Wyniki wyszukiwania - BazTech

1

Multi-criteria decision analysis approach for dc microgrid bus selection

Charaabi Foued, Dali Mehdi, Belhadj Jamel

Power Electronics and Drives

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2025

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Vol. 10 (45)

157--175

EN

The increasing variety of DC microgrid configurations has created a challenge for engineers in selecting the optimal design. To address this, multi-criteria decision analysis (MCDA) provides a systematic approach. In this study, six distinct DC microgrid configurations are defined as potential alternatives: unipolar, bipolar, multi-terminal topology, multi-bus topology, ring topology and AC microgrid. MCDA allows for the establishment of relevant evaluation criteria specific to each configuration, such as protection schemes, fault resilience and overall system cost. By systematically analysing the MCDA results using the analytic hierarchy process (AHP) technique, the most suitable DC microgrid design can be identified, which inherently determines the optimal type of distribution bus. AHP assigns weights to each evaluation criterion based on its relative importance. This study concludes with a comprehensive sensitivity analysis and an investigation of optimisation techniques. This assessment integrates perspectives from both expert judgements and relevant scientific publications.

2

Assessment of the vulnerability and sensitivity of groundwater for drinking water supply and irrigation: The case of the Mitidja alluvial aquifer (Northern Algeria)

Khelfi Mohamed El Amine, Hallal Dahbia Djoudar, Guastaldi Enrico, Alili Malika, Nadri Mohamed

Geomatics, Landmanagement and Landscape

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2025

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no. 1

119-145

EN

The aim of this study is to combine the hydrochemical data, geostatistical methods, and numerical approaches with the water pollution vulnerability index of the Mitidja alluvium. This index is obtained by applying the DRASTIC model and a numerical rating system to develop a methodology based on the water sensitivity index. The socio-economic development has led to the overexploitation of groundwater and surface water resources, coupled with insufficient rainfall, which has exacerbated the sensitivity and vulnerability of this precious resource. Compared to previous studies, the most recent sensitivity map serves as an important decision support tool for relevant authorities. According to the survey, this index was very low, accounting for 45.43% of the total drinking water area in 2010. It decreased to 8.25% and later increased to 28.06% in 2018. The high and very high sensitivity index to water pollution (SI) accounted for 5.34% and 9.87% in 2010, and 19.77% and 15.78% in 2018. The variation in irrigation water sensitivity was similar that of drinking water sources (DWS). The medium and high sensitivity indices (SI) increased from 27.21% and 18.20% to 37.19% and 42.01%, reflecting a significant and alarming increase in groundwater sensitivity, vulnerability, and pollution within the study area. The results of the geostatistical approach yielded some interesting results, considering the water intended for drinking water supply and the water intended for irrigation separately in the Mitidja alluvial aquifer.

PL

Celem tego badania jest połączenie danych hydrochemicznych, metod geostatystycznych i podejść numerycznych ze wskaźnikiem podatności na zanieczyszczenie wody aluwium Mitidja. Wskaźnik ten uzyskano poprzez zastosowanie modelu DRASTIC i numerycznego systemu oceny w celu opracowania metodologii opartej na wskaźniku wrażliwości wody. Rozwój społeczno-gospodarczy doprowadził do nadmiernej eksploatacji zasobów wód gruntowych i powierzchniowych, w połączeniu z niewystarczającymi opadami deszczu, co zaostrzyło wrażliwość i podatność tego cennego zasobu. W porównaniu z poprzednimi badaniami najnowsza mapa wrażliwości służy jako ważne narzędzie wspomagające podejmowanie decyzji dla odpowiednich organów. Według badania wskaźnik ten był bardzo niski i stanowił 45,43% całkowitej powierzchni wody pitnej w 2010 r. Zmniejszył się do 8,25%, a następnie wzrósł do 28,06% w 2018 r. Wysoki i bardzo wysoki wskaźnik wrażliwości na zanieczyszczenie wody (SI) stanowił 5,34% i 9,87% w 2010 r. oraz 19,77% i 15,78% w 2018 r. Zmienność wrażliwości wody nawadniającej była podobna do zmienności źródeł wody pitnej (DWS). Średnie i wysokie wskaźniki wrażliwości (SI) wzrosły z 27,21% i 18,20% do 37,19% i 42,01%, co odzwierciedla znaczny i alarmujący wzrost wrażliwości, podatności i zanieczyszczenia wód gruntowych na badanym obszarze. Wyniki podejścia geostatystycznego przyniosły interesujące rezultaty, biorąc pod uwagę osobno wodę przeznaczoną do zaopatrzenia w wodę pitną i wodę przeznaczoną do nawadniania w warstwie wodonośnej aluwialnej Mitidja.

