The assignment of the right fixtures to their corresponding workpieces and the determination of their stable flows is one of the important challenges for manufacturing systems. This problem has not been well addressed in the past publications. This paper aims to address this problem using an on-demand fixture assignment and control method. A decision support system (DSS) is presented so as to address this problem. This DSS integrates the case-based reasoning (CBR), rule-based reasoning (RBR) and fuzzy set theory components of an artificial intelligence (AI). Cases are represented with an object-oriented (OO) approach in order to characterize them by their feature vectors. A fuzzy weighted Euclidean distance measure is applied for case retrieval. Numerical example is also illustrated to show the applicability of the proposed DSS.
It is noticeable the growing of the various types of concerns in large centers, whether by citizens or public officials. In that sense, an important dimension is the crises management such as in cases of natural disasters. This scenario calls for a task force in an attempt to predict or solve emergencies, especially in managing and integrating public and private spheres, which in turn are centered on public authorities, service providers, citizens, volunteers and systems. In order to allow the exchange of information and joint actions of those involved entities, the fulfillment of interoperability requirements become a critical factor promoting improved performance of the actions taken in situations of crisis. Based on the literature and related worldwide initiatives, the main concerns and attributes of crisis management are identified from the perspective of interoperability. Founded on this knowledge a framework that supports a Disaster Response Management System (DRMS) development cycle is proposed. In this paper, a focus is done on a diagnostic step based on a Multi-criteria decision analysis (MCDA) in order to assess potential interoperability of a public entity or locality. The proposed MCDA method facilitates the specification of integrated solutions for the public sector to meet interoperability requirements in disaster management scenarios.
The objective of this article is to propose a conceptual model of a method of modelling processes adapted to Higher Education Institutions – HEI, based on the BPR – Business Process Reengineering. HEI is a type of company that has activity focused to provide services, but their operations have specific characteristics and a high level of complexity. The method can be applied in different processes in an HEI, because it covers specifics of the activity for possible significant improvements. To develop the method, the concepts such Operations Strategy added to concepts of Business Process Management, based on the reengineering of processes were applied. The key advantage is that the application of proposed method, can ensure that the process is aligned with the strategy. For the application of the method, a set of six stages are defined. Among the main objectives of process modelling as improvement of processes, at an HEI, you can set its strategy for a certain period; have a certain number of students enrolled in a particular discipline, in a certain language. Therefore, the core activity of the HEI is teaching, since the student must attend a number of disciplines, the institution will offer these disciplines, meeting their demand. However, to move it forward on its strategy, the HEI must not only offer this discipline, but also offer it in a definite language of the strategy plan. The text show an example of educational process modelled according proposed method and discusses the applicability for the different levels processes.
The use of active vibration control techniques applying piezoelectric actuators can show satisfactory results. This paper proposes an active vibration control technique based on H-infinity Norm, which is applied to a piezoelectric actuator bonded to a composite structure forming a so-called smart composite structure. The structural model is stablished for a rectangular shape beam by Serendipity type finite element based on first-order shear deformation theory with eight nodes, five degrees of freedom (DOF) per node and eight electrical DOF per piezoelectric. Furthermore, a mixed theory that uses a single equivalent layer for the discretization of the mechanical displacement field and a layerwise representation of the electrical field is adopted. Temperature effects are neglected. Simulation results show the effectiveness of the proposed control methodology for composite structures.
