Re-examination of seven-dimensional site percolation thresholds

Monte Carlo simulations alone could not clarify the corrections to scaling for the size-dependent p_c(L) above the upper critical dimension. Including the previous series estimate for the bulk threshold $p_c(\infty)$ gives preference for the complicated corrections predicted by renormalization group and against the simple 1/L extrapolation. Additional Monte-Carlo simulations using the Leath method corroborate the series result for p_c.Comment: 3 pages, 3 figures, submitte

Fire suppression in human-crew spacecraft

Fire extinguishment agents range from water and foam in early-design spacecraft (Halon 1301 in the present Shuttle) to carbon dioxide proposed for the Space Station Freedom. The major challenge to spacecraft fire extinguishment design and operations is from the micro-gravity environment, which minimizes natural convection and profoundly influences combustion and extinguishing agent effectiveness, dispersal, and post-fire cleanup. Discussed here are extinguishment in microgravity, fire-suppression problems anticipated in future spacecraft, and research needs and opportunities

Scalable Applications on Heterogeneous System Architectures: A Systematic Performance Analysis Framework

The efficient parallel execution of scientific applications is a key challenge in high-performance computing (HPC). With growing parallelism and heterogeneity of compute resources as well as increasingly complex software, performance analysis has become an indispensable tool in the development and optimization of parallel programs. This thesis presents a framework for systematic performance analysis of scalable, heterogeneous applications. Based on event traces, it automatically detects the critical path and inefficiencies that result in waiting or idle time, e.g. due to load imbalances between parallel execution streams. As a prerequisite for the analysis of heterogeneous programs, this thesis specifies inefficiency patterns for computation offloading. Furthermore, an essential contribution was made to the development of tool interfaces for OpenACC and OpenMP, which enable a portable data acquisition and a subsequent analysis for programs with offload directives. At present, these interfaces are already part of the latest OpenACC and OpenMP API specification. The aforementioned work, existing preliminary work, and established analysis methods are combined into a generic analysis process, which can be applied across programming models. Based on the detection of wait or idle states, which can propagate over several levels of parallelism, the analysis identifies wasted computing resources and their root cause as well as the critical-path share for each program region. Thus, it determines the influence of program regions on the load balancing between execution streams and the program runtime. The analysis results include a summary of the detected inefficiency patterns and a program trace, enhanced with information about wait states, their cause, and the critical path. In addition, a ranking, based on the amount of waiting time a program region caused on the critical path, highlights program regions that are relevant for program optimization. The scalability of the proposed performance analysis and its implementation is demonstrated using High-Performance Linpack (HPL), while the analysis results are validated with synthetic programs. A scientific application that uses MPI, OpenMP, and CUDA simultaneously is investigated in order to show the applicability of the analysis

Pollution Limits and Polluters’ Efforts to Comply: The Role of Government Monitoring and Enforcement

This is the first chapter of a book published in 2011 by Stanford University Press that examines empirically compliance with regulatory obligations under the Clean Water Act (CWA). In particular, it examines four dimensions of federal water-pollution control policy in the United States: pollution limits imposed on industrial facilities’ pollution discharges; facilities’ efforts to comply with pollution limits, identified as “environmental behavior”; facilities’ success at controlling their discharges to comply with pollution limits, identified as “environmental performance”; and regulators’ efforts to induce compliance with pollution limits in the form of inspections and enforcement actions, identified as “government interventions.” The authors gather and analyze data on environmental performance and government interventions from Environmental Protection Agency (EPA) databases, and data on environmental behavior gathered from their own survey distributed to 1,003 chemical manufacturing facilities permitted to discharge wastewater in 2002. By analyzing links between critical elements in the puzzle of enforcement of and compliance with environmental protection laws, the book speaks to several straightforward, but important, policy-relevant research questions: Do government interventions help induce better environmental behavior and/or better environmental performance? Do tighter pollution limits improve environmental behavior and/or performance? And, does better environmental behavior lead to better environmental performance

Depiction of the Regulator-Regulated Entity Relationship in the Chemical Industry: Deterrence-Based V. Cooperative Enforcement

