Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
IEMEK Journal of Embedded Systems and Applications
Journal Basic Information
Journal DOI :
Institute of Embedded Engineering of Korea
Editor in Chief :
Volume & Issues
Volume 2, Issue 4 - Dec 2007
Volume 2, Issue 3 - Sep 2007
Volume 2, Issue 2 - Jun 2007
Volume 2, Issue 1 - Mar 2007
Selecting the target year
Improved FGS Coding System Based on Sign-bit Reduction in Embedded Bit-plane Coding
Seo, Kwang-Deok ; Davies, Robert J. ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 129~137
MPEG-4 FGS is one of scalable video coding schemes specified In ISO/IEC 14496-2 Amendment 2, and particularly standardized as a scheme for providing fine granular quality and temporal scalabilities. In this paper, we propose a sign-bit reduction technique in embedded bit-plane coding to enhance the coding efficiency of MPEG-4 FGS system. The general structure of the FGS system for the proposed scheme is based on the standard MPEG-4 FGS system. The proposed FGS enhancement-layer encoder takes as input the difference between the original DCT coefficient and the decision level of the quantizer instead of the difference between the original DCT coefficient and its reconstruction level. By this approach, the sign information of the enhancement-layer DCT coefficients can be the same as that of the base-layer ones at the same frequency index in DCT domain. Thus, overhead bits required for coding a lot of sign information of the enhancement-layer DCT coefficients in embedded bit-plane coding can be removed from the generated bitstream. It is shown by simulations that the proposed FGS coding system provides better coding performance, compared to the MPEG-4 FGS system in terms of compression efficiency.
Time Synchnorinization Scheme for Multi-Hop Wireless Sensor Network
Kim, Gi-Hyeon ; Eom, Tae-Hwan ; Hong, Won-Kee ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 138~144
Wireless Sensor Network(WSN) consists of a lot of light-weight sensor nodes with the capability of wireless communication. Studies have been done to improve stability and fault-tolerancy of WSN because the sensor nodes are basically vulnerable to the harsh environment. Specially, the time synchronization among sensor nodes becomes a challenging issue in WSN. All the local times should always keep the same with each other in the sensor field to perform data aggregation and energy-aware communication in WSN. In this paper, a new time synchronization technique is proposed to operate efficiently irrespective of the number of sensor nodes and the number of hops needed to cover all sensor nodes for synchronization. Simulation results show that the proposed technique has the lowest amount of packet traffic among the several time synchronization techniques.
Design and Evaluation of Function-granularity kernel update in dynamic manner
Park, Hyun-Chan ; Kim, Se-Won ; Yoo, Chuck ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 145~154
Dynamic update of kernel can change kernel functionality and fix bugs in runtime. Dynamic update is important because it leverages availability, reliability and flexibility of kernel. An instruction-granularity update technique has been used for dynamic update. However, it is difficult to apply update technique for a commodity operating system kernel because development and maintenance of update code must be performed with assembly language. To overcome this difficulty, we design the function-granularity dynamic update system which uses high-level language such as C language. The proposed update system makes the development and execution of update convenient by providing the development environment for update code which is same for kernel development. We implement this system for Linux and demonstrate an example of update for do_coredump() function which is reported it has a vulnerable point for security. The update was successfully executed.
A New Framework for Ad Hoc Network routing Protocol without Destination Sequence Number
Seo, Jae-Hong ; Jung, Ho-Youl ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 155~163
In Ad Hoc Networks, a connection breaks due to the irregular movement of mobile nodes and the inherent characteristics of the wireless medium such as the interference and the multi-path fading. AODV, a typical on-demand routing protocol in Ad Hoc networks, uses Destination sequence numbering for loop-free, but it may cause RREQ broadcast storm problem. This paper proposes AODV_ods that does not need destination sequence number, in routing message and routing table without routing loop. To show the effectiveness of the proposed scheme, we performed extensive simulation with NS-2. The simulation results show that the proposed ADOV_ods efficiently uses wireless bandwidth compare to the original AODV. Finally AODV ods reduces the routing overhead, end to end delay and increases the overall packet delivery ratio.
GUI-based Power Consumption Analysis Tool for Lower Power Embedded S/W Development in ESTO
Kim, Doo-Hyun ; Lee, Keun Soo ; Jung, Changhee ; Woo, Duk-Kyun ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 164~173
In this paper, we present a time-triggered mechanism for providing energy consumption profiles in the level of C functions. The similar mechanisms have already been introduced at the previous researches such as PowerScope and ePRO. Instead, we, in this paper, introduce our efforts to extend these researches to incorporate power domains and DVS(Dynamic Voltage Scaling), then to provide GUI-based tool as a plug-in to ESTO which is an IDE for Embedded S/W development based on Eclipse. From our experimental results, we could conclude that our approach worked and produced consistent energy consumption profiles on the DVS-applied program codes, and also displayed function level and time domain power consumption information with diverse presentation skills such as tables, phi-chart, bar-chart, 2-D graphs, consequently, is expected to provide more ease-to-use and productive IDE for lower power embedded S/W developers.
Design and Implementation of Vertical Handover System for Next-generation Networks
Kim, Yong-Sung ; Suh, Young-Joo ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 174~183
A Technique to Enhance Performance of Log-based Flash Memory File Systems
Ryu, Junkil ; Park, Chanik ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 184~193
Flash memory adoption in the mobile devices is increasing or vanous multimedia services such as audio, videos, and games. Although the traditional research issues such as out-place update, garbage collection, and wear-leveling are important, the performance, memory usage, and fast mount issues of flash memory file system are becoming much more important than ever because flash memory capacity is rapidly increasing. In this paper, we address the problems of the existing log-based flash memory file systems analytically and propose an efficient log-based file system, which produces higher performance, less memory usage and mount time than the existing log-based file systems. Our ideas are applied to a well-known log-based flash memory file system (YAFFS2) and the performance tests are conducted by comparing our prototype with YAFFS2. The experimental results show that our prototype achieves higher performance, less system memory usage, and faster mounting than YAFFS2, which is better than JFFS2.
Power Management for Mobile Terminal
Lee, Junghee ; Park, Hojun ; Kim, Jaemyoung ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 194~201
As the performance of the mobile terminal becomes higher, the power consumption gradually increases. As a result, power management is one of the most important issues in mobile system with battery. In this paper, we describe an DPM(Dynamic Power Management) using DVS(Dynamic Power Management) as a power management mechanism in Qplus operating system. DVS generally considers a specific device such as CPU, whereas we consider the relations with other hardware components as well as each component. We specially focus on the relation between CPU, memory and LCD devices. We also designs a kernel monitor to collect information to decide the policy for power management. According to the experimental results, the proposed method enables to save much power.
A Scheme to Categorize Ubiquitous Sensor Network Services and Their Practical Issues
Eun, Seongbae ; So, Sun Sup ; Chae, Yigeun ;
IEMEK Journal of Embedded Systems and Applications, volume 2, issue 3, 2007, Pages 202~208
Recently, a lot of research have been studied to apply wireless sensor networks to USN applications. The characteristics of USN applications is that they are varied according to the sort of sensors and sensing objects. They includes military applications, water pollusion monitoring, intelligent traffic system, farm, logistics, location position applications, and so on. There is no traditional method to classify these applications. In this paper, we propose a taxonomy scheme to classify USN applications. The criteria is based on 3 properties, the criticalness of services, the mobility of sensing entity, and the mobility of sensed objects, to classify them into 8 groups. We also describe the technical issues and related works in them. Our taxonomy can make USN applications to be easily understood and memorized.