• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.85-88
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• 2004

Mono-crystalline silicon(mono-Si) is both abundant in our environment and an excellent material for Si device applications. However, single crystalline silicon solar cell has been considered to be expensive for terrestrial applications. For that reason, the last few years have seen very rapid progress in the research and development activities of layer transfer(LT) processes. Thin film Si layers which can be detached from a reusable mono-Si wafers served as a substrate for epitaxial growth. The epitaxial films have a very high efficiency potential. LT technology is a promising approach to reduce fabrication cost with high efficiency at large scale since expensive Si substrate can be recycled. Low quality Si can be used as a substrate. Therefore, we propose one of the major technologies on fabricating thin film Si substrate using a LT. In this paper, we study the LT method using the electrochemical etching(ECE) and solid edge.

• 대한기계학회논문집A
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• 제29권8호
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• pp.1093-1101
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• 2005

Hybrid mass damper systems have recently been introduced as a dynamic vibration absorber to exploit the benefits of both the conventional tuned mass damper system and the active control system. A hybrid system is programmed to function as either a conventional TMD or as an active system according to the wind conditions and the resultant building and damper mass vibration characteristics. This paper deals with the design of the robust controller for the control of the flexible box structure. The control algorithm was devised based on $H_2$(LQG) robust control logic with acceleration feedback and to improve the capability of the controller Kalman Filter was accepted for the system. To test the ability of the robust controller using the linear motor damper system, performance tests and simulations were carried out on the full-scale steel frame structure. Through the performance tests, it was confirmed that acceleration levels are reduced down.

• 한국경영과학회:학술대회논문집
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• 대한산업공학회/한국경영과학회 1991년도 춘계공동학술대회 발표논문 및 초록집; 전북대학교, 전주; 26-27 Apr. 1991
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• pp.67-76
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• 1991

For several years, graduate students and faculty of the Engineering Systems Research Center at U.C., Berkeley have been studying new methods of planning and scheduling in a computer integrated manufacturing environment, with particular emphasis on large scale integrated circuit fabrication. One part of this work, focusing on short interval scheduling, uses simulation models as a primary research tool. We have built two versions of the same basic model (programmed in C) to study two different problems (one deals with machine down time and the other with setup times). These have proven to be efficient for studying particular problems, but are difficult and time consuming to modify. We are convinced that our research will be more effective: (1) if it were easier to build special purpose models tailored to the research question at hand; and (2) if we had better interfaces to graphics output. Commercially available factory simulators are inadequate for this research for a variety of reasons. Existing packages such as SIMKIT, SLAM, SIMAN and EXCELL have their own weaknesses. Typically, they are hard to develop and to modify. They do not allow for adding new dispatching decisions or release decision. Also, it is hard to add more machines to existing environment or change the route the product flows. For these various reasons, we had developed a new simulation package having flexibility and modularity. In this paper, based on experiences gained in the application of object oriented programming, we discuss unique features of the simulator developed in OOPS and ways to take advantage of features in developing and using manufacturing simulation software written in the OOPS

• 대한간호학회지
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• 제34권2호
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• pp.213-224
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• 2004

Purpose: This study was aimed to evaluate the effect of progressive muscle relaxation training using biofeedback on perceived stress, stress response, immune response and climacteric symptoms, Method: This was a crossover, pre-post test design, The study subjects are 36 middle-aged women who were selected at 2 public health centers, The independent variable was Biofeedback training for 4 weeks, twice a week and home training for 4 weeks, Dependent variables were perceived stress, stress response, immune response, and climacteric symptoms measured with Hildtch's scale (1996), Result: Progressive muscle relaxation training using biofeedback was not effective in reducing perceived stress, but it was shown to be effective in reducing physiological stress responses such as pulse rate and EMG, Though blood pressure and skin conductance were repeatedly down, and skin temperature slowly increased, there were no statistically significant differences. Progressive muscle relaxation training using biofeedback was not effective in reducing serum cortisol, enhancing immune responses, or decreasing climacteric symptoms. Conclusion: The findings point to a pressing need for further, well-controlled and designed research with consideration in selection of subjects and instruments, frequency of measurements, the sampling method, and intervention modalities.

