2021 Cilt 26 Sayı 1

Permanent URI for this collectionhttps://hdl.handle.net/11452/20111

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Now showing 1 - 9 of 9

Ambient vibration analysis of an industrial building
(Bursa Uludağ Üniversitesi, 2021-01-03) Kartal, Hüseyin; Dere, Yunus; Arslan, Musa Hakan
Due to the heavy and dynamic equipment, the vibration and resonance effects that are not encountered under static dead loading may amplify over time in industrial buildings. This might cause damage to the structural system and create human comfort problems while the structure is in service. In this study, ambient vibration testing of a building composed of reinforced concrete and steel structural systems and located at a boron processing plant in Turkey was performed. The velocities and accelerations caused by the sieve shaker system attached to the structure with springs, are evaluated under the effect of sample loading.
Calculation of coverage and flake size of monolayers grown by chemical vapor deposition technique
(Bursa Uludağ Üniversitesi, 2021-02-15) Aslancı, Fırat; Can, Fatma; Öper, Merve; Perkgöz, Nihan Kosku
Two-dimensional (2D) materials such as transition metal dichalcogenides (TMDs) are prominent candidates to be utilized in integrated circuits. However, growing uniform and large-area 2D materials, specifically monolayers, that can be used in electronic component production is still one of the main challenges for these 2D materials to be incorporated in integrated circuits or other active device applications. The aim of this study is to demonstrate a practical and reliable MATLAB computational method, which calculates the ratio of the chemical vapor deposited monolayers to the whole substrate surface and the maximum area of the deposited flakes. In this study, we used the K-means clustering method to calculate surface coverage where we obtained accuracy of ~96% for the simple test images (single star and hexagonal shapes).For the multi-numbered and distributed shapes example, we achieved higher accuracy of ~98%. We also realized calculation of each flake area with ~99% accuracy indicating the flake with the maximum area. The practical calculation of the surface coverage ratio and flake size will allow for easy identification of the effects of the process parameters during novel material growth, which will pave way for future optoelectronic and electronic devices.
EEG analysis of real and imaginary arm movements by spectral coherence
(Bursa Uludağ Üniversitesi, 2021-01-23) Özmen, Nurhan Gürsel
Revealing the information between similar patterns of brain for areal motor task and its imaginary equivalent can be means to clarify movement intentions and help to improve Brain Computer Interfaces (BCI)s. This paperuses spectral coherence to assess the functional interactions between neural regions engaged in a real and an imagined arm movement task. Magnitude squared coherence values were calculatedfor two specific bands ofElectroencephalogram (EEG) that are 8–12 Hzalpha band and 13–20 Hz betafor 48 channelsfrom selectedregions of interest (ROIs). The coherence values are transferred into surfacemaps. We try to explainhowmotor cognition in these regions are relevant with the literature. Themaximum coherence is observed between the channels in the same hemisphere and surrounding closest channels located vertically and horizontally based on the 10-20 electrode placement. Our results that the supplementary motor area, the premotor, prefrontal, primary motor cortex and the parietal cortexplay a role in facilitating real and imaginary motor movements, are in good accordance with the previous studies. Further research can be put on spectral coherence patterns which would be a possible means for prosthetic-interactive BCI systems, interactive multimedia applications, and emerging EEG-based biometric recognition areas.
Experimental and numerical investigation of the frictional forces in equal channel angular pressing
(Bursa Uludağ Üniversitesi, 2021-03-28) Eskandarzade, Mehdi; Ershadi, Meysam Najafi
The main limitation of the Equal Channel Angular Pressing (ECAP) isthevery high required punching force for pushing the metallic sample to next channel. Frictional forces in ECAP process are responsible for very high required punching force. The participation of exit and entrance channels in total friction force has not been studied experimentally hitherto. Through the current study, two ECAP dies (1) with two channels (normal ECAP die) and (2) with only one channel (the exit channel was missed) were manufactured. Three-dimensional finite element analysis was conducted. The effect of the exit channel on the total punching force, sample geometry, and grainrefinement rate were investigated experimentally and numerically. According to the results, the exit channel has a considerable effect on the amount of minimum required punching force and the grain refinement in ECAP process. The comparisons showed that, the trend of the results from experimental investigations were in good agreement with numerical analysis.
Incremental dynamic analysis of mid-rise rc buildings to assess effect of concrete strength and tension reinforcement ratio in beam
(Bursa Uludağ Üniversitesi, 2021-02-07) Onat, Onur; Yön, Burak
