Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.9
N. Djaa, M. Djaa
In this paper, we establish necessary and sufficient conditions under which a vector field be biharmonic on the Riemannian manifold. We also construct some examples of proper biharmonic vector fields from a resolution of differential equations.
{"title":"Some results on proper biharmonic vector field","authors":"N. Djaa, M. Djaa","doi":"10.31926/but.mif.2023.3.65.1.9","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.9","url":null,"abstract":"In this paper, we establish necessary and sufficient conditions under which a vector field be biharmonic on the Riemannian manifold. We also construct some examples of proper biharmonic vector fields from a resolution of differential equations. \u0000","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76150070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.13
T. Ozdin
In [8, Theorem 1], Jain and Prasad obtained a kind of symmetry of regular rings which is interesting and useful in the theory of shorted operators (cf. [9]). We show that this symmetry property indeed holds for endomorphism rings of Leavitt path algebras. Using this property, we analyze a (strong/weak) regular inverse of an element of the regular endomorphism ring A of the Leavitt path algebra L:= LK(E) (viewed as a right L-module). We also introduce some partial orders on the endomorphism ring A of the Leavitt path algebra L and investigate the behavior of regular elements in A.
{"title":"Operators on regular rings of Leavitt path algebras","authors":"T. Ozdin","doi":"10.31926/but.mif.2023.3.65.1.13","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.13","url":null,"abstract":"In [8, Theorem 1], Jain and Prasad obtained a kind of symmetry of regular rings which is interesting and useful in the theory of shorted operators (cf. [9]). We show that this symmetry property indeed holds for endomorphism rings of Leavitt path algebras. Using this property, we analyze a (strong/weak) regular inverse of an element of the regular endomorphism ring A of the Leavitt path algebra L:= LK(E) (viewed as a right L-module). We also introduce some partial orders on the endomorphism ring A of the Leavitt path algebra L and investigate the behavior of regular elements in A.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88086915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.15
T. Barbu
An overview of the edge detection techniques based on partial differential equations (PDE) is presented in this work. Nonlinear anisotropic diffusion-based boundary extraction approaches, like the influential Perona- Malik model and some improved variants of it, are described first. Anisotropic diffusion-based detection schemes using the mean curvature motion and nonlinear PDE-based approaches combining anisotropic diffusion to the bilateral filter are then discussed here. Some nonlinear reaction-diffusion-based edge detection methods are described next. Variational edge detection solutions using the total variation (TV) regularization or combining the anisotropic diffusion to the TV-based models are then presented. Directional diffusion-based image edge extraction algorithms are also discussed. Our own contributions in this computer vision domain are finally described.
{"title":"Edge detection techniques using nonlinear diffusion-based models","authors":"T. Barbu","doi":"10.31926/but.mif.2023.3.65.1.15","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.15","url":null,"abstract":"An overview of the edge detection techniques based on partial differential equations (PDE) is presented in this work. Nonlinear anisotropic diffusion-based boundary extraction approaches, like the influential Perona- Malik model and some improved variants of it, are described first. Anisotropic diffusion-based detection schemes using the mean curvature motion and nonlinear PDE-based approaches combining anisotropic diffusion to the bilateral filter are then discussed here. Some nonlinear reaction-diffusion-based edge detection methods are described next. Variational edge detection solutions using the total variation (TV) regularization or combining the anisotropic diffusion to the TV-based models are then presented. Directional diffusion-based image edge extraction algorithms are also discussed. Our own contributions in this computer vision domain are finally described.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72695579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.12
Y. Guo, H. Jiang
We call a ring R a generalized uniquely clean (or GUC for short) if every not invertible element in R is uniquely clean. Let R be a ring. It is shown that R is GUC if and only if it is a local ring or a uniquely clean ring. Thus the GUC ring is a generalization of the local ring. Some basic properties of GUC rings are proved.
