III-Vs — the tip of the spear

GaAs and related compound semiconductors have military origins and the past decade has seen devices based on them being successfully battle-tested. Radar systems are the leading application for these materials, while other important areas include secure military radios, global positioning system (GPS) navigation, night-vision and other enhancements to the battlefield and naval warfare. All of these applications rely on the improvement in sensing and detection that III-V-based devices can confer. This article looks at some of the most interesting defence uses of compound semiconductors, such as phased array radars and missiles.     

Improving the Covertness in the Physical-Layer Authentication

A well-designed Physical-Layer Authentication(PLA)scheme should consider three properties:covertness,robustness,and security.However,the three properties always cause some dilemmas,e.g.,higher covertness leading to lower robustness.This paper concerns the problem of improving the covertness without sacrificing the robustness.This problem is important because of the following reasons:reducing the errors in recovered source message,improving the security,and ease of constructing a multi-factor authentication system.In this paper,we propose three covert PLA schemes to address the problem.In the first scheme,we improve the covertness by reducing the modification ratio on the source message based on an encoding mechanism.In the second scheme,we improve the covertness by optimizing the superimposing angle,which maximizes the minimum distance between the tagged symbols and the boundary line of the demodulation decision for the source message.In the third scheme,referred to as the hybrid scheme,we further improve the covertness by jointly using the advantages of both the above two schemes.Our experimental results show that when the SNR at a legitimate receiver is 25 dB,as compared with the prior scheme,the first scheme improves the covertness by 17:74%,the second scheme improves the covertness by 28:79%,and the third scheme improves the covertness by 32:09%,while they have similar robustness as Received:Aug.07,2020 Revised:Sep.08,2020 Editor:Nanrun Zhou that of the prior scheme.     

Design of the Test System for the Dynamic Function of the SLC PCB

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An Analysis of the Correlation between the Economic Barometer and the Postal Service

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Effect on the Propagation Characteristics of the Electromagnetic Waves by the Second-order Radiation of the Moving High-speed Train＊

The effect on the propagation characteris- tics of the electromagnetic waves by the second-order ra- diation of the moving high-speed train is analyzed in this paper. Two Lorentz transformations, one from the sta- tionary reference coordinate system to the moving system and the other vice versa, are employed to derive the the- oretical model for analysis of the propagation characteris- tics of the vertical polarized plane time-harmonic waves, which is oblique incidence to the train. The calculation re- suits show that for the transmitting wave reflected by the moving high-speed train, two main signals can be received. One is at the transmitting frequency and the other is at the second-order radiated frequency. The frequency spectrum between these two frequencies are much larger than which is introduced by the Doppler shift. The frequency and the reflection angle of the reflected wave are no longer equal to the frequency and the incident angle of the incident wave. The changed reflection frequency and angle are related to the train＇s velocity, the incident angle and the azimuth an- gle of the incident wave. The frequency shift is mainly decided by the y-component of the train＇s velocity. It has nothing to do with y-component of the train＇s velocity. The reflection angles will be smaller than the related incident angles when the train goes along --y direction. The reflec- tion angles will be larger than the related incident angles when the train goes along ＋y direction. The reflection an- gle will become larger and larger with the increase of the incident angle and the y-component of the train＇s velocity. The induced current density and the charge density on the surface of the train are increased with the train＇s velocity, and the induced charge is much smaller than the induced current.     

Study on the Complexity of the Bullwhip Effect

Recent years have witnessed a rapid growth of interest in the study of the dynamic behavior of replenishment rules of bullwhip effect. We prove that bullwhip effect and butterfly effect share a same the self-oscillation amplifying mechanism that is the ordering decisions the supplier self-oscillation amplify the perturbations brought by the errors in the processing of retailers' demand information. This results as an explicit self-similar structure of the sensitivity of the system to the initial values duty to the nonlinear mechanism. In this paper, the causes process of the bullwhip effect is described as the internal nonlinear mechanism and study on the complexity of bullwhip effect for order-up-to policy under demand signal processing. The methodology is based on fractal and chaotic theory and allows important insights to be gained about the complexity behavior of bullwhip effect.     

From the Editor

第四届移动通信产业(移动应用)国际论坛亮相天津；泰尔网隆重举办“2004年中国通信产业十大关键词”活动。     

Implementation of the Broad-band User Access Network and the Study of the Key Algorithm for Improving the Performance of Asymmetrical Networks

Implementation of the Broad-band User Access Network and the Study of the Key Algorithm for Improving the Performance of Asymmetrical Networks     

China Telecom： the Giant in the Post-reorganization Era

Recently, China Mobile launched a large-scale TD promotional activities with terminal subsidies about 1,000 - 1,500 RMB for each new TD user. The total amount of budget subsidies is about 100 million RMB, accounting for over 60 percent of the TD terminal sales price. China Mobile is trying to lower down the users＇ purchase threshold through this method, and to expand the scale of TD users as soon as possible before the Beijing Olympic Games.     

