bluuebunny/crossref_metadata_2025 huggingface dataset:
Causes and consequences of invertebrate drift in running waters: from individuals to populations and trophic fluxes
Authors: Naman Sean M. , Rosenfeld Jordan S. , Richardson John S.
Published: February 2016

Invertebrate drift, the downstream transport of aquatic invertebrates, is a fundamental ecological process in streams with important management implications for drift-feeding fishes. Despite long-standing interest, many aspects of drift remain poorly understood mechanistically, thereby limiting broader food web applications (e.g., bioenergetics-based habitat models for fish). Here, we review and synthesize drift-related processes, focusing on their underlying causes, consequences for invertebrate populations and broader trophic dynamics, and recent advances in predictive modelling of drift. Improving predictive models requires further resolving the environmental contexts where drift is driven by hydraulics (passive drift) versus behaviour (active drift). We posit this can be qualitatively inferred by hydraulic conditions, diurnal periodicity, and taxa-specific traits. For invertebrate populations, while the paradox of population persistence in the context of downstream loss has been generally resolved with theory, there are still many unanswered questions surrounding the consequences of drift for population dynamics. In a food web context, there is a need to better understand drift-foraging consumer–resource dynamics and to improve modelling of drift fluxes to more realistically assess habitat capacity for drift-feeding fishes.
Nebivolol has a beneficial effect in monocrotaline-induced pulmonary hypertension
Authors: Pankey Edward A. , Edward Justin A. , Swan Kevin W. , Bourgeois Camille R.T. , Bartow Matthew J. , Yoo Daniel , Peak Taylor A. , Song Bryant M. , Chan Ryan A. , Murthy Subramanyam N. , Prieto Minolfa C. , Giles Thomas D. , Kadowitz Philip J.
Published: February 2016

Pulmonary hypertension is a rare disorder that, without treatment, is progressive and fatal within 3–4 years. Current treatment involves a diverse group of drugs that target the pulmonary vascular bed. In addition, strategies that increase nitric oxide (NO) formation have a beneficial effect in rodents and patients. Nebivolol, a selective β1 adrenergic receptor-blocking agent reported to increase NO production and stimulate β3 receptors, has vasodilator properties suggesting that it may be beneficial in the treatment of pulmonary hypertension. The present study was undertaken to determine whether nebivolol has a beneficial effect in monocrotaline-induced (60 mg/kg) pulmonary hypertension in the rat. These results show that nebivolol treatment (10 mg/kg, once or twice daily) attenuates pulmonary hypertension, reduces right ventricular hypertrophy, and improves pulmonary artery remodeling in monocrotaline-induced pulmonary hypertension. This study demonstrates the presence of β3 adrenergic receptor immunoreactivity in pulmonary arteries and airways and that nebivolol has pulmonary vasodilator activity. Studies with β3 receptor agonists (mirabegron, BRL 37344) and antagonists suggest that β3 receptor-mediated decreases in systemic arterial pressure occur independent of NO release. Our results suggest that nebivolol, a selective vasodilating β1 receptor antagonist that stimulates β3 adrenergic receptors and induces vasodilation by increasing NO production, may be beneficial in treating pulmonary hypertensive disorders.
Toxicity testing and drug screening using iPSC-derived hepatocytes, cardiomyocytes, and neural cells
Authors: Csöbönyeiová Mária , Polák Štefan , Danišovič L’uboš
Published: February 2016

Unexpected toxicity in areas such as cardiotoxicity, hepatotoxicity, and neurotoxicity is a serious complication of clinical therapy and one of the key causes for failure of promising drug candidates in development. Animal studies have been widely used for toxicology research to provide preclinical security evaluation of various therapeutic agents under development. Species differences in drug penetration of the blood–brain barrier, drug metabolism, and related toxicity contribute to failure of drug trials from animal models to human. The existing system for drug discovery has relied on immortalized cell lines, animal models of human disease, and clinical trials in humans. Moreover, drug candidates that are passed as being safe in the preclinical stage often show toxic effects during the clinical stage. Only around 16% drugs are approved for human use. Research on induced pluripotent stem cells (iPSCs) promises to enhance drug discovery and development by providing simple, reproducible, and economically effective tools for drug toxicity screening under development and, on the other hand, for studying the disease mechanism and pathways. In this review, we provide an overview of basic information about iPSCs, and discuss efforts aimed at the use of iPSC-derived hepatocytes, cardiomyocytes, and neural cells in drug discovery and toxicity testing.
The spacetime models with dust matter that admit separation of variables in Hamilton–Jacobi equations of a test particle
Authors: Osetrin Konstantin , Filippov Altair , Osetrin Evgeny
Published: February 2016

