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Mengintegrasikan Model Kesiapan Dan Kegunaan Untuk Menilai Penggunaan Sistem Informasi
Get PDFEC00201823069, 7 Agustus 201
Development of System Continuance Models for Assessing among Local E-Government in Indonesia
Get PDFThis study reports how to combine technology acceptance and use models based on expectations and confirmations in the information system success model to objectively assess the continuance of local e- government based on the organizational perspective and perspective of users in Indonesia. The developed model is arranged in 11 variables and 48 indicators. Pathways of influence between variables are presented by 16 links. However, this study does have some limitations. With regard to the level of use, there is no fully mandatory use of the system, and not all UTAUT2 variables and the possibility of a moderator are integrated with the model. Other studies used various assumptions, methods, and different understandings can present different propositions. In addition, limitations can help to further study, especially the validity of the proposed model. Future research can explore additional expansion variables and moderators, so that in the new model between variables can be made more explicit relationship
PENINGKATAN KEMAMPUAN KOMUNIKASI MATEMATIS DENGAN MENGGUNAKAN MODEL PEMBELAJARAN PAIR CHECKS
No full textPenelitian ini dilatarbelakangi oleh rendahnya kemampuan komunikasi matematis siswa. Salah satu upaya untuk meningkatkan kemampuan komunikasi matematis siswa yaitu dengan menggunakan model pembelajaran pair checks. Secara umum tujuan penelitian ini yaitu untuk mengetahui peningkatan kemampuan komunikasi matematis siswa yang pembelajarannya menggunakan model pair checks dibandingkan dengan siswa yang pembelajarannya menggunakan model konvensional, serta untuk mengetahui sikap siswa terhadap pembelajaran matematika dengan menggunakan model pair checks. Penelitian ini menggunakan metode kuasi eksperimen terhadap siswa kelas VII SMP Negeri 7 Sumedang tes kemampuan komunikasi matematis. Berdasarkan hasil pengolahan data dengan uji pada sebanyak dua kelas, yaitu kelas VII-B dengan jumlah 27 siswa sebagai kelas eksperimen dan taraf signifikansi 5% diperoleh nilai dan nilai dengan demikian kelas VII-E dengan jumlah 29 siswa sebagai kelas kontrol. Instrumen yang digunakan adalah maka ditolak. Artinya peningkatan kemampuan komunikasi matematis siswa yang pembelajarannya menggunakan model pembelajaran pair checks lebih baik dibandingkan dengan siswa yang pembelajarannya menggunakan model pembelajaran konvensional
Experimental study of plasma turbulence in the TCV tokamak
No full textThis thesis presents an experimental investigation of electron density fluctuations in the TCV tokamak, primarily with the tangential phase contrast imaging (TPCI) diagnostic. The focus is to study the small-scale broadband turbulence in the plasma, which has long been believed to be the primary cause of anomalous transport, one of the most important issues for magnetic confinement fusion research. Nonlinear interactions within the turbulence can drive zonal flows, which in turn modulate and suppress the turbulence; geodesic acoustic modes (GAMs) are associated to zonal flows and easier to detect thanks to their finite frequency. A characterization of the GAMs in TCV with multiple diagnostics constitutes a central part of this work. The study includes spatial profile measurements as well as frequency and wavenumber spectra of turbulence and GAMs in various plasma conditions. The first part of this work is dedicated to investigating the improvement in energy confinement when the triangularity at the edge of the plasma poloidal cross-section changes from positive to negative. Measurements of turbulent density fluctuations show a substantial reduction of the turbulence amplitude, decorrelation time and radial correlation length from positive to negative triangularity. In addition, the turbulence amplitude decreases with the effective collisionality of the plasma in the Trapped Electron Mode (TEM) regime. This result is consistent with the experimental observation of transport reduction in TCV and with nonlinear gyrokinetic simulations. The second part of this thesis is focused on the characterization of the GAMs in TCV. A transition has been observed in the course of a single discharge from a local regime, with frequency varying along the radius according to a theoretically predicted linear dependence on the sound speed, to a radially extended regime, in which the oscillations are at a constant frequency over a large fraction of the minor radius. Gyrokinetic simulations succeed in reproducing the transition. The coupling between the GAM and the broadband turbulence was studied in a density ramp-up using bispectral techniques. The GAM has also been observed and characterized for the first time in the scrape-off layer (SOL), primarily by magnetic probes and Langmuir probes but also by Dalpha emission.SP
Thermal transport in low dimensions
