• 산업경영시스템학회지
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• 제40권3호
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• pp.138-147
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• 2017

As the functions and structure of the system are complicated and elaborated, various types of structures are emerging to increase reliability in order to cope with a system requiring higher reliability. Among these, standby systems with standby components for each major component are mainly used in aircraft or power plants requiring high reliability. In this study, we consider a standby system with a multi-functional standby component in which one standby component simultaneously performs the functions of several major components. The structure of a parallel system with multifunctional standby components can also be seen in real aircraft hydraulic pump systems and is very efficient in terms of weight, space, and cost as compared to a basic standby system. All components of the system have complete operation, complete failure, only two states, and the system has multiple states depending on the state of the component. At this time, the multi-functional standby component is assumed to be in a non-operating standby state (Cold Standby) when the main component fails. In addition, the failure rate of each part follows the Weibull distribution which can be expressed as increasing type, constant type, and decreasing type according to the shape parameter. If the Weibull distribution is used, it can be applied to various environments in a realistic manner compared to the exponential distribution that can be reflected only when the failure rate is constant. In this paper, Markov chain analysis method is applied to evaluate the reliability of multi-functional multi-state standby system. In order to verify the validity of the reliability, a graph was generated by applying arbitrary shape parameters and scale parameter values through Excel. In order to analyze the effect of multi-functional multi-state standby system using Weibull distribution, we compared the reliability based on the most basic parallel system and the standby system.

• 한국실내디자인학회논문집
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• 제21권1호
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• pp.95-102
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• 2012

This study analyzed the observation characteristics with the subject of observation data through defining the change of the observation degree as attention /conscious observation /visual understanding. Furthermore, by obtaining the formular with which to estimate the subjects' observation amount, this study suggests a potential method for easier analysis of observation characteristics. The conclusions from the study are as the followings. First, the observation frequency was being generated with wide deviation among subjects while there was a flow-on characteristics depending on the degree of observation. These characteristics enabled the study to obtain the formular with which to estimate the observation amount. Second, the study could establish the area frequency by grade from the entire observation data. The area I was at most 4% for the area frequency but accounted for 18.2% of the entire effective observation time, and the area II 16% and 38.7% respectively. Accordingly, only considering the observation area distribution of the area I or the areas I and II shows which position of the space the subjects were observing. Third, with the subject of the relatively higher observation time at at the subject's observation characteristics, as the observation phase was getting higher, the observation time decreased more. Forth, by obtaining the formular to estimate the observation amount for observation data according to the change of observation degree, the study could find the estimating observation characteristics of additional subjects. The formular shortens the analysis time and facilitates the analysis process.

• 천문학회보
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• 제40권1호
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• pp.60.1-60.1
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• 2015

High energy photons and mechanical energy produced by the process of star formation result in copious FIR molecular and atomic lines, which are important coolants of the system. Photons thermally or mechanically induced could dissociate water in the dense envelope to change relative abundances among the species of O, OH, and H2O. Here we analyze OH emission lines toward embedded young stellar objects (YSOs) observed as part of the Herschel open time key program, 'Dust, Ice, and Gas In Time (DIGIT)' in order to study the physical conditions of associated gas and the energy budget loaded on the OH line emission. According to our analysis of the Herschel/PACS spectra, OH emission peaks at the central spaxel in most of sources, but several sources show spatially extended emission structures. In the extended emission sources, the distribution of OH emission is correlated with that of [OI] emission and extended along the outflow directions. Considering the diversity of source properties, ratios between detected OH lines are relatively constant among sources. In addition, each OH line has strong correlation with bolometric luminosity. In order to determine the physical conditions of YSOs, we adopt several methods for the analysis of the OH lines: rotational diagram, non-LTE LVG analysis, and a 2-D PDR code. From the simple LVG analysis, we find that the thermal solution with the dense ( > $10^7cm^{-3}$) and warm ( ~ 100 K) OH gas reproduces the ratios of detected OH lines. However, our self-consistent PDR 2-D model, which can deal with the IR-pumping effect from the central protostar as well as the warm dust in situ, cannot fit the observational results, suggesting that an irradiated shock model is necessary for a better interpretation.

• 한국전자통신학회논문지
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• 제11권5호
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• pp.441-450
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• 2016

국제전기통신연합(ITU) 전파규칙(Radio Regulation)에서는 인공적인 유도 없이 공간에 퍼져나가는 3000GHz이하의 주파수를 전자파라고 정의하고 있으며, 우리나라도 국제 정의를 따르고 있다. 전파는 인공적인 유도 없이 공간에 퍼져 나가는 전자파로서 ITU가 정한 범위안의 주파수를 가진 것을 말한다. 이중 업무를 분배한 주파수는 300GHz까지인데, 분배된 주파수 중에서도 우리가 매일 접하는 생활용 주파수 대역의 90% 이상이 3GHz 이하이다. 전파는 송신설비 만 갖추면 누구나 생성해 낼 수 있는 것으로 고갈 없이 무한정 발생할 수 있지만, 주파수의 전파를 동일한 시간과 공간에서 이용하게 되면 혼간섭이 발생하게 되어 전파자원을 이용할 수 없게 된다. 이러한 이용 상의 물리적 유한성으로 인해 우리나라에서는 1961년 처음으로 전파관리법을 제정하여 전파자원을 국가가 관리하도록 하고, 권리를 부여받은 경우에만 전파를 이용할 수 있도록 규율하고 있다.

