bluuebunny/crossref_metadata_2025 huggingface dataset:
Landslide Prediction with Model Switching
Authors: Utomo Darmawan , Chen Shi-Feng , Hsiung Pao-Ann
Published: May 2019

Landslides could cause huge damages to properties and severe loss of lives. Landslides can be detected by analyzing the environmental data collected by wireless sensor networks (WSNs). However, environmental data are usually complex and undergo rapid changes. Thus, if landslides can be predicted, people can leave the hazardous areas earlier. A good prediction mechanism is, thus, critical. Currently, a widely-used method is Artificial Neural Networks (ANNs), which give accurate predictions and exhibit high learning ability. Through training, the ANN weight coefficients can be made precise enough such that the network works in analogy to a human brain. However, when there is an imbalanced distribution of data, an ANN will not be able to learn the pattern of the minority class; that is, the class having very few data samples. As a result, the predictions could be inaccurate. To overcome this shortcoming of ANNs, this work proposes a model switching strategy that can choose between different predictors, according to environmental states. In addition, ANN-based error models have also been designed to predict future errors from prediction models and to compensate for these errors in the prediction phase. As a result, our proposed method can improve prediction performance, and the landslide prediction system can give warnings, on average, 44.2 min prior to the occurrence of a landslide.
Trends and Research Issues of Augmented Reality Studies in Architectural and Civil Engineering Education—A Review of Academic Journal Publications
Authors: Diao Pei-Huang , Shih Naai-Jung
Published: May 2019

Architectural and civil engineering (ACE) education is inextricably connected to real-world practice. The application of augmented reality (AR) technology can help to establish a link between virtual and real-world information for students. Studies of applying AR in ACE education have increased annually, and numerous research have indicated that AR possesses immense application potential. To address and analyze pertinent research issues, published studies in the Scopus database were explored, and revealed that problems persist and are worthy of attention, such as the selection of system types and devices, the application of research methods, and appropriate learning strategies and teaching methods. Courses with objective grading standards should be given priority in AR experimental courses for a meticulous investigation of AR influence on students’ learning outcomes and ultimately improvement of classroom quality. Suitable types of AR systems should be selected based on course content, prior to the design and development of the system. It is recommended to develop markerless systems for a larger application range to benefit students with additional convenience. Systems can also be accompanied by functions, such as instant online assessments, synchronized assessments, and exchange capabilities to assist learning what has been taught and develop critical thinking abilities. The combination of AR and building information modeling (BIM) in architectural and civil practice, which has immense application potential, has become an emerging research trend. Collaboration between academics and practice should be enhanced with roles and knowledge of instructors, engineers, designers, and computer experts integrated for an optimal connection between general pedagogy and domain-specific learning. Teaching methods that emphasize “locations”, as well as “roles”, can be adopted in order to create a superior reality learning environment with diversified learning methods. The trends and research have become an integration and collaboration issue that should be performed interactively with pedagogical findings, and resources integrated across roles, fields, and university departments.
Statistical Patterns of Transmission Losses of Low-Frequency Sound in Shallow Sea Waveguides with Gaussian and Non-Gaussian Fluctuations
Authors: Zhu Fengqin , Gulin Oleg E. , Yaroshchuk Igor O.
Published: May 2019

Based on the local mode method, the problem of the average intensity (transmission loss) behavior in shallow waveguides with losses in the bottom and fluctuations of the speed of sound in water is considered. It was previously shown that the presence in a waveguide with absorbing penetrable bottom of 2D random inhomogeneities of the speed of sound leads to the appearance of strong fluctuations in the acoustic field already at relatively small distances from the sound source. One of the most important and interesting manifestations of this is the slowing down of the average intensity of the acoustic field compared with a waveguide, which has no such random inhomogeneities of the speed of sound. This paper presents the results of a numerical analysis of the decay of the average field intensity in the presence of both Gaussian and non-Gaussian fluctuations in the speed of sound. It is shown that non-Gaussian fluctuations do not fundamentally change the conclusion about reducing losses during the propagation of a sound signal but can enhance this effect.
Species of the Genus Salix L.: Biochemical Screening and Molecular Docking Approach to Potential Acetylcholinesterase Inhibitors
Authors: Gligorić Emilia , Igić Ružica , Suvajdžić Ljiljana , Grujić-Letić Nevena
Published: May 2019

The genus Salix includes about 500 different, mainly woody species with potentially significant medicinal values. The aim of this study was to evaluate the chemical composition and antioxidant activity of little-studied bark and leaves extracts of seven different species of the genus Salix, and to examine the acetylcholinesterase (AChE) inhibitory potential of selected compounds. The extracts were characterized by High Pressure Liquid Chromatography (HPLC). Total phenolics and flavonoids content was determined spectrophotometrically and the antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH•) and hydroxyl radical (•OH) scavenging assays. Molecular docking studies were conducted in order to elucidate the interaction and binding affinity between selected compounds of willow bark and leaves against AChE. The major components in bark and leaves of most of the species were rutin (1.26–22.09 mg/g), salicin (1.62–17.33 mg/g), chlorogenic acid (0.74–7.53 mg/g) and epicatechin (0.71–4.83 mg/g). The latter three compounds demonstrated significant inhibitory potential against AChE in docking studies. All extracts exhibited notable antioxidant activity as scavengers of both DPPH• and •OH. The obtained results indicate that willow species other than those in commercial use, and not only bark, but willow leaves as well, could be utilized as sources of valuable phytocompounds with antioxidant and neuroprotective properties.
Automatic Initialization Methods for Photonic Components on a Silicon-Based Optical Switch
Authors: Tondini Stefano , Castellan Claudio , Medina Manuel Alessandro , Pavesi Lorenzo
Published: May 2019

