• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.56-61
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• 2008

Because the harmonic disturbance characteristic which makes voltage drop and the deterioration of instantaneous power quality in electrical power system overheats the NGR and the customer capacitor and malfunctions the OCGR and AMR, it is necessary for electric power company to take active measures to reduce this disturbance. International Electrotechnical Commission(IEC) 61000-3-2 specifies limits for harmonic current emissions generated by low voltage(LV) electrical equipment whose input current $\leq$ 16(A) per phase. Analysis shows that limits for Class A equipment in IEC are calculated using the reference impedance of LV system and maximum permissible voltage and limits for other Classes are also calculated based on limits for Class A. Therefore we have calculated four(4) internal limits for LV electrical equipment using the korea reference impedance and maximum permissible voltage in this paper.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.7
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• pp.550-559
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• 2018

The effectiveness of deep neural networks (DNNs) for detection and classification of micro-Doppler signals generated by human walking and background noise sources is investigated. Previous research included a complex process for extracting meaningful features that directly affect classifier performance, and this feature extraction is based on experiences and statistical analysis. However, because a DNN gradually reconstructs and generates features through a process of passing layers in a network, the preprocess for feature extraction is not required. Therefore, binary classifiers and multiclass classifiers were designed and analyzed in which multilayer perceptrons (MLPs) and DNNs were applied, and the effectiveness of DNNs for recognizing micro-Doppler signals was demonstrated. Experimental results showed that, in the case of MLPs, the classification accuracies of the binary classifier and the multiclass classifier were 90.3% and 86.1%, respectively, for the test dataset. In the case of DNNs, the classification accuracies of the binary classifier and the multiclass classifier were 97.3% and 96.1%, respectively, for the test dataset.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.300-312
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• 2000

The application areas of embedded real-time systems are very wide and so are the requirements for real-time processing and reliability of the systems. To develop embedded real-time systems effectively with its real-time and reliability properties guaranteed, an appropriate real-time model is needed. Recently, the research on real-time object-oriented model is active, which graft the concept of object-orientation on real-time systems modeling and development. In this paper, we propose dRTO (dependable Real-Time Object) model, with 5 primitive classes. These allow designers to effectively model the characteristics of real-time systems, i.e., object-orientation, real-time-ness and dependability. The dRTO model has three main features. First, it is able to model and implement the timing constraints imposed on real-time objects as well as interactions among the objects. Second, hardware and software components (including kernel) of embedded systems can be modeled in one frame. Third, it is able to represent fault detection and recovery mechanisms explicitly.

• Journal of computational fluids engineering
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• v.9 no.2
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• pp.1-10
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• 2004

In the present study, a post-processing program is developed for 3D data visualization and analysis. Because the graphical user interface(GUI) of the program is based on Qt-library while all the graphic rendering is performed with OpenGL library, the program runs on not only MS Windows but also UNU and Linux systems without modifying source code. The structure of the program is designed according to the object-oriented programming(OOP) concept so that it has extensibility, reusability, and easiness compared to those by procedural programming. The program is organized as modules by classes, and these classes are made to function through inheritance and cooperation which is an important and valuable concept of object-oriented programming. The major functions realized so far which include mesh plot, contour plot, vector plot, streamline plot, and boundary plot are demonstrated and the relevant algorithms are described.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.6
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• pp.1501-1509
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• 1996

Mobile stations can be classified by the transmission power level in CDMA system. Different performance parameters will be given to each class of mobile stations so that the appropriate quality ofservices can be provided. In this paper, it is assumed that there are two clsses of mobile stations. with the classification of mobile stations, analytical models are presented for the estimates of the reverse link capacity and the blocking probability. From the model for the reverse link capacity, the maximum number of each class of mobile stations to be served is derived. It is shown that $E_{b/}$I reduction of 1 dB allows the capacity to be increased by 25% and the data transmission rate and the power control accuracy have a significant effect on the reverse link capacity and the blocking probability. Simulation results are provided for validating the anlaytical estimates of the blocking probability.ocking probability.y.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.163-164
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• 2018

본 논문에서는 양방향 예측 모드에서 LIC(Local Illuminance Compensation)의 복잡도 감소를 위한 방법을 제안한다. 제안하는 방법은 현재 CU 가 양방향 예측 모드일 경우 움직임 보상 단계에서 예측 블록 두 개를 가중 평균을 낸 뒤 LIC 를 수행함으로써 양방향 예측모드에서 LIC 를 한번만 수행하여 기존 LIC 대비 낮은 복잡도를 보인다. 제안하는 방법의 성능 평가를 위하여 RA(Random Access) 조건에서 MPEG 표준 실험 영상의 B, C, D 클래스를 이용하여 BD-rate 를 VTM-2.0.1 과 비교한다. 실험결과로서 본 논문에서 제안하는 방법이 VTM2.0.1 대비 BD-rate 성능 관점에서 Y, U, V 각각에 대하여 평균 0.17, 0.17, 0.23 의 성능 향상을 보인다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2021.07a
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• pp.15-16
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• 2021

본 논문에서는 RGB 영상 데이터를 입력으로 하여 mediapipe의 손 포즈 추정 알고리즘을 적용해 손가락 관절 및 주요 부위의 위치를 얻고 이를 기반으로 딥러닝 모델에 학습 후 손동작 인식 방법을 제안한다. 연속된 프레임에서 한 손의 손가락 주요 부위 간 좌표를 얻고 차분 벡터의 x, y좌표를 저장한 후 Conv1D, Bidirectional GRU, Transformer를 결합한 딥러닝 모델에 학습 후 손동작 인식 분류를 하였다. IC4You Gesture Dataset 의 한 손 동적 데이터 9개 클래스에 적용한 결과 99.63%의 손동작 인식 정확도를 얻었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.10
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• pp.2014-2027
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• 1994

A queueing model with two input streams of different service priorities is studied. Specifically, IBP+BP/D/1 with head-of-line priority is analyzed. IBP and BP stand for Interrupted Bernoulli Process and Bernoulli Process respectively. The BP-stream customers have the higher service priority over the IBP-stream customers. An exact analysis of this priority queue is presented to derive the distributions of the state of the system at steady state, the waiting time distributions for each class of customers, and the interdeparture time distributions. The numerical results of the analysis are presented to show how the various parameters of the low and high priority arrival processes affect the performance of the system.

• Journal of Korea Multimedia Society
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• v.8 no.4
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• pp.536-543
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• 2005

3D online game, with its striking realistic value, is leading the entire Korean game market which has various game genres. Technology sharing is very hard within the Korean game industry. That is because 1)there are few professionals, 2)most of the companies are small-scaled, and 3)there are security reasons. Therefore, it should be significant if we have software design techniques which make it possible to reuse the existing code when developing a network game so that we could save a lot of efforts. In this paper, the author analyzes the demand through the case in the client's design of the network game based on DirectX and proposes the effective software design methods for reusable code based on the creative patterns application in the GoF in the class design.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.10
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• pp.76-83
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• 2008

The neutral current is made of both the load unbalanced current and the 3rd harmonic. The 3rd harmonic which is the source of the main neutral current is generated from the loads using bridge rectifier circuits on their input produce currents. TV, computer and monitor which are belong to IEC 61000-3-2 Class D are the main 3rd harmonic current sources. In order to show the affect of the distribution system by these disturbances, this paper has studied the current standards of the Korea Electric and considers the problem of the neutral common.