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Child welfare agencies are increasingly required to leverage their limited resources to meet nearly limitless demands. As a result, agencies are searching for new opportunities to efficiently improve policy and practice, and advances in data availability and technology have brought increased attention to the utility of predictive modeling. While the literature has often highlighted the considerable potential of predictive models leveraging “big data”, discussions of the methodology and the associated best practices remain critically absent. To address this gap, this paper provides an illustrative case involving the development and testing of models used to predict the probability of whether U.S. foster children would achieve legal permanency. The models were trained and tested using a national administrative dataset of 233,633 foster care children that discharged from state child welfare systems in 2013. The optimal model, a boosted tree, predicted whether children would achieve permanency with 97.66% accuracy. The paper concludes with a discussion of best practices detailing how agencies can utilize predictive modeling to enhance policy and practice. [ABSTRACT FROM AUTHOR]

Researchers and foreign language (FL) educators alike have investigated changes in learners' intercultural competence (IC) in response to pedagogical interventions aimed at preparing learners for cross-cultural encounters. Byram's (1997) multimodal IC model and Bennett's (1993) developmental model of intercultural sensitivity (DMIS) are predominant IC assessment models in the field of FL education. This paper reports empirical evidence that reveals discrepancies between these two models drawing from the findings of a larger study that employed both theoretical lenses to investigate culture learning in a computer-mediated environment. Specifically, the study investigated changes in the way 13 U.S. French language learners talked about French people and culture in online classroom discussions in response to virtual instruction about French cultural practices at two levels: (1) at the individual level--with Byram's IC model in three case studies and (2) at the group level--with Bennett's DMIS. A post hoc comparison of the findings revealed assessment discrepancies between the models--empirical evidence revealing contradictions both between and within the models. These discrepancies are reported and the merits of each model within the research design are discussed. The aim of this paper is to empower readers with an understanding of IC research instruments and assessment tools commonly used to measure IC development in FL education and to inform methodological decisions of future research. [ABSTRACT FROM AUTHOR]

In this paper, we present novel evidence of the extent to which intergenerational mobility is generalized or specific across domains of human and health capital. That is, do children who experience greater mobility in one domain (e.g., income) also experience mobility in other domains (education, health status, health behaviors, crime). Using rich data in Add Health, we find evidence against generalized mobility—families that are more mobile in one domain are not more mobile in others. We then ask a place-based version of this question, motivated by Chetty et al. (2014)'s work showing high levels of geographically-based income mobility in the US. The school-based sampling combined with parent-child links across many outcome domains of the Add Health allows us to use a common dataset between the two analyses. Like our individual-based results, we find limited evidence of generalized mobility by place—indeed, most estimates suggest close-to-zero correlations between many of the ten domains we explore. • Theoretically, intergenerational mobility could be generalized or specific. • Empirically, we find more evidence of specific mobility. • People and places with high income mobility may not have high health mobility. [ABSTRACT FROM AUTHOR]

Empirical evidence points to a persistent Black-White racial gap in police-caused homicides. Some scholarship treats the gap as denoting criminal justice exposure either in terms of involvement in crime or living in a high-crime context. By contrast, health scholarship typically points to the importance of racism including the attitudes, institutional practices, and overall structures that operate to privilege one group over another. Still, given the demographics of US society, the Black-White racial contrast overlooks the 25% of Americans who are neither Black nor White: Native Americans, Latinos, and Asians. The question of how the groups should be organized vis-a-vis the current Black-White model and theories arises. An answer is not straightforward. There is a rank-ordering to the groups' mortality rates as well as an exponential increase in the number of possible comparisons. In this paper we systematically review the literature on race and police-caused homicide with a particular focus on studies that attempt to move beyond the Black-White model. We find that studies on race and police-caused homicide either make no comparison between the groups, or, alternatively, use a White-non-White, a Black-non-Black, and/or a Black-Native American-Latino vs. White-Asian comparison. We use data on group-specific mortality rates to examine the strengths and limits of each of these practices. The limits are the selection of counterfactual gaps, the selection of smaller gaps, and/or the omission of larger gaps. To address these limits, we propose that a Black-Native American vs. Latino-White-Asian model best captures the higher and lower mortality rates in police-caused homicide data. • Mortality rates from police-caused homicide vary by race and ethnicity. • The Black group has the highest rate followed by the Native American, Latino, White and Asian groups. • The literature makes one of several contrasts between these groups. • These are White-non-White; Black-non-Black, or Black-Native American-Latino vs. White-Asian. • Black-Native American vs. Latino-White-Asian contrast best reflects the groups' mortality rates. [ABSTRACT FROM AUTHOR]

Many studies have examined the diffusion of health care innovation but less is known about the diffusion of health care fraud. In this paper, we consider the diffusion of potentially fraudulent Medicare home health care billing in the United States during 2002–16, with a focus on the 21 hospital referral regions (HRRs) covered by local Department of Justice (DOJ) anti-fraud "strike force" offices. We hypothesize that patient-sharing across home health care agencies (HHAs) provides a mechanism for the rapid diffusion of fraudulent strategies. We measure such activity using a novel bipartite mixture (or BMIX) network index, which captures patient sharing across multiple agencies and thus conveys more information about the diffusion process than conventional unipartite network measures. Using a complete population of fee-for-service Medicare claims data, we first find a remarkable increase in home health care activity between 2002 and 2009 in many regions targeted by the DOJ; average billing per Medicare enrollee in McAllen TX and Miami increased by $2127 and $2422 compared to just an average $289 increase in other HRRs not targeted by the DOJ. Second, we establish that the HRR-level BMIX (but not other network measures) was a strong predictor of above-average home health care expenditures across HRRs. Third, within HRRs, agencies sharing more patients with other agencies were predicted to increase billing. Finally, the initial 2002 BMIX index was a strong predictor of subsequent changes in HRR-level home health billing during 2002–9. These results highlight the importance of bipartite network structure in diffusion and in infection and contagion models more generally. • In some regions, Medicare home health care billing rose > 3-fold over 2002–2009. • A theoretical model linking home health agencies billing to their regional network. • Novel bipartite measure for the regional network of home health agencies. • The bipartite network measure strongly predicts regional home health billing. • There is evidence of peer-associations in agencies billing and treatment practices. [ABSTRACT FROM AUTHOR]

