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arXiv 2019年

作者： Magallanes, Jessica Van Gemeren, Lindsey Wood, Steven Villa-Uriol, Maria-Cruz Department of Computer Science INSIGNEO Institute for in silico Medicine University of Sheffield Sheffield United Kingdom Sheffield Teaching Hospitals NHS Foundation Trust INSIGNEO Institute for in silico Medicine University of Sheffield Sheffield United Kingdom

Event data is present in a variety of domains such as electronic health records, daily living activities and web clickstream records. Current visualization methods to explore event data focus on discovering sequential patterns but present limitations when studying time attributes in event sequences. Time attributes are especially important when studying waiting times or lengths of visit in patient flow analysis. We propose a visual analytics methodology that allows the identification of trends and outliers in respect of duration and time of occurrence in event sequences. The proposed method presents event data using a single Sequential and Time Patterns overview. User-driven alignment by multiple events, sorting by sequence similarity and a novel visual encoding of events allows the comparison of time trends across and within sequences. The proposed visualization allows the derivation of findings that otherwise could not be obtained using traditional visualizations. The proposed methodology has been applied to a real-world dataset provided by Sheffield teaching Hospitals NHS Foundation Trust, for which four classes of conclusions were derived. Copyright © 2019, The Authors. All rights reserved.

关键词： Visualization

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Causal inference in survival analysis using longitudinal observational data: Sequential trials and marginal structural models

arXiv

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arXiv 2021年

作者： Keogh, Ruth H. Gran, Jon Michael Seaman, Shaun R. Davies, Gwyneth Vansteelandt, Stijn Department of Medical Statistics Centre for Statistical Methodology London School of Hygiene & Tropical Medicine Keppel Street LondonWC1E 7HT United Kingdom Oslo Centre for Biostatistics and Epidemiology Department of Biostatistics Institute of Basic Medical Sciences University of Oslo P.O. Box 1122 Blindern Oslo0317 Norway MRC Biostatistics Unit University of Cambridge Institute of Public Health Forvie Site Robinson Way CambridgeCB2 0SR United Kingdom Population Policy and Practice Research and Teaching Department Great Ormond Street Institute of Child Health University College London LondonWC1N 1EH United Kingdom Department of Applied Mathematics Computer Science and Statistics Ghent University Ghent9000 Belgium

Longitudinal observational patient data can be used to investigate the causal effects of time-varying treatments on time-to-event outcomes. Several methods have been developed for controlling for the time-dependent confounding that typically occurs. The most commonly used is inverse probability weighted estimation of marginal structural models (MSM-IPTW). An alternative, the sequential trials approach, is increasingly popular, in particular in combination with the target trial emulation framework. This approach involves creating a sequence of 'trials' from new time origins, restricting to individuals as yet untreated and meeting other eligibility criteria, and comparing treatment initiators and non-initiators. Individuals are censored when they deviate from their treatment status at the start of each 'trial' (initiator/non-initiator) and this is addressed using inverse probability of censoring weights. The analysis is based on data combined across trials. We show that the sequential trials approach can estimate the parameter of a particular MSM, and compare it to a MSM-IPTW with respect to the estimands being identified, the assumptions needed and how data are used differently. We show how both approaches can estimate the same marginal risk differences. The two approaches are compared using a simulation study. The sequential trials approach, which tends to involve less extreme weights than MSM-IPTW, results in greater efficiency for estimating the marginal risk difference at most follow-up times, but this can, in certain scenarios, be reversed at late time points. We apply the methods to longitudinal observational data from the UK Cystic Fibrosis Registry to estimate the effect of dornase alfa on survival. © 2021, CC BY.