3

Analysing the impact of electric kick-scooters on drivers : vibration and frequency transmission during the ride on different types of urban pavements

Karpenko Mykola, Prentkovskis Olegas, Skačkauskas Paulius

Eksploatacja i Niezawodność

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2025

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Vol. 27, no. 2

art. no. 199893

EN

The purpose of this research is to determine the vertical vibration and frequency spectrum transmitted to the rider by electric scooters travelling on different types of road surfaces. Vibration analysis involves the measurement of vibration levels of e-scooter elements, accompanied by the analysis of the Fourier Transform Spectrum and using a t-sample measurement design and a one-sample statistical method. Approach in the research allows overall driver comfort to be assessed through frequency and vibration analysis, considering vibrations received by the hands and the whole body. In addition, the natural frequencies of the electric scooter components and their stability are being investigated to assess vibration transformation. The study includes an assessment of ride comfort and considers potential health implications. The results obtained facilitate the identification of critical risks associated with vertical vibration frequencies transmitted to individuals when riding electric kick-scooters in urban areas with different types of pavements.

4

Design of localized surface plasmon resonance-based refractive index sensor using optical fiber

Yadav Mukti, Kaler R. S.

Optica Applicata

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2024

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Vol. 54, nr 1

85--96

EN

The paper proposes a design of a localized surface plasmon resonance-based refractive index sensor for the detection of a chemical compound availing unclad geometry of the optical fiber. The geometry is explored to analyze the sensing behavior and coupling phenomenon at the metal-dielectric interface. The finite element method (FEM) is applied numerically to evaluate the analytical change in the reflectance spectra of the fiber model by inoculating potassium nitrate compound. The resonance shift and reflectance of the surface plasmon resonance (SPR) signal obtained after the optimization of structural parameters enhance the sensing performance of the prototype. The sensor exhibits a maximum sensitivity of 80.2919 rad/RIU for a 1.56 high refractive index analyte and minimum sensitivity of 2.3446 rad/RIU for a 1.33 low refractive index analyte. The proposed sensor is modelled in such a way that it can be employed in various sensing applications for a wide range of refractive indices.

5

Applicability of artificial intelligence in smart healthcare systems for automatic detection of Parkinson’s Disease

Pallathadka Harikumar, Padminivalli V. S.J.R.K., Vasavi M., Nancy P., Naved Mohd, Kumar Harish, Ray Samrat

Computer Assisted Methods in Engineering and Science

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2024

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Vol. 31, no. 2

175--185

EN

Parkinson’s disease is associated with memory loss, anxiety, and depression in the brain. Problems such as poor balance and difficulty during walking can be observed in addition to symptoms of impaired posture and rigidity. The field dedicated to making computers capable of learning autonomously, without having to be explicitly programmed, is known as machine learning. An approach to the diagnosis of Parkinson’s disease, which is based on artificial intelligence, is discussed in this article. The input for this system is provided through photographic examples of Parkinson’s disease patient handwriting. Received photos are preprocessed using the relief feature option to begin the process. This is helpful in the process of selecting characteristics for the identification of Parkinson’s disease. After that, the linear discriminant analysis (LDA) algorithm is employed to reduce the dimensions, bringing down the total number of dimensions that are present in the input data. The photos are then classified via radial basis function-support vector machine (SVM-RBF), k-nearest neighbors (KNN), and naive Bayes algorithms, respectively.

