伪欧氏空间中直纹面的性质

讨论伪欧氏空间中的直纹面。利用活动标架法研究了直纹面的一些性质,包括极小性,全可展性,全测地性和全脐性,给出了直纹面是全可展性的一组充要条件,同时得到,Rnv+1中的k+1维直纹面M是全测地的充要条件是它是极小的且全可展的。特别,若M的生成空间是类空的或类时的,则当k≥2时,M全测地与全脐等价。本文还讨论了Rnv+1中直纹超曲面的Gauss-Kronecker曲率G,当n≥3时,G=0。这与低维情形绝然不同,在R3或R31中只有当直纹面是可展时,高斯曲率才为0。

Global Major Progress and Trends in the Implementation of Agenda 21

This paper summarizes, from a global perspective, the major progress in the implementation of the Agenda 21 since the UN Conference on Environment and Development. The results show that global economy has achieved a substantial growth, and positive progress has been made in poverty eradication, urbanization, and conservation and intensive use of natural resources. However, relevant international conventions and commitments have not yet been completely fulfilled. The paper further analyzes the current major challenges and future trends of global sustainable development. It is argued that there are three major challenges:1) fatal global environmental issues posing an increasing threat to human survival; 2) more and more severe global competition for developing spaces; and 3) issues highlighting global people's livelihood. There are four trends of global sustainable development:1) sustainable development will further turn from concept into global action; 2) green will be the main trend of global development; 3) emerging developing countries will become the main driving force of global sustainable development; and 4) international relations in the field of sustainable development will turn to competitive co-operation.

China’s National Research Project on Future Internet: Objectives, Ideas, and Progresses

The Internet today was designed in 1970s and is suffering various serious issues such as security, mobility and scalability. In order to deal with these issues, a national research project, supported by the prestigious National Basic Research Program (also called the "973 program") of China, was launched in May 2007. This project adopts a clean-slate approach and aims to design a novel future Internet that not only inherits the merit of the Internet today but also overcomes the drawbacks of the current Internet. In this paper, we make an overview of this project with a focus on its objectives, basic ideas, and progresses. Although this is a basic research project, its success will bring significant benefits to China as well as all other countries in the world.

A watershed-based adaptive knowledge system for developing ecosystem stakeholder partnerships

This study proposes a Watershed-based Adaptive Knowledge System(WAKES) to consistently coordinate multiple stakeholders in developing sustainable partnerships for ecosystem management.WAKES is extended from the institutional mechanism of Payments for Improving Ecosystem Services at the Watershed-scale(PIES-W).PIES-W is designed relating to the governance of ecosystem services flows focused on a lake as a resource stock connecting its inflowing and outflowing rivers within its watershed.It explicitly realizes the values of conservation services provided by private land managers and incorporates their activities into the public organizing framework for ecosystem management.It implicitly extends the "upstream-to-downstream" organizing perspective to a broader vision of viewing the ecosystems as comprised of both "watershed landscapes" and "marine landscapes".Extended from PIES-W,WAKES specifies two corresponding feedback:Framework I and II.Framework I is a relationship matrix comprised of three input-output structures of primary governance factors intersecting three subsystems of a watershed with regard to ecosystem services and human stakeholders.Framework II is the Stakeholder-and-Information structure channeling five types of information among four stakeholder groups in order to enable the feedbacks mechanism of Framework I.WAKES identifies the rationales behind three fundamental information transformations,illustrated with the Transboundary Diagnostic Analysis and the Strategic Action Program of the Bermejo River Binational Basin.These include(1) translating scientific knowledge into public information within the Function-and-Service structure corresponding to the ecological subsystem,(2) incorporating public perceptions into political will within the Serviceand-Value structure corresponding to the economic subsystem,and(3) integrating scientific knowledge,public perceptions and political will into management options within the Value-and-Stakeholder structure corresponding to the social subsystem.This study seeks to share a vision of social adaptation for a global sustainable future through developing a network to adopt contributions from and forming partnerships among all ecosystem stakeholders.

