Flat multifunctional liquid crystal elements through multi-dimensional information multiplexing

Flat optical elements have attracted enormous attentions and act as promising candidates for the next generation of optical components.As one of the most outstanding representatives,liquid crystal(LC)has been widely applied in flat panel display industries and inspires the wavefront modulation with the development of LC alignment techniques.However,most LC elements perform only one type of optical manipulation and are difficult to realize the multifunctionality and light integration.Here,flat multifunctional liquid crystal elements(FMLCEs),merely composed of anisotropic LC molecules with space-variant orientations,are presented for multichannel information manipulation by means of polarization,space and wavelength multiplexing.Specifically,benefiting from the unique light response with the change of the incident polarization,observation plane,and working wavelength,a series of FMLCEs are demonstrated to achieve distinct near-and far-field display functions.The proposed strategy takes full advantage of basic optical parameters as the decrypted keys to improve the information capacity and security,and we expect it to find potential applications in information encryption,optical anti-counterfeiting,virtual/augmented reality,etc.

An Investigation on Open-RAN Specifications:Use Cases,Security Threats,Requirements,Discussions

The emergence of various technologies such as terahertz communications,Reconfigurable Intelligent Surfaces(RIS),and AI-powered communication services will burden network operators with rising infrastructure costs.Recently,the Open Radio Access Network(O-RAN)has been introduced as a solution for growing financial and operational burdens in Beyond 5G(B5G)and 6G networks.O-RAN promotes openness and intelligence to overcome the limitations of traditional RANs.By disaggregating conventional Base Band Units(BBUs)into O-RAN Distributed Units(O-DU)and O-RAN Centralized Units(O-CU),O-RAN offers greater flexibility for upgrades and network automation.However,this openness introduces new security challenges compared to traditional RANs.Many existing studies overlook these security requirements of the O-RAN networks.To gain deeper insights into the O-RAN system and security,this paper first provides an overview of the general O-RAN architecture and its diverse use cases relevant to B5G and 6G applications.We then delve into specifications of O-RAN security threats and requirements,aiming to mitigate security vulnerabilities effectively.By providing a comprehensive understanding of O-RAN architecture,use cases,and security considerations,thisworkserves as a valuable resource for future research in O-RAN and its security.

The Bright Single Pulse Emission from PSR B1133+16

We have conducted a comprehensive investigation into the bright single pulse emission from PSR B1133+16using the Giant Metrewave Radio Telescope.High time resolution data(61μs)were obtained at a center frequency of 322 MHz with a bandwidth of 32 MHz over a continuous observation period of 7.45 hr.A total of 1082 bright pulses were sporadically detected with peak flux densities ranging from 10 to 23 times stronger than the average pulse profile.However,no giant pulse-like emission with a relative pulse energy larger than 10 and extremely short duration was detected,indicating that these bright pulses cannot be categorized as giant pulse emission.The majority of these bright pulses are concentrated in pulse phases at both the leading and trailing windows of the average pulse profile,with an occurrence ratio of approximately 2.74.The pulse energy distribution for all individual pulses can be described by a combination of two Gaussian components and a cutoff power-law with an index of α=-3.2.An updated nulling fraction of 15.35%±0.45% was determined from the energy distribution.The emission of individual pulses follows a log-normal distribution in peak flux density ratio.It is imperative that regular phase drifting in bright pulse sequence is identified in both the leading and trailing components for the first time.Possible physical mechanisms are discussed in detail to provide insights into these observations.

Non-Gaussian quantum states generated via quantum catalysis and their statistical properties

A new kind of non-Gaussian quantum catalyzed state is proposed via multiphoton measurements and two-mode squeezing as an input of thermal state.The characteristics of the generated multiphoton catalysis output state depends on the thermal parameter,catalyzed photon number and squeezing parameter.We then analyze the nonclassical properties by examining the photon number distribution,photocount distribution and partial negativity of the Wigner function.Our findings indicate that nonclassicality can be achieved through the implementation of multiphoton catalysis operations and modulated by the thermal parameter,catalyzed photon number and squeezing parameter.

