Deployment of a cloud pipeline for real-time visual inspection using fast streaming high-definition images

We investigate the challenges of building an end-to-end cloud pipeline for real-time intelligent visual inspection system for use in automotive manufacturing. Current methods of visual detection in automotive assembly are highly labor intensive, and thus prone to errors. An automated process is sought that can operate within the real-time constraints of the assembly line and can reduce errors. Components of the cloud pipeline include capture of a large set of high-definition images from a camera setup at the assembly location, transfer and storage of the images as needed, execution of object detection, and notification to a human operator when a fault is detected. The end-to-end execution must complete within a fixed time frame before the next car arrives in the assembly line. In this article, we report the design, development, and experimental evaluation of the tradeoffs of performance, accuracy, and scalability for a cloud system.     

Maintenance of sustainable operation of pipeline-parallel computing systems in the cloud environment

This paper reviews the model and algorithm for the intelligent scheduling of a pipelineparallel computing process, which takes into account changes in the resource consumption of computing nodes. The solution is implemented in a virtual cloud environment, which provides security and accessibility of high-performance computing services due to the isolation of physical resources and the monitoring and optimization of their use, as well as the adaptive distribution of computational load.     

云环境下周期和非周期混合实时任务双容错调度算法

云环境中的处理机故障已成为云计算不可忽视的问题,容错成为设计和发展云计算系统的关键需求。针对一些容错调度算法在任务调度过程中调度效率低下以及任务类型单一的问题,提出一种处理机和任务主副版本分组的容错调度方法;并给出了副版本可重叠执行的判定方法,以及任务最坏响应时间的计算公式。通过实验和分析表明,和以前算法相比,将处理机分成两组分别执行任务主版本和任务副版本,减少了任务调度所需进行可调度测试的时间,增加了副版本重叠执行的机会,减少了所需的处理机个数,对提高系统处理机的利用率和容错调度的效率具有重要的意义。     

A real-time responsiveness measurement method of linux-based mobile systems for P2P cloud systems

Linux-based mobile computing systems such as robots, electronic control devices, and smart-phone are the most important types of P2P cloud systems in recent days. To improve the overall performance of networked systems, each mobile computing system requires real-time characteristics. For this reason, mobile computing system developers want to know how well real-time responsiveness is supported; several real-time measurement tools have been proposed. However, those previous tools have their own measurement schemes and we think that the results from those models do not show how responsive those systems are. In this paper, we propose ELRM, a new real-time measurement method that has clear measurement interval definitions and an accurate measurement method for real-time responsiveness. We evaluate ELRM on various mobile computing systems and compare it with other existing models. As a result, our method can obtain more accurate and intuitive real-time responsiveness measurement results.     

A programming environment for real-time control of distributed multiple robotic systems

In recent years there has been great interest in robot software control architectures. However, although many interesting solutions have been presented, most of the research problems tackled related to a single robot perception, navigation and action in everyday environments. Instead, most of the practical applications of mobile robotics for service tasks in civilian environments consist of systems composed of multiple robots communicating with each other, with external sensing and actuating devices, and with external supervising workstations. RoboCup offers a great opportunity to deal with this problem. In fact the software architecture of a robot soccer player must allow successful intra-robot integration of the different activities (visual perception, path planning, strategy planning, motion control, etc.) spanning many different types of representation (raw sensor data, images, symbolic plans, etc.) and it must also guarantee successful inter-robot integration by supporting communication and cooperation. This paper focuses on this problem, presenting ETHNOS-IV - a programming environment for the design of a real-time control system composed of different robots, devices and external supervising or control stations - which has been successfully used within the Italian ART robot team in the RoboCup-99 competition. ETHNOS provides support from three main point of views which will be addressed in detail: inter-robot and intra-robot communication, realtime task scheduling, and software engineering and code reuse. Experimental results illustrating the advantages of this approach will also be presented.     

The design and analysis of real-time systems using the ASTRAL software development environment

ASTRAL is a formal specification language for real-time systems. It is intended to support formal software development and, therefore, has been formally defined. The structuring mechanisms in ASTRAL allow one to build modularized specifications of complex systems with layering. A real-time system is modeled by a collection of state machine specifications and a single global specification. This paper discusses the ASTRAL Software Development Environment (SDE), which is an integrated set of design and analysis tools based on the ASTRAL formal framework. The tools that make up the support environment are a syntax-directed editor, a specification processor, a verification condition generator, a browser kit, a model checker, and a mechanical theorem prover. This revised version was published online in June 2006 with corrections to the Cover Date.     

