Algorithms, applications and systems towards interpretable pattern mining from multi-aspect data

How do humans move around in the urban space and how do they differ when the city undergoes terrorist attacks? How do users behave in Massive Open Online courses~(MOOCs) and how do they differ if some of them achieve certificates while some of them not? What areas in the court elite players, such as Stephen Curry, LeBron James, like to make their shots in the course of the game? How can we uncover the hidden habits that govern our online purchases? Are there unspoken agendas in how different states pass legislation of certain kinds? At the heart of these seemingly unconnected puzzles is this same mystery of multi-aspect mining, i.g., how can we mine and interpret the hidden pattern from a dataset that simultaneously reveals the associations, or changes of the associations, among various aspects of the data (e.g., a shot could be described with three aspects, player, time of the game, and area in the court)? Solving this problem could open gates to a deep understanding of underlying mechanisms for many real-world phenomena. While much of the research in multi-aspect mining contribute broad scope of innovations in the mining part, interpretation of patterns from the perspective of users (or domain experts) is often overlooked. Questions like what do they require for patterns, how good are the patterns, or how to read them, have barely been addressed. Without efficient and effective ways of involving users in the process of multi-aspect mining, the results are likely to lead to something difficult for them to comprehend. This dissertation proposes the M^3 framework, which consists of multiplex pattern discovery, multifaceted pattern evaluation, and multipurpose pattern presentation, to tackle the challenges of multi-aspect pattern discovery. Based on this framework, we develop algorithms, applications, and analytic systems to enable interpretable pattern discovery from multi-aspect data. Following the concept of meaningful multiplex pattern discovery, we propose PairFac to close the gap between human information needs and naive mining optimization. We demonstrate its effectiveness in the context of impact discovery in the aftermath of urban disasters. We develop iDisc to target the crossing of multiplex pattern discovery with multifaceted pattern evaluation. iDisc meets the specific information need in understanding multi-level, contrastive behavior patterns. As an example, we use iDisc to predict student performance outcomes in Massive Open Online Courses given users' latent behaviors. FacIt is an interactive visual analytic system that sits at the intersection of all three components and enables for interpretable, fine-tunable, and scrutinizable pattern discovery from multi-aspect data. We demonstrate each work's significance and implications in its respective problem context. As a whole, this series of studies is an effort to instantiate the M^3 framework and push the field of multi-aspect mining towards a more human-centric process in real-world applications

Essays on physical and financial well-being in low- and middle-income countries

Many socio-economic factors are threatening the physical, mental, and financial well-being among the population residing in low- and middle-income countries, including financial stress, discrimination, violence, health issues, and inequalities. In the five chapters of my dissertation, I exploit experimental or quasi-experimental natures of socio-economic shocks in China, Peru and Uganda, to measure their impacts on the physical and financial well-being on individuals. The first chapter of this dissertation provides information on the study background, the data and presents an overview of each chapter. The remainder of the dissertation consists of five essays stretching out over the next chapters. China is well-known for its skewed sex ratios and huge demographic imbalance. In the first chapter, I exploit a cross-cohort spatial comparison to analyze the impact of demographic imbalance on the payment of brideprices and dowries in China. This chapter exploits the variation of sex ratios exposed to children born in the same natal family but born in different years. I use a difference-in-difference estimation and provide the very first empirical evidence that an increase in male surplus leads to higher incidence and value of brideprices, but it has no effect on dowries. Subsequent investigations reveal that brideprices and dowries carry different significance in the Chinese society, which explains the co-existence and co-development of both payments in the 21st century. Chapter 3 analyzes the negative health impact of rising housing prices in China. There is massive housing price appreciation since the early 2000s, which caused huge financial stress to households because of the strong social norm of owning rather than renting a house or apartment. We highlight that the high competition among males in the marriage market due to the “missing women” phenomenon is an important factor that contributes to such a negative health effect. Chapter 4 shows that natural disasters would elevate the incidence of intimate partner violence through higher alcohol use by the male partner, higher likelihood of co-residing with the male partner, and an increase in male intra-household economic power. Moreover, we highlight that the access to protective institutions, such as the “women justice centers”, are of vital importance to women’s vulnerability of intra-household violence. This paper points out one important but often neglected socio-economic consequence of natural disasters, and provides a strong policy implication for the post-disaster relief and reconstruction. The last two chapters are based on data collected in Uganda. The fourth chapter evaluates the impact of a financial education program on the use of digital finance (mobile money) as well as the business performance and household finance among microentrepreneurs in rural Uganda. We design a randomized saturation experiment, and find a positive impact of financial education on the use of mobile money, saving promotion, and business investments on targeted entrepreneurs. At the same time, we do not find evidence of positive spillover effects on the untreated ones in treated clusters. Instead, the estimated spillover coefficients often show negative (albeit insignificant) signs. In the last chapter, we document that the COVID-19 lockdown increases the financial stress of the micro-entrepreneurs in rural Uganda in the long term

