• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2006년도 춘계 국제학술대회 논문집
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• pp.77-88
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• 2006

Data Envelopment Analysis (DEA), a non-parametric productivity analysis tool, has become an accepted approach for assessing efficiency in a wide range of fields. Despite of its extensive applications, some features of DEA remain bothersome. DEA offers no guidelines to where relatively inefficient DMU(Decision Making Unit) improve since a reference set of an inefficient DMU consists of several efficient DMUs and it doesn't provide a stepwise path for improving the efficiency of each inefficient DMU considering the difference of efficiency. We aim to show that DEA can be used to evaluate the efficiency of System Integration Projects and suggest the methodology which overcomes the limitation of DEA through hybrid analysis utilizing DEA along with machine learning.

• 한국산업융합학회 논문집
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• 제26권2_2호
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• pp.359-370
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• 2023

For a vehicle to follow a reference path accurately, its position must be estimated accurately and reliably. In this paper, we propose a lateral control algorithm for autonomous navigation of a vehicle via USAT(Ultrasonic Satellite System), which is an absolute position measurement system using an ultrasonic wave and INS(Inertial Navigation System) integration. In order to estimate the vehicle's parameters, a J-turn test is used. And the autonomous navigation performances of proposed lateral control algorithm and validity of proposed lateral control algorithm are verified and evaluated by simulation and experiments.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.181-186
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• 2002

Laser welding application for car body manufacturing has many advantages in the stiffness and the lightness of vehicle, the productivity of assembly line, and the degree of freedom in design. This presentation will express the innovation of car body manufacturing including parameter optimization, process modeling, and system integration. In this application the investment for systems was cut down dramatically by real time switching over the laser path between two welding stations. Points of technical discussion are as follows: optimization of parameters such as laser power, robot speed and trajectory, compact and useful design of jig & fixture to assure welding quality for 3 sheet-layer zinc-coated steel, system integration between 4kW Nd:YAG laser device and the other systems, on-line real time welding quality monitoring system, perfect safety standards for high power laser, minimization of consumption costs such as arc lamp, protective glass for optic, etc. Laser welding has found a place on Hyundai's production plant in conjunction with the startup of mass production of new sports car, and this production system is the result of a collaboration of its engineers. Outer side sheets are joined to inner side sheets by 122 stitch welds totally. And the length is about 2.4meter.

• 제어로봇시스템학회논문지
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• 제10권9호
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• pp.785-798
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• 2004

This paper introduces the development of a range sensor based integrated navigation system for a multi-functional indoor service robot, called PSR (Public Service Robot System). The proposed navigation system includes hardware integration for sensors and actuators, the development of crucial navigation algorithms like mapping, localization, and path planning, and planning scheme such as error/fault handling. Major advantages of the proposed system are as follows: 1) A range sensor based generalized navigation system. 2) No need for the modification of environments. 3) Intelligent navigation-related components. 4) Framework supporting the selection of multiple behaviors and error/fault handling schemes. Experimental results are presented in order to show the feasibility of the proposed navigation system. The result of this research has been successfully applied to our three service robots in a variety of task domains including a delivery, a patrol, a guide, and a floor cleaning task.

• Ocean Systems Engineering
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• 제1권3호
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• pp.249-261
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• 2011

The stochastic nonlinear dynamic behavior and probability density function of ship rolling are studied using the nonlinear dynamical systems approach and probability theory. The probability density function of the rolling response is evaluated through solving the Fokker Planck Equation using the path integral method based on a Gauss-Legendre interpolation scheme. The time-dependent probability of ship rolling restricted to within the safe domain is provided and capsizing is investigated from the probability point of view. The random differential equation of ships' rolling motion is established considering the nonlinear damping, nonlinear restoring moment, white noise and colored noise wave excitation.

• Journal of Communications and Networks
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• 제11권3호
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• pp.261-270
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• 2009

We propose a tree-based integration of infrastructure networks and MANETs (TUM) to efficiently extend the scope of mobile Internet protocol to mobile ad hoc networks and devise a tree-based routing protocol (TBRP) that is suitable for the TUM architecture. Infrastructure networks have a number of fixed Internet Gateways that connect two heterogeneous networks. Mobile nodes form a number of small trees named pMANETs, each of them growing from anchor node which can communicate directly with an Internet Gateway. A new node registers with foreign agent and home agent along the tree path without resorting to an inefficient flooding. Furthermore, the TBRP sets up a routing path efficiently by exploiting the tree information without relying on flooding. We show by resorting to simulation that our approach is competitive against the conventional AODV based approach.

