bluuebunny/crossref_metadata_2025 huggingface dataset:
The Comparison of Aerodynamic Performance Data Acquired From Thermal Measurements and a Torquemeter on a Compressor Impeller
Authors: Smith Natalie R. , Allison Timothy C. , Wilkes Jason C. , Clarke Christopher , Cave Michael
Published: October 2018

Full-thermal heat-soak of machinery is vital for acquiring accurate aerodynamic performance data, but this process often requires significant testing time to allow all facility components to reach a steady-state temperature. Even still, there is the potential for heat loss in a well-insulated facility, and this can lead to inaccurate results. The implementation of a torquemeter to calculate performance metrics, such as isentropic efficiency, has two potential advantages: (1) the method is not susceptible to effects due to thermal heat loss in the facility, and (2) a torquemeter directly measures actual torque, and thus work, input, which eliminates the need to fully heat-soak to measure the actual enthalpy rise of the gas. This paper presents a comparison of aerodynamic performance metrics calculated both from data acquired with thermal measurements as well as from a torquemeter.

These tests were conducted over five speedlines for a shrouded impeller in the Southwest Research Institute Single Stage Test Rig facility. Isentropic efficiency calculated from the torquemeter was approximately 1–2 efficiency points lower than the isentropic efficiency based on thermal measurements. This corresponds to approximately 0.5–1 °C in heat loss in the discharge collector and piping. Furthermore, observations from three full-thermal heat-soak points indicate the significant difference in time required to reach steady-state performance within measurement uncertainty tolerances between the torque-based and thermal-based methods. This comparison, while largely suspected, has not yet been studied in previous publications.
Gain-Scheduling Attitude Control for Complex Spacecraft Based on HOSVD
Authors: Lei Bingyao , Shi Peng , Wen Changxuan , Zhao Yushan
Published: October 2018

In this paper, a robust gain-scheduling attitude control scheme for spacecrafts with large rotational appendages is proposed. First, by introducing the higher-order singular value decomposition (HOSVD) method, a polytopic linear parameter varying (LPV) model with a family of weighting coefficients is developed based on the kinetics of a flexible spacecraft. This model eliminates the need of verifying all the gridding points, which is required in conventional controller synthesis process, and reduces the calculation complexity. Second, a generalized plant is derived to guarantee both the system robust stability and the tracking performances. Based on the LPV control theory, a less conservative controller synthesis condition for the polytopic LPV system is deduced. With an online tuning unit, the convex combination of every vertex controller is obtained. For control implementation, the present scheduling parameter is taken as an input for the tuning unit. Numerical results demonstrate the effectiveness and efficiency of the proposed control scheme.
Development and Use of Machine-Learnt Algebraic Reynolds Stress Models for Enhanced Prediction of Wake Mixing in Low-Pressure Turbines
Authors: Akolekar H. D. , Weatheritt J. , Hutchins N. , Sandberg R. D. , Laskowski G. , Michelassi V.
Published: October 2018

Nonlinear turbulence closures were developed that improve the prediction accuracy of wake mixing in low-pressure turbine (LPT) flows. First, Reynolds-averaged Navier–Stokes (RANS) calculations using five linear turbulence closures were performed for the T106A LPT profile at isentropic exit Reynolds numbers 60,000 and 100,000. None of these RANS models were able to accurately reproduce wake loss profiles, a crucial parameter in LPT design, from direct numerical simulation (DNS) reference data. However, the recently proposed kv2¯ω transition model was found to produce the best agreement with DNS data in terms of blade loading and boundary layer behavior and thus was selected as baseline model for turbulence closure development. Analysis of the DNS data revealed that the linear stress–strain coupling constitutes one of the main model form errors. Hence, a gene-expression programming (GEP) based machine-learning technique was applied to the high-fidelity DNS data to train nonlinear explicit algebraic Reynolds stress models (EARSM), using different training regions. The trained models were first assessed in an a priori sense (without running any RANS calculations) and showed much improved alignment of the trained models in the region of training. Additional RANS calculations were then performed using the trained models. Importantly, to assess their robustness, the trained models were tested both on the cases they were trained for and on testing, i.e., previously not seen, cases with different flow features. The developed models improved prediction of the Reynolds stress, turbulent kinetic energy (TKE) production, wake-loss profiles, and wake maturity, across all cases.
The Effect of Charge and Mechanical Loading on Antibody Diffusion Through the Articular Surface of Cartilage
Authors: DiDomenico Chris D. , Bonassar Lawrence J.
Published: October 2018

