Traffic characterization algorithms for VBR video in multimedia networks

A network that offers deterministic, i.e., worst case, quality-of-service guarantees to variable-bit-rate (VBR) video must provide a resource reservation mechanism that allocates bandwidth, buffer space, and other resources for each video stream. Such a resource reservation scheme must be carefully designed, otherwise network resources are wasted. A key component for the design of a resource reservation scheme is the traffic characterization method that specifies the traffic arrivals on a video stream. The traffic characterization should accurately describe the actual arrivals, so that a large number of streams can be supported; but it must also map directly into efficient traffic-policing mechanisms that monitor arrivals on each stream. In this study, we present a fast and accurate traffic characterization method for stored VBR video in networks with a deterministic service. We use this approximation to obtain a traffic characterization that can be efficiently policed by a small number of leaky buckets. We present a case study where we apply our characterization method to networks that employ a dynamic resource reservation scheme with renegotiation. We use traces from a set of 25–30-min MPEG sequences to evaluate our method against other characterization schemes from the literature.     

基于受限广播搜索的分布式QoS组播路由协议

根据像网络电视这样的宽带多媒体业务的需要，提出了一种简单有效的分布式QoS组播路由协议来支持动态成员组播。分析和仿真表明，本协议和其它同类协议比具有消息开销少、成功率高、路径建立时延短和性能稳定等优点。     

VEGF and FGF2 Improve Revascularization,Survival, and Oocyte Quality of Cryopreserved,Subcutaneously-Transplanted Mouse Ovarian Tissues

This study was conducted to investigate the effect of the vascular endothelial growth factor (VEGF) and fibroblast growth factor 2 (FGF2) on revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue. Autologous subcutaneous transplantation of vitrified-thawed mouse ovarian tissues treated with (experimental group) or without (control group) VEGF and FGF2 was performed. After transplantation to the inguinal region for two or three weeks, graft survival, angiogenesis, follicle development, and oocyte quality were examined after gonadotropin administration. VEGF coupled with FGF2 (VEGF/FGF2) promoted revascularization and significantly increased the survival rate of subcutaneously-transplanted cryopreserved ovarian tissues compared with untreated controls. The two growth factors did not show long-term effects on the ovarian grafts. In contrast to the untreated ovarian grafts, active folliculogenesis was revealed as the number of follicles at various stages and of mature oocytes in antral follicles after gonadotropin administration were remarkably higher in the VEGF/FGF2-treated groups. Although the fertilization rate was similar between the VEGF/FGF2 and control groups, the oocyte quality was much better in the VEGF/FGF2-treated grafts as demonstrated by the higher ratio of blastocyst development. Introducing angiogenic factors, such as VEGF and FGF2, may be a promising strategy to improve revascularization, survival, and oocyte quality of cryopreserved, subcutaneously-transplanted mouse ovarian tissue.     

An elementary approach to optimal discrete-time search strategies

Optimal strategies are known for the finite and infinite horizon discrete-time search with constant unit cost and without recall. These strategies were obtained in the theory of optimal stopping, based on the martingale convergence theorem and other tools from probability theory. We present here an elementary approach to these problems, relying only on routine calculation of expected values. In the finite horizon case, the solution utilizes a simple form of backward induction, in conjunction with a nonlinear dynamical system, to compute the parameters of the optimal strategy. An elementary proof is also given that a simple threshold search is optimal among all strategies with finite expected total cost.     

Predictive economic efficiency of combining nuclear power plants with autonomous hydrogen power complex

