Quality Factor Research Articles

Design and performance evaluation of a 350 m free space optical communications link for pico-macrocell backhauling

Fibreless optics or free space optical communications (FSOC) has been at the forefront of many academic research in telecommunications due to its numerous benefits of large spectrum, high-speed data transmission, security, low transmit power, unlicensed spectrum and non-interfering links. Among the technical challenges of dense deployment of small cells in heterogeneous networks (HetNet) is a flexible and cost-effective backhaul link. This paper proposes, designs, simulates and evaluates the performance of a 350 m FSOC link under different atmospheric impairments for picocell to macrocell backhauling applications. The performance of the FSOC link is assessed by evaluating bit error rate (BER), eye diagram and quality factor (Q-factor). Results obtained recommend the FSOC link deployment for pico-macrocell backhauling under the weather conditions of clear sky with/without turbulence, heavy rain, heavy haze, heavy fog and wet snow.

Performance of machine learning models to forecast PM10 levels

Machine learning techniques have garnered considerable attention in modern technologies due to their promising outcomes across various domains. This paper presents the comprehensive methodology of an optimized and efficient forecasting approach for Particulate Matter 10, specifically tailored to predefined locations. The execution of a comparative analysis involving eight models enables the identification of the most suitable model that aligns with the primary research objective. Notably, the test results underscore the superior performance of an ensemble model, which integrates state-of-the-art methodologies, surpassing the performance of the other seven state-of-the-art models. Adopting a case-specific methodology with machine learning techniques contributes to achieving a notably high regression coefficient (R²≈1) across all models. Furthermore, the study underscores the potential for future endeavors in predicting location-specific environmental factors.•This study focused on forecasting PM10 with machine learning models with the consideration of air quality factors and meteorological factors•Ensemble model was developed for the forecasting purposes with higher performance.

Factor analysis influencing Mobile JKN user experience using sentiment analysis

<span lang="EN-US">Social security administration for health or Badan Penyelenggara Jaminan Sosial Kesehatan (BPJS Kesehatan), as a public legal entity, has a critical role in the health of the Indonesian population. BPJS Kesehatan introduced the Mobile national health insurance or </span><em><span lang="EN-US">jaminan kesehatan nasional</span></em><span lang="EN-US"> (JKN) application to enhance its services, enabling Indonesians to access it directly. Nevertheless, the rating of the Mobile JKN application on the Google Play Store has shown a gradual decline over time. Therefore, this study was conducted to analyze the factors influencing the user experience of the Mobile JKN application, utilizing the review data obtained from the Google Play Store. Sentiment analysis using the Naïve Bayes (NB) classification model and support vector machine (SVM) combined with synthetic minority oversampling technique (SMOTE) and slang word replacement. The results obtained an accuracy value of 93.33%, precision of 93.76%, recall of 93.33%, and F1-score of 93.43%. A further analysis was conducted using online service quality factors to obtain the main factors influencing the experience of Mobile JKN application users. The evaluation findings revealed that factors of security, ease of use, and timeliness are three fundamental aspects that should be given immediate attention by BPJS Kesehatan while improving the Mobile JKN application in the future.</span>

A Possible X-ray Quasi-periodic Oscillation in the Narrow-line Seyfert 1 Galaxy Mrk 142

A possible quasi-periodic oscillation (QPO) at frequency 7.045 × 10−5 Hz is found in the narrow-line Seyfert 1 galaxy Mrk 142 in the data of XMM-Newton collected on 2020 April 11. We find that the QPO signal is statistically significantly larger than the 5σ level and highly coherent with quality factor Q > 5 at the 0.3–10 keV band by using the method of the Lomb–Scargle Periodogram, the Weighted Wavelet Z-transform and the REDFIT. We analyze the data in 0.3–0.6 keV, 0.6–1 keV, 1–3 keV and 3–10 keV energy bands, and find obvious QPO signals at 0.3–0.6 keV and 1–3 keV bands. We then analyze the time-average spectra and time variability at the QPO frequency of 7.045 × 10−5 Hz, and use a model to fit them. We find that the QPO signal mainly comes from the X-ray hot corona.

