In Advanced Metering Infrastructure (AMI) networks, smart meters should send\nfine-grained power consumption readings to electric utilities to perform\nreal-time monitoring and energy management. However, these readings can leak\nsensitive information about consumers' activities. Various privacy-preserving\nschemes for collecting fine-grained readings have been proposed for AMI\nnetworks. These schemes aggregate individual readings and send an aggregated\nreading to the utility, but they extensively use asymmetric-key cryptography\nwhich involves large computation/communication overhead. Furthermore, they do\nnot address End-to-End (E2E) data integrity, authenticity, and computing\nelectricity bills based on dynamic prices. In this paper, we propose EPIC, an\nefficient and privacy-preserving data collection scheme with E2E data integrity\nverification for AMI networks. Using efficient cryptographic operations, each\nmeter should send a masked reading to the utility such that all the masks are\ncanceled after aggregating all meters' masked readings, and thus the utility\ncan only obtain an aggregated reading to preserve consumers' privacy. The\nutility can verify the aggregated reading integrity without accessing the\nindividual readings to preserve privacy. It can also identify the attackers and\ncompute electricity bills efficiently by using the fine-grained readings\nwithout violating privacy. Furthermore, EPIC can resist collusion attacks in\nwhich the utility colludes with a relay node to extract the meters' readings. A\nformal proof, probabilistic analysis are used to evaluate the security of EPIC,\nand ns-3 is used to implement EPIC and evaluate the network performance. In\naddition, we compare EPIC to existing data collection schemes in terms of\noverhead and security/privacy features.\n
Abstract In the present research, brewed tea waste (BTW) was utilized as a green, low-priced, and abundant adsorbent for separation/preconcentration of Cd(II) ions through solid-phase extraction method from water and foods for the first time. BTW was applied as a natural adsorbent, without using any chelating agent to bind Cd(II) ions or any chemical reagent for its modification. A three-layer artificial neural network model using backpropagation algorithm was utilized to explicate a prediction model for the extraction performance of Cd(II) ions by selecting the input parameters as solution pH, quantity of BTW, sample volume, eluent concentration and volume, and equilibrium time for desorption. The preconcentration factor, relative standard deviation, and detection limit were attained as 100, 3.03%, and 0.56 µg L −1 , respectively. It was decided that the Langmuir isotherm model is acceptable to characterize the retention of Cd(II) ions on BTW. This result pointed out that the active binding sites on the BTW surface are homogeneously distributed. Adsorption capacity of BTW was achieved as 41.5 mg g −1 which is higher than several expensive and difficult-to-prepare adsorbents. Adsorption kinetics was elucidated by pseudo-second order kinetic model. After confirmed the accuracy of the method with spike/recovery studies, it was employed for Cd(II) determination in water (stream and sea water) and food (eggplant, lettuce, parsley, apple, and apricot) samples with high accuracy. The inferences of the study proved that the BTW offers a magnificent application prospect in the extraction of Cd(II) ions.
Sıraya Dayalı Seyyar Satıcı Problemi için Çözüm Yaklaşımları\nSıraya Dayalı Seyyar Satıcı Problemi (SDSSP), Seyyar Satıcı Problemi’nin (SSP) genellemesi olarak tanımlanmış bir birleşimsel eniyileme problemidir. Bu problem, Baskılı Devre Kartı (BDK) üretiminde çokça kullanılan iki önemli dizgi makine tipinin eniyilenmesi sırasında ortaya çıkmıştır. SDSSP’yi SSP’den ayıran fark şu şekilde ifade edilebilir: SDSSP’de bir noktadan diğerine gitmenin maliyeti sadece noktalar arasındaki uzaklığa değil, gezinme sırasında sonradan gelecek k tane noktanın hangileri olduğuna da bağlıdır.\nBu çalışmada, Benzetimli Tavlama (BT), Yapay Arı Kolonisi (YAK) ve Göç eden Kuşlar (GK) isimli üç üstsezgiselden yararlandık. Bu üstsezgiseller 10 komşu fonksiyonu ile test edildi. Yaptığımız sayısal çalışmada, beş ayrı kümeden oluşan testler yaptık. İlk olarak, her bir üstsezgisel için en iyi parametre kombinasyonunu elde ettik. Daha sonra her bir üstsezgiselin en iyi başarım gösterdiği komşu fonksiyonu belirlemek için testler yaptık. Bu testlerden sonra üstsezgisellerin başarımlarını karşılaştırmak için testler yaptık. BT, GK ve YAK’tan daha iyi başarım gösterdi. Bu testleri, problem özgün önemli bir parametrenin problemin karmaşıklığını hem çözüm kalitesi hem de çalışma zamanı açısından nasıl etkilediğini ortaya çıkarmak için yaptığımız testler takip etti ve bu parametrenin değerinin artmasıyla üstsezgisellerin başarımının düştüğünü gözlemledik. Burdan yola çıkarak SDSSP’nin SSP’den çok daha zor bir problem olduğu sonucuna vardık. Son olarak, problemin matematiksel modelini, GAMS’i kullanarak programladık ve bazı küçük ölçekli problem örnekleri için en iyi üst sınır çözümlerini elde ettik. Üstsezgisellerin aynı örnekler için elde ettiği çözümlerle karşılaştırdık ve üstsezgisellerin performansının problemin büyüklüğü arttıkça en iyi üst sınır çözümleriyle kıyaslanabilir olduğunu gözlemledik. Yaptığımız testler sonucunda, en iyi üst sınır çözümlerini elde etmek için gereken zamanın, problemin büyüklüğüyle üssel olarak arttığını gözlemledik. Bunun bir sonucu olarak, SDSSP ve benzeri problemlerin orta ve büyük ölçekli örneklerinin çözümlerini elde etmede, bu üstsezgiselleri kullanmanın iyi bir tercih olduğu sonucuna vardık.