bluuebunny/crossref_metadata_2025 huggingface dataset:
Excimer laser coronary atherectomy prior to paclitaxel-coated balloon angioplasty for de novo coronary artery lesions
Authors: Shibui Takashi , Tsuchiyama Takaaki , Masuda Shinichiro , Nagamine Sho
Published: April 2020

This study aimed to evaluate the efficacy and safety of excimer laser coronary atherectomy (ELCA) prior to paclitaxel-coated balloon angioplasty for de novo coronary artery lesions. This retrospective observational study analyzed 118 eligible patients with de novo coronary artery disease whose only percutaneous coronary intervention was a drug-coated balloon angioplasty (i.e., no subsequent stent placement). Data related to our primary outcomes of interest—incidence of major adverse cardiovascular and cerebral events (MACCE), and incidence of procedural complications (bailout stenting and minor complications)—were collected and retrospectively analyzed. ELCA was used significantly more often in the cases of main branch and ostial lesions (i.e., of the circumflex, right coronary, or left anterior descending arteries, or high lateral branch), normally associated with poor treatment outcomes (55.6% vs. 14.3%, p < 0.0005). However, the two groups were not different in terms of cumulative incidence as estimated by the Kaplan–Meier method (log-rank test, p = 0.603) and a causal relationship between ELCA and MACCE was not identified (OR, 2.223; 95% CI, 0.614–8.047; p = 0.223). This study confirms the safety of ELCA prior to paclitaxel DCB angioplasty to treat de novo coronary artery lesions. While difficult-to-treat lesions were significantly more prevalent in the group treated by ELCA, the study revealed similar efficiency as conventional pre-dilation methods. Our findings provide grounds for a prospective randomized trial with consistent lesion and procedural characteristics to evaluate the potential benefits of combining paclitaxel DCB angioplasty following ELCA for de novo coronary artery lesions.
In operando monitoring of wood transformation during pretreatment with ionic liquids
Authors: Viell Jörn , Szekely Noemi K. , Mangiapia Gaetano , Hövelmann Claas , Marks Caroline , Frielinghaus Henrich
Published: April 2020

The conversion of lignocellulosic biomass or wood into chemicals still poses a challenge due to the recalcitrance of this composite-like material consisting of lignin, hemicellulose and cellulose. A very high accessibility of cellulose is reported by a pretreatment with ionic liquids that enables high conversion rates by enzymatic hydrolysis. However, the underlying mechanisms have not yet been monitored in operando nor are they fully understood. We monitored the transformation of wood in ionic liquids using small-angle neutron scattering to observe changes in the material in operando and to elucidate the intrinsic effects. The data analysis shows three different stages that is (1) impregnation, (2) the formation of voids and (3) increasing structure size within cellulose fibrils. This consecutive mechanism coincides with macroscopic disintegration of the tissue. The analysis further reveals that the reduction of order in longitudinal direction along the fiber axis is a prerequisite for disintegration of cells along the radial direction. This understanding supports further research and development of pretreatment processes starting from lignocellulosic raw material.

Graphic abstract
Learning Foreign Language Vocabulary with Gestures and Pictures Enhances Vocabulary Memory for Several Months Post-Learning in Eight-Year-Old School Children
Authors: Andrä Christian , Mathias Brian , Schwager Anika , Macedonia Manuela , von Kriegstein Katharina
Published: April 2020

The integration of gestures and pictures into pedagogy has demonstrated potential for improving adults’ learning of foreign language (L2) vocabulary. However, the relative benefits of gestures and pictures on children’s L2 vocabulary learning have not been formally evaluated. In three experiments, we investigated the effects of gesture-based and picture-based learning on 8-year-old primary school children’s acquisition of novel L2 vocabulary. In each experiment, German children were trained over 5 consecutive days on auditorily presented, concrete and abstract, English vocabulary. In Experiments 1 and 2, gesture enrichment (auditorily presented L2 words accompanied with self-performed gestures) was compared with a non-enriched baseline condition. In Experiment 3, gesture enrichment was compared with picture enrichment (auditorily presented words accompanied with pictures). Children performed vocabulary recall and translation tests at 3 days, 2 months, and 6 months post-learning. Both gesture and picture enrichment enhanced children’s test performance compared with non-enriched learning. Benefits of gesture and picture enrichment persisted up to 6 months after training and occurred for both concrete and abstract words. Gesture-enriched learning was hypothesized to boost learning outcomes more than picture-enriched learning on the basis of previous findings in adults. Unexpectedly, however, we observed similar benefits of gesture and picture enrichment on children’s L2 learning. These findings suggest that both gestures and pictures enhance children’s L2 learning and that performance benefits are robust over long timescales.
Cutting the Network, Knotting the Line: a Linaeological Approach to Network Analysis
Authors: Pálsson Gísli
Published: April 2020

