• The Transactions of the Korea Information Processing Society
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• v.5 no.3
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• pp.649-661
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• 1998

If there is redeveloping into the system applying the object-oriented paradigm, productivity Improvement of software through reuse would be accomplished and maintenance cost be reduced. When a procedure-oriented system is transformed to a type applying the object-oriented paradigm, various techniques are studied to extract objects from source code automatically or semi-automatically. However, it is not easy to extract conceptuat objects when those techniques are applied, This problem entails another problem which drops the conceptual integrity of the extracted objects. In this paper, we suggest an object extraction method and tool development to resolve the problem occurring at the time when thc pr"~r"m, dcveloped through procedure-oriented is transformed to an object-oriented system. The suggested method allow to extract the desired objects using object modeling for various application domains of the real world given source code and design recovery information. During the extraction process, functionality and global variables of the source code as well as its intcrface arc rigorously analyzed. This process can enhance the conceptual integrity of the objects and make easy to construct class hierarchies.

• The Transactions of the Korea Information Processing Society
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• v.4 no.7
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• pp.1733-1748
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• 1997

In this paper, we propose the classification scheme and retrieval mechanism which can apply to many application domains in order to construct the software reuse library. Classification scheme which is the core of the accessibility in the reusability, is defined by the hierarchical structure using the agglomerative clusters. Agglomerative cluster means the group of the reuse component by the functional relationships. Functional relationships are measured by the HACM which is the representation method about software components to calculate the similarities among the classes in the particular domain. And clustering informations are added to the library structure which determines the functionality and accuracy of the retrieval system. And the system stores the classification results such as the index information with the weights, the similarity matrix, the hierarchical structure. Therefore users can retrieve the software component using the query which is the natural language. The thesis is studied to focus on the findability of software components in the reuse library. As a result, the part of the construction process of the reuse library was automated, and we can construct the object-oriented reuse library with the extendibility and relationship about the reuse components. Also the our process is visualized through the browse hierarchy of the retrieval environment, and the retrieval system is integrated to the reuse system CARS 2.1.

• Journal of Broadcast Engineering
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• v.13 no.2
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• pp.261-273
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• 2008

Multimedia service whose use is rapidly increasing supports effective services to convert and transmit multimedia data based on network speed, noise circumstance, terminal computation, and type of contents for satisfying QoS. For supporting information protection of multimedia service, it offers middle level of singular security service or security mechanism which is based on policy of service provider, depending on present terminal computation and type of contents. It can support security mechanism for more effective multimedia service, if we study security of application layer and network layer for supporting multimedia service. In this paper, we propose Multimedia security framework reflected on quantitative analysis of the WLAN(Wireless Local Area Network) mesh network security using the utility function in the level of the sorority, violation and addictive compensation model.

• Journal of KIISE:Software and Applications
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• v.31 no.2
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• pp.203-212
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• 2004

The watermarking is a method to achieve the copyright protection of multimedia contents. Among several media, the left documents show very peculiar properties: block/line/word patterning, clear separation between foreground and background areas. So algorithms specific to the text documents are required that meet those properties. This paper proposes a novel watermarking algorithm for the grayscale text document images. The algorithm inserts the watermark signals through the edge direction histograms. A concept of sub-image consistency is developed that the sub-images have similar shapes in terms of edge direction histograms. Using Korean, Chinese, and English document images, the concept is evaluated and proven to be valid over a wide range of document images. To insert watermark signals, the edge direction histogram is modified slightly. The experiments were performed on various document images and the algorithm was evaluated in terms of imperceptibility and robustness.

• The Transactions of the Korea Information Processing Society
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• v.6 no.7
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• pp.1805-1816
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• 1999

This paper presents the Module Class Dependency Graph for expressing the dependency relations between classes effectively. The object-oriented language is developed independently at design time, and consists of relationship between classes. Therefore we need to consider these characteristics of independence, and to express effectively the relation of classes which is existed in class hierarchy. In the System Dependence Graph and Class Dependence Graph, the relationship of classes is not expressed. To express the class relationship, we propose the Module Class Dependence Graph, and we verify the effectiveness of this method applying to object constructor, inheritance relationship and dynamic binding. Also, we presents the expressing method of parameter to identify the member data of classes. Using this Module Class Dependency Graph, we can analyze the relationship of module class correctly at design time. This method can be applied to reverse engineering, testing, visualization and other various fields to analyze system.

