• 로봇학회논문지
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• 제5권2호
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• pp.102-109
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• 2010

In this study, an anthropomorphic robot Hand, called "SKKU Hand III" is presented. The hand has thirteen DOF(Degree-Of-Freedom) and is designed based on the skeletal structure of the human hand. Each finger module(except thumb module) has three DOF and four joints with a saddle joint mechanism which has two DOF at the base joint. Two distal joints of the finger module are mechanically coupled by a timing belt and pulleys. The thumb module is composed of a finger module and an additional actuator, which makes it possible to realize the opposition between the thumb and the other fingers. In addition, the palm DOF of the human hand is mimicked with a spatial link mechanism between the index finger and the thumb. Thus, it can grasp objects more stably and more strongly. For the modularization of the robotic hand all the driving circuits are embedded in the hand, and only the communication lines supporting CAN protocol with DC power cable are given as an interface. Therefore, it is possible to apply it to any robot system the interface. To validate the feasibility of the SKKU Hand III, a series of the representative grasp experiments such as power, precision, intermediate grasp etc. are carried out with the object around us and its operation is demonstrated.

• 한국산업융합학회 논문집
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• 제27권3호
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• pp.629-634
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• 2024

The Korea Research Institute of Ships and Ocean Engineering (KRISO) has developed a test module that can vertically ascend and descend with a buoyancy engine to verify the performance of the developed buoyancy engine. The independent test module has been tested in the Ocean Engineering Basin(C.M.Lee et al., 2023). After that, more tests were performed in the Deep Ocean Engineering Basin and at sea. In the 50-meter depth pit test of the Deep Ocean Engineering Basin, there were no problems with the ascent and descent operations, but the buoyancy engine was not properly maintained due to various problems in the independent test module, resulting in a difference between the calculated results using the solution of the equations of motion and the actual measurement results. The East Sea test was conducted at a depth of approximately 110 meters north-east of Pohang, with a dive to 100 meters. The difference between the pressure sensor value and the calculated value was observed, but after checking the results of the underwater position tracking device(USBL, Ultra Short Base Line system), it was estimated that the difference was caused by the influence of the current.

• 한국진공학회지
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• 제18권3호
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• pp.151-163
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• 2009

유체 모델을 기반으로 하는 국내의 유도 결합 플라즈마원의 시뮬레이터 개발 현황을 정리하였다. 전체 시뮬레이터를 구성하는 각 부분으로서, 전자 가열, 하전 입자 및 중성종 수송, sheath를 포함한 표면 반응, 그리고 GUI (Graphic User Interface) 및 전후처리기 등의 순으로 설명되었다. 현재까지 시뮬레이터에 구현된 화학 반응 데이터와 swarm 데이터도 정리하여 보았고, 앞으로의 개발 방향을 전망하여 보았다.

• 한국컴퓨터정보학회논문지
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• 제9권4호
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• pp.157-165
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• 2004

본 논문에서는 현재 증가하고 있는 웹 서비스 공격을 정확하고 빠르게 탐지할 수 있고, 잘못된 공격탐지를 줄여줄 수 있는 웹서버 보안관리시스템을 제안한다. 이 시스템은 여러 단위보안모듈들의 결과를 실시간으로 수집하고 상호연관성 분석과정을 통해 탐지의 정확성을 향상시킨다. 단위보안모듈은 네트웍기반 침입탐지시스템 모듈, 파일무결성 검사 모듈, 시스템로그분석 모듈 그리고 웹로그분석 모듈로 구성되며, 그리고 각각의 단위보안모듈들의 결과에 연관성을 부여하여 실시간으로 분석하는 상호연관성 분석 모듈이 있다. 제안한 시스템은 공격탐지의 정확성 뿐 아니라 단위보안모듈의 추가 그리고 상호연관성 분석의 범위확장이 용이한 프레임워크를 제공한다. 그리고 제안한 시스템의 단위보안모듈 중 침입탐지시스템 모듈은 다중 쓰레드 기반으로 Snort를 재구성하여 보다 빠른 공격 탐지 시간을 갖는다. 처리량이 많은 단위보안모듈의 처리시간을 단축함으로서 웹서버 보안관리시스템 처리 성능을 향상시킬 수 있다.

• 한국태양에너지학회 논문집
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• 제33권3호
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• pp.58-66
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• 2013

Recently, PV module that the most important part of the photovoltaic system is more widened to lower manufacturing costs for module. However, the broad PV module results to the serious mechanical damage corning from installation circumstances such as snow, wind etc of snow and finally lead to the dramatic degradation of the electrical behavior of PV module. In this paper, 3 kinds of PV modules that consist of the different thickness and area of front glass and the diverse cross sectional structures of the frame are prepared for this experiment. The drooped length and electrical outputs of the PV modules are measured by means of applying 600Pa mechanical load to the PV modules from 1200Pa to 5400Pa base on the mechanical load test procedure of K SC IEG 61215 standard. The simulation data are obtained by the simulation tool as ANSYS and those are validate by comparing with the those experimental results figure out relations between the deformation and the constituent part of PV module.

