bluuebunny/crossref_metadata_2025 huggingface dataset:
Report of the Nomenclature Committee for Algae: 20
Authors: Andersen Robert A.
Published: August 2019

The nonhyphenated name Pseudonitzschia is not recommended for conservation against the name Pseudo‐nitzschia. The generic name Haplocladium (Müll. Hal.) Müll. Hal. (Bryophyta) is not recommended for conservation against “Haplocladium Nägeli” (Rhodophyceae), because the latter is considered to have been validly published only as Pterothamnion subg. Haplocladium. The proposal to conserve the name Cribrosphaerella against Cribrosphaera became unnecessary due to changes made in the Shenzhen Code.
Molecular and morphological data reveal three new tribes within the Scirpo‐Caricoid Clade (Cyperoideae, Cyperaceae)
Authors: Léveillé‐Bourret Étienne , Starr Julian R.
Published: August 2019

The circumscription of the circumboreal tribe Scirpeae has been contentious since the earliest infrafamilial classifications of the Cyperaceae (>100 genera, ~ 5500 species). Molecular phylogenetic studies place Scirpeae in a strongly supported clade with the enigmatic genusKhaosokiaand tribes Cariceae, Dulichieae, and Sumatroscirpeae, a lineage comprising more than 40% of all Cyperaceae species. This lineage was previously known as the Cariceae‐Dulichieae‐Scirpeae (CDS) clade. Here we informally characterize it as the “Scirpo‐Caricoid Clade”. Previous phylogenetic and phylogenomic studies of the Scirpo‐Caricoid Clade have shown Scirpeae to be paraphyletic, forming four distinct lineages that are successive sisters to a Cariceae + ​Sumatroscirpeae clade, thus confirming decade‐old suspicions that the modern circumscription of Scirpeae is unnatural. Using a total‐evidence phylogenetic analysis incorporating three plastid markers (matK,ndhF,rps16), two nuclear ribosomal markers (ETS‐1f, ITS), and 64 morphological characters, this study confirms the paraphyly of Scirpeae, the isolated phylogenetic position ofKhaosokia, and identifies morphological synapomorphies for seven monophyletic lineages that are here recognized as tribes. Our new classification places for the first time all genera of the Scirpo‐Caricoid Clade into natural tribes that are identifiable using morphological and embryological characters. Three new tribes are proposed: Calliscirpeae tr. nov., Khaosokieae tr. nov. and Trichophoreae tr. nov. Diagnoses for all tribes of the Scirpo‐Caricoid Clade, an identification key to all currently recognized Cyperaceae tribes, and identification keys for all genera of the Scirpo‐Caricoid Clade are provided.
Evaluating Agency in Literacy Using the Student Agency Profile
Authors: Vaughn Margaret , Premo Joshua , Sotirovska Vera V. , Erickson Danielle
Published: August 2019

Student agency is an important dimension of classroom literacy learning. Recent calls have emphasized the need to support student agency in literacy. Despite this interest, the field lacks a viable instrument that can be used to measure student agency with elementary students. The authors share the Student Agency Profile, a survey instrument that can measure student agency in literacy contexts. The authors provide insight into the validation process, which included 1,794 elementary students, and direction on how to administer, score, and interpret results. A central aim is to show how the survey can be used in practice while supporting teachers in their efforts to cultivate student agency in today's diverse classrooms.
Using Theatre to Develop Writing Skills: The Story Pirates Idea Storm
Authors: Mayes Amanda S. , Coppola Elizabeth C. , Fa Bingxin
Published: August 2019

The authors explored the impact of a novel, interactive performing arts–based program on students’ writing skills. The program featured the Story Pirates, a group that teaches children how to write stories and then turns their stories into a musical sketch comedy show. Written stories from the third‐grade students in an elementary school were collected before and after the Story Pirates program and then compared to determine the impact of the program on students’ writing skills. The percentage of students incorporating key elements of writing—settings, main characters, additional characters, and motives—increased substantially after their participation in the Story Pirates program. These findings suggest that theatre‐based interventions may strengthen elementary students’ writing skills.
Dark radiation and superheavy dark matter from black hole domination
Authors: Hooper Dan , Krnjaic Gordan , McDermott Samuel D.
Published: August 2019

Abstract

If even a relatively small number of black holes were created in the early universe, they will constitute an increasingly large fraction of the total energy density as space expands. It is thus well-motivated to consider scenarios in which the early universe included an era in which primordial black holes dominated the total energy density. Within this context, we consider Hawking radiation as a mechanism to produce both dark radiation and dark matter. If the early universe included a black hole dominated era, we find that Hawking radiation will produce dark radiation at a level ΔN
eff ∼ 0.03 − 0.2 for each light and decoupled species of spin 0, 1/2, or 1. This range is well suited to relax the tension between late and early-time Hubble determinations, and is within the reach of upcoming CMB experiments. The dark matter could also originate as Hawking radiation in a black hole dominated early universe, although such dark matter candidates must be very heavy (m
DM ≳ 1011 GeV) if they are to avoid exceeding the measured abundance.
Electroweak baryogenesis from temperature-varying couplings
Authors: Ellis Sebastian A. R. , Ipek Seyda , White Graham
Published: August 2019

