• 한국건축시공학회지
• /
• 제2권4호
• /
• pp.177-182
• /
• 2002

The purpose of this study is to develope the strength prediction model by Maturity Method. A maturity function is a mathematical expression to account for the combined effects of time and temperature on the strength development of a cementious mixture. The method of equivalent ages is to use Arrhenius equation which indicates the influence of curing temperature on the initial hydration ratio of cement. For the experimental factors of this study, we selected the concrete mixing of W/C ratio 45, 50, 55 and 60% and curing temperature 5, 10, 20 and $30^{\circ}C$. And we compare and evaluate with logistic model that is existing strength prediction model, because we have to verify adaption possibility of new strength prediction model which is proposed by maturity method. As the results, it is found that investigation of the activation energy that are used to calculate equivalent age is necessary, and new strength prediction model was proved to be more accurate in the strength prediction than logistic model in the early age. Moreover, the use of new model was more reasonable because it has low SSE and high decisive factor.

• 한국통신학회논문지
• /
• 제39C권11호
• /
• pp.1124-1131
• /
• 2014

처프 확산 대역 (chirp spread spectrum: CSS) 기술은 데이터 신호를 처프 신호를 통하여 전송하는 기술로, 잠수함 음향 탐지 등 해양 무선 통신 분야에서 널리 이용되어 왔다. 하지만, 해양 통신 중 존재하는 다중 경로 환경으로 인하여, CSS 기술의 데이터 전송률이 낮아질 수 있다. 이를 극복하기 위하여, 데이터 전송률을 증가시킬 수 있는 오버랩 기반 처프 확산 대역 기술을 제안하고 분석한다. 근사화된 가우시안 Q 함수를 바탕으로 오버랩 기반 CSS 시스템의 닫힌꼴 비트 오류율 (bit error rate: BER) 수식을 유도하고, 또한 오버랩 횟수에 따른 심벌 간 간섭을 (intersymbol interference: ISI) 분석한다.

• 조명전기설비학회논문지
• /
• 제26권10호
• /
• pp.89-94
• /
• 2012

This research is to apply the control of neuron networks for the real-time walking control of Multi-articulated robot. Multi-articulated robot is expressed with a complicated mathematical model on account of the mechanic, electric non-linearity which each articulation of mechanism has, and includes an unstable factor in time of walking control. If such a complex expression is included in control operation, it leads to the disadvantage that operation time is lengthened. Thus, if the rapid change of the load or the disturbance is given, it is difficult to fulfill the control of desired performance. This paper proposes a new mode to implement a neural network controller by installing a real object for controlling and an algorithm for this, which can replace the existing method of implementing a neural network controller by utilizing activation function at the output node. The proposed control algorithm generated control signs corresponding to the non-linearity of Multi-articulated robot, which could generate desired motion in real time.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2013년도 춘계학술대회
• /
• pp.17-20
• /
• 2013

본 연구는 외란하에서 선박 트랙 키핑에 대한 수치시뮬레이션 문제를 다루었다. 이용된 선박 모델은 새누리호 선박을 이용하여, 목포항 입구부터, 목표 부두까지 항로에서의 항로 추종를 자동제어 기법을 이용하여 시뮬레이션 수행하였다. 기존 과거 연구의 선박 트랙 키핑 문제는 주로 정속에서 수행되었으나, 본 연구에서 부두에 접안하기 전 단계까지를 감안하여, 선박 속도를 저하시키며, 접안 하기 직전 선박이 목표 지점에 도달하여 정지할 때까지의 트랙 키핑 문제를 다루었다. 사용 제어 기법은 PID기법, 외란으로 바람 영향을 고려한 트랙키핑 시뮬레이션을 수행하였고, 그 결과 접안 직전 지점까지 적정하게 속도를 저하시키며, 원하는 항로를 따라 자동 제어 됨을 알 수 있었다.

• Journal of information and communication convergence engineering
• /
• 제9권4호
• /
• pp.435-440
• /
• 2011

This paper propose the method of constructing the highly efficiency adder and multiplier systems over finite fields. The addition arithmetic operation over finite field is simple comparatively because that addition arithmetic operation is analyzed by each digit modP summation independently. But in case of multiplication arithmetic operation, we generate maximum k=2m-2 degree of ${\alpha}^k$ terms, therefore we decrease k into m-1 degree using irreducible primitive polynomial. We propose two method of control signal generation for the purpose of performing above decrease process. One method is the combinational logic expression and the other method is universal signal generation. The proposed method of constructing the highly adder/multiplier systems is as following. First of all, we obtain algorithms for addition and multiplication arithmetic operation based on the mathematical properties over finite fields, next we construct basic cell of A-cell and M-cell using T-gate and modP cyclic gate. Finally we construct adder module and multiplier module over finite fields after synthesizing ${\alpha}^k$ generation module and control signal CSt generation module with A-cell and M-cell. Next, we constructing the arithmetic operation unit over finite fields. Then, we propose the future research and prospects.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2018년도 추계학술발표대회
• /
• pp.885-888
• /
• 2018

