Yazarlar
- Can, Erol(29)
- Kumbasaroglu, Atila(17)
- Yalciner, Hakan(17)
- Bayata, Halim Ferit(14)
- Ting, Naim Suleyman(14)
- Katipoğlu, Okan Mert(13)
- Bayrak, Osman Ünsal(12)
- Sahin, Yakup(12)
- Turan, Ahmet İhsan(9)
- Baş, Fatih İrfan(8)
- Destek, Mehmet Akif(8)
- Manga, Müge(8)
- Çolak, Muhammed Ali(8)
- Bulut, H. Alperen(6)
- Manga, Muge(6)
- Tastimur, Canan(6)
- Akin, Erhan(5)
- Akoğuz, Harun(5)
- Akın, Fatih(5)
- Balli, Esra(5)
- Dede, Tayfun(5)
- Sarıgöl, Metin(5)
- Sarıçiçek, İnci(5)
- Aka, Salih(4)
- Ayasun, Saffet(4)
- Ayaz, Yaşar(4)
- Celik, Alper(4)
- Demirci, Oğuz Kürşat(4)
- Demirel, Soner(4)
- Kalkan, Orhan(4)
- Keleş, Ömer Faruk(4)
- Tortum, Ahmet(4)
- Tuysuz, Suat(4)
- Yavuz, Selahattin(4)
- Yazici, Ahmet(4)
- Yazıcı, Ahmet(4)
- Yesilyurt, Huseyin(4)
- Yılmaz, Mehmet(4)
- Çabuk, Umut Can(4)
- Özkan, Kemal(4)
Yayınlar
- ArticleYalnız künye2025Vibration characteristics of a cracked multi-bay frame with moving oscillatory loads
Demirtaş, Salih; Ozturk, Hasan; Kiral, Zeki
This research focuses on analyzing the resonance behavior of a cracked multi-bay frame structure under the influence of moving oscillatory loads, specifically examining vibrations in both axial and vertical directions. To model the system, the finite element approach, integrated with Lagrange’s formulation, was applied, utilizing the Bernoulli-Euler beam assumptions to derive the in-plane motion equations. The dynamic structural response was calculated using the Newmark integration algorithm. For damaged elements, stiffness characteristics were formulated based on principles from fracture mechanics. A three-dimensional graph showing the interdependence of crack position, oscillator speed, and peak displacement was developed to visualize the effect of crack location. The findings revealed that the initial resonant frequency corresponds to the first vibrational mode, which is predominantly horizontal, while the second resonant condition aligns with vertical mode dominance.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025A transformer-based deep reinforcement learning for the Dial-a-Ride problem
Aslan Yıldız, Özge; Sarıçiçek, İnci; Yazıcı, Ahmet
Dial-a-Ride problem (DARP) is a specialized variant of the vehicle routing problem that focuses on designing optimal routes for users who specify pick-up and delivery requests between origins and destinations. This problem involves determining the most effective and efficient routes using limited vehicles and resources to offer responsive door-to-door transportation services for users with specific needs. Logistics service providers require systems that can deliver optimal solutions to these combinatorial problems within a reasonable time. Recently, there has been a significant increase in the use of artificial intelligence optimization algorithms such as meta-heuristics or learning-based approaches to solve such problems. Among the learning-based approaches, reinforcement learning has gained prominence for routing and scheduling tasks, owing to its ability to adaptively learn from complex state spaces and dynamically changing environments. In this study, a novel transformer-based deep reinforcement learning method is proposed to solve the Dial and Ride problem for a single service vehicle. In the proposed model, we adopt a modified transformer architecture instead of employing traditional linear layers, we integrate convolutional layers. To validate our approach, we conduct comprehensive experiments comparing our method against four well-known metaheuristic algorithms and a Deep Q-Network algorithm. The results indicate that proposed approach outperforms these techniques in terms of shorter total travel distances. Additionally, the proposed method is tested on a real-world scenario generated in the Buyukdere neighborhood of Eskisehir. The results demonstrate that the proposed method makes it possible to solve the problem within a reasonable time. This study confirms that the proposed deep reinforcement learning method can effectively address the Dial-a-Ride Problems.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Prediction of seismic performance levels of corroded RC frames based on crack width