Work safety and sustainable development in enterprise

The nature of work safety and the way insisting on sustainable development in enterprise were analyzed. It indicates that problem of work safety in enterprise is closely related to the public’s consciousness, to the development of science and tech- nology, and to the weakening of safety management during the economic transition pe- riod. However, it is the people’s questions concerned in the final analysis for the forming and development of the problem of work safety. Therefore, in order to solve the problem of work safety radically, the most basic way of insisting on the sustainable development in safety administration is to do a good job of every aspect about people. We should im- prove all people quality in science and culture and strengthen their safety and legal consciousness to form correct safety value concept. We should fortify safety legislation and bring close attention to approach and apply new safety technology.

Review and Prospect of the UN Efforts for Sustainable Development

The present paper reviews the UN important efforts to promote global sustainable development in the chronological order since UN Conference on Human Environment in 1972, and ana- lyzes the progress and gap. The results show that the UN system has made great efforts for global sustainable development since the UN Conference on Human Environment, especially since UN Conference on Environment and Development, promoted the for- mation of important consensus and multilateral internhtional con- ventions on many fields, boosted the development of partnership in the field of sustainable development, and accelerated actions for sustainable development of many countries and regions. However, at present, the progress made is still far below the level required, prominently reflected in the slow progress toward the millen-nium development goals, the difficulties in negotiations in the field of environment and development, insufficient fulfillment of international agreements and conventions, and undesirable effects of partnership in the field of sustainable development. Based on these, the paper puts forward four suggestions for UN Conference on Sustainable Development in 2012（Rio＋20）： （1） to revitalize the ＂spirit of Rio＂ and accelerate the implementation of existing politi- cal commitments; （2） to make new political commitments focusing on climate change and other major global challenges under the Rio principles; （3） to lay out a blueprint of green economy under the Rio principles; and （4） to promote South-South cooperation as the focus of international cooperation.

Carbon Productivity Analysis to Address Global Climate Change

Developing low-carbon economy and enhancing carbon productivity are basic approaches to coordinating economic development and protecting global environment, which are also the major ways to address climate change under the framework of sustainable development. In this paper, the authors analyze the annual rate of carbon productivity growth, the differences of carbon productivity of different countries, and the factors for enhancing carbon productivity. Consequently, the authors clarify their viewpoint that the annual rate of carbon productivity growth can be used to weigh the efforts that a country takes to address climate change, and propose policies and suggestions on promoting carbon production.

Marine Renewable Energy Seascape

Energy production based on fossil fuel reserves is largely responsible for carbon emissions, and hence global warming. The planet needs concerted action to reduce fossil fuel usage and to implement carbon mitigation measures. Ocean energy has huge potential, but there are major interdisciplinary problems to be overcome regarding technology, cost reduction, investment, environmental impact, governance, and so forth. This article briefly reviews ocean energy production from offshore wind, tidal stream, ocean current, tidal range, wave, thermal, salinity gradients, and biomass sources. Future areas of research and development are outlined that could make exploitation of the marine renewable energy （MRE） seascape a viable proposition; these areas include energy storage, advanced materials, robotics, and informatics. The article concludes with a sustainability perspective on the MRE seascape encompassing ethics, leg- islation, the regulatory environment, governance and consenting, economic, social, and environmental constraints. A new generation of engineers is needed with the ingenuity and spirit of adventure to meet the global challenge posed by MRE.