Structured representation learning from complex data

This thesis advances several theoretical and practical aspects of the recently introduced restricted Boltzmann machine - a powerful probabilistic and generative framework for modelling data and learning representations. The contributions of this study represent a systematic and common theme in learning structured representations from complex data

Improvement of acoustic emission technology for stress corrosion cracking

This thesis was submitted for the award of Doctor of Philosophy and was awarded by Brunel University LondonThis thesis investigates the advancement of Acoustic emission (AE) monitoring techniques and analysis methods that could be applied in the field of Structural Health Monitoring (SHM), with an emphasis on the use of advanced AE techniques to detect and locate damage and their application on the monitoring of corrosion and Stress corrosion cracking (SCC) in complex metallic structures. The work was divided into three main areas of research, which are an investigation into using FE (Finite Element) generated delta-T mapping to locate experimental AE signals on complex structures, source location of AE signals generated by corrosion and an experimental investigation into SCC damage locations on a metallic specimen.Lloyd's Register Foundation, Brunel University London and the National Structural Integrity Research Centre (NSIRC

NASA Tech Briefs, December 1990

Topics: New Product Ideas; NASA TU Services; Electronic Components and Circuits; Electronic Systems; Physical Sciences; Materials; Computer Programs; Mechanics; Machinery; Fabrication Technology; Mathematics and Information Sciences; Life Sciences

