• Journal of Electrical Engineering and Technology
• /
• v.10 no.2
• /
• pp.443-451
• /
• 2015

The stability of a multi-terminal direct current (MTDC) system is often influenced by its control strategy. To improve the stability of the MTDC system, the control strategy of the MTDC system must be appropriately adopted. This paper deals with estimating stability of a MTDC system based on the line-commutated converter based high voltage direct current (LCC HVDC) system with an inverter with constant extinction angle (CEA) control or a rectifier with constant ignition angle (CIA) control. In order to evaluate effects of two control strategies on stability, a MTDC system is tested on two conditions: initialization and changing DC power transfer. In order to compare the stability effects of the MTDC system according to each control strategy, a mathematical MTDC model is analyzed in frequency domain and time domain. In addition, Bode stability criterion and transient response are carried out to estimate its stability.

• Computers and Concrete
• /
• v.9 no.2
• /
• pp.99-118
• /
• 2012

Marine Structures are very costly and need a continuous inspection and maintenance routine. The most effective way to control the structural health is the application of an expert system that can evaluate the importance of any distress on the structure and provide a maintenance program. An extensive literature review, interviews with expert supervisors and a national survey are used to build a decision support system for concrete structures in sea environment. Decision trees are the main rules in this system. The system input is inspection information and the system output is the main cause(s) of distress(es) and the best repair method(s). Economic condition, severity of distress, distress situation, and new technologies and the most repeated classical methods are considered to choose the best repair method. A case study demonstrates the application of the developed decision support system for a type of marine structure.

• Journal of Integrative Natural Science
• /
• v.12 no.4
• /
• pp.105-115
• /
• 2019

In this paper, a prediction system is proposed to control the brightness of smart street lamps by predicting the moving path through the reduction of consumption power and information of pedestrian's past moving direction while meeting the function of existing smart street lamps. The brightness of smart street lamps is adjusted by utilizing the walk tracking vector and soft hand-off characteristics obtained through the motion sensing sensor of smart street lamps. In addition, the motion vector is used to analyze and predict the pedestrian path, and the GPU is used for high-speed computation. Pedestrians were detected using adaptive Gaussian mixing, weighted difference imaging, and motion vectors, and motions of pedestrians were analyzed using the extracted motion vectors. The preprocessing process using linear interpolation is performed to improve the performance of the proposed prediction system. Fuzzy prediction system and neural network prediction system are designed in parallel to improve efficiency and rough set is used for error correction.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.80-83
• /
• 2005

A binocular robot vision system having an autonomously moving active viewpoint is proposed. By using this active viewpoint, the system constructs a correspondence between the images of a feature points on the right and left retinas and calculates the spatial coordinates of the feature points. The system incorporates a function of detecting straight lines in an image. To detect lines the system uses Hough transform. The system searches a region surrounded by 4 straight lines. Then the system recognizes the region as a quadrangle. The system constructs a correspondence between the quadrangles in the right and left images. By the use of the result of the constructed correspondence, the system calculates the spatial coordinates of an object. An experiment shows the effect of the line detection using Hough transform, the recognition of the surface of the object and the calculation of the spatial coordinates of the object.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2418-2423
• /
• 2005

Hard Disk Drive (HDD) test system is the equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD product line, KUMI, KOREA, and shows satisfactory results.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.2424-2429
• /
• 2005

Hard Disk Drive (HDD) test system is the equipment for the final test of HDD product by iterative read/write/seek test. This paper proposes an expert system for the fault diagnosis of HDD test systems. The purposed expert system is composed with two cascade inference, fuzzy logic and conventional binary logic. The fuzzy logic determines the possibility of the system fault using the test history data, then, the binary logic inferences the fault location of the test system. The proposed expert system is tested in SAMSUNG HDD product line, KUMI, KOREA, and shows satisfactory results.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.10 no.3
• /
• pp.157-164
• /
• 2015

In this paper we propose a walking aid system for blind people by exploiting a haptic feedback equipment. The proposed system is a form of haptic feedback cane which is composed of MCU, communication module, sensing module and actuator. The proposed system recognizes obstacles around the blind by using ultrasonic sensors in the sensing module. Moreover, the system generates feedback information about the detected obstacle and then notifies the information to the blind through the actuator. The blind can notice the direction of the detected obstacle with the haptic feedback equipment and vibration motor. Futhermore, the proposed system controls a nearby IoT(Internet of Things) system by utilizing push buttons through the ZigBee communication. Finally, the blind can easily decide the direction of the obstacle without interference of terrain feature by using the proposed system.

• International Journal of Fuzzy Logic and Intelligent Systems
• /
• v.6 no.2
• /
• pp.144-149
• /
• 2006

This paper describes a novel automated analysis system for bellows of piping system. An automatic finite element (FE) mesh generation technique, which is based on the fuzzy theory and computational geometry technique, is incorporated into the system, together with one of commercial FE analysis codes and one of commercial solid modelers. In this system, a geometric model, i.e. an analysis model, is first defined using a commercial solid modelers for 3-D shell structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Delaunay triangulation technique is introduced as a basic tool for element generation. The triangular elements are converted to quadrilateral elements. Practical performances of the present system are demonstrated through several analysis for bellows of piping system.

• Proceedings of the KIEE Conference
• /
• 2001.11c
• /
• pp.107-110
• /
• 2001

Recently, there are lots of concerning on robot agent system working for itself with the trends of the research of bio-mimetic system and intelligent robot. In this paper, a virtual 3D interface system is proposed based on Internet for remote controlling and monitoring of mobile robot. The proposed system is constructed as manager-agent model. A worker can order the robot agent move to a new position by clicking the destination on virtual space of 3D graphic interface in manager. Then the robot agent move to the position automatically with avoiding collision by using range finding and autonomous control algorithm. The proposed robot agent system lets us control the mobile robot remotely located more conveniently.

• Proceedings of the KIPE Conference
• /
• 2003.07b
• /
• pp.707-710
• /
• 2003

3kW grid-connected photovoltaic (PV) system and data acquisition system are constructed for performance analysis of PV system at field demonstration test center of Gwang-Ju in Korea. As climatic and irradiation conditions are varied, operation characteristics of the PV system are collected and analyzed in data acquisition system. From these results, the performances of PV system have simulated and evaluated using simulation tool in comparison with actual value of data acquisition system of field demonstration test center. Furthermore, performance of total PV system e.g. electric power and loss factor at the site are reviewed.