• 대한전자공학회논문지TC
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• 제45권12호
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• pp.13-19
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• 2008

본 논문에서는 4개의 송신 안테나를 사용하는 새로운 폐루프 직교 시공간 블록 부호 (Closed Loop Orthogonal Space-Time Block Code) 기법을 제안하고 기존의 폐루프 기법들과 비트오율 (Bit Error Rate; BER) 성능을 비교한다. 제안된 기법은 송신기에서 폐루프 기법을 통하여 채널 정보를 귀환받고 심벌 결합기를 통해 변조 심벌들을 결합한 후 시공간 블록 부호화하여 송신 안테나로 전송한다. 그 결과, 제안된 기법은 기존의 폐루프 시공간 블록 부호 기법에 비해 귀환된 채널 정보를 보다 효율적으로 이용함으로써 최대의 채널 이득을 획득하는 동시에 full-rate을 만족한다. 또한 채널 행렬이 직교하므로 수신 심벌에 대한 선형적인 복호가 가능하며 수신기는 낮은 복호 복잡도를 갖게 된다. 모의실험 결과, 제안된 기법은 기존의 폐루프 기법들과 비교하여 성능 향상을 보임을 알 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.244-249
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• 1998

In this paper, the hybrid state space self-tuning control technique Is studied within the framework of fuzzy systems and dual-rate sampling control theory. We show that fuzzy modeling techniques can be used to formulate chaotic dynamical systems. Then, we develop the hybrid state space self-tuning fuzzy control techniques with dual-rate sampling for digital control of chaotic systems. An equivalent fast-rate discrete-time state-space model of the continuous-time system is constructed by using fuzzy inference systems. To obtain the continuous-time optimal state feedback gains, the constructed discrete-time fuzzy system is converted into a continuous-time system. The developed optimal continuous-time control law is then convened into an equivalent slow-rate digital control law using the proposed digital redesign method. The proposed technique enables us to systematically and effective]y carry out framework for modeling and control of chaotic systems. The proposed method has been successfully applied for controlling the chaotic trajectories of Chua's circuit.

• 한국병원경영학회지
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• 제4권1호
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• pp.41-65
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• 1999

This study was attempted to identify the factors affecting profitability of general hospital in Kyung-In Region. Operating profit to gross revenues and net profit to gross revenues were used as a proxy indicator for profitability of hospitals. The unit of analysis was hospital, and the data were collected 5 years data from 20 hospitals. The major findings are as follows; (1) The average operating profit rate was 1.03% and the net profit rate was -5.00% in twenty hospitals in the Kyung-In Region for the last five years. In terms of maximum surplus, the operating profit rate was 14% and net profit rate was 3.40%. In terms of maximum loss revenue, the operating profit rate was -16.56% and the net profit rate was -22.83%. (2) Since the year 1993, which was the starting year of this study, the operating profits and the net profits consistently decreased. (3) Analyzing the difference in profits among various hospital groups, the tertiary hospital group and the 501-1000 beds group exhibited the highest in operating profit rate. Also, among the higher grade number of beds in hospital group, per 100 beds group, the 41-50 beds group exhibited the highest in operating profit rate. There is a statistically significant difference in those groups(p<0.05, p<0.01). (4) In the health care delivery system, the profit gain in the secondary hospital was 51.5% and in the tertiary hospital was 72.4%. Based on the number of beds in each hospital group, the highest profit gain was 75.0% in the over 1001 beds group, and 71.4% in the 501-1000 beds group. Also, among the higher grade number of beds in hospital group, per 100 beds group, the 41-50 beds group exhibited 88.6% surplus. (5) According to the surplus difference based on the analysis of health care utilization, a group with over 31 patients in bed turnover rate, a group with over 96% in bed occupancy rate and group with over 9% in emergency cases to outpatient visits exhibited the highest profit gains. In addition, a group with over 301 patients in daily outpatient visits per 100 beds and group with 11-12 days average length of stay exhibited the highest profit gains. These results are statistically significant(p<0.05, p<0.01). (6) According to a stepwise regression analysis, the variables measuring the bed turnover rate, number of licensed beds, and number of outpatient visits per specialist explain 34.1% of the variation in operating profits. In terms of net profits, the new outpatient visits, the bed turnover rates and the number of general bed variables explain 30.6%. These results are statistically significant(p<0.01).

