TREE-D-SEEK: A Framework for Retrieving Three-Dimensional Scenes

In this dissertation, a strategy and framework for retrieving 3D scenes is proposed. The strategy is to retrieve 3D scenes based on a unified approach for indexing content from disparate information sources and information levels. The TREE-D-SEEK framework implements the proposed strategy for retrieving 3D scenes and is capable of indexing content from a variety of corpora at distinct information levels. A semantic annotation model for indexing 3D scenes in the TREE-D-SEEK framework is also proposed. The semantic annotation model is based on an ontology for rapid prototyping of 3D virtual worlds. With ongoing improvements in computer hardware and 3D technology, the cost associated with the acquisition, production and deployment of 3D scenes is decreasing. As a consequence, there is a need for efficient 3D retrieval systems for the increasing number of 3D scenes in corpora. An efficient 3D retrieval system provides several benefits such as enhanced sharing and reuse of 3D scenes and 3D content. Existing 3D retrieval systems are closed systems and provide search solutions based on a predefined set of indexing and matching algorithms Existing 3D search systems and search solutions cannot be customized for specific requirements, type of information source and information level. In this research, TREE-D-SEEK—an open, extensible framework for retrieving 3D scenes—is proposed. The TREE-D-SEEK framework is capable of retrieving 3D scenes based on indexing low level content to high-level semantic metadata. The TREE-D-SEEK framework is discussed from a software architecture perspective. The architecture is based on a common process flow derived from indexing disparate information sources. Several indexing and matching algorithms are implemented. Experiments are conducted to evaluate the usability and performance of the framework. Retrieval performance of the framework is evaluated using benchmarks and manually collected corpora. A generic, semantic annotation model is proposed for indexing a 3D scene. The primary objective of using the semantic annotation model in the TREE-D-SEEK framework is to improve retrieval relevance and to support richer queries within a 3D scene. The semantic annotation model is driven by an ontology. The ontology is derived from a 3D rapid prototyping framework. The TREE-D-SEEK framework supports querying by example, keyword based and semantic annotation based query types for retrieving 3D scenes

