• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.34-40
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• 2010

As internet spread widely, various service which use the internet have been provided. One of the service is a internet phone. Its usage is increasing by the advantage of cost. But it has a falling off in quality of speech. because it use packet switching method while existing telephone use circuit switching method. Although vocoder use PLC (Packet Loss Concealment) algorithm, it has a weakness of continuous packet loss. In this paper, we propose methods to improve a lowering in quality of speech under continuous loss of packet by using PLC algorithm used in advanced G.729 and G.711. The proposed methods are LP (Linear Prediction) parameter interpolation, excitation signal reconstruction and excitation signal gain reconstruction. As a result, the proposed method shows superior performance about 11%.

• Journal of Korean Public Health Nursing
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• v.12 no.1
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• pp.103-115
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• 1998

As the studies that smoking can be a major cause to various diseases have been made, many following researches on the outcome of stop-smoking education were in progress. Even though researches based on the knowledge about smoking and status about the teenagers were prevalent, the research based on the outcomes in long time basis were not in progress. Therefore, I tracked the people who went through 5-Day Stop-Smoking School that has taught through complexed structure of behavioral, intellectual, and psychological education. I made researches on the average of success and the hardest point during their efforts to stop just to show the necessity of going through re-education. The objectives of this study were the ones who have completed the education on the years 1990, 1991. 47 were selected from 364 people that completed the training, and who were able to be contacted on the phone line. This study was conducted from 27 Oct. to 7 Nov. 1997 through verbal interviews based on the questionnaire. The questionnaire used here was made by myself, assisted by my professor. Analysis was made through unstructured open questions. The data was analyzed using SPSS program. The major results were as follows ; 1) General characteristics of the objectives are $97.0\%$ were male, $17\%$ ages below 40s, $34\%$ in the age group of 40s, and $48.9\%$ over 50s. Religiously christian 340/0, buddhist $19.1\%$, no religion or any other reason $46.8\%$. Status married $93.6\%$, unmarried $6.4\%$. There is someone smoking in the family $36.2\%$, no one smokes $63.8\%$. Reputation salary men $55.3\%$, personal business $27.7\%$. 2) The average of success is $42.6\%(20/47)$, the failure is $57.4\%$. 3) The results from the study 'When was the hardest point in the process of stop smoking' : For the successors the first week $33.3\%$, after the first week $66.7\%$. For the failures the first week $55\%$, after first week $45\%$(Statistics not precisely done), the most effective element that helped through the hardest point was the family $40\%$, personal determination $30\%$. 4) The necessity of re-education : Successors needed $55\%$, not needed $45\%$. Failures needed $48.1\%$, not needed $51.9\%$(Statistics not precisely done). The perfect time for reeducation : Successors in 6 months $50\%$, irregular time basis $50\%$. Failures in six months $36.4\%$, after six months $27.3\%$, irregular time basis $36.4\%$(Statistics not precisely done). Synthesizing the result of the study can't generalize the long-term effect of the stop-smoking due to the number of the objectives,. but recognize the fact that 47.6 have experienced success, and also the self-determination and the support from the family are desirable. Seeing the fact that both are great motivation to stop smoking. Since the first week is necessary. The necessity of re-education is rather high, so this education should be planned to be done repeatedly in a long term along with close observation, instead of short education.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.1
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• pp.23-37
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• 1999

This study is to understand and to describe the power that a nurse experiences on nursing practice and then. to present a basic data for nurse's power-development, power improving and empowering. Ethnography was used to understand and to describe experience on exercising various powers occurred on nursing practice. and to analyze and to understand the meaning of a nurse's power. The objects was nurses. Ten nurses who have more than three year's experience were selected as objects from Cuniversity's hospital in Seoul from May of 1996 to August of 1997 through in-depth interview. participant observation, and phone interview. Instruments werw a portable recorder and field notes. I described a case appeared in a data using Agar's 'Pencil and scissors' method right after collecting materials. Then, Idescribed a theme discovered commonly. Followings are the results of the study. 1. There were three categories of relationships with main objects when nurses exercised their power on their practices: a therapeutic caring relationship with patients, a relationship of companion, vertical cooperation, and a constituent person with a doctor, and a relationship of cooperation, and a constituent person with administrative workers and medical technicians. 2. There were many types of nurse's power, tactics and various patient's responses about them. 1) Types of nurse's power to patients were giving information, controling environment, helping for cure, emotional support, and performing discretion. 2) Nurse's tatics for performing power were positive tactics neutral tactics, and negative tactics. 3) Patient's responses were appeared as compliance and noncompliance. Compliance were agreeing. taking nurse's advice, trusting, understanding, being admitted, exposuring himself, and appreciating. 3. There were types of nurse's power and performing tactics. 1) Types of power to a doctor were advice, informing, demanding and mediation. 2) Performings of tactics to a doctor were positive tactics, neutral tactics, and negative tactics. 3) Doctor's responses were appeared as accepting and unaccepting. Acceptings were taking in and appreciating, and unacceptings were denying nurse's advice and authoritative. 4. There were types of nurse's power and tactics about administrative workers and medical technicians and responses about them. 1) Types of power about administrative workers and medical technicians were suggestions and demands. 2) Power performings tactics were positive tactics.neutral tactics, and negative tactics. 3) Responses of administrative workers and medical technicians about nurse's power performing were appeared appeared as accepting and unacce pting. Acceptings were taking in, and unacceptings were denying. Therefore, it can be said that types of nurse's power and performing tactics on nursing practice and nurse's power based on responses of a patient, a doctor, an administrative worker, and a medical technicians are power or influence for agreeing, taking advice, trusting, understanding, exposuring himself, appreciating, and taking in to objects. The results of this study helped to understand nurse's power. I expect that this study will improve nure's power by using expert power, referent power, and legitimate power effectively among powers acmpanied with the origin and that nurses make ef-ort to improve professional knowledge and human nature so that they use this study as a chance to develope expert nursing practice.

