bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of the Gas Filling and Evacuation Processes in an Inertial Confinement Fusion (ICF) Hohlraum
Authors: Wu Liangyu , Zhou Hua , Yu Cheng , Yao Feng
Published: May 2019

In indirect inertial confinement fusion (ICF), the prediction of gas pressures and mass flow rates in the hohlraum is critical for fielding the hohlraum film and the support tent. To this end, it is desirable to understand the gas filling and evacuation process through the microcapillary fill tube and the support tent. In this work, a unified flow simulation of the filling and evacuation processes through the microcapillary fill tube and the support tent in an ICF hohlraum was conducted to study the gas pressure and mass flow rate in the hohlraum. The effects of the support tent size and the microcapillary fill tube size on the critical pressure variation and pressure difference across the hole on the support tent are examined. The results indicate that an increase in the diameter of the hole and the hole number leads to a smaller pressure difference across the hole on the support tent. If the diameter of the hole on the support tent is larger than 0.06 mm, the critical pressure variation rate is nearly independent of the diameter and the hole number. Increases in the diameter and decreases in the length of the microcapillary fill tube induce a larger critical pressure variation rate and pressure difference across the hole, which is conductive to fielding the hohlraum film.
Scientific Production and Productivity for Characterizing an Author’s Publication History: Simple and Nested Gini’s and Hirsch’s Indexes Combined
Authors: Zagonari Fabio
Published: May 2019

In this study, I developed operational versions of Gini’s and Hirsch’s indexes that can be applied to characterize each researcher’s publication history (PH) as heterodox, orthodox, and interdisciplinary. In addition, the new indicators warn against anomalies that potentially arise from tactical or opportunistic citation and publication behaviors by authors and editors, and can be calculated from readily available information. I split the original Hirsch index into nested indexes to isolate networking activity, as well as to distinguish scientific production (number of articles) from scientific productivity (rate of production), and used nested Gini indexes to identify intentional and successful intertopical and interdisciplinary research. I applied the most popular standardizations (i.e., per author and per year), and used simple methodologies (i.e., least-squares linear and cubic fitting, whole-career vs. subperiods, two-dimensional graphs). I provide three representative numerical examples based on an orthodox multidisciplinary PH, a heterodox PH from the social sciences, and an orthodox unidisciplinary PH from the physical sciences. Two additional numerical examples based on PHs from the life and health sciences show that the suggested PH characterization can be applied to different disciplines where different publication and citation practices prevail. Software is provided to help readers explore the use of these indicators.
The Relationship of Vulnerability to Religiosity in the Adult Jewish Learner
Authors: Brown Erica
Published: May 2019

This article examines the role of vulnerability in personal religious transformation. It offers several “working” definitions of the terms and also mines the use of the term through the portrait of three adult Jewish learners who each experienced vulnerability as a result of Jewish text study for different reasons. This sense of vulnerability was either itself a religious experience characterized as a mixture of humility, gratitude, and belonging or catalyzed enhanced study that led to a greater sense of knowledge of and participation within a religious community. Vulnerability is understood by one learner as the insecurity of ignorance, which inspired her to take agency for her learning and compensate for pre-existing gaps. For the second, vulnerability is less about ignorance or openness in an act of study, but the insecurity of the performative aspects of Judaism in the shared space of community. This prompted him to learn more to overcome these uncomfortable feelings. For another, vulnerability represents an existential state of humanity that connects all people. Vulnerability for her is a positive state of openness; she seeks out Jewish experiences of study and prayer where she can exhibit her vulnerability in the presence of others equally willing to share their own moments of joy, doubt, humility, and failure. In each instance, vulnerability created a paradoxical motivation to study—the discomfort of not fitting in or knowing enough that, in turn, gave rise to feelings of enhanced religiosity induced by the study experience. To that end, the paper also explores vulnerability as a generative aspect of transformative learning that leads to enhanced spiritual states.
Resource Allocation in Oil-Dependent Communities: Oil Rent and Benefit Sharing Arrangements
Authors: Tulaeva Svetlana , Nysten-Haarala Soili
Published: May 2019

This study is dedicated to the interaction between oil and gas companies and local communities that depend deeply on the production of oil. One of the key concerns of all oil-dependent communities is the distribution of oil rent: Who participates in decision making regarding the distribution of oil profits and who can claim the benefits and on what grounds? Benefit sharing arrangements are used to decide such matters in global practice. Using Russian Arctic and subarctic areas as examples, we analyze the main rules and practices of the distribution of benefits from oil production at the local level. This study focuses on the coexistence of oil companies and indigenous people, many of whom practice a traditional way of life. We also pay attention to the institutionalization of the norms and rules of oil-dependent communities at the local level.
Direct and Hierarchical Models for Aggregating Spatially Dependent Catastrophe Risks
Authors: Wójcik Rafał , Liu Charlie Wusuo , Guin Jayanta
Published: May 2019

