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Job shop scheduling with the option of jobs outsourcing
, Article International Journal of Production Research ; Volume 57, Issue 10 , 2019 , Pages 3255-3272 ; 00207543 (ISSN) ; Kianfar, F ; Sharif University of Technology
Taylor and Francis Ltd
2019
Abstract
Incorporating outsourcing in scheduling is addressed by several researchers recently. However, this scope is not investigated thoroughly, particularly in the job shop environment. In this paper, a new job shop scheduling problem is studied with the option of jobs outsourcing. The problem objective is to minimise a weighted sum of makespan and total outsourcing cost. With the aim of solving this problem optimally, two solution approaches of combinatorial optimisation problems, i.e. mathematical programming and constraint programming are examined. Furthermore, two problem relaxation approaches are developed to obtain strong lower bounds for some large scale problems for which the optimality is...
Single machine scheduling problem with batch outsourcing
, Article International Journal of Engineering, Transactions B: Applications ; Volume 35, Issue 5 , 2022 , Pages 1006-1016 ; 1728144X (ISSN) ; Kianfar, F ; Sharif University of Technology
Materials and Energy Research Center
2022
Abstract
Outsourcing as a useful strategy in the industry can be integrated into scheduling problems. Moreover, batch outsourcing is a practical assumption owing to the logistics issues for transferring the parts between the manufacturer and the subcontractors. However, this assumption is rarely addressed in the scheduling literature. In this paper, a novel single machine scheduling problem with the option of batch outsourcing is studied. The objective is to minimize the sum of the total completion time of the jobs and the total outsourcing cost. To solve the problem, first, two mixed-integer linear programming (MILP) models, named MP1 and MP2, are developed, which respectively use a straightforward...
Optimization of Construction Workshop Activities in A Piping Process
, M.Sc. Thesis Sharif University of Technology ; Shadrokh, Shahram (Supervisor)
Abstract
Piping process is the most important part of industries projects which pay attention to construction and installation of industrial pipelines and its facilities. In the meantime, due to increasing demand of industrial units to construction and development projects, planing and scheduling the piping is necessary. We review and discuss various aspects of the piping process, optimization process and the related scheduling literature that is called Flexible Job Shop Scheduling Problem. Then, to solve the problem, considering the real world assumptions, a mathematical model, is developed and a heuristic algorithm is introduced. Also, in order to determine an appropriate bound for the optimal...
Repeatability of Lithium Adsorption and Desorption on TiO2 Nanotubes from Brines
, M.Sc. Thesis Sharif University of Technology ; Askari, Masoud (Supervisor)
Abstract
Today, recycling lithium as a valuable metal from brine plays an important role in various applications such as battery manufacturing, computers, aerospace and automobiles. Among the aqueous methods available for the extraction of the lithium element in brines, ion exchange by TiO2 nanosorbents is one of the most efficient methods. In this study, first the titanium dioxide nanotubes were well synthesized by anodizing method and the nanograss created after the anodizing process were completely eliminated. Then, the effect of three cathodes of aluminum, graphite and stainless steel in order to select the best cathode and achieve a regular morphology as well as their replacement with platinum...
Bi-objective green scheduling in uniform parallel machine environments
, Article Journal of Cleaner Production ; Volume 217 , 2019 , Pages 559-572 ; 09596526 (ISSN) ; AkhavanNiaki, S. T ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Green and sustainability issues are being considered extensively in industry and in the literature. Most of the green-related effects in the manufacturing sector can be modeled by the costs associated with the production machines due to their resource consumption and/or pollutant emission, as a part of the operation cost. Accordingly, taking into account the machine processing costs alongside the other production criteria is one of the main approaches to consider green issues in the production management problems. In the same way, scheduling as one of the major operational problems in the factories can benefit this point of view to involve sustainability aspects. In this paper, the...
