Cyber-Physical Systems: A Model-Based Approach

In this concise yet comprehensive Open Access textbook, future inventors are introduced to the key concepts of Cyber-Physical Systems (CPS). Using modeling as a way to develop deeper understanding of the computational and physical components of these systems, one can express new designs in a way that facilitates their simulation, visualization, and analysis. Concepts are introduced in a cross-disciplinary way. Leveraging hybrid (continuous/discrete) systems as a unifying framework and Acumen as a modeling environment, the book bridges the conceptual gap in modeling skills needed for physical systems on the one hand and computational systems on the other. In doing so, the book gives the reader the modeling and design skills they need to build smart, IT-enabled products. Starting with a look at various examples and characteristics of Cyber-Physical Systems, the book progresses to explain how the area brings together several previously distinct ones such as Embedded Systems, Control Theory, and Mechatronics. Featuring a simulation-based project that focuses on a robotics problem (how to design a robot that can play ping-pong) as a useful example of a CPS domain, Cyber-Physical Systems: A Model-Based Approach demonstrates the intimate coupling between cyber and physical components, and how designing robots reveals several non-trivial control problems, significant embedded and real-time computation requirements, and a need to consider issues of communication and preconceptions

Estimating fugitive bioaerosol releases from static compost windrows: feasibility of portable wind tunnel approach

An assessment of the fugitive release of bioaerosols from static compost piles was conducted at a green waste composting facility in South East England; this representing the initial stage of a programme of research into the influence of process parameters on bioaerosol emission flux. Wind tunnel experiments conducted on the surface of static windrows generated specific bioaerosol emission rates (SBER2s) at ground level of between 13 - 22 x10 3 cfu/m 2 /s for mesophilic actinomycetes and between 8 - 11 x10 3 cfu/m 2 /s for Aspergillus fumigatus. Air dispersion modelling of these emissions using the SCREEN3 air dispersion model in area source term mode was used to generate source depletion curves downwind of the facility for comparative purposes

A Data Warehouse Architecture Model for Al-Quds Open University

Data warehousing is important, not only in business enterprises, but in the university environment as well. The goal of a data warehouse is to integrate timely, accurate information and to make it available to an organization's employees and decision makers. The data warehouse is developing in response to increasing data and information requirements. The traditional notion of data warehouses is evolving into a federated warehouse augmented by a set of processes and services to support integrated and consistent access to heterogeneous, decentralized warehouse systems. This study will explore the design and implementation of a data warehouse architecture model for the Al-Quds Open University (QOU) in Palestine, within the Context of Relational Online Analytical Processing (OLAP). The model aims at integrating data from different sources in the QOU

Static and Seismic Performance of Geosynthetics-Strengthened Pile Foundations

Geosynthetic reinforcement in earth structures has been used extensively over the last two decades. Extensive research has been carried out to investigate solutions to enhance the lateral stability of pile foundations. This research is motivated by the need to install piles in sites characterized by soft subsurface soil conditions, and often times, in seismic active areas. This research work explores an innovative use of geosynthetics to enhance the lateral performance of pile foundations. The static and seismic soil-structure-interaction behaviors of geosynthetics-reinforced pile foundation systems were evaluated using a series of reduced scale physical model tests performed on a shaking table in a 1G environment. A laminar shear box containing a pile foundation model supporting a single degree of freedom structure installed in different soil bed models was used in the experiments. The soil models included: a layer of synthetic clay (Modified Glyben) underlain by a sand layer (simulating a base case of soft soil); a layer of synthetic clay sandwiched between a sand layer and an aggregate layer (simulating the case of conventional ground replacement for the top soft soil); and a layer of synthetic clay sandwiched between a sand layer and a geosynthetic-reinforced aggregate layer (simulating the case of ground replacement of the top soft soil combined with geosynthetic reinforcement using a microgrid mesh). A series of sine-sweep, harmonic and scaled earthquake tests have been performed to identify the amplification and resonance conditions of the foundation system and to identify various aspects of seismic-soil-pile-geosynthetic reinforcement interaction effects. Lateral static load tests of this system were performed using a one directional load system that was fixed on the laminar shear box. The dynamic and static tests were simulated employing numerical models developed using the finite element program Plaxis 3D. The results of both static and dynamic tests showed that the microgrid reinforcement improved the lateral performance of the pile foundation and reduced the vibration amplitudes of the supported structure. The numerical analysis results were in close agreement with the dynamic and static experimental results. The results of a parametric study for the investigated foundation configuration and seismic loading demands showed that the requirements for engineered backfill can be reduced by more than 50% and the lateral seismic response can be reduced by 50% by using geosynthetic reinforcement

Experimental investigations of natural circulation in a separate-and-mixed effects test facility mimicking prismatic modular reactor (PMR) core