{"title":"Rings in which not invertible elements are uniquely clean","authors":"Y. Guo, H. Jiang","doi":"10.31926/but.mif.2023.3.65.1.12","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.12","url":null,"abstract":"We call a ring R a generalized uniquely clean (or GUC for short) if every not invertible element in R is uniquely clean. Let R be a ring. It is shown that R is GUC if and only if it is a local ring or a uniquely clean ring. Thus the GUC ring is a generalization of the local ring. Some basic properties of GUC rings are proved.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72549345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.11
O. Golbasi, E.K. Sogutku
Let R be a prime ring with center Z, I a nonzero ideal of R and D: R × R → R a symmetric bi–(α, α)-derivation and d be the trace of D. In the present paper, we have considered the following conditions: i) [d(x), x]α,α = 0, ii)[d(x), x]α,α ⊆ Cα,α, iii)(d(x), x)α,α = 0, iv)D1(d2(x), x) = 0, v)d1(d2(x)) = f(x), for all x, y ∈ I, where D1 and D2 are two symmetric bi-(α, α)-derivations, d1, d2 are the traces of D1, D2 respectively, B: R × R → R is a symmetric bi-additive mapping, f is the trace of B.
{"title":"Notes on symmetric bi-(α,α)-derivations in rings","authors":"O. Golbasi, E.K. Sogutku","doi":"10.31926/but.mif.2023.3.65.1.11","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.11","url":null,"abstract":"Let R be a prime ring with center Z, I a nonzero ideal of R and D: R × R → R a symmetric bi–(α, α)-derivation and d be the trace of D. In the present paper, we have considered the following conditions: i) [d(x), x]α,α = 0, ii)[d(x), x]α,α ⊆ Cα,α, iii)(d(x), x)α,α = 0, iv)D1(d2(x), x) = 0, v)d1(d2(x)) = f(x), for all x, y ∈ I, where D1 and D2 are two symmetric bi-(α, α)-derivations, d1, d2 are the traces of D1, D2 respectively, B: R × R → R is a symmetric bi-additive mapping, f is the trace of B.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"118 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85721172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.16
Ivan S. Gavrilov
This document represents possible algorithms and methods for the analysis, optimization, and control of wireless sensor networks. The main goal of the work is to find the optimal implementation of the particle swarm optimization method for solving the problem of improving the energy consumption of such networks. The result of the work is a software package for simulating WSN (Wireless sensor network) networks using all the methods of routing and optimization of WSN networks presented in the work. The usage of a combination of routing schemes and different systems of device state management raises the wireless sensor network lifetime and reduces the power consumption of the network. The developed and presented in the work network simulator allows any developer to design and test different network topologies with various network parameters. Such software will make it easy to design such networks both for large enterprises and independent developers.
{"title":"Development of a wireless sensor network simulator using energy-efficient traffic routing methods","authors":"Ivan S. Gavrilov","doi":"10.31926/but.mif.2023.3.65.1.16","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.16","url":null,"abstract":"This document represents possible algorithms and methods for the analysis, optimization, and control of wireless sensor networks. The main goal of the work is to find the optimal implementation of the particle swarm optimization method for solving the problem of improving the energy consumption of such networks. The result of the work is a software package for simulating WSN (Wireless sensor network) networks using all the methods of routing and optimization of WSN networks presented in the work. The usage of a combination of routing schemes and different systems of device state management raises the wireless sensor network lifetime and reduces the power consumption of the network. The developed and presented in the work network simulator allows any developer to design and test different network topologies with various network parameters. Such software will make it easy to design such networks both for large enterprises and independent developers.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74780586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.7
E. K. Çetinalp, O. Deveci, N. Yilmaz
In this paper, firstly, we define the k-step generalized Balancing sequences and study the Binet formula of these sequences. Also, we find families of super-diagonal matrices such that the permanents of these matrices are the elements of the k-step generalized Balancing sequences. Finally, we examine the periods of the k-step Balancing sequences in the semi-direct product presented by G = < x, y | x2m−1 = y2 = 1, yxy = x−1 > for the generating pair (x, y).
