• Journal of the Korea Society of Computer and Information
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• v.23 no.2
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• pp.35-43
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• 2018

In this paper, we propose a grid-based efficient routing protocol for a mobile sink in wireless sensor networks. In the proposed protocol, the network is partitioned into grids and each grid has a grid head. For the efficient routing to a mobile sink, the proposed protocol uses a mobile sink representative node to send the data to a mobile sink and grid heads are used as a mobile sink representative node. Furthermore, the proposed protocol uses nodes in the boundary of the center grid as position storage nodes. The position storage nodes store the position of a mobile sink representative node and provide source nodes with it for data delivery. With these features, the proposed protocol can reduce a lot of overhead to update the position information and improve the delay of data delivery to a mobile sink. The proposed protocol performs better than other protocols in terms of the delay and the energy consumption per node in the performance evaluation.

• Journal of Korean Society of Rural Planning
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• v.20 no.4
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• pp.277-284
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• 2014

Recently the use of smart phones and mobile devices is increasing rapidly, data search and retrieval in the mobile environments are generalized. There are only few mobile applications available in the area of agriculture while huge amount of new applications are developed and uploaded. The purpose of this study was to develop the android based mobile application for providing agricultural infrastructure and disaster information. The mobile application was designed through the database establishment and management system, server management system, and mobile application development. The database is composed of weather data, agricultural infrastructure data, and agricultural disaster data. By developing the mobile application which provides agricultural infrastructure information, it is expected to improve the accessibility to agricultural information and mitigate the agricultural disaster damages.

• Journal of Korea Society of Digital Industry and Information Management
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• v.8 no.1
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• pp.99-105
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• 2012

Given the numbers of smartphones, tablets and other mobile devices shipped every day, more and more users are relying on the cloud as the main driver for satisfying their computing needs, whether it is data storage, applications or infrastructure. Mobile cloud computing is simply cloud computing in which at least some of the devices involved are mobile. Each node is owned by a different user and is likely to be mobile. Using mobile hardware for cloud computing has advantages over using traditional hardware. These advantage include computational access to multimedia and sensor data without the need for large network transfer, more efficient access to data stored on other mobile devices and distributed ownership and maintenance of hardware. It is important to predict job execution time in mobile cloud computing because there are many mobile nodes with different capabilities. This paper analyzes the job execution time for mobile cloud computing in terms of network environment and heterogeneous mobile nodes using a mathematical model.

• 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 Korea Multimedia Society
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• v.7 no.5
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• pp.689-697
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• 2004

Rapid advances in mobile computing and the availability of wireless communications will soon provide mobile users with the ability to access data regardless of the location of the user or of the data. SRA(Static Replica Allocation) that is traditional scheme has been used for the replication method on the server. This replicates the data on the replica server after a moving host has been transferred to the cell. This strategy is simple and can easily relocate data. However, if a mobile user does not exist in the cell, the replicated data can be deleted in order to maintain data consistency. In addition to, if the mobile host leaves from replicated cell, it is difficult to access data in terms of replication route. Therefore, this paper proposes a new method of relocation based on data consistency strategy called USRAC(User Selection Replica Allocation based on Consistency) and also analyzes access cost according to the moving rate of mobile users, according to the access rate of mobile hosts, and according to the number of cells of mobile users and mobile hosts.

• Proceedings of the KSRS Conference
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• 2005.10a
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• pp.705-708
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• 2005

Mobile Mapping Systems using the vehicle equipped the GPS, IMU, CCD Cameras is the effective system for the management of the road facilities, update of the digital map, and etc. They must provide users with the sensor data which is acquired by Mobile Mapping Systems in real-time so that users can process what they want by using the latest data. But it' s not an easy process because the amount of sensor data is very large, particularly image data to be transmitted. So it is necessary to reduce the amount of image data so that it is transmitted effectively. In this study, the effective method was suggested for the compression/decompression image data using the Wavelet Transformation and Huffman Coding. This technique will be possible to transmit of the geographic information effectively such as position data, attitude data, and image data acquired by Mobile Mapping Systems in the wireless internet environment when data is transmitted in real-time.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.11-19
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• 2015

Due to recent development in mobile devices, the mobile device utilization and many related applications have been increasing. Most of initial applications on mobile devices just showed simple information, but now they processes huge data. However, smart devices have certain limitations in processing massive data. Especially, if the size of data increases, the speed of data processing adversely decreases, so the performance of programs also decreases. If hardware specification of the mobile devices is not enough to handle it, response time will be drastically delayed. To overcome these drawbacks, most of application running on mobile devices communicate with their servers to manage data. XML is a proper language for data communication to send and receive data between servers and mobile devices, because it defines rules of document's format and it is a textual data format and small-sized language. However, mobile devices have limitation such as memory, CPU and wireless network to process huge data and XML also takes a lot of time to communicate with servers and devices and handle data, so it could be overhead in service time. Binary XML is an alternative of performance improvement in data processing, which has XML's benefits and minimizes the XML size by binary coding. However, most of binaryXML which are used on applications don't fit on mobile applications. In this paper, we surveyed many kinds of binaryXML, compared merits and demerits to find a binaryXML for mobile applications. We propose how to use binary XML and implemented an electronic attendance system using binary XML to overcome the limitation of XML and to reduce the load of data communications between servers and devices.

• Journal of Information Technology Services
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• v.10 no.4
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• pp.269-280
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• 2011

Mobile Augmented Reality (mobile AR), as one of the most prospective mobile applications, intends to provide richer experiences by annotating tags or virtual objects over the scene observed through camera embedded in a handheld device like smartphone or pad. In this paper, we analyzed the current status of the art of mobile AR and proposed a novel Points of Interest (POIs) data model based on ontology to provide context-aware information retrievals on lots of POIs data. Proposed ontology was expanded from the standard POIs data model of W3C POIs Working Group and established using OWL (Web Ontology Language) and Protege. We also proposed a context-aware mobile AR platform which can resolve three distinguished issues in current platforms : interoperability problem of POI tags, POIs data retrieval issue, and context-aware service issue.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.481-484
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• 2003

For map services in the mobile environment, it should be considered that resource restriction of the mobile device. Thus, if a map database dedicated to mobile services may not be developed, the spatial data extracted from general map databases should be simplified before transmitting. This paper suggests the mechanism to simplify and modify the spatial data, which are changed to be able to displayed on the mobile devices. This mechanism is based on the map generalization operations and is refined to adapt on mobile phone environment.

• Journal of KIISE:Databases
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• v.32 no.4
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• pp.394-404
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• 2005

Battery capacity of mobile clients in wireless mobile computing environments is one of the important resources that determine the availability of mobile clients. So, data broadcast techniques in mobile computing environments need not only rapid delivery of requested data but also efficient data delivery mechanisms which can reduce battery consumption of mobile clients. This paper proposes organization of an index and broadcast data for on-demand data broadcast. It organizes an index containing broadcast time of each data using some of high-priority data in a broadcast server. By sending such index information prior to the corresponding data, the proposed approach reduces tuning time of mobile clients. It also includes when the next index information will be broadcasted in each data broadcast. This can reduce tuning time of mobile clients waiting for an index to be broadcasted. Experiments show that the proposed approach effectively reduces tuning time of mobile clients.