Desarrollo de frameworks con .NET

La expansión experimentada por la informática, las nuevas tecnologías e internet en los últimos años, no solo viene dada por la evolución del hardware subyacente, sino por la evolución del desarrollo de software y del crecimiento del número de desarrolladores. Este incremento ha hecho evolucionar el software de unos sistemas de gestión basados en ficheros, prácticamente sin interfaz gráfico y de unos pocos miles de líneas a grandes sistemas distribuidos multiplataforma. El desarrollo de estos grandes sistemas, requiere gran cantidad de personas involucradas en el desarrollo, y que las herramientas de desarrollo hayan crecido también para facilitar su análisis, diseño, codificación, pruebas, implantación y mantenimiento. La base de estas herramientas software las proveen las propias plataformas de desarrollo, pero la experiencia de los desarrolladores puede aportar un sinfín de utilidades y de técnicas que agilicen los desarrollos y cumplan los requisitos del software en base a la reutilización de soluciones lo suficientemente probadas y optimizadas. Dichas herramientas se agrupan ordenadamente, creando así frameworks personalizados, con herramientas de todo tipo, clases, controles, interfaces, patrones de diseño, de tal manera que se dan soluciones personalizadas a un amplio número de problemas para emplearlas cuantas veces se quiera, bien marcando directrices de desarrollo mediante el uso de patrones, bien con la encapsulación de complejidades de tal modo que los desarrolladores ya dispongan de componentes que asuman cierta lógica o cierta complejidad aliviando así la fase de construcción. En este trabajo se abordan temas sobre las tecnologías base y plataformas de desarrollo para poder acometer la creación de un framework personalizado, necesidades a evaluar antes de acometerlo, y técnicas a emplear para la consecución del mismo, orientadas a la documentación, mantenimiento y extensión del framework. La exposición teórica consiste en mostrar y evaluar los requisitos para crear un framework, requisitos de la plataforma de desarrollo, y explicar cómo funcionan las grandes plataformas de desarrollo actuales, que elementos los componen y su funcionamiento, así como marcar ciertas pautas de estructuración y nomenclatura que el desarrollo de un framework debe contemplar para su mantenimiento y extensión. En la parte metodológica se ha usado un subconjunto de Métrica V3, ya que para el desarrollo de controles no aplica dicha metodología en su totalidad, pero contempla el catálogo de requisitos, los casos de uso, diagramas de clase, diagramas de secuencia, etc… Aparte de los conceptos teóricos, se presenta un caso práctico con fines didácticos de cómo parametrizar y configurar el desarrollo bajo la plataforma .NET. Dicho caso práctico consiste en la extensión de un control de usuario genérico de la plataforma .NET, de tal modo que se aplican conceptos más allá del hecho de crear funciones como las funcionalidades que puede brindar un API. Conceptos sobre como extender y modificar controles ya existentes, que interactúan por medio de eventos con otros controles, con vistas a que ese nuevo control forme parte de una biblioteca de controles de usuario personalizados ampliamente divulgada. Los controles de usuario son algo que no solo tienen una parte funcional, sino que también tienen una parte visual, y definiciones funcionales distintas de las típicas del software de gestión, puesto que han de controlar eventos, visualizaciones mientras se dan estos eventos y requisitos no funcionales de optimización de rendimiento, etc… Para el caso práctico se toma como herramienta la plataforma de desarrollo .Net Framework, en todas sus versiones, ya que el control a extender es el control ListView y hacerlo editable. Este control está presente en todas las versiones de .NET framework y con un alto grado de reutilización. Esta extensión muestra además como se puede migrar fácilmente este tipo de extensiones sobre todos los frameworks. Los entornos de desarrollo usados son varias versiones de Visual Studio para el mostrar dicha compatibilidad, aunque el desarrollo que acompaña este documento esté realizado sobre Visual Studio 2013. ABSTRACT The expansion in computer science, new technologies and the Internet in recent years, not only is given by the evolution of the underlying hardware, but for the evolution of software development and the growing number of developers. This increase has evolved software from management systems based on files almost without graphical interface and a few thousand of code lines, to large multiplatform distributed systems. The development of these large systems, require lots of people involved in development, and development tools have also grown to facilitate analysis, design, coding, testing, deployment and maintenance. The basis of these software tools are providing by their own development platforms, but the experience of the developers can bring a lot of utilities and techniques to speed up developments and meet the requirements of software reuse based on sufficiently proven solutions and optimized. These tools are grouped neatly, creating in this way custom frameworks, with tools of all types, classes, controls, interfaces, design patterns,… in such a way that they provide customized solutions to a wide range of problems to use them many times as you want to occur, either by dialing development guidelines by using patterns or along with the encapsulation of complexities, so that developers already have components that take some logic or some complexity relieving the construction phase. This paper cover matters based on technologies and development platforms to undertake the creation of a custom framework, needs to evaluate before rush it and techniques to use in order to achieve it, a part from techniques oriented to documentation, maintenance and framework extension. The theoretical explanation consists in to demonstrate and to evaluate the requirements for creating a framework, development platform requirements, and explain how large current development platforms work, which elements compose them and their operation work, as well as mark certain patterns of structure and nomenclature that the development of a framework should include for its maintenance and extension. In the methodological part, a subset of Métrica V3 has been used, because of, for the development of custom controls this methodology does not apply in its entirety, but provides a catalogue of requirements, use cases, class diagrams, sequence diagrams, etc ... Apart from the theoretical concepts, a study case for teaching purposes about how to parameterize and configure the development under the .NET platform is presented. This study case involves the extension of a generic user control of the .NET platform, so that concepts apply beyond the fact of creating functions as the functionalities that can provide an API. Concepts on how to extend and modify existing controls that interact through events with other controls, overlooking that new control as a part of a custom user controls library widely publicized. User controls are something that not only have a functional part, but also have a visual part, and various functional definitions of typical management software, since that they have to control events, visualizations while these events are given and not functional of performance optimization requirements, etc ... For the study case the development platform .Net Framework is taken as tool, in all its versions, considering that control to extend is the ListView control and make it editable. This control is present in all versions of .NET framework and with a high degree of reuse. This extension also shows how you can easily migrate these extensions on all frameworks. The used development environments are several versions of Visual Studio to show that compatibility, although the development that accompanies this document is done on Visual Studio 2013.

