• Journal of Ocean Engineering and Technology
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• v.33 no.6
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• pp.632-640
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• 2019

Desalination plant ships have been recently regarded as one of the probable solutions for drought seasons in many countries. Because desalination plants should be mounted on the desalination ships and special purpose storages such as salty waste water tanks are necessary, onboard and compartment arrangements would be distinguished from those of other conventional commercial ships. This paper introduces some basic design procedure including resistance/propulsion and seakeeping performances. The ship lines were improved step by step after modification of the ship lines and verification of resistance/propulsion performances using computational fluid dynamics (CFD). After finalization of the ship lines, the seakeeping performance was also evaluated to check motion behaviors and drive wave-induced loads such as the wave shear force and bending moment. It was proved that the predicted long-term vertical wave shear force and bending moment were significantly less than the rule-based ones, thus it is expected that the deliverables of this study will reduce the construction cost of desalination plant ships.

• Korean Journal of Materials Research
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• v.10 no.5
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• pp.364-368
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• 2000

SiC fiber reinforced $Si_3N_4$ matrix composites combined with electrical conductive phases of carbon fiber and WC powder fabricated by hot pressing at 1773K. The ability to predict fracture in the ceramic matrix composites was evaluated by measuring simultaneous load-deflection and electrical resistanc difference-deflection curves in four point bending tests. The changes in electrical resistance differences closely corresponded to the fracture behavior of the composites. Different electrical conductive phases are suited to predicting different stages and rates of fracture. These obsevations how that it is possible to perform "in situ" fracture detection in ceramic composites.

• Journal of the Korea Institute of Building Construction
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• v.6 no.4 s.22
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• pp.85-92
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• 2006

Urethane, epoxy, acrylic have common property to adhere on the concrete dried surface in the waterproofing materials at present. In the wet condition, however, the materials such as urethane, epoxy, acrylic need a long hardening time and it become a reason of water leakage as the materials breaking down. it is one of the problem to adhere to the substrate. Therefore, in this thesis, I focused to assure the structural safety and durability and quality for waterproofing and safe of construction cost by cut down the cost of labor and reduce the term of works as searching the application of field condition for high adhesive spray type of degenerated and rubberized asphalt membrane material.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1619-1620
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• 2015

KS C IEC 62561-2 표준은 피뢰시스템 구성요소로서의 도체 및 접지극에 관한 요구사항 및 시험에 대하여 규정되어 있다. 외부 피뢰 구성자재는 대기 중 혹은 대지에 직접 노출되어 있기 때문에 전기적 성능과 기계적 성능을 모두 만족해야 한다. 또한 피뢰도체와 접지극은 재질과 크기, 형태가 모두 다르기 때문에 각각의 요구사항에 부합할 수 있는 성능을 지녀야 한다. 본 논문에서는 일반적으로 많이 쓰이는 재질과 단면적을 가지는 접지봉으로 성능시험을 진행하였으며, 접지봉의 재료는 스테인레스강에 구리를 코팅한 동복강선으로 구성된다. 시험 결과 점착 시험 및 굽힘 시험에서 모두 크랙 및 코팅이 벗겨지는 것을 확인할 수 있었다. 코팅에 크랙 혹은 벗겨짐이 발생하면 지중에서 접지극의 부식이 진행되고, 접지저항이 높아져 전기적 성능을 저하시키는 결과를 야기한다. 때문에 스테인레스강에 구리 혹은 아연 등을 코팅하는 과정에서 벗겨짐이 없도록 점착 성능이 개선되어야 한다고 판단된다.

• Proceedings of the Korea Information Processing Society Conference
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• 2022.11a
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• pp.661-663
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• 2022

이 논문에서는 변형 가능한 햅틱 컨트롤러와 포스 피드백 장치를 이용한 치과 수술 시뮬레이션 시스템을 제안한다. 이 시스템은 가상 환경에서 매복 사랑니 발치 수술을 수행하도록 설계되었다. 햅틱 하드웨어들은 신체와 수술도구의 상대적 위치를 계산하여 충돌여부를 파악하고 저항감과 진동감을 제공한다. 특히 길이 변화, 굽힘 발생과 같은 변형이 가능한 햅틱 컨트롤러는 사용하는 수술도구에 따라 느껴지는 촉감을 표현할 수 있다. 정교한 3 차원 모델로 구강내부와 치과용 수술도구를 표현한 후 햅틱 컨트롤러의 움직임과 버튼 클릭 등의 입력 값을 전달하는 모듈을 통해 가상 객체와 상호 작용하고 이에 대한 햅틱 피드백을 컨트롤러로 전달하여 사용자에게 현실적인 수술 경험을 제공한다.

• Science of Emotion and Sensibility
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• v.25 no.4
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• pp.119-128
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• 2022

This study analyzes the effects of the number of angles and bends on resistance in a conductor-embroidered stitch circuit for efficient power transfer through a conductor of wearable energy harvesting to study changes in power lost through connection with actual solar panels. In this study, the angle of the conductive stitch circuit was designed in units of 30˚, from 30˚ to 180˚, and the resistance was measured using an analog Discovery 2 device. The measured resistance value was analyzed, and in the section of the angle where the resistance value rapidly changes, it was measured again and analyzed in units of 5˚. Following this, from the results of the analysis, the angle at which the tension was applied to the stitch converges was analyzed, and the resistance was measured again by varying the number of bends of the stitch at the given angle. The resistance decreases as the angle of the stitch decreases and the number of bends increases, and the conductor embroidery stitch can reduce the loss of power by 1.61 times relative to general embroidery. These results suggest that the stitching of embroidery has a significant effect on the power transfer in the transmission through the conductors of wearable energy harvesting. These results indicate the need for a follow-up study to develop a conductor circuit design technology that compares and analyzes various types of stitches, such as curved stitches, and the number of conductors, so that wearable energy harvesting can be more efficiently produced and stored.

