• 한국군사과학기술학회지
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• 제10권4호
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• pp.145-151
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• 2007

This paper considers new filter gains for the ${\alpha}\;-\;{\beta}$ tracker which is optimized particularly to minimize the tracking gate size. Optimizing the performance index which is composed of tracking errors due to target maneuver and measurement noise is not different from the existing method to obtain the ${\alpha}\;-\;{\beta}$ gains. However, holding the probability 0.997 that a target exists in the tracking gate and minimizing the gate size produce the new result not similar to the existing ${\alpha}\;-\;{\beta}$ gains.

• 한국해양공학회지
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• 제3권2호
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• pp.551-551
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• 1989

In general, a remotely operated vehicle(ROV) operates at deep sea. The control system of ROV is composed of two local loops; the first loop placed on the surface vessel monitors and manipulates the attitude of the ROV using joystick, and the second part on the ROV automatically controls thrusters and acquires positional data. This paper presents a position control simulation of a ROV using an adaptive controller and discusses the control effects of two different conditions. The design of an adaptive control system is obtained by the application of a self-tuning controller with the minimization of an appropriate cost function. The parameters of the control system are estimated by a recursive least square method(RLS). In the simulation, a Runge-Kutta method is used for the numerical integration and the generated outputs are obtained by adding measurement errors. Additionally, this paper discusses the mathematical modelling of a ROV and make a survey of control systems.

• 한국해양공학회지
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• 제3권2호
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• pp.51-58
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• 1989

In general, a remotely operated vehicle(ROV) operates at deep sea. The control system of ROV is composed of two local loops; the first loop placed on the surface vessel monitors and manipulates the attitude of the ROV using joystick, and the second part on the ROV automatically controls thrusters and acquires positional data. This paper presents a position control simulation of a ROV using an adaptive controller and discusses the control effects of two different conditions. The design of an adaptive control system is obtained by the application of a self-tuning controller with the minimization of an appropriate cost function. The parameters of the control system are estimated by a recursive least square method(RLS). In the simulation, a Runge-Kutta method is used for the numerical integration and the generated outputs are obtained by adding measurement errors. Additionally, this paper discusses the mathematical modelling of a ROV and make a survey of control systems.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.795-800
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• 2008

The sound transmission loss is a key index to evaluate the acoustic performance of a car-body structure at the high frequency range. From this paper, a new validation method for in-situ sound transmission loss is proposed. First, in-situ sound transmission loss is measured by using PU intensity probe on the condition of complete vehicle. Second, validation test, which is consisted of internal, external and total frequency response function test, is performed by using volume acceleration source and microphones. Then, these test results are compared to validate the accuracy of in-situ sound transmission loss. Finally, the test result of in-site method is compared with results of two reverberant room test method and SEA analytical method. The reliability of in-situ method is confirmed by these procedures.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.762-767
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• 2009

Some types of semi-Volatile organic compounds (SVOC) that are emitted from plastics used in building materials and household appliances have associated health risks, even at low concentrations. In this study, micro chamber method for measuring SVOC is introduced and SVOC such as di (2-ethylhexyl) phthalate and butylated hydroxyltoluene emitted a flooring material were measured using a micro chamber method. Airflow characteristics in a micro test chamber deeply depended on air exchange rate. From the evaluation using an index of air change efficiency, such as the air age and the coefficient of air change performance, a fixed air exchange rate of $1.5\;h^{-1}$ in the micro chamber is desirable.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.623-627
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• 2003

Aging and failure of motor insulation depend on the stresses imposed on it. The insulation life time depends on the severity of the stresses. The electrical aging by transient surge is very important to traction motor in EMU(electric multiple unit). This paper presents the insulation characteristics of stator coil by transient surge from inverter. There are several nondestructive tests available for checking the condition of motor insulation, the probable extent of aging, and the rate of which aging is taking place. So the insulation characteristics of stator coil were each analyzed by measurement of leakage current, dielectric loss($tan{\delta}$), capacitance, polarization index(PI) and partial discharge. The method of diagnosis is able to analyze the aging condition and predict the life of the traction motor in EMU.

• Current Optics and Photonics
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• 제4권6호
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• pp.551-557
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• 2020

A mirror-in-slab waveguide is fabricated on a slab waveguide by using the refractive-index contrast between two materials, with the reflection performance depending on the slab waveguide's design. In this research, a slab waveguide design consisting of silicon (Si) as the core and SiO2 as the substrate was designed and developed to determine the coupling, waveguide, and mirror losses. Based on experimental results, coupling loss is dominant and is affected by the design of the slab waveguide. Furthermore, the mirror loss is affected by the design of the mirror, such as the curvature radius and the size of the mirror. TE and TM polarizations of light are used in the measurements. The experimental results show that mirror losses due to reflection by mirrors are 0.011 dB/mirror and 0.007 dB/mirror for TE and TM polarizations respectively. A simulation was performed to confirm whether the size of mirror is sufficient to reflect the input light, and to check the quality of the surfaces of fabricated mirrors.