Turan, Ahmet İhsan; Kumbasaroglu, Atila; Yalciner, Hakan; Ayaz, Yaşar
In reinforced concrete (RC) structures, corrosion of the reinforcement due to environmental factors or concrete components poses significant risks to both structural integrity and safety. Reinforcement corrosion, can be visually detected through cracks in the concrete cover, and this situation offers a practical approach to associating corrosion-induced cracks with structural parameter degradations caused by the corrosion mechanism. In this study, a total of five RC frame specimens were fabricated, with one specimen not exposed to corrosion and four specimens exposed to different levels of corrosion through the accelerated corrosion method, all having the same cross-section and material properties. In the experiments conducted under a constant 20 % axial load and cyclic repeated load effects, the structural performance indicators of the RC frame specimens were examined. Within the scope of the study, two experimental models are proposed. The first model aims to estimate the loss in the cross-sectional area of the reinforcement bar based on crack width, while the second model was oriented towards estimating the energy consumption capacity of the specimen for a specific displacement ratio based on the loss in the cross-sectional area of the reinforcement. The results revealed that as the corrosion ratio increased, the crack widths of the specimens also increased, and after a 1.5 % drift ratio, there was a significant decrease in the energy consumption capacities of the corroded specimens.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2025Predicting air quality index in başakşehir, istanbul with hybrid ai models: unveiling key drivers through catboost-based shap and feature importance analysis
Akiner, Muhammed Ernur; Katipoğlu, Okan Mert; Çintaş, Emre
Urban air quality influences public health, ecosystem sustainability and economic productivity. This study focuses on predicting the Air Quality Index (AQI) in Başakşehir, Istanbul. The study proposes a hybrid artificial intelligence (AI) model that amalgamates Categorical Boosting (CatBoost), Shapley Additive Explanations (SHAP) and the feature importance analysis. The dataset encompasses various meteorological parameters, including Tempmax, Tempmin, Temp, Dew, Humidity, Precip, Windspeed, Sea level pressure, Cloud cover, Solar radiation, Solar energy and UV index, in addition to air quality parameters such as PM10, SO2, CO, NO2, NOX, NO and O3. These variables serve as inputs for models like ANN, BAT-ANN,- BBO-ANN, GWO-ANN, HCA-ANN, CatBoost and CNN; the intent is to enhance the accuracy of the AQI prediction. When the combined set of variables were employed as inputs, the most precise results emerged from the CNN model, which yielded an RMSE of 1.43, an AIC of 949.21 and an NSE and R2 of 0.99. The CatBoost model exhibited exceptional performance among the various input combinations, providing the most accurate results for these configurations. Non-parametric statistical Friedman and Nemenyi post-hoc tests were used for multi-model comparison, and it was concluded that there were significant performance differences between the models used according to the p-value values, both in general and based on pairs. While prior studies have explored hybrid AI models for AQI prediction, this study uniquely integrates CatBoost and SHAP for enhanced explainability and model performance evaluation. SHAP analysis provided transparent insights into variable contributions; however, PM10 emerged as the dominant predictor, achieving the highest mutual information score of 6.88. These findings underscore the importance of integrating pollutant and meteorological data. The proposed methodology aligns with global sustainability goals, including SDG 11 (Sustainable Cities and Communities) and SDG 13 (Climate Action).
