At present, drone delivery systems usually function only in global positioning system (GPS)-friendly environments and thus cannot deliver goods into customers’ houses, which is an element of urban last-mile delivery. In this study, we investigated solutions for enabling drones to fly autonomously in mixed indoor–outdoor environments. We propose a novel Internet of Things (IoT)-based drone delivery system, namely DroneTalk, for mail delivery. DroneTalk combines a GPS, an inertial measurement unit, and visual information to achieve mixed indoor–outdoor autopilot operation. Furthermore, DroneTalk integrates an autonomous drone control system with an IoT device management platform to enable a drone to achieve automatic online weather awareness. Most importantly, DroneTalk is a novel work considering communication, processing, and control latencies simultaneously during autopilot operation to avoid problems related to drone collisions. These problems have always existed but become more serious when drones are flying close to buildings. Simulation results indicate that the proposed system can attain a high user-defined flight success rate (i.e., 99% in our simulations) without any collisions; thus, the proposed system can be feasibly used in real-world environments.

This study provides the experience of applying an advanced version of our former Spurious Power Suppression Technique (SPST) on multipliers for high-speed and low-power purposes. To filter out the useless switching power, there are two approaches, i.e. using registers and usingANDgates, to assert the data signals of multipliers after the data transition. The simulation results show that the SPST implementation withANDgates owns an extremely high flexibility on adjusting the data asserting time which not only facilitates the robustness of SPST but also leads to a 40% speed improvement. By adopting a 0.18-μm CMOS technology, the proposed SPST-equipped multiplier dissipates only 0.0121 mW per MHz in H.264texture coding applications, and obtains a 40% power reduction.

This paper proposes an area-efficient variable length decoder (VLD) IP core design for MPEG-$hbox 1/2/4$video coding applications. The proposed IP core exploits the parallel numerical matching in the MPEG-$hbox 1/2/4$entropy decoding to achieve high data throughput rate in terms of limited hardware cost. This feature not only improves the performance of VLD, but also facilitates reducing the power consumption through lowering down the supply voltage while maintaining enough data throughput rate. Moreover, we propose a partial combinational component enabling approach for minimizing the power consumption of the proposed design. Based on 0.18-$mu$m CMOS technology, the implementation results show that the proposed IP core operates at 125-MHz clock frequency with the cost of 13 105 gates. In addition, the power consumption of the proposed design reaches 163.4$mu$W operated at 12.5 MHz with 0.9-V supply voltage, which is fast enough for MPEG-1/2/4 real-time decoding on 4CIF video@30 Hz. Compared to the existing designs, the proposed IP core possesses both higher data throughput and less hardware cost.

The camera imaging system has been widely used; however, the displaying image appears to have an unequal light distribution. This paper presents novel light-balancing techniques to compensate uneven illumination based on adaptive signal processing. For text image processing, first, we estimate the background level and then process each pixel with nonuniform gain. This algorithm can balance the light distribution while keeping a high contrast in the image. For graph image processing, the adaptive section control using piecewise nonlinear gain is proposed to equalize the histogram. Simulations show that the performance of light balance is better than the other methods. Moreover, we employ line-based processing to efficiently reduce the memory requirement and the computational cost to make it applicable in real-time systems.

The stability conditions for Takagi-Sugeno fuzzy systems suggested in the above mentioned article by Lo-Chen (ibid. vol.7 (1999)) are shown by a counterexample not to be sufficient. In reply, Lo-Chen point out that the example also indicates the fuzzy stability problem is related to the premise part of fuzzy rules.

The main objective of this research is to provide a systematic stability analysis technique for fuzzy systems using well-established results from robust stability of a family of polynomials. The model-based Takagi-Sugeno (1985) fuzzy control system is considered and shown to have a dependent coefficient structure involving firing strengths. Two Kharitonov regions via overbounding are established to facilitate the extreme results for stability test in the space of polynomials as well as the complex plane. The criterion obtained is a sufficient condition for a fuzzy logic controller. Three nonlinear examples are demonstrated to show that the systematic approach proposed here can be used to solve fuzzy stability problems. Fuzzy users concerned over stability issues may find these analytic tools useful.