Yazarlar
- Tozlu, Alperen(13)
- Ergün, Mustafa(11)
- Artar, Musa(10)
- Cuce, Erdem(9)
- Cuce, Pinar Mert(8)
- Yurdakul, Muhammet(8)
- Imamoglu, Ilyas Kays(7)
- Esmer, Yusuf(6)
- Isik, Cem(6)
- Ongan, Serdar(6)
- Can, Ömer(5)
- Guclu, Tamer(5)
- Kahveci, Hakan(5)
- Tayfur, Bilal(5)
- Yilmaz, Fatih(5)
- Ates, Sevket(4)
- Guler, Evrim(4)
- Gökçe, H.S.(4)
- Karakus, Murat(4)
- Tapkın, Serkan(4)
- Tercan, Emre(4)
- Çaglar, Hakan(4)
- Özahi, Emrah(4)
- Abdioglu, Murat(3)
- Abusoglu, Aysegul(3)
- Altuntas, Serkan(3)
- Ateş, Şevket(3)
- Ayberkin, Doruk(3)
- Aydin, Rahman(3)
- Cakici, Ziya(3)
- Cakir, Mehmet(3)
- Carbas, Serdar(3)
- Dereli, Turkay(3)
- Engin, Mustafa Alptekin(3)
- Gökçe, H. Süleyman(3)
- Güngör, Okan(3)
- Kiral, Adnan(3)
- Kuziboev, Bekhzod(3)
- Murat, Yetis Sazi(3)
- Okur, Fatih Yesevi(3)
Yayınlar
- MakaleAçık Erişim2023Performing trajectory tracking control of an unmanned ground vehicle using fractional order terminal sliding mode controller
Sekban, Hayriye Tuǧba; Başçi, Abdullah
In this paper, fractional order terminal sliding mode control (FOTSMC) method is used for trajectory tracking control performance of an unmanned ground vehicle (UGV). Firstly, a kinematic controller is designed to estimate the linear and angular velocities of the vehicle. Then, a FOTSMC design is carried out to track the vehicle reference velocities. Terminal sliding mode control (TSMC) and sliding mode control (SMC) methods are also used to demonstrate the performance of the proposed controller. The simulation results show that the proposed controller improves the tracking error by about 13% over SMC and 6.146% compared to TSMC.
AtıfScopus3WoS3OpenAlex3
İncele - Derleme MakaleYalnız künye2023Scopus SJRQ3An overview of frequency-based power split strategies in electric vehicles with battery/supercapacitor hybrid energy storage system
Çorapsız, Muhammed Reşit; Kahveci, Hakan
Energy management in hybrid energy storage systems (HESSs) consisting of battery and supercapacitor packages has an essential role in the efficient and safe use of energy storage devices. In the mentioned HESSs, with frequency separation-based energy management, the source with slow dynamics (eg, batteries) is supported by other sources with fast dynamics (eg, supercapacitors). To realize power sharing in the battery/supercapacitor HESS, the load current is divided into low- and high-frequency components and supplied/allocated from energy storage devices. This review touches on the historical development of electric vehicles and includes extensive information about the battery and supercapacitor. It also comprehensively analyzes frequency separation-based power allocation strategies for battery/supercapacitors HESS. These strategies were investigated in detail regarding their features, advantages, and restrictions. In addition, interconnection circuit topologies and control techniques used in frequency-based power allocation were explained comprehensively. As a result, this study will serve as a guide on frequency-based power separation principles in HESS.
