Wavelet based similarity measurement algorithm for seafloor morphology

Thesis (S.M. in Naval Architecture and Marine Engineering and S.M. in Mechanical Engineering)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2006.Includes bibliographical references (leaves 71-73).The recent expansion of systematic seafloor exploration programs such as geophysical research, seafloor mapping, search and survey, resource assessment and other scientific, commercial and military applications has created a need for rapid and robust methods of processing seafloor imagery. Given the existence of a large library of seafloor images, a fast automated image classifier algorithm is needed to determine changes in seabed morphology over time. The focus of this work is the development of a robust Similarity Measurement (SM) algorithm to address the above problem. Our work uses a side-scan sonar image library for experimentation and testing. Variations of an underwater vehicle's height above the sea floor and of its pitch and roll angles cause distortion in the data obtained, such that transformations to align the data should include rotation, translation, anisotropic scaling and skew. In order to deal with these problems, we propose to use the Wavelet transform for similarity detection. Wavelets have been widely used during the last three decades in image processing. Since the Wavelet transform allows a multi-resolution decomposition, it is easier to identify the similarities between two images by examining the energy distribution at each decomposition level.(cont.) The energy distribution in the frequency domain at the output of the high pass and low pass filter banks identifies the texture discrimination. Our approach uses a statistical framework, involving fitting the Wavelet coefficients into a generalized Gaussian density distribution. The next step involves use of the Kullback-Leibner entropy metric to measure the distance between Wavelet coefficient distributions. To select the top N most likely matching images, the database images are ranked based on the minimum Kullback-Leibner distance. The statistical approach is effective in eliminating rotation, mis-registration and skew problems by working in the Wavelet domain. It's recommended that further work focuses on choosing the best Wavelet packet to increase the robustness of the algorithm developed in this thesis.by Ilkay Darilmaz.S.M.in Naval Architecture and Marine Engineering and S.M.in Mechanical Engineerin

An assumed stress hybrid element for analysis of plates

Gerilme seçimli hibrid sonlu eleman yöntemi, eleman içinde denge denklemlerini sağlayan gerilme alanı seçimi ile eleman sınırlarında uyumlu yer değiştirmelerin seçimi ilkesine dayanmaktadır. Çalışmada ince ve orta kalınlıkta plakların çözümü için 8 noktalı, genel biçimli, gerilme seçimli hibrid bir dörtgen plak sonlu eleman geliştirilmiştir. Formulasyon Hellinger-Reissner ilkesi esas alınarak elde edilmiştir. Eleman her düğüm noktasında üç adet olmak üzere toplam 24 serbestlik derecesi içermektedir. Elemanın geliştirilmesinde kalınlık doğrultusunda kayma şekil değiştirmelerinin etkisini de göz önüne almak için Reissner-Mindlin plak teorisi esas alınmıştır. Geliştirilen eleman ile literatürdeki çalışmalarda bulunan çeşitli örnekler çözülmüş ve uyumlu sonuçlar elde edilmiştir.Anahtar Kelimeler: Hibrid sonlu eleman yöntemi, plak, statik hesap.Finite element method, models a structure as an assemblage of small elements. An important ingredient in a finite element analysis is the behavior of the individual element. In displacement based finite element, formulation of element stiffness matrix depends on interelement-compatible displacement field interpolation. Finite element method based on the assumed-stress hybrid method is a way of formulating a stiffness matrix by use of independent assumptions of an equilibrium stress field within the element and interelement compatible displacement modes on the element boundary. Mathematically the method can be stated as  a modified complementary energy principle. In this study an 8-node quadrilateral assumed-stress hybrid plate element is presented. The Element has eight nodes and twenty four degrees of freedom. At each node of the element one displacement and two rotations are taken as unknowns. The element uses the Reissner-Mindlin plate theory, which takes into account the transverse shear effects. To check the the accuracy of the finite element, various examples are solved numerically and compared with the other element solutions . The results obtained from numerical examples demonstrate that the element alleviates the locking phenomenon and produces accurate solutions, has desirable convergence which are in a good agreement with other state-of-the-art element solutions.Keywords: Hybrid finite element method, plate, static analysis

