scholarly journals From damage models to SIR epidemics and cascading failures

2009 ◽  
Vol 41 (1) ◽  
pp. 247-269 ◽  
Author(s):  
Maude Gathy ◽  
Claude Lefèvre
Keyword(s):  
Branching Process ◽  
Damage Model ◽  
Exact Distribution ◽  
Partial Sums ◽  
Mathematical Tool ◽  
Close Approximation ◽  
Final Size ◽  
Damage Models ◽  
Starting Point ◽  
Made In

This paper is concerned with a nonstationary Markovian chain of cascading damage that constitutes an iterated version of a classical damage model. The main problem under study is to determine the exact distribution of the total outcome of this process when the cascade of damages finally stops. Two different applications are discussed, namely the final size for a wide class of SIR (susceptible → infective → removed) epidemic models and the total number of failures for a system of components in reliability. The starting point of our analysis is the recent work of Lefèvre (2007) on a first-crossing problem for the cumulated partial sums of independent parametric distributions, possibly nonstationary but stable by convolution. A key mathematical tool is provided by a nonstandard family of remarkable polynomials, called the generalised Abel–Gontcharoff polynomials. Somewhat surprisingly, the approach followed will allow us to relax some model assumptions usually made in epidemic theory and reliability. To close, approximation by a branching process is also investigated to a certain extent.

scholarly journals From damage models to SIR epidemics and cascading failures

2009 ◽  
Vol 41 (01) ◽  
pp. 247-269 ◽  
Author(s):  
Maude Gathy ◽  
Claude Lefèvre
Keyword(s):  
Branching Process ◽  
Damage Model ◽  
Exact Distribution ◽  
Partial Sums ◽  
Mathematical Tool ◽  
Close Approximation ◽  
Final Size ◽  
Damage Models ◽  
Starting Point ◽  
Made In

This paper is concerned with a nonstationary Markovian chain of cascading damage that constitutes an iterated version of a classical damage model. The main problem under study is to determine the exact distribution of the total outcome of this process when the cascade of damages finally stops. Two different applications are discussed, namely the final size for a wide class of SIR (susceptible → infective → removed) epidemic models and the total number of failures for a system of components in reliability. The starting point of our analysis is the recent work of Lefèvre (2007) on a first-crossing problem for the cumulated partial sums of independent parametric distributions, possibly nonstationary but stable by convolution. A key mathematical tool is provided by a nonstandard family of remarkable polynomials, called the generalised Abel–Gontcharoff polynomials. Somewhat surprisingly, the approach followed will allow us to relax some model assumptions usually made in epidemic theory and reliability. To close, approximation by a branching process is also investigated to a certain extent.

Quel corpus pour l’étude du dialecte niçois ?

2021 ◽  
Vol 137 (2) ◽  
pp. 344-361
Author(s):  
Philippe Del Giudice
Keyword(s):  
Middle Ages ◽  
Written Language ◽  
Linguistic Features ◽  
Descriptive Grammar ◽  
Written Production ◽  
Starting Point ◽  
Social Use ◽  
Over Time ◽  
Made In ◽  
Do So

Abstract A new project has just been launched to write a synchronic, descriptive grammar of Niçois, the Occitan dialect of Nice. In this article, I define the corpus of the research. To do so, I first review written production from the Middle Ages to the present. I then analyze the linguistic features of Niçois over time, in order to determine the precise starting point of the current language state. But because of reinforced normativism and the decreasing social use of Niçois among the educated population, written language after WWII became artificial and does not really correspond to recordings made in the field. The corpus will thus be composed of writings from the 1820’s to WWII and recordings from the last few decades.

Failure Predictions for DP Steel Cross-die Test using Anisotropic Damage

2011 ◽  
Vol 21 (5) ◽  
pp. 713-754 ◽  
Author(s):  
M. S. Niazi ◽  
H. H. Wisselink ◽  
T. Meinders ◽  
J. Huétink
Keyword(s):  
Strain Rate ◽  
Damage Evolution ◽  
Damage Model ◽  
Anisotropic Damage ◽  
Continuum Damage ◽  
Anisotropic Plasticity ◽  
Continuum Damage Model ◽  
Damage Models ◽  
Isotropic Damage ◽  
Failure Predictions

