• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.668-678
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• 2006

In designing a video-on-demand (VoD) system, one of the major challenges is how to reduce the viewer's waiting time maintaining a given bandwidth allocation and how to reduce the client's buffer requirements. To solve these problems, many VoD schemes were proposed. However, most VoD schemes require managing many segments of a video, frequency channel hopping, and using many channels at the same time. Therefore, to the complexity is a barrier to implementation. In this paper, we propose a fast staggered broadcasting scheme which has a simple structure and substantially improved VoD efficiency. The numerical results demonstrate that the viewer's waiting time of the fast staggered broadcasting scheme is close to the fast broadcasting scheme and the buffer requirements of this can be adapt for demanding rate by adjusting the short front part of a video sizes.

• Journal of Korea Multimedia Society
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• v.16 no.4
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• pp.493-501
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• 2013

A key challenge in massively multiplayer on-line game(MMOG) systems is providing real-time response latencies to the large number of concurrent game players. MMOG systems are a kind of soft real-time systems because requests from many players should be responded within specified time constraints. Client events have different timeliness and consistency requirements according to their nature in the game world. These requirements lead to tasks with different priorities on CPU processing. In order to meet their timing constraints, we propose priority scheduling methods that attempt to allocate preferentially more CPU bandwidth to serve an task with the higher priority level in the presence of transient overloading. The proposed scheduling methods are capable of enhancing real-time performance of MMOG system by maximizing the number of tasks with higher priority completed successfully within their deadlines while minimizing total average latency of tasks finished after given deadlines. The performance of these scheduling methods is evaluated through extensive simulation experiments.

• Korean Journal of Remote Sensing
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• v.13 no.1
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• pp.31-46
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• 1997

In recent years, as remotly-sensed image processing technologies have been improved and spread widely in the application areas, many new requirements for the image processing technologies have arisen. However, it is difficult and costly to access remotely-sensed image processing systems. Moreover, these systems have thier own processing facilities which are not easily accessible for general users. In this paper, those problems are challenged by adopting Internet as a universal information network for accessing remotly-sensed image DBMS and by allowing users to work remotely on the image processing. A remotly-sensed image processing system which can be accessed via Internet was designed and implemented. This system can be used to manipulate images over remote DBMS. The Illustra object-oriented relational DBMS with CGI(Common Gateway Interface) web interface was used in this project. The client consists of a WWW(World Wide Web) Netscap$e^{TM}$ browser, and the server consists of HTTPD(Web daemon), Illustra DBMS and Java modules in order to process the image being displayed. The developed system was tested on LAN environment and the service response time met the requirements.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.707-716
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• 2009

The role of cost modeller is to facilitate the design process by systematic application of cost factors so as to maintain a sensible and economic relationship between cost, quantity, utility and appearance which thus helps in achieving the client's requirements within an agreed budget. There are a number of research on cost estimates in the early design stage based on the improvement of accuracy or impact factors. It is common knowledge that cost estimates are undertaken progressively throughout the design stage and make use of the information that is available at each phase, through the related research up to now. In addition, Cost estimates in the early design stage shall analyze the information under the various kinds of precondition before reaching the more developed design because a design can be modified and changed in all process depending on clients' requirements. Parametric cost estimating models have been adopted to support decision making in a changeable environment, in the early design stage. These models are using a similar instance or a pattern of historical case to be constituted in project information, geographic design features, relevant data to quantity or cost, etc. OLAP technique analyzes a subject data by multi-dimensional points of view; it supports query, analysis, comparison of required information by diverse queries. OLAP's data structure matches well with multiview-analysis framework. Accordingly, this study implements multi-dimensional information system for case based quantity data related to design information that is utilizing OLAP's technology, and then analyzes impact factors of quantity by the design criteria or parameter of the same meaning. On the basis of given factors examined above, this study will generate the rules on quantity measure and produce resemblance class using clustering of data mining. These sorts of knowledge-base consist of a set of classified data as group patterns, of which will be appropriate stand on the parametric cost estimating method.