This paper proposes a method for deciding whether to insert an agile process as part of a waterfall project. Recently, many software projects adopt an agile software methodology. Still, some software is developed with traditional waterfall methodologies. Agile methods claim a strength of flexibility for uncertain changes, yet in some cases the initial expected scope of the project cannot be realized or undetected errors remain because schedules are fixed and unexpected backlog of tests and bug fixes remain unaddressed. On the other hand, a waterfall methodology can include high risk of violating schedule targets, while fulfilling the initially expected scope with comprehensive tests so that more complex products are reliable. For the decision whether to develop in waterfall or agile, our approach is to evaluate the effects on uncertainties by adoption of agile techniques. We begin with focus on uncertain rework. The effects on rework are evaluated as cost using simulation. The decision making problem is modeled as a decision tree. In the simulation, a Software Reliability Growth Model is used as an error likelihood and detection model. This proposed method is demonstrated using a simple shopping web site. As a case study, the effects on rework by adoption of agile can be evaluated using the developed simulator. With comparison of predicted rework costs given a balance of waterfall or agile methods for a specific case, the project can be designed more effectively.
Constant development of the vehicles energy efficiency, the fuel prices and the requirements for greenhouse gas emissions force designers to find new solutions to achieve the goals by minimising the movement resistances. As it was calculated basing on the research carried out at the Silesian University of Technology, the Institute of Fundamentals of Machinery Design on energy efficient cars designed for the Shell Eco-marathon race, the main component of the total resistance of a moving car is the aerodynamic drag which is equal, in such a type of car, to about 70% of the total movement resistance. The idea of the research is to optimize the shape of aerodynamic features of the front wheels surroundings. By the front wheel surroundings aerodynamic features, the front wheel arch and front bumper shapes are understood. The air drag depends on the elements of the drag coefficient cx which is strongly connected with its shape and its area. Front wheel in motion rotates and generates air turbulences which have negative influence on the car aerodynamics. In majority of the cars the front wheels are swivel, which makes it difficult or impossible to close the front wheel arch. For reduction of the air drag generated by the open wheel arch, three types of solutions are designed and optimized. The first solution is the main shape of the analysed car parts which are shaped so that they generate minimal aerodynamic drag and lead the air stream to bypass the wheel niche. The second analysed solution is passive system consisting of respectively shaped holes in the front bumper. The holes lead the air stream into the wheel niche, equalize pressure in the wheel niche and reduce the air turbulences generated by the rotating wheel. The last solution is a set of overlays which lead the air stream in such a way to avoid its disruption to the wheel arch niche and achieve the best air stream distribution around the vehicle.
This paper discusses an investigation into retrofitting a standard nautical Emergency Position Indicating Radio Beacon (EPIRB) on aicraft. The proposed solution will eject the EPIRB automatically away from the aircraft prior to water impact to ensure that it falls clear of any debris. For this system to be accepted by aircraft operators the retrofit needs to be cost effective and reliable with additionaly consideration being required for maintenance and installation. The selected location cannot interfere with the existing aircraft structural integrity and performance so as to avoid costly certification. The EPIRB ejecrion system will need to activate automatically under pre-determined conditions so as to allow succesful deployment of the EPIRB even if the aircraft breaks apart during descent. Once the beacon is in water the EPIRB will begin to transit GPS coordinates so its position is able to be tracked as it drifts on ocean currents.
The continuously increasing air traffic density has become a major challenge in air traffic control (ATC) due to the current ATC systems are approaching maximum capacity. To deal with the problem, an automated conflict resolution aid (CRA) and a trajectory prediction aid (TPA) have been proposed to serve as additional safety layers in the ATC systems. However, whether the proposed automation aids are worth to be applied in the current ATC workplace and could better support air traffic controllers (ATCOs) remain unknown. This study aims to investigate the effects of the proposed automations on ATCOs' workload and situation awareness (SA). To do so, twenty-four participants were evenly divided into two groups corresponding to the presence and absence of the TPA. In each condition, participants were instructed to perform simulated ATC tasks with the double of current air traffic load under the presence and absence of the CRA. The results showed that the CRA benefits ATCOs' workload and SA. The application of the CRA alone could benefit ATCOs while the presence of the TPA alone did not offer valuable benefits for ATCOs. Importantly, the CRA could lower the workload substantially when it was integrated with the TPA. The automation design aspect and its application in enhancing safety of future ATC are also highlighted.
