• 대한수학교육학회지:수학교육학연구
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• 제20권2호
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• pp.185-202
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• 2010

본 연구는 중등수학교육에서 도구화된 CAS에 기반한 최적화 문제해결 활동을 통해 CAS가 교육과정 내용제시 순서에 영향을 줄 수 있는지를 분석하기 위해 설계되었다. 이를 위하여 본 연구자는 CAS를 활용한 최적화 문제해결 활동을 구안하였으며 3개월간의 CAS 활용 수업 경험이 있으나 아직 미적분학을 접해 본 적이 없는 고등학교 2학년 7명을 선정하여 총 9차시의 수업을 실시하고, 수업녹화자료와 면담을 통해 학생들의 활동을 분석하였다. 분석 결과, 학생들은 CAS를 이용하여 미 학습된 교육내용인 미분과 삼차방정식, 무리방정식의 해구하기와 그래프 분석이 포함된 최적화 문제해결활동을 수준 높게 다룰 수 있는 것으로 나타나 CAS가 교육과정 내용제시 순서에 영향을 줄 수 있음을 확인할 수 있었다.

• Journal of applied mathematics & informatics
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• 제40권1_2호
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• pp.289-303
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• 2022

This article examines the multidimensional index extraction method of the disability social security system based on data mining. While creating the data warehouse of the social security system for the disabled, we need to know the elements of the social security indicators for the disabled. In this context, a clustering algorithm was used to extract the indicators of the social security system for the disabled by investigating the historical dimension of social security for the disabled. The simulation results show that the index extraction method has high coverage, sensitivity and reliability. In this paper, a multidimensional extraction method is introduced to extract the indicators of the social security system for the disabled based on data mining. The simulation experiments show that the method presented in this paper is more reliable, and the indicators of social security system for the disabled extracted are more effective in practical application.

• 대한수학교육학회지:학교수학
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• 제11권3호
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• pp.527-546
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• 2009

본 연구는 CAS가 도입된 이후의 우리나라 수학교육에 대비하여 고등학교 수학활동에서 CAS의 도구발생 과정을 통찰하고, 중등수학교육에서 도구화된 CAS의 활용 가능성을 탐색하기 위해 설계되었다. 이를 위하여 본 연구자는 CAS에 기반 한 개념중심 수학과제 학습과 문제해결을 각각 고안하였으며 고등학교 1학년생 7명을 대상으로 총 12차시의 수업을 실시하고 수업녹화자료와 면담을 통해 학생들의 활동을 분석하였다. 분석결과 학생들은 CAS를 이용하여 수준 높은 응용문제를 다룰 수 있는 것으로 나타나 CAS가 교육과정 내용수준에 영향을 줄 수 있음을 확인할 수 있었고, 또 도구화된 CAS에 기반 한 무리방정식 문제해결활동을 통해 CAS가 교육과정의 제시 순서에 영향을 줄 수 있음을 발견하였다. 이 연구는 고등학교 수학교육에서 CAS의 도구발생을 분석하여 사례를 제공함으로써 CAS가 도입된 이후의 우리나라 수학교육에 대비한 기초연구가 될 것이다.

• 전기전자학회논문지
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• 제27권3호
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• pp.213-219
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• 2023

경찰청 통계자료에 따르면 코로나19 이후 문자 또는 메신저를 이용한 스미싱(Smishing) 범죄가 급증하였다. 또한 정부 기관에 접수된 공공기관 사칭 건수의 대부분이 백신접종 및 보상 관련하여 가짜 URL(Uniform Resource Locator)을 클릭하도록 유도하는 수법이 다수 사용되었다. 주로 URL의 정보를 숨긴 단축 URL을 사용하며 탐지할 때 URL 기반 탐지방법은 URL의 정보를 숨기면 제대로 탐지할 수 없고, 콘텐츠 기반 탐지 방법은 탐지 속도가 느리고 많은 자원을 사용한다. 이에 본 논문에서는 GRU(Gated Recurrent Units)를 이용한 단축 URL을 판별하는 과정을 통해 일반 URL일 때 transformer를 통한 URL 기반 탐지, 단축 URL일때 XGBoost를 이용한 콘텐츠 기반 탐지하는 시스템을 제안한다. 제안한 탐지 시스템의 F1-Score는 94.86이었고, 처리시간은 평균 5.4초가 소요되었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.830-833
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• 2002

