Publications

Nowadays, the environmental impact of a product is a major factor for the design team and for the end customer. To decrease the environmental impact of a product during its whole lifecycle, many design methods are available focusing on the multitude of data from the product once it is fully designed (Lifecycle Analysis etc ...). However, the design choices made in the early design stages have a crucial importance on the environmental impact of the chosen solution. It is therefore necessary to propose to the multidisciplinary design team a tool to help them choosing the best concept and the best way to produce it as early as possible. The emphasis in this paper is on Additive Manufacturing technologies, which are widely used in concept development. A design tool prototype is presented and evaluated in order to foster early eco-additive manufacturing of concepts.

The current trend of product design leads to a change in the collaborative working style. To find the most efficient way to exchange information on the digital mock-up of a product, a synchronous co-located collaborative design environment with recent technologies is in needed. A new groupware of multi-view system allows multiple users to have individual visual information of a domain-specific representation of digital mock-up. In this paper, we propose a case study for the development and testing of a co-located multi-view system in collaborative virtual reality, aiming at enhancing the multidisciplinary early collaborative design. An ergonomic method of Personas is introduced to the evaluation of the tool, considering various user performance. With a multidisciplinary mug design scenario, experiments are presented, validating the benefits of the proposed system.

This article presents a comparison of different haptic systems, which are designed to simulate flat Human Machine Interfaces (HMIs) like touchscreens in virtual environments (VEs) such as CAVEs, and their respective performance. We compare a tangible passive transparent slate to a classic tablet and a sensory substitution system. These systems were tested during a controlled experiment. The performance and impressions from 20 subjects were collected to understand more about the modalities in the given context. The results show that the preferences of the subjects are strongly related to the use-cases and needs. In terms of performance, passive haptics proved to be significantly useful, acting as a space reference and a real-time continuous calibration system, allowing subjects to have lower execution durations and relative errors. Sensory substitution induced perception drifts during the experiment, causing significant performance disparities, demonstrating the low robustness of perception when spatial cues are insufficiently available. Our findings offer a better understanding on the nature of perception drifts and the need of strong multisensory spatial markers for such use-cases in CAVEs. The importance of a relevant haptic modality specifically designed to match a precise use-case is also emphasized.

In a three-dimensional (3D) virtual environment (VE), proper collaboration between vibrotactile and force cues - two cues of the haptic modality - is important to facilitate task performance of human users. Many studies report that collaborations between multi-sensory cues follow maximum likelihood estimation (MLE). However, an existing work finds that MLE yields a mean and an amplitude mismatches when interpreting the collaboration between the vibrotactile and force cues. We thus proposed mean-shifted MLE and conducted a human study to investigate the mismatches. For the study, we created a VE to replicate the visual scene, the 3D interactive task, and the cues from the existing work. Our participants were biased to rely on the vibrotactile cue for their tasks, departing from unbiased reliance on both cues in the existing work. Assessments of task completion time and task accuracy validated the replication. We found that based on task accuracy MLE explained the cue collaboration to certain degrees, agreed with the existing work. Mean-shifted MLE remedied the mean mismatch, but maintained the amplitude mismatch. Further examinations revealed that the collaboration between both cues may not be entirely additive. This sheds an insight for proper modeling of the collaboration between the vibrotactile and force cues to aid interactive tasks in VEs.

This paper presents an AR system architecture for assisting complex assembly work by adding visual information superimposed on the physical assembly parts.

Tilt coordination technique is used for reproducing a sustained linear acceleration in driving simulation by tilting the simulator cabin. Thus a part of gravity is interpreted as a horizontal acceleration. Between the slow rotational motion limited by the rotational perception threshold of semi-circular canals of vestibular system and the fast change of acceleration to render, the design of coupling motions of rotation and translation plays a critical role in the realism of driving simulator. We present here an experiment focusing on longitudinal accelerations rendering with pitch tilt coordination technique. Eight drivers experienced the same accelerations and decelerations on a straight double-lane motorway. During the driving, we varied the pitch rate (4, 5, 6 and 7 °/s) and the pitch acceleration (8 and 30 °/s²) used to render these accelerations with the tilt coordination technique. We have found an acceptability threshold of about 6°/s, similar to the value found in our previous work on roll tilt rendering. We have also shown a strong role of pitch rotational acceleration on acceptability, involving that it should be taken into account to properly render accelerations with the tilt coordination technique.