The characteristics of dust matter in spacetime models, admitting the existence of privilege coordinate systems are given, where the single-particle Hamilton–Jacobi equation can be integrated by the method of complete separation of variables. The resulting functional form of the 4-velocity field and energy density of matter for all types of spaces under consideration is presented.
A systematic study of proton, alpha and cluster decays in Rhenium isotopes using the effective liquid drop model
Authors: Joseph Deepthy Maria , Ashok Nithu , Joseph Antony
Published: February 2016

Employing the effective liquid drop model (ELDM), half-lives of proton and alpha decays and probable cluster decays are computed and analyzed for different proton-rich and neutron-rich isotopes of Rhenium. The investigation fortifies the phenomenon of cluster radioactivity (CR) in rare earth nuclei and also affirms the pivotal role played by neutron magicity in cluster decays. ELDM data is compared with that of universal decay law (UDL) model and found to be more efficient than the latter one. Apparently, cluster emissions slacken as the neutron number of daughter nucleus goes up and the linear nature of Geiger–Nuttall (G–N) plots stays unaltered even if the surface potential is incorporated.
Semiclassical approach for the evaporating black hole revisited
Authors: Gim Yongwan , Kim Wontae
Published: February 2016

A recent calculation shows that the observed energy density in the Unruh state at the future event horizon as seen by a freely falling observer is finite if the observer is released from rest at any positive distance outside the horizon; however, it is getting larger and larger so that it is negatively divergent at the horizon in the limit that the observer starts falling from rest at the horizon, which corresponds to the infinite boost with respect to the freely falling observer at a finite distance from the horizon. In order to resolve some conflicts between the recent calculation and the conventional ones in the well-known literatures, the calculation of the free-fall energy density is revisited and some differences are pointed out.
Structure of Xb from line shape analysis
Authors: Ma Yue , Chen Guo-Ying
Published: February 2016

We study the production line shape of [Formula: see text] near threshold, where the [Formula: see text] pair comes from the resonance [Formula: see text]. Our study shows that the line shape depends sensitively on the binding energy and the probability of finding an elementary state in the physical bound state. Both of the two parameters are crucial to identify the structure of [Formula: see text]. Therefore, the line shape measurement can shed light on the structure of [Formula: see text].
Weak-field general relativistic dynamics and the Newtonian limit
Authors: Cooperstock F. I.
Published: February 2016

We show that the generally held view that the gravity of weak-field nonrelativistic-velocity sources being invariably almost equivalent to Newtonian gravity (NG) (the “Newtonian limit” approach) is in some instances misleading and in other cases incorrect. A particularly transparent example is provided by comparing the Newtonian and general relativistic analyses of a simple variant of van Stockum’s infinite rotating dust cylinder. We show that some very recent criticisms of our work that had been motivated by the Newtonian limit approach were incorrect and note that no specific errors in our work were found in the critique. In the process, we underline some problems that arise from inappropriate coordinate transformations. As further support for our methodology, we note that our weak-field general relativistic treatment of a model galaxy was vindicated recently by the observations of Xu et al. regarding our prediction that the Milky Way was 19–21 kpc in radius as opposed to the commonly held view that the radius was 15 kpc.
Unitarization and causalization of nonlocal quantum field theories by classicalization
Authors: Addazi Andrea
Published: February 2016

We suggest that classicalization can cure nonlocal quantum field theories from acausal divergences in scattering amplitudes, restoring unitarity and causality. In particular, in “trans-nonlocal” limit, the formation of nonperturbative classical configurations, called classicalons, in scatterings like [Formula: see text], can avoid typical acausal divergences.
The combined effect of attraction and orientation zones in 2D flocking models
Authors: Iliass Tarras , Cambui Dorilson
Published: February 2016

In nature, many animal groups, such as fish schools or bird flocks, clearly display structural order and appear to move as a single coherent entity. In order to understand the complex motion of these systems, we study the Vicsek model of self-propelled particles (SPP) which is an important tool to investigate the behavior of collective motion of live organisms. This model reproduces the biological behavior patterns in the two-dimensional (2D) space. Within the framework of this model, the particles move with the same absolute velocity and interact locally in the zone of orientation by trying to align their direction with that of the neighbors. In this paper, we model the collective movement of SPP using an agent-based model which follows biologically motivated behavioral rules, by adding a second region called the attraction zone, where each particles move towards each other avoiding being isolated. Our main goal is to present a detailed numerical study on the effect of the zone of attraction on the kinetic phase transition of our system. In our study, the consideration of this zone seems to play an important role in the cohesion. Consequently, in the directional orientation, the zone that we added forms the compact particle group. In our simulation, we show clearly that the model proposed here can produce two collective behavior patterns: torus and dynamic parallel group. Implications of these findings are discussed.
Using priority growth orientation of crystallite of the Monte Carlo method to study the process of crystal nucleation and growth in liquid phase
Authors: Shi Yu , Chen Manjiao , Huang Jiankang , Gu Yufen , Fan Ding
Published: February 2016

