• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.1
• /
• pp.308-324
• /
• 2018

HTTP adaptive streaming (HAS) is a promising technology for delivering video content over the Internet. HAS-based video streaming solutions rely on bandwidth estimation to select the appropriate video bitrate. Video streaming solutions that consider network conditions provide users with seamless video playback. However, when multiple clients compete for a common bottleneck link, conventional bandwidth estimation schemes that consider only one client overestimate the network bandwidth due to the ON-OFF traffic pattern. The bandwidth overestimation can cause Quality of Experience (QoE) degradation, such as unnecessary changes in video quality, and unfairness of video quality. In this paper, we propose a client-side bandwidth estimation scheme to obtain a better QoE of HAS in the multiple-client environment. The proposed scheme differentiates the client buffer status according to the buffer occupancy, and then estimates the available network bandwidth based on the buffer status and segment throughput. We evaluate the performance of HAS implemented in the ns-3 network simulator. Simulation results show that compared with the conventional schemes, the proposed scheme can enhance the QoE.

• Journal of Korea Society of Industrial Information Systems
• /
• v.13 no.5
• /
• pp.44-54
• /
• 2008

The objective of this research is to develop a measurement instrument for service recovery quality in the Internet commerce setting. To this same end, Parasuraman et al.(2005) have devised a scale called E-RecS-QUAL, which we revised and supplemented to develop another instrument named eSR-Q. To guarantee its reliability and validity, this instrument went through the refinement and validation processes for internal consistency and construct validity in terms of convergent, discriminant, and nomological validity. Our final scale consists of four dimensions including responsiveness, compensation, contact, and apologies altogether with fourteen measures. Overall, this research deals with the related research background, the scale development and validation processes, its limitations, and future research directions.

• Journal of Korea Water Resources Association
• /
• v.30 no.4
• /
• pp.411-420
• /
• 1997

QUAL2E-AFOSM model is developed to forecast the water quality by reliability analysis in the Nakdong River. A varied-flow analysis is performed for the reach of Waegwan to Mulgeum to estimate hydraulic parameters. An optimization technique by BFGS method is applied to determine the optimum reaction parameters and calibrations and verifications are performed based on these parameters. A reliability analysis for the stochastic analysis in a river is studied using the AFOSM method. The variations of water quality and discharge in the headwater, tributaries, and reaction coefficients are considered. Risks of violating existing water quality standards at several loactions in the Nakdong River are computed by using the QUAL2E-AFOSM method. The computed results computed by QUAL2E-AFOSM model agree with those of the Monte-Carlo method in QUAL2EU model.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.219-221
• /
• 2017

Recently, MOOC (Massive Open Online Course), which has the characteristics of open content, has been changing the paradigm of university education as it is being serviced by various universities. In addition, MOOC based e-learning service has been developed into various types. The quality management of MOOC-based e-learning services has been studied on the general factors provided by MOOC regardless of MOOC type so far. In this study, we propose a method to improve the quality management of MOOC - based e - learning service by analyzing the factors affecting the quality of e - learning service by MOOC type.

• The Journal of Society for e-Business Studies
• /
• v.4 no.3
• /
• pp.77-94
• /
• 1999

The Electronic Commerce is expected as one of the most prospective industries in the 21th century, This research performed a survey and analysis is based on the results of the service quality model and previous research of the service quality in MIS. Service quality, one instrument developed by the marketing area, is provided as a possible measure of internet shopping mall, Service quality measures five service dimensions of tangible, reliability, responsiveness, assurance and empathy. The main purposes of this study are to develop an exploratory model based on service quality that can explain the factors of customer's perceived service quality and investigate how these factors are related to consumer satisfaction. The results of this survey are summarized as follows: (1) Reliability and responsiveness of internet shopping mall are evaluated as very important factors, (2) Service quality is an antecedent of consumer satisfaction, (3) Consumer satisfaction has a significant effect on purchase intentions.

