Endüstri Mühendisliği / Industrial Engineering
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A memetic randomkey genetic algorithm for a symmetric multiobjective traveling salesman problem
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Publisher and Date:(PergamonElsevier Science Ltd, 2008)This paper proposes a methodology to find weakly Pareto optimal solutions to a symmetric multiobjective traveling salesman problem using a memetic randomkey genetic algorithm that has been augmented by a 2opt local search. The methodology uses a targetvector approach" in which the evaluation function is a weighted Tchebycheff metric with an ideal point and the local search is randomly guided by either a weighted sum of the objectives or a weighted Tchebycheff metric. The memetic algorithm has ...

A heuristic approach for allocation of data to RFID tags: A data allocation knapsack problem (DAKP)
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Publisher and Date:(PergamonElsevier Science Ltd, 2012)Durable products and their components are increasingly being equipped with one of several forms of automatic identification technology such as radio frequency identification (RFID). This technology enables data collection, storage, and transmission of product information throughout its life cycle. Ideally all available relevant information could be stored on RFID tags with new information being added to the tags as it becomes available. However, because of the finite memory capacity of RFID tags ...

Maximal linear subspaces of strong selfdual 2forms and the Bonan 4form
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Publisher and Date:(Elsevier Science Inc, 2011)The notion of selfduality of 2forms in 4dimensions plays an eminent role in many areas of mathematics and physics, but although the 2forms have a genuine meaning related to curvature and gaugefieldstrength in higher dimensions also, their "selfduality" is something which is almost avoided above 4dimensions. We show that selfduality of 2forms is a very natural notion in higher (even) dimensions also and we prove the equivalence of some scattered and rarely used definitions in the literature. ...

Application of epidemic models to phase transitions
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Publisher and Date:(Taylor & Francis Ltd, 2012)The SusceptibleInfectedRecovered (SIR) and SusceptibleExposedInfectedRecovered (SEIR) models describe the spread of epidemics in a society. In the typical case, the ratio of the susceptible individuals fall from a value S0 close to 1 to a final value Sf, while the ratio of recovered individuals rise from 0 to Rf = 1  Sf. The sharp passage from the level zero to the level Rf allows also the modeling of phase transitions by the number of "recovered" individuals R(t) of the SIR or SEIR ...

On the Classification of Fifth Order Quasilinear Nonconstant Separant Scalar Evolution Equations of the KdVType
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Publisher and Date:(Physical Soc Japan, 2012)Fifth order, quasilinear, nonconstant separant evolution equations are of the form u(t) = A(partial derivative(5)u/partial derivative x(5)) + (B) over tilde, where A and (B) over tilde are functions of x, t, u and of the derivatives of u with respect to x up to order 4. We use the existence of a "formal symmetry'', hence the existence of "canonical conservation laws'' rho((i)), i = 1, . . . , 5 as an integrability test. We define an evolution equation to be of the KdVType, if all odd numbered ...

A MATHEMATICAL DESCRIPTION OF THE CRITICAL POINT IN PHASE TRANSITIONS
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Publisher and Date:(World Scientific Publ Co Pte Ltd, 2013)Let y(x) be a smooth sigmoidal curve, y((n)) be its nth derivative and {x(m,i)} and {x(a,i)}, i = 1, 2, ... , be the set of points where respectively the derivatives of odd and even order reach their extreme values. We argue that if the sigmoidal curve y(x) represents a phase transition, then the sequences {x(m,i)} and {x(a,i)} are both convergent and they have a common limit x(c) that we characterize as the critical point of the phase transition. In this study, we examine the logistic growth curve ...

On the Time Shift Phenomena in Epidemic Models
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Publisher and Date:(Frontiers Media Sa, 2020)In the standard SusceptibleInfectedRemoved (SIR) and SusceptibleExposedInfectedRemoved (SEIR) models, the peak of infected individuals coincides with the inflection point of removed individuals. Nevertheless, a survey based on the data of the 2009 H1N1 epidemic in Istanbul, Turkey displayed a time shift between the hospital referrals and fatalities. An analysis of recent COVID19 data and the records for Spanish flu (19181919) and SARS (20022004) epidemics confirm this observation. We use ...

A hesitant fuzzy linguistic terms setbased AHPTOPSIS approach to evaluate ERP software packages
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Publisher and Date:(Emerald Group Publishing Ltd, 2020)Purpose In this paper, two popular multiplecriteria decisionmaking (MCDM) methods with hesitant fuzzy logic approach; hesitant fuzzy analytic hierarchy process (hesitant FAHP) and hesitant fuzzy the technique for order preference by similarity to ideal solution (HFTOPSIS) are integrated as HFAHPTOPSIS to evaluating a set of enterprise resource planning (ERP) alternatives and rank them by weight to reach to the ultimate one that satisfies the needs and expectations of a company. Design/meth ...

A mathematical characterization of the gel point in solgel transition
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Publisher and Date:(IOP Publishing Ltd, 2015)We model the solgel transition in terms of SusceptibleInfectedRemoved (SIR) and SusceptibleExposedInfectedRemoved (SEIR) models and compare with experimental results. We show, numerically, that the "gel point" described as the onset of the gelation phenomena and measured experimentally, corresponds to an accumulation point of the extreme values of the derivatives of the gelation curve. We define the "critical point of a sigmoidal curve" as the limit of the points where the derivatives reach ...

On the uniqueness of epidemic models fitting a normalized curve of removed individuals
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Publisher and Date:(Springer Heidelberg, 2015)The susceptibleinfectedremoved (SIR) and the susceptibleexposedinfectedremoved (SEIR) epidemic models with constant parameters are adequate for describing the time evolution of seasonal diseases for which available data usually consist of fatality reports. The problems associated with the determination of system parameters starts with the inference of the number of removed individuals from fatality data, because the infection to death period may depend on health care factors. Then, one ...