In this work we showed the optimization of the spectral response of several optical elements in a silicon-based optical switch. Integrated thermal resistors induced a local heating of the components. The temperature increase, in turn, caused a thermal shift of the optical response of the component. In this manner, we aligned interleavers and micro-ring resonators to the International Telecommunication Union (ITU) channels, by using a stochastic method named Globalized Bounded Nelder-Mead (GBNM) to determine the proper temperatures. The optimization engine relied on the optical feedback from on-chip monitor photodiodes to drive these photonic elements into the wanted functioning condition. This method is suited for restoring the spectral response of optical elements impaired by fabrication inaccuracies. In the same way, it can be applied to tune in resonance active components, whose transfer function has one or more local optima. We proved the reliability of the GBNM method for the optimization of an integrated optical switch, with more than thousand optical components, each one interfaced with a thermal resistor driven by a dedicated electronic circuit. On the one hand, the GBNM guaranteed the automatic alignment of all active components on the chip, over multiple instances. On the other hand, the method allowed for the proper working of such a complex device.
Implementation of R&D Results and Industry 4.0 Influenced by Selected Macroeconomic Indicators
Authors: Švarcová Jena , Urbánek Tomáš , Povolná Lucie , Sobotková Eliška
Published: May 2019

Successful timing of INDUSTRY 4.0 projects in businesses can be disrupted by the coming of a recession. The authors assume a close link between INDUSTRY 4.0 and research and development (R&D) projects. R&D projects are statistically internationally monitored and have a significant impact on European Union economic policies. This article explores the impact of the two economic recessions in 2009 and 2012–2013 on the number of R&D entities and human resources involved in R&D in the Czech Republic. The method of multivariate statistics with dummy variables was used. Research has shown that different sectors (business sector, government sector, higher education sector, and non-profit sector) show a different development of the number of R&D entities in times of economic crisis. The research findings indicate that current European Union grant support, tax relief, and other specific factors appear to be more important for the development of R&D projects in the Czech Republic than the effects of economic recession. In terms of longer time horizons, however, the effects of the business cycle cannot be ignored. In order to predict economic development, enterprises and other subjects can use leading macroeconomic indicators.
An Approach to Supporting the Selection of Maintenance Experts in the Context of Industry 4.0
Authors: Patalas-Maliszewska Justyna , Kłos Sławomir
Published: May 2019

(1) Background: In recent years, many studies regarding the issues of improving the management and effectiveness of the maintenance department of manufacturing companies, in the context Industry 4.0, have been published. This makes it necessary to establish a research gap in the approach to obtaining support in realising management tasks in the maintenance area in the selection of appropriate employees to perform the given activities. (2) Methods: This article uses literature studies and empirical research results from manufacturing companies, in order to determine the approach in supporting the selection of maintenance experts. In the approach, the method used—which is based on rules should there be future any formalisation of the data—is also the Fuzzy Analytic Hierarchy Process (FAHP), which analyses the importance of a given competence, within a manufacturing resource, to undertake repairs. (3) Results: The innovative approach towards the selection of expert workers in a maintenance department is created, in part, in the form of an implemented web-application. The novelty of the “maintenance expert selection map", so-called, is the provision of formal procedures for describing the competence of each maintenance worker and defining the best “state of nature”. (4) Conclusions: In the research that is presented here, the practicality for maintenance managers in the “maintenance expert selection map" was established. This map describes the competence of workers for selecting them for repair work within a given manufacturing resource; the scope of employee training was also determined in this research.
A New Plasma Surface Alloying to Improve the Wear Resistance of the Metallic Card Clothing
Authors: Wei Dongbo , Li Fengkun , Li Shuqin , Chen Xiaohu , Ding Feng , Zhang Pingze , Wang Zhangzhong
Published: May 2019

