• The Journal of Korean Association of Computer Education
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• v.4 no.1
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• pp.175-181
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• 2001

WBI provides new opportunities to realize the flexible learning environment based on hypermedia and to support distance learning with a diverse interaction. The instructors or learners in WBI claim to be able to resolve reluctant fluctuations such as disorientation and cognitive overload. To overcome these phenomena, a supplementary tool able to manage a learning space organized by the instructor's or learner's own way and offer effective navigation techniques is presented in this paper. A learning space management and navigation tool called HyperMap dynamically represents the learning space in the form of a two-dimensional labeled graph. This HyperMap also can be used for an instruction design tool, learners portfolio for the exchange of learning experiences, and the assessment of WBI.

• Journal of KIISE
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• v.43 no.9
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• pp.1026-1033
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• 2016

Path-finding on a grid map is a problem generally addressed in the fields of robotics, intelligent agents, and computer games. As technology advances, virtual game worlds tend to be represented more accurately and more realistically, resulting in an excessive increase in the number of grid tiles and in path-search time. In this study, we propose a path-finding algorithm that allows a prompt response to real-time queries by constructing a reduced state space and by precomputing all possible paths in an offline preprocessing stage. In the preprocessing stage, we vertically decompose free space on the grid map, construct a connectivity graph where nodes are the decomposed regions, and store paths between all pairs of nodes in matrix form. In the real-time query stage, we first find the nodes containing the query points and then retrieve the corresponding stored path. The proposed method is simulated for a set of maps that has been used as a benchmark for grid-based path finding. The simulation results show that the state space and the search time decrease significantly.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.6
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• pp.85-94
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• 2015

In this paper, an enhanced QoS multicast routing scheduling scheme is proposed to adapt to a dynamic mobile traffic condition for wireless mesh networks (WMNs). It handles the network QoS by controlling the delay constraints for multimedia applications. The group size will be controlled according to both the current network state and QoS requirements. The dynamic reconstruction of QoS multicast tree can be obtained from preprocessing with both the partial multicast routing scheme and the traffic estimation. Performance evaluation of the proposed scheme is carried out on randomly generated graph derived from the wireless mesh network, by choosing the optimal value related to the appropriate delay bounds. Simulation results show that the proposed scheme can improve the performance of QoS multicast routing for WMNs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.2
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• pp.1426-1433
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• 2015

CCTV-applied monitoring is an effective measure to suppress potential crimes and record objective relationship; however, there is no methodology that can quantitatively compare and assess the afore-mentioned effects. Thus, this study intended to construct the methodology and analysis application that can measure the changes in the space-corresponding performance of CCTVs depending on installation measures by using 3-dimenstional virtual simulation technology. For analysis, the raster-based Isovist theory was 3-dimensionally expanded and the amount of incident sight line to each point was accumulated. At the same time, the amount of overlapped monitoring in the CCTV cameras that were connected to each measurement node was accumulated for cross-analysis. By applying the examples and analyzing the results, it was possible to construct an analysis application in use of collision detection model and quantify the changes of monitoring performance depending on positioning alternative of the cameras. Moreover, it enabled intuitive review and supplementation by reproducing visible shadow areas in a graph.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.431-439
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• 1997

This paper describes the development of a decision support system (DSS) for the real time reservoir operation that aims to maximize the flood control effect. In the decision support system, model base and real time data processing subsystem are included along with the graphical user interface(GUI) that is able to visualize the forecasted runoff hydrographs at the flood control points and reservoir water levels resulting from the model run as well as the current hydrologic status. The system was verified through the pseudo real time applications to the Taechong reservoir operation with the historical flood events of the Kum river basin occurred in July, 1987 and August, 1995, Decision making processes were performed using the developed system and the results were compared with the real operations at that time. The reservoir operation using the pseudo real time application of DSS were simulated by the flood runoff simulation model, that shows the reservoir operation by DSS were successful in flood control for the lower Kum River.

• KIPS Transactions on Software and Data Engineering
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• v.11 no.1
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• pp.59-66
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• 2022

In this paper, by applying IoT technology to the Ultimate game, which is one of the games using Flyingdisc, the process of the game is traced based on the players and the flyingdisc, and a comprehensive relationship analysis between players is performed on the results of the game. A WiFi module with built-in GPS is attached in the players and flyingdisc. The player's ID, latitude/longitude values received from GPS and time are stored in the database in realtime during the game. Process informations of the game is also stored in the database at the same time using mobile Ultimate game App. Based on this informations after the game is over, we developed a system that can perform comprehensive analysis of the game contents. By using the informations stored in the database, the player-based game process and the flyingdisc-based scoring process are visualized in the virtual playground. Various game result informations for players are graphically analyzed using Python.

