Hong Kong University of Science and Technology

About: Hong Kong University of Science and Technology is a education organization based out in Hong Kong, Hong Kong, China. It is known for research contribution in the topics: Computer science & Catalysis. The organization has 20126 authors who have published 52428 publications receiving 1965915 citations. The organization is also known as: HKUST & The Hong Kong University of Science and Technology.

Power-efficient access-point selection for indoor location estimation

Abstract: An important goal of indoor location estimation systems is to increase the estimation accuracy while reducing the power consumption. In this paper, we present a novel algorithm known as CaDet for power-efficient location estimation by intelligently selecting the number of access points (APs) used for location estimation. We show that by employing machine learning techniques, CaDet is able to use a small subset of the APs in the environment to detect a client's location with high accuracy. CaDet uses a combination of information theory, clustering analysis, and a decision tree algorithm. By collecting data and testing our algorithms in a realistic WLAN environment in the computer science department area of the Hong Kong University of Science and Technology, we show that CaDet (clustering and decision tree-based method) can be much higher in accuracy as compared to other methods. We also show through experiments that, by intelligently selecting APs, we are able to save the power on the client device while achieving the same level of accuracy.

Secret sharing schemes from three classes of linear codes

Abstract: Secret sharing has been a subject of study for over 20 years, and has had a number of real-world applications. There are several approaches to the construction of secret sharing schemes. One of them is based on coding theory. In principle, every linear code can be used to construct secret sharing schemes. But determining the access structure is very hard as this requires the complete characterization of the minimal codewords of the underlying linear code, which is a difficult problem in general. In this paper, a sufficient condition for all nonzero codewords of a linear code to be minimal is derived from exponential sums. Some linear codes whose covering structure can be determined are constructed, and then used to construct secret sharing schemes with nice access structures.

Dimensional Engineering of a Graded 3D–2D Halide Perovskite Interface Enables Ultrahigh Voc Enhanced Stability in the p‐i‐n Photovoltaics

Abstract: 2D halide perovskite materials have shown great advantages in terms of stability when applied in a photovoltaic device. However, the impediment of charge transport within the layered structure drags down the device performance. Here for the first time, a 3D–2D (MAPbI3-PEA2Pb2I4) graded perovskite interface is demonstrated with synergistic advantages. In addition to the significantly improved ambient stability, this graded combination modifies the interface energy level in such a way that reduces interface charge recombination, leading to an ultrahigh Voc at 1.17 V, a record for NiO-based p-i-n photovoltaic devices. Moreover, benefiting from the graded structure induced continuously upshifts energy level, the photovoltaic device attains a high Jsc of 21.80 mA cm−2 and a high fill factor of 0.78, resulting in an overall power conversion efficiency (PCE) of 19.89%. More importantly, it is showed that such a graded interface structure also suppresses ion migration in the device, accounting for its significantly enhanced thermal stability.