AHPBASED APPROACH TO EVALUATE SOLAR POWER PLANT LOCATION ALTERNATIVES
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Publisher and Date:(Intl Inst Social & Economic Sci, 2016)Solar energy is the most readily available source of energy, and one of the most important sources of the renewable energy, because it is nonpolluting and helps in lessening the greenhouse effect. Main problem of establishing a solar power plant is to determine its location. In the presence of many location alternatives and evaluation criteria, a multiplecriteria decision making problem arises. In this work, the location problem will be solved by using analytic hierarchy process (AHP) to figure ...

On the uniqueness of the octonionic instanton solution on conformally flat 8manifolds
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Publisher and Date:(IOP Publishing Ltd, 2016)Let M be an 8manifold and E be an SO(8) bundle on M. In a previous paper [F. Ozdemir and A.H. Bilge, "Selfduality in dimensions 2n > 4: equivalence of various definitions and the derivation of the octonionic instanton solution", ARI (1999) 51:247253], we have shown that if the second Pontrjagin number p(2) of the bundle E is minimal, then the components of the curvature 2form matrix F with respect to a local orthonormal frame are Fij = c(ij)omega(ij), where c(ij)'s are certain functions and ...

Modeling of Wind Effects on Stratified Flows in Open Channels: A Model for the Istanbul Strait (Bosphorus)
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Publisher and Date:(2016)Stratified flows in open channels arise as a result of density or surface level differences. If the channel is connected to a basin at one or both ends, strong winds originating from the basin cause the "wind setup" effect that increases the water level at the entrance of the channel. On the other hand, along the channel, persistent winds in the upper layer flow direction lead to an increase of the drift velocity and to a decrease in upper layer flow depth. The Istanbul Strait (Bosphorus) connecting ...

Generation/transmission investment planning integrated with market equilibrium models in electricity markets
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Publisher and Date:(IEEE, 2017)This paper introduces integrated models for transmission investments anticipating the generation investments and marketclearing equilibrium. Marketclearing models for deregulated electricity markets can inform decision makers on price signals formed in the competitive market, other investor's and/or generator's behaviors underlying these price signals and new generation/transmission investment decisions. Bilevel programming problems are formed for this integrated models and reformulated by using ...

Selfduality in higher dimensions
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Publisher and Date:(IOP Publishing Ltd, 2017)Let w be a 2form on a 2n dimensional manifold. In previous work, we called w "strong selfdual, if the eigenvalues of its matrix with respect to an orthonormal frame are equal in absolute value. In a series of papers, we showed that strong selfduality agrees with previous definitions; in particular if w is strong selfdual, then, in 2n dimensions, w(n) is proportional to its Hodge dual w and in 4n dimensions, w(n) is Hodge selfdual. We also obtained a local expression of the Bonan 4form on 8 ...

Reformulations of a Bilevel Model for Detection of Tacit Collusion in Deregulated Electricity Markets
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Publisher and Date:(IEEE Computer Society, 2019)In this study, we consider a collusion model for competitive pool based electricity markets operated by an independent system operator (ISO), where it aims to prevent tacit collusion among generators. In order to determine the existence of tacit collusion in the market, we have employed the the gameTheoretic bilevel optimization model proposed by [1]. This model represents the market clearing mechanism, where generators determine their bids in order to maximize their profit while the system ...

A Comparative Study of Energy Models for Turkish Electricity Market Using LEAP
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Publisher and Date:(IEEE Computer Society, 2019)Fossil fuel thermal power plants constitute a large part of the Turkish electricity generation capacity. Turkish government has been developing several energy policy documents to evaluate how various renewable energy sources of the country can be utilized optimally in the generation of electricity within the next 30 years. This study considers three scenarios in the transition to renewable energy for Turkey; the business as usual (BAU), energy conservation (EC) and renewable energy (REN) scenarios. ...

Evaluation Of Water Supply Alternatives For Istanbul Using Forecasting And MultiCriteria Decision Making Methods
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Publisher and Date:(Elsevier Ltd, 2020)Water scarcity is one of the most serious problems of the future due to increasing urbanization and water demand. Urban water planners need to balance increasing water demand with water resources that are under increasing pressure due to climate change and water pollution. Decision makers are forced to select the most appropriate water management alternative with respect to multiple, conflicting criteria based on short and long term projections of water demand in the future. In this paper, we ...

Forecasting Models For Daily Natural Gas Consumption Considering Periodic Variations And Demand Segregation
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Publisher and Date:(Elsevier Ltd, 2020)Due to expensive infrastructure and the difficulties in storage, supply conditions of natural gas are different from those of other traditional energy sources like petroleum or coal. To overcome these challenges, supplier countries require takeorpay agreements for requested natural gas quantities. These contracts have many preclauses; even if they are not met due to low/high consumption or other external factors, buyers must completely fulfill them. A similar contract is then imposed on ...

An Intelligent Approach For The Evaluation Of Transformers In A Power Distribution Project
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Publisher and Date:(IOS Press BV, 2020)In this study, a hybrid approach is presented for the evaluation and selection of transformers in a power distribution project. Ranking transformers and selecting the best among alternatives is a complex multiple criteria decision making (MCDM) problem with various possibly conflicting quantitative and qualitative criteria. In this research, two hesitant fuzzy MCDM methods; hesitant fuzzy Analytic Hierarchy Process (hesitant FAHP) and hesitant fuzzy Preference Ranking Organization Method for ...