Theory revision with queries: Horn, read-once, and parity formulas

A theory, in this context, is a Boolean formula; it is used to classify instances, or truth assignments. Theories can model real-world phenomena, and can do so more or less correctly. The theory revision, or concept revision, problem is to correct a given, roughly correct concept. This problem is considered here in the model of learning with equivalence and membership queries. A revision algorithm is considered efficient if the number of queries it makes is polynomial in the revision distance between the initial theory and the target theory, and polylogarithmic in the number of variables and the size of the initial theory. The revision distance is the minimal number of syntactic revision operations, such as the deletion or addition of literals, needed to obtain the target theory from the initial theory. Efficient revision algorithms are given for Horn formulas and read-once formulas, where revision operators are restricted to deletions of variables or clauses, and for parity formulas, where revision operators include both deletions and additions of variables. We also show that the query complexity of the read-once revision algorithm is near-optimal.     

Welding of Very Dissimilar Materials (Fe-Al)

Designers of transportation vehicles (air, land, or sea) continually seek ways to reduce vehicle weight in response to increasing fuel economy mandates, mission requirements, or other competitive pressures. One way to do this is by the selection of material types and their properties based on functional and structural requirements. While these material changes can help meet performance mandates, their implementation in a production environment relies on retaining economic competitiveness. This article traces the history of the various joining processes relevant to the current challenge in joining the very dissimilar families of steel (Fe) and aluminum (Al) alloys.     

Choosing Confrontation or Consensus in the Inner City: Lessons from a Community-University Partnership

This article describes the experiences of a Los Angeles inner-city neighbourhood in its attempt for revitalization. The authors headed a Community-University Partnership and worked with graduate students to offer technical support to a neighbourhood-based coalition. The students, local residents, merchants and neighbourhood institutions attempted to follow an asset-based consensus building approach to community development. The article describes the different components of their strategy for physical, economic, cultural and social revitalization, and analyzes the lessons learned from the successes and setbacks of this effort. Finally, the authors discuss some apparent limitations of the asset-based consensus approach.     

Trees and wood: working with natural river processes

A history of land clearance and riparian tree and wood management has resulted in limited riparian woodland and wood along British rivers. However, river management approaches are now being promoted that ‘work with natural processes’ to reduce flood risk through measures intended to restore, protect and emulate the natural function of catchments, rivers, estuaries and coasts. Wood has started to be reintroduced into river channels during river restoration and natural flood management activities, but this needs to be undertaken using appropriate quantities, locations and designs that mimic natural tree‐wood features. This paper reviews the knowledge that is needed to support wood reintroduction activities including (i) the characteristics of the riparian tree species and wood that are present; (ii) the importance of river size relative to that of trees and wood pieces; and (iii) the way trees, wood and geomorphic processes interact across rivers and floodplains of different energy and style.     

Rapid Quantitative Measurement of Extrusion-Induced Starch Fragmentation by Automated Gel Permeation Chromatography

Gel permeation chromatography with application of the universal calibration concept was found to be a rapid and effective method for quantification of extrusion-induced starch fragmentation. This method (Timpa. J.D., J. Agr. Food Chem. 39 (1991), 270–275) employs dimethyl acetamide (DMAC) with lithium chloride to solubilize samples and automated gel permeation chromatography for fractionation. Instrumentation was equipped with a viscometer and refractometer, data was interpreted by application of the universal calibration concept. These results confirm that the largest starch molecules in corn meal (107 to 108 Daltons) were slightly prone to fragmentation. Fragments produced were primarily in the weight range of 104–107 Daltons. In addition, some smaller fragments (ranging between 5,000 and 7.500) were also generated by extrusion.     

Development and hot-melt impregnation of a model controlled flow prepreg system

A controlled-flow epoxy-based model prepreg resin system was developed. The formulation of the model controlled-flow resin was designed from performance information obtained from a commercially available controlled-flow resin, presently used in the aircraft industry. Thermoanalytical techniques including rheometry were used to provide the necessary information to develop the model system along with a formulation methodology developed by Seferis and co-workers. The model resin formulation, which was a combination of tetraglycidyl ether of methylenedianiline (TGMDA), diglycidyl ether of bisphenol-A (DGEBA), carboxyl-modified butadiene/acrylonitrile rubber (CMBN), carboxyl-terminated butadiene/acrylonitrile rubber (CTBN), bisphenol-A (BPA), diaminodiphenyl sulfone (DDS), and dicyandiamide (DICY), was hot-melt impregnated into unidirectional carbon fibers on a laboratory scale hot-melt prepreg machine. A two-parameter, three-level design of experiments was performed on the prepreg processing parameters in which impregnation temperature and pressure were varied. Thus, a total of nine different experimental prepregs were produced and characterized by resin content, extent of impregnation, and tack. The results from the characterization of the nine experimental prepregs are compared with the effects of the prepreg processing conditions. These results are also compared with the results generated for the commercial controlled-flow resin. Collectively, this work provides a fundamental basis by which the analysis and rational utilization of controlled-flow matrix prepregs can be effected.     

