Improving the performance of the population-based metaheuristic equilibrium optimizer algorithm

Equilibrium Optimizasyon (EO) algoritması, bir kontrol hacmindeki giren, üretilen ve çıkan maddelerin dengesini açıklayan kütle dengesi yasasından esinlenmiş, fizik tabanlı bir optimizasyon algoritmasıdır. Equilibrium Optimizasyonu literatürde kabul görmüş ve başarılı bir algoritma olmasına karşın, performansı ile ilgili bazı zayıf ve eksik yönleri bulunmaktadır. Başlıca sorunları arasında düşük yakınsama kabiliyeti, yerel minimumlara takılma ve keşif ile sömürü evreleri arasındaki dengesizlik bulunmaktadır. Bu tez çalışmasında, Equilibrium Optimizasyon (EO) algoritmasının performansını artırmayı ve mevcut eksikliklerini gidermeyi hedefleyen iki yeni algoritma önerilmektedir. Önerilen ilk algoritma, Güçlendirilmiş Equilibrium Optimizasyon (BEO) algoritmasıdır. Sunulan algoritma, başlangıç popülasyonu, aday havuzunun oluşturulması ve güncellenmesi aşamaları için yeni yöntemler sunmaktadır. Önerilen algoritmada geleneksel rastgele başlangıç popülasyonu yerine düzgün dağılımlı rastgele başlangıç popülasyonu ve ortalama tabanlı konsantrasyon havuzu stratejisi kullanılarak keşif aşaması güçlendirilmiştir. Ayrıca, güncelleme aşaması için önerilen iki yeni yaklaşım ile keşif ve sömürü aşamaları arasındaki dengenin daha kararlı bir şekilde sağlanması hedeflenmektedir. Önerilen ikinci algoritma, EO algoritmasının güncelleme mekanizması için yeni bir strateji sunmaktadır. Mevcut Equilibrium Optimizasyon algoritmasında, arama ajanları bireysel başarı durumları dikkate alınmaksızın topluca güncellenmekte, bu da özellikle çok modlu optimizasyon problemlerinde optimum çözüme ulaşmayı zorlaştırmaktadır. Önerilen Parçacık Güncelleme Tabanlı Equilibrium Optimizasyon Algoritması (PUBEO), sunduğu strateji ile arama ajanlarını bireysel olarak değerlendirip güncelleyerek bu sorunu aşmayı hedeflemektedir. Algoritmaların performans testleri için ilk olarak tek modlu, çok modlu ve sabit boyutlu çok modlu, toplam 23 adet klasik test fonksiyonu içeren bir test seti kullanılmıştır. BEO algoritmasının performans testleri, öncelikle EO ve geliştirilen varyant algoritmalar arasında, ardından literatürde kabul gören diğer bazı algoritmalar arasında gerçekleştirilmiştir. PUBEO algoritmasının performansını değerlendirmek amacıyla, klasik test problemlerine ek olarak 29 fonksiyondan oluşan CEC-2017 test seti kullanılmıştır. Ayrıca, önerilen her iki algoritma, bu testlerin yanı sıra dört farklı gerçek dünya mühendislik tasarım probleminin çözümünde de uygulanmıştır. Sunulan çalışma, optimizasyon algoritmalarının en önemli özelliği olan keşif ve sömürü evreleri arasındaki denge ve kararlılığı sağlamaya yönelik yeni ve farklı birtakım yaklaşımlar getirmektedir. Sunulan parçacık tabanlı güncelleme, ortalama tabanlı birey havuzu, yönlü tarama ve en iyi popülasyon seçimi teknikleri literatüre kazandırılmış yenlikler olarak öne çıkmaktadır.The Equilibrium Optimisation (EO) algorithm is a physics-based optimisation algorithm inspired by the law of mass balance, which describes the equilibrium of substances entering, being produced and leaving a control volume. Although Equilibrium Optimisation is a well-accepted and successful algorithm in the literature, it has some weaknesses and shortcomings regarding its performance. Among the main problems are low convergence capability, getting stuck in local minima and imbalance between exploration and exploitation phases. In this thesis, two new algorithms are proposed to improve the performance of the Equilibrium Optimisation (EO) algorithm and overcome its existing shortcomings. The first proposed algorithm is the Boosted Equilibrium Optimiser (BEO) algorithm. The presented algorithm provides new methods for the initial population, candidate pool generation and updating phases. In the proposed algorithm, the exploration phase is strengthened by using a uniformly distributed random initial population and a mean-based concentration pool strategy instead of the traditional random initial population. In addition, the two new approaches proposed for the update phase aim to provide a more stable balance between the exploration and exploitation phases. The second proposed algorithm presents a new strategy for the update mechanism of the Equilibrium Optimiser algorithm. In the existing Equilibrium Optimization algorithm, the search agents are updated collectively without considering their individual success states, which makes it difficult to reach an optimal solution, especially in multimodal optimisation problems. The proposed Particle Update Based Equilibrium Optimisation Algorithm (PUBEO) aims to overcome this problem by evaluating and updating the search agents individually. For the performance tests of the algorithms, a test set containing a total of 23 classical test functions, including unimodal, multimodal and fixed-size multimodal test functions, was first used. The performance tests of the BEO algorithm were carried out firstly between EO and the developed variant algorithms, and then between some other algorithms accepted in the literature. In order to evaluate the performance of the BEO algorithm, the CEC-2017 test set consisting of 29 functions was used in addition to the classical test problems. In addition to these tests, both proposed algorithms were also applied to solve four different real-world engineering design problems. The presented work introduces a few new and different approaches to ensure the balance and stability between the exploration and exploitation phases, which is the most important feature of optimisation algorithms. Particle-based updating, mean-based individual pooling, directional scanning and best population selection techniques are some of the innovations introduced in the literature

