Optimal ship navigation and algorithms for stochactic obstacle scenes

Tezin basılısı İstanbul Şehir Üniversitesi Kütüphanesi'ndedir.This thesis is comprised of two different but related sections. In the first section, we consider the optimal ship navigation problem wherein the goal is to find the shortest path between two given coordinates in the presence of obstacles subject to safety distance and turn-radius constraints. These obstacles can be debris, rock formations, small islands, ice blocks, other ships, or even an entire coastline. We present a graph-theoretic solution on an appropriately-weighted directed graph representation of the navigation area obtained via 8-adjacency integer lattice discretization and utilization of the A∗ algorithm. We explicitly account for the following three conditions as part of the turn-radius constraints: (1) the ship’s left and right turn radii are different, (2) ship’s speed reduces while turning, and (3) the ship needs to navigate a certain minimum number of lattice edges along a straight line before making any turns. The last constraint ensures that the navigation area can be discretized at any desired resolution. We illustrate our methodology on an ice navigation example involving a 100,000 DWT merchant ship and present a proof- of-concept by simulating the ship’s path in a full-mission ship handling simulator at Istanbul Technical University. In the second section, we consider the stochastic obstacle scene problem wherein an agent needs to traverse a spatial arrangement of possible-obstacles, and the status of the obstacles may be disambiguated en route at a cost. The goal is to find an algorithm that decides what and where to disambiguate en route so that the expected length of the traversal is minimized. We present a polynomial-time method for a graph-theoretical version of the problem when the associated graph is restricted to parallel avenues with fixed policies within the avenues. We show how previously proposed algorithms for the continuous space version can be adapted to a discrete setting. We propose a gener- alized framework encompassing these algorithms that uses penalty functions to guide the navigation in realtime. Within this framework, we introduce a new algorithm that provides near-optimal results within very short execution times. Our algorithms are illustrated via computational experiments involving synthetic data as well as an actual naval minefield data set. Keywords: Graph theory, shortest path, ship navigation, probabilistic path planning, stochastic dynamic programming, Markov decision process, Canadian traveler’s problemContents Declaration of Authorship ii Abstract iv ¨ Oz v Acknowledgments vii List of Figures x List of Tables xi 1 Optimal Ship Navigation with Safety Distance and Realistic Turn Con- straints 1 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Previous Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 The Optimal Ship Navigation Problem . . . . . . . . . . . . . . . . . . . . 4 1.4 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4.1 Safety Distance Constraints . . . . . . . . . . . . . . . . . . . . . . 5 1.4.2 Lattice Discretization . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4.3 Ship-Turn Constraints . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.4.4 The A∗ Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.4.5 Smoothing the Optimal Path . . . . . . . . . . . . . . . . . . . . . 13 1.5 Ice Navigation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.6 Simulator Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.7 Summary, Conclusions, and Future Research . . . . . . . . . . . . . . . . 18 2 Algorithms for Stochastic Obstacle Scenes 21 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.2 The Stochastic Obstacle Scene Problem: Continuous vs. Discrete Settings 23 2.2.1 Deciding Where to Disambiguate: Single Disk Case . . . . . . . . 23 2.2.2 Deciding Where to Disambiguate: Two Disks Case . . . . . . . . . 25 2.2.3 Discretization of the Continuous Setting: An Example . . . . . . . 27 2.3 Definition of the Stochastic Obstacle Scene Problem . . . . . . . . . . . . 27 2.3.1 Continuous SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.2 Discrete SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.3 Discretized SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.4 A Polynomial Algorithm for Discrete SOSP on Parallel Graphs . . . . . . 29 2.5 Discrete Adaptation of the Simulated Risk Disambiguation Algorithm . . 30 2.5.1 Adaptation to Discrete SOSP . . . . . . . . . . . . . . . . . . . . . 30 2.5.2 Adaptation to Discretized SOSP . . . . . . . . . . . . . . . . . . . 32 2.6 Discrete Adaptation of the Reset Disambiguation Algorithm . . . . . . . . 33 2.7 Generalizing SRA and RDA: Penalty-Based Algorithms and DTA . . . . . 34 2.7.1 Illustration of the Algorithms . . . . . . . . . . . . . . . . . . . . . 36 2.8 Computational Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.8.1 Environment A (The COBRA Data) Experiments . . . . . . . . . 40 2.8.2 Environment B Experiments . . . . . . . . . . . . . . . . . . . . . 41 2.8.3 Environment C Experiments . . . . . . . . . . . . . . . . . . . . . 43 2.9 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 A Impact of Cost Change in Parallel Graphs 47 Bibliograph

