• Korean Journal of Remote Sensing
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• v.24 no.5
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• pp.389-396
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• 2008

In these days, various kinds of web applications based on web 2.0 paradigm have been developed. In web 2.0 paradigm pursuing participation, sharing, and openness on the web-as-platform, web mapping or web GIS application are regarded as top most applications, so that web applications, handling geo-spatial contents, with user-interaction interface and search engine of high performance have been provided for both public users and expert users in the special domains. Public and industrial needs for web mapping mashup application by open API, linked with the practical web computing technologies, are gradually increasing. In this study, a user interface in mashup for geo-spatial feature generation was implemented by using mainly Google maps API. Spatial database resources in this implementation are those of Google mapping server. As the results, public users on web client can create their own geo-spatial data sets in web vector formats, without the help of any GIS tools or access to proprietary databases. It is concluded that web-based mashup application in client-side using open API can be used as an alternative for geo-browsing system or portable feature generation system.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.1
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• pp.23-33
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• 2006

Key Agreement protocols are among the most basic and widely used cryptographic protocols. In this paper we present an efficient O-based authenticated key agreement (AKA) protocol by using bilinear maps, especially well suited to unbalanced computing environments : an ID-based AKA protocol for Server and Client. Particularly, considering low-power clients' devices, we remove expensive operations such as bilinear maps from a client side. Our protocol uses signcryption and provide security in random oracle model.

• Journal of Korea Multimedia Society
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• v.2 no.4
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• pp.459-467
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• 1999

With fully harnessing the functions provided by Windows NT, we suggest the generating method of RPL profile and the RPL protocol for remote booting on DL-NCS(Network Computing System for Diskless client PCs). This system can offer clients, without having hard disk, boot remotely Window 9x stored in server's hard disk and can share peripheral devices and application programs in the server side. For booting Window 9x from DL-NCS, twenty-five clients' PCs were set for simultaneous on and finally the PCs were booted in similar time interval compared to that from a desktop PC having local disk. This system was also experimented to the application programs. And this system can yield excellent networking environments. In sum, with using this DL-NCS, we can reduce the installing costs of peripheral device, recycle the lower grade PCs such as 486SX/DX, and save the budgets for software purchase.

• The Transactions of the Korea Information Processing Society
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• v.7 no.6
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• pp.1766-1777
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• 2000

In multimedia new service on the internet, there are problems such as server overload, network congestion and initial latency. To overcome these problems, we propose a proxy push-caching scheme that stores a portion of continuous media stream or entire stream, and a transmission scheme of NOD continuous media, RTP-RR and RTP-nR to exploit push-caching scheme. With the proposed push-caching scheme, NOD server pushes fixed portion of stream to a proxy when new data is generated, and the cached size of each stream changes dynamically according to the caching utility value of each stream. As a result, the initial latency of client side could be reduced and the amount of data transmitted fro ma proxy server to client could be increased. Moreover, we estimate a caching utility value of each stream using correlation between disk space occupied by the stream and the amount of data stream requested by client. And we applied the caching utility value ot replacement policies. The performance of the proxy push-caching and continuous media transmission schemes proposed were compared with other schemes using simulations. In the simulation, these schemes show better results than other schemes in terms of BHR (Byte Hit Rate), initial latency, the number of replacement and packet loss rate.

• Archives of design research
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• v.18 no.1 s.59
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• pp.185-194
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• 2005

The objectives of this research are to examine the relationships among designers' characteristics, mutual communication, conflicts between CI designer and client, to test the impacts of conflicts and four type of resolution strategies on the performance of CI development, and to recommend proper strategies for successful CI process and output management. The survey results show as follows. First, CI designers' confidentiality on clients' internal information and creative designing ability were found to affect mutual communication between them. Second, proper communication was found to lessen the conflict level which in turn yielded the positive performance of CI development, especially for the clients' side. Third, it is suggested that the conflict level be first reduced and conflict resolution strategies be applied depending upon the conflict level and related party of designer or client position, respectively.