No full textLattice vibrations are the microscopic mechanism responsible for a large, if not dominant, contribution to heat transport in crystalline insulators. These vibrations are described in terms of phonons, collective excitations (or quasiparticles) in the form of waves of atomic displacements inside a crystal. Phonons are traditionally considered to be the quasiparticles responsible for carrying heat through the material. Heat transport is considered as a flux of a phonon gas, diffusing from hot areas (high phonon densities) to cold areas (low phonon densities) in an attempt to reestablish equilibrium, with phonon collisions being the source of heat flux dissipation. However, as dimensionality is reduced, the motion of phonons stimulated by temperature perturbations becomes correlated and this gas-like picture of thermal transport in terms of phonons becomes invalid. In this Thesis, we lay out an interpretation of thermal transport in 2D materials based on the Boltzmann transport equation in the form of collective excitations of phonons. These collective phonon excitations give raise to complex phenomena, such as high thermal conductivities, that are otherwise unexplained. As another example, collective excitations, at variance with conventional diffusive transport, can induce wave-like heat propagation, or second sound. This had been found only in a few exotic materials at cryogenic temperatures, but is present instead routinely in 2D materials at room temperature. The correlated-phonon description of heat transfer can be rationalised by introducing a new collective excitation, called 'relaxon', which is defined as the eigenstate of the collision operator. Whereas only oversimplifying assumptions endow phonons with well defined relaxation times (the average interval of time between collisions), relaxons have always well defined relaxation times and permit an exact description of thermal transport. The complex dynamic of heat transport in 2D is thus greatly simplified and a kinetic gas theory of thermal transport still applies, provided that the gas is not constituted by phonons, but by relaxons. Our work on thermal transport is part of a larger effort, aiming at the creation of a database of numerically computed properties of materials. The high-throughput production of simulated properties is a challenging task, since it necessitates the understanding of a physical model, but it also needs to face a myriad of technicalities and problems that hinder the execution of a large number of calculations. In order to allow the creation of computational materials databases, we developed AiiDA, an open-source automated interactive infrastructure and database for computational science. This platform tackles the problems of creation, management, analysis and sharing of data and simulations, summarized in the pillars of Automation, Data, Environment and Sharing. Automation is achieved by management of remote computational resources and the encoding of workflows, that allows the execution of complex sequences of calculations. The tight coupling between automation and data storage, handled by the platform, enables full reproducibility of the results and a suitable database design allows for efficient data analysis tools. Sharing of scientific knowledge is addressed by providing tools for distribution of data and of the underlying workflows that generated them, creating an ecosystem for computational materials science.THEO
On the Symbiosis of People and Building : The Perfect Slum
No full textControversies continue to exist between architects and the public about what is a good building. High-style modern architecture is often disliked by the public. Moreover, in everyday life people blame the architect for everything they find impractical in a building. The non-operable window is emblematic of this controversy. The kernel of the problem lies in the lack of knowledge about how people relate to their buildings. This thesis investigates the relationship between people and their buildings, a topic that lies on the interface of architecture, psychology, and anthropology. In architecture, many have attempted to create buildings that feel alive, although much of what is built today feels alien to those who inhabit it. Environmental psychology has its focus on perception and meaning, whereas in anthropology, the habitat is often observed in a cultural perspective. This thesis aims at building theory that connects the insights of these disciplines. The importance of the topic lies in the increasing alienation of people from their buildings. Although many architects work on buildings that we can better relate to, alienation and disconnection continue to exist because, to mention one aspect, the built environment is made by more people than only architects. In the multidisciplinary world, improvement of the relationship of people and building would surely benefit from the introduction of a clear focal point and an adequate conceptual framework. From literature, insights were collected that explain the relationship in four perspectives: human aspects, properties of buildings, its relation to society, and abstract systems. Together they form a model that can serve as the focal point. Next, in order to identify what is changing in the relationship, the model was used as research tool in different contexts, ranging from vernacular to modern. Fieldwork research was conducted in traditional habitats, state-of-the-art modern buildings, and settings in between: primitive housing in urban slum or informal settlement. Detailed research methods for the survey of people's interaction with buildings were newly developed in the field and combined with existing sampling and coding techniques. Architects tools like sketches, scale models, and photography