AtıfScopus23WoS14OpenAlex22İncele - MakaleAçık Erişim2023Scopus SJRQ2Investigating the impact of ICT-trade nexus on competitiveness in Eastern and Western European countries
Soylu, Özgür Bayram; Adeleye, Bosede Ngozi; Ergül, Murat; Okur, Fatih; Lorente, Daniel Balsalobre
Purpose: Since competitiveness is crucial in international trade, this paper contributes to the literature by interrogating the information and communication technology (ICT)-trade nexus on competitiveness in Eastern and Western European countries. Does ICT usage promote or hinder the impact of trade openness on competitiveness? This study attempts to answer two questions: (1) is the interaction of trade and ICT significant in promoting competitiveness? (2) Is the effect significantly different by European classification? Design/methodology/approach: With data on 17 European countries from 2007 to 2020 and using mobile phones and fixed telephone usage as ICT indicators, the study engages the bootstrapped ordinary least squares (BOLS) and method of moments quantile regression (MM-QR) techniques to probe the discourse. Findings: The empirical findings reveal that (1) the interaction of trade and ICT boost competitiveness; (2) the effect of mobile phone is consistent across the full, East, and West European samples; (3) the interaction effect is also significant across the conditional distribution of competitiveness and (4) mobile phones and fixed broadband usage reveal “leapfrog” effect across the quantiles. Overall, the study submits that ICT usage will enhance the impact of trade, and thus, ICT is a critical enabler of competitiveness in Europe; policy recommendations were discussed. Originality/value: To the best of the authors' knowledge, this is the first study examining the interaction effect of trade openness and ICT usage on competitiveness in Europe. In other words, the authors attempt to analyze how ICT usage influences trade-competitiveness dynamics. To fill the gap in the literature, the authors' use a sample of 17 European countries from 2007 to 2020. The variables of interest are the competitiveness index, trade openness, and four ICT indicators (mobile phone, fixed telephone subscriptions, fixed telephone subscriptions, and Internet users).
AtıfScopus16WoS13OpenAlex16İncele - MakaleYalnız künye2023Scopus SJRQ2An algorithmic application with flexible airspace approach
Kökhan, Ahmet; Kökhan, Serhan; Gökdalay, Meriç
Purpose: The purpose of this study is to develop an operational level decision support system model for air traffic controllers (ATCos) within the framework of the Flexible Use of Airspace (FUA) concept to enable more efficient use of airspace capacity. This study produces a systematic solution to the route selection process so that the ATCo can determine the most efficient route with an operational decision support system model using Dijkstra’s Shortest Path Algorithm. Design/methodology/approach: In this study, a new decision support system model for ATCos in decision-making positions was recommended and used. ATCos use this model as a main model for determining the shortest and safest route for aircraft as an operational-level decision support system. Dijkstra Algorithm, used in the model, is defined step by step and then explained with the pseudocode. Findings: It has been determined that when the FUA concept and DSS are used while the ATCo chooses a route, significant fuel, time and capacity savings are achieved in flight operations. Emissions resulting from the negative environmental effects of air transportation are reduced, and significant capacity increase can be achieved. The operational level decision support system developed in the study was tested with 55 scenarios on the Ankara–Izmir flight route compared to the existing fixed route. The results for the proposed most efficient route were achieved at 11.22% distance (nm), 9.36%-time (min) savings and 837.71 kg CO2 emission savings. Originality/value: As far as the literature is reviewed, most studies aimed at increasing airspace efficiency produce solutions that try to improve rather than replace the normal process. Considering the literature positioning of this study compared to other studies, the proposed model provides a new systematic solution to the problems that cause human-induced route inefficiency within the framework of the FUA concept.
AtıfScopus2WoS2OpenAlex2İncele - MakaleAçık Erişim2023Scopus SJRQ1The effect of various industrial dust particles on the performance of photovoltaic panels in Turkey
Güngör, Okan; Kahveci, Hakan; Gökçe, H. Süleyman
The accumulation of dust is one of the main causes of power loss in photovoltaic (PV) farms, and the effect of dust particles’ size and chemistry on system performance is often overlooked. This study has focused on a comprehensive analysis of the effect of different dust particles collected from common industrial production facilities in Turkey on the performance of PV panels in the indoor laboratory environment. The collected dust samples were analyzed to determine the dust sample particles’ chemical properties, size, character, and topography. The data for dust samples at different weights with changes in maximum power point (MPP) of PV panel has been collected using the artificial solar irradiation source system. Thus, the mathematical correlations (R2≥0.965) between the PV panel Thevenin resistance (RTH), fill factor (FF), MPP, and pollution rate were obtained using these collected data and particle swarm optimization (PSO). According to the results of the obtained mathematical correlations, marble dust is 2.3, 3.4, and 4.2 times less polluting than cement, fly ash, and silica fume, respectively. Additionally, it was observed that smaller dust particles block more light than larger ones of the same weight and reduce MPP, FF while increasing the RTH.
