Turner, Raymond
2009-01-01
Computational models can be found everywhere in present day science and engineering. In providing a logical framework and foundation for the specification and design of specification languages, Raymond Turner uses this framework to introduce and study computable models. In doing so he presents the first systematic attempt to provide computational models with a logical foundation. Computable models have wide-ranging applications from programming language semantics and specification languages, through to knowledge representation languages and formalism for natural language semantics. They are al
Multidetector computed tomography of jaw lesions in children and adolescents
International Nuclear Information System (INIS)
Full text: Jaw lesions in paediatric and adolescent population are uncommon and can arise in odontogenic or non-odontogenic tissues. With the advent of multidetector computed tomography (MDCT), algorithm for imaging jaw lesions has changed dramatically. This pictorial essay describes the imaging appearance of commonly encountered jaw lesions in children and adolescents with emphasis on MDCT findings
Excessive recreational computer use and food consumption behaviour among adolescents.
L. Shi (Lu); Y. Mao (Yuping)
2010-01-01
textabstractINTRODUCTION: Using the 2005 California Health Interview Survey (CHIS) data, we explore the association between excessive recreational computer use and specific food consumption behavior among California's adolescents aged 12-17. METHOD: The adolescent component of CHIS 2005 measured the
Computational neurogenetic modeling
Benuskova, Lubica
2010-01-01
Computational Neurogenetic Modeling is a student text, introducing the scope and problems of a new scientific discipline - Computational Neurogenetic Modeling (CNGM). CNGM is concerned with the study and development of dynamic neuronal models for modeling brain functions with respect to genes and dynamic interactions between genes. These include neural network models and their integration with gene network models. This new area brings together knowledge from various scientific disciplines, such as computer and information science, neuroscience and cognitive science, genetics and molecular biol
Pediatric Computational Models
Soni, Bharat K.; Kim, Jong-Eun; Ito, Yasushi; Wagner, Christina D.; Yang, King-Hay
A computational model is a computer program that attempts to simulate a behavior of a complex system by solving mathematical equations associated with principles and laws of physics. Computational models can be used to predict the body's response to injury-producing conditions that cannot be simulated experimentally or measured in surrogate/animal experiments. Computational modeling also provides means by which valid experimental animal and cadaveric data can be extrapolated to a living person. Widely used computational models for injury biomechanics include multibody dynamics and finite element (FE) models. Both multibody and FE methods have been used extensively to study adult impact biomechanics in the past couple of decades.
The Computational Development of Reinforcement Learning during Adolescence
Palminteri, S., Khamassi, M., Joffily, M., Coricelli, G.; Kilford, E. J.; Coricelli, G.; Blakemore, S J
2016-01-01
Adolescence is a period of life characterised by changes in learning and decision-making. Learning and decision-making do not rely on a unitary system, but instead require the coordination of different cognitive processes that can be mathematically formalised as dissociable computational modules. Here, we aimed to trace the developmental time-course of the computational modules responsible for learning from reward or punishment, and learning from counterfactual feedback. Adolescents and adult...
The Computational Development of Reinforcement Learning during Adolescence.
Stefano Palminteri; Emma J. Kilford; Giorgio Coricelli; Sarah-Jayne Blakemore
2016-01-01
Adolescence is a period of life characterised by changes in learning and decision-making. Learning and decision-making do not rely on a unitary system, but instead require the coordination of different cognitive processes that can be mathematically formalised as dissociable computational modules. Here, we aimed to trace the developmental time-course of the computational modules responsible for learning from reward or punishment, and learning from counterfactual feedback. Adolescents and adult...
Excessive recreational computer use and food consumption behaviour among adolescents
Mao Yuping; Shi Lu
2010-01-01
Abstract Introduction Using the 2005 California Health Interview Survey (CHIS) data, we explore the association between excessive recreational computer use and specific food consumption behavior among California's adolescents aged 12-17. Method The adolescent component of CHIS 2005 measured the respondents' average number of hours spent on viewing TV on a weekday, the average number of hours spent on viewing TV on a weekend day, the average number of hours spent on playing with a computer on ...
Variables of excessive computer internet use in childhood and adolescence
Thalemann, Ralf
2010-01-01
The aim of this doctoral thesis is the characterization of excessive computer and video gaming in terms of a behavioral addiction. Therefore, the development of a diagnostic psychometric instrument was central to differentiate between normal and pathological computer gaming in adolescence. In study 1, 323 children were asked about their video game playing behavior to assess the prevalence of pathological computer gaming. Data suggest that excessive computer and video game players use thei...
The Computational Development of Reinforcement Learning during Adolescence.
Palminteri, Stefano; Kilford, Emma J; Coricelli, Giorgio; Blakemore, Sarah-Jayne
2016-06-01
Adolescence is a period of life characterised by changes in learning and decision-making. Learning and decision-making do not rely on a unitary system, but instead require the coordination of different cognitive processes that can be mathematically formalised as dissociable computational modules. Here, we aimed to trace the developmental time-course of the computational modules responsible for learning from reward or punishment, and learning from counterfactual feedback. Adolescents and adults carried out a novel reinforcement learning paradigm in which participants learned the association between cues and probabilistic outcomes, where the outcomes differed in valence (reward versus punishment) and feedback was either partial or complete (either the outcome of the chosen option only, or the outcomes of both the chosen and unchosen option, were displayed). Computational strategies changed during development: whereas adolescents' behaviour was better explained by a basic reinforcement learning algorithm, adults' behaviour integrated increasingly complex computational features, namely a counterfactual learning module (enabling enhanced performance in the presence of complete feedback) and a value contextualisation module (enabling symmetrical reward and punishment learning). Unlike adults, adolescent performance did not benefit from counterfactual (complete) feedback. In addition, while adults learned symmetrically from both reward and punishment, adolescents learned from reward but were less likely to learn from punishment. This tendency to rely on rewards and not to consider alternative consequences of actions might contribute to our understanding of decision-making in adolescence. PMID:27322574
The Computational Development of Reinforcement Learning during Adolescence.
Directory of Open Access Journals (Sweden)
Stefano Palminteri
2016-06-01
Full Text Available Adolescence is a period of life characterised by changes in learning and decision-making. Learning and decision-making do not rely on a unitary system, but instead require the coordination of different cognitive processes that can be mathematically formalised as dissociable computational modules. Here, we aimed to trace the developmental time-course of the computational modules responsible for learning from reward or punishment, and learning from counterfactual feedback. Adolescents and adults carried out a novel reinforcement learning paradigm in which participants learned the association between cues and probabilistic outcomes, where the outcomes differed in valence (reward versus punishment and feedback was either partial or complete (either the outcome of the chosen option only, or the outcomes of both the chosen and unchosen option, were displayed. Computational strategies changed during development: whereas adolescents' behaviour was better explained by a basic reinforcement learning algorithm, adults' behaviour integrated increasingly complex computational features, namely a counterfactual learning module (enabling enhanced performance in the presence of complete feedback and a value contextualisation module (enabling symmetrical reward and punishment learning. Unlike adults, adolescent performance did not benefit from counterfactual (complete feedback. In addition, while adults learned symmetrically from both reward and punishment, adolescents learned from reward but were less likely to learn from punishment. This tendency to rely on rewards and not to consider alternative consequences of actions might contribute to our understanding of decision-making in adolescence.
Institute of Scientific and Technical Information of China (English)
CHEN Shuyi; WEN Yingyou; ZHAO Hong
2006-01-01
In this paper, a formal approach based on predicate logic is proposed for representing and reasoning of trusted computing models. Predicates are defined to represent the characteristics of the objects and the relationship among these objects in a trusted system according to trusted computing specifications. Inference rules of trusted relation are given too. With the semantics proposed, some trusted computing models are formalized and verified, which shows that Predicate calculus logic provides a general and effective method for modeling and reasoning trusted computing systems.
The Computational Development of Reinforcement Learning during Adolescence
Palminteri, Stefano; Coricelli, Giorgio; Blakemore, Sarah-Jayne
2016-01-01
Adolescence is a period of life characterised by changes in learning and decision-making. Learning and decision-making do not rely on a unitary system, but instead require the coordination of different cognitive processes that can be mathematically formalised as dissociable computational modules. Here, we aimed to trace the developmental time-course of the computational modules responsible for learning from reward or punishment, and learning from counterfactual feedback. Adolescents and adults carried out a novel reinforcement learning paradigm in which participants learned the association between cues and probabilistic outcomes, where the outcomes differed in valence (reward versus punishment) and feedback was either partial or complete (either the outcome of the chosen option only, or the outcomes of both the chosen and unchosen option, were displayed). Computational strategies changed during development: whereas adolescents’ behaviour was better explained by a basic reinforcement learning algorithm, adults’ behaviour integrated increasingly complex computational features, namely a counterfactual learning module (enabling enhanced performance in the presence of complete feedback) and a value contextualisation module (enabling symmetrical reward and punishment learning). Unlike adults, adolescent performance did not benefit from counterfactual (complete) feedback. In addition, while adults learned symmetrically from both reward and punishment, adolescents learned from reward but were less likely to learn from punishment. This tendency to rely on rewards and not to consider alternative consequences of actions might contribute to our understanding of decision-making in adolescence. PMID:27322574
Computer Modeling and Simulation
Energy Technology Data Exchange (ETDEWEB)
Pronskikh, V. S. [Fermilab
2014-05-09
Verification and validation of computer codes and models used in simulation are two aspects of the scientific practice of high importance and have recently been discussed by philosophers of science. While verification is predominantly associated with the correctness of the way a model is represented by a computer code or algorithm, validation more often refers to model’s relation to the real world and its intended use. It has been argued that because complex simulations are generally not transparent to a practitioner, the Duhem problem can arise for verification and validation due to their entanglement; such an entanglement makes it impossible to distinguish whether a coding error or model’s general inadequacy to its target should be blamed in the case of the model failure. I argue that in order to disentangle verification and validation, a clear distinction between computer modeling (construction of mathematical computer models of elementary processes) and simulation (construction of models of composite objects and processes by means of numerical experimenting with them) needs to be made. Holding on to that distinction, I propose to relate verification (based on theoretical strategies such as inferences) to modeling and validation, which shares the common epistemology with experimentation, to simulation. To explain reasons of their intermittent entanglement I propose a weberian ideal-typical model of modeling and simulation as roles in practice. I suggest an approach to alleviate the Duhem problem for verification and validation generally applicable in practice and based on differences in epistemic strategies and scopes
Typologies of Computation and Computational Models
Burgin, Mark; Dodig-Crnkovic, Gordana
2013-01-01
We need much better understanding of information processing and computation as its primary form. Future progress of new computational devices capable of dealing with problems of big data, internet of things, semantic web, cognitive robotics and neuroinformatics depends on the adequate models of computation. In this article we first present the current state of the art through systematization of existing models and mechanisms, and outline basic structural framework of computation. We argue tha...
Computational Intelligence, Cyber Security and Computational Models
Anitha, R; Lekshmi, R; Kumar, M; Bonato, Anthony; Graña, Manuel
2014-01-01
This book contains cutting-edge research material presented by researchers, engineers, developers, and practitioners from academia and industry at the International Conference on Computational Intelligence, Cyber Security and Computational Models (ICC3) organized by PSG College of Technology, Coimbatore, India during December 19–21, 2013. The materials in the book include theory and applications for design, analysis, and modeling of computational intelligence and security. The book will be useful material for students, researchers, professionals, and academicians. It will help in understanding current research trends and findings and future scope of research in computational intelligence, cyber security, and computational models.
Grandi, Claudio; Colling, D; Fisk, I; Girone, M
2014-01-01
The CMS Computing Model was developed and documented in 2004. Since then the model has evolved to be more flexible and to take advantage of new techniques, but many of the original concepts remain and are in active use. In this presentation we will discuss the changes planned for the restart of the LHC program in 2015. We will discuss the changes planning in the use and definition of the computing tiers, that were defined with the MONARC project. We will present how we intend to use new services and infrastructure to provide more efficient and transparent access to the data. We will discuss the computing plans to make better use of the computing capacity by scheduling more of the processor nodes, making better use of the disk storage, and more intelligent use of the networking.
Adolescent Victims of Abuse: A Treatment Model.
Anderson-Merchant, Darlene
This paper presents a theory and model for treating adolescent victims of physical and sexual abuse and neglect. The theory examines issues related to abuse or neglect and the effect that an abusive history has on adolescent development. Specific issues noted are depression, anger, low self-esteem, self-shame, lack of trust, a sense of…
Understanding Student Computational Thinking with Computational Modeling
Aiken, John M; Douglas, Scott S; Burk, John B; Scanlon, Erin M; Thoms, Brian D; Schatz, Michael F
2012-01-01
Recently, the National Research Council's framework for next generation science standards highlighted "computational thinking" as one of its "fundamental practices". Students taking a physics course that employed the Arizona State University's Modeling Instruction curriculum were taught to construct computational models of physical systems. Student computational thinking was assessed using a proctored programming assignment, written essay, and a series of think-aloud interviews, where the students produced and discussed a computational model of a baseball in motion via a high-level programming environment (VPython). Roughly a third of the students in the study were successful in completing the programming assignment. Student success on this assessment was tied to how students synthesized their knowledge of physics and computation. On the essay and interview assessments, students displayed unique views of the relationship between force and motion; those who spoke of this relationship in causal (rather than obs...
Understanding student computational thinking with computational modeling
Aiken, John M.; Caballero, Marcos D.; Douglas, Scott S.; Burk, John B.; Scanlon, Erin M.; Thoms, Brian D.; Schatz, Michael F.
2013-01-01
Recently, the National Research Council's framework for next generation science standards highlighted "computational thinking" as one of its "fundamental practices". 9th Grade students taking a physics course that employed the Arizona State University's Modeling Instruction curriculum were taught to construct computational models of physical systems. Student computational thinking was assessed using a proctored programming assignment, written essay, and a series of think-aloud interviews, where the students produced and discussed a computational model of a baseball in motion via a high-level programming environment (VPython). Roughly a third of the students in the study were successful in completing the programming assignment. Student success on this assessment was tied to how students synthesized their knowledge of physics and computation. On the essay and interview assessments, students displayed unique views of the relationship between force and motion; those who spoke of this relationship in causal (rather than observational) terms tended to have more success in the programming exercise.
Kolar, Jan
2013-01-01
15 minutes talk on practical implementation of the Geospatial Manged Objects and the concepts described in the article "Bytecode Unification of Computable Geospatial Models". The time index of the presentation: 1m 43s Minimalistic GMO 4m 08s Functional GMO Definition 6m 07s Accessing GMOs from Shell using Scala scripts 9m 24s Viewing GMOs using Virtual Globe component 12m 03s GRIFIN implementation of GMO technology 12m 36s GMO software clients using GRIFIN ...
Excessive recreational computer use and food consumption behaviour among adolescents
Directory of Open Access Journals (Sweden)
Mao Yuping
2010-08-01
Full Text Available Abstract Introduction Using the 2005 California Health Interview Survey (CHIS data, we explore the association between excessive recreational computer use and specific food consumption behavior among California's adolescents aged 12-17. Method The adolescent component of CHIS 2005 measured the respondents' average number of hours spent on viewing TV on a weekday, the average number of hours spent on viewing TV on a weekend day, the average number of hours spent on playing with a computer on a weekday, and the average number of hours spent on playing with computers on a weekend day. We recode these four continuous variables into four variables of "excessive media use," and define more than three hours of using a medium per day as "excessive." These four variables are then used in logistic regressions to predict different food consumption behaviors on the previous day: having fast food, eating sugary food more than once, drinking sugary drinks more than once, and eating more than five servings of fruits and vegetables. We use the following variables as covariates in the logistic regressions: age, gender, race/ethnicity, parental education, household poverty status, whether born in the U.S., and whether living with two parents. Results Having fast food on the previous day is associated with excessive weekday TV viewing (O.R. = 1.38, p Conclusion Excessive recreational computer use independently predicts undesirable eating behaviors that could lead to overweight and obesity. Preventive measures ranging from parental/youth counseling to content regulations might be addressing the potential undesirable influence from excessive computer use on eating behaviors among children and adolescents.
Frank, M; Pacheco, Andreu
1998-01-01
This document is a first attempt to describe the LHCb computing model. The CPU power needed to process data for the event filter and reconstruction is estimated to be 2.2 \\Theta 106 MIPS. This will be installed at the experiment and will be reused during non data-taking periods for reprocessing. The maximal I/O of these activities is estimated to be around 40 MB/s.We have studied three basic models concerning the placement of the CPU resources for the other computing activities, Monte Carlo-simulation (1:4 \\Theta 106 MIPS) and physics analysis (0:5 \\Theta 106 MIPS): CPU resources may either be located at the physicist's homelab, national computer centres (Regional Centres) or at CERN.The CPU resources foreseen for analysis are sufficient to allow 100 concurrent analyses. It is assumed that physicists will work in physics groups that produce analysis data at an average rate of 4.2 MB/s or 11 TB per month. However, producing these group analysis data requires reading capabilities of 660 MB/s. It is further assu...
Energy Technology Data Exchange (ETDEWEB)
Kopper, Claudio, E-mail: claudio.kopper@nikhef.nl [NIKHEF, Science Park 105, 1098 XG Amsterdam (Netherlands)
2013-10-11
Completed in 2008, Antares is now the largest water Cherenkov neutrino telescope in the Northern Hemisphere. Its main goal is to detect neutrinos from galactic and extra-galactic sources. Due to the high background rate of atmospheric muons and the high level of bioluminescence, several on-line and off-line filtering algorithms have to be applied to the raw data taken by the instrument. To be able to handle this data stream, a dedicated computing infrastructure has been set up. The paper covers the main aspects of the current official Antares computing model. This includes an overview of on-line and off-line data handling and storage. In addition, the current usage of the “IceTray” software framework for Antares data processing is highlighted. Finally, an overview of the data storage formats used for high-level analysis is given.
Cilesiz, Sebnem
2009-01-01
Computer use is a widespread leisure activity for adolescents. Leisure contexts, such as Internet cafes, constitute specific social environments for computer use and may hold significant educational potential. This article reports a phenomenological study of adolescents' experiences of educational computer use at Internet cafes in Turkey. The…
Plasticity modeling & computation
Borja, Ronaldo I
2013-01-01
There have been many excellent books written on the subject of plastic deformation in solids, but rarely can one find a textbook on this subject. “Plasticity Modeling & Computation” is a textbook written specifically for students who want to learn the theoretical, mathematical, and computational aspects of inelastic deformation in solids. It adopts a simple narrative style that is not mathematically overbearing, and has been written to emulate a professor giving a lecture on this subject inside a classroom. Each section is written to provide a balance between the relevant equations and the explanations behind them. Where relevant, sections end with one or more exercises designed to reinforce the understanding of the “lecture.” Color figures enhance the presentation and make the book very pleasant to read. For professors planning to use this textbook for their classes, the contents are sufficient for Parts A and B that can be taught in sequence over a period of two semesters or quarters.
System modeling with Reservoir Computing
wyffels, Francis; Schrauwen, Benjamin; Stroobandt, Dirk
2008-01-01
Reservoir Computing is a novel technique which can be applied to a wide range of applications. In this work we demonstrate that Reservoir Computing can be used for black box nonlinear system modeling.We will use Reservoir Computing to model the output ﬂow of a heating tank with variable deadtime.
Heo, Gyun
2013-01-01
The purpose of the present study was to identify latent classes resting on early adolescents' change trajectory patterns in using computers and the Internet for learning and to test the effects of gender, self-control, self-esteem, and game use in South Korea. Latent growth mixture modeling (LGMM) was used to identify subpopulations in the Korea…
A Novel Forensic Computing Model
Institute of Scientific and Technical Information of China (English)
XU Yunfeng; LU Yansheng
2006-01-01
According to the requirement of computer forensic and network forensic, a novel forensic computing model is presented, which exploits XML/OEM/RM data model, Data fusion technology, forensic knowledgebase, inference mechanism of expert system and evidence mining engine. This model takes advantage of flexility and openness, so it can be widely used in mining evidence.
Computational modeling of concrete flow
DEFF Research Database (Denmark)
Roussel, Nicolas; Geiker, Mette Rica; Dufour, Frederic;
2007-01-01
This paper provides a general overview of the present status regarding computational modeling of the flow of fresh concrete. The computational modeling techniques that can be found in the literature may be divided into three main families: single fluid simulations, numerical modeling of discrete...
Pipe network flow analysis was among the first civil engineering applications programmed for solution on the early commercial mainframe computers in the 1960s. Since that time, advancements in analytical techniques and computing power have enabled us to solve systems with tens o...
Computational modeling in biomechanics
Mofrad, Mohammad
2010-01-01
This book provides a glimpse of the diverse and important roles that modern computational technology is playing in various areas of biomechanics. It includes unique chapters on ab initio quantum mechanical, molecular dynamic and scale coupling methods..
COMPUTATIONAL MODELS FOR SUSTAINABLE DEVELOPMENT
Monendra Grover; Rajesh Kumar; Tapan Kumar Mondal; S. Rajkumar
2011-01-01
Genetic erosion is a serious problem and computational models have been developed to prevent it. The computational modeling in this field not only includes (terrestrial) reserve design, but also decision modeling for related problems such as habitat restoration, marine reserve design, and nonreserve approaches to conservation management. Models have been formulated for evaluating tradeoffs between socioeconomic, biophysical, and spatial criteria in establishing marine reserves. The percolatio...
Computer-Aided Modeling Framework
DEFF Research Database (Denmark)
Fedorova, Marina; Sin, Gürkan; Gani, Rafiqul
Models are playing important roles in design and analysis of chemicals based products and the processes that manufacture them. Computer-aided methods and tools have the potential to reduce the number of experiments, which can be expensive and time consuming, and there is a benefit of working...... development and application. The proposed work is a part of the project for development of methods and tools that will allow systematic generation, analysis and solution of models for various objectives. It will use the computer-aided modeling framework that is based on a modeling methodology, which combines....... In this contribution, the concept of template-based modeling is presented and application is highlighted for the specific case of catalytic membrane fixed bed models. The modeling template is integrated in a generic computer-aided modeling framework. Furthermore, modeling templates enable the idea of model reuse...
Computation models of discourse
Energy Technology Data Exchange (ETDEWEB)
Brady, M.; Berwick, R.C.
1983-01-01
This book presents papers on artificial intelligence and natural language. Topics considered include recognizing intentions from natural language utterances, cooperative responses from a portable natural language database query system, natural language generation as a computational problem, focusing in the comprehension of definite anaphora, and factors in forming discourse-dependent descriptions.
Computational models of syntactic acquisition.
Yang, Charles
2012-03-01
The computational approach to syntactic acquisition can be fruitfully pursued by integrating results and perspectives from computer science, linguistics, and developmental psychology. In this article, we first review some key results in computational learning theory and their implications for language acquisition. We then turn to examine specific learning models, some of which exploit distributional information in the input while others rely on a constrained space of hypotheses, yet both approaches share a common set of characteristics to overcome the learning problem. We conclude with a discussion of how computational models connects with the empirical study of child grammar, making the case for computationally tractable, psychologically plausible and developmentally realistic models of acquisition. WIREs Cogn Sci 2012, 3:205-213. doi: 10.1002/wcs.1154 For further resources related to this article, please visit the WIREs website.
Cosmic Logic: a Computational Model
Vanchurin, Vitaly
2015-01-01
We initiate a formal study of logical inferences in context of the measure problem in cosmology or what we call cosmic logic. We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape an...
A Study of the Correlation between Computer Games and Adolescent Behavioral Problems
Shokouhi-Moqhaddam, Solmaz; Khezri-Moghadam, Noshiravan; Javanmard, Zeinab; Sarmadi-Ansar, Hassan; Aminaee, Mehran; Shokouhi-Moqhaddam, Majid; Zivari-Rahman, Mahmoud
2013-01-01
Background Today, due to developing communicative technologies, computer games and other audio-visual media as social phenomena, are very attractive and have a great effect on children and adolescents. The increasing popularity of these games among children and adolescents results in the public uncertainties about plausible harmful effects of these games. This study aimed to investigate the correlation between computer games and behavioral problems on male guidance school students. Methods Th...
Conti-Ramsden, Gina; Durkin, Kevin; Walker, Allan J.
2010-01-01
Individuals who are anxious about computers may be at a disadvantage in their learning. This investigation focused on the use of home computers for educational purposes. It compared computer anxiety in adolescents with and without a history of special needs related to language difficulties. Participants were 55 17-year-olds with specific language…
Trust Models in Ubiquitous Computing
DEFF Research Database (Denmark)
Nielsen, Mogens; Krukow, Karl; Sassone, Vladimiro
2008-01-01
We recapture some of the arguments for trust-based technologies in ubiquitous computing, followed by a brief survey of some of the models of trust that have been introduced in this respect. Based on this, we argue for the need of more formal and foundational trust models.......We recapture some of the arguments for trust-based technologies in ubiquitous computing, followed by a brief survey of some of the models of trust that have been introduced in this respect. Based on this, we argue for the need of more formal and foundational trust models....
Patient-Specific Computational Modeling
Peña, Estefanía
2012-01-01
This book addresses patient-specific modeling. It integrates computational modeling, experimental procedures, imagine clinical segmentation and mesh generation with the finite element method (FEM) to solve problems in computational biomedicine and bioengineering. Specific areas of interest include cardiovascular problems, ocular and muscular systems and soft tissue modeling. Patient-specific modeling has been the subject of serious research over the last seven years and interest in the area is continually growing and this area is expected to further develop in the near future.
Harju, Outi; Luukkonen, Anu-Helmi; Hakko, Helinä; Räsänen, Pirkko; Riala, Kaisa
2011-01-01
The Internet plays a major role in adolescents' free time activities and communication nowadays. The aim here was to investigate the possibility of an association of computers and video games or sports (team, individual) with psychiatric disorders among underage psychiatric inpatients. The series of adolescents (n = 508) had been diagnosed using semistructured interviews (K-SADS-PL). The results showed that an interest in computers and video games did not increase the risk of any specific psychiatric disorder among these adolescent inpatients, but the likelihood of a substance-related disorder was statistically significantly lower among the boys with computers as a hobby. Team sports were related to increased likelihood of conduct disorder among the boys, whereas the likelihood of an affective disorder was reduced. No such association was found in individual sports or among the girls. We conclude that social contacts and peers play an important role in preventing adolescent depression. PMID:21288072
Computer Modelling of Dynamic Processes
Directory of Open Access Journals (Sweden)
B. Rybakin
2000-10-01
Full Text Available Results of numerical modeling of dynamic problems are summed in the article up. These problems are characteristic for various areas of human activity, in particular for problem solving in ecology. The following problems are considered in the present work: computer modeling of dynamic effects on elastic-plastic bodies, calculation and determination of performances of gas streams in gas cleaning equipment, modeling of biogas formation processes.
Computational models of complex systems
Dabbaghian, Vahid
2014-01-01
Computational and mathematical models provide us with the opportunities to investigate the complexities of real world problems. They allow us to apply our best analytical methods to define problems in a clearly mathematical manner and exhaustively test our solutions before committing expensive resources. This is made possible by assuming parameter(s) in a bounded environment, allowing for controllable experimentation, not always possible in live scenarios. For example, simulation of computational models allows the testing of theories in a manner that is both fundamentally deductive and experimental in nature. The main ingredients for such research ideas come from multiple disciplines and the importance of interdisciplinary research is well recognized by the scientific community. This book provides a window to the novel endeavours of the research communities to present their works by highlighting the value of computational modelling as a research tool when investigating complex systems. We hope that the reader...
N.P.M. Ezendam (Nicole); A. Oenema (Anke); P.M. van de Looij-Jansen (Petra); J. Brug (Hans)
2008-01-01
textabstractComputer tailoring may be a promising technique for prevention of overweight in adolescents. However, very few well-developed, evidence-based computer-tailored interventions are available for this target group. We developed and evaluated a computer-tailored intervention for adolescents t
Directory of Open Access Journals (Sweden)
van de Looij-Jansen Petra M
2007-11-01
Full Text Available Abstract Background Computer tailoring may be a promising technique for prevention of overweight in adolescents. However, very few well-developed, evidence-based computer-tailored interventions are available for this target group. We developed and evaluated a computer-tailored intervention for adolescents targeting energy balance-related behaviours: i.e. consumption of snacks, sugar-sweetened beverages, fruit, vegetables, and fibre, physical activity, and sedentary behaviours. This paper describes the planned development of a school-based computer-tailored intervention aimed at improving energy balance-related behaviours in order to prevent excessive weight gain in adolescents, and the protocol for evaluating this intervention. Methods/design Intervention development: Informed by the Precaution Adoption Process Model and the Theory of Planned Behaviour, the computer-tailored intervention provided feedback on personal behaviour and suggestions on how to modify it. The intervention (VETisnietVET translated as 'FATaintPHAT' has been developed for use in the first year of secondary school during eight lessons. Evaluation design: The intervention will be evaluated in a cluster-randomised trial including 20 schools with a 4-months and a 2-years follow-up. Outcome measures are BMI, waist circumference, energy balance-related behaviours, and potential determinants of these behaviours. Process measures are appreciation of and satisfaction with the program, exposure to the program's content, and implementation facilitators and barriers measured among students and teachers. Discussion This project resulted in a theory and evidence-based intervention that can be implemented in a school setting. A large-scale randomised controlled trial with a short and long-term follow-up will provide sound statements about the effectiveness of this computer-tailored intervention in adolescents. Trial Registration ISRCTN15743786
Climate Modeling Computing Needs Assessment
Petraska, K. E.; McCabe, J. D.
2011-12-01
This paper discusses early findings of an assessment of computing needs for NASA science, engineering and flight communities. The purpose of this assessment is to document a comprehensive set of computing needs that will allow us to better evaluate whether our computing assets are adequately structured to meet evolving demand. The early results are interesting, already pointing out improvements we can make today to get more out of the computing capacity we have, as well as potential game changing innovations for the future in how we apply information technology to science computing. Our objective is to learn how to leverage our resources in the best way possible to do more science for less money. Our approach in this assessment is threefold: Development of use case studies for science workflows; Creating a taxonomy and structure for describing science computing requirements; and characterizing agency computing, analysis, and visualization resources. As projects evolve, science data sets increase in a number of ways: in size, scope, timelines, complexity, and fidelity. Generating, processing, moving, and analyzing these data sets places distinct and discernable requirements on underlying computing, analysis, storage, and visualization systems. The initial focus group for this assessment is the Earth Science modeling community within NASA's Science Mission Directorate (SMD). As the assessment evolves, this focus will expand to other science communities across the agency. We will discuss our use cases, our framework for requirements and our characterizations, as well as our interview process, what we learned and how we plan to improve our materials after using them in the first round of interviews in the Earth Science Modeling community. We will describe our plans for how to expand this assessment, first into the Earth Science data analysis and remote sensing communities, and then throughout the full community of science, engineering and flight at NASA.
Psychological Trauma as a Reason for Computer Game Addiction among Adolescents
Oskenbay, Fariza; Tolegenova, Aliya; Kalymbetova, Elmira; Chung, Man Cheung; Faizullina, Aida; Jakupov, Maksat
2016-01-01
This study explores psychological trauma as a reason for computer game addiction among adolescents. The findings of this study show that there is a connection between psychological trauma and computer game addiction. Some psychologists note that the main cause of any type of addiction derives from psychological trauma, and that finding such…
Developing a New Computer Game Attitude Scale for Taiwanese Early Adolescents
Liu, Eric Zhi-Feng; Lee, Chun-Yi; Chen, Jen-Huang
2013-01-01
With ever increasing exposure to computer games, gaining an understanding of the attitudes held by young adolescents toward such activities is crucial; however, few studies have provided scales with which to accomplish this. This study revisited the Computer Game Attitude Scale developed by Chappell and Taylor in 1997, reworking the overall…
DFI Computer Modeling Software (CMS)
Energy Technology Data Exchange (ETDEWEB)
Cazalet, E.G.; Deziel, L.B. Jr.; Haas, S.M.; Martin, T.W.; Nesbitt, D.M.; Phillips, R.L.
1979-10-01
The data base management system used to create, edit and store models data and solutions for the LEAP system is described. The software is entirely in FORTRAN-G for the IBM 370 series of computers and provides interface with a commercial data base system SYSTEM-2000.
Directory of Open Access Journals (Sweden)
Melissa A. Christino
2014-12-01
Full Text Available Anterior cruciate ligament (ACL surgery is being increasingly performed in the adolescent population. Computer navigation offers a reliable way to quantitatively measure knee stability during ACL reconstruction. A retrospective review of all adolescent patients (<18 years old who underwent computer-assisted primary single bundle ACL reconstruction by a single surgeon from 2007 to 2012 was performed. The average age was 15.8 years (SD 3.3. Female adolescents were found to have higher internal rotation than male adolescents both pre- (25.6° vs 21.7°, P=0.026 and post-reconstruction (20.1° vs 15.1°, P=0.005. Compared to adults, adolescents demonstrated significantly higher internal rotation both pre- (23.3° vs 21.5°, P=0.047 and post-reconstruction (17.1° vs 14.4°, P=0.003. They also had higher total rotation both pre- (40.9° vs 38.4°, P=0.02 and post-reconstruction when compared to adults (31.56° vs 28.67°, P=0.005. In adolescent patients, anterior translation was corrected more than rotation. Females had higher pre- and residual post-reconstruction internal rotation compared to males. When compared to adults, adolescents had increased internal rotation and total rotation both pre- and post-reconstruction.
COMPUTATIONAL MODELS FOR SUSTAINABLE DEVELOPMENT
Directory of Open Access Journals (Sweden)
Monendra Grover
2011-02-01
Full Text Available Genetic erosion is a serious problem and computational models have been developed to prevent it. The computational modeling in this field not only includes (terrestrial reserve design, but also decision modeling for related problems such as habitat restoration, marine reserve design, and nonreserve approaches to conservation management. Models have been formulated for evaluating tradeoffs between socioeconomic, biophysical, and spatial criteria in establishing marine reserves. The percolation theory and shortest path modeling have also been used. In this article we discuss the computational models that have been developed keeping in mind the sustainable developmentConservationists estimate that alarming rate at which biological species are disappearing will have an indelible impact on humanity. Targets which were set in 2002 to reduce the biodiversity loss by 2010 have not been met. The third global diversity outlook report said that loss of wildlife and habitats could not only exacerbate climate change through rising emissions but could also have a negative impact on food sources and industry.
Computer Profiling Based Model for Investigation
Directory of Open Access Journals (Sweden)
Neeraj Choudhary
2011-10-01
Full Text Available Computer profiling is used for computer forensic analysis, and proposes and elaborates on a novel model for use in computer profiling, the computer profiling object model. The computer profiling object model is an information model which models a computer as objects with various attributes and inter-relationships. These together provide the information necessary for a human investigator or an automated reasoning engine to make judgments as to the probable usage and evidentiary value of a computer system. The computer profiling object model can be implemented so as to support automated analysis to provide an investigator with the informationneeded to decide whether manual analysis is required.
FORENSIC COMPUTING MODELS: TECHNICAL OVERVIEW
Directory of Open Access Journals (Sweden)
Gulshan Shrivastava
2012-05-01
Full Text Available In this paper, we deal with introducing a technique of digital forensics for reconstruction of events or evidences after the commitment of a crime through any of the digital devices. It shows a clear transparency between Computer Forensics and Digital Forensics and gives a brief description about the classification of Digital Forensics. It has also been described that how the emergences of various digital forensic models help digital forensic practitioners and examiners in doing digital forensics. Further, discussed Merits and Demerits of the required models and review of every major model.
Visualizing ultrasound through computational modeling
Guo, Theresa W.
2004-01-01
The Doppler Ultrasound Hematocrit Project (DHP) hopes to find non-invasive methods of determining a person s blood characteristics. Because of the limits of microgravity and the space travel environment, it is important to find non-invasive methods of evaluating the health of persons in space. Presently, there is no well developed method of determining blood composition non-invasively. This projects hopes to use ultrasound and Doppler signals to evaluate the characteristic of hematocrit, the percentage by volume of red blood cells within whole blood. These non-invasive techniques may also be developed to be used on earth for trauma patients where invasive measure might be detrimental. Computational modeling is a useful tool for collecting preliminary information and predictions for the laboratory research. We hope to find and develop a computer program that will be able to simulate the ultrasound signals the project will work with. Simulated models of test conditions will more easily show what might be expected from laboratory results thus help the research group make informed decisions before and during experimentation. There are several existing Matlab based computer programs available, designed to interpret and simulate ultrasound signals. These programs will be evaluated to find which is best suited for the project needs. The criteria of evaluation that will be used are 1) the program must be able to specify transducer properties and specify transmitting and receiving signals, 2) the program must be able to simulate ultrasound signals through different attenuating mediums, 3) the program must be able to process moving targets in order to simulate the Doppler effects that are associated with blood flow, 4) the program should be user friendly and adaptable to various models. After a computer program is chosen, two simulation models will be constructed. These models will simulate and interpret an RF data signal and a Doppler signal.
Parallel computing in enterprise modeling.
Energy Technology Data Exchange (ETDEWEB)
Goldsby, Michael E.; Armstrong, Robert C.; Shneider, Max S.; Vanderveen, Keith; Ray, Jaideep; Heath, Zach; Allan, Benjamin A.
2008-08-01
This report presents the results of our efforts to apply high-performance computing to entity-based simulations with a multi-use plugin for parallel computing. We use the term 'Entity-based simulation' to describe a class of simulation which includes both discrete event simulation and agent based simulation. What simulations of this class share, and what differs from more traditional models, is that the result sought is emergent from a large number of contributing entities. Logistic, economic and social simulations are members of this class where things or people are organized or self-organize to produce a solution. Entity-based problems never have an a priori ergodic principle that will greatly simplify calculations. Because the results of entity-based simulations can only be realized at scale, scalable computing is de rigueur for large problems. Having said that, the absence of a spatial organizing principal makes the decomposition of the problem onto processors problematic. In addition, practitioners in this domain commonly use the Java programming language which presents its own problems in a high-performance setting. The plugin we have developed, called the Parallel Particle Data Model, overcomes both of these obstacles and is now being used by two Sandia frameworks: the Decision Analysis Center, and the Seldon social simulation facility. While the ability to engage U.S.-sized problems is now available to the Decision Analysis Center, this plugin is central to the success of Seldon. Because Seldon relies on computationally intensive cognitive sub-models, this work is necessary to achieve the scale necessary for realistic results. With the recent upheavals in the financial markets, and the inscrutability of terrorist activity, this simulation domain will likely need a capability with ever greater fidelity. High-performance computing will play an important part in enabling that greater fidelity.
Cosmic logic: a computational model
Vanchurin, Vitaly
2016-02-01
We initiate a formal study of logical inferences in context of the measure problem in cosmology or what we call cosmic logic. We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or Gödel number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies that it is impossible to construct CM machines to compute probabilities on the set of all CO machines using cut-off prescriptions. The cut-off measures can still be used if the set is reduced to include only machines which halt after a finite and predetermined number of steps.
Use of television, videogames, and computer among children and adolescents in Italy
Marinelli Paolo; Albano Luciana; Di Giuseppe Gabriella; Patriarca Alessandro; Angelillo Italo F
2009-01-01
Abstract Background This survey determined the practices about television (video inclusive), videogames, and computer use in children and adolescents in Italy. Methods A self-administered anonymous questionnaire covered socio-demographics; behaviour about television, videogames, computer, and sports; parental control over television, videogames, and computer. Results Overall, 54.1% and 61% always ate lunch or dinner in front of the television, 89.5% had a television in the bedroom while 52.5%...
The Role of Parents and Related Factors on Adolescent Computer Use
Epstein, Jennifer A.
2012-01-01
Background. Research suggested the importance of parents on their adolescents’ computer activity. Spending too much time on the computer for recreational purposes in particular has been found to be related to areas of public health concern in children/adolescents, including obesity and substance use. Design and Methods. The goal of the research was to determine the association between recreational computer use and potentially linked factors (parental monitoring, social influences to use com...
Minimal models of multidimensional computations.
Directory of Open Access Journals (Sweden)
Jeffrey D Fitzgerald
2011-03-01
Full Text Available The multidimensional computations performed by many biological systems are often characterized with limited information about the correlations between inputs and outputs. Given this limitation, our approach is to construct the maximum noise entropy response function of the system, leading to a closed-form and minimally biased model consistent with a given set of constraints on the input/output moments; the result is equivalent to conditional random field models from machine learning. For systems with binary outputs, such as neurons encoding sensory stimuli, the maximum noise entropy models are logistic functions whose arguments depend on the constraints. A constraint on the average output turns the binary maximum noise entropy models into minimum mutual information models, allowing for the calculation of the information content of the constraints and an information theoretic characterization of the system's computations. We use this approach to analyze the nonlinear input/output functions in macaque retina and thalamus; although these systems have been previously shown to be responsive to two input dimensions, the functional form of the response function in this reduced space had not been unambiguously identified. A second order model based on the logistic function is found to be both necessary and sufficient to accurately describe the neural responses to naturalistic stimuli, accounting for an average of 93% of the mutual information with a small number of parameters. Thus, despite the fact that the stimulus is highly non-Gaussian, the vast majority of the information in the neural responses is related to first and second order correlations. Our results suggest a principled and unbiased way to model multidimensional computations and determine the statistics of the inputs that are being encoded in the outputs.
Skin friction blistering: computer model.
Xing, Malcolm; Pan, Ning; Zhong, Wen; Maibach, Howard
2007-01-01
BACKGROUND/PURPOSE: Friction blisters, a common injury in sports and military operations, can adversely effect or even halt performance. Given its frequency and hazardous nature, recent research efforts appear limited. Blistering can be treated as a delamination phenomenon; similar issues in materials science have been extensively investigated in theory and experiment. An obstacle in studying blistering is the difficulty of conducting experiment on humans and animals. Computer modeling thus b...
Mohammadi, Mehrnoosh; RezaeiDehaghani, Abdollah; Mehrabi, Tayebeh; RezaeiDehaghani, Ali
2016-01-01
Background: As adolescents spend much time on playing computer games, their mental and social effects should be considered. The present study aimed to investigate the association between playing computer games and the mental and social health among male adolescents in Iran in 2014. Materials and Methods: This is a cross-sectional study conducted on 210 adolescents selected by multi-stage random sampling. Data were collected by Goldberg and Hillier general health (28 items) and Kiez social hea...
Cosmic Logic: a Computational Model
Vanchurin, Vitaly
2015-01-01
We describe a simple computational model of cosmic logic suitable for analysis of, for example, discretized cosmological systems. The construction is based on a particular model of computation, developed by Alan Turing, with cosmic observers (CO), cosmic measures (CM) and cosmic symmetries (CS) described by Turing machines. CO machines always start with a blank tape and CM machines take CO's Turing number (also known as description number or G{\\" o}del number) as input and output the corresponding probability. Similarly, CS machines take CO's Turing number as input, but output either one if the CO machines are in the same equivalence class or zero otherwise. We argue that CS machines are more fundamental than CM machines and, thus, should be used as building blocks in constructing CM machines. We prove the non-computability of a CS machine which discriminates between two classes of CO machines: mortal that halts in finite time and immortal that runs forever. In context of eternal inflation this result implies...
Intervention Strategies with Adolescents: The Newton Model.
Green, Matt
The problem of adolescent drug/alcohol abuse seems to have once again intensified during the 1980s. When the school is the only constant in an adolescent's life and when those same teenagers bring drugs and alcohol-related problems to school, the school has an obligation to implement change. The first step is identification of the problem. Beyond…
Computational Modeling in Tissue Engineering
2013-01-01
One of the major challenges in tissue engineering is the translation of biological knowledge on complex cell and tissue behavior into a predictive and robust engineering process. Mastering this complexity is an essential step towards clinical applications of tissue engineering. This volume discusses computational modeling tools that allow studying the biological complexity in a more quantitative way. More specifically, computational tools can help in: (i) quantifying and optimizing the tissue engineering product, e.g. by adapting scaffold design to optimize micro-environmental signals or by adapting selection criteria to improve homogeneity of the selected cell population; (ii) quantifying and optimizing the tissue engineering process, e.g. by adapting bioreactor design to improve quality and quantity of the final product; and (iii) assessing the influence of the in vivo environment on the behavior of the tissue engineering product, e.g. by investigating vascular ingrowth. The book presents examples of each...
MODEL IDENTIFICATION AND COMPUTER ALGEBRA.
Bollen, Kenneth A; Bauldry, Shawn
2010-10-01
Multiequation models that contain observed or latent variables are common in the social sciences. To determine whether unique parameter values exist for such models, one needs to assess model identification. In practice analysts rely on empirical checks that evaluate the singularity of the information matrix evaluated at sample estimates of parameters. The discrepancy between estimates and population values, the limitations of numerical assessments of ranks, and the difference between local and global identification make this practice less than perfect. In this paper we outline how to use computer algebra systems (CAS) to determine the local and global identification of multiequation models with or without latent variables. We demonstrate a symbolic CAS approach to local identification and develop a CAS approach to obtain explicit algebraic solutions for each of the model parameters. We illustrate the procedures with several examples, including a new proof of the identification of a model for handling missing data using auxiliary variables. We present an identification procedure for Structural Equation Models that makes use of CAS and that is a useful complement to current methods.
MODEL IDENTIFICATION AND COMPUTER ALGEBRA.
