Redox reactions with empirical potentials: Atomistic battery discharge simulations

Batteries are pivotal components in overcoming some of today's greatest technological challenges. Yet to date there is no self-consistent atomistic description of a complete battery. We take first steps toward modeling of a battery as a whole microscopically. Our focus lies on phenomena occurring at the electrode-electrolyte interface which are not easily studied with other methods. We use the redox split-charge equilibration (redoxSQE) method that assigns a discrete ionization state to each atom. Along with exchanging partial charges across bonds, atoms can swap integer charges. With redoxSQE we study the discharge behavior of a nano-battery, and demonstrate that this reproduces the generic properties of a macroscopic battery qualitatively. Examples are the dependence of the battery's capacity on temperature and discharge rate, as well as performance degradation upon recharge.Comment: 14 pages, 10 figure

A principled approach to the measurement of situation awareness in commercial aviation

The issue of how to support situation awareness among crews of modern commercial aircraft is becoming especially important with the introduction of automation in the form of sophisticated flight management computers and expert systems designed to assist the crew. In this paper, cognitive theories are discussed that have relevance for the definition and measurement of situation awareness. These theories suggest that comprehension of the flow of events is an active process that is limited by the modularity of attention and memory constraints, but can be enhanced by expert knowledge and strategies. Three implications of this perspective for assessing and improving situation awareness are considered: (1) Scenario variations are proposed that tax awareness by placing demands on attention; (2) Experimental tasks and probes are described for assessing the cognitive processes that underlie situation awareness; and (3) The use of computer-based human performance models to augment the measures of situation awareness derived from performance data is explored. Finally, two potential example applications of the proposed assessment techniques are described, one concerning spatial awareness using wide field of view displays and the other emphasizing fault management in aircraft systems

Speech Communication

Contains reports on three research projects.U. S. Air Force Cambridge Research Laboratories under Contract F19628-69-C-0044National Institutes of Health (Grant 5 RO1 NS04332-09)M.I.T. Lincoln Laboratory Purchase Order CC-57

Robust and reproducible model selection using bagged posteriors

Bayesian model selection is premised on the assumption that the data are generated from one of the postulated models, however, in many applications, all of these models are incorrect. When two or more models provide a nearly equally good t to the data, Bayesian model selection can be highly unstable, potentially leading to self-contradictory ndings. In this paper, we explore using bagging on the posterior distribution (\BayesBag") when performing model selection { that is, averaging the posterior model probabilities over many bootstrapped datasets. We provide theoreti- cal results characterizing the asymptotic behavior of the standard posterior and the BayesBag posterior under misspeci cation, in the model selection setting. We empir- ically assess the BayesBag approach on synthetic and real-world data in (i) feature selection for linear regression and (ii) phylogenetic tree reconstruction. Our theory and experiments show that in the presence of misspeci cation, BayesBag provides (a) greater reproducibility and (b) greater accuracy in selecting the correct model, compared to the standard Bayesian posterior; on the other hand, under correct speci- cation, BayesBag is slightly more conservative than the standard posterior. Overall, our results demonstrate that BayesBag provides an easy-to-use and widely applicable approach that improves upon standard Bayesian model selection by making it more stable and reproducible.First author draf

Robust inference and model criticism using bagged posteriors

Standard Bayesian inference is known to be sensitive to model misspecification, leading to unreliable uncertainty quantification and poor predictive performance. However, finding generally applicable and computationally feasible methods for robust Bayesian inference under misspecification has proven to be a difficult challenge. An intriguing, easy-to-use, and widely applicable approach is to use bagging on the Bayesian posterior (“Bayes- Bag”); that is, to use the average of posterior distributions conditioned on bootstrapped datasets. In this paper, we develop the asymptotic theory of BayesBag, propose a model–data mismatch index for model criticism using BayesBag, and empirically validate our theory and methodology on synthetic and real-world data in linear regression, sparse logistic regression, and a hierarchical mixed effects model. We find that in the presence of significant misspecification, BayesBag yields more reproducible inferences and has better predictive accuracy than the standard Bayesian posterior; on the other hand, when the model is correctly specified, BayesBag produces superior or equally good results. Overall, our results demonstrate that BayesBag combines the attractive modeling features of standard Bayesian inference with the distributional robustness properties of frequentist methods, providing benefits over both Bayes alone and the bootstrap alone.First author draf

