bluuebunny/crossref_metadata_2025 huggingface dataset:
Lie Symmetry Analysis of Boundary Layer Stagnation-Point Flow and Heat Transfer of Non-Newtonian Power-Law Fluids Over a Nonlinearly Shrinking/Stretching Sheet with Thermal Radiation
Authors: Layek G.C. , Mandal Bidyut , Bhattacharyya Krishnendu , Banerjee Astick
Published: May 2018

A symmetry analysis of steady two-dimensional boundary layer stagnation-point flow and heat transfer of viscous incompressible non-Newtonian power-law fluids over a nonlinearly shrinking/stretching sheet with thermal radiation effect is presented. Lie group of continuous symmetry transformations is employed to the boundary layer flow and heat transfer equations, that gives scaling laws and self-similar equations for a special type of shrinking/stretching velocity (

c

x

1

/

3

$c{x^{1/3}}$

) and free-stream straining velocity (

a

x

1

/

3

$a{x^{1/3}}$

) along the axial direction to the sheet. The self-similar equations are solved numerically using very efficient shooting method. For the above nonlinear velocities, the unique self-similar solution is obtained for straining velocity being always less than the shrinking/stretching velocity for Newtonian and non-Newtonian power-law fluids. The thickness of velocity boundary layer becomes thinner with power-law index for shrinking as well as stretching sheet cases. Also, the thermal boundary layer thickness decreases with increasing values the Prandtl number and the radiation parameter.
Overflows of Elastic Traffic
Authors: Głąbowski Mariusz , Kmiecik Damian
Published: May 2018

This article presents the results of a study on hierarchical multiservice traffic overflow systems. The systems under investigation were composed of a number of primary resources and one alternative resource. Traffic in the considered systems was generated with the assumption that there was a finite number of traffic sources in individual classes. Further assumption was that offered traffic is elastic traffic for which – with an increase of the load of the system – a change in the volume of allocated resources is possible followed by concurrent extension of their service time. The article includes the results that present the blocking probability in the sample elastic traffic overflow systems. The study focuses on a determination of the influence of the traffic intensity, volume of resources, degree of compression, resource with compression (primary resources, alternative resources) and the cardinality of traffic sources on values of the blocking probability in individual call classes and on the number of calls that overflow to the alternative resource.
SDN-Based WAN Optimization: PCE Implementation in Multi-Domain MPLS Networks Supported By BGP-LS
Authors: Rzym Grzegorz , Wajda Krzysztof , Chołda Piotr
Published: May 2018

In order to provide efficient and flexible resource management and path set-up in high-speed MPLS/GMPLS networks, the PCE (Path Computation Element) architecture was proposed by IETF. Implementation of a central module for the path set-up enables network operators to run path establishment operations for applications with explicitly defined objective functions and QoS requirements.

The paper reports on recent research and experimental investigations with PCE-based path computation performed according to the 3- layered traffic engineering (TE) system consisting of: (1) a PCE module equipped with the IBM Cplex LP solver used in the highest layer 3, and (2) a SDN controller in the intermediate layer 2 responsible for transferring path setup requests towards virtual routers in the lowest layer 1.

The presented results show usefulness of the PCE-supporting architecture with an SDN controller and applicability of bandwidth-oriented optimization based on real-time focused constraints (path delay limits). We emphasise that even a simple optimization approach shows the power provided by the SDN, i.e., flexibility of flows. This property is in practice not feasible in classical IP or MPLS networks, that is the usage of flow-based routing provided by network programmability really opens opportunities in network tuning
Multi Criterion Multicast Routing Algorithm Comparison for Large Networks
Authors: Stachowiak Krzysztof
Published: May 2018

QoS enabled multicast routing is known to be of non-polynominal complexity, which leads to the necessity of using heuristic algorithms to find sub-optimal solutions to the problems of this class. The evaluation of such algorithms requires the use of the simulation techniques as the heuristics’ results are of stochastic nature. Because of the problem complexity the simulation times increase significantly in the function of the network size, therefore the results presented in the literature are often limited to only small models. In this article the results of the evaluation of different multicast QoS routing algorithms (further referred to as the Multi-Constrained Minimum Steiner Tree Problem - MCMST) have been presented for a wide range of network sizes reaching thousands of nodes.
The Impact of Selected Parameters on the Performance of Routing Protocols in Wireless Sensor Networks
Authors: Piechowiak Maciej , Zwierzykowski Piotr , Kotlarz Piotr , Żmudziński Piotr
Published: May 2018

The aim of the article was to compare the effectiveness of the selected routing protocols for wireless sensor networks taking into account a number of specific parameters as network troughput, packet error rate and message buffer capacity for different network topologies. The simulation research was conducted in open source OMNeT++ environment. In order to achieve the assumed requirements, four different-sized network topologies were established and AODV and DYMO routing protocols were adapted.
Comparison of Selected Methods for Detecting a Reference Element using Key Points in Static Images
Authors: Kulawik Joanna
Published: May 2018