Network methods have seen a rapid rise in archaeology in recent years. There are still concerns regarding how well formal networks are able to effectively model local interaction. These are often present in the so-called qualitative network approaches—studies that tend to be based on close readings of relations between entities and the way they form dynamic networks of agents. Such studies have demonstrated the value in scrutinizing the way in which relations might be acted on in practice, and how that might differ from expected results. But rarely do such studies produce network data of the kind analyzed by formal network analytical methods. Formal approaches, on the other hand, blur the specificity of individual relations and trade much of their specificity for the ability to make general statements about relations across large datasets. More generally, the modality of the relation/edge is a crucial way in which formal network analysis differs from other prevalent relational approaches popular in archaeology today, where the substantivity of individual relations is paramount. Such relations are often seen as starting points for subsequent hybridizations that radically alter, if only temporarily, the structure of their respective networks. I argue that a key step in allowing networks to reformulate from initial, data-driven network schemata is the introduction of a more symmetrical agency between the node and the edge. In this article, I discuss how ethnographic sources can be used to achieve this for archaeological survey data. I use assemblage theory as a framework to explore the potential the edge has to offer archaeological network modelling. While assemblage theory is helpful for this purpose, the lack of a computational formality to assemblage theory immediately places it at odds with network science. As a complement, I will also employ the computational ontology CIDOC-CRM to more explicitly articulate the character of links between nodes in archaeological networks. The paper will end by suggesting a method of network modelling which integrates the line as a key source of agency. As a nod to Ingold’s call for an increased emphasis on the line, I call this approach network linaeology.
The Role of Virtual Communities in Gambling and Gaming Behaviors: A Systematic Review
Authors: Sirola Anu , Savela Nina , Savolainen Iina , Kaakinen Markus , Oksanen Atte
Published: April 2020

Gambling opportunities are facilitated by the growth of the Internet and social media platforms. Digital games also increasingly include monetary features, such as microtransactions, blurring the line between gambling and gaming. The Internet provides a variety of virtual communities for gamblers and gamers, but comprehensive research on these communities and their relevance in gambling and monetary gaming behaviors remains scarce. This paper summarizes research of online gambling and monetary gaming communities based on a systematic literature review. A systematic literature search was conducted from five databases: Scopus, Web of Science, PsycINFO, Social Science Premium Collection, and EBSCOhost. The search was limited to empirical articles that focused on gambling or gaming involving money and examined online interaction between gamblers or gamers. Preliminary search resulted in 1056 articles, from which 55 were selected for the analyses based on pre-determined criteria. According to results, online communities serve different functions in gambling and gaming behaviors. Gambling communities are typically forums for discussing and sharing gambling experiences, strategies, and tips as well as gambling problems, while gaming communities are inherently embedded inside a game being an essential part of the gaming experience. Identification with virtual communities influences gambling behavior and monetary gaming behavior through mechanisms of perceived norms, social influence, and community feedback. Whereas some gambling communities may provide protection from excessive gambling habits, gaming communities seem to solely motivate gaming behavior and purchase intentions. The role of online communities should be acknowledged in prevention and treatment of gambling and gaming problems.
The impact of hydrothermal carbonization on the surface functionalities of wet waste materials for water treatment applications
Authors: Niinipuu Mirva , Latham Kenneth G. , Boily Jean-François , Bergknut Magnus , Jansson Stina
Published: April 2020

Hydrothermal carbonization (HTC) is an energy-efficient thermochemical process for converting wet waste products into value added materials for water treatment. Understanding how HTC influences the physicochemical properties of the resultant materials is critical in optimizing the process for water treatment, where surface functionality and surface area play a major role. In this study, we have examined the HTC of four wet waste streams, sewage sludge, biosludge, fiber sludge, and horse manure at three different temperatures (180 °C, 220 °C, and 260 °C). The physicochemical properties of these materials were examined via FTIR, SEM and BET with their adsorption capacity were assessed using methylene blue. The yield of solid material after hydrothermal carbonization (hydrochar) decreased with increasing temperature for all samples, with the largest impact on horse manure and fiber sludge. These materials also lost the highest degree of oxygen, while HTC had minimal impact on biosludge and sewage sludge. The differences here were due to the varying compositions of each waste material, FTIR identified resonances related to cellulose in horse manure and fiber sludge, which were not detected in biosludge and sewage sludge. Adsorption capacities varied between 9.0 and 68 mg g−1 with biosludge HTC at 220 °C adsorbing the highest amount. Adsorption also dropped drastically at the highest temperature (260 °C), indicating a correlation between adsorption capacity and HTC conditions. This was attributed to the loss of oxygen functional groups, which can contribute to adsorption. These results suggest that adsorption properties can be tailored both by selection of HTC temperature and feedstock.
Structural and functional brain network alterations in prenatal alcohol exposed neonates
Authors: Roos Annerine , Fouche Jean-Paul , Ipser Jonathan C. , Narr Katherine L. , Woods Roger P. , Zar Heather J. , Stein Dan J. , Donald Kirsten A.
Published: April 2020

