Papers by Cem Polat Cetinkaya
Farklı altyapı kategorilerinde yer alan basketbolcuların bazı motorik özellikleri ile şut isabetlerinin yaş ve cinsiyete göre karşılaştırılması
Danisman: PROF. DR. RASIM KALE Yer Bilgisi: Istanbul Gelisim Universitesi / Saglik Bilimleri Enst... more Danisman: PROF. DR. RASIM KALE Yer Bilgisi: Istanbul Gelisim Universitesi / Saglik Bilimleri Enstitusu / Antrenorluk Egitimi Anabilim Dali / Hareket ve Antrenman Bilim Dali Konu: Spor = Sports Dizin: Biyomotorik ozellikler = Biomotoric properties
Meteorological and Agricultural Drought Risk Assessment via Kaplan-Meier Survivability Estimator Supplementary Data
Zenodo (CERN European Organization for Nuclear Research), Dec 19, 2023
Agriculture, Mar 20, 2024
Dry periods and drought are inherent natural occurrences. However, due to the increasing pressure... more Dry periods and drought are inherent natural occurrences. However, due to the increasing pressures of global warming and climate change, these events have become more frequent and severe on a global scale. These phenomena can be traced with various indicators and related indices proposed by various scholars. In general, drought risk assessment is done by modeling these indicators and determining the drought occurrence probabilities. The proposed adaptation introduces the "Kaplan-Meier estimator", a non-parametric statistic traditionally used in medical contexts to estimate survival functions from lifetime data. The study aims to apply this methodology to assess drought risk by treating past droughts as "events" and using drought indicators such as the Standardized Precipitation Index (SPI) and Standardized Precipitation Evapotranspiration Index (SPEI). Mapping these results for a better understanding of the drought risks on larger spatial scales such as a river basin is also within the expected outcomes. The adapted method provides the probability of non-occurrence, with inverted results indicating the likelihood of drought occurrence. As a case study, the method is applied to SPI and SPEI values at different time steps (3, 6, and 12 months) across 27 meteorological stations in the Gediz River Basin, located in Western Turkey-a region anticipated to be profoundly affected by global climate change. The results are represented as the generated drought risk maps and curves, which indicate that (i) drought risks increase as the considered period extends, (ii) drought risks decrease as the utilized indicator timescales increase, (iii) locally plotted drought curves indicate higher drought risks as their initial slope gets steeper. The method used enables the generation of historical evidence based spatially distributed drought risk maps, which expose more vulnerable areas within the river basin.
Evaluating Impact of Land Use and Land Cover Change Under Climate Change on the Lake Marmara System
Water Resources Management, 2022
Evaluating Impact of Land Use and Land Cover Change Under Climate Change on the Lake Marmara System
Water Resources Management
Fen ve mühendislik bilimleri dergisi, Apr 30, 2018
Havzalarda su kalitesi gözlem ağlarının işletilmesinde numune alma ve örnekleme çalışmaları büyük... more Havzalarda su kalitesi gözlem ağlarının işletilmesinde numune alma ve örnekleme çalışmaları büyük bir önem arz etmektedir. Örnekleme çalışmaları esnasında belirlenmiş su kalitesi istasyonlarından numunelerin elde edilmesi ve laboratuvar analizleri için merkeze götürülmesi belirli fiziksel ve ekonomik kısıtlar dahilinde gerçekleştirilmek zorundadır. Örnekleme işleminin aynı gün içinde bitirilmesi ve laboratuvara ulaştırılması diğer taraftan gözlem sıklığını da etkilemektedir. Yapılan çalışmada bu kısıtları gözeterek aylık örnekleme sıklığına sahip bir ağda örnekleme çalışması yapacak ekiplerin en az masraf ile hangi rotaları izlemeleri gerektiği sorusuna cevap aranmıştır. Problem, Gezgin Satıcı Problemine uyarlanarak En Yakın Komşu algoritması ile çözülmeye çalışılmıştır. Ortaya çıkan metodoloji Gediz Havzasında var olan su kalitesi gözlem ağına uygulanmış ve sonuçta örnekleme çalışmalarının yedi gün içinde tamamlanabileceği bir rota tavsiyesi elde edilmiştir.
Sustainability Issues in Water Management in the Context of Water Security
Water Resources of Turkey, 2019
This chapter basically complements Chap. 13 on river basin management in Turkey and elaborates fu... more This chapter basically complements Chap. 13 on river basin management in Turkey and elaborates further on the concepts of sustainability, integrated water resources management (IWRM), and water security. Sustainability and IWRM are long renowned concepts in Turkey, but their integration into developmental issues and water management has been rather slow. The same is true for the fundamental basis of water security although it is also a new concept in the world. In Turkey, the basic difficulty has been to perceive the link between sustainability, water resources, and development. Misconceptions on these linkages and drawbacks related to institutional and legal aspects of water management in the country have slowed down the development of sound policies for decision making in management. Studies on these issues long remained at academic level, and the early institutional responses were rather slow. The chapter discusses the above problems and presents examples of the few studies carried out on sustainability and water security, including the water-food-energy nexus.
