Physical Sciences and Mathematics Commons^™

Urban Scale Trade Area Characterization For Commercial Districts With Cellular Footprints, Yi Zhao, Zimu Zhou, Xu Wang, Tongtong Liu, Zheng Yang

Research Collection School Of Computing and Information Systems

Understanding customer mobility patterns to commercial districts is crucial for urban planning, facility management, and business strategies. Trade areas are a widely applied measure to quantify where the visitors are from. Traditional trade area analysis is limited to small-scale or store-level studies, because information such as visits to competitor commercial entities and place of residence is collected by labour-intensive questionnaires or heavily biased location-based social media data. In this article, we propose CellTradeMap, a novel district-level trade area analysis framework using mobile flow records (MFRs), a type of fine-grained cellular network data. We show that compared to traditional cellular data …

Attribute-Based Encryption For Cloud Computing Access Control: A Survey, Yinghui Zhang, Robert H. Deng, Shengmin Xu, Jianfei Sun, Qi Li, Dong Zheng

Research Collection School Of Computing and Information Systems

Attribute-based encryption (ABE) for cloud computing access control is reviewed in this article. A taxonomy and comprehensive assessment criteria of ABE are first proposed. In the taxonomy, ABE schemes are assorted into key-policy ABE (KP-ABE) schemes, ciphertext-policy ABE (CP-ABE) schemes, anti-quantum ABE schemes, and generic constructions. In accordance with cryptographically functional features, CP-ABE is further divided into nine subcategories with regard to basic functionality, revocation, accountability, policy hiding, policy updating, multi-authority, hierarchy, offline computation, and outsourced computation. In addition, a systematical methodology for discussing and comparing existing ABE schemes is proposed. For KP-ABE and each type of CP-ABE, the corresponding …

Smart Contract Repair, Xiao Liang Yu, Omar Al-Bataineh, David Lo, Abhik Roychoudhury

Research Collection School Of Computing and Information Systems

Smart contracts are automated or self-enforcing contracts that can be used to exchange assets without having to place trust in third parties. Many commercial transactions use smart contracts due to their potential benefits in terms of secure peer-to-peer transactions independent of external parties. Experience shows that many commonly used smart contracts are vulnerable to serious malicious attacks, which may enable attackers to steal valuable assets of involving parties. There is, therefore, a need to apply analysis and automated repair techniques to detect and repair bugs in smart contracts before being deployed. In this work, we present the first general-purpose automated …

How (Not) To Find Bugs: The Interplay Between Merge Conflicts, Co-Changes, And Bugs, Luis Amaral, Marcos C. Oliveira, Welder Luz, José Fortes, Rodrigo Bonifacio, Daniel Alencar, Eduardo Monteiro, Gustavo Pinto, David Lo

Research Collection School Of Computing and Information Systems

Context: In a seminal work, Ball et al. [1] investigate if the information available in version control systems could be used to predict defect density, arguing that practitioners and researchers could better understand errors "if [our] version control system could talk". In the meanwhile, several research works have reported that conflict merge resolution is a time consuming and error-prone task, while other contributions diverge about the correlation between co-change dependencies and defect density. Problem: The correlation between conflicting merge scenarios and bugs has not been addressed before, whilst the correlation between co-change dependencies and bug density has been only investigated …

The Impact Of Automated Feature Selection Techniques On The Interpretation Of Defect Models, Jirayus Jiarpakdee, Chakkrit Tantithamthavorn, Christoph Treude

Research Collection School Of Computing and Information Systems

The interpretation of defect models heavily relies on software metrics that are used to construct them. Prior work often uses feature selection techniques to remove metrics that are correlated and irrelevant in order to improve model performance. Yet, conclusions that are derived from defect models may be inconsistent if the selected metrics are inconsistent and correlated. In this paper, we systematically investigate 12 automated feature selection techniques with respect to the consistency, correlation, performance, computational cost, and the impact on the interpretation dimensions. Through an empirical investigation of 14 publicly-available defect datasets, we find that (1) 94–100% of the selected …

Wait For It: Identifying 'On-Hold' Self-Admitted Technical Debt, Rungroj Maipradit, Christoph Treude, Hideaki Hata, Kenichi Matsumoto

