全球移动通信发展趋势

新世纪初，在全球电信业普遍下滑的大环境下，移动通信仍继续增长。虽然增长速度比90年代要慢些，但是在新千年的头两年里，全球大约共新增移动电话5亿部，此数超过了截至2000年初移动电话销售的总数。这无疑给电信业注射了一支强心针。移动通信的发展总是超过了我们的预期。在     

Network evolution and multimedia communication

The survey analyzes the communication requirements of distributed multimedia applications. To understand the ongoing evolution of networking, we must consider how current and new networking technologies support these requirements. In addition to the functional aspects, the survey investigates how the new technologies blend with existing infrastructures. It concludes with a brief discussion of the higher layer multimedia communication issues     

超大城市城域光传送网演进方案探讨

业务创新推动网络要求的持续变化,大带宽、低时延、简运维无疑是对城域光传送网提出的新要求,本文聚焦全业务发展趋势（家庭业务、集客业务、无线业务、新业务）结合网络现状分析及未来业务发展诉求,给出城域光传送网演进方案。     

A stochastic evolution algorithm based 2D VLSI global router

In this work we present a global router that uses the features of the Stochastic Evolution (StocE) algorithm to perform the rip-up and re-route (R&R) process. The unique features of the proposed global router are its simple design and ability to produce good results. It has two main components: (i) maze routing with framing (MRF) that act as a means of routing the nets; and (ii) a StocE algorithm that controls the R&R process and adjusts the parameters of the MRF method. This work shows that the StocE algorithm can perform the net selection in the R&R process and also adjust the parameter values of the MRF method in order to successfully solve 2D global routing problems. The performance of the proposed global router on the ISPD98 and ISPD2008 benchmarks was found to be better than some of the existing global routers.     

三星进军网络安全——以革新技术创造全球网络安全空间

三星计算机安全公司是韩国三星集团下属分公司。三星集团将三星SDS、Unitel、三星电子、S1以及三星科技研发中心等三星集团五大机构的信息安全技术整合一体,于2000年3月20日在韩国汉城成立三星计算机安全公司,专门从事信息安全产品的研发、技术支持以及市场拓展,尤其是针对海外市场的拓展。韩国计算机安全公司成立后,又于同年4月在美国成立分公司,11月在中国北京成立代表处。 三星计算机安全公司服务范围包括:提供全方位的信息安全解决方案、信息安全服务以及信息安全顾     

Multimedia technology in context

As with any potentially disruptive business process, the key starting point for multimedia application development is the users: who are they, and what do they want to do? I examine usability in digital media management, with special attention to searches, which most users employ repeatedly. My insights are drawn from almost a decade of experience with a business-to-business multimedia search application, which has evolved into the photography portal PictureQuest.     

A survey on addressing privacy together with quality of context for context management in the Internet of Things

Making the Internet of Things (IoT) a reality will contribute to extend the context-aware ability of numerous sensitive applications. We can foresee that the context of users will include not only their own spatio-temporal conditions but also those of the things situated in their ambient environment and at the same time, thanks to the IoT, those that are located in other remote spaces. Consequently, next-generation context managers have to interact with the IoT underlying technologies and must, even more than before, address both privacy and quality of context (QoC) requirements. In this article, we show that the notions of privacy and QoC are intimately related and sometimes contradictory and survey the recent works addressing them. Current solutions usually consider only one notion, and very few of them started to bridge privacy and QoC. We identify some of the remaining challenges that next-generation context managers have to deal with to favour users’ acceptability by providing both the optimal QoC level and the appropriate privacy protection.     

Community media in the context of European media policies

In the last three decades the emergence and development of community media across Europe has been mainly characterised by the political and social contexts at the national levels and, consequently, the sector is shaped by a range of opportunities and challenges that depend on the status of current policy, legislation and funding regimes in each country. Where at the pan-European level, since the 1970s, the Council of Europe has been supporting community media as a means for pluralism and diversity in the media, as well as a tool to promote social cohesion, in the European Union audiovisual and media policies, community media have been largely overlooked. In 2008 the Culture and Education Committee of the European Parliament promoted a report to support community media in the Union, signalling a new development pursuing to influence media policy discussion in the member states. This article aims to trace the contours of community media’s route across European media policies to assess how its practice has been shaped so far and discuss the emerging issues that are likely to influence its near future.     

