• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.40 no.5
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• pp.403-412
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• 2022

As the 4th industrial revolution is in full swing and next-generation ICT(Information & Communications Technology) convergence technology is being developed, various smart construction technologies are being rapidly introduced in the construction field to respond to technological changes. In particular, since the earth-volume calculation process for site design accounts for a large part of the design cost at the construction site, related researches are being actively conducted to improve the efficiency of the process and accurately calculate the earth-volume. The purpose of this study is to present a method for quickly constructing the topography of a construction site in 3D and efficiently calculating earth-volume using the results. For this purpose, the construction site was constructed as a 3D realistic model using large-scale aerial photos obtained from UAV(Unmanned Aerial Vehicle). At this time, since the constructed 3D realistic model has a surface model structure in which volume calculation is impossible, the structure was converted into a 3D solid model to enable volume calculation. And we devised a methodology to calculate earth-volume based on CAD(Computer-Aided Design and Drafting) using the converted solid model. Automatically calculating earth-volume from the solid model by applying the method. As a result, It was possible to confirm a relative deviation of 1.52% from the calculated earth-volume from the existing survey results. In addition, as a result of comparative analysis of the process time required for each method, it was confirmed that the time required is reduced of 60%. The technique presented in this study is expected to be utilized as a technology for smart construction management, such as periodic site monitoring throughout the entire construction process, as well as cost reduction for earth-volume calculation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.671-678
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• 2021

In a previous study, technology protection levels were set on a qualitative basis. That study lacked quantitative standards, so here, we conduct a study to complement the previous study and to present an objective standard. This paper provides a method of setting a technical protection level that applies statistical analysis. To set the technology protection level, statistical analysis of six technical survey items is performed first. Second, the technical survey items are analyzed by AHP to quantify the opinions of experts in order to derive weights for each technical survey item. Finally, by using the normal distribution scatter map and median calculation method, the technology protection level is selected in three stages using the final detailed factor technology score reflecting the weight. The technology protection level methodology developed through this study is the first methodology with objectivity that can evaluate defense technology by level. If this methodology is applied in practice, it is believed that it will provide a scientific and quantitative technology value judgment criterion when setting the technology protection level in the future.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.536-543
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• 2011

The previous researches on railway sector have focused on the total greenhouse gas(GHG) emission through national approaches. The aim of this study was to calculate GHG emission at a local government level to measure each city's GHG intensity on rail transportation. This study followed 'the guidelines for local government greenhouse gas inventory(issued by Korea Environment Corporation)' including VKT(Vehicle kilometers Travelled) methodology for railway inventory at a metropolitan area. As a result, the gyeongsangbuk-do emitted the highest GHG emissions at a local government level, followed by chungcheongnam-do and chungcheongbuk-do in 2006. Among several cities, Gimcheon-city emitted the highest GHG at basic government level in 2006. In future, the calculation of GHG emissions at local government level can be applied to establish various policies for GHG reduction.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.554-559
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• 2011

Braking performance of a trainset that consists of a locomotive and several coaches and/or wagons is influenced by that of the locomotive as well as each coach or wagon. For trains to safely travel on a railway, trains must be provided with sufficient distance where to stop. Thus, replacing coaches or wagons needs calculating, measuring the braking performance such as a stopping distance or a deceleration. The task is further complicated if there are many kinds of trains with different braking performance characteristics. The accurate calculation is subject to acquire accurate information on the existing cars. Moreover, the initiation of braking by a driver or the geometry of the track affects as complicated factors. In this paper, based on the braking performance test conducted for US-SCRRA coaches, introduced several factors assumed to influence the result and the compensating methodology.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1201-1204
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• 2004

This paper suggests a DCS (Distributed Control System) model for steam temperature system of the thermal power plant. The model calculated within sectional range is linear. In order to calculate mathematical models, the system is partitioned into two or three sectors according to its thermal conditions, that is, saturated water/steam and superheating state. It is divided into three sections; water supply, steam generation and steam heating loop. The steam heating loop is called 'superheater' or steam temperature system. Water spray supply is the control input. A first order linear model is extracted. For linear approach, sectional linearization is achieved. Modeling methodology is a decomposition-synthetic technique. Superheater is composed of several tube-blocks. For this block, linear input-output model is to be calculated. Each tiny model has its transfer function. By expanding these block models to total system, synthetic DCS linear models are derived. Control instrument include/exclude models are also considered. The resultant models include thermal combustion conditions, and applicable to practical plant engineering field.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.04a
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• pp.17-27
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• 1995

For the post-buckling and elasto-plastic analysis of shell structures, the total Lagrangian formulation is presented based upon the degenerated shell element. Geometrically correct formulation is developed by updating the direction of normal vectors in the iteration process and evaluating the total Green-Lagrange stain corresponding U total displacements. In the calculation of the stiffness matrix, the element formulation takes into account the effect of finite rotation increments by retaining second order rotation terms in the incremental displacement field. The selective or reduced integration scheme using the heterosis element is applied in order to overcome both shear locking phenomena and the zero energy mode. The load/displacement incremental scheme is adopted for geometric non-linear F .E. analysis. Based on such methodology, the computer program is developed and numerical examples to demonstrate the accuracy and the effectiveness of the proposed shell element are presented and compared with references's results.

• Environmental Analysis Health and Toxicology
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• v.17 no.4
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• pp.347-355
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• 2002

As concerns on the effects of soil contamination on human health have grown, more efforts have been made to quantify the effects. One of such efforts is the development of risk assessment methodology. The fundamental objectives of this approach is to investigate the alternative options that reduce the risk of hazardous chemicals results from environmental pollution, which will eventually lead to an accomplishment of removement of identified toxicants in polluted environment. The U.S. EPA Risk Assessment guidance for the superfund (RAGS) provides a methods for assessing the health risk of contaminated soils and determining the preliminary remediation goals (PRGs). Using this approach, we assessed the health risk and preliminary remediation goals of petroleum contaminated site in Kyounggi province.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.51-56
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• 2005

In this paper we implemented the algorithm of methodology for calculation of spectrum requirements and analyzed the influence of traffic distribution ratio among radio access technology groups, spectral efficiency, and flexible spectrum usage margin on spectrum requirements for future development of IMT-2000 and systems beyond IMT-2000

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.5
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• pp.96-101
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• 1999

This study suggests an algorithm for tooth profile generation of free from curve involute gear, a special gear of which the pitch line is a free curve instead of a circular one. For the first, a methodology for calculation of the tooth curve is developed and formulated Then the formulated algorithm, is programmed for manufacturing and verified by computer graphics. Next the calculated results as changed in to NC codes to apply to wire electric discharge machine(WEDM). Finally, the machined gear is examined in engagement with a standard involute gear.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.623-629
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• 2001

The PSC (Propagation of Surfaces under Curvature) algorithm is adapted to the simulation of a flame propagation in a premixed medium including the effect of volume expansion across the flame front due to exothermicity. The algorithm is further developed to incorporate the flame anchoring scheme. This methodology is successfully applied to numerically simulate the response of an anchored V-flame to two strong free stream vortices, in accord with experimental observations of a passage of Karman vortex street through a flame. The simulation predicts flame cusping when a strong vortex pair interacts with flame front. In other words, this algorithm handles merging and breaking of the flame front and provides an accurate calculation of the flame curvature which is needed for flame propagation computation and estimation of curvature-dependent flame speeds.