ATTACKS AND IMPROVEMENTS ON THE RFID AUTHENTICATION PROTOCOLS BASED ON MATRIX

Most of the Radio Frequency IDentification (RFID) authentication protocols, proposed to preserve security and privacy, are analysed to show that they can not provide security against some passive or active attacks. In this paper, the security of two matrix-based protocols, proposed by Karthikeyan and Nesterenko (KN protocol) and Ramachandra et al. (RRS protocol) that conform to Electronic Product Code Class-1 Generation-2 (EPC Class-1 Gen-2) standard, are investigated. Using the linear relationship of multiplication of matrix and vector, we point out that both protocols can not provide scalability, and they are vulnerable to passive impersonation attack. In addition, both protocols are totally insecure if the adversary can compromise one tag to extract the secrets. A modified lightweight matrix-based authentication protocol is presented, which can resist mainly common attacks on an RFID authentication system including eavesdropping, relay attack, desynchronization attack, impersonation attack and tag tracking attack. The new protocol also has the desirable scalability property and can keep secure under compromising attack.

Building Taiwan Aeropolis of Airports through Infrastructuring Care and Integrity

Global changes, including the rise of the sea level and frequent terrible disasters, are apparently threatening the living environment. For environmental mitigation, security, and sustainability, Taiwan should have reliable, incorporative area-based security-information networks to protect their environments. Plural （dual） surveillance which is rooted in biologic senses, e.g., from two-eyes, can have the feature of fault-tolerance, availability and maintainability in monitoring tasks. Further, it can fit the contemporary wireless communication methods being incorporated with MIMO （multi-in multi-out）, to prevent information loss, interference, unexpected changes caused by such as clogged water and chemical reactions. Consequently, network prototypes, including SW （spider-web）network and CCC （cube-connected cycle）, are proactively suggested. More reliable capabilities, including those encouraging local ferries and drones, for efficient logistic operation and mixed-use buildings with quality assured performance, can be good for smart urban growth, resource utilization in Taiwan, which is aimed as an aerotropolis--a means for placemaking.

Social Networks Among Migrants in Saudi Arabia （SA）： Opportunities and Implications

This paper presents results of a pilot research conducted among social networks of both Sudanese and Egyptians in Jeddah city, Saudi Arabia （SA）. The main objectives of the research are focused into four interrelated issues： （1） to analyse the structural-function of the social networks of Sudanese and Egyptian migrants; （2） to explain the opportunities and challenges confronting the social networks; （3） to examine the elements of implications on SA society as perceived by the networks; and （4） to identify perceived future visions of the social network members in the context of their social and economic remittances in both countries. The research has applied a qualitative method and a structured interview sheet was used for data collection. The Sudanese sample focused on members from a Nubian social network in ]eddah who resemble skilled, semi-skilled, and unskilled labours, while the Egyptian sample selected randomly from semi-skilled youth labours and unskilled labours as informal groups. The research has found some differences in the structural functions of both groups. There are many similarities shared between the two groups in relation to conserving social ties, support and cooperation as one homogeneous socio-ethnic groups in the hosting country. Also, the results show that both groups follow similar strategies of social and economic remittances to home land. Moreover, both groups are suffering and facing many shared challenges regarding economic security and sustainability in the hosting country. While, the Sudanese group has clear vision in respect of the betterment of the migrants in SA, the Egyptian group perceives the future as gloomy and uncertain.

Natural Resources in Economies＇ Status Transition from ＇Periphery＇ to ＇Center ＇

This paper divides the history of global trade since 1000AD into three periods using Rahl Prebisch＇s center-periphery pattern and summarizes the effects of resource trade on periphery economies during each period. However, this paper argues that the resource curse paradox does not justify isolation between developing and developed countries. On the contrary, developing countries should be encouraged to integrate into the existing center-periphery pattern and achieve economic growth through resource trade. This paper supplements the existing literature＇s analysis of resource endowment＇s role in global trade and offers recommendations for resource-rich developing countries to avoid the resource curse, identify a viable path to development, and achieve sustainable development by harnessing natural resources more productively.

Scalable Arbitrated Quantum Signature of Classical Messages with Multi-Signers

Unconditionally secure signature is an important part of quantum cryptography. Usually, a signature scheme only provides an environment for a single signer. Nevertheless, in real applications, many signers may collaboratively send a message to the verifier and convince the verifier that the message is actually transmitted by them. In this paper, we give a scalable arbitrated signature protocol of classical proved to be secure even with a compromised arbitrator. messages with multi-signers. Its security is analyzed and proved to be secure even with a compromised arbitrator.