The technique of “crystallite growth preferred orientation” was presented based on the Monte Carlo (MC) simulations of grain growth, and its factor was used to establish a lattice coordinate tracking method. The nucleation and growth of crystal from the liquid phase throughout the whole simulation were examined. Changes in solid fraction and crystallite size were counted via simulation by lattice tracking. Results showed that the established model could properly reflect crystallite nucleation and growth. The model was also determined capable of accurately estimating the number of solid phase fraction and achieving change in crystallite size by the lattice tracking method. The change in solid fraction and MC step (MCS) satisfied the [Formula: see text] curve during simulation. The crystallite growth index was 0.477, which was relatively close to the theoretical value of 0.5.
Enhancing the coupling of a two-coil system using a superscatterer
Authors: Yao Chen , Zhang Yingyi , Ma Dianguang , Tang Houjun
Published: February 2016

In an example scenario of magnetic energy harvesting, a spherical superscatterer is introduced to enhance coupling in a two-coil system. Although a three-dimensional (3D) model is preferred to fully model behavior in this example, to reduce computational complexity, an extension of transformation optics (TO) is proposed to reduce a 3D model to a two-dimensional (2D) axisymmetric model. The simulation results show details of a quasi-3D model of the superscatterer coupling enhancement of a two-coil system.
Study of divalent elements (Mg, Sr and Ba)-doped LaMnO3 nano-manganites
Authors: Ramay Shahid Mahmood , Mahmood Asif , Atiq Shahid , AlHazaa A. N.
Published: February 2016

Doping of group-II divalent cations in LaMnO3 can produce advanced multi-functionalities in these nano-manganite materials according to recent theoretical approaches. An experimental investigation of Mg, Sr and Ba-doped LaMnO3 nano-structures has been made by synthesizing these compositions with fuel agent assistive sol–gel auto-combustion technique. Detailed structural studies were carried out for crystal structure, lattice parameters, crystallite size, density and strain in structure using the data obtained from X-ray diffraction (XRD). Structural parameters were largely affected and significantly varied in all compositions due to doping of group-II elements with different sized ionic radii. Morphological and compositional analyzes were carried out using scanning electron microscopy and energy dispersive X-ray spectroscopy, respectively. Electrical and magnetic properties were explored using four-point probe and physical property measurement setups and observed a significant change in various compositions. The substitution of group-II atoms with different sized ionic radii on the regular sites in structure provides a distinctive behavior in various properties.
Contribution of the basis-dependent adiabatic geometric phase to noncyclic evolution
Authors: Thomaz M. T.
Published: February 2016

The geometric phase acquired by the vector states under an adiabatic evolution along a noncyclic path can be calculated correctly in any instantaneous basis of a Hamiltonian that varies in time due to a time-dependent classical field.
Estimation of the heat capacity of CdTe semiconductor
Authors: Koç Hüseyin , Eser Erhan
Published: February 2016

The aim of this paper is to provide a simple and reliable analytical expression for the thermodynamic properties calculated in terms of the Debye model using the binomial coefficient, and examine specific heat capacity of CdTe in the 300–1400 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. The calculated results are in good agreement with the other results over the entire temperature range.
Evolution of extortion in the social-influenced prisoner’s dilemma
Authors: Wang Zhipeng , Li Miao , Wang Dan , Chen Qinghe
Published: February 2016

The introduction of extortion strategy has attracted much attention since it dominates any evolutionary opponent in iterated prisoner’s dilemma games. Despite several studies argue that extortion is difficult to survive under strategy imitation and birth–death updating rules in well-mixed populations, it has recently been proven that a myopic best response rule facilitate the evolution of cooperation and extortion. However, such updating rules require a strong assumption of complete knowledge of all players, which is unlikely to hold in social networks in reality. To solve this problem, we introduce the concept of social influence into the model to limit players’ knowledge within their neighborhood. It turns out that this myopia initiated by social influence prevents players from observing superior strategies and therefore enables cooperators and extortioners to be evolutionarily stable. We also suggest that heterogeneous networks contribute to the evolution of cooperation and extortion under such social influence.
Phonon interaction of electrons in the translation-invariant strong-coupling theory
Authors: Lakhno V. D.
Published: February 2016

A dependence of phonon interaction on the interelectronic distance is found for a translation-invariant (TI) strong-coupling bipolaron. It is shown that the charge induced by the electrons in a TI-bipolaron state is always greater than that in a bipolaron with spontaneously broken symmetry.
Dispersionless optical activity based on novel windmill-shaped chiral metamaterial
Authors: Ma Xiaolong , Xiao Zhongyin , Liu Dejun , Wang Lei , Xu Kai , Tang Jingyao , Wang Zihua
Published: February 2016