Abstract: Weak roof conditions in underground coal mines are a common occurrence and cause significant problems in delaying production. This work presents innovative way of using directional drilling method for roof support in weak sandstone conditions other than conventional method such as bolting, trussing, and cribbing methods. This paper presents a conceptual model of pipe umbrella roof support methods intended for employment in the underground coal mining environment over a single entry of a development section. The design methodology was evaluated by examining a case study of a western U.S. coal mine, and its specific geologic conditions. This work used extensive literature reviews and laboratory test results of the mine. Geotechnical laboratory testing was performed for a weak sandstone channel material that occurs in large extents at the mine for input into numerical models. 2D and 3D models in FLAC were developed. These models utilize beam elements embedded in the continuum model. Results from the modeling showed that bending moments vary in the embedded beams based on the pipe spacing and the diameter of the pipes. A design criterion for a pipe umbrella system was based on the developed bending moment due to undermining and the commonly used flexure formula for bending stress. A safety factor approach was used in this paper for the design of a pipe umbrella system. [Copyright &y& Elsevier]

Abstract: This paper analyzes the impact of voucher design on student sorting in the application and enrollment phases of parental choice. Much of the existing literature investigates the question of sorting where private schools can screen students. However, the publicly funded U.S. voucher programs require private schools to accept all students unless oversubscribed and to pick students randomly if oversubscribed. In the context of a theoretical model, this paper argues that this feature coupled with the absence of topping up of vouchers can preclude sorting by income in the application stage, although there is still sorting by ability. This design can avert sorting by ability in the enrollment stage, but revelation of new monetary costs can lead to sorting by income. Using a logit model and student level data from the Milwaukee voucher program for 1990–1994, this study finds robust evidence that this indeed has been the case in reality. [Copyright &y& Elsevier]

Abstract: M. King Hubbert’s 1956 prediction of a ‘peak’ in US oil production has spurred a durable and divisive debate on the exhaustion of the petroleum resource. Pitting physical against economic explanations of resource scarcity, the peak oil debate has seemingly sunk into the well-worn grooves of a long history of scarcity debates. Yet, as this paper argues, this ‘stale dichotomy’ can partly be attributed to a severance from the contexts and ideas that informed Hubbert’s mathematical calculations. Specifically, this paper examines the broader influences on the peak oil model: Hubbert’s career in the newly formed field of geophysics; his personal concern with the relationship between energy and population growth; and his ties to Technocracy, Inc., a social movement originating in the US that aimed to replace political and business control with a group of specialist engineers and technicians. The paper further emphasizes the importance of institutional and political interests to the arguments launched against Hubbert, and in motivating change in this opposition over time. Last, it makes the case that the contemporary de-contextualization of Hubbert’s model has contributed towards a narrow focus of discussions within the oil industry and in certain governments on predicting the timing of a global peak, without addressing the wider questions implied by Hubbert’s model. [Copyright &y& Elsevier]

Abstract: Land use change modeling and simulation is a popular tool in land use planning and policy formulation. However, the outputs of land use change simulation are not always accompanied with information on uncertainty. The goal of this paper is to demonstrate the inherent uncertainty in sprawl simulation, which is attributable to error in the input parameters and to limitations in our understanding of land use systems. To reach this goal, the paper determines sprawl simulation accuracy and uncertainty for a small US metropolitan region as produced by the CLUE-S modeling framework. The model simulates sprawl location in the region accurately, but the certainty of sprawl location projections decreases with time. This uncertainty in the simulation suggests that modelers should report uncertainty with their output over all time horizons so that, on the one hand, land use planners and decision makers do not place too much confidence in any single sprawl simulation (which could lead to unwarranted and expensive urban growth management policies) and, on the other hand, do not place too little confidence in sprawl models (which could have severe socioeconomic and environmental consequences). Thus, reporting uncertainty with simulation output provides planners and decision makers with a platform for more informed land use policy. [Copyright &y& Elsevier]

A field measurement and computer modeling effort was made to assess the dilution field of pulped waste materials discharged into the wake of a US Navy frigate. Pulped paper and fluorescein dye were discharged from the frigate’s pulper at known rates. The subsequent particle and dye concentration field was then measured throughout the wake by a following vessel using multiple independent measures. Minimum dilution of the pulped paper reached 3.2 × 105 within 1900 m behind the frigate, or about 8 min after discharge. Independent measures typically agreed within 25% of one another and within 20% of model predictions. Minimum dilution of dye reached 2.3 × 105 at a down-wake distance of approximately 3500 m, or roughly 15 min. Comparison to model measurements were again within 20%. The field test was not only successful at characterizing wake dilution under one set of at-sea conditions, but was successful at validating the computer model used for assessing a wide range of ships and conditions. [Copyright &y& Elsevier]

Abstract: Water-quality standards requiring simultaneous low level effluent N and P concentrations are increasingly common in Europe and the United States of America. Moving bed biofilm reactors (MBBRs) and biologically active filters (BAFs) have been used as post-denitrification biofilm reactors in processes designed and operated for this purpose (Boltz et al., 2010a). There is a paucity of information describing systematic design and operational protocols that will minimize the potential for phosphorus rate-limited conditions as well as a lack of information describing the interaction between these post-denitrification biofilm reactors and unit processes that substantially alter phosphorus speciation (e.g., chemically enhanced clarification). In this paper, a simple mathematical model for estimating the threshold below which P becomes rate-limiting, and the model is presented and evaluated by comparing its predictions with operational data from post-denitrification MBBRs and BAFs. Ortho-phosphorus (PO4–P), which is the dissolved reactive component of total phosphorus, was a primary indicator of P rate-limiting conditions in the evaluated post-denitrification biofilm reactors. The threshold below which PO4–P becomes the rate-limiting substrate is defined:  = 0.0086 g P/g N and  = 0.0013 g P/g COD. Additional analyses indicate when  > 0.0086, and when  < 0.0086. Effluent nitrate–nitrogen plus nitrite–nitrogen concentration from the evaluated post-denitrification biofilm reactors began to rapidly increase when was 0.01, approximately (consistent with the rate-limitation threshold of  < 0.0086 predicted by the mathematical model described in this paper). Depending on the processes used at a given WWTP, optimizing chemically enhanced clarification to increase the amount of PO4–P that remains in the clarifiers effluent stream, dosing phosphoric acid in the MBBR or BAF influent stream, and/or optimizing secondary process EBPR may overcome phosphorus rate-limitations in the biofilm-based post-denitrification process. [Copyright &y& Elsevier]

