• 한국전산구조공학회논문집
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• 제28권2호
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• pp.139-144
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• 2015

현재 방음을 위해 사용되는 흡음구조는 흡음률이 높은 재료를 이용하여 만들어진 판을 방음이 필요한 벽에 붙이거나 삽입하는 형상이다. 이러한 형상은 흡음재의 재료가 고정되기 때문에, 사용하는 환경에 따라 효율성이 변화한다는 한계점이 있다. 하지만, 흡음재 없이 흡음효과가 나타나도록 외벽의 구조를 설계한다면, 흡음재의 재료에 대한 제한이 없어져 가용 범위가 상당히 넓어지게 된다. 따라서 우리는 이러한 효율적인 외벽의 구조로서 타공판의 구조를 제안한다. 타공판이 어떻게 흡음률을 가지는 지에 대해 등가물성치를 이용한 수치해석을 통하여 검증하였다. 또한 타공판의 형상과 공명기의 형상이 유사함을 밝혀내었고, 이를 토대로 타공판이 갖는 흡음구조에 대해 분석하였다. 결과적으로 타공판은 별도의 흡음재가 없더라도 효율적인 흡음효과를 낸다는 것을 확인할 수 있었다. 또한 사용자가 타공판의 형상을 쉽게 변화시킴으로서, 특정한 주파수의 소음을 차단할 수 있어 상당히 효율적인 흡음구조임을 확인하였다. 본 연규의 결과들은 향후 자동차, 고속철도, 주택 외벽 등에 사용되는 흡음구조로서 사용될 수 있을 것이며, 나아가 흡음구조를 설계하는데 기본적인 도구가 될 수 있을 것이다.

• 경영과정보연구
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• 제17권
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• pp.107-133
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• 2005

The purpose of this study was to analyze a trend of profitability classified by characteristics of hospitals and to analyze related factors. The data for this study were derived from survey material conducted by the Korean Hospital Association on 33 hospitals in Korea between 1993 and 2002. Profitability was measured in the aspect of investment profit rate and operation profit rate with net profit to total assets, normal profit to total assets and operating margin to gross revenue as dependent variables. Independent variables were classified by general factors (ownership, number of beds, period of establishment, region), financial factors (total asset turnover, liabilities to total assets, current ratio, fixed ratio, inventories turnover, personnel costs per operation profit, material costs per operation profits), composition of manpower and facilities(personnel and area per beds), productivity index(the number of daily patients per medical doctor, the number of daily patients per nurse), the score of quality assurance activities. First, Concerning the specialists per beds or area per beds and profitability of hospitals there was not statistically significant. Second, Those hospitals having the most daily patients per nurse had significantly higher profitability than the others, but the number of daily patients per medical doctor had little effect on the profitability. Thirds, Those hospitals having a higher proportion total asset turnover tended to show significantly higher profitability compared to other hospitals, but the liabilities to total assets and liquidity ratio had a little difference to the profitability. Those hospitals having a higher proportion personnel costs per operation profit and material costs per operation profits tended to show significantly lower hospital profitability compared to other hospitals. Fourth, In regression analysis, hospital profitability had negative relationship with personnel costs per operation profit or material costs per operation profits. While it had positive relationship with total asset turnover, the number of daily patients per nurse. In conclusion, private hospitals had higher profitability than that of public hospitals. Though factors related to profitability of hospital were different according to ownership, it is important for securing appropriate profitability by operating appropriate number of nurse, raising total asset turnover, and reducing personnel costs, material costs per operation profits. This study can be used as a baseline data for planning of hospital management. But the study may be limited in that the results cannot be generalized due to its small sample size. However, this longitudinal observation of 33 hospitals over ten year period has significant merit alone.

