• Journal of KIISE:Computing Practices and Letters
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• v.16 no.6
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• pp.648-653
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• 2010

The non-metric multidimensional scaling (nMDS) is a method for analyzing the relation among objects by mapping them onto the Euclidean space. The nMDS is useful when it is difficult to use the concept of distance between pairs of objects due to non-metric dissimilarities between objects. The nMDS can be regarded as an optimization problem in which there are many local optima. Since the conventional nMDS algorithm utilizes the steepest descent method, it has a drawback in that the method can hardly find a better solution once it falls into a local optimum. To remedy this problem, in this paper, we applied the simulated annealing to the nMDS and proposed a new optimization algorithm which could search for a global optimum more effectively. We examined the algorithm using benchmarking problems and found that improvement rate of the proposed algorithm against the conventional algorithm ranged from 0.7% to 3.2%. In addition, the statistical hypothesis test also showed that the proposed algorithm outperformed the conventional one.

• Journal of Korean Society for Geospatial Information Science
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• v.4 no.2 s.8
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• pp.109-121
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• 1996

It is very difficult to exchange geographical data among geographical information systems which store their spatial data with independent storage structures. Since, moreover, large amount of storage space is necessary to store spatial data and ex pen sive cost is required to input them, waste will grow as they are stored redundantly. Therefore, it is essential to share them with other geographical information systems by exchanging spatial data among them. In order to exchange spatial data efficiently, there exist several international standards for data exchange format. In this paper, we design and implement a data conversion system that converts geographical data between SDTS (Spatial Data Transfer Standard) which is adopted as the national standard for common data exchange format and Informap which is the existing mapping system. We first analyze the storage structures of SDTS and Informap, respectively and develop gateway functions according to these analyses for efficient conversion. Finally, we design and implement the overall data conversion system between SDTS and Informap using the gateway functions.

• Tunnel and Underground Space
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• v.25 no.6
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• pp.515-526
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• 2015

Predicting and measuring tunnel convergence is very crucial for estimating tunnel stability and economical construction of NATM tunnels. The method to estimate the tunnel convergence that occurs before and after construction is proposed based on literature reviews. The total displacement occurring related to tunnel construction is determined to be about 2.5 times that of measured displacements. The results of displacement measurements at two tunnels constructed with similar rock types are examined for the investigation of factors affecting the tunnel convergence. The average convergence of Gyungju A Tunnel is about 6.7 times bigger than that of Daejeon B Tunnel. The possible causes of the large convergence in Gyungju A Tunnel are suggested. In order to predict the convergence of tunnels, careful investigation of the geological structures in the ground surface and the influence of external conditions as well as careful face mapping of the tunnel face should be conducted.

• Tunnel and Underground Space
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• v.29 no.6
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• pp.508-522
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• 2019

Because of the slope failure, not only property damage but also human damage can occur, slope stability analysis should be conducted to predict and reinforce of the slope. This paper, defines the ground areas that can be characterized in terms of slope failure such as Rockmass jointset, Rockmass fault, Soil, Leakage water and Crush zone in sloped images. As a result, it was shown that the deep learning instance segmentation network can be used to recognize and automatically segment the precise shape of the ground region with different characteristics shown in the image. It showed the possibility of supporting the slope mapping work and automatically calculating the ground characteristics information of slopes necessary for decision making such as slope reinforcement.

• Journal of Korea Spatial Information System Society
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• v.2 no.2 s.4
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• pp.99-115
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• 2000

A geographic information system (GIS) generally has a great deal of geographic data and has a singular storage structure individually. It is very hard to exchange geographic data between geographic information systems which store their geographic data with incompatible formats. Moreover, since it needs large amount of storage space to store geographic data and expensive cost to input them. In this paper, we designed and implemented a SDTS (Spatial Data Transfer Standard) Data Conversion System for Gothic which is an existing geographic information system. In order to convert geographic data without loss of information, we first carefully define a mapping between SDTS data and Gothic data. Especially, since SDTS data are in the format of ISO8211, the FIPS123 library is used to access them. Because the internal data format of Gothic is not open to the public, we also use the Gothic library to access Gothic data. The SDTS data conversion system developed in this paper uses an intermediate file to convert geographic data efficiently. In addition, we use UIL (User Interface Language) to implement a graphic user interface (GUI) of our system.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.520-532
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• 2002

