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quality-control
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Decision rule of repetitive acceptance sampling plans assuring percentile life
, Article Scientia Iranica ; Volume 19, Issue 3 , June , 2012 , Pages 879-884 ; 10263098 (ISSN) ; Niaki, S. T. A ; Rasool, M ; Fallahnezhad, M. S ; Sharif University of Technology
2012
Abstract
In this research, Repetitive Group Sampling (RGS) plans are developed for the Weibull and generalized exponential distributions. To design the proposed plans, the median of a life-time is first used as the quality parameter. Then, a decision-making framework is developed, based on first and second type errors. Next, based on acceptable and limiting quality level criteria, tables are obtained to select the parameters of the proposed decision-making framework. The advantages of the proposed method over single sampling plans are discussed at the end
A particle swarm optimization approach on economic and economic-statistical designs of MEWMA control charts
, Article Scientia Iranica ; Volume 18, Issue 6 , December , 2011 , Pages 1529-1536 ; 10263098 (ISSN) ; Malaki, M ; Ershadi, M. J ; Sharif University of Technology
2011
Abstract
Control charts are the best tools to monitor main process parameters, and the Multivariate Exponentially Weighted Moving Average, MEWMA, type of this tool is used when there are several correlated quality characteristics to be monitored simultaneously where detecting small deviations of the characteristics is desired. In this paper, the models of both the economic and the economic-statistical design problems of MEWMA control charts are solved by a Particle Swarm Optimization (PSO) approach. The comparison study between the economic and the economic-statistical designs shows better statistical performances of the economic-statistical design with negligible increase in cost. Furthermore, in...
Comparative analysis of speech dereverberation in noisy acoustical environments
, Article 2015 28th IEEE Canadian Conference on Electrical and Computer Engineering, CCECE 2015, 3 May 2015 through 6 May 2015 ; Volume 2015-June, Issue June , June , 2015 , Pages 1248-1253 ; 08407789 (ISSN) ; Ghorshi, S ; Sarafnia, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
Reverberated speech signals in noisy acoustical environments cause some problems such as reducing speech intelligibility, distinguishing speakers, locating source, quality for hands-free telephony, hearing aid, etc. Adaptive filters can be applied to suppress the interfering signals and reduce the reverberation effects or to dereverberate the received speech signals at microphone. In this paper, Bayesian State-Space Kalman and Wiener filters have been employed to reduce the effect of noise on received speech signal and their results are compared. Also, a dereverberation method is proposed by applying an inverse filter to the received speech signals to reduce the effect of reverberation on...
Towards a self-adaptive service-oriented methodology based on extended SOMA
, Article Journal of Zhejiang University: Science C ; Volume 16, Issue 1 , 2015 , Pages 43-69 ; 18691951 (ISSN) ; Moaven, S ; Habibi, J ; Beigi, G ; Naser Shariat, M ; Sharif University of Technology
Abstract
We propose a self-adaptive process (SAP) that maintains the software architecture quality using the MAPE-K standard model. The proposed process can be plugged into various software development processes and service-oriented methodologies due to its explicitly defined inputs and outputs. To this aim, the proposed SAP is integrated with the service-oriented modeling and application (SOMA) methodology in a two-layered structure to create a novel methodology, named self-adaptive service-oriented architecture methodology (SASOAM), which provides a semi-automatic self-aware method by the composition of architectural tactics. Moreover, the maintenance activity of SOMA is improved using...
Towards a self-adaptive service-oriented methodology based on extended SOMA
, Article Frontiers of Information Technology and Electronic Engineering ; Volume 16, Issue 1 , 2015 , Pages 43-69 ; 20959184 (ISSN) ; Moaven, S ; Habibi, J ; Beigi, G ; Naser Shariat, M ; Sharif University of Technology
Abstract
We propose a self-adaptive process (SAP) that maintains the software architecture quality using the MAPE-K standard model. The proposed process can be plugged into various software development processes and service-oriented methodologies due to its explicitly defined inputs and outputs. To this aim, the proposed SAP is integrated with the service-oriented modeling and application (SOMA) methodology in a two-layered structure to create a novel methodology, named self-adaptive service-oriented architecture methodology (SASOAM), which provides a semi-automatic self-aware method by the composition of architectural tactics. Moreover, the maintenance activity of SOMA is improved using...
