• 제목/요약/키워드: Transmission rate

검색결과 3,608건 처리시간 0.036초

CDMA 이동통신시스템에서의 저속 멀티미디어 서비스를 위한 호 수락 방식 (Call admission scheme for low speed multimedia services in CDMA mobile communication systems)

  • 최경수;권수근;전형구;유영갑
    • 전자공학회논문지S
    • /
    • 제35S권7호
    • /
    • pp.14-21
    • /
    • 1998
  • In providing with low speed multimedia services, a call blocking rate is greatly varied according to the transmission rate, and thereofr, the call blocking rate is remarkably increased for a service having a high transmission rate compared to a service having a low transmission rate. This paper presents three methods of solving this problem; Packing Scheme in which available channels distributed to each frequency channel are concentrated on one frequency channel and a call having a high transmission rate is assigned to the frequency channel; Queuing Scheme in which queuing is assigned to calls under service is temporarily reduced and a call having a high transmission rate is allowed. The result of performance analysis for 13 Kbps and 128 Kbps service through computer simulation showed that the call blocking rate for 128 Kbpx service was reduced by tens of percent accoring to loads.

  • PDF

적응형 대역폭 할당 방법을 위한 효율적인 전송 계획 (An Efficient Transmission Plan for Adaptable Bandwidth Allocation Technique)

  • 이면재;박도순
    • 정보처리학회논문지C
    • /
    • 제14C권3호
    • /
    • pp.285-292
    • /
    • 2007
  • 적응형 대역폭 할당 방법에서는 가변 비트율로 저장된 비디오 데이터에 대한 전송 계획을 세우고 네트워크 트래픽을 고려하여 전송하는데, 전송 계획으로 CBA 알고리즘이 사용된다 그러나, CBA 알고리즘에서는 전송률 증가 구간의 크기가 감소 구간의 크기보다 일반적으로 크며, 전송률이 증가될 때에 오버플로우 경계선에서 전송률이 변화되므로 가용 전송률이 작은 경우에는 폐기되는 프레임의 양이 많아지게 된다. 본 논문에서는 이를 개선하기 위하여 언더플로우 경계선과 오버플로우 경계선의 중간에서 전송률이 변화되지만, 전송률의 증가가 필요한 경우에는 증가 양을 최소로 하는 스무딩 알고리즘을 제안한다. 제안 알고리즘과 CBA 알고리즘을 적응형 대역폭 할당 방법의 전송 계획으로 사용하였을 때, 최소 재생률, 평균 재생률, 재생률 변화량, 그리고 폐기되는 프레임 양을 비교하여 제안 알고리즘의 성능이 우수함을 보였다.

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

  • Lee YoungDae;Park SangBong
    • 대한전자공학회:학술대회논문집
    • /
    • 대한전자공학회 2004년도 ICEIC The International Conference on Electronics Informations and Communications
    • /
    • pp.10-14
    • /
    • 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.

  • PDF

가시광선영역에서 shade guide에 따른 광투과도 특성 연구 (ANALYSIS OF OPTICAL TRANSMISSION CHARATERISTICS BY VISIBLE LIGHT INTO SHADE GHIDES)

