• 한국철도학회논문집
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• 제7권1호
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• pp.60-64
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• 2004

Harmonic current originating from electric locomotives can be magnified due to the impedance characteristics of power supply circuit and bring about various problems. That is, electromagnetic interference with communication lines, operational trouble in signaling, overheat and/or vibration in power capacitor, mis-operation in protection relay and so on. Therefore, the exact assessment of the harmonic current flow must be undertaken at design and planning stage for the electric traction systems. for these reasons, this study propose a new approach to model and to analyse traction power feeding system focused on system response to current and voltage harmonic(PART I). Measurements of harmonics are also performed for railway power supply systems under normal operation. Spectrum and distortion analyses in measurement data are variously described in PART II.

• 대한조선학회논문집
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• 제45권6호
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• pp.735-749
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• 2008

For the development of the original technique of structural safety assessment of Cargo Containment System(CCS) in membrane type LNG carriers, it is necessary to understand the characteristics of dynamic response behavior of CCS structure under sloshing impact pressure. In the previous study, the wet drop impact response analyses of CCS structure in membrane Mark III type LNG carriers were carried out by using Fluid-Structure Interaction(FSI) analysis technique of LS-DYNA code, and were also validated through a series of wet drop experiments for the enhancement of more accurate shock response analysis technique. In this study, the characteristics of structural shock response behaviors of CCS structure were sufficiently figured out by careful examinations of the effects of specimen weight, drop height, incident angle, corrugation and stiffness of inner hull on its shock response behaviors. The shock response analysis of upward shooting fluid to inner hull was performed, and the reason of faster strain response than shock pressure one was also figured out.

• 한국환경복원기술학회지
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• 제27권1호
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• pp.45-54
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• 2024

This study developed a model to evaluate the co-benefits and trade-off effects between biodiversity and carbon storage capacity based on the implementation locations of nature-based solutions. The model aims to propose optimal implementation locations by using the conceptual idea of edge effects for carbon storage and connectivity for biodiversity. The co-benefits were considered by simultaneously taking into account two effects rather than a single effect. Trade-off effects were observed among optimal plans through a comparison of benefits. The NSGA-II multi-objective optimization algorithm was utilized, confirming the identification of Pareto-optimal solutions. The implementation patterns of Pareto-optimal solutions for green areas were examined. This study holds significance in proposing optimal locations by evaluating various co-benefits and trade-off effects of nature-based solutions. By advancing models based on this evaluation framework, it is anticipated that the assessment of co-benefits and trade-off effects among various benefits of nature-based solutions, such as climate change mitigation, enhancement of biodiversity, and provision of ecosystem services, can be accomplished.

• Acute and Critical Care
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• 제33권4호
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• pp.216-221
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• 2018

Background: In this study, we analyze the performance of the Acute Physiology and Chronic Health Evaluation (APACHE) II, APACHE IV, Simplified Acute Physiology Score (SAPS) 3, and Mortality Probability Model $(MPM)_0$ III in order to determine which system best implements data related to the severity of medical intensive care unit (ICU) patients. Methods: The present study was a retrospective investigation analyzing the discrimination and calibration of APACHE II, APACHE IV, SAPS 3, and $MPM_0$ III when used to evaluate medical ICU patients. Data were collected for 788 patients admitted to the ICU from January 1, 2015 to December 31, 2015. All patients were aged 18 years or older with ICU stays of at least 24 hours. The discrimination abilities of the three systems were evaluated using c-statistics, while calibration was evaluated by the Hosmer-Lemeshow test. A severity correction model was created using logistics regression analysis. Results: For the APACHE IV, SAPS 3, $MPM_0$ III, and APACHE II systems, the area under the receiver operating characteristic curves was 0.745 for APACHE IV, resulting in the highest discrimination among all four scoring systems. The value was 0.729 for APACHE II, 0.700 for SAP 3, and 0.670 for $MPM_0$ III. All severity scoring systems showed good calibrations: APACHE II (chi-square, 12.540; P=0.129), APACHE IV (chi-square, 6.959; P=0.541), SAPS 3 (chi-square, 9.290; P=0.318), and $MPM_0$ III (chi-square, 11.128; P=0.133). Conclusions: APACHE IV provided the best discrimination and calibration abilities and was useful for quality assessment and predicting mortality in medical ICU patients.