The article presents a possible way to detect key points. The tests were carried out by the case of detection of a reference object in static images. For comparative purposes, Chris Harris & Mike Stephens [11] and Speeded-Up Robust Features (SURF) detectors [2, 3] were used. The descriptors were built based on the Fast Retina Key point (FREAK) [1, 16] and SURF algorithms [2, 3]. Six different configurations of key point detection methods with the above descriptors were implemented. The obtained results have been presented on exemplary images and in the table. They show that this type of detection of an element of interest can be successful and should be developed.
Analysis of Possibilities to Limitate the WSN Network Emissivity at Assumed Probability of Correct Transmission
Authors: Zabłudowski Łukasz , Marciniak Beata , Bujnowski Sławomir , Lutowski Zbigniew , Maszewski Mirosław
Published: May 2018

The article presents the results of considerations regarding assuring the assumed probability of obtaining a correct transmission while limiting the emissivity of the WSN network. The first part presents the method of selecting the location of the acquisition node and analyzes the impact of the increase in transmission levels on the probability of obtaining a correct transmission. The second part presents and analyzes the method of reduction of the network’s emissivity at the assumed level of correct data transmission, and the end contains a summary and conclusions from the presented considerations.
Analysis of the Possibility of Emission Reduction for Complex WSN Networks by the Implementation of a Larger Number of Acquisition Nodes
Authors: Bujnowski Sławomir , Marciniak Beata , Ledziński Damian , Maszewski Mirosław , Lutowski Zbigniew
Published: May 2018

The article presents the results of simulations conducted on the network which has been implemented in one of the cities with dense urban development. The simulations were conducted to verify how the lowering of the emission (this affected the topology of the network) of the network will affect the network reliability and time of the data collection.
Study of Flow Behavior of Granular Material Inside Cylindrical Silo Using Ultrafast X-Ray Imaging Technique
Authors: Waktola Selam , Bieberle Andre , Barthel Frank , Bieberle Martina , Hampel Uwe , Grudzień Krzysztof , Babout Laurent
Published: May 2018

This paper presents an application of an ultrafast electron beam X-ray CT scanner for investigating the gravitational flow behavior of granulates through cylindrical silo model. The CT scanner allows obtaining crosssectional images of the granular material distribution with a spatial resolution of approximately 1 mm and a time resolution of 2 kHz. In order to conduct a deep analysis of the granular flow concentration changes, two image processing algorithm steps were applied. The first step deals with preprocessing and re-centering stacks of raw images. The second step divides the preprocessed image into several concentric rings and calculates the mean value to study radial concentration changes. Independent analysis of granular concentration in each ring provides useful knowledge to study the silo discharging during mass flow and funnel flow.
Experimental Study of Stochastic Processes, Determining their Characteristics and Conducting Real Experiments on the Operated Bridge
Authors: Sattarova Ulkar
Published: May 2018

The paper describes the process of actual experiment for practical confirmation of the effectiveness of new technologies. New software is proposed for investigating a real stochastic process. Technology and software are designed for fast calculation, analysis of adequate estimates of statistical characteristics, confirming the effectiveness of suggested technology, with high accuracy.
Application of the Fundamental Solution Method to Object Recognition in the Pictures
Authors: Klekiel Tomasz
Published: May 2018

Recognition of objects in pictures and movies requires the use of techniques, such as filtering, segmentation and classification. Image filtering is required to remove all artifacts that hinder the unequivocal identification and sharpen interesting objects. Segmentation refers to finding areas of images respected to individual objects. For the selected areas corresponding to objects in the selected picture, the classification of objects finally gives information about the type of object which orientation is made. This paper presents a method for the classification of objects from drawings as a bitmap using the method of fundamental solutions (MFS). The MFS was tested on the selected bitmap depicting simple geometric shapes. The correlations between errors occurring on the boundary for particular shapes are used for the selection of geometric shape figures. Due to this correlation, it is possible to recognize the shape of the image appearing on the drawing by an analysis consisting of the comparison of recognized points describing the shape of contour to a database containing solutions of boundary value problems for the selected shape. In one way, the comparison of the pattern can determine which shape from database it is most similar to in terms of contour. This article appear that this approach is very simple and clearly. In result, this method can be used to recognition of the objects in the systems of real-time processing.
Fuzzy Logic Based Adaptive Resonance Theory-1 Approach for Offline Signature Verification
Authors: Jain Charu , Singh Priti , Rana Ajay
Published: May 2018

This paper presents the use fuzzy logic with adaptive resonance theory-1 in signature verification. Fuzzy model is capable of stable learning of recognition categories in response to arbitrary sequences of binary input pattern. The work was carried out on two famous available signature corpuses i.e. MCYT (Online Spanish signatures database) and GPDS (Grupo de Procesado Digital de la se?al). Local binary patterns (LBP) and Gray Level Co-occurrence Matrices (GLCM) features were calculated for robust offline signature verification system. Training and verification was done using fuzzy adaptive resonance theory-1(FART-1). The system is trained and verified for different datasets to increase the accuracy of the classifier. The results thus obtained are robust than other existing techniques. The FAR and FRR for the system is 0.74% and 0.83% respectively.
Hazy Underwater Image Enhancement Based on Contrast and Color Improvement Using Fusion Technique
Authors: Singh Ritu , Biswas Mantosh
Published: May 2018

