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Found 6289 publications

Structural analysis of titanium alloys

Ibolya Zsoldos K. Kulcsár J. Kónya

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

The material of choice for dental implant devices is titanium alloy (Ti-6Al-4V). In this study, the two fundamental manufacturing technologies of dental implant prostheses are compared. Titanium alloy specimens and models were created with conventional precision casting and with modern, innovative additive manufacturing technologies. Hereupon, the microscopic analysis of specimen cut-offs was carried out. We were focusing on fundamental microstructural differences. The thus-created specimen models were subjected to tensile tests for comparative examination.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012029

Investigating the relationship between the theoretical layer thickness of the graphite lubricant film and the Kudo's friction number in the case of forged parts.

Tamás Ibriksz F. Tancsics

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

In case of numerical analysis of forged parts, it is important to specify the friction coefficient characterizing the lubrication conditions. In our paper we present a combined method of a known SU (Simple Upsetting) deformation with EDS (Energy Dispersive Spectroscopy), which shows the relationship between the Kudo's friction number (this friction model is applicable for metalworking processes which produces high surface pressure) and the theoretical layer thickness of the graphite film covering the sink cavity. The tests were accomplished considering the solids content of non-synthetically produced lubricant concentrates diluted to varying degrees.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012047

Self-organising formation of fullerene molecules from graphene patterns

Ibolya Zsoldos Istvan Laszlo David Fulep

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

The self-organised formation of C60 and C70 from well designed graphene patterns was proved by molecular dynamic simulations. In this paper graphene nanopattern models are shown which can be used for self-organised formations of larger fullerene molecules. The rules of building of the nanopatterns are defined. Examples are shown for the self-organised processes in case of larger fullerene molecules.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012011

Structure and properties of closed-cell foam prepared from rPET

V. A. Szabó Gabor Dogossy

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

Nowadays, in the field of packaging technology, one-way polymer packaging materials are increasingly used. Food and packaging industry uses the most, the life cycle of which becomes short, they become waste very quick. Also included are light weight bottles of polyethylene terephthalate (PET). Large amounts of waste can be handled with multiple options. The worst is their dumping on dump sites, as these materials do not compost. Their thermal recycling is more favorable due to their high calorific value, but a real cycle can only be achieved by their physical recycling. However, during the multiple re-purposing, PET's mechanical and processing properties are reduced. In our research, chemical foaming has been investigated, resulting in a smaller weight, better specific property, and fully reusable product. During our investigations, the structure and mechanical properties of recycled PET (rPET) specimens manufactured with different composition, chain and foam additives were analyzed.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012043

Effect of locally increased melted layer thickness on the mechanical properties of laser sintered tool steel parts

Imre Fekete Tamás Ibriksz István Hatos András Lajos Nagy B. Kocsis H. Hargitai

Publication Name: Iop Conference Series Materials Science and Engineering

Publication Date: 2018-10-18

Volume: 426

Issue: 1

Page Range: Unknown

Description:

Additive technologies have several advantages over conventional manufacturing, such as the freedom of geometry of the products and internal structures. There are also some limitations and problems, deriving from stopping the process during the production. By restarting the process, the building often continues with a thicker starting layer due to the deposition of two or more layers. The effect of skipped melting of layers is investigated in this paper. Maraging steel powder (MS1) was used in direct metal laser sintering (DMLS) process to produce samples with increased thickness of melted layers. The layer thickness was increased in 20 μm steps up to 160 μm with 0.5 mm offset between the increased thickness layers. Porosity caused by the uneven melting was measured by optical microscope, mechanical tests were carried out to quantify the effect of skipped layers and fractured surfaces were observed under SEM. We have found that the yield strength and tensile strength are not affected if the layer thickness is slightly increased locally in the laser sintered part, while even a small increase in porosity greatly reduces the total elongation of the specimen. The decrease of impact energy due to the porosities shows similar correlation with the decrease of percentage elongation at break. However, the Charpy impact test is much more sensitive to layer skipping, the lack of melted layers lowers the impact strength significantly.

Open Access: Yes

DOI: 10.1088/1757-899X/426/1/012014

The effect of image feature qualifiers on fuzzy colorectal polyp detection schemes using KH interpolation - Towards hierarchical fuzzy classification of coloscopic still images

Brigita Sziová L. T. Kóczy Szilvia Nagy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2018-10-12

Volume: 2018-July

Issue: Unknown

Page Range: Unknown

Description:

Previous studies showed that intensities, intensity variation, edge densities, structural entropies of colonoscopy images and their wavelet transforms are good candidates for being selected as antecedents in fuzzy decision methods using KH interpolation for determining whether an image segment contains colorectal polyp segment. In the present consideration, we check which possible antecedent dimensions need interpolation, whether the average and variation of the gradients makes the classification more effective and whether some of the features can be omitted for some classes of images. The method is tested on three available databases consisting of images of three different resolutions, and according to the results, different resolutions, different types of polyps require different classification schemes, thus a hierarchical decision system needs to be built.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2018.8491479

