• Journal of KIISE:Databases
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• v.32 no.6
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• pp.616-627
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• 2005

In the shared storage file system, systems can directly access the shared storage device through specialized data-only subnetwork unlike in the network attached file server system. In this shared-storage architecture, data consistency is maintained by some designated set of lock servers which use control network to send and receive the lock information. Furthermore, lease mechanism is introduced to cope with the control network failure. But when the control network is partitioned, participating systems can no longer make progress after the lease term expires until the network recovers. This paper addresses this limitation and proposes a method that allows partitioned systems to make progress under the partition of control network. The proposed method works in a manner that each participating system is rotationally given a predefined lease term periodically. It is also shown that the proposed mechanism always preserves data consistency.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1327-1334
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• 2004

The purpose of this paper is to implement Web 3D environment that is not provider - oriented but client-oriented in order to provide dynamic information and to analyze knowledges by executing programs on Web pages. For these, The 3D Viewer program that parses and renders ASE files - the most general 3D Model Data file and exported text file of 3D Max Studio - is made and then converted into ActiveX 3D Viewer Component that can be used on the Web. With the purpose of managing ASE and texture file efficiently and interacting between clients and server, ActiveX Component link ASP and Database with Web Service. The 3D View Web Service can make dynamic information and cooperative works easier in Networked Virtual Reality.

• Journal of KIISE:Computer Systems and Theory
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• v.36 no.4
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• pp.247-258
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• 2009

Distributed file systems running on a cluster of inexpensive commodity hardware are being recognized as an effective solution to support the explosive growth of storage demand in large-scale Internet service companies. This paper presents the design and implementation of BeanFS, a distributed file system for large-scale e-mail services. BeanFS is adapted to e-mail services as follows. First, the volume-based replication scheme alleviates the metadata management overhead of the central metadata server in dealing with a very large number of small files. Second, BeanFS employs a light-weighted consistency maintenance protocol tailored to simple access patterns of e-mail message. Third, transient and permanent failures are treated separately and recovering from transient failures is done quickly and has less overhead.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.849-856
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• 2008

As the XML is used as the standard format for information delivery and exchange in various fields, the SVG is frequently used as a user interface or expression tool for the embedded system like an internet based mobile phone. The SVG file must contain additional information specifying the structure of the document and it consumes more transmission time than the actual data sent. The SMETA(Svg transmission MEthod using Semantic meTAdata) system[9] is a study to reduce the size of the SVG file by partitioning the SVG file to a minimal size and assigning meaningful meta data to each portion of the data. In this paper, instead of the meta data exchange method for reducing the size of the file exchanged in the existing SMETA system, we studied an improved version of SMETA system that analyzes the data for each user in the server system and only transmits the data that a user needs. In addition, through our simulation, we verified that it provides better performance than the existing system even if encryption is used.

• Journal of Software Assessment and Valuation
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• v.10 no.1
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• pp.19-26
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• 2014

In this paper, we propose a method for protecting Android applications against reverse engineering attacks. In this method, the server encrypts the original executable code (DEX) included in an APK file, inserts into the APK file a stub code that decrypts the encrypted DEX later at run-time, and distributes the modified APK file. The stub code includes an integrity validation code to detect attacks on itself. When a user installs and executes the APK file, the stub code verifies the integrity of itself, decrypts the encrypted DEX, and loads it dynamically to execute. Since the original DEX is distributed as an encrypted one, we can effectively protect the intellectual property. Further, by verifying the integrity of the stub code, we can prevent malicious users from bypassing our method. We applied the method to 15 Android apps, and evaluated its effectiveness. We confirmed that 13 out of them operates normally.

