Sharif Digital Repository

This paper addresses the problem of optimal state-feedback design for a class of non-linear systems. The method is applicable to all non-linear systems which can be linearised using the method of state-feedback linearisation. The alternative is to use linear optimisation techniques for the linearised equations, but then there is no guarantee that the original non-linear system behaves optimally. The authors use feedback linearisation technique to linearise the system and then design a state feedback for the feedback-linearised system in such a way that it ensures optimal performance of the original non-linear system. The method cannot ensure global optimality of the solution but the global... 

The problem of designing UWB pulses which meet specific spectrum requirements is usually treated by filtering common pulses such as Gaussian doublets, modified Hermite polynomials and wavelets. When there is the need to have a number of orthogonal pulses (e.g., in a multiuser scenario), a naive approach is to filter all the members of an orthogonal set, which is likely to destroy their orthogonality property. In this paper, we study the design of a set of pulses that simultaneously satisfy the orthogonality property and spectrum requirements. Our design is based on the eigenfunctions of Sturm–Liouville boundary value problems. Indeed, we introduce Sturm–Liouville differential equations for... 

In this article, we investigate the problem of practical output regulation, i.e., to design a controller that brings the system output in the vicinity of a desired target value while keeping the other variables bounded. We consider uncertain systems that are possibly nonlinear and the uncertainty of their linear parts is modeled element wise through a parametric family of matrix boxes. An optimization-based design procedure is proposed that delivers a continuous-time control and estimates the maximal regulation error. We also analyze an event-triggered emulation of this controller, which can be implemented on a digital platform, along with an explicit estimate of the regulation error. ©... 

The harmony search algorithm is one of the latest meta-heuristic algorithms. It benefits from a number of distinguishing features such as a simple concept, few parameters and easy implementation. Combination of web services for inter-enterprise interactions and creation of a composite service which meets users requirements are novel subjects for researches on service oriented systems and process of selecting the best quality based combination is a debatable challenge at this field. In this study an efficient service selection mechanism based on the social harmony search algorithm is proposed to help clients select services with considering the quality attributes. In order to demonstrate the... 

Palladium nanoparticles immobilized on a cross-linked imidazolium-containing polymer were evaluated as a catalyst for Suzuki carbon-carbon cross-coupling reactions using water as the solvent. The nanocatalysts show good catalytic activities for aryl iodides and aryl bromides and moderate activity with aryl chloride substrates. Coupling of sterically hindered substrates could also be achieved in reasonable yields. The heterogeneous catalyst is stable, can be stored without precautions to exclude air or moisture, and can be easily recycled and reused  

Objective(s): Multiple sclerosis (MS) is considered as a chronic type of an inflammatory disease characterized by loss of myelin of CNS. Recent evidence indicates that Interleukin 17 (IL-17)-producing T helper cells (Th17 cells) population are increased and regulatory T cells (Treg cells) are decreased in MS. Despite extensive research in understanding the mechanism of Th17 and Treg differentiation, the role of microRNAs in MS is not completely understood. Thereby, as a step closer, we analyzed the expression profile of miR-9-5p and miR-106a-5p, and protein level of retinoic acid receptor (RAR)-related orphan receptor C (RORC; Th17 master transcription factor) as direct target of miR-106a-5p... 

Assessment of respiratory volume is extensively performed in clinical applications in order to assess the cases of respiratory illness and the progression of the respiratory syndromes. Respiratory plethysmography is employed to determine the changes of chest volume to monitor breathing. A wearable respiration measuring system has been introduced to detect volume variations of chests. The system consists of a flexible sensor, stretchable cloth and electrical board. The flexible sensor, which measures electrical voltage produced by extension movements, is installed inside the shirt and nearly contacts the chest. The system can be used everywhere and be self-applied by patients. The main... 

This paper proposes a method to suboptimally tune the control parameters in a conventional Lyapunov-Based method which shares the same concept of control design with sliding mode approach as applied to the robot manipulators. Optimal tuning of such parameters involves handling of nonlinearities in system dynamics and cost functions, which makes the problem challenging. We propose a step-by-step numerical algorithm that select suboptimal parameters while ensuring system stability. The controller is, suboptimal due to the facts that (1) it is in the form of a Slotine-type sliding mode control, (2) the numerical recursive algorithm might fall into a local minimum, and (3) the controller... 

Transparent electrowetting is a branch of Electrowetting on Dielectric (EWOD) devices that use transparent electrodes. These devices are often utilized for optical applications like liquid lenses and reflective displays. In this paper, for the first time, a transparent EWOD with permanent liquid electrodes is introduced. A conductive solution was used as electrodes instead of conventional solid-state ones. We study the speed of droplets in both the proposed design and a similar conventional Printed Circuit Board (PCB) EWOD. The concept of Liquid Electrode EWOD (LEWOD) is successfully implemented on both rigid and flexible substrates. Our results generally show a promising performance similar... 