• 디지털융복합연구
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• 제18권6호
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• pp.451-457
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• 2020

본 연구는 멀미 측정 도구인 SSQ도구를 바탕으로 가상현실에서 조작행위에 따라 나타나는 멀미 정도를 측정하여 비교분석을 통해 사이버멀미에 영향을 미치는 요인 및 증상을 규명하는 데 목적이 있다. 연구결과 첫 번째 실험인 조작방식실험에서는 간단한 조작방식이 멀미가 높게 측정되었으며 Nausea요인의 영향을 크게 받는 것으로 측정되었다. 이에 대한 증상으로 Nausea, Burping, Headache증상이 발현되었다. 두번째 신체회전방식 실험에서는 신체회전반경이 클수록 멀미가 높게 측정되었으며 Nausea요인의 영향을 크게 받는 것으로 측정되었다. 이에 대한 증상으로 Burping, Headache, Fullness of head증상이 발현되었다. 세번째 신체이동방식 실험에서는 행위를 수반하지 않은 컨트롤러의 이동방식이 멀미가 높게 측정되었으며 Nausea요인의 영향을 크게 받는 것으로 측정되었다. 이에 대한 증상으로 Sweating, Headache, Fullness of head증상이 발현되었다. 본 연구를 통해 가상현실에서 신체(고개, 상체, 하체)가 고정되고 조작이 단순 할수록 사용자는 멀미에 민감하게 반응하며, 신체회전에 있어 회전반경이 클수록 멀미에 민감하게 반응하는 것을 확인하였다. 본 연구는 VR조작행위에 대한 멀미와 영향을 미치는 요인과 증상을 규명하는데 의의가 있으며 향후 VR콘텐츠 개발자들이 사용자의 특정 행위 멀미 정도와 증상에 관하여 인지하고 콘텐츠 개발에 활용 될 것으로 기대한다.

• 한국컴퓨터정보학회논문지
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• 제19권10호
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• pp.221-230
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• 2014

이 연구에서는 학생들이 황새 복원과 관련된 주제의 프로젝트를 수행하는 과정에서 여러 학문의 지식을 활용하여 학습능력이 신장될 수 있는 방법을 제안하고자 한다. 개발 프로그램은 3 4학년군, 5 6학년군 각 4차시 총 8차시이며, 각 차시에서 황새와 관련된 초등학교 교과의 지식이나 개념을 기반으로 창의성, 문제해결능력, 의사소통능력 등의 학습능력이 신장될 수 있도록 설계하였다. 프로그램의 타당성 검증을 위해 총 12명으로 구성된 전문가 집단에 내용타당도 검증방법을 사용하였다. 타당성 평가 결과 분석을 위해서 Lawshe(1975)의 내용타당도 비율(Content Validity Ratio: CVR) 계산 공식을 활용하였다. 검증 결과는 전체 8차시의 타당성 조사 결과 3,4학년 4차시 프로그램을 제외하고는 개발 취지에 부합하는 것으로 분석되었다. 3 4학년 4차시 프로그램은 다학문적 연계 영역에 대한 문제점이 제기되었고, 이를 수정하였다. 향후 이 연구에서 제안한 프로그램을 초등학교 학생에게 적용하여 학습능력 향상 효과성 정도를 측정할 필요가 있겠다.

• 한국학교보건학회지
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• 제6권2호
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• pp.24-55
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• 1993

