• Journal of Advanced Navigation Technology
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• v.5 no.1
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• pp.62-73
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• 2001

In this paper, performance of DSRC systems is analyzed with considering the real roads and height of vehicles. The channels are modeled as 2-Ray and 4-Ray with a direct wave and reflected waves by a road and buildings in a physical layer because DSRC keeps LOS propagation characteristics, and the pass loss for each model is calculated respectively. Rician factor is obtained through the calculated path loss on two models for DSRC, and the performance of the systems is analyzed in AWGN and Rician fading channels, Impulsive noise and Rician fading channels respectively. As a result, in Rician fading channels with impulsive noise(A=0.2, ${\Gamma}^{\prime}=0.22$), BER is below $10^{-6}$ when the distance is farther than 80[m] and 40[m] in 2-Ray model and 4-Ray model respectively. For performance improvement, BCH coding scheme and MRC diversity scheme are adopted.

• The Journal of the Korea Contents Association
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• v.20 no.6
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• pp.415-424
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• 2020

Recently, the elevator industry in Korea has been divided into the high speed elevator market and medium-low speed elevator market, and SMEs are making rapid progress in the medium-low speed fields. Usually, since the elevator manufacturer receives an order for installation after the construction of the building structure, it is necessary to promptly create a optimal elevator model and layout drawing in an earlier stage of sales activity due to the limited time to elevator installation. This study analyzes the sale and design works of the elevator SMEs, examines the areas that can be efficiently improved, and integrates the preceding our studies from the viewpoint of efficiency improvements at sales and design business process in the elevator industry. After that, we proposed an integrated framework of sales and design process for the elevator SMEs industry, and developed a prototype software system for automating the creation of optimal elevator model, layout drawing of elevator and BOM(Bill Of Material) list.

• The Journal of the Korea Contents Association
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• v.16 no.8
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• pp.202-208
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• 2016

The scope of activities of the visually impaired is increasing. But they are not easy to visit the destination safely because the building was complicated and larger than ever. There is a guide system for visually impaired such as GPS and Audio alerts, Braille guide block, Acoustic signaller, etc. But they are not suitable for indoor because most of them are the outdoor guide system. Therefore, in this paper, I propose a system that provides guidance information to the visually impaired using Voice Technology, TTS (Text to Speech) and Haptic Technology, Beacon based on the wireless sensor networks. It informed the visually impaired of guidance information about destination such as distance, height, and obstacle to the destination using the generalized smart phone. The user could be received guide info about searches for the optimal route to the destination using the TTS technology and Haptic technology in test result of the proposed system.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.1
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• pp.155-163
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• 2010

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on-board the NASA's Terra spacecraft provides along-track digital stereo image data at 15m resolution with a base-height ratio 0.6. Automated stereocorrelation procedure was implemented using the ENVI 4.1 software to derive DEMs with $15m{\times}15m$ in 43km long and 50km wide area using the ASTER stereo images. The accuracy of DEMs was analyzed in comparison with those which were obtained from digital topographic maps of 1:25,000 scale. Results indicate that RMSE in elevation between ${\pm}7$ and ${\pm}20m$ could be achieved. Excluding cloud, water and building areas as the factors which make RMSE value exceeding 10m, the accuracy of DEMs showed RMSE of ${\pm}5.789m$. Therefore for the purpose of elevating accuracy of topographic information, we intended to detect the cloud areas and shadow areas by a landcover classification method, remove those areas on the ASTER DEM and then replace with those areas detached from the cartographic DEM by band math.

• Korean Journal of Construction Engineering and Management
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• v.13 no.3
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• pp.43-55
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• 2012

A methodology for BIM Quality Assurance in the construction industry is becoming increasingly an important issue to determine the reliability of BIM. However, the quality assurance of BIM is currently limited to check 3D models, such as clash detection and space layout while verification methods for disciplinary BIM results from structural engineering, mechanical engineering, and estimation do not exist yet. Particularly, in the BIM-based estimation mathematical equations to take off quantities are not clearly exposed so that the results are not quite accepted at practices. With the concept of reliability engineering defined in the manufacturing industry to improve reliability of outcomes of BIM-based quantity take-off, impacting factors that affect reliability of BIM-based quantity take-off were derived. It was found that the factors also include the modeling method and the features of a BIM tool. Therefore, this research aims to propose modeling and verification methods to improve reliability of BIM-based quantity take-off through the pilot test that was performed with commercial BIM tools and IFC-based BIM data.

