• Journal of Digital Convergence
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• v.12 no.6
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• pp.457-465
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• 2014

Purpose: The purpose of this study was to identify degree of quality of life and recovery of mental disorder, to determine the factors affecting the quality of life. Methods: The data were collected from May 20 to 27 2013. Data were collected by questionaire from 310 individuals with mental disorder. The instruments for this study were Happy-Quality of Life Scale(Happy-QoL), Recovery. The data were analyzed using descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, multiple linear regression with the SPSS/WIN 18.0 program. Results: The degree of quality of life and recovery of mental disorder were lower than in the middle. The significant factors influencing quality of life were recovery(${\beta}=.66$, p<.001) and average monthly household income(${\beta}=.09$, p=.039). Conclusion: It is necessary to develop the program that increasing the level of recovery and quality of life.

• Journal of Digital Convergence
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• v.14 no.11
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• pp.27-35
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• 2016

The study was conducted to identify related risk factor of elderly's suicidal ideation. This study used a cross-sectional design with secondary analysis of the $6^{th}$ 2013 Korea National Health and Nutrition Examination Survey (KNHANES). Data for 1,201 elderlies who aged over 65 years old from the KNHANES were included. Suicidal ideation, general characteristics, physical health, psychological health, EuroQoL, and health behavior were measured. Chi-square test, t-test, and multiple logistic regression were used to analyze this data through the SPSS win 22.0 program. In the results, 7.7% of the elderly had suicidal ideation. The odds ratios of suicidal ideation were significantly higher among those with restriction of activity (OR=1.31, CI=1.40~3.82), those with depression (OR=4.44, CI=1.66~7.40), and those with high levels of stress (OR=9.24, CI=3.48~24.5). Therefore, the activity level, depression level, and stress level need to be regularly assessed in order to prevent suicidal ideation among the elderly.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.345-353
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• 2021

Cloud computing represent a new era of computing that's forms through the combination of service-oriented architecture (SOA), Internet and grid computing with virtualization technology. Virtualization is a concept through which every cloud is enable to provide on-demand services to the users. Most IT service provider adopt cloud based services for their users to meet the high demand of computation, as it is most flexible, reliable and scalable technology. Energy based performance tradeoff become the main challenge in cloud computing, as its acceptance and popularity increases day by day. Cloud data centers required a huge amount of power supply to the virtualization of servers for maintain on- demand high computing. High power demand increase the energy cost of service providers as well as it also harm the environment through the emission of CO₂. An optimization of cloud computing based on energy-performance tradeoff is required to obtain the balance between energy saving and QoS (quality of services) policies of cloud. A study about power usage of resources in cloud data centers based on workload assign to them, says that an idle server consume near about 50% of its peak utilization power [1]. Therefore, more number of underutilized servers in any cloud data center is responsible to reduce the energy performance tradeoff. To handle this issue, a lots of research proposed as energy efficient algorithms for minimize the consumption of energy and also maintain the SLA (service level agreement) at a satisfactory level. VM (virtual machine) consolidation is one such technique that ensured about the balance of energy based SLA. In the scope of this paper, we explore reinforcement with fuzzy logic (RFL) for VM consolidation to achieve energy based SLA. In this proposed RFL based active VM consolidation, the primary objective is to manage physical server (PS) nodes in order to avoid over-utilized and under-utilized, and to optimize the placement of VMs. A dynamic threshold (based on RFL) is proposed for over-utilized PS detection. For over-utilized PS, a VM selection policy based on fuzzy logic is proposed, which selects VM for migration to maintain the balance of SLA. Additionally, it incorporate VM placement policy through categorization of non-overutilized servers as- balanced, under-utilized and critical. CloudSim toolkit is used to simulate the proposed work on real-world work load traces of CoMon Project define by PlanetLab. Simulation results shows that the proposed policies is most energy efficient compared to others in terms of reduction in both electricity usage and SLA violation.

• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.34-40
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• 2018

In this study, the optimal buffer size is calculated for seamless video playback on a mobile device. Buffer means the memory space for multimedia packet which arrives in mobile device for video play such as VOD service. If the buffer size is too large, latency time before video playback can be longer. However, if it is too short, playback service can be paused because of shortage of packets arrived. Hence, the optimal buffer size insures QoS of video playback on mobile devices. We model the process of buffering into a discret-time queueing model. Mean busy period length and mean waiting time of Geo/G/1 queue with N-policy is analyzed. After then, we uses the main performance measures to present numerical examples to decide the optimal buffer size on mobile devices. Our results enhance the user satisfaction by insuring the seamless playback and minimizing the initial delay time in VOD streaming process.

