Estudio de una metodología de software para la predicción y análisis del balance paramétrico de buques para su aplicación en los criterios de estabilidad de segunda generación

El objetivo de ésta tesis es estudiar cómo desarrollar una aplicación informática que implemente algoritmos numéricos de evaluación de características hidrodinámicas de modelos geométricos representativos de carenas de buques. Se trata de especificar los requisitos necesarios que debe cumplir un programa para informático orientado a dar solución a un determinado problema hidródinámico, como es simular el comportamiento en balance de un buque sometido a oleaje, de popa o proa. una vez especificada la aplicación se realizará un diseño del programa; se estudiarán alternativas para implementar la aplicación; se explicará el proceso que ha de seguirse para obtener la aplicación en funcionamiento y se contrastarán los resultados obtenidos en la medida que sea posible. Se pretende sistematizar y sintetizar todo el proceso de desarrollo de software, orientado a la simulación del comportamiento hidrodinámico de un buque, en una metodología que se pondrá a disposición de la comunidad académica y científica en la forma que se considere más adecuada. Se trata, por tanto, de proponer una metodología de desarrollo de software para obetener una aplicación que facilite la evaluación de diferentes alternativas de estudio variando parámetros relativos al problema en estudio y que sea capaz de proporcionar resultados para su análisis. Así mismo se incide en cómo ha de conducirse en el proceso para que dicha aplicación pueda crecer, incorporando soluciones existentes no implementadas o nuevas soluciones que aparezcan en este ámbito de conocimiento. Como aplicación concreta de la aplicación se ha elegido implementar los algoritmos necesarios para evaluar la aparición del balance paramétrico en un buque. En el análisis de éste problema se considera de interés la representación geométrica que se hace de la carena del buque. Además de la carena aparecen otros elementos que tienen influencia determinante en éste estudio, como son las situación de mar y las situaciones de carga. Idealmente, el problema sería resuelto si se consiguiera determinar el ángulo de balance que se produce al enfrentar un buque a las diferentes condiciones de mar. Se pretende preparar un programa utilizando el paradigma de la orientación a objetos. Considero que es la más adecuada forma de modularizar el programa para poder utilizar diferentes modelos de una misma carena y así comparar los resultados de la evaluación del balance paramétrico entre sí. En una etapa posterior se podrían comparar los resultados con otros obtenidos empíricamente. Hablo de una nueva metodología porque pretendo indicar cómo se ha de construir una aplicación de software que sea usable y sobre la que se pueda seguir desarrollando. Esto justifica la selección del lenguaje de programación C++. Se seleccionará un núcleo geométrico de software que permita acoplar de forma versátil los distintos componentes de software que van a construir el programa. Este trabajo pretende aplicar el desarrollo de software a un aspecto concreto del área de conocimiento de la hidrodinámica. No se pretende aportar nuevos algoritmos para resolver problemas de hidrodinámica, sino diseñar un conjunto de objetos de software que implementen soluciones existentes a conocidas soluciones numéricas a dichos problemas. Se trata fundamentalmente de un trabajo de software, más que de hidrodinámica. Lo que aporta de novedad es una nueva forma de realizar un programa aplicado a los cálculos hidrodinámicos relativos a la determinación del balance paramétrico, que pueda crecer e incorporar cualquier novedad que pueda surgir más adelante. Esto será posible por la programación modular utilizada y los objetos que representan cada uno de los elementos que intervienen en la determinación del balance paramétrico. La elección de aplicar la metodología a la predicción del balance paramétrico se debe a que este concepto es uno de los elementos que intervienen en la evaluación de criterios de estabilidad de segunda generación que estan en estudio para su futura aplicación en el ámbito de la construcción naval. Es por tanto un estudio que despierta interés por su próxima utilidad. ABSTRACT The aim of this thesis is to study how to develop a computer application implementing numerical algorithms to assess hydrodynamic features of geometrical models of vessels. It is therefore to propose a methodology for software development applied to an hydrodynamic problem, in order to evaluate different study alternatives by varying different parameters related to the problem and to be capable of providing results for analysis. As a concrete application of the program it has been chosen to implement the algorithms necessary for evaluating the appearance of parametric rolling in a vessel. In the analysis of this problem it is considered of interest the geometrical representation of the hull of the ship and other elements which have decisive influence in this phenomena, such as the sea situation and the loading condition. Ideally, the application would determine the roll angle that occurs when a ship is on waves of different characteristics. It aims to prepare a program by using the paradigm of object oriented programming. I think it is the best methodology to modularize the program. My intention is to show how face the global process of developing an application from the initial specification until the final release of the program. The process will keep in mind the spefici objetives of usability and the possibility of growing in the scope of the software. This work intends to apply software development to a particular aspect the area of knowledge of hydrodynamics. It is not intended to provide new algorithms for solving problems of hydrodynamics, but designing a set of software objects that implement existing solutions to these problems. This is essentially a job software rather than hydrodynamic. The novelty of this thesis stands in this work focuses in describing how to apply the whole proccess of software engineering to hydrodinamics problems. The choice of the prediction of parametric balance as the main objetive to be applied to is because this concept is one of the elements involved in the evaluation of the intact stability criteria of second generation. Therefore, I consider this study as relevant usefull for the future application in the field of shipbuilding.

