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802.15.13 standardındaki optik ağların analizi ve optimizasyonu
No full textIn recent years, commercialization of visible light communication networks have started. As a result, there are multiple groups working for their standardization. In this work, we focus on one of them, which is IEEE 802.15 Task Group 13 and their 802.15.13 Optical Wireless Personal Area Networks (OWPAN) standard draft. The network generated according to the draft is analysed for network load and an algorithm to improve network throughput is proposed. In 802.15.13 draft, the MAC protocol uses contention free and contention access periods. This paper investigates how those period lengths should be determined. Our suggested algorithm improves the performance of the network at least 5% in the case of variable network traffic up to 15 active~users.Son yıllarda, görünür ışık iletişim ağlarının ticarileştirilmesi başlamıştır. Sonuç olarak, standardizasyonu için çalışan birden fazla grup var. Bu çalışmada, bunlardan biri olan IEEE 802.15 Görev Grubu 13 ve 802.15.13 Optik Kablosuz Kişisel Alan Ağları (OWPAN) standart taslağına odaklanıyoruz. Taslağa göre oluşturulan ağ, ağ yükü açısından analiz edilerek ağ verimini iyileştirmek için bir algoritma önermekteyiz. 802.15.13 taslağında, MAC protokolü çekişmesiz ve çekişmeli erişim dönemleri kullanır. Bu çalışma, bu dönem uzunluklarının nasıl belirlenmesi gerektiğini araştırmaktadır. Önerdiğimiz algoritma, değişken ağ trafiğinin 15 aktif kullanıcıya kadar olması durumunda ağ performansını en az 5\ arttırmaktadır
Evaluating the English-Turkish parallel treebank for machine translation
No full textThis study extends our initial efforts in building an English-Turkish parallel treebank corpus for statistical machine translation tasks. We manually generated parallel trees for about 17K sentences selected from the Penn Treebank corpus. English sentences vary in length: 15 to 50 tokens including punctuation. We constrained the translation of trees by (i) reordering of leaf nodes based on suffixation rules in Turkish, and (ii) gloss replacement. We aim to mimic human annotator’s behavior in real translation task. In order to fill the morphological and syntactic gap between languages, we do morphological annotation and disambiguation. We also apply our heuristics by creating Nokia English-Turkish Treebank (NTB) to address technical document translation tasks. NTB also includes 8.3K sentences in varying lengths. We validate the corpus both extrinsically and intrinsically, and report our evaluation results regarding perplexity analysis and translation task results. Results prove that our heuristics yield promising results in terms of perplexity and are suitable for translation tasks in terms of BLEU scores.TÜBİTAKPublisher versio
A new application of the traveling salesman problem: The Turkish cashier problem
No full textWe define the problem of finding a route for the cashier that minimizes the cost of transportation as the Turkish Cashier Problem (TCP). It is a special case of the well-known traveling salesman problem. To solve the TCP, we developed a heuristic algorithm, constructed a tight lower bound, and show that the heuristic algorithm performs very successfully for practical instances of the problem
Kakao çekirdeği kabuğunun değerlendirilmesi
No full textConsidering our world's limited resources, the linear economy model that operates as take- make- dispose is not sustainable anymore. There is a need to find new ways of doing business and managing resources. The food industry also started to focus on this problem since it has been reported that we waste one-third of our food. Utilization of this food waste is a significant problem both economically and environmentally. It is important to stop seeing it as waste and consider it a resource. Even though they lack technical knowledge, designers started to get into the material development process with the help of open sources and the democratization of production techniques. While developing materials, designers pay attention to both technical and experiential characteristics of products to create meaningful experiences for users. One of the sources they use for material development is food waste and byproducts. Considering these, the study aims to contribute to the utilization of cocoa bean shells, one of the main byproducts of the cocoa bean production industry, through material development. It seeks to answer how users experience the materials developed using cocoa bean shells. The study first developed two material recipes through Material Tinkering, emphasizing active learning and experimenting while doing and practicing. Then, the two developed materials' technical and experiential characterization were evaluated using Materials-to-Experiences at four levels (Ma2E4) toolkit. According to the results of these evaluations, suggestions were made for further studies.Dünyamızın sınırlı kaynakları düşünüldüğünde, al-yap-at şeklinde işleyen lineer ekonomi modeli artık sürdürülebilir değildir. İş yapmanın ve kaynakları yönetmenin yeni yollarını bulmaya ihtiyacımız var. Gıdamızın üçte birini boşa harcadığımız bilinirken gıda sektörü de bu soruna odaklanmaya başladı. Gıda atıklarının değerlendirilmesi hem ekonomik hem de çevresel açıdan önemli bir sorundur. Onları atık olarak görmeyi bırakıp bir kaynak olarak görmek önemlidir. Tasarımcılar teknik bilgiye sahip olmasalar da açık kaynaklar ve üretim tekniklerinin demokratikleşmesi ile malzeme geliştirme sürecine dahil olmaya başladılar. Tasarımcılar, malzemeleri