Scattering and absorption of light in water leads to degradation of images captured under the water. This degradation includes diminished colors, low brightness and undistinguishable objects in the image. To improve the quality of such degraded images, we have proposed fusion based underwater image enhancement technique that focuses on improving of the contrast and color of underwater images using contrast stretching and Auto White Balance. Our proposed method is very simple and straightforward that contributes greatly in uplifting the visibility of underwater images.
Sensing Mobile Device Orientation Through ECT Reconstructed Image Processing
Authors: Kucharski Przemysław , Romanowski Andrzej , Grudzień Krzysztof , Babout Laurent , Woźniak Paweł
Published: May 2018

We present TomoTable—a research prototype of a position sensing device hidden inside an ordinary table. While the Human-Computer Interaction (HCI) field has extensively explored possibilities for spatially-aware multi-device interactions, the sensing methods that would enable such systems are still complex and hard to deploy in the wild. TomoTable presents a possibility of easily deployable invisible positional sensing that uses electrical capacitance tomography (ECT). Electrodes are embedded inside the table structure and provide accurate imaging of what is placed on the table. The entire system is invisible to the user. Objects can be identified based on their electrical properties. Our work creates opportunities for in-the-wild studies using multi-device systems. In this paper, we share the technical concept of TomoTable, preliminary insights on its use and perspectives for future studies.
Pneumatic Flow Characterization Using ECT Tomography Images Analysis
Authors: Leszczyńska Agnieszka , Kowalska Aleksandra , Grudzień Krzysztof , Romanowski Andrzej , Sankowski Dominik
Published: May 2018

The control of dense phase pneumatic convening process is not a trivial task. The control of bulk solids flow phenomena requires detailed knowledge about the temporal and spatial changes of material concentration during flow. This paper describes application of electrical capacitance tomography for the characterization of the pneumatic conveying of solids. The level of concentration changes obtained with the aid of tomography imaging and calculated flow velocity allows monitoring flow behaviour during the granular material transport process. The cross-correlation technique applied for image processing as well as the calculated pixels-based flow velocity profile together with the proposed visualisation method of tomography images sequence provide information about flow conditions. The study of flow characterization, based on ECT data, was conducted for measurements gathered with different flow conditions, including flow blockage.
Identification and Assessment of Selected Handwritten Function Graphs Using Least Square Approximation Combined with General Hough Transform
Authors: Bieniecki Wojciech , Stoliński Sebastian
Published: May 2018

The paper provides a comparison of three variants of algorithms for automatic assessment of some examination tasks involving sketching a function graph based on image processing. Three types of functions have been considered: linear, quadratic, and trigonometric. The assumption adopted in the design of the algorithm is to map the way the examiner assesses the solutions and to achieve the evaluation quality close to the one obtained in manual evaluation. In particular, the algorithm should not reject a partly correct solution and also extract the correct solution from other lines, deletions and corrections made by a student. Essential subproblems to solve in our scheme concern image segmentation, object identification and automatic understanding. We consider several techniques based on Hough Transform, least square fitting and nearest neighbor based classification. The most reliable solution is an algorithm combining least square fitting and Hough Transform.
Management of IOT Devices in a Smart Home Through the Application of an Interactive Mirror
Authors: Majchrowicz Michał , Hufnagiel Mateusz
Published: May 2018

Internet of Things (IoT) devices are big part of concept, which is called by electronic producers and many others Smart Home. Authors of this paper have decided to take a look at it and as a result of this analysis propose and implement (in a form of working prototype) a system that could manage different kinds of devices.

The main objective of the project presented in this paper is a device that looks like a mirror and it is known to most people also is an interactive center, a place to obtain information of the devices that surround us and various parameters coming from sensors. Authors have prepared a prototype, that will be the central point of the apartment and will allow users to control all devices connected to this main system. Prototype allows to connect external sensors over GPIO (general purpose input/output) interface or Internet connection. There is also a possibility to add another communication interfaces such as 433MHz radio module, which is very cheap and works great in small areas or bluetooth module.
Application of the Layered Model Management System in an Interactive Map of the University Campus
Authors: Faustryjak Damian , Majchrowicz Michał , Jackowska-Strumiłło Lidia
Published: May 2018

The paper presents a web application for navigation through the university campus, which is based on Global Positioning System GPS and OpenStreetMap. The application has a multilayer structure and multi-labelling support. The proposed solution ensures better management of visual data and more efficient image processing comparing to the other known methods. With the new search system, users can place a lot of information on one layer without losing the legibility of displayed data. All the information that was displayed on the map was grouped and assigned to the appropriate categories.Therefore a map contains a lot of related information that needs to be linked to each other. The system has been divided into modules that ensure the integrity of the displayed things. Presenting so much information at the same time is managed by modules. Their main job is to provide results that is then segregated and grouped. The system presented in this paper was applied for Lodz University of Technology.
The Detection of Internal Fingerprint Image Using Optical Coherence Tomography
Authors: Sekulska-Nalewajko Joanna , Gocławski Jarosław , Sankowski Dominik
Published: May 2018