关键词： Hospital data processing

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An academic emotion database and the baseline evaluation 13

An academic emotion database and the baseline evaluation

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13th International Conference on computer science and Education, ICCSE 2018

作者： Bian, Cunling Zhang, Ya Wang, Deliang Liang, Yi Wu, Bo Lu, Weigang Ocean University of China Department of Educational Technology Qingdao China Ocean University of China Teaching Center of Fundamental Courses Qingdao China Department of Computer Science and Technology Ocean University of China Qingdao China

ISBN: (纸本)9781538654958

Academic emotion is one of the important factors affecting learning effect, which exists on various learning situations. Realizing its automatical inference has a significant meaning for educational field. Facial expression recognition (FER) is always selected as its basis. Nevertheless, the preconditions for FER include a high quality database with sufficient training samples, which is not available currently. In this paper, the previously developed facial expression databases are reviewed and a novel database is established. It includes spontaneous facial expressions of five common academic emotions. 30,184 images from 82 students are included, which are collected in a real online learning environment. Both participants themselves and trained coders are invited to label the samples. The reliability of the encoding is validated by Fleiss's kappa 0.867 and Cohen's kappa 0.943, which is good. For baseline evaluation, two kinds of recognition algorithms are employed with 10-fold cross-validation over participants. One is the combination of different feature extraction technologies and classifiers and the other is Convolution Neural Network (CNN). The best result is obtained by CNN with 0.877 accuracy. Such a database will certainly accelerate the application of affective computing in educational field. © 2018 IEEE.

关键词： Database systems

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Rare event simulation for non-markovian repairable fault trees

arXiv

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arXiv 2019年

作者： Budde, Carlos E. Biagi, Marco Monti, Raúl E. D'Argenio, Pedro R. Stoelinga, Mariëlle Formal Methods and Tools University of Twente Enschede Netherlands Department of Information Engineering University of Florence Florence Italy FAMAF Universidad Nacional de Córdoba Córdoba Argentina CONICET Córdoba Argentina Department of Computer Science Saarland University Saarbrücken Germany Department of Software Science Radboud University Nijmegen Netherlands

Dynamic fault trees (dft) are widely adopted in industry to assess the dependability of safety-critical equipment. Since many systems are too large to be studied numerically, dfts dependability is often analysed using Monte Carlo simulation. A bottleneck here is that many simulation samples are required in the case of rare events, e.g. in highly reliable systems where components fail seldomly. Rare event simulation (res) provides techniques to reduce the number of samples in the case of rare events. We present a res technique based on importance splitting, to study failures in highly reliable dfts. Whereas res usually requires meta-information from an expert, our method is fully automatic: By cleverly exploiting the fault tree structure we extract the so-called importance function. We handle dfts with Markovian and non-Markovian failure and repair distributions-for which no numerical methods exist-and show the efficiency of our approach on several case studies. Copyright © 2019, The Authors. All rights reserved.

关键词： Numerical methods

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Practitioner’s guide to social network analysis: Examining physics anxiety in an active-learning setting

引用

Physical Review Physics Education Research 2019年第2期15卷 020105-020105页

作者： Remy Dou Justyna P. Zwolak Department of Teaching and Learning Florida International University Miami Florida 33199 USA STEM Transformation Institute Florida International University Miami Florida 33199 USA Joint Center for Quantum Information and Computer Science University of Maryland College Park Maryland 20742 USA

[This paper is part of the Focused Collection on Quantitative methods in PER: A Critical Examination.] The application of social network analysis (SNA) has recently grown prevalent in science, technology, engineering, and mathematics education research. Research on classroom networks has led to greater understandings of student persistence in physics majors, changes in their career-related beliefs (e.g., physics interest), and their academic success. In this paper, we aim to provide a practitioner’s guide to carrying out research using SNA, including how to develop data collection instruments, setup protocols for gathering data, as well as identify network methodologies relevant to a wide range of research questions beyond what one might find in a typical primer. We illustrate these techniques using student anxiety data from active-learning physics classrooms. We explore the relationship between students’ physics anxiety and the social networks they participate in throughout the course of a semester. We find that students’ with greater numbers of outgoing interactions are more likely to experience decrease in anxiety even while we control for pre-anxiety, gender, and final course grade. We also explore the evolution of student networks and find that the second half of the semester is a critical period for participating in interactions associated with decreased physics anxiety. Our study further supports the benefits of dynamic group formation strategies that give students an opportunity to interact with as many peers as possible throughout a semester. To complement our guide to SNA in education research, we also provide a set of tools for other researchers to use this approach in their work—the SNA toolbox—that can be accessed on GitHub.