Bollen, Kenneth A; Bauldry, Shawn
2010-10-01
Multiequation models that contain observed or latent variables are common in the social sciences. To determine whether unique parameter values exist for such models, one needs to assess model identification. In practice analysts rely on empirical checks that evaluate the singularity of the information matrix evaluated at sample estimates of parameters. The discrepancy between estimates and population values, the limitations of numerical assessments of ranks, and the difference between local and global identification make this practice less than perfect. In this paper we outline how to use computer algebra systems (CAS) to determine the local and global identification of multiequation models with or without latent variables. We demonstrate a symbolic CAS approach to local identification and develop a CAS approach to obtain explicit algebraic solutions for each of the model parameters. We illustrate the procedures with several examples, including a new proof of the identification of a model for handling missing data using auxiliary variables. We present an identification procedure for Structural Equation Models that makes use of CAS and that is a useful complement to current methods. PMID:21769158
Business model elements impacting cloud computing adoption
DEFF Research Database (Denmark)
Bogataj, Kristina; Pucihar, Andreja; Sudzina, Frantisek
The paper presents a proposed research framework for identification of business model elements impacting Cloud Computing Adoption. We provide a definition of main Cloud Computing characteristics, discuss previous findings on factors impacting Cloud Computing Adoption, and investigate technology...... adoption theories, such as Diffusion of Innovations, Technology Acceptance Model, Unified Theory of Acceptance and Use of Technology. Further on, at research model for identification of Cloud Computing Adoption factors from a business model perspective is presented. The following business model building...
Los Alamos Center for Computer Security formal computer security model
Energy Technology Data Exchange (ETDEWEB)
Dreicer, J.S.; Hunteman, W.J.; Markin, J.T.
1989-01-01
This paper provides a brief presentation of the formal computer security model currently being developed at the Los Alamos Department of Energy (DOE) Center for Computer Security (CCS). The need to test and verify DOE computer security policy implementation first motivated this effort. The actual analytical model was a result of the integration of current research in computer security and previous modeling and research experiences. The model is being developed to define a generic view of the computer and network security domains, to provide a theoretical basis for the design of a security model, and to address the limitations of present formal mathematical models for computer security. The fundamental objective of computer security is to prevent the unauthorized and unaccountable access to a system. The inherent vulnerabilities of computer systems result in various threats from unauthorized access. The foundation of the Los Alamos DOE CCS model is a series of functionally dependent probability equations, relations, and expressions. The model is undergoing continued discrimination and evolution. We expect to apply the model to the discipline of the Bell and LaPadula abstract sets of objects and subjects. 6 refs.
International Conference on Computational Intelligence, Cyber Security, and Computational Models
Ramasamy, Vijayalakshmi; Sheen, Shina; Veeramani, C; Bonato, Anthony; Batten, Lynn
2016-01-01
This book aims at promoting high-quality research by researchers and practitioners from academia and industry at the International Conference on Computational Intelligence, Cyber Security, and Computational Models ICC3 2015 organized by PSG College of Technology, Coimbatore, India during December 17 – 19, 2015. This book enriches with innovations in broad areas of research like computational modeling, computational intelligence and cyber security. These emerging inter disciplinary research areas have helped to solve multifaceted problems and gained lot of attention in recent years. This encompasses theory and applications, to provide design, analysis and modeling of the aforementioned key areas.
Effects of Violent and Non-Violent Computer Game Content on Memory Performance in Adolescents
Maass, Asja; Kollhorster, Kirsten; Riediger, Annemarie; MacDonald, Vanessa; Lohaus, Arnold
2011-01-01
The present study focuses on the short-term effects of electronic entertainment media on memory and learning processes. It compares the effects of violent versus non-violent computer game content in a condition of playing and in another condition of watching the same game. The participants consisted of 83 female and 94 male adolescents with a mean…
Playing Violent Video and Computer Games and Adolescent Self-Concept.
Funk, Jeanne B.; Buchman, Debra D.
1996-01-01
Documents current adolescent electronic game-playing habits, exploring associations among preference for violent games, frequency and location of play, and self-concept. Identifies marked gender differences in game-playing habits and in scores on a self-perception profile. Finds that for girls, more time playing video or computer games is…
The relationship between computer games and quality of life in adolescents
Dolatabadi, Nayereh Kasiri; Eslami, Ahmad Ali; Mostafavi, Firooze; Hassanzade, Akbar; Moradi, Azam
2013-01-01
Background: Term of doing computer games among teenagers is growing rapidly. This popular phenomenon can cause physical and psychosocial issues in them. Therefore, this study examined the relationship between computer games and quality of life domains in adolescents aging 12-15 years. Materials and Methods: In a cross-sectional study using the 2-stage stratified cluster sampling method, 444 male and female students in Borkhar were selected. The data collection tool consisted of 1) World Healt...
Towards the Epidemiological Modeling of Computer Viruses
Xiaofan Yang; Lu-Xing Yang
2012-01-01
Epidemic dynamics of computer viruses is an emerging discipline aiming to understand the way that computer viruses spread on networks. This paper is intended to establish a series of rational epidemic models of computer viruses. First, a close inspection of some common characteristics shared by all typical computer viruses clearly reveals the flaws of previous models. Then, a generic epidemic model of viruses, which is named as the SLBS model, is proposed. Finally, diverse generalizations of ...
Abedini, Yasamin; Zamani, Bibi Eshrat; Kheradmand, Ali; Rajabizadeh, Ghodratollah
2012-01-01
Background Addiction to computer (video) games in adolescents and its relationship with educational progress has recently attracted the attention of rearing and education experts as well as organizations and institutes involved in physical and mental health. The current research attempted to propose a structural model of the relationships between parenting styles, mothers’ occupation status, and addiction to computer games, self-control, and educational progress of secondary school students. ...
Directory of Open Access Journals (Sweden)
Pulkkinen Lea
2007-02-01
Full Text Available Abstract Background Overweight in children and adolescents has reached dimensions of a global epidemic during recent years. Simultaneously, information and communication technology use has rapidly increased. Methods A population-based sample of Finnish twins born in 1983–1987 (N = 4098 was assessed by self-report questionnaires at 17 y during 2000–2005. The association of overweight (defined by Cole's BMI-for-age cut-offs with computer and cell phone use and ownership was analyzed by logistic regression and their association with BMI by linear regression models. The effect of twinship was taken into account by correcting for clustered sampling of families. All models were adjusted for gender, physical exercise, and parents' education and occupational class. Results The proportion of adolescents who did not have a computer at home decreased from 18% to 8% from 2000 to 2005. Compared to them, having a home computer (without an Internet connection was associated with a higher risk of overweight (odds ratio 2.3, 95% CI 1.4 to 3.8 and BMI (beta coefficient 0.57, 95% CI 0.15 to 0.98. However, having a computer with an Internet connection was not associated with weight status. Belonging to the highest quintile (OR 1.8 95% CI 1.2 to 2.8 and second-highest quintile (OR 1.6 95% CI 1.1 to 2.4 of weekly computer use was positively associated with overweight. The proportion of adolescents without a personal cell phone decreased from 12% to 1% across 2000 to 2005. There was a positive linear trend of increasing monthly phone bill with BMI (beta 0.18, 95% CI 0.06 to 0.30, but the association of a cell phone bill with overweight was very weak. Conclusion Time spent using a home computer was associated with an increased risk of overweight. Cell phone use correlated weakly with BMI. Increasing use of information and communication technology may be related to the obesity epidemic among adolescents.
A Computationally Efficient Bedrock Model
Fastook, J. L.
2002-05-01
Full treatments of the Earth's crust, mantle, and core for ice sheet modeling are often computationally overwhelming, in that the requirements to calculate a full self-gravitating spherical Earth model for the time-varying load history of an ice sheet are considerably greater than the computational requirements for the ice dynamics and thermodynamics combined. For this reason, we adopt a ``reasonable'' approximation for the behavior of the deforming bedrock beneath the ice sheet. This simpler model of the Earth treats the crust as an elastic plate supported from below by a hydrostatic fluid. Conservation of linear and angular momentum for an elastic plate leads to the classical Poisson-Kirchhoff fourth order differential equation in the crustal displacement. By adding a time-dependent term this treatment allows for an exponentially-decaying response of the bed to loading and unloading events. This component of the ice sheet model (along with the ice dynamics and thermodynamics) is solved using the Finite Element Method (FEM). C1 FEMs are difficult to implement in more than one dimension, and as such the engineering community has turned away from classical Poisson-Kirchhoff plate theory to treatments such as Reissner-Mindlin plate theory, which are able to accommodate transverse shear and hence require only C0 continuity of basis functions (only the function, and not the derivative, is required to be continuous at the element boundary) (Hughes 1987). This method reduces the complexity of the C1 formulation by adding additional degrees of freedom (the transverse shear in x and y) at each node. This ``reasonable'' solution is compared with two self-gravitating spherical Earth models (1. Ivins et al. (1997) and James and Ivins (1998) } and 2. Tushingham and Peltier 1991 ICE3G run by Jim Davis and Glenn Milne), as well as with preliminary results of residual rebound rates measured with GPS by the BIFROST project. Modeled responses of a simulated ice sheet experiencing a
Computational Chemistry in the Pharmaceutical Industry: From Childhood to Adolescence.
Hillisch, Alexander; Heinrich, Nikolaus; Wild, Hanno
2015-12-01
Computational chemistry within the pharmaceutical industry has grown into a field that proactively contributes to many aspects of drug design, including target selection and lead identification and optimization. While methodological advancements have been key to this development, organizational developments have been crucial to our success as well. In particular, the interaction between computational and medicinal chemistry and the integration of computational chemistry into the entire drug discovery process have been invaluable. Over the past ten years we have shaped and developed a highly efficient computational chemistry group for small-molecule drug discovery at Bayer HealthCare that has significantly impacted the clinical development pipeline. In this article we describe the setup and tasks of the computational group and discuss external collaborations. We explain what we have found to be the most valuable and productive methods and discuss future directions for computational chemistry method development. We share this information with the hope of igniting interesting discussions around this topic.
Perceived problems with computer gaming and internet use among adolescents
DEFF Research Database (Denmark)
Holstein, Bjørn E; Pedersen, Trine Pagh; Bendtsen, Pernille;
2014-01-01
BACKGROUND: Existing instruments for measuring problematic computer and console gaming and internet use are often lengthy and often based on a pathological perspective. The objective was to develop and present a new and short non-clinical measurement tool for perceived problems related to computer...... on weekdays on computer- and console-gaming and internet use for communication and surfing. The outcome measures were three indexes on perceived problems related to computer and console gaming and internet use. RESULTS: The three new indexes showed high face validity and acceptable internal consistency. Most...... schoolchildren with high screen time did not experience problems related to computer use. Still, there was a strong and graded association between time use and perceived problems related to computer gaming, console gaming (only boys) and internet use, odds ratios ranging from 6.90 to 10.23. CONCLUSION: The three...
Towards the Epidemiological Modeling of Computer Viruses
Directory of Open Access Journals (Sweden)
Xiaofan Yang
2012-01-01
Full Text Available Epidemic dynamics of computer viruses is an emerging discipline aiming to understand the way that computer viruses spread on networks. This paper is intended to establish a series of rational epidemic models of computer viruses. First, a close inspection of some common characteristics shared by all typical computer viruses clearly reveals the flaws of previous models. Then, a generic epidemic model of viruses, which is named as the SLBS model, is proposed. Finally, diverse generalizations of the SLBS model are suggested. We believe this work opens a door to the full understanding of how computer viruses prevail on the Internet.
A Computational Model of Music Composition
Oberholtzer, Josiah W.
2015-01-01
This thesis documents my research into formalized score control, in order to demonstrate a computational model of music composition. When working computationally, models provide an explicit formal description of what objects exist within a given domain, how they behave, and what transformations they afford. The clearer the model becomes, the easier it is to extend and to construct increasingly higher-order abstractions around that model. In other words, a clear computational model of music no...
A twin study of computer anxiety in Turkish adolescents.
Deryakulu, Deniz; Calışkan, Erkan
2012-04-01
The present study investigated computer anxiety within a sample of Turkish twins aged 10-18. A total of 185 twin-pairs participated in the study. Of the twins, 64 pairs (34.6 percent) were monozygotic (MZ) and 121 pairs (65.4 percent) were dizygotic (DZ). Of the 121 DZ twins, 54 pairs (44.63 percent) were same-sex twins and 67 pairs (55.37 percent) were opposite-sex twins. Computer anxiety was assessed using Computer Anxiety Rating Scale-Turkish Version (CARS-TV), one of the three main scales of "Measuring Technophobia Instruments" developed by Rosen and Weil. The results of paired t test comparisons showed no significant differences in MZ and same-sex DZ twin-pairs' levels of computer anxiety. On the other hand, a significant difference was found in opposite-sex DZ twin-pairs' level of computer anxiety. Interesting enough, males appeared to be more computer anxious than their female co-twins. In the present study, using Falconer's formula, heritability estimate for computer anxiety was derived from correlations based on MZ and DZ twins' mean scores on CARS-TV. The results showed that 57 percent of the variance in computer anxiety was from genetics and 41.5 percent was from nonshared environmental factors. Shared environmental influence, on the other hand, was very small and negligible. Interpretations of results and potential directions for future research are presented.
A twin study of computer anxiety in Turkish adolescents.
Deryakulu, Deniz; Calışkan, Erkan
2012-04-01
The present study investigated computer anxiety within a sample of Turkish twins aged 10-18. A total of 185 twin-pairs participated in the study. Of the twins, 64 pairs (34.6 percent) were monozygotic (MZ) and 121 pairs (65.4 percent) were dizygotic (DZ). Of the 121 DZ twins, 54 pairs (44.63 percent) were same-sex twins and 67 pairs (55.37 percent) were opposite-sex twins. Computer anxiety was assessed using Computer Anxiety Rating Scale-Turkish Version (CARS-TV), one of the three main scales of "Measuring Technophobia Instruments" developed by Rosen and Weil. The results of paired t test comparisons showed no significant differences in MZ and same-sex DZ twin-pairs' levels of computer anxiety. On the other hand, a significant difference was found in opposite-sex DZ twin-pairs' level of computer anxiety. Interesting enough, males appeared to be more computer anxious than their female co-twins. In the present study, using Falconer's formula, heritability estimate for computer anxiety was derived from correlations based on MZ and DZ twins' mean scores on CARS-TV. The results showed that 57 percent of the variance in computer anxiety was from genetics and 41.5 percent was from nonshared environmental factors. Shared environmental influence, on the other hand, was very small and negligible. Interpretations of results and potential directions for future research are presented. PMID:22394420
The role of parents and related factors on adolescent computer use
Directory of Open Access Journals (Sweden)
Jennifer A. Epstein
2012-02-01
Full Text Available Background. Research suggested the importance of parents on their adolescents’ computer activity. Spending too much time on the computer for recreational purposes in particular has been found to be related to areas of public health concern in children/adolescents, including obesity and substance use. Design and Methods. The goal of the research was to determine the association between recreational computer use and potentially linked factors (parental monitoring, social influences to use computers including parents, age of first computer use, self-control, and particular internet activities. Participants (aged 13-17 years and residing in the United States were recruited via the Internet to complete an anonymous survey online using a survey tool. The target sample of 200 participants who completed the survey was achieved. The sample’s average age was 16 and was 63% girls. Results. A set of regressions with recreational computer use as dependent variables were run. Conclusions. Less parental monitoring, younger age at first computer use, listening or downloading music from the internet more frequently, using the internet for educational purposes less frequently, and parent’s use of the computer for pleasure was related to spending a greater percentage of time on non-school computer use. These findings suggest the importance of parental monitoring and parental computer use on their children’s own computer use, and the influence of some internet activities on adolescent computer use. Finally, programs aimed at parents to help them increase the age when their children start using computers and learn how to place limits on recreational computer use are needed.
A Longitudinal Family-Level Model of Arab Muslim Adolescent Behavior Problems
Aroian, Karen J.; Templin, Thomas N.; Hough, Edythe Ellison; Ramaswamy, Vidya; Katz, Anne
2011-01-01
Arab-American Muslim adolescents in immigrant families face a number of challenges that put them at risk for behavior problems. This study of Arab-American Muslim Adolescents and their relatively recent immigrant mothers tested a longitudinal family-level model of adolescent behavior problems. Mother-adolescent dyads (N = 530) completed measures…
Adolescent computer use and alcohol use: what are the role of quantity and content of computer use?
Epstein, Jennifer A
2011-05-01
The purpose of this study was to examine the relationship between computer use and alcohol use among adolescents. In particular, the goal of the research was to determine the role of lifetime drinking and past month drinking on quantity as measured by amount of time on the computer (for school work and excluding school work) and on content as measured by the frequency of a variety of activities on the internet (e.g., e-mail, searching for information, social networking, listen to/download music). Participants (aged 13-17 years and residing in the United States) were recruited via the internet to complete an anonymous survey online using a popular survey tool (N=270). Their average age was 16 and the sample was predominantly female (63% girls). A series of analyses was conducted with the computer use measures as dependent variables (hours on the computer per week for school work and excluding school work; various internet activities including e-mail, searching for information, social networking, listen to/download music) controlling for gender, age, academic performance and age of first computer use. Based on the results, past month drinkers used the computer more hours per week excluding school work than those who did not. As expected, there were no differences in hours based on alcohol use for computer use for school work. Drinking also had relationships with more frequent social networking and listening to/downloading music. These findings suggest that both quantity and content of computer use were related to adolescent drinking. PMID:21295917
Lang, Jason M.; Waterman, Jill; Baker, Bruce L.
2009-01-01
Computeen, a preventive technology and psychosocial skills development program for at-risk adolescents, was designed to improve computer skills, self-esteem, and school attitudes, and reduce behavior problems, by combining elements of community-based and empirically supported prevention programs. Fifty-five mostly Latino adolescents from 12 to 16…
Prevalence of headache in adolescents and association with use of computer and videogames.
Xavier, Michelle Katherine Andrade; Pitangui, Ana Carolina Rodarti; Silva, Georgia Rodrigues Reis; Oliveira, Valéria Mayaly Alves de; Beltrão, Natália Barros; Araújo, Rodrigo Cappato de
2015-11-01
The aim of this study was to determine the prevalence of headache in adolescents and its association with excessive use of electronic devices and games. The sample comprised 954 adolescents of both sexes (14 to 19 years) who answered a questionnaire about use of computers and electronic games, presence of headache and physical activity. The binary and multinomial logistic regression, with significance level of 5% was used for inferential analysis. The prevalence of headache was 80.6%. The excessive use of electronics devices proved to be a risk factor (OR = 1.21) for headache. Subjects aged between 14 and 16 years were less likely to report headache (OR = 0.64). Regarding classification, 17.9% of adolescents had tension-type headache, 19.3% had migraine and 43.4% other types of headache. The adolescents aged form 14 to 16 years had lower chance (OR ≤ 0.68) to report the tension-type headache and other types of headache. The excessive use of digital equipment, electronic games and attending the third year of high school proved to be risk factors for migraine-type development (OR ≥ 1.84). There was a high prevalence of headache in adolescents and high-time use of electronic devices. We observed an association between excessive use of electronic devices and the presence of headache, and this habit is considered a risk factor, especially for the development of migraine-type. PMID:26602725
Prevalence of headache in adolescents and association with use of computer and videogames.
Xavier, Michelle Katherine Andrade; Pitangui, Ana Carolina Rodarti; Silva, Georgia Rodrigues Reis; Oliveira, Valéria Mayaly Alves de; Beltrão, Natália Barros; Araújo, Rodrigo Cappato de
2015-11-01
The aim of this study was to determine the prevalence of headache in adolescents and its association with excessive use of electronic devices and games. The sample comprised 954 adolescents of both sexes (14 to 19 years) who answered a questionnaire about use of computers and electronic games, presence of headache and physical activity. The binary and multinomial logistic regression, with significance level of 5% was used for inferential analysis. The prevalence of headache was 80.6%. The excessive use of electronics devices proved to be a risk factor (OR = 1.21) for headache. Subjects aged between 14 and 16 years were less likely to report headache (OR = 0.64). Regarding classification, 17.9% of adolescents had tension-type headache, 19.3% had migraine and 43.4% other types of headache. The adolescents aged form 14 to 16 years had lower chance (OR ≤ 0.68) to report the tension-type headache and other types of headache. The excessive use of digital equipment, electronic games and attending the third year of high school proved to be risk factors for migraine-type development (OR ≥ 1.84). There was a high prevalence of headache in adolescents and high-time use of electronic devices. We observed an association between excessive use of electronic devices and the presence of headache, and this habit is considered a risk factor, especially for the development of migraine-type.
Cupola Furnace Computer Process Model
Energy Technology Data Exchange (ETDEWEB)
Seymour Katz
2004-12-31
The cupola furnace generates more than 50% of the liquid iron used to produce the 9+ million tons of castings annually. The cupola converts iron and steel into cast iron. The main advantages of the cupola furnace are lower energy costs than those of competing furnaces (electric) and the ability to melt less expensive metallic scrap than the competing furnaces. However the chemical and physical processes that take place in the cupola furnace are highly complex making it difficult to operate the furnace in optimal fashion. The results are low energy efficiency and poor recovery of important and expensive alloy elements due to oxidation. Between 1990 and 2004 under the auspices of the Department of Energy, the American Foundry Society and General Motors Corp. a computer simulation of the cupola furnace was developed that accurately describes the complex behavior of the furnace. When provided with the furnace input conditions the model provides accurate values of the output conditions in a matter of seconds. It also provides key diagnostics. Using clues from the diagnostics a trained specialist can infer changes in the operation that will move the system toward higher efficiency. Repeating the process in an iterative fashion leads to near optimum operating conditions with just a few iterations. More advanced uses of the program have been examined. The program is currently being combined with an ''Expert System'' to permit optimization in real time. The program has been combined with ''neural network'' programs to affect very easy scanning of a wide range of furnace operation. Rudimentary efforts were successfully made to operate the furnace using a computer. References to these more advanced systems will be found in the ''Cupola Handbook''. Chapter 27, American Foundry Society, Des Plaines, IL (1999).
Computational biomechanics for medicine imaging, modeling and computing
Doyle, Barry; Wittek, Adam; Nielsen, Poul; Miller, Karol
2016-01-01
The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements. This volume comprises eighteen of the newest approaches and applications of computational biomechanics, from researchers in Australia, New Zealand, USA, UK, Switzerland, Scotland, France and Russia. Some of the interesting topics discussed are: tailored computational models; traumatic brain injury; soft-tissue mechanics; medical image analysis; and clinically-relevant simulations. One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. We hope the research presented within this book series will contribute to overcoming this grand challenge.
Financial aspects of cloud computing business models
Jäätmaa, Jaakko
2010-01-01
The purpose of the study was to explore financial aspects of cloud computing business models from information technology (IT) services provider’s perspective. The financial aspects were divided into revenue model and related pricing mechanisms and cost structure and related cost accounting mechanisms according to business model ontology. Cloud computing is a new computing paradigm and the latest megatrend in IT industry developed as a result of the convergence of numerous new and existing...
Pervasive Computing and Prosopopoietic Modelling
DEFF Research Database (Denmark)
Michelsen, Anders Ib
2011-01-01
This article treats the philosophical underpinnings of the notions of ubiquity and pervasive computing from a historical perspective. The current focus on these notions reflects the ever increasing impact of new media and the underlying complexity of computed function in the broad sense of ICT...... that have spread vertiginiously since Mark Weiser coined the term ‘pervasive’, e.g., digitalised sensoring, monitoring, effectuation, intelligence, and display. Whereas Weiser’s original perspective may seem fulfilled since computing is everywhere, in his and Seely Brown’s (1997) terms, ‘invisible......’, on the horizon, ’calm’, it also points to a much more important and slightly different perspective: that of creative action upon novel forms of artifice. Most importantly for this article, ubiquity and pervasive computing is seen to point to the continuous existence throughout the computational heritage since...
Computational Models for Nonlinear Aeroelastic Systems Project
National Aeronautics and Space Administration — Clear Science Corp. and Duke University propose to develop and demonstrate new and efficient computational methods of modeling nonlinear aeroelastic systems. The...
Model of computation for Fourier optical processors
Naughton, Thomas J.
2000-05-01
We present a novel and simple theoretical model of computation that captures what we believe are the most important characteristics of an optical Fourier transform processor. We use this abstract model to reason about the computational properties of the physical systems it describes. We define a grammar for our model's instruction language, and use it to write algorithms for well-known filtering and correlation techniques. We also suggest suitable computational complexity measures that could be used to analyze any coherent optical information processing technique, described with the language, for efficiency. Our choice of instruction language allows us to argue that algorithms describable with this model should have optical implementations that do not require a digital electronic computer to act as a master unit. Through simulation of a well known model of computation from computer theory we investigate the general-purpose capabilities of analog optical processors.
Computational nanophotonics modeling and applications
Musa, Sarhan M
2013-01-01
This reference offers tools for engineers, scientists, biologists, and others working with the computational techniques of nanophotonics. It introduces the key concepts of computational methods in a manner that is easily digestible for newcomers to the field. The book also examines future applications of nanophotonics in the technical industry and covers new developments and interdisciplinary research in engineering, science, and medicine. It provides an overview of the key computational nanophotonics and describes the technologies with an emphasis on how they work and their key benefits.
A computational model for feature binding
Institute of Scientific and Technical Information of China (English)
SHI ZhiWei; SHI ZhongZhi; LIU Xi; SHI ZhiPing
2008-01-01
The "Binding Problem" is an important problem across many disciplines, including psychology, neuroscience, computational modeling, and even philosophy. In this work, we proposed a novel computational model, Bayesian Linking Field Model, for feature binding in visual perception, by combining the idea of noisy neuron model, Bayesian method, Linking Field Network and competitive mechanism.Simulation Experiments demonstrated that our model perfectly fulfilled the task of feature binding in visual perception and provided us some enlightening idea for future research.
A computational model for feature binding
Institute of Scientific and Technical Information of China (English)
2008-01-01
The "Binding Problem" is an important problem across many disciplines, including psychology, neuroscience, computational modeling, and even philosophy. In this work, we proposed a novel computational model, Bayesian Linking Field Model, for feature binding in visual perception, by combining the idea of noisy neuron model, Bayesian method, Linking Field Network and competitive mechanism. Simulation Experiments demonstrated that our model perfectly fulfilled the task of feature binding in visual perception and provided us some enlightening idea for future research.
Adolescent Emotional Maturation through Divergent Models of Brain Organization
Oron Semper, Jose V.; Murillo, Jose I.; Bernacer, Javier
2016-01-01
In this article we introduce the hypothesis that neuropsychological adolescent maturation, and in particular emotional management, may have opposing explanations depending on the interpretation of the assumed brain architecture, that is, whether a componential computational account (CCA) or a dynamic systems perspective (DSP) is used. According to CCA, cognitive functions are associated with the action of restricted brain regions, and this association is temporally stable; by contrast, DSP argues that cognitive functions are better explained by interactions between several brain areas, whose engagement in specific functions is temporal and context-dependent and based on neural reuse. We outline the main neurobiological facts about adolescent maturation, focusing on the neuroanatomical and neurofunctional processes associated with adolescence. We then explain the importance of emotional management in adolescent maturation. We explain the interplay between emotion and cognition under the scope of CCA and DSP, both at neural and behavioral levels. Finally, we justify why, according to CCA, emotional management is understood as regulation, specifically because the cognitive aspects of the brain are in charge of regulating emotion-related modules. However, the key word in DSP is integration, since neural information from different brain areas is integrated from the beginning of the process. Consequently, although the terms should not be conceptually confused, there is no cognition without emotion, and vice versa. Thus, emotional integration is not an independent process that just happens to the subject, but a crucial part of personal growth. Considering the importance of neuropsychological research in the development of educational and legal policies concerning adolescents, we intend to expose that the holistic view of adolescents is dependent on whether one holds the implicit or explicit interpretation of brain functioning. PMID:27602012
Adolescent Emotional Maturation through Divergent Models of Brain Organization.
Oron Semper, Jose V; Murillo, Jose I; Bernacer, Javier
2016-01-01
In this article we introduce the hypothesis that neuropsychological adolescent maturation, and in particular emotional management, may have opposing explanations depending on the interpretation of the assumed brain architecture, that is, whether a componential computational account (CCA) or a dynamic systems perspective (DSP) is used. According to CCA, cognitive functions are associated with the action of restricted brain regions, and this association is temporally stable; by contrast, DSP argues that cognitive functions are better explained by interactions between several brain areas, whose engagement in specific functions is temporal and context-dependent and based on neural reuse. We outline the main neurobiological facts about adolescent maturation, focusing on the neuroanatomical and neurofunctional processes associated with adolescence. We then explain the importance of emotional management in adolescent maturation. We explain the interplay between emotion and cognition under the scope of CCA and DSP, both at neural and behavioral levels. Finally, we justify why, according to CCA, emotional management is understood as regulation, specifically because the cognitive aspects of the brain are in charge of regulating emotion-related modules. However, the key word in DSP is integration, since neural information from different brain areas is integrated from the beginning of the process. Consequently, although the terms should not be conceptually confused, there is no cognition without emotion, and vice versa. Thus, emotional integration is not an independent process that just happens to the subject, but a crucial part of personal growth. Considering the importance of neuropsychological research in the development of educational and legal policies concerning adolescents, we intend to expose that the holistic view of adolescents is dependent on whether one holds the implicit or explicit interpretation of brain functioning. PMID:27602012
A model nursing computer resource center.
Mueller, Sheryl S; Pullen, Richard L; McGee, K Sue
2002-01-01
Nursing graduates are required to demonstrate computer technology skills and critical reflective thinking skills in the workplace. The authors discuss a model computer resource center that enhances the acquisition of these requisite skills by students in both an associate degree and vocational nursing program. The computer resource center maximizes student learning and promotes faculty effectiveness and efficiency by a "full-service" approach to computerized testing, information technology instruction, online research, and interactive computer program practice. PMID:12023644
Regional brain activation associated with addiction of computer games in adolescents
Energy Technology Data Exchange (ETDEWEB)
Yoo, Y. H.; Shin, O. J.; Ko, Y. W.; Kim, H. J.; Yun, M. J.; Lee, J. D. [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)
2001-07-01
Excessive computer game (CG) playing may cause not only behavioral addiction, but also potential negative effects on developing brain. It is necessary to reveal how brain is affected by excessive use of CG playing and behavioral addiction of it. By using PET, we address the issue seeking to identifying patterns of regional brain activation associated with behavioral addiction and excessive use of CG playing by adolescents. 6 normal control and 8 adolescents who were met by the criteria of behavioral addiction on the survey as addiction groups with an addiction of CG playing were participated. Initial screening survey which is the adapted version of DSM-IV for pathologic gambling was done. PET were performed twice in each participants both during resting state and after 20 min playing of CG. Psychological test including Youth Self Report (YSR), memory and attention test and vocabulary item from KWAIS were performed. Scores of the vocabulary item from KWAIS and social competence from YSR were significantly lower in the addiction group. On PET, addiction group showed higher resting metabolism on inferior frontal, premotor, prefrontal and superior temporal area. Adolescents with addiction of CG revealed different patterns of regional brain activation comparing to control groups. These suggest behavioral addiction and excessive use of CG may result in functional alteration of developing brain in adolescents.
Regional brain activation associated with addiction of computer games in adolescents
International Nuclear Information System (INIS)
Excessive computer game (CG) playing may cause not only behavioral addiction, but also potential negative effects on developing brain. It is necessary to reveal how brain is affected by excessive use of CG playing and behavioral addiction of it. By using PET, we address the issue seeking to identifying patterns of regional brain activation associated with behavioral addiction and excessive use of CG playing by adolescents. 6 normal control and 8 adolescents who were met by the criteria of behavioral addiction on the survey as addiction groups with an addiction of CG playing were participated. Initial screening survey which is the adapted version of DSM-IV for pathologic gambling was done. PET were performed twice in each participants both during resting state and after 20 min playing of CG. Psychological test including Youth Self Report (YSR), memory and attention test and vocabulary item from KWAIS were performed. Scores of the vocabulary item from KWAIS and social competence from YSR were significantly lower in the addiction group. On PET, addiction group showed higher resting metabolism on inferior frontal, premotor, prefrontal and superior temporal area. Adolescents with addiction of CG revealed different patterns of regional brain activation comparing to control groups. These suggest behavioral addiction and excessive use of CG may result in functional alteration of developing brain in adolescents
Computer Aided Continuous Time Stochastic Process Modelling
DEFF Research Database (Denmark)
Kristensen, N.R.; Madsen, Henrik; Jørgensen, Sten Bay
2001-01-01
A grey-box approach to process modelling that combines deterministic and stochastic modelling is advocated for identification of models for model-based control of batch and semi-batch processes. A computer-aided tool designed for supporting decision-making within the corresponding modelling cycle...
COLD-SAT Dynamic Model Computer Code
Bollenbacher, G.; Adams, N. S.
1995-01-01
COLD-SAT Dynamic Model (CSDM) computer code implements six-degree-of-freedom, rigid-body mathematical model for simulation of spacecraft in orbit around Earth. Investigates flow dynamics and thermodynamics of subcritical cryogenic fluids in microgravity. Consists of three parts: translation model, rotation model, and slosh model. Written in FORTRAN 77.
Large Scale Computations in Air Pollution Modelling
DEFF Research Database (Denmark)
Zlatev, Z.; Brandt, J.; Builtjes, P. J. H.;
Proceedings of the NATO Advanced Research Workshop on Large Scale Computations in Air Pollution Modelling, Sofia, Bulgaria, 6-10 July 1998......Proceedings of the NATO Advanced Research Workshop on Large Scale Computations in Air Pollution Modelling, Sofia, Bulgaria, 6-10 July 1998...
Leverage points in a computer model
Janošek, Michal
2016-06-01
This article is focused on the analysis of the leverage points (developed by D. Meadows) in a computer model. The goal is to find out if there is a possibility to find these points of leverage in a computer model (on the example of a predator-prey model) and to determine how the particular parameters, their ranges and monitored variables of the model are associated with the concept of leverage points.
Developmental Trajectories of Adolescent Popularity: A Growth Curve Modelling Analysis
Cillessen, Antonius H. N.; Borch, Casey
2006-01-01
Growth curve modelling was used to examine developmental trajectories of sociometric and perceived popularity across eight years in adolescence, and the effects of gender, overt aggression, and relational aggression on these trajectories. Participants were 303 initially popular students (167 girls, 136 boys) for whom sociometric data were…
Model Railroading and Computer Fundamentals
McCormick, John W.
2007-01-01
Less than one half of one percent of all processors manufactured today end up in computers. The rest are embedded in other devices such as automobiles, airplanes, trains, satellites, and nearly every modern electronic device. Developing software for embedded systems requires a greater knowledge of hardware than developing for a typical desktop…
Adaptive approximate Bayesian computation for complex models
Lenormand, Maxime; Deffuant, Guillaume
2011-01-01
Approximate Bayesian computation (ABC) is a family of computational techniques in Bayesian statistics. These techniques allow to fit a model to data without relying on the computation of the model likelihood. They instead require to simulate a large number of times the model to be fitted. A number of refinements to the original rejection-based ABC scheme have been proposed, including the sequential improvement of posterior distributions. This technique allows to decrease the number of model simulations required, but it still presents several shortcomings which are particularly problematic for costly to simulate complex models. We here provide a new algorithm to perform adaptive approximate Bayesian computation, which is shown to perform better on both a toy example and a complex social model.
Computational Modeling of Cardiac Electromechanics
Krishnamoorthi, Shankarjee
2013-01-01
Cardiac arrhythmias are a leading cause of death worldwide. Notably, the electrophysiologiy and microstructural requirements for a fatal ventricular arrhythmia remain incompletely understood, thereby the treatment remains largely empirical. Standard antiarrhythmic drug therapy has failed to reduce, and in some instances has increased, the incidence of Sudden Cardiac Death (SCD). Hence, a more complete understanding of the mechanisms that foment a fatal arrhythmia is needed and computational m...
Uncertainty in biology: a computational modeling approach
2015-01-01
Computational modeling of biomedical processes is gaining more and more weight in the current research into the etiology of biomedical problems and potential treatment strategies. Computational modeling allows to reduce, refine and replace animal experimentation as well as to translate findings obtained in these experiments to the human background. However these biomedical problems are inherently complex with a myriad of influencing factors, which strongly complicates the model building...
Creation of 'Ukrytie' objects computer model
International Nuclear Information System (INIS)
A partial computer model of the 'Ukrytie' object was created with the use of geoinformation technologies. The computer model makes it possible to carry out information support of the works related to the 'Ukrytie' object stabilization and its conversion into ecologically safe system for analyzing, forecasting and controlling the processes occurring in the 'Ukrytie' object. Elements and structures of the 'Ukryttia' object were designed and input into the model
Introducing Seismic Tomography with Computational Modeling
Neves, R.; Neves, M. L.; Teodoro, V.
2011-12-01
Learning seismic tomography principles and techniques involves advanced physical and computational knowledge. In depth learning of such computational skills is a difficult cognitive process that requires a strong background in physics, mathematics and computer programming. The corresponding learning environments and pedagogic methodologies should then involve sets of computational modelling activities with computer software systems which allow students the possibility to improve their mathematical or programming knowledge and simultaneously focus on the learning of seismic wave propagation and inverse theory. To reduce the level of cognitive opacity associated with mathematical or programming knowledge, several computer modelling systems have already been developed (Neves & Teodoro, 2010). Among such systems, Modellus is particularly well suited to achieve this goal because it is a domain general environment for explorative and expressive modelling with the following main advantages: 1) an easy and intuitive creation of mathematical models using just standard mathematical notation; 2) the simultaneous exploration of images, tables, graphs and object animations; 3) the attribution of mathematical properties expressed in the models to animated objects; and finally 4) the computation and display of mathematical quantities obtained from the analysis of images and graphs. Here we describe virtual simulations and educational exercises which enable students an easy grasp of the fundamental of seismic tomography. The simulations make the lecture more interactive and allow students the possibility to overcome their lack of advanced mathematical or programming knowledge and focus on the learning of seismological concepts and processes taking advantage of basic scientific computation methods and tools.
Directory of Open Access Journals (Sweden)
Meral Kelleci
2008-06-01
Full Text Available The use of digital technology, including computers, cell phones, computer games, and so on, most recently, on-the-go for recreational purposes, has increased among our youth over the past 15 years. Children and adolescent between the ages of 8 to 18 years spend an average of 5-6 hours per day using information and communication technologies. It is a useful progress because of the increase of internet usage which is unlimited, uncontrolled and uninhibited and easiness which arrival all sorts of to informations or persons but this state can cause to some important negative results too. The computer games, the internet explores is gradually estrange from social life the children and adolescent. In this paper, has been mentioned to negative effect of internet usage, computer games on mental health of children and adolescents. [TAF Prev Med Bull 2008; 7(3.000: 253-256
Uncertainty in biology a computational modeling approach
Gomez-Cabrero, David
2016-01-01
Computational modeling of biomedical processes is gaining more and more weight in the current research into the etiology of biomedical problems and potential treatment strategies. Computational modeling allows to reduce, refine and replace animal experimentation as well as to translate findings obtained in these experiments to the human background. However these biomedical problems are inherently complex with a myriad of influencing factors, which strongly complicates the model building and validation process. This book wants to address four main issues related to the building and validation of computational models of biomedical processes: Modeling establishment under uncertainty Model selection and parameter fitting Sensitivity analysis and model adaptation Model predictions under uncertainty In each of the abovementioned areas, the book discusses a number of key-techniques by means of a general theoretical description followed by one or more practical examples. This book is intended for graduate stude...
MODEL IDENTIFICATION AND COMPUTER ALGEBRA
Bollen, Kenneth A.; Bauldry, Shawn
2010-01-01
Multiequation models that contain observed or latent variables are common in the social sciences. To determine whether unique parameter values exist for such models, one needs to assess model identification. In practice analysts rely on empirical checks that evaluate the singularity of the information matrix evaluated at sample estimates of parameters. The discrepancy between estimates and population values, the limitations of numerical assessments of ranks, and the difference between local a...
Inna V. Petrova; Galina I. Efremova; Elena V. BELOVOL; Angelina A. Shagurova
2015-01-01
This paper is devoted to the problem of psychological addiction to video games. Features of influence of video games on the self-consciousness of adolescents are indicated. Distinctions between dependent behavior and a condition of preoccupation with video games are specified. Results of work which was carried out in Russia are designated. The purpose of the study was to investigate the influence of computer games on the “self-image” teenagers. 233 adolescents aged 13-15 years acted in qualit...
Notions of similarity for computational biology models
Waltemath, Dagmar
2016-03-21
Computational models used in biology are rapidly increasing in complexity, size, and numbers. To build such large models, researchers need to rely on software tools for model retrieval, model combination, and version control. These tools need to be able to quantify the differences and similarities between computational models. However, depending on the specific application, the notion of similarity may greatly vary. A general notion of model similarity, applicable to various types of models, is still missing. Here, we introduce a general notion of quantitative model similarities, survey the use of existing model comparison methods in model building and management, and discuss potential applications of model comparison. To frame model comparison as a general problem, we describe a theoretical approach to defining and computing similarities based on different model aspects. Potentially relevant aspects of a model comprise its references to biological entities, network structure, mathematical equations and parameters, and dynamic behaviour. Future similarity measures could combine these model aspects in flexible, problem-specific ways in order to mimic users\\' intuition about model similarity, and to support complex model searches in databases.
Predictive Models and Computational Embryology
EPA’s ‘virtual embryo’ project is building an integrative systems biology framework for predictive models of developmental toxicity. One schema involves a knowledge-driven adverse outcome pathway (AOP) framework utilizing information from public databases, standardized ontologies...
Savi Cakar, Firdevs; Karatas, Zeynep
2012-01-01
In this study, a developed model to explain a causal relationship between adolescent's self-esteem, perceived social support and hopelessness is tested. The purpose of the study is to explore the relationship between self-esteem, perceived social support and hopelessness in adolescents. A total of 257 adolescents, including 143 female and 114…
Parents as Role Models: Parental Behavior Affects Adolescents' Plans for Work Involvement
Wiese, Bettina S.; Freund, Alexandra M.
2011-01-01
This study (N = 520 high-school students) investigates the influence of parental work involvement on adolescents' own plans regarding their future work involvement. As expected, adolescents' perceptions of parental work behavior affected their plans for own work involvement. Same-sex parents served as main role models for the adolescents' own…
Computer Model Locates Environmental Hazards
2008-01-01
Catherine Huybrechts Burton founded San Francisco-based Endpoint Environmental (2E) LLC in 2005 while she was a student intern and project manager at Ames Research Center with NASA's DEVELOP program. The 2E team created the Tire Identification from Reflectance model, which algorithmically processes satellite images using turnkey technology to retain only the darkest parts of an image. This model allows 2E to locate piles of rubber tires, which often are stockpiled illegally and cause hazardous environmental conditions and fires.
COSP - A computer model of cyclic oxidation
Lowell, Carl E.; Barrett, Charles A.; Palmer, Raymond W.; Auping, Judith V.; Probst, Hubert B.
1991-01-01
A computer model useful in predicting the cyclic oxidation behavior of alloys is presented. The model considers the oxygen uptake due to scale formation during the heating cycle and the loss of oxide due to spalling during the cooling cycle. The balance between scale formation and scale loss is modeled and used to predict weight change and metal loss kinetics. A simple uniform spalling model is compared to a more complex random spall site model. In nearly all cases, the simpler uniform spall model gave predictions as accurate as the more complex model. The model has been applied to several nickel-base alloys which, depending upon composition, form Al2O3 or Cr2O3 during oxidation. The model has been validated by several experimental approaches. Versions of the model that run on a personal computer are available.
Computational Models for Nonlinear Aeroelastic Systems Project
National Aeronautics and Space Administration — Clear Science Corp. and Duke University propose to develop and demonstrate a new and efficient computational method of modeling nonlinear aeroelastic systems. The...
Computational models for analyzing lipoprotein profiles
Graaf, A.A. de; Schalkwijk, D.B. van
2011-01-01
At present, several measurement technologies are available for generating highly detailed concentration-size profiles of lipoproteins, offering increased diagnostic potential. Computational models are useful in aiding the interpretation of these complex datasets and making the data more accessible f
A new epidemic model of computer viruses
Yang, Lu-Xing; Yang, Xiaofan
2014-06-01
This paper addresses the epidemiological modeling of computer viruses. By incorporating the effect of removable storage media, considering the possibility of connecting infected computers to the Internet, and removing the conservative restriction on the total number of computers connected to the Internet, a new epidemic model is proposed. Unlike most previous models, the proposed model has no virus-free equilibrium and has a unique endemic equilibrium. With the aid of the theory of asymptotically autonomous systems as well as the generalized Poincare-Bendixson theorem, the endemic equilibrium is shown to be globally asymptotically stable. By analyzing the influence of different system parameters on the steady number of infected computers, a collection of policies is recommended to prohibit the virus prevalence.
Computer simulations of the random barrier model
DEFF Research Database (Denmark)
Schrøder, Thomas; Dyre, Jeppe
2002-01-01
A brief review of experimental facts regarding ac electronic and ionic conduction in disordered solids is given followed by a discussion of what is perhaps the simplest realistic model, the random barrier model (symmetric hopping model). Results from large scale computer simulations are presented...
Efficient sampling and meta-modeling in computational economic models
I. Salle; M. Yıldızoğlu
2014-01-01
Extensive exploration of simulation models comes at a high computational cost, all the more when the model involves a lot of parameters. Economists usually rely on random explorations, such as Monte Carlo simulations, and basic econometric modeling to approximate the properties of computational mode
The ATLAS computing model and distributed computing evolution
Jones, Roger W L
2009-01-01
Despite only a brief availability of beam-related data, the typical usage patterns and operational requirements of the ATLAS computing model have been exercised, and the model as originally constructed remains remarkably unchanged. Resource requirements have been revised, and cosmic ray running has exercised much of the model in both duration and volume. The operational model has been adapted in several ways to increase performance and meet the asdelivered functionality of the available middleware. There are also changes reflecting the emerging roles of the different data formats. The model continues to evolve with a heightened focus on end-user performance, the key tools developed in the operational system are outlined, with an emphasis on those under recent development.
Jorge Delva; Liyun Wu
2012-01-01
We used longitudinal data to investigate the relationship between computer use in internet cafés and smoking/drinking behavior among Chinese adolescents and young adults. Data are from two waves of the China Health and Nutrition Survey (2004 and 2006). Fixed effects models were used to examine if changes in internet café use were associated with changes in cigarette smoking and drinking of alcohol. Male café users spent on average 17.3 hours in front of the computer/week. This was associated ...
