scholarly journals Estimation of the Mechanical Recovery Potential of Spilled Oil at Sea Considering the Spatial Thickness Distribution

2020 ◽  
Vol 8 (5) ◽  
pp. 362
Author(s):  
Yunseon Choe ◽  
Hyeonuk Kim ◽  
Cheol Huh ◽  
Choong-Ki Kim ◽  
Meang-Ik Cho ◽  
...  
Keyword(s):  
Thickness Distribution ◽  
Estimation Methods ◽  
Residual Oil ◽  
Recovery Model ◽  
Recovery Potential ◽  
Response Planning ◽  
Planning Models ◽  
The Relationship ◽  
Spilled Oil ◽  
Mechanical Recovery

Recovery modeling and countermeasures for oil spilled at sea have been extensively researched, but research remains insufficient on recovery potential estimation methods. It is required to access the mechanical recovery potential by considering the relationship between oil behavior, environmental conditions, and the performance of clean-up activities. Two response-planning models were developed in this study. One is a spatially uniform recovery model for estimating recovery potential that reflects weathering, oil properties, and equipment efficiency. The other is a spatially nonuniform recovery model that considers not only the above characteristics but also local thickness reduction by skimming. A comparison between the two models and an analysis of their effects on response was carried out through the calculation using an accident scenario. It is possible to analyze the effect of the thin slicks, natural dissipation, and the quantification of deployable skimming systems with the spatially nonuniform recovery model. Finally, we analyzed interrelationships among residual oil volume on the sea, response time, and the number of skimming systems.

Using The Fully Modified M Method In Estimating The Effect Of Cultivated Area On Barley Production In Iraq For The Period 1970-2018

2020 ◽  
Vol 2020 (66) ◽  
pp. 101-110
Author(s):  
. Azhar Kadhim Jbarah ◽  
Prof Dr. Ahmed Shaker Mohammed
Keyword(s):  
Regression Model ◽  
Moving Average ◽  
Estimation Method ◽  
Estimation Methods ◽  
Autoregressive Moving Average ◽  
Moving Average Models ◽  
Error Terms ◽  
Relationship Of ◽  
The Relationship ◽  
Barley Crop

The research is concerned with estimating the effect of the cultivated area of barley crop on the production of that crop by estimating the regression model representing the relationship of these two variables. The results of the tests indicated that the time series of the response variable values is stationary and the series of values of the explanatory variable were nonstationary and that they were integrated of order one ( I(1) ), these tests also indicate that the random error terms are auto correlated and can be modeled according to the mixed autoregressive-moving average models ARMA(p,q), for these results we cannot use the classical estimation method to estimate our regression model, therefore, a fully modified M method was adopted, which is a robust estimation methods, The estimated results indicate a positive significant relation between the production of barley crop and cultivated area.

scholarly journals A Distribution for Instantaneous Failures

Stats ◽  
2019 ◽  
Vol 2 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Pedro L. Ramos ◽  
Francisco Louzada
Keyword(s):  
Residual Life ◽  
Likelihood Estimation ◽  
Estimation Methods ◽  
Mean Residual Life ◽  
Parameter Distribution ◽  
Coverage Probabilities ◽  
Instantaneous Failures ◽  
The Relationship ◽  
Mean Variance ◽  
New Distribution

A new one-parameter distribution is proposed in this paper. The new distribution allows for the occurrence of instantaneous failures (inliers) that are natural in many areas. Closed-form expressions are obtained for the moments, mean, variance, a coefficient of variation, skewness, kurtosis, and mean residual life. The relationship between the new distribution with the exponential and Lindley distributions is presented. The new distribution can be viewed as a combination of a reparametrized version of the Zakerzadeh and Dolati distribution with a particular case of the gamma model and the occurrence of zero value. The parameter estimation is discussed under the method of moments and the maximum likelihood estimation. A simulation study is performed to verify the efficiency of both estimation methods by computing the bias, mean squared errors, and coverage probabilities. The superiority of the proposed distribution and some of its concurrent distributions are tested by analyzing four real lifetime datasets.

scholarly journals A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production

2011 ◽  
Vol 68 (3) ◽  
pp. 528-536 ◽  
Author(s):  
Miguel Bernal ◽  
Yorgos Stratoudakis ◽  
Simon Wood ◽  
Leire Ibaibarriaga ◽  
Luis Valdés ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Environmental Variables ◽  
Egg Production ◽  
Stock Assessment ◽  
Production Model ◽  
Estimation Methods ◽  
Statistical Framework ◽  
Spatio Temporal ◽  
The Relationship ◽  
Made In

