• Title/Summary/Keyword: Engineering M&S

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Validation of Exercise Effect in Rehabilitation during Knee Extension of the Lower Limbs using Pneumatic Exercise System (공압운동기기의 하지 슬관절 운동 시 재활운동 효과의 유효성에 관한 연구)

  • Lee, H.J.;Kang, S.R.;Kim, K.;Jeong, G.Y.;Yu, M.;Kim, J.J.;Kwon, T.K.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.5 no.1
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    • pp.1-10
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    • 2011
  • Our study is to verify validation of exercise effect that developing exercise and rehabilitation instrument using pneumatic actuators available rehabilitation and healthcare, while at the same time safer and more convenient for the user to select the desired exercise. Shares subject to the usual exercise is conducted in less than a week in the knee extension and flexion at the undergraduate level there is no more than 10 of the 20 patients were female. Subject performed knee exercise 3 set a day with 12times a set using fluid type exercise instrument and pneumatic exercise instrument that build in this study. Experiment has progressed in 4-weeks with 3-days a week. Our exercise load consist of two type. One is active exercise load with developed instrument in our study and the other one is passive exercise load with fluid instrument. Exercise program based on real-time muscle activation patterns and muscle activity before and after exercise by comparing the effects of exercise for rehabilitation has been verified. The results showed that muscular activity is higher in active exercise load than passive load, and improvement of muscle strength more increased too. Equipment more user-centered exercise more effectively exercise may enhance muscle strength was found. This study can adapt rehabilitation program and exercise for patient and weaker. Also our system can provide easily and convenient prescription of rehabilitation for expert related rehabilitation.

Development of Management Systems based on IDEF3 Modeling to Improve Owner's Competency of Implementing Green building Certification (친환경건축물인증 발주자업무 수행역량 제고를 위한 IDEF3 모델기반 관리체계 구축)

  • Park, Kyung-Rog;Yi, June-Seong
    • Korean Journal of Construction Engineering and Management
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    • v.14 no.1
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    • pp.52-62
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    • 2013
  • Owners' efforts to acquire Green building certification, which started in 2002, have been rapidly increasing since 2006. The causes of the increased owners' interests are due to various incentives, legal obligation, and purpose of advertising. As project owners generally are deficient in capabilities and knowledge on how to deal with administrative works on certification, they tend to fulfill the minimum requirements for certification. However, effective administration process need capabilities of identifying individual making decision point and review information. The implementation of green building certification system is expected to provide comfort to both occupants and potential users. Furthermore it contributes to reducing energy costs throughout the phase of O&M. In addition, technology innovation in green industry can be obtained. Therefore, this study is intended to support owners in order that they can clarify certification tasks and make a rational decision-making in time. For this purpose, first of all, the major decision points were selected as the gateways of green building certification process. And then management system based on IDEF3 modeling was developed for supporting owners' decision-making performance. This management system will improve owners' overall capacity in handling all the tasks regarding the certification of Green building.

An Analysis on the Vibration Characteristic of a Automobile at the Sudden Change of an Accelerator under Traveling (주행중 가속페달의 급조작시 승용차의 진동 특성 해석)