• 한국군사과학기술학회지
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• 제12권5호
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• pp.609-614
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• 2009

In this paper, we have proposed a design for security network system passing through the non-security network which is commonly used for various networking services. Based on the security requirements which are assumed that the large classified data are bi-transmitted between a server and several terminals remotely located, some application methods of security techniques are suggested such as the network separation technique, the scale-down application technique of certification management system based on the PKI(Public Key Infrastructure), the double encryption application using the crypto-equipment and the asymmetric keys encryption algorithm, unrecoverable data deleting technique and system access control using USB device. It is expected that the application of this design technique for the security network causes to increase the efficiency of the existing network facilities and reduce the cost for developing and maintaining of new and traditional network security systems.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.803-807
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• 2009

The bobsleigh is a winter sport which use a sled to slide down an ice-covered course. There is a big expectation for having a training environment and being able to train year round. At present, training is very limited due to the season or course facilities. A variety of VR (Virtual Reality) equipment has been developed in recent years, and it is beginning to spread. We have also made our contribution in bobsleigh simulation. The reactive force applied in our bobsleigh simulation is much smaller than that of a real bobsleigh. This paper proposes a method to enhance reactive force of bobsleigh simulation in real time. The reactive force is magnified instantly in the physically-based simulation. The Laplacian filter is applied to the sequence of reactive force, this technique is often used in the field of image processing. The simulation is comprised of four large scale surround screens and a 6-D.O.F. (Degree Of Freedom) motion system. We also conducted an experiment with several motion patterns to evaluate the effectiveness of enhancement. The experimental results proved useful in some cases.

• Journal of Advanced Marine Engineering and Technology
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• 제39권8호
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• pp.821-827
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• 2015

This study concentrates on a wave energy converter with floaters that extracts the ocean's energy by moving up and down with the wave motion. The floater is connected to an arm structure, including a hydraulic cylinder that drives a hydraulic generator. This study focuses on a structural analysis of the floater unit, including arm and cylinder components, platform and jack-up system, along with spud columns. Previous studies have been conducted for miniature models for experimentation, but this study focuses on the full-scale model structural analysis. Static structural analysis is conducted using fine numerical grids. Due to the complexity of the whole model, it is analyzed in separate pieces. The floater unit, with arm and cylinder, are combined into one system. The platform is analyzed separately as a single system. There are four jack-up systems for each spud column; only one jack-up system is analyzed, as uniform loads are assumed on each system. There are several load cases for each system, all of which are analyzed thoroughly for stress (von Mises, shear, and normal) and deformation. Acceptable results were obtained for most of the components; unsafe components were redesigned.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.317-320
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• 2001

본 논문에서는 Si-기반 나노채널 nMOSFET의 문턱전압에 관하여 분석하였다. 본 논문에서 연구된 소자는 180nm의 n-채널 MOSFET을 기준으로 30 nm까지의 게이트 길이를 가진 소사를 정전압 스켈링 이론에 따라 스켈링하였다. 이들 소자들은 드레인 영역에서의 전계크기 감소와 단채널 효과를 줄이기 위해 LDD(lightly doped drain) 구조를 사용하였으며 이들 소자의 문턱전압을 조사ㆍ분석하였다. 이러한 해석은 IC응용의 한계에 대한 분석을 제공할 것이며 VLSI의 기본 데이터로 활용될 수 있을 것이다.

• 한국전기전자재료학회논문지
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• 제18권1호
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• pp.24-29
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• 2005

Chemical mechanical polishing (CMP) has been widely accepted for the global planarization of multi-layer structures in semiconductor manufacturing. Copper has been the candidate metallization material for ultra-large scale integrated circuits (ULSIs), owing to its excellent electro-migration resistance and low electrical resistance. However, it still has various problems in copper CMP process. Thus, it is important to understand the effect of the process variables such as turntable speed, head speed, down force and back pressure are very important parameters that must be carefully formulated in order to achieve desired the removal rates and non-uniformity. Using a design of experiment (DOE) approach, this study was performed investigating the main effect of the variables and the interaction between the various parameters during CMP. A better understanding of the interaction behavior between the various parameters and the effect on removal rate, non-uniformity and ETC (edge to center) is achieved by using the statistical analysis techniques. In the experimental tests, the optimum parameters which were derived from the statistical analysis could be found for higher removal rate and lower non-uniformity through the above DOE results.

• 한국추진공학회지
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• 제12권3호
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• pp.24-33
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• 2008

진공 작동 조건에서 50 Newton 추력 레벨을 가지는 과산화수소 단일추진제 추력기를 개발하였다. 축소형 추력기를 제작하여 제조한 촉매의 추진제 분해 성능을 평가하였다. 축소형 추력기의 성능 평가 결과로부터 50 Newton 추력을 위한 추진제 유량을 완전히 촉매 분해시키기 위해 필요한 반응기를 설계하였다. 스케일 업을 통해 제작된 추력기는 34.8 g/s의 추진제 유량에서 98%의 특성속도 효율을, 대기압 조건에서 42 Newton의 추력, 123 sec의 비추력 결과를 보임으로써 반응기 스케일 업 과정이 적절함을 확인하였다.