• Convergence Security Journal
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• v.12 no.4
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• pp.9-15
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• 2012

In recently years, repackaged malwares are becoming increased rapidly in Android smartphones. The repackaging is a technique to disassemble an app in a market, modify its source code, and then re-assemble the code, so that it is commonly used to make malwares by inserting malicious code in an app. However, it is impossible to collect all the apps in many android markets including too many apps. To solve the problem, we propose RePAD (RePackaged App Detector) scheme that is composed of a client and a remote server. In the smartphone-side, the client extracts the information of an app with low CPU overhead when a user installs the app. The remote server analyzes the information to decide whether the app is repackaged or not. Thus, the scheme reduces the time and cost to decide whether apps are repackaged. For the experiments, the client and server are implemented as an app on Galaxy TAB and PC respectively. We indicated that seven pairs of apps among ones collected in official and unofficial market are repackaged. Furthermore, RePAD only increases the average of CPU overhead of 1.9% and the maximum memory usage of 3.5 MB in Galaxy TAB.

• Journal of Internet Computing and Services
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• v.12 no.6
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• pp.53-62
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• 2011

In this paper, we introduce a method of graphic offloading computing using a GPU virtualization technology in order to provide high demanding software like 3D software as an on-line software service. When the offloading software is executed on server's software virtualization environment, its graphic works are processed on a client's GPU using GPU virtualization, while on the other its data works are processed on server's CPU. To do that, we propose a method of rendering graphics information on client side GPU using API Remoting method. Also, we show the better performance than server based rendering method when we serve offloading software which include dynamical 3D graphics that display images are frequently changed through on-line. Moreover, we describe a method to virtualize offloading software by a process level and manage client's configuration information in order to decrease server's load when we provide software service to multiple clients.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.4
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• pp.123-130
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• 2018

Many massively multiplayer online games(MMOG) use client-server architectures that have enormous server-side bandwidth requirements. In this paper, we propose a region-based hybrid game architecture that combines the advantages of client-server and peer-to-peer architectures, so that only critical events changing game state are processed by the server. In this hybrid architecture, the central server divides the game into regions and assigns a player as a regional server to distribute important updates for that region. Thus, the central server sends state updates to the players through the regional servers. All players in the same region directly exchange updates without affecting game state. This division of labor greatly reduces server bandwidth significantly and enables it to serve larger number of concurrent players. Our experiments show that the region-based hybrid architecture with three-level hierarchy scales better than the client-server architecture, saving considerable bandwidth at the central server while requiring enough bandwidth of players acting as regional servers.

• The KIPS Transactions:PartD
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• v.18D no.3
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• pp.205-214
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• 2011

Client based web mashups have become one of the most important architecture in web application development. Although there are well known methods to generate presentation view codes for web services, navigations between views and service requests are still developed manually in most web mashups. In this paper, we propose the concept of deterministic data binding from output data to input parameters of another method. Using binding relations, we can model navigation menus for service method requests. For a given set of data mappings between services, we investigate context dependent binding conditions and discuss the generation of views and navigation menus. The proposed approach provides UI for users to navigate services of client mashup page using simple and convenient interface even when the number of services and the size of the mashup page grows. In order to show the usability of the proposed approach, we present a historic tourism service.

• Journal of KIISE:Computing Practices and Letters
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• v.10 no.6
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• pp.435-447
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• 2004

For VOD systems, it is important to provide QoS to more users under the limited resources. To analyze QoS issues in real environment, we implement clustered VOD server and embedded client system based on the Linux open source platform. The parallel processing of MPEG data, load balancing for nodes and VCR like functions are implemented in the server side. To provide more user friendly interface, the general TV is used for a VOD client's terminal and the embedded board is used supporting for VCR functions. In this paper, we measure the performance of the implemented VOD system under the various user requirement features and evaluate the sources of performance limitations. From these analyses, we propose the dynamic admission control method based on the availability memory and network bandwidth. The proposed method enhances the utilization of the system resource for the more QoS media streams.