Aircraft and aircraft components are redelivered to the next operator or owner during the phase-out process. During this process the operator is required by law and contract requirements to show compliance with maintenance procedures. At KLM E&M the phase-out documentation process is under increasing scrutiny as the number of aircraft phase-outs is assumed to rise in the coming years. The compliance process is investigated in order to measure, analyze and improve compliance with regard to maintenance data and record keeping during aircraft (component) redeliveries. For this purpose a benchmarking study is conducted to identify process bottlenecks. This study proved that in the case of KLM E&M phase-out, Landing Gears Life Limited Parts (LG LLPs) form the major bottleneck. Subsequently, an aircraft compliance model is developed to support the compliance cycle. As a case study, the documentation of LG LLPs of KLM's Boeing B737 aircraft fleet is investigated in this research. LG LLPs which are most frequently interchanged and installed on the nose gear miss the highest percentage of documentation necessary to prove back-to-birth traceability (a traceable history of a component over its life), which is a necessary feature from a phase-out perspective. On the basis of the compliance model and the observed data, several improvements to the phase-out process are proposed.
This paper demonstrates how decision-making techniques can be used to balance diverse stakeholder views, especially engineers from multiple disciplines, toward approaching suitable fire engineered solutions for steel structures. Forty-two fire design stakeholders were interviewed for their opinions on selecting a suitable fire protection for structural steel buildings. The stakeholders compared and rated decision attributes. Their views were assessed using the Group-Analytic Network Process (G-ANP). The results show the priority trends from aggregated fire design stakeholder views and systematic ranking of the fire protection options toward suitable decision-making thereby highlighting the viability of the decision analysis techniques for transdisciplinary collaboration in structural fire design.
In recent years, many e-commerce websites provide consumer feedback functions and social networks, allowing customers to share their purchasing and usage experiences online. Companies collect and analyze information from customers' reviews through the platform to understand the customers impressions of the products they purchased. Online customer reviews has been widely regarded as an important source of information influencing customers buying decisions. In addition, online customer reviews help companies to redesign their products with key features that better positions to target customers in promising market sectors. This research uses online customer reviews as the business intelligence (BI) corpus. After determining the source webpage of customer reviews, a web crawler is needed to collect customer review text. Afterwards, computer-assisted text mining, clustering analysis, and perceptual mapping are applied to develop a formal methodology to compare similar products in a given domain. In this research, the consumer electronic sector is studied. Mobile phone customer reviews are web crawled, collected, mined, and analyzed. The study assists mobile phone manufacturers to understand the voice of customers in both positive and negative perspectives of post-purchasing experiences. The customer-preferred product functions, hardware/software/app features, and price positions, as key business intelligence, are derived for new product designs and market launches.
This paper explores the metaheuristic Variable Neighborhood Search (VNS) to solve the static long-term power transmission network expansion planning problem that consists of finding the optimum expansion arrangement (construction of new circuits) for a horizon of defined planning. VNS is a simple and effective metaheuristic for combinatorial optimization that changes neighborhood within a local algorithm, and makes the choice of implementations that integrate intensification and/or diversification strategies during the search process. The formulation of the proposed method is presented, illustrating implementation details in the transmission network expansion planning problem using the transportation model. Results obtained in tests performed with a medium network available in literature are summarized.
This work presents the development of a data mining application for gait pattern classification. The objective is to understand the differences and similarities among patterns of walking from healthy and unhealthy subjects groups. The data repository contains the spatial parameters of centers of pressure (CoP) trajectories during gait. The trajectory of each CoP is extracted from the contact points of the feet with the ground form each footprint. The data was collected with a GaitRite® Pressure Sensor Mat. The proposed method includes the standardization of data and creation of an organized repository (data warehouse) from previously collected data. Also, it includes the development of a process mining example to analytical comparison between these two different groups. A graphical analysis based on decision tree provides the interpretation of the pattern of ‘signature’ footprints. This study is the starting point to classifying different pathologies and assisting the rehabilitation treatments.