Power and voltage control in a grid-connected microgrid system with a back-to-back converter
, Article 6th Annual International Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2015, 3 February 2015 through 4 February 2015 ; 2015 , Pages 468-473 ; 9781479976539 (ISBN) ; Mokhtari, H ; Hamzeh, M ; Asbafkan, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This paper proposes to use a back-to-back converter as the interlink between a utility grid and a microgrid. To justify this proposal, two modes of operation are explained and the benefits of the back-to-back converter over conventional static switches are shown. In mode-1, the inter-link converter injects prespecified amounts of active and reactive power to the microgrid. This mode is identified as PQ control mode. Mode-2 is the voltage control mode in which, the back to back converter controls the voltage of the microgrid and maintains the power quality of the current drawn from the utility grid in spite of nonlinear and unbalanced loads in the microgrid
Data quality improvement using fuzzy association rules
, Article ICEIE 2010 - 2010 International Conference on Electronics and Information Engineering, Proceedings, 1 August 2010 through 3 August 2010 ; Volume 1 , August , 2010 , Pages V1468-V1472 ; 9781424476800 (ISBN) ; Pedram, M. M ; Alishahi, M ; Badie, K ; Sharif University of Technology
2010
Abstract
The activities and decisions of organizations and companies are based on data and the information obtained from data analysis. Data quality plays a crucial role in data analysis, because the incorrect data leads to wrong decisions. Nowadays, improving the data quality manually is very difficult and in many cases is impossible as data quality is one of the complicated and non-structured concepts and data refinement process can not be done without the help of professional domain experts, and detection and correction of errors require a thorough knowledge in the related domain of the data. Thus, the necessity of using (semi-)automatic methods is discussed to find data defects and errors and...
The addition of data aggregation to non cluster based SPEED routing algorithm while keeping the functionality of available techniques inorder to increase QoS
, Article ; Volume 2 , April , 2010 , Pages V2696-V2700 ; ICCET 2010 - 2010 International Conference on Computer Engineering and Technology, Proceedings, 16 April 2010 through 18 April 2010 ; 9781424463503 (ISBN) ; Roustaei, R ; Movaghar, A ; Sharif University of Technology
2010
Abstract
Data aggregation is a technique that is used to decrease extra and repetitive data in cluster based routing protocols. As we know SPEED routing algorithm is based on service quality and dose not perform data aggregation. In this article, we try to add an data aggregation technique to the available techniques without interfering with the functions of previous ones. The idea involves virtual configuration of sensors and specification of an individual ID to the created data by the sensors in each region, then data aggregation in relay node is done by this ID, resulting in less energy consumption, lower traffic and repeated data, an increase in network lifetime and better quality of service
The addition of data aggregation to SPEED routing algorithm while keeping the functionality of available techniques
, Article 2nd International Conference on Future Networks, ICFN 2010, 22 January 2010 through 24 January 2010 ; January , 2010 , Pages 349-353 ; 9780769539409 (ISBN) ; Yousefi Fakhr, F ; Movaghar, A ; Sharif University of Technology
2010
Abstract
Data aggregation is a technique that is used to decrease extra and repetitive data in cluster based routing protocols. As we know SPEED routing algorithm is based on service quality and dose not perform data aggregation. In this article, we try to add an data aggregation technique to the available techniques without interfering with the functions of previous ones. The idea involves virtual configuration of sensors and specification of an individual ID to the created data by the sensors in each region, then data aggregation in relay node is done by this ID, resulting in less energy consumption, lower traffic and repeated data, an increase in network lifetime and better quality of service
A study on vertical motions of high-speed planing boats with automatically controlled stern interceptors in calm water and head waves
, Article Ships and Offshore Structures ; Volume 10, Issue 3 , 2015 , Pages 335-348 ; 17445302 (ISSN) ; Seif, M. S ; Abbaspoor, M ; Sharif University of Technology
Abstract
The controllable flaps and interceptors in planing crafts not only may reduce the resistance, but also could be designed to make a boat run at or near optimum attitude in various environments, which results in a reduction in both resistance and vertical motion in waves. Planing vessels suffer from porpoising instability and violent vertical motion at high forward speeds. The controllable flaps and interceptors can be used to control and reduce the vertical motion of planing crafts. In the present study, the impact of controlled interceptors on a planing craft seakeeping quality is investigated through application of experimental and theoretical methods. In the experimental part of the study,...
