bluuebunny/crossref_metadata_2025 huggingface dataset:
Mesenchymal Stromal Cell Differentiation for Generating Cartilage and Bone-Like Tissues In Vitro
Authors: Monaco Graziana , Ladner Yann D. , El Haj Alicia J. , Forsyth Nicholas R. , Alini Mauro , Stoddart Martin J.
Published: August 2021

In the field of tissue engineering, progress has been made towards the development of new treatments for cartilage and bone defects. However, in vitro culture conditions for human bone marrow mesenchymal stromal cells (hBMSCs) have not yet been fully defined. To improve our understanding of cartilage and bone in vitro differentiation, we investigated the effect of culture conditions on hBMSC differentiation. We hypothesized that the use of two different culture media including specific growth factors, TGFβ1 or BMP2, as well as low (2% O2) or high (20% O2) oxygen tension, would improve the chondrogenic and osteogenic potential, respectively. Chondrogenic and osteogenic differentiation of hBMSCs isolated from multiple donors and expanded under the same conditions were directly compared. Chondrogenic groups showed a notable upregulation of chondrogenic markers compared with osteogenic groups. Greater sGAG production and deposition, and collagen type II and I accumulation occurred for chondrogenic groups. Chondrogenesis at 2% O2 significantly reduced ALP gene expression and reduced type I collagen deposition, producing a more stable and less hypertrophic chondrogenic phenotype. An O2 tension of 2% did not inhibit osteogenic differentiation at the protein level but reduced ALP and OC gene expression. An upregulation of ALP and OC occurred during osteogenesis in BMP2 containing media under 20% O2; BMP2 free osteogenic media downregulated ALP and also led to higher sGAG release. A higher mineralization was observed in the presence of BMP2 during osteogenesis. This study demonstrates how the modulation of O2 tension, combined with tissue-specific growth factors and media composition can be tailored in vitro to promote chondral or endochondral differentiation while using the same donor cell population.
S1P Increases VEGF Production in Osteoblasts and Facilitates Endothelial Progenitor Cell Angiogenesis by Inhibiting miR-16-5p Expression via the c-Src/FAK Signaling Pathway in Rheumatoid Arthritis
Authors: Huang Chien-Chung , Tseng Tzu-Ting , Liu Shan-Chi , Lin Yen-You , Law Yat-Yin , Hu Sung-Lin , Wang Shih-Wei , Tsai Chun-Hao , Tang Chih-Hsin
Published: August 2021

Angiogenesis is a critical process in the formation of new capillaries and a key participant in rheumatoid arthritis (RA) pathogenesis. Vascular endothelial growth factor (VEGF) stimulation of endothelial progenitor cells (EPCs) facilitates angiogenesis and the progression of RA. Phosphorylation of sphingosine kinase 1 (SphK1) produces sphingosine-1-phosphate (S1P), which increases inflammatory cytokine production, although the role of S1P in RA angiogenesis is unclear. In this study, we evaluated the impact of S1P treatment on VEGF-dependent angiogenesis in osteoblast-like cells (MG-63 cells) and the significance of SphK1 short hairpin RNA (shRNA) on S1P production in an in vivo model. We found significantly higher levels of S1P and VEGF expression in synovial fluid from RA patients compared with those with osteoarthritis by ELISA analysis. Treating MG-63 cells with S1P increased VEGF production, while focal adhesion kinase (FAK) and Src siRNAs and inhibitors decreased VEGF production in S1P-treated MG-63 cells. Conditioned medium from S1P-treated osteoblasts significantly increased EPC tube formation and migration by inhibiting miR-16-5p synthesis via proto-oncogene tyrosine-protein kinase src (c-Src) and FAK signaling in chick chorioallantoic membrane (CAM) and Matrigel plug assays. Infection with SphK1 shRNA reduced angiogenesis, articular swelling and cartilage erosion in the ankle joints of mice with collagen-induced arthritis (CIA). S1P appears to have therapeutic potential in RA treatment.
Effects of Climate Change on the Future of Heritage Buildings: Case Study and Applied Methodology
Authors: Huerto-Cardenas Harold Enrique , Aste Niccolò , Del Pero Claudio , Della Torre Stefano , Leonforte Fabrizio
Published: August 2021

Heritage buildings and the precious artworks contained therein, represent inestimable cultural and artistic evidence from the past that must be properly preserved for future generations. In the last decades, climate change has gained relevance and is becoming crucial to assess the building performance under such effect to provide timely mitigation actions to preserve our cultural heritage. In this regard, this paper outlines a method that combines different experimental activities and tools to forecast possible future risks due to climate change for the conservation of the artworks and provide its application in a relevant case study in Italy, the Duomo di Milano. In detail, the suggested method consists of the monitoring of the building indoor climate to validate a simulation model, defining possible future scenarios based on the Intergovernmental Panel on Climate Change (IPCC) projections, and evaluation of the future conservation risks of the main artworks. The results of the analysis carried out, show that for some artworks (e.g., stone sculptures, some organic materials, etc.), the conservation conditions will not worsen compared to the current situation, while for others (e.g., paintings, wooden objects, etc.) the risk of deterioration is expected to increase substantially. This study helps to understand how the future climate can affect the indoor environment of a huge masonry building and allow to plan targeted mitigation strategies aimed to reduce the future risks.
Study on Laser Surface Hardening Behavior of 42CrMo Press Brake Die
Authors: Wang Huizhen , Zhai Yuewen , Zhou Leyu , Zhang Zibo
Published: August 2021

