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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

VERIFICATION OF SHEAR LAG IN LONGITUDINALLY WELDED TENSION MEMBERS

Shrestha, Saurav 01 May 2017 (has links)
AN ABSTRACT OF THE THESIS OF Saurav Shrestha, for the Masters of Science degree in CIVIL ENGINEERING, presented on November 22, 2016, at Southern Illinois University Carbondale. TITLE: VERIFICATION OF SHEAR LAG IN LONGITUDINALLY WELDED TENSION MEMBERS. MAJOR PROFESSOR: Dr. J. Kent Hsiao, Ph.D., P.E. (CA), S.E. (UT) Tension members are used broadly as bracing members in buildings and truss. When double channels or double tees are welded to a gusset plate, stresses are distributed non-uniformly in connected members since only a part of its cross-section is connected. Shear lag factor describes this phenomenon. The main objective of this study is to verify shear lag factor of tension steel members with welded connections using the finite element computer analysis and the current design Specification for Structural Steel Buildings (AISC 2010). The provision for calculating shear lag factor, U, is given by AISC Specification as 1-x ̅/L for angles, tees, channels and wide flange tension members. Weld size and length of the weld are the main parameters studied here. The current AISC design provision over-estimates the design tensile strength of double channel shapes. While, for WT Shapes it under-estimates one. The increase in weld size and decrease in weld length shows slight change in shear lag factor. Comparison is also made with the equation proposed by Fortney and Thornton (2012). The equation under-estimates the design tensile strength of both sections.
2

An Experimental Study of the Influence of Eccentricity on Shear Lag Effects in Welded Connections

Orloff, Kenneth L. 16 June 2017 (has links)
No description available.
3

FLASH LAG EFFECT MODEL DISCRIMINATION

Gabbard, Stephen R. 23 August 2013 (has links)
No description available.
4

研發投入與產出對於企業經營績效之遞延效果-以我國電子業上市上櫃公司為例

吳佳瑋, Wu, Jia-Wei Unknown Date (has links)
對於從事創新績效相關研究的學者來說,在進行實證分析時,皆必須考量研發活動對於經營績效的影響並不僅止於當期,且存在著遞延效果;相同地,對於實務界的投資者來說,也必須考量各企業所進行的研發活動對其經營績效的遞延效果。過去學者將研發活動依流程分為投入與產出兩個構面,其中,研發產出又可再細分為數量與品質二部分,因此,本研究將就我國電子業上市上櫃公司,分別探討研發投入、產出數量與品質對於企業經營績效的遞延效果。 研究結果發現,研發投入之效益於未來第三年實現。研發產出數量對於經營績效並未呈現顯著的相關;而研發產出品質對於當年的企業經營績效即產生效益,且此效益及於未來二年。本研究推論,研發產出的數量雖能反映企業研發投入的成果,但唯有能夠高品質的產出,才能有效提升企業的經營績效。 / For scholars engaged in innovation performance research, they must consider that the impact of R&D activities on financial performance often has a time-lag effect; so do the investors in the capital market. In the past, researchers divided R&D activities into two aspects by means of the procedure, including R&D input and R&D output. The latter also includes the quantity and the quality of R&D output. Therefore, this thesis uses Taiwan’s electronics industry as a research sample and examines the lag-effect of R&D input, R&D output quantity and quality on the companies’ financial performance. The research results show that the benefits of R&D input are realized in the 3rd year in the future. In addition, the benefits of R&D output quality are realized in the current year, and last to the 2nd year in the future. However, there is no evidence for the relationship between R&D output quantity and companies’ financial performance. Overall, only can the high quality R&D output contribute to the companies’ financial performance.
5

Temporal patterns of memory source incorporations into dreams and their relationships to dreamed locus of control

