• Publications of The Korean Astronomical Society
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• v.27 no.3
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• pp.49-59
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• 2012

KASI (Korea Astronomy and Space Science Institute) has developed an SLR (Satellite Laser Ranging) system since 2008. The name of the development program is ARGO (Accurate Ranging system for Geodetic Observation). ARGO has a wide range of applications in the satellite precise orbit determination and space geodesy research using SLR with mm-level accuracy. ARGO-M (Mobile, bistatic 10 cm transmitting/40 cm receiving telescopes) and ARGO-F (Fixed stationary, about 1 m transmitting/receiving integrated telescope) SLR systems development will be completed by 2014. In 2011, ARGO-M system integration was completed. At present ARGO-M is in the course of system calibration, functionality, and performance tests. It consists of six subsystems, OPS (Optics System), TMS (Tracking Mount System), OES (Opto-Electronic System), CDS (Container-Dome System), LAS (Laser System) and AOS (ARGO Operation System). In this paper, ARGO-M system structure and integration status are introduced and described.

• Korean Journal of Optics and Photonics
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• v.22 no.6
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• pp.262-268
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• 2011

MIRIS(Multi-purpose Infra-Red Imaging System) is the main payload of the STSAT-3(Korea Science and Technology Satellite. 3), which is being developed by KASI(Korea Astronomy & Space Institute). EOC(Earth Observation Camera), which is one of two infrared cameras in MIRIS, is the camera for observing infrared rays from the Earth in the range of $3{\sim}5{\mu}m$. The optical system of the EOC is a Cassegrain prescription with aspheric primary and secondary mirrors, and its aperture is 100mm. A ring type flexure supports the EOC primary mirror with pre-loading in order to withstand expected load due to the shock and vibration from the launcher. Here we attempt to use the same mechanism by which a retainer supports the lens. Through opto-mechanical analysis it was confirmed that the EOC primary mirror is effectively supported.

• Journal of the Korean Geotechnical Society
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• v.28 no.9
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• pp.17-22
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• 2012

Wind blown sand is expected to disrupt the operation of the railway as the presented railway project in this paper consists of large earthworks in extreme topography of the mega dune fields. For successful railway construction in sand dune area, effective mitigation measure is the most important factor to protect the track from wind blown sand. The effective mitigation measure requires an integrated consideration of the earthworks geometry and the direct control measures such as fence system. Basically there's no perfect measure protecting railway track from wind blown sand, and it would be more economical and effective to develop robust, deliberate maintenance program for track and direct control measure on the basis of geo-morphological study. The purpose of this study is to identify the large scale geo-morphological terrains and specific sand dune morphology in the project area in UAE and estimate the direction and migration rate for sand dunes with the local variations in prevailing wind directions by undertaking literature review, and aerial photographs, satellite images, and ground studies.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5
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• pp.31-41
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• 2010

This research aims to present a methodological approach for repurposing small pockets of national/public lands, which can be constructed as parks, through an investigation of the present status of these areas of national/public lands that are scattered around Busan Megalopolis as well as the suitability of their construction. In order to attain this, this study looked at the present status of these small areas of national/public lands by utilizing a national land, city land list (lot number), land registration map and satellite image of Busan Megalopolis, and evaluating their suitability as parks through GIS analysis and classification. As a result, these small areas of lands with the potential to be turned into parks include 516 spots($375,934m^2$). Geographically, 39% of these areas are located on flat land and are the most scattered. 260 places met the requirements for optimal placement for conversion, while convenience included 305 places, and availability 267 places. The most optimal of the places meeting such standards include 61 spots. The characteristics of these areas of national/public lands include being below $500m^2$, with flatlands and open areas above a 5' grade occupy the highest ratio, accounting for 25.4% of the land studied. These results have offered a methodology for a GIS DB, which can visualize the data for a positive utilization be yond the simple level of the maintenance/preservation of national/public lands and provide basic data for the utilization and management of these types of areas in the future.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2587-2596
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• 1999

Recently, by the extension of skills like LAN, the wireless telecommunication network and the satelite services make it possible for the mobile computer users to access a database. A method to use the replicated database on a server to get new data without missing any information has been being studied. So far we have used the Static Replica Allocation(SRA) for the replication which is the method of the replication on the server. This method is to replicate the data on the replica server after a moving host is transferred to a cell. Since the network of the SRA is very good, and if there are few moving users, no trouble will happen. But if there is no moving users in a cell, the data will not be shared. Therefore, this paper is about the study of the method of relocation after replicating the data to the cells for the users(User Select Replica Allocation : USRA). We also analyze the access rate and the possibility which are closely related to the moving frequency of the mobile hosts and the numbers of the cells. As a result, We show that the 120% lower access cost and the 40%∼50% gains are achieved from the low mobility

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.792-795
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• 2008

AGT system is a kind of light railway train. AGT system use of concrete track and rubber tire, so it can be reduce the noise and vibration, compare to the normal train system. And, the dynamic responses of normal bridge are influenced by the dynamic characteristics of bridge, the speed of vehicle and the surface roughness of railway. But the AGT system bridge is influenced not only the above facts but also the guiderail unevenness, because, AGT vehicle steered by guiderail. So, in this study, optimized service condition is suggested for the design and operation of AGT system, by the means of experimental study. The experiments are executed for PSC bridge with length of 30m, at the AGT test line in Kyongsan. The test results are compared and investigated according to the prominence. In the test result, the guiderail prominence influenced on the dynamic response of bridge. It shows a increase as compared with no guiderail prominence in the dynamic response value acceleration, displacement, stain.