Persistent pressures that relate to nonstationary climate variations and land use/cover changes (... more Persistent pressures that relate to nonstationary climate variations and land use/cover changes (LULCC) keep affecting water resources and their associated environmental services with increasing impact trends worldwide. Lake Marmara, located in Gediz River Basin in Western Turkey, is already considered among the environmentally degraded water resources while counted with a priority wetland due to historical habitats and ecosystem functions. The region is remarkably threatened to its extinction under the combined impacts of both climate and LULCC related concerns. While intensive agricultural practices around the region deplete the lake's inflow sources, low levels of the lake water provide breeding ground for various algae types and cause eutrophication and related massive fish population decreases, in a way restricting local communities' access to fundamental ecosystem services for their survivability. The study investigates the effects of LULCC in the example of Lake Marma...
Deu Muhendislik Fakultesi Fen ve Muhendislik, 2019
Öz Su kalitesi gözlem ağlarının tasarımı ve mevcut ağların iyileştirilmesi problemi; gözlem sürek... more Öz Su kalitesi gözlem ağlarının tasarımı ve mevcut ağların iyileştirilmesi problemi; gözlem sürekliliği, ölçüm sıklığı ve gözlem konumlarının seçimi ile ilgili belirsizlikler, diğer yandan ise gözlem amaçlarının zaman içerisinde değişmesi gibi nedenlerden dolayı halen çözümü araştırılan bir problemdir. Bu nedenle gözlem ağı tasarımı ve mevcut gözlem ağlarının iyileştirilmesi konusu çok kriterli değerlendirmeye ihtiyaç duymaktadır ve zaman içinde değişen gözlem amaçlarına göre de var olan sistemin uyumlandırılması gerekliliği vardır. Problemin varolan karmaşık yapısı nedeniyle halihazırda kesin bir yöntem bulunmamaktadır. Çok kriterli optimizasyon ve karar verme yöntemleri ile yapılan önceki çalışmalarda özellikle kriterlere atanan önem ve ağırlık katsayılarının seçimi gözlem ağı ile ilgili verilen kararları doğrudan etkilemektedir. Sunulan çalışma, ağırlık katsayılarının tayinini gerektirmeyen bir çok kriterli karar verme yöntemi olan Referans Noktası Yöntemini (RNY) esas alarak, su kalitesi gözlem ağı performansını irdelemeyi amaçlamaktadır. Yöntem Gediz havzasına uygulanarak, 1985-2000 yılları arasında gözlemlenen veriler ile mevcut su kalitesi gözlem ağı amaçlarına göre istasyon bazında performans belirlenmiş ve çıkan sonuçlar irdelenmiştir. Referans Noktası Yöntemi gözlem ağı performansı değerlendirmesinde kolaylıkla kullanılabilecek bir yöntem olarak değerlendirilmiştir.
Servizi di consulenza per l’irrigazione L’esperienza del progetto SIRIUS
Water scarcity is a growing concern for global agriculture, many irrigated areas have experienced... more Water scarcity is a growing concern for global agriculture, many irrigated areas have experienced in recent years a reduction in water availability due both to its decrease and an increase in demand for water for domestic and industrial use. Future scenarios, due to climate change could intensify the problems of water scarcity and irrigation requirements in the regions characterized by high drought , while areas not traditionally affected by water scarcity could raise the question of a revision of the management policies adopted so far (IPCC , 2007). An accurate assessment of requests for water resource for irrigation (as well as for other uses) is therefore a prerequisite for a more rational management of water (Maton, L., et al, 2005) and an overview of the large-scale use water may contribute to the development of appropriate policies and management strategies. At EU level so far the main objectives of the policy on protection of water resources and protection from water stress, ...
dsi.gov.tr
The operational objective of DSI's current water quality monitoring networks is "to preserve and ... more The operational objective of DSI's current water quality monitoring networks is "to preserve and improve the surface water quality". In the scope of this objective, the monitoring goals of the nationwide water quality network may be summarized as to assess the current water quality conditions and to detect the temporal changes (trends) in quality. Therefore, the prediction of the mean value and trends at a specific level of statistical significance through systematic approaches is very important in order to define the monitoring goals in statistical terms. The objectives of this study are to assess the necessary sampling interval to predict long-term average value of water quality variables by the methodology proposed by Sanders and Adrian (1978), and to decide upon the required sampling interval to detect the ongoing trends in water quality at a specific statistical significance level through the method applied by Lettenmaier (1976). In this study, the results obtained within the project on "The Assessment of Efficiency in DSI's Water Quality Monitoring Networks-Monitoring Network Optimization-II" (TUBITAK-YDABAG-100Y102) are discussed and evaluated. The project mentioned is run by DEU Civil Engineering Department, Hydraulics Division with collaboration of DSI General Directorate Domestic and Wastewater Division.
