• 제목/요약/키워드: transmission capacity

검색결과 1,206건 처리시간 0.025초

A Genetic Approach to Transmission Rate and Power Control for Cellular Mobile Network (ICEIC'04)

  • Lee YoungDae;Park SangBong
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
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    • pp.10-14
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    • 2004
  • When providing flexible data transmission for future CDMA(Code Division Multiple Access) cellular networks, problems arise in two aspects: transmission rate. This paper has proposed an approach to maximize the cellular network capacity by combining the genetic transmission rate allocation and a rapid power control algorithm. We present a genetic chromosome representation to express call drop numbers and transmission rate to control mobile's transmission power levels while handling their flexible transmission rates. We suggest a rapid power control algorithm, which is based on optimal control theory and Steffenson acceleration technique comparing with the existing algorithms. Computer simulation results showed effectiveness and efficiency of the proposed algorithm Conclusively, our proposed scheme showed high potential for increasing the cellular network capacity and it can be the fundamental basis of future research.

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자동변속기 마찰요소의 동특성 해석 (Analysis of Dynamics Characteristics for Friction Elements in Automatic Transmission)

  • 최영종;정우진;김성원
    • 한국자동차공학회논문집
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    • 제5권5호
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    • pp.9-19
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    • 1997
  • In this paper, the modeling and analysis of dynamic characteristics has been carried out for friction clutches and brakes in an automatic transmission. From the operating oil pressure generated by the valve-body, time delay by check valve and the movement of piston has been examined. Also torque capacity and torque transferred at the clutch is studied. Heat capacity and temperature distribution at the reaction plate of clutch are codeled by time-dependent, nonhomogeneous partial differential equation, and brake torque, brake time, and the amount of heat generated are investigated. It is found that the time delay at the check valve is very short but dominant at the spool.

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Study on the influence of structural and ground motion uncertainties on the failure mechanism of transmission towers

  • Zhaoyang Fu;Li Tian;Xianchao Luo;Haiyang Pan;Juncai Liu;Chuncheng Liu
    • Earthquakes and Structures
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    • 제26권4호
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    • pp.311-326
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    • 2024
  • Transmission tower structures are particularly susceptible to damage and even collapse under strong seismic ground motions. Conventional seismic analyses of transmission towers are usually performed by considering only ground motion uncertainty while ignoring structural uncertainty; consequently, the performance evaluation and failure prediction may be inaccurate. In this context, the present study numerically investigates the seismic responses and failure mechanism of transmission towers by considering multiple sources of uncertainty. To this end, an existing transmission tower is chosen, and the corresponding three-dimensional finite element model is created in ABAQUS software. Sensitivity analysis is carried out to identify the relative importance of the uncertain parameters in the seismic responses of transmission towers. The numerical results indicate that the impacts of the structural damping ratio, elastic modulus and yield strength on the seismic responses of the transmission tower are relatively large. Subsequently, a set of 20 uncertainty models are established based on random samples of various parameter combinations generated by the Latin hypercube sampling (LHS) method. An uncertainty analysis is performed for these uncertainty models to clarify the impacts of uncertain structural factors on the seismic responses and failure mechanism (ultimate bearing capacity and failure path). The numerical results show that structural uncertainty has a significant influence on the seismic responses and failure mechanism of transmission towers; different possible failure paths exist for the uncertainty models, whereas only one exists for the deterministic model, and the ultimate bearing capacity of transmission towers is more sensitive to the variation in material parameters than that in geometrical parameters. This research is expected to provide an in-depth understanding of the influence of structural uncertainty on the seismic demand assessment of transmission towers.

Channel Capacity Analysis of DNA-based Molecular Communication with Length Encoding Mechanism

  • Xie, Jialin;Liu, Qiang;Yang, Kun;Lin, Lin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제15권8호
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    • pp.2923-2943
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    • 2021
  • The double helix structure of DNA makes it diverse, stable and can store information with high density, and these characteristics are consistent with the requirements of molecular communication for transport carriers. In this paper, a specific structure of molecular communication system based on DNA length coding is proposed. Transmitter (Tx) adopts the multi-layer golden foil design to control the release of DNA molecules of different lengths accurately, and receiver (Rx) adopts an effective and sensitive design of nanopore, and the biological information can be converted to the electric signal at Rx. The effect of some key factors, e.g., the length of time slot, transmission distance, the number of releasing molecules, the priori probability, on channel capacity is demonstrated exhaustively. Moreover, we also compare the transmission capacity of DNA-based molecular communication (DNA-MC) system and concentration-based molecular communication (MC) system under the same parameter setting, and the peak value of capacity of DNA-MC system can achieve 0.08 bps, while the capacity of MC system remains 0.025 bps. The simulation results show that DNA-MC system has obvious advantages over MC system in saving molecular resources and improving transmission stability.

송전선 이용료상의 적정 신뢰도비용 산정방안 (Allocation of Transmission Reliability Charge)

  • 유청일;신영근;김발호
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2001년도 추계학술대회 논문집 전력기술부문
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    • pp.67-69
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    • 2001
  • It is required to develop a rational transmission tariff system to ensure the fair participation of the players in the market. This study suggests an improved transmission tariff system which classifies the line capacity into line usage and reliability capacity based on their use and reasonably allocates the costs incurred by each of them to users. In addition, it takes the system load variations into consideration.

