bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of Ion Energy Distribution and Deposition of Ti Thin Films Using ABPPS Technology on Glass Substrate
Authors: Kim Dae-Chul , Kim Young-Woo , Kim Yong-Hyun , Park Jong-Bae , Kim Jong-Sik , Han Duk-Sun
Published: July 2021

Ion energy distributions (IEDs) play an important role in material processes and thin film deposition. We developed a newly designed multistep pulsed power supply (modulator) for the asymmetric bipolar pulsed power sputtering (ABPPS) technology and studied the effect of reverse bias voltage in improving the properties of thin films through Ti deposition. Using an ion energy analyzer, we confirmed IEDs and relative ion intensity under a reverse bias voltage of the modulator at the substrate position. A dense plasma was generated near the sputter target at reverse bias voltages above 300 V. Experiments were conducted by varying the bias voltage applied to the sputter target and the duty cycle of the modulator. Our results demonstrate that the in-house-built ABPPS system can be used to clean the sample surfaces without requiring additional energy sources or substrate bias and that thin films prepared using this system have a smoother surface than those prepared by conventional sputtering.
A Delay-Based Machine Learning Model for DMA Attack Mitigation
Authors: Gui Yutian , Bhure Chaitanya , Hughes Marcus , Saqib Fareena
Published: July 2021

Direct Memory Access (DMA) is a state-of-the-art technique to optimize the speed of memory access and to efficiently use processing power during data transfers between the main system and a peripheral device. However, this advanced feature opens security vulnerabilities of access compromise and to manipulate the main memory of the victim host machine. The paper outlines a lightweight process that creates resilience against DMA attacks minimal modification to the configuration of the DMA protocol. The proposed scheme performs device identification of the trusted PCIe devices that have DMA capabilities and constructs a database of profiling time to authenticate the trusted devices before they can access the system. The results show that the proposed scheme generates a unique identifier for trusted devices and authenticates the devices. Furthermore, a machine learning–based real-time authentication scheme is proposed that enables runtime authentication and share the results of the time required for training and respective accuracy.
Competition and Cooperation between Fluorine and Oxygen in SnO2:F Films
Authors: Sun Maolin , Gong Zhen , Yin Hang , Zhang Zheng , Li Yutong , Dong Haonan , Jing Weijun , Xie Decong , Liang Hailong , Wu Fayu
Published: July 2021

The interaction of oxygen and fluorine (F&O) in an F-doped SnO2 film, prepared by regulating oxygen partial pressure and the content of doped fluorine from 2.5 at% to 10 at%, was investigated in the large perspective through characterization methods including XRD, Raman spectroscopy, photoluminescence spectroscopy, wettability measurement and a Hall effect test system. The results show that F&O’s competitive and cooperative relationship would be reflected in the structure and electrical characteristics of SnO2 films. The oxygen action is overwhelming and restricts fluorine, so a growing number of F atoms occupy the position by the order of co-edge oxygen of tin–oxygen octahedron chains > oxygen vacancies > segregation, which leads to that carrier concentration modestly increasing from ~1015 to ~1017/cm−3. As oxygen action is inadequate to restrain fluorine, more F atoms are likely to enter the SnO2 lattice in a solid-solution way to replace the O atoms at the co-edge position of the octahedron chains, causing a dramatic increase in carrier concentration from ~1016 to ~1019/cm−3. Furthermore, by continuing to weaken oxygen action, only 2.5 at% of fluorine content could bring about a carrier concentration augment from ~1016/cm−3 to ~1018/cm−3, then going up to ~1021/cm−3 by post-annealing. However, the impairment of oxygen action contributes to a more effective doping of fluorine on SnO2 film. Such mutual action between fluorine and oxygen provides a direction for highly efficient production and tunable regulation of SnO2 film on demand.
Thermal Convection in the Core of Ganymede Inferred from Liquid Eutectic Fe-FeS Electrical Resistivity at High Pressures
Authors: Littleton Joshua A. H. , Secco Richard A. , Yong Wenjun
Published: July 2021

The core of Ganymede is suggested to be mainly Fe but with a significant proportion of S. Effects of S as a core constituent are freezing-point depression, allowing for a molten core at relatively low core temperatures, and modification of transport properties that can influence the dynamo and thermal evolution. The electrical resistivity of solid and liquid Fe-FeS (~24–30 wt.% S) was measured up to 5 GPa and thermal conductivity was calculated using the Wiedemann–Franz law. These first well-constrained experimental data on near eutectic Fe-FeS compositions showed intermediate values of electrical and thermal conductivities compared to the end-members. Eutectic temperatures were delineated from the solid to liquid transition, inferred from sharp changes in electrical resistivity, at each pressure. Combined with thermal models, our calculated estimates of the adiabatic heat flow of a molten Fe-FeS eutectic composition core model of Ganymede showed that thermal convection is permissible.
The Face-to-Face σ-Hole⋯σ-Hole Stacking Interactions: Structures, Energies, and Nature
Authors: Zhang Yu , Wang Weizhou
Published: July 2021