• 한국물환경학회지
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• 제27권1호
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• pp.61-72
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• 2011

유역 단위 수문 및 수질 평가 모형인 SWAT 모형을 이용한 유역 내 정확한 수문과 비점오염원 거동을 평가하기 위해서는 유역 적용에 앞서 모형의 정확성 평가가 우선시 되어야 한다. SWAT 모형의 수문 보정및 검정 시, Nash-Sutcliffe의 효율계수(EI)가 널리 사용되고 있다. 그러나 이러한 EI 값은 비교되어지는 값들의 범위 중 큰 값 즉, 수문 분석에 있어 고유량에 대해 민감하게 영향을 받는 것으로 알려져 있다. 그리하여 본 연구에서는 보다 정확한 수문 분석을 위해 K-means 군집화 알고리즘을 이용한 웹기반의 EI 평가시스템을 개발하였고, 이를 SWAT 모형의 수문 평가에 적용하였다. 본 연구의 결과 전체 유량의 EI 값은 높았지만, 수문성분에 따른 EI 값은 높지 않았다. SWAT 모형의 수문 보정 및 검정에 널리 활용되고 있는 SWAT auto-calibration tool은 전체 유량에 대해서는 높은 EI 값을 산정하는 것으로 보이지만, 직접유출과 기저유출 각각에 대한 유량 그룹 I 과 II 에 대해서는 대부분 음수(-)의 EI 값을 보였다. 그리하여 본 연구 결과를 통해 SWAT 모형의 수문성분 평가에 있어 보다 정확한 평가를 위해서는 직접유출과 기저유출에 대한 각각의 유량 그룹에 대해 양수(+)의 EI 값이 산정되도록 모형 보정 및 검정의 수행 필요할 것으로 사료된다.

• 대한영양사협회학술지
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• 제5권2호
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• pp.137-144
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• 1999

In Korea, the practice of nutrition education program at the worksite has not yet been implemented, especially for the workers who are at risk for health. Accordingly, the worksite nutrition program, education, and nutrition counseling are necessary. In this study, the worksite nutrition program was developed from June, 1997 to May, 1998. For this program, we surveyed the workers' age and the levels of education, income and physical activity. We developed the proper dietary intake questionnaire to evaluate the employees' nutritional status and the nutrition index which is a simple tool to assess nutrient intakes of the employees at the worksites. To demonstrate the validity of the developed nutritional assessment tools, the CAN(Computer Aided Nutritional) program and Hyunmin system developed by the Korean Nutrition Society and the Korean Dietetic Association respectively, were used as references. The result of the validity test for the dietary assessment method that we have been developed revealed that the method was valid showing no significant difference among the various methods. However, the carbohydrate intake measured by the CAN program was higher than those of others. The validity test results for the nutrient index method showed that there was no significant difference among the methods, except the carbohydrate intake measured by the Hyunmin system was lower that those of others. As a result, we concluded that the dietary assessment methods that we had been developed, were valid method to measure the nutrient intakes of the employees at the worksites.

• 대한인간공학회지
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• 제33권1호
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• pp.39-48
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• 2014

Objective: This entire study has two parts. Study I aimed to develop a psychological assessment scale and the study II aimed to investigate the effects of LFN (low frequency noise) on the psychological responses in humans, using the scale developed in the study I. Background: LFN is known to have a negative impact on the functioning of humans. The negative impact of LFN can be categorized into two major areas of functioning of humans, physiological and psychological areas of functioning. The physiological impact can cause abnormalities in threshold, balancing and/or vestibular system, cardiovascular system and, hormone changes. Psychological functioning includes cognition, communication, mental health, and annoyance. Method: 182 college students participated in the study I in development of a psychological assessment scale and 42 paid volunteers participated in the study II to measure psychological responses. The LFN stimuli consisted of 12 different pure tones and 12 different 1 octave-band white noises and each stimulus had 4 different frequencies and 3 different sounds pressure levels. Results: We developed the psychological assessment scale consisting of 17 items with 3 dimensions of psychological responses (i.e., perceived physical, perceived physiological, and emotional responses). The main findings of LFN on the responses were as follows: 1. Perceived psychological responses showed a linear relation with SPL (sound pressure level), that is the higher the SPL is, the higher the negative psychological responses were. 2. Psychological responses showed quadric relations with SPL in general. 3. More negative responses at 31.5Hz LFN than those of 63 and 125Hz were reported, which is deemed to be caused by perceived vibration by 31.5Hz. 'Perceived vibration' at 31.5Hz than those of other frequencies of LFN is deemed to have amplified the negative psychological response. Consequently there found different effects of low frequency noise with different frequencies and intensity (SPL) on multiple psychological responses. Conclusion: Three dimensions of psychological responses drawn in regard to this study differed from others in the frequencies and SLP of LFN. Negative psychological responses are deemed to be differently affected by the frequency, SPL of the LFN and 'feel vibration' induced by the LFN. Application: The psychological scale from our study can be applied in quantitative psychological measurement of LFN at home or industrial environment. In addition, it can also help design systems to block LFN to provide optimal conditions if used the study outcome, .i.e., the relations between physical and psychological responses of LFN.

