Predicting the Mechanical Properties of Carbon-Based Materials Using Molecular Dynamics

The development of innovative carbon-based materials can be greatly facilitated by molecular modeling techniques. Although molecular modeling has been used extensively to predict elastic properties of materials, modeling of more complex phenomenon such as fracture has only recently been possible with the development of new force fields such as ReaxFF, which is used in this work. It is not fully understood what molecular modeling parameters such as thermostat type, thermostat coupling, time step, system size, and strain rate are required for accurate modeling of fracture. Selection of modeling parameters to model fracture can be difficult and non-intuitive compared to modeling elastic properties using traditional force fields, and the errors generated by incorrect parameters may be non-obvious. These molecular modeling parameters are systematically investigated and their effects on the fracture of well-known carbon materials are analyzed. It is determined that for coupling coefficients of 250 fs and greater do not result in substantial differences in the stress-strain response of the materials using any thermostat type. A time step of 0.5 fs of smaller is required for accurate results. Strain rates greater than 2.2 ns-1 are sufficient to obtain repeatable results with slower strain rates for the materials studied. The results of this study indicate that further refinement of the Chenoweth parameter set is required to accurately predict the mechanical response of carbon-based systems. The ReaxFF has been used extensively to model systems in which bond breaking and formation occur. In particular ReaxFF has been used to model reactions of small molecules. Some elastic and fracture properties have been successfully modeled using ReaxFF in materials such as silicon and some metals. However, it is not clear if current parameterizations for ReaxFF are able to accurately reproduce the elastic and fracture properties of carbon materials. The stress-strain response of a new ReaxFF parameterization is compared to the previous parameterization and density functional theory results for well-known carbon materials. The new ReaxFF parameterization makes xv substantial improvements to the predicted mechanical response of carbon materials, and is found to be suitable for modeling the mechanical response of carbon materials. Finally, a new material composed of carbon nanotubes within an amorphous carbon (AC) matrix is modeled using the ReaxFF. Various parameters that may be experimentally controlled are investigated such as nanotube bundling, comparing multi-walled nanotube with single-walled nanotubes, and degree of functionalization of the nanotubes. Elastic and fracture properties are investigated for the composite systems and compared to results of pure-nanotube and pure-AC models. It is found that the arrangement of the nanotubes and degree of crosslinking may substantially affect the properties of the systems, particularly in the transverse directions.

Constructing a user experience user experience-based mobile learning environment

Mobile learning, in the past defined as learning with mobile devices, now refers to any type of learning-on-the-go or learning that takes advantage of mobile technologies. This new definition shifted its focus from the mobility of technology to the mobility of the learner (O'Malley and Stanton 2002; Sharples, Arnedillo-Sanchez et al. 2009). Placing emphasis on the mobile learner’s perspective requires studying “how the mobility of learners augmented by personal and public technology can contribute to the process of gaining new knowledge, skills, and experience” (Sharples, Arnedillo-Sanchez et al. 2009). The demands of an increasingly knowledge based society and the advances in mobile phone technology are combining to spur the growth of mobile learning. Around the world, mobile learning is predicted to be the future of online learning, and is slowly entering the mainstream education. However, for mobile learning to attain its full potential, it is essential to develop more advanced technologies that are tailored to the needs of this new learning environment. A research field that allows putting the development of such technologies onto a solid basis is user experience design, which addresses how to improve usability and therefore user acceptance of a system. Although there is no consensus definition of user experience, simply stated it focuses on how a person feels about using a product, system or service. It is generally agreed that user experience adds subjective attributes and social aspects to a space that has previously concerned itself mainly with ease-of-use. In addition, it can include users’ perceptions of usability and system efficiency. Recent advances in mobile and ubiquitous computing technologies further underline the importance of human-computer interaction and user experience (feelings, motivations, and values) with a system. Today, there are plenty of reports on the limitations of mobile technologies for learning (e.g., small screen size, slow connection), but there is a lack of research on user experience with mobile technologies. This dissertation will fill in this gap by a new approach in building a user experience-based mobile learning environment. The optimized user experience we suggest integrates three priorities, namely a) content, by improving the quality of delivered learning materials, b) the teaching and learning process, by enabling live and synchronous learning, and c) the learners themselves, by enabling a timely detection of their emotional state during mobile learning. In detail, the contributions of this thesis are as follows: • A video codec optimized for screencast videos which achieves an unprecedented compression rate while maintaining a very high video quality, and a novel UI layout for video lectures, which together enable truly mobile access to live lectures. • A new approach in HTTP-based multimedia delivery that exploits the characteristics of live lectures in a mobile context and enables a significantly improved user experience for mobile live lectures. • A non-invasive affective learning model based on multi-modal emotion detection with very high recognition rates, which enables real-time emotion detection and subsequent adaption of the learning environment on mobile devices. The technology resulting from the research presented in this thesis is in daily use at the School of Continuing Education of Shanghai Jiaotong University (SOCE), a blended-learning institution with 35.000 students.

