bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling of Absolute Distance Meter Shift Inside a Laser Tracker
Authors: Li He , Landers Robert G. , Bristow Douglas A.
Published: July 2017

In the measurement of machine tool and robot geometric errors, one of the most extensively used instruments is the Laser Tracker (LT). Errors in the LT measurements will decrease the effectiveness of the error modeling and compensation methods that utilize these measurements. When the LT’s Absolute Distance Meter (ADM) is used without frequent referencing to a home position, large and long-term shifts occur. The ADM shift directly introduces errors in the radial component of every measurement in spherical coordinates, which will result in measurement errors in the Cartesian coordinates. Although the ADM shift is addressed in newer LT designs using internal referencing hardware, this paper presents a pragmatic and efficient software solution to ADM shift for LTs in which the internal referencing hardware is not embedded. The LT was measured for 22 hr in a temperature-constant room to examine the ADM shift effects on measurements. An ADM shift model was then proposed by assuming that the ADM shift equally affects radial components of all measurements wherever the target is, as long as it is within the measurement range. Another experiment was then performed to test the validity of the proposed model. After the model was identified and errors were corrected, the maximum temporal variation in the radial distance measurement is reduced by 80–86%.
Material Flow Analysis for the Incremental Sheet-Bulk Gearing by Rotating Tools
Authors: Wernicke Sebastian , Sieczkarek Peter , Grodotzki Joshua , Gies Soeren , Ben Khalifa Nooman , Tekkaya A. Erman
Published: July 2017

The manufacturing of gear elements by forming offers advantages regarding the resulting mechanical properties of the functional components. One possible approach is offered by the incremental sheet-bulk metal forming of gears using a linear motion punch. This method is highly flexible in terms of shape and position of the functional elements to be produced, but inefficient from an economical point of view due to the high process time. This paper presents a new sheet-bulk gear forming process using rotating tools in order to speed up the manufacturing process of load-adapted gears. Here, different concepts with rotating tools being synchronized and non-synchronized to the workpiece are investigated to form high-strength, load-adapted gears made of bainitic steel BS600. The focus is on the analysis of the occurring material flow which is examined by means of finite element analysis and microstructural investigations to ensure the manufacture of fully functional geared components by this sheet-bulk metal forming process.
Cutting Simulation in Drilling on Cylinder Surface in Turning Center Operation
Authors: Matsumura Takashi , Tamura Shoichi
Published: July 2017

Drillings and millings of cylinders are performed in operations on turning centers. Then, the drill holes are machined on the cylinder surfaces with offsets of the cutting positions from the workpiece axis. The paper presents an analytical model to predict the cutting force in drilling of cylinders. Three dimensional chip flow is interpreted as a piling of the orthogonal cuttings in the planes containing the cutting velocities and the chip flow velocities. In drilling, the chip flow models are made on the chisel and the lips. The chip flow directions are determined to minimize the cutting energies on the chisel and the lips. The workpiece model on the cylinder is defined by the cutting point with respect to the cylinder shape. The cutting force in drilling of a cylinder is compared with that in drilling of a plate. Then, the effect of the offset cutting points on the cutting force is discussed in terms of the resultant cutting force, which induces the machining error and the tool breakage.
Structure of Electrospray Printed Deposits for Short Spray Times
Authors: Brown Nicholas A. , Zhu Yaqun , Li Ao , Zhao Mingfei , Yong Xin , Chiarot Paul R.
Published: July 2017

In electrospray printing, a plume of highly charged droplets is created from a conductive ink. Printing occurs by positioning a target substrate in the path of the emitted material. Here, the ink used is a colloidal dispersion consisting of nanoparticles suspended in a volatile solvent. The selection of a volatile solvent allows for rapid evaporation of the droplets in-flight to produce dry nanoparticles. An excess electric charge is imparted on the emitted particles during electrospray. The interaction of this charge with the global electric field and with other charged particles/droplets governs the particles trajectory and determines the microstructure of the printed deposit. In this study, we characterized the structure of nanoparticle deposits printed using electrospray for short spray times. Electrospray printing is capable of exerting much finer control over microstructure compared to other printing techniques. This has significant implications for the manufacturing of thin-films.
FEM Investigation of the Effects of Impact Speed and Angle of Impacts of Abrasive in the Vibration Assisted Nano Impact Machining by Loose Abrasives
Authors: Duong Nick H. , Ma J. , Lei Shuting
Published: July 2017

In this paper, the commercial FEM software package Abaqus is employed to model the novel nanomachining process, Vibration Assisted Nano Impact machining by Loose Abrasives (VANILA), which combines the principles of vibration-assisted abrasive machining and tip-based nanomachining to conduct nano abrasive machining of hard and brittle materials. In this novel nanomachining process, an atomic force microscope (AFM) is used as a platform and the nano abrasives injected in slurry between the workpiece and the vibrating AFM probe impact the workpiece and result in nanoscale material removal. Diamond particles are used as the loose abrasives. The effects of impact speed, angle of impacts, and the frictional coefficient between the workpiece and abrasives are investigated using Abaqus. It is found that the impact speed, impact angle, and frictional coefficient between the silicon workpiece and nanoabrasives have big influence on the nanocavity’s size and depth.
Experimental Investigation of Key Process Parameters During Continuous-Bending-Under-Tension of AA6022-T4
Authors: Momanyi Edward M. , Roemer Timothy J. , Kinsey Brad L. , Korkolis Yannis P.
Published: July 2017