The existence of the π⋯π stacking interaction is well-known. Similarly, it is reasonable to assume the existence of the σ-hole⋯σ-hole stacking interaction. In this work, the structures, energies, and nature of the face-to-face σ-hole⋯σ-hole stacking interactions in the crystal structures have been investigated in detail by the quantum chemical calculations. The calculated results clearly show that the face-to-face σ-hole⋯σ-hole stacking interactions exist and have unique properties, although their strengths are not very significant. The energy component analysis reveals that, unlike many other dispersion-dominated noncovalent interactions in which the induction energies always play minor roles for their stabilities, for the face-to-face σ-hole⋯σ-hole stacking interaction the contribution of the induction energy to the total attractive energy is close to or even larger than that of the electrostatic energy. The structures, energies, and nature of the face-to-face σ-hole⋯σ-hole stacking interactions confined in small spaces have also been theoretically simulated. One of the important findings is that encapsulation of the complex bound by the face-to-face σ-hole⋯σ-hole stacking interaction can tune the electronic properties of the container.
A Review of Grain Boundary and Heterointerface Characterization in Polycrystalline Oxides by (Scanning) Transmission Electron Microscopy
Authors: Vahidi Hasti , Syed Komal , Guo Huiming , Wang Xin , Wardini Jenna Laurice , Martinez Jenny , Bowman William John
Published: July 2021

Interfaces such as grain boundaries (GBs) and heterointerfaces (HIs) are known to play a crucial role in structure-property relationships of polycrystalline materials. While several methods have been used to characterize such interfaces, advanced transmission electron microscopy (TEM) and scanning TEM (STEM) techniques have proven to be uniquely powerful tools, enabling quantification of atomic structure, electronic structure, chemistry, order/disorder, and point defect distributions below the atomic scale. This review focuses on recent progress in characterization of polycrystalline oxide interfaces using S/TEM techniques including imaging, analytical spectroscopies such as energy dispersive X-ray spectroscopy (EDXS) and electron energy-loss spectroscopy (EELS) and scanning diffraction methods such as precession electron nano diffraction (PEND) and 4D-STEM. First, a brief introduction to interfaces, GBs, HIs, and relevant techniques is given. Then, experimental studies which directly correlate GB/HI S/TEM characterization with measured properties of polycrystalline oxides are presented to both strengthen our understanding of these interfaces, and to demonstrate the instrumental capabilities available in the S/TEM. Finally, existing challenges and future development opportunities are discussed. In summary, this article is prepared as a guide for scientists and engineers interested in learning about, and/or using advanced S/TEM techniques to characterize interfaces in polycrystalline materials, particularly ceramic oxides.
Anomalous Propagation Characteristics of Airy Beam in Nonlinear Kerr Media
Authors: Shao Li , Wu Yun-Long , Ye Qing
Published: July 2021

The propagation characteristics of a single Airy beam in nonlinear Kerr media were numerically investigated by utilizing the split-step Fourier transform method. We show that in addition to normal breathing solitons, the anomalous bound states of Airy spatial solitons can also be formed, which are similar to the states formed in the interaction between two Airy beams in nonlinear media. This quasi-equilibrium state is formed by the interaction of the main soliton beam and side lobes of Airy beam due to their different propagation trajectories in the nonlinear media. Moreover, it has been shown the Airy spatial solitons in tree structure can be formed by adjusting the initial parameters in the interaction between the Airy beam and Kerr media.
18F-FDG PET/CT in Relapsed Endometrial Cancer Treated with Preoperative PD-1 Inhibitor Dostarlimab
Authors: Seban Romain-David , Donnadieu Anne , Journo Gabrielle , Bidard Francois-Clement , Richard Capucine , Rouzier Roman , Champion Laurence
Published: July 2021

Dostarlimab is an immune checkpoint inhibitor (ICI) targeting the Programmed-Death-1 (PD-1) co-receptor, recently approved by the European Medicines Agency (EMA) and the Food and Drug Administration (FDA) as a novel therapy for recurrent or advanced endometrial cancer. We report the case of a 64-year-old woman, experiencing vaginal recurrence with microsatellite instability high/hypermutated of a FIGO stage IA grade 2 endometrial endometrioid adenocarcinoma. She received preoperative chemotherapy with four cycles of carboplatin plus paclitaxel, with stable disease on pelvic magnetic resonance imaging (MRI) and fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET/CT). Dostarlimab (500 mg intravenously every 3 weeks) was then introduced. The subsequent evaluation after three perfusions demonstrated a complete metabolic response on 18F-FDG PET/CT according to immunotherapy-modified PET response criteria in solid tumors (imPERCIST) criteria, then confirmed by MRI according to immune response evaluation criteria in solid tumors (iRECIST). This clinical description suggests that 18F-FDG PET/CT might take place among available tools for guiding the preoperative management for recurrent endometrial cancer patients receiving dostarlimab immunotherapy that should be further explored through clinical trials.
PTH-rP and PTH-R1 Expression in Placentas from Pregnancies Complicated by Gestational Diabetes: New Insights into the Pathophysiology of Hyperglycemia in Pregnancy
Authors: Sirico Angelo , Dell’Aquila Marco , Tartaglione Linda , Moresi Sascia , Farì Giorgia , Pitocco Dario , Arena Vincenzo , Lanzone Antonio
Published: July 2021

