On-line reschedule optimization for passenger railways in case of emergencies

This paper deals with a special case of the Vehicle Re-Scheduling Problem (VRSP) for passenger railways in case of emergencies. These emergencies arise when a service line is disturbed due to a huge and unexpected demand which exceeds the service line capacity. In order to provide a proper response to this type of emergency, an on-line optimization model based on a discrete-event simulation model is proposed to provide and support decisions about reassigning vehicles from other lines of the transport system to the disturbed line. The simulation model is based on a dynamic network loading model, a dynamic demand generation model, and a schedule-based service network. The on-line optimization model has been solved using two greedy heuristics which automatically generate near-optimal decisions about vehicle reassignments considering the total time in system for passengers as the minimization criterion. An experimental study, based on a synthetic network and the Madrid Regional Railway network, shows that the second proposed heuristic provides near-optimal reassignment decisions with short computation times compatible with real-time use.     

On the workload and ‘phaseload’ allocation problems of short reliable production lines with finite buffers

Serial flow or production lines are modeled as tandem queueing networks and formulated as continuous-time Markov chains to investigate how to maximize throughput or minimize the average work-in-process (WIP) when the total service time and the total number of service phases among the stations are fixed (these are the workload and ‘phaseload’ allocation problems, respectively). This paper examines both the effect of the kind of service time distribution on the optimal workload allocation in order to maximize throughput or minimize the average WIP of perfectly reliable production lines.

The new approach of this work is the differentiation of the number of service phases of the service time distribution which is assumed to be of phase type at all stations of the flow line and the placement of storage space (buffers) between any two successive stations in order to examine the effect of these factors to the form of the optimal workload vector t and the optimal service phase vector ph.     

基于SOA的企业IT架构

针对当前企业的信息化建设,提出并实现基于面向服务体系结构的企业应用集成系统架构,该架构采用企业服务总线无缝集成应用,支持流程服务编排,能进行组合服务开发,使企业可通过集成系统所提供的各种服务将其内部及企业间的应用集成在一起,并通过工作流的协调来互相调用,以实现一个完整的、跨组织的业务目标。     

基于多Agent的Web Service QoS模型

Web Service是采用面向服务的体系架构的基于标准的Web协议的软件构件,而Agent是一种在异构环境中自主行动以实现其设计目标的智能化软件实体。文章研究了利用Agent技术来进行动态发现、绑定符合用户QoS需求的Web Service,从而能够为用户提供更好的服务。     

信用卡刷卡服务的数字线路实现方法

分析了传统模拟线路的信用卡刷卡服务存在的问题，并提出了一人使用数字线路的方案及其实现技术，该方案具备协商速度快，传输质量高的优点。     

面向服务的Multi-Agent系统

本文以服务为中心,从面向服务的系统架构、中介服务协作机制、理性化的协商机制和智能交互等四个方面去建立开放、动态、面向服务的多Agent系统,以提高Agent的社会性智能。 [     

Digital twins to enhance the integration of ergonomics in the workplace design

Recently, human-centered design has become one of the most promising approaches for improving the entire production process design. During the design phase, among the main important aspects to investigate, ergonomic performance of the workplace (WP) plays a key role. It is well known that design errors can lead to significant delays in the design and engineering of a production process, especially when it is related to a complex system such as the assembly line of an automotive industry. Prediction of the ergonomic performance, which is often coarsely considered during the design phase, can represent a fundamental step in preventing ergonomic issues since the early design phase of a production process, avoiding also negative consequences on line balancing. Based on a concurrent engineering (CE) approach, the aim of this paper is to present a framework that uses digital twins of stations in order to minimise the time necessary to develop and design a new assembly line. The application of this procedure will allow avoiding the possibility of realising a line that reveals ergonomic problems and correcting design errors during the design phase and not just during the production phase. In this way, it is possible to achieve great advantages in terms of cost avoidance for the correction of the design errors and in terms of time to market, which will be significantly reduced. A digital twin of a real station of a Fiat Chrysler Automobiles (FCA) assembly line is presented to validate the numerical procedure and the design approach proposed in this paper. Finally, numerical results, regarding the evaluation of an ergonomic index, were compared with experimental ones achieved by analysing data collected during an experimental session.     

