Aman Ullah
Datos Biográficos
| ID | 3624337 |
|---|---|
| NOMBRE | Aman Ullah |
| NOMBRES | Aman |
| APELLIDO | Ullah |
| FIRMA | ULLAH A |
| AFILIACIONES | University of California, Riverside |
| ORCID | 0000-0001-5050-845X |
| VERIFICADO | Sí |
| TOTAL DE OBRAS | 27 |
| TOTAL DE CITAS | 13 |
| TOTAL COMO AUTOR | 26 |
| TOTAL COMO EDITOR | 1 |
| PRIMER AÑO DE PUBLICACIÓN | 1974 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2026 |
| ÍNDICE H | 2 |
Displacement threatens local knowledge
In the context of human displacement, it is essential to study how local knowledge is reshaped, eroded, or transformed. This study sheds light on how wild plant reports are articulated after migration, retained, and kept; the research explores specifically the ethnobotanical knowledge linked to wild food plants of five ethnic communities, namely the Bettani, Ormur, Mehsud, and Miani populations living in the Gomal area of NW Pakistan, of which th…
Common-neighbor based overlapping community detection in complex networks
This study tackles the problem of detecting overlapping communities in complex networks, a task that continues to be challenging due to its NP-hard nature. To tackle this issue, existing overlapping community detection methods face substantial challenges, including accommodating numerous community memberships, effectively differentiating between overlapping and non-overlapping nodes, and most of the time not paying attention to the subtle communi…
Blockchain and big data-optimized supply chains as facilitators of eco-innovative firm performance
Exploring community detection methods and their diverse applications in complex networks
Cultural Homogenization Has Affected Palula Traditional Plant Foraging in Multilingual Chitral, Hindukush, NW Pakistan
Generalized kernel regularized least squares estimator with parametric error covariance
A two-step estimator of a nonparametric regression function via Kernel regularized least squares (KRLS) with parametric error covariance is proposed. The KRLS, not considering any information in the error covariance, is improved by incorporating a parametric error covariance, allowing for both heteroskedasticity and autocorrelation, in estimating the regression function. A two step procedure is used, where in the first step, a parametric error co…
Keeping their own and integrating the other
Background In multicultural societies, traditional knowledge among minorities faces several challenges. Minority groups often face difficult situations living in specific peripheral geographies and striving to retain their biocultural heritage, including medicinal plant knowledge and practices. Folk medicinal plant knowledge is a dynamic eco-cultural complex influenced by various environmental, socio-cultural, and political factors. Examining med…
Optimal forecast under structural breaks
This paper develops an optimal combined estimator to forecast out‐of‐sample under structural breaks. When it comes to forecasting, using only the postbreak observations after the most recent break point may not be optimal. In this paper, we propose a new estimation method that exploits the prebreak information. In particular, we show how to combine the estimator using the full‐sample (i.e., both the prebreak and postbreak data) and the estimator …
Forecasting Under Structural Breaks Using Improved Weighted Estimation
In forecasting a time series containing a structural break, it is important to determine how much weight can be given to the observations prior to the time when the break occurred. In this context, Pesaran et al . (2013) (PPP) proposed a weighted least squares estimator by giving different weights to observations before and after a break point for forecasting out‐of‐sample. We revisit their approach by introducing an improved weighted generalized…
Living With Terror Not Living in Terror
Problem and aim of the study: This study is set out to investigate the impact of misinterpretation of religious education on sectarian violence in District Hangu. Research methods: Primary data regarding religious education and its role in sectarian violence was collected through a semi-structured questionnaire. The sample size of 279 respondents from three selected villages of District Hangu was randomly selected through the proportional allocat…
Teacher Education
Purpose of the study: This article aims to critically discuss the standards-based approach to language teacher education which was very popular initially in Britain and later in other parts of the world where it started to be followed as an ideal model for language teacher education. Given its popularity, a need was identified to have a critical appraisal of this popular approach for the benefit of the relevant stakeholders. Methodology: For this…
Predicting the Innovative Work Behavior by Assessing Leadership Styles in a Higher Educational Context
Purpose of Study: The present study aimed to examine the leadership styles (transformational & transactional) in predicting the innovative work behavior of the teacher in higher educational institutions. Leadership is important in the transformation of attitude and behavior of followers towards assigned responsibilities, however, which style is more effective in this transformation process in the main theme of the present study. Methodology: To a…
Sociological Analysis of Education and Reduction in Family Size in Khyber Pakhtunkhwa-Pakistan
Purpose of the study: The present study examines the association between education and reduction in family size in district Peshawar. Methodology: The results are based on the data gathered from 384 sampled respondents belonging to 6 communities that included 3 each from rural and urban areas of District Peshawar. The chi-square test was applied for statistical analysis. Main Findings: The study found a positive trend among the sampled families t…
