for their applications, it is necessary to define access control for resources. Access control for such systems is defined as the ability to authorise or repudiate access to resources by a particular user. Traditional access control solutions are inherently inadequate for collaborative systems because they are effective only in situations where the system knows in advance which users are going to access the resources and what are their access rights so that they can be predefined by the developers or security administrators, but in collaborative systems the number of users as well as their usage on resources is not static. Targeting collaborative systems, a fine grained, flexible, persistent trust-based model for protecting the access and usage of digital resources is defined in this paper using radial basis function neural network (RBFNN). RBFNN classifies the users requesting the resources as trustworthy and non-trustworthy based on their attributes. RBFNN is used for classification because of its ability to generalise well for even unseen data and non-iterative method employed in its training. A proof of concept implementation backed by extensive set of tests on the real data collected for one such collaborative systems, i.e. Enabling Grids for E-Science grid demonstrated that the design is sound for collaborative systems where access of resources are provided to large and unknown users with their variant set of requirements.     

Accountability for Perfection

Accountability could play a much bigger role in getting software producers to implement systems that are more secure and as an alternative to prevention for defending against attacks. Accountability, however, requires attribution of action. Current system development processes are weak here, as are our system designs. In both settings, forensics is key for supporting accountability.     

Cooperative power-aware scheduling in grid computing environments

Energy usage and its associated costs have taken on a new level of significance in recent years. Globally, energy costs that include the cooling of server rooms are now comparable to hardware costs, and these costs are on the increase with the rising cost of energy. As a result, there are efforts worldwide to design more efficient scheduling algorithms. Such scheduling algorithm for grids is further complicated by the fact that the different sites in a grid system are likely to have different ownerships. As such, it is not enough to simply minimize the total energy usage in the grid; instead one needs to simultaneously minimize energy usage between all the different providers in the grid. Apart from the multitude of ownerships of the different sites, a grid differs from traditional high performance computing systems in the heterogeneity of the computing nodes as well as the communication links that connect the different nodes together. In this paper, we propose a cooperative, power-aware game theoretic solution to the job scheduling problem in grids. We discuss our cooperative game model and present the structure of the Nash Bargaining Solution. Our proposed scheduling scheme maintains a specified Quality of Service (QoS) level and minimizes energy usage between all the providers simultaneously; energy usage is kept at a level that is sufficient to maintain the desired QoS level. Further, the proposed algorithm is fair to all users, and has robust performance against inaccuracies in performance prediction information.     

PGSW-OS: a novel approach for resource management in a semantic web operating system based on a P2P grid architecture

A web operating system is an operating system that users can access from any hardware at any location. A peer-to-peer (P2P) grid uses P2P communication for resource management and communication between nodes in a grid and manages resources locally in each cluster, and this provides a proper architecture for a web operating system. Use of semantic technology in web operating systems is an emerging field that improves the management and discovery of resources and services. In this paper, we propose PGSW-OS (P2P grid semantic Web OS), a model based on a P2P grid architecture and semantic technology to improve resource management in a web operating system through resource discovery with the aid of semantic features. Our approach integrates distributed hash tables (DHTs) and semantic overlay networks to enable semantic-based resource management by advertising resources in the DHT based upon their annotations to enable semantic-based resource matchmaking. Our model includes ontologies and virtual organizations. Our technique decreases the computational complexity of searching in a web operating system environment. We perform a simulation study using the Gridsim simulator, and our experiments show that our model provides enhanced utilization of resources, better search expressiveness, scalability, and precision.     