Analysis of the evolution and influencing factors of ecological environment quality after the transformation of resource-exhausted cities based on GEE and RSEI: a case study of Xuzhou City, China

ABSTRACT This study used Google Earth Engine (GEE) to get and process Landsat images of Xuzhou from 2008 to 2020, and built remote sensing ecological indices (RSEI). This study analyzed the spatiotemporal features and drivers of ecological environment quality after Xuzhou’s transformation using landscape pattern index, spatial autocorrelation, and geographic detector methods. The results showed that: (1) The ecological environment quality of Xuzhou improved steadily but unevenly from 2008 to 2020; the west and central urban areas had poor but improving quality, while the east had the opposite trend; (2) The landscape pattern indices of ecological environment quality in different regions of Xuzhou did not change consistently from 2008 to 2020; (3) The spatial distribution of ecological environment quality had significant autocorrelation, with high-high clusters in the east and low-low clusters in the center and the urban areas of each district and county; (4) NDVI is the component index that has the greatest impact on the changes in the RSEI. Among the single factors, land use conditions have the strongest influence on ecological environmental quality. After the interaction of dual factors, the explanatory power is stronger than that of any single factor. The research results can support urban planning and design, ecological environment protection, etc. in Xuzhou, and offer insights for monitoring and evaluation of ecological environment quality after the transformation of resource-exhausted cities.

The impact of functional and service quality on perceived security in manufacturing and telecommunication services

PurposeThis research deals with the critical factors of quality and their significance to perceived security as an effort to build a formidable loyalty of customers in a technology driven service environment. The primary purpose of this study is to investigate the key contributing elements of functional and service quality on perceived security and to further analyze its impact on customer satisfaction and loyalty.Design/methodology/approachA hypothesized structure model is proposed and justified using the data collected in the manufacturing and telecommunication service sectors in South Korea through survey with total 647 respondents. To clarify the reliability of model and validity of the proposed hypothesis, AMOS 24.0 software was utilized. Furthermore, two moderating variables were adopted for the depth understanding.FindingsThis study reveals that service quality dominantly influences the level of perceived security due to its characteristics that are mostly formed on the stage of customer-contact activity. This study further provides a strategic methodology for manufacturing and telecommunication firms to foster sustainable growth by focusing on perceived security during the service delivery process.Originality/valueThis finding is particularly important as Ontact technology becomes increasingly critical during the COVID-19 pandemic. It is worthwhile noting that the research outcome of this study may, in turn, trigger the trust issue that need to be combined with quality in the era of Industry 4.0.

Absorption Enhancement in Silicon-Based Dielectric Resonator for Quad-band Terahertz Biosensing

Abstract A technique is implemented to obtain the multi-band perfect absorption (nearly 100%) in an ultrathin silicon-based dielectric resonator (DR) using perturbation. A silicon-based plus-shaped resonator is utilized to design the proposed absorber which provides the four narrow-band absorptions at frequencies of around 5.75, 6.14, 6.48, and 7.24 THz with the level of absorption 54%, 20%, 95%, and 96%, respectively. The plus-shaped resonator is perturbedby cutting slot of plus shape in such a way that it obtains perfect absorption with sufficient guard-band to prevent the multi-band interference in each band. This perturbation provides four absorption peaks at frequencies of around 5.80, 6.27, 6.80, and 7.23 THz, with highly improved absorption in all the bands, i.e., 99.84%, 99.78%, 99.51%, 98.42%, respectively. The ultranarrow absorption peaks with narrow FWHM are suitable for the application of THz biosensing and refractive index analysis. The performance of the proposed absorber is studied with the variation in refractive index of sample. It is found that the proposed absorber provides the high sensitivity 0.186, 0.29, 0.2485, 0.43 THz/RIU and quality factor 280, 185.79, 320.42, and 131.51 for different bands, respectively. The proposed absorber performance is also studied for various THz biosensing applications like the detection of various viruses, malaria, and cancer in the human body at various stages.