Recently, optical coherence tomography (OCT) has been tested as a contactless technique helpful for damaged or spoofed fingerprint recovery. Three dimensional OCT images cover the range from the skin surface to papillary region in upper dermis. The proposed method extracts from cross-sections of volumetric images (B-scans) high intensity ridges in both air-epidermis and dermis-epidermis interfaces. The extraction is based on the localisation of two OCT signal peaks corresponding to these edges. The borders are spline smoothed in two orthogonal planes of the image space. The result images are presented and compared with camera views.
Higher-order conditions for strict local Pareto minima for problems with partial order introduced by a polyhedral cone
Authors: Stasiak Aleksandra
Published: May 2018

Using the definitions of μ-th order lower and upper directional derivatives of vector-valued functions, introduced in Rahmo and Studniarski (J. Math. Anal. Appl. 393 (2012), 212–221), we provide some necessary and sufficient conditions for strict local Pareto minimizers of order μ for optimization problems where the partial order is introduced by a pointed polyhedral cone with non-empty interior.
Phenolic-rich extracts ofEurycoma longifoliaandCylicodiscus gabunensisinhibit enzymes responsible for the development of erectile dysfunction and are antioxidants
Authors: Oboh Ganiyu , Adebayo Adeniyi A. , Ademosun Ayokunle O.
Published: May 2018

Background:

Herbs have been used from ages to manage male sexual dysfunction. Hence, this study sought to investigate the effects ofEurycoma longifolia(EL) andCylicodiscus gabunensis(CG) stem bark extracts on some enzymes implicated in erectile dysfunctionin vitro.

Methods:

The extracts were prepared, and their effects on phosphodiesterase-5 (PDE-5), arginase, and angiotensin-1-converting enzyme (ACE) as well as pro-oxidant-induced lipid peroxidation were assessed. Furthermore, phenolic contents were determined, and their components were characterized and quantified using high-performance liquid chromatography with diode array detector (HPLC-DAD).

Results:

The results revealed that the extracts inhibited PDE-5, arginase, and ACE in a concentration-dependent manner. However, IC50values revealed that CG had higher inhibitory potential on PDE-5 (IC50=204.4 μg/mL), arginase (IC50=39.01 μg/mL), and ACE (IC50=48.81 μg/mL) than EL. In addition, the extracts inhibited pro-oxidant-induced lipid peroxidation in penile tissue homogenate. HPLC-DAD analysis showed that CG is richer in phenolic compounds than EL, and this could be responsible for higher biological activities observed in CG than EL.

Conclusions:

Hence, the observed antioxidant property and inhibitory action of CG and EL on enzymes relevant to erectile dysfunctionin vitrocould be part of possible mechanisms underlying their involvement in traditional medicine for the management of male sexual dysfunction.
Non-equilibrium Thermodynamics of Fast Traveling Waves in a Catalytic Fixed Bed. Emergence of Near-equilibrium Spatiotemporal Dissipative Structure
Authors: Gerasev Alexander P.
Published: May 2018

This work presents the results of the mathematical modeling of the fast traveling wave propagation phenomenon in the fixed-bed catalytic reactors according to a simple (basic) mathematical model with a reversible reaction. Qualitative and quantitative research is used to study the behavior of separatrices’ trajectories of the system’s non-linear ordinary differential equations. Special attention has been paid to the non-equilibrium thermodynamic methods. The entropy balance equation is constructed and analyzed under the assumption of the simple mathematical model of physical and chemical processes. The influence of key physical and chemical parameters on the fast traveling wave properties is studied. The phenomenon of fast traveling wave propagation in the fixed-bed catalytic reactors provides a vivid example of a spatiotemporal dissipative structure in active heterogeneous medium. These dissipative structures are shown to exist near the thermodynamic equilibrium.
Faith and Pedagogy: Intersections of Asian American Teachers’ Identities and Practice
Authors: Chow Candace J.
Published: May 2018

This article explores the role that teachers’ religious identities play in the classroom, particularly as they relate to understandings of race and equity. Employing an intersectional framework, I use interview data to examine how two Asian American teachers, who emphasize how important their Christian identities are to their lives and to their classroom practice, enact identity and pedagogy. Findings suggest that Christian teachers see teaching as an act of Christian service, that both faith and racial identities play roles in shaping culturally relevant pedagogy, and that teachers’ faith identities are integral to how they view themselves as individuals and as teachers.
Small-large subgroups of the reals
Authors: Rosłanowski Andrzej , Shelah Saharon
Published: May 2018

We are interested in subgroups of the reals that are small in one and large in another sense. We prove that, in ZFC, there exists a non-meager Lebesgue null subgroup of ℝ, while it is consistent that there there is no non-null meager subgroup of ℝ.
Structural properties of algebras of S-probabilities
Authors: Dorninger Dietmar , Länger Helmut
Published: May 2018

Let S be a set of states of a physical system. The probabilities p(s) of the occurrence of an event when the system is in different states s ∈ S define a function from S to [0, 1] called a numerical event or, more precisely, an S-probability. A set of S-probabilities comprising the constant functions 0 and 1 which is structured by means of the addition and order of real functions in such a way that an orthomodular partially ordered set arises is called an algebra of S-probabilities, a structure significant as a quantum-logic with a full set of states. The main goal of this paper is to describe algebraic properties of algebras of S-probabilities through operations with real functions. In particular, we describe lattice characteristics and characterize Boolean features. Moreover, representations by sets are considered and pertinent examples provided.
On Fibonomial sums identities with special sign functions: analytically q-calculus approach
Authors: Kiliç Emrah , Akkus Ilker
Published: May 2018

