A brazilian ergonomic human-robot interface case

Brazilian and foreign companies operating in Brazil in the last 30 years have been using automated productive resources, especially robots. These 3 decades doesńt seem to have been enough to develop in the actors involved with robots an adequate professional awareness. If we consider the predictive security and ergonomic aspects involved, we notice that there are critical failures on handling these situations. So in this study we tried to observe the presence of the human being in some workstations that operate with robots in the Brazilian Southeastern region. © (2013) Trans Tech Publications, Switzerland.

Mitigação de falhas críticas em sistemas produtivos.

O cenário competitivo e globalizado em que as empresas estão inseridas, sobretudo a partir do século XXI, associados a ciclos de vida cada vez menores dos produtos, rigorosos requisitos de qualidade, além de políticas de preservação do meio ambiente, com redução de consumo energético e de recursos hídricos, somadas às exigências legais de melhores condições de trabalho, resultaram em uma quebra de paradigma nos processos produtivos até então concebidos. Como solução a este novo cenário produtivo pode-se citar o extenso uso da automação industrial, fato que resultou em sistemas cada vez mais complexos, tanto do ponto de vista estrutural, em função do elevado número de componentes, quanto da complexidade dos sistemas de controle. A previsibilidade de todos os estados possíveis do sistema torna-se praticamente impossível. Dentre os estados possíveis pode-se citar os estados de falha que, dependendo da severidade do efeito associado à sua ocorrência, podem resultar em sérios danos para o homem, o meio ambiente e às próprias instalações, caso não sejam corretamente diagnosticados e tratados. Fatos recentes de catástrofes relacionadas à sistemas produtivos revelam a necessidade de se implementar medidas para prevenir e para mitigar os efeitos da ocorrência de falhas, com o objetivo de se evitar a ocorrência de catástrofes. De acordo com especialistas, os Sistemas Instrumentados de Segurança SIS, referenciados em normas como a IEC 61508 e IEC 61511, são uma solução para este tipo de problema. Trabalhos publicados tratam de métodos para a implementação de camadas SIS de prevenção, porém com escassez de trabalhos para camadas SIS de mitigação. Em função do desconhecimento da dinâmica do sistema em estado de falha, técnicas tradicionais de modelagem tornam-se inviáveis. Neste caso, o uso de inteligência artificial, como por exemplo a lógica fuzzy, pode se tornar uma solução para o desenvolvimento do algoritmo de controle, associadas a ferramentas de edição, modelagem e geração dos códigos de controle. A proposta deste trabalho é apresentar uma sistemática para a implementação de um sistema de controle para a mitigação de falhas críticas em sistemas produtivos, com referência às normas IEC 61508/61511, com ação antecipativa à ocorrência de catástrofes.

Direct comparison of the bond strength results of the different test methods: A critical literature review

Objective. The goal of this paper is to undertake a literature search collecting all dentin bond strength data obtained for six adhesives with four tests ( shear, microshear, tensile and microtensile) and to critically analyze the results with respect to average bond strength, coefficient of variation, mode of failure and product ranking. Method. A PubMed search was carried out for the years between 1998 and 2009 identifying publications on bond strength measurements of resin composite to dentin using four tests: shear, tensile, microshear and microtensile. The six adhesive resins were selected covering three step systems ( OptiBond FL, Scotch Bond Multi-Purpose Plus), two-step (Prime & Bond NT, Single Bond, Clear. l SE Bond) and one step (Adper Prompt L Pop). Results. Pooling results from 147 references showed an ongoing high scatter in the bond strength data regardless which adhesive and which bond test was used. Coefficients of variation remained high (20-50%) even with the microbond test. The reported modes of failure for all tests still included high number of cohesive failures. The ranking seemed to be dependant on the test used. Significance. The scatter in dentin bond strength data remains regardless which test is used confirming Finite Element Analysis predicting non-uniform stress distributions due to a number of geometrical, loading, material properties and specimens preparation variables. This reopens the question whether, an interfacial fracture mechanics approach to analyze the dentin - adhesive bond is not more appropriate for obtaining better agreement among dentin bond related papers. (C) 2009 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Hard real-time multiprocessor scheduling resilient to core failures

Presented at 21st IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (RTCSA 2015). 19 to 21, Aug, 2015, pp 122-131. Hong Kong, China.

