Currently, unsupervised hyperspectral image (HSI) segmentation methods are mainly implemented by clustering. Nevertheless, hyperspectral data contains a large amount of noise during the acquisition process, resulting in an abnormal distribution of many pixel points. Traditional clustering algorithms suffer from inaccurate segmentation when dealing with these data. For example, FCM is sensitive to anomalies in the clustering problem of HSI, that makes the clustering accuracy degraded. To address these problems, this paper proposes a method called Fuzzy C-Multiple-Means (FCMM). The method divides data points with multiple subclusters into defined c clusters. Different from the bottom-up coalescent strategy, the proposed FCMM transforms the problem of merging multiple subclusters into an optimisation problem for the fuzzy affiliation matrix, and updates the partitioning of the q subclusters and c classes by an alternating iterative update method. This enhances the robustness of the algorithm and reduces the effect of outliers in the HSI datasets on the FCMM, which provides superior clustering results. Experiments on several HSI datasets validate the effectiveness of FCMM.

In this work, a physics of failure-based prediction method is combined with statistical models to consider the impact of current crowding and current droop effects on reliability of LED arrays. Electronicthermal models of LEDs are utilized to obtain operation conditions under influences of current crowding and current droop. A Markov chain-based model is used to calculate probability distribution of each failure mode, including the lumen decay and catastrophic failure. Two types of LEDs were selected for a numerical study. The proposed prediction method provides realistic reliability prediction results. It is found that the properties of LEDs have great impact on their hazard rates of LED arrays. The equivalent resistance, 3rd order non-radiative coefficient and radiative coefficient of LEDs are critical to reliability of an LED array.

This brief presents a 73-dB-SNDR 2nd-order noise-shaping successive approximation-register (NS-SAR) analog-to-digital converter (ADC) with a low-noise time-domain comparator. In contrast to most prior works, in which a multi-input voltage-domain comparator was adopted as a signal summation circuit, the proposed NS-SAR employs a time-domain comparator to sum signals, which reduces input-referred noise by increasing the number of voltage-controlled delay stages, exhibiting high noise efficiency. Fabricated in a 65-nm CMOS process, the prototype 6-bit NS-SAR ADC achieves a peak signal-to-noise and distortion ratio (SNDR) of 73 dB over a bandwidth of 250kHz with an oversampling ratio (OSR) of 20, while consuming only 93.85 úW from a 1 V supply, leading to an SNDR-based Schreier figure of merit (FoM) of 167.3 dB.

The development of integrated circuits has increased the size of chip interconnects, which has brought challenges to interconnect design in chip packages. The closer the spacing between interconnects, the higher the space utilization, which can cause severe crosstalk problems in high-speed circuits. In this paper, we applied delay-insensitive coding to the design of high-speed package interconnects. We also analyzed the effect of delay-insensitive coding on crosstalk improvement in package interconnects at 26 GHz for its high crosstalk immunity. Compared to the synchronous transmission circuit, the 1-of-2 and 1-of-4 encoded circuits designed in this paper can reduce crosstalk peaks by 22.9% and 17.5% on average at a wiring spacing of 1–7 μm, which can achieve closer wiring spacing.

In this paper, effect of the input current frequency on the reliability of LEDs is investigated experimentally. A type of common-used white light LED is selected as test samples. LED aging tests were conducted by using inputs with different frequencies. Meanwhile, to avoid measurement errors in the long-term test, a group of LEDs without aging are tested as well. During the aging process, LEDs' I-V curves and luminous output at different time points were measured. Then, via parameter fitting, degradations of key parameters along aging duration, such as the saturation current, Ideal Factor, equivalent series resistance, luminous efficacy, can be extracted. By analyzing the degradations of key parameters in different conditions, impacts of the input current frequency on LEDs' reliability can be determined. It has found that the AC input with half-wave rectification may have significant impact on reliability of LEDs' interconnections inside packages. The results of the conventional method will only match the reality when the frequency exceeds a specific value. The AC inputs with half-wave rectification have limited impacts on LED chips. It is difficult to simulate all actual usage conditions with conventional DC aging methods. Therefore, it is necessary to use AC inputs with similar frequency as practical applications in reliability assessments of LED packages.