Recently Marques and Trojovsky [On some new identities for the Fibonomial coefficients, Math. Slovaca 64 (2014), 809–818] presented interesting two sum identities including the Fibonomial coefficients and Fibonacci numbers. These sums are unusual as they include a rare sign function and their upper bounds are odd. In this paper, we give generalizations of these sums including the Gaussian q-binomial coefficients. We also derive analogue q-binomial sums whose upper bounds are even. Finally we give q-binomial sums formulæ whose weighted functions are different from the earlier ones. To prove the claimed results, we analytically use q-calculus.
On the proximity of multiplicative functions to the number of distinct prime factors function
Authors: Koninck Jean-Marie De , Doyon Nicolas , Laniel François
Published: May 2018

Given an additive function f and a multiplicative function g, let E(f, g;x) = #{n ≤ x: f(n) = g(n)}. We study the size of E(ω,g;x) and E(Ω,g;x), where ω(n) stands for the number of distinct prime factors of n and Ω(n) stands for the number of prime factors of n counting multiplicity. In particular, we show that E(ω,g;x) and E(Ω,g;x) are

O

x

log
log
⁡
x

$\begin{array}{}
\displaystyle
O\left(\frac{x}{\sqrt{\log\log x}}\right)
\end{array}$

for any integer valued multiplicative function g. This improves an earlier result of De Koninck, Doyon and Letendre.
Truncated euler polynomials
Authors: Komatsu Takao , Pita-Ruiz Claudio
Published: May 2018

We define a truncated Euler polynomial E

m,n
(x) as a generalization of the classical Euler polynomial En
(x). In this paper we give its some properties and relations with the hypergeometric Bernoulli polynomial.
Growth series of crossed and two-sided crossed products of cyclic groups
Authors: Karpuz Eylem Güzel , Çetinalp Esra Kirmizi
Published: May 2018

We recall that the two-sided crossed product of finite cyclic groups is actually a generalization of the crossed product construction of the same type of groups (cf. [10]). In this paper, by considering the crossed and two-sided crossed products obtained from both finite and infinite cyclic groups, we first present the complete rewriting systems and normal forms of elements over crossed products. (We should note that the complete rewriting systems and normal forms of elements over two-sided crossed products have been recently defined in [10]). In the crossed product case, we will consider their presentations that were given in [2]. As a next step, by using the normal forms of elements of these two products, we calculate the growth series of the crossed product of different combinations of finite and infinite cyclic groups as well as the growth series of two-sided crossed product of finite cyclic groups.
Uniqueness properties of meromorphic functions in the light of three shared sets
Authors: Banerjee Abhijit , Mallick Sanjay
Published: May 2018

We use the notion of weighted sharing of sets to improve a number of results in the uniqueness theory of meromorphic functions sharing three sets. We have also presented a new idea in the formation of one of the range sets in connection with the three shared set problems, which ultimately yields a better result than many existing result in some sense.
A new family of analytic functions defined by means of Rodrigues type formula
Authors: Aktaş Rabia , Altin Abdullah , Taşdelen Fatma
Published: May 2018

In this article, a class of analytic functions is investigated and their some properties are established. Several recurrence relations and various classes of bilinear and bilateral generating functions for these analytic functions are also derived. Examples of some members belonging to this family of analytic functions are given and differential equations satisfied by these functions are also obtained.
Perturbation analysis of a nonlinear equation arising in the Schaefer-Schwartz model of interest rates
Authors: Stehlíková Beáta
Published: May 2018

We deal with the interest rate model proposed by Schaefer and Schwartz, which models the long rate and the spread, defined as the difference between the short and the long rates. The approximate analytical formula for the bond prices suggested by the authors requires a computation of a certain constant, defined via a nonlinear equation and an integral of a solution to a system of ordinary differential equations. A quantity entering the nonlinear equation is expressed in a closed form, but it contains infinite sums and evaluations of special functions. In this paper we use perturbation methods to compute the constant of interest as an asymptotic serie with coefficients given in closed form and expressed using elementary functions. A quick computation of the bond prices, which our approach allows, is essential for example in calibration of the model by means of fitting the observed yields, where the theoretical bond prices need to be recalculated for every observed date and maturity, as well as every combination of parameters considered. The first step of our derivation is identification of a small parameter in the problem, since it is not immediately clear. We verify our choice by numerical experiments using the values of parameters from the literature.
On the solutions of a second-order difference equation in terms of generalized Padovan sequences
Authors: Halim Yacine , Rabago Julius Fergy T.
Published: May 2018

