• Journal of the Korean Society for Precision Engineering
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• v.15 no.6
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• pp.64-78
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• 1998

In this paper, on the basis of factory rationalization, the detection and evaluation system of weak assembly process was developed to analyze the processes for improvement of assembly productivity in the current assembly system. Using this detection and evaluation system of weak assembly process, the weak degrees of assembly process were quantitatively calculated. In this system, the improved design rules were constructed for assemblability and the redesign alternative was Presented for elimination of weak Process. After review of the redesign alternative, it was applied to the actual assembly system.

• Proceedings of the KWS Conference
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• 2005.06a
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• pp.34-36
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• 2005

Copper wire bonding is an alternative interconnection technology that serves as a viable and cost saving alternative to gold wire bonding. In this paper, ultrasonic wedge bonding with $25{\mu}m$ copper wire on Au/Ni/Cu metallization of a PCB substrate was performed at ambient temperature. The central composite design of experiment (DOE) approach was applied to optimize the copper wire wedge bonding process parameters. After that, pull test of the wedge bond was performed to study the bond strength and to find the optimum bonding parameters. SEM was used to observe the cross section of the wedge bond. The pull test results show good performance of the wedge bond. Additionally, DOE results gave the optimized parameter for both the first bond and the second bond. Cross section analysis shows a continuous interconnection between the copper wire and Au/Ni/Cu metallization. The diffusion of Cu into the Au layer was also observed.

• Journal of ILASS-Korea
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• v.2 no.3
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• pp.44-50
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• 1997

Bio-diesel oil is a great possibility to solve the pollution problem caused by the exhaust gas from diesel engine vehicles. Recently the use of bio-oils in disel engines has received considerable attention to the forseeable depletion of world oil supplies. So, Bio-diesel oil has been attracted with attentions as an alternative and clean energy source. The objective of this paper is to experimentally investigate the characteristic of performance using light oil, rice-bran oil, heated rice-bran oil, rice-bran oil treated with ultrasonic energy. We included rice-bran oil and applied ultrasonic energy to highly viscous bio-oils. These methods seems to have never been tried yet. The final data may be able to be applicated for the design of the diesel engine using an alternative fuel.

• International Journal of Air-Conditioning and Refrigeration
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• v.8 no.1
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• pp.40-49
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• 2000

The capillary tube performance for R-407C is experimentally investigated. The experimental setup is a real vapor-compression refrigerating system. Mass flow rate is measured for various diameter and length while inlet pressure and degree of subcooling are changed. These data are compared with the results of a numerical model. The mass flow rate of the numerical model is about 14% less than the measured mass flow rate. It is found that mass flow rate and length for R-407C are less than those for R-22 under the same condition. Based on this experimental study and the numerical model, a set of design charts for capillary tube of R-407C is proposed.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.181-184
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• 2009

This study aimed at framing alternative urban planning scenarios reflecting urban planning factors, performing urban climate simulation and evaluating eco-friend and low energy characteristics of each scenario on the viewpoint of urban temperature and energy savings on the target of the costal city including Haeundae District in Busan The results are as follows. 1)The fact that urban higher temperature is approximately 2.5 times higher in the building constructed area than whole urban area was represented severe higher temperature phenomenon in the built-up area. Ground greening, water scenario and soil scenario could be expected peek air temperature alleviating effect in order. Especially water scenario had significant effect(maximum $2.5^{\circ}C$) on lowering of air temperature.

• Journal of the Semiconductor & Display Technology
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• v.10 no.2
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• pp.19-23
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• 2011

Global warming is affecting all industries, and has been applied very quickly in the energy sector. Existing in all countries around the world by using fossil fuels to minimize environmental changes are developing a new alternative energy sources. Among the emerging alternative energy, using solar energy technology is applied across the industry, but the maintenance and repair to integrate solar cells and has been a problem occurs. To prolong the life of cells integrated on a solar cell is exposed when the non-eye, etc., when not integrated by the solar cells should not be exposed. In order to resolve these contradictions, a square solar flower of the biological mother was developed by using TRIZ technique(6SC).

• Journal of Korea Multimedia Society
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• v.11 no.12
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• pp.1688-1696
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• 2008

We propose a hierarchical service management method using Bloom filters for large MANETs. In this paper, a MANET is comprised of logical grid hierarchy, and each mobile node within the lowest service region multicasts the Attenuated Bloom Filter (ABF) for services itself to other nodes within the region. To advertise and discovery a service efficiently, the server node of the lowest server region sends the Summary Bloom Filter (SBF) for the ABFs to the server node of upper server region. Each upper server has the set of SBFs for lower vicinity service regions. The traffic load of the proposed method is evaluated by an analytical model, and is compared with that of two alternative advertisement solutions: complete advertisement and no advertisement. As a result, we identify that the traffic load of the proposed method is much lower than that of two alternative advertisement solutions.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.09a
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• pp.255-262
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• 2003

In present Korea Highway Bridge Standards the lap splice of longitudinal bars in a potential plastic hinge region is allowed so that large amount of transverse rebar specified in high seismicity regions Is required to prevent brittle bond failure If the brittle failure effects can be completely removed from the conventional designed piers, the amount of transverse rebar will be reduced drastically. In this study scaled models with solid and hollow rectangular sections were tested to investigate the seismic behavior of RC piers with 50％ of lap-spliced longitudinal bars in plastic hinge regions. In the tests the typical flexural failure conducting a ductile behavior were observed in both models. It is shown that the 50％ of lap-spliced bars can be considered as a good alternative of seismic detailing for longitudinal bars.

• Food Science and Industry
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• v.53 no.3
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• pp.256-263
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• 2020

Milk pasteurization is used to destroy harmful bacteria present in the raw milk for improvement of the keeping quality of dairy products. It is generally carried out in dairy industries as the heating process of raw milk in properly designed and operated equipment to a specific temperature for a specified a specified period. However, thermal processing may cause quality changes in milk as well as significant nutritional losses. Hence, many researchers have started work to design alternative strategies to produce safer foods with minimal thermal treatments for pasteurization. Therefore, the present paper shows the current status of commercial pasteurization system of dairy products in korean industry and the research efforts carried out by researchers on novel milk pasteurization system that could be an alternative to traditional thermal processes for maintaining the freshness of dairy products.

• Journal of Korea Multimedia Society
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• v.25 no.8
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• pp.1007-1021
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• 2022

Autonomous driving of unmanned aerial vehicles may have to pay expensive cost to create and switch new routes if unexpected obstacles exist or local map updates occured by the control system due to incorrect route information. Integrating digital twins into the path-following process requires more computing resources to quickly switch the wrong path to an alternative path, but it can quickly update the path during flight. In this study, we design a DEVS-based simulation environment which can modify optimized paths through short-term simulation of multi-virtual UAVs for applying digital twin concepts to path follow. Through simulation, we confirmed the possibility of increasing the mission stability of UAV.