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권3호
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• pp.425-445
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• 2013

The IEEE 802.11 compliant stations can transmit at multiple transmission rates. Selection of an appropriate transmission rate plays a significant role in determining the overall efficiency of a communication system. The technique which determines the channel state information and accordingly selects an appropriate transmission rate is called rate-adaptation protocol. The IEEE 802.11 standard does not provide standard specification for implementing a rate-adaptation protocol for its multi-rate capable wireless stations. Due to the lack of standard specification, there is a myriad of rate-adaptation protocols, proposed by industry and various research institutes. This paper surveys the existing rate-adaptation schemes, discusses various features which contribute significantly in the process of rate-adaptation, the timing constraints on such schemes, and the performance gains in terms of throughput, delay and energy efficiency; which can be gained by the use of rate-adaptation. The paper also discusses the implication of rate-adaptation schemes on the performance of overall communication and identifies existing research challenges in the design of rate-adaptation schemes.

• 대한기계학회논문집
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• 제14권5호
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• pp.1112-1118
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• 1990

본 연구에서는 선단의 각속도를 측정하여 궤환함으로써 유연한 로봇팔의 진동 을 억제함과 동시에 선단의 위치를 제어하고자 한다. 선단에 레이트 자이로를 설치 하여 선단의 각속도를 측정하였다. 레이트 자이로는 이미 비행체의 제어에 널리 사 용되고 있는 정밀 각속도 센서로 소형이면서 가벼워 회전 진동측정이 매우 쉽고 편리 한 장점이 있다. 또한 유연한 로봇팔을 선단에 집중질량이 있는 오일러보로 가정하 여 모델링을 하였으며, 실험에서는 1차진동 모드까지만 고려하였다.

• 대한수의학회지
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• 제10권1호
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• pp.1-4
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• 1970

Experiments were carried out in order to study the relationship of thyroid activity to growth potentiality in chicken. Further work was also performed to determine thyroid secretion rate and body gain of the different sexes. A correlation coefficient of 0.241 in the male and 0.237 in the female were obtained between daily gains and daily thyroid $^{131}I$ out put rate in the chicken. The correlation was not statistically significant, but the chicken with a lower thyroid activity tended to gain faster than those with a higher thyroid activity. The average daily gain of the female(12.13 gram) was significantly higher than the male (9.28 gram). The average daily thyroid secretion rate of male tended to have a higher rate, but it was not statistically significant.

• 대한가정학회지
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• 제8권1호
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• pp.124-145
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• 1970

The author carried out this study to research the biological value of the protein fermented wheat bran. This study mainly devided into two parts. First part includes seven subgroups composed of five rats and second part fourteen subgroups composed of six rats each. In the first part of this study forty weanling male rats, aged 40${\pm}$5 days were fed by fermented wheat bran diet for seven weeks. In second part of this study 90 male weanling rats were fed by rice and soybean diet supplemented by fermented wheat bran. In the first part of this study food consumption rate of fermented group showed higher than standard group but the former group is lower than the later in the body weight gains. In the second part of this study, rice groups showed same trend of the result of the first part, but soybean groups did not go along with the result of rice group. In regard to body nitrogen retention rate, fermented wheat diet group showed higher than the standard group in the first part of this study. In the second part of this study rice diet groups revealed same result as that of the first part of this study but soybean diet did not give the same result in this respect. There was no significant difference in organ weight in all experimental groups but devided by 100 gram of body weight, the reverse is true in compare with body weight gains. Hematological investigation did not show the significance in both experimental and standard groups of the first and the second studies. It is conclusion of this study that rice which is inferior to soybean in protein quality, increases the rate of supplementary effect by fermented wheat bran in all respects of this study.

