Verbing the noun [software development]

Software development seems to be a discipline of artifacts; the developers spend their time producing products and attempting to find ways to measure just how well and how fast they make that product. We get pleasure from the act of creation and from activities that surround the creation process. But as time goes on, we start to lose sight of this. Companies are not interested in the process as much as the product. Managers cannot measure the thought that goes into a specification; they only see the document.     

Renaming Detection

Finding changed identifiers is important for understanding the difference between two versions of a program and for detecting and resolving conflicts while merging variants of a program together. Standard practice for differencing and merging relies on line based techniques that do not recognize renamed identifiers. The design and implementation of a tool to automatically detect renamed identifiers between two versions of a program is presented. The system uses an abstract representation of language constructs to enable language awareness without introducing language dependence. Modules for Java and Scheme have been written. The detector works with multiple file pairs, taking into account renamings that span several files. A case study is presented that demonstrates proof of concept. The detector is part of a suite of intelligent differencing and merging programs that exploit the static semantics of programming languages.     

Stable inversion and parameter variations

As part of the process of automatically guiding an aircraft, we have been successful in using stable inversion to compute a desired bounded state trajectory and corresponding bounded control. In addition to this feedforward control, we must also construct a regulator to address modeling errors and disturbances. With respect to modeling errors we find that the stable inversion procedures used are so accurate that the regulator can assume a simple form, say a linear regulator about the desired trajectory. We show that under the appropriate assumptions, the bounded state trajectory and bounded control computed through stable inversion depend continuously on the parameters of the system. This is a consequence of a mathematical result that we prove about the continuous dependence of the “particular solution” of a time varying nonlinear system driven by a bounded input. This is distinct from the usual continuous dependence of the initial value problem for systems.     

Performance Comparison of Four Fiber-Reinforced Polymer Deck Panels

In an effort to assess the constructability and performance of bridges with fiber-reinforced polymer (FRP) composite decks, the short-term and long-term responses of a 207 m, five-span bridge retrofitted with four different FRP panel systems were monitored. The overall aspects of the panel systems, connection details, and construction techniques are presented prior to presentation of the observed and measured responses. Key design parameters (impact factors, girder distribution factors, and level of composite action) for FRP and reinforced concrete decks are evaluated. This paper demonstrates that FRP replacement decks are a viable alternative to reinforced concrete decks and identifies the differences in performances of various FRP deck systems. Two of the FRP panel systems were found to perform considerably better than the other deck systems. Issues that may reduce the service life of FRP deck systems are presented and discussed.     

Evaluation of Four Permeable Pavement Sites in Eastern North Carolina for Runoff Reduction and Water Quality Impacts

Four permeable pavement applications in North Carolina’s Coastal Plain were constructed and monitored to determine their effectiveness of reducing runoff quantity and improving water quality. Sites were either constructed of permeable interlocking concrete pavers (2), porous concrete (1), or concrete grid pavers (1). One site of each pavement type was monitored for runoff reduction for periods ranging from 10 to 26 months. Measured runoff depths from rainfall events over 50?mm were used to determine permeable pavement equivalent curve numbers for the sites, which ranged from 45 to 85. Only the two permeable interlocking concrete pavement (PICP) sites were monitored for water quality. Runoff and exfiltrate samples were intended to be collected, in addition to runoff monitoring, from the Swansboro PICP site. However, no runoff was produced during this study from the Swansboro PICP site for rainfall events up to 88?mm. From exfiltrate concentrations, nutrient retention was estimated to be 3.4 and 0.4?kg/ha/year for total nitrogen and total phosphorus, respectively. For the Goldsboro PICP site, water quality of asphalt runoff and PICP exfiltrate were compared. Analysis of water quality samples from the second site determined that concentrations of total Kjeldahl nitrogen, ammonia, total phosphorus, and zinc were significantly (p ? 0.05) lower in permeable pavement exfiltrate than asphalt runoff.     

Subtelomeric sequence from the right arm of Schizosaccharomyces pombe chromosome I contains seven permease genes

The sequence has been determined of 80 888 bp of contiguous subtelomeric DNA, including the isp5 gene, from the right arm of chromosome I of Schizosaccharomyces pombe; 27 open reading frames (ORFs) longer than 100 codons are present, giving a density of one gene per 3.0 kb. Seven of the predicted proteins are members of the major facilitator superfamily (MFS) of transport proteins, including four amino acid permease homologues, bringing this family of amino acid permease sequences to 17 in Sz. pombe, and a phylogenetic analysis is presented. Also encoded is an allantoate permease homologue, a sulphate permease homologue and a probable urea active transporter. Predicted non-membrane proteins include a 1-aminocyclopropane-1-carboxylate deaminase (ACC deaminase), a class III aminotransferase, serine acetyltransferase, protein-L-isoaspartate O-methyltransferase, alpha-glucosidase, alpha-galactosidase, esterase/lipase, oxidoreductase of the short-chain dehydrogenase/reductase (SDR) family, aldehyde dehydrogenase, formamidase, amidase, flavohaemoprotein, a putative translation initiation inhibitor and a protein with similarity to a filamentous fungal conidiation-specific protein. The remaining six ORFs are likely to encode proteins, either because they have sequence similarity with hypothetical proteins or because they are known to be transcribed. Introns are scarce in the sequenced region: only three ORFs contain introns, with only one having multiple introns. The sequenced region also contains a single Tf1 transposon long terminal repeat (LTR). The sequence is derived from cosmid clones c869, c922 and c1039 and has been submitted to the EMBL database under entries SPAC869 (Accession No. AL132779), SPAC922 (AL133522) and SPAC1039 (AL133521).     

Statewide investigation of the role of pyrethroid pesticides in sediment toxicity in California's urban waterways

A statewide investigation of urban creek sediment toxicity was conducted in California in recognition of increased incidences of toxicity linked to pyrethroid pesticides. The goals were to examine the spatial occurrence and magnitude of sediment toxicity in California urban creeks, and to examine the role of pyrethroids in toxic urban creek sediment samples. After a preliminary screening of 90 sites, 30 creeks were sampled in eight geographical regions. Sediment toxicity was assessed using 10 day bioassays with the resident amphipod Hyalella azteca. Bioassays were conducted at two test temperatures of 23 degrees C and at 15 degrees C to provide evidence of the cause of toxicity, and to more accurately reflect ambient environmental temperatures. Twenty-five of 30 samples were toxic when tested at 23 degrees C, and all 30 samples were toxic when tested at 15 degrees C. The magnitude of toxicity increased in samples tested at 15 degrees C suggesting the influence of pyrethroids, which are more toxic at colder temperatures. Pyrethroids were present in all sediment samples and were the only compounds detected at concentrations toxic to H. azteca. Bifenthrin was the pyrethroid of greatest toxicological concern, occurring in all 30 samples at concentrations up to 219 ng/g. Pyrethroid contamination of urban creeks was most severe in the Los Angeles, Central Valley, and San Diego regions, respectively. However, pyrethroids were also linked to urban creek aquatic toxicity in all regions sampled, including the less urbanized areas of the North Coast and Lake Tahoe.     

用概率统计方法增强结构木质复合材料的竞争力

Hunt在1976年曾撰文呼吁,重视结构用刨花板(主要为大片刨花板)的广泛应用及结构可靠性设计方法的引入,为木质复合材料工业发展带来了大好局面。他认为具有更高稳定性的建筑材料,特别是如工程复合材料之类,可以通过改善设计、工艺过程和质量控制等方式来提高其质量稳定性;通过以可靠性为基础的设计方式