ATM망에서 ABR서비스를 위한 효율적인 전송률 할당 알고리즘에 관한 연구

천재호,윤상호,김명균,허정석 울산대학교 1999 공학연구논문집 Vol.30 No.2

ATM망에서 ABR 서비스는 CBR, VBR에 할당된 대역폭을 제외한 나머지를 이용해서 데이터를 전송한다. 오디오 또는 비디오 데이터와 같이 실시간 전송이 필요한 서비스들을 전송지연이 제한되는 CBR이나 VBR 트래픽을 이용하여 제공할 수 있지만, 이런 경우에는 전송 대역폭을 효율적으로 사용하지 못하는 단점이 있다. 본 논문에서는 실시간 데이터를 ABR 서비스를 이용하여 효율적으로 전송하기 위한 ABR 대역폭 할당 알고리즘을 제안한다. 제안된 알고리즘은 MCR을 보장하며, MCR에 비례해 전송률을 할당한다. 그리고 접속의 상태를 만족(satisfied)상태와 불만족(bottlenecked)상태로 구분하고, 만족 상태인 접속이 사용하지 않는 대역폭을 불만족 상태인 접속이 사용할 수 있도록 하여 대역폭 활용도를 높인다. 또한 제안된 알고리즘은 큐 제어 함수를 사용해서 큐 길이를 일정한 범위로 유지함으로써 셀의 전송지연을 일정하게 한다. 본 논문에서는 시뮬레이션을 통해 제안된 알고리즘의 성능을 분석하고, 기존에 제안된 ATM 포럼[1]및 Kalampoukas 알고리즘[2]과 비교를 하였다. On ATM networks, ABR services are provided using the remained bandwidth after allocating CBR and VBR traffic. Realtime services such as transmitting audio or video data may be provided using CBR and VBR which have a constrained transmission delay, but in those cases, the communications bandwidth may be wasted. This paper proposes an efficient ABR rate allocation algorithm to transfer real-time data using ABR service. The proposing algorithm guarantees MCR and allocates bandwidth to each connection proportional to its MCR. The proposing algorithm divides the connections in two groups, a satisfied state group and a bottlenecked state group, and enhances bandwidth utilization by allowing the remained bandwidth after allocating to the connections in the satisfied state to the connections in the bottlenecked state. The proposing algorithm uses the queue control function to keep the queue length within some boundary, which makes the transmission delay constant. We simulate and compare the performance of the proposing algorithm with that of the algorithms proposed by ATM Forum[1] and Kalampoukas[2].

주제공원 방문객의 선택행동에 관한 연구

전가환 ; 김상희 김천대학교 2000 김천대학교 논문집 Vol.21 No.-

This study was undertaken because we wanter to present the mar-keting suggestions which make service strategies for the customers. This paper tries to find out major choice attribute on Theme Park when the customer takes a visiting. The study sought to segment users of the theme park and investi-gate their behavioral characteristics. For the purpose of this study, we used the theme park selection attributions as variables of mar-ket segmentation. The sample was the users of Expo Science Park in Taejon. Korea The data for this study were collected from a questionnaire survey 456 visitors.​

대량 출혈을 유발한 공장게실 1예

전정현,이선영,이나란히,신정은,주미순,정성애,한호성,유권 梨花女子大學校 醫科大學 醫科學硏究所 2001 EMJ (Ewha medical journal) Vol.24 No.1

A case of massive intestinal bleeding from jejunal diverticulum is describe. A 62-year-old man was refered to our hospital because of melena and anemia. After admission, he showed massive hematochezia with unstable vital sign. Esophagogastroduodenocopy and colonoscopy, selective abdominal angiography, and RBC bleeding scanning were performed to seek the cause of the intestinal bleeding, but none of these studies revealed the source of bleeding. The examination of small bowel with methylcellulose showed multiple small jejunal diverticuli and a large diverticulum. Resection of the involved portion of jejunum was performed. On pathological examination, two mucosal loss lesions were detected, but ulcer or arteriovenous malformation were not seen in the resected jejunal diverticulum. The patient showed no more intestinal bleeding after operation. Although jejunal diverticuli are rare, the careful search for this complication in a patient with intestinal bleding is important.