• Journal of the Korea Society of Computer and Information
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• v.12 no.4
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• pp.257-267
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• 2007

Bandwidth Trading(BT) represents a potential market with over 1 trillion USD across the world and high growth potential. BT is also likely to accelerate globalization of the telecommunications industry and massive restructuring driven by unbundling rush. However, systematic researches on BT remain at an infant stage. This study starts with structure analysis of the Internet industry, and discusses significance of Internet interconnection with respect to BT issues. We also describe the bandwidth commoditization trends and review technical requirements for effective Internet interconnection with BT capability. Taking a step further, this study explores the possibility of improving efficiency of network providers and increasing user convenience by developing an architectural prototype of Hub-&-Spoke interconnection model required to facilitate BT. The BT market provides an innovative base to ease rigidity of two-party contract and increase service efficiency. However, as fair, efficient operation by third party is required, this research finally proposes an exchanging hub named NIBX(New Internet Business eXchange).

• The KIPS Transactions:PartA
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• v.8A no.4
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• pp.287-292
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• 2001

Multimedia service systems should have efficient capacity to serve the growing clients and new data. In the general streaming services, users can endure the small amount of time delay at the beginning of service. But they want to have good quality of service. A streaming server tries to transfer video files to clients from a repository of files in real time. The server must guarantee concurrent and uninterrupted delivery of each video stream requested from clients. To achieve its purpose, many stream servers adopt multi-processors, sufficient memory, and RAID or SAN in their systems. In this paper, we propose a Linux-based parallel media streaming server. It is superior to the other systems in the storing structure, fault-tolerance, and service capacity. Since this system supports the web interlace, users can operate easily through the www. This system uses unique striping policy to distribute multimedia files into the parallel storage nodes. If a service request occurs, each storage node transmits striped files concurrently to the client. Its performance is better than the single media streaming service because of the parallel architecture.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.119-129
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• 2019

Although line production systems with finite buffers have been studied over several decades, except for some special cases there are no explicit expressions for system performances such as waiting times(or response time) and blocking probability. Recently, a max-plus algebraic approach for buffer-sharing systems with constant processing times was introduced and it can lead to analytic expressions for (higher) moment and tail probability of stationary waiting. Theoretically this approach can be applied to general processing times, but it cannot give a proper way for computing performance measures. To this end, in this study we developed simulation models using @RISK software and the expressions derived from max-plus algebra, and computed and compared blocking probability, waiting time (or response time) with respect to two blocking policies: communication(BBS: Blocking Before Service) and production(BAS: Blocking After Service). Moreover, an optimization problem which determines the minimum shared-buffer capacity satisfying a predetermined QoS(quality of service) is also considered.

• Korea Journal of Hospital Management
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• v.25 no.4
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• pp.29-37
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• 2020

Purposes: This study purposed to identify influence of postpartum care services on health-related quality of life in women after birth. Methodology: Korea Health Panel Survey 2009-2015 provided by the Korea Institute for Health and Social Affairs and National Health Insurance Service was used for the analysis. The health-related quality of life evaluate as a EuroQoL-5D(EQ-5D-3L, used the weight of the CDC) was used as dependent variables. Postpartum care services was used as independent variable. Demographic factors(education, economic activity, region, house income), health related variable(presence of chronic disease, self-rated health), birth related variable(birth-related problem, childbirth, pregnancy of advanced maternal age) used as covariates. Regression analysis was used. Findings: The rate of use of postpartum care services is increasing year by year. Postpartum care services and self-rated health positively influence on the health-related quality of life in women after birth and chronic disease and birth-related problem negatively influence on. Practical Implications: Therefore, it is necessary that the government's policy of the postpartum care service be expanded and systematized to increase accessibility on. There are rare studies on the health-related quality of life of women after childbirth, adjusted for birth-related variables. So this study has significance.

• Journal of Digital Convergence
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• v.20 no.4
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• pp.459-468
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• 2022

In medical area, very high resolution images, which is loss sensitive data, are used. Therefore, the use of optical internet with high bandwidth and the transmission of high realiability is required. However, according to the nature of the Internet, various data use the same bandwidth and a new scheme is needed to differentiate effectively these data. In order to achieve the differentiation, optical delay line buffers are used. However, these buffers is constructed based on some optimal values such as the average offered load, measured data burst length, and basic delay unit. Once the buffers are installed, they are impossible to reinstall new buffers. So, the scheme changing burst length dynamically was considered. However, this method is highly unstable. Therefore, in this article, in order to guarantee the stable operation of the scheme, the analysis of operation conditions is performed. With the analysis together with the scheme, high resolution medical data with the higher class can transmit stably without loss.

• Journal of Digital Convergence
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• v.20 no.3
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• pp.377-388
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• 2022

Various researches are actively studied to satisfy exponentially increasing the usage of the Internet as well as the diverse service demands. Especially the Optical Internet that delivers several Tbps through a single optical fiber requires the intelligence to satisfy the various types of survivability requirements. In the paper, a novel recovery scheme that satisfies the various restoration demands in IP over WDM networks is proposed. The scheme classifies the restoration services into three classes and applies dedicated protection and shared restoration scheme with different priorities for each class. Also, a configuration scheme for information database to support the scheme is proposed. This scheme satisfies the different degree of restoration demands in terms of restoration time, blocking rate and resource usage. With the scheme, medical data can be transmitted without loss.