• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.4B
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• pp.314-321
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• 2011

There have been considerable standardization works to measure subjective video quality. However, these standardization methods are based on the situation where they have original or reference video sequences, and measure the video quality by looking the sequence during short time duration, e.g. 10 seconds. Since people's TV watching time durations in IPTV services are very long (e.g. more than 30 minutes), the quality measurements by the standards are not practical. In this paper, we analyze the effect of video quality rating period to MOS (Mean Opinion Score), and suggest a proper rating duration of subjective video quality for IPTV services.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.5
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• pp.425-432
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• 2014

The Enhanced Distributed Channel Access (EDCA) function of IEEE 802.11e standard defines contention window (CW) for different Access Category (AC) limits to support Quality-of-Service (QoS). However, it have been remained the problem that the collision probability of transmission is increasing in congested network. Several different solutions have been proposed but the collision occurs among same priority queue within the same station to compete the channel access. This paper presents an APCA (Advanced Priority Collision Avoidance) algorithm for EDCA that increases the throughput in saturated situation. The proposed algorithm use reserved field's bits of FC(Frame Control) using IEEE 802.11e standard's RTS/CTS (Request to Send / Clear to Send) mechanism to avoid data collision. The simulation results show that the proposed algorithm improves the performance of EDCA in packet loss. Using Jain's fairness index formula, we also prove that the proposed APCA algorithm achieves the better fairness than EDCA method under network congested condition.

• The Journal of Society for e-Business Studies
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• v.16 no.4
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• pp.283-299
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• 2011

In this paper, we draw upon Task-Technology Fit theory to investigate the fit attributes which impacted on customer preference over three virtual shopping channels which included TV home shopping, Internet shopping, and broadband applications, i.e. IPTV. The fit attributes also reflected the product category contingency, which is classified based on the degree of quality assessing difficulty on the web, such as quasi-commodity, look and feel goods, and look and feel with variable quality goods. Using the collected survey data, we employed stepwise regression analysis to validate the fit attributes in the context of performing virtual shopping task via those three distinctive media technologies. Furthermore, through ANOVA test with Duncan statistics, we reported comparative intensity of the valid fit attributes across the product categories and distinct media technologies. The results validated four critical fit attributes and significant distinctions among product categories and three virtual shopping channels. The findings provide practical insights in distribution channel design exploiting digital convergence technologies.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.3_4
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• pp.402-411
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• 2002

The objective of this study was to investigate sensibility images of Korean traditional motifs cognized by college students in U.S.A. The subjects consisted of 217 male and 351 female undergraduate students. The experimental materials used in this study were 48 stimuli and questionnaires, composed of 7-point semantic differential scales of 15 bipolar adjectives. Twelve motifs selected from 3 groups of Korean motifs were used as motif stimuli. Twelve repeated patterns were constructed from them to be applied on a CAD-simulated dress. The data were analyzed by factor analysis, ANOVA, Duncan's multiple range test. The major finding were as follows: 1. Four dimensions were emerged accounting for the dimensional structure of the images of Korean traditional motifs. These dimensions were ‘quality’, ‘simplicity’, ‘cheerfulnees’, and ‘modernity’. Among them, ‘quality’and ‘simplicity’were the major dimensions. 2. Category, interpretation type, composition type, and application object had significant effects on the images of above-mentioned dimensions. The interpretation type had a significant effect on ‘quality’image, the composition type on ‘cheerful’image, and the application object on ‘modernity’image.

• Journal of Climate Change Research
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• v.8 no.3
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• pp.239-245
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• 2017

This study aimed to suggest priority for developing emission factor (EF) and to develop the methodology of quantitative assessment of EF in the forestry sector. Based on the stock-difference method, 17 kinds of EFs (27 EFs based on forest types) were required to calculate the carbon emission in the forestry sector. Priority for developing EFs followed the standards, which is a development plan by the government agency, importance of carbon stock for greenhouse gas, and EFs by the species. Currently, the most urgent development of EFs was carbon fraction in biomass and carbon stock in dead wood. Meanwhile, the quantitative assessment of EF consisted of 7 categories (5 categories of compulsory and 2 categories of quality evaluation) and 12 verification factors. Category in compulsory verification consisted of administrative document, determination methodology of emission factors, emission characteristic, accuracy of measurement and analysis, and data representative. Category in quality evaluation consisted of data management and uncertainty estimates. Based on the importance of factors in the verification process, each factor was scored separately, however, the score needs to be coordinated by the government agency. These results would help build a reliable and accurate greenhouse gas inventory report of Korea.

