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Search results for: WIDE BAND MODELS
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Interpretation of Structural Parameters for Models with Spatial Autoregression
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Multiobjective Newsvendor Models with CVaR for Flower Industry
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Method of lines for physiologically structured models with diffusion
PublicationWe deal with a size-structured model with diffusion. Partial differential equations are approximated by a large system of ordinary differential equations. Due to a maximum principle for this approximation method its solutions preserve positivity and boundedness. We formulate theorems on stability of the method of lines and provide suitable numerical experiments.
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Reduced-order models in the finite element analysis
PublicationA novel technique of incorporating macromodels into finite element electromagnetic analysis of waveguide components is presented. Macromodels are generated by using a model order reduction algorithm (ENOR), which results in significant decrease of the number of variables, that describe the computational region. Proposed technique allows for using a few independent macromodels as well as to duplicating one macromodel in many subregions...
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Alcohol dehydrogenase and its simple inorganic models
PublicationW pierwszej części pracy przeglądowej przedstawiono aktualny stan wiedzy nt mechanizmu działania zależnej od cynku dehydrogenazy alkoholowej. Następnie omówiono dane strukturalne i spektroskopowe uzyskane przy pomocy prostych związków modelowych - na ogół tiolanów cynku i niektórych innych metali przejściowych. Opisano również próby zastosowania prostych kompleksów nieorganicznych naśladujących budowę miejsca aktywnego dehydrogenazy...
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Hierarchical random models in road transport safety
PublicationIn this paper multilevel approach to the issue of road safety level on the road network of European regions, classified as NUTS 2 in statistical databases of the EU, has been presented. The risk calculated as the number of death casualties in road accidents per 100,000 inhabitants of a given region has Poisson distribution. Therefore, generalized Poisson model has been assumed in the modelling process. Multilevel stochastic analysis...
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Hybrid, Approximate Models of Distributed-Parameter Systems
PublicationThe paper introduces the method of distributed-parameter systems modelling. It enables to obtain low order modal model of the system that experiences Coriolis acceleration component and gyroscopic effect. In such cases, corresponding system equations are non-self-adjoined. To solve this problem modal reduced model is built up for the system without Coriolis acceleration or gyroscopic effect terms. These phenomena are next included...
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A digital cartographic source for numerical models in hydrology
PublicationAutorzy prowadzą analizę wykorzystania i przydatności cyfrowych danych kartograficznych w rozwiązywaniu przestrzennych zagadnień hydrologicznych. Szczególne znaczenie dla prowadzonych analiz mają DTM i DEM. Są one źródłem bezpośrednich wielkości wejściowych modelu hydrologicznego i dodatkowo pozwalają na szersze możliwości prezentacji otrzymanego rozwiązania.
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Low-Cost Surrogate Models for Microwave Filters
PublicationA novel low-cost kriging-based multivariable parametric macromodeling technique for microwave filters is presented. Kriging is used to model both the residues and poles of a microwave filter's reflection coefficient, and the zeros of the transmission coefficient. The proposed residue-pole-zero (RPZ) technique is demonstrated to efficiently model a high dimensional (8D) microwave filter with pseudoelliptic characteristics.
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Evolution of models for sorption of PAHs and PCBs on geosorbents.
PublicationWiedza o tym gdzie są zlokalizowane zanieczyszczenia obecne w osadzie oraz z jaką siłą związane są one z osadem jest niezbędna do oszacowania stopnia i skuteczności procesów remediacjyjnych oraz określenia dostępności, mobilności i toksyczności osadów. Dlatego, aby zrozumieć i poznać procesy zachodzące w tak skomplikowanej matrycy, jaką stanowią osady denne/gleby konstruowane są teoretyczne modele matematyczne opisujące prawdopodobny...
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The application of microscopic models in the study of pedestrian traffic
PublicationCities (especially in Central and Eastern Europe) focus on improving the road network, which aims to improve the efficiency of motor traffic and minimize congestion. Most of existing tools for analysing the effectiveness of urban transport networks do not assume to analyse the impact of walking and cycling on efficiency of transport systems. It is therefore necessary to develop solutions...
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Models and soft modelling in economics and virtual markets.
