Towards a portable environment for FORTRAN applications on parallel computers

Summary This paper extends the communicating sequential process model of communications on multicomputers to a virtual machine interface with skeleton algorithms for global communication of data. The software is constructed using elements of object-oriented programming. Data is divided into two types of variables: those stored locally to each process and those accessible globally. Transfer of data between processes is implicit in the library structure, providing opportunities for optimisation.The application-level interface currently resembles a vector linear algebra library. Generic communication skeletons are defined for building libraries specific to applications; they illustrate more general programming issues. An example from a wave-scattering algorithm is given.     

Identification and synthesis of new bicyclic acetals from caddisflies (Trichoptera)

As shown by synthesis and enantioselective gas chromatography, males and females of the caddisfly species Potamophylax latipennis and Potamophylax cingulatus produce (1R,3S,5S,7S)-1-ethyl-3,5,7-trimethyl-2,8-dioxabicyclo[3.2.1]octane, while Glyphotaelius pellucidus produces 1,3-diethyl-4,6-dimethyl-2,7-dioxabicyclo[2.2.1]heptane, having either the (1S,3S,4R,6S) or (1R,3R,4S,6S)-configuration. As shown by electrophysiological investigations, the compounds are perceived by the antennae of both sexes.     

基于FPGA的跳频通信系统开发

为了提高通信的抗干扰和保密性,对跳频通信进行了研究,通过分析跳频通信的实现方式,提出基于FPGA的跳频通信系统实现方案。该方案中发端信号采用QPSK调制,接收端采用超外差接收以达到减少噪声和提高接收灵敏度的效果,接收端跳频同步采用等待自同步的跳频捕获和基于延迟锁相环的跳频跟踪。测试结果表明所设计的跳频通信系统可以正确实现跳频通信。与传统跳频通信实现方案相比,该方案具有灵活性强、开发周期短、开发费用低等优点。     

Consistency and the graph Banzhaf value for communication graph games

The graph Banzhaf value was introduced and axiomatically characterized by Alonso-Meijide and Fiestras-Janeiro (2006). In this paper we propose the reduced game and consistency of the graph Banzhaf value for communication situations. By establishing the relationship between the Harsanyi dividends of a coalition in a communication situation and the reduced communication situation, we provide a new axiomatization of the graph Banzhaf value by means of the axioms of consistency and standardness.     

Joint trajectory and communications design for high air-interface-resource efficiency

Applying aerial devices to collect data from terrestrial sensors is a research hotspot in recent years. In this paper, we consider a novel system model that terrestrial sensors’ data are first collected by low-altitude UAVs and then transferred to a relatively-high-altitude central processor. We formulate the model in such an air-ground integrated system as a non-convex optimization problem of maximizing the air-interface-resource efficiency (AIRE) by jointly optimizing the trajectories and communication schedules. By using techniques of block coordinate descent (BCD) and successive convex approximation (SCA), the proposed problem is relaxed and transformed into three subproblems, which can be solved by iteration. Simulation results show the optimized trajectories and communication schedules, and the designed schemes perform better than the benchmarks.     

Fundamental energetic limits of radio communication systems

The evaluation of the energy consumption of a radiocommunication requires to analyse the life cycle of the elements used. However, this analysis does not specify the energetic limits. Theoretical approaches allow one to draw these limits, which are known in multiple cases of information transmission. However, the answers are not always satisfactory, in particular in the case of time-varying channels. After a brief presentation of the notion of energetic limits of a radiocommunication, and beginning with a global approach, we show that, contrary to the published results, the energetic limits always differ from zero if the physical constraints are correctly expressed.     

Logic and logicians in Russia before 1917: Living in a wider world

We explore the formation of Logic as an academic discipline and community in Russia before the revolution of 1917. In particular, we look at the various communication strategies that emerged within this community and its relations with the wider international scientific community. Interaction with Mathematics, which was undergoing its own “foundational revolution,” played a major role in the transition from archaic syllogistic to modern formal logic. We make extensive use of original sources, many of which have not been reprinted since their first publication.     

Position-specific information in social networks: Are you connected?

Individuals in social networks often imperfectly monitor others’ network relationships and have incomplete information about the value of forming new relationships. This paper introduces the Generalized Conjectural Equilibrium (GCE) concept for such settings and completely characterizes the set of GCE networks when players observe only local parts of the network. Incomplete information and imperfect monitoring generate different types of inefficiency. These inefficiencies increase in number and scope as network observation becomes more localized. These results suggest that actual social networks will be structured inefficiently in general.     

大气信道紫外光通信系统通信距离的增程方法

介绍了紫外光大气传输理论和非直视单散射模型.在此模型基础上,针对紫外光通信系统的结构设计对信道能量损耗的影响进行了理论上的定性分析.对不同天气、不同通信模式、不同几何结构参量条件下,大气信道所产生的能量损耗进行了定量仿真.仿真结果表明:能量衰减随通信距离的增加而增大;不同能见度条件下,能量衰减随通信距离的递增程度不同,能见度越高能量衰减越小,可实现的通信距离越远;通信距离随发射仰角的减小而增加,随接收仰角的减小而增加,且发射仰角对通信距离的影响程度大于接收仰角;通信距离随发射束散角的增加而增加,随接收视场角的减小而增加,且接收视场角对通信距离的影响程度远大于发射束散角.