geliştirirken, kullanıcılar için anlamlı deneyimler yaratmak için ürünlerin hem teknik hem de deneyimsel özelliklerine dikkat ederler. Malzeme geliştirmede kullandıkları kaynaklardan biri de gıda atıkları ve yan ürünleridir. Tüm bunlar göz önünde bulundurularak bu çalışmada, kakao üretim endüstrisinin ana yan ürünlerinden biri olan kakao çekirdeği kabuğunun malzeme geliştirme yoluyla değerlendirilmesine katkıda bulunmak amaçlanmıştır. Kullanıcıların kakao çekirdeği kabukları kullanılarak geliştirilen malzemeleri nasıl deneyimledikleri yanıtlanmaya çalışılmıştır. Çalışma, ilk olarak aktif öğrenmeyi, yaparken ve uygularken denemeyi vurgulayan Material Tinkering metodu aracılığıyla iki malzeme tarifi geliştirmiştir. Geliştirilen iki malzemenin teknik ve deneyimsel karakterizasyonu, Dört düzeyde Malzemeden Deneyime (Ma2E4) araştırma seti kullanılarak değerlendirilmiştir. Bu değerlendirmelerin sonuçlarına göre ileri çalışmalar için önerilerde bulunulmuştur
Path selection for relay-assisted underwater visible light communication systems
No full textIn this paper, we consider underwater visible light communication (UVLC) system with M parallel relaying paths where each path has N decode-and-forward (DF) relays. One path (not necessarily the best one) out of M paths is selected for transmission. Such a multi-hop system is especially useful since some relay nodes might break down or malfunction and hence single path might not be sufficient. Furthermore, selection of the best path is not always possible due to several reasons such as the effect of noise on the estimation of the best path and feedback error. Under the assumption of lognormal (LN) turbulence channels, we derive a closed-form expression for the outage probability of UVLC system where the mth best path is selected for transmission. We then use our derived closed-form outage probability for investigating the so-called incremental diversity order (IDO)
Non-orthogonal multiple access-based underwater VLC systems in the presence of turbulence
No full textThe promising potential of underwater applications in visible light communication (VLC) systems has recently gained considerable research attention, as an efficient technology for enabling high data rate, massive connectivity, and ultra-low latency. Different from indoor VLC, underwater wireless communications experience harsh environmental challenges, yielding a degraded performance. Non-orthogonal multiple access (NOMA) was introduced to enhance spectral efficiency and connectivity of underwater VLC communications. In this paper, we develop a mathematical framework to evaluate the performance of NOMA-enabled underwater VLC systems in the presence of turbulence. Specifically, we derive a closed-form expression for the outage probability of NOMA over lognormal channels, while considering the effect of path loss and turbulence. The derived analytical results with the corresponding numerical results demonstrate that the transmission distance between laser diode and sensor nodes (SNs) has a high impact on the outage performance of the SNs, due to the increased turbulence level with increased distance. Moreover, the presented results show the effect of the water type on the outage performance of the SNs and on the optimum values of the power coefficients
Automatic identification of roadway horizontal alignment information using geographic information system data: CurvS tool
No full textThis paper introduces CurvS, a web-based tool for researchers and analysts that automatically extracts, visualizes, and analyses roadway horizontal alignment information using readily available geographic information system roadway centerline data. The functionalities of CurvS are presented along with a brief background on its methodology. The validation of its estimation results are presented using actual horizontal alignment data from two different roadway types: Route 83, a two-lane two-way rural roadway in New Jersey and I-80, a freeway segment in Nevada. Different metrics are used for validation. These are identification rates of curved and tangent sections, overlap ratio of curved and tangent sections between estimated and actual horizontal alignment data, and percent fit of curve radii. The validation results show that CurvS is able to identify all the curves on these two roadways, and the estimated section lengths are significantly close to the actual alignment data, especially for the I-80 freeway segment, where 90% of curved length and 94% of tangent section length are correctly matched. Even when curves have small central angles, such as the ones in Route 83, CurvS’s estimations covers 71% of curved length and 96% of tangent section length.NJDOT (FHWA-NJ-2017-001) ; C2SMART, a Tier 1 UTC at New York Universit
Drizzle attenuation model for visible and infrared wavelengths
No full textIn an outdoor environment, the transmitted optical signal is affected by the atmospheric particles that may scatter or absorb light such as drizzle, rain, snow, fog, and aerosols. Various earlier studies have attempted to provide models that accurately describe the attenuation caused by the propagation of light waves through different atmospheric conditions. While the rain attenuation models have received significant research efforts, the modeling of drizzle attenuation was not yet fully studied. In this paper, we conduct extensive simulations in MODTRAN to model drizzle attenuation over the wavelength from 350 nm to 1550 nm. Based on data fitting to simulation results, we further propose a closed-form expression for the drizzle extinction coefficient.TÜBİTA