Continuous-Bending-Under-Tension (CBT) is an experimental technique that has been shown to increase elongation-to-fracture by over 100% in aluminum alloys and over 300% in steel as compared to uniaxial tensile tests [1]. This procedure is a modified form of a tensile test in which a specimen experiences 3 point plastic bending, induced by traversing 3 rollers back and forth over the gauge length, while simultaneously being pulled in tension. This process is able to delay the occurrence of necking in pure tension by suppressing the instability. Thus, significantly more elongation is achieved in the specimen prior to fracture. In this paper, an experimental investigation of key process parameters, i.e., bending depth and pulling speed, during CBT testing of AA6022-T4 is presented. The load cycle during a CBT test will also be discussed along with the strain induced throughout the gauge length.
Integrate Manufacturing Planning to Cloud Manufacturing Framework
Authors: Li Xiangyun , Zhang Luping , Yu Chunxia
Published: July 2017

We provide a cloud manufacturing based manufacturing planning framework for small and medium-sized enterprises. Manufacturing planning is conducted by separate units in the cloud instead of in corporations or manufacturing platforms. Disorders can be removed by the adoption of our newly-introduced units. To retain the workability of our new framework, three assumptions are imposed. A concrete case on process planning and scheduling is used for illustration of the necessity of our assumptions and operational mechanism of our design. Finally, a preliminary discuss on how intellect resources as well as small and medium-sized enterprises are involved to create a sustainable environment for small and medium-sized enterprises is placed.
Development of a New Laser-Assisted Additive Manufacturing Technology for Hybrid Functionally Graded Material Composites
Authors: Kim Jung Sub , Kim Young Chang , Lee Sang Won , Ko Jeonghan , Chung Haseung
Published: July 2017

This paper investigates a new technology to create functionally graded material (FGM) by additive manufacturing (AM). In particular, this paper focuses on creating graphene-polymer composite FGM by laser-based sintering processes. Graphene-polymer composites have received high attention in AM due to their excellent electrical conductivity, thermal stability and mechanical strength. However, AM of the graphene-polymer composites has a huge challenge to overcome. The heterogeneous materials should be mixed properly, and it is not easy to achieve the desired composite characteristics solely by changing the mass ratio of graphene. This paper shows a newly developed laser-assisted AM system for the graphene-polymer composite FGM by laser-based sintering processes. The paper also describes two methods of material integration: mixing graphene and polyethylene powders before sintering, and depositing the different material powders separately and sintering them. This study identified that the two methods led to different mechanical and electrical properties of the created parts. Thus this paper demonstrates the possibility to create quite useful hybrid (mechanically and electrically) FGM composites.
Study of Layer Formation During Droplet-Based 3D Printing of Gel Structures
Authors: Christensen Kyle , Huang Yong
Published: July 2017

Additive manufacturing, also known as three-dimensional (3D) printing, is an approach in which a structure may be fabricated layer by layer. For 3D inkjet printing, droplets are ejected from a nozzle and each layer is formed droplet by droplet. Inkjet printing has been widely applied for the fabrication of 3D biological gel structures, but the knowledge of the microscale interactions between printed droplets is still largely elusive. This study aims to elucidate the alginate layer formation process during drop-on-demand inkjet printing using high speed imaging and particle image velocimetry. Droplets are found to impact, spread, and coalesce within a fluid region at the deposition site, forming coherent printed lines within a layer. Interfaces are found to form between printed lines within a layer depending on printing conditions and printing path orientation. The effects of printing conditions on the behavior of droplets during layer formation are discussed and modeled based on gelation dynamics, and recommendations are presented to enable controllable and reliable fabrication of gel structures.
Study of Chip Morphology and Chip Formation Mechanism During Machining of Magnesium-Based Metal Matrix Composites
Authors: Davis Brian , Dabrow David , Ju Licheng , Li Anhai , Xu Chengying , Huang Yong
Published: July 2017

Magnesium (Mg) and its alloys are among the lightest metallic structural materials, making them very attractive for use in the aerospace and automotive industries. Recently, Mg has been used in metal matrix composites (MMCs), demonstrating significant improvements in mechanical performance. However, the machinability of Mg-based MMCs is still largely elusive. In this study, Mg-based MMCs are machined using a wide range of cutting speeds in order to elucidate both the chip morphology and chip formation mechanism. Cutting speed is found to have the most significant influence on both the chip morphology and chip formation mechanism, with the propensity of discontinuous, particle-type chip formation increasing as the cutting speed increases. Saw-tooth chips are found to be the primary chip morphology at low cutting speeds (lower than 0.5 m/s), while discontinuous, particle-type chips prevail at high cutting speeds (higher than 1.0 m/s). Using in situ high speed imaging, the formation of the saw-tooth chip morphology is found to be due to crack initiation at the free surface. However, as the cutting speed (and strain rate) increases, the formation of the discontinuous, particle-type chip morphology is found to be due to crack initiation at the tool tip. In addition, the influences of tool rake angle, particle size, and particle volume fracture are investigated and found to have little effect on the chip morphology and chip formation mechanism.
Graphene Growth on and Transfer From Platinum Thin Films
Authors: Cho Joon Hyong , Cullinan Michael
Published: July 2017

