• 설비공학논문집
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• 제17권4호
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• pp.370-376
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• 2005

For the purpose of investigating the effective removal of heating/cooling load from light-weighted building envelope, two air-conditioning systems, conventional parameter air-conditioning system and air-barrier system, are evaluated and compared by both experiment and simulation with six different cases during heating and cooling season. In addition, the characteristics of window-side building thermal load are assessed by varying supply air velocity in order to seek the optimal system operation condition. The results are as follows. 1) Air-barrier system is more effective to remove heating/cooling load at perimeter zone than conventional parameter air-conditioning system. Moreover, the better effectiveness appears during cooling season than during heating season. 2) The experiment during cooling season provides that indoor temperature of air-barrier system shows $1^{\circ}C$ less than that of the conventional system with similar outdoor air temperature profile, and indoor temperature distribution is more uniform throughout the experimented model space. It concludes that air-barrier system can achieve energy saving comparing to the conventional system. 3) The capturing efficiency of air-barrier system is 0.47 on heating season and 0.2 on cooling season with the same supply air volume. It results that the system performs effectively to remove building thermal load, moreover demonstrates high efficiency during cooling season. 4) The simulation results provide that capturing efficiency to evaluate the effective removal of building load from perimeter zone shows high value when supply air velocity is 1 m/s.

• 대한방사선치료학회지
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• 제12권1호
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• pp.20-25
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• 2000

The accuracy of the target localization was evaluated by conventional and spiral CT in stereotactic radiosurgerv. Conventional and spiral CT images were obtained with geometrical phantom, which was designed to produce exact three-dimensional coordinates of several objects within 0.1mm error range. Geometrical phantom was attached by BRW headframe, intermediate head ring, and CT localizer. Twentv-seven slices of conventional CT image were scanned at 3 mm slice thickness. Spiral CT images were scanned at 3 mm slice thickness from the pitch value 1 to 3, and twenty-seven slices of image were obtained per each the pitch value. These CT images were transferred to a treatment planning system(X-knife, Radionics) by ethernet, Three-dimensional coordinates of these images measured from the treatment planning system were compared to known values of geometrical phantom. The mean localization error of the target localization of conventional CT was 1.4mm. In case of spiral CT, the error of the target localization was within 1.6mm from the pitch value 1 to 1.3, but was more than 30mm above the pitch value 1.5. In conclusion, as the localization error of spiral CT was increased in high pitch value compared to conventional CT, the application of spiral CT will be with caution in stereotactic radiosurgery.

• 한국전자파학회논문지
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• 제17권12호
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• pp.1164-1171
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• 2006

본 논문에서는 터보 처리 MIMO 시스템에서 시스템의 성능을 향상시키기 위해 기존의 선형 MMSE 검출기를 기반으로 간단한 비선형 MMSE 검출기를 유도하고 가우시안 근사화와 비선형 MMSE 검출기를 갖는 새로운 터보 처리 MIMO 시스템을 제안하였다. 터보 부호를 사용하는 터보 처리 MIMO 시스템에서 기존의 시스템과 제안된 시스템의 프레임 오율 성능을 살펴보면 1 % FER을 기준으로는 송신과 수신안테나 수를 각각 N과 M이라 할 때, M=N=4인 경우 제안된 시스템은 기존의 시스템보다 약 0.5 dB의 성능 향상을 갖고, M=N=8인 경우 제안된 시스템은 기존의 시스템보다 약 0.4 dB의 성능 향상을 갖는다. 또한 평균 외부 반복 횟수를 살펴보면 제안된 시스템이 기존의 시스템보다 낮은 수준을 보여주었다. 제안된 시스템의 비선형 MMSE 검출기가 수신신호의 측정값에 근거하여 부호화된 비트의 연 출력을 결정함으로써 심볼 값을 판정하는데 필요한 영역에서의 불확실한 부분을 줄였기 때문에 성능이 향상될 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.175-178
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• 2003

This paper proposes a stereo image insertion technique on DCT coefficients using the embedded method developed in the digital watermarking in due consideration of compatibility with conventional 2D system such JPEG, and MPEG. In conventional transmission method users with conventional digital TV cannot watch the transmitted 3D image sequence as 2D image, because of affectivity of conventional 3D image compression. To give an answer, in this paper, DCT coefficients are changed according to its disparity on YCbCr channels. Our method can insert stereo images into a conventional image compression method based on DCT.

• 한국자동차공학회논문집
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• 제6권1호
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• pp.90-98
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• 1998

A Dual Mass Flywheel(D.M.F.) system is an evolution to the reduction of torsional vibration and impact noise occurring in powertrain when a vehicle is either moving or idling. The D.M.F. system has two flywh-eels, which is different from the conventional clutch system. One section belongs to the mass moment of in-ertia of the engine-side. The other section increases the mass moment of inertia of the transmission-side. These two masses are connected via a spring/damping system. This reduces the speed at which the dreaded resonance occurs to below idle speed. Since 1984m D.M.F. system has been developed. However, the processes of development of D.M.F. system don't have any difference from the trial and error method of conventional clutch system. This paper present the method for systematical design of D.M.F. system with dimensionless design varia-bles of D.M.F. system, mass ratio between two flywheels, natural frequency rate of two flywheels, and visc-osity coefficient. And expermental results are used to prove these theoretical results.

