Improve System Flexibility Research Articles

SLAE-CPS: Smart Lean Automation Engine Enabled by Cyber-Physical Systems Technologies.

In the context of Industry 4.0, the demand for the mass production of highly customized products will lead to complex products and an increasing demand for production system flexibility. Simply implementing lean production-based human-centered production or high automation to improve system flexibility is insufficient. Currently, lean automation (Jidoka) that utilizes cyber-physical systems (CPS) is considered a cost-efficient and effective approach for improving system flexibility under shrinking global economic conditions. Therefore, a smart lean automation engine enabled by CPS technologies (SLAE–CPS), which is based on an analysis of Jidoka functions and the smart capacity of CPS technologies, is proposed in this study to provide an integrated and standardized approach to design and implement a CPS-based smart Jidoka system. A set of comprehensive architecture and standardized key technologies should be presented to achieve the above-mentioned goal. Therefore, a distributed architecture that joins service-oriented architecture, agent, function block (FB), cloud, and Internet of things is proposed to support the flexible configuration, deployment, and performance of SLAE–CPS. Then, several standardized key techniques are proposed under this architecture. The first one is for converting heterogeneous physical data into uniform services for subsequent abnormality analysis and detection. The second one is a set of Jidoka scene rules, which is abstracted based on the analysis of the operator, machine, material, quality, and other factors in different time dimensions. These Jidoka rules can support executive FBs in performing different Jidoka functions. Finally, supported by the integrated and standardized approach of our proposed engine, a case study is conducted to verify the current research results. The proposed SLAE–CPS can serve as an important reference value for combining the benefits of innovative technology and proper methodology.

Impacts of optimal energy storage deployment and network reconfiguration on renewable integration level in distribution systems

Nowadays, there is a wide consensus about integrating more renewable energy sources-RESs to solve a multitude of global concerns such as meeting an increasing demand for electricity, reducing energy security and heavy dependence on fossil fuels for energy production, and reducing the overall carbon footprint of power production. Framed in this context, the coordination of RES integration with energy storage systems (ESSs), along with the network’s switching capability and/or reinforcement, is expected to significantly improve system flexibility, thereby increasing the capability of the system in accommodating large-scale RES power. Hence, this paper presents a novel mechanism to quantify the impacts of network switching and/or reinforcement as well as deployment of ESSs on the level of renewable power integrated in the system. To carry out this analysis, a dynamic and multi-objective stochastic mixed integer linear programming (S-MILP) model is developed, which jointly takes the optimal deployment of RES-based DGs and ESSs into account in coordination with distribution network reinforcement and/or reconfiguration. The IEEE 119-bus test system is used as a case study. Numerical results clearly show the capability of ESS deployment in dramatically increasing the level of renewable DGs integrated in the system. Although case-dependent, the impact of network reconfiguration on RES power integration is not significant.

Reconfigurable 4 × 4 multi‐port amplifier with switchable input and output matrices

This study presents a new reconfigurable 4 × 4 multi-port amplifier (MPA) configured by switchable matrices. The proposed structure adopts two 4 × 4 switchable matrices consisting of four unit-switching mode hybrid matrix (SMHM) where each SMHM is implemented with two 3 dB couplers and two single pole four throw (SP4T) switches. Comparing with previously reported MPA structures with fixed input and output relations which are exposed to performance degradation by power amplifier (PA) failure, the proposed structure can flexibly adjust signal paths. Also, the number of PAs used for signal amplification can be adjusted by controlling proper modes of SP4Ts in switchable matrices. For 4 × 4 structure, input signal can be amplified by a single PA, two PAs or all four PAs and then be outputted to only one port, two ports or all four ports. Thus, the proposed MPA structure can effectively improve system flexibility as well as reliability in case of PA failure. For the ease of verification, the proposed structure is tested at ISM band of 902–928 MHz.

