Search results1 – 10 of 339
In this paper, we study partial identification of the distribution of treatment effects of a binary treatment for ideal randomized experiments, ideal randomized…
In this paper, we study partial identification of the distribution of treatment effects of a binary treatment for ideal randomized experiments, ideal randomized experiments with a known value of a dependence measure, and for data satisfying the selection-on-observables assumption, respectively. For ideal randomized experiments, (i) we propose nonparametric estimators of the sharp bounds on the distribution of treatment effects and construct asymptotically valid confidence sets for the distribution of treatment effects; (ii) we propose bias-corrected estimators of the sharp bounds on the distribution of treatment effects; and (iii) we investigate finite sample performances of the proposed confidence sets and the bias-corrected estimators via simulation.
In this project, we propose and test a new device – wearable sociometric badges containing small microphones – as a low-cost and relatively unobtrusive tool for measuring…
In this project, we propose and test a new device – wearable sociometric badges containing small microphones – as a low-cost and relatively unobtrusive tool for measuring stress response to group processes. Specifically, we investigate whether voice pitch, measured using the microphone of the sociometric badge, is associated with physiological stress response to group processes.
We collect data in a laboratory setting using participants engaged in two types of small-group interactions: a social interaction and a problem-solving task. We examine the association between voice pitch (measured by fundamental frequency of the participant’s speech) and physiological stress response (measured using salivary cortisol) in these two types of small-group interactions.
We find that in the social task, participants who exhibit a stress response have a statistically significant greater deviation in voice pitch (from their overall average voice pitch) than those who do not exhibit a stress response. In the problem-solving task, participants who exhibit a stress response also have a greater deviation in voice pitch than those who do not exhibit a stress response, however, in this case, the results are only marginally significant. In both tasks, among participants who exhibited a stress response, we find a statistically significant correlation between physiological stress response and deviation in voice pitch.
Practical and research implications
We conclude that wearable microphones have the potential to serve as cheap and unobtrusive tools for measuring stress response to group processes.
This paper uses data from the 1979 and 1997 National Longitudinal Surveys of Youth to estimate the changing returns to cognitive and non-cognitive skills with respect to…
This paper uses data from the 1979 and 1997 National Longitudinal Surveys of Youth to estimate the changing returns to cognitive and non-cognitive skills with respect to college completion, and quantifies the extent to which gender differences in these skills are driving the college gender gap. The use of two distinct college graduation cohorts allows a dynamic analysis of the widening female advantage in college graduation. I decompose the increase in the college gender gap into three pertinent categories of measurable attributes: family background, cognitive skills, and non-cognitive skills (captured by school suspensions, behavioral problems, and legal infractions). A second decomposition is applied to the change in the gap between the two periods. The results show that roughly half of the observed college graduation gender gap in the NLSY97 is due to female advantages in observable characteristics, and roughly half is “unexplained”: due to gender differences in the coefficients. With respect to the change in the gap, approximately 29% of the difference in differences is the “explained” component, attributed to changes in the relative characteristics of men and women. In particular, declining non-cognitive skills in men are associated with about 14% of the increase in the gender gap.
Continuous Sampling Plans (CSP) are used where processes are continuous and products are not grouped into lots. The principal design criterion for these plans is the…
Continuous Sampling Plans (CSP) are used where processes are continuous and products are not grouped into lots. The principal design criterion for these plans is the Average Outgoing Quality Limit (AOQL), which is the worst outgoing quality over all possible values of the incoming quality level. These are generally applicable to in‐process and final inspections and have been found to be most effective when administered in such a way as to provide an incentive to clear up the faults promptly. In applying the traditional continuous sampling plans, it is necessary to revert to 100 per cent inspection when the quality deteriorates. Therefore, the inspection rate must be larger than production rate and the unit inspection cost must be low. The plan presented in this article relaxes the 100 per cent inspection restriction while reaching the same AOQL quality assurance as traditional CSP‐1. The Markov chain process and numerical analysis will be used to formulate the plan. Its results are then evaluated against CSP‐2.
Novel necessary and sufficient existence conditions for convolution inverses of real finite sequences are derived. These conditions are obtained with the aid of well known…
Novel necessary and sufficient existence conditions for convolution inverses of real finite sequences are derived. These conditions are obtained with the aid of well known conditions expressed in terms of the Fourier and z‐transforms. The conditions given in the paper imply suitable algorithms, which are convenient for checking the existence of convolution inverses of any real finite sequences.
The Gulf Cooperation Council member countries not only generate the highest quantity of municipal solid waste (MSW) per capita when compared globally, but also in most of…
The Gulf Cooperation Council member countries not only generate the highest quantity of municipal solid waste (MSW) per capita when compared globally, but also in most of these countries, such waste is just dumped at different landfill stations. In Oman, the total quantity of MSW stood at 2.0 million tons per year. The emission from this waste is estimated at 2,181,034 tons/year (carbon dioxide equivalent). This article attempts to develop frameworks that considered landfilling, composting and recycling of MSW.
