• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 ITC-CSCC -1
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• pp.454-457
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• 2000

In this paper, an efficient rate control algorithm based on rate prediction is proposed for maintaining a smooth buffer variation and a small buffer size. The proposed method adjusts the quantization scaling factor by using the predicted bit-rate to meet the target bit budget exactly. Experimental result show that the proposed prediction-based rate control scheme can regulate the bit-rate across scene changes more effectively and achieve better PSNR performance than existing rate control mechanisms such as the MPEG-2 Test Model 5 (TM5) and the Adaptive Scene Analysis (ASA).

• 제어로봇시스템학회논문지
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• 제22권7호
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• pp.536-542
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• 2016

To enhance tracking efficiency, a target-tracking filter with a resource management algorithm is required. One of the resource management algorithms chooses or evaluates the proper sampling time using cost functions which are related to the target tracking filter. We propose a resource management algorithm for bearing only tracking environments. Since the tracking performance depends on the system observability, the bearing-only tracking is one of challenging target-tracking fields. The proposed algorithm provides the adaptive sampling time using the variation rate of the error covariance matrix from the target-tracking filter. The simulation verifies the efficiency performance of the proposed algorithm.

• 음성과학
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• 제9권4호
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• pp.15-25
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• 2002

It's not easy to produce very high tones during singing for not only untrained ordinary people but also even trained singers. To get high singing tones from the low tones, some trained singers used to use a distinguished singing technique, Passaggio (vocal register transition). The purpose of this study is to compare several voice parameters variation between when to sing with using the passaggio technique and to sing without using it. We selected 18 male singers (tenor 8, baritone 10), who had more than 7 years of experience and were well trained in passaggio technique. Simultaneous measurements of fundamental frequency (F0), mean flow rate (MFR), intensity (I), and subglottal pressure (Psub) were performed using the phonatory function analyzer (Nagashima). For the tenor, target tones /a/ were presented: 1) easy phonation: $B_{2}$, 2) high tone without passaggio: F$#_{3}$ 3) high tone with passaggio: F$#_{3}$. For the baritone, target tones /a/ were presented: 1) easy phonation: G$#_{3}$, 2) high tone without passaggio: D$#_{3}$, 3) high tone with passaggio: D$#_{3}$. F0 of the target tones between non-passaggio group and passaggio group was almost the same in both tenor and baritone groups. Intensity of the non-passaggio and passaggio vocalization was much louder than that of easy phonation and pasaggio was louder than non-passaggio vocalization (especially statistically significant in baritone singers). MFR of the passaggio vocalization was greater than non-passaggio vocalization in both tenor and baritone group, but statistically significant only in baritone. Psub of the passaggio vocalization was greater than that of the non-passaggio vocalization in both tenor and baritone group, but statistically not significant in tenor.

• 말소리와 음성과학
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• 제7권3호
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• pp.139-149
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• 2015

This paper aims to analyze pronunciation variations of loanwords produced by Korean and improve the performance of pronunciation modeling of loanwords in Korean by using syllable-based segmentation and phonological knowledge. The loanword text corpus used for our experiment consists of 14.5k words extracted from the frequently used words in set-top box, music, and point-of-interest (POI) domains. At first, pronunciations of loanwords in Korean are obtained by manual transcriptions, which are used as target pronunciations. The target pronunciations are compared with the standard pronunciation using confusion matrices for analysis of pronunciation variation patterns of loanwords. Based on the confusion matrices, three salient pronunciation variations of loanwords are identified such as tensification of fricative [s] and derounding of rounded vowel [ɥi] and [$w{\varepsilon}$]. In addition, a syllable-based segmentation method considering phonological knowledge is proposed for loanword pronunciation modeling. Performance of the baseline and the proposed method is measured using phone error rate (PER)/word error rate (WER) and F-score at various context spans. Experimental results show that the proposed method outperforms the baseline. We also observe that performance degrades when training and test sets come from different domains, which implies that loanword pronunciations are influenced by data domains. It is noteworthy that pronunciation modeling for loanwords is enhanced by reflecting phonological knowledge. The loanword pronunciation modeling in Korean proposed in this paper can be used for automatic speech recognition of application interface such as navigation systems and set-top boxes and for computer-assisted pronunciation training for Korean learners of English.

