• Journal of Institute of Control, Robotics and Systems
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• v.7 no.2
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• pp.168-172
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• 2001

The accuracy problem of robot manipulators has long been one of the principal concerns in robot design and control. A practical and economical way of enhancing the manipulator accuracy, without affecting its hardware, is kinematic calibration. In this paper an effective and practical method is presented for kinematic calibration of Stewart platforms. In our method differential errors in kinematical parameters are linearly related to differential errors in the platform pose, expressed through the forward kinematics. The algorithm is tested using simulated measurement in which measurement noise is included.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.844-846
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• 1999

Chronic irritation to arterial wall by foreign material may give rise to delayed vascular injury. A 50 years old male patient with kyphoscoliosis had undergone fixation of orthopedic Cotrel-Dubousset(CD) rods and screws. Fourteen months after that surgery, a false aneurysm of the descending thoracic aorta associated with pulsating hematoma in the muscular chest wall developed. The false aneurysm was managed by resecting the diseased aortic segment and replacing the vascular graft.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.3-3
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• 2010

이번 성원에드워드 학술상 수상자 선정은, 진공기술의 중요성에 공감하고 진공기술 발전을 위한 노력을 독려하자는 진공학회 회원들의 의견을 모아주신 결과로 생각한다. 본 발표에서는 그동안 한국표준과학연구원에서 수행해 온 진공 기술 연구 및 산학연 협력 네트워크 활동을 소개하고자 한다. 진공기술은 진공 환경을 발생시키고 측정 제어하며, 만들어진 진공 환경 안에서 원하는 작업을 할 수 있도록 하는 기술을 말한다. 우리나라의 주력산업인 반도체 및 디스플레이의 경우 그 생산 설비의 1/3이상이 진공 장비이며 진공 공정을 통해 만들어진다. 때문에 우리나라에서는 주력 산업분야나 그 전후방 산업의 경쟁력 강화 측면에서 진공기술 개발 중요성이 아주 크다. 한국표준과학연구원은 국가 대표 측정 기관으로 국가 측정 표준을 확립하고 측정관련 과학기술을 연구개발하며 그 성과를 보급하여 경제발전과 과학기술발전, 그리고 삶의 질 향상에 기여하는 것을 임무로 하고 있다. 우리나라에서 진공 측정 표준에 대한 연구가 본격적으로 시작된 것은 1984년으로 불용 장비로 불하받은 펌프와 챔버, 그리고 차관으로 도입된 Capacitance Diaphragm Gauge 몇 개만으로 시작되었다. 지금은 발전을 거듭하여 초음파 간섭 수은주 압력계를 비롯하여 정적 팽창시스템, 동적 팽창 시스템 등 진공도 범위별 국가 표준기와 리크 표준기를 자체 개발 하여 국가 측정 표준을 확립하고 있다. 우리나라의 진공 표준 및 측정 능력은 국제기구인BIPM에서 실시하는 국가 측정능력 비교시험을 통해 세계 최고 수준으로 인정 받은 바 있으며 교정검사 등을 통해 산학연에 보급되고 있다. 진공 측정 및 표준기술을 토대로, 1999년부터 과학기술부와 산업자원부의 지원을 받아 산학연이 필요로 하는 펌프 계측기 부품 소재 및 공정 특성을 평가하기 위한 장치와 절차를 개발하였다. 이를 이용해 보급되는 기술 data는 진공부품 및 장비 국산화, 국산제품 신뢰성 제고, 검증부품 사용을 통한 장비 품질 향상, 독자적 장비 기술 확보, 생산품 품질관리 등에 쓰이고 있다. 한국 표준연구원 진공센터의 교정 및 시험 능력은 ISO 9001 인증 획득과 국제 전문가의 review를 거쳐, 국제기구 측정능력표에 등재되어 있어 국제적 신뢰도도 확보하고 있다. 정기적인 진공기술 교류회를 개최하고 진공기술 홈페이지를 운영 하는 등 산학연 정보 교류 및 협력 네트워킹 활성화를 위해 노력한 바 있으며 이 분야의 연구 성과는 '국가 우수 연구성과 100선'에 선정된 바 있고, 산업자원부 지정 '산학연 연계 우수사례' 첫 번째로 선정되기도 하였다. 2008년부터는 진공기술 교류회 등을 통한 네트워킹 활동으로 도출된 기술 수요에 따라 대기업과 중소기업 학교 연구소들과 함께 진공공정 실시간 측정 진단 기술과 센서 개발 연구, 그리고 이들 개발품의 신뢰성 검증 및 평가 기술 개발을 위해 노력하고 있다.

