bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Velocity Second Slip and Inclined Magnetic Field on Peristaltic Flow Coating with Jeffrey Fluid in Tapered Channel
Authors: Saleem Najma , Akram Safia , Afzal Farkhanda , H. Aly Emad , Hussain Anwar
Published: January 2020

The peristaltic flow of velocity second slip boundary conditions and inclined magnetic field of Jeffrey fluid by means of heat and mass transfer in asymmetric channel was inspected in the present study. Leading equations described the existing flow were then simplified under lubrication approach. Therefore, exact solutions of stream function, concentration and temperature were deduced. Further, the numerical solutions of pressure rise and pressure gradient were computed using Mathematica software. Furthermore, the effect of the second slip parameter was argued via graphs. It has been depicted that this kind of slip is mandatory and very imperative to foresee the physical model. On the other hand, false results will be obtained.
Nonlinear Dynamic Characteristic Analysis of a Coated Gear Transmission System
Authors: Xiao Yangyi , Fu Liyang , Luo Jing , Shi Wankai , Kang Minglin
Published: January 2020

Coatings can significantly improve the load-carrying performance of a gear surface, but how they affect the vibration characteristic of the system is an urgent issue to be solved. Taking into account the nonlinear factors like the variable mesh stiffness, friction, backlash, and transmission error, a six-degree-of-freedom spur gear transmission system with coatings is presented. Meanwhile, the finite element method is applied to acquire the time-varying mesh stiffness of the coated gear pair in the engagement process. With the support of the time-history curve, phase curve, Poincare map, and fast Fourier transform spectrum, the dynamic characteristics and the effects of the coating elastic modulus on vibration behaviors of a gear transmission system are minutely dissected by using a numerical integration approach. Numerical cases illustrate that the dynamic characteristic of a gear transmission system tends toward a one-period state under the given operating condition. They also indicate that, compared with softer coatings, stiffer ones can properly enhance the transmission performance of the coated gear pair. Numerical results are also compared with previous studies, and can establish a theoretical basis for dynamic design and vibration control of the coated gear transmission system.
Mechanical and Structural Properties of Nanocomposite CrAlSiN–AlSiN Coating with Periodically Modulated Composition
Authors: Kolaklieva Lilyana , Kakanakov Roumen , Stefanov Plamen , Kovacheva Daniela , Atanasova Genoveva , Russev Stoyan , Chitanov Vasiliy , Cholakova Tetyana , Bahchedjiev Christo
Published: January 2020

A nanocomposite CrAlSiN–AlSiN coating with periodically modulated composition was developed and investigated regarding the effect of the composition and structure on the mechanical properties. The modulation was performed by variation of the pressure, cathode current and bias voltage during deposition. The structure and composition of the coating were investigated by X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS) analyses. The coating had a nanocomposite structure consisting of (CrAl)N and (AlSi)N nanograins embedded in a Si3N4 matrix. The EDS analysis of the cross-section revealed that the period composition had changed from Cr051Al0.41Si0.08N to Al0.82Cr0.04Si0.14N. It was shown that the elastic modulus could be adjusted by composition modulation. The coating hardness of 54 GPa was obtained by nanoindentation. The modulated CrAlSiN–AlSiN coating exhibited improved elastic strain to failure (H/E* = 0.11, H—nanohardness, E*—the effective elastic modulus), excellent resistance to plastic deformation (H3/E*2 = 0.72), and elastic recovery of 70%, which suggested improved toughness.
A Practical Method for Assessing Lip Compression Strengthening in Healthy Adults
Authors: Abe Takashi , Bell Zachary W. , Wong Vickie , Spitz Robert W. , Viana Ricardo B. , Yamada Yujiro , Chatakondi Raksha N. , Loenneke Jeremy P.
Published: January 2020

There is no practical and accessible assessment method to evaluate lip muscle compression strength. The purpose of this study was to examine the relationship between the standard method (i.e., Iowa Oral Performance Instrument) and a practical method in healthy adults. In order to achieve our research purpose, ninety-eight healthy adults (18–40 years) completed lip compression strength measurements (standard method) and lip grasping performance tests using a standard recyclable plastic water bottle (practical method). In the overall sample, the mean and standard deviation for standard method and practical method was 26.7 (7.0) kPa and 255 (119) g, respectively. For the overall sample (n = 98), there was a positive relationship between the two strength tasks [r = 0.56 (0.41, 0.68)]. When separated by sex, positive correlations were observed for men and women with no differences between the observed correlations [difference of 0.06 (−0.2646, 0.3917)]. This result indicates that those individuals who are strong in the standard task will often be strong in the practical task. Future research is needed to determine how well changes in each test track with each other in response to a lip strength training program.
Three Multi-Components Reaction: Synthesis and X-Ray Single-Crystal of Hydroacridinone-Based Hydrazino-S-Triazine Derivative as a New Class of Urease Inhibitor
Authors: Barakat Assem , Soliman Saied M. , El-Faham Ayman , Ali M. , Al-Majid Abdullah Mohammed , Yousuf Sammer , Choudhary M. Iqbal
Published: January 2020