• 설비공학논문집
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• 제22권6호
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• pp.369-374
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• 2010

A refrigerant-subcooling refrigeration system consisted of a typical single vapor-compression refrigeration cycle, a subcooler, and an ice storage tank. The degree of subcooling at the exit of the condenser can be increased by the heat exchange between the subcooler and the ice storage tank. The cold heat in the ice storage tank was stored by using the refrigeration cycle during night time and then used to absorb the heat from the subcooler during daytime. The performance of the refrigerant-subcooling refrigeration system was measured by varying the degree of subcooling. In addition, the performance characteristics of the present system were compared with those of a conventional refrigeration system. The mass flow rate of the present system was higher than that of the conventional system due to the increase in the degree of subcooling. Generally, the refrigerant-subcooling system showed superior performance to the conventional refrigeration system.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.87-93
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• 2008

The $CO_2$ air conditioning system installed in fuel cell vehicles could be used either for stack cooling or for cabin cooling, and thus was used for the stack cooling when additional stack heat release was required over a fixed radiator capacity for high power generation. This study investigated the performance of the stack cooling system using $CO_2$ air conditioner at various operating conditions. Also, the heat releasing effectiveness and mutual interference were analyzed for the stack cooling system using an air conditioner and compared with the conventional radiator cooling system with/without cabin cooling. The heat release of the stack cooling system with the aid of $CO_2$ air conditioner increased up to 36% more than that of the conventional radiator cooling system with cabin cooling. Furthermore, the heat release of the stack cooling system using $CO_2$ air conditioner increased more by 7% than that of the conventional radiator cooling system without cabin cooling.

• 대한방사선치료학회지
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• 제16권2호
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• pp.25-32
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• 2004

목적 : 모의 치료실에서 환자의 정확한 치료 범위 결정을 위해 이용되는 투시영상은 일부 최신의 고가장비에서는 digital로 capture가 가능하나, 일반적인 simulator에서는 analog영상으로 capture를 할 수 없으며 모니터링만 할 뿐이다. 이번 논제에서는 conventional simulator를 이용한 저가의 Digital image capture system의 구현 방식을 소개하고, capture된 digital 영상을 이용한 임상적인. 실용 증례를 소개하고자 한다. 대상 및 방법 : 본원의 conventional simulator(SIMVIEW NT)용 모니터의 비디오 단자(terminal)에 video signal cable을 연결하여 A/D converter에 연결한다. converter jack을 컴퓨터 capture boar에 연결하고 컴퓨터상의 image capture system을 작동시켜서 원하는 image를 capture하거나 동영상을 녹화한다. Esophagus, cervix, breast 환자 등의 capture image를 상용화된 image processing program을 통해 임상적으로 활용한다. 결과 : 경제적으로 저렴하고 용이한 방법으로 Digital image capture system(DICS)의 구축이 가능하였으며 capture된 영상을 이용하여 simulation시에는 보다 정확한 환자 정보와 치료범위를 결정하는데 도움이 되었고, capture된 영상은 data로써 충분한 가치가 있었다. 결론 : 고가의 상용화된 장비를 구입하기 어려운 경우에 이와 같은 방법으로 저가의 system를 구축하게 되면 경제적 효과와 더불어 고가장비와 동등한 영상의 획득 할 수 있으며, 그러한 과정을 통해 얻어진 영상을 이용하여 다른 software program과 연계한다면 더 많은 임상적인 연구를 할 수 있을 것이라 생각된다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.79-87
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• 2008

The major objective of this study is to investigate the effective maintenance system for the infrastructure on the conventional lines in which the tilting train runs. In order to the speed-up of conventional lines that have many curve lines, there needs a improvement construction of substructure such as the straight or double track work and so on. But in this case, it needs to have a plenty of the cost and the period. Therefore, the tilting train which provides the high-speed service effectively in curve tracks was developed. Besides, the efficiency prediction and the linear fitness of the existing conventional lines for a tiling train service were examined on the preceding study which was the development of track system innovation technology for speed-up of them. So, in this paper we propose the more effective maintenance method than the existing it in order to securing the high reliability and safety classified by the infrastructure, in analyzing foreign materials and the maintenance as well as the inspection cycle concerning domestic infrastructures of the track and the catenary etc. on the railway. And we look forward to playing a decisive role as reference material for the effective improvement of the existing maintenance about the infra on the conventional lines for the commercial service of the tilting train.

• 한국식품조리과학회지
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• 제11권4호
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• pp.370-378
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• 1995

This study is to seek methods for optimum management of foodservice system for elementary schools in Korea through surveying and analyzing the current status of the "common-management foodservice system" and certain important factors relating to its operations. For the survey of the current status of the "common-management foodservice system", questionnaires are prepared as against schools adopting "common-management system"("Common Schools") as well as schools adopting "conventional management system" ("Conventional Schools") in Kyungsangbookdo ("Kyungbook") area. The survey items are composed of general items, items concerning tasks of dietitians, items concerning purchasing activities and items concerning level of recognition and job-satisfaction of the dietitians. Total 46 dietitians from Common Schools and 65 dietitians from Conventional Schools in Kyungbook region responded the questionnaires. The results of this study are as follows: 1. Information Concerning Dietitians Average age of the dietitians: 26.6 yrs Ratio of two years or less of experiences as school dietitian: Dietitians from Common Schools: 59.1％ Dietitians from Conventional Schools: 50.8％ 2. Types of the Foodservice In both schools, rural type are prevalent; however, between urban types and islands types, the ratio of urban types are larger than the ratio of islands types in Conventional Schools, and the opposite is true in Common Schools. 3. Decision of Suppliers The ratio of dietitian＇s participaion in the decision making reaches only 38.3％, indicating the possibility of problems in quality control and hygienic aspects of the food supply. 4. Factor Analysis of the Foodservice Duties Food supply and general affairs administration work was carried out very well (4.2), while personnel management and operational improvement work (2.8), nutritional education work (2.3), and information related work were poorly carried out. No significant differences were found between the two types of the foodservice management systems. 5. Job Satisfaction scores of Dietitians Dietitians were more satisfied with the works (50.0), supervision (50.5) and co-workers (46.9) than pay (18.0) and promotion (22.3).