Abstract Bernal, M., Stratoudakis, Y., Wood, S., Ibaibarriaga, L., Uriarte, A., Valdés, L., and Borchers, D. 2011. A revision of daily egg production estimation methods, with application to Atlanto-Iberian sardine. 2. Spatially and environmentally explicit estimates of egg production. – ICES Journal of Marine Science, 68: . A spatially and environmentally explicit egg production model is developed to accommodate a number of assumptions about the relationship between egg production and mortality and associated environmental variables. The general model was tested under different assumptions for Atlanto-Iberian sardine. It provides a flexible estimator of egg production, in which a range of assumptions and hypotheses can be tested in a structured manner within a well-defined statistical framework. Application of the model to Atlanto-Iberian sardine increased the precision of the egg production time-series, and allowed improvements to be made in understanding the spatio-temporal variability in egg production, as well as implications for ecology and stock assessment.

scholarly journals Optimization of Superplastic Forming Process of AA7075 Alloy for the Best Wall Thickness Distribution

2021 ◽  
Vol 6 (4) ◽  
pp. 251-261
Author(s):  
Manh Tien Nguyen ◽  
Truong An Nguyen ◽  
Duc Hoan Tran ◽  
Van Thao Le
Keyword(s):  
Wall Thickness ◽  
Deformation Temperature ◽  
Numerical Optimization ◽  
Thickness Distribution ◽  
Superplastic Forming ◽  
Forming Process ◽  
Wall Thickness Distribution ◽  
Surface Method ◽  
Series Of Experiments ◽  
The Relationship

This work aims to optimize the process parameters for improving the wall thickness distribution of the sheet superplastic forming process of AA7075 alloy. The considered factors include forming pressure p (MPa), deformation temperature T (°C), and forming time t (minutes), while the responses are the thinning degree of the wall thickness ε (%) and the relative height of the product h*. First, a series of experiments are conducted in conjunction with response surface method (RSM) to render the relationship between inputs and outputs. Subsequently, an analysis of variance (ANOVA) is conducted to verify the response significance and parameter effects. Finally, a numerical optimization algorithm is used to determine the best forming conditions. The results indicate that the thinning degree of 13.121% is achieved at the forming pressure of 0.7 MPa, the deformation temperature of 500°C, and the forming time of 31 minutes.

Macroeconomic fundamentals, institutional quality and shadow economy in OIC and non-OIC countries

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shabeer Khan ◽  
Mohd Ziaur Rehman
Keyword(s):  
Shadow Economy ◽  
Random Effect ◽  
Generalized Method Of Moments ◽  
Institutional Quality ◽  
Estimation Methods ◽  
Full Sample ◽  
Content Type ◽  
Macroeconomic Fundamentals ◽  
Negative Effect ◽  
The Relationship

PurposeThe purpose of this paper is to analyze the relationship between macroeconomic fundamentals, intuitional quality and shadow economy.Design/methodology/approachBy utilizing data setspanning from 2004 to 2015 of 141 countries, the study has employed advanced panel technique, i.e. Generalized Method of Moments (GMM) method. In order to check consistency of the results, the study also used fixed effect and random effect for robustness.FindingsThe study finds that for the full sample, institutional quality has negative effect on shadow economy while macroeconomic fundaments effect shadow economy differently. After splitting the sample into Organization of Islamic Cooperation (OIC) and non-OIC countries subsamples, it observes same influence of macroeconomic fundaments and institutional quality on shadow economy, but the effect of macroeconomic fundaments and institutional quality on shadow economy is less observed for OIC countries. The results are found consistence by using different estimation methods.Originality/valueThe current literature has focused on estimating the size of shadow economy and literature linking the macroeconomic fundaments, institutional quality and shadow economy is scarce. Additionally, this study provides the evidence for cross comparison between OIC economies and non-OIC economies.

scholarly journals Far Away, So Close? The Role of Destructive Leadership in the Job Demands–Resources and Recovery Model in Emergency Telework

2020 ◽  
Vol 9 (11) ◽  
pp. 196 ◽  
Author(s):  
Valentina Dolce ◽  
Emilie Vayre ◽  
Monica Molino ◽  
Chiara Ghislieri
Keyword(s):  
Social Support ◽  
Structural Equation ◽  
Job Demands ◽  
Self Report ◽  
Destructive Leadership ◽  
Recovery Model ◽  
Cognitive Demands ◽  
Remote Workers ◽  
The Relationship

During the Covid-19 pandemic, people started teleworking intensively, which has led to some benefits in terms of economic continuity, but also some complaints. International teams of scholars have pointed out the new work-related challenges, underlining leaders’ role in successfully managing them. This study aimed at investigating the role of destructive leadership in the job demands–resources and recovery model during the Covid-19 pandemic. In detail, this study intended to assess (1) whether destructive leadership is positively associated with off-work-hours technology-assisted job demand (off-TAJD) and cognitive demands, as well as whether it decreases autonomy, (2) whether two demands—off-TAJD and cognitive demands—and two resources—social support and autonomy—are respectively negatively and positively related to recovery, and (3) whether recovery mediates the relationship between demands, resources, and exhaustion. A total of 716 French remote workers (61% were women) took part in this study. Data were collected using a self-report questionnaire. A multi-group structural equation model was used to test the hypotheses. The findings confirmed a significant association between destructive leadership, the two job demands, and autonomy; furthermore, all three variables mediated the relationship between destructive leadership and recovery. The findings showed the key role played by recovery as a mediator between, on one hand, off-TAJD, cognitive demands, autonomy, and social support, and, on the other hand, exhaustion. This study highlighted the role of destructive leadership, job resources, job demands, and recovery as determinants of exhaustion, illustrating their relationships in a sample of remote workers. Practical implications are discussed.

