• Journal of Korea Technology Innovation Society
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• v.8 no.1
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• pp.135-153
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• 2005

With an explosive growth of internet and a change of consumer's demand, Post PC is emerging as a substitute for the existing desktop computer and laptop computer. Post PC is a new computer which is portable with wireless networking, cheaper than the existing PCs and specialized in the specific function that consumers want. Furthermore, the shape and the ability of Post PC are dependent on its specific function. The rudimentary Post PCs such as PDA, web-pad and smart-phone are already usable. And in the future, owing to the progress of technologies, the heterogeneity of relate companies and the low entry barrier, various Post PCs will be developed. In this paper, we analyze consumers' willingness-to-pay for Post PC with the attributes such as the portability, the speed of CPU, the data input method (using key board, or notepad etc), the size of monitor and price. To estimating consumers' willingness-to-pay for the attributes of Post PC, we apply a contingent ranking method, which makes the respondents rank hypothetical Post the portability, the speed of CPU, the data input method (using key board, or notepad etc),the size of monitor and price. To estimating consumers' willingness-to-pay for the attributes of Post PC, we apply a contingent ranking method, which makes the respondents rank hypothetical Post PC alternatives featuring various combinations of attributes, to a survey data collected in Korea. Using the estimated willingness-to-pay, we predict the shape and the ability of future's Post PC and draw policy implications for the national and company level R&D strategies.

• Journal of Biosystems Engineering
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• v.27 no.3
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• pp.185-194
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• 2002

The objective of this study was to analyze a stability of sideways overturning of a forwarder developed by the Forestry Research Institute. The stability analysis was conducted using a multibody dynamic analysis program. VisualNastran Desktop. A solid model of the forwarder was constructed and its physical properties such as mass, mass center and mass moment of inertia were determined on 3D CAD modeler of the Solid Edge 8.0. 3D simulations of sideways overturning of the forwarder were also performed on the Visual Nastran using the solid model when it traveled across the slope and traversed over an up-hill side obstacle. Stability comparison between a bogie-wheeled and a 6-wheeled forwarders was also made and found that the bogie-wheeled forwarder was more stable than the 6-wheeled one on slopes. The safety speeds of the forwarder predicted by the simulation under various conditions can be used as a guideline for safe operations of forwarders in mountainous area. The technique of using a solid model for the sability analysis can also be applied successfully to other vehicles like agricultural tractors, loaders and construction equipments.

• Journal of the Korea Computer Industry Society
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• v.3 no.12
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• pp.1759-1764
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• 2002

Linux was developed by Linus Torvalds at University of Helsinkyi, Finland. Today Linux becomes to compete with windows operation of Microsoft. and is adopted worldwide on IBM products. The British government is viewing Linux as a desktop operating system. In Tunisia, Linux is under consideration as the governmental operating system. Even Sun Microsystems, the powerful supplier in workstation and sewer market, is working on developing ways in using Linux. is now getting further attentions on governmental level in several countries. The growing interests in adopting Linux in computer operating systems are not on a personal preference level any more. A number of companies and organizations, even some governmental administrations start to see its potential capabilities and are looking for ways for its applications. The necessity of teaching Linux in university is, therefore, imminent and should be discussed in course development without delay. The purpose of this paper is showing the things to be considered, problem analysis and some solution as grafting Linux in university education.

• Journal of Korea Multimedia Society
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• v.8 no.1
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• pp.71-78
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• 2005

When a PDA is used as a mobile terminal in an infrastructure network based on 802.11b standard wireless LAN, we measured and evaluated the performance of multimedia data transmission. In general, PDAs are mainly used tot receiving bulk data like multimedia data. However, while a PDA as a mobile host transfers multimedia data to a desktop PC as a fixed host in such a network, the time taken to receive data from the PC to the PDA is always longer than the time taken to send data from the PDA to the PC by at least 53%. Thus, we consider some critical factors that affect the time taken to receive Our experimental results show that with the PDA the time taken to access a file for writing is longer than the time taken to access a file for reading of to 4.11 times. In addition, a dramatic change of the site of the receiver window, from 686 bytes to 32,383 bytes, prolongs the time taken to receive. To transfer data without any inter-packet interval for the PDA and to increase the size of the TCP receive buffer will be effective in improving the delay to receive data.