This paper presents graphene growth on Pt deposited on four different adhesion layers such as Ti, Cr, Ta, and Ni. During the graphene growth at 1000 °C using conventional Chemical Vapor Deposition method, these adhesion layers diffuse into and alloy with Pt layer resulting graphene to grow on different alloys. Therefore, Pt layer on different adhesion layers induces different quality and number of layer(s) of graphene grown on the film. Monolayer graphene was produced on majority of metal layers except on Pt/Ta layer where bilayer graphene is observed. The lowest defects were found on graphene grown on Pt/Ni film where slightly higher number of wrinkles are observed compared to other alloys. We characterized graphene using SEM images of transferred graphene, of Pt grains after the growth of graphene, and of in-depth profiles of thin film via TOF-SIMS. Our paper states feasibility of graphene growth on Pt thin film on various adhesion layers and obstacles to overcome to enhance graphene transfer from Pt thin film. We address one of the major difficulties of graphene growth and transfer to implement graphene in NEMS/MEMS devices.
Investigation on the Effects of Process Parameters on Defect Formation in Friction Stir Welded Samples via Predictive Numerical Modeling and Experiments
Authors: Ajri Abhishek , Shin Yung C.
Published: July 2017

Setting optimum process parameters is very critical in achieving a sound friction stir weld joint. Understanding the formation of defects and developing techniques to minimize them can help in improving the overall weld strength. The most common defects in friction stir welding are tunnel defects, cavities and excess flash formation which are caused due to incorrect tool rotational or advancing speed. In this paper, the formation of these defects is explained with the help of an experimentally verified 3D finite element model. It was observed that the asymmetricity in temperature distribution varies for different types of defects formed during friction stir welding. The location of the defect also changes based on the shoulder induced flow and pin induced flow during friction stir welding. Besides formation of defects like excess flash, cavity defects, tunnel/wormhole defects, two types of groove like defects are also discussed in this paper. By studying the different types of defects formed, a methodology is proposed to recognize these defects and counter them by modifying the process parameters to achieve a sound joint for a displacement based friction stir welding process.
Process and Operations Control in Modern Manufacturing
Authors: Djurdjanovic Dragan , Mears Laine , Akhavan Niaki Farbod , Ul Haq Asad , Li Lin
Published: July 2017

Dramatic advancements and adoption of computing capabilities, communication technologies, and advanced, pervasive sensing have impacted every aspect of modern manufacturing. Furthermore, as society explores the 4th Industrial Revolution characterized by access to and leveraging of knowledge in the manufacturing enterprise, the very character of manufacturing is rapidly evolving, with new, more complex processes and radically new products appearing in both the industries and academe. As for traditional manufacturing processes, they are also undergoing transformations in the sense that they face ever-increasing requirements in terms of quality, reliability and productivity, needs that are being addressed in the knowledge domain. Finally, across all manufacturing we see the need to understand and control interactions between various stages of any given process, as well as interactions between multiple products produced in a manufacturing system. All these factors have motivated tremendous advancements in methodologies and applications of control theory in all aspects of manufacturing: at process and equipment level, manufacturing systems level and operations level. Motivated by these factors, the purpose of this paper is to give a high-level overview of latest progress in process and operations control in modern manufacturing. Such a review of relevant work at various scales of manufacturing is aimed not only to offer interested readers information about state-of-the art in control methods and applications in manufacturing, but also to give researchers and practitioners a vision about where the direction of future research may be, especially in light of opportunities that lay as one concurrently looks at the process, system and operation levels of manufacturing.
Methylene blue improves mitochondrial respiration and decreases oxidative stress in a substrate-dependent manner in diabetic rat hearts
Authors: Duicu Oana M. , Privistirescu Andreea , Wolf Adrian , Petruş Alexandra , Dănilă Maria D. , Raţiu Corina D. , Muntean Danina M. , Sturza Adrian
Published: July 2017

Diabetic cardiomyopathy has been systematically associated with compromised mitochondrial energetics and increased generation of reactive oxygen species (ROS) that underlie its progression to heart failure. Methylene blue is a redox drug with reported protective effects mainly on brain mitochondria. The purpose of the present study was to characterize the effects of acute administration of methylene blue on mitochondrial respiration, H2O2production, and calcium sensitivity in rat heart mitochondria isolated from healthy and 2 months (streptozotocin-induced) diabetic rats. Mitochondrial respiratory function was assessed by high-resolution respirometry. H2O2production and calcium retention capacity were measured spectrofluorimetrically. The addition of methylene blue (0.1 μmol·L−1) elicited an increase in oxygen consumption of mitochondria energized with complex I and II substrates in both normal and diseased mitochondria. Interestingly, methylene blue elicited a significant increase in H2O2release in the presence of complex I substrates (glutamate and malate), but had an opposite effect in mitochondria energized with complex II substrate (succinate). No changes in the calcium retention capacity of healthy or diabetic mitochondria were found in the presence of methylene blue. In conclusion, in cardiac mitochondria isolated from diabetic and nondiabetic rat hearts, methylene blue improved respiratory function and elicited a dichotomic, substrate-dependent effect on ROS production.
Neuropeptide Y and its receptors in ventricular endocardial endothelial cells
Authors: Jacques Danielle , D’Orléans-Juste Pedro , Magder Sheldon , Bkaily Ghassan
Published: July 2017