Etiological model of disordered eating behaviors in Brazilian adolescent girls.
Fortes, Leonardo de Sousa; Filgueiras, Juliana Fernandes; Oliveira, Fernanda da Costa; Almeida, Sebastião Sousa; Ferreira, Maria Elisa Caputo
2016-01-01
The objective was to construct an etiological model of disordered eating behaviors in Brazilian adolescent girls. A total of 1,358 adolescent girls from four cities participated. The study used psychometric scales to assess disordered eating behaviors, body dissatisfaction, media pressure, self-esteem, mood, depressive symptoms, and perfectionism. Weight, height, and skinfolds were measured to calculate body mass index (BMI) and percent body fat (%F). Structural equation modeling explained 76% of variance in disordered eating behaviors (F(9, 1,351) = 74.50; p = 0.001). The findings indicate that body dissatisfaction mediated the relationship between media pressures, self-esteem, mood, BMI, %F, and disordered eating behaviors (F(9, 1,351) = 59.89; p = 0.001). Although depressive symptoms were not related to body dissatisfaction, the model indicated a direct relationship with disordered eating behaviors (F(2, 1,356) = 23.98; p = 0.001). In conclusion, only perfectionism failed to fit the etiological model of disordered eating behaviors in Brazilian adolescent girls. PMID:27167040
A Computational Framework for Realistic Retina Modeling.
Martínez-Cañada, Pablo; Morillas, Christian; Pino, Begoña; Ros, Eduardo; Pelayo, Francisco
2016-11-01
Computational simulations of the retina have led to valuable insights about the biophysics of its neuronal activity and processing principles. A great number of retina models have been proposed to reproduce the behavioral diversity of the different visual processing pathways. While many of these models share common computational stages, previous efforts have been more focused on fitting specific retina functions rather than generalizing them beyond a particular model. Here, we define a set of computational retinal microcircuits that can be used as basic building blocks for the modeling of different retina mechanisms. To validate the hypothesis that similar processing structures may be repeatedly found in different retina functions, we implemented a series of retina models simply by combining these computational retinal microcircuits. Accuracy of the retina models for capturing neural behavior was assessed by fitting published electrophysiological recordings that characterize some of the best-known phenomena observed in the retina: adaptation to the mean light intensity and temporal contrast, and differential motion sensitivity. The retinal microcircuits are part of a new software platform for efficient computational retina modeling from single-cell to large-scale levels. It includes an interface with spiking neural networks that allows simulation of the spiking response of ganglion cells and integration with models of higher visual areas. PMID:27354192
Computational Modeling of Culture's Consequences
Hofstede, G.J.; Jonker, C.M.; Verwaart, T.
2010-01-01
This paper presents an approach to formalize the influence of culture on the decision functions of agents in social simulations. The key components are (a) a definition of the domain of study in the form of a decision model, (b) knowledge acquisition based on a dimensional theory of culture, resulti
Computational aspects of premixing modelling
Energy Technology Data Exchange (ETDEWEB)
Fletcher, D.F. [Sydney Univ., NSW (Australia). Dept. of Chemical Engineering; Witt, P.J.
1998-01-01
In the steam explosion research field there is currently considerable effort being devoted to the modelling of premixing. Practically all models are based on the multiphase flow equations which treat the mixture as an interpenetrating continuum. Solution of these equations is non-trivial and a wide range of solution procedures are in use. This paper addresses some numerical aspects of this problem. In particular, we examine the effect of the differencing scheme for the convective terms and show that use of hybrid differencing can cause qualitatively wrong solutions in some situations. Calculations are performed for the Oxford tests, the BNL tests, a MAGICO test and to investigate various sensitivities of the solution. In addition, we show that use of a staggered grid can result in a significant error which leads to poor predictions of `melt` front motion. A correction is given which leads to excellent convergence to the analytic solution. Finally, we discuss the issues facing premixing model developers and highlight the fact that model validation is hampered more by the complexity of the process than by numerical issues. (author)
Computer-Aided Modelling Methods and Tools
DEFF Research Database (Denmark)
Cameron, Ian; Gani, Rafiqul
2011-01-01
The development of models for a range of applications requires methods and tools. In many cases a reference model is required that allows the generation of application specific models that are fit for purpose. There are a range of computer aided modelling tools available that help to define....... To illustrate these concepts a number of examples are used. These include models of polymer membranes, distillation and catalyst behaviour. Some detailed considerations within these models are stated and discussed. Model generation concepts are introduced and ideas of a reference model are given that shows...... a taxonomy of aspects around conservation, constraints and constitutive relations. Aspects of the ICAS-MoT toolbox are given to illustrate the functionality of a computer aided modelling tool, which incorporates an interface to MS Excel....
Computer Modeling of Direct Metal Laser Sintering
Cross, Matthew
2014-01-01
A computational approach to modeling direct metal laser sintering (DMLS) additive manufacturing process is presented. The primary application of the model is for determining the temperature history of parts fabricated using DMLS to evaluate residual stresses found in finished pieces and to assess manufacturing process strategies to reduce part slumping. The model utilizes MSC SINDA as a heat transfer solver with imbedded FORTRAN computer code to direct laser motion, apply laser heating as a boundary condition, and simulate the addition of metal powder layers during part fabrication. Model results are compared to available data collected during in situ DMLS part manufacture.
The IceCube Computing Infrastructure Model
International Nuclear Information System (INIS)
In addition to the big LHC experiments, a number of mid-size experiments are coming online which need to define new computing models to meet the demands on processing and storage requirements of those experiments. We present the hybrid computing model of IceCube which leverages Grid models with a more flexible direct user model as an example of a possible solution. In IceCube a central data center at UW-Madison serves as a Tier-0 with a single Tier-1 at DESY Zeuthen.
Adolescent Contraceptive Use: Models, Research, and Directions.
Whitley, Bernard E., Jr.; Schofield, Janet Ward
Both the career model and the decision model have been proposed to explain patterns of contraceptive use in teenagers. The career model views contraceptive use as a symbol of a woman's sexuality and implies a clear decision to be sexually active. The decision model is based on the subjective expected utility (SEU) theory which holds that people…
CLOUD COMPUTING SECURITY THROUGH SYMMETRIC CIPHER MODEL
Directory of Open Access Journals (Sweden)
Subramanian Anbazhagan
2014-10-01
Full Text Available Cloud computing can be defined as an application and services which runs on distributed network using virtualized and it is accessed through internet protocols and networking. Cloud computing resources and virtual and limitless and information’s of the physical systems on which software running are abstracted from the user. Cloud Computing is a style of computing in which dynamically scalable and often virtualized resources are provided as a service over the Internet. Users need not have knowledge of, expertise in, or control over the technology infrastructure in the "cloud" that supports them. To satisfy the needs of the users the concept is to incorporate technologies which have the common theme of reliance on the internet Software and data are stored on the servers whereas cloud computing services are provided through applications online which can be accessed from web browsers. Lack of security and access control is the major drawback in the cloud computing as the users deal with sensitive data to public clouds .Multiple virtual machine in cloud can access insecure information flows as service provider; therefore to implement the cloud it is necessary to build security. Therefore the main aim of this paper is to provide cloud computing security through symmetric cipher model. This article proposes symmetric cipher model in order to implement cloud computing security so that data can accessed and stored securely.
Chen, Mei-Yen; Liou, Yiing-Mei; Wu, Jen-Yee
2008-03-01
Television and computers provide significant benefits for learning about the world. Some studies have linked excessive television (TV) watching or computer game playing to disadvantage of health status or some unhealthy behavior among adolescents. However, the relationships between watching TV/playing computer games and adolescents adopting health promoting behavior were limited. This study aimed to discover the relationship between time spent on watching TV and on leisure use of computers and adolescents' health promoting behavior, and associated factors. This paper used secondary data analysis from part of a health promotion project in Taoyuan County, Taiwan. A cross-sectional design was used and purposive sampling was conducted among adolescents in the original project. A total of 660 participants answered the questions appropriately for this work between January and June 2004. Findings showed the mean age of the respondents was 15.0 +/- 1.7 years. The mean numbers of TV watching hours were 2.28 and 4.07 on weekdays and weekends respectively. The mean hours of leisure (non-academic) computer use were 1.64 and 3.38 on weekdays and weekends respectively. Results indicated that adolescents spent significant time watching TV and using the computer, which was negatively associated with adopting health-promoting behaviors such as life appreciation, health responsibility, social support and exercise behavior. Moreover, being boys, being overweight, living in a rural area, and being middle-school students were significantly associated with spending long periods watching TV and using the computer. Therefore, primary health care providers should record the TV and non-academic computer time of youths when conducting health promotion programs, and educate parents on how to become good and healthy electronic media users. PMID:18348110
Energy Technology Data Exchange (ETDEWEB)
Lee, Choonsik; Kim, Kwang Pyo; Long, Daniel J.; Bolch, Wesley E. [Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institute of Health, Bethesda, Maryland 20852 (United States); Department of Nuclear Engineering, Kyung Hee University, Gyeonggi-do, 446906 (Korea, Republic of); J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida 32611 (United States)
2012-04-15
Purpose: To establish an organ dose database for pediatric and adolescent reference individuals undergoing computed tomography (CT) examinations by using Monte Carlo simulation. The data will permit rapid estimates of organ and effective doses for patients of different age, gender, examination type, and CT scanner model. Methods: The Monte Carlo simulation model of a Siemens Sensation 16 CT scanner previously published was employed as a base CT scanner model. A set of absorbed doses for 33 organs/tissues normalized to the product of 100 mAs and CTDI{sub vol} (mGy/100 mAs mGy) was established by coupling the CT scanner model with age-dependent reference pediatric hybrid phantoms. A series of single axial scans from the top of head to the feet of the phantoms was performed at a slice thickness of 10 mm, and at tube potentials of 80, 100, and 120 kVp. Using the established CTDI{sub vol}- and 100 mAs-normalized dose matrix, organ doses for different pediatric phantoms undergoing head, chest, abdomen-pelvis, and chest-abdomen-pelvis (CAP) scans with the Siemens Sensation 16 scanner were estimated and analyzed. The results were then compared with the values obtained from three independent published methods: CT-Expo software, organ dose for abdominal CT scan derived empirically from patient abdominal circumference, and effective dose per dose-length product (DLP). Results: Organ and effective doses were calculated and normalized to 100 mAs and CTDI{sub vol} for different CT examinations. At the same technical setting, dose to the organs, which were entirely included in the CT beam coverage, were higher by from 40 to 80% for newborn phantoms compared to those of 15-year phantoms. An increase of tube potential from 80 to 120 kVp resulted in 2.5-2.9-fold greater brain dose for head scans. The results from this study were compared with three different published studies and/or techniques. First, organ doses were compared to those given by CT-Expo which revealed dose
A computational model of the cerebellum
Energy Technology Data Exchange (ETDEWEB)
Travis, B.J.
1990-01-01
The need for realistic computational models of neural microarchitecture is growing increasingly apparent. While traditional neural networks have made inroads on understanding cognitive functions, more realism (in the form of structural and connectivity constraints) is required to explain processes such as vision or motor control. A highly detailed computational model of mammalian cerebellum has been developed. It is being compared to physiological recordings for validation purposes. The model is also being used to study the relative contributions of each component to cerebellar processing. 28 refs., 4 figs.
Mechanistic Models in Computational Social Science
Holme, Petter
2015-01-01
Quantitative social science is not only about regression analysis or, in general, data inference. Computer simulations of social mechanisms have an over 60 years long history. They have been used for many different purposes -- to test scenarios, to test the consistency of descriptive theories (proof-of-concept models), to explore emerging phenomena, for forecasting, etc. In this essay, we sketch these historical developments, the role of mechanistic models in the social sciences and the influences from natural and formal sciences. We argue that mechanistic computational models form a natural common ground for social and natural sciences, and look forward to possible future information flow across the social-natural divide.
Computational modeling of failure in composite laminates
Van der Meer, F.P.
2010-01-01
There is no state of the art computational model that is good enough for predictive simulation of the complete failure process in laminates. Already on the single ply level controversy exists. Much work has been done in recent years in the development of continuum models, but these fail to predict t
Computational Intelligence. Mortality Models for the Actuary
Willemse, W.J.
2001-01-01
This thesis applies computational intelligence to the field of actuarial (insurance) science. In particular, this thesis deals with life insurance where mortality modelling is important. Actuaries use ancient models (mortality laws) from the nineteenth century, for example Gompertz' and Makeham's la
Teaching Forest Planning with Computer Models
Howard, Richard A.; Magid, David
1977-01-01
This paper describes a series of FORTRAN IV computer models which are the content-oriented subject matter for a college course in forest planning. The course objectives, the planning problem, and the ten planning aid models are listed. Student comments and evaluation of the program are included. (BT)
Human systems dynamics: Toward a computational model
Eoyang, Glenda H.
2012-09-01
A robust and reliable computational model of complex human systems dynamics could support advancements in theory and practice for social systems at all levels, from intrapersonal experience to global politics and economics. Models of human interactions have evolved from traditional, Newtonian systems assumptions, which served a variety of practical and theoretical needs of the past. Another class of models has been inspired and informed by models and methods from nonlinear dynamics, chaos, and complexity science. None of the existing models, however, is able to represent the open, high dimension, and nonlinear self-organizing dynamics of social systems. An effective model will represent interactions at multiple levels to generate emergent patterns of social and political life of individuals and groups. Existing models and modeling methods are considered and assessed against characteristic pattern-forming processes in observed and experienced phenomena of human systems. A conceptual model, CDE Model, based on the conditions for self-organizing in human systems, is explored as an alternative to existing models and methods. While the new model overcomes the limitations of previous models, it also provides an explanatory base and foundation for prospective analysis to inform real-time meaning making and action taking in response to complex conditions in the real world. An invitation is extended to readers to engage in developing a computational model that incorporates the assumptions, meta-variables, and relationships of this open, high dimension, and nonlinear conceptual model of the complex dynamics of human systems.
On the completeness of quantum computation models
Arrighi, Pablo
2010-01-01
The notion of computability is stable (i.e. independent of the choice of an indexing) over infinite-dimensional vector spaces provided they have a finite "tensorial dimension". Such vector spaces with a finite tensorial dimension permit to define an absolute notion of completeness for quantum computation models and give a precise meaning to the Church-Turing thesis in the framework of quantum theory. (Extra keywords: quantum programming languages, denotational semantics, universality.)
Computer modelling of tornado effects on buildings
International Nuclear Information System (INIS)
An attempt is made to model the tornado-structure interaction. The tornado is represented as a Rankine-Combined vortex. The computations are done on a rectangular grid system. The governing equations are approximated using control volume procedure. The pressure equations are solved by an efficient preconditioned conjugate gradient procedure. The computed tornado forces are compared with straight boundary layer (SBL) wind. The tornado forces on the roof of the building is more than five times the SBL flow
Parallel Computing Applications and Financial Modelling
Liddell, Heather M.; Parkinson, D.; Hodgson, G S; Dzwig, P.
2004-01-01
At Queen Mary, University of London, we have over twenty years of experience in Parallel Computing Applications, mostly on "massively parallel systems", such as the Distributed Array Processors (DAPs). The applications in which we were involved included design of numerical subroutine libraries, Finite Element software, graphics tools, the physics of organic materials, medical imaging, computer vision and more recently, Financial modelling. Two of the projects related to the latter are describ...
Parallel Computing of Ocean General Circulation Model
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
This paper discusses the parallel computing of the thirdgeneration Ocea n General Circulation Model (OGCM) from the State Key Laboratory of Numerical Mo deling for Atmospheric Science and Geophysical Fluid Dynamics(LASG),Institute of Atmosphere Physics(IAP). Meanwhile, several optimization strategies for paralle l computing of OGCM (POGCM) on Scalable Shared Memory Multiprocessor (S2MP) are presented. Using Message Passing Interface (MPI), we obtain super linear speedup on SGI Origin 2000 for parallel OGCM(POGCM) after optimization.
A Classical Probabilistic Computer Model of Consciousness
Blaha, Stephen
2002-01-01
We show that human consciousness can be modeled as a classical (not quantum) probabilistic computer. A quantum computer representation does not appear to be indicated because no known feature of consciousness depends on Planck's constant h, the telltale sign of quantum phenomena. It is argued that the facets of consciousness are describable by an object-oriented design with dynamically defined classes and objects. A comparison to economic theory is also made. We argue consciousness may also h...
Finite difference computing with exponential decay models
Langtangen, Hans Petter
2016-01-01
This text provides a very simple, initial introduction to the complete scientific computing pipeline: models, discretization, algorithms, programming, verification, and visualization. The pedagogical strategy is to use one case study – an ordinary differential equation describing exponential decay processes – to illustrate fundamental concepts in mathematics and computer science. The book is easy to read and only requires a command of one-variable calculus and some very basic knowledge about computer programming. Contrary to similar texts on numerical methods and programming, this text has a much stronger focus on implementation and teaches testing and software engineering in particular. .
A computational model of analogical reasoning
Institute of Scientific and Technical Information of China (English)
李波; 赵沁平
1997-01-01
A computational model of analogical reasoning is presented, which divides analogical reasoning process into four subprocesses, i.e. reminding, elaboration, matching and transfer. For each subprocess, its role and the principles it follows are given. The model is discussed in detail, including salient feature-based reminding, relevance-directed elaboration, an improved matching model and a transfer model. And the advantages of this model are summarized based on the results of BHARS, which is an analogical reasoning system implemented by this model.
A Categorisation of Cloud Computing Business Models
Chang, Victor; Bacigalupo, David; Wills, Gary; De Roure, David
2010-01-01
This paper reviews current cloud computing business models and presents proposals on how organisations can achieve sustainability by adopting appropriate models. We classify cloudcomputing business models into eight types: (1) Service Provider and Service Orientation; (2) Support and Services Contracts; (3) In-House Private Clouds; (4) All-In-One Enterprise Cloud; (5) One-Stop Resources and Services; (6) Government Funding; (7) Venture Capitals; and (8) Entertainment and Social Networking. Us...
Computational disease modeling – fact or fiction?
Directory of Open Access Journals (Sweden)
Stephan Klaas
2009-06-01
Full Text Available Abstract Background Biomedical research is changing due to the rapid accumulation of experimental data at an unprecedented scale, revealing increasing degrees of complexity of biological processes. Life Sciences are facing a transition from a descriptive to a mechanistic approach that reveals principles of cells, cellular networks, organs, and their interactions across several spatial and temporal scales. There are two conceptual traditions in biological computational-modeling. The bottom-up approach emphasizes complex intracellular molecular models and is well represented within the systems biology community. On the other hand, the physics-inspired top-down modeling strategy identifies and selects features of (presumably essential relevance to the phenomena of interest and combines available data in models of modest complexity. Results The workshop, "ESF Exploratory Workshop on Computational disease Modeling", examined the challenges that computational modeling faces in contributing to the understanding and treatment of complex multi-factorial diseases. Participants at the meeting agreed on two general conclusions. First, we identified the critical importance of developing analytical tools for dealing with model and parameter uncertainty. Second, the development of predictive hierarchical models spanning several scales beyond intracellular molecular networks was identified as a major objective. This contrasts with the current focus within the systems biology community on complex molecular modeling. Conclusion During the workshop it became obvious that diverse scientific modeling cultures (from computational neuroscience, theory, data-driven machine-learning approaches, agent-based modeling, network modeling and stochastic-molecular simulations would benefit from intense cross-talk on shared theoretical issues in order to make progress on clinically relevant problems.
Computer-Aided Business Model Design
Fritscher B.
2014-01-01
There is a lack of dedicated tools for business model design at a strategic level. However, in today's economic world the need to be able to quickly reinvent a company's business model is essential to stay competitive. This research focused on identifying the functionalities that are necessary in a computer-aided design (CAD) tool for the design of business models in a strategic context. Using design science research methodology a series of techniques and prototypes have been designed and eva...
Generating computational models for serious gaming
Westera, Wim
2013-01-01
Many serious games include computational models that simulate dynamic systems. These models promote enhanced interaction and responsiveness. Under the social web paradigm more and more usable game authoring tools become available that enable prosumers to create their own games, but the inclusion of dynamic simulations remains a specialist’s job involving knowledge of mathematics, numerical modeling and programming. This paper describes a methodology for specifying and running a specific subse...
Clark, Stephen Allan
The impact of technology (including computers and probes, low friction carts, video camera, VCR's and electronic balances) on the motivation of adolescent science students was investigated using a naturalistic case study of college preparatory ninth grade physics classes at a comprehensive high school in the southeastern United States. The students were positively affected by the use of computer technology as compared to other "low tech" labs. The non-computer technologies had little motivational effect on the students. The most important motivational effect was the belief among the students that they could successfully operate the equipment and gather meaningful results. At times, the students spent more cognitive energy on performing the experiment than on learning the physics. This was especially true when microcomputer-based labs were used. When the technology led to results that were clear to the students and displayed in a manner that could be easily interpreted, they were generally receptive and motivated to persist at the task. Many students reported being especially motivated when a computer was used to gather the data because they "just liked computers." Furthermore, qualitative evidence suggested that they had learned the physics concept they were working on. This is in close agreement with the conceptual change model of learning in that students are most likely to change their prior conceptions when the new idea is plausible (the technology makes it so), intelligible (real time graphing, actual light rays), and fruitful (the new idea explains what they actually see). However, many of the microcomputer-based laboratory (MBL) activities and "high tech" labs were too unstructured, leaving students bewildered, confused and unmotivated. To achieve maximum motivational effects from the technology, it was necessary to reduce the cognitive demand on the students so they could concentrate on the data gathered rather than the operation of the equipment.
Solving stochastic epidemiological models using computer algebra
Hincapie, Doracelly; Ospina, Juan
2011-06-01
Mathematical modeling in Epidemiology is an important tool to understand the ways under which the diseases are transmitted and controlled. The mathematical modeling can be implemented via deterministic or stochastic models. Deterministic models are based on short systems of non-linear ordinary differential equations and the stochastic models are based on very large systems of linear differential equations. Deterministic models admit complete, rigorous and automatic analysis of stability both local and global from which is possible to derive the algebraic expressions for the basic reproductive number and the corresponding epidemic thresholds using computer algebra software. Stochastic models are more difficult to treat and the analysis of their properties requires complicated considerations in statistical mathematics. In this work we propose to use computer algebra software with the aim to solve epidemic stochastic models such as the SIR model and the carrier-borne model. Specifically we use Maple to solve these stochastic models in the case of small groups and we obtain results that do not appear in standard textbooks or in the books updated on stochastic models in epidemiology. From our results we derive expressions which coincide with those obtained in the classical texts using advanced procedures in mathematical statistics. Our algorithms can be extended for other stochastic models in epidemiology and this shows the power of computer algebra software not only for analysis of deterministic models but also for the analysis of stochastic models. We also perform numerical simulations with our algebraic results and we made estimations for the basic parameters as the basic reproductive rate and the stochastic threshold theorem. We claim that our algorithms and results are important tools to control the diseases in a globalized world.
Sitnick, Stephanie; Shaw, Daniel S.; Hyde, Luke
2013-01-01
This study examined developmentally-salient risk and protective factors of adolescent substance use assessed during early childhood and early adolescence using a sample of 310 low-income boys. Child problem behavior and proximal family risk and protective factors (i.e., parenting, maternal depression) during early childhood, as well as child and family factors and peer deviant behavior during adolescence were explored as potential precursors to later substance use during adolescence using str...
Computer Aided Modelling – Opportunities and Challenges
DEFF Research Database (Denmark)
Cameron, Ian; Gani, Rafiqul
2011-01-01
This chapter considers the opportunities that are present in developing, extending and applying aspects of computer-aided modelling principles and practice. What are the best tasks to be done by modellers and what needs the application of CAPE tools? How do we efficiently develop model-based...... solutions to significant problems? The important issues of workflow and data flow are discussed together with fit-for-purpose model development. As well, the lack of tools around multiscale modelling provides opportunities for the development of efficient tools to address such challenges. The ability...
Computational modeling of laser-tissue interaction
Energy Technology Data Exchange (ETDEWEB)
London, R.A.; Amendt, P.; Bailey, D.S.; Eder, D.C.; Maitland, D.J.; Glinsky, M.E.; Strauss, M.; Zimmerman, G.B.
1996-05-01
Computational modeling can play an important role both in designing laser-tissue interaction experiments and in understanding the underlying mechanisms. This can lead to more rapid and less expensive development if new procedures and instruments, and a better understanding of their operation. We have recently directed computer programs and associated expertise developed over many years to model high intensity laser-matter interactions for fusion research towards laser-tissue interaction problem. A program called LATIS is being developed to specifically treat laser-tissue interaction phenomena, such as highly scattering light transport, thermal coagulation, and hydrodynamic motion.
Computational algebraic geometry of epidemic models
Rodríguez Vega, Martín.
2014-06-01
Computational Algebraic Geometry is applied to the analysis of various epidemic models for Schistosomiasis and Dengue, both, for the case without control measures and for the case where control measures are applied. The models were analyzed using the mathematical software Maple. Explicitly the analysis is performed using Groebner basis, Hilbert dimension and Hilbert polynomials. These computational tools are included automatically in Maple. Each of these models is represented by a system of ordinary differential equations, and for each model the basic reproductive number (R0) is calculated. The effects of the control measures are observed by the changes in the algebraic structure of R0, the changes in Groebner basis, the changes in Hilbert dimension, and the changes in Hilbert polynomials. It is hoped that the results obtained in this paper become of importance for designing control measures against the epidemic diseases described. For future researches it is proposed the use of algebraic epidemiology to analyze models for airborne and waterborne diseases.
Biomedical Imaging and Computational Modeling in Biomechanics
Iacoviello, Daniela
2013-01-01
This book collects the state-of-art and new trends in image analysis and biomechanics. It covers a wide field of scientific and cultural topics, ranging from remodeling of bone tissue under the mechanical stimulus up to optimizing the performance of sports equipment, through the patient-specific modeling in orthopedics, microtomography and its application in oral and implant research, computational modeling in the field of hip prostheses, image based model development and analysis of the human knee joint, kinematics of the hip joint, micro-scale analysis of compositional and mechanical properties of dentin, automated techniques for cervical cell image analysis, and iomedical imaging and computational modeling in cardiovascular disease. The book will be of interest to researchers, Ph.D students, and graduate students with multidisciplinary interests related to image analysis and understanding, medical imaging, biomechanics, simulation and modeling, experimental analysis.
McCormick, Cheryl M; Travis E. Hodges; Jonathan J. Simone
2015-01-01
Studies in animal models generate and test hypotheses regarding developmental stage-specific vulnerability that might inform research questions about human development. In both rats and humans, peer relationships are qualitatively different in adolescence than at other stages of development, and social experiences in adolescence are considered important determinants of adult social function. This review describes our adolescent rat social instability stress model and the long-lasting effects ...
Directory of Open Access Journals (Sweden)
Tomasz Srebnicki
2016-06-01
Full Text Available First applications of computer-assisted technologies (CAT in the rehabilitation of cognitive deficits, including child and adolescent psychiatric disorders date back to the 80’s last century. Recent developments in computer technologies, wide access to the Internet and vast expansion of electronic devices resulted in dynamic increase in therapeutic software as well as supporting devices. The aim of computer assisted technologies is the improvement in the comfort and quality of life as well as the rehabilitation of impaired functions. The goal of the article is the presentation of most common computer-assisted technologies used in the therapy of children and adolescents with cognitive deficits as well as the literature review of their effectiveness including the challenges and limitations in regard to the implementation of such interventions.
Computer-aided modeling framework – a generic modeling template
DEFF Research Database (Denmark)
Fedorova, Marina; Sin, Gürkan; Gani, Rafiqul
This work focuses on the development of a computer-aided modeling framework. The framework is a knowledge-based system that is built on a generic modeling language and structured on workflows for different modeling tasks. The overall objective is to support model developers and users to generate ....... The application of the modeling template is highlighted with a case study related to the modeling of a catalytic membrane reactor coupling dehydrogenation of ethylbenzene with hydrogenation of nitrobenzene...
Applied Mathematics, Modelling and Computational Science
Kotsireas, Ilias; Makarov, Roman; Melnik, Roderick; Shodiev, Hasan
2015-01-01
The Applied Mathematics, Modelling, and Computational Science (AMMCS) conference aims to promote interdisciplinary research and collaboration. The contributions in this volume cover the latest research in mathematical and computational sciences, modeling, and simulation as well as their applications in natural and social sciences, engineering and technology, industry, and finance. The 2013 conference, the second in a series of AMMCS meetings, was held August 26–30 and organized in cooperation with AIMS and SIAM, with support from the Fields Institute in Toronto, and Wilfrid Laurier University. There were many young scientists at AMMCS-2013, both as presenters and as organizers. This proceedings contains refereed papers contributed by the participants of the AMMCS-2013 after the conference. This volume is suitable for researchers and graduate students, mathematicians and engineers, industrialists, and anyone who would like to delve into the interdisciplinary research of applied and computational mathematics ...
High performance computing and numerical modelling
,
2014-01-01
Numerical methods play an ever more important role in astrophysics. This is especially true in theoretical works, but of course, even in purely observational projects, data analysis without massive use of computational methods has become unthinkable. The key utility of computer simulations comes from their ability to solve complex systems of equations that are either intractable with analytic techniques or only amenable to highly approximative treatments. Simulations are best viewed as a powerful complement to analytic reasoning, and as the method of choice to model systems that feature enormous physical complexity such as star formation in evolving galaxies, the topic of this 43rd Saas Fee Advanced Course. The organizers asked me to lecture about high performance computing and numerical modelling in this winter school, and to specifically cover the basics of numerically treating gravity and hydrodynamics in the context of galaxy evolution. This is still a vast field, and I necessarily had to select a subset ...
Garmy, Pernilla; Clausson, Eva K.; Nyberg, Per; Jakobsson, Ulf
2013-01-01
The aim of this cross-sectional study was to investigate the prevalence of overweight and obesity in children and adolescents (6–16 years), and relationships between being overweight and sleep, experiencing of fatigue, enjoyment of school, and time spent in watching television and in sitting at the computer. Trained school nurses measured the weight and height of 2891 children aged 6, 7, 10, 14, and 16, and distributed a questionnaire to them regarding television and computer habits, sleep, a...
Integrating interactive computational modeling in biology curricula.
Directory of Open Access Journals (Sweden)
Tomáš Helikar
2015-03-01
Full Text Available While the use of computer tools to simulate complex processes such as computer circuits is normal practice in fields like engineering, the majority of life sciences/biological sciences courses continue to rely on the traditional textbook and memorization approach. To address this issue, we explored the use of the Cell Collective platform as a novel, interactive, and evolving pedagogical tool to foster student engagement, creativity, and higher-level thinking. Cell Collective is a Web-based platform used to create and simulate dynamical models of various biological processes. Students can create models of cells, diseases, or pathways themselves or explore existing models. This technology was implemented in both undergraduate and graduate courses as a pilot study to determine the feasibility of such software at the university level. First, a new (In Silico Biology class was developed to enable students to learn biology by "building and breaking it" via computer models and their simulations. This class and technology also provide a non-intimidating way to incorporate mathematical and computational concepts into a class with students who have a limited mathematical background. Second, we used the technology to mediate the use of simulations and modeling modules as a learning tool for traditional biological concepts, such as T cell differentiation or cell cycle regulation, in existing biology courses. Results of this pilot application suggest that there is promise in the use of computational modeling and software tools such as Cell Collective to provide new teaching methods in biology and contribute to the implementation of the "Vision and Change" call to action in undergraduate biology education by providing a hands-on approach to biology.
Modeling Computations in a Semantic Network
Rodriguez, Marko A
2007-01-01
Semantic network research has seen a resurgence from its early history in the cognitive sciences with the inception of the Semantic Web initiative. The Semantic Web effort has brought forth an array of technologies that support the encoding, storage, and querying of the semantic network data structure at the world stage. Currently, the popular conception of the Semantic Web is that of a data modeling medium where real and conceptual entities are related in semantically meaningful ways. However, new models have emerged that explicitly encode procedural information within the semantic network substrate. With these new technologies, the Semantic Web has evolved from a data modeling medium to a computational medium. This article provides a classification of existing computational modeling efforts and the requirements of supporting technologies that will aid in the further growth of this burgeoning domain.
Modelling the effects of sexting on the transmission dynamics of HSV-2 amongst adolescents
Directory of Open Access Journals (Sweden)
A. Mhlanga
2015-12-01
Full Text Available Prior studies have indicated that adolescents who are into sexting are likely to engage in risky sexual behaviours. In this paper, a mathematical model to assess the impact of sexting and peer influence on the spread of HSV-2 amongst adolescents is developed. The threshold parameters of the model are determined and stabilities are analysed. The impact of filtering and awareness campaigns is explored. Results from the study suggest that HSV-2 prevalence is high amongst adolescents who are into sexting as compared to those who do not. Further, we applied optimal control theory to the proposed model. The controls represent filtering and awareness campaigns. The objective is based on minimising the susceptible sexting adolescents, infected non-sexting adolescents and the infected sexting adolescents. The optimal control is characterised and numerically solved. Overall, the application of optimal control theory suggests that more effort should be devoted to both controls, filtering and awareness campaigns.
Integer Programming Models for Computational Biology Problems
Institute of Scientific and Technical Information of China (English)
Giuseppe Lancia
2004-01-01
The recent years have seen an impressive increase in the use of Integer Programming models for the solution of optimization problems originating in Molecular Biology. In this survey, some of the most successful Integer Programming approaches are described, while a broad overview of application areas being is given in modern Computational Molecular Biology.
Images as a basis for computer modelling
Beaufils, D.; LeTouzé, J.-C.; Blondel, F.-M.
1994-03-01
New computer technologies such as the graphics data tablet, video digitization and numerical methods, can be used for measurement and mathematical modelling in physics. Two programs dealing with newtonian mechanics and some of related scientific activities for A-level students are described.
A Stochastic Dynamic Model of Computer Viruses
Directory of Open Access Journals (Sweden)
Chunming Zhang
2012-01-01
Full Text Available A stochastic computer virus spread model is proposed and its dynamic behavior is fully investigated. Specifically, we prove the existence and uniqueness of positive solutions, and the stability of the virus-free equilibrium and viral equilibrium by constructing Lyapunov functions and applying Ito's formula. Some numerical simulations are finally given to illustrate our main results.
A Multilayer Model of Computer Networks
Shchurov, Andrey A.
2015-01-01
The fundamental concept of applying the system methodology to network analysis declares that network architecture should take into account services and applications which this network provides and supports. This work introduces a formal model of computer networks on the basis of the hierarchical multilayer networks. In turn, individual layers are represented as multiplex networks. The concept of layered networks provides conditions of top-down consistency of the model. Next, we determined the...
Applied modelling and computing in social science
Povh, Janez
2015-01-01
In social science outstanding results are yielded by advanced simulation methods, based on state of the art software technologies and an appropriate combination of qualitative and quantitative methods. This book presents examples of successful applications of modelling and computing in social science: business and logistic process simulation and optimization, deeper knowledge extractions from big data, better understanding and predicting of social behaviour and modelling health and environment changes.
Automating sensitivity analysis of computer models using computer calculus
International Nuclear Information System (INIS)
An automated procedure for performing sensitivity analysis has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with direct and adjoint sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies
Automating sensitivity analysis of computer models using computer calculus
International Nuclear Information System (INIS)
An automated procedure for performing sensitivity analyses has been developed. The procedure uses a new FORTRAN compiler with computer calculus capabilities to generate the derivatives needed to set up sensitivity equations. The new compiler is called GRESS - Gradient Enhanced Software System. Application of the automated procedure with ''direct'' and ''adjoint'' sensitivity theory for the analysis of non-linear, iterative systems of equations is discussed. Calculational efficiency consideration and techniques for adjoint sensitivity analysis are emphasized. The new approach is found to preserve the traditional advantages of adjoint theory while removing the tedious human effort previously needed to apply this theoretical methodology. Conclusions are drawn about the applicability of the automated procedure in numerical analysis and large-scale modelling sensitivity studies. 24 refs., 2 figs
A Dualistic Model To Describe Computer Architectures
Nitezki, Peter; Engel, Michael
1985-07-01
The Dualistic Model for Computer Architecture Description uses a hierarchy of abstraction levels to describe a computer in arbitrary steps of refinement from the top of the user interface to the bottom of the gate level. In our Dualistic Model the description of an architecture may be divided into two major parts called "Concept" and "Realization". The Concept of an architecture on each level of the hierarchy is an Abstract Data Type that describes the functionality of the computer and an implementation of that data type relative to the data type of the next lower level of abstraction. The Realization on each level comprises a language describing the means of user interaction with the machine, and a processor interpreting this language in terms of the language of the lower level. The surface of each hierarchical level, the data type and the language express the behaviour of a ma-chine at this level, whereas the implementation and the processor describe the structure of the algorithms and the system. In this model the Principle of Operation maps the object and computational structure of the Concept onto the structures of the Realization. Describing a system in terms of the Dualistic Model is therefore a process of refinement starting at a mere description of behaviour and ending at a description of structure. This model has proven to be a very valuable tool in exploiting the parallelism in a problem and it is very transparent in discovering the points where par-allelism is lost in a special architecture. It has successfully been used in a project on a survey of Computer Architecture for Image Processing and Pattern Analysis in Germany.
Gema Mesquita; Rubens Reimão
2007-01-01
OBJECTIVE: To analyze the influence of nocturnal use of computer and their effect on sleep quality, in a group of adolescents. METHOD: Two middle schools were chosen for the research. The sample consisted of adolescents n=160 (55M; 105F), with ages ranging from 15 to 18 years. Questionnaire about computer use with the objective of obtaining information regarding the time and number of hours of nocturnal computer use, were applied for collection of data. They included the Pittsburgh Sleep Qual...
Parallel Computing Applications and Financial Modelling
Directory of Open Access Journals (Sweden)
Heather M. Liddell
2004-01-01
Full Text Available At Queen Mary, University of London, we have over twenty years of experience in Parallel Computing Applications, mostly on "massively parallel systems", such as the Distributed Array Processors (DAPs. The applications in which we were involved included design of numerical subroutine libraries, Finite Element software, graphics tools, the physics of organic materials, medical imaging, computer vision and more recently, Financial modelling. Two of the projects related to the latter are described in this paper, namely Portfolio Optimisation and Financial Risk Assessment.
Processor core model for quantum computing.
Yung, Man-Hong; Benjamin, Simon C; Bose, Sougato
2006-06-01
We describe an architecture based on a processing "core," where multiple qubits interact perpetually, and a separate "store," where qubits exist in isolation. Computation consists of single qubit operations, swaps between the store and the core, and free evolution of the core. This enables computation using physical systems where the entangling interactions are "always on." Alternatively, for switchable systems, our model constitutes a prescription for optimizing many-qubit gates. We discuss implementations of the quantum Fourier transform, Hamiltonian simulation, and quantum error correction.
Computer Aided Design Modeling for Heterogeneous Objects
Gupta, Vikas; Tandon, Puneet
2010-01-01
Heterogeneous object design is an active research area in recent years. The conventional CAD modeling approaches only provide geometry and topology of the object, but do not contain any information with regard to the materials of the object and so can not be used for the fabrication of heterogeneous objects (HO) through rapid prototyping. Current research focuses on computer-aided design issues in heterogeneous object design. A new CAD modeling approach is proposed to integrate the material information into geometric regions thus model the material distributions in the heterogeneous object. The gradient references are used to represent the complex geometry heterogeneous objects which have simultaneous geometry intricacies and accurate material distributions. The gradient references helps in flexible manipulability and control to heterogeneous objects, which guarantees the local control over gradient regions of developed heterogeneous objects. A systematic approach on data flow, processing, computer visualizat...
Computational modelling of evolution: ecosystems and language
Lipowski, Adam
2008-01-01
Recently, computational modelling became a very important research tool that enables us to study problems that for decades evaded scientific analysis. Evolutionary systems are certainly examples of such problems: they are composed of many units that might reproduce, diffuse, mutate, die, or in some cases for example communicate. These processes might be of some adaptive value, they influence each other and occur on various time scales. That is why such systems are so difficult to study. In this paper we briefly review some computational approaches, as well as our contributions, to the evolution of ecosystems and language. We start from Lotka-Volterra equations and the modelling of simple two-species prey-predator systems. Such systems are canonical example for studying oscillatory behaviour in competitive populations. Then we describe various approaches to study long-term evolution of multi-species ecosystems. We emphasize the need to use models that take into account both ecological and evolutionary processe...
Queuing theory models for computer networks
Galant, David C.
1989-01-01
A set of simple queuing theory models which can model the average response of a network of computers to a given traffic load has been implemented using a spreadsheet. The impact of variations in traffic patterns and intensities, channel capacities, and message protocols can be assessed using them because of the lack of fine detail in the network traffic rates, traffic patterns, and the hardware used to implement the networks. A sample use of the models applied to a realistic problem is included in appendix A. Appendix B provides a glossary of terms used in this paper. This Ames Research Center computer communication network is an evolving network of local area networks (LANs) connected via gateways and high-speed backbone communication channels. Intelligent planning of expansion and improvement requires understanding the behavior of the individual LANs as well as the collection of networks as a whole.
Loneliness and solitude in adolescence: A confirmatory factor analysis of alternative models
DEFF Research Database (Denmark)
Goossens, Luc; Lasgaard, Mathias; Luyckx, Koen;
2009-01-01
The present study tested a four-factor model of adolescent loneliness and solitude that comprises peer-related loneliness, family loneliness, negative attitude toward solitude, and positive attitude toward solitude. Nine different instruments for a total of 14 scales and derivative subscales were...... of the Loneliness and Aloneness Scale for Children and Adolescents (LACA) is recommended, because the instrument measures all four aspects of the model. Implications for current theories on adolescent loneliness and associated phenomena, such as adolescents' attitude toward being on their own, are briefly discussed....
Modelling the Progression of Male Swimmers’ Performances through Adolescence
Directory of Open Access Journals (Sweden)
Shilo J. Dormehl
2016-01-01
Full Text Available Insufficient data on adolescent athletes is contributing to the challenges facing youth athletic development and accurate talent identification. The purpose of this study was to model the progression of male sub-elite swimmers’ performances during adolescence. The performances of 446 males (12–19 year olds competing in seven individual events (50, 100, 200 m freestyle, 100 m backstroke, breaststroke, butterfly, 200 m individual medley over an eight-year period at an annual international schools swimming championship, run under FINA regulations were collected. Quadratic functions for each event were determined using mixed linear models. Thresholds of peak performance were achieved between the ages of 18.5 ± 0.1 (50 m freestyle and 200 m individual medley and 19.8 ± 0.1 (100 m butterfly years. The slowest rate of improvement was observed in the 200 m individual medley (20.7% and the highest in the 100 m butterfly (26.2%. Butterfly does however appear to be one of the last strokes in which males specialise. The models may be useful as talent identification tools, as they predict the age at which an average sub-elite swimmer could potentially peak. The expected rate of improvement could serve as a tool in which to monitor and evaluate benchmarks.
Middle Grades' School Models and Their Impact on Early Adolescent Self-Esteem
Booth, Margaret Zoller; Sheehan, Heather Chase; Earley, Mark A.
2007-01-01
Throughout the world, school grade structures are most variable during the early adolescent years when students can find themselves in a variety of school models. This paper investigates the impact of two popular school models in the United States (middle school and K-8) on the self-esteem and self-concept of early adolescents. Based on mixed…
Testing a Gender Additive Model: The Role of Body Image in Adolescent Depression
Bearman, Sarah Kate; Stice, Eric
2008-01-01
Despite consistent evidence that adolescent girls are at greater risk of developing depression than adolescent boys, risk factor models that account for this difference have been elusive. The objective of this research was to examine risk factors proposed by the "gender additive" model of depression that attempts to partially explain the increased…
Sticker DNA computer model--PartⅡ:Application
Institute of Scientific and Technical Information of China (English)
XU Jin; LI Sanping; DONG Yafei; WEI Xiaopeng
2004-01-01
Sticker model is one of the basic models in the DNA computer models. This model is coded with single-double stranded DNA molecules. It has the following advantages that the operations require no strands extension and use no enzymes; What's more, the materials are reusable. Therefore, it arouses attention and interest of scientists in many fields. In this paper, we extend and improve the sticker model, which will be definitely beneficial to the construction of DNA computer. This paper is the second part of our series paper, which mainly focuses on the application of sticker model. It mainly consists of the following three sections: the matrix representation of sticker model is first presented; then a brief review of the past research on graph and combinatorial optimization, such as the minimal set covering problem, the vertex covering problem, Hamiltonian path or cycle problem, the maximal clique problem, the maximal independent problem and the Steiner spanning tree problem, is described; Finally a DNA algorithm for the graph isomorphic problem based on the sticker model is given.
Computing the complexity for Schelling segregation models
Gerhold, Stefan; Glebsky, Lev; Schneider, Carsten; Weiss, Howard; Zimmermann, Burkhard
2008-12-01
The Schelling segregation models are "agent based" population models, where individual members of the population (agents) interact directly with other agents and move in space and time. In this note we study one-dimensional Schelling population models as finite dynamical systems. We define a natural notion of entropy which measures the complexity of the family of these dynamical systems. The entropy counts the asymptotic growth rate of the number of limit states. We find formulas and deduce precise asymptotics for the number of limit states, which enable us to explicitly compute the entropy.
Computer Modelling of 3D Geological Surface
Kodge, B G
2011-01-01
The geological surveying presently uses methods and tools for the computer modeling of 3D-structures of the geographical subsurface and geotechnical characterization as well as the application of geoinformation systems for management and analysis of spatial data, and their cartographic presentation. The objectives of this paper are to present a 3D geological surface model of Latur district in Maharashtra state of India. This study is undertaken through the several processes which are discussed in this paper to generate and visualize the automated 3D geological surface model of a projected area.