The one-pot fashion of three multi-component reaction provides the desired hydroacridinone-based hydrazino-s-triazine scaffold 4. Compound 4 was crystallized in an orthorhombic crystal system and Pbca space group with a = 11.6271(2) Å, b = 18.2018(4) Å, c = 32.4721(6) Å, and α = β = γ = 90° with one formula unit per asymmetric unit and eight molecules per unit cell. Additionally, structural features, Hirshfeld surfaces, and DFT studies were also investigated. Its packing in the crystal is controlled by H…H (63.4%), O…H (12.7%), Cl…H (7.2%), N…H (4.7%), and C…H (10.2%) contacts, where the O…H and Cl…H contacts were found the strongest. In vitro urease inhibition evaluation showed that the hydroacridinone-based hydrazino-s-triazine is more active (IC50 = 17.9 ± 0.47 µM) than the standard acetohydroxamic acid (IC50 = 20.3 ± 0.43 µM).
Organoelement Compounds Crystallized In Situ: Weak Intermolecular Interactions and Lattice Energies
Authors: Volodin Alexander D. , Korlyukov Alexander A. , Smol’yakov Alexander F.
Published: January 2020

The in situ crystallization is the most suitable way to obtain a crystal of a low-melting-point compound to determine its structure via X-Ray diffraction. Herein, the intermolecular interactions and some crystal properties of low-melting-point organoelement compounds (lattice energies, melting points, etc.) are discussed. The discussed structures were divided into two groups: organoelement compounds of groups 13–16 and organofluorine compounds with other halogen atoms (Cl, Br, I). The most of intermolecular interactions in the first group are represented by weak hydrogen bonds and H···H interactions. The crystal packing of the second group of compounds is stabilized by various interactions between halogen atoms in conjunction with hydrogen bonding and stacking interactions. The data on intermolecular interactions from the analysis of crystal packing allowed us to obtain correlations between lattice energies and Hirshfeld molecular surface areas, molecular volumes, and melting points.
Quasi-Transient Calculation of Czochralski Growth of Ge Crystals Using the Software Elmer
Authors: Miller Wolfram , Abrosimov Nikolay , Fischer Jörg , Gybin Alexander , Juda Uta , Kayser Stefan , Janicskó-Csáthy Jószef
Published: January 2020

A numerical scheme was developed to compute the thermal and stress fields of the Czochralski process in a quasi-time dependent mode. The growth velocity was computed from the geometrical changes in melt and crystal due to pulling for every stage, for which the thermal and stress fields were computed by using the open source software Elmer. The method was applied to the Czochralski growth of Ge crystals by inductive heating. From a series of growth experiments, we chose one as a reference to check the validity of the scheme with respect to this Czochralski process. A good agreement both for the shapes of the melt/crystal interface at various time steps and the change in power consumption with process time was observed.
Topological Equivalence of the Phase Diagrams of Molybdenum and Tungsten
Authors: Baty Samuel , Burakovsky Leonid , Preston Dean
Published: January 2020

We demonstrate the topological equivalence of the phase diagrams of molybdenum (Mo) and tungsten (W), Group 6B partners in the periodic table. The phase digram of Mo to 800 GPa from our earlier work is now extended to 2000 GPa. The phase diagram of W to 2500 GPa is obtained using a comprehensive ab initio approach that includes (i) the calculation of the

T
=
0

free energies (enthalpies) of different solid structures, (ii) the quantum molecular dynamics simulation of the melting curves of different solid structures, (iii) the derivation of the analytic form for the solid–solid phase transition boundary, and (iv) the simulations of the solidification of liquid W into the final solid states on both sides of the solid–solid phase transition boundary in order to confirm the corresponding analytic form. For both Mo and W, there are two solid structures confirmed to be present on their phase diagrams, the ambient body-centered cubic (bcc) and the high-pressure double hexagonal close-packed (dhcp), such that at

T
=
0

the bcc–dhcp transition occurs at 660 GPa in Mo and 1060 GPa in W. In either case, the transition boundary has a positive slope

d
T
/
d
P
.
Diagnosis of Tinnitus Due to Auditory Radiation Injury Following Whiplash Injury: A Case Study
Authors: Lee Sung Jun , Bae Chang Hoon , Seo Jeong Pyo , Jang Sung Ho
Published: January 2020

We report on a patient with tinnitus who showed injury of auditory radiation following whiplash injury, demonstrated by diffusion tensor tractography (DTT). A 48-year-old male patient suffered from a car crash resulting in flexion-hyperextension injury of his head after being hit from behind by a moving car while waiting at a signal while driving a car. Three days after the car crash, he began to feel tinnitus in both ears and his tinnitus became aggravated with the passage of time. No specific lesion was observed on a conventional brain MRI performed two weeks after the car crash. Although he visited several hospitals, the precise cause of his tinnitus was not detected. Two years after the car crash, he underwent evaluation for his tinnitus at the ear, nose and throat department of a university hospital. The pure tone audiometry was evaluated in a sound-proof room to screen his hearing status for the frequencies of 250–8000 Hz and no specific abnormality was detected. Although he was also tested for speech audiometry, there was also no specific abnormality. In order to assess his tinnitus, a tinnitogram was conducted to evaluate the frequency content and the loudness. His tinnitus was characterized at an intensity of 40 dB and a frequency of 4000 Hz. However, no abnormality was observed in either ear on physical examination. On DTT, the auditory radiation showed severe narrowing and tearing in both hemispheres. To summarize, neural injury of the auditory radiation was demonstrated in a patient with tinnitus following whiplash injury, using DTT.
The Effects of 3% Diquafosol Sodium Eye Drops on Tear Function and the Ocular Surface of Cu, Zn-Superoxide Dismutase-1 (Sod1) Knockout Mice Treated with Antiglaucoma Eye Medications
Authors: Yagi-Yaguchi Yukari , Kojima Takashi , Higa Kazunari , Dogru Murat , Ibrahim Osama MA. , Shimizu Takahiko , Tsubota Kazuo , Shimazaki Jun
Published: January 2020

