• Coupled systems mechanics
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• v.11 no.2
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• pp.133-149
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• 2022

The accurate prediction of elastoplasticity under prescribed workloads is essential in the optimization of engineering structures. Mechanical experiments are carried out with the goal of obtaining reliable sets of material parameters for a chosen constitutive law via inverse identification. In this work, two sample geometries made of high strength steel plates were evaluated to determine the optimal configuration for the identification of Ludwik's nonlinear isotropic hardening law. Finite element model updating(FEMU) was used to calibrate the material parameters. FEMU computes the parameter changes based on the Hessian matrix, and the sensitivity fields that report changes of computed fields with respect to material parameter changes. A sensitivity analysis was performed to determine the influence of the sample geometry on parameter identifiability. It was concluded that the sample with thinned gauge region with a large curvature radius provided more reliable material parameters.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1153-1155
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• 2017

The Launch Vehicle is made up of one system with several parts gathered together. In order to make the various parts developed in various organizations into one system, it is necessary to confirm all designs at certain point in time. Change after the design fix require controlled process to analyze the impact of the changes, to decide whether or not to make the change, and to verify that the change was implemented as intended. The configuration management procedure implemented in the above manner is also applied to the development process of KSLV-II. The CAD tool and PLM are linked with each other to perform configuration management for the 3D model, 2D drawing, and the configuration identification document.

• International Journal of Control, Automation, and Systems
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• v.4 no.4
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• pp.486-494
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• 2006

In this paper, we present the complete isotropy analysis of a caster wheeled omnidirectional mobile robot (COMR) with nonredundant/redundant actuation. It is desirable for robust motion control to keep a COMR close to the isotropy but away from the singularity as much as possible. First, with the characteristic length introduced, the kinematic model of a COMR is obtained based on the orthogonal decomposition of the wheel velocities. Second, a general form of the isotropy conditions of a COMR is given in terms of physically meaningful vector quantities which specify the wheel configuration. Third, for all possible nonredundant and redundant actuation sets, the algebraic expressions of the isotropy conditions are derived so as to identify the isotropic configurations of a COMR. Fourth, the number of the isotropic configurations, the isotropic characteristic length, and the optimal initial configuration are discussed.

• Journal of the military operations research society of Korea
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• v.25 no.1
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• pp.87-106
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• 1999

There are many technical datum in related with design, test & evaluation and logistic support which will be exchanged between geographically isolated units and heterogeneous hardwares & softwares in developing and operating the weapon systems. The paper proposes the conceptual database schema to establish configuration management information systems in which these datum can be automatically interchanged, tracked, audited and status-accounted without errors under the various environments. The paper investigates how to identify and classify the data in accordance with document identification, task analysis, system development, logistic support, system test & evaluation and data management. Furthermore, the investigation includes drawing the subject areas and modeling the conceptual database schema to explain the relationships between these datum. Thus, the paper results in the conceptual framework and data models of configuration management information systems, while additional customization efforts be required in applying the models to a specific weapon systems R&D.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.5
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• pp.494-500
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• 2010

In this paper, we newly propose a wireless optical identification system and carried out experiments. A wireless optical identification system consists of a reader and a transponder. The configuration of a reader is the same as that of a transponder, which uses LED light as transmission media and detects the signal light with a solar cell. Optical alignment with a lens is not required because the absorption area of a solar cell is wide and flat, and it is very easy to attach a solar cell on the surface of an object. As the light wavelength does not interfere with radio frequency, a wireless optical identification system shows stable operation. In experiments, we realized a wireless optical identification system that automatically identifies the transponder data at a distance of 1 m using solar cells.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.9 no.3
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• pp.108-112
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• 1984

The motivation in this paper is in obtaining an adaptive observer with simple configuaration and faster adapting speed. The identification and state estimation are seperated to increase the adapting speed of the adaptive observer. The method of identification proposed by Ichikawa is modified. And the adaptive observer is constructed by using the output of state variable filters that are used in identification. Finally, the digital simulation results to the proposed system are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.9
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• pp.903-909
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• 2007