Fano resonance in one-dimensional quasiperiodic topological phononic crystals towards a stable and high-performance sensing tool

Phononic crystals (PnCs) emerge as an innovative sensor technology, especially for high-performance sensing applications. This study strives to advance this field by developing new designs of PnC structures that exhibit stability in the face of construction imperfections and deformations, focusing on the evolution of topological PnCs (TPnCs). These designs could be promising to overcome the problem of instability involved in most of the theoretical PnC sensors when they emerge in experimental verification. In particular, the fabrication process of any design could collide with some fluctuations in controlling the size of each component. Thus, Fano resonance is introduced through a one-dimensional (1D) quasiperiodic TPnC. To the best of the author’s knowledge, this study is the first to observe Fano modes in liquid cavities through 1D PnCs. Various quasiperiodic PnC designs are employed to detect the temperature of alcohols (specifically propanol) across an extensive temperature range (160–240 °C). The effects of many geometrical parameters on the sensor stability, such as material thicknesses, are studied. Numerical findings demonstrated that the designed quasiperiodic topological PnCs based on Fibonacci sequence of the second order proved superior performance. This sensing tool provides sensitivity, quality factor and figure-of-merit values of 104,533.33 Hz/°C, 223.69 and 0.5221 (/°C), respectively, through temperature detection of propanol in the range of 160–240 °C.

Enhanced anchor quality factor of an aluminium nitride-on-silicon MEMS resonator using support tethers based on compound leaf-shaped one dimensional phononic crystal

Enhanced anchor quality factor of an aluminium nitride-on-silicon MEMS resonator using support tethers based on compound leaf-shaped one dimensional phononic crystal

Ultra‐Narrow Linewidth Polariton Lasing in Optically Trapped Bose‐Einstein Condensates at Room Temperature

AbstractPolariton lasing via Bose‐Einstein condensation (BEC) provides a peculiar method to achieve low threshold coherent light sources. Until now, the cryogenic operating temperature required for polariton lasers has hampered the development of polaritonics. Here, a novel approach is first reported to realize the ultra‐narrow linewidth polariton lasing under quasi‐3D quantum confinement at room‐temperature (RT). The potential trap landscape is constructed by ring‐shaped optical excitation, wherein the continuum polariton dispersion is modulated into discrete simple harmonic oscillator (SHO) states. The coherent condensation lasing of trapped polaritons occurs beyond the threshold power. Benefiting from the horizontal quantum confinement, the trapped polariton lasing exhibits an ultra‐narrow linewidth (0.7 meV) and excellent quality factor (Q = 3510). Moreover, the second‐order quantum coherence properties of trapped polariton condensation are determined to reveal the quantum phase transition of Bosonic system. The results offer a feasible route for realizing a low‐threshold ultra‐narrow linewidth polariton laser at RT, which significantly facilitates the fabrication of polariton laser and switches on opportunities for future applications.

ANALYSIS OF THE RELATIONSHIP BETWEEN FACTORS THAT INFLUENCE USER SATISFACTION IN GOJEK USING THE FUZZY DEMATEL METHOD

Gojek is one of the most popular online transportation services in Indonesia. The success of Gojek is closely tied to user satisfaction. There are five factors influencing user satisfaction: service quality factor (A), price factor (B), ease of use factor (C), perceived benefit factor (D), and online servicescape factor (E). This research aims to identify which factors most significantly affect user satisfaction with Gojek services among students of the Mathematics Department at UNP. This study in applied research that is described using fuzzy DEMATEL and employs primary data obtained from questionnaire responses. The population of this study consists of students from the Mathematics Department at FMIPA UNP who enrolled in 2022, with a sample size of 75 students using the proportional random sampling technique. The results of this research indicate a significant relationship between the service quality factor (A) and price factor (B). With respective y coordinates of 0.583 and 2.074, the researcher can conclude that the price factor has the most significant influence on user satisfaction with Gojek among students of the Mathematics Department at FMIPA UNP in the 2022 cohort.