On the existence and uniqueness of fixed points of fuzzy set valued sigmoid fuzzy cognitive maps

István Harmati L. T. Kóczy

Publication Name: IEEE International Conference on Fuzzy Systems

Publication Date: 2018-10-12

Volume: 2018-July

Issue: Unknown

Page Range: Unknown

Description:

Fuzzy cognitive maps are decision support tools, where the complex structure is modelled by a weighted, directed graph. The nodes represent specific characteristics of the modelled system, weighted and directed edges correspond to the direction and the strength of the relationship between the factors. The system state is identified by the values of the nodes which are computed by iteration. This process may lead to a fixed point, a limit cycle or produces chaotic behaviour. The type of behaviour depends on the weights, on the topology of the graph and on the function applied for the iteration. From the practical viewpoint, it is critical to know whether the iteration converges to a fixed point or not. In this article, we discuss this problem for the case when the weights or the values of the nodes are fuzzy numbers. This scenario may occur when linguistic variables, modelled by fuzzy numbers, describe the connections.

Open Access: Yes

DOI: 10.1109/FUZZ-IEEE.2018.8491447

Human-Centric Automation and Optimization for Smart Homes

János Botzheim Noel Nuo Wi Tay Naoyuki Kubota

Publication Name: IEEE Transactions on Automation Science and Engineering

Publication Date: 2018-10-01

Volume: 15

Issue: 4

Page Range: 1759-1771

Description:

A smart home needs to be human-centric, where it tries to fulfill human needs given the devices it has. Various works are developed to provide homes with reasoning and planning capability to fulfill goals, but most do not support complex sequence of plans or require significant manual effort in devising subplans. This is further aggravated by the need to optimize conflicting personal goals. A solution is to solve the planning problem represented as constraint satisfaction problem (CSP). But CSP uses hard constraints and, thus, cannot handle optimization and partial goal fulfillment efficiently. This paper aims to extend this approach to weighted CSP. Knowledge representation to help in generating planning rules is also proposed, as well as methods to improve performances. Case studies show that the system can provide intelligent and complex plans from activities generated from semantic annotations of the devices, as well as optimization to maximize personal constraints' fulfillment. Note to Practitioners - Smart home should maximize the fulfillment of personal goals that are often conflicting. For example, it should try to fulfill as much as possible the requests made by both the mother and daughter who wants to watch TV but both having different channel preferences. That said, every person has a set of goals or constraints that they hope the smart home can fulfill. Therefore, human-centric system that automates the loosely coupled devices of the smart home to optimize the goals or constraints of individuals in the home is developed. Automated planning is done using converted services extracted from devices, where conversion is done using existing tools and concepts from Web technologies. Weighted constraint satisfaction that provides the declarative approach to cover large problem domain to realize the automated planner with optimization capability is proposed. Details to speed up planning through search space reduction are also given. Real-time case studies are run in a prototype smart home to demonstrate its applicability and intelligence, where every planning is performed under a maximum of 10 s. The vision of this paper is to be able to implement such system in a community, where devices everywhere can cooperate to ensure the well-being of the community.

Open Access: Yes

DOI: 10.1109/TASE.2018.2789658

Detection of Human Footprint Alterations by Fuzzy Cognitive Maps Trained with Genetic Algorithm

Miklós F. Hatwágner Antonio Hernandez-Zavala Silvia L. Chaparro-Cardenas Julian Andres Ramirez-Bautista L. T. Kóczy Jorge A. Huerta-Ruelas

Publication Name: Proceedings of the Special Session 2018 17th Mexican International Conference on Artificial Intelligence Micai 2018

Publication Date: 2018-10-01

Volume: Unknown

Issue: Unknown

Page Range: 32-38

Description:

Mobility is an important part of our daily life, hence the good health of our lower extremities is essential. Gait analysis using kinetic data along with medical Decision Support System or Computer Aided Diagnosis provide to physicians support in gait disorder detection, the risk of foot ulcerations especially in diabetic patients, leg discrepancy, footprint pathologies, and many other applications in biomedical diagnosis. To increase confidence in the system, it is necessary to use a technique which uses a comprehensive reasoning and provide explanations to discover new relationships and combination of features. The present research is an attempt to assess the viability of investigating human footprint alterations using Fuzzy Cognitive Maps (FCM) combined with a Genetic Algorithm (GA), and it is part for preparation of investigating more efficient algorithms in the future. In the proposed method, GA is used to learn the weight matrix of an FCM model applied to identify alterations in the human footprint. Using historical plantar pressure data obtained by electronic platforms, combined with FCM and optimization algorithm, a promising outcome is presented in the field of Computer-Aided Diagnosis.

Open Access: Yes

DOI: 10.1109/MICAI46078.2018.00013