bluuebunny/crossref_metadata_2025 huggingface dataset:
AN INTERVAL ANALYSIS METHOD FOR WRENCH WORKSPACE DETERMINATION OF PARALLEL MANIPULATOR ARCHITECTURES
Authors: Pickard Joshua K. , Carretero Juan A.
Published: April 2018

This paper deals with the wrench workspace (WW) determination of parallel manipulators. The WW is the set of end-effector poses (positions and orientations) for which the active joints are able to balance a set of external wrenches acting at the end-effector. The determination of the WW is important when selecting an appropriate manipulator design since the size and shape of the WW are dependent on the manipulator’s geometry (design) and selected actuators. Algorithms for the determination of the reachable workspace and the WW are presented. The algorithms are applicable to manipulator architectures utilizing actuators with positive and negative limits on the force/torque they can generate, as well as cable-driven parallel manipulator architectures which require nonnegative actuator limits to maintain positive cable tensions. The developed algorithms are demonstrated in case studies applied to a cable-driven parallel manipulator with 2-degrees-of-freedom and three cables and to a 3-RRR parallel manipulator. The approaches used in this paper provide guaranteed results and are based on methods utilizing interval analysis techniques for the representation of end-effector poses and design parameters.
TRAJECTORY OPTIMIZATION OF A SMALL AIRSHIP IN A MOVING FLUID
Authors: Blouin Charles , Lanteigne Eric , Gueaieb Wail
Published: April 2018

Airships offer a low-cost alternative to heavier-than-air vehicles for long endurance applications in surveillance and transport. Although manoeuvring an under-actuated vehicle in a real environment while taking into account the obstacles, the dynamical model, the wind, and the energy consumption has been studied extensively, planning complex manoeuvres in constrained environments remains an active research area. This paper examines the use of optimal control for the trajectory planning of a small airship. The dynamic model of the vehicle and the experimental characterization of the drag coefficient are presented first, followed by the description of the trajectory planning problem formulated as an optimal control problem. Two trajectories are then solved using a pseudo-spectral solver to demonstrate that an optimal control approach can be used to generate complex and realistic manoeuvres.
IMPROVING ELECTRO-HYDRAULIC SYSTEM PERFORMANCE BY DOUBLE-VALVE ACTUATION
Authors: Bai Yanhong , Quan Long
Published: April 2018

Restricted by narrow bandwidth of the existing high-flow servo valves, dynamic performance of high-flow electro-hydraulic servo systems can only be enhanced to a certain extent by advanced control algorithms. This paper proposes a new hydraulic control circuit, in which two valves are arranged in parallel to control the actuator jointly. Frequency response of the equivalent valve is raised and thereby the performance of high-flow electro-hydraulic servo systems can be improved. A model of the proposed system is built and the principle of improving system dynamic performance using the new circuit is analyzed. Simulation results show that double-valve actuation schemes can quicken system response and increase system bandwidth regardless to if the two valves have the same or different behaviors.
INVESTIGATION OF INLET EFFECTS ON BACKWARD-FACING STEP FLOW PREDICTION
Authors: Isman Mustafa Kemal
Published: April 2018

The turbulent flow over backward-facing step (BFS) is numerically investigated by using FLUENT® code. Both uniform and non-uniform velocity profiles are used as inlet boundary condition. Five different Reynolds averaged Navier–Stokes (RANS) turbulence models are employed. The Std. k–ω model shows the best agreement with the experimental data among the models used under the conditions considered in this study. The results show that using a uniform velocity profile has a negative effect on predictions if the domain is not sufficiently extended upstream from the inlet. To eliminate this effect, the domain should be extended upstream by about 10Dh from the inlet. However, results show that this extension causes absorption effects of inlet parameters such as inlet turbulence intensity.
RESEARCH ON THE FREQUENCY RELIABILITY SENSITIVITY AND RELIABILITY-BASED ROBUST DESIGN OF THE RANDOM VIBRATION SYSTEM OF CONTINUOUS ROD
Authors: Lü Chunmei , Zhang Yimin , Li He , Zhou Na
Published: April 2018

The frequency reliability sensitivity in the stochastic dynamic structure system and reliability-based robust design were studied deeply in this paper. With the criterion that the absolute value of the difference between natural frequency and forcing frequency, the frequency reliability method of avoiding resonance was proposed. Then frequency reliability sensitivity theory was presented, which provided a preliminary efficient way to analyze how each random parameter contributed to the system reliability. Moreover, the frequency reliability-based robust design method was obtained by robust and optimization technology on the basis of the frequency reliability and sensitivity research in the paper, which helped designers to establish acceptable parameter values and to determine the fluctuations of the parameters for the safe operations. Meanwhile, a numerical example of the random vibration system of continuous rod was provided and studied. The effectiveness and accuracy of the proposed methods were well demonstrated.
FULL SCALE EXPERIMENT AND NUMERICAL ANALYSIS FOR THE PERFORMANCE OF HEAT EXCHANGER IN MOLTEN CARBONATE FUEL CELLS
Authors: Kim Seon-Hwa , Choi Byeong-Keun , An Young-Su
Published: April 2018

