大数据环境下图书馆数据来源与采集研究

随着图书馆数字化、网络化的发展,数据挖掘及数据分析技术的层出不穷,通过对图书馆产生的大量的用户行为信息记录、资源信息和服务信息数据的分析和挖掘,为图书馆的发展提供了重要的依据,本文针对图书馆各种软件、系统及资源数据建设现状,总结了大数据环境下图书馆可以采集的数据,为大数据环境下图书馆数据分析与挖掘提供借鉴和参考.     

2.4GHz频段家庭电磁环境下蓝牙性能分析与实验

对工科医(ISM)频段的家庭电磁环境进行了分析与测量,给出了测试波型与数据.应用一个通用的同频段干扰模型,对蓝牙无线网络在此电磁环境下的性能进行了仿真.测试了蓝牙无线网络在无线局域网(WLAN)和微波炉干扰下的性能影响.实验结果表明:蓝牙无线网络在家庭电磁环境干扰下性能最高下降了42%,工作受到了严重影响.说明如今的家庭电磁环境十分恶劣,应给予足够的重视.     

前馈网络的信息泄漏与收集

提出了一种攻击单、多输出前馈网络的新方法，该方法的基本思想是利用最大谱原则，充分收集输入信息的线性组合和输出信息的线性组合的相关性，由输出序列构造出与输入序列具有更大相关件的序列，从而达到提高相关分析成功率的目的。文中最后给出了具体的应用实例。     

PCs and workstations

The long-anticipated union of PCs and workstations began in earnest in 1993, ushering in another era in computing. Each group ceded the central processor slot to the latest chips based on reduced-instruction-set computing (RISC): Alpha, MIPS, PA-RISC, PowerPC, and microSparc. Complex-instruction-set computing (CISC), meanwhile, is not dead, certainly not in notebook computers and microcontroller-based systems; but its future in the general-purpose computers of the next millennium is moot. Like distributed client-server computing, multimedia and interactive video communications are new pillars on which modern businesses are now being built. Traditional office equipment will tie in to computers easily in 1994, and companies will shift to operations that are fully integrated yet distributed throughout the enterprise. This paper discusses multimedia systems, active matrix screens, and notebooks displaying in 3D     

Active networks as a developing and testing environment for network protocols

Active Networks is a modern network approach in which pieces of code can be downloaded and executed on network devices, affecting in this way their behavior. This approach alters the philosophy of a computer network, makes it resemble to a distributed system and affects not only network protocols, services or applications, but also high-level mechanisms and procedures. One of the affected procedures is the development and testing of new protocols. By exploiting active network properties the development of a network protocol can be simplified to software development. Expensive and time-consuming hardware implementations are avoided, while the code can be developed, shared and tested by individual researchers. Testing can be performed on actual conditions instead of using inaccurate simulations. Early implementations of the protocol, which can be modified easily while the protocol evolves, can be used to obtain useful feedback. This paper describes our experiences of developing and testing of some of theietf cops family protocols in an Active Environment.     

Automated network selection in a heterogeneous wireless network environment

Service delivery in a heterogeneous all-IP wireless network environment requires the selection of an optimal access network. Selection of a non-optimal network can result in undesirable effects such as higher costs or poor service experience. Network selection in such an environment is influenced by several factors, and currently a complete solution is not available to solve this problem. This article describes a comprehensive decision making process to rank candidate networks for service delivery to the terminal. The proposed mechanism is based on a unique decision process that uses compensatory and non-compensatory multi-attribute decision making algorithms jointly to assist the terminal in selecting the top candidate network     

Web网络环境下的语义检索平台设计与分析

在Web网络环境下,传统信息检索方法仅依据简单的字和词进行匹配,未考虑知识的描述、处理以及理解等性能,检索质量和效率低。因此,设计了基于Web的语义检索平台,其由数据层、数据访问层、业务逻辑层、控制层和人机接口层组成。业务逻辑层依据数据访问层操作数据,并将数据反馈给控制层;控制层是用户申请和业务逻辑操作间的调控器;人机接口层是用户同检索平台间实现交互的桥梁,用户通过该层中的操作界面完成信息的检索。分析Jena在语义检索平台中的作用,并在软件设计部分,分析通过Jena实现语义检索平台数据检索的过程和其中的关键代码。实验结果表明所设计的语义检索平台具有较高的检索质量和效率。     