Tİ ve NB ilaveli toz metal 316 L paslanmaz çeliğe deformasyonun etkisinin incelenmesi

In this study, titanium (Ti) and niobium (Nb) elemental powders were synergistically added to 316 L stainless steel matrix in determined amounts (0.1% and 0.2% by weight) using powder metallurgy (PM) technology. The powders used in the study were cold press sample molds prepared in accordance with ASTM E8M standards and were formed into blocks by unidirectional cold pressing under 750 MPa compression pressure. After the pressing process, the raw strength samples were sintered in an atmosphere-controlled tube furnace at 1310 °C in an argon atmosphere for two hours. The produced samples were subjected to hot rolling at 40% and 80% ratios after pre-annealing at 1150 °C. Microstructure examinations of PM steels produced by sintering and hot rolling methods were carried out with optical microscope and SEM device, and elemental examinations were carried out with EDX method. The samples were also characterized using hardness test, density test and wear test. The results showed that the steel containing 316 L+0.2Ti+0.2Nb and 80% hot rolled had the highest hardness and wear resistance. In the microstructure examinations, it was observed that the grains became thinner depending on both the element addition and the rolling ratio.Bu çalışmada, 316 L paslanmaz çelik matris içerisine titanyum (Ti) ve Niyobyum (Nb) element tozları, toz metalurjisi (TM) teknolojisi kullanılarak belirlenen miktarlarda (ağırlıkça %0,1 ve %0,2) birlikte sinerjistik olarak eklenmiştir. Çalışmada kullanılan tozlar ASTM E8M standartlarına uygun olarak hazırlanan soğuk pres numune kalıpları olup 750 MPa sıkıştırma basıncı altında tek yönlü soğuk preslenerek blok haline getirilmiştir. Presleme işleminden sonra ham mukavemet numuneleri atmosfer kontrollü tüp fırında 1310 °C sıcaklıkta argon atmosferinde iki saat sinterlenmiştir. Üretilen numuneler 1150 °C ön tavlamanın ardından %40 ve %80 oranlarında sıcak haddelemeye tabi tutulmuştur. Sinterleme ve sıcak haddeleme yöntemi ile üretilen TM çeliklerin mikroyapı incelemeleri optik mikroskop ve SEM cihazı ile, elementel incelemesi ise EDX yöntemi ile yapılmıştır. Numuneler ayıca sertlik testi, yoğunluk testi ve aşınma testi kullanılarak karakterize edilmiştir. Sonuçlar 316 L + 0,2 Ti +0,2 Nb içeren ve %80 haddelenen çeliğin en yüksek sertlik ve aşınma dayanımına sahip olduğunu gösterdi. Mikroyapı incelemelerinde ise hem element ilavesine bağlı olarak hem de haddeleme oranına bağlı olarak tanelerin inceldiği gözlenmiştir.Bu tez çalışması, Karabük Üniversitesi Bilimsel Araştırma Projeleri Koordinatörlüğü tarafından KBÜBAP-24-YL-139 numaralı tez projesi kapsamında desteklenmiştir