This study presents a numerical simulation of heat transfer and flow characteristics of the heat exchanger in molten carbonate fuel cell system. In this study, the actual size of the heat exchanger was simulated in order to avoid errors that can occur from the scale-down test, also the simulation gas (air) was verified with the heat duty of 800,000 kcal/hr. It is analyzed by using a commercial heat exchanger calculation code based upon the test condition. It is found that a reasonable agreement is obtained from comparison between the predicted results and the measured data. Furthermore, the verified similarity was presented in this analysis. In particular, the simulation gas used for the shell side service for the heat exchanger is obtained through the combustion calculation, i.e. by using a flow rate of the fuel gas. In addition, the performance of the heat exchanger is predicted under various conditions in the fuel cell operation conditions by the numerical model.
OPTIMAL PREDICTION AND DESIGN OF SURFACE ROUGHNESS FOR CNC TURNING OF AL7075-T6 BY USING THE TAGUCHI HYBRID QPSO ALGORITHM
Authors: Chen Wen-Jong , Huang Chuan-Kuei , Yang Qi-Zheng , Yang Yin-Liang
Published: April 2018

This paper combines the Taguchi-based response surface methodology (RSM) with a multi-objective hybrid quantum-behaved particle swarm optimization (MOHQPSO) to predict the optimal surface roughness of Al7075-T6 workpiece through a CNC turning machining. First, the Taguchi orthogonal array L27 (36) was applied to determine the crucial cutting parameters: feed rate, tool relief angle, and cutting depth. Subsequently, the RSM was used to construct the predictive models of surface roughness (Ra, Rmax, and Rz). Finally, the MOHQPSO with mutation was used to determine the optimal roughness and cutting conditions. The results show that, compared with the non-optimization, Taguchi and classical multi-objective particle swarm optimization methods (MOPSO), the roughness Ra using MOHQPSO along the Pareto optimal solution are improved by 68.24, 59.31 and 33.80%, respectively. This reveals that the predictive models established can improve the machining quality in CNC turning of Al7075-T6.
DYNAMIC MODELING AND ANALYSIS OF MULTI-STAGE PLANETARY GEARS COUPLED WITH CENTRAL BEARINGS AND HOUSING
Authors: Xiao Zheng-Ming , Wu Xing , Chen Qing
Published: April 2018

This paper proposes a coupling dynamic model for multi-stage planetary gears train (PGT) based on the gearing theory and Lagrange equation, which is developed by analyzing the displacement relationships of gearing system and the influence of floating components. The time-varying mesh stiffness, bearings in housing, and the torsional support stiffness of ring gears are also considered. This model has 26 degrees-of-freedom (DOF) and adopts three planar DOFs for each central component, mesh phasing relations among planetary gears, and the rotational DOF for the planets of each stage. The modified transverse-torsional model is established in the rotating Cartesian coordinates by using the lumped-parameter method; thus this model is more accurate than the purely torsional model for describing the physical dynamics. The acceleration data is tested by using the scheme of a back-to-back power circulation set-up, and the vibration properties are also studied.
Design and development of tractor clutch using combined field and bench tests
Authors: Karpat Fatih , Yuce Celalettin , Dogan Oguz , Genç Mehmet Onur , Kaya Necmettin
Published: April 2018

Tractors, the primary component of agricultural mechanization, are actively used for maintaining agricultural activities and carrying burdens on agricultural fields under challenging conditions. Tractors are not only required to possess a high tractive force at low operating speeds but also to produce the power necessary for operating the equipment attached to them when used for agricultural purposes. It is of great importance to determine the degree of force that powertrains, especially the clutch, of the tractors are exposed to on agricultural fields and to use the data obtained in this process concerning their guarantee periods. This study measured the motor rotation speed, clutch surface temperature, and frequency and force of pushing the clutch pedal of a tractor used under five different agricultural field conditions. Furthermore, torque and transfer of the dynamometer and power take-off (PTO) were measured. Based on the data obtained from field tests, the tractor clutch development and validation processes were revised. The prototype clutch was produced and tested by completing the required 1 million rotations safely under new boundary conditions within the guarantee period.
Influence of temperature diffusion on molecular reorientation in nematic liquid crystals
Authors: Sala Filip A. , Sala-Tefelska Marzena M. , Bujok Maksymilian J.
Published: April 2018

In this paper, the theoretical analyses of optically induced molecular reorientation are presented in a nematic liquid crystal cell. Due to the absorption of the light beam, the temperature of the cell increases, which induces change of anisotropy and the Frank elastic coefficients. In our analyses, a simple model is used. It is based on the Frank–Oseen elastic theory to describe molecular reorientation and on a heat diffusion equation to model thermal effects. Molecular reorientation, its width and maximum value, and extraordinary refractive index are analyzed versus various values of absorption coefficient, rate of change of elastic coefficient, and thermal conductance. It appears that thermal effects do not influence the width of the molecular reorientation. The nonlocality is nearly unaffected by the increase of temperature. However, the maximum molecular reorientation might increase with temperature, in most cases, the extraordinary refractive index decreases with temperature. Only for unlikely high rates of change of elastic coefficients, the refractive index increases with temperature. Moreover, the transition between liquid crystal and isotropic phases is also discussed. The range of input beam width for which the material lasts in a liquid crystal state is also presented. Simulations are performed for parameters corresponding to two liquid crystals: low birefringent 1550 and 6CHBT of a medium birefringence.
Waiting Time for Transient Violations of the Second Law in Brownian Oscillators
Authors: Sarasua L. G. , Cabrera C.
Published: April 2018