Reconfigurable computing for Monte Carlo simulations: results and prospects of the Janus project

We describe Janus, a massively parallel FPGA-based computer optimized for the simulation of spin glasses, theoretical models for the behavior of glassy materials. FPGAs (as compared to GPUs or many-core processors) provide a complementary approach to massively parallel computing. In particular, our model problem is formulated in terms of binary variables, and floating-point operations can be (almost) completely avoided. The FPGA architecture allows us to run many independent threads with almost no latencies in memory access, thus updating up to 1024 spins per cycle. We describe Janus in detail and we summarize the physics results obtained in four years of operation of this machine; we discuss two types of physics applications: long simulations on very large systems (which try to mimic and provide understanding about the experimental non equilibrium dynamics), and low-temperature equilibrium simulations using an artificial parallel tempering dynamics. The time scale of our non-equilibrium simulations spans eleven orders of magnitude (from picoseconds to a tenth of a second). On the other hand, our equilibrium simulations are unprecedented both because of the low temperatures reached and for the large systems that we have brought to equilibrium. A finite-time scaling ansatz emerges from the detailed comparison of the two sets of simulations. Janus has made it possible to perform spin glass simulations that would take several decades on more conventional architectures. The paper ends with an assessment of the potential of possible future versions of the Janus architecture, based on state-of-the-art technology.

Towards Accurate and Efficient Description of Excited States

Thesis (Ph.D.)--University of Washington, 2016-06

Compositional class refinement in object-Z

Object-Z allows coupling constraints between classes which, on the one hand, facilitate specification at a high level of abstraction, but, on the other hand, make class refinement non-compositional. The consequence of this is that refinement is not practical for large Systems. This paper overcomes this limitation by introducing a methodology for compositional class refinement in Object-Z. The key step is an equivalence transformation of an arbitrary Object-Z specification to one in which introduced constraints prohibit non-compositional refinements. The methodology also allows the constraints which couple classes to be refined yielding an unrestricted approach to compositional class refinement.