Prins Richard G; van Empelen Pepijn; Beenackers Marielle A; Brug Johannes; Oenema Anke
2010-01-01
Abstract Background Increasing physical activity (PA) among adolescents is an important health promotion goal. PA has numerous positive health effects, but the majority of Dutch adolescents do not meet PA requirements. The present paper describes the systematic development of a theory-based computer-tailored intervention, YouRAction, which targets individual and environmental factors determining PA among adolescents. Design The intervention development was guided by the Intervention Mapping p...
Attacker Modelling in Ubiquitous Computing Systems
DEFF Research Database (Denmark)
Papini, Davide
, localisation services and many others. These technologies can be classified under the name of ubiquitous systems. The term Ubiquitous System dates back to 1991 when Mark Weiser at Xerox PARC Lab first referred to it in writing. He envisioned a future where computing technologies would have been melted...... in with our everyday life. This future is visible to everyone nowadays: terms like smartphone, cloud, sensor, network etc. are widely known and used in our everyday life. But what about the security of such systems. Ubiquitous computing devices can be limited in terms of energy, computing power and memory...... attacker remain somehow undened and still under extensive investigation. This Thesis explores the nature of the ubiquitous attacker with a focus on how she interacts with the physical world and it denes a model that captures the abilities of the attacker. Furthermore a quantitative implementation...
Molecular Sieve Bench Testing and Computer Modeling
Mohamadinejad, Habib; DaLee, Robert C.; Blackmon, James B.
1995-01-01
The design of an efficient four-bed molecular sieve (4BMS) CO2 removal system for the International Space Station depends on many mission parameters, such as duration, crew size, cost of power, volume, fluid interface properties, etc. A need for space vehicle CO2 removal system models capable of accurately performing extrapolated hardware predictions is inevitable due to the change of the parameters which influences the CO2 removal system capacity. The purpose is to investigate the mathematical techniques required for a model capable of accurate extrapolated performance predictions and to obtain test data required to estimate mass transfer coefficients and verify the computer model. Models have been developed to demonstrate that the finite difference technique can be successfully applied to sorbents and conditions used in spacecraft CO2 removal systems. The nonisothermal, axially dispersed, plug flow model with linear driving force for 5X sorbent and pore diffusion for silica gel are then applied to test data. A more complex model, a non-darcian model (two dimensional), has also been developed for simulation of the test data. This model takes into account the channeling effect on column breakthrough. Four FORTRAN computer programs are presented: a two-dimensional model of flow adsorption/desorption in a packed bed; a one-dimensional model of flow adsorption/desorption in a packed bed; a model of thermal vacuum desorption; and a model of a tri-sectional packed bed with two different sorbent materials. The programs are capable of simulating up to four gas constituents for each process, which can be increased with a few minor changes.
Williams, John Kino Yamaguchi; Else, 'Iwalani R. N.; Goebert, Deborah A; Nishimura, Stephanie T.; Hishinuma, Earl S.; Andrade, Naleen N.
2013-01-01
Few studies have examined the effect of ethnicity and cultural identity on substance use among Asian and Pacific Islander adolescents. A cross-sequential study conducted in Hawai'i with 144 Japanese American and part-Japanese American adolescents assessed a model integrating Japanese ethnicity, cultural identity, substance use, major life events, and social support. Japanese American adolescents scored higher on the Japanese Culture Scale and on the Peers’ Social Support than the part-Japanes...
Mohamadian, Hashem; Ghannaee Arani, Mohammad
2014-01-01
Objectives Physical activity behavior begins to decline during adolescence and continues to decrease throughout young adulthood. This study aims to explain factors that influence physical activity behavior in a sample of female adolescents using a health promotion model framework. Methods This cross-sectional survey was used to explore physical activity behavior among a sample of female adolescents. Participants completed measures of physical activity, perceived self-efficacy, self-esteem, so...
McPherson, Mary Elizabeth
2004-01-01
This study examines the relationship of role parenting behaviors and adolescent depression in adolescent outcomes. Parenting behaviors considered were authoritative parenting, parental monitoring, and parental care. Adolescent outcomes considered were depression, alcohol use, tobacco use, and grades. A path model was employed to examine these variables together. A sample of (n=3,174) of 9th -12th grade high school students from seven contiguous counties in rural Virginia were examined on ...
Computer Modelling and Simulation for Inventory Control
Directory of Open Access Journals (Sweden)
G.K. Adegoke
2012-07-01
Full Text Available This study concerns the role of computer simulation as a device for conducting scientific experiments on inventory control. The stores function utilizes a bulk of physical assets and engages a bulk of financial resources in a manufacturing outfit therefore there is a need for an efficient inventory control. The reason being that inventory control reduces cost of production and thereby facilitates the effective and efficient accomplishment of production objectives of an organization. Some mathematical and statistical models were used to compute the Economic Order Quantity (EOQ. Test data were gotten from a manufacturing company and same were simulated. The results generated were used to predict a real life situation and have been presented and discussed. The language of implementation for the three models is Turbo Pascal due to its capability, generality and flexibility as a scientific programming language.
Computational hemodynamics theory, modelling and applications
Tu, Jiyuan; Wong, Kelvin Kian Loong
2015-01-01
This book discusses geometric and mathematical models that can be used to study fluid and structural mechanics in the cardiovascular system. Where traditional research methodologies in the human cardiovascular system are challenging due to its invasive nature, several recent advances in medical imaging and computational fluid and solid mechanics modelling now provide new and exciting research opportunities. This emerging field of study is multi-disciplinary, involving numerical methods, computational science, fluid and structural mechanics, and biomedical engineering. Certainly any new student or researcher in this field may feel overwhelmed by the wide range of disciplines that need to be understood. This unique book is one of the first to bring together knowledge from multiple disciplines, providing a starting point to each of the individual disciplines involved, attempting to ease the steep learning curve. This book presents elementary knowledge on the physiology of the cardiovascular system; basic knowl...
Computer modeling of a compact isochronous cyclotron
Smirnov, V. L.
2015-11-01
The computer modeling methods of a compact isochronous cyclotron are described. The main stages of analysis of accelerator facilities systems are considered. The described methods are based on theoretical fundamentals of cyclotron physics and mention highlights of creation of the physical project of a compact cyclotron. The main attention is paid to the analysis of the beam dynamics, formation of a magnetic field, stability of the movement, and a realistic assessment of intensity of the generated bunch of particles. In the article, the stages of development of the accelerator computer model, analytical ways of assessment of the accelerator parameters, and the basic technique of the numerical analysis of dynamics of the particles are described.
Computer modeling of flocculated multicomponent systems
Energy Technology Data Exchange (ETDEWEB)
Dabros, T. [Natural Resources Canada, CANMET Advanced Separation Technologies Laboratory, Devon, AB (Canada)
2004-07-01
The phenomenological models of settling and sediment consolidation were presented along with efficient and accurate numerical methods of solving conservation laws. This presentation provides project results and conclusions and future work in sand consolidation. It contains information on the hindered settling of multicomponent systems; hindered settling and consolidation including numerical results; and modeling multiphase flow using computational dynamics (CFD), a computer-based tool for simulating the behavior of systems involving fluid flow, heat transfer and other related physical processes. Efficient and accurate algorithms were recently developed to handle a wide class of conservation laws problems. It was concluded that solid effective stress can be accounted for in the continuity equation and excess pore pressure can be calculated from the solids concentration profile. tabs., figs.
Computational fluid dynamics modelling in cardiovascular medicine.
Morris, Paul D; Narracott, Andrew; von Tengg-Kobligk, Hendrik; Silva Soto, Daniel Alejandro; Hsiao, Sarah; Lungu, Angela; Evans, Paul; Bressloff, Neil W; Lawford, Patricia V; Hose, D Rodney; Gunn, Julian P
2016-01-01
This paper reviews the methods, benefits and challenges associated with the adoption and translation of computational fluid dynamics (CFD) modelling within cardiovascular medicine. CFD, a specialist area of mathematics and a branch of fluid mechanics, is used routinely in a diverse range of safety-critical engineering systems, which increasingly is being applied to the cardiovascular system. By facilitating rapid, economical, low-risk prototyping, CFD modelling has already revolutionised research and development of devices such as stents, valve prostheses, and ventricular assist devices. Combined with cardiovascular imaging, CFD simulation enables detailed characterisation of complex physiological pressure and flow fields and the computation of metrics which cannot be directly measured, for example, wall shear stress. CFD models are now being translated into clinical tools for physicians to use across the spectrum of coronary, valvular, congenital, myocardial and peripheral vascular diseases. CFD modelling is apposite for minimally-invasive patient assessment. Patient-specific (incorporating data unique to the individual) and multi-scale (combining models of different length- and time-scales) modelling enables individualised risk prediction and virtual treatment planning. This represents a significant departure from traditional dependence upon registry-based, population-averaged data. Model integration is progressively moving towards 'digital patient' or 'virtual physiological human' representations. When combined with population-scale numerical models, these models have the potential to reduce the cost, time and risk associated with clinical trials. The adoption of CFD modelling signals a new era in cardiovascular medicine. While potentially highly beneficial, a number of academic and commercial groups are addressing the associated methodological, regulatory, education- and service-related challenges.
Method of generating a computer readable model
DEFF Research Database (Denmark)
2008-01-01
A method of generating a computer readable model of a geometrical object constructed from a plurality of interconnectable construction elements, wherein each construction element has a number of connection elements for connecting the construction element with another construction element. The...... method comprises encoding a first and a second one of the construction elements as corresponding data structures, each representing the connection elements of the corresponding construction element, and each of the connection elements having associated with it a predetermined connection type. The method...
Computational Biology: Modeling Chronic Renal Allograft Injury.
Stegall, Mark D; Borrows, Richard
2015-01-01
New approaches are needed to develop more effective interventions to prevent long-term rejection of organ allografts. Computational biology provides a powerful tool to assess the large amount of complex data that is generated in longitudinal studies in this area. This manuscript outlines how our two groups are using mathematical modeling to analyze predictors of graft loss using both clinical and experimental data and how we plan to expand this approach to investigate specific mechanisms of chronic renal allograft injury.
Analytical performance modeling for computer systems
Tay, Y C
2013-01-01
This book is an introduction to analytical performance modeling for computer systems, i.e., writing equations to describe their performance behavior. It is accessible to readers who have taken college-level courses in calculus and probability, networking and operating systems. This is not a training manual for becoming an expert performance analyst. Rather, the objective is to help the reader construct simple models for analyzing and understanding the systems that they are interested in.Describing a complicated system abstractly with mathematical equations requires a careful choice of assumpti
ADGEN: ADjoint GENerator for computer models
Energy Technology Data Exchange (ETDEWEB)
Worley, B.A.; Pin, F.G.; Horwedel, J.E.; Oblow, E.M.
1989-05-01
This paper presents the development of a FORTRAN compiler and an associated supporting software library called ADGEN. ADGEN reads FORTRAN models as input and produces and enhanced version of the input model. The enhanced version reproduces the original model calculations but also has the capability to calculate derivatives of model results of interest with respect to any and all of the model data and input parameters. The method for calculating the derivatives and sensitivities is the adjoint method. Partial derivatives are calculated analytically using computer calculus and saved as elements of an adjoint matrix on direct assess storage. The total derivatives are calculated by solving an appropriate adjoint equation. ADGEN is applied to a major computer model of interest to the Low-Level Waste Community, the PRESTO-II model. PRESTO-II sample problem results reveal that ADGEN correctly calculates derivatives of response of interest with respect to 300 parameters. The execution time to create the adjoint matrix is a factor of 45 times the execution time of the reference sample problem. Once this matrix is determined, the derivatives with respect to 3000 parameters are calculated in a factor of 6.8 that of the reference model for each response of interest. For a single 3000 for determining these derivatives by parameter perturbations. The automation of the implementation of the adjoint technique for calculating derivatives and sensitivities eliminates the costly and manpower-intensive task of direct hand-implementation by reprogramming and thus makes the powerful adjoint technique more amenable for use in sensitivity analysis of existing models. 20 refs., 1 fig., 5 tabs.
Computational acoustic modeling of cetacean vocalizations
Gurevich, Michael Dixon
A framework for computational acoustic modeling of hypothetical vocal production mechanisms in cetaceans is presented. As a specific example, a model of a proposed source in the larynx of odontocetes is developed. Whales and dolphins generate a broad range of vocal sounds, but the exact mechanisms they use are not conclusively understood. In the fifty years since it has become widely accepted that whales can and do make sound, how they do so has remained particularly confounding. Cetaceans' highly divergent respiratory anatomy, along with the difficulty of internal observation during vocalization have contributed to this uncertainty. A variety of acoustical, morphological, ethological and physiological evidence has led to conflicting and often disputed theories of the locations and mechanisms of cetaceans' sound sources. Computational acoustic modeling has been used to create real-time parametric models of musical instruments and the human voice. These techniques can be applied to cetacean vocalizations to help better understand the nature and function of these sounds. Extensive studies of odontocete laryngeal morphology have revealed vocal folds that are consistently similar to a known but poorly understood acoustic source, the ribbon reed. A parametric computational model of the ribbon reed is developed, based on simplified geometrical, mechanical and fluid models drawn from the human voice literature. The physical parameters of the ribbon reed model are then adapted to those of the odontocete larynx. With reasonable estimates of real physical parameters, both the ribbon reed and odontocete larynx models produce sounds that are perceptually similar to their real-world counterparts, and both respond realistically under varying control conditions. Comparisons of acoustic features of the real-world and synthetic systems show a number of consistencies. While this does not on its own prove that either model is conclusively an accurate description of the source, it
Computer Modeling of Human Delta Opioid Receptor
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Tatyana Dzimbova
2013-04-01
Full Text Available The development of selective agonists of δ-opioid receptor as well as the model of interaction of ligands with this receptor is the subjects of increased interest. In the absence of crystal structures of opioid receptors, 3D homology models with different templates have been reported in the literature. The problem is that these models are not available for widespread use. The aims of our study are: (1 to choose within recently published crystallographic structures templates for homology modeling of the human δ-opioid receptor (DOR; (2 to evaluate the models with different computational tools; and (3 to precise the most reliable model basing on correlation between docking data and in vitro bioassay results. The enkephalin analogues, as ligands used in this study, were previously synthesized by our group and their biological activity was evaluated. Several models of DOR were generated using different templates. All these models were evaluated by PROCHECK and MolProbity and relationship between docking data and in vitro results was determined. The best correlations received for the tested models of DOR were found between efficacy (erel of the compounds, calculated from in vitro experiments and Fitness scoring function from docking studies. New model of DOR was generated and evaluated by different approaches. This model has good GA341 value (0.99 from MODELLER, good values from PROCHECK (92.6% of most favored regions and MolProbity (99.5% of favored regions. Scoring function correlates (Pearson r = -0.7368, p-value = 0.0097 with erel of a series of enkephalin analogues, calculated from in vitro experiments. So, this investigation allows suggesting a reliable model of DOR. Newly generated model of DOR receptor could be used further for in silico experiments and it will give possibility for faster and more correct design of selective and effective ligands for δ-opioid receptor.
Ferrofluids: Modeling, numerical analysis, and scientific computation
Tomas, Ignacio
This dissertation presents some developments in the Numerical Analysis of Partial Differential Equations (PDEs) describing the behavior of ferrofluids. The most widely accepted PDE model for ferrofluids is the Micropolar model proposed by R.E. Rosensweig. The Micropolar Navier-Stokes Equations (MNSE) is a subsystem of PDEs within the Rosensweig model. Being a simplified version of the much bigger system of PDEs proposed by Rosensweig, the MNSE are a natural starting point of this thesis. The MNSE couple linear velocity u, angular velocity w, and pressure p. We propose and analyze a first-order semi-implicit fully-discrete scheme for the MNSE, which decouples the computation of the linear and angular velocities, is unconditionally stable and delivers optimal convergence rates under assumptions analogous to those used for the Navier-Stokes equations. Moving onto the much more complex Rosensweig's model, we provide a definition (approximation) for the effective magnetizing field h, and explain the assumptions behind this definition. Unlike previous definitions available in the literature, this new definition is able to accommodate the effect of external magnetic fields. Using this definition we setup the system of PDEs coupling linear velocity u, pressure p, angular velocity w, magnetization m, and magnetic potential ϕ We show that this system is energy-stable and devise a numerical scheme that mimics the same stability property. We prove that solutions of the numerical scheme always exist and, under certain simplifying assumptions, that the discrete solutions converge. A notable outcome of the analysis of the numerical scheme for the Rosensweig's model is the choice of finite element spaces that allow the construction of an energy-stable scheme. Finally, with the lessons learned from Rosensweig's model, we develop a diffuse-interface model describing the behavior of two-phase ferrofluid flows and present an energy-stable numerical scheme for this model. For a
Computational Modeling of Large Wildfires: A Roadmap
Coen, Janice L.
2010-08-01
Wildland fire behavior, particularly that of large, uncontrolled wildfires, has not been well understood or predicted. Our methodology to simulate this phenomenon uses high-resolution dynamic models made of numerical weather prediction (NWP) models coupled to fire behavior models to simulate fire behavior. NWP models are capable of modeling very high resolution (< 100 m) atmospheric flows. The wildland fire component is based upon semi-empirical formulas for fireline rate of spread, post-frontal heat release, and a canopy fire. The fire behavior is coupled to the atmospheric model such that low level winds drive the spread of the surface fire, which in turn releases sensible heat, latent heat, and smoke fluxes into the lower atmosphere, feeding back to affect the winds directing the fire. These coupled dynamic models capture the rapid spread downwind, flank runs up canyons, bifurcations of the fire into two heads, and rough agreement in area, shape, and direction of spread at periods for which fire location data is available. Yet, intriguing computational science questions arise in applying such models in a predictive manner, including physical processes that span a vast range of scales, processes such as spotting that cannot be modeled deterministically, estimating the consequences of uncertainty, the efforts to steer simulations with field data ("data assimilation"), lingering issues with short term forecasting of weather that may show skill only on the order of a few hours, and the difficulty of gathering pertinent data for verification and initialization in a dangerous environment. © 2010 IEEE.
Interlanguages and synchronic models of computation
Berka, Alexander Victor
2010-01-01
A novel language system has given rise to promising alternatives to standard formal and processor network models of computation. An interstring linked with a abstract machine environment, shares sub-expressions, transfers data, and spatially allocates resources for the parallel evaluation of dataflow. Formal models called the a-Ram family are introduced, designed to support interstring programming languages (interlanguages). Distinct from dataflow, graph rewriting, and FPGA models, a-Ram instructions are bit level and execute in situ. They support sequential and parallel languages without the space/time overheads associated with the Turing Machine and l-calculus, enabling massive programs to be simulated. The devices of one a-Ram model, called the Synchronic A-Ram, are fully connected and simpler than FPGA LUT's. A compiler for an interlanguage called Space, has been developed for the Synchronic A-Ram. Space is MIMD. strictly typed, and deterministic. Barring memory allocation and compilation, modules are ref...
Computer models for optimizing radiation therapy
International Nuclear Information System (INIS)
The aim of this contribution is to outline how methods of system analysis, control therapy and modelling can be applied to simulate normal and malignant cell growth and to optimize cancer treatment as for instance radiation therapy. Based on biological observations and cell kinetic data, several types of models have been developed describing the growth of tumor spheroids and the cell renewal of normal tissue. The irradiation model is represented by the so-called linear-quadratic model describing the survival fraction as a function of the dose. Based thereon, numerous simulation runs for different treatment schemes can be performed. Thus, it is possible to study the radiation effect on tumor and normal tissue separately. Finally, this method enables a computer-assisted recommendation for an optimal patient-specific treatment schedule prior to clinical therapy. (orig.)
Computational Design Modelling : Proceedings of the Design Modelling Symposium
Kilian, Axel; Palz, Norbert; Scheurer, Fabian
2012-01-01
This book publishes the peer-reviewed proceeding of the third Design Modeling Symposium Berlin . The conference constitutes a platform for dialogue on experimental practice and research within the field of computationally informed architectural design. More than 60 leading experts the computational processes within the field of computationally informed architectural design to develop a broader and less exotic building practice that bears more subtle but powerful traces of the complex tool set and approaches we have developed and studied over recent years. The outcome are new strategies for a reasonable and innovative implementation of digital potential in truly innovative and radical design guided by both responsibility towards processes and the consequences they initiate.
A neural computational model of incentive salience.
Directory of Open Access Journals (Sweden)
Jun Zhang
2009-07-01
Full Text Available Incentive salience is a motivational property with 'magnet-like' qualities. When attributed to reward-predicting stimuli (cues, incentive salience triggers a pulse of 'wanting' and an individual is pulled toward the cues and reward. A key computational question is how incentive salience is generated during a cue re-encounter, which combines both learning and the state of limbic brain mechanisms. Learning processes, such as temporal-difference models, provide one way for stimuli to acquire cached predictive values of rewards. However, empirical data show that subsequent incentive values are also modulated on the fly by dynamic fluctuation in physiological states, altering cached values in ways requiring additional motivation mechanisms. Dynamic modulation of incentive salience for a Pavlovian conditioned stimulus (CS or cue occurs during certain states, without necessarily requiring (relearning about the cue. In some cases, dynamic modulation of cue value occurs during states that are quite novel, never having been experienced before, and even prior to experience of the associated unconditioned reward in the new state. Such cases can include novel drug-induced mesolimbic activation and addictive incentive-sensitization, as well as natural appetite states such as salt appetite. Dynamic enhancement specifically raises the incentive salience of an appropriate CS, without necessarily changing that of other CSs. Here we suggest a new computational model that modulates incentive salience by integrating changing physiological states with prior learning. We support the model with behavioral and neurobiological data from empirical tests that demonstrate dynamic elevations in cue-triggered motivation (involving natural salt appetite, and drug-induced intoxication and sensitization. Our data call for a dynamic model of incentive salience, such as presented here. Computational models can adequately capture fluctuations in cue-triggered 'wanting' only by
Tsai, Chia-Ching; Chang, Chih-Hsiang
2007-01-01
This study investigates the effect of advertising with physically attractive models on male and female adolescents. The findings suggest that highly attractive models are less effective than those who are normally attractive. Implications of social comparison are discussed.
Alcohol Consumption Among Scholarized Adolescents: A Socio-Communitarian Model
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María Elena Villarreal-González
2010-12-01
Full Text Available The aim of this study is to analyze the relationships that the individual, family, social and school variables have with the risk of alcohol consumption among adolescents. This is an explanatory causal study. The sample consisted of 1,245 adolescents of both sexes drawn from two secondary level and two pre-university level educational institutions, and were all aged between 12 and 17 years old. Stratified probability sampling was used, taking into account the proportion of students in each grade, level, group and timetable. To analyze the data, a structural equation model was calculated that explained 66% of the variance. The results showed that community social support and family functioning were indirectly related to alcohol consumption. The former was positively and significantly related, through friends’ support and also alcohol use by family and friends, while the latter was related through two paths: firstly, a positive and significant relationship, with family support and alcohol use by family and friends and, secondly, positively through school adjustment and school self-esteem which was negatively related with alcohol consumption. A significant and positive relationship was also observed between family functioning and social support. The results are discussed in terms of the most relevant studies on the subject of this research and the methodological limitations of this study are also considered.
Modeling problem behaviors in a nationally representative sample of adolescents.
O'Connor, Kate L; Dolphin, Louise; Fitzgerald, Amanda; Dooley, Barbara
2016-07-01
Research on multiple problem behaviors has focused on the concept of Problem Behavior Syndrome (PBS). Problem Behavior Theory (PBT) is a complex and comprehensive social-psychological framework designed to explain the development of a range of problem behaviors. This study examines the structure of PBS and the applicability of PBT in adolescents. Participants were 6062 adolescents; aged 12-19 (51.3% female) who took part in the My World Survey-Second Level (MWS-SL). Regarding PBS, Confirmatory Factor Analysis established that problem behaviors, such as alcohol and drug use loaded significantly onto a single, latent construct for males and females. Using Structural Equation Modeling, the PBT framework was found to be a good fit for males and females. Socio-demographic, perceived environment system and personality accounted for over 40% of the variance in problem behaviors for males and females. Our findings have important implications for understanding how differences in engaging in problem behaviors vary by gender. PMID:27161989
Directory of Open Access Journals (Sweden)
Jorge Delva
2012-02-01
Full Text Available We used longitudinal data to investigate the relationship between computer use in internet cafés and smoking/drinking behavior among Chinese adolescents and young adults. Data are from two waves of the China Health and Nutrition Survey (2004 and 2006. Fixed effects models were used to examine if changes in internet café use were associated with changes in cigarette smoking and drinking of alcohol. Male café users spent on average 17.3 hours in front of the computer/week. This was associated with an increase in the probability of being a current smoker by 13.3% and with smoking 1.7 more cigarettes. Female café users spent on average 11 hours on the computer/week. This was associated with an increase in the probability of drinking wine and/or liquor by 14.74% and was not associated with smoking. Internet cafés are an important venue by which adolescent and young adults in China are exposed to smoking and drinking. Multi-component interventions are needed ranging from policies regulating cigarette and alcohol availability in these venues to anti-tobacco campaigns aimed at the general population but also at individuals who frequent these establishments.
DYNAMIC TASK PARTITIONING MODEL IN PARALLEL COMPUTING
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Javed Ali
2012-04-01
Full Text Available Parallel computing systems compose task partitioning strategies in a true multiprocessing manner. Such systems share the algorithm and processing unit as computing resources which leads to highly inter process communications capabilities. The main part of the proposed algorithm is resource management unit which performs task partitioning and co-scheduling .In this paper, we present a technique for integrated task partitioning and co-scheduling on the privately owned network. We focus on real-time and non preemptive systems. A large variety of experiments have been conducted on the proposed algorithm using synthetic and real tasks. Goal of computation model is to provide a realistic representation of the costs of programming The results show the benefit of the task partitioning. The main characteristics of our method are optimal scheduling and strong link between partitioning, scheduling and communication. Some important models for task partitioning are also discussed in the paper. We target the algorithm for task partitioning which improve the inter process communication between the tasks and use the recourses of the system in the efficient manner. The proposed algorithm contributes the inter-process communication cost minimization amongst the executing processes.
D.S. Sieh; A.L.C. Dikkers; J.M.A. Visser-Meily; A.M. Meijer
2012-01-01
This article was inspired by Rolland’s Family Systems-Illness (FSI) model, aiming to predict adolescent stress as a function of parental illness type. Ninety-nine parents with a chronic medical condition, 82 partners, and 158 adolescent children (51 % girls; mean age = 15.1 years) participated in th
Wright, Marcie S.; Wilson, Dawn K.; Griffin, Sarah; Evans, Alexandra
2010-01-01
This study obtained qualitative data to assess how parental role modeling and parental social support influence physical activity in underserved (minority, low-income) adolescents. Fifty-two adolescents (22 males, 30 females; ages 10-14 years, 85% African-American) participated in a focus group (6-10 per group, same gender). Focus groups were…
Martel, Michelle M.; Pierce, Laura; Nigg, Joel T.; Jester, Jennifer M.; Adams, Kenneth; Puttler, Leon I.; Buu, Anne; Fitzgerald, Hiram; Zucker, Robert A.
2009-01-01
Temperament traits may increase risk for developmental psychopathology like Attention-Deficit/Hyperactivity Disorder (ADHD) and disruptive behaviors during childhood, as well as predisposing to substance abuse during adolescence. In the current study, a cascade model of trait pathways to adolescent substance abuse was examined. Component…
Self-Esteem and Delinquency in South Korean Adolescents: Latent Growth Modeling
Lee, Kyungeun; Lee, Julie
2012-01-01
This study examined the inter-related development of self-esteem and delinquency across three years. Participants were 3449 Korean high school adolescents (age M = 15.8, SD = 0.42, 1725 boys, 1724 girls) from Korea Youth Panel Study (KYPS), in 2005-2007, nationally representative of Korean adolescents. Latent growth modeling was employed for…
Guerry, J.D.; Prinstein, M.J.
2010-01-01
Virtually no longitudinal research has examined psychological characteristics or events that may lead to adolescent nonsuicidal self-injury (NSSI). This study tested a cognitive vulnerability-stress model as a predictor of NSSI trajectories. Clinically-referred adolescents (n = 143; 72% girls) compl
An Adolescent Nutrition Learning Model to Facilitate Behavior Change in Overweight Teens
Young, Kimberly J.; Ramsay, Samantha A.; Holyoke, Laura B.
2016-01-01
Understanding the process by which adolescents learn about nutrition is necessary for developing tailored education that leads to sustainable behavior change. Teens aged 15-17 participating in an obesity prevention program were interviewed. From the data, three themes emerged and informed development of an adolescent nutrition learning model. The…
Wadsworth, Martha E.; Raviv, Tali; Compas, Bruce E.; Connor-Smith, Jennifer K.
2005-01-01
We tested several models of the associations among economic strain, life stress, coping, involuntary stress responses, and psychological symptoms in a sample of 57 parent-adolescent dyads from rural, lower-income families. Economic strain and life stress predicted symptoms for both parents and adolescents. Stressor-symptom specificity was found…
Rith-Najarian, Leslie R.; McLaughlin, Katie A.; Sheridan, Margaret A.; Nock, Matthew K.
2014-01-01
Extensive research among adults supports the biopsychosocial (BPS) model of challenge and threat, which describes relationships among stress appraisals, physiological stress reactivity, and performance; however, no previous studies have examined these relationships in adolescents. Perceptions of stressors as well as physiological reactivity to stress increase during adolescence, highlighting the importance of understanding the relationships among stress appraisals, physiological reactivity, a...
Computer modeling for optimal placement of gloveboxes
International Nuclear Information System (INIS)
Reduction of the nuclear weapons stockpile and the general downsizing of the nuclear weapons complex has presented challenges for Los Alamos. One is to design an optimized fabrication facility to manufacture nuclear weapon primary components (pits) in an environment of intense regulation and shrinking budgets. Historically, the location of gloveboxes in a processing area has been determined without benefit of industrial engineering studies to ascertain the optimal arrangement. The opportunity exists for substantial cost savings and increased process efficiency through careful study and optimization of the proposed layout by constructing a computer model of the fabrication process. This paper presents an integrative two- stage approach to modeling the casting operation for pit fabrication. The first stage uses a mathematical technique for the formulation of the facility layout problem; the solution procedure uses an evolutionary heuristic technique. The best solutions to the layout problem are used as input to the second stage - a computer simulation model that assesses the impact of competing layouts on operational performance. The focus of the simulation model is to determine the layout that minimizes personnel radiation exposures and nuclear material movement, and maximizes the utilization of capacity for finished units
Computer Generated Cardiac Model For Nuclear Medicine
Hills, John F.; Miller, Tom R.
1981-07-01
A computer generated mathematical model of a thallium-201 myocardial image is described which is based on realistic geometric and physiological assumptions. The left ventricle is represented by an ellipsoid truncated by aortic and mitral valve planes. Initially, an image of a motionless left ventricle is calculated with the location, size, and relative activity of perfusion defects selected by the designer. The calculation includes corrections for photon attenuation by overlying structures and the relative distribution of activity within the tissues. Motion of the ventricular walls is simulated either by a weighted sum of images at different stages in the cardiac cycle or by a blurring function whose width varies with position. Camera and collimator blurring are estimated by the MTF of the system measured at a representative depth in a phantom. Statistical noise is added using a Poisson random number generator. The usefulness of this model is due to two factors: the a priori characterization of location and extent of perfusion defects and the strong visual similarity of the images to actual clinical studies. These properties should permit systematic evaluation of image processing algorithms using this model. The principles employed in developing this cardiac image model can readily be applied to the simulation of other nuclear medicine studies and to other medical imaging modalities including computed tomography, ultrasound, and digital radiography.
McKinney, Cliff; Renk, Kimberly
2008-01-01
Although parent-adolescent interactions have been examined, relevant variables have not been integrated into a multivariate model. As a result, this study examined a multivariate model of parent-late adolescent gender dyads in an attempt to capture important predictors in late adolescents' important and unique transition to adulthood. The sample…
COMMON PHASES OF COMPUTER FORENSICS INVESTIGATION MODELS
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Yunus Yusoff
2011-06-01
Full Text Available The increasing criminal activities using digital information as the means or targets warrant for a structured manner in dealing with them. Since 1984 when a formalized process been introduced, a great number of new and improved computer forensic investigation processes have been developed. In this paper, we reviewed a few selected investigation processes that have been produced throughout the yearsand then identified the commonly shared processes. Hopefully, with the identification of the commonly shard process, it would make it easier for the new users to understand the processes and also to serve as the basic underlying concept for the development of a new set of processes. Based on the commonly shared processes, we proposed a generic computer forensics investigation model, known as GCFIM.
Computational Models for Analysis of Illicit Activities
DEFF Research Database (Denmark)
Nizamani, Sarwat
Numerous illicit activities happen in our society, which, from time to time affect the population by harming individuals directly or indirectly. Researchers from different disciplines have contributed to developing strategies to analyze such activities, in order to help law enforcement agents dev...... population globally sensitive to specific world issues. The models discuss the dynamics of population in response to such issues. All the models presented in the thesis can be combined for a systematic analysis of illicit activities.......Numerous illicit activities happen in our society, which, from time to time affect the population by harming individuals directly or indirectly. Researchers from different disciplines have contributed to developing strategies to analyze such activities, in order to help law enforcement agents...... devise policies to minimize them. These activities include cybercrimes, terrorist attacks or violent actions in response to certain world issues. Beside such activities, there are several other related activities worth analyzing, for which computational models have been presented in this thesis...
Computational fluid dynamic modelling of cavitation
Deshpande, Manish; Feng, Jinzhang; Merkle, Charles L.
1993-01-01
Models in sheet cavitation in cryogenic fluids are developed for use in Euler and Navier-Stokes codes. The models are based upon earlier potential-flow models but enable the cavity inception point, length, and shape to be determined as part of the computation. In the present paper, numerical solutions are compared with experimental measurements for both pressure distribution and cavity length. Comparisons between models are also presented. The CFD model provides a relatively simple modification to an existing code to enable cavitation performance predictions to be included. The analysis also has the added ability of incorporating thermodynamic effects of cryogenic fluids into the analysis. Extensions of the current two-dimensional steady state analysis to three-dimensions and/or time-dependent flows are, in principle, straightforward although geometrical issues become more complicated. Linearized models, however offer promise of providing effective cavitation modeling in three-dimensions. This analysis presents good potential for improved understanding of many phenomena associated with cavity flows.
A Graph Model for Imperative Computation
McCusker, Guy
2009-01-01
Scott's graph model is a lambda-algebra based on the observation that continuous endofunctions on the lattice of sets of natural numbers can be represented via their graphs. A graph is a relation mapping finite sets of input values to output values. We consider a similar model based on relations whose input values are finite sequences rather than sets. This alteration means that we are taking into account the order in which observations are made. This new notion of graph gives rise to a model of affine lambda-calculus that admits an interpretation of imperative constructs including variable assignment, dereferencing and allocation. Extending this untyped model, we construct a category that provides a model of typed higher-order imperative computation with an affine type system. An appropriate language of this kind is Reynolds's Syntactic Control of Interference. Our model turns out to be fully abstract for this language. At a concrete level, it is the same as Reddy's object spaces model, which was the first "...
Computer models of vocal tract evolution: an overview and critique
B. de Boer; W. T. Fitch
2010-01-01
Human speech has been investigated with computer models since the invention of digital computers, and models of the evolution of speech first appeared in the late 1960s and early 1970s. Speech science and computer models have a long shared history because speech is a physical signal and can be model
Computational modeling of Li-ion batteries
Grazioli, D.; Magri, M.; Salvadori, A.
2016-08-01
This review focuses on energy storage materials modeling, with particular emphasis on Li-ion batteries. Theoretical and computational analyses not only provide a better understanding of the intimate behavior of actual batteries under operational and extreme conditions, but they may tailor new materials and shape new architectures in a complementary way to experimental approaches. Modeling can therefore play a very valuable role in the design and lifetime prediction of energy storage materials and devices. Batteries are inherently multi-scale, in space and time. The macro-structural characteristic lengths (the thickness of a single cell, for instance) are order of magnitudes larger than the particles that form the microstructure of the porous electrodes, which in turn are scale-separated from interface layers at which atomistic intercalations occur. Multi-physics modeling concepts, methodologies, and simulations at different scales, as well as scale transition strategies proposed in the recent literature are here revised. Finally, computational challenges toward the next generation of Li-ion batteries are discussed.
Modeling Reality - How Computers Mirror Life
Bialynicki-Birula, Iwo; Bialynicka-Birula, Iwona
2005-01-01
The bookModeling Reality covers a wide range of fascinating subjects, accessible to anyone who wants to learn about the use of computer modeling to solve a diverse range of problems, but who does not possess a specialized training in mathematics or computer science. The material presented is pitched at the level of high-school graduates, even though it covers some advanced topics (cellular automata, Shannon's measure of information, deterministic chaos, fractals, game theory, neural networks, genetic algorithms, and Turing machines). These advanced topics are explained in terms of well known simple concepts: Cellular automata - Game of Life, Shannon's formula - Game of twenty questions, Game theory - Television quiz, etc. The book is unique in explaining in a straightforward, yet complete, fashion many important ideas, related to various models of reality and their applications. Twenty-five programs, written especially for this book, are provided on an accompanying CD. They greatly enhance its pedagogical value and make learning of even the more complex topics an enjoyable pleasure.
Optimization and mathematical modeling in computer architecture
Sankaralingam, Karu; Nowatzki, Tony
2013-01-01
In this book we give an overview of modeling techniques used to describe computer systems to mathematical optimization tools. We give a brief introduction to various classes of mathematical optimization frameworks with special focus on mixed integer linear programming which provides a good balance between solver time and expressiveness. We present four detailed case studies -- instruction set customization, data center resource management, spatial architecture scheduling, and resource allocation in tiled architectures -- showing how MILP can be used and quantifying by how much it outperforms t
Dynamical Models for Computer Viruses Propagation
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José R. C. Piqueira
2008-01-01
Full Text Available Nowadays, digital computer systems and networks are the main engineering tools, being used in planning, design, operation, and control of all sizes of building, transportation, machinery, business, and life maintaining devices. Consequently, computer viruses became one of the most important sources of uncertainty, contributing to decrease the reliability of vital activities. A lot of antivirus programs have been developed, but they are limited to detecting and removing infections, based on previous knowledge of the virus code. In spite of having good adaptation capability, these programs work just as vaccines against diseases and are not able to prevent new infections based on the network state. Here, a trial on modeling computer viruses propagation dynamics relates it to other notable events occurring in the network permitting to establish preventive policies in the network management. Data from three different viruses are collected in the Internet and two different identification techniques, autoregressive and Fourier analyses, are applied showing that it is possible to forecast the dynamics of a new virus propagation by using the data collected from other viruses that formerly infected the network.
Computational social dynamic modeling of group recruitment.
Energy Technology Data Exchange (ETDEWEB)
Berry, Nina M.; Lee, Marinna; Pickett, Marc; Turnley, Jessica Glicken (Sandia National Laboratories, Albuquerque, NM); Smrcka, Julianne D. (Sandia National Laboratories, Albuquerque, NM); Ko, Teresa H.; Moy, Timothy David (Sandia National Laboratories, Albuquerque, NM); Wu, Benjamin C.
2004-01-01
The Seldon software toolkit combines concepts from agent-based modeling and social science to create a computationally social dynamic model for group recruitment. The underlying recruitment model is based on a unique three-level hybrid agent-based architecture that contains simple agents (level one), abstract agents (level two), and cognitive agents (level three). This uniqueness of this architecture begins with abstract agents that permit the model to include social concepts (gang) or institutional concepts (school) into a typical software simulation environment. The future addition of cognitive agents to the recruitment model will provide a unique entity that does not exist in any agent-based modeling toolkits to date. We use social networks to provide an integrated mesh within and between the different levels. This Java based toolkit is used to analyze different social concepts based on initialization input from the user. The input alters a set of parameters used to influence the values associated with the simple agents, abstract agents, and the interactions (simple agent-simple agent or simple agent-abstract agent) between these entities. The results of phase-1 Seldon toolkit provide insight into how certain social concepts apply to different scenario development for inner city gang recruitment.
Analysis of a Model for Computer Virus Transmission
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Peng Qin
2015-01-01
Full Text Available Computer viruses remain a significant threat to computer networks. In this paper, the incorporation of new computers to the network and the removing of old computers from the network are considered. Meanwhile, the computers are equipped with antivirus software on the computer network. The computer virus model is established. Through the analysis of the model, disease-free and endemic equilibrium points are calculated. The stability conditions of the equilibria are derived. To illustrate our theoretical analysis, some numerical simulations are also included. The results provide a theoretical basis to control the spread of computer virus.
A computational model of motor neuron degeneration.
Le Masson, Gwendal; Przedborski, Serge; Abbott, L F
2014-08-20
To explore the link between bioenergetics and motor neuron degeneration, we used a computational model in which detailed morphology and ion conductance are paired with intracellular ATP production and consumption. We found that reduced ATP availability increases the metabolic cost of a single action potential and disrupts K+/Na+ homeostasis, resulting in a chronic depolarization. The magnitude of the ATP shortage at which this ionic instability occurs depends on the morphology and intrinsic conductance characteristic of the neuron. If ATP shortage is confined to the distal part of the axon, the ensuing local ionic instability eventually spreads to the whole neuron and involves fasciculation-like spiking events. A shortage of ATP also causes a rise in intracellular calcium. Our modeling work supports the notion that mitochondrial dysfunction can account for salient features of the paralytic disorder amyotrophic lateral sclerosis, including motor neuron hyperexcitability, fasciculation, and differential vulnerability of motor neuron subpopulations.
Computational models of intergroup competition and warfare.
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Letendre, Kenneth (University of New Mexico); Abbott, Robert G.
2011-11-01
This document reports on the research of Kenneth Letendre, the recipient of a Sandia Graduate Research Fellowship at the University of New Mexico. Warfare is an extreme form of intergroup competition in which individuals make extreme sacrifices for the benefit of their nation or other group to which they belong. Among animals, limited, non-lethal competition is the norm. It is not fully understood what factors lead to warfare. We studied the global variation in the frequency of civil conflict among countries of the world, and its positive association with variation in the intensity of infectious disease. We demonstrated that the burden of human infectious disease importantly predicts the frequency of civil conflict and tested a causal model for this association based on the parasite-stress theory of sociality. We also investigated the organization of social foraging by colonies of harvester ants in the genus Pogonomyrmex, using both field studies and computer models.
Modeling Reality: How Computers Mirror Life
International Nuclear Information System (INIS)
Modeling Reality: How Computers Mirror Life covers a wide range of modern subjects in complex systems, suitable not only for undergraduate students who want to learn about modelling 'reality' by using computer simulations, but also for researchers who want to learn something about subjects outside of their majors and need a simple guide. Readers are not required to have specialized training before they start the book. Each chapter is organized so as to train the reader to grasp the essential idea of simulating phenomena and guide him/her towards more advanced areas. The topics presented in this textbook fall into two categories. The first is at graduate level, namely probability, statistics, information theory, graph theory, and the Turing machine, which are standard topics in the course of information science and information engineering departments. The second addresses more advanced topics, namely cellular automata, deterministic chaos, fractals, game theory, neural networks, and genetic algorithms. Several topics included here (neural networks, game theory, information processing, etc) are now some of the main subjects of statistical mechanics, and many papers related to these interdisciplinary fields are published in Journal of Physics A: Mathematical and General, so readers of this journal will be familiar with the subject areas of this book. However, each area is restricted to an elementary level and if readers wish to know more about the topics they are interested in, they will need more advanced books. For example, on neural networks, the text deals with the back-propagation algorithm for perceptron learning. Nowadays, however, this is a rather old topic, so the reader might well choose, for example, Introduction to the Theory of Neural Computation by J Hertz et al (Perseus books, 1991) or Statistical Physics of Spin Glasses and Information Processing by H Nishimori (Oxford University Press, 2001) for further reading. Nevertheless, this book is worthwhile
HSV-2 and Substance Abuse amongst Adolescents: Insights through Mathematical Modelling
Directory of Open Access Journals (Sweden)
A. Mhlanga
2014-01-01
Full Text Available Herpes simplex virus infection is mostly spread and occurs more commonly among substance abusing adolescents as compared to the nonsubstance abusing. In this paper, a mathematical model for the spread of HSV-2 within a community with substance abusing adolescents is developed and analysed. The impacts of condom use and educational campaigns are examined. The study suggests that condom use is highly effective among adolescents, when we have more of them quitting than becoming substance abusers. Measures such as educational campaigns can be put in place to try and reduce adolescents from becoming substance abusers. Further, we applied optimal control theory to the proposed model. The controls represent condom use and educational campaigns. The objective is based on maximising the susceptible nonsubstance abusing adolescents, while minimising the susceptible substance abusing adolescents, the infectious nonsubstance abusing adolescents, and the infectious substance abusing adolescents. We used Pontrygin’s maximum principle to characterise the optimal levels of the two controls. The resulting optimality system is solved numerically. Overall, the application of the optimal control theory suggests that more effort should be devoted to condom use as compared to educational campaigns.
