• 대한기계학회논문집A
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• 제30권11호
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• pp.1348-1357
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• 2006

In a hybrid three-layer control architecture(deliberative, sequencing, and reflexive), the lowest reflexive layer consists of resources, actions, an action coordinator, and motion controllers. Because the execution of individual components in the reflexive layer should be done in real-time, each component has to be simple and, due to this reason, the Linux-RTAI(Real-Time Application Interface for Linux) has been used as an operating system. In this paper, a navigation control architecture, which combines the components in the reflexive layer and the navigation-related modules in the sequencing layer, is proposed. And then, as basic components, four actions(Goto, Avoid, Move, and EmergencyStop) are designed. Experimental results confirm the effectiveness of the proposed architecture and the performance of individual associated actions.

• 한국전자파학회논문지
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• 제13권1호
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• pp.60-67
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• 2002

본 논문에서는 발진부 귀환경로에 스위칭소자를 이용하여 최소의 소자을 사용한 소형화된 새로운 방식의 이동통신 단말기용 듀얼대역 VCO(Voltage Control Oscillator)를 제안하였다. VCO에 공진기의 Q(Quality factor)값을 정확히 모델링하기 위하여 공진기를 등가 모델하고, 이론 수치 해석하여 최적의 공진기를 설계하였다. 본 논문에서 제안된 방식을 적용하여 GSM(Global System for Mobile), DCS(Digital Cordless System) 대역의 동작 주파수를 갖는 듀얼대역 전압제어 발진기를 설계하였으며, 논문의 객관성을 입증하기 위해 제작 및 실험을 통하여 새로 제안된 방식의 듀얼대역 전압제어 발진기의 실용화가 가능함을 확인하였고, 앞으로 차세대 이동통신 기기의 고주파 부품 등에 응용될 수 있을 것이다.

• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.434-443
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• 2007

Presently, the exploration of an unknown environment is an important task for thee new generation of mobile service robots and mobile robots are navigated by means of a number of methods, using navigating systems such as the sonar-sensing system or the visual-sensing system. To fully utilize the strengths of both the sonar and visual sensing systems. This paper presents a technique for localization of a mobile robot using fusion data of multi-ultrasonic sensors and vision system. The mobile robot is designed for operating in a well-structured environment that can be represented by planes, edges, comers and cylinders in the view of structural features. In the case of ultrasonic sensors, these features have the range information in the form of the arc of a circle that is generally named as RCD(Region of Constant Depth). Localization is the continual provision of a knowledge of position which is deduced from it's a priori position estimation. The environment of a robot is modeled into a two dimensional grid map. we defines a vision-based environment recognition, phisically-based sonar sensor model and employs an extended Kalman filter to estimate position of the robot. The performance and simplicity of the approach is demonstrated with the results produced by sets of experiments using a mobile robot.

• 디지털산업정보학회논문지
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• 제8권4호
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• pp.35-41
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• 2012

Recently, universities have difficulties in operating the normal curriculum because fresher's basic academic ability is declined. It causes campus misfits so managing students is also not an easy matter. The education system that focuses only on college entrance exams is one of the reasons why this phenomenon occurred. Activity with self-directed Learning Community to know learning level themselves and execute systematic studying habit is essential for improving this problem. This activity can help students understanding and having interest in class and be motivated to study. But it had burdened tutors with submitting activity report in written form. In this paper, we suggest the Mobile Based Activity Report Submission System which can be the solution of the problem that the Self-directed Learning Community System has. This system reduces the emotional burden to write the reports and manages them efficiently.

• 제어로봇시스템학회논문지
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• 제13권8호
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• pp.726-734
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• 2007

Generally, a mobile robot is moved by original input programs. However, it is very hard for a non-expert to change the program generating the moving path of a mobile robot, because he doesn't know almost the teaching command and operating method for driving the robot. Therefore, the teaching method with speech command for a handicapped person without hands or a non-expert without an expert knowledge to generate the path is required gradually. In this study, for easily teaching the moving path of the autonomous mobile robot, the autonomous mobile robot with the function of speech recognition is developed. The use of human voice as the teaching method provides more convenient user-interface for mobile robot. To implement the teaching function, the designed robot system is composed of three separated control modules, which are speech preprocessing module, DC servo motor control module, and main control module. In this study, we design and implement a speaker dependent isolated word recognition system for creating moving path of an autonomous mobile robot in the unknown environment. The system uses word-level Hidden Markov Models(HMM) for designated command vocabularies to control a mobile robot, and it has postprocessing by neural network according to the condition based on confidence score. As the spectral analysis method, we use a filter-bank analysis model to extract of features of the voice. The proposed word recognition system is tested using 33 Korean words for control of the mobile robot navigation, and we also evaluate the performance of navigation of a mobile robot using only voice command.

