• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.4
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• pp.357-367
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• 2008

Preparing for future Korean Lunar missions, preliminary Lunar mission design software is developed using a impulsive thrusting method. Developed software is capable of design and analysis every required mission phases to design Lunar mission, including the Earth departure, Lunar transfer, Lunar arrival and mission operation phases. Also, assuming that KSLV-II is selected as a launch vehicle, future Korean Lunar explorer's mass budget is estimated based on driven optimal trajectory characteristics. Tracking analysis is also performed using Deep Space Network including angle geometry analysis between Earth - Moon - Lunar explorer - Sun which are very important for communication, solar panel pointing strategy and eclipse analysis when Lunar missions are under designing phase.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.5
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• pp.552-559
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• 2008

Three dimensional numerical analysis were performed to investigate the combustion characteristics in a tangentially fired pulverized coal boiler. The predicted values at the outlet of economizer for the gas temperature, O$_2$, NO, CO were been compared with the measured data. By using the actual operating conditions of the power plant, the distribution of velocity, gas temperature, O$_2$, CO, CO$_2$ and NO as well as the particle tracking in the boiler were investigated. Throughout the present study, the non-uniform distribution of flue gas temperature in front of the final superheater might be resulted from the residual swirl flow in the upper furnace of the boiler. The present analysis on non-uniform distribution of the gas temperature could provide the useful information to prevent the frequent tube failure from happening in the final superheater of the tangentially coal-fired boiler.

• Journal of the Korean association of regional geographers
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• v.17 no.1
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• pp.75-95
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• 2011

A birth cohort approach to the Household life-cycle model could be an alternative to cross-sectional data. In this study, each residential mobilities of birth cohorts' is traced by the cohort data from repeated cross-section in the case of Jinju city. Because of the differences in fertilities by era, the volume of each cohort as a consumer in housing has varied and the condition of housing stock also has changed as the time goes by. These changes in housing make not only age effect stressed in Rossi's model, but also cohort and period effect. Due to theses effects of time, every residential mobility trajectories of generations' is different especially in earlier life stages. As households get older, it is found that the age effect reduces and the probability of residential mobility is lower. As this result, the residential succession and filtering between the earlier and latter generations is weakened and the residential segregation could be happened by birth cohort.

• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.95-100
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• 1995

In this study, we have evaluated the effect of amplitude and frequency perturbation of EGG signal for single vowels associated with laryngeal pathology. The normal EGG signal was properly characterized by an autoregressive model which has an optimal order of ninth using the parametric method. This can be analyzed by determining the transfer function. Perturbations in the fundamental pitch and in the peak amplitude of EGG signal measured with a four-electrode system using the modulation/demodulation techniques were investigated for the purpose of developing a decision criteria for the laryngeal function analysis. The abnormal EGG signal has nonperiodic and unstable characteristics. It can be discriminated by the calculation of opening and closing time of glottis using the EGG signal. In case of normal and abnormal subjects, m$\pm$0.5*sd was discriminating line for frequency perturbation and m$\pm$2*sd for normal amplitude perturbations, respectively. Also, The normal and abnormal cases of the subjects can be discriminated effectively using the pattern of attractor derived with Hilbert transform of EGG signal.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.112-122
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• 1995

We assume that the KOREASAT fails the entry of the geostationary orbit due to the error at the apogee kick motor firing. A simulation is done for the satellite that has a geosynochronous orbit with a non-zero degree inclination angle due to the failure at the apogee kick motor firing caused by the unbalance of the fuel storage and the spin of the thrust vector, etc. We analyzed the evolution of the orbit using the perturbation theory and calculated the changes of the eccentricity and the inclination. WHen a communication satellite has the figure eight trajectory, the beam point also traces the satellite. In this paper, We develope an algorithm to attack the above problem by stabilizing the beam point using the adjustment of the roll angle of the satellite. The spin action on the polarization plane that occurs when a satellite passes the ascending node and descending node affects the efficiency of the communication a lot, so we did another simulation for the better yaw angle adjustment for the KOREASAT to reduce the spin actino on the polarization plane.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.49-57
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• 2004

In This paper the embedded linux based embedded control system was used and the tracking antenna system was studied for data link and communication between moving vehicles. A microprocessor based embedded controller is equipped with SA-1110 board and this embedded controller can control the azimuth and the elevation angle of the antenna. The relative position and attitude for pointing are calculated by using the GPS position signals from the moving vehicle. To verify the performance of the designed embedded antenna system, the orbit information of the Arirang satellite(from KARI) is used.

• Journal of Korea Multimedia Society
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• v.9 no.4
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• pp.451-459
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• 2006

Color reproduction of small LCD display is quite different from that of standard CRT due to the difference of physical, electrical, and optical characteristics. In this paper, we propose a simple and practical method using gamma and CCT correction for improvement of color reproduction on a small LCD display. First, we investigate characteristics of a small LCD display such as brightness, uniformity, color temperature, white and black balance, and nonlinear gamma. And, we also analyze color reproduction region and CCT trajectory according to LCD's input levels. Finally, the optimum gamma and CCT compensation method using LUT is proposed, and our proposed method was realized at mobile phone without hardware modification. In the experimental results, the result image of proposed algorithm is more close to standard color.

• The KIPS Transactions:PartB
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• v.16B no.5
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• pp.347-358
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• 2009

In this thesis, we develop a vision based hand motion recognition system using a camera with two rotational motors. Existing systems were implemented using a range camera or multiple cameras and have a limited working area. In contrast, we use an uncalibrated camera and get more wide working area by pan-tilt motion. Given an image sequence provided by the pan-tilt camera, color and pattern information are integrated into a tracking system in order to find the 2D position and direction of the hand. With these pose information, we estimate 3D motion plane on which the gesture motion trajectory from approximately forms. The 3D trajectory of the moving finger tip is projected into the motion plane, so that the resolving power of the linear gesture patterns is enhanced. We have tested the proposed approach in terms of the accuracy of trace angle and the dimension of the working volume.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.4
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• pp.521-526
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• 2012

The performance of arrow from a manufacturing process depends on arrow's trajectory(archer's paradox) and intensity of an impact points. Especially, when conducting a shooting experiment over and over in the same experiment condition, the intensity of impact point is an objective standard to judge the performance of the arrow. However, the analysis method for the impact point is not enough, a previous research of the arrow's performance has been focused on a skill to optimize a manufacturing variables(feathers of an arrow, barb of an arrow, arrow's shaft, weight, external diameter, spine). In this paper, We propose measurement system of arrow's impact point with Mamdani fuzzy inference system and similarity of polygon for automation of impact point's measurement. Measuring the impact point data of the arrow moving with a high speed(approximately 275km/h) by using line laser and photo diode array, then the measured data are mapped to arrow's impact point with fuzzy inference and similarity of polygon.

• Journal of Navigation and Port Research
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• v.28 no.3
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• pp.259-268
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• 2004

For the last years, it has become hot issue such as disposal of the treated wastewater, which caused by increment of a population and industrial development at the coastal areas. The ocean outfall system discharges primary or secondary treated effluent into coastline or at the deep water, or between these two. The effluent, which has a density similar to that of fresh water, rises to the see, surface forming plume or jet, together with entraining the surrounding salt water and becomes very dilute. This paper deals ocean outfall design which effects to decision-making about marine environment management and wastewater treatment. In order to make predictions of dilution of discharged water and the trajectory of a plume, CORMIX has been used considering several elements including a seasonal and tidal changes. These solutions are strung together to provide basic data and general drawings for effective management of outfall.