Direct modeling for computational fluid dynamics
Xu, Kun
2015-06-01
All fluid dynamic equations are valid under their modeling scales, such as the particle mean free path and mean collision time scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes (NS) equations. The current computational fluid dynamics (CFD) focuses on the numerical solution of partial differential equations (PDEs), and its aim is to get the accurate solution of these governing equations. Under such a CFD practice, it is hard to develop a unified scheme that covers flow physics from kinetic to hydrodynamic scales continuously because there is no such governing equation which could make a smooth transition from the Boltzmann to the NS modeling. The study of fluid dynamics needs to go beyond the traditional numerical partial differential equations. The emerging engineering applications, such as air-vehicle design for near-space flight and flow and heat transfer in micro-devices, do require further expansion of the concept of gas dynamics to a larger domain of physical reality, rather than the traditional distinguishable governing equations. At the current stage, the non-equilibrium flow physics has not yet been well explored or clearly understood due to the lack of appropriate tools. Unfortunately, under the current numerical PDE approach, it is hard to develop such a meaningful tool due to the absence of valid PDEs. In order to construct multiscale and multiphysics simulation methods similar to the modeling process of constructing the Boltzmann or the NS governing equations, the development of a numerical algorithm should be based on the first principle of physical modeling. In this paper, instead of following the traditional numerical PDE path, we introduce direct modeling as a principle for CFD algorithm development. Since all computations are conducted in a discretized space with limited cell resolution, the flow physics to be modeled has to be done in the mesh size and time step scales. Here, the CFD is more or less a direct
Stochastic linear programming models, theory, and computation
Kall, Peter
2011-01-01
This new edition of Stochastic Linear Programming: Models, Theory and Computation has been brought completely up to date, either dealing with or at least referring to new material on models and methods, including DEA with stochastic outputs modeled via constraints on special risk functions (generalizing chance constraints, ICC’s and CVaR constraints), material on Sharpe-ratio, and Asset Liability Management models involving CVaR in a multi-stage setup. To facilitate use as a text, exercises are included throughout the book, and web access is provided to a student version of the authors’ SLP-IOR software. Additionally, the authors have updated the Guide to Available Software, and they have included newer algorithms and modeling systems for SLP. The book is thus suitable as a text for advanced courses in stochastic optimization, and as a reference to the field. From Reviews of the First Edition: "The book presents a comprehensive study of stochastic linear optimization problems and their applications. … T...
Multiscale computational modelling of the heart
Smith, N. P.; Nickerson, D. P.; Crampin, E. J.; Hunter, P. J.
A computational framework is presented for integrating the electrical, mechanical and biochemical functions of the heart. Finite element techniques are used to solve the large-deformation soft tissue mechanics using orthotropic constitutive laws based in the measured fibre-sheet structure of myocardial (heart muscle) tissue. The reaction-diffusion equations governing electrical current flow in the heart are solved on a grid of deforming material points which access systems of ODEs representing the cellular processes underlying the cardiac action potential. Navier-Stokes equations are solved for coronary blood flow in a system of branching blood vessels embedded in the deforming myocardium and the delivery of oxygen and metabolites is coupled to the energy-dependent cellular processes. The framework presented here for modelling coupled physical conservation laws at the tissue and organ levels is also appropriate for other organ systems in the body and we briefly discuss applications to the lungs and the musculo-skeletal system. The computational framework is also designed to reach down to subcellular processes, including signal transduction cascades and metabolic pathways as well as ion channel electrophysiology, and we discuss the development of ontologies and markup language standards that will help link the tissue and organ level models to the vast array of gene and protein data that are now available in web-accessible databases.
Computational Models to Synthesize Human Walking
Institute of Scientific and Technical Information of China (English)
Lei Ren; David Howard; Laurence Kenney
2006-01-01
The synthesis of human walking is of great interest in biomechanics and biomimetic engineering due to its predictive capabilities and potential applications in clinical biomechanics, rehabilitation engineering and biomimetic robotics. In this paper,the various methods that have been used to synthesize humanwalking are reviewed from an engineering viewpoint. This involves a wide spectrum of approaches, from simple passive walking theories to large-scale computational models integrating the nervous, muscular and skeletal systems. These methods are roughly categorized under four headings: models inspired by the concept of a CPG (Central Pattern Generator), methods based on the principles of control engineering, predictive gait simulation using optimisation, and models inspired by passive walking theory. The shortcomings and advantages of these methods are examined, and future directions are discussed in the context of providing insights into the neural control objectives driving gait and improving the stability of the predicted gaits. Future advancements are likely to be motivated by improved understanding of neural control strategies and the subtle complexities of the musculoskeletal system during human locomotion. It is only a matter of time before predictive gait models become a practical and valuable tool in clinical diagnosis, rehabilitation engineering and robotics.
Computational modeling of intraocular gas dynamics
Noohi, P.; Abdekhodaie, M. J.; Cheng, Y. L.
2015-12-01
The purpose of this study was to develop a computational model to simulate the dynamics of intraocular gas behavior in pneumatic retinopexy (PR) procedure. The presented model predicted intraocular gas volume at any time and determined the tolerance angle within which a patient can maneuver and still gas completely covers the tear(s). Computational fluid dynamics calculations were conducted to describe PR procedure. The geometrical model was constructed based on the rabbit and human eye dimensions. SF6 in the form of pure and diluted with air was considered as the injected gas. The presented results indicated that the composition of the injected gas affected the gas absorption rate and gas volume. After injection of pure SF6, the bubble expanded to 2.3 times of its initial volume during the first 23 h, but when diluted SF6 was used, no significant expansion was observed. Also, head positioning for the treatment of retinal tear influenced the rate of gas absorption. Moreover, the determined tolerance angle depended on the bubble and tear size. More bubble expansion and smaller retinal tear caused greater tolerance angle. For example, after 23 h, for the tear size of 2 mm the tolerance angle of using pure SF6 is 1.4 times more than that of using diluted SF6 with 80% air. Composition of the injected gas and conditions of the tear in PR may dramatically affect the gas absorption rate and gas volume. Quantifying these effects helps to predict the tolerance angle and improve treatment efficiency.
Force field analysis: a model for promoting adolescents' involvement in their own health care.
MacDuffie, Heather; DePoy, Elizabeth
2004-07-01
This article advances a three-step model for engaging adolescents in shaping their own health care supports and services through systems and social change that rely on principles of force field analysis. Consistent with health promotion values and trends for evidence-based practice, force field analysis provides a systematic and multilevel approach to problem assessment, resolution, and social change that is particularly appropriate for adolescents. The article reviews relevant literature, proposes the model, and concludes with a comparative illustration and critical analysis of the use of force field analysis to promote adolescent health. PMID:15228786
Cumsille, Patricio; Darling, Nancy; Flaherty, Brian; Martinez, Maria Loreto
2009-01-01
Changes in the patterning of adolescents' beliefs about the legitimate domains of parental authority were modeled in 2,611 Chilean adolescents, 11-16 years old. Transitions in adolescents' belief patterns were studied over 3 years. Latent transition analysis (LTA) revealed 3 distinct patterns of beliefs--"parent control," "shared control," and…
Daniels, Elizabeth A.; Sherman, Aurora M.
2016-01-01
Using an experimental methodology, the present study investigated adolescents' attitudes toward media images of women in non-appearance-focused (CEO and military pilot) and appearance-focused occupations (model and actor). One hundred adolescent girls and 76 adolescent boys provided ratings of likability, competence, and similarity to self after…
Adolescents and Cyber Bullying: The Precaution Adoption Process Model
Chapin, John
2016-01-01
A survey of adolescents (N = 1,488) documented Facebook use and experience with cyber bullying. The study found that 84% of adolescents (middle school through college undergraduates) use Facebook, and that most users log on daily. While 30% of the sample reported being cyber bullied, only 12.5% quit using the site, and only 18% told a parent or…
den Hamer, Anouk; Konijn, Elly A; Keijer, Micha G
2014-02-01
The present study examined the role of media use in adolescents' cyberbullying behavior. Following previous research, we propose a Cyclic Process Model of face-to-face victimization and cyberbullying through two mediating processes of anger/frustration and antisocial media content. This model was tested utilizing a cross-sectional design with adolescent participants (N=892). Exposure to antisocial media content was measured with a newly developed content-based scale (i.e., the C-ME), showing good psychometric qualities. Results of structural equation modeling showed that adolescents' exposure to antisocial media content was significantly associated with cyberbullying behavior, especially in adolescents who experienced anger and frustration due to face-to-face victimization. Goodness of fit indices demonstrated a good fit of the theoretical model to the data and indicated that exposure to antisocial media content acts as an amplifier in a cyclic process of victimization-related anger and cyberbullying behavior. PMID:24015985
Preliminary Phase Field Computational Model Development
Energy Technology Data Exchange (ETDEWEB)
Li, Yulan [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Hu, Shenyang Y. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Xu, Ke [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Suter, Jonathan D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McCloy, John S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnson, Bradley R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
2014-12-15
This interim report presents progress towards the development of meso-scale models of magnetic behavior that incorporate microstructural information. Modeling magnetic signatures in irradiated materials with complex microstructures (such as structural steels) is a significant challenge. The complexity is addressed incrementally, using the monocrystalline Fe (i.e., ferrite) film as model systems to develop and validate initial models, followed by polycrystalline Fe films, and by more complicated and representative alloys. In addition, the modeling incrementally addresses inclusion of other major phases (e.g., martensite, austenite), minor magnetic phases (e.g., carbides, FeCr precipitates), and minor nonmagnetic phases (e.g., Cu precipitates, voids). The focus of the magnetic modeling is on phase-field models. The models are based on the numerical solution to the Landau-Lifshitz-Gilbert equation. From the computational standpoint, phase-field modeling allows the simulation of large enough systems that relevant defect structures and their effects on functional properties like magnetism can be simulated. To date, two phase-field models have been generated in support of this work. First, a bulk iron model with periodic boundary conditions was generated as a proof-of-concept to investigate major loop effects of single versus polycrystalline bulk iron and effects of single non-magnetic defects. More recently, to support the experimental program herein using iron thin films, a new model was generated that uses finite boundary conditions representing surfaces and edges. This model has provided key insights into the domain structures observed in magnetic force microscopy (MFM) measurements. Simulation results for single crystal thin-film iron indicate the feasibility of the model for determining magnetic domain wall thickness and mobility in an externally applied field. Because the phase-field model dimensions are limited relative to the size of most specimens used in
Methodical Approaches to Teaching of Computer Modeling in Computer Science Course
Rakhimzhanova, B. Lyazzat; Issabayeva, N. Darazha; Khakimova, Tiyshtik; Bolyskhanova, J. Madina
2015-01-01
The purpose of this study was to justify of the formation technique of representation of modeling methodology at computer science lessons. The necessity of studying computer modeling is that the current trends of strengthening of general education and worldview functions of computer science define the necessity of additional research of the…
Parallel Computing for Terrestrial Ecosystem Carbon Modeling
International Nuclear Information System (INIS)
Terrestrial ecosystems are a primary component of research on global environmental change. Observational and modeling research on terrestrial ecosystems at the global scale, however, has lagged behind their counterparts for oceanic and atmospheric systems, largely because the unique challenges associated with the tremendous diversity and complexity of terrestrial ecosystems. There are 8 major types of terrestrial ecosystem: tropical rain forest, savannas, deserts, temperate grassland, deciduous forest, coniferous forest, tundra, and chaparral. The carbon cycle is an important mechanism in the coupling of terrestrial ecosystems with climate through biological fluxes of CO2. The influence of terrestrial ecosystems on atmospheric CO2 can be modeled via several means at different timescales. Important processes include plant dynamics, change in land use, as well as ecosystem biogeography. Over the past several decades, many terrestrial ecosystem models (see the 'Model developments' section) have been developed to understand the interactions between terrestrial carbon storage and CO2 concentration in the atmosphere, as well as the consequences of these interactions. Early TECMs generally adapted simple box-flow exchange models, in which photosynthetic CO2 uptake and respiratory CO2 release are simulated in an empirical manner with a small number of vegetation and soil carbon pools. Demands on kinds and amount of information required from global TECMs have grown. Recently, along with the rapid development of parallel computing, spatially explicit TECMs with detailed process based representations of carbon dynamics become attractive, because those models can readily incorporate a variety of additional ecosystem processes (such as dispersal, establishment, growth, mortality etc.) and environmental factors (such as landscape position, pest populations, disturbances, resource manipulations, etc.), and provide information to frame policy options for climate change impact
Executive functions, impulsivity, and inhibitory control in adolescents: A structural equation model
Fino, Emanuele; Melogno, Sergio; Iliceto, Paolo; D’Aliesio, Sara; Pinto, Maria Antonietta; Candilera, Gabriella; Sabatello, Ugo
2014-01-01
Background. Adolescence represents a critical period for brain development, addressed by neurodevelopmental models to frontal, subcortical-limbic, and striatal activation, a pattern associated with rise of impulsivity and deficits in inhibitory control. The present study aimed at studying the association between self-report measures of impulsivity and inhibitory control with executive function in adolescents, employing structural equation modeling. Method. Tests were administered to 434 high ...
How Can Peer Group Influence the Behavior of Adolescents: Explanatory Model
Tomé, Gina; Matos, Margarida Gaspar de; Simões, Celeste; Camacho, Inês; AlvesDiniz, José
2012-01-01
The current work aims to study both the peer group and family influence on adolescent behaviour. In order to achieve the aforementioned objective, an explanatory model based on the Structural Equations Modelling (SEM)was proposed. The sample used was the group of adolescents that participated in the Portuguese survey of the European study Health Behaviour in School-aged Children (HBSC). The Portuguese survey included students from grades 6, 8 and 10 within the public education system, with an...
Farmer, Thomas W.; Hamm, Jill V.; Lane, Kathleen L.; Lee, David; Sutherland, Kevin S.; Hall, Cristin M.; Murray, Robert A.
2013-01-01
Decades of research indicate that many early adolescents are at risk for developing significant school adjustment problems in the academic, behavioral, and social domains during the transition to middle school. The Supporting Early Adolescent Learning and Social Success (SEALS) model has been developed as a professional development and…
Vieno, Alessio; Nation, Maury; Pastore, Massimiliano; Santinello, Massimo
2009-01-01
This study used data collected from a sample of 840 Italian adolescents (418 boys; M age = 12.58) and their parents (657 mothers; M age = 43.78) to explore the relations between parenting, adolescent self-disclosure, and antisocial behavior. In the hypothesized model, parenting practices (e.g., parental monitoring and control) have direct effects…
Modeling groundwater flow on massively parallel computers
Energy Technology Data Exchange (ETDEWEB)
Ashby, S.F.; Falgout, R.D.; Fogwell, T.W.; Tompson, A.F.B.
1994-12-31
The authors will explore the numerical simulation of groundwater flow in three-dimensional heterogeneous porous media. An interdisciplinary team of mathematicians, computer scientists, hydrologists, and environmental engineers is developing a sophisticated simulation code for use on workstation clusters and MPPs. To date, they have concentrated on modeling flow in the saturated zone (single phase), which requires the solution of a large linear system. they will discuss their implementation of preconditioned conjugate gradient solvers. The preconditioners under consideration include simple diagonal scaling, s-step Jacobi, adaptive Chebyshev polynomial preconditioning, and multigrid. They will present some preliminary numerical results, including simulations of groundwater flow at the LLNL site. They also will demonstrate the code`s scalability.
Computational Granular Dynamics Models and Algorithms
Pöschel, Thorsten
2005-01-01
Computer simulations not only belong to the most important methods for the theoretical investigation of granular materials, but also provide the tools that have enabled much of the expanding research by physicists and engineers. The present book is intended to serve as an introduction to the application of numerical methods to systems of granular particles. Accordingly, emphasis is placed on a general understanding of the subject rather than on the presentation of the latest advances in numerical algorithms. Although a basic knowledge of C++ is needed for the understanding of the numerical methods and algorithms in the book, it avoids usage of elegant but complicated algorithms to remain accessible for those who prefer to use a different programming language. While the book focuses more on models than on the physics of granular material, many applications to real systems are presented.
Computational modeling of a forward lunge
DEFF Research Database (Denmark)
Eriksen, Tine Alkjær; Wieland, Maja Rose; Andersen, Michael Skipper;
2012-01-01
This study investigated the function of the cruciate ligaments during a forward lunge movement. The mechanical roles of the anterior and posterior cruciate ligament (ACL, PCL) during sagittal plane movements, such as forward lunging, are unclear. A forward lunge movement contains a knee joint...... flexion and extension that is controlled by the quadriceps muscle. The contraction of the quadriceps can cause anterior tibial translation, which may strain the ACL at knee joint positions close to full extension. However, recent findings suggest that it is the PCL rather than the ACL which is strained...... during forward lunging. Thus, the purpose of the present study was to establish a musculoskeletal model of the forward lunge to computationally investigate the complete mechanical force equilibrium of the tibia during the movement to examine the loading pattern of the cruciate ligaments. A healthy female...
Computational model for protein unfolding simulation
Tian, Xu-Hong; Zheng, Ye-Han; Jiao, Xiong; Liu, Cai-Xing; Chang, Shan
2011-06-01
The protein folding problem is one of the fundamental and important questions in molecular biology. However, the all-atom molecular dynamics studies of protein folding and unfolding are still computationally expensive and severely limited by the time scale of simulation. In this paper, a simple and fast protein unfolding method is proposed based on the conformational stability analyses and structure modeling. In this method, two structure-based conditions are considered to identify the unstable regions of proteins during the unfolding processes. The protein unfolding trajectories are mimicked through iterative structure modeling according to conformational stability analyses. Two proteins, chymotrypsin inhibitor 2 (CI2) and α -spectrin SH3 domain (SH3) were simulated by this method. Their unfolding pathways are consistent with the previous molecular dynamics simulations. Furthermore, the transition states of the two proteins were identified in unfolding processes and the theoretical Φ values of these transition states showed significant correlations with the experimental data (the correlation coefficients are >0.8). The results indicate that this method is effective in studying protein unfolding. Moreover, we analyzed and discussed the influence of parameters on the unfolding simulation. This simple coarse-grained model may provide a general and fast approach for the mechanism studies of protein folding.
Computational model of heterogeneous heating in melanin
Kellicker, Jason; DiMarzio, Charles A.; Kowalski, Gregory J.
2015-03-01
Melanin particles often present as an aggregate of smaller melanin pigment granules and have a heterogeneous surface morphology. When irradiated with light within the absorption spectrum of melanin, these heterogeneities produce measurable concentrations of the electric field that result in temperature gradients from thermal effects that are not seen with spherical or ellipsoidal modeling of melanin. Modeling melanin without taking into consideration the heterogeneous surface morphology yields results that underestimate the strongest signals or over{estimate their spatial extent. We present a new technique to image phase changes induced by heating using a computational model of melanin that exhibits these surface heterogeneities. From this analysis, we demonstrate the heterogeneous energy absorption and resulting heating that occurs at the surface of the melanin granule that is consistent with three{photon absorption. Using the three{photon dluorescence as a beacon, we propose a method for detecting the extents of the melanin granule using photothermal microscopy to measure the phase changes resulting from the heating of the melanin.
Computational Process Modeling for Additive Manufacturing (OSU)
Bagg, Stacey; Zhang, Wei
2015-01-01
Powder-Bed Additive Manufacturing (AM) through Direct Metal Laser Sintering (DMLS) or Selective Laser Melting (SLM) is being used by NASA and the Aerospace industry to "print" parts that traditionally are very complex, high cost, or long schedule lead items. The process spreads a thin layer of metal powder over a build platform, then melts the powder in a series of welds in a desired shape. The next layer of powder is applied, and the process is repeated until layer-by-layer, a very complex part can be built. This reduces cost and schedule by eliminating very complex tooling and processes traditionally used in aerospace component manufacturing. To use the process to print end-use items, NASA seeks to understand SLM material well enough to develop a method of qualifying parts for space flight operation. Traditionally, a new material process takes many years and high investment to generate statistical databases and experiential knowledge, but computational modeling can truncate the schedule and cost -many experiments can be run quickly in a model, which would take years and a high material cost to run empirically. This project seeks to optimize material build parameters with reduced time and cost through modeling.
Energy Technology Data Exchange (ETDEWEB)
Cummings, P. T.
2010-02-08
This document reports the outcomes of the Computational Nanoscience Project, "Integrated Multiscale Modeling of Molecular Computing Devices". It includes a list of participants and publications arising from the research supported.
Gravothermal Star Clusters - Theory and Computer Modelling
Spurzem, Rainer
2010-11-01
In the George Darwin lecture, delivered to the British Royal Astronomical Society in 1960 by Viktor A. Ambartsumian he wrote on the evolution of stellar systems that it can be described by the "dynamic evolution of a gravitating gas" complemented by "a statistical description of the changes in the physical states of stars". This talk will show how this physical concept has inspired theoretical modeling of star clusters in the following decades up to the present day. The application of principles of thermodynamics shows, as Ambartsumian argued in his 1960 lecture, that there is no stable state of equilibrium of a gravitating star cluster. The trend to local thermodynamic equilibrium is always disturbed by escaping stars (Ambartsumian), as well as by gravothermal and gravogyro instabilities, as it was detected later. Here the state-of-the-art of modeling the evolution of dense stellar systems based on principles of thermodynamics and statistical mechanics (Fokker-Planck approximation) will be reviewed. Recent progress including rotation and internal correlations (primordial binaries) is presented. The models have also very successfully been used to study dense star clusters around massive black holes in galactic nuclei and even (in a few cases) relativistic supermassive dense objects in centres of galaxies (here again briefly touching one of the many research fields of V.A. Ambartsumian). For the modern present time of high-speed supercomputing, where we are tackling direct N-body simulations of star clusters, we will show that such direct modeling supports and proves the concept of the statistical models based on the Fokker-Planck theory, and that both theoretical concepts and direct computer simulations are necessary to support each other and make scientific progress in the study of star cluster evolution.
A computational learning model for metrical phonology.
Dresher, B E; Kaye, J D
1990-02-01
One of the major challenges to linguistic theory is the solution of what has been termed the "projection problem". Simply put, linguistics must account for the fact that starting from a data base that is both unsystematic and relatively small, a human child is capable of constructing a grammar that mirrors, for all intents and purposes, the adult system. In this article we shall address ourselves to the question of the learnability of a postulated subsystem of phonological structure: the stress system. We shall describe a computer program which is designed to acquire this subpart of linguistic structure. Our approach follows the "principles and parameters" model of Chomsky (1981a, b). This model is particularly interesting from both a computational point of view and with respect to the development of learning theories. We encode the relevant aspects of universal grammar (UG)--those aspects of linguistic structure that are presumed innate and thus present in every linguistic system. The learning process consists of fixing a number of parameters which have been shown to underlie stress systems and which should, in principle, lead the learner to the postulation of the system from which the primary linguistic data (i.e., the input to the learner) is drawn. We go on to explore certain formal and substantive properties of this learning system. Questions such as cross-parameter dependencies, determinism, subsets, and incremental versus all-at-once learning are raised and discussed in the article. The issues raised by this study provide another perspective on the formal structure of stress systems and the learnability of parameter systems in general. PMID:2311355
An Integrated Model of Suicidal Ideation in Transcultural Populations of Chinese Adolescents.
Leung, Cyrus L K; Kwok, Sylvia Y C L; Ling, Chloe C Y
2016-07-01
This study tested the model of suicidal ideation, incorporating family and personal factors to predict suicidal ideation with hopelessness as a mediating factor in the Hong Kong sample, to a sample in Shanghai. Using MGSEM, the study aims to investigate the personal correlates and the family correlates of suicidal ideation in Hong Kong and Shanghai adolescents. We integrated the family ecological and diathesis-stress-hopelessness models of suicidal ideation in connecting the correlates. A cross-sectional design was used. The full model achieved metric invariance and partial path-loading invariance. Family functioning and social problem solving negatively predicted hopelessness or suicidal ideation in both the Hong Kong and Shanghai adolescents. The results supported an integrative approach in facilitating parent-adolescent communication and strengthening family functioning, and reducing the use of negative social problem-solving styles in adolescent suicide prevention. PMID:26308835
Walton, Maureen A.; Bohnert, Kipling; Resko, Stella; Barry, Kristen T.; Chermack, Stephen T.; Zucker, Robert A.; Zimmerman, Marc A.; Booth, Brenda M.; Blow, Frederic C.
2013-01-01
Aims This paper describes outcomes from a randomized controlled trial examining the efficacy of brief interventions delivered by a computer (CBI) or therapist (TBI) among adolescents in urban primary care clinics. Methods Patients (ages 12–18) self-administered a computer survey. Adolescents reporting past year cannabis use completed a baseline survey and were randomized to control, CBI or TBI, with primary (cannabis use, cannabis related consequences-CC) and secondary outcomes [alcohol use, other drug use (illicit and non-medical prescription drugs), and driving under the influence of cannabis (DUI)] assessed at 3, 6, and 12 months. Results 1416 adolescents were surveyed; 328 reported past year cannabis use and were randomized. Comparisons of the CBI relative to control showed that at 3 months the group by time interaction (GxT) was significant for other drug use and CC, but not for cannabis use, alcohol use, or DUI; at 6 months, the GxT interaction was significant for other drug use but not for cannabis use, alcohol use, or CC. For analyses comparing the TBI to control, at 3 months the GxT interaction was significant for DUI, but not significant for cannabis use, alcohol use, or CC; at 6 months, the GxT interaction was not significant for any variable. No significant intervention effects were observed at 12 months. Conclusion Among adolescent cannabis users presenting to primary care, a CBI decreased cannabis related problems and other drug use and a TBI decreased cannabis DUI in the short-term. Additional boosters may be necessary to enhance these reductions over time. PMID:23711998
Ennett, Susan T; Jackson, Christine; Cole, Veronica T; Haws, Susan; Foshee, Vangie A; Reyes, Heathe Luz McNaughton; Burns, Alison Reimuller; Cox, Melissa J; Cai, Li
2016-02-01
We assessed a multidimensional model of parent alcohol socialization in which key socialization factors were considered simultaneously to identify combinations of factors that increase or decrease risk for development of adolescent alcohol misuse. Of interest was the interplay between putative risk and protective factors, such as whether the typically detrimental effects on youth drinking of parenting practices tolerant of some adolescent alcohol use are mitigated by an effective overall approach to parenting and parental modeling of modest alcohol use. The sample included 1,530 adolescents and their mothers; adolescents' mean age was 13.0 (SD = .99) at the initial assessment. Latent profile analysis was conducted of mothers' reports of their attitude toward teen drinking, alcohol-specific parenting practices, parental alcohol use and problem use, and overall approach to parenting. The profiles were used to predict trajectories of adolescent alcohol misuse from early to middle adolescence. Four profiles were identified: 2 profiles reflected conservative alcohol-specific parenting practices and 2 reflected alcohol-tolerant practices, all in the context of other attributes. Alcohol misuse accelerated more rapidly from Grade 6 through 10 in the 2 alcohol-tolerant compared with conservative profiles. Results suggest that maternal tolerance of some youth alcohol use, even in the presence of dimensions of an effective parenting style and low parental alcohol use and problem use, is not an effective strategy for reducing risky adolescent alcohol use. (PsycINFO Database Record
Directory of Open Access Journals (Sweden)
Cheryl M. McCormick
2015-02-01
Full Text Available Studies in animal models generate and test hypotheses regarding developmental stage-specific vulnerability that might inform research questions about human development. In both rats and humans, peer relationships are qualitatively different in adolescence than at other stages of development, and social experiences in adolescence are considered important determinants of adult social function. This review describes our adolescent rat social instability stress model and the long-lasting effects social instability has on social behaviour in adulthood as well as the possible neural underpinnings. Effects of other adolescent social stress experiences in rats on social behaviours in adulthood also are reviewed. We discuss the role of hypothalamic–pituitary–adrenal (HPA function and glucocorticoid release in conferring differential susceptibility to social experiences in adolescents compared to adults. We propose that although differential perception of social experiences rather than immature HPA function may underlie the heightened vulnerability of adolescents to social instability, the changes in the trajectory of brain development and resultant social deficits likely are mediated by the heightened glucocorticoid release in response to repeated social stressors in adolescence compared to in adulthood.
Performance of Air Pollution Models on Massively Parallel Computers
DEFF Research Database (Denmark)
Brown, John; Hansen, Per Christian; Wasniewski, Jerzy;
1996-01-01
To compare the performance and use of three massively parallel SIMD computers, we implemented a large air pollution model on the computers. Using a realistic large-scale model, we gain detailed insight about the performance of the three computers when used to solve large-scale scientific problems...
A Granular Computing Model Based on Tolerance relation
Institute of Scientific and Technical Information of China (English)
WANG Guo-yin; HU Feng; HUANG Hai; WU Yu
2005-01-01
Granular computing is a new intelligent computing theory based on partition of problem concepts. It is an important problem in Rough Set theory to process incomplete information systems directly. In this paper, a granular computing model based on tolerance relation for processing incomplete information systems is developed. Furthermore, a criteria condition for attribution necessity is proposed in this model.
Computational modeling of acute myocardial infarction.
Sáez, P; Kuhl, E
2016-01-01
Myocardial infarction, commonly known as heart attack, is caused by reduced blood supply and damages the heart muscle because of a lack of oxygen. Myocardial infarction initiates a cascade of biochemical and mechanical events. In the early stages, cardiomyocytes death, wall thinning, collagen degradation, and ventricular dilation are the immediate consequences of myocardial infarction. In the later stages, collagenous scar formation in the infarcted zone and hypertrophy of the non-infarcted zone are auto-regulatory mechanisms to partly correct for these events. Here we propose a computational model for the short-term adaptation after myocardial infarction using the continuum theory of multiplicative growth. Our model captures the effects of cell death initiating wall thinning, and collagen degradation initiating ventricular dilation. Our simulations agree well with clinical observations in early myocardial infarction. They represent a first step toward simulating the progression of myocardial infarction with the ultimate goal to predict the propensity toward heart failure as a function of infarct intensity, location, and size. PMID:26583449
Computational Modeling of Biological Systems From Molecules to Pathways
2012-01-01
Computational modeling is emerging as a powerful new approach for studying and manipulating biological systems. Many diverse methods have been developed to model, visualize, and rationally alter these systems at various length scales, from atomic resolution to the level of cellular pathways. Processes taking place at larger time and length scales, such as molecular evolution, have also greatly benefited from new breeds of computational approaches. Computational Modeling of Biological Systems: From Molecules to Pathways provides an overview of established computational methods for the modeling of biologically and medically relevant systems. It is suitable for researchers and professionals working in the fields of biophysics, computational biology, systems biology, and molecular medicine.
AIR INGRESS ANALYSIS: COMPUTATIONAL FLUID DYNAMIC MODELS
International Nuclear Information System (INIS)
The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena Identification and Ranking Studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the in-the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of the lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to the release of fission products into the confinement, which could be detrimental to a reactor safety. Computational fluid dynamic model developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional and three-dimensional CFD results for the quantitative assessment of the air ingress phenomena. A portion of results of the density-driven stratified flow in the inlet pipe will be compared with results of the experimental results.
Entropy generation in a model of reversible computation
D. De Falco; Tamascelli, D.
2006-01-01
We present a model in which, due to the quantum nature of the signals controlling the implementation time of successive unitary computational steps, \\emph{physical} irreversibility appears in the execution of a \\emph{logically} reversible computation.
A semantic-web approach for modeling computing infrastructures
M. Ghijsen; J. van der Ham; P. Grosso; C. Dumitru; H. Zhu; Z. Zhao; C. de Laat
2013-01-01
This paper describes our approach to modeling computing infrastructures. Our main contribution is the Infrastructure and Network Description Language (INDL) ontology. The aim of INDL is to provide technology independent descriptions of computing infrastructures, including the physical resources as w
Penjadwalan Resource Pada Cloud Computing Menggunakan Model Integer Programming
Arlita, Nazly
2015-01-01
Cloud computing isn’t popular yet, but its development is increadibly. Cloud computing is being used because of the resource limitations as a contraints that blocks computation activities. This research purpose to obtain minimum cost in cloud computing service by using binary integer programming models. The service applying infrastructure as a service (IaaS) where virtualization machine being to user to use cloud computing . Optimization of this research showing which server deserves selecte...
Horticulture for Secondary Level Handicapped Adolescents: The Cherokee County Model.
Frith, Greg H.; And Others
1981-01-01
The Cherokee County (Alabama) horticulture training program provides 40 mildly mentally retarded adolescents with vocational training in a marketable skills. The broad spectrum of vocational skills makes horticulture ideal for the handicapped. (DB)
Modeling the growth of fingerprints improves matching for adolescents
Gottschlich, Carsten; Lorenz, Robert; Bernhardt, Stefanie; Hantschel, Michael; Munk, Axel
2010-01-01
We study the effect of growth on the fingerprints of adolescents, based on which we suggest a simple method to adjust for growth when trying to recover a juvenile's fingerprint in a database years later. Based on longitudinal data sets in juveniles' criminal records, we show that growth essentially leads to an isotropic rescaling, so that we can use the strong correlation between growth in stature and limbs to model the growth of fingerprints proportional to stature growth as documented in growth charts. The proposed rescaling leads to a 72% reduction of the distances between corresponding minutiae for the data set analyzed. These findings were corroborated by several verification tests. In an identification test on a database containing 3.25 million right index fingers at the Federal Criminal Police Office of Germany, the identification error rate of 20.8% was reduced to 2.1% by rescaling. The presented method is of striking simplicity and can easily be integrated into existing automated fingerprint identifi...
Computational Models of Spreadsheet Development: Basis for Educational Approaches
Hodnigg, Karin; Mittermeir, Roland T
2008-01-01
Among the multiple causes of high error rates in spreadsheets, lack of proper training and of deep understanding of the computational model upon which spreadsheet computations rest might not be the least issue. The paper addresses this problem by presenting a didactical model focussing on cell interaction, thus exceeding the atomicity of cell computations. The approach is motivated by an investigation how different spreadsheet systems handle certain computational issues implied from moving cells, copy-paste operations, or recursion.
Kim, Min Jung; Tajima, Emiko A.; Herrenkohl, Todd I.; Huang, Bu
2009-01-01
This article examines whether running away from home mediates the link between child maltreatment and later delinquency and victimization in adolescence. Specifically, the authors tested the hypothesis that childhood physical and psychological abuse increase the risk of a child's running away from home by the time of adolescence. Running away from home is, in turn, hypothesized to increase the risk of delinquency and victimization. Childhood sexual abuse, modeled independently of physical and...
Ennett, Susan T.; Jackson, Christine; Cole, Veronica T.; Haws, Susan; Foshee, Vangie A.; Reyes, Heathe Luz McNaughton; Burns, Alison Reimuller; Cox, Melissa J.; Cai, Li
2015-01-01
We assessed a multidimensional model of parent alcohol socialization in which key socialization factors were considered simultaneously to identify combinations of factors that increase or decrease risk for development of adolescent alcohol misuse. Of interest was the interplay between putative risk and protective factors, such as whether the typically detrimental effects on youth drinking of parenting practices tolerant of some adolescent alcohol use are mitigated by an effective overall appr...
Elements of matrix modeling and computing with Matlab
White, Robert E
2006-01-01
As discrete models and computing have become more common, there is a need to study matrix computation and numerical linear algebra. Encompassing a diverse mathematical core, Elements of Matrix Modeling and Computing with MATLAB examines a variety of applications and their modeling processes, showing you how to develop matrix models and solve algebraic systems. Emphasizing practical skills, it creates a bridge from problems with two and three variables to more realistic problems that have additional variables. Elements of Matrix Modeling and Computing with MATLAB focuses on seven basic applicat
Lindenmayer systems as a model of computations
Ozhigov, Y I
1998-01-01
LS is a particular type of computational processes simulating living tissue. They use an unlimited branching process arising from the simultaneous substitutions of some words instead of letters in some initial word. This combines the properties of cellular automata and grammars. It is proved that 1) The set of languages, computed in a polynomial time on such LS that all replacing words are not empty, is exactly NP- languages. 2) The set of languages, computed in a polynomial time on arbitrary LS, contains the polynomial hierarchy. 3) The set of languages, computed in a polynomial time on a nondeterministic version of LS, strictly contains the set of languages, computed in a polynomial time on Turing Machines with a space complexity $n^a$, where $a$ is positive integer. In particular, the last two results mean that Lindenmayer systems may be even more powerful tool of computations than nondeterministic Turing Machine.
Lindenmayer systems as a model of computations
Ozhigov, Yuri
1998-01-01
LS is a particular type of computational processes simulating living tissue. They use an unlimited branching process arising from the simultaneous substitutions of some words instead of letters in some initial word. This combines the properties of cellular automata and grammars. It is proved that 1) The set of languages, computed in a polynomial time on such LS that all replacing words are not empty, is exactly NP- languages. 2) The set of languages, computed in a polynomial time on arbitrary...
Structural computational modeling of RNA aptamers.
Xu, Xiaojun; Dickey, David D; Chen, Shi-Jie; Giangrande, Paloma H
2016-07-01
RNA aptamers represent an emerging class of biologics that can be easily adapted for personalized and precision medicine. Several therapeutic aptamers with desirable binding and functional properties have been developed and evaluated in preclinical studies over the past 25years. However, for the majority of these aptamers, their clinical potential has yet to be realized. A significant hurdle to the clinical adoption of this novel class of biologicals is the limited information on their secondary and tertiary structure. Knowledge of the RNA's structure would greatly facilitate and expedite the post-selection optimization steps required for translation, including truncation (to reduce costs of manufacturing), chemical modification (to enhance stability and improve safety) and chemical conjugation (to improve drug properties for combinatorial therapy). Here we describe a structural computational modeling methodology that when coupled to a standard functional assay, can be used to determine key sequence and structural motifs of an RNA aptamer. We applied this methodology to enable the truncation of an aptamer to prostate specific membrane antigen (PSMA) with great potential for targeted therapy that had failed previous truncation attempts. This methodology can be easily applied to optimize other aptamers with therapeutic potential. PMID:26972787
Review of computational thermal-hydraulic modeling
Energy Technology Data Exchange (ETDEWEB)
Keefer, R.H.; Keeton, L.W.
1995-12-31
Corrosion of heat transfer tubing in nuclear steam generators has been a persistent problem in the power generation industry, assuming many different forms over the years depending on chemistry and operating conditions. Whatever the corrosion mechanism, a fundamental understanding of the process is essential to establish effective management strategies. To gain this fundamental understanding requires an integrated investigative approach that merges technology from many diverse scientific disciplines. An important aspect of an integrated approach is characterization of the corrosive environment at high temperature. This begins with a thorough understanding of local thermal-hydraulic conditions, since they affect deposit formation, chemical concentration, and ultimately corrosion. Computational Fluid Dynamics (CFD) can and should play an important role in characterizing the thermal-hydraulic environment and in predicting the consequences of that environment,. The evolution of CFD technology now allows accurate calculation of steam generator thermal-hydraulic conditions and the resulting sludge deposit profiles. Similar calculations are also possible for model boilers, so that tests can be designed to be prototypic of the heat exchanger environment they are supposed to simulate. This paper illustrates the utility of CFD technology by way of examples in each of these two areas. This technology can be further extended to produce more detailed local calculations of the chemical environment in support plate crevices, beneath thick deposits on tubes, and deep in tubesheet sludge piles. Knowledge of this local chemical environment will provide the foundation for development of mechanistic corrosion models, which can be used to optimize inspection and cleaning schedules and focus the search for a viable fix.
Modelling, abstraction, and computation in systems biology: A view from computer science.
Melham, Tom
2013-04-01
Systems biology is centrally engaged with computational modelling across multiple scales and at many levels of abstraction. Formal modelling, precise and formalised abstraction relationships, and computation also lie at the heart of computer science--and over the past decade a growing number of computer scientists have been bringing their discipline's core intellectual and computational tools to bear on biology in fascinating new ways. This paper explores some of the apparent points of contact between the two fields, in the context of a multi-disciplinary discussion on conceptual foundations of systems biology.
Predictive Capability Maturity Model for computational modeling and simulation.
Energy Technology Data Exchange (ETDEWEB)
Oberkampf, William Louis; Trucano, Timothy Guy; Pilch, Martin M.
2007-10-01
The Predictive Capability Maturity Model (PCMM) is a new model that can be used to assess the level of maturity of computational modeling and simulation (M&S) efforts. The development of the model is based on both the authors experience and their analysis of similar investigations in the past. The perspective taken in this report is one of judging the usefulness of a predictive capability that relies on the numerical solution to partial differential equations to better inform and improve decision making. The review of past investigations, such as the Software Engineering Institute's Capability Maturity Model Integration and the National Aeronautics and Space Administration and Department of Defense Technology Readiness Levels, indicates that a more restricted, more interpretable method is needed to assess the maturity of an M&S effort. The PCMM addresses six contributing elements to M&S: (1) representation and geometric fidelity, (2) physics and material model fidelity, (3) code verification, (4) solution verification, (5) model validation, and (6) uncertainty quantification and sensitivity analysis. For each of these elements, attributes are identified that characterize four increasing levels of maturity. Importantly, the PCMM is a structured method for assessing the maturity of an M&S effort that is directed toward an engineering application of interest. The PCMM does not assess whether the M&S effort, the accuracy of the predictions, or the performance of the engineering system satisfies or does not satisfy specified application requirements.
Examining a social reaction model in the prediction of adolescent alcohol use.
Litt, Dana M; Lewis, Melissa A
2016-09-01
The prototype willingness model (PWM; Gerrard et al., 2008) is a modified dual-processing model designed to improve the predictive value of existing health risk behavior by suggesting that there are two pathways to health risk behaviors: a reasoned path that is mediated by behavioral intention and a social reaction path that is mediated by behavioral willingness. Although there is evidence supporting the social reaction path to risk behavior among adolescents, most of this work has focused on specific components of the pathway such as prototypes or willingness rather than looking at the entire social reaction pathway as a whole. As such, the primary goal of the present study was to determine whether the social reaction pathway has acceptable fit for a sample of adolescents using a longitudinal design. Results from 835 adolescents support the social reaction pathway of the PWM model when applied to adolescent alcohol use. Specifically, prototypes, perceived vulnerability, and norms predicted willingness to drink, which in turn predicted drinking behavior (drinks per week and peak number of drinks) over a period of 12months. As such, these findings suggest that the social reaction pathway of the PWM is applicable to adolescent drinkers, meaning that adolescent drinking behavior is based on a less planned and socially based decision process. PMID:27155242
MEMBRANE COMPUTING AS THE PARADIGM FOR MODELING SYSTEMS BIOLOGY
Directory of Open Access Journals (Sweden)
Ravie Chandren Muniyandi
2013-01-01
Full Text Available Membrane computing is a field in computer science that is inspired from the structure and the processes of living cells and is being considered as an alternative in solving the limitations in conventional mathematical approaches by taking into consideration its essential features that are of interest for research in systems biology. Advancements in computability make it feasible to handle huge volumes of data in biology and propose a new and better approach using a discreet computer science model, such as membrane computing. In this respect, membrane-computing abilities, to enhance the understanding of the system level of biological systems, have been explored. This study discusses experiences in applying membrane computing in modeling biological systems as well as possibilities of incorporating membrane computing into other computer science paradigms to enhance the use of membrane computing in systems biology. Experiences in modeling aspects of systems biology with membrane computing demonstrate additional advantages and possibilities compared with conventional methods. However, they are not yet used widely to model or simulate biological processes or systems. A general framework of modeling and verifying biological systems using membrane computing is essential as a guideline for biologists in their research in systems biology.
Learning Anatomy: Do New Computer Models Improve Spatial Understanding?
Garg, Amit; Norman, Geoff; Spero, Lawrence; Taylor, Ian
1999-01-01
Assesses desktop-computer models that rotate in virtual three-dimensional space. Compares spatial learning with a computer carpal-bone model horizontally rotating at 10-degree views with the same model rotating at 90-degree views. (Author/CCM)
Kiang, Lisa; Witkow, Melissa R; Thompson, Taylor L
2016-07-01
The model minority image is a common and pervasive stereotype that Asian American adolescents must navigate. Using multiwave data from 159 adolescents from Asian American backgrounds (mean age at initial recruitment = 15.03, SD = .92; 60 % female; 74 % US-born), the current study targeted unexplored aspects of the model minority experience in conjunction with more traditionally measured experiences of negative discrimination. When examining normative changes, perceptions of model minority stereotyping increased over the high school years while perceptions of discrimination decreased. Both experiences were not associated with each other, suggesting independent forms of social interactions. Model minority stereotyping generally promoted academic and socioemotional adjustment, whereas discrimination hindered outcomes. Moreover, in terms of academic adjustment, the model minority stereotype appears to protect against the detrimental effect of discrimination. Implications of the complex duality of adolescents' social interactions are discussed.
Kim, Young-Mi; Neff, James Alan
2010-01-01
A model incorporating the direct and indirect effects of parental monitoring on adolescent alcohol use was evaluated by applying structural equation modeling (SEM) techniques to data on 4,765 tenth-graders in the 2001 Monitoring the Future Study. Analyses indicated good fit of hypothesized measurement and structural models. Analyses supported both…
COMPUTER MODEL FOR ORGANIC FERTILIZER EVALUATION
Directory of Open Access Journals (Sweden)
Zdenko Lončarić
2009-12-01
seedlings with highest mass and leaf area are produced using growing media with pH close to 6 and with EC lower than 2 dSm-1. It could be concluded that conductivity approx. 3 dSm-1 has inhibitory effect on lettuce if pH is about 7 or higher. The computer model shows that raising pH and EC resulted in decreasing growth which could be expressed as increasing stress index. The lettuce height as a function of pH and EC is incorporated into the model as stress function showing increase of lettuce height by lowering EC from 4 to 1 dSm-1or pH from 7.4 to 6. The highest growing media index (8.1 was determined for mixture of composted pig manure and peat (1:1, and lowest (2.3 for composted horse manure and peat (1:2.
Role models and occupational ambitions of in-school male adolescents
Directory of Open Access Journals (Sweden)
Suhail Ahmad Azmi
2014-01-01
Full Text Available Background: A role model is perceived as worthy of imitation, their selection can indicate significant elements of psychosocial health and self-projection in adolescents. Patterns of behavior and lifestyle choices established during adolescence can have immediate and lasting effects on health. Materials and Methods: Cross-sectional study was undertaken in the schools of Aligarh, Uttar Pradesh, India. The sample frame was 2347, out of which a sample of 390 students was studied. Data collected were entered and analyzed by SPSS for Windows version 10%. Results: Majority (62.7% of adolescents revealed that their role models were Film Star (34.8% and their Teachers (27.9%, Parents (14.3%, Sportsman (12.0%. Politicians as the role models were opted by least proportion (1.2%. Desire of future occupation was Businessmen (27.9%, Doctor (18.6, and Engineer (14.4%. Conclusion: Nearly all adolescents had a role model. There is greater impact of cinema on the minds of adolescents, which resulted in choosing film actors as their role model. Aspiration of future occupation was not related to the characteristics of the role model.