Engineering workstations and PCs

This report looks at client-server demands, low-cost workstations, network backup, and optical disc drives. A major reason for the client-server shift is economic. People can get a lot more computing power for their money if they use networks of workstations and PCs effectively rather than terminals tethered to a single mainframe. So it is not surprising that there is the concomitant shift to lower-cost workstations. Today, the cost of workstations continues to drop, while the power of PCs is on the increase     

时延受限的移动sink数据收集算法

在实时性要求比较高的应用中,时延要求限制了sink的移动速率与移动轨迹,sink的移动速率限制了节点与sink的通信时间,因此很难兼顾时延要求与数据收集效率。提出一种时延受限的移动sink数据收集算法MSDC,在低能耗缓存区内找到一条sink的最优移动轨迹,在有限的时间限制内利用sink的移动性来提升传感器网络的数据收集性能。仿真结果表明,与已有算法比较,该方案能够提高网络数据采集量,降低能耗,延长网络生命周期。     

Of workstations and supercomputers

Factors to consider when choosing between workstations and supercomputers are identified. Applications and computers are categorized, and speed requirements as a driving force in computer development are examined. It is shown how to analyze an application to determine the type of system that can best solve the problem, and the types of problem for which workstations are best are discussed     

Collision analysis for a multi-Bluetooth picocells environment

Operating in the unlicensed 2.4-GHz ISM band, a Bluetooth piconet will inevitably encounter the interference problem from other piconets. With a special channel model and packet formats, one research issue is how to predict the packet collision effect in a multi-piconet environment. In an earlier work (El-Hoiydi (2001)), this problem is studied, but the result is still very limited, due to the assumptions that packets must be single-slot ones and that time slots of each piconet must be fully occupied by packets. A more general analysis is presented in this work by eliminating these constraints.     

Ant-based routing and QoS-effective data collection for mobile wireless sensor network

Mobility management in mobile wireless sensor networks (MWSNs) is a complex problem that must be taken into account. In MWSN, nodes move in and out of the network randomly. Hence, a path formed between two distant nodes is highly susceptible to changes due to unpredictable node movement. Also, due to the limited resources in WSN, the paths used for data transmission must be tested for the link quality and time consumed for data forwarding. In order to solve these issues, in this paper, an ant-based routing protocol with QoS-effective data collection mechanism is proposed. In this protocol, the link quality and link delay are estimated for each pair of nodes. Link quality is estimated in terms of packet reception rate, received signal strength indicator, and link quality index. A reliable path is chosen from the source to the destination based on the paths traversed by forward ants and backward ants. Then, if the link is found to be defective during data transmission, a link reinforcement technique is used to deliver the data packet at the destination successfully. The mobile robots collect the information with high data utility. In addition, each mobile robot is equipped with multiple antennas, and space division multiple access technique is then applied for effective data collection from multiple mobile robots. Simulation results show that the proposed routing protocol provides reliability by reducing the packet drop and end-to-end delay when compared to the existing protocols.     

Security considerations in a network management environment

Considers the security aspects of communication between two management processes operating in different management domains; identifies two major risks: the security of information exchanged during the management association, and control of access to the management information base (MIB); and enumerates the various threats that must be guarded against and possible methods of attack. Security techniques, including symmetric and public key cryptosystems, are employed in the design of a method of achieving a secure management association. A scheme of authorization control for MIB access is developed. The management of an open system's network resources takes place in the context of a management association. The resources themselves are controlled by an agent process which presents a view of these resources to the outside world as a number of managed objects, each of which contains a number of attributes. The collection of objects presented to the outside world by the agent is known as the MIB. A manager process regulates the operation of the managed resources by engaging in a management association with the agent and instructing it to carry out simple operations on elements of the MIB. Within a single management domain where all processing nodes and network links are under the control of the same administration, security is not such a critical issue. However, when the management association takes place across the boundary between two separate management domains, and make use of public data networks, security issues must be considered in greater detail     