Studies relating to ground anchorage systems

This thesis comprises 28 papers which illustrate the nature and direction of development work and associated research undertaken between 1965 and 1993 on soil and rock anchorage systems. The research was performed in order to obtain a basic understanding of the behaviour of newly developed anchorage systems in a variety of ground types and conditions, in order to improve anchorage designs, construction methods and testing procedures, and thereby encourage the safe and economic application of ground anchorages worldwide. Field development of anchorage construction methods in gravels, sand, clays, marls and chalk using cement grout injection techniques is described together with equations evolved to estimate the ultimate resistance to withdrawal for each ground type, based on systematic testing of full scale anchorages. A new design method for single and multi tied stiff retaining walls installed in any soil is detailed and validated by large scale tests and closely monitored case histories. The interactions between wall, anchorage and soil are illustrated, coupled with the refinement of overall stability analyses in cohesionless soils using wedge and log spiral based mechanisms of failure. For the rapid installation of anchorages in granular soils, vibratory driving is investigated in the laboratory and two distinct types of motion are found to exist. Theoretical equations of motion are developed to define the penetration processes and facilitate the design of vibrodrivers and vibrohammers. World practice in relation to the design, construction, testing and behaviour of rock anchorages is appraised, and field studies permit an improved understanding of uplift capacity by general shear failure, load transfer mechanisms, bond at rock/grout and grout/tendon interfaces, debonding, service performance and post-failure behaviour. Acceptance criteria related to service behaviour are created for load relaxation and creep displacement with time, which are independent of ground type and potentially of short duration. The extent and nature of steel tendon corrosion is described based on an international study of the corrosion performance of post-tensioned anchorages. Guidance is provided on class of protection, design principles and acceptable protective systems. For rock tunnelling by drill and blast methods of excavation, a fundamental understanding of rock bolt behaviour under static and dynamic loading is provided. Field, laboratory and finite element studies are combined to investigate the character of blast induced wave forms within a rock mass and the effect of these signatures on the rock bolt system. Attenuation relationships for peak particle velocity and peak dynamic bolt load are presented together with effect of bolt prestress, bolt length, and both single and two speed resin systems. Observations confirm that resin bonded rock bolts have a remarkable resilience to close proximity blasting, and the data provide a new understanding of stress transfer in tensioned bolts under static and dynamic conditions. A simple device to control rock bolt tensioning is developed and applied as a result of observed variations in prestress during production bolting. Ground anchorage technology is reviewed to highlight areas where further investigation and study would enhance understanding of anchorage behaviour and improve standards of practice.PUBLICATIONS INCLUDED IN THESIS: #2. HSU, T.C., LITTLEJOHN, G.S. & MARCHBANK, B.M. (1965) "Elongation in the Tension Test as a Measure of Ductility" Proc. Amer. Soc. Test. Mat., 65, 874-98. (Hsu wrote the paper and supervised the research of Littlejohn and Marchbank who provided the data.) #3. LITTLEJOHN, G.S. (1968) "Recent Developments in Ground Anchor Construction" Ground Engineering, 1(3), 32-36 & 46. #4. HANNA, T.H. & (1969) "Retaining Wall Tie-Backs" LITTLEJOHN, G.S. Consulting Engineer, May, 50-53, June, 49-52. (Hanna and Littlejohn contributed equally to this paper.) #6. LITTLEJOHN, G.S. #8. LITTLEJOHN, G.S., JACK, B.J. & SLIWINSKI, Z.J. (1971) "Anchored Diaphragm Walls - Some Design and Construction Considerations" Journal of the Institution of Highway Engineers, 18 (4), 15-29. (Littlejohn co-ordinated this paper and contributed half the data.) #13. LITTLEJOHN, G.S. & (1974) "A Case History Study of Multi-Tied Diaphragm MACFARLANE, I.M. Walls" Proc. Conf. on Diaphragm Walls and Anchorages, 113-121, Institution of Civil Engineers, London. (Littlejohn wrote the paper. Macfarlane provided technical data.) #14. LITTLEJOHN, G.S. & (1974) "Ground Anchors at Devonport Nuclear Complex" TRUMAN-DAVIES, C. Ground Engineering, 7 (6), 19-24. (Littlejohn wrote the paper. Truman-Davies supervised the field work.) #16. LITTLEJOHN, G.S. & (1975) "Rock Anchors - State-of-the-Art Part 1: Design" BRUCE, D.A. Ground Engineering, 8 (3), 25-32, 8 (4), 41-48. (Littlejohn wrote the paper and supervised Bruce's Ph.D. programme.) #18. LITTLEJOHN, G.S. & (1975) "Rock Anchors - State-of-the-Art Part 2; BRUCE, D.A. Construction" Ground Engineering, 8 (5), 34-45, 8 (6), 36-45. (Littlejohn wrote the paper and supervised Bruce's Ph.D. programme.) #19. LITTLEJOHN, G.S. & (1976) "Rock Anchors - State-of-the-Art Part 3: Stressing BRUCE, D.A. and Testing" Ground Engineering, 9 (2), 20-29, 9 (3), 55-60, 9 (4), 33-44. (Littlejohn wrote the paper and supervised Bruce's Ph.D. programme.) #20. LITTLEJOHN, G.S., (1977) "A Study of Rock Slope Reinforcement at Westfield NORTON, P.J. & Open Pit and the Effect of Blasting on Prestressed TURNER, M.J. Anchors" Proc. Conference on Rock Engineering, University of Newcastle-upon-Tyne, England. (Littlejohn wrote the paper. Norton and Turner provided technical data.) #22. LITTLEJOHN, G.S., (1977) "Anchor Field Tests in Carboniferous Strata" BRUCE, D.A. & Revue Francaise de Geotechnique No. 3, DEPPNER, W. January 1978, 82-86. (Littlejohn wrote the paper. Bruce and Deppner provided field data.) #28. LITTLEJOHN, G.S. & (1979) "Long Term Performance of High Capacity Rock BRUCE, D.A. Anchors at Devonport" Ground Engineering, 12 (7), 25-33. (Littlejohn and Bruce jointly wrote the paper. Bruce provided the field data under the supervision of Littlejohn.) #29. LITTLEJOHN, G.S. #30. LITTLEJOHN, G.S. #32. RODGER, A.A. & (1980) "A Study of Vibratory Driving in Granular Soils" LITTLEJOHN, G.S. Geotechnique, 30 (3), 269-93. (Rodger and Littlejohn jointly wrote the paper. Littlejohn supervised Rodger's Ph.D. programme) #34. LITTLEJOHN, G.S. (1981) "Acceptance Criteria for the Service Behaviour of Ground Anchorages" Ground Engineering, 14 (3), 26-29 & 36. #36. LITTLEJOHN, G.S. #50. LITTLEJOHN, G.S. (1987) "Ground Anchorages : Corrosion Performance" Proc. Instn. Civ. Engrs., Part 1, 82, 645-662. #51. LITTLEJOHN, G.S., (1987) "Monitoring the Influence of Blasting on the RODGER, A.A., Performance of Rock Bolts at Penmaenbach MOTHERSILLE, D.K.V. Tunnel" & HOLLAND, D.C. Proc. Int. Conf. on Foundations and Tunnels, University of London, 1,99-106. (Littlejohn and Rodger jointly wrote the paper and supervised Mothersille's and Holland's research work.) #52. LITTLEJOHN, G.S. (1988) "Sprayed Concrete for Underground Support" Proc. 3rd Int. Conf. on Underground Space and Earth Sheltered Buildings, Shanghai, China. #53. LITTLEJOHN, G.S. (1988) "Rock Anchorages for Underground Support" Proc. 3rd Int. Conf. on Underground Space and Earth Sheltered Buildings, Shanghai, China. "Thermal Behaviour of Grouted Supports for Pipelines" Department of Energy - Offshore Technology Report 'Grouts and Grouting for Construction and Repair of Offshore Structures', OTH 88289, 111-120. (Littlejohn and Hughes jointly wrote the paper. Hughes provided the laboratory data under Littlejohn's supervision.) #56. RODGER, A.A., (1989) "Instrumentation Used to Monitor the LITTLEJOHN, G.S., Influence of Blasting on the Performance of HOLLAND, D.C. & Rock Bolts at Penmaenbach Tunnel" MOTHERSILLE, D.K.V. Proc. Conf. on Instrumentation in Geotechnical Engineering, University of Nottingham, 267-279. (Rodger and Littlejohn jointly wrote the paper and supervised Mothersille's and Holland's research work.) #58. LITTLEJOHN, G.S., (1989) "Dynamic Response of Rock Bolt Systems" RODGER, A.A., Proc. Int. Conf. on Foundations and Tunnels, MOTHERSILLE, D.K.V. University of London (Sept.), 2, 57-64. & HOLLAND, D.C. (Littlejohn and Rodger wrote the paper and supervised Mothersille's and Holland's research work.) #61. LITTLEJOHN, G.S. #62. LITTLEJOHN, G.S. #64. LITTLEJOHN, G.S. #74. RODGER, A.A., (1993) "Dynamic Response of Rock Bolts at Pen y Clip LITTLEJOHN, G.S., Tunnel in North Wales" HOLLAND, D.C. & Proc. Int. Cong, on Options for Tunnelling, Int. XU, H. Tunnelling Assoc., Amsterdam. (Rodger and Littlejohn jointly wrote the paper and supervised Holland's and Xu's research.) #75. LITTLEJOHN, G.S. (1993) "A Simple Device to Control Rock Bolt Tensioning" & CONWAY, J. Tunnels & Tunnelling, (in press). (Littlejohn and Conway jointly wrote the paper. Littlejohn planned and supervised the experimental work.

