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61.
E. Paz J. Abenojar Y. Ballesteros F. Forriol N. Dunne J. C. del Real 《Journal of materials science. Materials in medicine》2016,27(4):72
The basic formulation of an acrylic bone cement has been modified by the addition of a block copolymer, Nanostrength® (NS), in order to augment the mechanical properties and particularly the fracture toughness of the bone cement. Two grades of NS at different levels of loading, between 1 and 10 wt.%, have been used. Mechanical tests were conducted to study the behaviour of the modified cements; specific tests measured the bend, compression and fracture toughness properties. The failure mode of the fracture test specimens was analysed using scanning electron microscopy (SEM). The effect of NS addition on the thermal properties was also determined, and the polymerisation reaction using differential scanning calorimetry. It was observed that the addition of NS produced an improvement in the fracture toughness and ductility of the cement, which could have a positive contribution by reducing the premature fracture of the cement mantle. The residual monomer content was reduced when the NS was added. However this also produced an increase in the maximum temperature and the heat delivered during the polymerisation of the cement. 相似文献
62.
When performing a classification task, we may find some data-sets with a different class distribution among their patterns. This problem is known as classification with imbalanced data-sets and it appears in many real application areas. For this reason, it has recently become a relevant topic in the area of Machine Learning.The aim of this work is to improve the behaviour of fuzzy rule based classification systems (FRBCSs) in the framework of imbalanced data-sets by means of a tuning step. Specifically, we adapt the 2-tuples based genetic tuning approach to classification problems showing the good synergy between this method and some FRBCSs.Our empirical results show that the 2-tuples based genetic tuning increases the performance of FRBCSs in all types of imbalanced data. Furthermore, when the initial Rule Base, built by a fuzzy rule learning methodology, obtains a good behaviour in terms of accuracy, we achieve a higher improvement in performance for the whole model when applying the genetic 2-tuples post-processing step. This enhancement is also obtained in the case of cooperation with a preprocessing stage, proving the necessity of rebalancing the training set before the learning phase when dealing with imbalanced data. 相似文献
63.
Francisco J. Pino Author Vitae Oscar Pedreira Author Vitae 《Journal of Systems and Software》2010,83(10):1662-1677
For software process improvement - SPI - there are few small organizations using models that guide the management and deployment of their improvement initiatives. This is largely because a lot of these models do not consider the special characteristics of small businesses, nor the appropriate strategies for deploying an SPI initiative in this type of organization. It should also be noted that the models which direct improvement implementation for small settings do not present an explicit process with which to organize and guide the internal work of the employees involved in the implementation of the improvement opportunities. In this paper we propose a lightweight process, which takes into account appropriate strategies for this type of organization. Our proposal, known as a “Lightweight process to incorporate improvements”, uses the philosophy of the Scrum agile method, aiming to give detailed guidelines for supporting the management and performance of the incorporation of improvement opportunities within processes and their putting into practice in small companies. We have applied the proposed process in two small companies by means of the case study research method, and from the initial results, we have observed that it is indeed suitable for small businesses. 相似文献
64.
Lei Xie Monika Leester-Schädel Gerhard Ziegmann Stephanus Büttgenbach 《Microsystem Technologies》2010,16(6):1009-1013
Micro injection molded polymeric parts coated with functional thin films/layers show off the promising applications in microsystems
area. But the unfavorable and unavoidable defect of weld line in micro injection molding part leads to detrimental mechanical
and surface properties. The possibility of the functional thin film for enhancing micro injection molded weld lines was investigated.
Two typical coating materials (aluminum and titanium) with various film thicknesses (400, 600, 800 nm) were deposited on one
side of the micro injection molded weld line tensile sample via physical vapor deposition (PVD) method. The coated micro weld
line samples were characterized by tensile tests. The results show that PVD films of aluminum and titanium can reinforce the
strength and stiffness of micro injection molded weld line, even at thin thickness levels. But when the film thickness is
increasing, the weaker adhesion between metallic films and polymers decreased the PVD films’ enhancing performance for micro
weld line mechanical properties due to the degradation of polymers related to longer time exposure under high temperature. 相似文献
65.
We investigate quantitative extensions of modal logic and the modal μ-calculus, and study the question whether the tight connection between logic and games can be lifted from the qualitative
logics to their quantitative counterparts. It turns out that, if the quantitative μ-calculus is defined in an appropriate way respecting the duality properties between the logical operators, then its model
checking problem can indeed be characterised by a quantitative variant of parity games. However, these quantitative games
have quite different properties than their classical counterparts, in particular they are, in general, not positionally determined.
The correspondence between the logic and the games goes both ways: the value of a formula on a quantitative transition system
coincides with the value of the associated quantitative game, and conversely, the values of quantitative parity games are
definable in the quantitative μ-calculus. 相似文献
66.