In this paper, the optical properties of the novel windmill-shaped chiral metamaterial (CMM) with low ellipticity have been studied numerically in THz band. The dispersionless optical activity can be achieved in a wide frequency range (i.e. from 1.7 THz to 2.7 THz). The dependence of CMM’s optical properties on the structural parameters is studied systematically and the frequency range of low ellipticity can be controlled dynamically through adjusting the width of the metal. The excitation mechanism of optical activity based on the current distribution is also analyzed in detail.
On a moving four-level N-type atom interacting with two-mode cavity field in the presence of the cross-Kerr medium
Authors: Abdel-Wahab N. H. , Thabet Lamia E.
Published: February 2016

In this paper, some properties through the moving four-level [Formula: see text]-type atom interacting with a two-mode radiation field are presented. We study this system in the presence of the nonlinearity. The exact solution of this model is given by using the Schrödinger equation when the atom and the field are initially in an excited state and a squeezed state, respectively. We employed the results to perform a careful investigation of the temporal evolution of the cross-correlation function, the momentum increment, the difference mean photon numbers and the normal squeezing. The influence of the Kerr and the cross-Kerr medium parameters on these aspects is examined. It is found that the atom-field properties are affected by the changing of these parameters.
Photoionization microscopy of hydrogen in magnetic and quadrupolar electric fields
Authors: Yang Hai-Feng , Tan Yong-Gang , Liu Zhong-Li , Fu Hong-Zhi
Published: February 2016

The photoionization microscopy of hydrogen in magnetic and quadrupolar electric fields is studied on the basis of the semiclassical theory. Potential for the studied system possesses saddle points lying in the [Formula: see text]-direction, rather than the [Formula: see text]-direction in the common case, such as atom in the electric field. We find the electron current recorded by cylindrical surface detector shows symmetric interference patterns along [Formula: see text]-direction, and predict that the interference pattern presents the list structure, instead of the cyclic structure observed in the electric field. Besides, the interference structures are assigned to different types of trajectories. As the scaled energy increases, the structure of the interference pattern evolves smoothly and more types of trajectories emerge.
Synthesis of CuO nanowires on Cu-foil using thermal oxidation method, a novel annealing process
Authors: Eshghi Hosein , Goodarzi Mehdi Torabi
Published: February 2016

Cupric oxide (CuO) nanowires (NWs) on Cu-foils were prepared by thermal oxidation method in air atmosphere using two annealing manners (continuous and steps) in the temperature ranges of 400–500[Formula: see text]C and 400–600[Formula: see text]C. Morphology and microstructure of the NWs was studied using field effect scanning electron microscopy (FESEM), X-ray diffractogram (XRD), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Optical reflectance spectrum was used for the optical investigation of the layers. We found the NWs formed have two different morphologies, curved and straight, with diameters between 50 nm and 200 nm and lengths between 5 [Formula: see text]m and 10 [Formula: see text]m. SAED pattern of a single NW revealed as a CuO single crystal with monoclinic structure. The reflectance spectra analysis based on Kubelka–Munk method showed that the band gap energy of the CuO NWs are varying in the range of 1.40–1.47 eV depending on the crystallite sizes of the NWs, a confirmation for the happening of the quantum confined effect in these samples.
One-pot microwave assisted approach for synthesis of CdSe/CdS core-shell quantum dots (QDs) and investigating optical properties
Authors: Molaei M. , Bardsiri F. Salari , Bahador A. R. , Karimipour M.
Published: February 2016

In this work, CdSe QDs were synthesized using a microwave assisted method and chemical reaction between NaHSe, CdSO4 at the presence of TGA as capping molecule. Thereafter without CdSe extraction, CdS shell was grown subsequently around CdSe cores by a reaction based on the heat sensitivity of Na2S2O3 dissociation. Synthesized QDs were characterized by means of X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), UV–Vis and photoluminescence (PL) spectroscopy. All of these analyzes confirmed formation of CdSe QDs and successfully growth of CdS shell on surface of CdSe to forming CdSe/CdS core-shell structure.
An Upper Bound on the k-Modem Illumination Problem
Authors: Duque Frank , Hidalgo-Toscano Carlos
Published: February 2016

A variation on the classical polygon illumination problem was introduced in [Aichholzer et al. EuroCG’09]. In this variant light sources are replaced by wireless devices called [Formula: see text]-modems, which can penetrate a fixed number [Formula: see text], of “walls”. A point in the interior of a polygon is “illuminated” by a [Formula: see text]-modem if the line segment joining them intersects at most [Formula: see text] edges of the polygon. It is easy to construct polygons of [Formula: see text] vertices where the number of [Formula: see text]-modems required to illuminate all interior points is [Formula: see text]. However, no non-trivial upper bound is known. In this paper we prove that the number of kmodems required to illuminate any polygon of [Formula: see text] vertices is [Formula: see text]. For the cases of illuminating an orthogonal polygon or a set of disjoint orthogonal segments, we give a tighter bound of [Formula: see text]. Moreover, we present an [Formula: see text] time algorithm to achieve this bound.
Schreir graphs: Transitivity and coverings
Authors: Leemann Paul-Henry
Published: February 2016