6

Nowoczesne małowrażliwe materiały wybuchowe do celów wojskowych

Prasuła Piotr, Gołofit Tomasz, Kasprzak Piotr

Przemysł Chemiczny

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2023

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T. 102, nr 11

1162--1168

PL

Przegląd literatury pod kątem nowoczesnych kruszących materiałów wybuchowych charakteryzujących się obniżoną wrażliwością na bodźce zewnętrzne, w tym bodźce mechaniczne, takie jak uderzenie itarcie. Podano podstawowe właściwości poszczególnych materiałów wybuchowych wraz z parametrami detonacyjnymi, istotnymi z praktycznego punku widzenia. Możliwość wykorzystania danego materiału do celów wojskowych warunkowana jest również kosztami produkcji, co bezpośrednio wiąże się ze stopniem skomplikowania procesu syntezy oraz dostępnością niezbędnych odczynników chemicznych.

EN

A review, with 66 refs., of modern explosives, characterized by reduced sensitivity to external stimuli, including mech. ones, such as impact and friction. The basic properties of individual explosives responsible for reducing sensitivity to external stimuli and detonation parameters important from a practical point of view were given. These factors det. whether a given material or an explosive compn. based on it will find practical application.

7

The Numerical Analysis of the Elementary, Fractional Order, Interval Transfer Function

Oprzędkiewicz Krzysztof

Pomiary Automatyka Robotyka

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2023

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R. 27, nr 4

45--51

EN

In the paper the analysis of the impact of the interval uncertainty of parameters on the behaviour of the elementary Fractional Order (FO) transfer function is investigated. The fractional order and quasi time constant are defined as intervals describing deviation from nominal values. Such an analysis has not be considered yet. The proposed elementary, interval model can be applied in modeling of different, uncertain-parameters elements and physical phenomena. For the considered transfer function the methodology of its numerical analysis is proposed and illustrated by simulations. Results of numerical tests point that the best robustness of the model is achieved for relatively lower values of its parameters.

PL

W pracy zaprezentowano analizę wpływu przedziałowej niepewności parametrów na zachowanie się elementarnej transmitancji niecałkowitego rzędu. Parametry modelu: rząd ułamkowy i pseudo-stała czasowa są zdefiniowane jako przedziały opisujące odchyłki od wartości nominalnych. Tego typu analiza nie była do tej pory rozważana. Proponowany elementarny model przedziałowy może znaleźć zastosowanie do opisu różnych elementów i zjawisk fizycznych, dla których wartości parametrów są opisane jedynie w sposób przybliżony. Dla rozważanej transmitancji zaproponowano metodologię jego analizy numerycznej i zilustrowano ją symulacjami. Wyniki testów numerycznych wskazują, że model jest najbardziej odporny na niepewność parametrów dla ich relatywnie niskich wartości.

8

Optical simulations and optimization of highly sensitive biosensor for cancer cell detection

El Mouncharih Abdelkarim, Takassa Rabi, Farkad Omar, Tchenka Abdelaziz, Ibnouelghazi El Alami, Abouelaoualim Driss

Optica Applicata

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2023

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Vol. 53, nr 3

407--418

EN

In this work, using the two-dimensional finite difference time domain method, we are theoretically studying the optical properties of a two-dimensional photonic crystal biosensor based on silicon rods arranged as a square structure in an air bottom with two waveguides and a nanocavity. For this purpose, six different cells are infiltrated into the point defect. These six cells are Jurkat, HeLa, PC-12, MDA-MB-231, MCF-7, and basal cells. As a result, we have successfully detected cancer and benign cases of these cells through resonance peaks in the transmission spectrum. We evaluated the sensitivity, quality factor, detection limit, and figure of merit at different values for sensing region radius for optimization purposes. We report that we observed the maximum sensitivity of 1350 nm/RIU at 0.15 μm for the basal cell. Finally, the proposed biosensor can be a miniaturized structure with extreme sensitivity in cancer cell detection models.