Abstract

The fundamental couplings of the Standard Model are known to vary as a function of energy scale through the Renormalisation Group (RG), and have been measured at the electroweak scale at colliders. However, the variation of the couplings as a function of temperature need not be the same, raising the possibility that couplings in the early universe were not at the values predicted by RG evolution. We study how such temperature-variance of fundamental gauge couplings can aid the production of a baryon asymmetry in the universe through electroweak baryogenesis. We do so in the context of the Standard Model augmented by higher-dimensional operators up to dimension 6.
Searching for BSM neutrino interactions in dark matter detectors
Authors: Link Jonathan M. , Xu Xun-Jie
Published: August 2019

Abstract

Neutrino interactions beyond the Standard Model (BSM) are theoretically well motivated and have an important impact on the future precision measurement of neutrino oscillation. In this work, we study the sensitivity of a multi-ton-scale liquid Xenon dark matter detector equipped with an intense radioactive neutrino source to various BSM neutrino-electron interactions. We consider the conventional Non-Standard Interactions (NSIs), other more generalized four-fermion interactions including scalar and tensor forms, and light-boson mediated interactions. The work shows that with realistic experimental setups, one can achieve unprecedented sensitivity to these BSM neutrino-electron interactions.
Supersymmetric indices of 3d S-fold SCFTs
Authors: Garozzo Ivan , Monaco Gabriele Lo , Mekareeya Noppadol , Sacchi Matteo
Published: August 2019

Abstract

Enhancement of global symmetry and supersymmetry in the infrared is one of the most intriguing phenomena in quantum field theory. We investigate such phenomena in a large class of three dimensional superconformal field theories, known as the S-fold SCFTs. Supersymmetric indices are computed for a number of theories containing small rank gauge groups. It is found that indices of several models exhibit enhancement of supersymmetry at the superconformal fixed point in the infrared. Dualities between S-fold theories that have different quiver descriptions are also analysed. We explore a new class of theories with a discrete global symmetry, whose gauge symmetry in the quiver has a different global structure from those that have been studied earlier.
Jet substructure measurements of interference in non-interfering SMEFT effects
Authors: Aoude Rafael , Shepherd William
Published: August 2019

Abstract

The tails of diboson production at the LHC are sensitive to the interference between Standard Model and higher dimension operators parameterizing the effects of heavy new physics. However, helicity selection rules for the diboson scattering amplitudes set an obstruction to the na¨ıve interference contributions of dimension six operators, causing the total diboson rate correction’s leading contribution to cancel. In this case, carefully measuring the azimuthal decay angles “resurrects” the interference, recouping sensitivity to the “non-interfering” operators. We explore these signatures in detail, and find that the EFT uncertainties associated with higher-dimensional operators are uniquely well-suppressed by the construction of an asymmetry variable which is only generated by these non-interfering operators, relegating the effects of higher-dimensional, interfering operators to the same status as statistical errors in this observable. We perform a complete analysis of this azimuthal interference pattern in hadronic decays of W bosons using jet substructure techniques to tag the bosons and measure their azimuthal decay angles. This technique provides a valuable cross-check to purely-leptonic measurements of interference resurrection in diboson production.
Rényi entropy at large energy density in 2D CFT
Authors: Guo Wu-zhong , Lin Feng-Li , Zhang Jiaju
Published: August 2019

Abstract

We investigate the Rényi entropy and entanglement entropy of an interval with an arbitrary length in the canonical ensemble, microcanonical ensemble and primary excited states at large energy density in the thermodynamic limit of a two-dimensional large central charge c conformal field theory. As a generalization of the recent work [17], the main purpose of the paper is to see whether one can distinguish these various large energy density states by the Rényi entropies of an interval at different size scales, namely, short, medium and long. Collecting earlier results and performing new calculations in order to compare with and fill gaps in the literature, we give a more complete and detailed analysis of the problem. Especially, we find some corrections to the recent results for the holographic Rényi entropy of a medium size interval, which enlarge the validity region of the results. Based on the Rényi entropies of the three interval scales, we find that Rényi entropy cannot distinguish the canonical and microcanonical ensemble states for a short interval, but can do the job for both medium and long intervals. At the leading order of large c the entanglement entropy cannot distinguish the canonical and microcanonical ensemble states for all interval lengths, but the difference of entanglement entropy for a long interval between the two states would appear with 1/c corrections. We also discuss Rényi entropy and entanglement entropy differences between the thermal states and primary excited state. Overall, our work provide an up-to-date picture of distinguishing different thermal or primary states at various length scales of the subsystem.
Quantum epidemiology: operator growth, thermal effects, and SYK
Authors: Qi Xiao-Liang , Streicher Alexandre
Published: August 2019

Abstract

In many-body chaotic systems, the size of an operator generically grows in Heisenberg evolution, which can be measured by certain out-of-time-ordered four-point functions. However, these only provide a coarse probe of the full underlying operator growth structure. In this article we develop a methodology to derive the full growth structure of fermionic systems, that also naturally introduces the effect of finite temperature. We then apply our methodology to the SYK model, which features all-to-allq-body interactions. We derive the full operator growth structure in the largeqlimit at all temperatures. We see that its temperature dependence has a remarkably simple form consistent with the slowing down of scrambling as temperature is decreased. Furthermore, our finite-temperature scrambling results can be modeled by a modified epidemic model, where the thermal state serves as a vaccinated population, thereby slowing the overall rate of infection.
Experimental evaluation of partially hydrolyzed polyacrylamide and silica nanoparticles solutions for enhanced oil recovery
Authors: Yadav Upendra Singh , Kumar Harinandan , Roy Vishnu , Juyal Saurabh , Tripathi Anurag , Shanker Anveshika
Published: August 2019

