Mobile robot navigation: issues in implementating the generalized Voronoi graph in the plane

This paper describes the procedures that are required to implement, on a conventional mobile robot, a sensor based motion planning algorithm based on the generalized Voronoi graph (GVG). The GVG is a roadmap of a static environment, and we describe how to incrementally construct this roadmap using only range information in an unknown environment. The GVG may then be used to guide future excursions into the explored environment. Experimental results validate the utility of this work

Mobile robot navigation: issues in implementating the generalized Voronoi graph in the plane

This paper describes the procedures that are required to implement, on a conventional mobile robot, a sensor based motion planning algorithm based on the generalized Voronoi graph (GVG). The GVG is a roadmap of a static environment, and we describe how to incrementally construct this roadmap using only range information in an unknown environment. The GVG may then be used to guide future excursions into the explored environment. Experimental results validate the utility of this work

Elektron Işınıyla Ergitme Yöntemiyle Üretilen Ti6Al4V Parçalarının Mekanik Özellikleri Üzerinde İnşa Yönünün Etkisi

The aim of this study is to investigate the effect of building direction on mechanical properties of the parts fabricated using Ti6Al4V alloy powders by electron beam melting method. Three specimens in three different directions (X, Y and Z) were produced and to see the effect of surface roughness on mechanical properties, one of the samples in each direction were machined by lathe. The results of tension tests on samples produced in three directions according to ASTM E8 standard revealed that yield and tensile strength of the samples built in Z direction are higher than the related properties of the samples built in X and Y directions. Yield and tensile strength of the samples built in each of the direction comes out to be higher than the same properties of the wrought or cast Ti6Al4V parts. Specimens displayed a mixed ductile-brittle fracture characteristic and the microstructure is mainly Widmanstatten / basket weave and α lamellar microstructure was observed inside the prior β grains

A European perspective on auditory processing disorder-current knowledge and future research focus

Current notions of \u201chearing impairment,\u201d as reflected in clinical audiological practice, do not acknowledge the needs of individuals who have normal hearing pure tone sensitivity but who experience auditory processing difficulties in everyday life that are indexed by reduced performance in other more sophisticated audiometric tests such as speech audiometry in noise or complex non-speech sound perception. This disorder, defined as \u201cAuditory Processing Disorder\u201d (APD) or \u201cCentral Auditory Processing Disorder\u201d is classified in the current tenth version of the International Classification of diseases as H93.25 and in the forthcoming beta eleventh version. APDs may have detrimental effects on the affected individual, with low esteem, anxiety, and depression, and symptoms may remain into adulthood. These disorders may interfere with learning per se and with communication, social, emotional, and academic-work aspects of life. The objective of the present paper is to define a baseline European APD consensus formulated by experienced clinicians and researchers in this specific field of human auditory science. A secondary aim is to identify issues that future research needs to address in order to further clarify the nature of APD and thus assist in optimumdiagnosis and evidence-based management. This European consensus presents the main symptoms, conditions, and specific medical history elements that should lead to auditory processing evaluation. Consensus on definition of the disorder, optimum diagnostic pathway, and appropriate management are highlighted alongside a perspective on future research focus

Interactive Learning Management System to Develop Spatial Visualization Abilities

An Interactive Learning Management System (ILMS) is presented, which functions as a web-based Spatial Visualization Ability (SVA) learning support tool for students of engineering graphics and as a management tool for teachers to track student learning. This software is designed to fill the gaps in student knowledge, giving them more uniform spatial visualization abilities when enrolling on University Engineering degrees. The ILMS_SVA consists of: (1) a Content Management System (CMS); (2) a preliminary level assessment test; (3) a web-based tool for exercise management and self-assessment incorporating a 3D viewer that functions as an interactive tutorial (IT), allowing the manipulation of 3D objects in every exercise; (4) a database. It is designed for three types of users (student, teacher, and administrator), and has been validated with engineering graphics students at the University of Burgos (Spain) by means of experimental trials in the classroom and a user satisfaction survey, over two academic years. The results indicate that use of this tool improved SVA among students generally and was even of greater effectiveness for those students that accessed engineering courses with no prior knowledge of Technical Drawing

A European Perspective on Auditory Processing Disorder-Current Knowledge and Future Research Focus

Current notions of “hearing impairment,” as reflected in clinical audiological practice, do not acknowledge the needs of individuals who have normal hearing pure tone sensitivity but who experience auditory processing difficulties in everyday life that are indexed by reduced performance in other more sophisticated audiometric tests such as speech audiometry in noise or complex non-speech sound perception. This disorder, defined as “Auditory Processing Disorder” (APD) or “Central Auditory Processing Disorder” is classified in the current tenth version of the International Classification of diseases as H93.25 and in the forthcoming beta eleventh version. APDs may have detrimental effects on the affected individual, with low esteem, anxiety, and depression, and symptoms may remain into adulthood. These disorders may interfere with learning per se and with communication, social, emotional, and academic-work aspects of life. The objective of the present paper is to define a baseline European APD consensus formulated by experienced clinicians and researchers in this specific field of human auditory science. A secondary aim is to identify issues that future research needs to address in order to further clarify the nature of APD and thus assist in optimum diagnosis and evidence-based management. This European consensus presents the main symptoms, conditions, and specific medical history elements that should lead to auditory processing evaluation. Consensus on definition of the disorder, optimum diagnostic pathway, and appropriate management are highlighted alongside a perspective on future research focus

