• 환경영향평가
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• 제7권2호
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• pp.83-88
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• 1998

Filter badge type sampler has not been widely used to evaluate air quality over large cities in Korea while it can be successfully used for multi-point sampling and analysis. We evaluated the passive sampler as a new tool to monitor air quality over large cities. We latticed Metropolitan Seoul into $2{\times}2Km$ to give 136 points. $NO_2$ concentrations were measured at all the points in the Spring and Summer of 1997. According to the passive sampler data, natural green zones generally recorded lower $NO_2$ concentrations than major streets and traffic congestion areas. Passive samplers with abundant 136 points gave more detailed picture of $NO_2$ distribution while auto-monitoring network did not clearly provide the characteristics of local land use. Also, passive samplers gave 15% higher values than auto-monitoring network. The correlation between the two values appears very high judging from the regression slope of 0.92 and correlation coefficient of 0.91. This study clearly demonstrates the effectiveness of the passive sampler as a tool to monitor air quality over large cities.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권9호
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• pp.1613-1631
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• 2011

Several metrics have been reported in the literature to assess stereo image quality, mostly based on visual attention or human visual sensitivity based distortion prediction with the help of disparity information, which do not consider the combined aspects of human visual processing. In this paper, visual attention and depth assisted stereo image quality assessment model (VAD-SIQAM) is devised that consists of three main components, i.e., stereo attention predictor (SAP), depth variation (DV), and stereo distortion predictor (SDP). Visual attention is modeled based on entropy and inverse contrast to detect regions or objects of interest/attention. Depth variation is fused into the attention probability to account for the amount of changed depth in distorted stereo images. Finally, the stereo distortion predictor is designed by integrating distortion probability, which is based on low-level human visual system (HVS), responses into actual attention probabilities. The results show that regions of attention are detected among the visually significant distortions in the stereo image pair. Drawbacks of human visual sensitivity based picture quality metrics are alleviated by integrating visual attention and depth information. We also show that positive correlation with ground-truth attention and depth maps are increased by up to 0.949 and 0.936 in terms of the Pearson and the Spearman correlation coefficients, respectively.

• 한국정보통신학회논문지
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• 제15권4호
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• pp.839-844
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• 2011

IPTV 콘텐츠는 MPEG2-TS(Moving Picture Expert Group-2 Transport Stream)에 기반을 두고 있으며, 생성된 콘텐츠는 인터넷 서비스망을 이용하여 각 가정의 수신기(Set-Top Box)에 전달되고, 이는 디코딩(Decoding) 과정을 거쳐 텔레비전에 보이게 된다. 하지만 기존의 제공된 회선 이외에 다른 장치에서의 콘텐츠 확대 이용 및 소비는 상당히 제한적 이었으며, 이를 위해 MPEG2-TS를 다른 포맷으로 변환 전송 등의 방법이 다양하게 제공되었으나 이들 방법들은, 시스템에 부하를 많이 가져올 뿐만 아니라, 자체적인 하드웨어 요구 사양이 높아지는 결과를 초래하였다. 이에 본 논문에서는 IPTV 내에서 MPEG2-TS로 제공되는 콘텐츠를 RTP(Real time Transport Protocol)를 이용하여 사용자에게 좀 더 다양한 장치와 환경에 적용 및 제공하는 시스템을 설계 및 구현하였다. 본 논문에서는 기존의 MPEG2-TS로 제공되는 다양한 콘텐츠에 대한 타 장치로의 배포 및 소비가 가능하여 소비자의 콘텐츠 이용에 대한 QoS(Quality of Service)를 향상시킬 뿐만 아니라, 콘텐츠에 대한 소비 및 이용 증가에 따른 IPTV 사업의 발전 및 활성화에 도움이 될 것이다.

