336 research outputs found
Xian xing jin na mi bang san jiao zhen lie zhong de ci deng li zi ti
No full textTao, Yuting = 綫性金納米棒三角陣列中的磁等離子體 / 陶煜庭.Thesis M.Phil. Chinese University of Hong Kong 2015.Includes bibliographical references.Abstracts also in Chinese.Title from PDF title page (viewed on 14, November, 2016).Tao, Yuting = Xian xing jin na mi bang san jiao zhen lie zhong de ci deng li zi ti / Tao Yuting
Finite Size Scaling Around One Dimensional Topological Quantum Phase Transitions
No full textUniversity of Minnesota Ph.D. dissertation. May 2020. Major: Physics. Advisors: Alex Kamenev, Rafael Fernandes. 1 computer file (PDF); vi, 81 pages.The critical point of a topological phase transition is described by a conformal field theory. We first investigate the finite-size scaling away from criticality of the ground state energy and find a scaling function, which discriminates between phases with different topological indexes. This function appears to be universal for all five Altland-Zirnbauer symmetry classes with non-trivial topology in one spatial dimension. We obtain an analytic form of the scaling function and compare it with numerical results. Then we verify the universality of the scaling function for the topological transition between dimerized and Haldane phases in bilinear-biquadratic spin-1 chain. To this end we perform high-accuracy variational matrix product state simulations. We show that the scaling function, expressed in terms of , where is the chain length and is the correlation length, coincides with that of three species of non-interacting massive Majorana fermions. The latter is known to be a proper description of the conformal critical theory with central charge . We have shown that it still holds away from the conformal point, including the finite size corrections. Finally we consider scaling of the entanglement entropy across a topological quantum phase transition for the Kitaev chain model. The change of the topology manifests itself in a sub-leading term, which scales as with the size of the subsystem , here is the R\'{e}nyi index. This term reveals the scaling function , where is the correlation length, which is sensitive to the topological index. The scaling function is independent of model parameters, suggesting some degree of its universality.Wang, Yuting. (2020). Finite Size Scaling Around One Dimensional Topological Quantum Phase Transitions. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/215110
Deep Bayesian survival analysis of rail useful lifetime
No full textReliable estimation of rail useful lifetime can provide valuable information for predictive maintenance in railway systems. However, in most cases, lifetime data is incomplete because not all pieces of rail experience failure by the end of the study horizon, a problem known as censoring. Ignoring or otherwise mistreating the censored cases might lead to false conclusions. Survival approach is particularly designed to handle censored data for analysing the expected duration of time until one event occurs, which is rail failure in this paper. This paper proposes a deep Bayesian survival approach named BNN-Surv to properly handle censored data for rail useful lifetime modelling. The proposed BNN-Surv model applies the deep neural network in the survival approach to capture the non-linear relationship between covariates and rail useful lifetime. To consider and quantify uncertainty in the model, Monte Carlo dropout, regarded as the approximate Bayesian inference, is incorporated into the deep neural network to provide the confidence interval of the estimated lifetime. The proposed approach is implemented on a four-year dataset including track geometry monitoring data, track characteristics data, various types of defect data, and maintenance and replacement (M&R) data collected from a section of railway tracks in Australia. Through extensive evaluation, including Concordance index (C-index) and root mean square error (RMSE) for evaluating model performance, as well as a proposed CW-index for evaluating uncertainty estimations, the effectiveness of the proposed approach is confirmed. The results show that, compared with other commonly used models, the proposed approach can achieve the best concordance index (C-index) of 0.80, and the estimated rail useful lifetimes are closer to real lifetimes. In addition, the proposed approach can provide the confidence interval of the estimated lifetime, with a correct coverage of 81% of the actual lifetime when the confidence interval is 1.38, which is more useful than point estimates in decision-making and maintenance planning of railroad systems.Railway Engineerin
Fresh and hardened properties of cement mortars using marble sludge fines and cement sludge fines
No full textThe construction sector could provide solutions for the safe utilization of industrial by-products as construction materials, if proper characterization and control of the materials properties is undertaken. Under this consideration, fines produced from marble cutting and fines produced from concrete truck washing were investigated as fine material for use in cement mortars. Both these by-products are produced in large amounts in the form of sludge. Marble Sludge Fines (MSF) and Cement Sludge Fines (CSF) were characterized in terms of fineness, density, chemical analysis and suitability for use with cement. Mortars with variable rate (10%, 20% and 30%) of cement substitution with MSF or CSF were tested and compared to a reference cement mortar in respect to their fresh and hardened properties. Packing ability and viscosity were measured in fresh mortars, while strength development, water absorption and porosity were measured in hardened mortars. The results confirm the suitability of both as filler material; although MSF performed better regarding fresh mortar properties and CSF showed better results regarding strength development
Strategic leadership in the face of sociopolitical and sociocultural challenges
