NFPA Fluid Powered Vehicle Challenge 2023

This report includes the design process undergone by Team Shifty in designing a vehicle for the NFPA’s Fluid Powered Vehicle challenge. The report covers the background of the competition, research done by the team, engineering specifications for the design, preliminary and final designs, the manufacturing plan and process, project management details, and several recommendations for future teams participating in the challenge. The National Fluid Power Association, NFPA, is a trade association with the goal of connecting fluid power companies and advancing fluid power. With the goal of advancement in mind, NFPA hosts an annual Fluid Powered Vehicle Challenge (FPVC). Since before the NFPA took over this challenge, Cal Poly has produced a team to compete. Team Shifty completed research into past Cal Poly teams as well as other competing university teams to define the engineering specifications for the new vehicle and decide the design directions. The final design includes a new frame to address issues with the last teams frame, a new hydraulic circuit design and selection of new components to improve the circuits performance in the FPVC events and reduce losses, and the addition of gear shifting to the vehicle. With respect to hydraulics, a new manifold was sourced to accommodate the simplified fluid circuit, along with a larger motor to allow the vehicle to operate at higher torque. The prior team’s pneumatic system was completely replaced by a pneumatic front gear shifting system. The electronics implemented was the same system as the previous year, including an STM microcontroller, Nextion touch screen display, and Hydraforce valve operator with only two solenoid valves. Working together, these components allowed the rider to toggle between three unique drive modes, including: direct, regen, and sprint. To produce a functional vehicle, research and planning was put into manufacturing and assembly processes as detailed in the manufacturing plan. The final product failed to perform as proposed in Team Shifty’s Scope of Work, as the vehicle’s rear chain consistently fell off during operation at the competition. This resulted in the vehicle not placing during a few of the challenges, including the Sprint and Endurance races. The cause of this failure was a function of the frame flexing under dynamic loading due to insufficient torsional stiffness, as well as the rear chain being too small to handle the large output torque of the upsized rear motor

Complexity of decision problems for simple regular expressions

We study the complexity of the inclusion, equivalence, and intersection problem for simple regular expressions arising in practical XML schemas. These basically consist of the concatenation of factors where each factor is a disjunction of strings possibly extended with ‘∗ ’ or ‘?’. We obtain lower and upper bounds for various fragments of simple regular expressions. Although we show that inclusion and intersection are already intractable for very weak expressions, we also identify some tractable cases. For equivalence, we only prove an initial tractability result leaving the complexity of more general cases open. The main motivation for this research comes from database theory, or more specifically XML and semi-structured data. We namely show that all lower and upper bounds for inclusion and equivalence, carry over to the corresponding decision problems for extended context-free grammars and single-type tree grammars, which are abstractions of DTDs and XML Schemas, respectively. For intersection, we show that the complexity only carries over for DTDs

Efficient schema-based revalidation of XML

Abstract. As XML schemas evolve over time or as applications are integrated, it is sometimes necessary to validate an XML document known to conform to one schema with respect to another schema. More generally, XML documents known to conform to a schema may be modified, and then, require validation with respect to another schema. Recently, solutions have been proposed for incremental validation of XML documents. These solutions assume that the initial schema to which a document conforms and the final schema with which it must be validated after modifications are the same. Moreover, they assume that the input document may be preprocessed, which in certain situations, may be computationally and memory intensive. In this paper, we describe how knowledge of conformance to an XML Schema (or DTD) may be used to determine conformance to another XML Schema (or DTD) efficiently. We examine both the situation where an XML document is modified before it is to be revalidated and the situation where it is unmodified.

A comparative evaluation of heuristic-based usability inspection methods

Given that heuristic evaluation (HE) is a popular evaluation method among practitioners despite criticisms surrounding its performance and reliability, there is a need to improve the method's performance. Several studies have shown HE-Plus, an emerging variant of HE, to outperform HE in both effectiveness and reliability. HE-Plus uses the same set of heuristics as HE; the only difference between these two methods is the 'usability problems profile' element in HE-Plus. This paper reports our attempt to verify the original profile employed in HE-Plus based on usability problem classification in the User Action Framework and an experiment evaluating its outcome by comparing HE with two HE variants using a profile (HE-Plus and HE++) and a control group. Our results confirmed the role of the 'usability problems profiles' on improving the performance and reliability of heuristic evaluation: both HE-Plus and HE++ outperformed HE in terms of effectiveness as well as reliability

Abseq: Ultrahigh-throughput single cell protein profiling with droplet microfluidic barcoding

Proteins are the primary effectors of cellular function, including cellular metabolism, structural dynamics, and information processing. However, quantitative characterization of proteins at the single-cell level is challenging due to the tiny amount of protein available. Here, we present Abseq, a method to detect and quantitate proteins in single cells at ultrahigh throughput. Like flow and mass cytometry, Abseq uses specific antibodies to detect epitopes of interest; however, unlike these methods, antibodies are labeled with sequence tags that can be read out with microfluidic barcoding and DNA sequencing. We demonstrate this novel approach by characterizing surface proteins of different cell types at the single-cell level and distinguishing between the cells by their protein expression profiles. DNA-tagged antibodies provide multiple advantages for profiling proteins in single cells, including the ability to amplify low-abundance tags to make them detectable with sequencing, to use molecular indices for quantitative results, and essentially limitless multiplexing

Conditional and specific NF-κB blockade protects pancreatic beta cells from diabetogenic agents

Type 1 diabetes is characterized by the infiltration of inflammatory cells into pancreatic islets of Langerhans, followed by the selective and progressive destruction of insulin-secreting beta cells. Islet-infiltrating leukocytes secrete cytokines such as IL-1β and IFN-γ, which contribute to beta cell death. In vitro evidence suggests that cytokine-induced activation of the transcription factor NF-κB is an important component of the signal triggering beta cell apoptosis. To study the in vivo role of NF-κB in beta cell death, we generated a transgenic mouse line expressing a degradation-resistant NF-κB protein inhibitor (ΔNIκBα), acting specifically in beta cells, in an inducible and reversible manner, by using the tet-on regulation system. In vitro, islets expressing the ΔNIκBα protein were resistant to the deleterious effects of IL-1β and IFN-γ, as assessed by reduced NO production and beta-cell apoptosis. This effect was even more striking in vivo, where nearly complete protection against multiple low-dose streptozocin-induced diabetes was observed, with reduced intraislet lymphocytic infiltration. Our results show in vivo that beta cell-specific activation of NF-κB is a key event in the progressive loss of beta cells in diabetes. Inhibition of this process could be a potential effective strategy for beta-cell protection

Foundations of XML based on Logic and Automata: a snapshot

XML query and schema languages have some obvious connection