A new surface strengthening process: Plasma surface chromizing was implemented on the metallic card clothing to improve its wear resistance based on double glow plasma surface metallurgy technology. A chromizing coating was prepared in the process, which consisted of a deposited layer and diffusion layer. The surface morphologies, microstructure, phase composition, and hardness were analyzed in detail. The friction behaviors of the metallic card clothing before and after plasma surface alloying were comparatively analyzed under various sliding speeds at room temperature. The results showed that: 1. The chromizing coating on the surface of metallic card clothing was dense and homogeneous without defects, and the metallic card clothing still maintained its integrity and sharpness. 2. The chromizing coating consist of [Fe,Cr], Cr, Cr23C6, and Cr7C3, which contribute to the high hardness. 3. The average microhardness of metallic card clothing increased from 365.4 HV0.05 to 564.9 HV0.05 after plasma surface chromizing. Nano hardness of the chromizing coating was approximately 1.87 times than the metallic card clothing. 4. At various sliding velocities of 2 m/min, 4 m/min, and 6 m/min, the specific wear rates of metallic card clothing were 16.38, 9.06 and 6.26 × 10−4·mm3·N−1·m−1, and the specific wear rates of metallic card clothing after plasma surface chromizing were 2.91, 3.30, and 2.95 × 10−4·mm3·N−1·m−1. Furthermore, the wear mechanism of the chromizing coating gradually changed from adhesive wear to abrasive wear as the sliding velocity increased. The results indicate that the wear resistance of metallic card clothing was improved obviously after plasma surface chromizing.
Variation of Zooplankton Mean Volume Backscattering Strength from Moored and Mobile ADCP Instruments for Diel Vertical Migration Observation
Authors: Dwinovantyo Angga , Manik Henry M. , Prartono Tri , Susilohadi Susilohadi , Mukai Tohru
Published: May 2019

Zooplankton can be detected by using acoustic Doppler current profiler (ADCP) instruments through acquiring the mean volume backscattering strength (MVBS) data. However, the precision of the backscattered signal measured by single ADCP measurement has a limitation in the MVBS variation of zooplankton. The objectives of this study were to analyze the MVBS and vertical velocity from ADCPs at the same time and location for zooplankton’s daily vertical migration (DVM) observation. Measurements were conducted in Lembeh Strait, North Sulawesi, Indonesia. Instruments used included a moored ADCP 750 kHz and a mobile ADCP 307.2 kHz. High MVBS value was found at 11.5–16 m depths and was identified as the sound scattering layer (SSL). The DVM patterns in the SSL displayed significant differences over time and had good relationships with the diurnal cycle. Theoretical target strength (TS) from the scattering models based on a distorted-wave Born approximation (DWBA) was estimated for Oithona sp. and Paracalanus sp.; the two dominant species found in the observed area. However, ΔMVBS and ΔTS proved that the dominant zooplankton species were not the main scatterers. The strong signal in SSL was instead caused by the schools of various zooplankton species.
Nonlinear Blind Source Separation and Fault Feature Extraction Method for Mining Machine Diagnosis
Authors: Ding Hua , Wang Yiliang , Yang Zhaojian , Pfeiffer Olivia
Published: May 2019

Mining machines are strongly nonlinear systems, and their transmission vibration signals are nonlinear mixtures of different kinds of vibration sources. In addition, vibration signals measured by the accelerometer are contaminated by noise. As a result, it is inefficient and ineffective for the blind source separation (BSS) algorithm to separate the critical independent sources associated with the transmission fault vibrations. For this reason, a new method based on wavelet de-noising and nonlinear independent component analysis (ICA) is presented in this paper to tackle the nonlinear BSS problem with additive noise. The wavelet de-noising approach was first employed to eliminate the influence of the additive noise in the BSS procedure. Then, the radial basis function (RBF) neural network combined with the linear ICA was applied to the de-noised vibration signals. Vibration sources involved with the machine faults were separated. Subsequently, wavelet package decomposition (WPD) was used to extract distinct fault features from the source signals. Lastly, an RBF classifier was used to recognize the fault patterns. Field data acquired from a mining machine was used to evaluate and validate the proposed diagnostic method. The experimental analysis results show that critical fault vibration source component can be separated by the proposed method, and the fault detection rate is superior to the linear ICA based approaches.
The Use of a Special Stereoscopic Microscope Attachment for the Sieve Analysis of Aggregate in Concrete
Authors: Wawrzeńczyk Jerzy , Molendowska Agnieszka
Published: May 2019

The article proposes an innovative technique that allows relatively easy distinction of sand and aggregate particles on the surface image of a concrete specimen. The concept of the proposed approach involves the use of a new method of illuminating carefully polished surfaces of specimens. This is possible owing to a special attachment mounted on the lens of a stereoscopic microscope. The obtained digital image of the specimen, after being converted into a binary image, was subjected to a standard numerical analysis to determine the parameters characterizing the aggregate, i.e., particle size distribution (grading curve), maximum dimension, and shape. Two application examples are presented for analysing sand particle size and for determining the cement paste content in the concrete. The results obtained with the proposed technique were very promising and offer great potential for its practical implementation.
Reconstruction of Simulated Cylindrical Defects in Acrylic Glass Plate Using Pulsed Phase Thermography
Authors: Tomić Ljubiša , Damnjanović Vesna , Dikić Goran , Milanović Bojan
Published: May 2019

