Wan-Jik Lee

Minimum LQI based On-demand Routing Protocol for Sensor Networks

A number of on-demand routing protocols for sensor networks have been proposed yet. However, the majority of proposed on-demand routing protocols for sensor networks are not suitable for a relatively poor wireless environment and sensor applications requiring reliable data transmission due to using a hop-count metric for their protocols. In this paper, we proposed a minimum LQI(Link Quality Indicator) based on-demand sensor network routing protocol that is suitable for a relatively poor wireless environment and implemented the proposed routing protocol on a TinyOS. We also compared the implemented protocol with typical hop count based routing protocol by carrying out performance experiments on a multi-hop testbed. The results from these experiments showed that the successful transmission rate of the proposed routing protocol is higher than that of typical hop count based routing protocol over a poor wireless link.

Development of PC-Based Client/Server Puretone Audiometer supporting Multiple Subject Concurrently

Current puretone audiometer takes an operation model, so called face-to-face model, in which model an audiometrist assesses only one subject at a time. Such model results in high cost and long waiting time when there exist many patients. In order to solve such a disadvantage of face-to-face model, we have developed PC-based audiometer supporting client/server model, in which model one audiometrist is able to measure several subjects concurrently. This model has an architecture like that several PCs for subjects are connected to an audiometrist`s PC through LAN and each assessment process of subjects are displayed onto audiometrist`s monitor in real time. And if necessary, it makes possible for audometrist to adjust the assessment progress of particular subject like as a face to face model.

Design and Implementation of Tiny TCP/IPv6 Protocol for Wireless Sensor Networks

As a core technology realizing ubiquitous world, recent researches are being concentrated to wireless sensor network. However, most research results were focused to the sensor network technology itself, even though interworking between the sensor network and Internet is also one of primitive requirements for ubiquitous world. In this paper, we design the tiny TCP/IPv6 profile which makes it possible to inter-connect the sensor network device to IPv6 based Internet. To confirm operation of the designed profile, we experimentally implemented and evaluated minimum TCP/IPv6 based on TinyOS. The evaluation result shows that throughput of our tiny TCP/IPv6 is almost same as that of TinyOS component.

A Secure Packet Filtering Mechanism for Tunneling over Internet

Unlike Internet design policies of early stage, various types of tunneling are currently used in Internet for IPv4/IPv6 transition, IP multicasting and IP mobility. As tunneled packets have dual IP headers, general firewall systems apply the filtering rules only to the outer header but not to the inner header when these packets pass the firewall. Thus, many present firewall systems may have serious security problems to packet filtering for tunneled packets. To resolve this issue, a new packet filtering mechanism to filter tunneled packets is proposed in this paper. We design and implement the packet filtering mechanism by using Linux Netfilter. Through this study, the packet filtering system was also found operating correctly in the IPv6-in-IPv4/IP-in-IP tunneling.

Hopping Routing Scheme to Resolve the Hot Spot Problem of Periodic Monitoring Services in Wireless Sensor Networks

Abstract In this paper we proposed a hopping routing scheme to resolve the hot spot problem for periodic monitoring services in wireless sensor networks. Our hopping routing scheme constructs load balanced routing path, where an amount of energy consumption of all nodes in the sensor networks is predictable. Load balanced routing paths can be obtained from horizontal hopping transmission scheme which balances the load of the sensor nodes in the same area, and also from vertical hopping transmission scheme which balances the load of the sensor nodes in the other area. The direct transmission count numbers as load balancing parameter for vertical hopping transmission are derived using the energy consumption model of the sensor nodes. The experimental results show that the proposed hopping scheme resolves the hot spot problem effectively. The efficiency of hopping routing scheme is also shown by comparison with other routing scheme such as multi-hop, direct transmission and clustering.Key Words : Hot Spot Problem, Hopping Routing, Load Balanced Routing Path

Efficient Method to Support Mobile Virtualization-based Cloud Resource Management

Abstract Recently, various cloud service has been being provided on mobile devices as well as desktop pc and server computer. Also, Smartphone users are very rapidly increasing, and they are using it for enjoying various services(cloud service, game, banking service, mobile office, etc.). So, research to utilize resources on mobile device has been conducted. In this paper, We have suggested efficient method of cloud resource management by using information of available physical resources(CPU, memory, storage, etc.) between mobile devices, and information of physical resource in mobile device. Suggested technology is possible to guarantee real-time process and efficiently manage resources. Key Words : Mobile Virtualization, Mobile Cloud Computing, Cloud Resource Management Received 2 January 2014, Revised 7 February 2014Accepted 20 February 2014Corresponding Author: Jooman Kim(Pusan National University) Email: joomkim@pusan.ac.krⒸ The Society of Digital Policy & Management. All rights reserved. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.otg/licenses/by-nc/3.0), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is ISSN:1738-1916 properly cited.

Automatic Drawing Conformity Inspection System Using Image Features Matching and Bilinear Interpolation

To evaluate whether or not their product is in conformity with its drawing, today`s factories manufacturing rubber and/or plastic products use manual process. In manual conformity inspection process, a person decides conformity as comparing drawing to image of product with his eyes. The manual process is tedious and time-consuming in addition that it is impossible to automatically record various informations related to inspection. To solve such problems, this paper proposes automatic drawing conformity inspection system based on computer vision technologies such as image feature matching and bilinear interpolation. The test results show that proposed system is a lot faster when comparing with manual system.

Dynamic Transmission Target Selection Scheme for Load-Balancing in WSN

We studied a dynamic transmission target selection scheme for load-balancing in WSN. The goal is for the energy consumption of packet transmission for all nodes to be nearly same as possible. For a load-balancing, it should be needed to predict the scale of the transmission energy of all nodes. In multihop transmission mode, a fixed transmission path is necessary for the load-balancing of nodes that are at the same hop distance from the sink node (we call as horizontal hopping transmission), and a variable range transmission mode is needed for the load-balancing of nodes that are at different hop distances from the sink node(we call as vertical hopping transmission). In this paper, we developed a dynamic transmission target selection scheme for horizontal-hopping and vertical-hopping transmission. The performance evaluation results show that the energy consumption of all the nodes was nearly the same, and the performance achieved was superior to that of existing load-balancing schemes.

An Energy Efficient On-Demand Routing Scheme Based on Link Quality for Wireless Sensor Networks

Most of legacy routing schemes for wireless sensor networks do not consider the retransmission energy consumption when they predict the transmission energy consumption. They usually select the path based on hop by hop routing technology. Therefore these routing schemes have a problem in that they may exclude the path even though the path has better energy efficiency. In this paper, we proposed an energy aware routing scheme which transmits the accumulated predicted transmission energy value considering retransmission and minimum residual energy of node of whole candidate paths. A destination node selects the best energy efficient path within received candidate paths using energy related information. To evaluate the performance of our proposed scheme, the performance simulation has been compared to that of legacy on-demand routing scheme.