We give a characterization of isomorphisms between Schreier graphs in terms of the groups, subgroups and generating systems. This characterization may be thought as a graph analog of Mostow’s rigidity theorem for hyperbolic manifolds. This allows us to give a transitivity criterion for Schreier graphs. Finally, we show that Tarski monsters satisfy a strong simplicity criterion. This gives a partial answer to a question of Benjamini and Duminil-Copin.
f(ϕ)R-models for inflation
Authors: Myrzakul Shynaray , Myrzakulov Ratbay , Sebastiani Lorenzo
Published: February 2016

In this paper, we investigate models where a scalar field driving inflation is nonminimally coupled with gravity and it is subjected to a scalar potential. We present several examples of coupling between the field and gravity, and we furnish realistic models for inflation in agreement with the last Planck results.
Novel collective phenomena in high-energy proton–proton and proton–nucleus collisions
Authors: Dusling Kevin , Li Wei , Schenke Björn
Published: February 2016

The observation of long-range rapidity correlations among particles in high-multiplicity p–p and p–Pb collisions has created new opportunities for investigating novel high-density QCD phenomena in small colliding systems. We review experimental results related to the study of collective phenomena in small systems at RHIC and the LHC along with the related developments in theory and phenomenology. Perspectives on possible future directions for research are discussed with the aim of exploring emergent QCD phenomena.
Relative entropy of entanglement of two-qubit Ux-invariant states
Authors: Wang Zhen , Wang Zhi-Xi
Published: February 2016

It is strictly proved that a two-qubit [Formula: see text]-invariant state reaches its relative entropy of entanglement (REE) by the separable state having the same matrix structure. We also formulate three quadratic equations for the corresponding closest separable state (CSS) of [Formula: see text]-invariant states by their symmetric property. Thus, the CSS of [Formula: see text]-invariant state can be provided. Furthermore, to illustrate our result we consider two concrete examples.
Security of direct communication quantum channel with feedback
Authors: Usenko Constantin V.
Published: February 2016

In the direct communication quantum channels, the authorized recipient (Bob) and the non-authorized recipient (Eve) have different abilities for verification of received information. Bob can apply the feedback to commit the sender (Alice) to perform verification. Eve has to use for verification an indirect method based on the measurement of a set of incompatible observables enough for determination of the coding basis used by Alice.

In the protocol of direct communication, regular modification of coding basis and masking it with an equilibrium in average information carrier density matrix prevents reconstruction of coding basis by the results of Eve’s measurements of an arbitrary set of observables. This provides unconditional security of the channel.
An Effective Improved Algorithm for Finite Particle Method
Authors: Yang Yang , Xu Fei , Zhang Meng , Wang Lu
Published: February 2016

The low accuracy near the boundary or the interface in SPH method has been paid extensive attention. The Finite Particle Method (FPM) is a significant improvement to the traditional SPH method, which can greatly improve the computational accuracy for boundary particles. However, there are still some inherent defects for FPM, such as the long computing time and the potential numerical instability. By conducting matrix decomposition on the basic equations of FPM, an improved FPM method (IFPM) is proposed, which can not only maintain the high accuracy of FPM for boundary particles, but also keep the invertibility of the coefficient matrix in FPM. The numerical results show that the IFPM is really an effective improvement to traditional FPM, which could greatly reduce the computing time. Finally, the modified method is applied to two transient problems.
A Complete Algorithm for the Reduction of Pattern Data in the Classification of Interval Information
Authors: Kowalski Piotr A. , Kulczycki Piotr
Published: February 2016

The aim of this paper is to present a novel method of data sample reduction that can be applied, in particular, to the classification of interval type imprecise information. Its concept is based on the sensitivity method, inspired by artificial neural networks, while the goal is to increase the number of apposite classifications, and, consequently, to increase calculation speed. As evident in this paper, the use of reduction algorithm eliminates the particular elements of all data sample patterns which have insignificant or negative influence on the correctness of classification. The methodology was tested on pseudo-random and real data, as well as by way of comparative analysis with similar task algorithms. The presented procedure was also tested for use in situations in which the data sample representing the individual classes had been obtained by the k-means clustering procedure.
A START-UP GENERATION APPROACH FOR TEACHING ENTREPRENEURSHIP: AN OVERVIEW OF AFFECTIVE LEARNING RESULTS
Authors: LOI MICHELA , DI GUARDO MARIA CHIARA
Published: February 2016

