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Article Citation - WoS: 1Citation - Scopus: 2A Miniaturized Multi-Layer Microstrip Antenna for Linear Wireless Sensor Network Monitoring Systems(Gazi Univ, 2022) Kara, Ali; Aydın, Elif; Benzaghta, Mohamed; Er, Burak; Bilgin, GulsimaThis article presents a sub-GHz ISM band microstrip patch antenna based on the use of multi-layer compact structure, which overcomes the shortcomings of typical microstrip antennas such as low gain and high resonant frequency. The antenna was simulated using an electromagnetic simulator, ANSYS HFSS, and fabricated on two different substrates: RT Duroid 5880 and FR4 epoxy with a compact size of 100 x 100 x 8 mm3 (0.29λ × 0.29λ × 0.02λ). The simulated results of the antenna were then compared with the measured ones, and the two were observed to have a reasonable agreement. The proposed antenna operates in the sub-GHz license-free ISM band (862-875 MHz), with a gain value of 2.92 dB. Two prototypes of the proposed antenna were fabricated and used in a Linear Wireless Sensor Networks (LWSNs) monitoring system. Results show that the proposed antenna is a good candidate for those types of LWSNs systems.Article Citation - WoS: 1Citation - Scopus: 1A New Multi-Target Compiler Architecture for Edge-Devices and Cloud Management(Gazi Univ, 2022) Gokcay, ErhanEdge computing is the concept where the computation is handled at edge-devices. The transfer of the computation from servers to edge-devices will decrease the massive amount of data transfer generated by edge-devices. There are several efficient management tools for setup and connection purposes, but these management tools cannot provide a unified programming system from a single source code/project. Even though it is possible to control each device efficiently, a global view of the computation is missing in a programming project that includes several edge-devices for computation and data analysis purposes, and the devices need to be programmed individually. A generic workflow engine might automate part of the problem using standard interfaces and predefined objects miming on edge-devices. Nevertheless, the approach fails in fine-tuning each edge-device since the computation cannot be moved easily among devices. This paper introduces a new compiler architecture to control and program edge-devices from a single source code. The source code can be distributed to multiple edge-devices using simple compiler directives, and the transfer and communication of the source code with multiple devices are handled transparently. Fine-tuning the source code and code movement between devices becomes very efficient in editing and time. The proposed architecture is a lightweight system with fine-tuned computation and distribution among devices.Article Citation - WoS: 2Citation - Scopus: 2Low Carbon Architectural Design(Gazi Univ, 2018) Balku, Saziye; Bal Kocyigit, Filiz; Architecture; Energy Systems EngineeringTendency towards sustainable energy resources is increasing and leading engineers and architects make joint efforts. Renewable energy potential present in nature can be used more efficiently so that while energy consumption is reducing, rate of energy gain, on the other hand, increases by architectural design methods. A sailing club in Golbasi, Ankara is designed as a low carbon building for optimum usage of solar and wind energy. It can be concluded using an energy efficient architectural design for a building before its construction makes it possible to meet the electrical and heat energy requirements at minimum cost and environmental friendly.Article Citation - WoS: 7Citation - Scopus: 10Comparison of Three Different Learning Methods of Multilayer Perceptron Neural Network for Wind Speed Forecasting(Gazi Univ, 2021) Bulut, Mehmet; Tora, Hakan; Buaisha, Dr.magdiIn the world, electric power is the highest need for high prosperity and comfortable living standards. The security of energy supply is an essential concept in national energy management. Therefore, ensuring the security of electricity supply requires accurate estimates of electricity demand. The share of electricity generation from renewables is significantly growing in the world. This kind of energy types are dependent on weather conditions as the wind and solar energies. There are two vital requirements to locate and measure specific systems to utilize wind power: