Sang Oh Park

Consideration on the brute-force attack cost and retrieval cost

A radio-frequency identification (RFID) system is a promising automatic identification technology that uses communication via radio waves to identify and track moving objects. RFID systems are expected to replace bar-code systems in object identification fields in the future, but various security problems are obstructing their diffusion. The most important problem of RFID system is that an attacker can access the tag information, which raises privacy infringement and forgery problems. This paper proposes a hash-based RFID tag mutual authentication protocol to solve these security problems of RFID systems. The proposed protocol is designed to demand high cost of acquiring the tag information for attackers.

A dynamic control middleware for cyber physical systems on an IPv6-based global network

SUMMARY A cyber physical system (CPS) is a deeply embedded system that can be applied to home devices, medical equipment, cars, and so on. Because it is expected that a CPS system will be integrated with other CPSes designed for various areas to ultimately create a global CPS network, IPv6 is suitable for these large-scale integrated network environments. In addition, it is important to reduce high network load for efficient device control. This paper proposes a dynamic control middleware for an efficient search and control of devices on an IPv6-based global network from anywhere through smartphones along with a new mechanism intended to drastically reduce the number of messages that are generated for searching devices. We construct an IPv6-based testbed using laptops and smartphones to demonstrate that this middleware can be adopted by mobile devices for dynamic remote control of home devices. Copyright

An efficient multimedia file system for NAND flash memory storage

Since the existing NAND flash memory file systems manage file data in page units, the memory usage increases greatly as the number and size of files increase, and the area to scan at the mounting time increases linearly as well. To resolve these problems, this paper suggests data management in segment units for more efficient processing of multimedia files to reduce memory usage and to improve reading and writing performance. In addition, it suggests a new index structure and garbage collection method for multimedia files to reduce the mounting time and to improve the wear-leveling effectiveness. This approach shows better performance for multimedia files than existing file systems in terms of reading, writing, memory usage, mounting time, and garbage collection.

Adaptive power management system for mobile multimedia device

Recently, methods that combine the concepts of dynamic voltage scaling (DVS) and dynamic power management (DPM) approaches have been proposed for a single task. This study proposes adaptive power management system (APMS), which utilises useful features of both DPM and DVS and an existing pattern analysis algorithm, and new break even time-based task partition scheduling (BET-BTPS). APMS splits tasks based on BET to reduce the total power consumption of multiple multimedia applications in a mobile embedded system environment and analyses their usage patterns of peripheral devices and apply the results to their scheduling for further reduction of power consumption. It also takes into account the additional time delay that may occur while invoking and executing a timeslot scheduler to guarantee real-time services for multimedia data streams when the scheduling of APMS is in effect. In order to determine the optimal processor speed that minimises power consumption, the extra consumption required by the scheduler is compared with that reduced by BTPS. The proposed approach demonstrates better performance compared to existing power management schemes not only for single task but multiple tasks.

Group-Aware Social Trust Management for a Movie Recommender System

This paper presents an interactive movie recommender system for constructing an intelligent home network system. The proposed model is based on a group-aware social trust management, one of the new paradigms for personalized recommendation. In this paper, we show the concept model of group-aware social networks for the proposal and a prototype implementation.

A Hierarchical Middleware Architecture for Efficient Home Control through an IPv6-Based Global Network

A cyber physical systems (CPS) are deeply embedded systems that can be applied to home devices, medical equipments, cars, and etc. Since it is expected that a CPS system will be integrated with other CPSes designed for various areas to ultimately create a global CPS network covering a global network, IPv6 is suitable to these large-scaled integrated network environments. This paper proposes a hierarchical middleware architecture for an efficient search and control of home devices on an IPv6-based global network from anywhere through smart phones along with a new mechanism intended to drastically reduce the number of messages that are generated for searching devices.

An Adaptive Power Management System for multimedia applications using data stream partitioning

This paper suggests a Break Even Time-based Adaptive Power Management System which partitions a multimedia data stream into a sequence of substreams. APMS shows good performance for multimedia applications which periodically access multimedia files.

An Efficient Array File System for Multiple Small-Capacity NAND Flash Memories

The existing NAND flash memory file systems have not taken into account multiple NAND flash memories for large-capacity storage. To resolve these problems, this paper suggests a new file system called NAFS for large-capacity storage with multiple small-capacity NAND flash memories. It adopts a new cache policy and mount scheme in order to improve read and write performance and to reduce the mount time. Our performance results show that NAFS is more suitable for large-capacity storage than conventional NAND file systems such as YAFFS2 and JFFS2 and a disk-based file system for Linux such as HDD-RAID5-EXT3.

An Efficient Power Management System for Mobile Multimedia Devices

Recently, methods that combine the concepts of Dynamic Voltage Scaling (DVS) and Dynamic Power Management (DPM) approaches have been proposed for a single task. This paper proposes Adaptive Power Management System (APMS), which utilizes useful features of both DPM and DVS and an existing pattern analysis algorithm, and new BET-based Task Partition Scheduling (BTPS). In order to determine the optimal processor speed that minimizes power consumption, the extra consumption required by the scheduler is compared with that reduced by BTPS. The proposed approach demonstrates better performance compared to existing power management schemes for not only a single task but multiple tasks.

An efficient file system for large-capacity storage with multiple NAND flash memories

This paper suggests various schemes for a file system which is suitable for large-capacity storage with multiple NAND flash memories. The file system can be adopted by multimedia devices which require light non-volatile large storage.