Molecular transport of osteoarthritis (OA) therapeutics within articular cartilage is influenced by many factors, such as solute charge, that have yet to be fully understood. This study characterizes how solute charge influences local diffusion and convective transport of antibodies within the heterogeneous cartilage matrix. Three fluorescently tagged solutes of varying isoelectric point (pI) (4.7–5.9) were tested in either cyclic or passive cartilage loading conditions. In each case, local diffusivities were calculated based on local fluorescence in the cartilage sample, as observed by confocal microscopy. In agreement with past research, local solute diffusivities within the heterogeneous cartilage matrix were highest around 200–275 μm from the articular surface, but 3–4 times lower at the articular surface and in the deeper zones of the tissue. Transport of all 150 kDa solutes was significantly increased by the application of mechanical loading at 1 Hz, but local transport enhancement was not significantly affected by changes in solute isoelectric point. More positively charged solutes (higher pI) had significantly higher local diffusivities 200–275 μm from the tissue surface, but no other differences were observed. This implies that there are certain regions of cartilage that are more sensitive to changes in solute charge than others, which could be useful for future development of OA therapeutics.
Uncertainty Considerations for Nonlinear Dynamics of a Class of MEMS Switches Undergoing Tip Contact Bouncing
Authors: Bognash Mohamed , Asokanthan Samuel F.
Published: October 2018

Batch fabrication processes used to produce micro-electro-mechanical systems (MEMS) are prone to uncertainties in the system geometrical and contact parameters as well as material properties. However, since the common design method for these systems is typically based on precise deterministic assumptions, it is necessary to get more insight into their variations. To this end, understanding the influences of uncertainties accompanied by these processes on the system performance and reliability is warranted. The present paper focuses on predictions of uncertainty measures for MEMS switches based on the transient dynamic response, in particular, the bouncing behavior. To understand and quantify the influence of pertinent parameters on the bouncing effects, suitable mathematical model that captures the bouncing dynamics as well as the forces that are dominant at this micron scale are employed. Measure of performance in terms of second-order statistics is performed, particularly for the beam as well as beam tip parameters since excessive tip bounce is known to degrade switch performance. Thus, the present study focusses on the influence of uncertainties in the beam tip geometry parameters such as beam tip length/width as well as contact asperity variables such as the area asperity density and the radius of asperities. In addition to beam tip parameters, this study quantifies the effects of uncertainties in Young's modulus, beam thickness as well as actuation voltage. These influences on significant switch performance parameters such as initial contact time and maximum bounce height have been quantified in the presence of interactive system nonlinearities.
Study of Dynamic Model of Helical/Herringbone Planetary Gear System With Friction Excitation
Authors: Hou Shaoshuai , Wei Jing , Zhang Aiqiang , Lim Teik C. , Zhang Chunpeng
Published: October 2018

Tooth friction is unavoidable and changes periodically in gear engagement. Friction excitation is an important excitation source of a gear transmission system. They are different than the friction coefficients of any two points on the same contact line of a helical/herringbone gear. In order to obtain the influence of the friction excitation on the dynamic response of a helical/herringbone planetary gear system, a method that uses piecewise solution and then summing them to analyze the friction force and frictional torque of tooth surfaces is proposed. Then, the friction coefficient is obtained based on the mixed elastohydrodynamic lubrication (EHL) theory. A dynamic model of a herringbone planetary gear system is established considering the friction, mesh stiffness, and meshing error excitation by the node finite element method. The influence of friction excitation on the dynamic response of the herringbone planetary gear is studied under different working conditions. The results show that friction excitation has a great influence on the vibration acceleration of the sun and planetary gear. However, the effect on the radial and tangential vibration acceleration of a planetary gear is the opposite. In addition, the friction excitation has a slight effect on the meshing force.
Prediction Algorithm for WEDM Arced Path Errors Based on Spark Variable Gap and Nonuniform Spark Distribution Models
Authors: Abyar Hamid , Abdullah Amir , Akbarzadeh Abdolhamid
Published: October 2018

Wire electrical discharge machining (WEDM) is a demanding high-precision process for machining of hard-to-machine materials. The main issue is manufacturing errors in shape and radius of small arcs generation. In this paper, a novel model about spark variable gap sizes and nonuniform spark distribution around the wire on arced path machining is first theoretically developed using spark angle domain and WEDM dynamic analysis. Applying spark-force distributed around the wire and resulting wire deflection are estimated by the WEDM conditions influenced by plasma channel specifications, discharge frequency, wire guide clearance, wire tension, and arc radius. Total theoretical arced machining errors including wire deflection and spark gap size variation around the wire interface are calculated based on the proposed model. In addition, machining errors of straight and small arced paths are experimentally analyzed under variation of WEDM influential parameters including discharge frequency, arced path radius (150, 300 and 450 μm), and wire tension through the statistical full factorial. Comparison of the results for different sets of variable parameters shows that the theoretical values of the arced machining errors can be consistent with the experimental one by a coefficient which depends on the machining conditions and the WED machine type. Finally, based on the theoretical and experimental results, a theoretical algorithm and an operational method with mean accuracy of 84.8% are proposed for predicting and compensating the errors of WEDM on the arced paths. Findings of this research can be used in high-accurate WEDM applications and industries.
Discovering Sequenced Origami Folding Through Nonlinear Mechanics and Topology Optimization
Authors: Gillman Andrew S. , Fuchi Kazuko , Buskohl Philip R.
Published: October 2018

