WoS İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/394

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Now showing 1 - 5 of 5
  • Article
    Fluctuations in the European Housing Market: Forecasting the House Price Index Change with Time-Series Models
    (Gazi Univ, 2026-03-15) Soylemez, Ismet; Nalici, Mehmet Eren; Unlu, Ramazan
    This study presents a comparative analysis of a time series models for forecasting changes in the Housing Price Index (HPI) in 27 European countries. Accurate HPI forecasting is essential for the development of effective policies and investment strategies. The study uses quarterly data from Q4 2013 to Q3 2024. Methodologically, the stationarity of the data is tested using the Dickey-Fuller test and differencing is applied to non-stationary series. The ARIMA, Holt Linear Trend, Additive Damped Trend and Exponential Smoothing models are evaluated based on the lowest mean squared error (MSE) value for each country. The findings confirmed the heterogeneous structure of the European housing market, showing that no single model is suitable for all countries. The ARIMA model provided the most accurate results for nine countries, while the Holt Linear Trend and Additive Damped Trend models performed best in seven countries each. Forecasts for the period 2025-2026 are generated based on these results. This study highlights the importance of adopting country-specific and adaptable forecasting approaches to accommodate the varying dynamics of European housing markets.
  • Article
    Loss Calculation Technique With Randomize Load Curves
    (Gazi Univ, 2017) Onen, Ahmet
    Calculating feeder losses accurately is an important part of evaluating designs for electric power distribution systems. Historically, these losses have been calculated one of three ways: (1) using a peak load calculation and the load factor method, (2) using customer class statistics normalized for a month, season, or year, or (3) using customer class statistics together with feeder measurements to reflect the variation in load every hour of the year. The first two methods require far less data but provide far less accuracy than the third method. In this paper, the authors present a method of calculating losses that achieves better accuracy than the first two methods without the large data requirements of the third method.
  • Article
    Citation - WoS: 7
    Conceptual Research of Movement in Kinetic Architecture
    (Gazi Univ, 2018) Ilerisoy, Zeynep Yesim; Pekdemir Basegmez, Merve
    In this study, the place of movement concept in architectural design is investigated; the possibilities provided to the user by evaluating the varying potentials in architectural design have been discussed as a hypothesis. In this direction, movement concept in kinetic structures applied from the 20th century to today are examined. The paper depends on a qualitative methodology, which is a non-numerical method that depends on constructed cases in order to support research hypothesis. Relations, differences and conceptual partnerships between cases have been revealed by investigating the application points of movement and user participation in the design of these structures that is fast-spreading particularly. From the studied examples, it is determined that the surface movement is preferred, when the movement point is taken into consideration the facades are primarily used, and the most common movement type is the sliding movement. Afterwards, it has been revealed that the different physical properties of the movement and the possibilities that are provided change independently of each other. Even in many cases the movement is preferred due to multiple purposes. The most common purpose is adapting to environmental conditions. As a result, this study, which aims to strengthen the perception of architects, will set an example for the development of kinetic architecture.
  • Article
    Citation - WoS: 10
    Self-Healing Performance of Biogranule Containing Microbial Self-Healing Concrete Under Intermittent Wet/Dry Cycles
    (Gazi Univ, 2021) Ersan, Yusuf Cagatay
    Development of self-sensing and self-healing concrete is essential to minimize the labour-intensive monitoring and repair activities conducted for the maintenance of concrete structures. A type of self-healing concrete can be achieved by using microbial agents that induce calcium carbonate precipitation inside a concrete crack. Recently, biogranules consist of nitrate reducing microorganisms were presented as a new generation microbial healing agent and biogranule containing specimens revealed decent healing performance under completely submerged conditions. However, their performance under intermittent wetting conditions, a common case for various concrete structures, remains unknown. This study presents the self-healing performance of biogranule containing biomortar specimens under intermittent wet/dry conditions. In-house produced biogranules were incorporated into mortar specimens at a dose of 1.45% w/w cement (1.00% of bacteria w/w cement) and self-healing performance of cracked specimens were investigated under alternating wet/dry conditions for a crack width range of 50 to 600 um. Upon alternating wet/dry treatment for 4 weeks, cracks up to a 400 um crack width were effectively healed in biomortar specimens. Their water tightness regain was 44% better than control specimens due to their enhanced healing performance. Overall, non-axenic biogranules appear to be useful in development of self-healing bioconcrete for applications under spraying or intermittent wetting conditions.
  • Article
    Ball Lens Based Mobile Microscope
    (Gazi Univ, 2016) Icoz, Kutay
    In this paper we report a low cost, simple and mobile microscope based on attachment of a ball lens to a cell phone. The system's noise and parameters affecting the image quality is investigated. The ball lens provides approximately 100X magnification and together with the cell phone's integrated lens and image sensor, 3,4-micron resolution is reached. The field-of-view of the system is 1500x1500 mu m where the price of the ball lens and the holder is less than 10 cents. By using this system as an optical light microscope, we are able to acquire images of micro particles and micro sensors. When combined with image processing methods, this optical system is capable of doing complex analysis as an alternative to commercial optical light microscopes.