Using cost-aware transitions for reorganizing multiagent systems

Current approaches for reorganization in Multiagent Systems are mainly focused on providing solutions that maximize the organization utility but that do not include an in-depth evaluation of the reorganization impact in terms of costs. Reorganization requires determining the consequences of applying changes not only in terms of the benefits provided, but also measuring the reorganization costs as well as indirect impact that these changes have on in all the components of the organization. In this paper we present an infrastructure for reorganization based on transitions, which is focused on obtaining the transition with the highest potential for improvement in utility based on the transition costs. The approach provides an accurate measurement of the transition impact, since it determines the organization that is to be transition to as well as the changes required to carry out this transition. We show an example based on a tourist application in order to demonstrate that the measurement of the transition impacts taken by the service improve the organization performance. We also provide a performance evaluation of the service proposed and an example of a transition execution.     

车载CAN网络中直接NM逻辑环的实现

为实时监控车载网络中的节点,在使用控制器区域网络(CAN)总线的车载网络中,设计并实现一种基于OSEK/VDX规范直接网络管理(NM)的车载NM系统。由车载网关通过CAN总线收集各网络节点的故障信息,通过IPv6无线网络上传至远程故障诊断服务器,并将得到的故障处理信息下发至有关节点,实现车载CAN网络与远程故障诊断服务器的信息交互。测试结果表明,各网络节点上线后能快速建立稳定的逻辑环通信,并为远程故障诊断提供操作平台。     

Selecting job scheduling algorithms: beta distribution model for service times

Over a decade ago, Leonard Kleinrock developed a model for selecting best–performance scheduling algorithms for computer systems. The M/G/I queuing system used by Kleinrock requires that an estimate of the service–time probability distribution function (p.d.f.) be made in order to derive results. While methods of fitting service–time data to p.d.f.s are available, this paper argues that the use of a generalized beta distribution of the second type (GB2) in concert with the Kleinrock model reduces the need to estimate alternative models and avoids the consequences of arbitrarily imposing invalid assumptions on the data.     

终端服务技术的应用

终端服务是在Windows 2000/2003 Server产品系列中提供的一种技术,用以在一个远端的Windows2000 Server上执行应用程序或进行相应的管理工作。介绍了利用Windows2000终端服务技术,实现浏览工厂实时数据库的具体应用。     

高性能邮件过滤服务结构模型设计与实现

分析了MTA方式邮件过滤系统的业务流量和网络服务特点,以排队论为基础,建立了一个高性能邮件过滤服务模型,用于对邮件过滤系统的服务能力进行理论预测,并结合一个具体的应用场景,提供一个实例,其理论分析结果与实际情况相符,验证了该模型的有效性。     

Simultaneous location of a service facility and a rapid transit line

This paper presents a location problem on the plane where a single service facility and a rapid transit line have to be simultaneously located. The rapid transit line represents an alternative transportation line which can be used by clients whenever it provides a cost-saving or time-saving service, and it is given by a segment with fixed and known length. This type of problems has not previously been considered in the Location Theory literature, as we are only aware of the existence of models that consider the location of service facilities in the presence of an already located alternative transportation system or models dealing with the location of rapid transit lines to minimize the travelling time among a set of points. To solve this problem we will develop an algorithm based on some characterizations of the objective function behavior.     

自适应路由服务合成:模型及优化

当前新型网络应用不断涌现,用户对不同类型应用的通信需求也呈现出多样化和个性化的特点.面向用户频繁产生和变化的通信需求,网络服务提供商（Internet Service Provider,ISP）通常以不断地购买及部署大量新型的专用网络路由设备的方式来应对,导致其运营成本高昂,资源浪费严重,网络建设与发展的可持续性差.对此,本文从软件角度出发,考虑路由功能重用,通过选择合适的路由功能,在通信路径上为应用合成定制化的路由服务,满足用户差异化的需求.基于网络功能虚拟化（Network Function Virtualization,NFV）和软件定义网络（Software-DefinedNetworking,SDN）,本文提出了一种自适应路由服务合成机制,运用软件产品线技术,构建路由服务产品线,作为路由功能选择和路由服务优化的基础.基于机器学习,运用多层前馈神经网,构建路由服务离线模式和在线模式两阶段学习模型,对路由功能选择及组合进行持续学习和优化,实现路由服务的定制化目标,以提高用户的服务体验.进行了仿真实现,研究结果表明,本文提出的模型是可行和有效的.     

Line planning on tree networks with applications to the Quito Trolebús system

We discuss an optimization model for the line planning problem in public transport in order to minimize operation costs while guaranteeing a certain level of quality of service, in terms of available transport capacity. We analyze the computational complexity of this problem for tree network topologies as well as several categories of line operations that are important for the Quito Trolebús system. In practice, these instances can be solved quite well, and significant optimization potentials can be demonstrated.     

