Sohrabali Ghorbanian; Hossein Abolghasemi; Seyyed Mohammad Ali Mousavian
Abstract
In this research paper, an experimental breakthrough curve for citric acid in an adsorption recovery process was determined by an ion-exchange resin in 20, 35, 55 °C. Also, a mathematical model for breakthrough curve was presented. Among ion exchange resins that have been experienced, many weak and ...
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In this research paper, an experimental breakthrough curve for citric acid in an adsorption recovery process was determined by an ion-exchange resin in 20, 35, 55 °C. Also, a mathematical model for breakthrough curve was presented. Among ion exchange resins that have been experienced, many weak and strong basic anionic resins are available such as, IRA-92, IRA-93, IRA-420 and IRA-458 and all of them were experienced in this work. It was shown that IRI-93 has good performance and compatibility. To obtain concentration of citric acid in the outlet stream from the resin glass column, spectrophotometer UV-VIS, Cary 1E/ Cary 3E from Varian Company was used. The results indicated weak basic kinds are suitable for organic acids recovery, especially for citric acid. Also, the results showed that Amberlite IRA-93 is one of the best resins for recovery of citric acid. In the transient state adsorption, the breakthrough isothermal adsorption curve was obtained in different temperatures. Generally, although an increase in temperature causes an increase in diffusion coefficient of particles, the saturation capacity of resin (or the effective adsorption of acid in the bed) decreases. Several models in different forms, such as fractional, polynomial and exponential, were developed and with analyzing these models a new mathematical model in the form of and modified form of were developed for prediction of the breakthrough curve with low error. Also, if the model is to be used for the break through curve between start and terminal rapture points, the situation of fitting is in the best condition and error less than 1% could be achieved. In this way, least square method in Eviews software was applied. With using these models, the variation of similar breakthrough curves could be fitted, appropriately.
Ali Reza Azmoudeh Ardalan; Hassan Hashemi Farahani
Abstract
Using satellite altimetry derived mean sea level (MSL), geopotential coefficients in terms of ellipsoidal harmonics from recent satellite gravimetry missions, gravity potential values over a grid consisting of 33,486 points at global sea areas are computed and the mean value of the gravity potential ...
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Using satellite altimetry derived mean sea level (MSL), geopotential coefficients in terms of ellipsoidal harmonics from recent satellite gravimetry missions, gravity potential values over a grid consisting of 33,486 points at global sea areas are computed and the mean value of the gravity potential at MSL is calculated as a new geoid’s potential value. In this way we have exactly followed the Gauss-Listing definition of geoid for computation of geoid’s potential value and arrived at the value as the main product of this study. Knowing, (1) coordinates of the grid points over MSL, (2) the geoid’s potential value, and (3) the potential values at the MSL, made it possible to compute the potential difference between MSL and geoid potential value, which was next transformed into height difference via Bruns formula to arrive at Sea Surface Topography (SST) and a global marine geoid as the second and third products of the study.
Shabnam Shahbazi; Abdorrahim Javaherian; Mojtaba Mohammadoo Khorasani
Abstract
Geological facies interpretation is essential for reservoir studying. The method of classification and identification seismic traces is a powerful approach for geological facies classification and distinction. Use of neural networks as classifiers is increasing in different sciences like seismic. They ...
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Geological facies interpretation is essential for reservoir studying. The method of classification and identification seismic traces is a powerful approach for geological facies classification and distinction. Use of neural networks as classifiers is increasing in different sciences like seismic. They are computer efficient and ideal for patterns identification. They can simply learn new algorithms and handle the nonlinearity of seismic data. They are often reliable with noisy data or atypical environments. In this paper, an approach is presented based on competitive neural network for classification and identification of the reservoir facies that uses seismic trace shape. The competitive networks can be applied on discrete facies. Its unsupervised methods are independent on the wells data and other auxiliary information. Its supervised methods are independent on the wells location. This approach can be performed in two ways. In first way, the seismic facies are classified based on entirely on the characteristics of the seismic responses, without requiring the use of any well information. It is implemented by a single layer competitive unsupervised neural network, called Kohonen self organized neural network. In the second way, automatic identification and labeling of the facies is performed by the use of seismic responses and wells data. It is implemented by a two layer competitive supervised neural network, called Learning Vector Quantizer (LVQ) neural network. The results of both analyses on artificial seismic section and actual seismic section of the sixth zone of Asmary formation in Shadegan oilfield showed reservoir facies distribution and predicted heterogeneity of their characteristics.