Advanced stratified charge rotary aircraft engine design study

A technology base of new developments which offered potential benefits to a general aviation engine was compiled and ranked. Using design approaches selected from the ranked list, conceptual design studies were performed of an advanced and a highly advanced engine sized to provide 186/250 shaft Kw/HP under cruise conditions at 7620/25,000 m/ft altitude. These are turbocharged, direct-injected stratified charge engines intended for commercial introduction in the early 1990's. The engine descriptive data includes tables, curves, and drawings depicting configuration, performance, weights and sizes, heat rejection, ignition and fuel injection system descriptions, maintenance requirements, and scaling data for varying power. An engine-airframe integration study of the resulting engines in advanced airframes was performed on a comparative basis with current production type engines. The results show airplane performance, costs, noise & installation factors. The rotary-engined airplanes display substantial improvements over the baseline, including 30 to 35% lower fuel usage

The development of a program analysis environment for Ada

A unit level, Ada software module testing system, called Query Utility Environment for Software Testing of Ada (QUEST/Ada), is described. The project calls for the design and development of a prototype system. QUEST/Ada design began with a definition of the overall system structure and a description of component dependencies. The project team was divided into three groups to resolve the preliminary designs of the parser/scanner: the test data generator, and the test coverage analyzer. The Phase 1 report is a working document from which the system documentation will evolve. It provides history, a guide to report sections, a literature review, the definition of the system structure and high level interfaces, descriptions of the prototype scope, the three major components, and the plan for the remainder of the project. The appendices include specifications, statistics, two papers derived from the current research, a preliminary users' manual, and the proposal and work plan for Phase 2

Cross-Cultural Differences and Psychometric Properties of the Japanese Actions and Feelings Questionnaire (J-AFQ)

Aims: We aimed to assess the psychometric properties of a Japanese version of the Actions and Feelings Questionnaire (J-AFQ), an 18-item self-report measure of non-verbal emotional communication, as well as to examine its transcultural properties.Methods: The J-AFQ was administered to 500 Japanese adults (age 20–49, 250 male), alongside the Japanese Broad Autism Phenotype Questionnaire (BAPQ-J) and Empathy Quotient (EQ-J). These were compared to a group of 597 British and Irish participants (age 16–18, 148 male). J-AFQ was assessed in terms of validity by confirmatory factor analysis and convergence with BAPQ-J and EQ-J using Pearson correlation. Internal consistency and differential item functioning (DIF) were assessed and compared between Japanese and UK/Irish participants.Results: Reversed worded items (RWIs) showed poor item-total correlations but excluding these left a 13-item version of the J-AFQ with good internal consistency and content validity. Consistent with the English version, J-AFQ scores correlated with EQ and lower BAPQ scores. However, comparing across cultures, J-AFQ scores were significantly lower in the Japanese sample, and there was evidence of important DIF by country in over half of the J-AFQ itemsConclusion: Cultural differences in attitudes to self-report, as well as increased acquiescence to RWI's also seen in previous studies, limit the value of the 18-item instrument in Japanese culture. However, the 13-item J-AFQ is a valid and reliable measure of motor empathy, which, alongside the English version, offers promise for research in motor cognition and non-verbal emotional communication across cultures

Speech Communication

Contains research objectives and summary of research.National Institutes of Health (Grant 2 RO1 NS04332-11)National Institutes of Health (Grant 5 RO1 NS04332-11)U. S. Navy Office of Naval Research (Contract ONR N00014-67-A-0204-0069

Foreign Direct Investments in Business Services: Transforming the Visegrád Four Region into a Knowledge-based Economy?

Foreign direct investments (FDIs) in the service sector are widely attributed an important role in bringing more skill-intensive activities into the Visegrad Four (V4). This region—comprising Poland, the Czech Republic, Hungary and Slovakia—relied heavily on FDIs in manufacturing, which was often found to generate activities with limited skill content. This contribution deconstructs the chaotic concept of “business services” by analysing the actual nature of service sector activities outsourced and offshored to the V4. Using the knowledge-based economy (KBE) as a benchmark, the paper assesses the potential of service sector outsourcing in contributing to regional competitiveness by increasing the innovative capacity. It also discusses the role of state policies towards service sector FDI (SFDI). The analysis combines data obtained from case studies undertaken in service sector outsourcing projects in V4 countries. Moreover, it draws on interviews with senior employees of investment promotion agencies and publicly available data and statistics on activities within the service sector in the region. It argues that the recent inward investments in business services in the V4 mainly utilize existing local human capital resources, and their contribution to the development of the KBE is limited to employment creation and demand for skilled labour