• Journal of KIBIM
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• v.13 no.4
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• pp.26-35
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• 2023

Recently, mandatory BIM design has been enforced in the civil engineering field, focusing on public projects, and inducement measures to actively participate in BIM by participating subjects are required. The BIM ordering documents must reflect the characteristics of the BIM project, current construction standards and laws, and environmental conditions of domestic participants. In this study, we analyze the ordering documents used in domestic and overseas civil engineering BIM projects to determine whether they meet the purpose of BIM. In the future, items that consider the existing heterogeneous data linkage and compatibility, the connectivity with the current construction guidelines and laws, the cost of the designer and the input personnel are prepared for the part that does not meet the BIM purpose. Furthermore, the written order documents are verified through interviews with experts who have experience in BIM projects. Through the results of this study, I would like to propose a consultation system strategy to prepare and present items according to the purpose and type of project by client.

• The KIPS Transactions:PartC
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• v.10C no.3
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• pp.273-280
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• 2003

When an existing user authorization systems in Grid access many user to local system and subject DN (Distinguished Name) in a user-proxy authenticate and ID in local system is one-to-one mapping, they have difficulties in ID management, memory resource management and resource management. At this, a variety of subject DN is shared of one local ID in an existing Grid. But this faces many difficulties in applying all requirements for many Grid users. Thus, we suppose user authorization system based on a certificate not them based on ID in this paper. That is, we add user's access level to extension field in a certificate, and make a supposed authorization system decide access limitation level on resources instead of an existing ID mapping methods.

• Journal of Korean Library and Information Science Society
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• v.40 no.3
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• pp.157-180
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• 2009

This study implements library toolbar in order to improve the accessibility of OPAC in the library. The toolbar elements are extracted on the basis of the importance of functionality for OPAC. After comparing the toolbar implementation approaches, this study develops the library toolbar with these elements as the client-based application that can fully realized the functionality of the toolbar. The librarians evaluate the usability of toolbar very affirmatively. This study also summarizes the further functionalities to upgrade toolbar proposed by the librarian. Through deploying the upgraded toolbar, the user requirements have to be analyzed and realized with the user survey.

• IE interfaces
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• v.14 no.3
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• pp.247-254
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• 2001

As current postal automation is limited to dispatch and arrival sorting, delivery sequence sorting is performed manually by each postman. It not only acts as a bottleneck process in the overall mailing process but is expensive operation. To cope with this problem effectively, delivery sequence sorting automation is required. The important components of delivery sequence sorting automation system are sequence sorter and Hangul OCR which function is to extract the address of delivery point. DSI database will be interfaced to both Hangul OCR and sequence sorter for finding the accurate delivery sequence number and stacker number. The objectives of this research are to develop DSI(Delivery Sequence Information) database prototype and client application for managing information effectively. For database requirements collection and analysis, we draw all possible sorting plans, and apply the AHP(Analytic Hierarchy Process) method to determine the optimal one. And then, we design DSI database schema based on the optimal one and implement it using Oracle RDBMS. In addition, as address information in DIS database consist of hierarchical structure which has its correspondence sequence number, so it is important to reorganize sequence information accurately when address information is inserted, deleted or updated. To increase delivery accuracy, we reflect this point in writing application.

• The KIPS Transactions:PartA
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• v.16A no.3
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• pp.181-188
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• 2009

Transcoding is one of core techniques that implement VoD services according to QoS. But it consumes a lot of CPU resource. A transcoding proxy transcodes multimedia objects to meet requirements of various mobile devices and caches them to reuse later. In this paper, we propose a service policy that reduces the load of transcoding multimedia objects by degrading QoS in a transcoding proxy. Due to the tradeoff between QoS and the load of a proxy system, a transcoding proxy provides lower QoS than a client's requirement so that it can accomodate more clients.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.6
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• pp.753-763
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• 1999

The existing SCADA(Supervisory Control and Data Acquisition) system software is usually developed to suitable for the specific hardware platforms. However, as per rapid improvement of computer performance and development of network technology, it is required to support scalability and inter-operability in existing different SCADA systems. In order to meet such requirements, in this paper, we propose a new type of SCADA testbed using Java for electric distribution applications. The system consists of three modules; development support tools, client and server modules. The basic architecture of the proposed SCADA system is similar to existing one, however, we improve the function of MTU and MMI interface to facilitate LAN and WAN environment. Also, the proposed system can deals with alarm and history data by using heterogeneous DBMS. Since the system is built in Java environment, the development cost is cheap and it can support sacalability and portability. Our experience can be utilized to develop next generation of small and medium size of SCADA system.