Research Collection School Of Computing and Information Systems

Self-admitted technical debt refers to situations where a software developer knows that their current implementation is not optimal and indicates this using a source code comment. In this work, we hypothesize that it is possible to develop automated techniques to understand a subset of these comments in more detail, and to propose tool support that can help developers manage self-admitted technical debt more effectively. Based on a qualitative study of 333 comments indicating self-admitted technical debt, we first identify one particular class of debt amenable to automated management: on-hold self-admitted technical debt (on-hold SATD), i.e., debt which contains a condition …

Human-Like Summaries From Heterogeneous And Time-Windowed Software Development Artefacts, Mahfouth Alghamdi, Christoph Treude, Markus Wagner

Research Collection School Of Computing and Information Systems

Automatic text summarisation has drawn considerable interest in the area of software engineering. It is challenging to summarise the activities related to a software project, (1) because of the volume and heterogeneity of involved software artefacts, and (2) because it is unclear what information a developer seeks in such a multi-document summary. We present the first framework for summarising multi-document software artefacts containing heterogeneous data within a given time frame. To produce human-like summaries, we employ a range of iterative heuristics to minimise the cosine-similarity between texts and high-dimensional feature vectors. A first study shows that users find the automatically …

A Methodology To Identify Alternative Suitable Nosql Data Models Via Observation Of Relational Database Interactions, Paul M. Beach

Theses and Dissertations

The effectiveness and performance of data-intensive applications are influenced by the suitability of the data models upon which they are built. The relational data model has been the de facto data model underlying most database systems since the 1970’s. However, the recent emergence of NoSQL data models have provided users with alternative ways of storing and manipulating data. Previous research has demonstrated the potential value in applying NoSQL data models in non-distributed environments. However, knowing when to apply these data models has generally required inputs from system subject matter experts to make this determination. This research, sponsored by the Air …

Chronos Spacecraft With Chiron Probe: Exploration Of The Hydrosphere, Principle Satellites, Atmosphere, And Rings Of Uranus, Payton E. Pearson

Theses and Dissertations

A design reference mission using more modern technological innovations has been developed for exploration of the outer reaches of our Solar System, specifically Uranus and its system of satellites. This mission will utilize theoretical technologies mostly without regard to their current technological readiness level (TRL), though most systems have a TRL of at least 5. The primary innovations explored in this thesis are the new launch systems that provide far greater payload capacity potentially sent to anywhere in the Solar System, new Stirling-engine radioisotope thermoelectric generators (SRTGs), vastly improved data storage technologies, optimized satellite antenna relay of data using much …

Pressure Driven Desalination Utilizing Nanomaterials, Fangyou Xie

Master's Theses

Nanomaterials such as graphene oxide and carbon nanotubes, have demonstrated excellent properties for membrane desalination, including decrease of maintenance, increase of flux rate, simple solution casting, and impressive chemical inertness. Here, two projects are studied to investigate nanocarbon based membrane desalination. The first project is to prepare hybrid membranes with amyloid fibrils intercalated with graphene oxide sheets. The addition of protein amyloid fibrils expands the interlayer spacing between graphene oxide nanosheets and introduces additional functional groups in the diffusion pathways, resulting in increase of flux rate and rejection rate for the organic dyes. Amyloid fibrils also provide structural assistance to …

Mapping Geographical Inequalities In Access To Drinking Water And Sanitation Facilities In Low-Income And Middle-Income Countries, 2000–17, Aniruddha Deshpande, Robert C. Reiner Jr, Veincent Christian F. Pepito, Arianna Maever L. Amit, Local Burden Of Disease Wash Collaborators, 665 Co-Authors

Ateneo School of Medicine and Public Health Publications

Background

Universal access to safe drinking water and sanitation facilities is an essential human right, recognised in the Sustainable Development Goals as crucial for preventing disease and improving human wellbeing. Comprehensive, high-resolution estimates are important to inform progress towards achieving this goal. We aimed to produce high-resolution geospatial estimates of access to drinking water and sanitation facilities.

