• Tunnel and Underground Space
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• v.30 no.4
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• pp.404-416
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• 2020

An analytical procedure for calculating the failure load of a V-shaped rock notch under two-dimensional stress conditions was developed based on the slip-line plastic analysis method. The key idea utilized in the development is the fact that the α-line, one of the slip-lines, extends from the rock notch surface to the horizontal surface outside the notch when the rock around the notch is in the plastic state, and that there exists an invariant which is constant along the α-line. Since the stress boundary condition of the horizontal surface outside the rock notch is known, it is possible to calculate the normal and shear stresses acting on the rock notch surface by solving the invariant equation. The notch failure load exerted by the wedge was calculated using the calculated stress components for the notch surface. Rock notch failure analysis was performed by applying the developed analytical procedure. The analysis results show that the failure load of the rock notch increases with exponential nonlinearity as the angle of the notch and the friction of the notch surface increase. The analytical procedure developed in this study is expected to have applications to the study of fracture initiation in rocks through wedge-shaped notch formation, calculation of bearing capacity of the rock foundation, and stability analysis of rock slopes and circular tunnels.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.33-42
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• 2016

In Korea, the address-point matching technique has been used to provide geocoding services. In fact, this technique brings the high positional accuracy. However, the quality of geocoding result can be limited, since it is significantly affected by data quality. Also, it cannot be used for the 3D address geocoding and the reverse geocoding. In order to alleviate issues, the paper has implemeted proposed geocoding methods, based on street-based addresses matching technique developed by US census bureau, for street-based addresses in Korea. Those proposed geocoding methods are illustrated in two ways; (1) street address-matching method, which of being used for not only 2D addresses representing a single building but also 3D addresses representing indoor space or underground building, and (2) reverse geocoding method, whichas converting a location point to a readable address. The result of street-based address geocoding shows 82.63% match rates, while the result of reverse geocoding shows 98.5% match rates within approximately 1.7(m) the average position error. According to the results, we could conclude that the proposed geocoding techniques enable to provide the LBS(Location Based Service). To develop the geocoding methods, the study has perfoermed by ignoring the parsing algorithms for address standardization as well as the several areas with unusual addresses, such as sub-urban areas or subordinate areas to the roads, etc. In the future, we are planning the improved geocoding methods for considering these cases.

• Journal of The Korean Society of Grassland and Forage Science
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• v.22 no.1
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• pp.1-8
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• 2002

Chufa (Cyperus esculentus L.) belongs to one of the sedge family and pows well in summer. The aboveground part of chufa is mostly consisted of leaves and the underground part is mostly composed of a clump of fibrous root with tuber. At the seeding year, it does not reproductive development but produces a lot of tuber. It produced many tillers from the tuber and grows in clumps as a bunch type. The plant height of mature chufa was 73 to 75cm and it grown fully in the middle of July. The number of tillers were increased rapidly until the end of July and still increased slowly after August but it showed very poor growth. The final fresh weight and dry matter yield of aboveground part of chufa were 40.3 tou/ha and 12.1 tou/ha. respectively. The regrowth of aboveground part was vigorous in the early stage of growth after 1st cutting but it was decreased rapidly after the second cutting. In control plot, the number of tubers per a clump were 722 at final stage and their fresh and drymatter yields per m: were 4.2kg and 1.9kg, respectively. In experimental plots, the amount of tubers was decreased steadily according to delay of cutting date, but late cutting date was not affect the tuber formation severely because the tuber produced already early in August. The nutritive value of chufa in vegetative growth stage was good but it was decreased according to growing up. The contents of crude protein(CP), neutral detergent fiber(NDF), dry matter digestibility (DMD) and total digestible nutrients(TDN) of aboveground part of chufa harvested finally were 6.1%, 51.5%, 39.8%, 33.2% and 39.4％, respectively. The contents of crude protein(CP), neutral detergent fiber(NDF), dry matter digestibility(DMD) and total digestible nutrients(TDN) of tubers of chufa were 6.1%, 81.5%, 39.8%, 33.2% and 39.4%, respectively and the content of oil was as high as 16.2%, especially.

• Journal of Korean Society for Geospatial Information Science
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• v.23 no.1
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• pp.3-14
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• 2015

As buildings in the downtown area, such as the complex building connected to the skyscraper and the underground facility, have become large and complex, the range of target domain of the space information service is rapidly expanding to the interior space; it is considered that this change will create various demands of service such as the indoor geospatial information base safety, the management of facility, and the interior navigation in the future, along with spread of mobile devices and development of IT technology. As for the indoor geospatial information, however, there is no certification standard of the established indoor geospatial information data quality, so preparing the certification standard is urgent. Thus, this study reviewed foreign and domestic research cases and prepared measures for quality verification of the indoor geospatial information to conduct a verification test of the Yeongdeungpo Station indoor geospatial information, established in 2014. As a result, through the verification test of the method and standard of the indoor geospatial information quality certification suggested by this research, it was identified that the uniform and higher quality data could be classified, and the types of error high frequently occurring could be investigated. These results are expected to be utilized as the basic data for establishing quality certification system for the indoor geospatial information in the future.