Assessment of Information related to Floods
Proceedings of the Eighth International Conference on Civil and Structural Engineering Computing
ABSTRACT The study presented demonstrates the use of the entropy concept, as defined in informati... more ABSTRACT The study presented demonstrates the use of the entropy concept, as defined in information theory, to assess the regional uncertainty and indirectly the regional information available about floods. The method is used to describe the total uncertainty related to floods in a basin, together with the joint information provided by observed data of existing streamflow gages. The contribution of each gage to this total information is assessed eventually to arrive at a better combination of stations in transferring flood information from one space point to another. This is realized by a priority listing of stations in order of their contribution to the decrease in regional uncertainty. The application of the method is demonstrated in the case of a Turkish river basin, where coping with floods is a major problem. The strengths and shortcomings of the method are discussed, with recommendations for future research on the application of the entropy principle in evaluating regional transfer of information about floods.
Cogent Food & Agriculture
Irrigated agriculture is a key activity for the long-term survival of humanenvironmental systems ... more Irrigated agriculture is a key activity for the long-term survival of humanenvironmental systems and the assessment of agricultural sustainability has been gaining increasing relevance. In spite of several proposals developed, there is not a holistic approach that can be generally applied to assess sustainability of irrigated agricultural areas. In this paper we present a framework and associated indicators for the assessment of sustainability of irrigated agricultural systems in different contexts and locations. The framework covers four main sustainability dimensions: environmental integrity, economic resilience and profitability, social wellbeing and good governance. This approach was tested in 10 agricultural areas in eight different countries that represent a wide variety of situations in terms of agricultural development, environmental conditions, socioeconomic settings and political contexts, but that share the fact that water use is a critical aspect for agricultural development. The obtained results illustrate the usefulness of the proposed framework to obtain a holistic picture of sustainability in irrigated agriculture areas, even in situations
International Conference on Informatics for Environmental Protection, 2004
Allocation of sampling sites is the initial and the most crucial step of the water quality monito... more Allocation of sampling sites is the initial and the most crucial step of the water quality monitoring network design and redesign process. Several different approaches have been used within the last 20-30 years in the selection of sampling sites. As yet, there are no standard design procedures to accomplish such a network. However, there are some scientific methods which may help to minimize the subjective aspects of design. This paper examines the application of an optimization method that can be used to assess an existing water quality monitoring for information transfer between its sampling sites. The method uses dynamic programming to evaluate the reduction of the number of sampling sites in a basin with respect to different monitoring objectives. The methodology is demonstrated in the case of the Gediz River basin in Turkey.
Cogent Food & Agriculture
Irrigated agriculture is a key activity for the long-term survival of humanenvironmental systems ... more Irrigated agriculture is a key activity for the long-term survival of humanenvironmental systems and the assessment of agricultural sustainability has been gaining increasing relevance. In spite of several proposals developed, there is not a holistic approach that can be generally applied to assess sustainability of irrigated agricultural areas. In this paper we present a framework and associated indicators for the assessment of sustainability of irrigated agricultural systems in different contexts and locations. The framework covers four main sustainability dimensions: environmental integrity, economic resilience and profitability, social wellbeing and good governance. This approach was tested in 10 agricultural areas in eight different countries that represent a wide variety of situations in terms of agricultural development, environmental conditions, socioeconomic settings and political contexts, but that share the fact that water use is a critical aspect for agricultural development. The obtained results illustrate the usefulness of the proposed framework to obtain a holistic picture of sustainability in irrigated agriculture areas, even in situations
Deu Muhendislik Fakultesi Fen ve Muhendislik, 2018
Gediz Havzası'nda yıllar içinde yaşanan farklı şiddetlerdeki kuraklıklar, havzanın orta ve aşağı ... more Gediz Havzası'nda yıllar içinde yaşanan farklı şiddetlerdeki kuraklıklar, havzanın orta ve aşağı kısımlarında bulunan yaklaşık 110000 hektar sulama alanında sürdürülen tarımsal faaliyetleri etkilemiştir. Yapılan çalışmada, 1995-2012 yılları arasında Gediz Havzası'nda tarımsal sulama yapılan alanların büyüklüğünde, ürün alım fiyatlarında, bitki deseninde ve sulama suyuna olan ihtiyaçta yaşanan değişimler tespit edilmiş ve aralarındaki ilişkiler doğrusal regresyon yöntemiyle irdelenmiştir. Bitki deseni değişimlerinde bir önceki yılın ürün fiyatları ile doğrudan bir ilişki bulunduğu, çiftçinin buna göre davrandığı ve sonucunda havzadaki hâkim ürün önceliğinin değiştiği belirlenmiştir. Ayrıca ürün desenindeki değişim sonucunda aylık sulama suyu tahsis planlarının etkileneceği, pik su ihtiyacı değerlerinin ve tarihlerinin değişeceği vurgulanmıştır.
