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A survey on communication protocols and performance evaluations for Internet of Things

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Digital Communications and Networks 2022年第6期8卷 1094-1104页

作者： Cüneyt Bayılmış MAli Ebleme ÜnalÇavuşoğlu kerem küçük Abdullah Sevin Department of Computer Engineering Sakarya UniversitySerdivanSakaryaTurkey Institute of Natural Science Sakarya UniversitySakaryaTurkey Department of Software Engineering Sakarya UniversitySerdivanSakaryaTurkey Department of Software Engineering Kocaeli UniversityKocaeliTurkey

The Internet of Things (IoT) is a large-scale network of devices capable of sensing, data processing, and communicating with each other through different communication protocols. In today's technology ecosystem, IoT interacts with many application areas such as smart city, smart building, security, traffic, remote monitoring, health, energy, disaster, agriculture, industry. The IoT network in these scenarios comprises tiny devices, gateways, and cloud platforms. An IoT network is able to keep these fundamental components in transmission under many conditions with lightweight communication protocols taking into account the limited hardware features (memory, processor, energy, etc.) of tiny devices. These lightweight communication protocols affect the network traffic, reliability, bandwidth, and energy consumption of the IoT application. Therefore, determining the most proper communication protocol for application developers emerges as an important engineering problem. This paper presents a straightforward overview of the lightweight communication protocols, technological advancements in application layer for the IoT ecosystem. The survey then analyzes various recent lightweight communication protocols and reviews their strengths and limitations. In addition, the paper explains the experimental comparison of Constrained Applications Protocol (CoAP), Message Queuing Telemetry (MQTT), and WebSocket protocols, more convenient for tiny IoT devices. Finally, we discuss future research directions of communication protocols for IoT.

关键词： Internet of Things IoT application layer protocols IoT communicati on pr otocols Performance evaluation

Spatial statistical analysis of earthquakes in the Fethiye-Burdur fault zone

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Frontiers of Earth Science 2024年第3期18卷 554-564页

作者： kerem HEPDENIZ Department of Architecture and Urban Planning Bucak EG Technical Sciences and Vocational School of Higher EducationMehmet Akif Ersoy UniversityBurdur 15030Turkey

Turkey is located in the Alpine-Himalayan seismic *** Anatolian plate has witnessed very severe and destructive earthquakes both in the past and *** this study,statistical analyses of earthquakes that occurred between 1914 and 2019 along the Fethiye-Burdur fault zone,which is an active line,were conducted using geographic information *** of standard distance,standard deviational eclipse,mean center,and median center were conducted to determine the geographic distributions of epicenters with a magnitude value of 3.5 and *** and Average Nearest Neighbor analyses were used to reveal the spatial *** Local Moran I and Getis Ord Gi*method were used to determining where the earthquake epicenters are clustered *** Density analyses were conducted to measure earthquake epicenters’*** analysis,Average Nearest Neighbor,Global Moran’s I,and Getis-Ord General G indices demonstrated that earthquakes are clustered in certain regions and are related to each other *** Moran’s I regional analyses revealed that high values were clustered in the West of Burdur city center and the district of Yeşilova,and similar results were obtained in the Getis Ord Gi*method.

关键词： earthquake Geographic Information Systems spatial analysis Fethiye-Burdur fault zone Turkey

Infiltration of A6063 aluminium alloy into SiC-B_4C hybrid preforms using vacuum assisted block mould investment casting technique

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Transactions of Nonferrous Metals Society of China 2012年第7期22卷 1563-1567页

作者： Alptekin kISASOZ kerem Altug GULER ahmet kARAASLAN Department of Metallurgy and Materials Engineering Yildiz Technical UniversityDavutpasa CampusTR 34210EsenlerIstanbulTurkey

Production of A6063/SiC-B4C hybrid composite using vacuum assisted block mould investment casting was investigated. Firstly,SiC-B4C hybrid preforms were fabricated in cylindrical *** preferred mean particle size of the SiC and B4C powders were 60μm and 55μm *** early experiments,single powder ratio of 85%SiC and 15%B4C was selected to produce the tough ***,the preforms were placed into the cylindrical shape gypsum bonded block investment moulds and A6063 alloy was infiltrated into the preforms using vacuum assisted（-10 5 Pa）casting *** fraction of preforms was determined using Archimedes’*** fabricated cast specimens were characterized using hardness tests,image analysis and SEM observations and EDX *** result indicates that,by the vacuum assisted block mould investment casting technique,the infiltration of the preforms by molten metal was successfully realized.