This paper researches a way of detecting fish robots moving in an aquarium. The fish robot was designed and developed for interactions with humans in aquariums. It was studied merely to detect a moving object in an aquarium because we need to find the positions of moving fish robots. The intention is to recognize the location of robotic fish using an image processing technique and a video camera. This method is used to obtain the velocity for each pixel in an image, and assumes a constant velocity in each video frame to obtain positions of fish robots by comparing sequential video frames. By using this positional data, we compute the distance between fish robots using a mathematical expression, and determine which fish robot is leading and which one is lagging. Then, the lead robot will wait for the lagging robot until it reaches the lead robot. The process runs continuously. This system is exhibited in the Busan Science Museum, satisfying a performance test of this algorithm.

• 전력전자학회논문지
• /
• 제16권1호
• /
• pp.71-78
• /
• 2011

본 논문에서는 영구자석 동기 전동기의 센서리스 운전에 있어, 제어에 사용되는 제정수의 오차가 각도 추정 성능에 미치는 영향을 분석하였다. 회전 자속의 위치를 추정하는데 사용되는 위치 오차 정보를 부호 요인과 이득 요인으로 나누어, 그 중에 각도 추정의 편차를 초래하는 부호 요인을 중심으로 제정수 오차가 각도 추정 성능에 미치는 영향을 분석하였다. 본 논문에서는 센서리스 제어에 사용되는 저항과 인덕턴스의 오차로 표현되는 각도 추정 편차의 함수를 수식적으로 도출하였고, 모의실험 및 실험을 통해 도출된 수식의 타당성을 검증하였다.

• Journal of Power Electronics
• /
• 제18권1호
• /
• pp.116-128
• /
• 2018

Conventionally, in order to reduce the ac components of the dc-link capacitors of the two-level Half-Bridge Voltage Source Inverter (HB-VSI), high dc-link capacitances are required. This necessitates the employment of short-lifetime and bulky electrolytic capacitors. In this paper, an analysis for the performance of low dc-link capacitances-based HB-VSI is presented to elucidate its ability to generate an enhanced fundamental output voltage magnitude without increasing the voltage rating of the involved switches. This feature is constrained by the load displacement factor. The introduced enhancement is due to the ac components of the capacitors' voltages. The presented approach can be employed for multi-phase systems through using multi single-phase HB-VSI(s). Mathematical analysis of the proposed approach is presented in this paper. To ensure a successful operation of the proposed approach, a closed loop current controller is examined. An expression for the critical dc-link capacitance, which is the lowest dc-link capacitance that can be employed for unipolar capacitors' voltages, is derived. Finally, simulation and experimental results are presented to validate the proposed claims.

• 한국수학사학회지
• /
• 제21권1호
• /
• pp.29-44
• /
• 2008

퍼지 논리는 1965년 Zadeh([13])에 의하여 소개된 이후 꾸준히 확장, 발전하였다. 퍼지 논리와 관련된 수학사 및 수학교육 논문([1], [2], [3], [4], [5], [7])들이 많이 발표되었지만 정작 퍼지 논리의 창시자인 Zadeh에 대한 연구 논문은 아직 발표되지 않았다. 본 논문에서는 Zadeh의 생애와 업적을 알아보고 이를 통해 우리가 배워야 할 점들에 대해 논의한다. 또한 이가 논리, 다가 논리, 퍼지 논리, 직관주의 논리 및 직관적 퍼지 집합을 비교, 분석하고 직관적 퍼지 집합에서 '직관적(intuitionistic)' 이라는 용어의 부적절성에 대해 논의한다.

• 한국멀티미디어학회논문지
• /
• 제19권8호
• /
• pp.1337-1344
• /
• 2016

As the visual effect frequently used in movies or animations, special effects are well suited for the creation of buildings or materials' destruction and collapse scenes. With the relevant programs developing technologically, the adoption of a real-time physically based-system makes it possible to realistically express dynamic simulations. In the large scale, the visual expression of such effects of destroying is satisfying enough, but most common programs of those effects fail to maximize visual effect generated with the cutting of small materials. Besides, to perform a heavy simulation process needs high-performance hardware and programs, where high costs would become a serious issue. For this reason, this paper suggests a solution optimized for the effect of small materials-cutting. The progress of each step shows technologies which trace movement with the state of the completion of the character's motions and then cut the material in real-time, finally led to the very realistic visual effect. Besides, using vector inner calculation to follow the motions of object and to realize cutting effect, this study provides an experiment that constructs visual effect for visualization from the basis of mathematical algorithm and it would be certainly as an educational material used for further researches.