Prenatal alcohol exposure leads to alterations in cognition, behavior and underlying brain architecture. However, prior studies have not integrated structural and functional imaging data in children with prenatal alcohol exposure. The aim of this study was to characterize disruptions in both structural and functional brain network organization after prenatal alcohol exposure in very early life. A group of 11 neonates with prenatal alcohol exposure and 14 unexposed controls were investigated using diffusion weighted structural and resting state functional magnetic resonance imaging. Covariance networks were created using graph theoretical analyses for each data set, controlling for age and sex. Group differences in global hub arrangement and regional connectivity were determined using nonparametric permutation tests. Neonates with prenatal alcohol exposure and controls exhibited similar global structural network organization. However, global functional networks of neonates with prenatal alcohol exposure comprised of temporal and limbic hubs, while hubs were more distributed in controls representing an early default mode network. On a regional level, controls showed prominent structural and functional connectivity in parietal and occipital regions. Neonates with prenatal alcohol exposure showed regionally, predominant structural and functional connectivity in several subcortical regions and occipital regions. The findings suggest early functional disruption on a global and regional level after prenatal alcohol exposure and indicate suboptimal organization of functional networks. These differences likely underlie sensory dysregulation and behavioral difficulties in prenatal alcohol exposure.
4-uniform permutations with null nonlinearity
Authors: Beierle Christof , Leander Gregor
Published: April 2020

We consider n-bit permutations with differential uniformity of 4 and null nonlinearity. We first show that the inverses of Gold functions have the interesting property that one component can be replaced by a linear function such that it still remains a permutation. This directly yields a construction of 4-uniform permutations with trivial nonlinearity in odd dimension. We further show their existence for all n = 3 and n ≥ 5 based on a construction in Alsalami (Cryptogr. Commun. 10(4): 611–628, 2018). In this context, we also show that 4-uniform 2-1 functions obtained from admissible sequences, as defined by Idrisova in (Cryptogr. Commun. 11(1): 21–39, 2019), exist in every dimension n = 3 and n ≥ 5. Such functions fulfill some necessary properties for being subfunctions of APN permutations. Finally, we use the 4-uniform permutations with null nonlinearity to construct some 4-uniform 2-1 functions from $\mathbb {F}_{2}^{n}$

F

2

n

to $\mathbb {F}_{2}^{n-1}$

F

2

n
−
1

which are not obtained from admissible sequences. This disproves a conjecture raised by Idrisova.
Articulating guilt? The influence of guilt presumption on interviewer and interviewee behaviour
Authors: Adams-Quackenbush Nicole M. , Vrij Aldert , Horselenberg Robert , Satchell Liam P. , van Koppen Peter
Published: April 2020

Research has repeatedly shown that accusatory questions posed during an investigative interview are indicative of biased beliefs about suspect guilt. Linguistic research has shown that the verbs used in utterances can be indicative of biased beliefs about another person. In the present study we examined question type and the verbs used in question formulation using non-police participants to explore the influence of guilt presumption on interview questions. In Study1 we used the Linguistic Category Model (LCM; Semin and Fiedler European Review of Social Psychology, 2, 1–30, 1991) and in Study 2, the Question-Answer Paradigm (QAP; Semin et al. Personality and Social Psychology Bulletin, 21, 834–841, 1995) to analyse verb abstraction and positive/ negative valence of the formulated interview questions. We also explored whether interviewers’ guilt presumptions changed over the course of the interview as well as their motivations for creating the questions they chose to ask (Study 2). We found that participants who presumed guilt were more likely to formulate accusatory questions and use a higher verb abstraction with negative valence (Study 1 and 2). Interviewers asked more questions to gather additional information overall; however, the number of questions was negligible for trying to find support for alternative scenarios or to falsify existing guilt beliefs (Study 2). Interviewers who presumed guilt were also less likely to change their views during the interview and were more likely to report using behavioural cues to solidify their guilt presumptions (Study 2). The overall findings are in line with previous research in both guilt presumptive interviewing and linguistically biased language; however, we expanded on previous research by allowing participants to come to their own conclusions regarding guilt, as well as formulating their own questions for the suspect. Finally, we conclude that there are extensive limitations for using the LCM in applied interview settings and these are discussed.
Real-time RT-PCR detection of Citrus bark cracking viroid (CBCVd) in hops including an mRNA-based internal positive control
Authors: Seigner Luitgardis , Liebrecht Marion , Keckel Linda , Einberger Katharina , Absmeier Carolin
Published: April 2020

Citrus bark cracking viroid (CBCVd), formerly known as pathogen in the genus Citrus and first detected in Slovenian hops in 2014, threatens hop production as it leads to important economic losses. Reduction in yield and quality and even death of the infected plants within a few years are typical observations due to CBCVd infections of hops. The viroid is easily transmitted and spreads rapidly. As it cannot be controlled by plant protection measures, avoiding its introduction into hop gardens and eradicating first centres of infection are of utmost importance. An indispensable prerequisite is a reliable detection method suitable for large-scale routine testing. In this study, the development of primers and probe for real-time RT-PCR for sensitive CBCVd detection is described. To exclude “false negative” results, a nad5 mRNA-based internal positive control was included. To our knowledge, this is the first time such a duplex real-time RT-PCR detection method for CBCVd at least in hops is described. In addition, first method validation data are presented.
Where Spatial Visualization Meets Landscape Research and “Pinballology”: Examples of Landscape Construction in Pinball Games
Authors: Edler Dennis
Published: April 2020

