Security Concerns in IPv6 and Transition Networks

ABSTRACT

This whitepaper introduces the concept of a transitional network, defines what it is, how it is used and why a transitional network is necessary. A brief history of IPv6 is given followed by a review of the known vulnerabilities associated with the IPv6 protocol. Popular transition strategies are explored in greater detail around issues of cost, implementation and security vulnerabilities. Mitigation techniques and counter-measures are reviewed against known exploits for each of the transition mechanisms. The last section offers an in depth investigation into the IPv6 mobility protocol, Network Address Translation - Protocol Translation (NAT-PT) and tunneling options.     

Scenario relaxation algorithm for finite scenario-based min–max regret and min–max relative regret robust optimization

Most practical decision-making problems are compounded in difficulty by the degree of uncertainty and ambiguity surrounding the key model parameters. Decision makers may be confronted with problems in which no sufficient historical information is available to make estimates of the probability distributions for uncertain parameter values. In these situations, decision makers are not able to search for the long-term decision setting with the best long-run average performance. Instead, decision makers are searching for the robust long-term decision setting that performs relatively well across all possible realizations of uncertainty without attempting to assign an assumed probability distribution to any ambiguous parameter. In this paper, we propose an iterative algorithm for solving min–max regret and min–max relative regret robust optimization problems for two-stage decision-making under uncertainty (ambiguity) where the structure of the first-stage problem is a mixed integer (binary) linear programming model and the structure of the second-stage problem is a linear programming model. The algorithm guarantees termination at an optimal robust solution, if one exists. A number of applications of the proposed algorithm are demonstrated. All results illustrate good performance of the proposed algorithm.     

VRML虚拟场景跳转及三维造型交互

VRML构造复杂三维场景时,通常需要多个场景的组合。如何实现三维空间场景跳转和三维造型的动态效果十分关键？结合实例讨论并给出利用Anchor组节点实现多场景跳转的方法,在动态三维造型的基础上利用传感器Sensor节点,实现复杂的交互功能：     

Generating generic response signals for scenario calculation of management effects on carbon sequestration in agriculture: approximation of main effects using CENTURY

In this study, a well bounded and validated biogeochemical model, CENTURY, is used to mimic behaviour of soil carbon under different agricultural management regimes in Australian conditions to provide simple soil carbon response signals for use in a multi-criteria, spatial framework for analysis of management effects on carbon storage. The study is concerned with relative change in soil carbon resulting from change in management, and not concerned with absolute values either of change or final stock. Simulations were run for a range of starting soil carbon levels, soil physical properties, and climate sites using two carbon pool allocations within the model. A simplified set of agricultural land management options was used consisting of warm season native grassland, warm/cool season mixed native grassland, improved pasture, continuous wheat, conservation tillage, and long and short cereal rotations with lucerne. There were large differences in simulation results between crop and pasture systems and management types within systems. Within management types, starting soil carbon levels had the major influence on simulation outcomes. The derived carbon response signals for agricultural management practices, summarised over soils and climate, tended to underestimate losses under cropping and overestimate gains from perennial grassland when compared to field data. The value of these signals in a scenario analysis is discussed.     

Study of acrylamide mitigation in model system: Effect of pure phenolic compounds

Many natural antioxidant extracts were reported to potentially reduce the acrylamide formation during Maillard reaction. In this work, the effect of pure antioxidant molecules on acrylamide net amount was investigated in an equimolar asparagine–glucose system (10 mM) during heating (200 °C). All experimentations were performed in the newly designed test cell. Cinnamic acid and six phenolic compounds (gallic, ferulic, coumaric, caffeic acids, catechin, and epicatechin), displaying different antioxidant capacity, were added at 5 mM to the model system. The results indicated no reduction effect of the tested compounds on acrylamide net amount. Moreover, in the case of ferulic acid a slight but significant promoting effect was observed. An increase of antioxidant activity was also noticed during heating of model solution spiked with caffeic acid but the acrylamide level was not affected.     