Ultra-slow-light and dynamically quantitative optical storage modulation via quasi-BICs

We achieve dynamically tunable dual quasi-bound states in the continuum (quasi-BICs) by implementing them in a silicon–graphene multilayer composite structure and utilize the quasi-BIC modes to achieve ultra-large group delays (velocity of light slows down 105 times), showing 2–3 orders of magnitude higher than the group delays of previous electromagnetically induced transparency modes. The double-layer graphene holds great tuning capability and leads to the dramatically reduced group delay from 1929.82 to 1.58 ps with only 100 meV. In addition, the log-linear variation rule of group delay with Fermi level (Ef) in the range of 0–10 meV is analyzed in detail, and the double-logarithmic function relationship between the group delay and quality factor (Q-factor) is theoretically verified. Finally, the quantitative modulation of the optical storage is further realized in this basis. Our research provides ideas for the reform and upgrading of slow optical devices.

Investigating Stagnant Air Conditions in Almaty: A WRF Modeling Approach

This study investigates stagnant atmospheric conditions in Almaty, Kazakhstan, a city nestled within a complex terrain. These conditions, characterized by weak local winds and inversion layers, trap pollutants within the city, particularly during winter. The Weather Research & Forecasting (WRF) model was employed to simulate atmospheric conditions using Local Climate Zone data. Verification of the model’s accuracy was achieved through comparisons with data from weather stations and the Landsat-9 satellite. The model successfully reproduced the observed daily temperature variations and weak winds during the testing period (13–23 January 2023). Comparisons with radiosonde data revealed good agreement for morning temperature profiles, while underestimating the complexity of the evening atmospheric structure. The analysis focused on key air quality factors, revealing cyclical patterns of ground-level and elevated inversions linked to mountain-valley circulation. The model effectively captured anabatic and katabatic flows. The study further examined the urban heat island (UHI) using a virtual rural method. The UHI exhibited daily variations in size and temperature, with heat transported by prevailing winds and katabatic flows. Statistical analysis of temperature and wind patterns under unfavorable synoptic situations revealed poor ventilation in Almaty. Data from three Januaries (2022/2023/2024) were used to create maps showing average daytime and nighttime air temperatures, wind speed, and frequency of calm winds.

Near-quantum-limited haloscope search for dark-photon dark matter enhanced by a high- Q superconducting cavity

We report new experimental results on the search for dark photons based on a near-quantum-limited haloscope equipped with a superconducting cavity. The loaded quality factor of the superconducting cavity is 6×105, so that the expected signal from dark-photon dark matter can be enhanced by more than one order compared to a copper cavity. A Josephson parametric amplifier with a near-quantum-limited noise temperature has been utilized to minimize the noise during the search. Furthermore, a digital acquisition card based on field programmable gate arrays has been utilized to maximize data collection efficiency with a duty cycle being 100%. This work has established the most stringent constraints on dark photons at around 26.965 μeV. In the future, our apparatus can be extended to search for other dark matter candidates, such as axions and axionlike particles, and scrutinize new physics beyond the Standard Model. Published by the American Physical Society 2024

Mode coupling with Fabry-Perot modes in photonic crystal slabs

Abstract Fabry-Perot (FP) modes are a class of fundamental resonances in photonic crystal (PhC) slabs. Owing to their low quality factors, FP modes are frequently considered as background fields with their resonance nature being neglected. Nevertheless, FP modes can play important roles in some phenomena, as exemplified by their coupling with guided resonance (GR) modes to achieve bound states in the continuum (BIC). Here, we further demonstrate the genuine resonance mode capability of FP modes PhC slabs. Firstly, we utilize temporal coupled-mode theory to obtain the transmittance of a PhC slab based on the FP modes. Secondly, we construct exceptional points (EPs) in both momentum and parameter space through the coupling of FP and GR modes. Furthermore, we identify a Fermi arc connecting two EPs and discuss the far field polarization topology. This work elucidates that the widespread FPs in PhC slabs can serve as genuine resonant modes, facilitating the realization of desired functionalities through mode coupling.