Origami folding provides a novel method to transform two-dimensional (2D) sheets into complex functional structures. However, the enormity of the foldable design space necessitates development of algorithms to efficiently discover new origami fold patterns with specific performance objectives. To address this challenge, this work combines a recently developed efficient modified truss finite element model with a ground structure-based topology optimization framework. A nonlinear mechanics model is required to model the sequenced motion and large folding common in the actuation of origami structures. These highly nonlinear motions limit the ability to define convex objective functions, and parallelizable evolutionary optimization algorithms for traversing nonconvex origami design problems are developed and considered. The ability of this framework to discover fold topologies that maximize targeted actuation is verified for the well-known “Chomper” and “Square Twist” patterns. A simple twist-based design is also discovered using the verified framework. Through these case studies, the role of critical points and bifurcations emanating from sequenced deformation mechanisms (including interplay of folding, facet bending, and stretching) on design optimization is analyzed. In addition, the performance of both gradient and evolutionary optimization algorithms are explored, and genetic algorithms (GAs) consistently yield solutions with better performance given the apparent nonconvexity of the response-design space.
Unified Stiffness Characterization of Nonlinear Compliant Shell Mechanisms
Authors: Leemans Joost R. , Kim Charles J. , van de Sande Werner W .P. J. , Herder Just L.
Published: October 2018

Compliant shell mechanisms utilize spatially curved thin-walled structures to transfer or transmit force, motion, or energy through elastic deformation. To design spatial mechanisms, designers need comprehensive nonlinear characterization methods, while the existing methods fall short of meaningful comparisons between rotational and translational degrees-of-freedom. This paper presents two approaches, both of which are based on the principle of virtual loads and potential energy, utilizing properties of screw theory, Plücker coordinates, and an eigen-decomposition. This leads to two unification lengths that can be used to compare and visualize all six degrees-of-freedom directions and magnitudes in a nonarbitrary, physically meaningful manner for mechanisms exhibiting geometrically nonlinear behavior.
Design and Modeling of a Variable Thickness Flexure Pivot
Authors: Yang Miao , Du Zhijiang , Dong Wei , Sun Lining
Published: October 2018

Flexure pivots are frequently applied in long stroke compliant mechanisms to transmit motion continuously. To improve the motion accuracy, a kind of variable thickness flexure pivot (VTFP) is proposed in this paper. A nonlinear beam element is proposed by utilizing the corotational approach to model the static response of the VTFP under end loads. Finite element analysis and experimental tests are carried out to verify the effectiveness of the modeling method. Based on the static deformation model, the motion range, the rotation stiffness, the center shift, and the variation of the center shift under axial force of the VTFP are investigated. The results show that the VTFP has better motion accuracy and better ability to resist axial force compared with the conventional flexure pivot.
Second Law Analysis of Flow in a Circular Pipe With Uniform Suction and Magnetic Field Effects
Authors: Nagaraju G. , Jangili Srinivas , Ramana Murthy J. V. , Bég O. A. , Kadir A.
Published: October 2018

The present paper investigates analytically the two-dimensional heat transfer and entropy generation characteristics of axisymmetric, incompressible viscous fluid flow in a horizontal circular pipe. The flow is subjected to an externally applied uniform suction across the wall in the normal direction and a constant magnetic field. Constant wall temperature is considered as the thermal boundary condition. The reduced Navier–Stokes equations in a cylindrical coordinate system are solved to obtain the velocity and temperature distributions. The velocity distributions are expressed in terms of stream function and the solution is obtained using the homotopy analysis method (HAM). Validation with earlier nonmagnetic solutions in the literature is incorporated. The effects of various parameters on axial and radial velocities, temperature, axial and radial entropy generation numbers, and axial and radial Bejan numbers are presented graphically and interpreted at length. Streamlines, isotherms, pressure, entropy generation number, and Bejan number contours are also visualized. Increasing magnetic body force parameter shifts the peak of the velocity curve near to the axis, whereas it accelerates the radial flow. The study is relevant to thermodynamic optimization of magnetic blood flows and electromagnetic industrial flows featuring heat transfer.
Evidence from Mutational Analysis for a Single Transmembrane Substrate Binding Site in the Histidine ATP-Binding Cassette Transporter of Salmonella enterica Serovar Typhimurium
Authors: Heuveling Johanna , Landmesser Heidi , Schneider Erwin
Published: October 2018

Canonical ATP-binding cassette (ABC) importers are major players in the translocation of numerous nutrients, vitamins, and growth factors to the cytoplasm of prokaryotes. Moreover, some ABC importers have been identified as virulence factors in bacterial pathogenesis. Thus, a full understanding of their mode of action is considered a prerequisite, among others, for the development of novel antibacterial drugs. However, mainly owing to the lack of structural information, the knowledge of the chemical nature and number of substrate binding sites formed by the transmembrane subunits of ABC importers is scarce. Here, we provide evidence from mutational analyses that, in contrast to homologous homodimeric systems, the heterodimeric histidine transporter of
Salmonella enterica
serovar Typhimurium is liganding only one substrate molecule between its transmembrane subunits, HisM and HisQ.
Comprehensive Characterization of
Toxoplasma
Acyl Coenzyme A-Binding Protein TgACBP2 and Its Critical Role in Parasite Cardiolipin Metabolism
Authors: Fu Yong , Cui Xia , Fan Sai , Liu Jing , Zhang Xiao , Wu Yihan , Liu Qun
Published: October 2018