VOC와 EC의 공통 속성에 관한 연구

전영호,박성현 弘益大學校 科學基術硏究所 1999 科學技術硏究論文集 Vol.10 No.2

비자의 요구사항은 구체적으로 표현되기 보다는 추상적으로 표현된다는 것이 일반적이다. 따라 소비자의 요구사항을 제품의 설계특성에 직접적으로 연관짓는다는 것은 결코 쉬운 일이 아니다. 연구에서는 제품에 대한 소비자의 요구사항과 설계특성간의 공통요인인 Attribute을 추출 및 활여 양자간의 Relationships Matrix를 구축하는 프로세스를 다루고자 한다. 특히, Relationshipsix는 소비자 요구사항인 VOC, 설계특성인 EC 및 공통요인인 Attribute의 DB를 구축한 후 품질전개(Quality Functin Deployment; QFD)의 핵심인 품질의 집(House of Quality; HOQ)의 형태로 되어 제품 개발의 추후 단계에 활용할 수 있도록 하고자 한다.

유도 전동기를 위한 자기 동조 퍼지 제어기 설계

전광호,하남수,박준열,김상윤 弘益大學校 科學技術硏究所 1998 科學技術硏究論文集 Vol.9 No.2

The conventional PI control, that are used in the control loop for outer speed of the induction motor, also has difficulty dealing with the dynamic speed tracking, parameter variation, and the load disturbance. As a result, the motion control system operates with a poor performance in the motor´s low speed range. In this paper, a novel speed control system that implements the fuzzy logic controller(FLC) is proposed. The proposed FLC used the speed error, its rate of change, and the drive current as three fuzzy variables. The real command output current is chosen by the defuzzification of the fuzzy output extracted from the fuzzy control rules. The flux and the torque of the induction motor are estimated using the dynamic model with an excellent dynamic response over a wide speed range and with the rotor flux field-oriented scheme of the decoupling characteristics. The performance of this control system is substantiated by computer simulations.

다공질 금속재료의 흡음성능 평가

전종균,엄호성 선문대학교 중소기업기술지원연구소 2001 선문공대 연구/기술 논문집 Vol.6 No.1

소음이란 공기의 진동에 의한 음파중에서 가청적인 것으로서 인간이 감각적으로 바람직하지 않다고 느껴지는 소리이다. 이러한 소음저감을 위해 사용되는 물질중 하나가 다공질 금속 재료이며, 이것은 에너지 흡수재로 많이 사용되고 있는 균일한 셀(cell)형태 구조의 기공을 가진 물질이다. 고체 소재와는 다른 다양한 물질의 특성으로 인하여 매우 특별하면서도 다양한 용도로 사용되고 있다. 본 논문에서는 다공질 금속 재료를 이용한 흡음재를 연구하였다. 압축기(compressor)에서 나오는 공기의 압력을 오피리스(orifice)에서 단계적으로 조절하고, 시험편과 마이크로폰을 적절히 배치하여 주파수 분석기로 흡음성능을 확인하였다. Noise generated by the vibration of air in the range of hearing frequencies is undesirable for human sense. The porous metal is one of the sound absorbing materials and in structure it has homogeneous cell in which the energy would be dissipated throughout. Since it also has various material characteristics compared with solid materials, it could be used for specific purpose. In this paper, sound absorbing material has been investigated by using the porous material. The efficiency for sound absorbing materials by frequency analyzer has been verified by the experiments in which the air pressure from the compressor is controlled step by step at the orifice and specimen and microphone are arranged accordingly.

선택적 레이저 소결법을 이용한 기어박스의 정밀주조기술 개발

최상련,김천기,박근,오철호 韓國工作機械學會 2000 한국생산제조학회지 Vol.9 No.1

In this paper, rapid prototyping and precision castiong technology have been devloped for the manufacturing of inlet pear box of an airplane. Rapid prototyping is a new prototyping technology that produces complicated parts directly from threedimensional CAD data with a high efficiency, and has been extensively applied to various manufacturing processes. In the present work, Selective Laser Sintering(SLS) system is untilized in order to manufature prototype of the inlet gear box. Prototyping technology using SLS is also investigated from the viewpoint of accuracy. Using the SLS master, the casting products are manufactured through several processes such as: vacuum casting, lost wax shell casting and investment cast-ing. The shrinkage characteristics of wax and cast iron in the casting procedures are considered, and then reflected to the design procedure so that the accuracy of the product in improved consequently.