Abstract: This paper considers the maximum likelihood estimation of a class of structural vector autoregressive fractionally integrated moving-average (VARFIMA) models. The structural VARFIMA model includes the fractional cointegration model as one of its special cases. We show that the conditional likelihood Durbin–Levinson (CLDL) algorithm of Tsay (2010a) is a fast and reliable approach to estimate the long-run effects as well as the short- and long-term dynamics of a structural VARFIMA process simultaneously. In particular, the computational cost of the CLDL algorithm is much lower than that proposed in Sowell (1989) and Dueker and Startz (1998). We apply the CLDL method to the Congressional approval data of Durr et al. (1997) and find that the long-run effect of economic expectations on Congressional approval is at least 0.5718, which is over twice the estimate of 0.24 found in Table 2 of Box-Steffensmeier and Tomlinson (2000). This paper also tests the divided party government hypothesis with the CLDL algorithm. [Copyright &y& Elsevier]

Abstract: This paper focuses on the assessment of pressure suppression pool hydrodynamics in the advanced boiling water reactor (ABWR) containment under design-basis, loss-of-coolant accident (LOCA) conditions. The paper presents a mechanistic model for predicting various suppression pool hydrodynamics parameters. A phenomena identification and ranking table (PIRT) applicable to the ABWR containment pool hydrodynamics analysis is used as a basis for the development of the model. The highly ranked phenomena are represented by analytic equations or empirical correlations. The best estimate and several sensitivity calculations are performed for the ABWR containment using this model. Results of the sensitivity calculations are also presented that demonstrate the influence of key model parameters and assumptions on the pool hydrodynamics parameters. A comparison of model predictions to the results of the licensing analyses shows reasonable agreement. Comparison of the results of the proposed model to experimental data shows that the model predicted top vent clearance time, the pool swell height, and the bubble breakthrough elevation are within 10% of the data. The predicted pool surface velocity and the liquid slug thickness are within 30% of the measurements, which is considered adequate given the large uncertainties in the experimental measurements. [Copyright &y& Elsevier]

Abstract: This paper presents an optimal control strategy suitable for investigating the mission performance of a spacecraft equipped with a NASAʼs Evolutionary Xenon Thruster. Using an accurate mathematical model of the propulsion system, based on both experimental data and a semi-empirical schematization of the power generation system, the minimum-time rendezvous problem with various celestial bodies is investigated through an indirect approach. Unlike a conventional approach, in which the thruster power is varied with continuity within a given range, here the solar electric propulsion system is described using a finite number of operation points, characterized by different pairs of thruster input power and propellant mass flow rate. The model includes the possibility of obtaining coasting phases along the spacecraft trajectory. The optimal control strategy is found for a three-dimensional problem in which the actual shape and relative orientation of the initial and final orbits are taken into account. The paper presents the simulation results for a number of minimum-time trajectories towards inner planets (Mercury, Venus, and Mars) and three Near Earth Asteroids (NEAs) of particular interest for the scientific community: 1998 KY-26, 99942 Apophis, and 2007 VK-184. [Copyright &y& Elsevier]

Abstract: Electricity systems models are software tools used to manage electricity demand and the electricity systems, to trade electricity and for generation expansion planning purposes. Various portfolios and scenarios are modelled in order to compare the effects of decision making in policy and on business development plans in electricity systems so as to best advise governments and industry on the least cost economic and environmental approach to electricity supply, while maintaining a secure supply of sufficient quality electricity. The modelling techniques developed to study vertically integrated state monopolies are now applied in liberalised markets where the issues and constraints are more complex. This paper reviews the changing role of electricity systems modelling in a strategic manner, focussing on the modelling response to key developments, the move away from monopoly towards liberalised market regimes and the increasing complexity brought about by policy targets for renewable energy and emissions. The paper provides an overview of electricity systems modelling techniques, discusses a number of key proprietary electricity systems models used in the USA and Europe and provides an information resource to the electricity analyst not currently readily available in the literature on the choice of model to investigate different aspects of the electricity system. [ABSTRACT FROM AUTHOR]

Abstract: This paper examines the relationship between contemporary racial inequality of schooling and the black–white wage gap in the U.S. In particular I ask: what policies would be effective at reducing the black–white wage gap in the U.S.? In order to address this question, I develop a model of human capital accumulation in which agents differ by race. I calibrate the model to reflect the U.S. system of education financing since the mid-1950s, and find that more than half of the black–white wage gap in the U.S. in the early 1990s can be accounted for by differential human capital accumulation by race. This indicates an increased role for policy in addressing racial inequality in the U.S. The results of the policy experiments conducted in this paper indicate that a conditional cash transfer program and a policy of decreased reliance on local property tax revenue would be effective in reducing the black–white skill and wage gaps. [Copyright &y& Elsevier]

Abstract: High rates of oil consumption and obesity in the US have become important socioeconomic concerns. While these concerns may seem unrelated at first, growing obesity rates in the US increase fuel consumption by adding passenger weight to vehicles. This paper estimates the additional amount of fuel (i.e., gasoline) consumed annually by noncommercial passenger highway vehicles in the US due to passenger overweight and obesity. The mathematical model presented in this paper estimates that as many as one billion additional gallons of gasoline are consumed each year due to overweight and obesity in the US, accounting for up to 0.8% of the fuel consumed by these vehicles annually. This additional fuel consumption causes carbon dioxide emissions of up to 20 billion pounds or more, accounting for up to 0.5% of the annual carbon dioxide emissions in the transportation sector. [Copyright &y& Elsevier]