基于层次结构的网格资源管理系统

首先介绍当前的资源管理系统模型 ;然后根据网格资源的特点提出了具有层次结构的网格资源管理系统模型 ,对开发这种系统的关键技术作了探讨 ,其中包括资源管理流程、资源需求、资源提供、资源分配等几方面 ,并已在研制的网格资源管理系统JobCenter Grid中加以实现。     

合同计算操作系统的设计问题

合同计算技术是一种崭新的计算资源管理策略，在该策略中，使用计算资源的实体需要获取计算资源的使用情况，但在一般系统中却没有这方面的信息，在本文里，我们介绍了如何使得计算资源可被预先估计的系统设计问题。     

Data discovery algorithm for scientific data grid environment

In modern scientific computing communities, scientists are involved in managing massive amounts of very large data collections in a geographically distributed environment. Research in the area of grid computing has given us various ideas and solutions to address these requirements. Data grid mostly deals with large computational problems and provides geographically distributed resources for large-scale data-intensive applications that generate large data sets. Peer-to-peer (P2P) networks have also become a major research topic over the last few years. In a distributed P2P system, a discovery algorithm is required to locate specific information, applications, or users within the system. In this research work, we present our scientific data grid as a large P2P-based distributed system model. By using this model, we study various discovery algorithms for locating data sets in a data grid system. The algorithms we studied are based on the P2P architecture. We investigate these algorithms using our Grid Simulator developed using PARSEC. In this paper, we illustrate our scientific data grid model and our Grid Simulator. We then analyze the performance of the discovery algorithms relative to their average number of hop, success rates and bandwidth consumption.     

Integrate software agents and CORBA in computational grid

This paper presents an Agent-based Computational Grid (ACG), which applies the concept of CORBA and agent to computational grid. The ACG system is used to implement a uniform higher level management of the computing resources and services on the Grid, and provide users with a consistent and transparent interface for accessing such services. In ACG grid, grid services are implemented by CORBA or by grid agent. Grid agents and CORBA objects will interact with each other to achieve user's service request. Our solution is the creation of a bridge between the CORBA and grid agents. The solution provides with the opportunity of considering an agent as a CORBA service and accessing CORBA services even from a grid agent. Thus, in AGC grid, existing legacy systems can be easily exploited as grid services. In this paper, firstly, the features of ACG grid are described, and then the design and implementation are given. Finally, some conclusions are given.     

基于模糊多目标决策的网格资源调度算法研究

针对如何提高网格资源的使用效率和用户满意度及系统效率等问题,提出了一个基于层次调度模型的、将资源的表示与需求用XML方式描述、以模糊多目标决策理论为资源调度策略,以用户满意度和系统资源利用率为主要目标的综合网格资源调度算法.该算法不仅最大程度提高用户的满意度,而且较好地解决了网格资源的均衡使用,极大地提高了系统效率,对网格系统综合性能有明显地提高.     

Performance modeling of parallel applications for grid scheduling

Grids consist of both dedicated and non-dedicated clusters. For effective mapping of parallel applications on grid resources, a grid metascheduler has to evaluate different sets of resources in terms of predicted execution times for the applications when executed on the sets of resources. In this work, we have developed a comprehensive set of performance modeling strategies for predicting execution times of parallel applications on both dedicated and non-dedicated environments. Our strategies adapt to changing network and CPU loads on the grid resources. We have evaluated our strategies on 8, 16, 24 and 32-node clusters with random loads and load traces from a grid system. Our strategies give less than 30% average percentage prediction errors in all cases, which, to our knowledge, is the best reported for non-dedicated environments. We also found that grid scheduling using predictions of execution times from our performance modeling techniques will lead to perfect mapping of applications to resources in many cases.     

基于OGSA的网格计费系统

介绍了基于开放网格服务体系结构(OGSA)的山东大学网格计费系统－—SDUGAS，该系统主要致力于解决网格环境下异构资源使用的记账和计费问题，为用户和管理员提供良好的网格服务，在此基础上大力提高网格资源的利用率。山东大学网格计费系统的设计和实现以OGSA为标准，充分考虑了网格环境下系统的可扩展性和可移植性，强调在网格环境下数据描述的一致性和系统集成安装的易操作性。介绍了SDUGAS的体系结构、实现的基本原理和方法、资源信息的采集过程、资源预订、资源的价格策略以及网格银行的设计与实现等内容，给出了一个SDUGAS记账和计费过程的简单实例。     

