Browsing by Author "Yu, Qi"

Now showing 1 - 3 of 3
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    Follow My Steps
    Siddiqui, Haris; Lee, Wen-Yu; Wang, Yifu; Yu, Qi (2022-05-04)
    Follow My Steps is a unique Android mobile application that allows users to track celebrities’ footsteps and stories. Although many travel apps already exist on the market, our product addresses problems that others don’t. For example, our app is inspiration-oriented and not a tool-based service. The app gives your trip an interesting and meaningful theme. It allows users to plan their trips by following their favorite celebrities’ steps. Users can receive inspiration from the places celebrities visit.
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    A Foundational Framework for Service Query Optimization
    Yu, Qi (Virginia Tech, 2008-07-30)
    In this dissertation, we present a novel foundational framework that lays out a theoretical underpinning for the emerging services science. The proposed framework provides disciplined and systematic support for efficient access to Web services' functionalities. The key components of the proposed framework centers around a novel service model that provides a formal abstraction of the Web services within an application domain. A service calculus and a service algebra are defined to facilitate users in accessing services via declarative service queries. We provide the implementation of the service algebra. This enables the generation of Service Execution Plans (SEPs) that can be used by users to directly access services. We present an optimization algorithm to efficiently select the SEPs with the best QoWS. We then propose a multi-objective optimization approach that releases users from the tedious weight assigning process. We develop service skyline computation techniques that return a set of most interesting SEPs. The service skyline guarantees to include the user desired SEPs. We further explore a set of novel heuristics for computing service skylines over sets of services. This enables users to efficiently and optimally access multiple services simultaneously as an integrated service package. Finally, we consider the performance fluctuation of service providers due to the dynamic service environment. We propose an uncertain QoWS model and a novel concept called p-dominant service skyline. We develop new indexing structures and algorithms to efficiently compute the p-dominant service skyline. We derive analytical models and conduct extensive sets of experiments to evaluate the proposed framework and service query optimization algorithms.
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    Occurrence of Free Amino Acids in the Source Waters of Zhejiang Province, China, and Their Removal and Transformation in Drinking Water Systems
    Yang, Yulong; Yu, Qi; Zhou, Ruonan; Feng, Jiao; Zhang, Kejia; Li, Xueyan; Ma, Xiaoyan; Dietrich, Andrea M. (MDPI, 2019-12-24)
    Free amino acids (FAAs) are key components of the global nitrogen cycle and important disinfection byproduct (DBP) precursors. The knowledge gap of FAA occurrence in source and engineered water is discussed in this paper. Solid phase extraction and post column derivatization was combined with gas chromatography–mass spectrometry to simultaneously detect μg/L concentrations of FAAs. This method efficiently detects alanine (Ala), threonine (Thr), serine (Ser), valine (Val), leucine (Leu), isoleucine (Ile), proline (Pro), aspartic (Asp), phenylalanine (Phe), and glutamic acid (Glu) with good linearity, accuracy, and precision. An investigation of FAAs in surface waters in Zhejiang Province found concentrations of 1.48–14.73 μg/L Ala, 0.20–2.39 μg/L Thr, 0.41–7.84 μg/L Val, 0.21–6.86 μg/L Ser, 0.11–4.16 μ;g/L Leu, 0.57–1.54 μg/L Ile, 0.24–8.06 μg/L Pro, 0.42–4.73 μg/L Asp, 0.30–3.01 μg/L Phe, and 0.12–3.83 μg/L Glu. Phe and tyrosine (Tyr) exhibited higher trichloromethane (TCM) formation (1029–1148 μg/mmolAA) than dichloroacetonitrile (DCAN) formation (333–347 μg/mmolAA). Asp and Glu demonstrated the opposite trend: higher DCAN (570–1106 μg/mmolAA) formation than TCM (137–506 μg/mmolAA).