• Journal of the Economic Geographical Society of Korea
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• v.23 no.1
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• pp.56-70
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• 2020

This study identifies the impact of social network service (SNS) on the spatial characteristics of retail stores locations in the hyper-connected society, which have been closely related to the everyday lives of urban residents. In particular, we focus on the changes in the spatial distribution of restaurants since the information retrieval process was added to the decision-making process of a consumer's restaurant selection. Empirically, we analyze restaurants in Seoul, Korea since the smart-phone was introduced. By applying the kernel density estimation and Moran's I index, we examine the changes in the spatial distribution pattern of restaurants during the last ten years for running, newly-open and closed restaurants as well as SNS popular ones. Finally, we develop a spatial regression model to identify geographic features affecting their locations. As the results, we identified geographical variables and online factors that influence the location of restaurants. The results of this study could provide important groundwork for food and beverage location planning and policy formulation.

• The Journal of the Acoustical Society of Korea
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• v.39 no.5
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• pp.461-467
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• 2020

In noisy and multi-speaker environments, the performance of speech recognition is unavoidably lower than in a clean environment. To improve speech recognition, in this paper, the signal of the speaker of interest is extracted from the mixed speech signals with multiple speakers. The VoiceFilter model is used to effectively separate overlapped speech signals. In this work, clustering by Probabilistic Linear Discriminant Analysis (PLDA) similarity score was employed to detect the speech signal of the interested speaker, which is used as the reference speaker to VoiceFilter-based separation. Therefore, by utilizing the speaker feature extracted from the detected speech by the proposed clustering method, this paper propose a speaker diarization system using only the mixed speech without an explicit reference speaker signal. We use phone-dataset consisting of two speakers to evaluate the performance of the speaker diarization system. Source to Distortion Ratio (SDR) of the operator (Rx) speech and customer speech (Tx) are 5.22 dB and -5.22 dB respectively before separation, and the results of the proposed separation system show 11.26 dB and 8.53 dB respectively.

• Journal of Convergence for Information Technology
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• v.10 no.11
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• pp.47-54
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• 2020

This study proposes an NFC-based payment system that considers user convenience while expanding the existing payment method for RFID-based individual food and logistics waste equipment. In line with this trend, I proposed to apply NFC to the existing RFID-based food meter to release the food in the meantime and to address the problem of re-carrying due to card loss, card not possessed, and non-filling, and the question that could not be identified by various cumbersome procedures. NFC's function alone has been certified for its convenience, which led to its introduction and research in the period of time. Of course, we need to negotiate fees with the transportation card company, but if we see a market share related to transportation card soon, we think smooth negotiations will take place. NFC method will be expanded to all phones with iPhone NFC opening. Therefore, in the next study, we intend to apply the payment system in NFC by linking with local currency, mobile vouchers, and card companies, which are being paid as respective payment means according to the recent emergency support system for COVID-19.

• Science of Emotion and Sensibility
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• v.17 no.3
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• pp.65-74
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• 2014

Due to recent interest in user experience and its significance, much research surrounding this theme is now being conducted. In this research, I investigated user experience during usage of a product and the satisfaction acquired by it, as well as the relationship between satisfaction of having used a product and whether the user would be more likely to purchase another product from the same company. The same experiment was conducted in South Korea and the United States of America in order to get more generalized experimental results. I found that amongst the six representative user emotions expressed while using a product, two of them correlated the most. First, 'Satisfaction in Usability' (the emotions aroused by satisfaction with usage or the practicality of the product); and second, 'Discomfort or Displeasure' (uncomfortable or unpleasant emotions expressed while using a product. The above two factors were found to be of the most influence concerning satisfaction of the product. Also 'Satisfaction in Usability' was found to be of the most influence in their preferability towards purchasing an item from the same company in the future. The significance of this finding is that aside from focussing on the attractiveness of the product's exteriors and design, one should be concerned on the ease of usage and effectiveness as well as usability of the product, all of which contribute to how efficiently a consumer will utilize the product. Furthermore, in agreement with previous research concerning the correlation between satisfaction of a product and positive perspective on consecutive purchases, the result of this study shows that the more satisfaction consumers feel after using a product, the more likely they are to purchase additional merchandises from the same company which manufactured the original product.