  • 홍동표;정태진;김상수
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1994.04a
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    • pp.76-81
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    • 1994
  • 승용차에 있어 엔진의 공회전시나 주행중에 발생하는 여러 형태의 진동 및 소음의 저감은 승차감 및 차량의 안정성에 있어 중요한 과제가 되고 있다. 이러한 소음, 진동은 주로 엔진에서 발생하는 토크의 비주기적인 변동성분이 클러치(clutch), 변속기(transmission), 구동축을 거쳐 바퀴로 전달되는 과정에서 발생한다. 셔플(shuffle)은 주행중 가속페달(accelerator)을 급조작(tip-in, tip-out)하였을 때 차량이 전후로 과도적으로 울렁거리는 종진동 현상을 말하며, 이것은 가속페달의 급조작으로 인해 엔진토크가 큰 변동을 일으키고, 동력전달계를 통해 타이어에 전달된 이 토오크는 타이어축에서 구동측으로 역토오크를 발생시키기 때문에 발생한다. 여기서 팁-인(tip-in)이란 승용차를 저속으로 운전하다가 갑자기 가속페달을 밟는 경우를 말하며, 팁-아웃(tip-out)은 반대로 고속상태에서 갑자기 가속페달을 떼는 경우를 말한다. 실험과 시뮬레이션을 사용한 자동차 동력전달계의 비틀림 진동에 대한 연구는 이미 여러 연구자들에 의해 보고되었다. H.Arai은 2자유도 비선형 모델을 사용하여 클러치 접속시 발생하는 외란과 계의 안정성을 고려하여 시뮬레이션을 수행하였고, M.Kataoka는 기어의 공차(clearance)를 고려한 변속기의 강제 비틀림 진동을 실험과 시뮬레이션을 통하여 해석하였다. 그리고, Wu Hui-Le는 자동차 동력전달계의 비틀림 진동 현상을 실험과 이론적인 계산을 통해 연구하였고, R.J.Comparin는 치타음의 발생구조와 특성을 고찰하고 비서형 비틀림 공진 저감에 의한 치타음 저감 기법에 대하여 연구하였다. 또한 G.J.Fudala는 다자유도 모델을 이용하여 클러치의 비틀림 특서엥 따라 주파수분석을 수행하여 치타음 저감 방법을 연구하였고, T.Sakai는 5자유도 모델을 이용하여 엔진 공회전시 발생하는 치타음에 대해 이론과 실험을 통해 해석하고, 엔진 회전수 변동, 클러치 특성, 변속기의 드래그(drag) 토크의 영향과 치타음 저감을 위한 개선된 클러치 특성을 제시하였다. 이 외에도 Thomas C.T.와 E.P.Petkus는 특정 차량에 대한 동력전달계의 비틀림 진동 현상에 대해 연구하였다. 이러한 연구들로 볼 때, 자동차 동력전달계에서 발생하는 진동은 이론과 실험을 통해 그 해석이 가능하며 설계에 매우 유용하게 이용되고 있음을 알 수 있다. 따라서, 본 연구는 4 실린더 4 싸이클 1.5 L 엔진을 장착한 경승용차의 실차 주행실험을 통해 가속 페달의 급조작에 따른 차체의 종진동 현상을 측정하고, 엔진-변속기-타이어-차체의 반환정계 4자유도 진동모델로 시뮬레이션을 수행하여 실차 주행실험의 결과치와 비교, 분석한 후 클러치 비틀림 특성을 비롯한 자동차 동력전달계의 각 설계인자들이 차체의 종진동에 어떠한 영향을 미치는가를 해석하고자 한다.

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Study on the Improvement Impaired Driving Environment of the IT Convergence-based Road Safety at Road Construction Sites with a Robot Protector (IT 융합기반 도로안전지킴이로봇을 통한 도로 건설 현장에서의 장애인운전환경 개선 연구)

  • Lee, S.Y.;Kim, D.O.;Rhee, K.M.
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.9 no.1
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    • pp.17-21
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    • 2015
  • There have been sustained developments of advanced technologies using traffic safety facilities recently and techniques for identifying failure modes and devices which could result in fatal outcomes. The purpose of this research is aimed at improving the driving conditions in advance through analyzing the IT convergence, driving education, researches for vehicles, field of construction and robotics. The researchers evaluate on usability tests of the driving with 26 candidates through focusing on safety, convenience, efficiency, effectiveness. Using specialized LED panel to enhance driving performances of disabled people are for cautious road conditions like foggy weather or heavy rain. As a result, there were improvements in the driving conditions, and candidates reported this system was helpful. It allows them for maintaining proper driving all times and was especially informative for people with low vision or visually impaired. This system plays a pivotal role as a prevention mechanism not only for regular drivers but also for further delict of traffic violations or accident offenders who already have former record on tort.

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Dynamic Characteristics of Actuator for High Density Optical Recording Pick-up (고밀도 기록용 광픽업의 ACTUATOR 동특성)