This paper deals with the solution, stability character and asymptotic behavior of the rational difference equation

x

n
+
1

=

α

x

n
−
1

+
β

γ

x

n

x

n
−
1

,

n
∈

N

0

,

$$\begin{array}{}
\displaystyle
x_{n+1}=\frac{\alpha x_{n-1}+\beta}{ \gamma x_{n}x_{n-1}},\qquad n
\in \mathbb{N}_{0},
\end{array}$$

where ℕ0 = ℕ ∪ {0}, α, β, γ ∈ ℝ+, and the initial conditions x
–1 and x
0 are non zero real numbers such that their solutions are associated to generalized Padovan numbers. Also, we investigate the two-dimensional case of the this equation given by

x

n
+
1

=

α

x

n
−
1

+
β

γ

y
n

x

n
−
1

,

y

n
+
1

=

α

y

n
−
1

+
β

γ

x
n

y

n
−
1

,

n
∈

N

0

.

$$\begin{array}{}
\displaystyle
x_{n+1} = \frac{\alpha x_{n-1} + \beta}{\gamma y_n x_{n-1}}, \qquad y_{n+1} = \frac{\alpha y_{n-1} +\beta}{\gamma x_n y_{n-1}} ,\qquad n\in \mathbb{N}_0.
\end{array}$$
Fixed points in C
∗-algebra valued b-metric spaces endowed with a graph
Authors: Mohanta Sushanta Kumar
Published: May 2018

We discuss the existence and uniqueness of fixed points for a self-mapping defined on a C
∗-algebra valued b-metric space endowed with a graph. Our results extend and supplement several recent results in the literature. Some examples are provided to illustrate our results. Finally, as an application of G-contraction mapping theorem, existence of unique solution for a type of operator equation is given.
A general fixed point theorem for two pairs of mappings satisfying a mixed implicit relation
Authors: Popa Valeriu , Patriciu Alina-Mihaela
Published: May 2018

In this paper a general fixed point theorem for mappings with a new type of common limit range property satisfying a mixed implicit relation is proved. In the last part of the paper, as application, some fixed point results for mappings satisfying contractive conditions of integral type and for φ-contractive mappings are obtained.
Productively sequential spaces
Authors: Dolecki Szymon , Mynard Frédéric
Published: May 2018

We characterize productively sequential spaces, that is, spaces whose product with every strongly sequential space is sequential, equivalently strongly sequential. It turns out that a regular topology is productively sequential if and only if it is sequential and bi-quasi-k.
Euler classes of vector bundles over iterated suspensions of real projective spaces
Authors: Naolekar Aniruddha C. , Thakur Ajay Singh
Published: May 2018

We show that when k ≠ 2, 4, 8 the Euler class of any vector bundle over Σ
k
ℝℙ
m
is zero if the rank of the bundle is not m + k, provided that m ≠ 3 when k = 6. If k = 2, 4, 8 we show that the Euler class of any vector bundle over Σ
k
ℝℙ
m
is zero whenever the rank of the bundle is not kr + k, provided that m ≠ 6, 7 when k = 2, where r is the largest integer such that kr ≤ m.
Restricted injective dimensions over local homomorphisms
Authors: Wu Dejun , Kong Fangdi
Published: May 2018

In this paper, we study the small restricted injective dimension over local ring homomorphisms. Some of known results are generalized. For example, the Bass formula for the small restricted injective dimension of complexes is extended.
Manipulating line waves in flat graphene for agile terahertz applications
Authors: Bisharat Dia’aaldin J. , Sievenpiper Daniel F.
Published: May 2018

Reducing open waveguides enabled by surface waves, such as surface plasmon polaritons, to a one-dimensional line is attractive due to the potentially enhanced control over light confinement and transport. This was recently shown to be possible by simply interfacing two co-planar surfaces with complementary surface impedances, which support transverse-magnetic and transverse-electric modes, respectively. Attractively, the resultant “line wave” at the interface line features singular field enhancement and robust direction-dependent polarizations. Current implementations, however, are limited to microwave frequencies and have fixed functionality due to the lack of dynamic control. In this article, we examine the potential of using gate-tunable graphene sheets for supporting line waves in the terahertz regime and propose an adequate graphene-metasurface configuration for operation at room temperature and low voltage conditions. In addition, we show the occurrence of quasi-line wave under certain conditions of non-complementary boundaries and qualify the degradation in line wave confinement due to dissipation losses. Furthermore, we show the possibility to alter the orientation of the line wave’s spin angular momentum on demand unlike conventional surface waves. Our results on active manipulation of electromagnetic line waves in graphene could be useful for various applications including reconfigurable integrated circuits, modulation, sensing and signal processes.
Comprehensive studies of the Ag+ effect on borosilicate glass ceramics containing Ag nanoparticles and Er-doped hexagonal NaYF4 nanocrystals: morphology, structure, and 2.7 μm emission
Authors: Liu Qunhuo , Tian Ying , Tang Wenhua , Jing Xufeng , Zhang Junjie , Xu Shiqing
Published: May 2018