No full textFirms are living through a period of unprecedented sociopolitical and sociocultural changes. The shifts in external and internal environments increasingly require firms to strategically navigate social challenges not only in their wider societal context, such as cultural conflicts, climate change, and polarization but also within the organizations, including increasing representation diversity within their own boundaries. However, we still lack an integrated understanding of the roles of corporate executives as strategic leaders in navigating such complexity in the environment. In this symposium, we bring together four papers focusing on the different roles of corporate executives (CEOs, CHROs, and TMTs as a whole) in addressing external sociopolitical challenges (e.g., controversial societal issues and activist campaigns) and internal sociocultural complexity (e.g., human resources and national diversity). Do Authentic Activist CEOs Gain Favor from Shareholder Activists? Author: Yuting Yang; Iowa State University CEO Exposure to Diverse Demands from Shareholder Activists and Firm Responses to Subsequent Activism Author: Canquan (Charles) Li; The Hong Kong Polytechnic University Author: Shuping Li; The Hong Kong Polytechnic University Understanding Chief Human Resource Officer Tenures and Activities on Top Management Teams Author: Andrew Millin; Florida International University Author: Donald Joseph Schepker; University of South Carolina The Contrasting Implications of TMT Surface- and Deep-Level National Diversity for Firm Performance Author: Aaron Aujla; London School of Economics and Political Scienc
Silicon micro-pyramid structure for broadband anti-reflection in terahertz frequency
No full textMay 2009School of EngineeringCenter for Terahertz ResearchM
Smooth Sensitivity for Geo-Privacy
No full textSuppose each user i holds a private value xi in some metric space (U, dist), and an untrusted data analyst wishes to compute Íi f (xi) for some function f : U ? R by asking each user to send in a privatized f (xi). This is a fundamental problem in privacy-preserving population analytics, and the local model of differential privacy (LDP) is the predominant model under which the problem has been studied. However, LDP requires any two different xi, xi' to be edistinguishable, which can be overly strong for geometric/numerical data. On the other hand, Geo-Privacy (GP) stipulates that the level of distinguishability be proportional to dist(xi, xi'), providing an attractive alternative notion of personal data privacy in a metric space. However, existing GP mechanisms for this problem, which add a uniform noise to either xi or f (xi), are not satisfactory. In this paper, we generalize the smooth sensitivity framework from Differential Privacy to Geo-Privacy, which allows us to add noise tailored to the hardness of the given instance. We provide definitions, mechanisms, and a generic procedure for computing the smooth sensitivity under GP equipped with a general metric. Then we present three applications: one-way and two-way threshold functions, and Gaussian kernel density estimation, to demonstrate the applicability and utility of our smooth sensitivity framework.</p
Medical Record and Statistical Analysis Office Internship Report2015
No full textinternship report winter 2015This report keeps track of the entire internship that takes place in the medical record
and statistical analysis office of Nanjing Drum Tower Hospital (Nanjing Gulou
Hospital), also known as The Affiliated Hospital of Nanjing University Medical
School.
Tasks performed involves getting familiar with different systems used in reception
desk/ copy and print service, reading room, medical record receiving office, medical
record computerized room, medical record treasury, statistic analysis room; getting
familiar with medical record and computerized process, understanding electronic
medical record; dealing with a large number of medical records sorted by department
and patients’ check out date; working in medical record treasury and statistic analysis
room.
A problem of current medical record receiving process is discussed, and scanning
barcode solution is proposed based on health informatics aspect. In conclusion,
objectives of this internship are basically met at the end of it, include using different
systems, understanding data collecting and processing, experiencing the application of
electronic health record and more. Future works need to focus on team working,
multitasking, and bridging the gap between theory and practice.Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical Schoo
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Optofluidic Sensing from Inkjet-Printed Droplets on Diatom Biosilica
No full textWe explored an optofluidic sensing mechanism from inkjet-printed droplets on diatom biosilica using surface-enhanced Raman scattering (SERS). Our study revealed a new biosensing strategy that combines the microscopic fluidic flow induced by the droplet evaporation and the photonic crystal effects of diatom frustules, which can provide an ultra-sensitive, cost-effective biosensing technology with reduced analyte consumption enormous improvement of detection limit by 106×. Different than the traditional analyte dispensing method using pipette, inkjet printing technology not only minimizes the analyte consumption and prevents coffee rings, but also facilitates significant molecule accumulation on the hydrophilic surface of the diatom frustule during the evaporation process of sub-nanoliter volume droplets, called the evaporation- induced spontaneous flow effect. We achieved single-molecule-level detection of Rhodamine 6G (R6G) and label-free Trinitrotoluene (TNT) sensing at 10-12 M in aqueous solution.Keywords: optofluidics, inkjet printing, fluid dynamics, photonic crystals, localized surface plasmons, surface-enhanced Raman scatterin
The Effects of International Trade on Structural Convergence and CO2 Emissions
No full textThis article introduces a new econometric model that includes an innovative measure of intersectoral structural change. This model describes the structural convergence (or divergence) of sector share patterns across countries (from the North-South or global perspective) influenced by international trade. The econometric analysis applies panel data estimators with different types of fixed effects to the 2013 and 2016 releases of the World Input-Output Database, covering the periods 1995–2009 and 2000–2014. The results show that international trade mostly promotes structural convergence, which is enhanced by sectoral capital intensities. It seems, however, that in this millennium, structural divergence, also fostered by international trade, occurred in terms of the CO2 intensity of production. © 2022, The Author(s)
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