We present several fast algorithms for computing the distribution of a sum of spatially dependent, discrete random variables to aggregate catastrophe risk. The algorithms are based on direct and hierarchical copula trees. Computing speed comes from the fact that loss aggregation at branching nodes is based on combination of fast approximation to brute-force convolution, arithmetization (regriding) and linear complexity of the method for computing the distribution of comonotonic sum of risks. We discuss the impact of tree topology on the second-order moments and tail statistics of the resulting distribution of the total risk. We test the performance of the presented models by accumulating ground-up loss for 29,000 risks affected by hurricane peril.
A New Single-Pass SAR Interferometry Technique with a Single-Antenna for Terrain Height Measurements
Authors: Ka Min-Ho , Shimkin Pavel E. , Baskakov Aleksandr I. , Babokin Mikhail I.
Published: May 2019

One of the prospective research topics in radar remote sensing technology is the methodology for designing an optimal radar system for high-precision two-dimensional and three-dimensional image acquisition of the Earth’s surface with minimal hardware requirements. In this study, we propose a single-pass interferometric synthetic aperture radar (SAR) imaging technique with only a single antenna for the estimation of the terrain height. This technique enabled us to obtain terrain height information in one flight of the carrier, on which only one receiving antenna was mounted. This single-antenna single-pass interferometry required a squint angle look geometry and additional image synthesis processing. The limiting accuracy of the terrain height measurement was approximately 1.5 times lower than that of the conventional two-pass mode and required a longer baseline than two-pass interferometry to have an equivalent accuracy performance. This imaging method could overcome the temporal decorrelation problem of two-pass interferometry due to a short time gap in the radar echo acquisitions during two sub-aperture intervals. We compared the accuracy performance of the terrain height measurements of our method with the conventional two-pass interferometry. This comparison was carried out at various spectral bandwidths, degrees of surface roughness, and baseline lengths. We validated our idea with numerical simulations of a digital elevation map, and showed real extracted data of the terrain heights in the Astrakhan and Volga regions of the Russian Federation, obtained from airborne SAR with our single-antenna single-pass interferometry technique.
Proximity Gettering Design of Hydrocarbon–Molecular–Ion–Implanted Silicon Wafers Using Dark Current Spectroscopy for CMOS Image Sensors
Authors: Kurita Kazunari , Kadono Takeshi , Shigematsu Satoshi , Hirose Ryo , Okuyama Ryosuke , Onaka-Masada Ayumi , Okuda Hidehiko , Koga Yoshihiro
Published: May 2019

We developed silicon epitaxial wafers with high gettering capability by using hydrocarbon–molecular–ion implantation. These wafers also have the effect of hydrogen passivation on process-induced defects and a barrier to out-diffusion of oxygen of the Czochralski silicon (CZ) substrate bulk during Complementary metal-oxide-semiconductor (CMOS) device fabrication processes. We evaluated the electrical device performance of CMOS image sensor fabricated on this type of wafer by using dark current spectroscopy. We found fewer white spot defects compared with those of intrinsic gettering (IG) silicon wafers. We believe that these hydrocarbon–molecular–ion–implanted silicon epitaxial wafers will improve the device performance of CMOS image sensors.
A Spray-on, Nanocomposite-Based Sensor Network for in-Situ Active Structural Health Monitoring
Authors: Cao Wuxiong , Zhou Pengyu , Liao Yaozhong , Yang Xiongbin , Pan Dongyue , Li Yehai , Pang Baojun , Zhou Li-min , Su Zhongqing
Published: May 2019

A new breed of nanocomposite-based spray-on sensor is developed for in-situ active structural health monitoring (SHM). The novel nanocomposite sensor is rigorously designed with graphene as the nanofiller and polyvinylpyrrolidone (PVP) as the matrix, fabricated using a simple spray deposition process. Electrical analysis, as well as morphological characterization of the spray-on sensor, was conducted to investigate percolation characteristic, in which the optimal threshold (~0.91%) of the graphene/PVP sensor was determined. Owing to the uniform and stable conductive network formed by well-dispersed graphene nanosheets in the PVP matrix, the tailor-made spray-on sensor exhibited excellent piezoresistive performance. By virtue of the tunneling effect of the conductive network, the sensor was proven to be capable of perceiving signals of guided ultrasonic waves (GUWs) with ultrahigh frequency up to 500 kHz. Lightweight and flexible, the spray-on nanocomposite sensor demonstrated superior sensitivity, high fidelity, and high signal-to-noise ratio under dynamic strain with ultralow magnitude (of the order of micro-strain) that is comparable with commercial lead zirconate titanate (PZT) wafers. The sensors were further networked to perform damage characterization, and the results indicate significant application potential of the spray-on nanocomposite-based sensor for in-situ active GUW-based SHM.
Animations in Cross-Platform Mobile Applications: An Evaluation of Tools, Metrics and Performance
Authors: Biørn-Hansen Andreas , Grønli Tor-Morten , Ghinea Gheorghita
Published: May 2019