Laser surface hardening is a promising surface technology to enhance the properties of surfaces. This technology was used on the 42CrMo press brake die. Its hardening behavior was investigated by using scanning electron microscopy and electron backscattering diffraction. The results indicated that the martensite in the hardening zone was significantly finer than that in the substrate. There were many low-angle grain boundaries in the martensite of the hardening zone, and the kernel average misorientation and grain orientation spread in the hardening zone grains were obviously greater, which further improved the hardness of the hardening zone, especially near the substrate. The microstructure and the properties of the blade maintained excellent uniformity with treatment by single-pass laser surface hardening with a spot size of 2 mm, scanning speed of 1800 mm/min, and power of 2200 W. The hardness of the hardening zone was 1.6 times higher than that of the base material, and the thickness of the hardening zone reached 1.05 mm.
Modeling and Simulation of Vacuum Low Pressure Carburizing Process in Gear Steel
Authors: Guo Jingyu , Deng Xiaohu , Wang Huizhen , Zhou Leyu , Xu Yueming , Ju Dongying
Published: August 2021

A combination of simulation and experimental approaches to optimize the vacuum carburizing process is necessary to replace the costly experimental trial-and-error method in time and resources. In order to accurately predict the microstructure evolution and mechanical properties of the vacuum carburizing process, a multi-field multi-scale coupled model considering the interaction of temperature, diffusion, phase transformation, and stress was established. Meanwhile, the improved model is combined with the heat treatment software COSMAP to realize the simulation of the low-pressure vacuum carburizing process. The low-pressure vacuum carburizing process of 20CrMo gear steel was simulated by COSMAP and compared with the experimental results to verify the model. The results indicated that the model could quantitatively obtain the carbon concentration distribution, Fe-C phase fraction, and hardness distribution. It can be found that the carbon content gradually decreased from the surface to the center. The surface carbon concentration is relatively high only after the carburizing stage. With the increase in diffusion time, the surface carbon concentration decreases, and the carburized layer depth increases. The simulated surface carbon concentration results and experimental results are in good agreement. However, there is an error between calculations and observations for the depth of the carburized layer. The error between simulation and experiment of the depth of carburized layer is less than 6%. The simulated surface hardness is 34 HV lower than the experimental surface hardness. The error of surface hardness is less than 5%, which indicates that the simulation results are reliable. Furthermore, vacuum carburizing processes with different diffusion times were simulated to achieve the carburizing target under specific requirements. The results demonstrated that the optimum process parameters are a carburizing time of 42 min and a diffusion time of 105 min. This provides reference and guidance for the development and optimization of the vacuum carburizing process.
Hydrostatic Bearing Characteristics Investigation of a Spherical Piston Pair with an Annular Orifice Damper in Spherical Pump
Authors: Guan Dong , Zhou Zhuxin , Zhang Chun
Published: August 2021

The spherical pump is a totally new hydraulic concept, with spherical piston and hydrostatic bearing, in order to eliminate the direct contact between the piston and cylinder cover. In this paper, the governing Reynolds equation under spherical coordinates has been solved and the hydrostatic bearing characteristics are systematically investigated. The operating sensitivities of the proposed spherical hydrostatic bearing, with respect to the piston radius, film beginning angle, film ending angle, film thickness, and temperature, are studied. The load carrying capacity, pressure drop coefficient, stiffness variation of the lubricating films, leakage properties, and leakage flow rates are comprehensively discussed. The related findings provide a fundamental basis for designing the high-efficient spherical pump under multiple operating conditions. Besides, these related results and mechanisms can also be utilized to design and improve other kinds of annular orifice damper spherical hydraulic bearing systems.
Effect of Deformation on the Microstructure of Cold-Rolled TA2 Alloy after Low-Temperature Nitriding
Authors: Liu Guotan , Sun Huanzheng , Wang Enhong , Sun Keqiang , Zhu Xiaoshuo , Fu Yudong
Published: August 2021

In order to improve the low hardness and poor wear resistance of TA2, this paper proposes a composite process of cold-rolling and low-temperature plasma nitriding with recrystallization. This composite modification process can effectively achieve the dual goals of modifying the matrix structure and surface of TA2 alloy simultaneously. The cold-rolling experimental results indicate that when the deformation rate increases, the small-sized grains in the sample increase significantly, and the grain orientation changes from TD (transverse direction) to RD (rolling direction) and then to TD. The nitriding experimental results indicate that the {0001} basal surface texture deflected from the TD direction to the RD direction, {10-10} cylindrical texture components gradually increased, and the special orientation phenomenon of cylindrical and conical texture disappeared, it can be seen that an increase in the deformation rate promotes recrystallization. The XRD test results indicate that after low-temperature nitriding, metastable nitriding phase TiN0.26 is formed on the surface of TA2. The SEM morphology of the cross-section shows that a relatively special nitrided zone is formed, and mechanical performance test results indicate the wear resistance and hardness of the alloy increased.
A Novel Quality Control Method for the Determination of the Refractive Index of Oil-in-Water Creams and Its Correlation with Skin Hydration
Authors: Adejokun Deborah Adefunke , Dodou Kalliopi
Published: August 2021