9

An extrinsic Fabry–Pérot interference fiber sensor for ultrasonic detection of partial discharge

Zhang Ximin, Qian Sen, Liu Huixin, Chen Chuan, Deng Chuanlu, Hu Chengyong, Huang Yi

Optica Applicata

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2023

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Vol. 53, nr 2

199--211

EN

An ultrasonic sensor based on extrinsic Fabry–Pérot interference (EFPI) has been designed and demonstrated to detect the ultrasonic wave signal. The sensitivity and natural frequency of fiber Fabry–Pérot (F-P) sensor with different structure parameter have been simulated by COMSOL. The simulation results illustrate that the sensitivity is up to 1.737 nm/kPa and the natural frequency is 2.1 MHz, when the silica diaphragm thickness is 2 μm, the radius is 90 μm, and the cavity length is 18 μm. The most suitable parameters have been selected and the F-P sensor has been fabricated. When the ultrasonic signals with the frequencies of 40 kHz and 1.2 MHz are respectively applied to the sensor, the frequencies detected by the EFPI ultrasonic sensor are 39 kHz and 1.21 MHz based on a partial discharge detection experiment for the designed demodulation system. The experimental results show that the sensor can accurately detect ultrasonic signals. As an excellent platform for ultrasonic signal sensing, this EFPI ultrasonic sensing system has great potential applications in partial discharge detection field.

10

Dynamic tilt testing of MEMS inclinometers based on conical motions

Yang Qihang, Cai Chenguang, Yang Ming, Kong Ming, Liu Zhihua, Liang Feng

Metrology and Measurement Systems

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2023

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Vol. 30, nr 1

31--47

EN

The MEMS inclinometer integrates a tri-axis accelerometer and a tri-axis gyroscope to solve the perceived dynamic inclinations through a complex data fusion algorithm, which has been widely used in the fields of industrial, aerospace, and monitoring. In order to ensure the validity of the measurement results of MEMS inclinometers, it is necessary to determine their dynamic performance parameters. This study proposes a conical motion-based MEMS inclinometer dynamic testing method, and the motion includes the classical conical motion, the attitude conical motion, and the dual-frequency conical motion. Both the frequency response and drift angle of MEMS inclinometers can be determined. Experimental results show that the conical motions can accelerate the angle drift of MEMS inclinometers, which makes them suitable for dynamic testing of MEMS inclinometers. Additionally, the tilt sensitivity deviation of the MEMS inclinometer by the proposed method and the turntable-based method is less than 0.26 dB. We further provide the research for angle drift and provide discussion.

11

Device for measurement and control of humidity in crude oil and petroleum products

Semenov Andriy, Zviahin Oleksander, Kryvinska Natalia, Semenova Olena, Rudyk Andrii

Metrology and Measurement Systems

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2023

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Vol. 30, nr 1

195--208

EN

A device with a frequency-modulated output signal has been developed to increase the sensitivity and accuracy of measuring moisture content in crude oil and petroleum products in the range of 0~20%. The main element of the device is a self-oscillator transducer based on a transistor structure with negative differential resistance. A capacitive sensor in the form of a capacitive cylindrical structure with cylindrical electrodes was used to determine moisture content in crude oil and petroleum products. Electric permittivity of a two-component mixture of oil and water was estimated and the capacitance of the humidity-sensitive capacitive cylindrical structure with cylindrical electrodes was calculated. An electrical diagram of the device for measuring and controlling the humidity of crude oil and petroleum products has been developed. The relative error of converting the humidity of oil and petroleum products into capacitance which was caused by the change in oil temperature, was determined to be 0.225%. Values of relative errors of the device for measuring the humidity of oil and petroleum products are as follows: 1.355 · 10-5% is caused by instability of the oscillator frequency, 0.01% is caused by fluctuations in the supply voltage of the self-oscillator transducer, 0.05% is caused by a change in ambient temperature by 1°C. For the developed device, which used errors of the first and second type, the reliability of humidity control of oil and petroleum products has been determined to be 0.9591.