• Explosives and Blasting
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• v.17 no.2
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• pp.36-44
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• 1999

A study was made on the design of the prediction model concerning blasting vibration in a constraction site, Namgu, Daegu City. The geology in this area consists of hornfels of shale and mud underlain by quartize, of which the main strike of the geological structure is NW direction. Measurements were carried out on the top of the wall concrete water storage tank, which is burried in the ground earth. The attenuation due to the vertical wall of the concrete structure may be experted because of spherical divergency at the bottom corner of the wall by the Huygens principle. For design of blasting prediction model, thus among scaled distance(SD) may be preferable to use in the regression model, since they represents most likely the average ground condition. Judging from the regression results, the cube root method may be more suitable for this area. The SD values for the maximum allowable vibration velocity of 0.5 cm/s, in this area are 22.5, 28.0 and 30.6 for the significance level of 50%, 95% and 99%, respectively.

• Journal of Korea Spatial Information System Society
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• v.5 no.1 s.9
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• pp.83-89
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• 2003

The GIS which is analysis of the real world to construction of 3D virtual city develop s in rapid growth. 3D virtual city is simulated by use of a GIS, Computer graphics, virtual reality and Spatial database. In this paper 3D topographical basemap which have the geographic coordinate of world was constructed by digital map. And build the Cyber city with combining the building that have elevation and 3D topographical basemap. By using server/client system for the cyber city. 3D cyber city web service implemented. We proposed the hybrid base web service method rather than the image or vector base web service. By the spatial and attribute search in the 3D Cyber City, overcome the existing simple visibility of Web 3D technology, and exhibited development direction to the Web 3D GIS.

• Journal of Korean Society of Steel Construction
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• v.26 no.3
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• pp.155-167
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• 2014

Steel-concrete composite beam has been used for a considerable time in building construction. An essential component of a composite beam is the shear connection between the steel section and the concrete slabs, which is provided by mechanical shear connectors. A variety of shapes and devices have been in use as shear connectors. This study summarizes the results of an experimental investigation involving the testing of push-out specimens with angle shear connectors. All of 22 push-out specimens were designed to study the effect of a number of parameters on the shear capacity of angle shear connectors such as the height of the angle connector, the length of welding, and the pitch of angles. Based on the test results, a design equation was developed for predicting the shear strength of angle shear connectors.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.4
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• pp.477-482
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• 1986

This trial was carried out to set up a proper drum speed of thresher to minimize the mechanical damage from threshing and thereby to obtain rye seeds possessing higher qualities for seeds. Rye plants were harvested at from 40 to 60 days after heading (DAH) with 5 days intervals and spread out on the field for 0, I, 2, 3 days for drying, respectively. After drying the plants were subjected to threshing at seven steps of drum speed from 400 to 1000 rotation per minute (RPM) of a thresher, drum diam. 18.6cm, teeth length 6cm. At 500 to 600 RPM and from the plants harvested at 55DAH with drying for one or two days, the seeds possessed low grain damage, high germinability over 90%, and field emergence rate over 80%.

• Explosives and Blasting
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• v.30 no.1
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• pp.17-28
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• 2012

Building demolitions at urban area make some inconvenience to neighborhood through generating noises, ground vibrations, and dusts. For this reason, various methods to control such environmental impacts have been being designed and practiced. Among the methods, the use of explosive demolition is rapidly increasing because it can minimize the inconveniency as well as decrease the working time and cost. In this respect, the old Sung-Nam city hall, which was a Rahmen structure comprised of beams, slabs and columns, was decided to be demolished by explosive demolition. This paper shows that explosive demolition can be the most suitable way of removing old buildings eco-friendly, safely, and economically by showing the observation results obtained from the actual demolition operation for the Sung-Nam city hall.