The results of testing of acrylic glass, in which cylindrical defects were simulated at different depths by applying Pulsed Phase Thermography, are presented in the paper. To ensure better visibility of the simulated defects, suitable thermal images were selected and then processed by using two different procedures. In the first procedure, reduced thermal image sequences were generated by uniform extraction from the basic sequence, to enable analysis at different sampling frequencies. The second procedure was based on the application of a window function, which ensured that only uniformly selected thermal images took part in the evaluation of the basic sequence. The remaining thermal images were not used, but they did participate in the determination of the length of the analyzed sequence; in other words, their existence was registered through the number of samples used in Fast Fourier Transformation. The second procedure yielded much better results with regard to the estimation of the shape of a defect and the depth at which it was located. To provide better insight into the development of the thermal process in the defect area, an additional analysis of pixel intensity variation in the time domain was undertaken.
Wave Force Characteristics of Large-Sized Offshore Wind Support Structures to Sea Levels and Wave Conditions
Authors: Jeong Youn-Ju , Park Min-Su , Kim Jeongsoo , Song Sung-Hoon
Published: May 2019

This paper presents the results of wave force tests conducted on three types of offshore support structures considering eight waves and three sea levels to investigate the corresponding wave forces. As a result of this study, it is found that the occurrence of shoaling in shallow water induces a significant increase of the wave force. Most of the test models at the shallow water undergo a nonlinear increase of the wave force with higher wave height increasing. In addition, the larger the diameter of the support structure within the range of this study, the larger the diffraction effect is, and the increase in wave force due to shoaling is suppressed. Under an irregular wave at the shallow water, the wave force to the long-period wave tends to be slightly higher than that of the short period wave since the higher wave height component included in the irregular wave has an influence on the shoaling. In addition, it is found that the influence of shoaling under irregular wave becomes more apparent in the long period.
Effect of (Pr+Ce) Additions on Microstructure and Mechanical Properties of AlSi5Cu1Mg Alloy
Authors: Fang Miao-Miao , Yan Hong , Song Xian-Chen , Sun Yong-Hui
Published: May 2019

The microstructure and mechanical properties of AlSi5Cu1Mg alloy with (Pr+Ce) addition were investigated by optical microscopy (OM), energy dispersive spectroscopy (EDS), and scanning electron microscopy (SEM). The results demonstrated that the rare earth (Pr+Ce) addition refined the grain. The long needle-like eutectic Si phases turned to granual. The secondary dendrite arm spacing (SADS) of the primary α-Al phase with the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy reached the minimum value, which decreased by 50.2%. The mean length and the aspect ratio of the eutectic Si decreased by 78.8% and 67.4%. The ultimate tensile strength (UTS), the microhardness, and the breaking elongation of the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy reached a maximum, and increased by 21.5%, 21.7%, and 8.0% compared to the AlSi5Cu1Mg alloy. The fracture examinations manifested in cleaved surfaces and brittle fracture areas, which were seen from the AlSi5Cu1Mg+0.6 wt.% (Pr+Ce) alloy. The number of dimples slightly increased.
Mechanical Properties of Desert Sand-Based Fiber Reinforced Concrete (DS-FRC)
Authors: Che Jialing , Wang Dan , Liu Haifeng , Zhang Yixin
Published: May 2019

This paper presents the study on the properties of high-ductility fiber reinforced concrete made with desert sand from China’s Mu Us desert. The workability and uniaxial tensile/compression properties of undisturbed desert sand-based fiber reinforced concrete (DS-FRC) with the change of water-to-binder ratio (W/B), sand-to-binder ratio (S/B) and desert sand replacement rate (DSRR) were experimentally investigated. Experimental results reveal that the appropriate W/B and desert sand content are conducive to the workability development of DS-FRC. The uniaxial tension/compression properties of DS-FRC are mainly affected by the W/B. Especially, the highest uniaxial tensile/compression stresses and corresponding strains are obtained at the W/B of 0.29. The S/B has similar effects on the uniaxial tensile/compression properties, and an S/B of 0.36 is the optimal ratio. In terms of the DSRR, it shows less effect on the uniaxial tensile/compression properties, even for the DSRR of 100%. The results of the tests indicate that undisturbed desert sand can be used as silica sand in high-ductility fiber reinforced concrete.
Modeling a Dual-Mode Controller Design for a Quasi-Resonant Flyback Converter
Authors: Chuang Ching-Chun , Hua Chih-Chiang , Huang Chong-Yu , Jhou Li-Kai
Published: May 2019

The proposed system can overcome the disadvantage of a high peak current in quasi-resonant fly-back (QRF) converters when operated under heavy load conditions. The operating mode and control scheme of a QRF converter with dual-mode control were established and analyzed. The dual-mode control scheme not only enabled a valley-switching detection technique that satisfied the zero-voltage switching condition but also provided a constant frequency mechanism to reduce the conduction loss in QRF converters when operated in a continuous conduction mode and under heavy load conditions. The small-signal equivalent circuit model of QRF converter circuits was constructed using an average approximation method. The technological advancement of a QRF converter with a dual-mode controller was presented in this study. The circuit simulation result of the proposed QRF converter with a mix control scheme proved that the derived circuit component parameters meet the requirements of the converter.
Utilizing Sequential Control Scheme to Stabilize Squeezed Vacuum States
Authors: Tian Long , Sun Xiaocong , Wang Qingwei , Wang Jinrong , Yao Wenxiu , Wang Junping , Zheng Yaohui , Peng Kunchi
Published: May 2019