• 한국멀티미디어학회논문지
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• 제14권1호
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• pp.103-111
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• 2011

기존의 스마트카드에 자바 플랫폼이 탑재된 자바 카드는 리더기를 통하여 전원이 잠시 공급될 때 어플리케이션을 적재하고 실행된다. 하지만 오늘날 여러 종류의 자바 카드는 USIM 카드와 같이 이동단말기 상에 내장되어 단말기로부터 항상 전원을 공급받을 수 있다. 이와 같이 항시 전원이 공급이 될 경우, 자바 카드들의 성능개선이 가능하다. 본 논문에서는 항시 전원 공급을 받는 자바 카드의 메모리 관리 메카니즘을 보다 효과적으로 운용함으로써 성능 향상된 애플릿 설치 및 실행이 가능한 자바카드 운영체제 시스템을 제안한다.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.159-165
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• 2008

This paper deals with the optimum high pressure control algorithm for a transcritical $CO_2$ mobile air-conditioning system with belt-driven compressor to achieve the maximum COP. The experiments were performed to find out the maximum COP conditions with various operating conditions. The experimental results showed that the COP was increased and then decreased with increase of the refrigerant high pressure for the system. Therefore the value of high pressure which has maximum COP could be selected. Furthermore, the strong (linear) relation between the optimum high pressure and the gas cooler outlet temperature was revealed, which suggests the use of a simple controller with only one parameter for the transcritical $CO_2$ cycle.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제7권3호
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• pp.176-181
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• 2007

This paper presents evolvable neural networks based on a developmental model for navigation control of autonomous mobile robots in dynamic operating environments. Bio-inspired mechanisms have been applied to autonomous design of artificial neural networks for solving practical problems. The proposed neural network architecture is grown from an initial developmental model by a set of production rules of the L-system that are represented by the DNA coding. The L-system is based on parallel rewriting mechanism motivated by the growth models of plants. DNA coding gives an effective method of expressing general production rules. Experiments show that the evolvable neural network designed by the production rules of the L-system develops into a controller for mobile robot navigation to avoid collisions with the obstacles.

• 한국인터넷방송통신학회논문지
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• 제10권4호
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• pp.91-97
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• 2010

본 논문은 전방향 이동로봇과 로봇에 탑재된 카메라를 이용한 네트워크기반 원격 감시시스템의 구현에 대하여 기술한다. 제안된 감시시스템은 기존의 건물 곳곳에 설치된 감시 카메라의 영상이 고정된 및 시야에서 침입탐지를 수행하는데 비해 이동로봇을 이용해 원격으로 로봇을 자유롭게 조종해 감시하는 것이 특징이다. 감시시스템 구현에 사용된 이동로봇은 전방향 제어가 가능한 세 개의 바퀴를 가지고 있으며, 이를 네트워크 환경에서 원격으로 제어하고 영상을 획득하기 위해 마이크로소프트사의 MSRDS를 이용해 로봇 기능들을 네트워크 노드에서 실행되는 서비스들로 구현하였다. 실험을 통해 개발된 전방향 이동로봇 원격 감시시스템은 유무선 네트워크 환경에서 자유롭게 이동로봇을 조종하며 원격 모니터링이 가능함을 보여주었다. 또한 개발된 감시시스템은 획득된 원격 영상을 네트워크에 연결된 다른 PC에서 실시간으로 전송받아 색상기만 물체탐지 및 움직임 검출을 수행하였다.

• 산업경영시스템학회지
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• 제30권2호
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• pp.29-36
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• 2007

This study was concerned about mobile web-service of a VMI in the SCM system. The VMI would be a main module part of the SCM and regarded as very important thing on supply chain. Therefore, it was essential to react in real time of materials production and situation of used auto-part in procurement company. We could find an affordable method to realize the VMI in a web service. The web service has made inter relevant enterprise easy to collaborate because of supporting most operating system and frame-work. Moreover, the use of a mobile tools was guaranteed a product recording and requirement of materials to real time in a rapid changing of production environments. The result of this research was very useful to apply the VMI system in medium and small sized auto parts company. This web service package has programmed the Visual Studio Dot Net 2003 and the MS SQL 2000 as database.