From CAD to virtual reality: modelling approaches, data exchange and interactive 3D building design tools

Virtual reality has the potential to improve visualisation of building design and construction, but its implementation in the industry has yet to reach maturity. Present day translation of building data to virtual reality is often unidirectional and unsatisfactory. Three different approaches to the creation of models are identified and described in this paper. Consideration is given to the potential of both advances in computer-aided design and the emerging standards for data exchange to facilitate an integrated use of virtual reality. Commonalities and differences between computer-aided design and virtual reality packages are reviewed, and trials of current system, are described. The trials have been conducted to explore the technical issues related to the integrated use of CAD and virtual environments within the house building sector of the construction industry and to investigate the practical use of the new technology.

Supporting visual assessment of food and nutrient intake in a clinical care setting

Monitoring nutritional intake is an important aspect of the care of older people, particularly for those at risk of malnutrition. Current practice for monitoring food intake relies on hand written food charts that have several inadequacies. We describe the design and validation of a tool for computer-assisted visual assessment of patient food and nutrient intake. To estimate food consumption, the application compares the pixels the user rubbed out against predefined graphical masks. Weight of food consumed is calculated as a percentage of pixels rubbed out against pixels in the mask. Results suggest that the application may be a useful tool for the conservative assessment of nutritional intake in hospitals.

Towards the computer-aided diagnosis of dementia based on the geometric and network connectivity of structural MRI data

We present an intuitive geometric approach for analysing the structure and fragility of T1-weighted structural MRI scans of human brains. Apart from computing characteristics like the surface area and volume of regions of the brain that consist of highly active voxels, we also employ Network Theory in order to test how close these regions are to breaking apart. This analysis is used in an attempt to automatically classify subjects into three categories: Alzheimer’s disease, mild cognitive impairment and healthy controls, for the CADDementia Challenge.

Benefits from safer animal food products: preliminary results from a contingent valuation study of Italian households

The social cost of food scares has been the object of substantial applied research worldwide. In Italy, meat and dairy products are often the vectors of food-borne pathogens, and this is well known by the public. Most cases of food contamination and poisoning find their causes in the way food is handled after, rather than before purchase. However, a large fraction is still caused by mishandling at the industrial stage. With this in mind, we set out to estimate Italian households’ willingness to pay (WTP) for a reduction in the risk of meat and dairy food contamination using contingent valuation. The survey design incorporated features specifically conceived to overcome difficulties faced in previous survey research, especially with respect to individualized food expenditures and risk communication. In order to achieve this objective a CAPI (computer-assisted personal interview) survey was devised to tackle two major issues which emerged in previous contingent valuation studies. The first issue is connected to the way of communicating risk to consumers in order to allow them to make optimal choices and the second one to the results deriving from these studies. In fact, estimates from contingent valuation regarding food safety are given just for single products and so marketers may find it hard to extrapolate them to the aggregate. Our results show that in Italy there are segments of consumers who would benefit from higher standards of food safety for farm animal products.

Avaliação de um programa computacional para a medida da lordose lombar

Objetivo: métodos antropométricos que quantifiquem as curvas da coluna vertebral e a avaliação postural a fim de realizar investigações epidemiológicas sobre o papel da postura na ocorrência das dores lombares. O propósito do estudo foi avaliar acurácia e reprodutibilidade do Sistema de Avaliação Postural Digitalizado (SAPD) para medir lordose lombar comparando com raio-x. Delineamento: transversal, com amostra consecutiva. Participantes: para medida da acurácia no grupo 1 ( T12,L3,L5) n = 16 e grupo 2 (L1,L3,L5) n= 17. Na reprodutibilidade intra e inter-avaliador n= 80. Principais Medidas: marcadores externos nos processos espinhosos das vértebras T12, L1, L3 e L5. Raio-x de perfil da coluna lombar e foto digital em perfil direito. Medida da lordose lombar no raio-x com métodos de Cobb,Centróide (CLL) e Processos Espinhosos (PE) e com o SAPD. Resultados: grupo 1, correlação entre SAPD e Cobb foi 0,803 (p<0,001), entre SAPD e CLL foi 0,642 (p=0,024), entre SAPD e a medida dos PE a correlação foi 0,917, com R2 = 0,842. No grupo 2, correlação entre SAPD e Cobb foi 0,559 (p=0,020), entre SAPD e CLL de 0,325 (p=0,302), com correlação significativa somente entre SAPD e Cobb. Entre SAPD e PE a correlação foi 0,763, com R2 = 0,583. Para reprodutibilidade interavaliador a correlação foi 0,981 (p < 0,001) e para reprodutibilidade intra-avaliador de 0.978 (p < 0,001) referente às mesmas fotografias. Reprodutibilidade intraavaliador de 0.872 (p < 0.001) e 0.956 (p<0,001) para inter-avaliador referente à fotos diferentes de um mesmo indivíduo com recolocação dos marcadores sobre a pele . Considerações Finais: O SAPD mostrou-se acurado e reprodutível para a medida da lordose lombar.