Modal regression for fixed effects panel data
Road and Transportation Lead to Better Health and Sustainable Destination Development in Host Community
Road and transportation plays a vital role in the sustainable development and prosperity of the area. This study investigates the impact of road and transportation on the health of the host community and its sustainable destination development. Data were collected from the host community and were analyzed through factor analysis and structure equation modeling to evaluate the in-hand data of the structural relationship. It is revealed that road a…
Exploring t he Relationship Between "Covid-19" Experiences and People's Health Anxiety
The current study aims to explore and investigate the relationship between the experiences of COVID-19 and health anxiety among people. The study design adopted in this study was cross-sectional and primary data were collected from 500 respondents through a structured questionnaire in District Mardan-Pakistan. Bivariate and Multivariate analyses were carried out for measuring the relationship between "COVID-19" experiences and health anxiety, whi…
Forecasting Equity Premium
The equity premium, return on equity minus return on risk-free asset, is expected to be positive. We consider imposing such positivity constraint in local historical average (LHA) in nonparametric kernel regression framework. It is also extended to the semiparametric single index model when multiple predictors are used. We construct the constrained LHA estimator via an indicator function which operates as “model-selection” between the unconstrain…
The Oxford Handbook Of Applied Nonparametric And Semiparametric Econometrics And Statistics
Local Linear GMM Estimation of Functional Coefficient IV Models With an Application to Estimating the Rate of Return to Schooling
We consider the local linear generalized method of moment (GMM) estimation of functional coefficient models with a mix of discrete and continuous data and in the presence of endogenous regressors. We establish the asymptotic normality of the estimator and derive the optimal instrumental variable that minimizes the asymptotic variance-covariance matrix among the class of all local linear GMM estimators. Data-dependent bandwidth sequences are also …
Why Does Growing up in an Intact Family during Childhood Lead to Higher Earnings during Adulthood in the United States
With a view to finding an explanation of the observed differences in adult annual earnings between workers raised in intact (INTACT) and non-intact families in the US labor market, this study tests two hypotheses. First, workers growing up in intact families during childhood earn more during their adulthood because they acquire more years of schooling, which in turn affect their wages positively. Second, intact family background acts as an instru…
Estimation and Forecasting of Dynamic Conditional Covariance
We propose a semiparametric conditional covariance (SCC) estimator that combines the first-stage parametric conditional covariance (PCC) estimator with the second-stage nonparametric correction estimator in a multiplicative way. We prove the asymptotic normality of our SCC estimator, propose a nonparametric test for the correct specification of PCC models, and study its asymptotic properties. We evaluate the finite sample performance of our test …
Semiparametric Estimator of Time Series Conditional Variance
We propose a new combined semiparametric estimator, which incorporates the parametric and nonparametric estimators of the conditional variance in a multiplicative way. We derive the asymptotic bias, variance, and normality of the combined estimator under general conditions. We show that under correct parametric specification, our estimator can do as well as the parametric estimator in terms of convergence rates; whereas under parametric misspecif…
Testing Conditional Uncorrelatedness
We propose a nonparametric test for conditional uncorrelatedness in multiple-equation models such as seemingly unrelated regressions (SURs), multivariate volatility models, and vector autoregressions (VARs). Under the null hypothesis of conditional uncorrelatedness, the test statistic converges to the standard normal distribution asymptotically. We also study the local power property of the test. Simulation shows that the test behaves quite well …
A bias-adjusted LM test of error cross-section independence
This paper proposes a bias‐adjusted version of Breusch and Pagan (1980) Lagrange multiplier (LM) test statistic of error cross‐section independence, in the case of panel models with strictly exogenous regressors and normal errors. The exact mean and variance of the test indicator of the LM test statistic are provided for the purpose of the bias‐adjustments. It is shown that the centring of the LM statistic is correct for fixed T and N. Importantl…
Estimation of Moments and Production Decisions Under Uncertainty
The purpose of this paper is to examine production decisions under output price uncertainty. Using a nonparametric estimation technique to estimate the first four moments of the unknown price distribution and applying duality, we provide a simple empirical framework for the analysis of supply and demand decisions under price uncertainty. The model is used to examine the importance of higher moments in the firm's production decisions and to invest…
Competitive Firm and the Theory of Input Demand under Price Uncertainty
Keeping their own and integrating the other
Background In multicultural societies, traditional knowledge among minorities faces several challenges. Minority groups often face difficult situations living in specific peripheral geographies and striving to retain their biocultural heritage, including medicinal plant knowledge and practices. Folk medicinal plant knowledge is a dynamic eco-cultural complex influenced by various environmental, socio-cultural, and political factors. Examining med…