Anti-glaucoma eye drop treatment often induces dry eyes and can lead to poor medication adherence. This study aimed to investigate the effects of 3% diquafosol sodium eye drops on tear function and the ocular surface epithelium in Sod1−/− mice after treatment with anti-glaucoma eye drops. The mice were divided into four groups: group 1, control group; group 2, anti-glaucoma eye drop; group 3, anti-glaucoma eye drops followed by a secretagogue eye drop (3% diquafosol); and group 4, simultaneous anti-glaucoma and secretagogue eye drop. Mice underwent assessments of tear quantity, tear film breakup time, and vital staining score. Mice in groups 3 and 4 showed significantly better tear stability and lower corneal staining scores than mice in group 2 after eye drop instillations (p < 0.05). Mice in group 4 showed significantly better tear stability, lower corneal staining scores, and higher goblet cell densities than those in group 1 after eye drop instillations (p < 0.05). The conjunctival epithelium showed stratification and abundance of Muc5AC-positive goblet cells in group 4, whereas thinning with desquamation was observed with a few goblet cells in group 2. Thus, simultaneous administration of 3% diquafosol sodium eye drops with topical anti-glaucoma drops showed favorable effects on tear stability and the corneal epithelium against the ocular surface toxicity inflicted by the anti-glaucoma eye drops.
Deep and Densely Connected Networks for Classification of Diabetic Retinopathy
Authors: Riaz Hamza , Park Jisu , Choi Hojong , Kim Hyunchul , Kim Jungsuk
Published: January 2020

Diabetes has recently emerged as a worldwide problem, and diabetic retinopathy is an abnormal state associated with the human retina. Due to the increase in daily screen-related activities of modern human beings, diabetic retinopathy is more prevalent among adults, leading to minor and major blindness. Doctors and clinicians are unable to perform early diagnoses due to the large number of patients. To solve this problem, this study introduces a classification model for retinal images that distinguishes between the various stages of diabetic retinopathy. This work involves deploying deep and densely connected networks for retinal image analysis with training from scratch. Dense connections between the convolutional layers of the network are an essential factor to enhance accuracy owing to the deeper supervision between layers. Another factor is the growth rate that further assists our model in learning more sophisticated feature maps regarding retinal images from every stage of the network. We compute the area under the curve, sensitivity, and specificity, particularly for messidor-2 and EyePACS. Compared to existing approaches, our method achieved better results, with an approximate rise rate of 0.01, 0.03, and 0.01, respectively. Therefore, computer-aided programs can help in diagnostic centers as automated detection systems.
Impact of Fixed Orthodontic Appliance and Clear Aligners on the Periodontal Health: A Prospective Clinical Study
Authors: Pango Madariaga Ada Carolina , Bucci Rosaria , Rongo Roberto , Simeon Vittorio , D’Antò Vincenzo , Valletta Rosa
Published: January 2020

This study aimed to evaluate the periodontal health of orthodontic patients with supportive periodontal therapy in a 3 month follow-up. The sample comprised 20 patients (mean age 20.6 ± 8.1 years) in treatment with multibracket fixed appliances (fixed group—FG) and 20 patients (mean age 34.7 ± 12.5 years) in treatment with clear aligners (clear aligners group—CAG). At baseline (T0) and after 3 months (T1), probing depth (PD), plaque index (PI), bleeding on probing (BOP), and gingival recession (REC) were measured. Patients were trained to perform an individualized tooth brushing technique, and every 2 weeks they were re-called to reinforce the oral hygiene instructions. The intra-group comparisons (T1 vs. T0) were calculated with the Wilcoxon signed-rank test, while a linear regression model was used for the inter-group comparisons (FG vs. CAG). The significance level was set at p < 0.05. Statistically significant decrease in both groups was found for PD (FG: Δ, −9.2 inter-quartile range (IQR), −22.5, −5.5; CAG: Δ, −12.6 IQR, −25.4, −4.8), BOP (FG: Δ, −53.5 IQR, −70.5, −37; CAG: Δ, −37.5 IQR, −54.5, −23), and PI (FG: Δ, −17.5 IQR, −62.5, 14.5; CAG: Δ, −24 IQR, −49.5, −5). The result of the linear regression models suggested that the type of appliance did not have any effects on the improvement of periodontal variables. Therefore, patients undergoing orthodontic treatment with fixed appliances and clear aligners did not show differences in gingival health when followed by a dental hygienist.
Eco-Innovation Activities in the Czech Economy 2008–2014: Impact of the Eco-Innovative Approach to the Profit Stream and Differences in Urban and Rural Enterprises
Authors: Vokoun Marek , Jílková Jiřina
Published: January 2020

