This article presents a systematic design methodology for multi-input piezoelectric energy harvesting (PEH) using collaborative-flip synchronized switch harvesting on capacitors (CF-SSHCs). We address a fundamental scaling limitation: conventional synchronized switch harvesting on capacitor (SSHC) efficiency degrades as the number of parallel transducers increases due to rising equivalent capacitance. Starting from the theoretical foundations of a two-transducer single-stage topology, we develop closed-form expressions for the voltage flipping factor and power extraction that reveal a 7.4% maximum power improvement over conventional SSHC. Extending to multistage architectures, results show that an 8-stage configuration achieves 32.2% power enhancement through 33 collaborative-flipping phases. For generalized$M$-input$N$-stage systems, the derived analytical framework demonstrates that the maximum output power improvement ratio (MOPIR) scales from 3.8 to 9 as transducer count increases from 1 to 60 in an 8-stage implementation. We formulate an optimization algorithm for automated parameter selection and provide closed-form design equations considering practical issues, including phase asynchrony and capacitance mismatch. This work establishes a complete theoretical framework enabling systematic design of multitransducer energy harvesting interfaces rather than empirical topology exploration.

Insulated gate bipolar transistors (IGBTs) are the key component in power electronics, and the intricate relationship between their performance and structural parameters poses a formidable challenge in the design process. This article proposes an automatic optimal design method for IGBT structural parameters to leverage the pretrained machine learning (ML) model to efficiently predict the initial IGBT device’s performance, followed by utilizing the differential evolution (DE) algorithm to automatically adjust structural parameters based on the disparity between predicted and expected device performance until the expected performance is achieved. The method is validated in the design of punch-through IGBTs (PT-IGBTs) and trench gate field-stop IGBTs (FS-IGBTs), and the performance of technology computer-aided design (TCAD) simulation of the designed device is similar to the target performance. In particular, the simulation results of the designed FS-IGBT are highly fitted to the datasheet of the commercial device, which verifies the generalizability and effectiveness of the method. In addition, comparative analyses with various algorithms show DE provides the fastest optimization and extraordinary robustness under the exact specifications. Crucially, the proposed design scheme aligns with semiconductor physics. The method simplifies IGBT design without the need for manual tuning and TCAD tool simulation.

Soft handoff in WCDMA systems allows multi connection between the user and base stations during handoff, in contrast to single connection in hard handoff. But multi connection flexibility leads to a trade-off between quality of service for the user and the system downlink capacity. The heterogeneous wireless networks consist of WCDMA and WLAN systems, which operate at different frequency with no direct interference. Therefore, a vertical soft handoff between downlink shared channels from WCDMA and WLAN will not suffer similar side effects as the horizontal soft handoff in WCDMA systems. In this paper, we present an analytical framework for vertical soft handoff and propose a context-aware vertical soft handoff algorithm (CAVSH) for heterogeneous wireless networks. CAVSH considers four user and system context parameters such as user required bandwidth, user traffic cost, access network utilization, and signal to interference-and-noise ratio (SINR). The results show that the proposed CAVSH can provide the system with lower dropping probability, lower average cost to the user and higher throughput, as compared with vertical hard handoff.

Next generation heterogeneous wireless networks offer the end users with assurance of QoS inside each access network as well as during vertical handoff between them. For guaranteed QoS, the vertical handoff algorithm must be QoS aware, which cannot be achieved with the use of traditional RSS as the vertical handoff criteria. In this paper, we propose a novel vertical handoff algorithm which uses received SINR from various access networks as the handoff criteria. This algorithm consider the combined effects of SINR from different access networks with SINR value from one network being converted to equivalent SINR value to the target network, so the handoff algorithm can have the knowledge of achievable bandwidths from both access networks to make handoff decisions with QoS consideration. Analytical results confirm that the new SINR based vertical handoff algorithm can consistently offer the end user with maximum available bandwidth during vertical handoff contrary to the RSS based vertical handoff, whose performance differs under different network conditions. System level simulations also reveal the improvement of overall system throughputs using SINR based vertical handoff, comparing with the RSS based vertical handoff.

In the next generation multimedia wireless network environment that consists of heterogeneous access technologies, we need to offer the end user with multimedia QoS inside each access network as well as during vertical handoff between them. The vertical handoff algorithm have to be QoS aware, which cannot be achieved by using the traditional RSS as the vertical handoff criteria. In this paper, we propose a new vertical handoff algorithm using the receiving SINR from various access networks as the handoff criteria. By converting the different receiving SINR values, the handoff algorithm can have the knowledge of achievable bandwidths from both access networks, and make handoff decisions with multimedia QoS consideration. Analysis results confirms that the new SINR based vertical handoff algorithm is able to consistently offer the end user with maximum available bandwidth during vertical handoff comparing with the RSS based vertical handoff, whose performance differs under different network conditions.