Background: this study investigated the expression of parathyroid hormone-related protein (PTH-rP) and PTH/PTH-rP receptor PTH-R1 in placentas from women with gestational DM (GDM), and the relationship between PTH-R1 and PTH-rP expression and pregnancy characteristics. Methods: we prospectively enrolled 78 pregnant women with GDM, and immunochemistry for PTH-rP and PTH-R1 was performed on placentas. Patients were grouped according to the positivity of PTH-R1 or PTH-rP expression, and pregnancy characteristics were compared between the two groups. Results: PTH-rP and PTH-R1 expression were highest in the extravillous cytotrophoblast and in the decidua. In extravillous cytotrophoblast, PTH-rP expression was higher in women with abnormal at fasting glycemia compared to women with abnormal 60′ or 120′ glycemia (25/25, 50% vs. 6/28, 21.4%, χ2 = 6.12, p = 0.01), and PTH-R1 expression was higher in women with abnormal oral glucose tolerance test (OGTT) at fasting glycemia compared to women with abnormal 60′ or 120′ glycemia (37/50, 74% vs. 15/28, 53.6%, χ2 = 3.37, p = 0.06). In syncytiotrophoblast, PTH-rP-positive placentas were characterized by higher incidence of 1 min Apgar score < 7 (2/9, 22.2% vs. 2/69, 2.9%, χ2 = 6.11, p = 0.01) and maternal obesity (4/9, 44.4% vs. 11/69, 16.7%, χ2 = 3.81, p = 0.05). Conclusion: placental PTH-rP and PTH-R1 expression is dependent on the type of maternal hyperglycemia, and it is associated with adverse pregnancy outcomes.
Clinical and Image Characteristics of IgG4-Related Sclerosing Cholecystitis
Authors: Kuwatani Masaki , Sakamoto Naoya
Published: July 2021

Since autoimmune pancreatitis (AIP) was established as a new disease entity, sclerosing change with abundant immunoglobulin-4 (IgG4)-positive plasma cells, storiform fibrosis, and obliterative phlebitis are main pathological features in IgG4-related diseases. Regarding IgG4-related sclerosing cholecystitis (IgG4-CC), which is occasionally associated with AIP cases and is rarely isolated, there are no diagnostic criteria and insufficient perceptions of the image findings. Although there have been some reports on IgG4-CC, differentiation between IgG4-CC and gallbladder cancer is very difficult in some cases with a localized lesion. In this review, we especially focused on image findings of IgG4-CC and summarized its image features for diagnostic assistance. The ultrasonography and CT findings of IgG4-CC could be classified into diffuse and localized types. Based on these findings, the presence of wall thickening with an intact or smooth mucosal layer, followed by a homogenously thickened outer layer, would be a helpful morphological finding to distinguish IgG4-CC from gallbladder cancer.
Recognition of Connective Tissue Disease-Related Interstitial Pneumonia Based on Histological Score—A Validation Study of an Online Diagnostic Decision Support Tool
Authors: Ozasa Mutsumi , Zaizen Yoshiaki , Tabata Kazuhiro , Kataoka Kensuke , Sato Shuntaro , Bychkov Andrey , Sakamoto Noriho , Mukae Hiroshi , Kondoh Yasuhiro , Fukuoka Junya
Published: July 2021

Objectives: to evaluate the number of cases of idiopathic pulmonary fibrosis (IPF) that included histological features of connective tissue disease (CTD) and to check whether they demonstrated the clinical features of CTD, using a previously reported CTD-interstitial pneumonia (IP) index that histologically differentiates CTD-associated and idiopathic IP. Methods: patients diagnosed with IPF following video-assisted thoracoscopic biopsy through multidisciplinary team diagnosis between 2014 and 2017 were selected. Pathological observation was made by four pathologists who scored eight observational items needed for the CTD-IP index. Cases determined as CTD, by the CTD-IP index, were extracted, and their clinical features were compared. Results: a total of 94 cases of IPF were identified, of which 20 were classified into the CTD group using the CTD-IP index with reasonable interobserver agreement (k = 0.76). Cases pathologically classified into the CTD group were significantly associated with female sex, non-smoking history, autoantibody positivity, and CTD symptoms (p = 0.01, 0.03, 0.01, and 0.04, respectively). Conclusions: patients with IPF with pathological findings of CTD showed clinical characteristics similar to those of patients with CTD.
The Prognostic Factors and Required Degree Influencing the Activities of Daily Living and Gait in Brain Impairment Patients with Hemiplegia
Authors: Kim Seungsu , Park Jihye , Ko Young Jin
Published: July 2021

To improve the independence of brain impairment patients in ADL, we sought to identify influential parameters from information commonly collected in hospitals, prioritize the factors, and specify the degree to which those factors are necessary. In total, 64 patients with hemiplegia, who had been admitted to the one of the authors, were examined using various evaluation tools. Afterwards, we checked the difference between the capable group and the incapable group with an independent t-test or chi-squared test to determine the significant factors, and we prioritized the significant factors with Spearman’s rho test. The degree of their necessity was determined with the ROC curve. Standing balancing ability and hip joint and knee extensor strength are necessary in most ADL except for eating. In order to independently perform most ADL except eating and one gait cycle, the strength of the knee extensor and hip flexor was required to exceed grade 3 on the MRC scale. However, one gait cycle was possible even if the strength of the hip joint and knee extensors rated lower than 3 on the MRC scale. Additionally, upper limb motor recovery was required up to the distal parts in the order of bathing, dressing, and grooming.
Design and Implementation of Intelligent Inspection and Alarm Flight System for Epidemic Prevention
Authors: Fan Jiwei , Yang Xiaogang , Lu Ruitao , Xie Xueli , Li Weipeng
Published: July 2021