Finite-size effects and error-free communication in Gaussian channels

The efficacy of a specially constructed Gallager-type error-correcting code to communication in a Gaussian channel is examined. The construction is based on the introduction of complex matrices, used in both encoding and decoding, which comprise sub-matrices of cascading connection values. The finite-size effects are estimated for comparing the results with the bounds set by Shannon. The critical noise level achieved for certain code rates and infinitely large systems nearly saturates the bounds set by Shannon even when the connectivity used is low.

Pragmatic approach to the development of robust real-time protocols

This research is concerned with the development of distributed real-time systems, in which software is used for the control of concurrent physical processes. These distributed control systems are required to periodically coordinate the operation of several autonomous physical processes, with the property of an atomic action. The implementation of this coordination must be fault-tolerant if the integrity of the system is to be maintained in the presence of processor or communication failures. Commit protocols have been widely used to provide this type of atomicity and ensure consistency in distributed computer systems. The objective of this research is the development of a class of robust commit protocols, applicable to the coordination of distributed real-time control systems. Extended forms of the standard two phase commit protocol, that provides fault-tolerant and real-time behaviour, were developed. Petri nets are used for the design of the distributed controllers, and to embed the commit protocol models within these controller designs. This composition of controller and protocol model allows the analysis of the complete system in a unified manner. A common problem for Petri net based techniques is that of state space explosion, a modular approach to both the design and analysis would help cope with this problem. Although extensions to Petri nets that allow module construction exist, generally the modularisation is restricted to the specification, and analysis must be performed on the (flat) detailed net. The Petri net designs for the type of distributed systems considered in this research are both large and complex. The top down, bottom up and hybrid synthesis techniques that are used to model large systems in Petri nets are considered. A hybrid approach to Petri net design for a restricted class of communicating processes is developed. Designs produced using this hybrid approach are modular and allow re-use of verified modules. In order to use this form of modular analysis, it is necessary to project an equivalent but reduced behaviour on the modules used. These projections conceal events local to modules that are not essential for the purpose of analysis. To generate the external behaviour, each firing sequence of the subnet is replaced by an atomic transition internal to the module, and the firing of these transitions transforms the input and output markings of the module. Thus local events are concealed through the projection of the external behaviour of modules. This hybrid design approach preserves properties of interest, such as boundedness and liveness, while the systematic concealment of local events allows the management of state space. The approach presented in this research is particularly suited to distributed systems, as the underlying communication model is used as the basis for the interconnection of modules in the design procedure. This hybrid approach is applied to Petri net based design and analysis of distributed controllers for two industrial applications that incorporate the robust, real-time commit protocols developed. Temporal Petri nets, which combine Petri nets and temporal logic, are used to capture and verify causal and temporal aspects of the designs in a unified manner.

Multiscale molecular dynamics/hydrodynamics implementation of two dimensional “Mercedes Benz” water model

A multiscale Molecular Dynamics/Hydrodynamics implementation of the 2D Mercedes Benz (MB or BN2D) [1] water model is developed and investigated. The concept and the governing equations of multiscale coupling together with the results of the two-way coupling implementation are reported. The sensitivity of the multiscale model for obtaining macroscopic and microscopic parameters of the system, such as macroscopic density and velocity fluctuations, radial distribution and velocity autocorrelation functions of MB particles, is evaluated. Critical issues for extending the current model to large systems are discussed.

A novel methodology for simulating contact-line behavior in capillary-driven flows

Despite the wide swath of applications where multiphase fluid contact lines exist, there is still no consensus on an accurate and general simulation methodology. Most prior numerical work has imposed one of the many dynamic contact-angle theories at solid walls. Such approaches are inherently limited by the theory accuracy. In fact, when inertial effects are important, the contact angle may be history dependent and, thus, any single mathematical function is inappropriate. Given these limitations, the present work has two primary goals: 1) create a numerical framework that allows the contact angle to evolve naturally with appropriate contact-line physics and 2) develop equations and numerical methods such that contact-line simulations may be performed on coarse computational meshes.

