• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.4
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• pp.385-391
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• 2014

A wheeled armored vehicle is a military vehicle that has been developed to enhance combat capabilities and mobility for the army. The wheeled armored vehicle has a high center of gravity, and it operates on unpaved and sloped roads. Therefore, this vehicle has a high risk of rollover crashes. To design the interior of the military vehicle, the crew's safety during rollover crashes is an important factor. However, actual vehicle tests for design are extremely expensive. In this paper, nonlinear dynamic analysis is performed to simulate the rollover crashes and the passenger injury is assessed for a wheeled armored vehicle. The scope of this research is the rollover condition, FE modeling of the wheeled armored vehicle and the dummy, arrangement of dummies, assessment of passenger injuries, and simulation model for rollover crashes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1702-1707
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• 2010

As quantities of the data that transmitting by the wireless are more increased, the interest and application are extending about 802.11n that uses by combination two existing 20MHz wireless LAN Channel. 802.11n use dual band of 2.4GHz band and 5.8GHz. So this is expected in mass wireless transmission method because of interference evasion effect in compliance with the radio communication of existing 2GHz neighborhood band. Like this 802.11n uses the radio as well and transmits information there is not only a possibility of undergoing an influence in radio wave environment of circumference. Specially the interior environment and outdoor environment is a possibility of saying that will be defined with each other different modeling as affects in radio communication is different. In this paper, we'll compare the influence to RF feature (802.11n) by (Indoor/Outdoor) environment difference through compared with 802.11n RF feature and Network feature in (Indoor/Outdoor) environment and also examine the correlation between RF feature and Network feature.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.2
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• pp.79-87
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• 2016

As 3D geospatial information is demanded, terrestrial laser scanners which can obtain 3D model of objects have been applied in various fields such as Building Information Modeling (BIM), structural analysis, and disaster management. To acquire precise data, performance evaluation of a terrestrial laser scanner must be conducted. While existing 3D surveying equipment like a total station has a standard method for performance evaluation, a terrestrial laser scanner evaluation technique for users is not established. This paper categorizes and analyzes error sources which generally occur in terrestrial laser scanning. In addition to the prior researches about categorizing error sources of terrestrial Laser scanning, this paper evaluates the error sources by the actual field tests for the smooth in-situ applications.The error factors in terrestrial laser scanning are categorized into interior error caused by mechanical errors in a terrestrial laser scanner and exterior errors affected by scanning geometry and target property. Each error sources were evaluated by simulation and actual experiments. The 3D coordinates of observed target can be distortedby the biases in distance and rotation measurement in scanning system. In particular, the exterior factors caused significant geometric errors in observed point cloud. The noise points can be generated by steep incidence angle, mixed-pixel and crosstalk. In using terrestrial laser scanner, elaborate scanning plan and proper post processing are required to obtain valid and accurate 3D spatial information.

• Spatial Information Research
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• v.16 no.2
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• pp.249-261
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• 2008

This study proposes a method for acquiring and managing basic information on building, which is continuously updated through construction and re-construction, in order to implement 3D-GIS based on geometric shape information and building information. First of all, distinctions between BIM and GIS information models are described, and then an overview of CityGML for virtual city and its Level of Detail are introduced. At last, a prototype for extracting building geometry from BIM data in accordance with CityGML is presented for demonstration. By using IFC data from BIM, this approach enables a lot of firms and contractors in building industry to utilize their 2D/3D, data on sites and buildings, and also to save many effects for generating exterior and interior building models which are inevitable for implementing National GIS.

• Steel and Composite Structures
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• v.37 no.2
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• pp.117-136
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• 2020

Curved steel-concrete composite box girder has been widely adopted in urban overpasses and ramp bridges. In order to investigate its mechanical behavior under complicated and combined bending, shear and torsion load, two large-curvature composite box girders with interior angles of 25° and 45° were tested under static hogging moment. Based on the strain and deflection measurement on critical cross-sections during the static loading test, the failure mode, cracking behavior, load-displacement relationship, and strain distribution in the steel plate and rebar were investigated in detail. The test result showed the large-curvature composite box girders exhibited notable shear lag in the concrete slab and steel girder. Also, the constraint torsion and distortion effect caused the stress measured at the inner side of the composite beam to be notably higher than that of the outer side. The strain distribution in the steel web was approximately linear; therefore, the assumption that the plane section remains plane was approximately validated based on strain measurement at steel web. Furthermore, the full-process non-linear elaborate finite element (FE) models of the two specimens were developed based on commercial FE software MSC.MARC. The modeling scheme and constitutive model were illustrated in detail. Based on the comparison between the FE model and test results, the FE model effectively simulated the failure mode, the load-displacement curve, and the strain development of longitudinal rebar and steel girder with sufficient accuracy. The comparison between the FE model and the test result validated the accuracy of the developed FE model.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.353-362
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• 2007

Unlike large satellites, small satellites, such as nanosatellite and microsatellite, can provide a limited interior space for components mounting. In order to mitigate this issue, the compact Bus Electronic Unit(BEU) that integrates satellite electronic modules, combining most of bus subsystems and payload electronic modules into one unit, has been developed for HAUSAT-2 nanosatellite. This paper addresses the design and environmental test result analyses of BEU. The vibration and thermal vacuum tests were conducted at qualification level for the verification of design margin of newly developed BEU. The performance of individual electronic subsystem modules has been verified through performance tests before and after the qualification tests. It was confirmed that the natural frequency of BEU satisfies the design stiffness requirement without structural damage in the vibration test. Thermal analysis results were also almost consistent with test results through modified thermal analysis modeling.