Miniaturized Multi-Cantilever MEMS Resonators with Low Motional Impedance

Microelectromechanical system (MEMS) cantilever resonators suffer from high motional impedance (Rm). This paper investigates the use of mechanically coupled multi-cantilever piezoelectric MEMS resonators in the resolution of this issue. A double-sided actuating design, which utilizes a resonator with a 2.5 μm thick AlN film as the passive layer, is employed to reduce Rm. The results of experimental and finite element analysis (FEA) show agreement regarding single- to sextuple-cantilever resonators. Compared with a standalone cantilever resonator, the multi-cantilever resonator significantly reduces Rm; meanwhile, the high quality factor (Q) and effective electromechanical coupling coefficient (Kteff2) are maintained. The 30 μm wide quadruple-cantilever resonator achieves a resonance frequency (fs) of 55.8 kHz, a Q value of 10,300, and a series impedance (Rs) as low as 28.6 kΩ at a pressure of 0.02 Pa; meanwhile, the smaller size of this resonator compared to the existing multi-cantilever resonators is preserved. This represents a significant advancement in MEMS resonators for miniaturized ultra-low-power oscillator applications.

A carbon nanotube metamaterial sensor showing slow light properties based on double plasmon-induced transparency.

In this study, we proposed a bifunctional sensor of high sensitivity and slow light based on carbon nanotubes (CNTs). An array of left semicircular ring (LSR), right semicircular ring (RSR), and circular ring (CR) resonators are utilized to form the proposed metamaterial. The proposed structure can achieve double plasmon-induced transparency (PIT) effects under the excitation of a TM-polarization wave. The double PIT originated from the destructive interference between two bright modes and a dark mode. A coupled harmonic oscillator model is used to describe the destructive interference between the two bright modes and a dark mode, and the simulation results agree well with the calculated results. Moreover, we investigate the influence of the coupling distance, period, and flare angle on the PIT spectra. The relationship between the resonant frequencies, full width at half maximum (FWHM), amplitudes, quality factors (Q), and the coupling distance is also studied. Finally, a high sensitivity of 1.02 THz RIU-1 is obtained, and the transmission performance can be maintained at a good level when the incident angle is less than 40°. Thus, the sensor can cope with situations where electromagnetic waves are not perpendicular to the structure's surface. The maximum figure of merit (FOM) can reach about 8.26 RIU-1; to verify the slow light property of the device, the slow light performance of the proposed structure is investigated, and a maximum time delay (TD) of 22.26 ps is obtained. The proposed CNT-based metamaterial can be used in electromagnetically induced transparency applications, such as sensors, optical memory devices, and flexible terahertz functional devices.

Online Impulsive Buying Behavior of Mobile Site Shoppers in Turkey: A Mediation Analysis

Objective: The study investigates the correlation between mobile site quality (MSQ) factors and perceived enjoyment. It also explores the link between perceived enjoyment and both electronic word-of-mouth (eWOM) and online impulsive buying behavior of mobile site shoppers in Turkey. Theoretical Framework: The theoretical framework considers MSQ factors (contact, responsiveness, efficiency, fulfillment, and privacy), perceived enjoyment, eWOM and online impulsive buying behavior. Method: This study employs a quantitative methodology, utilizing a questionnaire as the primary data collection tool, designed for a sample size of 676 individuals fromTurkey selected through Purposive Sampling technique. The data analysis method employed is Structural Equation Modeling (SEM), utilizing the AMOS software to assess the goodness of fit statistics of the measurement model with the empirical data. Results and Discussion: The results showed that the contact, efficieny, and the privacy of mobile site influence perceived enjoyment positively. Perceived enjoyment influences both eWOM and online impulsive buying behavior positively and finally eWOM influences online impulsive purchasing behavior positively as well. Research Implications: The results suggest that improvements in MSQ factors of the contact, efficieny, and the privacy can provide mobile site shoppers more enjoyment and while perceived enjoyment has been increasing the probability of mobile site shoppers’ impulsive buying behavior, it also provides more effective marketing campaigns with less costs for the mobile retailers in Turkey. Originality/Value: This study makes a significant contribution to the existing online impulsive behavior literature by focusing on the MSQ elements of mobile shopping sites among shoppers in Turkey. It examines the mediation of perceived enjoyment between all MSQ elements and online impulsive buying behavior, as well as eWOM between perceived enjoyment and online impulsive buying behavior, which have not been extensively explored in prior research.