were used next to interviews and participatory observation. Results are presented in several reports ranging from slum dwellings to hi-tech. Besides architecture, they describe the practice of everyday life, logic and inconsistencies in building methods, and effects on the people-building relationship. From the findings, we concluded that what happened to the people-building relationship in the transition from vernacular to modern could be described in five trends. These trends explain the current disconnection as well as the difficulties we face in creating live buildings. Thus, together with the focal point, a conceptual framework is created holding the patterns typical of the people-building relationship. This knowledge can be used as both tool and theory by the profession. The research suggests that in order to create a strong people-building relationship, the whole process of building, dwelling, and daily operation must be focused on inclusion of the end-user. Today's technology and regulations favor exclusion and therefore contribute to a built environment that is not humanly sustainable.LC
Hardening induced by radiation damage and helium in structural materials
No full textIrradiation is known to lead to degradation of mechanical properties of materials. Structural materials for nuclear applications can be affected by helium produced by transmutations. The objectives of this work were: (a) to investigate the effects of He on the mechanical properties of steels in different irradiation conditions (neutron spallation source and He-implantation), (b) to study the irradiation-induced hardening effect and the contribution of He on the hardening, (c) to compare the barrier strength of helium bubbles to moving dislocations as well as that of defect clusters and (d) to interpret the individual and combined barrier strengths to the overall hardening contribution. These goals have been reached by performing detailed hardness measurements on F82H ferritic/martensitic (f/m) steel after spallation neutron irradiation to 6.2-20.3 dpa (displacement per atom) at 151-344 °C and to a He-concentration of 465-1825 appm (atomic part per million) as well as after annealing treatments (300 °C/1 h, 400 °C/1 h, 600 °C/1 h and 600 °C/200 h). The annealing treatments were applied to remove the defect clusters stepwise and make the He-bubbles grow. Austenitic steel SS316L and f/m steels F82H and Optifer, helium implanted (0.2 dpa , 1350 appm He) with a 28 MeV He-beam at room temperature and after annealing were used to gain complementary information on the barrier strength of the helium bubbles. A significant increase in hardness following irradiation and implantation was observed: the largest increase in hardening was observed for the specimen with the highest received dose and He concentration. In comparison to the as-irradiated specimens, the hardness values of the annealed specimens were distinctively lower. The annealing demonstrated a continuously decrease with increasing annealing temperature. Detailed transmission electron microscopy (TEM) has been performed on STIP-II irradiated specimens in the as-irradiated condition and after annealing at 600 °C/1 h and 600 °C/200 h as well as on He-implanted specimens in their annealed condition. These investigations provided quantitative information on size distribution and density of defect clusters and helium bubbles as a function of irradiation dose, helium concentration and irradiation temperature. The helium bubbles were found to be weaker obstacles to dislocation than the defect clusters whereas their contribution to irradiation hardening cannot be neglected owing to their high density. Scanning transmission electron microscopy in combination with electron energy loss spectroscopy was performed on selected specimens. These investigations provided quantitative information on the helium number density
Dynamic control of light transmission through multimode fibers
No full textIn the present thesis we demonstrate how under the appropriate dynamic control of light propagation, multimode fibers can be transformed into deterministic optical elements that along with their ultrathin size, large number of degrees of freedom and high Numerical Aperture, can be used as a new platform to fabricate miniature optical elements with applications in minimally invasive endoscopy, phototherapy and photoexcitation deep inside biological tissue. Firstly we demonstrate that using Digital Phase Conjugation, light can be focused into a diffraction limited spot at the output of a multimode fiber. The handling of the data in the digital domain, allows us to dynamically raster scan the focused spot across the whole fiber facet thus enabling the use of the system in scanning fluorescent imaging. We exploit the focusing and scanning capabilities of the system, along with the very small diameter of multimode fibers to demonstrate a rigid ultrathin high resolution endoscopic modality and perform fluorescence imaging of stained neuronal cells. The high quality of the obtained images allows the use of the system as a minimally invasive endoscope for cellular diagnosis via direct tissue penetration. Moreover, we extend the capabilities of the demonstrated device by performing imaging based on the optical absorption properties of samples via the photoacoustic effect. The use of a multimode fiber as the optical excitation part can enable the