A Systematic Literature Review of Machine Learning and Deep Learning Approaches for Spectral Image Classification in Agricultural Applications Using Aerial Photography

Recently,there has been a notable surge of interest in scientific research regarding spectral images.The potential of these images to revolutionize the digital photography industry,like aerial photography through Unmanned Aerial Vehicles(UAVs),has captured considerable attention.One encouraging aspect is their combination with machine learning and deep learning algorithms,which have demonstrated remarkable outcomes in image classification.As a result of this powerful amalgamation,the adoption of spectral images has experienced exponential growth across various domains,with agriculture being one of the prominent beneficiaries.This paper presents an extensive survey encompassing multispectral and hyperspectral images,focusing on their applications for classification challenges in diverse agricultural areas,including plants,grains,fruits,and vegetables.By meticulously examining primary studies,we delve into the specific agricultural domains where multispectral and hyperspectral images have found practical use.Additionally,our attention is directed towards utilizing machine learning techniques for effectively classifying hyperspectral images within the agricultural context.The findings of our investigation reveal that deep learning and support vector machines have emerged as widely employed methods for hyperspectral image classification in agriculture.Nevertheless,we also shed light on the various issues and limitations of working with spectral images.This comprehensive analysis aims to provide valuable insights into the current state of spectral imaging in agriculture and its potential for future advancements.

Photothermal catalytic C-C coupling to ethylene from CO_(2) with high efficiency by synergistic cooperation of oxygen vacancy and half-metallic WTe_(2)

Photothermal catalytic CO_(2) conversion provides an effective solution targeting carbon neutrality by synergistic utilization of photon and heat.However,the C-C coupling initiated by photothermal catalysis is still a big challenge.Herein,a three-dimensional(3D)hierarchical W_(18)O_(49)/WTe_(2) hollow nanosphere is constructed through in-situ embodying of oxygen vacancy and tellurium on the scaffold of WO_(3).The light absorption towards near-infrared spectral region and CO_(2) adsorption are enhanced by the formation of half-metal WTe_(2) and the unique hierarchical hollow architecture.Combining with the generation of oxygen vacancy with strengthened CO_(2) capture,the photothermal effect on the samples can be sufficiently exploited for activating the CO_(2) molecules.In particular,the close contact between W_(18)O_(49)and WTe_(2) largely promotes the photoinduced charge separation and mass transfer,and thus the~*CHO intermediate formation and fixedness are facilitated.As a result,the C-C coupling can be evoked between tungsten and tellurium atoms on WTe_(2).The ethylene production by optimized W_(18)O_(49)/WTe_(2) reaches 147.6μmol g^(-1)with the selectivity of 80%.The in-situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)and density functional theory(DFT)calculations are performed to unveil the presence and significance of aldehyde intermediate groups in C-C coupling.The half-metallic WTe_(2) cocatalyst proposes a new approach for efficient CO_(2) conversion with solar energy,and may especially create a new platform for the generation of multi-carbon products.

SNR and RSSI Based an Optimized Machine Learning Based Indoor Localization Approach:Multistory Round Building Scenario over LoRa Network

In situations when the precise position of a machine is unknown,localization becomes crucial.This research focuses on improving the position prediction accuracy over long-range(LoRa)network using an optimized machine learning-based technique.In order to increase the prediction accuracy of the reference point position on the data collected using the fingerprinting method over LoRa technology,this study proposed an optimized machine learning(ML)based algorithm.Received signal strength indicator(RSSI)data from the sensors at different positions was first gathered via an experiment through the LoRa network in a multistory round layout building.The noise factor is also taken into account,and the signal-to-noise ratio(SNR)value is recorded for every RSSI measurement.This study concludes the examination of reference point accuracy with the modified KNN method(MKNN).MKNN was created to more precisely anticipate the position of the reference point.The findings showed that MKNN outperformed other algorithms in terms of accuracy and complexity.

