• KIPS Transactions on Software and Data Engineering
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• v.3 no.5
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• pp.179-186
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• 2014

Current networks such as social network, web page link, traffic network are big data which have the large numbers of nodes and edges. Many applications such as social network services and navigation systems use these networks. Since big networks are not fit into the memory, existing in-memory based analysis techniques cannot provide high performance. Frontier-Expansion-Merge (FEM) framework for graph search operations using three corresponding operators in the relational database (RDB) context. FEM exploits an index table that stores pre-computed partial paths for efficient shortest path discovery. However, the index table of FEM has low hit ratio because the indices are determined by distances of indices rather than the possibility of containing a shortest path. In this paper, we propose an method that construct index table using high degree nodes having high hit ratio for efficient shortest path discovery. We experimentally verify that our index technique can support shortest path discovery efficiently in real-world datasets.

• The Korean Journal of Community Living Science
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• v.22 no.4
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• pp.579-590
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• 2011

This study focused on developing various application services for smart phones in the rural amenity resources information service. By developing application services for smart phones, this study aims to stimulate rural tourism and increase the rural tourism economy. The main findings of this study revealed that 'information for reports/cultural/recreational facilities, etc', 'maps for rural villages(food, attractions, etc)', 'regional weather information', 'traffic reports for rural villages(public transportation, etc)' and 'introduction of rural experiences (festivals, exhibitions, events, etc)' are preferentially needed as the contents services of the rural amenity resources. Moreover, it has been found that the types of services firstly needed to offer information of rural amenity resources include 'searching the information around me(where I am)', 'wayfinding such as navigation', 'information sharing function with messenger and SNS, etc', 'taking and editing photography', 'searching information of rural villages about festivals, events, etc'. These are the items that can be utilized in developing application services needed by information services of rural amenity resources. It is expected that the future real-time smart phone services for rural amenity resources will be able to reinforce the competitiveness of rural tourism by giving urban dwellers the chance to utilize the customized information whenever they want.

• Journal of the Korea Society of Computer and Information
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• v.19 no.2
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• pp.91-99
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• 2014

This paper is about design and implementation of 'SeaMap' importer module which is for map-based application using 'SeaMap' data. 'SeaMap' data importer is a module that reads 'SeaMap' data in consistent form and offers using easily change the format and the internal data structure in the application. Design of data importer module is based on analyzing characteristic of 'SeaMap'. The comparative analysis between the data type of 'SeaMap' and standard S-57 Electronic Navigation Chart (ENC) of the International Hydrographic Organization (IHO), based on this, to be applicable of S-52 standards 'SeaMap' data is defined as a structure of data. The importer module is designed and converted to allow to use distribution type of 'SeaMap' data sets in map application, parsing 'SeaMap' data around the object defining transformation data structure. In addition, we implemented a 'SeaMap' data viewer in order to test our 'SeaMap' data importer module.

• Spatial Information Research
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• v.19 no.6
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• pp.55-65
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• 2011

All of area we live in has its own geographic names. Even small size of rock under the water has its own name. They are called "marine geographic names". Marine geographic names can be classified two categories. One is a proper name; the other is an attribute name. Rocks, reefs and banks referred in the introduction, belong to the category of the attribute name. And there are certain standards to name marine geographic things. In this study, we conducted a case research with the aims to figure out how we name and use those three features that we consider dangerous factors for marine navigation. This study also focused on differences between the methods used to classify attributes of marine geographic names in the past and today. In addition, it reviewed and analyzed marine geographic names used by Korea Hydrographic and Oceanographic Administration (KHOA) on its own Nautical charts and conducted a case research on marine geographic names notified by Korean Committee on Marine Geographic Names. Based on research and analysis, this study presents future methods regarding marine geographic names standardization.

• Phonetics and Speech Sciences
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• v.7 no.3
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• pp.139-149
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• 2015

This paper aims to analyze pronunciation variations of loanwords produced by Korean and improve the performance of pronunciation modeling of loanwords in Korean by using syllable-based segmentation and phonological knowledge. The loanword text corpus used for our experiment consists of 14.5k words extracted from the frequently used words in set-top box, music, and point-of-interest (POI) domains. At first, pronunciations of loanwords in Korean are obtained by manual transcriptions, which are used as target pronunciations. The target pronunciations are compared with the standard pronunciation using confusion matrices for analysis of pronunciation variation patterns of loanwords. Based on the confusion matrices, three salient pronunciation variations of loanwords are identified such as tensification of fricative [s] and derounding of rounded vowel [ɥi] and [$w{\varepsilon}$]. In addition, a syllable-based segmentation method considering phonological knowledge is proposed for loanword pronunciation modeling. Performance of the baseline and the proposed method is measured using phone error rate (PER)/word error rate (WER) and F-score at various context spans. Experimental results show that the proposed method outperforms the baseline. We also observe that performance degrades when training and test sets come from different domains, which implies that loanword pronunciations are influenced by data domains. It is noteworthy that pronunciation modeling for loanwords is enhanced by reflecting phonological knowledge. The loanword pronunciation modeling in Korean proposed in this paper can be used for automatic speech recognition of application interface such as navigation systems and set-top boxes and for computer-assisted pronunciation training for Korean learners of English.

