• Nuclear Engineering and Technology
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• 제28권5호
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• pp.431-439
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• 1996

In the process of simplifying the complex fate of the plant into a binary state, the information loss is inevitable. To minimize the information loss, the quantification of plant safety status has been formulated through the combination of the probability density function arising from the sensor measurement and the membership function representing the expectation of the state of the system. Therefore, in this context, the safety index is introduced in an attempt to quantify the plant status from the perspective of safety. The combination of probability density function and membership function is achieved through the integration of the fuzzy intersection of the two functions, and it often is not a simple task to integrate the fuzzy intersection due to the complexity that is the result of the fuzzy intersection. Therefore, a methodology based on the Algebra of Logic is used to express the fuzzy intersection and the fuzzy union of the arbitrary functions analytically. These exact analytical expressions are then numerically integrated by the application of Monte Carlo method. The benchmark tests for rectangular area and both fuzzy intersection and union of two normal distribution functions have been performed. Lastly, the safety index was determined for the Core Reactivity Control of Yonggwang 3&4 using the presented methodology.

• 대한수학회논문집
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• 제32권1호
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• pp.7-17
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• 2017

Let R be a commutative ring with zero-divisors Z(R). The extended zero-divisor graph of R, denoted by $\bar{\Gamma}(R)$, is the (simple) graph with vertices $Z(R)^*=Z(R){\backslash}\{0\}$, the set of nonzero zero-divisors of R, where two distinct nonzero zero-divisors x and y are adjacent whenever there exist two non-negative integers n and m such that $x^ny^m=0$ with $x^n{\neq}0$ and $y^m{\neq}0$. In this paper, we consider the extended zero-divisor graphs of idealizations $R{\ltimes}M$ (where M is an R-module). At first, we distinguish when $\bar{\Gamma}(R{\ltimes}M)$ and the classical zero-divisor graph ${\Gamma}(R{\ltimes}M)$ coincide. Various examples in this context are given. Among other things, the diameter and the girth of $\bar{\Gamma}(R{\ltimes}M)$ are also studied.

• 전기학회논문지P
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• 제58권3호
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• pp.316-322
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• 2009

This paper presents an analytical design method of a passive harmonic filter for a three-phase diode rectifier and uses a new transfer function approach in the analysis and design. The transfer function approach derives an analytical formulation of an utility system including passive filters with a basis of Laplace transform and provides a graphical formulation so that a visualized insight into an interaction between individual filter and system response can be attainted. Harmonic impedance, voltage division and current division transfer function are used as a design tool, which makes a calculated filter parameters to satisfy IEEE-519 distortion limits. A simple five-step design procedure is introduced in the filter design, which consists of system analysis, selection of PCC(Point of Common Coupling), filter specification calculation, appropriate filter design for system and filter implementation. Philosophy governing the design procedure is based on a numerical/graphical iterative solution, trial and error with visualization feed-back based on "algebra on the graph". Finally, performance of the designed passive harmonic filter is verified by experiment and shows that 5th, 7th, 9th, 11th and 13th harmonics are decreased within IEEE-519 distortion limits, respectively.

• 한국통신학회논문지
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• 제28권7A호
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• pp.557-562
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• 2003

An output multiplexer of manifold type is widely used in a recent satellite transponder for its mass and volume reduction. For correct operation, the filters of such a multiplexer must be singly terminated. In this paper, a simple synthesis method of a 6-pole dual-mode singly-terminated filter is described. From the transfer function of the filter, network parameters such as in/output terminations and coupling coefficients are obtained easily without complicated matrix algebra such as orthogonal projection and similarity transformation. Two different-structure filters are taken into consideration and the network parameters of each filter have been extracted from the same transfer function. It is shown that the responses of two filters are same to each other since their network parameters are obtained from the same transfer function. The method described in this paper can be applied to the other degree singly terminated filter.

• 한국전자파학회논문지
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• 제15권1호
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• pp.51-59
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• 2004

본 논문에서는 LDPC에 근거한 semi-BICM 기법에 의해 다중 레벨 부호화(MLC)를 설계한다. 기존의 설계와는 다르게 그레이 매핑에 의해 MLC와 BICM을 결합함으로써 서로 다른 부호율(code rate)의 다수의 등가 채널상에서의 멀티미디어 데이터 전송이 가능하다. AWCN 채널용량에 매우 가까운 SNR에서 양호한 성능을 얻기 위해 랜덤 레귤러 LDPC 부호와 단순한 SA-LDPC 부호를 병렬 독립 복호가 가능한 MLC 부호로서 고찰하였다. 또한, 제안방식은 멀티미디어 통신시스템을 위한 전력 및 대역폭 효율을 얻을 수 있음을 수치해석 결과를 이용하여 나타내었다.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 1999년도 추계종합학술대회
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• pp.248-251
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• 1999

We extend the sue of the method of least square to develop a recursive algorithm for the design of adaptive transversal filters such that, given the least-square estimate of this vector of the filter at iteration n-1, we may compute the updated estimate of this vector at i(oration n upon the arrival of new data. The RLS algorithm may be viewed as a special case of the Kalman filter. Indeed this special relationship between the RLS algorithm and the Kalman filter is considered. We begin the development of the RLS algorithm by reviewing some basic relations that pertain to the method of least squares. Then, by exploiting a relation in matrix algebra known as the matrix inversion lemma, we develop the RLS algorithm. An important feature of the RLS algorithm is that it utilizes information contained in the input data, extending back to the instant of time when the algorithm is initiated. The resulting rate of convergence is therefore typically an order of magnitude faster than the simple LMS algorithm. This improvement in performance, however, Is achieved at the expensive of a large increase in computational complexity.