The sensory properties of cosmetic products can influence consumers’ choice. The accurate correlation of sensory properties, such as skin hydration, with the material properties of the formulation could be desirable. In this study, we aimed to demonstrate a new method for the in vitro measurement of the refractive indices (RIs) of turbid creams. The critical wavelength of each cream was obtained through direct measurement using a sun protection factor (SPF) meter; the wavelength value was then applied in the Sellmeier equation to determine the RI. The results obtained from the in vitro skin hydration measurement for each cream correlated with their RI values. This suggests that RI measurements could be a useful predictive tool for the ranking of creams in terms of their skin hydration effects.
Reuse of Sintered Sludge from Municipal Sewage Treatment Plants for the Production of Lightweight Aggregate Building Mortar
Authors: Li Changyong , Zhang Xiaoyan , Zhang Bingxin , Tan Yunfei , Li Fenglan
Published: August 2021

In recent years, the sludge produced by municipal sewage treatment plants has become an important recyclable resource for producing green building materials. After the systematic processing of incineration and particle formation, the sintered sludge can be processed into fine lightweight aggregate to produce building mortar with the controlled leaching of heavy metals and radioactivity. In this paper, to increase its economic and environmental benefits, mortar with sintered sludge aggregate was made by cement admixing of fly ash or limestone powder. The water-to-binder ratio was set at three levels—0.82, 0.68, and 0.62—and either flay ash or limestone powder was used to replace equal masses of cement at 10%, 20%, or 30%. Eighteen groups of mortar were studied to evaluate their workability, air content, compressive strength, tensile adhesive strength, dry density, and thermal conductivity. The results indicate that with a proper water-to-binder ratio, and the replacement ratio of fly ash or limestone powder, the mortar can be produced with good workability, consistency, water-retention rate, layering degree, and setting time. The mortar made with sintered sludge lightweight aggregate, designated by the mix-proportion method for conventional lightweight aggregate mortar, did not meet the target strength, although the compressive strength of mortar was no less than 3.0 MPa, which meets the strength grade M2.5. The tensile adhesive strength reached 0.18 MPa. The mortar was super lightweight with a dry density less than 400 kg/m3, and a thermal conductivity within 0.30~0.32 W/(m⋅K). The effects of water-to-binder ratio and replacement ratio of fly ash or limestone powder on the above properties are discussed with test results. The study provides a basis for using sintered sludge lightweight aggregate for building mortar.
Friction-Induced Biphasic Cutaneous Amyloidosis
Authors: Gambichler Thilo , Susok Laura , Segert Marc H.
Published: August 2021

Primary cutaneous amyloidoses (PCA) are a group of conditions characterized by deposition of amyloid in previously normal skin, without association with other skin or systemic diseases. We describe a Kazakhstani female with a 30-year history of increasingly spreading hyperpigmented macular as well papular skin lesions on her upper trunk accompanied by pruritus. Moreover, her medical history included intensely rubbing her skin with a cotton towel following bathing and showering. On the basis of the clinical and histopathological findings, the diagnosis of biphasic cutaneous amyloidosis was made. The present unusual case of biphasic cutaneous amyloidosis can be subsumed under mechanically-induced forms of cutaneous amyloidosis. In conclusion, the present case underscores the necessity to explore carefully the patient’s history in order to discover the cause of PCA.
The Diagnostic Usefulness of 131I-SPECT/CT at Both Radioiodine Ablation and during Long-Term Follow-Up in Patients Thyroidectomized for Differentiated Thyroid Carcinoma: Analysis of Tissue Risk Factors Ascertained at Surgery and Correlated with Metastasis Appearance
Authors: Spanu Angela , Nuvoli Susanna , Marongiu Andrea , Gelo Ilaria , Mele Luciana , De Vito Andrea , Rondini Maria , Madeddu Giuseppe
Published: August 2021