modelling and forecasting of the wind velocity. To this end, using only 4 years of measured meteorological data, the present research attempts to estimate the related speed of wind within the Libyan Mediterranean coast with the help of ANN (artificial neural networking) with three different learning algorithms, which are Levenberg-Marquardt, Bayesian Regularization and Scaled Conjugate Gradient. Conclusions reached in this study show that wind speed can be estimated within acceptable limits using a limited set of meteorological data. In the results obtained, it was seen that the SCG algorithm gave better results in tests in this study with less data.Article Citation - WoS: 2Measuring Dependence Between Electricity Consumption and Economic Indicators Via Copulas: Turkish Case(Gazi Univ, 2018) Evkaya, O. Ozan; Yozgatligil, Ceylan; Selcuk-Kestel, A. Sevtap; MathematicsThis paper implements copulas to identify the dependence structure between electricity consumption and its cofounding indicators. To achieve this, Turkish electricity demand, its economic and sectoral indicators are taken into account. As a first step, bivariate copulas are used to identify the best fitting copula and the degree of the dependence. Thereafter, multivariate model is established using vine copulas using highly correlated variables. The empirical results confirm the added value of the proposed approach in determining numerous tail properties. We indicate that the copulas are useful to underline, especially, the tail properties of indicators in the market for decision makers.Article Citation - WoS: 3On the Yielding of Two-Layer Composite Spherical Pressure Vessels(Gazi Univ, 2017) Akis, TolgaThe yielding of two-layer composite spherical pressure vessels under either internal or external pressure is investigated analytically in the framework of small deformations and von Mises yield criterion. It is shown for both pressure cases that depending on the material properties and sphere dimensions, different modes of plasticization may take place. Unlike the deformation behavior of a single layer spherical pressure vessel, yielding may commence at the inner layer or at the outer layer or simultaneously at both layers of the assembly.Article A Modeling Approach for Designing New Acoustic Materials(Gazi Univ, 2024) Koçyiğit, Filiz Bal; Köse, Ercan; Buluklu, Hatice MehtapIn this study, mathematical modeling design based on Sound Transmission Loss measurement results of new acoustic material samples with natural content was carried out. Using the test samples in question, transfer function of acoustic materials based on electronic filter circuit design and a transition design method for the production of new acoustic materials by utilizing the transfer function is presented. Based on the experimental results of the test samples, it is the most suitable low-pass filter structure for the proposed design. In this study, active Sallen-Key low-pass filter structure is preferred and used. Sound Transmission Losses in dB (decibels) of acoustic samples were obtained experimentally for 500, 1000, 2000 and 4000 Hz. fundamental frequencies in the literature. Based on these data, transfer function simulation suppression gain results were obtained in TINA-TI program, active filter circuit designed, and MATLAB program. When the other results were compared in the experimental results, it was seen that very close values were obtained. It has been demonstrated that the proposed method can be used effectively in the design and examination of new acoustic materials.Article Citation - WoS: 2Citation - Scopus: 3Low-Cost Alpha Cabin Like Test Box Proposal for the Development of New Acoustic Sound Insulation Materials(Gazi Univ, 2023) Koçyiğit, Filiz Bal; Köse, Ercan; Buluklu, Hatice MehtapExperimental criteria for sound insulation material recommendation and design have an important share in indoor acoustic control. Among these criteria, laboratories with devices such as impedance tubes, alpha cabins and reverberation rooms used to measure and analyze parameters such as sound transmission loss and sound absorption coefficient have been investigated. In literature, it has been observed that there are studies on acoustic materials and the tests applied to these materials, but the application is more limited. According to research data, an Alpha Cabin model system design that can be used to