• Journal of Korean Association for Spatial Structures
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• v.22 no.3
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• pp.41-48
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• 2022

The purpose of this study is to evaluate seismic performances of a modular house system developed by a simple 4-clip fastening method and double metal assembly made of lightweight metals. In order to evaluate structural and non-structural seismic performances of the system. Shaking table test was carried out with full-scale modular units, and a nonlinear pushover analysis was performed to obtain suitable seismic responses for story drifts, displacements, force resistances and dynamic properties of the system. Through 3D analysis and shaking table test, the current method of lightweight modular metal unit assembly and systems with seismic performance of a 4-clip fastening type modular house were demonstrated safe and effective to seismic design.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.157-159
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• 2017

This paper presents a storage reliability evaluation method based on the accelerated degradation test for the engine assembly and parts of the guided missile. The test of the engine assembly is performed at accelerated conditions equivalent to the real storage period, and then the aging condition of parts is checked. For engine parts, performance degradation characteristics are measured periodically at the accelerated conditions and failure times are predicted at each condition. Storage lifetime at normal use conditions is predicted using an accelerated model and failure times at all accelerated conditions.

• Journal of the Korean Operations Research and Management Science Society
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• v.34 no.2
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• pp.101-111
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• 2009

This paper considers two-sided assembly line balancing with preemptive multiple goals. In the problem, three goals are taken into account in the following priority order : minimizing the number of mated-stations, achieving the goal level of workload smoothness, and maximizing the work relatedness. An evolutionary algorithm is used to solve the multiple goal problems. A new structure is presented in the algorithm, which is helpful to searching the solution satisfying the goals in the order of the priority. The proper evolutionary components such as encoding and decoding method, evaluation scheme, and genetic operators, which are specific to the problem being solved, are designed in order to improve the algorithm's performance. The computational results show that the proposed algorithm is premising in the solution quality.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.4
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• pp.63-71
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• 2003

This paper analyses a deterministic scheduling problem concerned with manufacturing multiple types of components at a pre-assembly stage composed of parallel fabrication machines. Each component part is machined on a fabrication machine specified in advance. The manufactured components are subsequently assembled into products. The completion time of a job(product) is measured by the latest completion time of its all components at the pre-assembly stage. The problem has the objective measure of minimizing the total weighted completion time of a finite number of jobs. Two lower bounds are derived and tested in a branch-and-bound scheme. Also, three constructive heuristic algorithms are developed based on the machine aggregation and greedy strategies. Some empirical evaluation of the performance of the proposed branch-and-bound and heuristic algorithms are also performed.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1355-1360
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• 2003

Currently, product of optical collimator for optical communication is depending on handiwork, and some companies are propelling semi-automatic system composite of manual and automatic operations. In this point of time, the importance of automatic system of optical collimator for optical communication is taking its place as a core technology in the development of parts with high-efficiency of optical communication. In order to develop such an optical collimator in this study, we designed an automatic assembly system, and developed a software for the system operation. At a result of that, we could carry out a single work process individually running processes of collimator fabrication, a constant work process constantly running all of the processes, and performance evaluation of the collimator.

• IE interfaces
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• v.18 no.3
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• pp.297-307
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• 2005

PCB assembly is a complicated and difficult process to optimize due to the necessity of simultaneous consideration of component’s rack assignment and board mounting sequencing. An efficient PCB assembly method is developed by using neighboring positioned identical components information as well as quantity and size of the components. It is found that same type of components are located closely each other by checking real PCBs and interviewing with PCB designers in practice. Better performance of the developed procedure is obtained along with more number of total components and more number of neighboring positioned identical components cases. Simulation models are developed using Visual C++ for performance evaluation purposes of the suggested heuristic.

• Journal of Hydrogen and New Energy
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• v.27 no.4
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• pp.341-348
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• 2016

The experiments related on structure and water electrolysis performance of HALE UAV stack were conducted in this study. Anode catalyst $IrRuO_2$ was prepared by Adam's fusion methods as 2~3 nm nano sized particles, and the cathode catalyst was used as commercial product of Premetek. The MEA (membrane electrode assembly) was manufactured by decal methods, anode and anode catalytic layers were prepared by electro-spray. HALE stack was composed of 5 multi-cells as $0.2Nm^3/hr$ hydrogen production rate with hydrogen pressure as 10 bar. The water electrolysis performance was investigated at atmospheric pressure and temperature of $55^{\circ}C$. Best performance of HALE UAV stack was recorded as cell voltage efficiency as 86%.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.5 s.170
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• pp.80-86
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• 2005

Optical performance evaluation results and an interference fringe pattern analysis of alignment errors for an optical head of a near-field receding (NFR) system are presented. The focusing unit is an optical head of a NFR system and is composed of a solid immersion lens (SIL) and an objective lens (OL). Generally, the size of the focusing unit is smaller than that of the conventional optical recording head. Hence there are difficulties to assemble the small focusing unit precisely. We composed an evaluation system with an interferometer and evaluated some focusing unit samples aligned and assembled by manual and present the obtained results. Using the conventional optical tool, Code V, a tolerance analysis of the alignment error between the SIL and the objective lens and an interference pattern analysis for the assembly error are executed. Then, through an analysis of the simulation results, the conceptual auto-alignment methodology using a neural network approach is considered.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.5
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• pp.731-742
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• 2022

PIPO is the latest domestic lightweight block cipher announced in ICISC'20, which is characterized by being lightweight to facilitate implementation on IoT with limited resources. In this paper, PIPO 64/128-bit and 64/256-bit were implemented using web-based languages such as Javascript and WebAsembly. Two methods of performance evaluation were conducted by implementing bitsice and TLU, and the performance was compared by implementing Looped written using for statements and Unrolled written for statements. It performs performance evaluations in various web browsers such as Google Chrome, Mozilla Firefox, Opera, and Microsoft Edge, as well as OS-specific environments such as Windows, Linux, Mac, iOS, and Android. In addition, a performance comparison was performed with PIPO implemented in C language. This can be used as an indicator for applying PIPO block cipher on the web.

• New & Renewable Energy
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• v.2 no.2 s.6
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• pp.50-59
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• 2006

An experimental and numerical study is carried out to investigate the performance and the efficiency humidifying Membrane Electrolyte Assembly and having the double-layered catalyst in a fuel cell system which is taken into account the physical and thermal concept. Based on the principals of the problem, the equation of electronic charge conservation equation, gas-phase continuity equation, and mass balance equation are used for the numerical calculation. A unit cell for $200cm^2$ MEA is assembled and measured for finding better operational situation. After finding the optimal condition, 10 cell stacked PEMFC is fabricated. For the performance evaluation, V-I and power curves are examined in detail by changing the condition of humidity, temperature, pressure, thickness of catalyst and oxidant. It is found that the power is maximized around 500W at 80A.