• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.5C
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• pp.476-485
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• 2003

This paper proposers a preprocessing approach to improving the quality of the music produced by the EVRC(enhanced variable rate codec) which is one of the CDMA(Code Division Multiple Access) voice codecs. Since the EVRC is optimized only for speech signals, it can deteriorate the quality of the music passed through it. One of the problems with the EVRC-coded music is time-clipping, which usually occurs when subsequent frames are encoded at Rate l/8. Since the EVRC determines the bit rate for an input frame based on the long-term prediction gain, we increase the long-term prediction gain in order for the most of the frames to be encoded at Rate 1 or Rate 1/2. Experimental results show that the approach works well on music signals and the number of time-clipped frames is considerably reduced.

• The Journal of the Acoustical Society of Korea
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• v.40 no.3
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• pp.247-253
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• 2021

Directional ultrasonic speakers that are used to hear sound only in a specific area have been continuously researched on various improvements in terms of sound quality and cost compared to general speakers. In this paper, we propose a DSP based hybrid-type ultrasonic speaker that can be heard at the same time as a general speaker in order to compensate for the sound in the low-band range, considering that it is difficult to hear the low-band sound below 500 Hz due to the sensor characteristics of the ultrasonic speaker. In the case of the system that is implemented by simply connecting a general speaker and an ultrasonic speaker, there are issues of high cost and difficulties of control as two amplifiers are used to playback ultrasonic and general sound sources. In addition, sound quality deteriorates due to the difference in playback time between ultrasonic and general sound sources. In order to improve issues of cost, control and sound quality, we developed hybrid-type ultrasonic speaker with a DSP based amplifier that can simultaneously playback by synchronizing the general sound source with the regenerated ultrasonic sound source, in addition to implement the existing CODEC functions such as Dynamic Range Control (DRC) and Equalizer (EQ).

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.16 no.2
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• pp.69-76
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• 2023

A high-quality audio/voice codec using the MDCT/IMDCT process can perfectly restore the current frame through an overlap-add process with the previous frame. In the overlap-add process, an algorithm delay equal to the frame length occurs. In this paper, we propose a MDCT/IMDCT process that reduces algorithm delay by using a variable phase shift in MDCT/IMDCT process. In this paper, a low-delay audio/speech codec was proposed by applying the low delay MDCT/IMDCT algorithm to the ITU-T standard codec G.729.1 codec. The algorithm delay in the MDCT/IMDCT process can be reduced from 20 ms to 1.25 ms. The performance of the decoded output signal of the audio/speech codec to which low-delay MDCT/IMDCT is applied is evaluated through the PESQ test, which is an objective quality test method. Despite of the reduction in transmission delay, it was confirmed that there is no difference in sound quality from the conventional method.

• Korean Journal of Social Welfare
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• v.66 no.1
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• pp.221-249
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• 2014

This paper has the objectives to define the concept of 'Good Care' which is the service goal we are aiming essentially for the improvement of long-term care service quality, to find out the components for 'Good Care', and to explore the conditions that create a good care. In addition, we tried to find the answer about what is the best way to measure the service quality. For this, I referred the advanced researches which explored the fundamental properties of care and tried to find the answer from the accumulated wisdom of service field through the 5-year long term care service experience. As a result of research, the good care can be defined as helping someone to be able to maintain his own life as maximum as possible with the goal to assure total quality life. The most important condition for good care is making 'a good care relationship'. Without damaging the relationship between care provider and care receiver, the individualized service focusing on the demand of care receiver based on mutual reliability, mutual respect and smooth communication should be provided. For the evaluation system, it is reasonable to set the standard according to the size of each institution for the core quality of facility service and establish the certification system of absolute standard to carry out the quantitative evaluation rather than the relative evaluation in the whole. For the part over the absolute certification standard, it is reasonable for each institution to characterize its own characteristics autonomously and carry out the qualitative evaluation for this. For the evaluation of home visit care service, it is recommended to contain the evaluation contents such as user satisfaction, satisfaction of care worker, how well the case management system of home care service center is operated etc.

• The Journal of the Acoustical Society of Korea
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• v.41 no.1
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• pp.87-98
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• 2022

The purpose of this study is to develop the Korean version of Music-Related Quality of Life (K-MRQoL) for the elderly. The K-MRQoL consisted of Musical Ability, Attitude, Activity Frequency (PART 1) and Musical Ability, Attitude, Activity Important (PART 2). Each subcategory consists of Music Perception with 11 items and Music Engagement with 7 items. The validity and reliability of K-MRQoL were measured with Pearson's and Cronbach's alpha correlation coefficients and Independent t-test in total 30 elderly with normal hearing and 30 elderly with hearing loss from local welfare Centers and nursing homes. The correlation coefficients between total scores and PART 1 and PART 2 ranged from .701 to .948 and from .598 to .926, respectively. The internal consistency between total and Part 1 and Part 2 ranged from .846 to .931 and from .838 to .918, respectively. The test-retest correlations were .979, .970, and 979 for total, PART 1, and PART 2, respectively. The correlation between K-MRQoL and Quality of Communication Life Scale was .449. There were significant differences in total, PART 1, and PART 2 between the elderly with normal hearing and hearing loss. This indicates that the K-MRQoL can be used as a useful clinical tool to evaluate Music-related Quality of Life in the elderly with normal hearing or hearing loss.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.78-86
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• 2017

