• International Journal of Aeronautical and Space Sciences
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• 제13권3호
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• pp.377-385
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• 2012

The Automatic Dependent Surveillance Broadcast (ADS-B) system is a key component of CNS/ATM recommended by the International Civil Aviation Organization (ICAO) as the next generation air traffic control system. ADS-B broadcasts identification, positional data, and operation information of an aircraft to other aircraft, ground vehicles and ground stations in the nearby region. This paper explores the ADS-B based trajectory prediction and the conflict detection algorithm. The multiple-model based trajectory prediction algorithm leads accurate predicted conflict probability at a future forecast time. We propose an efficient and accurate algorithm to calculate conflict probability based on approximation of the conflict zone by a set of blocks. The performance of proposed algorithms is demonstrated by a numerical simulation of two aircraft encounter scenarios.

• 한국수자원학회논문집
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• 제37권1호
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• pp.67-75
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• 2004

본 연구에서는 홍수시 다목적댐의 효율적 운영을 위하여 상류로부터 유입되는 홍수유입량을 실시간으로 예측하기 위해 역전파 신경망 모형을 사용하여 댐유입량 예측모형(Neural Dam Inflow Forecasting Model; NDIFM)을 개발하였다. NDIFM은 다목적댐에 의한 하류의 홍수조절 비중이 큰 낙동강의 남강댐 유역에 적용하였으며, 입력자료로는 댐유역 평균강우량, 실측 댐유입량, 예측 댐유입량 통을 사용하여 실시간 댐유입량 예측의 가능성을 검토하였다. 실측치와 예측치를 비교ㆍ검토한 결과 제시한 세 가지 모형 중 NDIFM-I이 가장 우수한 결과를 나타내었으며, NDIFM-II 및 NDIFM-III 또한 다양한 예측가능성을 보여주었다. 따라서, 강우-유출의 비선형시스템 모의를 위하여 물리적 매개변수가 복잡한 개념적 모형보다는 양질의 수문관측 자료만 축적된다면 블랙박스 모형인 신경망 모형이 실시간 홍수예측에 효율적으로 활용될 수 있을 것이다.

• 전자공학회논문지A
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• 제29A권3호
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• pp.96-105
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• 1992

The use of fixed-point digital signal processors, such as the TMS 320C25, requires scaling of data at each arithmetic step to prevent overflows while keeping the accuracy. A software which automatizes this process is developed for TMS 320C25. The programmers use a model of a hypothetical floating-point digital signal processor and a floating-point format for data representation. However, the program and data are automatically translated to a fixed-point version by this software. Thus, the execution speed is not sacrificed. A fixed-point variable has a unique binary-point location, which is dependent on the range of the variable. The range is estimated from the floating-point simulation. The number of shifts needed for arithmetic or data transfer step is determined by the binary-points of the variables associated with the operation. A fixed-point code generator is also developed by using the proposed automatic scaling software. This code generator produces floating-point assembly programs from the specifiations of FIR, IIR, and adaptive transversal filters, then floating-point programs are transformed to fixed-point versions by the automatic scaling software.

• 유통과학연구
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• 제14권10호
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• pp.93-107
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• 2016

Purpose - This study aims to derive directions and implications for improving performance in operating agrifood export organizations by identifying significant performance impact factors. Research design, data, and methodology - A seemingly unrelated regression (SUR) model was estimated using data from a survey conducted among 120 exporters including 16 leading export organizations. In the SUR estimation, the export volume and price are used as dependent variables and securing the quantity of products ordered and exported, quality management, and marketing activities are considered as explanatory variables for the operation performance. Results - The amount of farmer education, the manpower in charge of marketing, and the interaction terms between whether or not they belong to a leading export organization and the item dummy for mushrooms have a significant impact on the export volume where the export volume is specified as a dependent variable. The export volume is greater with a greater amount of farmer education and greater manpower in charge of marketing from the perspective of quality management. When the export price is estimated as a dependent variable, the manpower in charge of marketing is shown to have a significant impact on the export price. Conclusions - The government needs to strengthen its support of the performance of agrifood export organizations. The analysis indicates that the education of and consulting with farmers, and the manpower number in charge of marketing are key factors in the operation performance of export organizations. Therefore, supporting the export organizations in expanding their human resources in charge of marketing can increase the export volumes for agrifoods. Given, however, that the export volume associated with joint payments, human resources specialized in quality management, and the amount of participation in export exhibitions are not significant factors, it is essential to improve the supporting policies for those areas. The manpower in charge of marketing from the perspective of marketing has a significant impact on both the export volume and export price. Thus, we identify this as the most important category that should be supported to enhance performance in export organizations.