\nABSTRACT\nSolution Approaches for Sequence Dependent Traveling Salesman Problem\nThe Sequence Dependent Traveling Salesman Problem (SDTSP) is a combinatorial optimization problem defined as a generalization of the TSP. It emerged during optimization of two kind of commonly used placement machines for production of printed circuit boards. The difference between SDTSP and TSP is that the cost incurred by transition from one point to another is dependent not only the distance between these points but also subsequent k points.\nIn this study, we applied Simulated Annealing (SA), Artificial Bee Colony (ABC) and Migrating Birds Optimization (MBO) to solve real-world and random SDTSP instances. The metaheuristics were tested with 10 neighbour functions. In our computational study, we conducted five sets of computational experiments. Firstly, we obtained best parameter value combination for each metaheuristic. Secondly, we conducted experiments so as to determine best performing neighbour function for each metaheuristic. Thirdly, metaheuristic comparison tests were conducted. As a result, SA outperformed MBO and ABC. These tests were followed by the tests conducted to reveal how a parameter peculiar to the problem affects the complexity of the problem both in terms of run time and solution quality. As this parameter value increases, performances shown by all metaheuristics decrease. Therefore, we concluded that SDTSP is much more challenging than TSP. Finally, we programmed the mathematical model of the problem by means of GAMS and we obtained the best upper-bound solutions of some small-scale problem instances. These solutions were compared with those obtained by the metaheuristics and we observed that solution quality performance of the metaheuristics are comparable to the best upper-bound solutions returned from GAMS. In addition, we observed that the time required for obtaining the best upper-bound solution of an SDTSP instance increases exponentially with the problem size. Consequently, we deduced that using these metaheuristics to obtain solutions for medium- and large-scale instances of SDTSP and similar problems is a good choice.
Advanced Metering Infrastructure (AMI) is an indispensable part of a Smart Grid (SG) initiative. AMI applications collect data measured by smart meters in the SG. This process may leak information about consumers. In this paper, we build an IEEE 802.11s-based SG AMI network testbed consisting of Beaglebone Black boards and investigate the performance of privacy-preserving protocols in real-life and compare it with the ns-3 simulations. We develop an application that collects data periodically. This mechanism runs in two modes: Hop-by-hop and end-to-end aggregation. The application is tested on TCP and UDP. We use Paillier cryptosystem for privacy, and ECDSA for authentication. The application is also simulated in ns-3. The testbed results are compared with the ns-3 results in terms of packet delivery ratio, throughput and data collection completion time. Comparison showed that the tested privacy-preserving protocol behavior may not accurately reflect that of ns-3, especially with data completion time metric.
Abstract The gamma-ray attenuation behavior of europium (Eu)-doped Bi-2223 ceramic superconductors has been investigated in detail in this work in the photon energy range of 59.54 to 1332 keV. The WinXcom database was used to rigorously estimate the mass attenuation coefficients ( μ / ρ ), which are the main quantifiers of the probability of photon–matter interaction. Stochastic modeling based on the EGS4 Monte Carlo transport technique was then used to confirm the results. Key shielding metrics such as the mean free path (MFP), radiation protection efficiency (RPE), half-value layer (HVL), and gamma-ray kerma coefficients (k γ ) are derived from these coefficients and offer information about the material’s inherent ability to dissipate or attenuate incident photon flux. Additionally, the effective atomic number (Zeff) was established to elucidate the role of compositional heterogeneity and atomic cross-section weighting in regulating photon absorption and scattering probabilities. Concurrently, the macroscopic fast neutron removal cross-sections (ΣR) were computed to measure the dual shielding capacity of the ceramics being studied against electromagnetic radiation and neutrons. The findings showed that although Eu doping led to a minor increase in the effective atomic number and μ / ρ values at lower photon energy, it also resulted in greater HVL and MFP values, particularly at higher energies. The total shielding performance decreases due to the decrease in bulk density, even though the addition of Eu results in better mass attenuation coefficients. The μ / ρ values of Eu-doped Bi-2223 ceramics exhibit high agreement and increase from 2.753 to 3.212 cm 2 g −1 at 59.54 keV with increasing Eu content. These values were produced using EGS4 simulations and verified using WinXCOM in the 59.54–1332 keV energy range. This suggests that europium’s higher atomic number enhances photon absorption at lower energies. The study also demonstrates that the Eu-0 sample has the strongest neutron shielding capabilities and the highest radiation protection efficiency (RPE).
