• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.809-822
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• 2004

In this paper, we propose a concurrency control algorithm based on R-tree for spatial database management system. The previous proposed algorithms can't prevent problem that search operation is to be blocking during update operations. In case of multidimensional indexes like R-tree, locking of update operations may be locked to several nodes, and splitting of nodes have to lock a splitting node for a long time. Therefore search operations have to waiting a long time until update operations unlock. In this paper we propose new algorithms for lock-free search operation. First, we develop a new technique using a linked-list technique on the node. The linked-list enable lock-free search when search operations search a node. Next, we propose a new technique using a version technique. The version technique enable lock-free search on the node that update operations is to be splitting.

• Journal of Digital Convergence
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• v.11 no.7
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• pp.193-199
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• 2013

In this paper, a user search history based potential query recommendation system is proposed to enable the user of information search system to represent one's potential desire for information in terms of query and to facilitate the desired information to be searched. The proposed system has analyzed the association with the existing users's search histories based on the users' search query, and it has extracted the users's potential desire for information. The extracted potential desire for information is represented in terms of recommended query and thereby made recommendations to users. In order to analyze the effectiveness of the system proposed in this paper, we conducted behavioral experiments by using search histories of 27656. As a result of behavioral experiments, the experiment subjects were found to show a statistically significant higher level of satisfaction when using the proposed system as compared to using general search engines.

• Journal of the Korea Safety Management & Science
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• v.8 no.2
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• pp.71-80
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• 2006

There are many display panels in the flight cockpit and pilots get various flight information from those displays. The ergonomic layout of the displays must be determined based upon frequency of use and sequence of use. This study investigated the visual search patterns of the six display groups(one head-up-display: HUD, two multi function displays: MFDs, one engine group: EG, one flight display group: FD and others) in a fighting aircraft. Four expert pilots conducted Imaginary flight in the physical mock-up and the eye movements were collected using eye tracking system. Data of dwell time, frequency of use, and eye movement path were collected. Pilots spent most of time on HUD(55.2%), and others (21.6%), FD(14.2%), right MFD(4.7%), EG(3.2%), and left MFD(1.1%) in descending order. Similarly HUD(42.8%) and others(30.0%) were the most frequently visited displays. These data can be used in the layout of cockpit displays and the determination of optimal visual search pattern.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.3
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• pp.1-10
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• 2012

Recently, Social Network services(SNS) is gaining popularity as Facebook and Twitter. Popularity of SNS leads to active service and social data is to be increased. Thus, social search is remarkable that provide more meaningful information to users. but previous studies using social network structure, network distance is calculated using only familiarity. It is familiar as distance on network, has been demonstrated through several experiments. If taking advantage of social context data that users are using SNS to produce, then familiarity will be helpful to evaluate further. In this paper, reflect user's attention through comments and tags, Facebook context is determined using familiarity between friends in SNS. Facebook context is advantageous finding a friend who has a similar propensity users in context of profiles and interests. As a result, we provide a blog post that interest with a close friend. We also assist in the retrieval facilities using Near Field Communication(NFC) technology. By the experiment, we show the proposed soicial search method is more effective than only tag.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.2
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• pp.92-98
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• 2017

Data clustering determines a group of patterns using similarity measure in a dataset and is one of the most important and difficult technique in data mining. Clustering can be formally considered as a particular kind of NP-hard grouping problem. K-means algorithm which is popular and efficient, is sensitive for initialization and has the possibility to be stuck in local optimum because of hill climbing clustering method. This method is also not computationally feasible in practice, especially for large datasets and large number of clusters. Therefore, we need a robust and efficient clustering algorithm to find the global optimum (not local optimum) especially when much data is collected from many IoT (Internet of Things) devices in these days. The objective of this paper is to propose new Hybrid Simulated Annealing (HSA) which is combined simulated annealing with K-means for non-hierarchical clustering of big data. Simulated annealing (SA) is useful for diversified search in large search space and K-means is useful for converged search in predetermined search space. Our proposed method can balance the intensification and diversification to find the global optimal solution in big data clustering. The performance of HSA is validated using Iris, Wine, Glass, and Vowel UCI machine learning repository datasets comparing to previous studies by experiment and analysis. Our proposed KSAK (K-means+SA+K-means) and SAK (SA+K-means) are better than KSA(K-means+SA), SA, and K-means in our simulations. Our method has significantly improved accuracy and efficiency to find the global optimal data clustering solution for complex, real time, and costly data mining process.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.146-149
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• 2003