• The Transactions of the Korea Information Processing Society
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• v.7 no.11S
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• pp.3723-3731
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• 2000

Recently, the growth of applications and services over high-speed Internet increase, ATM networks as wide area back-bone has been a major solution. The conventional TCP suite is still the standard protocol used to support upper application on current Internet and uses a window based protocol for flow control in the transport layer. When TCP data uses the UBR service in ATM layer, the control method is also buffer management. If a cell is discarded in ATM layer. one whole packet of TCP will be lost. Which is responsible for most TCP performance degradation and do not offer sufficiently QoS. To solve this problem, Several dropping strategies, such as Tail Drop, EPD, PPO, SPD, FBA, have been proposed to improve the TCP performance over ATM. In this paper, to improve the TCP fairness of end to end, we propose a packet dropping scheme algorithm using two fixed threshold. Under similar condition, we compared our proposed scheme with other dropping strategies. Although the number of VC is increased, simulation results showed that the proposed scheme can allocate more fairly each VC than other schemes.

• Journal of Korea Society of Industrial Information Systems
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• v.13 no.2
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• pp.8-17
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• 2008

Since different methods or protocols have been used to manage various mobile terminals, it has been difficult to manage mobile terminals efficiently. OMA(Open Mobile Alliance), therefore, proposed OMA DM(Device Management) as a standard for device management. In this paper, in an effort to apply the OMA DM concept ta real application area a home-delivery service management system using OMA DM agents is designed and implemented. The home-delivery service management system is developed using SyncML Tool Kit 4.3, SK WIPI SDK and Embedded Visual-C++ under the environment of SK-WIPI Clet. Since the home-delivery service management system is developed using OMA DD which is expected to be installed in most of the mobile terminals, separate lower level program modules for the management system would not be necessary. In order to justify this world some experiments are performed using SK WIPI emulator 1.1., which provides the same execution environments as a real mobile terminals does. Experiments show that the home-delivery service management system developed in this paper, works properly.

• Journal of KIISE:Software and Applications
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• v.33 no.3
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• pp.335-343
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• 2006

This paper proposes a novel technique of marker-based 2D-3D registration to combine 3D information obtained from preoperative CT images into 2D image obtained from intraoperative x-ray fluoroscopy image. Our method is divided into preoperative and intraoperative procedures. In preoperative procedure, we generate CT-derived DRRs using graphics hardware and detect markers automatically. In intraoperative procedure, we propose a hierarchical two- step registration to reduce a degree of freedom from 6-DOP to 2-DOF which is composed of in-plane registration using principal axis method and out-plane registration using minimal error searching method in spherical coordinate. For experimentation, we use cardiac phantom datasets with confirmation markers and evaluate our method in the aspects of visual inspection, accuracy and processing time. As experimental results, our method keeps accuracy and aligns very fast by reducing real-time computations.

• Journal of KIISE:Information Networking
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• v.33 no.1
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• pp.91-102
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• 2006

We analyze the performance of MAC-layer Reed-Solomon error recovery in the cdma2000 1xEV-DO Broadcast and Multicast Services (BCMCSs) environment, with respect to the size of the ECB (Error Control Block) and the air-channel condition, and establish the relationship between ECB size, error recovery capacity and service latency. From this we propose an adaptive error recovery scheme which adjusts the size of the ECB to reflect the environment of the mobile nodes so as to meet the required service quality (target bit error-rate), while reducing the latency of real-time applications. Extensive simulation results show the effectiveness of our approach compared to the current static scheme. Proposed adaptive schemes achieves near optimal solution with respect to service latency while satisfying the required service quality.

• Korean Journal of Remote Sensing
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• v.26 no.2
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• pp.99-108
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• 2010

According to the recent trend on advancement of web computing technologies and diversification of spatial data types to be processed, designing and implementing of web-based applications using open sources has been regarded as one of important users-needs. In this study, a kind of geo-browser model composed of client-middleware-DBMS stack is suggested, and the prototype implementation are performed. Especially, modularization of user interfaces is contributed to increase both applicability for a certain target system and accessibility for web users. In middleware, it has functions to decrease erroneous factors on spatial data registration processes, and provides spatial data the form of OGC WxS standards. It is thought that this system is helpful to utilize as basic architecture and the related implementation model for web-based geo-spatial services and their applications.