Mühendislik Fakültesi / Faculty of Engineering
Permanent URI for this collectionhttps://hdl.handle.net/11727/1401
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Item An Exergy-Based Algorithm for Optimizing CHP Systems in Health Facilities(2014) Kilkis, Birol I.Health facilities have diverse thermal and electrical loads with challenging profiles and non-coincident peaks. This paper lays the basic optimization algorithm, with two objectives, namely minimizing CO2 emissions and reducing the pay-back period of the investment. The algorithm is based on the Rational Exergy Management Model and searches the optimum CHP capacity with the objective of maximum exergy efficiency. The algorithm also factors in the negative effect of tree cutting on CO2 sequestration potential, which often occurs in the construction of very large new hospitals. Four building scenarios were analyzed, one which is a business as usual type of health facility building and the fourth one is a near net-zero energy and exergy building. Results show that the optimization search may substantially increase the exergy efficiency, fuel savings, and reduce CO2 emission by up to 50%.Item Video Scene Classification Using Spatıal Pyramid Based Features(2014) Sert, Mustafa; Ergun, Hilal; https://orcid.org/0000-0002-7056-4245; AAB-8673-2019Recognition of video scenes is a challenging problem due to the unconstrained structure of the video content. Here, we propose a spatial pyramid based method for the recognition of video scenes and explore the effect of parameter optimization to the recognition accuracy. In the experiments different sampling methods, dictionary sizes, kernel methods, and pyramid levels are examined. Support Vector Machine (SVM) is employed for classification due to the success in pattern recognition applications. Our experiments show that, the size of dictionary and proper pyramid levels in feature representation drastically enhance the recognition accuracy.Item Dual Band Antenna Design for Long Term Evolution Applications(2014) Degerliyurt, Dilara; Isik, Gulsum; Can, Sultan; Yilmaz, A. EgemenIn this study antenna geometries for use in Long Term Evolution (LTE) applications are presented. The proposed antennas are designed in a shape of U, they are fed by coax, and such geometry achieves dual frequency operation. All the proposed geometries are simulated via CST and Ansoft HFSS software, and the results are assessed as regards return loss, operating frequency, bandwidth, and standing wave ratio. In addition, the literature review is also presented for LTE systems and for the antennas usually preferred in LTE systems.Item Feasıbility of Heart Rate Variability Analysis With Heart Sounds(2014) Yildiz, Metin; Turkoglu, Zeynep; https://orcid.org/0000-0002-2554-6953; JJF-5070-2023Heart rate variability (HRV) analysis, which is providing information about the autonomic nervous system with non-invasive method, performed with using digitized electrocardiogram records. In this study, whether HRV analysis can be done from heart sounds (which are recorded with electronic stethoscopes) has been investigated. For this purpose, an algorithm has been developed for detecting the consecutive heart time period from simultaneously recorded heart sounds and ECG. Some standard HRV parameters are calculated and compared from the HRV derived from ECG and heart sound signals. The experimental results show that, both HRV parameters derived from the heart sounds while the resting position and the ECG are very close. In conclusion, they can be used in HRV analysis.Item Calibration Transfer Between E-Noses(2014) Guney, Selda; Fernandez, Luis; Marco, Santiago; https://orcid.org/0000-0002-0573-1326; AAC-7404-2020Electronic nose is an instrument which is composed of gas sensor array and pattern recognition unit. It is generally used for classifying, identifying or quantifying the odors or volatile organic components for these commonly used devices, calibration transfer is an important issue because of differences in each instrument, sensor drift, changes in environmental conditions or background changes. Calibration transfer is a transfer of model between different instruments which have different conditions. In this study, calibration transfer is applied to the e-noses which have different temperature conditions. Also the results of the direct standardization, piecewise direct standardization and orthogonal signal correction which are different calibration methods were compared. The results of the piecewise direct standardization method are more successful than the other methods for the dataset which is used in this study.Item Estimating Land Cover Type And Proportıon Of Vegetation Using Remote Sensing(2014) Erol, Cemil Berin; Tanyer, Suleyman Gokhun; https://orcid.org/0000-0001-9506-2391; I-5023-2013Estimation of the land cover type and proportion of vegetation using NASA's EOS/MODIS data is verified as a case study for Turkey where 7 locations were selected. The correlation between the NDVI/EVI data is analyzed. EVI is shown to be slightly more accurate than NDVI. Land cover types are determined for these 7 locations, and similar to other locations, Istanbul and Samsun are found to perfectly match the 'forest type' Izmir is found to be different from the currently available land cover types which are assumed to be due to its mixed canopy structure. Annual and monthly average measurements in various bands are analyzed and expected correlation with the number of days of precipitation is observed.Item Randomness Tests For The Method Of Unıform Sampling Quasi-Random Number Generator (MUS-QRNG)(2014) Atalay, Kumru Didem; Tanyer, Suleyman Gokhun; https://orcid.org/0000-0001-9506-2391; I-5023-2013Random number generation is still an important research field in many scientific applications today. Cryptography, Monte Carlo simulations and commertial applications all rely on reference random data. Randomness tests and basic statistics share the same history. Randomness can be summarized as the unpredictability of future samples of a random number generator even in the presence of known all past values. Various randomness tests are developed and due to their individual contributions, usually a battery of tests are applied to verify a random number generator. In signal processing however, the error of a specific observed sample set to a given distribution could be much more important when it is used as the input for a system model. Recently, this distance of finite samples set to a given distribution is studied and a quantitative measure for quality is proposed Multi run computations like Monte Carlo simulations, often rely on accurate statistical data for high repetibility. Otherwise when the data is not accurate, the results could often rely on the source of random data generator. Many runs are often required to gain a confidence in the presence of those variances. In this work, recently proposed quasi-random number generator utilizing method of uniform sampling NUS) is tested using standard goodness-of-fitness tests. MUS-QRNG numbers are shown to have exact statistics and also their randomness test results are observed to be similar to well known reference generator of Matlab. MUS-QRNG is proposed for high quality random data generation.Item An Aloha Based Throughput Analysis For Cognitive Radio Applications in Tv Bands(2014) Tuncer, A. TurgutSince existing spectrum is limited and could not efficiently be used, new ways to solve this problem are brought forth. The unused bands currently allocated to TV broadcasting services can be opportunistically reassigned to support broadband networking services while continuing to provide broadcast TV The fragmented and unused TV channels have considerable amount of bandwidth potential and long transmission ranges. This paper considers an OFDM based wireless communications system using TV bands. To make a good use of spectral resources, two OFDM paradigms, ie., Fixed Carrier Spacing (FCS) and Fixed Carrier Number (FCN), have been investigated deeply for Aloha-Medium Access Control protocol in TV white spaces.Item Content-Based Retrieval of Microarray Experiments(2016) Ogul, Hasan