Investigation of RTK Performance Using Active Global Navigation Satellite Systems

Yüksek Lisans TeziKüresel Navigasyon Uydu Sistemi (GNSS), kullanıcılara hızlı, uygun maliyetli ve güvenilir bir konum belirleme hizmeti sağlamaktadır. Gerçek zamanlı kinematik (RTK) yöntemi birçok mühendislik uygulamasında gerçek zamanlı konumlama için pratik bir araç haline gelmiştir. RTK yönteminin doğruluğu, yörünge hatası ve atmosferik hatalar nedeniyle referans istasyonu ile gezici arasındaki baz mesafesine bağlıdır. Ayrıca günümüzde RTK düzeltmeleri internet protokollerinin gelişimiyle birlikte GSM üzerinden iletilebilmekte olup radyo modemden kaynaklanan mesafe sınırlandırılması da ortadan kalkmıştır. RTK ölçmeleri genel olarak GPS ve GLONASS uydu sistemleri kullanılarak gerçekleştirilmektedir. Ancak günümüzde GALILEO ve BEIDOU gibi yeni GNSS sistemleri de kullanıcıların hizmetine sunulmuştur. Bu tez çalışmasında internet tabanlı klasik RTK yöntemi kullanılarak çoklu GNSS kombinasyonlarının performansını test etmek amacıyla farklı baz mesafeleri (~20, ~40, ~60, ~80 km) dikkate alınarak, Konya’da arazi çalışmaları yapılmıştır. Ölçüm yapılan noktalarda eşit koşullara sahip 3 gezici alıcı kullanılarak sadece GPS, GPS+GLONASS, GPS+GLONASS+GALILEO+BEIDOU uydu konfigürasyonlarında ölçümler yapılmıştır. RTK koordinatları farklı uydu konfigürasyonları ile her uygulama noktasında yaklaşık 9 saat olmak üzere 10°, 20° ve 30° yükseklik açılarında üç oturum şeklinde elde edilmiştir. Her uygulama noktasında ilk oturumlarda (10°) yaklaşık 5 saatlik RTK ölçümlerinin yanı sıra statik veri kaydı da alınmıştır. Gezici alıcıların gerçek koordinatları, statik verilerin GAMIT/GLOBK akademik yazılımı kullanılarak, bağıl yöntemle değerlendirilmesiyle elde edilmiştir. Elde edilen sonuçlar tekrarlılık ve doğruluk açısından değerlendirilmiştir. Çoklu GNSS kombinasyonlarının 10° uydu yükseklik açısında RTK performansını tekrarlılık açısından iyileştirdiği görülmüştür. Yalnız GPS çözümlerinin doğruluğu yatay ve düşey bileşenler için sırasıyla 0.63/2.17cm ve 2.40/4.94cm arasında değişmiştir. Ancak RTK yöntemi için çoklu GNSS kombinasyonlarının, yalnız GPS’e göre uydu yükseklik açısı 30° seçildiğinde bile doğruluk açısından dikkate değer bir üstünlüğe sahip olmadığı sonucuna ulaşılmıştır.Global Navigation Satellite System (GNSS) provides to users fast, cost-effective and reliable geolocation service. It has become a practical tool for real-time positioning in many engineering applications with its real-time kinematics (RTK) method. The accuracy of the RTK method depends on the base distance between the reference station and the rover due to orbital error and atmospheric errors. Nowdays, RTK corrections can be transmitted over GSM with the development of internet protocols and the distance limitation caused by the radio modem has also disappeared. In general, RTK measurements are made by using GPS and GLONASS satellite systems. However presently, new GNSS systems such as GALILEO and BEIDOU are also available to users. In this study, a field test was carried out for testing the performance of the Internet based multi-GNSS classical RTK considering different base distances (~20, ~40, ~60, ~80 km) in Konya, Turkey. The RTK measurements at the each test point were performed using three same GNSS receivers-as rovers - which are placed on the same stand and configured to be track G, GR, GREC satellite combinations. RTK coordinates were obtained in three sessions at 10°, 20° and 30° elevation angles, approximately 9 hours at each application point with different satellite configurations. At each application point, about 5 hours of RTK measurements were taken in the first sessions (10°), as well as static data recording. The ground truth coordinates of the rovers were obtained by post-processing relative method using GAMIT/GLOBK software. The results were investigated in terms of accuracy and precision. The results showed that multi-GNSS combinations provided better repeatability at the 10° cut off angle option. The accuracy of GPS-only solutions varied between 0.63/2.17 cm and 2.40/4.94 cm for horizontal and vertical components, respectively. However, the multi-GNSS combinations did not have a remarkable superiority in terms of position accuracy even at 30° cut off angle compared to the GPS-only RT

Investigation of the effect of combined vitamin E-C and Se supplementation on heparin induced osteoporotic bone properties by biochemical and biomechanical techniques

Ph.D. - Doctoral Progra