As the information that can collect from the web to local database is increasing, we propose a system that can suggest related local documents when new document arrives. We also propose for constructing an association dictionary using web search engines for similarity calculation. The prototype system is also developed, which is described in detail.

• Journal of Digital Convergence
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• v.11 no.2
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• pp.271-277
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• 2013

Typical semantic search query for Semantic search promises to provide more accurate result than present-day keyword matching-based search by using the knowledge base represented logically. Existing keyword-based retrieval system is Preference for the semantic interpretation of a user's query is not the meaning of the user keywords of interconnect, you can not search. In this paper, we propose a method that can provide accurate results to meet the user's search intent to user preference based evaluation by ranking search. The proposed scheme is Integrated ontology-based knowledge base built on the formal structure of the semantic interpretation process based on ontology knowledge base system.

• Journal of Information Processing Systems
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• v.7 no.3
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• pp.447-458
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• 2011

This study presents a comprehensive solution to the collection management, which is based on the model for Cultural Objects (CCO). The developed system manages and spreads the collections that are safeguarded in museums and galleries more easily by using IT. In particular, we present our approach for a non-structured search and recovery of the objects based on the annotation of artwork images. In this methodology, we have introduced a faceted search used as a framework for multi-classification and for exploring/browsing complex information bases in a guided, yet unconstrained way, through a visual interface.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.2
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• pp.55-66
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• 2015

In this paper, we design and implement a two-way search algorithm that can provide a customized service through the user with real-time two-way communication using a mobile instant messaging service. Therefore, we design and implement the automative search system which enables delivering message to each user mobile terminal from a plurality of relay mobile terminals by utilizing the mobile instant messenger, not to deliver a message from the main server to the mobile instant messenger user directly. Two-way search system using the mobile instant messenger can be immediately collect the user's response is easy to identify the orientation of each user, and thus can be provided to establish a differentiated service plan. Also, It provides a number of services(text, photos, videos, etc) in real-time information to the user by utilizing the mobile instant messenger service without the need to install a separate application. Experiment results, data processing speed of the category processing way to search for the data of the DB server from a user mobile terminal is about 7.06sec, data processing number per minute is about 13 times. The data processing speed of the instruction processing way is about 3.10sec, data processing number per minute is about 10 times. The data processing speed of the natural language processing way is about 5.13sec, per data processing number per minute is about 7 times. Therefore in category processing way, command processing way and natural language processing way, instruction processing way is the most excellent in aspect of data processing speed, otherwise in aspect of per data processing number per minute, the category processing way is the best method.

• Journal of the Korean Society for information Management
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• v.24 no.2
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• pp.29-44
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• 2007

The purpose of this study was to explore whether the concept of amount of invested mental effort (AIME) developed in the field of educational psychology can help explain why people put so little effort into online searching. In this experimental study, two information retrieval systems - a web search engine and a university library system - were used to make a comparison. The data were collected from 15 undergraduate students through background questionnaires, think-aloud protocols, search logs, post-search questionnaires, and post-task interviews. The findings indicate that perception of the web's "easy-ness" and high levels of self confidence in searching capability led the subjects to put less effort into web searching than they do into library system searching. In addition, the perceived difficulty of search task influenced the extent of mental effort invested. The AIME proved a useful framework for understanding search behavior and user experience for both web search engines and library systems.