AtıfScopus19WoS14OpenAlex21
İncele - MakaleAçık Erişim2023Scopus SJRQ1Evaluation of Optimal Energy Productıon Usıng Deterministic, Probabilistic and Risky Cases In a Multi-Reservoir System
Bacaksız, Efsun; Opan, Mücahit; Kara Dilek, Zuhal Elif; Karadeniz, Murat
In a multi-reservoir system, the stochastic nature of basin data resulting from rainfall introduces risk into water management operations. Effective management that accounts for these risks can obtain maximum benefits from the system. This study presents a description of a multi-reservoir water resources system with hydroelectric power plants, utilizing the energy optimization model developed by OPAN in 2007. The model was applied to reservoirs located successively on the Lower Kızılırmak River in the Kızılırmak Basin, with the objective function being the maximization of firm power by using drought period inflows and total energy by using monthly average inflows. The study considered three scenarios: deterministic, probabilistic, and risky (critical cases), with probabilities of inflows from the basin being determined for the latter. Monthly inflows with determined probabilities were used to obtain data for the risky case. Optimum operating levels were determined based on this data to maximize firm power and total energy. According to the operating levels, the reservoir with the largest useful volume manages the operation. The values obtained from the optimization were then used in multivariate regression analysis using the Statistical Package for Social Scientists (SPSS), a statistical analysis program. The analysis explored the effects of monthly operating levels in the reservoirs, the amount of inflow released from the spillway, the amount of inflow released for energy production, the monthly average inflow to the reservoirs, and firm power values on energy production.
AtıfScopus7WoS6OpenAlex7İncele - Kitap BölümüAçık Erişim2023Trajectory Tracking Control of an Unmanned Ground Vehicle Based on Fractional Order Terminal Sliding Mode Controller
Sekban, Hayriye Tuğba; Başçi, Abdullah
In this chapter, fractional order terminal sliding mode control (FOTSMC) method, which is a hybrid control approach, is used to improve the trajectory tracking control performance of an unmanned ground vehicle (UGV). First, a kinematic controller design has been carried out to estimate the linear and angular velocities that will stabilize the vehicle asymptotically. Then, FOTSMC, which is a hybrid control method that combines the advantages of fractional control and terminal sliding mode control methods, is proposed to perform vehicle reference velocities tracking. In addition, terminal sliding mode control (TSMC) and sliding mode control (SMC) methods are used for trajectory tracking control of the same vehicle to demonstrate the performance of the proposed controller. Simulation results show that the proposed controller performs trajectory tracking with smaller error and lower amplitude chattering compared to TSMC and SMC.
- MakaleYalnız künye2023Scopus SJRQ1Novel PV Array Reconfiguration and Integration with a Maximum Power Point Tracking Algorithm: RMPPT
Güngör, Okan; Kahveci, Hakan
Partial shading significantly impacts the output power of photovoltaic (PV) arrays. This issue can be addressed by reconfiguring connections or positions of modules within the PV array. However, reconfiguration approaches present some drawbacks including the requirements of manual effort, complex algorithms, difficulty in implementation, and switching matrices that increase power losses. To overcome these issues, we present a low-cost and easily implemented reconfiguration method with integration into a maximum power point tracking (MPPT) algorithm for a PV array. We denote our MPPT approach as reconfigurable MPPT (RMPPT), and verify its applicability using a particle swarm optimization (PSO) algorithm, namely the reconfigurable PSO. Consequently, this approach has enhanced the output power of the PV array by at least 7.2% compared to PNO (perturb and observe) and PSO-based MPPT under realistic weather conditions.