The work in this article deals with the measurement of temperature fields inside and near the weld pool during laser welding. The laser source used for this study is a 7.5 kW CO2 laser, and the welded material is a UNS N08904 austenitic stainless steel. The principle behind the actual experimentation is relatively simple: the welding operation is recorded with a charge coupled device camera equipped with infrared filters; after calibrating the camera sensor and image processing, the temperature distribution in the weld pool and near the melted zone is revealed.

Este trabalho teve como objetivo desenvolver o inventário de ciclo de vida para madeira empregada na estrutura de telhado de edificações populares do Estado de São Paulo, com base na adaptação de inventários existentes na base de dados ecoinvent (versão 3.1) para a realidade da produção madeireira no Brasil. Considerou-se como sistema de produto a produção de 1m3 de madeira serrada de cambará proveniente de manejo florestal sustentável na Amazônia, desde a extração das toras até a peça de madeira serrada estocada em São Paulo. As informações nacionais foram obtidas da literatura. A despeito das semelhanças entre o sistema de produto da base ecoinvent e a realidade nacional na extração das toras na floresta, há diferenças referentes ao transporte até a serraria, ao desdobro das toras e à geração e destinação de resíduos: no Brasil, todas as etapas são executadas próximas à região de exploração, resultando em alterações no modelo de transporte, máquinas empregadas e resíduos gerados. Além disso, os valores de consumo de diesel e eletricidade apresentaram ordens de grandeza diferentes dos ICVs de referência. Com base nessa análise, conclui-se que a estrutura de dados dos ICVs existentes na base ecoinvent auxilia a construção de inventários nacionais e que a adaptação dos inventários é imprescindível para a realização de estudos de avaliação do ciclo de vida condizentes com as condições do Brasil. Entretanto, considerando as diferenças observadas, é recomendada a apuração dos índices de consumo nacionais por meio de verificação e coleta de dados inloco

O presente trabalho tem como objetivo discutir a estimativa de incertezas em ACV, utilizando três procedimentos de cálculo a partir de dados de inventários da produção de blocos cerâmicos de uma fábrica localizada no Estado de São Paulo (berço ao portão). O primeiro procedimento para a estimativa de incertezas consistiu na atribuição de modelos probabilísticos e seus parâmetros aos valores obtidos na fábrica. As distribuições de probabilidade foram selecionadas dentre as disponíveis no Simapro (versão 8.1.1.16). O segundo procedimento consistiu na aplicação das diretrizes do Ecoinvent versão 3.1 relativas a incertezas, adotandose valores padronizados de incerteza básica e incertezas adicionais da matriz Pedigree, com distribuição lognormal. O terceiro procedimento consistiu em uma mescla dos procedimentos prévios: adotou-se o primeiro procedimento para o cálculo da incerteza básica e a matriz Pedigree para a atribuição da incerteza adicional. Os ICVs foram inseridos com suas respectivas incertezas no Simapro e foram feitas simulações de Monte Carlo com parâmetros equivalentes para as três situações. Realizaram-se também análises de variância (ANOVA) para verificar a distribuição das incertezas entre o processo principal e os processos a montante. Observou-se que os procedimentos 1 e 2 são passíveis de adoção em estudos de ACV, a depender da disponibilidade de recursos e do nível de detalhamento do estudo em questão, sendo que o primeiro procedimento, que envolve o cálculo direto das incertezas associadas, tem potencial de agregar maior confiabilidade ao estudo de ACV, enquanto o segundo requer menor esforço para a estimativa de incertezas. Ambas as abordagens melhoram a qualidade do resultado final a ser comunicado em relação à divulgação de um valor determinístico único.

For more than one hundred years the industrial revolution explodes all over the world through the different technologies. All these technologies were developed to help and increase the human conditions in providing new products. However, this development demands more and more resources (e.g. energy, water, raw materials) and generates many undesirable consequences with our over consumptions and the industrial systems used for the production. With the development of the research in human health and on the ecosystems, one has capable to assess our potential negative impacts. It exists many model in order to assess the environmental impacts (environmental impacts are on the ecosystem and on human health), one of the most famous methodology is the Life Cycle Assessment (LCA) [1] [2] that is managed by the standard ISO 14040 and ISO 14044. However, even if this methodology is well-known, this one presents many limitations.