• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.25 no.5
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• pp.321-328
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• 2016

Cranes are generally used to drop or lift equipment or materials. The present study focuses on equipment used for dropping and lifting the sonar system for undersea exploration. This study deals with a GA-based MATLAB$^{(R)}$ simulation for the design optimization of a new overboarding prototype with a two degree-of-freedom mechanism, including a parallelogram link, which is efficient in sonar system operation and maintenance. First, the strengths and weaknesses of the existing overboarding mechanisms are analyzed. The new mechanism to solve these problems is then suggested. For the proposed mechanism, the GA-based MATLAB$^{(R)}$ simulation technique is applied to the proposed mechanism to optimize the link lengths and the actuator lengths. By doing this, the mechanism cannot interfere in the hull's internal environment. Hence, the work range of motion (ROM) is satisfied, and good torque-angle properties are obtaind. The developed technology will be helpful in calculating the maximized output torque of the actuator for the application in practice using a similar type of the proposed mechanism.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.259-263
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• 2005

To compare cardiopulmonary effects and recovery between total intravenous anesthesia (TIVA) with propofol (PRO group, n=5) and volatile induction/maintenance anesthesia (VIMA) with isoflurane (ISO group, n=5), we investigated changes of heart rate, $SpO_2$, arterial pressure, rectal temperature and respiratory rate during 60 minute anesthesia and 40 minute recovery period in beagle dogs, and investigated recovery (extubation, head lift, sternal position and righting) after 60 minute anesthesia. Rectal temperature was significantly low in ISO group (p<0.05) from 10 to 100 minute. Heart rate was significantly low in ISO group (p<0.05) at 40, 50, 60 minute. Respiratory rate was significantly low in PRO group (p<0.05) at induction and 70 minute. $SpO_2$ tendency was similar. Systolic arterial pressure (SAP) was significantly low in ISO group (p<0.05) at induction and during anesthesia. Recovery was similar in two groups. We concluded that TIVA with propofol is useful in stabilizing rectal temperature and arterial pressure during anesthesia and provide fast and stable recovery.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.91-101
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• 2006

Lately, massive concrete structures are increasingly built. In such massive structures, the heat of hydration of mass concrete causes thermal cracks. To avoid thermal crack, methods widely acceptable for practical use are pre-cooling, pipe cooling and control of placing height. Thermal stress analysis is performed to find the way of controlling the thermal crack of pier footing mat in this paper. The footing mat model for the analysis is $12m{\times}14m$area and 3m height. The analysis results are compared with method of control of lift height and method of pipe cooling. The analysis results show that thermal crack can be removed by method of placing control and pipe cooling at footing mat placed on the ground.

• Journal of Appropriate Technology
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• v.5 no.1
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• pp.8-17
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• 2019

Solar pumps, for water lift systems, is becoming popular in rural areas for supplying drinking water in dry seasons when its need is elevated. The development in technology has also made solar pumps readily available and cheap which has increased its demands. So, for scattered settlements having a limited budget for operation and maintenance costs, solar pump is preferred over grid connected electrical pumping systems. This primary objective of the study was to design a solar photovoltaic pumping drinking water supply system for a small health post which is about 45 km east from Kathmandu, the capital city of Nepal. The study also compared and verified the final design with the system's existing design prepared by a development agency. The water source for this study was a confined aquifer 115m below the surface. The water demand was calculated to be 11m³ per day. A 1500 kPa submersible pump attached to a motor was selected and installed. Along with that twelve solar panels, reservoir, transmission main and distribution main was designed. The outcomes conclude solar photovoltaic pumping water supply systems to be cost-effective with an estimated cost of only USD 0.84 million per MLD. Solar pumps require low maintenance and operation costs and its repairs can quickly be done by the local people. The study also shows that solar technology produces no sound, needs no fuel making it environmentally friendly.

• International Journal of Aeronautical and Space Sciences
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• v.15 no.4
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• pp.374-382
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• 2014

This paper presents the computational aerodynamic analysis of a long-endurance UAV that was developed by the Korea Aerospace Research Institute (KARI), named EAV-2. EAV-2 is a technical demonstrator of aerodynamically efficient design, as well as a hybrid electric-propulsion system for future long-endurance UAVs. We evaluated the aerodynamic characteristics of six low-Reynolds number airfoils, using a panel method code, XFOIL, to select an optimal airfoil for the long-endurance mission of EAV-2. The computational results by a CFD code, FLUENT, suggested that the aerodynamic performance of EAV-2 would be notably improved after adopting SG6043 airfoil, and modifying the fuselage design. This reduced the total drag by 43%, compared to that of a previous KARI model, EAV-1, at the target lift of $C_L=1.0$. Also, we achieved a drag reduction of approximately 14% by means of the low-drag fuselage configuration.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.273-275
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• 2008

