Kyeong Tae Kim

A Level-based Key Management for both In-Network Processing and Mobility in WSNs

We present a new infrastructure to support secure and energy-efficient multicast communication for both in-network processing and mobility in WSNs. A level-based hierarchy is used for the design. It subdivides the group routing tree into level and branches. On top of it, the secure packet forward (SPF) scheme and re-keying algorithm are implemented. The secure packet forward (SPF) mechanism efficiently detects and mitigates the Byzantine behavior as avoiding interference between data aggregation and message encryption. The re-keying algorithm effectively handles the impact of mobility on key establishment while minimizing the number of messages to be exchanged. Simulation results show that the proposed approach can derive the benefits of in-network processing with reasonable routing overhead minimizing the effects of faulty nodes. Moreover, it achieves dramatically lower overhead than traditional secure multicast protocols for mobility management.

An industrial IoT MAC protocol based on IEEE 802.15.4e TSCH for a large-scale network

IEEE 802.15.4e TSCH MAC is widely used for the industrial market, which require ultra-high reliability and ultra-low power. However, the significance of the TSCH is missing, which is a management function to build and maintain the communication schedule. We address several limitations for Ipv6 over IEEE 802.15.4e TSCH in a large-scale network and propose an enhanced scheme which deals with the configuration of Slotframes, Linkset slots, EB(Enhanced Beacon) management and scheduling information. It supports a dynamic schedule management based on observed resource usage, which achieves industrial-grade performance in terms of jitter, latency, scalability, reliability and low-power consumption.

SAEP: Secure and Accurate and Energy-Efficient Time Synchronization in Wireless Sensor Networks

We have developed a secure, accurate and energy-efficient time synchronization protocol (SAEP). First, SAEP achieves accurate time synchronization service with significantly reducing the number of message exchanges. Second, SAEP safeguards Byzantine failure, in which nodes drop, modify, or delay time information in an attempt to disrupt the time synchronization service in multi-hop networks. SAEP takes a distributed approach where each sensor independently makes decisions based only on the information collected from multiple adjacent nodes, thus achieving a high level of resistance to various attacks at a minimizing energy cost. In our experiment SAEP outperforms the existing time synchronization protocol in accuracy, energy consumption, and it is even resilient to multiple capture attacks.

Router design for DDS: Architecture and performance evaluation

The current Data Distribution Service for Real-Time Systems (DDS) is mainly designed for transmission in a single local network domain. However, when DDS applications communicate with other applications in different network domains over WAN, the DDS could face severe problems, because most ISPs in WAN do not allow multicast and UDP flows. In this paper, we propose a router design for DDS. While keeping the semantics of the DDS, the proposed DDS router provides an efficient data distribution over WAN using the local recovery and overlay multicast. Through the NS-3 simulations, we show that the system with the DDS routers outperforms the legacy unicast based communication method in terms of the scalability and robustness.

VTM-MAC: Vehicle traffic monitoring MAC in WSNs

Traffic monitoring and control applications in WSNs provide a number of challenges related to wireless communication between sensor nodes. In this paper, we propose a Vehicle Traffic Monitoring MAC (VTM-MAC) protocol in a reliable and low-cost collision warning system utilizing WSNs technologies. VTM-MAC adopts the access method based on TDMA and uses superframe structure which considers the relay of packets from a source (sensor) to a destination (basestation) via sensor to sensor communication. It provide a delay bound on end-to-end transmission with high reliability in a multi-hop network. Moreover, VTM-MAC utilizes a multiple path for data forwarding via a sensor node, which supports reliable data delivery during same superframe period. For energy saving and minimizing the latency, it dynamically allocates time slots and adjusts its period based on weighted moving average of each data gathering path depends on traffic pattern. We also provide two time synchronization protocols viz., a Beacon based Time Synchronization (BTS) that is one-way broadcast synchronization scheme which can synchronize a network wide sensor nodes with a beacon, and a Elapsed Time Synchronization (ETS) that is translational synchronization scheme between event time and elapsed time. Both of techniques well integrate with the VTM-MAC to minimize the jitter and achieve microsecond level time synchronization accuracy. Our evaluation shows that VTM-MAC plays an important role in the beneficial impact on intelligent transportation systems in the real-road environment.