Global Environmental Change and National Security of China

The concept of security has been redefined since the 1990s. As one of the important factors threatening human security, global environmental change has become a new challenge to the national security and social development. The national security problems caused by global environmental change, on one hand, are closely related to the global environmental problems, and, on the other hand, are manifested in the conflicts of international affairs. The global environmental change severely challenges the future development of China. When it comes to the study on human dimensions of global environmental change in China, much more attention should be paid to issues of important environmental change that may have great impacts on the national security of China, to the scientific assessment of the vulnerabilities of the natural and socialeconomic system of China to the impacts of global environmental change, and to the active establishment of the national risk management system, in which global environmental change should be included, so as to make contribution to sustainable development and construction of harmonious society of China.

Methodology for Precious Metal Recovery in Computer Printed Circuit

The life of electronic equipment is becoming increasingly shorter and its replacement always generates a quantity of waste increase, giving rise to a problem of environmental character and still needed new options of solid waste management that will contribute to global sustainable development. Parts of these waste are TCI （the card＇s printed circuit） which containing dangerous elements and turns them into a polluting material from the soil, water and air, being harmful to human health if there is to proper and responsible way, so the recycling of TCI to obtain precious metals is an example of industrial materials that can be recycled. Despite this, large quantities of these are not recycled and some others are not considered. The objective of this work is to present a systematic and ecological methodology for the recovery of valuable materials contained in parts of used in computers, circuit boards using a leaching process. The method determines a set of variables to evaluate the kinetics of the reaction and the leaching of metals that form the substrate of metal and to establish the parameters that affect the rate of leaching of metals through a sensitivity analysis, to identify design alternatives. It determines the quantity and percentages that constitutes the motherboard, processor, video cards, accelerator graphics, network and memory cards RAM, among others and its content of metals such as Cu, Fe, Ag, Au and Pt.

Overview of Abandoned Mines in the Limpopo Province, South Africa： Rehabilitation Challenges

South Africa is facing enormous financial, environmental and social challenges posed by abandoned mines. This investigation focused on field verification of 850 abandoned mines and associated rehabilitation challenges in the Limpopo Province. The investigations included desktop studies, standardised field-based ranking system and sampling. The waste material samples were analysed using XRF （X-ray fluorescence spectrometry） at the Council for Geoscience Laboratory. Approximately 5% of 850 abandoned mines in the Limpopo Province require urgent rehabilitation either due to high concentrations of metals from mine dumps or presence of open shafts. For example, copper concentrations at Messina and Spoedwel were 9,719 ppm and 56,160 ppm, respectively. Birthday Gold Mine in Giyani area is characterised by un-safe open shafts and un-stable grounds which poses safety problems and limits the future land-use. Although these investigations have been conducted, it is not possible to rehabilitate all abandoned mines mainly due to limited financial resources. The abandoned mines close to human settlement are given priority due to their immediate threat to people. This study recommends that rehabilitation of abandoned mines should take cognisance of the sustainable future land use that will favour the creation of jobs and nature conservation.

Spatial-temporal Evolution Pattern of Agricultural Productivity in Northwestern Sichuan Plateau