Along with the proliferation of high-end and performant mobile devices, we find that the inclusion of visually animated user interfaces are commonplace, but that research on their performance is scarce. Thus, for this study, eight mobile apps have been developed for scrutiny and assessment to report on the device hardware impact and penalties caused by transitions and animations, with an emphasis on apps generated using cross-platform development frameworks. The tasks we employ for animation performance measuring, are those of (i) a complex animation consisting of multiple elements, (ii) the opening sequence of a side menu navigation pattern, and (iii) a transition animation during in-app page navigation. We employ multiple performance profiling tools, and scrutinize metrics including frames per second (FPS), CPU usage, device memory usage and GPU memory usage, all to uncover the impact caused by executing transitions and animations. We uncover important differences in device hardware utilization during animations across the different cross-platform technologies employed. Additionally, Android and iOS are found to differ greatly in terms of memory consumption, CPU usage and rendered FPS, a discrepancy that is true for both the native and cross-platform apps. The findings we report are indeed factors contributing to the complexity of app development.
Mixed Natural Gas Online Recognition Device Based on a Neural Network Algorithm Implemented by an FPGA
Authors: Jia Tanghao , Guo Tianle , Wang Xuming , Zhao Dan , Wang Chang , Zhang Zhicheng , Lei Shaochong , Liu Weihua , Liu Hongzhong , Li Xin
Published: May 2019

It is a daunting challenge to measure the concentration of each component in natural gas, because different components in mixed gas have cross-sensitivity for a single sensor. We have developed a mixed gas identification device based on a neural network algorithm, which can be used for the online detection of natural gas. The neural network technology is used to eliminate the cross-sensitivity of mixed gases to each sensor, in order to accurately recognize the concentrations of methane, ethane and propane, respectively. The neural network algorithm is implemented by a Field-Programmable Gate Array (FPGA) in the device, which has the advantages of small size and fast response. FPGAs take advantage of parallel computing and greatly speed up the computational process of neural networks. Within the range of 0–100% of methane, the test error for methane and heavy alkanes such as ethane and propane is less than 0.5%, and the response speed is several seconds.
Monitoring of Epoxy-Grouted Bonding Strength Development between an Anchored Steel Bar and Concrete Using PZT-Enabled Active Sensing
Authors: Jiang Jian , Hei Chuang , Feng Qian , Jiang Jinwei
Published: May 2019

Anchored steel bars have been widely used in retrofitting of existing concrete structures. The bonding strength between the anchored steel bar and the concrete is critical to the integrity of the strengthened concrete structure. This paper presents a method to monitor epoxy-grouted bonding strength development by using a piezoceramic-enabled active sensing technique. One concrete beam with an anchored steel bar was involved in the monitoring test, and two concrete beams with six anchored steel bars were used in the pull-out test. To enable the active sensing, a Lead Zirconate Titanate (PZT) patch was bonded to the surface of the exposed end, and piezoceramic smart aggregates were embedded in each concrete specimen. During the monitoring experiment, signals from PZT sensors and smart aggregates were acquired at intervals of 0, 20, 40, 60, 80, and 100 min. In addition, a pull-out test was performed on each of the remaining six anchored steel bars in the two concrete beams, while the signal was recorded in the test. Furthermore, a wavelet packet analysis was applied to analyze the received signal energies to investigate the bonding strength development between the concrete and the anchored steel bar during the epoxy solidification process. The test results demonstrate the effectiveness of the proposed method in monitoring the bonding strength development between the anchored steel bar and the concrete, using the PZT-enabled active sensing.
The Effects of Dimensions on the Deformation Sensing Performance of Ionic Polymer-Metal Composites
Authors: Wang Jiale , Wang Yanjie , Zhu Zicai , Wang Jiahui , He Qingsong , Luo Minzhou
Published: May 2019

As an excellent transducer, ionic polymer-metal composites (IPMCs) can act as both an actuator and a sensor. During its sensing process, many factors, such as the water content, the cation type, the surface electrode, and the dimensions of the IPMC sample, have a considerable impact on the IPMC sensing performance. In this paper, the effect of dimensions focused on the Pd-Au typed IPMC samples with various thicknesses, widths, and lengths that were fabricated and their deformation sensing performances were tested and estimated using a self-made electromechanical sensing platform. In our experiments, we employed a two-sensing mode (both current and voltage) to record the signals generated by the IPMC bending. By comparison, it was found that the response trend was closer to the applied deformation curve using the voltage-sensing mode. The following conclusions were obtained. As the thickness increased, IPMC exhibited a better deformation-sensing performance. The thickness of the sample changed from 50 μm to 500 μm and corresponded to a voltage response signal from 0.3 to 1.6 mV. On the contrary, as the length increased, the sensing performance of IPMC decreased when subjected to equal bending. The width displayed a weaker effect on the sensing response. In order to obtain a stronger sensing response, a thickness increase, together with a length reduction, of the IPMC sample is a feasible way. Also, a simplified static model was proposed to successfully explain the sensing properties of IPMC with various sizes.
Effects of Water Column Variations on Sound Propagation and Underwater Acoustic Communications
Authors: Siddiqui Salman I. , Dong Hefeng
Published: May 2019