Methods

We used a Bayesian geostatistical model and data from 600 sources across more than 88 low-income and middle-income countries (LMICs) to estimate access to drinking water and sanitation facilities on continuous continent-wide surfaces from 2000 to 2017, and aggregated results to policy-relevant …

Observing And Measuring Water Quality Of Central California Estuaries For Steelhead Trout (Onchorynchus Mykiss), Charles Alexander Taylor

Master of Science in Environmental Sciences and Management Projects

Estuaries support abundant biodiversity but are threatened by anthropogenic influences making it a priority to effectively monitor water quality to identify if and when it becomes detrimental to aquatic life. The purpose of the study was to analyze water quality in local San Luis Obispo estuaries to measure baseline conditions to inform future studies and management and to identify if key water quality parameters such as dissolved oxygen or temperature result in stressful or lethal conditions for steelhead trout (Onchorynchus mykiss). An EXO1 multiparameter snode (probe) was used to measure dissolved oxygen (mg/l), temperature (in Celsius), conductivity (Us/cm), salinity (parts …

Simulation Of Physical Field Of 300ka Prebaked Aluminum Reduction Cell, Shuiping Zeng, Shasha Wang, Rongjuan Wang

Journal of System Simulation

Abstract: The SY300 Prebake cell of some factory as a basic simplified model, the solidworks software was used to build a three-dimensional physical model of aluminum reduction cell. In the use of some assumptions, reasonable ideal field segmentation and under the premise of sharing model information and results, the physical model of electric field, magnetic field, flow field and its calculation module of coupling field were established respectively by using the the finite element software Comsol and Matlab Multiphysics software. On Comsol platform, electric, magnetic field of aluminum electrolytic cell were solved when replacing the anode, and current density …

Traffic Simulation Of Elementary And Middle School's Gate Road During Student Departing School Based On Ca Model, Mingbao Pang, Chen Jing, Yang Min

Journal of System Simulation

Abstract: The simulation problem of student departing school to the traffic flow of elementary and middle school's gate road was studied by using a cellular automaton model. Based on STNS (symmetric two-lane Nagel-Schreckenberg) model, a cellular automaton model on the interference road section of elementary and middle school's gate during student departure school was established. The traffic flow characteristics of the road during student departure school time were discussed via the simulation experiment. The effects were analyzed how the proportion of students departing school by private cars, the proportion of students departing school by school buses, and the …

Energy Entropy And Particle Swarm Optimization Bp Neural Network Of Fault Diagnosis Techniques Of Coal Mine Cable, Zhiling Ren, Yuanyuan Zhang

Journal of System Simulation

Abstract: Aimed at solving the problem of the type of fault difficult to identification when power feeder of coal mine occurred single-phase ground fault, in order to ensure coal mines production safety, a method of fault diagnosis based on wavelet packet energy entropy (WP-EE) and combined with particle swarm optimization neural network was proposed. The type of cable fault was simulated by Matlab, the acquired post-fault voltage signal was performed the three layers wavelet Packet decomposition, the fault characteristic signals was divided into eight segments by frequency, characteristics calculated the entropy energy spectrum according to the information entropy theory, …

Fault Diagnosis Of Reverse Osmosis Water Desalination Based On Optimized Support Vector Machine, Zhang Biao, Jianfeng Xing, Zhicheng Ji

Journal of System Simulation

Abstract: According to the reverse osmosis membrane fault problems in reverse osmosis water desalination system, a fault diagnosis method based on support vector machine (SVM) was introduced for fault diagnoses. To solve the problem of parameter optimization in SVM, an improved chaos particle swarm algorithm was proposed. The introduction of Chaos theory to particle swarm optimization algorithm may not only enhance the diversity of the population and particle global search ability, but also improve the convergence speed and accuracy of the particle swarm algorithm. The optimized SVM model was applied to the fault diagnosis of reverse osmosis water desalination system. …

Research On Parallel Simulation Of Hypersonic Vehicles, Xuegong Sun, Chunye Gong

Journal of System Simulation

Abstract: The system simulation of hypersonic vehicles was a multi-physics coupling process. It needed many iterations with large scale data to finish the simulation. To fix up the computational challenges, the distributed simulation was developed. But distributed simulation had no obvious effect on the computational efficiency. In order to enhance the computational efficiency, the grid parallel method and model parallel algorithm were studied based on the high performance cluster system. The parallel simulation method for fluid dynamics, data exchange method for partition boundary and load balance technology for parallel computing were developed and applied to the system simulation of hypersonic …

Hardware-In-The-Loop Test-Bed For Testing Of Lunar Rover Gnc Based On Vision-In-The-Loop, Zhiping Li, Zhang Zhi, Jianxin Chen, Wang Lei, Hehua Ju