Unmanned aerial vehicles (UAV) and related technologies have played an active role in the prevention and control of novel coronaviruses at home and abroad, especially in epidemic prevention, surveillance, and elimination. However, the existing UAVs have a single function, limited processing capacity, and poor interaction. To overcome these shortcomings, we designed an intelligent anti-epidemic patrol detection and warning flight system, which integrates UAV autonomous navigation, deep learning, intelligent voice, and other technologies. Based on the convolution neural network and deep learning technology, the system possesses a crowd density detection method and a face mask detection method, which can detect the position of dense crowds. Intelligent voice alarm technology was used to achieve an intelligent alarm system for abnormal situations, such as crowd-gathering areas and people without masks, and to carry out intelligent dissemination of epidemic prevention policies, which provides a powerful technical means for epidemic prevention and delaying their spread. To verify the superiority and feasibility of the system, high-precision online analysis was carried out for the crowd in the inspection area, and pedestrians’ faces were detected on the ground to identify whether they were wearing a mask. The experimental results show that the mean absolute error (MAE) of the crowd density detection was less than 8.4, and the mean average precision (mAP) of face mask detection was 61.42%. The system can provide convenient and accurate evaluation information for decision-makers and meets the requirements of real-time and accurate detection.
Dendrogramic Representation of Data: CHSH Violation vs. Nonergodicity
Authors: Shor Oded , Benninger Felix , Khrennikov Andrei
Published: July 2021

This paper is devoted to the foundational problems of dendrogramic holographic theory (DH theory). We used the ontic–epistemic (implicate–explicate order) methodology. The epistemic counterpart is based on the representation of data by dendrograms constructed with hierarchic clustering algorithms. The ontic universe is described as a p-adic tree; it is zero-dimensional, totally disconnected, disordered, and bounded (in p-adic ultrametric spaces). Classical–quantum interrelations lose their sharpness; generally, simple dendrograms are “more quantum” than complex ones. We used the CHSH inequality as a measure of quantum-likeness. We demonstrate that it can be violated by classical experimental data represented by dendrograms. The seed of this violation is neither nonlocality nor a rejection of realism, but the nonergodicity of dendrogramic time series. Generally, the violation of ergodicity is one of the basic features of DH theory. The dendrogramic representation leads to the local realistic model that violates the CHSH inequality. We also considered DH theory for Minkowski geometry and monitored the dependence of CHSH violation and nonergodicity on geometry, as well as a Lorentz transformation of data.
Psychometric Properties of the Lasher and Faulkender Anxiety about Aging Scale (AAS) among Iranian Older Adults
Authors: Pakpour Amir H. , Namjoo Shamsedin , Sabahiazar Khadijeh , Jafarabadi Mohammad Asghari , Chattu Vijay Kumar , Allahverdipour Hamid
Published: July 2021

(1) Background: The older adult population of society is exposed to multiple stressors daily, such as the loss of loved ones, dysfunctional mobility, financial dependence, and suffering from numerous chronic illnesses. The present study aimed to assess the psychometric properties of the Anxiety about Aging Scale among older adults in Iran. (2) Methods: A sample of 703 community-dwelling older adults was recruited and screened using a standardized tool. The mean age of participants was 69.4 ± 8.1 years. The majority of participants were male (59.2%), married (66.6%), and illiterate (79.7%). A ‘forward-backward’ translation method was used in developing the Iranian version of the AAS for assessing the psychometric properties among older adults. Confirmatory factor analysis (CFA) and the Rasch model were used for construct validity. (3) Results: Applying CFA indicated that the model’s four original factors are the best solution, representing 55% of the total variance. The result of the CFA showed that this four-factor model had a good fit for the data. The findings were also confirmed by Rasch analysis. (4) Conclusions: The Persian version of the AAS is valid and reliable for measuring aging anxiety among Iranian older adults.
High-Efficiency Polarizer Reflectarray Antennas for Data Transmission Links from a CubeSat
Authors: Martinez-de-Rioja Eduardo , Martinez-de-Rioja Daniel , López-Sáez Rafael , Linares Ignacio , Encinar Jose A.
Published: July 2021

This paper presents two designs of high-efficiency polarizer reflectarray antennas able to generate a collimated beam in dual-circular polarization using a linearly polarized feed, with application to high-gain antennas for data transmission links from a Cubesat. First, an 18 cm × 18 cm polarizer reflectarray operating in the 17.2–22.7 GHz band has been designed, fabricated, and tested. The measurements of the prototype show an aperture efficiency of 52.7% for right-handed circular polarization (RHCP) and 57.3% for left-handed circular polarization (LHCP), both values higher than those previously reported in related works. Then, a dual-band polarizer reflectarray is presented for the first time, which operates in dual-CP in the frequency bands of 20 GHz and 30 GHz. The proposed antenna technology enables a reduction of the complexity and cost of the feed chain to operate in dual-CP, as a linear-to-circular polarizer is no longer required. This property, combined with the lightweight, flat profile and low fabrication cost of printed reflectarrays, makes the proposed antennas good candidates for Cubesat applications.
A Real-Time Monitoring Platform for Distributed Energy Resources in a Microgrid—Pilot Study in Oman
Authors: Hosseinzadeh Nasser , Al Maashri Ahmed , Tarhuni Naser , Elhaffar Abdelsalam , Al-Hinai Amer
Published: July 2021