In this work, we study the average time a Brownian oscillator coupled to a thermal bath takes to get fluctuations of a given energy. The waiting times are obtained as a function of the system parameters using the Langevin equation and molecular simulations. We found that an oscillators system can exhibit arbitrarily large transient violations of the second law. It is shown that the waiting times give relevant information that is not provided by the solutions of the Fokker–Planck equation.
Recurrence and transience for normally reflected Brownian motion in warped product manifolds
Authors: de Lima Levi Lopes
Published: April 2018

We establish an integral test describing the exact cut-off between recurrence and transience for normally reflected Brownian motion in certain unbounded domains in a class of warped product manifolds. Besides extending a previous result by Pinsky, who treated the case in which the ambient space is flat, our result recovers the classical test for the standard Brownian motion in model spaces. Moreover, it allows us to discuss the recurrence/transience dichotomy for certain generalized tube domains around totally geodesic submanifolds in hyperbolic space.
Finite σ-soluble groups in which σ-permutability is a transitive relation
Authors: Zhu Xiaoxing , Cao Chenchen , Guo Wenbin
Published: April 2018

Let [Formula: see text] be some partition of the set of all primes [Formula: see text], [Formula: see text] a finite group and [Formula: see text]. A set [Formula: see text] of subgroups of [Formula: see text] is said to be a complete Hall[Formula: see text]-set of [Formula: see text] if every member [Formula: see text] of [Formula: see text] is a Hall [Formula: see text]-subgroup of [Formula: see text] for some [Formula: see text] and [Formula: see text] contains exactly one Hall [Formula: see text]-subgroup of [Formula: see text] for every [Formula: see text]. A subgroup [Formula: see text] of [Formula: see text] is said to be [Formula: see text]-quasinormal or [Formula: see text]-permutable in [Formula: see text] provided there is a complete Hall [Formula: see text]-set [Formula: see text] of [Formula: see text] such that [Formula: see text] for all [Formula: see text] and all [Formula: see text].

In this paper, we study the structure of some generalized soluble groups [Formula: see text] in which [Formula: see text]-permutability is a transitive relation in [Formula: see text].
Enumerating Cayley (di-)graphs on dihedral groups
Authors: Huang Xueyi , Huang Qiongxiang
Published: April 2018

Let [Formula: see text] be an odd prime, and [Formula: see text] the dihedral group of order [Formula: see text]. In this paper, we provide the number of (connected) Cayley (di-)graphs on [Formula: see text] up to isomorphism by using the Pólya enumeration theorem. In the process, we also enumerate (connected) Cayley digraphs on [Formula: see text] of out-degree [Formula: see text] up to isomorphism for each [Formula: see text].
An algorithm for regular solutions of systems of exp-subanalytic equations and o-minimality of ℝan,exp
Authors: Pawłucki Wiesław , Rożen Zofia
Published: April 2018

We describe an algorithm which reduces (the problem of finding regular solutions of) a system of [Formula: see text]-subanalytic equations to (the same problem for) a finite number of systems of subanalytic equations, by using the following operations: restriction to an open [Formula: see text]-subanalytic subset, smooth [Formula: see text]-subanalytic change of variables and restriction to a linear subspace. An application of this together with a theorem of Lion is that the structure [Formula: see text] is o-minimal.
Heisenberg uncertainty inequality for certain Lie groups
Authors: Smaoui Kais
Published: April 2018

We establish analogues of Heisenberg uncertainty inequality for some classes of Lie groups, such as connected and simply connected nilpotent Lie groups, diamond Lie groups and Heisenberg motion groups.
Numerical treatment of fractional-order nonlinear system of delay integro-differential equations arising in biology
Authors: Mohammadi F. , Moradi L.
Published: April 2018

This paper presents a fractional-order nonlinear system of delay integro-differential equations which is used to model biological species living together. A numerical scheme based on the Chelyshkov polynomials is implemented to solve this fractional order system of integro-differential equations. The main advantages of the presented method is that it reduces under consideration problem to a system of nonlinear algebraic equations. Some test problems are considered to confirm validity and accuracy of the presented method. Moreover, the obtained numerical results are compared with those existing in the literature.
Modelling the 1929 Grand Banks slump and landslide tsunami
Authors: Løvholt Finn , Schulten Irena , Mosher David , Harbitz Carl , Krastel Sebastian
Published: April 2018

On 18 November 1929, an M
w
7.2 earthquake occurred south of Newfoundland, displacing >100 km
3
of sediment volume that evolved into a turbidity current. The resulting tsunami was recorded across the Atlantic and caused fatalities in Newfoundland. This tsunami is attributed to sediment mass failure because no seafloor displacement due to the earthquake has been observed. No major headscarp, single evacuation area nor large mass transport deposit has been observed and it is still unclear how the tsunami was generated. There have been few previous attempts to model the tsunami and none of these match the observations. Recently acquired seismic reflection data suggest that rotational slumping of a thick sediment mass may have occurred, causing seafloor displacements up to 100 m in height. We used this new information to construct a tsunamigenic slump source and also carried out simulations assuming a translational landslide. The slump source produced sufficiently large waves to explain the high tsunami run-ups observed in Newfoundland and the translational landslide was needed to explain the long waves observed in the far field. However, more analysis is needed to derive a coherent model that more closely combines geological and geophysical observations with landslide and tsunami modelling.
Multiple lines of field evidence to inform fracture network connectivity at a shale site contaminated with dense non-aqueous phase liquids
Authors: Parker Beth L. , Chapman Steven W. , Goldstein Kenneth J. , Cherry John A.
Published: April 2018