• Korean Journal of Remote Sensing
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• v.24 no.3
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• pp.223-233
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• 2008

In the mid 90's, the U.S. government released images acquired by the first generation of photo reconnaissance satellite missions between 1960 and 1972. The Declassified Intelligent Satellite Photographs (DISP) from the Corona mission are of high quality with an astounding ground resolution of about 2 m. The KH-4A panoramic camera system employed a scan angle of $70^{\circ}$ that produces film strips with a dimension of $55\;mm\;{\times}\;757\;mm$. Since GPS/INS did not exist at the time of data acquisition, the exterior orientation must be established in the traditional way by using control information and the interior orientation of the camera. Detailed information about the camera is not available, however. For reconstructing points in object space from DISP imagery to an accuracy that is comparable to high resolution (a few meters), a precise camera model is essential. This paper is concerned with the derivation of a rigorous mathematical model for the KH-4A/B panoramic camera. The proposed model is compared with generic sensor models, such as affine transformation and rational functions. The paper concludes with experimental results concerning the precision of reconstructed points in object space. The rigorous mathematical panoramic camera model for the KH-4A camera system is based on extended collinearity equations assuming that the satellite trajectory during one scan is smooth and the attitude remains unchanged. As a result, the collinearity equations express the perspective center as a function of the scan time. With the known satellite velocity this will translate into a shift along-track. Therefore, the exterior orientation contains seven parameters to be estimated. The reconstruction of object points can now be performed with the exterior orientation parameters, either by intersecting bundle rays with a known surface or by using the stereoscopic KH-4A arrangement with fore and aft cameras mounted an angle of $30^{\circ}$.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.2
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• pp.263-272
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• 2019

This study demonstrates the applicability of the FLO-2D for the influence analysis of the debris flow on expressway. To do this, the behavior of debris flow on the expressway was reproduced by applying the FLO-2D to actual generated debris flow. The study area is a part of the Deokyusan Service Area on the Daejon-Jinju Expressway, where traffic was blocked for 24 hours due to the debris flow in August 2005. Geographical analysis with GIS, hydrological analysis with HEC-HMS, and estimation of the amount of debris flow were carried out using field survey and soil property test data. Then, the optimum parameter combination of FLO-2D was selected through the parameter sensitivity analysis, and the behavior analysis of debris flow on expressway was applied. The comparison of the predictions with the observations shows the availability of FLO-2D for the behavior analysis of debris flow on the expressway.

• The Journal of Bigdata
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• v.3 no.2
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• pp.35-49
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• 2018

It seems unrealistic to say that fried chicken, often known as the American soul food, has one of the biggest markets in South Korea. Yet, South Korea owns more numbers of fried chicken restaurants than those of McDonald's franchise globally[4]. Needless to say not all these fast-food commerce survive in such small country. In this study, we propose a predictive model that could potentially help one's decision whilst deciding to open a store. We've extracted all fried chicken restaurants registered at the Korean Ministry of the Interior and Safety, then collected a number of features that seem relevant to a store's closure. After comparing the results of different algorithms, we conclude that in order to best predict a store's survival is FDA(Flexible Discriminant Analysis). While Neural Network showed the highest prediction rate, FDA showed better balanced performance considering sensitivity and specificity.

• The Korean Journal of Franchise Management
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• v.11 no.1
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• pp.19-29
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• 2020

Purpose - To understand the assessment basis of customers' coffee shop experience and give more practical advices to the franchised coffee shops which are poorly managed in the competitive market, this study identified factors to measure the quality of customer experience and explored the relationship between these factors and customer satisfaction and loyalty. Further, this study analyzed which role self-efficacy played in the structural relationship between the quality assessment factors, satisfaction and loyalty of franchised coffee shops. Research design, data, methodology - The data were collected from respondents who had visited franchised coffee shops within the previous month through online survey. The questionnaires were surveyed from February 11 to February 14, 2019. A total of 318 responses were collected after excluding four of incomplete or uncandid responses. A structural equation modeling approach was used to examine the proposed hypothesis and a confirmatory factor analysis was employed to verify the four dimensions of quality assessment. Results - The findings of this study are as follows. First, the three of quality assessment variables significantly influenced on satisfaction except environmental quality. Second, economic and service quality significantly influenced on self-efficacy but environmental and menu quality didn't. Third, satisfaction significantly influenced on loyalty but not on self-efficacy. Fourth, self-efficacy significantly influenced on Loyalty. Conclusions - This study identified the four dimensions to assess the franchised coffee shop service - menu, environment, service and economic quality and verified these four dimensions are valid as indicators to measure the quality of customers' coffee shop experience. Further, by empirically testing the structural relationships among these quality assessment dimensions, satisfaction, self-efficacy and loyalty, this study provided theoretical foundations to explore the relationship between customer and the franchised stores in restaurant businesses. For the industry, the study findings showed that customers highly appreciated menu and economic quality of the service rather than the stores' interior. This indicate that the franchised coffee shops need to focus more on the basics of coffee such as taste and menu variety and economic value than the decoration of the store, which are often over-invested nowadays.