Search for: cost-reduction
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    Technical assessment of ground-source, air-source, and hybrid heat pumps for single-family buildings in cold climates

    , Article 25 June 2016 through 29 June 2016 ; Volume 122 , 2016 , Pages 270-280 ; 00012505 (ISSN) ; 9781939200464 (ISBN) Eslami Nejad, P ; Hakkaki Fard, A. M ; Aidoun, Z ; Ouzzane, M ; Sharif University of Technology
    Amer. Soc. Heating, Ref. Air-Conditoning Eng. Inc 
    This paper discusses a technical comparison of a directexpansion ground-source heat pump (DX-GSHP) and an airsource heat pump (ASHP). To lower the ground heat exchanger size for cost reduction purposes, the system performance of a hybrid system is also evaluated using a supplementary air evaporator combined with the DX-GSHP. Detailed screening models previously developed for ASHPs and DX-GHSPs are first used to compare the seasonal performance of these two options for a residential building in the cold-climate city of Montreal, Canada. Then, the model is adopted for performance evaluation of the hybrid system. Additionally, different parameters including borehole total length and heat pump... 

    One-for-one period policy and a series of suppliers

    , Article 2009 International Conference on Computers and Industrial Engineering, CIE 2009, 6 July 2009 through 9 July 2009, Troyes ; 2009 , Pages 902-906 ; 9781424441365 (ISBN) Haji, R ; Pirayesh Neghab, M ; Haji, A ; Sharif University of Technology
    The purpose of this paper is to adopt and analyze a new ordering policycalled one-for-one-period policy in a multi-echelon supply chain consisting ofone retailer and a series of TV suppliers. The main advantage of adopting theone-for-one-period (7,7) ordering policy for retailers is the elimination ofuncertainty for supplier which leads to total elimination of the safety stocksat all suppliers. This in turn leads to the reduction of the total system costsand in case any supplier's ordering cost is negligible it can even eliminate theneed for him to carry any inventory. In addition to this advantage, thenumerical results show that the application of this new policy for the retailerleads to... 

    Dynamic economic evaluation of distribution automation systems

    , Article 2009 International Conference on Electric Power and Energy Conversion Systems, EPECS 2009 ; 2009 ; 9789948427155 (ISBN) Rahmani, S ; Ehsan, M ; Sharif University of Technology
    In a deregulated environment of power distribution industry, a comprehensive economic evaluation for the implementation of distribution automation (DA) systems is inevitable. Using the presented methodology in this paper and system dynamics approach, it is efficiently possible to deal with variation of the economic parameters such as the interest rate, inflation rate, energy supply cost, load growth, etc. In this paper, economic short-run and long-run impacts of DA systems are evaluated from utility point of view. Also economic benefits from customers' point of view are analyzed. A practical pricing strategy for maximizing the utility profit is suggested depending on the underlying market... 

    An overview to applicability of multilateral drilling in the Middle East Fields

    , Article Society of Petroleum Engineers - Offshore Europe Oil and Gas Conference and Exhibition 2009, OE 2009, 8 September 2009 through 11 September 2009, Aberdeen ; Volume 1 , 2009 , Pages 567-577 ; 9781615675821 (ISBN) Mirzaei Paiaman, A ; Moghadasi, J ; Sharif University of Technology
    There are several types of drilling methods to increase the productivity of a well, such as horizontal drilling, extended reach horizontal drilling and Multilateral (ML) drilling. It is thought that ML wells could be more economic with higher productivities than horizontal or extended reach horizontal wells. Advances in ML drilling promise reduced costs, greater flexibility and increased profit potential. In the last 20 years, thousands of ML wells have been drilled worldwide, but only a small percentage of the total number of wells is multilateral. The probable reason may be lack of concise information and misconceptions surrounding the costs and perceived risks. However, recent advances in... 

    An efficient method for identifying IDS agent nodes by discovering compromised nodes in MANET

    , Article 2009 International Conference on Computer and Electrical Engineering, ICCEE 2009, 28 December 2009 through 30 December 2009, Dubai ; Volume 1 , 2009 , Pages 625-629 ; 9780769539256 (ISBN) Kuchaki Rafsanjani, M ; Khavasi, A. A ; Movaghar, A ; Sharif University of Technology
    Intrusion Detection Systems (IDS) for Mobile Ad hoc NETworks (MANETs) are necessary when they are deployed in reality. In This paper, we have presented a combined method of selecting IDS agent nodes in mobile ad hoc networks. Since, the IDS agents in MANET due to more activities need to more battery power. In our method, first, compromised nodes are detected and then the nodes with the highest energy power from among valid nodes as IDS agent nodes are considered. So, with this method, some valid nodes contribute in intrusion detection activities and costs of the network monitoring will be reduced and the network lifetime will be increased. © 2009 IEEE  