AtıfScopus6WoS5OpenAlex5İncele - MakaleAçık Erişim2023Scopus SJRQ1Optimizing the seismic resilience performance of steel truss bridges by maximum energy dissipation via friction dampers
Artar, Musa; Carbas, Serdar
The primary aim of this study is to propose an innovative design methodology for optimizing the seismic resilience performance of steel truss bridges by dissipating the maximum input seismic energy. Maximum seismic energy dissipation is carried out by means of Pall friction dampers (PFDs), popularly categorized among passive energy-damping devices. PFDs distribute input seismic energy with a slip motion along with friction during an earthquake. For that, it is important to determine the optimal slip load value for the PFDs to start working before the structural elements reach the yield point. To determine the optimal slip load values of the PFDs under earthquake effects, the maximum seismic energy distribution is assured by nature-inspired Squirrel Search (SS) and Water Strider (WS) metaheuristic algorithms for steel truss bridges equipped with PFDs. Finally, steel truss bridges on which PFDs with optimal slip load values have been implemented are optimally designed to achieve the minimal structural weight while satisfying ASD-AISC Code of Practice requirements. In order to demonstrate the validity of the proposed design methodology, two design examples of 113-member and 465-member steel truss bridges steel are presented. The optimal slip loads attained with the SS and WS algorithms by conducting the proposed design methodology are 2.45% and 3.75% of the structural weight for the first design example and 2.64% and 2.63% of the structural weight for the second design example, respectively, which are much lower than those considered in practical applications. Moreover, the numerical results show that by 93.5% and 99.48% maximum distribution rates of input seismic energy are accomplished in the bridges. The results indicate that the proposed design methodology exhibit superior performance in optimizing the seismic resilience performance of steel truss bridges by maximum energy dissipation via friction dampers.
AtıfScopus8WoS4OpenAlex5İncele - MakaleAçık Erişim2023Scopus SJRQ2Computational Intelligence Based Point of Interest Detection by Video Surveillance Implementations
Tercan, Emre; Tapkın, Serkan; Küçük, Furkan; Demirtaş, Ali; Özbayoğlu, Ahmet; Türker, Abdussamet
Latest advancement of the computer vision literature and Convolutional Neural Networks (CNN) reveal many opportunities that are being actively used in various research areas. One of the most important examples for these areas is autonomous vehicles and mapping systems. Point of interest detection is a rising field within autonomous video tracking and autonomous mapping systems. Within the last few years, the number of implementations and research papers started rising due to the advancements in the new deep learning systems. In this paper, our aim is to survey the existing studies implemented on point of interest detection systems that focus on objects on the road (like lanes, road marks), or objects on the roadside (like road signs, restaurants or temporary establishments) so that they can be used for autonomous vehicles and automatic mapping systems. Meanwhile, the roadside point of interest detection problem has been addressed from a transportation industry perspective. At the same time, a deep learning based point of interest detection model based on roadside gas station identification will be introduced as proof of the anticipated concept. Instead of using an internet connection for point of interest retrieval, the proposed model has the capability to work offline for more robustness. A variety of models have been analysed and their detection speed and accuracy performances are compared. Our preliminary results show that it is possible to develop a model achieving a satisfactory real-time performance that can be embedded into autonomous cars such that streaming video analysis and point of interest detection might be achievable in actual utilisation for future implementations.
AtıfScopus1OpenAlex1İncele - MakaleAçık Erişim2023Scopus SJRQ1A bio-inspired solution to alleviate anisotropy of 3D printed engineered cementitious composites (3DP-ECC): Knitting/tilting filaments
Zhou, Wen; McGee, Wes; Gökçe, H. Süleyman; Li, Victor C.
Widely reported anisotropy in 3D printed cementitious structures has been a primary concern to structural integrity, especially for fiber-reinforced cementitious material, e.g., engineered cementitious composites (ECC). To alleviate the anisotropy present in 3D printed ECC (3DP-ECC), two innovative printing patterns, “knitting” and “tilting” filaments, were proposed, mimicking the natural crossed-lamellar structure of conch shells. 3D spatial paths were designed to allocate tensile/flexural resistance to multiple directions and to create an interwoven interface system to strengthen the structure. Four-point bending tests loading from three different directions were conducted. It was found that knitted and tilted filaments revealed superior or comparable bending performance to cast ECC in two favorable orientations. Furthermore, flexural performance in the weakest orientation was notably improved by knitting and tilting, with up-to-179% increases in flexural strength compared with that of parallel filaments. This novel approach holds great promise in alleviating anisotropy of 3DP-ECC without introducing additional reinforcement.