Underwater sound propagation is very sensitive to geometric and environmental variations. The geometric variations are the motion of the source and/or receiver, while the environmental variations are due to surface motion and water column variations. In order to reduce the effects of these variations, it is necessary to understand their effects on sound propagation. In this paper, some water column variations are reported, and their effect on the underwater sound propagation is studied. These water column variations were observed during an experiment in the TrondheimFjord on 22 September 2016. Strong amplitude variations were observed in the channel impulse response during the experiment. The Doppler analysis was performed on the channel impulse response, which showed strong Doppler variations. The amplitude and Doppler variations suggested the presence of water column variations. To demonstrate the performance of the communication system, the time reversal combiner was implemented. The system performance was demonstrated by computing the mean squared error between the transmitted signal and the output of the combiner. The performance of the combiner degraded by ~2.5 dB in the presence of water column variations. Due to these variations, the amplitudes of the arrivals changed rapidly, which posed a great challenge for the time reversal combiner. These amplitude variations affected the focusing of the combiner and hence induced intersymbol interference and performance degradation. This work provides an insight into the effects of water column variations on underwater sound propagation and underwater acoustic communications.
A Fine-Grained User-Divided Privacy-Preserving Access Control Protocol in Smart Watch
Authors: Fang Liming , Li Minghui , Zhou Lu , Zhang Hanyi , Ge Chunpeng
Published: May 2019

A smart watch is a kind of emerging wearable device in the Internet of Things. The security and privacy problems are the main obstacles that hinder the wide deployment of smart watches. Existing security mechanisms do not achieve a balance between the privacy-preserving and data access control. In this paper, we propose a fine-grained privacy-preserving access control architecture for smart watches (FPAS). In FPAS, we leverage the identity-based authentication scheme to protect the devices from malicious connection and policy-based access control for data privacy preservation. The core policy of FPAS is two-fold: (1) utilizing a homomorphic and re-encrypted scheme to ensure that the ciphertext information can be correctly calculated; (2) dividing the data requester by different attributes to avoid unauthorized access. We present a concrete scheme based on the above prototype and analyze the security of the FPAS. The performance and evaluation demonstrate that the FPAS scheme is efficient, practical, and extensible.
Fuzzy Logic Type-2 Based Wireless Indoor Localization System for Navigation of Visually Impaired People in Buildings
Authors: AL-Madani Basem , Orujov Farid , Maskeliūnas Rytis , Damaševičius Robertas , Venčkauskas Algimantas
Published: May 2019

The ability to precisely locate and navigate a partially impaired or a blind person within a building is increasingly important for a wide variety of public safety and localization services. In this paper, we explore indoor localization algorithms using Bluetooth Low Energy (BLE) beacons. We propose using the BLE beacon’s received signal strength indication (RSSI) and the geometric distance from the current beacon to the fingerprint point in the framework of fuzzy logic for calculating the Euclidean distance for the subsequent determination of location. According to our results, the fingerprinting algorithm with fuzzy logic type-2 (hesitant fuzzy sets) is fit for use as an indoor localization method with BLE beacons. The average error of localization is only 0.43 m, and the algorithm obtains a navigation precision of 98.2 ± 1%. This precision confirms that the algorithms provide great aid to a visually impaired person in unknown spaces, especially those designed without physical tactile guides, as confirmed by low Fréchet and Hausdorff distance values and high navigation efficiency index (NEI) scores.
A Sub-Regional Calibration Method That Can Accomplish Error Compensation for Photoelectric Scanning Measurement Network
Authors: Zhang Zhenyu , Ren Yongjie , Yang Linghui , Lin Jiarui , Shi Shendong , Zhu Jigui
Published: May 2019

In the measurement process of photoelectric scanning measurement network, the laser surface edge area has lower measurement accuracy than the middle area due to the geometrical distortions of the laser surface of the transmitter. This paper presents a sub-regional calibration method that can accomplish error compensation for the measurement system. Unlike the camera sub-regional calibration, the regional division and identification of the laser surface are more difficult. In this paper, the pitch angle in the transmitter coordinate frame of the spatial point was used as the basis for the division and identification of the laser surface. In the calibration process, the laser surface of the transmitter was divided into different regions and each region was calibrated independently, so that an intrinsic parameters database containing the intrinsic parameters of different regions could be established. Based on the database, the region identification and error compensation algorithm were designed, and comparison experiments were carried out. With the novel calibration method, the measurement accuracy of the system had an obvious upgrade, especially at the edges of the laser surface within a certain measurement area, which could enlarge the effective measurement area of the transmitter and would broaden and deepen the application fields of photoelectric scanning measurement network.
A Secure, Energy- and SLA-Efficient (SESE) E-Healthcare Framework for Quickest Data Transmission Using Cyber-Physical System
Authors: Sharma Ashutosh , Rathee Geetanjali , Kumar Rajiv , Saini Hemraj , Varadarajan Vijayakumar , Nam Yunyoung , Chilamkurti Naveen
Published: May 2019

