change intensity
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Electronics ◽  
2021 ◽  
Vol 10 (23) ◽  
pp. 2890
Author(s):  
Heba G. Mohamed ◽  
Fadwa Alrowais ◽  
Dalia H. ElKamchouchi

Security standards have been raised through modern multimedia communications technology, which allows for enormous progress in security. Modern multimedia communication technologies are concerned with fault tolerance technique and information security. As a primary method, there is widespread use of image encryption to protect image information security. Over the past few years, image encryption has paid more attention to combining DNA technologies in order to increase security. The objective here is to provide a new method for correcting color image encryption errors due to the uncertainty of DNA computing by using the fractional order hyperchaotic Lorenz system. To increase randomness, the proposed cryptosystem is applied to the three plain image channels: Red, Green, and Blue. Several methods were compared including the following: entropy, correlation, key sensitivity, key space, data loss attacks, speed computation, Number of Pixel changing rate (NPCR), and Unified Average Change Intensity randomness (UACI) tests. Consequently, the proposed scheme is very secure against a variety of cryptographic attacks.


2021 ◽  
Vol 15 (4) ◽  
pp. 118-131
Author(s):  
Sadiq A. Mehdi

In this paper, a novel four-dimensional chaotic system has been created, which has characteristics such as high sensitivity to the initial conditions and parameters. It also has two a positive Lyapunov exponents. This means the system is hyper chaotic. In addition, a new algorithm was suggested based on which they constructed an image cryptosystem. In the permutation stage, the pixel positions are scrambled via a chaotic sequence sorting. In the substitution stage, pixel values are mixed with a pseudorandom sequence generated from the 4D chaotic system using XOR operation. A simulation has been conducted to evaluate the algorithm, using the standardized tests such as information entropy, histogram, number of pixel change rate, unified average change intensity, and key space. Experimental results and performance analyses demonstrate that the proposed encryption algorithm achieves high security and efficiency.


Wood Research ◽  
2021 ◽  
Vol 66 (4) ◽  
pp. 544-555
Author(s):  
DENES VARGA ◽  
LASZLO TOLVAJ ◽  
EDINA PREKLET

Black locust (Robinia pseudoacacia L.), beech red heartwood (Fagus sylvaticaL.) and spruce (Picea abiesKarst.) wood samples were treatedin saturated steam at 100, 110 and 120°C then irradiated using a UV emitter mercury lamp in order to test their colour stability. Colour change was evaluated and presented in the CIE Lab colour coordinate system. Untreated black locust, beech and spruce specimens as control samples were irradiated using the same mercury lamp. Results revealed that beech produced the greatest colour stability during both steam treatment and the following UV treatment while spruce was the most sensitive species to photodegradation. Steaming reduced the colour change intensity only for black locust during photodegradation. Both redness and yellowness change demonstrate this colour stability increase. Steaming at 120°C resulted in the greatest protection against the colour alteration of black locust caused by photodegradation.The investigated thermal treatments did not change the photodegradation properties of beech and spruce specimens. A considerable increase in colour saturation of the specimens was generated by steaming, and the saturation value further increased during the UV treatment.


2021 ◽  
Author(s):  
Zbigniew Chmielewski

The paper presents a new method of forecasting the durability of piston-rings-cylinder (PRC) liner assembly of the internal combustion engine on the basis of observed changes of physical and chemical properties of engine oil. Methods used so far for the durability evaluation of the PRC group required collecting information about the moments when the assembly reached its boundary state or used kinetic models of wear designed using accelerated research of real objects. In the proposed method, for the evaluation of durability of engine cylinders information gathered form engine oil is used. Course of changes of the proposed index of change intensity of kinematic viscosity at the temperature of 100°C – Cv100 allows for evaluation of the durability of PRC assembly of an IC engine. Obtained value was positively verified using forecasting method related to the technical criteria based on the assessment of the wear intensity.