We report on a sequential control scheme to realize a steady, quasi-continuous output of squeezed vacuum states, which eliminates the influence of the seed beam on the squeezing strength. The scheme, originating from time-division multiplexing, separates the generation process from the locking process. We confirm that the sequential control scheme does not reduce the squeezing strength and that the setup operates stably for a 3-h running test, with a duty ratio of 80% and cycle time of 5 s. Therefore, the sequential control scheme opens up a new path of manipulating squeezed vacuum states.
Fractionation of Lignocellulosic Biomass by Selective Precipitation from Ionic Liquid Dissolution
Authors: Lara-Serrano Marta , Morales-delaRosa Silvia , Campos-Martín Jose M. , Fierro Jose L. G.
Published: May 2019

We propose the treatment of barley straw with 1-ethyl-3-methylimidazolium acetate [EMIMAcO] ionic liquids (ILs) and subsequent precipitation with antisolvent mixtures, thus allowing the separation of the sugar-rich fractions (cellulose and hemicellulose) from the lignin fraction. For this purpose, different concentration ranges of acetone:water antisolvent mixtures were studied. In all cases, a high recovery percentage and a high and effective separation of fractions was achieved for 1:1 acetone:water. The fractionated lignocellulosic compounds were studied by using infrared spectroscopy, scanning electron microscopy and 1H nuclear magnetic resonance characterization techniques. This method allows the possibility of reusing IL, confirming the versatility of the established method. The fraction rich in cellulose and hemicellulose was subjected to acid hydrolysis (0.2 mol/L H2SO4) for 5 h at 140 °C, obtaining a yield of total reducing sugars of approximately 80%, much higher than those obtained in non-pretreated samples.
Application of a Hybrid Optimized BP Network Model to Estimate Water Quality Parameters of Beihai Lake in Beijing
Authors: Yan Jianzhuo , Xu Zongbao , Yu Yongchuan , Xu Hongxia , Gao Kaili
Published: May 2019

Nowadays, freshwater resources are facing numerous crises and pressures, resulting from both artificial and natural process, so it is crucial to predict the water quality for the department of water environment protection. This paper proposes a hybrid optimized algorithm involving a particle swarm optimization (PSO) and genetic algorithm (GA) combined BP neural network that can predict the water quality in time series and has good performance in Beihai Lake in Beijing. The data sets consist of six water quality parameters which include Hydrogen Ion Concentration (pH), Chlorophyll-a (CHLA), Hydrogenated Amine (NH4H), Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), and electrical conductivity (EC). The performance of the model was assessed through the absolute percentage error ( A P E m a x ), the mean absolute percentage error (MAPE), the root mean square error (RMSE), and the coefficient of determination ( R 2 ). Study results show that the model based on PSO and GA to optimize the BP neural network is able to predict the water quality parameters with reasonable accuracy, suggesting that the model is a valuable tool for lake water quality estimation. The results show that the hybrid optimized BP model has a higher prediction capacity and better robustness of water quality parameters compared with the traditional BP neural network, the PSO-optimized BP neural network, and the GA-optimized BP neural network.
Loitering Detection Based on Pedestrian Activity Area Classification
Authors: Huang Tiemei , Han Qing , Min Weidong , Li Xiangpeng , Yu Yunjun , Zhang Yu
Published: May 2019

Loitering detection can help recognize vulnerable people needing attention and potential suspects harmful to public security. The existing loitering detection methods used time or target trajectories as assessment criteria, and only handled some simple loitering circumstances because of complex track. To solve these problems, this paper proposes a loitering detection method based on pedestrian activity area classification. The paper first gave loitering definition from a new perspective using the size of pedestrian activity area. The pedestrian loitering behaviors were divided into three categories. The proposed algorithms dynamically calculate enclosing rectangle, ellipse, and sector of pedestrian activity areas through curve fitting based on trajectory coordinates within given staying time threshold. The loitering is recognized if the pedestrian activity is detected to be constrained in an area within a certain period of time. The algorithm does not need to calculate complex trajectories. The PETS2007 dataset and our own self-collected simulated test videos were tested. The experimental results show that the proposed method accurately detected the pedestrian loitering, not only detected some loitering that the existing methods could not detect, but also distinguishing different types of loitering. The proposed method is effectiveness, robust, and simplified in implementation.
Advancement of Individualized Head-Related Transfer Functions (HRTFs) in Perceiving the Spatialization Cues: Case Study for an Integrated HRTF Individualization Method
Authors: Wang Lei , Zeng Xiangyang , Ma Xiyue
Published: May 2019