Vahid Tavakkoli; Abdolhossein Amini
Abstract
Well logs are principal sources of subsurface geological information. They provide significant information on mineralogical composition, texture, sedimentary structures and petrophysical properties such as porosity and permeability. By compiling data from various well logs, one can discriminate sedimentary ...
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Well logs are principal sources of subsurface geological information. They provide significant information on mineralogical composition, texture, sedimentary structures and petrophysical properties such as porosity and permeability. By compiling data from various well logs, one can discriminate sedimentary units with comparable log characteristics. Sedimentary units with similar fluid flow and capacity are named rock type. Rock type determination is the most important task in reservoir characterization of oil bearing formations. Rock type may be determined using different data sets but their definition on the basis of wire line logs is most common. Multivariate cluster analysis (as the best method of data grouping) is one of the most accurate and effective methods in oil bearing reservoir zonation. The method is applied on both detrital and carbonates rocks. This method gets more support by improvements in algorithms and statistics. Proper combination of logs and appropriate algorithm will increase the accuracy, reliability and effect of the method. Similar faces may have different log responses due to diverse factors that affect the logs. Since using statistical methods and procedures are mandatory, in clustering procedure data are grouped with minimum distance and maximum homogeneity. It is obvious that distinct geological parameters can be related to a group of data, which are to be used by geologists for further interpretation. For this calculation, all log readings are considered as "observations" and the used logs as the "values of the observations".
There are several ways to compute the distance between objects. The "Standardized Euclidean" distance is used here in form the MATLAB software, because more accurate results are obtained with this procedure. By grouping log data in multidimensional space (equal dimensions with number of logs), each point (reading) can be related to a group of data (rock type). High resolution rock typing with reliable conclusions can be inferred with this procedure using pure mathematical formula in which there is no need to regression equations or trainings. In this method, any geological parameter described from other sources such as cores and thin sections can be related to wells with comparable rock types. The accuracy and reliability of defined rock types can be examined in wells from which suitable cores are available. Results from such a comparison provide a fundamental base for study of wells with poor core and cutting data.
Using MATLAB software, this study testifies a new simple method for rock type determination of Asmari Formation in Marun Field. The reliability of the method is examined by correlation of the resultant rock types with those of inferred from cores. Result from such a correlation indicates the reliability of method in rock type determination.
Seyyed Abdollah Kianejad; Hamid Ebadi; Masoud Varshosaz; Barat Mojarradi
Abstract
By far, many stereo-matching techniques have been successfully proposed and applied in digital aerial photogrammetry. However, due to some problems such as large parallaxes, occlusions, geometric deformations, and repetitive patterns in convergent close range images, these methods may not be applicable ...
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By far, many stereo-matching techniques have been successfully proposed and applied in digital aerial photogrammetry. However, due to some problems such as large parallaxes, occlusions, geometric deformations, and repetitive patterns in convergent close range images, these methods may not be applicable to the same level of success as that of aerial imagery. In order to overcome these shortcomings, in this paper a new hybrid area and feature-based image matching method is proposed. This technique, puts the emphasis on spectral information of color images without the need for prior knowledge about imaging conditions such as overlap and order of images. This method was implemented and tested on real close range images having different convergence angles. The results showed that it succeeds in convergent images with angles about 40-60 degrees giving an accuracy of 2 pixels.
Kianoush Karimi; Reza Attarnejad
Abstract
In this paper, time-domain dynamic analysis of dam - infinite reservoir is studied. A numerical method, discrete singular convolution (DSC), which seems to be efficient and simple, has been used to model the mixed boundary conditions. After a brief introduction, DSC is applied to model the equation of ...
