• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1983-1989
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• 2005

Industrial robots are powerful, extremely accurate multi-jointed systems, but they are heavy and highly rigid because of their mechanical structure and motorization. Therefore, sharing the robot working space with its environment is problematic. A novel pneumatic artificial muscle actuator (PAM actuator) has been regarded during the recent decades as an interesting alternative to hydraulic and electric actuators. Its main advantages are high strength and high power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available and cheap power source, inherent safety and mobility assistance to humans performing tasks. The PAM is undoubtedly the most promising artificial muscle for the actuation of new types of industrial robots such as Rubber Actuator and PAM manipulators. However, some limitations still exist, such as the air compressibility and the lack of damping ability of the actuator bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, the nonlinearities in the PAM manipulator still limit the controllability. Therefore, it is not easy to realize motion with high accuracy and high speed and with respect to various external inertia loads in order to realize a human-friendly therapy robot To overcome these problems a novel controller, which harmonizes a phase plane switching control method with conventional PID controller and the adaptabilities of neural network, is newly proposed. In order to realize satisfactory control performance a variable damper - Magneto-Rheological Brake (MRB) is equipped to the joint of the manipulator. Superb mixture of conventional PID controller and a phase plane switching control using neural network brings us a novel controller. This proposed controller is appropriate for a kind of plants with nonlinearity uncertainties and disturbances. The experiments were carried out in practical PAM manipulator and the effectiveness of the proposed control algorithm was demonstrated through experiments, which had proved that the stability of the manipulator can be improved greatly in a high gain control by using MRB with phase plane switching control using neural network and without regard for the changes of external inertia loads.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2004년도 제5회 정기학술발표대회 논문집
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• pp.561-564
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• 2004

국내외에서는 크랙실링 공법의 이점 및 도로면 유지보수 공사의 위험 요소를 인식하여 90년대 초반부터 크랙실링 자동화 장비 개발을 위한 연구를 진행하여 왔다. 기존 문헌 고찰과 도로면 크랙실링 자동화 장비(Automated Pavement Crack Sealer; APCS)의 실험실 및 현장 실험 결과, 도로면에 존재하는 크랙 네트워크를 자동으로 탐지하고 모델링하는 과정의 속도와 정확성을 향상시키는 것은 개발된 크랙실링 자동화 장비의 실용화를 위해 매우 중요한 요인으로 인식되었다 그러나, CCD 카메라를 통해 습득된 도로면 영상에서 크랙 네트워크를 완전 자동으로 인식하는 기술은 일반적인 영상 인식 분야에서 보다 외부 환경적인 요인으로 인해 낮은 인식률을 가지고 있다 본 연구를 통해 기존에 개발된 APCS 머신비전 알고리즘의 경우 도로면 영상의 환경 요인에 의해 발생된 문제점들을 많이 해결하였으나 실용화 단계에서 요구되는 크랙 인식률에는 도달하지 못하였다. 따라서, 본 연구의 목적은 기존 APCS 머신 비전 알고리즘의 완전 자동화 방식 크랙 탐지 및 모델링 알고리즘의 문제점을 분석하고 신경망 학습 기법을 이용한 크랙 인식 알고리즘을 개발하는 것이다.

• Archives of Plastic Surgery
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• 제33권2호
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• pp.181-186
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• 2006

Myocutaneous flaps have improved the management of soft tissue defects on buttocks and lower extremity. However, there are several inherent disadvantages of muscle flaps such as functional deficits of the donor sites and the bulkiness at the recipient site. To overcome these disadvantages, we have used perforator-based fasciocutaneous rotation flaps for reconstruction of the buttock and lower extremity defects. From March 2003 to February 2005, we have treated 14 patients using perforator-based fasciocutaneous rotation flaps. 10 flaps were based on perforators of the gluteus maximus muscle, and 4 flaps were nourished by perforators from the tibialis anterior and posterior system. The mean postoperative follow-up period was about 1 year. The technique involves localization of the flap perforators preoperatively with a Doppler. The flaps were elevated superficial to the fascia with preservation of one to three perforators. The donor site is then closed primarily. All flaps completely survived and there was no perioperative complications. There was no functional disability of the donor area with esthetically pleasing results. Perforator-based fasciocutaneous rotation flaps for the reconstruction of buttock and lower extremity defects are excellent alternatives to musculocutaeous flaps. The vascularity of the flaps is robust and dissection is technically easy. Perforator flaps do not require sacrificing muscles, but provide sufficient volume and are durable Furthermore, these flaps result in less scar formation and allow more liberal dissection with safety. We conclude that perforator-based fasciocutaneous rotation flaps are very useful for reconstruction of the buttock and lower extremity.

