• 한국경영과학회지
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• 제33권2호
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• pp.27-44
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• 2008

Owl-based ontology is useful to realize the context-aware services which are composed of the distributed and self-configuring modules. Many ontology-based inference engines are developed to infer useful information from ontology. Since these engines show the uniqueness in terms of speed and information richness, it's difficult to ensure stable operation in providing dynamic context-aware services, especially when they should deal with the complex and big-size ontology. To provide a best inference service, the purpose of this paper is to propose a novel methodology of context-aware engine selection in a contextually prompt manner Case-based reasoning is applied to identify the causality between context and inference engined to be selected. Finally, a series of experiments is performed with a novel evaluation methodology to what extent the methodology works better than competitive methods on an actual context-aware service.

• 한국수학교육학회지시리즈E:수학교육논문집
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• 제37권3호
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• pp.545-567
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• 2023

본 연구는 이차방정식과 이차함수 단원을 중심으로 수학 문제 해결에 효과적인 ChatGPT의 프롬프트를 고찰하는 연구로 '역할-규칙-예제풀이-문제-과정'으로 이어지는 구조화된 프롬프트를 설계하였다. 본 연구에서는 GPT4, 울프람 플러그인, Advanced Data Analysis를 결합한 인공지능 모델을 활용하였으며, 계산 오류를 줄이기 위해 울프람 플러그인을 주요 연산의 도구로 사용하였다. 9종의 고등학교 수학 교과서의 이차방정식과 이차함수 단원 문제를 구조화된 프롬프트의 형태로 입력하였을 때 ChatGPT의 답변에 대한 정답률은 91%로, 제로샷 프롬프트 대비 높은 성과를 보였다. 이를 통해 수학 문제 해결에 효과적인 구조화된 프롬프트를 확인할 수 있었다. 본 연구에서 설계한 구조화된 프롬프트는 개별화 교육 및 맞춤형 교육을 위한 지능형 정보시스템 구축에 기여할 수 있을 것이다.

• 동력기계공학회지
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• 제9권4호
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• pp.155-161
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• 2005

Governors control the revolution speed of heat engines such as diesel engines, steam turbines and gas turbines. Precise and prompt tests for the control performances of governors are essential both in governors' manufacturing processes and in governors' maintenance processes. In the conventional governor test systems controlled by analog type electronic controllers, the incorporation of heat engine's dynamics to the test system have been considered very difficult to realize. This study suggests a new governor test system controlled by a digital controller using a personal computer. The application of the digital controller to the test system instead of the analog type electronic controller have brought about the following advancements; (1) heat engine's dynamics could be implemented easily in the test system, (2) automatic test data acquisition both in steady state and in transient state enables us to save test time and to enhance the reliability of the tests.

• 한국자동차공학회논문집
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• 제11권5호
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• pp.22-28
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• 2003

Flash boiling mechanism in the injector interferes with fine fuel metering in a liquid phase LPG injection engine. This study presents a mathematical model to precisely predict an injection quantity. A calibration procedure of injection quantity, which is very prompt and precise in measuring, is developed using a gas analyzer. According to this procedure, injection quantity can be obtained under various fuel compositions, temperatures and injection pressures. The release pressure of liquid phase LPG is estimated based on these experimental data. Although the release pressure is much lower than the saturation pressure, it is linearly proportional to the saturation pressure.

• 대한산업공학회지
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• 제24권3호
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• pp.397-406
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• 1998

The purpose of this research is to develop an integrated quality inspection system using machine vision technology in the automotive engine assembly process. The system makes it possible for the inspected data to be entered directly from the machine vision system into the developed system without the need for intermediate operations. Such direct entry enables prompt corrective actions against process problems. An IVP-150 machine vision board is installed an the PC for image processing, and a template matching technology is implemented to precisely verify quality factors. The developed system is successfully installed in a manufacturing process, and it showed robustness to the problems of noise, distortion, and orientation.