基于网格环境的资源管理模型研究

针对目前网格环境下资源管理存在的问题和现状，提出了一种基于市场机制的资源管理模型。该模型以一般均衡理论为基础，计算出资源的市场价格，依靠市场机制，实现计算网格资源的优化分配。     

Software framework concept with visual programming and digital twin for intuitive process creation with multiple robotic systems

With the progressive digitalization in industrial manufacturing, the usage of complex robotic systems in both intralogistics and production is expected to increase. This proposes a challenge for planners and shop floor workers, as programming and interacting with these various systems leads to a high cognitive load. Especially the broad range of different manufacturer specific software leads to a number of problems, e.g. the program-synchronization between different systems and the often necessary workshops for workers. These problems can lead to inefficient programming and planning operations, bad worker satisfaction and human errors. In this paper, we present a modular, system agnostic and human centered software framework that unifies the programming of different systems, to enable centralized and intuitive system programming for non-expert operators. Our software framework utilizes visual programming concepts together with an integrated digital twin of the factory and a novel graph-based programming interface. We explain our concept in detail and describe our validation through integration into a realistic industrial setup with three different systems. In addition, we provide an evaluation of our concept's usability with an experimental user study and discuss the results of the study and the software implementation. Our study results show that even non-technical users are able to use our software after a brief introduction to create complex processes that involve multiple machines working in parallel. All users reported high usability and expert users reported that the visual process editor has enough features to create processes for industrial applications. Finally, we conclude this paper by providing an outlook on future work and use-cases of our software.     

基于Web Service与LDAP的网格信息服务的设计

网格作为一种广域的大规模分布式环境，其中包含大量类型复杂、地理分布且动态变化的资源，在这样的环境中如何提供一种管理机制，为用户提供注册、发现资源及反映资源状态等方面的信息服务，最终以单一映像的形式展现在用户面前是非常必要的。为此该文设计了一种网格环境中信息服务系统的设计模型及基于Web Service和轻量目录访问协议(LDAP)的具体实现。     

The organic grid: self-organizing computation on a peer-to-peer network

Desktop grids have been used to perform some of the largest computations in the world and have the potential to grow by several more orders of magnitude. However, current approaches to utilizing desktop resources require either centralized servers or extensive knowledge of the underlying system, limiting their scalability. We propose a new design for desktop grids that relies on a self-organizing, fully decentralized approach to the organization of the computation. Our approach, called the organic grid, is a radical departure from current approaches and is modeled after the way complex biological systems organize themselves. Similar to current desktop grids, a large computational task is broken down into sufficiently small subtasks. Each subtask is encapsulated into a mobile agent, which is then released on the grid and discovers computational resources using autonomous behavior. In the process of "colonization" of available resources, the judicious design of the agent behavior produces the emergence of crucial properties of the computation that can be tailored to specific classes of applications. We demonstrate this concept with a reduced-scale proof-of-concept implementation that executes a data-intensive independent-task application on a set of heterogeneous, geographically distributed machines. We present a detailed exploration of the design space of our system and a performance evaluation of our implementation using metrics appropriate for assessing self-organizing desktop grids.     

Web platforms for scientific research

This paper considers current trends in creating systems for convenient and secure remote submission (by authorized users) of jobs to computing resources of different types, including supercomputers, clusters, cloud resources, storages, databases, and grid infrastructures. Presently, large computing and storage resources are capable of solving, on their own, the majority of practical problems in the field of science and technology. Therefore, the focus in developing next-generation middleware shifts from global grid systems towards creating convenient and efficient means of access to large individual resources. A web platform for remote access to computing resources is a set of special web services and application-oriented web interfaces. Such web platforms, on a centralized basis, provide users with a number of services interrelated by a specific application area, principle of access, and interface. In this paper, general principles of creating such platforms are considered and some particular implementations of web platforms are briefly described.     

