110 research outputs found
Comparing clusterings and numbers of clusters by aggregation of calibrated clustering validity indexes
No full textAkhanli, Serhat Emre/0000-0001-7173-3277WOS: 000543319300001A key issue in cluster analysis is the choice of an appropriate clustering method and the determination of the best number of clusters. Different clusterings are optimal on the same data set according to different criteria, and the choice of such criteria depends on the context and aim of clustering. Therefore, researchers need to consider what data analytic characteristics the clusters they are aiming at are supposed to have, among others within-cluster homogeneity, between-clusters separation, and stability. Here, a set of internal clustering validity indexes measuring different aspects of clustering quality is proposed, including some indexes from the literature. Users can choose the indexes that are relevant in the application at hand. In order to measure the overall quality of a clustering (for comparing clusterings from different methods and/or different numbers of clusters), the index values are calibrated for aggregation. Calibration is relative to a set of random clusterings on the same data. Two specific aggregated indexes are proposed and compared with existing indexes on simulated and real data.EPSRCEngineering & Physical Sciences Research Council (EPSRC) [EP/K033972/1]The work of the second author was supported by EPSRC grant EP/K033972/1
Reflections on methodology for assessing campus sustainability from a Turkish perspective
No full textAim: The author provides a critical reflection of the questionnaire discussed at the workshop “Methodology for assessing the campus sustainability from the perspective of multi-level antifragility” held on Friday 13 May at the WSB University in Wrocław. The author reflects from the background of his experience in Turkey. Design / Research methods: The author provides his own reflections and opinions, based on the discussions at the workshop. Conclusions / findings: It is very difficult to create a set of indicators making campus sustainability internationally comparable, as well as finding proper sources of information. A starting point in creating such indicators may be mistakes threatening organizational viability and external sustainability Originality / value of the article: The article provides critical feedback on an innovative approach towards research on campus sustainability. </jats:p
Measuring Nature of Science Views of Middle School Students
No full textDeveloping scientific literacy for all students is the most often stated purpose of contemporary science education. Nature of science (NOS) is seen as an important component of scientific literacy. There are various perceptions of NOS in the science education community and NOS itself is an ever-changing construct. This makes it challenging to develop instruments for measuring understanding of NOS at different levels. Many instruments have been developed and are being developed to assess NOS learning, which indicates the importance attributed to this subject. In this study, we developed a multiple-choice test to measure NOS understanding of middle school students. The instrument was applied to 1397 middle school students. The 24 item multiple-choice test had KR-20 reliability coefficient of 0.74. A 12 item multiple-choice test created as a subset of the 24 items of the original test. This test was easier and had higher discrimination, which can provide useful measurement data about students' understanding of NOS for diagnostic or formative purposes
Classification of juvenile myoclonic epilepsy data acquired through scanning electromyography with machine learning algorithms
No full textOsman, Onur (Arel Author), Özekes, Serhat (Arel Author)In this paper, classification of Juvenile Myoclonic Epilepsy (JME) patients and healthy volunteers included into Normal Control (NC) groups was established using Feed-Forward Neural Networks (NN), Support Vector Machines (SVM), Decision Trees (DT), and Na < ve Bayes (NB) methods by utilizing the data obtained through the scanning EMG method used in a clinical study. An experimental setup was built for this purpose. 105 motor units were measured. 44 of them belonged to JME group consisting of 9 patients and 61 of them belonged to NC group comprising ten healthy volunteers. k-fold cross validation was applied to train and test the models. ROC curves were drawn for k values of 4, 6, 8 and 10. 100% of detection sensitivity was obtained for DT, NN, and NB classification methods. The lowest FP number, which was obtained by NN, was 5
Political Endowments and Electricity Market Regulation in Turkey: An Institutional Analysis
No full textTurkey has been going through a liberalization process in its electricity market over the last decade. So far, the regulatory content of the market reforms has been in the center of attention in the literature, to the negligence of regulatory governance. However, recent studies, which applied the theoretical insights of new institutional economics to utilities regulation, have demonstrated that political endowments of the country draw the boundaries to which extent such regulatory content can be effectively implemented. In line with these studies, this paper adopts an institutional approach and attempts to identify the political endowments of Turkey in order to further analyze whether the market reforms succeeded in bringing about sufficient checks to cure the institutional problems. In other words, the paper takes a picture of the overall regulatory arena. The results show that the current regulatory structure, especially government-regulator relations, fails to meet good regulatory governance criteria. The paper also provides some policy suggestions.electricity regulation; regulatory governance; institutions
