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Search Results: 1 - 10 of 718 matches for " Anastasia Lavrenko "
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Cognitive Scout Node for Communication in Disaster Scenarios
Rajesh K. Sharma,Anastasia Lavrenko,Dirk Kolb,Reiner S. Thom?
Journal of Computer Networks and Communications , 2012, DOI: 10.1155/2012/160327
Abstract: The cognitive radio (CR) concept has appeared as a promising technology to cope with the spectrum scarcity caused by increased spectrum demand due to the emergence of new applications. CR can be an appropriate mean to establish self-organization and situation awareness at the radio interface, which is highly desired to manage unexpected situations that may happen in a disaster scenario. The scout node proposed in this paper is an extended concept based on a powerful CR node in a heterogeneous nodes environment which takes a leading role for highly flexible, fast, and robust establishment of cooperative wireless links in a disaster situation. This node should have two components: one is a passive sensor unit that collects and stores the technical knowledge about the electromagnetic environment in a data processing unit so-called “radio environment map” in the form of a dynamically updated database, and other is an active transceiver unit which can automatically be configured either as a secondary node for opportunistic communication or as a cooperative base station or access point for primary network in emergency communications. Scout solution can be viable by taking advantage of the technologies used by existing radio surveillance systems in the context of CR. 1. Introduction Communication has been an indispensable part of everyday life in the present days. Apart from making the general life better, modern communications should also be applicable for relief and support to the victims of exceptional adverse situations which include disaster scenarios like earthquakes, floods, cyclones, forest fires and terrorist attacks. Such scenarios impose new requirements on the communication systems. Some of the tasks of a cognitive radio network for emergency situations may be (1) to support specific service requests (higher traffic, coverage, localization, emergency messages, etc.), (2) to re-establish communications in a short time, and (3) to assist rescue forces communications and provide interoperability among them and also among rescue forces and public network. One of the first tasks in disaster is to organize rescue operations in a quick and efficient manner which as well requires rescue forces to be provided with reliable and stable communication facilities. One of the common problems here is providing interoperability among rescue responders originally using different communication standards [1, 2]. In terms of public communication systems, obvious problems in such scenarios are capacity overload with the resulting service denial and absence of coverage
Letter to Editor  [PDF]
Anastasia Maggina
Open Journal of Accounting (OJAcct) , 2013, DOI: 10.4236/ojacct.2013.24013
Abstract: Letter to Editor
The Social Framework of Learning via Neurodidactics  [PDF]
Chournazidi Anastasia
Creative Education (CE) , 2016, DOI: 10.4236/ce.2016.715215
Abstract: Both from a pedagogical and a psychological point of view, but also from sociology, we are aware of the fact that learning is a permanently successful process, taking into consideration that learning in the school environment does not bear significant practical differences from learning in our normal, social lives. Since the 18th century already, educational theories have been developed, accepting teaching methods focusing on learning processes, in accordance with human’s brain functions and aiming not for an individual, but a social aspect of learning, enhancing the individual’s self- efficacy in society. Neurodidactics investigates these two parameters, in an effort to introduce brain research scientific results into courses, forging at the same time the frameworks and prerequisites used to establish knowledge that was correctly structured and integrated in a context of emotional motivation. The neurodidactics’ aim is to encourage and support the management and process of learning, in a stress-free, reliable, social learning context. The following analysis of these theories should assist teachers in understanding and explaining their students’ experiences and behaviors, which should always be related to the students’ brain functions and physical-mental functions, as part of a learning group.
I Wish I Didn't Say That! Analyzing and Predicting Deleted Messages in Twitter
Sasa Petrovic,Miles Osborne,Victor Lavrenko
Computer Science , 2013,
Abstract: Twitter has become a major source of data for social media researchers. One important aspect of Twitter not previously considered are {\em deletions} -- removal of tweets from the stream. Deletions can be due to a multitude of reasons such as privacy concerns, rashness or attempts to undo public statements. We show how deletions can be automatically predicted ahead of time and analyse which tweets are likely to be deleted and how.
The Body Mass Index (BMI) and TV Viewing in a Co-Integration Framework  [PDF]
Anastasia Victoria Lazaridi
Sociology Mind (SM) , 2012, DOI: 10.4236/sm.2012.23037
Abstract: Many techniques are met in the literature, trying to investigate the effect of TV watching hours on BMI. However, we haven’t traced any empirical study with co-integration analysis, as it is applied here. With this in mind, we present in this paper the proper methodology, based on the co-integration analysis for a detailed justification of the effect of TV viewing hours together with some minor changes in life style of participants on BMI. Apart from finding and testing an acceptable co-integration relation, we further formulated an error correction model to determine the coefficient of adjustment. All findings, which are fully justified, are presented in details in the relevant sections. It should be pointed out, that we haven’t met this type of analysis in the relevant literature.
Simulation of Olive Kernel Gasification in a Bubbling Fluidized Bed Pilot Scale Reactor  [PDF]
Stavros Michailos, Anastasia Zabaniotou
Journal of Sustainable Bioenergy Systems (JSBS) , 2012, DOI: 10.4236/jsbs.2012.24021
Abstract:

The main aim of this study is to develop a comprehensive process model for biomass gasification in a pilot scale bubbling fluidized bed gasifier using the ASPEN PLUS simulator. A drawback in using ASPEN PLUS is the lack of a library model to simulate fluidized bed unit operation. However, it is possible for users to input their own models, using FORTRAN codes nested within the ASPEN PLUS input file, to simulate operation of a fluidized bed. The products of homogeneous reactions are defined by Gibbs equilibrium and reaction rate kinetics are used to determine the products of char gasification. Governing hydrodynamic equations for a bubbling bed and kinetic expressions for the char combustion were adopted from the literature. Different sets of gasification results for the operation conditions (temperature and air equivalence ratio (ER)) obtained from the our pilot-scale gasifier having a capacity of 1 kg/hr of olive kernel as feeding biomass, were used to demonstrate the validation of the model. The simulation results received from the application of the model were compared with the above experimental results and showed good agreement.

