• 대한전자공학회논문지TC
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• 제48권5호
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• pp.33-39
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• 2011

두명의 사용자를 위한 무선 통신에서 심볼 간 간섭 및 다중 접속 간섭을 최소화하는 유동적인 전송률 back-off 적용 지연 time reversal (TR) 기법의 성능을 평가하였다. 지연 TR 기법의 성능을 기존 full-rate TR과 full back-off TR의 성능과 비교하였으며, guard interval이 1보다 큰 경우 비트오차율 측면에서 지연 TR 기법의 성능이 full-rate TR이나 full back-off TR보다 우수함을 확인하였다.

• Journal of Biosystems Engineering
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• 제35권2호
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• pp.132-137
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• 2010

Site-specific N application for corn is one of the precision crop management. To implement the site-specific N application, various nitrogen stress sensing methods, including aerial image, tissue analysis, soil sampling analysis, and SPAD meter readings, have been used. Use of side-dressing, an efficient nitrogen application method than a uniform application in either late fall or early spring, relies mainly on the capability of nitrogen deficiency detection. This paper presents map-based variable rate nitrogen application based using a multi-spectral corn nitrogen deficiency(CND) sensor. This sensor assess the nitrogen stress by means of the estimated SPAD reading calculated from the corn leave reflectance. The estimated SPAD value from the CND sensor system and location information form DGPS of each field block was combined into the field map using a ArcView program. Then this map was converted into a raster file for a map-based variable rate application software. The relative SPAD (RSPAD = SPAD over reference SPAD) was investigated 2 weeks after the treatments. The results showed that the map-based variable rate application system was feasible.

• 응용통계연구
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• 제30권6호
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• pp.993-1004
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• 2017

표본조사에서는 추정의 정확성 및 정밀성 향상을 위해 흔히 층화추출법을 사용하며 층 내에서는 동일한 표본 가중치를 이용하여 표본을 추출한다. 그러나 실제 응답률은 관심변수 값에 영향을 받을 수 있기 때문에 주어진 동일한 가중치는 응답률을 반영하여 보정되어야 한다. 또한 관심변수가 연속형 보조변수와 선형 관계가 있고 보조변수를 기준으로 층이 나누어진 경우에는 층 내에서 동일한 가중치를 사용하는 것 보다 층을 세분화한 후 얻어진 가중치를 사용하는 것이 효과적일 수 있다. 본 연구에서는 응답률이 관심변수 자료 값의 지수함수이고, 관심변수가 보조변수와 선형 관계가 있을 때 정보적 표본설계 기법을 이용하여 추정의 정확성과 정밀성을 높이는 방법을 제안하였다. 또한 모의실험을 통하여 제안된 방법의 우수성을 확인하였다.

• 대한간호학회지
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• 제11권2호
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• pp.105-123
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• 1981