Engineering scalable modelling Languages

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Escuela Politécnica Superior, Departamento de Ingeniería Informática. Fecha de lectura: 08-11-2019Esta tesis tiene embargado el acceso al texto completo hasta el 08-05-2021Model-Driven Engineering (MDE) aims at reducing the cost of system development by raising the level of abstraction at which developers work. MDE-based solutions frequently involve the creation of Domain-Specific Modelling Languages (DSMLs). WhilethedefinitionofDSMLsandtheir(sometimesgraphical)supportingenvironments are recurring activities in MDE, they are mostly developed ad-hoc from scratch. The construction of these environments requires high expertise by developers, which currently need to spend large efforts for their construction. This thesis focusses on the development of scalable modelling environments for DSMLs based on patterns. For this purpose, we propose a catalogue of modularity patterns that can be used to extend a modelling language with services related to modularization and scalability. More specifically, these patterns allows defining model fragmentation strategies, scoping and visibility rules, model indexing services, and scoped constraints. Once the patterns have been applied to the meta-model of a modelling language, we synthesize a customized modelling environment enriched with the defined services, which become applicable to both existing monolithic legacy models and new models. A second contribution of this thesis is a set of concepts and technologies to facilitate the creation of graphical editors. For this purpose, we define heuristics which identify structures in the DSML abstract syntax, and automatically assign their diagram representation. Using this approach, developers can create a graphical representation by default from a meta-model, which later can be customised. These contributions have been implemented in two Eclipse plug-ins called EMFSplitter and EMF-Stencil. On one hand, EMF-Splitter implements the catalogue of modularity patterns and, on the other hand, EMF-Stencil supports the heuristics and the generation of a graphical modelling environment. Both tools were evaluated in different case studies to prove their versatility, efficiency, and capabilitieEl Desarrollo de Software Dirigido por Modelos (MDE, por sus siglas en inglés) tiene como objetivo reducir los costes en el desarrollo de aplicaciones, elevando el nivel de abstracciónconelqueactualmentetrabajanlosdesarrolladores. Lassolucionesbasadas en MDE frecuentemente involucran la creación de Lenguajes de Modelado de Dominio Específico (DSML, por sus siglas en inglés). Aunque la definición de los DSMLs y sus entornos gráficos de modelado son actividades recurrentes en MDE, actualmente en la mayoría de los casos se desarrollan ad-hoc desde cero. La construcción de estos entornos requiere una alta experiencia por parte de los desarrolladores, que deben realizar un gran esfuerzo para construirlos. Esta tesis se centra en el desarrollo de entornos de modelado escalables para DSML basados en patrones. Para ello, se propone un catálogo de patrones de modularidad que se pueden utilizar para extender un lenguaje de modelado con servicios relacionados con la modularización y la escalabilidad. Específicamente, los patrones permiten definir estrategias de fragmentación de modelos, reglas de alcance y visibilidad, servicios de indexación de modelos y restricciones de alcance. Una vez que los patrones se han aplicado al meta-modelo de un lenguaje de modelado, se puede generar automáticamente un entorno de modelado personalizado enriquecido con los servicios definidos, que se vuelven aplicables tanto a los modelos monolíticos existentes, como a los nuevos modelos. Una segunda contribución de esta tesis es la propuesta de conceptos y tecnologías para facilitar la creación de editores gráficos. Para ello, definimos heurísticas que identifican estructuras en la sintaxis abstracta de los DSMLs y asignan automáticamente su representación en el diagrama. Usando este enfoque, los desarrolladores pueden crear una representación gráfica por defecto a partir de un meta-modelo. Estas contribuciones se implementaron en dos plug-ins de Eclipse llamados EMFSplitter y EMF-Stencil. Por un lado, EMF-Splitter implementa el catálogo de patrones y, por otro lado, EMF-Stencil implementa las heurísticas y la generación de un entorno de modelado gráfico. Ambas herramientas se han evaluado con diferentes casos de estudio para demostrar su versatilidad, eficiencia y capacidade

Topic and language specific internet search engine

In this paper we present the result of our project that aims to build a categorization-based topic-oriented Internet search engine. Particularly, we focus on the economic related electronic materials available on the Internet in Hungarian. We present our search service that harvests, stores and makes searchable the publicly available contents of the subject domain. The paper describes the search facilities and the structure of the implemented system with special emphasis on intelligent search algorithms and document processing methods

Verifying multi-threaded software using SMT-based context-bounded model checking

We describe and evaluate three approaches to model check multi-threaded software with shared variables and locks using bounded model checking based on Satisfiability Modulo Theories (SMT) and our modelling of the synchronization primitives of the Pthread library. In the lazy approach, we generate all possible interleavings and call the SMT solver on each of them individually, until we either find a bug, or have systematically explored all interleavings. In the schedule recording approach, we encode all possible interleavings into one single formula and then exploit the high speed of the SMT solvers. In the underapproximation and widening approach, we reduce the state space by abstracting the number of interleavings from the proofs of unsatisfiability generated by the SMT solvers. In all three approaches, we bound the number of context switches allowed among threads in order to reduce the number of interleavings explored. We implemented these approaches in ESBMC, our SMT-based bounded model checker for ANSI-C programs. Our experiments show that ESBMC can analyze larger problems and substantially reduce the verification time compared to state-of-the-art techniques that use iterative context-bounding algorithms or counter-example guided abstraction refinement