The effect of varenicline on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio in healthy smokers and nonsmokers

Background: Varenicline could affect the T wave and QT interval. The interval from the peak to the end of the electrocardiographic (ECG) T wave (Tp-e) may correspond to the transmural dispersion of repolarization, and increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. In this study, we assessed the effects of varenicline on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio. Methods: Thirty healthy volunteers (15 healthy non-smokers [NS] and 15 healthy smokers [S]) were included in the randomized, double-blind, placebo-controlled, crossover study. Varenicline (2 mg single dose) or placebo was administered in two different testing sessions (5 days after the first period, performed the second period). Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were assessed in the supine position and during handgrip exercise before and after the participants were given placebo or varenicline. Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were calculated from continuous ECG recordings and averages were used in the final analysis. Result: There were no statistically significant differences among any of the Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio before and after placebo administration in both groups (S and NS). In the S group, Tp-e and QTc interval, and Tp-e/QT and Tp-e/QTc ratio were significantly increased after varenicline administration (Tp-e: 64.28 ± 8.78 vs. 70.42 ± ± 13.12; p = 0.02, QTc: 409.57 ± 28.17 vs. 425.28 ± 32.79; p = 0.02, Tp-e/QT: 0.18 ± 0.02 vs. 0.19 ± 0.03; p = 0.04, Tp-e/QTc: 0.17 ± 0.02 vs. 0.19 ± 0.02; p = 001) but these parameters were not changed in the NS group. Conclusions: Tp-e and QTc interval, and Tpe/QT and Tpe/QTc ratio were increased after varenicline administration in smoker