12

Investigating the impact of isolation, self-isolation and environmental transmission on the spread of COVID-19: Case study in Rwanda

Lubuma Jean M.-S., Tassé Arsène Jaures Ouemba, Signing Francis, Tsanou Berge

Mathematica Applicanda

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2023

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Vol. 51, no. 2

239--271

EN

In this work, we propose a ten-compartmental COVID-19 model with human to human and environment to human transmissions. A notational feature of this model is the consideration of the infected who escape from the self–isolation and later spread the disease. The model is rigorously analysed both theoretically and numerically. From the mathematical point of view, we prove that the disease-free equilibrium is globally asymptotically stable when the basic reproduction number R is less than one, that is the disease dies out. When R is greater than one, we prove that the model admits a unique endemic equilibrium, locally asymptotically stable, meaning that the disease would persist, at least inside the basin of attraction of the endemic equilibrium. The sensitivity analysis of the model highlights that the environmental transmission is the most influent parameter, which leads in an increasing number of infected individuals whenever it increases. The model is calibrated using the daily cumulative asymptomatic cases in Rwanda reported from the 1 April 2022 to the 14 June 2022. We found that the basic reproduction number is equal to 0.6479 and most infected people in Rwanda during this period of time are asymptomatic. We investigate the impact of isolation and self-isolation to reduce the disease burden, and both sensitivity analysis and numerical analysis show that the isolation has more effect on the dynamics of the infected than the self-isolation. We also prove that, the individuals who escape from the self-isolation, contribute, but weakly to the increasing of the number of infected individuals.

PL

W niniejszej pracy proponujemy dziesiecioprzedzialowy model COVID19 z transmisja z czlowieka na czlowieka i ze środowiska na człowieka. Istotną cechą tego modelu jest uwzglednienie zarażonych, którzy uciekają z samoizolacji, a następnie rozprzestrzeniają chorobę. Model jest rygorystycznie analizowany zarówno teoretycznie, jak i numerycznie. Z matematycznego punktu widzenia udowadniamy, że stan wolny od choroby jest globalnie asymptotycznie stabilna, gdy Rav0av jest mniejsze niz jeden, czyli choroba wymiera. Gdy Rav jest wieksze niz jeden, udowadniamy, że model dopuszcza unikalną równowagę endemiczna, lokalnie asymptotycznie stabilną, co oznacza , że choroba utrzyma się, przynajmniej wewnatrz basenu przyciągania równowagi endemicznej. Analiza wrażliwości modelu podkreśla, że transmisja środowiskowa jest najbardziej wpływowym parametrem, który prowadzi do rosnącej liczby zarażonych osobników, gdy tylko wzrasta. Nasz model został skalibrowany przy użyciu dziennych skumulowanych przypadków bezobjawowych w Rwandzie zgłoszonych od 1 kwietnia 2022 do 14 czerwca 2022. Stwierdziliśmy, że współczynnik odnowienia choroby jest równy 0, 6479, a wiekszość zarazonych osób w Rwandzie w tym okresie jest bezobjawowa. Badamy wpływ izolacji i samoizolacji w celu zmniejszenia obciążenia chorobą, a zarówno analiza wrażliwosci, jak i analiza numeryczna pokazują, ze izolacja ma większy wpływ na dynamikę infekcji niż samoizolacja.