Abstract: Up to now, of all the containers received in USA ports, roughly between 2% and 5% are scrutinized to determine if they could cause some type of danger or contain suspicious goods. Recently, concerns have been raised regarding the type of attack that could happen via container cargo leading to devastating economic, psychological and sociological effects. Overall, this paper is concerned with developing an inspection strategy that minimizes the total cost of inspection while maintaining a user-specified detection rate for “suspicious” containers. In this respect, a general model for describing an inspection strategy is proposed. The strategy is regarded as an (n+1)-echelon decision tree where at each of these echelons, a decision has to be taken, regarding which sensor to be used, if at all. Second, based on the general decision-tree model, this paper presents a minimum cost container inspection strategy that conforms to a pre-specified user detection rate under the assumption that different sensors with different reliability and cost characteristics can be used. To generate an optimal inspection strategy, an evolutionary optimization approach known as probabilistic solution discovery algorithm has been used. [Copyright &y& Elsevier]

Abstract: This paper presents an overview of QRAS, the Quantitative Risk Assessment System. QRAS is a PC-based software tool for conducting Probabilistic Risk Assessments (PRAs), which was developed to address risk analysis needs held by NASA. QRAS is, however, applicable in a wide range of industries. The philosophy behind the development of QRAS is to bridge communication and skill gaps between managers, engineers, and risk analysts by using representations of the risk model and analysis results that are easy to comprehend by each of those groups. For that purpose, event sequence diagrams (ESD) are being used as a replacement for event trees (ET) to model scenarios, and the quantification of events is possible through a set of quantification models familiar to engineers. An automated common cause failure (CCF) modeling tool further aids the risk modeling. QRAS applies BDD-based algorithms for the accurate and efficient computation of risk results. The paper presents QRAS'' modeling and analysis capabilities. The performance of the underlying BDD algorithm is assessed and compared to that of another PRA software tool, using a case study extracted from the International Space Station PRA. [Copyright &y& Elsevier]

Abstract: The increasing diversity of vehicle type holdings and the growing usage of vehicles by households have serious policy implications for traffic congestion and air pollution. Consequently, it is important to accurately predict the vehicle holdings of households as well as the vehicle miles of travel by vehicle type to project future traffic congestion and mobile source emission levels. In this paper, we apply a multiple discrete-continuous extreme value model to analyze the holdings and use of multiple vehicle types by households. Data for the analysis is drawn from a 2000 San Francisco Bay Area survey. The model results indicate the important effects of household demographics, residence location variables and vehicle attributes on vehicle type holdings and use. The model developed in the paper can be applied to predict the impact of demographic, land use, and operating cost changes on vehicle type holdings and usage. Such predictions are important at a time when the household demographic characteristics are changing rapidly in the United States. The predictions can also inform the design of proactive land-use, economic, and transportation policies to influence household vehicle holdings and usage in a way that reduces traffic congestion and air quality problems. [Copyright &y& Elsevier]

The ‘wildland–urban interface’ (WUI) is a term commonly used to describe areas where wildfires and the built environment have the potential to interact resulting in loss of properties and potential loss of life. Significant residential losses associated with wildland interface fires have occurred worldwide in recent years and substantial research has been conducted on developing numerical models of ignition due to convection and ember attacks. These studies provide substantial insight into the behaviour and growth of wildland fires, which have been further utilized to build fire exposure rating of structures. The FireWise program in the United States and the FireSmart manual in Canada are two key examples of provisions developed for determining fire exposure ratings for a structure. While previous studies provide significant contribution to modelling fire propagation, a much more comprehensive model is required, which would encompass all the key variables associated with WUI fires. This paper aims at extending previously conducted efforts by developing a simulation-based model. A typical fire propagation simulation requires solving the coupled fluid-thermal differential equations which results in extreme run times making it unsuitable for general purposes, however the model in this study utilizes theory of cellular automata, which reduces the processing times substantially by simplifying the underlying equations involved. Cellular automata utilize a specific set of rules to model propagation by convection as well as ember travel. In addition, the model also considers key parameters such as humidity, nature of vegetation and topology while evaluating the propagation paths. Due to the flexible nature of the model its accuracy can be tuned to a certain extent by optimizing the propagation rules using real-event data [ABSTRACT FROM AUTHOR]

Dyslipidemia is a common pathology throughout the industrialized world, and HMG-CoA reductase inhibitors (statins) are often administered to treat elevated lipid levels. Substantial concern has been raised regarding the aggressive clinical lowering of cholesterol, particularly in light of a growing body of research linking low circulating lipid levels with negative behavioral outcomes in both human samples and non-human primate models. In 2009, Goldstein and colleagues tentatively speculated that the greed, impulsiveness, and lack of foresight that lead to the worldwide economic collapse in 2007-2008 could have been caused (in part) by depressed population cholesterol levels resulting from the widespread use of statins by workers in the financial services industry. This paper reviews the literature that links low circulating lipid levels with neurobehavioral dysfunction, develops Goldstein and colleagues' initial speculation into a formal hypothesis, and proposes several specific studies that could rigorously empirically evaluate this hypothesis. [ABSTRACT FROM AUTHOR]

Serious child illness and hospitalization can have a lasting negative impact on children and their families. Pediatric psychosocial care (PPC) approaches are implemented to promote child resilience within medical settings and to optimize quality of life for children affected by chronic health conditions. However, numerous opportunities remain to adopt best practices and enhance the well-being of children facing illness and hospitalization in the United States and globally. This paper situates contemporary approaches to PPC within their historical context, beginning in the early 20th century. Prominent theories that guide PPC professionals' work with hospitalized children and their families are reviewed, highlighting the practical implications of these theories for family systems-oriented practitioners working with hospitalized children. An approach to integrating theory with practice for the eclectic practitioner is illustrated using a hypothetical case study. Finally, the paper concludes with recommendations for building the evidence base for PPC through theory-driven research and quality improvement initiatives. [ABSTRACT FROM AUTHOR]

