• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
• /
• pp.1180-1183
• /
• 2003

170kV GIS(Gas Insulated Switchgear) is widely used in large industrial factory-electrical facilities of private use because has many benefits. But Other equipments's failures are occurred by GIS failures and give rise economic problems to user. Therefore we will examine the actual condition of the 170kV GIS-electrical facilities of private use and are able to confirm the distribution characteristic analysis of disconnecting switchgear. In this paper, we presents the actual condition investigation of the disconnecting switchgear of 170kV GIS-electrical facilities of private use by post - failure pattern, inspection method, test equipments and so forth.

• 한국측량학회지
• /
• 제38권5호
• /
• pp.455-465
• /
• 2020

As cities continue to expand and additional underground structures are constructed, a policy is being planned to expand addresses, which are national framework data. In this study, the application scope of a proposed 3D (three-dimensional) mixed-use complex space for assigning 3D addresses was defined, based on past research on 3D address systems and by analyzing related laws. Underpass shopping malls, underground walkways (excluding underground shopping malls), and 3D mixed-use transfer centers with a gross floor area of 2,000㎡ or more are connected with each space by underground walkways or public paths. In addition, the detailed space corresponding to the public space of the 3D mixed-use complex space was presented and distinguished from the space to which the detailed address is assigned. The criteria for setting the road section were presented based on the intermediate space, which is a characteristic of 3D mixed-use complex spaces. The proposed criteria were applied to the Express Bus Terminal station (3D mixed-use transfer center) and COEX mall (underpass shopping malls). Thus, the road section was set for an unfamiliar 3D mixed-use complex space. However, by applying the proposed criteria to various 3D mixed-use complex spaces, additional and detailed criteria for different cases should be prepared.

• 동력기계공학회지
• /
• 제21권6호
• /
• pp.56-61
• /
• 2017

The check valves are mechanical valves that permit fluids to flow in only one direction, preventing flow from reversing. It is classified as one way directional valves. There are various types of check valves that used in a marine application. A lift type check valve uses the disc to open and close the passage of fluid. The disc lift up from seat as pressure below the disc increases, while drop in pressure on the inlet side or a build up of pressure on the outlet side causes the valve to close. An important concept in check valves is the cracking pressure which is the minimum upstream pressure at which the valve will operate. On the other hand, optimization is a process of finding the best set of parameters to reach a goal while not violating certain constraints. The AMESim software provides NLPQL(Nonlinear Programming by Quadratic Lagrangian) and genetic algorithm(GA) for optimization. NLPQL is the implementation of a SQP(sequential quadratic programming) algorithm. SQP is a standard method, based on the use of a gradient of objective functions and constraints to solve a non-linear optimization problem. A characteristic of the NLPQL is that it stops as soon as it finds a local minimum. Thus, the simulation results may be highly dependent on the starting point which user give to the algorithm. In this paper, we carried out optimization design of the check valve with NLPQL algorithm.

• 대한기계학회논문집A
• /
• 제33권10호
• /
• pp.1029-1037
• /
• 2009

Recently, the technologies of mobile robots have been growing rapidly in the fields such as cleaning robot, explosive ordnance disposal robot, patrol robot, etc. However, the researches about the autonomous underwater robots have not been done so much, and they still remain at the low level of technology. This paper describes a model of 3-joint (4 links) fish robot type. Then we calculate the dynamic motion equation of this fish robot and use Singular Value Decomposition (SVD) method to reduce the divergence of fish robot's motion when it operates in the underwater environment. And also, we analysis response characteristic of fish robot according to the parameters of input torque function and compare characteristic of fish robot with 3 joint and fish robot with 2 joint. Next, fish robot's maximum velocity is optimized by using the combination of Hill Climbing Algorithm (HCA) and Genetic Algorithm (GA). HCA is used to generate the good initial population for GA and then use GA is used to find the optimal parameters set that give maximum propulsion power in order to make fish robot swim at the fastest velocity.

• 감성과학
• /
• 제11권3호
• /
• pp.375-385
• /
• 2008

본 연구에서는 인간의 제품에 대한 이미지 연상과 관련된 인지 반응 특성을 파악하고, 제품 선호도 및 경험과의 상관관계 분석을 목적으로 하였다. 이를 위하여, 휴대폰과 제안형 제품사진을 실험자극으로 선정하여, 연상되는 감성어휘를 표현하는 실험과 각 제품사진의 선호도를 평가하는 실험을 진행하였다. 실험 결과로부터 두 가지 결론이 도출되었다. 먼저, 사용 경험이 있는 제품에 대한 언어적 지각 반응에서는 비유 언어와 정서적 이미지의 표현을 혼용하며 선호도 수준이 높아짐에 따라 정서적 표현의 적용이 많아진다. 두 번째는, 제품의 비사용 경험은 선호도와 관계없이 인지 대상을 단지 지각적으로 이해하고 자신의 일반적 경험 정보와 유사성을 고려하여 대응시키는 반응을 유발한다.