13

Evaluation of Modular J-PET sensitivity

Tayefi Ardebili Faranak, Niedźwiecki Szymon, Moskal Paweł

Bio-Algorithms and Med-Systems

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2023

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Vol. 19, no. 1

132--138

EN

The Modular J-PET represents the latest advancement in the Jagiellonian-PET series, utilizing extended plastic scintillator strips. This prototype's modular design enables cost-effective imaging of multi-photon annihilation and positronium, allowing for easy assembly, portability, and versatility. Additionally, its lightweight construction facilitates static bed examinations with a mobile detection system that can be positioned conveniently alongside the patient, negating the requirement for spacious clinical settings. Comprising 24 modules arranged in regular 24-sided polygons circumscribing a 73.9 cm diameter circle, each module integrates 13 scintillator strips, measuring 50 cm in length and 6 mm × 24 mm in cross-section. Scintillation light is captured at both ends through analog Silicon Photomultipliers (SiPMs). This research presents Sensitivity of the Modular J-PET tomograph, adhering to the NEMA_NU 2-2018 standards. Sensitivity measurement was performed with 68Ge line source inside the 5 sleeves aluminium phantom placed at center of the detector`s field-of-view (FOV) and 10 cm offset from the center of detector. Analyzing the gathered data involved employing the specialized J-PET Framework software, developed within the C++ architecture. To validate the experimental findings, comparisons were made with GATE simulations, wherein the source and phantom were emulated in the same configuration as employed in the actual experiment. The system sensitivity of the Modular J-PET was assessed to be 1.03 ± 0.02 cps/kBq in the center of the detector`s FOV with the peak sensitivity of 2.1 cps/kBq. However, the simulations indicate that at the center of the detector's FOV, the Modular J-PET achieves a system sensitivity of 1.32 ± 0.03 cps/kBq, with a peak sensitivity of 2.9 cps/kBq.

14

Implicit neural state functions in hybrid reliability analysis of plane frame

Potrzeszcz-Sut Beata, Dudzik Agnieszka, Radoń Urszula

Archives of Civil Engineering

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2023

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Vol. 69, nr 4

55--71

EN

The objective of the article involves presenting innovative approach to the assessment of structural reliability analysis. The primary research method was the First Order Reliability Method (FORM). The Hasofer-Lind reliability index in conjunction with transformation method in the FORM was adopted as the reliability measure. The implicit limit state functions were used in the analysis. The formulation of the random variables functions were created in the Matlab software by means of neural networks (NNs). The reliability analysis was conducted in Comrel module of Strurel computing environment. In the proposed approach, Hybrid FORM method (HF) used the concept in which NNs replaced the polynomial limit state functions obtained from FEM (Finite Elements Method) for chosen limit parameters of structure work. The module Comrel referenced Matlab files containing limit state functions. In the reliability analysis of structure, uncertain and uncorrelated parameters, such us base wind speed, characteristic snow load, elasticity modulus for steel and yield point steel are represented by random variables. The criterion of structural failure was expressed by four limit state functions - two related to the ultimate limit state and two related to the serviceability limit state. Using module Comrel values of the reliability index with the FORM method were determined. Additionally, the sensitivity of the reliability index to random variables and graph of partial safety factors were described. Replacing the FEM program by NNs significantly reduces the time needed to solve the task. Moreover, it enables the parallel formulation of many limit functions without extending the computation time.

PL

Obecnie ocena niezawodności konstrukcji bazuje na wyidealizowanej koncepcji stanów granicznych i ich weryfikacji poprzez zastosowanie częściowych współczynników bezpieczeństwa. Rolą częściowych współczynników bezpieczeństwa jest zapewnienie wymaganego poziomu niezawodności konstrukcji. Metody probabilistyczne są naturalnym rozszerzeniem metody stanów granicznych. W praktycznych zastosowaniach istniejące oprogramowanie MES (Metoda Elementów Skończonych) jest często łączone z modułami do analizy niezawodności. Wadą takiego podejścia jest jednak długi czas obliczeń wynikający z wielokrotnych wywołań funkcji stanu granicznego dla różnych realizacji wektora zmiennych losowych. W artykule autorzy proponują alternatywne rozwiązanie problemu poprzez implementację hybrydowej metody FORM. Ocenę prawdopodobieństwa awarii, a tym samym obliczenie wskaźnika niezawodności Hasofera-Linda, uzyskujemy poprzez zastosowanie metody aproksymacyjnej FORM. W analizie wykorzystano niejawne funkcje stanów granicznych. Formułowanie funkcji granicznych dla pewnego zakresu zmiennych losowych zostało utworzone w programie Matlab za pomocą sieci neuronowych (SN). Analiza niezawodności została przeprowadzona w module Comrel środowiska obliczeniowego Strurel. Pakiet ten zawiera wbudowane interfejsy do definiowania funkcji stanów granicznych umożliwiając odwołanie do plików Matlaba zawierających zdefiniowane przez użytkownika funkcje stanu. Proponowana przez autorów hybrydowa metoda FORM łączy trzy algorytmy obliczeniowe - metodę elementów skończonych, sieci neuronowe oraz metodę aproksymacyjną probabilistycznej oceny niezawodności konstrukcji - FORM. Struktura algorytmu systemu jest więc mieszana, tzn. szeregowo-równoległa. Analiza zadania przebiega w czterech etapach.