Conceptual models of the fracture networks in shale were evaluated at a site contaminated with chlorinated solvents. Prior borehole testing in eight holes under open hole ambient and pumping conditions identified 14 flow zones (140 m bedrock interval) with zero to five zones per hole. Cross-hole testing showed only a few cross-connections between transmissive fractures. The initial conceptual model thus featured a sparse fracture network with few dominant fractures. Detailed profiles (hydraulic head, rock core volatile organic compounds, groundwater volatile organic compounds from packer and multi-level sampling, cross-hole multi-level monitoring of permanganate injections) were collected from several holes and indicated a well-connected fracture network with many hydraulically active fractures not influenced by open hole cross-connection. This contrasting conceptual model contained numerous well-connected horizontal and vertical fractures that allowed chlorinated solvents to penetrate the upper 50–60 m of bedrock as dense non-aqueous phase liquids, followed by diffusion-driven mass transfer from fractures into the porous rock matrix, such that nearly all the contaminant mass resided as dissolved and sorbed phases, measurable in rock core without cross-contamination during drilling. The difference in the two conceptual models has important implications for source zone and plume attenuation.
Geikie's field researches and their geological controversies
Authors: Butler Robert W. H. , Matthews Stephen J. , Morgan Richard K.
Published: April 2018

Archibald Geikie's (1835–1924) field research led to better understanding of geological relationships and, ultimately, Earth processes. We consider three pieces of research in Scotland, from his early work on Skye through to the execution and impact of his 1860 expedition to the NW Highlands with Murchison, returning to Skye to consider arguments with Judd on igneous relationships. We describe the field locations and place modern interpretations in their historical context. We discuss how methods and approaches for building interpretations in the field were modified and improved through debates. Reliance on a few ‘critical outcrops’ served to anchor interpretation at the expense of understanding more complex exposures. Similar bias appears to have arisen from using simple exploratory transects which were only mitigated by proper mapping approaches. Significant misunderstandings between protagonists appear to have arisen through the reliance of text description rather than diagrammatic illustrations. The vitriolic nature of debate seems to have anchored misinterpretations, obscured interpretational uncertainty and promoted false-reasoning by inhibiting inclusive scientific engagement.
Virtual Rephotography
Authors: Waechter Michael , Beljan Mate , Fuhrmann Simon , Moehrle Nils , Kopf Johannes , Goesele Michael
Published: April 2018

The ultimate goal of many image-based modeling systems is to render photo-realistic novel views of a scene without visible artifacts. Existing evaluation metrics and benchmarks focus mainly on the geometric accuracy of the reconstructed model, which is, however, a poor predictor of visual accuracy. Furthermore, using only geometric accuracy by itself does not allow evaluating systems that either lack a geometric scene representation or utilize coarse proxy geometry. Examples include a light field and most image-based rendering systems. We propose a unified evaluation approach based on novel view prediction error that is able to analyze the visual quality of
any
method that can render novel views from input images. One key advantage of this approach is that it does not require ground truth geometry. This dramatically simplifies the creation of test datasets and benchmarks. It also allows us to evaluate the quality of an unknown scene during the acquisition and reconstruction process, which is useful for acquisition planning. We evaluate our approach on a range of methods, including standard geometry-plus-texture pipelines as well as image-based rendering techniques, compare it to existing geometry-based benchmarks, demonstrate its utility for a range of use cases, and present a new virtual rephotography-based benchmark for image-based modeling and rendering systems.
Boundary Element Octahedral Fields in Volumes
Authors: Solomon Justin , Vaxman Amir , Bommes David
Published: April 2018

The computation of smooth fields of orthogonal directions within a volume is a critical step in hexahedral mesh generation, used to guide placement of edges and singularities. While this problem shares high-level structure with surface-based frame field problems, critical aspects are lost when extending to volumes, while new structure from the flat Euclidean metric emerges. Taking these considerations into account, this article presents an algorithm for computing such “octahedral” fields. Unlike existing approaches, our formulation achieves
infinite
resolution in the interior of the volume via the boundary element method (BEM), continuously assigning frames to points in the interior from only a triangle mesh discretization of the boundary. The end result is an orthogonal direction field that can be sampled anywhere inside the mesh, with smooth variation and singular structure in the interior, even with a coarse boundary. We illustrate our computed frames on a number of challenging test geometries. Since the octahedral frame field problem is relatively new, we also contribute a thorough discussion of theoretical and practical challenges unique to this problem.
Co-Locating Style-Defining Elements on 3D Shapes
Authors: Hu Ruizhen , Li Wenchao , Kaick Oliver Van , Huang Hui , Averkiou Melinos , Cohen-Or Daniel , Zhang Hao
Published: April 2018

