Gold is of considerable interest for electrochemical active surfaces because thiol-modified chemicals and biomolecules can be easily immobilized with a simple procedure. However, most gold surfaces are damaged with repetitive measurements, so they are difficult to reuse. Here we demonstrate a novel electrochemical cleaning method of gold surfaces to reuse electrodes with a simple protocol that is easy and nontoxic. This electrochemical cleaning consists of two steps by using different solutions. The 1st step is a cyclic voltammetry sweep using a very low concentration of sulfuric acid, and the 2nd step is a cyclic voltammetry sweep using potassium ferricyanide. Different cleaning methods were also considered for comparison. Consequently, after assembling and desorption of the cell and antigen, the changes in gold electrode performance, as immunosensor and cytosensor, were investigated by electrochemical impedance and cyclic voltammetry. It was found that repetitive measurement is possible until five times while maintaining the reproducibility. It is believed that this method is capable of enabling reuse of gold electrodes and can be used for long-term and accurate monitoring of biological effects, especially at a low cost.

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The IEEE 802.15.4-2015 TSCH (Time Slotted Channel Hopping) standard provides highreliability, deterministic delay, and energy efficiency with the channel hopping and the TDMA. The standard does not specify the scheduling method, which is an essential part of the solution. One of the representative studies in TSCH scheduling is Orchestra. It is an autonomous scheduling method with minimal overhead that does not require a negotiation process between nodes. However, with high traffic load, performance of the Orchestra is greatly degraded because of its fixed schedule. If a node has children, continuous collisions occur in the slot of the node. We propose a novel algorithm called SRCA (Slot Reallocation for Collision Avoidance), as a solution for this problem. The SRCA autonomously updates the schedule. When a child requests a slot reallocation, the parent allocates a new slot with a low probability of collision. Another algorithm called SJCA (Slot reJection for Collision Avoidance) is further proposed in this work. It improves the SRCA to operate in an environment with interference where a sending node can disturb a transmission from a hidden node. In the SJCA, a node determines whether a collision due to interference will occur in the slot newly allocated by the parent. If so, it rejects the slot and requests again. We compare the performance of the SRCA and the SJCA against the Orchestra and e-TSCH-Orch through simulations. It is confirmed that the SJCA is robust to interference. In most cases, the SJCA shows better performance of PAR (Packet Acknowledgement Ratio), PLR (Packet Loss Rate), and latency than others. It is also verified that the SJCA provides high-reliability and low latency compared to existing technologies.

In mission-critical applications such as vehicular networks, distributed robotics, and other cyber-physical systems, the requirements for latency are more stringent than traditional applications. Among them, autonomous V2V communication is a rapidly emerging domain of applications with a few milliseconds' latency requirements. Today's systems utilizing 802.11p or LTE-direct standards are not primarily designed for ultra-low latency. Because the medium access function contributes to a significant portion of the total latency, it is necessary to modify Layer2 in order to solve the problem. Focusing on MAC layer, we developed a scalable and latency-guaranteed MAC by devising Autonomous TDMA (ATDMA) in which autonomous joining/leaving is allowed without scheduling by coordinator. We also evaluated the performance of the algorithm by comparing with the WAVE protocol.

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