• Journal of the Korea Convergence Society
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• v.9 no.2
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• pp.303-311
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• 2018

Squat exercise is one of the free weight exercises that are recognized as important from a bio-mechanical point of view. It is an important exercise to train lower extremity muscles in daily activities or sports activities and to strengthen trunk and lower body strength. It is effective and accurate to use a variety of assistive devices to calibrate athletic posture with squat exercise supported interactive device. The issues of the structural analysis for design a foot plate for squat exercise is to model the behavior by simplifying the dynamic behavior. In this paper, the authors proposed a exercise system design method for the vertical load distribution and bio-mechanical signal process used for the squat exercise mechanism analysis, and based on these results, designed device can make the more safe and reliable free weight exercise. It is applied to system design through design method with kinematic dynamic, VR device and estimation model of exercise.

• The korean journal of orthodontics
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• v.40 no.3
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• pp.184-194
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• 2010

Objective: The purpose of this study was to investigate the effect of tribochemical silica coating on the shear bond strength (SBS) of rebonded ceramic brackets using nano-filled flowable composite resin. Methods: A total of 60 premolars were prepared and divided into 4 equal groups as follows: Tribochemical silica coating (TC) + Transbond XT (XT), TC + Transbond supreme LV (LV), Sandblast treatment (SA) + XT, SA + LV. Treated ceramic brackets were rebonded on the premolars using each adhesive. All samples were tested in shear mode on a universal testing machine. Results: SBS of silica coated groups were high enough for clinical usage (TCLV: 10.82 $\pm$ 1.82 MPa, TCXT: 11.50 $\pm$ 1.72 MPa). But, SBS of the sandblast treated groups had significantly lower values than the tribochemical silica coated groups (SALV, 1.23 $\pm$ 1.16 MPa; SAXT, 1.76 $\pm$ 1.39 MPa; p < 0.05). There was no difference between the shear bond strength by type of adhesive. In the silica coated groups, 77% of the samples showed bonding failure in the adhesive. In the sandblast treated group, all bonding failures occurred at the bracket-adhesive interface. Conclusions: The result of this study suggest that newly introduced nano-filled flowable composite resin and tribochemical silica coating application on debonded ceramic bracket bases can produce appropriate bond strengths for orthodontic bonding.

• Journal of radiological science and technology
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• v.39 no.1
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• pp.43-49
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• 2016

In this study, equivalent dose and LET (Linear Energy Transfer) calibration of CR-39 SSNTD (Solid State Nuclear Track Detector) were performed using 400 MeV/u C heavy ions in HIMAC (Heavy Ion Medical Accelerator in Chiba) for high LET radiation therapy. The irradiated CR-39 SSNDTs were etched according the etching condition of JAXA (Japan Aerospace Exploration Agency). And the etched SSNTDs were analyzed by using Image J. Determined frequency mean dose (${\bar{y_D}}$)and dose-mean lineal energy (${\bar{y_F}}$)of 400 MeV/u C are about 8.5keV/mm and 10.1 keV/mm, respectively by using the CR-39 SSNTD. This value is very similar to the results calculated by GEANT4 Monte Carlo simulation and measured with TEPC (Tissue Equivalent Proportional Counter) active radiation detector. We could determine the equivalent dose and LET calibration factors of CR-39. And we confirmed that the CR-39 SSNTD was useful for high LET radiation dosimetry in hadron radiotherapy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.2
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• pp.365-372
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• 2004