The role of technology in the future of restaurant labor

Purpose: This research aims to explore the role of technology in the future of restaurant labor. It focused on the opinions of restaurant employees, including managers, regarding technological trends such as service robots, self-service kiosks, robot chefs and automated cooking systems and how these may affect the future of restaurant labor. Design/methodology/approach: A qualitative research approach was adopted, and interviews were conducted with restaurant employees in the USA. Findings: The findings uncovered that the benefits, impacts and shortcomings of technological trends in the restaurant industry differ depending on employees’ perspectives. Also, the findings of the shortcomings of each technological trend support the need for human labor as some aspects of technological trends cannot address the requirements of some tasks. Originality/value: This research proposed a conceptual framework explaining the role of technological trends in the future of restaurant labor. It is one of the first studies to examine the role of technology in the future of hospitality labor, specifically restaurant labor, after the pandemic

Effectuality of frequency dependent dielectric characterization of (N:DLC) film deposition between the metal-semiconductor interface

Dielectric characterization of metal-interlayer-semiconductor (MIS) structures of N-doped Diamond-Like Carbon (N:DLC) film-coated interlayer is performed to assess their dielectric properties, AC electrical conductivity (σac), and polarization mechanisms. The interlayer's structural analysis is performed using Scanning Electron Microscopy (SEM) and X-ray Photo-electron Spectroscopy (XPS). The in-phase and out-of-phase parts of the complex dielectric constant (ε∗), the complex electric modulus (M∗), the values of tangent loss (tanδ), and σac are determined utilizing admittance-voltage (Y = 1/Z = G + jωC) measurements revealing that their strong sensitivity to voltage and frequency. Remarkably, a relative permittivity (ε′) of 407 at 1 kHz, 104 times higher than traditional SiO2 insulators, is observed, suggesting a significantly enhanced electron density and energy storage capacity for ultracapacitors. The double logarithmic σac vs f plot slope changes between 0.36 and 0.20 at strong accumulation. The intersection point in σac implies a lack of free electrons at higher frequencies, suggesting an electron trapping or recombination process

Maximum power point tracking improvement based on ‎ harris hawks optimization for solar photovoltaic systems