Optimal ship navigation and algorithms for stochactic obstacle scenes

This thesis is comprised of two different but related sections. In the first section, we consider the optimal ship navigation problem wherein the goal is to find the shortest path between two given coordinates in the presence of obstacles subject to safety distance and turn-radius constraints. These obstacles can be debris, rock formations, small islands, ice blocks, other ships, or even an entire coastline. We present a graph-theoretic solution on an appropriately-weighted directed graph representation of the navigation area obtained via 8-adjacency integer lattice discretization and utilization of the A∗ algorithm. We explicitly account for the following three conditions as part of the turn-radius constraints: (1) the ship’s left and right turn radii are different, (2) ship’s speed reduces while turning, and (3) the ship needs to navigate a certain minimum number of lattice edges along a straight line before making any turns. The last constraint ensures that the navigation area can be discretized at any desired resolution. We illustrate our methodology on an ice navigation example involving a 100,000 DWT merchant ship and present a proof- of-concept by simulating the ship’s path in a full-mission ship handling simulator at Istanbul Technical University. In the second section, we consider the stochastic obstacle scene problem wherein an agent needs to traverse a spatial arrangement of possible-obstacles, and the status of the obstacles may be disambiguated en route at a cost. The goal is to find an algorithm that decides what and where to disambiguate en route so that the expected length of the traversal is minimized. We present a polynomial-time method for a graph-theoretical version of the problem when the associated graph is restricted to parallel avenues with fixed policies within the avenues. We show how previously proposed algorithms for the continuous space version can be adapted to a discrete setting. We propose a gener- alized framework encompassing these algorithms that uses penalty functions to guide the navigation in realtime. Within this framework, we introduce a new algorithm that provides near-optimal results within very short execution times. Our algorithms are illustrated via computational experiments involving synthetic data as well as an actual naval minefield data set.Declaration of Authorship ii Abstract iv ¨ Oz v Acknowledgments vii List of Figures x List of Tables xi 1 Optimal Ship Navigation with Safety Distance and Realistic Turn Con- straints 1 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.2 Previous Work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.3 The Optimal Ship Navigation Problem . . . . . . . . . . . . . . . . . . . . 4 1.4 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.4.1 Safety Distance Constraints . . . . . . . . . . . . . . . . . . . . . . 5 1.4.2 Lattice Discretization . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.4.3 Ship-Turn Constraints . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.4.4 The A∗ Algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 1.4.5 Smoothing the Optimal Path . . . . . . . . . . . . . . . . . . . . . 13 1.5 Ice Navigation Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.6 Simulator Application . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 1.7 Summary, Conclusions, and Future Research . . . . . . . . . . . . . . . . 18 2 Algorithms for Stochastic Obstacle Scenes 21 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 2.2 The Stochastic Obstacle Scene Problem: Continuous vs. Discrete Settings 23 2.2.1 Deciding Where to Disambiguate: Single Disk Case . . . . . . . . 23 2.2.2 Deciding Where to Disambiguate: Two Disks Case . . . . . . . . . 25 2.2.3 Discretization of the Continuous Setting: An Example . . . . . . . 27 2.3 Definition of the Stochastic Obstacle Scene Problem . . . . . . . . . . . . 27 2.3.1 Continuous SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.2 Discrete SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.3 Discretized SOSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 2.4 A Polynomial Algorithm for Discrete SOSP on Parallel Graphs . . . . . . 29 2.5 Discrete Adaptation of the Simulated Risk Disambiguation Algorithm . . 30 2.5.1 Adaptation to Discrete SOSP . . . . . . . . . . . . . . . . . . . . . 30 2.5.2 Adaptation to Discretized SOSP . . . . . . . . . . . . . . . . . . . 32 2.6 Discrete Adaptation of the Reset Disambiguation Algorithm . . . . . . . . 33 2.7 Generalizing SRA and RDA: Penalty-Based Algorithms and DTA . . . . . 34 2.7.1 Illustration of the Algorithms . . . . . . . . . . . . . . . . . . . . . 36 2.8 Computational Experiments . . . . . . . . . . . . . . . . . . . . . . . . . . 37 2.8.1 Environment A (The COBRA Data) Experiments . . . . . . . . . 40 2.8.2 Environment B Experiments . . . . . . . . . . . . . . . . . . . . . 41 2.8.3 Environment C Experiments . . . . . . . . . . . . . . . . . . . . . 43 2.9 Summary and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 A Impact of Cost Change in Parallel Graphs 47 Bibliograph

Can economic and financial development curb CO2 emissions in Qatar?

This study investigates the impacts of economic and financial development on carbon emissions in Qatar between 1975 and 2018 by analyzing the results of the ARDL and VECM tests. We do so by considering two model specifications, Model 1 and 2, considering CO2 emission is a dependent variable. In Model 1, economic growth and its square are considered as independent variables to test the basic Environmental Kuznets Curve (EKC) hypothesis. The results provide evidence to confirm the EKC hypothesis for Qatar. In Model 2, various economic and financial variables are specified as regressors, and all the independent variables have a statistically significant impact on CO2 emissions at a 1% level. The coefficient of real income per capita implies that an increase in income will increase carbon emissions by 72%. On the other hand, financial development's carbon elasticity indicates that an increase in financial development will decrease CO2 emissions by 32%. The carbon elasticity of foreign trade signifies that an increase in trade will decrease CO2 emissions by 33%