    An adaptive approach for PEVs charging management and reconfiguration of electrical distribution system penetrated by renewables

    , Article IEEE Transactions on Industrial Informatics ; 2017 ; 15513203 (ISSN) Rahmani Andebili, M ; Fotuhi Firuzabad, M ; Sharif University of Technology
    An adaptive approach for distribution system reconfiguration and charging management of plug-in electric vehicles (PEV) is presented in this study. A stochastic model predictive control is applied to stochastically, adaptively, and dynamically reconfigure the system, manage the incidental charging pattern of PEVs, and deal with the variable and uncertain power of renewable energy sources. The objective function of problem is minimizing daily operation cost of system. Herein, the geography of area is considered and the behavior of PEVs' drivers (based on their income level) is modeled with respect to the value of incentive and their hourly distance from each charging station. It is shown that... 

    SMART: a scalable mapping and routing technique for power-gating in NoC routers

    , Article 2017 11th IEEE/ACM International Symposium on Networks-on-Chip, NOCS 2017, 19 October 2017 through 20 October 2017 ; 2017 ; 9781450349840 (ISBN) Farrokhbakht, H ; Kamali, H. M ; Hessabi, S
    Reducing the size of the technology increases leakage power in Network-on-Chip (NoC) routers drastically. Power-gating, particularly in NoC routers, is one of the most efficient approaches for alleviating the leakage power. Although applying power-gating techniques alleviates NoC power consumption due to high proportion of idleness in NoC routers, since the timing behavior of packets is irregular, even in low injection rates, performance overhead in power-gated routers is significant. In this paper, we present SMART, a Scalable Mapping And Routing Technique, with virtually no area overhead on the network. It improves the irregularity of the timing behavior of packets in order to mitigate... 

    An nnovative test bed for verification of attitude control system

    , Article IEEE Aerospace and Electronic Systems Magazine ; Volume 32, Issue 6 , 2017 , Pages 16-22 ; 08858985 (ISSN) Tavakoli, A ; Faghihinia, A ; Kalhor, A ; Sharif University of Technology
    A 3 DOF platform was constructed in the Georgia Institute of Technology to perform new control strategies in an experimental framework. Also in this simulator, there isn't any sensor used by a real satellite for attitude determination. The setup was structured on data transmitting and synchronization of distributed elements for ADCS tests. In such a plan, not only can different elements of the test bed be used individually, but also they can support an integrated hardware in the loop test. Accordingly, reusing the hardware sources causes a cost reduction of development. Furthermore the geometric interferences of different parts are minimized in this plan. So, the test bed can be developed... 

    An efficient and low power one-lambda crosstalk avoidance code design for network on chips

    , Article Microprocessors and Microsystems ; Volume 63 , 2018 , Pages 36-45 ; 01419331 (ISSN) Shirmohammadi, Z ; Mahdavi, Z ; Sharif University of Technology
    Crosstalk faults occurring in wires of Networks on Chip (NoCs) can seriously threaten the reliability of data transfer. One efficient way to tackle crosstalk faults is numeral-based Crosstalk Avoidance Codes (CACs). Numeral-based CACs reduce crosstalk faults by preventing specific transition patterns to occur. One-Lambda Codes (OLCs) are the most efficient types of CACs. However, the codec of OLCs imposes overheads including power consumption, critical path and area occupation to the routers of NoCs. To find overhead-efficient OLCs, this paper proposes an Algorithm for Generating OLC Numeral systems (AGON). AGON provides a tradeoff for designers in selecting overhead-efficient OLCs. Using... 

    Network and application-aware cloud service selection in peer-assisted environments

    , Article IEEE Transactions on Cloud Computing ; 2018 ; 21687161 (ISSN) Askarnejad, S ; Malekimajd, M ; Movaghar, A ; Sharif University of Technology
    There are a vast number of cloud service providers, which offer virtual machines (VMs) with different configurations. From the companies perspective, an appropriate selection of VMs is an important issue, as the proper service selection leads to improved productivity, higher efficiency, and lower cost. An effective service selection cannot be done without a systematic approach due to the modularity of requests, the conflicts between requirements, and the impact of network parameters. In this paper, we introduce an innovative framework, called PCA, to solve service selection problem in the hybrid environment of peer-assisted, public, and private clouds. PCA detects the conflicts between the...