• 대한기계학회논문집B
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• 제38권11호
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• pp.873-879
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• 2014

CDA(Clean Dry Air) System 에서 공기 압축기는 핵심 설비이자 소비되는 전력의 대부분을 차지한다. 그리하여 압축기 성능(ECI)을 개선함으로써 CDA System 전체성능을 크게 향상 시킬 수 있다. 종래의 많은 연구를 통해 인입공기의 온/습도 조건이 압축기에 미치는 영향에 대해 잘 알려져 있으나, 본 연구에서는 인입공기의 조건에 따라 소비되는 실제 전력 및 토출유량의 상관관계를 조사하였다. 또한 증발 냉각장치를 설치하여 인입공기 조건의 다양한 변화를 통하여 압축기성능에 미치는 영향을 연구하였다. 얻어진 결과로부터 인입공기의 온/습도가 낮을수록 압축기성능이 개선되었고, 증발냉각장치를 설치하였을 때 압축기성능이 개선됨을 알았다.

• PNF and Movement
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• 제17권2호
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• pp.283-291
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• 2019

Purpose: The purpose of this study was to investigate the effects of trunk stability training on static balance and game records among archers. Methods: The subjects comprised 24 voluntary archers in middle and high school (aged 14-19 years). All the subjects received trunk stability training for an hour per day 3 days a week for 4 weeks. The Tetrax balance system was used to measure the stability index of the subjects' static balance. The subjects' game records were scored using a single FITA round system. All the subjects were measured before the intervention, 2 weeks into the intervention, and 4 weeks after the intervention, with a follow-up measurement 2 weeks later. Results: The results of this study showed that the stability index was significantly different across all the measuring positions after the intervention (p<0.05). Furthermore, the results of the measurements of the standing position with eyes open and closed were significantly different before the intervention compared to 4 weeks after the intervention (p<0.05). The archery position with the head turned to the left and eyes closed was also significantly different pre-intervention compared to 2 weeks after the start of the intervention (p<0.05). Additionally, the archery records were significantly different after the intervention (p<0.05), as well as before the intervention and 4 weeks after the intervention (p<0.05). Conclusion: Trunk stability training can improve static balance in archers. It may also be helpful in improving athletic performance and maintaining the life of the athlete. Accordingly, trunk stability training may prevent and resolve injuries through careful management when playing one-side sports.

• Journal of Animal Science and Technology
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• 제52권1호
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• pp.1-8
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• 2010

본 연구는 한우초음파생체단층촬영 자료를 이용하여 한우개량을 위한 기초자료로 활용코자 실시하였다. 당대검정우 1,125두에 대하여 초음파생체단층 촬영한 자료와 검정성적자료 및 12개월령에 거세한 후 30개월령까지 비육 후 출하하여 도체성적을 조사한 자료를 이용하였으며, 후대검정우는 921두에 대한 검정성적자료와 도체 성적자료를 이용하였다. 12개월령에 측정한 초음파생체단층 촬영 배최장근단면적과 등지 방두께의 유전력은 각각 0.57, 0.41로 추정되었으며, 24개월에서는 각각 0.57, 0.60으로 고도의 유전력을 보였다. 그러나, 초음파 측정 %지방함량 유전력 추정치에서는 12개월령과 24개월령에서 각각 0.14, 0.22로 저 중도의 유전력을 보였다. 12개월령에 초음파생체 단층 촬영한 배최장근단면적, 등지방두께, %지방함량과 도체형질의 배최장근단면적, 등지방두께, 근내지방도의 유전상관은 각각 0.616, 0.544, 0.501로 추정되었고, 24개월령에서는 각각 0.894, 0.937, 0.263으로 높은 유전상관을 보였다. 12개월령에 측정한 초음파 측정 %지방함량과 근내지방도에서 높은 유전상관으로 추정되었는데, 이는 24개월령에서는 환경적요인(사양기술 등)에 의해 영향을 많이 받은 것으로 사료되며, 선발에 활용할 경우 24개월령 측정치 보다는 12개월령 측정치를 이용하는 것이 더 바람직할 것으로 사료된다. 12개월령 체중과 도체형질을 이용하여 씨수소를 선발하는 선발지수와 이와 유전상관이 높은 초음파생체단층촬영 자료를 바탕으로 선발하는 선발지수간의 순위상관을 분석한 결과 12개월령에 초음파생체단층 촬영한 자료에서 후보씨수소 선발지수는 0.140, 보증씨수소 선발지수는 0.843으로 높은 순위상관을 보였다. 본 연구결과 실시간으로 배최장근단면적, 등지방두께, 근내지방도와 같은 도축하지 않아도 도체성적을 파악할 수 있는 초음파생체단층 촬영 기술의 장점을 이용하여 선발에 활용한다면 근내지방도는 24개월령에 측정하는 것보다 12개월령에 측정하는 것이 더 효율적이라고 사료되어지며, 향후 초음파생체단층기술에 관한 더 많은 연구를 통하여 종축선발에 활용한다면 씨수소의 조기선발이 가능할 것으로 사료된다.