• Annual Conference of KIPS
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• 2009.04a
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• pp.1167-1169
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• 2009

Multipath routing in wireless sensor networks has been proven to provide with increased data delivery ratio, security, robustness to node and link failures, network throughput, etc. However, the energy cost for multiple routes construction and their maintenance is very high. This paper proposes a sink-initiated, node-disjoint multipath routing protocol for static wireless sensor networks that significantly minimizes the route construction messages and thereby saves the critical batter energy of sensor nodes. It also distributes the traffic load spatially over many nodes in the forwarding paths, which ensures balanced energy consumption in the network and thereby increases the network lifetime. The simulation results show that it decreases the routing overhead as well as the standard deviation of nodes' residual energies.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.56-69
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• 2005

In this paper, it is clearly shown that the two well-known necessary and sufficient conditions mp n as generic static output feedback pole-assignment and mp + d(m+p) n+d as generic minimum d-th order dynamic output feedback pole-assignment on complex field, unbelievably, do not match up each other in strictly proper linear systems. For the analysis, a diagram analysis is newly created (which is defined by the analysis of 'convoluted rectangular/dot diagrams' constructed via node-branch conversion of the signal flow graphs of output feedback gain loops). Under this diagram analysis, it is proved that the minimum d-th order dynamic output feedback compensator for pole-assignment in m-input, p-output, n-th order systems is quantitatively decomposed into static output feedback compensator and its associated d number of arbitrary 1st order dynamic elements in augmented (m+d)-input, (p+d)-output, (n+d)-th order systems. Total configuration of the mismatched data is presented in a Table.

• Structural Engineering and Mechanics
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• v.12 no.5
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• pp.491-506
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• 2001

In this paper, a new three-dimensional piezoelectric thin shell element containing an integrated distributed piezoelectric sensor and actuator is proposed. The distributed piezoelectric sensor layer monitors the structural shape deformation due to the direct effect and the distributed actuator layer suppresses the deflection via the converse piezoelectric effect. A finite element formulation is presented for static response of laminated shell with piezoelectric sensors/actuators. An eight-node and forty-DOF shell element is built. The performance of the shell elements is improved by reduced integration technique. The static shape control of structure is derived. The shell element is verified by calculating piezoelectric polymeric PVDF bimorph beam. The results agreed with those obtained by theoretical analysis, Tzou and Tseng (1990) and Hwang and Park (1993) fairly well. At last, the static shape control of a paraboloidal antenna is presented.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.107-114
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• 2004

In this paper, a simple improved 8-node finite element for the finite element analysis of fibrous composite plates is presented by using the direct modification. We drive explicit expressions of shape functions for the 8-node element with bilinear element geometry, which is modified so that it can represent any quadratic fields in Cartesian coordinates. The refined first-order shear deformation theory is proposed, which results in parabolic through-thickness distribution of the transverse shear strains and stresses from the formulation based on the third-order shear deformation theory. It eliminates the need for shear correction factors in the first-order theory. This finite element is further improved by combined use of assumed strain, modified shape function, and refined first-order theory. To show the effectiveness of our simple modification on the 8-node finite elements, numerical studies are carried out the static, buckling and free vibration analysis of fibrous composite plates.

• Structural Engineering and Mechanics
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• v.35 no.6
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• pp.677-697
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• 2010