Designing for mobile value co-creation—the case of travel counselling

This paper focuses on the development of a mobile service as extension of travel agencies’ sales channels, fundamentally driven by the notion of value co-creation. Design goals are directly linked to the understanding of travel counselling as practical value co-creation and to the concern to progress this understanding throughout the travel customer cycle. Customers as well as travel agencies benefit from a mobile service rooted in value co-creation. Mobile service applications which target a service provision which furthermore is in line with the core competency of a travel agency (advice-giving and continuously accompany the customer) are scarce. Taking this as a starting point, we propose a mobile service and system design which provides a travel customer with continuing support on the trip, suitable to complement a lively, ongoing customer-firm interaction which enables the co-creation of value, ultimately targeting increased customer retention and loyalty.     

QoS and SLA aspects across multiple management domains: the SEQUIN approach

The aim of this work is to define and implement an end-to-end approach to quality of service (QoS), operating across multiple management domains and exploiting a combination of link layer technologies. The architecture for the Premium IP service is presented, which aims at offering the equivalent of an end-to-end virtual leased line service at the IP layer across multiple domains. Also, the results of the initial testing performed for the validation of the service and the provisioning model for Premium IP are described. The work presented has been carried out in the framework of SEQUIN, a European Commission-funded research project.     

Automatic test case generation for WS-Agreements using combinatorial testing

In the scope of the applications developed under the service-based paradigm, Service Level Agreements (SLAs) are a standard mechanism used to flexibly specify the Quality of Service (QoS) that must be delivered. These agreements contain the conditions negotiated between the service provider and consumers as well as the potential penalties derived from the violation of such conditions. In this context, it is important to assure that the service based application (SBA) behaves as expected in order to avoid potential consequences like penalties or dissatisfaction between the stakeholders that have negotiated and signed the SLA. In this article we address the testing of SLAs specified using the WS-Agreement standard by means of applying testing techniques such as the Classification Tree Method and Combinatorial Testing to generate test cases. From the content of the individual terms of the SLA, we identify situations that need to be tested. We also obtain a set of constraints based on the SLA specification and the behavior of the SBA in order to guarantee the testability of the test cases. Furthermore, we define three different coverage strategies with the aim at grading the intensity of the tests. Finally, we have developed a tool named SLACT (SLA Combinatorial Testing) in order to automate the process and we have applied the whole approach to an eHealth case study.     

From remote maintenance to MAS-based e-maintenance of an industrial process

One of the main consequences of the extended enterprise is the emergence of new forms of relationships between the customer and the supplier in order to ensure the quality of service of the object throughout the life cycle. Innovative communication and co-operation methods are needed to support these new relationships. The combination of modern information processing and communication tools, commonly referred to as tele-service, offers the technical support required to access remote information. Indeed, it is easier to transfer information and knowledge to different actors than to move an actor to the site. However, even if this technical support is necessary for information communication, it is insufficient to develop a co-operation-based working situation that involves many self-motivated customers and suppliers sharing a common goal. This synergy is an emergent property of the system as a whole, and it is not expected to be obtained as a simple sum of its components. For example, a challenging problem in the field of product manufacturing is to assist the operator in its decision-making, when the system functioning is degraded, to preserve the system under service at maximum (anticipation of the failure) while remaining it in a space of allowed operation (to avoid consequences of an error in judgement). That means an evolution from tele-service to e-work and e-maintenance in particular where the assistance to operator results from collaboration of maintenance processes and experts. Consequently, this paper examines some issues and challenges involved in the evolution from the tele-maintenance of an industrial platform to the e-maintenance, and then proposes a multi-agent system-based collaboration as a solution to implement the e-maintenance experiments.     

基于反馈平衡的多生产线调度算法与仿真

研究生产线平衡调度优化问题。传统的生产线产品调度中,由于生产线上的产品数量不定,造成生产线的负荷不平衡,容易造成生产线工序上产品堆积,导致生产线平衡能力下降,流水线发生阻塞。为了解决上述6问题,提出了一种反馈信息平衡的生产线产品调度算法。将产品在生产线上流动的顺畅情况,作为反馈信息传递给生产调度端。调度算法把各种信息作为指导后续生产线产品选择工序先后次序的依据,使得在生产线上负荷大幅增加的情况下,通过反馈信息改变产品调度顺序,使得生产线负荷达到平衡。实验结果表明,反馈信息平衡算法在产品负荷较大的情况下,有效地提高生产线的平滑指数,提高了生产线的效率。