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In this paper, time-domain dynamic analysis of dam - infinite reservoir is studied. A numerical method, discrete singular convolution (DSC), which seems to be efficient and simple, has been used to model the mixed boundary conditions. After a brief introduction, DSC is applied to model the equation of motion of fluid-structure with constant cross section subjected to El-Centro (1940) earthquake. To show the accuracy and reliability of DSC method, the results have been compared with the Lee & Tsai method as a benchmark. The results show the competency of the proposed method to model Dam-Reservoir systems.
Farhad Kolahan; Mohammad Doustparast; Mojtaba Mamourian
Abstract
In this research, a model for optimal PM planning based on reliability is developed and solved for multi-component systems. In the proposed model, the type of PM actions for each inspection period is determined in such manner that the total weighted related costs are minimized while a minimum required ...
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In this research, a model for optimal PM planning based on reliability is developed and solved for multi-component systems. In the proposed model, the type of PM actions for each inspection period is determined in such manner that the total weighted related costs are minimized while a minimum required system reliability is maintained. The planning horizon is divided into some inspections intervals of equal size. In the beginning of each interval, with respect to the system constraints, one of the following PM actions is suggested for each component: 1) inspection and minimal service, 2) preventive repair and 3) preventive replacement. Each of these activities consumes different resources and has different effect on the system reliability. The PM costs include, repair cost, replacement cost, system downtime cost, and random failure cost. In the optimal PM schedule, the PM actions are determined so that a minimum required reliability is obtained with minimum total PM cost. Since the proposed model has a complex structure, Tabu Search and Simulated Annealing are employed to provide quick solutions. The efficiency of these techniques has been demonstrated by solving a PM scheduling problem for a system with 14 components.
Mohammad Farough Hosseini; Hossein Mahmoudi Dovvom Niasar; Morteza Ahmadi; Vahid Sa'ati
Abstract
Gotvand dam is a rock fill dam located in Khoozestan province in Iran on Karun River. It will be constructed on weak mudstone and layers of sandstone. These layers are intermittent of medium strength with uniaxial compressive strength of 15 and 25MPa respectively. Some regional factors as continuous ...
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Gotvand dam is a rock fill dam located in Khoozestan province in Iran on Karun River. It will be constructed on weak mudstone and layers of sandstone. These layers are intermittent of medium strength with uniaxial compressive strength of 15 and 25MPa respectively. Some regional factors as continuous unloading, caused by river flood washed off and horizontal tectonic loading have created a local anticline in the base of the dam. It is estimated that such deformation will last over the time. Therefore, in order to determine creep parameters assessing the time dependent behavior of the foundation rock during the life of the dam through numerical and analytical methods is inevitable. In this research, by conducting creep tests under constant loads the strain- time graphs were produced for the two rock types. Applying the Burger rheological model for both rocks, their creep parameters were determined. In order to validate the produced data numerical modeling was conducted. A comparison between the results of numerical modeling and laboratory tests showed that the difference between the two methods is less than 6%. Also the time required for both rocks to enter the tertiary creep was determined to be 40 days for sandstone under 17.72MPa and 35 days for mudstone under 7.8MPa of load.
Hamid Reza Bakhshi; Azar Mahmoud Zadeh
Abstract
One of the important issues in many of array systems such as Radar, Sonar, Mobile, and satellite telecommunications is the estimation of DOA of narrowband received signal. CRB is very important in evaluation of parameter estimation. CRB is the lower bound estimation error variance for any unbiased estimation. ...
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One of the important issues in many of array systems such as Radar, Sonar, Mobile, and satellite telecommunications is the estimation of DOA of narrowband received signal. CRB is very important in evaluation of parameter estimation. CRB is the lower bound estimation error variance for any unbiased estimation. In this paper, the array antenna with equal distance arrays is extended in two separated subarrays. At first we study the lower bound of estimation error variance for Direction-of-Arrival in array antennas using CRB method. Then, with extending the above method, the estimation error variance for Direction-of-Arrival in array antennas with two separated subarrays is computed. It is observed that if the size of array increases, the estimation accuracy also increases. But the cost of array and complication of the system also increase. Therefore, we suggest using array antennas with separated subarrays. Furthermore, when signal to noise ratio in the communications system is low, by using of array antennas with two separated subarrays, the Direction-of-Arrival is estimated with high accuracy.