This paper focuses on geometrically non-linear static analysis of a simply supported beam made of hyperelastic material subjected to a non-follower transversal uniformly distributed load. As it is known, the line of action of follower forces is affected by the deformation of the elastic system on which they act and therefore such forces are non-conservative. The material of the beam is assumed as isotropic and hyperelastic. Two types of simply supported beams are considered which have the following boundary conditions: 1) There is a pin at left end and a roller at right end of the beam (pinned-rolled beam). 2) Both ends of the beam are supported by pins (pinned-pinned beam). In this study, finite element model of the beam is constructed by using total Lagrangian finite element model of two dimensional continuum for a twelve-node quadratic element. The considered highly non-linear problem is solved by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. In order to use the solution procedures of Newton-Raphson type, there is need to linearized equilibrium equations, which can be achieved through the linearization of the principle of virtual work in its continuum form. In the study, the effect of the large deflections and rotations on the displacements and the normal stress and the shear stress distributions through the thickness of the beam is investigated in detail. It is known that in the failure analysis, the most important quantities are the principal normal stresses and the maximum shear stress. Therefore these stresses are investigated in detail. The convergence studies are performed for various numbers of finite elements. The effects of the geometric non-linearity and pinned-pinned and pinned-rolled support conditions on the displacements and on the stresses are investigated. By using a twelve-node quadratic element, the free boundary conditions are satisfied and very good stress diagrams are obtained. Also, some of the results of the total Lagrangian finite element model of two dimensional continuum for a twelve-node quadratic element are compared with the results of SAP2000 packet program. Numerical results show that geometrical nonlinearity plays very important role in the static responses of the beam.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.83-87
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• 2007

Correlation Propagation Neural Networks is proposed for On-line interpolation. The proposed neural network technique is the real time computation method through the inter-node diffusion. In the network, a node corresponds to a state in the quantized input space. Each node is composed of a processing unit and fixed weights from its neighbor nodes as well as its input terminal. Information propagates among neighbor nodes laterally and inter-node interpolation is achieved. Through several simulation experiments, real time reconstruction of the nonlinear image information is processed. 1-D CPNN hardware has been implemented with general purpose analog ICs to test the interpolation capability of the proposed neural networks. Experiments with static and dynamic signals have been done upon the CPNN hardware.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.833-839
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• 2010

Mobility of sensor node is one of the rising issues in Wireless Sensor Networks (WSN). However, current security researches on WSN only consider static environments. Thus they are not sufficient to be deployed in the dynamic environment where the resource is limited. In this paper, we propose the efficient node authentication and key exchange protocol that reduces the overhead in node re-authentication.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.431-434
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• 2006

센서 네트워크(Sensor Network)는 항공기(Aircraft)로 살포되는 센서 노드(Sensor Node)들로 구성된다. 자연적인 장애물 즉, 바람, 나무 등이나 빌딩과 같은 조형물로 인해 적절한 위치에 센서 노드들이 배치되지 못하여 불필요한 에너지 소비와 전송 지연 등이 발생하게 된다. 본 논문에서는 기존 논문에서 사용하던 고정 노드(Static Node) 뿐만 아니라 이동 노드(Mobile Node)를 센서 필드(Sensor Field)에 배치 할 것이다. 각 센서 노드의 정보를 싱크(Sink)노드가 수집 분석 후 본 논문에서 제시한 제안에 따라 이동 노드 위치 변경하여 센서 네트워크 라우팅(Routing)의 성능을 향상시키는 방법을 제안한다.

• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.461-464
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• 1998

Lateral Information Propagation Neural Networks (LIPN) is proposed for on-line interpolation. The proposed neural network technique is the real time computation method through the inter-node diffusion. In the network, a node corresponds to a state in the quantized input space. Each node is composed of a processing unit and fixed weights from its neighbor nodes as well as its input terminal. Information propagates among neighbor nodes laterally and inter-node interpolation is achieved. Through several simulation experiments, real time reconstruction of the nonlinear image information is processed. 1-D LIPN hardware has been implemented with general purpose analog ICs to test the interpolation capability of the proposed neural networks. Experiments with static and dynamic signals have been done upon the LIPN hardware.

• Advances in materials Research
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• v.12 no.2
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• pp.83-100
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• 2023

In this paper, sandwich plate, constructed with orthotropic and isotropic composite materials, is analyzed to obtain the static and harmonic behavior. The analysis is done by using ANSYS APDL FEM tool. A solid-shell 190 and an 8-node solid 185 elements are employed for face and core material respectively to analyze the plate. Results was attained by using Reissner-Mindlin theory. Effect of increasing thickness ratio of face sheet to depth of the plate is presented on static, vibration and harmonic response on the sheet and the results are discussed briefly. Published work in open domain was used to validate the results and observed excellent agreement. It can be stated that proposed model presents results with remarkable accuracy. Results are obtained to reduce the weight of the plate and minimizing the vibration amplitudes.