• 한국컴퓨터산업학회논문지
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• 제2권9호
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• pp.1155-1162
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• 2001

본 논문은 UNIX 시스템의 최적 이용률(Optimal Utilization)을 결정하는 방법을 제시한다. 제시된 방법은 사용자가 인내할 수 있는 응답시간(Tolerable Response Time)을 제공하는 범위에서 사용자에게 허용될 수 있는 최대 이용률이 최적 이용률이 된다는 정의(Definition)를 근거로 하여 개발되었다. 인내할 수 있는 응답시간이 길어지면 최적 이용률도 높아지므로 최적 이용률은 인내할 수 있는 응답시간의 최대값에서 구해진다. 인내할 수 있는 응답시간은 서비스 목표(Service Objective)가 주어지면 도출해 낼 수 있다. 본 논문에서는 인내할 수 있는 응답시간이 0.24초라는 것과 최적 이용률의 세 가지 구성요소는 %wio, %sys, %usr 이라는 것을 보여준다. 또한 최적 이용률을 결정하는 실제의 과정을 예시하기 위하여 UNIX 운영체제를 사용하는 IBM 컴퓨터의 최적 이용률을 구하는 과정을 예시한다.

• 한국정보처리학회논문지
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• 제2권5호
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• pp.807-813
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• 1995

본 논문은 UNIX 시스템의 최적 이용율(Optimal Utilization)을 결정하는 방법을 제시한다. 제시된 방법은 사용자가 인내할 수 있는 응답시간(Tolerable Response Time) 을 제공하는 범위에서 사용자에게 허용될 수 있는 최대 이용율이 최적 이용율이 된다 는 정의(Definition)를 근거로하여 개발되었다. 인내할 수 있는 응답시간이 길어지면 최적 이용율도 높아지므로 최적 이용율은 인내할 수 있는 응답시간의 최대값에서 구해 진다. 인내할 수 있는 응답시간은 서비스 목표(Service Objective) 가 주어지면 도출 해낼 수 있다. 본 논문에서는 인내할 수 있는 응답시간이 0.24초라는 것과 최적 이용 율의 세가지 구성요소는 %wio, %sys, %usr이라는 것을 보여준다. 또한 최적 이용율을 결정하는 실제의 과정을 예시하기 위하여 UNIX 운영체제를 사용하는 IBM 3081 컴퓨터 의 최적 이용율을 구하는 과정을 보여준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.72-75
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• 2004

In this paper, the task assignment strategy considering communication delay and the priority of distributed tasks is proposed for the real-time network system in order to maximize the utilization of the system. For the task assignment strategy, the relationship among priority of tasks in network nodes, the calculation time of each task, and the end-to-end response time including the network delay is formulated firstly. Then, the task assignment strategy using the genetic algorithm is proposed to optimize the utilization of the system considering the LCM(Least Common Multiple) period. The effectiveness of proposed strategy is proven by the simulation for estimating the performance such as the utilization and the response time of the system in case of changing the number of tasks and the number of network nodes.

• Asian-Australasian Journal of Animal Sciences
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• 제16권6호
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• pp.863-866
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• 2003

This study was conducted to examine the effects of dietary cellulose levels on growth, nitrogen utilization, the retention time of diets in the digestive tract, and caecal microflora of 2-month-old Single Comb White Leghorn male chickens fed 3 purified diets that contained 0, 3.5% and 10% cellulose in equal amount of nutrients for 7 days. Body weight gain and nitrogen utilization were significantly higher (p<0.05), while total microflora counts in the caecal contents and retention time of the diet in the digestive tract were significantly lower (p<0.05) in the group fed 3.5% dietary cellulose compared with the group fed 10% dietary cellulose. Body weight gain, nitrogen utilization and retention time of the diet in the digestive tract decreased significantly while the total microflora count in the caecal contents increased significantly in the group fed 10% dietary cellulose compared to the group fed 0% dietary cellulose (p<0.05). Chickens fed 10% dietary cellulose had significantly increased counts of uric acid-degradative bacteria such as Peptococcaceae and Eubacterium, including Peptostreptococcus (p<0.05). The results suggest that cellulose in purified diets is an effective ingredient and the effects on growth, nitrogen utilization, caecal microflora counts and diet retention time in the digestive tract are dependent on the inclusion rate. Positive or negative effects of dietary cellulose are displayed by growth, nitrogen utilization, caecal microflora counts and retention time of the diet in the digestive tract. Positive effects were displayed when the inclusion rate is 3.5% and negative effects were displayed when that is greater than 3.5% of the diet, and the phenomenon is without reference to the age of the chickens.

• Journal of Preventive Medicine and Public Health
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• 제23권3호
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• pp.316-323
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• 1990

To analyze of determinants influencing the utilization of the rural health sub-centers (HSCs), 116 of 144 HSCs in Kyong Gi Do, were selected for this study. The self-administered questionnaire covering the environment and the characteristics of doctors working in the HSCs was sent to HSCs by mail. 105 questionnaires were returned of which 88 were completed and use in the study. The dependant variable was the total number of medical care visits to the HSCs from January 1, 1990 to March 31, 1990. Data was analyzed by multiple regression analysis. The results were as follows : First, the more time required to set from the HSCs to nearest hospital or clinic, the higher the utilization of the HSCs. Second, the more geographically accessible the HSCs was, the more utilization the HSCs. Third, the older of the HSCs doctors were, the more utilization of the HSCs. Fourth, the higher frequency of bus service from the HSCs to town, the more utilization of the HSCs. Fifth, the more time required from the HSCs to town, the more utilization of the HSCs. Therefore, the determinants influencing the utilization of the rural HSCs in Kyong-Gi Do, are mostly geographical accessibility of medical care.

