• 대한조선학회논문집
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• 제36권1호
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• pp.90-98
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• 1999

감쇠가 적은 금속 구조물의 공진에 의한 진동과 소음을 제어하기 위해 고무, 아스팔트 계열 등의 점탄성 물질이 다양하게 사용되고 있다. 일반적으로 점탄성재료를 이용한 감쇠처리는 점탄성재료의 하부를 모재인 금속층에 취부하고 점탄성재료의 상부를 구속층으로 적층하는 방법을 적용한다. 구속감쇠층이 취부된 구조물의 감쇠 및 강성 특성은 온도와 주파수뿐만 아니라 각 층의 두께에 따라 크게 달라진다. 따라서 구조물을 경량화하고 감쇠처리 효과를 극대화하기 위해서는 점탄성층과 구속층 두께의 최적설계가 매우 중요하다. 본 연구에서는 구속감쇠층을 가진 보의 점탄성층과 구속층의 두께 변화에 따른 손실계수의 변화를 면밀히 검토하고, 이를 토대로 지정된 손실계수를 가지되 감쇠층과 구속층의 최소두께를 결정하는 방법을 제시하였다. 제시된 방법의 타당성은 수치실험적 방법으로 검증하였다.

• 한국인터넷방송통신학회논문지
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• 제17권6호
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• pp.83-88
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• 2017

본 논문에서는 유도무기용 탐색기의 송신 시 고 전력 송수신 신호 분리를 위한 Ka-대역 밀리미터파 3-포트 도파관 순환기를 설계, 제작하였으며 상온에서의 S-parameter 시험, 고 전력 시험, 운용 온도 시험을 통해 성능을 검증하였다. 탐색기 안테나와의 인터페이스 설계 및 소형, 경량화를 위한 표준 도파관 높이의 half-size 설계를 적용하였다. 전기적 성능 구현을 위해 시뮬레이션을 통한 구성 부품인 영구자석, 페라이트 최적 형상 설계 및 포트 별 튜닝 유전체 적용을 통해 성능을 최적화 하였다. 설계된 도파관 순환기는 중심 주파수 Fc 기준 ${\pm}1000MHz$의 대역에서 -20 dB 이하 반사 손실, 0.5 dB 이하 삽입 손실, -23 dB 이하 분리도 특성을 가지며, 측정 결과는 설계 결과와 유사함을 확인하였다.

• Steel and Composite Structures
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• 제27권6호
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• pp.717-725
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• 2018

One of the most important design criteria in military tunnels and armoured doors is to resist the blast loads with minimum structural weight. This can be achieved by using steel sandwich panels. In this paper, the nonlinear behaviour of steel sandwich panels, with different core materials: (1) Hollow (no core material); (2) Rigid Polyurethane Foam (RPF); and (3) Vulcanized Rubber (VR) under free air blast loads, was investigated using detailed 3D nonlinear finite element models in Ansys Autodyn. The accuracy of the finite element model proposed was verified using available experimental test data of a similar steel sandwich panel tested. The results show the developed finite element model can be reliably used to simulate the nonlinear behaviour of the steel sandwich panels under free air blast loads. The verified finite element model was used to examine the different parameters of the steel sandwich panel with different core materials. The result shows that the sandwich panel with RPF core material is more efficient than the VR sandwich panel followed by the Hollow sandwich panels. The average maximum displacement of RPF sandwich panel under different ranges of TNT charge (1 kg to 10 kg at a standoff distance of 1 m) is 49% and 53% less than the VR and Hollow sandwich panels, respectively. Detailed empirical design equations were provided to quantify the maximum deformation of the steel sandwich panels with different core materials and core thickness under a different range of blast loads. The developed equations can be used as a guide for engineer to design steel sandwich panels with RPF and VR core material under a different range of free air blast loads.

• 한국전자통신학회논문지
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• 제13권4호
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• pp.819-826
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• 2018

일반화된 해밍무게는 선형부호의 중요한 파라미터의 하나로써 암호시스템에 적용할 때 부호의 성능을 결정한다. 그리고 격자도를 이용하여 블록부호를 연판정으로 복호할 때 구현에 필요한 상태복잡도를 평가하는 척도가 되기도 함으로써 그 중요성이 한층 부각되고 있다. 특별히 삼항다항식을 기반으로 하는 유한체 상의 비트-병렬 곱셈기에 대한 연구가 진행되어왔다. 셀룰라오토마타(Cellular Automata, 이하 CA)는 국소적 상호작용에 의해 상태가 동시에 업데이트되는 성질이 있어서 LFSR보다 랜덤성이 우수하다. 본 논문에서는 효과적인 암호시스템 설계에 있어 중요한 요소 중 하나인 의사난수열 생성기의 효과적 합성에 관하여 다룬다. 먼저 간단한 90/150 전이규칙 블록의 특성 다항식의 성질을 분석하고, 이 규칙블록을 이용하여 삼항다항식 $x^2^n+x^{2^n-1}+1$($n{\geq}2$)에 대응하는 가역 90/150 CA와 $2^n$차 최대무게다항식에 대응하는 90/150 가역 CA(RCA)의 합성알고리즘을 제안한다.

