Design and Robustness Analysis on Non-volatile Storage and Logic Circuit

By combining the flexibility of MOS logic and the non-volatility of spintronic devices, spin-MOS logic and storage circuitry offer a promising approach to implement highly integrated, power-efficient, and nonvolatile computing and storage systems. Besides the persistent errors due to process variations, however, the functional correctness of Spin-MOS circuitry suffers from additional non-persistent errors that are incurred by the randomness of spintronic device operations, i.e., thermal fluctuations. This work quantitatively investigates the impact of thermal fluctuations on the operations of two typical Spin-MOS circuitry: one transistor and one magnetic tunnel junction (1T1J) spin-transfer torque random access memory (STT-RAM) cell and a nonvolatile latch design. A new nonvolatile latch design is proposed based on magnetic tunneling junction (MTJ) devices. In the standby mode, the latched data can be retained in the MTJs without consuming any power. Two types of operation errors can occur, namely, persistent and non-persistent errors. These are quantitatively analyzed by including models for process variations and thermal fluctuations during the read and write operations. A mixture importance sampling methodology is applied to enable yield-driven design and extend its application beyond memories to peripheral circuits and logic blocks. Several possible design techniques to reduce thermal induced non-persistent error rate are also discussed

How Does the Low-Rank Matrix Decomposition Help Internal and External Learnings for Super-Resolution

Wisely utilizing the internal and external learning methods is a new challenge in super-resolution problem. To address this issue, we analyze the attributes of two methodologies and find two observations of their recovered details: 1) they are complementary in both feature space and image plane, 2) they distribute sparsely in the spatial space. These inspire us to propose a low-rank solution which effectively integrates two learning methods and then achieves a superior result. To fit this solution, the internal learning method and the external learning method are tailored to produce multiple preliminary results. Our theoretical analysis and experiment prove that the proposed low-rank solution does not require massive inputs to guarantee the performance, and thereby simplifying the design of two learning methods for the solution. Intensive experiments show the proposed solution improves the single learning method in both qualitative and quantitative assessments. Surprisingly, it shows more superior capability on noisy images and outperforms state-of-the-art methods

A Multi-Robot System Based on A Hybrid Communication Approach

Communication plays an important role in a multi-robot system. In a large system with many robots, it is difficult for all robots to exchange information at a time because of their limited communication capacities. On the other hand, sometimes there is such a situation where no explicit communication is allowed between robots. Therefore, efficient and reliable communication together with non-explicit communication is crucial for a multi-robot system. This paper presents a hybrid communication approach for a multi-robot system, which combines the explicit with implicit communications via using the prediction of robotic behaviour and a fuzzy communication approach. The hybrid communication approach contains a robot performance rule base, a fuzzy inference engine, and a semantics and grammar for communicating. Based on the hybrid communication strategy, the avoidance of collision with multiple robots in working area and multiple robots transporting a common object have been explored. The results of simulation show that the multi-robot system can complete a cooperative task successfully

A correction method of encoder bias in satellite laser ranging system

Abstract:In a satellite laser ranging telescope system, well-aligned encoders of the elevation and azimuth axes are essential for tracking objects. However, it is very difficult and time-consuming to correct the bias between the absolute-position indices of the encoders and the astronomical coordinates, especially in the absence of a finder scope for our system. To solve this problem, a method is presented based on the phenomenon that all stars move anti-clockwise around Polaris in the northern hemisphere. Tests of the proposed adjustment procedure in a satellite laser ranging (SLR) system demonstrated the effectiveness and the time saved by using the approach, which greatly facilitates the optimization of a tracking system

Densifying Hydration Products of Alite by a Bio-Inspired Admixture

A bio-inspired, plant-derived polyphenol, tannic acid (TA) was identified as a renewable admixture to improve the compressive strength of concretes. Aiming to understand the underlying mechanism responsible for this strength improvement, this study examines how TA mediates the hydration of tricalcium silicate (alite). Experimental study shows that TA can form complex with calcium ions through chelating, retarding the hydration of the alite and changing of the hydration products. Particularly, X-ray diffraction analysis shows that TA makes calcium hydroxide preferentially grow on the [0 0 1] face. Fourier-transform infrared spectroscopy and 29Si MAS NMR results reveal that the mean chain length of calcium silicate hydrate (C[sbnd]S[sbnd]H) is reduced by TA. More importantly, mercury intrusion porosimetry testing reveals that pores with size near 30 nm was almost eliminated by adding TA, leading to higher elastic modulus of the produced C[sbnd]S[sbnd]H and higher compressive strength of the produced concrete

Progress of the satellite laser ranging system TROS1000

AbstractThe mobile satellite laser ranging system TROS1000, successfully developed in 2010, achieves a high repetition rate and enables daytime laser ranging. Its measurement range has reached up to 36000 km with an accuracy as precise as 1 cm. Using recent observations in Wuhan, Jiufeng, Xianning, and Rongcheng, Shandong, we introduce the progress made using this mobile observation system

Surface Adjustment Strategy for a Large Radio Telescope with Adjustable Dual Reflectors

With the development of large-aperture and high-frequency radio telescopes, a surface adjustment procedure for the compensation of surface deformations has become of great importance. In this study, an innovative surface adjustment strategy is proposed to achieve an automated adjustment for the large radio telescope with adjustable dual reflectors. In the proposed strategy, a high-precision and long-distance measurement instrument is adopted and installed on the back of the sub-reflector to measure the distances and elevation angles of the target points on the main reflector. Here, two surface adjustment purposes are discussed. The first purpose is to ensure that the main reflector and sub-reflector are always positioned at their ideal locations during operation. The second purpose is to adjust the main reflector to the location of the best fitting reflector, and the sub-reflector to the focus of the best fitting reflector. Next, the calculation procedures for the adjustments of the main reflector and the sub-reflector are discussed in detail, and corresponding simulations are carried out to verify the proposed method. The results show that the proposed strategy is effective. This study can provide helpful guidance for the design of automated surface adjustments for large telescopes

Effect of Temperature on Electromagnetic Performance of Active Phased Array Antenna

Active phased array antennas (APAAs) can suffer from the effects of harsh thermal environments, which are caused by the large quantity of power generated by densely packed T/R modules and external thermal impacts. The situation may be worse in the case of limited room and severe thermal loads, due to heat radiation and a low temperature sink. The temperature field of the antenna can be changed. Since large numbers of temperature-sensitive electronic components exist in T/R modules, excitation current output can be significantly affected and the electromagnetic performance of APAAs can be seriously degraded. However, due to a lack of quantitative analysis, it is difficult to directly estimate the effect of temperature on the electromagnetic performance of APAAs. Therefore, this study investigated the electromagnetic performance of APAAs as affected by two key factors—the uniformly distributed temperature field and the temperature gradient field—based on different antenna shapes and sizes, to provide theoretical guidance for their thermal design