Case studies and mathematical models of ecological speciation. 3: Ecotype formation in a Swedish snail

Abstract A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This paper presents a theoretical investigation into the potential of modifying the rotor prole of the limaçon machines in order to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference, and describe the volumetric relationships of the new machine. This paper sets out by introducing a background on the limaçon technology in a simple yet adequate fashion. The housing-rotor inference has been discussed from two different mathematical standpoints, i.e. the tangent method and the radial clearance method. The paper then introduces the volumetric relationship for the proposed modified machine and combines all the models produced in an optimisation endeavour to design the best machine for a given set of operating condition. Case studies of different fluid processing applications are considered to demonstrate the soundness of the proposed modifications and models. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favourable characteristics.

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Seasonality in ecology: Progress and prospects in theory

10.7287/peerj.preprints.27235 ◽

2019 ◽

Author(s):

Easton R White ◽

Alan Hastings

Keyword(s):

Population Dynamics ◽

Mathematical Models ◽

Case Studies ◽

Floquet Theory ◽

Theoretical Studies ◽

Ecological Context ◽

Childhood Diseases ◽

Ecological Processes ◽

Natural Systems

Seasonality is an important feature of essentially all natural systems but the consequences of seasonality have been vastly underappreciated. Early work emphasized the role of seasonality in driving cyclic population dynamics, but the consequences of seasonality for ecological processes are far broader. Yet, seasonality is often not explicitly included in either empirical or theoretical studies. Many aspects of ecological dynamics can only be understood when seasonality is included, ranging from the oscillations in the incidence of childhood diseases to the coexistence of species. Through several case studies, we outline what is now known about seasonality in an ecological context and set the stage for future efforts. We discuss approaches for incorporating seasonality in mathematical models, including Floquet theory. We argue, however, that these tools are still limited in scope and more approaches need to be developed.

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Scraping Airlines Bots: Insights Obtained Studying Honeypot Data

International Journal of Cyber Forensics and Advanced Threat Investigations ◽

10.46386/ijcfati.v2i1.23 ◽

2021 ◽

Vol 2 (1) ◽

pp. 3-28

Author(s):

Elisa Chiapponi ◽

Marc Dacier ◽

Onur Catakoglu ◽

Olivier Thonnard ◽

Massimiliano Todisco

Keyword(s):

Mathematical Models ◽

Case Studies ◽

Inaccurate Information ◽

Web Scraping ◽

Behavioural Patterns ◽

Travel Agencies ◽

The One ◽

Online Travel ◽

Online Travel Agencies ◽

At Will

Airline websites are the victims of unauthorised online travel agencies and aggregators that use armies of bots to scrape prices and flight information. These so-called Advanced Persistent Bots (APBs) are highly sophisticated. On top of the valuable information taken away, these huge quantities of requests consume a very substantial amount of resources on the airlines' websites. In this work, we propose a deceptive approach to counter scraping bots. We present a platform capable of mimicking airlines' sites changing prices at will. We provide results on the case studies we performed with it. We have lured bots for almost 2 months, fed them with indistinguishable inaccurate information. Studying the collected requests, we have found behavioural patterns that could be used as complementary bot detection. Moreover, based on the gathered empirical pieces of evidence, we propose a method to investigate the claim commonly made that proxy services used by web scraping bots have millions of residential IPs at their disposal. Our mathematical models indicate that the amount of IPs is likely 2 to 3 orders of magnitude smaller than the one claimed. This finding suggests that an IP reputation-based blocking strategy could be effective, contrary to what operators of these websites think today.

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GEOGRAPHICAL MODELING FOR ARCHAEOLOGY AND HISTORY: TWO CASE STUDIES

Advances in Complex Systems ◽

10.1142/s0219525911003384 ◽

2012 ◽

Vol 15 (01n02) ◽

pp. 1150008 ◽

Cited By ~ 4

Author(s):

ALAN WILSON

Keyword(s):

United States ◽

Mathematical Models ◽

Case Studies ◽

Spatial Interaction ◽

Interaction Model ◽

Urban System ◽

The United States ◽

Geographical Modeling ◽

The Impact

This paper explores the role of mathematical models in archaeology and history. Variants of a particular model — an entropy-maximizing spatial interaction model which also functions as a location model — are presented through two case studies. The first is an example from Archaeology which throws light on settlement sizes in the 9th and 8th century BC Greece; the second is from History and explores the evolution of the United States' urban system from 1790–1870 with particular reference to the impact of railways. The approach is essentially interdisciplinary and uses concepts from Geography, Economics, Physics and Ecology.

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Seasonality in ecology: Progress and prospects in theory

10.7287/peerj.preprints.27235v2 ◽

2019 ◽

Cited By ~ 1

Author(s):

Easton R White ◽

Alan Hastings

Keyword(s):

Population Dynamics ◽

Mathematical Models ◽

Case Studies ◽

Floquet Theory ◽

Theoretical Studies ◽

Ecological Context ◽

Childhood Diseases ◽

Ecological Processes ◽

Natural Systems

Seasonality is an important feature of essentially all natural systems but the consequences of seasonality have been vastly underappreciated. Early work emphasized the role of seasonality in driving cyclic population dynamics, but the consequences of seasonality for ecological processes are far broader. Yet, seasonality is often not explicitly included in either empirical or theoretical studies. Many aspects of ecological dynamics can only be understood when seasonality is included, ranging from the oscillations in the incidence of childhood diseases to the coexistence of species. Through several case studies, we outline what is now known about seasonality in an ecological context and set the stage for future efforts. We discuss approaches for incorporating seasonality in mathematical models, including Floquet theory. We argue, however, that these tools are still limited in scope and more approaches need to be developed.

Download Full-text