• 전자공학회논문지 IE
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• v.43 no.4
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• pp.28-36
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• 2006

In this paper, an algorithm to classify the 4 motions of arm and a control system to position control the prosthesis are studied. To classify the 4 motions, we use flex sensors which is electrical resistance type sensor that can measure warp of muscle. The flex sensors are attached to the biceps brchii muscle and coracobrachialis muscle and the sensor signals are passed the sensing system. 4 motion of the forearm - flexion and extension, the pronation and supination are classified from this. Also position of forearm is measured from the classified signals. Finally, A two D.O.F prosthesis arm with RC servo-motor is designed to verify the validity of the algorithm. At this time, fuzzy controller is used to reduce the position error by rotary inertia and noise. From the experiment, the position error had occurred within about 5 degree.

• Bulletin of the Society of Naval Architects of Korea
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• v.27 no.1
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• pp.24-34
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• 1990

In this paper, the formulation of a new simplified finite element is made to analyze the ultimate strength of damaged tubular members subjected to combined axial force and end moment. A damaged tubular member that has the bending deformation and the local dent is modeled by beam elements. Tangent elastic stiffness matrix of a beam element which contains the effect of the geometric nonlinearity is derived by using the updated Lagrangian approach. Here the contribution of the stiffness in the dented area is neglected since its resistance against the external loads is considered to be small. A fully plastic interaction curve of the element under combined loads taking account of the local dent effect is selected as a yielding criterion at each nodal point. Also tangent elasto-plastic stiffness matrix of the element is formulated by plastic node method. Comparison with the present solution and the existing experimental results is made showing that the present method gives quite an accurate solution.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.269-281
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• 2008

Fatigue or overload can result in mechanical problems of implant components. The mechanical strength in the implant system is dependent on several factors, such as screw and fixture diameters, material, and design of the fixture-abutment connection and abutment. In these factors, the last rules the strength and stability of the fixture-abutment assembly. There have been some previous reports on the mechanical strength of the fixture-abutment assembly with the compressive bending test or short-term cyclic loading test. However, it is restrictive to predict the long-term stability of the implant system with them. The purpose of this study was to evaluate the influence of the design of the fixture-abutment connection and abutment on the mechanical strength and failure mode by conducting the endurance limit test as well as the compressive bending strength test. Tests were performed according to a specified test(ISO/FDIS 14801) in 4 fixture-abutment assemblies of the Osstem implant system: an external butt joint with Cemented abutment (group BJT), an external butt joint with Safe abutment (group BJS), an internal conical joint with Solid abutment (group CJO), and an internal conical joint with ComOcta abutment (group CJT). The following conclusions were drawn within the limitation of this study. Compressive bending strengths were decreased in order of group BJS(1392.0N), group CJO(1261.8N), group BJT(1153.2N), and group CJT(1110.2N). There were no significant differences in compressive bending strengths between group BJT and group CJT(P>.05). Endurance limits were decreased in order of group CJO(600N), group CJT(453N), group BJS(360N), and group BJT(300N). 3. Compressive bending strengths were influenced by the connection and abutment design of the implant system, however endurance limits were affected more considerably by the connection design.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.21-29
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• 2016

In this paper, we developed a flexible transparent capacitive pressure sensor which can recognize X and Y coordinates and the size of force simultaneously by sensing a change in electrical capacitance. The flexible transparent capacitive pressure sensor was composed of 3 layers which were top electrode, pressure sensing layer, and bottom electrode. Silver nanowire(Ag NW)/poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) hybrid film was used for top and bottom flexible transparent electrode. The fabricated capacitive pressure sensor had a total size of 5 inch, and was composed of 11 driving line and 19 sensing line channels. The electrical, optical properties of the Ag NW/PEDOT:PSS and capacitive pressure sensor were investigated respectively. The mechanical flexibility was also investigated by bending tests. Ag NW/PEDOT:PSS exhibited the sheet resistance of $44.1{\Omega}/square$, transmittance of 91.1%, and haze of 1.35%. Notably, the Ag NW/PEDOT:PSS hybrid electrode had a constant resistance change within a bending radius of 3 mm. The bending fatigue tests showed that the Ag NW/PEDOT:PSS could withstand 200,000 bending cycles which indicated the superior flexibility and durability of the hybrid electrode. The flexible transparent capacitive pressure sensor showed the transmittance of 84.1%, and haze of 3.56%. When the capacitive pressure sensor was pressed with the multiple 2 mm-diameter tips, it can well detect the force depending on the applied pressure. This indicated that the capacitive pressure sensor is a promising scheme for next generation flexible transparent touch screens which can provide multi-tasking capabilities through simultaneous multi-touch and multi-force sensing.