• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.486-489
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• 2006

This paper presents a newly proposed object-oriented finite element framework and its applications on dynamic analysis of plate girder bridge. The developed framework supports various types of finite elements, materials, constraints, loads, and solution methods. One major feature different from other object-oriented finite element programs is that static model and dynamic state can be easily read from or written to a file. In addition, the framework supports efficient DOF pattern handling for a node connecting elements with different DOF patterns, new multi-point constraint handling, and various scripting languages for easy use of the library. In order to show the applicability to dynamic analysis, dynamic moving load analysis on plate girder bridge is performed.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.280-285
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• 1996

The shear behavior of reinforced concrete deep beams with web opennings has been scrutinized experimentally to verify the influences of the structural parameters such as size, shape, location and reinfrocements of web openings, and shear span ratio. A total of 22 specimens has been tested under one or two point loading conditions at the laboratory. In the tests most specimens have shown shear failures with inclined cracks from the loacing points to the supports through openings. The ultimate strengths of the specimens measured from the tests have shown wide differences depending on the locations of the openings which deter the formation of the compression struts between the loading points and the supports. The effects of the reinforcements and the geomtry of the openings on the shear strengths and the crack developments have been carefully checked and analyzed.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.7
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• pp.7-17
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• 1998

Stereolithography is a process used to rapidly produce stereolithographic parts directly from three dimensional CAD models. However design methodologies to create components to be built by stereolithography are different from those required by conventional machining processes. As a typical case in point, the support structures are required to support a component at build stage, but are later removed once building and curing are complete. These structures are used to anchor the component to the platform and to prevent sagging or distortion. This paper deals with the Support Map data structure prepared to find the appropriate regions of supports. Interferences between supports and parts, and support structure themselves as well, are checked and thus the system are searching the statically stable regions to remove the surplus support structures. Cross shaped tooth profiles are designed for easy eliminating the support structures.

• Journal of the military operations research society of Korea
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• v.30 no.2
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• pp.133-140
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• 2004

In this paper, with the limited range of ammunition supply point(ASP) at ammunition battalion in specific corps and light automobile battalion(LAB) directly supports its vehicle for ammunition supply, we propose optimal model to minimize transportation time and logistics cost using integer programming(IP) for efficient ammunition resupply allocation during a given operation period of front combat unit. And then, we consider ammunition treatment and supply capacity of ammunition supply point(ASP), constraint elements of transportation ability considering time and cost, ammunition storage capacity of combat unit, combat situation and unit mission to propose this model. Finally, through numerical example, we examine the applicable feasibility of proposed model.

• Journal of KIBIM
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• v.9 no.2
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• pp.21-28
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• 2019

Recently, many scan projects are gradually increasing for maintenance, construction. The scan data contains useful data, which can be generated in the target application from the facility, space. However, modeling the scan data required for the application requires a lot of cost. In example, the converting 3D point cloud obtained from scan data into 3D object is a time-consuming task, and the modeling task is still very manual. This research proposes Scan-to-Geometry Mapping Rule Definition (S2G-MD) which maps point cloud data to geometry for irregular building plane objects. The S2G-MD considers user use case variability. The method to define rules for mapping scan to geometry is proposed. This research supports the reverse engineering semi-automatic process for the building planar geometry from the user perspective.

• Journal of Korean Society of Steel Construction
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• v.11 no.2 s.39
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• pp.201-212
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• 1999

A beam supported by a flexible elastic support is commonly used as structural elements, e.g., braced beam, railway track, etc. The elastic support can be located in arbitrary point in the cross-section. This paper investigates the effects of support eccentricity on the elastic buckling of beams with elastic supports. The effects of stiffness of the elastic support are also studied. A beam element with elastic supports and the analysis program are developed for elastic buckling analysis using finite element formulation. The elastic support is modeled by elastic spring element. Using the offset technique, the eccentricity of support is taken into account. A beam element having 14 degrees of freedom including the warping degree of freedom is used. Various numerical example analyses show that the present formulation and analysis program accurately and effectively compute the buckling load and mode of beams with elastic supports.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.922-925
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• 2004