• 조명전기설비학회논문지
• /
• 제27권10호
• /
• pp.93-100
• /
• 2013

Generally, the conventional battery charging system using an analog method has the large, heavy hardware and low efficiency. Also, it has the disadvantage that it is necessary to replace the control circuit on the basis of the characteristic curve of the specific battery cell. The proposed programmable digital LLC resonant charging system use high efficiency control system(CC-CV), and has characteristic a small hardware and advantage that a digital programming of the voltage, current, and battery capacity characteristics can be flexible. The system proposed the use of Half-bridge LLC resonant converter is possible to improve efficiency and reduce switching losses by using ZVS topology. Further, a constant voltage - constant current(CC-CV) control algorithm apply to the charger which using a buck converter. The performance of the proposed system is demonstrated through experiments.

• 한국레이저가공학회지
• /
• 제11권1호
• /
• pp.32-35
• /
• 2008

In the remote welding system using $CO_2$ laser, laser beam can be rapidly transferred to a workpiece by moving mirrors of scanner system. So, it makes reducing the cycle time of welding process. We can also use and apply various patterns of weld beads by linear controlled mirrors. But most of the domestic car makers have usually applied use stitch-shaped weld bead. In that case, we don't have the merit of remote welding system efficiently. Therefore, in this paper, we investigated the characteristic of weld strength according to patterns of weld bead on $CO_2$ laser welding. And we also studied the relationship between shape of weld bead and value of tensile load.

• 한국멀티미디어학회논문지
• /
• 제17권12호
• /
• pp.1511-1520
• /
• 2014

After 2011, with the spread of smart devices, large interfaces using the architectural space elements here and there in the cities. Recently the desire for the data has increased, and, following the increase of the range of use by the users, the communication utilizing various forms of interfaces is expected to become more active. In the past, certain range of architecture or parts of the facilities were as the interfaces, but, recently, the development of media technology and the display of various contents forced the utilization of many elements of architectural space in the interface aspects that were not used in the past. Accordingly, the research compare the relationship of the purpose, media environments, interface technology, data form and so on and consider the characteristic of what elements of architectural space are used in order to analyze the characteristic of interfaces used in digital art works. Especially,the research will consider the possibility of commercializing the trends in the interfaces of digital art works in the mediation region of city information services, and propose how to apply such possibility.

• 한국수학교육학회지시리즈D:수학교육연구
• /
• 제5권1호
• /
• pp.13-24
• /
• 2001

Using computer technology in teaching school mathematics creates new instructional environments. The emphases on the use of computer technology in the classrooms and in particular the use of computer-based exploration as a context of mathematics instruction have been reflected in the recommendation of the NCTM (Curriculum and Evaluation Standards for School Mathematics, 1989). Although the power of using computer technology in the exploration of mathematical problems has been recognized and stressed by many educators, we do not have many research studies on mathematics in computer-based explorations. Especially research has failed to clarify how computer technology can contribute to the construction of procedural and conceptual knowledge of mathematics. Up to now most researches on procedural and conceptual knowledge in computer environments have only focused on classifying programming languages which program language has more random access and rich interrelationship characteristic in relation to conceptual knowledge in humans, and which computer language has more characteristic flavor of procedural knowledge. How computer-based explorations affect the knowledge construction of mathematics, therefore, emerges as an issue of research on teacher education program for theoretical framework. This situation leads to do research on the effectiveness of using computer explorations in pre-service teacher education in terms of procedural and conceptual knowledge construction.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1649-1654
• /
• 2009

Induction motors widely use in industry because structure is simple and hard and cost is generally cheap and they are easy to control. In recently, because of saving steel, ventilation and benefit of frame fixing, rectangular core type induction motors use in industry more and more. This paper presents current characteristic according to stator core cutting degree in three-phase induction motor (IM) with rectangular stator core. According to stator cutting degree, magnetic saturation and paths of flux are changed. Because of these situations, phase currents are unbalance and are produced harmonic components and they cause decrease of efficiency. We analyze each $10^{\circ}$ from $0^{\circ}$ to $30^{\circ}$ using 2-D finite element analysis (FEA). Optimal stator cutting core degree selection supplies stable currents and efficiency improvement. In this paper, loss separation test was executed by IEEE Std. 112-98 Method B and we compare with the result of loss separation by Simulation using FEM and by Experiment.