• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.561-564
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• 2010

의학과 기술 발달로 인해 질병과 사고에 의한 사망률은 줄어들었으나, 심장 관련 질환에 의한 사망률은 증가하였다. 심장 질환을 예방하는 데는 정기적인 검진을 통해 심장기능을 분석하고 관찰하는 것이 중요하다. 심장 기능의 분석은 이완기와 수축기 사이의 혈류량 및 심박구출률 계산을 통한 심장 운동능력 평가에 의해 이루어진다. 본 연구에서는 심장 단축 자기공명영상에서 좌심실 영역을 자동 분할하여 혈류량 및 심박 구출률을 계산하는 알고리즘을 제안한다. K평균 군집화 기법을 적용하여 좌심실을 분할하고, 그래프 탐색 기법에 기반하여 분할 오류를 수정하였다. 15명의 지원자에 대해 제안하는 알고리즘을 사용하여 혈류량과 심박구출률을 계산하였고, 수동윤곽검출 및 General Electronics 사의 MASS 소프트웨어와 비교하였다. 제안한 알고리즘의 수동윤곽검출과 차이는 혈류량의 경우 평균적으로 이완기에 $4.6mL{\pm}3.9$, 수축기에 $2.1mL{\pm}2.4$로 나타났고, 심박구출률은 $1.8%{\pm}1.7$이었다. 전반적으로 MASS소프트웨어에 비해 좋은 성능을 나타내었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.4
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• pp.539-549
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• 1999

In this paper, the bit error rare (BER) performance of DS/CDMA DQPSK communication system in the presence of multi access interference, impulsive noise and Nakagami fading is investigated. The DS/CDMA DQPSK communication system adopts Maximum Ratio Combining (MRC) diversity reception and error correcting BCH code technique to enhance system performance. Using the derived error probability equation, the error rate performance of DS/CDMA DQPSK communication system has been evaluated and shown in figures to discuss as a function of impulsive index(A), Gaussian noise to impulsive noise power ratio($\Gamma$'), multi access interference(Κ), Nakagami fading parameter(m), the number of diversity branch (Ｌ), the number of error correction symbol (t), PN code sequence length(N) and $E_b/N_0$. The error performance of DS/CDMA-MDPSK signals improve by adopting MRC diversity and BCH(15,7) coding technique in the environment of impulsive noise plus Nagakami fading. From the results, we known that proposed system is affected by multi access interference, impulsive noise and Nakagami fading in radio communication system environment. Also, BER performance of DS/CDMA DQPSK communication system cam be improved increasing either the power of desired signal or the value of Gaussian noise to impulsive noise power ratio. And BCH(15,7) code technique is more effective to restrain the affection of multi access, interference, impulsive noise and Nakagami fading in DS/CDMA DQPSK communication system than MRC diversity reception technique.

• Journal of Korea Game Society
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• v.10 no.6
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• pp.157-168
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• 2010

A terrain is an essential element for constructing a virtual world in which game characters and objects make various interactions with one another. Creating a terrain requires a great deal of time and repetitive editing processes. This paper presents a 3D terrain reconstruction system to create 3D terrain in virtual space based on real terrain data. In this system, it converts the coordinate system of the height maps which are generated from a stereo camera and a laser scanner from global GPS into 3D world using the x and z axis vectors of the global GPS coordinate system. It calculates the movement vectors and the rotation matrices frame by frame. Terrain meshes are dynamically generated and rendered in the virtual areas which are represented in an undirected graph. The rendering meshes are exactly created and updated by correcting terrain data errors. In our experiments, the FPS of the system was regularly checked until the terrain was reconstructed by our system, and the visualization quality of the terrain was reviewed. As a result, our system shows that it has 3 times higher FPS than other terrain management systems with Quadtree for small area, improves 40% than others for large area. The visualization of terrain data maintains the same shape as the contour of real terrain. This system could be used for the terrain system of realtime 3D games to generate terrain on real time, and for the terrain design work of CG Movies.

• Journal for History of Mathematics
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• v.25 no.1
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• pp.71-88
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• 2012

The purpose of this study is to find the way to build the concept image about natural logarithm and the method is using definite integral in calculus under GeoGebra environment. When the students approach to natural logarithm, need to use dynamic program about the definite integral in calculus. Visible reasoning process through using dynamic program(GeoGebra) is the most important part that make the concept image to students. Also, for understand mathematical concept to students, using GeoGebra environment in dynamic program is not only useful but helpful method of teaching and studying. In this article, about graph of natural logarithm using the definite integral, to explore process of understand and to find special feature under GeoGebra environment. And it was obtained from a survey of undergraduate students of mathmatics. Also, relate to this process, examine an aspect of students, how understand about connection between natural logarithm and the definite integral, definition of natural logarithm and mathematical link of e. As a result, we found that undergraduate students of mathmatics can understand clearly more about the graph of natural logarithm using the definite integral when using GeoGebra environment. Futhermore, in process of handling the dynamic program that provide opportunity that to observe and analysis about process for problem solving and real concept of mathematics.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.141-148
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• 2011