Semantic Methods for Intelligent Distributed Design Environments

Continuous advancements in technology have led to increasingly comprehensive and distributed product development processes while in pursuit of improved products at reduced costs. Information associated with these products is ever changing, and structured frameworks have become integral to managing such fluid information. Ontologies and the Semantic Web have emerged as key alternatives for capturing product knowledge in both a human-readable and computable manner. The primary and conclusive focus of this research is to characterize relationships formed within methodically developed distributed design knowledge frameworks to ultimately provide a pervasive real-time awareness in distributed design processes. Utilizing formal logics in the form of the Semantic Web’s OWL and SWRL, causal relationships are expressed to guide and facilitate knowledge acquisition as well as identify contradictions between knowledge in a knowledge base. To improve the efficiency during both the development and operational phases of these “intelligent” frameworks, a semantic relatedness algorithm is designed specifically to identify and rank underlying relationships within product development processes. After reviewing several semantic relatedness measures, three techniques, including a novel meronomic technique, are combined to create AIERO, the Algorithm for Identifying Engineering Relationships in Ontologies. In determining its applicability and accuracy, AIERO was applied to three separate, independently developed ontologies. The results indicate AIERO is capable of consistently returning relatedness values one would intuitively expect. To assess the effectiveness of AIERO in exposing underlying causal relationships across product development platforms, a case study involving the development of an industry-inspired printed circuit board (PCB) is presented. After instantiating the PCB knowledge base and developing an initial set of rules, FIDOE, the Framework for Intelligent Distributed Ontologies in Engineering, was employed to identify additional causal relationships through extensional relatedness measurements. In a conclusive PCB redesign, the resulting “intelligent” framework demonstrates its ability to pass values between instances, identify inconsistencies amongst instantiated knowledge, and identify conflicting values within product development frameworks. The results highlight how the introduced semantic methods can enhance the current knowledge acquisition, knowledge management, and knowledge validation capabilities of traditional knowledge bases.

Explaining Variations in Client Extra Costs between Software Projects Offshored to India

Gaining economic benefits from substantially lower labor costs has been reported as a major reason for offshoring labor-intensive information systems services to low-wage countries. However, if wage differences are so high, why is there such a high level of variation in the economic success between offshored IS projects? This study argues that offshore outsourcing involves a number of extra costs for the ^his paper was recommended for acceptance by Associate Guest Editor Erran Carmel. client organization that account for the economic failure of offshore projects. The objective is to disaggregate these extra costs into their constituent parts and to explain why they differ between offshored software projects. The focus is on software development and maintenance projects that are offshored to Indian vendors. A theoretical framework is developed a priori based on transaction cost economics (TCE) and the knowledge-based view of the firm, comple mented by factors that acknowledge the specific offshore context The framework is empirically explored using a multiple case study design including six offshored software projects in a large German financial service institution. The results of our analysis indicate that the client incurs post contractual extra costs for four types of activities: (1) re quirements specification and design, (2) knowledge transfer, (3) control, and (4) coordination. In projects that require a high level of client-specific knowledge about idiosyncratic business processes and software systems, these extra costs were found to be substantially higher than in projects where more general knowledge was needed. Notably, these costs most often arose independently from the threat of oppor tunistic behavior, challenging the predominant TCE logic of market failure. Rather, the client extra costs were parti cularly high in client-specific projects because the effort for managing the consequences of the knowledge asymmetries between client and vendor was particularly high in these projects. Prior experiences of the vendor with related client projects were found to reduce the level of extra costs but could not fully offset the increase in extra costs in highly client-specific projects. Moreover, cultural and geographic distance between client and vendor as well as personnel turnover were found to increase client extra costs. Slight evidence was found, however, that the cost-increasing impact of these factors was also leveraged in projects with a high level of required client-specific knowledge (moderator effect).

A web-based non-intrusive ambient system to measure and classify activities of daily living.