Currently, the agricultural growth in developed countries mainly relies on the improvement of productivity, which is also the target for China. Accordingly, the purpose of this study was to describe the spatial-temporal evolution pattern of agricultural productivity, to reveal changes in total factor productivity in 2ooo-2olo, and analyze the impact of these changes in northwestern Sichuan plateau, China. Using data envelopment analysis （DEA） and the Malmquist Index, an in-depth study was conducted on agricultural productivity and changes in total factor productivity of 31 counties in northwestern Sichuan plateau. Results indicated that： （1） geographically, counties with optimal efficiency were mainly located in the north of northwestern Sichuan plateau and those with the lowest efficiency, in the south; （2） relative to pure technical efficiency, scale efficiency was the dominant factor in determining agricultural productivity; （3） the redundancy rate of input factors in zolo was slightly lower than that in zooo, thereby indicating an improved utilization of input factors to a certain extent and a great potential for further improving such utilization; （4） during the 2ooo-2olo period, the agricultural total factor productivity had an average annual growth rate of 8.3%, but the growth rates in various regions differed widely; （5） technical progress was the dominant factor promoting the improvement of total factor oroductivitv inagriculture. The disparities in spatial distribution may be due to the differences of natural conditions, former level agricultural productivity between counties. The findings are valuable for the government to make sustainable development policies for agriculture and improving agricultural development in northwestern Sichuan plateau.

Conceptual Framework for an Integrated Method to Optimize Sustainability of Engineering Systems

It is necessary to change the current dynamic of growth, to assure that future generations can satisfy their needs. Sustainable development and global sustainability are two concepts that have achieved great importance in almost every sector of activity. There is a wide range of methods and models for sustainability assessment. Nevertheless, it is necessary to go beyond evaluation, looking for sustainability optimization. In spite of this, little work has been done on the latter field. The authors present here a conceptual proposal for an integrated method to optimize sustainability of engineering systems, based on the MIVES （integrated value method for evaluating sustainability） method. For a better understanding of the method, its essential steps for optimizing an energy sub-system are summarized （shell-and-tube heat exchanger）.

Addressing the trade-climate change-energy nexus: China's explorations in a global governance landscape

We have arrived at a critical juncture when it comes to understanding the numerous ways in which trade interacts with climate change and energy(trade-climate-energy nexus).Trade remains crucial for the sustainable development of the world's greatest trading nation:China.After clarifying the linkages within the trade,climate change and energy nexus,this article delves into China's specific needs and interests related to trade,climate change and energy.Then it explores the ways in which trade can contribute to China's needs,to sustainable energy development and to the goals of the global climate agreement that is under negotiation.One main findings are China is a key participant in negotiations on trade liberalization of environmental technologies and services.These negotiations are in China's interests in terms of innovative industries,technological upgrading,employment and public health.China could stand up for the interests of other emerging and developing countries and serve as an example in terms of transitioning to a low-carbon economy.Beyond trade barriers issues of domestic(energy)regulation such as fossil-fuel subsidies as well as investment,competition-policy,tradefacilitation and transit issues related to clean energy need to be addressed.Building trust between relevant actors across sectors and national borders will be of the essence in order to foster long-term cooperation on technological innovation.As a way forward,different approaches towards the governance of trade and climate change will be highlighted.Besides discussing the specific aspects of Chinese participation in global trade and climate change governance,this paper aims at offering broader insights into the nexus between trade,energy and climate governance in China.

Stumbling Blocks in Cloud Computing Adoption Pathway： A Charter

Cloud computing is currently an embryonic domain in the area of information technology that possesses the power of transforming the way information technology （IT） services are delivered and maintained in the business world. Pay as per the usage kind of cost structure coupled with delivery of computing services through internet makes cloud computing an exciting and potential growth oriented information technology model compared with conventional computing services delivery models. Various additional features like scalability, flexibility and easy deployment process creates a window for the organizations even relatively smaller in size to get benefitted by the highly advanced ＆ modern technologies without incurring substantial cost. In spite of so many benefits of this new delivery model, concerns are beginning to grow about how safe an environment it is. Despite of all the hype surrounding the cloud, enterprise customers are still reluctant to deploy their business in the cloud. Security is one of the major issues which reduces the growth of cloud computing and complications with data privacy and data protection continue to plague the market. Other related concerns associated with the adoption of cloud computing include trust on service providers, loss of control and compliance issues. This paper is an attempt to explore security ＆ trust issues linked with cloud computing adoption in the Small and Medium Enterprises （SME） sector.