• Journal of Korea Multimedia Society
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• v.10 no.10
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• pp.1338-1346
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• 2007

Beyond a simple voice service, the advances in performance and resolution of mobile handsets provides us various features in the field of mobile services. Also, advances in the human-machine interface, electronics and embedded system technologies have created the foundation for a dramatic shift in the way the vehicles are diagnosed and maintained. In this paper, we will show the vehicle diagnostic system using the mobile handset based on the OBD-II (On Board Diagnostics version II) protocol. After 2005, OBD-II standard is obligatory for all vehicles selling in Korea. Our research topics are OBD-II protocol converter for the mobile handset and the vehicle diagnostics system on WIPI(Wireless Internet Platform for Interoperability) mobile platform, which is the standard mobile platform in Korea.

• Journal of KIISE:Computing Practices and Letters
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• v.11 no.5
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• pp.401-415
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• 2005

Owing to the improved wireless communication technologies, it is possible to provide streaming service of multimedia with PDAs and mobile phones in addition to desktop PCs. Since mobile client devices have low computing power and low network bandwidth due to wireless network, the transcoding technology to adapt media for mobile client devices considering their characteristics is necessary. Transcoding servers transcode the source media to the target media within corresponding grades and provide QoS in real-time. In particular, an effective load balancing policy for transcoding servers is inevitable to support QoS for large scale mobile users. In this paper, the resource weighted load distribution policy is proposed for a fair load balance and a more scalable performance in cluster-based transcoding servers. Our proposed policy is based on the resource weighted table and number of maximum supported users, which are pre-computed for each pre-defined grade. We implement the proposed policy on cluster-based transcoding servers and evaluate its fair load distribution and scalable performance with the number of transcoding servers.

• Journal of Broadcast Engineering
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• v.11 no.2 s.31
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• pp.207-221
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• 2006

A fully automatic and computationally efficient method is proposed for intelligent display of soccer video on small multimedia mobile devices. The rapid progress of the multimedia signal processing has contributed to the extensive use of multimedia devices with a small LCD panel. With these emerging small mobile devices, the video sequences captured for standard- or HDTV broadcasting may give the small-display-viewers uncomfortable experiences in understanding what is happening in a scene. For instance, in a soccer video sequence taken by a long-shot camera technique, the tiny objects (e.g., soccer ball and players) may not be clearly viewed on the small LCD panel. Thus, an intelligent display technique is needed for small-display-viewers. To this end, one of the key technologies is to determine region of interest (ROI), which is a part of the scene that viewers pay more attention to than other regions. In this paper, the focus is on soccer video display for mobile devices. Instead of taking visual saliency into account, we take domain-specific approach to exploit the characteristics of the soccer video. The proposed scheme includes three modules; ground color learning, shot classification, and ROI determination. The experimental results show the propose scheme is capable of intelligent video display on mobile devices.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.2
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• pp.153-160
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• 2017

Recently, the demand has continued to increase for higher data rates and improved multimedia services through wireless internet access. In order to increase the data rate and link reliability, 3GPP LTE/A and IEEE 802.16e/m WiMAX systems incorporate MIMO transmission schemes. Since the hardware complexity increases with the number of transmit data streams and mobile devices have limited physical dimensions, an multiple input multiple output (MIMO) ystem with two antennas at both the transmitter and the receiver ($2{\times}2$) is considered to be a possible solution for mobile devices. In this paper, a low-complexity soft output MIMO symbol detector based on Modified-SQRD is proposed for mobile devices with two transmit and two receive antennas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1695-1703
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• 2011

According to increase of the number of electronic devices for user comfort and safety, electronic systems are being constructed by using network to effectively control the devices. In this paper, we design and implement the MOST network diagnostic system by using wireless LAN to diagnose MOST network and the devices connected by the network and to effectively manage them. MOST, which is a vehicle multimedia network standard for the next generation, is being used for construction of car infotainment systems, and enables to develop various devices which are required for them. The wireless diagnostic system implemented in this paper enables to self-diagnose MOST network and also to check errors by diagnosing status of MOST electronic devices. We also can check and manage status of a in-vehicle MOST network system using mobile devices based on wireless LAN.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1740-1746
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• 2013