This article presents the development of a platform for real-time monitoring of multi-microgrids. A small-scale platform has been developed and implemented as a prototype, which takes data from various types of devices located at a distance from each other. The monitoring platform is interoperable, as it allows several protocols to coexist. While the developed prototype is tested on small-scale distributed energy resources (DERs), it is done in a way to extend the concept for monitoring several microgrids in real scales. Monitoring strategies were developed for DERs by making a customized two-way communication channel between the microgrids and the monitoring center using a long-range bridged wireless local area network (WLAN). In addition, an informative and easy-to-use software dashboard was developed. The dashboard shows real-time information and measurements from the DERs—providing the user with a holistic view of the status of the DERs. The proposed system is scalable, modular, facilitates the interoperability of various types of inverters, and communicates data over a secure communication channel. All these features along with its relatively low cost make the developed real-time monitoring platform very useful for online monitoring of smart microgrids.
Time Series Segmentation Using Neural Networks with Cross-Domain Transfer Learning
Authors: Matias Pedro , Folgado Duarte , Gamboa Hugo , Carreiro André
Published: July 2021

Searching for characteristic patterns in time series is a topic addressed for decades by the research community. Conventional subsequence matching techniques usually rely on the definition of a target template pattern and a searching method for detecting similar patterns. However, the intrinsic variability of time series introduces changes in patterns, either morphologically and temporally, making such techniques not as accurate as desired. Intending to improve segmentation performances, in this paper, we proposed a Mask-based Neural Network (NN) which is capable of extracting desired patterns of interest from long time series, without using any predefined template. The proposed NN has been validated, alongside a subsequence matching algorithm, in two datasets: clinical (electrocardiogram) and human activity (inertial sensors). Moreover, the reduced dimension of the data in the latter dataset led to the application of transfer learning and data augmentation techniques to reach model convergence. The results have shown the proposed model achieved better segmentation performances than the baseline one, in both domains, reaching average Precision and Recall scores of 99.0% and 97.5% (clinical domain), along with 77.0% and 71.4% (human activity domain), introducing Neural Networks and Transfer Learning as promising alternatives for pattern searching in time series.
A New Cost-Efficient Design of a Reversible Gate Based on a Nano-Scale Quantum-Dot Cellular Automata Technology
Authors: Seyedi Saeid , Otsuki Akira , Navimipour Nima Jafari
Published: July 2021

Quantum-dot cellular automata (QCA) nanotechnology is a practical suggestion for replacing present silicon-based technologies. It provides many benefits, such as low power usage, high velocity, and an extreme density of logic functions on a chip. In contrast, designing circuits with no waste of information (reversible circuits) may further reduce energy losses. The Feynman gate has been recognized as one of the most famous QCA-based gates for this purpose. Since reversible gates are significant, this paper develops a new optimized reversible double Feynman gate that uses efficient arithmetic elements as its key structural blocks. Additionally, we used several modeling principles to make it consistent and more robust against noise. Moreover, we examined the suggested model and compared it to the previous models regarding the complexity, clocking, number of cells, and latency. Furthermore, we applied QCADesigner to monitor the outline and performance of the proposed gate. The results show an acceptable improvement via the designed double Feynman gate in comparison to the existing designs. Finally, the temperature and cost analysis indicated the efficiency of the proposed nan-scale gate.
Forecasting PM2.5 Concentration Using a Single-Dense Layer BiLSTM Method
Authors: Prihatno Aji Teguh , Nurcahyanto Himawan , Ahmed Md. Faisal , Rahman Md. Habibur , Alam Md. Morshed , Jang Yeong Min
Published: July 2021

In recent times, particulate matter (PM2.5) is one of the most critical air quality contaminants, and the rise of its concentration will intensify the hazard of cleanrooms. The forecasting of the concentration of PM2.5 has great importance to improve the safety of the highly pollutant-sensitive electronic circuits in the factories, especially inside semiconductor industries. In this paper, a Single-Dense Layer Bidirectional Long Short-term Memory (BiLSTM) model is developed to forecast the PM2.5 concentrations in the indoor environment by using the time series data. The real-time data samples of PM2.5 concentrations were obtained by using an industrial-grade sensor based on edge computing. The proposed model provided the best results comparing with the other existing models in terms of mean absolute error, mean square error, root mean square error, and mean absolute percentage error. These results show that the low error of forecasting PM2.5 concentration in a cleanroom in a semiconductor factory using the proposed Single-Dense Layer BiLSTM method is considerably high.
Discussion on IoT Security Recommendations against the State-of-the-Art Solutions
Authors: Chmiel Marta , Korona Mateusz , Kozioł Fryderyk , Szczypiorski Krzysztof , Rawski Mariusz
Published: July 2021