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Integrated Emission and Cost Analysis of Battery-Electric Vehicles up to 2035
Demirci, Oğuz Kürşat
This study quantifies when battery-electric vehicles (BEVs) reach total cost of ownership (TCO) parity with their internal-com-bustion counterparts and characterises the cradle-to-grave greenhouse-gas (GHG) intensity trajectory to 2035. Our contribution is a transparent, Python-based framework that integrates battery-cost learning, ownership economics and life-cycle impacts within a harmonised scenario set, and links them to policy timing, ISO 15118-20-ready bidirectional charging and power-system carbon intensity. Drawing on a systematic synthesis of 221 peer-reviewed sources (2013–2025), the model runs annually for a representa-tive C-segment BEV across three scenarios (Reference, Fast-Progress, Slow-Progress; 2024–2035). The results indicate that, under the median battery-pack price learning trajectory, BEV TCO falls below the ICE benchmark around 2029 (2028–2032 across sce-narios), while life-cycle GHG intensity declines from approximately 73 to 34 g CO2-eq km-1 by 2035, spanning 29–42 g km-1 depending on grid decarbonisation. Global sensitivity analysis identifies battery price as the principal driver of TCO outcomes and grid carbon intensity as the principal driver of emissions outcomes. Results are reported for three regional aggregates (OECD average, EU-27 and China), and the policy discussion highlights contrasts for the United States to contextualise cross-market dif-ferences. Policy alignment on three fronts—parity-linked purchase-incentive phase-outs, rapid deployment of ISO 15118-20-ready bidirectional charging, and stronger recycled-content targets—shortens time to cost competitiveness and amplifies the climate ben-efits of large-scale electrification.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Is Erzincan, Located on the North Anatolian Fault Zone, Which Produced the Biggest Earthquake in Turkey and the World, Ready for the Next Severe Earthquake?
Ulusu, İsmet
The main causes of damage include poor site selection, such as building on fault lines or on fill soil, as well as deficiencies in design, materials, and workmanship. Damage levels are also linked to the economic conditions of the region. In the 1939 earthquake, there were high casualties due to the magnitude of the earthquake, lack of engineering design in traditional structures and unsuitable soil conditions. Similarly, in the 1992 earthquake, unexpected damage occurred due to faulty designs created by inexperienced engineers who lacked sufficient knowledge of the seismic behavior of structures, errors in craftsmanship and workmanship, and unsuitable residential area selection for construction. These problems continue today and put most of the building stock at risk in case of a major earthquake. Seismic steel isolators are used in two new buildings in the city; if they are effective, they should be made mandatory in new construction. Otherwise, consideration should be given to relocating the city to the more stable southern rocky areas, which were unaffected in both 1939 and 1992.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2025Fully Insulated Dual Output DC-DC Converter Battery Charging System with Single Dynamo Input at the Electric Vehicle
Can, Erol; Kürşat Demirci, Oğuz
Battery charging and regulation for the electrical system of electric cars or fuel cars are of great importance for the efficient operation and comfort of the vehicles. In this study, a DC-DC boost converter system that can charge two batteries isolated from each other with the same dynamo for a car is presented. With this system, it is possible to charge two different batteries at their nominal voltages at the same time by increasing the voltage of the system at the low voltage inputs that will occur. First, the circuit model and mathematical expansions that give the operating logic of the circuit are given. Then, the designed circuit model is operated between the modulation indexes of 0.2-0.5 and two different batteries are fed at their nominal voltages in isolation from each other. After the simulation studies, the current and voltage values of the circuit elements and the charging parameters of the battery are measured and the system application is carried out. According to the obtained results, although the charging circuit receives low voltage from the alternator, the two batteries can be charged to the requested level with the proposed system.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Bist100 İmalat İşletmelerinin Malmquist Toplam Faktör Verimlilik Endeksi ile Analizi
Yavuz, Selahattin; Yaşar, Feyzi