This study was carried out during the month of September 1976 to analyse and compare the health complaints of two groups of the university women, those who lived at home and those who lived in the university dormitory. The purpose of the study was to provide basic data required by the university health program for planning related to the health need of women students. The study sample consisted of 434 students living in the dormitory and 381 students living at home enrolled for the fall semester 1976 in a womens university in Seoul. The instrument used for the collection of data was an abridged version of a modified Cornell Medical Index. The questionarre included 35 items related to physical health complaint and 22 items related to mental health complaints. The data was treated by a computer (SPSS) using one way analysis, the Fishers' ratio and Chi-Square test at the 5％ level were used for the test for statistical significance. The interpretation of this study is limited due to the sample which was restricted to one university and not randomly selected. To guide the direction of the study, it was hypothesized that the rate of expressed health problems of students living in the dormitory would be Venter than that of students living at home. The hypothesis was tested and rejected. The following is a summary of the findings; 1. Total health (physical and mental) complaints a. There was no statistically significant difference between the home and dormitory groups with regard to total health complaints expressed. b. The rate of total complaints expressed by the home group significantly higher than dormitory group only among third year students. c. There was no statistically significant between the home and dormitory groups in their satisfaction with their economic situation. d. The home group showed a significantly higher rate of complaints related to the Nervous System compared to that of the dormitory group. 2. Physical health complaints a. Students living at home showed a significantly higher rate of physical complaints than the dormitory group. b. When the year variable was controlled, the third year was the only group which showed a different rate between home and dormitory groups; the home group presented a higher rate. c. Since the year variable seemed to affect the physical complaints those data were further analysed to see whether the specific system areas were operating as variables in each year. The results were as follow: Among the home group, First year students showed a higher rate in Family History of Disease, while the third year students more Nervous System and Cardiovascular System complaints. Among the dormitory group, only fourth year students showed a higher rate in the Skeletal-Muscular System. This was the only area the dormitory group though only for the fourth year students supported the hypothesis. d. When the economic satisfaction variable was controlled, the satisfied group was the only group which showed a different rate between home and dormitory groups; the home group presented higher rate. e. Since the economic satisfaction variable seemed to affect the physical complaints those data were further analyzed to see whether the specific system areas were operating as variables in each economic satisfaction level, but there was no statistically significant difference between home and dormitory groups. 3. Mental health complaints a. There was no significantly difference between home and dormitory groups with regard to mental health complaints expressed. b. When the year variable was controlled the third year group was the only group which showed a different rate between home and dormitory groups; the home group presented a higher rate. c. Since the year variable seemed to affect the mental complaints, those data were further analyzed to see whether the specific system areas were operatings variables in each economic satisfaction level. The result were as follows: Among the home group, the third year students showed higher rates in Inadequacy and Anxiety. d. When the economic satisfaction variable was controlled, the very satisfied group was the only group which showed a different rate between home and dormitory groups: the home group presented a higher rate. Since the economic satisfaction variable seemed to affect the mental complaints, those data were further analysed to see whether the specific system areas were operating as variables in each economic satisfaction level, but there was no statistical significant difference between the home and dormitory groups. Although the social environment of dormitory life differs from family life, there was no difference in the rate of total health problem complaints between the home and dormitory groups but the home group showed a higher rate of physical health complaints than the dormitory group. Possible positive factors influencing dormitory life and negative factors influencing family life affecting health complaints must be explored in order to relate to the health needs of the university health program. This study could not define the causes for the fewer physical complaints of dormitory students living at home. Further study of such causal factors recommended in order to provide the data needed to contribute to a more effective health program.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.484-489
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• 2003

The mass flow rate of gas flow through critical nozzle depends on the nozzle supply conditions and the cross-sectional area at the nozzle throat. In order that the critical nozzle can be operated at a wide range of supply conditions, the nozzle throat diameter should be controlled to change the flow passage area. This can be achieved by means of a variable critical nozzle. In the present study, both experimental and computational works are performed to develop variable critical nozzle. A cone-cylinder with a diameter of d is inserted into conventional critical nozzle. It can move both upstream and downstream, thereby changing the cross-sectional area of the nozzle throat. Computational work using the axisymmetric, compressible Navier-Stokes equations is carried out to simulate the variable critical nozzle flow. An experiment is performed to measure the mass flow rate through variable critical nozzle. The present computational results are in close agreement with measured ones. The boundary layer displacement and momentum thickness are given as a function of Reynolds number. An empirical equation is obtained to predict the discharge coefficient of variable critical nozzle.

• Journal of the Korean Data and Information Science Society
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• 제23권6호
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• pp.1289-1297
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• 2012

We consider a general compound Poisson risk model in which the premium rate is surplus dependent. We analyze the joint distribution of the surplus immediately before ruin, the deffcit at ruin and the time of ruin by solving the integro-differential equation for the Gerber-Shiu discounted penalty function.

• Journal of Biosystems Engineering
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• 제31권6호
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• pp.482-488
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• 2006

Application of precision farming technology to rice cultivation could be an effective measure for rice quality improvement and environment-friendly agriculture. This study was conducted to develope a variable rate pneumatic granule applicator. Previous study reported that application uniformity of the prototype machine (C.V. = 23.3%) was not satisfactory. To improve the uniformity, increase of blow-head number from 12 to 16 was suggested. Analysis of the pneumatic conveying system showed that increase of number of blow-head was possible. Three-way variance analysis of the modified applicator showed that inserting length should be changed according to granule metering rate. The range of metering rate from 27.3 to 417.9 g/s were divided into 4 levels and 4 sets of inserting lengths were determined to ensure CV values less than 15%. The revised applicator showed satisfactory C.V. values of 9.4 to 14.6% in the metering rate. Granule conveying pattern was observed using a high speed camera and judged as the homogeneous flow pattern.

