Effective pattern discovery for text mining

Many data mining techniques have been proposed for mining useful patterns in text documents. However, how to effectively use and update discovered patterns is still an open research issue, especially in the domain of text mining. Since most existing text mining methods adopted term-based approaches, they all suffer from the problems of polysemy and synonymy. Over the years, people have often held the hypothesis that pattern (or phrase) based approaches should perform better than the term-based ones, but many experiments did not support this hypothesis. This paper presents an innovative technique, effective pattern discovery which includes the processes of pattern deploying and pattern evolving, to improve the effectiveness of using and updating discovered patterns for finding relevant and interesting information. Substantial experiments on RCV1 data collection and TREC topics demonstrate that the proposed solution achieves encouraging performance

Novel Broadband Amplifier for Mid-Infrared Semiconductor laser and applications in spectroscopy

An amplifier design for broadband Mid-IR buried-hetero (BH) structure epitaxial laser is presented, and external cavity design based on this amplifier is described. Spectroscopy results characterizing such single frequency lasers are demonstrated with whispering gallery mode CaF2 disc/ball, saturated absorption in hollow waveguide and direct chemical analysis in water

Applications of quantum cascade lasers in chemical sensing

We show new results in modulating and modifying Quantum Cascade (QC) lasers to make them more suitable for chemical sensing spectroscopy. Spectroscopy results using QC lasers are demonstrated with whispering gallery mode CaF_2 disc/ball, saturated absorption in hollow waveguide and direct chemical analysis in water

Quantum cascade laser sensors for online gas chromatography

We show that QC laser could improve capillary Gas Chromatography Infrared spectroscopy resolution significantly, i.e. both Doppler limited and Doppler free resolution could be achieved. To achieve these goals, we report our latest efforts in characterizing the tuning and noise properties of Quantum Cascade (QC) lasers; novel schemes on modulation to gain largest tuning range as well as on stabilizing and locking the QC lasers are proposed, and results presented

Microsensors based on quantum cascade lasers

We present our results on efficient coupling of Quantum Cascade Lasers (QCLs) into Whispering Gallery Resonators, Hollow Waveguide. We also present results of micro sensors using the unique properties of QCLs, e.g. online sensors for Gas Chromatography (GC). We show that because of the unique brightness properties of QCLs, we could improve GC-Infrared sensors' sensitivity to the same level as Mass Spectrometry, and with different dimension of chemical information

HDIdx: High-Dimensional Indexing for Efficient Approximate Nearest Neighbor Search

Fast Nearest Neighbor (NN) search is a fundamental challenge in large-scale data processing and analytics, particularly for analyzing multimedia contents which are often of high dimensionality. Instead of using exact NN search, extensive research efforts have been focusing on approximate NN search algorithms. In this work, we present "HDIdx", an efficient high-dimensional indexing library for fast approximate NN search, which is open-source and written in Python. It offers a family of state-of-the-art algorithms that convert input high-dimensional vectors into compact binary codes, making them very efficient and scalable for NN search with very low space complexity