• Title/Summary/Keyword: back-to-back channels

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GPS/INS Integration using Vector Delay Lock Loop Processing Technique

  • Kim, Hyun-Soo;Bu, Sung-Chun;Jee, Gyu-In
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.2641-2647
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    • 2003
  • Conventional DLLs estimate the delay times of satellite signals individually and feed back these measurements to the VCO independently. But VDLL estimates delay times and user position directly and then estimate the feedback term for VCO using the estimated position changes. In this process, input measurements are treated as vectors and these vectors are used for navigation. First advantage of VDLL is that noise is reduced in all of the tracking channels making them less likely to enter the nonlinear region and fall below threshold. Second is that VDLL can operate successfully when the conventional independent parallel DLL approach fails completely. It means that VDLL receiver can get enough total signal power to track successfully to obtain accurate position estimates under the same conditions where the signal strength from each individual satellite is so low or week that none of the individual scalar DLL can remain in lock when operating independently. To operate VDLL successfully, it needs to know the initial user dynamics and position and prevents total system from the divergence. The suggested integration method is to use the inertial navigation system to provide initial dynamics for VDLL and to maintain total system stable. We designed the GPS/INS integrated navigation system. This new type of integrated system contained the vector pseudorange format generation block, VDLL signal processing block, position estimation block and the conversion block from position change to delay time feedback term aided by INS.

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Channel Resource Allocation Scheme Provided for Fair QoS in ECMA-392-Based Ship Area Networks (ECMA-392 기반 선박 내 네트워크에서 Fair QoS 제공을 위한 채널 자원 할당 방안)

  • Lee, Seung Beom;Back, Jong Sang;Park, Soonyoung;Lee, Seong Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.12
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    • pp.1280-1288
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    • 2014
  • In this paper, we use the ECMA-392 standard, the first cognitive radio networks to meet the demand for IT services in the ship. First, we learn about ECMA-392-based network and examine the consideration and the problems for assigning channels to the device. And, we propose a fair channel resource allocation to ensure efficiently channel required by device groups in ECMA-392 MAC protocol. This is a method to reallocate the channels fairly with considering the channel assignment parameters to a new device group and existing device groups. The simulation results show that the proposed scheme improves throughputs compared to the existing one.

Artificial Photosynthesis Using Zeolites

  • Castagnola, Norma B.;Dutta, Prabir K.
    • Journal of Photoscience
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    • v.6 no.3
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    • pp.91-96
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    • 1999
  • Zeolites and microporouos materials continue to attract attention as novel hosts for photochemical reactions. Zeolities are attractive because of their ability to selectivity exchange and incorporate species within the void spaces and interconnecting channels, providing a spatial arrangement of molecules. Our research has primarily focused on intrazeolitic electron transfer from excited Ru(bpy)32+ in supercages of zeolite Y to a series of bipyridinium ions. In the Ru(bpy)32+ viologen-zeolite Y samples, the slowing of the back electron transfer from the bipyridinium radical cation to Ru(bpy)32+ allows for charge propagation via self exchange between diquat molecules. This provides an opportunity for permanent charge separation. When the migrating charge on the diquat radical within the zeolite reaches the surface, it can be transferred to a neutral viologen (PVS) in solution, resulting in permanent charge separation. The advantage of long-lived charge separation can be exploited for useful chemistry if suitable catablysts can be assembled on the zeolities. We have studied Ru(bpy)2 as water oxdiation catalysts. We have demonstrated that synthesis of RuO2 fibers on a zeolite via thermal decomposition of Ru3(CO)12 leads to the most active water decomposition catalyst reported to date. Because of the extensive interest of photochemical water reduction to H2, much is known about catalytic systems usin gone electron catalyst, and even more importantly, that no reaction of viologen occurred with H2 over this catalyst. The present challenge is to incorporate all these elements of the system into an architecture and we are examining zeolite membranes for this purpose.