  • 임경화;이용훈;김석중;이재원
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1995.04a
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    • pp.258-263
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    • 1995
  • 미래 정보와 시대에서 중추적인 역할을 할 광관련 멀티미디어 장비들은 최근 관련 산업계에서 주목을 받기 시작하고 있고 특히 기존 VTR(Video Tape Recorder) 시장을 대체할 차세대 DVDR(Digital Video Disk Recorder)는 기술전쟁이라고 할 정도로 선진 기업의 연구가 치열해지고 있다. DVDR 시스템에서는 필요한 정보들을 레이저빔을 이용한 광학신호로 바꾸어 광디스크에 기록, 재생하는 광픽업이 절대적으로 필요하게 된다. 그런데 광픽업의 위치추종기구인 Actuator는 정확한 위치추종(.+-.1.$\mu$m 오차이내)을 할 수 있는 성능이 요구되며 서보의 특성상 20KHz 이하에서 불필요한 모우드가 가진되지 않는 정밀부품이어야 하므로 Actuator 각 부품의 동적인 특성을 명확히 규명할 필요가 있다. 따라서 본 연구에서는 우선 Actuator 각 부품과 가동부 전체의 중량 및 진동해석을 통해 동특성을 조사하였다. 그리고 Actuator의 중요한 기본성능중 하나인 구동감도 확보여부를 검토할 필요가 있기 때문에 유한요소법 프로그램인 ANSYS를 이용하여 자기회로 부분에 대한 해석을 구하였다. 또한 가동부와 자기회로 등 하위부품을 조립하는 과정에서 발생하는 조립오차로 인해 불필요한 공진과 회전형상이 야기될 수 있으므로 동특성 및 문제점 파악을 위한 민감도 분석이 필요하다. 따라서 본 연구에서는 가동부의 관성 모멘트 값과 강체에 대한 일반식을 이용한 자체 프로그램을 작성하여 조립공차를 구하였다. 이와같은 과정을 통해 구해진 설계값을 바탕으로 실제 제작된 Actuator에 대해서는 비접촉식 측정방법을 통해 동특성값을 측정하였고 이를 해석값과 상호 비교하였다.동강성행렬법(dynamic stiffness matrix method)을 이용하여 해석하고자 한다. 수준임이 입증되었다. 본 연구의 결과를 토대로우리나라 젊고 건강한 남성에게 적합한 무게상수는 작업자군에 대하여 25.05kg, 학생군에 대하여 20.24kg 으로 나타나 이는 미국 NIOSH 안전기준과 대체로 일치함을 발견하였다.ive structures utilized in Client/server architecture for distribution and cooperative processing of application between server and client this study presents two different data management methods under the Client/server environment; one is "Remote Data Management Method" which uses file server or database server and. the other is "Distributed Data Management Method" using distributed database management system. The result of this study leads to the conclusion that in the client/server environment although distributed application is assumed, the data could become centralized (in the case of file server or database server) or decentralized (in the case of distributed

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Development of Unfolding Radial Velocity Algorithm for Dual PRF Mode of Yong-In Testbed(YIT) Radar (용인테스트베드레이다를 이용한 Dual PRF 모드의 시선속도 접힘 풀기 알고리즘 개발)

  • Kim, Hye-Ri;Suk, Mi-Kyung;Nam, Kyung-Yeub;Ko, Jeong-Seok
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.27 no.6
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    • pp.521-530
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    • 2016
  • Weather radar is observation equipment that transmits electromagnetic waves and receives backscattered signals from the targets. The weather radar systems of the Korea Meteorological Administration have a doppler mode that can extract the target's radial velocity. However, the radial velocity over the maximum unambiguous velocity(${\nu}_m$) for which is in a trade-off relationship with the maximum unambiguous range is folded. Therefore, a dual PRF mode of which transmits and receives signals using two different PRFs(high and low) must be used to extend the vm while maintaining the maximum unambiguous range. Using a dual PRF mode, vm can be extended to the amount of lowest common denominator of two observed vm from high and low PRF. For this extension, we have developed a velocity unfolding algorithm of which uses several criteria for classification considering observed velocity differences between high and low PRF and their error boundary. Then, correction factors are calculated for each class and are applied to unfold radial velocity. The developed algorithm was applied to the Yong-In Testbed(YIT) radar and the generated better performance of radial velocity extraction than those of the previous system.

Improving Reliabilities of Dam Displacement based on Monitoring Given Points by Total Station (기준점 측량을 활용한 광파기 기반 댐 제체 변위 계측 신뢰도 향상)

  • Kang, Gi-Chun;Kim, Bong-Jae;Hong, Seok-Woo;Yim, Yeon-Chool;Kim, Ji-Seong
    • Journal of the Korean Geosynthetics Society
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    • v.16 no.1
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    • pp.1-8
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    • 2017
  • Displacement of dams by various instrumentations has been monitored for its safety management and analyzing the behavior after a dam collapse accident. However, unknown displacement of dam has frequently been occurred and it's difficult to analyze behavior of dams more accurately. In this study, improvement of reliabilities for displacement of dams measured by a total station was suggested by calibrating the monitoring system. The position of total station was initially measured through 2-3 given points and the coordinate of the total station was considered as an absolute value. Also, base horizontal and vertical angles had not been considered even if they are important factors when displacement was estimated. In this study, location of the total station and variations of base horizontal and vertical angles were investigated during measuring displacements of targeting points. From the results of this study, they are important factors which are affecting measurements of dam displacements. Before the calibrating, the displacement at 50 m from total station was ${\pm}20mm$. After the calibrating, the displacement was decreased by ${\pm}5mm$.