Toxoplasma gondii
is one of the most successful human parasites, infecting nearly one-third of the total world population.
T. gondii
tachyzoites residing within parasitophorous vacuoles (PVs) can acquire fatty acids both via salvage from host cells and via
de novo
synthesis pathways for membrane biogenesis. However, although fatty acid fluxes are known to exist in this parasite, how fatty acids flow through
Toxoplasma
lipid metabolic organelles, especially mitochondria, remains unknown. In this study, we demonstrated that
Toxoplasma
expresses an active ankyrin repeat containing protein TgACBP2 to coordinate cardiolipin metabolism. Specifically, HMA acquisition resulting from heterologous functional expression of MAF1 rescued growth and lipid metabolism defects in ACBP2-deficient type II parasites, manifesting the complementary role of host mitochondria in parasite cardiolipin metabolism. This work highlights the importance of TgACBP2 in parasite cardiolipin metabolism and provides evidence for metabolic association of host mitochondria with
T. gondii
.
HIV-1 Vpr Reprograms CLR4
DCAF1
E3 Ubiquitin Ligase to Antagonize Exonuclease 1-Mediated Restriction of HIV-1 Infection
Authors: Yan Junpeng , Shun Ming-Chieh , Hao Caili , Zhang Yi , Qian Juan , Hrecka Kasia , DeLucia Maria , Monnie Christina , Ahn Jinwoo , Skowronski Jacek
Published: October 2018

HIV-1 polymerase reverse transcribes the viral RNA genome into imperfectly double-stranded proviral DNA, containing gaps and flaps, for integration into the host cell chromosome. HIV-1 reverse transcripts share characteristics with cellular DNA replication intermediates and are thought to be converted into fully double-stranded DNA by cellular postreplication DNA repair enzymes. Therefore, the finding that the HIV-1 accessory protein Vpr antagonizes select postreplication DNA repair enzymes that can process HIV-1 reverse transcripts has been surprising. Here, we show that one such Vpr-antagonized enzyme, exonuclease 1, inhibits HIV-1 replication in T cells. We identify exonuclease 1 as a member of a new class of HIV-1 restriction factors in T cells and propose that certain modes of DNA “repair” inhibit HIV-1 infection.
Phenotypic Variability Correlates with Clinical Outcome in
Cryptococcus
Isolates Obtained from Botswanan HIV/AIDS Patients
Authors: Fernandes Kenya E. , Brockway Adam , Haverkamp Miriam , Cuomo Christina A. , van Ogtrop Floris , Perfect John R. , Carter Dee A.
Published: October 2018

Cryptococcosis results in hundreds of thousands of deaths annually, predominantly in sub-Saharan Africa.
Cryptococcus
is an encapsulated yeast, and during infection, cells have the capacity for substantial morphological changes, including capsule enlargement and shedding and variations in cell shape and size. In this study, we examined 70
Cryptococcus
isolates causing meningitis in HIV/AIDS patients in Botswana in order to look for associations between phenotypic variation and clinical symptoms. Four variant phenotypes were seen across strains: giant cells of ≥15 µm, micro cells of ≤1 µm, shed extracellular capsule, and irregularly shaped cells. We found that “large” and “small” phenotypes were associated with differing disease symptoms, indicating that their production may be important during the disease process. Overall, our study indicates that
Cryptococcus
strains that can switch on cell types under different situations may be more able to sustain infection and resist the host response.
Existing Climate Change Will Lead to Pronounced Shifts in the Diversity of Soil Prokaryotes
Authors: Ladau Joshua , Shi Yu , Jing Xin , He Jin-Sheng , Chen Litong , Lin Xiangui , Fierer Noah , Gilbert Jack A. , Pollard Katherine S. , Chu Haiyan
Published: October 2018

There have been many studies highlighting how plant and animal communities lag behind climate change, causing extinction and diversity debts that will slowly be paid as communities equilibrate. By virtue of their short generation times and dispersal abilities, soil bacteria might be expected to respond to climate change quickly and to be effectively in equilibrium with current climatic conditions. We found strong evidence to the contrary in Tibet and North America. These findings could significantly improve understanding of climate impacts on soil microbial communities.
First-principles investigation of activity and solubility of Si in Mo solid solution
Authors: Sun S. P. , Zhu J. L. , Gu S. , Wang H. J. , Jiang Y. , Yi D. Q.
Published: October 2018

