To celebrate the 18th Anniversary of Macau University of Science and Technology, the Faculty of Information Technology held a seminar at Block N, Room 221 on 29th Mar,2018. The former president of IEEE(SMC), Daniel S. Yeung, the Associate Dean of the faculty of electrical engineering of Zhejiang University Prof. Qi Donglian，Prof Liang Xiaoyan from Shanghai Institute of Optics and Fine Mechanics and Dr Yang Daquan from Beijing University of Posts and Telecommunications were the invited speaker. Around 50 students and faculty members attended the seminar, including the Dean of the faculty Prof. Zhang Du and the Assistant Dean of the Faculty Prof. Li Jianqing.
Daniel S. Yeung’s topic “Sensitivity-Based Robust Learning Algorithm for Stacked Autoencoder”
Abstract:
Although deep learning has achieved excellent performance in many applications, some studies indicate that deep learning algorithms are vulnerable in an adversarial environment. A small distortion on a sample leads to misclassification easily. Until now, the vulnerability issue of stacked autoencoder, which is one of the most popular deep learning algorithms, has not been investigated. In this talk, a robust learning algorithm which minimizes both its error and sensitivity is proposed for stacked autoencoder. The sensitivity is defined as the change of the output due to a small fluctuation on the input. As the proposed algorithm considers not only accuracy but also stability, a more robust stacked autoencoder against perturbed input is expected. The performance of our methods is then evaluated and compared with conventional stacked autoencoder and denoising autoencoder experimentally in terms of accuracy, robustness and time complexity. Moreover, the experimental results also suggest that the proposed learning method is more robust than others when a training set is contaminated.
Prof. Qi Donglian’s topic “Distributed Estimation and Secondary Control of Autonomous Microgrid”
Abstract:
In many applications such as PV dominated autonomous microgrid, high penetration, geographical dispersion and intermittent nature of PVs have manifested the need for novel control strategies to keep dynamical balance of active power between distributed generators and loads real time and distributively. To this end, this talk focuses on a distributed algorithm to estimate the power difference between generation and consumption, and a finite-time consensus protocol is introduced to regulate the outputs of all the PVs in a cooperative and timely fashion, and the frequency deviation caused by active power unbalance can be compensated as well. In particular, the proposed distributed estimation and secondary control strategy is completely distributed and center-free in the sense that each PV and load are both self-organizing and global-awareness with only local communication, no centralized monitors are needed.
Prof. Liang Xiaoyan’s topic “Development and Applications of High-power Ultra-fast lasers”
Abstract:
High-power Ultra-fast Lasers with pulses duration of ps (10-12 s) and fs (10-15 s) are developed very quickly recently. Recently, he maximum peak power has reached to 10 PW (1015 W) with pulse duration shorter than 30 fs. This kind of lasers was used to research the high intensity physics. Meanwhile, diode pumped high repetition rate ps/fs laser has generated average power of nearly kW, which was applied in science, industry and biomedical.
Dr Yang Daquan’s topic “High sensitivity and high Q-factor photonic crystal cavity sensors”
Abstract:
We experimentally demonstrate a label-free sensor based on nanoslotted parallel quadrabeam photonic crystal cavity (NPQC). The NPQC devices used in this experiment were fabricated from silicon-on-insulator (SOI) with 220nm device layer on a 2μm thick buried oxide layer. The proposed Si-PhC NPQC cavity with the designed parameters: periodicity a=500nm, the nanobeam width b=200nm, the slot width w between adjacent nanobeams w=100nm. It consists of four parallel photonic crystal nanobeam cavities with nano-gap separations. Gratings are in rectangular shape. The widths of the rectangular gratings are kept the same at 140nm. The lengths of the gratings are quadratically tapered from cavity center wcenter=300nm to both sides wside=225nm. The NPQC possesses both high sensitivity and high Q-factor. We achieved sensitivity (S) of 451nm/RIU (refractive index unit) and Q-factor >7000 in water at telecom wavelength range, featuring a sensor figure of merit (FOM) >2000, an order of magnitude improvement over previous photonic crystal sensors. In addition, we measured the streptavidin-biotin binding affinity and detected 10ag/mL concentrated streptavidin in the phosphate buffered saline (PBS) solution.
