7,162 research outputs found
Rigorous justification of Taylor dispersion via center manifolds and hypocoercivity
Taylor diffusion (or dispersion) refers to a phenomenon discovered
experimentally by Taylor in the 1950s where a solute dropped into a pipe with a
background shear flow experiences diffusion at a rate proportional to ,
which is much faster than what would be produced by the static fluid if its
viscosity is . This phenomenon is analyzed rigorously using the
linear PDE governing the evolution of the solute. It is shown that the solution
can be split into two pieces, an approximate solution and a remainder term. The
approximate solution is governed by an infinite-dimensional system of ODEs that
possesses a finite-dimensional center manifold, on which the dynamics
correspond to diffusion at a rate proportional to . The remainder term
is shown to decay at a rate that is much faster than the leading order behavior
of the approximate solution. This is proven using a spectral decomposition in
Fourier space and a hypocoercive estimate to control the intermediate Fourier
modes.Comment: 37 pages, 0 figure
Hydrologic homogeneous regions using monthly Streamflow in Turkey
Cluster analysis of gauged streamflow records into homogeneous and robust regions is an important tool for the characterization of hydrologic systems. In this paper we applied the hierarchical cluster analysis to the task of objectively classifying streamflow data into regions encompassing similar streamflow patterns over Turkey. The performance of three standardization techniques was also tested, and standardizing by range was found better than standardizing with zero mean and unit variance. Clustering was carried out using Ward’s minimum variance method which became prominent in managing water resources with squared Euclidean dissimilarity measures on 80 streamflow stations. The stations have natural flow regimes where no intensive river regulation had occurred. A general conclusion drawn is that the zones having similar streamflow pattern were not be overlapped well with the conventional climate zones of Turkey; however, they are coherent with the climate zones of Turkey recently redefined by the cluster analysis to total precipitation data as well as homogenous streamflow zones of Turkey determined by the rotated principal component analysis. The regional streamflow information in this study can significantly improve the accuracy of flow predictions in ungauged watersheds
Rad51/Dmc1 paralogs and mediators oppose DNA helicases to limit hybrid DNA formation and promote crossovers during meiotic recombination
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. ACKNOWLEDGMENTS We are grateful to J ¨urg Kohli, Ramsay J. McFarlane, Paul Russell, Gerald R. Smith, Walter W. Steiner and the National BioResource Project (NBRP) Japan for providing strains and to C. Bryer for technical assistance. FUNDING Wellcome Trust [090767/Z/09/Z to M.C.W.]; College of Life Sciences and Medicine, University of Aberdeen [to A.L., in part]. Funding for open access charge: Wellcome TrustPeer reviewedPublisher PD
A failure of meiotic chromosome segregation in a fbh1Δ mutant correlates with persistent Rad51-DNA associations
Peer reviewedPublisher PD
Semantic-based decision support for remote care of dementia patients
This paper investigates the challenges in developing a semantic-based Dementia Care Decision Support System based on the non-intrusive monitoring of the patient's behaviour. Semantic-based approaches are well suited for modelling context-aware scenarios similar to Dementia care systems, where the patient's dynamic behaviour observations (occupants movement, equipment use) need to be analysed against the semantic knowledge about the patient's condition (illness history, medical advice, known symptoms) in an integrated knowledgebase. However, our research findings establish that the ability of semantic technologies to reason upon the complex interrelated events emanating from the behaviour monitoring sensors to infer knowledge assisting medical advice represents a major challenge. We attempt to address this problem by introducing a new approach that relies on propositional calculus modelling to segregate complex events that are amenable for semantic reasoning from events that require pre-processing outside the semantic engine before they can be reasoned upon. The event pre-processing activity also controls the timing of triggering the reasoning process in order to further improve the efficiency of the inference process. Using regression analysis, we evaluate the response-time as the number of monitored patients increases and conclude that the incurred overhead on the response time of the prototype decision support systems remains tolerable
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Echo state network for occupancy prediction and pattern mining in intelligent environment
Pattern analysis and prediction of sensory data is becoming an increasing scientific challenge and a massive economical interest supports the need for better pattern mining techniques. The aim of this paper is to investigate efficient mining of useful information from a sensor network representing an ambient intelligence environment. The goal is to extract and predict behavioral patterns of a person in his/her daily activities by analyzing the time series data representing the behaviour of the occupant, generated using occupancy sensors. There are various techniques available for analysis and prediction of a continuous time series signal. However, the occupancy signal is represented by a binary time series where only discrete values of a signal are available. To build the prediction model, recurrent neural networks are investigated. They are proven to be useful tools to solve the difficulties of the temporal relationships of inputs between observations at different time steps, by maintaining internal states that have memory. In this paper, a special form of recurrent neural network, the so-called Echo State Network (ESN) is used in which discrete values of time series can be well processed. Then, a model developed based on ESN is compared with the most popular recurrent neural net-works; namely Back Propagation Through Time (BPTT) and Real Time Recurrent Learning (RTRL). The results showed that ESN provides better prediction results compared with BPTT and RTRL. Using ESN, large datasets are learnt in only few minutes or even seconds. It can be concluded that ESN are efficient and valuable tools in binary time series prediction. The results presented in this paper are based on simulated data generated from a simulator representing a person in a 1 bedroom flat
