Search results for "edge"
showing 10 items of 3866 documents
Ítems contextualizados de PISA Ciencias: La conexión entre las demandas cognitivas y las características de contexto de los ítems
2016
El uso frecuente de contextos en los ítems de la prueba se basa en la premisa de que la contextualización de ítems es una estrategia eficaz para comprobar si los estudiantes pueden aplicar o transferir sus conocimientos. En este trabajo, seguimos una línea de investigación que se centra en probar esta premisa. Se presenta un estudio de las características del contexto en una muestra de ítems de PISA ciencias de 2006 y 2009 y cómo estas características, así como el rendimiento del estudiante puede estar relacionado con las demandas cognitivas en los ítems. El estudio se basa en dos preguntas de investigación: (1) ¿Cuáles son las demandas cognitivas de los ítems contextualizados en la muestra…
The mapping properties of the radiosity operator along an edge
2002
In this article we study the radiosity operator along an edge between two adjacent half-planes. First we show that the radiosity operator is invertible in a whole scale of anisotropic Sobolev spaces. In the absence of any shadows we are able to derive regularity properties of the solution, which depend only on the angle between the half-planes, the reflectivity coefficients and the right-hand side. This work can be considered as a supplement to the article of Rathsfeld (Mathematical Methods in the Applied Sciences 1999; 22: 217–241). Copyright © 2002 John Wiley & Sons, Ltd.
In vitro perception of low-contrast features in digital, film, and digitized dental radiographs: A receiver operating characteristic analysis
2005
Objective To compare experimentally the image quality of charged-coupled device (CCD)-based digital, flatbed scanner digitized, and dental film radiographs. Study design High-contrast standardized radiographs of an aluminum step wedge containing boreholes were obtained on dental radiographic film (F) and a CCD receptor (D). Digitization (S) was done with a flatbed scanner. Each radiograph was separated into 23 single images, 18 of which showed a dark spot. Thirty observers indicated their confidence on the visibility of the spots for a receiver operating characteristic (ROC) analysis. Results Mean Az values (area beneath the ROC curves) differed significantly (P < .05), being highest for D …
A Knowledge-Based System for the Automatic Generation of Plant Shutdown and Startup Schedules
1988
Abstract When the shutdown of a plant, or part of it, has been decided as consequence of a major fault, the generation of a safe shutdown schedule may be, for large and complex plants, a very difficult and delicate task. The same problem may be found when the plant must be restarted after the fault has been repaired, for the generation of a start-up schedule. The use of a knowledge-based system appears to be a suitable answer to this problem, allowing a high level of safety and a very fast generation process. The paper examines the process knowledge that needs to be included in such a knowledge-based system and proposes some knowledge representation forms that appear suitable for the task t…
A Learning Automata Based Solution to Service Selection in Stochastic Environments
2010
Published version of a paper published in the book: Trends in Applied Intelligent Systems. Also available on SpringerLink: http://dx.doi.org/10.1007/978-3-642-13033-5_22 With the abundance of services available in today’s world, identifying those of high quality is becoming increasingly difficult. Reputation systems can offer generic recommendations by aggregating user provided opinions about service quality, however, are prone to ballot stuffing and badmouthing . In general, unfair ratings may degrade the trustworthiness of reputation systems, and changes in service quality over time render previous ratings unreliable. In this paper, we provide a novel solution to the above problems based …
Resource Allocation for Edge Computing-Based Blockchain: A Game Theoretic Approach
2020
Blockchain has been progressively applied to various Internet of Things (IoT) platforms. As the efficiency of the blockchain depends on its computing capability, how to make sure the acquisition of the computational resources and participation of the devices would be the driving force. In this work, an edge computing-based blockchain network is considered, where the edge service provider (ESP) offers computational resources for the miners. The focus is to investigate an efficient incentive mechanism for the miners to purchase the computational resources. Accordingly, a two-stage Stackelberg game is formulated between the miners and ESP. By exploring the Stackelberg equilibrium of the optima…
Analyzing the Contextual Nature of Collaborative Activity
2010
This chapter discusses a methodology designed to explore the contextual nature of collaborative activity. The methods that can be generally considered to be based on ‘socio-cultural’ discourse analysis are discussed as a means to explore how different aspects of a situation mediate students’ shared meaning-making. First, an analysis is demonstrated, illustrating how different immediate and mediated contexts are embedded in students’ discourse as they are engaged in face-to-face collaborative activity in a computer-mediated context. Second, a multidimensional coding scheme is presented for analyzing the contextualized process of collaborative knowledge construction in an asynchronous web-ba…
Solving Non-Stationary Bandit Problems by Random Sampling from Sibling Kalman Filters
2010
Published version of an article from Lecture Notes in Computer Science. Also available at SpringerLink: http://dx.doi.org/10.1007/978-3-642-13033-5_21 The multi-armed bandit problem is a classical optimization problem where an agent sequentially pulls one of multiple arms attached to a gambling machine, with each pull resulting in a random reward. The reward distributions are unknown, and thus, one must balance between exploiting existing knowledge about the arms, and obtaining new information. Dynamically changing (non-stationary) bandit problems are particularly challenging because each change of the reward distributions may progressively degrade the performance of any fixed strategy. Alt…
Life-based design as an extension of problem-based learning &#x2014; A tool for understanding people and technology
2015
Global conditions are changing at such a rate that foreseeing trends in technological development, economic fluctuations and climatic conditions is ever more difficult. When developing technologies, there is one constant factor that practitioners and researchers should be aware of, and that is people. This is not to say that people, culture and social conditions remain stagnant, for these too evolve with the surrounding circumstances. Rather, appropriate tools and capabilities for investigating people, their lives and life situations, are integral to understanding what people need in terms of technology, how these technologies will be used, and more importantly how they will be valued in th…
Contributions to the knowledge base on PV performance: Evaluation of the operation of PV systems using different technologies installed in southern N…
2011
To assist in establishing an accepted knowledge base on PV-modules and systems performance using a representative range of technologies, devices have to be installed at diverse locations, covering a broad range of environmental conditions. For the example of a high latitude location, modules and systems are installed and under investigation in southern Norway (Kristiansand region) by the University of Agder in cooperation with industrial partners. This paper presents first results of the analysis of module performance. The operational behavior of the modules is used to derive a modeling scheme applicable for performance prediction. This use is demonstrated by giving the expected annual perf…