• Asia pacific journal of information systems
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• v.17 no.2
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• pp.97-122
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• 2007

Conventional networking and telecommunications infrastructure characterized by wires, fixed location, and inflexibility is giving way to mobile technologies. Numerous research reports point to the ultimate domination of wireless communication. With the increasing prevalence of advanced cell-phones, various mobile data services (hereafter MDS) are gaining popularity. Although cellular networks were originally introduced for voice communications, statistics indicate that data services are replacing the matured voice service as the growth engine for telecom service providers. For example, SK Telecom, the Korea's largest mobile service provider, reported that 25.6% of revenue and 28.5% of profit came from MDS in 2006 and the share is growing. Statistics also indicate that, in 2006, the average revenue per user (ARPU) for voice didn't change but MDS grew seven percents from the previous year, further highlighting its growth potential. MDS is defined "as an assortment of digital data services that can be accessed using a mobile device over a wide geographic area." A variety of MDS have been deployed, with a few reaching the status of killer applications. Many of them need to access the Internet through the cellular-phone infrastructure. In the past, when the cellular network didn't have acceptable bandwidth for data services, SMS (short messaging service) dominated MDS. Now, Internet-ready, next-generation cell-phones are driving rich digital data services into the fabric of everyday life, These include news on various topics, Internet search, mapping and location-based information, mobile banking and gaming, downloading (i.e., screen savers), multimedia streaming, and various communication services (i.e., email, short messaging, messenger, and chaffing). The huge economic stake MDS has on its stakeholders warrants focused research to understand associated dynamics behind its adoption. Lyytinen and Yoo(2002) pointed out the limitation of traditional adoption models in explaining the rapid diffusion of innovations such as P2P or mobile services. Also, despite the increasing popularity of MDS, unexpected drop in its usage is observed among some people. Intrigued by these observations, an exploratory study was conducted to examine decision factors of MDS usage. Data analysis revealed that the increase and decrease of MDS use was influenced by different forces. The findings of the exploratory study triggered our confirmatory research effort to validate the uni-directionality of studied factors in affecting MDS usage. This differs from extant studies of IS/IT adoption that are largely grounded on the assumption of bi-directionality of explanatory variables in determining the level of dependent variables (i.e., user satisfaction, service usage). The research goal is, therefore, to examine if increase and decrease in the usage of MDS are explained by two separate groups of variables pertaining to information quality and system quality. For this, we investigate following research questions: (1) Does the information quality of MDS increase service usage?; (2) Does the system quality of MDS decrease service usage?; and (3) Does user motivation for subscribing MDS moderate the effect information and system quality have on service usage? The research questions and subsequent analysis are grounded on the two factor theory pioneered by Hertzberg et al(1959). To answer the research questions, in the first, an exploratory study based on 378 survey responses was conducted to learn about important decision factors of MDS usage. It revealed discrepancy between the influencing forces of usage increase and those of usage decrease. Based on the findings from the exploratory study and the two-factor theory, we postulated information quality as the motivator and system quality as the de-motivator (or hygiene) of MDS. Then, a confirmative study was undertaken on their respective role in encouraging and discouraging the usage of mobile data service.

• Journal of Intelligence and Information Systems
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• v.22 no.4
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• pp.157-176
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• 2016