This study reports an analysis of the training objectives achieved by students with a heterogeneous educational background who attended a university entrepreneurial course. The course emphasized an experiential approach of a start-up creation. A pre-experimental design was followed to collect data on a sample of fourteen students who completed the six-month course. Findings, based on a non-parametric test, show significant differences between the pre and post-test. After the course, participants displayed a higher level of self-efficacy in making decisions, a higher level of probability of becoming entrepreneurs and a lower level of pessimism in projecting their future. Despite deserving to be corroborated with a more sophisticated research design, this study contributes to the extant literature by providing further empirical support about the role played by entrepreneurial courses in fostering harbinger variables of entrepreneurial behavior. Future research issues and practical implications are illustrated with respect to optimism and pessimism.
THE ROLE OF INFORMAL AND FORMAL NETWORKS: HOW PROFESSIONALS CAN BE INNOVATIVE IN A CONSTRAINED FISCAL ENVIRONMENT
Authors: BRUNETTO YVONNE , XERRI MATTHEW J. , NELSON SILVIA , FARR-WHARTON BENJAMIN
Published: February 2016

One way of circumventing issues associated with constricted resources is to use organisational social resources embedded within both formal and informal social networks to provide increased support for proactive and innovative employee behaviour. Social exchange theorists argue that informal working relationships with non-line management provides an additional power source alongside traditional management relationships to foster proactive and innovative behaviour even when resources are scarce. About 272 Australian engineers, asset managers and technical employees were surveyed from public and private sector organisations, and data was examined using structural equation modelling. The findings depict that formal and informal leader–employee, organisational–employee relationships explained almost 53% of resource adequacy and resource adequacy explained 60.5% of the proactive engineering asset management organisational culture and 28.1% of innovative behaviour. This paper contributes insight into another hierarchical workplace relationship that employees can use to gain access to resources, and be proactive and innovative in the workplace.
Relevance Meets Coverage
Authors: Wu Le , Liu Qi , Chen Enhong , Yuan Nicholas Jing , Guo Guangming , Xie Xing
Published: February 2016

Collaborative filtering (CF) models offer users personalized recommendations by measuring the
relevance
between the active user and each individual candidate item. Following this idea, user-based collaborative filtering (UCF) usually selects the local popular items from the like-minded neighbor users. However, these traditional relevance-based models only consider the individuals (i.e., each neighbor user and candidate item) separately during neighbor set selection and recommendation set generation, thus usually incurring highly similar recommendations that lack diversity. While many researchers have recognized the importance of diversified recommendations, the proposed solutions either needed additional semantic information of items or decreased accuracy in this process. In this article, we describe how to generate both accurate and diversified recommendations from a new perspective. Along this line, we first introduce a simple measure of
coverage
that quantifies the usefulness of the whole set, that is, the neighbor userset and the recommended itemset as a complete entity. Then we propose a recommendation framework named REC that considers both traditional relevance-based scores and the new coverage measure based on UCF. Under REC, we further prove that the goals of maximizing relevance and coverage measures simultaneously in both the neighbor set selection step and the recommendation set generation step are NP-hard. Luckily, we can solve them effectively and efficiently by exploiting the inherent submodular property. Furthermore, we generalize the coverage notion and the REC framework from both a data perspective and an algorithm perspective. Finally, extensive experimental results on three real-world datasets show that the REC-based recommendation models can naturally generate more diversified recommendations without decreasing accuracy compared to some state-of-the-art models.
Translating Principles of Effective Feedback for Students into the CS1 Context
Authors: Ott Claudia , Robins Anthony , Shephard Kerry
Published: February 2016

Learning the first programming language is challenging for many students. High failure rates and bimodally distributed grades lead to a pedagogical interest in supporting students in first-year programming courses (CS1). In higher education, the important role of feedback for guiding the learning process and improving the learning outcome is widely acknowledged. This article introduces contemporary models of effective feedback practice as found in the higher education literature and offers an interpretation of those in the CS1 context. One particular CS1 course and typical course components are investigated to identify likely loci for feedback interventions and to connect related computer science education literature to these forms of feedback.
Remark on “Algorithm 673
Authors: Novoselsky Alexander , Kagan Eugene
Published: February 2016

This remark presents a correction to Algorithm 673 (dynamic Huffman coding) [Vitter 1989] and its translation to MATLAB.
An Efficient Algorithm For Weak Hierarchical Lasso
Authors: Liu Yashu , Wang Jie , Ye Jieping
Published: February 2016

