• 한국음향학회지
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• 제8권5호
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• pp.59-69
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• 1989

• Journal of Oral Medicine and Pain
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• 제46권4호
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• pp.109-116
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• 2021

Purpose: Xerostomia is subjective feeling of dry mouth. It is complicated and multifactorial, which burdens clinicians in diagnosis and treatment of the problem. The goal of this study was to discuss the clinical importance of salivary flow rate, pH and subjective symptoms for evaluating oral dryness among young healthy male subjects. Methods: Thirty male participants were recruited in this study (mean age±standard deviation of 25.70±1.84). All participants completed 'Xerostomia Inventory' to measure subjective oral dryness scores. Unstimulated saliva and stimulated saliva were collected from each participant twice a day at 12:00 pm and 5:00 pm, using spitting method. Salivary flow rates and pH were measured immediately after collection. Relationship between objective and subjective measurements were analyzed. Results: There were excellent intra-examiner reliability for salivary flow rate and pH and good internal consistency for Xerostomia Inventory. Objective measurements and subjective symptoms did not exhibit positive association. Salivary flow rate in unstimulated and stimulated condition showed positive association and also for salivary pH. Stimulated salivary flow rate also presented positive correlation with stimulated salivary pH. Conclusions: Comprehensive assessment of objective measurements and subjective symptoms may be complimentary for assessing oral dryness, which would assist in implementing early interventions to improve patient's quality of life.

• 대한간호학회지
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• 제40권2호
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• pp.182-190
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• 2010

Purpose: This study was done to identify self-directed learning readiness, achievement goal orientations, learning satisfaction and learning achievement, and to evaluate the factors affecting learning achievement for nursing students using a web-based Health Assessment e-Book. Methods: The research design was a cross-sectional study with a structured questionnaire and data were collected before using the web-based Health Assessment e-Book and 1 week after finishing. The participants were 80 nursing students who were taking the Health Assessment class from March to June 2009. Results: Mean score for subjective learning achievement was 31.26 and for objective learning achievement, 69.25. Subjective and objective learning achievement were positively correlated with self-directed learning readiness, mastery goal, attitude toward distance education, and learning satisfaction. In subjective learning achievement, learning satisfaction and mastery goal were significant predictive factors and explained 64% of the variance. Objective learning achievement was significantly predicted by learning satisfaction and self-directed learning readiness, which explained 24% of the variance. Conclusion: Learning satisfaction, mastery goal and self-directed learning readiness were found to be very important factors associated with learning achievement for nursing students using a web-based Health Assessment e-Book. To provide high quality and effective web-based courses and to improve nursing students' learning achievement and learning satisfaction, educators should consider the learner's characteristics from the initial stages of lecture planning.

• Journal of Audiology & Otology
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• 제24권4호
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• pp.180-190
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• 2020

Background and Objectives: Although many studies have evaluated the effect of the digital noise reduction (DNR) algorithm of hearing aids (HAs) on speech recognition, there are few studies on the effect of DNR on music perception. Therefore, we aimed to evaluate the effect of DNR on music, in addition to speech perception, using objective and subjective measurements. Subjects and Methods: Sixteen HA users participated in this study (58.00±10.44 years; 3 males and 13 females). The objective assessment of speech and music perception was based on the Korean version of the Clinical Assessment of Music Perception test and word and sentence recognition scores. Meanwhile, for the subjective assessment, the quality rating of speech and music as well as self-reported HA benefits were evaluated. Results: There was no improvement conferred with DNR of HAs on the objective assessment tests of speech and music perception. The pitch discrimination at 262 Hz in the DNR-off condition was better than that in the unaided condition (p=0.024); however, the unaided condition and the DNR-on conditions did not differ. In the Korean music background questionnaire, responses regarding ease of communication were better in the DNR-on condition than in the DNR-off condition (p=0.029). Conclusions: Speech and music perception or sound quality did not improve with the activation of DNR. However, DNR positively influenced the listener's subjective listening comfort. The DNR-off condition in HAs may be beneficial for pitch discrimination at some frequencies.

• 대한청각학회지
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• 제24권4호
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• pp.180-190
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• 2020

Background and Objectives: Although many studies have evaluated the effect of the digital noise reduction (DNR) algorithm of hearing aids (HAs) on speech recognition, there are few studies on the effect of DNR on music perception. Therefore, we aimed to evaluate the effect of DNR on music, in addition to speech perception, using objective and subjective measurements. Subjects and Methods: Sixteen HA users participated in this study (58.00±10.44 years; 3 males and 13 females). The objective assessment of speech and music perception was based on the Korean version of the Clinical Assessment of Music Perception test and word and sentence recognition scores. Meanwhile, for the subjective assessment, the quality rating of speech and music as well as self-reported HA benefits were evaluated. Results: There was no improvement conferred with DNR of HAs on the objective assessment tests of speech and music perception. The pitch discrimination at 262 Hz in the DNR-off condition was better than that in the unaided condition (p=0.024); however, the unaided condition and the DNR-on conditions did not differ. In the Korean music background questionnaire, responses regarding ease of communication were better in the DNR-on condition than in the DNR-off condition (p=0.029). Conclusions: Speech and music perception or sound quality did not improve with the activation of DNR. However, DNR positively influenced the listener's subjective listening comfort. The DNR-off condition in HAs may be beneficial for pitch discrimination at some frequencies.