For a long time, mobile phone had a sole function of communication. Recently however, abrupt innovations in technology allowed extension of the sphere in mobile phone activities. Development of technology enabled realization of almost computer-like environment even on a very small device. Such advancement yielded several forms of new high-tech devices such as smartphone and tablet PC, which quickly proliferated. Simultaneously with the diffusion of the mobile devices, mobile applications for those devices also prospered and soon became deeply penetrated in consumers' daily lives. Numerous mobile applications have been released in app stores yielding trillions of cumulative downloads. However, a big majority of the applications are disregarded from consumers. Even after the applications are purchased, they do not survive long in consumers' mobile devices and are soon abandoned. Nevertheless, it is imperative for both app developers and app-store operators to understand consumer behaviors and to develop marketing strategies aiming to make sustainable business by first increasing sales of mobile applications and by also designing surviving strategy for applications. Therefore, this research analyzes consumers' mobile application usage behavior in a frame of substitution/supplementary of application categories and several explanatory variables. Considering that consumers of mobile devices use multiple apps simultaneously, this research adopts multivariate probit models to explain mobile application usage behavior and to derive correlation between categories of applications for observing substitution/supplementary of application use. The research adopts several explanatory variables including sociodemographic data, user experiences of purchased applications that reflect future purchasing behavior of paid applications as well as consumer attitudes toward marketing efforts, variables representing consumer attitudes toward rating of the app and those representing consumer attitudes toward app-store promotion efforts (i.e., top developer badge and editor's choice badge). Results of this study can be explained in hedonic and utilitarian framework. Consumers who use hedonic applications, such as those of game and entertainment-related, are of young age with low education level. However, consumers who are old and have received higher education level prefer utilitarian application category such as life, information etc. There are disputable arguments over whether the users of SNS are hedonic or utilitarian. In our results, consumers who are younger and those with higher education level prefer using SNS category applications, which is in a middle of utilitarian and hedonic results. Also, applications that are directly related to tangible assets, such as banking, stock and mobile shopping, are only negatively related to experience of purchasing of paid app, meaning that consumers who put weights on tangible assets do not prefer buying paid application. Regarding categories, most correlations among categories are significantly positive. This is because someone who spend more time on mobile devices tends to use more applications. Game and entertainment category shows significant and positive correlation; however, there exists significantly negative correlation between game and information, as well as game and e-commerce categories of applications. Meanwhile, categories of game and SNS as well as game and finance have shown no significant correlations. This result clearly shows that mobile application usage behavior is quite clearly distinguishable - that the purpose of using mobile devices are polarized into utilitarian and hedonic purpose. This research proves several arguments that can only be explained by second-hand real data, not by survey data, and offers behavioral explanations of mobile application usage in consumers' perspectives. This research also shows substitution/supplementary patterns of consumer application usage, which then explain consumers' mobile application usage behaviors. However, this research has limitations in some points. Classification of categories itself is disputable, for classification is diverged among several studies. Therefore, there is a possibility of change in results depending on the classification. Lastly, although the data are collected in an individual application level, we reduce its observation into an individual level. Further research will be done to resolve these limitations.

• Journal of Gifted/Talented Education
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• v.21 no.1
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• pp.57-81
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• 2011

The purpose of this study was to explore the quality of life of musically talented students as measured by their external experiences (e.g., activities, companions) and internal experiences (e.g., flow, emotion). The participants in this study were 33 musically talented students (10 males, 23 females) aged 13 to 19. Study data were collected for 7 consecutive days using the Experience Sampling Method (ESM), which employs a cellular-phone as a signaling device. The results were as follows: First, in response to the 1625 random signals, musically talented students reported that 40.9% of their time was spent on productive activities. An additional 33.4% of time was used for maintenance activities and the rest of their time was spent on leisure/social activities. Also, musically talented students reported that 48.5% of their time was spent alone. When they were alone, they spent a lot of time engaging in productive activities (44.3%). Second, in order to measure the flow of their life, two methods were used. One used a 4-channel flow model (i.e. apathy, boredom, flow, anxiety) and the other used 8 dimensions and conditions of the flow experience (i.e. concentration, self-consciousness disappears, action and awareness merge, distorted sense of time, freedom from worry about failure, clear goals, immediate feedback, balance between challenges and skills). According to the former, when engaged in music-related activities, musically talented students usually reported flow (54.0%), while they felt apathy (41.3%) for daily routines activities. According to the latter method, musically talented students experienced flow for most productive activities, while they experienced flow least for maintenance activities. Emotional variables of ESF are comprised of 10 semantic scales (i.e. happy-sad, strong-weak, active-passive, sociablelonely, proud-ashamed, involved-detached, excited-bored, clear-confused, relaxed-worried, cooperative-competitive). Musically talented students reported experiencing the most positive emotion for social activities and experiencing the most negative emotion for maintenance activities. Results of this study assert that musically talented students had to trade off immediate enjoyment for developing their special gifts. They could not afford as much time for socializing with friends, and they had to spend more time alone compared to their peers without such gifts. Consequently, they were found to deprive themselves of the spontaneous good times that teenagers usually thrive on. They were helped in this respect by their autotelic personality traits, especially their strong need for achievement and endurance. The downside, however, is that the moment-to-moment quality of their moods suffered. The argument concerning musically talented students applies for all adolescents. The choices that talented students must make between immediate gratification and long-term development, and between solitude and companionship, are the same choices every young person must make, regardless of her or his level of talent. All of us have gifts that are potentially useful and worthy of being appreciated. But to develop these latent talents we must cultivate them, and this takes time and the investment of mental energy. The lifestyle that musically talented students develop can show us some of the choices all of us must make in order to cultivate our gifts.