Bu çalışmada, Borsa İstanbul BİST 100’de işlem gören imalat işletmelerinin toplam faktör verimlilikleri, Malmquist toplam faktör verimlilik (MTFV) endeksi ile ölçülmüştür. 2010-2017 yıllarını kapsayan çalışma döneminde 37 işletmeye ait cari oran, aktif devir hızı, alacak devir hızı, stok devir hızı, finansal kaldıraç oranı, uzun vadeli borçlar/özsermaye oranı ve duran varlıklar/ devamlı sermaye oranı girdi değişkenleri olarak; net kâr marjı, faaliyet kâr marjı, özsermaye kârlılığı ve aktif kârlılık oranı da çıktı değişkenleri olarak kullanılmıştır. Elde edilen sonuçlara göre imalat işletmelerinin ortalama toplam faktör verimlilik değerleri, 2012-2013 ve 2016-2017 dönemlerinde azalış, diğer dönemlerde ise artış göstermiştir. İşletmelerin en etkin çalıştıkları dönem 2013-2014 dönemi olmuştur. Malmquist toplam faktör verimliliği endeksine göre imalat işletmeleri 2010-2017 döneminde yıllık ortalama %26,9 verimlilik artışı göstermiştir. İşletmelerin bu verimlilik artışı, teknik etkinlikteki artıştan ve teknolojik ilerlemeden kaynaklanmıştır. İşletme bazında yapılan değerlendirmede verimlilik artışı en yüksek olan KARSN (%221,1), GEREL (%79,1) ve AFYON (%64,0) işletmelerinin ilk üç sırayı aldığı tespit edilmiştir.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Investigation of Freeze-Thaw Properties of High Plasticity Clay Soil Improved with Lime and Sodium Alginate Biopolymer
Akoğuz, Harun; Teber, Dilber
In this study, the effect of sodium alginate biopolymer and the effectiveness of sodium alginate biopolymer combined with lime in improving a high-plasticity clay soil were investigated. For this purpose, 0%, 0.5%, 1%, and 1.5% biopolymers and 0%, 2%, 4%, and 6% lime were added to the clay soil. At the end of the 7 and 28 day curing period, the strength results were evaluated with unconfined compressive strength tests. In order to examine the effects of environmental factors, the improved soil samples were exposed to freeze-thaw cycles for 5 and 10 cycles. As a result, it was observed that sodium alginate biopolymers had higher unconfined compressive strengths compared to pure samples at the end of the curing periods. As a result of freeze-thaw cycles, it was determined that the biopolymer additive improved the strength results. When using biopolymer with lime, it was determined as a result of strength tests and freeze-thaw cycles that biopolymer increased the effectiveness of lime in soil improvement. As a result, it has been evaluated that sodium alginate, an environmentally friendly biopolymer, may have positive contributions to engineering applications in the improvement of clay soils.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Estimating contract value using structural parameters: a machine learning approach with data preprocessing
Aslay, Semi Emrah
In this study, contract price in public construction tenders are predicted using structural project parameters. The variables applied in the study are created by adding the quantities of columns, shear walls, and beams to variables commonly used in the literature for cost estimations. Six different machine learning algorithms are employed as machine learning algorithms. Preprocessing methods and a series of parameter optimizations are applied to enhance the predictive capability on datasets. These processes and the applied algorithms are evaluated with five different performance metrics. The SVM algorithm produced the best results, achieving an value of 0.8966, MAPE of 23.70, NSE of 0.8956, MAE of 0.4849, and RMSE of 0.6989. This study contributes to the literature by developing machine learning models and data analysis processes for contract price approaches.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Endüstri 4.0 ve Çevresel Sürdürülebilirlik Arasındaki İlişki: Avrupa Birliği Ülkeleri Üzerine Ampirik Bir Analiz
Akın, Fatih; Dinçer, Selin
Endüstri 4.0 olarak bilinen dördüncü sanayi devrimi ve beraberinde getirdiği dijital dönüşüm tüm dünyada her geçen gün etkisini artırmaktadır. Bu eksende Endüstri 4.0 ile yaşanan dijital değişim bireylerin yaşamlarında ve çalışma hayatlarında köklü değişimleri beraberinde getirmektedir. Bireylerin yanı sıra çeşitli endüstrilerin üretim süreçlerinin iyileştirilmesinde de Endüstri 4.0 oldukça dikkat çekmektedir. Diğer taraftan 18. yüzyılda Sanayi Devrimi ile başlayan olumsuz çevresel etkilerin yanı sıra sürekli artan tüketim talebini karşılamak için kullanılan ve tükenmekte olan doğal kaynaklar ülkeleri harekete geçirmektedir. Avrupa Birliği ülkelerinde de Endüstri 4.0 ile ilişkili teknolojilerin benimsenmesini teşvik etmek amacıyla politikalar uygulandığı bilinmektedir. Bu anlamda Endüstri 4.0'ın sürdürülebilir ekonomik büyüme, kalkınma ve çevreye katkı sağlayabileceği fikri gündeme gelmektedir. Bu çalışma Avrupa Birliği’ne üye 27 ülkede Endüstri 4.0 ve çevresel sürdürülebilirlik arasındaki kısa ve uzun dönemli ilişkiyi araştırmayı amaçlamaktadır. Bu amaçtan yola çıkarak çalışmada, 1996-2020 dönemi için panel ARDL/PMG analiz yöntemi kullanılarak çevreyi temsilen ekolojik ayak izi, Endüstri 4.0’ı temsilen ise teknoloji patenti değişkenleri kullanılmıştır. Ayrıca ekonomik büyüme ve enerji tüketimi değişkenleri kontrol değişken olarak kullanılmıştır. Bulgular, Avrupa Birliği ülkelerinde uzun dönemde patent sayısındaki artışın ekolojik ayak izini azalttığını ortaya koymaktadır. Diğer taraftan çalışmada, Avrupa Birliği ülkelerinde ekonomik büyüme ve enerji tüketiminin ekolojik ayak izini artırdığı tespit edilmiştir. Çalışma bulguları, Avrupa Birliği ülkelerinde Endüstri 4.0 teknolojilerinin sürdürülebilir çevre üzerinde önemli etkisinin bulunduğunu ortaya koymaktadır.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Drone selection for agricultural enterprises with interval TYPE-2 fuzzy copras method