Linear regression is a widely used tool in data mining and machine learning. In many applications, fitting a regression model with only linear effects may not be sufficient for predictive or explanatory purposes. One strategy that has recently received increasing attention in statistics is to include feature interactions to capture the nonlinearity in the regression model. Such model has been applied successfully in many biomedical applications. One major challenge in the use of such model is that the data dimensionality is significantly higher than the original data, resulting in the small sample size large dimension problem. Recently, weak hierarchical Lasso, a sparse interaction regression model, is proposed that produces a sparse and hierarchical structured estimator by exploiting the Lasso penalty and a set of hierarchical constraints. However, the hierarchical constraints make it a non-convex problem and the existing method finds the solution to its convex relaxation, which needs additional conditions to guarantee the hierarchical structure. In this article, we propose to directly solve the non-convex weak hierarchical Lasso by making use of the General Iterative Shrinkage and Thresholding (GIST) optimization framework, which has been shown to be efficient for solving non-convex sparse formulations. The key step in GIST is to compute a sequence of proximal operators. One of our key technical contributions is to show that the proximal operator associated with the non-convex weak hierarchical Lasso admits a closed-form solution. However, a naive approach for solving each subproblem of the proximal operator leads to a quadratic time complexity, which is not desirable for large-size problems. We have conducted extensive experiments on both synthetic and real datasets. Results show that our proposed algorithm is much more efficient and effective than its convex relaxation. To this end, we further develop an efficient algorithm for computing the subproblems with a linearithmic time complexity. In addition, we extend the technique to perform the optimization-based hierarchical testing of pairwise interactions for binary classification problems, which is essentially the proximal operator associated with weak hierarchical Lasso. Simulation studies show that the non-convex hierarchical testing framework outperforms the convex relaxation when a hierarchical structure exists between main effects and interactions.
Mining User Development Signals for Online Community Churner Detection
Authors: Rowe Matthew
Published: February 2016

Churners are users who stop using a given service after previously signing up. In the domain of telecommunications and video games, churners represent a loss of revenue as a user leaving indicates that they will no longer pay for the service. In the context of online community platforms (e.g., community message boards, social networking sites, question--answering systems, etc.), the churning of a user can represent different kinds of loss: of social capital, of expertise, or of a vibrant individual who is a mediator for interaction and communication. Detecting which users are likely to churn from online communities, therefore, enables community managers to offer incentives to entice those users back; as retention is less expensive than re-signing users up. In this article, we tackle the task of detecting churners on four online community platforms by mining user development signals. These signals explain how users have evolved along different dimensions (i.e., social and lexical) relative to their prior behaviour and the community in which they have interacted. We present a linear model, based upon elastic-net regularisation, that uses extracted features from the signals to detect churners. Our evaluation of this model against several state of the art baselines, including our own prior work, empirically demonstrates the superior performance that this approach achieves for several experimental settings. This article presents a novel approach to churn prediction that takes a different route from existing approaches that are based on measuring static social network properties of users (e.g., centrality, in-degree, etc.).
Power-Aware Design Techniques of Secure Multimode Embedded Systems
Authors: Jiang Ke , Eles Petru , Peng Zebo
Published: February 2016

Nowadays, embedded systems have been widely used in all types of application areas, some of which belong to the safety and reliability critical domains. The functional correctness and design robustness of the embedded systems involved in such domains are crucial for the safety of personal/enterprise property or even human lives. Thereby, a holistic design procedure that considers all the important design concerns is essential.

In this article, we approach embedded systems design from an integral perspective. We consider not only the classic real-time and quality of service requirements, but also the emerging security and power efficiency demands. Modern embedded systems are not any more developed for a fixed purpose, but instead designed for undertaking various processing requests. This leads to the concept of multimode embedded systems, in which the number and nature of active tasks change during runtime. Under dynamic situations, providing high performance along with various design concerns becomes a really difficult problem. Therefore, we propose a novel power-aware secure embedded systems design framework that efficiently solves the problem of runtime quality optimization with security and power constraints. The efficiency of our proposed techniques are evaluated in extensive experiments.
Parallel Power Grid Analysis Based on Enlarged Partitions
Authors: Zhang Le , Sarin Vivek
Published: February 2016

As the size and complexity of current VLSI circuits grows, faster power grid simulation is becoming more and more desirable. In this article, we present a parallel iterative method for static VLSI power grid simulation. In the proposed enlarged-partition-based preconditioned conjugate gradient (EPPCG) power grid solver, the power grid is divided into disjoint partitions that are subsequently enlarged to obtain accurate solution within each partition. The global solution obtained by solving enlarged partition problems concurrently acts as a highly effective parallel preconditioner. The combination of effective preconditioning and efficient parallelization helps achieve very high performance. The experiments show that our parallel implementation can achieve significant speed improvement [61X--142X] over a state-of-the-art direct solver.
Using Bisect K-Means Clustering Technique in the Analysis of Arabic Documents
Authors: Abuaiadah Diab
Published: February 2016

In this article, I have investigated the performance of the bisect K-means clustering algorithm compared to the standard K-means algorithm in the analysis of Arabic documents. The experiments included five commonly used similarity and distance functions (Pearson correlation coefficient, cosine, Jaccard coefficient, Euclidean distance, and averaged Kullback-Leibler divergence) and three leading stemmers. Using the purity measure, the bisect K-means clearly outperformed the standard K-means in all settings with varying margins. For the bisect K-means, the best purity reached 0.927 when using the Pearson correlation coefficient function, while for the standard K-means, the best purity reached 0.884 when using the Jaccard coefficient function. Removing stop words significantly improved the results of the bisect K-means but produced minor improvements in the results of the standard K-means. Stemming provided additional minor improvement in all settings except the combination of the averaged Kullback-Leibler divergence function and the root-based stemmer, where the purity was deteriorated by more than 10%. These experiments were conducted using a dataset with nine categories, each of which contains 300 documents.
A Cost-Effective Energy Optimization Framework of Multicore SoCs Based on Dynamically Reconfigurable Voltage-Frequency Islands
Authors: Jin Song , Pei Songwei , Han Yinhe , Li Huawei
Published: February 2016