Cost Analysis of Soil Depressurization Techniques for Indoor Radon Reduction

A parametric cost analysis was conducted to determine the importance of various system design and operating variables on t h installation and operating costs of active soil depressurization (ASD) systems for indoor radon reduction in houses. The objective was to help guide the research and development (R&D) efforts of the US. Environmental Protection Agency (EPA) to reduce ASD costs. Annual lung canter deaths due to radon cannot be reduced by more than about 14% to 22% unless houses having pre-mitigation levels of 148 Bqlm³ and less receive radon reduction systems. Reductions in ASD costs might increase voluntary use of this technology by homeowners at those levels. The analysis showed that various modifications to ASD system designs offer potential for reducing installation costs by up to several hundred dollars ¹ 1 All costs are expressed in U.S. dollars.
, but would not reduce total installed costs much below $800–$1000. Reductions of this magnitude would probably not be sufficient to dramatically increase voluntary use of ASD technology. Thus, some innovative, inexpensive mitigation approach other than ASD would appear to be necessary. Decreased ASD fan capacity and increased sealing might reduce ASD operation costs (for fan electricity and house heating/cooling) by roughly $7.50 per month. It is unlikely that this amount would be a deciding factor for most homeowners.     

Reducing the acrylamide content of a semi-finished biscuit on industrial scale

The baking agent, reducing sugars and organic acids are the ingredients that most influence the acrylamide formation in sweet bakery. Various experiments focusing on these components were performed with biscuits on industrial scale. The replacement of ammonium hydrogencarbonate by sodium hydrogencarbonate reduced the acrylamide content by about 70%. The use of a sucrose solution instead of inverted sugar syrup had a similar effect. Addition of some extra tartaric acid reduced the acrylamide content by about one-third. The positive effects on the acrylamide content were still observed after a second baking process. These results show that mitigation in industry-scale based on the optimization of baking agent, reducing sugars, and organic acid is feasible and compliant to high-quality standards.     

Environmental aspects of geothermal energy utilization

Geothermal energy is a clean and sustainable energy source, but its development still has some impact on the environment. The positive and negative aspects of this environmental impact have to be considered prior to any decision to develop a geothermal field, as well as possible mitigation measures. The main environmental effects of geothermal development are related to surface disturbances, the physical effects of fluid withdrawal, heat effects and discharge of chemicals. All these factors will affect the biological environment as well. As with all industrial activities, there are also some social and economic effects. In Iceland an enforcement program was launched in the early 1990s to study the environmental impact of developing geothermal resources. Work began on tackling the environmental issues relative to the high-temperature geothermal fields under development in Iceland. Research was conducted on microearthquake activity in geothermal areas and a methodology developed for mapping steam caps. The foundations were laid of networks for monitoring land elevation and gravity changes. Baseline values were defined for the concentrations of mercury and sulfur gases. Groundwater monitoring studies were enforced. Atmospheric dispersion and reaction of geothermally-emitted sulfur gases and mercury were studied. Aerial thermographic survey methods were refined and tested and their capacity to detect and map changes in surface manifestations with time was demonstrated. To further the use of geothermal energy worldwide the International Energy Association set up a Geothermal Implement Agreement (GIA) in 1997; its environmental Annex has been actively implemented, with several projects still under way.     

Scenario inspections

Scenarios help practitioners to better understand the requirements of a software system as well as its interface with the environment. However, despite their widespread use both by object-oriented development teams and human–computer interface designers, scenarios are being built in a very ad-hoc way. Departing from the requirements engineering viewpoint, this article shows how inspections help software developers to better manage the production of scenarios. We used Fagans inspections as the main paradigm in the design of our proposed process. The process was applied to case studies and data were collected regarding the types of problems as well as the effort to find them.

稳压器卸压阀卸压效果研究

基于国际上模拟严重事故瞬态过程最详细的机理性程序SCDAP/RELAP5/MOD3.1,主要分析研究了核电站未紧急停堆的预期瞬变(ATWS)初因(失去主给水、失去厂外电和控制棒失控提升)叠加辅助给水失效导致的堆芯熔化严重事故进程,并验证阻止ATWS导致堆芯熔化进程的一次侧卸压缓解措施的充分性和有效性.计算分析结果显示,一列稳压器卸压阀不足以充分降低一回路压力,压力仍然停留在10MPa以上,存在很大高压熔堆的风险.增加一列卸压阀可把一回路压力降低到3MPa左右,安注系统得以投入,及时有效地阻止堆芯熔化进程,降低了高压熔堆风险.分析结果还显示高压安注系统的投入对一回路卸压具有重要影响.