The new businesses started by the companies usually results in being unsuccessful. The main reasons for that are either aiming targeting wrong customers, unsatisfaction of customers' requesting quality standards, or taking wrong actions against the competitors in the market. Therefore, companies should aim the targets for the newly developing products based on the fulfilling values for the customers when they start the new businesses, and should take good cares for risk managements at the each step of the new business to prevent the failure in advance. In addition to that, the companies starting new businesses not only need to take the customers attributes (CA) into account, but they also should apply the new technologies as one system to initiate a new business to satisfy the basic wants of the customers. This article suggests the New Product Development Pursuing Model using the Indicative Planning methodology and the Quality Management tools. The New Product Development Pursuing Model would be completed by the following steps as below; 1. Drawing the CTQ (Critical To Quality) for setting up the new product development objectives by : i) using the VOC (Voice Of Customers) obtained by the QFD (Quality Function Deploypment) if the market is mature, ii) applying AHP (Analytic Hierarchy Process) to information in the QIS (Quality Information System) if the market is unmature to get enough need information of the customers. 2. Risk Management in NPD : The NPD pursuing model consisted of the IP (indicative planning) is suggested not by the process of top-down-way mandatory planning process, but by the tools used in the administrative science and economic fields, namely by governance. The companies could apply innovative methodology for new products development processes to fulfil the customers satisfaction in the fields, through the CA (Contingency Approach) of the NPD (New Product Development) process.

• The Journal of Advanced Prosthodontics
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• v.5 no.1
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• pp.29-35
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• 2013

PURPOSE. To longitudinally assess the quality of life in maxillectomy patients rehabilitated with obturator prosthesis. MATERIALS AND METHODS. Thirty-six subjects were enrolled in the span of 16 months, out of which six were dropouts. Subjects (age group 20-60 years) with maxillary defects, irrespective of the cause, planned for definite obturator prosthesis, were recruited. The Hindi version of European Organization for Research and Treatment of Cancer, Head and Neck version 1 of Quality of Life Questionnaire was used before surgical intervention and one month after definitive obturator. Questionnaire includes 35 questions related to the patient's physical health, well being, psychological status, social relation and environmental conditions. The data were processed with statistical package for social science (SPSS). Probability level of P<.05 was considered statistically significant. RESULTS. The quality of life after rehabilitation with obturator prosthesis was 81.48% (${\pm}13.64$) on average. On item-level, maximum mean scores were obtained for items problem with teeth ($1.87{\pm}0.94$), pain in mouth ($1.80{\pm}0.92$), trouble in eating ($1.70{\pm}0.88$), trouble in talking to other people ($1.60{\pm}1.22$), problems in swallowing solid food ($1.57{\pm}1.22$) and bothering appearance ($1.53{\pm}1.04$); while minimum scores were obtained for the items coughing ($1.17{\pm}0.38$), hoarseness of voice ($1.17{\pm}0.53$), painful throat ($1.13{\pm}0.43$), trouble in having social contacts with friends ($1.10{\pm}0.40$) and trouble having physical contacts with family or friends ($1.10{\pm}0.31$). CONCLUSION. Obturator prosthesis is a highly positive and non-invasive approach to improve the quality of life of patients with maxillectomy defects.

• Journal of the Korea Society of Computer and Information
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• v.14 no.3
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• pp.121-131
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• 2009

BcN provides a wide variety of high-quality multimedia services such as broadcasting and communication convergence services. But the quality degeneration is observed in BcN when we use broadcasting and communication convergence service via more than one network of different internet service providers. In this paper, a QoS management system which is able to measure and maintain objectively the quality-related information in overall networks is proposed. The proposed QoS management system is tested on the pilot networks of BcN consortiums by measuring the quality of voice and video experienced by the actual users of the commercial video phone services. The result of the experiment shows that it is possible to figure out service qualify between a user and a service provider by analyzing the information from agents. The per-service traffic information collected by probes is proved to be useful to pinpoint the party responsible for the loss of the service qualify in case of the services including different service providers. As the result of the experiment, it is shown that the proposed QoS management system would play a key role of resolving the quality dispute, which is one of the important issues of QoS-guaranteed BcN.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.316-323
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• 2002

In this paper, we analyze the call control scheme that is using buffer at new call and handoff call for non-uniform traffic load distribution, the multiple cell environments and the multiple types of services such as voice and data service. Considering the facts, the call admission control method using the effective bandwidth concept is employed in this paper, The bandwidth for a new call and a handoff call is allocated by the number of mobile station and dynamically assigned by taking account of the blocking rate of new calls and the dropping rate of handoff calls. The call control procedure is experimented through a simulation study by dynamically the bandwidth to new and handoff calls based on the blocking rate and the dropping rate. The results show our call control scheme can get a good quality of service for mobile users.

• ETRI Journal
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• v.37 no.2
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• pp.395-405
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• 2015

We address the problem of uncooperative person recognition through continuous monitoring. Multiple modalities, such as face, height, clothes color, and voice, can be used when attempting to recognize a person. In general, not all modalities are available for a given frame; furthermore, only some modalities will be useful as some frames in a video sequence are of a quality that is too low to be able to recognize a person. We propose a method that makes use of stochastic information updates of temporal modalities and environment estimators to improve person recognition performance. The environment estimators provide information on whether a given modality is reliable enough to be used in a particular instance; such indicators mean that we can easily identify and eliminate meaningless data, thus increasing the overall efficiency of the method. Our proposed method was tested using movie clips acquired under an unconstrained environment that included a wide variation of scale and rotation; illumination changes; uncontrolled distances from a camera to users (varying from 0.5 m to 5 m); and natural views of the human body with various types of noise. In this real and challenging scenario, our proposed method resulted in an outstanding performance.