We introduce a method for
co-locating style-defining
elements over a set of 3D shapes. Our goal is to translate high-level style descriptions, such as “Ming” or “European” for furniture models, into
explicit
and
localized
regions over the geometric models that characterize each style. For each style, the set of style-defining elements is defined as the union of all the elements that are able to discriminate the style. Another property of the style-defining elements is that they are frequently occurring, reflecting shape characteristics that appear across multiple shapes of the same style. Given an input set of 3D shapes spanning multiple categories and styles, where the shapes are grouped according to their style labels, we perform a cross-category co-analysis of the shape set to learn and spatially locate a set of defining elements for each style. This is accomplished by first sampling a large number of candidate geometric elements and then iteratively applying feature selection to the candidates, to extract style-discriminating elements until no additional elements can be found. Thus, for each style label, we obtain sets of discriminative elements that together form the superset of defining elements for the style. We demonstrate that the co-location of style-defining elements allows us to solve problems such as style classification, and enables a variety of applications such as style-revealing view selection, style-aware sampling, and style-driven modeling for 3D shapes.
A Schur Complement Preconditioner for Scalable Parallel Fluid Simulation
Authors: Chu Jieyu , Zafar Nafees Bin , Yang Xubo
Published: April 2018

We present an algorithmically efficient and parallelized domain decomposition based approach to solving Poisson’s equation on irregular domains. Our technique employs the Schur complement method, which permits a high degree of parallel efficiency on multicore systems. We create a novel Schur complement preconditioner which achieves faster convergence, and requires less computation time and memory. This domain decomposition method allows us to apply different linear solvers for different regions of the flow. Subdomains with regular boundaries can be solved with an FFT-based Fast Poisson Solver. We can solve systems with 1,024
3
degrees of freedom, and demonstrate its use for the pressure projection step of incompressible liquid and gas simulations. The results demonstrate considerable speedup over preconditioned conjugate gradient methods commonly employed to solve such problems, including a multigrid preconditioned conjugate gradient method.
A Survey on NoSQL Stores
Authors: Davoudian Ali , Chen Liu , Liu Mengchi
Published: April 2018

Recent demands for storing and querying big data have revealed various shortcomings of traditional relational database systems. This, in turn, has led to the emergence of a new kind of complementary nonrelational data store, named as NoSQL. This survey mainly aims at elucidating the design decisions of NoSQL stores with regard to the four nonorthogonal design principles of distributed database systems: data model, consistency model, data partitioning, and the CAP theorem. For each principle, its available strategies and corresponding features, strengths, and drawbacks are explained. Furthermore, various implementations of each strategy are exemplified and crystallized through a collection of representative academic and industrial NoSQL technologies. Finally, we disclose some existing challenges in developing effective NoSQL stores, which need attention of the research community, application designers, and architects.
Selection and Sorting in the “Restore” Model
Authors: Chan Timothy M. , Munro J. Ian , Raman Venkatesh
Published: April 2018

We consider the classical selection and sorting problems in a model where the initial permutation of the input has to be
restored
after completing thecomputation. Such algorithms are useful for designing space-efficient algorithms, when one encounters subproblems that have to be solved by subroutines. It is important that these subroutines leave the array in its original state after they finish so that the computation can be properly resumed. Algorithms in this model can also be relevant for saving communication time, in case the data is distributed among several machines and would need to be copied to further machines for execution of the subroutine.

Although the requirement of the restoration is stringent compared to the classicalversions of the problems, this model is more relaxed than a read-only memory where the input elements are not allowed to be moved within the input array. We first show that for a sequence of
n
integers, selection (finding the median or more generally the
k
-th smallest element for a given
k
) can be done in
O
(
n
) time using
O
(lg
n
) words
1
of extra space in this model. In contrast, no linear-time selection algorithm is known that uses polylogarithmic space in the read-only memory model.

For sorting
n
integers in this model, we first present an
O
(
n
lg
n
)-time algorithm using
O
(lg
n
) words of extra space that outputs (in a write only tape) the given sequence in sorted order while restoring the order of the original input in the input tape. When the universe size
U
is polynomial in
n
, we give a faster
O
(
n
)-time algorithm (analogous to radix sort) that uses
O
(
n
ε
) words of extra space for an arbitrarily small constant ε > 0. More generally, we show how to match the time bound of any word-RAM integer sorting algorithms using
O
(
n
ε
) words of extra space. In sharp contrast, there is an Ω (
n
2
/
S
)-time lower bound for integer sorting using
O
(
S
) bits of space in the read-only memory model. Extension of our results to arbitrary input types beyond integers is not possible: for “indivisible” input elements, we can prove the same Ω (
n
2
/
S
) lower bound for sorting in our model. We also describe space-efficient algorithms to count the number of inversions in a given sequence in this model.

