• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.10
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• pp.2529-2547
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• 2012

In this paper, we use a quadrotor-based mobile sink to gather sensor data from the terrestrial deployed wireless sensor network. By analyzing the flight features of the mobile sink node, we theoretically study the flight constraints of height, velocity, and trajectory of the mobile sink node so as to communicate with the terrestrial wireless sensor network. Moreover, we analyze the data amount which the mobile sink can send when it satisfies these flight constraints. Based on these analysis results, we propose a data acquisition approach for the mobile sink node, which is discussed detailed in terms of network performance such as the transmission delay, packet loss rate, sojourning time and mobile trajectory when given the flying speed and height of the mobile sink node. Extensive simulation results validate the efficiency of the proposed scheme.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.4
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• pp.357-367
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• 2005

According to the recent advancement of mobile computing technology and the hardware technology, the mobile device has rapidly come into wide use.'rho data in the central management server needs to confirm to that in mobile devices in order for the mobile device users to access the needed data regardless of time and place. This is called Data Synchronization. Currently, major mobile device manufacturing companies provide the data synchronization solutions, but these solutions are not compatible with other mobile devices/other applied services. In order to solve this problem, OMA(Open Mobile Alliance), mainly composed of mobile telecommunication companies, has suggested using the SyncML(Synchronization Markup Language) data synchronization method. This is an attempt to make a public standard. In this paper, the data synchronization client that synchronizes the PIMS (Personal Information Management System) data in mobile devices like PDA is developed, complying with the SyncML standard requirements.

• Journal of Internet Computing and Services
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• v.7 no.3
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• pp.61-69
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• 2006

Data synchronization between data stored in mobile communication terminals and a central server is one of essential tasks for efficient mobile communication environments. Since, however, manufacturers of mobile terminals have their proprietary data synchronization mechanisms, data interoperability can hardly be achieved. Therefore, SyncML data synchronization mechanism in mobile communication environments was proposed as an open standard by OMA(Open Mobile Alliance). In this paper, a SyncML-based data synchronization gateway is designed and implemented which can process ActiveSync data also. In other words, by constructing a combined data synchronization gateway which can transform ActiveSync data into SyncML data, data interoperability between mobile terminals which use two different data synchronization mechanisms can be achieved, In addition, mobile communication experiments between ActiveSync-based terminals and a SyncML-based central server show that the data synchronization gateway constructed in this paper, works correctly.

• International journal of advanced smart convergence
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• v.10 no.4
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• pp.52-58
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• 2021

Data access bias can be observed in various types of computing systems. In this paper, we characterize the data access bias in modern mobile computing platforms. In particular, we focus on the access bias of data observed at three different subsystems based on our experiences. First, we show the access bias of file data in mobile platforms. Second, we show the access bias of memory data in mobile platforms. Third, we show the access bias of web data and web servers. We expect that the characterization study in this paper will be helpful in the efficient management of mobile computing systems.

• Journal of Information Processing Systems
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• v.16 no.4
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• pp.743-749
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• 2020

Internet of Things (IoT) is a growing technology along with artificial intelligence (AI) technology. Recently, increasing cases of developing knowledge services using information collected from sensor data have been reported. Communication is required to connect the IoT and AI, and 5G mobile networks have been widely spread recently. IoT, AI services, and 5G mobile networks can be configured and used as sensor-mobile edge-server. The sensor does not send data directly to the server. Instead, the sensor sends data to the mobile edge for quick processing. Subsequently, mobile edge enables the immediate processing of data based on AI technology or by sending data to the server for processing. 5G mobile network technology is used for this data transmission. Therefore, this study examines the challenges, opportunities, and solutions used in each type of technology. To this end, this study addresses clustering, Hyperledger Fabric, data, security, machine vision, convolutional neural network, IoT technology, and resource management of 5G mobile networks.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.838-843
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• 2002

Recently, PDA and cellular phone with color LCD have been widely used in various fields by high efficiency and micro miniaturization technology. According to maturity of these mobile environments, user request about mobile application field is increased. Mobile applications provide various information which is concerned with user's position through cable and wireless transmission. This paper discusses the issues related to the mobile framework for integrated 4S data. The integrated 4S data mean spatial data fusion on GIS, SIIS, ITS, and GNSS. The mobile framework provides not only spatial data but also location services such as reverse geocoding, directory service, etc. It consists of client subsystem, service provider, and data provider.

• ETRI Journal
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• v.43 no.3
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• pp.427-435
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• 2021

Data filtering is an essential task for improving the energy efficiency of radiofrequency identification (RFID) networks. Among various energy-efficient approaches, clustering-based data filtering is considered to be the most effective solution because data from cluster members can be filtered at cluster heads before being sent to base stations. However, this approach quickly depletes the energy of cluster heads. Furthermore, most previous studies have assumed that readers are fixed and interrogate mobile tags in a workspace. However, there are several applications in which readers are mobile and interrogate fixed tags in a specific area. This article proposes a model for dynamic clustering-based data filtering (DCDF) in mobile RFID networks, where mobile readers are re-clustered periodically and the cluster head role is rotated among the members of each cluster. Simulation results show that DCDF is effective in terms of balancing energy consumption among readers and prolonging the lifetime of the mobile RFID networks.

• Journal of Internet Computing and Services
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• v.22 no.5
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• pp.9-16
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• 2021

Recently, the traffic volume of mobile communications increases rapidly and the small-cell is one of the solutions using two offload schemes, i.e., local IP access (LIPA) and selected IP traffic offload (SIPTO), to reduce the end-to-end delay and amount of mobile data traffic in the core network (CN). However, 3GPP describes the concept of LIPA and SIPTO and there is no decision algorithm to decide the path from source nodes (SNs) to destination nodes (DNs). Therefore, this paper proposes a dynamic mobile data traffic offload scheme using small-cells to decide the path based on the SN and DN, i.e., macro user equipment, small-cell user equipment (SUE), and multimedia server, and type of the mobile data traffic for the real-time and non-real-time. Through analytical models, it is shown that the proposed offload scheme outperforms the conventional small-cell network in terms of the delay of end-to-end mobile data communications and probability of the mobile data traffic in the CN for the heterogeneous networks.

• Journal of information and communication convergence engineering
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• v.7 no.1
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• pp.41-45
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• 2009

In mobile GIS environments, a client needs to receive the isogram data with a topographical map from a server, if the mobile client wants to display map with elevation information. Because the elevation data size is normally quite large, the client will suffer some problems to receive the elevation data from server. The main reason is a resource limitation of the mobile devices. To overcome these problems, this paper proposes new data structures and algorithms. They are designed for efficient transmission of contour data to a client. Because of the contour data are generated as a vector style from elevation information stored at a server, the proposed algorithms are focused to minimize the transmission data volume and time.

• Journal of the Korean Data and Information Science Society
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• v.18 no.4
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• pp.1157-1170
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• 2007

LBS must manage various context data and make the best use of this data for application service in ubiquitous environment. Conventional mobile object data management architecture did not consider process of context data. Therefore a new mobile data management framework is needed to process location context data. In this paper, we design a new context management framework for a location based application service. A suggestion framework is consisted of context collector, context manager, rule base, inference engine, and mobile object context database. It describes a form of rule base and a movement process of inference engine that are based on location based application scenario. It also presents an embodiment instance of interface which suggested framework is applied to location context interference of mobile object.