Maps and map-like visualizations in digital games have been repeatedly addressed in research of cartography and related disciplines. For example, visualization techniques and tools used in video and computer games, including navigation and locomotion tools in VR gaming, have been analyzed and adopted to VR-based 3D cartographic modeling in recent time. A successful and diversified game which has only hardly been considered in the literature so far is pinball. Modern pinball machines are equipped with sophisticated map-like playfields (and other related components) that allow pinball players to immerse into a rapidly changing spatial story which is directed by the pinball movement. The (endless) game of skill is cognitively challenging and it sometimes even ‘plays with’ overloading the cognitive capacity of players by activating a multitude of multisensory (spatial) events. An overloaded communication of spatial information is apparently part of the success story of the game. The successful story of pinball also includes several characteristic themes that seem to fascinate the worldwide community of players (and retro fans). These themes, including their map-like visualizations, invite players to be involved into the rapid spatial story, and they include many ‘triggers’ for the individual and social construction of landscapes. These landscapes can fulfill desires for escapism. This article presents characteristic examples of successful and established modern pinball themes and discusses their potentials for landscape construction, from a social constructivist perspective.
Percutaneous endoscopic biliary exploration in complex biliary stone disease: Case series study
Authors: Alotaibi Khalid M. , Alghamdi Hanan M.
Published: April 2020

ABSTRACT

Background and aim:

Patients with complex biliary stone disease are challenging to treat. We present our experience using urological interventions to treat challenging biliary stones.

Methods:

Fifteen patients with biliary calculi underwent 21 interventions using either extracorporeal shock wave lithotripsy (ESWL), percutaneous transhepatic choledochoscopy, percutaneous transcystic choledochoscopy, or a combination of these.

Results:

Most patients were elderly (median age, 60 years). The male-to-female ratio was higher than the norm for biliary stones (1:1.4). The most common reasons for failure of conventional endoscopic retrograde cholangiopancreatography (ERCP) were high American Society of Anesthesia (ASA) score (8 patients 53%), technical failure of ERCP (4 patients, 27%), previous Roux-en-Y gastric bypass (two patients, 13%), and post-common bile duct (CBD) injury with T-tube insertion (one patient, 7%). The stone sites were the CBD, gallbladder, and intrahepatic bile duct in nine (60%), three (20%), and three (20%) patients, respectively. All patients underwent minimally invasive interventions. This included ESWL in seven cases and endoscopic laser lithotripsy and stone manipulation through an access tube in eight patients (transhepatic in four patients, transcholecystic in three patients, and using a T-tube in one patient). Complete stone clearance was achieved in 12 patients (80%), whereas four patients required a second session and one patient required a third. The remaining three patients, two had residual asymptomatic debris and one failed procedure.

Conclusions:

Complicated and high-risk patients with biliary stones could be managed with minimally invasive intervention without subjecting them to a major risky procedure.

Highlights:
The post-operative impact of oversewing stapled anastomoses in colorectal cancer surgery: A retrospective Australian cohort study
Authors: Baqar Ali Riaz , Wilkins Simon , Staples Margaret , Oliva Karen , McMurrick Paul
Published: April 2020

ABSTRACT

Background:

To assess the effect of oversewing double stapled anastomoses (DSA) on clinical outcomes in colorectal cancer surgery, including the rates of anastomotic leak and bleeding.

Materials and methods:

A retrospective analysis of prospectively collected data from two Victorian hospitals was performed on patients having had a colorectal cancer resection between January 2010 and July 2017. Patients with oversewn anastomoses were compared with those patients where no oversewing was performed. Complications (surgical and medical) were investigated using logistic regression. Further subgroup analyses on colonic resections were performed.

Results:

Analysis of the eligible 2001 patients demonstrated that patients with an oversewn DSA were less likely to have an anastomotic leak (p = 0.03), or return to theatre (p = 0.014). An oversewn DSA did not influence in-patient mortality, 30-day mortality or other surgical complications. Univariate analysis showed anastomotic leaks were less likely for oversewn patients and females but more likely with rectal cancers, open surgery or laparoscopic converted to open surgery, and increasing BMI. Subgroup analysis of the 884 colonic resections demonstrated oversewn patients were less likely to return to theatre (OR 0.250, 95%CI 0.070–0.893), have medical complications (OR 0.298, 95%CI 0.106–0.842) or a small bowel obstruction (OR 0.087, 95%CI 0.009–0.820). Univariate analysis showed hybrid or laparoscopic surgery, left side tumours, and a history of arrhythmia increased risk of anastomotic leak for colonic resections. Multivariate analysis showed all these factors had independent associations with anastomotic leak.

Conclusion:

Oversewing a double-stapled anastomoses in colorectal cancer surgery is a protective factor against anastomotic leaks and reduces reoperative surgery rates.