• Journal of Korea Spatial Information System Society
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• v.10 no.3
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• pp.55-65
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• 2008

For obtaining telematics traffic information(travel time or speed in an individual link), there are many kinds of devices to collect traffic data. Since the GPS satellite signals have been released to civil society, thank to the development of GPS technology, the GPS has become a very useful instrument for collecting traffic data. GPS can reduce the cost of installation and maintenance in contrast with existing traffic detectors which must be stationed on the ground. But. there are Problems when GPS data is applied to the existing filtering techniques used for analyzing the data collected by other detectors. This paper proposes a method to provide users with correct traffic information through filtering abnormal data caused by the unusual driving in collected data based on GPS. We have developed an algorithm that can be applied to real-time GPS data and create more reliable traffic information, by building patterns of past data and filtering abnormal data through selection of filtering areas using Quartile values. in order to verify the proposed algorithm, we experimented with actual traffic data that include probe cars equipped with a built-in GPS receiver which ran through Gangnam Street in Seoul. As a result of these experiments, it is shown that link travel speed data obtained from this algorithm is more accurate than those obtained by existing systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.4
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• pp.724-729
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• 2008

In the case of 'MAEMI', the Typhoon which formed in September, 2003, the largest-scale damage of tidal wave was caused by the co-occurrence of Typhoon surge and full tide. Until now Korea has been focusing on the calculating the amount of damage and its restoration to cope with these sea and harbor disasters. It is essential to establish some systematic counterplans to diminish such damages of large-scale tidal invasion on coastal lowlands considering the recent weather conditions of growing scale of typhoons. Therefore, the purpose of this research is to make the counterplans for prevention against disasters fulfilled effectively based on the data conducted by comparing and analyzing the accuracy between observation values and the results of estimating the greatest overflow area according to abnormal tidal levels centered on Masan area where there was the severest damage from tidal wave at that time. It's necessary utilize data like high-resolution satellite image and LiDAR(etc.) for correct analysis data considering geographical characteristics of dangerous area from the storm surge. And we must make a solution to minimize the damage by making data of dangerous section of flood into GIS Database using those data (as stated above) and drawing correcter damage function.

• Korean Journal of Remote Sensing
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• v.24 no.4
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• pp.289-298
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• 2008

An algorithm was developed to retrieve both cloud optical thickness and effective particle radius considered the aerosol effect on clouds. This study apply the algorithm of Nakajima and Nakajima (1995) that is used to retrieve cloud optical thickness and effective particle radius from visible, near infrared satellite spectral measurements. To retrieve cloud properties, Look-up table (LUT) was made under different atmospheric conditions by using a radiative transfer model. Especially the vertical distribution of aerosol is based on a tropospheric aerosol profile in radiative transfer model. In the case study, we selected the extensive forest fire occurred in Russia in May 2003. The aerosol released from this fire may be transported to Korea. Cloud properties obtained from these distinct atmospheric situations are analysed in terms of their possible changes due to the interactions of the clouds with the aerosol particle plumes. Cloud properties over the East sea at this time was retrieved using new algorithm. The algorithm is applied to measurements from the MODerate Resolution Imaging Spectrometer (MODIS) onboard the Terra spacecrafts. As a result, cloud effective particle radius was decreased and cloud optical thickness was increased during aerosol event. Specially, cloud effective particle radius is hardly greater than $20{\mu}m$ when aerosol particles were present over the East Sea. Clouds developing in the aerosol event tend to have more numerous but smaller droplets.

• Korean Journal of Remote Sensing
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• v.21 no.2
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• pp.121-133
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• 2005

Texture imaging, which means texture image creation by co-occurrence relation, has been known as one of the useful image analysis methodologies. For this purpose, most commercial remote sensing software provides texture analysis function named GLCM (Grey Level Co-occurrence Matrix). In this study, texture-imaging program based on GLCM algorithm is newly implemented. As well, texture imaging modules for GLDV (Grey Level Difference Vector) are contained in this program. As for GLCM/GLDV Texture imaging parameters, it composed of six types of second order texture functions such as Homogeneity, Dissimilarity, Energy, Entropy, Angular Second Moment, and Contrast. As for co-occurrence directionality in GLCM/GLDV, two direction modes such as Omni-mode and Circular mode newly implemented in this program are provided with basic eight-direction mode. Omni-mode is to compute all direction to avoid directionality complexity in the practical level, and circular direction is to compute texture parameters by circular direction surrounding a target pixel in a kernel. At the second phase of this study, some case studies with artificial image and actual satellite imagery are carried out to analyze texture images in different parameters and modes by correlation matrix analysis. It is concluded that selection of texture parameters and modes is the critical issues in an application based on texture image fusion.