A Resource Selection System for Cycle Stealing in GPU Grids

This paper presents a resource selection system for exploiting graphics processing units (GPUs) as general-purpose computational resources in desktop Grid environments. Our system allows Grid users to share remote GPUs, which are traditionally dedicated to local users who directly see the display output. The key contribution of the paper is to develop this novel system for non-dedicated environments. We first show criteria for defining idle GPUs from the Grid users’ point of view. Based on these criteria, our system uses a screensaver approach with some sensors that detect idle resources at a low overhead. The idea for this lower overhead is to avoid GPU intervention during resource monitoring. Detected idle GPUs are then selected according to a matchmaking service, making the system adaptive to the rapid advance of GPU architecture. Though the system itself is not yet interoperable with current desktop Grid systems, our idea can be applied to screensaver-based systems such as BOINC. We evaluate the system using Windows PCs with three generations of nVIDIA GPUs. The experimental results show that our system achieves a low overhead of at most 267 ms, minimizing interference to local users while maximizing the performance delivered to Grid users. Some case studies are also performed in an office environment to demonstrate the effectiveness of the system in terms of the amount of detected idle time.     

Deploying Web-based visual exploration tools on the grid

Grid-based computing facilitates access to different resources. But management in a grid-based environment isn't centralized. To use grid resources effectively, researchers need a central access point to manage the resources, provide a visual means to explore the data, and record these explorations for further investigation and dissemination. This article describes such a system that's being developed jointly by the University of California, Davis, and the Lawrence Berkeley National Laboratory (LBNL). The centralized system acts as a portal into grid-enabled visualization systems. Scientists using the portal can focus on the important task of extracting insights from their data through visualization instead of having to worry about process management. Because scientists at LBNL and their collaborators require access to the portal from around the world, the portal's interface is entirely Web-based. Authenticated users only need a standards-compliant Web browser to explore their data from anywhere in the world. The portal provides a Web-based interface not just for exploring but also for encapsulating visualization data. Encapsulating the process lets users reproduce the visualization results for validation or extend those results by continuing data exploration. We discuss the integration of our grid-enabled visualization server, the visualization Web application that performs the visualization session management, and the Web-based interface.     

A service accountability framework for QoS service management and engineering

Service science, management and engineering (SSME) research is to study the methodology and technology for service innovation, design, development and delivery. Since service industry is very quality-sensitive and trust-dependent, we propose a service accountability management framework to detect, diagnose, defuse and disclose the root cause for any problematic service process. The accountability support is important for SSME since service processes often rely on external service providers to deliver part of the service functionalities. A service system must have effective yet efficient mechanisms to ensure that every external service is delivering a consistent and acceptable level of performance to meet the end-to-end quality of service (QoS) of the whole service process. In this paper, we present the accountability framework, identify the components in an accountable service architecture, and design an accountability diagnosis methodology. We also briefly present the inteLLigent Accountability Management Architecture (LLAMA) project which implements the accountability service bus (ASB), an agent-based middleware to support the monitoring, diagnosis, and reconfiguration of e-services. LLAMA ASB interacts with accountability agents to monitor services and the Accountability Authority to automatically diagnose faulty situations. The LLAMA technology is useful to ensure the QoS in SSME-based systems.     

Analyzing the feasibility of building a new mass storage system on distributed resources

The average PC now contains a large and increasing amount of storage with an ever greater amount left unused. We believe there is an opportunity for organizations to harness the vast unused storage capacity on their PCs to create a very large, low‐cost, shared storage system. What is needed is the proper storage system architecture and software to exploit and manage the unused portions of existing PC storage devices across an organization and make it reliably accessible to users and applications. We call our vision of such a storage system Storage@desk (SD). This paper describes our first step towards the realization of SD—a study of machine and storage characteristics and usage in a model organization. We studied 729 PCs in an academic institution for 91 days, monitoring the configuration, load and usage of the major machine subsystems, i.e. disk, memory, CPU and network. To further analyze the availability characteristics of storage in an SD system, we performed a trace‐driven simulation of some basic storage allocation strategies. This paper presents the results of our data collection efforts, our analysis of the data, our simulation results and our conclusion that an SD system is indeed feasible and holds promise as a cost‐effective way to create massive storage systems. Copyright © 2007 John Wiley & Sons, Ltd.