TR-Dizin İndeksli Yayınlar Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8652

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Architectural Design - Structural System Conformity Problems Encountered in the Design and Application Processes of Stick Aluminium Curtain Wall Systems in Turkey
(Gazi Univ, Fac Engineering Architecture, 2022) Ozmen, Cengiz; Saban, Muge
Stick aluminium curtain wall (SACW) systems are common curtain wall systems in Turkey. These sytems offer many advantages including architectural variation, modular design, ease of production and assembly. Beside their architectural properties SACW systems create significant load effects on structural systems. These load effects include lateral loads such as seismic and wind loads as well as static vertical loads. This load transfer is not one way. The vertical and lateral displacements of building structures also act on curtain walls. Healthy load transfer between the SACW and the building depends on architectural decisions during the design and construction process. Due to their wide use SACW systems are prone to architectural mistakes. These mistakes often represent themselves at latter stages of the construction and require solutions which will affect the architectural characteristics and structural behavior of buildings. This study focuses on SACW design and construction processes to find the effects of architectural decisions on curtain wall behavior. Case studies that include architectural design mistakes are selected to classify and study the reasons and the solutions of these mistakes. The importance of cooperation between all the stakeholders including the architects and engineers is emphasized for the prevention of these mistakes.
Citation - WoS: 11
Citation - Scopus: 16
Artificial Intelligence Applications in Earthquake Resistant Architectural Design: Determination of Irregular Structural Systems With Deep Learning and Imageai Method
(Gazi Univ, Fac Engineering Architecture, 2020) Bingol, Kaan; Akan, Asli Er; Ormecioglu, Hilal Tugba; Er, Arzu
Although the architectural design process is carried out with the collaboration of experts who are experienced in many different areas from the main preferences to the detailing stage, the major decisions such as plan organization, mass design etc. are taken by the architect. Computer Aided Design (CAD) programs are generally effective after the major decisions of the design are taken. For this reason, it is common for the main decisions, taken during the design process, to be changed during the analysis of the structural system. In order to prevent this, in the early stages of architectural design, earthquake system awareness and structural system design should be included as an design input; as, the failure of the structural system which did not considered well in the architectural design phase leads to unexpected revisions in the implementation project phase and thus leads to serious losses in both time and cost. The aim of this study is to create an Irregularity Control Assistant (IC Assitant) that can provide architects general information about the appropriateness of structural system decisions to earthquake regulations in the early stages of design process by using the deep learning and image processing methods. In this way, correct decisions will be made in the early stages of the design and unexpected revisions that may occur during the implementation project phase will be prevented.
Citation - WoS: 1
Citation - Scopus: 2
Classification of Low Probability of Intercept Radar Waveforms Using Gabor Wavelets
(Gazi Univ, Fac Engineering Architecture, 2021) Ergezer, Halit
Low Probability of Intercept (LPI Radar) is a class of radar with specific technical characteristics that make it very difficult to intercept with electronic support systems and radar warning receivers. Because of their properties as low power, variable frequency, wide bandwidth, LPI radar waveforms are difficult to intercept by ESM systems. In recent years, studies on the classification of waveforms used by these types of radar have been accelerated. In this study, Time-Frequency Images (TFI) has been obtained from the LPI radars waveforms by using Choi-Williams Distribution method. From these images, feature vectors have been generated using Gabor Wavelet transform. In contrast to many methods in the literature, waveform classification has been performed by directly comparing the feature vectors obtained without using any machine learning method. With the method we propose, classification accuracies were obtained at intervals of 2 dB between -20 dB and 10 dB and performed at reasonable classification accuracy rates up to -8 dB SNR value. Better results than the best reported in the literature were obtained for some signal types. The results obtained for all waveform types are given in comparison with the results of the existing methods in the literature.
