• 융합신호처리학회논문지
• /
• 제2권4호
• /
• pp.53-58
• /
• 2001

이동전화망을 위한 신뢰성 높은 객관적 통화품질평가 척도개발을 위하여 Bark Spectral Distortion Perceptual Speech Quality Measure의 성능을 분석하여 이 척도들을 실제 환경에서 수집된 음성 데이터에 대해서 실험한 결과, 성능의 저하가 나타났다. 본 논문에서는 인간의 심리음향학적 특성인 마스킹을 적용하는 방안을 제안하여 그 유효성을 실험으로 확인하였다. 이때, masking threshold 계산에 tone 신호를 사용하기 때문에 음성신호에 대하여 계산할 경우 문제점이 있을 수 있으므로 scaling 을 적용하는 새로이 제안하였다. 디지털 이동통신망에서 수집된 음성 데이터에 대한 성능평가 결과, 기존의 척도들 보다 더 높은 성능을 보임을 확인하였다.

• 한국멀티미디어학회논문지
• /
• 제5권4호
• /
• pp.405-414
• /
• 2002

본 논문에서는 이동전화망 환경 하에서의 음성의 통화품질 평가를 위해 마스킹 문턱치를 이용하는 객관적 음질평가법을 제안하고 실험을 통하여 그 유효성을 확인하였다. 현재까지 잘 알려진 BSD(Bark Spectral Distortion), PSQM(Perceptual Speech Quality Measure)등의 성능을 먼저 분석하였다. 그 결과, MOS(Mean Opinion Score)와의 상관성이 이동통신 환경하에서 문헌상에 보고된 결과보다 성능이 저하됨을 확인하였다. 이동통신 환경하에서 보다 효율적인 객관적 음질평가척도 개발을 위하여 제안된 방법에서는 인간의 심리음향학적 마스킹 현상을 이용하였고, 성능 평가시 비교대상인 주관적 음질척도로는 DMOS(Degradation MOS)를 사용하였다. 디지털 이동통신망에서 수집된 음성 데이터에 대한 성능평가실험을 수행한 결과, BSD와PSQM 같은 기존의 척도들에 비하여 평균 4%의 상관성능이 향상됨을 확인하였다.

• 한국통신학회논문지
• /
• 제17권8호
• /
• pp.881-890
• /
• 1992

본 논문은 음성 시스템과 통신망에서 이용되는 음성 품질 평가 모델의 구축을 위한 기본 연구로서, 음성 부호화 평가 방법 중 주관적 평가에서 발생되는 여러 문제점을 해결하여 안정된 객관적 평가값을 얻기위해서, 여러 객관적 평가량과 주관적 평가량을 상호 비교한 후, 주관적 평가값에 적합한 객관적 평가량을 검토하였다.

• 말소리와 음성과학
• /
• 제2권1호
• /
• pp.71-75
• /
• 2010

The PESQ is an objective speech quality evaluation measure that is known to have a high correlation with a subjective speech quality measure such as MOS. To examine whether it could be useful as an objective quality measure of synthetic speech, we carried out both subjective evaluation tests with MOS and DMOS and an objective evaluation test with PESQ for HMM-based Korean synthetic speech signals and analyzed the correlation between them. Experimental results have shown that the PESQ has correlations of 0.87 with MOS and 0.92 with DMOS. It means that the PESQ holds much promise for evaluating the quality of synthetic Korean speech.

• 음성과학
• /
• 제6권
• /
• pp.163-179
• /
• 1999

For the set up, management and repair of a mobile communication system, continuous estimation of speech quality is required. Speech quality measurement can be conducted by listener's judgement in a subjective test such as MOS (Mean Opinion Score) test. However, this method is laborious, expensive and time-consuming, it is advisable to predict subjective speech quality via objective measures. This paper presents a robust objective speech quality measure, PLP-CMS (Perceptual Linear Predictive-Cepstral Mean Subtraction), which can predict subjective speech quality in mobile communication systems. PLP-CMS has a high correlation with subjective quality owing to PLP (Perceptual Linear Predictive) analysis and shows a robust performance not being influenced by PSTN (Public Switched Telephone Network) channel effects due to CMS (Cepstral Mean Subtraction). To prove the performance of our proposed algorithm, we carried out subjective and objective quality estimation on speech samples which are variously distorted in a real mobile communication system. As a result, we demonstrated that PLP-CMS has a higher correlation with subjective quality than PSQM (Perceptual Speech Quality Measure) and PLP-CD (Perceptual Linear Predictive-Cepstral Distance).