131I Single-photon emission computerized tomography/computerized tomography (SPECT/CT) in the management of patients thyroidectomized for differentiated thyroid carcinoma (DTC) was further investigated. Retrospectively, 106 consecutive DTC patients were enrolled at the first radioiodine ablation, 24 at high risk (H), 61 at low risk (L) and 21 at very low risk (VL). 131I whole-body scan (WBS) and SPECT/CT were performed after therapeutic doses using a hybrid dual-head gamma camera. At ablation, SPECT/CT correctly classified 49 metastases in 17/106 patients with a significantly (p < 0.001) more elevated number than WBS which evidenced 32/49 foci in 13/17 cases. In this case, 86/106 patients could be monitored in the follow-up including 13/17 cases with metastases already at post-therapeutic scans. SPECT/CT after radioiodine diagnostic doses more correctly than WBS ascertained disease progression in 4/13 patients, stable disease in other 4/13 cases and disease improvement in the remaining 5/13 cases. Further 13/86 patients with only residues at post-therapeutic scans showed at SPECT/CT 16 neck lymph node (LN) metastases, three unclear and 13 occult at WBS. Significant involvement of some tissue risk factors with metastasis appearance was observed, such as minimal extrathyroid tumor extension and neck LN metastases. These risk factors should be carefully considered in DTC patient follow-up where 131I-SPECT/CT routinely use is suggested as a support tool of WBS.
Mouth Washing Impaired SARS-CoV-2 Detection in Saliva
Authors: Costa Monique Melo , Benoit Nicolas , Tissot-Dupont Hervé , Million Matthieu , Pradines Bruno , Granjeaud Samuel , Almeras Lionel
Published: August 2021

Background: A previous study demonstrated the performance of the Salivette® (SARSTEDT, Numbrecht, Germany) as a homogeneous saliva collection system to diagnose COVID-19 by RT-qPCR, notably for symptomatic and asymptomatic patients. However, for convalescent patients, the corroboration of molecular detection of SARS-CoV-2 in paired nasopharyngeal swabs (NPS) and saliva samples was unsatisfactory. Objectives: The aim of the present work was to assess the concordance level of SARS-CoV-2 detection between paired sampling of NPSs and saliva collected with Salivette® at two time points, with ten days of interval. Results: A total of 319 paired samples from 145 outpatients (OP) and 51 healthcare workers (HW) were collected. Unfortunately, at day ten, 73 individuals were lost to follow-up, explaining some kinetic missing data. Due to significant waiting rates at hospitals, most of the patients ate and/or drank while waiting for their turn. Consequently, mouth washing was systematically proposed prior to saliva collection. None of the HW were diagnosed as SARS-CoV-2 positive using NPS or saliva specimens at both time points (n = 95) by RT-qPCR. The virus was detected in 56.3% (n = 126/224) of the NPS samples from OP, but solely 26.8% (n = 60/224) of the paired saliva specimens. The detection of the internal cellular control, the human RNase P, in more than 98% of the saliva samples, underlined that the low sensitivity of saliva specimens (45.2%) for SARS-CoV-2 detection was not attributed to an improper saliva sample storing or RNA extraction. Conclusions: This work revealed that mouth washing decreased viral load of buccal cavity conducting to impairment of SARS-CoV-2 detection. Viral loads in saliva neo-produced appeared insufficient for molecular detection of SARS-CoV-2. At the time when saliva tests could be a rapid, simple and non-invasive strategy to assess large scale schoolchildren in France, the determination of the performance of saliva collection becomes imperative to standardize procedures.
Shortening the Time of the Identification and Antimicrobial Susceptibility Testing on Positive Blood Cultures with MALDI-TOF MS
Authors: Tsai Ya-Wen , Lin Ting-Chia , Chou Hsiu-Yin , Hung Huei-Ya , Tan Che-Kim , Wu Li-Ching , Feng I-Jung , Shiue Yow-Ling
Published: August 2021

The current processes used in clinical microbiology laboratories take ~24 h for incubation to identify the bacteria after the blood culture has been confirmed as positive and fa further ~24 h to report the results of antimicrobial susceptibility tests (ASTs). Patients with suspected bloodstream infection are treated with empiric broad-spectrum antibiotics but delayed targeted antimicrobial therapy. This study aimed to develop a method with a significantly shortened turnaround time for clinical application by identifying the optimal incubation period of a subculture. A total of 188 positive blood culture samples obtained from Nov. 2019 to Aug. 2020 were included. Compared to the conventional 24-h incubation for bacterial identification, our approach achieved 96.1% and 97.4% identification accuracy after shortening the incubation time to 4.5 and 3.5 h for gram-positive (GP) and gram-negative (GN) bacterial samples, respectively. Samples from short-term incubation without any intermediate step or process were directly subjected to analysis with the Phoenix M50 AST. Compared to the conventional disk diffusion AST, the category agreements for GP (excluding Streptococcus spp.), Streptococcus spp., and GN bacterial samples were 91.8%, 97.5%, and 92.7%, respectively. Our approach significantly reduced the average turnaround time from 48 h to 28 h for reporting bacterial identity and decreased average AST from 72 h to 50.3 h compared to the conventional methods. Accordingly, this approach allows a physician to prescribe the appropriate antibiotic(s) ~21.7 h earlier, thereby improving patient outcomes.
Dirichlet Polynomials and Entropy
Authors: Spivak David I. , Hosgood Timothy
Published: August 2021

