Sharif Digital Repository

Networks-on-Chip (NoCs for short) are known as the most scalable and reliable on-chip communication architectures for multi-core SoCs with tens to hundreds IP cores. Proper mapping the IP cores on NoC tiles (or assigning threads to cores in chip multiprocessors) can reduce end-to-end delay and energy consumption. While almost all previous works on mapping consider higher priority for the application's flows with higher required bandwidth, a mapping strategy, presented in this paper, is introduced that considers multicast communication flows in addition to the normal unicast flows. To this end, multicast and unicast traffic flows are first characterized in terms of some new metrics which are... 

This work represents the efficiency of a solar desalination pond as a second stage of proposed zero discharge desalination processes to reach fresh water and also concentrated brine from the effluent wastewater of the desalination unit of Mobin petrochemical complex. So a solar desalination pond is constructed after a pretreatment unit to concentrate the softened wastewater to about 20wt%. The concentrated wastewater is as a suited feed for a forced circulation crystallizer. During one year, the effects of major parameters such as ambient temperature and solar insolation rate are investigated, experimentally. specific gravity in each layer of concentrated brine wastewater is evaluated. Also,... 

Increasing concerns about the lack of energy resources, global warming and environmental pollution have pushed the relevant organizations to develop energy saving strategies such as energy labeling programs. In this research, a new energy labeling program is developed and evaluated for the wet cooling towers in Iran. The cooling tower parameters, including its cooling capacity and the fan power consumption, are measured using an experimental setup. The experimental data are standardized to compensate the effect of the ambient wet bulb temperature on the cooling tower performance which cannot be controlled during the experiments. The results show that the cooling tower capacity and the fan... 

The growing worldwide demand for less polluting shapes of energy have led to a renewed interest in the use of Micro Combined Heat and Power (Micro CHP) technologies in the residential sector. Micro CHP have been introduced around Iran recently, and expected to diffuse more and more.In this paper, technical and economic studies for the use of Micro CHP in the different climate zones of Iran are executed. These zones are categorized in to five; Tehran, Rasht, Bandar Abbas, Ardebil and Yazd, based on weather conditions. Later on using an economic model, both annual energy savings and percentage of system profitability in each zone are calculated as well as reduction in annual emissions. It... 

The present study tries to use the methanol-silver nanofluid filled thermosyphon heat exchanger and compares the effectiveness as well as energy saving with pure methanol. Experimental results show that using methanol-silver nanofluid, leads to energy saving around 8.8-31.5% for cooling and 18-100% for reheating the supply air stream in an air conditioning system  

A literature review on the studies and applications of heat pipe heat exchanger in air conditioning systems in recent years is conducted. The related papers were grouped into two main categories and a summary of experimental and theoretical studies is presented. Based on this investigation, the application of a heat pipe heat exchanger or a thermosyphon heat exchanger in the conventional air conditioning systems is recommended as an efficient means for energy savings and dehumidification enhancement to maintain acceptable room conditions. This review shows that the literature on the application of heat pipe heat exchangers in air conditioning systems is very limited. Therefore, much more... 

Networks-on-Chip (NoCs for short) are known as the most scalable and reliable on-chip communication architectures for multi-core SoCs with tens to hundreds IP cores. Proper mapping the IP cores on NoC tiles (or assigning threads to cores in chip multiprocessors) can reduce end-to-end delay and energy consumption. While almost all previous works on mapping consider higher priority for the application's flows with higher required bandwidth, a mapping strategy, presented in this paper, is introduced that considers multicast communication flows in addition to the normal unicast flows. To this end, multicast and unicast traffic flows are first characterized in terms of some new metrics which are... 

This study presents a cost-benefit analysis of energy saving strategies for the commercial sector inTehran City. The article includes a discussion of the estimated energy demand for various energy saving scenarios. The cost-benefit analysis was performed separately for seven energy-saving scenarios based on the energy demand and supply forecasting model. According to which, energy demand of the commercial sector was considered as final consumption, which is a function of different parameters such as number of commercial units, number of electric vehicles, volume of commercial activities, labor force, etc. The research findings indicated that all of the proposed scenarios are economically... 

Increasing concerns about global warming and environmental pollution control has pushed the relevant organizations to set regulations and to develop programs for energy saving. In addition, for many high energy using appliances, energy labeling provides the end user with important data to select energy-efficient equipments and encourage the manufacturers to enhance the performance of their productions. In this research, a new energy-saving program for wet cooling towers has been developed. Considering a thermo-hydraulic analysis, a novel Energy Index (IE) has been extracted which takes all aspects of the problem into account. The present index can be used as a proper criterion for energy... 

Time redundancy (rollback-recovery) and hardware redundancy are commonly used in real-time systems to achieve fault tolerance. From an energy consumption point of view, time redundancy is generally more preferable than hardware redundancy. However, hard real-time systems often use hardware redundancy to meet high reliability requirements of safety-critical applications. In this paper we propose a hardware-redundancy technique with low energy-overhead for hard real-time systems. The proposed technique is based on standby-sparing, where the system is composed of a primary unit and a spare. Through analytical models, we have developed an online energy-management method which uses a slack... 

