Dimensional analysis is used to guide the experimental investigation and identify appropriate dimensionless groups. The scaling laws of the aerodynamic noise of the idling saw blades are established through evaluation...
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Dimensional analysis is used to guide the experimental investigation and identify appropriate dimensionless groups. The scaling laws of the aerodynamic noise of the idling saw blades are established through evaluation of the relationship between the dimensionless groups. Slotted disks (similar to saw blades) are used in the investigation. Effects of tip speed, thickness, gullet diameter, depth, and spacing on the noise produced are independently evaluated. Through the dimensional analysis, the secondary effects of the geometric parameters are isolated from the large-scale tip speed effect. Based on the experimental results, an empirical equation is developed to predict the levels radiated by the slotted disks. These results may be used to predict relative sound levels produced by saw blades as a function of geometric and kinematic variables. Using the parametric test results, conjectures are made as to the nature of the acoustic sources present in idling saw blades. The sources are believed to be combinations of acoustically compact monopoles arising from finite cross flow of the air in the gullets and compact dispoles produced at the lateral surface of the saw teeth due to the separated wake flow of the preceding saw teeth.
A natural way to interact with persons in Ambient Asssited Living (AAL) scenarios is through speech. Speech recognition techniques usually require of training for achieving good results. However, this training is not ...
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ISBN:
(纸本)9783642153839
A natural way to interact with persons in Ambient Asssited Living (AAL) scenarios is through speech. Speech recognition techniques usually require of training for achieving good results. However, this training is not possible when different people can enter and leave. In these scenarios, the system should get information from the context, such as the state of the environment or previous dialogues, to support the speech recognition process. This is made in this work with Talking Agents. These are autonomous entities, with the ability to interact with each other and with other agents in the environment, and with the responsibility of interacting with persons through speech. They have a modular architecture to facilitate the application of different mechanisms and strategies, depending on the concrete AAL scenario.
The propagation of high-frequency ultrasonic body waves can be efficiently estimated with a semi-analytic Dynamic Ray Tracing approach using paraxial approximation. Although this asymptotic field estimation avoids the...
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The propagation of high-frequency ultrasonic body waves can be efficiently estimated with a semi-analytic Dynamic Ray Tracing approach using paraxial approximation. Although this asymptotic field estimation avoids the computational cost of numerical methods, it may encounter several limitations in reproducing identified highly interferential features. Nevertheless, some can be managed by allowing paraxial quantities to be complex-valued. This gives rise to localized solutions, known as paraxial Gaussian beams. Whereas their propagation and transmission/reflection laws are well-defined, the fact remains that the adopted complexification introduces additional initial conditions. While their choice is usually performed according to strategies specifically tailored to limited applications, a Gabor frame method has been implemented to indiscriminately initialize a reasonable number of paraxial Gaussian beams. Since this method can be applied for an usefully wide range of ultrasonic transducers, the typical case of the time-harmonic piston radiator is investigated. Compared to the commonly used Multi-Gaussian Beam model [1], a better agreement is obtained throughout the radiated field between the results of numerical integration (or analytical on-axis solution) and the resulting Gaussian beam superposition. Sparsity of the proposed solution is also discussed.
This work deploys linguistically motivated features to classify paragraph-level text into fiction and non-fiction genre using a logistic regression model and infers lexical and syntactic properties that help distingui...
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Over the past several years, the building codes that govern commercial building construction have become increasingly prescriptive in nature, specifying detailed information related to the design and installation of t...
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We have developed software for creating databases of course materials on the World-Wide Web. The goal is to allow instructors at different institutions to share materials and develop them jointly. Our first two databa...
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We have developed software for creating databases of course materials on the World-Wide Web. The goal is to allow instructors at different institutions to share materials and develop them jointly. Our first two databases, in computer architecture and object technology, comprise thousands of problems and lectures downloaded (with permission) from course Websites around the world. The database is searchable by classification or fulltext string. To populate the databases with up-to-date material, we started by building a list of course Websites. Using several sources, we came up with a list of 73 sites in computer architecture and 40 sites in object technology. However, only a minority of authors gave us permission to load their material. To provide access to a larger amount of material, we are extending our search capability to include material on the Web as well as in the database. The search engine that we have used finds course Websites by searching a filtered set of educational domains for sites containing keywords characteristic of course material in the target discipline. Finally, we report on our experience of building software using a combination of funded research assistants, students working on senior-design projects, and independent-study students.
It's a big challenge for businesses to increase security in the age of digital technologies, especially for online shops. In online shopping, hackers can penetrate networks and steal private information about cust...
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Virtual and digital learning being the new normal, pandemic outburst and unexpected disruption in the functioning of educational services have paved way for online learning services. Considering the fast-track growth ...
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ISBN:
(纸本)9781665453622
Virtual and digital learning being the new normal, pandemic outburst and unexpected disruption in the functioning of educational services have paved way for online learning services. Considering the fast-track growth of the education technology (EdTech) industry, in order to sustain, it is imperative for the industry to understand the underlying issues by capturing the end users’ perception. The primary purpose of this research is to examine the perception of users towards EdTech platforms A sample of 600 reviews regarding three major EdTech platforms were scraped from *** as textual data and analysed using lexicon-based method. The polarity of the sentiments pertaining to the reviews of different platforms was analysed using sentiment analysis. Furthermore, the topic modelling on the reviews was performed using natural language programming. The results revealed a positive sentiment of users towards the EdTech services and platforms. The most influential factors are faculty expertise, interface user-friendliness, syllabus, and pricing model. Our findings help EdTech service providers to understand which factors are driving this dramatic shift in student behaviour so they may develop better strategies to attract and retain consumers. Despite the rise in EdTech platform popularity, this is the first study to investigate perception of EdTech users comprehensively.
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