• 방송공학회논문지
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• 제14권2호
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• pp.219-227
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• 2009

H.264/AVC에서 각 블록은 블록의 특성을 고려하여 적응적으로 양자화 파라미터(QP)를 선택하여 양자화를 수행한다면, 개선된 화질을 기대할 수 있다. 본 논문에서는, 블록 기반의 적응적인 QP 선택 방법은 주변 블록들의 지그재그 스캔 된 정수 변환 계수의 비트량과 현재 블록의 QP 값 변화를 이용하여 화질을 개선하도록 제안된다. 제안된 방법은 QP 값의 변화를 디코더로 전송하지 않고, 인코더에서와 같은 방법으로 디코더에서 직접 처리한다. 제안된 방법의 실험 결과는 H.264/AVC에 비하여 대략 $0.1{\sim}0.3\;dB$ 정도의 성능 향상을 보인다.

• 한국콘텐츠학회논문지
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• 제6권10호
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• pp.107-113
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• 2006

H.264의 인트라 프레임 에러복원기법은 상하좌우 인접한 블록의 픽셀을 사용하여 거리의 가중치 평균값으로 손실된 블록을 복원한다. H.264의 인트라 프레임 에러복원기법은 주변블록 픽셀의 간단한 평균값을 이용하여 복원하므로 심각한 블러링 현상이 발생하고 화질 저하의 문제를 야기한다. 이를 개선하기 위하여 본 논문에서는 주변블록의 픽셀 정보를 이용하여 손실된 블록의 주된 에지 방향을 추정하고, 통계값을 이용한 방해함수의 결과 값으로 에지 방향 기반의 보간법과 가중치 평균 보간법을 적응적으로 선택하여 복원하는 방법을 제안한다. 에지방향 기반의 보간법에서는 선택된 주된 에지방향과 상하좌우 각각의 주변블록의 에지방향들 간의 상호관계를 고려함으로써 최종적으로 최적 에지 방향을 선택하여 성능을 향상시킨다. 제안된 방법은 영상에 따라 H.264 에러복원기법보다 객관적인 화질이 $0.5{\sim}2.0dB$ 정도의 PSNR 향상을 보였다.

• 한국생산제조학회지
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• 제21권3호
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• pp.459-464
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• 2012

The point of impact, the shot group, and the flight traces depend on the combination of unique features which decide moving traces of the arrow (paradox of the archer, length of the arrow shaft, weight, angle of the feather, and spline of the arrow shaft). The more dense the impact points in the shot group and the earlier elimination of paradox of the archer, the higher assessment is given for the product. However, there is no way to objectively assess the efficiency and quality of the arrow, and there is no numeric data to be used as the basis for comparison with other products. Although capturing the images of flying arrow using a high-speed motion picture camera is possible, we are limited to observation from specific view angle only. Hence, the criteria for efficiency and quality assessment are mostly based on subjective opinions of experts or hunters, or review on consumers' remarks. In this paper, we propose a hardware composition that are based on three detection frames consisting of line lasers and photo diode arrays without the high-speed motion picture camera. Predicated on measured coordinates data, a nobel method for the archer's paradox measurement, a key parameter that determine the arrow's trajectory, and corresponding numerical analysis model is proposed.

• 대한의용생체공학회:의공학회지
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• 제19권4호
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• pp.351-360
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• 1998

아날로그 감마카메라에 비해 디지털 카메라는 Q.C가 편리하고, Calibration과 조작이 매우 쉬운 장점들을 갖고 있어 영상 질을 향상시킬 뿐만 아니라 진단의 정확도를 높일 수 있다. 더욱이, 디지털 카메라로 획득한 디지털 영상은 PACS(Picture Archiving and Communication System) 뿐만 아니라 원격진료에도 활용될 수 있다. 그러나, 많은 병원들이 아직도 아날로그 카메라를 사용하고 있고 이들을 디지털 카메라로 대체하기는 어려운 상황에 있다. 본 연구는 아날로그 감마카메라를 디지털화 할 수 있는지의 가능성을 보는 것이었다. 카메라를 디지털화 한 후 균일도 계수능력 등의 물리적 특성을 측정하였다. 임상에서의 사용 가능성을 보기 위해 아날로그 시스템과 디지털 시스템을 동시에 연결하여 임상 데이터들을 획득하였다. 이들의 결과는 임상환경에서 아날로그 카메라를 디지털화 하 수 있다는 가능성을 보여주었다.