Polydimethylsiloxane Substrates for passive UHFRFID Sensors
PDMS has previously shown to be a suitable substrate for UHF-RFID strain sensor tags due to their elastomer characteristics. However, PDMS has further properties such as polymer swelling which could be utilized in gas sensing. Macroporous PDMS sponges have been proposed as suitable substrates for passive gas sensors. Porous sponges were fabricated using sugar templates and their absorption capacity was investigated along with standard PDMS elastomers. Possible applications could include food package and air quality monitoring
Skin-Mounted RFID Sensing Tattoos for Assistive Technologies
UHF RFID technology is presented that can facilitate new passive assistive technologies. Tongue control for human computer interfaces is first discussed where a tag is attached to the hard palate of the mouth and the tag turn-on power is observed to vary in response to tongue proximity. Secondly, a stretchable tag is fabricated from Lycra fabric that
contains conducting silver fibres. The application of strain to the elastic tag again causes the required power at the reader to activate the tag to vary in proportion. This elastic tag is proposed as a temporary skin mounted strain gauge that could detect muscle twitch in the face or neck of an otherwise physically incapacitated person. Either design might be applied to the steering function of a powered wheelchair, or to facilitate the control of a computer mouse. Better than 3dB isolation is achieved in the tongue switching case and approximately 0.25dBm per percentage stretch is observed for the strain gauge
Passive wireless tags for tongue controlled assistive technology interfaces
Tongue control with low profile, passive mouth tags is demonstrated as a human–device interface by communicating values of tongue-tag
separation over a wireless link. Confusion matrices are provided to demonstrate user accuracy in targeting by tongue position. Accuracy is
found to increase dramatically after short training sequences with errors falling close to 1% in magnitude with zero missed targets. The
rate at which users are able to learn accurate targeting with high accuracy indicates that this is an intuitive device to operate. The
significance of the work is that innovative very unobtrusive, wireless tags can be used to provide intuitive human–computer interfaces
based on low cost and disposable mouth mounted technology. With the development of an appropriate reading system, control of assistive
devices such as computer mice or wheelchairs could be possible for tetraplegics and others who retain fine motor control capability of
their tongues. The tags contain no battery and are intended to fit directly on the hard palate, detecting tongue position in the mouth with
no need for tongue piercings
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SOCIAL STRUCTURE OF ACCUMULATION IN TURKEY (1963 – 2015)
This dissertation analyzes capitalism in Turkey during post-1963 period from social structure of accumulation (SSA) theory perspective. The SSA theory is a theory of interaction of institutions and capital accumulation over long run. This dissertation will be the first book length study on Turkey using SSA Theory approach. It will enrich the SSA literature by adding a case of Turkey, which is a developing country; and hence it will be another example that SSA framework can be extended outside of US.
I observe two different SSAs during the period of interest. The first one is Import Substitution Industrialization (ISI) SSA from 1963 to 1980, which I named after dominant economic policy of the era. Turkey had experienced a military coup d’état in 1960, and a new constitution had been established in 1961, which had shaped most of the political and economic institutions, as well as the ideology, of the time. Related with these, the first five-year development plan, which was effective by the very first day of 1963, changed Turkish economy significantly. Chapter 3 presents features of ISI SSA, along with factors that played role in construction, working, and demise of ISI SSA.
The second SSA is Neoliberal (NL) SSA from 1980 to 2015. There was a military coup d’état that took place in September 1980, which had dramatic effects on the institutional environment in Turkey. More importantly, in January of the same year, a new set of neoliberal economic policies was put in effect that brought some important changes to Turkish economy. Chapter 4 analyzes features of NL SSA. There are two important phenomena during NL SSA period that deserves in depth analysis: Islamization and highly volatile growth during 1990s. Islamization has been an important part of the ideology of NL SSA in Turkey. Chapter 5 discusses effects of Islamization on both labor-capital and within capital class struggles. Then Chapter 6 presents an econometric model that provides evidence for positive relationship between private investment growth volatility and political instability. This chapter argues that political instability, due to rapidly changing governments, can be one of the reasons of high volatility in gross domestic product growth rate during NL SSA period
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