• Journal of the Korean Society of Systems Engineering
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• v.10 no.1
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• pp.33-41
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• 2014

New design concept of Reactor Coolant System (RCS) including a reactor assembly for the SMR is introduced in this work. An exploration of new type of reactor that is advanced from proposed SMRs is performed by using systems engineering approach. In this point of view project structured on three main phases; needs analysis (NA), concept exploration (CE), and concept definition (CD). Main objectives as an output of the CE stage are a small size, low cost, shortening the schedule, and enhancing safety. The SMRs usually have a small size requirement. In order to meet the size requirement and to achieve a productivity, in other words, easiness to manufacture, this paper suggests an integrated PWR design concept through researching predecessors. Although the integrated PWR concept provides many advantages, it has disadvantages that composite of maintenance and a low availability problem. Therefore, this paper comes up with a run-to-fail design concept based on modular design to address the maintenance problem and to maximize the availability of SMRs as well as to be compatible with the overall-SMRs including Barge Mounted(BM)type.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.665-666
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• 2006

In precision laser microfabrication, focusing is essential to acquire good machining precision and uniform machining quality. If it does not perform, laser machining cannot be realized. So, confocal scanning method with high depth resolution is used for focus detection technique. This paper is concerned with a procedure for design, analysis and performance test of an autofocus fine actuating stage, which is composed of flexure-hinge type lever mechanism and piezoelectric actuator. Through series of analytical design, the stage is simplified as a rigid bodies(lever and main body) and springs(flexure hinges). The simplified model was applied to determine the dimension of flexure hinges and lever. After structural analysis confirmed design requirement, an actual stage was made and verified through an experiment on the static and dynamic characteristics(maximum stroke and 1st natural frequency). The fabricated stage was satisfied with the design requirement.

• Bulletin of the Korean Space Science Society
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• 2010.04a
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• pp.25.3-25.3
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• 2010

Our previous study used a bar-type reference mirror to measure the relative distance to the target surface. The target measurement accuracy was required to $1{\mu}m$ PV for aspheric optical surface up to 1m in diameter. Earlier system suffers from the reference surface deformation when the measuring part moves. In order to reduce the deformation, measuring part and the reference part separated from each order in the new design. This system utilizes a kinematic support assembly using invar flexure to minimize the reference surface deformation under gravity and vibration. The surface deformation requirement of reference mirror is defined as of $0.2{\mu}m$ under gravity and 40Hz vibration. The finite element results, shows reference mirror deformation of $0.164{\mu}m$. The first resonance mode was computed to analysis 46.05Hz for reference part and 43.44Hz for measuring part. Thesis satisfies the frequency requirement.

• Journal of the Society of Naval Architects of Korea
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• v.58 no.5
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• pp.314-321
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• 2021

In the existing whole ship analysis, topside was modeled as mass element. However recently, the topside is modeled as beam element due to the owner's requirement to improve the maturity of the whole ship FE model. To follow the owner'srequirement, detailed information for topside drawing and modeling, which may delay analysis schedule, is needed. However, it is hard to respond effectively to this matter due to the lack of study on the topside from the hull perspective. Therefore in this study, the effect of the topside on the hull is investigated when the topside is modeled as a mass element or beam element respectively. In addition, the interface modeling method is analyzed to verify modeling method used in the existing whole ship analysis. The results indicate that the interface and topside modeling method used in existing whole ship analysis are appropriate. This conclusion will be the technical basis for responding to owner's requirement about the topside modeling method.

• Journal of Navigation and Port Research
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• v.27 no.3
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• pp.267-272
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• 2003

This paper describes design method of Passive-type Radar Reflector (PRR) which is to provide the requirement of newly revised 2000 SOLAS regulations on the Radar Reflector. The main target of this work is to find the optimum shape of a radar target having large Radar Cross Section (RCS). Through the RCS analysis based on the theoretical approach, two kinds of PRR models, RRR-F model for use in fisheries and PRR-S model for use in small sized ship, are designed and discussed their RCS performance. RCS measurement tests for the various sized samples are carried out in an anechoic chamber. As evaluation results it was clearly shown that the conventional sphere-type shows optimum shape in case of PRR-S, while the cylinder-type which consists of large sized corner clusters or zig-zag flat plats gives best performance in case of PRR-F.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1709-1716
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• 2003