• 한국전기전자재료학회논문지
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• 제14권4호
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• pp.274-280
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• 2001

This paper presents transconductance (g$\_$m/( characteristics of GaAs MESFET's at high temperatures ranging from room temperature to 350$\^{C}$. GaAs MESFET of 0.3x750[㎛] gate dimension has been used to obtain the experimental data. Gate to source voltage(V$\_$GS/) has been controlled to obtain the temperature dependent characteristics for maximum transconductance g$\_$mmax/ of the device. Furthermore g$\_$mmax/ and expected g$\_$m/ have been traced with temperatures ranging from room temperature to 350$\^{C}$ also by compensating for C$\_$GS/ to maintain the optimum operation of the device. From the results, V$\_$GS/decreases as the operating temperature increases for optimum operation of the transconductance. Finally V$\_$GS/ has been optimized to trace g$\_$mmax/ and enhances the decreased g$\_$m/ with different temperatures.

• 한국항공운항학회지
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• 제20권2호
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• pp.26-31
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• 2012

A new operational concept for the CNS/ATM using the digital data communication technology and satellite navigation system is being implemented globally and the United States is the first country to apply UAT ADS-B system for general aviation. Korea also has plan to build ADS-B system for aeronautical surveillance to monitor low altitude flight of light aircraft and ultra-light flying device and the research to develop UAT ADS-B equipment is being carried out. This paper presents the application method of UAT ADS-B to support test operation with case study of foreign UAT ADS-B operation and survey of domestic environment.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(1)
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• pp.505-508
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• 2000

The success of target reconstruction in SAR(Synthetic Aperture Radar) imaging system is greatly dependent on the coherent detection. Primary causes of incoherent detection are uncompensated target or sensor motion, random turbulence in propagation media, wrong path in radar platform, and etc. And these appear as multiplicative phase error to the echoed signal, which consequently, causes fatal degradations such as fading or dislocation of target image. In this paper, we present iterative phase error estimation scheme which uses echoed data in all temporal frequencies. We started with analyzing wave equation for one point target and extend to overall echoed data from the target scene - The two wave equations governing the SAR signal at two temporal frequencies of the radar signal are combined to derive a method to reconstruct the complex phase error function. Eventually, this operation attains phase error correction algorithm from the total received SAR signal. We verify the success of the proposed algorithm by applying it to the simulated spotlight-mode SAR data.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2027-2032
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• 2005

This paper demonstrates details of thermal behavior of Langmuir-Blodgett (LB) film of poly(tert-butyl methacrylate) (PtBMA) by using the principal component analysis based two-dimensional correlation spectroscopy (PCA2D) through eigenvalue manipulating transformation (EMT). By uniformly lowering the power of a set of eigenvalues associated with the original data, the smaller eigenvalues becomes more prominent and the subtle contribution from minor components is now highlighted much more strongly than the original data. Thus, the subtle difference of thermal behavior of LB film of PtBMA from minor components, which is not readily detectable in the conventional 2D correlation analysis, is much more noticeable than the original data. PCA2D correlation spectra with EMT operation for the temperature-dependent IR spectra of LB film of PtBMA reveal the hidden property of phase transition processes during heating.

• Corrosion Science and Technology
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• 제5권3호
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• pp.99-105
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• 2006

This paper is to investigate feasibility on quantitative aging state of epoxy coating on concrete wall in containment structure under operation of nuclear power plants. For evaluating the physical characteristics of the epoxy coating, adhesion strengths of two kinds of degraded epoxy coating systems on both steel surfaces and concrete surfaces were measured via accelerated aging. Comparatively impedance data taken by ultrasonic test were also taken to relate with adhesion data. After aging, in case of concrete, from half of specimens, aging of epoxy coating was developed. As for steel, on $4^{th}$ inspection day, adhesion force was failed. To improve reliability on quality degradation of epoxy, relationship between adhesion and impedance was analyzed. By tracing to co-respond to these data, it was possible to Fig. out physical state of as-built epoxy coating. The possibility to develop new methodology of time - dependent aging state on epoxy coating was found and discussed.

• 한국재난정보학회 논문집
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• 제16권2호
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• pp.343-352
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• 2020

연구목적: 본 연구는 소방공무원의 지진재난 대응을 위한 소방조직구성, 소방지휘능력, 여론운영 등이 조직시민행동에 미치는 영향을 파악하여 소방조직이 지진재난에 대응하기 위한 실무적 기초자료를 제공하는데 목적이 있다. 연구방법: 전국 소방공무원 159명을 대상으로 설문조사를 수행하였으며, 조사자료는 SPSS 22.0 프로그램을 이용하여 통계적 분석을 수행하였다. 연구결과: 첫째, 소방조직구성, 소방지휘능력, 여론운영 등은 조직시민행동에 정(+)의 영향을 미치는 것으로 나타났다. 둘째, 독립변인의 종속변인에 대한 상대적 기여도는 소방조직구성, 소방지휘능력, 여론운영 순서로 확인되었다. 결론: 본 연구의 분석결과를 통해 정부가 지진대응을 위해 사전에 소방조직 구성, 소방지휘능력 배양, 여론운영이 필요함을 실무적 관점에서 제시하고자 하며 향후 발생할 수 있는 재난에 대비하고자 하는 기초자료로 활용되길 기대해 본다.