The establishment of oil production well is becoming a challenge with the increasing demand for energy. The fulfillment of energy need requires large production of oil and gas as it is a primary source of energy. EOR is also important because of the enhancement in oil production from thirty percent to more than fifty percent. The chemical EOR is one of the techniques for the increment in oil production. Chemical flooding using water-soluble polymers like partially hydrolyzed polyacrylamide (PHPA) has been industrially used as an EOR technique. The paper deals with the effect of nano-silica particles on viscosity as well as the shear rate of the polymer solution. The change in viscosity, as well as shear rate, was studied at variable concentrations of the nano particles in the different concentrations of PHPA solution. Mutual correlation between viscosity and other parameters like temperature, shear rate, salinity, nanoparticle concentration, and polymer concentration was established using the statistical method.
The potential of coffee stems gasification to provide bioenergy for coffee farms: a case study in the Colombian coffee sector
Authors: Garcia-Freites Samira , Welfle Andrew , Lea-Langton Amanda , Gilbert Paul , Thornley Patricia
Published: August 2019

The coffee industry constitutes an important part of the global economy. Developing countries produce over 90% of world coffee production, generating incomes for around 25 million smallholder farmers. The scale of this industry poses a challenge with the generation of residues along with the coffee cultivation and processing chain. Coffee stems, obtained after pruning of coffee trees, are one of those abundant and untapped resources in the coffee supply chain. Their high lignocellulosic content, the low calorific value ranging between 17.5 and 18 MJ kg−1 and the low ash content make them a suitable solid fuel for thermochemical conversion, such as gasification. This research evaluates the feasibility of using these residues in small-scale downdraft gasifiers coupled to internal combustion engines for power and low-grade heat generation, using process modelling and the Colombian coffee sector as a case study. The producer gas properties (5.6 MJ Nm−3) and the gasifier’s performance characteristics suggest that this gas could be utilized for power generation. A cogeneration system efficiency of 45.6% could be attainable when the system’s low-grade heat is recovered for external applications, like in the coffee drying stage. An analysis of the energy demand and coffee stems availability within the Colombian coffee sector shows that the biomass production level in medium- to large-scale coffee farms is well matched to their energy demands, offering particularly attractive opportunities to deploy this bioenergy system. This work assesses the feasibility of providing coffee stem–sourced low-carbon energy for global coffee production at relevant operating scales in rural areas.
Rational Design of Layered SnS2 on Ultralight Graphene Fiber Fabrics as Binder-Free Anodes for Enhanced Practical Capacity of Sodium-Ion Batteries
Authors: Ren Zongling , Wen Jie , Liu Wei , Jiang Xiaoping , Dong Yanheng , Guo Xiaolong , Zhao Qiannan , Ji Guipeng , Wang Ronghua , Hu Ning , Qu Baihua , Xu Chaohe
Published: August 2019

Generally, the practical capacity of an electrode should include the weight of non-active components such as current collector, polymer binder, and conductive additives, which were as high as 70 wt% in current reported works, seriously limiting the practical capacity. This work pioneered the usage of ultralight reduced graphene fiber (rGF) fabrics as conductive scaffolds, aiming to reduce the weight of non-active components and enhance the practical capacity. Ultrathin SnS2 nanosheets/rGF hybrids were prepared and used as binder-free electrodes of sodium-ion batteries (SIBs). The interfused graphene fibers endow the electrode a porous, continuous, and conductive network. The in situ phase transformation from SnO2 to SnS2 could preserve the strong interfacial interactions between SnS2 and graphene. Benefitting from these, the designed binder-free electrode delivers a high specific capacity of 500 mAh g−1 after 500 cycles at a current rate of 0.5 A g−1 with almost 100% Coulombic efficiency. Furthermore, the weight percentage of SnS2 in the whole electrode could reach up to 67.2 wt%, much higher than that of common electrode configurations using Cu foil, Al foil, or carbon cloth, significantly highlighting the ultralight characters and advantages of the rGF fabrics for using as binder-free electrodes of SIBs.
Developing agency in the transition to self‐management of cystic fibrosis in young people
Authors: Cronly Jennifer , Savage Eileen
Published: August 2019

Introduction

Young people living with a chronic illness must be supported by healthcare professionals and parents to manage their care as they move through adolescence and into adulthood. The concept of agency is relevant to this process as it involves reflecting on one's behaviour and its consequences, and considering alternative possibilities, before committing to a course of action.

Methods

The aim of this study was to explore the role of agency in young people's transition to self‐management of cystic fibrosis. Qualitative semi‐structured interviews were carried out with 13 young people (7 female, 6 male) aged 13‐22 years, recruited from three cystic fibrosis clinics in the Republic of Ireland.