• Journal of Korean Academy of Nursing
• /
• v.32 no.4
• /
• pp.539-549
• /
• 2002

This study was undertaken to examine the degree of quality of life and to analyze the factors affecting those quality of life in middle-aged men. Method: The subjects of this study were 208 men aged by 35-55 from 3 business enterprises located in Seoul and Incheon. Data collection was conducted through the use of 5 questionnaire. Result: There were significant differences in the quality of life according to marital status, religion, educational level, number of children and total house income. A positive correlation was found between quality of life and all independent variables i.e., health promoting behaviors, health perception, social support, self-esteem and self-efficacy. Stepwise Multiple Regression Analysis revealed that the most powerful predictor was self-esteem. Self- esteem, health perception, health promoting behaviors, marriage, and social support accounted for 65% of the variance in quality of life in middle-aged men. Conclusion: All independent variables i.e., health promoting behaviors, health perception, social support, self-esteem and self-efficacy were related with quality of life in middle-aged men. Therefore it is necessary to develop the nursing intervention with these variables to increase the quality of life for middle-aged men.

• Informatization Policy
• /
• v.18 no.2
• /
• pp.49-71
• /
• 2011

This study aims at finding what factors influence trust in e-government and how trust in e-government and satisfaction with e-government services affect trust in government. Despite of the importance of trust in e-government, there has not been sufficient research. Giving light on the factors of affecting trust in e-government is of academic significance. Therefore, the purpose of this study is to explore the nature, driving forces and consequences of citizens'trust in e-government and in government. The empirical results indicated that temporal embeddedness, network embeddedness, information provision quality, information security quality and e-participation quality affect satisfaction with e-government services and trust in e-government. Also, satisfaction with e-government services and trust in e-government influence trust in government, and satisfaction with e-government services affect trust in e-government.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2007.04a
• /
• pp.135-138
• /
• 2007

In this Paper, we try to define Quality for understanding Quality Concepts. There are many definition of Quality by many scholars. We try to find modern Quality condetion, special 21C, Also Nowadays we introduce variously Quality Movement.

• The Journal of the Korea Contents Association
• /
• v.5 no.5
• /
• pp.316-324
• /
• 2005

e-Learning has been mushrooming with wide range of teaming groups from pedagogy to andragogy As e-teaming opportunities increase, many people raise question about whether e-teaming show positive teaming effects. The related research emphasized that e-learning would be a failure in terms of understanding of e-Learners and activating intuitive teaming activities from learner's long-term memory span. The e-teaming strategies based on the traditional classroom and resulted boring and ineffective teaming outcomes, should be changed to provide authentic and effective teaming results. This paper analyzed that how learners have received e-Learning for the last few years from the research and explained what could be the failing aspects in e-Learning. To be successful, e-loaming should consider the e-learner's individualized teaming style and thinking patterns. When considering of various e-Learning components, the quality of e-teaming should not be focused on any specific single factor, but develop every individual factor to be integrated into high level of quality. In conclusion, this paper suggest that it is needed new understandings of e-Loaming and e-Learner. Also the e-Learning strategies should be examined throughly whether they are on the side of learners and realized how they learn from e-Learning. Finally, we should add enormous imagination into e-loaming for next generation because new generation's teaming patterns significantly differ from their parent's generation.

• KIISE Transactions on Computing Practices
• /
• v.22 no.7
• /
• pp.310-314
• /
• 2016

Currently, several research studies are looking to improve the quality of DASH (Dynamic Adaptive Streaming over HTTP) based live streaming services. However, conventional DASH based streaming schemes cannot provide seamless playback while maintaining the low buffering and it adversely affects the QoE (Quality of Experience). To address this problem, we propose the QoE driven segment scheduling scheme. The proposed scheme adaptively schedules the segment request message according to the time and variation of segment fetching. Simulation results indicate that the proposed scheme improves the QoE of live streaming service by maintaining the low buffering delay and reducing the buffer underflow events.