• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1113-1116
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• 1999

In this papers, we proposes a efficient compression method of an image using the extraction of boundary region of DCT in MPEG-1. DCT coefficients have from low frequency to high frequency various components. After performing DCT to an image, the data is compressed to contain the boundary Region by quantization, and the information of boundary Region can be extracted by inverse DCT. In those, I chose frequency components susceptible to the boundary through the many experiences. In this paper, boundary can be selected by dividing low frequency by big quantization coefficient and dividing high frequency by small quantization coefficient without degrading visual qualify in MPEG-1. Also it is predicted that to reduce high frequency value will be good in noisy environments.

• 센서학회지
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• 제24권4호
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• pp.247-251
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• 2015

In this study, electroglottographic spectral tilt (EST) was investigated for characterization of vocal cords vibration. EST was analyzed from the power spectrum of electroglottographic signals by dividing frequency analysis range as full range (0~4 octave), low range (0~2 octave), and high range (2~4 octave). EST of all ranges in female were greater than those in male. In female and male groups, EST of high range was higher than that of low range. This result suggests that EST has at least two components and dividing frequency range in analysis of EST is effective for investigating characteristics of vocal cords vibration.

• 전자공학회논문지S
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• 제34S권4호
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• pp.57-65
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• 1997

The purpose of this paper is to propose the HMM (hidden markov model) based on multi-observation sequence for the isolated word recognition. The proosed model generates the codebook of MSVQ by dividing each word into several sections followed by dividing training data into several sections. Then, we are to obtain the sequential value of multi-observation per each section by weighting the vectors of distance form lower values to higher ones. Thereafter, this the sequential with high probability value while in recognition. 146 DDD area names are selected as the vocabularies for the target recognition, and 10LPC cepstrum coefficients are used as the feature parameters. Besides the speech recognition experiments by way of the proposed model, for the comparison with it, the experiments by DP, MSVQ, and genral HMM are made with the same data under the same condition. The experiment results have shown that HMM based on multi-observation sequence proposed in this paper is proved superior to any other methods such as the ones using DP, MSVQ and general HMM models in recognition rate and time.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 1999년도 추계 학술대회논문집
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• pp.85-94
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• 1999

Transient aerodynamic response of an airfoil to a moving plane-flap is numerically investigated using two-dimensional Euler equations with conservative Chimera grid method. A body moving relative to a stationary grid is treated by an overset grid bounded by a 'dynamic domain-dividing line' the concept of which is developed in this study. A conservative Chimera grid method with a dynamic domain-dividing line technique is applied and validated by solving the flowfield around circular cylinder moving supersonic speed. The unsteady and transient characteristics of the flow solver is also examined by computations of a oscillating airfoil and a ramp pitching airfoil respectively. The transient aerodynamic behavior of an airfoil with a moving plane-flap is analyzed for various flow conditions such as deflecting rate of flap and free stream Mach number.

• 대한기계학회논문집A
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• 제27권11호
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• pp.1917-1924
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• 2003

This paper proposes a roughing path generation method fer machining impeller with 5-axis machining center. Traditional researches are focus on finishing for machining impeller. To achieve efficient machining, roughing method must be studied. The proposed method consists two steps : One is to select optimal tool size and tool attitude by dividing cutting area into two regions to reduce cutting time. The regions are automatically divided by character point on the geometry of impeller blade. After dividing, the tool of the optimal size is selected for each divided region. The other is avoidance of tool interference. Tool interference in cutting areas is avoided by checking the distance between tool axis vector and ruling line on blade surface or approximated plan between ruling line. Using this method, the cutting time is reduced efficiently.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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• pp.284-287
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• 1996

In this paper, we investigated the optical coupling characteristics for $K^{+}$ ion-exchanged diffused channel waveguide by using coupled-mode equations. In this case, the optical-power-dividing was observed at the waveguide-type optical coupler with 3[$\mu\textrm{m}$] line-width and, 6[$\mu\textrm{m}$] separation between channel waveguides in which interaction lengths were 1 and 3[mm], respectively, On the basis of that we deformed simulation for $Ag^{+}$ ion-exchanged diffused channel waveguide. As a result of simulation, the optical-power-dividing was shown at the waveguide-type optical coupler wish 3[$\mu\textrm{m}$] line-width, 6[$\mu\textrm{m}$] separation between channel waveguides and 0.11[mm] interaction length.

• 대한약침학회지
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• 제4권1호
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• pp.49-53
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• 2001

This experiment has investigated the influence of Yamen (Du. 15) point injection on learning and memory dysfunction caused by cerebral ischemia and reprofusion in bilateral cervical general artery combined with bleeding on mouse tail to mimic vascular dementia in human beings. By dividing 40 mice into 4 groups (group1false operation group, group2model group, group3point injection with Cerebrolysin group4point injection with saline.) According to random dividing principles, we observed the influence of Yamen(Du. 15) point injection on the time of swimming the whole course used by model mice which had received treatment for different days in different groups, and the influence of those mice on wrong times they entered blind end. The result showed that point injection with Cerebrolysin and saline could improve learning and memory dysfunction of the mice caused by cerebral ischemia.

• 산업경영시스템학회지
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• 제6권8호
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• pp.81-91
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• 1983

In this study the methods of the overhead standard setting and the overhead variance analysis, which raise problems especially in business practice in case that small businesses introduce the standard cost accounting system, were examined by hypothetical examples. As the result of this study small businesses are advised to take the following in setting the overhead cost. (1) To divide the mixed cost into variable overhead and fixed overhead, it is desirable to take Beast square method. (2) In setting the overhead standard, it is desirable to fake the flexible budget system and to make a budget by the inspection method, after dividing the overhead into variable overhead and fixed overhead. (3) After dividing the overhead variance into variable overhead variance and fixed overhead variance, it is desirable to analyze them as follows. (A) Variable overhead variance is analyzed into spending variance and efficiency variance. (B) Fixed overhead valiance is analyzed into budget variance and denominator variance.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 C
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• pp.1523-1525
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• 1994

This paper describes a proposed very fast transient overvoltages(VFTO) measurement system suited for established gas insulated switchgear(GIS). The detecting system consists of a shield electrode connected to a buffer amplifier, and the transmission of the detected signal to an oscilloscope is made through an optical fiber. The bandwidth of the measurement system is 5 Hz to 30MHz. When determining the voltage dividing ratio by use of the commercial frequency voltage, the error is less than 0.5 %. Also, the data were obtained by the electric field probe and the high voltage probe, and their deviation for voltage dividing ratio were less than 1 %.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -3
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• pp.1630-1633
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• 2002

In this paper, we proposed a new control system of the dividing ratio changeable type ADPLL (DCPLL). The DCPLL has been designed by us. However, in the DCPLL, there are some problems such as this curcuit is increased the output jitter on multiple frequency, and the output jitter is large on steady state. Then, the output jitter characteristic on multiple frequency is improved by using “rest-control” system. Also, output jitter decreases by using “W-edge (positive edge h negative edge)” system. We confirmed some characteristics of the DCPLL with the circuit simulator, PSpice.