• KIEAE Journal
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• 제15권5호
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• pp.107-112
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• 2015

Purpose: This study desires to investigate an effect of indoor temperature, humidity, and illuminance targeting a planting system of double-skin facade and cavity space adjacent to the outside within a certain period of winter. Through this, the study suggests a basic material about an energy conservation effect of double window system using planting to reduce heating load of a building in winter, so desires to contribute to indoor thermal comfort effect and illuminance correction study of double window and indoor plant. Method: Considering effects such as day and night climatic elements and air conditions in winter, illuminance measurement was conducted through a double-skin facade of space, a subject of the measurement, on the basis of practical residence time of a resident, and this study analyzed characteristics of indoor illuminance about this. The study measured and compared a change of insolation, dry-bulb temperature, and relative humidity at each indoor-outdoor measuring point, so measured and compared characteristics of an indoor temperature effect by elements of double-skin facade and indoor plant. Result: Through this study, the researcher could determine that indoor plant within double window in winter not only blocks solar radiation but also photosynthesizes, so is somewhat disadvantageous to winter thermal comfort reducing heating load. In addition, solar radiation going through interior plays a role to bring down somewhat high humidity to about 50% of reasonable humidity, so plays a direct role of maintenance of comfortable indoor space. Although there are effects such as blocking of solar radiation and temperature reduction, this has a positive influence on humidity control and proper illuminance distribution. The researcher could determine that illuminance, temperature, and humidity by solar radiation penetration for the whole measuring time play a role to supplement indoor environment mutually.

• 정보보호학회논문지
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• 제33권2호
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• pp.223-233
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• 2023

Gauss Sieve는 격자 기반 문제 중 하나인 SVP를 풀기 위한 알고리즘으로 지수 시간 및 공간 복잡도를 필요로 한다. 알고리즘의 종료 조건은 공간 복잡도와 관련이 있는 리스트의 크기 및 충돌 횟수에 의해 결정된다. 여기서 충돌이란 샘플링 된 벡터에 대한 축소 연산 뒤 이미 리스트에 존재하는 벡터와 동일한 벡터가 되는 상황을 의미하며 일정 횟수 이상의 충돌이 발생할 경우 알고리즘은 종료된다. 기존 알고리즘으로부터 제시된 공간 복잡도를 기준으로 실제 실행 결과를 확인하였을 때, 가장 짧은 벡터를 발견한 이후에도 불필요한 연산이 지속되는 것을 확인하였다. 이는 기존의 종료 조건이 필요 이상으로 크게 설정되었음을 의미한다. 따라서 본 논문에서는 불필요한 연산이 반복되는 지점을 파악한 뒤 기존에 필요로 하는 연산의 횟수에 대한 최적화를 진행한다. 종료 조건이 되는 충돌의 임계값과 샘플 벡터가 생성되는 분포를 조정하는 방식으로 실험을 진행하였으며 실험 결과 가장 큰 비중을 차지하는 축소 연산은 62.6% 감소하였으며 이에 따른 공간 및 시간 복잡도는 각각 4.3%, 1.6% 감소하였다.

• Journal of Chest Surgery
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• 제18권4호
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• pp.822-834
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• 1985

Reexpansion of the lung is the most desirable method of filling the pleural space whether it`s contents may be, and closed thoracotomy connected to a water-seal drainage remains the basic therapeutic modality in the treatment of the problems of the pleural space. We usually used rubber mushroom tubes, size No. from 16 to 34 Fr., and performed closed thoracotomy after preliminary thoracentesis to determine the exact depending position. Author reviewed 576 cases of closed thoracotomy which were performed in the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital, since Jan., 1980 to June, 1984. The results were as follows: 1. The age distribution was 10 days to 76 years old and mean age of the patients was 36.6 year, and the most prevalent age group was twenties, and sex predisposition was male dominant, 86.9%. 2. The most common etiologic disease group was pneumothorax and the most common etiologic disease was traumatic hemothorax. 3. Sites of tubing were predominantly at posterior axillary line, 7th intercostal space and midclavicular line, 2nd intercostal space even though frequent presence of free pleural space. The two sides, right and left difference of occurrence rate was more frequent at right side, 51.2%. 4. Usually the durations of tubing was less than 10 days, 52.6%, and the number of tubes used to the same patient concomitantly was one, 73.9%, and the time of tubing to the same patient was 1st, 83.6%. 5. The common symptom and sign were dyspnea, 50.0%, chest pain, 30.7%, cough, 10.7%, fever, 6.5%. Especially, fever and cough was the most common symptom and sign in pyogenic empyema, 59.3%. 6. The common etiologic lesions of pneumothorax were blebs and bullae, 73.3%, and of pyogenic empyema was pneumonia, 69.0%. 7. The complication rate of closed thoracotomy was 26.0%. Among these complications, infection was 44.7%, and intercostal neuralgia was 25.3%. 8. 70.9% of all patients recovered with only closed thoracotomy and the rest of patient needed additional some necessary managements such as open thoracotomy [Blebectomy, Resection, Pleurodesis, Decortication, Bleeding control], open drainage, thoracoplasty and so on to have successful results.