A new architecture called the Storage Area Network(SAN) was developed in response to the requirements of high availability of data, scalable growth, and system performance. In order to use SAN more efficiently, most SAN operating systems support storage virtualization concepts that allow users to view physical storage devices attached to SAN as a large volume virtually. A logical volume manager plays a key role in storage virtualization. In order for mapping managers to process snap-shots and reorganizations, an efficient freespace manager is required, and it affects the overall performance of logical volume. In this thesis, we design and implement a freespace manager for logical volume manager. The freespace manager efficiently allocates physical blocks for logical blocks. Also, it processes space allocation requests for supports snapshots and reorganizations.

• Journal of Korean Society for Geospatial Information Science
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• v.20 no.4
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• pp.135-143
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• 2012

Remote sensing which observes repeatedly the whole Earth and GIS-based decision-making technology have been utilized widely in disaster management such as early warning monitoring, damage investigation, emergent rescue and response, rapid recovery etc. In addition, various countermeasures of national level to collect timely satellite imagery in emergency have been considered through the operation of a satellite with onboard multiple sensors as well as the practical joint use of satellite imagery by collaboration with space agencies of the world. In order to respond heavy snowfall disaster occurred on the east coast of the Korean Peninsula in February 2011, snow-covered regions were analyzed and detected in this study through NDSI(Normalized Difference Snow Index) considering reflectance of wavelength for MODIS sensor and change detection algorithm using satellite imagery collected from International Charter. We present the application case of National Disaster Management Institute(NDMI) which supported timely decision-making through GIS spatial analysis with various spatial data and snow cover map.

• Journal of The Korean Association For Science Education
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• v.17 no.4
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• pp.461-479
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• 1997

The concept map is the diagram of two dimensions which hierachically arrays main concepts from those of the textbook and shows their relations. The research analyzed five of the ten high school earthscience textbooks approved by the Minister of Education according to the 6th reformed curriculum in 1995, one of which this research chose to make out the concept maps. The chapter [III. the Universe] contains the outer space of the earth presents new concepts about the stars and the universe and introduces the latest research in astronomy. This study changed textbook contents into Novak's concept map, searched for concepts requiring complement for learners in oder to obtain concepts from those of the textbook and pointed out problems on the basis of that result still better concept map is set up. We have the following conclusions. First, it is necessary to rule out unnecessary small units so as to make more effective understanding and to rearrange the units to have relation to contents. Second, the higher concept and lower concept need to be rearranged systematically in making an array of textbook contents. Third, the concept should have something to do with learners' experences and consciousness by showing learners the real examples relevant to the concept for the link between them.

• Journal of Digital Contents Society
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• v.11 no.1
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• pp.17-24
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• 2010

The purpose of this study is to design and implement a kernel for the support vector machine(SVM) to improve the performance of face recognition. Local feature analysis(LFA) has been well known for its good performance. SVM kernel plays a limited role of mapping low dimensional face features to high dimensional feature space but the proposed kernel using LFA is designed for face recognition purpose. Because of the novel method that local face information is extracted from training set and combined into the kernel, this method is expected to apply to various object recognition/detection tasks. The experimental results shows its improved performance.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.1
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• pp.47-54
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• 2014

Precise Point Positioning (PPP) algorithms using GPS code pseudo-range measurements were developed and their accuracy was validated for the purpose of implementing them on a portable device. The group delay, relativistic effect, and satellite-antenna phase center offset models were applied as fundamental corrections for PPP. GPS satellite orbit and clock offsets were taken from the International GNSS Service official products which were interpolated using the best available algorithms. Tropospheric and ionospheric delays were obtained by applying mapping functions to the outputs from scientific GPS data processing software and Global Ionosphere Maps, respectively. When the developed algorithms were tested for four days of data, the horizontal and vertical positioning accuracies were 0.8-1.6 and 1.6-2.2 meters, respectively. This level of performance is comparable to that of Differential GPS, and further improvements and fine-tuning of this suite of PPP algorithms and its implementation at a portable device should be utilized in a variety of surveying and Location-Based Service applications.