Full-core reactor physics analysis for accident tolerant cladding in a VVER-1000 reactor
, Article Annals of Nuclear Energy ; Volume 155 , 2021 ; 03064549 (ISSN) ; Qarani tamai, M ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Advanced accident tolerant cladding materials have brought up the potential to delay the deleterious consequences of loos of coolant accidents related to slowing down hydrogen formation from reaction of zirconium with steam in order to minimize the additional heat generation and improve fuel and cladding retention of fission products. The performance improvement offered by these advanced materials may expand the operating envelope of existing light water reactors. This paper examines the neutronic performance of the VVER-1000 light water reactor for the application of accident tolerant cladding in order to realize the endurance of severe accident conditions. This study includes a detailed...
Airflow in buildings with courtyards
, Article Iranian Journal of Science and Technology, Transaction B: Engineering ; Volume 29, Issue 2 , 2005 , Pages 187-206 ; 03601307 (ISSN) ; Bahadori, M. N ; Sharif University of Technology
2005
Abstract
The airflow rate through a two-story building with a courtyard, with and without trees, was estimated and compared with that of a building without a courtyard. The building and the courtyard were of square shapes, each 10 m to the side. The courtyard walls were 3m high and two separate trees of spherical, cylindrical and conical shapes were considered in the yard. The courtyard was directly south of the building and a wind angle of zero degree was considered when the wind was blowing directly from the south. It was found that when the wind angles were between 0 to ±90 degrees, the airflow rate through the building was reduced when compared with the building without a courtyard. The presence...
Passive cooling effects of courtyards
, Article Building and Environment ; Volume 40, Issue 1 , 2005 , Pages 89-104 ; 03601323 (ISSN) ; Bahadori, M. N ; Sharif University of Technology
2005
Abstract
The passive cooling effects of a courtyard of a small building were determined numerically, employing an energy-analysis software developed for that purpose. The passive cooling features considered were the shading effects of courtyard walls and two large trees (of various shapes) planted immediately next to the south wall of the building, the presence of a pool, a lawn and flowers in the yard, and the wind shading effects of the walls and trees. It was found that these features alone cannot maintain thermal comfort during the hot summer hours in Tehran, but reduce the cooling energy requirements of the building to some extent. They have an adverse effect of increasing the heating energy...
Unrelated parallel machine scheduling with machine processing cost
, Article International Journal of Industrial Engineering Computations ; Volume 14, Issue 1 , 2023 , Pages 33-48 ; 19232926 (ISSN) ; Akhavan Niaki, T ; Sharif University of Technology
Growing Science
2023
Abstract
In practical scheduling problems, some factors such as depreciation cost, green costs like the amount of energy consumption or carbon emission, other resources consumption, raw material cost, etc., are not explicitly related to the machine processing times. Most of these factors can be generally considered as machine costs. Considering the machine cost as another objective alongside the other classical time-driven decision objectives can be an attractive work in scheduling problems. However, this subject has not been discussed thoroughly in the literature for the case the machines have fixed processing costs. This paper investigates a general unrelated parallel machine scheduling problem...
A heuristic scheduling method for the pipe-spool fabrication process
, Article Journal of Ambient Intelligence and Humanized Computing ; Volume 9, Issue 6 , 2018 , Pages 1901-1918 ; 18685137 (ISSN) ; Shadrokh, S ; Salehian, A ; Sharif University of Technology
Springer Verlag
2018
Abstract
The pipe-spool fabrication process is a critical operational section in the piping projects that usually used to accelerate and discipline the installation process, especially, when we have a particular deadline for the project. For this reason, the fast and optimal scheduling of the fabrication activities with considering the real conditions and using manual or traditional methods is a significant problem for the decision-makers. In this paper, we use a novel linear programming model to schedule the spool fabrication activities based on the flexible job shop scheduling problem (FJSP). Because FJSP is a challengeable NP-hard problem, we solve the proposed mathematical model with a heuristic...
