• Journal of Institute of Control, Robotics and Systems
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• v.13 no.12
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• pp.1252-1256
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• 2007

U-learning (ubiquitous learning) systems, which deliver learning materials anytime and anywhere, allow learners to watch live lectures on PDAs, tablet PCs and notebook computers via broadband and wireless Internet. These systems have various problems; first, terminal devices are expensive, and it is difficult to maintain their efficiencies. Secondly, Internet does not guarantee quality of service (QoS), and in general it does not provide real-time services. Finally, the security of these systems is weaker in a local network than in an external network. The USB-based terminal system based on the OSGi service platform was designed as a ubiquitous system, in order to solve those problems. The USB terminals, used in this system, are inexpensive, and it is easy to maintain their performances. Also, this system solves the problems of security in a local network and provides guaranteed QoS. To accomplish this, the number of USB terminals connected to the system has to be limited according to the formula proposed in our paper. This system uses the OSGi specification as a middleware. It supports the discovery mechanism of the USB terminals, maintenance and administration of the system. Finally, this paper shows a driver's license testing system as an example u-learning application1.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.375-378
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• 2009

DDoS attacks make people can't using normal internet service, because DDoS attacks cause exhaustion of network bandwidth or exhaustion of computer system resources by using many personal computers or servers which already infected computer virus from hackers. Recent DDoS attacks attack government brach, financial institution, even IT security company. IT security companies make Anti-DDoS product for defense from DDoS attack. But, There is no standard for BMT of Anti-DDoS product. In this dissertation, Anti-DDoS product quality characteristics of the survey analysis to evaluate them by comparing the assessment items were derived.

• Journal of Service Research and Studies
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• v.7 no.2
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• pp.17-41
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• 2017

The purpose of this research is to investigate the factors that impact customer satisfaction and loyalty in mobile payment services. Specifically, this research (1) studies the influence of company reputation on customer satisfaction and loyalty, (2) examines service quality dimensions that increase customer satisfaction, and (3) assesses switching barriers as moderators in influencing customer loyalty. Findings of this empirical research reconfirm the point of view that company reputation, service quality, and switching barriers are crucial for customer satisfaction in mobile payment services. The research methodologies that were used to verify the hypothesis in this study included customized surveys and structural equation modeling. The results demonstrated that company reputation significantly affects customer satisfaction and loyalty. Additionally, the results indicated that only two of the five total service qualities, ease of use and the security/privacy qualities, have positive influences on customer satisfaction. Customer satisfaction has also proven to be a significant influence on loyalty. Lastly, the results showed that among the factors of switching barriers, the factors of lost performance costs, sunk costs, setup costs, the attractiveness of alternatives, and service recovery have moderating effects on the relationships between customer satisfaction and loyalty. Base on the results, this research recommends that firms aim at devising integrated strategies that make switching barriers act as complements to customer satisfaction.

• Korean Security Journal
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• no.29
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• pp.35-57
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• 2011

While demands on private securities have been increase, expectations on the service quality as compensation for the investment expensive is also rising. However, private security services are in situations of not satisfying various customer's needs owing to insufficient special manpower, capital, and skills in spite of expected high-quality services toward customers. Therefore, this study aims to find out the causality between private security enterprises and relationship characteristics, purchasing behaviors of customers, and then searching for a marketing strategy that can provide best services to the enterprises that are confronting to limitless competitive systems by grasping customer's needs and necessities. For achieving this goal, the study objected to shop employees using private security enterprises after diving Cheonan City of South Chungcheong Province into South, East and East, West, and then collected 236 persons by using the convenience sampling. Regarding to research tools, this study used questionnaire having been recomposed based on previous researches home and abroad, and frequency analysis, reliability analysis, factor analysis, correlation analysis, and regression analysis were carried out data was treated by treatments by using SPSS version 18.0 statistic package for treating the data. Through above research methods and procedures, results could be gotten same as followings. First, correlations between private security enterprise's relationship characteristics and purchasing behaviors showed positive (+) relations, and the latter was increased as much as relationship characteristics were high. Second, as the result of analyzing correlations between private security enterprise's relationship characteristics and purchasing behaviors, reputation, physical features, and communication affected influences to word of mouth activities. Third, reputation and communication affected to repeated purchasing behaviors as the result of analyzing private security's relationship characteristics and repeat purchasing behaviors.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.1398-1400
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• 2011

2000년 초에 PC간 인터넷을 통한 음성통화를 시작으로 최근에는 스마트폰의 전용 애플리케이션까지 VoIP 기반의 음성통화 서비스가 발전해왔다. 이에 따라, VoIP를 통한 외부 공격 및 침입에 대한 사례가 발생되고 이를 해결하기 위한 보안 소프트웨어들이 나오기 시작하였다. 일반적으로 VoIP기반의 소프트웨어에 대한 품질 기준은 사용자의 통화품질이 최우선 이었다. 하지만, GS시험.인증 과정을 통해 VoIP 보안 소프트웨어가 통화품질에는 직접적인 영향을 미치지는 않지만 전체 운영 시스템에 미치는 영향을 확인하고, 시험 중 발생한 문제에 대한 해결 방안 제시를 통해 VoIP의 품질을 향상시킬 수 있었다.