Highlights:
Analysis of Free‐Air Anomalies on the Seaway of the Gulf of Gdańsk: A Case Study
Authors: Pyrchla Krzysztof , Pajak Małgorzata , Pyrchla Jerzy , Idczak Jakub
Published: April 2020

In this paper, we present an attempt to determine the accuracy of shipborne gravimetry for the needs of geoid determination. The shipborne gravity campaign, described in this article, is the beginning of a series of gravimetry measurements in the Polish Exclusive Economy Zone. The campaign was conducted in the area where the accuracy of geoid determination is crucial for the safety of navigation on numerous intersecting ships' routes. The vicinity of the seashore, various depths, and short‐lasting campaign enabled determination of the level of measurement accuracy that can be obtained depending on the conditions. Internal data consistency was estimated as well as an attempt to compute external accuracy. The data were compared with satellite data available for the region. We identified which of the differences are related to the influence of external factors.
MAVEN ROSE Observations of the Response of the Martian Ionosphere to Dust Storms
Authors: Felici M. , Withers P. , Smith M. D. , González‐Galindo F. , Oudrhiri K. , Kahan D.
Published: April 2020

During a Martian dust storm, the lower atmosphere is heated locally. Due to dynamical effects, the upper atmosphere and ionosphere can be lifted upward on a global scale by approximately 10 km. The connections between lower atmospheric dust events and associated ionospheric responses are poorly understood due to limited observations. Here, we present MAVEN Radio Occultation Science Experiment (ROSE) observations of ionospheric peak altitude during dust events in 2018 and 2016. In June 2018, a planet‐encircling dust event arose from the Acidalia storm track in the northern hemisphere. Ionospheric peak altitudes at around 20°S were normal in ROSE egress observations on 19 June and 22 June and then 10–15 km higher on 26 June and thereafter. Ionospheric peak altitudes at around 50°N were also elevated in ROSE ingress observations, which began on 17 June. This suggests that the ionospheric peak altitude was affected by the dust event in the northern hemisphere before the southern hemisphere. We also observe evidence that smaller dust storms can trigger ionospheric responses: In July–October 2016, ionospheric peak altitudes at solar zenith angles of 54–70° and latitudes of 50–80°S were 20 km higher than expected. These observations were acquired during a modest “A storm” during a year without a global dust storm.
A three-dimensional cuprous lead bromide framework with highly efficient and stable thermochromic luminescence properties
Authors: Jing Chang-Qing , Wu Jia-Hang , Cao Yao-Yao , Che Hang-Xin , Zhao Xian-Mei , Yue Meng , Liao Yuan-Yuan , Yue Cheng-Yang , Lei Xiao-Wu
Published: April 2020

The first 3D bimetallic halide of [H2DABCO]2Cu6PbBr12 based on two types of 6-connected nodes displays highly efficient thermochromic luminescence from broadband yellow to green light emissions.
Materials engineering, processing, and device application of hydrogel nanocomposites
Authors: Cha Gi Doo , Lee Wang Hee , Lim Chanhyuk , Choi Moon Kee , Kim Dae-Hyeong
Published: April 2020

The integration of patterning technologies and functional hydrogel nanocomposites enables their advanced device applications such as sensors, actuators, energy devices, and tissue engineering scaffolds.
Predictive function control in tertiary level for power flow management of DC microgrid clusters
Authors: Liu Sucheng , Liu Rui , Zheng Jiazhu , Liu Xiaodong
Published: April 2020

Tertiary control is the highest level in hierarchical control of microgrids to perform power exchange between the microgrid and external networks. In this Letter, a tertiary control strategy based on predictive function control (PFC) is proposed to manage power flow in DC microgrid (DCMG) clusters. Unlike linear PI control suitable for single‐input and single‐output systems, the PFC strategy is a nonlinear control method and capable of multiple input and multiple output control tasks with multiple objectives optimisation on‐line. By solving the cost function in the finite receding horizon, voltage set points are computed in real‐time to create bus voltage difference for power transfer between interconnected DCMGs. The PFC‐based tertiary control for the DCMG cluster is verified through simulations.
Selected and refined local attention module for object detection
Authors: Luo Xiaofan , Hu Haifeng
Published: April 2020

Lacking enough feature expression on the shallow part of the network always hinders the object detection results by missing the position of small instances. To address this, the authors propose a selected and refined local attention module (SRLAM) for object detection. SRLAM tries to improve the feature expression of local areas by establishing a relationship graph between different channels. Inspired by the classical non‐local neural networks for video classification, they present the local attention module (LAM) to more effectively use remote information. The LAM can suppress the influence of irrelevant areas for improving detection accuracy. Moreover, for further information utilisation, the weight map generated by LAM is integrated together with the original feature map and the information from the higher layer by a feature fused module. Experiments on the PASCAL VOC2007 show that the authors’ model has good detection performance, the proposed model can achieve 81.6 mAP when the size of the input image is 300 × 300, that outperforms many other mainstream detectors.
Clustering based two‐stage blind channel estimation for special QPSK transmission
Authors: Yao Rugui , Zhang Yuan , Wu Qihong , Xu Juan
Published: April 2020

Special QPSK has been demonstrated to have superiority of spectral efficiency. However, due to its scatter of constellations and no pilots inserted, the channel estimation is a challenge. In this Letter, clustering based two‐stage blind channel estimation is proposed for special QPSK transmission. For the scheme, k‐means clustering is applied to reduce the complexity and improve the accuracy of channel estimation in the first stage, while frame synchronisation helps to confirm the estimated result. Simulation results show that this scheme presents small mean square error and good BER performance. Furthermore, this scheme can implement frame synchronisation and channel estimation simultaneously.
Compact wide‐stopband SIW dual‐band filter with closely spaced passbands
Authors: Xie Hao‐Wei , Zhou Kang , Zhou Chun‐Xia , Wu Wen
Published: April 2020

