Browsing by Publisher "Elsevier"
Now showing items 1-20 of 36
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An analysis of price spikes and deviations in the deregulated Turkish power market
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Publisher and Date:(Elsevier, 2019)The successful operation of a real time market is related to the planning in the day ahead market. We analyze the day ahead and real time market data for the Turkish power market for the period 2012-2015 to classify price spikes and their causes. We also focus on the levels of deviation between the day ahead market values and the real time market values. We define price deviation and load deviation ratios to measure the level of deviation both in price and demand. The analysis for the load is based ...
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Assortment optimization with log-linear demand: Application at a Turkish grocery store
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Publisher and Date:(Elsevier, 2019)In retail sector product variety increases faster than shelf spaces of retail stores where goods are presented to consumers. Hence assortment planning is an important task for sustained financial success of a retailer in a competitive business environment. In this study we consider the assortment planning problem of a retailer in Turkey. Using empirical point-of-sale data a demand model is developed and utilized in the optimization model. Due to nonlinear nature of the model and integrality ...
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Characterization of MWCNT-TiO2 Qps and TiO2 QDs in self-assembled films
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Publisher and Date:(Elsevier, 2017)In this study the solution which includes TiO2 quantum dots (QDs) was mixed with the multi-wall carbon nanotubes (MWCNTs) to prepare MWCNT-TiO2 QDs composite films. The effect of microstructures on the structural and optical properties of MWCNT-TiO2 QDs composite films was evaluated. The activation energy for crystallite growth of TiO2 QDs which are produced in brookite phases was calculated as 20.3 kJ/mol. The properties of MWCNT-TiO2 QDs composite films were characterized by X-ray diffraction ...
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Corporate risk-taking in developed countries: The influence of economic policy uncertainty and macroeconomic conditions
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Publisher and Date:(Elsevier, 2020)Using 74,974 firm-year observations covering 15 developed European countries over the time period 1999-2017, this paper explores the effect of economic policy uncertainty on corporate risk-taking. The findings indicate that firms become more risk averse with an economic policy uncertainty shock. The relationship is valid under idiosyncratic and earnings volatility risk measures, regardless of whether the macroeconomic condition is favorable or not. Moreover, the competition level in the industry ...
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Discovery of new azoles with potent activity against Candida spp. and Candida albicans biofilms through virtual screening
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Publisher and Date:(Elsevier, 2020)Systemic candidiasis is a rampant bloodstream infection ofCandidaspp. andC. albicansis the majorpathogen isolated from infected humans. Azoles, the most common class of antifungals which sufferfrom increasing resistance, and especially intrinsically resistant non-albicans Candida(NAC) species, actby inhibiting fungal lanosterol 14a-demethylase (CYP51). In this study we identified a number of azolecompounds in 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol/ethanone oxime ester structurethrough ...
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Does mood affect institutional herding?
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Publisher and Date:(Elsevier, 2020)Drawing on a unique data set of daily portfolio holdings for Turkish mutual funds we investigate the relationship between mood and institutional herding on the premises of various established mood proxies (weekend effect; holiday effect; Ramadan; sunshine). Results indicate that fund managers in Turkey herd significantly, with their herding growing in magnitude as the number of active funds per stock rises and appearing stronger on the buy-than the sell-side. Although the relationship of mood with ...
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Efficiency analysis of emergency departments in metropolitan areas
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Publisher and Date:(Elsevier, 2020)The demand in the healthcare industry is increasing exponentially due to aging population of the world and this is leading to a rapid increase in the cost of healthcare. The emergency departments of the hospitals are the frontline of health care systems and play an additional critical role in providing an efficient and high-quality response for patients. The overcrowding at the emergency departments due to growing demand results in a situation where the demand for ED services exceeds the ability ...
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Efficiency analysis of emergency departments in metropolitan areas
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Publisher and Date:(Elsevier, 2019)The demand in the healthcare industry is increasing exponentially due to aging population of the world and this is leading to a rapid increase in the cost of healthcare. The emergency departments of the hospitals are the frontline of health care systems and play an additional critical role in providing an efficient and high-quality response for patients. The overcrowding at the emergency departments due to growing demand results in a situation where the demand for ED services exceeds the ability ...
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Energy efficient robust scheduling of periodic sensor packets for discrete rate based wireless networked control systems
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Publisher and Date:(Elsevier, 2020)Wireless networked control systems (WNCSs) require the design of a robust scheduling algorithm that meets the stringent timing and reliability requirements of control systems, despite the limited battery resources of sensor nodes and adverse properties of wireless communication for delay and packet errors. In this article, we propose a robust delay and energy constrained scheduling algorithm based on the exploitation of the mostly pre-known periodic data generation nature of sensor nodes in control ...