Entropy ◽  
2021 ◽  
Vol 23 (5) ◽  
pp. 535
Author(s):  
Karim H. Moussa ◽  
Ahmed I. El Naggary ◽  
Heba G. Mohamed

Multimedia wireless communications have rapidly developed over the years. Accordingly, an increasing demand for more secured media transmission is required to protect multimedia contents. Image encryption schemes have been proposed over the years, but the most secure and reliable schemes are those based on chaotic maps, due to the intrinsic features in such kinds of multimedia contents regarding the pixels’ high correlation and data handling capabilities. The novel proposed encryption algorithm introduced in this article is based on a 3D hopping chaotic map instead of fixed chaotic logistic maps. The non-linearity behavior of the proposed algorithm, in terms of both position permutation and value transformation, results in a more secured encryption algorithm due to its non-convergence, non-periodicity, and sensitivity to the applied initial conditions. Several statistical and analytical tests such as entropy, correlation, key sensitivity, key space, peak signal-to-noise ratio, noise attacks, number of pixels changing rate (NPCR), unified average change intensity randomness (UACI), and others tests were applied to measure the strength of the proposed encryption scheme. The obtained results prove that the proposed scheme is very robust against different cryptography attacks compared to similar encryption schemes.


2021 ◽  
Author(s):  
Anjun Lan ◽  
Zemeng Fan ◽  
Qingsong Zhao ◽  
Xuyang Bai

Abstract How to explicitly understanding the soil erosion intensity change in different geomorphological types is one of key issues in the field of soil and water conservation. According to classification criterion of soil erosion intensity of China, the spatial soil erosion data with the resolution of 10 m×10m in Guizhou Province were obtained by combing with the multi-resolution remote sensing data of ALOS, ZY-3, GF-1, Landsat and GDEMV2, and 2762 field sampling data in 2010 and 2015, respectively. a spatial analysis model of soil erosion was improved to analyze the spatiotemporal change of soil erosion intensity in karst and non karst area of Guizhou province, which involved the spatial soil erosion data and different geomorphological type data of Guizhou province. The results show that the soil erosion intensity decreased by 6468.13km 2 in Guizhou Province from 2010 to 2015. The dynamic change intensity in the high-altitude area is larger than in the low-altitude area. The soil change intensity in karst area is higher than in non karst area, especially in the high and middle elevation area in Guizhou province. Moreover, the decreasing ratio of soil erosion intensity in karst area is generally larger than in non karst area, which can be used to explain that the ecological restoration projects and water soil conservation polices carried out in karst area has a good effect, especially in western of Guizhou province from 2010 to 2015, one the other hand, the soil erosion in non karst area should also be focused by local government in the future.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  

Purpose This paper aims to review the latest management developments across the globe and pinpoint practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings This research paper concentrates on the relationship between an employee experiencing job insecurity and their level of adaptive performance (AP). The results revealed a negative link between job insecurity and AP only where core tasks remain in a state of low change intensity. However, where a high state of change was present, an insignificant link between job insecurity and AP was unexpectedly observed. Yet this finding should be used as justification to keep employees working in perpetual states of high change, since this predictably risks eroding their well-being. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.


Author(s):  
Мария Игоревна Быкова ◽  
Николай Дмитриевич Вервейко ◽  
Светлана Евгеньевна Крупенко ◽  
Александр Иванович Шашкин ◽  
Софья Александровна Шашкина