Simulation results show that as the distance between the two subarrays and the distance between the antennas increase, the estimation error variance decreases. It should be noted that the distance between antennas should not be more than wavelength of received signal. This causes the ambiguity in estimation and grows up the sidelobes
Parna Shabestari; Mohammad Hossein Kahaei
Abstract
Determination of mobile localization with time of arrival (TOA) signal is a requirement in cellular mobile communication. In some of the previous methods, localization with non-line-of-sight (NLOS) paths can lead to large position error. Also for simplicity, in most simulations suppose non stationary ...
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Determination of mobile localization with time of arrival (TOA) signal is a requirement in cellular mobile communication. In some of the previous methods, localization with non-line-of-sight (NLOS) paths can lead to large position error. Also for simplicity, in most simulations suppose non stationary actual environments as stationary. This paper proposes (residual test + recursive least square) ((RT+RLS)) that has a good application in non stationary environments. In this algorithm, residual test (RT) that can simultaneously determine the number of line- of-sight (LOS) base stations (BSs) and identify them. In simulation studies, the RT can determine the correct number of LOS-BS over 90% of the time. Then using TOA signals obtain these BSs as input of RLS algorithms and estimate mobile position in high attention and low calculation.
Ghasem Dehghani Eshkezari; Ali Akbar Aghakouchak; Mehrdad Kokabi
Mohammad Shekarchizadeh; Farhad Porgar
Homayoun Oraizi; Narges Nouri
Abstract
With the rapid growth of indoor wireless communication systems, the need to accurately model radio wave propagation inside the building environments has increased. Many site-specific methods have been proposed for modeling indoor radio channels. Among these methods, the ray tracing algorithm and the ...
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With the rapid growth of indoor wireless communication systems, the need to accurately model radio wave propagation inside the building environments has increased. Many site-specific methods have been proposed for modeling indoor radio channels. Among these methods, the ray tracing algorithm and the finite-difference time domain (FDTD) method are the most popular ones. The ray tracing approach as a high frequency technique is efficient for calculating the received field at a small number of receiver locations. Application of FDTD method as a full wave technique for indoor propagation modeling is time consuming and requires large amounts of memory. The parabolic equation method (PEM) is a fast full-wave technique which allows accurate modeling of the propagation environment and its electrical parameters. This paraxial version of the wave equation can be solved by marching techniques which need far less computation resources than a full elliptic equation. The PEM has been extensively used as an efficient algorithm for outdoor propagation modeling. In this paper we propose an unprecedented application of PEM for indoor propagation problems. Depending on the required speed and accuracy of computations, two and three-dimensional versions of the PEM can be used for indoor problems. Without loss of generality, we restrict ourselves to the two-dimensional problems and use two-dimensional approximation of the parabolic equation for fast and accurate radio wave propagation modeling in indoor environments. The parabolic equation has been derived for lossless media where the refractive index is very close to unity. To the authors' best knowledge the paraxial version of the wave equation has not yet been derived for propagation in general lossy dielectric media. In this paper, we first derive the general form of the parabolic wave equation for lossy dielectric media where it can be used for modeling the radio wave propagation through walls. The special form of the parabolic equation for modeling wave propagation in free space can be derived from this general form. We then apply PEM to model propagation of radio waves through a row of windows, reinforced concrete walls and typical corridors inside buildings. As windows are one of the most prevailing architectural elements in buildings, the phenomenon of plane wave transmission through them is of interest. In this paper PEM is used to model the radio wave propagation through windows. The numerical simulation results are presented for both normal and oblique incidence and compared with some reported results. The transmission and reflection characteristics of inhomogeneous walls have been studied by many numerical and analytical methods such as the finite-element method (FEM) and FDTD. In this paper, we use PEM to characterize reflection and transmission properties of reinforced concrete walls under plane wave incidence. The effect of several parameters namely wall thickness, bar diameter and spacing on the transmission coefficients of reinforced concrete walls will be analyzed. Corridors are also popular elements of buildings, so that the analysis of radio wave propagation in corridors has involved many researchers. The PEM is an effective method for modeling wave propagation in these environments. The effect of obstacles such as cupboards and cabinets inside a corridor can be modeled by PEM. This method is also able to model the effects of variations of the corridor direction on the wave propagation. The numerical simulation results will be presented and compared with the available data in the literature.
