Dual Allegiance and Knowledge Sharing in Open Source Software Firms

Employees of commercial software firms who participate in open source software projects are found to be allegiant to both their company and the open source community. In this paper we examine how these employees' dual allegiance influences their knowledge sharing behaviour. We adopt Husted and Michailova's model on dual allegiance and knowledge sharing in inter‐firm R&D collaborations to the context of open source software firms. We argue that the type of allegiance the individual holds towards their employing firm and the open source community has a strong influence of how they share knowledge with other community members. We use the examples of two open source software firms in New Zealand to ground the empirical inspiration of our paper and to illustrate our key ideas and arguments. We discuss the knowledge governance challenges imposed by employees' dual allegiance and how managers of open source software firms can balance the demands of the open source community and the interests of the clients.     

Anomalously Low Surface Area and Density in the Silica—Alumina Gel System

A range of composition/processing conditions that yield xerogel surface areas 2 orders of magnitude lower than expected along with low skeletal densities has been discovered. For xerogel compositions in the vicinity of 50 wt% Al₂O₃, surface areas are 1 to 5 m²/g and skeletal densities are 2.1 to 2.2 g/cm³, as compared to the expected values of ∼300 m²/g and ∼2.6 g / cm³, respectively. This behavior is observed over a wide range of heat treatment temperatures (373 to 1073 K) and appears to be the result of closed porosity which evolves during gel drying.     

Comments on Gresham, MacMillan, and Siperstein's paper "Critical analysis of the 1992 AAMR definition: Implications for school psychology."

Commends F. M. Gresham et al (see record 1995-37454-001) for their critical analysis of the 1992 definition of mental retardation written by the American Association on Mental Retardation (AAMR). The AAMR appears to have abandoned a pragmatic/scientific definition in favor of one that is primarily political, espousing a "rights" philosophy which has become prominent in the general field of developmental disabilities. The approach of the AAMR appears to be antithetical to science and may promote more inaccuracies in diagnoses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Automated discovery of concise predictive rules for intrusion detection

This paper details an essential component of a multi-agent distributed knowledge network system for intrusion detection. We describe a distributed intrusion detection architecture, complete with a data warehouse and mobile and stationary agents for distributed problem-solving to facilitate building, monitoring, and analyzing global, spatio-temporal views of intrusions on large distributed systems. An agent for the intrusion detection system, which uses a machine learning approach to automated discovery of concise rules from system call traces, is described.

We use a feature vector representation to describe the system calls executed by privileged processes. The feature vectors are labeled as good or bad depending on whether or not they were executed during an observed attack. A rule learning algorithm is then used to induce rules that can be used to monitor the system and detect potential intrusions. We study the performance of the rule learning algorithm on this task with and without feature subset selection using a genetic algorithm. Feature subset selection is shown to significantly reduce the number of features used while improving the accuracy of predictions.     

On Staleness and the Delivery of Web Pages

A popular technique to improve the scalability of a web based system is caching at proxy servers. Caching has the drawback that a cached page becomes stale when the page is updated at the web server. In some cases, staleness may not be completely avoided because the server may not wish to expend the processing and communication resources required to transmit all the updates immediately. In general, if updates are transmitted less frequently, the staleness will tend to increase, but the amount of resources consumed will be reduced. The tradeoff between resource consumption and staleness is investigated. A measure of staleness is defined and optimization problems are formulated. The solutions to these problems allow one to come up with an optimal strategy for transmitting page updates. Numerical examples showing the resource consumption/staleness tradeoff are presented.     

Municipal wastewater treatment by biofiltration: comparisons of various treatment layouts. Part 1: assessment of carbon and nitrogen removal

One of the largest wastewater treatment plants in the Paris conurbation (240,000 m(3)/d) has been studied over several years in order to provide technical and economical information about biological treatment by biofiltration. Biofiltration systems are processes in which carbon and nitrogen pollution of wastewater are treated by ascendant flow through immersed fixed cultures. This paper, focused on technical information, aims: (1) to compare performances of the three biological treatment layouts currently used in biofiltration systems: upstream denitrification (UD), downstream denitrification (DD) and combined upstream-downstream denitrification (U-DD) layouts; and (2) to describe in detail each treatment step. Our study has shown that more than 90% of the carbon and ammoniacal pollution is removed during biological treatment, whatever the layout used. Nitrate, produced during nitrification, is then reduced to atmospheric nitrogen. This reduction is more extensive when the denitrification stage occurs downstream from the treatment (DD layout with methanol addition), whereas it is only partial when it is inserted upstream from the treatment (UD layout - use of endogenous carbonaceous substrate). So, the UD layout leads to a nitrate concentration that exceeds the regulatory threshold in the effluent, and the treatment must be supplemented with a post-denitrification step (U-DD layout). Our work has also shown that the optimal ammonium-loading rate is about 1.1-1.2 kg N-NH(4)(+) per m(3) media (polystyrene) and day. For denitrification, the optimal nitrate-loading rate is about 2.5 kg N per m(3) media (expanded clay) and day in the case of DD with methanol, and is about 0.25 kg N-NO(3)(-) per m(3) media and day in the case of UD with exogenous carbonaceous substrate.     

Logic Synthesis with High Speed CMOS Circuit Techniques

Systems for automated logic synthesis with the True Single Phase Clocking circuit technique (TSPC) and a modified form of the Clock and Data Precharged Dynamic (CDPD) circuit technique, are presented. The CDPD system synthesizes high speed one clock cycle modules of unate Boolean functions in short design time. A novel true single phase clocking (TSPC) flip-flop suitable for CDPD synthesis simplifies interfacing with standard edge triggered clocking schemes. Also, a TSPC cell library for automatic logic synthesis with the TSPC circuit technique is presented. The library is targeted for high performance DSP applications. Fabricated test circuits synthesized by both the CDPD and TSPC synthesis systems in a 0.8m standard CMOS process are described and their performance is verified. Clock frequencies up to 700MHz were measured.     

Effect of conversion of natural grassland to cropland on nitric oxide emissions from Venezuelan savanna soils. A four-year monitoring study

Conversion of “natural” savanna to agricultural soil is proceeding at a very fast rate. In this work, nitric oxide (NO) emissions were measured immediately after conversion of a “natural” grassland to fertilized agricultural fields (corn, sorghum and cultivated pasture), and also during the second and fourth year after conversion. Large fluxes were observed after plowing grassland soil, and almost no difference was observed between ammonium-fertilized and unfertilized plowed grassland soils. Soil water content and pH related negatively to NO emissions. NO emissions were positively correlated with soil nitrate concentrations and carbon content (corn only) whereas little or no correlation was found with ammonium concentrations. This suggests that in these savanna soils, the NO emitted from soil is mainly denitrification-derived. The disturbed soils emitted on average ∼7 times more NO than the original grassland. During the second and fourth year of cultivation the emissions from corn and sorghum fields (plowed every year) were around 10 times higher than from the control grassland soils. The fertilizer-induced emission (FEI) values for NO emission estimated in this work show that similar agricultural practices could lead to dramatically different FEI values depending on the water content of the soils. These FEI results corroborates that modeling approaches to determine the global agriculture-derived NO emissions should take into consideration the main factors that regulate the NO emission at the scale of functional units with similar climate, soil and management conditions instead of expressing it as a percentage of the fertilizer applied. In our sandy loam savanna soils these factors are inorganic nitrogen content, pH and WFPS.