BACKGROUND The number of older adults in the global population is increasing. This demographic shift leads to an increasing prevalence of age-associated disorders, such as Alzheimer's disease and other types of dementia. With the progression of the disease, the risk for institutional care increases, which contrasts with the desire of most patients to stay in their home environment. Despite doctors' and caregivers' awareness of the patient's cognitive status, they are often uncertain about its consequences on activities of daily living (ADL). To provide effective care, they need to know how patients cope with ADL, in particular, the estimation of risks associated with the cognitive decline. The occurrence, performance, and duration of different ADL are important indicators of functional ability. The patient's ability to cope with these activities is traditionally assessed with questionnaires, which has disadvantages (eg, lack of reliability and sensitivity). Several groups have proposed sensor-based systems to recognize and quantify these activities in the patient's home. Combined with Web technology, these systems can inform caregivers about their patients in real-time (e.g., via smartphone). OBJECTIVE We hypothesize that a non-intrusive system, which does not use body-mounted sensors, video-based imaging, and microphone recordings would be better suited for use in dementia patients. Since it does not require patient's attention and compliance, such a system might be well accepted by patients. We present a passive, Web-based, non-intrusive, assistive technology system that recognizes and classifies ADL. METHODS The components of this novel assistive technology system were wireless sensors distributed in every room of the participant's home and a central computer unit (CCU). The environmental data were acquired for 20 days (per participant) and then stored and processed on the CCU. In consultation with medical experts, eight ADL were classified. RESULTS In this study, 10 healthy participants (6 women, 4 men; mean age 48.8 years; SD 20.0 years; age range 28-79 years) were included. For explorative purposes, one female Alzheimer patient (Montreal Cognitive Assessment score=23, Timed Up and Go=19.8 seconds, Trail Making Test A=84.3 seconds, Trail Making Test B=146 seconds) was measured in parallel with the healthy subjects. In total, 1317 ADL were performed by the participants, 1211 ADL were classified correctly, and 106 ADL were missed. This led to an overall sensitivity of 91.27% and a specificity of 92.52%. Each subject performed an average of 134.8 ADL (SD 75). CONCLUSIONS The non-intrusive wireless sensor system can acquire environmental data essential for the classification of activities of daily living. By analyzing retrieved data, it is possible to distinguish and assign data patterns to subjects' specific activities and to identify eight different activities in daily living. The Web-based technology allows the system to improve care and provides valuable information about the patient in real-time.

Capability of a space-based space surveillance system to detect and track objects in GEO, MEO and LEO orbits

In this paper we present the results from the coverage and the orbit determination accuracy simulations performed within the recently completed ESA study “Assessment Study for Space Based Space Surveillance (SBSS) Demonstration System” (Airbus Defence and Space consortium). This study consisted in investigating the capability of a space based optical sensor (SBSS) orbiting in low Earth orbit (LEO) to detect and track objects in GEO (geosynchronous orbit), MEO (medium Earth orbit) and LEO and to determinate and improve initial orbits from such observations. Space based systems may achieve better observation conditions than ground based sensors in terms of astrometric accuracy, detection coverage, and timeliness. The primary observation mode of the proposed SBSS demonstrator is GEO surveillance, i.e. the systematic search and detection of unknown and known objects. GEO orbits are specific and unique orbits from dynamical point of view. A space-based sensor may scan the whole GEO ring within one sidereal day if the orbit and pointing directions are chosen properly. For an efficient survey, our goal was to develop a leak-proof GEO fence strategy. Collaterally, we show that also MEO, LEO and other (GTO,Molniya, etc.) objects would be possible to observe by the system and for a considerable number of LEO objects to down to size of 1 cm we can obtain meaningful statistical data for improvement and validation of space debris environment models

