Sharif Digital Repository

Because reversible fans must be able to provide similar performance in either rotation direction, they need to have completely symmetrical blades. In the present study, an elliptic profile with itsmaximum thickness of 8%chord length at themiddle of the chord line is studied. For verification, theNACA0012 airfoilwas once analyzed two-dimensionally in the isolatedformationandonce in cascade formation with0.55 and 0.83 solidities, andthe obtainedresultswere comparedwith numerical and experimental results. Three well-known Reynolds-averaged Navier-Stokes turbulence models including Spalart-Allmaras, realizable κ-ϵ, and shear-stress transport κ-ω were used to find the suitable turbulence method.... 

Because reversible fans must be able to provide similar performance in either rotation direction, they need to have completely symmetrical blades. In the present study, an elliptic profile with itsmaximum thickness of 8%chord length at themiddle of the chord line is studied. For verification, theNACA0012 airfoilwas once analyzed two-dimensionally in the isolatedformationandonce in cascade formation with0.55 and 0.83 solidities, andthe obtainedresultswere comparedwith numerical and experimental results. Three well-known Reynolds-averaged Navier-Stokes turbulence models including Spalart-Allmaras, realizable κ-ϵ, and shear-stress transport κ-ω were used to find the suitable turbulence method.... 

Radio Frequency Identification (RFID) is an easy to use technology for quick and low-cost identification and authentication. Since RFID systems have found in various parts of our daily lives, security awareness about these systems has become one of the prominent topics for researchers. In this study, we investigate two RFID security schemes which both are under Electronic Product Code (EPC) standard. It is shown that both the analyzed protocols have some drawbacks and are vulnerable to several security attacks including secret parameters reveal, impersonation, reader forward secrecy and also one of them does not provide date integrity. In addition, in order to overcome all the discovered... 

Recently, different RFID authentication protocols conforming to EPC Class 1 Generation 2 (EPC C1 G2) standard have been proposed. In 2013, Xiao et al. have proposed an improved mutual authentication protocol which claimed to eliminate the weaknesses of Yoon's protocol that has been proposed in 2012. In this paper, we study the security and the privacy of Xiao et al.'s protocol. It is shown that their protocol suffers from secret parameters reveal, tag impersonation attack, backward and forward traceability attacks. Then, in order to enhance the security and the privacy of this protocol, a modified version is proposed. In order to evaluate our proposed protocol, its security and privacy are... 

Reversible axial flow fans, used in tunnel ventilation systems are designed in a way that as the direction of impeller rotation changes, suction and discharge directions change without any sensible change in flow rate and pressure. Also, their reversibility must be higher than 90%. Therefore, the blade profiles of these fans (S-shaped or elliptic) are designed symmetrically. In the current work, a reversible axial flow fan was studied experimentally and numerically in various ambient conditions and blade positions. Additionally, the experimental test of the fan was performed according to the AMCA-210 standard. Comparison of simulation and experimental results indicated the acceptable... 

Radio frequency identification (RFID) technology is a prominent technology which has been used in most authentication and identification applications. Above all, recently RFID systems have got more attention as an interesting candidate to implement in the internet of things systems. Although RFID systems provide useful and interest services to users, they can also threat the security and the privacy of the end-users. In order to provide the security and the privacy of RFID users, different authentication protocols have been proposed. In this study, we analyze the privacy of three RFID authentication protocols that proposed recently. For our privacy analysis, we use a formal RFID privacy... 

In the last decade, various types of RFID security schemes have been proposed which have tried to provide all security and privacy requirements of end-users. In this paper, we cryptanalyze two new-found key exchange and key agreement security schemes which are proposed by Zhang et al. and Kim in 2012 and 2013 respectively. We present the reveal secret parameter, tag impersonation and traceability attacks on Zhang et al's protocol with success probability '1', and also we show that an attacker can impersonate the tag and the reader of Kim's protocol both with success probabilities '1/4'. We also present some modifications on the structure of studied schemes and propose two modified schemes... 

