• Tunnel and Underground Space
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• v.11 no.1
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• pp.64-71
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• 2001

The purpose of this study is to develop rail rockfall and landslide information system to manage spatial database using GIS. For this, a spatial database containing information such as railroad, map, topographic analysis, meteorological data, and rockfall has been constructed for 2.5 km or 5 km buffer zone from the Kyungchun, Youngdong, Jungang, Taebak and Jungsun Rairoad where risk of landslide occurrence potential is high. For management of the spatial database, railroad rockfall and landslide information system has been developed. The information system consists of view, table, chart, layout and project environment. The functions provided in the system are data conversion, editing, labeling, zoom in and out, map making, graphic editing, text DB management, charting, on-line help as well as input, retrieve and output of spatial database. The system was developed using ArcView script language Avenue, and consisted of pull-down menus and icons for easy use. The spatial database and the information system can be used to rockfall and landslide management and analysis near the railroad as basic data and tool.

• Journal of the Korean Association of Geographic Information Studies
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• v.7 no.4
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• pp.1-14
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• 2004

In this study, we propose Linktable based on extended TB-Tree(LTB-Tree) which can improve the performance of existing TB (Trajectory-Bundle)-tree proposed for indexing the trajectory of moving objects in GIS Applications. In addition, in order to evaluate proposed indexing scheme, we take into account as follows. At first, we select existing R*-tree, TB-tree, and LTB-tree as the subject of performance evaluation. Secondly, we make use of random data set and real data set as experimental data. Thirdly, we evaluate the performance with respect to the variation of size of memory buffer by considering the restriction of available memory of a given system. Fourth, we test them by using the experimental data set with a variation of data distribution. Finally, we think over insertion and retrieval performance of trajectory query and range query as experimental measures. The experimental results show that the proposed indexing scheme, LTB-tree, gains better performance than traditional other schemes with respect to the insertion and retrieval of trajectory query.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.12
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• pp.58-65
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• 2008

This paper presents a new geographic distributed hash table (GDHT) for MANETs or Mesh networks, where virtual geographic protocol is used. In previous wort GDHT is applied to a network scenario based on two dimensional Cartesian coordinate system. Further, logical data space is supposed to be uniformly distributed. However, mobile node distribution in a network using virtual geographic routing is not matched to data distribution in GDHT. Therefore, if we apply previous GDHT to a virtual geographic routing network, lots of DHT data are probably located at boundary nodes of the network or specific nodes, resulting in long average-delay to discover resource (or service). Additionally, in BVR(Beacon Vector Routing) or LCR(Logical Coordinate Routing), because there is correlation between coordinate elements, we cannot use normal hash function. For this reason, we propose to use "geographic hash function" for GDHT that matches data distribution to node distribution and considers correlation between coordinate elements. We also show that the proposed scheme improves resource discovery efficiently.

• Journal of KIISE:Databases
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• v.30 no.4
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• pp.420-428
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• 2003

XML is a data-oriented language to represent all types of documents including web documents. By means of the advent of XML-based document generation tools and grow of proprietary XML documents using those tools and translation from legacy data to XML documents at an accelerating pace, we have been gotten a large amount of differently-structured XML documents. Therefore, it is more and more important to retrieve the right documents from the document set. But, previous works on XML have mainly focused on the storage and retrieval methods for a large XML document or XML documents had a same DTD. And, researches that supported the structural difference did not efficiently process path queries on the document set. To resolve the problem, we suggested a new inverted index mechanism using RDBMS and proved it outperformed the previous works. And especially, as it showed the higher efficiency in indirect containment relationship, we argues that the index structure is fit for the differently-structured XML document set.

