Sharif Digital Repository

Spectral Subtraction (SS), as a speech enhancement technique, originally designed for improving quality of speech signal judged by human listeners. it usually improve the quality and intelligibility of speech signals, while the speech recognition systems need compensation techniques capable of reducing the mismatch between the noisy speech features and the clean models. This paper proposes a novel approach for solving this problem by considering the SS and the speech recognizer as two interconnected components, sharing the common goal of improved speech recognition accuracy. The experimental evaluations on a real recorded database and the TIMIT database show that the proposed method can... 

γ-Alumina is used to catalyze the Cannizzaro reaction in the absence of any base under microwave irradiation in high yields. In the case of terephthalaldehyde the reaction is carried out with high selectivity  

A combination of silica chloride and wet SiO2 was used as an effective deacetalizating agent for the conversion of acetals to their corresponding carbonyl derivatives under mild and heterogeneous condition  

In this paper, system identification techniques are applied to accurately characterize the frequency behavior of a commercially available but with unknown characteristics of a photoplethysmography (under the commercial name of Pulse Sensor). Although claimed to be open-source, the electronic schematic of this device does not allow for a full characterization of it. Therefore a second order auto-regressive with exogenous input model has been employed to find the frequency response of this system. An optical excitation circuit was developed to send a pseudo-random signal to the Pulse Sensor. Results show that the model is able to reproduce the output with a fitness of 89.7 %. The obtained... 

In this study, we discuss the postural stability of a nonprehensile manipulation problem, which deals with multibody objects. As a metric for postural stability, we define PRI. Then, the system is posturally stable, if PRI is inside the convex hull of the object-manipulator contact surface. We then discuss that dynamic biped locomotion is a special case of dynamic nonprehensile manipulation in all aspects; we prove that ZMP (zero-moment point) and FRI (zoot rotation indicator) are special cases of PRI (palm rotation indicator). Simulations and experiments corresponding to simple examples support the results  

Lander-Waterman's coverage bound establishes the total number of reads required to cover the whole genome of size G bases. In fact, their bound is a direct consequence of the well-known solution to the coupon collector's problem which proves that for such genome, the total number of bases to be sequenced should be O(G ln G). Although the result leads to a tight bound, it is based on a tacit assumption that the set of reads are first collected through a sequencing process and then are processed through a computation process, i.e., there are two different machines: one for sequencing and one for processing. In this paper, we present a significant improvement compared to Lander-Waterman's... 

Cardiotocograph (CTG) is widely used in everyday clinical practice for fetal surveillance, where it is used to record fetal heart rate (FHR) and uterine activity (UA). These two biosignals can be used for antepartum and intrapartum fetal monitoring and are, in fact, nonlinear and non-stationary. CTG recordings are often corrupted by artifacts such as missing beats in FHR, high-frequency noise in FHR and UA signals. In this paper, an empirical mode decomposition (EMD) method is applied on CTG signals. A recursive algorithm is first utilized to eliminate missing beats. High-frequency noise is reduced using EMD followed by the partial reconstruction (PAR) method, where the noise order is... 

In this paper, we consider $K$ -user interference channels with $M$ antennas per node and with backhaul collaboration in one side (among the transmitters or among the receivers), for $M,Kin mathbb {N}$ , and investigate the tradeoff between the rate in the channel versus the communication load in the backhaul. In this investigation, each node is equipped with $M$ antennas and we focus on a first order approximation result, where the rate of the wireless channel is measured by the degrees of freedom (DoF) per user, and the load of the backhaul is measured by the entropy of backhaul messages per user normalized by $log $ of transmit power, at high power regimes. This tradeoff is fully... 

This study concentrated on the formulation of self-flowing and an energy efficient lightweight aggregate foamed concrete (LAFC) to be employed as thermal insulation, thermal mass and structural material. Low density concrete mixtures (for the density values from 800 to 1300 kg/m3) were prepared by changing the volume of lightweight expanded clay aggregate (ECA) from 49.4% to 20.1%. Flowing properties of concrete mixtures were improved with the help of stable foam. Ordinary Portland cement (OPC) was replaced by the 5% and 10% silica fume (SF) to examine the influence of SF on the properties of LAFC. Compressive strength and tensile strength of LAFC mixtures were respectively enhanced from 6.5... 