A metadata-enhanced framework for high performance visual effects

This thesis is devoted to reducing the interactive latency of image processing computations in visual effects. Film and television graphic artists depend upon low-latency feedback to receive a visual response to changes in effect parameters. We tackle latency with a domain-specific optimising compiler which leverages high-level program metadata to guide key computational and memory hierarchy optimisations. This metadata encodes static and dynamic information about data dependence and patterns of memory access in the algorithms constituting a visual effect – features that are typically difficult to extract through program analysis – and presents it to the compiler in an explicit form. By using domain-specific information as a substitute for program analysis, our compiler is able to target a set of complex source-level optimisations that a vendor compiler does not attempt, before passing the optimised source to the vendor compiler for lower-level optimisation. Three key metadata-supported optimisations are presented. The first is an adaptation of space and schedule optimisation – based upon well-known compositions of the loop fusion and array contraction transformations – to the dynamic working sets and schedules of a runtimeparameterised visual effect. This adaptation sidesteps the costly solution of runtime code generation by specialising static parameters in an offline process and exploiting dynamic metadata to adapt the schedule and contracted working sets at runtime to user-tunable parameters. The second optimisation comprises a set of transformations to generate SIMD ISA-augmented source code. Our approach differs from autovectorisation by using static metadata to identify parallelism, in place of data dependence analysis, and runtime metadata to tune the data layout to user-tunable parameters for optimal aligned memory access. The third optimisation comprises a related set of transformations to generate code for SIMT architectures, such as GPUs. Static dependence metadata is exploited to guide large-scale parallelisation for tens of thousands of in-flight threads. Optimal use of the alignment-sensitive, explicitly managed memory hierarchy is achieved by identifying inter-thread and intra-core data sharing opportunities in memory access metadata. A detailed performance analysis of these optimisations is presented for two industrially developed visual effects. In our evaluation we demonstrate up to 8.1x speed-ups on Intel and AMD multicore CPUs and up to 6.6x speed-ups on NVIDIA GPUs over our best hand-written implementations of these two effects. Programmability is enhanced by automating the generation of SIMD and SIMT implementations from a single programmer-managed scalar representation

Automated Complexity Based Assembly Time Estimation Method

The overall goal of this research is to create an automated assembly time estimation method that is accurate and repeatable in an effort to reduce the analysis time required in estimating assembly times. Often, design for assembly (DFA) approaches are not used in industry due to the amount of time required to train engineers in the use of DFA, the time required to conduct the analysis, and the product level of detail needed. To decrease the analysis time and effort required in implementing the assembly time estimation portion of DFA, a tool is needed to estimate the assembly time of products while reducing the amount of information required to be manually input from the designer. The Interference Detection Method (IDM) developed in this research retrieves part connectivity information from a computer-aided design (CAD) assembly model, based on a parts\u27 relative location in the assembly space. The IDM is used to create the bi-partite graphs that are parsed into complexity vectors used with the artificial neural network complexity connectivity method to predict assembly times. The IDM is compared to the Assembly Mate Method which creates the connectivity graph based on the assembly mates used in creating the assembly model in CAD (SolidWorks). The results indicate that the IDM has a similar but larger percent error in estimating assembly time than the AMM. However, the variance of the AMM is larger than the variance observed with the IDM. The AMM requires the assembly mates to create the connectivity graph, which may vary based on the designer creating the assembly model. The IDM, based on part location within the assembly model, is independent of any mates used to create the assembly. Finally, the assembly mate information is only stored in the SW assembly file, limiting the functionality of the AMM to SolidWorks assembly files. The IDM operates on the solid bodies in the assembly model, and therefore can be executed on an assembly after being imported by SW using common CAD exchange file types: assembly file (*.sldasm), IGES (*.iges), parasolid(*.x_t), and STEP (*.step;*.stp). The IDM was also trained and tested as a tool for use during the conceptual phase of the design process. Assembly models were reduced in fidelity to represent a solid model created early in the design process when detailed information regarding the part geometry is not known. The complexity vectors of the reduced fidelity model are used as the input into a modified complexity connectivity method to estimate assembly time. The results indicate that the IDM can be used to predict the assembly time of products early in the design phase and performs best using a neural network trained using complexity vectors from high fidelity models. To explore the potential for separating the objective handling times from the subjective insertion times, a Split Interference Detection Method is developed to use CAD part information to determine the handling time of the Boothroyd and Dewhurst assembly time estimation method and a modified complexity connectivity method approach is used to determine the insertion times. The handling and insertion times are separated because the handling times can be mostly determined using quantitative objective product information, while the insertion questions are subjective and cannot be quantitatively determined. The results suggest separation of the insertion and handling time does not reduce the percent error in estimating the assembly time of a product in comparison to the IDM. The handling portion of the SIDM can be used as a separate automated tool to determine the handling code and handling time of a product. The insertion portion of the Boothroyd and Dewhurst assembly time estimation method would still need to be calculated manually. The ultimate goal of this research is to develop and automated assembly time estimation method