PublicationPrzedstawiono wprowadzenie do rynków wirtualnych, następnie zaproponowano podstawy miękkiego opisowego modelowania tych rynków. Przedstawione podejście potraktowano jako pierwszy krok w procesie budowy docelowego modelu wyjaśniającego.
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Concept of fuzzy models for social engieering system.
PublicationW artykule przedstawiono możliwości zastosowania teorii zbiorów rozmytych do modelowania systemów społecznych. Przedstawiono wybrane przykłady modelowania systemów technicznych oraz wskazano na ograniczenia modelowania dla systemów społecznych. Szczegółowo omówiono model zarządzania przedsięwzięciami informatycznymi jako przykład modelowania systemu społeczno technicznego.
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Enhancing rheological muscle models with stochastic processes
PublicationPurpose: Biological musculoskeletal systems operate under variable conditions. Muscle stiffness, activation signals, and loads change during each movement. The presence of noise and different harmonic components in force production significantly influences the behaviour of the muscular system. Therefore, it is essential to consider these factors in numerical simulations. Methods: This study aims to develop a rheological mathematical...
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Comparison of Selected Neural Network Models Used for Automatic Liver Tumor Segmentation
PublicationAutomatic and accurate segmentation of liver tumors is crucial for the diagnosis and treatment of hepatocellular carcinoma or metastases. However, the task remains challenging due to imprecise boundaries and significant variations in the shape, size, and location of tumors. The present study focuses on tumor segmentation as a more critical aspect from a medical perspective, compared to liver parenchyma segmentation, which is the...
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Correlation between in vitro and in vivo data on food digestion. What can we predict with static in vitro digestion models?
PublicationDuring the last decade, there has been a growing interest in understanding food's digestive fate in order to strengthen the possible effects of food on human health. Ideally, food digestion should be studied in vivo on humans but this is not always ethically and financially possible. Therefore, simple in vitro digestion models mimicking the gastrointestinal tract have been proposed as alternatives to in vivo experiments. Thus,...
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Firing map for periodically and almost-periodically driven integrate-and-fire models: a dynamical systems approach
PublicationWe consider the Leaky Integrate-and-Fire and Perfect Integrator models of neuron’s dynamics with the input function being periodic and almost-periodic (in the sense of Stepanov). In particular we analyze properties and dynamics of the so-called firing map, which iterations give timings of consecutive spikes of a neuron. In case of a periodic input function we provide a detailed description of the sequence of interspike-intervals,...
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Matrix Strengthening the Identification of Observations with Split Functional Models in the Squared Msplit(q) Estimation Process
PublicationThis article addresses the issue of raising the level of identification of observations with either single or more split functional models in the squared Msplit(q) estimation process. The theoretical part of the study presents the theoretical grounds for the classical method for estimating parameters in a split functional model and proposes a modification of the computational algorithm to increase the quality of the determinations...
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Optical properties of the chemotherapy drugs used in the central nervous system lymphoma therapy: monitoring drug delivery
PublicationOur aim is to optically monitor the delivery of the chemotherapy drugs for brain tumours, particularly used in the central nervous system (CNS) lymphoma therapy. In vivo monitoring would help to optimize the treatment and avoiding unnecessary medications. Moreover, it would be beneficial to be able to measure which of the multi-regimen drugs actually do penetrate and how well into the brain tissue. There exist several potential...
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Is It Right To Predict Cutting Forces On The Basis Of Wood Density?
PublicationSeveral properties of wood can be correlated to wood density. It is widely accepted that the cutting power requirements are following this general assumption. Therefore, according to classic literature sources available for determination of the cutting power for both band- and circular- sawing machines, the cutting power requirements (and/or cutting forces) are computed as a function of the wood specific gravity SG. It was shown...
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Silicon Oxycarbide (SiOC) Ceramic Materials as Anodes for Lithium Ion Batteries
PublicationPolymer derived ceramics (PDCs) have attracted attention as alternative anode material for Li-ion batteries. It has been found that ternary SiOC and SiCN ceramics obtained through pyrolysis of various preceramic polymers display high reversible capacities of 500 – 650 mAh/g. In this work we try to correlate the electrochemical performance of polymer derived silicon oxycarbide with its chemical composition and microstructural features....