• 한국의료질향상학회지
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• 제7권2호
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• pp.204-216
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• 2000

Background : There has been a concern that the quality of care provided to end-stage renal disease (ESRD) patients in the United States may not be as good as recommended. This paper illustrates a composite measure to assess, the quality of care received by ESRD patients undergoing in-center hemodialysis by incorporating outcomes for 4 major treatment areas. The 4 treatment areas are: dialysis treatments, anemia control, nutritional management, and blood pressure control. Methods : The major data source for the study was the United States Renal Data System (USRDS) Dialysis Morbidity and Mortality Study Wave 1 (DMMS-1) d Sixteen categories of a composite quality indicator were constructed by combining 4 dichotomous variables (16=2*2*2*2). representing the optimal vs. less than optimal level of outcome for each of the 4 treatment outcome measure respectively. Optimal outcome level for each treatment area was defined based on the recommendation from the National Kidney Foundation: (a) delivered dialysis doses (Kt/V) ${\geq}$ 1.2; (b) hematocrit level ${\geq}$ 30%; (c) serum albumin concentration ${\geq}$ 3.8g/dl ; and (d) blood pressure of <140 / <90mmHg. The 16 quality indicator were ranked according to their relative quality weights, which were estimated from its association with the relative risk of survival, adjusting for patient's baseline severity and dialysis facility characteristics. Results : Out of the entire sample of 2,179 patients, only 229 (10%) meet th recommended outcome levels for all 4 treatment areas. Overall, the study patients were distributed evenly over the 16 quality indicators, indicating a great variation in the quality of ESRD care. It appears that the rank of the 16 quality-indicators is driven by serum albumin concentration, suggesting that serum albumin concentration may be the most powerful predictor of ESRD patient survival among the 4 outcome measures. Conclusion : The developed quality indicator has the advantage of describin a range of care for dialysis patients and thus providing a more complete picture of care as compared to previous studies that have focused on only single or few components of the ESRD care.

• 품질경영학회지
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• 제50권4호
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• pp.863-876
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• 2022

Purpose: The purpose of this study is to propose the product quality satisfaction index based on multiple linear regression using customer reviews. Methods: The proposed framework is composed of four steps. First, we collect online reviews and divide it into insight phrases. The insight phrases are classified using product attribute dictionary and sentiment analysis is conducted. Second, the importance of attributes is calculated in consideration of both regression coefficient and frequency. Third, the positive rate is calculated concerning sentiment analysis result. Therefore, the quality satisfaction index is measured by the weighted sum of importance and positive rate in the last step. Results: We conduct a case study using 2-years(2020, 2021) of Samsung TV reviews to confirm the effectiveness of the proposed methodology. As a result, we found that Picture quality is the most crucial attribute in TV evaluation. The importance of Gaming and content has grown up as the positive rate has also increased. Therefore, the overall satisfaction of TV has increased in 2021 compared to 2020. Conclusion: The result of this study shows that the proposed index reveals the customer's mind efficiently and can be explained by the importance and positive rate of each attribute. By using the proposed index, companies are able to improve and the priority of improvement can be determined.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(4)
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• pp.199-202
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• 2001

A current TV-OUT format is quite different from that of HDTY or PC monitor in encoding techniques. In other words, a conventional analog TV uses interlaced display while HDTV or PC monitor uses Non-interlaced / Progressive-scanned display. In order to encode image signals coming from devices that takes interlaced display format for progressive scanned display, a hardware logic in which scanning and interpolation algorithms are implemented is necessary. The ELA (Edge-Based Line Average) algorithm have been widely used because it provided good characteristics. In this study, the ADI(Adaptive De-interlacing Interpolation) algorithm using to improve the algorithm which shows low quality in vertical edge detections and low efficiency of horizontal edge lines. With the De-interlacing ASIC chip that converts the interlaced Digital YUV to De-interlaced Digital RGB is designed. The VHDL is used for chip design.