• Journal of the Korea Society of Computer and Information
• /
• v.14 no.7
• /
• pp.123-132
• /
• 2009

The perforrnance and portability of mobile applications can be greatly increased by adopting proxy modiles which exists between the conventional system and the device. When mobile devices collaborate with the conventional computers, there are problems to address: a battery life problem, limited input and output methods, and intermittent wireless connection. Those issues are magnified in the multimedia collaboration environment since it works in a real-time condition and the size of the message in the system is big in many cases. Additionally, because multimedia collaboration system softwares are too heavy and complex for mobile devices, it is veη hard to integrate them with conventional systems. In this paper, we describe our design and its implementation of a novel approach to map events (i.e. messages) using a proxy for mobile applications. We adopt a proxy to provide a content adaptation (i.e. transcoding) where the message contents are customized. Also, we design a mobile version publish/subscribe system to provide communication service for mobile device in loosely coupled and flexible manner. We present our empirical results which show that our design can be efficiently implemented and integrated with a conventional multimedia collaboration system.

• Journal of the Semiconductor & Display Technology
• /
• v.19 no.1
• /
• pp.23-28
• /
• 2020

In Smart mobile devices embedding big.LITTLE architectures, the conventional multi-core assignment scheme for user applications may incur wasteful energy consumption and long response time. In this paper, we propose a user experience assisted energy-efficient multicore assignment scheme. Our simulation results show that the proposed scheme achieves at 40% less energy consumption and at 20% less response time comparing to the legacy scheme.

• Journal of Korea Multimedia Society
• /
• v.15 no.10
• /
• pp.1212-1220
• /
• 2012

In this paper, a collision-free resource reservation scheme for WUSB (Wireless Universal Serial Bus) networks with WiMedia D-MAC (Distributed Medium Access Control). Since distributed characteristic of the WiMedia D-MAC supporting DRP (Distributed Reservation Protocol) scheme may cause lots of conflicts, overall performances of the WUSB with WiMedia D-MAC can be deteriorated. In addition, when we consider multi-hop environment, "mobile" hidden node problem due to mobility of WUSB devices can be happened, and it is a critical problem to mobile WUSB devices transceiving real-time QoS (Quality of Service) traffic. To tackle the problem, we propose a new DRP reservation mechanism to prevent DRP conflicts for multi-hop mobility support in WUSB networks with WiMedia D-MAC and show its improved performance via simulation results.

• Journal of Korea Multimedia Society
• /
• v.10 no.3
• /
• pp.373-380
• /
• 2007

In this paper we propose a new efficient authentication protocol that reduces overheads of computation for digital signature generation/verification on mobile devices in the Personal Area Network (PAN). In particular, we focus on eliminating the traditional public key operations on mobile devices without any assistance of a signature server. Moreover, the proposed protocol provides a simplified procedure for certificate status management to alleviate communication and computational costs on mobile devices in the PAN.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.1B
• /
• pp.9-18
• /
• 2006

Advances in wireless network are enabling the development of ubiquitous multimedia services. These multimedia services need efficient platforms to comply with the requirements of mobile computing. We introduce an adaptive service platform based on mobile agent and grid systems while specifying the challenges of ubiquitous multimedia services and focusing on frequent disconnections and scarce resources. We applied our platform to framework RtoA (Ready-to-Attend) which supports mobile users to access compute-intensive multimedia service, specifically, mobile education and video conferencing. RtoA includes hand-off, speaker and listener service which enable people to attend a conference or a class with satisfying quality of multimedia service. ns-2 based simulation verifies that our scheme is an efficient way to reduce energy consumption of mobile devices and to improve the response time of mobile applications.

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

• Proceedings of the Korea Multimedia Society Conference
• /
• 2012.05a
• /
• pp.83-85
• /
• 2012

Gait analysis through wearable sensors is becoming a key research topic in mobile. In gait analysis, step detection is one of the most important processes that will lay down the foundation for future implementation. In this paper, we will propose a simpler algorithm to determine and analyze the steps using accelerometer sensor built-in mobile phone that physically placed into the trouser pocket. This is the location where most of mobile devices are. With 5 volunteers walking in 160 seconds, the accuracy of this method is approximately 98.5%.

• Annual Conference of KIPS
• /
• 2011.04a
• /
• pp.378-381
• /
• 2011

These days rapid improvement in Mobile phones and their multimedia limits made them powerful enough to manage complicated tasks. Image processing related support for mobile devices is extremely comprehensive in wireless telemedicine. A basic challenge is how to get best quality of image with the limited screen size and resources of mobile phones. This paper deals with image processing features (capturing rendering and zooming in and out) of Mobile Media API and Advanced Multimedia Supplements (MMAPI and AMS) developed for Mobile Java Platform and customized algorithm is designed to keep all image task cost efficient by using minimum device resources and memory. This scenario is driven by the need for evaluation of a distant patient that cannot be moved to the expert.

• Journal of Korea Multimedia Society
• /
• v.18 no.2
• /
• pp.178-188
• /
• 2015

The proliferation of devices such as tablets and smart phones, which are now used by many people in their daily lives, has led to a number of companies allowing employees to bring their own devices to work due to perceived productivity gains and cost savings. However, despite many advantage, security breaches (e.g., information leakage) can happen for various reasons (e.g., loss or theft of devices, and malicious code) and privacy breaches can happen by using personal devices for business. We should carefully scrutinize security threats in this area. We present the security threats analysis and the technical approach in this area, and discuss privacy threats and countermeasures.

• Journal of Korea Multimedia Society
• /
• v.11 no.8
• /
• pp.1179-1193
• /
• 2008

Recently, mobile devices enabled with Web services are being considered as equal participants of the Web services environment. The frequent mobility of devices and the intermittent disconnection of wireless network require migrating or replicating Web services onto adjacent devices appropriately. This paper proposes an efficient method for migrating and replicating Web services among mobile devices through code splitting. Specifically, the proposed method split the source code of a Web service into sub-codes based on users' preference to its constituent operations. The sub-code with higher preference is migrated earlier than others. The proposed method also replicates a Web service to other devices to enhance its performance by considering context information such as network traffic or the parameter size of its operations.