• KIISE Transactions on Computing Practices
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• v.21 no.10
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• pp.658-669
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• 2015

The paradigm of game development changes with technological trends. If the system can analyze and determine undefined inputs, users' input choices are not restricted. Therefore, game scenarios can have multifarious flows depending upon the user's input data. In this paper, we propose a method of including an output plan in the game system that is based on the user's input but is not restricted to predefined choices. We have implemented an experimental game on the Android platform by combining network communication and APIs. The game interface works as follows: first, the user's input data is transmitted to the server using HTTP protocol; then, the server carries out an analysis on the input data; and finally, the server returns the decision result to the game device. The game can provide users a scenario that corresponds to the decision results. In this paper, we used an image file for the user's input data format. The server calculates similarities between the user's image file and reference images obtained from the Naver Image Search API and then returns determination results. We have confirmed the value of integrating the game development framework with other computing technologies demonstrating the potential of the proposed methods for application to various future game interfaces.

• Journal of Broadcast Engineering
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• v.7 no.2
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• pp.114-125
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• 2002

Although there have been a lot of researches on a video abstraction algorithm, the video abstraction tool is necessary to correctly pick up some important shots in a video because the important shots might vary on the person's subjectivity. This paper proposes a video abstraction and search system for making a video abstraction automatically or manually. Proposed system has two main components, server and client. The server generates the Metadata and makes a video abstraction file. The description for video abstraction file is based on MPEG-7. Since proposed system has a function to manually correct the results of each step, the author could produce a good video abstraction easily and efficiently. The proposed system could be used to build a digital video library.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1095-1104
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• 2000

In recent years, medical procedures have become more complex, while financial pressures for shortened hospital stays and increased efficiency in patient care have increased. As a result, several shortcomings of present film-based systems for managing medical images have become apparent. Maintaining film space is labor intensive and consumes valuable space. Because only single copies of radiological examinations exist, they are prone to being lost or misplaced, thereby consuming additional valuable time and expense. In this paper, mini-PACS for image archiving, transmission, and viewing offers a solution to these problems. Proposed mini-PACS consists of mainly four parts such as web module, client-server module, internal module, acquisition module. In addition, mini-PACS system includes DICOM converter that non-DICOM file format converts standard file format. In client-server module case, proposed system is combined both SCU (service class user: client) part and SCP(service class provider: sewer)part therefore this system provides the high resolution image processing techniques based on windows platform. Because general PACS system is too expensive for medium and small hospitals to install and operate the full-PACS. Also, we constructed web module for database connection through the WWW.

• Journal of Korea Multimedia Society
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• v.4 no.5
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• pp.446-454
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• 2001

A long-distance education method using the computational environment has been developed and implemented for quite some time. However, there has been some difficulty in the simulation of face-to-face instruction due to limitations in performance of the computers and the networks. Continued development of multimedia technologies has now made it possible to simulate face-to-face instruction, recording the teachers' instructions in the form of a screen dump. In this paper, we propose a system that allows the teacher to make loaming materials available on the Web using Window Media Technology(WMT). This technology also allows remote site users to view the contents at their convenience. A media encoder acquires the lessons and stores them as moving pictures. The lessons are displayed on the screen as the teacher explains them. The learning materials are stored in a Windows media file format, the file is stored on a lecture server and provided to the user using a streaming method in real time. The users can view the contents on the Web without requiring a special player. The proposed system consists of a lecture writer module, a lecture server module and a lecture client module.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1405-1408
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• 2005

An embedded system has been applied to many fields including households and industrial sites. In the past, user interface products with simple functions were commercialized .but now user demands are increasing and the system has more various applicable fields due to a high penetration rate of the Internet. Therefore, the demand for embedded system is tend to rise In this paper, we Implementation of an embedded system for image tracking. This system is used a fixed IP for the reliable server operation on TCP/IP networks. A real time broadcasting of video image on the internet was developed by using an USB camera on the embedded Linux system. The digital camera is connected at the USB host port of the embedded board. all input images from the video camera is continuously stored as a compressed JPEG file in a directory at the Linux web-server. And each frame image data from web camera is compared for measurement of displacement Vector. That used Block matching algorithm and edge detection algorithm for past speed. And the displacement vector is used at pan/tilt motor control through RS232 serial cable. The embedded board utilized the S3C2410 MPU Which used the ARM 920T core form Samsung. The operating system was ported to embedded Linux kernel and mounted of root file system. And the stored images are sent to the client PC through the web browser. It used the network function of Linux and it developed a program with protocol of the TCP/IP.