AtıfScopus45WoS39OpenAlex42İncele - MakaleYalnız künye2023Scopus SJRQ1Optimum weight design of steel truss roof systems considering corrosion effect
Yaren Aydoğdu, Afranur; Artar, Musa; Ergün, Mustafa
In this paper, the ideal weight for steel truss roof systems is determined while corrosion is considered. Because one of the most crucial problems that steel truss roof systems may experience during their service life is the effect of corrosion. If a corroded structure is designed without considering this effect during the design phase, significant damages and even collapses may occur before it reaches its service life. For this reason, the aim of this study is to make weight optimizations by considering the corrosion effect of steel truss roof systems. Thus, it has been revealed how corrosion that may develop on the truss members' surfaces affects the structure's overall optimum weight. Swarm intelligence-based algorithm approaches, Ant Colony Optimization (ACO), and Butterfly Optimization Algorithm (BOA) are used for this purpose to determine the optimal weight design of five different steel truss roof systems that were previously researched. The main program, which includes structural analysis (FEA) and optimization algorithms, is coded in the MATLAB programming language. The compression and tension bars selected as the limiting functions of the optimization problems are obtained from the stress, displacement, and slenderness conditions specified in the American Institute of Steel Construction-Allowable Strength Design (AISC-ASD, 1989) standard. It is seen that the optimum weight results obtained from all optimization methods for each structure in the non-corrosive condition are relatively similar. This result proves the correctness of the algorithms proposed in this paper. Then, under the influence of corrosion, the optimal weight designs of the structures are carried out. When the findings for the two cases are examined, it can be seen that the optimum weight values for all structures have slightly increased. This is because larger profiles are required due to overcapacity brought on by section loss. The weight of the structure increases in lockstep with the severity of corrosion. All the results like this are presented in detail with the help of tables and graphs in the relevant sections.
AtıfScopus13WoS11OpenAlex18İncele - MakaleAçık Erişim2022Kendiliğinden Yerleşen Hafif Betonda Mermer Tozu Kullanımının Araştırılması
Avan, Çağrı; Çaglar, Hakan; Çimen, Selçuk; Ahiskali, Adem; Özdemir, Celal
Bu çalışmada, doğal kaynaklarımızdan biri olan Nevşehir bölgesine ait asidik pomza agregası ile Kırşehir bölgesinden elde edilen endüstriyel atık olan atık mermer tozunun kullanılması sonucu kendiliğinden yerleşen hafif beton üretilmesi amaçlanmaktadır. çimento ikame malzemesi olarak farklı oranlarda (%0, %5, %10 ve %15). Çalışma sonucunda fiziksel ve mekanik olarak kendiliğinden yerleşen hafif betondan üstün bir yapı malzemesi elde edilmesi hedeflenmiştir. Bu kapsamda, kendiliğinden yerleşen hafif betonların taze ve sertleşmiş özellikleri araştırılmıştır. Taze beton özelliklerini belirlemek için; taze beton birim ağırlık, çökme-yayılma, V hunisi, L kutu ve U kutu testi ve taze beton birim hacim ağırlık testi yapılmıştır. Sertleşmiş beton özelliklerini belirlemek için su emme, kuru birim ağırlık testi, basınç dayanımı testi, yarmada çekme dayanımı testleri uygulanmıştır. Çalışma sonucunda; %15 mermer tozu kullanımının uygun olacağı kendiliğinden yerleşen hafif beton üretiminde kullanılmasında bir sakınca olmadığı belirlenmiştir. Mermer tozu gibi endüstriyel atıkların beton üretiminde kullanılması hem çevre kirliliği hem de sürdürülebilirlik açısından önemlidir.
AtıfOpenAlex2
İncele - MakaleAçık Erişim2022Forecasting of Export Volume Using Artificial Intelligence Based Algorithms
Ozden, Erdemalp
Technological breakthroughs have transformed communication and taken transportation, health, and commerce to an unprecedented level. In this way, sudden developments have rapidly affected all countries. In this context, analysis methods are changing compared to the past, and annual analyses fail to catch the trend even for macroeconomic indicators. In this paper, new artificial intelligence-based estimation methods were used to see the future trend of export volume, and their estimation performances were compared by adding them to the classical econometric method. Historical quarterly data from 2013 to 2021 were used in the training and testing phases of the models. For this purpose, the variables of gross domestic product, foreign direct investment, and dollar exchange rate, which affect the export volume, were determined as inputs in estimating the export volume. According to the analysis results, support vector machine model was determined as the best method for predicting export volume in Turkey. This study can provide an essential basis for policymakers to export estimation and formulate their export-enhancing policies effectively.