Estimating Labour Supply in Policy-Oriented Regional Planning Models

1992 ◽  
Vol 24 (12) ◽  
pp. 1781-1797 ◽  
Author(s):  
D E Fuller
Keyword(s):  
Population Structure ◽  
Regional Planning ◽  
Labour Supply ◽  
Traditional Approach ◽  
Labour Force ◽  
Labour Demand ◽  
Regional Models ◽  
Demand And Supply ◽  
Planning Models ◽  
The Relationship

The importance of integrating policies concerned with the demand and supply of labour within growing regions has long been recognized. However, there are important theoretical deficiencies associated with orthodox methods. In the traditional approach to operational urban and regional models it is claimed that the relationship between labour demand and labour supply is functional and one sided, that is, the growth of labour demand causes population growth and leads to an assured level of labour supply. However it is argued that in the development of regional labour-force policies aimed at recognized objectives, estimates of the number and characteristics of persons available to the labour force are at least as important as estimates of the structure of labour demand. A change in the traditional theoretical framework is therefore necessary to allow for the influence of a particular population structure upon the supply of labour—in aggregate as well as to different occupational submarkets. Presentation of a more independent treatment of methods aimed at estimating the ‘availability’ (and the ‘requirements’) of labour also allows for the possibility, and consequences, of imbalance in the labour market to be recognized.

THE DYNAMIC INTER-RELATIONSHIP BETWEEN OBESITY AND SCHOOL PERFORMANCE: NEW EMPIRICAL EVIDENCE FROM AUSTRALIA

2017 ◽  
Vol 50 (5) ◽  
pp. 683-705 ◽  
Author(s):  
Son Nghiem ◽  
Viet-Ngu Hoang ◽  
Xuan-Binh Vu ◽  
Clevo Wilson
Keyword(s):  
School Performance ◽  
Simultaneous Equation ◽  
Estimation Methods ◽  
Reasoning Test ◽  
Obesity Status ◽  
The Matrix ◽  
Lagged Effects ◽  
Matrix Reasoning ◽  
National Tests ◽  
The Relationship

SummaryThis paper proposes a new empirical model for examining the relationship between obesity and school performance using the simultaneous equation modelling approach. The lagged effects of both learning and health outcomes were included to capture both the dynamic and inter-relational aspects of the relationship between obesity and school performance. The empirical application of this study used comprehensive data from the first five waves of the Longitudinal Study of Australian Children (LSAC), which commenced in 2004 (wave 1) and was repeated every two years until 2018. The study sample included 10,000 children, equally divided between two cohorts (infants and children) across Australia. The empirical results show that past learning and obesity status are strongly associated with most indicators of school outcomes, including reading, writing, spelling, grammar and numeracy national tests, and scores from the internationally standardized Peabody Picture Vocabulary Test and the Matrix Reasoning Test. The main findings of this study are robust due to the choice of obesity indicator and estimation methods.

scholarly journals Rest, Zest, and My Innovative Best: Sleep and Mood as Drivers of Entrepreneurs’ Innovative Behavior

2018 ◽  
Vol 43 (3) ◽  
pp. 582-610 ◽  
Author(s):  
Amanda J. Williamson ◽  
Martina Battisti ◽  
Michael Leatherbee ◽  
J. Jeffrey Gish
Keyword(s):  
Sleep Quality ◽  
Structural Equation ◽  
Equation Model ◽  
Innovative Behavior ◽  
Recovery Model ◽  
High Activation ◽  
Data Points ◽  
Multilevel Structural Equation ◽  
The Relationship ◽  
Multilevel Structural Equation Model

This study investigates the antecedents of an entrepreneur’s day-level innovative behavior. Drawing on 2,420 data points from a 10-day experience sampling study with 121 entrepreneurs, we find that sleep quality is a precursor to an entrepreneur’s subsequent innovative behavior, in accordance with the effort-recovery model. Moreover, sleep quality is positively related to high-activation positive moods (e.g., enthusiastic, inspired) and negatively related to high-activation negative moods (e.g., tension, anxiety). Our multilevel structural equation model indicates that high-activation positive moods mediate the relationship between sleep quality and innovative behavior on a given day. These results are relevant for managing entrepreneurial performance.

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