2,904 research outputs found
The Rural Towns Program : groundwater modelling : the Merredin catchment
Agriculture Western Australia (Agwest), as part of the Rural Towns Program, was engaged to test the application of a groundwater model for potential future management options against salinity for the Merredin townsite. This report illustrates some of the options that could be implemented to achieve the objective of salinity management
An Energy-conscious Transport Protocol for Multi-hop Wireless Networks
We present a transport protocol whose goal is to reduce power consumption without compromising delivery requirements of applications. To meet its goal of energy efficiency, our transport protocol (1) contains mechanisms to balance end-to-end vs. local retransmissions; (2) minimizes acknowledgment traffic using receiver regulated rate-based flow control combined with selected acknowledgements and in-network caching of packets; and (3) aggressively seeks to avoid any congestion-based packet loss. Within a recently developed ultra low-power multi-hop wireless network system, extensive simulations and experimental results demonstrate that our transport protocol meets its goal of preserving the energy efficiency of the underlying network.Defense Advanced Research Projects Agency (NBCHC050053
Safe Compositional Specification of Networking Systems: A Compositional Analysis Approach
We present a type inference algorithm, in the style of compositional analysis, for the language TRAFFIC—a specification language for flow composition applications proposed in [2]—and prove that this algorithm is correct: the typings it infers are principal typings, and the typings agree with syntax-directed type checking on closed flow specifications. This algorithm is capable of verifying partial flow specifications, which is a significant improvement over syntax-directed type checking algorithm presented in [3]. We also show that this algorithm runs efficiently, i.e., in low-degree polynomial time.National Science Foundation (ITR ANI-0205294, ANI-0095988, ANI-9986397, EIA-0202067
An Advanced Engineering Framework experimented on a R&AE Electric Vehicle case
International audienceThis article describes modeling activity experimented on an Advanced engineering case of Zero Emission Vehicles at Renault. A key advantage of our approach is that system architecture and requirements management at all the stages of the system life cycle are managed in a unique data model and unique database. It reviews conceptualization and production process of a complex system. It presents a spectrum of activity modeling techniques, ranging from a widely used systems engineering diagram, to continuous flow modeling. The techniques include use case definition, requirements elicitation, system architecture definition and finally Electric and Electronic architecture. The article also describes refinements of modeling activity using arKItect© tool
A study of common aero-allergen in Mewar region, Udaipur, Rajasthan, India
Background: Aero-allergens are important causative factor in pathogenesis of allergic respiratory diseases (Asthma, Allergic Rhinitis). Present study aimed to identify the common aeroallergens in Mewar region, Udaipur, Rajasthan, India.Methods: Intradermal allergic testing done on 1050 respiratory allergic patients in last 15 yrs (2002 to 2016) by kit containing 125 allergen extracts includes pollen, fungi, insects, dust, dander’s, fabrics, feathers and wood. In 1020 patients (after excluding 30 patients), marked positive skin reaction (3+/4+) to one or more aeroallergen noted.Results: Most common aero allergens found were pollens (62%), woods (58.5%), dander (52%), insects (45%), dust mite (44.2%) and fungi (38.4%). Among pollens most common allergens were Holoptelia integrifolia, Parthenium hysterophorn, Cynodon. Among fungi aspergillus and candida species were most common. Cockroach and fly were predominant insects.Conclusions: Role of allergen testing have important role in management of allergic respiratory diseases as allergen immunotherapy or desensitization is only disease modifying treatment
Mathematical Models for Minimizing Total Tardiness on Parallel Additive Manufacturing Machines
In this research we tackle the scheduling problem in additive manufacturing for unrelated parallel machines. Both the nesting and scheduling aspects are considered. Parts have several alternative build orientations. The goal is to minimize the total tardiness of parts. We propose a mixed-integer linear programming model which considers the nesting subproblem as a 2D bin-packing problem, as well as a model which simplifies the nesting subproblem to a 1D bin-packing problem. The computational efficiency and properties of the proposed models are investigated by numerical experiments. Results show that the total tardiness optimization significantly increases the complexity of the problem, only the simple instances are solved optimally, whereas the makespan variant is able to solve all testing instances. Using the 1D bin-packing simplification allows for solving more instances to optimality, but with a risk of obtaining nesting-infeasibility. We also observed the compromise between the total tardiness and makespan objectives, which originates from the dilemma of “packing more parts to benefit from the common machine setup/recoating time” or “packing less parts to maintain the flexibility for handling distributed duedates”
Superlubricity mechanism of diamond-like carbon with glycerol. Coupling of experimental and simulation studies
We report a unique tribological system that produces superlubricity under boundary lubrication conditions with extremely little wear. This system is a thin coating of hydrogen-free amorphous Diamond-Like-Carbon (denoted as ta-C) at 353 K in a ta-C/ta-C friction pair lubricated with pure glycerol. To understand the mechanism of friction vanishing we performed ToF-SIMS experiments using deuterated glycerol and 13C glycerol. This was complemented by first-principles-based computer simulations using the ReaxFF reactive force field to create an atomistic model of ta-C. These simulations show that DLC with the experimental density of 3.24 g/cc leads to an atomistic structure consisting of a 3D percolating network of tetrahedral (sp3) carbons accounting for 71.5% of the total, in excellent agreement with the 70% deduced from our Auger spectroscopy and XANES experiments. The simulations show that the remaining carbons (with sp2 and sp1 character) attach in short chains of length 1 to 7. In sliding simulations including glycerol molecules, the surface atoms react readily to form a very smooth carbon surface containing OH-terminated groups. This agrees with our SIMS experiments. The simulations find that the OH atoms are mostly bound to surface sp1 atoms leading to very flexible elastic response to sliding. Both simulations and experiments suggest that the origin of the superlubricity arises from the formation of this OH-terminated surface
Process Mining for Dynamic Modeling of Smart Manufacturing Systems: Data Requirements
Modern manufacturing systems can benefit from the use of digital tools to support both short- and long-term decisions. Meanwhile, such systems reached a high level of complexity and are frequently subject to modifications that can quickly make the digital tools obsolete. In this context, the ability to dynamically generate models of production systems is essential to guarantee their exploitation on the shop-floors as decision-support systems. The literature offers approaches for generating digital models based on real-time data streams. These models can represent a system more precisely at any point in time, as they are continuously updated based on the data. However, most approaches consider only isolated aspects of systems (e.g., reliability models) and focus on a specific modeling purpose (e.g., material flow identification). The research challenge is therefore to develop a novel framework that systematically enables the combination of models extracted through different process mining algorithms. To tackle this challenge, it is critical to define the requirements that enable the emergence of automated modeling and simulation tasks. In this paper, we therefore derive and define data requirements for the models that need to be extracted. We include aspects such as the structure of the manufacturing system and the behavior of its machines. The paper aims at guiding practitioners in designing coherent data structures to enable the coupling of model generation techniques within the digital support system of manufacturing companies
Dissolution Potentials of Sodium & Potassium Chlorides, Bromides & Iodides & of Ammonium Halides
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