Sharif Digital Repository

Increasing competition in the transport commercial market has resulted in many changes in the aircraft design process. There is a great tendency to include economic factors such as "affordability" In the design process. On the other hand, the so-called market dynamics are also getting complicated and a design team has to deal with many uncertainties as far as the business environment is concerned. This leads to the need for new decision-making tools in the early stages of the design process. This paper introduces a decision-making algorithm based on fuzzy logic systems which provides a structured approach to deal with uncertainties in the aircraft preliminary design. The developed tool leads... 

Design of robotic fish based on hydrodynamics is presented and Lighthill's Large Amplitude Elongated Body Theory (LAEBT) is used for modeling of the robotic fish in linear path. A PID controller for control of speed in linear path is designed and simulations are presented which shows its effectiveness for speed control of the robotic fish. It has been shown that in perspective of used approximate LAEBT model, the used control law maintains kinematic parameters and therefore, the associated efficiency will be maintained  

This paper addresses the issues of energy efficiency in robotic fish design by use of hydrodynamic models. The use of LighthilPs small-amplitude elongated body theory for designing of robotic fish, obtaining optimal kinematics and dynamic analysis with emphasis on compliant mechanism is presented. Simulation results for a sample case have demonstrated the importance of proposed approach in robotic fish design. Copyright © 2008 by ASME  

Here, we develop two quantum-computational schemes for supervised and unsupervised classification tasks in a quantum world by employing the quantum information-geometric tools of quantum fidelity and quantum search algorithm. Presuming that pure states of a set of given quantum systems (or objects) belong to one of two known classes, the objective here is to decide to which of these classes each system belongs—without knowing its state. The supervised binary classification algorithm is based on having a training sample of quantum systems whose class memberships are already known. The unsupervised binary classification algorithm, however, uses a quantum oracle which knows the class membership... 

One of the equivalent formulations of the Kadison–Singer problem which was resolved in 2013 by Marcus, Spielman and Srivastava, is the “paving conjecture”. In this paper, we first extend this result to real stable polynomials. We prove that for every multi-affine real stable polynomial satisfying a simple condition, it is possible to partition its set of variables to a small number of subsets such that the “restriction” of the polynomial to each subset has small roots. Then, we derive a probabilistic interpretation of this result. We show that there exists a partition of the underlying space of every strongly Rayleigh process into a small number of sets such that the restriction of the point... 

Abstract: In this research, photocatalytic conversion of CO2 to methanol was investigated under ultraviolet (UV-A) light. For this purpose, a number of the metal–organic framework photocatalysts, including MIL-101(Fe), graphene oxide (GO), GO–iron oxide (Fe3O4), MIL-101(Fe)–GO–Fe3O4 5, 10, and 20% were synthesized and characterized by X-ray powder diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy (RAMAN), scanning electron microscope (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy/map (EDS/map), Brunauer–Emmett–Teller (BET) surface area analysis and Barrett–Joyner–Halenda (BJH), UV–Vis diffuse reflectance spectroscopy... 

A novel method for direction-of-arrival (DOA) estimation is proposed. This technique employs the excellent performance of Bartlett method in coherent environments as well as high resolution and low computational complexity of Beamspace MUSIC. Simulation results show that the use of Beamspace MUSIC with Bartlett yields significantly improved performance compared to the original MUSIC especially in highly correlated situations. © 2008, Electromagnetics Academy. All rights reserved  

Bashagard district is one of the important malaria endemic areas in southern Iran. From this region a total of 16,199 indigenous cases have been reported in recent years. The aim of this study was to determine the situation of the disease and provide the risk map for the area. ArcGIS9.2 was used for mapping spatial distribution of malaria incidence. Hot spots were obtained using evidence-based weighting method for transmission risk. Environmental factors including temperature, relative humidity, altitude, slope and distance to rivers were combined by weighted multi criteria evaluation for mapping malaria hazard area at the district level. Similarly, risk map was developed by overlaying... 

In this paper, we propose a data offloading algorithm in a network comprised of a macro base station and a few number of WiFi access points with overlapped coverage areas. The main goal of our algorithm is how to assign offloaded mobile stations (MSs) to access points (APs). Our approach in proposing the algorithm is based on mapping the problem onto finding a suitable matching algorithm, in order to minimize the average delay of the offloaded packets as one of the main QoS parameters on the one hand and to maximize the utility of the APs on the other hand. The utility of each AP is considered to be a combination of monetary benefit due to offloading service and the cost due to extra energy... 