Checklist of the Hydraenidae (Coleoptera) of Turkey, with notes on distribution

A checklist of the Hydraenidae recorded from Turkey is presented. The checklist includes data on the distribution and relevant references for 210 species/subspecies: two Aulacochthebius Leach, 113 Hydraena Kugelann, 21 Limnebius Leach, and 74 Ochthebius Leach. On the basis of their current distribution, the established 210 species/subspecies can be classified into 28 zoogeographical categories, grouped into six complexes. The largest number of species belongs to the group of Turkey endemics (49.05 %), which reflects the local character of the fauna. Copyright © 2011 · Magnolia Press

Buckling and vibration analysis of laminated composite plate/shell structures via a smoothed quadrilateral flat shell element with in-plane rotations

This paper presents buckling and free vibration analysis of composite plate/shell structures of various shapes, modulus ratios, span-to-thickness ratios, boundary conditions and lay-up sequences via a novel smoothed quadrilateral flat element. The element is developed by incorporating a strain smoothing technique into a flat shell approach. As a result, the evaluation of membrane, bending and geometric stiffness matrices are based on integration along the boundary of smoothing elements, which leads to accurate numerical solutions even with badly-shaped elements. Numerical examples and comparison with other existing solutions show that the present element is efficient, accurate and free of locking

Importance of Labarotory Parameters in Obstructive Sleep Apnea

Objective Obstructive sleep apnea (OSA) is associated with intermittent hypoxia. OSA leads to increased sympathetic activation, oxidative stress, vascular endothelial dysfunction, coagulation disorders and metabolic dysregulation. These disturbances increase the the risk of inflammation and cardiovascular diseases. The purpose of this article is to review the laboratory parameters of OSA patients without any comorbidities. Materials and Methods This retrospective study of consecutive 675 patients who had polysomnography, was conducted on one hundred and thirty patients who did not have any comorbidities. Laboratory values of patients were evaluated. Patients were grouped according to apnea-hypopnea index (AHI). Group 1 (n=17) AHI 30. Results There were 88 men (67.7%) and 42 women (32.3%) in the study. Mean age, body mass index, Epworth score and AHI were 41.6±11.3 (16-75), 29.6±6.3 (17.1-65.7) 9.9±5.5, 6.2±11.34, respectively. Serum glucose, cholesterol and triglyceride levels were higher in group 4 (p=0.03, p=0.04, p=0.02, respectively). Uric acid and fibrinogen levels were higher in patients with higher AHI (p=0.038). Conclusion Our study indicates that increased blood glucose, uric acid and dyslipidemia are associated with OSA regardless of comorbidities

Investigation of aliphatic hydrocarbons in red mullet (Mullus barbatus) and European hake (Merluccius merluccius) fish caught from the Edremit Bay (Western Turkey)

In this study, aliphatic hydrocarbon levels were investigated in red mullet and european hake fish caught by trawler from Edremit Bay (Western Aegean, Turkey) in spring and autumn 2015. For this purpose, trawling was carried out from 3 different regions of the Edremit Bay in both seasons. As a result of the analyzes, total aliphatic hydrocarbon (TAH) levels in red mullet were found to be higher than that of european hake. TAH concentrations found for red mullet were in the range of 456-2090 ng/g, while it was found in the range of 61-746 ng/g for european hake. In general, TAH concentrations in red mullet were higher than that of european hake for both seasons. In addition, EOM amounts were found higher in red mullet like TAH. According to correlation, cluster and primary component analysis results, it was observed that the compounds affecting TAH levels in red mullet are C11 and C12 aliphatic hydrocarbon compounds, while european hake have C15, C17 and Pristane compounds. These results indicate that the source of aliphatic hydrocarbons in Edremit Bay fish is biogenic in european hake samples, although not exact, it may be petrogenic in red mullet samples

Aliphatic hydrocarbons in coastal sediments of the Northern Cyprus (Eastern Mediterranean)

The sources and spatial distributions of aliphatic hydrocarbon concentrations were investigated in surficial sediments of the Northern Cyprus (Gemi Konagi, Girne and Gazi Magusa Areas). Aliphatic hydrocarbon levels were determined with a gas chromatography-mass spectrometer. Total aliphatic hydrocarbon (n-alkanes, Sigma 25; isoprenoids, Sigma 2) concentrations in the sediments were found in the range of 1107-6360 ng/g. Results indicated that the sediments were mainly dominated by odd numbered n-alkanes (n-C10-n-C34), maximizing at n-C17, n-C29 and n-C31. Statistical analyses and diagnostic ratios have been used to determine the possible sources and origins of aliphatic hydrocarbons. Aliphatic hydrocarbons were showed biogenic character at all sampling areas and were found mainly originated from terrestrial, marine and both terrestrial-marine plants at Gemi Konagi, Gazi Magusa and Girne, respectively