An environment for integrated development and evaluation of real-time distributed database systems

Real-time database systems must maintain consistency while minimizing the number of transactions that miss the deadline. To satisfy both the consistency and real-time constraints, there is the need to integrate synchronization protocols with real-time priority scheduling protocols. One of the reasons for the difficulty in developing and evaluating database synchronization techniques is that it takes a long time to develop a system, and evaluation is complicated because it involves a large number of system parameters that may change dynamically. This paper describes an environment for investigating distributed real-time database systems. The environment is based on a concurrent programming kernel that supports the creation, blocking, and termination of processes, as well as scheduling and interprocess communication. The contribution of the paper is the introduction of a new approach to system development that utilizes a module library of reusable components to satisfy three major goals: modularity, flexibility, and extensibility. In addition, experiments for real-time concurrency control techniques are presented to illustrate the effectiveness of the environment.This work was supported in part by ONR contract # NOOO14-88-K-0245, by DOE contract # DEFG05-88-ER25063, by CIT contract # CIT-INF-90-011, and by IBM Federal Systems Division.     

Challenges in real-time virtualization and predictable cloud computing

Cloud computing and virtualization technology have revolutionized general-purpose computing applications in the past decade. The cloud paradigm offers advantages through reduction of operation costs, server consolidation, flexible system configuration and elastic resource provisioning. However, despite the success of cloud computing for general-purpose computing, existing cloud computing and virtualization technology face tremendous challenges in supporting emerging soft real-time applications such as online video streaming, cloud-based gaming, and telecommunication management. These applications demand real-time performance in open, shared and virtualized computing environments. This paper identifies the technical challenges in supporting real-time applications in the cloud, surveys recent advancement in real-time virtualization and cloud computing technology, and offers research directions to enable cloud-based real-time applications in the future.     

A flexible environment for rapid prototyping and analysis of distributed real-time safety-critical systems

Currently, there is a plethora of low-cost commercial off-the-shelf (COTS) hardware available for implementing control systems. These range from devices with fairly low intelligence, e.g. smart sensors and actuators, to dedicated controllers such as PowerPC, programmable logic controllers (PLCs) and PC-based boards to dedicated systems-on-a-chip (SoC) ASICS and FPGAs. When considering the construction of complex distributed systems, e.g. for a ship, aircraft, car, train, process plant, the ability to rapidly integrate a variety of devices from different manufacturers is essential. A problem, however, is that manufacturers prefer to supply proprietary tools for programming their products. As a consequence of this lack of ‘openness’, rapid prototyping and development of distributed systems is extremely difficult and costly for a systems integrator. Great opportunities thus exist to produce high-performance, dependable distributed systems. However, the key element that is missing is software tool support for systems integration. The objective of the Flexible Control Systems Development and Integration Environment for Control Systems (FLEXICON) project IST-2001-37269 is to solve these problems for industry and reduce development and implementation costs for distributed control systems by providing an integrated suite of tools to support all the development life-cycle of the system. Work within the Rolls-Royce supported University Technology Centre (UTC) is investigating rapid prototyping of controllers for aero-engines, unmanned aerial vehicles and ships. This paper describes the use of the developed co-simulation environment for a high-speed merchant vessel propulsion system application.     

实时嵌入式异构环境下多优先级混合任务调度动态策略

针对现有异构环境下的调度策略,引入迫切密度和剩余价值密度,分析迫切密度和剩余价值密度调节任务执行紧急程度的影响、对优先级制定,通过构建单有向无环图（ DAG）系统模型实现了混合任务的动态调度。仿真实验结果表明：该调度策略在系统负载较高的情况下,仍有较优的任务执行效能和避免颠簸现象。     

云计算环境下的软件测试研究

本文主要介绍了云计算环境下的软件测试相关内容,总结了云测试相对于传统测试的优势,并展望了云测试的发展方向.     

云环境下公平性优化的资源分配方法

针对云数据中心资源分配不均、效率不高、资源错位等问题,为了满足不同用户的需求,达到多种资源分配的公平性,实现资源的高效利用,提出了全局优势资源公平（GDRF）分配算法。GDRF算法采用多轮分配方式,即先通过用户已分配资源量确定分配资格,每轮再通过全局优势资源共享比和全局优势资源权重来确定具体的分配用户,分配过程充分考虑了资源的匹配情况,采用了max-min fairness思想的渐进填充方式,并且将多资源分配公平性统一度量模型运用到了算法中。实验基于一个Google集群数据模型与基于占优资源的多资源联合公平分配算法作了比较。实验结果表明,GDRF算法分配的虚拟机总量提高了12%,资源总利用率提高了0.5个百分点,公平评估值提高了约15%,并且该算法的资源组合分配的适应度较高,使得用户需求和供给更匹配。     

云计算环境下的软件测试研究

本文主要介绍了云计算环境下的软件测试相关内容,总结了云测试相对于传统测试的优势,并展望了云测试的发展方向.     

