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( Fei Shi ),( Jooseok Song ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.6
The characteristics of ad hoc networks, such as the absence of infrastructure, a dynamic topology, a shared wireless medium and a resource-constrained environment pose various security challenges. Most previous studies focused on the detection of misbehavior after it had occurred. However, in this paper we propose a new way of thinking to evade the occurrence of misbehavior. In our scheme, we firstly present a clustering algorithm that employs a powerful analytic hierarchy process methodology to elect a clusterhead for each cluster. The clusterhead in each cluster is then allowed to assign the backoff values to its members, i.e., originators, rather than permitting the originators to choose the backoff values by themselves. Through this media access control layer misbehavior detection mechanism, the misuse of the backoff in the media access control layer in the 802.11 distributed coordination function can be detected.
Highly Regioselective Preparation and Characterization of New 6-O-Substituted Dieckol Derivatives
Yongkyun Kim,Jooseok Shin,Su Min Kang,Jinyoung Song,Hyeon-Cheol Shin,Young-Sam Keum,Hye Jeong Hwang,Kwangyong Park 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.91 No.-
Dieckol is a brown algae-derived polyphenol that has broad bioactivity and low toxicity. Therefore, it is apromising lead compound for the development of therapeutic agents to treat various pathologicalconditions, including viral infections, allergies, diabetes, skin ageing, cancers, and neurodegenerativeconditions. To exploit the pharmacological potential of dieckol, its stability, solubility, pharmacokinetics,and drug delivery must be improved. This can be achieved by the controlled modification of the hydroxylgroups, but the presence of eleven nearly equivalent hydroxyl groups makes the task highly challenging. In this study, the regioselectivities infive substitution reactions of the hydroxyl groups of dieckol undervarious SN2 reaction conditions were investigated. After reaction optimization,five substituents (methyl,benzyl, methoxymethyl, 3-hydroxypropyl, and 3-(ethoxycarbonyl)propyl) could be introduced at the 6-Oposition of dieckol with surprisingly high regioselectivity, as confirmed by 2D-NMR spectroscopicanalyses. The prepared dieckol derivatives showed antioxidant and anticancer activities analogous tothose of unmodified dieckol, indicating that the mono-O-substitutions did not affect the biochemical andbiological characteristics of dieckol. Therefore, the proposed methodology for the mono-O-substitutionof a specific oxygen of dieckol is a powerful tool to add various pharmaceutical attributes to dieckol, thuscontributing to the development of various dieckol-based drug candidates.
TCP Aware Link Layer Agent for Seamless Vertical Handoff in the Cellular/WLAN Integrated Network
JongHyup Lee,JooSeok Song IEEE 2010 IEEE communications letters Vol.14 No.11
<P>In cellular/WLAN integrated networks, a TCP-aware link layer agent, called VH agent, is proposed to resolve the packet reordering problem of Downward Vertical HandOver (DVHO) and the premature timeout and excessive transmission that occur during Upward VHO (UVHO). The simulation results show that the proposed agent achieves better performance with respect to throughput and end-to-end delay, compared with TCP NewReno and Westwood.</P>
A Dual Key-Based Activation Scheme for Secure LoRaWAN
Kim, Jaehyu,Song, JooSeok WILEY INTERSCIENCE 2017 WIRELESS COMMUNICATIONS AND MOBILE COMPUTING Vol.2017 No.-
<P>With the advent of the Internet of Things (IoT) era, we are experiencing rapid technological progress. Billions of devices are connected to each other, and our homes, cities, hospitals, and schools are getting smarter and smarter. However, to realize the IoT, several challenging issues such as connecting resource-constrained devices to the Internet must be resolved. Recently introduced Low Power Wide Area Network (LPWAN) technologies have been devised to resolve this issue. Among many LPWAN candidates, the Long Range (LoRa) is one of the most promising technologies. The Long Range Wide Area Network (LoRaWAN) is a communication protocol for LoRa that provides basic security mechanisms. However, some security loopholes exist in LoRaWAN’s key update and session key generation. In this paper, we propose a dual key-based activation scheme for LoRaWAN. It resolves the problem of key updates not being fully supported. In addition, our scheme facilitates each layer in generating its own session key directly, which ensures the independence of all layers. Real-world experimental results compared with the original scheme show that the proposed scheme is totally feasible in terms of delay and battery consumption.</P>