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Development of Inspection System for Transparent Pattern of the Electromagnetic Resonance Pen (전자펜 입력용 투명패턴 검사장치 개발)

  • Ryu, Young Kee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.640-645
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    • 2020
  • To produce an input device stably using the transparent electromagnetic pattern of an electromagnetic induction method, pattern inspection is required in advance in the production process. Various methods of inspecting the capacitive pattern for hand-touch have been proposed, but it is difficult to find the related technical data for the pattern inspection method of the transparent electromagnetic induction method. In this study, to develop an inspection system for a fused electromagnetic resonance pen sensor with a copper-etched metal mesh pattern, an inspection algorithm and method for measuring the antenna impedance inside the sensor was proposed by measuring only the exposed FPCB connector. The proposed method was configured as a control board consisting of a microprocessor that forms a loop between specific channels according to the command of a computer, a computer-controlled by the Windows program, an LCR meter measuring the impedance between specific channels, and transmitting the measurement results back to the computer. An evaluation of the proposed system and measurements of nine specimens showed that it could detect the defects of the sensor used in the actual product.

Experimental Study on the Heat Distribution in the Rectangular Mini Channel Heat Exchangers with MPCM Slurry (마이크로 캡슐 잠열재 슬러리를 적용한 미소채널 열교환기의 열분배 성능평가)

  • Jeon, Jong-Ug;Back, Chang-Huyn;Kim, Yong-Chan;Kim, Young-Deug;Choi, Jong-Min
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.645-650
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    • 2006
  • The heat transfer performance and energy transport ability are relatively high due to higher specific heat. Therefore, it can be used in fields such as heating, ventilating, air-conditioning, refrigeration and heat exchangers. In this study, liquid-cooling heat exchangers were designed and tested by varying geometry and operating conditions. In addition, liquid-cooling heat exchangers were tested to provide performance data for MPCM slurry. The liquid-cooling heat exchangers had twelve rectangular channels with flow paths of 1, 2, 4 and 12. Silicon rubber heaters were used to control the heat load to the heat exchanger. Heat input ranged from 293 to 800 W, and inlet temperatures of working fluid varied from 15S to $27^{\circ}C$. The standard deviation of surface temperature was strongly affected by the coolant of MPCM Slurry, All MPCM-cooling heat exchangers showed higher cooling performance than the water-cooling heat exchanger except one path channel heat exchanger.

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A Single Feedback Based Interference Alignment for Three-User MIMO Interference Channels with Limited Feedback

  • Chae, Hyukjin;Kim, Kiyeon;Ran, Rong;Kim, Dong Ku
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.4
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    • pp.692-710
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    • 2013
  • Conventional interference alignment (IA) for a MIMO interference channel (IFC) requires global and perfect channel state information at transmitter (CSIT) to achieve the optimal degrees of freedom (DoF), which prohibits practical implementation. In order to alleviate the global CSIT requirement caused by the coupled relation among all of IA equations, we propose an IA scheme with a single feedback link of each receiver in a limited feedback environment for a three-user MIMO IFC. The main feature of the proposed scheme is that one of users takes out a fraction of its maximum number of data streams to decouple IA equations for three-user MIMO IFC, which results in a single link feedback structure at each receiver. While for the conventional IA each receiver has to feed back to all transmitters for transmitting the maximum number of data streams. With the assumption of a random codebook, we analyze the upper bound of the average throughput loss caused by quantized channel knowledge as a function of feedback bits. Analytic results show that the proposed scheme outperforms the conventional IA scheme in term of the feedback overhead and the sum rate as well.

Scientific exploration on physiological basis of Svedana Karma (Sudation): A clinical application of heat stress.

  • Yadav, Saurabh;Verma, Vandana;Abhinav, Abhinav
    • CELLMED
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    • v.9 no.3
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    • pp.4.1-4.8
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    • 2019
  • Now researchers have focused attention on exploring the mechanism of acute responses of heat stress given in heat therapy that ultimately promotes the long term health benefits. Heat therapy is not a new idea rather it was practiced since thousands years back in the form of hot bath, sauna bath, steam room. Similarly in Ayurveda there is very comprehensive description of heat therapy in the form of Svedan karma (Sudation therapy). Svedan is a process to induce sweating artificially in a patient who had already undergone Snehan. Svedan is applied for purification of body, as well as in management of various disorders originated due to vitiation of Vata, Kapha Dosha, Meda Dhatu and musculoskeletal disorders. It produces various beneficial effects by augmenting the Agni like clears the channels, liquefies the deposited Dosha, regulates Vata Dosha, helps in removal and pacification of Dosha, augments metabolism (Agni Deepan), increases appetite, flexibility in body parts, softness and shining of skin, removes coldness, stiffness, drowsiness, improves joint motility. However, Svedana karma is vastly used by Ayurveda Physicians in treatment of various disorders but the mechanisms of beneficial effects produced by Svedan Karma are yet not completely explored on scientific basis. In this article, we will discuss and try to establish a possible mechanism of action of Svedana karma in relation to heat stress, mitochondrial adaptation, heat shock protein (HSP) and glucocorticoids as these are secreted under stressful conditions.