• 반도체디스플레이기술학회지
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• 제9권2호
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• pp.15-20
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• 2010

This paper deals with minimizing layout area of FPGA design. FPGAs are becoming increasingly important in the design of ASICs since they provide both large scale integration and user-programmability. This paper describes a method to obtain tight bound on the worst-case increase in area when drivers are introduced along many long wires in a layout. The area occupied by minimum-area embedding for a circuit can depend on the aspect ratio of the bounding rectangle of the layout. This paper presents a separator-based area-optimal embeddings for FPGA graphs in rectangles of several aspect ratios which solves the longest path problem in the constraint graph.

• ETRI Journal
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• 제45권5호
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• pp.746-757
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• 2023

This study presents a novel safe landing algorithm for urban drone deliveries. The rapid advancement of drone technology has given rise to various delivery services for everyday necessities and emergency relief efforts. However, the reliability of drone delivery technology is still insufficient for application in urban environments. The proposed approach uses the "landing angle control" method to allow the drone to land vertically and a rapidly exploring random tree-based collision avoidance algorithm to generate safe and efficient vertical landing paths for drones while avoiding common urban obstacles like trees, street lights, utility poles, and wires; these methods allow for precise and reliable urban drone delivery. We verified the approach within a Gazebo simulation operated through ROS using a six-degree-of-freedom drone model and sensors with similar specifications to actual models. The performance of the algorithms was tested in various scenarios by comparing it with that of stateof-the-art 3D path planning algorithms.

• 재활복지
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• 제18권4호
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• pp.47-74
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• 2014

본 연구는 척수장애인의 사회통합에 미치는 요인을 연구함으로써 사회복지실천 현장에서 척수장애인의 사회통합을 위한 대안 마련에 기초자료를 제공하고자 시도되었다. 본 연구의 목적을 달성하고자 한국척수장애인협회의 산하조직 13개 지역협회의 협조를 얻어 각 지역 협회에 배포한 390부 중 회수된 설문지 335부 중에서 답변이 불성실한 21부를 제외하고 304부를 사용하였다. 척수장애인의 사회통합에 영향을 미치는 요인에 관한 구조방정식 최종모형의 경로별 효과분석과 유의성 검증을 토대로 신체 심리적 요인, 경제적 요인, 사회적 지지가 척수장애인의 사회통합에 미치는 영향을 비교한 결과 삶의 만족도는 신체 심리적 요인, 사회적 지지와 사회통합을 부분매개 하는 것으로 나타났다. 또한 경제적 요인과 사회통합에는 완전매개 하는 것으로 나타났다. 이러한 결과는 척수장애인의 삶의 만족도를 높이면 척수장애인의 사회통합의 목적을 달성할 수 있을 것이라는 것을 시사하고 있다.

• 국제교류와 융합교육
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• 제3권1호
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• pp.29-50
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• 2023

국가 혁신 추진 전략에 따라 중국의 경제는 고속 발전 시기에 접어들었고 각 업계에서 기술에 대해 더 많은 요구를 제기하였다. 이러한 새로운 사회 환경에 직면함에 있어, 중국의 대학은 더욱 교육의 질을 높여야 한다. 그러기 위해서는 창업교육을 전문교육과 융합시키면 학생들의 혁신 능력을 더욱 양성할 수 있고, 대학교와 기업의 협력과 교류를 강화할 수 있다. 이에 본 연구는 안휘성에 소속하는 대학교의 교사와 학생을 연구 대상으로 설문조사를 통하여 창업교육과 전문교육의 융합 현황을 파악하는 데 목적을 두고 있다. 이렇게 얻은 설문조사 데이터는 설문조사 설문지의 데이터는 통계 소프트웨어 SPSS26.0을 사용하여 분석하였다. 설문 결과의 신뢰성 분성과 검증을 하였으며, 이에 일원 분산 분석을 하였다. 이를 위해 설문지 작성 시 성별, 학력, 직업배경, 가족기업가정신의 4가지 통제변수를 선정하였다. 또한 회귀 분석을 하여 변수 간의 상관 관계를 확인하였다. 그 연구 결과, 중국의 대학생들은 창업에 대한 인식이 부족하고 교육과정 융합 상황은 이상적이지 않으며 교사팀 구성이 불균형한 것으로 나타났다. 또한 실천 플랫폼의 실행 효과도 좋지 않은 것으로 나타났다. 따라서 이러한 결과를 바탕으로 앞으로 국가 직업교육 발전 계획을 결합하여 관련된 대책을 제언하였다. 또한 이 자료가 직업 교육 발전에 대한 기초 자료로서 대학교의 창업교육과 전문교육의 융합에 새로운 시사점을 제공할 수 있기를 기대한다.