• 한국통신학회논문지
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• 제33권1A호
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• pp.36-43
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• 2008

본 논문에서는 디코딩 후 전달 시스템을 위한 최적의 중계노드 선택방법을 제안한다. 그 최적의 중계노드 선택 방법은 디코딩 후 전달 시스템에서 신호 중계를 위해 사용되는 시간슬롯을 최소화하고 최종 신호 대 잡음비를 최대화한다. 그러나, 중계노드 선택을 위한 시스템의 오버 헤드가 요구된다. 독립적이고 동일한 레일레이 분포를 따르는 채널들을 가정하여, 제안된 최적의 중계노드 선택방법 기반의 디코딩 후 전달방식에 대한 용량 저하 확률과 평균 비트 오차율의 식들을 유도하고, 그 식들의 수치적 결과와 시뮬레이션 결과를 비교하여 수식들을 검증한다. 중계노드의 개수가 각각 2, 4, 8이고 오버 헤드에 대한 시간슬롯의 개수가 각각 1, 2, 4일 때, 제안된 방식은 기존의 디코딩 후 전달방식보다 1% 비트 오차율에서 각각 1 dB, 2 dB, 3 dB의 이득이 있고, 1 bps/Hz에 대한 1% 용량 저하 확률에서 각각 0.5 dB, 4 dB, 12 dB의 이득이 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제5권2호
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• pp.261-266
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• 1992

Yearling replacement heifers were used in a two-year study at the Fort Stanton Experimental Ranch near Capitan, New Mexico, USA to compare frequency (once versus three times weekly) of feeding a cottonseed cake supplement. The study involved periods of 130 days (January 4 through May 14) in 1985, and 146 days (December 4 through April 29) in 1986. In each year, supplemental periods were just before the breeding season (natural breeding in multiple-sire groups) that lasted for 75 days during first year and 60 days during second year. During the first year, all (83) heifers (Angus $\times$ Hereford) were supplemented at a level equivalent to 45 kg/head daily and during second year, all (69) heifers (Angus $\times$ Hereford, Hereford) were fed at a level equivalent to .68 kg/head daily. In the first year, heifers were sorted by initial weight into two replications, i.e., those weighing under 223 kg were placed in replicate 1 and those weighing over 223 kg were placed in replicate 2. During the second year, heifers were sorted by breed into two replications, i.e., Angus $\times$ Hereford heifers were placed in replicate 1 and Hereford heifers in replicate 2. Each year, half of the heifers in each replication were supplemented once weekly and the other half three time weekly. Weight gains of heifers were similar for the two treatments over both years of study. During the first year, weight gains for heifers supplemented once or thrice weekly (.23 vs .21 kg daily, respectively) did not differ (p>.05) and the same trend for the second year (.15 vs .16 kg daily, respectively) was observed. Similarly, breeding performance was consistent with weight gains and no difference (p>.05) between treatments was observed either year. Lower conception rates during the second tear of study (92 vs 72% for years 1 and 2, respectively) were due mainly to involvement of Hereford heifers that had an average weight of 232 kg at the start of breeding season and conception rate of 54% (averaged across both supplemental treatments). Based on the combined results of both trials, frequency of supplementation did not affect growth rate of yearling heifers nor did it influence their subsequent conception rate.

• Journal of Nutrition and Health
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• 제26권1호
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• pp.21-33
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• 1993

This balance study was performed to investigate nutritional effects of guar gum and calcium supplement for 8 weeks. 36 male rate of Sprague-Dawley strain weighing 50g were blocked into six groups : 5CN, 5GN, 5CS, 5GS, FFN, 10GN. Food intake, body weight gains, FER, PER, bioavailabity of energy, protein, fat, Ca and P, and Ca & P content of femur and kidney was measured. The results obtained in this study were summarized as follows: (1) Feed intake, weight gains, FER, PER and bioavailabilities of protein and P and the contents of Ca & P in femur of 5GB were significantly higher than 5CN and 5CS (p<0.05) but was not significant different with those 5GN. Fat bioavailabilities of 5GS was significantly lower than 5CN and 5GN (p<0.05) but was not significant different with those of 5CS. Ca contents of kidney of 5GS was significantly higher than 5CN and 5GN(p<0.05) but was not significant different with those of 5SC. (2) According to guar gum levels feed intake. FER and PER were not sifgnificantly different among groups but body weight gains, bioavailabilities of energy, protein, fat and Ca, Ca & P content of femur was significantly decreased (p<0.05). Bioavailabilities of P was significantly increased according to the guar gum levels (p<0.05). Ca contents in Kidney of 10GN was significantly higher those of 5GN(p<0.05) but P contents in kidney was not significant difference by guar gum levels. Therefore 5% supplemental guar gum in diet of obese man and diebetics could be recommended. But it should be careful in using 10% guar gum in diet.