A quality evaluation methodology for health-related websites based on a 2-tuple fuzzy linguistic approach 总被引:1,自引:1,他引:0
J. M. Moreno J. M. Morales del Castillo C. Porcel E. Herrera-Viedma 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2010,14(8):887-897
Nowadays, the patients and physicians use the health-related websites as an important information source and, therefore, it
is critical the quality evaluation of health- related websites. The quality assessment of health-related websites becomes
especially relevant because their use imply the existence of a wide range of threats which can affect people’s health. Additionally,
website quality evaluation can also contribute to maximize the exploitation of invested resources by organizations in the
development of user-perceived quality websites. But there is not yet a clear and unambiguous definition of the concept of
website quality and the debate about quality evaluation on the Web remains open. In this paper, we present a qualitative and
user-oriented methodology for assessing quality of health-related websites based on a 2-tuple fuzzy linguistic approach. To
identify the quality criteria set, a qualitative research has been carried out using the focus groups technique. The measurement
method generates linguistic quality assessments considering the visitors’ judgements with respect to those quality criteria.
The combination of the linguistic judgements is implemented without a loss of information by applying a 2-tuple linguistic
weighted average operator. This methodology means an improvement on quality evaluation of health websites through the commitment
to put users first. 相似文献
67.
Marta Alberti Joaquim Ciurana Ciro A. Rodríguez Tugrul Özel 《Journal of Intelligent Manufacturing》2011,22(2):263-277
Economic globalization, together with heightened market competition and increasingly short product life cycles are motivating
companies to use advanced manufacturing technologies. Use of high speed machining is increasingly widespread; however, as
the technology is relatively new, it lacks a deep-rooted knowledge base which would facilitate implementation. One of the
most frequent problems facing companies wishing to adopt this technology is selecting the most appropriate machine tool for
the product in question and own enterprise characteristics. This paper presents a decision support system for high speed milling
machine tool selection based on machine characteristics and performance tests. Profile machining tests are designed and conducted
in participating machining centers. The decision support system is based on product dimension accuracy, process parameters
such as feed rate and interpolation scheme used by CNC and machine characteristics such as machine accuracy and cost. Experimental
data for process error and cycle operation time are obtained from profile machining tests with different geometrical feature
zones that are often used in manufacturing of discrete parts or die/moulds. All those input parameters have direct impact
on productivity and manufacturing cost. Artificial neural network models are utilized for decision support system with reasonable
prediction capability. 相似文献
68.
José Luis Crespo Marta Zorrilla Pilar Bernardos Eduardo Mora 《The Visual computer》2009,25(4):309-323
The objective of this paper is to present an overall approach to forecasting the future position of the moving objects of
an image sequence after processing the images previous to it. The proposed method makes use of classical techniques such as
optical flow to extract objects’ trajectories and velocities, and autoregressive algorithms to build the predictive model.
Our method can be used in a variety of applications, where videos with stationary cameras are used, moving objects are not
deformed and change their position with time. One of these applications is traffic control, which is used in this paper as
a case study with different meteorological conditions to compare with.
相似文献
Marta Zorrilla (Corresponding author)Email: |
69.
In this paper we introduce a method to compute non-dominated bicriteria shortest pairs, each including two disjoint simple paths. The method is based on an algorithm for ranking pairs of disjoint simple paths by non-decreasing order of cost, that is an adaptation of a path ranking algorithm applied to a network obtained from the original one after a suitable modification of the topology. Each path in this new network corresponds to a pair of paths in the former one. Computational results are presented and analysed for randomly generated networks. 相似文献
70.
In this paper, the performance and durability of hybrid PEM fuel cell vehicles are investigated. To that end, a hybrid predictive controller is proposed to improve battery performance and to avoid fuel cell and battery degradation. Such controller deals with this complex control problem by handling binary and continuous variables, piecewise affine models and constraints. Moreover, the control strategy is to track motor power demand and keep batteries close to a desired battery state of charge which is appropriately chosen to minimize hydrogen consumption. It is important to highlight the consideration of constraints which are directly related to the goals of this paper, such as minimum fuel cell power threshold and time limitation between fuel cell startups and shutdowns. Furthermore, different models have been elaborated and particularized for a vehicle prototype. These models include few innovations such as a reference governor which smooths fuel cell power demand during sharp power profiles, forcing batteries to supply such peaks and resulting a longer fuel cell lifetime. Battery thermal dynamics are also taken into account in these models in order to analyze the effect of battery temperature on its degradation. Finally, this paper studies the feasibility of the real implementation, presenting an explicit formulation as a solution to reduce execution time. This explicit controller exhibits the same performance as the hybrid predictive controller does with a reduced computational effort. All the results have been validated in several simulations. 相似文献