A free-boundary model of diffusive valley growth: theory and observation

Valleys that form around a stream head often develop characteristic finger-like elevation contours. We study the processes involved in the formation of these valleys and introduce a theoretical model that indicates how shape may inform the underlying processes. We consider valley growth as the advance of a moving boundary travelling forward purely through linearly diffusive erosion, and we obtain a solution for the valley shape in three dimensions. Our solution compares well to the shape of slowly growing groundwater-fed valleys found in Bristol, Florida. Our results identify a new feature in the formation of groundwater-fed valleys: a spatially variable diffusivity that can be modelled by a fixed-height moving boundary

Morbig: A Static Parser for POSIX Shell

International audienceThe POSIX shell language defies conventional wisdom of compiler construction on several levels: The shell language was not designed for static parsing, but with an intertwining of syntactic analysis and execution by expansion in mind. Token recognition cannot be specified by regular expressions, lexical analysis depends on the parsing context and the evaluation context, and the shell grammar given in the specification is ambiguous. Besides, the unorthodox design choices of the shell language fit badly in the usual specification languages used to describe other programming languages. This makes the standard usage of Lex and Yacc as a pipeline inadequate for the implementation of a parser for POSIX shell. The existing implementations of shell parsers are complex and use low-level character-level parsing code which is difficult to relate to the POSIX specification. We find it hard to trust such parsers, especially when using them for writing automatic verification tools for shell scripts.This paper offers an overview of the technical difficulties related to the syntactic analysis of the POSIX shell language. It also describes how we have resolved these difficulties using advanced parsing techniques (namely speculative parsing, parser state introspection, context-dependent lexical analysis and longest-prefix parsing) while keeping the implementation at a sufficiently high level of abstraction so that experts can check that the POSIX standard is respected. The resulting tool, called Morbig, is an open-source static parser for a well-defined and realistic subset of the POSIX shell language

A study to determine the causes of accidents: an in-depth case report case no. TAC-SP-75-6, school bus/garbage truck - acute oblique. Final report.

National Highway Traffic Safety Administration, Washington, D.C.Mode of access: Internet.COP: 2Author corporate affiliation: Indiana University, Bloomington, Institute for Research in Public SafetySubject code: DEDSSubject code: DEHSubject code: DGESSubject code: JLKSubject code: MAFSubject code: NVWSubject code: YC

Tri-level study of the causes of traffic accidents: final report. Executive summary.

Report covers the period Aug 1972-June 1977. Released Oct 1979. Contract amount - $1,531,466Technical Volume I reports causal factor tabulations from Phases II through V (1972-75). Volume II reports analysis tasks dealing with driver vision, knowledge, psychological make-up, etc. Additional analysis tasks conducted under a contract modification are reported in six separate volumes. Data were collected on three levels. Police reports and other baseline data on the Monroe County, Indiana study area were collected on Level A. On Level B, teams of technicians responded to accidents at the time of their occurrence to conduct on-scene investigations; a total of 2,258 investigations were conducted during Phases II through V. Concurrently, 420 of these accidents were independently examined by a multidisciplinary team on Level C. General population surveys were also conducted. Human factors were cited by the in-depth team as probable causes in 92.6% of accidents investigated in Phases II through V. Environmental factors were cited as probable cause in 33.8% of these accidents, while vehicular factors were identified as probably causes in 12.6%. The major human direct causes were improper lookout, excessive speed, in attention, improper evasive action, and internal distraction. Leading environmental causes were view obstructions and slick roads. The major vehicular causes were brake failure, inadequate tread depth, side-to-side brake imbalance, under-inflation, and vehicle-related vision obstructions. Vision (especially poor dynamic visual acuity) and personality (especially poor personal and social adjustment) were found related to accident-involvement. However, as measured in this study, knowledge of the driving task was not shown to be related.U.S. Department of Transportation, Washington, D.C.http://deepblue.lib.umich.edu/bitstream/2027.42/64993/1/43120.pd

Benchmarking Implementations of Term Rewriting and Pattern Matching in Algebraic, Functional, and Object-Oriented Languages - The 4th Rewrite Engines Competition

International audienceMany specification and programming languages have adopted term rewriting and pattern matching as a key feature. However, implementation techniques and observed performance greatly vary across languages and tools. To provide for an objective comparison, we developed an open, experimental platform based upon the ideas of the three Rewrite Engines Competitions (2006, 2008, and 2010), which we significantly enhanced, extended, and automated. We used this platform to benchmark interpreters and compilers for a number of algebraic, functional, and object-oriented languages, and we report about the results obtained for CafeOBJ, Clean, Haskell, LNT, LOTOS, Maude, mCRL2, OCaml, Opal, Rascal, Scala, SML (MLton and SML-NJ), Stratego/XT, and Tom

Occupational Exposures and Thyroid Cancer

Thyroid cancer accounts for the majority of endocrine cancers, and the number of cases is increasing worldwide likely due to increased recognition more than a real increment of the disease. Exposure to ionizing radiation is the main occupational exposure related to thyroid cancer. Several studies were carried out on Chernobyl cleanup workers and healthcare professionals exposed to ionizing radiation. These reported a causal relationship between acute or cumulative exposure to moderate/high radiation dose and thyroid cancer, while there is less clear evidence that chronic exposure to low dose increases the risk. However, the excess risk reported in the majority of studies is likely overestimated because of a higher surveillance among workers whose activity entails exposure to ionizing radiation. Epidemiological studies on other occupational risks are scarce, and it is not possible to draw firm conclusions on other exposure agents, including pesticides, benzene, and formaldehyde as well as on workers employed in semiconductor, wood, paper, and textile industries