• 한국산업융합학회 논문집
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• 제17권1호
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• pp.21-26
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• 2014

The focus of this paper is the designing a flexible three fingered hand system with 16 D.O.F for dynamic manipulation with an intelligent controller, and to build a useful database for dynamic manipulation based on the experimental results. The weight of the hand module is only 0.7 kg, but flexible motion and powerful grasping are possible. To achieve such a dynamic motion in a robotic hand, we have developed a flexible fingered hand with a control system incorporating image recognition system in which we deal with the problems of not only accuracy and range of motion but also the flexibility of hand. The fingers are arranged so as to grasp both circular and prismatic objects. In order to achieve the light mechanism, we reduced the number of joints and fingers as much as possible. We used three fingers, which is the minimum number to achieve a stable grasp.

• 대한기계학회논문집A
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• 제26권2호
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• pp.406-414
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• 2002

A new approach, referred to as a successive zooming genetic algorithm (SZGA), is Proposed for identifying a global solution for continuous optimization problems. In order to improve the local fine-tuning capability of GA, we introduced a new method whereby the search space is zoomed around the design point with the best fitness per 100 generation. Furthermore, the reliability of the optimized solution is determined based on the theory of probability. To demonstrate the superiority of the proposed algorithm, a simple genetic algorithm, micro genetic algorithm, and the proposed algorithm were tested as regards for the minimization of a multiminima function as well as simple functions. The results confirmed that the proposed SZGA significantly improved the ability of the algorithm to identify a precise global minimum. As an example of structural optimization, the SZGA was applied to the optimal location of support points for weight minimization in the radial gate of a dam structure. The proposed algorithm identified a more exact optimum value than the standard genetic algorithms.

• 수산해양기술연구
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• 제44권4호
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• pp.362-369
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• 2008

The snow melting system by electric heating wires which is adopted in this research is a part of road facilities to keep surface temperature of the road higher than freezing point of water for melting the snow accumulated on it. The electric heating wires are buried under paved road at a certain depth and operated automatically and manually. Design theory, amount of heating, and installation standard vary according to economic situation, weather condition, installation place and each country applying the system. A main purpose of this study is figuring out the appropriate range of required heat capacity and installation depth and pitch for solving snowdrifts and freezing problems with minimum electric power consumption. This study was performed under the ambient air temperature($-2^{\circ}C$, $-5^{\circ}C$), the pitches of the electric heating wires(200 mm, 300 mm), heating value($250\;W/m^2$, $300\;W/m^2$, $350\;W/m^2$).

• 한국군사과학기술학회지
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• 제1권1호
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• pp.114-127
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• 1998

A user friendly computer code(EMCOMST; Electro-Magnetic response for COMposite STructures) was developed which provides with computations of the response characteristics such as reflectance and transmittance to the incident wave angles, frequencies, composite thicknesses, ply orientations, and types of backplate as the linearly polarized transverse electro-magnetic wave is emitted to the advanced composite structures. In this investigation were reviewed the electromagnetic characteristics of the continuous orthotropic fiber-reinforced organic matrix composites with or without ferrite fillers, which are actively applied to low-weight and high-strength aircraft structures. Also were calculated the response of the three layered compound structures which have appropriately stacked above-mentioned materials as transmitting layer, absorbing layer, reflection layer, respectively under the specific thickness constraints for mechanical strength design requirements. For the composite structures presented in this study, minimum reflectance value less than -5㏈ can be obtained in the frequency range of 4 to 12 ㎓. In addition, analysis of structures attached isotropic radar absorbing materials(RAM) is facilitated by putting the material properties in the material input card entries adequately.

• 복식
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• 제21권
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• pp.5-18
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• 1993

The purpose of this study is to identify the architectural construction of Balenciaga's works. He was perfectionist in tailoring which was based on architectural thought, and couturier who could design, cut, sew and fit a whole gar-ment. Balenciaga has never followed any fashion trend but his own. He designed from within himself, according to his own sensitivity to fashion. Like Chanel, he mad clothes in which women can be comfortable, move in, and get on and off with a minimum of effort. He ap-plied radical shapes to flattering ends, for his clothes echoed movements and gestures, never determined them. He achieved the perfect harmony between the body and the garment, freeing the spirit of the woman within. Reflec-tion his respect for women, Balenciaga never contorted or restriced their bodies. He did not depend on hoops and petticoats to hold out the skirts of his evening dresses but on well-balanced, architectural construction. Therefore in order to identify the architec-tural consturuction, this study hypothesizes (1) the effect of mass and volume, (2) the ef-fect of weight and support, (3) the effect of complexity and simplicity, (4) the effect of line and rhythm etc. The architectural beauty of form in Balenciaga's works are especially based on simplicity and support.

• 한국공작기계학회논문집
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• 제17권6호
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• pp.71-76
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• 2008

The focus of this paper is the designing a flexible three fingered hand system with 16 D.O.F for dynamic manipulation with an intelligent controller, and to build a useful database for dynamic manipulation based on the experimental results. The weight of the hand module is only 0.7 kg, but flexible motion and powerful grasping are possible. To achieve such a dynamic motion in a robotic hand, we have developed a flexible fingered hand with a control system incorporating image recognition system in which we deal with the problems of not only accuracy and range of motion but also the flexibility of hand. The fingers are arranged so as to grasp both circular and prismatic objects. In order to achieve the light mechanism, we reduced the number of joints and fingers as much as possible. We used three fingers, which is the minimum number to achieve a stable grasp.