В ближайшей окрестности вершины плоской трещины, а в общем случае, вблизи передней кромки пространственной трещины, деформирование материала носит неупругий характер. В работе предложено лучевое моделирование высокоскоростного деформирования материала в δ-окрестности подвижной передней кромки трещины, используя динамическую упруговязкопластическую модель тела Бингама с условием пластичности Мизеса. Показано, что распространяющаяся передняя кромка трещины продольного сдвига лежит на поверхности сильного разрыва продольной скорости, бегущей со скоростью упругих продольных волн, а передняя кромка трещины отрыва и трещины поперечного сдвига лежит на поверхности сдвиговой волны, бегущей со скоростью волн сдвига. Введены интенсивности передних кромок трещин: скачок скорости сдвига поперек передней кромки трещины продольного сдвига, скачок поперечной скорости на передней кромке трещины отрыва, скачок касательной скорости к передней кромке трещины поперечного сдвига. Построены обыкновенные дифференциальные уравнения переноса интенсивностей передних кромок трещин вдоль лучей как ортогональных траекторий точек переднего фронта. Получены приближенные решения уравнений переноса интенсивностей передних кромок пространственных трещин в напряженный материал и приведены выражения для глубины проникания пространственных трещин. Показано изменение направления сдвига и отрыва в передних кромках соответствующих трещин в зависимости от напряженного состояния перед трещинами. Приведены графики численных расчетов переноса интенсивностей передних кромок трещин и глубины их проникания. In the near neighborhood of the top of the plane crack, and in General, in the space case, near the edge of the spatial crack, the deformations of the material have the inelastic character. In this article proposes the elasticviscoplastic model of the Bingham body with the condition of plasticity of Mises for modeling high velocity deformation material near of the top of crack. Shown that an edge of crack belong a surface of elastic wave: cracks of longitudinal shear belong of longitudinal wave and a crack of untiplane shear and avulsion belong a surface of shear wave. For intensity of the crack suggest a shock velocity on the curve of the edge of crack and made ordinary differential equation for transfer intensity of crack on the front of the wave. Shown that a distant of propagation edge of the crack depend from plastic deformation material on the front of the wave. In the process of propagation crack this direction of shear can change from a stresses in front of the wave. Three-D graphics show change intensity of the crack in a process of propagation from parameters.


PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244084
Author(s):  
Zhiming Sun ◽  
Xianglong Chen ◽  
Hanfa Xing ◽  
Hongtao Ma ◽  
Yuan Meng

Regional differences in socioeconomic factors are important for assessing the regional development of an area. While much research has focused on the overall patterns of regional differences within independent cities and areas, the hierarchical spatiotemporal structures of megacity regions have seldom been discussed. To fill this gap, this paper investigates the multilevel regional differences within megacity regions. Employing GDP, population and total retail sales as socioeconomic indicators, the spatiotemporal patterns of socioeconomic trends are identified. A hierarchical clustering approach that utilizes socioeconomic similarities is proposed for the identification of the spatiotemporal patterns of individual cities. At the megacity regional level, gravity centers and pathways are constructed to evaluate spatial imbalances and temporal change intensities. Taking the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as its study area, this research produces results that show diverse spatiotemporal patterns among the individual cities, revealing high/low starting point and high/low growth rate modes in terms of city interactions. From the perspective of the entire GBA, the spatial imbalance of GDP is the highest of the factors, followed by the spatial imbalance of the total retail sales of the region and, finally, by that of its population. Total retail sales exhibit the highest level of temporal change intensity, followed by GDP and population. In terms of the contribution of the various cities to the overall regional changes, Guangzhou, Shenzhen and Hong Kong dominate the spatiotemporal changes in the gravity centers, while Foshan and Dongguan show significant potential to contribute to these socioeconomic patterns. These results provide effective guidance for the sustainable development of megacity regions.


2020 ◽  
Vol 2020 ◽  
pp. 1-22
Author(s):  
Jorge Aguilar Santiago ◽  
Octavio Flores Siordia ◽  
José T. Guillen Bonilla ◽  
Juan C. Estrada Gutiérrez ◽  
María G. González Novoa ◽  
...  

In this article, a safe communication system is proposed that implements one or more portable devices denominated SBC (single-board computers), with which photographs are taken and that later utilizes the OpenCV Library for the detection and identification of the faces that appear in them. Subsequently, it consults the information in a stored database, whether locally in SBC or in a remote server, to verify that the faces should be coded, and it encrypts these, implementing a new cryptosystem that executes mathematical models to generate chaotic orbits, one of which is used for application on two occasions the technique of diffusion with the purpose of carrying out a small change in one of the pixels of the image, generating very different cryptograms. In addition, in order to make a safer system, it implements other chaotic orbits during the technique of confusion. With the purpose of verifying the robustness of the encryption algorithm, a statistical analysis is performed employing histograms, horizontal, vertical, and diagonal correlation diagrams, entropy, number of pixel change rate (NPCR), unified average change intensity (UACI), sensitivity of the key, encryption quality analysis, and the avalanche effect. The cryptosystem is very robust in that it generates highly disordered cryptograms, supports differential attacks, and in addition is highly sensitive to changes in the pixels as well as in the encrypted keys.


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