Sharif Digital Repository

Detection of seizure periods in an epileptic patient is an important part of health care. However, due to the variety in types of seizures and location of them, real-time seizure detection is not straight forward. In this paper, we propose a method for seizure detection from EEG signals in datasets which have both generalized and focal seizures. The proposed method is useful in the situations that we have no prior knowledge about the location of the patient's seizure and the pattern of evolution of seizure location. In the proposed method, first, the artifacts are automatically reduced by Blind Source Separation (BSS) methods. Then, the channels are clustered into two clusters. After that,... 

The development of a multiple model-based identification algorithm is addressed in this paper for nonlinear modeling of a conventional aircraft in the entire flight envelope. The dynamic model of an aircraft varies significantly depending on changes in the flight condition of the air vehicle including the altitude and the equivalent air speed. Therefore, the conventional identification approaches for generating a single nonlinear model with time-invariant parameters cannot be used in the entire flight envelope of an aircraft. Accordingly, a multiple model-based approach using nonlinear autoregressive exogenous neural networks is introduced in this paper as a powerful tool in identifying... 

Sentiment analysis, is a subfield of natural language processing that aims at opinion mining to analyze thoughts, orientation and, evaluation of users within some texts. The solution to this problem includes two main steps: extracting aspects and determining users' positive or negative sentiments with respect to the aspects. Two main challenges of sentiment analysis in the Persian language are lack of comprehensive tagged data sets and use of colloquial language in texts. In this paper we propose, a system to specify and extract sentiment words using unsupervised methods in the Persian language that also support colloquial words. Additionally, we also proposed and implemented a state-of-art... 

An online operator position prediction approach based on artificial neural network for teleoperation systems is proposed in this paper, which predicts future position of operator's hand based on current available data. The neural network gathers inputs for some time at the beginning of the operation, then is trained, and is finally exploited through the rest of the operation. Superiority of the proposed approach can be investigated from two aspects. Firstly, no limiting assumption is required in this approach in contrast with the proposed methods in the literature. Secondly, unknown operator intention can be dealt with in real time if it is not too sudden and unpredictable. Two different... 

The great surge in the research of community discovery in complex network is going on due to its challenging aspects. Dynamicity and overlapping nature are among the common characteristics of these networks which are the main focus of this paper. In this research, we attempt to approximate the granular human-inspired viewpoints of the networks. This is especially helpful when making decisions with partial knowledge. In line with the principle of granular computing, in which precision is avoided, we define the micro- and macrogranules in two levels of nodes and communities, respectively. The proposed algorithm takes microgranules as input and outputs meaningful communities in rough... 

Energy innovation is a key requirement to limit global warming and tackle climate change in the years to come. A better understanding of the public R&D mechanism is likely to improve allocation of resources for energy innovation. Thus, the present paper evaluates the impacts of public R&D and knowledge spillovers on the development of renewable energy sources. To achieve this goal, knowledge flow has been modeled as a function of public R&D expenditures, cumulative knowledge stocks and knowledge spillovers. To show the application of the model, the Nordic countries as one of the pioneers in renewable technologies have been chosen. Results show the cumulative knowledge stock will increase to... 

Using network analysis, we investigate if an industry's complex and integrated knowledge base leads to a higher spatial concentration (or dispersal)of innovative activities. This is important because the extant literature provides competing claims about how knowledge base complexity impacts on the spatial distribution of industrial innovation. To help empirically resolve this issue, we draw on longitudinal data (1970–2010)on the upstream petroleum industry and build indexes of entropy and complexity to render knowledge base dynamics, assess the spatial concentration of innovation, and study industry structural transformations. We first find a correlation – once a crucial distinction between... 

Being the second-largest country in the Middle East, Iran has a long history of civilisation during which several dynasties have been overthrown and established and health-related structures have been reorganised. Iran has had the replacement of traditional practices with modern medical treatments, emergence of multiple pioneer scientists and physicians with great contributions to the advancement of science, environmental and ecological changes in addition to large-scale natural disasters, epidemics of multiple communicable diseases, and the shift towards non-communicable diseases in recent decades. Given the lessons learnt from political instabilities in the past centuries and the... 

Twitter is among the most used microblogging and online social networking services. In Twitter, a name, phrase, or topic that is mentioned at a greater rate than others is called a «trending topic» or simply «trend». Twitter trends has shown their powerful ability in many public events, elections and market changes. Nevertheless, there has been very few works focusing on understanding the dynamics of these trending topics. In this article, we thoroughly examined the Twitter's trending topics of 2018. To this end, we accessed Twitter's trends API for the full year of 2018, and devised six criteria to evaluate our dataset. These six criteria are: lexical analysis, time to reach, trend... 

Temporal coupled mode theory (CMT) has so far been applied phenomenologically in the analysis of optical cavity-waveguide structures, and relies on a priori knowledge of the to-be-excited resonator mode. Thus a rigorous derivation from Maxwell's equations, and without any prior knowledge of the resonator type is needed. In this paper we derive temporal CMT of optical cavities coupled to waveguides. Starting from Maxwell's equations and considering a proper expansion of the modes of the waveguide and resonator, and using mode orthogonality, the temporal CMT for this structure is obtained. We show that this formulation is general and can be applied to both traveling wave and standing wave type... 