İzmir Körfezi'nden seçilen balık türlerinde alifatik ve polisiklik aromatik hidrokarbon seviyelerinin değerlendirilmesi

Bu tezde İzmir Körfezi'nden trolle yakalanmış olan barbun (Mullus barbatus) ve isparoz (Diplodus annularis) balıklarında ilk defa detaylı olarak polisiklik aromatik hidrokarbonlar (PAHs) ve alifatik hidrokarbonlar analiz edilmiştir. Körfezde sıklıkla bulunması ve tüketilmesi nedeniyle bu türler seçilmiştir. Örnekler trolle körfezdeki beş bölgeden 2000-2001 ve 2004-2005 yıllarında mevsimsel olarak toplanmış ve analiz edilmiştir. Naftalen polisiklik aromatic hidrokarbonlar içinde en baskın bileşiktir. Barbundaki PAH ve alifatik hidrokarbon konsantrasyonları isparozdan daha yüksek bulunmuştur. PAH konsantrasyonları barbun ve isparoz balıklarında sırasıyla 202-556 ile 78,7-415 ng/g, alifatik hidrokarbonlar ise 834-2420 ile 436-1724 ng/g kuru ağırlık aralığında ölçülmüştür. İzmir Körfezi'ndeki balıklarda ölçülmüş olan PAHs ve alifatik hidrokarbonların kaynaklarını belirlemek amacıyla moleküler oranlar kullanılmış olup PAHs'ın pirolitik, alifatiklerin ise biyojenik ve antropojenik kaynaklı olduğu bulunmuştur. Balıkların çoğunluğunda kanserojenik özelliği olan Benzo(a)Piren bileşiği 22,2 ile 64,1 ng/g kuru ağırlık aralığında ölçülmüştür. Yapılan istatiksel analiz sonucunda ekstrakte edilebilen organic madde ile PAHs ve alifatik hidrokarbonların arasında bir ilişki bulunmamıştır. Barbun ve isparozda zamana bağlı olarak alifatik hidrokarbon konsantrasyonlarında anlamlı bir değişim bulunmaz iken barbunda PAH konsantrasyonlarında zamana bağlı anlamlı bir değişim ANOVA testi ile saptanmıştır. İzmir Körfezi'ndeki PAH kirlenmesi orta seviyededir. Sonuçlar insan sağlığı için doğru bir yaklaşım ve risk değerlendirmesi açısından sistematik olarak izlenmenin gerekliliğini işaret etmektedir. In this thesis, polycyclic aromatic hydrocarbons (PAHs) and aliphatic hydrocarbons were analyzed in red mullet (Mullus barbatus) and in annular sea bream (Diplodus annularis) from Izmir Bay (Eastern Aegean). This is the first time that a complete set of such data has been collected and evaluated. These species were selected because of they are common, widely distributed and eaten. They were sampled by trawling and analyzed seasonally in 2000-2001 and in 2004-2005 at five locations. Naphthalene was found to be the dominant PAH. Red mullet showed higher concentrations of PAHs and aliphatics than annular sea bream. PAH levels in red mullet ranged from 202 to 556 ngg-1dw and in annular sea bream from 78.7 to 415; aliphatics levels ranged from 834 to 2420 and from 436 to 1724 ngg-1dw, respectively. The molecular ratios, used to identify sources of PAHs and aliphatics in fish of the Izmir Bay, showed pyrolitic inputs for PAHs, but biogenic and anthropogenic inputs for aliphatics. Carcinogenic Benzo(a)Pyrene was detected in most fish samples at levels between 22.2 and 64.1 ngg-1dw. Statistical analysis showed no correlation of PAHs and aliphatics regarding extractable organic matter (HEOM). No significant temporal, inter-species, differences for total aliphatics was shown by the ANOVA test; a significant, temporal, PAHs difference was detected for red mullet. The average Izmir Bay PAH contamination level was within the ?moderate? category. Results indicate the need for systematic monitoring of the study area, in order to provide accurate assessment and risk management for human health