EXPERIMENT OF SHORT WAVE COMMUNICATION AND THE INVESTIGATION OF THE PROPAGATION BEARINGS BETWEEN THE GREAT WALL STATION AND XINXIANG

The distance from the Great Wall Station (62.2°S, 58.9°W) to Xinxiang (35.3°N, 113.8°E) is 16981 km. The path passes through the polar cap absorption region and the auroral absorption zone, and it is across the equator.In this paper firstly the effects of short wave communication and usable time blocks and frequency ranges between the Antarctic Great Wall Station and Xinxiang from December 1985 to March 1986 are introduced. The comparison between the usable frequency ranges with the estimated MUF is made. The upper limit of frequency ranges of communication along the short great circle path basically agrees with the MUF but there is difference between them along the long great circle path.Secondly, the result of the propagation bearings experiment in January to February 1986 is introduced in more detail, The propagation along the great circle path from the Great Wall Station to Xinxiang is the main propagation mode. But the propagation along non great circle paths occurs at times between Great Wall Station and Xinxiang. The non great circle path propagation varies with time because the ionospheric absorption and other conditions which support the non great circle path propagation are the function of the time. So the courses of the non great circle path propagation may be different in the different time. The mechanism of the constructing non great circle path propagation has been analysed. We preliminarily think the main cause of propagation along non great circle path is the ground scatter. The stronger radialization of the side lobes of the antenna and the less absorption of the ionosphere contribute to forming non great circle path propagation.

Impact Analysis of Electromagnetic Radiation from Communication Stations

[Objective] The study aims to analyze the effects of electromagnetic radiation from the communication stations on on surrounding environment. [ Method] The electromagnetic field intensity of the environment around communication stations was detected firstly, and then the impact of electromagnetic radiation from the communication stations on surrounding environment was analyzed, finally a series of countermeasures and suggestions were proposed to prevent electromagnetic radiation pollution. [ Result] The comprehensive electromagnetic field intensity of the environ- ment around mobile stations has positive correlation with the number of transmitting and receiving antennas. In addition, the comprehensive electro- magnetic field intensity is higher at high points compared with that at low points, showing that the comprehensive electromagnetic field intensity is positively correlated with point height. [ Conclusion] The research is of important significance to environmental protection and public health.

Soft Base Station Technology in Wireless Communication Systems

With the rapid development of wireless communications systems, different system standards are being merged. Operators take stringent measures to reduce Operational Expenditure （OPEX） and Capital Expenditure （CAPEX）; and as a result, soft base stations supporting multiple standards become the evolutionary tend of wireless base stations. This paper introduces the background of soft base stations and analyzes their architecture design, system modules. The key technologies in system implementation and future directions are also presented.

Location correction technique based on mobile communication base station for earthquake population heat map

China has mobile phone penetration rate of over 96.2%.Mobile phone has become the largest Internet terminal for Chinese Internet users.Population geographic distribution in earthquake zones can be got based on mobile phone positioning and map matching.For reducing earthquake black-box stage,we propose a real-time collection,correction and schedule algorithm of population position data by four stream processing environments(Redis,Hbase,Kafka,and Spark Streaming)in this paper.For labeling precisely population geographic distribution on the network map,matching of population geographic coordinates and map coordinates are optimized by sample comparison based on location data of mobile communication base stations and prefecture level cities.The test result shows the proposed system is high efficient and can rapidly respond to any emerging parallel tasks during the earthquake.A high-precision heat map of affected population can be produced and published on-line within 2 min after the devastating earthquake happened.

Analysis of Dispersed Lightning Stroke around a Mobile Communication Base Station

A case of villagers suffering lightning stroke around the tower of a mobile communication base station was investigated to analyze its reasons,and the countermeasures against lightning stroke were proposed. The results show that the lightning stroke event is related to dispersed lightning stroke. To avoid the damage caused by lightning stroke,it is needed to equip a house in the dispersed lightning stroke zone with lightning protection system and spread lightning protection knowledge among the villagers.

Preliminary Design for Station-Keeping of a Communication Satellite

This paper has analyzed the perturbations of a GeoX-Sat （virtual satellite） in geostationary orbit （GEO）. And control methods, strategies and calculation processes are designed of the East-West （E/W） station-keeping of the GeoX-Sat. The Attitude and Orbit Control Subsystem （AOCS） provides attitude information and maintains the required spacecraft attitude during all phases of the mission, starting at spacecraft separation from the launch vehicle and throughout its operational lifetime. For the GeoX-Sat exercising design, due to time limitations; only two modes of operation were considered after assumed launching operation： normal and station keeping.