Endocardial endothelial cells (EECs) constitute an important component of the heart. These cells form a monolayer that covers the cavities of the right (EECRs) and left (EECLs) ventricles. They play an important role in cardiac excitation–contraction coupling via their secretion of cardioactive factors such as neuropeptide Y (NPY). They also contribute to cardiac pathology such as arrhythmia, hypertrophy, and heart failure. Differences between EECRs and EECLs contribute to tuning of circulating factors at the entry and exit of the ventricles. NPY, via activation of its receptors, modulates the excitation–secretion coupling of EECs, thus, indirectly modulating cardiac function and remodeling.
A matrix method for quasinormal modes: Kerr and Kerr–Sen black holes
Authors: Lin Kai , Qian Wei-Liang , Pavan Alan B. , Abdalla Elcio
Published: July 2017

In this paper, a matrix method is employed to study the scalar quasinormal modes of Kerr as well as Kerr–Sen black holes. Discretization is applied to transfer the scalar perturbation equation into a matrix form eigenvalue problem, where the resulting radial and angular equations are derived by the method of separation of variables. The eigenvalues, quasinormal frequencies [Formula: see text] and angular quantum numbers [Formula: see text], are then obtained by numerically solving the resultant homogeneous matrix equation. This work shows that the present approach is an accurate, as well as efficient method for investigating quasinormal modes.
Analysis of the generalized (2+1)-dimensional Nizhnik–Novikov–Veselov equations with variable coefficients in an inhomogeneous medium
Authors: Chai Han-Peng , Tian Bo , Zhen Hui-Ling , Chai Jun , Guan Yue-Yang
Published: July 2017

Korteweg-de Vries (KdV)-type equations are seen to describe the shallow-water waves, lattice structures and ion-acoustic waves in plasmas. Hereby, we consider an extension of the KdV-type equations called the generalized (2[Formula: see text]+[Formula: see text]1)-dimensional Nizhnik–Novikov–Veselov equations with variable coefficients in an inhomogeneous medium. Via the Hirota bilinear method and symbolic computation, we derive the bilinear forms, N-soliton solutions and Bäcklund transformation. Effects of the first- and higher-order dispersion terms are investigated. Soliton evolution and interaction are graphically presented and analyzed: Both the propagation velocity and direction of the soliton change when the dispersion terms are time-dependent; The interactions between/among the solitons are elastic, independent of the forms of the coefficients in the equations.
Primordial nucleosynthesis
Authors: Coc Alain , Vangioni Elisabeth
Published: July 2017

Primordial nucleosynthesis, or big bang nucleosynthesis (BBN), is one of the three evidences for the big bang model, together with the expansion of the universe and the cosmic microwave background. There is a good global agreement over a range of nine orders of magnitude between abundances of4He, D,3He and7Li deduced from observations, and calculated in primordial nucleosynthesis. However, there remains a yet-unexplained discrepancy of a factor [Formula: see text], between the calculated and observed lithium primordial abundances, that has not been reduced, neither by recent nuclear physics experiments, nor by new observations. The precision in deuterium observations in cosmological clouds has recently improved dramatically, so that nuclear cross-sections involved in deuterium BBN needs to be known with similar precision. We will briefly discuss nuclear aspects related to the BBN of Li and D, BBN with nonstandard neutron sources, and finally, improved sensitivity studies using a Monte Carlo method that can be used in other sites of nucleosynthesis.
Limits on brane-world and particle dark radiation from big bang nucleosynthesis and the CMB
Authors: Sasankan N. , Gangopadhyay Mayukh R. , Mathews G. J. , Kusakabe M.
Published: July 2017

The term dark radiation is used both to describe a noninteracting neutrino species and as a correction to the Friedmann Equation in the simplest five-dimensional (5D) RS-II brane-world cosmology. In this paper, we consider the constraints on both the meanings of dark radiation-based upon the newest results for light-element nuclear reaction rates, observed light-element abundances and the power spectrum of the Cosmic Microwave Background (CMB). Adding dark radiation during big bang nucleosynthesis (BBN) alters the Friedmann expansion rate causing the nuclear reactions to freeze out at a different temperature. This changes the final light element abundances at the end of BBN. Its influence on the CMB is to change the effective expansion rate at the surface of the last scattering. We find that the BBN constraint reduces the allowed range for both types of dark radiation at 10[Formula: see text]Mev to between [Formula: see text] and [Formula: see text] of the total background energy density at 10[Formula: see text]Mev. Combining this result with fits to the CMB power spectrum, produces different results for particle versus brane-world dark radiation. In the brane-world, the range decreases from [Formula: see text] to [Formula: see text]. Thus, we find that the ratio of dark radiation to the background total relativistic mass energy density [Formula: see text] is consistent with zero although there remains a very slight preference for a positive (rather than negative) contribution.
Competition Trading and Exporting Acting by Inter Marketing Managers
Authors: Farahmand Nasser Fegh-Hi
Published: July 2017

