Sharif Digital Repository

Selection of development methodologies according to the specifications of software development projects continues to be an important challenge for the software industry. Despite the growth of software methodologies, this problem has not been fully resolved yet. Software engineers have realized, however, that there is no general-purpose methodology which is suitable for all situations. Therefore, the necessity of Situational Method Engineering (SME) has become apparent, and engineers have started to use different methods for engineering software processes to fit the project situation at hand. Assembly-based, Extension-based and Paradigm-based approaches are the SME methods prevalently used... 

Event-based embedded systems are usually energy-constrained and also have to be highly reliable. This thesis presents a novel energy-efficient standby-sparing technique for eventbased embedded systems. It speculatively pre-executes reaction tasks prior to events, resulting in a high available slack time for energy management. Although the prediction might be wrong, we will show that in average the proposed speculative standby-sparing technique (SSS) consumes less energy compared to non-speculative techniques. We present some real-life examples of event-based embedded systems to justify practical use for the proposed technique. To evaluate SSS extensive experiments were conducted on a variety... 

In recent years, high interest in using virtualization platforms and Virtual Machines (VMs) in enterprise data centers and Clouds has significantly increased the demand for high performance data storage systems. Recent studies in virtualized platforms have suggested using high-performance storage elements such as Solid-State Drives (SSDs) as a caching layer for storage subsystems mainly built upon Hard Disk Drives (HDDs). Such studies implicitly focus on sharing and partitioning the I/O cache space between VMs, while they neglect to address other important parameters such as SSD lifetime, reliability, and cache policies, which can significantly affect the efficiency of I/O caching in terms... 

A high flexural modulus and high elasticity are essential for corrugated pipes used for underground wastewater transportation. High density polyethylene (HDPE), a semi-crystalline polymer, is commonly used for the production of these pipes. In this study, a nanocomposite approach was used in which recycled nano-silica from lead-acid battery separators was incorporated in weight fractions of 1%, 3% and 5% to increase the modulus. To improve the dispersion of the nano-silica particles in the polymer matrix and thus the mechanical properties, the nano-silica particles were surface modified with 3-aminopropyltriethoxysilane as coupling agent together with a maleic anhydride grafted HDPE... 

We study a speci?c class of black holes which are called extremal. By de?ning extremality asdouble-horizon condition and imposing ?niteness assumption, we show that the dynamics of ?eldsat the horizon decouples from the rest of space. This decoupling occurs by vanishing all radialderivatives. We show this decoupling for the extremal black holes in the theories of gravity correctedby f(R)terms.We also show that these two above conditions leads to AdS × S1 near horizon geometry2of rotating black holes. This geometry which preserve SO(2, 1) × U(1) isometry group, is recentlyused in improving the entropy function method. Finally we show that decoupled equations of horizon can be derived from a...