Sharif Digital Repository

This work presents some new optimization approaches to implementation of Medium Access Control (MAC) layer of IEEE 802.11 wireless networking protocol using general purpose DSP and gate array systems. Optimization starts at design level. The hardware/software partitioning of the MACs architecture is optimized in the sense of minimal implementation burden, while maintaining the system's functionalities and performance. The proposed partitioning and implementation technique obviates the use of any Real Time Operating System (RTOS), which leads to a simple, high speed, and low memory structure of the MACs software. Also, solutions such as using hash tables and pipeline processing are given and... 

Apnea-bradycardia (AB) is a common complication in prematurely born infants, which is associated with reduced survival and neurodevelopmental outcomes. Thus, early detection or predication of AB episodes is critical for initiating preventive interventions. To develop automatic real-time operating systems for early detection of AB, recent advances in signal processing can be employed. Hidden Markov Models (HMM) are probabilistic models with the ability of learning different dynamics of the real time-series such as clinical recordings. In this study, a hierarchy of HMMs named as layered HMM was presented to detect AB episodes from pre-processed single-channel Electrocardiography (ECG). For... 

The inherent complexities of multi-reservoir flood control systems and their operation conditions along with the improvements of optimization methods have led to a positive trend on better development of these models. This trend tends to provide the operators of these systems with more practical solutions. Although optimization models can provide appropriate solutions for operation of multi-reservoir systems, the exact implementation of these solutions in real world is not guaranteed. This arises mainly due to high level risk of flood situation, real time operation constraints, high level uncertainties of inflows that usually are overlooked in optimization models, and so on. These problems... 

In this work, a novel convex sequence framework for real-time receding horizon operation optimization of a hybrid renewable energy system integrated with optimal sizing is presented to increase the penetration rate of renewable energy in supplying the demand. The proposed framework optimizes the entire lifetime cost of a system consisting of two main steps which are 1) design & installation and 2) operation as two sequence modules. This framework is applied to a hybrid renewable energy system which includes PV, wind turbine, batteries and a diesel generator. In the operation optimization, receding horizon strategy is used to optimize the operation schedule. Mixed integer convex programming... 

In this paper, a hierarchical frequency regulation system is presented for real-time operation of the electrical grids. It includes a decentralized transactive energy system for clearing transactions of producers/consumers in real-time. The proposed system is implemented in a distributed fashion with small data communication requirement. It is proved that the proposed transactive energy system converges to the optimal power flow (OPF). An iterative method for optimizing control parameters of the proposed hierarchical frequency regulation system is also given. The proposed method is developed for high penetration of renewable energy sources (RESs) as the sizes, locations, and uncertainties of... 

This paper proposes an asymmetric model for urban public transportation networks. Predictive techniques are being developed, to allow advanced modeling and comparison with historical baseline data. The current trend is toward fewer costly microprocessor modules with hardware memory management and Real-Time Operating Systems This model is formulated as a linear programming problem using LP-solvers and is developed and simulated for a large metropolitan area of Tehran, Iran. The mathematical procedure as its quantitative results is presented. © 2008 IEEE