Voltage-frequency island (VFI)-based design has been widely exploited for optimizing system energy of embedded multicore chip in recent years. The existing work either constructed a single static VFI partition for all kinds of applications or required per-core voltage domain configuration. However, the former solution is hard to find one optimal VFI partition for diverse applications while the latter one suffers from high hardware cost. In this article, we propose a cost effective energy optimization framework based on dynamically reconfigurable VFI (D-VFI). Our framework treats a small number of cores as dynamic cores (D-cores) and configures each of them with an independent voltage domain. At runtime, the D-cores can be pieced together with neighboring static VFIs by scaling their operating voltages. This can dynamically construct the optimal VFI partitions for different kinds of applications, thus achieving more aggressive energy optimization under low cost. To identify the D-cores, we propose a rules constrained task scheduling and VFI partitioning algorithm. Moreover, we analyze the task schedules to determine the optimal scaling intervals which can accommodate voltage scaling induced latency. Experimental results demonstrate that the effectiveness of the proposed scheme.
Collective Graph Identification
Authors: Namata Galileo Mark , London Ben , Getoor Lise
Published: February 2016

Data describing networks—such as communication networks, transaction networks, disease transmission networks, collaboration networks, etc.—are becoming increasingly available. While observational data can be useful, it often only hints at the actual underlying process that governs interactions and attributes. For example, an email communication network provides insight into its users and their relationships, but is not the same as the “real” underlying social network. In this article, we introduce the problem of
graph identification
, i.e., discovering the latent graph structure underlying an observed network. We cast the problem as a probabilistic inference task, in which we must infer the nodes, edges, and node labels of a hidden graph, based on evidence. This entails solving several canonical problems in network analysis:
entity resolution
(determining when two observations correspond to the same entity),
link prediction
(inferring the existence of links), and
node labeling
(inferring hidden attributes). While each of these subproblems has been well studied in isolation, here we consider them as a single, collective task. We present a simple, yet novel, approach to address all three subproblems simultaneously. Our approach, which we refer to as
C
3
, consists of a collection of Coupled Collective Classifiers that are applied iteratively to propagate inferred information among the subproblems. We consider variants of
C
3
using different learning and inference techniques and empirically demonstrate that
C
3
is superior, both in terms of predictive accuracy and running time, to state-of-the-art probabilistic approaches on four real problems.
Performance-Driven Assignment of Buffered I/O Signals in Area-I/O Flip-Chip Designs
Authors: Yan Jin-Tai
Published: February 2016

Due to the inappropriate assignment of bump pads or the improper assignment of I/O buffers, the constructed buffered I/O signals in an area-I/O flip-chip design may yield longer maximum delay. In this article, the problem of assigning performance-driven buffered I/O signals in an area-I/O flip-chip design is first formulated. Furthermore, the assignment of the buffered I/O signals can be divided into two sequential phases: Construction of performance-driven I/O signals and Assignment of timing-constrained I/O buffers. Finally, an efficient matching-based approach is proposed to construct the performance-driven I/O signals for the given I/O pins and assign the timing-constrained I/O buffers into the constructed I/O signals in the assignment of the buffered I/O signals in an area-I/O flip-chip design. Compared with the experimental results of seven tested circuits in the Elmore delay model, the experimental results show that the matching-based assignment in our proposed approach can reduce 3.56% of the total path delay, 9.72% of the maximum input delay, 5.90% of the input skew, 5.64% of the maximum output delay, and 6.25% of the output skew on average by reassigning the I/O buffers. Our proposed approach can further reduce 38.89% of the total path delay, 44.00% of the maximum input delay, 49.13% of the input skew, 44.93% of the maximum output delay, and 50.82% of output skew on average by reconstructing the I/O signals and reassigning the I/O buffers into the I/O signals. Compared with the experimental results of seven tested circuits in Peng's [Peng et al. 2006] publication, the experimental results show that our proposed matching-based approach can further reduce 71.06% of the total path delay, 67.83% of the maximum input delay, 59.84% of the input skew, 68.87% of the maximum output delay, and 61.46% of the output skew on average. On the other hand, compared with the experimental results of five tested circuits in Lai's [Lai and Chen 2008] publication, the experimental results show that our proposed approach can further reduce 75.36% of the total path delay, 48.94% of the input skew, and 52.80% of the output skew on the average.