An intelligent framework for dynamic web services composition in the semantic web

As Web services are being increasingly adopted as the distributed computing technology of choice to securely publish application services beyond the firewall, the importance of composing them to create new, value-added service, is increasing. Thus far, the most successful practical approach to Web services composition, largely endorsed by the industry falls under the static composition category where the service selection and flow management are done a priori and manually. The second approach to web-services composition aspires to achieve more dynamic composition by semantically describing the process model of Web services and thus making it comprehensible to reasoning engines or software agents. The practical implementation of the dynamic composition approach is still in its infancy and many complex problems need to be resolved before it can be adopted outside the research communities. The investigation of automatic discovery and composition of Web services in this thesis resulted in the development of the eXtended Semantic Case Based Reasoner (XSCBR), which utilizes semantic web and AI methodology of Case Based Reasoning (CBR). Our framework uses OWL semantic descriptions extensively for implementing both the matchmaking profiles of the Web services and the components of the CBR engine. In this research, we have introduced the concept of runtime behaviour of services and consideration of that in Web services selection. The runtime behaviour of a service is a result of service execution and how the service will behave under different circumstances, which is difficult to presume prior to service execution. Moreover, we demonstrate that the accuracy of automatic matchmaking of Web services can be further improved by taking into account the adequacy of past matchmaking experiences for the requested task. Our XSCBR framework allows annotating such runtime experiences in terms of storing execution values of non-functional Web services parameters such as availability and response time into a case library. The XSCBR algorithm for matchmaking and discovery considers such stored Web services execution experiences to determine the adequacy of services for a particular task. We further extended our fundamental discovery and matchmaking algorithm to cater for web services composition. An intensive knowledge-based substitution approach was proposed to adapt the candidate service experiences to the requested solution before suggesting more complex and computationally taxing AI-based planning-based transformations. The inconsistency problem that occurs while adapting existing service composition solutions is addressed with a novel methodology based on Constraint Satisfaction Problem (CSP). From the outset, we adopted a pragmatic approach that focused on delivering an automated Web services discovery and composition solution with the minimum possible involvement of all composition participants: the service provider, the requestor and the service composer. The qualitative evaluation of the framework and the composition tools, together with the performance study of the XSCBR framework has verified that we were successful in achieving our goal

Manufacturability analysis for non-feature-based objects

This dissertation presents a general methodology for evaluating key manufacturability indicators using an approach that does not require feature recognition, or feature-based design input. The contributions involve methods for computing three manufacturability indicators that can be applied in a hierarchical manner. The analysis begins with the computation of visibility, which determines the potential manufacturability of a part using material removal processes such as CNC machining. This manufacturability indicator is purely based on accessibility, without considering the actual machine setup and tooling. Then, the analysis becomes more specific by analyzing the complexity in setup planning for the part; i.e. how the part geometry can be oriented to a cutting tool in an accessible manner. This indicator establishes if the part geometry is accessible about an axis of rotation, namely, whether it can be manufactured on a 4th-axis indexed machining system. The third indicator is geometric machinability, which is computed for each machining operation to indicate the actual manufacturability when employing a cutting tool with specific shape and size. The three manufacturability indicators presented in this dissertation are usable as steps in a process; however they can be executed alone or hierarchically in order to render manufacturability information. At the end of this dissertation, a Multi-Layered Visibility Map is proposed, which would serve as a re-design mechanism that can guide a part design toward increased manufacturability