A Review in the Core Technologies of 5G: Device-to-Device Communication, Multi-Access Edge Computing and Network Function Virtualization

5G is a new generation of mobile networking that aims to achieve unparalleled speed and performance. To accomplish this, three technologies, Device-to-Device communication (D2D), multi-access edge computing (MEC) and network function virtualization (NFV) with ClickOS, have been a significant part of 5G, and this paper mainly discusses them. D2D enables direct communication between devices without the relay of base station. In 5G, a two-tier cellular network composed of traditional cellular network system and D2D is an efficient method for realizing high-speed communication. MEC unloads work from end devices and clouds platforms to widespread nodes, and connects the nodes together with outside devices and third-party providers, in order to diminish the overloading effect on any device caused by enormous applications and improve users’ quality of experience (QoE). There is also a NFV method in order to fulfill the 5G requirements. In this part, an optimized virtual machine for middle-boxes named ClickOS is introduced, and it is evaluated in several aspects. Some middle boxes are being implemented in the ClickOS and proved to have outstanding performances.

Research on network integration technology of observation stations

According to the phenomenon of "four more"and"four low "problems in the observation stations,the surface-based meteorological observing system can't adapt to the change of the adaptive observation equipment and reduce of business intensification. A station integrated system is proposed,w hich can be configured,connected and extended to all kinds of observation equipment. And the integrated processor is designed,supporting a variety of communication interface standards. Flexible configuration,connection and expansion betw een conventional and new type of meteorological observation equipment are supported. It is capable for online calibration and maintenance of observation equipment. The effectiveness of automatic observation equipment is totally achieved to provide basic information support for disaster prevention and mitigation and national economic development.

Satellite Communication System Using SSMA Techniques

A satellite communication system consisting of small earth terminals which utilize spread spectrum multiple access (SSMA) techniques is introduced in this paper. Having no master station, the system is distributively controlled. The frequency band used is 6/4GHz.

Distributed power allocation over indoor multi-pico stations

A low-complexity distributed power allocation algorithm is proposed to reduce the interference and improve the transmitting rate of edge users. Different scenarios are considered and user experience of indoor communication is promoted. The simulation results prove the effectiveness of our algorithm. The proposed power control scheme ensures that more users can achieve their required rate and the fairness of different users is improved. Besides, more than 5096 energy can be saved without loss in outage ability, and energy efficiency is also promoted. In addition, the proposed algorithm can be extended to scenarios that the required rates of pico stations can be changed periodically.

AEECA for Reliable Communication to Enhance the Network Life Time for WSN

Nowadays,wireless sensor networks play a vital role in our day to day life.Wireless communication is preferred for many sensing applications due its convenience,flexibility and effectiveness.The sensors to sense the environmental factor are versatile and send sensed data to central station wirelessly.The cluster based protocols are provided an optimal solution for enhancing the lifetime of the sensor networks.In this paper,modified K-means++algorithm is used to form the cluster and cluster head in an efficient way and the Advanced Energy-Efficient Cluster head selection Algorithm(AEECA)is used to calculate the weighted fac-tor of the transmission path and effective data collection using gateway node.The experimental results show the proposed algorithm outperforms the existing routing algorithms.

Energy efficient and delay aware ternary-state transceivers for aerial base stations

In recent times, Aerial Base Stations(AeBSs) are being investigated to provide wireless coverage to terrestrial radio terminals. There are many advantages of using aerial platforms to provide wireless coverage, including larger coverage in remote areas and better line-of-sight conditions, etc. Energy is a scarce resource for the AeBSs, hence the wise management of energy is quite beneficial for the aerial network. In this context, we study the means of reducing the total energy consumption by designing and implementing an energy efficient AeBSs as presented in this paper. Implementing the sleep mode in the Base Stations (BSs) has been proven to be a very good approach for improving the energy efficiency and we propose a novel strategy for further improving energy efficiency by considering ternary state transceivers for AeBSs. Using the three state model, we propose a Markov Decision Process (MDP) based algorithm, which intelligently switches among three states of the transceivers based on the offered traffic meanwhile maintaining a prescribed minimum channel rate per user. We define a reward function for the MDP, which helps us to get an optimal policy for selecting a particular mode for the transceivers of the AeBS. Considering an AeBS with transceivers whose states are changeable, we perform simulations to analyse the performance of the algorithm. Our results show that, compared with the always active model, around 40% gain in the energy efficiency is achieved by using our proposed MDP algorithm together with the three-state transceivers model. We also show the energy-delay tradeoff in order to design an efficient AeBS.

