• 항공우주시스템공학회지
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• 제1권2호
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• pp.6-12
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• 2007

Flight modes of automatic flight control system for light general aviation flight deck. Garmin G1000, were realized using Stateflow. In developing aircraft, it is difficult to verify the operational flight program in particular branch statement because developer can not see any visual logical steam. So, Stateflow has been used to visualize logical stream, transition from one flight mode to another flight mode. The performance was approved by applying flight mode transition conditions of G1000 to proposed transition system that is composed of states, switches, events, data and transition conditions. DURMI-II was used as 6-DOF simulation model.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.2623-2626
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• 2003

GPS provides two services which include SPS(Standard Positioning Service) and PPS(Precise Positioning Service). While SPS users can navigate in more precise due to cancellation of SA(Selective Availability), SPS users has still less precision navigation than PPS users. L1/L2CS integrated receiver can provide more precise navigation to SPS users because the delay of Ionosphere will be cancelled by using two frequencies (L1 and L2). This paper designs an integrated L1/L2CS digital correlator to prepare the L2C signal that will be provided in 2003. Also L2CS transmitter is designed to confirm L2CS correlator.

• 한국항공운항학회지
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• 제19권4호
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• pp.99-104
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• 2011

Pilots are exposed to carcinogenic substances like radiation, ozone, exhaust gas from jet engine, and electromagnetic wave, their environment can be very hazardous. I designed this study to know if there is any difference between pilots and general people in cancer incidence. I analyzed cancer cases between 1999 and 2008, and investigated their age, site, aircraft types, and sex. I compared pilot's cancer incidence with general people during same periods. Statistical analysis was performed with standardized incidence ratio (SIR). 10 cases were high performance pilots, 5 cases were low performance pilots. The average age when the diagnosis had been made was $39{\pm}7.8$. Pilot's incidence ratio was lower than people's, the most common cancer was kidney, and there was no lung cancer. Cancer is influenced by gene and environment, each country has different patterns. The low incidence ratio in Korean pilots might be due to "healthy worker effect". I think we should perform further investigation on kidney cancer.

• 대한수학회논문집
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• 제20권1호
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• pp.145-159
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• 2005

In this paper we consider the problem of testing statistical hypotheses for unknown parameters in nonlinear regression models and propose three asymptotically equivalent tests based on regression quantiles estimators, which are Wald test, Lagrange Multiplier test and Likelihood Ratio test. We also derive the asymptotic distributions of the three test statistics both under the null hypotheses and under a sequence of local alternatives and verify that the asymptotic relative efficiency of the proposed test statistics with classical test based on least squares depends on the error distributions of the regression models. We give some examples to illustrate that the test based on the regression quantiles estimators performs better than the test based on the least squares estimators of the least absolute deviation estimators when the disturbance has asymmetric and heavy-tailed distribution.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.425-436
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• 2015

This paper presents the procedures used for estimating the stability and control derivatives of a general aviation canard aircraft from flight data. The maximum likelihood estimation method which accounts for both process and measurement noise was used for the flight data analysis of a four seat canard aircraft, the Firefly. Without relying on the parameter estimation method, several aerodynamic derivatives were obtained by analyzing the steady state flight data. A wind tunnel test, a flight test of a 1/4 scaled remotely controlled model aircraft, and the prediction of aerodynamic coefficients using the USAF Stability and Control Digital Data Compendium (DATCOM), Advanced Aircraft Analysis (AAA), and Computer Fluid Dynamics (CFD) were performed during the development phase of the Firefly and the results were compared with flight determined derivatives of a full scaled flight prototype. A correlation between the results from each method could be used for the design of the canard aircraft as well as for building the aerodynamic database.

• 대한수학회지
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• 제43권3호
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• pp.623-634
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• 2006

Various methods have been studied to construct a fuzzy regression model in order to present a fuzzy relation between a dependent variable and an independent variable. However, in the fuzzy regression analysis the value of the center point of estimated fuzzy output may be either greater than the value of the right endpoint or smaller than the value of the left endpoint. In the case, we cannot predict the fuzzy output properly. This paper presents sufficient conditions to construct the fuzzy regression model using several methods investigated by some authors and then introduces the censored fuzzy regression model using the censored samples to manipulate the problem of crossing of the center and the end points of the estimated fuzzy number. Examples show that the censored fuzzy regression model is an extension of the fuzzy regression model and also it improves the problem of crossing.

• 한국항공운항학회지
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• 제22권1호
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• pp.15-21
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• 2014

Modern aircraft air navigation has been changed from the conventional air navigation aid to utilizing Global Navigation Satellite System. For the air navigation of fast moving aircraft, GNSS required extremely high accuracy and reliability. This study reviews the basic concept of Satellite Based Augmentation System which is discussed in the International Working Group of International Civil Aviation Organization and status of some SBAS leading State's case. In addition to that, a progress of SBAS development and implementation in the Republic of Korea was reviewed with pointing out of general hurdles and counter measures.

• 한국항공운항학회지
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• 제25권4호
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• pp.161-169
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• 2017

The Human Factors Analysis and Classification System (HFACS) is a general human error framework originally developed and tested within the U.S. military as a tool for investigating and analyzing the human causes of aviation accidents. Based upon Reason's (1990) model of latent and active failures, HFACS addresses human error at all levels of the system, including the condition of aircrew and organizational factors. As a result, this study aims to examine the influence between the latent conditions based on HFACS. This study seeks to verify the factors of "Organizational Influence" effecting the "Precondition for Unsafe Acts" of HFACS. The results of empirical analysis demonstrated that the organizational influence had a positive influence on precondition for unsafe act, especially the "Organizational Climate" of organizational influence had even greater influence on precondition for unsafe acts.

• 대한기계학회논문집A
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• 제20권1호
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• pp.180-188
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• 1996

The stress singularity of a sharp wedge contacting a half plane can be avoided by changing the wedge shape. Shape optimization is accomplished with the geometric strain method (GSM), an optimality criterion method. Several numerical examples are provided for different materials in the wedge and half plane to avoid stress singularity neal the sharp corner of the wedge. Optimum wedge shapes are obtained and critical corner angles are compared with the angles from analytical contact mechanics. Numerical results are well matched to analytical and experimental results. It is shown that shape optimization by the geometric strain method is a useful tool to reshape the wedge and to avoid a stress singulatiry. The method applies to more general geometries where the singular behavior would be difficult to avoid by classical means.

• 항공우주의학회지
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• 제29권2호
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• pp.59-66
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• 2019

Artificial Intelligence (AI) born in 1956 is a general term that implies the use of a computer to make intelligent machines with minimal human intervention. AI is a topic dominating diverse discussions on the future of professional employment, change in the social standard and economic performance. In this paper, I describe fundamental concepts underlying AI and their significance to various fields including aviation and medicine. I highlight issues involved and describe the potential impacts and challenges to the industrial fields. While many benefits are expected in human life with AI integration, problems are needed to be identified and discussed with respect to ethical issues and the future roles of professionals and specialists for their wider application of AI.