• 대한방사선치료학회지
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• 제29권2호
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• pp.53-64
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• 2017

목 적: 표적의 길이가 긴(length) 환자의 용적회전변조 방사선치료(V-MAT) 시 회전방향 오차의 크기에 따른 선량차이 경향을 $HexaPOD^{TM}$ evo RT system(6DoF couch)을 통해 알아보고 그 유용성을 평가하고자 하며, 이에 따른 회전오차 보정의 필요성을 제안하고자 한다. 대상 및 방법: 본원에서 치료를 받은 Esophagus cancer와 SCL을 포함한 Breast cancer 환자 중 HexaPOD 6DoF(Six-Degree of Freedom) couch를 사용한 10명을 대상으로 하였다. 6DoF couch를 이용하여 Rx(pitch), Ry(roll), Rz(yaw) 방향의 회전오차의 적용여부에 따른 선량차이를 알아보기 위하여 x, y, z축에 대한 자세오차를 확인하고, 자세 회전오차 값을 6DoF couch에 부여 임의의 오차를 발생시켜 변형된 선량계측 품질보증(Delivery Quality Assurance, DQA)을 시행, 점 선량과 감마값을 비교 분석하였다. 추가적으로 3cm의 직경에 5, 10, 15, 20 cm의 길이를 가진 각각의 표적의 치료계획에 회전오차의 크기를 $1^{\circ}$ 간격으로 적용한 후, 표적의 길이와 회전오차의 종류 및 크기에 따른 감마통과율의 변화양상을 확인했다. 결 과: 자세 회전오차가 적용된 경우의 점 선량과 감마통과율의 평균오차는 각각 Rx 방향에서 $2.50{\pm}1.11%$, $84.1{\pm}7.39%$, Ry 방향에서 $2.36{\pm}1.16%$, $81.0{\pm}8.49%$, Rz 방향에서 $2.35{\pm}1.10%$, $84.4{\pm}6.99%$를 나타냈다. 또한, 표적의 길이와 회전오차의 종류 및 크기에 따른 감마통과율 분석 결과 Ry 방향을 제외한 Rx와 Rz 방향에서 회전오차가 커질수록 감마통과율은 전반적으로 감소하는 경향을 보였으며, 특히 10 cm의 표적, Rz 방향으로 $2.5^{\circ}$ 회전오차가 부여된 경우에서 가장 낮은 감마통과율인 74.2 %를 나타냈다. 결 론: 표적의 길이가 긴 치료부위의 용적회전변조 방사선치료 시 회전오차의 보정은 필요하며, 6DoF couch의 사용은 환자자세의 재현성과 치료의 질적 효율을 높일 것으로 사료된다.

• 한국작물학회지
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• 제50권4호
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• pp.238-246
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• 2005

Rice yield and protein content have been shown to be highly variable across paddy fields. In order to characterize this spatial variability of rice within a field, two-year experiments were conducted in 2002 and 2003 in a large-scale rice field of $6,600m^2$ In year 2004, an experiment was conducted to know if variable rate treatment (VRT) of N fertilizer, that was prescribed for site-specific management at panicle initiation stage, could reduce spatial variation in yield and protein content of rice while increasing yield compared to conventional uniform N topdressing (UN, 33kg N/ha at PIS) method. VRT nitrogen prescription for each grid was calculated based on the nitrogen (N) uptake (from panicle initiation to harvest) required for target rice protein content of $6.8\%$, natural soil N supply, and recovery of top-dressed N fertilizer. The required N uptake for target rice protein content was calculated from the equations to predict rice yield and protein content from plant growth parameters at panicle initiation stage (PIS) and N uptake from PIS to harvest. This model· equations were developed from the data obtained from the previous two-year experiments. The plant growth parameters for the calculation of the required N were predicted non-destructively by canopy reflectance measurement. Soil N supply for each grid was obtained from the experiment of year 2003, and N recovery was assumed to be $60\%$ according to the previous reports. The prescribed VRT N ranged from 0 to 110kg N/ha with an average of 57kg/ha that was higher than 33 kg/ha of UN. The results showed that VRT application successfully worked not only to reduce spatial variability of rice yield and protein content but also to increase rough rice yield by 960kg/ha. The coefficient of variation (CV) for rice yield and protein content was reduced significantly to $8.1\%$ and $7.1\%$ in VRT from $14.6\%$ and $13.0\%$ in UN, respectively. And also the average protein content of milled rice in VRT showed very similar value of target protein content of $6.8\%$. In conclusion the procedure used in this paper was believed to be reliable and promising method for reducing within-field spatial variability of rice yield and protein content. However, inexpensive, reliable, and fast estimation methods of natural N supply and plant growth and nutrition status should be prepared before this method could be practically used for site-specific crop management in large-scale rice field.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제14권2호
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• pp.221-225
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• 2008

센서네트워크에서 목표물 탐지하는데 있어 높은 샘플링이 수반되어야 하는 주파수 분석을 피하기 위하여, 낮은 샘플링 데이타를 이용하더라도 목표물 식별이 가능한 시계열(Time-series) 분석 기법으로서 시간 정합 유사도 측정 알고리즘을 소개하고 그 중에 가장 우수한 DTW-Cosine 알고리즘을 제안한다. 시계열 분석 기법을 이용하여 패턴을 비교하기 위해서는 지역 시간 이동 문제와 공간 신호 변이 문제를 극복해야 하는데 DTW-Cosine 알고리즘은 이를 효과적으로 극복함과 동시에 Smoothing 기법을 통하여 다른 시간 정합 유사도 측정 알고리즘들에 비해 전체적으로 최소 10.31% 이상의 우수한 성능을 보였다.