Network control: The other gating factor for network evolution to broadband

An invited contribution from a member of the editorial board, or another respected figure in the profession, in which a particular viewpoint is put forward giving an informed, but not necessarily conventional, opinion on a major topic in the field of communication systems..     

Mobile user recovery in the context of Internet transactions

With the expansion of Web sites to include business functions, a user interfaces with e-businesses through an interactive and multistep process, which is often time-consuming. For mobile users accessing the Web over digital cellular networks, the failure of the wireless link, a frequent occurrence, can result in the loss of work accomplished prior to the disruption. This work must then be repeated upon subsequent reconnection - often at significant cost in time and computation. This "disconnection-reconnection-repeat work" cycle may cause mobile clients to incur substantial monetary as well as resource (such as battery power) costs. In this paper, we propose a protocol for "recovering" a user to an appropriate recent interaction state after such a failure. The objective is to minimize the amount of work that needs to be redone upon restart after failure. Whereas classical database recovery focuses on recovering the system, i.e., all transactions, our work considers the problem of recovering a particular user interaction with the system. This recovery problem encompasses several interesting subproblems: (1) modeling user interaction in a way that is useful for recovery, (2) characterizing a user's "recovery state", (3) determining the state to which a user should be recovered, and (4) defining a recovery mechanism. We describe the user interaction with one or more Web sites using intuitive and familiar concepts from database transactions. We call this interaction an Internet transaction (iTX), distinguish this notion from extant transaction models, and develop a model for it, as well as for a user's state on a Web site. Based on the twin foundations of our iTX and state models, we finally describe an effective protocol for recovering users to valid states in Internet interactions.     

Image processing in the context of a visual model

A specific relationship between some of the current knowledge and thought concerning human vision and the problem of controlling subjective distortion in processed images are reviewed.     

Provision of unified IN functionality in the context of IMS

The IP Multimedia Subsystem (IMS) represents an attempt for networks convergence, allowing users of rich-content applications to communicate through any access network type. In the near future, IMS is expected to give operators and content providers the flexibility to exploit a multitude of new communication applications in a harmonized communication environment of heterogeneous IP networks. However, despite its merits, the standardization process of IMS networks is lagging behind, leaving harmonization issues of services provisioning, open. In this effort, main hindering factor is the existence of similar implementations customized per network technology. Particularly in what concerns the Intelligent Network (IN) services, these are provided in mobile networks by CAMEL (Customised Applications for Mobile networks Enhanced Logic) and in fixed networks by INAP (IN Application Part). With regard to this problem, the present work introduces a method for integrating into the context of IMS communications all types of IN logic that nowadays are available only in legacy networks. The key element of this method is a service interrogation logic, called IN-OAG (IN-Open Architecture Gateway), which can be integrated on the P-CSCF (Proxy-Call Service Control Function) component of IMS, as an enhancement for supporting IN interoperability. IN-OAG is dedicated to implementing interoperability between the core IMS and mobile, wireless or fixed networks. The functionality of the proposed architecture is shown through several example scenarios.     

Photovoltaics in an architectural context

In well‐populated areas, such as western Europe, PV is often integrated into the building envelope. Despite the fact that there are many examples showing that PV can be an aesthetically neutral or visually attractive element in architecture, many BIPV systems display few architectural qualities. But if well applied, PV can increase a building's character and value. Within Task 7 of the IEA PVPS programme a team of experts with an architectural background studied which key requirements needed to be complied with (design criteria for good‐quality PV projects) in order to produce successful PV integration. These criteria are discussed in the article. PV is not automatically considered an indispensable material in architectural terms. This is why, no matter how well it is integrated, PV remains an ‘added’ element. Architects can take this as their starting point and can use one of the design approaches that are presented in the article. These criteria for incorporating PV in the building design and the design criteria for good‐quality PV projects are important to architects and architectural critics in determining why a BIPV project, be it their own design or that of a colleague, is or is not aesthetically pleasing. This offers learning opportunities and reasons for follow‐up or improvement options. Architects who apply PV in a well‐thought‐out way can make their clients very happy, and thereby contribute to a greater acceptance of PV technology. Copyright © 2004 John Wiley & Sons, Ltd.     