Results

By self‐monitoring their behaviour and managing their symptoms the young people described a process by which they employed agency and as a result, gained confidence and a sense of control over their illness. Although, parents and health care professionals aided in the development of agency, the young people explained that it was occasionally threatened, particularly in their interactions with health care professionals. This led the young person to react defensively, and negatively affected their relationship with health care professionals.

Conclusions

For young people to feel supported empowered in the management of their illness, their developing ability to exercise agency must be respected and encouraged through collaborative decision making.
Lost in transition, found in recession? Satisfaction with democracy in Central Europe before and after economic crises
Authors: Vlachová Kláara
Published: August 2019

For decades, research on democracy has produced evidence that the peoples of countries in Central Europe are less satisfied with the way democracy works in their countries than people in Western Europe. Using the data from the European Social Survey (ESS) I explore, how satisfaction with the way democracy works (SWD) changed in these countries between 2004 and 2014 and test the impact of satisfaction with the present state of the economy and trust in parliament on SWD. Results of the analysis reveal that people in Central Europe are still less satisfied with the democratic performance on average than people in Western Europe, but their satisfaction is on the rise especially in countries where the economy performs well, economic performance brings better standard of living, and people share a sense of economic optimism. Results also suggest that in countries where economic optimism is low, political evaluations of “crises in democracy” may play a larger role in explaining satisfaction with democratic performance.
Information Theory for Model Diagnostics: Structural Error is Indicated by Trade‐Off Between Functional and Predictive Performance
Authors: Ruddell Benjamin L. , Drewry Darren T. , Nearing Grey S.
Published: August 2019

Because of the possibility of getting the right answers for the wrong reasons, the predictive performance of a complex systems model is not by itself a reliable indicator of hypothesis quality for the purposes of scientific learning about processes. The predictive performance of a structurally adequate model should be an emergent property of its functional performance. In this context, any Pareto trade‐off between measures of predictive performance versus functional performance indicates process‐level error in the model; this trade‐off, if it exists, indicates that the model's predictions are right for the wrong functional reasons. This paper demonstrates a novel concept based on information theory that is capable of attributing observed errors to specific processes. To demonstrate that the concept and method hold true for models and observations of real systems, we employ a minimal single‐parameter‐variation sensitivity analysis using a sophisticated ecohydrology model, MLCan, for a well‐monitored field site (Bondville IL Ameriflux Soybean). We identify both functional and predictive error in MLCan, and also evidence of the hypothesized tradeoffs between the two. This trade‐off indicates structural error within MLCan. For example, the sensible heat flux process can be calibrated to achieve good predictive performance at the cost of poor functional performance. In contrast, we find little structural error for processes driven by solar radiation, which appear “right for the right reasons.” This method could be applied broadly to pinpoint process error and structural error in a wide range of system models, beyond the ecohydrological scope demonstrated here.
A Nearly 100-Year-Old Physics Model Replicates Modern Arctic Ice Melt
Authors: Crowell Rachel
Published: August 2019

The model was previously used to describe the behavior of ferromagnets in the presence of external magnetic fields.
The Flickering Sky Islands
Authors: Joel Lucas
Published: August 2019

In the Andes, islands in the sky flicker, and evolution kicks into high gear.
Capturing Snowmelt Patterns from Cloudy Satellite Images
Authors: Stanley Sarah
Published: August 2019

A new modeling strategy could improve streamflow predictions in places where mountain snow is a critical source of water.
The Value of Early-Career Mentoring Through AGU
Authors: Roche Kevin , Marshall Anita , Paiewonsky Pablo , Yan Jing , Brenner Logan , Saia Sheila
Published: August 2019

The first groups of young and experienced scientists matched by AGU’s new mentoring program gave it high marks.
Australia’s Complex Intertidal Zones Mapped in 3-D
Authors: Cartier Kimberly
Published: August 2019

Intertidal zones support biodiverse habitats but have lost serious ground in recent decades to development, erosion, and sea level rise.
Forum Explores Motivating Different People About Climate Change
Authors: Showstack Randy
Published: August 2019

Experts say that most people think that climate change is happening, but they have differing thoughts about the causes and what the responses should be.
Development of an endoplasmic reticulum-targeting fluorescent probe for the two-photon imaging of hypochlorous acid (HClO) in living cells
Authors: Song Wenhui , Dong Baoli , Lu Yaru , Kong Xiuqi , Mehmood Abdul Hadi , Lin Weiying
Published: August 2019

As an important reactive oxygen species, hypochlorous acid (HClO) could irreversibly destroy Ca2+-ATPase to inhibit Ca2+transport in the endoplasmic reticulum (ER), which may eventually lead to cell dysfunction and cell death.
Photoemission spectroscopy study of structural defects in molybdenum disulfide (MoS2) grown by chemical vapor deposition (CVD)
Authors: Syari’ati Ali , Kumar Sumit , Zahid Amara , Ali El Yumin Abdurrahman , Ye Jianting , Rudolf Petra
Published: August 2019

The fingerprint of structural defects in CVD grown MoS2 was revealed by means of X-ray Photoelectron Spectroscopy (XPS).
An iron incorporation-induced nickel hydroxide multiphase with a 2D/3D hierarchical sheet-on-sheet structure for electrocatalytic water oxidation
Authors: Hao Pin , Zhu Wenqian , Li Liyi , Xin Ying , Xie Junfeng , Lei Fengcai , Tian Jian , Tang Bo
Published: August 2019

