In-Situ Fabrication: Mobile Robotic Units on Construction Sites

Enabling the robotic fabrication of building elements directly on a construction site, in-situ fabrication is a radical and novel approach to the application of digital fabrication in architecture. Volker Helm of ETH Zurich describes how an on-site unit, developed with Fabio Gramazio and Matthias Kohler in the Architecture and Digital Fabrication department at the university, offers the first-ever generic robot with applications in a wide range of processes, providing the means of investigating the requirements and capacities involved in non-standardised fabrication.     

On the need for dynamic downlink intercell interference coordination for realistic Long Term Evolution deployments

Intercell interference is the main issue limiting the capacity of modern orthogonal frequency‐division multiple access based cellular networks. Recently, extensive research work has been carried out in this field, and intercell interference coordination techniques have been recognized as key enablers of current (and future) cellular technologies. In this article, (i) a comprehensive survey of the most representative contributions is provided together with (ii) a generic methodology to measure their actual merit. The performance of several interference avoidance strategies has been evaluated both from system and user point of view in the context of a Long Term Evolution (LTE)‐based network considering not only synthetic cellular scenarios but also realistic deployments. Our literature review indicates that there is a need for adaptive/operator‐customizable low‐complex intercell interference coordination (ICIC) schemes suitable for realistic LTE deployments. Results obtained by means of a comprehensive set of simulations corroborate and support this premise. In this article, it is shown that simultaneous gains in terms of spectral/energy efficiency and fairness can be achieved through dynamic mechanisms with respect to both classic hard reuse schemes and static ICIC techniques. Besides numerical results, a novel merit assessment methodology based on several weighted performance metrics is proposed. Our findings show that dynamic schemes outperform static techniques by around 20–35% in realistic deployments. Copyright © 2012 John Wiley & Sons, Ltd.     

Coordinated learning by exploiting sparse interaction in multiagent systems

Multiagent learning provides a promising paradigm to study how autonomous agents learn to achieve coordinated behavior in multiagent systems. In multiagent learning, the concurrency of multiple distributed learning processes makes the environment nonstationary for each individual learner. Developing an efficient learning approach to coordinate agents’ behavior in this dynamic environment is a difficult problem especially when agents do not know the domain structure and at the same time have only local observability of the environment. In this paper, a coordinated learning approach is proposed to enable agents to learn where and how to coordinate their behavior in loosely coupled multiagent systems where the sparse interactions of agents constrain coordination to some specific parts of the environment. In the proposed approach, an agent first collects statistical information to detect those states where coordination is most necessary by considering not only the potential contributions from all the domain states but also the direct causes of the miscoordination in a conflicting state. The agent then learns to coordinate its behavior with others through its local observability of the environment according to different scenarios of state transitions. To handle the uncertainties caused by agents’ local observability, an optimistic estimation mechanism is introduced to guide the learning process of the agents. Empirical studies show that the proposed approach can achieve a better performance by improving the average agent reward compared with an uncoordinated learning approach and by reducing the computational complexity significantly compared with a centralized learning approach. Copyright © 2012 John Wiley & Sons, Ltd.     

变电站直流系统保护级差配合特性分析

结合某500 kV变电站直流系统保护配置设计,计算直流系统各级短路电流,给出了直流系统各级保护配置额定值的选取原则。根据短路电流计算结果及直流断路器的配置情况,研究了500 kV变电站直流系统保护的级差配合特性。最后,总结了当前某变电站直流系统断路器保护配置存在的问题,给出了合理化改造建议。     

Application of a proposed overcurrent relay in radial distribution networks

This paper contains the application criteria and coordination process for a proposed overcurrent relay in a radial power system with feed from one or multiple sources. This relay uses independent functions to detect faults and to calculate the operation time. Also this relay uses a time element function that allows it to reduce the time relay operation, enhancing the backup protection. Some of the proposed approaches improve the sensitivity of the relay. The selection of the best approach in the proposed relay is defined by the needs of the application. The proposed protection can be considered as an additional function protection to conventional overcurrent relays.     

大规模风电接入下输电网扩展规划的启发式优化算法

提出了大规模风电接入下的输电网有功和无功扩展规划的解决方法。计及了风电与负荷的全年时序数据,并将网络设备投资的年值成本与方案在全年所有不满足安全约束场景下采取控制措施的成本之和最小作为规划目标。为了降低求解计算的复杂性,将原问题分解为网络设备投资决策与方案的控制措施成本评估2个子问题,二者借助原问题的规划目标进行总体协调。在此基础上,通过分析规划目标与问题本身的特性,设计了启发式的优化算法,明显地提高了计算速度。算例分析验证了所提方法的正确性和求解算法的有效性。     

硫酸四氨合铜的制备及成分测定

文章采用将CuSO4.5H2O溶于水,逐滴加入浓氨水至溶液变深蓝色,再滴加乙醇的方法制备硫酸四氨合铜（Ⅱ）晶体,并对其成分进行测定。结果表明,制备的硫酸四氨合铜（Ⅱ）中Cu2＋的平均百分含量为25.60%、NH3为27.52%、SO42-为38.46%、H2O为8.42%,实验测定值与理论值基本吻合。     

塑壳断路器的保护配合

在低压配电系统中,塑壳断路器是重要的保护用电气设备.介绍了塑壳断路器与导线、电动机及其他保护用电气设备之间的保护及配合关系,通过对这种配合关系的认识来获得最佳的保护匹配关系,充分发挥电气线路上电气设备和保护用电气设备的功用,达到安全、经济、合理选用断路器的目的.     

运输飞船仪表设备的人机工效设计

运输飞船仪表设备的人机工效设计的成功与否直接影响到运输飞船的使用效能、可操纵性、可维修性和航天员的安全性.运输飞船仪表设备人机工效设计的主要内容有按键布局、色彩设计、形态设计、显示器设计和操作力设计.     

国家电网公司协同办公系统研究与应用

为协调、推进并督促落实公司日常工作,保障政令畅通,整合国家电网公司系统资源,提升决策支持能力,强化信息枢纽能力,加强统筹协调能力,推动公司工作更加顺利、更有价值、更具形象。国家电网公司在"十一五"期间建设完成了覆盖公司总部、网省公司和基层单位的一体化综合办公管理平台,使办公信息在公司各单位实现纵向贯通、横向集成和高度共享。建立了规章制度体系、项目工作体系和技术保障体系,通过规章制度体系来规范项目的实施和应用,通过项目工作体系促进项目工作的有序开展,通过技术保障体系支撑系统的正常运行;建成公司层面的文件中心、任务中心、知识中心和档案中心。