criterion method
Recently Published Documents


TOTAL DOCUMENTS

112
(FIVE YEARS 29)

H-INDEX

14
(FIVE YEARS 3)

Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 269
Author(s):  
Ismail Mohamed ◽  
Yaser Dalveren ◽  
Ferhat Ozgur Catak ◽  
Ali Kara

In the development of radiofrequency fingerprinting (RFF), one of the major challenges is to extract subtle and robust features from transmitted signals of wireless devices to be used in accurate identification of possible threats to the wireless network. To overcome this challenge, the use of the transient region of the transmitted signals could be one of the best options. For an efficient transient-based RFF, it is also necessary to accurately and precisely estimate the transient region of the signal. Here, the most important difficulty can be attributed to the detection of the transient starting point. Thus, several methods have been developed to detect transient start in the literature. Among them, the energy criterion method based on the instantaneous amplitude characteristics (EC-a) was shown to be superior in a recent study. The study reported the performance of the EC-a method for a set of Wi-Fi signals captured from a particular Wi-Fi device brand. However, since the transient pattern varies according to the type of wireless device, the device diversity needs to be increased to achieve more reliable results. Therefore, this study is aimed at assessing the efficiency of the EC-a method across a large set of Wi-Fi signals captured from various Wi-Fi devices for the first time. To this end, Wi-Fi signals are first captured from smartphones of five brands, for a wide range of signal-to-noise ratio (SNR) values defined as low (−3 to 5 dB), medium (5 to 15 dB), and high (15 to 30 dB). Then, the performance of the EC-a method and well-known methods was comparatively assessed, and the efficiency of the EC-a method was verified in terms of detection accuracy.


2022 ◽  
pp. 149-156
Author(s):  
A. M. Fadeeva

The article presents a solution to the problem of integrating risk minimisation methods in the process of forming the optimal range of treadmill models in a retail enterprise. The problem of multi-criteria optimisation was solved using the generalised criterion method. The formulated problem was therefore broken down into a number of specific tasks, each of which was solved by selecting specific methods. Risks were minimised by mathematical methods, taking into account the economic performance of the enterprise. Recommendations were also offered for customers wishing to purchase one of the treadmill models chosen from the analysis and the best option for ordering via the online shop with home delivery. 


2021 ◽  
Vol 904 ◽  
pp. 387-391
Author(s):  
Ramiro Correa-Jaramillo ◽  
Berenice Zúñiga-Torres ◽  
Alonso Zúñiga-Suárez ◽  
Francisco Hernández-Olivares ◽  
Israel Briceño-Tacuri

The calcined clay bricks are the second most used materials in construction that, after the demolition processes, tends to become rubble, generating a negative visual and environmental impact, in addition to the fact that the brick-making process has not been industrialized in Ecuador, for that, its properties are deficient; in this way, the present research aims to study the physical, chemical and mineralogical characteristics of brick waste from the Southern part of ​​this country, for the elaboration of ecological bricks through geopolymerization processes, using as alkaline activator Sodium Hydroxide at temperature ranged between 90 °C and 200 °C, obtaining an optimal mixture at the combination 12.5 M, 26 wt% Cs, 150 °C. The mechanical properties of bricks as simple compression and flexural strength, respectively, applying the experimental Griffith criterion method by finite element simulation method. These ecological bricks obtained are suitable for use in construction.


Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 5) ◽  
Author(s):  
Liang Zhang ◽  
Linchao Yang ◽  
Songhe Geng ◽  
Shaoran Ren

Abstract Based on the principle of wellbore self-circulation heat mining, the evaluation experiments of local wellbore self-circulation heat exchange laws and influencing factors were carried out. Water, SCCO2, R134a, and heat transfer oil were screened as the heat-carrying fluids. The heat exchange laws and heat mining capacity of these four heat carrying fluids were analyzed and compared, and their heat mining rates at the field scale were estimated using the similarity criterion method according to the experimental results. The results show that R134a and heat transfer oil can obtain the largest outlet temperature and the largest heat loss ratio, while the water can achieve a higher heat mining rate and a larger convective heat transfer coefficient than the other three fluids. The heat mining capacity of CO2 is significantly affected by the injection pressure. It is necessary to optimize the injection pressure larger than critical point to achieve the best heat mining performance. When the water is selected as the heat-carrying fluid, the heat mining rate can reach more than 1 MW if a horizontal wellbore with a length of 2000 m is applied for wellbore self-circulation at the field scale.