• 한국임상약학회지
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• 제24권3호
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• pp.219-228
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• 2014

Objectives: This paper was aimed to investigate the adhesion control standards of pain relieving patch (PRP) drugs and to survey it's adverse effects on the skin of patients for safe use of PRP drugs. Methods: In this study, the related documents of PRP drugs of Korea pharmacopoeia (KP), United States pharmacopoeia (USP), Japanese Pharmacopoeia (JP), European pharmacopoeia (EP), and information web sites of the Ministry of Food and Drug Safety (MFDS) were surveyed. Also, the past and current labeling of PRP drugs marketed in the pharmacy was investigated and compared. Results: In KP and JP, the lower limit standard for PRP's adhesion control is established, but the upper limit standard is not designated. In USP and EP, neither the lower nor upper limit standard is established. The main reasons of skin adverse effects are considered as inherent adverse reactions of the applied drugs for PRP. Another reason is involved in patient's medication mistakes related to PRP's adhesion control, respiratory depression of skin according to physical skin closure, and microbial growth, etc. Conclusion: For safe use of PRP drugs, we proposed ensured guidelines like additional instructions of pharmacist's prescription and detailed labeling systems for usage of PRP drugs applied on skin.

• 한국실내디자인학회논문집
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• 제20권4호
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• pp.191-200
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• 2011

Street furniture such as benches, streetlamps, and shades which are easily accessible in cities has contributed to the promotion of active, lively environment for people living in cities. Furthermore, they make the characteristics of specific regions and cities, and are valued as a communication interface to restore the relationships between people and cities. The street furniture design with inherent publicness is an essential element for leisurely life and refined image of modern people who have experienced severance and mental poverty in uniform, vertical modern city space with the development of advanced science and technology. The purpose of this study is to analyze the new design approaches to street furniture which plays an important role in the determination of the images of modern city environment and to examine the characteristics and trends of such designs. First, in accordance with the flow of studies from publicness and public space to street furniture, the concept and meaning of publicness which is the basic element of public space were identified through theoretical examination, and the characteristics and roles of modern public space were analyzed through literature review, data review, and international cases. Based on the results of this theoretical analysis, the concept and meaning elements, function elements, and design elements of the street furniture which was planned in accordance with the goal and functions of public space were identified. For the meaning elements of street furniture design, fun, health, culture, sustainability, and vitalization were identified. For the function elements of street furniture design, convenience, safety, and delivery were identified. As the characteristics of modern street furniture design, convergent, green, digilog, functional, and universal designs were analyzed. This study is meaningful in that it recognized the roles of street furniture in modern public space as a concrete, practical environmental design element and estimated the development directions of street furniture design in public space.

• Journal of Radiation Protection and Research
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• 제38권3호
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• pp.157-165
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• 2013

To determine the factors affecting the external radiation dose rates of patients undergoing PET-MRI examinations and to assess the trends of these differences, we measured the changes in the dose rates of $^{18}F$-FDG during a set period of time for each body region. Consistent with theoretical predictions, the dose rate decreased over time in patients undergoing PET-MRI examinations. Furthermore, immediately after the $^{18}F$-FDG injection, the dose rate in the chest region was the highest, followed by the abdominal region, the head region, and the foot region. The dose rate decreased drastically as time passed, by 2.47-fold, from $339.23{\pm}74.70mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection to $102.71{\pm}26.17mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. In the foot region, there were no significant changes over time, from $32.05{\pm}20.23mSv\;h^{-1}$ ($6.73{\pm}5.79$ min) at the time point immediately after the $^{18}F$-FDG injection, to $23.89{\pm}9.14mSv\;h^{-1}$ ($136.11{\pm}25.64$ min) after the examination. The dose rate is dependent on the individual characteristics of the patient, and differed depending on the body region and time point. However, the dose rates were higher in patients who had a lower body weight, shorter stature, fewer urinations, lower fluid intake, and history of diabetes mellitus. To decrease radiation exposure, it is difficult or impossible to change factors inherent to the patient, such as sex, age, height, body weight, obesity, and history of diabetes mellitus. However, factors which can be changed, such as the $^{18}F$-FDG dose, fasting time, fluid intake, number of urinations, and contrast agent dose can be controlled to minimize the external radiation exposure of the patient.