关键词： AlMMC SiC B4C investment casting hybrid preform

Cooling slope casting of AA7075 alloy combined with reheating and thixoforging

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Transactions of Nonferrous Metals Society of China 2019年第11期29卷 2237-2244页

作者： kerem Altug GULER Alptekin kISASOZ Gokhan OZER ahmet kARAASLAN Department of Metallurgical and Material Engineering Yildiz Technical UniversityTR34210IstanbulTurkey Aluminium Test Training and Research Center(ALUTEAM)Fatih Sultan Mehmet Vakif UniversityTR34445Halic CampusIstanbulTurkey

Cooling slope casting has been applied to aluminium casting alloys for producing ingots with non-dendritic ***-solid forming of the AA7075 was studied via cooling slope casting,reheating and thixoforging processes in order to determine the effect of semi-solid casting on the microstructure of the ***7075 ingots with non-dendritic microstructure were produced with cooling slope *** were characterized by light microscopy,image analysis,scanning electron microscopy and EDS *** resulting structures are promising in terms of grain size and *** was realized that grain coarsening may occur very suddenly in the reheating *** slope castings were obtained with 30°and 60°inclination angles,and in comparison,60°castings showed better ***,by using short reheating periods,semi-solid forging causes trace formation in the solid grains.

关键词： semi-solid alloy cooling slope casting thixoforging AA7075 alloy

Influence of T6 heat treatment on A356 and A380 aluminium alloys manufactured by thixoforging combined with low superheat casting

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Transactions of Nonferrous Metals Society of China 2018年第3期28卷 385-392页

作者： Ridvan GECU Serhat ACAR Alptekin kISASOZ kerem ALTUG GULER ahmet kARAASLAN Department of Metallurgical and Materials Engineering Yildiz Technical UniversityDavutpasa Campus

The effects of T6 heat treatment on thixoforged A356 and A380 aluminium alloys were *** superheat casting(LSC)technique was carried out to prepare proper specimens for thixoforging *** samples were poured at 20°C above their liquidus temperatures which provided the formation of equiaxed grains instead of dendritic *** billets were reheated for varied time from 20 to 80 min and thixoforged with 50%deformation *** thixoforging process,the samples were T6 heat treated for both A356 and A380 *** microstructural evaluation and hardness alteration of thixoforged,solution treated and aged specimens were examined comparatively by using optical microscopy,scanning electron microscopy with energy-dispersive X-ray spectroscopy and Brinell hardness equipment.T6 heat treatment provided relatively uniform microstructure with newly formed precipitates that are Mg2Si and Al2Cu for A356 and A380 billets,***,hardness after artificial aging was increased considerably and reached HB 93 for A356 and HB 120 for A380 alloys.

关键词： T6 heat treatment thixoforging low superheat casting aluminium alloy

Soft metamaterial with programmable ferromagnetism

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Microsystems & Nanoengineering 2022年第6期8卷 217-223页

作者： kerem kaya Emre Iseri Wouter van der Wijngaart Division of Micro and Nanosystems KTH Royal Institute of TechnologyStockholm 10044Sweden

Magnetopolymers are of interest in smart material applications;however,changing their magnetic properties post synthesis is *** this study,we introduce easily programmable polymer magnetic composites comprising 2D lattices of droplets of solid-liquid phase change material,with each droplet containing a single magnetic dipole *** composites are ferromagnetic with a Curie temperature defined by the rotational freedom of the particles above the droplet melting *** demonstrate magnetopolymers combining high remanence characteristics with Curie temperatures below the composite degradation *** easily reprogram the material between four states:(1)a superparamagnetic state above the melting point which,in the absence of an external magnetic field,spontaneously collapses to;(2)an artificial spin ice state,which after cooling forms either;(3)a spin glass state with low bulk remanence,or;(4)a ferromagnetic state with high bulk remanence when cooled in the presence of an external magnetic *** observe the spontaneous emergence of 2D magnetic vortices in the spin ice and elucidate the correlation of these vortex structures with the external bulk *** also demonstrate the easy programming of magnetically latching structures.

关键词： composites composite ferromagnetic

Advanced Optimized Anomaly Detection System for IoT Cyberattacks Using Artificial Intelligence

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Computers, Materials & Continua 2024年第2期78卷 1525-1545页

作者： Ali Hamid Farea Omar H.Alhazmi kerem kucuk Department of Computer Science Taibah UniversityMedina42315Saudi Arabia Department of Software Engineering Kocaeli UniversityKocaeli41001Turkey