Because of fluctuation in leg tension, pitch motion is very effective in fatigue and life safety of leg elements in tension leg structures (TLSs). In this paper exact solution for pitch vibration of a TLS interacting with ocean wave is presented. The legs are considered as elastic springs. The flow is assumed to be irrotational and single-valued velocity potentials are defined. The effects of radiation and scattering are considered in the boundary value problem. Because of linear behavior of legs during wave excitation, ignoring coupling effects with other degrees of freedom, the analytical solution of pitch response has good agreement with the real behavior of the structure  

The main purpose of this study is to offer a new method for transient analysis of availability and survivability of a system with the identical components and one repairman and with every combination of components either standard system for example series systems, parallel systems, stand-by systems and K out of N systems or complex system. This method is a technique for fault tree evaluation too. The considered system is supposed to consist of n components and there are some composition of them that systems the failure occurs when one of its composition occur. Some concepts such as fault tree, Markov models, Eigen vectors and Eigen values are employed for analyzing the transient availability... 

We propose a general mobility model based on region splitting and mapping each subregion on a multi-server node. By using the theory of multi-class Jackson queueing network with multiserver nodes and employing the product-form solution for such queueing networks, we obtain an analytical form for the spatial traffic distribution in a typical region with specific number of users. To this end, we consider the spatial statistical pattern for new and handoff call arrivals and the ratio between these two types of arrivals. At last, we apply our new model to some simple mobility scenarios and compute the resultant active user's location densities. © 2003 IEEE  

In this paper, we focus on the reverse link traffic analysis of a code-division multiple-access (CDMA) cellular network in dynamic environments. In this respect, we propose a new and flexible traffic model, which takes into account the interference-limitedness attribute of CDMA capacity as well as its soft-handoff feature. This new traffic model is developed according to interference-based call admission control (ICAC) method and a geographical structure with three regions. The main advantage of this traffic model is in its flexibility when we consider different traffic conditions including time-varying status of traffic in the neighboring cells  

In this paper, two basic new call admission control policies in soft-handoff regions in Code-Division Multiple-Access (CDMA) cellular networks are compared. The two policies are Independent Decision Policy (IDP), which is, approximately, equivalent to a directed retry policy proposed for non-CDMA cellular networks and Collective Decision Policy (CDP). The merits in this comparison include the tradeoff between carried traffic and quality loss probability while maintaining other traffic parameters (such as blocking and dropping (handoff failure) probabilities) sufficiently low. Using numerical results, it is deduced that the CDP leads to a better overall performance. Another important issue... 

Central composite orthogonal design was applied to quantify relations of xylanase production, loss of dry matter and change of pH with four critical variables during solid state fermentation of a mixture of wheat bran and wheat straw on which Aspergillus niger CCUG 33991 was cultivated. The studied variables included the percentage of wheat straw, wheat bran, temperature, moisture content, and fermentation time. The second-order quadratic model predicted the xylanase activity at a suitable set of conditions namely 29°C, 55% moisture content, and 50 hours of fermentation to be 1465 U/g of fermented dry matter which differed less than 6% from measured value at this set of conditions.... 

Cultural adaptation and validation of the Persian version of the Arthritis Measurement Scales 2-Short Form (AIMS2-SF). The translation and cultural adaptation of the original questionnaire was carried out in accordance with published guidelines. Three hundred and fifty consecutive Persian-speaking patients with rheumatoid arthritis (RA) were asked to complete the AIMS2-SF, the Short Form Health Survey (SF-36), and four visual analog scales (VAS) for pain, joint stiffness, and patient's and physician's global assessment to test convergent validity. In addition, 90 randomly selected patients were asked to complete the questionnaire 48 h later for the second time. Moderate to high correlation... 

Accurate implementation of river interactions with subsurface water is critical in large-scale hydrologic models with a constant horizontal grid resolution when models apply kinematic wave approximation for both hillslope and river channel flow. The size of rivers can vary greatly in the model domain, and the implemented grid resolution is too coarse to accurately account for river interactions. Consequently, the flow velocity is underestimated when the width of the rivers is much narrower than the selected grid size. This leads to inaccuracy and uncertainties in calculations of water quantities. In addition, the rate of exfiltration and infiltration between the river and the subsurface may... 

In this letter, we consider a cache-enabled cloud radio access network with single-antenna base stations and single-antenna mobile users. Each base station can access the central processor of the network via a separate backhaul link with limited capacity. We utilize the interference alignment scheme as the transmission strategy between base stations and users. By assuming a block transmission scheme, we define a related data transmission delay. We derive the transmission delay and network power consumption. At last, we solve the problem of joint optimization of data transmission delay and network power consumption using DC programming algorithm. In our numerical results, we investigate the...