With the increasing number of I/O pins in highly integrated semiconductor products, semiconductor packaging has become an essential yet complex part of integrated circuit (IC) design. The substrate plays an important role in advanced semiconductor packaging and provides the chip with electrical connections and heat dissipation. While numerous studies have addressed the substrate routing problem, only one state-of-the-art work provides a customized routing flow specifically designed for packages with wire-bonding style and fine-pitch ball grid arrays (FBGA), which are more widely used than advanced packaging due to their maturity and lower cost. However, the existing router suffers from unsatisfactory routability due to its simplistic implementation and lack of necessary consideration for finger connections. Therefore, this paper proposes several optimization heuristics, such as finger accessibility enhancement, progressive rerouting, and half-grid rerouting techniques, to further improve the overall routing completion rate. Experimental results show that the proposed heuristics are capable of avoiding routing resource wastage, achieving better routing quality, and eliminating design-rule violations.

In this paper, a new switched-mode bidirectional bridgeless AC/DC converter, operating in the discontinuous conduction mode (DCM), for automotive energy harvesting is presented. The simple topology consisting of common source n-MOSFETs allows for direct AC/DC conversion, minimum auxiliary circuits and simple gating patterns, when compared to other AC/DC converters proposed in the literatures. The circuit operation is analyzed and shown that the converter-battery topology can operate as a synthesized variable resistor with regenerative functionality. The circuit is designed for low-power energy harvesting applications; for example, regenerating dissipated power in a vehicle suspension damper by converting vibrational energy into battery charge. Simulation results including various switching waveforms and power conversion efficiency are presented to demonstrate performance of the proposed converter. Experimental results, including power conversion efficiency and resistance synthesis sweep, by connecting the proposed converter to a regenerative vehicle suspension prototype are also included.

This paper proposes a mechatronic suspension system with capabilities of energy regeneration and sky- hook (SK) control incorporated into the mechanism. The system overcomes the tradeoffs between energy consumption and ride comfort in an active suspension system. Central to the concept is development of a coupled switched-mode rectifier (SMR) capable of providing either a positive or negative damping ratio by alternating between regenerative and motoring modes. Using the proposed circuit, an active sky-hook control strategy is utilized to offer continuous damping force that improves the vibration isolation significantly. Simulation results presented demonstrate the directions of power flow in both regenerating and motoring modes to verify performance of the SMR.

This paper considers the target patrolling problem which asks a set of mobile data mules to efficiently patrol a set of given targets. Since the time interval (also referred to visiting interval) for consecutively visiting to each target reflects the monitoring quality of this target, the goal of this research is to minimize the maximal visiting interval. This paper firstly proposes a basic algorithm, called Basic (B-TCTP), which aims at constructing an efficient patrolling route for a number of given data mules such that the visiting intervals of all target points can be minimized. For the scenario containing weighted target points, a Weighted-TCTP (W-TCTP) algorithm is further proposed to satisfy the demand that targets with higher weights have higher data collection frequencies. By considering the energy constraint of each data mule, this paper additionally proposes a RW-TCTP algorithm which treats energy recharge station as a weighted target and arranges the data mules visiting the recharge station before exhausting their energies. Performance study demonstrates that the proposed algorithms outperform existing approaches in terms of visiting intervals of the given targets and length of patrolling path.

In wireless sensor networks (WSNs), the performance of robot deployment is highly determined by the obstacle-resistance capability which refers to how well the robot can overcome the Dead-End problem and deploy minimal number of sensors for achieving full coverage even though the environment contains multiple obstacles. This paper presents a Dead-End free robot deployment algorithm, called DFD, that efficiently deploys minimal number of sensors for achieving full coverage while the Dead-End problem raised by obstacles can be overcome. Performance results reveal that the proposed DFD outperforms existing robot deployment mechanisms in terms of coverage ratio, energy consumption as well as deployment time.