The environmental benefits from the eco-innovation activities of enterprises have the nature of reduced material or water use per unit of output, less pollution and waste, better CO2 ‘footprint’ in production and subsequent business processes. The socioeconomic impacts are associated with circular economy benefits like reduced energy use, decreased pollution and waste, and well-organized recycling possibilities of the product after use. The goal of this paper is to evaluate this innovative approach in the Czech economy. The hypotheses are aimed at the localization of enterprises, appropriability, and characteristics of enterprises that introduce eco-innovations to markets. The dataset is provided by the Czech Statistical Office and contains observations about the innovation activities of firms. Eco-innovation was surveyed in 2008 and 2014. This paper utilizes the estimation principles of CDM (Crépon, Duguet, and Mairesse) method at the firm level. The results suggest that rural–urban separation has no impact on the financial R&D intensity but urban enterprises have a higher probability to engage in innovation activities. The probability to introduce new-to-the-market innovations and eco-innovations is not dependent on localization. High-tech and knowledge-intensive industries have a lower probability to introduce eco-innovations to the market. The change in localization of enterprises to rural areas contributed to the higher sales form innovated goods and services. Higher appropriability was also observed in product eco-innovators. This paper offers a synthesis of factors that stimulate eco-innovation and shows that eco-innovation is a viable and sustainable innovative approach for rural and urban enterprises and identifies directions for future research.
Taking Universal Design Back to Its Roots: Perspectives on Accessibility and Identity in Undergraduate Mathematics
Authors: Nieminen Juuso , Pesonen Henri Valtteri
Published: January 2020

Universal Design has been promoted to address the diversity of learners in higher education. However, rarely have Universal Design implementations been evaluated by listening to the voices of disabled students. For this study, we investigated the perceptions of three disabled students who took part in an undergraduate mathematics course designed with the principles of Universal Design for Learning and Assessment. The study consists of two parts. First, we observed the experiences students had in relation to the accessibility of the course design. The second part consisted of a further analysis of the students identifying processes to understand how they talked about their learning disabilities during the course. Our results highlight many opportunities and challenges that the course offered to the students, whilst also raising concerns about how the students excluded themselves from their student cohort in their identifying narratives. Based on our results, we argue that Universal Design should be returned to its roots by connecting it with the social model of disability. We call for future research to learn from our mistakes and consider the identifying processes of the students while designing, and hopefully co-designing, inclusive learning environments in mathematics.
The Implementation of an Ethical Education Curriculum in Secondary Schools in Ireland
Authors: Bourke Maria , Kinsella William , Prendeville Paula
Published: January 2020

The paper investigates teachers’ and principals’ experiences of implementing a pilot of an ethical education (EE) curriculum to a senior cycle programme in Educate Together secondary schools in Ireland. The development of this curriculum was informed by the Integrative Ethical Education Model (Lapsley and Narvaez, 2004). Thirteen teachers and two school principals were interviewed about their experiences of this curriculum and its impact on school culture and organisation. An implementation science approach informed a thematic analysis of transcripts that interrogated the perspectives of participants, and revealed the systemic factors that included barriers to, and facilitators of, EE curriculum implementation. Interviews were analysed inductively, by exploring participants’ experiences, and deductively, using Narvaez’s framework of ethical skills. Results were presented within the domains of school setting, wider school setting, curriculum characteristics and teacher characteristics, reflecting an implementation science approach. Findings suggest that this curriculum nurtured a positive school climate where students identified as having a greater sense of school belonging as a result of access to this curriculum.
An Efficient Document Skew Detection Method Using Probability Model and Q Test
Authors: Huang Kai , Chen Zixuan , Yu Min , Yan Xiaolang , Yin Aiguo
Published: January 2020

Document skew detection is one of the key technologies in most of the document analysis systems. However, existing skew detection methods either have low accuracy or require a large amount of computation. To achieve a good tradeoff between efficiency and performance, we propose a novel skew detection approach based on bounding boxes, probability model, and Dixon’s Q test. Firstly, bounding boxes are used to pick out the eligible connected components (ECC). Then, we calculate the slopes of the skew document with the probability model. Finally, we find the optimal result with Dixon’s Q test and projection profile method. Moreover, the proposed method can detect the skew angle in a wider range. The experimental results show that our skew detection algorithm can achieve high speed and accuracy simultaneously compared with existing algorithms.
A Traceable and Privacy-Preserving Authentication for UAV Communication Control System
Authors: Chen Chin-Ling , Deng Yong-Yuan , Weng Wei , Chen Chi-Hua , Chiu Yi-Jui , Wu Chih-Ming
Published: January 2020

