ATM망에서 실시간 연결수락제어에 관한 연구

장혁,김영훈,김용수,김희철,나상동 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1

본 논문은 이질적 버스트 트래픽을 갖는 ATM(Asynchronous Transfer Mode) 망에서 실시간 연결 수락 제어를 위한 유체 흐름 모델(fluid flow model)에 기반을 둔 실시간 알고리즘을 제안한다. 셀 손실 확률은 QOS(Quality of Service)의 기준이 되므로 제안된 실시간 알고리즘은 일정한 메모리 크기와 연결 요청의 수락 여부 즉, 연결 수락 여부의 결정을 위한 하나의 영역을 필요로 한다. 이러한 트래픽 소스 각 타입에 대한 셀 손실 확률은 트래픽 소스 타입 전체에 하나만 존재하더라도 요구를 충족 시킬 수 없으므로, 본 논문에서 제안된 실시간 알고리즘에 의해 산출되는 각각의 셀 손실확률에 충분한 상한선을 제공하는 전형적 트래픽 매개변수를 사용하여 성능을 분석한다.

축산시설에서 발생되는 악취의 축종별 특성에 대한 설문조사

장영기,송기봉,김호정,유용희 한국환경영향평가학회 2004 환경영향평가 Vol.13 No.1

At Recent the number of livestock is rapidly increased and the scale of farm has changed to large operations in Korea. So the odors frcm livestock feeding operations have increased and become major environmental problem. The odor emission are dependent on the types of manure management system and the meteorological factors. This report presents the results of a questionnaire on the odor characteristics from livestock facilities for the beef, dairy, swine and poultry. It is founded that the impact by odors from the facilities for swine and poultry is higher than cow and dairy, and the odor intensity at morning is higher than other times.

요추부 경막외 스테로이드 주사에서 경추궁(經椎弓)법과경추간공(經椎間孔)법의 효과

김희상,홍장혁,안경회,김용걸 大韓再活醫學會 2000 Annals of Rehabilitation Medicine Vol.24 No.4

단독주택의 에너지효율 등급설정 및 인증기준(안) 연구

장용성,홍성희,박효순,서승직 대한건축학회 2004 대한건축학회논문집 Vol.20 No.12

This study aimed to make out certification criterion and establishment of the energy efficiency rating of a detached house To this end, we surveyed the energy consumption and plan type of a existing detached house And we also set a reference house throughout a investigation data and developed simple energy analysis software program for a energy performance evaluation of a detached house A energy efficiency rating of a detached house was established by a comparison and analysis of heating energy simulation result according to variation of the U-value of a window and construction, ratio of a window area, setting temperature of a room and air change of rate

와인 잔 형태 슬롯-패치 UWB 안테나의 설계

장준원,황희용 강원대학교 정보통신연구소 2008 정보통신논문지 Vol.12 No.-

In this pafer, we proposed a wineglass slot-patch UWB antenna using approximately symmetry plane for prototype antenna of circular-slot UWB antenna. Using on field patterns, we show that the prototype circulat-slot UWB antenna operates on a series of multi-pole radiation based on TEn modes and the first resonant frequency by designed prototype antenna slot size. Ee designed and fabricated the wineglass slot-patch UWB antenna on FR4 substrate with t=1.524mm, εr=4.4 and tanδ=0.025, which not only has the half size of the original but also maintains UWB characteristics. The measured gain is reduced a little however radiation patterns are similar to that of the prototype antenna and maintain identical direction of max gain for all operation frequency.

초광대역 원형 슬롯 패치 안테나의 최적 설계

장준원,최경,황희용 강원대학교 정보통신연구소 2007 정보통신논문지 Vol.11 No.-

In this paper, an ultra wideband(UWB) circular slot antenna fed by tapered microstrip line is presented. The designed antenna is composed of a tapered feed line, a circular slot and a circular patch. Important physical parameters concerned with the wideband characteristic are investigated and optimized. The operational bandwidth of the antenna is from 3.5 GHz to 13.8 GHz. The simulated and the measured data show good agreement each other.

타원 패치-슬롯형 UWB 안테나의 해석

장준원,최경,황희용 江原大學校 産業技術硏究所 2007 産業技術硏究 Vol.27 No.B

In this paper, an modal analysis based on the distribution of the electromagnetic fields on the UWB elliptical patch-slot antenna is presented. We designed the UWB antenna by iterating the dimensional parameters of the antenna as the traditional design method. Then the antenna was carefully analyzed using 3D E-M simulator. The result of the analysis shows that the slot antenna operates on a series of the multi-pole radiations based on TE modes matched to the system impedance. This result gives us an easier method to design the similar antennas, which is the impedance matching to the system impedance after once constructing a proper structure with a series of multi-mode resonances.

컴퓨터 모의실험을 이용한 Stop-and-wait ARQ 기법 성능 평가

이용학,이호준,최길용,장재신 인제대학교 2012 仁濟論叢 Vol.27 No.1

ARQ schemes are commonly used in various communication areas, for instance TCP protocol, to combat communication packet errors and there are three different types of ARQ protocol. In this paper, the performance of stop-and-wait ARQ scheme is evaluated with computer simulation and then compared with analytical results. Two different traffic generation modes are considered: the first one is the saturated traffic model and the other one is periodic arrival model based on exponential distribution. For performance measures, link utilization and average packet delay are used in this paper. According to numerical results, it is known that performance results from computer simulations coincide well with those by mathematical analysis. For the further study, we will continue to carry performance evaluations of two other ARQ schemes, go-back-N ARQ and selective repeat ARQ schemes.