This paper aims at studying the kinematic model of the 5R symmetrical parallel mechanism considering the uncertainties in the lengths of links and the clearances in the active joints. The complete kinematic model of the 5R parallel mechanism is formulated in the presence of the uncertain parameters that are model as random variables. The stochastic analysis, based on the Monte Carlo Method, permits to evaluate numerically the performance of the mechanism when the uncertain parameters are considered. Thus, the kinematic model for several poses within the workspace is evaluated. Moreover, the variability in the workspace produced by the uncertain parameters is also analyzed.
Object clustering is a fundamental task in many data analysis and pattern understanding applications by providing insights into detecting the underlying structures of a large collection of samples. In this paper, we present our work on a novel spectral clustering algorithm that partitions a collection of objects using the spectrum of adistance matrix. If the nodes in a metric space can be associated with a well defined distance, the distance matrix is almost negative definite, implying that the eigenvector for the smallest eigenvalues of this matrix can be used as an approximation of the solution to a quadratic form partition problem. It is proved that this smallest eigenvalue is equivalent to the second largest singular value. Therefore Lanczos iterative algorithm can be applied to findingthe eigenvalues efficiently. We adapted this algorithm to the distributed network community detection problem using a decentralized multi-agent framework, and tested the effectiveness of the proposed approach with simulations.
In the present scenario of search for quality and competitiveness, many companies use digital mockups to analyze performance, manufacturability, maintainability and other characteristics of products. Virtual prototyping, or DMU (Digital Mockup), consists of an environment where one can check products and processes, exchange information and make decisions, from the conceptual design stage through detailing. However, by restriction time or lack of appropriate guidelines, many of these activities are postponed or neglected. The present work aims to define a sequence of DMU analysis activities, applicable to different industries, able to reduce rework and assist architects and designers in identifying inconsistencies in digital mockups. Modeled in BPMN (Business Process Model and Notation) standard, the process proposed herein provides analysis in areas such as assembly, security, ergonomics, manufacturing, operation and maintenance. To verify the process applicability and consistency, the context of an agriculture equipment manufacturing company was considered. In this study, aligned with the principles of DSR (Design Science Research), it was necessary to identify the flow of activities involved (i.e. product architects and designers) as well as their needs and constraints. The evaluation of process performance was done through questionnaires submitted to stakeholders. From the application of the proposed solution, it is possible to reduce the number of reworks and identify problems in early stages of product development, thus contributing to improvement of quality indicators and competitiveness of enterprises.
Since 2012 the Smart Power Team has been actively participating in worldwide competition – the Shell Eco-marathon. From the beginning, the team has been working to increase driver's safety on the road by developing Advanced Driver Assistance Systems. This paper presents unique method for designing ADAS systems in order to minimize the costs of the design phase and system implementation and at the same time to maximize the positive effect the system has on driver and vehicle safety. The described method is based on using virtual prototyping tool to simulate the system performance in real life situations. This approach enabled an iterative design process, which resulted in reduction of errors with almost no prototyping and testing costs.
In the last few years, new methods to perform active vibration control were proposed and developed with the purpose of handling with several dynamic problems. These researches are motivated by the necessity of a safer and more efficient performance in the operation of mechanical systems (industrial applications). There are several types of actuators available for the active vibration control, the current work is dedicated on the Electromagnetic Actuator. This actuator uses electromagnetic forces to control the rotor without mechanical contact. And it is represented by a non-linear model, which justifies the control by Fuzzy Logic. In this work, the aim is to attenuate rotor system vibration by Fuzzy Logic based in Takagi-Sugeno model, the control is achieved using the linear quadratic regulator. Finally, the simulation results demonstrate efficiency of the methodology, which can be seen in the reduction of vibration amplitude.