Uphill or downhill?Cropland use change and its drivers from the perspective of slope spectrum

The continuous decrease of low-slope cropland resources caused by construction land crowding poses huge threat to regional sustainable development and food security.Slope spectrum analysis of topographic and geomorphic features is considered as a digital terrain analysis method which reflects the macro-topographic features by using micro-topographic factors.However,pieces of studies have extended the concept of slope spectrum in the field of geoscience to construction land to explore its expansion law,while research on the slope trend of cropland from that perspective remains rare.To address the gap,in virtue of spatial analysis and geographically weighted regression(GWR)model,the cropland use change in the Yangtze River Basin(YRB)from 2000 to 2020 was analyzed and the driving factors were explored from the perspective of slope spectrum.Results showed that the slope spectrum curves of cropland area-frequency in the YRB showed a first upward then a downward trend.The change curve of the slope spectrum of cropland in each province(municipality)exhibited various distribution patterns.Quantitative analysis of morphological parameters of cropland slope spectrum revealed that the further down the YRB,the stronger the flattening characteristics,the more obvious the concentration.The province experienced the greatest downhill cropland climbing(CLC)was Shannxi,while province experienced the highest uphill CLC was Zhejiang.The most common cropland use change type in the YRB was horizontal expansion type.The factors affecting average cropland climbing index(ACCI)were quite stable in different periods,while population density(POP)changed from negative to positive during the study period.This research is of practical significance for the rational utilization of cropland at the watershed scale.

AI-Driven Learning Management Systems:Modern Developments, Challenges and Future Trends during theAge of ChatGPT

COVID-19 pandemic restrictions limited all social activities to curtail the spread of the virus.The foremost and most prime sector among those affected were schools,colleges,and universities.The education system of entire nations had shifted to online education during this time.Many shortcomings of Learning Management Systems(LMSs)were detected to support education in an online mode that spawned the research in Artificial Intelligence(AI)based tools that are being developed by the research community to improve the effectiveness of LMSs.This paper presents a detailed survey of the different enhancements to LMSs,which are led by key advances in the area of AI to enhance the real-time and non-real-time user experience.The AI-based enhancements proposed to the LMSs start from the Application layer and Presentation layer in the form of flipped classroom models for the efficient learning environment and appropriately designed UI/UX for efficient utilization of LMS utilities and resources,including AI-based chatbots.Session layer enhancements are also required,such as AI-based online proctoring and user authentication using Biometrics.These extend to the Transport layer to support real-time and rate adaptive encrypted video transmission for user security/privacy and satisfactory working of AI-algorithms.It also needs the support of the Networking layer for IP-based geolocation features,the Virtual Private Network(VPN)feature,and the support of Software-Defined Networks(SDN)for optimum Quality of Service(QoS).Finally,in addition to these,non-real-time user experience is enhanced by other AI-based enhancements such as Plagiarism detection algorithms and Data Analytics.

Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed Ethylene Chain-Walking Polymerization

The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.

Telecom-band multiwavelength vertical emitting quantum well nanowire laser arrays

Highly integrated optoelectronic and photonic systems underpin the development of next-generation advanced optical and quantum communication technologies,which require compact,multiwavelength laser sources at the telecom band.Here,we report on-substrate vertical emitting lasing from ordered InGaAs/InP multi-quantum well core–shell nanowire array epitaxially grown on InP substrate by selective area epitaxy.To reduce optical loss and tailor the cavity mode,a new nanowire facet engineering approach has been developed to achieve controlled quantum well nanowire dimensions with uniform morphology and high crystal quality.Owing to the strong quantum confinement effect of InGaAs quantum wells and the successful formation of a vertical Fabry–Pérot cavity between the top nanowire facet and bottom nanowire/SiO_(2) mask interface,stimulated emissions of the EH11a/b mode from single vertical nanowires from an on-substrate nanowire array have been demonstrated with a lasing threshold of~28.2μJ cm^(−2) per pulse and a high characteristic temperature of~128 K.By fine-tuning the In composition of the quantum wells,room temperature,single-mode lasing is achieved in the vertical direction across a broad near-infrared spectral range,spanning from 940 nm to the telecommunication O and C bands.Our research indicates that through a carefully designed facet engineering strategy,highly ordered,uniform nanowire arrays with precise dimension control can be achieved to simultaneously deliver thousands of nanolasers with multiple wavelengths on the same substrate,paving a promising and scalable pathway towards future advanced optoelectronic and photonic systems.