• 한국의학물리학회지:의학물리
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• 제28권4호
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• pp.181-189
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• 2017

The conventional delivery quality assurance (DQA) process for RapidArc (Varian Medical Systems, Palo Alto, USA), has the limitation that it measures and analyzes the dose in a phantom material and cannot analyze the dosimetric changes under the motional organ condition. In this study, a DQA method was designed to overcome the limitations of the conventional DQA process for internal target volume (ITV) based RapidArc. The dynamic DQA measurement device was designed with a moving phantom that can simulate variable target motions. The dose distribution in the real volume of the target and organ-at-risk (OAR)s were reconstructed using 3DVH with the ArcCHECK (SunNuclear, Melbourne, USA) measurement data under the dynamic condition. A total of 10 ITV-based RapidArc plans for liver-cancer patients were analyzed with the designed dynamic DQA process. The average pass rate of gamma evaluation was $81.55{\pm}9.48%$ when the DQA dose was measured in the respiratory moving condition of the patient. Appropriate method was applied to correct the effect of moving phantom structures in the dose calculation, and DVH data of the real volume of target and OARs were created with the recalculated dose by the 3DVH program. We confirmed the valid dose coverage of a real target volume in the ITV-based RapidArc. The variable difference of the DVH of the OARs showed that dose variation can occur differently according to the location, shape, size and motion range of the target. The DQA process devised in this study can effectively evaluate the DVH of the real volume of the target and OARs in a respiratory moving condition in addition to the simple verification of the accuracy of the treatment machine. This can be helpful to predict the prognosis of treatment by the accurate dose analysis in the real target and OARs.

• 말소리와 음성과학
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• 제10권1호
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• pp.23-31
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• 2018

In this study, we examined how the upper and lower lips articulate to produce labial /p/. Using electromagnetic midsagittal articulography, we collected flesh-point tracking movement data from eight native speakers of Seoul Korean (five females and three males). Individual articulatory movements in /p/ were examined in terms of minimum vertical upper lip position, maximum vertical lower lip position, and corresponding vertical upper lip position aligned with maximum vertical lower lip position. Using linear mixed-effect models, we tested two factors (word boundary [across-word vs. within-word] and speech rate [comfortable vs. fast]) and their interaction, considering subjects as random effects. The results are summarized as follows. First, maximum lower lip position varied with different word boundaries and speech rates, but no interaction was detected. In particular, maximum lower lip position was lower (e.g., less constricted or more reduced) in fast rate condition and across-word boundary condition. Second, minimum lower lip position, as well as lower lip position, measured at the time of maximum lower lip position only varied with different word boundaries, showing that they were consistently lower in across-word condition. We provide further empirical evidence of lower lip movement sensitive to both different word boundaries (e.g., linguistic factor) and speech rates (e.g., paralinguistic factor); this supports the traditional idea that the lower lip is an actively moving articulator. The sensitivity of upper lip movement is also observed with different word boundaries; this counters the traditional idea that the upper lip is the target area, which presupposes immobility. Taken together, the lip aperture gesture is a good indicator that takes into account upper and lower lip vertical movements, compared to the traditional approach that distinguishes a movable articulator from target place. Respective of different speech rates, the results of the present study patterned with cross-linguistic lenition-related allophonic variation, which is known to be more sensitive to fast rate.

• 한국실내디자인학회논문집
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• 제27권3호
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• pp.136-144
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• 2018

The purpose of this study is to examined the unconscious response of the pupil in the observation toward the image in the eye-tracking experiments that target on a large complex cultural space. Twenty-five men participated in this experiment and the observation data were analyzed in seconds per minute on watching time. It could examine the unconscious response of information searching in the change of pupil size in the process of observing the space. The results could be defined as following several points. First, it was possible to outline the unconscious response characteristics of pupil by analyzing sudden changes in pupil size as total, cumulative, and individual. The response characteristics using frequency and time can be utilized as the analytical method to examine the degree of interest of spatial components according to the purpose of analysis in the future. Second, according to the over ${\pm}5%$ of cumulative variation rate on the pupil size change, during in the 60 seconds, the continuous pupil dilation was used 25.2 seconds in 8.8 rounds and the pupil reduction was used 18.0 seconds in 7.0 rounds. Third, when the variation rate of ${\pm}5%$ or more was regarded as the sudden changes on pupil size by individual variation, the pupil dilation was 7.2 rounds of 8.6 seconds and pupil reduction was 6.0 seconds in 5.0 rounds. This means that the pupil increases 9.3% in one expansion and decreases -8.5% in the reduction process. As regarding pupil changes as cumulative rate, it appeared high change rate on pupil reduction but it became higher on pupil dilation in individual.