A Framework supporting collaboration on the distributed design of integrated systems

The work described in this thesis aims to support the distributed design of integrated systems and considers specifically the need for collaborative interaction among designers. Particular emphasis was given to issues which were only marginally considered in previous approaches, such as the abstraction of the distribution of design automation resources over the network, the possibility of both synchronous and asynchronous interaction among designers and the support for extensible design data models. Such issues demand a rather complex software infrastructure, as possible solutions must encompass a wide range of software modules: from user interfaces to middleware to databases. To build such structure, several engineering techniques were employed and some original solutions were devised. The core of the proposed solution is based in the joint application of two homonymic technologies: CAD Frameworks and object-oriented frameworks. The former concept was coined in the late 80's within the electronic design automation community and comprehends a layered software environment which aims to support CAD tool developers, CAD administrators/integrators and designers. The latter, developed during the last decade by the software engineering community, is a software architecture model to build extensible and reusable object-oriented software subsystems. In this work, we proposed to create an object-oriented framework which includes extensible sets of design data primitives and design tool building blocks. Such object-oriented framework is included within a CAD Framework, where it plays important roles on typical CAD Framework services such as design data representation and management, versioning, user interfaces, design management and tool integration. The implemented CAD Framework - named Cave2 - followed the classical layered architecture presented by Barnes, Harrison, Newton and Spickelmier, but the possibilities granted by the use of the object-oriented framework foundations allowed a series of improvements which were not available in previous approaches: - object-oriented frameworks are extensible by design, thus this should be also true regarding the implemented sets of design data primitives and design tool building blocks. This means that both the design representation model and the software modules dealing with it can be upgraded or adapted to a particular design methodology, and that such extensions and adaptations will still inherit the architectural and functional aspects implemented in the object-oriented framework foundation; - the design semantics and the design visualization are both part of the object-oriented framework, but in clearly separated models. This allows for different visualization strategies for a given design data set, which gives collaborating parties the flexibility to choose individual visualization settings; - the control of the consistency between semantics and visualization - a particularly important issue in a design environment with multiple views of a single design - is also included in the foundations of the object-oriented framework. Such mechanism is generic enough to be also used by further extensions of the design data model, as it is based on the inversion of control between view and semantics. The view receives the user input and propagates such event to the semantic model, which evaluates if a state change is possible. If positive, it triggers the change of state of both semantics and view. Our approach took advantage of such inversion of control and included an layer between semantics and view to take into account the possibility of multi-view consistency; - to optimize the consistency control mechanism between views and semantics, we propose an event-based approach that captures each discrete interaction of a designer with his/her respective design views. The information about each interaction is encapsulated inside an event object, which may be propagated to the design semantics - and thus to other possible views - according to the consistency policy which is being used. Furthermore, the use of event pools allows for a late synchronization between view and semantics in case of unavailability of a network connection between them; - the use of proxy objects raised significantly the abstraction of the integration of design automation resources, as either remote or local tools and services are accessed through method calls in a local object. The connection to remote tools and services using a look-up protocol also abstracted completely the network location of such resources, allowing for resource addition and removal during runtime; - the implemented CAD Framework is completely based on Java technology, so it relies on the Java Virtual Machine as the layer which grants the independence between the CAD Framework and the operating system. All such improvements contributed to a higher abstraction on the distribution of design automation resources and also introduced a new paradigm for the remote interaction between designers. The resulting CAD Framework is able to support fine-grained collaboration based on events, so every single design update performed by a designer can be propagated to the rest of the design team regardless of their location in the distributed environment. This can increase the group awareness and allow a richer transfer of experiences among them, improving significantly the collaboration potential when compared to previously proposed file-based or record-based approaches. Three different case studies were conducted to validate the proposed approach, each one focusing one a subset of the contributions of this thesis. The first one uses the proxy-based resource distribution architecture to implement a prototyping platform using reconfigurable hardware modules. The second one extends the foundations of the implemented object-oriented framework to support interface-based design. Such extensions - design representation primitives and tool blocks - are used to implement a design entry tool named IBlaDe, which allows the collaborative creation of functional and structural models of integrated systems. The third case study regards the possibility of integration of multimedia metadata to the design data model. Such possibility is explored in the frame of an online educational and training platform.