Bu çalışmada, Maksimum Güç Noktası Takibi (MGNT), özellikle değişen güneş radyasyonu koşulları altında güneş fotovoltaik (FV) sistemlerinin performansını optimize etmek için çok önemli bir tekniktir. Perturb-and-Gözlem (P&G) ve Artan İletkenlik (Aİ) gibi geleneksel MGNT algoritmaları, basitlikleri ve uygulama kolaylıkları nedeniyle yaygın olarak kullanılmaktadır. Ancak bu algoritmalar, özellikle güneş radyasyonundaki hızlı değişimler sırasında yakınsama hızı ve kararlılık açısından genellikle sınırlamalar sergilemektedir. Bu araştırma, bu zorlukların üstesinden gelmek için Harris Hawks Optimizasyon (HHO) algoritmasını P&G ve Aİ teknikleriyle birleştiren gelişmiş bir MGNT yaklaşımı sunmaktadır. Önerilen hibrit HHO-P&G ve HHO-Aİ algoritmaları, özellikle dinamik çevre koşulları altında Maksimum Güç Noktası Takibinin yakınsama hızını ve izleme doğruluğunu iyileştirmeyi amaçlamaktadır. HHO algoritmasının uyarlanabilir ve keşfedici yeteneklerinden yararlanarak, sistem güç-gerilim eğrisinde daha etkili bir şekilde gezinebilir, maksimum güç noktasına (MGN) ulaşmak için gereken süreyi azaltabilir ve salınımlardan kaynaklanan güç kayıplarını en aza indirebilir. Simülasyon sonuçları, hibrit HHO-P&G ve HHO-Aİ algoritmalarının daha hızlı yakınsama, gelişmiş izleme verimliliği ve hızlı radyasyon değişikliklerine karşı daha fazla dayanıklılık açısından geleneksel P&G ve Aİ yöntemlerinden daha iyi performans gösterdiğini ve gerçek zamanlı güneş FV uygulamaları için son derece uygun olduğunu göstermektedir.In this study, Maximum Power Point Tracking (MPPT) is a crucial technique for optimizing the performance of solar photovoltaic (PV) systems, particularly under varying solar radiation conditions. Traditional MPPT algorithms, such as Perturb-and-Observe (P&O) and Incremental Conductance (INC), are commonly used due to their simplicity and ease of implementation. However, these algorithms often exhibit limitations in terms of convergence speed and stability, especially during rapid changes in solar radiation. This investigation presents an enhanced MPPT approach that combines the Harris Hawks Optimization (HHO) algorithm with P&G and INC techniques to overcome these challenges. The proposed hybrid HHO-P&G and HHO-INC algorithms aim to improve the convergence speed and tracking accuracy of Maximum Power Point Tracking, particularly under dynamic environmental conditions. By leveraging the adaptive and exploratory capabilities of the HHO algorithm, the system can more effectively navigate the power-voltage curve, reducing the time needed to reach the maximum power point (MPP) and minimizing power losses due to oscillations. Simulation results demonstrate that the hybrid HHO-P&G and HHO-INC algorithms outperform traditional P&G and INC methods in terms of faster convergence, enhanced tracking efficiency, and greater resilience to rapid radiation changes, making them highly suitable for real-time solar PV applications

Linking gamers’ competitive spirit and in-game impulse purchase: The need for popularity as a mediator and social competence as a moderator

This study investigated the effects of competitive attitudes on in-game impulse purchase behaviors, focusing on the mediating role of the need for popularity and the moderating effect of social competence. Data collected from 234 participants via broadcasters on Discord and Twitch platforms was analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM). The findings confirm that the need for popularity fully mediates the relationship between competitive attitudes and in-game impulse purchases. Moreover, social competence was found to moderate this relationship negatively, indicating that individuals with lower social competence are more influenced by their need for popularity when making in-game impulse purchases. These insights highlight the significant impact of social dynamics and individual psychological traits on consumer behavior in gaming environments. Furthermore, these results emphasize the ethical imperative for game developers to implement protective measures to safeguard consumers from the potential negative effects of in-game impulse purchases

An additional value for the disposed wastes: An experimental and RSM optimization study based on the enhancement of waste plastic oil/diesel fuel blend with optimum B₂O₃ nanoparticles for cleaner emissions