The Internet of Things (IoT) is an emerging concept comprising a wide ecosystem of interconnected devices and services. These technologies collect, exchange and process data in order to dynamically adapt to a specific context. IoT is tightly bound to cyber-physical systems and, in this respect, has relevant security implications. A need for IoT security guidelines was identified by the industry in the early 2010s. While numerous institutions across the globe have proposed recommendations with a goal to help developers, distributors and users to ensure a secure IoT infrastructure, a strict set of regulations for IoT security is yet to be established. In this paper, we aim to provide an overview of security guidelines for IoT proposed by various organizations, and evaluate some of the existing technologies applied to ensure IoT security against these guidelines. We gathered recommendations proposed by selected government organizations, international associations and advisory groups, and compiled them into a set of the most common and important considerations, divided into eight categories. Then we chose a number of representative examples from IoT security technologies and evaluated them against these criteria. While none of the examined solutions fulfill all recommendations on their own, the existing technologies introduced by those solutions could be combined to create a design framework which satisfies all the requirements of a secure IoT device. Further research on this matter could be beneficial. To the best of our knowledge, this is the first comprehensive survey to evaluate different security technologies for IoT device security against the compilation of criteria based on existing guidelines.
Credible Peer-to-Peer Trading with Double-Layer Energy Blockchain Network in Distributed Electricity Markets
Authors: Wang Longze , Xie Yu , Zhang Delong , Liu Jinxin , Jiang Siyu , Zhang Yan , Li Meicheng
Published: July 2021

Blockchain-based peer-to-peer (P2P) energy trading is one of the most viable solutions to incentivize prosumers in distributed electricity markets. However, P2P energy trading through an open-end blockchain network is not conducive to mutual credit and the privacy protection of stakeholders. Therefore, improving the credibility of P2P energy trading is an urgent problem for distributed electricity markets. In this paper, a novel double-layer energy blockchain network is proposed that stores private trading data separately from publicly available information. This blockchain network is based on optimized cross-chain interoperability technology and fully considers the special attributes of energy trading. Firstly, an optimized ring mapping encryption algorithm is designed to resist malicious nodes. Secondly, a consensus verification subgroup is built according to contract performance, consensus participation and trading enthusiasm. This subgroup verifies the consensus information through the credit-threshold digital signature. Thirdly, an energy trading model is embedded in the blockchain network, featuring dynamic bidding and credit incentives. Finally, the Erenhot distributed electricity market in China is utilized for example analysis, which demonstrates the proposed method could improve the credibility of P2P trading and realize effective supervision.
Economic Dispatch of CHP Units through District Heating Network’s Demand-Side Management
Authors: Rušeljuk Pavel , Lepiksaar Kertu , Siirde Andres , Volkova Anna
Published: July 2021

Optimisation of heat and electrical load distribution, where the objective function is the maximum efficiency of the CHP unit for a given load range, can be done considering the limitations of electrical power and the heat load. Simulating a real CHP unit with a district heating network shows that demand-side management can improve the overall economic efficiency of the CHP plant and increase the unit’s operating range in the electricity spot market. Economic dispatch makes it possible to determine a reasonable additional increase in the electric power of the CHP unit, and to optimise the supply temperature and mass flow of the district heating network. The results obtained and the analysis performed indicate that the proposed methodology provides logical results and can be used to calculate the efficiency indicators of the cogeneration of electrical and thermal energy. The problem of optimising the operating mode of the CHP unit was solved, which allows us to determine the optimal additional increase in the unit’s electrical load at a given heat load of consumers, which on average increases the CHP unit’s efficiency up to an additional 1.5%.
A Novel Control Approach to Hybrid Multilevel Inverter for High-Power Applications
Authors: Ali Muhammad , Hafeez Ghulam , Farooq Ajmal , Shafiq Zeeshan , Ali Faheem , Usman Muhammad , Mihet-Popa Lucian
Published: July 2021

This paper proposes a hybrid control scheme for a newly devised hybrid multilevel inverter (HMLI) topology. The circuit configuration of HMLI is comprised of a cascaded converter module (CCM), connected in series with an H-bridge converter. Initially, a finite set model predictive control (FS-MPC) is adopted as a control scheme, and theoretical analysis is carried out in MATLAB/Simulink. Later, in the real-time implementation of the HMLI topology, a hybrid control scheme which is a variant of the FS-MPC method has been proposed. The proposed control method is computationally efficient and therefore has been employed to the HMLI topology to mitigate the high-frequency switching limitation of the conventional MPC. Moreover, a comparative analysis is carried to illustrate the advantages of the proposed work that includes low switching losses, higher efficiency, and improved total harmonic distortion (THD) in output current. The inverter topology and stability of the proposed control method have been validated through simulation results in MATLAB/Simulink environment. Experimental results via low-voltage laboratory prototype have been added and compared to realize the study in practice.
Science Mapping: A Scientometric Review on Resource Curses, Dutch Diseases, and Conflict Resources during 1993–2020
Authors: Wong Chi-Swian
Published: July 2021