Oğuz, Alparslan
Technological advancements have led to changes in unmanned aerial vehicles, just as in all fields. These vehicles, known as drones, are used in many areas such as mapping, logistics, entertainment, and agriculture. Especially in agriculture, drones are widely used for various purposes such as mapping, detecting weeds, fertilization, and spraying. This situation has increased the market volume of drones and many companies have introduced their products for sale. Agriculture plays a significant role in the development of developing countries, and drone technologies are of great importance in increasing sector productivity. Drone technologies provide transparency and traceability in the cultivation process of products. Therefore, the aim of the study is to determine the selection criteria of agricultural drones for agricultural enterprises and to select the most suitable alternative among the alternatives. Nine criteria were determined through literature review and expert opinion. Seven alternatives from two companies selling in Türkiye were evaluated. Alternatives were analyzed using the Interval Type-2 COPRAS method. As a result of the evaluation by three experts, alternative A2 was determined as the most suitable alternative.
RDL Kalıcı Kaydıİncele - Conference ObjectYalnız künye2024Traffic Light Control with Policy Gradient-Based Reinforcement Learning
Tas, Mehmet Bilge Han; Özkan, Kemal; Sariçiçek, Inci; Yazici, Ahmet
With the increase in population and transportation vehicles, increasing transportation times due to traffic density and carbon dioxide emitted by vehicles is one of the most important problems today. In this study, it is aimed to reduce these times and reduce traffic density by controlling traffic lights within the scope of smart cities. By using Policy Gradient-based reinforcement learning, a realistic city traffic sample is created with various vehicle elements such as cars, motorcycles and bicycles, and traffic lights are controlled to provide a smoother traffic with lower transportation times. Thanks to the application, a one-third improvement was achieved in the 180-hour period presented as an example.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024In pursuit of increasing supply chain innovation performance through suppliers' promotive voice: the moderating role of unlearning and transparency
Polater, Abdussamet
In today's dynamic business environment, leveraging innovative supply chain (SC) solutions is critical for increasing competitive advantage. While numerous studies have considered the potential of SC innovation (SCI) in the face of growing new problems and challenges, not much is known about the effect of suppliers' promotive voice behavior (PVB) in this process. This study extends the current research on SCI by investigating the underlying mechanisms by which firms exploit the suggestions and ideas they gain from SC interactions. Building on the relational view (RV) we develop hypotheses that identify the effect of suppliers' PVB as an important mediator in the relationship between incentives and SCI. Further, we suggest that incentives and two contextual factors (i.e., unlearning reputation and transparency) interact to predict SCI through suppliers' PVB. For the purpose of testing the proposed hypothesis a survey was administrated to managers involved in SC relationships. The analysis provides the evidence that suppliers' PVB has a positive influence on SCI. In addition, the association between incentives and SCI was empirically demonstrated to be mediated by suppliers' PVB. Furthermore, it was determined that incentive's effect on SCI through suppliers' PVB was conditional such that unlearning reputation's effect depended on transparency. In this regard, this study extends the discussion of factors that influence SCI and provides some theoretical and managerial contributions by examining the interplay between incentives, transparency, and unlearning reputation on the suppliers' PVB and SCI.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Geotechnical and Structural Damages Caused by the 2023 Kahramanmaraş Earthquakes in Gölbaşı (Adıyaman)
Akar, Fahriye; Işık, Ercan; Avcil, Fatih; Büyüksaraç, Aydın; Arkan, Enes; İzol, Rabia
