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Energy Management Technique with the Consideration of Time-Utility Functions for Soft Real-Time Embedded Systems
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Temporary or permanent overload commonly occurs in soft real-time systems. In such situations,the scheduler cannot guarantee the completion of all tasks prior to their deadlines.Hence, some tasks are usually aborted before or during the execution with the aim of maximizing system utility. For this purpose, time-utility function (TUF) of tasks is used to determine how to maximize the accrual utility of the system. Tasks which can provide more utility are more preferable for execution. Previous works on utility accrual maximizing algorithms have not considered memory allocation in accruing utility of soft real time systems. In this thesis, we present an online scheme for multicore embedded...
Clustering Data Streams using Core-Sets
, M.Sc. Thesis Sharif University of Technology ; Zarei, Alireza (Supervisor)
Abstract
We design a new algorithm for clustering data streams in any fixed di- mension, that use the framework of core-set to summarize data, in order to reduce the complexity of computation. Clustering is to separate data into distinct sets called clusters, which objects in the same cluster has the most similarity and objects in the different clusters has the least similarity.This problem has many application in the areas such as: machine learning,image processing, financial and stock transactions. Data stream has recently emerged as an important concept because in many applications, data is inherently streaming over a network or the data base is extremely large and sequential access is way faster...
Line Simplifcation Using the Hausdorff Distance as Error Metric
, M.Sc. Thesis Sharif University of Technology ; Zarei, Alireza (Supervisor)
Abstract
Due to recent advancements and wide usage of location detection devices, huge amount of data are collected by GPS and cellular technologies which exhibits moving objects trajectories. Using this information, it is possible to track a set of objects over a long period of time, as happens for instance in studying animal migration. Always, in these situations it is undesirable or even impossible (due to process and storage limits) to store the complete stream of positioning data. Then, simplifying a trajectory as a data reduction technique is the option for resolving such problems. Moreover, there is an increasing interest in queries capturing ”aggregate” behavior of trajectories as groups like...
Distributed Optimal Control Based on an Efficient Method for Communication
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Alireza (Supervisor)
Abstract
This thesis is concerned with an optimal trade-off between communication overhead and the number and size of neighborhoods in a distributed optimal control technique for large-scale systems that is based on the Jacobi iteration and two-layer architecture for communication. Although this method efficiently reduces computational overhead, continuous and proper data transfer between subsystems that are very often far from each other, is required to achieve an acceptable performance. However, limited transmission bandwidth and short communication range result in significant communication overhead. This causes significant time latency between measurement and applied calculated control actions,...
Location and Scheduling Trucks at Cross Docking Systems
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
Given the increased competition in supply chains and enlargement of their scale along with increasingly significant role of distribution systems, design and optimization of novel systems with comprehensive approaches in a timely manner has become important more than ever. One of such modern, efficient systems is cross docking in which the distribution network is omitted and thus operations are carried out faster and the productivity is increased. In this system, processes like packaging is done in cross docking and the goods and products are directly sent to customers. This study investigates a long-term and a short-term approach to the design of in two distinct problems. In the first...
Behavior of a Single-layer Latticed Cylinder Steel Shell with a Long Span under Wind Load
, M.Sc. Thesis Sharif University of Technology ; Khalu, Alireza (Supervisor)
Abstract
Single-layer steel grid shell structures are a good structural solution to new buildings by specific properties that are required by long-span structures and provide at the same time the opportunity to produce immense verity of design shapes and free form architecture; complex curved surfaces expect to be covered with low weight material. A grid shell is essentially a shell with its structure concentrated into individual linear element in relatively thin grid compared to the overall dimension of the grid shell. This research investigates single-layer grid structures with emphasis on design of load details. The application of single-layer for transparent structures enhances use of glazed...
Peak Power Management in Fault-tolerant Embedded Systems
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Technology scaling allows integrating multiple cores onto a single chip to make the mainstream for advanced embedded systems. However, technology scaling is envisaged to aggravate the reliability of on-chip systems due to increasing transient fault rate due to lower voltages and shrinking transistor dimensions that lead to smaller critical charges. Transient faults are typically resulted due to high-energy particle strikes in hardware and manifest as bit flips. Multi-core systems provide a great opportunity to implement reliability mechanisms such as redundant multithreading (RMT) and process level redundancy. Task replication (e.g. RMT) is a well-established technique to achieve high...