Compact substrate‐integrated waveguide (SIW) dual‐band bandpass filter with closely spaced passbands and wide‐stopband characteristics is proposed for the first time based on inline‐coupled perturbed SIW triple‐mode cavities. The first three resonant modes in the triple‐mode cavities can be flexibly controlled so that two closely spaced passbands can be realised based on the first two resonant modes, and wide‐stopband can be achieved by staggering the third and other higher‐order resonant modes without resorting to extra structures. The external and internal couplings of the dual passbands can be specified and designed flexibly benefitting from the offset feeding ports and coupling windows. A prototype centred at 13 and 14 GHz is synthesised, designed, fabricated, and tested as a demonstration, extending the stopband to 1.97f1 with rejection level better than 25 dB.
FHCS: Hybridised optimisation for virtual machine migration and task scheduling in cloud data center
Authors: Balaji Naik Banavath , Singh Dhananjay , Samaddar Arun B.
Published: April 2020

Cloud computing and virtualisation are recent approaches to develop minimum energy usage in virtualised cloud data centre (DC) for resource management. One of the major problems faced by cloud DCs is energy consumption which increases the cost of cloud user and environmental influence. Therefore, virtual machine (VM) consolidation is properly proposed in many approaches which reallocate the VMs by VM migration with the objective of minimum energy consumption. Here, VM consolidation based on the Fruit fly Hybridised Cuckoo Search (FHCS) algorithm is proposed to obtain the optimal solution with the help of two objective functions in cloud DC. This FHCS approach efficiently minimises the energy usage and resource depletion in cloud DC. The proposed work comparison is done with Ant Colony System (ACS), Particle Swarm Optimisation (PSO) algorithm and Genetic Algorithm (GA). The simulation conclusion reveals the advantage of the FHCS and VM migration method over existing procedures such as GA, PSO and ACS in terms of energy consumption and resource utilisation. The proposed method achieves 68 Kwh less energy and 72% less resources than existing methods. Simulation results have shown that energy consumption of the proposed method is reduced with less number of active PMs than other conventional approaches.
Efficient design optimisation for UAV‐enabled mobile edge computing in cognitive radio networks
Authors: Pan Yu , Da Xinyu , Hu Hang , Ni Lei , Xu Ruiyang , Zhang Hongwei
Published: April 2020

Mobile edge computing (MEC) has been envisaged as a promising technique in fifth generation (5G) and beyond wireless networks. In order to alleviate the explosive growth of computation and spectrum demand, cognitive radio (CR) and unmanned aerial vehicles (UAV) are studied in MEC‐aware networks. In this study, considering a local computation and partial offloading scheme, a UAV‐enabled CR‐MEC framework is proposed and the authors' aim is to maximise the energy efficiency (EE) of the wireless devices (WDs). The formulated optimisation problem is not convex and challenging to be solved. To deal with it, an equivalent reformulation of this EE maximisation problem is introduced, and the authors decompose the original problem into two sub‐problems, wherein the sub‐problems become tractable and can be solved by jointly optimising sensing time, offloading power and WD‐UAV scheduling. Numerical results highlight the EE enhancement with various system parameters and reveal the superiority of the proposed algorithm than other schemes with low computational complexity.
Integral reinforcement learning solutions for a synchronisation system with constrained policies
Authors: Abouheaf Mohammed , Mahmoud Magdi S. , Gueaieb Wail
Published: April 2020

A class of the differential games is considered where the agents employ constrained control strategies, and the mutual interactions between the agents are restricted by an undirected graph topology. The dynamical behaviour of the agents and the applied control policies are evaluated using local non‐linear performance indices. The solution of the differential game is obtained via a game‐theoretic mathematical framework based on adaptive integral reinforcement learning (IRL) schemes. The constrained optimality conditions for the graphical game are found using Bellman's optimality principles. It is demonstrated that, solving the game's coupled IRL‐Bellman optimality equations with constrained control policies yields a Nash equilibrium solution. Online adaptive learning solutions are developed using value iteration processes and means of the adaptive critics. Neural network structures are adopted to approximate the constrained optimal control strategies and the respective optimal value functions for each agent in a distributed fashion. The robustness of the proposed solutions is tested using uncertain dynamical learning environment and graph with large time‐varying deviations in the connectivity weights.
Functional observers design for positive systems with delays and unknown inputs
Authors: Arogbonlo Adetokunbo , Huynh Van Thanh , Oo Amanullah Maung Than , Trinh Hieu
Published: April 2020

This study addresses the problem of synthesising functional observers for positive time‐delay systems subjected to unknown inputs. A functional observer architecture for the problem is presented. The existence conditions of the observer and a linear programming problem characterising the existence conditions of such a functional observer are also established. An algorithm for designing the observer is presented. Finally, examples are given to showcase the effectiveness of the observer.
Distributed leaderless synchronisation control for non‐linear MASs with both parameter and non‐parameter uncertainty terms
Authors: Li Shan , Ma Hongbin
Published: April 2020

