2018 Cilt 23 Sayı 1

Permanent URI for this collectionhttps://hdl.handle.net/11452/12169

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Now showing 1 - 9 of 9

Co-occurrence weight selection for word embeddings to enhance test performance
(Uludağ Üniversitesi, 2018-02-07) Koç, Aykut; Yücesoy, Veysel
This study revisits the problem of maximizing the performance of mathematical word representations for a given task. It is aimed to improve performance in analogy and similarity tasks by suggesting innovative weights instead of the counting weights used conventionally in counting-based methods of generating word representations (adding the statistics of word co-occurrences to the account). The language of study was selected as Turkish. The root structures of Turkish words were managed during the compilation of corpus such that each word having a suffix was considered as a new word. The performance of the proposed co-occurrence weights are analyzed with respect to the varying parameter and the results are presented within the paper.
Design, construction and results of a low energy DC ion accelerator
(Uludağ Üniversitesi, 2018-03-06) Karadeniz, Hande
The main purpose of in this study is described to optimal design and construction of low energy DC ion accelerator with energy up to 100 keV. Initial measurements obtained are given. This small accelerator includes an ICP type ion source, an accelerator tube with 7 electrodes, two quadrupol magnet for focusing, one dipole magnet for bending and a faraday cup at the end of beam line to measure ion current. The existing technology was used to make the major components. Simulation results for ion source, DC accelerator tube and magnets are presented performed with SIMION, WINAGILE, GPT codes.
Four-wave mixing impacts on the uplink performance of dense wavelength division multiplexing gigabit passive optical networks
(Uludağ Üniversitesi, 2018-03-07) Saleh, Abbas Yuldurum Saleh; Karlık, Sait Eser; Mühendislik Fakültesi; Elektrik Elektronik Mühendisliği Bölümü
Four-wave mixing (FWM) is an important nonlinear effect severely limiting the performance of optical fiber networks. In this paper, FWM impact on the uplink performance of dense wavelength division multiplexing gigabit passive optical networks (DWDM-GPONs) using standard single mode fibers (SSMFs) has been analyzed. Simulations have been carried out on the center uplink channels of 7-, 15-, 29- and 35-channel DWDM-GPON systems that have 12.5 GHz, 25 GHz, 50 GHz and 100 GHz channel spacing values. Signal-to-crosstalk ratio (SXR) variations occurring due to FWM impacts have been considered in evaluating the uplink performance. Simulation results exhibit worst-case values under FWM impacts and therefore are important in giving clues about choosing system parameters satisfying a minimum 23 dB SXR, which is an appropriate value for current GPON applications showing system reliability under FWM impacts.
Monthly natural gas consumption’s modelling and its trend analysis for Yozgat in Turkey
(Uludağ Üniversitesi, 2017-12-31) Ay, Murat
In this study, an energy consumption modelling for long term (December 2006- March 2016) forecasting of monthly natural gas consumption in households and industry area for Yozgat city, Turkey was presented. In this context, it can be said that this paper has two purposes. One of them is the application and accuracy of the artificial neural networks. Estimate performances are compared with each other, and the estimates of the optimal models are evaluated with the monthly recorded natural gas consumption according to root mean square error, mean absolute error, and correlation coefficient. The other purpose of the study is to analysis trend of monthly natural gas consumption of Yozgat by using Mann-Kendall and a new method recently proposed by Şen. The results showed that the artificial neural networks gave satisfactory results in estimating monthly natural gas consumption. In the trend analysis, it was seen that both Mann-Kendall and Şen trend tests gave statistically significant increasing trend at 95% confidence level for monthly natural gas consumption of Yozgat.
Motion optimization of a 6 axes robot manipulator used for material handling purposes via dynamic programming
(Uludağ Üniversitesi, 2018-03-02) Gören, Aytaç; Çakır, Umut