Exploiting the Intrinsic Redundancy of Multicore Platforms to Achieve Low-power Fault-tolerance in Embedded Applications
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
VLSI technology scaling has resulted in the integration of a larger number of cores in a single chip in successive technology nodes, offering a great potential to realize task-level redundancy for reliability enhancement in safety-critical applications. However, since battery technology no longer advances commensurately with integration density, multi-core platforms may have limited utility in battery-powered embedded systems. In this thesis, we propose an energy-budget-aware reliability management (enBudRM) method for multi-core embedded systems featuring hybrid energy source (with renewable and non-renewable energy sources). Our method is composed of two phases. In the offline phase, we...
Human Capital Management Using a Quantitative (Value Engineering) Approach in Projects
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
Project is defined as all activities with a definite beginning (start) and end (finish) aiming to achieve a defined target through defined resources. Literature reviews in the field of project management have shown the importance of project management capabilities for evaluation and optimization. There are many factors in project management which can lonely disrupt the timing and progress of the project. One of the most important factors that in effective and unfortunately has been less measured due to its intangible characteristic in the project is known to be the "human factor". This factor is involved from the first day a project starts and will continue till the end of the project....
Exploiting Imprecise Non-volatile Memories for Soft Real-time Embedded Systems to Achieve Low Energy Consumption
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Spin-Transfer-Torque-RAM (STT-RAM) has recently been widely accepted as a promising replacement for SRAM technology through the technology scaling due to its high density, zero standby power and comparable-to-SRAM read access latency. However, there are two major obstacles to use STT-RAM, namely, high write access latency and energy. In this study, we propose two approaches to solve these challenges in embedded systems. The conventional latency of the STT-RAM write operation is 10ns and lowering the write latency causes the required write current exponentially increase, leading to a larger memory cell area and a shorter memory lifetime. As the first proposed method, we have assessed the...
The Application of Fuzzy Customer Clustering Results in Distribution Fleet Assignment to Customer Demands Considering Sales and Distribution Simultaneously
, M.Sc. Thesis Sharif University of Technology ; Haji, Alireza (Supervisor)A Finite Element Study on Seismic Behavior of Various Concrete Column Retrofitting Methods
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
In recent years, in order to investigate the structural performance in seismic zones, concrete column reinforcement and observing their behavior under cyclic loading have attracted considerable attentions. The ductility and energy absorption capability of structure play an important role in structural performance against earthquake and consequently its failure patterns. A new chapter of these investigations has begun by the reinforcement of the concrete members, a major part of which is concerned with the confinement of concrete members in order to increase their ductility and energy absorption against the forces induced by earthquake. In this study, three prominent methods of concrete...
Numerical Analysis on Flexural Behavior of Concrete Beams Reinforced with FRP bars
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
The main problem of steel-reinforced concrete structures is corrosion of steel reinforcements which leads to premature failure of the concrete structures. This problem costs a lot annually to rehabilitate and repair these structures. In order to improve the longterm performance of reinforced concrete structures and for preventing this corrosion problem, Fiber Reinforced Polymer (FRP) bars can be substituted of conventional steel bars for reinforcing concrete structures. This study is a numerical study to evaluate structural behavior of the simply supported concrete beams reinforced with FRP bars in comparison with steel-reinforced concrete beams. The commercial Finite Element Modeling...
Data Allocation for Scratch-pad Memory on Embedded Multi-core Systems to Achieve Predictability and to Reduce Wcet
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Many embedded multicore systems can benefit from a memory hierarchy to bridge the processor/memory speed gap. Embedded systems usually utilize a cacheless architecture to avoid the unpredictable behavior. Unlike caches, scratchpad memories (SPM) are software controlled and hence the execution time of applications on such systems can be accurately predicted. Scheduling the tasks of an embedded multicore application and partitioning the available SPM budget among these cores are two critical issues in such systems. Often, these are considered separately, such a decoupled approach may miss better quality schedules. In this paper, we present an integrated approach to task scheduling and SPM...