단전호흡수련이 다트던지기 과제의 수행에 미치는 영향

조춘호,박진성 한국스포츠리서치 2001 한국 스포츠 리서치 Vol.12 No.4

The purpose of this study was to analyze the effects of Dan-jeon breathing training on dart-throwing performance. Subjects were 24 junior high school students in 9th grades, who were randomly divided into 3 groups, i.e. Imagery group (8 males). Dan-jeon breathing group(8 males), Control group(8 males). Data obtained from all subjects in three acquisition and retention trials blocks were analyzed. Analysis performed on the acquisition trials were a 3 x 3(condition x trial block) analysis of variance(ANOVA)with repeated measures on the second factor. The retention trials were analyzed in a 3 X 3(condition x trial block) analysis of variance(ANOVA)with repeated measures on the second factor. Dependent variables were absolute error(AE), variable error(VE). The conclusions are as follows: 1. The absolute error in the acquisition phase and retention phase revealed that imagery group and Dan-jeon breathing group performed significantly better accuracy than the control group. 2. The variable error in the acquisition phase and retention phase showed that imagery group and Dan-jeon breathing group performed significantly better than the control group. 3. There was significant interaction effects in the absolute, variable error during the acquisition phase. However, there was no significant interaction effects in the absolute, variable error during the retention phase.

三天地의 環境과 生物多樣性 : I. Enviornmental Factors and Flora I. 環境要因과 植物相에 關하여

신상천,이종운,배규호,전재인,강경화 嶺南大學校 基礎科學硏究所 1992 基礎科學硏究 Vol.12 No.-

Environmental factors and phytological aspects of Samchunimpoundment in Kyongsan, Kyongpook were studied. 40 quadrats in 4 sites had 94% herbaceous cover, 31% shrub cover and 18% tree cover. Ambrosia artemisiifolia var. elatior, Metaplexis japonica, Erigeron annuus, Humulus Japonicus, Eragrostis ferruginea, Artemisia princeps var. orientalis were dominant herbaceous species and found cultivated plants of Hordeumn vulgare var. hexastichon, Prunus persica, Morus alba and neophytes of Ambrosia artemisiifolia var. elatior, Erigeron canadensis, Erigeron annuus, Ailanthus altissima, Bidens bipinnata, Lactuca indica var. laciniata, Robinia pseudo-acacia, oenothera odorata, Euphobia maculata. The investigated sites were divided into 4 patterns based on the vegetation with high difference level and Ambrosia artemisiifolia var. elatior, Medicago sativa, Setaria viridis, Metaplexis japonica, Humulus japonicus, Calystegia japonica, Forsythia koreana, Lsctuca indica var. laciniata were different species group. More than 90% on the surface area of water mass covered with Nelumbo nucifera, Marsilea quadrifolia and Typha angustata and distributed Hydrilla verticillata, Ceratophyllum demersum, Trypa pseudo-incisa, Myriophyllum spicatum under water. Average data of environmental factor analysis are as followings; air temperature 25.8℃, ph 6.77, total hardness 117.94㎎/ℓ, SS 4.5㎎/ℓ,Do 3.3㎎/ℓ,BOD 6.6㎎/ℓ,COD 7.2㎎/ℓ,cl- 17.56㎎/ℓ,?? 7.14㎎/ℓ,Mn 0.05㎎/ℓ, Zn 0.04㎎/ℓ. Total quality of impoundment water were heavily polluted and were quality class Ⅳ.

테니스 클럽활동이 전업주부의 신체적 자기효능감에 미치는 효과

박진성,조춘호 한국스포츠리서치 2001 한국 스포츠 리서치 Vol.12 No.4

The purpose of this study was to investigate the effects of effects of tennis club activities on physical self-efficacy in housewives. Subjects were 51 housewives who were randomly divided into experimental group(25males), control group(26males). The subjects of Experimental group performed tennis practice activity during 8weeks, three-times a week and 90minutes a day. A 2 x 3(groups x times) analysis of variance with repeated measurement was computed for physical self-efficacy in tennis club activity. The level of significancy of all hypothesis tests was α=.05. The conclusions were as follows ; 1. There was significant difference between experimental group and control group on the perceived physical ability scale. 2. There was significant difference between experimental group and control group on the physical self-presentation confidence scale. 3. There was significant difference between experimental group and control group on the physical self-efficacy scale. 4. There was interaction effect between groups and times on the physical self-efficacy scale, perceived physical ability scale, physical self-presentation confidence scale.