Hemşirelik ve Ebelik Öğrencilerinin HIV/AIDS’e İlişkin Bilgi Düzeylerinin ve Tanı Almış Kişilere Yaklaşımlarının Belirlenmesi

Amaç: Bulaşıcı hastalıklar içerisinde yaygınolarak görülen HIV/AIDS, kişilerin yaşamkalitelerini düşüren ve hemen hemen her yaşgrubunda görülebilen önemli bir halk sağlığısorunudur. Ulusal ve uluslararası alanda yapılançalışmalar, sağlık profesyonellerinin; özelliklehemşire ve ebelerin HIV/AIDS’e yönelik bilgidüzeylerinin yeterli olmadığını göstermektedir. Buçalışmanın amacı hemşirelik ve ebelik bölümüöğrencilerinin HIV/AIDS’e ilişkin bilgi düzeylerinive tanı almış kişilere yaklaşımlarını belirlemektir.Gereç-yöntem:&nbsp;Tanımlayıcı tipteki araştırmadaörneklem seçimine gidilmemiş, araştırmayürütüldüğü esnada okulda olan ve araştırmakatılmayı kabul eden 346 öğrenci örneklemioluşturmuştur. Veriler, araştırmacılar tarafındanliteratürden yararlanarak hazırlanan Kişisel BilgiFormu ve HIV/AIDS’e İlişkin Tutum ve DavranışDeğerlendirme Formu kullanılarak toplanmıştır.Verilerin analizinde yüzdelik hesaplamalar, Kikare ve Kruskall Wallis testinden yararlanılmıştır.Bulgular: Çalışmamızda öğrencilerin %31,2’siebelik, %68,8’si hemşirelik bölümündeokumaktadır. Öğrencilerin HIV/AIDS bilgi anketipuan ortalaması 11.11±3.02 olarak bulunmuş veBirinci sınıfta okuyan öğrencilerin bilgi düzeyipuan ortalamalarının diğer sınıflara göre anlamlıderecede düşük olduğu görülmüştür.&nbsp;Sonuç: Öğrenciler HIV/AIDS’e yönelik ortadüzeyde bilgi sahibidir. Tüm dünyadaHIV/AIDS’in yaygınlaşmasını önlemenin yolueğitimden geçmektedir. Eğitim de öncelikli olarak&nbsp;geleceğin sağlık profesyonelleri olan hemşirelik veebelik öğrencilerine verilmelidir.Anahtar Sözcükler: HIV/AIDS; Bilgi; Yaklaşım;Öğrenci.Objective: HIV / AIDS, which is common amonginfectious diseases, is an important public healthproblem that decreases the quality of life ofindividuals and can be seen in almost all agegroups. National and international studies, healthprofessionals; In particular, it shows that nursesand midwives have insufficient knowledge of HIV /AIDS The aim of this study is to determine theknowledge level of nursing and midwifery studentsabout HIV / AIDS and their approach to diagnosedpeople.Materials and methods: In the descriptive study,no sample selection was made, and 346 studentswho were in school and accepted to participate inthe study constituted the sample. Data werecollected by using Personal Information Form andAttitude and Behavior Assessment Form for HIV /AIDS prepared by researchers using literature. Inthe analysis of the data, percentage calculations,Chi-square and Kruskall Wallis test were used.Results: In our study, 31.2% of the students werestudying in midwifery and 68.8% were studying innursing department. The mean score of the HIV /AIDS knowledge questionnaire of the students wasfound to be 11.11 ± 3.02 and it was found that theaverage level of knowledge level of the students inthe first grade was significantly lower than theother grades.&nbsp;Conclusion: Students have moderate knowledge ofHIV / AIDS. Education is the way to prevent thespread of HIV / AIDS worldwide. Education shouldbe given primarily to nursing and midwiferystudents who are health professionals of the future.Keywords: HIV/AIDS; information; approach;student.</p

