Sharif Digital Repository

So far, the need for power systems to be control automated has been approached. Moreover, the advent of smart technological infrastructures calls for a more systematic and well-designed schemes for data acquisition process. Hence, Remote Terminal Units (RTUs) are going to be considered as a crucial part of smart grid puzzle in power distribution systems. This paper aims to present a novel practical approach to have the RTU placement dilemma unraveled in power distribution systems. Practically approaching in this paper, some pragmatic factors of major importance in this respect are introduced. A framework with which the utility's experts' knowledge could be efficiently exploited is presented... 

Supervisory control and data acquisition (SCADA) infrastructures have so far been brought into the huge amount of focus since the need for a more reliable power system accosting with the catastrophic events of interruptions has been raised. Hence, benefiting from an automation technology which can remotely monitor and coordinate commands to enable immediate response and switching are obviously inevitable. This paper outlines an implementable method in response to the goal of placement of remote terminal units (RTUs) which are in charge for data acquisition and control in a power distribution system. In this light, a new practical methodology based on the robust decision making (DM) method,... 

An integrated approach is presented for predicting granule particle size using Partial Correlation (PC) analysis and Artificial Neural Networks (ANNs). In this approach, the proposed model is an abstract form from the ANN model, which intends to reduce model complexity via reducing the dimension of the input set and consequently improving the generalization capability of the model. This study involves comparing the capability of the proposed model in predicting granule particle size with those obtained from ANN and Multi Linear Regression models, with respect to some indicators. The numerical results confirm the superiority of the proposed model over the others in the prediction of granule... 

The gelatin/gum arabic microcapsules encapsulating peppermint oil were prepared by complex coacervationusing tannic acid as hardening agent. The effects of various parameters, including concentration of wall material, core material, tannic acid and Tween 80 were investigated on particle size and encapsulation efficiency. For statistical evaluation of the parameters, Taguchi method was concerned. The size of prepared spherical microcapsules was 19-66 micrometers. The results showed that, particle size increased with increasing the core and the wall concentration and decreased with increasing tannic acid and Tween 80 concentraIfd efficiency increased by increasing the core and wall... 

This letter addresses the problem of joint localization and clock synchronization in distributed multiple-input multiple-output (MIMO) radar systems. While the well-known two-stage weighted least squares (WLS) method provides an acceptable estimate of target position when a rough approximation of antennas clock parameters, the drifts and offsets, is available, its performance can degrade quickly if the level of uncertainty in these values increases. The proposed method offers a solution for synchronizing the clocks while simultaneously improving the target position estimate. The uncertainty in positions of antennas is also taken into account. The presented method is shown to be approximately... 

The development of a nonenzymatic glucose sensor working in real human body conditions through a noninvasive sampling approach has attracted considerable attention. Hence, this work focuses on the development of a new nonenzymatic glucose sensor based on flower-like Au nanostructures (F-AuNTs) and graphene oxide (GO) as a supporting matrix. The F-AuNTs-GO hybrid was synthesized by simple drop casting of the GO suspension onto the graphite sheet (GS) followed by electrodeposition of F-AuNTs on GO nanosheets at 3 V in a two-electrode system. The electrocatalytic activity of the F-AuNTs-GO/GS sensor toward glucose electrooxidation was initially evaluated in a 0.1 M buffer phosphate solution (pH... 

Among all proposed structures for optical networks, the optical packet switching (OPS) scheme, due to its practical implementation of IPs in an optical configuration and the consequent advantages, is a prizeworthy candidate for being employed in metropolitan area network and local area network communication levels. One of the few problems frequently met using the OPS structure in the fiber-optics realm is the lack of optical buffers, thus deteriorating the system's flexibility and quality of service. For example, optical label switching networks that have been developed recently based on the generalized multiprotocol label switching protocol, profoundly suffer from this setback which is... 

Purpose: This paper aims to study the lateral behavior of cold-formed steel walls with K-shaped bracing by finite element modeling. Design/methodology/approach: The braces which have the same section as those for studs and tracks are connected to the frame by screw connections. By pushover analysis, lateral performance of two frame categories, with different dimensions and bracing arrangements, is examined, and the force-displacement diagram and the ultimate strength of walls are extracted. Probable failure modes during lateral loading including distortional buckling of studs, buckling in braces and failure of connections are simulated in the numerical model, and some strengthening... 

Among all proposed structures for optical networks, the optical packet switching (OPS) scheme, due to its practical implementation of IPs in an optical configuration and the consequent advantages, is a prizeworthy candidate for being employed in metropolitan area network and local area network communication levels. One of the few problems frequently met using the OPS structure in the fiber-optics realm is the lack of optical buffers, thus deteriorating the system's flexibility and quality of service. For example, optical label switching networks that have been developed recently based on the generalized multiprotocol label switching protocol, profoundly suffer from this setback which is... 

To obtain wider openings than those provided by Chevron bracing, the braces are cranked and connected to the frame corner by an additional brace to form double y-shaped bracings. However, y-bracings are prone to instability and out of plane buckling, accompanied by low hysteretic energy absorption. An experimental research program, focused on y-bracing, was conducted at the BHRC structural engineering laboratory. Specimens presented in this paper include three full-scale single bay frames, with symmetric y-bracing of different cross sections and connection types. In addition, one specimen with Chevron bracing was tested as a reference. A quasi-static cyclic loading was applied increasingly... 