In order to achieve marketing success, it is important to understand the relationship between marketing strategy planning by marketing managers and strategy deployment success. Trading and Exporting Organisations (TEOs) influence whether or not those organisations engage in Competition Trading and Exporting Acting (CTEA). The focus is primarily on the environmental characteristics of Inter marketing Managers (IMs) such as education and prior experience rather than those characteristics derived from personality traits. Data are drawn from a survey of the TEO in trading and industrial zones of North West of Iran that around one-sixth the samples of IM engage in CTEA. The IM characteristics showing a significant association with a commitment to CTEA include an above average level of education, experience and running organisation in sectors outside their previous experience. CTEA showed a positive association with those IM with a growth orientation. It is concluded that IM characteristics can be important in explaining the CTEA within the TEO.
Small-data computing
Authors: Boehm Hans-J.
Published: July 2017

Rounding errors are usually avoidable, and sometimes we can afford to avoid them.
Now that we can write
simultaneously
, how do we use that to our advantage?
Authors: Olenewa Ricardo , Olson Gary M. , Olson Judith S. , Russell Daniel M.
Published: July 2017

Word processors now make it possible for many authors to work on the same document concurrently. But what can they actually do?
Remote Sighted Assistants for Indoor Location Sensing of Visually Impaired Pedestrians
Authors: Rafian Paymon , Legge Gordon E.
Published: July 2017

Because indoor navigation is difficult for people with visual impairment, there is a need for the development of assistive technology. Indoor location sensing, the ability to identify a pedestrian's location and orientation, is a key component of such technology. We tested the accuracy of a potential crowdsourcing-based indoor location sensing method. Normally sighted subjects were asked to identify the location and facing direction of photos taken by a pedestrian in a building. The subjects had available a floor plan and a small number of representative photos from key locations within the floor plan. Subjects were able to provide accurate location estimates (median location accuracy 3.87ft). This finding indicates that normally sighted subjects, with minimal training, using a simple graphical representation of a floor plan, can provide accurate location estimates based on a single, suitable photo taken by a pedestrian. We conclude that indoor localization is possible using remote, crowdsourced, human assistance. This method has the potential to be used for the location-sensing component of an indoor navigation aid for people with visual impairment.
On Orienting Edges of Unstructured Two- and Three-Dimensional Meshes
Authors: Agelek Rainer , Anderson Michael , Bangerth Wolfgang , Barth William L.
Published: July 2017

Finite element codes typically use data structures that represent unstructured meshes as collections of cells, faces, and edges, each of which require associated coordinate systems. One then needs to store how the coordinate system of each edge relates to that of neighboring cells. However, we can simplify data structures and algorithms if we can a priori orient coordinate systems in such a way that the coordinate systems on the edges follow uniquely from those on the cells by rule.

Such rules require that every unstructured mesh allow the assignment of directions to edges that satisfy the convention in adjacent cells. We show that the convention chosen for unstructured quadrilateral meshes in the
deal.II
library always allows to orient meshes. It can therefore be used to make codes simpler, faster, and less bug prone. We present an algorithm that orients meshes in
O
(
N
) operations. We then show that consistent orientations are not always possible for 3D hexahedral meshes. Thus, cells generally need to store the direction of adjacent edges, but our approach also allows the characterization of cases where this is not necessary. The 3D extension of our algorithm either orients edges consistently, or aborts, both within
O
(
N
) steps.
Social Incentives in Paid Collaborative Crowdsourcing
Authors: Feyisetan Oluwaseyi , Simperl Elena
Published: July 2017

Paid microtask crowdsourcing has traditionally been approached as an individual activity, with units of work created and completed independently by the members of the crowd. Other forms of crowdsourcing have, however, embraced more varied models, which allow for a greater level of participant interaction and collaboration. This article studies the feasibility and uptake of such an approach in the context of paid microtasks. Specifically, we compare engagement, task output, and task accuracy in a paired-worker model with the traditional, single-worker version. Our experiments indicate that collaboration leads to better accuracy and more output, which, in turn, translates into lower costs. We then explore the role of the social flow and social pressure generated by collaborating partners as sources of incentives for improved performance. We utilise a Bayesian method in conjunction with interface interaction behaviours to detect when one of the workers in a pair tries to exit the task. Upon this realisation, the other worker is presented with the opportunity to contact the exiting partner to stay: either for personal financial reasons (i.e., they have not completed enough tasks to qualify for a payment) or for fun (i.e., they are enjoying the task). The findings reveal that: (1) these socially motivated incentives can act as furtherance mechanisms to help workers attain and exceed their task requirements and produce better results than baseline collaborations; (2) microtask crowd workers are empathic (as opposed to selfish) agents, willing to go the extra mile to help their partners get paid; and, (3) social furtherance incentives create a win-win scenario for the requester and for the workers by helping more workers get paid by re-engaging them before they drop out.
Collusive Opinion Fraud Detection in Online Reviews
Authors: Xu Chang , Zhang Jie
Published: July 2017