The activity and solubility of Si in Mo solid solution were studied by the first-principles calculations and quasi-harmonic approximation. The lattice constants, bulk modulus, and formation enthalpies of Mo-Si intermetallics were investigated, and the thermodynamic properties of Mo were also calculated. The Si activity coefficient [Formula: see text] is approximately 10[Formula: see text] at 100 K, while it increases by about 15 orders of magnitude over the investigated temperature range (100–2000 K). It is clear that Si activity coefficient in Mo solid solution increased rapidly with the increasing temperature, which should be ascribed to the Si–Mo interaction being evidently stronger than Mo–Mo interaction. According to the calculated thermodynamic properties, the solubility curve of Si in Mo solid solution was also predicted. The solubility limit of Si in Mo solid solution is [Formula: see text]5.5 at.%, which agrees well with the other experiment and assessed results.
Vibration Suppression of a Nonlinear Fluid-Conveying Pipe Under Harmonic Foundation Displacement Excitation Via Nonlinear Energy Sink
Authors: Zhao Xiao-Ying , Zhang Ye-Wei , Ding Hu , Chen Li-Qun
Published: October 2018

In this paper, the vibration suppression mechanism of a nonlinear fluid pipe via nonlinear energy sink (NES) is studied for the first time. The fluid pipe is simply supported under harmonic foundation excitation. The complexification-averaging method combined with the arc-length continuation method is used to predict the response of the system. The analytical solution is supported by the numerical result. The trend of interaction between liquid speed and NES parameters are investigated by comparison of parameters optimization. It is especially pointed out that the change of stiffness has a very complicated influence on the response. The parameters optimization is investigated at the resonance frequency. It is noted that the liquid speed has an important effect on the vibration suppression of the fluid pipe. Besides, the system is evaluated from the point of view of energy. The distribution of the input energy is calculated and the instantaneous transaction of the energy is examined by considering the energy transaction measure (ETM). The numerical simulations demonstrate that the target energy transfer (TET) leads to a very efficient vibration suppression.
A Finite Element Method for Dielectric Elastomers Affected by Viscoelasticity and Current Leakage
Authors: Foo Choon Chiang , Liu Jun , Zhang Zhi-Qian
Published: October 2018

Dissipative processes such as viscoelasticity and current leakage are known to affect the electromechanical performance of dielectric elastomers. In this work, we describe a constitutive theory that couples electrostatics, large deformation, viscoelasticity and current leakage. We also implement this model in a commercial finite element solver ABAQUS by developing new user-defined elements. The method is used to study the effect of viscoelasticity and current leakage on the behavior of dielectric elastomers. Our finite element implementation will serve as a simulation platform to guide the design of practical dielectric elastomer transducers.
A Game Theoretic Model for the Formation of Navigable Small-World Networks—The Tradeoff between Distance and Reciprocity
Authors: Yang Zhi , Chen Wei
Published: October 2018

Kleinberg proposed a family of small-world networks to explain the navigability of large-scale real-world social networks. However, the underlying mechanism that drives real networks to be navigable is not yet well understood. In this article, we present a game theoretic model for the formation of navigable small-world networks. We model the network formation as a game called the
Distance-Reciprocity Balanced (DRB)
game in which people seek for both high reciprocity and long-distance relationships. We show that the game has only two Nash equilibria: One is the navigable small-world network, and the other is the random network in which each node connects with each other node with equal probability, and any other network state can reach the navigable small world via a sequence of best-response moves of nodes. We further show that the navigable small-world equilibrium is very stable—(a) no collusion of any size would benefit from deviating from it; and (b) after an arbitrary deviations of a large random set of nodes, the network would return to the navigable small world as soon as every node takes one best-response step. In contrast, for the random network, a small group collusion or random perturbations is guaranteed to bring the network out of the random-network equilibrium and move to the navigable network as soon as every node takes one best-response step. Moreover, we show that navigable small-world equilibrium has much better social welfare than the random network, and we provide the price-of-anarchy and price-of-stability results of the game. Our empirical evaluation further demonstrates that the system always converges to the navigable network even when limited or no information about other players’ strategies is available, and the DRB game simulated on real-world networks leads to navigability characteristic that is very close to that of the real networks, even though the real-world networks have non-uniform population distributions different from Kleinberg’s small-world model. Our theoretical and empirical analyses provide important new insight on the connection between distance, reciprocity, and navigability in social networks.
Constructing a High-Dimensional
k
NN-Graph Using a Z-Order Curve
Authors: Sieranoja Sami , Fränti Pasi
Published: October 2018

Although many fast methods exist for constructing a
k
NN-graph for low-dimensional data, it is still an open question how to do it efficiently for high-dimensional data. We present a new method to construct an approximate
k
NN-graph for medium- to high-dimensional data. Our method uses one-dimensional mapping with a Z-order curve to construct an initial graph and then continues to improve this using neighborhood propagation. Experiments show that the method is faster than the compared methods with five different benchmark datasets, the dimensionality of which ranges from 14 to 784. Compared to a brute-force approach, the method provides a speedup between 12.7:1 and 414.2:1 depending on the dataset. We also show that errors in the approximate
k
NN-graph originate more likely from outlier points; and, it can be detected during runtime, which points are likely to have errors in their neighbors.
ACM SIGAI activity report
Authors: Koenig Sven , Das Sanmay , Paradis Rosemary , Dickerson John , Gil Yolanda , Guo Katherine , Kuipers Benjamin , Ma Hang , Mattei Nicholas , McGovern Amy , Medsker Larry , Neller Todd , Petrov Plamen , Rovatsos Michael , Stork David G.
Published: October 2018

We are happy to present the annual activity report of ACM SIGAI, covering the period from July 2017 to June 2018.