• KIISE Transactions on Computing Practices
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• v.21 no.12
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• pp.786-791
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• 2015

The environment of Internet of Things (IoT) wherein various devices are connected through the Internet with value-added network functions, is currently a subject of active study. Accordingly, the existing computing environment based on desktop or mobile systems is being expanded into a computing environment of more diverse devices. Because the response of program launching is important in terms of User Experience (UX) in IoT environments, the technology for guaranteeing rapid response of program launching in IoT devices is getting the focus of much current research. In this paper we analyze the Zygote technique, which is being used for faster program execution in Android systems, and, based on our results, we propose an address space maintaining scheme for the rapid launching of programs for use in Linux-based systems. Our scheme utilizes the Copy on Write (CoW) technique in Linux systems as well as the Zygote technique of Android systems. In order to evaluate the proposed scheme, we implemented our scheme on Linux systems and performed several experiments. The experimental results show that the proposed scheme shortens the launching time up to 99%, compared to the existing technique.

• Journal of KIISE:Computing Practices and Letters
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• v.13 no.5
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• pp.260-270
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• 2007

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. However, since mobile clients use wireless network and the wireless network have less stable bandwidth according to distance from AP and environments, it is hard to support stable QoS to mobile clients. In this paper, we propose a dynamic bit rate control method for transcoding in order to supprot stable QoS of streaming media service to mobile clients via wireless network. The proposed method is shown to serve seamless streaming media service with adaptive bit rate control according to state of wireless network in real time and to reduce transmission failure from experiment.

• The Journal of the Korea Contents Association
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• v.10 no.10
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• pp.120-127
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• 2010

Today we always can take a picture and enjoy it anywhere and anytime with a propagation of digital camera and camera phone. Even though the amount of digital picture content produced in every day life has been increasing, the way of enjoying it was just with phones or PC monitors. A small size screen of a cell phone and a desktop monitor are not suitable environment for enjoying digital picture, so the new market for digital photo frame has been opened. Until now, various kind of digital photo frames of many manufactures have been released for several years, but they have similar interaction way each other due to the limitation of their hardware specification so don't fill the intuitive mental model that users have about the product called a photo frame. Thus, this research aims to suggest an interaction way of digital photo frame providing with better usability and emotional satisfaction according to the spatial environment that it's located and users' behaviors.

• Journal of KIISE:Computer Systems and Theory
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• v.35 no.9_10
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• pp.466-475
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• 2008

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. Transcoding servers transcode the source media to the target media within corresponding grades and provide QoS in real-time. In particular, an effective load balancing policy for transcoding servers is inevitable to support QoS for large scale mobile users. In this paper, the transcoding load estimation algorithm is proposed for load balance on the distributed transcoding environments. The proposed algorithm estimates transcoding time from transcoding server information, movie information and target transcoding bit-rate. The estimated transcoding time is proved based on experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.6
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• pp.2707-2712
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• 2012

Desktop-based computing environment is changed into mobile computing using smart phone and cloud computing providing common behavior and big data by network. Because of this transformation software development and operating environment is changed into heterogeneous distributed environment. As a result, dynamic service composition or changement is required. However, there is few research of techniques supporting service composition or changement dynamically in this situation. This paper suggests a technique for customizing services dynamically of mobile applications based on android platform. Especially we propose a customization technique of service by applying ontology technique to improve sharing and reuse of service. We applied proposed technique into meeting notification system, and obtain that it can be customized into various services such as email, sms, twitter service, and so on.

• Journal of Korea Multimedia Society
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• v.14 no.10
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• pp.1335-1347
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• 2011

The dissemination and use of mobile applications have been rapidly expanding these days. And in such a situation, the security of mobile applications has emerged as a new issue. Although the safety of general software such as desktop and enterprise software is systematically achieved from the development phase to the verification phase through secure coding, there have been not sufficient studies on the safety of mobile applications yet. This paper deals with deriving weakness enumeration specialized in mobile applications and implementing a tool that can automatically analyze the derived weakness. Deriving the weakness enumeration can be achieved based on CWE(Common Weakness Enumeration) and CERT(Computer Emergency Response Team) relating to the event-driven method that is generally used in developing mobile applications. The analysis tool uses the dynamic tests to check whether there are specified vulnerabilities in the source code of mobile applications. Moreover, the derived vulnerability could be used as a guidebook for programmers to develop mobile applications.