• 한국통신학회논문지
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• 제25권5B호
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• pp.830-841
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• 2000

We extend the sue of the method of least square to develop a recursive algorithm for the design of adaptive transversal filters such that, given the least-square estimate of this vector of the filter at iteration n-1, we may compute the updated estimate of this vector at iteration a upon the arrival of new data. We begin the development of the RLS algorithm by reviewing some basic relations that pertain to the method of least squares. Then, by exploiting a relation in matrix algebra known as the matrix inversion lemma, we develop the RLS algorithm. An important feature of the RLS algorithm is that it utilizes information contained in the input data, extending back to the instant of time when the algorithm is initiated. In this paper, we propose new tap weight updated RLS algorithm in adaptive transversal filter with data-recycling buffer structure. We prove that convergence speed of learning curve of RLS algorithm with data-recycling buffer is faster than it of exiting RL algorithm to mean square error versus iteration number. Also the resulting rate of convergence is typically an order of magnitude faster than the simple LMS algorithm. We show that the number of desired sample is portion to increase to converge the specified value from the three dimension simulation result of mean square error according to the degree of channel amplitude distortion and data-recycle buffer number. This improvement of convergence character in performance, is achieved at the (B+1)times of convergence speed of mean square error increase in data recycle buffer number with new proposed RLS algorithm.

• 한국항행학회논문지
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• 제15권2호
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• pp.181-188
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• 2011

소형무인항공기의 경우 유효탑재하중의 여유가 많지 않기 때문에 AHRS의 소형화가 필요하다. 본 논문에서는 소형무인항공기를 위해 소형, 경량으로 설계 제작한 AHRS의 성능을 가속도 외란이 적은 환경에서 시험하고 평가하였다. 센서는 저가의 MEMS 제품을 사용했으며 자세 보정을 위해 가속도계와 지자기계가 같이 사용되었다. 자세계산에는 특이점이 존재하지 않고 비교적 계산이 간단한 쿼터니언을 사용했으며 자세 보정 알고리듬에는 칼만필터가 사용되었다. 본 논문에서는 소형무인항공기에 성공적으로 적용된 사례가 있는 상용 항법장치와의 비교를 통해 설계된 AHRS의 성능시험을 진행하였다. 설계된 AHRS의 자세 데이터가 상용 항법장치와 수직축 $0.5^{\circ}$이내, 수평축 $1.5^{\circ}$ 이내로 허용 가능한 차이를 가지는 것을 보였으며, 본 시험환경 내에서 소형무인항공기제어에 적합한 자세각 출력을 내는 것을 확인하였다.

• 한국수학사학회지
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• 제17권4호
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• pp.101-122
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• 2004

수학 교육에서 수학을 어떻게 가르칠 것인가는 근본적인 문제의 하나이다. 이에 대해 본 논문에서는 수학사를 활용한 수학 교육을 주장한다. 그것은 수학 교육을 위해 수학의 이해가 필요하며, 또한 수학의 이해에는 수학사를 활용하는 것이 효과적이기 때문이다. 특히 여기서는 기하학에 초점을 두었다. 우리는 기하학의 기원에서 20세기 중반의 미분 기하학에 이르기까지 등장하는 중요한 기하학을 세 가지 기준, 즉 내ㆍ외적 배경, 특징(연구 방법, 대상), 현대 수학에의 영향에 따라 비교 연구하였다. 그 수학교육에의 응용으로 역사적 자료를 바탕으로 수학지도의 순서를 결정하는 문제에 대해 고려하였다.

• 대한수학교육학회지:수학교육학연구
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• 제23권3호
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• pp.389-406
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• 2013

본 연구는 수학과 서술형 평가에서 나타난 중학교 2학년 학생들의 오류 유형을 문항별, 학습 수준별로 분석함으로써 효과적인 교수 학습 과정을 촉진하기 위한 기초자료를 제공하는 것을 목적으로 한다. 총 99명의 중학교 2학년 학생들의 문항 반응을 분석한 결과, 수학적 사고와 표현, 현실 맥락과 연결된 문항 혹은 수학 내용들이 연결된 문항 등에서 다양한 오류가 나타났으며 단일 오류뿐만 아니라 복합적인 오류 유형도 발견되었다. 학습 수준에 따라서도 상위 수준의 학생들은 복합적 오류 보다는 단일 오류가, 중하위 수준의 학생들은 복합적인 오류가 더 빈번히 나타났으며 오류 유형도 다양하였다. 이러한 결과는 문항의 유형별, 학습 수준별 학생들의 오류 패턴을 보여주는 것으로 향후 학생들의 오류를 수정하고 수학 학습을 촉진할 수 있는 서술형 평가 문항과 교수법 개발에 도움이 될 수 있을 것이다.