For years, scholars and environmental policymakers have conducted a spirited debate about the comparative merits of two different approaches to enforcement of the nation\u27s environmental laws - the coercive (or deterrence-based) and cooperative approaches. Supporters of the coercive model regard the deterrence of violations as the fundamental purpose of environmental enforcement. These supporters also regard the imposition of sanctions, which make it less costly for regulated entities to comply with their regulatory responsibilities and avoid enforcement than to fail to comply and run the risk of enforcement, as the most effective way for inducing regulated entities to comply with their regulatory obligations. Supporters of the cooperative approach to environmental enforcement focus more on compliance than deterrence. The cooperative approach, which emphasizes the provision of compliance assistance and incentives by regulatory agencies, operates on the premise that regulated entities react to a variety of motives that supply sufficient incentives to comply with regulatory obligations even without an overly punitive approach to enforcement. They contend that a coercive approach to enforcement may even be counterproductive if it engenders intransigence and ill will on the part of regulated entities. Few studies empirically test these competing theories about how best to induce environmental compliance. Our study, which is based on a survey we conducted of chemical manufacturing facilities that are regulated under the federal Clean Water Act, represents an effort to begin addressing the paucity of information on the effects of the two enforcement approaches on environmental compliance and behavior. Our study indicates that, although most of the respondents in our survey describe the relationships they have with their CWA regulators as generally either cooperative or coercive, they also report that some particular aspects of their relationships are more consistent with one enforcement approach, while other aspects are more consistent with the other enforcement approach. Our study calculates and interprets the correlations between all of the various aspects of the regulator-regulated entity relationship, especially the overall type of relationship - coercive versus cooperative. The results reveal only weak correlation between the various measures capturing the relationship between the regulator and the regulated entity. As an alternative means for depicting the weak connection between relationship aspects, we also cross-tabulate the responses to all possible pairs of relationship aspects. This analysis reveals less than complete overlap between the various measures capturing the relationship between the regulator and the regulated entity. We conclude that the relationship between a regulator and a regulated entity consists of multiple dimensions - no single underlying dimension seems to reflect all of the ways in which regulators and regulated entities interact. For years, scholars and environmental policymakers have conducted a spirited debate about the comparative merits of two different approaches to enforcement of the nation\u27s environmental laws - the coercive (or deterrence-based) and cooperative approaches. Supporters of the coercive model regard the deterrence of violations as the fundamental purpose of environmental enforcement. These supporters also regard the imposition of sanctions, which make it less costly for regulated entities to comply with their regulatory responsibilities and avoid enforcement than to fail to comply and run the risk of enforcement, as the most effective way for inducing regulated entities to comply with their regulatory obligations. Supporters of the cooperative approach to environmental enforcement focus more on compliance than deterrence. The cooperative approach, which emphasizes the provision of compliance assistance and incentives by regulatory agencies, operates on the premise that regulated entities react to a variety of motives that supply sufficient incentives to comply with regulatory obligations even without an overly punitive approach to enforcement. They contend that a coercive approach to enforcement may even be counterproductive if it engenders intransigence and ill will on the part of regulated entities. Few studies empirically test these competing theories about how best to induce environmental compliance. Our study, which is based on a survey we conducted of chemical manufacturing facilities that are regulated under the federal Clean Water Act, represents an effort to begin addressing the paucity of information on the effects of the two enforcement approaches on environmental compliance and behavior. Our study indicates that, although most of the respondents in our survey describe the relationships they have with their CWA regulators as generally either cooperative or coercive, they also report that some particular aspects of their relationships are more consistent with one enforcement approach, while other aspects are more consistent with the other enforcement approach. Our study calculates and interprets the correlations between all of the various aspects of the regulator-regulated entity relationship, especially the overall type of relationship - coercive versus cooperative. The results reveal only weak correlation between the various measures capturing the relationship between the regulator and the regulated entity. As an alternative means for depicting the weak connection between relationship aspects, we also cross-tabulate the responses to all possible pairs of relationship aspects. This analysis reveals less than complete overlap between the various measures capturing the relationship between the regulator and the regulated entity. We conclude that the relationship between a regulator and a regulated entity consists of multiple dimensions - no single underlying dimension seems to reflect all of the ways in which regulators and regulated entities interact

The Comparative Effectiveness of Government Interventions on Environmental Performance in the Chemical Industry

Effective enforcement is crucial to achieving the objectives of the federal environmental statutes. The federal Environmental Protection Agency (EPA) has recognized the importance of effective enforcement, calling it a critical aspect of environmental governance and committing itself to the maintenance of a credible deterrent to regulatory violations. Despite the central role of enforcement to achievement of environmental statutory goals, relatively little is known about why regulated entities either do or do not comply. In particular, empirical studies of environmental enforcement are not plentiful, in part because comprehensive data on compliance and enforcement have been difficult to obtain. Although EPA and state environmental agencies typically assume that rigorous enforcement will deter noncompliance, some environmental law experts have asserted that available evidence suggests that sanctions do not play a major role in inducing compliance with environmental regulations. Even assuming that government enforcement efforts do generally induce regulated firms to improve their performance, relatively little is known about what kinds of enforcement actions are more effective at deterring noncompliance than others. Perhaps for these reasons, EPA has expressed an interest in learning more about the relative effectiveness of different forms of government interventions (including inspections, monetary fines, injunctive relief sanctions, and supplemental environmental projects) on the performance of regulated entities. EPA has stated, for example, that empirical research on the comparative effectiveness of these interventions is critical because it will create data sources needed to assess the degree to which each of the interventions affects environmental performance. This article responds to the need for additional insights into the comparative effectiveness of government interventions on the environmental performance of regulated entities by focusing on facilities in the chemical industry that are regulated under the federal Clean Water Act (CWA). The article assesses whether some interventions are likely to be more or less effective than others in improving environmental performance on the basis of two related analyses. First, the article analyzes the effects of specific deterrence, as stemming from actual interventions, and general deterrence, as stemming from the threat of interventions, on the level of discharges relative to facility-specific effluent limitations. Second, the article analyzes the self-reported perceptions of intervention efficacy provided as responses to a survey administered to facilities in the same industry. The article describes our findings on the comparative effectiveness of government interventions on the performance of point sources in the chemical industry subject to CWA permit requirements, and places those findings in the context of the theoretical literature on environmental compliance and previous empirical studies on the effects of government interventions on environmental performance