A Comparative Analysis of Cognitive and Psychosocial Functioning in Children with Writing Disabilities  [PDF]
Anastasia Alevriadou, Stergiani Giaouri
Psychology (PSYCH) , 2016, DOI: 10.4236/psych.2016.72018
Abstract: The purpose of the study was to investigate the relationship between the Test of Detection and Investigation of Attention and Concentration, the Test of Executive Function (Simos et al., 2007a,b) and the Test of Psychosocial Adjustment and Self-Report Scale (Hatzichristou et al., 2007), in a sample of 44 Greek 5th grade students with writing disabilities. The results in our study indicated that there were significant Pearson correlations ranged from 0.39 to 0.43 between cognitive, academic and social factors. Additionally, regression analysis indicated that certain scales of the Test of Attention and Concentration have predictive power to emotional sufficiency (t = 2.001, p < 0.05) and academic self-concept (t = 2.072, p < 0.05). Further implications of these findings for a school-based neuropsychological evaluation and planning of individualized educational interventions are discussed.
A Class of Generalized Approximate Inverse Solvers for Unsymmetric Linear Systems of Irregular Structure Based on Adaptive Algorithmic Modelling for Solving Complex Computational Problems in Three Space Dimensions  [PDF]
Anastasia-Dimitra Lipitakis
Applied Mathematics (AM) , 2016, DOI: 10.4236/am.2016.711108
Abstract: A class of general inverse matrix techniques based on adaptive algorithmic modelling methodologies is derived yielding iterative methods for solving unsymmetric linear systems of irregular structure arising in complex computational problems in three space dimensions. The proposed class of approximate inverse is chosen as the basis to yield systems on which classic and preconditioned iterative methods are explicitly applied. Optimized versions of the proposed approximate inverse are presented using special storage (k-sweep) techniques leading to economical forms of the approximate inverses. Application of the adaptive algorithmic methodologies on a characteristic nonlinear boundary value problem is discussed and numerical results are given.
Teacher Emotions in Primary and Secondary Education: Effects of Self-Efficacy and Collective-Efficacy, and Problem-Solving Appraisal as a Moderating Mechanism  [PDF]
Georgia Stephanou, Anastasia Oikonomou
Psychology (PSYCH) , 2018, DOI: 10.4236/psych.2018.94053
Abstract: This study aimed to examine: 1) teachers’ self-reported emotions experienced at school, problem-solving appraisal, self-efficacy and school collective-efficacy; 2) the effects of self-efficacy on the formulation of collective-efficacy and problem-solving appraisal, and on the impact of problem-solving appraisal on collective-efficacy; 3) the influential role of efficacy beliefs, problem-solving appraisal and their inter-effects in the emotions; and 4) the effect of teaching level (primary/secondary school) in the examined concepts. The sample consists of 256 primary and secondary school teachers, 92 men and 164 women, who came from various Greek state schools. Data were collected at the middle of a school year, and they were analyzed between and within groups across all constructs. The results revealed: 1) teachers experienced positive emotions from moderate to high intensity, and negative emotions from low to high intensity, particularly context-, task- and self-related; 2) a moderate to high sense of both efficacy beliefs and problem-solving appraisal (except for personal control that was low); 3) while problem-solving appraisal influenced collective-efficacy, its effect was to a significant extent mediated by self-efficacy; 4) self-efficacy, problem-solving appraisal and collective-efficacy had complimentary impact on the emotions, with self-efficacy being the most powerful formulator of most of them; and 5) the primary school teachers, compared to secondary school teachers, felt more intense positive emotions, had a stronger sense of school collective-efficacy and reported lower impulsive and personal control in problem-solving. The findings are discussed with respect to their practical applications and future research.
Differentiated Instruction in Practice: Curriculum Adjustments in Kindergarten  [PDF]
Anastasia Mavidou, Domna Kakana
Creative Education (CE) , 2019, DOI: 10.4236/ce.2019.103039
Abstract: The present study aims to investigate the effectiveness of Differentiated Instruction (DI) on kindergarten children’s achievement. More specifically, the paper discusses the effect of different types of adjustments on an Integrated Curriculum following the DI approach. DI is a teaching and learning approach that provides a context to adjust sufficiently several aspects of the curriculum in order to address effectively the needs of all learners. However, the impact of DI is often related to several learning subjects, e.g. reading, mathematics etc., while scarce empirical evidence exists regarding its effectiveness in the context of an Integrated Curriculum. The majority of related research excludes the preschool education; hence,?more research about the appropriate implementation of DI in kindergarten settings is needed. The study was quasi-experimental, including pre- and post-tests to examine the effectiveness of DI in reaching the learning goals of three interventions. The participants were 80 kindergarteners for the experimental group and 74 children comprised the control group. The statistical analysis highlighted the positive impact of DI on their achievement. In addition, a tendency was found implying that differentiation by interests was the most effective type of adjustment. The results proved the applicability and positive impacts?of DI in kindergarten classrooms, while further research is needed to define and optimize the differentiation strategies and techniques.
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