• Journal of the Korean Society for Railway
• /
• v.20 no.3
• /
• pp.356-364
• /
• 2017

The process of inspecting electric railway vehicles is complicated and these vehicles accompany a risk of safety accidents. This developed system will be a great help in simplifying the shunting process and be very useful in terms of ensuring safety and providing user convenience. In this paper, the results of performance evaluation tests are studied on a movable catenary system for railway vehicles that secured mechanical durability, convenience, and operator safety by applying a specific rigid bar catenary of an existing mobile train line. We presented an analysis of the basic characteristics for site installation including sorting. In conclusion, this developed system was obtained in good results through durability test, durable mechanical load test and safety test in require specifications.

• Journal of the Korea Society of Computer and Information
• /
• v.28 no.10
• /
• pp.9-16
• /
• 2023

Technological advancement is being advanced in sports such as electronic protection of taekwondo competition and VAR of soccer. However, a person judges and guides the posture by looking at the posture, so sometimes a judgment dispute occurs at the site of the competition in Taekwondo Poomsae. This study proposes an artificial intelligence model that can more accurately judge and evaluate Taekwondo movements using artificial intelligence. In this study, after pre-processing the photographed and collected data, it is separated into train, test, and validation sets. The separated data is trained by applying each model and conditions, and then compared to present the best-performing model. The models under each condition compared the values of loss, accuracy, learning time, and top-n error, and as a result, the performance of the model trained under the conditions using ResNet50 and Adam was found to be the best. It is expected that the model presented in this study can be utilized in various fields such as education sites and competitions.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.19 no.2
• /
• pp.702-709
• /
• 2018

A quick-hardened concrete track was developed to improve the aged ballasted track to a concrete track, and applied to earthworks and tunnels of main and urban railways. Rebars for reinforcement are not generally applied to prestressed concrete sleepers. On the other hand, many cracked sleepers have been observed in railroad sites. A wide sleeper, which is one of the main components of quick-hardened concrete track, should be structurally safe and crack-resistant in a ballasted and concrete track to avoid this problem. In particular, a wide sleeper manufactured by a post-tension method must have reinforcing bars applied to the rail-seat section. In this paper, static tests, dynamic tests, and fatigue tests were carried out to compare the flexural strength and crack resistance performance of a wide sleeper with and without reinforcing bars for a quick-hardened concrete track. As a result of the test, if some reinforcing bars are applied appropriately to the rail-seat section of a wide sleeper, it will be possible to prevent the occurrence of cracks, delay the expansion of the crack width, and the flexural fracture.

• Fire Science and Engineering
• /
• v.30 no.6
• /
• pp.84-91
• /
• 2016

In case of fire, vertically and intensively loaded rack warehouses are faced with a severe status due to the rapid increase in fires. In this regard, there have been trials to prevent fires from spreading by applying fire extinguishing systems, such as ESFR and In-Rack Sprinklers, vertical and horizontal barriers, etc.; however, it is difficult to calculate and design proper fire extinguishing systems caused by various composition conditions, such as the size and loading density of the rack, types of loading commodities, etc. Therefore, in this study, a standard rack was manufactured, incorporating a rack warehouse in Korea by site investigations, surveys, etc. In addition, a full scale fire test was executed to check the fire characteristics depending on the conditions of the ignition points. As a result, the extracted fire spread speed is expected to be utilized as a reference for performance comparisons of the fire extinguishing systems to be developed and applied in the future.

• Proceedings of the KWS Conference
• /
• 2009.11a
• /
• pp.28-28
• /
• 2009

최근 전세계적으로 유가 상승 및 배기가스 배출 저감과 관련된 각종 환경규제에 대응하기 위하여 선진 자동차회사들은 $CO_2$ 배출 저감 기술과 기존 내연기관 차량의 연비향상을 위해 엔진성능 개선, 구동시스템의 최적화, 차량 경량화, 공기저항 감소 등에 초점을 맞춰 차량의 연비향상과 배기가스 규제에 대응하고 있다. 특히, 자동차 중량의 30%를 차지하는 차체의 경량화는 엔진효율을 높여 자동차의 성능향상을 극대화시키고, 그로 인해 연비향상을 도모할 수 있으므로 환경오염 방지와 연료절감에 가장 적합하고 효과적인 방법이다. 이에 기존의 강재에 비해 비중이 낮으면서 유사한 강도와 내식성이 뛰어난 알루미늄 합금의 차체 적용에 대한 연구가 진행되고 있다. 본 연구에서는 자동차 Door에 알루미늄 합금(Al 5052)의 적용 가능성을 판단하기 위해 반응표면분석법(Response surface methodology)을 이용하여 저입열 Pulse MIG 용접 공정변수를 최적화하였다. 첫째, 저입열 Pulse MIG 용접에서 용접 공정 변수(용접전압, 용접속도, Gap)의 변화가 비드 형상에 미치는 영향에 대해 평가하였다. 요인분석법을 이용하여 용접 공정 변수와 비드 형상 변수와의 주효과와 교호작용효과를 분석하였고, 이를 통해 비드 형상 변수에 영향을 크게 미치는 용접 공정변수를 선별하여 다중회귀분석을 통해 용접 공정 변수 변화에 따른 비드형상 예측 회귀모델을 제안하였다. 둘째, 자동차 Door 생산 현장에서 박판 알루미늄 합금 겹치기 용접 이음부의 0~1 mm 갭 발생에 대해 강건한 용접조건을 제시하기 위해 반응표면법(Response surface methodology)을 이용하여 저입열 Pulse MIG 용접 공정 변수를 최적화하였고, 그 적용 가능성을 확인하였다.