Energy system optimization models (ESOMs) should be used in an interactive way to uncover knife-edge solutions, explore alternative system configurations, and suggest different ways to achieve policy objectives under conditions of deep uncertainty. In this paper, we do so by employing an existing optimization technique called modeling to generate alternatives (MGA), which involves a change in the model structure in order to systematically explore the near-optimal decision space. The MGA capability is incorporated into Tools for Energy Model Optimization and Analysis (Temoa), an open source framework that also includes a technology rich, bottom up ESOM. In this analysis, Temoa is used to explore alternative energy futures in a simplified single region energy system that represents the U.S. electric sector and a portion of the light duty transport sector. Given the dataset limitations, we place greater emphasis on the methodological approach rather than specific results. [ABSTRACT FROM AUTHOR]

Maintenance free operating period (MFOP) philosophy is proposed by the UKMilitary Aerospace industry, which has advantages for both the operation andmaintenance of aircraft. An MFOP is a period of time for which the aircraft will operate without failureandwithout the need for anymaintenance, however, faults and minorplanned, contractually agreed maintenance are permissible.Each MFOP isfollowed by a MaintenanceRecovery Period (MRP) during which maintenance is performed on the aircraft tocorrect any failures which have occurred, carry out servicing and prepare the aircraft forthe next period of operation. There are several advantages to operating aircraft in thismanner. The first is that it will be known, with a high degree of confidence, howmany products will be available for operational purposes at any time. This enablesaccurate, effective mission planning. However, the aircraft must be designed tooperate in this way and be able to carry faults in the MFOP withoutan unacceptable risk. This paper will model the performance of aircraft utilizing maintenance freeoperating periods and explore issues relating to the design and operation of aircraft inthis manner. An example is provided to expatiate on the proposed approach. [ABSTRACT FROM AUTHOR]

Abstract: The Community Earth System Model (CESM) is one of US''s leading earth system modeling frameworks, which has decades of development history and was embraced by a large, active user community. In this paper, we first review the software development history of CESM and we explain the general objectives of performance analysis. Then we present an offline global community land model simulation within the CESM framework to demonstrate the procedure of runtime tracing of CESM using the Vampir toolset. Finally, we explain the benefits of runtime tracing to the general earth system modeling community. We hope those considerations can be beneficial to many other modeling research programs involving legacy high-performance computing applications. [Copyright &y& Elsevier]

Researchers have analyzed whether US welfare reform has induced interstate migration. Empirical results are inconclusive because methodologies are based on pre-reform thinking. This paper presents a post-reform migration model. We find that recipients move to avoid harsh sanction policies, seek lenient work requirements, and extend time limits. Unlike the first two behavioral responses, the latter is controversial. Critics will argue that such moves are illegal, and violators can be prosecuted because states share data. However, only active cases are being shared, meaning violators cannot be caught. Our model produces testable hypotheses which are consistent with (and reconcile) previous empirical results. [ABSTRACT FROM AUTHOR]

Abstract: With the impacts of climate change and impending crisis of potable water, potential sustainable sources of water are under investigations. One of such potential sources is fog water collection. In the past, collection of fog water was considered negligible and non-worthy. However, recent studies suggest that fog-water collection can be a reasonable sustainable source of water depending on favorable topographic and atmospheric conditions. This paper presents development of a mathematical model for fog-formation and eventual quantification of fog-water collection. The National Oceanic and Atmospheric Administration (NOAA) equation for dew point calculation has been modified and extended to incorporate effects of different climatic parameters on fog formation. A new parameter named Fog Potential Index (FPI), which is a function of difference between dew point and air temperature for a particular location has been introduced and defined. NOAA proposed an equation to calculate dew point based on actual water vapor pressure in the air, which can be calculated from dry bulb temperature of the air and relative humidity. Following calculation of average dew point using NOAA equation between a timestep, FPI was calculated for a particular time step. FPI for each timestep was multiplied with the humidity factor, wind velocity factor and area of the fog collector to incorporate the effects of humidity ratio, wind velocity and fog collector area in the quantification of fog water. Effect of wind velocity on fog formation has been discussed. It was found that wind velocity has got two-fold impacts on the formation of fog; (i) for a lower wind velocity upto a certain threshold value, fog formation increases with velocity as old condensed moist air is continuously replaced by new moist air, and (ii) for a higher wind velocity (beyond the threshold value), fog formation decreases with velocity due to disturbance in the formation of fog. The developed model was calibrated using fog-water collection experimental data from Asir region of Saudi Arabia. [Copyright &y& Elsevier]

Abstract: Responding to extant power imbalances in the typical redevelopment process, grounded theory is introduced to aid in recalibrating development suitability models to serve the interests of underrepresented communities resisting development. Using a community-based research model, this paper reports on testing the potential of grounded theory in a low-income, primarily Latino neighborhood of Chelsea, Massachusetts (USA). After 13 iterations and a ground-truthing exercise, the research resulted in a development suitability model that offers a useful heuristic for community leaders to view development likelihood – an innovation over the conventional development suitability model by directly incorporating community issues in the model calibration. [Copyright &y& Elsevier]

Abstract: There has been growing concern about the recent emergence of the critical challenges of energy availability and the impacts of climate change. Both are inextricably linked and dealing with them is fundamental to the progress of America and humanity. There are, however, a number of different views expressed, reflecting different assumptions, special interests, and partisan objectives. Decision-makers and the public need easy-to-use and transparent tools to better visualize, analyze, and understand the broader and longer-term implications of the varying underlying assumptions, policies, and strategies, including both their positive and negative impacts — both direct and indirect — and how to manage them. Threshold 21 (T21) the simulation model presented in this paper aims to become such a tool. The Millennium Institute has developed it over the last 24years. The T21-USA model results indicate that a continuation of current policies and trends will lead the US to become increasingly dependent on foreign energy resources and more vulnerable to price fluctuations. Furthermore, alternative scenarios simulating improved CAFE and Renewable Portfolio Standards (RPS) show that major reductions in the US'' resource consumption and pollution generation could be possible while stimulating the economy over the medium and longer term. Nevertheless, the model shows that unintended consequences, such as the Jevons Paradox, have to be taken into consideration when defining national energy policies. [Copyright &y& Elsevier]