En route, we develop linear-time in-place algorithms to extract leading bits of the input array and to compress and decompress strings with low entropy; these techniques may be of independent interest.
Neuropilin-2 regulates airway inflammatory responses to inhaled lipopolysaccharide
Authors: Immormino Robert M. , Lauzier David C. , Nakano Hideki , Hernandez Michelle L. , Alexis Neil E. , Ghio Andrew J. , Tilley Stephen L. , Doerschuk Claire M. , Peden David B. , Cook Donald N. , Moran Timothy P.
Published: April 2018

Neuropilins are multifunctional receptors that play important roles in immune regulation. Neuropilin-2 (NRP2) is expressed in the lungs, but whether it regulates airway immune responses is unknown. Here, we report that Nrp2 is weakly expressed by alveolar macrophages (AMs) in the steady state but is dramatically upregulated following in vivo lipopolysaccharide (LPS) inhalation. Ex vivo treatment of human AMs with LPS also increased NRP2 mRNA expression and cell-surface display of NRP2 protein. LPS-induced Nrp2 expression in AMs was dependent upon the myeloid differentiation primary response 88 signaling pathway and the transcription factor NF-κB. In addition to upregulating display of NRP2 on the cell membrane, inhaled LPS also triggered AMs to release soluble NRP2 into the airways. Finally, myeloid-specific ablation of NRP2 resulted in increased expression of the chemokine (C-C motif) ligand 2 ( Ccl2) in the lungs and prolonged leukocyte infiltration in the airways following LPS inhalation. These findings suggest that NRP2 expression by AMs regulates LPS-induced inflammatory cell recruitment to the airways and reveal a novel role for NRP2 during innate immune responses in the lungs.
ICT Adoption Impact on Students’ Academic Performance: Evidence from Saudi Universities
Authors: Basri Wael Sh. , Alandejani Jehan A. , Almadani Feras M.
Published: April 2018

This study investigates and explores the adoption of information communication technology by the universities and the impact it makes on the university students’ academic performance. The study also examines the moderators’ effect of gender, GPA, and student majors on the relationship between ICT and academic achievement. By using a quantitative research approach and a sample size of 1000 students, data were collected about the ICT adoption in universities and the relative performance of students belonging to four Saudi universities. Structure equation modelling was chosen to determine the validity of the research model. The Analysis of Moment Structures (AMOS), specially used for structural equation modelling and path analysis, was used as the research tool. The findings reveal that there exists a relationship between ICT adoption and academic performance in a conservative environment. An additional finding also stated that ICT adoption resulted in the improvement of the performance of female students more than the male. However, students’ IT major was found to be making no impact on students’ academic achievement. A discussion of findings, limitations, and suggestions for future research has been provided in the study. Finally, it also provides implications of the current study to the existing knowledge.
Diagnosis and Surgical Management of Congenital Intranasal Teratoma in a Newborn: A Rare Case Report
Authors: Yeo W. X. , Tan K. K.
Published: April 2018

Teratomas are the most common germ cell tumors of childhood. Head and neck teratomas, however, account for less than five percent of all teratomas. Considered rare at an incidence of 1 in 20,000 to 40,000 live births, they may occur in the cervical region, nasopharynx, brain, orbit, or oropharynx. Teratoma presenting as an isolated intranasal mass is extremely rare. In this report, we describe a case of a mature teratoma arising from the roof of the nasal cavity presenting as an isolated intranasal mass, the first of its kind from our literature review. The tumor was resected endoscopically with no recurrence detected.
Anti‐Inflammatory Activity of Marine Ovothiol A in an In Vitro Model of Endothelial Dysfunction Induced by Hyperglycemia
Authors: Castellano Immacolata , Di Tomo Pamela , Di Pietro Natalia , Mandatori Domitilla , Pipino Caterina , Formoso Gloria , Napolitano Alessandra , Palumbo Anna , Pandolfi Assunta
Published: April 2018

Chronic hyperglycemia is associated with oxidative stress and vascular inflammation, both leading to endothelial dysfunction and cardiovascular disease that can be weakened by antioxidant/anti‐inflammatory molecules in both healthy and diabetic subjects. Among natural molecules, ovothiol A, produced in sea urchin eggs to protect eggs/embryos from the oxidative burst at fertilization and during development, has been receiving increasing interest for its use as an antioxidant. Here, we evaluated the potential antioxidative/anti‐inflammatory effect of purified ovothiol A in an in vitro cellular model of hyperglycemia‐induced endothelial dysfunction employing human umbilical vein endothelial cells (HUVECs) from women affected by gestational diabetes (GD) and from healthy mothers. Ovothiol A was rapidly taken up by both cellular systems, resulting in increased glutathione values in GD‐HUVECs, likely due to the formation of reduced ovothiol A. In tumor necrosis factor‐α‐stimulated cells, ovothiol A induced a downregulation of adhesion molecule expression and decrease in monocyte‐HUVEC interaction. This was associated with a reduction in reactive oxygen and nitrogen species and an increase in nitric oxide bioavailability. These results point to the potential antiatherogenic properties of the natural antioxidant ovothiol A and support its therapeutic potential in pathologies related to cardiovascular diseases associated with oxidative/inflammatory stress and endothelial dysfunction.
Recognizing Continuous and Discontinuous Adverse Drug Reaction Mentions from Social Media Using LSTM‐CRF
Authors: Tang Buzhou , Hu Jianglu , Wang Xiaolong , Chen Qingcai
Published: April 2018