Characteristics of Bi-metallic Interfaces Formed During Direct Energy Deposition Additive Manufacturing Processing

Metallurgical and Materials Transactions B - Various additive manufacturing processes are being evaluated to reduce the time and cost for fabrication of low volume, complex, and multifunctional...     

A randomized controlled trial of cognitive behavioral therapy for adherence and depression (CBT-AD) in HIV-infected individuals.

Objective: To evaluate cognitive-behavioral therapy to enhance medication adherence and reduce depression (CBT-AD) in individuals with HIV. Design: A two arm, randomized, controlled, cross-over trial comparing CBT-AD to enhanced treatment as usual only (ETAU). ETAU, which both groups received, included a single-session intervention for adherence and a letter to the patient's provider documenting her or his continued depression. The intervention group also received 10 to 12 sessions of CBT-AD. Main Outcome Measures: Adherence to antiretroviral therapy as assessed by Medication Event Monitoring Systems (MEMs) and depression as assessed by blinded structured evaluation. Results: At the acute outcome assessment (3-months), those who received CBT-AD evidenced significantly greater improvements in medication adherence and depression relative to the comparison group. Those who were originally assigned to the comparison group who chose to cross over to CBT-AD showed similar improvements in both depression and adherence outcomes. Treatment gains for those in the intervention group were generally maintained at 6- and 12-month follow-up assessments. By the end of the follow-up period, those originally assigned CBT-AD demonstrated improvements in plasma HIV RNA concentrations, though these differences did not emerge before the cross-over, and hence there were not between-groups differences. Conclusions: CBT-AD is a potentially efficacious approach for individuals with HIV struggling with depression and adherence. Replication and extension in larger efficacy trials are needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A continual improvement framework with integration of CMMI and six‐sigma model for auto industry

During the recent years, the major driving forces of customer preference, vehicle safety, environmental protection, and flat demand for new cars led to a proliferation of car models and associated price reduction in the auto supply chain. To react to the complex and competitive environment, auto suppliers are urgent to conduct continual improvement (CI) in an effective and systematic way. Thus, this paper presents a framework for CI. The Integrated Development System is proposed to integrate both capability maturity model integration and six‐sigma approach. By implementing the framework, an automaker can establish a solid process‐based management system, identify critical processes, and optimize these processes. For demonstrating the application of this framework, a case study is presented and the result shows that all expected processes' performance targets are achieved, which has dramatically improved by 70% compared with the past records. Apparently, the proposed framework would act as a useful reference to improve an organization's process maturity. Copyright © 2008 John Wiley & Sons, Ltd.     

US EPA's acute reference exposure methodology for acute inhalation exposures

The US Environmental Protection Agency (EPA) National Center for Environmental Assessment is engaged in the development of a methodology for Agency use to perform risk assessments for non-cancer effects due to acute inhalation exposures. The methodology will provide general guidance for deriving chemical-specific acute exposure benchmarks called acute reference exposures (AREs). Chemical-specific AREs are analogous to reference concentra tions (RfCs) for chronic non-cancer effects and will be incorporated in chemical-specific files in the US EPA's Integrated Risk Information System (IRIS) as they are developed and reviewed. AREs will have wide applicability in assessing the potential health risks of accidental and routine acute releases of chemicals to the environment. The proposed methodology for ARE development provides a framework for choosing an optimal derivation approach, depending on the type of data available, from the no-observed-adverse-effect level (NOAEL), benchmark concentration (BMC), or categorical regression approaches. Uncertainty factors are applied to the point of departure, determined by one of the recommended approaches, to derive the ARE. Due to the capability to use more exposure-response information than the NOAEL approach allows, exposure-response analyses such as BMC and categorical regression are favored as methods to develop the point of departure when the available database will support such analyses. The NOAEL approach is suitable when the data are insufficient to support exposure-response modeling. Applications of the proposed ARE methodology are illustrated by the derivation of example AREs for hydrogen sulfide and hexachlorocyclopentadiene, which showcase the categorical regression and NOAEL approaches, respectively. In addition, a recent review of the proposed ARE methodology by the US EPA Risk Assessment Forum is discussed.