In this study, the authors first discuss the adaptive synchronisation control for discrete‐time non‐linear multi‐agent systems (MASs) with parameter and non‐parameter uncertainty terms under leaderless strongly connected digraph, which has not been mentioned in the existing literature. To cope with these two kinds of uncertainties, a state variable is used as an auxiliary tool to compensate for the non‐parameter uncertainties, meanwhile, a new dead zone is constructed to ensure the boundedness of the estimated values of the unknown parameters. Based on the local information within the neighbourhood, distributed adaptive synchronisation protocols are designed. Moreover, they strictly prove that the designed adaptive control protocols can harmonise all agents' dynamics to achieve their synchronisation in theory. At the end of this study, an example is provided to indicate the validness of the proposed control protocols.
Torque ripple reduction of switched reluctance motor by optimising switch angle based on analytical modelling
Authors: Shuguang Zuo , Mingtian Liu , Shenglong Hu , Hao Wu
Published: April 2020

To reveal the torque ripple mechanism of switched reluctance motors (SRMs), an analytical instantaneous torque model considering current harmonics is established based on the analysis of the air‐gap magnetic field. The results show that torque ripple contains third‐order harmonic components in a three‐phase SRM and mainly comes from the current harmonic, the rotor slotting, and their interaction. Then, the influence of main current harmonics on the torque ripple is investigated based on an analytical calculation method and it is found that the filtering of the second‐order current harmonic is more conducive to reducing the torque ripple. Finally, the influence of the turn‐on/turn‐off angle on each harmonic current is fully analysed by means of the analytical modelling of current, based on which the second‐order current harmonic and torque ripple is reduced by optimising the turn‐on/turn‐off angle. Also, it is found that the suitable prior turn‐on angle and delayed turn‐off angle is helpful to reduce the torque ripple.
Convergence and accuracy of near‐field‐corrected iterative physical optics for scattering by imperfectly conducting and dielectric objects
Authors: Rim Jae‐Won , Koh Il‐Suek
Published: April 2020

This communication investigates the convergence behaviour and accuracy of a near‐field corrected iterative physical optics scheme for scatterings by imperfectly conducting and dielectric objects. The scatterings by large and complex impedance surface bodies such as fixed wing aircraft, rotatory wing aircraft, tank, vessel, and boat are computed and compared with those of a full‐wave method. Several RF characteristics of a Von‐Karman radome are also analysed and compared as a wave penetration application. Based on these comparisons, the near‐field correction effect is examined on the accuracy of the iterative physical optics scheme.
Circularly‐polarised end‐fire antenna and arrays for 5G millimetre‐wave beam‐steering systems
Authors: Al‐Amoodi Khaled , Honari Mohammad Mahdi , Mirzavand Rashid , Melzer Jordan , Elliott Duncan G. , Mousavi Pedram
Published: April 2020

This study presents a circularly‐polarised substrate‐integrated waveguide end‐fire antenna and four‐antenna arrays for 5G beam‐steering mobile devices at 28 GHz. Polarisation is achieved through implementation of a substrate‐integrated waveguide notched‐septum polariser. It is then loaded with a dielectric lens to improve gain, axial ratio bandwidth, and circular polarisation (CP) purity. To suppress the mutual coupling between array elements, vias are extended on either side of the lens. It also improves the single‐element axial ratio and front‐to‐back ratio. The antenna's performance is found to be resilient to typical manufacturing tolerances for the lens and via extensions. The element and arrays are manufactured and measured. The prototypes demonstrated an impedance bandwidth of 11.4% with a maximum array gain of 10.5 dBi and a steering range of up to (with reduced performance when steered to ). Within this range, the antenna array demonstrates a gain variation of up to 3 dB and very good CP purity within the radiation half‐power beamwidths (HPBWs). A wide single‐element elevation HPBW of is also demonstrated. Given its performance and ease of manufacture in a printed circuit board process, the proposed antenna could be a strong candidate for 5G millimetre‐wave beam‐steering systems.
Improving the accuracy of permanent magnet rotor position estimation for stepper motors using magnetic induction and harmonic rejection
Authors: Tran Ngoc Hoang , Nguyen Ty Trung , Cao Hung Quang , Le Kien Minh , Jeon Jae Wook
Published: April 2020

To improve the accuracy of permanent magnet (PM) rotor position estimation for a hybrid stepper motor (HSM), the authors propose a sensorless control design based on the back electromagnetic force (back‐EMF) caused by magnetic induction and harmonic rejection via an orthogonal third‐order phase‐locked loop (PLL3rd) and an integral harmonic filter (IHF). The accuracy of estimation is analysed considering PM rotor position estimation errors. The harmonics of the back‐EMF signal are eliminated by the IHF before entering the PLL3rd, which synchronises and decreases position estimation error. This technique is a simple, reliable, and effective method for implementing sensorless control of an HSM. An industrial test‐bench was used to implement the proposed scheme. The experimental results are presented to validate the effectiveness of the proposed estimation method.
Three‐phase quasi‐Z source inverters with regulated multiple AC outputs for microgrid applications and three‐phase residential load
Authors: Sonkar Shri Prakash , Lal Vivek Nandan , Singh Rajeev Kumar
Published: April 2020

