Kyung-jun Kim

Comparative study of physical methods for lipid oxidation measurement in oils

For the determination of lipid oxidation in oils, electrical, optical, spectroscopic and extraction methods were investigated using rice bran oil and doubly-fractionated palm olein as model systems. The oxidized polar components and dielectric constant of rice bran oil increased very similarly with those of double-fractionated palm olein. In the case of rice bran oil, all of the test methods were shown to possess good statistical correlations. Polar components, dielectric constant, refractive index and polymer content showed relatively better correlations. It was shown that diene and triene content determined by spectroscopic methods was not suitable for more saturated oils such as palm olein.

Traffic management strategy for delay-tolerant networks

Messages in delay-tolerant networks (DTNs) are generally classified by relative priority into low, medium, and high priority classes, thus creating challenges in structuring scheduling and drop policies of a traffic management system. This study proposes a novel traffic management strategy for DTNs. The proposed scheme improves message deliveries of different priority classes by utilizing message properties such as estimated total number of replicas, elapsed time, and remaining time-to-live. A delete mechanism of delivered messages is also incorporated to use buffer space efficiently. The performance of the proposed strategy is verified via implementation of a simulation model along with existing scheduling and drop policies and is tested with two well-known real-world trace datasets. The results demonstrate that the proposed strategy yields improved message deliveries of high priority as well as medium and low priority classes.

ADSR: Angle-Based Multi-hop Routing Strategy for Mobile Wireless Sensor Networks

Though Dynamic Source Routing (DSR) is a popular on-demand algorithm designed to restrict the bandwidth consumed by control packets, the flooding of Route Request (RREQ) packets to find paths to a destination makes it difficult to apply DSR to wireless sensor networks (WSNs), which have tiny sensor nodes of limited memory and power. In this study, an angle-based multi-hop routing algorithm for mobile WSNs, which is termed ADSR, is proposed. ADSR is a variation of DSR utilizing the location information of a neighboring mobile node and a stationary sink to make the decision of dropping or rebroadcasting the RREQ packet received. ADSR focuses on reducing the number of control packets and, as a result, ADSR improves data deliveries and End-to-End delay. The experimental results using Qualnet modeler software prove that ADSR outperforms DSR in terms of overhead, data delivery, and End-to-End delay regardless of the moving speed or number of sensor nodes.