In recent years, the concept of the Internet of Things has been introduced. Information, communication, and network technology can be integrated, so that the unmanned aerial vehicle (UAV) from consumer leisure and entertainment toys can be utilized in high value commercial, agricultural, and defense field applications, and become a killer product. In this paper, a traceable and privacy-preserving authentication is proposed to integrate the elliptic curve cryptography (ECC), digital signature, hash function, and other cryptography mechanisms for UAV application. For sensitive areas, players must obtain flight approval from the ground control station before they can control the UAV in these areas. The traditional cryptography services such as integrity, confidentiality, anonymity, availability, privacy, non-repudiation, defense against DoS (Denial-of-Service) attack, and spoofing attack can be ensured. The feasibility of mutual authentication was proved by BAN logic. In addition, the computation cost and the communication cost of the proposed scheme were analyzed. The proposed scheme provides a novel application field.
An Algorithm for Accurate and Robust Indoor Localization Based on Nonlinear Programming
Authors: Monica Stefania , Bergenti Federico
Published: January 2020

The study of techniques to estimate the position of mobile devices with a high level of accuracy and robustness is essential to provide advanced location based services in indoor environments. An algorithm to enable mobile devices to estimate their positions in known indoor environments is proposed in this paper under the assumption that fixed anchor nodes are available at known locations. The proposed algorithm is specifically designed to be executed on the mobile device whose position is under investigation, and it allows the device to estimate its position within the environment by actively measuring distance estimates from the anchor nodes. In order to reduce the impact of the errors caused by the arrangement of the anchor nodes in the environment, the proposed algorithm first transforms the localization problem into an optimization problem, and then, it solves the derived optimization problem using techniques inspired by nonlinear programming. Experimental results obtained using ultra-wide band signaling are presented to assess the performance of the algorithm and to compare it with reference alternatives. The presented experimental results confirm that the proposed algorithm provides an increased level of accuracy and robustness with respect to two reference alternatives, regardless of the position of the anchor nodes.
Development of a Prototype for Monitoring Photovoltaic Self-Consumption Systems
Authors: Rus-Casas Catalina , Jiménez-Castillo Gabino , Aguilar-Peña Juan Domingo , Fernández-Carrasco Juan Ignacio , Muñoz-Rodríguez Francisco José
Published: January 2020

Currently, the increasing energy consumption around the world and the environmental impact resulting from the use of fossil fuel-based energy have promoted the use of renewable energy sources such as photovoltaic solar energy. The main characteristic of this type of energy is its unpredictability, as it depends on meteorological conditions. In this sense, monitoring the power generation of photovoltaic systems (PVS) in order to analyze their performance is becoming crucial. The purpose of this paper is to design a monitoring system for a residential photovoltaic self-consumption system which employs an Internet of Things (IoT) platform to estimate the photovoltaic power generation according to solar radiation and temperature. The architecture of the developed prototype will be described and the benefits of providing the use of IoT for monitoring will be highlighted, since all data collected by the data acquisition system (DAS) may be stored in the Cloud. The comparison of the results with those of other monitoring systems was very positive, with an uncertainty that complies with the IEC61724 standard.
On Car-Sharing Usage Prediction with Open Socio-Demographic Data
Authors: Cocca Michele , Teixeira Douglas , Vassio Luca , Mellia Marco , Almeida Jussara M. , Couto da Silva Ana Paula
Published: January 2020

Free-Floating Car-Sharing (FFCS) services are a flexible alternative to car ownership. These transportation services show highly dynamic usage both over different hours of the day, and across different city areas. In this work, we study the problem of predicting FFCS demand patterns—a problem of great importance to the adequate provisioning of the service. We tackle both the prediction of the demand (i) over time and (ii) over space. We rely on months of real FFCS rides in Vancouver, which constitute our ground truth. We enrich this data with detailed socio-demographic information obtained from large open-data repositories to predict usage patterns. Our aim is to offer a thorough comparison of several machine-learning algorithms in terms of accuracy and ease of training, and to assess the effectiveness of current state-of-the-art approaches to address the prediction problem. Our results show that it is possible to predict the future usage with relative errors down to 10%, while the spatial prediction can be estimated with relative errors of about 40%. Our study also uncovers the socio-demographic features that most strongly correlate with FFCS usage, providing interesting insights for providers interested in offering services in new regions.
An Improved All-Digital Background Calibration Technique for Channel Mismatches in High Speed Time-Interleaved Analog-to-Digital Converters
Authors: Ta Van-Thanh , Hoang Van-Phuc , Pham Van-Phu , Pham Cong-Kha
Published: January 2020

The time-interleaved analog-to-digital converters (TIADCs), performance is seriously affected by channel mismatches, especially for the applications in the next-generation communication systems. This work presents an improved all-digital background calibration technique for TIADCs by combining the Hadamard transform for calibrating gain and timing mismatches and averaging for offset mismatch cancellation. The numerical simulation results show that the proposed calibration technique completely suppresses the spurious images due to the channel mismatches at the output spectrum, which increases the spurious-free dynamic range (SFDR) and signal-to-noise and distortion ratio (SNDR) by 74 dB and 43.7 dB, respectively. Furthermore, the hardware co-simulation on the field programmable gate array (FPGA) platform is performed to confirm the effectiveness of the proposed calibration technique. The simulation and experimental results clarify the improvement of the proposed calibration technique in the TIADC’s performance.
Common Mode Voltage Elimination for Quasi-Switch Boost T-Type Inverter Based on SVM Technique
Authors: Do Duc-Tri , Nguyen Minh-Khai , Ngo Van-Thuyen , Quach Thanh-Hai , Tran Vinh-Thanh
Published: January 2020