The scope of ACM SIGAI consists of the study of intelligence and its realization in computer systems (see also our website at sigai.acm.org). This includes areas such as

autonomous agents, cognitive modeling, computer vision, constraint programming, human language technologies, intelligent user interfaces, knowledge discovery, knowledge representation and reasoning, machine learning, planning and search, problem solving, and robotics.

Our members come from academia, industry, and government agencies worldwide. We are thrilled to be able to report that our membership numbers increased by about 10 percent over the past year!

The terms of three of our officers (one of the two education activities officers, one of the two newsletter co-editors in chief, and the information officer) came to an end. We thank them for their valuable service and have now started to provide certificates of appreciation for outgoing officers. We appointed a new information officer and are currently looking for a new newsletter co-editor in chief and additional column editors. We also created and filled two new officer positions to be able to serve our members even better, namely an AI and society officer and a labor market officer.
AI profiles
Authors: Neumann Marion
Published: October 2018

This column is the sixth in our series profiling senior AI researchers. This month we interview Kristian Kersting, Professor in Computer Science and Deputy Director of the Centre for Cognitive Science at the Technical University of Darmstadt, Germany.
AI policy matters
Authors: Medsker Larry
Published: October 2018

AI Policy is a regular column in AI Matters featuring summaries and commentary based on postings that appear twice a month in the AI Matters blog (https://sigai.acm.org/aimatters/blog/). Selected posts are summarized in issues of
AI Matters.
Mechanism design for social good
Authors: Abebe Rediet , Goldner Kira
Published: October 2018

Across various domains---such as health, education, and housing---improving societal welfare involves allocating resources, setting policies, targeting interventions, and regulating activities. These solutions have an immense impact on the day-to-day lives of individuals, whether in the form of access to quality healthcare, labor market outcomes, or how votes are accounted for in a democratic society. Problems that can have an outsized impact on individuals whose opportunities have historically been limited often pose conceptual and technical challenges, requiring insights from many disciplines. Conversely, the lack of inter-disciplinary approach can leave these urgent needs unaddressed and can even exacerbate underlying socioeconomic inequalities.
The Bioarchaeology of Health Crisis: Infectious Disease in the Past
Authors: Larsen Clark Spencer
Published: October 2018

Beginning some 10,000 years ago, humans began a dramatic alteration in living conditions relating especially to the shift in lifeway from foraging to farming. In addition to the initiation of and increasing focus on the production and consumption of domesticated plant carbohydrates, this revolutionary transformation in diet occasioned a decline in mobility and an increased size and agglomeration of populations in semipermanent or permanent settlements. These changes in life conditions presented an opportunity for increased transmission of pathogenic microbes from host to host, such as those that cause major health threats affecting most of the 7.5 billion members of our species today. This article discusses the bioarchaeology of infectious disease, focusing on tuberculosis, treponematosis, dental caries, and periodontitis, all of which continue to contribute to high levels of morbidity and mortality among the world's populations today.
Interspecies Relations and Agrarian Worlds
Authors: Seshia Galvin Shaila
Published: October 2018

Recent years have witnessed burgeoning interest in interspecies relations and multispecies ethnography. This review explores what such perspectives bring to long-standing anthropological attention to agrarian worlds. Considering why so much recent scholarship only minimally engages with longer disciplinary traditions found within ecological and environmental anthropology and ethnobotany, the review examines continuities and discontinuities across these different modes of attending to interspecies relationships. From here, it explores how contemporary scholarship renews anthropological attention to questions of domestication, relatedness, agency, and personhood and how it charts new ground by engaging theories of biopolitics, biocapital, biosemiotics, and plant ontologies. While noting that recent work has distinctive theoretical preoccupations, the review concludes by suggesting that fruitful possibilities lie in working with, and across, established and emergent anthropologies of the agrarian.
Quantitative Controllability Index of Complex Networks
Authors: Wang Lifu , Zhang Yali , Han Jingxiao , Kong Zhi
Published: October 2018

In this paper, the controllability issue of complex network is discussed. A new quantitative index using knowledge of control centrality and condition number is constructed to measure the controllability of given networks. For complex networks with different controllable subspace dimensions, their controllability is mainly determined by the control centrality factor. For the complex networks that have the equal controllable subspace dimension, their different controllability is mostly determined by the condition number of subnetworks’ controllability matrix. Then the effect of this index is analyzed based on simulations on various types of network topologies, such as ER random network, WS small-world network, and BA scale-free network. The results show that the presented index could reflect the holistic controllability of complex networks. Such an endeavour could help us better understand the relationship between controllability and network topology.
Effect of Artificial Piglet Suckling Sounds on Behavior and Performance of Piglets and Adrenal Responses of Sows
Authors: Khonmee Jaruwan , Wathirunwong Thanat , Yano Terdsak , Somgird Chaleamchat , Brown Janine L. , Yamsakul Panuwat
Published: October 2018