{"title":"A study of the k-step generalized balancing sequences","authors":"E. K. Çetinalp, O. Deveci, N. Yilmaz","doi":"10.31926/but.mif.2023.3.65.1.7","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.7","url":null,"abstract":"In this paper, firstly, we define the k-step generalized Balancing sequences and study the Binet formula of these sequences. Also, we find families of super-diagonal matrices such that the permanents of these matrices are the elements of the k-step generalized Balancing sequences. Finally, we examine the periods of the k-step Balancing sequences in the semi-direct product presented by G = < x, y | x2m−1 = y2 = 1, yxy = x−1 > for the generating pair (x, y).","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80448116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.8
Adina Chirilă
We analyze viscoelastic porous materials in the coupled linear theory. We consider the coupling between the volume fraction and Darcy’s law for a right cylinder. The mathematical model is represented by a system of equations of steady vibrations for the displacement vector, the changes in the volume fraction, and the pressure. The spatial behavior is characterized in terms of some cross-sectional functions.
{"title":"Spatial behaviour in the coupled theory for viscoelastic materials with voids","authors":"Adina Chirilă","doi":"10.31926/but.mif.2023.3.65.1.8","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.8","url":null,"abstract":"We analyze viscoelastic porous materials in the coupled linear theory. We consider the coupling between the volume fraction and Darcy’s law for a right cylinder. The mathematical model is represented by a system of equations of steady vibrations for the displacement vector, the changes in the volume fraction, and the pressure. The spatial behavior is characterized in terms of some cross-sectional functions.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"60 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77893240","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.14
A. Abdolahzadeh, M. Aman, J. Tayyebi
This paper investigates a combinatorial optimization interdiction problem, called bottleneck spanning tree interdiction. This problem is a game containing two players with conflicting goals. The first player, called the user, wants to find a bottleneck (min-max or max-min) spanning tree in a weighted network. The other player called the attacker, increases edge weights under a budget constraint as well as bound constraints so that the user does not achieve his/her goal. This game has a hierarchy structure. It means that the attacker first perturbates the network and then, the user chooses his/her strategy after observing the attacker’s action. This paper considers the problem in two cases there are fixed and linear costs for the attacker. Two divide-and-conquer algorithms are developed to solve the problem under both costs in polynomial time.
{"title":"Bottleneck spanning tree interdiction problem with fixed and linear costs","authors":"A. Abdolahzadeh, M. Aman, J. Tayyebi","doi":"10.31926/but.mif.2023.3.65.1.14","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.14","url":null,"abstract":"This paper investigates a combinatorial optimization interdiction problem, called bottleneck spanning tree interdiction. This problem is a game containing two players with conflicting goals. The first player, called the user, wants to find a bottleneck (min-max or max-min) spanning tree in a weighted network. The other player called the attacker, increases edge weights under a budget constraint as well as bound constraints so that the user does not achieve his/her goal. This game has a hierarchy structure. It means that the attacker first perturbates the network and then, the user chooses his/her strategy after observing the attacker’s action. This paper considers the problem in two cases there are fixed and linear costs for the attacker. Two divide-and-conquer algorithms are developed to solve the problem under both costs in polynomial time.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"36 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76654244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.31926/but.mif.2023.3.65.1.6
D. Bouagada, A. Faraoun
The aim of this work is the application of the Sumudu transform for solving singular continuous-time linear systems based on the conformable derivative operator. Thanks to the interesting properties of the conformable Sumudu transform that we have established, a new approach is developed. Through academic and real examples, our method is compared to the existing ones, where the applicability and the accuracy of the developed process are shown.
{"title":"State-space solution of singular linear continuous-time systems using the conformable derivative and Sumudu transform","authors":"D. Bouagada, A. Faraoun","doi":"10.31926/but.mif.2023.3.65.1.6","DOIUrl":"https://doi.org/10.31926/but.mif.2023.3.65.1.6","url":null,"abstract":"The aim of this work is the application of the Sumudu transform for solving singular continuous-time linear systems based on the conformable derivative operator. Thanks to the interesting properties of the conformable Sumudu transform that we have established, a new approach is developed. Through academic and real examples, our method is compared to the existing ones, where the applicability and the accuracy of the developed process are shown.","PeriodicalId":53266,"journal":{"name":"Bulletin of the Transilvania University of Brasov Series V Economic Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88005457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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