Citation - WoS: 2
Citation - Scopus: 2
Development of Air-To Engagement Analysis Model of Fighter Aircrafts
(Gazi Univ, Fac Engineering Architecture, 2022) Bektas, Almila; Ergezer, Halit; Erdogan, Sinem
In operational analysis studies; it is possible to model and simulate at an engineering level, engagement level, task level and campaign forces level. In this study, modelling and simulation studies are performed in engagement-level allowing the analysis of air-to-ground engagement effectiveness of fighter aircraft according to the operational environment. The operating environment of the combat aircraft, which provides survivability analysis based on low visibility and electronic mixing capabilities, is created. The search radar and tracking radar models for ground-to-air threats have been designed in accordance with the engagement level. The dynamic model of the fighter aircraft and the ground-to-air missile have been modelled using pseudo 5 degree-of-freedom. Modelling has been carried out to allow the use of changes in the Radar Crosssectional Area (RCS), which is one of the most important factors affecting the survivability of the aircraft, with respect to azimuth and elevation angles. The Radio Frequency (RF) jamming capability of the fighter aircraft has also been modelled in accordance with the engagement level. The results of the generic scenarios for the analysis of the effect of these models' parameters on the survivability of fighter aircraft have been presented.
Citation - WoS: 1
Effects of Sound Absorption Materials on Reverberation Time According To Their Positions in the Square Plan and High Ceiling Rooms
(Gazi Univ, Fac Engineering Architecture, 2021) Kurtay, Cuneyt; Harputlugil, Gulsu Ulukavak; Yaman, Muammer
In rooms with speech action, subjective and objective room acoustics parameters should be considered in the creation of acoustic performance. In this study, an evaluation has been made over the reverberation time for the speech action of the existing Iraq-Najaf Islamic University Alawiya Conference Hall. Within the scope of the study, the control of the reverberation time affecting the subjective and objective room acoustics parameters has been examined, the relationship between the reverberation time and the surface absorptions of the room have been examined. Reverberation time on existing situation was determined by making in situ measurements. In order to control the reverberation time of the existing hall, the materials selected according to the sound absorption coefficients have been positioned differently and alternative models have been developed. The reverberation times of the alternative models were determined using the ECOTECT v.5.20 computer simulation program used for acoustic analysis, and their geometric acoustics analysis was performed using the ray tracing method. By comparing the models, the surface absorptions have been analyzed to obtain the appropriate reverberation time in room for speech action. As a result of the study, the effects of the use of walls, ceiling and floor finishing materials and surface absorptions on the reverberation time have been evaluated within the scope of improvement for speech action in the halls with square plan, flat floor and high ceiling (min 6 m).
Citation - WoS: 3
Citation - Scopus: 3
Exploring Fire Safety Conditions of Double Skin Facades
(Gazi Univ, Fac Engineering Architecture, 2024) Aslar, Eylem Ezgi; Harputlugil, Gulsu Ulukavak
Human health, comfort and safety are of primary importance in the built environment. Among the security measures, the most important risk is the risk of fire. For this reason, the issue of fire risk, spread and safety is considered as one of the criteria that should be considered from the building design stage. Within the scope of this study, building models with the same floor height, different plan and facade types, designed in 3D, were analyzed in the fire simulation program called PyroSim. Based on the data obtained as a result of the analyzes, the results of the temperature, smoke and flame spread at the time of fire according to the facade and plan types are presented in tables. As a result of the data obtained, it was determined that box-type systems in double-layer facades are the most problematic facade type in terms of evacuation of living creatures. In terms of smoke spread, it has been revealed that the systems that continue uninterruptedly along the facade pose a problem when the access and spread to other floors are taken into account. It is necessary to consider fire safety as a design problem. It is considered that more detailed studies should be carried out in our country on this subject, that the project should be designed by considering the simulations from the decision stage to the implementation stage of the building, and that the regulations should be developed in order to be a good guide in both the design and implementation stages.