The direct or indirect 3D scanning of the foot's plantar region can be used to manufacture customized insoles, orthosis and orthopedic shoes. The equipments that enable an efficient direct scanning are, in most cases, expensive and inaccessible to professionals. The inability to use such equipment, leads to recourse to indirect scanning with low-cost tools to generate the digital model. In this context, the aim of this study is to compare dimensionally the physical model with two virtual 3D models, one generated by a medium-cost equipment (MDX-40) and the other generated by a low-cost (Memento). To accomplish this goal a model in plaster of the plantar region of a healthy subject was made and later scanned by both methods. Five (5) regions or features of the plaster model were identified and measured. The dimensions were also virtually measured in a 3D CAD environment, in both scanned models. The methodology allowed to conclude that the 3D scanning made by MDX-40 presented a relative error of 0.72% compared to plaster model, while the Memento showed a relative error of 2.85%. In addition, the 3D scanning made by MDX-40 lasted 48 times longer than the Memento process. In view of the difference in cost and time for 3D scanning, the Memento can be considered more viable and interesting than the MDX-40, however, one study is necessary to evaluate the influence of the relative error in the quality of customized insoles.
Hydrogen fuel cell stack is used as a rare and sophisticated power source in nowadays electric cars. Our team has built ultra-light energy-efficient vehicle for research purposes that uses hydrogen fuel cell stack as a power source and electric engines as sole drive of the car. The problem of optimizing the operating parameters of the hydrogen fuel cell stack was solved by numerical simulation studies conducted on a simulation model of the hydrogen fuel cell stack. The paper presents a numerical simulation model of hydrogen fuel cell stack system developed in Matlab Simulink and the results of simulation allow the selection and optimization of the control parameters adapted to the specific conditions of use. The model reflects the performance characteristics of the cell and allows the simulation work and control of hydrogen fuel cell stacks composed of hydrogen tank, control valves and controller, sensors, energy buffer system (supercondensers) etc. The model of electric power source based on hydrogen fuel cell stack was built as a module that can be used in the previously developed simulation models of electric vehicles.
This paper presents the integrated product development tool Design for Autonomy for reengineering of foreign complex products. Design for Autonomy is a new member of the Design for X family, which aims at integrating the requirements from the X area, in this case autonomy, into the conceptual phase of the product development process. This tool regards to decision making activities and their outcomes: decisions about the interrelations with the design of products. The objective of Design for Autonomy is to assure that the product can be designed, produced and operated in Brazil for a defined period of time at a minimum risk of being dependent on export bans or unavailability of components. This can be accomplished by the Design for Autonomy model comprising four steps: (1) An analysis to identify critical elements and means for achieving their technological domain; (2) Preparation of nationalization; (3) Reverse engineering of the original product in order to obtain the technological know-how; and (4) Forward engineering including the adaptation for the new environment in Brazil, stimulating improvements and added value. In a pilot project, the Design for Autonomy tool is being successfully applied to the development of a Brazilian thrust vector control system, a subsystem used for attitude control of satellite launch vehicles. The technology originates from the German Aerospace Center (DLR) and is transferred to the Brazilian Institute of Aeronautics and Space (DCTA/IAE).
In the last two decades, technological and managerial changes are helping industrial organizations address the growing need to become more competitive, reducing production costs and delivering products that meet quality standards with higher performance. Two factors play a major role in this scenario. The first factor is the widespread application of automation technologies that make extensive use of intelligent information processing techniques, a paradigm that has been called Industry 4.0. The second factor is the adoption of the lean philosophy, with its focus on efficiency, effectiveness and waste reduction by emphasizing the core value that must be delivered to customers. Making decisions related to changes in a production environment usually involves considering aspects related to these factors and their relationships, which in most cases are non-trivial. This work is a historical review of the literature of the industrial revolution to the new industry 4.0, added the needs of automation use in lean production systems and supply chain characterization to develop a framework for integration of information systems and technologies in the stages of the chain value manufacturing.