Total flow time minimization in a flowshop sequence-dependent group scheduling problem
, Article Computers and Operations Research ; Volume 37, Issue 1 , 2010 , Pages 199-212 ; 03050548 (ISSN) ; Logendran, R ; Skandari, M. R ; Sharif University of Technology
Abstract
We have developed a mathematical programming model for minimizing total flow time of the flow shop sequence dependent group scheduling (FSDGS) problem, typically classified as Fm|fmls, Splk, prmu|∑Cj. As the problem is shown to be strongly NP-hard, a tabu search (TS) algorithm as well as a hybrid ant colony optimization (HACO) algorithm have been developed to heuristically solve the problem. A lower bounding (LB) method based on the Branch-and-Price algorithm is also developed to evaluate the quality of the metaheuristic algorithms. In order to compare the performance of metaheuristic algorithms, random test problems, ranging in size from small, medium, to large are created and solved by...
Toward a collaborative method for knowledge management of software architectural decisions based on trust
, Article 12th International Conference on Fuzzy Systems and Knowledge Discovery, 15 August 2015 through 17 August 2015 ; 2015 , Pages 828-834 ; 9781467376822 (ISBN) ; Moaven, S ; Habibi, J ; Alidousti, R
Institute of Electrical and Electronics Engineers Inc
Abstract
Design and implementation of Architecture is a knowledge-driven process. Evaluation and verification the knowledge, in order to ensure its quality, have important role in improving overall design process. Furthermore, Architectural decision making is a complex and multi-criteria decision making problem in which multiple stakeholders make decisions from their perspectives causing overlaps and conflicts in the adopted decisions. Therefore, the requirement for strategies to manage these issues and also to improve coordination and cooperation among the various stakeholders to improve the overall process design is necessary. In this regard, there have been several activities that focus on...
A new approach to improve quality of service in SPEED routing protocol in wireless sensor network through data aggregation
, Article 2nd International Conference on Environmental and Computer Science, ICECS 2009, 28 December 2009 through 30 December 2009 ; 2009 , Pages 393-397 ; 9780769539379 (ISBN) ; Zohrevandi, E ; Hassani, K ; Movaghar, A ; Sharif University of Technology
Abstract
SPEED routing algorithm is a service quality based algorithm in which data aggregation dose not happen. In this article, data aggregation has been added to the conventional technique in SPEED algorithm. The idea involves virtual configuration of sensors and specification of an individual ID to the created data by the sensors in each region, then data aggregation in relay node is done by this ID, resulting in less energy consumption, lower traffic and repeated data, an increase in network lifetime and better quality of service. © 2009 IEEE
Optimal acceptance sampling policy considering Bayesian risks
, Article Communications in Statistics - Theory and Methods ; Volume 46, Issue 11 , 2017 , Pages 5228-5237 ; 03610926 (ISSN) ; Fallah Nezhad, M. S ; Jafari, R ; Sharif University of Technology
Taylor and Francis Inc
2017
Abstract
In this paper, we propose a sampling policy considering Bayesian risks. Various definitions of producer's risk and consumer's risk have been made. Bayesian risks for both producer and consumer are proven to give better information to decision-makers than classical definitions of the risks. So considering the Bayesian risk constraints, we seek to find optimal acceptance sampling policy by minimizing total cost, including the cost of rejecting the batch, the cost of inspection, and the cost of defective items detected during the operation. Proper distributions to construct the objective function of the model are specified. In order to demonstrate the application of the proposed model, we...
Evaluating the capability of distribution networks to maintain power quality and voltage level, case study: alborz electric power distribution company
, Article IET Generation, Transmission and Distribution ; Volume 12, Issue 16 , 2018 , Pages 3883-3891 ; 17518687 (ISSN) ; Rezaie, K ; Fotuhi Firuzabad, M ; Sharif University of Technology
Abstract
Distribution system operators that seek operational excellence are supposed to design and implement capable processes throughout their value stream and assess how well their real services match the design specifications. Process capability analysis is a critical stage in systematic and sophisticated quality engineering approaches such as six sigma, which are based on quantitative studies. The capability of a distribution network to maintain the power quality and voltage level within an acceptable range is one of the most important aspects of design and utilisation of electricity distribution network. Capability analysis has been successfully used in the previous studies to assess the quality...