Fluid flows affected by contact lines are dominated by capillary stresses and require accurate curvature calculations. The level set method was chosen to track the fluid interfaces because it is easy to calculate interface curvature accurately. Unfortunately, the level set reinitialization suffers from an ill-posed mathematical problem at contact lines: a ``blind spot'' exists. Standard techniques to handle this deficiency are shown to introduce parasitic velocity currents that artificially deform freely floating (non-prescribed) contact angles. As an alternative, a new relaxation equation reinitialization is proposed to remove these spurious velocity currents and its concept is further explored with level-set extension velocities.

To capture contact-line physics, two classical boundary conditions, the Navier-slip velocity boundary condition and a fixed contact angle, are implemented in direct numerical simulations (DNS). DNS are found to converge only if the slip length is well resolved by the computational mesh. Unfortunately, since the slip length is often very small compared to fluid structures, these simulations are not computationally feasible for large systems. To address the second goal, a new methodology is proposed which relies on the volumetric-filtered Navier-Stokes equations. Two unclosed terms, an average curvature and a viscous shear VS, are proposed to represent the missing microscale physics on a coarse mesh.

All of these components are then combined into a single framework and tested for a water droplet impacting a partially-wetting substrate. Very good agreement is found for the evolution of the contact diameter in time between the experimental measurements and the numerical simulation. Such comparison would not be possible with prior methods, since the Reynolds number Re and capillary number Ca are large. Furthermore, the experimentally approximated slip length ratio is well outside of the range currently achievable by DNS. This framework is a promising first step towards simulating complex physics in capillary-dominated flows at a reasonable computational expense.

The conjugate gradient partitioned block frequency-domain for multichannel adaptive filtering

The conjugate gradient is the most popular optimization method for solving large systems of linear equations. In a system identification problem, for example, where very large impulse response is involved, it is necessary to apply a particular strategy which diminishes the delay, while improving the convergence time. In this paper we propose a new scheme which combines frequency-domain adaptive filtering with a conjugate gradient technique in order to solve a high order multichannel adaptive filter, while being delayless and guaranteeing a very short convergence time.