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Session B6: Hydraulic Design of an Innovative Baffle-Brush Type Fish Pass
No full textPresenting Author Bio: Dr. Serhat Kucukali completed his MSc and PhD degrees in Hyraulic Engineering at the Istanbul Technical University. He was a Post-doc fellow in the Civil Engineering Department of University of Queensland in Australia. He has published more than 40 research papers and his work was cited over 200 times. He has been conducting research on hydropower, environmental hydraulics, and sustainability. He developed an Environmental Risk Index for Small Hydropower Plants.Abstract: The flow characteristics (depth, velocity, energy dissipation) of a new baffle-brush type fish pass were investigated experimentally in a 2 m wide rectangular flume which has a bed slope of 4% for discharges ranging between100-550 L/s. In all experiments quasi-uniform and subcritical flow conditions, Froude number ranging between 0.17-0.23, were observed. The Darcy-Weisbach friction factor was negatively correlated with the relative submergence of the baffle. The turbulence intensities were ranged between %38-79 in the baffle zone and %13-31 in the brush zone. The hydraulic test results showed that this type of fish pass can produce adequate flow depth and favorable local flow velocities for the design discharge of 0.2 m2/s (relative submergence of brushes=1.03). The hydraulic test results reveal that baffle-brush fish pass fulfill the requirements of an efficient fish passage by providing tranquil flows and sufficient flow depths for different fish species. Consequently, the following design procedure can be used for the proposed baffle-brush fish pass: (i) required flow depth can be specified for the target fish species, (ii) the friction factor can be estimated based on the relative submergence of baffle, and (iii) for the given bed slope, average flow velocity and discharge values can be computed from Darcy-Weisbach formula. The main advantage of the proposed hydraulic design is that we can scale-up all the parts of this type in order to adjust it to almost any demand based on the model test results
Socially Responsible Mutual Funds and Their Performance Characteristics
No full textSocially responsible or ethical investing has been developed dramatically since last three decades. Socially responsible or ethical investing can be defined as a set of approaches which include social or ethical goals or constraints as well as more conventional financial criteria in decisions over whether to acquire, hold or dispose of a particular investment. Socially responsible investing is the reflection of ethical values in financial markets. Socially responsible investing is a new topic in Turkey and it is an important one on which is needed to be put emphasis. This paper reviews concepts of socially responsible investing and socially responsible mutual fund which is mostly applied special approach of socially responsible investing. Furthermore, the performance of socially mutual funds compared to other mutual funds which are constituted based on conventional financial criteria is examined in this paper. In addition, the application of socially responsible mutual funds in Turkey is examined. We conclude with some suggestions about how to improve the applications of socially responsible investing in Turkey
A simulation study for determination of refractive index dispersion of dielectric film from reflectance spectrum by using Paul wavelet
No full text32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYIn this work, the Continuous Wavelet Transform (CWT) with Paul wavelet was improved as a tool for determination of refractive index dispersion of dielectric film by using the reflectance spectrum of the film The reflectance spectrum was generated theoretically in the range of 0.8333 - 3.3333 mu m wavenumber and it was analyzed with presented method. Obtained refractive index determined from various resolution of Paul wavelet were compared with the input values, and the importance of the tunable resolution with Paul wavelet was discussed briefly. The noise immunity and uncertainty of the method was also studied.Turkish Phys So
An improved method for determination of refractive index of absorbing films: A simulation study
No full text32nd International Physics Congress of Turkish-Physical-Society (TPS) -- SEP 06-09, 2016 -- Bodrum, TURKEYIn this work an improved version of the method presented by Gandhi was presented for determination of refractive index of absorbing films. In this method local maxima of consecutive interference order in transmittance spectrum are used. The method is based on the minimizing procedure leading to the determination of interference order accurately by using reasonable Cauchy parameters. It was tested on theoretically generated transmittance spectrum of absorbing film and the details of the minimization procedure were discussed.Turkish Phys So
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