The Lemaitre's continuum damage model is well known in the field of damage mechanics. The anisotropic damage model given by Lemaitre is relatively simple, applicable to nonproportional loads and uses only four damage parameters. The hypothesis of strain equivalence is used to map the effective stress to the nominal stress. Both the isotropic and anisotropic damage models from Lemaitre are implemented in an in-house implicit finite element code. The damage model is coupled with an elasto-plastic material model using anisotropic plasticity (Hill-48 yield criterion) and strain-rate dependent isotropic hardening. The Lemaitre continuum damage model is based on the small strain assumption; therefore, the model is implemented in an incremental co-rotational framework to make it applicable for large strains. The damage dissipation potential was slightly adapted to incorporate a different damage evolution behavior under compression and tension. A tensile test and a low-cycle fatigue test were used to determine the damage parameters. The damage evolution was modified to incorporate strain rate sensitivity by making two of the damage parameters a function of strain rate. The model is applied to predict failure in a cross-die deep drawing process, which is well known for having a wide variety of strains and strain path changes. The failure predictions obtained from the anisotropic damage models are in good agreement with the experimental results, whereas the predictions obtained from the isotropic damage model are slightly conservative. The anisotropic damage model predicts the crack direction more accurately compared to the predictions based on principal stress directions using the isotropic damage model. The set of damage parameters, determined in a uniaxial condition, gives a good failure prediction under other triaxiality conditions.

scholarly journals Treatments’ Complexity in Dental Care Assistance, Urban Versus Rural Environment - Preliminary Study

2021 ◽  
Vol 26 (1) ◽  
pp. 75-78
Author(s):  
Camelia Ionescu ◽  
Mădălina Adriana Malița ◽  
Viorel Ștefan Perieanu ◽  
Mihai Burlibașa ◽  
Magdalena Natalia Dina ◽  
...  
Keyword(s):  
Dental Care ◽  
Urban Areas ◽  
Rural Environment ◽  
Facial Region ◽  
Starting Point ◽  
Preliminary Study ◽  
Dental Offices ◽  
Care Assistance ◽  
Urban Versus ◽  
Made In

Abstract When talking about dental assistance we actually refer to the prevention, detection and treatment of diseases of the oral and maxillo-facial region which, in most cases, have as a starting point or interest the dento-maxillary system. In this material, we tried to present a comparative study on the typology and complexity of different stages of dental treatments that can be performed in urban areas, compared to various stages of dental treatments that are performed and / or could be made in rural dental offices from in Romania.

scholarly journals Otras imágenes y otras palabras de la Transición española

Neuróptica ◽  
2020 ◽  
pp. 103-118
Author(s):  
Pablo Dopico
Keyword(s):  
Democratic Transition ◽  
Multidisciplinary Approach ◽  
Historical Document ◽  
Starting Point ◽  
Joint Study ◽  
Siglo Xx ◽  
Direct Reflection ◽  
Made In

Resumen: Desde un enfoque inter y multidisciplinar, el estudio conjunto de la obra de Eduardo Haro Ibars, Alberto García-Alix y Ceesepe se presenta como punto de partida para abordar algunos nexos y relaciones existentes entre el cómic underground, la fotografía y la poesía realizadas en la España de la Transición democrática. Con el objetivo de establecer vínculos entre el cómic y otras artes, este análisis pretende descubrir múltiples afinidades entre los tres autores y entre ambos lenguajes, el visual y el literario, reivindicando su valor como documento histórico de excepcional interés que ofrece un reflejo directo de los acontecimientos ocurridos en España entre la prometedora década de los setenta y el desencanto de los ochenta del pasado siglo XX. Abstract: From an inter and multidisciplinary approach, the joint study of the work of Eduardo Haro Ibars, Alberto García-Alix and Ceesepe is presented as a starting point to address some links and relationships between underground comics, photography and poetry made in the Spain of the democratic transition. With the aim of establishing links between the comic and other arts, this analysis aims to discover multiple affinities between the three authors and between both languages, the visual and the literary, claiming their value as a historical document of exceptional interest that offers a direct reflection of the events in Spain between the promising decade of the seventies and the disenchantment of the eighties of the last century.

scholarly journals Extension of Flow Behaviour and Damage Models for Cast Iron Alloys with Strain Rate Effect

2020 ◽  
Author(s):  
Chuang Liu ◽  
Dongzhi Sun ◽  
Xianfeng Zhang ◽  
Florence Andrieux ◽  
Tobias Gerster
Keyword(s):  
Cast Iron ◽  
Constitutive Model ◽  
Strain Rate ◽  
Mechanical Behavior ◽  
Damage Model ◽  
Iron Alloys ◽  
Strain Rate Range ◽  
Strain Rates ◽  
Damage Models ◽  
Rate Dependent

