• The Journal of Engineering Geology
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• v.1 no.1
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• pp.85-108
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• 1991

Marine seismic processing is characterized by a great amount of data, several professional processing steps, and various parameters to be decided in each step. In general, adequate processing sequence and optimum parameters are obtained through test processing with sample set of data representing the whole group. The sequence and parameters are then applied in processing the whole data. In this paper, optimum processing sequence and parameters for the data acquired in Korean continental shelf are examined through test processing with real data. Finally, a good-quality migration section is produced using those sequence and parameters decided on the basis of the test results.

• Ocean and Polar Research
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• v.35 no.3
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• pp.239-247
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• 2013

Digital image processing is a process to analyze a large volume of information on digital images. In this study, Artemia hatching rate was measured by automatically classifying and counting cysts and larvae based on color imaging data from cyst hatching experiments using an image processing technique. The Artemia hatching rate estimation consists of a series of processes; a step to convert the scanned image data to a binary image data, a process to detect objects and to extract their shape information in the converted image data, an analysis step to choose an optimal discriminant function, and a step to recognize and classify the objects using the function. The function to classify Artemia cysts and larvae is optimally estimated based on the classification performance using the areas and the plan-form factors of the detected objects. The hatching rate using the image data obtained under the different experimental conditions was estimated in the range of 34-48%. It was shown that the maximum difference is about 19.7% and the average root-mean squared difference is about 10.9% as the difference between the results using an automatic counting (this study) and a manual counting were compared. This technique can be applied to biological specimen analysis using similar imaging information.

• Smart Structures and Systems
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• v.14 no.6
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• pp.1131-1150
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• 2014

One of the issues in extending the range of applicable problems of real-time hybrid simulation is the computation speed of the simulator when large-scale computational models with a large number of DOF are used. In this study, functionality of real-time dynamic simulation of MDOF systems is achieved by creating a logic circuit that performs the step-by-step numerical time integration of the equations of motion of the system. The designed logic circuit can be implemented to an FPGA-based system; FPGA (Field Programmable Gate Array) allows large-scale parallel computing by implementing a number of arithmetic operators within the device. The operator splitting method is used as the numerical time integration scheme. The logic circuit consists of blocks of circuits that perform numerical arithmetic operations that appear in the integration scheme, including addition and multiplication of floating-point numbers, registers to store the intermediate data, and data busses connecting these elements to transmit various information including the floating-point numerical data among them. Case study on several types of linear and nonlinear MDOF system models shows that use of resource sharing in logic synthesis is crucial for effective application of FPGA to real-time dynamic simulation of structural response with time step interval of 1 ms.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.11 s.188
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• pp.58-67
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• 2006

Due to the variety of signal processing and complicated mathematical analysis, it is not easy to accomplish 3D bin-picking with non-contact sensor. To solve this difficulties the reliable signal processing algorithm and a good sensing device has been recommended. In this research, 3D laser scanner and CCD camera is applied as a sensing device respectively. With these sensor we develop a two-step bin-picking method and reliable algorithm for the recognition of 3D bin object. In the proposed bin-picking, the problem is reduced to 2D intial recognition with CCD camera at first, and then 3D pose detection with a laser scanner. To get a good movement in the robot base frame, the hand eye calibration between robot's end effector and sensing device should be also carried out. In this paper, we examine auto-calibration technique in the sensor calibration step. A new thinning algorithm and constrained hough transform is also studied for the robustness in the real environment usage. From the experimental results, we could see the robust bin-picking operation under the non-aligned 3D hole object.

