• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.157-164
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• 2012

This paper introduces an implementation of SVC player which runs on Android platform and can play SVC video stream on line from SVC video server. SVC(Scalable Video Coding) is a scalable video encoding technique which supports three scalability such as temporal scalability, spatial scalability, and quality scalability. To implement the SVC player on Android, we implemented a SVC decoder using JSVM open source written in C/C++ as a native part on Android and developed Android UI in Java. Also we built an SVC encoding system off line and an SVC streaming server to conduct on-line SVC streaming experiments. Finally, after we installed the SVC player developed in this paper on Motoroi mobile phone, we evaluated and analyzed on-line streaming performance of the SVC player. The result showed that the player worked well and it had no jitter in streaming with the size of QCIF and 10fps from a fully encoded SVC video source.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.55-60
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• 2013

Smart client is a term describing an application environment which delivers applications over a web HTTP connection and does not require installation and/or updates. The term "Smart Client" is meant to refer to simultaneously capturing the benefits of a "thin client" (zero-install, auto-update) and a "fat client" (high performance, high productivity). A "Smart Client" application can be created in several very different technologies. Over the past few years, ITS has started to move towards smart clients, also called rich clients. The trend is a move from traditional client/server architecture to a Web-based model. More similar to a fat client vs. a thin client, smart clients are Internet-connected devices that allows a user's local applications to interact with server-based applications through the use of Web services. Smart Client applications in BIT bridge the gap between web applications and desktop applications. They provide the benefits of a web applicationwhile still providing the snappy look and feel inherent to desktop applications.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.6
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• pp.36-46
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• 2002

This paper proposes an integrated scheduling mechanism for embedded system with real-time web server to meet the characteristics of real time task. The proposed scheduling mechanism may solve the so-called priority inversion problem in scheduling between urgent web requests and tasks with low priorities. The priority inversion problem happens because of operating two independent schedulers, web scheduler and operating system scheduler in a system without considering the requirements of each other. In the proposed mechanism, two schedulers are integrated in an operating system and the integrated scheduler schedules tasks for urgent web requests with real time characteristics and other application tasks together. Since all tasks are scheduled by one unified scheduler that knows the characteristics of tasks, the tasks are scheduled with their absolute priorities and thus the priority inversion problem can be eliminated. The performance is measured on a prototype embedded system with the proposed algorithm.

• Journal of the Korea Convergence Society
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• v.8 no.3
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• pp.115-121
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• 2017

Hospital medical services are making great efforts to provide prompt medical services to patients or improve the quality of medical services by convergence patient's healthcare information. However, recent research suggests problems about safety and efficiency when trying to transmit patient's healthcare information to hospital server via radio and wireless. In this paper, we propose a color model - based patient authentication key establishment protocol method to securely transmit patient healthcare information. The proposed method extracts randomly three color information used in the color model and vectorizes the extracted arbitrary information to obtain the key information required for user authentication as the sum of orthogonal vectors to improve the efficiency. In addition, the proposed method can securely generate key information used for user authentication without using an additional encryption algorithm. In performance evaluation result, proposed method shows that the server processing time of the sensed information is 8.1% higher than the existing method and 7.7% lower than the existing method.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.288-298
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• 1995

Load balancing attempts to improve the performance of a distributed computing system by transferring some of the workload of a congested site to others. A load balancing scheme that supports both the source-initiated and the server- initiated load balancing is proposed in this paper. It can model both the m/m/1 queue(no load balancing) and the m/m/n queue(perfect load balancing) as the extreme State variables are replicated into every site, and copy consistency constraints are relaxed more weakly. We propose weak copy consistency constraints which correlate the outdated state information to that of the current state. We also derive sufficient conditions under which each scheduler can guarantee the load balancing without communication Using this model, the problem of load balancing is converted to that of maintaining the consistency of states and communication overhead becomes less than that of the bidding algorithm. The scheme is simulated by event tracing, compared to the two extreme cases and the bidding algorithm. The results show that the mean response time and the number of messages are reduced by 0-35% and 40-100% respectively, compared with the bidding algorithm. Finally the effects of some system parameters are described.