Stiffness calibration of qPlus sensors at low temperature through thermal noise measurements

Non-contact atomic force microscopy (nc-AFM) offers a unique experimental framework for topographical imaging of surfaces with atomic and/or sub-molecular resolution. The technique also permits to perform frequency shift spectroscopy to quantitatively evaluate the tip–sample interaction forces and potentials above individual atoms or molecules. The stiffness of the probe, k, is then required to perform the frequency shift-to-force conversion. However, this quantity is generally known with little precision. An accurate stiffness calibration is therefore mandatory if accurate force measurements are targeted. In nc-AFM, the probe may either be a silicon cantilever, a quartz tuning fork (QTF), or a length extensional resonator (LER). When used in ultrahigh vacuum (UHV) and at low temperature, the technique mostly employs QTFs, based on the so-called qPlus design, which actually covers different types of sensors in terms of size and design of the electrodes. They all have in common a QTF featuring a metallic tip glued at the free end of one of its prongs. In this study, we report the stiffness calibration of a particular type of qPlus sensor in UHV and at 9.8 K by means of thermal noise measurements. The stiffness calibration of such high-k sensors, featuring high quality factors (Q) as well, requires to master both the acquisition parameters and the data post-processing. Our approach relies both on numerical simulations and experimental results. A thorough analysis of the thermal noise power spectral density of the qPlus fluctuations leads to an estimated stiffness of the first flexural eigenmode of ≃2000 N/m, with a maximum uncertainty of 10%, whereas the static stiffness of the sensor without tip is expected to be ≃3300 N/m. The former value must not be considered as being representative of a generic value for any qPlus, as our study stresses the influence of the tip on the estimated stiffness and points towards the need for the individual calibration of these probes. Although the framework focuses on a particular kind of sensor, it may be adapted to any high-k, high-Q nc-AFM probe used under similar conditions, such as silicon cantilevers and LERs.

Can relative abundance of diatoms (RAD) serve as an indicator for the water quality assessment in river-connected lakes? A case study at Dongting Lake

In this study, 15 sampling sites were set up in Dongting Lake, a typical river-connected lake in China, to investigate water quality and diatioms in March, June, September and December from year 2017 to 2022. Seven diatom indices, including relative abundance of diatoms (RAD), percentage motile diatoms (PMD), generic diatom index (GDI), diatom quotient (DU), pollution tolerance index for diatoms (PTI), trophic diatom index (TDI), and Pampean diatom index (IDP), were selected to screen the adaptability of water quality assessment comparing with the Nemero index (NI), which is simple to calculate and has always been the main method for water quality assessment in Dongting Lake. The results from 2017 to 2019 showed that the diatom density in Dongting Lake ranged from 0.7 × 104 to 85.5 × 104 ind./L, with a certain decreasing trend. The spatial and temporal changes of some water quality factors were obvious, just like the temperature of water (WT), ammonia nitrogen (NH4+–N), dissolved oxygen (DO) and the comprehensive trophic level index (∑TLI) ranged from 45.99 to 50.72, with an average value of 47.85, indicating that the overall condition of Dongting Lake was medium nutrition. Correlation analysis showed that PTI, RAD and PMD could represent the information of DU, GDI, TDI and IDP, and were significantly positively correlated with DO (p < 0.01), while significantly negatively correlated with electrical conductivity (Cond), potassium permanganate (CODMn), biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr) and ∑TLI (p < 0.001). The index verification results from year 2020 to 2022 showed that PTI, RAD and PMD were all significantly positively correlated with NI (p < 0.001). Taking into account the data integrity of the index calculation and the difficulty degree, RAD was finally selected as the biological indicator for evaluating the water quality of Dongting Lake. The results of this study provide a new path or alternative method for water quality assessment of the river-connected lakes.