An Fe-incorporated Ni(OH)2 multiphase with a unique 2D/3D hierarchical sheet-on-sheet structure exhibits superior catalytic activity contributed by synergistic effects, enhanced electron transport and well-exposed active sites.
High-throughput and ultra-sensitive single-cell profiling of multiple microRNAs and identification of human cancer
Authors: Li Lu , Lu Meng , Fan Yuanyuan , Shui Lingling , Xie Shuting , Sheng Renjie , Si Haibin , Li Qingling , Wang Yiguo , Tang Bo
Published: August 2019

We established an efficient method for single-cell multiple miRNA analysis by droplet microfluidics with high sensitivity and high throughput.
Mononuclear manganese(iii) complexes with reduced imino nitroxide radicals by single-electron transfer and intermolecular hydrogen bonds as an intramolecular structural driving force
Authors: Lecourt Constance , Madanamoothoo Warren , Ferreol Vivian , Bélanger-Desmarais Nicolas , Khrouz Lhoussain , Tommasino Jean-Bernard , Reber Christian , Desroches Cédric , Luneau Dominique
Published: August 2019

One-electron transfer from Mn(ii) ions to an imino nitroxide radical gives mononuclear Mn(iii) complexes of the reduced amino imine-oxide form for which crystal structures evidence hydrogen bonds networks acting as a stabilizing driving-force.
Starch-regulated copper–terephthalic acid as a pH/hydrogen peroxide simultaneous-responsive fluorescent probe for lysosome imaging
Authors: Chen Jian , Si Yubing , Liu Yibiao , Wang Saisai , Wang Shijie , Zhang Ying , Yang Baocheng , Zhang Zuling , Zhang Shouren
Published: August 2019

Starch-regulated copper–terephthalic acid can act as a pH/H2O2 responsive fluorescent probe for lysosome-specific imaging.
Water-soluble diboronic acid-based fluorescent sensors recognizing d-sorbitol
Authors: Fang Guiqian , Bian Zhancun , Liu Daili , Wu Guiying , Wang Hao , Wu Zhongyu , Yao Qingqiang
Published: August 2019

Water-soluble diboronic acid sensor 15c exhibited higher selectivity for d-sorbitol than monoboronic acid sensor 1 and hydroxy derivative 2. And it could be applied for d-sorbitol sensing and analysis in real samples.
A new disulfide Schiff base as a versatile “OFF–ON–OFF” fluorescent–colorimetric chemosensor for sequential detection of CN− and Fe3+ ions: combined experimental and theoretical studies
Authors: Nouri Moghadam Fariba , Amirnasr Mehdi , Eskandari Kiamars , Meghdadi Soraia
Published: August 2019

A new disulfide Schiff base as a versatile “OFF–ON–OFF” fluorescent–colorimetric chemosensor has been synthesized for sequential detection of CN− and Fe3+ ions.
A new healable polymer material based on ultrafast Diels–Alder ‘click’ chemistry using triazolinedione and fluorescent anthracyl derivatives: a mechanistic approach
Authors: Mondal Prantik , Jana Gourhari , Behera Prasanta Kumar , Chattaraj Pratim Kumar , Singha Nikhil K.
Published: August 2019

Development of a new healable polymer based on ultrafast Diels–Alder ‘click’ chemistry using fluorescent anthracyl and TAD derivatives. The ultrafast mechanistic approach is rationalized via Density Functional Theory (DFT) study.
Microphase separation in oriented polymeric chains at the surface of nanomaterials during nanofiber formation
Authors: Janghela Shriram , Devi Sudeepa , Kambo Neelu , Roy Debmalya , Mukhopadhyay Kingsuk , Prasad N. Eswara
Published: August 2019

The significance of the configuration of a nanoscale functional surface on the texture of polymeric chain assemblies during electrospinning for controlled flexible scaffolds.
Temperature dependent energy transfer in Bi/Er codoped barium gallogermanate glasses for tunable and broadband NIR emission
Authors: Xiao Jianhua , Cao Jiangkun , Wang Yafei , Li Xingyu , Wang Xiu , Zhang Jing , Peng Mingying
Published: August 2019

A tunable and further broadened NIR emission can be realized in Bi/Er codoped barium gallogermanate glasses by tuning the Er3+content, the temperature and the pumping schemes.
High voltage outdoor insulator surface condition evaluation using aerial insulator images
Authors: Pernebayeva Damira , Irmanova Aidana , Sadykova Diana , Bagheri Mehdi , James Alex
Published: August 2019

High voltage insulator detection and monitoring via drone‐based aerial images is a cost‐effective alternative in extreme winter conditions and complex terrains. The authors examine different surface conditions of the outdoor electrical insulator that generally occur under winter condition using image processing techniques and state‐of‐the‐art classification methods. Two different types of classification approaches are compared: one method is based on neural networks (e.g. CNN, InceptionV3, MobileNet, VGG16, and ResNet50) and the other method is based on traditional machine learning classifiers (e.g. Bayes Net, Decision Tree, Lazy, Rules, and Meta classifiers). They are evaluated to discriminate the images of insulator surface exposed to freezing, wet, and snowing conditions. The results indicate that traditional machine learning methods with proper selection of features can show high classification accuracy. The classification of the insulator surfaces will assist in determining the insulator conditions, and take preventive measures for its protection.
Adaptive hierarchical coding and modulation scheme over satellite channels
Authors: He Rui , Yang Dewei , Wang Hua , Kuang Jingming
Published: August 2019