A Dirichlet polynomial d in one variable y is a function of the form d(y)=anny+⋯+a22y+a11y+a00y for some n,a0,…,an∈N. We will show how to think of a Dirichlet polynomial as a set-theoretic bundle, and thus as an empirical distribution. We can then consider the Shannon entropy H(d) of the corresponding probability distribution, and we define its length (or, classically, its perplexity) by L(d)=2H(d). On the other hand, we will define a rig homomorphism h:Dir→Rect from the rig of Dirichlet polynomials to the so-called rectangle rig, whose underlying set is R⩾0×R⩾0 and whose additive structure involves the weighted geometric mean; we write h(d)=(A(d),W(d)), and call the two components area and width (respectively). The main result of this paper is the following: the rectangle-area formula A(d)=L(d)W(d) holds for any Dirichlet polynomial d. In other words, the entropy of an empirical distribution can be calculated entirely in terms of the homomorphism h applied to its corresponding Dirichlet polynomial. We also show that similar results hold for the cross entropy.
Causal Information Rate
Authors: Kim Eun-jin , Guel-Cortez Adrian-Josue
Published: August 2021

Information processing is common in complex systems, and information geometric theory provides a useful tool to elucidate the characteristics of non-equilibrium processes, such as rare, extreme events, from the perspective of geometry. In particular, their time-evolutions can be viewed by the rate (information rate) at which new information is revealed (a new statistical state is accessed). In this paper, we extend this concept and develop a new information-geometric measure of causality by calculating the effect of one variable on the information rate of the other variable. We apply the proposed causal information rate to the Kramers equation and compare it with the entropy-based causality measure (information flow). Overall, the causal information rate is a sensitive method for identifying causal relations.
High-Dimensional Separability for One- and Few-Shot Learning
Authors: Gorban Alexander N. , Grechuk Bogdan , Mirkes Evgeny M. , Stasenko Sergey V. , Tyukin Ivan Y.
Published: August 2021

This work is driven by a practical question: corrections of Artificial Intelligence (AI) errors. These corrections should be quick and non-iterative. To solve this problem without modification of a legacy AI system, we propose special ‘external’ devices, correctors. Elementary correctors consist of two parts, a classifier that separates the situations with high risk of error from the situations in which the legacy AI system works well and a new decision that should be recommended for situations with potential errors. Input signals for the correctors can be the inputs of the legacy AI system, its internal signals, and outputs. If the intrinsic dimensionality of data is high enough then the classifiers for correction of small number of errors can be very simple. According to the blessing of dimensionality effects, even simple and robust Fisher’s discriminants can be used for one-shot learning of AI correctors. Stochastic separation theorems provide the mathematical basis for this one-short learning. However, as the number of correctors needed grows, the cluster structure of data becomes important and a new family of stochastic separation theorems is required. We refuse the classical hypothesis of the regularity of the data distribution and assume that the data can have a rich fine-grained structure with many clusters and corresponding peaks in the probability density. New stochastic separation theorems for data with fine-grained structure are formulated and proved. On the basis of these theorems, the multi-correctors for granular data are proposed. The advantages of the multi-corrector technology were demonstrated by examples of correcting errors and learning new classes of objects by a deep convolutional neural network on the CIFAR-10 dataset. The key problems of the non-classical high-dimensional data analysis are reviewed together with the basic preprocessing steps including the correlation transformation, supervised Principal Component Analysis (PCA), semi-supervised PCA, transfer component analysis, and new domain adaptation PCA.
Self-Organization, Entropy Generation Rate, and Boundary Defects: A Control Volume Approach
Authors: Sekhar Jainagesh A.
Published: August 2021

Self-organization that leads to the discontinuous emergence of optimized new patterns is related to entropy generation and the export of entropy. Compared to the original pattern that the new, self-organized pattern replaces, the new features could involve an abrupt change in the pattern-volume. There is no clear principle of pathway selection for self-organization that is known for triggering a particular new self-organization pattern. The new pattern displays different types of boundary-defects necessary for stabilizing the new order. Boundary-defects can contain high entropy regions of concentrated chemical species. On the other hand, the reorganization (or refinement) of an established pattern is a more kinetically tractable process, where the entropy generation rate varies continuously with the imposed variables that enable and sustain the pattern features. The maximum entropy production rate (MEPR) principle is one possibility that may have predictive capability for self-organization. The scale of shapes that form or evolve during self-organization and reorganization are influenced by the export of specific defects from the control volume of study. The control volume (CV) approach must include the texture patterns to be located inside the CV for the MEPR analysis to be applicable. These hypotheses were examined for patterns that are well-characterized for solidification and wear processes. We tested the governing equations for bifurcations (the onset of new patterns) and for reorganization (the fine tuning of existing patterns) with published experimental data, across the range of solidification morphologies and nonequilibrium phases, for metallic glass and featureless crystalline solids. The self-assembling features of surface-texture patterns for friction and wear conditions were also modeled with the entropy generation (MEPR) principle, including defect production (wear debris). We found that surface texture and entropy generation in the control volume could be predictive for self-organization. The main results of this study provide support to the hypothesis that self-organized patterns are a consequence of the maximum entropy production rate per volume principle. Patterns at any scale optimize a certain outcome and have utility. We discuss some similarities between the self-organization behavior of both inanimate and living systems, with ideas regarding the optimizing features of self-organized pattern features that impact functionality, beauty, and consciousness.
Research on the Fastest Detection Method for Weak Trends under Noise Interference
Authors: Li Guang , Liang Jing , Yue Caitong
Published: August 2021