• The KIPS Transactions:PartD
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• v.8D no.3
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• pp.221-232
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• 2001

Due to rapid advance of wireless communication technology, demand on data services in mobile environment is gradually increasing. Caching at a mobile client could reduce bandwidth consumption and query response time, and yet a mobile client must maintain cache consistency. It could be efficient for the server to broadcast a periodic cache invalidation report for cache consistency in a cell. In case that long period of disconnection prevents a mobile client from checking validity of its cache based solely on the invalidation report received, the mobile client could request the server to check cache validity. In doing so, some schemes may be more efficient than others depending on the number of available channels and the mobile clients involved. In this paper, we propose new cache consistency schemes, effects, efficient especially (1) when channel capacity is enough to deal with the mobile clients involved or (2) when that is not the case, and evaluate their performance.

• Journal of Digital Convergence
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• v.11 no.11
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• pp.415-420
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• 2013

U-WHS refers to a means of remote health monitoring service to combine fitness with wellbing. U-WHS is a system which can measure and manage biometric information of patients without any limitation on time and space. In this paper, we performed in order to look into the influence that the encryption module influences on the communication evaluation in the biometric information transmission gone to the smart mobile device and Hospital Information System.In the case of the U-WHS model, the client used the Objective-c programming language for software development of iOS Xcode environment and SEED and HIGHT encryption module was applied. In the case of HIS, the MySQL which is the Websocket API of the HTML5 and relational database management system for the client and inter-server communication was applied. Therefore, in WIFI communication environment, by using wireshark, data transfer rate of the biometric information, delay and loss rate was checked for the evaluation.

• Structural Engineering and Mechanics
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• v.40 no.1
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• pp.85-103
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• 2011

Integration of finite element analysis (FEA) software into various software platforms is commonly used in coupling systems such as systems involving structural control, fluid-structure, wind-structure, soil-structure interactions and substructure method in which FEA is used for simulating the structural responses. Integrating an FEA program into various other software platforms in an efficient and simple way is crucial for the development and performance of the entire coupling system. The lack of simplicity of the existing integration methods makes this integration difficult and therefore entails the motivation of this study. In this paper, a novel practical technique, namely CS technique, is presented for integrating a general FEA software framework OpenSees into other software platforms, e.g., Matlab-$Simulink^{(R)}$ and a soil-structure interaction (SSI) system. The advantage of this integration technique is that it is efficient and relatively easy to implement. Instead of OpenSees, a cheap client handling TCL is integrated into the other software. The integration is achieved by extending the concept of internet based client-server concept, taking advantage of the parameterization framework of OpenSees, and using a command-driven scripting language called tool command language (TCL) on which the OpenSees' interface is based. There is no need for any programming inside OpenSees. The presented CS technique proves as an excellent solution for the coupling problems mentioned above (for both linear and nonlinear problems). Application examples are provided to validate the integration method and illustrate the various uses of the method in the civil engineering.

• Journal of the Korean Geophysical Society
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• v.4 no.3
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• pp.145-162
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• 2001

With the rapid advance of internet service and the corresponding migration of service environment from the text-based one to WWW (World Wide Web) environment, the number of internet users is growing rapidly due to its easy usage. Accordingly, usage of internet as services for sending electronic mails to the other patry over the network is becoming increasingly prevalent. Web-based electronic mailing system is comprised of a server and a client The former provides the users with e-mail accounts and services, while the latter serves as a user interface. In other words, it enales those public users who dos not own e-mail accounts on the existing mail server to have an access to hte mailing service through the web. In this paper, we designed a effective web-based electronic mailing system which is based on the internet explorer and linux operating system, which overcomes limitations of the existing e-mail systes and this facilitates the development of a stable e-mail system by being able to avoiding the low system performance due to the bursty characteristics of e-mail messages and the increasing number of users.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.3B
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• pp.287-296
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• 2011

The white stick mainly used for visually impaired person has difficulty in providing location information and effective countermeasures for emergency situations encountered during walking as well as detecting floating obstacles on the ground. In this paper, we propose a machine-to-machine based intelligent walking assistance system for safe and convenient walking of the visually impaired. The proposed system consists of a walking assistance stick used by the visually impaired and a server supporting multiple stick users in remote places through mobile communication networks. The stick equipped with ultrasonic sensors, GPS(global positioning system) receiver and vibrator not only detects floating obstacles, but also offers stick users with present location identification utilizing a text-to-voice conversion technology. Besides providing geographic information, the server notifies the emergency locations of users to guardian and aid agency, and it provides log information during walking such as the place, time and the number of accidents. Test results with a developed prototype system have shown that the system properly performs the functions and satisfies overall system performance.