In this study, a new scheme called adaptive hierarchical coding and modulation has been proposed, based on Adaptive Coding and Modulation (ACM) and hierarchical modulation (HM). The primary contribution of this study is summarised as the following aspects. Firstly, 16‐ to 64‐APSK constellations with size and labelling optimisation method are proposed for HM, which can be adapted to transmitting multiple hierarchies with different QoS streams and to the non‐linear satellite channels due to a lower peak‐to‐average power ratio compared to traditional hierarchical QAM modulation. Bit channel capacity and Chernoff error bound are introduced to optimise size and labelling of the constellation with interior‐point algorithm and modified binary switch algorithm for a specific channel model to get a better performance. Secondly, combining with optimised constellations, coding and modulation modes set is obtained from using constellation design and optimisation method, with different modulation orders and code rates. And over satellite channels with rain and location attenuation, the proposed scheme is able to adapt itself to a changing channel condition and increase the transmission rate compared with ACM schemes of DVB‐S2 and DVB‐S2X standard.
WDM for multi‐user indoor VLC systems with SCM
Authors: Younus Safwan Hafeedh , Al‐Hameed Aubida A. , Hussein Ahmed Taha , Alresheedi Mohammed T. , Elmirghani Jaafar M.H.
Published: August 2019

A system that employs wavelength division multiplexing (WDM) in conjunction with sub‐carrier multiplexing (SCM) tones is proposed to realise high data rate multi‐user indoor visible light communication (VLC). The SCM tones, which are unmodulated signals, are used to identify each light unit, to find the optimum light unit for each user and to calculate the level of the co‐channel interference (CCI). WDM is utilised to attain a high data rate for each user. In this study, multi‐colour (four colours) laser diodes are utilised as sources of lighting and data communication. One of the WDM colours is used to convey the SCM tones at the beginning of the connection to set up the connection among receivers and light units (to find the optimum light unit for each user). To evaluate the performance of the VLC system, two types of receivers are proposed: an array of non‐imaging receivers and an array of non‐imaging angle diversity receivers. In this study, the effects of diffuse reflections, CCI and mobility on the system performance are considered.
Distributed algorithm to reduce contention in emergency situations by deploying cognitive radio ad‐hoc controllers
Authors: Sudhakaran Chitra , M Suganthi
Published: August 2019

Nowadays, the main focus of emergency communication research is directed to the use of cognitive radio ad‐hoc networks for disaster scenarios. This study addresses an efficient cooperative game‐theoretic channel access scheme for data offloading and cooperation of emergency user using cooperative cognitive ad‐hoc controllers in order to reduce the blocking probability of the newly incoming emergency user. The main objective is to connect all the users who are in need of urgent spectrum and it is considered that their data size is too large. Also, a hybrid overlay–underlay approach was undertaken which provides higher spectrum flexibility. A distributed algorithm is proposed which comprises a criterion assignment, merge and split algorithm and an auction mechanism to provide incentives to those controllers who participate in cooperation. An aggregate throughput of 18% is obtained as an improvement when compared with other conventional heuristics algorithm.
IntelliTC: intelligent inter‐DC traffic controller for the Internet of everything service based on fog computing
Authors: Kwak Ji‐Young , Cho Chunglae , Shin YongYoon , Yang Sunhee
Published: August 2019

As the data size on smart things continue to grow, it becomes inefficient to transfer the massive raw data to centralized cloud datacenters for the analysis of raw data and the deployment of innovative and novel services into various areas such as smart cities, etc. As the concept of Fog Computing, the structure of distributed intelligent infrastructure can address those problems by providing elastic resources and services to end users with smart devices at the edge of network. Hence, through the functions of analytics and flexible control based on the Software‐Defined Network (SDN), it is necessary to provide the SDN‐driven management intelligence, which can maximize network utilization subject to constraints on service priority and resources fairness by differentiating service flows according to the quality requirements. This paper proposes the SDN controller for intelligent inter‐datacenter (inter‐DC) cloud networking, which enables optimal traffic loads distribution across the distributed datacenters with the global inter‐DC view of link states and flow statistics by applying the network‐aware flow scheduling on a policy‐driven inter‐DC traffic control layer. The proposed intelligent inter‐DC controller performs a global resources scheduling mechanism that uses different weights according to the priority of service class in allocating bandwidths based on multi‐layers networking interconnecting the distributed datacenters.
Optimal number of user antennas in a constrained pilot‐length massive MIMO system
Authors: Alwakeel Ahmed S. , Mehana Ahmed Hesham
Published: August 2019

