• Clean Technology
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• v.23 no.1
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• pp.95-103
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• 2017

In this study, $ATiO_3$ (A = Ca, Sr, Ba) perovskite, which is the widely known for non $TiO_2$ photocatalysts, were synthesized using sol-gel method. And Ni was added at the A site of $ATiO_3$ by using that it is easy to incorporate. The physicochemical characteristics of the obtained $ATiO_3$ and Ni-$ATiO_3$ particles were confirmed using the X-ray diffraction (XRD) UV-visible spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), the $N_2$ adsorption-desorption isotherm measurement, and X-ray photoelectron spectroscopy (XPS). The $H_2$ was produced using the photolysis of MeOH. Using the Ni-$ATiO_3$ photocatalysts, $H_2$ production was higher than using the $ATiO_3$ photocatalysts. Especially, $273.84mmolg^{-1}$ $H_2$ was produced after 24 h reaction over the Ni-$SrTiO_3$. Also in the water (0.1 M KOH) with the Ni-$SrTiO_3$, $H_2$ production was $961.51mmolg^{-1}$ after 24 h reaction.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.2
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• pp.83-92
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• 2018

Using ground moving target indicators equipped with synthetic aperture radars for locating moving targets within a wide background clutter in a short time is an excellent method for monitoring traffic. Although the displaced phase center antenna (DPCA) technique and along track interferometry (ATI) are real time methods with low computational complexity, they are essential for reducing cases of false alarm that can result in poor performance. In this paper, we propose two detection methods using DPCA and ATI-the parallel fusion method and serial fusion method. Simulation results demonstrate that the proposed detection methods are characterized by low probability of false alarm along with good performance. In particular, the serial fusion method possesses high detection probability along with low probability of false alarm (1/5th of the false alarm probability of the DPCA technique).

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.5
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• pp.1153-1160
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• 2018

As the number of online game users increases and the market size grows, various kinds of cheating are occurring. Game bots are a typical illegal program that ensures playtime and facilitates account leveling and acquisition of various goods. In this study, we propose a method to detect game bots based on user action time interval (ATI). This technique observes the behavior of the bot in the game and selects the most frequent actions. We distinguish between normal users and game bots by applying Machine Learning to feature frequency, ATI average, and ATI standard deviation for each selected action. In order to verify the effectiveness of the proposed technique, we measured the performance using the actual log of the 'Aion' game and showed an accuracy of 97%. This method can be applied to various games because it can utilize all actions of users as well as character movements and social actions.

• Korean Journal of Materials Research
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• v.2 no.4
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• pp.248-256
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• 1992

This paper has reviewed some of the basic principles that underlie the field of defect chemistry in simple ATi$O_3$(A=Ca, Sr, Ba) perovskites. Frenkel defects in perovskite structure is very much unlikely, and Schottky defects and intrinsic electronic defects in undoped materials are negligibly small compared with background acceptor impurities. The electrical properties of perovskite ceramics are dependent on the aliovalent impurities. Since perovskite structure is a ternary system, the stoiohiometry between cations as well as cation-anion ratio will affect defect structure and electrical properties. BaTi$O_3$and SrTi$O_3$show a limited deviation from the cation stoichiometry while CaTi$O_3$has significant excess CaO and Ti$O_2$solubility.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.7
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• pp.560-570
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• 2017

Recently, well-known SAR imaging algorithms have been developed to form the focused SAR images for stationary targets. In general, the conventional methods exploit the range variation only defined by the motion of radar platform and SAR geometry. However, for SAR imaging of ground moving targets, the motion of the targets induces an additional range shift, yielding the blurred SAR images. To overcome the problem, in this paper we propose an effective motion compensation algorithm operated under a multi-channel SAR, named along-track interferometry(ATI) and phase unwrapping to directly estimate the motion parameters of the targets. In simulations, 50 Monte-Carlo simulation results show the effectiveness of the algorithm in the presence of noise.