The complete guide to blender graphics computer modeling and animation
Blain, John M
2014-01-01
Smoothly Leads Users into the Subject of Computer Graphics through the Blender GUIBlender, the free and open source 3D computer modeling and animation program, allows users to create and animate models and figures in scenes, compile feature movies, and interact with the models and create video games. Reflecting the latest version of Blender, The Complete Guide to Blender Graphics: Computer Modeling & Animation, 2nd Edition helps beginners learn the basics of computer animation using this versatile graphics program. This edition incorporates many new features of Blender, including developments
Adolescent male sexuality and heterosexual masculinity: a conceptual model and review.
Marsiglio, W
1988-01-01
Scant research attention has been given to understanding the social and psychological dimensions of adolescent male sexuality. This paper therefore integrates several major theoretical themes into a conceptual model to provide an interpretation of adolescent males' sexuality within the context of contemporary American society. The framework clarifies how the requirements of a traditional and narrow image of masculinity intersect with features of adolescence to help shape the sexual expectations and experiences of many young men today. Issues related to the negotiated, interpersonal, scripting process for initial sexual encounters are discussed. In that context, several factors affecting males' willingness to enact sexual scripts and the possible implications of incongruity between partners' scripting preferences are examined. Finally, current and future developments which may produce changes in adolescent males' sexual and reproductive consciousness and the scripting process are illustrated. PMID:12342679
Phan, Philippe; Mezghani, Neila; Aubin, Carl-Éric; de Guise, Jacques A.; Labelle, Hubert
2011-01-01
Adolescent idiopathic scoliosis (AIS) is a complex spinal deformity whose assessment and treatment present many challenges. Computer applications have been developed to assist clinicians. A literature review on computer applications used in AIS evaluation and treatment has been undertaken. The algorithms used, their accuracy and clinical usability were analyzed. Computer applications have been used to create new classifications for AIS based on 2D and 3D features, assess scoliosis severity or...
Computer modeling of a convective steam superheater
Trojan, Marcin
2015-03-01
Superheater is for generating superheated steam from the saturated steam from the evaporator outlet. In the case of pulverized coal fired boiler, a relatively small amount of ash causes problems with ash fouling on the heating surfaces, including the superheaters. In the convection pass of the boiler, the flue gas temperature is lower and ash deposits can be loose or sintered. Ash fouling not only reduces heat transfer from the flue gas to the steam, but also is the cause of a higher pressure drop on the flue gas flow path. In the case the pressure drop is greater than the power consumed by the fan increases. If the superheater surfaces are covered with ash than the steam temperature at the outlet of the superheater stages falls, and the flow rates of the water injected into attemperator should be reduced. There is also an increase in flue gas temperature after the different stages of the superheater. Consequently, this leads to a reduction in boiler efficiency. The paper presents the results of computational fluid dynamics simulations of the first stage superheater of both the boiler OP-210M using the commercial software. The temperature distributions of the steam and flue gas along the way they flow together with temperature of the tube walls and temperature of the ash deposits will be determined. The calculated steam temperature is compared with measurement results. Knowledge of these temperatures is of great practical importance because it allows to choose the grade of steel for a given superheater stage. Using the developed model of the superheater to determine its degree of ash fouling in the on-line mode one can control the activation frequency of steam sootblowers.
Computer modeling of a convective steam superheater
Directory of Open Access Journals (Sweden)
Trojan Marcin
2015-03-01
Full Text Available Superheater is for generating superheated steam from the saturated steam from the evaporator outlet. In the case of pulverized coal fired boiler, a relatively small amount of ash causes problems with ash fouling on the heating surfaces, including the superheaters. In the convection pass of the boiler, the flue gas temperature is lower and ash deposits can be loose or sintered. Ash fouling not only reduces heat transfer from the flue gas to the steam, but also is the cause of a higher pressure drop on the flue gas flow path. In the case the pressure drop is greater than the power consumed by the fan increases. If the superheater surfaces are covered with ash than the steam temperature at the outlet of the superheater stages falls, and the flow rates of the water injected into attemperator should be reduced. There is also an increase in flue gas temperature after the different stages of the superheater. Consequently, this leads to a reduction in boiler efficiency. The paper presents the results of computational fluid dynamics simulations of the first stage superheater of both the boiler OP-210M using the commercial software. The temperature distributions of the steam and flue gas along the way they flow together with temperature of the tube walls and temperature of the ash deposits will be determined. The calculated steam temperature is compared with measurement results. Knowledge of these temperatures is of great practical importance because it allows to choose the grade of steel for a given superheater stage. Using the developed model of the superheater to determine its degree of ash fouling in the on-line mode one can control the activation frequency of steam sootblowers.
Security Issues Model on Cloud Computing: A Case of Malaysia
Komeil Raisian; Jamaiah Yahaya
2015-01-01
By developing the cloud computing, viewpoint of many people regarding the infrastructure architectures, software distribution and improvement model changed significantly. Cloud computing associates with the pioneering deployment architecture, which could be done through grid calculating, effectiveness calculating and autonomic calculating. The fast transition towards that, has increased the worries regarding a critical issue for the effective transition of cloud computing. From the security v...
An Emotional Agent Model Based on Granular Computing
Directory of Open Access Journals (Sweden)
Jun Hu
2012-01-01
Full Text Available Affective computing has a very important significance for fulfilling intelligent information processing and harmonious communication between human being and computers. A new model for emotional agent is proposed in this paper to make agent have the ability of handling emotions, based on the granular computing theory and the traditional BDI agent model. Firstly, a new emotion knowledge base based on granular computing for emotion expression is presented in the model. Secondly, a new emotional reasoning algorithm based on granular computing is proposed. Thirdly, a new emotional agent model based on granular computing is presented. Finally, based on the model, an emotional agent for patient assistant in hospital is realized, experiment results show that it is efficient to handle simple emotions.
Performance Models for Split-execution Computing Systems
Energy Technology Data Exchange (ETDEWEB)
Humble, Travis S [ORNL; McCaskey, Alex [ORNL; Schrock, Jonathan [ORNL; Seddiqi, Hadayat [ORNL; Britt, Keith A [ORNL; Imam, Neena [ORNL
2016-01-01
Split-execution computing leverages the capabilities of multiple computational models to solve problems, but splitting program execution across different computational models incurs costs associated with the translation between domains. We analyze the performance of a split-execution computing system developed from conventional and quantum processing units (QPUs) by using behavioral models that track resource usage. We focus on asymmetric processing models built using conventional CPUs and a family of special-purpose QPUs that employ quantum computing principles. Our performance models account for the translation of a classical optimization problem into the physical representation required by the quantum processor while also accounting for hardware limitations and conventional processor speed and memory. We conclude that the bottleneck in this split-execution computing system lies at the quantum-classical interface and that the primary time cost is independent of quantum processor behavior.
A computationally tractable version of the collective model
Rowe, D J
2003-01-01
A computationally tractable version of the Bohr-Mottelson collective model is presented which makes it possible to diagonalize realistic collective models and obtain convergent results in relatively small appropriately chosen subspaces of the collective model Hilbert space. Special features of the proposed model is that it makes use of the beta wave functions given analytically by the softened-beta version of the Wilets-Jean model, proposed by Elliott et al., and a simple algorithm for comput...
Soft Computing Models in Industrial and Environmental Applications
Abraham, Ajith; Corchado, Emilio; 7th International Conference, SOCO’12
2013-01-01
This volume of Advances in Intelligent and Soft Computing contains accepted papers presented at SOCO 2012, held in the beautiful and historic city of Ostrava (Czech Republic), in September 2012. Soft computing represents a collection or set of computational techniques in machine learning, computer science and some engineering disciplines, which investigate, simulate, and analyze very complex issues and phenomena. After a through peer-review process, the SOCO 2012 International Program Committee selected 75 papers which are published in these conference proceedings, and represents an acceptance rate of 38%. In this relevant edition a special emphasis was put on the organization of special sessions. Three special sessions were organized related to relevant topics as: Soft computing models for Control Theory & Applications in Electrical Engineering, Soft computing models for biomedical signals and data processing and Advanced Soft Computing Methods in Computer Vision and Data Processing. The selecti...
Scaling predictive modeling in drug development with cloud computing.
Moghadam, Behrooz Torabi; Alvarsson, Jonathan; Holm, Marcus; Eklund, Martin; Carlsson, Lars; Spjuth, Ola
2015-01-26
Growing data sets with increased time for analysis is hampering predictive modeling in drug discovery. Model building can be carried out on high-performance computer clusters, but these can be expensive to purchase and maintain. We have evaluated ligand-based modeling on cloud computing resources where computations are parallelized and run on the Amazon Elastic Cloud. We trained models on open data sets of varying sizes for the end points logP and Ames mutagenicity and compare with model building parallelized on a traditional high-performance computing cluster. We show that while high-performance computing results in faster model building, the use of cloud computing resources is feasible for large data sets and scales well within cloud instances. An additional advantage of cloud computing is that the costs of predictive models can be easily quantified, and a choice can be made between speed and economy. The easy access to computational resources with no up-front investments makes cloud computing an attractive alternative for scientists, especially for those without access to a supercomputer, and our study shows that it enables cost-efficient modeling of large data sets on demand within reasonable time.
Resilient Quantum Computation Error Models and Thresholds
Knill, E H; Zurek, W H; Knill, Emanuel; Laflamme, Raymond; Zurek, Wojciech H.
1997-01-01
Recent research has demonstrated that quantum computers can solve certain types of problems substantially faster than the known classical algorithms. These problems include factoring integers and certain physics simulations. Practical quantum computation requires overcoming the problems of environmental noise and operational errors, problems which appear to be much more severe than in classical computation due to the inherent fragility of quantum superpositions involving many degrees of freedom. Here we show that arbitrarily accurate quantum computations are possible provided that the error per operation is below a threshold value. The result is obtained by combining quantum error-correction, fault tolerant state recovery, fault tolerant encoding of operations and concatenation. It holds under physically realistic assumptions on the errors.
Behavior computing modeling, analysis, mining and decision
2012-01-01
Includes six case studies on behavior applications Presents new techniques for capturing behavior characteristics in social media First dedicated source of references for the theory and applications of behavior informatics and behavior computing
Sticker DNA computer model--Part Ⅰ:Theory
Institute of Scientific and Technical Information of China (English)
XU Jin; DONG Yafei; WEI Xiaopeng
2004-01-01
Sticker model is one of the basic models in the DNA computer models. This model is coded with single-double stranded DNA molecules. It has the following advantages that the operations require no strands extension and use no enzymes; What's more, the materials are reusable. Therefore it arouses attention and interest of scientists in many fields. In this paper, we will systematically analyze the theories and applications of the model, summarize other scientists' contributions in this field, and propose our research results. This paper is the theoretical portion of the sticker model on DNA computer, which includes the introduction of the basic model of sticker computing. Firstly, we systematically introduce the basic theories of classic models about sticker computing; Secondly, we discuss the sticker system which is an abstract computing model based on the sticker model and formal languages; Finally, extend and perfect the model, and present two types of models that are more extensive in the applications and more perfect in the theory than the past models: one is the so-called k-bit sticker model, the other is full-message sticker DNA computing model.
The emerging role of cloud computing in molecular modelling.
Ebejer, Jean-Paul; Fulle, Simone; Morris, Garrett M; Finn, Paul W
2013-07-01
There is a growing recognition of the importance of cloud computing for large-scale and data-intensive applications. The distinguishing features of cloud computing and their relationship to other distributed computing paradigms are described, as are the strengths and weaknesses of the approach. We review the use made to date of cloud computing for molecular modelling projects and the availability of front ends for molecular modelling applications. Although the use of cloud computing technologies for molecular modelling is still in its infancy, we demonstrate its potential by presenting several case studies. Rapid growth can be expected as more applications become available and costs continue to fall; cloud computing can make a major contribution not just in terms of the availability of on-demand computing power, but could also spur innovation in the development of novel approaches that utilize that capacity in more effective ways.
Reduced order methods for modeling and computational reduction
Rozza, Gianluigi
2014-01-01
This monograph addresses the state of the art of reduced order methods for modeling and computational reduction of complex parametrized systems, governed by ordinary and/or partial differential equations, with a special emphasis on real time computing techniques and applications in computational mechanics, bioengineering and computer graphics. Several topics are covered, including: design, optimization, and control theory in real-time with applications in engineering; data assimilation, geometry registration, and parameter estimation with special attention to real-time computing in biomedical engineering and computational physics; real-time visualization of physics-based simulations in computer science; the treatment of high-dimensional problems in state space, physical space, or parameter space; the interactions between different model reduction and dimensionality reduction approaches; the development of general error estimation frameworks which take into account both model and discretization effects. This...
Los Alamos CCS (Center for Computer Security) formal computer security model
Energy Technology Data Exchange (ETDEWEB)
Dreicer, J.S.; Hunteman, W.J. (Los Alamos National Lab., NM (USA))
1989-01-01
This paper provides a brief presentation of the formal computer security model currently being developed at the Los Alamos Department of Energy (DOE) Center for Computer Security (CCS). The initial motivation for this effort was the need to provide a method by which DOE computer security policy implementation could be tested and verified. The actual analytical model was a result of the integration of current research in computer security and previous modeling and research experiences. The model is being developed to define a generic view of the computer and network security domains, to provide a theoretical basis for the design of a security model, and to address the limitations of present models. Formal mathematical models for computer security have been designed and developed in conjunction with attempts to build secure computer systems since the early 70's. The foundation of the Los Alamos DOE CCS model is a series of functionally dependent probability equations, relations, and expressions. The mathematical basis appears to be justified and is undergoing continued discrimination and evolution. We expect to apply the model to the discipline of the Bell-Lapadula abstract sets of objects and subjects. 5 refs.
User Behavior Trust Based Cloud Computing Access Control Model
Jiangcheng, Qin
2016-01-01
Context. With the development of computer software, hardware, and communication technologies, a new type of human-centered computing model, called Cloud Computing (CC) has been established as a commercial computer network service. However, the openness of CC brings huge security challenge to the identity-based access control system, as it not able to effectively prevent malicious users accessing; information security problems, system stability problems, and also the trust issues between cloud...
Integrated Multiscale Modeling of Molecular Computing Devices
Energy Technology Data Exchange (ETDEWEB)
Jerzy Bernholc
2011-02-03
photolithography will some day reach a miniaturization limit, forcing designers of Si-based electronics to pursue increased performance by other means. Any other alternative approach would have the unenviable task of matching the ability of Si technology to pack more than a billion interconnected and addressable devices on a chip the size of a thumbnail. Nevertheless, the prospects of developing alternative approaches to fabricate electronic devices have spurred an ever-increasing pace of fundamental research. One of the promising possibilities is molecular electronics (ME), self-assembled molecular-based electronic systems composed of single-molecule devices in ultra dense, ultra fast molecular-sized components. This project focused on developing accurate, reliable theoretical modeling capabilities for describing molecular electronics devices. The participants in the project are given in Table 1. The primary outcomes of this fundamental computational science grant are publications in the open scientific literature. As listed below, 62 papers have been published from this project. In addition, the research has also been the subject of more than 100 invited talks at conferences, including several plenary or keynote lectures. Many of the goals of the original proposal were completed. Specifically, the multi-disciplinary group developed a unique set of capabilities and tools for investigating electron transport in fabricated and self-assembled nanostructures at multiple length and time scales.
Pouly, Amaury; Graça, Daniel S
2012-01-01
\\emph{Are analog models of computations more powerful than classical models of computations?} From a series of recent papers, it is now clear that many realistic analog models of computations are provably equivalent to classical digital models of computations from a \\emph{computability} point of view. Take, for example, the probably most realistic model of analog computation, the General Purpose Analog Computer (GPAC) model from Claude Shannon, a model for Differential Analyzers, which are analog machines used from 1930s to early 1960s to solve various problems. It is now known that functions computable by Turing machines are provably exactly those that are computable by GPAC. This paper is about next step: understanding if this equivalence also holds at the \\emph{complexity} level. In this paper we show that the realistic models of analog computation -- namely the General Purpose Analog Computer (GPAC) -- can simulate Turing machines in a computationally efficient manner. More concretely we show that, modulo...
Georgiev, K.; Zlatev, Z.
2010-11-01
The Danish Eulerian Model (DEM) is an Eulerian model for studying the transport of air pollutants on large scale. Originally, the model was developed at the National Environmental Research Institute of Denmark. The model computational domain covers Europe and some neighbour parts belong to the Atlantic Ocean, Asia and Africa. If DEM model is to be applied by using fine grids, then its discretization leads to a huge computational problem. This implies that such a model as DEM must be run only on high-performance computer architectures. The implementation and tuning of such a complex large-scale model on each different computer is a non-trivial task. Here, some comparison results of running of this model on different kind of vector (CRAY C92A, Fujitsu, etc.), parallel computers with distributed memory (IBM SP, CRAY T3E, Beowulf clusters, Macintosh G4 clusters, etc.), parallel computers with shared memory (SGI Origin, SUN, etc.) and parallel computers with two levels of parallelism (IBM SMP, IBM BlueGene/P, clusters of multiprocessor nodes, etc.) will be presented. The main idea in the parallel version of DEM is domain partitioning approach. Discussions according to the effective use of the cache and hierarchical memories of the modern computers as well as the performance, speed-ups and efficiency achieved will be done. The parallel code of DEM, created by using MPI standard library, appears to be highly portable and shows good efficiency and scalability on different kind of vector and parallel computers. Some important applications of the computer model output are presented in short.
A qualitative model for computer-assisted instruction in cardiology.
Julen, N.; Siregar, P.; Sinteff, J. P.; Le Beux, P.
1998-01-01
CARDIOLAB is an interactive computational framework dedicated to teaching and computer-aided diagnosis in cardiology. The framework embodies models that simulate the heart's electrical activity. They constitute the core of a Computer-Assisted Instruction (CAI) program intended to teach, in a multimedia environment, the concepts underlying rhythmic disorders and cardiac diseases. The framework includes a qualitative model (QM) which is described in this paper. During simulation using QM, dynam...
A Computational Model of Crowds for Collective Intelligence
Prpic, John; Jackson, Piper; Nguyen, Thai
2014-01-01
In this work, we present a high-level computational model of IT-mediated crowds for collective intelligence. We introduce the Crowd Capital perspective as an organizational-level model of collective intelligence generation from IT-mediated crowds, and specify a computational system including agents, forms of IT, and organizational knowledge.
Python for Scientific Computing Education: Modeling of Queueing Systems
Directory of Open Access Journals (Sweden)
Vladimiras Dolgopolovas
2014-01-01
Full Text Available In this paper, we present the methodology for the introduction to scientific computing based on model-centered learning. We propose multiphase queueing systems as a basis for learning objects. We use Python and parallel programming for implementing the models and present the computer code and results of stochastic simulations.
Python for Scientific Computing Education: Modeling of Queueing Systems
Vladimiras Dolgopolovas; Valentina Dagienė; Saulius Minkevičius; Leonidas Sakalauskas
2014-01-01
In this paper, we present the methodology for the introduction to scientific computing based on model-centered learning. We propose multiphase queueing systems as a basis for learning objects. We use Python and parallel programming for implementing the models and present the computer code and results of stochastic simulations.
On the Computational Expressiveness of Model Transformation Languages
DEFF Research Database (Denmark)
Al-Sibahi, Ahmad Salim
2015-01-01
, it is not immediately obvious what their computational expressiveness is. In this paper we present an analysis that clarifies the computational expressiveness of a large number of model transformation languages. The analysis confirms the folklore for all model transformation languages, except the bidirectional ones...
Overview of ASC Capability Computing System Governance Model
Energy Technology Data Exchange (ETDEWEB)
Doebling, Scott W. [Los Alamos National Laboratory
2012-07-11
This document contains a description of the Advanced Simulation and Computing Program's Capability Computing System Governance Model. Objectives of the Governance Model are to ensure that the capability system resources are allocated on a priority-driven basis according to the Program requirements; and to utilize ASC Capability Systems for the large capability jobs for which they were designed and procured.
World Knowledge in Computational Models of Discourse Comprehension
Frank, Stefan L.; Koppen, Mathieu; Noordman, Leo G. M.; Vonk, Wietske
2008-01-01
Because higher level cognitive processes generally involve the use of world knowledge, computational models of these processes require the implementation of a knowledge base. This article identifies and discusses 4 strategies for dealing with world knowledge in computational models: disregarding world knowledge, "ad hoc" selection, extraction from…
A Psychoecological Model of Academic Performance among Hispanic Adolescents
Chun, Heejung; Dickson, Ginger
2011-01-01
Although the number of students who complete high school continues to rise, dramatic differences in school success remain across racial/ethnic groups. The current study addressed Hispanic adolescents' academic performance by investigating the relationships of parental involvement, culturally responsive teaching, sense of school belonging, and…
Ewing, E Stephanie Krauthamer; Diamond, Guy; Levy, Suzanne
2015-01-01
Attachment-Based Family Therapy (ABFT) is a manualized family-based intervention designed for working with depressed adolescents, including those at risk for suicide, and their families. It is an empirically informed and supported treatment. ABFT has its theoretical underpinnings in attachment theory and clinical roots in structural family therapy and emotion focused therapies. ABFT relies on a transactional model that aims to transform the quality of adolescent-parent attachment, as a means of providing the adolescent with a more secure relationship that can support them during challenging times generally, and the crises related to suicidal thinking and behavior, specifically. This article reviews: (1) the theoretical foundations of ABFT (attachment theory, models of emotional development); (2) the ABFT clinical model, including training and supervision factors; and (3) empirical support. PMID:25778674
Onset to First Alcohol Use in Early Adolescence: A Network Diffusion Model
Light, John M.; Greenan, Charlotte C.; Rusby, Julie C.; Nies, Kimberley M.; Snijders, Tom A.B.
2013-01-01
A novel version of Snijders’s stochastic actor-based modeling (SABM) framework is applied to model the diffusion of first alcohol use through middle school-wide longitudinal networks of early adolescents, aged approximately 11–14 years. Models couple a standard SABM for friendship network evolution with a proportional hazard model for first alcohol use. Meta-analysis of individual models for 12 schools found significant effects for friendship selection based on the same alco...
Pervasive Computing Location-aware Model Based on Ontology
Institute of Scientific and Technical Information of China (English)
PU Fang; CAI Hai-bin; CAO Qi-ying; SUN Dao-qing; LI Tong
2008-01-01
In order to integrate heterogeneous location-aware systems into pervasive computing environment, a novel pervasive computing location-aware model based on ontology is presented. A location-aware model ontology (LMO) is constructed. The location-aware model has the capabilities of sharing knowledge, reasoning and adjusting the usage policies of services dynamically through a unified semantic location manner. At last, the work process of our proposed location-aware model is explained by an application scenario.
A DNA based model for addition computation
Institute of Scientific and Technical Information of China (English)
GAO Lin; YANG Xiao; LIU Wenbin; XU Jin
2004-01-01
Much effort has been made to solve computing problems by using DNA-an organic simulating method, which in some cases is preferable to the current electronic computer. However, No one at present has proposed an effective and applicable method to solve addition problem with molecular algorithm due to the difficulty in solving the carry problem which can be easily solved by hardware of an electronic computer. In this article, we solved this problem by employing two kinds of DNA strings, one is called result and operation string while the other is named carrier. The result and operation string contains some carry information by its own and denotes the ultimate result while the carrier is just for carrying use. The significance of this algorithm is the original code, the fairly easy steps to follow and the feasibility under current molecular biological technology.
Computational intelligence applications in modeling and control
Vaidyanathan, Sundarapandian
2015-01-01
The development of computational intelligence (CI) systems was inspired by observable and imitable aspects of intelligent activity of human being and nature. The essence of the systems based on computational intelligence is to process and interpret data of various nature so that that CI is strictly connected with the increase of available data as well as capabilities of their processing, mutually supportive factors. Developed theories of computational intelligence were quickly applied in many fields of engineering, data analysis, forecasting, biomedicine and others. They are used in images and sounds processing and identifying, signals processing, multidimensional data visualization, steering of objects, analysis of lexicographic data, requesting systems in banking, diagnostic systems, expert systems and many other practical implementations. This book consists of 16 contributed chapters by subject experts who are specialized in the various topics addressed in this book. The special chapters have been brought ...
Benner, Aprile D.; Kim, Su Yeong
2010-01-01
In this brief report, we investigated whether the Family Stress Model could be replicated with a sample of Chinese American families. Path analyses with 444 adolescents and their parents provided support for the model's generalizability. Specifically, mothers' and fathers' reports of economic status (i.e., income, financial, and job instability)…
Longitudinal and Integrative Tests of Family Stress Model Effects on Mexican Origin Adolescents
White, Rebecca M. B.; Liu, Yu; Nair, Rajni L.; Tein, Jenn-Yun
2015-01-01
The family stress model represents a common framework through which to examine the effects of environmental stressors on adolescent adjustment. The model suggests that economic and neighborhood stressors influence youth adjustment via disruptions to parenting. Incorporating integrative developmental theory, we examined the degree to which parents'…
Seaton, Eleanor K.; Upton, Rachel; Gilbert, Adrianne; Volpe, Vanessa
2014-01-01
This study examined a moderated mediation model among 314 Black adolescents aged 13-18. The model included general coping strategies (e.g., active, distracting, avoidant, and support-seeking strategies) as mediators and racial identity dimensions (racial centrality, private regard, public regard, minority, assimilationist, and humanist ideologies)…
A Prospective Test of Cognitive Vulnerability Models of Depression with Adolescent Girls
Bohon, Cara; Stice, Eric; Burton, Emily; Fudell, Molly; Nolen-Hoeksema, Susan
2008-01-01
This study sought to provide a more rigorous prospective test of two cognitive vulnerability models of depression with longitudinal data from 496 adolescent girls. Results supported the cognitive vulnerability model in that stressors predicted future increases in depressive symptoms and onset of clinically significant major depression for…
Fox, Jeremy K.; Halpern, Leslie F.; Ryan, Julie L.; Lowe, Kelly A.
2010-01-01
Although the tripartite model reliably distinguishes anxiety and depression in adolescents, it remains unclear how negative affectivity (NA) and positive affectivity (PA) influence developmental pathways to internalizing problems. Based on models which propose that affectivity shapes how youth react to stress, the present study attempted to…
Adolescents and Music Media: Toward an Involvement-Mediational Model of Consumption and Self-Concept
Kistler, Michelle; Rodgers, Kathleen Boyce; Power, Thomas; Austin, Erica Weintraub; Hill, Laura Griner
2010-01-01
Using social cognitive theory and structural regression modeling, we examined pathways between early adolescents' music media consumption, involvement with music media, and 3 domains of self-concept (physical appearance, romantic appeal, and global self-worth; N=124). A mediational model was supported for 2 domains of self-concept. Music media…
King, Kevin M.; Molina, Brooke S. G.; Chassin, Laurie
2008-01-01
Stressful life events are an important risk factor for psychopathology among children and adolescents. However, variation in life stress may be both stable and time-varying with associated differences in the antecedents. We tested, using latent variable modeling, a state-trait model of stressful life events in adolescence, and predictors of…
Hutchinson, Delyse M.; Rapee, Ronald M.; Taylor, Alan
2010-01-01
This study tested five proposed models of the relationship of negative affect and peer factors in early adolescent body dissatisfaction, dieting, and bulimic behaviors. A large community sample of girls in early adolescence was assessed via questionnaire (X[overbar] age = 12.3 years). Structural equation modeling (SEM) indicated that negative…
A computational model of the human hand 93-ERI-053
Energy Technology Data Exchange (ETDEWEB)
Hollerbach, K.; Axelrod, T.
1996-03-01
The objectives of the Computational Hand Modeling project were to prove the feasibility of the Laboratory`s NIKE3D finite element code to orthopaedic problems. Because of the great complexity of anatomical structures and the nonlinearity of their behavior, we have focused on a subset of joints of the hand and lower extremity and have developed algorithms to model their behavior. The algorithms developed here solve fundamental problems in computational biomechanics and can be expanded to describe any other joints of the human body. This kind of computational modeling has never successfully been attempted before, due in part to a lack of biomaterials data and a lack of computational resources. With the computational resources available at the National Laboratories and the collaborative relationships we have established with experimental and other modeling laboratories, we have been in a position to pursue our innovative approach to biomechanical and orthopedic modeling.
Wang, Bo; Deveaux, Lynette; Lunn, Sonja; Dinaj-Koci, Veronica; Li, Xiaoming; Stanton, Bonita
2013-01-01
This study examined the relationships between youth and parental sensation-seeking, peer influence, parental monitoring and youth risk involvement in adolescence using structural equation modeling. Beginning in grade-six, longitudinal data were collected from 543 students over three years. Youth sensation-seeking in grade six contributed to risk involvement in early adolescence (grades six and seven) indirectly through increased peer risk influence and decreased parental monitoring but did no...
Mathematical modeling and computational intelligence in engineering applications
Silva Neto, Antônio José da; Silva, Geraldo Nunes
2016-01-01
This book brings together a rich selection of studies in mathematical modeling and computational intelligence, with application in several fields of engineering, like automation, biomedical, chemical, civil, electrical, electronic, geophysical and mechanical engineering, on a multidisciplinary approach. Authors from five countries and 16 different research centers contribute with their expertise in both the fundamentals and real problems applications based upon their strong background on modeling and computational intelligence. The reader will find a wide variety of applications, mathematical and computational tools and original results, all presented with rigorous mathematical procedures. This work is intended for use in graduate courses of engineering, applied mathematics and applied computation where tools as mathematical and computational modeling, numerical methods and computational intelligence are applied to the solution of real problems.
A Swarm Intelligence Based Model for Mobile Cloud Computing
Directory of Open Access Journals (Sweden)
Ahmed S. Salama
2015-01-01
Full Text Available Mobile Computing (MC provides multi services and a lot of advantages for millions of users across the world over the internet. Millions of business customers have leveraged cloud computing services through mobile devices to get what is called Mobile Cloud Computing (MCC. MCC aims at using cloud computing techniques for storage and processing of data on mobile devices, thereby reducing their limitations. This paper proposes architecture for a Swarm Intelligence Based Mobile Cloud Computing Model (SIBMCCM. A model that uses a proposed Parallel Particle Swarm Optimization (PPSO algorithm to enhance the access time for the mobile cloud computing services which support different E Commerce models and to better secure the communication through the mobile cloud and the mobile commerce transactions.
SmartShadow models and methods for pervasive computing
Wu, Zhaohui
2013-01-01
SmartShadow: Models and Methods for Pervasive Computing offers a new perspective on pervasive computing with SmartShadow, which is designed to model a user as a personality ""shadow"" and to model pervasive computing environments as user-centric dynamic virtual personal spaces. Just like human beings' shadows in the physical world, it follows people wherever they go, providing them with pervasive services. The model, methods, and software infrastructure for SmartShadow are presented and an application for smart cars is also introduced. The book can serve as a valuable reference work for resea
An integrated introduction to computer graphics and geometric modeling
Goldman, Ronald
2009-01-01
… this book may be the first book on geometric modelling that also covers computer graphics. In addition, it may be the first book on computer graphics that integrates a thorough introduction to 'freedom' curves and surfaces and to the mathematical foundations for computer graphics. … the book is well suited for an undergraduate course. … The entire book is very well presented and obviously written by a distinguished and creative researcher and educator. It certainly is a textbook I would recommend. …-Computer-Aided Design, 42, 2010… Many books concentrate on computer programming and soon beco
Computer modeling of ORNL storage tank sludge mobilization and mixing
International Nuclear Information System (INIS)
This report presents and analyzes the results of the computer modeling of mixing and mobilization of sludge in horizontal, cylindrical storage tanks using submerged liquid jets. The computer modeling uses the TEMPEST computational fluid dynamics computer program. The horizontal, cylindrical storage tank configuration is similar to the Melton Valley Storage Tanks (MVST) at Oak Ridge National (ORNL). The MVST tank contents exhibit non-homogeneous, non-Newtonian rheology characteristics. The eventual goals of the simulations are to determine under what conditions sludge mobilization using submerged liquid jets is feasible in tanks of this configuration, and to estimate mixing times required to approach homogeneity of the contents of the tanks
Macro—Dataflow Computational Model and Its Simulation
Institute of Scientific and Technical Information of China (English)
孙昱东; 谢志良
1990-01-01
This paper discusses the relationship between parallelism granularity and system overhead of dataflow computer systems,and indicates that a trade-off between them should be determined to obtain optimal efficiency of the overall system.On the basis of this discussion,a macro-dataflow computational model is established to exploit the task-level parallelism.Working as a macro-dataflow computer,an Experimental Distributed Dataflow Simulation System(EDDSS)is developed to examine the effectiveness of the macro-dataflow computational model.
Implementing and assessing computational modeling in introductory mechanics
Caballero, Marcos D.; Kohlmyer, Matthew A.; Schatz, Michael F.
2012-12-01
Students taking introductory physics are rarely exposed to computational modeling. In a one-semester large lecture introductory calculus-based mechanics course at Georgia Tech, students learned to solve physics problems using the VPython programming environment. During the term, 1357 students in this course solved a suite of 14 computational modeling homework questions delivered using an online commercial course management system. Their proficiency with computational modeling was evaluated with a proctored assignment involving a novel central force problem. The majority of students (60.4%) successfully completed the evaluation. Analysis of erroneous student-submitted programs indicated that a small set of student errors explained why most programs failed. We discuss the design and implementation of the computational modeling homework and evaluation, the results from the evaluation, and the implications for computational instruction in introductory science, technology, engineering, and mathematics (STEM) courses.
Counterconformity: an attribution model of adolescents' uniqueness-seeking behaviors in dressing.
Ling, I-Ling
2008-01-01
This article explores how an attribution model will illustrate uniqueness-seeking behavior in dressing in the Taiwanese adolescent subculture. The study employed 443 senior high school students. Results show that the tendency of uniqueness-seeking behavior in dressing is moderate. However, using cluster analysis to segment the counterconformity behavior of the subjects, the study demonstrates that there are two conspicuous types of segmentation "markets": rubber stamp and self-determined. The attribution models investigate the susceptibilities to informational and normative influence which have different direction impacts and weights on the adolescents' counterconformity behavior. More interestingly, path analyses indicate that consumer self-confidence mediates the relationship between informational influence and counterconformity behavior only on the rubber stamp type. This study then discusses how the adolescent consumers' need for uniqueness could be used in better understanding consumer behavior and the role consumption plays in their expression of identity. PMID:19149151
Models of parallel computation :a survey and classification
Institute of Scientific and Technical Information of China (English)
ZHANG Yunquan; CHEN Guoliang; SUN Guangzhong; MIAO Qiankun
2007-01-01
In this paper,the state-of-the-art parallel computational model research is reviewed.We will introduce various models that were developed during the past decades.According to their targeting architecture features,especially memory organization,we classify these parallel computational models into three generations.These models and their characteristics are discussed based on three generations classification.We believe that with the ever increasing speed gap between the CPU and memory systems,incorporating non-uniform memory hierarchy into computational models will become unavoidable.With the emergence of multi-core CPUs,the parallelism hierarchy of current computing platforms becomes more and more complicated.Describing this complicated parallelism hierarchy in future computational models becomes more and more important.A semi-automatic toolkit that can extract model parameters and their values on real computers can reduce the model analysis complexity,thus allowing more complicated models with more parameters to be adopted.Hierarchical memory and hierarchical parallelism will be two very important features that should be considered in future model design and research.
Fractal approach to computer-analytical modelling of tree crown
International Nuclear Information System (INIS)
In this paper we discuss three approaches to the modeling of a tree crown development. These approaches are experimental (i.e. regressive), theoretical (i.e. analytical) and simulation (i.e. computer) modeling. The common assumption of these is that a tree can be regarded as one of the fractal objects which is the collection of semi-similar objects and combines the properties of two- and three-dimensional bodies. We show that a fractal measure of crown can be used as the link between the mathematical models of crown growth and light propagation through canopy. The computer approach gives the possibility to visualize a crown development and to calibrate the model on experimental data. In the paper different stages of the above-mentioned approaches are described. The experimental data for spruce, the description of computer system for modeling and the variant of computer model are presented. (author). 9 refs, 4 figs
Integrating Numerical Computation into the Modeling Instruction Curriculum
Caballero, Marcos D; Aiken, John M; Douglas, Scott S; Scanlon, Erin M; Thoms, Brian; Schatz, Michael F
2012-01-01
We describe a way to introduce physics high school students with no background in programming to computational problem-solving experiences. Our approach builds on the great strides made by the Modeling Instruction reform curriculum. This approach emphasizes the practices of "Developing and using models" and "Computational thinking" highlighted by the NRC K-12 science standards framework. We taught 9th-grade students in a Modeling-Instruction-based physics course to construct computational models using the VPython programming environment. Numerical computation within the Modeling Instruction curriculum provides coherence among the curriculum's different force and motion models, links the various representations which the curriculum employs, and extends the curriculum to include real-world problems that are inaccessible to a purely analytic approach.
Computational modeling of induced emotion using GEMS
Aljanaki, Anna; Wiering, Frans; Veltkamp, Remco
2014-01-01
Most researchers in the automatic music emotion recognition field focus on the two-dimensional valence and arousal model. This model though does not account for the whole diversity of emotions expressible through music. Moreover, in many cases it might be important to model induced (felt) emotion, r
Conger, Rand D; Martin, Monica J; Masarik, April S; Widaman, Keith F; Donnellan, M Brent
2015-11-01
The present study examined the development of a cohort of 279 early adolescents (52% female) from 1990 to 2005. Guided by the interactionist model of socioeconomic status and human development, we proposed that parent aggressive personality, economic circumstances, interparental conflict, and parenting characteristics would affect the development of adolescent aggressive personality traits. In turn, we hypothesized that adolescent aggressiveness would have a negative influence on adolescent functioning as an adult in terms of economic success, personality development, and close relationships 11 years later. Findings were generally supportive of the interactionist model proposition that social and economic difficulties in the family of origin intensify risk for adolescent aggressive personality (the social causation hypothesis) and that this personality trait impairs successful transition to adult roles (the social selection hypothesis) in a transactional process over time and generations. These results underscore how early development leads to child influences that appear to directly hamper the successful transition to adult roles (statistical main effects) and also amplify the negative impact of dysfunctional family systems on the transition to adulthood (statistical interaction effects). The findings suggest several possible points of intervention that might help to disrupt this negative developmental sequence of events. PMID:26439065
Operation of the computer model for microenvironment atomic oxygen exposure
Bourassa, R. J.; Gillis, J. R.; Gruenbaum, P. E.
1995-01-01
A computer model for microenvironment atomic oxygen exposure has been developed to extend atomic oxygen modeling capability to include shadowing and reflections. The model uses average exposure conditions established by the direct exposure model and extends the application of these conditions to treat surfaces of arbitrary shape and orientation.
A non-additive negotiation model for utility computing markets
Macías Lloret, Mario; Guitart Fernández, Jordi
2009-01-01
Market-based resource allocation is a promising model for dealing with the growing Utility Computing environments, such as Grid or Cloud Computing. Agents that represent both service clients and providers meet in a market to negotiate the terms of the sale of resources. Additive negotiation models are extended because they are simple, but they are not valid for negotiations whose terms are not independent between them. This paper proposes a simple non-additive model for performing negotiat...
Classical model for bulk-ensemble NMR quantum computation
Schack, R.; Caves, C. M.
1999-01-01
We present a classical model for bulk-ensemble NMR quantum computation: the quantum state of the NMR sample is described by a probability distribution over the orientations of classical tops, and quantum gates are described by classical transition probabilities. All NMR quantum computing experiments performed so far with three quantum bits can be accounted for in this classical model. After a few entangling gates, the classical model suffers an exponential decrease of the measured signal, whe...
Introduction to computation and modeling for differential equations
Edsberg, Lennart
2008-01-01
An introduction to scientific computing for differential equationsIntroduction to Computation and Modeling for Differential Equations provides a unified and integrated view of numerical analysis, mathematical modeling in applications, and programming to solve differential equations, which is essential in problem-solving across many disciplines, such as engineering, physics, and economics. This book successfully introduces readers to the subject through a unique ""Five-M"" approach: Modeling, Mathematics, Methods, MATLAB, and Multiphysics. This approach facilitates a thorough understanding of h
Computer-based modelling and analysis in engineering geology
Giles, David
2014-01-01
This body of work presents the research and publications undertaken under a general theme of computer-based modelling and analysis in engineering geology. Papers are presented on geotechnical data management, data interchange, Geographical Information Systems, surface modelling, geostatistical methods, risk-based modelling, knowledge-based systems, remote sensing in engineering geology and on the integration of computer applications into applied geoscience teaching. The work highlights my...
Computer vision techniques for background modelling in urban traffic monitoring
Milla, José Manuel; S. L. Toral; Vargas Villanueva, Manuel; Barrero, Federico; Soylu, Seref
2010-01-01
Jose Manuel Milla, Sergio Luis Toral, Manuel Vargas and Federico Barrero (2010). Computer Vision Techniques for Background Modeling in Urban Traffic Monitoring, Urban Transport and Hybrid Vehicles, Seref Soylu (Ed.), ISBN: 978-953-307-100-8, InTech, DOI: 10.5772/10179. Available from: http://www.intechopen.com/books/urban-transport-and-hybrid-vehicles/computer-vision-techniques-for-background-modeling-in-urban-traffic-monitoring In this chapter, several background modelling techniques have...
Computational neurorehabilitation: modeling plasticity and learning to predict recovery.
Reinkensmeyer, David J; Burdet, Etienne; Casadio, Maura; Krakauer, John W; Kwakkel, Gert; Lang, Catherine E; Swinnen, Stephan P; Ward, Nick S; Schweighofer, Nicolas
2016-01-01
Despite progress in using computational approaches to inform medicine and neuroscience in the last 30 years, there have been few attempts to model the mechanisms underlying sensorimotor rehabilitation. We argue that a fundamental understanding of neurologic recovery, and as a result accurate predictions at the individual level, will be facilitated by developing computational models of the salient neural processes, including plasticity and learning systems of the brain, and integrating them into a context specific to rehabilitation. Here, we therefore discuss Computational Neurorehabilitation, a newly emerging field aimed at modeling plasticity and motor learning to understand and improve movement recovery of individuals with neurologic impairment. We first explain how the emergence of robotics and wearable sensors for rehabilitation is providing data that make development and testing of such models increasingly feasible. We then review key aspects of plasticity and motor learning that such models will incorporate. We proceed by discussing how computational neurorehabilitation models relate to the current benchmark in rehabilitation modeling - regression-based, prognostic modeling. We then critically discuss the first computational neurorehabilitation models, which have primarily focused on modeling rehabilitation of the upper extremity after stroke, and show how even simple models have produced novel ideas for future investigation. Finally, we conclude with key directions for future research, anticipating that soon we will see the emergence of mechanistic models of motor recovery that are informed by clinical imaging results and driven by the actual movement content of rehabilitation therapy as well as wearable sensor-based records of daily activity.
Directory of Open Access Journals (Sweden)
Mobley Connie
2011-05-01
Full Text Available Abstract Background The objective of this study was to measure the validity and reliability of a multifactorial Risk Factor Model developed for use in predicting future caries risk in Nevada adolescents in a public health setting. Methods This study examined retrospective data from an oral health surveillance initiative that screened over 51,000 students 13-18 years of age, attending public/private schools in Nevada across six academic years (2002/2003-2007/2008. The Risk Factor Model included ten demographic variables: exposure to fluoridation in the municipal water supply, environmental smoke exposure, race, age, locale (metropolitan vs. rural, tobacco use, Body Mass Index, insurance status, sex, and sealant application. Multiple regression was used in a previous study to establish which significantly contributed to caries risk. Follow-up logistic regression ascertained the weight of contribution and odds ratios of the ten variables. Researchers in this study computed sensitivity, specificity, positive predictive value (PVP, negative predictive value (PVN, and prevalence across all six years of screening to assess the validity of the Risk Factor Model. Results Subjects' overall mean caries prevalence across all six years was 66%. Average sensitivity across all six years was 79%; average specificity was 81%; average PVP was 89% and average PVN was 67%. Conclusions Overall, the Risk Factor Model provided a relatively constant, valid measure of caries that could be used in conjunction with a comprehensive risk assessment in population-based screenings by school nurses/nurse practitioners, health educators, and physicians to guide them in assessing potential future caries risk for use in prevention and referral practices.
The Validation of Computer-based Models in Engineering: Some Lessons from Computing Science
Directory of Open Access Journals (Sweden)
D. J. Murray-Smith
2001-01-01
Full Text Available Questions of the quality of computer-based models and the formal processes of model testing, involving internal verification and external validation, are usually given only passing attention in engineering reports and in technical publications. However, such models frequently provide a basis for analysis methods, design calculations or real-time decision-making in complex engineering systems. This paper reviews techniques used for external validation of computer-based models and contrasts the somewhat casual approach which is usually adopted in this field with the more formal approaches to software testing and documentation recommended for large software projects. Both activities require intimate knowledge of the intended application, a systematic approach and considerable expertise and ingenuity in the design of tests. It is concluded that engineering degree courses dealing with modelling techniques and computer simulation should put more emphasis on model limitations, testing and validation.
Performance Predictable ServiceBSP Model for Grid Computing
Institute of Scientific and Technical Information of China (English)
TONG Weiqin; MIAO Weikai
2007-01-01
This paper proposes a performance prediction model for grid computing model ServiceBSP to support developing high quality applications in grid environment. In ServiceBSP model,the agents carrying computing tasks are dispatched to the local domain of the selected computation services. By using the IP (integer program) approach, the Service Selection Agent selects the computation services with global optimized QoS (quality of service) consideration. The performance of a ServiceBSP application can be predicted according to the performance prediction model based on the QoS of the selected services. The performance prediction model can help users to analyze their applications and improve them by optimized the factors which affects the performance. The experiment shows that the Service Selection Agent can provide ServiceBSP users with satisfied QoS of applications.