• 사상체질의학회지
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• 제19권1호
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• pp.60-77
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• 2007

1. Objectives This is the comparative study with hand-operated measurement method and Automatic measurement method, in order to convert the automatic measurement method. 2. Methods We measured the body of patients(hand-operated Width 5 Places and hand-operated circumference 8 place,Automatic Width 5 and automatic circumference 8 place by 3D body measuring instrument) and analyzed the anthropometric data divding into sex&age. 362 patient's data are used in the analysis. 3. Results and Conclusions 1) 1th circumference variable which standing was not a sasang constitutional difference. 2) Diagnostic accuracy rate of the body measurement was 50-80%. 3) Diagnostic accuracy rate of man is higher than Diagnostic accuracy rate of women 4) Diagnostic accuracy rate of Automatic & hand-operated measuring was not a big difference.

• 한국전문물리치료학회지
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• 제12권3호
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• pp.74-83
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• 2005

The purpose of this study was to produce the regression equation from non-exercise $VO_{2max}$ of healthy young adults and to develop a maximal oxygen consumption ($VO_{2max}$) regression model. This model was based on heart rate non-exercise predictor variables (rest heart rate, maximal heart rate/rest heart rate), as an extra addition to the general regression which can reflect an individual's inherent or acquired cardiorespiratory fitness. The subjects were 101 healthy young adults aged 19 to 35 years. Exercise testing was measured by using a Balke protocol for treadmill and indirect calorimetry. The prediction equation was analyzed by using stepwise multiple regression procedures. The mean of $VO_{2max}$ was $39.02{\pm}6.72\;m{\ell}/kg/min$ (mean${\pm}$SD). The greatest variable correlated to $VO_{2max}$ was %fat. The predictor variable used in the non-exercise $VO_{2max}$ included %fat, gender, habitual physical activity and $HR_{max}/HR_{rest}$. The non-exercise $VO_{2max}$ estimation was as follows: $VO_{2max}$($m{\ell}/kg/min$)=55.58-.41(%fat)+.59(physical activity rating)-2.69($HR_{max}/HR_{rest}$)-5.36 (male=0, female=1); (R=.85, SEE=3.64, R2=.72: including heart rate variable); $VO_{2max}$($m{\ell}/kg/min$)=48.47-.41(%fat)+.45(physical activity rating)-5.12 (male=0, female=1); (R=.84, SEE=3.74, R2=.70: with the exception of heart rate variable). As an added heart rate variable, there was only a 2% coefficient of determination improved. Therefore, these results demonstrated that heart rate variable correlation with a non-exercise regression model was very low. In conclusion, for healthy young korean adults, those variables that can affect non-exercise $VO_{2max}$ estimation turned out to be only % fat, gender, and physical activity. We suggest that further research of predictor variables for non-exercise $VO_{2max}$ is necessary for different patient groups who cannot perform maximal exercise or submaximal exercise.

• 경영과정보연구
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• 제34권4호
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• pp.67-81
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• 2015

본 연구의 목적은 보건의료산업 주식 시장에 대해 거시경제변수에 대한 요인이 미치는 영향을 알아보고자 한다. 첫째, 의약품지수는 국공채금리와 환율을 원인변수로 하며 콜금리변수와는 상호영향 관계를 가진다. 즉 금리와 환율의 변화는 의약품산업에 영향을 미치는 변수로서 주의해야 한다는 것이다. 둘째, 의료기기지수는 콜금리, 국공채금리, 환율에 대해 상호 원인변수로 작용하며 경상수지변수를 원인변수로 한다. 즉 의료기기산업에 대해 금리와 환율 그리고 경상수지의 변화가 영향을 미칠 수 있다는 것이다. 셋째, 의약품 지수에 영향을 미치는 변수의 관계를 추가적으로 분석하면 콜금리와 환율은 음(-)의 관계이며 국공채금리와는 양(+)의 관계를 가진다. 의료기기 지수에 영향을 미치는 변수의 관계를 분석하면 환율과는 음(-)의 관계이며 국공채금리와는 양(+)의 관계를 가진다.