• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.2
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• pp.62-67
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• 2003

This paper deals with a First-Come, First-Served queueing model to analyze the behavior of heterogeneous finite source system with a single server Each sources and the processor are assumed to operate in independently Markovian environments, respectively. Each request is characterized by its own exponentially distributed source and service time with parameter depending on the state of the corresponding environment, that is, the arrival and service rates are subject to random fluctuations. Our aim is to get the usual stationary performance measures of the system, such as, utilizations, mean number of requests staying at the server, mean queue lengths, average waiting and sojourn times. In the case of fast arrivals or fast service asymptotic methods can be applied. In the intermediate situations stochastic simulation Is used. As applications of this model some problems in the field of telecommunications are treated.

• Journal of IKEEE
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• v.18 no.1
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• pp.146-151
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• 2014

The Smart Grid provide a lot of additional service between ICT(Information Communication Technology) and fusion service. The smart grid using various protocol need to use independent middleware system for exchanging information data. The application system of Smart Grid is exchanging information on the almost All-IP system. The current All-IP middleware system consist of SOAP and RESTful. This paper analysis SOAP and RESTful. This result make use of building Smart Grid System.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.9B
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• pp.783-792
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• 2003

We consider a finite-buffer discrete-time queueing system with fixed-size bulk-service discipline: Geo/ $G^{B}$1/K＋B. The main purpose of this paper is to present a performance analysis of this system that has a wide range of applications in Asynchronous Transfer Mode (ATM) and other related telecommunication systems. For this purpose, we first derive the departure-epoch probabilities based on the embedded Markov chain method. Next, based on simple rate in and rate out argument, we present stable relationships for the steady-state probabilities of the queue length at different epochs: departure, random, and arrival. Finally, based on these relationships, we present various useful performance measures of interest such as the moments of number of packets in the system at three different epochs and the loss probability. The numerical results are presented for a deterministic service-time distribution - a case that has gained importance in recent years.s.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.300-302
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• 2006

Middleware offers function that user application program can transmit data independently of network device. Connection management about network connection of module is important for normal service of module base personal robot. Unpredictable network disconnection is influenced to whole robot performance in module base personal robot. For this, Middleware must be offer two important function. The first is function of error detection and reporting about abnormal network disconnection. Therefore, middleware need method for network error detection and module management to consider special quality that each network device has. The second is the function recovering that makes the regular service possible. When the module closed from connection reconnects, as this service reports connection state of the corresponding module, the personal robot resumes the existing service. In this paper proposed method of network connection management for to support fault tolerant about network error of network module based personal robot.

• Journal of Korea Society of Digital Industry and Information Management
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• v.12 no.1
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• pp.13-26
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• 2016

Service and technology for the future hyper-connected society, which is every information receive through the mobile internet, will be an Internet of Things. Thus, it is mandatory to derive key standardization work item and establish strategy for the global business with the standardization of device and service platform by the application service. In this study, by analyzing the domestic and international market trends, state of technical development, and standardization of technology, we identified the open platform is the stepping stone for achieving the goal which is establishing the virtuous circulation of IoT ecosystem. Also, we defined emphasized key standardization work item for achieving the open platform are network, server, access authentication, billing system, and software platform. After that, we proposed future strategy direction of standardization. This research could be contribute to the IoT service diffusion by realizing IP communication among low power wireless terminals and implementing light-weight standard internet protocol.

• Research in Mathematical Education
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• v.18 no.2
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• pp.129-148
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• 2014

In this study, we examined the relationships among years of teaching experience, professional rank, number of courses taken, and knowledge of algebra for teaching (KAT). 338 in-service and 376 pre-service secondary mathematics teachers in China completed a KAT questionnaire. Various statistical techniques were employed to examine these relationships. The pre-service participants teachers performed statistically significantly higher in advanced mathematics knowledge than their in-service counterparts. Among the inservice teachers, senior teachers had scored higher in school mathematics and teaching mathematics, compared with junior teachers. Yet participants' advanced mathematics knowledge decreased as their professional rank advanced or their teaching experience increased. The number of courses taken has significantly positive correlation with school mathematics knowledge and advanced mathematics knowledge. The implications of these findings for mathematics teacher education are discussed.

• Journal of information and communication convergence engineering
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• v.9 no.4
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• pp.353-357
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• 2011

U.S. Obama government is submit a motion to consider cyber attacks on State as a war. 7.7DDoS attack in Korea in 2009 and 3.4 DDoS attacks 2011, the country can be considered about cyber attacks. China hackers access a third country, bypassing South Korea IP by hacking the e-commerce sites with fake account, that incident was damaging finance. In this paper, for WiBro service, DDoS attacks, hackers, security incidents and vulnerabilities to the analysis. From hacker's attack, WiBro service's prognostic relevance by analyzing symptoms and attacks, in real time, Divide Red, Orange, Yellow, Green belonging to the risk rating. For hackers to create a blacklist, to defend against attacks in real-time air-conditioning system is the study of security. WiBro networks for incident tracking and detection after the packets through the national incident response should contribute to the development of technology.

• Journal of the Korean Institute of Navigation
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• v.24 no.4
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• pp.299-312
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• 2000

Because shore(ship) to ship(shore) communication service via INMARSAT pay expensive cost, satellite service typically use two stage service that land users dial up LES(Land Earth Station) for sending or receiving message. In order to send and receive message, land users must maintain online state with LES on dedicated line. Also, two stage INMARSAT communication service must consume long time that processes step by step. In case of large company, they have own communication system, but small companys communicate simple messages with only telex. This paper describes the design and implementation of an integrated communication services via INMARSAT-C. This system uses inexpensive INMARSAT-C for transmission between ship and land. Because this system provides web and E-Mail interface, users send and receive messages easily and quickly. This system provides most users with inexpensive and easy communication facilities between ship and land.

• The Journal of Korean Medical History
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• v.34 no.2
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• pp.79-87
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• 2021

The civil service examination system is an important part of the history of education in East Asia. In China, the civil service examination system lasted for almost 1,300 years. Through this, each dynasty was able to prevent the concentration of power to the hereditary nobles and to give competent talents an opportunity to rise to an important position in the state. In terms of medical education, in China, doctors have already been selected through tests since the Song Dynasty. However, the actual cases of medical tests currently remaining in each dynasty are very rare. This paper, firstly, examines the implementation method of the medical test during the Qing Dynasty and examines how it influenced the merit rating. and secondly, this paper examines the actual cases of the remaining Qing medical exam questions, in terms of content, related to the medical text "Uijonggeumgam (醫宗金鑑)" and was influenced by the style of the civil service examination at that time.

• International Journal of Contents
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• v.14 no.4
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• pp.30-38
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• 2018

Recently, HTTP Adaptive Streaming(HAS), a video streaming service over the HTTP based web platform has become common. The use of HAS service in mobile communication devices such as mobile phones and tablet PCs is rapidly expanding. This paper addresses ways to improve the quality of HAS service by enhancing the terms of viewer satisfaction. HAS systems have several internal operational processes, which can affect viewer satisfaction. Such processes include, the quality determination for the next video chunk, the TCP connections-setup procedure and the congestion control operation of the TCP. This paper proposes a transmission scheme to improve the HAS quality services over mobile web. The proposed scheme takes into consideration the past implicit communication state of the receiver's playback buffer occupancy. The results of these experiments indicate that the proposed scheme can improve the quality of HAS service from the mobile viewer's point of view.