• 한국자동차공학회논문집
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• 제7권6호
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• pp.144-155
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• 1999

An occupant analysis code SAFE (Safety Analysis For occupant crash Environment) is utilized to simulate and improve the crash performance of an energy absorbing steering system. The safety standard FMVSS 203 is simulated and used for design evaluations . Segments and contact elliposids are utilized to model the bod blocks and the components of the steering system with SAFE. Spring-damper elements and force-deflection characteristics are utilized to model the energy absorbing components such as the plate and the polyacetal molding. The plate absorbs the impact energy through tensile deformation . Whereas, the polyacetal molding absorbs the impact energy through compression. the body block test is carried out to validate tie simulation model, and real component tests are performed to extract the force-deflection curves . After the model is validated , the parameter study is carried out to evaluate the crash performance of the energy absorbing components. A performance measure is defined for the parameter study. Using the results of the parameter study and managing the orthogonal arrays, optimum design values of energy absorbing components are determined to minize the occupant injury.

• Ocean and Polar Research
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• 제26권2호
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• pp.333-339
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• 2004

This paper is concerned with an experimental investigation about tractive performance of a tracked vehicle on extremely soft soil. A tracked vehicle model with principal dimensions of $0.9\;m(L)\;{\times}\;0.75\;m(B)\;{\times}\;0.4\;m(H)$ and the weight of 167 kg was constructed with a pair of driving chain links driven by two AC-servo motors. The tracks are configured with detachable grousers with variable span. Deep seabed was simulated by means of bentonite-water mixture in a soil bin of $6.0\;m(L)\;{\times}\;3.7\;m(B)\;{\times}\;0.7\;m(H)$. Slip of vehicle and driving torque of motor were measured with respect to experimental variables; grouser span, grouser chevron angle, driving speed, drawbar-pull weight, position of center-of-gravity and weight. $L_8$ orthogonal array is adopted for DOE (Design Of Experiment). The effects of experiment variables on traction performance are evaluated.

• 한국통신학회논문지
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• 제34권11A호
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• pp.815-821
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• 2009

본 논문에서는 두 명의 상호협력 사용자가 추가적인 대역을 사용하지 않고도 서로의 데이터를 공간적으로 다중화 할 수 있는, 공간적으로 좌표 재배열된 직교 설계 기반의 새로운 상호협력 통신 기법을 제안한다. 제안하는 기법은 기존의 상호협력 통신기법에 비해 다이버시티 이득 (다이버시티 이득 2) 뿐만 아니라 추가적인 코딩 이득을 얻을 수 있음을 보인다. 상호협력 통신에 참여하는 특정 사용자 노드가 자신과 짝을 이루어 동일한 목적지 노드(즉, 셀룰러 네트워크에서의 기지국)와 통신할 수 있는 또 다른 사용자 노드를 찾을 수만 있다면, 제안하는 기법을 통해 셀룰러 네트워크에서 상향링크의 비트 오류율 성능을 향상시킬 수 있음을 시뮬레이션 결과를 통해 확인한다.

• Current Optics and Photonics
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• 제5권6호
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• pp.686-698
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• 2021

A camouflaged encryption scheme based on Hadamard matrix and ghost imaging is proposed. In the process of the encryption, an orthogonal matrix is used as the projection pattern of ghost imaging to improve the definition of the reconstructed images. The ciphertext of the secret image is constrained to the camouflaged image. The key of the camouflaged image is obtained by the method of sparse decomposition by principal component orthogonal basis and the constrained ciphertext. The information of the secret image is hidden into the information of the camouflaged image which can improve the security of the system. In the decryption process, the authorized user needs to extract the key of the secret image according to the obtained random sequences. The real encrypted information can be obtained. Otherwise, the obtained image is the camouflaged image. In order to verify the feasibility, security and robustness of the encryption system, binary images and gray-scale images are selected for simulation and experiment. The results show that the proposed encryption system simplifies the calculation process, and also improves the definition of the reconstructed images and the security of the encryption system.