On 6 February 2023, two independent earthquake pairs on the East Anatolian Fault Zone, with epicenters in Pazarcık (Mw = 7.7) and Elbistan (Mw = 7.6) districts of Kahramanmaraş province, caused great destruction. Adıyaman and Gölbaşı districts of this city are among the settlements most affected by the earthquake. Especially in the district where geotechnical damages are most observed, the destructive effects of earthquakes have been clearly observed in buildings with different structural systems. In this study, information is given about the earthquakes that hit the region and the fault zone where the earthquakes occur. Geotechnical and structural damages occurring in the villages and center of the district were evaluated within the scope of earthquakes and structural engineering. It can be stated that damages observed in the district center are generally caused by soil–structure interaction problems. The fact that masonry structures, which are widely used in rural areas, do not benefit from any engineering services has an impact on the level of damage. The main reason for the damages occurring in the reinforced concrete structures in the district is the reinforced concrete system that is not designed properly or not built in accordance with the design. This case study demonstrated the importance of earthquake–soil–structure interactions in line with earthquake-resistant building design principles.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Impact of virtual inertia and damping control on stability delay margins of load frequency control systems with renewable energy sources
Hasen, Suud Ademnur; Aydın, Ömer; Ayasun, Saffet; Sönmez, Şahin
The utilization of communication linkages generates delays that degrade system dynamic performance and cause fluctuations in the system frequency while the extensive integration of renewable energy sources may cause further increase in the frequency oscillations owing to low inertia. By considering the inclusion of the virtual inertia and damping (VID) control in load frequency control (LFC) systems with time delays, this article investigates the impacts of the VID control on the stability delay margins (SDMs) of two-area LFC systems. For this purpose, an exact method, which is based on recursively removing exponential terms from the characteristic equation, is first implemented to compute SDMs of the two-area LFC system enhanced by VID control for a wide range of controller gains. Secondly, the effect of the VID parameters on the SDMs is investigated by employing the exact method. Theoretical results clearly illustrate that SDMs significantly increase as VID parameters increase. Furthermore, simulation analysis elucidates that with the VID incorporation, the performance of the LFC system with low inertia is enhanced and the rate of change of the frequency and frequency nadir are remarkably decreased, improving the stability of time-delayed LFC systems.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024PID Control of Hybrid DC-DC Converter System in Complex Load with Double Reference Time
Can, Erol; Gülnahar, Murat
DC-DC converters are circuits that are widely used in energy distribution systems, in industry and technology applications, as well as in household appliances such as computers and televisions, and in uninterruptible power supplies used to feed all these systems. For the design and optimization of DC-DC converter circuits, it is important to create and analyze mathematical models according to the load it is connected to. Simple load structures and circuit structures have been examined and control units have been designed in studies carried out to date. In this study, while the DC-DC converter with a more complex load structure is discussed, mathematical analysis and PID control of DC-DC converters with Buck-Boost feature are performed with the same modulation index in different time periods. In the results obtained, it is shown how to create the mathematical models of a system that provides DC-DC energy conversion with a complex load structure and how to formulate the PID control in a system with this complex load structure.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Indoor Localization With an Autoencoder-Based Convolutional Neural Network
Arslantas, Hatice; Okdem, Selcuk
Nowadays, studies on indoor localization systems based on wireless systems are increasing widely. Indoor localization is the process of determining the location of objects or people inside a building. Global Navigation Satellite System (GPS) signals do not provide sufficient location data indoors because they are interrupted or completely lost in closed areas. For this reason, studies on indoor localization system design with machine learning and deep learning techniques based on Wi-Fi technology are increasing. In this study, we propose a method and training strategy that is entirely based on a Convolutional Neural Network (CNN) and a combined autoencoder that automatically extracts features from Wi-Fi fingerprint samples. In this model, we coupled an autoencoder and a CNN and we trained them simultaneously. Thus, we guarantee that the encoder and the CNN are trained simultaneously. The proposed system was evaluated on the UJIIndoorLoc and Tampere datasets. The experimental results show that the proposed model performs significantly better than the current state-of-the-art methods in terms of location coordinates (x, y) localization. In our study, runtime analysis is also presented to show the real-time performance of the network we proposed.