Head-related transfer function (HRTF), which varies across individuals at the same direction, has grabbed widespread attention in the field of acoustics and been used in many scenarios. In order to in-depth investigate the performance of individualized HRTFs on perceiving the spatialization cues, this study presents an integrated algorithm to obtain individualized HRTFs, and explores the advancement of such individualized HRTFs in perceiving the spatialization cues through two different binaural experiments. An integrated method for HRTF individualization on the use of Principle Component Analysis (PCA), Multiple Linear Regression (MLR) and Partial Least Square Regression (PLSR) was presented first. The objective evaluation was then made to verify the algorithmic effectiveness of that method. Next, two subjective experiments were conducted to explore the advancement of individualized HRTFs in perceiving the spatialization cues. One was auditory directional discrimination degree based on semantic differential method, in which the azimuth information of sound sources was told to the listeners before listening. The other was auditory localization, in which the azimuth information was not told to the listeners before listening. The corresponding statistical analyses for the subjective experimental results were made. All the experimental results support that individualized HRTFs obtained from the presented method achieve a preferable performance in perceiving the spatialization cues.
Spatial Analysis of Navigation in Virtual Geographic Environments
Authors: Ugwitz Pavel , Juřík Vojtěch , Herman Lukáš , Stachoň Zdeněk , Kubíček Petr , Šašinka Čeněk
Published: May 2019

Human performance and navigation activity in virtual environments can be measured and assessed with the aim to draw specific conclusions about human cognition. This paper presents an original virtual geographic environment (VGE) designed and used for this purpose. The presented research is rooted in an interdisciplinary approach combining knowledge and principles from the fields of psychology, cartography, and information technologies. The VGE was embedded with user logging functionality to provide a basis from which conclusions about human cognitive processes in a VGE could be drawn. The scope of this solution is introduced, described, and discussed under a behavioral measurement framework. An exploratory research design was adopted to demonstrate the environment’s utility in proof-of-concept user testing. Twenty participants were observed in interactive, semi-interactive and non-interactive tasks, their performance and individual differences were analyzed. The behavioral measurements were supplemented by Object-Spatial Imagery and a Verbal Questionnaire to determine the participants’ cognitive styles. In this sample, significant differences in exploration strategies between men and women were detected. Differences between experienced and non-experienced users were also found in their ability to identify spatial relations in virtual scenes. Finally, areas for future research areas and development were pinpointed.
A Microcrack Location Method Based on Nonlinear S0 Mode Lamb Wave and Probability Scan Positioning Imaging Matrix
Authors: Li Yibo , Zhang Shuo , Rui Xiaobo , Ma Chang , Yang Zi
Published: May 2019

Early damage, such as microcrack, occupies most of the fatigue life of materials, and timely detection of early damage and positioning has great engineering and economic value. In this paper, a matrix scanning and positioning imaging method based on a probabilistic algorithm is proposed. Cooperating with the single-mode (S0) lamb wave, the microcrack in the thin plate material can be efficiently positioned. Taking the S0 mode lamb wave as the fundamental wave can effectively reduce the influence of the dispersion effect on the signal analysis. Meanwhile, in order to reduce the noise interference, the signal is reconstructed by empirical mode decomposition (EMD) to achieve the filtering effect. Then, the ABAQUS finite element simulation software is used to compare the positioning results under different locations of microcrack and different arrangements of probe. Finally, the feasibility of the localization algorithm is verified by the RAM-5000 SNAP nonlinear ultrasound system. The experimental results are consistent with the simulation theory, and the microcrack is effectively positioned. This facilitates our timely remedial action or further assessment of the remaining value of the material.
Mechanism of Combustion Noise Influenced by Pilot Injection in PPCI Diesel Engines
Authors: Du Jingtao , Chen Ximing , Liu Long , Liu Dai , Ma Xiuzhen
Published: May 2019

Pilot injection combined with exhaust gas recirculation (EGR) is usually utilized to realize the partially premixed compression ignition (PPCI) mode in diesel engines, which enables the simultaneous decrease of nitrogen oxide and soot emissions to satisfy emission regulations. Moreover, the ignition delay of main injection combustion can also be shortened by pilot injection, and then combustion noise is reduced. Nevertheless, the mechanisms of pilot injection impacts on combustion noise are not completely understood. As such, it is hard to optimize pilot injection parameters to minimize combustion noise. Therefore, experiments were conducted on a four-stroke single-cylinder diesel engine with different pilot injection strategies and 20% EGR as part of an investigation into this relationship. Firstly, the combustion noise was analyzed by cylinder pressure levels (CPLs). Then, the stationary wavelet transforms (SWTs) and stationary wavelet packet transform (SWPT) were employed to decompose in-cylinder pressures at different scales, and thus the combustion noise generated by pilot and main combustion was investigated in both the time and frequency domain. The results show that pilot injection is dominant in the high frequency segment of combustion noise, and main injection has a major impact on combustion noise in the low and mid frequency segment. Finally, the effects of various pilot injection parameters on suppressing combustion noise were analyzed in detail.
Potential of Solar Collectors for Clean Thermal Energy Production in Smart Cities using Nanofluids: Experimental Assessment and Efficiency Improvement
Authors: Sarafraz M. , Tlili Iskander , Abdul Baseer Mohammad , Safaei Mohammad
Published: May 2019