Due to advances in technology, research in healthcare using a cyber-physical system (CPS) opens innovative dimensions of services. In this paper, the authors propose an energy- and service-level agreement (SLA)-efficient cyber physical system for E-healthcare during data transmission services. Furthermore, the proposed phenomenon will be enhanced to ensure the security by detecting and eliminating the malicious devices/nodes involved during the communication process through advances in the ad hoc on-demand distance vector (AODV) protocol. The proposed framework addresses the two security threats, such as grey and black holes, that severely affect network services. Furthermore, the proposed framework used to find the different network metrics such as average qualifying service set (QSS) paths, mean hop and energy efficiency of the quickest path. The framework is simulated by calculating the above metrics in mutual cases i.e., without the contribution of malevolent nodes and with the contribution of malevolent nodes over service time, hop count and energy constraints. Further, variation of SLA and energy shows their expediency in the selection of efficient network metrics.
Investigation on Mass Sensitivity of N-M Type Electrode Quartz Crystal Microbalance
Authors: Chen Qiao , Huang Xianhe , Pan Wei , Xu Yuan , Fan Zhichao
Published: May 2019

Mass sensitivity plays a crucial role in the practical application of quartz crystal microbalances (QCMs)-based quantitative analysis. n-m type QCMs have many applications, so it is necessary to clarify the relationship between the mass sensitivity and the electrode of the n-m type QCM. The performance of gold-plated films with different electrodes was studied by theoretical calculation and experiment. The results show that the mass sensitivity on the surface of the n electrode and the surface of the m electrode are essentially the same. Meanwhile, the mass sensitivity of n-m type QCMs varies with the diameter of the n and m electrodes. When the diameter of the n electrode is close to half the diameter of the m electrode, mass sensitivity is at maximum value. These results are important for the further designs and applications of n-m type QCMs.
A Case Study of Facial Emotion Classification Using Affdex
Authors: Magdin Martin , Benko Ľubomír , Koprda Štefan
Published: May 2019

This paper focuses on the analysis of reactions captured by the face analysis system. The experiment was conducted on a sample of 50 university students. Each student was shown 100 random images and the student´s reaction to every image was recorded. The recorded reactions were subsequently compared to the reaction of the image that was expected. The results of the experiment have shown several imperfections of the face analysis system. The system has difficulties classifying expressions and cannot detect and identify inner emotions that a person may experience when shown the image. Face analysis systems can only detect emotions that are expressed externally on a face by physiological changes in certain parts of the face.
Routing Protocols for Low Power and Lossy Networks in Internet of Things Applications
Authors: Sobral José V. V. , Rodrigues Joel J. P. C. , Rabêlo Ricardo A. L. , Al-Muhtadi Jalal , Korotaev Valery
Published: May 2019

The emergence of the Internet of Things (IoT) and its applications has taken the attention of several researchers. In an effort to provide interoperability and IPv6 support for the IoT devices, the Internet Engineering Task Force (IETF) proposed the 6LoWPAN stack. However, the particularities and hardware limitations of networks associated with IoT devices lead to several challenges, mainly for routing protocols. On its stack proposal, IETF standardizes the RPL (IPv6 Routing Protocol for Low-Power and Lossy Networks) as the routing protocol for Low-power and Lossy Networks (LLNs). RPL is a tree-based proactive routing protocol that creates acyclic graphs among the nodes to allow data exchange. Although widely considered and used by current applications, different recent studies have shown its limitations and drawbacks. Among these, it is possible to highlight the weak support of mobility and P2P traffic, restrictions for multicast transmissions, and lousy adaption for dynamic throughput. Motivated by the presented issues, several new solutions have emerged during recent years. The approaches range from the consideration of different routing metrics to an entirely new solution inspired by other routing protocols. In this context, this work aims to present an extensive survey study about routing solutions for IoT/LLN, not limited to RPL enhancements. In the course of the paper, the routing requirements of LLNs, the initial protocols, and the most recent approaches are presented. The IoT routing enhancements are divided according to its main objectives and then studied individually to point out its most important strengths and weaknesses. Furthermore, as the main contribution, this study presents a comprehensive discussion about the considered approaches, identifying the still remaining open issues and suggesting future directions to be recognized by new proposals.
Development and Deployment of Air-Launched Drifters from Small UAS
Authors: Swenson Sara , Argrow Brian , Frew Eric , Borenstein Steve , Keeler Jason
Published: May 2019