Abstract: The availability of realistic benchmark configurations is essential to enable the validation of current Computational Aeroacoustic (CAA) methodologies and to further the development of new ideas and concepts that will foster the technologies of the next generation of CAA tools. The selection of a real-world configuration, the subsequent design and fabrication of an appropriate model for testing, and the acquisition of the necessarily comprehensive aeroacoustic data base are critical steps that demand great care and attention. In this paper, a brief account of the nose landing-gear configuration, being proposed jointly by NASA and the Gulfstream Aerospace Company as an airframe noise benchmark, is provided. The underlying thought processes and the resulting building block steps that were taken during the development of this benchmark case are given. Resolution of critical, yet conflicting issues is discussed – the desire to maintain geometric fidelity versus model modifications required to accommodate instrumentation; balancing model scale size versus Reynolds number effects; and time, cost, and facility availability versus important parameters like surface finish and installation effects. The decisions taken during the experimental phase of a study can significantly affect the ability of a CAA calculation to reproduce the prevalent flow conditions and associated measurements. For the nose landing gear, the most critical of such issues are highlighted and the compromises made to resolve them are discussed. The results of these compromises will be summarized by examining the positive attributes and shortcomings of this particular benchmark case. [Copyright &y& Elsevier]

Abstract: There is considerable research interest on the meaning and measurement of resilience from a variety of research perspectives including those from the hazards/disasters and global change communities. The identification of standards and metrics for measuring disaster resilience is one of the challenges faced by local, state, and federal agencies, especially in the United States. This paper provides a new framework, the disaster resilience of place (DROP) model, designed to improve comparative assessments of disaster resilience at the local or community level. A candidate set of variables for implementing the model are also presented as a first step towards its implementation. [Copyright &y& Elsevier]

Abstract: Breakup model is the key area of space debris environment modeling. NASA standard breakup model is currently the most widely used for general-purpose. It is a statistical model found based on space surveillance data and a few ground-based test data. NASA model takes the mass, impact velocity magnitude for input and provides the fragment size, area-to-mass ratio, velocity magnitude distributions for output. A more precise approach for spacecraft disintegration fragment analysis is presented in this paper. This approach is based on hypervelocity impact dynamics and takes the shape, material, internal structure and impact location etc. of spacecraft and impactor, which might greatly affect the fragment distribution, into consideration. The approach is a combination of finite element and particle methods, entitled finite element reconstruction (FER). By reconstructing elements from the particle debris cloud, reliable individual fragments are identified. Fragment distribution is generated with undirected graph conversion and connected component analysis. Ground-based test from literature is introduced for verification. In the simulation satellite targets and impactors are modeled in detail including the shape, material, internal structure and so on. FER output includes the total number of fragments and the mass, size and velocity vector of each fragment. The reported fragment distribution of FER shows good agreement with the test, and has good accuracy for small fragments. [Copyright &y& Elsevier]

Abstract: This paper examines the impact of cell phone usage on truck accident rates in the United States using econometric models and specification error tests. The models focus on the potential nonlinear effect of cell phones on these accidents. The results indicate that increases in cell phone usage increase truck accident rates, but at a declining rate. [Copyright &y& Elsevier]

Abstract: Waves and currents create bottom shear stress, a force at the seabed that influences sediment texture distribution, micro-topography, habitat, and anthropogenic use. This paper presents a methodology for assessing the magnitude, variability, and driving mechanisms of bottom stress and resultant sediment mobility on regional scales using numerical model output. The analysis was applied to the Middle Atlantic Bight (MAB), off the U.S. East Coast, and identified a tidally-dominated shallow region with relatively high stress southeast of Massachusetts over Nantucket Shoals, where sediment mobility thresholds are exceeded over 50% of the time; a coastal band extending offshore to about 30m water depth dominated by waves, where mobility occurs more than 20% of the time; and a quiescent low stress region southeast of Long Island, approximately coincident with an area of fine-grained sediments called the “Mud Patch”. The regional high in stress and mobility over Nantucket Shoals supports the hypothesis that fine grain sediment winnowed away in this region maintains the Mud Patch to the southwest. The analysis identified waves as the driving mechanism for stress throughout most of the MAB, excluding Nantucket Shoals and sheltered coastal bays where tides dominate; however, the relative dominance of low-frequency events varied regionally, and increased southward toward Cape Hatteras. The correlation between wave stress and local wind stress was lowest in the central MAB, indicating a relatively high contribution of swell to bottom stress in this area, rather than locally generated waves. Accurate prediction of the wave energy spectrum was critical to produce good estimates of bottom shear stress, which was sensitive to energy in the long period waves. [Copyright &y& Elsevier]

Abstract: In this paper, we propose a comprehensive three-stage multiple criteria decision making framework for portfolio selection based upon financial and ethical criteria simultaneously. It may be noted that the ethical investment movement that began from the USA in 1960s has gained tremendous momentum the world over recently. The growing instances of corporate scams and scandals have made it incumbent upon the investors to consider the quality of governance of corporations and ethicality of their conduct. Indeed, there has been a spate of reforms relating to corporate laws and capital markets all over the world. Also, the investors are becoming conscious of the desirability of ethical evaluation of the assets. The growing influence of institutional investors has reinforced this consciousness. Hence, the research in the area must take cognizance of these developments to construct models that accord due consideration to ethical criteria besides the financial criteria. We use multiple methodologies toward the purpose. Analytical hierarchy process technique is used to obtain the ethical performance score of each asset based upon investor-preferences. A fuzzy multiple criteria decision making method is used to obtain the financial quality score of each asset based upon investor-ratings on the financial criteria. Three hybrid portfolio optimization models are developed to obtain well diversified financially and ethically viable portfolios. These models have maximization of financial goal as main objective and differ in the way the ethical goal is pursued by the investor. Numerical illustrations are included to demonstrate the suitability of the models for obtaining diversified portfolios that meet the investor’s financial and ethical goals. [Copyright &y& Elsevier]