Human–robot facial expression reciprocal interaction platform: case studies on children with autism
, Article International Journal of Social Robotics ; Volume 10, Issue 2 , April , 2018 , Pages 179-198 ; 18754791 (ISSN) ; Taheri, A ; Alemi, M ; Meghdari, A ; Sharif University of Technology
Springer Netherlands
2018
Abstract
Reciprocal interaction and facial expression are some of the most interesting topics in the fields of social and cognitive robotics. On the other hand, children with autism show a particular interest toward robots, and facial expression recognition can improve these children’s social interaction abilities in real life. In this research, a robotic platform has been developed for reciprocal interaction consisting of two main phases, namely as Non-structured and Structured interaction modes. In the Non-structured interaction mode, a vision system recognizes the facial expressions of the user through a fuzzy clustering method. The interaction decision-making unit is combined with a fuzzy finite...
A single-retailer multi-supplier multi-product inventory model with destructive testing acceptance sampling and inflation
, Article Journal of Industrial and Production Engineering ; September , 2018 ; 21681015 (ISSN) ; Akhavan Niaki, S. T ; Farhangi, M ; Mahdavi, I ; Sharif University of Technology
Taylor and Francis Ltd
2018
Abstract
In this paper, a multi-product inventory problem is investigated in which a retailer buys items from different suppliers based on their purchasing costs and defective rates. Due to the warehouse and staff constraints involved, the inventory cycle consists of two parts. The first part corresponds to a screening period in which a destructive testing acceptance-sampling plan is used to accept or reject a lot. The other part is for selling the items. In the screening period, a lot that is rejected is returned to the suppliers where another lot is claimed for substitution at no cost. Shortage occurs during the screening period and the defective items are sold at a lower price at the end of the...
Multirate, differentiated-qoS, and multilevel fiber-optic CDMA system via optical logic gate elements
, Article Journal of Lightwave Technology ; Volume 27, Issue 19 , 2009 , Pages 4348-4359 ; 07338724 (ISSN) ; Ghaffari, B. M ; Salehi, J. A ; Sharif University of Technology
2009
Abstract
In this paper, we present a novel multirate, differentiated quality of service (QoS) optical CDMA (OCDMA) system using multilevel signaling technique. The emphasis is on OCDMA systems employing multi-length variable-weight optical orthogonal codes (MLVW-OOC) as signature sequence. We begin by presenting a two-class variable-weight OCDMA system in which all users have the same energy level in one bit duration. As a consequence, high weight users transmit their corresponding optical pulses at a lower power while low weight users transmit their corresponding optical pulses at a higher power level. We show that using this multilevel signaling technique, while employing the well known optical AND...
A transformation-based multivariate chart to monitor process dispersion
, Article International Journal of Advanced Manufacturing Technology ; Volume 44, Issue 7-8 , 2009 , Pages 748-756 ; 02683768 (ISSN) ; Akhavan Niaki, T ; Abdollahian, M ; Hosseinifard, Z ; Sharif University of Technology
2009
Abstract
Multivariate monitoring techniques such as multivariate control charts are used to control the processes that contain more than one correlated characteristic. Although the majority of previous researches are focused on controlling only the mean vector of multivariate processes, little work has been performed to monitor the covariance matrix. In this research, a new method is presented to detect possible shifts in the covariance matrix of multivariate processes. The basis of the proposed method is to eliminate the correlation structure between the quality characteristics by transformation technique and then use an S chart for each variable. The performance of the proposed method is then...
Tolerance–reliability analysis of mechanical assemblies for quality control based on Bayesian modeling
, Article Assembly Automation ; Volume 39, Issue 5 , 2019 , Pages 769-782 ; 01445154 (ISSN) ; Ghaderi, A ; Sharif University of Technology
Emerald Group Publishing Ltd
2019
Abstract
Purpose: The purpose of this paper is to present a new efficient method for the tolerance–reliability analysis and quality control of complex nonlinear assemblies where explicit assembly functions are difficult or impossible to extract based on Bayesian modeling. Design/methodology/approach: In the proposed method, first, tolerances are modelled as the random uncertain variables. Then, based on the assembly data, the explicit assembly function can be expressed by the Bayesian model in terms of manufacturing and assembly tolerances. According to the obtained assembly tolerance, reliability of the mechanical assembly to meet the assembly requirement can be estimated by a proper first-order...