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Low-cost multiband compact branch-line coupler design using response features and automated EM model fidelity adjustment
PublicationDesign closure of compact microwave components is a challenging problem because of significant electromagnetic (EM) cross-couplings in densely arranged layouts. A separate issue is a large number of designable parameters resulting from replacement of conventional transmission line sections by compact microstrip resonant cells. This increases complexity of the design optimization problem and requires employment of expensive high-fidelity...
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Unusual Influence of Fluorinated Anions on the Stretching Vibrations of Liquid Water
PublicationInfrared (IR) spectroscopy is a commonly used and invaluable tool in the studies of solvation phenomena in aqueous solutions. Concurrently, ab initio molecular dynamics (AIMD) simulations deliver the solvation shell picture at a molecular detail level and allow for a consistent decomposition of the theoretical IR spectrum into underlying spatial correlations. Here, we demonstrate how the novel spectral decomposition techniques...
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Effect of Polymerization Statistics on the Electronic Properties of Copolymers for Organic Photovoltaics
PublicationStatistical block copolymers, composed of donor (D) and acceptor (A) blocks, are a novel type of material for organic photovoltaics (OPVs) devices. In particular a new series of polymers based on PBTZT-stat-BDTT-8, recently developed by Merck, offers high solubility in different solvents, and a high power conversion efficiency (PCE) in different device architectures. Although it is known that the electronic properties of these...
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Shape-dependent enhanced photocatalytic effect under visible light of Ag3PO4 particles
PublicationSilver phosphate (Ag3PO4) could be considered as visible light induced photocatalyst for pollutants degradation, due to its narrow band gap (∼2.4 eV). However, Ag3PO4 photoactivity depends on surface properties and synthesis route. In this study, differently shaped Ag3PO4 photocatalysts have been synthesized through the precipitation, ion exchange, soft-chemical or hydrothermal method. To correlate surface properties with photoactivity all...
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Charge Transfer, Complexes Formation and Furan Fragmentation Induced by Collisions with Low-Energy Helium Cations
PublicationThe present work focuses on unraveling the collisional processes leading to the fragmentation of the gas-phase furan molecules under the He+ and He2+ cations impact in the energy range 5–2000 eV. The presence of different mechanisms was identified by the analysis of the optical fragmentation spectra measured using the collision-induced emission spectroscopy (CIES) in conjunction with the ab initio calculations. The measurements of...
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Properties of Oxygen Vacancy and Hydrogen Interstitial Defects in Strontium Titanate: DFT + Ud,p Calculations
PublicationThis work presents extensive theoretical studies focused on the mixed ion-electron transport in cubic strontium titanate (STO). A new approach to the description of this difficult system was developed within the framework of linear-scaling Kohn–Sham density functional theory, as realized in the ONETEP program. The description we present is free of any empirical parameters and relies on the Hubbard U and Hund’s J corrections applied...
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Frequency Selective Surface Based MIMO Antenna Array for 5G Millimeter-Wave Applications
PublicationAbstract: In this paper a radiating element consisting of a modified circular patch is proposed for MIMO arrays for 5G millimeter-wave applications. The radiating elements in the proposed 2×2 MIMO antenna array are orthogonally configured relative to each other to mitigate mutual coupling that would otherwise degrade the performance of the MIMO system. The MIMO array was fabri-cated on Rogers RT/Duroid high frequency substrate...
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A spline-based FE approach to modelling of high frequency dynamics of 1-D structures
PublicationIn this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries...
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Neutral Dissociation of Pyridine Evoked by Irradiation of Ionized Atomic and Molecular Hydrogen Beams
PublicationThe interactions of ions with molecules and the determination of their dissociation patterns are challenging endeavors of fundamental importance for theoretical and experimental science. In particular, the investigations on bond-breaking and new bond-forming processes triggered by the ionic impact may shed light on the stellar wind interaction with interstellar media, ionic beam irradiations of the living cells, ion-track nanotechnology,...
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Insight into Potassium Vanadates as Visible-Light-Driven Photocatalysts: Synthesis of V(IV)-Rich Nano/Microstructures for the Photodegradation of Methylene Blue
PublicationPhotocatalysis is regarded as a promising tool for wastewater remediation. In recent years, many studies have focused on investigating novel photocatalysts driven by visible light. In this study, K2V6O16·nH2O nanobelts and KV3O8 microplatelets were synthesized and investigated as photocatalysts. Samples were obtained via the facile method based on liquid-phase exfoliation with ion exchange. By changing the synthesis temperature...