Robust speech features representation based on computational auditory model
Institute of Scientific and Technical Information of China (English)
LU Xugang; JIA Chuan; DANG Jianwu
2004-01-01
A speech signal processing and features extracting method based on computational auditory model is proposed. The computational model is based on psychological, physiological knowledge and digital signal processing methods. In each stage of a hearing perception system, there is a corresponding computational model to simulate its function. Based on this model, speech features are extracted. In each stage, the features in different kinds of level are extracted. A further processing for primary auditory spectrum based on lateral inhibition is proposed to extract much more robust speech features. All these features can be regarded as the internal representations of speech stimulation in hearing system. The robust speech recognition experiments are conducted to test the robustness of the features. Results show that the representations based on the proposed computational auditory model are robust representations for speech signals.
The Architectural Designs of a Nanoscale Computing Model
Directory of Open Access Journals (Sweden)
Mary M. Eshaghian-Wilner
2004-08-01
Full Text Available A generic nanoscale computing model is presented in this paper. The model consists of a collection of fully interconnected nanoscale computing modules, where each module is a cube of cells made out of quantum dots, spins, or molecules. The cells dynamically switch between two states by quantum interactions among their neighbors in all three dimensions. This paper includes a brief introduction to the field of nanotechnology from a computing point of view and presents a set of preliminary architectural designs for fabricating the nanoscale model studied.
Computational modeling of shallow geothermal systems
Al-Khoury, Rafid
2011-01-01
A Step-by-step Guide to Developing Innovative Computational Tools for Shallow Geothermal Systems Geothermal heat is a viable source of energy and its environmental impact in terms of CO2 emissions is significantly lower than conventional fossil fuels. Shallow geothermal systems are increasingly utilized for heating and cooling of buildings and greenhouses. However, their utilization is inconsistent with the enormous amount of energy available underneath the surface of the earth. Projects of this nature are not getting the public support they deserve because of the uncertainties associated with
Transforming High School Physics with Modeling and Computation
Aiken, John M
2013-01-01
The Engage to Excel (PCAST) report, the National Research Council's Framework for K-12 Science Education, and the Next Generation Science Standards all call for transforming the physics classroom into an environment that teaches students real scientific practices. This work describes the early stages of one such attempt to transform a high school physics classroom. Specifically, a series of model-building and computational modeling exercises were piloted in a ninth grade Physics First classroom. Student use of computation was assessed using a proctored programming assignment, where the students produced and discussed a computational model of a baseball in motion via a high-level programming environment (VPython). Student views on computation and its link to mechanics was assessed with a written essay and a series of think-aloud interviews. This pilot study shows computation's ability for connecting scientific practice to the high school science classroom.
[Model of Engagement and Dropout for Adolescents with Borderline Personality Disorder].
Desrosiers, Lyne; Saint-Jean, Micheline; Laporte, Lise
2016-01-01
treatment were formalized in the Model of engagement and treatment dropout for adolescent with BPD. This theoretical model highlights two key milestones that may lead to treatment completion or to dropout during care. It illustrates that distinct processes characterize the premature and late dropouts of adolescents with BPD. The early terminations result from the failure of the care-setting to take advantage of the impetus for help seeking to engage the adolescent and the parent at that first critical moment in the care trajectory. On the other hand, the late dropouts translate failures of the care-setting to adopt corrective measures to maintain the patient in treatment at a second critical moment indicated by their disengagement.Conclusion The termination rate of those adolescent treatments could be diminished by a system of care-setting that recognizes the inherent difficulties related to the treatment of those specific patients, is proactive to solve problems of disengagement, integrates support systems for clinicians and promotes a reflexive practice. PMID:27570961
Computational Modeling of Turbulent Spray Combustion
Ma, L.
2016-01-01
The objective of the research presented in this thesis is development and validation of predictive models or modeling approaches of liquid fuel combustion (spray combustion) in hot-diluted environments, known as flameless combustion or MILD combustion. The goal is to combine good physical insight, a
Computing broadband accelerograms using kinematic rupture modeling
International Nuclear Information System (INIS)
In order to make the broadband kinematic rupture modeling more realistic with respect to dynamic modeling, physical constraints are added to the rupture parameters. To improve the slip velocity function (SVF) modeling, an evolution of the k-2 source model is proposed, which consists to decompose the slip as a sum of sub-events by band of k. This model yields to SVF close to the solution proposed by Kostrov for a crack, while preserving the spectral characteristics of the radiated wave field, i.e. a w2 model with spectral amplitudes at high frequency scaled to the coefficient of directivity Cd. To better control the directivity effects, a composite source description is combined with a scaling law defining the extent of the nucleation area for each sub-event. The resulting model allows to reduce the apparent coefficient of directivity to a fraction of Cd, as well as to reproduce the standard deviation of the new empirical attenuation relationships proposed for Japan. To make source models more realistic, a variable rupture velocity in agreement with the physics of the rupture must be considered. The followed approach that is based on an analytical relation between the fracture energy, the slip and the rupture velocity, leads to higher values of the peak ground acceleration in the vicinity of the fault. Finally, to better account for the interaction of the wave field with the geological medium, a semi-empirical methodology is developed combining a composite source model with empirical Green functions, and is applied to the Yamaguchi, Mw 5.9 earthquake. The modeled synthetics reproduce satisfactorily well the observed main characteristics of ground motions. (author)
Garmy, Pernilla; Clausson, Eva K; Nyberg, Per; Jakobsson, Ulf
2014-06-01
The aim of this cross-sectional study was to investigate the prevalence of overweight and obesity in children and adolescents (6-16 years), and relationships between being overweight and sleep, experiencing of fatigue, enjoyment of school, and time spent in watching television and in sitting at the computer. Trained school nurses measured the weight and height of 2891 children aged 6, 7, 10, 14, and 16, and distributed a questionnaire to them regarding television and computer habits, sleep, and enjoyment of school. Overweight, obesity included, was present in 16.1% of the study population. Relationships between lifestyle factors and overweight were studied using multivariate logistic regression analysis. Having a bedroom television and spending more than 2 h a day watching television were found to be associated with overweight (OR 1.26 and 1.55 respectively). No association was found between overweight and time spent at the computer, short sleep duration, enjoyment of school, tiredness at school, or difficulties in sleeping and waking up. It is recommended that the school health service discuss with pupils their media habits so as to promote their maintaining a healthy lifestyle. PMID:23796145
Thøgersen-Ntoumani, Cecilie; Ntoumanis, Nikos
2010-01-01
This study used self-determination theory (Deci, E.L., & Ryan, R.M. (2000). The 'what' and 'why' of goal pursuits: Human needs and the self-determination of behavior. Psychological Inquiry, 11, 227-268.) to examine predictors of body image concerns and unhealthy weight control behaviours in a sample of 350 Greek adolescent girls. A process model was tested which proposed that perceptions of parental autonomy support and two life goals (health and image) would predict adolescents' degree of sa...
Modeling of Longitudinal Changes in Left Ventricular Dimensions among Female Adolescent Runners
Norimitsu Kinoshita; Fuminori Katsukawa; Hajime Yamazaki
2015-01-01
Purpose Left ventricular (LV) enlargement has been linked to sudden cardiac death among young athletes. This study aimed to model the effect of long-term incessant endurance training on LV dimensions in female adolescent runners. Methods Japanese female adolescent competitive distance runners (n = 36, age: 15 years, height: 158.1 ± 4.6 cm, weight: 44.7 ± 6.1 kg, percent body fat: 17.0 ± 5.2%) underwent echocardiography and underwater weighing every 6 months for 3 years. Since the measurement ...
Chen, Ang; Hancock, Gregory R.
2006-01-01
Adolescent physical inactivity has risen to an alarming rate. Several theoretical frameworks (models) have been proposed and tested in school-based interventions. The results are mixed, indicating a similar weakness as that observed in community-based physical activity interventions (Baranowski, Lin, Wetter, Resnicow, & Hearn, 1997). The…
Hagger, Martin S.; Biddle, Stuart J. H.; John Wang, C. K.
2005-01-01
This study tests the generalizability of the factor pattern, structural parameters, and latent mean structure of a multidimensional, hierarchical model of physical self-concept in adolescents across gender and grade. A children's version of the Physical Self-Perception Profile (C-PSPP) was administered to seventh-, eighth- and ninth-grade high…
P.M. Valkenburg; J. Peter
2011-01-01
Adolescents far outnumber adults in their use of e-communication technologies, such as instant messaging and social network sites. In this article, we present an integrative model that helps us to understand both the appeal of these technologies and their risks and opportunities for the psychosocial
Testing Structural Models of DSM-IV Symptoms of Common Forms of Child and Adolescent Psychopathology
Lahey, Benjamin B.; Rathouz, Paul J.; Van Hulle, Carol; Urbano, Richard C.; Krueger, Robert F.; Applegate, Brooks; Garriock, Holly A.; Chapman, Derek A.; Waldman, Irwin D.
2008-01-01
Confirmatory factor analyses were conducted of "Diagnostic and Statistical Manual of Mental Disorders", Fourth Edition (DSM-IV) symptoms of common mental disorders derived from structured interviews of a representative sample of 4,049 twin children and adolescents and their adult caretakers. A dimensional model based on the assignment of symptoms…
Facebook and the Cognitive Model: A Tool for Promoting Adolescent Self-Awareness
Lewis, Lucy; Wahesh, Edward
2012-01-01
A homework activity incorporating the social networking site Facebook is presented as a tool for teaching adolescent clients about the cognitive model and increasing their ability to identify and modify problematic thinking. The authors describe how a worksheet developed to help clients examine information presented on their Facebook profile can…
Depression amongst Chinese Adolescents in Hong Kong: An Evaluation of a Stress Moderation Model
Ng, Catalina S. M.; Hurry, Jane
2011-01-01
Stress has an established association with depression. However, not all adolescents experiencing stressors become depressed and it is helpful to identify potential resilience factors. The current study tests a theoretical extension of a stress-diathesis model of depression in a Chinese context, with stress, coping, family relationships, and…
Mental Health, School Problems, and Social Networks: Modeling Urban Adolescent Substance Use
Mason, Michael J.
2010-01-01
This study tested a mediation model of the relationship with school problems, social network quality, and substance use with a primary care sample of 301 urban adolescents. It was theorized that social network quality (level of risk or protection in network) would mediate the effects of school problems, accounting for internalizing problems and…
A Social Operational Model of Urban Adolescents' Tobacco and Substance Use: A Mediational Analysis
Mason, Michael J.; Mennis, Jeremy; Schmidt, Christopher D.
2011-01-01
This study tested a mediation model of the relationship with tobacco use, social network quality (level of risk or protection in a network), and substance use (alcohol and/or illicit drugs) with a sample of 301 urban adolescents. It was theorized that social network quality would mediate the effect of tobacco use, accounting for PTSD symptoms and…
Towards a Model of Suicidal Ideation for Hong Kong Chinese Adolescents
Sun, Rachel C. F.; Hui, Eadaoin K. P.; Watkins, David
2006-01-01
This study tested a model of suicidal ideation with family cohesion, expressiveness, conflicts, teacher support, teacher-student relationships and peer support as antecedents, and self-esteem and depression as mediators. Data was collected from survey questionnaires with 433 Hong Kong Chinese adolescents. The results showed that only family…
Williams, Tricia S.; Connolly, Jennifer; Pepler, Debra; Craig, Wendy; Laporte, Lise
2008-01-01
The present study examined physical dating aggression in different adolescent relationships and assessed linear, threshold, and moderator risk models for recurrent aggressive relationships. The 621 participants (59% girls, 41% boys) were drawn from a 1-year longitudinal survey of Canadian high school youths ranging from Grade 9 through Grade 12.…
Davies, Emma; Martin, Jilly; Foxcroft, David
2016-01-01
Purpose: The purpose of this paper is to report on the use of the Delphi method to gain expert feedback on the identification of behaviour change techniques (BCTs) and development of a novel intervention to reduce adolescent alcohol misuse, based on the Prototype Willingness Model (PWM) of health risk behaviour. Design/methodology/approach: Four…
The Metacognitive Model of Generalized Anxiety Disorder in Children and Adolescents
Ellis, Danielle M.; Hudson, Jennifer L.
2010-01-01
Worry is a common phenomenon in children and adolescents, with some experiencing excessive worries that cause significant distress and interference. The metacognitive model of generalized anxiety disorder (Wells 1995, 2009) was developed to explain cognitive processes associated with pathological worry in adults, particularly the role of positive…
Testing an Idealized Dynamic Cascade Model of the Development of Serious Violence in Adolescence
Dodge, Kenneth A.; Greenberg, Mark T.; Malone, Patrick S.
2008-01-01
A dynamic cascade model of development of serious adolescent violence was proposed and tested through prospective inquiry with 754 children (50% male; 43% African American) from 27 schools at 4 geographic sites followed annually from kindergarten through Grade 11 (ages 5-18). Self, parent, teacher, peer, observer, and administrative reports…
Testing a Model of Resistance to Peer Pressure among Mexican-Origin Adolescents
Bamaca, Mayra Y.; Umana-Taylor, Adriana J.
2006-01-01
This study examined the factors associated with resistance to peer pressure toward antisocial behaviors among a sample of Mexican-origin adolescents (n=564) living in a large Southwestern city in the U.S. A model examining the influence of generational status, emotional autonomy from parents, and self-esteem on resistance to peer pressure was…
A computational model of cardiovascular physiology and heart sound generation.
Watrous, Raymond L
2009-01-01
A computational model of the cardiovascular system is described which provides a framework for implementing and testing quantitative physiological models of heart sound generation. The lumped-parameter cardiovascular model can be solved for the hemodynamic variables on which the heart sound generation process is built. Parameters of the cardiovascular model can be adjusted to represent various normal and pathological conditions, and the acoustic consequences of those adjustments can be explored. The combined model of the physiology of cardiovascular circulation and heart sound generation has promise for application in teaching, training and algorithm development in computer-aided auscultation of the heart.
Computational model of cellular metabolic dynamics
DEFF Research Database (Denmark)
Li, Yanjun; Solomon, Thomas; Haus, Jacob M;
2010-01-01
Identifying the mechanisms by which insulin regulates glucose metabolism in skeletal muscle is critical to understanding the etiology of insulin resistance and type 2 diabetes. Our knowledge of these mechanisms is limited by the difficulty of obtaining in vivo intracellular data. To quantitatively...... cytosol and mitochondria. The model simulated skeletal muscle metabolic responses to insulin corresponding to human hyperinsulinemic-euglycemic clamp studies. Insulin-mediated rate of glucose disposal was the primary model input. For model validation, simulations were compared with experimental data...... type 2 diabetes....
Mental Health, School Problems, and Social Networks: Modeling Urban Adolescent Substance Use
Mason, Michael J.
2010-01-01
This study tested a mediation model of the relationship with school problems, social network quality, and substance use with a primary care sample of 301 urban adolescents. It was theorized that social network quality (level of risk or protection in network) would mediate the effects of school problems, accounting for internalizing problems and relations with parents, on substance use. Results of path modeling with AMOS showed that the model provided a very good fit to the data and demonstrat...
Chen, Lung Hung; Kee, Ying Hwa; Tsai, Ying-Mei
2009-01-01
The dual model of perfectionism (Slade and Owens, Behav Modificat 22(3):372-390, 1998) is adopted to examine the influence of adaptive and maladaptive perfectionism on adolescent athlete burnout in Taiwan. Participants were 188 high school adolescent student-athletes (M = 16.48, SD = 0.59). They were administered the Multidimensional Inventory of…
Doornwaard, Suzan M.; Ter Bogt, Tom F M; Reitz, Ellen; Van Den Eijnden, Regina J J M
2015-01-01
Research on the role of sex-related Internet use in adolescents' sexual development has often isolated the Internet and online behaviors from other, offline influencing factors in adolescents' lives, such as processes in the peer domain. The aim of this study was to test an integrative model explain
Donati, Maria Anna; Chiesi, Francesca; Primi, Caterina
2013-01-01
This study aimed at testing a model in which cognitive, dispositional, and social factors were integrated into a single perspective as predictors of gambling behavior. We also aimed at providing further evidence of gender differences related to adolescent gambling. Participants were 994 Italian adolescents (64% Males; Mean age = 16.57).…
Hero/heroine modeling for Puerto Rican adolescents: a preventive mental health intervention.
Malgady, R G; Rogler, L H; Costantino, G
1990-08-01
Culturally sensitive treatments of the special mental health needs of high-risk Puerto Rican adolescents are lacking. The hero/heroine intervention was based on adult Puerto Rican role models to foster ethnic identity, self-concept, and adaptive coping behavior. 90 nonclinical Puerto Rican 8th and 9th graders were screened for presenting behavior problems in school and randomly assigned to an intervention and a control group. After 19 sessions, the intervention significantly increased adolescents' ethnic identity and self-concept and reduced anxiety. Treatment outcomes varied as a function of grade level, sex, and household composition. Self-concept was negatively affected among girls from intact families. The study supports the effectiveness of the culturally sensitive modality as a preventive mental health intervention for high-risk Puerto Rican adolescents, especially from single-parent families.
Transport modeling and advanced computer techniques
International Nuclear Information System (INIS)
A workshop was held at the University of Texas in June 1988 to consider the current state of transport codes and whether improved user interfaces would make the codes more usable and accessible to the fusion community. Also considered was the possibility that a software standard could be devised to ease the exchange of routines between groups. It was noted that two of the major obstacles to exchanging routines now are the variety of geometrical representation and choices of units. While the workshop formulated no standards, it was generally agreed that good software engineering would aid in the exchange of routines, and that a continued exchange of ideas between groups would be worthwhile. It seems that before we begin to discuss software standards we should review the current state of computer technology --- both hardware and software to see what influence recent advances might have on our software goals. This is done in this paper
Computational numerical modelling of plasma focus
International Nuclear Information System (INIS)
Several models for calculation of the dynamics of Plasma Focus have been developed. All of them begin from the same physic principle: the current sheet run down the anode length, ionizing and collecting the gas that finds in its way.This is known as snow-plow model.Concerning pinch's compression, a MHD model is proposed.The plasma is treated as a fluid , particularly as a high ionized gas.However, there are not many models that, taking into account thermal equilibrium inside the plasma, make approximated calculations of the maximum temperatures reached in the pinch.Besides, there are no models which use those temperatures to estimate the termofusion neutron yield for the Deuterium or Deuterium-Tritium gas filled cases.In the PLADEMA network (Dense Magnetized Plasmas) a code was developed with the objective of describe the plasma focus dynamics, in a conceptual engineering stage.The codes calculates the principal variables (currents, time to focus, etc) and estimates the neutron yield in Deuterium-filled plasma focus devices.It can be affirmed that the code's experimental validation, in its axial and radial stages, was very successfully. However, it was accepted that the compression stage should be formulated again, to find a solution for a large variation of a parameter related with velocity profiles for the particles trapped inside the pinch.The objectives of this work can be stated in the next way : - Check the compression's model hypothesis. Develop a new model .- Implement the new model in the code. Compare results against experimental data of Plasma Focus devices from all around the world
Computational Modeling of Healthy Myocardium in Diastole.
Nikou, Amir; Dorsey, Shauna M; McGarvey, Jeremy R; Gorman, Joseph H; Burdick, Jason A; Pilla, James J; Gorman, Robert C; Wenk, Jonathan F
2016-04-01
In order to better understand the mechanics of the heart and its disorders, engineers increasingly make use of the finite element method (FEM) to investigate healthy and diseased cardiac tissue. However, FEM is only as good as the underlying constitutive model, which remains a major challenge to the biomechanics community. In this study, a recently developed structurally based constitutive model was implemented to model healthy left ventricular myocardium during passive diastolic filling. This model takes into account the orthotropic response of the heart under loading. In-vivo strains were measured from magnetic resonance images (MRI) of porcine hearts, along with synchronous catheterization pressure data, and used for parameter identification of the passive constitutive model. Optimization was performed by minimizing the difference between MRI measured and FE predicted strains and cavity volumes. A similar approach was followed for the parameter identification of a widely used phenomenological constitutive law, which is based on a transversely isotropic material response. Results indicate that the parameter identification with the structurally based constitutive law is more sensitive to the assigned fiber architecture and the fit between the measured and predicted strains is improved with more realistic sheet angles. In addition, the structurally based model is capable of generating a more physiological end-diastolic pressure-volume relationship in the ventricle. PMID:26215308
Recent Applications of Hidden Markov Models in Computational Biology
Institute of Scientific and Technical Information of China (English)
Khar Heng Choo; Joo Chuan Tong; Louxin Zhang
2004-01-01
This paper examines recent developments and applications of Hidden Markov Models (HMMs) to various problems in computational biology, including multiple sequence alignment, homology detection, protein sequences classification, and genomic annotation.
Computational Modeling, Formal Analysis, and Tools for Systems Biology.
Directory of Open Access Journals (Sweden)
Ezio Bartocci
2016-01-01
Full Text Available As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verification. Here, we discuss the most important and exciting computational methods and tools currently available to systems biologists. We believe that a deeper understanding of the concepts and theory highlighted in this review will produce better software practice, improved investigation of complex biological processes, and even new ideas and better feedback into computer science.
The Next Generation ARC Middleware and ATLAS Computing Model
Filipcic, A; The ATLAS collaboration; Smirnova, O; Konstantinov, A; Karpenko, D
2012-01-01
The distributed NDGF Tier-1 and associated Nordugrid clusters are well integrated into the ATLAS computing model but follow a slightly different paradigm than other ATLAS resources. The current strategy does not divide the sites as in the commonly used hierarchical model, but rather treats them as a single storage endpoint and a pool of distributed computing nodes. The next generation ARC middleware with its several new technologies provides new possibilities in development of the ATLAS computing model, such as pilot jobs with pre-cached input files, automatic job migration between the sites, integration of remote sites without connected storage elements, and automatic brokering for jobs with non-standard resource requirements. ARC's data transfer model provides an automatic way for the computing sites to participate in ATLAS' global task management system without requiring centralised brokering or data transfer services. The powerful API combined with Python and Java bindings can easily be used to build new ...
Hybrid Computational Model for High-Altitude Aeroassist Vehicles Project
National Aeronautics and Space Administration — A hybrid continuum/noncontinuum computational model will be developed for analyzing the aerodynamics and heating on aeroassist vehicles. Unique features of this...
Hybrid Computational Model for High-Altitude Aeroassist Vehicles Project
National Aeronautics and Space Administration — The proposed effort addresses a need for accurate computational models to support aeroassist and entry vehicle system design over a broad range of flight conditions...
ON GLOBAL STABILITY OF A NONRESIDENT COMPUTER VIRUS MODEL
Institute of Scientific and Technical Information of China (English)
Yoshiaki MUROYA; Huaixing LI; Toshikazu KUNIYA
2014-01-01
In this paper, we establish new sufficient conditions for the infected equilibrium of a nonresident computer virus model to be globally asymptotically stable. Our results extend two kind of known results in recent literature.
Computational Modeling, Formal Analysis, and Tools for Systems Biology.
Bartocci, Ezio; Lió, Pietro
2016-01-01
As the amount of biological data in the public domain grows, so does the range of modeling and analysis techniques employed in systems biology. In recent years, a number of theoretical computer science developments have enabled modeling methodology to keep pace. The growing interest in systems biology in executable models and their analysis has necessitated the borrowing of terms and methods from computer science, such as formal analysis, model checking, static analysis, and runtime verification. Here, we discuss the most important and exciting computational methods and tools currently available to systems biologists. We believe that a deeper understanding of the concepts and theory highlighted in this review will produce better software practice, improved investigation of complex biological processes, and even new ideas and better feedback into computer science.
Zemel, Babette; Bass, Shona; Binkley, Teresa; Ducher, Gaele; Macdonald, Heather; McKay, Heather; Moyer-Mileur, Laurie; Shepherd, John; Specker, Bonny; Ward, Kate; Hans, Didier
2008-01-01
Peripheral quantitative computed tomography (pQCT) has mainly been used as a research tool in children. To evaluate the clinical utility of pQCT and formulate recommendations for its use in children, the International Society of Clinical Densitometry (ISCD) convened a task force to review the literature and propose areas of consensus and future research. The types of pQCT technology available, the clinical application of pQCT for bone health assessment in children, the important elements to be included in a pQCT report, and quality control monitoring techniques were evaluated. The review revealed a lack of standardization of pQCT techniques, and a paucity of data regarding differences between pQCT manufacturers, models and software versions and their impact in pediatric assessment. Measurement sites varied across studies. Adequate reference data, a critical element for interpretation of pQCT results, were entirely lacking, although some comparative data on healthy children were available. The elements of the pQCT clinical report and quality control procedures are similar to those recommended for dual-energy X-ray absorptiometry. Future research is needed to establish evidence-based criteria for the selection of the measurement site, scan acquisition and analysis parameters, and outcome measures. Reference data that sufficiently characterize the normal range of variability in the population also need to be established.
Multiscale Computing with the Multiscale Modeling Library and Runtime Environment
Borgdorff J.; Mamonski M.; Bosak B.; Groen D.; Ben Belgacem M.; Kurowski K.; Hoekstra A.G.
2013-01-01
We introduce a software tool to simulate multiscale models: The Multiscale Coupling Library and Environment 2 (MUSCLE 2). MUSCLE 2 is a component-based modeling tool inspired by the multiscale modeling and simulation framework, with an easy-to-use API which supports Java, C++, C, and Fortran. We present MUSCLE 2's runtime features, such as its distributed computing capabilities, and its benefits to multiscale modelers. We also describe two multiscale models that use MUSCLE 2 to do distributed...
Theoretic computing model of combustion process of asphalt smoke
Institute of Scientific and Technical Information of China (English)
HUANG Rui; CHAI Li-yuan; HE De-wen; PENG Bing; WANG Yun-yan
2005-01-01
Based on the data and methods provided by research literature, dispersing mathematical model of combustion process of asphalt smoke is set by theoretic analysis. Through computer programming, the dynamic combustion process of asphalt smoke is calculated to simulate an experimental model. The computing result shows that the temperature and the concentration of asphalt smoke influence its burning temperature in approximatively linear manner. The consumed quantity of fuel to ignite the asphalt smoke needs to be measured from the two factors.
A Situative Space Model for Mobile Mixed-Reality Computing
DEFF Research Database (Denmark)
Pederson, Thomas; Janlert, Lars-Erik; Surie, Dipak
2011-01-01
This article proposes a situative space model that links the physical and virtual realms and sets the stage for complex human-computer interaction defined by what a human agent can see, hear, and touch, at any given point in time.......This article proposes a situative space model that links the physical and virtual realms and sets the stage for complex human-computer interaction defined by what a human agent can see, hear, and touch, at any given point in time....
Cascade recursion models of computing the temperatures of underground layers
Institute of Scientific and Technical Information of China (English)
HAN Liqun; BI Siwen; SONG Shixin
2006-01-01
An RBF neural network was used to construct computational models of the underground temperatures of different layers, using ground-surface parameters and the temperatures of various underground layers. Because series recursion models also enable researchers to use above-ground surface parameters to compute the temperatures of different underground layers, this method provides a new way of using thermal infrared remote sensing to monitor the suture zones of large areas of blocks and to research thermal anomalies in geologic structures.
Computing Small 1-Homological Models for Commutative Differential Graded Algebras
Alvarez, Victor; Armario, Jose Andres; Frau, Maria Dolores; Gonzalez-Diaz, Rocio; Jimenez, Maria Jose; Real, Pedro; Silva, Beatriz
2001-01-01
We use homological perturbation machinery specific for the algebra category [P. Real. Homological Perturbation Theory and Associativity. Homology, Homotopy and Applications vol. 2, n. 5 (2000) 51-88] to give an algorithm for computing the differential structure of a small 1--homological model for commutative differential graded algebras (briefly, CDGAs). The complexity of the procedure is studied and a computer package in Mathematica is described for determining such models.
Computational modelling, explicit mathematical treatments, and scientific explanation
Bryden, J; Noble, J
2006-01-01
A computer simulation model, can produce some interesting and surprising results which one would not expect from initial analysis of the algorithm and data. We question however, whether the description of such a computer simulation modelling procedure (data + algorithm + results) can constitute an explanation as to why the algorithm produces such an effect. Specifically, in the field of theoretical biology, can such a procedure constitute real scientific explanation of biological phenomena? W...
Computational model of miniature pulsating heat pipes.
Energy Technology Data Exchange (ETDEWEB)
Martinez, Mario J.; Givler, Richard C.
2013-01-01
The modeling work described herein represents Sandia National Laboratories (SNL) portion of a collaborative three-year project with Northrop Grumman Electronic Systems (NGES) and the University of Missouri to develop an advanced, thermal ground-plane (TGP), which is a device, of planar configuration, that delivers heat from a source to an ambient environment with high efficiency. Work at all three institutions was funded by DARPA/MTO; Sandia was funded under DARPA/MTO project number 015070924. This is the final report on this project for SNL. This report presents a numerical model of a pulsating heat pipe, a device employing a two phase (liquid and its vapor) working fluid confined in a closed loop channel etched/milled into a serpentine configuration in a solid metal plate. The device delivers heat from an evaporator (hot zone) to a condenser (cold zone). This new model includes key physical processes important to the operation of flat plate pulsating heat pipes (e.g. dynamic bubble nucleation, evaporation and condensation), together with conjugate heat transfer with the solid portion of the device. The model qualitatively and quantitatively predicts performance characteristics and metrics, which was demonstrated by favorable comparisons with experimental results on similar configurations. Application of the model also corroborated many previous performance observations with respect to key parameters such as heat load, fill ratio and orientation.
Efficiently modeling neural networks on massively parallel computers
Farber, Robert M.
1993-01-01
Neural networks are a very useful tool for analyzing and modeling complex real world systems. Applying neural network simulations to real world problems generally involves large amounts of data and massive amounts of computation. To efficiently handle the computational requirements of large problems, we have implemented at Los Alamos a highly efficient neural network compiler for serial computers, vector computers, vector parallel computers, and fine grain SIMD computers such as the CM-2 connection machine. This paper describes the mapping used by the compiler to implement feed-forward backpropagation neural networks for a SIMD (Single Instruction Multiple Data) architecture parallel computer. Thinking Machines Corporation has benchmarked our code at 1.3 billion interconnects per second (approximately 3 gigaflops) on a 64,000 processor CM-2 connection machine (Singer 1990). This mapping is applicable to other SIMD computers and can be implemented on MIMD computers such as the CM-5 connection machine. Our mapping has virtually no communications overhead with the exception of the communications required for a global summation across the processors (which has a sub-linear runtime growth on the order of O(log(number of processors)). We can efficiently model very large neural networks which have many neurons and interconnects and our mapping can extend to arbitrarily large networks (within memory limitations) by merging the memory space of separate processors with fast adjacent processor interprocessor communications. This paper will consider the simulation of only feed forward neural network although this method is extendable to recurrent networks.
Improved Computational Model of Grid Cells Based on Column Structure
Institute of Scientific and Technical Information of China (English)
Yang Zhou; Dewei Wu; Weilong Li; Jia Du
2016-01-01
To simulate the firing pattern of biological grid cells, this paper presents an improved computational model of grid cells based on column structure. In this model, the displacement along different directions is processed by modulus operation, and the obtained remainder is associated with firing rate of grid cell. Compared with the original model, the improved parts include that: the base of modulus operation is changed, and the firing rate in firing field is encoded by Gaussian⁃like function. Simulation validates that the firing pattern generated by the improved computational model is more consistent with biological characteristic than original model. Besides, the firing pattern is badly influenced by the cumulative positioning error, but the computational model can also generate the regularly hexagonal firing pattern when the real⁃time positioning results are modified.
Computer Models Simulate Fine Particle Dispersion
2010-01-01
Through a NASA Seed Fund partnership with DEM Solutions Inc., of Lebanon, New Hampshire, scientists at Kennedy Space Center refined existing software to study the electrostatic phenomena of granular and bulk materials as they apply to planetary surfaces. The software, EDEM, allows users to import particles and obtain accurate representations of their shapes for modeling purposes, such as simulating bulk solids behavior, and was enhanced to be able to more accurately model fine, abrasive, cohesive particles. These new EDEM capabilities can be applied in many industries unrelated to space exploration and have been adopted by several prominent U.S. companies, including John Deere, Pfizer, and Procter & Gamble.
Computational social network modeling of terrorist recruitment.
Energy Technology Data Exchange (ETDEWEB)
Berry, Nina M.; Turnley, Jessica Glicken (Sandia National Laboratories, Albuquerque, NM); Smrcka, Julianne D. (Sandia National Laboratories, Albuquerque, NM); Ko, Teresa H.; Moy, Timothy David (Sandia National Laboratories, Albuquerque, NM); Wu, Benjamin C.
2004-10-01
The Seldon terrorist model represents a multi-disciplinary approach to developing organization software for the study of terrorist recruitment and group formation. The need to incorporate aspects of social science added a significant contribution to the vision of the resulting Seldon toolkit. The unique addition of and abstract agent category provided a means for capturing social concepts like cliques, mosque, etc. in a manner that represents their social conceptualization and not simply as a physical or economical institution. This paper provides an overview of the Seldon terrorist model developed to study the formation of cliques, which are used as the major recruitment entity for terrorist organizations.
Computer Models and Automata Theory in Biology and Medicine
Baianu, I C
2004-01-01
The applications of computers to biological and biomedical problem solving goes back to the very beginnings of computer science, automata theory [1], and mathematical biology [2]. With the advent of more versatile and powerful computers, biological and biomedical applications of computers have proliferated so rapidly that it would be virtually impossible to compile a comprehensive review of all developments in this field. Limitations of computer simulations in biology have also come under close scrutiny, and claims have been made that biological systems have limited information processing power [3]. Such general conjectures do not, however, deter biologists and biomedical researchers from developing new computer applications in biology and medicine. Microprocessors are being widely employed in biological laboratories both for automatic data acquisition/processing and modeling; one particular area, which is of great biomedical interest, involves fast digital image processing and is already established for rout...
M. Kasemann
Overview In autumn the main focus was to process and handle CRAFT data and to perform the Summer08 MC production. The operational aspects were well covered by regular Computing Shifts, experts on duty and Computing Run Coordination. At the Computing Resource Board (CRB) in October a model to account for service work at Tier 2s was approved. The computing resources for 2009 were reviewed for presentation at the C-RRB. The quarterly resource monitoring is continuing. Facilities/Infrastructure operations Operations during CRAFT data taking ran fine. This proved to be a very valuable experience for T0 workflows and operations. The transfers of custodial data to most T1s went smoothly. A first round of reprocessing started at the Tier-1 centers end of November; it will take about two weeks. The Computing Shifts procedure was tested full scale during this period and proved to be very efficient: 30 Computing Shifts Persons (CSP) and 10 Computing Resources Coordinators (CRC). The shift program for the shut down w...
Application of computer simulated persons in indoor environmental modeling
DEFF Research Database (Denmark)
Topp, C.; Nielsen, P. V.; Sørensen, Dan Nørtoft
2002-01-01
Computer simulated persons are often applied when the indoor environment is modeled by computational fluid dynamics. The computer simulated persons differ in size, shape, and level of geometrical complexity, ranging from simple box or cylinder shaped heat sources to more humanlike models. Little...... effort, however, has been focused on the influence of the geometry. This work provides an investigation of geometrically different computer simulated persons with respect to both local and global airflow distribution. The results show that a simple geometry is sufficient when the global airflow...... of a ventilated enclosure is considered, as little or no influence of geometry was observed at some distance from the computer simulated person. For local flow conditions, though, a more detailed geometry should be applied in order to assess thermal and atmospheric comfort....
Complex system modelling and control through intelligent soft computations
Azar, Ahmad
2015-01-01
The book offers a snapshot of the theories and applications of soft computing in the area of complex systems modeling and control. It presents the most important findings discussed during the 5th International Conference on Modelling, Identification and Control, held in Cairo, from August 31-September 2, 2013. The book consists of twenty-nine selected contributions, which have been thoroughly reviewed and extended before their inclusion in the volume. The different chapters, written by active researchers in the field, report on both current theories and important applications of soft-computing. Besides providing the readers with soft-computing fundamentals, and soft-computing based inductive methodologies/algorithms, the book also discusses key industrial soft-computing applications, as well as multidisciplinary solutions developed for a variety of purposes, like windup control, waste management, security issues, biomedical applications and many others. It is a perfect reference guide for graduate students, r...
Practical Use of Computationally Frugal Model Analysis Methods.
Hill, Mary C; Kavetski, Dmitri; Clark, Martyn; Ye, Ming; Arabi, Mazdak; Lu, Dan; Foglia, Laura; Mehl, Steffen
2016-03-01
Three challenges compromise the utility of mathematical models of groundwater and other environmental systems: (1) a dizzying array of model analysis methods and metrics make it difficult to compare evaluations of model adequacy, sensitivity, and uncertainty; (2) the high computational demands of many popular model analysis methods (requiring 1000's, 10,000 s, or more model runs) make them difficult to apply to complex models; and (3) many models are plagued by unrealistic nonlinearities arising from the numerical model formulation and implementation. This study proposes a strategy to address these challenges through a careful combination of model analysis and implementation methods. In this strategy, computationally frugal model analysis methods (often requiring a few dozen parallelizable model runs) play a major role, and computationally demanding methods are used for problems where (relatively) inexpensive diagnostics suggest the frugal methods are unreliable. We also argue in favor of detecting and, where possible, eliminating unrealistic model nonlinearities-this increases the realism of the model itself and facilitates the application of frugal methods. Literature examples are used to demonstrate the use of frugal methods and associated diagnostics. We suggest that the strategy proposed in this paper would allow the environmental sciences community to achieve greater transparency and falsifiability of environmental models, and obtain greater scientific insight from ongoing and future modeling efforts. PMID:25810333
Trusting explanatory and exploratory models in computational geomorphology
Van De Wiel, Marco; Desjardins, Eric; Rousseau, Yannick; Martel, Tristan; Ashmore, Peter
2014-05-01
Computer simulations have become an increasingly important part of geomorphological investigation in the last decades. Simulations can be used not only to make specific predictions of the evolution of a geomorphic system (predictive modelling), but also to test theories and learn about geomorphic form and process in a timely and non destructive way (explanatory and exploratory modelling). The latter modes of modelling can be very useful for discovering spatial and temporal patterns, developing insights in the relation between form and process, and for understanding the causal structure of the physical landscape. But before we can have any hope that these type of simulations can effectively accomplish these tasks, simulationists must make the case that their computer modelling goes beyond mere numerical computation of theoretical idealization; that geomorphic investigation through computer modelling can play a similar role as field observation or laboratory experiment. Many of these explanatory and exploratory models are reduced-complexity models which exhibit a high degree of idealization and simplification. Moreover, they are often uncalibrated and untested on real geomorphic systems. Indeed, they are often used on idealized hypothetical landscapes, and sometimes are acknowledged not to be suitable for simulation of real systems. Does it make sense then to conceive of this type of computer modelling as a form of investigation capable of providing reliable knowledge about actual geomorphological phenomena? In this analysis it is argued that the traditional notion of establishing reliability or trustworthiness of models, i.e. a confirmation of predictive ability with regards to observed data, is not applicable to explanatory or exploratory modelling. Instead, trustworthiness of these models is established through broad qualitative conformity with known system dynamics, followed by a posteriori field and laboratory testing of hypotheses generated from the modelling
Software Reliability Modeling using Soft Computing Techniques: Critical Review
Directory of Open Access Journals (Sweden)
Kuldeep Singh Kaswan
2015-06-01
Full Text Available Software reliability models assess the reliability by predicting faults for the software. Reliability is a real world phenomenon with many associated real-time problems. To obtain solutions to problems quickly, accurately and acceptably, a large number of soft computing techniques have been developed, but it is very difficult to find out which one is the most suitable and can be used globally. In this paper, we have provided an overview of existing soft computing techniques, and then critically analyzed the work done by the various researchers in the field of software reliability. Further to this, we have also compared soft computing techniques in terms of software reliability modeling capabilities.
Global Stability of an Epidemic Model of Computer Virus
Directory of Open Access Journals (Sweden)
Xiaofan Yang
2014-01-01
Full Text Available With the rapid popularization of the Internet, computers can enter or leave the Internet increasingly frequently. In fact, no antivirus software can detect and remove all sorts of computer viruses. This implies that viruses would persist on the Internet. To better understand the spread of computer viruses in these situations, a new propagation model is established and analyzed. The unique equilibrium of the model is globally asymptotically stable, in accordance with the reality. A parameter analysis of the equilibrium is also conducted.
Implementation of CCNUGrid-based Computational Environment for Molecular Modeling
Liu, Kai; Luo, Changhua; Ren, Yanliang; Wan, Jian; Xu, Xin
2007-12-01
Grid computing technology has being regarded as one of the most promising solutions for the tremendous requirement of computing resources in the field of molecular modeling up to date. Contrast to building a more and more powerful super-computer with novel hardware in a local network, grid technology enable us, in principle, to integrate various previous and present computing resources located in different location into a computing platform as a whole. As a case demonstration, we reported herein that a campus grid entitled CCNUGrid was implemented with grid middleware, consisting of four local computing networks distributed in College of Chemistry, College of Physics, Center for Network, and Center for Education Information Technology and Engineering, respectively, at Central China Normal University. Visualization functions of monitoring computer machines in each local network, monitoring job processing flow, and monitoring computational results were realized in this campus grid-based computational environment, in addition to the conventional components of grid architecture: universal portal, task management, computing node and security. In the last section of this paper, a molecular docking-based virtual screening study was performed at the CCNUGrid, as one example of CCNUGrid applications.
Emotion in Music: representation and computational modeling
Aljanaki, A.
2016-01-01
Music emotion recognition (MER) deals with music classification by emotion using signal processing and machine learning techniques. Emotion ontology for music is not well established yet. Musical emotion can be conceptualized through various emotional models: categorical, dimensional, or domain-spec
Modeling Astrophysical Explosions with Sustained Exascale Computing
Zingale, M; Malone, C M; Timmes, F X
2015-01-01
Our understanding of stars and their fates is based on coupling observations to theoretical models. Unlike laboratory physicists, we cannot perform experiments on stars, but rather must patiently take what nature allows us to observe. Simulation offers a means of virtual experimentation, enabling a detailed understanding of the most violent ongoing explosions in the Universe---the deaths of stars.
Computational Modeling of Fluorescence Loss in Photobleaching
DEFF Research Database (Denmark)
Hansen, Christian Valdemar; Schroll, Achim; Wüstner, Daniel
2015-01-01
sequences as reaction– diffusion systems on segmented cell images. The cell geometry is extracted from microscopy images using the Chan–Vese active contours algorithm [8]. The PDE model is subsequently solved by the automated Finite Element software package FEniCS [20]. The flexibility of FEniCS allows...
Computational Modeling Develops Ultra-Hard Steel
2007-01-01
Glenn Research Center's Mechanical Components Branch developed a spiral bevel or face gear test rig for testing thermal behavior, surface fatigue, strain, vibration, and noise; a full-scale, 500-horsepower helicopter main-rotor transmission testing stand; a gear rig that allows fundamental studies of the dynamic behavior of gear systems and gear noise; and a high-speed helical gear test for analyzing thermal behavior for rotorcraft. The test rig provides accelerated fatigue life testing for standard spur gears at speeds of up to 10,000 rotations per minute. The test rig enables engineers to investigate the effects of materials, heat treat, shot peen, lubricants, and other factors on the gear's performance. QuesTek Innovations LLC, based in Evanston, Illinois, recently developed a carburized, martensitic gear steel with an ultra-hard case using its computational design methodology, but needed to verify surface fatigue, lifecycle performance, and overall reliability. The Battelle Memorial Institute introduced the company to researchers at Glenn's Mechanical Components Branch and facilitated a partnership allowing researchers at the NASA Center to conduct spur gear fatigue testing for the company. Testing revealed that QuesTek's gear steel outperforms the current state-of-the-art alloys used for aviation gears in contact fatigue by almost 300 percent. With the confidence and credibility provided by the NASA testing, QuesTek is commercializing two new steel alloys. Uses for this new class of steel are limitless in areas that demand exceptional strength for high throughput applications.
Scratch as a computational modelling tool for teaching physics
Lopez, Victor; Hernandez, Maria Isabel
2015-05-01
The Scratch online authoring tool, which features a simple programming language that has been adapted to primary and secondary students, is being used more and more in schools as it offers students and teachers the opportunity to use a tool to build scientific models and evaluate their behaviour, just as can be done with computational modelling programs. In this article, we briefly discuss why Scratch could be a useful tool for computational modelling in the primary or secondary physics classroom, and we present practical examples of how it can be used to build a model.
Topologies of Stochastic Markov Models: Computational Aspects
Bacci, Giorgio; Bacci, Giovanni; Larsen, Kim G.; Mardare, Radu
2014-01-01
In this paper we propose two behavioral distances that support approximate reasoning on Stochastic Markov Models (SMMs), that are continuous-time stochastic transition systems where the residence time on each state is described by a generic probability measure on the positive real line. In particular, we study the problem of measuring the behavioral dissimilarity of two SMMs against linear real-time specifications expressed as Metric Temporal Logic (MTL) formulas or Deterministic Timed-Automa...