• Journal of Information Processing Systems
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• 제13권3호
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• pp.448-463
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• 2017

Multimedia is a ubiquitous and indispensable part of our daily life and learning such as audio, image, and video. Objective and subjective quality evaluations play an important role in various multimedia applications. Blind image quality assessment (BIQA) is used to indicate the perceptual quality of a distorted image, while its reference image is not considered and used. Blur is one of the common image distortions. In this paper, we propose a novel BIQA index for Gaussian blur distortion based on the fact that images with different blur degree will have different changes through the same blur. We describe this discrimination from three aspects: color, edge, and structure. For color, we adopt color histogram; for edge, we use edge intensity map, and saliency map is used as the weighting function to be consistent with human visual system (HVS); for structure, we use structure tensor and structural similarity (SSIM) index. Numerous experiments based on four benchmark databases show that our proposed index is highly consistent with the subjective quality assessment.

• 정보처리학회논문지D
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• 제10D권4호
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• pp.719-726
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• 2003

대표적인 소프트웨어 프로세스 심사 모델로서 ISO/IEC 15504(일명 SPICE)와 CMM은 숙련된 전문 심사원을 통하여 소프트웨어 프로세스의 능력수준을 결정한다. 그러나 이들 모델들은 프로세스 측정을 위한 체계적인 메트릭스를 제공하지 않으므로 심사원은 심사대상 프로세스의 정량적인 수준 측정을 위하여 주관적인 판단을 통해 프로세스를 평가해 오고 있다. 본 논문에서는 프로세스의 정량적이고 객관적인 측정을 위하여 기초 품질 메트릭스를 정의하고 CMM과 ISO/IEC 15504에서 정의한 프로세스 분야에 대한 표준 메트릭스를 제안한다. 또한 표준 메트릭스를 조직에 적용하기 위한 프로세스 측정 절차와 가이드라인을 제시한다. 이를 통해서 조직 내의 프로세스에 대한 객관적 평가와 수준을 결정할 수 있으며 향후 개선을 위한 관리가 용이하다.

• 방송공학회논문지
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• 제24권6호
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• pp.1085-1095
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• 2019

본 논문에서는 저해상도 감시(surveillance) 비디오에 대한 주관적 화질 평가를 수행한다. 본 논문은 저해상도 영상에 맞는 초협대역 전송 환경을 고려하여 비디오 압축을 수행한 다음, 압축된 비디오의 주관적 화질 성능을 측정하였다. 데이터의 일반성을 확보하기 위해 다양한 시/공간 복잡도를 가지는 감시 비디오를 수집하였다. 저해상도 감시 비디오 압축은 H.265/HEVC로 수행되었으며 3개의 목표 비트(20, 45, 65 kbps)에 대해 압축을 수행했다. 주관적 화질 평가 결과, 수집한 대부분의 저해상도 감시 비디오는 45 kbps이상으로 압축될 경우 주관적 화질 열화가 거의 발생하지 않는 것으로 나타났다. 뿐만 아니라, 기존 개발된 객관적 영상 화질 측정 방법을 이용해 예측된 화질과의 상관관계를 비교하는 실험을 진행했고, 실험 결과 현존하는 대부분의 객관적 화질 측정 방법이 초협대역 전송 조건에서 저해상도 감시 비디오의 화질을 제대로 예측하지 못하는 것을 확인하였다. 이는 초협대역 전송 기반 저해상도 감시 비디오에 대한 새로운 객관적 영상 화질측정 기법이 개발되어야 함을 시사한다.

• 인터넷정보학회논문지
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• 제22권2호
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• pp.51-58
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• 2021

가상 현실 공간에서 실사 영상 및 그래픽 환경에 대해 사용자 움직임에 대응하는 영상을 제공하는 three degrees of freedom plus(3DoF+) 및 six degrees of freedom(6DoF) 시스템은 실감형 미디어를 제공하기 위해 서로 다른 위치에서 동시에 취득된 다수의 초고화질 및 고해상도의 영상 집합 전송을 요구한다. 다수의 영상들을 사용해 사용자 시점 영상을 생성할 때, 기존의 영상 압축 코덱에서 발생했던 것과는 다른 형태의 품질 저하가 발생하여 기존의 영상 품질 평가 기법들은 3DoF+ 및 6DoF 시스템 평가에 적합하지 않다. 본 논문은 3DoF+ 환경에서 합성된 사용자 시점 영상에 대한 다양한 객관적 영상 품질 평가 기법에 대한 성능 평가를 소개한다. 또한, 기존의 객관적 영상 품질 평가 기법을 조합하여 주관적인 평가와 상관관계를 더욱 높인 평가 기법인 슈퍼 메트릭(super metric)을 제시한다. 3DoF+ 몰입형 비디오 평가 시 제안한 기법을 사용하였을 때, 주관적 평가 점수와의 상관관계에서 peak signal-to-noise ratio(PSNR) 대비 0.4513의 상승이 있었음을 확인하였다.

• 방송공학회논문지
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• 제18권3호
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• pp.416-424
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• 2013

최근 3DTV의 화질 평가와 관련된 국제 표준이 국제전기통신연합과 VQEG 등을 중심으로 진행되고 있다. 기존의 2D 디스플레이와 달리 3D 디스플레이는 영상의 재생 방식과 전달 방법에 따라 편광안경, 셔터안경, 무안경 방식 등 여러 종류가 있으며, 다양한 기술들이 개발되고 있다. 본 논문에서는 여러 방식의 3D 디스플레이 기기를 사용하여 일관된 3D 화질 평가가 가능한지 조사하기 위하여, 상이한 디스플레이를 대상으로 주관적 화질 평가 실험을 수행하였다. 실험 결과 각 디스플레이에서 측정된 화질점수는 영상의 재생 방식이나 디스플레이의 크기에 관계없이 매우 높은 상관관계를 보였으며, 이는 다양한 디스플레이를 사용하여 열화신호의 체감 화질을 측정하는 경우 유사한 결과를 얻을 수 있음을 의미한다.