• Earthquakes and Structures
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• 제11권6호
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• pp.1001-1025
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• 2016

Building structures generally have inherent low damping capability and hence are vulnerable to seismic excitations. Control devices therefore play a useful role in providing safety to building structures subject to seismic events. In recent years semi-active dampers have gained considerable attention as structural control devices in the building construction industry. Magneto-rheological (MR) damper, a type of semi-active damper has proven to be effective in seismic mitigation of building structures. MR dampers contain a controllable MR fluid whose rheological properties vary rapidly with the applied magnetic field. Although some research has been carried out on the use of MR dampers in building structures, optimal design of MR damper and combined use of MR and passive dampers for real scale buildings has hardly been investigated. This paper investigates the use of MR dampers and incorporating MR-passive damper combinations in building structures in order to achieve acceptable levels of seismic performance. In order to do so, it first develops the MR damper model by integrating control algorithms commonly used in MR damper modelling. The developed MR damper is then integrated in to the seismically excited structure as a time domain function. Linear and nonlinear structure models are evaluated in real time scenarios. Analyses are conducted to investigate the influence of location and number of devices on the seismic performance of the building structure. The findings of this paper provide information towards the design and construction of earthquake safe buildings with optimally employed MR dampers and MR-passive damper combinations.

• 대한조선학회논문집
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• 제34권4호
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• pp.1-11
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• 1997

바지(barge)선이 예인선에 의해 예인삭으로 예인될때 예인시스템의 특성상 yaw운동이 일어나 큰 sway운동이 발생할 수 있다. 특히, 바람이나 파랑들의 외력의 작용에 의해 바지선이 과대한 운동을 일으키게 되어 예인이 곤란하거나, 심할경우 예인선이나 예인물이 전복되는 사례가 보고되고 있다. 따라서 예인물의 침로 안정성은 주변 항해 선박의 안정성과도 관계되어 여러가지 측면에서 중요한 문제로 다루어져 왔다. 본 연구는 8, 000톤급 바지선의 침로 안정성에 관한 회류수조와 예인수조의 시험 결과이다. 여러가지 형태의 스케그(skeg)를 바지선의 선미부에 부착하여 정수 및 불규칙파에서 침로안정성 시험을 수행하였다. 8,000톤급 바지선이 스케그 부착없이 예인선으로 예인될때 sway 운동의 진폭은 바지선폭의 약 10배정도인것이, 효과적인 스케그의 부착으로 진폭을 0으로 만들어 침로 안정성을 유지할수있음을 보였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.95.1-95.1
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• 2012

Very High Temperature gas cooler Reactor (VHTR) has been considered as one of the most promising nuclear reactor because of many advantages including high inherent safety to avoid environmental pollution, high thermal efficiency and the role of secondary energy source. The TRISO coated fuel particles used in VHTR are composed of 4 layers as OPyC, SiC, IPyC and buffer PyC. The significance of CVD-SiC coatings used in tri-isotropic(TRISO) nuclear coated fuel particles is to maintain the strength of the whole particle. Various methods have been proposed to evaluate the mechanical properties of CVD-SiC film at room temperature. However, few works have been attempted to characterize properties of CVD-SiC film at high temperature. In this study, micro tensile system was newly developed for mechanical characterization of SiC thin film at elevated temperature. Two kinds of CVD-SiC films were prepared for micro tensile test. SiC-A had [111]-preferred orientation, while SiC-B had [220]-preferred orientation. The free silicon was co-deposited in SiC-B coating layer. The fracture strength of two different CVD-SiC films was characterized up to $1000^{\circ}C$.The strength of SiC-B film decreased with temperature. This result can be explained by free silicon, observed in SiC-B along the columnar boundaries by TEM. The presence of free silicon causes strength degradation. Also, larger Weibull-modulus was measured. The new method can be used for thin film material at high temperature.

• Bulletin of the Korean Chemical Society
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• 제34권11호
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• pp.3301-3306
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• 2013

This paper aims to address the cellular toxicity of ultra-pure titanium dioxide ($TiO_2$) and zinc oxide (ZnO) nanoparticles (NPs) frequently employed in sunscreens as inorganic physical sun blockers to provide protection against adverse effects of ultraviolet (UV) radiation including UVB (290-320 nm) and UVA (320-400 nm). In consideration that the production and the use of inorganic NPs have aroused many concerns and controversies regarding their safety and toxicity and that microsized $TiO_2$ and ZnO have been increasingly replaced by $TiO_2$ and ZnO NPs (< 100 nm), it is very important to directly investigate a main problem related to the intrinsic/inherent toxicity of these NPs and/or their incompatibility with biological objects. In the present study, we took advantage of the laser-assisted method called laser ablation for generation of $TiO_2$ and ZnO NPs. NPs were prepared through a physical process of irradiating solid targets in liquid phase, enabling verification of the toxicity of ultra-pure NPs with nascent surfaces free from any contamination. Our results show that $TiO_2$ NPs are essentially non-poisonous and ZnO NPs are more toxic than $TiO_2$ NPs based on the cell viability assays.