In this study, the authors analyse the performance of a massive multiple‐input multiple‐output network with N‐antenna users. Equipping the user terminal (UT) with a multiple of antennas is usually challenging since it increases the overhead of the channel estimation process (linearly with N). In this study, the authors use semi‐blind (data‐aided) channel estimation that significantly reduces the pilot overhead and analytically obtains the optimal number of antennas that can be mounted at the UT. The proposed channel estimation algorithm is especially useful in cases where a UT can be assigned a single, or generally a few numbers of, pilot sequence(s) although it might have a number of antennas greater than the number of sequences (as the case of 5G proposed solutions); therefore the network does not have to assign more pilots to the user in order to estimate the additional antennas. The authors also characterise the user outage performance when a part of its data is used for the blind channel estimation.
Historical perspective of free space optical communications: from the early dates to today's developments
Authors: Raj Arockia Bazil , Majumder Arun K.
Published: August 2019

This survey article discusses the revolutions of wireless communication technologies right from the prehistoric man's fire signals to today's space optical communications. A brief description of evaluations of communication technologies from the ancient Greece to today's mature telecommunication fields is discussed in this review paper. Principle, significance, demonstration and development of free space optical (FSO) communication technology over different decades are discussed. Major FSO channel limitations, temporal and spatial challenges of FSO communication system and their state‐of‐art mitigation techniques are presented. Classical quantitative analysis of reliability of FSO communication, developments on radio over FSO (RoFSO) and hybrid FSO/RF systems are also explained. Advanced developments of FSO communication techniques such as optical free space wavelength division multiplexing (WDM), sub‐carrier multiplexing (SCM), worldwide interoperability for microwave access (WiMAX), visible light communications (VLC) and vehicular visible light communications (VVLC) are reported. Deep space optical communication systems and next generation FSO wireless terrestrial/global network architecture are summarised. Research challenges of FSO systems for internet of things/everything (IoT/IoE), 5G communication, mobile‐network, terahertz spectrum, quantum communication and underwater optical applications are presented. Based on the review, we outlined the challenges that need to be addressed in near‐future researches to realize full potential FSO communication systems.
Hybrid optimisation for priority‐based scheduling in multi‐user STBC‐MIMO‐OFDM
Authors: Raut Shital N. , Jalnekar Rajesh M.
Published: August 2019

Resource allocation in wireless communication systems is of great concern in order to guarantee the efficient utilisation of scary resources. In space–time block codes‐based multiple‐input multiple‐output with orthogonal frequency division multiplexing (STBC‐MIMO‐OFDM) system, scheduling the appropriate user to the available antenna is the major challenge. To overcome the challenge, this study proposes a priority‐based scheduling mechanism using the hybrid optimisation, Dolphin‐Rider Optimisation (DRO), which is a combination of Dolphin Echolocation Algorithm and Rider Optimisation Algorithm. The prioritisation follows the power and quality of service constraints of the users in such a way that the energy efficiency is enabled in the system. The performance of the system is analysed using the Rayleigh and Rician channels with the transmission media as, text, audio, and image. Moreover, the comparative analysis of the proposed DRO is enabled using three modulation schemes, Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying, and quadrature amplitude modulation. The proposed user scheduling mechanism with the BPSK modulation is found to be effective with a minimal bit error rate and maximal throughput of 3.78×10−7 and 0.875.
EDB‐CHS‐BOF: energy and distance‐based cluster head selection with balanced objective function protocol
Authors: Darabkh Khalid A. , Zomot Jumana N. , Al‐qudah Zouhair
Published: August 2019

In this research, two novel cluster head selection protocols are proposed, namely, Energy and Distance Based Cluster Head Selection (EDB‐CHS) and EDB‐CHS with Balanced Objective Function (EDB‐CHS‐BOF). They mainly aim at balancing energy consumption amongst all sensor nodes, prohibiting their precocious death, and extending the network lifetime. More specifically, in EDB‐CHS protocol, a new cluster shape is proposed and consequently a tight closed‐form expression for the optimal number of cluster heads (CHs) in the network is derived. Additionally, an efficacious CHS algorithm is presented, which is an expression of threshold probability that takes into account the residual energy of sensor nodes, how far they are located from the Base Station (BS), as well as the node's optimal probability of being a CH. On the other hand, the EDB‐CHS‐BOF protocol is proposed mainly to address the matter of having long‐distance communications as a result of obtaining adjacent CHs. In EDB‐CHS‐BOF protocol, a new threshold probability for each sensor node to be a CH in any round is proposed. Not only to this extent, but rather a balanced objective function is proposed to ensure a well‐proportioned distribution of CHs over the network. Simulation results demonstrate the superiority of the proposed protocols over other directly related works in terms of network lifetime and total data delivery.
Performance of grey‐coded IQM‐based optical modulation formats on high‐speed long‐haul optical communication link
Authors: Kakati Dhiman , Arya Subhash C.
Published: August 2019