Social media in medicine, where patients can express their personal treatment experiences by personal computers and mobile devices, usually contains plenty of useful medical information, such as adverse drug reactions (ADRs); mining this useful medical information from social media has attracted more and more attention from researchers. In this study, we propose a deep neural network (called LSTM‐CRF) combining long short‐term memory (LSTM) neural networks (a type of recurrent neural networks) and conditional random fields (CRFs) to recognize ADR mentions from social media in medicine and investigate the effects of three factors on ADR mention recognition. The three factors are as follows: (1) representation for continuous and discontinuous ADR mentions: two novel representations, that is, “BIOHD” and “Multilabel,” are compared; (2) subject of posts: each post has a subject (i.e., drug here); and (3) external knowledge bases. Experiments conducted on a benchmark corpus, that is, CADEC, show that LSTM‐CRF achieves better F‐score than CRF; “Multilabel” is better in representing continuous and discontinuous ADR mentions than “BIOHD”; both subjects of comments and external knowledge bases are individually beneficial to ADR mention recognition. To the best of our knowledge, this is the first time to investigate deep neural networks to mine continuous and discontinuous ADRs from social media.
Main Lobe Control of a Beam Tilting Antenna Array Laid on a Deformable Surface
Authors: Mansutti Giulia , Rigobello Francesco , Asif Sajid M. , Khan Muhammad S. , Capobianco Antonio-D. , Galtarossa Andrea
Published: April 2018

The projection method (PM) is a simple and low-cost pattern recovery technique that already proved its effectiveness in retrieving the radiation properties of different types of arrays that change shape in time. However, when dealing with deformable beam-tilting arrays, this method requires to compute new compensating phase shifts every time that the main lobe is steered, since these shifts depend on both the deformation geometry and the steering angle. This tight requirement causes additional signal processing and complicates the prediction of the array behavior, especially if the deformation geometry is not a priori known: this can be an issue since the PM is mainly used for simple and low-cost systems. In this letter, we propose a simplification of this technique for beam-tilting arrays that requires only basic signal processing. In fact the phase shifts that we use are the sum of two components: one can be directly extracted from strain sensor data that measure surface deformation and the other one can be precomputed according to basic antenna theory. The effectiveness of our approach has been tested on two antennas: a 4 × 4 array (trough full-wave simulations and measurements) and on an 8 × 8 array (trough full-wave simulations) placed on a doubly wedge-shaped surface with a beam tilt up to 40 degrees.
Analysis of Association of Genetic Markers in the LUZP2 and FBXO40 Genes with the Normal Variability in Cognitive Performance in the Elderly
Authors: Stepanov Vadim , Vagaitseva Kseniya , Bocharova Anna , Marusin Andrey , Markova Valentina , Minaycheva Larisa , Makeeva Oksana
Published: April 2018

Cognitive performance is an important endophenotype for various neurodegenerative and neuropsychiatric traits. In the present study two genetic variants in the leucine-zipper protein (LUZP2) and the F-box 40 protein (FBXO40) genes, previously reported to be genome-wide significant for Alzheimer’s diseases and schizophrenia, were examined for an association with cognitive abilities in normal elderly from the Russian population. Rs1021261 in the LUZP2 and rs3772130 in the FBXO40 were genotyped by multiplex PCR and MALDI-TOF mass spectrometry in a sample of 708 normal elderly subjects tested for cognitive performance using the Montreal Cognitive Assessment (MoCA). Association of genetic variability with the MoCA scores was estimated by parametric and nonparametric analysis of variance and by the frequency comparison between upper and lower quartiles of MoCA distribution. Significantly higher frequency of “TT” genotype of rs1021261 in the LUZP2 gene as well as “A” allele and “AA” genotype of rs3772130 in the FBXO40 gene was found in a subsample of individuals with the MoCA score less than 20 comparing to the fourth quartile’s subsample (MoCA > 25). The data of the present study suggests that genetic variability in the LUZP2 and FBXO40 loci associated with neurodegenerative and neuropsychiatric diseases is also contributed to the normal variability in cognitive performance in the elderly.
Design of a Novel Miniaturized Frequency Selective Surface Based on 2.5‐Dimensional Jerusalem Cross for 5G Applications
Authors: Zhao Peng , Zhang Yihang , Sun Rongrong , Zhao Wen-Sheng , Hu Yue , Wang Gaofeng
Published: April 2018

A compact frequency selective surface (FSS) for 5G applications has been designed based on 2.5‐dimensional Jerusalem cross. The proposed element consists of two main parts: the successive segments of the metal traces placed alternately on the two surfaces of the substrate and the vertical vias connecting traces. Compared with previous published two‐dimensional miniaturized elements, the transmission curves indicate a significant size reduction (1/26 wavelengths at the resonant frequency) and exhibit good angular and polarization stabilities. Furthermore, a general equivalent circuit model is established to provide direct physical insight into the operating principle of this FSS. A prototype of the proposed FSS has been fabricated and measured, and the results validate this design.
DUOX1 Silencing in Mammary Cell Alters the Response to Genotoxic Stress
Authors: Fortunato Rodrigo S. , Gomes Luciana R. , Munford Veridiana , Pessoa Carolina Fittipaldi , Quinet Annabel , Hecht Fabio , Kajitani Gustavo S. , Milito Cristiane Bedran , Carvalho Denise P. , Menck Carlos Frederico Martins
Published: April 2018