Journal of System Simulation

Abstract: A hardware-in-the-loop and vision-in-the-loop test-bed for the testing of the lunar rover guide navigation control (GNC) subsystem was introduced. The composition of the test-bed and its dataflow were delicately designed. Then the vision-in-the-loop concept was designed. To overcome the problem of matching between the hazard-camera's focus and the images' distortion parameters, the distortion computation on the edge of the image pixels was ignored. Furthermore, to fulfill the closed-loop testing, the stereo vision function was accomplished by using multiple processes that made the images rapidly generated and the cameras' position and attitude parameters were supplied from rover's dynamics. Many …

Decision Strategy Models Of Merge Influence Area For Outside Vehicles Based On Vehicle-Vehicle Communication, Xiaofang Yang, Guo Qian, Fu Qiang

Journal of System Simulation

Abstract: In the on-ramp merging area, appropriate driving decisions should be made by observing the running environment and estimating the driving characteristics of the surrounding vehicles, which usually led to the inordinate traffic flow. To solve this problem, the decision strategy models were built for vehicles in the on-ramp merging area, and the operating rules for the new decision strategy were updated. Furthermore, the space-time trajectory, the lane changing in merging and upstream area and the average speed in the two different circumstances were analyzed by numerical experiments. The results show that in the condition of vehicle-vehicle communication environment, …

The Electronic Properties Of The Quasi-One-Dimensional Transition Metal Trichalcogenides: Tis3 And Zrs3, Simeon Gilbert

Department of Physics and Astronomy: Dissertations, Theses, and Student Research

The transition metal trichalcogenides are a class of materials formed by 1D chains of covalently bound MX₃ (M=Ti, Zr, Hf, Ta, Nb; X=S, Se, Te) trigonal prisms which are held together by weak van der Waals forces to form 2D sheets. Because of their superior edge termination, these materials suppress edge scattering effects that plague other two-dimensional materials thus enabling devices scaling to widths below 10 nm. Furthermore, this quasi-one-dimensional structure results in highly anisotropic electronic and optical properties which were examined through angle resolved photoemission spectroscopy and scanning photocurrent microscopy. These measurements show that the hole carrier masses …

Variability Of Active Galactic Nuclei From Differential Photometry, Nicholas Steven Yee

Physics

The Seoul AGN Monitoring Project, or SAMP for short, is an international project (PI Jonghak Woo from Korea) with the goal of measuring the masses of black holes residing in the center of massive active galactic nuclei (AGNs). AGNs are some of the brightest objects in the universe. Their light is attributed to the accretion of material onto the black hole. However, these objects are too distant to spatially resolve the gravitational sphere of influence of the black hole directly. Instead, we use a technique called reverberation mapping which observes the variability of the AGN power-law continuum emission and the …

Examining The Statistical Relationships Between Volcanic Seismic, Infrasound, And Electrical Signals: A Case Study Of Sakurajima Volcano, 2015, Cassandra M. Smith, Glenn Thompson, Steven Reader, Sonja A. Behnke, Stephen R. Mcnutt, Ron Thomas, Harald Edens

School of Geosciences Faculty and Staff Publications

Sakurajima volcano in Japan is known for frequent eruptions containing prolific volcanic lightning. Previous studies from eruptions at Redoubt have shown preliminary correlations between seismic, infrasound, and radio frequency signals. This study uses field data collected at Sakurajima from 28 May–7 June 2015 and multivariable statistical modeling to quantify these relationships. We build regression equations to examine each of the following parameters of electrical activity: (1) the presence of electrical activity, (2) the presence of the radio frequency signal called continual radio frequency impulses (CRF), (3) the presence of lightning, (4) the overall duration of electrical activity, and (5) the …

Linear And Non-Linear Elastic Constants Of Crystalline Materials From First-Principles Calculations, David Cuffari

Dissertations, Theses, and Capstone Projects

Novel methods based on the use of density functional theory (DFT) calculations are developed and applied to calculate linear and non-linear elastic constants of materials at zero and finite temperature. These methods rely on finite difference techniques and are designed to be general, numerically accurate, and suitable to investigate the thermoelastic properties of anharmonic materials. A first method was developed to compute the third-order elastic constants of crystalline materials at zero temperature, a task that is numerically challenging and is currently undertaken by using approaches typically applicable to cubic and hexagonal crystalline systems. This method relies on numerical differentiation of …

Peo-Ppo-Peo Surfactant Mixtures As Templates For Silicas With Very Large Cylindrical Mesopores At Ambient Temperature And With Helical Mesopores At Sub-Ambient Temperature, Laurance Beaton

