• 플랜트 저널
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• 제11권2호
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• pp.39-44
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• 2015

본 연구는 석탄화력 탈황설비인 흡수탑 교반기용 유도전동기의 베어링 결함진단을 토대로 전류 스펙트럼 해석이 예측정비 수단으로서 활용할 수 있는지를 논하고자 하였다. 베어링의 교체 전과 후의 전류스펙트럼 해석을 하고 베어링을 육안 점검하여 비교 분석함으로써 실제 발전 산업현장에서 부하운전중인 유도전동기의 베어링의 결함진단을 하였다. 분석 결과, 볼과 외륜의 베어링 결함에 해당하는 주파수성분이 예측한 값으로 검출되었고 전압기준의 진폭크기로 환산하여 베어링 교체하기 전과 후를 비교하면 결함이 진행될 경우 볼 결함에서는 약 2.9배 증가되고 외륜 결함에서는 약 2.24배 증가 되었음을 확인할 수 있었다. 이 같은 결론으로 인위적인 고장요소에 의한 베어링 결함진단 뿐만 아니라 산업현장에서 부하 운전되고 있는 유도전동기의 베어링 결함을 사전에 예측하는데 있어서도 매우 유용하였다.

• Ocean Systems Engineering
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• 제9권4호
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• pp.409-422
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• 2019

Sloshing is a phenomenon which may lead to dynamic stability and damages on the local structure of the tank. Hence, several anti-sloshing devices are introduced in order to reduce the impact pressure and free surface elevation of liquid. A fixed baffle is the most prevailing anti-sloshing mechanism compared to the other methods. However, the additional of the baffle as the internal structure of the LNG tank can lead to frequent damages in long-term usage as this structure absorbs the sloshing loads and thus increases the maintenance cost and downtime. In this paper, a novel type of floating baffle is proposed to suppress the sloshing effect in LNG tank without the need for reconstructing the tank. The sloshing phenomenon in a membrane type LNG tank model was excited under sway motion with 30% and 50% filling condition in the model test. A regular motion by a linear actuator was applied to the tank model at different amplitudes and constant period at 1.1 seconds. Three pressure sensors were installed on the tank wall to measure the impact pressure, and a high-speed camera was utilized to record the sloshing motion. The floater baffle was modeled on the basis of uniform-discretization of domain and tested based on parametric variations. Data of pressure sensors were collected for cases without- and with-floating baffle. The results indicated successful reduction of surface run-up and impulsive pressure by using a floating baffle. The findings are expected to bring significant impacts towards safer sea transportation of LNG.

• Journal of Yeungnam Medical Science
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• 제33권2호
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• pp.112-115
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• 2016

Lymphocytic interstitial pneumonia (LIP) is a rare benign lymphoproliferative disorder characterized by diffuse infiltration of the pulmonary parenchymal interstitium by polyclonal lymphocytes and plasma cells. LIP has been associated with a variety of clinical conditions; such as connective tissue disorders and other immune system abnormalities. Treatment usually involves administration of corticosteroids and other immunosuppressants. We report on a 38-year-old female patient who complained of shortness of breath, dry mouth, and dry eyes for more than 1 month, and was positive for Raynaud's phenomenon. Based on surgical biopsy, she was diagnosed as having LIP accompanied by $Sj{\ddot{o}}gren^{\prime}s$ syndrome. The patient was treated with high-dose steroids followed by maintenance therapy for approximately 2 years, and her condition improved.

• 한국전산구조공학회논문집
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• 제18권1호
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• pp.93-99
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• 2005

최근, 제철소, 원자력 및 수${\cdot}$화력 발전소 등 주요 기간설비에 있어서 해당 구조물, 관련 장비들의 노후화에 따른 고장진단, 수리보수, 안전성 평가와 잔여 수명 예측을 통한 수명연장에 관련된 요구가 높아지고 있다. 손상발생 시나리오의 구축, 정밀해석기법의 확립, 위험성 혹은 신뢰성 평가기술 개발 등에 관한 연구가 이러한 요구를 반영하여 활발하게 수행되고 있다. 본 연구에서는 구조물의 안전성 평가분야에서 가장 활발하게 사용되는 유한요소해석기술을 이용하여 제철설비 구조물의 안전성을 평가하는 절차를 개발하고 실제 가동 중인 고로를 대상으로 적용하여 유용성을 검토하였다.