In this paper, the effect of common-mode voltage generated in the three-level quasi-switched boost T-type inverter is minimized by applying the proposed space-vector modulation technique, which uses only medium vectors and zero vector to synthesize the reference vector. The switching sequence is selected smoothly for inserting the shoot-through state for the inverter branch. The shoot-through vector is added within the zero vector in order to not affect the active vectors as well as the output voltage. In addition, the shoot-through control signal of active switches of the impedance network is generated to ensure that its phase is shifted 90 degrees compared to shoot through the signal of the inverter leg, which provides an improvement in reducing the inductor current ripple and enhancing the voltage gain. The effectiveness of the proposed method is verified through simulation and experimental results. In addition, the superiority of the proposed scheme is demonstrated by comparing it to the conventional pulse-width modulation technique.
Experimental Frequency Tuning Methodology of a Cantilever Piezoelectric Harvester Validated in a Multimodal Transportation
Authors: Del-Rio-Ruiz Ruben , Echevarria Juan Jose , Eguiluz Xabier , Lopez-Garde Juan-Manuel , Legarda Jon
Published: January 2020

Piezoelectric energy harvesting is a promising technology that increases the autonomy of low power IoT devices in scenarios that are subjected to mechanical vibrations. This work shows the potential of this technology to power IoT devices with the energy that is harvested from vibrations occurred during air and road transportation. Adjusting the natural resonance frequency of the piezoelectric generator (PEG) to the mechanical acceleration frequency that has the highest power spectral density is key to increase the harvested energy. Therefore, in this work a commercial PEG is tuned to the best spectrogram frequency of a real vibration signal following a two-phase tuning process. The harvested power generated by the PEG has been validated in real scenarios, providing 2.4 μ Wh during flight (take-off, cruise flight, and landing), 11.3 μ Wh during truck transportation in urban areas, and 4.8 μ Wh during intercity transportation. The PEG has been embedded in an ultra-low power IoT device to validate how much this harvested energy can increase the autonomy in a real scenario that is subjected to similar vibrations. An NFC temperature data logger is developed for perishable products that are transported by air and road transports. The energy harvested by the PEG tuned with the methodology proposed in this work has increased the autonomy of the data logger 16.7% during a real use case of 30 h, which validates the potential of the piezoelectric energy harvesting technology to increase the autonomy of future low power IoT devices used in scenarios with aperiodic vibrations.
EV Charging Behavior Analysis Using Hybrid Intelligence for 5G Smart Grid
Authors: Shen Yi , Fang Wei , Ye Feng , Kadoch Michel
Published: January 2020

With the development of the Internet of Things (IoT) and the widespread use of electric vehicles (EV), vehicle-to-grid (V2G) has sparked considerable discussion as an energy-management technology. Due to the inherently high maneuverability of EVs, V2G systems must provide on-demand service for EVs. Therefore, in this work, we propose a hybrid computing architecture based on fog and cloud with applications in 5G-based V2G networks. This architecture allows the bi-directional flow of power and information between schedulable EVs and smart grids (SGs) to improve the quality of service and cost-effectiveness of energy service providers. However, it is very important to select an EV suitable for scheduling. In order to improve the efficiency of scheduling, we first need to determine define categories of target EV users. We found that grouping on the basis of EV charging behavior is one effective method to identify target EVs. Therefore, we propose a hybrid artificial intelligence classification method based on the charging behavior profile of EVs. Through this classification method, target EVs can be accurately identified. The results of cross-validation experiments and performance evaluations suggest that this method is effective.
Development of a High-Performance, FPGA-Based Virtual Anemometer for Model-Based MPPT of Wind Generators
Authors: La Tona Giuseppe , Luna Massimiliano , Di Piazza Maria Carmela , Pucci Marcello , Accetta Angelo
Published: January 2020

Model-based maximum power point tracking (MPPT) of wind generators (WGs) eliminates dead times and increases energy yield with respect to iterative MPPT techniques. However, it requires the measurement of wind speed. Under this premise, this paper describes the implementation of a high-performance virtual anemometer on a field programmable gate array (FPGA) platform. Said anemometer is based on a growing neural gas artificial neural network that learns and inverts the mechanical characteristics of the wind turbine, estimating wind speed. The use of this device in place of a conventional anemometer to perform model-based MPPT of WGs leads to higher reliability, reduced volume/weight, and lower cost. The device was conceived as a coprocessor with a slave serial peripheral interface (SPI) to communicate with the main microprocessor/digital signal processor (DSP), on which the control system of the WG was implemented. The best compromise between resource occupation and speed was achieved through suitable hardware optimizations. The resulting design is able to exchange data up to a 100 kHz rate; thus, it is suitable for high-performance control of WGs. The device was implemented on a low-cost FPGA, and its validation was performed using input profiles that were experimentally acquired during the operation of two different WGs.
Development of a Compact, IoT-Enabled Electronic Nose for Breath Analysis
Authors: Tiele Akira , Wicaksono Alfian , Ayyala Sai Kiran , Covington James A.
Published: January 2020

