Axiomatic Analysis of Unsupervised Diversity on Large-Scale High-dimensional Data

Diversity is a concept widely used in every corner of our society. It represents the "breadth" of a set of objects, which needs to be promoted or reduced in different scenarios. Though many people have discussed it, how to define diversity in a reliable way is still a non-trivial task. In particular, when we are facing large-scale high-dimensional data, it is impossible to use pre-defined classifications to divide each object into categories and utilize diversity measurements in downstream tasks. An unsupervised methodology is necessary to handle this challenge. In this dissertation, I explore different methods to address the research question: how to measure diversity in an unsupervised manner based on large-scale high-dimensional data. I leverage representation learning algorithms to project objects into a discrete or continuous space and design several metrics to measure diversity in real-world applications. Furthermore, I introduce an axiomatic analysis method to help us choose and evaluate diversity metrics in both discrete and continuous settings. Following the guidelines derived from the axiomatic analysis, I define diversity in terms of metrics to map distributions of topics to real numbers in discrete space. I also find a simple and intuitive metric to measure diversity, which is defined in continuous space, that performs surprisingly well to satisfy different axioms. The sound and reliable metrics motivate me to focus on some controversial research topics in real applications. I explore the effect of research diversity i.e., how broad researchers' research interests are. I conduct several studies to figure out whether publishing papers with high diversity results in greater research impact. Furthermore, I track trajectories of researchers' careers and try to find the effects of research diversity at different stages. Another real-world application appears in online social networks. Structural diversity, the closeness of users' friends, has a substantial influence on users' behavior from many perspectives. I define users' structural diversity using the results of axiomatic analysis. I track the pattern within the variation in structural diversity in both static and dynamic networks and simulate it with an intuitive graph generation algorithm. An interesting pattern of structural diversity and user engagement in online social media is illustrated.PHDInformationUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/169733/1/shiyansi_1.pd

Mapping the temporal evolution of scientific community structures

We present results from tracking the temporal evolution of community structures within a research specialty. This extends our previous work in which we generated static community maps that combine co‐author networks and direct citation networks derived from 20‐years of publications in the research specialty. Here, we explore how the temporal evolution of these maps can be used to provide insights into the historical evolution of a field as well as extract more accurate snapshots of the community structures at a given point in time. Such time resolved mappings are an important component in our mixed method approach that integrates network analysis with ethnographic field studies to investigate field‐specific communication and collaboration behaviors in scientific communities (Velden & Lagoze 2013). Evaluating these maps in qualitative interviews with field experts will be the next step in our research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111255/1/meet14505101143.pd

Understanding the Relationship between Scholars' Breadth of Research and Scientific Impact

Many existing metrics to evaluate scholars only concern their scientific impact and omit the importance of breadth of research. In this poster, we define a new metric for breadth of research based on the generalized Stirling metric which considers many aspects of breadth of research and satisfies several axioms for breadth of metrics. Also experiments on the ACM dataset show weak correlation between breadth of research measured by our new metric and scientific impact. And the variation of our metric over time illustrates a possible publication pattern for scholars.ye

Different Levels in Orexin Concentrations and Risk Factors Associated with Higher Orexin Levels: Comparison between Detoxified Opiate and Methamphetamine Addicts in 5 Chinese Cities

This study sought to explore the degree of orexin levels in Chinese opiate and methamphetamine addicts and the differences between them. The cross-sectional study was conducted among detoxified drug addicts from Mandatory Detoxification Center (MDC) in five Chinese cities. Orexin levels were assayed with radioimmunoassay (RIA). Mann-Whitney test and Kruskal-Wallis test were used to detect differences across groups, and logistic regression was used to explore the association between orexin levels and characteristics of demographic and drug abuse. Between November 2009 and January 2011, 285 opiates addicts, 112 methamphetamine addicts, and 79 healthy controls were enrolled. At drug withdrawal period, both opiate and methamphetamine addicts had lower median orexin levels than controls, and median orexin levels in opiate addicts were higher than those in methamphetamine addicts (all above < 0.05). Adjusted odds of the above median concentration of orexin were higher for injection than "chasing the dragon" (AOR = 3.1, 95% CI = 1.2-7.9). No significant factors associated with orexin levels of methamphetamine addicts were found. Development of intervention method on orexin system by different administration routes especially for injected opiate addicts at detoxification phase may be significant and was welcome