In this article the performance of grey‐coded advanced optical modulation formats is evaluated on a single‐channel high‐speed long‐haul optical communication link and are compared to the respective differential‐coded modulation formats. Polarisation division multiplexed optical in‐phase quadrature modulator (IQM) structure and homodyne detection scheme are used to realise 100 Gbps quadrature phase‐shift keying (QPSK), 120 Gbps 16‐ary quadrature amplitude modulation (16‐QAM), 360 Gbps 32‐QAM and 480 Gbps 64‐QAM modulation formats. Advanced digital signal processing unit with various pre‐processing and recovery stages such as direct current blocking, normalisation, low‐pass Bessel filter, resampling, quadrature imbalance compensation, chromatic dispersion compensation, non‐linear compensation, timing recovery, adaptive equalisation, down‐sampling, frequency offset estimation, and carrier phase estimation is used at the receiving end to compensate for signal impairments during propagation. Maximum transmission distances of 7200, 1050, 560, and 360 km have been achieved at an acceptable bit error rate for QPSK, 16‐QAM, 32‐QAM, and 64‐QAM, respectively. The grey‐coded systems outperformed the differential‐coded systems regarding optical signal‐to‐noise ratio requirement, receiver sensitivity, and transmission distance.
Blind digital modulation classification for STBC‐OFDM system in presence of CFO and channels estimation errors
Authors: Dehri Brahim , Besseghier Mokhtar , Djebbar A.B. , Dayoub Iyad
Published: August 2019

Here, the authors propose a robust blind digital modulation classification (BDMC) algorithm for space time block coding (STBC)‐based MIMO‐OFDM system in the presence of carrier frequency offset (CFO) and channel estimation errors. Previous papers published on the topic of modulation identification were limited to single‐carrier systems operating over frequency‐flat channels. The problem of joint channel and CFO estimation in conjunction with blind digital modulation classification for STBC‐OFDM in frequency selective channel and in the presence of the impulsive noise has not been addressed before to the best of their knowledge. To cope with performance degradation of BDMC due to CFO and channels errors, they propose joint semi‐blind CFO and channels estimation methods. Higher order statistics (HOS), used for feature extraction, are combined with pattern recognition methods to solve the modulation identification problem. The main contribution of their work is the development of estimators, the study of their impacts on the blind classification capability, and the use of simulations to demonstrate the superior performance of the proposed algorithms.
Output‐based resilient event‐triggered control for networked control systems under denial of service attacks
Authors: Sun Hongtao , Peng Chen , Wang Yulong , Tian Yu‐Chu
Published: August 2019

This study is concerned with the output‐based resilient event‐triggered control for networked control systems (NCSs) subject to denial of service (DoS) attacks, where ‘resilient’ is interpreted as that the NCSs can tolerate a larger time delay with a certain degree of performance degradation when there are DoS attacks. Otherwise, the NCSs run with performance. In order to characterise DoS attacks, an additional positive term which implies the effects of DoS attacks is imposed on the pre‐designed triggering condition. By considering the fact that only partial output measurements can be obtained, the output‐based security performance analysis as well as an output feedback controller design under the proposed event‐triggered strategy is conducted with Lyapunov–Krasovskii method and linear matrix inequalities technique. At last, the simulation results show that the designed controller is resilient to DoS attacks with less dependent on the transmission packets while sacrificing some control performance.
Adaptation in network control systems with hierarchical scheduling
Authors: Soudbakhsh Damoon , Annaswamy Anuradha , Voit Harald
Published: August 2019

The analysis and synthesis of cyber‐physical systems (CPSs) require an integrative approach of the study of the underlying physical and cyber components and their intricate and interactive interconnections. Their implementation using distributed embedded systems (DESs) requires the modelling and control of the entire CPS, where uncertainties may occur both in the physical and in the cyber parts. The focus of this study is on the adaptive control of such CPS. When multiple applications have to be controlled using a DES, often the underlying resources are shared. One of the main implications of this resource contention is the introduction of delays in the control messages reaching their intended destination. The specific set of problems the authors consider here are those where a control implementation leads to delays that are unknown. By separating the known part of the delay from the uncertain part, the authors propose a delay‐aware design for the controller. They derive the underlying models, the requisite adaptive control designs, and the stability of the adaptive system. The authors showed effectiveness of the result and its improvement over non‐adaptive designs using simulation.
RHEVC intra‐prediction mode
Authors: Aldin Noor Baha , Aykaç Mahmut , Baha Aldin Shaima
Published: August 2019

Although the high‐efficiency video codec plays a leading role among the video coding standards, it consumes a lot of memory resources and time processing due to its superior video quality and coding performance. The computation algorithm of rate distortion optimisation is one of the reasons behind the encoder's bottleneck. Therefore, a new technique has been introduced here based on the entropy threshold and size of coding unit, which reduces the coding time and bit rate to be more suitable for real‐time processing. According to the obtained results, the encoding time has been enhanced by 56.596% with a reduction in the bit rate reached to 74% on average.
Authentication of medical images using passive approach
Authors: Prakash Choudhary Shyam , Om Hari , Maheshkar Sushila
Published: August 2019

Telemedicine is getting a lot of popularity. It is because of the way that the medical images are sent over the Internet to share the restorative state of a patient, making the analysis simple for the medical staff. There is, however, a good possibility that the contents of a medical image may be altered due to the openness of the Internet. The watermarking techniques are utilised to keep the integrity of medical images intact. These techniques, however, need some additional information (watermark) to be embedded into the medical images, which may deteriorate their visual quality, leading to false diagnosis. In this study, a non‐intrusive procedure for verification of the medical images is proposed in which the polar cosine transform is used for feature extraction and the PatchMatch algorithm to locate the forged regions. Experimentally, the authors demonstrate that the proposed technique is robust against the noise, blurring, scaling, rotation and JPEG compression.