• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.440-448
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• 2011

The needs for the OpenGL-family of the rendering library standards are highly increasing, especially for the graphical human-machine Interface on the various systems including smart phones and personal information devices. Additionally, in the case of safety-critical market for avionics, military, medical and automotive applications, OpenGL SC, the safety critical profile of the OpenGL library plays the major role for the graphical interfaces. In this paper, we represent our OpenGL SC emulation library on the OpenGL 1.x rendering pipeline which is widely available on the existing embedded systems, to provide the features of OpenGL SC standard cost-effectively. Our method can provide the OpenGL SC features at the low development cost on the embedded systems, and its implementation is also one of the fundamental elements for the emulation of embedded systems in the PC environment. Our final result now works on both of Linux-based and VxWORKS systems, showing correct execution results at the reasonable speed.

• Spatial Information Research
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• v.21 no.3
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• pp.79-87
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• 2013

The purpose of this study focuses on the development of the lightweight BIM shape format(LBSF) structure to present the large volume BIM geometry object based on GIS as the viewpoint of the building facility management. Recently, the BIM-based facility management with GIS is researching with the purpose of the urban facility management etc. To implement these use-cases, the BIM geometry objects can be visualized based on urban level with GIS effectively. To do this, the lightweight BIM shape format is designed with the considerations and the prototype for the pilot test is implemented. In the pilot test phase, after developing the IFC file and LBSF file about the model data of the three areas, the performance with the data volume, the screen loading time etc was compared.

• Journal of IKEEE
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• v.17 no.3
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• pp.352-359
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• 2013

This paper proposes an entropy coding unit for H.264/AVC baseline profile. Entropy coding requires code tables for macroblock encoding. There are patterns in codewords of each code tables. In this paper, the patterns between codewords are analyzed to reduce the hardware cost. The entropy coding unit consists of Exp-Golomb unit and CAVLC unit. The Exp-Golomb unit can process five code types in a single unit. It can perform Exp-Golomb processing using only two adders. While typical CAVLC units use various code tables which require large amounts of resources, the sizes of the tables are reduced to about 40% or less of typical CAVLC units using relationships between table elements in the proposed CAVLC unit. After the Exp-Golomb unit and the CAVLC unit generate code values, the entropy unit uses a small size shifter for bit-stream generation while typical methods are barrel shifters.

• Journal of the Korean earth science society
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• v.30 no.3
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• pp.330-343
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• 2009

Pedagogical content knowledge (PCK) has been regarded as an indication of science teachers' professionalism. The purpose of this study was to analyze topic-specific PCK of pre-service and in-service science teachers, comparatively. For this purpose, we developed an analytic framework for explicitly documenting science teacher' PCK and applied the framework for analyzing the difference within the same topic and with two different topics. Findings are as follows: (1) With the same topic, there was considerable difference between pre-service and in-service teachers in the components of PCK, not to mention individual difference. (2) In case of two different topics, we did not recognize a tendency of change in PCK, but remarkable differences in PCK were identified between two different topics. This study affirmed the topic specificity of PCK, and discussed a possibility of employing PCK analytic framework and its profile as one of the tools that could be used to develop and assess teachers' professionalism.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.253-261
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• 2006

In spite of the popularity of P2P technology, a multimedia streaming using the P2P technology has been neglected. The reason for this is that the P2P multimedia streaming has suffered from several inherent problems especially poor bandwidth and unreliable connection among peers. We suggest a Multi-Peer Binding Protocol (MPBP) in this paper that provides a virtual single channel composed of multiple connections to several peers to ease these problems. The protocol enables applications to download data from multiple peers simultaneously, so they can achieve throughput improvement and reliable streaming. For this, the MPBP splits media files into small chunks and provides a mechanism for identifying and transmitting each chunk. Implemented MPBP engine focuses on handling an abrupt disconnection from data sending peers and the evaluation result shows the MPBP is able to handle it gracefully. The MPBP is also desisted to support various media types. To verify this, video and audio applications are implemented using the MPBP engine in this paper.