Performance-Driven Load Balancing with a Primary-Backup Approach for Computational Grids with Low Communication Cost and Replication Cost

Computational grids provide a massive source of processing power, providing the means to support processor intensive applications. The strong burstiness and unpredictability of the available resources raise the need to make applications robust against the dynamics of grid environment. The two main techniques that are most suitable to cope with the dynamic nature of the grid are load balancing and job replication. In this work, we develop a load-balancing algorithm by juxtaposes the strong points of neighbor-based and cluster-based load-balancing methods. We then integrate the proposed load-balancing approach with fault-tolerant scheduling namely MinRC and develop a performance-driven fault-tolerant load-balancing algorithm or PD_MinRC for independent jobs. In order to improve system flexibility, reliability, and save system resource, PD_MinRC employs passive replication scheme. Our main objective is to arrive at job assignments that could achieve minimum response time, maximum resource utilization, and a well-balanced load across all the resources involved in a grid. Experiments were conducted to show the applicability of PD_MinRC. One advantage of our approach is the relatively low overhead and robust performance against resource failures and inaccuracies in performance prediction information.

Review on SOA-MZI-based photonic add/drop and switching operations

Semiconductor optical amplifier-Mach-Zehnder interferometer (SOA-MZI) is a technologically mature optical device that can be exploited for a wide range of operations on both amplitude and phase modulated signals, with performance limited by the carrier lifetime in the SOAs. Recent advances on SOA structures have demonstrated their suitability for high quality, ultra-fast photonic signal processing, making SOA-MZI a good candidate for elaborating signals in new generation high-capacity optical networks. Dynamic wavelength switching/routing and add/drop operations are expected to bring benefits in future optical networks in terms of improved system flexibility and efficiency. The capability of performing such operations directly in the optical domain can significantly reduce the number of opto/electrical and electro/optical conversions in the routing nodes, reducing their power consumption and their latency time. Moreover, since phase-shift keying (PSK) formats or other advanced modulation formats involving both amplitude and phase modulation, start to coexist in optical communication systems with the conventional on-off keying (OOK) modulation format, the availability of a single device, suitable for processing all these different signals, is mandatory. The SOA-MZI fits all these requirements for both OOK and constant-envelope phase-modulated signals, providing a compact and flexible solution. Here we review on the use of the SOA-MZI for carrying out alloptical switching operations, by realizing wavelength conversion and add/drop functionalities, both for OOK and differential binary phase shift keying (DPSK) signals up to 40 Gb/s. Power penalties lower than 2 dB are demonstrated in all cases.

Automatic Detection of Unsafe Dynamic Component Loadings

Dynamic loading of software components (e.g., libraries or modules) is a widely used mechanism for an improved system modularity and flexibility. Correct component resolution is critical for reliable and secure software execution. However, programming mistakes may lead to unintended or even malicious components being resolved and loaded. In particular, dynamic loading can be hijacked by placing an arbitrary file with the specified name in a directory searched before resolving the target component. Although this issue has been known for quite some time, it was not considered serious because exploiting it requires access to the local file system on the vulnerable host. Recently, such vulnerabilities have started to receive considerable attention as their remote exploitation became realistic. It is now important to detect and fix these vulnerabilities. In this paper, we present the first automated technique to detect vulnerable and unsafe dynamic component loadings. Our analysis has two phases: 1) apply dynamic binary instrumentation to collect runtime information on component loading (online phase), and 2) analyze the collected information to detect vulnerable component loadings (offline phase). For evaluation, we implemented our technique to detect vulnerable and unsafe component loadings in popular software on Microsoft Windows and Linux. Our evaluation results show that unsafe component loading is prevalent in software on both OS platforms, and it is more severe on Microsoft Windows. In particular, our tool detected more than 4,000 unsafe component loadings in our evaluation, and some can lead to remote code execution on Microsoft Windows.