Operation of the farrowing house is essential to the productivity of a swine farm, requiring not only good management but also knowledge of the behavior of sows and piglets. Stress can negatively affect production in farm animals and could be a factor in production indexes. The objective of this study was to investigate the effect of artificial sucking sounds on the behavior of piglets and fecal glucocorticoid (FGM) concentrations of sows. A total of 30 sows were divided into two groups: a treatment group (15 sows) was exposed to artificial sucking sounds and a control group (15 sows) was not. Both groups received the same management; the two open-house system locations were separated by a distance of about 270 meters. The study had three key objectives: to compare farrowing indexes and to observe the sucking behavior of piglets using CCTV cameras. Fecal samples were collected daily for 21 days from the period after parturition to weaning to assess adrenal activity. The treatment group had a significantly higher average number of times piglets came to a sow’s udder, and sows had a shorter onset time for the first piglet to come to the sow’s udder than the control group (bothP<0.05). The patterns and levels of FGM between the two groups were not different (bothP<0.05), but the treatment group had better farrowing indexes than the control group (P>0.05), particularly for litter weight gain and percent preweaning mortality. In addition, the weaning to first service interval of the treatment group was shorter than the control group (P<0.05). This indicates that the artificial suckling sound probably has no adverse effect on adrenal responses of pig; however, it improves production indexes of postparturition sows.
No Chattering and Adaptive Sliding Mode Control of a Fractional‐Order Phase Converter with Disturbances and Parameter Uncertainties
Authors: Rajagopal Karthikeyan , Weldegiorgis Riessom , Karthikeyan Anitha , Duraisamy Prakash , Tadesse Goitom
Published: October 2018

Discussing the dynamical properties of various power system models is of significant importance in order to understand its complete behavior. Even though there are many literatures discussing about the chaotic behavior shown by phase converter circuits, none of them have reported the hazardous phenomenon of multistability. In this paper, we derive the fractional‐order model of a phase converter circuit and investigate its dynamics. Bifurcation of the system with the parameters and fractional order are investigated. A forward and backward continuation scheme is adopted to display various coexisting attractors; the property of multistability is also discussed. Using forward and backward continuation, various coexisting attractors and the property of multistability are discussed. Two different sliding mode controllers for controlling chaotic oscillations with model disturbances and parameter uncertainties are derived, and the effectiveness of the controllers is discussed with numerical simulations.
Research on Speed Optimization Strategy of Hybrid Electric Vehicle Queue Based on Particle Swarm Optimization
Authors: Wang Shaohua , Yu Chengquan , Shi Dehua , Sun Xiaoqiang
Published: October 2018

Traffic lights intersections are common in cities and have an impact on the energy consumption of vehicles, so it is significant to optimize the velocities of vehicles in urban road conditions. The novel speed optimization strategy for hybrid electric vehicle (HEV) queue that helps reduce fuel consumption and improve traffic efficiency is presented in this paper, where real-world traffic signal information is used to construct the research scenario. The initial values of the target velocities are obtained based on the signal phase and timing (SPAT). Then the particle swarm optimization (PSO) algorithm is used to solve the nonlinear constrained problem and obtain the optimal target velocities based on vehicle to vehicle communication (V2V) and vehicle to infrastructure communication (V2I). The lower controller, which applies rule based control strategy, is designed to split the power of the engine and two electric motors in a power split HEV, which is quite promising because of its advantages in fuel economy. Simulation results demonstrate the superior performance of the proposed strategy in reducing fuel consumption of the HEV queue and improving traffic smoothness.
Finite‐Time Switching Control of Nonholonomic Mobile Robots for Moving Target Tracking Based on Polar Coordinates
Authors: Chen Hua , Xu Shen , Chu Lulu , Tong Fei , Chen Lei
Published: October 2018

In this paper, finite‐time tracking problem of nonholonomic mobile robots for a moving target is considered. First of all, polar coordinates are used to characterize the distance and azimuth between the moving target and the robot. Then, based on the distance and azimuth transported from the sensor installed on the robot, a finite‐time tracking control law is designed for the nonholonomic mobile robot by the switching control method. Rigorous proof shows that the tracking error converges to zero in a finite time. Numerical simulation demonstrates the effectiveness of the proposed control method.
Video Data Integrity Verification Method Based on Full Homomorphic Encryption in Cloud System
Authors: Liu Ruoshui , Liu Jianghui , Zhang Jingjie , Zhang Moli
Published: October 2018