Due to the increasing cost of energy besides the environmental concerns, energy consumption is one of the hot topic in today’s world. In this context, companies are searching for the ways to reduce their energy consumptions and their Carbon footprint. For a manufacturing company, one method to accomplish these is to increase their process efficiency. In this research, a production cell which contains a robot manipulator used for material handling purposes is tried to be modeled in computer environment, using dynamic programming over the computer model, system parameters increasing production capacity in addition to reducing the energy consumption and improvements depending on these are presented.
New method to compare indoor and outdoor temperature coefficients of photovoltaic modules
(Uludağ Üniversitesi, 2017-11-15) Şentürk, Ali; Eke, Rüştü
In this study, a new method is presented to compare the indoor and outdoor temperature coefficients of photovoltaic module. Precise input of temperature coefficients introduced in the simulation is very essential to obtain accurate results about the actual performance of photovoltaic module/array. Thus, it is important to specify which type (indoor or outdoor) of the temperature coefficient is more accurate in simulating the actual performance. The short circuit current, the open circuit voltage, the output peak power and produced energy are considered as actual performance indexes. New method proposed in this study, simulates the actual performance for both indoor and outdoor temperature coefficients and compares with actual performance measured at field to decide which type of temperature coefficient is more accurate.
Optimization of struvite precipitation for landfill leachate treatment
(Uludağ Üniversitesi, 2018-02-19) Doğan, Selim; Aygün, Ahmet; Argun, Mehmet Emin; Esmeray, Ertuğrul
Sanitary landfill is the most preferred municipal solid waste disposal method. The production of highly polluted leachate is a major disadvantage of sanitary landfills. In this study, optimization of struvite precipitation to remove ammonium from landfill leachate was conducted by using Response Surface Methodology and central composite design. Optimum struvite precipitation conditions were determined based upon 11 runs performed in central composite design. A second-order polynomial functional model was fitted well to the results. The statistical analysis showed that two independent variables which are molar rates of Mg/N and N/P had significant effects on the ammonium removal efficiency. Maximum ammonium removal efficiency was 99.8% at a molar rate of 1.20 for Mg/N and 1.27 for N/P for a constant 9.2 pH value. The obtained results revealed that struvite used as pre-treatment in anaerobic process can be modelled by using response surface methodology. And also, response surface methodology can be used to optimize required ammonium removal efficiency for lower Mg/N and N/P molar ratio which affects the performance of pre-treatment method that designed for an anaerobic process having 300:5:1 ratio for COD/N/P.
Parametric investigation of harnessed power of two tandem cylinders in flow induced vibration
(Uludağ Üniversitesi, 2018-04-05) Dobrucalı, Erinç
In transverse flow, cylinders respond in FIV (Flow Induced Vibrations); particularly VIV (Vortex Induced Vibrations) and galloping. Typically, in the galloping region, the hydrokinetic power converted to mechanical in the oscillators increases with increasing flow velocity and Reynolds number. Flow Induced Vibrations (FIVs) of two tandem, rigid and circular cylinder with end-springs are studied for 30,000
Scaling analysis and self-similarity of onedimensional transport process
(Uludağ Üniversitesi, 2018-03-19) Ercan, Ali
Convection-diffusion equation has been widely used to model a variety of flow and transport processes in earth sciences, including spread of pollutants in rivers, dispersion of dissolved material in estuaries and coastal waters, flow and transport in porous media, and transport of pollutants in the atmosphere. In this study, the conditions under which one-dimensional convection-diffusion equation becomes self-similar are investigated by utilizing one-parameter Lie group of point scaling transformations. By the numerical simulations, it is shown that the one-dimensional point source transport process in an original domain can be self-similar with that of a scaled domain. In fact, by changing the scaling parameter or the scaling exponents of the length dimension, one can obtain several different down-scaled or up-scaled self-similar domains. The derived scaling relations obtained by the Lie group scaling approach may provide additional understanding of transport phenomena at different space and time scales and may provide additional flexibility in setting up physical models in which one dimensional transport is significant.

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