Trend anomaly detection is the practice of comparing and analyzing current and historical data trends to detect real-time abnormalities in online industrial data-streams. It has the advantages of tracking a concept drift automatically and predicting trend changes in the shortest time, making it important both for algorithmic research and industry. However, industrial data streams contain considerable noise that interferes with detecting weak anomalies. In this paper, the fastest detection algorithm “sliding nesting” is adopted. It is based on calculating the data weight in each window by applying variable weights, while maintaining the method of trend-effective integration accumulation. The new algorithm changes the traditional calculation method of the trend anomaly detection score, which calculates the score in a short window. This algorithm, SNWFD–DS, can detect weak trend abnormalities in the presence of noise interference. Compared with other methods, it has significant advantages. An on-site oil drilling data test shows that this method can significantly reduce delays compared with other methods and can improve the detection accuracy of weak trend anomalies under noise interference.
Internship of Accounting Students in the Form of E-Learning: Insights from Poland
Authors: Januszewski Arkadiusz , Grzeszczak Małgorzata
Published: August 2021

The COVID-19 pandemic has imposed on us not only e-learning with higher education providers, but also triggered considerable difficulties in organization internships. Institutions and enterprises that used to be eager to take interns have refused to do so. In these conditions, the key objective for the Faculty of Management at the UTP University in Bydgoszcz was to organize e-internships to ensure a working environment similar to the real working conditions of the accounting department. A new internship program was developed that implemented the assumptions of active learning, by virtue of the case study approach, computer-based learning environments, and a comprehensive task simulating the work of the accounting department in the form of a multi-step project. The key objective of this article is to present the results of research in the form of a survey on how the students majoring in Finance and Accounting perceive the proposed internship method. The results show that an internship in the form of e-learning with the proposed education methods is appreciated by the students. E-learning does not necessarily have to be less effective than traditional learning. The use of platforms and the selecting of adequate methods can enhance the activity of students, supporting self-education and independent task performance.
FO-Sketch: A Fast Oblivious Sketch for Secure Network Measurement Service in the Cloud
Authors: Liu Lingtong , Shen Yulong , Zeng Shuiguang , Zhang Zhiwei
Published: August 2021

Network measurements are the foundation for network applications. The metrics generated by those measurements help applications improve their performance of the monitored network and harden their security. As severe network attacks using leaked information from a public cloud exist, it raises privacy and security concerns if directly deployed in network measurement services in a third-party public cloud infrastructure. Recent studies, most notably OblivSketch, demonstrated the feasibility of alleviating those concerns by using trusted hardware and Oblivious RAM (ORAM). As their performance is not good enough, and there are certain limitations, they are not suitable for broad deployment. In this paper, we propose FO-Sketch, a more efficient and general network measurement service that meets the most stringent security requirements, especially for a large-scale network with heavy traffic volume and burst traffic. Let a mergeable sketch update the local flow statistics in each local switch; FO-Sketch merges (in an Intel SGX-created enclave) these sketches obliviously to form a global “one big sketch” in the cloud. With the help of Oblivious Shuffle, Divide and Conquer, and SIMD speedup, we optimize all of the critical routines in our FO-Sketch to make it 17.3x faster than a trivial oblivious solution. While keeping the same level of accuracy and packet processing throughput as non-oblivious Elastic Sketch, our FO-Sketch needs only ∼4.5 MB enclave memory space in total to record metrics and for PORAM to store the global sketch in the cloud. Extensive experiments demonstrate that, for the recommended setting, it takes only ∼ 0.6 s in total to rebuild those data during each measurement interval.
Derogation of Physical Layer Security Breaches in Maturing Heterogeneous Optical Networks
Authors: Armghan Ammar
Published: August 2021

The evolution journey of optical network (ON) towards heterogeneous and flexible frameworks with high order of applications is continued from the last decade. Furthermore, the prominence of optical security, amount of transmitted data, bandwidth, and dependable presentation are heightened. The performance of ON is degraded in view of various natures of attacks at the physical layer, such as service disrupting and access to carrier data. In order to deal with such security breaches, new and efficient ON must be identified. So, this paper elaborates a detailed structure on physical layer security for heterogeneous ON. Possible mechanisms, such as Elliptic-curve Diffie–Hellman (ECDH), are used to treat a physical layer attack, and an efficient framework is proposed in this paper for 64 quadrature amplitude modulation-based orthogonal frequency division multiplex (64QAM-OFDM) ONs. Finally, theoretical and simulation validations are presented, and the effective results of the proposed method and viewpoint are concluded.
A Low Area High Speed FPGA Implementation of AES Architecture for Cryptography Application
Authors: Kumar Thanikodi , Reddy Kasarla , Rinaldi Stefano , Parameshachari Bidare , Arunachalam Kavitha
Published: August 2021