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Evaluation of the fractal dimension of polyacrylamide during gelation and swelling
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Publisher and Date:(Elsevier, 2021)
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Forecasting electricity demand for Turkey: Modeling periodic variations and demand segregation
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Publisher and Date:(Elsevier, 2017)In deregulated electricity markets the independent system operator (ISO) oversees the power system and manages the supply and demand balancing process. In a typical day the ISO announces the electricity demand forecast for the next day and gives participants an option to prepare offers to meet the demand. In order to have a reliable power system and successful market operation it is crucial to estimate the electricity demand accurately. In this paper we develop an hourly demand forecasting method ...
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Identification of potential inhibitors of human methionine aminopeptidase (type II) for cancer therapy: Structure-based virtual screening, ADMET prediction and molecular dynamics studies
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Publisher and Date:(Elsevier, 2020)Methionine Aminopeptidases MetAPs are divalent-cofactor dependent enzymes that are responsible for the cleavage of the initiator Methionine from the nascent polypeptides. MetAPs are classified into two isoforms: namely, MetAP1 and MetAP2. Several studies have revealed that MetAP2 is upregulated in various cancers, and its inhibition has shown to suppress abnormal or excessive blood vessel formation and tumor growth in model organisms. Clinical studies show that the natural product fumagillin, and ...
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Managing natural gas demand for free consumers under uncertainty and limited storage capacity
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Publisher and Date:(Elsevier, 2020)Demand for energy sources depends on several factors such as population growth, urbanization, industrialization, and climate. Among fundamental energy sources, natural gas is characterized by storage limitations and take-or-pay contracts, which makes it especially critical to forecast the demand accurately for cost management policies. Suppliers of natural gas require take-or-pay contracts to ensure that consumers pay for any unused amount up front; and if the demand exceeds the agreed amount, ...
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A max–min model of random variables in bivariate random sequences
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Publisher and Date:(Elsevier, 2021)We introduce a max–min model to bivariate random sequences and applying bivariate binomial distribution in fourfold scheme derive the distributions of associated order statistics in a new model. Some examples for special cases are presented and applications of the results in reliability analysis and actuarial sciences are discussed.
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Measuring energy intensity in Japan: A new method
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Publisher and Date:(Elsevier, 2017)Energy intensity and energy conservation have been important pillars of energy policies in Japan. Recently the government has introduced new initiatives to enhance energy efficiency and reduce energy intensity. We analyze the energy intensity in Japan for the period 1973-2006 by proposing a new method which takes into account all other inputs used in production and corrects for the bias in the traditional energy intensity measure. We show that the traditional energy intensity measure has serious ...
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Models for relief routing: Equity efficiency and efficacy
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Publisher and Date:(Elsevier, 2011)In humanitarian relief operations vehicle routing and supply allocation decisions are critically important. Similar routing and allocation decisions are studied for commercial settings where efficiency in terms of minimizing cost is the primary objective. Humanitarian relief is complicated by the presence of multiple objectives beyond minimizing cost. Routing and allocation decisions should result in quick and sufficient distribution of relief supplies with a focus on equitable service to all aid ...
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A multidimensional investigation of pretend play and language competence: Concurrent and longitudinal relations in preschoolers
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Publisher and Date:(Elsevier, 2020)Play is an important tool for children's social interactions and cognitive skills. The current study examines the links between pretend play and language in 119 Turkish preschoolers at two time points tested one-year apart (Time 1 M-age = 45.82 months and Time 2 M-age = 57.68 months). Preschoolers' language competence (linguistic complexity and receptive vocabulary) was assessed along with several pretend play measures (telephone task, imaginary pantomime task, pretense score from a free play ...
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Multidirectional Relationship between Energy Resources, Climate Changes and Sustainable Development: Technoeconomic Analysis
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Publisher and Date:(Elsevier, 2020)Global changes in temperature will likely change energy use and electricity production capacity. Considering the relationship between climate change and energy resource use, changes in temperature and the frequency and intensity of extreme events will affect how much energy is produced and consumed. The green economy and green growth are located at the heart of the fight against climate change in creating sustainable development. This paper considers the multidirectional relations between climate ...
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Municipal solid waste management via mathematical modeling: A case study in İstanbul, Turkey
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Publisher and Date:(Elsevier, 2019)The prominence of managing municipal solid waste (MSW) in an efficient and effective manner is increasing from day to day. In this paper, the solid waste management (SWM) system of İstanbul is analyzed by applying the techniques from mathematical programming methodology. In this manner, the solutions of the two optimization problems which aim to minimize the total cost and the environmental effects of SWM, respectively, are presented in this study. Additionally, a sensitivity analysis is performed ...