develop new types of acoustic sound materials has been proposed. In addition to the fact that a large number of experimental measurements can be performed at lower costs using the designed Alpha Cabin model system, many tests can be performed easily for different material designs in a very short time. To perform these tests, the Alpha Cabin system has been designed based on noise and sound insulation. For example, floating flooring, ribbed connection, and so on. Afterward, different insulation materials were used for insulation purposes and standards were achieved. The Alpha Cabin test system, which was designed and developed, overlaps the experimental and theoretical data for 500, 2000, and 4000 Hz when compared with the values of 29.1 dB for 500 Hz, 38.6 dB for 2000 Hz, and 49 dB for 4000 Hz measured in the Acoustic Facade Panel Test Room, and it has been observed that it can be used in the development of new sound insulation materials.Article Citation - WoS: 1Zero Consumption Monotype Education Buildings(Gazi Univ, 2018) Bal Kocyigit, FilizTurkey has mainly seven geographic zones but four climatic zones. Major influence on energy usage and educational buildings which perform well in energy terms will reap significant environmental and economic benefits for years to come. The lack of electric, heating-cooling and lighting comfort in the structure reduce the quality of education. Many village schools cannot provide training in enough conditions. Municipalities are preparing "Type School Project" for government schools, without thinking different zones conditions, directions and heights. At this stage, there arises importance of the Architectural Design Process for typical energy efficient design which can easily adapt to the location. The material must not only be transmits about 70-90% of solar radiation, but also its insulation quality. Additionally architectural form of building must be affected to take all solar energy, wind and water. In this study, architectural design method has been used for energy gain from transparent insulated trombe wall. And have been calculated in accordance with their manners in the middle, south, noth, east and west regions of Anatolia which are located in different degree-days regions on the basis of TS 825.Article Citation - WoS: 4Betonarme Binaların Yapım Maliyeti ve Deprem Davranışında Döşeme Tipinin Etkisi(Gazi Univ, 2023) Tunç, Gökhan; Azizi, Abdul Basir; Tanfener, TuğrulTürkiye’de betonarme çerçeveli binalar diğer tür yapı taşıyıcı sistemlerine göre en çok tercih edilmektedir. Bu tür binalarda kullanılan yaygın döşeme türleri ise kirişli, kirişsiz, kaset ve nervürlü olanlarıdır. Bir bina tasarımında, yatay ve düşey yükler altında en iyi performansı gösteren ve aynı zamanda en az maliyet gerektiren döşeme türünün belirlenmesi istenir. Ancak, kirişler, kolonlar ve perde duvarlar gibi diğer yapı elemanlarına analitik çalışmalarda öncelik verildiğinden, döşeme türünün uygun seçimi genellikle tasarımcı tarafından göz ardı edilir. Bu nedenle, döşemelerin bina tasarımına ve yapısal davranışına sağlayacakları katkılar yeterince irdelenmemiş olur. Ortaya çıkan bu eksikliğin ise binanın tasarım aşamasından itibaren detaylı olarak irdelenmesi gerekmektedir. Bu çalışmada çok katlı betonarme binalar üzerinde farklı döşeme türlerinin etkileri incelenirken aynı zamanda toplam maliyetin de optimumda kılınması hedeflenmiştir. Bu amaç doğrultusunda toplamda 36 bina modeli hazırlanarak, analiz ve tasarımları mevcut Türkiye bina yönetmelik ve standartlarına uygun olarak yapılmıştır. Bu kapsamda yapılan analitik çalışmalarda incelenen parametreler şu şekildedir: döşeme türleri (kirişli, kirişsiz, kaset ve nervürlü), toplam kat sayıları (10, 20 ve 30) ve tip döşeme açıklıkları (6, 7.5 ve 9 metre). Binaların tümünün iş yeri kullanımına uygun olarak İstanbul’un deprem tehlikesi içeren bir bölgesinde yer aldığı kabul edilmiştir. Yapılan analitik çalışmalara göre 6 metre açıklığa sahip binalarda en ekonomik sonucun kirişli, 7.5 metre açıklığa sahip olanlarda ise kaset döşemelerde olduğu görülmüştür. Ele alınan tüm modeller içerisinde en maliyetli çözümü üreten döşeme türü kirişsiz döşeme olarak belirlenmiştir. İncelenen tüm döşeme türleri arasında, kirişli döşemeye sahip binaların en iyi deprem performansına, kaset ve kirişsiz döşeme türlerine sahip binaların ise en olumsuz deprem performansına sahip oldukları görülmüştür.