계분 발효사료의 급여가 거세한우의 도체형질에 미치는 영향

정장용,홍병희 진주산업대학교 농업기술연구소 2006 農業技術硏究所報 Vol.19 No.-

본 시험은 한우비육우의 발효사료 급여효과를 구명하기 위하여 발효사료 급여수준에 따라 4 처리구 (대조구 : 100% 농후사료, T1 : 75% 농후사료 + 25% 발효사료, T2 : 50% 농후사료 + 50% 발효사료 및 T3 : 25% 농후사료 + 75% 발효사료)를 공시하였으며, 거세한우의 경제성을 분석하기 위하여 평균체중 294 ㎏ 되는 한우거세우 (♂)을 총 28두를 임의 배치하여 14개월령부터 29개월령까지 총 16개월간 사양시험을 실시한 결과를 요약하면 다음과 같다. 1. 도체조사 결과, 도체중과 정육율은 타처리구에 비하여 T2구에서 낮았으나 배최장근단면적은 T2 및 T3구에서 넓었으며, 등지방두께는 T3구에서 두꺼웠으며, 육량지수는 처리구간에 유의차가 인정되지 않았다. 육량등급은 T3구에서 A등급에 가장 많았으며, 육색, 지방색, 조직감 및 성숙도는 처리구간에 차이가 없었다. 육질등급은 타처리구에 비하여 T1구에서 1+등급에 가장 많아 육질이 상당히 우수한 것으로 나타났다. 2. 경제성 분석결과, 비육전기에서 ㎏당 증체에 소요되는 사료비는 대조구에 비하여 계분 발효사료 첨가구인 T1, T2 및 T3구가 현저히 낮았으며, 비육중기 및 후기에도 같은 경향을 나타내고 있다. 비육전기간 동안에도 ㎏당 증체에 소요되는 사료비가 대조구 (3,575원)에 비하여 T1, T2 및 T3구가 각각 3,237, 3,112, 2,913원으로서 발효사료 급여수준에 증가할수록 사료비 절감효과가 크게 나타나 농후사료를 25%를 발효사료로 대체급여한 경우 9%, 50% 대체 급여한 경우 17%, 75% 대체급여한 경우 19%의 사료비 절감효과가 있었다. 이상의 결과를 종합해보면 농후사료의 25%를 계분사료를 반추가축에 급여할 경우 적정 급여수준은 25~50% 정도일 것으로 사료된다. 발효사료로 대체할 경우 총증체량 및 일당증체량, 및 사료섭취량면에서 우수하였으며, ㎏당 증체에 소요되는 사료비는 계분 발효사료 첨가수준이 증가할수록 증가되었다. 육량등급은 계분 발효사료를 50%첨가한 구에서 높았으며, 육질등급은 게분 25% 첨가구에서 높게 나타났다. 따라서 농후사료 대체로서 계분 발효사료를 반추가축에 급여할 경우 적정 급여수준은 25~50% 정도일 것으로 사료된다. This study was conducted to investigate the effect of fermented cage layer manure diet on carcass characteristics in Hanwoo steers. Feeding trial consisted of four treatment groups; control (100% concentrate), T1 (75% concentrate + 25% fermented cage layer manure), T2 (50% concentrate + 50% fermented cage layer manure) and T3 (25% concentrate + 75% fermented cage layer manure). Total 28 Hanwoo steers (average body weight, 294 ㎏) aged 14 months were reared for 16 months until 29 months old to determine body weight gain, feed intake, feed economics, meat quantity and quality. The results obtained were summarized as follows; 1. Carcass weight and dressing percent were lower (P<0.05) in T2 than in any other groups and longissmus dorsi area was larger in T2 and T3 than in control and T1. However, yield index was not significantly different among the treatments. Yield grade was higher in T3 than in any other groups, but marbling score, meat color, firmness and maturity were not significantly different among treatments. The 1+ grade for meat quality was higher in T1 than in any other groups. 2. Feed cost per 1 kg body weight gains during finisherⅠ, Ⅱ and Ⅲ period was lower in T1, T2 and T3 than that in control. Feed cost per 1 kg body weight gain during whole period was 3,575, 3,237, 3,112 and 2,913 won in control, T1, T2 and T3, respectively. The expense in T1, T2 and T3 groups were lower by about 9, 17 and 19% of the feed cost compared with control group. With respect to economic analysis of Hanwoo production, the groups fed cage layer manure diet except T2 resulted in a lower beef production cost.

이중구조 촉매전극을 이용한 알칼리 연료전지에 관한 연구

노용우,이태희,설용건,장의종,김경림 연세대학교 산업기술연구소 1990 논문집 Vol.22 No.1

An experimental low-temperature low-pressure hydrogen-oxygen alkali fuel cell was constructed and its performance was tested for various operating conditions. Hydrogen was used for fuel and oxygen was used for oxidant and KOH solution was used for electrolyte. Both electrodes for hydrogen and oxygen were prepared by the same method and the materials used were carbonyl nickel and ammonium bicarbonate. Experimental results show that maximum current density of 8.91 mA/㎠ was obtained at 40℃ wt% KOH solution and optimum power was 1.74 mW/㎠ at 6.43 mA/㎠ current density.