Computer-Guided Surgery in Implantology: Review of Basic Concepts

The aim of the present study was to conduct a critical literature review about the technique of computer-guided surgery in implantology to highlight the indications, purposes, immediate loading of implants and complications, protocol of fabrication, and functioning of virtual planning software. This literature review was based on OLDMEDLINE and MEDLINE databases from 2002 to 2010 using the key words "computer-guided surgery" and "implant-supported prosthesis." Thirty-four studies regarding this topic were found. According to the literature review, it was concluded that the computer-assisted surgery is an excellent treatment alternative for patients with appropriate bone quantity for implant insertion in complete and partially edentulous arches. The Procera Nobel Guide software (Nobel Biocare) was the most common software used by the authors. In addition, the flapless surgery is advantageous for positioning of implants but with accurate indication. Although the computer-guided surgery may be helpful for virtual planning of cases with severe bone resorption, the conventional surgical technique is more appropriate. The surgical guide is important for insertion of the implants regardless of the surgical technique, and the success of immediate loading after computer-guided surgery depends on the accuracy of clinical and/or laboratorial steps.

DIRECT EXPRESSIONS FOR OGATA LEAD-LAG DESIGN METHOD USING ROOT LOCUS

Direct expressions for the design of a lead-lag continuous compensator using the root locus method and the procedure described in the 1970 and 1990 books by Ogata are presented. These results are useful in the Ogata design method because they avoid the geometrical determination of poles and zeros, making it easier to create a computer-based design.

Healing of dehiscence defects following root surface demineralization with tetracycline: A histologic study in monkeys

Background: the purpose of this study was to histologically evaluate the healing of experimental dehiscence defects after surface demineralization with tetracycline hydrochloride.Methods: Six adult male monkeys (Cebus apella) were used in this study. Dehiscence defects were surgically created on the buccal aspect of the mandibular lateral incisors in all animals. The root surfaces were debrided and planed. In a split-mouth design, a 10% tetracycline hydrochloride solution was applied to one tooth for 4 minutes (T group), followed by irrigation with saline. The contralateral tooth served as a control (C group). The flaps were repositioned and sutured. The animals were sacrificed at 6 months postoperatively and histological sections were processed. Computer-assisted histomorphometric analysis was used to evaluate the formation of new cementum, new bone, new connective tissue attachment, and length of the epithelium (junctional and sulcular).Results: Bone regeneration was similar in both groups (1.5 +/- 0.3 mm for the T group and 1.5 +/- 0.6 mm for the C group). The C group showed more new cementum than the T group (2.3 +/- 0.3 mm versus 2.2 +/- 0.3 mm) as well as a longer epithelium (1.0 +/- 0.3 mm versus 0.9 +/- 0.2 mm). The T group presented more new connective tissue attachment (3.1 +/- 0.2 mm) than the C group (2.9 +/- 0.6 mm). However, no statistically significant differences were detected between the two groups.Conclusions: the amount of new attachment was similar in both groups. Root conditioning with 10% tetracycline solution did not produce any additional new attachment in comparison to the controls.

Measurement of sealant surface area by clinical/computerized analysis: 11-year results.

OBJECTIVE: To analyze the clinical behavior of 2 pit and fissure sealants through clinical/computerized evaluation. METHOD AND MATERIALS: Occlusal sealants were placed on maxillary and mandibular first and second premolars according to a split-mouth design. All premolars were sealed with either Concise (3M Espe) or Prisma Shield (Caulk/Dentsply) sealant agents. A hematoxylin-based staining solution was applied on the occlusal surface 7 days, 18 months, 36 months, and 11 years after occlusal sealing to allow checking of the sealant material on the surface. At each analysis time all occlusal surfaces were photographed, and the photographs corresponding to each time period were analyzed with SigmaScan 4.0 Software. The alterations of the sealed area of each sealant were analyzed with the software and recorded. Next, the measurements of the areas were tabulated and analyzed according to each period. Analysis of variance (ANOVA), with parts subdivided into time, and the t test, with a significance level of 5%, were used. RESULTS: The greatest sealed area was maintained by the sealant Concise. However, over the course of 11 years, all sealants began to show the same level of alteration in sealed area. CONCLUSION: The sealing materials showed alteration in sealed area over time, but they were efficient in controlling caries lesion formation on premolar pits and fissures.

A survey of radiographic measurement estimation in assessment of dental implant length.

The aim of this study is to survey radiographic measurement estimation in the assessment of dental implant length according to dentists' confidence. A 19-point questionnaire with closed-ended questions was used by two graduate students to interview 69 dentists during a dental implant meeting. Included were 12 questions related to over- and underestimation in three radiographic modalities: panoramic (P), conventional tomography (T), and computerized tomography (CT). The database was analyzed by Epi-Info 6.04 software and the values from two radiographic modalities, P and T, were compared using a chi2 test. The results showed that 38.24% of the dentists' confidence was in the overestimation of measurements in P, 30.56% in T, and 0% in CT. On the other hand, considering the underestimated measurements, the percentages were 47.06% in P, 33.33% in T, and 1.92% in CT. The frequency of under- and overestimation were statistically significant (chi2 = 6.32; P = .0425) between P and T. CT was the radiographic modality with higher measurement precision according to dentists' confidence. In conclusion, the interviewed dentists felt that CT was the best radiographic modality when considering the measurement estimation precision in preoperative dental implant assessment.