• 환경위생공학
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• 제6권1호
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• pp.7-25
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• 1991

Until now, pure drinking water grnerally menas the water without taste, odor, general bacteria, coliform, and other exotic substance. Such a definition has been changing recently due to the finding of numerous other inorganic and organic substances unknown to us. 10 years ago, major causes of death were infectious agents and parasites contained in water, but recently, it has become apparent that some substances contained in drinking water cause cancer and heart diseases. We must drink about 2L of water everyday in order to maintain healthy condition. Waters used for drinking include tap water, well water, spring water, filtered water, etc., but the quality of drinking water has more polluted due to the industrial development and population increase. For example, industrial waste waters from industrial plants pollute the water supply sources ; toxic substances contained in the waste waters pollute the ground water sources by penetrating the geological strata, and municipal, livestock, public building waste waters also pollute the water supply sources. Sometimes, the polluted surface waters were announced to be polluted by various kinds of orgainc substance, and it is reported that the pollution of ground water by orga nic substances has few in number but high in its concectration comparing with those of surface water. As the water quality pollution level increases, so the amount of disinfectant also increase. For example, chlorine solution, one of widely used disinfectants, creates trihalomethane(THM), a carcinogen, and halogen compounds. According to Oliver, through chlorine disinfection process, humine substance and chlorine create bolatile organic halide and nonvolatile organic halide by chemical reaction. There are tens or hundreds filtering devices, but filtering principles and maintenance metjhods are different, so their efficiency tests are needed. According to Smith, the effeciency tests aginst over 30 Ameican filtering devices show that 10 devices can remove 85% of volatile organics and further studies on filtered waters are underway. In consideration of important impacts of polluted drinking water on national health, authors studied the state of water quality pollution against tap water used as drinking water, filtration device passed water, ground water, and conserved drinking water ; tested the efficiency of filtration devices for tap water ; tried to sep up the detection method by using ion chromatography based on negative ion and positive ion by using single column, and attemped the simple filtration method for general households.

• 설비공학논문집
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• 제23권9호
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• pp.610-619
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• 2011

This paper investigates the simplified comfort index and control logic for VRF (Variable Refrigerant Flow) system by using 3 environmental factors such as temperature, humidity and air flow. Indoor test under thermal load was conducted to explore relationship of each environment factors that is related to simplified comfort index. Simplified comfort function that has 3 environmental variables was proposed based on survey results. Each factor is measured and comfort preference was surveyed by more than 30 subjects in the indoor comfort test. Moreover, control logic for VRF system was developed and then simulated by using thermal load calculation method and verified with test. The proposed comfort function was in good agreement with survey results, and also verification test trend of comfort change and maintenance are quite similar with survey. Furthermore, through the additional test data analysis some differences of comfort according to position of people staying in the test room were additionally investigated by air flow. People being under an exit of air in the indoor air-conditioner feel more comfortable condition and speed of response to comfort change is relatively fast.

• 한국실내디자인학회논문집
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• 제22권3호
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• pp.164-173
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• 2013

This study starts from the genealogical analysis of the urban public spaces through local history of Seoul which is significantly different from western countries. The analysis targets the discourse on the urban street, the basic unit of urban tissue and the settlement condition in urban life, which defines urban space-structure among the urban public spaces. And this research classifies and categorizes the value recognition and policy value occurred each period. Based on these, this research defines the progress levels of urban public design policy in Seoul as follows. Results Firstly, 1890's and 1900's was the period of development in commerce and industry, which caused congested and crowded streets. The open port policy allowed the experience of the foreign circumstance, and thus the identity of the urban streets and the value of symbolism come to realize among the society. During the Japanese colonization, urban streets put on modernized images through the urban remodeling out of the context according to the colonization policy. The brand-new values such as publicness and amenity are injected as well as modern regulations by system and authority. From Liberation to 1950's, it performed only street restoration as a repair from war with Japanese colonial system because of the political confusion and administrative vacuum. Finally, each period can be defined as follows. 1890's and 1900's can be defined as 'spontaneous finding the modernization' because urban street was intentionally transformed by the empire. Period of the Japanese colonization can be defined as 'the formation of modernized urban street concept and the compulsion of modernized regulation.' And period of from Liberation to 1950's, can be called as 'the absence of value recognition and maintenance of colonial system.' methodology.

