Volume 6, Year 2015, Issue 1, January-March
Abstract: In this paper, we performed recognition of isolated sign language gestures - obtained from Australian Sign Language Database (AUSLAN) – using statistics to reduce dimensionality and neural networks to recognize patterns. We designated a set of 70 signal features to represent each gesture as a feature vector instead of a time series, used principal component analysis (PCA) and independent component analysis (ICA) to reduce dimensionality and indicate the features most relevant for gesture detection. To classify the vectors a feedforward neural network was used. The resulting accuracy of detection ranged between 61 to 87%.
Keywords: principal component analysis (PCA), independent component analysis (ICA), Neural Networks, sign language, automatic recognition
Area: Biomedical Engineering
Abstract: The main subject of the research is a proposition of a luminaire optical system which allows us to illuminate building facades in a more uniform way than it is today in the case when luminaire location is close and asymmetric to the illuminated object. Firstly, the paper introduces and explains the term of floodlighting and presents luminaires that are used in floodlighting. The author casts doubt on floodlighting luminaires quality especially related to luminous intensity distributions. Certain problems arising from illuminating objects by using improper luminaires are presented and discussed. As an attempt to improve the situation, the author shows his innovative concept of the luminaire optical system. Finally, to verify the proposed luminaire optics, the author has made a comparison of his conception with two other luminaires.
Keywords: lighting technology, illumination, floodlighting, luminaires, luminaire design
Area: Power Engineering
Abstract: In recent years in the area of prosthetic treatment, great emphasise was put on leaving a residual dentition inside mouth. In a teeth after endodontic treatment or with broken crown a healthy root is a natural implant that can be used for further reconstruction. Use of posts-and-cores is one of possible methods of widely damaged tooth crowns treatment. There is a lot of different types of prefabricated posts-and-cores. Numerical analysis of the prefabricated post-and-core – tooth system was conducted by the authors. The prefabricated Flexi-Flange post-and-core from the Essential Dental System was selected for the analysis. The scope of the analysis has covered calculation of displacements, strains and stresses in each elements of the analysed system – depending on the applied post material and load applied on the prosthetic crown. The analysis reviled that there is a significant influence of the type of the post material and load on results. It was found that the most unfavourable variant of load is the one with force applied on the labial surface at the angle of 45° to the axis of the tooth. The results of the analysed system provided a valuable guidelines for proper design of its form, geometrical properties, selection of the mechanical properties and the optimal strengthening degree of metallic biomaterial.
Keywords: prefabricated posts, prosthetic reconstruction, finite element analysis
Area: Biomedical Engineering
Abstract: Levitation (from Latin levitas - lightness) is the process in which an object is suspended by a physical force against gravity, in a stable position without solid physical contact. The phenomenon of levitation, caused by magnetic forces is called magnetic levitation. The main advantage of magnetic levitation systems is the elimination of friction, which significantly influences reliability, capability, ecology and safety. The phenomenon of magnetic levitation can be used in Unmanned Aerial Vehicle (UAV) catapult. The article presents the results of experiments performed on the prototype magnetic catapult. Catapult has been designed for small, unmanned aircraft, weighing less than 2 kg. The results show the oscillations of levitating cart of magnetic catapult during simulated and actual take-off and landing procedures.
Keywords: magnetic levitation, superconductors, Meissner effect, and UAV catapult
Area: Mechanics, Automatics and Robotics
Abstract: Chemical admixtures, in addition to cement, sand, gravel and water, are a primary component of concrete. High-range water reducers, also known as superplasticizers, are one of the most important chemical admixtures. The different kinds of superplasticizers possess specific advantages, but also drawbacks. Therefore, new chemical structures for advanced superplasticizers need to be tried. This paper presents new trends in the development of superplasticizers.
Keywords: superplasticizer, admixtures, cement, hyperbranched polymers
Area: Civil Engineering, Urban Planning and Architecture
Abstract: The system of differential-algebraic equations which in a vector form has the representation as the semilinear differential-algebraic equation (DAE) d/dt [Ax(t)]+Bx(t)=f(t,x) with a singular characteristic operator pencil is considered. In particular, underdetermined and overdetermined systems of the differential-algebraic equations correspond to this system. The existence theorem of a global solution of the semilinear differential-algebraic equation is proved. In the case of the overdetermined system, the global solution is unique. The global solution of the underdetermined system is not unique and it depends on the functional parameter determining one of its components. The nonlinear right side of the DAE may not satisfy the constraints of the global Lipschitz condition type. This allows to use the theorem efficiently in real practical applications. Two problems for the models of radio engineering filters with nonlinear elements are researched and the restrictions which ensure the smooth evolution of states throughout an arbitrary large period of time are given. Analysis of the problems have shown that the requirements of the proved theorem are physically feasible. The block representations of the singular characteristic pencil and its components necessary to obtain the main results are considered. The extending solution method in terms of differential inequalities with Lyapunov and La Salle functions and the method of spectral projectors are used in the paper.
Keywords: singular pencil, regular block, differential-algebraic equation, global solution, electric circuit, nonlinear element.
Area: Applied Mathematics
Abstract: The document presents basic problems related to the knowledge discovery in Big Data context. The current growth rate is imposed by the use of different data analysis, adapted for detecting valuable information from many uncorrelated locations. The aggregation of key content generated by various sources is in line with the current trend visible in the world of analytics, exploring the business value dormant in ever-increasing volumes of data. This article describes the architecture of Big Data systems, explains the MapReduce programming paradigm, the Hadoop Distributed File System, Hadoop layers, its architecture, advantages and disadvantages of Hadoop and also clarifies what Big Data is. An integrated approach for Big Data system architecture is illustrated with an example of implementation of NoSQL database and Hadoop Cluster. NoSQL is a technology that is used to store vast databases that are non-relational in nature and that support CRUD (Create, Read, Update and Delete) operations. The results are the basis for the comparison of traditional database systems and large-scale data systems.
Keywords: Big Data, Map Reduce, HDFS, NoSQL Database
Area: Applied Mathematics
Abstract: Effect of replacement of Ga by Sn for two Ni-rich Heusler alloys series: Ni50Mn25+aX25-a (a=0; 2.3; 4.2; 5.8; 7.15; 8.35), with X= Ga, Sn, and its influence on the magnetocaloric properties of the alloys, were studied. The XRD studies revealed that Sn substitution for Ga results in the fact that all alloys exhibit the same austenitic structure, with no evidence of structural transition at room temperature (RT). This was confirmed by magnetic measurements conducted in a low field of 4 kA/m (50 Oe) which showed that the Curie transition temperature are above the RT. The analysis of isothermal magnetic curves allowed the calculation of magnetic entropy change (ΔSM). The highest value of entropy change, |ΔSM| = 2.7 J/kgK in the magnetic field ΔH = 1.5 T, was registered for the Ni50Mn29.20Ga20.80 alloy.
Keywords: magnetocaloric effect, Heusler alloys, magnetic entropy changes
Area: Nanotechnologies and Materials
Abstract: This work studied modification of polypropylene membrane by acrylic acid for the purpose of reducing protein fouling. The surface morphology of the membranes was characterized by FT-IR. BSA static adsorption and tensiometer. Moreover, the hydrodynamic properties for proteins at different pH were tested. Experiments show that the modification of PP membrane prevent protein fouling on membrane syrface. Flows recovery of modified membrane was better than in case of unmodified membrane.
Keywords: polypropylene membrane, acrylic acid, reducing protein fouling
Area: Nanotechnologies and Materials