Accuracy of impression techniques for implants. Part 1 - Influence of transfer copings surface abrasion

Purpose: This study evaluated the influence of surface abrasion of transfer copings to obtain a precise master cast for a partially edentulous restoration with different inclinations. Materials and Methods: Replicas (N = 30) of a metal matrix (control group) containing two implants at 90° and 65° in relation to the benchtop were obtained using a polyether impression material and three impression techniques: square impression copings splint with dental floss and autopolymerizing acrylic resin (TRS), square impression copings abraded with aluminum oxide (TA), and square impression copings abraded with aluminum oxide and adhesive-coated (TAA). The replicas obtained in type V stone were digitalized, and the images were exported to AutoCAD software to perform the readings of possible degree alterations in implant inclinations. The results were submitted to analysis of variance (ANOVA) and Tukey test (α < 0.05). Results: Comparing the techniques with regard to the 90° implant inclination, no statistical difference was observed between the three techniques and the control group. Analyzing the three techniques with regard to the 65° implant inclination, no significant difference was seen between technique TA and the control group. Conclusions: Technique TA presented more accurate master casts than TRS and TAA techniques. The angulated implant (65°) tended to generate more imprecise master casts than implants perpendicular to the surface. © 2008 by The American College of Prosthodontists.

Digital system design process automation using place/transition petri nets

The constant increase in digital systems complexity definitely demands the automation of the corresponding synthesis process. This paper presents a computational environment designed to produce both software and hardware implementations of a system. The tool for code generation has been named ACG8051. As for the hardware synthesis there has been produced a larger environment consisting of four programs, namely: PIPE2TAB, AGPS, TABELA, and TAB2VHDL. ACG8051 and PIPE2TAB use place/transition net descriptions from PIPE as inputs. ACG8051 is aimed at generating assembly code for the 8051 micro-controller. PIPE2TAB produces a tabular version of a Mealy type finite state machine of the system, its output is fed into AGPS that is used for state allocation. The resulting digital system is then input to TABELA, which minimizes control functions and outputs of the digital system. Finally, the output generated by TABELA is fed to TAB2VHDL that produces a VHDL description of the system at the register transfer level. Thus, we present here a set of tools designed to take a high-level description of a digital system, represented by a place/transition net, and produces as output both an assembly code that can be immediately run on an 8051 micro-controller, and a VHDL description that can be used to directly implement the hardware parts either on an FPGA or as an ASIC.

Influence of apical enlargement in cleaning and extrusion in canals with mild and moderate curvatures

Optical microscopy and morphometric analysis were used in this study to evaluate, in vitro, the cleaning of the apical region in root canals with mild or moderate curvatures subjected to biomechanical preparation with a rotary system, as well as to assess the amount of extruded material to the periapical area. Lateral incisors (n = 32), 16 with curvature angles smaller or equal to 10° (GI) and 16 between 11° and 25° angles (GII) were submitted to Hero 642 rotary instrumentation with different surgical diameters: (A) 30.02 and (B) 45.02. Irrigation was performed at each change of instrument with 5 mL of ultrapure Milli-Q water and the extruded material through the apical foramen was collected. Root cross-sections were subjected to histological analysis by optical microscopy (×40) and the images were evaluated morphometrically using the Image Tool software. Quantification of the extruded material was performed by weighing after liquid evaporation. ANOVA showed no statistically significant differences (p>0.05) among the groups with respect to the procedures used to clean the apical region. Considering the amount of extruded material, the Tukey's HSD showed that canals with mild curvature prepared with the 45.02 surgical diameter showed significantly higher values (p<0.05) that those of the other groups, which were similar between themselves (p>0.05). In conclusion, the effect of cleaning the apical region did not differ in the groups, considering root curvature and the surgical diameter of instruments used for apical preparation. The amount of extruded material was greater in canals with mild curvature that were prepared with the 45.02 surgical instrument diameter.

Methodology analysis of a computational tool used in electronic circuit design

This paper considers the importance of using a top-down methodology and suitable CAD tools in the development of electronic circuits. The paper presents an evaluation of the methodology used in a computational tool created to support the synthesis of digital to analog converter models by translating between different tools used in a wide variety of applications. This tool is named MS 2SV and works directly with the following two commercial tools: MATLAB/Simulink and SystemVision. Model translation of an electronic circuit is achieved by translating a mixed-signal block diagram developed in Simulink into a lower level of abstraction in VHDL-AMS and the simulation project support structure in SystemVision. The method validation was performed by analyzing the power spectral of the signal obtained by the discrete Fourier transform of a digital to analog converter simulation model. © 2011 IEEE.