Pialasse, Jean-Philippe; Descarreaux, Martin; Mercier, Pierre; Simoneau, Martin
2015-10-01
Idiopathic scoliosis is the most frequent spinal deformity in adolescence. While its aetiology remains unclear, impairments in balance control suggest a dysfunction of the sensorimotor control mechanisms. The objective of this paper is to evaluate the ability of patients with idiopathic scoliosis to reweigh sensory information. Using a neuromechanical model, the relative sensory weighting of vestibular and proprioceptive information was assessed. Sixteen healthy adolescents and respectively 20 and 16 adolescents with mild or severe scoliosis were recruited. Binaural bipolar galvanic vestibular stimulation was delivered to elicit postural movement along the coronal plane. The kinematics of the upper body, using normalized horizontal displacement of the 7th cervical vertebra, was recorded 1s before, 2s during, and 1s following vestibular stimulation. The neuromechanical model included active feedback mechanisms that generated corrective torque from the vestibular and proprioceptive error signals. The model successfully predicted the normalized horizontal displacement of the 7th cervical vertebra. All groups showed similar balance control before vestibular stimulation; however, the amplitude (i.e., peak horizontal displacement) of the body sway during and immediately following vestibular stimulation was approximately 3 times larger in patients compared to control adolescents. The outcome of the model revealed that patients assigned a larger weight to vestibular information compared to controls; vestibular weight was 6.03% for controls, whereas it was 13.09% and 13.26% for the mild and severe scoliosis groups, respectively. These results suggest that despite the amplitude of spine deformation, the sensory reweighting mechanism is altered similarly in adolescent patients with scoliosis. PMID:26371828
A Lumped Computational Model for Sodium Sulfur Battery Analysis
Wu, Fan
Due to the cost of materials and time consuming testing procedures, development of new batteries is a slow and expensive practice. The purpose of this study is to develop a computational model and assess the capabilities of such a model designed to aid in the design process and control of sodium sulfur batteries. To this end, a transient lumped computational model derived from an integral analysis of the transport of species, energy and charge throughout the battery has been developed. The computation processes are coupled with the use of Faraday's law, and solutions for the species concentrations, electrical potential and current are produced in a time marching fashion. Properties required for solving the governing equations are calculated and updated as a function of time based on the composition of each control volume. The proposed model is validated against multi- dimensional simulations and experimental results from literatures, and simulation results using the proposed model is presented and analyzed. The computational model and electrochemical model used to solve the equations for the lumped model are compared with similar ones found in the literature. The results obtained from the current model compare favorably with those from experiments and other models.
Integrated Multiscale Modeling of Molecular Computing Devices
Energy Technology Data Exchange (ETDEWEB)
Gregory Beylkin
2012-03-23
Significant advances were made on all objectives of the research program. We have developed fast multiresolution methods for performing electronic structure calculations with emphasis on constructing efficient representations of functions and operators. We extended our approach to problems of scattering in solids, i.e. constructing fast algorithms for computing above the Fermi energy level. Part of the work was done in collaboration with Robert Harrison and George Fann at ORNL. Specific results (in part supported by this grant) are listed here and are described in greater detail. (1) We have implemented a fast algorithm to apply the Green's function for the free space (oscillatory) Helmholtz kernel. The algorithm maintains its speed and accuracy when the kernel is applied to functions with singularities. (2) We have developed a fast algorithm for applying periodic and quasi-periodic, oscillatory Green's functions and those with boundary conditions on simple domains. Importantly, the algorithm maintains its speed and accuracy when applied to functions with singularities. (3) We have developed a fast algorithm for obtaining and applying multiresolution representations of periodic and quasi-periodic Green's functions and Green's functions with boundary conditions on simple domains. (4) We have implemented modifications to improve the speed of adaptive multiresolution algorithms for applying operators which are represented via a Gaussian expansion. (5) We have constructed new nearly optimal quadratures for the sphere that are invariant under the icosahedral rotation group. (6) We obtained new results on approximation of functions by exponential sums and/or rational functions, one of the key methods that allows us to construct separated representations for Green's functions. (7) We developed a new fast and accurate reduction algorithm for obtaining optimal approximation of functions by exponential sums and/or their rational representations.
Computational Modeling of T Cell Receptor Complexes.
Riley, Timothy P; Singh, Nishant K; Pierce, Brian G; Weng, Zhiping; Baker, Brian M
2016-01-01
T-cell receptor (TCR) binding to peptide/MHC determines specificity and initiates signaling in antigen-specific cellular immune responses. Structures of TCR-pMHC complexes have provided enormous insight to cellular immune functions, permitted a rational understanding of processes such as pathogen escape, and led to the development of novel approaches for the design of vaccines and other therapeutics. As production, crystallization, and structure determination of TCR-pMHC complexes can be challenging, there is considerable interest in modeling new complexes. Here we describe a rapid approach to TCR-pMHC modeling that takes advantage of structural features conserved in known complexes, such as the restricted TCR binding site and the generally conserved diagonal docking mode. The approach relies on the powerful Rosetta suite and is implemented using the PyRosetta scripting environment. We show how the approach can recapitulate changes in TCR binding angles and other structural details, and highlight areas where careful evaluation of parameters is needed and alternative choices might be made. As TCRs are highly sensitive to subtle structural perturbations, there is room for improvement. Our method nonetheless generates high-quality models that can be foundational for structure-based hypotheses regarding TCR recognition. PMID:27094300
Computational modeling of leukocyte adhesion cascade (LAC)
Sarkar, Kausik
2005-11-01
In response to an inflammation in the body, leukocytes (white blood cell) interact with the endothelium (interior wall of blood vessel) through a series of steps--capture, rolling, adhesion and transmigration--critical for proper functioning of the immune system. We are numerically simulating this process using a Front-tracking finite-difference method. The viscoelastcity of the cell membrane, cytoplasm and nucleus are incorporated and allowed to change with time in response to the cell surface molecular chemistry. The molecular level forces due to specific ligand-receptor interactions are accounted for by stochastic spring-peeling model. Even though leukocyte rolling has been investigated through various models, the transitioning through subsequent steps, specifically firm adhesion and transmigration through endothelial layer, has not been modeled. The change of viscoelastic properties due to the leukocyte activation is observed to play a critical role in mediating the transition from rolling to transmigration. We will provide details of our approach and discuss preliminary results.
Computational mathematics models, methods, and analysis with Matlab and MPI
White, Robert E
2004-01-01
Computational Mathematics: Models, Methods, and Analysis with MATLAB and MPI explores and illustrates this process. Each section of the first six chapters is motivated by a specific application. The author applies a model, selects a numerical method, implements computer simulations, and assesses the ensuing results. These chapters include an abundance of MATLAB code. By studying the code instead of using it as a "black box, " you take the first step toward more sophisticated numerical modeling. The last four chapters focus on multiprocessing algorithms implemented using message passing interface (MPI). These chapters include Fortran 9x codes that illustrate the basic MPI subroutines and revisit the applications of the previous chapters from a parallel implementation perspective. All of the codes are available for download from www4.ncsu.edu./~white.This book is not just about math, not just about computing, and not just about applications, but about all three--in other words, computational science. Whether us...
Enabling Grid Computing resources within the KM3NeT computing model
Directory of Open Access Journals (Sweden)
Filippidis Christos
2016-01-01
Full Text Available KM3NeT is a future European deep-sea research infrastructure hosting a new generation neutrino detectors that – located at the bottom of the Mediterranean Sea – will open a new window on the universe and answer fundamental questions both in particle physics and astrophysics. International collaborative scientific experiments, like KM3NeT, are generating datasets which are increasing exponentially in both complexity and volume, making their analysis, archival, and sharing one of the grand challenges of the 21st century. These experiments, in their majority, adopt computing models consisting of different Tiers with several computing centres and providing a specific set of services for the different steps of data processing such as detector calibration, simulation and data filtering, reconstruction and analysis. The computing requirements are extremely demanding and, usually, span from serial to multi-parallel or GPU-optimized jobs. The collaborative nature of these experiments demands very frequent WAN data transfers and data sharing among individuals and groups. In order to support the aforementioned demanding computing requirements we enabled Grid Computing resources, operated by EGI, within the KM3NeT computing model. In this study we describe our first advances in this field and the method for the KM3NeT users to utilize the EGI computing resources in a simulation-driven use-case.
Enabling Grid Computing resources within the KM3NeT computing model
Filippidis, Christos
2016-04-01
KM3NeT is a future European deep-sea research infrastructure hosting a new generation neutrino detectors that - located at the bottom of the Mediterranean Sea - will open a new window on the universe and answer fundamental questions both in particle physics and astrophysics. International collaborative scientific experiments, like KM3NeT, are generating datasets which are increasing exponentially in both complexity and volume, making their analysis, archival, and sharing one of the grand challenges of the 21st century. These experiments, in their majority, adopt computing models consisting of different Tiers with several computing centres and providing a specific set of services for the different steps of data processing such as detector calibration, simulation and data filtering, reconstruction and analysis. The computing requirements are extremely demanding and, usually, span from serial to multi-parallel or GPU-optimized jobs. The collaborative nature of these experiments demands very frequent WAN data transfers and data sharing among individuals and groups. In order to support the aforementioned demanding computing requirements we enabled Grid Computing resources, operated by EGI, within the KM3NeT computing model. In this study we describe our first advances in this field and the method for the KM3NeT users to utilize the EGI computing resources in a simulation-driven use-case.
International Nuclear Information System (INIS)
The Committee, asked to provide an assessment of computer-assisted modeling of molecular structure, has highlighted the signal successes and the significant limitations for a broad panoply of technologies and has projected plausible paths of development over the next decade. As with any assessment of such scope, differing opinions about present or future prospects were expressed. The conclusions and recommendations, however, represent a consensus of our views of the present status of computational efforts in this field
The role of computer modelling in participatory integrated assessments
International Nuclear Information System (INIS)
In a number of recent research projects, computer models have been included in participatory procedures to assess global environmental change. The intention was to support knowledge production and to help the involved non-scientists to develop a deeper understanding of the interactions between natural and social systems. This paper analyses the experiences made in three projects with the use of computer models from a participatory and a risk management perspective. Our cross-cutting analysis of the objectives, the employed project designs and moderation schemes and the observed learning processes in participatory processes with model use shows that models play a mixed role in informing participants and stimulating discussions. However, no deeper reflection on values and belief systems could be achieved. In terms of the risk management phases, computer models serve best the purposes of problem definition and option assessment within participatory integrated assessment (PIA) processes
A distributed computing model for telemetry data processing
Barry, Matthew R.; Scott, Kevin L.; Weismuller, Steven P.
1994-05-01
We present a new approach to distributing processed telemetry data among spacecraft flight controllers within the control centers at NASA's Johnson Space Center. This approach facilitates the development of application programs which integrate spacecraft-telemetered data and ground-based synthesized data, then distributes this information to flight controllers for analysis and decision-making. The new approach combines various distributed computing models into one hybrid distributed computing model. The model employs both client-server and peer-to-peer distributed computing models cooperating to provide users with information throughout a diverse operations environment. Specifically, it provides an attractive foundation upon which we are building critical real-time monitoring and control applications, while simultaneously lending itself to peripheral applications in playback operations, mission preparations, flight controller training, and program development and verification. We have realized the hybrid distributed computing model through an information sharing protocol. We shall describe the motivations that inspired us to create this protocol, along with a brief conceptual description of the distributed computing models it employs. We describe the protocol design in more detail, discussing many of the program design considerations and techniques we have adopted. Finally, we describe how this model is especially suitable for supporting the implementation of distributed expert system applications.
Paradox of integration -- a computational model
Krawczyk, Malgorzata J
2016-01-01
The paradoxical aspect of integration of a social group has been highlighted by Peter Blau (Exchange and Power in Social Life, Wiley and Sons, 1964). During the integration process, the group members simultaneously compete for social status and play the role of the audience. Here we show that when the competition prevails over the desire of approval, a sharp transition breaks all friendly relations. However, as was described by Blau, people with high status are inclined to bother more with acceptance of others; this is achieved by praising others and revealing her/his own weak points. In our model, this action smooths the transition and improves interpersonal relations.
Directory of Open Access Journals (Sweden)
D. J. McNeall
2013-10-01
Full Text Available We measure the potential of an observational data set to constrain a set of inputs to a complex and computationally expensive computer model. We use each member in turn of an ensemble of output from a computationally expensive model, corresponding to an observable part of a modelled system, as a proxy for an observational data set. We argue that, given some assumptions, our ability to constrain uncertain parameter inputs to a model using its own output as data, provides a maximum bound for our ability to constrain the model inputs using observations of the real system. The ensemble provides a set of known parameter input and model output pairs, which we use to build a computationally efficient statistical proxy for the full computer model, termed an emulator. We use the emulator to find and rule out "implausible" values for the inputs of held-out ensemble members, given the computer model output. As we know the true values of the inputs for the ensemble, we can compare our constraint of the model inputs with the true value of the input for any ensemble member. Measures of the quality of constraint have the potential to inform strategy for data collection campaigns, before any real-world data is collected, as well as acting as an effective sensitivity analysis. We use an ensemble of the ice sheet model Glimmer to demonstrate our measures of quality of constraint. The ensemble has 250 model runs with 5 uncertain input parameters, and an output variable representing the pattern of the thickness of ice over Greenland. We have an observation of historical ice sheet thickness that directly matches the output variable, and offers an opportunity to constrain the model. We show that different ways of summarising our output variable (ice volume, ice surface area and maximum ice thickness offer different potential constraints on individual input parameters. We show that combining the observational data gives increased power to constrain the model. We
Directory of Open Access Journals (Sweden)
D. J. McNeall
2013-04-01
Full Text Available We measure the potential of an observational data set to constrain a set of inputs to a complex and computationally expensive computer model. We use each member in turn of an ensemble of output from a computationally expensive model, corresponding to some observable part of a modelled system, as a proxy for an observational data set. We argue that our ability to constrain uncertain parameter inputs to a model using its own output as data, provides a maximum bound for our ability to constrain the model inputs using observations of the real system. The ensemble provides a set of known parameter input and model output pairs, which we use to build a computationally efficient statistical proxy for the full computer model, termed an emulator. We use the emulator to find and rule out ''implausible" values for the inputs of held-out ensemble members, given the computer model output. As we know the true values of the inputs for the ensemble, we can compare our constraint of the model inputs with the true value of the input for any ensemble member. Measures of the quality of constraint have the potential to inform strategy for data collection campaigns, before any real-world data is collected, as well as acting as an effective sensitivity analysis. We use an ensemble of the ice sheet model Glimmer to demonstrate our measures of quality of constraint. The ensemble has 250 model runs with 5 uncertain input parameters, and an output variable representing the pattern of the thickness of ice over Greenland. We have an observation of historical ice sheet thickness that directly matches the output variable, and offers an opportunity to constrain the model. We show that different ways of summarising our output variable (ice volume, ice surface area and maximum ice thickness offer different potential constraints on individual input parameters. We show that combining the observational data gives increased power to constrain the model. We investigate the impact of
Adapting an evidence-based model to retain adolescent study participants in longitudinal research.
Davis, Erin; Demby, Hilary; Jenner, Lynne Woodward; Gregory, Alethia; Broussard, Marsha
2016-02-01
Maintaining contact with and collecting outcome data from adolescent study participants can present a significant challenge for researchers conducting longitudinal studies. Establishing an organized and effective protocol for participant follow-up is crucial to reduce attrition and maintain high retention rates. This paper describes our methods in using and adapting the evidence-based Engagement, Verification, Maintenance, and Confirmation (EVMC) model to follow up with adolescents 6 and 12 months after implementation of a health program. It extends previous research by focusing on two key modifications to the model: (1) the central role of cell phones and texting to maintain contact with study participants throughout the EVMC process and, (2) use of responsive two-way communication between staff and participants and flexible administration modes and methods in the confirmation phase to ensure that busy teens not only respond to contacts, but also complete data collection. These strategies have resulted in high overall retention rates (87-91%) with adolescent study participants at each follow-up data collection point without the utilization of other, more involved tracking measures. The methods and findings presented may be valuable for other researchers with limited resources planning for or engaged in collecting follow-up outcome data from adolescents enrolled in longitudinal studies. PMID:26539953
Flexing Computational Muscle: Modeling and Simulation of Musculotendon Dynamics
Millard, Matthew; Uchida, Thomas; Seth, Ajay; Delp, Scott L.
2013-01-01
Muscle-driven simulations of human and animal motion are widely used to complement physical experiments for studying movement dynamics. Musculotendon models are an essential component of muscle-driven simulations, yet neither the computational speed nor the biological accuracy of the simulated forces has been adequately evaluated. Here we compare the speed and accuracy of three musculotendon models: two with an elastic tendon (an equilibrium model and a damped equilibrium model) and one with ...
COMPUTATION OF GREEKS FOR JUMP-DIFFUSION MODELS
M'Hamed Eddahbi; SIDI MOHAMED LALAOUI BEN CHERIF; ABDELAZIZ NASROALLAH
2015-01-01
In the present paper, we compute the Greeks for a class of jump diffusion models by using Malliavin calculus techniques. More precisely, the model under consideration is governed by a Brownian component and a jump part described by a compound Poisson process. Our approach consists of approximating the compound Poisson process by a suitable sequence of standard Poisson processes. The Greeks of the original model are obtained as limits or weighted limits of the Greeks of the approximate model. ...
Emerging Trends and Statistical Analysis in Computational Modeling in Agriculture
Directory of Open Access Journals (Sweden)
Sunil Kumar
2015-03-01
Full Text Available In this paper the authors have tried to describe emerging trend in computational modelling used in the sphere of agriculture. Agricultural computational modelling with the use of intelligence techniques for computing the agricultural output by providing minimum input data to lessen the time through cutting down the multi locational field trials and also the labours and other inputs is getting momentum. Development of locally suitable integrated farming systems (IFS is the utmost need of the day, particularly in India where about 95% farms are under small and marginal holding size. Optimization of the size and number of the various enterprises to the desired IFS model for a particular set of agro-climate is essential components of the research to sustain the agricultural productivity for not only filling the stomach of the bourgeoning population of the country, but also to enhance the nutritional security and farms return for quality life. Review of literature pertaining to emerging trends in computational modelling applied in field of agriculture is done and described below for the purpose of understanding its trends mechanism behavior and its applications. Computational modelling is increasingly effective for designing and analysis of the system. Computa-tional modelling is an important tool to analyses the effect of different scenarios of climate and management options on the farming systems and its interaction among themselves. Further, authors have also highlighted the applications of computational modeling in integrated farming system, crops, weather, soil, climate, horticulture and statistical used in agriculture which can show the path to the agriculture researcher and rural farming community to replace some of the traditional techniques.
Computational Modeling of Cell Survival Using VHDL
Directory of Open Access Journals (Sweden)
Shruti Jain1,
2010-01-01
Full Text Available The model for cell survival has been implemented using VeryHigh Speed Integrated Circuit Hardware DescriptionLanguage (VHDL (Xilinx Tool taking three input signals:Tumor necrosis factor-α (TNF, Epidermal growth factor(EGF and Insulin. Cell survival has been regulated by theinteraction of five proteins viz P13K, TNFR1, EGFR, IRS andIKK in a network. In the absence of any one, in protein networkleads to cell death. For the EGF input signal the proteins likeMEK, ERK, AkT, Rac & JNK have been important forregulation of cell survival. Similarly for TNF and Insulin inputsignal proteins like NFκB, AkT, XIAP, JNK, MAP3K & MK2and MEK, ERK, AkT, Rac, mTOR & JNK respectively havebeen important for regulation of cell survival.
Computer Forensics Field Triage Process Model
Directory of Open Access Journals (Sweden)
Marcus K. Rogers
2006-06-01
Full Text Available With the proliferation of digital based evidence, the need for the timely identification, analysis and interpretation of digital evidence is becoming more crucial. In many investigations critical information is required while at the scene or within a short period of time - measured in hours as opposed to days. The traditional cyber forensics approach of seizing a system(s/media, transporting it to the lab, making a forensic image(s, and then searching the entire system for potential evidence, is no longer appropriate in some circumstances. In cases such as child abductions, pedophiles, missing or exploited persons, time is of the essence. In these types of cases, investigators dealing with the suspect or crime scene need investigative leads quickly; in some cases it is the difference between life and death for the victim(s. The Cyber Forensic Field Triage Process Model (CFFTPM proposes an onsite or field approach for providing the identification, analysis and interpretation of digital evidence in a short time frame, without the requirement of having to take the system(s/media back to the lab for an in-depth examination or acquiring a complete forensic image(s. The proposed model adheres to commonly held forensic principles, and does not negate the ability that once the initial field triage is concluded, the system(s/storage media be transported back to a lab environment for a more thorough examination and analysis. The CFFTPM has been successfully used in various real world cases, and its investigative importance and pragmatic approach has been amply demonstrated. Furthermore, the derived evidence from these cases has not been challenged in the court proceedings where it has been introduced. The current article describes the CFFTPM in detail, discusses the model’s forensic soundness, investigative support capabilities and practical considerations.
A computer model of glaze accretion on wires
Energy Technology Data Exchange (ETDEWEB)
Draganoiu, G.; Lamarche, L.; McComber, P. [Univ. of Quebec, Montreal, Quebec (Canada). Dept. of Mechanical Engineering
1996-05-01
The design of power transmission lines requires a knowledge of combined wind and ice loading and of the dynamic behavior of wires loaded with ice accretion. The calculation of the wind forces, in turn, imposes a need for a more detailed computer model for determining glaze accretion shape. For this purpose, a computer model of glaze accretion on wires was developed. It is based on experimental results in the area of ice accretion on wires, as well as on results in the related field of the glaze ice accretion on airfoils. The model incorporates the time dependent on feedback between the growing accretion and the air stream, the variation of the heat transfer coefficient around the cylinder, and the surface runback of water. The main components of the model are the computation of the air flow field, the computation of the impingement water at the control volume level, the solving of the heat balance equation, and the computation of the accretion shape on the wire. The surface air velocity is obtained through the solution of the potential flow around the iced wire and wake, followed by the integration on the surface of the laminar boundary layer. The water flux is computed in each control volume down to the separation point. The heat balance equation derived from the energy equation is solved to determine the freezing fraction and the resulting modified ice surface geometry.
Computational Modeling of the Electrochemical System of Lipase Activity Detection
Directory of Open Access Journals (Sweden)
Valdemaras Razumas
2008-06-01
Full Text Available This paper presents computational modeling of response kinetics of bioelectroanalytical system based on solid supported lipase substrate and lipase interaction. The model assumes that lipase substrate is formed by dripping and drying a small amount of the ethanol solution of 9-(5Ã¢Â€Â™-ferrocenylpentanoyloxynonyl disulfide (FPONDS and that lipase is capable of cleaving FPONDS ester bonds via hydrolysis mechanism. Two mathematical models have been developed and evaluated trough computational simulation series by comparing them to experimental data. The results of simulation demonstrate that a good fitting might be obtained only taking into account non-linear substrate wash off process.
A propagation model of computer virus with nonlinear vaccination probability
Gan, Chenquan; Yang, Xiaofan; Liu, Wanping; Zhu, Qingyi
2014-01-01
This paper is intended to examine the effect of vaccination on the spread of computer viruses. For that purpose, a novel computer virus propagation model, which incorporates a nonlinear vaccination probability, is proposed. A qualitative analysis of this model reveals that, depending on the value of the basic reproduction number, either the virus-free equilibrium or the viral equilibrium is globally asymptotically stable. The results of simulation experiments not only demonstrate the validity of our model, but also show the effectiveness of nonlinear vaccination strategies. Through parameter analysis, some effective strategies for eradicating viruses are suggested.
Generating Turing Machines by Use of Other Computation Models
Directory of Open Access Journals (Sweden)
Leszek Dubiel
2003-01-01
Full Text Available For each problem that can be solved there exists algorithm, which can be described with a program of Turing machine. Because this is very simple model programs tend to be very complicated and hard to analyse by human. The best practice to solve given type of problems is to define a new model of computation that allows for quick and easy programming, and then to emulate its operation with Turing machine. This article shows how to define most suitable model for computation on natural numbers and defines Turing machine that emulates its operation.
A Separated Domain-Based Kernel Model for Trusted Computing
Institute of Scientific and Technical Information of China (English)
FANG Yanxiang; SHEN Changxiang; XU Jingdong; WU Gongyi
2006-01-01
This paper fist gives an investigation on trusted computing on mainstream operation system (OS). Based on the observations, it is pointed out that Trusted Computing cannot be achieved due to the lack of separation mechanism of the components in mainstream OS. In order to provide a kind of separation mechanism, this paper proposes a separated domain-based kernel model (SDBKM), and this model is verified by non-interference theory. By monitoring and simplifying the trust dependence between domains, this model can solve problems in trust measurement such as deny of service (DoS) attack, Host security, and reduce the overhead of measurement.
A Multi-Agent Immunology Model for Security Computer
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
This paper presents a computer immunology model for computersecurity , whose main components are defined as idea of Multi-Agent. It introduces the n at ural immune system on the principle, discusses the idea and characteristics of Mu lti-Agent. It gives a system model, and describes the structure and function of each agent. Also, the communication method between agents is described.
Development of computer simulation models for pedestrian subsystem impact tests
Kant, R.; Konosu, A.; Ishikawa, H.
2000-01-01
The European Enhanced Vehicle-safety Committee (EEVC/WG10 and WG17) proposed three component subsystem tests for cars to assess pedestrian protection. The objective of this study is to develop computer simulation models of the EEVC pedestrian subsystem tests. These models are available to develop a
Operation of the computer model for microenvironment solar exposure
Gillis, J. R.; Bourassa, R. J.; Gruenbaum, P. E.
1995-01-01
A computer model for microenvironmental solar exposure was developed to predict solar exposure to satellite surfaces which may shadow or reflect on one another. This document describes the technical features of the model as well as instructions for the installation and use of the program.
Procedures for parameter estimates of computational models for localized failure
Iacono, C.
2007-01-01
In the last years, many computational models have been developed for tensile fracture in concrete. However, their reliability is related to the correct estimate of the model parameters, not all directly measurable during laboratory tests. Hence, the development of inverse procedures is needed, that
Computational and Game-Theoretic Approaches for Modeling Bounded Rationality
L. Waltman (Ludo)
2011-01-01
textabstractThis thesis studies various computational and game-theoretic approaches to economic modeling. Unlike traditional approaches to economic modeling, the approaches studied in this thesis do not rely on the assumption that economic agents behave in a fully rational way. Instead, economic age
Parameter Estimation for a Computable General Equilibrium Model
DEFF Research Database (Denmark)
Arndt, Channing; Robinson, Sherman; Tarp, Finn
We introduce a maximum entropy approach to parameter estimation for computable general equilibrium (CGE) models. The approach applies information theory to estimating a system of nonlinear simultaneous equations. It has a number of advantages. First, it imposes all general equilibrium constraints...... to estimating a CGE model of Mozambique...
A computer model for predicting grapevine cold hardiness
We developed a robust computer model of grapevine bud cold hardiness that will aid in the anticipation of and response to potential injury from fluctuations in winter temperature and from extreme cold events. The model uses time steps of 1 day along with the measured daily mean air temperature to ca...
Computational 3-D Model of the Human Respiratory System
We are developing a comprehensive, morphologically-realistic computational model of the human respiratory system that can be used to study the inhalation, deposition, and clearance of contaminants, while being adaptable for age, race, gender, and health/disease status. The model ...
Automatic Model Generation Framework for Computational Simulation of Cochlear Implantation
DEFF Research Database (Denmark)
Mangado Lopez, Nerea; Ceresa, Mario; Duchateau, Nicolas;
2015-01-01
Recent developments in computational modeling of cochlear implantation are promising to study in silico the performance of the implant before surgery. However, creating a complete computational model of the patient's anatomy while including an external device geometry remains challenging. To addr......Recent developments in computational modeling of cochlear implantation are promising to study in silico the performance of the implant before surgery. However, creating a complete computational model of the patient's anatomy while including an external device geometry remains challenging......'s CT image, an accurate model of the patient-specific cochlea anatomy is obtained. An algorithm based on the parallel transport frame is employed to perform the virtual insertion of the cochlear implant. Our automatic framework also incorporates the surrounding bone and nerve fibers and assigns...... constitutive parameters to all components of the finite element model. This model can then be used to study in silico the effects of the electrical stimulation of the cochlear implant. Results are shown on a total of 25 models of patients. In all cases, a final mesh suitable for finite element simulations...
Soliton laser: A computational two-cavity model
DEFF Research Database (Denmark)
Berg, P.; If, F.; Christiansen, Peter Leth;
1987-01-01
An improved computational two-cavity model of the soliton laser proposed and designed by Mollenauer and Stolen [Opt. Lett. 9, 13 (1984)] is obtained through refinements of (i) the laser cavity model, (ii) the pulse propagation in the fiber cavity, and (iii) the coupling between the two cavities. As...
LIME SPRAY DRYER FLUE GAS DESULFURIZATION COMPUTER MODEL USERS MANUAL
The report describes a lime spray dryer/baghouse (FORTRAN) computer model that simulates SO2 removal and permits study of related impacts on design and economics as functions of design parameters and operating conditions for coal-fired electric generating units. The model allows ...
Predicting room acoustical behavior with the ODEON computer model
DEFF Research Database (Denmark)
Naylor, Graham; Rindel, Jens Holger
1992-01-01
The computational bases of the ODEON model for room acoustics are described in a companion paper. The model is implemented for general use of a PC. In this paper, various technical features of the program relevant to the acoustical design process are presented. These include interactive visualiza...
Modeling and Computer Simulation of AN Insurance Policy:
Acharyya, Muktish; Acharyya, Ajanta Bhowal
We have developed a model for a life-insurance policy. In this model, the net gain is calculated by computer simulation for a particular type of lifetime distribution function. We observed that the net gain becomes maximum for a particular value of upper age for last premium.
Dynamic Distribution Model with Prime Granularity for Parallel Computing
Institute of Scientific and Technical Information of China (English)
无
2005-01-01
Dynamic distribution model is one of the best schemes for parallel volume rendering. However, in homogeneous cluster system, since the granularity is traditionally identical, all processors communicate almost simultaneously and computation load may lose balance. Due to problems above, a dynamic distribution model with prime granularity for parallel computing is presented.Granularities of each processor are relatively prime, and related theories are introduced. A high parallel performance can be achieved by minimizing network competition and using a load balancing strategy that ensures all processors finish almost simultaneously. Based on Master-Slave-Gleaner (MSG) scheme, the parallel Splatting Algorithm for volume rendering is used to test the model on IBM Cluster 1350 system. The experimental results show that the model can bring a considerable improvement in performance, including computation efficiency, total execution time, speed, and load balancing.
Computational modeling of neural activities for statistical inference
Kolossa, Antonio
2016-01-01
This authored monograph supplies empirical evidence for the Bayesian brain hypothesis by modeling event-related potentials (ERP) of the human electroencephalogram (EEG) during successive trials in cognitive tasks. The employed observer models are useful to compute probability distributions over observable events and hidden states, depending on which are present in the respective tasks. Bayesian model selection is then used to choose the model which best explains the ERP amplitude fluctuations. Thus, this book constitutes a decisive step towards a better understanding of the neural coding and computing of probabilities following Bayesian rules. The target audience primarily comprises research experts in the field of computational neurosciences, but the book may also be beneficial for graduate students who want to specialize in this field. .
Computational Modeling of Turbulent Swirling Diffusion Flames
Vondál, Jiří
2012-01-01
Schopnost predikovat tepelné toky do stěn v oblasti spalování, konstrukce pecí a procesního průmyslu je velmi důležitá pro návrh těchto zařízení. Je to často klíčový požadavek pro pevnostní výpočty. Cílem této práce je proto získat kvalitní naměřená data na experimentálním zařízení a využít je pro validaci standardně využívaných modelů počítačového modelování turbulentního vířivého difúzního spalování zemního plynu. Experimentální měření bylo provedeno na vodou chlazené spalovací komoře průmy...
Optical computing based on neuronal models
Farhat, Nabil H.
1987-10-01
Ever since the fit between what neural net models can offer (collective, iterative, nonlinear, robust, and fault-tolerant approach to information processing) and the inherent capabilities of optics (parallelism and massive interconnectivity) was first pointed out and the first optical associative memory demonstrated in 1985, work and interest in neuromorphic optical signal processing has been growing steadily. For example, work in optical associative memories is currently being conducted at several academic institutions (e.g., California Institute of Technology, University of Colorado, University of California-San Diego, Stanford University, University of Rochester, and the author's own institution the University of Pennsylvania) and at several industrial and governmental laboratories (e.g., Hughes Research Laboratories - Malibu, the Naval Research Laboratory, and the Jet Propulsion Laboratory). In these efforts, in addition to the vector matrix multiplication with thresholding and feedback scheme utilized in early implementations, an arsenal of sophisticated optical tools such as holographic storage, phase conjugate optics, and wavefront modulation and mixing are being drawn on to realize associative memory functions.
Ruiz, Cristina; Conde, Elena; Torres, Esteban
2005-08-01
We performed a cross-sectional study with three age groups (8, 14, and 17 years) to evaluate developmental differences in stereotyped beliefs about physical attractiveness and the value of this as perceived by the participants. Given the current importance of television in the development of social knowledge, television models were used. The children and adolescents were asked to evaluate, using bipolar open scales, the physical attractiveness, likeableness, generosity, intelligence, fun, and altruism of 12 television models of both sexes, previously selected by judges, as well as the desire to resemble or feel close to the models. Analysis showed developmental differences across age groups both in the concept of physical attractiveness and in stereotyped beliefs about this. As in other areas of social knowledge, the younger children's responses were bipolar, global, and much more stereotyped, while the adolescents introduced subtle distinctions and elaborated their responses. Nevertheless, physical attractiveness appeared a desirable characteristic for all age groups. PMID:16350629
Ruiz, Cristina; Conde, Elena; Torres, Esteban
2005-08-01
We performed a cross-sectional study with three age groups (8, 14, and 17 years) to evaluate developmental differences in stereotyped beliefs about physical attractiveness and the value of this as perceived by the participants. Given the current importance of television in the development of social knowledge, television models were used. The children and adolescents were asked to evaluate, using bipolar open scales, the physical attractiveness, likeableness, generosity, intelligence, fun, and altruism of 12 television models of both sexes, previously selected by judges, as well as the desire to resemble or feel close to the models. Analysis showed developmental differences across age groups both in the concept of physical attractiveness and in stereotyped beliefs about this. As in other areas of social knowledge, the younger children's responses were bipolar, global, and much more stereotyped, while the adolescents introduced subtle distinctions and elaborated their responses. Nevertheless, physical attractiveness appeared a desirable characteristic for all age groups.
Drive for muscularity and disordered eating among French adolescent boys: a sociocultural model.
Rodgers, Rachel F; Ganchou, Camille; Franko, Debra L; Chabrol, Henri
2012-06-01
The pursuit of muscularity is an important body image concern among boys which has been described within sociocultural models of risk for eating disorders. This study explored a sociocultural model of disordered eating in which drive for thinness and pursuit of muscularity were both pathways to disordered eating among French adolescent boys. A sample of 146 adolescents completed a questionnaire assessing drive for thinness, drive for muscularity, media-ideal internalization, appearance comparison, and sociocultural pressure. The model was a good fit to the data and both drive for thinness and the pursuit of muscularity were related to disordered eating. Furthermore, internalization and appearance comparison mediated the relationships between pressure to increase muscle and both drive for muscularity and drive for thinness. Longitudinal research could help clarify the role of the pursuit of muscularity in the development of disordered eating and extreme body shape changing behaviors. PMID:22494958
Basic definitions for discrete modeling of computer worms epidemics
Directory of Open Access Journals (Sweden)
P. Guevara
2015-04-01
Full Text Available The information technologies have evolved in such a way that communication between computers or hosts has become common, so much that the worldwide organization (governments and corporations depends on it; what could happen if these computers stop working for a long time is catastrophic. Unfortunately, networks are attacked by malware such as viruses and worms that could collapse the system. This has served as motivation for the formal study of computer worms and epidemics to develop strategies for prevention and protection; this is why in this paper, before analyzing epidemiological models, a set of formal definitions based on set theory and functions is proposed for describing 21 concepts used in the study of worms. These definitions provide a basis for future qualitative research on the behavior of computer worms, and quantitative for the study of their epidemiological models.
Integrated Multiscale Modeling of Molecular Computing Devices
Energy Technology Data Exchange (ETDEWEB)
Weinan E
2012-03-29
The main bottleneck in modeling transport in molecular devices is to develop the correct formulation of the problem and efficient algorithms for analyzing the electronic structure and dynamics using, for example, the time-dependent density functional theory. We have divided this task into several steps. The first step is to developing the right mathematical formulation and numerical algorithms for analyzing the electronic structure using density functional theory. The second step is to study time-dependent density functional theory, particularly the far-field boundary conditions. The third step is to study electronic transport in molecular devices. We are now at the end of the first step. Under DOE support, we have made subtantial progress in developing linear scaling and sub-linear scaling algorithms for electronic structure analysis. Although there has been a huge amount of effort in the past on developing linear scaling algorithms, most of the algorithms developed suffer from the lack of robustness and controllable accuracy. We have made the following progress: (1) We have analyzed thoroughly the localization properties of the wave-functions. We have developed a clear understanding of the physical as well as mathematical origin of the decay properties. One important conclusion is that even for metals, one can choose wavefunctions that decay faster than any algebraic power. (2) We have developed algorithms that make use of these localization properties. Our algorithms are based on non-orthogonal formulations of the density functional theory. Our key contribution is to add a localization step into the algorithm. The addition of this localization step makes the algorithm quite robust and much more accurate. Moreover, we can control the accuracy of these algorithms by changing the numerical parameters. (3) We have considerably improved the Fermi operator expansion (FOE) approach. Through pole expansion, we have developed the optimal scaling FOE algorithm.
Experiments, Computations and Models for Probabilistic HCF Design
Sandberg, Daniel
2016-01-01
High Cycle Fatigue (HCF) failure is a common failure type for many mechanical components. Traditional HCF design is based on the deterministic safety factor approach, typically used in conjunction with the point stress method. A current development is to explicitly model the uncertainty of the design set-up, and compute the probability of failure, pf. If pf can be computed in an appropriate way, the contributions to fatigue can be identified and managed. Probabilistic design gives improved co...
Inferring brain-computational mechanisms with models of activity measurements
Kriegeskorte, Nikolaus; Diedrichsen, Jörn
2016-01-01
High-resolution functional imaging is providing increasingly rich measurements of brain activity in animals and humans. A major challenge is to leverage such data to gain insight into the brain's computational mechanisms. The first step is to define candidate brain-computational models (BCMs) that can perform the behavioural task in question. We would then like to infer, which of the candidate BCMs best accounts for measured brain-activity data. Here we describe a method that complements each...
Phase Computations and Phase Models for Discrete Molecular Oscillators.
Demir, Alper; Şuvak, Önder
2012-01-01
RESEARCH Open Access Phase computations and phase models for discrete molecular oscillators Onder Suvak* and Alper Demir Abstract Background: Biochemical oscillators perform crucial functions in cells, e.g., they set up circadian clocks. The dynamical behavior of oscillators is best described and analyzed in terms of the scalar quantity, phase. A rigorous and useful definition for phase is based on the so-called isochrons of oscillators. Phase computation techniques for ...
Special Issue: Big data and predictive computational modeling
Koutsourelakis, P. S.; Zabaras, N.; Girolami, M.
2016-09-01
The motivation for this special issue stems from the symposium on "Big Data and Predictive Computational Modeling" that took place at the Institute for Advanced Study, Technical University of Munich, during May 18-21, 2015. With a mindset firmly grounded in computational discovery, but a polychromatic set of viewpoints, several leading scientists, from physics and chemistry, biology, engineering, applied mathematics, scientific computing, neuroscience, statistics and machine learning, engaged in discussions and exchanged ideas for four days. This special issue contains a subset of the presentations. Video and slides of all the presentations are available on the TUM-IAS website http://www.tum-ias.de/bigdata2015/.
Methodology for characterizing modeling and discretization uncertainties in computational simulation
Energy Technology Data Exchange (ETDEWEB)
ALVIN,KENNETH F.; OBERKAMPF,WILLIAM L.; RUTHERFORD,BRIAN M.; DIEGERT,KATHLEEN V.
2000-03-01
This research effort focuses on methodology for quantifying the effects of model uncertainty and discretization error on computational modeling and simulation. The work is directed towards developing methodologies which treat model form assumptions within an overall framework for uncertainty quantification, for the purpose of developing estimates of total prediction uncertainty. The present effort consists of work in three areas: framework development for sources of uncertainty and error in the modeling and simulation process which impact model structure; model uncertainty assessment and propagation through Bayesian inference methods; and discretization error estimation within the context of non-deterministic analysis.
Hybrid Model Based Testing Tool Architecture for Exascale Computing System
Directory of Open Access Journals (Sweden)
Muhammad Usman Ashraf
2015-09-01
Full Text Available Exascale computing refers to a computing system which is capable to at least one exaflop in next couple of years. Many new programming models, architectures and algorithms have been introduced to attain the objective for exascale computing system. The primary objective is to enhance the system performance. In modern/super computers, GPU is being used to attain the high computing performance. However, it’s the objective of proposed technologies and programming models is almost same to make the GPU more powerful. But these technologies are still facing the number of challenges including parallelism, scale and complexity and also many more that must be fixed to achieve make computing system more powerful and efficient. In this paper, we have present a testing tool architecture for a parallel programming approach using two programming models as CUDA and OpenMP. Both CUDA and OpenMP could be used to program shared memory and GPU cores. The object of this architecture is to identify the static errors in the program that occurred during writing the code and cause absence of parallelism. Our architecture enforces the developers to write the feasible code through we can avoid from the essential errors in the program and run successfully.
DEFF Research Database (Denmark)
Rasmussen, Mette; Meilstrup, Charlotte Riebeling; Bendtsen, Pernille;
2015-01-01
communication are associated with young people's social relations. METHODS: Cross-sectional questionnaire survey in 13 schools in the city of Aarhus, Denmark, in 2009. Response rate 89 %, n = 2,100 students in grades 5, 7, and 9. Independent variables were perceived problems related to computer gaming...... and Internet use, respectively. Outcomes were measures of structural (number of days/week with friends, number of friends) and functional (confidence in others, being bullied, bullying others) dimensions of student's social relations. RESULTS: Perception of problems related to computer gaming were associated...... with almost all aspects of poor social relations among boys. Among girls, an association was only seen for bullying. For both boys and girls, perceived problems related to Internet use were associated with bullying only. CONCLUSIONS: Although the study is cross-sectional, the findings suggest that computer...
Marino, Claudia; Vieno, Alessio; Pastore, Massimiliano; Albery, Ian P; Frings, Daniel; Spada, Marcantonio M
2016-12-01
Facebook is the most popular social networking site in the world providing the opportunity to maintain and/or establish relationships, to share media contents and experiences with friends, and to easily communicate with them. Despite the resources and the innovative social features offered by Facebook research has emerged indicating that its use may become problematic, with negative consequences on personal psycho-social well-being, especially among adolescents and young adults. The main aim of this study was to examine the unique contribution of personality traits and social influence processes (i.e. subjective norms, group norms, and social identity) to perceived frequency of Facebook Use and Problematic Facebook Use in a sample of adolescents. A total of 968 Italian adolescents participated in the study. Structural equation modeling showed that emotional stability, extraversion, conscientiousness and norms directly predicted Problematic Facebook Use, whereas gender, group norms and social identity predicted perceived frequency of Facebook use. In conclusion, both personal and social variables appear to explain perceived frequency of Facebook use and Problematic Facebook Use among adolescents, and should be taken into account by researchers and educational practitioners. PMID:27423098
Marino, Claudia; Vieno, Alessio; Pastore, Massimiliano; Albery, Ian P; Frings, Daniel; Spada, Marcantonio M
2016-12-01
Facebook is the most popular social networking site in the world providing the opportunity to maintain and/or establish relationships, to share media contents and experiences with friends, and to easily communicate with them. Despite the resources and the innovative social features offered by Facebook research has emerged indicating that its use may become problematic, with negative consequences on personal psycho-social well-being, especially among adolescents and young adults. The main aim of this study was to examine the unique contribution of personality traits and social influence processes (i.e. subjective norms, group norms, and social identity) to perceived frequency of Facebook Use and Problematic Facebook Use in a sample of adolescents. A total of 968 Italian adolescents participated in the study. Structural equation modeling showed that emotional stability, extraversion, conscientiousness and norms directly predicted Problematic Facebook Use, whereas gender, group norms and social identity predicted perceived frequency of Facebook use. In conclusion, both personal and social variables appear to explain perceived frequency of Facebook use and Problematic Facebook Use among adolescents, and should be taken into account by researchers and educational practitioners.
Soft Tissue Biomechanical Modeling for Computer Assisted Surgery
2012-01-01
This volume focuses on the biomechanical modeling of biological tissues in the context of Computer Assisted Surgery (CAS). More specifically, deformable soft tissues are addressed since they are the subject of the most recent developments in this field. The pioneering works on this CAS topic date from the 1980's, with applications in orthopaedics and biomechanical models of bones. More recently, however, biomechanical models of soft tissues have been proposed since most of the human body is made of soft organs that can be deformed by the surgical gesture. Such models are much more complicated to handle since the tissues can be subject to large deformations (non-linear geometrical framework) as well as complex stress/strain relationships (non-linear mechanical framework). Part 1 of the volume presents biomechanical models that have been developed in a CAS context and used during surgery. This is particularly new since most of the soft tissues models already proposed concern Computer Assisted Planning, with ...
Importance of Computer Model Validation in Pyroprocessing Technology Development
International Nuclear Information System (INIS)
In this research, we developed a plan for experimental validation of one of the computer models developed for ER process modeling, i. e., the ERAD code. Several candidate surrogate materials are selected for the experiment considering the chemical and physical properties. Molten salt-based pyroprocessing technology is being examined internationally as an alternative to treat spent nuclear fuel over aqueous technology. The central process in pyroprocessing is electrorefining(ER) which separates uranium from transuranic elements and fission products present in spent nuclear fuel. ER is a widely used process in the minerals industry to purify impure metals. Studies of ER by using actual spent nuclear fuel materials are problematic for both technical and political reasons. Therefore, the initial effort for ER process optimization is made by using computer models. A number of models have been developed for this purpose. But as validation of these models is incomplete and often times problematic, the simulation results from these models are inherently uncertain