Isolated Word Recognition (IWR) is becoming increasingly attractive due to the improvement of speech recognition techniques. However, the accuracy of IWR suffers when large databases or words with similar pronunciation are used. The criterion for accurate speech recognition is suitable segmentation. However, the traditional method of segmentation equal segmentation does not produce the most accurate result. Furthermore, utilizing manual segmentation based on events is not possible in large databases. In this paper, we introduce an intelligent segmentation based on Hierarchical Temporal Decomposition (HTD). Based on this method, a temporal decomposition (TD) algorithm can be used to... 

Because of the complicated buckling characteristics of Y-shaped bracings, calculation of their strength is beyond routine engineering procedures. A method based on slope-deflection equations incorporating stability functions has been used for computation of buckling eigenvalues and effective length factors. Lateral strength is computed based on the least buckling strength of bracing members. This study is limited to bracings with similar sections and fixed end connections resisting out-of-plane rotation. Lateral strengths predicted by the analytical method for two cases are compared with experimental results on full-scale specimens. It is shown that the proposed analytical method predicts... 

The hydrodistilled oils of the aerial parts of Artemisia armeniaca and Artemisia splendens have been analyzed by a combination of GC and GC/MS. The main components of A. armeniaca were α-pinene (41.9%) and 1,8-cineole (20.6%) followed by spathulenol (6.7%) and limonene (5.6%). l,8-cineole(14.5%), germacrene D (14.3%), α-pinene (11.3%) and bicyclogermacrene (11.3%) were found to be the major constituents of A. splendens  

In this letter, an efficient estimator for 3-D target localization in distributed multiple-input multiple-output (MIMO) radars using time delay (TD) and angle of arrival (AOA) measurements is proposed. First, an approximately equivalent maximum likelihood (ML) estimation problem is formulated. Then, the aforementioned ML problem is recast into a convex optimization problem for which we derive a semi closed-form solution that eventually boils down to finding the roots of certain polynomials. Using numerical simulations, we demonstrate that the proposed estimator reaches the Cramer-Rao lower bound (CRLB) up to relatively high Gaussian measurement noise levels. Furthermore, the proposed method... 

For a given set of n colored points with k colors in the plane, we study the problem of computing the smallest color-spanning axis-parallel square. First, for a dynamic set of colored points on the real line, we propose a dynamic structure with O(log2 n) update time per insertion and deletion for maintaining the smallest color-spanning interval. Next, we use this result to compute the smallest color-spanning square. Although we show there could be Ω(kn) minimal color-spanning squares, our algorithm runs in O(nlog2 n) time and O(n) space  

We study a variant of the problem of spanning colored objects where the goal is to span colored objects with two similar regions. We dedicate our attention in this paper to the case where objects are points lying on the real line and regions are intervals. Precisely, the goal is to compute two intervals together spanning all colors. As the main ingredient of our algorithm, we first introduce a kinetic data structure to keep track of minimal intervals spanning all colors. Then we present a novel algorithm using the proposed KDS to compute a pair of intervals which together span all the colors with the property that the largest one is as small as possible. The algorithm runs in O(n2 log n)... 

Suppose n colored points with k colors in Rd are given. The Smallest Color-Spanning Ball (SCSB) is the smallest ball containing at least one point of each color. As the computation of the SCSB in Lp metric (p≥1) is time-consuming, we focus on approximately computing the SCSB in near-linear time. Initially, we propose a 3-approximation algorithm running in O(n logn) time. This algorithm is then utilized to present a (1+ε)-approximation algorithm with the running time of O((1/ε)dn logn). We improve the running time to O((1/ε)dn) using randomized techniques. Afterward, spanning colors with two balls is studied. For a special case where d=1, there is an algorithm with O(n2) time. We demonstrate... 

In this paper, recovery of penicillin G from mycel-containing fermentation broth through physical extraction is investigated. The values of degree of extraction are evaluated as a function of media pH, partition coefficient between aqueous and organic phases for undissociated acid and the pKa of penicillin. The pH variations were measured during extraction operation and the optimum pH value for penicillin G recovery considering its decomposition was obtained. The mass transfer analysis of the extraction system was carried out using two-resistance mass transfer theory. The overall as well as aqueous and organic phase mass transfer coefficients were determined. The investigated mass transfer... 

Effective diffusion coefficient is an important parameter which needs to be determined in different fields of study, such as cathode catalyst layers of PEM fuel. For this purpose, a Loschmidt diffusion cell can be used. When a porous medium is placed in Loschmidt apparatus, the effective gas diffusion coefficient (EGDC) of this section must be correlated by diffusion coefficient in absence of a porous medium. In the previous researches studying the Loschmidt diffusion cell, a simplifying infinite-length assumption was used in the analytical solution. Therefore, the solution is only applicable for a short time range, and this can result in high error. In order to overcome this challenge, the... 

A lucky labeling of a graph G is a function l:V(G)→N, such that for every two adjacent vertices v and u of G, σ w∼vl(w)≠ σ w∼ul(w) (x∼y means that x is joined to y). A lucky number of G, denoted by η(G), is the minimum number k such that G has a lucky labeling l:V(G)→{1,⋯,k}. We prove that for a given planar 3-colorable graph G determining whether η(G)=2 is NP-complete. Also for every k≥2, it is NP-complete to decide whether η(G)=k for a given graph G