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EMTP/ATPDraw를 이용한 가스절연송전선로(GIL)의 과전압 분석 (An Analysis on the Overvoltage in Gas Insulated Transmission Lines with EMTP/ATPDraw)

  • 박흥석;한상옥
    • 전기학회논문지
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    • 제60권5호
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    • pp.999-1004
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    • 2011
  • Nowadays, it is becoming difficult to secure a transmission line route when a new transmission line is constructed due to social environment and resident complaints. As existing urban areas are expanded and new cities are constructed, the necessity of high-capacity underground power transmission has been increasing because of load concentration in downtown areas. In North America, Europe and Japan, the research has been carried out for 2nd generation gas insulated transmission lines(GIL) which is more environmentally friendly and economical compared to previous GILs. The new GILs have been applied to real power systems from early 2000s. In South Korea, GIL is being considered as a possible solution for replacing 345kV high-capacity overhead transmission lines with underground transmission ones, so KEPCO is planning to develop and apply a new 362kV rated GIL underground transmission lines instead of overhead transmission lines. In this paper, the overvoltage generated at the combined transmission line adapting GIL was reviewed using EMTP.

한국전력 노후 가공송전선의 동적송전용량에 대한 재평가 (A Reassessment for Dynamic Line Rating of Aged Overhead Transmission Lines in Kepco's Network)

  • 김성덕
    • 조명전기설비학회논문지
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    • 제24권10호
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    • pp.123-129
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    • 2010
  • During the past 2 decades, many electric power companies have been searching various solutions in order to supply power with economical and more efficiency in the present transmission utilities. Most interesting method to increase the line capacity of overhead transmission lines without constructing any new line might be to adapt Dynamic Line Rating(DLR). Specified rating is normally determined by any current level, not by conductor temperature. Although specified rating is essential to design transmission line, dip may be the most important factor in limiting transmission capacity. Transmission lines built by the oldest dip criterion among the 3 different design criteria for conductor dip are nearly over one-half of all Kepco's transmission lines. This paper describes an up-rating method for those transmission lines in order to apply DLR technique. Based on limit dip conductor temperature and current of the transmission lines, limitation performance and effectiveness in applying DLR with weather model are analyzed. As a result of analysis, it can be shown that an improved method could be effectively used for increasing the line rating of old transmission line which was built by the design criterion with low dip margin.

가공송전선의 부하용량과 이도 특성에 관한 실험적 연구 (A An Experimental Study for Load Capacity and Dip Characteristic in Overhead Transmission Lines)

  • 김성덕
    • 조명전기설비학회논문지
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    • 제24권12호
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    • pp.177-183
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    • 2010
  • Overhead transmission lines in domestic area have been built by several different design standards of dip and ground clearance. This paper describes an experimental study for evaluating load capacity and dip margin in overhead transmission lines. Such design standards for selection of overhead transmission conductors, dip and ground clearance, as well as electrical equipment technical standard are discussed. Based on daily load and weather data, several characteristics such as line utilization factor, load factor, conductor temperature and dip, etc. are analyzed, and compared with the specified levels of design standards. As a result, it is verified that DLR method can be a clue of the solving of the problem, for occurring in old transmission conductors which may be rarely operating below standards.

Inline 분산 제어가 적용된 WDM 시스템에서 전송 용량에 따른 전송 거리 (Transmission Distance Depending on Transmission Capacityin Inline Dispersion Managed WDM Systems)

  • 이성렬;조성언
    • 한국정보통신학회논문지
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    • 제13권5호
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    • pp.959-966
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    • 2009
  • Inline 분산 제어 (DM; dispersion management)와 전체 전송로 중간에 광 위상 공액기 (OPC; optical phase conjugator)를 갖는 WDM 시스템의 전송 용량에 따른 유효 전송 거리를 살펴보았다. 그리고 후치 보상량 (postcompensation)만으로 제어되는 1 Tbps WDM 시스템에서 1 dB 눈 열림 패널티 (EOP; eye opening penalty)를 얻을 수 있는 전체 잉여 분산 (NRD; net residual dispersion)의 범위를 살펴보았다. NRD를 시스템 전송 용량과 거리에 따라 최적화시킴으로써 유효 전송 거리가 수 백 킬로미터 이상 증가되는 것을 확인하였다. 그리고 1 Tbps WDM 시스템에서 NRD가 +17 ps/nm로 결정되면 최대 전송 거리를 얻을 수 있고, 특히 장거리 1 Tbps WDM 전송에서 유효 NRD 범위는 양의 값 내에서 결정되어야 하는 것을 확인하였다.

농업용 트랙터의 전후진 파워시프트 변속 특성 해석 (Analysis of Power Shuttle Characteristics of Agricultural Tractor)

  • 김대철;이호상;정병학;김경욱
    • Journal of Biosystems Engineering
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    • 제27권6호
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    • pp.479-490
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    • 2002
  • A dynamic model of a power shuttle transmission was developed and its validity was verified using the experimental data obtained from a transmission test bench. A 40㎾, 4WD tractor was also modeled using an application software EASY5 to investigate parameters and their effects on the power shifting performance. For a tractor model, the manual reverse gear was replaced by a power shuttle transmission. The tractor model also included an engine, main-gears for transmission, wheels, differentials and planet gears. Using the tractor model, the effects of the parameters such as modulating pressure and time, engine speed, tractor speed. tractor weight. reverse to forward speed ratio and torsional damper on the transient characteristics at starting and shuttle shifting were investigated by the computer simulation. The transient characteristics were represented by variations in clutch pressure, torque transmitted to input shaft and driving wheels, and power transmission capacity of the clutch. It was found that the modulating pressure and time affected most significantly the torque transmission and shifting time. The input torque, axle torque, power transmission capacity of the clutch and transmission time all increased with increase in engine speed, tractor speed. tractor weight and ratio of reverse to forward speeds. However, the axle torque decreased with tractor speed. Both the axle torque and power transmission capacity of the clutch also decreased with the ratio of reverse to forward speeds.