DUOX1 is an H2O2‐generating enzyme related to a wide range of biological features, such as hormone synthesis, host defense, cellular proliferation, and fertilization. DUOX1 is frequently downregulated in lung and liver cancers, suggesting a tumor suppressor role for this enzyme. Here, we show that DUOX1 expression is decreased in breast cancer cell lines and also in breast cancers when compared to the nontumor counterpart. In order to address the role of DUOX1 in breast cells, we stably knocked down the expression of DUOX1 in nontumor mammary cells (MCF12A) with shRNA. This led to higher cell proliferation rates and decreased migration and adhesion properties, which are typical features for transformed cells. After genotoxic stress induced by doxorubicin, DUOX1‐silenced cells showed reduced IL‐6 and IL‐8 secretion and increased apoptosis levels. Furthermore, the cell proliferation rate was higher in DUOX1‐silenced cells after doxorubicin medication in comparison to control cells. In conclusion, we demonstrate here that DUOX1 is silenced in breast cancer, which seems to be involved in breast carcinogenesis.
Brain State Decoding Based on fMRI Using Semisupervised Sparse Representation Classifications
Authors: Zhang Jing , Zhang Chuncheng , Yao Li , Zhao Xiaojie , Long Zhiying
Published: April 2018

Multivariate classification techniques have been widely applied to decode brain states using functional magnetic resonance imaging (fMRI). Due to variabilities in fMRI data and the limitation of the collection of human fMRI data, it is not easy to train an efficient and robust supervised-learning classifier for fMRI data. Among various classification techniques, sparse representation classifier (SRC) exhibits a state-of-the-art classification performance in image classification. However, SRC has rarely been applied to fMRI-based decoding. This study aimed to improve SRC using unlabeled testing samples to allow it to be effectively applied to fMRI-based decoding. We proposed a semisupervised-learning SRC with an average coefficient (semiSRC-AVE) method that performed the classification using the average coefficient of each class instead of the reconstruction error and selectively updated the training dataset using new testing data with high confidence to improve the performance of SRC. Simulated and real fMRI experiments were performed to investigate the feasibility and robustness of semiSRC-AVE. The results of the simulated and real fMRI experiments showed that semiSRC-AVE significantly outperformed supervised learning SRC with an average coefficient (SRC-AVE) method and showed better performance than the other three semisupervised learning methods.
Antifibrogenic Influence of Mentha piperita L. Essential Oil against CCl4‐Induced Liver Fibrosis in Rats
Authors: Ogaly Hanan A. , Eltablawy Nadia A. , Abd-Elsalam Reham M.
Published: April 2018

Essential oils of some aromatic plants provide an effective nonmedicinal option to control liver fibrosis. Mentha piperita L. essential oil (MPEO) have been reported to possess protective effects against hepatotoxicity. However, its effect against liver fibrosis remains unknown. The present study investigated the antifibrogenic potential of MPEO and its underlying mechanisms. Forty male rats divided into 4 groups were used: group 1 served as normal control, group 2 (liver fibrosis) received CCl4 (2.5 mL/kg, IP, twice weekly) for 8 weeks, group 3 concurrently received CCl4 plus MPEO (50 mg/kg, IP, daily, from the 3rd week), and group 4 received MPEO only. MPOE significantly improved the liver injury markers, lipid peroxidation (LPO), antioxidant capacity, CYP2E1 gene expressionand liver histology. Furthermore, MPOE ameliorated liver fibrosis as evidenced by the reduced expression of desmin, α‐smooth muscle actin (α‐SMA), transforming growth factor‐β1 (TGF‐β1), and SMAD3 proteins. In addition, MPOE counteracted the p53 upregulation induced by CCl4 at both mRNA and protein levels. In conclusion, MPOE could effectively attenuate hepatic fibrosis mainly through improving the redox status, suppressing p53 and subsequently modulating TGF‐β1 and SMAD3 protein expression. These data promote the use of MPOE as a promising approach in antifibrotic therapy.
Electroweak Phase Transitions in Einstein’s Static Universe
Authors: Gogberashvili M.
Published: April 2018

We suggest using Einstein’s static universe metric for the metastable state after reheating, instead of the Friedman-Robertson-Walker spacetime. In this case, strong static gravitational potential leads to the effective reduction of the Higgs vacuum expectation value, which is found to be compatible with the Standard Model first-order electroweak phase transition conditions. Gravity could also increase the CP-violating effects for particles that cross the new phase bubble walls and thus is able to lead to the successful electroweak baryogenesis scenario.
Moving Unstable Particles and Special Relativity
Authors: Stefanovich Eugene V.
Published: April 2018

In Poincaré-Wigner-Dirac theory of relativistic interactions, boosts are dynamical. This means that, just like time translations, boost transformations have a nontrivial effect on internal variables of interacting systems. In this respect, boosts are different from space translations and rotations, whose actions are always universal, trivial, and interaction-independent. Applying this theory to unstable particles viewed from a moving reference frame, we prove that the decay probability cannot be invariant with respect to boosts. Different moving observers may see different internal compositions of the same unstable particle. Unfortunately, this effect is too small to be noticeable in modern experiments.