15

An Innovative Drastic Metric for Ranking Similarity in Decision-Making Problems

Sałabun Wojciech, Shekhovtsov Andrii

Annals of Computer Science and Information Systems

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2023

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Vol. 35

731--738

EN

In this paper, we propose a novel approach to distance measurement for rankings, introducing a new metric that exhibits exceptional properties. Our proposed distance metric is defined within the interval of 0 to 1, ensuring a compact and standardized representation. Importantly, we demonstrate that this distance metric satisfies all the essential criteria to be classified as a true metric. By adhering to properties such as non-negativity, identity of indiscernibles, symmetry, and the crucial triangle inequality, our proposed distance metric provides a robust and reliable approach for comparing rankings in a rigorous and mathematically sound manner. Finally, we compare our new metric with distances such as Hamming distance, Canberra distance, Bray-Curtis distance, Euclidean distance, Manhattan distance, and Chebyshev distance. By conducting simple experiments, we assess the performance and advantages of our proposed metric in comparison to these established distance measures. Through these comparisons, we demonstrate the superior properties and capabilities of our new drastic weighted similarity distance for accurately capturing the dissimilarities and similarities between rankings in the decision-making domain.

16

Investigation of aquifer vulnerability and sensitivity analysis of modified drastic and sintacs models: a case study of Ovogovo Area, Eastern Nigeria

Omeje Emmanuel T., Obiora Daniel N., Okeke Francisca N., Ibuot Johnson C., Ugbor Desmond O., Omeje Victor D.

Acta Geophysica

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2023

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Vol. 71, no. 5

2439--2464

EN

Groundwater serves as a useful source of freshwater to man. Its protection and assessment of potential exposure to contamination are imperative, as its remediation when contaminated is extremely challenging. Vertical electrical sounding was carried out in twenty (21) locations of Ovogovo area with the aim to evaluate the vulnerability of groundwater to pollution, using four vulnerability indexed-based models. Results from DRASTIC AND SINTACS models delineated low and moderate vulnerable zones, while DRASTICLu and SINTACSLu, establishing an index range of 177 to 191 and 160 to 174, respectively, delineated eleven (11) locations as highly vulnerable to contamination. The four models characterized six locations as moderately vulnerable. Statistical summary of DRASTICLu and SINTACSLu models identified high risk of aquifer contamination to originate from recharge and soil media, with a very low risk of contamination, emanating from nature of vadose zone, aquifer nature, topography and land use. Results from single parameter sensitivity and map removal analysis for the modified models delineated depth to water table and land use as the most sensitive parameters in vulnerability assessment of Ovogovo area. Single or multiple map removal analysis identified an increment in sensitivity to vulnerability index as more parameters were being removed. The integration of these vulnerability models and sensitivity analysis enhanced good interpretation of the estimated vulnerable zones. These results will serve as a guide to governmental and non-governmental bodies in understanding the Ovogovo groundwater vulnerability characteristics and sensitization of habitants against indiscriminate disposal of waste and other harmful contaminants for preservation of its groundwater.

17

Sensitivity of Aerodynamic Characteristics of Paraglider Wing to Properties of Covering Material

Maślanka Paulina, Korycki Ryszard

Autex Research Journal

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2022

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Vol. 22, no. 1

64--72

EN

The paper is theoretically oriented. The main goal is to analyze the sensitivity of aerodynamic characteristics to the properties of the material used for paraglider wing. The paraglider of considerable dimensions is designed without stiffening elements. Thus, the covering material yields adequate pressure distribution between the external and internal parts of the wing. The problem is solved using a geometrical model approximated by the dimensionless coordinates of crucial points and smoothed by spline curves. The finite volume mesh is defined using the Ansys Meshing program. Numerical analysis uses five different covering materials, ranging from the air-impermeable covering to the covering subjected to hydrolytic-mechanical degradation. Optimization of properties of the covering material improves the lift force and the aerodynamic characteristics of the wing. Moreover, numerical modeling is more beneficial and efficient than prototype tests. The obtained pressure distributions and other parameters explain the aerodynamic safety of the paraglider during dynamic conditions of flight.

