Message Queue Telemetry Transport (MQTT) is a protocol with publish/subscribe interactions schemes and have a lightweight feature that suited for a constrained environment such in Wireless Sensor Network. This Paper presents the result of MQTT Protocols implementation in a Wireless Sensor Network (WSN) where Arduino and NRF24L01 were acted as WSN nodes, while the gateway consists of Arduino, NRF24L01 and ESP8266 Wi-Fi module as the IP based interface to the MQTT Broker. Sensor node and gateway interaction schemes were built using MQTT-SN protocols with different quality of Service (QoS) types which are QoS 0, QoS 1, and QoS 2. This paper measured several parameters which are gateway discovery process, the total number of packet loss in QoS0, data duplication along with total number of re-tries and Round-Trip Time (RTT) delay in QoS1 & QoS2. Based on the experiment, this research found several results. First, the average time for gateway discovery process is 1123.40 ms. Second, The QoS 0 is the fastest publish type protocol. However, the QoS 0 is unreliable. The QoS 0 publish type is having the most packet loss message based our experiment. Third, The QoS1 packet loss is better than QoS0 but the data duplication and several numbers of re-tries are found. Last, The QoS2 is the slowest publish type but most reliable publish message transfer. The experiment result that no packet loss occurred and the duplication data can be ignored by the gateway.

Reducing the road accident rate is one of the city goal in the area of transportation. One of the effort to reach that goal is done by deploying various signs across the road. However, the role of those road signs can be diminished once the vehicle drivers intentionally or unintentionally disobey the rule indicated on those signs. In order to increase the awareness of the driver, we can employ the vehicular network concept in which a vehicle can communicate with another vehicles or with the infrastructure installed along the road. For realizing that idea, we propose the implementation of communication equipped road sign system which consists of two components: Road Side Unit (RSU) module deployed at road sign and On Board Unit (OBU) module deployed at each vehicle. In our proposed scheme, both of the devices communicate each other through the widely-used Wi-Fi protocol (IEEE 802.11n) operating in ad-hoc mode. While a OBU equipped vehicle is moving towards the communication range of RSU, it will make an association to a predefined wireless ad-hoc network. Once it is associated, the OBU can receive message broadcast by the RSU. Upon reception, OBU display alert message indicating that the vehicle is approaching a road sign. From performance testing we observe that the proposed system can give relatively good service the vehicle moving as fast as speed 90km/h with the distance as far as 90m.

Reference broadcast synchronization and time division multiple access implementation on WSN

Decentralized and distributed blockchain technology has superior potential. Quorum, as a permissioned blockchain platform, provides enhanced privacy and performance that are suitable for enterprise needs. Cloud, as the infrastructure for Quorum-based blockchain, is vulnerable to failures. Failures originating from errors need to be tolerated through improved reliability and fault-tolerance procedures. Fault-tolerance and reliability are still challenging to implement in cloud infrastructure for Quorum-based blockchain networks. This research focuses on implementing fault-tolerance mechanisms in the provisioning of Quorum-based blockchain in a cloud environment. The research explores the use of hybrid fault tolerance by adopting a combination of reactive protocol, namely replication, and proactive protocol, namely monitoring. The replication protocol creates data redundancy with reactive treatment performed in case of failures, ensuring data availability even in failure conditions. The monitoring protocol provides real-time monitoring of the blockchain network's condition and performance, enabling proactive detection and mitigation of system failures. Overall, this research utilizes automation in its operational processes. It employs tools such as Amazon Web Services, Quorum, Docker, Terraform, Ansible, and Truffle. The research design and implementation are divided into cloud infrastructure, blockchain network, and interface. The research testing results demonstrate that the system infrastructure is capable of achieving fault tolerance using replication and monitoring protocols, as well as making transactions within the blockchain network.

This study proposes an approach to obtain maximum power via wireless power transfer using a single primary-side capacitor. It is shown that higher power is achieved when compared to the common wireless power transfer circuit under resonance with dual (primary- and secondary-side) capacitors. This approach is divided into three phases. By choosing the capacitor and frequency as freely assignable variables, we symbolically obtain a formula that allows us to determine the optimized capacitance and frequency for maximum power. To verify our method, we used a numerical analysis and compared it with an electronic circuit simulation. The symbolic formula is able to maintain maximum power despite changes in load or in the coupling coefficients.

This research focuses on the implementation and evaluation of the Flooding Time Synchronization Protocol (FTSP) in a Wireless Sensor Network (WSN) using a Star topology based on the ESP-NOW communication protocol. The study aims to assess the protocol's ability to achieve accurate time synchronization while considering the impact of clock drift. Five NodeMCU ESP8266 devices were employed, with one node as the root and four nodes as receivers. The protocol's performance was evaluated in terms of offset values between receiver local time and root time, both before and after considering clock drift, with measurements conducted in microseconds. The results highlight a consistent reduction in offsets post-synchronization, showcasing the protocol's efficiency in aligning local times. Statistical measures further confirm the protocol's reliability, as offset values converge around calculated averages. The research findings suggest the efficacy of FTSP in maintaining synchronization accuracy within WSNs, motivating further real-world evaluations and investigations into resource optimization.