Synthesis, Characterization and Photocatalytic Application of ZnO/g- C3N4 Composite Nanorods Fabricated by Combined Sol Gel-Hydrothermal Methods
, M.Sc. Thesis Sharif University of Technology ; Moshfegh, Alireza (Supervisor)
Abstract
Because of the working conditions of semiconductors at ambient temperature and pressure, degradation of organic pollutants through semiconductors photocatalysis has attracted the interest of many researchers. Because of its large exciton binding energy,high chemical and physical stability,high electron and hole mobility, and low cost; zinc oxide, an n-type semiconductor with 3.2 eV direct band gap, is widely used in applications such as photocatalysts, solar cells, and light-emitting diodes. Among various morphologies of ZnO, 1D nanostructures such as nanowires and nanorods have recieved much attention due to their high surface to volume ratio. However, the application of ZnO as a...
Reliability Guaranteed Energy Management in Safety-Critical Systems
, M.Sc. Thesis Sharif University of Technology ; Ejlali, Alireza (Supervisor)
Abstract
Mixed-criticality systems are introduced due to industrial interest to integrate different types of functionalities with varying importance into a common and shared computing platform. Low-energy consumption is vital in mixed-criticality systems due to their ever-increasing computation requirements and the fact that they are mostly supplied with batteries. In this thesis, we propose a novel reliability-aware energy management approach and three methods, Fair-DVFS, Stretch, and Combined Fair-DVFS/Stretch in which energy management targets non-safety-critical functionalities. The Fair-DVFS method lowers energy consumption by evenly distributing slack times between low-criticality tasks while...
A Model for the Selection and Prioritization of Project Portfolio in the Project-Based Organizations
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
During recent years a variety of decision making models for project selecting and priorities have been developed. Most of these models used quantitative indicators for projects evaluating and focused on financial and economic indicators. In this project, a decision support system for project portfolio management in construction industry has been developed. The most important feature of this model that distinct it from others is its relationship with the organization's strategies. On one hand, this model focuses on the organization to ensuring that the projects selected for investment, meet the portfolio strategy and on the other hand, it focuses on project management to delivering projects...
Design and Development of the Automated Irrigation Channel Pilot
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Alireza (Supervisor)
Abstract
The present thesis is concerned with design and development of automated irrigation system pilot. This system is obtained by equipping each regulating gate of irrigation network with a controlling hardware. This hardware is designed and developed in this project for Iran’s regulating gate, which are either slide gate or radial gate. This hardware consists of a) Ultrasonic sensor for measure gate upstream water level, b) Wireless modem for exchanging measurements between automated gates, c) controller, d) Electric motor and driver, e) shaft encoder and f) adaptor. The satisfactory performance of this hardware is shown via several experiments on the pilot
Numerical Study of Stiffener Effects on Composite Shear Wall Performance
, M.Sc. Thesis Sharif University of Technology ; Khaloo, Alireza (Supervisor)
Abstract
Concrete filled double-steel-plate (CFDSP) composite wall is a new lateral resisting system that recently used in design and strengthening of high-rise buildings. This CFDSP composite wall is composed of concrete filled steel tubular columns at the two boundaries and concrete filled double-steel-plate wall body. The main advantage of this system is the interaction between steel and concrete which delays local buckling of steel plates. Also, steel jacket increases the strength of concrete in result of confinement effects. Furthermore, these systems have lower thickness compared to ordinary concrete shear walls. Hence, they have less structural weight which reduces the earthquake force....
A Finance-Inventory Modeling in Supply Chain with Delay in Payments
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
This thesis deals with the financial risk management and coordination of supply chain members. To investigate this issue, two echelon supply chain consisting of one manufacturer and one retailer with a newsvendor inventory policy for a period is considered. The mathematical modeling has been used to find the exact answer. MATLAB software for solving and scenario generation is used for the analysis. In the proposed method, financial risk management, partial trade credit policy, coordination of supply chain members and cash discount for retailers, have been considered. According to the proposed method, the manufacturer can determine immediate payment at the start of the trade credit period...