• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1231-1236
• /
• 2008

Since the bi-modal tram is too long so that the traditional steering system controlled only the first axle increases its turning radius, it is not suitable to the domestic road environment. In addition, it become hard to make fine parking with the traditional steering system. To resolve the problem, the bi-modal tram requires an all wheel steering system (AWS) that the second axle is controlled by the first axle's degree and the velocity of vehicle, and the third axle is steered by the articulation angle's degree and the velocity of degree. This paper addresses the factors for the AWS ECU design, the strategies to solve the problems, the core technologies for the implementation, and also the outcomes and analysis of the performance evaluation of implemented system.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2023.07a
• /
• pp.371-372
• /
• 2023

본 논문에서는 대규모 언어 모델(Large Language Models)을 기반으로 한 입학 상담용 챗봇을 설계하였다. 입시 전문 LLM은 Polyglot-ko 5.8B을 베이스 모델로 대학의 입시 관련 데이터를 수집, 가공한 후 데이터 증강을 하여 파인튜닝 하였다. 또한, 모델 성능 향상을 위해 RLHF의 후 공정을 진행하였다. 제안 챗봇은 생성한 입시 LLM을 기반으로 웹브라우저를 통해 접근하여 입시 상담 자동 응답 서비스를 활용할 수 있다.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.1
• /
• pp.47-55
• /
• 2011

The purpose of this study was to perform a kinematic analysis of Harai-goshi(hip throw) in superior female judo players. From our analysis, it appeared desirable for the player to shorten the duration of the technique for maximum results. It was also desirable for the player to draw the opponent backward while simultaneously maneuvering her close to her own body. A turning movement of the body toward the left side was found to be required for the technique, during which the player must lower the position of the center of gravity. During the subsequent angular change of the elbow, the player winds the elbow and, by moving the left shoulder, pulls the opponent toward her. The player lowers the body center by bending the left knee and letting the right knee extend, while turning the upper body and bending the hip joint. The player then draws the opponent in, contacts the opponent closely, turns, and stretches the right knee and hip joint rapidly and concisely, completing the move; it was also found to be desirable for the angular velocity to be increased for maximum efficacy.

• Analytical Science and Technology
• /
• v.33 no.1
• /
• pp.49-57
• /
• 2020

Controlling the quality of indoor air is important in order to maintain a healthy life. In this study, we investigated the correlation between the hazardous substance concentration of indoor air and circulation based on different ventilation methods in the apartment, which is one of the representative housing types in Korea. As target substances, we considered the hazardous substances which are generated during the cooking process and radon gas which is originated from building materials. We measured the concentrations of carbon dioxide and fine particles in relation to type of food and ventilation methods in order to determine the change in the concentration levels of hazardous substances which are generated during the cooking process. On the other hand, we measured the concentration of radon gas before and after letting fresh air into a room through windows in order to determine the change in the concentration level of radon gas which is originated from building materials. The results show that turning on the ventilation fan plays a major role in reducing the concentration levels of hazardous substances in the kitchen, and that it is more effective to turn on the ventilation fan during cooking than after cooking to prevent the diffusion of hazardous materials produced by cooking through the indoor air. Also, the results indicate that letting fresh air into a room through windows more than one time a day is necessary to reduce the concentration level of radon gas in the room to safe concentration range.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.13 no.1
• /
• pp.92-99
• /
• 2014

An aspherical lens, which resolves several problems with a spherical lens,typically serves asa key part of an optical system. Generally, an aspherical lens is fabricated using a diamond turning machine or by mean of injection molding. However, residual stress and/or tool marks can arise when using a commercial fabricating method such as DTM or injection molding. A polishing process, thus, is commonly used to obtain a high-precision aspherical lens. In this study, a polishing method using MR fluid was applied to minimize several problems, in this case residual stress and the creation of tool marks, during the cutting process. The MR polishing system was developed to polish aspherical lenses. A series of experiments were performed to obtain a very fine surface roughness. PMMA (the lens material for molding) was used as a workpiece, and the gap size, magnetic field intensity, wheel speed and feed rate were selected as the parameters in this study. Finally, a very fine surface roughness of Ra=2.12nm was obtained after MR polishing.