• Journal of the Korean Society of Marine Environment & Safety
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• v.14 no.3
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• pp.219-225
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• 2008

Since July 2006, marine traffic safety management system have been enforced to support the vessels transiting across the coastal area and the vessels coming in and out of ports in southwestern coastal area where heavy traffic density and marine casualties occurred frequently. The marine traffic volume for the marine traffic environmental assessment was measured by the information from RADAR and AIS system in the area. The distributions of marine casualties were analyzed in the main routes and traffic separation schemes during the last five years and the navigational dangerous elements were investigated with the influence of natural environment, the distribution of fisheries and survey questionnaire. Marine accidents of merchant ships have a tendency to decrease gradually but in case of fishing boats, the rate of marine accidents have a contrary results in this area during the last five years. The dangerous elements on navigation appeared to be the dense force from June to August, fisheries activities and the vessels which not follow the compulsory watch on VHF-band radio communication equipments.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.2
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• pp.131-138
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• 2017

Lately, Internet-based vessels have begun to appear at sea with the development of ICT. Thereby crews have gained easy Internet access through increased smartphone portability. However, the side effects of smartphone use while on watch, have not been studied seriously despite being a reality. In this study, simulation experiments were carried out using a Ship Handling Simulator in order to distinguish the risks of using a smartphone while on watch. Proximity Evaluation, Control Evaluation, Subjective Evaluation and Situation Awareness to the dangerous situation were used to quantify risk during simulation, and analysis results were compared with cases when using and not using a smartphone. It was found that the degree of risk increased between 1.3 to 3 times given smartphone use. Consequently, this paper represents foundation for the restriction of smartphone use and proposes smartphone usage guideline for ship navigation.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.173-182
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• 2005

In this paper, we propose a landmark recognition method which is irrelevant to the camera viewpoint on the navigation for localization. Features in previous research is variable to camera viewpoint, therefore due to the wealth of information, extraction of visual landmarks for positioning is not an easy task. The proposed method in this paper, has the three following stages; first, extraction of features, second, learning and recognition, third, matching. In the feature extraction stage, we set the interest areas of the image. where we extract the corner points. And then, we extract features more accurate and resistant to noise through statistical analysis of a small eigenvalue. In learning and recognition stage, we form robust feature models by testing whether the feature model consisted of five corner points is an invariant feature irrelevant to viewpoint. In the matching stage, we reduce time complexity and find correspondence accurately by matching method using similarity evaluation function and Graham search method. In the experiments, we compare and analyse the proposed method with existing methods by using various indoor images to demonstrate the superiority of the proposed methods.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.22 no.3
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• pp.285-291
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• 2004

GPS photogrammetry or the GPS/INS photogrammetry, which are based on the direct measurement of the projection centers and attitude at the moment of camera exposure time through loading the GPS receiver or INS in aircraft. Both photogrammetric methods can offer us to acquire the exterior orientation parameters with only minimum ground control points, even the ground control process could be completely skipped. Consequently, we can drastically reduce the time and cost for the mapping process. In this thesis, test flight was conducted in Suwon area to evaluate the performance of accuracy and efficiency through the analysis of results among the three photogrammetric methods, that is, traditional photogrammetry, GPS photogrammetry and GPS/INS photogrammetry. Test results shows that a large variety of advantages of GPS photogrammetry and GPS/INS photogrammetry against traditional photogrammetry is to be verified. Especially, the number of ground control points for the exterior orientation could be saved more than 70～80%, respectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.20 no.2
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• pp.119-126
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• 2002

Recently, as advancing the technologies for Web 3D and Virtual Reality, the studies have been progressed actively to provide three dimensional information on the web. Especially, the various applications for providing urban information in 3D space have been developed using EAI(External Authoring Interface) that serves an interface between VRML(Virtual Reality Modeling Language), standard language for embodying virtual reality, and JAVA applet in HTML. In this study, as constructing 3D virtual city information using Digital Map, IKONOS satellite image, VRML and so on, we could provide users which need several information with building location and various urban living information. In addition, applying 3D skills such as texturing, panorama and navigation, users were enabled to perform various route searching and scenery analysis. Finally, to serve urban living information in real time, we designed to search information faster through interfacing database and to update data using ASP(Active Server Page) on web.