Abstract Cast iron alloys with low production cost and quite good mechanical properties are widely used in the automotive industry. To study the mechanical behavior of a typical ductile cast iron (GJS-450) with nodular graphite, uni-axial quasi-static and dynamic tensile tests at strain rates of 10− 4, 1, 10, 100, and 250 s− 1 were carried out. In order to investigate the effects of stress state, specimens with various geometries were used in the experiments. Stress–strain curves and fracture strains of the GJS-450 alloy in the strain-rate range of 10− 4 to 250 s− 1 were obtained. A strain rate-dependent plastic flow law based on the Voce model is proposed to describe the mechanical behavior in the corresponding strain-rate range. The deformation behavior at various strain rates is observed and analyzed through simulations with the proposed strain rate-dependent constitutive model. The available damage model from Bai and Wierzbicki is extended to take the strain rate into account and calibrated based on the analysis of local fracture strains. The validity of the proposed constitutive model including the damage model was verified by the corresponding experimental results. The results show that the strain rate has obviously nonlinear effects on the yield stress and fracture strain of GJS-450 alloys. The predictions with the proposed constitutive model and damage models at various strain rates agree well with the experimental results, which illustrates that the rate-dependent flow rule and damage models can be used to describe the mechanical behavior of cast iron alloys at elevated strain rates.

scholarly journals The tale of the fungi of two gardens: non-lichenised fungi of the Botanic Gardens in Glasgow

2019 ◽  
Vol 27 (1) ◽  
pp. 57-63
Author(s):  
R. Watling
Keyword(s):  
City Council ◽  
Complete List ◽  
Botanic Gardens ◽  
Short Account ◽  
Starting Point ◽  
History Of ◽  
Made In ◽  
Present Site

A brief history of the early days of mycology in Scotland is given to act as a starting point from which to view the fungal records made in the gardens at Sandyford and Kelvinside. The former was vacated in 1842 and the garden transferred to the present site at Kelvinside under the authority of the Glasgow City Council. The role of J.F. Klotzsch in generating the earliest records is emphasised and the compilation of fungal records, mainly of macrofungi, until the present day is discussed. A short account of the microfungi is given. A complete list of the fungi recorded from the two gardens is provided.

The asymptotic final size distribution of multitype chain-binomial epidemic processes

1999 ◽  
Vol 31 (01) ◽  
pp. 220-234 ◽  
Author(s):  
Mikael Andersson
Keyword(s):  
Branching Process ◽  
Counting Process ◽  
Contact Structure ◽  
Finite Population ◽  
Convergence Result ◽  
System Of Equations ◽  
Final Size ◽  
Linear System Of Equations ◽  
Non Linear System ◽  
Process Approximation

A multitype chain-binomial epidemic process is defined for a closed finite population by sampling a simple multidimensional counting process at certain points. The final size of the epidemic is then characterized, given the counting process, as the smallest root of a non-linear system of equations. By letting the population grow, this characterization is used, in combination with a branching process approximation and a weak convergence result for the counting process, to derive the asymptotic distribution of the final size. This is done for processes with an irreducible contact structure both when the initial infection increases at the same rate as the population and when it stays fixed.

Comparison of Two Damage Models for Prediction of Failure in Stress Corrosion Cracking

2018 ◽  
Author(s):  
Sorabh Singhal ◽  
Yogeshwar Jasra ◽  
Ravindra K. Saxena
Keyword(s):  
Crack Initiation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Driving Force ◽  
Damage Mechanics ◽  
Damage Model ◽  
Corrosion Cracking ◽  
Force Model ◽  
Initiation Time ◽  
Damage Models

In the present work, Stress corrosion cracking (SCC) and its mechanical behavior are presented. SCC represents complex behavior due to electrochemical and mechanical interaction. Damage models are proposed to predict crack initiation time for stainless steel under constant load using the concept of continuum damage mechanics to show incremental damage accumulation which finally leads to failure of the material. Two damage models applicable to prediction of damage in SCC, Lemaitre damage model and damage driving force model proposed by Kamaya are compared. The comparative study of the results obtained by these damage models shows that in Lemaitre damage law cracks initiate randomly while in damage driving force model the stress concentration occurs around the periphery of damaged element results in increased damage force. The study can be used to estimate the crack initiation time in SCC under corrosive atmosphere.

Mutual Value in Business Relationships

2010 ◽  
pp. 971-981
Author(s):  
Rita de Cássia Pereira ◽  
Carlo Gabriel Porto Bellini ◽  
Fernando Bins Luce
Keyword(s):  
Relationship Marketing ◽  
Value Creation ◽  
Business Relationships ◽  
Business Relationship ◽  
Research Fronts ◽  
Starting Point ◽  
Working Together ◽  
Relationship Assessment ◽  
Made In

Relationship marketing evolves both in quantity and quality, as we can tell from the continuous incorporation of new constructs, models and technologies, the myriad of applications in different contexts, and the interaction with other marketing and management areas. Concepts and processes in relationship marketing continue to mature significantly with the help of developments made in other research fronts. In this sense, the concept of value as communicated by authors in the field (e.g., Hogan, 2001; Möller & Törrönen, 2003) brought light to the problem of relationship assessment, if we agree that value creation is critical for companies working together in a business relationship (Walter et al., 2001); thus, value creation must be the starting point for companies and customers to assess their relationships.

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