This paper presents a new implementation of adaptive beamforming algorithm that can be fully implemented on chip. It does not require the knowledge of the incoming signal direction or phase shifter characteristics. Besides, it eliminates the need for the ADC to convert the analog output signal to digital values for the microprocessor and the DAC to apply the calculated values to the control voltages of the analog phase shifters. Thus, it exhibits better convergence speed. In addition, the need for the complex and power-hungry processor is eliminated. Therefore, this implementation consumes less power. Analytical equations and constraints on system design parameters are derived, and the... 

Temporal coupled mode theory (CMT) has so far been applied phenomenologically in the analysis of optical cavity-waveguide structures, and relies on a priori knowledge of the to-be-excited resonator mode. Thus a rigorous derivation from Maxwell's equations, and without any prior knowledge of the resonator type is needed. In this paper we derive temporal CMT of optical cavities coupled to waveguides. Starting from Maxwell's equations and considering a proper expansion of the modes of the waveguide and resonator, and using mode orthogonality, the temporal CMT for this structure is obtained. We show that this formulation is general and can be applied to both traveling wave and standing wave type... 

This paper presents a new implementation of adaptive beamforming algorithm that can be fully implemented on chip. It does not require the knowledge of the incoming signal direction or phase shifter characteristics. Besides, it eliminates the need for the ADC to convert the analog output signal to digital values for the microprocessor and the DAC to apply the calculated values to the control voltages of the analog phase shifters. Thus, it exhibits better convergence speed. In addition, the need for the complex and power-hungry processor is eliminated. Therefore, this implementation consumes less power. Analytical equations and constraints on system design parameters are derived, and the... 

In this paper, a nonlinear controller, which can be updated online by means of fuzzy logic, has been proposed for tracking the trajectory of a car-like robot. The advantage of this control scheme is that it eliminates the effects of model disturbances and uncertainties, which cannot be avoided; and especially when we consider the difficult task of determining the exact kinematic and dynamic models of car-like robots. The proposed approach comprises a robust nonlinear section that uses the sliding mode control and a fuzzy section that can update, online, parameters of the nonlinear controller. The stability and the error convergence of the closed-loop system are verified through the Lyapunov... 

The great surge in the research of community discovery in complex network is going on due to its challenging aspects. Dynamicity and overlapping nature are among the common characteristics of these networks which are the main focus of this paper. In this research, we attempt to approximate the granular human-inspired viewpoints of the networks. This is especially helpful when making decisions with partial knowledge. In line with the principle of granular computing, in which precision is avoided, we define the micro- and macrogranules in two levels of nodes and communities, respectively. The proposed algorithm takes microgranules as input and outputs meaningful communities in rough... 

Purpose: The purpose of this research is to propose a framework for developing business intelligence systems (BIS). Design/methodology/approach: Following a qualitative research method, a comprehensive framework at organizational and individual level, as well as team level, was developed. Findings: The findings revealed that team-level influential factors play a more significant role in BIS development success. The results also indicate that BIS development relies on suppliers, customers and their relationships, whereas the supplier side has a more significant impact on determining successful development. Drawing on these findings, embedded knowledge, knowledge management process capability... 

In real applications of hub networks, the travel times may vary due to traffic, climate conditions, and land or road type. To facilitate this difficulty, in this paper, the travel times are assumed to be characterized by trapezoidal fuzzy variables to present a fuzzy capacitated single allocation p-hub centre transportation (FCSApHCP) with uncertain information. The proposed FCSApHCP is redefined into its equivalent parametric integer non-linear programming problem using credibility constraints. The aim is to determine the location of p capacitated hubs and the allocation of centre nodes to them in order to minimize the maximum travel time in a hub-and-centre network under uncertain... 

A non-malleable encoding scheme is a keyless encoding scheme which is resilient to tampering attacks. Such a scheme is said to be continuously secure if the scheme is resilient to attacks containing more than one tampering procedure. Moreover, such a scheme is said to have the T-tamper-detection property if any kind of tampering attack by an adversary chosen from a predetermined class of algorithms T is detected. Faust et al. have introduced a continuous non-malleable encoding scheme based on non-interactive zero-knowledge (NIZK) which is secure in a strong model for which the adversary receives the tampered codeword as a response to its tampering query if the tampered codeword is not... 

Considering their special features and numerous applications, sensor networks are noticed so much nowadays. A sub-group of these applications is underwater sensor networks, which encounter some challenges like reliable transportation, routing, MAC, positioning, limited bandwidth, high and variable propagation delay, defective underwater channels and low battery capacity. Acoustic technologies are a particular technology which can make strong underwater communications for Civilian and military applications. These networks are used in oceans for environmental monitoring, under sea discovery, unexpected events prevention, ships assisting, tactical monitoring and naval mine detection, but there... 

In this paper, an indirect adaptive fuzzy sliding mode controller for a 3-dimensional inverted pendulum as a fully actuated MIMO system is developed. This inverted pendulum, has four degrees of freedom and equations of the system are nonlinear and non-minimum phase. Thus, control of this system is a challenging issue. Accordingly, in this work, general basis of sliding mode control method with reaching rules is expressed for this system, then the fuzzy control theory is combined, and modeling uncertainties of the system are estimated by universal fuzzy approximation theory. Controller parameters are updated by a defined adaptation law to decrease the tracking error of the inverted pendulum....