Estimation of Inverse Weibull Distribution Under Type-I Hybrid Censoring

The hybrid censoring is a mixture of Type I and Type II censoring schemes. This paper presents the statistical inferences of the Inverse Weibull distribution when the data are Type-I hybrid censored. First we consider the maximum likelihood estimators of the unknown parameters. It is observed that the maximum likelihood estimators can not be obtained in closed form. We further obtain the Bayes estimators and the corresponding highest posterior density credible intervals of the unknown parameters under the assumption of independent gamma priors using the importance sampling procedure. We also compute the approximate Bayes estimators using Lindley's approximation technique. We have performed a simulation study and a real data analysis in order to compare the proposed Bayes estimators with the maximum likelihood estimators.Comment: This paper is under review in the Austrian Journal of Statistics and will likely be published ther

Assessing public spending efficiency in 20 OECD countries

Mestrado em Economia Monetária e FinanceiraBeing allocated a large share of a country's GDP to the public spending, would rise the question of whether these resources are distributed and allocated in an efficient manner that leads the country to go through the growth enhancing economic path or not. This study is mainly going to follow Afonso, Schuknecht, and Tanzi (2005), aiming to look at the public expenditure of 20 OECD countries for the period 2009-2013, from the perspective of efficiency and assess if these developed countries are performing efficiently compared to each other. In order to evaluate the efficiency scores, Public Sector Performance (PSP) and Public Sector Efficiency (PSE) indicators were constructed and Data Envelopment Analysis was conducted. The results of these analyses show that the only country that performed on the efficiency frontier is Switzerland. The average input-oriented efficiency score is equal to 0.732. That is, on average countries could have reduced the level of public expenditure by 26.8% and still achieved the same level of public performance. The average output-oriented efficiency score is 0.769 denoting that on average the sample countries could have increased their performance by 23.1% by employing the same level of public expenditure

Euro area sovereign yields and the power of unconventional monetary policy

We assess the determinants of long-term sovereign yield spreads, vis-à-vis Germany, using a panel of 10 Euro area countries over the period 1999.01–2016.07 notably regarding the ECB’s conventional and unconventional monetary policies. Our findings indicate that the international risk, the bid-ask spread and real effective exchange rate increased the 10-year sovereign bond yield spreads, while sovereign ratings’ improvements decreased the spreads. Moreover, Longer-term Refinancing Operations and the Securities Market Program decreased the yield spreads. The overall announcements of the unconventional policies also significantly decreased the yield spreads, notably in the periphery countries.info:eu-repo/semantics/publishedVersio

Assessing public spending efficiency in 20 OECD countries

This study follows the framework of Afonso, Schuknecht, and Tanzi (2005), aiming to look at the public expenditure of 20 OECD countries for the period 2009-2013, from the per- spective of efficiency and assess if these developed countries are performing efficiently compared to each other. Public Sector Performance (PSP) and Public Sector Efficiency (PSE) indicators were constructed and Data Envelopment Analysis was conducted. The results show that the only country that performed on the efficiency frontier is Switzerland. The average input-oriented efficiency score is equal to 0.732. That is, on average countries could have reduced the level of public expenditure by 26.8% and still achieved the same level of public performance. The average output-oriented efficiency score is 0.769 denoting that on average the sample countries could have increased their performance by 23.1% by employing the same level of public expenditure

Euro area sovereign yields and the power of QE

We assess the determinants of long-term sovereign yield spreads using a panel of 10 Euro area countries over the period 1999.01–2016.07 notably regarding the ECB (standard and non-standard) quantitative easing measures. Our findings indicate that the international risk, the bid-ask spread and real effective exchange rate increased the 10-year sovereign bond yield spreads. Moreover, quantitative easing, notably Longer-term Refinancing Operations (LTROs), Targeted LTROs and the Securities Market Program decreased the yield spreads.info:eu-repo/semantics/publishedVersio

Sovereign bond yields spreads spillovers in the EMU

We study the sovereign bond market co-movements and spillovers within 10 EMU countries, the so-called “periphery” and “core” countries, during the period 1999:01 to 2016:07. Implementing Generalized Methods of Moments (GMM) within a panel setting and bivariate VAR analysis, we find that an increase in the lagged spreads of Italian and Austrian bonds negatively affect the spreads of the whole sample while the increase in the Irish, Portuguese, Belgian and French lagged yields increased the overall spreads. In the VAR analysis we find that spillover effects within the sample are mostly positive.info:eu-repo/semantics/publishedVersio