School health aims to guide and manage growing students from elementary schools to high schools in order to grow healthily through the formation of healthy life habits, the self-control health management guide and the making of pleasant school health environments. Even though this school health plays an important role in guiding the students who are in the period of growing to have a perfect personality as a democratic people of our country in the school education, there are many lacks, such as they still don't know the word itself, "school health" or recognize its importance. Also it's a real condition to practice items concerned with the health under the condition of unestablished structure. 1. The results of analyzing school health real conditions. Based on treatises concerned with school health and various statistical materials which are announced by concerned people. We divided and analyzed school health into the items concerned with health education, the items with health management, and the items with school health environments, and investigated the level of the present school health and its necessity. As the items concerned with health education, we investigated the necessary range of school health education, the effect of health education on children's daily life, family's health and the interesting contents of school health. And as the items with health management, I investigated children's obesity, dental caries, eyesight, clinics, a health examination, drug abuse, spirit health, providing meals for school children, and school health manpower. And as the items conerned with school health environments, we investigated the recognition of the problem of natural environments, the management of purification district around the school, the problem of environments within the school and classroom lighting. As the results of analyzing these, I realized that the present level of school health is still in unsatisfactory situation and school health is needed necessary. 2. The establishment of school health. In order to set the school health, above all, the management system of School health should be set. I classified and systemized the contents of each item which had been promoted till now according to the function. They are classified as followings Based on classifying school health into (1) health education, (2) health management and (3) health environments, I divided school health education into the health education of health subjects, the health education of concerned subjects and the education of health life. And I divided health management into the health managements for a prevention and a cure. And I divided health environments into the environment around the school and within the school. Each system set like these is not fixed invariably and I should keep the relationship of mutual supplement between health education and health management, between health management and health environments, and between health environments management and health education. When we run these systemetic school health, students' health could be maintained and improved to more proper directions.

• Journal of Korean Neurosurgical Society
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• 제61권2호
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• pp.267-276
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• 2018

Objective : The beneficial effect of hypothermia after hemicraniectomy in malignant middle cerebral artery (MCA) infarction has been controversial. We aim to investigate the safety and clinical efficacy of hypothermia after hemicraniectomy in malignant MCA infarction. Methods : From October 2012 to February 2016, 20 patients underwent hypothermia (Blanketrol III, Cincinnati Sub-Zero, Cincinnati, OH, USA) at $34^{\circ}C$ after hemicraniectomy in malignant MCA infarction (hypothermia group). The indication of hypothermia included acute cerebral infarction >2/3 of MCA territory and a Glasgow coma scale (GCS) score <11 with a midline shift >10 mm or transtentorial herniation sign (a fixed and dilated pupil). We retrospectively collected 27 patients, as the control group, who had undergone hemicraniectomy alone and simultaneously met the inclusion criteria of hypothermia between January 2010 and September 2012, before hypothermia was implemented as a treatment strategy in Dong-A University Hospital. We compared the mortality rate between the two groups and investigated hypothermia-related complications, such as postoperative bleeding, pneumonia, sepsis and arrhythmia. Results : The age, preoperative infarct volume, GCS score, National institutes of Health Stroke Scale score, and degree of midline shift were not significantly different between the two groups. Of the 20 patients in the hypothermia group, 11 patients were induced with hypothermia immediately after hemicraniectomy and hypothermia was initiated in 9 patients after the decision of hypothermia during postoperative care. The duration of hypothermia was $4{\pm}2days$ (range, 1 to 7 days). The side effects of hypothermia included two patients with arrhythmia, one with sepsis, one with pneumonia, and one with hypotension. Three cases of hypothermia were discontinued due to these side effects (one sepsis, one hypotension, and one bradycardia). The mortality rate of the hypothermia group was 15.0% and that of the control group was 40.7% (p=0.056). On the basis of the logistic regression analysis, hypothermia was considered to contribute to the decrease in mortality rate (odds ratio, 6.21; 95% confidence interval, 1.04 to 37.05; p=0.045). Conclusion : This study suggests that hypothermia after hemicraniectomy is a viable option when the progression of patients with malignant MCA infarction indicate poor prognosis.

• Asian-Australasian Journal of Animal Sciences
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• 제28권3호
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• pp.303-310
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• 2015