generation of new photoacoustic endoscopic modalities that can deliver optical resolution images deeper than the ballistic range of light propagation in tissue. Furthermore, we enhance the imaging capabilities of multimode fiber based imaging system by exploiting the properties of a highly scattering medium. The synergetic use of a multimode fiber and a scattering medium provides the imaging system with a higher number of degrees of freedom and enables the coupling of higher order to lower modes. Finally, aiming towards the fabrication of semi-flexible multimode fiber based endoscopic modalities, we demonstrate a system that is capable of overcoming the dependence of the modal mixing to the geometrical configuration of the fiber, to continuously focus through a bending multimode fiber. Overall, the presented results verify that the ultra-thin diameter of multimode fibers, in conjunction with the dynamic control of light transmission through them, allow us to envision multimode fibers as a new family of miniature versatile optical elements with multiple applications in biomedical optics.L
Turbulent regimes in the tokamak scrape-off layer
No full textThe tokamak scrape-off layer (SOL) is the plasma region characterized by open field lines that start and end on the vessel walls. The plasma dynamics in the SOL plays a crucial role in determining the overall performance of a tokamak, since it controls the plasma-wall interactions, being responsible of exhausting the tokamak power, it regulates the overall plasma confinement, and it governs the plasma refueling and the removal of fusion ashes. Scrape-off layer physics is intrinsically non-linear and characterized by phenomena that occur on a wide range of spatio-temporal scales. Free energy sources drive a number of unstable modes that develop into turbulence and lead to transport of particles and heat across the magnetic field lines. Depending on the driving instability, different SOL turbulent regimes can be identified. As the SOL turbulent regimes determine the plasma confinement properties and the SOL width (and, consequently, the power flux on the vessel wall, for example), it is of crucial importance to understand which turbulent regimes are active in the SOL, under which conditions they develop, and which are the main properties of the associated turbulent transport. In the present thesis we define the SOL turbulent regimes, and we provide a framework to identify them, given the operational SOL parameters. Our study is based on the drift-reduced Braginskii equations and it is focused on a limited tokamak SOL configuration. We first describe the main SOL linear instabilities, such as the inertial and resistive branches of the drift waves, the resistive, inertial and ideal branches of the ballooning modes, and the ion temperature gradient mode. Then, we find the SOL turbulent regimes depending on the instability driving turbulent transport, assuming that turbulence saturates when the radial gradient associated to the pressure fluctuations is comparable to the equilibrium one. Our methodology for the turbulent regime identification is supported by the analysis of non-linear turbulence simulations performed with the GBS code, a flux-driven, 3D code that solves the drift-reduced Braginskii equations without separation between background and fluctuations. We find that drift waves drive transport at low resistivity and negative magnetic shear, while ballooning modes dominate at high resistivity and positive magnetic shear. The ion temperature gradient instability plays a negligible role in the SOL dynamics, since the ion temperature gradient is generally below the threshold necessary for the development of this instabilityCRPPSP
Analyse, synthèse et création d'échappements horlogers par la théorie des engrenages
No full textIn principle, knowledge of watch and clock escapements is acquired through the study of the geometry and operation of numerous realizations, studied patiently one after the other. Knowing the classics, one can hope to construct a new realizations by borrowing components from one or geometry from another. Currently, there is no formal model or systematic approach which permits any other method of learning escapements and creating new ones. The purpose of this thesis is fill this gap by describing a formal model which will provide a systematic approach to escapements. We will not limit ourselves to the study of the geometry and operation of fundamental escapements but will add a formalism which has only been partially used in the past, outlining gear tooth profiles. The operation of proposed escapements will thus be characterized by an abstract geometric shape called the primitive outline. As opposed to visible escapement geometry, primitive outlines differ very little from one escapement to the other, making them an excellent basis for escapement unification. After going from existing geometries to primitive outlines we will reverse course. The method of outlining gear tooth profiles will allow us, based on existing primitive outlines, to construct new escapements. We will push this method to create a new primitive outline which, according to traditional criteria, appears to have unprecedented efficiency.INSTANT-LABLa mention sur la page de titre de la "Chaire Patek Philippe en conception micromécanique et horlogère" et rendue par "Laboratoire de conception micromécanique et horlogère