Image guided critical screw placement precision in the cervical spine : important or incidental? : results of a series of 91 consecutive cases using OVEM

Study design: A retrospective study of image guided cervical implant placement precision. Objective: To describe a simple and precise classification of cervical critical screw placement. Summary of Background Data: "Critical" screw placement is defined as implant insertion into a bone corridor which is surrounded circumferentially by neurovascular structures. While the use of image guidance has improved accuracy, there is currently no classification which provides sufficient precision to assess the navigation success of critical cervical screw placement. Methods: Based on postoperative clinical evaluation and CT imaging, the orthogonal view evaluation method (OVEM) is used to classify screw accuracy into grade I (no cortical breach), grade la (screw thread cortical breach), grade II (internal diameter cortical breach) and grade III (major cortical breach causing neural or vascular injury). Grades II and III are considered to be navigation failures, after accounting for bone corridor / screw mismatch (minimal diameter of targeted bone corridor being smaller than an outer screw diameter). Results: A total of 276 screws from 91 patients were classified into grade I (64.9%), grade la (18.1%), and grade II (17.0%). No grade III screw was observed. The overall rate of navigation failure was 13%. Multiple logistic regression indicated that navigational failure was significantly associated with the level of instrumentation and the navigation system used. Navigational failure was rare (1.6%) when the margin around the screw in the bone corridor was larger than 1.5 mm. Conclusions: OVEM evaluation appears to be a useful tool to assess the precision of critical screw placement in the cervical spine. The OVEM validity and reliability need to be addressed. Further correlation with clinical outcomes will be addressed in future studies.

Rigorous development of safety-critical systems

Nowadays, computer-based systems tend to become more complex and control increasingly critical functions affecting different areas of human activities. Failures of such systems might result in loss of human lives as well as significant damage to the environment. Therefore, their safety needs to be ensured. However, the development of safety-critical systems is not a trivial exercise. Hence, to preclude design faults and guarantee the desired behaviour, different industrial standards prescribe the use of rigorous techniques for development and verification of such systems. The more critical the system is, the more rigorous approach should be undertaken. To ensure safety of a critical computer-based system, satisfaction of the safety requirements imposed on this system should be demonstrated. This task involves a number of activities. In particular, a set of the safety requirements is usually derived by conducting various safety analysis techniques. Strong assurance that the system satisfies the safety requirements can be provided by formal methods, i.e., mathematically-based techniques. At the same time, the evidence that the system under consideration meets the imposed safety requirements might be demonstrated by constructing safety cases. However, the overall safety assurance process of critical computerbased systems remains insufficiently defined due to the following reasons. Firstly, there are semantic differences between safety requirements and formal models. Informally represented safety requirements should be translated into the underlying formal language to enable further veri cation. Secondly, the development of formal models of complex systems can be labour-intensive and time consuming. Thirdly, there are only a few well-defined methods for integration of formal verification results into safety cases. This thesis proposes an integrated approach to the rigorous development and verification of safety-critical systems that (1) facilitates elicitation of safety requirements and their incorporation into formal models, (2) simplifies formal modelling and verification by proposing specification and refinement patterns, and (3) assists in the construction of safety cases from the artefacts generated by formal reasoning. Our chosen formal framework is Event-B. It allows us to tackle the complexity of safety-critical systems as well as to structure safety requirements by applying abstraction and stepwise refinement. The Rodin platform, a tool supporting Event-B, assists in automatic model transformations and proof-based verification of the desired system properties. The proposed approach has been validated by several case studies from different application domains.

The human side of project management - an investigation of critical chain concepts in the Argentinean Project Environment

The global marketplace is rapidly intensifying. Longer product sales lives, greater profit margins or simply survival, is dependent on management¿s ability to create and lead change. Project Management has become an important competency, combined with other business practices to adapt to the trend of changing conditions. Critical Chain is a relatively new project methodology, elaborated by Eliyahu Goldratt in order to complete projects faster, make more efficient use of resources and securing the project deliverables. The methodology is based on the assumption that traditional project techniques such as CPM and PERT, do not recognize critical human behavior. The methodology claims that many project failures are a direct result of how safety is built into the task delivery times, and then wasted by human behavior such as Student Syndrome, Parkinson Law and Multitasking. However, there has been little or no previous research regarding this topic in the Argentine marketplace. This study intended to investigate to what extent the human behavior concepts of critical chain project management are present, by performing in-depth interviews with Argentine project stakeholders. It appears that the four human behavior concepts are present in Argentina and that the majority of Argentine companies are yet to apply project management techniques.