• Journal of Korean Biological Nursing Science
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• v.25 no.3
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• pp.172-182
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• 2023

Purpose: This study investigated the differences in physical function, self-efficacy (SE), and health-related quality of life (HRQoL) categorized by disease severity in community-dwelling patients with chronic obstructive pulmonary disease (COPD). Methods: This cross-sectional study included 182 patients with COPD selected from the pulmonology outpatient department of a tertiary hospital. Disease severity was measured using forced expiratory volume in 1 second (FEV1). Physical function, SE, and HRQoL were measured with the six-minute walking distance, Pulmonary Rehabilitation Adapted Index of Self-Efficacy (PRAISE), and St. George's Respiratory Questionnaire (SGRQ). Disease duration, FEV1, and 12-month history of exacerbations were obtained from medical records. Patients were categorized by Global Initiative for Chronic Obstructive Lung Disease (GOLD) category. Data were analyzed using the χ² test, and one-way ANOVA. Results: Most of the participants were male and nonsmokers. The disease duration was 10.76 ± 10.03 years, the mean FEV1% was 62.13 ± 22.80, and 70.3% of the participants were in GOLD category 2 (moderate) or milder. Half of the participants reported modified Medical Research Council scores ≥ 2. Patients in GOLD categories 1 and 3 (mild and severe) exhibited significantly higher PRAISE scores than those in the other groups (F = 8.23, p < .001). The total SGRQ scores were highest in GOLD 4 (very severe), indicating the lowest HRQoL. Significant differences were identified among GOLD 1, GOLD 2 and 3, and GOLD 4 (F = 9.92, p < .001). Conclusion: We identified potentially useful variables to comprehensively assess disease severity and tailor management strategies, including airflow limitation, and to determine the consequences of COPD from patients' perspectives.

• Journal of Intelligence and Information Systems
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• v.18 no.4
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• pp.1-17
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• 2012

Personalized smart devices such as smartphones and smart pads are widely used. Unlike traditional feature phones, theses smart devices allow users to choose a variety of functions, which support not only daily experiences but also business operations. Actually, there exist a huge number of applications accessible by smart device users in online and mobile application markets. Users can choose apps that fit their own tastes and needs, which is impossible for conventional phone users. With the increase in app demand, the tastes and needs of app users are becoming more diverse. To meet these requirements, numerous apps with diverse functions are being released on the market, which leads to fierce competition. Unlike offline markets, online markets have a limitation in that purchasing decisions should be made without experiencing the items. Therefore, online customers rely more on item-related information that can be seen on the item page in which online markets commonly provide details about each item. Customers can feel confident about the quality of an item through the online information and decide whether to purchase it. The same is true of online app markets. To win the sales competition against other apps that perform similar functions, app developers need to focus on writing app descriptions to attract the attention of customers. If we can measure the effect of app descriptions on sales without regard to the app's price and quality, app descriptions that facilitate the sale of apps can be identified. This study intends to provide such a quantitative result for app developers who want to promote the sales of their apps. For this purpose, we collected app details including the descriptions written in Korean from one of the largest app markets in Korea, and then extracted keywords from the descriptions. Next, the impact of the keywords on sales performance was measured through our econometric model. Through this analysis, we were able to analyze the impact of each keyword itself, apart from that of the design or quality. The keywords, comprised of the attribute and evaluation of each app, are extracted by a morpheme analyzer. Our model with the keywords as its input variables was established to analyze their impact on sales performance. A regression analysis was conducted for each category in which apps are included. This analysis was required because we found the keywords, which are emphasized in app descriptions, different category-by-category. The analysis conducted not only for free apps but also for paid apps showed which keywords have more impact on sales performance for each type of app. In the analysis of paid apps in the education category, keywords such as 'search+easy' and 'words+abundant' showed higher effectiveness. In the same category, free apps whose keywords emphasize the quality of apps showed higher sales performance. One interesting fact is that keywords describing not only the app but also the need for the app have asignificant impact. Language learning apps, regardless of whether they are sold free or paid, showed higher sales performance by including the keywords 'foreign language study+important'. This result shows that motivation for the purchase affected sales. While item reviews are widely researched in online markets, item descriptions are not very actively studied. In the case of the mobile app markets, newly introduced apps may not have many item reviews because of the low quantity sold. In such cases, item descriptions can be regarded more important when customers make a decision about purchasing items. This study is the first trial to quantitatively analyze the relationship between an item description and its impact on sales performance. The results show that our research framework successfully provides a list of the most effective sales key terms with the estimates of their effectiveness. Although this study is performed for a specified type of item (i.e., mobile apps), our model can be applied to almost all of the items traded in online markets.