• Journal of the Ergonomics Society of Korea
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• v.16 no.3
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• pp.1-10
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• 1997

This paper is concerned with the development and evaluation of the camera calibration method for a real-time head tracking system. Tracking of head movements is important in the design of an eye-controlled human/computer interface and the area of virtual environment. We proposed a video-based head tracking system. A camera was mounted on the subject's head and it took the front view containing eight 3-dimensional reference points(passive retr0-reflecting markers) fixed at the known position(computer monitor). The reference points were captured by image processing board. These points were used to calculate the position (3-dimensional) and orientation of the camera. A suitable camera calibration method for providing accurate extrinsic camera parameters was proposed. The method has three steps. In the first step, the image center was calibrated using the method of varying focal length. In the second step, the focal length and the scale factor were calibrated from the Direct Linear Transformation (DLT) matrix obtained from the known position and orientation of the camera. In the third step, the position and orientation of the camera was calculated from the DLT matrix, using the calibrated intrinsic camera parameters. Experimental results showed that the average error of camera positions (3- dimensional) is about $0.53^{\circ}C$, the angular errors of camera orientations are less than $0.55^{\circ}C$and the data aquisition rate is about 10Hz. The results of this study can be applied to the tracking of head movements related to the eye-controlled human/computer interface and the virtual environment.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1629-1638
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• 2016

Differential power processing (DPP) systems are among the most effective architectures for photovoltaic (PV) power systems because they are highly efficient as a result of their distributed local maximum power point tracking ability, which allows the fractional processing of the total generated power. However, DPP systems require a high-efficiency, high step-up/down bidirectional converter with broad operating ranges and galvanic isolation. This study proposes a single, magnetic, high-efficiency, high step-up/down bidirectional DC-DC converter. The proposed converter is composed of a bidirectional flyback and a bidirectional isolated switched-capacitor cell, which are competitively cheap. The output terminals of the flyback converter and switched-capacitor cell are connected in series to obtain the voltage step-up. In the reverse power flow, the converter reciprocally operates with high efficiency across a broad operating range because it uses hard switching instead of soft switching. The proposed topology achieves a genuine on-off interleaved energy transfer at the transformer core and windings, thus providing an excellent utilization ratio. The dynamic characteristics of the converter are analyzed for the controller design. Finally, a 240 W hardware prototype is constructed to demonstrate the operation of the bidirectional converter under a current feedback control loop. To improve the efficiency of a PV system, the maximum power point tracking method is applied to the proposed converter.

• Journal of the Institute of Convergence Signal Processing
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• v.5 no.1
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• pp.6-12
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• 2004

Identification rate and time are very important in the identification of RFID tag, and the tag requires simple structure to use economically large quantity of tags. These factors make the MAC protocols of wired or wireless network environment result in different requirements. In the paper, we propose a method to apply spread spectrum scheme using orthogonal channel via Walsh function as the anti-collision communication system for the purpose of non-collision identification of multiple tags, and consider its property. The proposed system use two step identification. in the first step, collision is resolved via constructing to respond after specific delay time based on unique n, and conventional polling scheme follows in the second step.

• The KIPS Transactions:PartB
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• v.11B no.5
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• pp.611-618
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• 2004

This paper addresses the design and implementation of class distribution in distributed object-oriented databases. The proposed strategy of distribution consists of two-step design of fragments. One is class fragmentation and the other is allocation of fragments. In step of class fragmentation, we have defined partitioning algorithms to reflect the characteristics of object-oriented databases such as method, inheritance and composite-object. In step of allocation, we have defined the objective function for allocation considering system operating cost including storage, query processing and communication and implemented it using Genetic Algorithm.

• Journal of Astronomy and Space Sciences
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• v.2 no.1
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• pp.1-6
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• 1985

The U.S. Space Shuttle represents the beginning of a new era in transportation and is the critical element in the industrialization of the near-Earth-space. Most of its flights are dedicated to reducing costs launching commercial satellites. However, it provides a microgravity environment for processing unique and improved materials which is generating great interest in both civilian and military sectors. The space shuttle is also the necessary step in establishing a permanent space station which could host materials analysis laboratories and commercial processing facilities. This paper reviews the different elements of the space shuttle transportation system, a typical mission scenario, and discusses current activities in materials processing in space.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2010.04a
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• pp.181-182
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• 2010

For real-time displacement monitoring of large-scale structures, the high-rate (>1 Hz) GPS data processing is necessary, which is not possible even for the scientific GPS data processing softwares. Since the baseline is generally very short in this case, most of the atmospheric effects are removed, resulting in the unknowns of position and integer ambiguity. The number of unknowns in real-time kinematic GPS positioning makes the positioning impossible with usual approach, thus two-step approach is tested in this study.