Symbol Error Probability of a Physical Layer Network Coded System in Nakagami Fading Channels (나카가미 페이딩 채널에서 물리 계층 네트워크 부호화 시스템의 심볼 오류율)

  • Do, Phu Thinh;Wang, Jin-Soo;Park, Jin-Bae;Kim, Yun-Hee
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.37 no.8C
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    • pp.645-654
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    • 2012
  • In this paper, we consider a two-way relay (TWR) system, where two user nodes exchange their information within two transmission phases, by the help of a relay node adopting physical layer network coding. In the system, two users transmit their binary phase shift keying symbols simultaneously in the first phase, and the relay node decodes the XORed version of two user data and broadcasts it back to two users in the second phase. The performance of the system is analyzed in terms of the average end-to-end symbol error probability in Nakagami-m fading channels, for which a tight upper bound is derived in a closed form to provide an accurate and handy estimate on the performance. The results show that our upper bounds are almost indistinguishable from simulation results for various channel and system configurations. In addition, the optimal relay location and power allocation for various conditions can be obtained quickly with our analysis.

A study for omega-shaped gate ZnO nanowire FET (Omega 형태의 게이트를 갖는 ZnO 나노선 FET에 대한 연구)

  • Keem, Ki-Hyun;Kang, Jeong-Min;Yoon, Chang-Joon;Jeong, Dong-Young;Kim, Sang-Sig
    • Proceedings of the KIEE Conference
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    • 2006.07c
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    • pp.1297-1298
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    • 2006
  • Omega-shaped-gate (OSG) nanowire-based field effect transistors (FETs) have been attracted recently attention due to their highdevice performance expected from theoretical simulations among nanowire-based FETs with other gate geometries. OSG FETs with the channels of ZnO nanowires were successfully fabricated in this study with photolithographic processes. In the OSG FETs fabricated on oxidized Si substrates, the channels of ZnO nanowires with diameters of about 60 nm are coated surroundingly by $Al_{2}O_{3}$ as gate dielectrics with atomic layer deposition. About 80 % of the surfaces of the nanowires coated with $Al_{2}O_{3}$ is covered with gate metal to form OSG FETs. A representative OSG FET fabricated in this study exhibits a mobility of 98.9 $cm^{2}/Vs$, a peak transconductance of 0.4 ${\mu}S$, and an Ion/Ioff ratio of $10^6$ the value of the Ion/Ioff ratio obtained from this OSG FET is the highest among nanowire-based FETs, to our knowledge. Its mobility, peak transconductance, and Ion/Ioff ratio arc remarkably enhanced by 11.5, 32, and $10^6$ times, respectively, compared with a back-gate FET with the same ZnO nanowire channel as utilized in the OSG FET.

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The Analysis of Local Dabta Communication Line Characteristics (국내 데이타 통신회선의 특성 분석)

  • 김동규
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.16 no.5
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    • pp.1-11
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    • 1979
  • Since the second half of 1960's one of the information industry's most vital, yet least-well-understood areas has evolved-Data communications/Computer communications. To successfully realize this field we have to identity and reveal a variety of fundermental characteristics of communications channels and see their high reliability as prerequisites. This paper has accumulated related data from 1973 on, systematically analyzed them and provided some basic back ground and suggestions. Error rate which is the final and external characteristics of communication lines according to channal types, communication types and speed, block length and geographical difference between test points was extensively examined as well as their frequency response and d-c characteristics. The perspective of 9600BPS high speed data communications was also discussed.

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