18

A review of the current state-of-the-art in Fano resonance-based plasmonic metal-insulator-metal waveguides for sensing applications

Adhikari R., Chauhan D., Mola G. T., Dwivedi R. P.

Opto-Electronics Review

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2021

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Vol. 29, No. 4

148--166

EN

Fano resonance is an optical effect that emerges from the coherent coupling and interference (constructive and destructive) between the continuous state (background process) and the Lorentzian state (resonant process) in the plasmonic waveguide-resonator system. This effect has been used in the applications like optical sensors. These sensors are extensively used in sensing biochemicals and gases by the measurement of refractive index changes as they offer high sensitivity and ultra-high figure of merit. Herein, we surveyed several plasmonic Fano sensors with different geometries composed of metal-insulator-metal waveguide(s). First, the resonators are categorized based on different architectures. The materials and methods adopted for these designs are precisely surveyed and presented. The performances are compared depending upon the characterization parameters like sensitivity and figure of merit. Finally, based on the survey of very recent models, the advances and challenges of refractive index sensing deployed on Fano resonances are discussed.

19

Investigations on the luminescence properties of quartz and feldspars extracted from loess in the Canterbury Plains, New Zealand South Island

Brezeanu D., Avram A., Micallef A., Cinta Pinzaru S., Timar-Gabor A.

Geochronometria

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2021

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Vol. 48, no.1

46--60

EN

The applicability of the single-aliquot regenerative-dose (SAR) protocol, by using the optically stimulated luminescence (OSL) signal of quartz as well as the post-infrared–infrared (pIRIR) signals of polymineral fine grains, namely pIRIR225 and pIRIR290, was assessed for dating loess in New Zealand South Island. OSL signals of quartz grains displayed low sensitivity. However, the application of repeated irradiation/bleaching cycles did not result in an increase in sensitivity; annealing in the 300–500°C temperature range generated the sensitisation of both the 110°C thermoluminescence (TL) peak as well as the OSL signal, likely by activation of yet unidentified luminescence centres. After heating, the quartz signal is comparable to that of ideal samples, but the annealing is precluding successful dating. On the other hand, feldspar infrared-stimulated signals displayed satisfactory properties, allowing estimation of ages ranging from 14 ± 1–29 ± 3 ka for the investigated deposit. It was shown that pIRIR225 and pIRIR290 methods have potential for dating loess in the South Island of New Zealand, based on the following observations: (i) Dose recovery tests were successful with recovered-to-given dose ratios with a <10% deviation from unity, (ii) constant residual values of about 4 Gy and about 10 Gy were obtained after exposures for 48 h in the case of pIRIR225 signals and 96 h in the case of pIRIR290 signals, respectively, (iii) while a slight dose-dependence of the residual was reported, and for a dose as large as 1600 Gy the residual values are ≅9 Gy and ≅19 Gy for pIRIR225 and pIRIR290 signals, respectively.

20

Progress and perspectives in total body PET systems instrumentation

Vandenberghe Stefaan

Bio-Algorithms and Med-Systems

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2021

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Vol. 17, no. 4

265--267

EN

Total body positron emission tomography (PET) systems are being developed by different groups worldwide. These systems have potential to change the number of applications in which molecular imaging is used. The change from a short axial field of view (FOV) to a longer one is however associated with a linear increase in the cost of these systems. This may limit their application to a small number of centers (capable of obtaining sufficient research funding). Therefore it remains interesting to see if lower cost systems can be developed and bring total body PET to the clinic for an acceptable budget. The wider availability of this low cost system can also enable more researchers to further optimize and explore the full potential of total body PET.