基于PTIDES执行策略的调度算法

分析现有PTIDES执行策略调度算法,综合考虑事件的截止期和执行时间,改进传统最小空闲时间优先算法,将空闲时间作为事件调度优先权,提出零空闲时间优先PTIDES调度算法——ZSFPTIDES。实例分析表明,ZSFPTIDES调度算法能避免事件在处理过程中因得不到及时处理而夭折的现象,减小事件的抢占切换率,优化分布实时嵌入式系统的调度性能。     

Combined planning and scheduling in a divergent production system with co-production: A case study in the lumber industry

Many research initiatives carried out in production management consider process planning and operations scheduling as two separate and sequential functions. However, in certain contexts, the two functions must be better integrated. This is the case in divergent production systems with co-production (i.e. production of different products at the same time from a single product input) when alternative production processes are available. This paper studies such a context and focuses on the case of drying and finishing operations in a softwood lumber facility. The situation is addressed using a single model that simultaneously performs process planning and scheduling. We evaluate two alternative formulations. The first one is based on mixed integer programming (MIP) and the second on constraint programming (CP). We also propose a search procedure to improve the performance of the CP approach. Both approaches are compared with respect to their capacity to generate good solutions in short computation time.     

A DSS for integrated distribution of empty and full containers

A DSS integrating empty and full containers transshipment operations is presented, addressing the typically unbalanced export/import containers trading problem. The problem is modeled as a network, where nodes represent customers, leasing companies, harbors and warehouses, while arcs represent transportation routes. The underlying mathematical model operates in stages, first prioritizing and adjusting full containers demands considering available empty containers supplies, and then statically optimizing costs. Transportation routes are registered and dynamically controlled, cyclically, for a given time horizon. The DSS is flexible, allowing several parameters to be configured. Experimental examples using randomly generated parameters were conducted to evaluate the effectiveness of the system.     

Integrated control design for driver assistance systems based on LPV methods

The paper proposes a control design method for a driver assistance system. In the operation of the system, a predefined trajectory required by the driver with a steering command is followed. During manoeuvres the control system generates differential brake moment and the auxiliary front-wheel steering angle and changes the camber angles of the wheels in order to improve the tracking of the road trajectory. The performance specifications are guaranteed by the local controllers, i.e. the brake, the steering, and the suspension systems, while the coordination of these components is provided by the supervisor. The advantage of this architecture is that local controllers are designed independently, which is ensured by the fact that the monitoring signals are taken into consideration in the formalisation of their performance specifications. The fault-tolerant control can be achieved by incorporating the detected fault signals in their performance specifications. The control system also uses a driver model, with which the reference signal can be generated. In the control design, the parameter-dependent linear parameter-varyingmethod, which meets the performance specifications, is used. The operation of the control system is illustrated through different normal and emergency vehicle manoeuvres with a high-accuracy simulation software.     

An overview of the model integration process: From pre-integration assessment to testing

Integration of models requires linking models which can be developed using different tools, methodologies, and assumptions. We performed a literature review with the aim of improving our understanding of model integration process, and also presenting better strategies for building integrated modeling systems. We identified five different phases to characterize integration process: pre-integration assessment, preparation of models for integration, orchestration of models during simulation, data interoperability, and testing. Commonly, there is little reuse of existing frameworks beyond the development teams and not much sharing of science components across frameworks. We believe this must change to enable researchers and assessors to form complex workflows that leverage the current environmental science available. In this paper, we characterize the model integration process and compare integration practices of different groups. We highlight key strategies, features, standards, and practices that can be employed by developers to increase reuse and interoperability of science software components and systems.     

紧密衔接工序组联动的综合调度算法

由于现有的工序间存在紧密衔接条件的复杂产品综合调度问题, 采用的移动交换算法不易于软件实现且没有考虑移动工序后产生的连锁反应引起较高算法复杂度的问题, 提出将具有紧密衔接约束条件的工序组进行统一联动的综合调度算法.该算法利用将具有紧密衔接约束条件的工序分组的扩展加工工艺树模型, 按路径上属于工序组的工序个数多少确定所在路径工序组调度的次序, 通过降低对工序组的限制要求降低算法复杂度; 对于被调度工序组中各工序的前序工序, 按工序组中工序的加工顺序确定调度次序, 对某个工序的前序工序采用复杂度较低的拟关键路径法确定工序的调度次序; 调度完所有紧密衔接工序组后, 剩余的标准工序按拟关键路径法确定调度顺序; 采取工序首次适应调度算法调度标准工序和工序组, 由于工序组中工序采取按序紧密衔接的联动调度方式确定工序组的开始时间, 避免了二次调整, 进一步降低了算法复杂度. 分析和实例表明, 所提出的综合算法比以往算法复杂度更低, 调度结果更优且更易于实现.     

集成电路技术的发展

回顾了集成电路技术的发展历史,展望了集成电路未来的发展趋势。在微电子技术诞生和发展过程中具有一些里程碑式的发明,如:晶体管、集成电路、集成电路平面工艺、MOS器件、微处理器、光刻技术、铜互连工艺的发明等。集成电路技术一直并将继续以特征尺寸缩小、集成度提高的模式,按摩尔定律预测的指数增长率发展。随着器件特征尺寸逐渐缩小并逼近其物理极限,集成电路技术的发展将受到来自于材料、工艺和物理基础等方面的挑战,呈现出多维发展的趋势,这些挑战涉及了微电子学的理论基础。     

综合业务和区分业务比较研究

为了在Internet上提供有服务质量等级和保证的服务,现在已经提出的在传输层上的实现方案包括综合业务（Integtated Services）和区分业务（Differentiated Services)。本文分析了两种方案的体系结构、工作原理和服务类型,比较了二者在设计思想、实现机制、QoS特性等方面的差异和优缺点,介绍了两种模型相互结合的扩展体系结构及最新研究进展。     

面向对象技术在电信综合网管中的应用

论述了面向对象技术方法,以及如何在分析和设计电信综合网络管理中应用。     

Evolutionary Computation in Structural Design

The paper provides the results of preliminary research on the application of evolutionary computation to integrated structural design in which a complex design support tool automatically conducts both conceptual and detailed design. In the paper, a brief overview of the state of the art in evolutionary computation and its applications to structural design is provided. Next, Inventor 2000 is described, a unique research and structural design tool developed by the authors at George Mason University that combines an evolutionary computation component with a system for wind forces analysis, and a system for the analysis, design and optimisation of steel structures. The paper also presents the results of four structural design experiments conducted with Inventor 2000. The objective of experiments was to investigate various forms of evolutionary computation as applied to structure design. Finally, the paper provides the initial research conclusions and recommendations for further research.