Nowadays, a huge amount of digital data is frequently changed among different embedded devices over wireless communication technologies. Data security is considered an important parameter for avoiding information loss and preventing cyber-crimes. This research article details the low power high-speed hardware architectures for the efficient field programmable gate array (FPGA) implementation of the advanced encryption standard (AES) algorithm to provide data security. This work does not depend on the Look-Up Table (LUTs) for the implementation the SubBytes and InvSubBytes stages of transformations of the AES encryption and decryption; this new architecture uses combinational logical circuits for implementing SubBytes and InvSubBytes transformation. Due to the elimination of LUTs, unwanted delays are eliminated in this architecture and a subpipelining structure is introduced for improving the speed of the AES algorithm. Here, modified positive polarity reed muller (MPPRM) architecture is inserted to reduce the total hardware requirements, and comparisons are made with different implementations. With MPPRM architecture introduced in SubBytes stages, an efficient mixcolumn and invmixcolumn architecture that is suited to subpipelined round units is added. The performances of the proposed AES-MPPRM architecture is analyzed in terms of number of slice registers, flip flops, number of slice LUTs, number of logical elements, slices, bonded IOB, operating frequency and delay. There are five different AES architectures including LAES, AES-CTR, AES-CFA, AES-BSRD, and AES-EMCBE. The LUT of the AES-MPPRM architecture designed in the Spartan 6 is reduced up to 15.45% when compared to the AES-BSRD.
High PSRR Wide Supply Range Dual-Voltage Reference Circuit for Bio-Implantable Applications
Authors: Zawawi Ruhaifi Bin Abdullah , Choi Hojong , Kim Jungsuk
Published: August 2021

On-chip systems are challenging owing to the limited size of the components, such as the capacitor bank in the rectifier. With a small on-chip capacitor, the output voltage of the rectifier might ring if the circuit experiences significant changes in current. The reference circuit is the first block after the rectifier, and the entire system relies on its robustness. A fully integrated dual-voltage reference circuit for bio-implantable applications is presented. The proposed circuit utilizes nonlinear current compensation techniques that significantly decrease supply variations and reject high-supply ripples for various frequencies. The reference circuit was verified using a 0.35 µm complementary metal-oxide semiconductor (CMOS) process. Maximum PSRR values of −112 dB and −128 dB were obtained. With a supply range from 2.8 to 12 V, the proposed design achieves 0.916 and 1.5 mV/V line regulation for the positive and negative reference circuits, respectively.
An Efficient Distributed Elliptic Positioning for Underground Remote Sensing
Authors: Al-Samahi Sanaa S. , Ansaf Huda , Ansaf Bahaa I. K.
Published: August 2021

Remote surveying of unknown bound geometries, such as the mapping of underground water supplies and tunnels, remains a challenging task. The obstacles and absorption in media make the long-distance telecommunication and localization process inefficient due to mobile sensors’ power limitations. This work develops a new short-range sequential localization approach to reduce the required amount of signal transmission power. The developed algorithm is based on a sequential localization process that can utilize a multitude of randomly distributed wireless sensors while only employing several anchors in the process. Time delay elliptic and frequency range techniques are employed in developing the proposed algebraic closed-form solution. The proposed method is highly effective as it reaches the Cramer–Rao Lower Bound performance level. The estimated positions can act as initializations for the iterative Maximum Likelihood Estimator (MLE) via the Taylor series linearization to acquire even higher positioning accuracy as needed. By reducing the need for high power at the transmit modules in the sensors, the developed localization approach can be used to design a compact sensor with low power consumption and greater longevity that can be utilized to explore unknown bounded geometries for life-long efficient observation mapping.
Rain Attenuation Scaling in South Korea: Experimental Results and Artificial Neural Network
Authors: Samad Md Abdus , Diba Feyisa Debo , Choi Dong-You
Published: August 2021

Scaling rain attenuation parameters will significantly benefit the quick monitoring of rain attenuation in a particular channel with previously known results or in situ setup attenuation measurements. Most of the rain attenuation scaling techniques have been derived for slant links. In this study, we also applied frequency and polarization scaling techniques for terrestrial link applications. We collected real measured datasets from research paper publications and examined those datasets using International Telecommunication Union-Radiocommunication sector (ITU-R) models (P.530-17, P.618-13). Our analyzed results show that existing long-term frequency and polarization scaling rain attenuation models (ITU-R P.618-13 for slant links and ITU-R P.530-17 for terrestrial links) show reduced performance for frequency and polarization scaling measured locations in South Korea. Hence, we proposed a new scaling technique using artificial neural networks from the measured rain attenuation data of slant and terrestrial links in South Korea. The experimental results confirm that the proposed Artificial Neural Network (ANN)-based scaling model shows satisfactory performance to predict attenuation for frequency and vertical polarization scaling.
Smart Agriculture Cloud Using AI Based Techniques
Authors: Junaid Muhammad , Shaikh Asadullah , Hassan Mahmood Ul , Alghamdi Abdullah , Rajab Khairan , Al Reshan Mana Saleh , Alkinani Monagi
Published: August 2021