We address the collusive opinion fraud problem in online review portals, where groups of people work together to deliver deceptive reviews for manipulating the reputations of targeted items. Such collusive fraud is considered much harder to defend against, since the participants (or colluders) can evade detection by shaping their behaviors collectively so as not to appear suspicious. To alleviate this problem, countermeasures have been proposed that leverage the collective behaviors of colluders. The motivation stems from the observation that colluders typically act in a very synchronized way, as they are instructed by the same campaigns with common items to target and schedules to follow. However, the collective behaviors examined in existing solutions focus mostly on the external appearance of fraud campaigns, such as the campaign size and the size of the targeted item set. These signals may become ineffective once colluders have changed their behaviors collectively. Moreover, the detection algorithms used in existing approaches are designed to only make collusion inference on the input data; predictive models that can be deployed for detecting emerging fraud cannot be learned from the data. In this article, to complement existing studies on collusive opinion fraud characterization and detection, we explore more subtle behavioral trails in collusive fraud practice. In particular, a suite of homogeneity-based measures are proposed to capture the interrelationships among colluders within campaigns. Moreover, a novel statistical model is proposed to further characterize, recognize, and predict collusive fraud in online reviews. The proposed model is fully unsupervised and highly flexible to incorporate effective measures available for better modeling and prediction. Through experiments on two real-world datasets, we show that our method outperforms the state of the art in both characterization and detection abilities.
The science of brute force
Authors: Heule Marijn J. H. , Kullmann Oliver
Published: July 2017

Mathematics solves problems by pen and paper. CS helps us to go far beyond that.
Is the U.S. education system ready for CS for all?
Authors: Wang Jennifer
Published: July 2017

Insights from a recent Google-Gallup national research study seeking to better understand the context of K--12 CS education.
Review of 3D Printed Millimeter-Wave and Terahertz Passive Devices
Authors: Zhang Bing , Chen Wei , Wu Yanjie , Ding Kang , Li Rongqiang
Published: July 2017

The 3D printing technology is catching attention nowadays. It has certain advantages over the traditional fabrication processes. We give a chronical review of the 3D printing technology from the time it was invented. This technology has also been used to fabricate millimeter-wave (mmWave) and terahertz (THz) passive devices. Though promising results have been demonstrated, the challenge lies in the fabrication tolerance improvement such as dimensional tolerance and surface roughness. We propose the design methodology of high order device to circumvent the dimensional tolerance and suggest specific modelling of the surface roughness of 3D printed devices. It is believed that, with the improvement of the 3D printing technology and related subjects in material science and mechanical engineering, the 3D printing technology will become mainstream for mmWave and THz passive device fabrication.
Are All Mutations the Same? A Rare Case Report of Coexisting Mutually Exclusive KRAS and BRAF Mutations in a Patient with Metastatic Colon Adenocarcinoma
Authors: Vittal Anusha , Middinti Akshay , Kasi Loknath Kumar Anup
Published: July 2017

29-year-old Hispanic woman presented to the clinic with complaints of abdominal pain, nausea, fatigue, and constipation. Laboratory tests indicated the presence of iron deficiency anemia and transaminitis. Imaging evaluation revealed marked hepatomegaly with multiple hepatic metastases and pelvic lymphadenopathy. Biopsy of the hepatic lesions showed adenocarcinoma positive for pan-cytokeratin, CMA5.2, villin, and CDX2. She was positive for tumor markers CA 19-9, CA-125, and CEA. Upon further evaluation, she was found to have colorectal cancer positive for KRAS and BRAF mutations. Unfortunately, her disease progressed rapidly and she expired within 3 months from the time of her first diagnosis. KRAS and BRAF mutations are rare enough to be considered virtually mutually exclusive but coexistent mutations appear to be a distinct molecular and clinical subset with aggressive course of illness, which is in dire need of new treatment strategies. Panitumumab and Cetuximab are approved for patients with wild type KRAS CRC. Vemurafenib is a potent inhibitor of the kinase domain in mutant BRAF and its use in BRAF mutated colon cancer remains to be well established. Our report highlights the need to obtain tissue samples from these patients for analysis and to evaluate the benefit of Vemurafenib in colorectal cancers.
Evaluation of Adrenal Function in Nonhospitalized Patients with Cirrhosis
Authors: Moini Maryam , Yazdani Sarvestani Mitra , Shams Mesbah , Nomovi Masood
Published: July 2017

Background. Patients with cirrhosis and advancing hepatic insufficiency may show various degrees of other organ malfunction, including brain, kidney, and lung. Several studies have also shown a high prevalence of adrenal insufficiency in cirrhotic patients that may cause hemodynamic instability. Materials and Methods. In this study we prospectively evaluated adrenal function in a population of nonhospitalized cirrhotic patients. Categorization of liver disease severity was done according to model for end-stage liver disease (MELD) score. Adrenocorticotropic hormone stimulation testing was performed on subjects using 250 μg of synthetic short acting hormone; radio immunoassay was used to measure plasma cortisol levels. Results. Of 105 cirrhotic patients, 15.23% had evidence of adrenal insufficiency. These patients were not statistically different from those with normal adrenal function in levels of serum creatinine or bilirubin, MELD score, or presence of cirrhosis related complications. Significant differences were seen in mean international normalized ratio and serum sodium. Patients with a sodium level < 135 mEq/L had a higher rate (31.25%) of adrenal insufficiency. Conclusion. Adrenal dysfunction was identified in a population of stable nonhospitalized cirrhotic patients. Our results suggest a possible role for adrenal dysfunction as a contributing factor in hyponatremia in cirrhosis independent of other known factors of neurohormonal activation secondary to systemic vasodilation.
Autoscopic Hallucination in Alcohol Dependence Syndrome: A Rare or Missed Phenomenon?
Authors: Joshi Sulochana , Thapa Binita , Shakya Rabi
Published: July 2017