Dissertations, Theses, and Capstone Projects

The original research described herein concerns the synthesis of mesoporous silicas through a surfactant-templating method. The approach taken involved the use of a mixed surfactant system of two poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) surfactants, with one of the copolymers containing a much larger percentage of hydrophobic (PPO) blocks than the employed co-surfactant. Systematic adjustments of experimental parameters initially enabled the preparation of 2-D hexagonally ordered mesoporous silicas (SBA-15) of uncommonly large pore diameter at ambient temperature. Comparable silica was synthesized with and without temperature control. Additional adjustments to experimental parameters, including reduction of the relative amount of framework precursor used in …

Tile Based Self-Assembly Of The Rook's Graph, Ernesto Gonzalez

Electronic Theses, Projects, and Dissertations

The properties of DNA make it a useful tool for designing self-assembling nanostructures. Branched junction molecules provide the molecular building blocks for creating target complexes. We model the underlying structure of a DNA complex with a graph and we use tools from linear algebra to optimize the self-assembling process. Some standard classes of graphs have been studied in the context of DNA self-assembly, but there are many open questions about other families of graphs. In this work, we study the rook's graph and its related design strategies.

Global Patterns Of Recent Mass Movement On Asteroid (101955) Bennu, E. R. Jawin, K. J. Walsh, O. S. Barnouin, T. J. Mccoy, R.-L. Ballouz, D. N. Dellagiustina, Harold Connolly Jr.

School of Earth & Environment Departmental Research

The exploration of near‐Earth asteroids has revealed dynamic surfaces characterized by mobile, unconsolidated material that responds to local geophysical gradients, resulting in distinct morphologies and boulder distributions. The OSIRIS‐REx (Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer) mission confirmed that asteroid (101955) Bennu is a rubble pile with an unconsolidated surface dominated by boulders. In this work, we documented morphologies indicative of mass movement on Bennu and assessed the relationship to slope and other geologic features on the surface. We found globally distributed morphologic evidence of mass movement on Bennu up to ~70° latitude and on spatial scales ranging from …

Topography Of The 410 And 660 Km Discontinuities Beneath The Cenozoic Okavango Rift Zone And Adjacent Precambrian Provinces, Youqiang Yu, Stephen S. Gao, Kelly H. Liu

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

By taking advantage of the recent availability of a broadband seismic data set from Networks NR and BX covering the entire country of Botswana, we conduct a systematic receiver function investigation of the topography of the 410 and 660 km discontinuities beneath the incipient Okavango rift zone (ORZ) in northern Botswana and its adjacent Archean-Proterozoic tectonic provinces in southern Africa. Similar to a previous mantle transition zone (MTZ) discontinuity study using data from a 1-D profile traversing the ORZ, a normal MTZ thickness is observed in most parts of the study area. This is inconsistent with the existence of widespread …

Student Preclass Preparation By Both Reading The Textbook And Watching Videos Online Improves Exam Performance In A Partially Flipped Course, Kaleb Bassett, Gayla R. Olbricht, Katie Shannon

Mathematics and Statistics Faculty Research & Creative Works

The flipped classroom has the potential to improve student performance. Because flipping involves both preclass preparation and problem solving in the classroom, the means by which increased learning occurs and whether the method of delivering content matters is of interest. In a partially flipped cell biology course, students were assigned online videos before the flipped class and textbook reading before lectures. Low-stakes assessments were used to incentivize both types of preclass preparation. We hypothesized that more students would watch the videos than read the textbook and that both types of preparation would positively affect exam performance. A multiple linear regression …

Yellowstone National Park - Pems Snowcoach Measurements, University Of Denver

Non-Road Vehicle Data

Relevant Publications

Environmental Science & Technology Publication (2006)

Air & Waste Management Publication (2009)

Environmental Science & Technology Publication (2014)

2005 Final Report

2006 Final Report

2012 Final Report

Plithogenic Cubic Sets, Florentin Smarandache, S.P. Priyadharshini, F. Nirmala Irudayam

Branch Mathematics and Statistics Faculty and Staff Publications

In this article, using the concepts of cubic set and plithogenic set, the ideas of plithogenic fuzzy cubic set, plithogenic intuitionistic fuzzy cubic set, plithogenic neutrosophic cubic set are introduced and its corresponding internal and external cubic sets are discussed with examples.