There are several key challenges in performing cache-based attacks on ARM-based devices. Lipp et al. introduced various techniques to tackle these challenges and applied successfully different cache-based attacks on ARM-based mobile devices. In the cache-based attacks proposed by Lipp et al. it is assumed that the attacker has access to the mapping of virtual addresses to physical addresses through/proc/self/pagemap which is an important limiting factor in Linux and newer versions of Android operating systems. To access this mapping, the attacker must know the root of the operating system. In this paper, we introduce an Evict+Reload attack on the T-table-based implementation of AES which... 

CPU caches are powerful sources of information leakage. To develop practical cache-based attacks, the need for automation of the process of finding exploitable cachebased side-channels in computer systems is felt more than ever. Cache template attack is a generic technique that utilizes Flush+Reload attack in order to automatically exploit cache vulnerability of Intel platforms. Cache template attack on the T-table-based AES implementation consists of two phases including the profiling phase and key exploitation phase. Profiling is a preprocessing phase to monitor dependencies between the secret key and behavior of the cache memory. In addition, the addresses of T-tables can be obtained... 

In the present study, two novel annular photobioreactors (PBR) were developed to enhance microalgae growth. One of these photobioreactors used mirrors outside the PBR, while the other one utilized phosphorescence materials inside the PBR. The results of the study suggested that the use of mirrors and phosphorescence materials led to 70% and 30% increase, respectively, in the light intensity without any additional energy consumption. Further, the results revealed that when compared with the base case, the biomass concentration increased by 91% and 24% in PBR with mirrors and phosphorescence materials, respectively. In conclusion, an improvement in PBRs resulted in efficient light to biomass... 

The low erosion resistance of titanium and its alloys has prevented their widespread application as joint implants. In addition, one essential requirement for the implants to bond with the living bone is the formation of a bone-like apatite on their surfaces in the host body. To enhance the erosion resistance of the surface, a diffused layer of TiB2 was formed at 1000uC on the commercial pure titanium. Hydroxyapatite was then coated on the boronised titanium by means of dip coating in a sol-gel solution. In order to confirm the biocompatibility of the specimens, they were soaked in a simulated body fluid for several days. The surface morphology of the specimens after exposure was studied by... 

Following Gorokhovsky and Lott and using an extension of the b-pseudodifferential calculus of Melrose, we give a formula for the Chern character of the Dirac index class of a longitudinal Dirac type operators on a foliated manifold with boundary. For this purpose we use the Bismut local index formula in the context of noncommutative geometry. This paper uses heavily the methods and technical results developed by E. Leichtnam and P. Piazza  

In this short note we apply methods introduced by B. Hanke and T. Schick to prove the vanishing of (low degree) higher Â-genera for spin manifolds admitting a positive scalar curvature metric. Our aim is to provide a short proof for this beautiful result  

We proposed a Primal-Dual Interior Point Method (PDIPM) to solve a combined Environmental and Economic Power Dispatch (EEPD) problem. The EEPD problem is a multiobjective problem with competing and non-commensurable objectives. The PDIPM produces a set of nondominated Pareto optimal solutions for the problem. Fuzzy set theory is employed to extract a compromise nondominated solution. The proposed algorithm is applied to the standard IEEE 30 bus six-generator test system. Comparison of our PDIPM results with the various algorithms reported in the literature shows that the solutions of the proposed algorithm are very accurate for the EEPD problem  

As the ordinary least squares (OLS) method is very sensitive to outliers as well as to correlated responses, a robust coefficient estimation method is proposed in this paper for multi-response surfaces in multistage processes based on M-estimators. In this approach, experimental designs are used in which the intermediate response variables may act as covariates in the next stages. The performances of both the ordinary multivariate OLS and the proposed robust multi-response surface approach are analyzed and compared through extensive simulation experiments. Sum of the squared errors in estimating the regression coefficients reveals the efficiency of the proposed robust approach. © 2018 Taylor... 

As the ordinary least squares (OLS) method is very sensitive to outliers as well as to correlated responses, a robust coefficient estimation method is proposed in this paper for multi-response surfaces in multistage processes based on M-estimators. In this approach, experimental designs are used in which the intermediate response variables may act as covariates in the next stages. The performances of both the ordinary multivariate OLS and the proposed robust multi-response surface approach are analyzed and compared through extensive simulation experiments. Sum of the squared errors in estimating the regression coefficients reveals the efficiency of the proposed robust approach. © 2017 Taylor... 

Nowadays, many manufacturing and service systems provide products and services to their customers in several consecutive stages of operations, in each of which one or more quality characteristics of interest are monitored. In these environments, the final quality in the last stage not only depends on the quality of the task performed in that stage but also is dependent on the quality of the products and services in intermediate stages as well as the design parameters in each stage. In this paper, a novel methodology based on the posterior preference approach is proposed to robustly optimize these multistage processes. In this methodology, a multi-response surface optimization problem is...