In this article, an experimental study was performed to assess the potential thermal application of a new nanofluid comprising carbon nanoparticles dispersed in acetone inside an evacuated tube solar thermal collector. The effect of various parameters including the circulating volumetric flow of the collector, mass fraction of the nanoparticles, the solar irradiance, the tilt angle and the filling ratio values of the heat pipes on the thermal performance of the solar collector was investigated. It was found that with an increase in the flow rate of the working fluid within the system, the thermal efficiency of the system was improved. Additionally, the highest thermal performance and the highest temperature difference between the inlet and the outlet ports of the collector were achieved for the nanofluid at wt. % = 0.1. The best tilt angle and the filling ratio values of the collector were 30° and 60% and the maximum thermal efficiency of the collector was 91% for a nanofluid at wt. % = 0.1 and flow rate of 3 L/min.
Modeling of the Accidentality Phenomenon in the Construction Industry
Authors: Hoła Bożena , Szóstak Mariusz
Published: May 2019

The aim of the conducted research was to develop a methodology of investigating the accidentality phenomenon in the construction industry, which is considered as a process that is created by a sequence of accidents occurring at discrete periods of time and at various construction sites in terms of their location, construction, and technical equipment. In order to investigate the circumstances of accidents, a methodology developed by the European Statistical Office of the European Union (ESAW) was used during the research. The basic elements of the proposed methodology is the IT database (computer knowledge database (CKD)), which includes information about the circumstances and causes of accidents and also constitutes a repository for the collected data, as well as a graphic and IT model of the accident process in the form of a directed graph. In order to detect the characteristic features of the accidentality phenomenon in the construction industry, a simulation of a sequence that consists of 485 occupational accidents that occurred in 2008–2016 in five Polish voivodeships was carried out. The conducted research and analysis allowed the most common accident scenarios that occur in the construction industry to be identified, as well as the probability of their occurrence and the critical path in the graph that indicates the most accident-causing activities to be determined. The proposed model is important for construction practice. Based on a large set of data on accidents included in the CKD, it is possible to study the impact of the following on the accidentality phenomenon: Technologies used in the construction industry, the types of carried out construction works, and the methods used to organize work and equipment.
Special Issue on “Side Channel Attacks”
Authors: Hong Seokhie
Published: May 2019

Cryptosystems are widely used in a growing number of embedded applications, such as smart cards, smart phones, Internet of Things (IoT) devices, and so on [...]
Optimization of Processing Parameters for Water-Jet-Assisted Laser Etching of Polycrystalline Silicon
Authors: Chen Xuehui , Li Xiang , Wu Chao , Ma Yuping , Zhang Yao , Huang Lei , Liu Wei
Published: May 2019

Liquid-assisted laser technology is used to etch defect-free materials for high-precision electronics and machinery. This study investigates water-jet-assisted laser etching of polysilicon material. The depths and widths of the etched grooves were investigated for different water-jet incident angles and velocities. To select optimal parameters for a composite etching processing, the results of many tests must be compared, and at least one set of good processing parameter combinations must be identified. Herein, the influence of different parameters on the processing results is studied using an orthogonal test method. The results demonstrate that the depths and widths of the processing grooves were nearly identical at water-jet angles of 30°and 60°; however, the 60° incidence conferred a slight advantage over 30° incidence. The section taper, section depth, and surface topography were optimized at a water-jet velocity of 24-m/s, 1.1-ms laser pulse width, 40-Hz frequency, and 180-A current. Under these conditions, the section taper and groove depth were 1.2° and 1.88 mm, respectively. The groove surfaces exhibited no splitting, slagging, or other defects, and no recast layers were visible.
A Smart System for Text-Lifelog Generation from Wearable Cameras in Smart Environment Using Concept-Augmented Image Captioning with Modified Beam Search Strategy
Authors: Vo-Ho Viet-Khoa , Luong Quoc-An , Nguyen Duy-Tam , Tran Mai-Khiem , Tran Minh-Triet
Published: May 2019

During a lifetime, a person can have many wonderful and memorable moments that he/she wants to keep. With the development of technology, people now can store a massive amount of lifelog information via images, videos or texts. Inspired by this, we develop a system to automatically generate caption from lifelog pictures taken from wearable cameras. Following up on our previous method introduced at the SoICT 2018 conference, we propose two improvements in our captioning method. We trained and tested the model on the baseline MSCOCO datasets and evaluated on different metrics. The results show better performance compared to our previous model and to some other image captioning methods. Our system also shows effectiveness in retrieving relevant data from captions and achieve high rank in ImageCLEF 2018 retrieval challenge.
Self-Disclosure to an IoT Conversational Agent: Effects of Space and User Context on Users’ Willingness to Self-Disclose Personal Information
Authors: Li Ziyang , Rau Pei-Luen Patrick , Huang Dinglong
Published: May 2019