• 한국환경복원기술학회지
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• 제7권1호
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• pp.116-127
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• 2004

The objectives of this study are to build up the concept of Environment-Oriented Land Suitability Assessment(EOLSA) and to develop the EOLSA mapping system by applying the EOLSA criteria to the case study area. In order to draw out the EOLSA critera, this study adopted the Delphi method including the experts' awareness survey to urban planners as well as environmental researchers in May and June 2001. As a result, the concept of EPLSA was defined as a process of land use planning to scientifically assess the physical and environmental value of land and to classify conservation aptitude into several grades for the sustainable management of environmental resources. With an outcome of applying the EOLSA criteria with five degrees to the Seoul Metropolitan Area (SMA), Grade I, indicating the highest conservation value, accounted for 57.76% of the SMA. Then, Grade II reached up to 15.06%, Grade III 3.12%, Grade IV 15.92%, and Grade V, the lowest conservation value, 7.99% respectively. And also, the case analysis showed that the share of Grade I area was the highest in Gapyong county and Yangpyong county, Pochon county, Yeonchon county, Yongin city in the order and the lowest in Kwangmyong city, Osan city, Kunpo city, Kuri city, and Buchon city.

• 사상체질의학회지
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• 제26권2호
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• pp.194-204
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• 2014

Objectives The aim of this study was to examine significant improvement of gait ataxia, vertigo and tremor after treatment with Sipyimigwanjung-tang, Hyangsayangwi-tang in a Soeumin Greater Yin Symptomatology patient Diagnosed as Cerebellar ataxia. Methods The patient was diagnosed with Soeumin Greater Yin Symptomatology and treated with Soeumin's constitutional medications and acupuncture. The primary outcome measures for this study were the Unified Multiple System Atrophy Rating Scale(UMSARS) and Cerebellar function test to assess the overall function of patient. Secondary outcome assessment included Global Assessment Scale(GAS), change of patient's sleep, stool and digestion. Results The symptoms of gait ataxia, vertigo and tremor decreased from GAS 100 to GAS 0~40 after treatment, and the UMSARS score decreased in Part I, II. Conclusions This case showed that Sasang Constitutional medicine treatment can be effective treatment method for cerebellar ataxia. We consider that consistent treatment can contribute to improve the patient's quality of life.

• Journal of Radiation Protection and Research
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• 제24권2호
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• pp.101-108
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• 1999

극저준위 방사성액체폐기물 처리를 위하여 공기의 온도와 습도 및 유입 공기의 속도에 따른 증발량의 관계를 천을 이용한 강제증발실험 장치로 실험하였다. 그 결과 각각의 변수와 증발량의 상관관계를 실험식으로 도출하였다. 또한 Cs-137 을 함유한 모의폐액을 사용하여 본 장치에 대한 제염 계수를 얻은 결과 $DF=10^4$으로 나타났다. TRlGA Mark II & III 연구용 원자로 폐로시 발생되는 극저준위 방사성액체폐기물을 증발장치로 처리할 때 주변의 일반개인에 대한 연간 피폭선량을 보수적으로 평가한 결과, 유효선량 (effective dose)은 $1.01{\times}10^{-3}mSv$이고, 환경으로 배출되는 공기의 방사능 농도(Cs-137)는 $4.637{\times}10^{-14}\;{\mu}Ci/cc$ air 이다. 따라서 극저준위 방사성액체폐기물의 처리를 위하여 강제증발장치를 사용하는 것은 주민에 아무런 영향이 없음을 알 수 있었다.