Bluetooth technology is essentially a method for wireless connection of a diverse set of devices ranging from PDAs, mobile phone, notebook computers, to another equipments. The bluetooth system supports both point-to-point connection and point-to-multipoint connections. In point-to-multipoint connection, the channel is shared among several bluetooth devices. Two or more devices sharing the same channel form a piconet. There is one master device and up to seven active slave devices in a piconet. The radio operates in the unlicensed 2.45GHz ISM band. This allows users who travel world-wide to use bluetooth equipments anywhere. Since the link is based on frequency-hop spread spectrum, multiple channels can exist at the same time. The Bluetooth standard has been suggested that Bluetooth equipments can be used in the short-range, maximum 100 meters . It has been defined that the time takes to setup and establish a bluetooth connection among devices is 10 seconds. It is a long time and may be a cause to lose a chance of finding other non-fixed devices. We propose a routing protocols for scatternets which can be used to control a mobile units(MUs) in this network. The proposed routing protocol is composed of two kinds of bluetooth information, access point(AP) and MU.

• Structural Engineering and Mechanics
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• v.21 no.3
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• pp.351-367
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• 2005

Multi-span beams carrying multiple point masses are widely used in engineering applications, but the literature for free vibration analysis of such structural systems is much less than that of single-span beams. The complexity of analytical expressions should be one of the main reasons for the last phenomenon. The purpose of this paper is to utilize the numerical assembly method (NAM) to determine the exact natural frequencies and mode shapes of a multi-span uniform beam carrying multiple point masses. First, the coefficient matrices for an intermediate pinned support, an intermediate point mass, left-end support and right-end support of a uniform beam are derived. Next, the overall coefficient matrix for the whole structural system is obtained using the numerical assembly technique of the finite element method. Finally, the natural frequencies and the associated mode shapes of the vibrating system are determined by equating the determinant of the last overall coefficient matrix to zero and substituting the corresponding values of integration constants into the related eigenfunctions respectively. The effects of in-span pinned supports and point masses on the free vibration characteristics of the beam are also studied.

• Structural Engineering and Mechanics
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• v.85 no.5
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• pp.665-677
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• 2023

In the present study, the limit point buckling and postbuckling behaviors of sinusoidal, shallow arches with pinned supports subjected to localized sinusoidal loading, based on the Euler-Bernoulli beam theory, are numerically analyzed. There are some studies on the buckling of sinusoidal shallow arches under the effect of sinusoidal loading. However, in these studies, the sinusoidal loading acts along the horizontal projection of the entire shallow arch. No study has been found in the relevant literature pertaining to the stability of the shallow arches subjected to various lengths of sinusoidal loading. Therefore, the purpose of this paper is to contribute to the literature by examining the effect of the length of the localized sinusoidal loading and the initial rise of the shallow arch on the limit point buckling and postbuckling behaviors. Equilibrium paths corresponding to certain values of the length of the localized sinusoidal loading and various values of the initial rise parameter are presented. It has been observed that the length of the sinusoidal loading and the initial rise parameter affects the transition from no buckling to limit point instability remarkably. The deformed configurations of the sinusoidal shallow arch under localized loading regarding buckling and postbuckling states are illustrated, as well. The effects of the length of the localized sinusoidal loading on the internal forces of the shallow arch are investigated during various stages of the loading.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.15-23
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• 2009

This paper presents a novel high-speed, low-complexity flexible 128/64-point $radix-2^4$ FFT/IFFT processor for the applications in high-throughput MIMO-OFDM systems. The high radix multi-path delay feed-back (MDF) FFT architecture provides a higher throughput rate and low hardware complexity by using a four-parallel data-path scheme. The proposed processor not only supports the operation of FFT/IFFT in 128-point and 64-point but can also provide a high data processing rate by using a four-parallel data-path scheme. Furthermore, the proposed design has a less hardware complexity compared with traditional 128/64-point FFT/IFFT processors. Our proposed processor has a high throughput rate of up to 560Msample/s at 140MHz while requiring much smaller hardware expenditure satisfying IEEE 802.11n standard requirements.