Worcester Polytechnic Institute

About: Worcester Polytechnic Institute is a education organization based out in Worcester, Massachusetts, United States. It is known for research contribution in the topics: Computer science & Population. The organization has 6270 authors who have published 12704 publications receiving 332081 citations. The organization is also known as: WPI.

Highly stable and efficient all-inorganic lead-free perovskite solar cells with native-oxide passivation.

Abstract: There has been an urgent need to eliminate toxic lead from the prevailing halide perovskite solar cells (PSCs), but the current lead-free PSCs are still plagued with the critical issues of low efficiency and poor stability. This is primarily due to their inadequate photovoltaic properties and chemical stability. Herein we demonstrate the use of the lead-free, all-inorganic cesium tin-germanium triiodide (CsSn0.5Ge0.5I3) solid-solution perovskite as the light absorber in PSCs, delivering promising efficiency of up to 7.11%. More importantly, these PSCs show very high stability, with less than 10% decay in efficiency after 500 h of continuous operation in N2 atmosphere under one-sun illumination. The key to this striking performance of these PSCs is the formation of a full-coverage, stable native-oxide layer, which fully encapsulates and passivates the perovskite surfaces. The native-oxide passivation approach reported here represents an alternate avenue for boosting the efficiency and stability of lead-free PSCs. Replacing the toxic lead in the state-of-the-art halide perovskite solar cells is highly desired but the device performance and stability are usually compromised. Here Chen et al. develop inorganic cesium tin and germanium mixed-cation perovskites that show high operational stability and efficiency over 7%.

Efficient Adaptive-Support Association Rule Mining for Recommender Systems

Abstract: Collaborative recommender systems allow personalization for e-commerce by exploiting similarities and dissimilarities among customers' preferences We investigate the use of association rule mining as an underlying technology for collaborative recommender systems Association rules have been used with success in other domains However, most currently existing association rule mining algorithms were designed with market basket analysis in mind Such algorithms are inefficient for collaborative recommendation because they mine many rules that are not relevant to a given user Also, it is necessary to specify the minimum support of the mined rules in advance, often leading to either too many or too few ruless this negatively impacts the performance of the overall system We describe a collaborative recommendation technique based on a new algorithm specifically designed to mine association rules for this purpose Our algorithm does not require the minimum support to be specified in advance Rather, a target range is given for the number of rules, and the algorithm adjusts the minimum support for each user in order to obtain a ruleset whose size is in the desired range Rules are mined for a specific target user, reducing the time required for the mining process We employ associations between users as well as associations between items in making recommendations Experimental evaluation of a system based on our algorithm reveals performance that is significantly better than that of traditional correlation-based approaches

An open-source research kit for the da Vinci® Surgical System

Abstract: We present a telerobotics research platform that provides complete access to all levels of control via open- source electronics and software. The electronics employs an FPGA to enable a centralized computation and distributed I/O architecture in which all control computations are implemented in a familiar development environment (Linux PC) and low- latency I/O is performed over an IEEE-1394a (FireWire) bus at speeds up to 400 Mbits/sec. The mechanical components are obtained from retired first-generation da Vinci R Surgical Systems. This system is currently installed at 11 research institutions, with additional installations underway, thereby creating a research community around a common open-source hardware and software platform.