Autoscopic phenomenon, a psychic illusionary duplication of one’s own self, has been the subject of interest in the literature and science for years. It has been reported in various diseases of the central nervous system but with an unknown mechanism. Hallucinations are a common presentation in alcohol dependence syndrome during delirium tremens and as induced disorder. However, autoscopic hallucination has been rarely reported in the cases of alcohol dependence. We present a case of a 40-year-old man who experienced autoscopic hallucination during the withdrawal state of alcohol. He was successfully treated with detoxification and an antipsychotic medication and was doing well. The case highlights the need for strong suspicion and exploration of the autoscopic hallucination and autoscopic phenomenon in general in cases of alcohol dependence syndrome.
The Estimates of Retinal Ganglion Cell Counts Performed Better than Isolated Structure and Functional Tests for Glaucoma Diagnosis
Authors: Esporcatte Bruno L. B. , Kara-José Andrea C. , Melo Luiz Alberto S. , Pinto Luciano M. , Tavares Ivan M.
Published: July 2017

Purpose. To evaluate the diagnostic accuracy of retinal ganglion cell (RGC) counts as estimated by combining data from standard automated perimetry (SAP) and spectral domain optical coherence tomography (SD-OCT).Methods. Healthy individuals and glaucoma patients were included in this cross-sectional study. All eyes underwent 24-2 SITA SAP and structural imaging tests. RGC count estimates were obtained using a previously described algorithm, which combines estimates of RGC numbers from SAP sensitivity thresholds and SD-OCT retinal nerve fiber layer (RNFL) average thickness.Results. A total of 119 eyes were evaluated, including 75 eyes of 48 healthy individuals and 44 eyes of 29 glaucoma patients. RGC count estimates performed better than data derived from SD-OCT RNFL average thickness or SAP mean deviation alone (area under ROC curves: 0.98, 0.92, and 0.79;P<0.001) for discriminating healthy from glaucomatous eyes, even in a subgroup of eyes with mild disease (0.97, 0.88, and 0.75;P<0.001). There was a strong and significant correlation between estimates of RGC numbers derived from SAP and SD-OCT (R2=0.74;P<0.001).Conclusion. RGC count estimates obtained by combined structural and functional data showed excellent diagnostic accuracy for discriminating the healthy from the glaucomatous eyes and performed better than isolated structural and functional parameters.
ABO Gene Polymorphism and Thrombomodulin −33G>A Polymorphism Were Not Risk Factors for Myocardial Infarction in Javanese Men
Authors: Lukitasari Mifetika , Sadewa Ahmad Hamim , Rohman Mohammad Saifur
Published: July 2017

Genetic factors contribute to about a half of coronary artery diseases. During the last several decades, some studies suggested that non-O blood group and thrombomodulin polymorphism −33G>A are the risk factors of coronary artery disease especially in Asia. There was no prior study in Indonesia regarding this issue. Hence, this study was designed to investigate the correlation of ABO polymorphism and thrombomodulin polymorphism −33G>A with the incidence of acute myocardial infarction (AMI). A total of 192 subjects were enrolled in this case control study. AMI patients were diagnosed based on World Health Organization criteria. Healthy patients were subjects with AMI risk factor without any sign and symptoms of AMI. Patients with diabetes mellitus, cancer, and arrhythmia were excluded from this study. Genotyping for both polymorphisms was performed by PCR RFLP methods. The result of this study suggested that ABO polymorphism and thrombomodulin polymorphism −33G>A were not risk factors of AMI,p=0.727andp=0.699, respectively. Furthermore, the analysis to identify the synergy of these polymorphisms failed to prove their correlation with AMI(p=0.118). Conclusively, this study showed that ABO polymorphism and thrombomodulin polymorphism −33G>A were not risk factors of AMI.
Pars Plana Vitrectomy with Internal Limiting Membrane Peeling in Traumatic Macular Hole: 14% Perfluoropropane (C3F8) versus Silicone Oil Tamponade
Authors: Bor’i Ashraf , Al-Aswad Mahmoud A. , Saad Ahmed Abdelwahab , Hamada Dina , Mahrous Ashraf
Published: July 2017