While emerging technologies such as the Internet of Things(IoT)have many benefits,they also pose considerable security challenges that require innovative solutions,including those based on artificial intelligence(AI),given that these techniques are increasingly being used by malicious actors to compromise IoT *** an ample body of research focusing on conventional AI methods exists,there is a paucity of studies related to advanced statistical and optimization approaches aimed at enhancing security *** contribute to this nascent research stream,a novel AI-driven security system denoted as“AI2AI”is presented in this ***2AI employs AI techniques to enhance the performance and optimize security mechanisms within the IoT *** also introduce the Genetic Algorithm Anomaly Detection and Prevention Deep Neural Networks(GAADPSDNN)sys-tem that can be implemented to effectively identify,detect,and prevent cyberattacks targeting IoT ***,this system demonstrates adaptability to both federated and centralized learning environments,accommodating a wide array of IoT *** evaluation of the GAADPSDNN system using the recently complied WUSTL-IIoT and Edge-IIoT datasets underscores its *** an impressive overall accuracy of 98.18%on the Edge-IIoT dataset,the GAADPSDNN outperforms the standard deep neural network(DNN)classifier with 94.11%***,with the proposed enhancements,the accuracy of the unoptimized random forest classifier(80.89%)is improved to 93.51%,while the overall accuracy(98.18%)surpasses the results(93.91%,94.67%,94.94%,and 94.96%)achieved when alternative systems based on diverse optimization techniques and the same dataset are *** proposed optimization techniques increase the effectiveness of the anomaly detection system by efficiently achieving high accuracy and reducing the computational load on IoT devices through the adaptive selection of active features.

关键词： Internet of Things security anomaly detection and prevention system artificial intelligence optimization techniques

Investigation of carbon contamination in lost foam castings of low carbon steel

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China Foundry 2018年第5期15卷 384-389页

作者： Oznur kilic Serhat Acar Alptekin kisasoz kerem Altug Guler Department of Metallurgical and Materials Engineering Yildiz Technical UniversitylstanbulTurkey

Lost foam casting(LFC) process is a special casting method in which polymeric foam patterns with refractory coatings are utilized as a mould component. In this work, four types of foam: expandable polyethylene(EPE), expandable polypropylene(EPP) and expandable polystyrene(EPS) foams with two different densities were employed as pattern materials. LFC and conventional green sand mould casting methods were used to cast a low carbon steel, A216 Grade WCB. Both casting processes were carried out at 1,580 °C. Chemical analysis results showed that the carbon contamination level was high and was influenced by pattern type. Metallographic investigations revealed a significant increase in the percentage of pearlite phase in all LFC samples. Densities of manufactured samples were calculated in order to evaluate porosity of the products. It was determined that the densities of the LFC samples were lower than the green sand mould cast reference sample(RS). Vickers hardness tests were also carried out and increments in hardness values with increased carbon content was observed.

关键词： lost foam casting (LFC) EPS pattern EPE pattern EPP pattern carbon contamination A216 Grade WCB

A Late Cretaceous ensimatic arc developed during closure of the northern branch of Neo-Tethys(central-northern Turkey)

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Geoscience Frontiers 2019年第3期10卷 1015-1028页

作者： Metin Beyazpirin? Ali Ekber Ak?ay Ali Yilmaz Meftun kerem S?nmez Geological Research Department General Directorate of Mineral Research and Exploration (MTA) Department of Environmental Engineering Engineering Faculty Cumhuriyet University

Studies on differentiation of ensimatic arc units from melange units in the Northern Anatolian Ophiolitic Belt(NAOB) are very rare. The study area represents the southern edge of the central part of the *** aim of the study is to distinguish the main units of NAOB and to define the geotectonic setting of the Darmik Ensimatic Arc Association(DEAA). To study the ensimatic arc units as an independent tectonic unit is important and facilitates understanding of the geological evolution of the NAOB. During field studies, the contact relationships within the Darmik Ensimatic Arc Association(DEAA) units and also with other tectonic units were reviewed. Then, paleontological, geochronological, petrological and also geochemical properties of the DEAA have been defined. In the present study, ensimatic arc units have been distinguished from ophiolitic association for the first time, in the region. As a result of the study, the DEAA is divided into two levels and lower level named as the kartal unit and upper level named as the izibüyük unit. In the kartal unit, basaltic and andesitic lavas with their equivalent pyroclastic rock units are dominant. Radiolarite and mudstones interbedded within the kartal unit of DEAA have Turonian and Santonian age. In addition, the age of basalt samples of DEAA are 98.7 ± 2.4 Ma, defined using the^(40)Ar/39 Ar method. The izibüyük unit of DEAA comprises conglomerate, sandstone, claystone, mudstone,clayey limestone, micritic limestone with volcanic interbeds and also calciturbidites. Santonian-Maastrichtian ages were obtained from this unit of the DEAA. In conclusion, the age of DEAA is widely accepted as Late Cretaceous. After the evaluation of the analysis, the volcanics of the DEAA originated from calcalkaline-basalts, which reflect ensimatic arc magmatism.

关键词： North Anatolian Ophiolitic Belt Double subduction zones Darmik ensimatic arc Turkey