Cultural Homogenization Has Affected Palula Traditional Plant Foraging in Multilingual Chitral, Hindukush, NW Pakistan
Why Does Growing up in an Intact Family during Childhood Lead to Higher Earnings during Adulthood in the United States
With a view to finding an explanation of the observed differences in adult annual earnings between workers raised in intact (INTACT) and non-intact families in the US labor market, this study tests two hypotheses. First, workers growing up in intact families during childhood earn more during their adulthood because they acquire more years of schooling, which in turn affect their wages positively. Second, intact family background acts as an instru…
Competitive Firm and the Theory of Input Demand under Price Uncertainty
The Consumption Function
SINCE the publication Friedman's A Theory Consumption Function (1957), a number papers have appeared testing the permanent income hypothesis (PIH). With only a few exceptions (see Singh & Drost, 1971; Singh, 1975), most the researchers have estimated permanent income through the application Cagan's (1956) or Koyck's (1954) distributed lag model.1 As is well known, this leads to a regression current consumption on personal disposable income (PDI) …
Estimation of Moments and Production Decisions Under Uncertainty
The purpose of this paper is to examine production decisions under output price uncertainty. Using a nonparametric estimation technique to estimate the first four moments of the unknown price distribution and applying duality, we provide a simple empirical framework for the analysis of supply and demand decisions under price uncertainty. The model is used to examine the importance of higher moments in the firm's production decisions and to invest…
A bias-adjusted LM test of error cross-section independence
This paper proposes a bias‐adjusted version of Breusch and Pagan (1980) Lagrange multiplier (LM) test statistic of error cross‐section independence, in the case of panel models with strictly exogenous regressors and normal errors. The exact mean and variance of the test indicator of the LM test statistic are provided for the purpose of the bias‐adjustments. It is shown that the centring of the LM statistic is correct for fixed T and N. Importantl…
Testing Conditional Uncorrelatedness
We propose a nonparametric test for conditional uncorrelatedness in multiple-equation models such as seemingly unrelated regressions (SURs), multivariate volatility models, and vector autoregressions (VARs). Under the null hypothesis of conditional uncorrelatedness, the test statistic converges to the standard normal distribution asymptotically. We also study the local power property of the test. Simulation shows that the test behaves quite well …
Semiparametric Estimator of Time Series Conditional Variance
We propose a new combined semiparametric estimator, which incorporates the parametric and nonparametric estimators of the conditional variance in a multiplicative way. We derive the asymptotic bias, variance, and normality of the combined estimator under general conditions. We show that under correct parametric specification, our estimator can do as well as the parametric estimator in terms of convergence rates; whereas under parametric misspecif…
Estimation and Forecasting of Dynamic Conditional Covariance
We propose a semiparametric conditional covariance (SCC) estimator that combines the first-stage parametric conditional covariance (PCC) estimator with the second-stage nonparametric correction estimator in a multiplicative way. We prove the asymptotic normality of our SCC estimator, propose a nonparametric test for the correct specification of PCC models, and study its asymptotic properties. We evaluate the finite sample performance of our test …
Why Does Growing up in an Intact Family during Childhood Lead to Higher Earnings during Adulthood in the United States
With a view to finding an explanation of the observed differences in adult annual earnings between workers raised in intact (INTACT) and non-intact families in the US labor market, this study tests two hypotheses. First, workers growing up in intact families during childhood earn more during their adulthood because they acquire more years of schooling, which in turn affect their wages positively. Second, intact family background acts as an instru…
Local Linear GMM Estimation of Functional Coefficient IV Models With an Application to Estimating the Rate of Return to Schooling
We consider the local linear generalized method of moment (GMM) estimation of functional coefficient models with a mix of discrete and continuous data and in the presence of endogenous regressors. We establish the asymptotic normality of the estimator and derive the optimal instrumental variable that minimizes the asymptotic variance-covariance matrix among the class of all local linear GMM estimators. Data-dependent bandwidth sequences are also …
The Oxford Handbook Of Applied Nonparametric And Semiparametric Econometrics And Statistics
Forecasting Equity Premium
The equity premium, return on equity minus return on risk-free asset, is expected to be positive. We consider imposing such positivity constraint in local historical average (LHA) in nonparametric kernel regression framework. It is also extended to the semiparametric single index model when multiple predictors are used. We construct the constrained LHA estimator via an indicator function which operates as “model-selection” between the unconstrain…
Living With Terror Not Living in Terror
Problem and aim of the study: This study is set out to investigate the impact of misinterpretation of religious education on sectarian violence in District Hangu. Research methods: Primary data regarding religious education and its role in sectarian violence was collected through a semi-structured questionnaire. The sample size of 279 respondents from three selected villages of District Hangu was randomly selected through the proportional allocat…