Supercell thunderstorms can form extremely dangerous and destructive tornadoes. While high fidelity supercell simulations have increased the understanding of supercell mechanics to help determine how and when tornadoes form, there is a lack of targeted, in situ measurements taken aboveground in supercells to validate these simulations. Pseudo-Lagrangian drifters (PLDs) are atmospheric probes that can be used to attain thermodynamic measurements in areas that are difficult or dangerous to access, such as from within supercells. Of particular interest in understanding tornadogenesis is the rear-flank downdraft (RFD). However, strong outflow winds behind the rear-flank gust front (RFGF) make the RFD particularly difficult to access with balloon-borne sensors launched from the ground. A specific type of PLD, an air-launched drifter (ALD) that is released from unmanned aircraft systems (UAS), can be used to access RFD inflows, present at higher altitudes. Results from initial tests of ALDs are shown, along with results from a ground-released PLD test during a supercell intercept in the Oklahoma Panhandle on 12 June 2018. In characterization tests performed at the 2018 International Society for Atmospheric Research using Remotely piloted Aircraft (ISARRA) flight week, it was found that the ALD sensor system performs reasonably well against industry standards. However, improvements will be made to increase the aspiration of the sensor.
A Novel Health Indicator Based on Cointegration for Rolling Bearings’ Run-To-Failure Process
Authors: Li Hongru , Li Yaolong , Yu He
Published: May 2019

The extraction of rolling bearings’ degradation features has been developed for decades. However, the degradation features always present different trends of different run-to-failure data. To find a consistent indicator of different data will be helpful to establish a general model and explore the nature of bearings’ degradation. In this study, we have found there is a trend of similarity between the energy and complexity features. By using the cointegration test, we found the two kinds of features exhibit a certain degree of cointegration relationship. Fused by the cointegration method, we have obtained a novel health indicator which can depict different run-to-failure data in a unified way. The difference between the energy features and complexity features can be explained by the novel health indicator. The indicator has “two-stage” characters. The first stage is the zero-line stage and the second stage is the quickly raise stage, which presents like an exponential function. It is easy to think about using an exponential degradation model to model this indicator. Next, we have compared the indicator to root mean square (RMS) by using the exponential degradation model. It shows that the indicator is more suitable for the exponential degradation model. In this paper, we used eleven run-to-failure data to verify the generality and “two-stage” characters of the proposed indicator. The result shows that the novel indicator is general and effective and that it will promote the development of bearings’ prognostics.
Identifying Traffic Context Using Driving Stress: A Longitudinal Preliminary Case Study
Authors: Bitkina Olga Vl. , Kim Jungyoon , Park Jangwoon , Park Jaehyun , Kim Hyun K.
Published: May 2019

Many previous studies have identified that physiological responses of a driver are significantly associated with driving stress. However, research is limited to identifying the effects of traffic conditions (low vs. high traffic) and road types (highway vs. city) on driving stress. The objective of this study is to quantify the relationship between driving stress and traffic conditions, and driving stress and road types, respectively. In this study, electrodermal activity (EDA) signals for a male driver were collected in real road driving conditions for 60 min a day for 21 days. To classify the levels of driving stress (low vs. high), two separate models were developed by incorporating the statistical features of the EDA signals, one for traffic conditions and the other for road types. Both models were based on the application of EDA features with the logistic regression analysis. City driving turned out to be more stressful than highway driving. Traffic conditions, defined as traffic jam also significantly affected the stress level of the driver, when using the criteria of the vehicle speed of 40 km/h and standard deviation of the speed of 20 km/h. Relevance to industry: The classification results of the two models indicate that the traffic conditions and the road types are important features for driving stress and its related applications.
An Improved Step-Type Liquid Level Sensing System for Bridge Structural Dynamic Deflection Monitoring
Authors: Ye Xijun , Sun Zhuo , Cai Xu , Mei Liu
Published: May 2019

Real-time and accurate monitoring of dynamic deflection is of great significance for health monitoring and condition assessment of bridge structures. This paper proposes an improved step-type liquid level sensing system (LLSS) for dynamic deflection monitoring. Layout of straight-line-type pipeline is replaced by step-type pipeline in this improved deflection monitoring system, which can remove the interference of the inclination angle on the measurement accuracy and is applicable for dynamic deflection monitoring. Fluid dynamics are first analyzed to demonstrate that measurement accuracy is interfered with by the fluid velocity induced by structural vibration, and ANSYS-FLOTRAN is applied for analyzing the influence range caused by the turbulent flow. Finally, a step-type LLSS model is designed and experimented with to verify the influence of the three key parameters (initial displacement excitation, step height, and distance from the measurement point to the elbow) on the measurement accuracy, and the reasonable placement scheme for the measurement point is determined. The results show that the measurement accuracy mainly depends on the turbulent flow caused by step height. The measurement error gets smaller after about 1.0 m distance from the elbow. To ensure that the measurement error is less than 6%, the distance between the measurement point and the elbow should be larger than 1.0 m.
Modeling and Experimental Study for Online Measurement of Hydraulic Cylinder Micro Leakage Based on Convolutional Neural Network
Authors: Guo Yuan , Zeng Yinchuan , Fu Liandong , Chen Xinyuan
Published: May 2019

