• Communications of Mathematical Education
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• v.23 no.3
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• pp.583-597
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• 2009

The purposes of this study are to analyze error that the students in science and engineering show in the process of thinking a extremum value. First, in view of examples of incorrect answers that appeared in a test by students in science and engineering, it has been found that the most frequent incorrect answers were due to a lack of understanding about necessary matters and concepts. In this regard, it is necessary to use various examples and pictures(graphs) to teach students in science and engineering. In addition, it has been found that it is more effective to use questions asking why it happens and why they think that way to help those having difficulties in understanding various concepts and principles.

• Journal of Navigation and Port Research
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• v.43 no.1
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• pp.1-8
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• 2019

Identifying behavioral errors of seafarers that have led to marine accidents is a basis for research into prevention or mitigation of marine accidents. The purpose of this study is to estimate the optimal probability distribution function needed to model behavioral errors of crew members into three behaviors (i.e., Skill-, Rule-, Knowledge-based). Through use of behavioral data obtained from previous accidents, we estimated the optimal probability distribution function for the three behavioral errors and verified the significance between the probability values derived from the probability distribution function. Maximum Likelihood Estimation (MLE) was applied to the probability distribution function estimation and variance analysis (ANOVA) used for the significance test. The obtained experimental results show that the probability distribution function with the smallest error can be estimated for each of the three behavioral errors for eight types of marine accidents. The statistical significance of the three behavioral errors for eight types of marine accidents calculated using the probability distribution function was observed. In addition, behavioral errors were also found to significantly affect marine accidents. The results of this study can be applied to predicting marine accidents caused by behavioral errors.

• Journal of the Korean School Mathematics Society
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• v.16 no.2
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• pp.435-457
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• 2013

The purpose of this paper is to discover effective teaching and learning methods for improving low level mathematic matriculants', who passed the early decision program, problem solving abilities by analyzing their error patterns in the special lecture for basic mathematics in P University. In this paper, we examine the matriculants' understanding and errors on the fundamental concepts of function, and continuity and differentiability of function based on the pre-examination. We also measure the their academic achievement in the special lecture for basic mathematics, and analyze the differences of error patterns between pre-test and post-test result on the concepts of continuity and differentiability of function.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.8
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• pp.797-803
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• 2002

In this paper we derive the probability density function of the phase error of the received signal over Rician fading channel and verify its propriety as the probability density function using the zeroth moment. In general, for the error probability over fading channel we compute the error probability in the first place when it is only AWGN, and then we get the final result by averaging the first result and the probability density function of the corresponding fading channel. In this paper, however, we compute the error probability by double integration after the probability density function over fading channel is computed.

• Communications of Mathematical Education
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• v.24 no.3
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• pp.709-730
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• 2010

The inverse function of a one-to-one correspondence is explained with a graph, a numerical formula or other useful expressions. The purpose of this paper is to know how low achieving students understand the learning contents needed reversible thinking about irrational functions. Low achieving students in this study took paper-pencil test and their written answers were collected. They made various mistakes in solving problems. Their error types were grouped into several classes and identified in this analysis. Most students did not connected concepts that they learned in the lower achieving students to think in reverse order in case of and to visualize concepts of functions. This paper implies that it is very important to take into account students' accommodation and reversible thinking activity.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.4C
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• pp.401-407
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• 2010

In this paper, we consider a low-complex companding technique for peak-to-average power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. For the technique, we propose a novel companding function to compensate the problem of the conventional companding functions which are difficult to design complying with system requirements and deteriorate the bit error rate (BER) performance significantly. The proposed scalable companding function can provide an arbitrary value of the maximum PAPR with which the BER performance changes gracefully. In addition, the proposed companding function can be designed readily according to the PAPR and BER performance required by the system and is observed to provide better BER performance than the conventional clipping and $\mu$-low companding schemes under the similar PAPR condition.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.938-941
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• 2010

Though a compiler checks memory errors, it is difficult for the compiler to detect function pointer errors in code level. Thus, in this paper, we propose a method for effectively detecting Invalid function pointer access errors, by analyzing assembly codes that are obtained by disassembling an executable file. To detect the errors, assembly codes in disassembled files are checked out based on the instruction transition diagrams which are constructed through analyzing normal usage patterns of function pointer access. When applying the proposed method to various programs having no compilation error, a total of about 500 potential errors including the ones of well-known open source programs such as Apache web server and PHP script interpreter are detected among 1 million lines of assembly codes corresponding to a total of about 10 thousand functions.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2015.07a
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• pp.239-241
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• 2015

인적오류는 해양사고의 주요한 원인을 차지하고 있으나 그동안 이에 대한 연구가 미흡한 실정이다. 본 연구에서는 해양사고의 인적요소 중 혼잡해역이나 협수로 등에서 타 선박에 대한 다양한 조우 상황별 항해사가 받는 스트레스 값을 실험하였다. 또한 GEV distribution을 적용하여 인적오류 평가모델을 개발하고자 하였고 선박 실험을 통하여 도출된 데이터를 통하여 분포함수와 스트레스 수치 사이의 오차를 계산하고 평가하였다. 향후 본 모델의 개발을 통하여 선박 운항자의 스트레스 정도를 예측 할 수 있고 이에 따른 사고 예방 조치 및 적절한 교육훈련 실시 등 다양한 인적 오류 저감을 위한 대책마련에 도움이 되고자 하는 목적이다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2019.01a
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• pp.9-10
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• 2019

항공기 소프트웨어는 기능적 실패 시 인명피해나 재산피해와 같은 큰 사고로 이어질 수 있다. 따라서 항공기 소프트웨어 개발과정에서 엄격한 검증 프로세스를 수행하지만 오류를 완벽히 제거하는 것은 어렵다. 병행 프로그램에서 발생하는 동시성 오류는 잘못된 동기화에 의하여 공유자원을 사용할 때 발생할 수 있다. 하지만 복잡한 인터리빙을 모두 고려하여 디버깅하기 어렵기 때문에 자율적으로 수리되어야 한다. 본 논문은 항공기 소프트웨어에서 함수 호출을 기반으로 동시성 오류를 자율적으로 수리하는 기법을 제시한다. 제시하는 기법은 모니터 및 컨트롤 엔진, 순차정보 제공 엔진, 건전성 관리시스템으로 구성된다.

• Review of KIISC
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• v.16 no.4
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• pp.47-58
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• 2006

전통적인 암호시스템의 분석방법은 암호 프리미티브들로 구성된 부분을 블랙박스로 생각하고 이들을 구성하는 수학적 함수를 분석하여 이론적인 안전성을 정량화 했다. 그러나 암호 프리미티브가 이론적으로 안전하다고 해도 이들을 적용한 암호시스템을 구축할 때 구현 방법에 따라 비밀정보와 연관된 내부 함수가 실행되면서 연산시간, 소모전력, 전자복사, 오류결과 등의 부가적인 정보를 밖으로 누출하는 경우가 있다. 최근 들어 이런 부채널 정보를 통해 비밀정보를 유추하는 기술이 발전하였는데 시차공격법, 전력분석법, 전자복사 공격법, 오류 공격법, 오류 메시지 공격법 등 여러 가지 공격법이 알려지고 있다. 부채널 공격법을 통해 비밀키 암호 알고리즘, 공개키 암호 알고리즘, 해쉬함수 등을 프리미티브로 사용하여 구현한 암호 메카니즘의 취약점이 분석되었으며, 이를 막을 수 있는 대응법도 다양하게 제안되고 있다. 본 고에서는 부채널 공격법과 이의 대응법에 대한 최근 동향을 살펴본다.