Immunosuppressive drugs in organ transplant recipients--rationale for critical selection

Transplantation is the treatment of choice for many different organ failures. Despite growing experience in surgery and immunosuppression protocols, the long-term mortality of the procedure remains much higher than in the general population. Second only to cardiovascular diseases as the cause of death in organ transplant recipients, cancer is now known to be at least partly related to the immunosuppression regimen. Nevertheless, if calcineurin inhibitors have a demonstrated pro-oncogenic effect, other classes, such as mTOR inhibitors, are antiproliferative, and even demonstrated as an efficient therapy in some advanced oncological situations. Therefore, the adaptation of the therapy protocol evolves now towards an individualized medicine based on the risk factors of each transplant recipient in terms of cardiovascular, infectious and oncological diseases. As the first organ involved by tumor is the skin, many different guidelines have been published to try and adapt the therapy to the occurrence of a new lesion. If, for example, limited actinic keratosis or the first episode of a non-melanoma skin cancer usually requires no change of the immunosuppressive therapy, but a local specialized care and frequent clinical controls, more advanced lesions imply the adaptation of the drug regimen. In any case, the collaboration between general practitioners, dermatologists and the transplantation team is mandatory.

Land acquisition, investment, and development in the Lao coffee sector: Successes and failures

Despite the increasing acknowledgment of scholars and practitioners that many large-scale agricultural land acquisitions in developing countries fail or never materialize, empirical evidence about how and why they fail to date is still scarce. Too often, land deals are portrayed as straightforward investments and their success is taken for granted. Looking at the coffee sector in Laos, the authors of this article explore dimensions of the land grab debate that have not yet been sufficiently examined. Coffee concessionaires in southern Laos often fail to use all of the land granted them and fail to produce high yields on the land they do use. Thus, the authors challenge the often-assumed superiority and effectiveness of large-scale versus small-scale production, specifically the argument that they modernize agricultural production and optimize land use. They argue that examining failed investments is as important as studying successful ones for understanding the implications of the land grabbing phenomenon for social, economic, and environmental outcomes. Knowledge about the scale of “failed land deals” provides important motivation for national governments to close the gap between intentions and actual outcomes. This article engages with the current debate on quality of investment and challenges the approach of employing land concessions as a vehicle for economic development in the Lao coffee sector and in other sectors and countries.

Atom probe field ion microscope measurements of carbon segregation at an a:a grain boundary and service failures by intergranular stress corrosion cracking

This work reports on a critical measurement to understand the intergranular stress corrosion cracking (IGSCC) of pipeline steels: the atom probe field ion microscope (APFIM) measurement of the carbon concentration at a grain boundary (GB). The APFIM measurement was related to the microstructure and to IGSCC observations. The APFIM indicated that the GB carbon concentration of X70 was similar to 10 at% or less, which correlated with a high resistance to IGSCC for X70. (C) 2005 Elsevier Ltd. All rights reserved.

Developing intrinsically motivated information systems - a critical systems approach

This paper deals with the problematic of development methodologies for organisational information systems and especially with their application to business systems. Historically, information systems development methodologies tend to fail, because either they take the organisational purposefulness for granted, or they do not analyse it thoroughly. This paper's position is that the analysis, and the definition or redefinition of the systemic purpose are regarded as the utmost expression of the system 's purposefulness. This is to be achieved by ensuring the participation of all the stakeholders who affect, or are affected by, a particular business system's operations. The nature of participation, defined as a process of the stakeholders' perceptual exchanges, is deemed to be problematic in itself, due to the influence exerted upon it by organisational power, coercion and false consciousness. The paper highlights the philosophical reasons for the failures of information systems development methodologies, and provides a conceptual solution to this problematic as well as a strategy for the development of intrinsically motivated organisational information systems. The intrinsically motivated information systems methodology outlined here (BSPA) is intended to yield organisational information systems that demonstrably improve co-ordination of organisational activities, by enabling the development and maintenance of a single/multifaceted view of purpose throughout organisations.

The 3 per cent Barcelona Target: A Critical Appraisal of the Failure of the Lisbon Strategy’s Knowledgebased Economy and Society Project

Ten years after the unanimous approval of the Lisbon Strategy at a special meeting of the European Council on 23-24 March 2000 in Lisbon, it will be inevitable for the European Council, the European Commission and the majority of the EU member states to face with its fi asco and to account for the reasons of their fundamental policy, governance and economic failures in 2010. The recent turbulence of the global economy offers some excuses for the underperformance of the main objectives of the Lisbon Strategy in the essential social and economic domains, like job creation, economic growth, and environmental sustainability. Negative growth rates, macroeconomic and fi nancial instability, the contraction of the internal and external markets of the European economy, drop in demand for capital investment, goods and services, sinking corporate revenues, depreciation of corporate assets, increasing private and public indebtedness, falling rate of employment, weakening social cohesion, widening social inequality, and so forth not only deprive the majority of the EU member states of fulfi lling the main objectives of the Lisbon Strategy but also drive them into worse social and economic conditions in many policy domains than they were in 2000.