Regulatory road maps for the integration of intermittent electricity generation: Methodology development and the case of The Netherlands

The envisaged increase in the share of electricity generation from intermittent renewable energy sources (RES-E) like wind and photovoltaics will pose challenges to the existing electricity system. A successful integration of these sources requires a cost-efficient use of system flexibility. The literature on the options to improve system flexibility, and thus the costs of successfully integrating intermittent electricity generating units, is still growing but what is lacking is an overarching systematic view on when to adopt which option in particular energy systems. This paper aims to bridge this gap in literature. We use existing insights on market and network integration of intermittent electricity sources within a regulatory road map framework. The framework allows policy makers and other electricity system stakeholders to arrive at a consistent strategy in dealing with integration issues over a longer period of time. In this contribution we present and explain the framework and apply it for the case of The Netherlands.

Fault-Tolerant Scheduling for Real-Time Tasks with QoS Requirements on Heterogeneous Clusters

PDF HTML阅读 XML下载 导出引用 引用提醒 异构集群系统中具有QoS 需求的实时任务容错调度 DOI: 10.3724/SP.J.1001.2011.03833 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家安全重大基础研究计划(973)(6136101); 国家高技术研究发展计划(863)(2008AA7070412) Fault-Tolerant Scheduling for Real-Time Tasks with QoS Requirements on Heterogeneous Clusters Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:容错调度是调度问题中一个重要的研究内容,是提高系统可靠性的有效手段.目前已有很多集群系统时任务的容错调度算法,但是这些算法都没有考虑到任务的QoS 需求问题.提出了一种异构集群系统中具有QoS 需求的实时任务容错调度算法FTQ(fault-tolerant QoS-based scheduling).该算法采用主版本/副版本(primary/backup, 简称PB)技术,综合考虑了任务的时间限制、任务的QoS 需求、系统的可靠性和系统资源的利用率,能够自适应地根据系统负载情况动态地调整任务的QoS 级别和副版本的执行模式,从而提高了系统的灵活性、可靠性、可调和资源的利用率.对系统的可靠性进行了定量分析,并将其引入到容错调度算法中,提高了系统的可靠性.同时,度过程中尽量提前主版本的开始时间,推迟副版本的开始时间,以使任务的副版本采用被动执行模式或者使任版本和副版本的重叠部分尽量少,提高了资源的利用率.此外,采用了副版本重叠技术,并分析了副版本的最晚时间及其约束条件,提高了任务的调度成功率.通过大量的模拟实验,对FTQ,NOFTQ 和DYFARS 算法进行了.实验结果表明,FTQ 算法的性能优于其他方法,具有更好的调度质量. Abstract:Fault-Tolerant scheduling, an effective means of improving a system’s performance, plays a significant role in scheduling research. Despite the fact that fault-tolerant scheduling has been extensively proposed for real-time tasks on clusters, QoS (quality of service) requirements for some tasks have not been considered. This paper proposes a fault-tolerance scheduling algorithm FTQ (fault-tolerant QoS-based scheduling) for real-time tasks with QoS needs on heterogeneous clusters. FTQ adopts the primary/backup model and takes the timing constraints of tasks, QoS requirements of tasks, reliability of systems, and system resource utilization into account. FTQ can adjust the QoS levels of real-time tasks and the execution schemes of backup copies to improve system flexibility, reliability, schedulability, and resource utilization. The system reliability is quantitatively measured and combined into FTQ, which improves the system performance. Meanwhile, FTQ strives to advance the start time of primary copies and delay the start time of backup copies to make backup copies adopt passive execution scheme, or decrease overlapping sections of primary and backup copies as much as possible to improve resource utilization. FTQ adaptively adjusts the QoS levels of tasks and the execution schemes of backup copies to attain a higher flexibility. The overlapping technology of backup copies is employed. The latest start time of backup copies and its constraints are analyzed. Compared with NOFTQ and DYFARS, FTQ shows obvious superiority with a higher scheduling quality proven by a considerable number of simulated experiments. 参考文献 相似文献 引证文献

QoS-Aware Fault-Tolerant Scheduling for Real-Time Tasks on Heterogeneous Clusters