In this work, we have performed a comprehensive investigation of the Ag+ concentration effect on the morphological, thermal, structural, and mid-infrared emission properties of novel oxyfluoride borosilicate glasses and glass ceramics containing both Ag nanoparticles and erbium-doped hexagonal NaYF4 nanocrystals. The effect of Ag+ ions on the glass forming and crystallization processes was discussed in detail by glass structural analysis. It was found that the Ag+ concentration can affect the distribution of Na+ ion and bridge oxygen in boron-rich and silicon-rich phases, which induced the transformation between BO3 triangles and BO4 tetrahedra during crystallization process. In addition, there was a turning point when the doped Ag+ ion concentration reached its solubility in the borosilicate glass. Furthermore, the enhancement of the 2.7 μm emission and the reduction of the lifetime of the 4I13/2 level were observed both in glasses and in glass ceramics, and its origin was revealed by qualitative and quantitative analyses of the Er3+-Ag nanoparticles (localized electric field enhancement) and Er3+-Er3+ (nonradiative resonance energy transfer) interactions within glasses and glass ceramics. Moreover, the high lifetime of the 4I11/2 level (2.12 ms) and the peak emission cross section in 2.7 μm (6.8×10−21 cm2) suggested that the prepared glass ceramics have promising mid-infrared laser applications.
From the first rigorous proof of the Circular Law in 1984 to the Circular Law for block random matrices under the generalized Lindeberg condition
Authors: Girko Vyacheslav L.
Published: May 2018

The Circular Law under Lindeberg’s condition for the independent blocks of random matrices having zero expectations and double stochastic matrix of covariances of their array is proven.
Bandbereichswahl und Materialanteilsschätzung mithilfe von Spektralfiltern
Authors: Krippner Wolfgang , Puente León Fernando
Published: May 2018

Hyperspektralbilder liefern neben räumlicher auch spektrale Information. Dadurch ist es möglich, zu jedem Pixel solcher Bilder qualitative und quantitative Analysen, wie beispielsweise die Bestimmung einzelner Materialanteile, über die aufgezeichnete Szene durchzuführen. Die Mehrzahl der dazu verwendeten Methoden besitzt einen hohen Rechenzeitbedarf und basiert auf einem vollständig aufgezeichneten Hyperspektralbild, zu dessen Aufnahme kostspielige Hardware und hoher Speicherbedarf notwendig sind. Um diese Nachteile zu beseitigen, wird in diesem Beitrag ein Ansatz mit optischer Spektralfilterung verfolgt. Anstelle eines Hyperspektralbilds werden durch spektrale Filterungen des von der Szene reflektierten Lichts nur noch einige wenige Intensitätsbilder aufgenommen. Jedes dieser Bilder enthält Information in Abhängigkeit des entworfenen Spektralfilters. So können mithilfe der spektralen Filterung Materialanteile unmittelbar ortsaufgelöst aufgezeichnet werden. Die Genauigkeit der geschätzten Materialanteile ist stark von dem angenommen Mischmodell der Reinstoffe abhängig. Für präzisere Schätzungen wird deshalb mit weiteren Spektralfiltern eine Bandbereichsauswahl vor der Materialanteilsschätzung getroffen. Die hierbei aufgezeichneten Intensitätsbilder werden verwendet, um einzelne Bandbereiche nach der Abweichung von dem angenommenen Mischmodell zu bewerten. Da die Bandbereichsauswahl ebenso optisch erfolgen kann, bleiben der Rechenaufwand und Speicherbedarf gering, während genauere Materialanteilsschätzungen erzielt werden.
Research assistants’ experiences of co-creating partnership learning communities for learning and teaching in higher education
Authors: Sterenberg Gladys , O'Connor Kevin , Donnelly Ashlyn , Drader Ranee
Published: May 2018

Calls for enhancing student engagement in higher education have offered strong arguments for student-faculty partnerships in teaching and learning. Drawing on a conceptual model of partnership learning communities (PLC), we investigate the experiences of two undergraduate research assistants (co-authors of this paper) who participated in a PLC within a Scholarship of Teaching and Learning research study. In this paper, we use data from transcripts of four research conversations occurring over a three-year period. Evidence of research assistants’ experiences was co-analyzed using benefits and challenges identified in the literature. Our findings reveal that our PLC helped these research assistants develop student agency and provided opportunities for reflection on learning. We conclude that participating in our PLC helped the two research assistants develop deeper pedagogical relationships amongst themselves and with the faculty partners. Moreover, our study directly contributed to the development of our bachelor of education degree program while ensuring students were partners in that process.
Students as partners in learning and teaching: The benefits of co-creation of the curriculum
Authors: Lubicz-Nawrocka Tanya Michelle
Published: May 2018

This research explores the benefits of co-creation of the curriculum, which is seen as one form of student-staff partnership in learning and teaching in which each partner has a voice and a stake in curriculum development. This qualitative research analyses participants’ perceptions of co-creation of the curriculum in the Scottish higher-education sector. Initial findings show that some staff and students participating in co-creation of the curriculum perceive it to benefit them by (a) fostering the development of shared responsibility, respect, and trust; (b) creating the conditions for partners to learn from each other within a collaborative learning community; and (c) enhancing individuals’ satisfaction and personal development within higher education. Using Barnett’s conceptualisation of supercomplexity and Baxter Magolda’s three-pronged view of self-authorship, the author suggests that critical and democratic engagement in co-creation of the curriculum can develop the self-authorship of both students and staff members, including their cognitive, interpersonal, and intrapersonal abilities which help them adapt to an ever-changing, supercomplex world.
Learning "betwixt and between": Opportunities and challenges for student-driven partnership
Authors: Barrineau Susanna , Anderson Lakin
Published: May 2018