In this study, the Y358 phase, the newest high-temperature superconductor member of the yttrium barium copper oxide family, was produced using the solid-state reaction technique. The Y358 superconductor exhibited the Meissner effect at low temperature (77 K). The X-ray diffraction spectra indicated that the crystal structure was almost identical to that of Y123, but with some impurity peaks. An X-ray peak broadening analysis was applied to determine the lattice strain, and the medial crystallite size was calculated perpendicular to the surface of the superconductor specimens. As a result of the analyses, it was determined that the crystallite size of the Y358 superconductor was about 1.125 times larger than that of the Y123 superconductor.
Gönüllülük ve Afetlerde Gönüllülük Ömer DEMİRBİLEK Türkiye’de Afetlerde Gönüllük ve Tarihçesi Enes ARSLAN Uluslararası Alanda Afetlerde Gönüllülük ve Tarihçesi Kemal BAŞ BÖLÜM 4 Afetlerde Gönüllülük Türleri Ömer DEMİRBİLEK Afetlerde Gönüllülüğün Gerekliliği ve Önemi Salih DOĞRU Afetlerde Gönüllülük Mevzuatı Mehmet Metehan ÇETİNTAŞ Afet Gönüllülüğüne Katılım ve Motivasyon Şeyhmus AKSOY Ulusal Düzeyde Afet Gönüllülüğü: Kurumlar ve Uygulamalar Emrah GÖKKAYA Uluslararası Düzeyde Afet Gönüllülüğü: Kurumlar ve Uygulamalar Emrah GÖKKAYA Afetlerde Arama Kurtarma Gönüllülüğü: Saha Deneyimleri Musab Süleyman KÖÇER İbrahim Mete KAPLAN Afetlerde Gönüllü Yönetimi Jale YAZGAN Afad ve Sivil Toplum Kuruluşlarının Gönüllülük Uygulamalarının Değerlendirilmesi ve Literatür Kapsamında Model Önerisi Salih DOĞRU Türkiye’deki Son 15 Yıllık Afet Gönüllülüğü Araştırmaları: Sistematik Bir Literatür İncelemesi Musab Süleyman KÖÇER
Bu çalışmada, YBCO (358) süperiletkeninin manyetik-moment sıcaklık ölçümleri ve teorik analizleri araştırıldı. Manyetik Moment-Sıcaklık (M-T) eğrilerinin teorik analizi sinterleme sırasında verilen oksijen oranına bağlılığı olarak yapıldı. Elde edilen deneysel sonuçlarda, oksijen oranının değişiminin Moment-Sıcaklık eğrileri deseninde değişikliğe sebep olduğu görüldü. Deneysel sonuçlar, kritik hal modeli çerçevesinde nitel olarak tartışıldı. Oksijen oranının miktarının artmasıyla (%0, 50, 100), kritik akım yoğunluğunun (J c ) büyüklüğünün sırasıyla 50, 100 ve 0 olarak değiştiği bulundu. Her numune için teorik ve deneysel en iyi uyum eğrilerinden kritik akım yoğunluğunun alan ve sıcaklık bağlılığı belirlendi. M-T verilerine göre en iyi uyum eğrileri elde edildi ve kullanılan parametrik değerler her bir numune için karşılaştırıldı. Sonucun literatürle uyumlu olduğu görüldü.
