Three-weight codes over rings and strongly walk regular graphs

We construct strongly walk-regular graphs as coset graphs of the duals of codes with three non-zero homogeneous weights over $\mathbb{Z}_{p^m},$ for $p$ a prime, and more generally over chain rings of depth $m$, and with a residue field of size $q$, a prime power. Infinite families of examples are built from Kerdock and generalized Teichm\"uller codes. As a byproduct, we give an alternative proof that the Kerdock code is nonlinear.Comment: 28 pages, 6 table

Characterization of the composition and toxicity of particulate matter emissions from advanced heavy-duty natural gas engines

Heavy-duty natural gas engines compliant with the 2010 EPA emissions standards have a clear advantage over diesel engines in meeting regulations with minimal after-treatment configuration. Heavy-duty natural gas engines are largely promoted as a cleaner burning engine with respect to low PM mass emissions. However, lack of sufficient data and literature on the exhaust emissions from advanced natural gas engines and the potential adverse health effects has raised concern amongst regulatory agencies. Also, the ammonia emissions from three-way catalyst equipped heavy-duty natural gas engines could be a major contributor to the formation of secondary PM in the atmosphere.;This CARB funded study focuses primarily on characterizing the toxicity of the volatile fraction of PM from advanced heavy-duty natural gas engines. The objective of the study also includes characterizing the unregulated species of the exhaust together with number concentration and size distribution of ultrafine nanoparticle emissions. CNG fueled transit buses were tested on WVU\u27s heavy-duty chassis dynamometer in Stockton, CA. A wide array of sampling procedures was included to characterize the complete chemical composition of the exhaust. The toxicity analysis included three different assays a) DHBA b) DTT and c) alveolar macrophage ROS assay.;Results of the gas phase chemical speciation results reported all carbonyl, PAH and VOC emissions close to levels found in background or below the detection limits of the analytical method. Results of elemental analysis reported elements such as calcium, phosphorus, potassium, zinc, sulfur and magnesium are some of the metals that were found in significant concentration in the PM samples. The findings of the study directly relate lubrication oil as the single most dominant source to non-volatile fraction PM emissions in the tailpipe. Both DHBA and DTT assay correlated highly with mass of elements and metals such as zinc, iron and cobalt. The DTT assay resulted in high correlation with mass of copper, zinc, phosphorus and PAH with molecular weight less than 200. The findings of this study also reported the possible formation of non-volatile nucleation mode particles of 10 nm size range

Productivity prediction model based on Bayesian analysis and productivity console

Software project management is one of the most critical activities in modern software development projects. Without realistic and objective management, the software development process cannot be managed in an effective way. There are three general problems in project management: effort estimation is not accurate, actual status is difficult to understand, and projects are often geographically dispersed. Estimating software development effort is one of the most challenging problems in project management. Various attempts have been made to solve the problem; so far, however, it remains a complex problem. The error rate of a renowned effort estimation model can be higher than 30% of the actual productivity. Therefore, inaccurate estimation results in poor planning and defies effective control of time and budgets in project management. In this research, we have built a productivity prediction model which uses productivity data from an ongoing project to reevaluate the initial productivity estimate and provides managers a better productivity estimate for project management. The actual status of the software project is not easy to understand due to problems inherent in software project attributes. The project attributes are dispersed across the various CASE (Computer-Aided Software Engineering) tools and are difficult to measure because they are not hard material like building blocks. In this research, we have created a productivity console which incorporates an expert system to measure project attributes objectively and provides graphical charts to visualize project status. The productivity console uses project attributes gathered in KB (Knowledge Base) of PAMPA II (Project Attributes Monitoring and Prediction Associate) that works with CASE tools and collects project attributes from the databases of the tools. The productivity console and PAMPA II work on a network, so geographically dispersed projects can be managed via the Internet without difficulty

Prototyping Elliptically Profiled Inverted Pendulum Walls in Cross-laminated Timber (CLT) for Passive Self-centering and Seismic Resiliency

Cross-laminated timber (CLT) buildings garnered international attention, nearly a decade ago, for elevating wood construction to new heights on fully panelized assemblies of floors and walls. While highly regarded as a sustainable building material, use of CLT as a structural wall system depends on seismically resilient strategies like controlled rocking. This project prototyped elliptically profiled CLT panels and slotted-pin steel connections, at full-scale, to produce rolling and slip-friction inverted pendulum wall systems of one-story height and inspired by seismic isolation concepts. Digital fabrication realized elliptical profiles along the load-bearing edges of six 5-ply CLT panels and various customized slot shapes for accompanying steel connections. Pins traveling within V-shaped slots intended only to guide rolling as displacement restraints, in contrast with pins constrained within vertical slots that forced panels into slip-friction combinations of rolling and sliding. Six CLT panels and two versions of shear transfer connections yielded a total of 12 full-scale wall prototype configurations for cyclic lateral load-displacement testing that emulated standard quasi-static protocols for seismic isolation. The hysteresis plots generated by the tests confirmed that elliptical eccentricity predictably controlled effective lateral stiffness and displacement capacity, while providing inherent self-centering. When configured to roll using traction along steel bearing surfaces as the primary mechanism of story shear transfer, CLT panels supported simulated gravity loads as high as 400 kN (90 kips) while achieving story drifts commonly exceeding 10 and even 20 percent. When configured to transfer shear primarily through a pin connection, however, CLT panels slid and sustained damage that limited gravity load capacity to 133 kN (30 kips). Connection constraint, therefore, dictated whether friction essentially transferred story shears transfer or dissipated energy. To help explain implications of friction, Digital Image Correlation (DIC), piezoelectric film pressure mapping, Finite Element Analysis, and fundamental free-body diagrams visualized the behavior of high-pressure contact between timber and steel. Despite the low damping exhibited by rolling and increased damage of slip-friction rocking, both models of elliptically profiled rocking walls can develop into viable options for isolation planes within multistory building schemes, based on the results of this study