Search results for "General Computer Science"
showing 10 items of 895 documents
State of the Art in Information Security Policy Development
2020
Despite the prevalence of research that exists under the label of “information security policies” (ISPs), there is no consensus on what an ISP means or how ISPs should be developed. This article reviews state-of-the-art ISP development by examining a diverse sample of literature on the subject. The definition and function of an ISP is studied first, revealing a rich tapestry of different notions behind the same term. When looking at the broad picture of the research on ISP development methods, we find different phases and levels of detail. Analyzing the different views on the content, context, and strategy alignment provides for further understanding on the complexity of the matter. As an o…
Content quality assessment and acceptance testing in location‐based services
2006
In this paper, we develop and evaluate an approach to assessing the content quality in a location‐based service (LBS). The proposed approach, instead of assessing the quality in absolute terms such as completeness or accuracy, measures the effect that the imperfection of the content is having on the reliability of that specific LBS. We apply the basic ideas from Software Reliability Engineering (SRE), but develop a modification of SRE, 2‐Branch, in order to separate content quality from other factors, such as positioning imprecision, and to reduce the measurement error. In our experimental study, we first compare 2‐Branch to the standard SRE, after which we experimentally analyze some prope…
Online assessment of strategic reading literacy skills
2015
This study investigates the possibility of assessing strategic reading literacy skills with computers. The critical value of this assessment is the recording of online indices of the reader's behavior that can be interpreted in terms of strategies. The study uses materials of a standardized paper-and-pencil reading literacy test called CompLEC (Llorens et?al., 2011) and a technology called Read&Answer (Vidal-Abarca et?al., 2011) that presents texts and questions with a masking procedure that allows the recording of reading time and readers' actions to develop a computer-based version called e-CompLEC. We found that reliability and validity of the two versions are largely equivalent, and tha…
A framework for behavior-based detection of user substitution in a mobile context
2007
Personal mobile devices, such as mobile phones, smartphones, and communicators can be easily lost or stolen. Due to the functional abilities of these devices, their use by unintended persons may result in severe security breaches concerning private or corporate data and services. Organizations develop their security policy and employ preventive techniques to combat unauthorized use. Current solutions, however, are still breakable and there is a strong need for means to detect user substitution when it happens. A crucial issue in designing such means is to define the measures to be monitored. In this paper, a structured conceptual framework for mobile-user substitution detection is proposed.…
Assessing the Performance of Interactive Multiobjective Optimization Methods
2021
Interactive methods are useful decision-making tools for multiobjective optimization problems, because they allow a decision-maker to provide her/his preference information iteratively in a comfortable way at the same time as (s)he learns about all different aspects of the problem. A wide variety of interactive methods is nowadays available, and they differ from each other in both technical aspects and type of preference information employed. Therefore, assessing the performance of interactive methods can help users to choose the most appropriate one for a given problem. This is a challenging task, which has been tackled from different perspectives in the published literature. We present a …
The potential of temporal analysis: Combining log data and lag sequential analysis to investigate temporal differences between scaffolded and non-sca…
2020
This paper contributes to the ongoing discussion about analysing the temporal aspects of learning processes in the educational technology research field. Our main aim was to advance methods for analysing temporal aspects of technology-enhanced learning (TEL) processes by introducing the temporal lag sequential analysis (TLSA) technique and by combining TLSA with temporal log data analysis (TLDA). Our secondary aim was to illustrate the potential of these two analysis techniques to reveal the differences between the face-to-face technology-enhanced collaborative inquiry-based learning (CIBL) processes of three different conditions (non-scaffolded, writing scaffolded and script scaffolded gro…
Computer modelling of point defects in ABO3 perovskites and MgO
2004
We present results for basic intrinsic defects: F-type electron centers (O vacancy which trapped one or two electrons) and hole polarons bound to Mg or K vacancy in ionic MgO and partly covalent KNbO3 perovskite, respectively. We demonstrate that a considerable covalency of the perovskite chemical bonding makes the F-type centers therein much more similar to defects in partly-covalent quartz-type oxides rather than the conventional F centers in alkali halides and ionic MgO. Both one-site (atomic) and two-site (molecular) polarons are expected to coexist in KNbO3 characterized by close absorption energies. Our calculations confirm existence of the self-trapped electron polarons in KNbO3, KTa…
A comparative study of the atomic and electronic structure of F centers in ferroelectric KNbO3: Ab initio and semi-empirical calculations
1998
Abstract The linear muffin-tin-orbital method combined with density functional theory (in a local density approximation) and the semi-empirical method of the intermediate neglect of the differential overlap (INDO) based on the Hartree-Fock formalism are used for the supercell study of the F centers (O vacancy with two electrons) in cubic and orthorhombic ferroelectric KNbO3 crystals. The two electrons are found to be considerably delocalized even in the ground state of the defect. Their wave functions extend over the two Nb atoms closest to the O vacancy and over other nearby atoms. Thus, the F center in KNbO3 resembles much more electron defects in the partly covalent SiO2 crystal (the so-…
Atomic and electronic structure of perfect and defective PbZrO3 perovskite: Hybrid DFT calculations of cubic and orthorhombic phases
2007
Abstract The structural and electronic properties of pure cubic and low-temperature orthorhombic PbZrO3 (antiferroelectric phase), as well as cubic PbZrO3 containing single F-centers (neutral oxygen vacancies) have been simulated by means of ab initio hybrid density functional calculations. We observed a substantial increase of the Pb–O bond covalency in ideal orthorhombic PbZrO3 with respect to its cubic phase. Relatively large displacement of four Pb atoms nearest to the F-center (0.25 A towards the defect) could affect the PbZrO3 ferroelectric properties. An O vacancy in the bulk PbZrO3 attracts ≈0.7 e, and the remaining electron density from the missing O2− is localized mostly on four n…
HyperLabelMe : A Web Platform for Benchmarking Remote-Sensing Image Classifiers
2017
HyperLabelMe is a web platform that allows the automatic benchmarking of remote-sensing image classifiers. To demonstrate this platform's attributes, we collected and harmonized a large data set of labeled multispectral and hyperspectral images with different numbers of classes, dimensionality, noise sources, and levels. The registered user can download training data pairs (spectra and land cover/use labels) and submit the predictions for unseen testing spectra. The system then evaluates the accuracy and robustness of the classifier, and it reports different scores as well as a ranked list of the best methods and users. The system is modular, scalable, and ever-growing in data sets and clas…