• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.11
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• pp.5419-5436
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• 2016

Enhancing the performance of computing systems has been an important topic since the invention of computers. The leading-edge technologies of multicore and virtualization dramatically influence the development of current IT systems. We study performance attributes of response time (RT), throughput, efficiency, and scalability of a virtualized Web system running on a multicore server. We build virtual machines (VMs) for a Web application, and use distributed stress tests to measure RTs and throughputs under varied combinations of virtual cores (VCs) and VM instances. Their gains, efficiencies and scalabilities are also computed and compared. Our experimental and analytic results indicate: 1) A system can perform and scale much better by adopting multiple single-VC VMs than by single multiple-VC VM. 2) The system capacity gain is proportional to the number of VM instances run, but not proportional to the number of VCs allocated in a VM. 3) A system with more VMs or VCs has higher physical CPU utilization, but lower vCPU utilization. 4) The maximum throughput gain is less than VM or VC gain. 5) Per-core computing efficiency does not correlate to the quality of VCs or VMs employed. The outcomes can provide valuable guidelines for selecting instance types provided by public Cloud providers and load balancing planning for Web systems.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.432-434
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• 2003

This paper developed the web based power flow program for education. Since a lot of users can connect and implement the web based program, the only one computer can get much evaluation burden not to compute. Using the XML technology, which supports the distributed computing technology, we have developed the web-based power flow software and system that are distributed the above calculation burden to three computers: web server, database server, application server. Also, this software was developed to get the difference of number of iteration and evaluation speed as veil as the results of state variables for each node according to the each calculation method for power flow using the chart. Therefore, users can get the physical concept of power flow in addition to the difference among the evaluation methods for power flow. We have performed the case studies with IEEE 14 bus system using the developed software.

• Journal of the Korean Society of School Health
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• v.31 no.3
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• pp.196-202
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• 2018

Purpose: The purpose of this study was to analyze the relationship between physical activity and energy drinks consumption in Korean Adolescents. Methods: This study was a secondary data analysis using statistics from the 2017(13th) Korea Youth Risk Behavior Web-based Survey. The variables used in the study were physical activity, energy drinks consumption and socio-demographic characteristics such as gender, academic achievement, household economic status and weekly allowance. The data were analyzed by $x^2$ test and multinominal logistic regression and the results were presented in percentage. Results: As the number of days engaging in moderate and vigorous physical activities increased, the response that they consume energy drinks 'more than 5 times a week' also increased. The subjects who participated in a 'moderate' or 'high' level of moderate physical activity consumed 1.4 times more energy drinks than those who do not participate in physical activity. And the subjects who engaged in a 'low' or 'moderate' level of vigorous physical activity consumed about 1.3 times more energy drinks than those who don't work out. Conclusion: As the level and intensity of physical activity increased, the number and frequency of energy drinks consumption increased. The results of this study can be used as basic data for intervention programs to reduce energy drinks consumption and promote proper physical activity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.9
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• pp.1279-1292
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• 2022

This study proposes a non-contact input method based on face recognition and Pyautogui mouse control as a system that can help users who have difficulty using input devices such as conventional mouse due to physical discomfort. This study includes features that help web surfing more conveniently, especially screen zoom, scroll function, and also solves the problem of eye fatigue, which has been suggested as a limitation in existing non-contact input systems. In addition, various set values can be adjusted in consideration of individual physical differences and Internet usage habits. Furthermore, no high-performance CPU or GPU environment is required, and no separate tracker devices or high-performance cameras are required. Through these studies, we intended to contribute to the realization of barrier-free access by increasing the web accessibility of the disabled and the elderly who find it difficult to use web content.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.155-161
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• 2023

In this paper, we present a WebRTC-based emergency video call system structure that builds a service system in a constant monitoring environment to increase the usability and stability of elevator emergency call devices. The proposed system provides a smooth call environment between the emergency call system in the elevator and maintenance managers in case of an emergency, performs rapid response processing to elevator emergency calls through monitoring of the target elevator, and handles any emergency calls that may occur in the physical space of the elevator. The purpose is to build an environment that can implement low-latency, real-time video call services of voice and video by overcoming the physical constraints required for video calls. To this end, we have established a service environment based on OpenAPI, which is currently used in various fields and its performance has been proven, and provides video calls and emergency situation dissemination through rapid messaging by providing low-latency call quality. The presented system structure will be able to provide a basis for expanding various functions and constructing a reliable service environment and intelligent model for the elevator system through combination with the elevator control panel and various devices.