• Composites Research
• /
• v.37 no.4
• /
• pp.265-274
• /
• 2024

This study reviews previous research on various coating materials and methods designed to improve the adhesion and durability of steel pipes exposed to real-world marine environments, with the goal of identifying optimal solutions. The results concerning the adhesion and corrosion resistance of the pipes were categorized and analyzed based on exposure tests in extreme marine conditions to evaluate their stability. Furthermore, a detailed microstructural analysis of the coatings applied to the pipes was performed to assess surface damage, including peeling and delamination. The findings confirmed that coatings effectively prevent corrosion and provide sufficient adhesion and durability. Based on these results, we have proposed suitable coating materials, types, and application methods for steel pipes used in marine environments and offered recommendations for future exposure tests.

• The KIPS Transactions:PartA
• /
• v.13A no.4 s.101
• /
• pp.335-342
• /
• 2006

As PRC linear interpolation algorithm is applied after analysed and verified in this paper, the unknown location of a user can be identified by using PRC information of multi-DGPS reference station. The PRC information of each GPS satellite is not varying rapidly, which makes it possible to assume that PRC information of each GPS satellite varies linearly. So, the PRC regeneration algorithm with linear interpolation can be applied to improve the accuracy of finding a user's location by using the various PRC information obtained from multi-DGPS reference station. The desirable PRC is made by the linear combination with the known position of multi-DGPS reference station and PRC values of a satellite using signals from multi-DGPS reference station. The RTK-GPS result was used as the reference. To test the performance of the linearly interpolated PRC regeneration algorithm, multi-channel DGPS beacon receiver was built to get a user's position more exactly by using PRC data of maritime DGPS reference station in RTCM format. At the end of this paper, the result of the quantitative analysis of the developed navigation algorithm performance is presented.

• Korean Journal of Remote Sensing
• /
• v.39 no.5_1
• /
• pp.537-549
• /
• 2023

The distribution characteristics of tidal flat sediment components are used as an essential data for coastal environment analysis and environmental impact assessment. Therefore, a reliable classification map of surface sedimentary facies is essential. This study evaluated the applicability of regression kriging to generate a classification map of the sedimentary facies of tidal flats. For this aim, various factors such as the number of field survey data and remote sensing-based auxiliary data, the effect of regression models on regression kriging, and the comparison with other prediction methods (univariate kriging and regression analysis) on surface sedimentary facies classification were investigated. To evaluate the applicability of regression kriging, a case study using unmanned aerial vehicle (UAV) data was conducted on the Hwang-do tidal flat located at Anmyeon-do, Taean-gun, Korea. As a result of the case study, it was most important to secure an appropriate amount of field survey data and to use topographic elevation and channel density as auxiliary data to produce a reliable tidal flat surface sediment facies classification map. In addition, regression kriging, which can consider detailed characteristics of the sediment distributions using ultra-high resolution UAV data, had the best prediction performance compared to other prediction methods. It is expected that this result can be used as a guideline to produce the tidal flat surface sedimentary facies classification map.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.16 no.5
• /
• pp.97-103
• /
• 2002

The assessment of the condition of a transformer winding which is suspected of having suffered short circuit damage can be difficult. Conventional test such as winding resistance, magnetic current or insulation resistance will only detect damage if a permanent electrical fault exists. Visual inspection of windings necessitates the removal of oil and in many cases only a very small proportion of the winding can be seen. We describe the characteristic of LVI test system and methods to detect the deformation of windings in the power transformers. As the front rise time of recurrent-surge generator pulse less than 1000 ㎱ and the peak value of pulse is about 500 V, we have the good results of detecting winding deformation in the LVI test of transformers.

• Journal of Korean Society of Transportation
• /
• v.26 no.2
• /
• pp.167-176
• /
• 2008

Although a rate of car accident death is on the decrease, internal rate of median encroachment accident is still high. In order to reduce the median encroachment accident, government use median barriers but there are no exact criteria of them. Particularly, current impulse measurement method has adopted the uniformly operating speed and encroachment angle. At reality, however, there are various conditions depends on driver's characters. In that reason, this study calculates reasonable impulse quantity through encroachment angle and operating speed. It will be necessary to prevent overuse treasury and car accidents.