Latent variable regression and applications to planetary seismic instrumentation

The work presented in this thesis is framed by the concept of latent variables, a modern data analytics approach. A latent variable represents an extracted component from a dataset which is not directly measured. The concept is first applied to combat the problem of ill-posed regression through the promising method of partial least squares (PLS). In this context the latent variables within a data matrix are extracted through an iterative algorithm based on cross-covariance as an optimisation criterion. This work first extends the PLS algorithm, using adaptive and recursive techniques, for online, non-stationary data applications. The standard PLS algorithm is further generalised for complex-, quaternion- and tensor-valued data. In doing so it is shown that the multidimensional algebras facilitate physically meaningful representations, demonstrated through smart-grid frequency estimation and image-classification tasks. The second part of the thesis uses this knowledge to inform a performance analysis of the MEMS microseismometer implemented for the InSight mission to Mars. This is given in terms of the sensor's intrinsic self-noise, the estimation of which is achieved from experimental data with a colocated instrument. The standard coherence and proposed delta noise estimators are analysed with respect to practical issues. The implementation of algorithms for the alignment, calibration and post-processing of the data then enabled a definitive self-noise estimate, validated from data acquired in ultra-quiet, deep-space environment. A method for the decorrelation of the microseismometer's output from its thermal response is proposed. To do so a novel sensor fusion approach based on the Kalman filter is developed for a full-band transfer-function correction, in contrast to the traditional ill-posed frequency division method. This algorithm was applied to experimental data which determined the thermal model coefficients while validating the sensor's performance at tidal frequencies 1E-5Hz and in extreme environments at -65C. This thesis, therefore, provides a definitive view of the latent variables perspective. This is achieved through the general algorithms developed for regression with multidimensional data and the bespoke application to seismic instrumentation.Open Acces

Remote Sensing

This dual conception of remote sensing brought us to the idea of preparing two different books; in addition to the first book which displays recent advances in remote sensing applications, this book is devoted to new techniques for data processing, sensors and platforms. We do not intend this book to cover all aspects of remote sensing techniques and platforms, since it would be an impossible task for a single volume. Instead, we have collected a number of high-quality, original and representative contributions in those areas