In this paper, we study the problem of delay minimization in NFV-based networks. In such systems, the ultimate goal of any request is to compute a sequence of functions in the network, where each function can be computed at only a specific subset of network nodes. In conventional approaches, for each function, we choose one node from the corresponding subset of the nodes to compute that function. In contrast, in this work, we allow each function to be computed in more than one node, redundantly in parallel, to respond to a given request. We argue that such redundancy in computation not only improves the reliability of the network, but would also, perhaps surprisingly, reduce the overall... 

Multi-site photoplethysmography is an optoelectronic technique that measures changes in blood volume associated with cardiac contraction. Photoplethysmogram (PPG) recording enables researchers to study the vascular and hemodynamic properties of human subjects. Currently, there is no commercial system available in the market to perform multi-channel PPG recording. The measurements can be obtained from fingertips, ear lobes and toes due to their low absorption and high degree of vasculature. The main objective of this project is to develop a suitable data compression algorithm for two-channel simultaneous high resolution wireless PPG recording system. MATLAB software was used during the... 

A new reflectance optical sensor array for locating fetal signal transabdominally has been determined in this study. The selection of optical sensor array is based on the highest Irradiance (μW/m2) value estimated on respected detectors. A three-layer semi-infinite tissue model which consists of maternal, amniotic fluid sac and fetal tissues is employed to study the optical sensor array configuration. By using statistical error approach, the number of rays injected to the system can be set to 1 million rays with ±3.2% of simulation error. The simulation results obtained from Monte Carlo technique reveal that diamond configuration is the most suitable configuration of reflectance optical... 

The development of a synthetic model of a pregnant woman abdomen with amniotic fluid and a fetus is discussed comprehensively in this paper. The model is intended to be used for studying the light propagation through physical 3D model of pregnant woman in reflectance mode. To construct the model, reported dimension values of body curvature in 26 and 28 weeks of pregnant woman are being used as main references. Although slightly adjustments have been made to the body dimensions, the values are still within the range of reference values. Optical simulation has been performed in order to test the model capability. Given the reasonable computational time and encouraging preliminary results, the... 

We consider a cellular wireless system including several interfering multi-user multi-antenna uplink channels, where the base station of each cell has to locally recover the messages of its corresponding users. We use a linear Wyner model, where each base station experiences interference only from the users in the two neighboring cells. Each base station is connected to the two nearby base stations through a backhaul link. The objective is to achieve the maximum degrees of freedom per cell, with minimum aggregated load in the backhaul. We propose a successive cooperative alignment scheme, in which each base station forms backhaul messages by combining the previous received backhaul messages... 

We consider a K-user Interference Channel where each transmitter is interested in conveying a message to its corresponding receiver. In addition, we assume a fully connected noiseless backhaul network through which receivers can collaborate and help each other recover their desired messages. In this paper, we fully characterize the trade-off between the rate in wireless link (per user) in terms of degrees of freedom (DoF) versus backhaul load (per user) for large values of K. In particular, we characterize the optimal trade-off for all values of K, where K is an even number. For odd values of K, we characterize the trade-off within a gap of 2(k - 1)/k(k + 1), which goes to zero as K... 

This research work was conducted to investigate the anatomical and antioxidant studies of some ethnoveterinary grasses (Cenchrus pennisetiformis and Dichanthium annulatum). The anatomical characteristics (compact epidermal layer, large cortical cells, thickened sclerenchyma, central and scattered vascular bundles, large metaxylem, small protoxylem, and centrally located pith) were observed. For the antioxidant activity studies, the crude methanol extract was prepared by maceration techniques and different fractions were prepared (n-hexane, chloroform, and aqueous solution). The maximum antioxidant potential in DPPH was shown by C. pennisetiformis at a concentration of 250 µL in the... 

In this work, we introduce a category of dynamic manipulation processes, namely passive dynamic object manipulation, according to which an object is manipulated passively. Specifically, we study passive dynamic manipulation here. We define the main concept, discuss the challenges, and talk about the future directions. Like other passive robotic systems, there are no actuators in these systems. The object follows a path and travels along it under the effect of its own weight, as well as the interaction force applied by each manipulator on it. We select some simple examples to show the concept. For each example, dynamic equations of motion are derived and the stability of the process is taken... 

Local educational institutions produce in-house English for Specific Purpose (ESP) materials according to the curriculum policies designated and developed by the Ministry of Higher Education In Iran. To this end, this book aims to be used in the Iranian setting at the tertiary level for undergraduate students majoring in Mechanical Engineering. Moreover, the style of English usage in this ESP textbook is American.
Regarding the content of the textbook, it has both thematic organizations in which the topics are relevant and includes sufficient treatment of the target language areas necessary for the students. The principle organizing approach of this textbook is theme-based. In addition,...