To solve the internal security problem such as human error and bad faith, the automation of computer system management is significant. For this purpose, we focus attention in the automation of Mail Delivery Service. Today, requirement for reliable mail delivery system becomes larger and larger. However, existing systems are too strict about their configuration. Hence, we propose the method based on Reinforcement Learning (RL) to achieve proper MX record ordering. A measure on validity of the design of system, such as network topology number of servers and so on, is also obtained as side benefit. In order to verify the usability of the presented method, we did on a small model of mail delivery system. As a result, we show that RL is available for determination of the proper MX record ordering. Additionally, we suggest that it is also available for comparing validity of setting of MTA and the network design.

• Journal of applied mathematics & informatics
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• 제6권1호
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• pp.175-184
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• 1999

Along with the computation and analysis for nonlinear system being more and more involved in the fields such as automation control electronic technique and electrical power system the nonlin-ear theory has become quite a attractive field for academic research. In this paper we derives the solutions for state equation of nonlinear system by using the inverse operator expression of the so-lutions is obtained. An actual computation example is given giving a comparison between IOM and Runge-kutta method. It has been proved by our investigation that IOM has some distinct advantages over usual approximation methods in that it is computationally con-venient rapidly convergent provides accurate solutions not requiring perturbation linearization or the massive computation inherent in discrietization methods such as finite differences. So the IOM pro-vides an effective method for the solution of nonlinear system is of potential application valuable in nonlinear computation.

• Current Optics and Photonics
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• 제2권6호
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• pp.540-546
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• 2018

We propose an implementation scheme for an optical encryption system with hybrid-pattern random keys. In the encryption process, a pair of random phase keys composed of a white-noise phase key and a structured phase key are positioned in the input plane and Fourier-spectrum plane respectively. The output image is recoverable by digital reconstruction, using the conjugate of the encryption key in the Fourier-spectrum plane. We discuss the system encryption performance when different combinations of phase-key pairs are used. To measure the effectiveness of the proposed method, we calculate the statistical indicators between original and encrypted images. The results are compared to those generated from a classical double random phase encoding. Computer simulations are presented to show the validity of the method.

• 대한수학회보
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• 제57권1호
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• pp.251-274
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• 2020

We study a dynamical system that was originally defined by Romik in 2008 using an old theorem of Berggren concerning Pythagorean triples. Romik's system is closely related to the Farey map on the unit interval which generates an additive continued fraction algorithm. We explore some number theoretical properties of the Romik system. In particular, we prove an analogue of Lagrange's theorem in the case of the Romik system on the unit quarter circle, which states that a point possesses an eventually periodic digit expansion if and only if the point is defined over a real quadratic extension field of rationals.

• Journal of applied mathematics & informatics
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• 제17권1_2_3호
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• pp.737-746
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• 2005

Average memory occupancy and congestion in computer system or communication system may be reduced further if new jobs are admitted only when the number of jobs queued at CPU is below a certain threshold, run queue cutoff (RQ). In our previous paper we showed that response time of a job is invariant with respect to RQ if jobs do not communicate each other. In this paper, we prove that the invariance property by considering the evolution of the queue lengths as point processes. We also present an approximate method for the delay due to context switching under time slicing.

• Journal of applied mathematics & informatics
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• 제16권1_2호
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• pp.539-550
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• 2004

We consider communication or computer systems that have the average memory occupancy and congestion. A certain system may be reduced further if new processes are admitted only when the number of processes queued at the processor is below a certain threshold, run queue cutoff(RQ). We show that response time of a process is invariant with respect to RQ when processes do not communicate each other. The invariance property is considered with the evolution of the queue lengths as point processes and demonstrate it numerically using matrix-geometric methods. We illustrate the RQ invariance property.