Frame Finite Element Model for Nonlinear and Vibration Analysis of Steel Structures With Beam-Column and Column-Base Semi-Rigid Connections
(Gazi Univ, Fac Engineering Architecture, 2022) Saritas, Afsin; Ozel, Halil Firat
In this paper, a shear deformable force-based frame finite element with semi-rigid connections is derived for nonlinear analysis of steel structures. Distributed plasticity approach is defined along element length and section depth, and linear or non-linear semi-rigid connection behavior can be specified anywhere along elements without the necessity to define additional nodes and to increase the degrees of freedom of the structural system. To perform vibration analyses with similar accuracy, force-based consistent mass matrix is used considering semi-rigidity in connections and an appropriate shear correction coefficient for I-sections. The element formulation is presented in 2 dimensions to simplify the formulation, and numerical validation and comparison studies are carried out on complex and irregular structures in 2-D and 3-D. In models with semi-rigid connections, the effect of nonlinear behavior on the structural system has been studied in both beam-column and column-bases. In the presented examples, it was possible to push structures higher than the existing displacements, and it was revealed that the nonlinear behavior in the column-base connections could create much more critical results for the structural systems with P-Delta effects. In addition, high-level accuracy results were obtained when performing vibration analyses with the application of force-based consistent mass matrix.
Investigation of Factors Affecting Noise Robustness in Voice Activity Detectors
(Gazi Univ, Fac Engineering Architecture, 2023) Ozaydin, Selma
In this manuscript, some voice activity detectors (VADs) in the literature were examined in terms of factors affecting their robustness under different acoustic noise conditions and in this context, the changes in detection accuracy rates according to changing noise conditions were tested. In this scope, the effect of situations such as whether the threshold value used in the decision phase in VAD methods is fixed or adaptive, the analysis window is short or long, the use of more than one feature vector together has been evaluated and analyzed comparatively. While three of the four different VAD detectors examined in this manuscript use feature vectors within the short-term analysis window while generating the decision result, one decides according to the measurement result of long-term spectral vectors. The VAD detectors in the article have been tested using the NOIZEUS noisy speech database. Thus, the performance of the analyzed VADs has been evaluated under different acoustic conditions using an extensive database that has already taken place in the literature. During the testing of the analyzed VADs, different input noise speech signals with environmental background noises between [15-0dB] such as restaurant, car, street, or station were tested. Tests were carried out using objective test measurement methods and the detection accuracy rate of each VAD method was measured. The results showed that each method gave different endurance performance in adverse environmental conditions.
A Research on Comparison of Elevator Traffic Analysis Methods in Educational Buildings
(Gazi Univ, Fac Engineering Architecture, 2023) Harputlugil, Timucin; Deligoez, Dostcan
Purpose: Regarding elevator design in educational buildings; It is aimed to investigate the legal framework, to integrate dynamic simulation programs to design process, to compare traditional and dynamic simulation methods, to evaluate the adequacy of elevator features specified in the legislation and to determine the optimum scenarios according to the minimum requirements.Theory and Methods: Based on the findings of the literature review, which examines the issue of elevator traffic analysis together with the legislation and regulations, the carrying capacities of the elevators in the educational buildings designed by the Ministry of National Education (MNE) are tested. The stability of the system is tested by analyzing the conditions where only the disabled, disabled and building workers can be used together and all building users can use the elevators with the dynamic simulation method (with Elevate Software). The limits of the system are determined based on the waiting times during the peak usage periods. The findings of the study are evaluated according to the waiting times determined by CIBSE Guide D and the Chamber of Mechanical Engineers followed by the discussion of the outcomes.Results: The issue of elevator design has been overlooked in educational buildings, and a comprehensive elevator traffic analysis method has not been defined. For the effective use of all occupants, elevator design should be handled comprehensively with considering potentials of dynamic simulation method.Conclusion: According to the findings of the study, it is noted that the number and capacity of elevators in the legislation for educational buildings are determined only for minimum conditions and for disabled users. In addition, the legislation (considering calculation methodology) is not specific for educational buildings but related with buildings in general with public use. Considering the occupants, and their profiles of the educational buildings, a more comprehensive traffic analysis with the dynamic simulation method may enable the elevators to be designed and to be used more efficiently.

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