Mobile Robots are increasingly being used to perform tasks in unknown environment. The potential of robots to undertake such tasks lies in their ability to intelligently and efficiently search in an environment. To achieve autonomous mobile robot navigation, efficient path planner and accurate localization technique are the fundamental issues that should be addressed. This paper presents mobile robot localization using IRID(InfraRed IDentification) as artificial landmarks. IRID has highly deterministic characteristics, different from RFID. By putting several IRID emitters on the ceiling, the floor is divided into many different sectors and each sector is set to have a unique identification. Dead-reckoning provides the estimated robot configuration but the error becomes accumulated as the robot travels. IRID information tells the sector the robot is in, but the size of the uncertainty is too large if only the IRID information is used. This paper presents an algorithm which combines both the encoder and the IRID information so that the size of the uncertainty becomes smaller. It also introduces a framework which can be used with other types of the artificial landmarks. The characteristics of the developed IRID and the proposed algorithm are verified from the simulation results and experiments.

• Journal of English Language & Literature
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• v.55 no.3
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• pp.441-458
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• 2009

The Imperial Road is Jean Rhys s unfinished manuscript, rejected by publishers for its openly racist tone. Although it describes Rhys s actual visit to Dominica in 1936, it is not a transparent recollection of the travel but a recreation informed by racial dynamics of the 1970s when she wrote the text. This paper examines the manuscript as a troubled (and troubling) response to what Rhys perceived as racial rejection from Dominica at the wake of political independence. Rhys s representation of white Creole womanhood significantly depends on an interwoven configuration of racial dynamics and sexual politics, where an oppressive white European man facilitates a white Creole woman s cross-racial identification with Afro-Caribbeans. However, the political and literary landscape of the West Indies in the 1970s made such cross-racial identification untenable. As a result, The Imperial Road is full of disturbing racial hatred, prejudice, and resentment. And yet, it also reflects Rhys s honest and serious concern over a white Creole s racial identity in postcolonial Dominica, raising a difficult question: How would a postcolonial age change a white Creole identity that belongs neither to the colonized nor to the colonizer (or both)? In The Imperial Road, unable to identify with Afro-Caribbeans, the white Creole is disoriented in time and space, lost at home, stuck between the past and the present, not knowing how to participate in a postcolonial homeland. Through the narrator s racial disorientation, The Imperial Road exposes the white Creole s fundamental dependence on other Creoles.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.1 s.256
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• pp.43-49
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• 2007

A new electric coil design methodology using the notion of topology optimization is developed. The specific design problem in consideration is to find optimal coil configuration that maximizes the Lorentz force under given magnetic field. Topology optimization is usually formulated using the finite element method, but the novel feature of this method is that no such partial differential equation solver is employed during the whole optimization process. The proposed methodology allows the determination of not only coil shape but also the number of coil turns which is not possible to determine by any existing topology optimization concept and to perform single coil strand identification algorithm. The specific applications are made in the design of two-dimensional fine-pattern focusing coils of an optical pickup actuator. In this method, the concept of equivalent magnetizing current is utilized to calculate the Lorentz force, and the optimal coil configuration is obtained without any initial layout. The method is capable of generating the location and shape of turns of coil. To confirm the effectiveness of the proposed method in optical pickup applications, design problems involving multipolar permanent magnets are considered.

• Smart Structures and Systems
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• v.30 no.6
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• pp.583-599
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• 2022

In this paper, a multi-objective wireless sensor network configuration optimization method is proposed. The proposed method aims to determine the optimal information and lifespan wireless sensor network for structural health monitoring of large-scale infrastructures. In particular, cluster-based wireless sensor networks with multi-type of sensors are considered. To optimize the lifetime of the wireless sensor network, a cluster-based network optimization algorithm that optimizes the arrangement of cluster heads and base station is developed. On the other hand, based on the Bayesian inference, the uncertainty of the estimated parameters can be quantified. The coefficient of variance of the estimated parameters can be obtained, which is utilized as a holistic measure to evaluate the estimation accuracy of sensor configurations with multi-type of sensors. The proposed method provides the optimal wireless sensor network configuration that satisfies the required estimation accuracy with the longest lifetime. The proposed method is illustrated by designing the optimal wireless sensor network configuration of a cable-stayed bridge and a space truss.