This study was funded by Karabuk University's Scientific Research Project KBUEBAP-22-YL-108. Bu çalışma Karabük Üniversitesi Bilimsel Araştırma Projesi KBUEBAP-22-YL-108 kapsamında desteklenmiştir.In the current study, the ability of waste cable pyrolysis oil (WCPO) and boron oxide (B2O3) nanoparticles to improve diesel engine response was evaluated. Firstly, WCPO was produced and 20 % was determined as the most suitable mixture ratio for diesel engines. Then, different amounts (20, 40, and 60 ppm) of B2O3 were added to the fuel mixture containing 20 % WCPO/80 % diesel to strengthen the negative aspects of WCPO. The addition of 20 % WCPO reduced BTHE by an average of 7.93 % and with the positive effect of the addition of 20 ppm B2O3, this reduction was increased to an average of 0.83 %. Furthermore, the addition of B2O3 nanoparticles decreased CO and HC emissions, whereas the addition of 20 % WCPO enhanced them. HC decreased by 27.18 % with 20 ppm B2O3, after increasing by an average of 5.61 % with WCPO20 compared to diesel. Likewise, for CO, there was a 67.96 % increase with WCPO20 and a 5.92 % drop with 20 ppm B2O3. However, response surface methodology (RSM) optimization was also carried out to determine the ideal concentration of B2O3 because nanoparticles are expensive. In RSM optimization, the quantity of B2O3 (QoN) and engine load were modeled as variables, and brake thermal efficiency (BTHE), brake-specific fuel consumption (BSFC), nitrogen oxide (NOx), carbon monoxide (CO), hydrocarbon (HC), and carbon dioxide (CO2) were modeled as responses. According to the model, the optimum B2O3 amount was determined as 22 ppm at 1500 W load. Under these conditions, the best results for BTHE, BSFC, NOx, CO, HC, and CO2 are 24.5755 %, 387.533 g/kWh, 523.141 ppm, 0.0413 %, 23.7139 ppm, and 5.2072 % respectively. Moreover, the composite desirability value was within acceptable limits at 0.7156. In addition, the maximum difference between the RSM and the experimental results was 4.81 %, indicating that the RSM gave successful results in this study.Funding agency Karabuk University's Scientific Research Project Grant number KBUEBAP-22-YL-10

Hydrothermal carbonization of citrus peels and their electrochemical efficacy in double-layer supercapacitors

The authors express gratitude to Karabuk University, BAP Office for financial assistance under project number KBUBAP-23-YL-039. Yazarlar, KBUBAP-23-YL-039 proje numarası kapsamında verdikleri mali destek için Karabük Üniversitesi BAP Ofisi’ne şükranlarını sunarlar.This work involved the fabrication of supercapacitors with rapid charge/discharge rates using waste biomass. Initially, hydrochars were produced using the hydrothermal carbonization of four distinct citrus peels. Subsequently, physical, acidic, and basic activation was employed to enhance surface area and induce porosity. They were analyzed using elemental analysis, FTIR spectroscopy, and SEM examination. The electrochemical performance of the electrodes was assessed using galvanostatic charge-discharge and cyclic voltammetry techniques. The maximum specific capacity recorded was 65.1 mF/cm2 at a current rate of 0.50 mA for the electrode produced through potassium hydroxide activation and calcination. Consequently, it was demonstrated that supercapacitors with comparable specific capacity values may be fabricated from these waste orange peels.Funding agency : Karabuk University BAP Office Grant number : KBUBAP-23-YL-03

The Effect of Graphene Nanoparticles on the Mechanical Properties of Woven Aramıd/Epoxy Composites