• Asian Oncology Nursing
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• v.4 no.1
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• pp.71-81
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• 2004

The purpose of the study was to understand and explore the quality of life in cancer patients in the context of a Korean culture and society. Grounded theory method guided the data collection and analysis. A total of 10 cancer patients was selected by a theoretical sampling. The data were collected by an open question. All interviews were audio taped and transcribed verbatim. Constant comparison analysis was employed to analyze the data. As the results, eighty-five concepts and twelve categories were emerged, and "keeping well-being status" identified as a core category. Quality of life related categories derived from this study will academically contribute to the understanding and expansion of theoretical bases for quality of life of Korean cancer patients and to the contexts for the development of measurement of quality of life. Furthermore, they will function as the foundation of a intervention development for quality of life.

• Journal of Korean Society of Transportation
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• v.22 no.5
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• pp.35-45
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• 2004

This paper analyzes the differences in the service quality priorities of air cargo service providers and customers. After having identified what constitutes the decisive factors with regards to air cargo service quslity, research was carried out to evaluate the differences in the service quality priorities of air cargo service providers and customers. Moreover, this paper analyzes these differences by separating air cargo service providers into Korean and international air cargo service providers. In order to attain the objectives of this research, the air cargo service sectors were divided into three general categories: supply capability(H/W), service accountability, and competitiveness of service fees and management capability(S/W). The researchers then placed 6 different criteria into each service category, for a total of 18. The evaluation of the service quality priorities of air cargo service providers and customers revealed very little difference between these two groups. With regards to the service criteria found in each service category, our research found marked differences between the service quality priorities of providers and customers in only three of the 18 criteria. However, we found marked differences in service quality priorities in 7 of the 18 criteria when the air cargo service providers were divided into Korean and international air cargo providers. While domestic air cargo service providers evaluated management's capability to handle cargo accidents and incidents as the most important priority, international air cargo service providers placed the highest priority on the cargo rate system. The results of this research imply that in order to properly evaluate the differences between the service quality priorities of air cargo service providers and customers, the air cargo service providers itself should be separated between the Korean air cargo service providers and the foreign providers because of their respective inherent perception on service quality.

• Journal of Environmental Science International
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• v.7 no.3
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• pp.321-326
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• 1998

The water Quality and phytoplankton communities of the coastal waters of Inchon were Investigated 4 tomes from May, 1995 to January. 1996. The characteristic of the study was shallow muddy bottom onoronment with high SS concentration. The water qualities were belong to the category of I-grade in DO, II to III grade in COD and III-grade In Inorganic nutrients such as T-N and T-p. Total 136 species of shytoplankton were observed in thins study and species richness was on the decrease compared with the results of previous studies. The mean of phytoplankton species diversities was 1.93, decreased in recent years and the value in autumn was slightly higher than that in other seasons.