- MakaleAçık Erişim2022Scopus SJRQ3Turkey's Long-Term Electricity Consumption Forecast
Emec, S.; Akkaya, G.
Demand forecasting is essential primarily for planning. Although it is crucial in many sectors and issues, it has particular importance for electricity. Therefore, the issue of electricity consumption forecasting has recently become a prevalent topic. In light of the above, this study aimed to develop an appropriate model to estimate the long-term electricity consumption of Turkey. The study consists of three steps. In the first step, eight models were developed to separately investigate the effects of eight input variables frequently used in electricity consumption forecasting studies in the literature. In the second step of the study, two models consisting of input variables with high impact in the first step were developed, and the trained performances of the developed models were calculated by using the regression analysis. In the final step, the combined effect of eight variables on electricity consumption forecasting was investigated using regression analysis. It can be conclude that the model in the third step showed significant results, and the model performance was good. Finally, Turkey's electricity consumption forecast for the years 2020-2030 was performed using the model in the third step.
AtıfWoS1OpenAlex3İncele - MakaleYalnız künye2022Scopus SJRQ1Nondestructive Experimental Measurement, Model Updating, and Fatigue Life Assessment of carsamba Suspension Bridge
Günaydin, Murat; Sunca, Fezayil; Altunisik, Ahmet Can; Ergün, Mustafa; Okur, Fatih Yesevi
This paper includes the structural condition assessment of a 164-m suspension bridge in accordance with numerical and experimental methods. A finite-element model was developed using SAP2000 software so that the assessment of the bridge could be calculated numerically. The operational modal analysis method was also used to obtain experimental dynamic characteristics. In this context: (i) numerical dynamic characteristics of the bridge were obtained and compared with the experimental dynamic characteristics, (ii) a model updating procedure was carried out to minimize the differences between the numerical and experimental natural frequencies, (iii) static and dynamic analyses of the bridge were carried out by using the initial and updated finite-element models, (iv) fatigue life assessment of the bridge was investigated, and (v) the utility of the bridge for pedestrians and vehicles was checked according to various regulations. The results showed that updating the finite-element model had a significant role to play in the static and dynamic behavior of the bridge. The results also demonstrated that the bridge was designed to be extremely safe against static, dynamic, and fatigue loads. Finally, it was concluded that the bridge investigated behaves as a girder bridge rather than a suspension bridge.
AtıfWoS17OpenAlex18İncele - MakaleAçık Erişim2022Scopus SJRQ1Structural Investigation of Masonry Arch Bridges Using Various Nonlinear Finite-Element Models
Tapkin, Serkan; Tercan, Emre; Motsa, Siphesihle Mpho; Drosopoulos, Georgios; Stavroulaki, Maria; Maravelakis, Emmanuel; Stavroulakis, Georgios
This article presents an investigation of the structural behavior of a masonry arch bridge in Turkey. An analytical study has been conducted to provide the geometry of the structure, using laser scanning. A point cloud describing the geometry was obtained and properly transformed into a format that is appropriate for structural analysis software (CAE). Then, nonlinear finite-element models were developed to simulate structural responses of the bridge. The goal of the article is to highlight the influence of both continuum and discrete approaches and related constitutive laws on the responses of the bridge. Thus, continuum damage laws and a discrete model consisting of unilateral contact-friction interfaces were developed. Different load cases were tested and a comparison between the results obtained from the different approaches was considered. The failure mechanisms and the ultimate strengths were derived, and core points of the models were highlighted. The output of this work shows how the different failure models predict the behavior of the masonry arches. It also shows that the three-hinge mechanism, which has been depicted in classical studies for single-span arch masonry bridges under a horizontal settlement of supports, may also be obtained for multiarch bridges. Similarly, downward, vertical settlement of supports may result in the development of two hinges, as in single-span arches. Finally, the beneficial influence of the backfill in limiting the failure in the arch is addressed.
