分组传送网技术在智能电网电力通信中的应用

随着信息技术的高速发展,人类通信已进入3G时代。为实现十二五规划战略目标,我国逐步开始进行智能电网构建工程。由于传统的电力通信网已不能满足电力通信网接入需求,国家电网公司在十二五期间将要建设特高压工程,本文结合我国电力通信的实际需求和发展,简述了分组传送网技术(packet transport network,PTN)的发展应用和趋势。以实现电网可靠、安全、经济、高效、环境友好和使用安全的目标。

Understanding biological functions through molecular networks

The completion of genome sequences and subsequent high-throughput mapping of molecular networks have allowed us to study biology from the network perspective. Experimental, statistical and mathematical modeling approaches have been employed to study the structure, function and dynamics of molecular networks, and begin to reveal important links of various network properties to the functions of the biological systems. In agreement with these functional links, evolutionary selection of a network is apparently based on the function, rather than directly on the structure of the network. Dynamic modularity is one of the prominent features of molecular networks. Taking advantage of such a feature may simplify network-based biological studies through construction of process-specific modular networks and provide functional and mechanistic insights linking genotypic variations to complex traits or diseases, which is likely to be a key approach in the next wave of understanding complex human diseases. With the development of ready-to-use network analysis and modeling tools the networks approaches will be infused into everyday biological research in the near future.

TCAR: A new network coding-aware routing mechanism based on local topology detection

Recent researches show that inter-session network coding could decrease the number of packets transmission and achieve higher throughput in wireless network compared with traditional forwarding mechanism. In most existing relay mechanisms based on inter-session network such as COPE, relay node demands to collect the messages from its neighbor nodes to get notice of which packets already overheard by them so as to determine whether there exists coding opportunity between or among forwarding packets. However, transmission overhead of this message collection and computing cost of opportunity determination will degrade the performance of these mechanisms. It is observed that coding opportunity at relay node is much more related with the local topology, and the opportunity of encoding three or more packets together is far less than that of encoding two packets together in wireless network with general density. Based on this, a new coding-aware routing mechanism, named TCAR, is proposed. TCAR ignores the oppommity of encoding three or more than three packets together. Each relay node maintains an encoding mapping table being established according to the result of its local topology detection, which can be used to calculate the path cost during routing setup phase, and determine that which two packets can be encoded together during the packets forwarding phase. In TCAR, instead of periodic messages collection, each relay nodes just need once local topology detection, and the encoding determination is much simpler than that of the former mechanisms. Simulation results show that compared with typical inter-session network coding mechanisms COPE and COPE-based routing, TCAR achieves 12% and 7% throughput gains, and keeps the minimum end to end delay.

Efficient Broadcast Retransmission Based on Network Coding for InterPlaNetary Internet

In traditional wireless broadcast networks,a corrupted packet must be retransmitted even if it has been lost by only one receiver.Obviously,this is not bandwidth-efficient for the receivers that already hold the retransmitted packet.Therefore,it is important to develop a method to realise efficient broadcast transmission.Network coding is a promising technique in this scenario.However,none of the proposed schemes achieves both high transmission efficiency and low computational complexity simultaneously so far.To address this problem,a novel Efficient Opportunistic Network Coding Retransmission(EONCR)scheme is proposed in this paper.This scheme employs a new packet scheduling algorithm which uses a Packet Distribution Matrix(PDM)directly to select the coded packets.The analysis and simulation results indicate that transmission efficiency of EONCR is over 0.1,more than the schemes proposed previously in some simulation conditions,and the computational overhead is reduced substantially.Hence,it has great application prospects in wireless broadcast networks,especially energyand bandwidth-limited systems such as satellite broadcast systems and Planetary Networks(PNs).

Combination advertising with budget constraint

An appropriate advertising mode selection and allocation of advertising budgets considering advertising budget constraints are developed with the game theory and optimization model.The results show that the advertising budget and the weakening factor of the online advertising effects on the traditional advertising affect sellers advertising,pricing strategies and budget allocation.The effectiveness of combination advertising is a Pareto optimum relative to the traditional advertising in a certain range.The weakening effect of the online advertising on the traditional advertising has a nonlinear effect on the advertising strategy and pricing strategy.In addition,sellers choose combination advertising with different budget constraints,and there is an optimal budget allocation ratio.In certain cases,sellers can obtain an optimal advertising expenditure less than the budget constrain.When sellers adopt combination advertising with enough budget,they do not invest in traditional advertising without limit.Moreover,compared with enough budget,when sellers adopt combination advertising with budget constrain,sellers do not decrease the advertising allocation of online advertising since online advertising is more efficient.

Study on the network delay of periodic information in the NCS based on EPA

The network delay of the periodic messages transmission in the network control system （NCS） based on Ethemet for plant automation （EPA） is analyzed from the theoretical and experimental perspective in this paper. The composition and the characteristics of the network delay of EPA periodic messages transmission in a subnet is studied through analyzing the information transmission regularity and EPA deterministic scheduling mechanism. On this basis, the queuing delay at communication schedule management entity （EPA _ CSME） that is the most important component of network delay is analyzed, during which the formulas for the queuing delay of periodic messages and other real time parameters are proposed. Furthermore, an experiment is developed to test each component of network delay of periodic messages transmission in a EPA subnet. According to the experimental and the theoretical analysis, the conclusion is drawn that the delay during which the periodic messages wait for the periodic messages transmission time slice is the main factor that causes considerable network delay, and improvement method is presented.