Optimization method versus E-pulse method in the context of targetdiscrimination

The performances of the optimization method and the extinction pulse method are evaluated for idealized data as well as experimental data from scaled-model targets. Although both methods use the late-time response to discriminate targets, the discriminant waveform is synthesized differently; from the target pole singularities in the E-pulse method, and from an energy maximization in the optimization method. Responses from waveforms synthesized using calculated wire data and laboratory measured data are presented, and the early-time energy confinements produced by the two methods are found to be generally comparable. The robustness of the optimization and E-pulse methods in the presence of noise is demonstrated by results for calculated and measured data     

Space-diversity issues in the context of a B-ISDN-oriented indoorradio environment

A first assessment of the applicability and the tradeoffs involved in a switched (antenna) diversity approach is presented here as seen in the context of a future indoor wireless network operating in the mm-wavelength radio spectrum targeted to provide radio access to asynchronous transfer mode local area networks (ATM LAN's) and broadband integrated services digital networks (B-ISDN). Measurements conducted at 21.6 GHz are used to examine the gain variation of switched-diversity alternatives in terms of cumulative distribution functions. The performance of a two-branch post-detection code diversity combining scheme under Rayleigh fading conditions is also included for purposes of comparison. The results of our work here confirm the hypothesis that the choice of the employed antenna diversity technique in combination with the selected micro-cellular architecture have significant effects on both the throughput and the measured performance of future radio links     

Weak electromagnetic fields and cancer in the context of riskassessment

We review the issue of possible health effects from low-level nonionizing electromagnetic fields from the perspective of risk assessment, in particular cancer risk assessment. We define risk and describe briefly the weight-of-evidence criteria used by agencies (in particular the Environmental Protection Agency and the International Agency for Research on Cancer) in their classification of carcinogens. Last, we review three issues related to electromagnetic fields and cancer: residential exposure to power-frequency magnetic fields and childhood leukemia, occupational exposure to power-frequency magnetic fields and breast cancer, and exposure to low-level radio-frequency fields from communications antennas and cancer. These case histories were chosen to illustrate the problematic nature of the scientific evidence, not to present a comprehensive survey of the entire field. In all of these cases, the evidence in support of links between the fields and cancer is weak and inconsistent. However, in view of the difficulties that are inherent in cancer risk assessment and in proving the negative in general, it is not possible to prove that no such links exist. Moreover, there have been numerous reports of links between nonionizing electromagnetic fields and diverse other health endpoints, so controversy about such links is likely to continue indefinitely. This conundrum may require a more sophisticated understanding of risk and risk communication by people and organizations that are professionally involved with electrotechnology     

Crystal structure prediction in the context of inverse materials design

Inverse materials design tackles the challenge of finding materials with desired properties,tailored to specific applications,by combining atomistic simulations and optimization methods.The search for optimal materials requires one to survey large spaces of candidate solids.These spaces of materials can encompass both known and hypothetical compounds.When hypothetical compounds are explored,it becomes crucial to determine which ones are stable (and can be synthesized) and which are not.Crystal structure prediction is a necessary step for assessing theoretically the stability of a hypothetical material and,therefore,is a crucial step in inverse materials design protocols.Here,we describe how biologically-inspired global optimization methods can efficiently predict the stable crystal structure of solids.Specifically,we discuss the application of genetic algorithms to search for optimal atom configurations in systems in which the underlying lattice is given,and of evolutionary algorithms to address the general lattice-type prediction problem.