Abstract: Patent users such as governments, inventors, and manufacturing organizations strive to identify the directions in which new technology is advancing, and their goal is to outline the boundaries of existing knowledge. The paper analyzes patent knowledge to identify research trends. A model based on knowledge extraction from patents and self-organizing maps for knowledge representation is presented. The model was tested on patents from the United States Patent and Trademark Office. The experiments show that the method provides both an overview of the directions of the trends and a drill-down perspective of current trends. [Copyright &y& Elsevier]

Abstract: Many governmental space activities need to be planned with a time horizon that extends beyond the comfort zone of reliable technology development assessments and predictions. In an environment of accelerating technological change, a methodological approach to addressing non-core technology trends and potentially disruptive, game-changing developments not yet linked to the space sector is increasingly important to complement efforts in core technology R&D planning. Various models and organisational setups aimed at fulfilling this purpose are in existence. These include, with varying levels of relevance to space, the National Aeronautics and Space Administration (NASA) Institute for Advanced Concepts (NIAC, operational form 1998 to 2007 and recently re-established), the Defence Advanced Research Projects Agency of the US Department of Defence, the Massachusetts Institute of Technology (MIT) Medialab, the early versions of Starlab, the Lockheed Skunk Works and the European Space Agency''s Advanced Concepts Team. Some of these organisations have been reviewed and assessed individually, though systematic comparison of their methods, approaches and results have not been published. This may be due in part to the relatively sparse scientific literature on organisational parameters for enabling disruptive innovation as well as to the lack of commonly agreed indicators for the evaluation of their performance. Furthermore, innovation support systems in the space sector are organised differently than in traditional, open competitive markets, which serve as the basis for most scholarly literature on the organisation of innovation. The present paper is intended to advance and stimulate discussion on the organisation of disruptive innovation mechanisms specifically for the space sector. It uses the examples of the NASA Institute for Advanced Concepts and the ESA Advanced Concepts Team, analyses their respective approaches and compares their results, leading to the proposal of measures for the analysis and eventual evaluation of research for disruptive innovation in the space sector. [Copyright &y& Elsevier]

Abstract: The objective of this paper was to determine if three different direct normal irradiance (DNI) models were sufficiently accurate to determine if concentrating solar power (CSP) plants could meet the utility electrical load. DNI data were measured at three different laboratories in the United States and compared with DNI calculated by three DNI models. In addition, utility electrical loading data were obtained for all three locations. The DNI models evaluated were: the Direct Insolation Simulation Code (DISC), DIRINT, and DIRINDEX. On an annual solar insolation (e.g. kWh/m2) basis, the accuracy of the DNI models at all three locations was within: 7% (DISC), 5% (DIRINT), and 3% (DIRINDEX). During the three highest electrical loading months at the three locations, the monthly accuracy varied from: 0% to 16% (DISC), 0% to 9% (DIRINT), and 0% to 8% (DIRINDEX). At one location different pyranometers were used to measure GHI, and the most expensive pyranometers did not improve the DNI model monthly accuracy. In lieu of actually measuring DNI, using the DIRINT model was felt to be sufficient for assessing whether to build a CSP plant at one location, but use of either the DIRINT or DIRINDEX models was felt to be marginal for the other two locations due to errors in modeling DNI for utility peak electrical loading days – especially for partly cloudy days. [Copyright &y& Elsevier]

Summary: The gradual deformation method (GDM) is a geostatistical parameterization technique introduced in reservoir engineering for compelling reservoir models to respect production history. It makes it possible to adjust the spatial distribution of the hydraulic properties populating the reservoir model so that the flow responses simulated for the modified model closely replicate the production data collected on the field. The work presented in this paper investigates the potential of the GDM to solve inverse problems in hydrogeology, or subsurface hydrology, and produce heterogeneous transmissivity fields conditional to both transmissivity and piezometric head measurements within a stochastic context. It focuses on the calibration of the Culebra Dolomite unit, which lies approximately 450m above the repository horizon of the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico, USA. Results show that the proposed version of the GDM, with a local deformation in each sub-domain neighboring a well, is efficient and competitive compared to other geostatistical-based inverse methods such as the pilot point method. [ABSTRACT FROM AUTHOR]

Abstract: This paper specifies and estimates state-level models of short- and long-term electricity demand in the United States. The short-term model predicts hourly load based on weather and calendar inputs. The long-term model estimates interannual demand, and includes population, prices, and gross state product as predictors. These models are combined to incorporate the short- and long-term trends in electricity consumption when generating forecasts of diurnal patterns into the future. Finally, the authors investigate the effects of short-run price elasticities of demand. The short-term model is shown to be within 95% accuracy of actual levels in out-of-sample tests. [Copyright &y& Elsevier]

Abstract: To demonstrate the greater capabilities and benefits achievable with a plug-in hybrid electric vehicle (PHEV), an energy optimization strategy for a power-split drivetrain PHEV, which utilizes a predicted speed profile, is presented. In addition, the paper reports an analysis and evaluation of issues related to real time control implementation for the modeled PHEV system, which include the optimization window sizes and the impact of prediction errors on the energy optimization strategy performance. The optimization time window sizes were identified and validated for different driving cycles under different operating modes and total length of travel. With the identified optimization windows size, improvements in fuel consumption were realized; the highest improvement was for Urban Dynamometer Driving Schedule (UDDS), with a range of improvement of 14–31%, followed by a 1–15% range of improvement for Highway Fuel Economy Driving Schedule (known as HWFET) and a 1–8% range of improvement for US06 (also known as Supplemental Federal Test Procedure). While no correlation was observed between the error rate and the rate of increased fuel consumption, this PHEV system still yielded energy savings with errors in the speed prediction, which is an indication of robustness of this PHEV model. [Copyright &y& Elsevier]

Abstract: In 2010 the United States implemented the Veterinary Medicine Loan Repayment Program (VMLRP) to address perceived regional shortages in certain veterinary occupations, including food animal practice. With county as the unit of analysis, this paper describes a pair of models to evaluate factors associated with being designated a private practice shortage area in 2010. One model is used to explain food animal veterinarian location choices so as to provide an objective evaluation of comparative shortage. The other model seeks to explain the counties chosen as shortage areas. Model results are then used to evaluate the program. On the whole the program appears to perform quite well. For several states, however, VMLRP shortage designations are inconsistent with the food animal veterinarian location model. Comparative shortage is generally more severe in states that have no VMLRP designated private practice shortage counties than in states that do. [Copyright &y& Elsevier]