• 한국연소학회:학술대회논문집
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• 2002.11a
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• pp.149-155
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• 2002

A promising new approach to achieve low pollutants emission and improvement of flame stabilities is tested experimentally using a hybrid cyclone jet combustor employing both premixed and diffusion combustion mode, Three kind of nozzles are used for LNG(Liquified Natural Gas) as a fuel. The combustor is operated by two method, One is ATI(Air Tangential Injection) mode, generated swirl flow by air as general swirl combustor, and the other is PTI(Premixed gas Tangential Injection) mode, The PTI mode consists of diffusion flame of axial direction and premixed cyclone flame of tangential direction in order to stabilized the diffusion flame. The results showed that the stable region of the PTI mode is more larger than the ATI mode. In addition, the reduction of NOx emission in PTI mode, as compared with that for the ATI mode is at least 50% in stable region. Also, even using the low calorific fuel as $CO_2$-blended gas, the cyclone jet combustor has high performance of flame stability.

• Journal of Industrial Technology
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• v.3
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• pp.27-32
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• 1983

This paper develops and provides formulas for calculating the Average Outgoing Quality and the Average Total Inspection for nine different sample/rest-of-lot disposition policies in which rectifying multiple sampling inspection by attribute can be carried out. The formulas are considered for perfect inspection as well as error-prone inspection.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.11C
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• pp.1076-1084
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• 2009

We propose an ATI (Adaptive Tone Injection) scheme based on clipping noise for PAPR (Peak-to-Average Power Ratio) reduction of OFDM (Orthogonal Frequency Division Multiplexing) signals. The proposed scheme is composed of three steps: clipping, tone selection, and TI procedures. In the first step, the peak samples in the IFFT (Inverse Fast Fourier Transform) outputs are scaled down by clipping. In the second step, the sub-carrier position where the power of the clipping noise is the maximum, is selected. Finally, the generic TI procedure is performed. Simulation results show that the proposed scheme does not require all the possible combinations of the original TI procedures, while maintaining the PAPR reduction performance.

• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.82-86
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• 1999

For nonconducting perovskite titanates ATiO3 and A'1/2A"1/2TiO3, 5 ferroelectric members were discriminated from 17 quantum paraelectric members via average mass of A ions m(A): ferroelectric for m(A)〉110 a.u. and quantum paraelectric for m(A)<100 a.u. An intuitive explanation of the origin of the discrimination is given concenrned with the ferroelectric soft modes in perovskite ATiO3. Based on the above discrimination, trial synthesis of ferroelectric candiate substances are presented.

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.183-191
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• 2002

본 논문은 ATIS의 효과를 평가할 수 있도록 교통정보제공에 따른 운전자의 노선선택 행태자료를 수집할 수 있는 시뮬레이터 개발에 관한 것이다. 현재 이러한 행태자료를 수집하기 위해서 설문지에 의한 SP(Stated Preference) 설문조사가 널리 수행되어지고 있으나 이러한 설문조사방법은 ATIS와 같은 가상의 환경을 응답자에게 이해시킬 수 있는 설문지를 작성하기가 힘들고, 무엇보다 운전중에 느끼게 되는 time pressure를 현실적으로 반영하지 못하기 때문에 신뢰성있는 자료를 수집하는데 어려움이 있다. 시뮬레이터는 보다 현실적인 교통상황을 계산하고 적절한 인터페이스 구성을 통해 교통상황과 분석자의 설문 의도를 응답자에게 효과적으로 인지시킬 수 있다는 장점을 가지고 있다. 본 연구에서 세 가지 모듈(교통 시뮬레이션 모듈, 데이터베이스 모듈, 이용자 인터페이스 모듈)로 구성된 프로토타입 시뮬레이터를 개발하였다. 개발된 프로토타입의 유용성을 알아보기 위해 실제로 실시간 교통정보가 제공되는 작은 네트워크를 대상으로 파일럿 테스트를 수행하였고, 수집된 자료는 discrete choice model을 정산하는데 사용하였으며 그 분석결과는 상당히 합리적인 것으로 나타났다. 따라서, 이러한 시뮬레이터는 교통정보전략에 따른 효과를 사전에 분석해보고, 효과적인 교통정보시스템을 설계 및 운영하는데 활용될 수 있을 것이다.