Polymorphism in the Spotlight: Studying its Prevalence in Java and Smalltalk

Subtype polymorphism is a cornerstone of object-oriented programming. By hiding variability in behavior behind a uniform interface, polymorphism decouples clients from providers and thus enables genericity, modularity and extensi- bility. At the same time, however, it scatters the implementation of the behavior over multiple classes thus potentially hampering program comprehension. The extent to which polymorphism is used in real programs and the impact of polymorphism on program comprehension are not very well understood. We report on a preliminary study of the prevalence of polymorphism in several hundred open source software systems written in Smalltalk, one of the oldest object-oriented programming languages, and in Java, one of the most widespread ones. Although a large portion of the call sites in these systems are polymorphic, a majority have a small number of potential candidates. Smalltalk uses polymorphism to a much greater extent than Java. We discuss how these findings can be used as input for more detailed studies in program comprehension and for better developer support in the IDE.

Hybrid knowledge representation in a blackboard KBS for liquid retaining structure design

This paper highlights the importance of design expertise, for designing liquid retaining structures, including subjective judgments and professional experience. Design of liquid retaining structures has special features different from the others. Being more vulnerable to corrosion problem, they have stringent requirements against serviceability limit state of crack. It is the premise of the study to transferring expert knowledge in a computerized blackboard system. Hybrid knowledge representation schemes, including production rules, object-oriented programming, and procedural methods, are employed to express engineering heuristics and standard design knowledge during the development of the knowledge-based system (KBS) for design of liquid retaining structures. This approach renders it possible to take advantages of the characteristics of each method. The system can provide the user with advice on preliminary design, loading specification, optimized configuration selection and detailed design analysis of liquid retaining structure. It would be beneficial to the field of retaining structure design by focusing on the acquisition and organization of expert knowledge through the development of recent artificial intelligence technology. (C) 2003 Elsevier Ltd. All rights reserved.

A knowledge-based system for liquid retaining structure design with blackboard architecture

Owing to the high degree of vulnerability of liquid retaining structures to corrosion problems, there are stringent requirements in its design against cracking. In this paper, a prototype knowledge-based system is developed and implemented for the design of liquid retaining structures based on the blackboard architecture. A commercially available expert system shell VISUAL RULE STUDIO working as an ActiveX Designer under the VISUAL BASIC programming environment is employed. Hybrid knowledge representation approach with production rules and procedural methods under object-oriented programming are used to represent the engineering heuristics and design knowledge of this domain. It is demonstrated that the blackboard architecture is capable of integrating different knowledge together in an effective manner. The system is tailored to give advice to users regarding preliminary design, loading specification and optimized configuration selection of this type of structure. An example of application is given to illustrate the capabilities of the prototype system in transferring knowledge on liquid retaining structure to novice engineers. (C) 2004 Elsevier Ltd. All rights reserved.

Tool support for executable documentation of Java class hierarchies

While object-oriented programming offers great solutions for today's software developers, this success has created difficult problems in class documentation and testing. In Java, two tools provide assistance: Javadoc allows class interface documentation to be embedded as code comments and JUnit supports unit testing by providing assert constructs and a test framework. This paper describes JUnitDoc, an integration of Javadoc and JUnit, which provides better support for class documentation and testing. With JUnitDoc, test cases are embedded in Javadoc comments and used as both examples for documentation and test cases for quality assurance. JUnitDoc extracts the test cases for use in HTML files serving as class documentation and in JUnit drivers for class testing. To address the difficult problem of testing inheritance hierarchies, JUnitDoc provides a novel solution in the form of a parallel test hierarchy. A small controlled experiment compares the readability of JUnitDoc documentation to formal documentation written in Object-Z. Copyright (c) 2005 John Wiley & Sons, Ltd.

Physiologically based synthetic models of hepatic disposition

Current Physiologically based pharmacokinetic (PBPK) models are inductive. We present an additional, different approach that is based on the synthetic rather than the inductive approach to modeling and simulation. It relies on object-oriented programming A model of the referent system in its experimental context is synthesized by assembling objects that represent components such as molecules, cells, aspects of tissue architecture, catheters, etc. The single pass perfused rat liver has been well described in evaluating hepatic drug pharmacokinetics (PK) and is the system on which we focus. In silico experiments begin with administration of objects representing actual compounds. Data are collected in a manner analogous to that in the referent PK experiments. The synthetic modeling method allows for recognition and representation of discrete event and discrete time processes, as well as heterogeneity in organization, function, and spatial effects. An application is developed for sucrose and antipyrine, administered separately and together PBPK modeling has made extensive progress in characterizing abstracted PK properties but this has also been its limitation. Now, other important questions and possible extensions emerge. How are these PK properties and the observed behaviors generated? The inherent heuristic limitations of traditional models have hindered getting meaningful, detailed answers to such questions. Synthetic models of the type described here are specifically intended to help answer such questions. Analogous to wet-lab experimental models, they retain their applicability even when broken apart into sub-components. Having and applying this new class of models along with traditional PK modeling methods is expected to increase the productivity of pharmaceutical research at all levels that make use of modeling and simulation.