Sensor networks have a wide range of potential and practical application. A sensor network consists of a large number of tiny, low power and short-living sensors. Some sensor network applications require k-coverage to ensure the quality of surveillance. Meanwhile, energy is another primary concern for sensor networks. In this dissertation, an algorithm proposed which groups sensors in to disjoint subsets. Every subset cans k-cover the whole area. The subsets are scheduled to work successively. Therefore, the network lifetime is prolonged. Furthermore, sensing range is fixed. Also another algorithm, proposed which constructs some non-disjoint subsets, and in each active subset, each sensor... 

Significant energy subsidies are believed to be the main factor that has resulted in high energy intensities of Iranian industries. The Subsidy Reform Act of 2010 was directed at modifying energy consumption pattern and fostering energy efficiency enhancement. This study aims at analyzing the effect of energy subsidy reform on promoting energy efficiency in six energy intensive industries of Iran. In order to do so, the energy efficiency practices that have not been adopted after the implementation of the first phase of energy subsidy reform are investigated. Data analysis reveals that if financially interesting investments are determined as those with payback periods less than three years,... 

Wireless Sensor Networks (WSNs) have developed in recent years and are used in many different applications such as fire detection, military operations, and healthcare. Sensor nodes have the ability to sense an environment, sending and receiving information and forwarding packets from source nodes to a sink. These tasks consume large amounts of energy. In many WSN applications, delay and reliability of data delivery and the energy consumption of nodes are important design metrics. Network protocols such as medium access control (MAC) and routing should be designed to improve these metrics. In this article, we propose a new cross layer algorithm that improves the performance of WSN networks... 

This research aims to optimize a multi-zone Air Handling Unit's (AHU) energy consumption by using a Non-linear Model Predictive Control (NMPC) approach. In this paper, Genetic Algorithm (GA) and Non-linear autoregressive network with exogenous inputs (NARX) have been utilized to design NMPC for a multi-zone AHU. The NMPC problem could be divided into two main sections: internal model and the optimizer. NARX serves as the controller's internal model to predict the building's thermal dynamics. GA is then used to solve the NMPC problem and find the optimal value of the control signals at each time step. The proposed NMPC jointly minimizes energy consumption of the AHU and the deviation from the... 

Cloud computing consists of physical data centers each of which including hundreds or thousands of computers. A key enabler technology is virtualization. The Virtualization allows us to separate virtual machines in a way that each of these so-called virtualized machines can be configured with a number of hosts according to the type of application of the user. It is also possible to dynamically alter the allocated resources of a virtual machine. One of the most important challenges in terms of cloud computing is to maintain an optimized load balance in cloud environment on servers because this issue is critical for energy consumption. In this paper, we propose a hybrid method for reduction of... 

This paper presents a fault tolerant and energy efficient write-back set-associative cache, which has a heterogeneous structure. The cache architecture is based on partitioning the ways of each set into two different parts. In each set, one cache way uses SECDED code and maintains dirty blocks while the other ways employ parity bit and keep clean blocks. To evaluate the set-associative cache, SIMPLESCALAR tool and CACTI analytical model are used. The experimental results show that as the feature size decreases and the associativity increases, the energy saving of the proposed cache increases. The experimental results express that for an 8-way setassociative cache in 32nm, about 7% area and... 

Basically, charge recovery logic styles have been devised for low-power purposes. However, they have some other characteristics such as inherent pipelining mechanism, low data-dependent power consumption, and low electromagnetic radiations which are usually neglected by researchers. These properties can be useful in other application areas such as side channel attack resistant cryptographic hardware. This paper addresses these properties of charge recovery logics and examines a common one, called 2N-2N2P, as a side channel attack countermeasure by information theoretic evaluation metrics. The observed results show that the usage of this logic style leads to improve DPA-resistance as well as... 

Write-through caches potentially have higher reliability than write-back caches. However, write-back caches are more energy efficient. This paper provides a comparison between the write-back and write-through policies based on the combination of reliability and energy consumption criteria. In the experiments, SIMPLESCALAR tool and CACTI model are used to evaluate the characteristics of the caches. The results show that a write-through cache with one parity bit per word is as reliable as a write-back cache with SEC-DED code per word. Furthermore, the results show that the energy saving of the write-through cache over the write-back cache increases if any of the following changes happens: i) a... 

This study presents a novel set-up for desiccant-based cooling and dehumidification systems. In this cycle, a solid desiccant and conventional combined cooling and power (CCP) systems, based on the ejector refrigeration cycle (ERC) and the organic Rankine cycle (ORC), are integrated to provide dehumidification and cooling, simultaneously. The ERC is integrated with the ORC for devising a self-powered design which has not been done until now. The proposed integrated system is useful for replacing the peak electricity demand with the heat demand, decreasing the pressure on the power grid in humid areas. Dynamic hourly simulation of the proposed system as well as a conventional system were... 

University (Educational) buildings comprise a considerable contribution of commercial buildings energy consumption. Optimizing operational measures are widely suggested for energy saving in university buildings. Hence, in this study, a bi-level energy-efficient occupancy profile optimization method using a metaheuristic algorithm, integrated with a demand-driven control strategy adjusted with dynamic set-point temperature is proposed to optimize the energy consumption within in a university departmental building. To proceed with the proposed energy saving strategies; first, building's thermal behavior and AHU system performance are identified and modeled through Artificial Neural Networks...