Fault-tolerant scheduling plays a significant role in improving system reliability of clusters. Although extensive fault-tolerant scheduling algorithms have been proposed for real-time tasks in parallel and distributed systems, quality of service (QoS) requirements of tasks have not been taken into account. This paper presents a fault-tolerant scheduling algorithm called QAFT that can tolerate one node's permanent failures at one time instant for real-time tasks with QoS needs on heterogeneous clusters. In order to improve system flexibility, reliability, schedulability, and resource utilization, QAFT strives to either advance the start time of primary copies and delay the start time of backup copies in order to help backup copies adopt the passive execution scheme, or to decrease the simultaneous execution time of the primary and backup copies of a task as much as possible to improve resource utilization. QAFT is capable of adaptively adjusting the QoS levels of tasks and the execution schemes of backup copies to attain high system flexibility. Furthermore, we employ the overlapping technology of backup copies. The latest start time of backup copies and their constraints are analyzed and discussed. We conduct extensive experiments to compare our QAFT with two existing schemes-NOQAFT and DYFARS. Experimental results show that QAFT significantly improves the scheduling quality of NOQAFT and DYFARS.

Sizing CCHP Systems for Variable and Non-coincident Loads, Part 2: Operating Strategies

ABSTRACT One serious challenge to the implementation of combined cooling, heating and power (CCHP) systems is matching and sizing the system to strongly and frequently varying load conditions. Previous works, part 1 of this work in particular, have proven that while CCHPs have significant cost and performance advantages over traditional single-cycle systems, inadequate strategies, failure to address system flexibilities to accommodate load variations in particular, seem to have negatively impacted this promising technology. This paper discusses some techniques that can improve system flexibility for variable and non-coincident loads.

Distributed Automation: PABADIS versus HMS

Distributed control systems (DCS) have gained huge interest in the automation business. Several approaches have been made which aim at the design and application of DCS to improve system flexibility and robustness. Important approaches are (among others) the holonic manufacturing systems (HMS) and the plant automation based on distributed systems (PABADIS) approach. PABADIS deals with plant automation systems in a distributed way using generic mobile and stationary agents and plug and participate facilities within a flat structure as key points of the developed control architecture. HMS deals with a similar structure, but aims more at a control hierarchy of special agents. This paper gives a description of the PABADIS project and makes comparisons between the two concepts, showing advantages and disadvantages of both systems. Based on this paper, it will be possible to observe the abilities and drawbacks of distributed agent-based control systems.

System design of diagnostic subsystem in control networks

The current development of computer control and associated diagnosis has been made possible by the advent of microcomputers and microprocessors. This leads to the introduction of distributed systems based on the division of the whole system into partial, autonomous, interlinked subsystems each with its own control processor. Thus, improved system flexibility and reliability can be attained and a better solution to both control and diagnostics tasks is achieved. Dividing the tasks and bringing them closer to partial technological assemblies increases the rate of data processing; failures of a local processor do not necessitate putting the entire equipment out of operation. Diagnostic tasks are discussed in the present study of the 0th and 1st levels of the hierarchial division of the processor network.

Distributed Process Control: A Micro-Mini Marriage

Real-time process control problems in computer testing of automobile engines have led to the development of a low-cost microprocessor-based general-purpose minicomputer peripheral controller at the Chrysler Corporation Technical Computer Center in Detroit. Advantages of the new system over minicomputer-only or microcomputer-only systems include both improved system flexibility and better use of system resources. For example, because of their low cost and programmability, multiple microprocessors can be used to handle commonly encountered process control tasks. This feature is especially valuable in systems requiring frequent modifications because of constant changes in governmental standards or other parameters. Minicomputer-based systems, on the other hand, offer sophisticated executives, batch processing, and large data base capability. Besides combining these features, a central mini distributed microsystem offers the additional advantage of allowing the minicomputer to handle the loose coupling of two or more microcomputer tasks.