The governor of hydro power plants should track frequency variations and at the same time provide good response to load disturbances. These two functions are contradictory and the system model changes with the operating point. This paper presents a robust fuzzy logic adaptive load-frequency controller for hydro power plants. The case study is Abbaspour power plant in Iran. © 2007 SICE  

Recently, Radio Frequency Identification (RFID) and Near Field Communication systems are found in various user-friendly services that all of us deal with in our daily lives. As these systems are ubiquitously deployed in different authentication and identification applications, inferring information about our behavior will be possible by monitoring our use of them. In order to provide privacy and security requirements of RFID users in novel authentication applications, lots of security schemes have been proposed which have tried to provide secure and untraceable communication for end-users. In this paper, we investigate the privacy of three RFID security schemes which have been proposed... 

The trade-off between the fuel consumption and drag coefficient makes the investigations of drag reduction of utmost importance. In this paper, the rear-end shape optimization of Ahmed body is performed. Before changing the geometry, to identify the suitable simulation method and validate it, the standard Ahmed body is simulated using k − ω shear stress transport (SST) and k-epsilon turbulence models. The slant angle, rear box angle, and rear box length as variables were optimized simultaneously. Optimizations conducted by genetic algorithm (GA) and particle swarm optimization (PSO) methods indicate a 26.3% decrease in the drag coefficient. To ensure the validity of the results, a... 

Load-frequency control is the intrinsic function of the governor in the power plants. It would be used in variant structures depend on the controller type such as PID, adaptive, fuzzy or robust. Temporary droop structure governor (TDSG) was commonly used in Hydro power plants (HPP). After representation of TDSG, this paper is dedicated to introducing a procedure for tuning TDSG parameters. The technique is based on pole placement for the closed loop poles of the system. These poles correspond to the TDSG parameters that by accurate tuning of them, pole placement is accomplished. The results for tuning TDSG of Abbaspour HPP have been presented as well. © 2008 IEEE  

The trade-off between the fuel consumption and drag coefficient makes the investigations of drag reduction of utmost importance. In this paper, the rear-end shape optimization of Ahmed body is performed. Before changing the geometry, to identify the suitable simulation method and validate it, the standard Ahmed body is simulated using k − ω shear stress transport (SST) and k-epsilon turbulence models. The slant angle, rear box angle, and rear box length as variables were optimized simultaneously. Optimizations conducted by genetic algorithm (GA) and particle swarm optimization (PSO) methods indicate a 26.3% decrease in the drag coefficient. To ensure the validity of the results, a... 

The trade-off between the fuel consumption and drag coefficient makes the investigations of drag reduction of utmost importance. In this paper, the rear-end shape optimization of Ahmed body is performed. Before changing the geometry, to identify the suitable simulation method and validate it, the standard Ahmed body is simulated using k − ω shear stress transport (SST) and k-epsilon turbulence models. The slant angle, rear box angle, and rear box length as variables were optimized simultaneously. Optimizations conducted by genetic algorithm (GA) and particle swarm optimization (PSO) methods indicate a 26.3% decrease in the drag coefficient. To ensure the validity of the results, a... 

A graph G is called uniquelyk-list colorable (UkLC) if there exists a list of colors on its vertices, say L= { Sv∣ v∈ V(G) } , each of size k, such that there is a unique proper list coloring of G from this list of colors. A graph G is said to have propertyM(k) if it is not uniquely k-list colorable. Mahmoodian and Mahdian (Ars Comb 51:295–305, 1999) characterized all graphs with property M(2). For k≥ 3 property M(k) has been studied only for multipartite graphs. Here we find bounds on M(k) for graphs embedded on surfaces, and obtain new results on planar graphs. We begin a general study of bounds on M(k) for regular graphs, as well as for graphs with varying list sizes. © 2018, Springer... 

The increased number of female smokers is considered a global health challenge in recent years. One of the detrimental effects of smoking is sexual hormone fluctuation causing female sexual dysfunction (FSD). This systematic review and meta-analysis aimed to investigate the effects of smoking leading to FSD. Electronic databases (PubMed, Scopus, Web of Science, Embase, Science Direct, and Google Scholar) were hired for systematic searching. Until June 2022, whole qualified studies reporting the consequences of smoking on FSD were gathered for data analysis based on the random effects model (CMA software, v.2). Study heterogeneity and publication bias were also assessed using I2 index and...