In this paper, we report on an in-house developed electronic nose (E-nose) for use with breath analysis. The unit consists of an array of 10 micro-electro-mechanical systems (MEMS) metal oxide (MOX) gas sensors produced by seven manufacturers. Breath sampling of end-tidal breath is achieved using a heated sample tube, capable of monitoring sampling-related parameters, such as carbon dioxide (CO2), humidity, and temperature. A simple mobile app was developed to receive real-time data from the device, using Wi-Fi communication. The system has been tested using chemical standards and exhaled breath samples from healthy volunteers, before and after taking a peppermint capsule. Results from chemical testing indicate that we can separate chemical standards (acetone, isopropanol and 1-propanol) and different concentrations of isobutylene. The analysis of exhaled breath samples demonstrate that we can distinguish between pre- and post-consumption of peppermint capsules; area under the curve (AUC): 0.81, sensitivity: 0.83 (0.59–0.96), specificity: 0.72 (0.47–0.90), p-value: <0.001. The functionality of the developed device has been demonstrated with the testing of chemical standards and a simplified breath study using peppermint capsules. It is our intention to deploy this system in a UK hospital in an upcoming breath research study.
Face–Iris Multimodal Biometric Identification System
Authors: Ammour Basma , Boubchir Larbi , Bouden Toufik , Ramdani Messaoud
Published: January 2020

Multimodal biometrics technology has recently gained interest due to its capacity to overcome certain inherent limitations of the single biometric modalities and to improve the overall recognition rate. A common biometric recognition system consists of sensing, feature extraction, and matching modules. The robustness of the system depends much more on the reliability to extract relevant information from the single biometric traits. This paper proposes a new feature extraction technique for a multimodal biometric system using face–iris traits. The iris feature extraction is carried out using an efficient multi-resolution 2D Log-Gabor filter to capture textural information in different scales and orientations. On the other hand, the facial features are computed using the powerful method of singular spectrum analysis (SSA) in conjunction with the wavelet transform. SSA aims at expanding signals or images into interpretable and physically meaningful components. In this study, SSA is applied and combined with the normal inverse Gaussian (NIG) statistical features derived from wavelet transform. The fusion process of relevant features from the two modalities are combined at a hybrid fusion level. The evaluation process is performed on a chimeric database and consists of Olivetti research laboratory (ORL) and face recognition technology (FERET) for face and Chinese academy of science institute of automation (CASIA) v3.0 iris image database (CASIA V3) interval for iris. Experimental results show the robustness.
An Improved Droop-Based Control Strategy for MT-HVDC Systems
Authors: Mohammadi Fazel , Nazri Gholam-Abbas , Saif Mehrdad
Published: January 2020

This paper presents an improved droop-based control strategy for the active and reactive power-sharing on the large-scale Multi-Terminal High Voltage Direct Current (MT-HVDC) systems. As droop parameters enforce the stability of the DC grid, and allow the MT-HVDC systems to participate in the AC voltage and frequency regulation of the different AC systems interconnected by the DC grids, a communication-free control method to optimally select the droop parameters, consisting of AC voltage-droop, DC voltage-droop, and frequency-droop parameters, is investigated to balance the power in MT-HVDC systems and minimize AC voltage, DC voltage, and frequency deviations. A five-terminal Voltage-Sourced Converter (VSC)-HVDC system is modeled and analyzed in EMTDC/PSCAD and MATLAB software. Different scenarios are investigated to check the performance of the proposed droop-based control strategy. The simulation results show that the proposed droop-based control strategy is capable of sharing the active and reactive power, as well as regulating the AC voltage, DC voltage, and frequency of AC/DC grids in case of sudden changes, without the need for communication infrastructure. The simulation results confirm the robustness and effectiveness of the proposed droop-based control strategy.
Degradation Cost Analysis of Li-Ion Batteries in the Capacity Market with Different Degradation Models
Authors: Gailani Ahmed , Al-Greer Maher , Short Michael , Crosbie Tracey
Published: January 2020

Increased deployment of intermittent renewable energy plants raises concerns about energy security and energy affordability. Capacity markets (CMs) have been implemented to provide investment stability to generators and secure energy generation by reducing the number of shortage hours. The research presented in this paper contributes to answering the question of whether batteries can provide cost effective back up services for one year in this market. The analysis uses an equivalent circuit lithium ion battery model coupled with two degradation models (empirical and semi-empirical) to account for capacity fade during battery lifetime. Depending on the battery’s output power, four de-rating factors of 0.5 h, 1 h, 2 h and 4 h are considered to study which de-rating strategy can result in best economic profit. Two scenarios for the number of shortage hours per year in the CM are predicted based on the energy demand data of Great Britain and recent research. Results show that the estimated battery profit is maximum with 2 h and 1 h de-rating factors and minimum with 4 h and 0.5 h. Depending on the battery degradation model used, battery degradation cost can considerably impact the potential profit if the battery’s temperature is not controlled with adequate thermal management system. The empirical and semi-empirical models predict that the degradation cost is minimum at 5 °C and 25 °C respectively. Moreover, both models predict degradation is minimum at lower battery charge levels. While the battery’s capacity fade can be minimized to make some profits from the CM service, the increased shortage hours can make providing this service not economically viable.
Multi-Hop Relay Selection Based on Fade Durations
Authors: Assefa Gebremichail Aklilu , Beard Cory , Paropkari Rahul A.
Published: January 2020