IDA is a parametric analysis method that has used commonly in several different forms to assess the structural performance under seismic loadings. This paper focuses on the effect of tension reinforcement ratio and concrete strength to performance of reinforced concrete (RC) structures. For numerical analysis, two RC frame type structures were selected. One of them is 5 stories other of them is 7 stories. Two different concrete class, C20 and C25, were considered and three tension reinforcement ratios were considered for analyses. Tension reinforcement ratios were determined half of the compressive reinforcement, equal to compressive reinforcement and double of compressive reinforcement ratio. Incremental dynamic analyses (IDA) were performed on these buildings. In this study to execute IDA, eleven seismic acceleration benchmark records were multiplied with various scaling factors from 0.2 to 1.2. Maximum base shear and corresponding roof displacement responses obtained from IDA curves were generated according to these responses. IDA curves were compared with each other by using suitable graphs. According to analyses results, increasing tension reinforcement of beam elements has not any effect on maximum roof displacement. Whereas, increasing of tension reinforcement decreased interstorey drift ratio. This result limited the damage due to decreased interstorey drift ratio.
Leakage analysis of the RSOR algorithm
(Bursa Uludağ Üniversitesi, 2021-04-09) Hatun, Metin; Mühendislik Fakültesi; Elektrik Elektronik Mühendisliği Bölümü; 0000-0003-0279-5508
The RSOR algorithm is a recursive algorithm that has been proposed as an alternative to the RLS algorithm for updating adaptive filter parameters. As with other algorithms, the forgetting factor, filter length and relaxation parameter significantly affects the performance of the RSOR algorithm. In this study, using an adaptive FIR filter in system identification mode, the effect of forgetting factor, filter length and relaxation parameter on the leakage phenomenon of the RSOR algorithm was analyzed. For this purpose, firstly, the effect of measurement noise on the adaptive filter output, namely the leakage phenomenon, was explained analytically, and then the influence of the forgetting factor and other filter parameters on this leakage phenomenon was examined. The results obtained from the simulation studies are compared with similar algorithms.
Moment-rotation characteristics and finite element analysis of cold formed steel connections
(Bursa Uludağ Üniversitesi, 2021-01-18) Alemdar, Fatih; Geleta, Hunde Dechasa; Algaadi, Fuad Mohammed
The connections are used to transfer forces and moments due to applied loading. The capability of the connection in the resisting moment is used to classify the types of connections in steelwork particularly for cold-formed steel. Classification schemes based on the total moment-rotation behavior have been developed to aid in the design and analysis of connections. Moment-rotation curve commonly used to describe the connection behavior that can be obtained from either theoretical or experimental study. It is often inappropriate to define the connections as either rigid or pinned due to their high non-linear behavior. Therefore, the lightweight cold formed steel connections have been classified into simple, semi-rigid, and rigid connections according to their strength and rigidity, and discussed in detail. Three-dimensional finite element model of lightweight cold formed steel connection under cyclic loading was generated to investigate and study their behavior. Two lipped sigma sections back-to-back with interconnections are used as beam and column members. Finally, the connection type of lightweight cold formed steel connections have been found to be as semi-rigid, and the key factors influencing stiffness is the bearing forces around the bolt hole.
Noise cancellation with LMS variants
(Bursa Uludağ Üniversitesi, 2021-02-02) Vatansever, Fahri; Mühendislik Fakültesi; Elektrik Elektronik Mühendisliği Bölüm; 0000-0002-3885-8622
The noise is one of the important factors that affect negatively the operation of circuits and systems.There are different methods and techniques for cancelling/reducing/de-noising these unwanted signals that mix with the original signal.In thisstudy, an application/simulator that performs noise cancellation operations with least mean-squares algorithms was designed.The application, which has powerful visual support and a user-friendly interactive interface, can make single or comparative noise cancellation operations and performance analyzes with different algorithms on noisy signals. The effects of thealgorithm parameters can be observed, information about the related algorithms can be obtained via the developed application that can also be used for educational purpose.
Rule generation based on modified cuttlefish algorithm for intrusion detection system
(Bursa Uludağ Üniversitesi, 2021-01-25) Eesa, Adel Sabry; Sadiq, Sheren; Hassan, Masoud Muhammed; Orman, Zeynep
Nowadays, with the rapid prevalence of networked machines and Internet technologies, intrusion detection systems are increasingly in demand. Consequently, numerous illicit activities by external and internal attackers need to be detected. Thus, earlier detection of such activities is necessary for protecting data and information. In this paper, we investigated the use of the Cuttlefish optimization algorithm as a new rule generation method for the classification task to deal with the intrusion detection problem. The effectiveness of the proposed method was tested using KDD Cup 99 dataset based on different evaluation methods. The obtained results were also compared with the results obtained by some classical well-known algorithms namely Decision Tree (DT), Naïve Bayes (NB), Support Vector Machine (SVM), and K-Nearest Neighborhood (K-NN). Our experimental results showed that the proposed method demonstrates a good classification performance and provides significantly preferable results when compared with the performance of other traditional algorithms. The proposed method produced 93.9%, 92.2%, and 94.7% in terms of precision, recall, and area under curve, respectively.

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