Ceramic glass is a multipurpose solid-state material that merges the high thermal stability, mechanical strength, and chemical durability of ceramics with the transparency, light transmission, and aesthetic benefits of glass. Because of these qualities, ceramic glass can be used in both industrial and scientific settings, especially when radiation protection, high-temperature endurance, heat resistance to thermal fluctuations, and optical clarity are required. Radiation shielding properties of five distinct ceramic glass samples with the chemical formula B2O3-ZnO-K2CO3-PbO (abbreviated as BZKP) were comprehensively assessed in this study. The radiation protection parameters of B2O3-ZnO-K2CO3-PbO glass-ceramic systems, including gamma-ray kerma coefficients (kγ), half-value layer (HVL), radiation shielding efficiency (RPE), mean free path (MFP), fast neutron macroscopic cross section ΣR (cm−1), and effective atomic number (Zeff), were theoretically examined using Monte Carlo EGS4 and WinXCOM software. The radiation shielding characteristics at 20 discrete photon energies, ranging from 0.05 MeV to 2 MeV, were theoretically calculated using the EGS4 simulation code and subsequently compared with data obtained from the XCOM program. The results of this study provide solid and valuable information regarding the improved design of high-performance ceramic glasses for radiation shielding applications. To create effective shielding solutions, a comprehensive understanding of the interactions between various materials and ionizing radiation, such as neutrons and gamma rays, is essential. By combining these discoveries, scientists can create new shielding materials that make the most of materials in these critical areas while improving radiation protection.
-modified spent tea waste can be regarded as an effective, economical, and sustainable adsorbent for trace heavy metal analysis in environmental water samples, owing to its rapid extraction kinetics, high adsorption capacity, and low detection limits.
The present paper is based on experimental studies and numerical simulations on the surface fatigue failure of the PTFE-bronze layered journal bearings under real-time loading. 'Permaglide Plain Bearings P10' type journal bearings were experimentally tested under different real time dynamic loadings by using real time journal bearing test system in our laboratory. The journal bearing consists of a PTFE-bronze layer approximately 0.32 mm thick on the steel support layer with 2.18 mm thick. Two different approaches have been considered with in experiments: (i) under real- time constant loading with varying bearing widths, (ii) under different real-time loadings at constant bearing widths. Fatigue regions, micro-crack dispersion and stress distributions occurred at the journal bearing were experimentally and theoretically investigated. The relation between fatigue region and pressure distributions were investigated by determining the circumferential pressure distribution under real-time dynamic loadings for the position of every 10° crank angles. In the theoretical part; stress and deformation distributions at the surface of the journal bearing analysed by using finite element methods to determine the relationship between stress and fatigue behaviour. As a result of this study, the maximum oil pressure and fatigue cracks were observed in the most heavily loaded regions of the bearing surface. Experimental results show that PTFE-Bronze layered journal bearings fatigue behaviour is better than the bearings include white metal alloy.
Güvenlik, günümüz iletişim teknolojilerinin olmazsa olmazlarındandır. İletişim halindeki taraflar arasında akan ağ trafiğinin gizliliğinden ve bütünlüğünden emin olabilmek son derece önemlidir. Bunları sağlamak için geliştirilmiş algoritmalar ve protokoller güvenliğin sağlanmasının yanı sıra sanal özel ağlar gibi ağ erişilebilirliğinin kontrol edilebildiği özel ağların oluşturulmasında da kullanılabilir. Anahtar değişiminden şifrelemeye/deşifrelemeye, ordan dijital imzalamaya kadar birçok uygulama alanına sahip bu algoritmalar ve protokollerin öğretimi için her ne kadar fiziksel ağ ortamı oluşturup kullanmak öğretimin kalitesini artıracak olsa da böyle bir ortamın kurulması ve devamlılığının sağlanabilmesi her açıdan maliyetlidir. Bu yüzden bu tür eğitimler sırasında genellikle ağ simülatörleri kullanılır. Geliştirilen kriptografik algoritmalar ve protokoller simülatör ortamına entegre edilerek nasıl çalıştıkları uygulamalı olarak gösterilir ve ağ protokollerinin çalışma performansına etkisi bu çalışmalar sırasında gözlemlenebilir. Bu çalışmada biz ücretsiz, açık kaynak ve kaliteli destek ekibine sahip olması nedeniyle akademik çalışmalarda sıklıkla kullanılan ns-3 ağ simülatörünü ve uluslararası standartların belirlemiş olduğu kriptografik algoritma ve protokolleri içeren OpenSSL kütüphanesini kullandık. Çalışmamızın amacı OpenSSL kütüphanesini ns-3 ağ simülatörüne entegre etmektir. Özellikle ifade etmek gerekirse, biz bu çalışmada OpenSSL kütüphanesinin ve ns-3 ağ simülatörünün kurulumunun nasıl yapılması gerektiğini ve OpenSSL kütüphanesini ns-3 ağ simülatörüne entegre edebilmek için ns-3 simülatörünün yapılandırma dosyalarında ne tür düzenlemeler yapılması gerektiğini gösterdik. Son olarak, 256 bitlik anahtar kullanan ve Galois/Counter modunda çalışan AES algoritmasının ns-3 ağ simülatöründe var olan bir örnek simülasyon programına nasıl eklenmesi gerektiğini açıkladık. Çalışmamızın ağ/bilgisayar/IoT vb. güvenliği dersleri veren akademisyenler için uygulamalı gösterim konusunda faydalı olacağı kanaatindeyiz.