• Journal of KIISE:Databases
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• v.37 no.4
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• pp.203-208
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• 2010

This paper deals with an efficient index scheduling technique based on Hilbert curve and MBR for k-NN query in a single wireless broadcast channel environment. Previous works have two major problems. One is that they need a long time to process queries due to the back-tracking problem. The other is that they have to download too many spatial data since they can not reduce search space rapidly. Our proposed method broadcasts spatial data based on Hilbert curve order where a distributed index table is also broadcast with each spatial data. Each entry of index table represents the MBR which groups spatial data. By predicting the unknown location of spatial data, our proposed index scheme allows mobile clients to remove unnecessary data and to reduce search space rapidly. As a result, our method gives the decreased tuning time and access latency.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.1
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• pp.27-36
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• 2019

In this paper, we propose a method to find the most similar answer to the user's response from the question-answer database in order to avoid generating a redundant question in retrieval-based automatic question generation system. As a question of the most similar answer to user's response may already be known to the user, the question should be removed from a set of question candidates. A similarity detector calculates a similarity between two answers by utilizing the same words, paraphrases, and sentential meanings. Paraphrases can be acquired by building a phrase table used in a statistical machine translation. A sentential meaning's similarity of two answers is calculated by an attention-based convolutional neural network. We evaluate the accuracy of the similarity detector on an evaluation set with 100 answers, and can get the 71% Mean Reciprocal Rank (MRR) score.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.4
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• pp.624-632
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• 2022

Relationship networks such as an interpersonal relationship network or navigation route search can be expressed in graph form. However, as the amount of data increase, there is a problem that it is difficult to search for the desired data when it is displayed on one screen. In this paper, we propose a visualization method for searching for people, searching for the shortest path between people, and using graphs to express an interpersonal relationship network with many nodes. Unlike the search for the shortest path in the routing table, the shortest path in the interpersonal relationship network should be changeable according to the intension or importance of the researcher or user who is analyzing it. To this end, the BFS algorithm was modified to apply the characteristics of the interpersonal relationship network. For the verification of the results, the data in the character relationship information of the Korean Classics DB in the Korean Classics Translation Institute was used.

• Science of Emotion and Sensibility
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• v.16 no.1
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• pp.53-64
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• 2013

Folksonomies have potential problems caused by synonyms, tagging level, neologisms and so forth when retrieving music by tags. These problems can be tackled by introducing the mood intensity (Arousal and Valence value) of music as its internal tag. That is, if moods of music pieces and their mood tags are all represented internally by numeric values, A (Arousal) value and V (Valence) value, and they are retrieved by these values, then music pieces having similar mood with the mood tag of a query can be retrieved based on the similarity of their AV values though their tags are not exactly matched with the query. As a prerequisite study, in this paper, we propose the mapping table defining the relation between AV values and folksonomy tags. For analysis of the association between AV values and tags, ANOVA tests are performed on the test data collected from the well known music retrieval site last.fm. The results show that the P values for A values and V values are 0.0, which means the null hypotheses could be rejected and the alternative hypotheses could be adopted. Consequently, it is verified that the distribution of AV values depends on folksonomy tags.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12C
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• pp.1217-1224
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• 2003

In this paper, we propose an edge side-lobe suppressor (ESS) for the uplink of OFDMA systems, which mitigates the interference introduced by different frequency offsets between a desired user and the other users. We evaluate the proposed ESS scheme by measuring average signal to interference ratio (SIR) and average bit error rate (BER). The simulation results confirm that the proposed ESS scheme improves system performance by approximately 5∼10 dB SIR as compared to conventional OFDMA systems. Because the additional operations for the proposed scheme can be performed by a real-valued look-up table, the implementation of the ESS hardly requires increasing transmitter and receiver complexity.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.493-498
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• 2008

We proposed "Table Mediator" which is a tabletop system for digital storytelling that uses web-retrieved information for the students' educational field trip. Students can perform their storytelling for their virtual pre-field trip to build up a sequential path as a story with web-retrieved documents, satellite images, geographical information, and group discussion. The proposed system was designed to lessen the limitation of individual interaction such as restricted viewpoint and biased inclination by group digital storytelling. Local interactions also have the limitation such as insufficient information and knowledge and the system supplied the rich live information such as subjective critiques or recently discovered history, or new updates for building a story that makes users arrange their own idea as a consistent story to lessen the limitation of the local interactions. The system can be used for various applications such as travel, education and other collaborative works with group interaction.