• 대한공간정보학회지
• /
• 제17권3호
• /
• pp.33-40
• /
• 2009

본 연구에서는 모자이크 영상에 대하여 정량적인 품질평가지수에 대한 적용 가능성을 제시하였다. 우선, 영상 품질평가를 위해 접합영상의 접합선을 이용한 연속성 평가와 색상을 이용한 유사성(similarity) 및 대비(contrast)를 이용하여 품질평가지수를 산정하였다. 선정된 품질평가 항목을 기반으로 최종적인 품질평가지수를 산정하여 실험자에 의한 주관적 평가와의 비교, 검증을 수행하였다. 그 결과 정량적 품질평가지수가 주관적 평가지수와 유사한 결과를 나타냄으로써 제시한 영상 품질평가지수를 이용하여 제작된 모자이크 영상에 대한 정량적이고 객관적인 모자이크 영상의 품질평가가 가능하다는 것을 보여주었다.

• 한국전문물리치료학회지
• /
• 제14권4호
• /
• pp.7-13
• /
• 2007

The purpose of this study was to investigate correlations among objective measurements of spasticity in patients with brain lesions. Thirty-two stroke and traumatic brain injury subjects participated in the study. Spasticity was quantified using the knee first flexion angle, relaxation index obtained from a pendulum drop test, and the amplitude of a knee tendon reflex test. Pearson's product correlation coefficient was used to examine relationships among these measurements of spasticity. There was a significant positive correlation between the relaxation index and knee first flexion angle in patients with brain lesions (r=.895, p<.01). There was also significant negative correlation between the amplitude of knee tendon reflex and relaxation index (r=-.612, p<.01), and between amplitude and knee first flexion angle (r=-.537, p<.01). Thus, it is possible to use the knee first flexion angle as an objective measure of spasticity, rather than relaxation index, which is more complicated to obtain. Further studies are needed to explore the effects of functional improvement and long-lasting carryover effects of spasticity using a simple objective measure such as the knee first flexion angle from a pendulum test.

• Management Science and Financial Engineering
• /
• 제6권1호
• /
• pp.37-63
• /
• 2000

An important objective of pull-based production control is to achieve synchronized and smooth production flow in a multi-stage system that is subject to uncertainty. To our knowledge, previous research has not generated a performance measure that captures this objective of pull-based probased production control system. This performance material with respect to the instant when the operation is required. We examine the issue of asynchronous waste in a two-stage kanban control system.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2002년도 학술발표회 논문집(II)
• /
• pp.829-836
• /
• 2002

The paper presents a multi-objective genetic algorithm approach to the design of a water distribution network. The objectives considered are minimization of network cost and maximization of a reliability measure. In this study, a new reliability measure, called network resilience, is introduced. This measure mimics a designer's desire of providing excess power at nodes and designing reliable loops with practicable pipe diameters. The proposed method produces a set of Pareto-optimal solutions in the search space of cost and network resilience. Genetic algorithms are observed to be poor in handling constraints. To handle constraints in a better way, a constraint handling technique that does not require a penalty coefficient and applicable to water distribution systems is presented. The present model is applied to two example problems, which were widely reported. Pipe failure analysis carried out on some of the solutions obtained revealed that the network resilience based approach gave better results in terms of network reliability.

• 전자공학회논문지B
• /
• 제30B권10호
• /
• pp.42-49
• /
• 1993

In this paper, we evaluate the quality of synthesized speech by rule using the LPC CD as a objective measure, and then compare the test result with the subjective one. Speech used for the test consists of 108 words which are selected by word construction method using Korean attribute and frequency distribution, synthesized by demi-syllable rule. By evaluating the quality of synthesized speech by reule objectively, we have tried to resolve the problems such as lots of evaluation time, expansion of test scale, and variables of analysis result arised by subjective measure. We have, also, proved the validity of the objective test using the LPC CD, by comparing intelligibility which is the index for the subjective quality evaluation of synthesized speech by rule with MOS. From this results, we can provide a guide for quality assessment that would be useful in the R&D of synthesis method and the commercial products using synthesized speech.