Depiction of the Regulator-Regulated Entity Relationship in the Chemical Industry: Deterrence-Based V. Cooperative Enforcement

For years, scholars and environmental policymakers have conducted a spirited debate about the comparative merits of two different approaches to enforcement of the nation\u27s environmental laws - the coercive (or deterrence-based) and cooperative approaches. Supporters of the coercive model regard the deterrence of violations as the fundamental purpose of environmental enforcement. These supporters also regard the imposition of sanctions, which make it less costly for regulated entities to comply with their regulatory responsibilities and avoid enforcement than to fail to comply and run the risk of enforcement, as the most effective way for inducing regulated entities to comply with their regulatory obligations. Supporters of the cooperative approach to environmental enforcement focus more on compliance than deterrence. The cooperative approach, which emphasizes the provision of compliance assistance and incentives by regulatory agencies, operates on the premise that regulated entities react to a variety of motives that supply sufficient incentives to comply with regulatory obligations even without an overly punitive approach to enforcement. They contend that a coercive approach to enforcement may even be counterproductive if it engenders intransigence and ill will on the part of regulated entities. Few studies empirically test these competing theories about how best to induce environmental compliance. Our study, which is based on a survey we conducted of chemical manufacturing facilities that are regulated under the federal Clean Water Act, represents an effort to begin addressing the paucity of information on the effects of the two enforcement approaches on environmental compliance and behavior. Our study indicates that, although most of the respondents in our survey describe the relationships they have with their CWA regulators as generally either cooperative or coercive, they also report that some particular aspects of their relationships are more consistent with one enforcement approach, while other aspects are more consistent with the other enforcement approach. Our study calculates and interprets the correlations between all of the various aspects of the regulator-regulated entity relationship, especially the overall type of relationship - coercive versus cooperative. The results reveal only weak correlation between the various measures capturing the relationship between the regulator and the regulated entity. As an alternative means for depicting the weak connection between relationship aspects, we also cross-tabulate the responses to all possible pairs of relationship aspects. This analysis reveals less than complete overlap between the various measures capturing the relationship between the regulator and the regulated entity. We conclude that the relationship between a regulator and a regulated entity consists of multiple dimensions - no single underlying dimension seems to reflect all of the ways in which regulators and regulated entities interact. For years, scholars and environmental policymakers have conducted a spirited debate about the comparative merits of two different approaches to enforcement of the nation\u27s environmental laws - the coercive (or deterrence-based) and cooperative approaches. Supporters of the coercive model regard the deterrence of violations as the fundamental purpose of environmental enforcement. These supporters also regard the imposition of sanctions, which make it less costly for regulated entities to comply with their regulatory responsibilities and avoid enforcement than to fail to comply and run the risk of enforcement, as the most effective way for inducing regulated entities to comply with their regulatory obligations. Supporters of the cooperative approach to environmental enforcement focus more on compliance than deterrence. The cooperative approach, which emphasizes the provision of compliance assistance and incentives by regulatory agencies, operates on the premise that regulated entities react to a variety of motives that supply sufficient incentives to comply with regulatory obligations even without an overly punitive approach to enforcement. They contend that a coercive approach to enforcement may even be counterproductive if it engenders intransigence and ill will on the part of regulated entities. Few studies empirically test these competing theories about how best to induce environmental compliance. Our study, which is based on a survey we conducted of chemical manufacturing facilities that are regulated under the federal Clean Water Act, represents an effort to begin addressing the paucity of information on the effects of the two enforcement approaches on environmental compliance and behavior. Our study indicates that, although most of the respondents in our survey describe the relationships they have with their CWA regulators as generally either cooperative or coercive, they also report that some particular aspects of their relationships are more consistent with one enforcement approach, while other aspects are more consistent with the other enforcement approach. Our study calculates and interprets the correlations between all of the various aspects of the regulator-regulated entity relationship, especially the overall type of relationship - coercive versus cooperative. The results reveal only weak correlation between the various measures capturing the relationship between the regulator and the regulated entity. As an alternative means for depicting the weak connection between relationship aspects, we also cross-tabulate the responses to all possible pairs of relationship aspects. This analysis reveals less than complete overlap between the various measures capturing the relationship between the regulator and the regulated entity. We conclude that the relationship between a regulator and a regulated entity consists of multiple dimensions - no single underlying dimension seems to reflect all of the ways in which regulators and regulated entities interact