• International Journal of Control, Automation, and Systems
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• 제4권5호
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• pp.601-614
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• 2006

In this paper, a study on task assignment strategies for a complex real-time network system is presented. Firstly, two task assignment strategies are proposed to improve previous strategies. The proposed strategies assign tasks with meeting end-to-end real-time constraints, and also with optimizing system utilization through period modulation of the tasks. Consequently, the strategies aim at the optimizationto optimize of system performance with while still meeting real-time constraints. The proposed task assignment strategies are devised using the genetic algorithmswith heuristic real-time constraints in the generation of new populations. The strategies are differentiated by the optimization method of the two objectives-meeting end-to-end real-time constraints and optimizing system utilization: the first one has sequential genetic algorithm routines for the objectives, and the second one has one multiple objective genetic algorithm routine to find a Pareto solution. Secondly, the performances of the proposed strategies and a well-known existing task assignment strategy using the BnB(Branch and Bound) optimization are compared with one other through some simulation tests. Through the comparison of the simulation results, the most adequate task assignment strategies are proposed for some as system requirements-: the optimization of system utilization, the maximization of running tasktasks, and the minimization of the number of network node nodesnumber for a network system.

• Journal of Preventive Medicine and Public Health
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• 제23권2호
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• pp.185-193
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• 1990

The purpose of this study is to observe the pattern of change in medical care utilization over time in early years of insurance coverage. The source of data is the benefit records file of a voluntary medical insurance society for covering the four-year period, from 1982 to 1985. The measure of medical care utilization used in this study is the age-sex standardized percentage of the enrollee who have visited a physician over total analytical population during a three-month period. For six cohorts by the year of enrollment ($1979{\sim}1984$), the relationship between the utilization and duration of insurance coverage was examined controlling for the calender year and season. In the analysis, logistic multiple regression and residual analysis were employed. It was observed that medical care utilization rapidly increased during the early stage of insurance coverage, and after then increased at a slower rate over time to become almost stable in about twenty months.

• 한국철도학회논문집
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• 제15권6호
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• pp.638-644
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• 2012

본 연구에서 일반철도의 선로이용율의 범위인 60%를 검토하여, 이용가능한 시간과 이용 불가능한 시간을 수치화 하였다. 또한 선로이용율을 변화시키는 요소인 선로유지보수시간에 대한 계산과 적정한 추정시간을 분석하였다. 적절한 철도운영계획과 원활한 시설유지보수를 통한 열차의 안전을 보장하여야 한다. 동시에 매일 연속되는 열차Dia의 원상회복력도 운영계획에 반영되어야 한다. 이런 사항들을 고려하여 보유 중인 기계장비와 국가철도망에 대한 자료를 활용하여 유지보수작업시간 산출방법을 개선하고, 열차지연에 대비한 여유시간을 확보하도록 검토하였다. 결론적으로 일반철도의 선로이용율과 선로유지보수시간 구성요소를 함께 수량화하여, 선로이용율은 60% 내외가 타당함을 증명하였다.

• Nuclear Engineering and Technology
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• 제54권2호
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• pp.501-506
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• 2022

Long turn-off time limits high frequency operation of Bipolar Junction Transistors (BJTs). Turn-off time decreases with increases in the recombination rate of minority carriers at switching transients. Fast neutron irradiation on a Si BJT incurs lattice damages owing to the displacement of silicon atoms. The lattice damages increase the recombination rate of injected holes with electrons, and decrease the hole lifetime in the base region of pnp Si BJT. Fast neutrons generated from a beryllium target with 30 MeV protons by an MC-50 cyclotron were irradiated onto pnp Si BJTs in experiment. The experimental results show that the turn-off time, including the storage time and fall time, decreases with increases in fast neutron fluence. Additionally, it is confirmed that the base current increases, and the collector current and base-to-collector current amplification ratio decrease due to fast neutron irradiation.

• 인터넷정보학회논문지
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• 제6권2호
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• pp.25-35
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• 2005

실시간 스케줄링 알고리즘에서는 비율단조(RM) 스케줄링 알고리즘과 마감시한(EDF) 스케줄링 알고리즘이 가장 일반적으로 사용되고 있다. 이러한 알고리즘에서는 태스크 집합의 전체 이용율 값을 가지고 수행 가능성을 판별하였다. 그러나 임의의 태스크에서 이용율 값이 초과되면 개별 태스크의 한계성을 전혀 예측할 수 없는 문제점이 있었다. 본 논문에서 제안한 알고리즘은 이용율 값이 초과한 태스크를 예측하고, 개별 태스크의 이용율 값을 기반으로 스케줄링 가능성 여부를 판단하는 방법을 제시하였다. 또한, 실시간 시스템에서 스케줄링 가능성 검사의 한계성을 시뮬레이션을 통해 예측하고 결과를 분석하였다.