• The Journal of the Korea Contents Association
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• v.16 no.12
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• pp.181-191
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• 2016

We analyzed the search word of the media content in the IPTV service, and as a result we found that an important factor is general meta information as well as content(material, plot, etc.) and emotion information in the media content selection criteria of customers. Therefore, in this research, in order to efficiently provide various media contents of IPTV to users, we designed the emotion classification system for utilizing the emotion information of the media content. Next, we proposed 'personalized media contents curation system based on emotion information' for organizing the media contents, through the various processing steps. Finally, to demonstrate the effectiveness of this system, we conducted a user satisfaction survey(72.0 points). In addition, the results of comparing the results based on popularity and the results of the proposed system showed that the ratio leading to the actual users' viewing behavior was 10 times higher.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.6B
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• pp.697-709
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• 2011

For improvement of wireless Internet service quality at vehicle's moving speed, it is advised to reduce the service disruption time by reducing the handover frequency on vehicle's moving path. Particularly, it is advantageous to avoid the handover to cell whose dwell time is short or can be ignored in terms of service continuity and average throughput. This paper proposes the handover scheme that is suitable for vehicle in order to improve the wireless Internet service quality. In the proposed scheme, the handover process continues to be learned before being modeled to Discrete-Time Markov Chain (DTMC). This modeling reduces the handover frequency by preventing the handover to cell that could provide service sufficiently to passenger even when vehicle passed through the cell but there was no need to perform handover. In order to verify the proposed scheme, we observed the average number of handovers, the average RSSI and the average throughput on various moving paths that vehicle moved in the given urban environment. The experiment results confirmed that the proposed scheme was able to provide the improved wireless Internet service to vehicle that moved to some degree of consistency.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.293-301
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• 2011

This paper proposes a bridgeless half-bridge AC-DC converter with high-efficiency. The proposed converter integrates the bridgeless power factor correction (PFC) circuit with the asymmetrical pulse-width modulated (APWM) half-bridge DC-DC converter. It provides the isolated DC output voltage from the AC line voltage without using any full-bridge diode rectifier. Conduction losses are lowered with a simple circuit structure. Switching losses are also reduced by achieving zero-voltage switching (ZVS) of the power switches. By using series-connected two transformers, the proposed converter provides a low-profile and high power density for AC-DC converters. The performance of the proposed converter is verified from a 250 W (48 V / 5.2 A) experimental prototype circuit at $90 \;V_{rms}$ line voltage.

• The Transactions of the Korea Information Processing Society
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• v.4 no.8
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• pp.2017-2024
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• 1997

The main focus of this paper is the recognition of printed Hangul documents in terms of typeface, character size and character slope for IICS(Intelligent Image Communication System). The fixed-size blocks extracted from documents are analyzed in frequency domain for the typeface classification. The vertical pixel counts and projection profile of bounding box are used for the character size classification and the character slope classification, respectively. The MLP with variable hidden nodes and error back-propagation algorithm is used as typeface classifier, and Mahalanobis distance is used to classify the character size and slope. The experimental results demonstrated the usefulness of proposed system with the mean rate of 95.19% in typeface classification. 97.34% in character size classification, and 89.09% in character slope classification.

• The Journal of the Korea Contents Association
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• v.17 no.5
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• pp.317-325
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• 2017

There has been a growing interest in programming education recently. However, to use most programming languages the corresponding compiler and IDE have to be installed on computers. To tackle this issue, though there developed several web-based programming environment including Eclipse Che and JDOODLE, most of them does not support GUI nor Korean programming languages. This paper proposes a web-based programming environment called Bombart, which supports Saesark, a Korean programming language, with GUI output. It also supports a console-based input and output. To support both kinds of interfaces, two compiling subsystems are designed and implemented. To test the effectiveness of the GUI support of Bombart, all the Java tutorial codes on GUI are translated into Saesark and executed on top of Bombart. According to this test, 81.42% of codes can be successfully converted and executed.