Augmentative and alternative communication(AAC) is a communication tool for those with impairments or restrictions on the production or comprehension of spoken language. Traditional AAC has used a portable board with pictures and texts with which disabled person could be supported by it. Currently, smart phone based AAC researches and developments are actively studying. With emerging concepts of context-aware computing, the mobile devices can provide mobile users with timely information and location based services. We proposed a adjustable AAC system for disabled people of which has variable layouts and selectable items. We also implemented context-ware application for AAC systems including time, location and click count informations on smart phone. The system can adaptively change its layout and select AAC items depending on various situation of disabled persons.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.3A
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• pp.258-264
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• 2009

In this paper, we propose an efficient cooperative diversity scheme for mobile satellite multimedia broadcasting services. The proposed scheme is a transmit diversity technique to adapt time varying channel conditions, and we do not need any channel quality information from the return link. In the proposed scheme, we utilize space-time block coding (STBC) and rate compatible turbo codes in order to realize the transmit diversity for the mobile satellite system with several repeaters. The satellite and several repeaters operate in unison to send the encoded signals, so that the receiver may realize diversity gain. The simulation results demonstrate that the proposed scheme can provide highly improved performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.531-534
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• 2014

DLNA is an established industry standard which supports contents sharing among smart devices in home wired- and wireless-network environment and is well known in Korea as Allshare or Smartshare. The DLNA standard is implemented as built-in services in most of Android smart phones and tablets. In addition to the handheld devices, DLNA service can also be employed in speakers, printers, and so on. However, users have reported many interoperability issues between DLNA devices. Developers typically identify causes by analyzing the packet exchange information between devices. However, this approach costs them to put additional effort to filter relevant packets, to reconstruct packet exchange history and the protocol flow. Consequently, it ends up with increased development time. In this paper, we demonstrate a technique to automatically analyze and visualize the packet exchange history. We modified a router firmware to capture and store packets exchanged between DLNA devices, and then analyze and visualize the stored packet exchange history for developers. We believe that visualized packet exchange history can help developers to test the interoperability between DLNA devices with less effort, and ultimately to improve the productivity of developers.

• The KIPS Transactions:PartA
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• v.14A no.5
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• pp.295-300
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• 2007

The Linux-based embedded systems such as mobile telephones. PDAs and MP3 players are widely in use. USB(Universal Serial Bus) is the interface for data communication between the computers and these peripheral devices. Some embedded systems like intelligent home networking and multimedia streaming require guaranteed QoS(Quality of Service), which is needed for real time transmission of UDP/IP messages through USB. Although USB Ethernet driver is supported by USB Gadget API in Linux, it is unable to provide the desirable QoS required by each type or small embedded systems due to the unpredictability or TCP/IP Stack in Linux. This paper proposes IP-Over-USB to improve QoS of UDP/IP message transmission in the embedded systems using USB in Linux system.

• The Journal of the Korea Contents Association
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• v.8 no.9
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• pp.42-54
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• 2008

In recent years, embedded systems have been expanding their application domains from traditional embedded systems such as military weapons, robots, satellites and digital convergence systems such as celluar phones, PMP(Portable Multimedia Player), PDAs(Personal Digital Assistants) to Next Generation Personal Computers(NGPCs) such as eating PCs, wearable computers. The NGPCs are network-based, human-centric digital information devices diverged from the traditional PCs used mainly for document writing, internet searching and database management. Wearable computers with battery capacity and memory size limitations have to use real-time operating systems with small footprints and low power management techniques to provide user's QoS in spite of hardware constraints. In this paper, we have designed and implemented a low-power RTOS (called eRTOS) for wearable computers. The implemented eRTOS has 18KB footprints and the dynamic power management and the device power management schemes are adapted in it. Experimental results with wearable computer applications show that the low power techniques could save energy up to 47 %.