关键词： Instructional strategies Learning environment Research methodology

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Privacy-Preserving Task Assignment in Spatial Crowdsourcing

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Journal of computer science & Technology 2017年第5期32卷 905-918页

作者： An Liu Zhi-Xu Li Guan-Feng Liu Kai Zheng Min Zhang Qing Li Xiangliang Zhang School of Computer Science and Technology Soochow University Suzhou 215006 China School of Computer Science and Technology Soochow University Suzhou 215006 China Beijing Key Laboratory of Big Data Management and Analysis Methods Beijing 100872 China Department of Computer Science City University of Hong Kong Hong Kong China King Abdullah University of Science and Technology Thuwal 23955 Saudi Arabia

With the progress of mobile devices and wireless networks, spatial crowdsourcing （SC） is emerging as a promising approach for problem solving. In SC, spatial tasks are assigned to and performed by a set of human workers. To enable effective task assignment, however, both workers and task requesters are required to disclose their locations to untrusted SC systems. In this paper, we study the problem of assigning workers to tasks in a way that location privacy for both workers and task requesters is preserved. We first combine the Paillier cryptosystem with Yao＆#39;s garbled circuits to construct a secure protocol that assigns the nearest worker to a task. Considering that this protocol cannot scale to a large number of workers, we then make use of Geohash, a hierarchical spatial index to design a more efficient protocol that can securely find approximate nearest workers. We theoretically show that these two protocols are secure against semi-honest adversaries. Through extensive experiments on two real-world datasets, we demonstrate the efficiency and effectiveness of our protocols.

关键词： spatial crowdsourcing spatial task assignment location privacy mutual privacy protection

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Hackers vs. Security: Attack-Defence Trees as Asynchronous Multi-Agent Systems

arXiv

引用

arXiv 2019年

作者： Arias, Jaime Budde, Carlos E. Penczek, Wojciech Petrucci, Laure Stoelinga, Marielle LIPN CNRS UMR 7030 Universite Paris 13 Sorbonne Paris Cite Villetaneuse France Institute of Computer Science PAS Warsaw Poland University of Natural Sciences and Humanities II Siedlce Poland Formal Methods and Tools University of Twente Enschede Netherlands Department of Software Science Radboud University Nijmegen Netherlands

Attack-Defence Trees (ADTs) are well-suited to assess possible attacks to systems and the efficiency of counter-measures. In this paper, we first enrich the available constructs with reactive patterns that cover further security scenarios, and equip all constructs with attributes such as time and cost to allow quantitative analyses. Then, ADTs are modelled as (an extension of) Asynchronous Multi-Agents Systems- EAMAS. The ADT-EAMAS transformation is performed in a systematic manner that ensures correctness. The transformation allows us to quantify the impact of different agents configurations on metrics such as attack time. Using EAMAS also permits parametric verification: we derive constraints for property satisfaction. Our approach is exercised on several case studies using the Uppaal and IMITATOR tools. Copyright © 2019, The Authors. All rights reserved.

关键词： Multi agent systems

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The overlapping burden of the three leading causes of disability and death in sub-Saharan African children

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Nature Communications 2022年第1期13卷 1-14页