Analysis of distrubances in large interconnected power systems

World economies increasingly demand reliable and economical power supply and distribution. To achieve this aim the majority of power systems are becoming interconnected, with several power utilities supplying the one large network. One problem that occurs in a large interconnected power system is the regular occurrence of system disturbances which can result in the creation of intra-area oscillating modes. These modes can be regarded as the transient responses of the power system to excitation, which are generally characterised as decaying sinusoids. For a power system operating ideally these transient responses would ideally would have a “ring-down” time of 10-15 seconds. Sometimes equipment failures disturb the ideal operation of power systems and oscillating modes with ring-down times greater than 15 seconds arise. The larger settling times associated with such “poorly damped” modes cause substantial power flows between generation nodes, resulting in significant physical stresses on the power distribution system. If these modes are not just poorly damped but “negatively damped”, catastrophic failures of the system can occur. To ensure system stability and security of large power systems, the potentially dangerous oscillating modes generated from disturbances (such as equipment failure) must be quickly identified. The power utility must then apply appropriate damping control strategies. In power system monitoring there exist two facets of critical interest. The first is the estimation of modal parameters for a power system in normal, stable, operation. The second is the rapid detection of any substantial changes to this normal, stable operation (because of equipment breakdown for example). Most work to date has concentrated on the first of these two facets, i.e. on modal parameter estimation. Numerous modal parameter estimation techniques have been proposed and implemented, but all have limitations [1-13]. One of the key limitations of all existing parameter estimation methods is the fact that they require very long data records to provide accurate parameter estimates. This is a particularly significant problem after a sudden detrimental change in damping. One simply cannot afford to wait long enough to collect the large amounts of data required for existing parameter estimators. Motivated by this gap in the current body of knowledge and practice, the research reported in this thesis focuses heavily on rapid detection of changes (i.e. on the second facet mentioned above). This thesis reports on a number of new algorithms which can rapidly flag whether or not there has been a detrimental change to a stable operating system. It will be seen that the new algorithms enable sudden modal changes to be detected within quite short time frames (typically about 1 minute), using data from power systems in normal operation. The new methods reported in this thesis are summarised below. The Energy Based Detector (EBD): The rationale for this method is that the modal disturbance energy is greater for lightly damped modes than it is for heavily damped modes (because the latter decay more rapidly). Sudden changes in modal energy, then, imply sudden changes in modal damping. Because the method relies on data from power systems in normal operation, the modal disturbances are random. Accordingly, the disturbance energy is modelled as a random process (with the parameters of the model being determined from the power system under consideration). A threshold is then set based on the statistical model. The energy method is very simple to implement and is computationally efficient. It is, however, only able to determine whether or not a sudden modal deterioration has occurred; it cannot identify which mode has deteriorated. For this reason the method is particularly well suited to smaller interconnected power systems that involve only a single mode. Optimal Individual Mode Detector (OIMD): As discussed in the previous paragraph, the energy detector can only determine whether or not a change has occurred; it cannot flag which mode is responsible for the deterioration. The OIMD seeks to address this shortcoming. It uses optimal detection theory to test for sudden changes in individual modes. In practice, one can have an OIMD operating for all modes within a system, so that changes in any of the modes can be detected. Like the energy detector, the OIMD is based on a statistical model and a subsequently derived threshold test. The Kalman Innovation Detector (KID): This detector is an alternative to the OIMD. Unlike the OIMD, however, it does not explicitly monitor individual modes. Rather it relies on a key property of a Kalman filter, namely that the Kalman innovation (the difference between the estimated and observed outputs) is white as long as the Kalman filter model is valid. A Kalman filter model is set to represent a particular power system. If some event in the power system (such as equipment failure) causes a sudden change to the power system, the Kalman model will no longer be valid and the innovation will no longer be white. Furthermore, if there is a detrimental system change, the innovation spectrum will display strong peaks in the spectrum at frequency locations associated with changes. Hence the innovation spectrum can be monitored to both set-off an “alarm” when a change occurs and to identify which modal frequency has given rise to the change. The threshold for alarming is based on the simple Chi-Squared PDF for a normalised white noise spectrum [14, 15]. While the method can identify the mode which has deteriorated, it does not necessarily indicate whether there has been a frequency or damping change. The PPM discussed next can monitor frequency changes and so can provide some discrimination in this regard. The Polynomial Phase Method (PPM): In [16] the cubic phase (CP) function was introduced as a tool for revealing frequency related spectral changes. This thesis extends the cubic phase function to a generalised class of polynomial phase functions which can reveal frequency related spectral changes in power systems. A statistical analysis of the technique is performed. When applied to power system analysis, the PPM can provide knowledge of sudden shifts in frequency through both the new frequency estimate and the polynomial phase coefficient information. This knowledge can be then cross-referenced with other detection methods to provide improved detection benchmarks.

An evidence-based approach to professional development planning in large state educational systems

This paper presents a systems-level approach for adjudicating the prioritization, selection, and planning of inservcie professional development (PD) for teachers. We present a step-by-step model for documenting and assessing system-wide 'bids' for professional development programs

Parallel user profiling based on folksonomy for Large Scaled Recommender Systems : an implimentation of Cascading MapReduce

The Large scaled emerging user created information in web 2.0 such as tags, reviews, comments and blogs can be used to profile users’ interests and preferences to make personalized recommendations. To solve the scalability problem of the current user profiling and recommender systems, this paper proposes a parallel user profiling approach and a scalable recommender system. The current advanced cloud computing techniques including Hadoop, MapReduce and Cascading are employed to implement the proposed approaches. The experiments were conducted on Amazon EC2 Elastic MapReduce and S3 with a real world large scaled dataset from Del.icio.us website.

Knowledge management for enterprise systems: observations from small, medium and large organizations

Anecdotal evidence suggests that the lifecycle-wide management of Enterprise System (ES) related knowledge is critical for ES health and longevity. At a time where many ES-vendors now offering solutions to Small and Medium size organizations, this paper investigates the ability of Small and Medium size organizations to maintain a lifecycle-wide knowledge management strategy. The paper explores the alleged differences in the knowledge management practices across 27 small, medium and large organizations that had implemented a market-leading ES. Results suggest that: (1) despite similar knowledge creation efforts in all three organizational sizes, small organizations struggle with retaining, transferring and applying the knowledge. The study also reveals that, (2) the overall goodness of the knowledge management process in larger organizations remains higher than their small and medium counterparts.