• 항공우주시스템공학회지
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• 제18권3호
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• pp.34-40
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• 2024

저궤도 위성을 포함한 다양한 위성의 궁극적인 운영목표는 촬영된 위성영상을 사용자들에게 정확하게 전달하는 데에 있다. 특히, 저궤도 광학 및 레이다 위성을 통해 획득한 지구관측영상은 매우 다양한 분야에서 활용되고 있으며, 우주산업분야에서 매우 큰 축을 담당하고 있다. 특별히, 사용자 요청부터 영상배포까지의 소요시간은 위성영상 활용가치의 주요 단위이며, 배포소요시간의 단축을 위하여 다양한 기술들이 지상국 시스템에 적용되고 있다. 본 논문에서는 획득영상 주문 배포의 시간을 단축시킬 수 있도록 한국항공우주연구원에서 구축한 주문관리시스템과 데이터시스템사이의 효과적인 인터페이스를 소개한다.

• 한국정보과학회논문지:데이타베이스
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• 제30권2호
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• pp.176-183
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• 2003

질의 최적화에 사용하기 위한 선택도 추정 방법은 히스토그램, 샘플링 그리고 패러미터에 의한 요약 방법 등이 제시되고 있다. 히스토그램을 이용한 선택도 추정은 상용 데이타베이스 시스템에서 가장 보편적으로 사용되는 방법이지만, 이동 객체를 위한 시공간 데이타베이스에서는 데이타 분포가 지속적으로 변화함으로써 기존의 히스토그램 방법을 이용하는 것은 제한이 많게 된다. 특히 미래 질의를 위해서는 데이타 갱신을 반영하는 동적 관리가 가능하며, 정화도를 유지할 수 있는 다른 접근 방법이 필요하다. 따라서 시공간 객체를 위한 선택도 추정 방법은 질의 술어가 요구하는 데이타 분포에 대한 히스토그램이 필요하며, 본 논문에서는 미래의 시공간 영역 질의 술어에 대하여 신속히 히스토그램을 생성할 수 있도록 쌍대성과 한계 분포 방법을 이용한 히스토그램을 제안한다. 쌍대 공간에서 이동 객체에 대한 데이타 시놉시스를 이용하여 구성된 시공간 히스토그램은 이동 궤적의 선형성이 유지하는 시간 동안 정확성을 보장하면서 빠른 시간에 생성이 가능하다. 또한 동적 갱신을 점증적으로 지원함으로써 효율적으로 갱신된 정보를 반영할 수 있고 추정 결과의 정확성을 향상시킬 수 있다.

• 한국유통학회지:유통연구
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• 제1권1호
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• pp.41-63
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• 1996

In spite of economy has a critical cycle such as, production, distribution and consumption, we hardly concentrated our study to distributional system and behavior. Especially in Korea, Traditional idea had tried to ignore the people who work in this economic value at all. Manufacturers, other than retailers and wholesalers, had a belief that the manufacturing can control distributional channels forever. Unfortunately, technological and educational advances caused the quality equalization among developing and developed countries as well as among big and small manufacturers in their products. By this reason, economists are searching the economists dark continet' mentioned by Peter Drucker as a new source of wealth. According to a report by well-known economic research institute in Switzerland, Korea has classified in the lower level group in terms of international compatitive power. At the same time, business firms complain that they are suffering from lack of SOC and infrastructures. As an important mean to overcome the economic bottleneck, economists suggest in improve our distributional atmosphere. Basically, distributional study has two sub-fields as: commercial and physical distributions, Distributional system mainly concerns about to shorten the distances of time and space between production and consumption. The closer the distances, the higher efficiency can be achieved. Building distributional system will cost, but tile results will save social costs. Based on this idea, economists proposed several ways to cut the distances and to save costs, Naturally, they hope their beliefs can be adapted by business firms and governments. But frequently, their theories doesn't make any fruit. This paper has studied about the composition of joint transportational and distributional systems. And, even though there's no Marshall in tile real world at this point authors are trying to define the transportational and physical distributional costs, the most powerful factor that can impact to economic decision making.