作者： Reiner, Robert C. Welgan, Catherine A. Troeger, Christopher E. Baumann, Mathew M. Weiss, Daniel J. Deshpande, Aniruddha Blacker, Brigette F. Miller-Petrie, Molly K. Earl, Lucas Bhatt, Samir Abolhassani, Hassan Abosetugn, Akine Eshete Abu-Gharbieh, Eman Adekanmbi, Victor Adetokunboh, Olatunji O. Aghaali, Mohammad Aji, Budi Alahdab, Fares Al-Aly, Ziyad Alhassan, Robert Kaba Ali, Saqib Alizade, Hesam Aljunid, Syed Mohamed Almasi-Hashiani, Amir Al-Mekhlafi, Hesham M. Altirkawi, Khalid A. Alvis-Guzman, Nelson Amare, Azmeraw T. Amini, Saeed Amugsi, Dickson A. Ancuceanu, Robert Andrei, Catalina Liliana Ansari, Fereshteh Anvari, Davood Appiah, Seth Christopher Yaw Arabloo, Jalal Aremu, Olatunde Atout, Maha Moh’d Wahbi Ausloos, Marcel Ausloos, Floriane Ayanore, Martin Amogre Aynalem, Yared Asmare Azene, Zelalem Nigussie Badawi, Alaa Baig, Atif Amin Banach, Maciej Bedi, Neeraj Bhagavathula, Akshaya Srikanth Bhandari, Dinesh Bhardwaj, Nikha Bhardwaj, Pankaj Bhattacharyya, Krittika Bhutta, Zulfiqar A. Bijani, Ali Birhanu, Tesega Tesega Mengistu Bitew, Zebenay Workneh Boloor, Archith Brady, Oliver J. Butt, Zahid A. Car, Josip Carvalho, Felix Casey, Daniel C. Chattu, Vijay Kumar Chowdhury, Mohiuddin Ahsanul Kabir Chu, Dinh-Toi Coelho, Camila H. Cook, Aubrey J. Damiani, Giovanni Daoud, Farah Gela, Jiregna Darega Darwish, Amira Hamed Daryani, Ahmad Das, Jai K. Davis Weaver, Nicole Deribe, Kebede Desalew, Assefa Dharmaratne, Samath Dhamminda Dianatinasab, Mostafa Diaz, Daniel Djalalinia, Shirin Dorostkar, Fariba Dubljanin, Eleonora Duko, Bereket Dwyer-Lindgren, Laura Effiong, Andem El Sayed Zaki, Maysaa El Tantawi, Maha Enany, Shymaa Fattahi, Nazir Feigin, Valery L. Fernandes, Eduarda Ferrara, Pietro Fischer, Florian Foigt, Nataliya A. Folayan, Morenike Oluwatoyin Foroutan, Masoud Frostad, Joseph Jon Fukumoto, Takeshi Gaidhane, Abhay Motiramji Gebrekrstos, Hailemikael Gebrekidan G. K. Gebremeskel, Leake Gebreslassie, Assefa Ayalew Gething, Peter W. Gezae, Kebede Embaye Ghadiri, Keyghobad Ghashghaee, Ahmad Golechha, Mahaveer Gubar Institute for Health Metrics and Evaluation University of Washington Seattle WA United States Department of Health Metrics Sciences School of Medicine University of Washington Seattle WA United States Malaria Atlas Project University of Oxford Oxford United Kingdom Imperial College London London United Kingdom Department of Laboratory Medicine Karolinska University Hospital Huddinge Sweden Research Center for Immunodeficiencies Tehran University of Medical Sciences Tehran Iran Department of Public Health Debre Berhan University Debre Berhan Ethiopia Department of Clinical Sciences University of Sharjah Sharjah United Arab Emirates Population Health Sciences King’s College London London United Kingdom Centre of Excellence for Epidemiological Modelling and Analysis Stellenbosch University Stellenbosch South Africa Department of Global Health Stellenbosch University Cape Town South Africa Department of Epidemiology and Biostatistics Qom University of Medical Sciences Qom Iran Faculty of Medicine and Public Health Jenderal Soedirman University Purwokerto Indonesia Mayo Evidence-based Practice Center Mayo Clinic Foundation for Medical Education and Research Rochester MN United States John T. Milliken Department of Internal Medicine Washington University in St. Louis St. Louis MO United States Clinical Epidemiology Center Department of Veterans Affairs St Louis MO United States Institute of Health Research University of Health and Allied Sciences Ho Ghana Department of Information Systems College of Economics and Political Science Sultan Qaboos University Muscat Oman Infectious and Tropical Disease Research Center Hormozgan University of Medical Sciences Bandar Abbas Iran Department of Health Policy and Management Kuwait University Safat Kuwait International Centre for Casemix and Clinical Coding National University of Malaysia Bandar Tun Razak Malaysia Department of Epidemiology Arak University of Medical Sciences Arak Iran Medical Research Center