Afyon Kocatepe University Journal of Sciences and Engineering, 2018
Anahtar kelimeler Su Kalitesi Gözlem Ağı; Su Kalitesi Örnekleme; Optimizasyon; Gezgin Satıcı Prob... more Anahtar kelimeler Su Kalitesi Gözlem Ağı; Su Kalitesi Örnekleme; Optimizasyon; Gezgin Satıcı Problemi, En Yakın Komşu Algoritması Özet Havzalarda su kalitesi gözlem ağlarının işletilmesinde numune alma ve örnekleme çalışmaları büyük bir önem arz etmektedir. Örnekleme çalışmaları esnasında belirlenmiş su kalitesi istasyonlarından numunelerin elde edilmesi ve laboratuvar analizleri için merkeze götürülmesi belirli fiziksel ve ekonomik kısıtlar dahilinde gerçekleştirilmek zorundadır. Örnekleme işleminin aynı gün içinde bitirilmesi ve laboratuvara ulaştırılması diğer taraftan gözlem sıklığını da etkilemektedir. Yapılan çalışmada bu kısıtları gözeterek aylık örnekleme sıklığına sahip bir ağda örnekleme çalışması yapacak ekiplerin en az masraf ile hangi rotaları izlemeleri gerektiği sorusuna cevap aranmıştır. Problem, Gezgin Satıcı Problemine uyarlanarak En Yakın Komşu algoritması ile çözülmeye çalışılmıştır. Ortaya çıkan metodoloji Gediz Havzasında var olan su kalitesi gözlem ağına uygul...
Allocation of sampling sites is the initial and the most crucial step of the water quality monito... more Allocation of sampling sites is the initial and the most crucial step of the water quality monitoring network design and redesign process. Several different approaches have been used within the last 20-30 years in the selection of sampling sites. As yet, there are no standard design procedures to accomplish such a network. However, there are some scientific methods which may help to minimize the subjective aspects of design. This paper examines the application of an optimization method that can be used to assess an existing water quality monitoring for information transfer between its sampling sites. The method uses dynamic programming to evaluate the reduction of the number of sampling sites in a basin with respect to different monitoring objectives. The methodology is demonstrated in the case of the Gediz River basin in Turkey.
Due to several socio-economic reasons, crop patterns of a basin may vary over the years. The prim... more Due to several socio-economic reasons, crop patterns of a basin may vary over the years. The primary reason generally tends to be on the economic aspect. Such a change has took place in Gediz Basin, Turkey; in between the years 1997-2012, a dramatic transition occurred in crop pattern due to economic pressures. Agricultural communities of Gediz Basin have shifted their main yearly crop from cotton to maize because of forcing benefit/cost ratios. Due to the total and monthly differences between two crops’ water requirements, irrigation water demand has also altered throughout the years. The main reservoir Demirkopru has the primary purpose of providing water during the summer season for the lower basin embodying around 110 000 ha of irrigated area. The change in crop patterns has put the effectiveness of the produced energy now in question. Although the power generation contributes negligible amounts versus agricultural production to the gross income in the basin, its cost-effectiven...
Entropy
This study attempts to extend the prevailing definition of informational entropy, where entropy r... more This study attempts to extend the prevailing definition of informational entropy, where entropy relates to the amount of reduction of uncertainty or, indirectly, to the amount of information gained through measurements of a random variable. The approach adopted herein describes informational entropy not as an absolute measure of information, but as a measure of the variation of information. This makes it possible to obtain a single value for informational entropy, instead of several values that vary with the selection of the discretizing interval, when discrete probabilities of hydrological events are estimated through relative class frequencies and discretizing intervals. Furthermore, the present work introduces confidence limits for the informational entropy function, which facilitates a comparison between the uncertainties of various hydrological processes with different scales of magnitude and different probability structures. The work addresses hydrologists and environmental engineers more than it does mathematicians and statisticians. In particular, it is intended to help solve information-related problems in hydrological monitoring design and assessment. This paper first considers the selection of probability distributions of best fit to hydrological data, using generated synthetic time series. Next, it attempts to assess hydrometric monitoring duration in a netwrok, this time using observed runoff data series. In both applications, it focuses, basically, on the theoretical background for the extended definition of informational entropy. The methodology is shown to give valid results in each case.
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Papers by Cem Polat Cetinkaya