DETERMINING THE GENOTYPE-PHENOTYPE CONNECTION IN SYNTHETIC INDUCIBLE GENE EXPRESSION SYSTEMS

Introduction Gene expression is an important process whereby the genotype controls an individual cell’s phenotype. However, even genetically identical cells display a variety of phenotypes, which may be attributed to differences in their environment. Yet, even after controlling for these two factors, individual phenotypes still diverge due to noisy gene expression. Synthetic gene expression systems allow investigators to isolate, control, and measure the effects of noise on cell phenotypes. I used mathematical and computational methods to design, study, and predict the behavior of synthetic gene expression systems in S. cerevisiae, which were affected by noise. Methods I created probabilistic biochemical reaction models from known behaviors of the tetR and rtTA genes, gene products, and their gene architectures. I then simplified these models to account for essential behaviors of gene expression systems. Finally, I used these models to predict behaviors of modified gene expression systems, which were experimentally verified. Results Cell growth, which is often ignored when formulating chemical kinetics models, was essential for understanding gene expression behavior. Models incorporating growth effects were used to explain unexpected reductions in gene expression noise, design a set of gene expression systems with “linear” dose-responses, and quantify the speed with which cells explored their fitness landscapes due to noisy gene expression. Conclusions Models incorporating noisy gene expression and cell division were necessary to design, understand, and predict the behaviors of synthetic gene expression systems. The methods and models developed here will allow investigators to more efficiently design new gene expression systems, and infer gene expression properties of TetR based systems.

La economía del conocimiento : perspectivas urbano - regionales

El conocimiento y su aplicación en la economía, ha sido siempre un factor importante del desarrollo socio-económico. El conocimiento toma relevancia en la economía contemporánea al invertirse la jerarquización de los factores del desarrollo, cobrando mayor importancia los factores intangibles, como el conocimiento, el cual se convierte en el recurso fundamental para los procesos productivos. En este contexto, surgieron los estudios relacionados con la Economía Regional del Conocimiento (ERC) así como los estudios relativos al Desarrollo basado en el Conocimiento (DBC). Ambas perspectivas teóricas han establecido indicadores para explicar el fenómeno de la economía del conocimiento desde su base territorial, sea a nivel regional (ERC) o desde la ciudad (DBC). A manera exploratoria consideramos que los indicadores de los sistemas regionales de innovación pueden complementarse con los indicadores del desarrollo basado en el conocimiento, sobre todo por la dimensión meta-cultural a la que hacen referencia estos estudios.

Modelo para la toma de decisiones sobre los contenidos curriculares de la Organización del Conocimiento en programas académicos de Bibliotecología, Documentación o Ciencia de la Información

Se presenta un modelo para decidir los contenidos curriculares de la Organización del Conocimiento en carreras de Bibliotecología, Documentación y Ciencia de la Información, orientado principalmente al Mercosur. Para el diseño del modelo se tuvieron en cuenta los contenidos mínimos recomendados por los encuentros de directores y docentes de escuelas de Bibliotecología del Mercosur, la llamada corriente de ISKO y los aportes de distintos autores relacionados con ambas fuentes. El modelo consta de tres categorías primarias: fundamentos, aplicaciones y ética de la Organización del Conocimiento. Los fundamentos se consideran desde un abordaje multidimensional. Las aplicaciones se dividen en tres categorías primarias: a) construcción de sistemas de organización del conocimiento, b) descripción de contenido y c) gestión de calidad de la Organización del Conocimiento. La ética también se divide en tres categorías secundarias: compromiso ético, valores éticos y problemas éticos. El modelo debe entenderse como un molde vacío que necesita llenarse con los contenidos que decida cada carrera o cada espacio curricular y se espera que facilite la evaluación, actualización y comparación de esos contenidos. Tiene la limitación de basarse en las recomendaciones del Mercosur y la corriente de ISKO, que no son aceptadas por todos los especialistas

La gestión del conocimiento en las Bibliotecas Universitarias : ¿El qué, cómo y para qué?

El presente artículo tiene como propósito proponer la incorporación de la teoría administrativa denominada Gestión del Conocimiento (GC), en Bibliotecas Universitarias (BU). ¿El qué, el cómo y el para qué? Representa un reto de gestión que conlleva a la implementación de diversas estrategias para el cambio y la innovación (ECI). Hipotéticamente, el diseño de estrategias de gestión posibilita que la BU en los escenarios competitivos de la sociedad de conocimiento y el tercer entorno desarrolle nuevas competencias y directrices para el aprovechamiento de sus diversos recursos con eficiencia y logren alcanzar sus objetivos con eficacia. La innovación es otra de las variables que posibilita la transformación de los servicios que son ofertados a los usuarios, también denominados "socios estratégicos", bajo la visión de creatividad, sustentabilidad y bienestar

La garantía cultural como justificación en sistemas de organización de conocimiento : Aproximación crítica