Internal leakage is the most common failure of hydraulic cylinder; when it increases, it decreases volumetric efficiency, pressure and speed of the hydraulic cylinder, and can seriously affect the normal operation of the hydraulic cylinder, so it is important to measure it, especially to measure it online. Firstly, the principle of internal leakage online measurement is proposed, including the online measurement system, the fixed mode of the strain gauge and the mathematical model of the flow-strain signal conversion. Secondly, an experimental system is established to collect internal leakages and strain values, and the data is processed. Finally, the convolutional neural network (CNN), BP neural network (BPNN), Radial Basis Function Network (RBF), and Support Vector Regression (SVR) are used to predict the hydraulic cylinder leakage; the comparison of experimental results show that the CNN has high accuracy and high efficiency. This study provides a new idea for online measurement of small flow on other hydraulic components.
Performance Analysis of Ionospheric Scintillation Effect on P-Band Sliding Spotlight SAR System
Authors: Yu Lei , Zhang Yongsheng , Zhang Qilei , Ji Yifei , Dong Zhen
Published: May 2019

The space-borne P-band synthetic aperture radar (SAR) maintains excellent penetration capability. However, the low carrier frequency restricts its imaging resolution. The sliding spotlight mode provides an operational solution to meet the requirement of high imaging resolution in P-band SAR design. Unfortunately, the space-borne P-band SAR will be inevitably deteriorated by the ionospheric scintillation. Compared with the stripmap mode, the sliding spotlight SAR will suffer more degradation when operating in the scintillation active regions due to its long integration time and complex imaging geometry. In this paper, both the imaging performance and scintillation effect for P-band sliding spotlight mode are studied. The theoretical analysis of scintillation effect is performed based on a refined model of the two-frequency and two-position coherence function (TFTPCF). A novel scintillation simulator based on the reverse back-projection (ReBP) algorithm is proposed to generate the SAR raw data for sliding spotlight mode. The proposed scintillation simulator can also be applied to predict the scintillation effect for other multi-mode SAR systems such as terrain observation by progressive scans (TOPS) and ScanSAR. Finally, a group of simulations are carried out to validate the theoretical analysis.
LightSit: An Unobtrusive Health-Promoting System for Relaxation and Fitness Microbreaks at Work
Authors: Ren Xipei , Yu Bin , Lu Yuan , Zhang Biyong , Hu Jun , Brombacher Aarnout
Published: May 2019

Physical inactivity and chronic stress at work increase the risks of developing metabolic disorders, mental illnesses, and musculoskeletal injuries, threatening office workers’ physical and psychological well-being. Although several guidelines and interventions have been developed to prevent theses subhealth issues, their effectiveness and health benefits are largely limited when they cannot match workday contexts. This paper presents LightSit, a health-promoting system that helps people reduce physically inactive behaviors and manage chronic stress at work. LightSit comprises a sensor mat that can be embedded into an office chair for measuring a user’s sitting posture and heart rate variability and a lighting display that is integrated into a monitor stand to present information unobtrusively, facilitating fitness and relaxation exercises during microbreaks. Following the showroom approach, we evaluated LightSit during a public exhibition at Dutch Design Week 2018. During the eight days of the exhibition, we observed more than 500 sessions of experiences with healthy microbreaks using our prototype. Semistructured interviews were conducted with 50 participants who had office-based jobs and had experienced LightSit. Our qualitative findings indicated the potential benefits of LightSit in facilitating health-promoting behaviors during office work. Based on the insights learned from this study, we discuss the implications for future designs of interactive health-promoting systems.
The Categorized and Invisible: The Effects of the ‘Border’ on Women Migrant Transit Flows in Mexico
Authors: Angulo-Pasel Carla
Published: May 2019

In an increasingly globalized world, border control is continuously changing. Nation-states grapple with ‘migration management’ and maintain secure borders against ‘illegal’ flows. In Mexico, borders are elusive; internal and external security is blurred, and policies create legal categories of people whether it is a ‘trusted’ tourist or an ‘unauthorized’ migrant. For the ‘unauthorized’ Central American woman migrant trying to achieve safe passage to the United States (U.S.), the ‘border’ is no longer only a physical line to be crossed but a category placed on an individual body, which exists throughout her migration journey producing vulnerability as soon as the Mexico–Guatemala boundary is crossed. Based on policy analysis and fieldwork, this article argues that rather than protecting ‘unauthorized’ migrants, which the Mexican government narrative claims to do, border policies imposed by the state legally categorize female bodies in clandestine terms and construct violent relationships. This embodied illegality creates forced invisibility, further marginalizing women with respect to finding work, and experiences of sexual violence and abuses by migration actors. The analysis focuses on three areas: the changing definition of ‘borders’; the effects of categorization and multiple vulnerabilities on Central American women; and the dangers caused by forced invisibility.
Effects of Strength Training on Body Composition in Young Male Professional Soccer Players
Authors: Suarez-Arrones Luis , Lara-Lopez Pilar , Torreno Nacho , Saez de Villarreal Eduardo , Di Salvo Valter , Mendez-Villanueva Alberto
Published: May 2019