To know the composition of the municipal solid waste in Oman, a quantitative research method was employed. The greenhouse gas (GHG) emissions from MSWM in this study focus on three major gases, CO2, CH4 and N2O. The Intergovernmental Panel on Climate Change (IPCC) 2006 model is used to calculate GHG emissions from landfills and composting (IPCC, 2006). Four frameworks – baseline F0, framework F1, framework F2 and framework F3 – are outlined in this paper. The F0 represents the current situation of the MSW in which most of the waste goes to landfills and dumpsites. In F1, improved MSW collection service and landfilling are incorporated and open burning is restricted. The F2 considered landfilling and composting, while F3 is based on landfilling, composting and recycling.
The framework F2, which proposes the composting process for the organic waste which normally goes to landfills, results in the reduction of emissions by 40% as compared to landfill practice. Similarly, the samples of MSW collected in Oman show a good amount of recycling waste. The framework F3, which considers the landfill, composting and recycling, reduced the total GHG emissions from 2,181,034 tons/year to 1,427,998 tons/year (carbon dioxide equivalent), representing a total reduction of 35% in emissions.
Different values such as CH4 correction factor, the fraction of degradable organic carbon and the fraction of DOC used to determine the GHG emissions from MSW considering landfilling, composting and recycling based on the IPPC model and existing literature review. The actual determination of these values based on the Oman conditions may result in more accurate emissions from MSW in Oman.
Different frameworks suggested in this research have different practical implications; however, the final framework F3, which produces fewer emissions, required a material recovery facility to recycle the MSW in Oman. For framework F3, it is important that the residents in Oman have enough knowledge and willingness to do the waste segregation at the household level. Apparently, such knowledge and willingness need to be determined through a separate study.
The frameworks F2 and F3 are considered to be more suitable solutions compared to the current practices for Oman and other gulf countries to reduce its per capita emissions from MSW and protect its local environment. There is a potential for further work that needs to explore the possible solutions to implement the suggested frameworks.
Shannon’s entropy is usually defined separately for discrete, and for (absolutely) continuous random variables. However, many random variables encountered in practice have…
Shannon’s entropy is usually defined separately for discrete, and for (absolutely) continuous random variables. However, many random variables encountered in practice have mixed (discrete‐continuous) distributions. A simple expression for the entropy of random variables with mixed (discrete‐continuous) distributions is derived in terms of the usual entropy definitions. In addition, the maximum entropy problem in the general setting of mixture distributions is discussed.
The entropy as a measure of diversity has been used by ecologists to characterize a community by its stability process. After the introduction of the concept of a fuzzy…
The entropy as a measure of diversity has been used by ecologists to characterize a community by its stability process. After the introduction of the concept of a fuzzy subset by Zadeh (1965), many definitions of entropies were given emphasizing the subjectivity in evaluations. A pioneering work which relates the classical meaning of entropy (Shannon index) with the modern fuzzy theory was due to De Luca and Termini (1972); Knopfmacher (1975) formulated a generalization of the axiomatics given by De Luca and Termini; Batle and Trillas (1979) obtained a result which is essentially analogous to Knopfmacher’s by considering a finite fuzzy measure space and the Sugeno’s integrals; and Trillas and Riera (1978) introduced the concept of fuzzy algebraic entropics. Analyses the continuity properties for these fuzzy entropies and establishes conditions which guarantee the convergence E(fn) → E(f), where (fn) is a sequence of fuzzy sets and E is an entropy.
In this work we outline the methodology by which the Wigner Distribution Function (WDF) may be applied to the simulation of field emission from silicon into the vacuum so…
In this work we outline the methodology by which the Wigner Distribution Function (WDF) may be applied to the simulation of field emission from silicon into the vacuum so that the effects of self‐consistently calculated band bending and scattering on the current‐field characteristics may be assessed. For the first time, current saturation‐like effects are simulated. We analyze this in light of the behavior of the self‐consistent potential and density profiles at high applied fields.
Deals with the impact of anti‐terrorism initiatives on the operational areas of investigation and enforcement. Focuses first on investigation powers, such as power to…
Deals with the impact of anti‐terrorism initiatives on the operational areas of investigation and enforcement. Focuses first on investigation powers, such as power to restrain terrorist property, obtain a search warrant, require production and access to particular material and an explanation, require a financial institution provide customer information, monitor accounts, and assessment. Moves on to terrorist finance‐related offences, according to the Terrorism Act 2000 Part III, and mutual legal assistance; measuring success by the cost of mounting a terrorist campaign, and the impact of measures against terrorist finance; culture, including organisational culture and Special Branch culture; organisational structures, including cultural change, organisational change for intelligence gathering, disruption of illegal activity short of arrest, arrest and prosecution, and the impact of human rights legislation; resource management, ie staff dedicated to terrorist finance issues and a formal structure for dealing with it; and international cooperation after September 11.