PROF. SHOW-SHIOW TZENG
Shiow-Shiow Tzeng (Member, IEEE) received the B.S. degree in computer information science from National Chiao Tung University, Taiwan, in 1995, the M.S. degree in computer science from National Tsing Hua University, Taiwan, in 1997, and the Ph.D. degree in computer science from National Tsing Hua University, Taiwan, in 2005. He was elected an honorary member of the Phi Tau Phi Scholastic Honor Society of the Republic of China by National Tsing Hua University. From August 2005 to July 2020, he was on the faculty of the Department of Optoelectronics and Communication Engineering at National Kaohsiung Normal University, Kaohsiung, Taiwan, R.O.C. Since August 2020, he has been a Professor in the Department of Electrical Engineering at National Kaohsiung Normal University, Kaohsiung, Taiwan. His research interests include computer networks, wireless networks, cognitive radio networks, machine-type communication networks, vehicular networks, energy-efficient communication networks, Internet of Things, resource management, quality-of-services, age of information, and blockchain.
MY LATEST RESEARCH
Enhanced Mini-Slotted Threshold ALOHA for Age of Information and Energy Efficiency in Wireless Sensor Networks (S.S.Tzeng, Y.J. Lin, and S.W. Wang, IEEE Sensors Journal)
The Age of Information (AoI) is a critical metric for ensuring data freshness in wireless sensor networks, where timely data updates and energy efficiency are key to sustainable operation. While Mini-Slotted Threshold ALOHA (MiSTA) improves upon Slotted ALOHA (SA) and Threshold ALOHA (TA) by reducing the average AoI (AAoI), data sub-slot remains idle whenever no device sends requests in the mini-slot. To address this, we propose the Enhanced Mini-Slotted Threshold ALOHA (EMiSTA) protocol, which utilizes negative acknowledgments to trigger a secondary access opportunity in these idle sub-slots, significantly reducing the AAoI. Furthermore, an energy-efficient variant, EMiSTA-RE, is developed using a randomized pre-determination mechanism, allowing devices to probabilistically enter sleep mode before the next transmission attempt, thereby minimizing unnecessary energy consumption. We present a comprehensive analysis of the proposed schemes, validated by simulations. Results show that the proposed schemes yield a lower AAoI than other schemes, including MiSTA, TA, and SA, even under energy consumption constraints. Moreover, EMiSTA-RE reduces energy consumption more than EMiSTA. Considering mini-slot overhead, the proposed schemes outperform MiSTA and SA, and surpass TA when the overhead ratio is below 0.75. Furthermore, the proposed schemes achieve a lower asymptotic AAoI of approximately 0.8083n, where n is the network size, and EMiSTA-RE achieves constant energy consumption. In summary, EMiSTA-RE provides an effective solution for improving both data freshness and energy consumption.
SLChain: A Stochastic Lightweight Blockchain With Selfish Mining Attack Mitigation (S.W. Wang, S.S.Tzeng, and L.C. Wang, IEEE Internet of Things Journal)
High computational power consumption is a significant problem in a proof-of-work (PoW) blockchain. Restricting the total mining power or the number of miners is a possible solution to save computational power consumption. However, reducing the mining power or the number of miners raises concerns about fairness and security. In this article, we propose a stochastic lightweight blockchain (SLChain) in which a random subset of miners is selected to mine the next block. In the proposed SLChain, the power consumption is significantly reduced while maintaining fairness among miners, robustness to multiple types of attacks, and block time consistency. Furthermore, the proposed SLChain can mitigate selfish mining attacks. We derive an analytical model to calculate the rewards earned by selfish miners. Simulations are conducted to study the accuracy of the proposed analytical model. From the numerical results, we found that the profitable threshold of selfish mining attacks increases from 25% to 29.29% in the proposed SLChain. In summary, the proposed SLChain can simultaneously reduce computational power consumption, maintain fairness and security levels, ensure block time consistency, and mitigate selfish mining attacks simultaneously.
