• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.8
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• pp.692-698
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• 2015

This paper represents a trajectory design and analysis technique which uses invariant manifolds of the circular restricted three body problem. Instead of the classical patched conic method based on 2-body problem, the equation of motion and dynamical behavior of spacecraft in the circular restricted 3-body problem are introduced, and the characteristics of Lyapunov orbits near libration points and their invariant manifolds are covered in this paper. The trajectories from/to Lyapunov orbits are numerically generated with invariant manifolds in the Earth-moon system. The trajectories in the Sun-Jupiter system are also analyzed with various initial conditions in the boundary surface. These methods can be effectively applied to interplanetary trajectory designs.

• Microbiology and Biotechnology Letters
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• v.38 no.4
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• pp.455-460
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• 2010

A polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis was applied to detect and identify ten Weissella spp. frequently found in kimchi. The previously reported genus-specific primers designed from 16S rDNA sequences of Weissella spp. were adopted but PCR was performed at the increased annealing temperature by $4^{\circ}C$. The sizes of amplified PCR products and restricted fragments produced by AluI, MseI, and BceAI endonucleases were well correspond with the expected sizes. W. kandleri, W. koreensis, W. confusa, W. minor, W. viridescens, W. cibaria, and W. soli were distinguished by AluI and MseI and W. hellenica and W. paramesenteroides were identified by BceAI. W. thailandensis was distinguished when restriction pattern of other species was compared but identified by the single use of MspI.

• Journal of the Society of Naval Architects of Korea
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• v.37 no.3
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• pp.21-26
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• 2000

For coastal service ships, the water depth is a very important parameter in the design stage of the hull form that has an influence on the restriction of the speed and draft of ships. In this study, the water depth is important for ship design. In this research, the change of total resistance, trim and sinkage due to the variation of water depth are measured by using on equipment for shallow water condition. For the basic research step about the shallow water effect, the effects on Series60($C_B=0.6$) hull form are experimented. To compare with existing experiment results, the test conditions are same with those. The water depth conditions are 10, 15, 20, 25% of LPP of the model ship, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.26 no.2
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• pp.179-188
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• 2015

Testing a radar system in real environment requires a lot of time and cost. Thus various target simulators are developed to evaluate the radar performance and its functions as well. In order to enhance the range resolution and the accuracy for tracking, recent radar system tends to use the wideband signal. In this paper, we summarize two target simulation methods - the direct sampling method with the digital memories and the beat frequency generation for the stretch processing - and suggest the condition to improve their performance for a wideband radar system.

• Journal of Sensor Science and Technology
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• v.8 no.1
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• pp.80-88
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• 1999

This paper deals with the position determination problem of stereo camera systems used as a sensor for 3D robotic manipulation. Stereo cameras having parallel rays of sight and been set up on the same baseline are assumed. The distance between the sensor and the space measured is determined so as to get insensitive parameters to the uncertainty of control points used for calibration and to satisfy the error condition set by considering the repeatability of the robot. The baseline width is determined by minimizing the mutual effect of 3D positional error and stereo image coordinate error. Unlike existing techniques, the technique proposed here is developed without complicated constraints and modelling process of the object to be observed. Thus, the technique of this paper is more general and its effectiveness is proved by simulation.

• The Journal of Information Technology
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• v.7 no.2
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• pp.19-28
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• 2004

Many kind of operators using Residue Number System are used to design the special purpose processor for many merits in Digital Signal Processing, Computer Graphics, etc. But It get demerits for general division and the magnitude comparison. In this paper, general division operator for divisor with a small number in RNS is proposed. If the result of division using the multiplicative inverse has remainder, the quotient of this is larger than maximum quotient of division that has the same divisor to dividend of the maximum size. This condition is used for the ending condition of the recursive operation. And, the divisor is substitute for the compared value of quotients. So, the proposed division operator has a small size and fine operation speed, but with the limitation of divisor.

• The Transactions of the Korea Information Processing Society
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• v.4 no.12
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• pp.3200-3210
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• 1997

In image processing we encounter some tasks to detect ellipse or to discriminate the curves. LSM is well used to fit curves to ellipse but it can fail to fit correctly when fitting to defected one. To overcome this problem, we propose Modified LSM. Only 2-parameters among 5-paramaters are to be determined by LSM, while 3-parameters are to be calculated by the constrain that the curve must pass 3 given points. Those 3 points are selected by operator so as to have elliptic feature. Such proposed MLSM shows better result than genunal LSM in case when the ellipse is severely defected. and is proved to be good method for determing the human dentition.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.5
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• pp.549-560
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• 1989

In this paper, the method of determining the initial weighting vlaues fuctioning as a filter under the Directional Constrained Minimization of Power(DCMP) algorithm is presented. By analyzing the sideband beamformer with the Finite Impulse Response (FIR) filter concepts, the constraints of any desired directions are obtained and the initial weighing values with fast adaptation time are formulated from those constraints. By applying this proposed initial weighting values to the DCMP and the spatial averaging processor, the interference of a desired direction and the coherent noises are eliminated at the same time. The improvement of this method compared with the existing algorithm is confirmed by computer simulation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.4
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• pp.685-690
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• 1994

A problem associated with vector quantization(VQ) is the computational complexity incurred in searching for a codevector with the closet to a given input vector, where the complexity increases exponentionally with proportion to codebook size and then limits practical application. In this paper, a simple and fast, but efficient, VQ encoding algorithm is presented using a reference codevector as start codevector of premature exit condition, which eliminates distance claculation of unlikely codevectors. The algorithm is to find reference codevector having the possibility to be the nearest vector to input vector first and then to incorporate premature exit condition. The proposed algorithm needs only 10~15% of mathematical operations compared with the conventional full search VQ. Algorithm the number of additions and comparsions of the proposed algorithm is not reduced greatly, the number of multiplication is reduced up to 70~80% compared with other fast VQ encoding methods.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.1
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• pp.27-36
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• 2001

Recently, the coastal transportation of the Yellow Sea is increasing due to the vastly expanding trade among countries surrounding the Yellow Sea. As the 50 percentages of the total domestic container transportation are concentrated on the National Capital region, the traffic congestion in the key land transportation routes brings about the weakening of the global competitiveness. In this study, the efficient barge systems for sea-river shipping of the Han-river, the Kyongin canal and coastal ways of the Yellow Sea are considered based on the criterion of canal and cargo volumes. To find the efficient barge system of the model barge in the Kyongin canal. the transport efficiency factor and transport ability of each barge system with the variation of sailing speed and length are calculated.