Ali Reza Soroush; Mohammad Reza Amin naseri
Komeyl Keyhani; Ali Asghar Hamidi
Masoud Tabesh; Siamak Gousheh; Mohammad Javad Yazdan Panah
Abstract
Short-term water demand modeling plays a key role in urban water resources planning and management. The importance of demand prediction is even greater in countries like Iran with frequent periods of drought. Short-term water demand estimation is useful for planning and management of water and wastewater ...
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Short-term water demand modeling plays a key role in urban water resources planning and management. The importance of demand prediction is even greater in countries like Iran with frequent periods of drought. Short-term water demand estimation is useful for planning and management of water and wastewater facilities such as pump scheduling, control of reservoirs and tanks volume, pressure management and water conservation programs. This helps the network managers to decrease vulnerability of the system and consumers and to increase network reliability.
Exact prediction of short-term water demand which is a function of different complex parameters is difficult, time consuming and even impossible. In this research Artificial Neural Networks method (ANN) with back propagation algorithm is used to develop a model for daily water demand prediction of the city of Tehran (center of Iran) using climate parameters and previous daily water consumption records. Several structures were considered with one and two hidden layers and 0- 50 neurons. Also different linear and nonlinear functions were tested for the layers and finally nonlinear function was chosen for the hidden layers and linear function for the output layer. Furthermore, each year was divided into two parts and different models were constructed for hot and cold months.
About four years data for Tehran daily water consumption was available. The model was calibrated by daily data for two years period. At the learning stage, in order to establish the optimal structure of the ANN model, the case of two hidden layers and seven neurons produced the best results and therefore, it was applied for water demand prediction in this city. Results indicate that ANN models can be used to predict Tehran short-term daily water demand, properly. Model evaluation showed that the correlation coefficients for demand prediction are more than 80% for both learning and testing data and the average of error is only 2%. Comparison of the results from ANN and Fuzzy models showed that the ANN outputs are more accurate. Furthermore, a simple formula was proposed to evaluate daily water demand of Tehran using results of a one layer one neuron ANN model with just two input parameters of the last day temperature and water consumption. The results showed good correlation with the measured values with mean error of less than 3%. It can be concluded that a useful model and a simple formula have been produced as the outcomes of this research which can help Tehran water company decision makers for better operating of the system.
Mohammad Kazem Besharati Givi; Akbar Afaghi Khatibi; Mansour Akbari
Abstract
Evidence from the early and late industrializes shows that technology, as the commercial application of scientific knowledge, has been a major driver of industrial and economic development. International technology transfer is now being recognized as having played an important role in the development ...
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Evidence from the early and late industrializes shows that technology, as the commercial application of scientific knowledge, has been a major driver of industrial and economic development. International technology transfer is now being recognized as having played an important role in the development of the most successful late industrializes of the second half of the 20th Century. Our society stands to be significantly influenced by carbon nanotubes, shaped by nanotube applications in every aspect, just as silicon-based technology still shapes society today. Nanotubes can be formed in various structures using several different processing methods. In this paper, the synthesis methods used to produce nanotubes in industrial or laboratory scales are discussed and a comparison is made. A technical feasibility study is conducted by using the multi criteria decision-making model, namely Analytic Hierarchy Process (AHP). The article ends with a discussion of selecting the best method of Technology Transferring of Carbon Nanotubes to Iran.