Numerical simulations of the critical diameter and flame stability for hydrogen flames

This study focuses on development and validation of a CFD model to simulate the critical nozzle diameter and stability limits for hydrogen non-premixed flames. The critical diameter represents the minimum nozzle size through which a flame will remain stable at all driving pressures. Flames will not blow-out at diameters equal to or greater than the critical diameter. Accurate simulation of this parameter is important to assess performance of thermally activated pressure relief devices (TPRD) during blowdown from a storage tank. Flame stability is considered for diameters and overpressures ranging from 0.1 mm to 2 mm and from 0.06 MPa to 20 MPa, respectively. The impact of turbulent Schmidt number Sct, on predicted critical diameter is discussed. The model was applied for lower pressures (0.001–0.005 MPa) to understand the pressure at which the flame becomes attached. Simulations of a safer approach to TPRD design are discussed

The effects of macroeconomic, fiscal and monetary policy announcements on sovereign bond spreads : an event Study from the EMU

We assess the impact of announcements corresponding to different fiscal and monetary policy measures on the 10-year sovereign bond yield spreads (relative to Germany) of the 10 EMU countries during the period 01:1999 - 07:2016. Implementing pooled and country-fixed effects OLS regressions, we find that the European Commission’s (EC) releases of the excessive deficit procedure significantly affect the yield spreads. The EC releases of higher debt and better budget balance forecasts contribute to the rise and the decline of spreads, respectively. Moreover, we find that the announcements of the ECB’s key interest rates together with the longer-term refinancing operations (LTROs) and the first covered bond purchase programme (CBPP1) negatively affect sovereign yield spreads in our sample of EMU countries.info:eu-repo/semantics/publishedVersio

A Customized ILP-Based Solver for Description Logic Reasoners

Artificial intelligence based systems are known for conveying knowledge through machines. This knowledge is often represented using logic representation languages. One of the well-known families of such languages is called Description Logic (DL) which formally reasons and represents knowledge on the concepts, roles and individuals of an application domain. DL reasoners have been evolving and upgraded through the years, however when it comes to handling more complicated ontologies with big values occurring in number restrictions, the current reasoners mostly fail to perform efficiently. One of the techniques used in DL reasoners is the so-called atomic decomposition technique which combines arithmetic and logical reasoning. This thesis presents a customized CPLEX-based solver for enhancing DL reasoners through optimizing the atomic decomposition technique. Furthermore, we provide evidence on how this method can improve the reasoning performance by optimizing atomic decomposition. For such purpose, an empirical evaluation of our system for a set of synthesized benchmarks is demonstrated

Nourodevelopmental follow-up in high-risk infants: Review article

Growing and developing are influenced by genetic, social and environmental factors and it's most important and initial phase step is formed of the early life of the fetus and infant. According to the world health organization, the incidence of preterm birth and low birth weight are increasing in most countries that most of it related to developing countries. Low birth weight (LBW) and preterm birth are one the most important causes of death in the world and therefore are considered as one of the major health problems that can affect growing and developing so that it can threaten public health. Advances in medical technology in recent decades at intensive care unit, increased survival of premature infants and high-risk specialist care is needed, but failed, to reduce the complications of premature birth but it couldn’t reduce complications of preterm birth. There is also an increased recognition of the potential disconnect between perinatal outcomes and long-term outcomes. The administration of oxygen and postnatal steroids are prime examples of interventions that may have immediate positive effects but negative long-term effects. Many premature babies will be encounter with mobility problems, cognitive, neurosensory impairments, cerebral palsy, cognitive and language delays, neuromotor developmental delay, blindness and hearing loss, behavioral and psychosocial disorders, learning difficulties and dysfunction in scholastic performances in the future. These disadvantages appear to persist into adulthood and therefore have broad implications for society. Without a doubt, one of the tragedies of the world is people with physical or mental damage caused by premature birth, many of these disorders are not early diagnosed and the prediction of long term complications of infants discharged from the NICU is difficult. Although nourodevelopmental follow-up of these babies is a necessary part of the neonatal assessment but there is no standard process for it. The present review article aims to introduce the care process and tools that is used for following-up these babies, also introduces the application of screening tools for neuro-developmental care