Despite substantial declines since 2000, lower respiratory infections (LRIs), diarrhoeal diseases, and malaria remain among the leading causes of nonfatal and fatal disease burden for children under 5 years of age (under 5), primarily in sub-Saharan Africa (SSA). The spatial burden of each of these diseases has been estimated subnationally across SSA, yet no prior analyses have examined the pattern of their combined burden. Here we synthesise subnational estimates of the burden of LRIs, diarrhoea, and malaria in children under-5 from 2000 to 2017 for 43 sub-Saharan countries. Some units faced a relatively equal burden from each of the three diseases, while others had one or two dominant sources of unit-level burden, with no consistent pattern geographically across the entire subcontinent. Using a subnational counterfactual analysis, we show that nearly 300 million DALYs could have been averted since 2000 by raising all units to their national average. Our findings are directly relevant for decision-makers in determining which and targeting where the most appropriate interventions are for increasing child survival. © 2022, The Author(s).

关键词： Biogeography Epidemiology Infectious diseases Malaria

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Simulation studies of annihilation-photon’s polarisation via Compton scattering with the J-PET tomograph

引用

Hyperfine Interactions 2019年第1期240卷 1-5页

作者： Krawczyk, N. Hiesmayr, B.C. Chhokar, J. Curceanu, C. Czerwiński, E. Dulski, K. Gajos, A. Gorgol, M. Gupta-Sharma, N. Jasińska, B. Kisielewska, D. Korcyl, G. Kowalski, P. Krzemień, W. Kozik, T. Kubicz, E. Mohammed, M. Niedźwiecki, Sz. Palka, M. Pawlik-Niedźwiecka, M. Raczyński, L. Raj, J. Rakoczy, K. Rudy, Z. Sharma, S. Shivani Shopa, R.Y. Silarski, M. Skurzok, M. Wiślicki, W. Zgardzińska, B. Zieliński, M. Moskal, P. Faculty of Physics Astronomy and Applied Computer Science Jagiellonian University S. Lojasiewicza 11 Kraków30-348 Poland Faculty of Physics University of Vienna Boltzmanngasse 5 Vienna1090 Austria INFN Laboratori Nazionali di Frascati CP 13 Via E. Fermi 40 Frascati00044 Italy Department of Nuclear Methods Institute of Physics Maria Curie-Sklodowska University Pl. M. Curie-Sklodowskiej 1 Lublin20-031 Poland Department of Complex Systems National Centre for Nuclear Research Otwock-Świerk05-400 Poland High Energy Department National Centre for Nuclear Research Otwock-Świerk05-400 Poland

J-PET is the first positron-emission tomograph (PET) constructed from plastic scintillators. It was optimized for the detection of photons from electron-positron annihilation. Such photons, having an energy of 511 keV, interact with electrons in plastic scintillators predominantly via the Compton effect. Compton scattering is at most probable at an angle orthogonal to the electric field vector of the interacting photon. Thus registration of multiple photon scatterings with J-PET enables to determine the polarization of the annihilation photons. In this contribution we present estimates on the physical limitation in the accuracy of the polarization determination of 511 keV photons with the J-PET detector. © 2019, The Author(s).

关键词： Polarization

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Correction to: Global surface features contribute to human haptic roughness estimations

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Experimental brain research 2022年第4期240卷 1293页

作者： Huazhi Li Jiajia Yang Yinghua Yu Wu Wang Yulong Liu Mengni Zhou Qingqing Li Jingjing Yang Shiping Shao Satoshi Takahashi Yoshimichi Ejima Jinglong Wu Graduate School of Interdisciplinary Science and Engineering in Health Systems Okayama University 3-1-1 Tsushima-Naka Kita-ku Okayama 700-8530 Japan. Graduate School of Interdisciplinary Science and Engineering in Health Systems Okayama University 3-1-1 Tsushima-Naka Kita-ku Okayama 700-8530 Japan. yang@okayama-u.ac.jp. Section On Functional Imaging Methods National Institute of Mental Health Bethesda MD USA. yang@okayama-u.ac.jp. Section On Functional Imaging Methods National Institute of Mental Health Bethesda MD USA. School of Psychological and Cognitive Sciences Peking University Beijing China. Department of Teacher Education Wenzhou University Wenzhou China. School of Computer Science and Technology Changchun University of Science and Technology Changchun China. School of Social Welfare Yonsei University Seoul Korea. School of Mechatronical Engineering Beijing Institute of Technology Beijing China.

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