Most of the previous works on scene change detection algorithm focus on the detection of abrupt rather than gradual changes. In general, gradual scene change detection algorithms require heavy computation. Some of those approaches don't consider the error factors such as flashlights, camera or object movements, and special effects. Many scenes change detection algorithms based on the histogram show better performances than other approaches, but they have computation load problem. In this paper, we proposed a scene change detection algorithm with fast and accurate performance using the vertical and horizontal blocked slice images and their macro block informations. We apply graph cut partitioning algorithm for clustering and partitioning of video sequence using generated spatio-temporal histogram. When making spatio-temporal histogram, we only use the central block on vertical and horizontal direction for performance improvement. To detect camera and object movement as well as various special effects accurately, we utilize the motion vector and type information of the macro block.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.3
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• pp.201-207
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• 2021

Deep learning, a type of machine learning, performs learning while changing the weights as it progresses through each learning process. Tensor Flow and Keras provide the results of the end of the learning in graph form. Thus, If an error occurs, the result must be discarded. Consequently, existing technologies provide a function to roll back learning results, but the rollback function is limited to results up to five times. Moreover, they applied the concept of MLOps to track the deep learning process, but no rollback capability is provided. In this paper, we construct a system that manages the intermediate value of the learning process by blockchain to record the intermediate learning process and can rollback in the event of an error. To perform the functions of blockchain, the deep learning process and the rollback of learning results are designed to work by writing Smart Contracts. Performance evaluation shows that, when evaluating the rollback function of the existing deep learning method, the proposed method has a 100% recovery rate, compared to the existing technique, which reduces the recovery rate after 6 times, down to 10% when 50 times. In addition, when using Smart Contract in Ethereum blockchain, it is confirmed that 1.57 million won is continuously consumed per block creation.

• Journal of The Korean Association For Science Education
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• v.27 no.5
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• pp.404-411
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• 2007

The purpose of this study was to examine the types of explanation about different experimental data on students' preconceptions on physical experiment. 45 students were selected from P University by examining their pre-test. The subjects had a scientific conception about a simple pendulum's period of movement, and expected that there was no change in the movement even when the mass of water increased in the can. The students were presented data about pendulum movement inside a can. They recorded this in a blank table and drew a graph about the movement of the pendulum. The responses of students were tested by presenting written anomalous experimental data. Students' recognition, trust about the anomalous data, cognitive conflict, belief change about their preconceptions were examined with written tests also. To measure students' cognitive conflict levels, CCLT (Cognitive Conflict Levels Test) developed in a previous study was used. Some students responded based on preconceptions and regarded the data as manufactured data or experimental error. The students who recognized the anomaly in the situation showed higher cognitive conflict levels than those who didn't recognize the anomaly in the situation. The students who changed their beliefs about preconceptions recognized the data as anomalous situations and showed high cognitive conflict levels than those who didn't abandon their preconceptions. The students who have unchanged beliefs about their preconceptions regarded the data as experimental error.

• The Journal of the Korea Contents Association
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• v.9 no.12
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• pp.77-85
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• 2009

As the multimedia technology has become in popular, many software packages that are for using those multimedia contents have also been developed. Directshow is a media framework which makes the development of such multimedia software simple, quick and regular process. In the Directshow, data are processed through the connections between filters. In general, Filtergraph is utilized to be set as 'Intelligent Connection' for filter connection. However, when we use this 'Intelligent Connection' option, they can show non-expected results or fail to connect with filter's pins together. So in this paper, we propose non-necessary filter cut-off method for connecting only just wanted filters. There are two methods such as inner filter cut-off method and outer filter one. The inner filter cut-off method is good at connection's compatibility and able to quickly connect with each other filter. But in the outer filter cut-off method, filter source is not necessary and connection is exactly done with other filter. In the end, we propose Directshow based filter cut-off model which compose of wanted filter connection and minimize error probability, through mixing up the advantages of two filter cut-off methods.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.177-193
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• 2018

The business process management system that can integrate and manage a medical institution's processes has been increased importance to adapt to constantly changing medical environments and share information with various external medical institutions. The business process management system is an automated process tool that converts the graphic-based BPMN process model into a WS-BPEL, the execution language of the web service environment, and executes it through the process engine. However, the BPMN process model can be difficult to convert into WS-BPEL due to several ambiguities and structural inconsistencies. The process model may also contain structural anomalies that can lead to execution errors during process execution. In this paper, we present business process model formalization and structural anomaly verification techniques for facilitating integrated process management in medical institutions. Through the case study based on the IHE profile, we presented a formalized BPMN process model and verify the structural anomalies. We show the superiority of the proposed technique through comparative experiments with other related works.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.4
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• pp.138-149
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• 2018

In this paper, we propose a system model which effectively mitigates impulsive noise that degrades the performance of power line communication. Recently, deep learning have shown effective performance improvement in various fields. In order to mitigate effective impulsive noise, we applied a convolution neural network which is one of deep learning algorithm to conventional system. Also, we used a successive interference cancellation scheme to mitigate impulsive noise generated from multi-users. We simulate the proposed model which can be applied to the power line communication in the Section V. The performance of the proposed system model is verified through bit error probability versus SNR graph. In addition, we compare ZF and MMSE successive interference cancellation scheme, successive interference cancellation with optimal ordering, and successive interference cancellation without optimal ordering. Then we confirm which schemes have better performance.