• Culinary science and hospitality research
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• v.10 no.1
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• pp.46-63
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• 2004

The service quality factors which causes an effect in restaurant selections appeared with gain and loss factors of essence and the customers. The restaurant recommendation factor was appeared with shedding of blood characteristics. The research which sees Korean-style food party's decision making is difficult with the plan of the security and loyalty of customers presented. The marketing strategy for the customer loyalty of Korean-style food party will be able to be overcome. The critical point of the research which sees for the security of the loyalty customer selects a target market, and the strategy which invades intensively is necessary. The Korean-style food party decision may cause the customer fractionation anger which follows in market fractionation anger. It does not become accomplished from the research which sees but with the critical point of research to appear, the research of creation of the loyalty customer who applies a market fractionation anger necessity will be becomes feed with hereafter research subject.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.132-140
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• 2021

Under the mobile ad-hoc network system, the main reason for causing congestion is because of the limited availability of resources. On the other hand, the standardised TCP based congestion controlling mechanism is unable to control and handle the major properties associated with the shared system of wireless channels. It creates an effect on the design associated with suitable protocols along with protocol stacks through the process of determining the mechanisms of congestion on a complete basis. Moreover, when bringing a comparison with standard TCP systems the major environment associated with mobile ad hoc network is regraded to be more problematic on a complete basis. On the other hand, an agent-based mobile technique for congestion is designed and developed for the part of avoiding any mode of congestion under the ad-hoc network systems.

• International Journal of Computer Science & Network Security
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• v.21 no.9
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• pp.261-266
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• 2021

The spread of cloud computing, digital computing, and the popular social media platforms have led to increased growth of data. That growth of data results in what is known as big data (BD), which seen as one of the most strategic resources. The analysis of these BD has allowed generating value from massive raw data that helps in making effective decisions and providing quality of service. With Vision 2030, Saudi Arabia seeks to invest in BD technologies, but many challenges and barriers have led to delays in adopting BD. This research paper aims to search in the state of Big Data Analytics (BDA) in Saudi higher education sector, identify the barriers by reviewing the literature, and then to apply the design-reality gap model to assess these barriers that prevent effective use of big data and highlights priority areas for action to accelerate the application of BD to comply with Vision 2030.

• International Journal of Computer Science & Network Security
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• v.21 no.2
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• pp.221-228
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• 2021

Recent improvements on the quality, fidelity and availability of biometric data have led to effective human physical activity detection (HPAD) in real time which adds significant value to applications such as human behavior identification, healthcare monitoring, and user authentication. Current approaches usually use machine-learning techniques for human physical activity recognition based on the data collected from wearable accelerometer sensor from a single wearable smart device on the user. However, collecting data from a single wearable smart device may not provide the complete user activity data as it is usually attached to only single part of the user's body. In addition, in case of the absence of the single sensor, then no data can be collected. Hence, in this paper, a continuous HPAD will be presented to effectively perform user activity detection with mobile service infrastructure using multiple wearable smart devices, namely smartphone and smartwatch placed in various locations on user's body for more accurate HPAD. A case study on a comprehensive dataset of classified human physical activities with our HAPD approach shows substantial improvement in HPAD accuracy.

• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.70-76
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• 1999

In this paper, a mixed-integer programming approach is presented for adjusting the voltage profiles in a power system. The advent of large-scaled system makes the reactive power and voltage problem-an attempt to achieve an overall improvement of system security, service quality and economy-more complex and seriously, Although the problem is originally a nonlinear optimization problem, it can be formulated as a mixed integer linear programming(MILP) problem without deteriorating of solution accuracy to a certain extent. The MILP code is developed by the branch and bound process search for the optimal solution. The variable for modeling transformer tap positions is handled as discrete one, and other variables continuous ones. Numerical data resulting from case study using a modified IEEE 30 bus system with outaged line show that the MILP can produce more reductions of magnitude in the operating cost. The convergence characteristics of the results are also presented and discussed.