• Journal of Korea Spatial Information System Society
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• v.7 no.1 s.13
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• pp.25-37
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• 2005

Recently, with the development of wireless communications and mobile computing, interest about mobile computing is rising. Mobile computing can be regarded as an environment where a user carries mobile devices, such as a PDA or a notebook, and shares resources with a server computer via wireless communications. A mobile database refers to a database which is used in these mobile devices. The mobile database can be used in the fields of insurance business, banking business, medical treatment, and so on. Especially, LBS(Location Based Service) which utilizes location information of users becomes an essential field of mobile computing. In order to support LBS in the mobile environment, there must be an Embedded Spatial MMDBMS(Main-Memory Database Management System) that can efficiently manage large spatial data in spatial mobile devices. Therefore, in this paper, we designed and implemented the Embedded Spatial MMDBMS, extended from the HSQLDB which is an existing MMDBMS for PC, to manage spatial data efficiently in spatial mobile devices. The Embedded Spatial MMDBMS adopted the spatial data model proposed by ISO(International Organization for Standardization), provided the arithmetic coding method that is suitable for spatial data, and supported the efficient spatial index which uses the MBR compression and hashing method suitable for spatial mobile devices. In addition, the system offered the spatial data display capability in low-performance processors of spatial mobile devices and supported the data caching and synchronization capability for performance improvement of spatial data import/export between the Embedded Spatial MMDBMS and the GIS server.

• Journal of Information Technology Services
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• v.10 no.3
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• pp.213-236
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• 2011

Mobile devices are widely accepted as a convenient machine which provides computing capability as well we cell phone capability. Because of limited resources on mobile devices, complex applications could not be deployed on the devices. Service-based mobile applications (SMAs) can provide a solution to overcome the limitation by subscribing cloud services. Since SMAs have complex structures than standalone applications, it is challenging to develop high quality SMAs, to manage both services and mobile applications, and to implement automated billing for subscribed services. Therefore, there is a great demand for a platform for super mobile computing, which supports all key activities in managing life cycle of SMAs. In this paper, we present technical aspects of a platform which is under development; Super Mobile Autonomous Reliable plaTform (SMART). We believe that it provides a number of practical features which are essential in supporting life-cycle of SMAs; development, deployment, management, and operation.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.18 no.2
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• pp.95-102
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• 2012

Background: The purpose of this study was to find out influence of using portable mobile devices in human body. Method: The subjects were consisted of the normal persons (19 males and 20 females). These subjects were consisted of three groups according to test time. The A group (12 persons - 6 males, 6 females) tests 5 minutes, the B group (14 persons - 7 males, 7 females) tests 10 minutes, and the C group (13 persons - 6 males, 7 females) tests 15 minutes. Before test, sight, quickness and balance were measured, after test revision, quickness, balance were measured and checked pain scale. Results: The results were as follows. 1. Sight, quickness and balance were decreased and pains were increased after using portable mobile devices than before using these. 2. According to duration of using the portable mobile devices, sight, quickness and balance was not a statistically significant difference, the entire upper body pain was a statistically significant difference. When viewed as part of the pain, shoulder, lower back, and wrist pain were a statistically significant difference, but the neck and elbow were not a statistically significant difference. 3. The influence of vision according to distance of using Portable mobile devices was no statistically significant difference. In addition, less than 20cm distance using equipment group ("Ga") and the group ("Na") which exceeded 20cm in between the sight were not statistically significant difference, Influence of pain according to distance of using Portable mobile devices we-re no statistically significant differences. Conclusion: Using portable mobile devices affect human body on the elements of the biomechanics.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2001.01a
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• pp.198-201
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• 2001

Recently the wireless-internet has been spreading extensively. People are spending a large part of their time gaining access to information using a mobile device. With the rapid growth of on-line Electronic Commerce, the use of mobile devices creates a new paradigm that provides users with location-independent real time service. Although this new paradigm does have some advantages, limited process speed, low bandwidth, the low battery capacity of mobile devices, and a high rate of wireless network errors causes many overhead expenses during service time with the server. In this paper, we suggest an autonomous service delivery system, which provides mobile agent capability to users that cannot maintain a connection. We have developed the system based on java mobile agent technology. Using this system, we can provide more effective service to users when the user is sending requirements for service through a mobile device that has limited resources. Furthermore we can manage the contact server dynamically when new services are added.

• Journal of Internet Computing and Services
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• v.11 no.2
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• pp.173-184
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• 2010

The advancement of ubiquitous networks facilitates and increases access to the Internet via mobile devices, which offers the advantages of enhanced mobility and accessibility. While Mobile Internet is largely free of temporal and spatial restrictions, producing content for mobile websites is a challenging work due to the existence of multiple device types and markup languages. This paper proposes a technique that makes use of image maps to improve the visual consistency of mobile web content displayed on a variety of mobile devices. The proposed image map method captures several objects comprising the webpage into a single image, and provides the image in Mobile Web services. Mobile devices employing the proposed method can reorganize webpages with multiple objects more easily and obtain the visually identical content on their screen.