Stirling engine is a heat engine with a high potential efficiency, multi-fuel capability, its low emission, quiet operation, very low maintenance requirement and long life. The Stirling cycle can ideally achieve optimum thermodynamic efficiency of the Carnot cycle. But the actual efficiency of practical reciprocating Stirling engine is much less than that of ideal Stirling cycle due to several mechanical limits. This paper presents a new-type Stirling engine employing the scroll mechanism superior to the reciprocating Stirling engine. The new-type Stirling engine is characterized as traits of continuous and wholly seperated compression and expansion, one-way flow, direct cooling and heating through the extensive surfaces of scroll wraps. By means of this traits, the new-type Stirling engine can achieve thermodynamic cycle closer to the ideal Stirling cycle and have many mechanical merits. Also, the new-type Stirling cycle can be applied as Stirling refrigerator and Duplex Stirling machine.

• Journal of Biosystems Engineering
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• v.15 no.4
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• pp.346-354
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• 1990

In order to provide basic references for the design of heating on simple silkworm rearing house, the actual change of heating load coefficient by progress of adult silkworm rearing day from the reared in silkworm rearing house, the heating load coefficient by types of silkworm rearing houses and the heating requirement and the maximum heating load by types of silkworm rearing houses were determined. The results obtained from the study were as follows : 1. The average heating load coefficients of NS, OS and CC type simple silkworm rearing houses were $24.1KJ/m^2-hr-^{\circ}C$, $19.8KJ/m^2-hr-^{\circ}C$, and $10.8KJ/m^2-hr-^{\circ}C$, respectively. 2. The change of heating load coefficient by progress of silkworm rearing day after reared into simple silkworm rearing house could be expressed as Fig. 4. 3. Heating degree-hour for adult silkworm rearing in Suweon district was calculated as $951.6^{\circ}C-hr$ for spring season and $610.5^{\circ}C-hr$ for autumn season. 4. Yearly heating requirement of the NS type was estimated twice more than that of the CC type. Thus, some kinds of reinforced thermal adiabatic facilities is desirable for NS type. 5. The time for maximum heating load was turned out at the 4th instar during the spring season and after the mounting during the autumn season. 6. This study was performed in Suweon district. However, the estimated and analyzed data could be adapted to the major silkworm rearing district if their meteorology data were adjusted.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.608-613
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• 2007

Fine pitch microprobe arrays are microneedle-like probes for inspecting the pixel of LCD panel. They are usually made of multilayers of metallic, nonmetallic, or combination of the two. In this study, the microprobe arrays were fabricated using the process applied for MEMS fabrication technology and they consist of BeCu, BeNi, or Si. Their contacting probing force and deflection were measured using the laser equipment. The design requirement are 5gf of a minimum contact force and $150{\mu}m$ of a maximum deflection. A lot of microprobe shape are possible satisfying the requirement. A double cantilever-type microprobe having needles on both ends were applied for this study. Several candidate were chosen using the topology and shape optimization technique subjected to the design requirements. Finite element results and experimental results were compared and both gave good correlation.

• Journal of the Korea Society of Computer and Information
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• v.22 no.3
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• pp.35-43
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• 2017

In IoT(Internet of Things) environment, users want to receive customized service by users' personal device such as smart watch and pendant. To fulfill this requirement, the mobile device should support a lot of functions. However, the miniaturization of mobile devices is another requirement and has limitation such as tiny display. limited I/O, and less powerful processors. To solve this limitation problem and provide customized service to users, this paper proposes a collaboration system for sharing various computing resources. The paper also proposes the method for reasoning and recommending suitable resources to compose the user-requested service in small device with limited power on expected time. For this goal, our system adopts MBTI(Myers-Briggs Type Indicator) to analyzes user's behavior pattern and recommends personalized resources based on the result of the analyzation. The evaluation in this paper shows that our approach not only reduces recommendation time but also increases user satisfaction with the result of recommendation.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.479-483
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• 2003

In general, urban railroad in Korea is constructed as a tunnel type under ground due to the various restricted conditions. Passengers in train running through underground tunnel compare to open space are exposed to severe noise environment. In this study, various performance characteristics of many candidate materials are surveyed and analyzed. And some important characteristics are tested. From this study, various performance requirement for noise reduction in railway tunnel were suggested.