2021 ◽  
Vol 5 (2) ◽  
pp. 55
Author(s):  
Yang Zhao ◽  
Shicun Zhao ◽  
Yi Zhang ◽  
Da Wang

In this paper, a novel escape-time algorithm is proposed to calculate the connectivity’s degree of Julia sets generated from polynomial maps. The proposed algorithm contains both quantitative analysis and visual display to measure the connectivity of Julia sets. For the quantitative part, a connectivity criterion method is designed by exploring the distribution rule of the connected regions, with an output value Co in the range of [0,1]. The smaller the Co value outputs, the better the connectivity is. For the visual part, we modify the classical escape-time algorithm by highlighting and separating the initial point of each connected area. Finally, the Julia set is drawn into different brightnesses according to different Co values. The darker the color, the better the connectivity of the Julia set. Numerical results are included to assess the efficiency of the algorithm.


2021 ◽  
pp. 50-50
Author(s):  
Xu Wu ◽  
Cheng Zhang ◽  
Luojun Yang

In this paper, an improved technique for order of preference by similarity to ideal solution (TOPSIS) is proposed to select the optimal transportation service provider among several alternatives according to a multi-criterion method. An entropy method is embedded to determine the weights of different criteria and it is effective to avoid the subjectivity and arbitrary of choosing the weights. A case study demonstrates the proposed method is reasonable and valid for practical problems.


Author(s):  
V. V. Cherkashуna ◽  
V. M. Baklitsky

Improved technical and economic models of 35–750 kV overhead lines in accordance with the Law of Ukraine "On the Electricity Market" are proposed. The urgency and complexity of the problem is due to the fact that the transition to market relations presupposes the presence of private property, where the area under the grid facility, including the route of overhead lines, is a commodity and should be taken into account in shaping the value of this facility. In this regard, there is a need to review the discounted costs in the design of lines to bring them into line with market relations. The development of a new technical and economic model of 35–750 kV overhead lines was carried out taking into account the size and cost of land under the route of the line, which allows for a feasibility study of the optimal design option for the electrical network. The specific part of the land area in the cost of 1 km of overhead lines of different voltage classes is calculated. The components of the improved technical and economic model of 35–750 kV overhead lines are determined, namely the specific part of the component costs in the total cost of 1 km overhead lines of different voltage classes. A graphical representation of generalized models of investments in 35–750 kV overhead lines is presented. The presented studies take into account that during the construction of technical and economic models it is almost impossible to predict all its internal often stochastic connections, the elements of which cannot be expressed unambiguously, which leads to incomplete source information. Based on this fact, in the article for the analysis of the developed technical and economic models of lines the criterion method which allows to make decisions in conditional units both at full and at incomplete and indefinite initial information is applied. Implementing each equation of the developed technical and economic model of 35–750 kV overhead lines by the criterion method the ratio of components in the optimal design of lines in the corresponding voltage class is obtained, which allows to determine the development strategy of electrical networks and to form restrictions in incomplete source information.


2020 ◽  
pp. 2150111
Author(s):  
Shuheng Qu ◽  
Jinping Li ◽  
Huaiyu Cheng ◽  
Bin Ji

The sheet/cloud cavitating flow always contains complex multiscale vortex structures generated by the cavity cloud shedding and collapsing. In this study, the transient sheet/cloud cavitating flow around a Clark-Y hydrofoil is numerically investigated using the Large Eddy Simulation (LES) method coupled with the Zwart–Gerber–Belamri (ZGB) cavitation model. The simulation accurately reproduces the unsteady cavitation evolution process, and the predicted time-averaged lift and drag coefficients, total vapor volume variation and velocity distribution agree fairly well with the experimental measurements. The cavitation vortex dynamics are studied in detail with different vortex identification methods including the vorticity method, the [Formula: see text]-criterion method, the [Formula: see text] method, the [Formula: see text] method and the Liutex method. The vortex identification ability of the different methods in the transient sheet/cloud cavitating flow is also discussed. Generally, the Liutex method combines the advantages of the other methods and can accurately identify both the vortex position and strength. Further analysis of cavitation-vortex interactions demonstrates that the cavity cloud shedding and collapsing have a pronounced influence on the vortex structure.


Sign in / Sign up

Export Citation Format

Share Document