Abstract: The Medicare program, which provides insurance coverage to the elderly in the United States, does not protect them fully against high out-of-pocket costs. For this reason private supplementary insurance, named Medigap, has been available to cover Medicare gaps. This paper studies how Medigap affects the utilization of inpatient care, separating the incentive and selection effects of supplementary insurance. For this purpose, we use two alternative estimation methods: a standard recursive bivariate probit and a discrete multivariate finite mixture model. We find that estimated incentive effects are modest and quite similar across models. There seems to be very significant selection, with the presence of both adversely and advantageously selected individuals, stemming from the multidimensional nature of residual heterogeneity. [Copyright &y& Elsevier]

Abstract: This paper describes the use of passive sampling systems and surrogate surfaces for monitoring atmospheric mercury (Hg) concentrations and dry deposition, respectively, in Florida,USA. Although this area has been reported to have low air concentrations, wet deposition values, reported by the Mercury Deposition Network, are some of the highest in the United States, and little is known about the magnitude of dry deposition to the region. To address this uncertainty, dry deposition of gaseous oxidized mercury (GOM) was estimated based on data collected using surrogate surfaces and through the application of a dry deposition model that utilized Tekran® Mercury Analyzer data for three sites (Davie near Fort Lauderdale, Tampa and Pensacola) over a year (July 2009-July 2010). Passive sampler systems for monitoring GOM and total gaseous mercury (TGM) concentrations were also deployed. In general, higher surrogate surface deposition, and GOM and TGM passive sampler uptake were observed at the DVE location. Across all sites, empirically derived dry deposition was higher than that determined using modeled values. Tekran® Instrument derived GOM concentrations, as well as modeled deposition rates, followed the same seasonal and spatial patterns as that measured by the samplers, however there were some spatial and temporal trends captured by the samplers that were not seen in the Tekran® derived data. Results indicate that these samplers may be applied to identify spatial and temporal trends in air Hg concentrations and potential deposition at sites with low and fairly constant GOM concentrations as reported by the Tekran® system (2–8pgm-3). When viewed collectively, trends in sampler and Tekran® derived data also suggest the potential for different forms of GOM in air. Using empirical and modeled values, dry deposition in Florida during the year of this study could account for 1.5 to 14% of total annual Hg deposition (wet+dry). [Copyright &y& Elsevier]

Abstract: This paper links Stolarsky mean apportionment methods, which include the US House of Representatives, the Saint-Lague, and the d’Hondt methods, to Kolm–Atkinson social welfare maximization and to generalized entropy minimization. Within this class, the logarithmic mean apportionment method is the most unbiased one that assigns at least one seat to each state. [Copyright &y& Elsevier]

Abstract: The US Army often operates heavy vehicles in rural areas, operating on low-volume roads having limited load carrying capacity. Many of these roads, such as the ones on the outskirts of Baghdad, have been raised to prevent flooding from nearby canals or irrigated fields. Sections of the roads have collapsed under the weight of armored vehicles, resulting in injuries and even fatalities. For the selected area studied, 2½% of the low-volume road sections were determined to be high risk given typical wheel loads of heavy vehicles for soil strength conditions modeled as low. The goal of the research was to develop a method for rapidly evaluating the stability of a road based on soil conditions, wheel load, and the dimensions of a vehicle. A model for road stability was developed to assist in performing analysis of the canal roads outside of Baghdad. This analysis was then used to create maps and charts characterizing road stability to assist the drivers. The procedure described in this paper can be used to evaluate elevated roads in other parts of the world. [Copyright &y& Elsevier]

Abstract: This paper examines the relationship between welfare reform and child care costs among low-income single mothers and the effects of post reform child care subsidy receipt on the status and duration of these mothers'' employment. A two-step model analysis of data from the Survey of Income and Program Participation (1993, 1996, and 2001 panels) revealed marginal effects of welfare reform on child care costs, indicating that child care costs increased significantly among low-income single mothers after welfare reform. Results from a Tobit model revealed that child care subsidy receipt also had significant effects on employment status. Finally, families with only a mother and children in the household had a higher probability of using paid child care and spent more on care than mothers with other adults in the household. [Copyright &y& Elsevier]

Abstract: This paper provides a solution to address one of the requirements identified in the US Northwest 6th Power Plan, specifically, meeting an increase in the forecasted Pacific Northwest demand with renewable generation. A model is presented which evaluates one source of renewable generation, off-shore wind energy. The model analyzes different wind turbine design characteristics, assigns significance to potential synergistic effects of one design feature on another, and provides an optimized design relative to the cost, environment, robustness, and overall efficiency of an off-shore wind turbine. [Copyright &y& Elsevier]

Abstract: Background: While drug abuse is the 10th leading cause of mortality in the US, the public health care system has been slow to adopt a chronic disease approach with aggressively timed monitoring and interventions. Drug abuse remains isolated from adoption into the “chronic condition” model of care. This paper evaluates the efficacy of quarterly Recovery Management Checkups (RMCs) on treatment reentry and long-term substance use in the context of chronic substance use disorders. Methods: 446 adult substance users were randomly assigned to RMC or a control group and assessed quarterly for 4 years (94% completion). The main outcome measures were: time from need of treatment to treatment reentry, frequency of treatment reentry, days of treatment, number of substance use related problems per month, and total days abstinent. Results: Participants in the RMC condition were significantly more likely than participants in the control group to return to treatment sooner, to return at all, to return more times, and to receive more total days of treatment. They subsequently had significantly fewer quarters in need of treatment, fewer substance related problems per month, and more total days of abstinence. Effects were larger for those with earlier onset and higher crime/violence scores. Conclusions: RMC is an effective method of monitoring and re-intervening with chronic substance users and is associated with improved long-term outcomes. A subgroup of people for whom RMC did not appear to be “enough,” signals a need to explore more intensive models to address chronicity. [Copyright &y& Elsevier]