• 융합정보논문지
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• 제11권1호
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• pp.109-117
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• 2021

본 논문에서는 해양자동채염기의 구조중량 최소화를 위해 구조설계에 대한 메타모델 기반 근사최적화를 수행하였다. 구조해석은 해양자동채염기의 초기설계에 대한 강도성능을 평가하기 위해 유한요소법을 이용하여 수행하였다. 구조해석에서는 설계하중조건에 대한 강도성능을 평가하였다. 최적설계문제는 강도성능 제한조건을 만족하면서 중량을 최소화할 수 있는 구조두께의 설계변수를 결정하도록 정식화하였다. 근사최적화에는 반응표면법, 크리깅 모델 및 체비쇼프 직교 다항식의 메타모델을 사용하였다. 수치계산 특성을 검토하기 위해 근사최적화 결과는 비근사최적화 결과와 비교하였다. 근사최적화에 사용된 메타모델 중 체비쇼프 직교 다항식이 해양자동채염기의 구조설계에 가장 적합한 최적설계 결과를 나타내었다.

• 대한기계학회논문집A
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• 제24권6호
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• pp.1479-1490
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• 2000

The design process of the motor driven tilt/telescopic steering column is established by axiomatic design approach in conceptual design stage. By selecting independent design variables for improvin g performance of the steering system, each detailed design can be carried out independently. In the detailed design, the safety in crash environment and vibration reduction are considered. An occupant analysis code SAFE(Safety Analysis For occupant crash Environment) is utilized to simulate the body block test. Segments, contact ellipsoids and spring-damper elements are used to model the steering column in SAFE. The model is verified by the result of the body block test. After the model is validated, the energy absorbing components are designed using an orthogonal array. Occupant analyses are performed for the cases of the orthogonal array. Final design is determined for the minimum occupant injury. For vibrational analysis, a finite element model of the steering column is defined for the modal analysis. The model is validated by the vibration experiment. Size and shape variables are selected for the optimization process. An optimization is conducted to minimize the weight subjected to various constraints.

• 한국정밀공학회지
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• 제21권2호
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• pp.160-167
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• 2004

The correlation between the object function and the design parameter is shown on this paper by using the characteristic function for the mixed result of the structural analysis, the buckling analysis and the table of orthogonal array according to the original overhead crane's dimensional change. About the above two functions, the effectiveness of design change according to the change of design parameters could be estimated. Also, the overhead crane's weight is reduced up to 10.55 percent maintaining the structural stability according to the thickness of plate.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.162-165
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• 2004

On this study, we improved diaphgram for micro speaker performance using Taguchi method in discrete design space. The design of diaphgram has an effect on performance of micro speaker such as, thickness of diaphgram, shape of diaphgram, etc. Therefore this study carried to decide shape of diaphgram and thickness of diaphgram for minimizing 2nd natural frequency of diaphgram using Taguchi method. we showed improved design factors that minimized 2nd natural frequency of diaphgram. Also, 2nd natural frequency of diaphgram for micro speaker is reduced up to 37 percent maintaining twist mode shape. From the results of ANOVA, 2nd natural frequency of diaphgram for micro speaker have an effect on position of the outer curved shape and thickness of diaphgram.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1654-1660
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• 2000

Recently, the regulations from the government and the concerns of people give rise to the interest in exhaust and intake noise of passenger car as much as other vehicles. In these demands, performance prediction software was developed in the previous study. In this study, Robust design was used for improving the noise reduction capacity of intake system with the performance prediction software. On the basis of the existing design, length and radius of each component that was thought to effect to capacity of intake system was selected. At first factors are arranged by using $L_{18}$ table of orthogonal array and then optimum value can be obtained by $L_{16}$ table of orthogonal array.

• 한국자동차공학회논문집
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• 제4권1호
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• pp.36-54
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• 1996

This paper presents a design procedure of engine power system for vehicle. The implementation and operation environment of engine plant is somewhat diversed through the various kind of vehicles. Regarding this point, we adopt a multi-purposed design objective function which can be easily modified to reflect diverse mount design rules which have been recommended and used generally by relating fields. To search the mount parameters which provide the optimal performance, a direct search method based on an orthogonal array is developed and applied. Through several simulated results, the effectiveness of the developed disign tool is investigated and discussed.