After the Fukushima Daiichi nuclear power plant accident in 2011, significant attention was directed to investigate natural circulation thermal-hydraulics in Prismatic Modular Reactors (PMRs). Natural circulation is employed as a passive safety feature that passively removes the decay heat released after the loss of flow accidents (LOFA). Several computational studies have addressed such phenomena, however, validation of Computational Fluid Dynamics (CFD) is needed by providing high-quality data obtained from separate test facilities designed with reference to the corresponding reference PMRs. To address this need, a separate effects Plenum-to-Plenum Facility (P2PF) was designed and developed with dual channels and plena for experimental investigations of naturally driven gas thermal and velocity fields under different circulation intensities. Thermal and velocity measurements have been characterized by implementation of advanced sophisticated measurement techniques such as: (1) the hot wire anemometry (HWA), (2) flush-mounted micro-foil sensors, and (3) thermocouples that are capable of providing local measurements at different axial and radials positions along both channels. These measurement techniques have been integrated in a novel way so that the thermocouple readings are not disturbed by the HWA sensor, and vice versa. This proposed work has a significant impact on advancing the knowledge and understanding of the plenum-to-plenum (P2P) natural circulation thermal-hydraulic phenomenon and provides high-quality benchmark data that are much needed for verification and validation (V&V) of computational fluid dynamics (CFD) models and codes. Therefore, computational simulations can be reliably used in designing PMRs passive safety systems and in safety analysis and assessment --Abstract, page iv

Essays on Policy Evaluation from an Environmental and a Regional Perspective

This dissertation consists of three essays, which explore how public policies influence household and firm behavior, and the impact policies could have on environmental outcomes. The essays examine how households respond to price-based policies, the impact information disclosure policies could have on environmental outcomes, and finally the influence of normative appeals and non-pecuniary strategies on behavioral outcomes. Understanding these adjustments in the behavior of the agents is particularly important for policy design and for legislators who intend maximize societal benefit. The first essay, titled Matchmaking Between Vehicle Miles Traveled and Fuel Economy: the Role of Gasoline Prices, studies a potential effect of gasoline prices that has been over- looked in the literature. Due to heterogeneity in demand for vehicle miles traveled (VMT), when gasoline prices increase, the increased cost of operating an inefficient vehicle are greater for households that drive more. Thus, in equilibrium, after an increase in the gasoline prices there should be a stronger matching from households, based on their VMT, to the fuel economy of the cars they own. Potentially, this matching effect could save 15% of US gasoline consumption, even with no effect on individual VMT and no effect on the vehicle fleet. Using confidential data from the National Highway Transportation Survey, the effect of higher gasoline prices on such assortative matching is estimated using a variety of econometric models. For all the different model specifications, the matching effect is significant and quite robust. This is the first study to analyze this re-allocation or matching effect. The second essay, titled Evaluating the Effectiveness of an Environmental Disclosure Policy: an Application to New South Wales, examines the impact of an environmental information disclosure policy on environmental outcomes. The main purpose of introducing an environmental information disclosure strategy is to reduce informational asymmetries and put pressure on firms to reduce emissions. This paper studies the impact of such a policy on air quality in New South Wales, Australia. A regression discontinuity design is employed and the results show that the pollutant concentration levels were not significantly affected after the implementation of the policy. Empirically, the estimates of the effects under the discontinuity-based Ordinary Lease Squares (OLS) model have the opposite sign for some of the pollutants relative to the estimates from the basic OLS model. Therefore, basing conclusions on the OLS results will engender incorrect inference. Discontinuity-based results are robust to different model specifications. The third essay, titled What Determines Citizen Trust: Evaluating the Impact of Campaigns Highlighting Government Reforms in Pakistan, explores how normative appeals and awareness campaigns could influence societal and political trust. This project is in collaboration with Musharraf Cyan and Michael K. Price. The purpose of this study is two-fold. Firstly, the impacts of exposure to violence and conflict on general levels of trust, measures of life-satisfaction, and attitudes towards formal and informal institutions are examined in the province of Khyber Pakhtunkhwa (KPK), Pakistan. Secondly, the impacts of targeted messages, which were designed to inform the citizens regarding new government reforms (aimed at increasing transparency, protecting and strengthening private property rights, and improving service delivery), on general levels of trust and attitudes towards institutions are studied. For the analysis an in-person survey was designed, which was conducted in randomly selected villages throughout KPK. Empirical results show that exposure to violence has a negative impact on trust and measures of life-satisfaction and has positive effects on formal institutions. The results also suggest that the awareness campaigns affected trust levels and perceptions about the quality of public services positively. Moreover when the eeffects are allowed to differ based on exposure to conflict, important heterogeneity is identified. The results are robust to different model specifications