• Nuclear Engineering and Technology
• /
• v.38 no.8
• /
• pp.697-732
• /
• 2006

In this paper, a historical review of the developments in the safety of LWR power plants is presented. The paper reviews the developments prior to the TMI-2 accident, i.e. the concept of the defense in depth, the design basis, the large LOCA technical controversies and the LWR safety research programs. The TMI-2 accident, which became a turning point in the history of the development of nuclear power is described briefly. The Chernobyl accident, which terrified the world and almost completely curtailed the development of nuclear power is also described briefly. The great international effort of research in the LWR design-base and severe accidents, which was, respectively, conducted prior to and following the TMI-2 and Chernobyl accidents is described next. We conclude that with the knowledge gained and the improvements in plant organisation/management and in the training of the staff at the presently-installed nuclear power stations, the LWR plants have achieved very high standards of safety and performance. The Generation 3+LWR power plants, next to be installed, may claim to have reached the goal of assuring the safety of the public to a very large extent. This review is based on the historical developments in LWR safety that occurred primarily in USA, however, they are valid for the rest of the Western World. This review can not do justice to the many fine contributions that have been made over the last fifty years to the cause of LWR safety. We apologize if we have not mentioned them. We also apologize for not providing references to many of the fine investigations, which have contributed towards LWR safety earning the conclusions that we describe just above.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.17 no.5
• /
• pp.959-968
• /
• 2022

In this paper, we intend to develop a cart with the convenience of moving objects or items that are difficult to hold by the hand of the disabled and the elderly from outdoor activities to a moving location. Using GPS module, DC motor, Bluetooth module, magnetometer sensor, and Blynk application, the smart follow cart was programmed to accurately know the owner's location while following the cart. The values of latitude and longitude of the magnetometer sensor are set so that the correct leverage value can be obtained in the lead for fine adjustment of the start and stop angles so that the user's position can be freely detected. The above motor driver L298n was connected to the motor to drive the DC motor at a fine angle. A smart follow cart was implemented that receives location signals according to the direction of the owner by turning on/off the mobile phone app as a switching role by connecting the GPS through Bluetooth wireless communication using a smartphone.

• Journal of Welding and Joining
• /
• v.32 no.6
• /
• pp.22-28
• /
• 2014

Most publications on friction stir welding describe phenomena or results with given process parameters like feed rate, rotation speed, angle and depth of penetration. But without a complete documentation of tool design, the results under the same process parameters are completely different. For this purpose, the Institute of Cutting and Joining Manufacturing Processes (tff), University of Kassel investigated the influence of tool roughness on the friction stir welding process. Therefore a defined surface finish was produced by turning and die sinking. As basis of comparison the constant parameters were rotation speed, feed rate, tilt angle and a heel plunge depth. Sound butt-welds were produced in aluminium alloy 6082 (AlMgSi1) with 1.5 mm sheet thickness with a turned reference tool with a surface of $Ra=0.575{\mu}m$ in position controlled mode. The surfaces are manufactured from a very fine to a very rough structure, classified by the VDI-classes with differences in the arithmetical mean roughness. It can be demonstrated with the help of temperature measures, that less heat is generated at the surfaces of the shoulder and the pin by the higher roughness due to lower active friction contact surface. This can also be seen in the resulting wormhole defects.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.818-821
• /
• 2004

With a rapid development in the area of micro and ultra precision technology, the micro surface machining of small size parts are explosively increased. Especially, to improve efficiency of various beams in lens and reflector, non-rotational symmetric form and several mm level heights changeable surface can be machined at a time. These geometric complex 3D surface cannot be machined by general short stroke FTS. The long stroke FTS if firmly needed to move directly several mm and have nm level positioning accuracy for the complex surface form. The long stroke FTS used linear motors to drive moving unit long and fine, aero static bearings to decrease friction and moving errors in guide way, optical linear scale with nm level resolution to measure position of FTS. Furthermore, to increase the performance of acceleration of FTS, the light material, such as AL is used for the structure and the high stiffness box type structure is selected. In this paper, the genetic algorithm approach is described to determine a set of design parameters for auto tuning. The authors have attempted to model the design problem with the objective of minimizing the error, such as variable pattern change. This method can give the better alternative than existing other method.

• Korean Institute of Interior Design Journal
• /
• v.17 no.1
• /
• pp.84-92
• /
• 2008

In the Relationship between exhibition space and art work in museum, new paradigm has being presented from 1990' s as a turning point. Even if the formal exhibition space that emphasizes itself as a background has currently being continued, the informal exhibition space is coming to the new art museums, especially after 1990's. This study is to understand how the advent of informal form of space in an exhibition of art museum makes a new paradigm in the relation between the exhibition space and art work in conjunction with public's perception after 1990' s that is identified to the time of Pluralism. To do this, the study raised a question on how the public perceive the relation between space and art work through photographs that contain the information on relation between space and art work. And the questionnaire performed through the curators who are working for art museum, students who studies fine art, students who studies design and public who comes to art museum. After survey through this questionnaire, it is made clear that the informal form of space simply has played a role of background since the beginning of art museum. In other hands, the informal form of space that is mainly presented after 1990' s begins to interrupt the public's perception of art work, changing it's meaning through a spatiality.