Electromagnetic Environment Impact of Mobile Communication Iron Tower on Adjacent Building and Its Countermeasures

For several lightning-strike disasters related to base station iron tower of mobile communication carrier operator, disaster-inducing factors were analyzed. The reason was as below： after lightning receptor of base station iron tower of mobile communication carder operator was struck by lightning, electromagnetic radiation was generated in the process lightning current leaking into the ground. In addition, it was lightning scattered- strike phenomenon induced by overhead lightning rod, that is, ground lightning falling density around overhead lightning rod was larger than mean at the site. Finally, some improvement measures were put forward.

Design of Station Keeping Mode for Attitude Orbit Control Subsystem of T-SAT

Station keeping mode （SKM） for Attitude Orbit Control Subsystem （AOCS）; it is an operational approach regarding the attitude dynamics control. The essential features of the design methodology is researching the basic theory and then afterwards, make an iterative design approach using some premise/assumptions, implementing the system simulation through the Simulink Matlab software package, designing the required controllers, monitor and analyzing the responses until the design give the best results within the range required. Firstly the thruster configuration is designed to acquire the parameters of the torque on the satellite. Next, the controllers are based on the well known PID control law. Controllers optimize the attitude and are used during the maneuvers for SKM. Afterwards the simulation results are given, and presented to demonstrate the performance and validity of the AOCS design approach. Finally the simulation results demonstrate that all the requirements were accomplished and the Station Keeping Mode was successfully designed.

日本海军对中国东北领水测量探析(1931-1937)

九一八事变后,日本殖民者为掌握中国东北的地理与水文情况,在1932年操纵伪满政权将领土测绘工作交给关东军。限于军种职能不同,领水测量权被转让给日本海军,由下属机构水路部与驻满海军部负责调查领海、勘测河道、建设航标等任务。此外日本海军利用伪满苏水路会议,借机盗测苏联边境,妄图为己方牟利。日本海军对东北领水的测量活动随驻满海军部撤销而结束,测量成果有限度地促进了日占东北航运事业的恢复与发展,但同时为日军镇压抗日武装、研究对苏战略提供帮助,这一活动本质上是隐藏在科研调查下的殖民侵略,是对我国领海主权的严重侵犯。

国有林区战略转型中的管理体制改革——大兴安岭十八站林业局综合改革试点调研报告

大兴安岭十八站林业局综合改革的主要做法：分解职能,整合精简局机关;统筹社会事务,模拟政企分开管理;剥离辅业单位,推行市场经营;组建专业公司,模拟法人独立经营;实施林场转型,模拟事业化管理;创新用工分配机制,综合配套推进改革。提出目前存在问题及解决建议。

北京近代警察制度之区划研究

北京近代警察制度从光绪二十七年 (190 1年 )开始尝试建立 ,经过近一个世纪的发展不断走向成熟。专业的警察机关逐步设立 ,城市警政架构不断完善。这一过程是北京城市现代化的重要组成部分。而北京警察制度现代化的另一个重要表现和作用就是引入了城市分“区”的概念。伴随着北京警察制度的发展变迁 ,“区”从最初的警务区划最终发展成为现代城市独立的行政单位。

高压输电系统对通信局(站)危险影响中地电流系数的确定

高压输电系统发生接地短路故障时,会产生一个地电位升,对通信局(站)会危险影响,为了计算这个危险影响的大小,首先能够准确的计算出高压输电系统的地电流系数。本文论述了高压输电系统对通信局(站)危险影响中地电流系数的确定,介绍了地电流系数的定义,并分析了不同危险情况下地电流系数的计算。

浅谈局域网安全策略的设计与实现

详细阐明了如何打造安全的局域网,其中包括安装安全的Windows2000服务器,配置Win dows2000服务器提高安全性能,及局域网内工作站上网安全防护措施。