The study was conducted to analyze the genetic parameters of somatic cell score (SCS) of Holstein cows, which is an important indicator to udder health. Test-day records of somatic cell counts (SCC) of 305-day lactation design from first to fifth lactations were collected on Holsteins in Korea during 2000 to 2012. Records of animals within 18 to 42 months, 30 to 54 months, 42 to 66 months, 54 to 78 months, and 66 to 90 months of age at the first, second, third, fourth and fifth parities were analyzed, respectively. Somatic cell scores were calculated, and adjusted for lactation production stages by Wilmink's function. Lactation averages of SCS ($LSCS_1$ through $LSCS_5$) were derived by further adjustments of each test-day SCS for five age groups in particular lactations. Two datasets were prepared through restrictions on number of sires/herd and dams/herd, progenies/sire, and number of parities/cow to reduce data size and attain better relationships among animals. All LSCS traits were treated as individual trait and, analyzed through multiple-trait sire models and single trait animal models via VCE 6.0 software package. Herd-year was fitted as a random effect. Age at calving was regressed as a fixed covariate. The mean LSCS of five lactations were between 3.507 and 4.322 that corresponded to a SCC range between 71,000 and 125,000 cells/mL; with coefficient of variation from 28.2% to 29.9%. Heritability estimates from sire models were within the range of 0.10 to 0.16 for all LSCS. Heritability was the highest at lactation 2 from both datasets (0.14/0.16) and lowest at lactation 5 (0.11/0.10) using sire model. Heritabilities from single trait animal model analyses were slightly higher than sire models. Genetic correlations between LSCS traits were strong (0.62 to 0.99). Very strong associations (0.96 to 0.99) were present between successive records of later lactations. Phenotypic correlations were relatively weaker (<0.55). All correlations became weaker at distant lactations. The estimated breeding values (EBVs) of LSCS traits were somewhat similar over the years for a particular lactation, but increased with lactation number increment. The lowest EBV in first lactation indicated that selection for SCS (mastitis resistance) might be better with later lactation records. It is expected that results obtained from these multi-trait lactation model analyses, being the first large scale SCS data analysis in Korea, would create a good starting step for application of advanced statistical tools for future genomic studies focusing on selection for mastitis resistance in Holsteins of Korea.

• 한국산업보건학회지
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• 제6권1호
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• pp.125-137
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• 1996

This study was designed to investigate effects of relative humidity on the breakthrough of charcoal tubes at a fixed vapor concentration and sampling time during mixed organic vapor sampling. A vapor generator was used to generate three different concentrations of mixed organic vapor and a stainless steel chamber was fabricated and utilized to maintain three different percentages of relative humidity while maintaining a constant temperature. The results were as follows; 1. At high relative humidity, breakthrough of mixed organic vapor occurred quickly at low vapor concentration than at high vapor concentration because of the reduced adsorption volume of charcoal tube due to humidity. 2. Breakthrough by competitive adsorption of vapors onto charcoal tube was observed at first from n-hexane having the lowest boiling point and highest vapor pressure among the three organic vapors investigated, followed by TCE. No breakthrough was observed from toluene under all experimental conditions. 3. For n-hexane, breakthrough was observed after 2 hours of sampling and breakthrough rates were increased as relative humidity increased. For TCE, breakthrough was found after 3 hours of sampling and breakthrough rates by sampling time were increased as vapor concentration increased. 4. The adsorbed amount of mixed organic vapor at breakthrough was shown to have statistically significant correlations with sampling time, relative humidity, and vapor concentration in descending order of correlation. Relative humidity and sampling time for n-hexane and sampling time and concentration for TCE were both statistically significantly correlated. 5. Relative humidity was found to affect the amount of breakthrough of mixed organic vapor and n-hexane. Among three percentages of relative humidity investigated, the amount of breakthrough at 85 % relative humidity was significantly larger than those of at lower percentages of relative humidity. No statistically significant difference was found between 25 % and 55 % relative humidity. 6. The results of multiple regression analysis between breakthrough and relative humidity, vapor concentrations showed that the coefficient of determination of mixed organic vapor was 0.263 and those of n-hexane and TCE were 0.275 and 0.189, respectively. 7. Flow rates of sampling pumps used were found to be affected by relative humidity present. At 25 %, 55 %, and 85 % relative humidity, the relative errors of sampling pump were 1.4 %, 13.4 %, and 18.6 %, respectively. In conclusion, the results of this study showed that high relative humidity could reduce the adsorption volume of charcoal tubes and subsequently increase breakthrough rates. Therefore, to prevent breakthrough when sampling mixed organic vapors, it is suggested that either sampling volume be reduced on the flow rate be lowered so as to minimize breakthrough of the most volatile organic vapor in the mixture. In addition, since the flow rates of a sampling pump can be adversely affected by high relative humidity, it is recommended to use a constant flow mode pump when sampling in the highly humid environment.