• Journal of Digital Contents Society
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• v.12 no.1
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• pp.23-32
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• 2011

For the past few years, unlike wireless widespread United States and Japan, expensive cost and platform of the mobile web carrier underground and self-centered made achievement of domestic mobile web market sluggish. Nowadays, more and more people pay attention to the mobile web service because of the increased quality of wireless internet, development of mobile device and variety of the flat-rate payment system. However, another big problem is that mobile web is too hard to use. Also, the poor content of mobile web service is an extremely serious problem. In this paper, we put forward a new method for easy to access mobile web service which is use WINC expansion numbers and users can use these numbers to shit their own website. Along with the benefits of purchase WINC number general users are able to make website and control their website at less time and energy.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.33-43
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• 2016

Grinding, weld deposition, type A sleeve, type B sleeve, composite sleeve, hot tapping and clamp are used as the method to repair the buried pipelines in the United States, UK and Europe. In the event of defect to the pipeline, they have repaired the pipeline through the fitness-for-service assessments. In addition, they have guidelines for the possible repair methods to apply to each type of damage, which is occurred due to the 3rd party construction or corrosion. According to the KGS FS551, Safety Validation in Detail including ECDA(External Corrosion Direct Assessment) as one method of integrity management should be carried out for the old pipeline which supply natural gas as the middle pressure in Korea. Where a defect on the pipelines is found, on the result of Safety Validation in Detail, the pipelines should be repaired or replaced by new piping. However, there are no guidelines or regulations regarding the repair and reinforcement of pipeline, so that, cutting the damaged pipeline and replacing it as a segment of new pipe is the only way in Korea until now. We have suggested pipeline repair methods including type A, B sleeve, composite sleeve, after the survey of foreign repair method and standards including the method of United States and the United Kingdom, and after analysis of the results on pipeline repair test including type A, type B sleeve and composite sleeve.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.42 no.3
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• pp.554-561
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• 2017

IoT (Internet of Things) devices are often located in environments where indoor or underground, signals are difficult to reach. In addition, the transmission power is low, the base station should be designed to be able to receive signals even at low reception sensitivity. For this reason, a device having a poor channel condition can be transmitted at a low data rate using a low coding rate or repetition. When the coverage class is divided according to the channel condition and the data rate, the packet length may vary from one coverage class to another, and the performance of the slotted aloha random access may be degraded. We will focus on two methods of using shared-resource and seperate resources among multiple slotted aloha methods. In particular, when devices with different coverage classes use shared resources, performance of a device with a bad channel condition may deteriorate. Conversely, when using separate resources for each coverage class, there is a problem that congestion may occur which increases the number of devices that perform random access to one resource area. In this paper, we propose some methods to overcome this problem. This study is mainly focused on MTC devices, and is considered to be a high possibility of future development.

• The KIPS Transactions:PartD
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• v.8D no.6
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• pp.657-664
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• 2001

The Information Technology has progressed to the open architecture, component, and multimedia services under Internet, ensuring interoperability, reusability, and realtime. The GIS is a system processing geo-spatial information such as natural resources, buildings, roads, and many kinds of facilities in the earth. The spatial information featured by complexity and diversity requires interoperability and reusability of pre-built databases under open architecture. This paper is for the development of component based open GIS Software. The goal of the open GIS component software is a middleware of GIS combining technology of open architecture and component ensuring interoperability of spatial information and reusability of elementary pieces of GIS software. The open GIS component conforms to the distributed open architecture for spatial information proposed by OGC (Open GIS Consortium). The system consists of data provider components, kernel (MapBase) components, clearinghouse components and five kinds of GIS application of local governments. The data provider component places a unique OLE DB interface to connect and access diverse data sources independent of their formats and locations. The MapBase component supports core and common technology of GIS feasible for various applications. The clearinghouse component provides functionality about discovery and access of spatial information under Internet. The system is implemented using ATL/COM and Visual C++ under MicroSoft's Windows environment and consisted of more than 20 components. As we made case study for KSDI (Korea Spatial Data Infrastructure) sharing spatial information between local governments, the advantage of component based open GIS software was proved. Now, we are undertaking another case study for sharing seven kinds of underground facilities using the open GIS component software.

• Tunnel and Underground Space
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• v.27 no.3
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• pp.146-160
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• 2017

$CO_2$ sequestration for alleviating global warming is a hot issue in the world. In this study, TOUGH2 and FLAC3D were combined for analyzing the hyro-mechanical coupling behaviors expected in $CO_2$ sequestration and applied it to Sleipner project carried out in Norway. In the analysis, the influence of pore pressure on in situ stress was considered and the influence of caprock permeability on hydro-mechanical behaviors was analyzed. In the condition of constant injection rate, pressure and saturation at the injection well, liquid and gas saturation in rock, major and minor stress variations with time and distance from the injection well, and horizontal and vertical displacements after injection could be investigated. The major principal stress was quickly increased in the early stage and then slowly decreased to a stable value, which was higher than the initial value. In contrast, the minor principal stress returned to initial value after some increase in the early stage. Surface upheaval was steadily increased and it was up to 15mm in 2 years after injection. When the caprock's permeability was changed from $3e-15m^2{\sim}3e-18m^2$, it was found that the injection well pressure and surface upheaval were inversely propotional to the permeability.

• Tunnel and Underground Space
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• v.30 no.2
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• pp.164-179
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• 2020

Applying the limit state design method to geotechnical structures, accuracy and reliability of its design are mainly affected by parameters for geotechnical site characteristics, such as unit weight, Poisson's ratio, deformation modulus, cohesion and frictional angle. When the structures are located in weathered ground, especially, cohesion and frictional angle of ground are closely related with decision of parameters for structures' load and ground's resistance. Therefore, the accurate determination of these parameters, which are commonly obtained from field measurement, such as borehole shear test, are essential for optimum design of geotechnical structures. The 38 case studies, in this study, have been analyzed for understanding the importance of these parameters in designing the ground structures. From these results, importance of field measurement was also ascertained. With these evaluations, an apparatus for determining the strength characteristics, which are fundamental in limit state design (LSD) method, have been newly developed. This apparatus has an improved function as following the ASTM suggestion. Through the field application of this apparatus, the strong point of minimizing the possibility of error occurrence during the measurement has been verified and authors summarized that the essential parameters for LSD can be qualitatively obtained by this apparatus for determination of strength characteristics of weathered ground.