Currently, the United Energy System (UEC) of Russia is trending in the deficit of peak and half-peak capacity with a simultaneous increase in the number of nuclear power plants (NPPs), which will require the participation of the NPPs in the variable part of the schedule of electrical loads.In addition to the economic need to maintain the high-level utilization rate, there are technological limitations of maneuverability for NPPs.The authors developed an approach to solving this problem by combining with an environmentally friendly energy source – an autonomous hydrogen power complex, which includes thermal batteries and an additional multifunctional low-power steam turbine installation.The developed energy complex can also provide reliable reservation of electricity supply to consumers of their own needs of the nuclear power plant in case of complete blackout of the plant.The feasibility study of the main equipment of the autonomous hydrogen power complex, which is necessary for combining with a two-unit nuclear power plant with WWER-1000, has been evaluated.On the basis of the assessment of the inflation indicators of the Russian economy over the past 11 years, three variants of fuel cost dynamics and tariff rates for electricity (capacity) as well as the size of operating costs, including depreciation deductions to the main equipment, are defined, taking into account the current principles of price formation.The result is a value for accumulated net present value, depending on the ratio of the cost of the half-peak and off-peak electricity at different inflation rates.The positive economic effect of reducing the risk of the core damage accident, replacing the construction of the gas turbine unit as a maneuverable source of electricity in the power grid and increasing the income of the Russian federal budget from the savings of natural gas has been taken into account.The greatest economic efficiency is achieved with maximum projected inflation, which is associated with the maximum rate of discounting and the high rate of growth of electricity tariffs.Reducing the risk of the core damage accident ensures that the proposed approach is competitive in all the inflation options under consideration and the ratio of electricity tariffs.     

厚松散层薄基岩条带法开采采留尺度研究

基于建筑物下条带法开采的地表变形观测，结合数值模拟方法，研究了厚松散层薄基岩条件下，条带法开采不同采留尺度的地表沉陷规律.研究表明，按一般条带法设计进行的地表沉陷预测下沉系数较实际偏小；且相同条带采出宽度时基岩厚度小，地表下沉值增大；相同基岩厚度时条带采出宽度小，地表下沉值也小；基岩厚度较小时，地表下沉值随条带采宽增大时增加较大；进行条带开采采留尺度设计时，除了按一般情况下的设计原则考虑外，还应考虑基岩的厚度，使得开采后支托层在基岩内形成，以保证条带开采控制地表沉陷的意义.     

河北省耕地资源动态分析及耕地后备资源可持续利用对策

本文分析了河北省土地资源的利用现状以及自实施耕地总量动态平衡制度以来耕地数量和类型的动态变化,并提出了遏制耕地锐减的对策,其中对耕地后备资源科学合理的开发是有效举措之一.8年间河北省耕地面积减少了50.75×104 hm2,生态退耕还林面积占耕地减少面积的89.0%,土地开发是新增耕地的主要来源;可开垦荒草地、可开垦滩涂、可开垦盐碱地是新增耕地的主要开发对象,占耕地后备资源面积的78.86%.     

河北省耕地资源动态分析及耕地后备资源可持续利用对策

本文分析了河北省土地资源的利用现状以及自实施耕地总量动态平衡制度以来耕地数量和类型的动态变化,并提出了遏制耕地锐减的对策,其中对耕地后备资源科学合理的开发是有效举措之一。8年间河北省耕地面积减少了50.75×104hm2,生态退耕还林面积占耕地减少面积的89.0%,土地开发是新增耕地的主要来源;可开垦荒草地、可开垦滩涂、可开垦盐碱地是新增耕地的主要开发对象,占耕地后备资源面积的78.86%。     

Priority-Based Routing Resource Assignment Considering Crosstalk

Crosstalk has become one of the most critical concerns in very deep sub-micron era. This paper deals with the problem of crosstalk mitigation at both methodological and algorithmic levels. Noting that intermediate operations between global routing and detailed routing are very effective in crosstalk estimation and reduction, the authors propose to incorporate several intermediate steps that are separated in traditional design flow into an integrated routing resource assignment stage, so that the operations could easily cooperate to fully exert their power on crosstalk reduction. An efficient priority-based heuristic algorithm is developed, which works slice by slice. Crosstalk avoidance, and many other aspects that are critical in routing practice including congestion, vias, layer preference, etc., are taken into account. A track reservation strategy is adopted in the algorithm framework to compensate the undesired effects caused by sequential routing. Experimental results on a series of ISPD98 and industrial benchmarks show that the proposed approach is able to reduce capacitive crosstalk by about 70% on average without compromising completion ratio compared with a previously reported graph based algorithm, demonstrating the advantages of the approach.     

服务元网络体系结构下的QoS机制研究

服务元网络体系结构采用改进树型网络拓扑结构，统一对数据类型进行划分，使用QoS区域路由方式转发数据，通过通信量整形彻底解决拥塞问题。本文着重分析介绍了服务元网络体系结构中上述QoS机制的基本原理和工作机制，并将其与现有TCP／IP网络对应机制进行了比较，得出了服务元网络体系结构的QoS机制更能满足当今分布式多媒体应用需求的结论。