In this study, the effect of the amount of graphene added to aramid fiber/epoxy composites on the mechanical properties of these composites was investigated. In the study, graphene nanoparticles were added to the epoxy matrix at four different rates and mixed by mechanical methods, and then 5-layer aramid epoxy graphene composite plates were obtained using hand lay-up and vacuum infusion methods. Samples were cut from these composite plates according to ASTM 790 for bending test and ASTM D3039 for tensile test and three-point bending and tensile tests were performed. Microstructure examinations were carried out under a macro microscope. After the studies, it was observed that agglomeration occurred in the microstructures of the produced composites. It was determined that graphene added to the aramid epoxy composite increased the bending strength and bending modulus, the highest bending stress was observed in the samples with 1% graphene added. The flexural strength, which compared to the undoped composite, increased about 64 % in this sample. In addition, the highest tensile strength was measured in the undoped sample, and after the 0.25% graphene addition, the tensile strength decreased due to the agglomeration of graphene that occurred in the structure. Bu çalışmada aramid fiber /epoksi kompozitlere ilave edilen grafen miktarının bu kompozitlerin mekanik özelliklerine etkisi incelenmiştir. Çalışmada epoksi matris içerisine dört farklı oranda grafen nanopartiküller ilave edilerek mekanik yöntemle karıştırıldıktan sonra el yatırma ve vakum infüzyon yöntemleri kullanılarak 5 katlı aramid epoksi grafen kompozit plakalar elde edilmiştir. Elde edilen bu kompozit plakalardan eğme testi için ASTM 790 ve çekme testi için ASTM D3039 standartlara göre numuneler kesilerek üç nokta eğme ve çekme testleri yapılmıştır. Mikro yapı incelemeleri makro mikroskop altında yapılmıştır. Yapılan çalışmalar sonrasında üretilen kompozitlerin mikro yapılarında aglomerasyonun oluştuğu gözlemlenmiştir. Aramid epoksi kompozite ilave edilen grafenin eğilme dayanımı ve eğilme modülünü arttırdığı %1 grafen ilave edilen numunelerde en yüksek eğilme gerilmesi gözlenmiştir. Katkısız numunelere göre bu numunede eğilme mukavemeti yaklaşık %64 oranında artmıştır. Ayrıca çekme testleri sonrasında en yüksek çekme dayanımının katkısız numunelerde olduğu, %0.25 den daha fazla grafen ilave edilen numunelerde ise grafenin yapıda oluşturduğu aglomerasyona bağlı olarak çekme dayanımının düştüğü tespit edilmiştir

Assessing fire susceptibility of threatened plant species in temperate forest ecosystem of Azerbaijan using MaxEnt method

Natural and human-induced disturbances are major drivers of the decline and loss of vulnerable species worldwide. Among these, fires are particularly disruptive as they can devastate entire ecosystems. Assessing the likelihood and severity of such disturbances on plant communities is crucial for the management and conservation of biodiversity. This study aims to analyze fire susceptibility using the Maximum Entropy (MaxEnt) model to evaluate the potential impacts of fires on the biodiversity of a lowland forest in Azerbaijan. The research was conducted as part of the project on the evaluation of Red Book species in Azerbaijan based on IUCN categories and criteria. In this study, 21 rare plant species found in the Samur-Yalama National Park (SYNP) were assessed for fire susceptibility, as they have been significantly affected by fires in recent years. The fire susceptibility analysis included 12 driving factors, categorized into topographic, vegetation, and climatic factors, and identified 564 wildfire incidents. Model performance was evaluated using the AUC value, which was 0.855, indicating good model accuracy. Fire susceptibility was classified into three categories: low, moderate, and high. According to the results, 12,642 hectares (60.82%) of the SYNP area fall under low susceptibility, 5532 hectares (26.62%) under moderate susceptibility, and 2611 hectares (12.56%) under high susceptibility. Rare plant species in SYNP were evaluated based on their fire susceptibility. It was found that Alcea kusariensis (Iljin ex Grossh.) Iljin, Anacamptis morio subsp. picta (Loisel.) Jacquet & Scappat., Equisetum hyemale L., Orchis purpurea Huds., Pinus brutia var. eldarica (Medw.) Silba, Platanus orientalis L., Punica granatum L., and Quercus castaneifolia C.A.Mey are located in areas classified as having high susceptibility