In the era of the Internet of Things (IoT), IoT conversational agents (IoT-CAs) have become the gateways for smart spaces. Users will inevitably self-disclose some types of personal information while interacting with IoT-CAs. In this study, users’ willingness to disclose different types of information to IoT-CAs in two smart spaces (living space and workspace) and two user contexts (one user or two users) was investigated. One living space and one workspace were built for users to experience interactions with IoT-CAs. Subsequently, users’ willingness to self-disclose six types of personal information was measured. Two experiments were separately conducted for a single user (N = 36) and two users (N = 48). The results indicated that users were most willing to disclose information about their tastes and interests and least willing to disclose money information. Users in the living space were willing to disclose more information than those in the workspace, which was mediated by users’ expectations for the reciprocal services of IoT-CAs rather than the awareness of other persons or external factors. Participants had a high private self-awareness in the living space and workspace; their attention was focused on themselves rather than on external factors in smart spaces.
Improving the Accuracy of Fault Frequency by Means of Local Mean Decomposition and Ratio Correction Method for Rolling Bearing Failure
Authors: Duan Yongqiang , Wang Chengdong , Chen Yong , Liu Peisen
Published: May 2019

The fault frequencies are as they are and cannot be improved. One can only improve its estimation quality. This paper proposes a fault diagnosis method by combining local mean decomposition (LMD) and the ratio correction method to process the short-time signals. Firstly, the vibration signal of rolling bearing is decomposed into a series of product functions (PFs) by LMD. The PF, which contains the richest fault information, is selected to perform envelope spectrum analysis by the Hilbert transform (HT). Secondly, the Hilbert envelope spectrum of the selected PF is corrected with the ratio correction method. Finally, higher precision fault frequencies are extracted from the corrected Hilbert envelope spectrum, and then the fault location is accurately determined. The proposed method of this paper can be used in online real-time monitoring technology of rolling bearing failure.
A Hybrid Method for Remaining Useful Life Estimation of Lithium-Ion Battery with Regeneration Phenomena
Authors: Zhao Lin , Wang Yipeng , Cheng Jianhua
Published: May 2019

The lithium-ion battery has become the primary energy source of many electronic devices. Accurately forecasting the remaining useful life (RUL) of a battery plays an essential role in ensuring reliable operatioin of an electronic system. This paper investigates the lithium-ion battery RUL prediction problem with capacity regeneration phenomena. We aim to reduce the accumulation of the prediction error by integrating different capacity degradation models and thereby improve the prediction accuracy of the long-term RUL. To describe the degradation process more accurately, we decoupled the degradation process into two types: capacity regeneration and normal degradation. Then, we modelled two kinds of degradation processes separately. In the prediction phase, we predicted the battery state of health (SOH) by using the relevance vector machine (RVM) and the gray model (GM) alternately, updated the training dataset according to the prediction results, and then updated the RVM and GM. The RVM and GM correct each other’s prediction results constantly, which reduces the cumulative error of prediction and improves the prediction accuracy of the battery SOH. Experimental results with the National Aeronautics and Space Administration (NASA) battery dataset demonstrated that the proposed method can accurately establish the degradation model and achieve better performance for the RUL estimation as compared with the single RVM or GM methods.
A Numerical Solution for Broadband PLC Splitter with Variable Splitting Ratio Based on Asymmetric Three Waveguide Structures
Authors: Wang Hseng-Tsong , Chen Chi-Feng , Chi Sien
Published: May 2019

A numerical solution for the broadband planar-lightwave-circuit (PLC) splitter with a variable splitting ratio based on asymmetric three waveguides weighted by the Blackman weighting function is designed for passive optical network applications with wavelengths between 1.53 and 1.57 µm. The performance of the proposed splitter is verified using the beam propagation method (BPM). It was found that a polynomial function of the splitting ratios accompanying a geometrical shift can be derived from the proposed splitter. The splitting ratio can be changed from 50:50 to 90:10 with this geometrical shift. The excess loss, crosstalk, polarization dependent loss, and splitting ratio variations against wavelength of the proposed splitter with wavelengths between 1.53 and 1.57 µm are better than 0.139 dB, −22.75 dB, 0.006 dB, and 0.335%, respectively. Obviously, the proposed splitter with variable splitting ratio retains the advantages of the symmetric design, such as low excess loss, low crosstalk, polarization insensitivity, broadband, and wavelength insensitivity.
Theoretical Framework for Characterizing Strain-Dependent Dynamic Soil Properties
Authors: Chong Song-Hun
Published: May 2019

This paper proposes a theoretical framework for the characterization of the strain-dependent dynamic properties of soils. The analysis begins with an analytical constitutive model for soils under steady-state cyclic loading. The model describes the dominant soil characteristics, i.e., the hysteresis and nonlinearity with an intrinsic material property α, which physically represents the degree of the hysteresis nonlinearity in a medium. Explicit formulas for the backbone curve, tangent shear modulus, secant shear modulus, and damping ratio as a function of shear strain are derived directly from the constitutive model. A procedure is then developed to determine the parameter α in which the derived damping ratio equation is fitted to damping ratio data measured from the resonant column test (RCT). Clay and sand under three different levels of confinement stress are considered in the numerical evaluation. The capability of the proposed theoretical framework in predicting strain-dependent soil properties and responses is demonstrated.