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Microcrystalline Cellulose Management in the Production of Poly(ether-urethane)s- Structure, Morphology, and Thermal Characteristic
PublicationIn response to the demand of polymer industry for reducing the use of synthetic chemicals, eco-friendly materials are investigated. In the presented study, bio-based poly(ether-urethane)s were prepared by using microcrystalline cellulose (MCC) and polyether polyol and 1,3-propanediol derived from corn sugar. A step towards sustainability was taken by incorporating bio-based compounds and cellulose, consequently, bio-waste are utilized...
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Fouling mechanisms in anoxic-aerobic sequencing batch membrane bioreactor based on adapted Hermia models and main foulant characteristics
PublicationVarious derivatives of Hermia models (complete pore blocking, intermediate pore blocking, cake layer formation, and standard pore blocking) and different assessments of foulant characteristics have long been used to determine the membrane fouling mechanisms. Accordingly, this study aims to adapt Hermia models and their combination according to the operating conditions of an anoxic-aerobic sequencing batch membrane bioreactor (A/O-SBMBR)....
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Nodal models of Pressurized Water Reactor core for control purposes – A comparison study
PublicationThe paper focuses on the presentation and comparison of basic nodal and expanded multi-nodal models of the Pressurized Water Reactor (PWR) core, which includes neutron kinetics, heat transfer between fuel and coolant, and internal and external reactivity feedback processes. In the expanded multi-nodal model, the authors introduce a novel approach to the implementation of thermal power distribution phenomena into the multi-node...
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Integration and Visualization of the Results of Hydrodynamic Models in the Maritime Network-Centric GIS of Gulf of Gdansk
PublicationEnsuring of security in the coastal area makes on a seaside countries research in the field of infrastructure spatial information of environmental data. The paper presents the results of work on the construction of this infrastructure by integrating electronic navigational chart with ortophotomaps of coastal areas as well as numerical data from weather and hydrodynamic models. Paper focuses on a problems associated with creating...
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Public Perception of Digital Contact Tracing App and Implications for Technology Acceptance and Use Models
PublicationGovernments are increasingly adopting digital contact tracing applications (DCT) as a key component of their response to the COVID-19 pandemic. However, governments are struggling to achieve widespread adoption of DCT necessary for obtaining the expected individual and public benefits associated with its use. Consequently, studies on DCT have focused on the barriers to DCT adoption in different contexts and possible ways of overcoming...
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Band structure, Born effective charges, and lattice dynamics of CuInS2 from ab initio calculations
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Selected properties and parameters of radio channel impulse response estimation in ISM 2.4 GHz band
PublicationThe article presents experimental research indicating that the impulse response of the communication channel, determined in practice, are not of an universal character, but only represent its approximate value for the frequency on which this measurement was made. Phases for each of the replicas of the measurement signal were determined during the analysis of the received signals in the baseband. Phase changes of individual replicas...
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Forecasting values of cutting power for the sawing process of impregnated pine wood on band sawing machine
PublicationW artykule przedstawiono prognozowane wartości mocy skrawania dla pilarki taśmowej (ST100R firmy STENNER), które są stosowane w polskich tartakach. Wartości mocy skrawania oszacowano dla drewna sosny zwyczajnej (Pinus sylvestris L.), które zostało poddane impregnacji. Dla porównania wyznaczono również wartości mocy skrawania dla drewna niezaimpregnowanego. Wartości te określono za pomocą innowacyjnej metody prognozowania sił skrawania,...
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A gap waveguide-based mechanically reconfigurable phase shifter for high-power Ku-band applications
PublicationThis paper presents a novel design of a low-loss, reconfgurable broadband phase shifter based on groove gap waveguide (GGW) technology. The proposed phase shifter consists of a folded GGW and three bends with a few pins forming the GGW and one bend attached to a movable plate. This movable plate allows for adjustments to the folded waveguide length, consequently altering the phase of electromagnetic waves. The advantage of GGW...
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New Type of Small Broad-Band Internal Antenna for Third Generation Mobile Phone Handsets.
