Underground Cooperative Spectrum Sensing Based on Neural Network

针对煤矿安全生产中无线通信的瓶颈问题，指出认知无线电中的单节点频谱感知不能适应井下的多径衰落和噪声等问题，提出把多节点合作感知应用到煤矿井下；煤矿井下的环境参数多变，结合具有适应能力强的神经网络，讨论基于神经网络的合作频谱感知模型设计思路，通过MATLAB仿真验证，检测性能优于AND，OR准则。     

Identifying the Core Periodical Literature of the Agricultural Communications Documentation Center

ABSTRACT

“Agricultural communications” is an emerging field which is naturally both part of the “agriculture” and “communications” literature. However, it is much broader than just a subset of each. The coverage of standard databases such as CAB Abstracts and Communication Abstracts, while a good start, does not sufficiently cover the field. The Agricultural Communications Documentation Center (ACDC) at the University of Illinois at Urbana-Champaign has, over the last quarter century, worked to help define and collect this literature, by identifying relevant documents and entering them into a Web-searchable Microsoft Access database. An analysis of this database reveals important clues concerning the literature of agricultural communications. Of the nearly 30,000 documents within the ACDC collection, periodical articles comprise a little over one half, from a core list of 45 periodicals within the ACDC collection. More than one half of these core periodicals are outside the traditional agriculture and life science literature; approximately one third are scholarly journals.     

Intercropping Combination and Information Sources Among Kola Farmers in Osun State,Nigeria

Appropriate planting patterns ensure sustained soil fertility and higher productivity for farmers. This study assessed the intercropping crop combinations and information sources of kola farmers in Osun State, Nigeria. Sixty respondents were selected using multistage and purposive random sampling techniques. Data were collected with a structured questionnaire. The arable crops commonly intercropped with kola were plantain/banana, yam, cassava, and maize. Tree crops combined with kola included cocoa, citrus, and oil palm. Co-farmers/friends and radio served as popular sources of information for farmers. Farm size was significantly related to respondents’ information sources on kola intercropping. The authors recommend that the Cocoa Research Institute of Nigeria's extension personnel make greater use of information sources most frequently used by respondents in order to ensure adequate cropping systems.     

Contribution of Farm-Radio Broadcasts to Yam Output in Benue State,Nigeria

This study analyzed farmers’ perceptions of the contribution of farm-radio broadcasts to yam production. Data collected from 200 randomly selected farmers in Benue State, Nigeria using a structured questionnaire showed that 94.0% considered hours of broadcasts (8 a.m., 11 a.m., 2:30 p.m., and 7 p.m.) suitable, 98.5% were satisfied with the language of broadcasts, 97.5% found the contents adequate, and 88.5% utilized the messages. The paired sample t test showed significant differences between yield of yams before and after listening to radio (p < .01), indicating farm-radio broadcasts’ contribution to productivity. It is recommended that farm-radio broadcasts be intensified and sustained to enhance output and food security.     

基于无线和短信环境安全型猪舍监控技术研究

通过无线和短信结合,实现了对环境安全型猪舍的监控。系统由无线智能传感器、无线或短信通信终端、监控中心和执行节点四部分组成,采用集散控制方法。监控中心是整个系统的核心,对数据进行集中管理、分析和处理,其他部分负责数据采集、传输和执行。     

Evaluation of Juvenile salmon passage and survival through a fish weir and other routes at Foster Dam,Oregon, USA

Downstream passage for juvenile Chinook salmon Oncorhynchus tshawytscha (Walbaum) and steelhead Oncorhynchus mykiss (Walbaum) through the fish weir at Foster Dam, Oregon, was evaluated to assess the weir's efficacy as a long-term passage solution. Radio telemetry was used to estimate survival, passage and effectiveness for the fish weir, spillway and turbines. Survival of Chinook salmon through the fish weir varied by season and reservoir elevation (66%–87%), and passage proportions were low (8%–20%). Fish weir effectiveness was low to moderate (0.39–2.09). Steelhead survival was lower (57%–77%) but passed the fish weir in higher proportions (77%), and weir effectiveness was consistently high (2.96–5.49). The results indicate the existing fish weir will not be a suitable long-term passage solution for all species. However, because of the high passage proportions and effectiveness observed for steelhead, further development of the surface-flow concept appears to be promising for safely passing downstream-migrating fishes.     

Habitat use,home range,movements and interactions of introduced Lepomis gibbosus and native Salmo trutta in a small stream of Southern England

Radio telemetry data were analysed to assess the microhabitat use, movement patterns, home range overlap and interspecific interactions of non‐native pumpkinseed Lepomis gibbosus (L.) and native brown trout Salmo trutta (L.) in a small English stream located immediately below a commercial angling lake from which pumpkinseed escaped. Although both species favoured pool habitats, brown trout preferred higher velocities and coarser substrata compared with pumpkinseed. Also, some individual brown trout preferred deeper waters than did pumpkinseed. Home range area of brown trout was substantially larger than that of pumpkinseed in spring and summer, and for both species, home range area in autumn was significantly smaller than in the other seasons. Range centre distribution analysis revealed that both species were distributed significantly nonrandomly within the stream during all seasons. There was substantial home range overlap between the two species in all seasons, the greatest being in spring. Overall distances moved were greatest during spring for both species, with brown trout moving greater distances relative to pumpkinseed. However, the absence of mutual attraction or avoidance between the species, as well as the lack of cohesion in preferred habitats and strong territorial fidelity, suggests little or no impact of introduced pumpkinseed on resident brown trout.     

高SO4^2-离子腐蚀区钻孔灌注桩防腐措施

在受污染地区进行基础建设时，需考虑结构防腐问题，国内外曾发生过多起由于防腐处理不好而造成结构报废的重大事故。介绍了济南顺河高架桥施工过程中的砼防腐技术。     

Patterns of movement and habitat use by tigerfish (Hydrocynus vittatus) in the Upper Zambezi River (Namibia)

Abstract – During 6 November to 24 December 2000, 23 tigerfish [( Hydrocynus vittatus ), 30–54 cm] were tagged with radio transmitters in the Zambezi River (Namibia) to record habitat utilisation during low, rising and high water levels. The fish were tracked, on average, every fourth day during 23 November to 18 May. Two movement patterns were detected. Approximately 50% of the fish moved <1000 m among tracking surveys, staying within 'defined' home ranges. The remaining fish showed consistent site fidelity for periods, with long distance movements (>1000 m) to new areas among residency periods. Overall, mean distance moved between tracking surveys was 1447 m. Home range size varied among individuals, with a 95% probability of localisation within an average area of 276,978 m². The fish utilised a mean river stretch of 18,836 m (range = 90–71,840). All the fish were recorded in the main stem, and on average, 95% of the fixes were in the main stem during low water. However, the fish used temporary flooded areas to an increasing extent during the rising and high water period, but did not undertake long-distance migrations into the floodplains. Fish were sometimes near vegetation, but were never recorded into or under vegetation.     

基于现代通信技术的海洋渔业互联网初探

近年来,基于计算机技术的互联网发展迅速,促进了各个行业的安全生产、高效管理。但是,传统的互联网只局限于便于布线的陆地,对于辽阔的海洋则无能为力。随着现代通信技术的日新月异,互联网的发展将从有线到无线,互联网的使用将延伸到广阔的海洋,这样的平台将为我国海洋渔业的信息化提供有力的支持。本文从适于海洋环境的CDMA近海通信和移动卫星全球通信及二者均可接入互联网的角度,结合已有的实例,探讨不久的将来,“全国海洋渔业安全通信网”拓展海洋渔业互联网的可能性。