AtıfWoS18OpenAlex21İncele - MakaleAçık Erişim2022Scopus SJRQ1Conventional and Microcellular Injection Molding of a Highly Filled Polycarbonate Composite with Glass Fibers and Carbon Black
Yilmaz, Galip; Devahastin, Apichart; Turng, Lih-Sheng
Conventional solid injection molding (CIM) and microcellular injection molding (MIM) of a highly filled polycarbonate (PC) composite with glass fibers and carbon black were performed for molding ASTM tensile test bars and a box-shape part with variable wall thickness. A scanning electron microscope (SEM) was used to examine the microstructure at the fractured surface of the tensile test bar samples. The fine and uniform cellular structure suggests that the PC composite is a suitable material for foaming applications. Standard tensile tests showed that, while the ultimate strength and elongation at break were lower for the foamed test bars at 4.0–11.4% weight reduction, their specific Young’s modulus was comparable to that of their solid counterparts. A melt flow and transition model was proposed to explain the unique, irregular “tiger-stripes” exhibited on the surface of solid test bars. Increasing the supercritical fluid (SCF) dosage and weight reduction of foamed samples resulted in swirl marks on the part surface, making the tiger-stripes less noticeable. Finally, it was found that an injection pressure reduction of 25.8% could be achieved with MIM for molding a complex box-shaped part in a consistent and reliable fashion.
AtıfScopus2WoS2OpenAlex3İncele - BildiriYalnız künye2022Evaluating Path Selection Strategies with Blockchain-based Routing in Multi-Domain SDNs
Guler, Evrim; Karakus, Murat; Uludag, Suleyman
Software-Defined Networking (SDN) has emerged as one of the most prolific inventions in the general area of computer communications over the past decade. Among many of the touted benefits, SDN architecture facilitated by OpenFlow has the potential to help network administrators to provide End-to-End (E2E) Quality of Service (QoS)-guaranteed paths for flows among networks while providing finer-granular flow management along with global network view. In our previous work, we have introduced QoSChain to amalgamate the advantages of blockchain and SDN for inter-network QoS provisioning to orchestrate an agile and software-driven traffic management framework in order to facilitate cross-network policy automation, assurance, E2E visibility, control and validation. In this study, we focus on the impact of the path selection strategies on the performance of the overall QoSChain performance. Specifically, we exploit three simple but effective path selection strategies, First Feasible Path Selection (FFPS), Random Feasible Path Selection (RFPS), and Minimum Hop Path Selection (MHPS), to evaluate their performance, impact, and overhead in terms of the flow setup time, message overhead, and network resource consumption metrics. Our preliminary simulations results show that the path selection plays an important role in the overall performance with hop count minimization delivering a superior performance offset by an initial higher setup times.
AtıfScopus7OpenAlex9İncele - MakaleYalnız künye2022Scopus SJRQ1Seismic behavior assessment of historical Alaeddin Bey Mosque and strengthening suggestions by CFRP fabric and steel plate
Şentürk, İdris; Ergün, Mustafa; Artar, Musa
In this study, the effects of different strengthening methods that can be applied for earthquake-damaged historical masonry structures on structural performance were investigated. For this purpose, the Historical Alaeddin Bey Mosque in the central district of Muş was modeled in three dimensions according to the macromodeling technique using the finite element method in the SAP2000 program. The earthquake performance of the structure was determined by considering the earthquake-acceleration records of Erzincan, Kocaeli, and Van, respectively. The maximum tensile and compressive stresses in all three directions on the structural elements were taken into account as the earthquake behavior parameters of the structure. According to the earthquake analysis made in the time domain, it was determined that the polygonal pulpit of the minaret was at risk of being damaged under the effect of the Erzincan earthquake, and it has been concluded that this region should be strengthened. The damaged area of the minaret was strengthened by the application of CFRP fabric and steel plate materials (together or separately) in five different ways, from inside and outside and at different distance intervals. The conclusions obtained as a result of the earthquake analyses on the reinforced models were examined, and it was explained in detail with the help of tables and graphics that method would be more effective in strengthening such damages.
AtıfScopus40WoS39OpenAlex41İncele
