• Structural Engineering and Mechanics
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• 제13권6호
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• pp.695-711
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• 2002

Here, the dynamic response characteristics of thick cross-ply laminated composite cylindrical shells are studied using a higher-order displacement model. The formulation accounts for the nonlinear variation of the in-plane and transverse displacements through the thickness, and abrupt discontinuity in slope of the in-plane displacements at any interface. The effect of inplane and rotary inertia terms is included. The analysis is carried out using finite element approach. The influences of various terms in the higher-order displacement field on the free vibrations, and transient dynamic response characteristics of cylindrical composite shells subjected to thermal and mechanical loads are analyzed.

• Structural Engineering and Mechanics
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• 제15권4호
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• pp.463-476
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• 2003

This paper deals with nonlinear asymmetric dynamic buckling of clamped laminated angle-ply composite spherical shells under suddenly applied pressure loads. The formulation is based on first-order shear deformation theory and Lagrange's equation of motion. The nonlinearity due to finite deformation of the shell considering von Karman's assumptions is included in the formulation. The buckling loads are obtained through dynamic response history using Newmark's numerical integration scheme coupled with a Newton-Raphson iteration technique. An axisymmetric curved shell element is used to investigate the dynamic characteristics of the spherical caps. The pressure value beyond which the maximum average displacement response shows significant growth rate in the time history of the shell structure is considered as critical dynamic load. Detailed numerical results are presented to highlight the influence of ply-angle, shell geometric parameter and asymmetric mode on the critical load of spherical caps.

• 한국국방경영분석학회지
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• 제22권2호
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• pp.18-36
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• 1996

This paper provides a research on some design techniques of Industrial Engineering / Management Science (IE/MS) for more efficient logistics support in developing armament systems. It includes RAM (reliability, availability and maintainability) analysis techniques, decision making analysis techniques, human factors engineering techniques and logistics support analysis techniques.

• International Journal of Computer Science & Network Security
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• 제21권2호
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• pp.88-92
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• 2021

A method and a mathematical algorithm for finding a quasi-optimal assignment plan with rectangular efficiency matrices are proposed. The developed algorithm can significantly reduce the time and computer memory consumption for its implementation in comparison with optimal methods.

• Annals of Clinical Neurophysiology
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• 제19권2호
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• pp.77-78
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• 2017

• International Journal of Computer Science & Network Security
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• 제21권5호
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• pp.31-34
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• 2021

The article considers the possibilities of increasing the accuracy of estimates of the parameters of the trajectory of the target with the provision of a given probability of stable support of the air object, in particular, during its maneuver. The aim of the work is to develop a filtration algorithm that provides a given probability of stable tracking of the air object by determining the regular components of filtration errors, in particular, when maneuvering the air object, and their compensation with appropriate correction of filter parameters and estimates of air object trajectory parameters.

• 방송공학회논문지
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• 제27권6호
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• pp.936-939
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• 2022

최근 공중 전투체계 기술들이 발전함에 따라 대공방어 시스템의 발전이 요구되고 있다. 대공 방어 시스템의 운용개념에 있어, 표적에 적합한 무장을 선택하는 것은 제한된 대공 전력을 사용하여 위협체에 대해 효율적으로 대응한다는 측면에서 체계에 요구되는 능력 중 하나이다. 비행 위협체의 식별에 있어 많은 부분이 운용자의 육안 식별에 의존하는데 고속으로 기동하고 원거리에 위치한 비행체를 육안으로 판별하는 것은 많은 한계가 있다. 뿐만 아니라, 현대 전장에서 무인화 및 지능화된 무기체계의 수요가 증가함에 따라 운용자의 육안 식별 대신 체계가 자동으로 비행체를 식별하고 분류하는 기술의 개발이 필수적이다. 영상자료를 수집해 딥러닝 기반의 모델을 이용하여 무기체계를 식별한 사례로는 전차와 함정 등이 있지만 비행체의 식별에 대한 연구는 아직 많이 부족한 상황이다. 따라서 본 논문에서는 합성곱 신경망 모델을 이용하여 전투기, 헬기, 드론을 분류하는 모델을 제시하고 제시하는 모델의 성능을 분석한다. 본 논문에서 제시하는 모델은 시험세트에 대해 95% 이상의 정확도를 보이고, precision 0.9579, recall 0.9558, F1-socre 0.9568의 값을 나타내는 것을 확인할 수 있다.

• 한국군사과학기술학회지
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• 제27권2호
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• pp.277-284
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• 2024

For the high reliability of guidance weapon, it is important to maintain the stable supply voltage for guidance system while the bomb is gliding. However, the DC motor drive for guidance control in the low temperature can lead to the critical voltage drop due to a large inrush current. In this paper, we propose the wing deployment logic design to enhance the guidance system stability. To derive the stable drive logic based on PWM, we controlled the duty cycles for input voltage of DC motor in low temperature. The initial duty cycle was set to 40 % to relieve the inrush current. Moreover, the proper time, which is less than 1 second for controlling duty cycles, was determined by the iterative wing deployments of guidance kit. Finally, the validity of proposed logic was confirmed from the result the maximum voltage drop for the wing deployment was decreased by 23 %.

• Structural Engineering and Mechanics
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• 제24권4호
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• pp.447-461
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• 2006

Here, the axisymmetric free flexural vibrations and thermal stability behaviors of functionally graded spherical caps are investigated employing a three-noded axisymmetric curved shell element based on field consistency approach. The formulation is based on first-order shear deformation theory and it includes the in-plane and rotary inertia effects. The material properties are graded in the thickness direction according to the power-law distribution in terms of volume fractions of the constituents of the material. The effective material properties are evaluated using homogenization method. A detailed numerical study is carried out to bring out the effects of shell geometries, power law index of functionally graded material and base radius-to-thickness on the vibrations and buckling characteristics of spherical shells.

• 한국산학기술학회논문지
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• 제15권7호
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• pp.4482-4488
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• 2014

본 논문은 로봇 전역경로계획을 위하여 위협맵을 생성하는 기법을 제안한다. 로봇의 무장 정보와 적 또는 장애물의 위험정보를 비교하고 신경망 이론 기반의 학습을 수행하여 절대적인 수치로 정량화한 위협맵을 생성한다. 또한 로봇이 제안된 기법으로 생성된 위협맵을 기반으로 경로를 이동한 결과와 기존의 결과를 비교하여 로봇의 위협정도를 파악하여 성능을 검증한다.