• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.1051-1052
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• 2008

As the mobile phone has multi functions and high performance, multimedia processors have an important roles in handsets. Recently high resolution camera (above 5M pixels), HD Camcording and beautiful UI which Using OpenVG or OpenGL are adopted in mobile phone. So we are introduced the function multimedia processor and guide to mobile phone engineers to meet multimedia features.

• Journal of Information Technology Applications and Management
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• v.14 no.3
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• pp.169-178
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• 2007

The next generation mobile multimedia network is expected to provide higher-rate multimedia communication services to versatile mobile terminals moving in even higher speed. For achieving more efficient reusability of scarce radio resources and thereby accommodating more user population in this network, the smaller cell such as micro or pico cell structure is used. More efficient and faster hand-over schemes are necessary to prevent the degradation of QoS of multimedia services caused by hand-over processing delay and packet loss during frequent hand-over. This paper proposes a faster and more effective hand-over scheme for high-rate multimedia services in the future mobile multimedia networks. by utilizing the GPS information on the position of the mobile terminal and its estimated moving directions. The simulation results show that our proposed method provides a better performance than the conventional method.

• Journal of Digital Contents Society
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• v.14 no.3
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• pp.357-365
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• 2013

The popularization of smart phones changes the usage patterns of mobile communication from voice-centric to data-centric communication. The demand for wireless data communications is rapidly increasing, and thus the need for expanding infrastructure for mobile communication is also rapidly increasing. In this paper, we propose a scheme for reducing the cost for the mobile communication infrastructure by exploiting opportunistic networks in dissemination of multimedia contents. By using this scheme, the large portion of the cost for mobile communication infrastructure could be saved, and the need of users for multimedia contents could be also fulfilled. Our scheme is evaluated using agent-based simulations. The simulation results show that about 70% of mobile communication can be replaced with the data communication through opportunistic networks.

• Journal of Korea Multimedia Society
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• v.5 no.6
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• pp.704-711
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• 2002

Multimedia communication systems are characterized by supporting three different typer of services such as circuit switched services, and packet switched real Lime and non real time services. The wireless channels in a cell ate allocated by calls of these different service classes and the different service requirements have to be met. SRN is an extension of stochastic Petri nets and provides compact Modeling facilities for system analysis. To get the performance index, appropriate reward rates are assigned to its SRN. In this paper, we present a SRN model for performance analysis of channel allocation of multimedia mobile communication systems. The key contribution of this paper constitutes the Petri nets modeling techniques instead of complicate numerical analysis of Markov chains and easy way of performance analysis for channel allocations under SRN rewards concepts.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.231-233
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• 2005

For the low-power design of the mobile multimedia system architecture, this paper modeling the mobile multimedia system and analysis the power consumption profile about the whole communication environment. The mobile system model consist of air interface, RIP front-end, base-band processing module and human interface. For the result of power consumption profile analysis, the power consumption of multimedia processing is above 60% compare to the whole power consumption in mobile multimedia system. To minimize the power consumption in processing module which consumes the large power, this paper proposed the Microscopic DVS technique which applies the optimum voltage for the each multimedia frame. For the simulation result, proposed power minimization technique reduce the power consumption about 30%.

• Journal of Advanced Navigation Technology
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• v.17 no.1
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• pp.56-62
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• 2013

Recently with smart phones and tablets, next generation mobile communication systems have supported various multimedia contents services. Thus, multimedia communication systems have been gradually increased compared to voice communication systems. Since the growth of multimedia services has increased users' duration on systems and decreased systems' effectiveness on power, a study on effective usage of power needs to be researched. Furthermore, radio shadow areas under heavy urban environments have generated unnecessary power consumption which reduces the usage duration of power on next generation mobile communication systems. This paper has reviewed the communication network architecture on next generation mobile communication systems and the unnecessary power consumption in radio shadow areas. This paper has also proposed the method of the effective power usage and analyzed the effective power usage on next generation mobile communication systems with simulation.

• Journal of Korea Multimedia Society
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• v.6 no.3
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• pp.518-526
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• 2003

According to the development of mobile communications, the future mobile communication systems are expected to provide high quality multimedia service to users. Therefore, many technical factors we needed in these systems. Especially the confidentiality and the security would be obtained through the introduction of the security for mobile communications. In this paper, we propose an efficient Proxy-Signcryption scheme, which can be performed digital signature and encryption by using the proxy agent who has more computational power under mobile communications environment. The proposed scheme provides non-repudiation and prevents creating illegal signature by the origin and proxy agent in a phase of proxy signature processing. This scheme also keeps the confidentiality and the security in mobile communication by means of confirming the signature by right receiver.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.883-890
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• 2008

It becomes enabled to provide variety of multimedia contents through mobile service with the development of high-speed 3rd generation mobile communication and handsets. MMS (Multimedia Messaging Service) can be displayed in the presentation format which is unified the various multimedia contents such as text, audio, image, video, etc. It is applicable as a new type of ubiquitous learning. In this study we propose to design a mobile learning system by providing profiles which meets the standard of CC/PP and by generating multimedia messages based on SMIL language through the adaptation steps according to the learning environment, the content type, and the device property of learners.

• Journal of Korea Multimedia Society
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• v.18 no.10
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• pp.1225-1230
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• 2015

Mobile Sensor Networks (MSN) is composed of a distributed collection of mobile sensor nodes, each of which has sensing, computation, communication and locomotion capabilities. Since the routing path can be broken when some nodes on the path move to other position, MSN may have a high rate of communication failure. So, MSN has to provide a means for low-cost and low-power routing to support mobility of sensor nodes. In this paper, a limited flooding scheme for routing in MSN is proposed to allow efficient energy utilization without requiring any complicated tasks for path maintenance.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.27-36
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• 2020

The popularization of smartphones allows people to instantly get the information that they want, through mobile apps, including financial services, movies and public transportation reservations, games and shopping. Furthermore, leisure activities through overseas travel are increasing due to the improvement of the living standards of people. These increases in overseas travel and the use of mobile apps lead to the increased use of mobile travel apps when booking tour packages. Although there are many studies on the usability assessment and user interface improvement for mobile apps, studies on the usability assessment for mobile travel apps are limited. We tested the usability for mobile travel apps to present some suggestions for improvements so that anyone can purchase travel packages easily and simply. We selected the top three mobile travel apps on Rankey.com that have different UIs. The heuristic method was used to evaluate usability. We present a better UI to allow users to use the app functions more easily by analyzing user interaction, ease of learning, readability, efficiency, and satisfaction for the entire use.