• The Journal of the Korea Contents Association
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• v.10 no.8
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• pp.119-129
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• 2010

Recently, development of mobile service and increased demand for mobile device make mobile environment noticeable in computer graphics. Especially demand for 3D graphic services in mobile devices is steadily increased. However up to the present non-photorealistic rendering is mainly studied in desktop platform. In the result, existing research were designed for desktop computers and are not well-suited for mobile devices. Thus, there is a growing needs for processing techniques that provide the ability to render 3D non-photorealistic graphics through mobile devices. In this paper, we discuss processing techniques for non-photorealistic rendering that are especially cartoon shading and rendering in mobile devices. Through the result of this research, it is expected that silhouette edge rendering for mobile display environment and preprocessing file technique for shading. The efficiency of 3D mobile graphic service like 3D model in cartoon style is increased by using proposed preprocessing file and rendering pipeline. Our work can provide mobile cartoon rendering results and various mobile contents to users.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.2
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• pp.484-503
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• 2016

Mobile cloud computing has recently become a new paradigm for the utilization of a variety of shared mobile resources via wireless network environments. However, due to the inherent characteristics of mobile devices, a limited battery life, and a network access requirement, it is necessary for mobile servers to provide a dynamic approach for managing mobile resources efficiently in mobile cloud computing environments. Since on-demand job requests occur frequently and the number of mobile devices is drastically increased in mobile cloud computing environments, a different mobile resource management method is required to maximize the computational power. In this paper, we therefore propose a cooperative, mobile resource sharing method that considers both the inherent properties and the number of mobile devices in mobile cloud environments. The proposed method is composed of four main components: mobile resource monitor, job handler, resource handler, and results consolidator. In contrast with conventional mobile cloud computing, each mobile device under the proposed method can be either a service consumer or a service provider in the cloud. Even though each device is resource-poor when a job is processed independently, the computational power is dramatically increased under the proposed method, as the devices cooperate simultaneously for a job. Therefore, the mobile computing power throughput is dynamically increased, while the computation time for a given job is reduced. We conduct case-based experiments to validate the proposed method, whereby the feasibility of the method for the purpose of cooperative computation is shown.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.33-39
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• 2009

The need for end-to-end security has been increased with the widespread use of mobile devices in wireless internet access applications such as mobile commerce. The WAP1.x has an end-to-end security problem that the message transmitted between the mobile device and the Web server is decrypted inside the gateway within a short time. To overcome this problem, several protocols including WAP2.0 has been proposed. These protocols require that the heavy modules such as TLS or data compression modules should be installed on the mobile device with limited resources. This paper proposes a new WTLSW(WTLS-TLS at Web server) protocol and a new WAP2.0 proxy model in order to ensure end-to-end security between the mobile device and the Web server and to be appropriate for mobile devices with limited resources.

• Journal of Korea Society of Digital Industry and Information Management
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• v.6 no.4
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• pp.75-81
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• 2010

Due to the increasing use of smart phones, using Wifi, Wibro of mobile devices spread. Accordingly, Need of using peer-to-peer file sharing between mobile devices is growing. However, common Peer-to-Peer(P2P) system is too complex and is not suitable to be applied to mobile devices. Thus, the need of research has shown to improve way in a mobile environment that has a constraints as mobility and the scope of communication. Among them, there is a Chord as contents look up algorithm. Chord is the issue. Chord as the DHT-based P2P protocol shares files, index-key and distributed key across the network. However, exist Chord doesn't consider the mobility. So, It has a lot of problems in the mobile environment. Thus, in this paper, I will try to explore an appropriate way of Chord in a mobile environment.

• Korean Journal of Computational Design and Engineering
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• v.12 no.6
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• pp.413-421
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• 2007

3D rendering is becoming a common feature of mobile application programs with the rapid advance of mobile devices. Since the existing rendering engines do not provide triangulation functions, mobile 3D programs have focused on an efficient handling with pre-tessellated geometry. In addition, triangulation is comparatively expensive in computation, so it seems that the triangulation cannot be easily implemented on mobile devices with limited resources. Triangulation of 3D geometry is the essential process of visualization of 3D model data and many different triangulation methods have been reported. We developed a light and fast visualization process that involves constrained triangulation based on Voronoi diagram and applied it to a mobile computer application. In this paper, we applied kd-tree to the original incremental construction algorithm and produced new O(nlogn) incremental construction algorithm. And we show a simple and efficient constrained triangulation method based on Voronoi diagram. This paper also describes an implementation of mobile STEP data viewer as an application of our proposed algorithms.