The study of Efficient Treatment Conditions on the Composting of Foodwaste (음식쓰레기의 퇴비화공정의 적정운전조건 검토)

  • Kang, Chang-Min;Kim, Byoung-Man;Jeoung, Il-hyun
    • Journal of the Korea Organic Resources Recycling Association
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    • v.11 no.2
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    • pp.117-124
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    • 2003
  • The purpose of this study was to investigate the optical conditions to satisfied the salt concentration of 1% below of compost produced by using the material of foodwaste and sawdust. We changed the mixing ratios of foodwaste : sawdust from 7:3 to 3:7 and the ratios of foodwaste : rice hull from 6.5:3.5 to 4:6. We analyzed C/N, pH, temperature, water content, volatile solid, salt, heavy metals to check the degree of composting. The running conditions of composting were $80{\sim}133{\ell}/min{\cdot}m^{3}$ of air flow rate, 1:4 of time interval(on:off) and 7days of turning interval. Running times were 28days. The optical mixing ratio of foodwaste : sawdust was 6:4 when we compared many factors. Especially when the mixing ratios of foodwaste : sawdust or foodwaste : sawdust were 7:3 or 6:4, the composting was not accomplished by the reason of low C/N. The concentrations of heavy metal were sufficiently low to satisfied the satandard of organic compost. The salt concentration was 0.43%-0.46% that was the half of initial concentration. The rice hull was the good in pore rate and 통기성, and so it can used alternative material.

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Anti-proliferative Effects of Celastrol, A Quinine Methide Triterpene Extracted from the Perennial Vine Tripterygium wilfordii, on Obesity-related Cancers (미역줄나무 뿌리 추출물인 셀라스트롤의 비만관련 암증식 억제효과)

  • Park, Sunmi;Moon, Hyun-Seuk
    • Journal of Food Hygiene and Safety
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    • v.31 no.1
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    • pp.59-66
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    • 2016
  • It has been generally accepted that obesity and overweight are associated with metabolic diseases and cancer incidence. In fact, obesity increased risks of cancers i.e. breast, liver, pancreatic and prostate. Celastrol is a pentacyclic triterpenoid isolated from Thunder god vine, was used as a Chinese traditional medicine for treatment of inflammatory disorders such as arthritis, lupus erythematosus and Alzheimer's disease. Also, celastrol has various biological properties of chemo-preventive, neuro-protective, and anti-oxidant effects. Recent studies demonstrated that celastrol has anti-proliferation effects in different type of obesity-related cancers and suppresses tumor progression and metastasis. Anticancer effects of celastrol include regulation of $NF-{\kappa}B$, heat shock protein, JNK, VEGF, CXCR4, Akt/mTOR, MMP-9 and so on. For these reasons, celastrol has shown to be a promising anti-tumor agent. In this review, we will address the anticancer activities and multiple mechanisms of celastrol in obesity-related cancers.

Numerical Study of Evaporation and Ignition of in-line Array Liquid Droplets (액적 배열의 증발과 착화에 관한 수치해석적 연구)

  • 김충익;송기훈
    • Fire Science and Engineering
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    • v.13 no.1
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    • pp.37-47
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    • 1999
  • The spreading fire of very small floating particles after they are ignited is fast and t therefore dangerous. The research on this area has been limited to experiments and global simulations which treat them as dusts or gaseous fuel with certain concentration well m mixed with air. This research attempted micro-scale analysis of ignition of those particles modeling them as liquid droplets. For the beginning, the in-line array of fuel droplets is modeled by two-dimensional, unsteady conservation equations for mass, momentum, energy and species transport in the gas phase and an unsteady energy equation in the liquid phase. They are solved numerically in a generalized non-orthogonal coordinate. The single step chemical reaction with reaction rate controlled by Arrhenius’ law is assumed to a assess chemical reaction numerically. The calculated results show the variation of temperature and the concentration profile with time during evaporation and ignition process. Surrounding oxygen starts to mix with evaporating fuel vapor from the droplet. When the ignition condition is met, the exothermic reactions of the premixed gas initiate a and burn intensely. The maximum temperature position gradually approaches the droplet surface and maximum temperature increases rapidly following the ignition. The fuel and oxygen concentration distributions have minimum points near the peak temperature position. Therefore the moment of ignition seems to have a premixed-flame aspect. After this very short transient period minimum points are observed in the oxygen and fuel d distributions and the diffusion flame is established. The distance between droplets is an important parameter. Starting from far-away apart, when the distance between droplets decreases, the ignition-delay time decreases meaning faster ignition. When they are close and after the ignition, the maximum temperature moves away from the center line of the in-line array. It means that the oxygen at the center line is consumed rapidly and further supply is blocked by the flame. The study helped the understanding of the ignition of d droplet array and opened the possibility of further research.

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