Cloud computing is a new way of data storage, where users tend to upload video data to cloud servers without redundantly local copies. However, it keeps the data out of users' hands which would conventionally control and manage the data. Therefore, it becomes the key issue on how to ensure the integrity and reliability of the video data stored in the cloud for the provision of video streaming services to end users. This paper details the verification methods for the integrity of video data encrypted using the fully homomorphic crytosystems in the context of cloud computing. Specifically, we apply dynamic operation to video data stored in the cloud with the method of block tags, so that the integrity of the data can be successfully verified. The whole process is based on the analysis of present Remote Data Integrity Checking (RDIC) methods.
BTP: A Bedtime Predicting Algorithm via Smartphone Screen Status
Authors: Niu Kun , Zhang Shubo , Jiao Haizhen , Cheng Cheng , Wang Chao
Published: October 2018

For smartphone service providers, it is of vital importance to recognize characteristics of customers. The process of recognizing these characteristics is generally referred to as user profile, which provides knowledge basis for business decisions, enables intelligent services, and brings unique competitiveness. As a basic component of user profile, bedtime could reflect lifestyle, health condition, and occupation of people. This paper presents a flexible algorithm named BTP (Bedtime Prediction), which is designed for predicting wake time and bedtime by analysing screen status of smartphone. BTP first collects screen status log data of user’s smartphone and conducts preprocessing with a series of auxiliary user profiles. Then, it detects and records users’ wake time and bedtime of one day by searching and combining major screen extinguish periods in the past 24 hours. Finally, BTP predicts future bedtime by matching current screen status sequence with all historical records. By applying BTP, most of night and morning scenario‐based applications could provide more considerate services, rather than following fixed execution time like alarm clock. Experiments on practical applications prove that BTP can effectively predict wake time and bedtime without applying complicated machine learning algorithms or uploading data to server.
An Implementation Approach and Performance Analysis of Image Sensor Based Multilateral Indoor Localization and Navigation System
Authors: Shahjalal Md. , Hossan Md. Tanvir , Hasan Moh. Khalid , Chowdhury Mostafa Zaman , Le Nam Tuan , Jang Yeong Min
Published: October 2018

Optical camera communication (OCC) exhibits considerable importance nowadays in various indoor camera based services such as smart home and robot‐based automation. An android smart phone camera that is mounted on a mobile robot (MR) offers a uniform communication distance when the camera remains at the same level that can reduce the communication error rate. Indoor mobile robot navigation (MRN) is considered to be a promising OCC application in which the white light emitting diodes (LEDs) and an MR camera are used as transmitters and receiver, respectively. Positioning is a key issue in MRN systems in terms of accuracy, data rate, and distance. We propose an indoor navigation and positioning combined algorithm and further evaluate its performance. An android application is developed to support data acquisition from multiple simultaneous transmitter links. Experimentally, we received data from four links which are required to ensure a higher positioning accuracy.
Is Atorvastatin Associated with New Onset Diabetes or Deterioration of Glycemic Control? Systematic Review Using Data from 1.9 Million Patients
Authors: Angelidi Angeliki M. , Stambolliu Emelina , Adamopoulou Konstantina I. , Kousoulis Antonis A.
Published: October 2018

Background. Current evidence indicates that statins increase the risk of new onset diabetes mellitus (NOD) and also deteriorate the glycemic control in patients with known diabetes mellitus (DM) after high-dose statin therapy. Aims. The aim of this review was to explore the effect of atorvastatin in causing NOD or deteriorating glycemic control in patients with DM. Methods. Two independent reviewers conducted the literature search, through PubMed database searching for articles published in English until April 2015, and only primary studies were included. Results. Of the 919 articles identified in our original search, 33 met the criteria for this review encompassing 1,951,113 participants. Twenty articles examined dysregulation of DM due to atorvastatin. Half of them showed that there was no significant change in glycemic control in patients treated with atorvastatin. Other studies showed that fasting plasma glucose and HbA1c levels were increased by atorvastatin. Thirteen articles examined if atorvastatin causes NOD. The majority of these articles showed that patients who used atorvastatin had a higher dose-dependent risk of developing NOD. Conclusion. This systematic review suggests that there is an association between atorvastatin treatment and NOD. Moreover, it showed that atorvastatin in high dose causes worsening of the glycemic control in patients with DM.
An Efficient Method for Mining Erasable Itemsets Using Multicore Processor Platform
Authors: Huynh Bao , Vo Bay
Published: October 2018

Mining erasable itemset (EI) is an attracting field in frequent pattern mining, a wide tool used in decision support systems, which was proposed to analyze and resolve economic problem. Many approaches have been proposed recently, but the complexity of the problem is high which leads to time‐consuming and requires large system resources. Therefore, this study proposes an effective method for mining EIs based on multicore processors (pMEI) to improve the performance of system in aspect of execution time to achieve the better user experiences. This method also solves some limitations of parallel computing approaches in communication, data transfers, and synchronization. A dynamic mechanism is also used to resolve the load balancing issue among processors. We compared the execution time and memory usage of pMEI to other methods for mining EIs to prove the effectiveness of the proposed algorithm. The experiments show that pMEI is better than MEI in the execution time while the memory usage of both methods is the same.