• Journal of the Korea Society of Computer and Information
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• v.26 no.2
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• pp.53-60
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• 2021

In this paper, we aimed to identify the insulation characteristics and reliability of Epoxy composites, which are widely used as insulation material for electrical & electronic components and electric appliance. To this end, it was necessary to predict variations of electric field due to the distribution of fillers that must be added by economic and mechanical factors. So, we verified the result using an electric field analysis Simulator. Furthermore, under the condtion of DC voltage application, an dielectirc breakdown test was performed according to ambient temperature changes and the distribution of fillers, and the changes were observed. Three types of specimens were manufactured by adding 0, 50 and 100[phr] filling to Epoxy resin. In all specimens, as temperature was increased, the strength of the dielectric strength was decreased. When comparing the simulation results with the actual dielectric breakdown test results, we was able to confirm the technical applicability required for Insulation design of electric appliance.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.355-361
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• 2002

본 연구에서는 원적외선.열풍 복합건조특성을 구명하기 위하여 건조용량 150-500kg이고, 승강기, 상.하부스크류, 건조실, 템퍼링실, 송풍기 및 가열장치로 구성된 시뮬레이터를 제작하여 건조특성시험을 실시하였다. 그 결과를 요약하면 다음과 같다. 가. 열풍온도에 따른 곡온변화를 시험한 결과 열풍온도 45$^{\circ}C$일 때 곡온 32-33$^{\circ}C$를 유지하였으며, 48, 51$^{\circ}C$일 때는 곡온이 35$^{\circ}C$가 넘어서는 현상을 나타났다. 건조중 곡온이 35$^{\circ}C$를 넘어서게 되면 동할미 발생량이 많아지고 품질저하가 급격히 일어난다. 나. 템퍼링실의 온도편차가 2,5$^{\circ}C$ 정도로 고른 온도분포를 나타내었고, 버너 입구쪽과 템퍼링실 중앙지점에서 온도가 약간 높게 나타났으며, 원적외선방사체 표면온도분포는 열풍온도가 45$^{\circ}C$일 때 평균 17$0^{\circ}C$를 유지하였고, 48$^{\circ}C$, 51$^{\circ}C$일 때 각각 22$0^{\circ}C$, 23$0^{\circ}C$에서 유지하는 것으로 나타났다. 다. 원적외선방사체 길이방향으로 온도편차는 버너를 기준으로 해서 버너쪽에서 멀수록 온도가 높았고, 중간, 근거리 순으로 나타났다. 버너의 원거리쪽에서 온도가 높게 나타난 것은 원적외선방사체를 통과하는 열풍이 빠져나가도록 되어있는 열풍 유동관이 버너 원거리에 위치하고 있어 버너에 불꽃이 점화되면서 열풍이 방사체 끝쪽으로 일시 머물렀다가 배출되기 때문으로 판단된다. 라. 건조기의 송풍량을 요인으로 하여 건조속도와 건조에너지를 비교한 결과 송풍량이 30cmm일 때가 25cmm에서보다 약 33%의 건조속도가 증가되어 송풍량이 많을수록 건조속도가 빨라졌으나, 건조에너지는 1,391kcal/kg.water로 나타나 약 4.2%정도가 더 소요 되었다. 곡물순환속도를 요인으로 하여 비교 시험한 결과 곡물순환속도가 33kg/min일때가 26kg/min보다 약 25%의 건조속도가 증가되어 곡물의 순환속도가 빠를수록 건조속도가 빨라졌으며, 건조에너지도 1,334kcal/kg.water로 비슷하게 소요되었다. 마. 시험구와 대비구의 건감률은 시험구에서 1.08~1.36w.b./h로 나타나 대비구보다 약 9.9~18.3%가 높게 나타났고, 건조에너지는 10.2~14.6%가 절감되었다. 발아율은 열풍온도가 낮을수록 높게 나타났고 시험구가 대비구보다 발아율이 낮게 나타났으며, 동할률 증가량도 원적외선.열풍 복합건조방법이 높게 나타나 이것은 곡물 표면에 원적외선 방사에의한 복사열이 전달되어 열장해를 받았기 때문으로 판단되며, 금후 더 연구하여 적정 열풍온도 및 방사체 크기를 구명해야 할 것이다.