Over the past few decades, the wealth of Africa has not made African wealthy. There is a voicing that Africa is cursed, whether richly poor or poorly rich. Sub-Saharan Africa is commonplace for political turbulence, as well as humanitarian and economic misery. In such a catastrophic situa-tion, political economics studies have focused on the Resource Curses, Dutch Diseases, and Con-flict Resources in this area. A systematic scientometric analysis of this field would be beneficial but is currently lacking in the academic literature. Using VOSviewer and CiteSpace, this review fills the void by analyzing the 1783 articles published in the WoS SSCI Collection between 1993 and 2020 on the “Resource Curses”, “Dutch Diseases”, and “Conflict Resources”. The author dis-cusses recent papers with disruptive potential, references with the most robust citation explora-tions, and cooperation networks between authors and institutes. Three hotspots were detected: the causes and effects of the Resource curses; the interaction among the Resource Curses, Dutch Diseases, and Conflict Resources; the factors that affect rent collection and regime resilience. While the literature on the “Resource curse” and “Dutch Disease” has been around longer, studies on “Conflict Resources” are picking up quickly. Conflict Resources were characterized by active citation exploration keywords and multiple active co-citation clusters, including possibly groundbreaking articles. There is a massive overlap between the three strings of literature, but each one has its emphasis.
Measures of Functional Reliability of Two-Lane Highways
Authors: Ostrowski Krzysztof , Budzynski Marcin
Published: July 2021

Rural two-lane highways are the most common road type both in Poland and globally. In terms of kilometres, their length is by far greater than that of motorways and expressways. They are roads of one carriageway for each direction, which makes the overtaking of slower vehicles possible only when there is a gap in the stream of traffic moving from the opposite direction. Motorways and express roads are dual carriageways that are expected to support high speed travel mainly over long distances. Express roads have somewhat lower technical parameters and a lower speed limit than motorways. Two-lane highways are used for both short- and long-distance travel. The paper presents selected studies conducted in Poland in 2016–2018 on rural two-lane highways and focuses on the context of the need for their reliability. The research was carried out on selected short and longer road sections located in various surroundings, grouped in terms of curvature change rate CCR, longitudinal slopes and cross-sections (width of lanes and shoulders). The studies of traffic volumes, travel time and travel speed, as well as traffic density, will be used to analyze traffic performance and identify measures of travel time reliability. The analyzed roads were characterized by good technical parameters and significant variability of traffic volume throughout the day, week and year. Some roads experience congestion, i.e., situations in which traffic volume Q is close to or above respective road capacity C. In order to determine the form of the suitable reliability measures, it will be important to determine the extent to which a road’s geometric and traffic characteristics impact travel speed and time. The paper presents well-known reliability measures for dual carriageways and proposes new measures, along with an evaluation of their usefulness in the assessment of the functioning of two-lane highways.
Renewable Energy, Economic Growth and Economic Development Nexus: A Bibliometric Analysis
Authors: Oliveira Henrique , Moutinho Víctor
Published: July 2021

The present research aims to conduct a systemic review on Renewable Energy, Economic Growth and Economic Development and look for links between the papers published between 2008 and May 2021. Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, it was possible to reach a sample of 111 articles selected by Web of Science and a sample of 199 academic articles selected by Scopus in that specific period. The analysis of the group of Renewable and Non-renewable Energy Consumption, Economic Growth and Economic Development shows that most of the articles published in this subsample use the quantitative methodology in economic sciences. The results indicate that research on the subject has a growing trend and that most of the articles are post-2015 publications. In addition, China has been the leading nation in published works. The journal Renewable and Sustainable Energy Reviews is considered the most relevant in this category, and Sustainability has the most publications. Finally, a research gap was identified to be explored, lacking studies aimed at understanding the consumption of renewable energies and economic development and studies that focus on renewable energies and economic growth in less developed economies.
Vortex Shedding Suppression: A Review on Modified Bluff Bodies
Authors: Teimourian Amir , Teimourian Hanifa
Published: July 2021

Vortex shedding phenomenon behind bluff bodies and its destructive unsteady wake can be controlled by employing active and passive flow control methods. In this quest, researchers employed experimental fluid dynamics (EFD), computational fluid dynamics (CFD) and an analytical approach to investigate such phenomena to reach a desired outcome. This study reviews the available literature on the flow control of vortex shedding behind bluff bodies and its destructive wake through the modification of the geometry of the bluff body. Various modifications on the bluff body geometries namely perforated bluff bodies, permeable and porous mesh, corner modification and wavy cylinder have been reviewed. The effectiveness of these methods has been discussed in terms of drag variation, wake structure modifications and Strouhal number alteration.
The Driving Factors of Subtropical Mature Forest Productivity: Stand Structure Matters
Authors: Ren Siyuan , Yang Qingsong , Liu Heming , Shen Guochun , Zheng Zemei , Zhou Shuangshuang , Liang Mengfang , Yin Huimin , Zhou Zhengkang , Wang Xihua
Published: July 2021