In Korea, over 97% of local energy demand is imported from other countries. And we have to lift the energy independence level up to 5% with replacement energy(renewable energy) such as solar, wind..etc. by 2011 according to the energy agreement made in Kyoto Protocol. So, we proposed some opinions such as the better improvement of solar thermal industry the people' view, cooperation among industry/university/research institutes, remote control/maintenance and government's legislature and supporting system etc.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.91-96
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• 2010

우리나라의 승강기 기술은 유럽, 미국, 캐나다의 기술표준을 도입함으로써 선진화를 꾀해오고 있으나, 초기의 틀에서 크게 벗어나지 못하고 있을 뿐만 아니라 품질서비스가 아직도 취약한 실정이다. 그 동안 서비스 품질의 정확한 구성요인을 파악하기 위한 연구가 다양하게 이루어져 왔지만, 대부분 서비스품질의 구성요인들 중 기능적 품질에만 국한된 연구가 주류를 이루어 왔으며, 서비스품질 구성요소를 통합한 승강기 유지보수산업에 대한 실증적인 연구는 거의 이루어지지 않은 실정이다. 이에 본 연구에서는 승강기 유지보수산업의 서비스 품질속성에 대한 고유속성과 척도 도출을 통해 경영성과 요인으로서의 고객만족도와 재무 비재무적 성과에 어떠한 영향을 미치는지에 대하여 실증분석하였다. 본 연구의 결과는 우리나라 중소벤처승강기 유지보수 산업의 서비스 품질 제고를 전략의 수립에 기초적인 자료로 활용될 수 있을 것이다.

• Proceedings of the Korean Society for Quality Management Conference
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• 2010.04a
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• pp.200-205
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• 2010

우리나라의 승강기 기술은 유럽, 미국, 캐나다의 기술표준을 도입함으로써 선진화를 꾀해오고 있으나, 초기의 틀에서 크게 벗어나지 못하고 있을 뿐만 아니라 품질서비스가 아직도 취약한 실정이다. 그 동안 서비스 품질의 정확한 구성요인을 파악하기 위한 연구가 다양하게 이루어져 왔지만, 대부분 서비스품질의 구성요인들 중 기능적 품질에만 국한된 연구가 주류를 이루어 왔으며, 서비스품질 구성요소를 통합한 승강기 유지보수산업에 대한 실증적인 연구는 거의 이루어지지 않은 실정이다. 이에 본 연구에서는 승강기 유지보수산업의 서비스 품질속성에 대한 고유속성과 척도 도출을 통해 경영성과 요인으로서의 고객만족도와 재무 비재무적 성과에 어떠한 영향을 미치는지에 대하여 실증분석하였다. 본 연구의 결과는 우리나라 중소벤처승강기 유지보수 산업의 서비스 품질 제고를 전략의 수립에 기초적인 자료로 활용될 수 있을 것이다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.73-78
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• 2003

Ultrasonic measurement is one of important technologies in the lift-time maintenance of nuclear poler plant. Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of ultrasonic inspection system is affected by its ability. The performance demonstration round robin was conducted to quantify the capability of ultrasonic inspection for in-service. The small number of teams who employed procedures that met or exceeded ASME Sec. XI Code requirements detected the piping of nuclear power plant with various cracks to evaluate the capability of detection and sizing. In this paper, the statistical reliability assessment of ultrasonic nondestructive inspection data using Monte Carlo simulation is presented. The results of the probability of detection (POD) analysis using Monte Carlo simulation are compared to these of logistic probability model. In these results, Monte Carlo simulation was found to be very useful to the reliability assessment f3r the small hit/miss data sets.

• Journal of the Korean Society for Railway
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• v.8 no.3
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• pp.260-266
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• 2005

The deterioration of a shunting locomotive was characterized for the lifetime assessment. The locomotive has been used for shunting works in steel making processes, and in this investigation, various types of technical evaluation methods for the locomotive parts were employed to assess the current deterioration status and to provide important clue for lifetime prediction. Unlike other rolling stocks in railway applications, the diesel shunting locomotive is composed of major components such as diesel engine, transmission, gear box, brake system, electronic devices, etc., which cover more than 70 percent of the total price of the locomotive. Therefore, in this paper, each part of major components in the diesel locomotive was analyzed in terms of the degree of deterioration. The lift-cycle-cost (LCC) analysis was performed based on the maintenance and repair history as compared with economical cost to provide the cost-effective prediction, i.e., to assess either repair for reuse or putting the locomotive out of service based on cost-effective calculation.