This research proposes a generic smart cloud-based system in order to accommodate multiple scenarios where agriculture farms using Internet of Things (IoTs) need to be monitored remotely. The real-time and stored data are analyzed by specialists and farmers. The cloud acts as a central digital data store where information is collected from diverse sources in huge volumes and variety, such as audio, video, image, text, and digital maps. Artificial Intelligence (AI) based machine learning models such as Support Vector Machine (SVM), which is one of many classification types, are used to accurately classify the data. The classified data are assigned to the virtual machines where these data are processed and finally available to the end-users via underlying datacenters. This processed form of digital information is then used by the farmers to improve their farming skills and to update them as pre-disaster recovery for smart agri-food. Furthermore, it will provide general and specific information about international markets relating to their crops. This proposed system discovers the feasibility of the developed digital agri-farm using IoT-based cloud and provides solutions to problems. Overall, the approach works well and achieved performance efficiency in terms of execution time by 14%, throughput time by 5%, overhead time by 9%, and energy efficiency by 13.2% in the presence of competing smart farming baselines.
Heuristic Methodology for Planning AC Rural Medium-Voltage Distribution Grids
Authors: Montoya Oscar Danilo , Serra Federico Martin , De Angelo Cristian Hernan , Chamorro Harold R. , Alvarado-Barrios Lazaro
Published: August 2021

The optimal expansion of AC medium-voltage distribution grids for rural applications is addressed in this study from a heuristic perspective. The optimal routes of a distribution feeder are selected by applying the concept of a minimum spanning tree by limiting the number of branches that are connected to a substation (mixed-integer linear programming formulation). In order to choose the caliber of the conductors for the selected feeder routes, the maximum expected current that is absorbed by the loads is calculated, thereby defining the minimum thermal bound of the conductor caliber. With the topology and the initial selection of the conductors, a tabu search algorithm (TSA) is implemented to refine the solution with the help of a three-phase power flow simulation in MATLAB for three different load conditions, i.e., maximum, medium, and minimum consumption with values of 100%, 60%, and 30%, respectively. This helps in calculating the annual costs of the energy losses that will be summed with the investment cost in conductors for determining the final costs of the planning project. Numerical simulations in two test feeders comprising 9 and 25 nodes with one substation show the effectiveness of the proposed methodology regarding the final grid planning cost; in addition, the heuristic selection of the calibers using the minimum expected current absorbed by the loads provides at least 70% of the calibers that are contained in the final solution of the problem. This demonstrates the importance of using adequate starting points to potentiate metaheuristic optimizers such as the TSA.
Battery Energy Storage Contribution to System Adequacy
Authors: Dratsas Pantelis A. , Psarros Georgios N. , Papathanassiou Stavros A.
Published: August 2021

The objective of this paper is to evaluate the contribution of energy storage systems to resource adequacy of power systems experiencing increased levels of renewables penetration. To this end, a coherent methodology for the assessment of system capacity adequacy and the calculation of energy storage capacity value is presented, utilizing the Monte Carlo technique. The main focus is on short-duration storage, mainly battery energy storage systems (BESS), whose capacity values are determined for different power and energy configurations. Alternative operating policies (OPs) are implemented, prioritizing system cost or reliability, to demonstrate the significant effect storage management may have on its contribution to system adequacy. A medium-sized island system is used as a study case, applying a mixed integer linear programming (MILP) generation scheduling model to simulate BESS and system operation under each OP, in order to determine capacity contribution and overall performance in terms of renewable energy sources (RES) penetration, system operating cost and BESS lifetime expectancy. This study reveals that BESS contribution to system adequacy can be significant (capacity credit values up to ~85%), with energy capacity proving to be the most significant parameter. Energy storage may at the same time enhance system reliability, reduce generation cost and support RES integration, provided that it is appropriately managed; a combined reliability-oriented and cost-driven management approach is shown to yield optimal results.
Charge Density-Versus Time-Controlled Pulse Anodization in the Production of PAA-Based DBRs for MIR Spectral Region
Authors: Białek Ewelina , Szwachta Grzegorz , Kaliszewski Miron , Norek Małgorzata
Published: August 2021

A robust and reliable method for fabricating porous anodic alumina (PAA)-based distributed Bragg reflectors (DBRs), operating in mid-infrared (MIR) spectral region, is presented. The method relies on application of high (UH) and low (UL) voltage pulse sequence repeated in cycles. PAA-based DBR consists of alternating high-(dH) and low-porosity (dL) layers translated directly into periodically varied refractive index. Two anodization modes were used: time- and charge density-controlled mode. The former generated dH + dL pairs with non-uniform thickness (∆d) and effective refractive index (∆neff). It is supposed, that owing to a compensation effect between the ∆d and ∆neff, the photonic stopbands (PSBs) were symmetrical and intensive (transmittance close to zero). Under the charge density-controlled mode dH + dL pairs of uniform thickness were formed. However, the remaining ∆neff provided an asymmetrical broadening of PSBs. Furthermore, it is demonstrated that the spectral position of the PSBs can be precisely tuned in the 3500–5500 nm range by changing duration of voltage pulses, the amount of charge passing under subsequent UH and UL pulses, and by pore broadening after the electrochemical synthesis. The material can be considered to be used as one-dimensional transparent photonic crystal heat mirrors for solar thermal applications.