Authentication protocols for mobile network environment value-addedservices

The secure provision of mobile computing and telecommunication services is rapidly increasing in importance as both demand and applications for such services continue to grow. This paper is concerned with the design of public key based protocols suitable for application in upcoming third-generation mobile systems such as the Universal Mobile Telecommunications Service. Candidate protocols are considered for the authentication of a mobile user to a value-added service provider with initialization of a mechanism enabling payment for the value-added service. A set of goals for such a protocol are identified, as are a number of generic attacks; these goals and attacks are then used to evaluate the suitability of seven candidate third-generation user-to-network authentication protocols. Many of these candidate protocols are shown to have highly undesirable features     

无线传感器网络数据收集方案改进方法研究

当前,无线传感器网络成为研究热点,其数据的传输安全性受到广泛关注。文章提出了一种基于改进的LEACH协议的无线传感器网络数据收集方案,降低了数据传输过程中的能量损耗。     

Real-world environment models for mobile network evaluation

Simulation environments are an important tool for the evaluation of new concepts in networking. The study of mobile ad hoc networks depends on understanding protocols from simulations, before these protocols are implemented in a real-world setting. To produce a real-world environment within which an ad hoc network can be formed among a set of nodes, there is a need for the development of realistic, generic and comprehensive mobility, and signal propagation models. In this paper, we propose the design of a mobility and signal propagation model that can be used in simulations to produce realistic network scenarios. Our model allows the placement of obstacles that restrict movement and signal propagation. Movement paths are constructed as Voronoi tessellations with the corner points of these obstacles as Voronoi sites. Our mobility model also introduces a signal propagation model that emulates properties of fading in the presence of obstacles. As a result, we have developed a complete environment in which network protocols can be studied on the basis of numerous performance metrics. Through simulation, we show that the proposed mobility model has a significant impact on network performance, especially when compared with other mobility models. In addition, we also observe that the performance of ad hoc network protocols is effected when different mobility scenarios are utilized.     

强负荷网络环境下的大型负载分析平台的设计与优化

强负荷网络环境下,传统大型负载分析平台存在资源占用率高、效率低等问题。因此,设计了基于Web服务器集群的大型负载分析平台,确保在强负荷网络环境下,通过Web服务器集群提供高可用的服务,实现负载均衡。分析了负载分析平台运行流程,基于该流程设计了负载分析平台的总体结构,平台通过接收模块接收用户申请,再采用分类模块对用户申请进行分类,通过分发模块向用户申请分配相应的进程。信息收集模块将不同服务器节点的运行状态反馈给方案模块,促使方案模块融合神经网络和遗传算法对不同节点的资源分配状态进行设置。分析模块对总体负载分析平台中的不同服务器节点进行监测,分析不同节点是否存在故障以及节点的负载是否均衡。软件设计中给出了负载分析平台模块功能结构,以及信息采集代码设计。实验结果表明,所设计负载分析平台的CPU平均利用率和任务平均处理时间都较优,并且具有较好的吞吐量。     

Satellite network management in a crowded spectral environment

The domestic satellite industry has grown from the start-up phase to a position of relative maturity under a variety of flexible regulatory policies. This article focuses on two areas of policy which are critical to future growth in the industry. First, the existing policy governing orbital assignments is reviewed and recommendations presented for future policy changes. Second, the article stresses the need for policies to insure that all participants can operate in an environment free of undue frequency interference. The article concludes that the public interest motivation behind these policies is best served by a balance between regulatory oversight and industry self-help.     

Technology 1992-PCs and workstations

Developments during the past year are reviewed. As prices continued to fall and performance continued its upward trend, the line between PCs and workstations blurred further. Pen-based computers gained prominence, IC cards got a boost when the PCMCIA trade association came out with version 2.0 of its memory card standard, and multimedia stands poised to become a major market force. A, strategic alliance between Apple and IBM made news, and demand for the relatively new 2.5 in disk drives zoomed     

Performance evaluation of MADM-based methods for network selection in a multimedia wireless environment

Wireless Networks - As mobile devices have become more affordable, easy to use and powerful, the number of mobile users and their bandwidth demands have experienced a significant growth....