• Convergence Security Journal
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• v.23 no.5
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• pp.45-55
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• 2023

With the widespread use of digital devices, anonymous communication technologies such as the dark web and deep web are becoming increasingly popular for criminal activity. Because these technologies leave little local data on the device, they are difficult to track using conventional crime investigation techniques. The United States and the United Kingdom have enacted laws and developed systems to address this issue, but South Korea has not yet taken any significant steps. This paper proposes a new blockchain-based crime investigation method that uses physical memory data analysis to track the behavior of anonymous network users. The proposed method minimizes infringement of basic rights by only collecting physical memory data from the device of the suspected user and storing the tracking information on a blockchain, which is tamper-proof and transparent. The paper evaluates the effectiveness of the proposed method using a simulation environment and finds that it can track the behavior of dark website users with a residual rate of 77.2%.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.1
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• pp.85-91
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• 2007

Purpose : The purpose of this study is understanding of Rett Syndrome. Rett Syndrome is a common developmental - neurologic disorder that has been reported almost exclusively in female. Recently mutations in the gene encoding X-linked methyl-CpG binding protein 2 (MECP2) have been identified as the cause of Rett syndrome. Consistent with the diagnostic criteria, hand skills, verbal or non - verbal communication skills and common motor skills were lost during regression. Regression most commonly occurred between 12 and 18 months of age. Methods : This is a literature study with books, articles, web site for Rett syndrome international association. Results : There is a continuing need to further elucidate the pre- and post - regression features of Rett syndrome. Rett syndrome need to physical therapy, musical therapy, special education and medical interventions. Conclusion : There has not been therapeutic method to the root of Rett syndrome but our goal is relaxation of symptom and physical therapist's study of Rett syndrome.

• Journal of Intelligence and Information Systems
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• v.7 no.1
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• pp.97-121
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• 2001

Until now, we have believed that one of advantages of cyber market is that it can virtually display and sell goods because it does not necessary maintain expensive physical shops and inventories. But, in a highly competitive environment, business model that does away with goods in stock must be modified. As we know in the case of AMAZON, leading companies already consider merchandise management as a critical success factor in their business model. That is, a solution to compete against one's competitors in a highly competitive environment is merchandise management as in the traditional retail market. Cyber market has not only past sales data but also web log data before sales data that contains information of path that customer search and purchase on cyber market as compared with traditional retail market. So if we can correctly analyze the characteristics of before sales patterns using web log data, we can better prepare for the potential customers and effectively manage inventories and merchandises. We introduce a systematic analysis method to extract useful data for merchandise management - demand forecasting, evaluating & selecting - using web mining that is the application of data mining techniques to the World Wide Web. We use various techniques of web mining such as clustering, mining association rules, mining sequential patterns.

• Management & Information Systems Review
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• v.17
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• pp.243-261
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• 2005

A research model based on the concept of a strategic grid was developed to examine the relationship between the role of information system(IS) and organizational use of the web-based electronic commerce(EC) system to achieve business competitiveness. A survey questionnair was sent eletronically to 141 internet shopping malls which sell physical goods direct to an individual end consumer and 125 usable responses were abtained. The results indicated that firms with the strategic views of IS make more use of web-based EC system than firms with support views of IS to achieve their bossiness goals.

• Journal of Sensor Science and Technology
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• v.16 no.2
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• pp.110-114
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• 2007

In this paper we present 3-D Navigation View, a three-dimensional visualization of indoor environment which serves as an intuitive and unified user interface for our developed indoor location tracking system via Virtual Reality Modeling Language (VRML) in web environment. The extracted user's spatial information from indoor location tracking system was further processed to facilitate the location indication in virtual 3-D indoor environment based on his location in physical world. External Authoring Interface (EAI) provided by VRML enables the integration of interactive 3-D graphics into web and direct communication with the encapsulated Java applet to update position and viewpoint of user periodically in 3-D indoor environment. As any web browser with VRML viewer plug-in is able to run the platform independent 3-D Navigation View, specialized and expensive hardware or software can be disregarded.