The Study on the Variation of the Cavity Length''''s Influence on the Output Pulse Train of the Actively Mode-Locked Fiber Laser

1 Introduction The actively mode-locked fiber laser is a very poten-tially valuable light source applied to ultrafast OpticalTi me Division Multiplexed ( OTDM) communicationsystems,optoelectronic sampling systems ,etc .,for itcan generate very short (the duration of the pulseisjustseveral ps or evenless) ,highrepetition-rate (the repeti-tion-rate can be 40 GHz or more) optical pulse train.However ,fiber ringlasers are very sensitive to environ-mental perturbations such as temperature fluct…     

From the Editor

~~近期要闻     

Instrumenting the World

1 An Introduction to Wireless Sensor Networks On an uninhabited island off the coast of Maine, tiny wireless sensors deep in the burrows of mysterious sea birds monitor the environmental factors affecting the shy creatures' comings and goings. In one of Intel's chip fabrication facilities, similar sensors measure the subtle vibrations of various machines to detect malfunctions before the equipment     

From the Editor

“山雨欲来风满楼”。随着C N G I项目的启动,我们已经可以依稀听到N G N 临近的脚步。今年2月,在国际电信联盟的积极努力下, N G N 的定义终于尘埃落定。而从今年4月起,国内有关N G N 的研讨和交流活动,如2004年全球IPv6高峰论坛、2004全球N G N 高峰论坛、下一代通信“网络融合与汇聚国际论坛暨峰会”等也陆续在北京各大会议中心隆重召开,声势浩大。 值得一提的是,在由信息产业部电信研究院(以下简称“我院”)主办的“ 2004全球N G N 高峰论坛”开幕式上,国际电信联盟标准化局局长赵厚麟亲自到会并为论坛…     

The Application of the Theory of the Price Elasticity of Demand to the EMS Management

1　Introduction　ExpressMailService (EMS )wasopenedupbyChinaPostintheearly 80stomeettheneedsofeco nomicdevelopment.It sthemostcompetitiveoneofthepostservices.There recivilaviation ,Chinarail wayandotherprivateexpressdeliverycompaniesdomesticallyandUPS ,TNT ,DHLandTEDEXcompetingwithEMSintheinternationalmarket.OneofthemostpowerfulcompeteweaponofthesecompaniesisthelowerpricethanEMS[1 ] .BecauseofthefiercecompetitionEMSdeclinedfromthemo nopolistindomesticandinternationalmarketoftheear…     

To the understanding of the formation of the III–V based droplet epitxial nanorings

The paper deals with the kinetics of the droplet epitaxial GaAs quantum ring formation grown on AlGaAs (0 0 1) surface. The observation is, that the aspect ratio of these nano structures is depends not only on the technological parameters but on the size of the initial droplet. Under appropriate growth conditions, the depressions, in the middle of the rings are deeper than the surface level of the substrate. A large number of tests show, that the depressions in the middle of the small rings are often deeper than that of the larger ones. The number is larger, than just statistical fluctuation. An explanation for this phenomenon and its kinetics are given in the paper, based on the size dependence of the material properties, like for instance solubility. The plausible explanation assumes is that the probability of the crystal seed formation in the larger droplets is higher.     

From the Editor

中国各大运营商的ARPU值在近两年内都出现了较明显的下滑，这使各个运营商都深剖地意识到，随着市场竞争的加剧，单靠话音类业务来维持较高的ARPU值是非常不现实的。为了在新一轮的电信业务市场竞争当中占领市场制高点，提高用户的忠诚度，提供大量优秀的差异化业务迫在眉睫。     

Discourses of the wound and desire for the Other: remembrances of the Katyń massacre and the Smoleńsk crash

ABSTRACT

We investigate the commemorative debate in Polish newspapers about how the Katyń massacre and the presidential plane crash near Smoleńsk, Russia, should be remembered. We demonstrate that a psychoanalytic discursive analysis elucidates the insistence on remembering past wounds, nationalist politics of victimhood, and the difficulties in reaching rapprochement in intercultural relations. To this end, we analyze the commemorative debates in two main Polish newspapers and a news magazine. We argue that an emotive discourse of “Katyń as a wound” yearns for a therapeutic healing of the rifts in Polish national mythology and postcommunist identity. This discourse revolves around a demand for recognition from the Russian Other of a wounded subject by employing evocative metonymies and transposing logics of equivalence and difference.