This paper analyses students’ experiences of a partnership learning community in which students take on an unusual amount of power over decision-making in the design and implementation of interdisciplinary education. Student-driven contexts are largely absent in literature on partnership in higher education, which has thus far been based on empirical study of institutional contexts in which faculty have more power than students. This reveals a gap in knowledge about arrangements in which students have more control over decision-making than faculty. Drawing from in-depth interviews with student course coordinators, and using the concepts of roles and liminality, we analyse how course coordinators perceive their challenging and often ambiguous roles in which they renegotiate their relationships to staff, students, and the university itself. We then identify some challenges and opportunities for partnership within this context.
“I feel like some students are better connected”: Students’ perspectives on applying for extracurricular partnership opportunities
Authors: Marquis Elizabeth , Jayaratnam Ajitha , Mishra Anamika , Rybkina Ksenia
Published: May 2018

While existing research has discussed the need for student-faculty partnership opportunities to be inclusive and accessible, attention to students’ motivations for participating in extracurricular partnership activities, and to their sense of the relative accessibility of such opportunities, has been limited. The present study, designed and conducted by students and faculty working in partnership, aimed to address this gap in the literature by exploring how students at a Canadian research-intensive university with a centrally-supported Student Partners Program perceive extracurricular partnership opportunities and the process of applying for them. Drawing from survey and focus group data, we describe students’ motivations for taking part in student-staff partnership initiatives and their sense of the program features that enable and constrain students’ participation. Implications of these findings for practitioners and researchers interested in Students as Partners are discussed.
Three heads are better than one: Students, faculty, and educational developers as co-developers of Science curriculum
Authors: Goff Lori , Knorr Kris
Published: May 2018

Curriculum planning should be a shared responsibility that involves students. To encourage higher education students to actively participate in their own education, we believe in the idea of engaging students as partners in learning and teaching. We have developed an Applied Curriculum Design in Science course at McMaster University that is aimed at engaging students as co-creators of curriculum. In this course, upper-year students form partnerships with faculty and educational developers and work in groups to co-create learning modules that become key components of a foundational Science course offered to first-year students. We present a scholarly exploration of our rationale for the course, the implementation and critical analysis of the initiative, and ideas for sustaining the co-created pedagogical approaches and continued student engagement in co-creating components of the curriculum.
‘Locations of Possibility’: Critical perspectives on partnership
Authors: Cates Rhiannon M. , Madigan Mariah R. , Reitenauer Vicki L.
Published: May 2018

This article offers critical perspectives on collaborative partnerships and feminist teaching that revise paradigms of power, prioritize student agency, enrich curriculum and scholarship, and sustain empowered communities of learning that challenge institutional compartmentalization. The authors reflect on how co-created curriculum can catalyze new professional partnerships that in turn contribute to refreshed learning experiences and communities. This article presents evidence of how a partnership orientation effectively encompasses an ethic and practice of feminist teaching, posits a framework of feminist pedagogy and praxis into the discourse of partnership, and exemplifies possibilities of these practices as important steps towards a (re)vision of liberatory learning.
Effect of Energy Drink Consumption on Power and Velocity of Selected Sport Performance Activities
Authors: Jacobson Bert H. , Hester Garrett M. , Palmer Ty B. , Williams Kathryn , Pope Zachary K. , Sellers John H. , Conchola Eric C. , Woolsey Conrad , Estrada Carlos
Published: May 2018

Jacobson, BH, Hester, GM, Palmer, TB, Williams, K, Pope, ZK, Sellers, JH, Conchola, EC, Woolsey, C, and Estrada, C. Effect of energy drink consumption on power and velocity of selected sport performance activities. J Strength Cond Res 32(6): 1613–1618, 2018—Energy drinks (ED) comprise a multibillion dollar market focused on younger, active, and competitive individuals. Marketing includes claims of improved alertness and performance. The purpose of this study was to assess power (W) and velocity (m·s−1) of a simulated, isolated forehand stroke (FHS), and a countermovement vertical jump (CVJ) before and after ingestion of a commercially available energy shot (ES) or a placebo (PL). Healthy college-aged men and women (N = 36) volunteers were randomly placed in the ES or PL. Before and 30 minutes after ingesting either the ES or PL, participants performed 3 FHSs and CVJs. Power and velocity of each performance was measured using a linear velocity transducer and the highest value for each measure was used for subsequent analysis. The ES group demonstrated a significant (p = 0.05) increase in velocity and W for the FHS, but not for the CVJ. All measures remained unchanged in the PL group for both, the FHS and CVJ. Females demonstrated a significant increase in velocity over males in FHS, but not in CVJ. It was concluded that while the dose of stimulants in the ES was adequate to improve performance of smaller muscle groups, it may not have been sufficient to affect the larger muscle groups of the lower legs which contribute to the CVJ. While the ES used in the present study contained a caffeine dosage within the NCAA limit and did improve performance for the upper body, it must be noted that there are health risks associated with ED consumption.