Investigation into the Influence of Physician for Treatment Based on Syndrome Differentiation

Background. The characteristics of treatment based on syndrome differentiation (TBSD) cause great challenges to evaluate the effectiveness of the clinical methods. Objectives. This paper aims to evaluate the influence of physician to personalized medicine in the process of TBSD. Methods. We performed a randomized, triple-blind trial involving patients of primary insomnia treated by 3 physicians individually and independently. The patients (n=30) were randomly assigned to receive treatments by the 3 physicians for every visit. However, they always received the treatment, respectively, prescribed by the physician at the first visit. The primary outcome was evaluated, respectively, by the Pittsburgh Sleep Quality Index (PSQI) and the TCM symptoms measuring scale. The clinical practices of the physicians were recorded at every visit including diagnostic information, syndrome differentiation, treating principles, and prescriptions. Results. All patients in the 3 groups (30 patients) showed significant improvements (>66%) according to the PSQI and TCM symptoms measuring scale. Conclusion. The results indicate that although with comparable effectiveness, there exist significant differences in syndrome differentiation, the treating principles, and the prescriptions of the approaches used by the 3 physicians. This means that the physician should be considered as an important factor for individualized medicine and the related TCM clinical research

An Optical AC Voltage Sensor Based on the Transverse Pockels Effect

This paper introduces an optical AC voltage sensor based on the transverse Pockels effect. The sensor utilizes a bulk Bi4Ge3O12 (BGO) crystal as the sensing element. The measurement principle has been described and prototype of the sensor has been constructed and evaluated. Good linearity and accuracy performance was obtained for AC voltage measurement. The proposed sensor can be thus applied to high AC voltage measurements in the electric power industry

Sex Differences and Psychological Stress: Responses to the COVID-19 Pandemic in China

BACKGROUND: About 83,000 COVID-19 patients were confirmed in China up to May 2020. Amid the well-documented threats to physical health, the effects of this public health crisis - and the varied efforts to contain its spread - have altered individuals\u27 normal daily functioning. These impacts on social, psychological, and emotional well-being remain relatively unexplored - in particular, the ways in which Chinese men and women experience and respond to potential behavioral stressors. Our study investigated sex differences in psychological stress, emotional reactions, and behavioral responses to COVID-19 and related threats among Chinese residents. METHODS: In late February (2020), an anonymous online questionnaire was disseminated via WeChat, a popular social media platform in China. The cross-sectional study utilized a non-probabilistic snowball or convenience sampling of residents from various provinces and regions of China. Basic demographic characteristics (e.g., age and gender) - along with residential living arrangements and conditions - were measured along with psychological stress and emotional responses to the COVID-19 pandemic. RESULTS: Three thousand eighty-eight questionnaires were returned: 1749 females (56.6%) and 1339 males (43.4%). The mean stress level,as measured by a visual analog scale, was 3.4 (SD = 2.4) - but differed significantly by sex. Besides sex, factors positively associated with stress included: age (\u3c 45 years), employment (unsteady income, unemployed), risk of infection (exposureto COVID-19, completed medical observation), difficulties encountered (diseases, work/study, financial, mental), and related behaviors (higher desire for COVID-19 knowledge, more time concerning on the COVID-19 outbreak). Protective factors included frequent contact with colleagues, calmness of mood comparing with the pre-pandemic, and psychological resilience. Males and females also differed significantly in adapting to current living/working, conditions, responding to run a fever, and needing psychological support services. CONCLUSIONS: The self-reported stress of Chinese residents related to the COVID-19 pandemic was significantly related to sex, age, employment, resilience and coping styles. Future responses to such public health threats may wish to provide sex- and/or age-appropriate supports for psychological health and emotional well-being to those at greatest risk of experiencing stress