  • 최근배;박찬운;송창용;고석민
    • 대한치과보철학회지
    • /
    • 제38권2호
    • /
    • pp.147-159
    • /
    • 2000
  • The purpose of this study was the evaluation of spectral transmission of the commercial three shade guides and the relationship of hue, value, and chroma according to the transmission rate. The spectral transmittance of three shade guides - Vita Lumin Shade Guide, Vintage and Unibond Shade Guide, and Vitapan 3D-Master Shade Guide - were measured. For direct transmission measurements, each shade tabs were placed at the entrance port of the 1mm diameter intergrating sphere. The intensity of the light source passing through the shade tabs to the right angle was continuously recorded for wavelength from 400 to 700 nm. A transmission spectrum and digital data were obtained for each measurement and they were evaluated using Microcal Origin program. The obtained results of this study were as follows : 1. In Vita Lumin Shade Guide, sum of the transmission rate of the shade tabs at the wavelength 400-700nm was decreased in agreement with the arrangement order at each A, B, C, D group, except D4 shade tab. However, there were no relationships between the transmission rate of the shade tabs and the value-oriented. 2. In Vintage and Unibond Shade Guide, sum of the total transmission rate of the shade tabs was decreased in agreement with the arrangement order at each A, B, C, B group. When all shade tabs arranged in value-oriented, transmission rate was accord with the order, except D4 shade tab. 3. When shade tabs of the Vitapan 3D-Master Shade Guide have the same value and hue, sum of their total transmission rate decreased in accordance with the chroma-oriented. When the shade tabs have the same value and chroma, there were no differences from the order of the transmission rate to the various hue type. However, in the 'R' tabs of reddish hue type, the transmission rate increased at the long wavelength range area. In conclusion, we need the quantitative analyzing instruments in transmission determination. Vitapan 3D-Master Shade Guide covers the tooth color space taking into account the parameters of the systematic value, chroma, hue oriented, and the transmission rate relatively accorded with that sequence.

  • PDF

중재계임을 이용한 송전비용배분비율 결정에 관한 분석 (Analysis on the Decision of Transmission Cost Allocation Rate Using the Arbitration Game)

  • 정구형;유청일;강동주;한석만;김발호
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 2002년도 추계학술대회 논문집 전력기술부문
    • /
    • pp.375-377
    • /
    • 2002
  • In many parts of the world. the electricity industry is undergoing unprecedented changes. Hence, in order to reform the electricity industry readily and efficiently and minimize the confusion by these restructuring, it is required the systematic studies related to transmission pricing and transmission cost allocation issues. However, even now the basis of transmission cost allocation rate is not equipped so that the regulation body has determined the allocating rate under the common practice. In this paper it is demonstrated that the decision of transmission cost allocation rate is the regulation body's own right. For the analysis, game theory is applied to the procedure determining this rate and the competition to determine this rate between generators and distributors is modeled as the arbitration game.

  • PDF

스무딩 알고리즘들의 버스트 성능 평가 (Performance Evaluation focused on Burst of Smoothing Algorithms)

  • 이면재
    • 디지털콘텐츠학회 논문지
    • /
    • 제13권1호
    • /
    • pp.111-118
    • /
    • 2012
  • 버스트는 가변 비트율로 저장된 비디오 데이터를 전송하려는 경우 급격하게 높은 전송률이 요구되는 것으로 네트워크 자원의 비효율적인 사용의 원인이 될 수 있다. 스무딩은 이를 방지하기 위해 가변 비트율로 저장된 비디오 데이터를 고정 비트율로 변환하는 전송 계획을 세우는 기법으로, CBA, MCBA, MVBA 알고리즘들이 있다. 본 논문에서는 기존 CBA, MCBA, MVBA 알고리즘들의 버스트 감소 정도를 평가하기 위해, 가변 비트율로 저장된 비디오 소스와 스무딩 알고리즘에서의 전송 계획을 버스트에 영향을 미치는 요소들로 비교한다. 사용된 평가 요소는 최대 프레임 바이트 수, 최대 GOP 바이트 수, 프레임당 전송률 변화량, GOP당 전송률 변화량이다. 실험 결과, 실험에 사용된 모든 스무딩 알고리즘들의 버스트 관련 평가 요소들이 특정한 경우를 제외하고 원래 비디오 소스보다 낮았다.

IEEE 802.11e HCCA MAC의 다중 전송률을 이용한 멀티미디어 트래픽의 효율적 전송 (Efficient Delivery of Multimedia Traffic Using Muti-rate Transmission of 802.11e HCCA MAC Protocol)

