• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.263-266
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• 2013

The universal cloud computing environment, the increase of mobile devices, and the emergence of various web-based services require large amounts of storage space. With the widespread use of Web-based storage services, such as Google Drive, Naver Ndrive, Daum Cloud, there is a need for more storage space. Therefore, storage areas can be provided according to the needs of users of virtualized storage resources through a network, and a large, easy to extend, and royalty in a specific geographical location, cloud storage may be the limelight. In this paper, find out about the features of open source software technology, Hadoop, Swift, GlusterFS for Cloud Storage infrastructure.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.9
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• pp.615-620
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• 2013

With the development of smartphones, the number of applications for smartphone increases sharply. As a result, users need to try several times to find their favorite apps. In order to solve this problem, we propose a recommendation system to provide an appropriate app list based on the user's log information including time stamp, location, application list, and so on. The proposed approach learns three recommendation models including Naive-Bayesian model, SVM model, and Most-Frequent Usage model using temporal and spatial attributes. In order to figure out the best model, we compared the performance of these models with variant features, and suggest an hybrid method to improve the performance of single models.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.3
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• pp.141-148
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• 2017

The current advancement of mobile devices enables users to collect a sequence of user positions by use of the positioning technology and thus the related research regarding positioning or location information are quite arising. An individual mobility model based on positioning data and time data are already established while group mobility model is not done yet. In this research, group mobility model, an extension of individual mobility model, and the process of establishment of group mobility model will be studied. Based on the previous research of group mobility model from two individual mobility model, a group mobility model with more than two individual model has been established and the transition pattern of the model is represented by Markov chain. In consideration of real application, the computing time to establish group mobility mode from huge positioning data has been drastically improved by use of GPGPU comparing to the use of traditional multicore systems.

• Smart Media Journal
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• v.5 no.4
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• pp.26-40
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• 2016

Recent researches have been conducted for a user of the position acquisition and analysis since the mobile devices was developed. Trajectory data mining of location analysis method for a user is used to extract the meaningful information based on the user's trajectory. It should be preceded by a process of extracting Stay Point. In order to carry out trajectory data mining by analyzing the user of the GPS Trajectory. The conventional Stay Point extraction algorithm is low confidence because the user to arbitrarily set the threshold values. It does not distinguish between staying indoors and outdoors. Thus, the ambiguity of the position is increased. In this paper we proposed extraction method of Stay Point using a statistical analysis. We proposed algorithm improves position accuracy by extracting the points that are staying indoors and outdoors using Gaussian distribution. And we also improve reliability of the algorithm since that does not use arbitrarily set threshold.

• Smart Media Journal
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• v.5 no.4
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• pp.90-95
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• 2016

Recently, the quality of cultural experience can be improved through a stereoscopic information service provided by the latest mobile-based Information Telecommunication technology without the human cultural commentators, which was used in order to enhance the understanding of our cultural heritage. The purpose of this paper is to produce contents that introduce cultural heritage using the Android-based GPS and augmented reality. In this paper we propose a culture content creation method that is based on location information such as user/cultural anomalies using GPS and augmented reality based on Markerless Tracking. Marker Detection Technology and Markerless Tracking Technology are used for smart phone's rapid recognition of augmented real world and accurate recognition according to the state of the cultural heritage. Also, the Google Map of Android is used to locate the user. The strength of this method lies in that it can be used for a variety of subjects while the existing methods are limited to certain kinds of augmented reality contents.

• The Journal of the Korea Contents Association
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• v.6 no.1
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• pp.114-125
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• 2006

Since wireless Internet services and small mobile communication devices come into wide use as well as the use of GPS is rapidly growing, researches on moving object, whose location information shifts sequently in accordance with time interval, are being carried out actively. Especially, the researches on vehicle moving object are applied to Advanced traveler information system, vehicle tracking system, and distribution transport system. These systems are very useful in searching previous positions, predicted future positions, the optimum course, and the shortest course of a vehicle by managing historical data of the vehicle movement. In addition, vehicle historical data are used for distribution transport plan and vehicle allocation. Vehicle historical data are stored at regular intervals, which can have a pattern. For example, a vehicle going repeatedly around a specific section follows a route very similar to another. If historical data of the vehicle with a repeated route course are stored at regular intervals, many redundant data occur, which result in much waste of storage. Therefore this thesis suggest a vehicle historical data store scheme for vehicles with a repeated route course using similar trajectory which efficiently store vehicle historical data.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.12
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• pp.2272-2293
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• 2011