In this study, two 3‐φ quasi‐Z source inverters (qZSIs) with multiple ac outputs are proposed. The proposed topologies are developed from qZSI to obtain parallel mode and series mode 3‐φ multi‐output inverters. In parallel mode, the topology yields n‐number of parallel ac outputs with different voltages and currents for different load conditions. For series mode, topology yields n‐number of series ac outputs with same voltages and same load currents. Unlike voltage source derived multi‐output inverters, the proposed inverters have all inherent properties of qZSI, like shoot‐through protection and both buck–boost operations. For generating switching signals in these inverters, sinusoidal pulse width modulation with constant frequency shoot‐through scheme is used. The proposed topologies fulfil more than one load demand at a time without any extra adaptor or regulator. The proposed inverters can be used for simultaneous multiple dc/ac power conversion for three‐phase microgrid applications and three‐phase residential loads. In this work, the proposed topologies with closed‐loop control have been implemented for two inverter units, which is capable of supplying two ac outputs simultaneously. The mathematical modelling of the proposed topologies is carried out for performance analysis. The experimental results of 240 W lab prototypes have been presented to validate the proposed three‐phase multi‐output qZSIs.
Five‐level one‐capacitor boost multilevel inverter
Authors: Abdel‐Rahim Omar , Wang Haoyu
Published: April 2020

Multilevel inverter configurations are a suitable candidate for medium and high power applications. This study presents a new one‐capacitor‐based five‐level (2Vdc, Vdc, 0, −Vdc, − 2Vdc) boost multilevel inverter. The single‐phase version of the proposed formation has one dc‐source, eight switches and one capacitor. To provide boosting ability, the inverter is operating based on charge‐pump theory, where the capacitor is charging in parallel and discharging in series connections to provide a higher output voltage. The proposed configuration requires simple control tasks, and for this purpose, level‐shift pulse width modulation strategy, where the reference signal is compared with four carriers, is implemented to drive the switches and generates the required pulses pattern. The developed inverter has some distinct features like the usage of only one dc‐source and one‐capacitor, compact size, simple control requirements and boosting ability. The system is simulated with MATLAB/Simulink and a hardware prototype is developed to verify the performance of the developed five‐level configuration. The results show that the developed five‐level multilevel inverter reaches the expected performance
Performance analysis of linear precoders with imperfect channel covariance information for multicell system
Authors: Mukubwa Emmanuel , Sokoya Oludare A.
Published: April 2020

Comparison and analysis of the regularised zero forcing precoder, rapid numerical algorithms‐based precoder and the truncated polynomial expansion‐based precoder are done for massive multiple‐input multiple‐output wireless system for multicell scenario. The analysis was done for the imperfect channel covariance information. The achievable signal‐to‐interference‐and‐noise ratio, spectral efficiency and energy efficiency were investigated. The simulated outcome of the rapid numerical algorithms, regularised zero forcing and truncated polynomial expansion precoders for multicell massive MIMO system was analysed. The rapid numerical algorithms‐based precoder gave the best performance followed by the regularised zero forcing precoder, and the truncated polynomial expansion‐based precoder had the lowest performance for the multicell massive MIMO system. The increase in spectral efficiency per cell can be attributed to the fact that the pre‐log factor reduces with the increased number of pilots. Also, this leads to increased instantaneous signal‐to‐interference‐and‐noise ratio as the channel estimates become better with reduced pilot contamination. Again, for truncated polynomial expansion precoding there is a reduction in spectral efficiency because improvement in approximation quality do not overshadow the reduction in pre‐log factor. The performance is evaluated for uncoordinated and coordinated massive MIMO.
Combination of magnetic solid‐phase extraction with dispersive liquid–liquid microextraction followed by GC‐MS for trace analysis of synthetic cannabinoids in plasma samples
Authors: Shokoohi Rad Samad , Dalali Naser , Baheri Tahmineh
Published: April 2020

In this work, an efficient extraction method based on a combination of magnetic solid‐phase extraction (MSPE) and dispersive liquid–liquid microextraction (DLLME) followed by GC‐MS was developed for the determination of 5F‐ADB‐PINACA (ADB) and AB‐FUBINACA (AB). Fe3O4 nanoparticles coated with poly ortho‐aminophenol were synthesised and applied as the sorbent. Extraction parameters including pH in both the MSPE (pH 3.5) and DLLME (pH 11) steps, sorbent amount (20 mg), salt effect (10%, w/v), adsorption (20 min) and desorption time (5 min), type and volume of eluent (1.0 ml of acetone) and extraction solvent (25 µl of toluene), were optimised. Enrichment factors of 213 and 437 obtained for ADB and AB, respectively. The linear ranges of the method were obtained 0.2–50 and 0.2–50 ng ml−1 for ADB and AB, respectively. Regression coefficients above 0.998 and LODs of 0.01 and 0.005 ng ml−1 resulted. The intra‐ and inter‐day RSDs% (n = 3) were found to be 8.3 and 7.6%, respectively. Finally, MSPE‐DLLME‐GC/MS was applied for the determination of analytes in plasma samples. Recoveries were within the range of 87.6–102.6 and 89.4–104% for the ADB and AB, respectively, indicating the suitability of the proposed method for analysis of ADB and AB in complicated matrices.