• 디자인학연구
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• 제20권1호
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• pp.243-252
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• 2007

오늘날 기술적인 차이는 적어지고 기업들이 출시하는 제품이 유사해져감에 따라 경쟁적 우위를 위한 대안으로 기업은 브랜드를 제시한다. 제품의 질적인 우위는 쉽게 다른 경쟁 기업들에게 모방되어질 수 있지만 무형적인 가치를 포괄하는 브랜드는 쉽게 모방되기가 어렵기 때문에 기업의 차별화를 만들어 주고 고객과의 관계를 결정한다는 점에서 글로벌 경쟁 시대에서 더욱 중요해 지고 있다. 또한 디자인이미지는 기업 경쟁력에 있어서 중요한 부분을 차지하는 요소이다. 기업이 내세우는 디자인이미지는 브랜드를 반영하며, 브랜드는 기업이미지와 기업이 갖는 철학을 대변한다. 이에 다양한 제품들이 갖는 디자인이미지는 브랜드가치 향상을 위해 중요한 역할을 한다. 기업은 이러한 디자인이미지의 정체성을 구축함으로써 브랜드를 향상시킬 수 있다. 따라서 디자인이미지의 정체성이 없거나 디자인이미지들이 정체성을 갖지 못하고 일탈된 부분에 대한 연구는 중요하다. 본 연구는 기존의 기업경쟁력을 위해서 브랜드를 강화시켜야하며 이를 위해서는 디자인이미지가 브랜드의 정체성에 가깝게 이루어져야 한다는 부분에 초점을 두었다. 선행연구와 이론적 배경을 바탕으로 소비자가 구매하는 제품이 가지고 있는 디자인 이미지를 중심으로 디자인아이덴티티 영역을 찾는 것이다. 먼저 소비자들이 생각하는 디자인이미지의 동질성을 규명하고, 이를 바탕으로 이미지들이 나타내는 방향성을 분석하여, 기업의 브랜드 전략에 개선이 될 수 있는 디자인아이덴티티 영역과 브랜드와의 관계를 모색할 것이다.

• 한국시뮬레이션학회논문지
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• 제27권2호
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• pp.35-48
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• 2018

북한의 전술탄도미사일(TBM, tactical ballistic missile)에 대한 방공 분야 연구는 빠른 속도로 변화하는 전장 환경을 고려해야 한다. 아군 유도탄의 표적 재지정 연구는 동적인 전장에 대한 대응뿐만 아니라 아군 방어 자산의 효과적인 운용을 가능하게 한다. 현재까지 진행된 연구는 의사 결정 과정에서 중요한 역할을 하는 TBM의 명중 확률이 고정된 값이기 때문에 실시간 전장 상황을 대변하지 못한다. 따라서 본 연구는 실시간 전장 환경을 고려한 명중 확률을 기반으로 의사 결정을 내리는 표적 재지정 알고리즘을 제안한다. 제안 방법론은 랜덤 포레스트와 무빙윈도우(moving window) 기법을 사용하여 현재 TBM의 위치 및 속도 정보로 TBM의 예상 궤적을 예측하는 궤적 예측 모형을 포함한다. 예상 명중 확률은 궤적 예측 모형과 유도탄의 시뮬레이터를 통해서 계산할 수 있으며, 계산된 명중 확률은 유도탄에 대한 표적 재지정 알고리즘의 의사결정 기준이 된다. 실험에서는 TBM 궤적 예측 모형에 사용한 방법론의 타당성이 검증되었으며, 표적 재지정 의사 결정 과정에서 제안된 모델을 통해 명중 확률을 사용하는 것의 우수성이 확인되었다.