In cooperative relaying, the selection of relays could be based on different parameters. The most well-known and frequently used metric is the signal-to-noise ratio (SNR). In this method of relay selection, the rapid fluctuation of the signal (i.e., fading) is not taken into account in the selection criteria. Such rapid signal change may cause significant loss of information, degrade signal quality for voice or video connections, or could make the channel coding fail. An alternative method of relay selection in a cooperative relay network is by considering fading. Such methods include average fade duration (AFD) and fade duration outage probability (FDOP), which are based on time correlation statistics. Both the AFD and the FDOP are computed in reference to a threshold value for signal quality. This work derives new formulas for two hop and three hop relay paths, with three hop paths given a penalty cost. Then optimization algorithms for each type of relay selection method are derived, including total path and link-by-link optimization. Simulation results provide optimal AFD and FDOP paths for various random network topologies. These paths are then compared to paths that would be found if SNR metrics were used instead. It is shown that SNR optimization results in much different performance. For cases of four sources and four relays, SNR based optimization frequently chose different relay paths, as low as only 63% of the same relay paths as FDOP or AFD optimizations. Because fade duration methods more accurately control the fading nature and true quality of the signals, the results here provide significant improvements in relay performance and allow two and three hop relay paths to be implemented effectively.
Voltage Space Vector Equivalent Substitution Fault-Tolerance Control for Cascaded H-Bridge Multilevel Inverter with Current-Tracking
Authors: Li Guohua , Liu Chunwu , Wang Yufeng
Published: January 2020

A novel fault-tolerant control method based on the equivalent substitution of voltage space vector for cascaded H-bridge multilevel inverter with current-tracking is proposed in this paper. With this method, the fault effects on the voltage vector of each sector of the cascaded inverter is analyzed first. Then, an algorithm to substitute the voltage vector in fault state is developed. In the fault state, if the voltage vector selected by the original algorithm cannot be used normally, the redundant voltage vector with the position coincidence is preferentially selected for equivalent substitution. If there is no redundant coincidence vector, select the other vector whose position and effect are closest to it. Compared with the commonly used N + 1 redundancy method, this method does not require the spare cascaded units and can be applied to any class cascaded H-bridge multilevel inverter with current-tracking to improve its reliability. Finally, the effectiveness of the proposed method is validated by simulation and experiment results.
Quick, Single-Frequency Dielectric Characterization of Blood Samples of Pediatric Cancer Patients by a Cylindrical Capacitor: Pilot Study
Authors: Ghanbarzadeh-Daghian Anooshe , Ahmadian Mohammad Taghi , Ghanbarzadeh-Dagheyan Ashkan
Published: January 2020

In this paper, as an application in biometrics, the electrical capacitance of normal and cancerous blood samples is experimentally determined in order to test the null hypothesis that the electrical capacitance of the two samples differs. The samples taken from healthy donors and patients diagnosed with different types of hematologic cancer are examined by a cylindrical capacitor with blood as its dielectric. The capacitance of these samples is measured at room temperature and a single frequency of 120 Hz, well below the frequency where β -dispersion starts, using a simple LCR meter device. The measurements indicate that the capacitance of the blood increases under applied electric field for a short period of time and asymptotically reaches its steady-state value. The measured values for the healthy group agreed with previous data in the literature. By the use of the unpaired two-tailed T-test, it is found that cancerous blood has higher values of capacitance when compared to normal samples ( p < 0.05 ). The reasons that might lead to such alterations are discussed from a biological perspective. Moreover, based on correlation calculations, a strong negative association is observed between blood capacitance and red blood cell (RBC) count in each group. Furthermore, sensitivity (SE) and specificity (SP) analysis demonstrates that for a threshold value between 15 and 17 for the capacitance value, both SE and SP are 100%. These preliminary findings on capacitance values may pave the way for the development of inexpensive and easy-to-use diagnosis tools for hematologic cancers at medical facilities and for in-home use, especially for children.
Multi-Timescale-Based Partial Optimal Control of a Proton-Exchange Membrane Fuel Cell
Authors: Milanovic Milos , Radisavljevic-Gajic Verica
Published: January 2020

This paper presents a Proton-Exchange Membrane Fuel Cell (PEMFC) transient model in stack current cycling conditions and its partial optimal control. The derived model is used for a specific application of the recently published multistage control technique developed by the authors. The presented control-oriented transient PEMFC model is an extension of the steady-state control-oriented model previously established by the authors. The new model is experimentally validated for transient operating conditions on the Greenlight Innovation G60 testing station where the comparison of the experimental and simulation results is presented. The derived five-state nonlinear control-oriented model is linearized, and three clusters of eigenvalues can be clearly identified. This specific feature of the linearized model is known as the three timescale system. A novel multistage optimal control technique is particularly suitable for this class of systems. It is shown that this control technique enables the designer to construct a local LQR, pole-placement or any other linear controller type at the subsystem level completely independently, which further optimizes the performance of the whole non-decoupled system.