Communication technology of future networks is predicted to provide a large variety of services including WiFi service in vehicular network. In this paper, we assume that vehicles are embedded with WiMAX antenna and in-vehicle terminals receive WiMAX traffic through WiFi interface. This assumption will impose severe performance degradation due to interference among mobile BSSs when WiFi access points (APs) are densely located. Existing interference avoidance techniques cannot properly resolve the above problems and do not cope with dynamically moving vehicular scenario since they focus only on the fixed network topology. In this paper, we propose a mobility-aware interference avoidance scheme for WiFi services. The proposed scheme computes the interference duration by exploiting mobility vector and location information of neighboring APs. If the interference duration is not negligible, our scheme searches for another channel in order to avoid interference. However, if the interference duration is negligible, our scheme continues to use the channel to reduce switching overhead. To measure the effectiveness of the proposed scheme against other existing techniques, we evaluated performance by using OPNET simulator. Through the simulation, we obtained about 60% reduction in the maximum interference frequency and about 67% improvement in throughput. Furthermore, our scheme provides fair channel usage.

• Journal of Korea Spatial Information System Society
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• v.12 no.1
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• pp.95-99
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• 2010

Spatial information systems have developed in order to provide users with customized land information in u-City environments. The spatial information systems can detect spatial information for users anytime anywhere. Information which is analyzed by data mining techniques can be offered for other users. Therefore, we propose open map API-based prototype which utilizes frequent pattern mining technique. Proposed prototype can mine interesting trip routes and unknown attractions in location data of geophoto. Also, proposed prototype is the first attempt which analyzes spatial patterns can be represented on a map which is selected by users. Our prototype can be applied to the smart phone like mobile devices.

• Journal of Internet Computing and Services
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• v.12 no.1
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• pp.11-25
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• 2011

In ubiquitous computing environment, OSGi has applied to many areas such as digital mobile phones, vehicles, telematics, embedded appliances, residential gateways, industrial computers, desktop PCs, and high-end servers including mainframes. Therefore, interoperability is required for remote OSGi services which are built on various devices. In this paper, we proposed a method which was able to interoperate remote OSGi services using RMI paradigm. RMI is a representative middleware technology in distributed computing environment. The suggested method is based on the standard OSGi technology. It is possible to provide remote OSGi service registration, finding, and binding methods which were suitable for the OSGi service-oriented architecture. We also provided reliability of the dynamic remote OSGi services by maintaining consistent properties of them, and we could provide location transparency of the remote OSGi services by generating proxy bundles and proxy services dynamically.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.4 no.5
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• pp.939-955
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• 2010

With the progress of IT and mobile positioning technologies, various types of location-based services (LBS) have been proposed and implemented. Finding a shortest path between two nodes is one of the most fundamental tasks in many LBS related applications. So far, there have been many research efforts on the shortest path finding problem. For instance, $A^*$ algorithm estimates neighboring nodes using a heuristic function and selects minimum cost node as the closest one to the destination. Pruning method, which is known to outperform the A* algorithm, improves its routing performance by avoiding unnecessary exploration in the search space. For pruning, shortest paths for all node pairs in a map need to be pre-computed, from which a shortest path container is generated for each edge. The container for an edge consists of all the destination nodes whose shortest path passes through the edge and possibly some unnecessary nodes. These containers are used during routing to prune unnecessary node visits. However, this method shows poor performance as the number of unnecessary nodes included in the container increases. In this paper, we focus on this problem and propose a new border line-based pruning scheme for path routing which can reduce the number of unnecessary node visits significantly. Through extensive experiments on randomly-generated, various complexity of maps, we empirically find out optimal number of border lines for clipping containers and compare its performance with other methods.