Amin Ghodousian; Reza Zarghani
Abstract
In this paper, optimization of a linear objective function with fuzzy relational inequality constraints is investigated where the feasible region is formed as the intersection of two inequality fuzzy systems and Yager family of t-norms is considered as fuzzy composition. Yager family of t-norms is a ...
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In this paper, optimization of a linear objective function with fuzzy relational inequality constraints is investigated where the feasible region is formed as the intersection of two inequality fuzzy systems and Yager family of t-norms is considered as fuzzy composition. Yager family of t-norms is a parametric family of continuous nilpotent t-norms which is also one of the most frequently applied one. This family of t-norms is strictly increasing in its parameter and covers the whole spectrum of t-norms when the parameter is changed from zero to infinity. The resolution of the feasible region of the problem is firstly investigated when it is defined with max-Yager composition. Based on some theoretical results, conditions are derived for determining the feasibility. Moreover, in order to simplify the problem, some procedures are presented. It is shown that a lower bound is always attainable for the optimal objective value. Also, it is proved that the optimal solution of the problem is always resulted from the unique maximum solution and a minimal solution of the feasible region. A method is proposed to generate random feasible max-Yager fuzzy relational inequalities and an algorithm is presented to solve the problem. Finally, an example is described to illustrate these algorithms
Alex F. Collins; Alexander W. N. Riasanovsky; John C. Wallace; Stanis law P. Radziszowski
Abstract
The Zarankiewicz number z(b; s) is the maximum size of a subgraph of Kb,b which does not contain Ks,s as a subgraph. The two-color bipartite Ramsey number b(s, t) is the smallest integer b such that any coloring of the edges of Kb,b with two colors contains a Ks,s in the rst color or ...
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The Zarankiewicz number z(b; s) is the maximum size of a subgraph of Kb,b which does not contain Ks,s as a subgraph. The two-color bipartite Ramsey number b(s, t) is the smallest integer b such that any coloring of the edges of Kb,b with two colors contains a Ks,s in the rst color or a Kt,t in the second color.In this work, we design and exploit a computational method for bounding and computing Zarankiewicz numbers. Using it, we obtain several new values and bounds on z(b; s) for 3≤s≤6. Our approach and new knowledge about z(b; s) permit us to improve some of the results on bipartite Ramsey numbers obtained by
Amin Ghodousian; A. Ahmadi; A. Dehghani
Abstract
Sugeno-Weber family of t-norms and t-conorms is one of the most applied one in various fuzzy modelling problems. This family of t-norms and t-conorms was suggested by Weber for modeling intersection and union of fuzzy sets. Also, the t-conorms were suggested as addition rules by Sugeno for so-called ...
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Sugeno-Weber family of t-norms and t-conorms is one of the most applied one in various fuzzy modelling problems. This family of t-norms and t-conorms was suggested by Weber for modeling intersection and union of fuzzy sets. Also, the t-conorms were suggested as addition rules by Sugeno for so-called $\lambda$–fuzzy measures. In this paper, we study a nonlinear optimization problem where the feasible region is formed as a system of fuzzy relational equations (FRE) defined by the Sugeno-Weber t-norm. We firstly investigate the resolution of the feasible region when it is defined with max-Sugeno-Weber composition and present some necessary and sufficient conditions for determining the feasibility of the problem. Also, two procedures are presented for simplifying the problem. Since the feasible solutions set of FREs
Mehran Kadkhodayan; Javad Mosayyebi
Abstract
This paper investigates the forming of sheet metal forming under cycling loading by considering the Bauschinger effect. Different proposed plasticity models which can handle this kind of deformation process have been reviewed in details. For instance, isotropic, kinematic and combined forms in the linear ...
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This paper investigates the forming of sheet metal forming under cycling loading by considering the Bauschinger effect. Different proposed plasticity models which can handle this kind of deformation process have been reviewed in details. For instance, isotropic, kinematic and combined forms in the linear and non-linear cases including the well-known Yoshida and Chaboche's models have been studied. The ability of the best proposed model has been examined in the forming of reverse cup drawing and the obtained results have been compared with some other experimental results. The normalized axial stress, von-mises stress and the punch forces for both first and second stages have been calculated for different materials and thicknesses.