Se realiza un análisis exploratorio del concepto de "garantía cultural", con el objetivo de caracterizar áreas futuras de investigación en torno al mismo. En primera instancia se analiza la noción genérica de 'garantía', tal como ha sido considerada en la Organización del Conocimiento. Se reseñan diversos tipos de garantías propuestas para legitimar la inclusión de terminología en sistemas de organización del conocimiento. Se cumple un análisis crítico del concepto de "cultura" y la manera en que distintas concepciones antropológicas, sociológicas y políticas confluyen en su construcción epistemológica. Se revisa y se problematiza el tratamiento de la garantía cultural en la literatura del área. Se valora su aporte en la construcción de identidades culturales, a través de elementos de diferenciación de la interpretación y la vivencia de la realidad. En particular se desarrolla la relación entre garantía cultural y cultura local. Se pondera la inserción del factor ético a través de la garantía cultura, en el desarrollo de esquemas de clasificación y en los procesos de clasificación e indización. Entre otras conclusiones, se establece la necesidad de explorar con mayor detenimiento las alternativas metodológicas que puedan sustentarse en esta concepción integradora y democratizadora en el ámbito de la Organización del Conocimiento

Modelo para la toma de decisiones sobre los contenidos curriculares de la Organización del Conocimiento en programas académicos de Bibliotecología, Documentación o Ciencia de la Información

Se presenta un modelo para decidir los contenidos curriculares de la Organización del Conocimiento en carreras de Bibliotecología, Documentación y Ciencia de la Información, orientado principalmente al Mercosur. Para el diseño del modelo se tuvieron en cuenta los contenidos mínimos recomendados por los encuentros de directores y docentes de escuelas de Bibliotecología del Mercosur, la llamada corriente de ISKO y los aportes de distintos autores relacionados con ambas fuentes. El modelo consta de tres categorías primarias: fundamentos, aplicaciones y ética de la Organización del Conocimiento. Los fundamentos se consideran desde un abordaje multidimensional. Las aplicaciones se dividen en tres categorías primarias: a) construcción de sistemas de organización del conocimiento, b) descripción de contenido y c) gestión de calidad de la Organización del Conocimiento. La ética también se divide en tres categorías secundarias: compromiso ético, valores éticos y problemas éticos. El modelo debe entenderse como un molde vacío que necesita llenarse con los contenidos que decida cada carrera o cada espacio curricular y se espera que facilite la evaluación, actualización y comparación de esos contenidos. Tiene la limitación de basarse en las recomendaciones del Mercosur y la corriente de ISKO, que no son aceptadas por todos los especialistas

La gestión del conocimiento en las Bibliotecas Universitarias : ¿El qué, cómo y para qué?

El presente artículo tiene como propósito proponer la incorporación de la teoría administrativa denominada Gestión del Conocimiento (GC), en Bibliotecas Universitarias (BU). ¿El qué, el cómo y el para qué? Representa un reto de gestión que conlleva a la implementación de diversas estrategias para el cambio y la innovación (ECI). Hipotéticamente, el diseño de estrategias de gestión posibilita que la BU en los escenarios competitivos de la sociedad de conocimiento y el tercer entorno desarrolle nuevas competencias y directrices para el aprovechamiento de sus diversos recursos con eficiencia y logren alcanzar sus objetivos con eficacia. La innovación es otra de las variables que posibilita la transformación de los servicios que son ofertados a los usuarios, también denominados "socios estratégicos", bajo la visión de creatividad, sustentabilidad y bienestar

La garantía cultural como justificación en sistemas de organización de conocimiento : Aproximación crítica

Se realiza un análisis exploratorio del concepto de "garantía cultural", con el objetivo de caracterizar áreas futuras de investigación en torno al mismo. En primera instancia se analiza la noción genérica de 'garantía', tal como ha sido considerada en la Organización del Conocimiento. Se reseñan diversos tipos de garantías propuestas para legitimar la inclusión de terminología en sistemas de organización del conocimiento. Se cumple un análisis crítico del concepto de "cultura" y la manera en que distintas concepciones antropológicas, sociológicas y políticas confluyen en su construcción epistemológica. Se revisa y se problematiza el tratamiento de la garantía cultural en la literatura del área. Se valora su aporte en la construcción de identidades culturales, a través de elementos de diferenciación de la interpretación y la vivencia de la realidad. En particular se desarrolla la relación entre garantía cultural y cultura local. Se pondera la inserción del factor ético a través de la garantía cultura, en el desarrollo de esquemas de clasificación y en los procesos de clasificación e indización. Entre otras conclusiones, se establece la necesidad de explorar con mayor detenimiento las alternativas metodológicas que puedan sustentarse en esta concepción integradora y democratizadora en el ámbito de la Organización del Conocimiento