Forest productivity (increment of above-ground biomass) is determined by biodiversity but also by stand structure attributes. However, the relative strengths of these drivers in determining productivity remain controversial in subtropical forests. In this study, we analyzed a tree growth data from 500 plots with in a 20 ha mature subtropical forest in eastern China. We used spatial simultaneous autoregressive error models to examine the effects of diversity variables (species richness, evenness, and composition), stand structural attributes (stand density, tree size range and diversity), environmental factors (topography and soil), and initial above-ground biomass (AGB) on productivity. We also applied structural equation models to quantify the relative importance of diversity, stand structure, environmental factors, and initial AGB in determining forest productivity. Our results showed that stand structure together with diversity and initial AGB governed forest productivity. Tree size diversity (DBH Shannon’s diversity index) had the largest positive effect on forest productivity. These results provide new evidence that structural explanatory variables have greater contributions to productivity for mature subtropical forests, strongly supporting the niche complementarity hypothesis. Our work highlights the importance of tree size diversity in promoting high forest productivity, and suggests that regulating and conserving complexity of forest stand structure should be among the most important goals in subtropical forest management.
Genetic Structure, Differentiation and Originality of Pinus sylvestris L. Populations in the East of the East European Plain
Authors: Vasilyeva Yulia , Chertov Nikita , Nechaeva Yulia , Sboeva Yana , Pystogova Nina , Boronnikova Svetlana , Kalendar Ruslan
Published: July 2021

In order to carry out activities aimed at conservation and rational use of forest resources; it is necessary to study the main forest-forming plant species in detail. Scots pine (Pinus sylvestris L., Pinaceae) is mainly found in the boreal forests of Eurasia and is not so often encountered in the east of the East European Plain. The aim of the study was to study the genetic diversity, structure and differentiation of Scots pine populations in the east of the East European Plain. We studied ten populations of P. sylvestris using the Inter Simple Sequence Repeats (ISSR)-based DNA polymorphism detection method. Natural populations are demonstrated by relatively high rates of genetic diversity (He = 0.167; ne = 1.279; I = 0.253). At the same time, there is a tendency for a decrease in the genetic diversity of the studied populations of P. sylvestris from west to east. Analysis of the genetic structure shows that the studied populations are highly differentiated (GST = 0.439), the intrapopulation component accounts for about 56% of the genetic diversity. Using various algorithms for determining the spatial genetic structure, it is found that the studied populations form two groups of populations in accordance with geographic location. With the help of a genetic originality coefficient, populations with specific and typical gene pools are identified. They are recommended as sources of genetic diversity and reserves for the conservation of genetic resources of the species.
A Response Surface Methodology (RSM) Approach for Optimizing the Attenuation of Human IgE-Reactivity to β-Lactoglobulin (β-Lg) by Hydrostatic High Pressure Processing
Authors: Sun Xin , Vivien Chua Jialing , Le Quynh Anh , Trujillo Francisco J. , Oh Mi-Hwa , Campbell Dianne E. , Mehr Sam , Lee Nanju Alice
Published: July 2021

The response surface methodology (RSM) and central composite design (CCD) technique were used to optimize the three key process parameters (i.e., pressure, temperature and holding time) of the high-hydrostatic-pressure (HHP) processing either standalone or combined with moderate thermal processing to modulate molecular structures of β-lactoglobulin (β-Lg) and α-lactalbumin (α-La) with reduced human IgE-reactivity. The RSM model derived for HHP-induced molecular changes of β-Lg determined immunochemically showed that temperature (temp), pressure (p2) and the interaction between temperature and time (t) had statistically significant effects (p < 0.05). The optimal condition defined as minimum (β-Lg specific) IgG-binding derived from the model was 505 MPa at 56 °C with a holding time of 102 min (R2 of 0.81 and p-value of 0.01). The validation carried at the optimal condition and its surrounding region showed that the model to be underestimating the β-Lg structure modification. The molecular change of β-Lg was directly correlated with HHP-induced dimerization in this study, which followed a quadratic equation. The β-Lg dimers also resulted in the undetectable human IgE-binding.
Influence of Different Alkali Sulfates on the Shrinkage, Hydration, Pore Structure, Fractal Dimension and Microstructure of Low-Heat Portland Cement, Medium-Heat Portland Cement and Ordinary Portland Cement
Authors: Li Yang , Zhang Hui , Huang Minghui , Yin Haibo , Jiang Ke , Xiao Kaitao , Tang Shengwen
Published: July 2021

In cement-based materials, alkalis mainly exist in the form of different alkali sulfates. In this study, the impacts of different alkali sulfates on the shrinkage, hydration, pore structure, fractal dimension and microstructure of low-heat Portland cement (LHPC), medium-heat Portland cement (MHPC) and ordinary Portland cement (OPC) are investigated. The results indicate that alkali sulfates magnify the autogenous shrinkage and drying shrinkage of cement-based materials with different mineral compositions, which are mainly related to different pore structures and hydration processes. LHPC has the lowest shrinkage. Otherwise, the effect of alkali sulfates on the autogenous shrinkage is more profound than that of drying shrinkage. Compared with the pore size distribution, the fractal dimension can better characterize the shrinkage properties of cement-based materials. It is noted that the contribution of K2SO4 (K alkali) to the promotion effect of shrinkage on cement-based materials is more significant than that of Na2SO4 (Na alkali), which cannot be ignored. The microstructure investigation of different cement-based materials by means of nuclear magnetic resonance (NMR), mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) shows that this effect may be related to the different pore structures, crystal forms and morphologies of hydration products of cement-based materials.