Dealing with non-determinism in testing concurrent java components

The testing of concurrent software components can be difficult due to the inherent non-determinism present in these components. For example, if the same test case is run multiple times, it may produce different results. This non-determinism may lead to problems with determining expected outputs. In this paper, we present and discuss several possible solutions to this problem in the context of testing concurrent Java components using the ConAn testing tool. We then present a recent extension to the tool that provides a general solution to this problem that is sufficient to deal with the level of non-determinism that we have encountered in testing over 20 components with ConAn. © 2005 IEEE

A classification of concurrency failures in java components

The Java programming language supports concurrency. Concurrent programs are hard to test due to their inherent non-determinism. This paper presents a classification of concurrency failures that is based on a model of Java concurrency. The model and failure classification is used to justify coverage of synchronization primitives of concurrent components. This is achieved by constructing concurrency flow graphs for each method call. A producer-consumer monitor is used to demonstrate how the approach can be used to measure coverage of concurrency primitives and thereby assist in determining test sequences for deterministic execution.

Data driven graphical applications:a fluid approach

The inclusion of high-level scripting functionality in state-of-the-art rendering APIs indicates a movement toward data-driven methodologies for structuring next generation rendering pipelines. A similar theme can be seen in the use of composition languages to deploy component software using selection and configuration of collaborating component implementations. In this paper we introduce the Fluid framework, which places particular emphasis on the use of high-level data manipulations in order to develop component based software that is flexible, extensible, and expressive. We introduce a data-driven, object oriented programming methodology to component based software development, and demonstrate how a rendering system with a similar focus on abstract manipulations can be incorporated, in order to develop a visualization application for geospatial data. In particular we describe a novel SAS script integration layer that provides access to vertex and fragment programs, producing a very controllable, responsive rendering system. The proposed system is very similar to developments speculatively planned for DirectX 10, but uses open standards and has cross platform applicability. © The Eurographics Association 2007.

A Sensitive Metric of Class Cohesion

Metrics estimate the quality of different aspects of software. In particular, cohesion indicates how well the parts of a system hold together. A metric to evaluate class cohesion is important in object-oriented programming because it gives an indication of a good design of classes. There are several proposals of metrics for class cohesion but they have several problems (for instance, low discrimination). In this paper, a new metric to evaluate class cohesion is proposed, called SCOM, which has several relevant features. It has an intuitive and analytical formulation, what is necessary to apply it to large-size software systems. It is normalized to produce values in the range [0..1], thus yielding meaningful values. It is also more sensitive than those previously reported in the literature. The attributes and methods used to evaluate SCOM are unambiguously stated. SCOM has an analytical threshold, which is a very useful but rare feature in software metrics. We assess the metric with several sample cases, showing that it gives more sensitive values than other well know cohesion metrics.

Учебно-Методический Комплекс Дисциплины “Объектно-Ориентированный Анализ и Программирование на Языке С#”

* Упомянуто данное направление, так как курс читается студентам факультета Бизнес-Информатика Государственного Университета – Высшая Школа Экономики (г. Москва)

A Representation of Binary Matrices

Христина Костадинова, Красимир Йорджев - В статията се обсъжда представянето на произволна бинарна матрица с помощта на последователност от цели неотрицателни числа. Разгледани са някои предимства и недостатъци на това представяне като алтернатива на стандартното, общоприето представяне чрез двумерен масив. Показано е, че представянето на бинарните матрици с помощта на наредени n-торки от естествени числа води до по-бързи алгоритми и до съществена икономия на оперативна памет. Използуван е апарата на обектно-ориентираното програмиране със синтаксиса и семантиката на езика C++.

Аргументиращо мислене в обектно-ориентираното програмиране при изграждането на фундаментални знания за програмирането

Kiril Ivanov - Four criteria for estimating the degree of fundamental programming knowledge acquisition are formulated. The specificity of the proof-oriented thinking in object- oriented programming and its role in the learning of fundamentals are pointed. Two ways of reasoning are distinguished: with an only possible conclusion and with a multiple choice by search of balance between contradictory requirements. Examples of arguments that help considerably the students to understand the basic ideas related to the use of objects and classes in different stages of the software system development are given. Particular attention is paid to the influence of the proof-oriented thinking on the learners’ motivation and hence – on their fundamental knowledge acquisition.

What can practitioner perceptions tell us about our subject?

Part of the challenge of fostering learning is to open up learner minds to new possibilities or ways of thinking but is what we are encouraging learners to think really that different from the current practitioner conceptions? Having been uncomfortable with the focus of textbooks for the teaching of the core concept, the nature of a program, in the teaching of object-­oriented programming, we sought to discover how practitioner’s conceived the concept. Our findings provide a framework for understanding the different ways of conceiving the concept and the features that distinguish these conceptions. How could these conceptions and their critical features influence the focus in teaching especially in relation to computational thinking?