• Journal of Mechanical Science and Technology
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• 제16권7호
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• pp.1009-1018
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• 2002

The Representative Interactive Flamelet (RIF) concept has been applied to numerically simulate the combustion processes and pollutant formation in the direct injection diesel engine. Due to the ability for interactively describing the transient behaviors of local flame structures with CFD solver, the RIF concept has the capabilities to predict the auto-ignition and subsequent flame propagation in the diesel engine combustion chamber as well as to effectively account for the detailed mechanisms of soot formation, NOx formation including thermal NO path, prompt and nitrous 70x formation, and reburning process. Special emphasis is given to the turbulent combustion model which properly accounts for vaporization effects on the mixture fraction fluctuations and the pdf model. The results of numerical modeling using the RIF concept are compared with experimental data and with numerical results of the commonly applied procedure which the low-temperature and high-temperature oxidation processes are represented by the Shell ignition model and the eddy dissipation model, respectively. Numerical results indicate that the RIF approach including the vaporization effect on turbulent spray combustion process successfully predicts the ignition delay time and location as well as the pollutant formation.

• 한국산업정보학회논문지
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• 제4권3호
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• pp.71-78
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• 1999

이 논문은 영상처리기법을 이용하여 자동차 엔진 조림공정에 대한 통합적인 자동검사시스템의 개발에 관한 연구이다. 본 시스템은 머신비전에 의한 검사데이터를 통계적 공정관리시스템으로 직접 입력이 가능하며, 이러한 특성은 품질 이상이나 공정에 문제가 발생하였을 때 즉각적인 수정 조치가 가능한 기술이다. 검사부분에 대한 영상처리는 PC 내부에 설치되어 있는 IVP-150 머신비전 보드에 의하여 이루어지며, 품질요소를 정확히 확인하기 위해 템플리트 매칭 기술이 적용되었다. 본 시스템을 생산현장에 적용한 결과, 잡음이나 영상의 삐뚤어짐 흑은 방향성 등의 문제에도 적응력이 강함이 입증되었다.

• 천문학회보
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• 제43권1호
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• pp.39.2-39.2
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• 2018

GW170817/GRB170817A establishes a double neutron star merger as the progenitor of a short gamma-ray burst, starting 1.7 s post-coalescence. GRB170817A represents prompt or continuous emission from a newly formed hyper-massive neutron star or black hole. We report on a deep search for broadband extended gravitational-wave emission in spectrograms up to 700 Hz of LIGO O2 data covering this event produced by butterfly filtering comprising a bank of templates of 0.5 s. A detailed discussion is given of signal-to-noise ratios in image analysis of spectrograms and confidence levels of candidate features. This new pipeline is realized by heterogeneous computing with modern graphics processor units (GPUs). (Based on van Putten, M.H.PM., 2017, PTEP, 093F01.)

• 천문학회보
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• 제43권1호
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• pp.39.1-39.1
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• 2018

Although it is agreed that the gamma-ray bursts (GRBs) invoke highly relativistic jets with bulk Lorentz factors of a few hundreds, the exact physical mechanism producing such powerful gamma-rays still remains debated. Three outstanding and important questions in the field concern (1) the composition of GRB jets (i.e., matter-dominated vs Poynting-flux-dominated), (2) the involved radiative process responsible for the observed gamma-rays (i.e., synchrotron mechanism vs photospheric radiation), and (3) the distance of the emitting region from the central engine where the prompt gamma-rays are released (i.e., ~10^12 cm vs 10^14 cm vs 10^16 cm). I will present recent important breakthroughs that we have made, which answer these three questions.

• Journal of Astronomy and Space Sciences
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• 제33권4호
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• pp.247-256
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• 2016

An analysis of light curves and spectra of observed gamma-ray bursts in gamma-ray ranges is frequently demanded because the prompt emission contains immediate details regarding the central engine of gamma-ray bursts (GRBs). We have revisited the relationship between the collimation-corrected peak luminosity and the spectral lag, investigating the lag-luminosity relationships in great detail by focusing on spectral lags resulting from all possible combinations of channels. Firstly, we compiled the opening angle data and demonstrated that the distribution of opening angles of 205 long GRBs is represented by a double Gaussian function having maxima at ~ 0.1 and ~ 0.3 radians. We confirmed that the peak luminosity and the spectral lag are anti-correlated, both in the observer frame and in the source frame. We found that, in agreement with our previous conclusion, the correlation coefficient improves significantly in the source frame. It should be noted that spectral lags involving channel 2 (25-50 keV) yield high correlation coefficients, where Swift/Burst Alert Telescope (BAT) has four energy channels (channel 1: 15-25 keV, channel 2: 25-50 keV, channel 3: 50-100 keV, channel 4: 100-200 keV). We also found that peak luminosity is positively correlated with peak energy.