Multi Criteria Scheduling in Parallel Machine Environment with Cost Criterion Consideration
, M.Sc. Thesis Sharif University of Technology ; Akhavan Niaki, Taghi (Supervisor)
Abstract
The main purpose of this research is to consider the operational machine cost in the shop floor scheduling, which is not considered in the literature thoroughly. To this end, four types of problems in the parallel machine environment are studied with the objectives of minimizing makespan and total cost. Accordingly, the problems are as type of multi-objective optimization, so we choose the approach of finding Pareto optimal solutions to solve them. In these problems we have considered unrelated parallel machines, uniform parallel machines, and the cases of existence or non-existence of sequence dependent setup times and costs. In order to solve the problems, various approaches, with respect...
A study on the effects bonding temperature and holding time on mechanical and metallurgical properties of al–cu dissimilar joining by DFW
, Article Transactions of the Indian Institute of Metals ; Volume 70, Issue 1 , 2017 , Pages 125-131 ; 09722815 (ISSN) ; Paidar, M ; Youzbashi zade, H ; Sharif University of Technology
Springer India
2017
Abstract
The aim of this study was to evaluate the influence of bonding temperature and holding time on the metallurgical and mechanical properties for weld joints of 5 mm aluminum to copper using Sn interlayer. The bonding temperature varied from 500 to 600 °C whilst the holding time varied from 30 to 120 min under 8 MPa uniaxial load in 1 × 10−4 torr vacuum. The microstructure analysis, phase analysis and distribution of elements in the interface were performed by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and element map analysis. It was found that diffusion welding parameters had a significant effect on shear strength. The attained data of tensile strength tests showed...
The effect of additives on anode passivation in electrorefining of copper
, Article Chemical Engineering and Processing: Process Intensification ; Volume 46, Issue 8 , 2007 , Pages 757-763 ; 02552701 (ISSN) ; Yoozbashizadeh, H ; Sadegh Safarzadeh, M ; Sharif University of Technology
2007
Abstract
In copper electrorefining process, some additives are added to the electrolyte to improve the morphology of cathode deposits as well as the quality of products. In the present investigation, the effects of thiourea, glue and chloride ions (as additives) on the passivation of industrial copper anodes under high current densities have been reported. Experiments were conducted at 65 °C; using a synthetic electrolyte containing 40 g/l Cu2+ and 160 g/l H2SO4. Results obtained from chronopotentiometry experiments showed that increasing the concentration of chloride ion leads to increase in passivation time. The results also indicated that from a certain level on, namely 2 ppm, the increase in...
HAL-RD: Cross-correlating heterogeneous alerts and logs using resource dependencies
, Article 35th Annual ACM Symposium on Applied Computing, SAC 2020, 30 March 2020 through 3 April 2020 ; 2020 , Pages 1726-1735 ; Abadi, M ; Nowroozi, A ; ACM Special Interest Group on Applied Computing (SIGAPP) ; Sharif University of Technology
Association for Computing Machinery
2020
Abstract
Many organizations today use a variety of security and monitoring tools at various levels of defense. These tools often generate heterogeneous alerts and logs when an attack occurs. Because of the large volume and dispersion of these alerts and logs, the manual cross-correlation of them is a time-consuming and labor-intensive task. The main challenge is that heterogeneous alerts and logs generated as a result of an attack stage do not necessarily have common features, or there are no explicit relationships between them that can be used for cross-correlation. In this paper, we overcome this deficiency by presenting HAL-RD, a novel technique that uses resource dependencies to cross-correlate...
Optimizing Transmisson from Distant Wind Farms
, M.Sc. Thesis Sharif University of Technology ; Hosseini, Hamid (Supervisor)
Abstract
Wind power is site dependent and is by nature partially dispatchable. Furthermore, good wind sites are far from grid. Due to these problems, and along with the existing limitations in the transmission networks, a comprehensive analysis over an extended time is needed to properly explore all potential wind sites for wind capacity allocation. This problem is computationally expensive and decomposition methods are required to break down this problem. Here Benders decomposition approach is used, which is a popular technique for solving large-scale problems, to decompose the original problem into a master and a subproblem. The master problem is a linear problem, which allocates wind capacity to...