• Journal of the Korean School Mathematics Society
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• v.25 no.4
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• pp.333-352
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• 2022

This study is aimed at developing the STEAM instruction materials for mathematics subject-based advanced technology and ICT teaching tools. In order to develop the STEAM materials, a PDI model in which the implementation and evaluation steps were simplified to Improvement was used. The developed STEAM materials were revised and supplemented by a group of experts. The subject of the STEAM class material developed in this study is 『Graph! The bridge that connects the past, present and future』 , 『You are the same but different!』 , 『Creating a virtual reality three-dimensional space together』 , 『And making interesting figures』 and 『Cover the roof of the turtle ship!』 . As a suggestion based on the results of this development study, various STEAM education materials should be developed and shared so that STEAM education can be performed in the elementary education field. And for the spread and settlement of STEAM education, the cultivation and expansion of STEAM education capabilities of on-site elementary school teachers or pre-service teachers will be an absolute prerequisite. And this suggests the need for a continuous and long-term approach to follow-up research on STEAM education.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.296-299
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• 2008

최근 데이터 스트림을 관리하기 위해 DSMS(Data Stream Management System)가 계속적으로 연구 되고 있다. 하지만 데이터 스트림은 방대한 양의 데이터를 처리하기 위하여 실시간성을 갖는 빠른 데이터 처리가 요구되며, 이러한 특성 때문에 데이터 처리의 효율성 증대를 위하여 메모리 관리가 중요하다. 기존 메모리 관리에 대한 연구는 쓰레드 스케줄링을 통한 관리 기법이 연구되었다. 하지만 기존의 연산자 쓰레드 스케줄링과 그래프 쓰레드 스케줄링은 쓰레드 관리의 유연성이 떨어지기 때문에 불규칙적인 데이터 스트림 환경에서는 부적합하다. 또한 하이브리드 멀티 쓰레드 스케줄링 기법은 두 가지 기법의 장점을 결합하였으나 가상 연산자의 일회성 사용으로 쓰레드 관리의 어려움 이 있다. 따라서 본 논문은 공유와 재사용이 가능한 링 연산자를 이용한 링 연산자 쓰레드 스케줄 링 기법을 제안한다. 본 기법은 링 연산자를 통해 새로 입력된 질의의 동일한 연산자 구성은 생성 되어 있는 링 연산자를 공유하거나 재사용하여 불필요한 자원 소모와 자원 할당의 과부하를 줄임으로써 기존 기법에 비해 쓰레드 할당의 수를 감소 시켜 대량의 질의 처리 시 속도를 증가 시켰다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.181-187
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• 2020

In this paper, we proposed a register allocation algorithm and resource allocation algorithm in the high level synthesis process for the SoC design synthesis system of high performance vehicles We have analyzed to the operator characteristics and structure of datapath in the most important high-level synthesis. We also introduced the concept of virtual operator for the scheduling of multi-cycle operations. Thus, we demonstrated the complexity to implement a multi-cycle operation of the operator, regardless of the type of operation that can be applied for commonly use in the resources allocation algorithm. The algorithm assigns the functional operators so that the number of connecting signal lines which are repeatedly used between the operators would be minimum. This algorithm provides regional graphs with priority depending on connected structure when the registers are allocated. The registers with connecting structure are allocated to the maximum cluster which is generated by the minimum cluster partition algorithm. Also, it minimize the connecting structure by removing the duplicate inputs for the multiplexor in connecting structure and arranging the inputs for the multiplexor which is connected to the operators. In order to evaluate the scheduling performance of the described algorithm, we demonstrate the utility of the proposed algorithm by executing scheduling on the fifth digital wave filter, a standard bench mark model.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.3
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• pp.26-31
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• 2009

A new LFSR based test compression scheme is proposed by reducing the maximum number of specified bits in the test cube set, smax, virtually. The performance of a conventional LFSR reseeding scheme highly depends on smax. In this paper, by using different clock frequencies between an LFSR and scan chains, and grouping the scan cells, we could reduce smax virtually. H the clock frequency which is slower than the clock frequency for the scan chain by n times is used for LFSR, successive n scan cells are filled with the same data; such that the number of specified bits can be reduced with an efficient grouping of scan cells. Since the efficiency of the proposed scheme depends on the grouping mechanism, a new graph-based scan cell grouping heuristic has been proposed. The simulation results on the largest ISCAS 89 benchmark circuit show that the proposed scheme requires less memory storage with significantly smaller area overhead compared to the previous test compression schemes.