Search results for "Shrinking"

Shrinking and boundedly complete Schauder frames in Fréchet spaces

2014

We study Schauder frames in Fréchet spaces and their duals, as well as perturbation results. We define shrinking and boundedly complete Schauder frames on a locally convex space, study the duality of these two concepts and their relation with the reflexivity of the space. We characterize when an unconditional Schauder frame is shrinking or boundedly complete in terms of properties of the space. Several examples of concrete Schauder frames in function spaces are also presented.

On a Non-periodic Shrinking Generator

2011

We present a new non-periodic random number generator based on the shrinking generator. The A-sequence is still generated using a LFSR, but the S-sequence is replaced by a finitely generated bi-ideal - a non-periodic sequence. The resulting pseudo-random sequence performs well in statistical tests. We show a method for the construction of an infinite number of finitely generated bi-ideals from a given A-sequence, such that the resulting sequence of the shrinking generator is nonperiodic. Further we prove the existence of what we call universal finitely generated bi-ideals that produce non-periodic words when used as the S-sequence of a shrinking generator for all non-trivial periodic A-sequ…

On the generator problem

1990

Healthy design and urban planning strategies, actions, and policy to achieve salutogenic cities

2018

Starting from a previous experience carried out by the working group “Building and Environmental Hygiene” of the Italian Society of Hygiene and Preventive Medicine (SItI), the aim of the present work is to define new strategic goals for achieving a “Healthy and Salutogenic City”, which will be useful to designers, local governments and public bodies, policy makers, and all professionals working at local health agencies. Ten key points have been formulated: 1. climate change and management of adverse weather events; 2. land consumption, sprawl, and shrinking cities; 3. tactical urbanism and urban resilience; 4. urban comfort, safety, and security perception; 5. strengths and weaknesses of ur…

Urban Governance in Latvia: Feeling Urban and Thinking Rural

2019

Urbanisation is affecting not only countries with high number of residents but also with small number. The aim of the research is to explore urbanisation and shrinking city tendencies in a country with small number of residents in the context of globalization and urbanisation. The “donut effect” will be explored in the capital city Riga and ten municipalities nearby. The main research question is to what extent can the classical understanding and perception of urbanisation be applied to small societies and countries, and what kind of effects does the urbanisation create in such dynamically developing countries. There are several interdependent problems, such as the new patterns of urban–rur…

Hydrothermal liquefaction of wood using a modified multistage shrinking-core model

2020

Abstract Wood liquefaction in hot compressed water is modeled using the hydrolysis of Cellulose, Hemicellulose, and Lignin. These three components are reacted under catalyst-free subcritical conditions in a temperature range from 553 K to 640 K, and the heating rate ranges from 2 K/min to 6 K/min. Using a simplified reaction scheme, water-soluble products 1 (WSP), Biocrude, char, and gas are generated through intermediates with each wood component. A modified multistage shrinking core model is employed to simulate biomass particle degradation. The reaction and kinetic regime of the hydrothermal liquefaction 2 (HTL) process are treated separately for each wood component. Although the lack of…

Numerical modeling and validation of hydrothermal liquefaction of a lignin particle for biocrude production

2021

Abstract Lignin liquefaction process under catalyst-free conditions in a temperature range from 573 K to 647 K is investigated with this mathematical model. Based on the theoretical understanding of the physical and chemical processes of the liquefaction process in subcritical temperatures, a comprehensive mathematical model for the decomposition of lignin by hydrolysis reaction pathway is developed on the results of a series of batch experiments. The model consists of four main sections. They are liquefaction of lignin particle, oily film, and inorganic (ash) layer formation behavior during the liquefaction, kinetic model to model further liquefaction process of initial products, and the l…

Assessing Field and Laboratory Calibration Protocols for the Diviner 2000 Probe in a Range of Soils with Different Textures

2016

Frequency domain reflectometry (FDR) downhole sensors have been increasingly used for soil moisture field monitoring because they allow measurement, even continuously, along a soil profile. Moreover, they can also be installed with minimal soil disturbance around the access tube. The objectives of the paper were to assess the field and laboratory calibration protocols for a FDR capacitance probe (Diviner 2000) for a range of soils characterized by different particle size distributions and shrink/swell potential and to propose a practical and effective protocol on the basis of undisturbed soil samples, accounting for soil shrinkage/swelling processes characterizing swelling clay soils. The e…

Planning to meet challenges in shrinking rural regions. Towards innovative approaches to local planning

2023

In this article we ask to what extent is current demographic development reflected in the present planning and policy practice of shrinking municipalities; whether there is a focus on strategies and measures for population growth; and, finally, to what extent do politicians and planners think we should change the way we plan based on the expected demographic changes. Our study illustrates how challenging it is for shrinking municipalities to break with established practices and modes of policy development and to adopt a more sustainable position. The ‘stigma’ of shrinking (Sousa & Pinho 2015) is at odds with the ideals of the local politicians. However, we find that the response in planning…

Aperiodicity in finitely generated bi-ideals and bounded bi-ideals

2014

Disertācijā pētīts aperiodiskums divu vienpusēji bezgalīgu vārdu klašu – galīgi ģenerētu biideālu un ierobežotu bi-ideālu – kontekstā. Gan galīgi ģenerētus bi-ideālus, gan ierobežotus biideālus ir ērti uzdot, izmantojot bāzes virkni. Ierobežotu bi-ideālu gadījumā tiek nofiksēta galīga vārdu kopa, no kuras tiek uzģenerēta bāzes virkne. Savukārt galīgi ģenerētu bi-ideālu gadījumā bāzes virkne ir periodiska, līdz ar to var uzskatīt, ka ir dota galīga bāze. Efektīvā ģenerēšana un zināmie aperiodiskuma nosacījumi kalpo par motivāciju apskatīt galīgi ģenerētu bi-ideālu potenciālo pielietojumu kriptogrāfijā – aperiodisku gadījuma skaitļu ģenerēšanā. Savukārt, ierobežoti bi-ideāli ir galīgi ģenerēt…