The purpose of this study was to implement HACCP system to foodservice of W and D elementary schools with joint-lunch management system in Kyungsan area. Steamed rice with squid was selected and Control Action, Monitoring Procedure and Control measure were identified based on HACCP flowchart to produce safe and healthy food. It was suggested that frozen squid must be thawed under the cold running city water and kept temperature below 1$0^{\circ}C$ and receiving/thawing procedure has to be done within 30 min. Raw vegetables must be washed under three-tube wash stand and whole prepreparation procedures should be done in 20 minutes. Clean and sanitize all the equipment and utensils before and after handling squid. Knives and cutting boards for vegetable and squid should be classified. Sauce for steamed rice with squid should be heated about 21 minutes to reach the temperature of 94$^{\circ}C$ before serving and internal temperature of food must be kept above 84.4$^{\circ}C$ during serving. The ideal temperature of kitchen should be remained 15∼18$^{\circ}C$. The underground water has to be excluded to minimize the risk of contamination in the foodservice facility and the prepreparation place must be separated with cooking place. Also, Personal hygiene Practice should be check in each stage. Further, additional research needs to be conducted to determine models for HACCP implementation for different menu.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.59-68
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• 2005

We developed a national medium vacuum standard by static expansion method. A 133 Pa capacitance diaphragm gauge was calibrated and analysed according to the document of 'Guide to the Expression of Uncertainty in Measurement' of ISO. The results showed that the expanded uncertainty of $2.628\times10^{-3}$ Pa at $95\%$ confidence level and coverage factor of k=2.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.2
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• pp.103-110
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• 2016

Fine wires made from platinum have been used as sensors to evaluate the convection performance of nanofluids. However, the wire sensor is difficult to handle due to its fragility. Additionally, an unrealistic convective heat transfer coefficient (h) is obtained if a rigorous calibration process combined with precision equipment is not used for measurement. This paper proposes a new evaluation apparatus for h of nanofluids that uses a thermistor sensor instead of the platinum wire. The working principles are also explained in detail. Validation experiments for pure engine oil comparing h from the two sensors confirmed numerous practical benefits of the thermistor. The proposed system can be used as a useful tool to justify the adoption of developed nanofluids.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.208-213
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• 2006

경사진 안창은 안창의 경사로 발의 자세를 교정함으로써 하지 통증을 완화시키는 데 사용되는 보조치료기구로 내측 경사진 안창(MWI: medially wedged insole)과 외측 경사진 안창(LWI: laterlly wedged insole)으로 나뉜다. 본 연구는 내/외측 경사진 안창이 족부압력에 미치는 영향을 정량적으로 분석하고자 한다. 분석변수는 압력중심(COP: center of pressure)의 궤적 변화, 발바닥 내 세 개 구획에 상대적으로 작용하는 수직 힘(RVF: relative vertical force) 그리고 여덟 개 해부학적 지점의 압력이다. 경사진 안창의 경사조건은 내/외측 각각 $5^{\circ},\;8^{\circ},\;15^{\circ}$이며, 경사가 없는 안창을 포함해 총 일곱 가지 안창이 실험에 사용되었다. 실험참여자로는 20대 성인 남성 10명이 참여하였다. 실험결과 앞발 누름기에서 MWI와 LWI는 모두 COP를 내측으로 이동시키고 외측 압력을 감소시켰다. 뒤축 접지기에서 MWI는 COP를 내측으로 이동 시키고 내측압력을 증가시키는 반면, LWI는 COP를 외측으로 이동시키고 외측압력을 증가시켰다. 그리고 RVF 분석결과 MWI와 LWI는 모두 앞발 부위 힘의 크기를 감소시켰고, LWI만이 발 뒤축 부위 힘의 크기를 증가시켰다.