The Elastic Octopus: A Catalogue of Failures for Disrupting Design Eduction

Elastic Octopus was inspired by a perceived increased reluctance in student attitudes towards taking risks and failure in design innovation. In particular, recent trends in funding and risk-aversion in earlier phases of education where failures are discouraged has limited the potential for ground breaking innovative thinking. This experimental design project was conceived to tackle the failure reluctance trend by developing a team based cross-disciplinary masters level design innovation studio module where students would succeed in relation to their capacity to demonstrate failure. Principally this involved creating a permission giving process where ambitious design experiments are developed in order to encourage the transgression of edges and boundaries. This was achieved by adapting a number of creative design methods including blue-sky thinking, back casting and design exorcisms to challenge and de-programme failure aversion. Succeeding through failure involved transitioning from meta-themes through to experimental contexts where failures could be attempted as a way of exploring the limits of technologies, structures, mental models, human engagement and other factors critical to success. We hope that insights gained from this disruptive educational module can offer unexpected benefits for students ranging from increased failure resilience, through to narrative generation and context forming skills while at the same time providing wider value in discussing how designers deal with failure.

Probabilistic verification of satellite systems for mission critical applications

In this thesis, we present a quantitative approach using probabilistic verification techniques for the analysis of reliability, availability, maintainability, and safety (RAMS) properties of satellite systems. The subject of our research is satellites used in mission critical industrial applications. A strong case for using probabilistic model checking to support RAMS analysis of satellite systems is made by our verification results. This study is intended to build a foundation to help reliability engineers with a basic background in model checking to apply probabilistic model checking to small satellite systems. We make two major contributions. One of these is the approach of RAMS analysis to satellite systems. In the past, RAMS analysis has been extensively applied to the field of electrical and electronics engineering. It allows system designers and reliability engineers to predict the likelihood of failures from the indication of historical or current operational data. There is a high potential for the application of RAMS analysis in the field of space science and engineering. However, there is a lack of standardisation and suitable procedures for the correct study of RAMS characteristics for satellite systems. This thesis considers the promising application of RAMS analysis to the case of satellite design, use, and maintenance, focusing on its system segments. Data collection and verification procedures are discussed, and a number of considerations are also presented on how to predict the probability of failure. Our second contribution is leveraging the power of probabilistic model checking to analyse satellite systems. We present techniques for analysing satellite systems that differ from the more common quantitative approaches based on traditional simulation and testing. These techniques have not been applied in this context before. We present the use of probabilistic techniques via a suite of detailed examples, together with their analysis. Our presentation is done in an incremental manner: in terms of complexity of application domains and system models, and a detailed PRISM model of each scenario. We also provide results from practical work together with a discussion about future improvements.

Molecular Variations In Aromatic Cosolutes: Critical Role In The Rheology Of Cationic Wormlike Micelles.

Wormlike micelles formed by the addition to cetyltrimethylammonium bromide (CTAB) of a range of aromatic cosolutes with small molecular variations in their structure were systematically studied. Phenol and derivatives of benzoate and cinnamate were used, and the resulting mixtures were studied by oscillatory, steady-shear rheology, and the microstructure was probed by small-angle neutron scattering. The lengthening of the micelles and their entanglement result in remarkable viscoelastic properties, making rheology a useful tool to assess the effect of structural variations of the cosolutes on wormlike micelle formation. For a fixed concentration of CTAB and cosolute (200 mmol L(-1)), the relaxation time decreases in the following order: phenol > cinnamate> o-hydroxycinnamate > salicylate > o-methoxycinnamate > benzoate > o-methoxybenzoate. The variations in viscoelastic response are rationalized by using Mulliken population analysis to map out the electronic density of the cosolutes and quantify the barrier to rotation of specific groups on the aromatics. We find that the ability of the group attached to the aromatic ring to rotate is crucial in determining the packing of the cosolute at the micellar interface and thus critically impacts the micellar growth and, in turn, the rheological response. These results enable us for the first time to propose design rules for the self-assembly of the surfactants and cosolutes resulting in the formation of wormlike micelles with the cationic surfactant CTAB.