  • 김영환;석정봉
    • 한국통신학회논문지
    • /
    • 제33권4B호
    • /
    • pp.192-198
    • /
    • 2008
  • 본 논문에서는, HCCA로 동작되는 IEEE 802.11e MAC의 Transmission Opportunity (TXOP) 구간을 동적으로 제어함으로서, 무선 Local Area Network (LAN) 환경에서 실시간 멀티미디어 트래픽의 전송 성능을 향상시키는 방식을 제안한다. 프레임의 전송 시기 및 시간을 결정하는 스케줄러의 기존 방식은 무선 단말의 전송률 변화에 상관없이 TXOP 구간을 고정하기 때문에 무선 통신 환경 변화를 동적으로 반영하지 못하는 문제점을 내포하고 있다. 이러한 문제점을 해결하기 위하여 제안방식에서는 무선 단말의 전송률이 낮아지더라도 TXOP 구간이 확대됨으로서, 사용자로부터 발생된 실시간 멀티미디어 트래픽의 전송이 최대한 유지될 수 있도록 한다. 제안방식의 성능 분석을 위해, IEEE 802.11e 참조모델과 함께 NCTUns 시뮬레이터를 이용한 모의실험을 수행하였으며, 그 결과 제안방식은 무선통신 거리 변화에 따른 전송률 변화에도 실시간 멀티미디어 트래픽의 전송이 효과적으로 이루어짐을 확인하였다.

방송 메시지 전달 속도의 통시적 비교에 관한 연구: 라디오뉴스 전달 속도 분석을 중심으로 (A Comparative Study of the Diachronic Change in the Transmission Rate of Broadcast Messages)

  • 박경희
    • 대한음성학회지:말소리
    • /
    • 제64호
    • /
    • pp.15-37
    • /
    • 2007
  • The purpose of this paper is to examine the change of the times on the transmission rate of broadcast message. In order to find out the research results, I collected past recorded news tapes and selected 22 radio news out from era of Japanese Imperialism, 1950's, 1960's and contemporary age. Next I measured each announcer's reading rate, and compared change on news-reading rate between present and past approximately 50 years ago. The results of study with such procedures and methods are as follows : the average reporting rate of newscasters in each era is different. From these results, we can easily grasp diachronic change in the transmission rate of broadcast message. Namely, the results show us that present announcers read news faster than the group of past era of Japanese Imperialism by 68%.

  • PDF

대형 상용차용 수동변속기내 윤활시스템의 유동특성에 관한 연구 (A Study on the Flow Characteristic of Lubrication Oil System in Manual Transmission System for Large Commercial Vehicle)

  • 이중섭;서정세;송철기;신유인;윤지훈;정경택
    • 한국유체기계학회 논문집
    • /
    • 제13권6호
    • /
    • pp.77-82
    • /
    • 2010
  • This study has conducted numerical analysis for lubrication system of transmission for commercial vehicle. The lubrication oil system in transmission can be applied to a large scale commercial vehicle which is over 15tons. The flow rate of lubricating oil has been obtained for each of branch port from the lubrication pipe. The results from numerical simulation are mainly suggested for the mass flow rate of lubrication oil in the rotating main shaft of transmission system. It has been found that the mass flow rate from oil hole increased with an rotating rate of main shaft. The flow characteristic from oil hole has been presented for the lubricating system in the manual transmission.

Seed Transmission of Chrysanthemum stunt viroid in Chrysanthemum

  • Chung, Bong-Nam;Pak, Ha-Seung
    • The Plant Pathology Journal
    • /
    • 제24권1호
    • /
    • pp.31-35
    • /
    • 2008
  • The presence of Chrysanthemum stunt viroid (CSVd) in seed and pollen of diseased chrysanthemum was demonstrated. In seeds infected male parent from crosses in May, CSVd was transmitted to 6.7% of the progeny seedlings, whereas if the female parent was infected, CSVd transmission rate was between 46.9 and 75.7%. A relatively high incidence of 94.4 to 96.0% seed transmission occurred when both parents were infected. In seeds infected male parent from crosses in December, no progeny seedlings were infected with CSVd, whereas if the female parent did, CSVd transmission rate was 1.5%. When both parents were infected, 6.9% seed transmission was occurred. The seed transmission rate depended on the temperature when the crosses were made. CSVd was not detected in the non-infected female parent pollinated with infected pollen but was transmitted to the progenies. This is the first report of seed-borne transmission of CSVd in chrysanthemum.