Teacher Education
Purpose of the study: This article aims to critically discuss the standards-based approach to language teacher education which was very popular initially in Britain and later in other parts of the world where it started to be followed as an ideal model for language teacher education. Given its popularity, a need was identified to have a critical appraisal of this popular approach for the benefit of the relevant stakeholders. Methodology: For this…
Predicting the Innovative Work Behavior by Assessing Leadership Styles in a Higher Educational Context
Purpose of Study: The present study aimed to examine the leadership styles (transformational & transactional) in predicting the innovative work behavior of the teacher in higher educational institutions. Leadership is important in the transformation of attitude and behavior of followers towards assigned responsibilities, however, which style is more effective in this transformation process in the main theme of the present study. Methodology: To a…
Sociological Analysis of Education and Reduction in Family Size in Khyber Pakhtunkhwa-Pakistan
Purpose of the study: The present study examines the association between education and reduction in family size in district Peshawar. Methodology: The results are based on the data gathered from 384 sampled respondents belonging to 6 communities that included 3 each from rural and urban areas of District Peshawar. The chi-square test was applied for statistical analysis. Main Findings: The study found a positive trend among the sampled families t…
Modal regression for fixed effects panel data
Road and Transportation Lead to Better Health and Sustainable Destination Development in Host Community
Road and transportation plays a vital role in the sustainable development and prosperity of the area. This study investigates the impact of road and transportation on the health of the host community and its sustainable destination development. Data were collected from the host community and were analyzed through factor analysis and structure equation modeling to evaluate the in-hand data of the structural relationship. It is revealed that road a…
Exploring t he Relationship Between "Covid-19" Experiences and People's Health Anxiety
The current study aims to explore and investigate the relationship between the experiences of COVID-19 and health anxiety among people. The study design adopted in this study was cross-sectional and primary data were collected from 500 respondents through a structured questionnaire in District Mardan-Pakistan. Bivariate and Multivariate analyses were carried out for measuring the relationship between "COVID-19" experiences and health anxiety, whi…
Optimal forecast under structural breaks
This paper develops an optimal combined estimator to forecast out‐of‐sample under structural breaks. When it comes to forecasting, using only the postbreak observations after the most recent break point may not be optimal. In this paper, we propose a new estimation method that exploits the prebreak information. In particular, we show how to combine the estimator using the full‐sample (i.e., both the prebreak and postbreak data) and the estimator …
Forecasting Under Structural Breaks Using Improved Weighted Estimation
In forecasting a time series containing a structural break, it is important to determine how much weight can be given to the observations prior to the time when the break occurred. In this context, Pesaran et al . (2013) (PPP) proposed a weighted least squares estimator by giving different weights to observations before and after a break point for forecasting out‐of‐sample. We revisit their approach by introducing an improved weighted generalized…
Generalized kernel regularized least squares estimator with parametric error covariance
A two-step estimator of a nonparametric regression function via Kernel regularized least squares (KRLS) with parametric error covariance is proposed. The KRLS, not considering any information in the error covariance, is improved by incorporating a parametric error covariance, allowing for both heteroskedasticity and autocorrelation, in estimating the regression function. A two step procedure is used, where in the first step, a parametric error co…
Keeping their own and integrating the other
Background In multicultural societies, traditional knowledge among minorities faces several challenges. Minority groups often face difficult situations living in specific peripheral geographies and striving to retain their biocultural heritage, including medicinal plant knowledge and practices. Folk medicinal plant knowledge is a dynamic eco-cultural complex influenced by various environmental, socio-cultural, and political factors. Examining med…
Exploring community detection methods and their diverse applications in complex networks
Cultural Homogenization Has Affected Palula Traditional Plant Foraging in Multilingual Chitral, Hindukush, NW Pakistan
Common-neighbor based overlapping community detection in complex networks
This study tackles the problem of detecting overlapping communities in complex networks, a task that continues to be challenging due to its NP-hard nature. To tackle this issue, existing overlapping community detection methods face substantial challenges, including accommodating numerous community memberships, effectively differentiating between overlapping and non-overlapping nodes, and most of the time not paying attention to the subtle communi…
Mathematics (13 obras) · Statistics (13 obras) · Econometrics (10 obras) · Economics (8 obras) · Estimator (7 obras) · Monetary Policy and Economic Impact (7 obras) · Nonparametric statistics (7 obras) · Psychology (7 obras) · Computer Science (6 obras) · Financial Risk and Volatility Modeling (5 obras)