Entangled States Used in Remote Information Concentration and Their Properties

We analyse a process of remote information concentration achieved by the W state. The result turns out to be neither as good as performed by the GHZ state nor as by the Smolin bound entangled state. Based on this particular phenomenon, the properties of the three entangled states are realized.

Deterministic quantum teleportation and information splitting via a peculiar W-class state

In the paper （Phys. Rev. 2006 A 4 062320） Agrawal et al. have introduced a kind of W-class state which can be used for the quantum teleportation of single-particle state via a three-particle von Neumann measurement, and they thought that the state could not be used to teleport an unknown state by making two-particle and one-particle measurements. Here we reconsider the features of the W-class state and the quantum teleportation process via the W-class state. We show that, by introducing a unitary operation, the quantum teleportation can be achieved deterministically by making two-particle and one-particle measurements. In addition, our protocol is extended to the process of teleporting two-particle state and splitting information.

Identification and Validation of Social Media Socio-Technical Information Security Factors with Respect to Usable-Security Principles

The goal of this manuscript is to present a research finding, based on a study conducted to identify, examine, and validate Social Media (SM) socio-technical information security factors, in line with usable-security principles. The study followed literature search techniques, as well as theoretical and empirical methods of factor validation. The strategy used in literature search includes Boolean keywords search, and citation guides, using mainly web of science databases. As guided by study objectives, 9 SM socio-technical factors were identified, verified and validated. Both theoretical and empirical validation processes were followed. Thus, a theoretical validity test was conducted on 45 Likert scale items, involving 10 subject experts. From the score ratings of the experts, Content Validity Index (CVI) was calculated to determine the degree to which the identified factors exhibit appropriate items for the construct being measured, and 7 factors attained an adequate level of validity index. However, for reliability test, 32 respondents and 45 Likert scale items were used. Whereby, Cronbach’s alpha coefficient (α-values) were generated using SPSS. Subsequently, 8 factors attained an adequate level of reliability. Overall, the validated factors include;1) usability—visibility, learnability, and satisfaction;2) education and training—help and documentation;3) SM technology development—error handling, and revocability;4) information security —security, privacy, and expressiveness. In this case, the confirmed factors would add knowledge by providing a theoretical basis for rationalizing information security requirements on SM usage.

Development of Web Mapping Application for Spatial Ecotourism Information Using QGIS Plugin and Freely Available Web Platforms in North West Highlands of Ethiopia a Case Study: Chokie Mountain Watersheds

Ecotourism is a sustainable, green and smokeless industry of the society by providing alternative source to the livelihood and local community, in order to re-naturalize the environment to bring the man closer to the natural environment. The use of web application has changed the way tourists gather information about tourist attraction spots of the research area. The aim of the study is to assess and identify ecotourism attraction sites of Chokie Mountain watersheds for touristic activities to develop a web-based GIS mapping portal for the improvement of nature-based ecotourism activities. The web-based GIS portal for Web Mapping Application is available for the user with the skills necessary to create standard web mapping services. We have implemented web mapping services based on formal cartographic visualization rules in the open source QGIS software and threejs JavaScript plugin. Threejs plugin is used for 3D visualization, interaction and export terrain data, map canvas image and vector data to HTML page and JS. The result of web-based GIS portal supports spatial and non-spatial database of tourist attraction and tourist service data with attractive user interface.

Medical Information Breaches Occurrence with Respect to Social Media Usage, in Selected Medical Institutions in Uganda

The purpose of this manuscript is to present research findings based on the reported cases of medical information breaches due to Social Media (SM) usage, in selected medical institutions in Uganda. The study employed online survey techniques. Altogether, 710 questionnaires (Google forms) were developed, and operationalized. The main respondents included 566 medical students, and 143 medical staff from Mbarara University of Science and Technology (MUST), and Kampala International University (KIU), accordingly. Using SPSS, the main statistical analysis tools employed include frequency distribution summary, and Chi-square (x2) test. According to the frequency distribution summary, 27% to 42% of the respondents within categorical divides acknowledged occurrence of medical information breaches due to SM usage. Notably, higher levels of the breaches were reported among male students (64%), age-group 18 to 35 years (68%), and WhatsApp users (63%). On the other hand, Chi-square results showed significant levels (p p > 0.05) between medical institutions and medical information breaches. Overall, the vulnerable areas of the breaches identified would serve as important reference points in the process of rationalizing SM usage in medical institutions. Nevertheless, further studies could focus on identification of the key SM usage factors associated with medical information breaches in medical institutions in Uganda.