A Content Analysis of Developmental Psychology Sections of Educational Psychology Textbooks Used For Teachers' Education in Turkey

The purpose of this study was to examine the developmental psychology sections of the most commonly used educational psychology textbooks with respect to; their use of politically correct language, epistemological styles, breath/depth of content, scope and utilization of up to date information. Content analysis was used to examine the textbooks. Results showed that the existing textbooks significantly lacked concern about non-discriminative/politically correct language; they were places in dualism; content typically introduced basic concepts and classic developmental theories. Findings, limitations of the study and implications for future studies and teachers education were discussed. (C) 2009 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Dr. Zafer Bekirogullari of Y.B.WoSScopu

The effect of agomelatine on the nociceptive system

Amaç: Bu araştırmanın amacı bir antidepresan olan agomelatinin nosiseptif sistem üzerindeki etkisini ortaya çıkarmaktır. Yöntem: Bu amaçla, 24 Swiss albino erkek fare (4 aylık ve 28.8±1.18 g ağırlığında) random olarak eşit sayıda farelerden oluşan üç gruba, A Grubu, B Grubu ve kontrol grubu olan C Grubu olarak ayrıldı. A Grubu'na 12.5 mg/kg agomelatin, B Grubu'na 25 mg/kg agomelatin ve C Grubu'na salin intraperitoneal yol ile verildi. Nosiseptif etkiyi değerlendirmek için hot plate metodu (50ºC) kullanılarak kontrol ve agomelatin gruplarına ait ağrı eşik değerleri 30. ve 60. dakika bulguları olarak kaydedildi. Bulgular: Ağrı eşiği sonuçlarına göre agomelatin gruplarına ait veriler her iki zamanda da kontrol grubundan daha yüksek olarak bulundu. 30. dakika ölçümlerinde B grubu ile diğer gruplar arasında anlamlı farklılık gözlendi (p=0.007). Aynı zamanda grupların zamanla etkileşiminde de anlamlılık gözlendi (p=0.036). Sonuçlar: Bu çalışmanın sonuçları agomelatinin farelerde nosiseptif sistem üzerinde analjezik etkinliğinin olabileceğini ortaya koymaktadırThe effect of agomelatine on the nociceptive syste

Zoster‑associated Limb Paralysis: Clinical and Electrophysiological Data of 15 Cases with Segmental Zoster Paresis with the Literature Review

Background: Herpes zoster (HZ) is a viral disease characterized by skin eruptions and pain in specific dermatomes. Focal motor weakness that appears in the segment of skin eruptions is a rare complication of this infection. Because of the difficulty in clinically diagnosing thoracic or upper cervical motor weakness and due to the pain that causes overlooking of weakness, the true incidence of this complication is not known. In this study, we want to review the clinical presentation of segmental zoster paresis and also discuss electrophysiological findings with the involvement of nerve, plexus parts, or spinal roots. Methods: Electromyography records were examined retrospectively from 2010 to 2023 for patients who had HZ‑associated limb paresis. Clinical data were reviewed and abstracted, and patients whose clinical limb weakness and sensory deficits conformed to the distribution of peripheral nerve (s) or spinal root and whose electrodiagnostic evaluation corroborated the localization, were included in the series. Results: Fifteen patients were included in our study. Ten of them were men and five of them were women. Paresis and neuropathic pain are the main complaints. In all patients, the distribution of paresis was consistent with the area of skin eruptions. C8–T1 in the upper extremity and L5–S1 in the lower extremity are the most commonly involved segments. Electrophysiological findings showed radicular involvement in three cases, brachial plexus in six cases, ulnar nerve in one case, sciatic nerve in two cases, and fibular nerve in three cases. Axonopathy is the main detected pathology in all cases. Conclusion: Segmental zoster paresis is a rare complication of cutaneous zona zoster and it affects different nerve segments. Clinicians should be aware of clinical and electrophysiological findings of this disease for the appropriate management of the patients