• Structural Engineering and Mechanics
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• 제69권4호
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• pp.407-416
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• 2019

This paper develops a wireless sensor for online fatigue crack detection and failure warning based on crack-induced nonlinear ultrasonic modulation. The wireless sensor consists of packaged piezoelectric (PZT) module, an excitation/sensing module, a data acquisition/processing module, a wireless communication module, and a power supply module. The packaged PZT and the excitation/sensing module generate ultrasonic waves on a structure and capture the response. Based on nonlinear ultrasonic modulation created by a crack, the data acquisition/processing module periodically performs fatigue crack diagnosis and provides failure warning if a component failure is imminent. The outcomes are transmitted to a base through the wireless communication module where two-levels duty cycling media access control (MAC) is implemented. The uniqueness of the paper lies in that 1) the proposed wireless sensor is developed specifically for online fatigue crack detection and failure warning, 2) failure warning as well as crack diagnosis are provided based on crack-induced nonlinear ultrasonic modulation, 3) event-driven operation of the sensor, considering rare extreme events such as earthquakes, is made possible with a power minimization strategy, and 4) the applicability of the wireless sensor to steel welded members is examined through field and laboratory tests. A fatigue crack on a steel welded specimen was successfully detected when the overall width of the crack was around $30{\mu}m$, and a failure warnings were provided when about 97.6% of the remaining useful fatigue lives were reached. Four wireless sensors were deployed on Yeongjong Grand Bridge in Souht Korea. The wireless sensor consumed 282.95 J for 3 weeks, and the processed results on the sensor were transmitted up to 20 m with over 90% success rate.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.331-332
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• 2012

• 대한기계학회논문집A
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• 제35권4호
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• pp.409-415
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• 2011

감시 정찰용 짐발 구조 시스템은 베어링들과 다른 기계 요소들로 구성된 복잡한 기계 장치이다. 이 시스템은 크게 카메라부와 카메라부를 지지하는 안정화 짐발로 나눌 수 있다. 영상 정보 취득을 위한 비행 중 짐발 구조 시스템은 정찰기로부터 전달되는 광범위한 진동수를 갖는 심각한 가진을 받게 된다. 비록 정찰기로부터 전달되는 안정화 짐발의 기초 가진이 카메라부의 진동을 유발할지라도 카메라부는 정확하고 선명한 영상을 기록하여야만 한다. 그러므로 카메라부를 포함한 전체 짐발 구조시스템의 고유진동수와 고유진동 모드를 분석하는 것이 중요하다. 이에 본 연구에서는 베어링들의 효과를 고려한 시스템의 진동 특성 해석을 유한요소법에 의해 수행하였다. 뿐만 아니라, 0 Hz ~ 500 Hz 의 진동수 영역에서 조화응답해석을 통해 카메라부의 가속도 전달률을 계산하였다.

• ETRI Journal
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• 제35권3호
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• pp.378-385
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• 2013

An S-band multifunction chip with a simple interface for an active phased array base station antenna for next-generation mobile communications is designed and fabricated using commercial 0.5-${\mu}m$ GaAs pHEMT technology. To reduce the cost of the module assembly and to reduce the number of chip interfaces for a compact transmit/receive module, a digital serial-to-parallel converter and an active bias circuit are integrated into the designed chip. The chip can be controlled and driven using only five interfaces. With 6-bit phase shifting and 6-bit attenuation, it provides a wideband performance employing a shunt-feedback technique for amplifiers. With a compact size of 16 $mm^2$ ($4mm{\times}4mm$), the proposed chip exhibits a gain of 26 dB, a P1dB of 12 dBm, and a noise figure of 3.5 dB over a wide frequency range of 1.8 GHz to 3.2 GHz.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.452-458
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• 2007

The vertical extension of a building in general remodeling process increases both gravity and seismic loads by simply adding masses to the building. In this study, a vertical extension structural module (VESM) is proposed for enhancing seismic performance of the existing buildings by utilizing the story-increased parts. The proposed VESM is composed of steel column, steel beam, and beam-end rotational damper. The steel columns are connected to the shear walls and transfer the wall rotation in out-of plane to the steel beam, and then the beam-end rotational damper dissipates the earthquake-induced energy. Numerical analysis result from a cantilever beam of which end-rotation is restricted by rotational damper indicates that the displacement, base shear, and base overturning moment of the existing structures showing cantilever behavior can be significantly reduced by using the proposed method. Also, it is observed that friction-type rotational damper is effective than viscous one.