RDL Kalıcı Kaydıİncele - ArticleAçık Erişim2024Comparative Analysis of OECD Countries in Terms of Basic Science and Technology Indicators Using Entropy and WASPAS Methods
Yavuz, Selahattin; Manga, Müge
Practical analysis of the policies implemented by countries successful in the field of science and technology is crucial, especially in the context of optimal policy selection for countries needing technological development. In this context, ranking the world’s countries in terms of technological development is important for increasing the effectiveness of the policies to be implemented in this field. This study ranks 28 OECD countries on seven key science and technology indicators in 2022 using multi-criteria decision making (MCDM) methods. In the analysis, first, the importance of the variables was ranked based on the entropy method. Then, a ranking was made among the selected countries in terms of technological performance using the weighted aggregated sum product assessment (WASPAS) method. The findings obtained with the WASPAS method were confirmed with the additive ratio assessment (ARAS) method. Among the identified variables, the export market (share of computer, electronics and optics sector) parameter was selected as the most dominant criterion. Korea, Germany, Japan, France and the Netherlands were determined to be the best performing in terms of basic science and technology indicators. On the other hand, it can be said that Chile, Latvia, Luxembourg and Lithuania need more effective policies in terms of technology and innovation indicators. In this context, it can be suggested that the policies implemented by countries at the forefront in technological development should be a guide for other countries.
RDL Kalıcı Kaydıİncele - ArticleYalnız künye2024Experimental investigation on mechanical properties of sustainable roller compacted concrete pavement (RCCP) containing waste rubbers as alternative aggregates
Keleş, Ömer Faruk; Bayrak, Osman Ünsal; Bayata, Halim Ferit
Different types of solid waste are generated every year due to global industrialization. With the rapid growth of the automobile industry, the disposal of billions of waste rubbers (WR), which pollute the environment and cannot be disposed of properly, is emerging as an urgent matter of concern. Recycling waste rubbers by using them on pavements will contribute to the elimination of ecological and economic problems. In this study, the effects of waste rubbers on the mechanical properties of roller-compacted concrete pavement (RCCP) were investigated by obtaining sustainable RCCP mixtures using different types of waste rubbers as coarse and fine aggregate substitutes. In this context, waste rubbers with three different sizes (powder, crumb and shredded) were substituted for aggregate by volume at seven levels (0%, 2.5%, 5%, 7.5%, 10%, 20% and 30%) with a maximum of 30% in RCC mixtures. Unit weight, mechanical properties, modulus of elasticity and ultrasonic pulse velocity (UPV) were evaluated and compared according to the waste rubber content in the RCC mixtures. In addition, microstructural analysis of the mixtures was performed through scanning electron microscopy (SEM). The experimental results revealed that the compressive, flexural and splitting tensile strength and modulus of elasticity decreased with increasing waste rubber content in RCC. The utilization of waste rubber increased the ductility of RCC and decreased the density to produce lighter concrete. RCC with a compressive strength of about 30 MPa could be obtained by substituting 10% of waste rubber for aggregate. Thus, the utilization of high waste rubber content in pavements was feasible. This study can contribute to a more sustainable RCCP production by replacing natural aggregates with waste rubbers.
RDL Kalıcı Kaydıİncele