Purpose. To evaluate the outcome of 23 G PPV and ILM peeling with 14% C3F8 compared with silicone oil tamponade in cases of TMHs without spontaneous closure. Methods. A retrospective comparative study included 33 eyes with TMHs; 7 eyes healed spontaneously, and the remaining 26 eyes have been treated with PPV and ILM peeling. Silicone oil was used as a tamponade for children or adults who refused to adopt face-down position (10 cases). In all other cases (16 cases), 14% C3F8 was used. These cases were followed up for 6 months postoperatively. Results. 26 cases (22 males and 4 females) were reviewed, including 10 cases treated with silicone oil and 16 cases treated with 14% C3F8. Patients’ age ranged from 9 to 54 years. The success rate was 90% in the silicone-filled (9/10) and 94% in the gas-filled (15/16) eyes. At 6 months, the mean BCVA was 0.3 ± 0.25 in the silicone group and 0.2 ± 0.13 in the gas group (p<0.05). Conclusions. Cases of TMHs should be observed for spontaneous closure. PPV with ILM peeling should be conducted for nonclosing cases. Gas and silicone oil tamponades are equally successful in anatomical and visual outcomes. This trial is registered with CTRI/2017/06/008765.
Novel Thiazole Derivatives of Medicinal Potential: Synthesis and Modeling
Authors: Abdel-Sattar Nour E. A. , El-Naggar Abeer M. , Abdel-Mottaleb M. S. A.
Published: July 2017

This paper reports on the synthesis of new thiazole derivatives that could be profitably exploited in medical treatment of tumors. Molecular electronic structures have been modeled within density function theory (DFT) framework. Reactivity indices obtained from the frontier orbital energies as well as electrostatic potential energy maps are discussed and correlated with the molecular structure. X-ray crystallographic data of one of the new compounds is measured and used to support and verify the theoretical results.
Surgical Approach May Influence Survival of Large-Diameter Head Metal-on-Metal Total Hip Arthroplasty: A 6- to 10-Year Follow-Up Study
Authors: Hu Chih-Chien , Huang Tsan-Wen , Lin Shih-Jie , Lin Po-Chun , Kuo Feng-Chih , Peng Kuo-Ti , Huang Kuo-Chin , Shih Hsin-Nung , Lee Mel S.
Published: July 2017

Large-diameter head (LDH) metal-on-metal (MoM) total hip arthroplasty (THA) has lost popularity because of metal allergy or ALTRs (adverse local tissue reactions) in the past decade. Whether the surgical approach may influence the survival of LDH-MoM-THA has not been reported. From 2006 to 2009, we performed 96 LDH-MoM-THAs on 80 patients using an in situ head-neck assembly technique through a modified Watson-Jones approach. With a mean follow-up of 8.4 years (range, 6.3–10.1 years), the implant survival rate was 100%. All patients were satisfied with the results and the Harris Hip Score improved from 52 points to 98 points. No ALTRs were found, but 17.7% of the 96 hips (17 adverse events) experienced adverse events related to the cup, including 5 cases of outlier cup malposition, 11 cases of inadequate cup seating, and 1 acetabular fracture. The tissue tension that was improved by a muscle-sparing approach might lessen the chance of microseparation or edge-loading that is taken as the major risk for early implant failure. Further investigation of whether these LDH-MoM-THAs would fail or not would require a longer follow-up or even retrieval analysis in the future.
MRI Texture Analysis of Background Parenchymal Enhancement of the Breast
Authors: Amano Yasuo , Woo Jun , Amano Maki , Yanagisawa Fumi , Yamamoto Hiroshi , Tani Mayumi
Published: July 2017

Purpose.The purpose of this study was to determine texture parameters reflecting the background parenchymal enhancement (BPE) of the breast, which were acquired using texture analysis (TA).Methods.We investigated 52 breasts of the 26 subjects who underwent dynamic contrast-enhanced MRI. One experienced reader scored BPE visually (i.e., minimal, mild, moderate, and marked). TA, including 12 texture parameters, was performed to distinguish the BPE scores quantitatively. Relationships between the visual BPE scores and texture parameters were evaluated using analysis of variance and receiver operating characteristic analysis.Results.The variance and skewness of signal intensity were useful for differentiating between moderate and mild or minimal BPE or between mild and minimal BPE, respectively, with the cutoff value of 356.7 for variance and that of 0.21 for skewness. Some TA features could be useful for defining breast lesions from the BPE.Conclusion.TA may be useful for quantifying the BPE of the breast.
Effect of Solidification Rate and Rare Earth Metal Addition on the Microstructural Characteristics and Porosity Formation in A356 Alloy
Authors: Mahmoud M. G. , Samuel A. M. , Doty H. W. , Valtierra S. , Samuel F. H.
Published: July 2017

The present study was performed on A356 alloy with the main aim of investigating the effects of La and Ce additions to 356 alloys (with and without 100 ppm Sr) on the microstructure and porosity formation in these alloys. Measured amounts of La, Ce, and Sr were added to the molten alloy. The results showed that, in the absence of Sr, addition of La and Ce leads to an increase in the nucleation temperature of the α-Al dendritic network with a decrease in the temperature of the eutectic Si precipitation, resulting in increasing the freezing range. Addition of 100 ppm Sr results in neutralizing these effects. The presence of La or Ce in the casting has a minor effect on eutectic Si modification, in spite of the observed depression in the eutectic temperature. It should be noted that Ce is more effective than La as an alternate modifying agent. According to the atomic radius ratio, rLa/rSi is 1.604 and rCe/rSi is 1.559, theoretically, which shows that Ce is relatively more effective than La. The present findings confirm that Sr is the most dominating modification agent. Interaction between rare earth (RE) metals and Sr would reduce the effectiveness of Sr. Although modification with Sr causes the formation of shrinkage porosity, it also reacts with RE-rich intermetallics, resulting in their fragmentation.