• The Journal of Korean Institute of Next Generation Computing
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• v.13 no.4
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• pp.29-39
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• 2017

Various electronic warfare situations drive the need to develop an integrated electronic warfare simulator that can perform electronic warfare modeling and simulation on radar threats. In this paper, we analyze the components of a simulation system to reversely model the radar threats that emit electromagnetic signals based on the parameters of the electronic information, and propose a method to gradually maintain the reverse extrapolation model of RF threats. In the experiment, we will evaluate the effectiveness of the incremental model update and also assess the integration method of reverse extrapolation models. The individual model of RF threats are constructed by using decision tree, naive Bayesian classifier, artificial neural network, and clustering algorithms through Euclidean distance and cosine similarity measurement, respectively. Experimental results show that the accuracy of reverse extrapolation models improves, while the size of the threat sample increases. In addition, we use voting, weighted voting, and the Dempster-Shafer algorithm to integrate the results of the five different models of RF threats. As a result, the final decision of reverse extrapolation through the Dempster-Shafer algorithm shows the best performance in its accuracy.

• Journal of Intelligence and Information Systems
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• v.23 no.2
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• pp.89-105
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• 2017

As the advances of technology in mobile networking and the popularity of online social networks (OSNs), the mobile social networks (MSNs) provide opportunities for marketing strategy. Therefore, understanding the information diffusion in the emerging MSNs is a critical issue. The information diffusion address a problem of how to find the proper initial nodes who can effectively propagate as widely as possible in the minimum amount of time. We propose a new diffusion scheme, called Hotspot DBC, which is to find k influential nodes considering each node's mobility behavior in the hotspot zones. Our experiments were conducted in the Opportunistic Network Environment (ONE) using real GPS trace, to show that the proposed scheme results. In addition, we demonstrate that our proposed scheme outperforms other existing algorithms.

• Journal of Engineering Education Research
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• v.3 no.1
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• pp.27-41
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• 2000

Recently there have been many Internet-based studies to provide personal users an efficient educational tool making use of multimedia data. The typical examples are remote education and virtual university where many educational trials on theory-based contents have been performed more frequently than those on experiment-based contents for engineering area. This paper describes about a base system implemented as an example of Internet-based experiment-oriented educations to establish cyber engineering laboratories for mechanics, electronics and chemistry. For the first time as a model of cyber engineering laboratories we herein Introduce in detail a server-and-client-based simulative method in which the result may be displayed on computer monitor of client PC while a simulator program is executed on the server. Secondly we introduce an interactive method in which the user of client PC may not only communicate directly with experiment server after initial connection with management server but also he can confirm the status of experiment being performed by way of video as well as experimental result.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.21-30
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• 2007

Simulation means modeling structures or behaviors of the various objects, and experimenting them on the computer system. And the major approaches are DEVS(Discrete Event Systems Specification). Petri-net or Automata and so on. But, the simulation problems are getting more complex or complicated these days, so that an intelligent agent-based is being studied. In this paper, we are describing an intelligent agent-based simulation tool, which can supports the simulation experiment more efficiently. The significances of our system can be described as follows. First, the system can provide some AI algorithms through the system libraries. Second, the system supports simple method of designing the simulation model, since it's been built under the Finite State Machine (FSM) structure. And finally, the system acts as a simulation framework by supporting user not only the simulation engine, but also user-friendly tools, such as modeler scriptor and simulator. The system mainly consists of main simulation engine, utility tools, and some other assist tools, and it is tested and showed some efficient results in the three different problems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.7
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• pp.831-841
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• 2010

The conventional vertical probe has the thin and long signal path that makes transfer characteristic of probe worse because of the S-shaped structure. So we propose the new vertical probe structure that has branch springs in the S-shaped probe. It makes closed loop when the probe mechanically connects to the electrode on a wafer. We fabricated the proposed vertical probe and measured the transfer characteristic and mechanical properties. Compared to the conventional S-shaped vertical probe, the proposed probe has the overdrive that is 1.2 times larger and the contact force that is 2.5 times larger. And we got the improved transfer characteristic by 1.4 dB in $0{\sim}10$ GHz. Also we developed the simulation model of the probe card by using full-wave simulator and the simulation result is correlated with measurement one. As a result of this simulation model, the cantilever probe and PCB have the worst transfer characteristic in the probe card.