Identification of the Set of Single Nucleotide Variants in Genome Responsible for the Differentiation of Expression of Genes
, M.Sc. Thesis Sharif University of Technology ; Rabiee, Hamid Reza (Supervisor) ; Beigi, Hamid (Supervisor)
Abstract
Single nucleotide polymorphs, There are changes caused by a mutation in a nucleotide in the Dena sequence. Mononucleotide polymorphisms are the most common type of genetic variation. Some of these changes have little or no effect on cells, while others cause significant changes in the expression of cell genes that can lead to disease or resistance to certain diseases. Because of the importance of these changes and their effect on cell function, the relationships between these changes are also important. Over the past decade, thousands of single disease-related mononucleotide polymorphisms have been identified in genome-related studies. Studies in this field have shown that the expression of...
Synthesis & Characterization of Au-HKUST-1 Nanocomposite and Evaluation of Plasmonic Properties of Gold Nanoparticles in this Nanocomposite
, M.Sc. Thesis Sharif University of Technology ; Madaah Hosseini, Hamid Reza (Supervisor)
Abstract
In the past few years, many research works on the controllable integration of metal nanoparticles and metal-organic frameworks were done, since the obtained composite material shows a synergism effect in catalysis and photocatalysis, drug delivery applications, gas, and energy storage, as well as sensing. For the first time, in this study, we employed template-assisted growth to synthesize Au-HKUST-1 Nanocomposite. XRD analysis entirely confirms that employing this strategy in synthesizing Au-HKUST-1 was wholly successful, and the plasmonic properties of this nanostructure were studied via UV-visible spectroscopy. In the course of synthesis, gold nanoparticles with 70nm diameter were...
Synthesis of Magnetite (Fe3O4)-Avastin Nanocomposite as a Potential Drug for AMD Treatment
, M.Sc. Thesis Sharif University of Technology ; Maddah Hosseini, Hamid Reza (Supervisor) ; Delavary, Hamid (Co-Advisor)
Abstract
Age-related macular degeneration (AMD) is the most common cause of vision loss in those aged over 50. There are two main types of AMD, Wet and Dry form. Wet AMD is more severe though more treatable. There are three conventional treatments for AMD including laser therapy, surgery and intravitreal injection of anti-VEGF into the eye. Delivery of drugs to the posterior segment of the eye is still challenging and several implants and devices are currently under investigation for their ability to stimulate the retina, producing visual percepts. The application of intravitreal bevacizumab (Avastin) has expanded tremendously from the time of its introduction into ophthalmic care since 3 years ago....
Detection of Central Nodes in Social Networks
, Ph.D. Dissertation Sharif University of Technology ; Movaghar, Ali (Supervisor) ; Rabiee, Hamid Reza (Supervisor)
Abstract
In analyzing the structural organization of many real-world networks, identifying important nodes has been a fundamental problem. The network centrality concept deals with the assessment of the relative importance of network nodes based on specific criteria. Central nodes can play significant roles on the spread of influence and idea in social networks, the user activity in mobile phone networks, the contagion process in biological networks, and the bottlenecks in communication networks. High computational cost and the requirement of full knowledge about the network topology are the most significant obstacles for applying the general concept of network centrality to large real-world social...
Monte carlo modeling of magnification mode for quantitative assessment of image quality in mammography systems
, Article 2019 IEEE International Symposium on Medical Measurements and Applications, MeMeA 2019, 26 June 2019 through 28 June 2019 ; 2019 ; 9781538684276 (ISBN) ; Khodajou Chokami, H ; Vosoughi, N ; Noorvand, M ; IEEE; IEEE Instrumentation and Measurement Society; Kadir Has University (KHU); UME ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Scattered radiations are one of the most important factors in the degradation of the image quality of mammography systems. Some techniques have been proposed for the reduction of such rays. Magnification mode can be done by increasing the air gap which determined by the distance of the breast and image intensifier. It is one of the useful techniques to elevate the produced image quality due to the rejection of scattered photons. Monte Carlo N-Particle eXtended transport code (MCNPX) version 2.7.0 is a software package for the simulation of physical processes. In this work, this computer code is used for analyzing the effects of magnification mode on mammographic image quality. To this...