PublicationW pracy przedstawiono nową szerokopasmową antenę łatową przeznaczoną dla telefonów komórkowych trzeciej generacji. Proponowana struktura zawiera obwód (rezonator) w kształcie litery U i zaliczana jest do klasy PIFA (planar inverted-F antenna). W trakcie procesu projektowania przeprowadzono szereg symulacji elektromagnetycznych (metoda momentów), których wyniki zweryfikowano w oparciu o pomiary charakterystyk wykonanego prototypu....
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Microfluidic SIW-Based Tunable Self-Diplexing Antenna for Sub-6 GHz Band Applications
PublicationThis work introduces a novel frequency tunable self-diplexing antenna (SDA) design based on substrate integrated waveguide (SIW) technology. A modified A-shaped slot is employed on the cavity’s top plane, which is excited by two independent 50 Ω microstrip feed lines to operate at each resonant frequency. The frequency flexibility of the proposed antenna allows for fine-tuning at each resonance frequency. The frequency flexibility...
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Application examples of wide area monitoring for system operators withinh UCTE = Zastosowanie technologii WAMS w systemie UCTE
PublicationRozrost geograficzny systemów elektroenergetycznych zwiększa prawdopodobieństwo wystąpienia słabo tłumionych kołysań elektromechanicznych. W artykule omawia się zastosowanie systemu WAMS w celu wykrywania tego typu zjawisk i dalej w celu ich eliminacji.
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Proposal of edge-area form removal of cylindrical surfaces containing wide dimples by application of various robust processing techniques
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COMPARATIVE ANALYSIS OF RESULTS OF APPLICATION OF MARKOV AND SEMI-MARKOV PROCESSES TO RELIABILITY MODELS OF MULTI-STATE TECHNICAL OBJECTS
PublicationDuring rational operation of technical objects and systems various operational decisions are made and decision-making process itself should be consisted in selecting that considered most favourable out of all possible to be taken. Choice of such decision is possible after taking into account many different information items but it never be completely correct without accounting for data and indices dealing with reliability. In...
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Influence of service ageing on polyester-reinforced polyvinyl chloride-coated fabrics reported through mathematical material models
PublicationIn this paper the coupled service (constructional tension) and environmental (sunlight, rainfalls, temperature variations) ageing influence on the polyester-reinforced polyvinyl chloride (PVC)-coated fabric VALMEX is studied. Two cases of the same fabric have been analyzed: one USED for 20 years on the real construction of the Forest Opera in Sopot (Poland), and one kept as a spare material (NOT USED). The following tests have...
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Empirical analysis of tree-based classification models for customer churn prediction
PublicationCustomer churn is a vital and reoccurring problem facing most business industries, particularly the telecommunications industry. Considering the fierce competition among telecommunications firms and the high expenses of attracting and gaining new subscribers, keeping existing loyal subscribers becomes crucial. Early prediction of disgruntled subscribers can assist telecommunications firms in identifying the reasons for churn and...
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Genetic and pharmacologic proteasome augmentation ameliorates Alzheimer’s-like pathology in mouse and fly APP overexpression models
PublicationThe proteasome has key roles in neuronal proteostasis, including the removal of misfolded and oxidized proteins, presynaptic protein turnover, and synaptic efficacy and plasticity. Proteasome dysfunction is a prominent feature of Alzheimer’s disease (AD). We show that prevention of proteasome dysfunction by genetic manipulation delays mortality, cell death, and cognitive deficits in fly and cell culture AD models. We developed...
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Efficient Surrogate Modeling and Design Optimization of Compact Integrated On-Chip Inductors Based on Multi-Fidelity EM Simulation Models
PublicationHigh-performance and small-size on-chip inductors play a critical role in contemporary radio-frequency integrated circuits. This work presents a reliable surrogate modeling technique combining low-fidelity EM simulation models, response surface approximations based on kriging interpolation, and space mapping technology. The reported method is useful for the development of broadband and highly accurate data-driven models of integrated...
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The effect of sunscreen 4‐methylbenzylidene camphor in different and reproductive models, its bioaccumulation and molecular effects on ligand‐receptor interaction, and protein expression
Publication4-Methylbenzylidene camphor (4-MBC) is a photo-absorbing UV filter prevalently used in cosmetics, which can be absorbed into circulation and cause systemic effects. 4-MBC is continued to be released in the environment despite the growing knowledge about its bioaccumulation and endocrine disrupting effects. Previous reviews have mentioned UV-filter together but this review considers 4-MBC alone, due to its prevalence and concerning...