Broadband and continuous wave pumped second-harmonic generation from microfiber coated with layered GaSe crystal

The conversion-efficiency for second-harmonic(SH)in optical fibers is significantly limited by extremely weak second-order nonlinearity of fused silica,and pulse pump lasers with high peak power are widely employed.Here,we propose a simple strategy to efficiently realize the broadband and continuous wave(CW)pumped SH,by transferring a crystalline GaSe coating onto a microfiber with phase-matching diameter.In the experiment,high efficiency up to 0.08%W-1mm-1 is reached for a C-band pump laser.The high enough efficiency not only guarantees SH at a single frequency pumped by a CW laser,but also multi-frequencies mixing supported by three CW light sources.Moreover,broadband SH spectrum is also achieved under the pump of a superluminescent light-emitting diode source with a 79.3 nm bandwidth.The proposed scheme provides a beneficial method to the enhancement of various nonlinear parameter processes,development of quasi-monochromatic or broadband CW light sources at new wavelength regions.

Solvent-free fabrication of broadband WS2 photodetectors on paper

Paper-based devices have attracted extensive attention due to the growing demand for disposable flexible electronics.Herein,we integrate semiconducting devices on cellulose paper substrate through a simple abrasion technique that yields high-performance photodetectors.A solvent-free WS_(2) film deposited on paper favors an effective electron-hole separation and hampers recombination.The as-prepared paper-based WS2 photodetectors exhibit a sensitive photoresponse over a wide spectral range spanning from ultraviolet(365 nm)to near-infrared(940 nm).Their responsivity value reaches up to~270 mA W^(−1) at 35 V under a power density of 35 mW cm^(−2).A high performance photodetector was achieved by controlling the environmental exposure as the ambient oxygen molecules were found to decrease the photoresponse and stability of the WS_(2) photodetector.Furthermore,we have built a spectrometer using such a paperbased WS_(2) device as the photodetecting component to illustrate its potential application.The present work could promote the development of cost-effective disposable photodetection devices.

Time-sequential color code division multiplexing holographic display with metasurface

Color metasurface holograms are powerful and versatile platforms for modulating the amplitude,phase,polarization,and other properties of light at multiple operating wavelengths.However,the current color metasurface holography can only realize static manipulation.In this study,we propose and demonstrate a multiplexing metasurface technique combined with multiwavelength code-division multiplexing(CDM)to realize dynamic manipulation.Multicolor code references are utilized to record information within a single metasurface and increase the information capacity and security for anticracks.A total of 48 monochrome images consisting of pure color characters and multilevel color video frames were reconstructed in dual polarization channels of the birefringent metasurface to exhibit high information density,and a video was displayed via sequential illumination of the corresponding code patterns to verify the ability of dynamic manipulation.Our approach demonstrates significant application potential in optical data storage,optical encryption,multiwavelengthversatile diffractive optical elements,and stimulated emission depletion microscopy.

Trajectory equation of a lump before and after collision with other waves for generalized Hirota–Satsuma–Ito equation

Based on the Hirota bilinear and long wave limit methods,the hybrid solutions of m-lump with n-soliton and nbreather wave for generalized Hirota–Satsuma–Ito(GHSI)equation are constructed.Then,by approximating solutions of the GHSI equation along some parallel orbits at infinity,the trajectory equation of a lump wave before and after collisions with n-soliton and n-breather wave are studied,and the expressions of phase shift for lump wave before and after collisions are given.Furthermore,it is revealed that collisions between the lump wave and other waves are elastic,the corresponding collision diagrams are used to further explain.