Nuclear modification of Y states in pPb collisions at √sNN = 5.02 TeV
No full textProduction cross sections of [Formula presented], [Formula presented], and [Formula presented] states decaying into [Formula presented] in proton-lead (pPb) collisions are reported using data collected by the CMS experiment at sNN=5.02TeV. A comparison is made with corresponding cross sections obtained with pp data measured at the same collision energy and scaled by the Pb nucleus mass number. The nuclear modification factor for [Formula presented] is found to be [Formula presented]. Similar results for the excited states indicate a sequential suppression pattern, such that [Formula presented]. The suppression of all states is much less pronounced in pPb than in PbPb collisions, and independent of transverse momentum [Formula presented] and center-of-mass rapidity [Formula presented] of the individual [Formula presented] state in the studied range [Formula presented] and [Formula presented]. Models that incorporate final-state effects of bottomonia in pPb collisions are in better agreement with the data than those which only assume initial-state modifications.BMBWF and FWF (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, FAPERGS, and FAPESP (Brazil); MES and BNSF (Bulgaria); CERN; CAS, MOST, and NSFC (China); MINCIENCIAS (Colombia); MSES and CSF (Croatia); RIF (Cyprus); SENESCYT (Ecuador); MoER, ERC PUT and ERDF (Estonia); Academy of Finland, MEC, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRI (Greece); NKFIA (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); MSIP and NRF (Republic of Korea); MES (Latvia); LAS (Lithuania); MOE and UM (Malaysia); BUAP, CINVESTAV, CONACYT, LNS, SEP, and UASLP-FAI (Mexico); MOS (Montenegro); MBIE (New Zealand); PAEC (Pakistan); MSHE and NSC (Poland); FCT (Portugal); JINR (Dubna); MON, ROSATOM, RAS, RFBR, and NRC KI (Russia); MESTD (Serbia); MCIN/AEI and PCTI (Spain); MoSTR(Sri Lanka); Swiss Funding Agencies (Switzerland); MST (Taipei); ThEPCenter, IPST, STAR, and NSTDA (Thailand); TUBITAK and TAEK (Turkey); NASU (Ukraine); STFC (United Kingdom); DOE and NSF (USA). Individuals have received support from the Marie-Curie program and the European Research Council and Horizon 2020 Grant, contract Nos. 675440, 724704, 752730, 758316, 765710, 824093, 884104, and COST Action CA16108 (European Union); the Leventis Foundation; the Alfred P. Sloan Foundation; the Alexander von Humboldt Foundation; the Belgian Federal Science Policy Office; the Fonds pour la Formation a la Recherche dans l'Industrie et dans l'Agriculture (FRIA-Belgium); the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium); the F.R.S.-FNRS and FWO (Belgium) under the "Excellence of Science -EOS" -be.h project n. 30820817; the Beijing Municipal Science & Technology Commission, No. Z191100007219010; The Ministry of Education, Youth and Sports(MEYS) of the Czech Republic; the Deutsche Forschungsgemeinschaft (DFG), under Germany's Excellence Strategy -EXC 2121 "Quantum Universe" -390833306, and under project number 400140256 -GRK2497; the Lendulet ("Momentum") Program and the Janos Bolyai Research Scholarship of the Hungarian Academy of Sciences, the New National Excellence Program UNKP, the NKFIA research grants 123842, 123959, 124845, 124850, 125105, 128713, 128786, and 129058 (Hungary); the Council of Science and Industrial Research, India; the Latvian Council of Science; the Ministry of Science and Higher Education and the National Science Center, contracts Opus 2014/15/B/ST2/03998 and 2015/19/B/ST2/02861 (Poland); the Fundacao para a Ciencia e a Tecnologia, grant CEECIND/01334/2018 (Portugal); the National Priorities Research Program by Qatar National Research Fund; the Ministry of Science and Higher Education, projects no. 0723-2020-0041 and no. FSWW-2020-0008 (Russia); MCIN/AEI/10.
13039/501100011033, ERDF "a way of making Europe", and the Programa Estatal de Fomento de la Investigacion Cientifica y Tecnica de Excelencia Maria de Maeztu, grant MDM-2017-0765 and Programa Severo Ochoa del Principado de Asturias (Spain); the Stavros Niarchos Foundation (Greece); the Rachadapisek Sompot Fund for Postdoctoral Fellowship, Chulalongkorn University and the Chulalongkorn Academic into Its 2nd Century Project Advancement Project (Thailand); the Kavli Foundation; the Nvidia Corporation; the SuperMicro Corporation; the Welch Foundation, contract C-1845; and the Weston Havens Foundation (USA).Publisher versio
On the development of a novel multi-phase high entropy alloy with transformation-induced plasticity effect
No full textIn the present work, microstructural evolution, and mechanical behavior of a novel high entropy alloy (HEA) are investigated through thermo-mechanical processing. The homogenized samples possess a single-phase cubic structure with high ductility. The rolled and subsequently annealed samples at various treatment conditions exhibit multi-phase microstructures. This study confirms that the sigma phase contribution becomes more significant on the mechanical response at higher annealing temperatures. Effects of phase distribution and degree of recrystallization on the microstructural evolution are examined in detail to probe the variation in the mechanical response. Samples subjected to annealing exhibit transformation-induced plasticity (TRIP) under plastic deformation. As such, the designed TRIP-assisted multi-phase HEA enables a combination of 1 GPa yield strength and about 10% of strain at failure.BAGEP Award of the Science Academy, Turkey ; National Research Foundation of Kore