云存储环境下属性基加密综述*

属性基加密作为一种新型的密码方案,将用户私钥和密文与属性相关联,为解决云存储环境下数据安全共享、细粒度访问控制和安全存储等问题提供了一种解决思路。在对密钥策略属性基加密、密文策略属性基加密和混合策略属性基加密深入研究后,根据不同的功能扩展,针对隐藏访问结构、多授权机构、复杂计算安全外包、可搜索加密机制、属性撤销、叛徒追踪等重点难点问题进行了深入探讨研究。最后总结了现有研究工作的不足,并指出了未来的研究方向。     

云计算环境下数字档案馆运行架构

通过对云计算技术的应用研究,分析了数字档案馆引入云计算技术带来的好处,提出了云计算环境下数字档案馆的运行架构,推动了数字档案馆信息化建设的步伐,改进档案馆整体服务和管理模式,提升档案资源利用率和管理水平.同时对云计算在档案馆的应用,也起到了普及和推广的作用.     

基于元区间的云计算基础设施服务的资源分配算法研究

针对云计算中基础设施服务资源分配问题,提出了一种最佳分配决策算法。该算法通过估计待选元区间的资源配额参数,选择一个最小的满足用户应用要求的元区间,提高了基础设施服务资源的利用率。首先给出了基于元区间的基础设施服务模型,其次给出了云用户应用以及元区间资源之间的适应模型,最后提出了元区间决策算法并对该算法进行了系统地评价,该算法取得良好的效果。     

Trustworthy assurance of service interoperation in cloud environment

Cloud computing can be realized by service interoperation and its essence is to provide cloud services through network. The development of effective methods to assure the trustworthiness of service interoperation in cloud environment is a very important problem. The essence of cloud security is trust and trust management. Combining quality of service (QoS) with trust model, this paper constructs a QoS-aware and quantitative trust-model that consists of initial trust value, direct trust value, and recommendatory trust value of service, making the provision, discovery, and aggregation of cloud services trustworthy. Hence, it can assure trustworthiness of service interoperation between users and services or among services in cloud environment. At the same time, based on this model, service discovery method based on QoS-aware and quantitative trust-model (TQoS-WSD) is proposed, which makes a solid trust relationship among service requestor, service provider and service recommender, and users can find trustworthy service whose total evaluation value is higher. Compared to QoS-based service discovery (QoS-WSD) method, it is proved by the experiment for TQoS-WSD method that more accurate result of service discovery will be achieved by service requestor, while reasonable time cost is increased. Meanwhile, TQoS-WSD method strongly resists the effect of service discovery by untrustworthy QoS values and improves service invocation success-rate and thus assures trustworthiness of services interoperation.     

Holonic multilevel simulation of complex systems: Application to real-time pedestrians simulation in virtual urban environment

Simulation, which creates abstractions of the system is an appropriate approach for studying complex systems that are inaccessible through direct observation and measurement. The problem with simulation of great numbers of interacting entities is that it is difficult to create a reliable and tractable abstraction of the real system. Indeed, simulating large numbers of entities requires great computing resources. A solution to avoid this problem is to use macroscopic models. However, this type of model may be unavailable or not reliable for the problem at hand and it does not allow the observation of individual behaviours. In this paper, a multilevel simulation model is proposed to allow the use of both microscopic and macroscopic techniques. This model is based upon Holonic Multi-Agent Systems which offer a promising approach for developing applications in complex domains characterised by a hierarchical structure. The proposed approach provides a generic scheduling model for multilevel simulations: dynamically adapting the level of simulated behaviours while being as faithful as possible to the simulated model. It does not only manage the level of entities’ behaviour but also of behaviours classically assigned to the environmental part of a simulation. A set of physics-based indicators is also introduced to dynamically determine the most suitable level for each entity and to maintain the best trade-off between simulation accuracy and constraints (dependent on the model or the experimental context).     

Estimation of the execution time in real-time systems

Estimation of the worst-case execution time (WCET) of programs is an important problem for the development of real-time systems. In particular, the estimation of the WCET is a goal in the verification of aeronautical software specified in DO-178B/C. This is a difficult problem, and its exact solution is often practically impossible. This problem has been studied for many years; as a result, a lot of techniques for various cases have been developed. A survey of the available techniques for estimating the WCET is presented, which can be useful for choosing methods for solving particular problems.