Ali Reza Ashrafi; Ali Ghalavand
Abstract
\vspace{0.2cm}Suppose $G$ is a simple and connected graph. The first and second Zagreb indices of $G$ are two degree-based graph invariants defined as $M_1(G) = \sum_{v \in V(G)}deg(v)^2$ and $M_2(G) = \sum_{e=uv \in E(G)}deg(u)deg(v)$, respectively. The graph $G$ is called $p-$quasi $k-$cyclic, if there ...
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\vspace{0.2cm}Suppose $G$ is a simple and connected graph. The first and second Zagreb indices of $G$ are two degree-based graph invariants defined as $M_1(G) = \sum_{v \in V(G)}deg(v)^2$ and $M_2(G) = \sum_{e=uv \in E(G)}deg(u)deg(v)$, respectively. The graph $G$ is called $p-$quasi $k-$cyclic, if there exists a subset $S$ of vertices such that $|S| = p$, $G \setminus S$ is $k-$cyclic and there is no a subset $S^\prime$ of $V(G)$ such that $|S^\prime| < |S|$ and $G \setminus S^\prime$ is $k-$cyclic. The aim of this paper is to characterize all graphs with maximum values of Zagreb indices among all $p-$quasi $k-$cyclic graphs with $k \leq 3$. & & \vspace{0.2cm}
Gholamreza Hesamian; Mohammad Ghasem Akbari
Abstract
Here are many situations in real applications of decision making where we deal with uncertain conditions. Due to the different sources of uncertainty, since its original definition of fuzzy sets in 1965 \cite{zadeh1965}, different generalizations and extensions of fuzzy sets have been ...
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Here are many situations in real applications of decision making where we deal with uncertain conditions. Due to the different sources of uncertainty, since its original definition of fuzzy sets in 1965 \cite{zadeh1965}, different generalizations and extensions of fuzzy sets have been introduced: Type-2 fuzzy sets \cite{6,13}, Intuitionistic fuzzy sets \cite{1}, fuzzy multi-sets \cite{37} and etc. However, in such cases, it is suitable for experts to provide their preferences or assessments by using linguistic information rather than quantitative values.
Maryam Babaei Zarch; Seyed Abolfazl Shahzadeh Fazeli; Seyed Mehdi Karbassi
Abstract
In this paper, we consider an inverse eigenvalue problem (IEP) for constructing a special kind of acyclic matrices. The problem involves the reconstruction of matrices whose graph is a banana tree. This is performed by using the minimal and maximal eigenvalues of all ...
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In this paper, we consider an inverse eigenvalue problem (IEP) for constructing a special kind of acyclic matrices. The problem involves the reconstruction of matrices whose graph is a banana tree. This is performed by using the minimal and maximal eigenvalues of all leading principal submatrices of the required matrix. The necessary and sufficient conditionsfor the solvability of the problem is derived. An algorithm to construct the solution is provided.
Sima Ranjbarfard; Amin Ghodousian; D. Moazzami
Abstract
In this paper, we present a binary-linear optimization model to prevent the spread of an infectious disease in a community. The model is based on the remotion of some connections in a contact network in order to separate infected nodes from the others. By using this model we nd an exact optimal solution ...
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In this paper, we present a binary-linear optimization model to prevent the spread of an infectious disease in a community. The model is based on the remotion of some connections in a contact network in order to separate infected nodes from the others. By using this model we nd an exact optimal solution and determine not only the minimum number of deleted links but also their exact positions. The formulation of the model is insensitive to the number of edges in a graph and can be used (with complete or local information) to measure the resistance of a network before and after an infectious spreads. Also, we propose some related models as generalizations: quarantining problem including resource constraints (time, budget, etc.), maximum rescued nodes-minimum deleted links problem and minimum removed links problem nding a prespeci ed number of nodes with weakest connections.