• 한국환경복원기술학회지
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• 제8권2호
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• pp.83-89
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• 2005

The historical changes of seeding work in Japan, the typical slope revegetation method, is possible to divide into five periods as follows; 1) The early period after creation(1927-1948) 2) The spreading period of modern revegetation work with manpower(1947-1958) 3) The spreading period of rapid revegetation technique using exotic grasses with machineries(1959-1985${\dots}$) 4) The spreading period of rapid reforestation technique by fast growing species mainly using leguminous shrub species(1986-1995${\dots}$) 5)The developing period of nature restoration technique using endemic arborous species(1996-) The evaluation basis of vegetated condition after slope seeding has been described to a official guide book, "The Standards of Slope Stabilizing Works" It was mainly revised three times after first edition in 1972, and also the point of evaluation basis changed from the vegetation coverage to the density of woody plant through the 3rd period and the 4th period Recently main purpose of slope seeding has been developing from the erosion protection to the nature restoration in the current of the 5th period, and "The tentative guidelines of slope nature restoration" was announced by The Slope Revegetation Section of Japanese Society of Revegetation Technology in 2004. It was proposed the planning techniques of using suitable seeds/plants based on the preservation level at the real each construction sites Consequently, at present the importance of advanced monitoring methods for vegetation maintenance and plant sociologic survey to evaluate the plant succession is increasing.

• 한국조경학회지
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• 제30권6호
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• pp.79-97
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• 2003

The purpose of this paper is to analyze a causal model determining social carrying capacity(SCC) in natural parks, to answer the research question: What is the mechanism for determining SCC in natural parks (NP)\ulcorner After reviewing the literature on SCC and recreation activities in Korean natural parks, we constructed a conceptual framework and formulated the hypothesis of this research. We obtained data through a questionnaire which surveyed 487 visitors at 6 of the 73 NP in Korea during 2001, based on a stratified sampling method. We analyzed the data using descriptive statistical methods, the mean difference test, Pearson's correlation analysis, and path analysis method. We found that 1) The direct effect of resources, activity space(AS), visitor's expectation(VE), encounter, crowding, damage of resources(DR), maintenance condition of resources and facility(MCRF) to SCC are 3.45, 3.62, 2.75, 2.72, 1.32, and 4.77 times more important than that of crowding, respectively, while the indirect effect of resources, AS, VE, encounter, and DR to SCC is 13.03, 11.19, 3.34, 1.3, 2.05, 1.10, 0.05 and 2.30 times more important then that of crowding, respectively, 2) Causal effects of resources, facility, AS, VE, number of visitors(NV), encounter, crowding, VM, DR, and MCRF to SCC turned out to have 0.3523, 0.3321, 0.1751, 0.1465, 0.0307, 0.0762, 0.0604, -0.0510, -0.1177 and 0.2165, respectively, and 3) The causal effect of activity base(AB) and activity atmosphere(AA) to SCC turned out to have 2.57 and 1.1 times higher than that of MCRF, respectively. The research results suggest that 1) this conceptual framework is highly useful for the development of substantive theory and methodology; 2) management issues of AA and MCRF turned out to have 0.81 times in SCC that of AB, i.e, SCC can be significantly improved from control of AA and MCRF; and 3) supply of excellent resources and convenient facilities is needed to increase social carrying capacity. It is recommended that more empirical studies be performed in the future according to the season, visitor characteristics, and AS by NP.

• 한국지역사회생활과학회지
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• 제24권2호
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• pp.251-258
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• 2013

Korean oil and honey Yukwa has been paid attention as formal cake for traditional national seasons' holiday and religious service. Quality of Yukwa, however, has been maintained arbitrarily by each Yukwa manufacturer. Since even same Yukwa had severe differences in size, weight, and pattern, it has given the negative effect to the consumer. Yukwa industries need to setup the quantitative quality specifications instead of qualitative ones to maintain the uniformity of Yukwa quality. Efficient and economical inspection and process control system should be developed. In developing quality standards of Yukwa, features which can measure quality quantitatively in real time should be properly chosen. Existing quality features such as acidity, oxidization, hardness, viscosity, and texture were measured by the chemical or physical base destructive methods. Many research and developments have been performed in investigating and analyzing chemical transition states of those quality features as environment or storage condition changes. Most methods, however, require either off-line or complex treatment or time consuming process of analysis in evaluating quality features. Consumer, however, selects products mostly based on the external features such as shape, size, and color. Therefore, critical visual quality features should be chosen and the efficient real time measurement system must be developed. In this paper, computer image acquisition and processing system were developed and software modules were developed to extract the quantitative data of those features in real-time. Computer image processing system will promote in maintaining uniform quality of Yukwa and establishing quality standards of Yukwa.