The present prospective cohort study investigated changes in body composition (BC) in young male football players (n = 18, 16.1 ± 0.8 years; 181.0 ± 0.1 cm; 71.3 ± 4.9 kg) after combined football and strength training (ST) during a whole in-season period (26 weeks). BC was measured at whole-body absolute and regional levels by dual-energy X-ray absorptiometry in eighteen players at the beginning and at the end of the competitive period. The ST was organized into three different session types: ST in the gym, specific ST on the field, and individual ST (weak points). The results of the present study indicated that fat-free mass (FFM) was substantially higher following the competitive period (5.1% ± 1.2%), while percentage of fat showed no changes during the competitive period. At the regional level, arms’ and legs’ FFM increased at the end of the season, and bone mineral content (BMC) and density (BMD) increased in arms, legs, pelvis, thoracic spine, and lumbar spine. In conclusion, within the limitation of the potential positive impact of growth and/or maturation, present results seem to indicate that an ST program that supplements football-related training sessions could be an effective option to increase FFM, BMC, and BMD at both whole-body and regional level across the competitive season in young male professional football players.
Effects of Maturation on Lower Limb Neuromuscular Asymmetries in Elite Youth Tennis Players
Authors: Madruga-Parera Marc , Romero-Rodríguez Daniel , Bishop Chris , Beltran-Valls Maria Reyes , Latinjak Alex T. , Beato Marco , Fort-Vanmeerhaeghe Azahara
Published: May 2019

Neuromuscular asymmetries have been previously associated with reduced performance. Similarly, maturation has shown that youth athletes may experience a loss of motor control, which could also lead to compromised physical performance. The present study aimed to evaluate and quantify the level of asymmetry among chronological and maturational groups. Forty-one youth tennis players performed the single leg countermovement jump (SLCMJ), star excursion balance test (SEBT) and a change of direction speed (CODS) test. Differences were found between the strongest and weakest limbs across all tests (p < 0.001), and also for SEBT in the posteromedial direction (p = 0.02), SEBT composite score (p < 0.01) in maturation groups, and for SEBT posterolateral direction (p = 0.03) and SEBT composite score (p = 0.01) in chronological groups. The SLCMJ showed the largest inter-limb asymmetries for the circa peak height velocity (PHV) group (19.31 ± 12.19%) and under-14 (U14) group (17.55 ± 9.90%). Chronological and maturation groups followed similar trends for inter-limb asymmetries, but the biological index showed larger asymmetry scores in the jumping test at PHV compared to that found in the chronological group (U14). These results show that inter-limb differences may be heightened during PHV. Practitioners can use this information to inform the decision-making process when prescribing training interventions in youth tennis players.
Setting Alarm Thresholds in Measurements with Systematic and Random Errors
Authors: Burr Tom , Bonner Elisa , Krzysztoszek Kamil , Norman Claude
Published: May 2019

For statistical evaluations that involve within-group and between-group variance components (denoted σ W 2 and σ B 2 , respectively), there is sometimes a need to monitor for a shift in the mean of time-ordered data. Uncertainty in the estimates σ ^ W 2 and σ ^ B 2 should be accounted for when setting alarm thresholds to check for a mean shift as both σ W 2 and σ B 2 must be estimated. One-way random effects analysis of variance (ANOVA) is the main tool for analysing such grouped data. Nearly all of the ANOVA applications assume that both the within-group and between-group components are normally distributed. However, depending on the application, the within-group and/or between-group probability distributions might not be well approximated by a normal distribution. This review paper uses the same example throughout to illustrate the possible approaches to setting alarm limits in grouped data, depending on what is assumed about the within-group and between-group probability distributions. The example involves measurement data, for which systematic errors are assumed to remain constant within a group, and to change between groups. The false alarm probability depends on the assumed measurement error model and its within-group and between-group error variances, which are estimated while using historical data, usually with ample within-group data, but with a small number of groups (three to 10 typically). This paper illustrates the parametric, semi-parametric, and non-parametric options to setting alarm thresholds in such grouped data.
Incorporating the Concepts of Sharing-In and Sharing-Out in CSR: Australian Consumers’ Perspective
Authors: Amin-Chaudhry Anjum , Pomering Alan , Johnson Lester W.
Published: May 2019

Corporate social responsibility (CSR) is based on attending to concerns beyond a corporation’s shareholders. This concern embraces the concepts of sharing and caring for others. Logically then, the literature on sharing might inform theory and practice around CSR initiatives. To date, however, theory around the theme of sharing is absent from extant CSR literature, and, presumably, it is omitted as a perspective on CSR practice. This paper addresses this gap by empirically investigating consumers’ responses to different types of sharing involved in a range of CSR initiatives. We test the sharing theory to provide generalizable conclusions. Data was collected via an online panel of Australian consumers. Findings reveal two distinct types of sharing across different CSR initiatives: Sharing-in and sharing-out. Sharing-in CSR initiatives are those perceived as being adopted for the benefit of the firm’s direct stakeholders and aimed at providing a direct, reciprocal benefit to the firm. Conversely, sharing-out initiatives are perceived as providing wider and unconditional support to all, irrespective of their proximity to the firm. This research makes an original contribution to the CSR literature by embedding the notion of sharing within the management of CSR initiatives. The sharing perspective adds to knowledge and may assist managers when developing CSR initiatives, and how those initiatives might be perceived by a firm’s relevant stakeholders.