Solomonova, Elizaveta 12 1900 (has links)
Les incorporations des mémoires épisodiques dans les rêves apparaissent en formes fragmentées et suivent un modèle temporel distinct qui suit une courbe sinusoïdale. Ce modèle est caractérisé par les incorporations immédiates, qui apparaissent 1-2 jours après l’événement (effet de résidus diurnes), et les incorporations tardives, qui apparaissent 5-7 jours après l’événement (effet de délai). Ces deux effets sont considérés comme des liens entre les processus de consolidation de la mémoire et la formation du rêve. Cette courbe temporelle a été observée pour une variété de stimuli expérimentaux. Cependant, aucune étude à date n’a démontré que le contenu des rêves réagit aux événements diurnes d’une manière plus générale et non-spécifique. Le but de notre étude était d’examiner si deux événements qualitativement distincts, un séjour nocturne au laboratoire (LAB), considéré comme un événement interpersonnel, et une tâche de réalité virtuelle (RV), considérée comme un événement non-interpersonnel, sont intégrés de façon différente dans le contenu onirique. Selon nos hypothèses, 1) les éléments spécifiques liés au LAB et à RV seraient incorporés dans les rêves avec des patrons tendances temporels différents, et 2) les incorporations spécifiques seraient associées à des changements plus généraux dans le locus de contrôle (LoC) du rêve. Vingt-six participants ont passé une nuit dans le laboratoire, ont été exposé à une tâche de RV, et ont rempli un journal de rêve pendant 10 jours. Les rapports de rêve ont été cotés pour les éléments spécifiques portant sur LAB et sur RV, et pour l'évolution générale de LoC du rêve. Nos deux hypothèses ont été confirmées: 1) les incorporations de LAB et RV sont négativement corrélées et apparaissent dans le rêve selon des modèles temporels différents. Les incorporations du LAB ont suivi une courbe sinusoïdale en forme de U, avec un effet de résidu diurne et un effet de délai. Les incorporations de RV ont suivi un patron différent, et ont eu un maximum d’incorporations au jour 4. 2) les scores du LoC du rêve étaient plus externes pour le jour 1 (max incorporations du LAB) et plus internes pour le jour 4 (max incorporations de RV). Ces modèles d'incorporation distincts peuvent refléter des différences dans la façon dont les deux événements ont été traités par les processus de consolidation de la mémoire. Dans ce cas, une expérience interpersonnelle (LAB) était incorporée plus tôt dans le temps. Les résultats suggèrent que LoC du rêve reflète les processus de mémoire plus généraux, qui affectent le contenu du rêve entier, et qui sont partiellement indépendants des incorporations spécifiques. / Memories for a daytime event reappear in fragmented form in dream content following a distinct, U-shaped, temporal pattern: immediate incorporations appear on days 1-2 after the event (day-residue effect) and delayed incorporation appear on days 5-7 after the event (dream-lag effect). These two effects are thought to reflect memory consolidation processes linked with dreaming. The U-shaped pattern has been observed for a variety of experimental stimuli, however, no studies have investigated whether dream content also reacts to daytime events in a more general or non-specific way. The aim of this study was to examine whether two qualitatively distinct events, an overnight laboratory (LAB) stay, considered as an interpersonal event, and virtual reality maze task (VR), considered as a non-interpersonal event, are incorporated differently into dream content. We expected that 1) specific elements related to the LAB and VR events would be expressed with different temporal patterns, and 2) these specific incorporations would be associated with more general changes in Dream locus of control (LoC). 26 participants spent one night in the laboratory, underwent a VR maze task, and kept a dream diary for 10 days. Dream reports were scored for specific LAB and VR elements and for general changes in Dream LoC. Two main findings confirmed our expectations: 1) LAB and VR incorporations were inversely related and exhibited distinct temporal patterns. LAB incorporations were U-shaped with both day-residue and dream-lag effects. VR vi incorporations followed a different pattern, with a peak on day 4. 2) Dream LoC scores were more external for day 1 (peak of LAB incorporations) and more internal for day 4 (peak of VR incorporations). These different incorporation patterns may reflect differences in how memory consolidation processes dealt with the two events, with the interpersonal experience being incorporated earlier in time. Dream LoC findings may reflect more general memory processes that are partially independent from the specific incorporations and that affect construction of the whole dream narrative.
6

Geometric Misalignment Calibration and Detector Lag Effect Artifact Correction in a Cone-Beam Flat Panel micro-CT System for Small Animal Imaging

Di Sopra, Lorenzo January 2015 (has links)
The cone-beam flat panel micro-CT is a high definition imaging system. It acquires projections of an object or animal to reconstruct a 3D image of its internal structure. The device is basically composed by a radiation tube and a detector panel, which are fixed to a gantry that rotates all around the test subject. The micro-CT system is affected by several imperfections and problems, that might lead to serious artifacts that deteriorate the quality of the reconstructed image. In particular, two issues have been discussed in the present work: the source-panel geometric misalignment and the detector lag effect. The first problem concerns the consequences of systems where the different elements are not perfectly aligned to each other. The second issue regards the residual signal, left in the detector's sensor after a projection acquisition, which affects the following frames with ghost images. Both these arguments have been investigated to describe their characteristics and behaviour in a typical acquisition protocol. Then two correction methods have been presented and tested on a real micro-CT device to verify their effectiveness in the artifacts compensation. In the end, a comparison between images before and after the corrections is provided and future prospects are discussed.
7

Temporal patterns of memory source incorporations into dreams and their relationships to dreamed locus of control

Solomonova, Elizaveta 12 1900 (has links)
Les incorporations des mémoires épisodiques dans les rêves apparaissent en formes fragmentées et suivent un modèle temporel distinct qui suit une courbe sinusoïdale. Ce modèle est caractérisé par les incorporations immédiates, qui apparaissent 1-2 jours après l’événement (effet de résidus diurnes), et les incorporations tardives, qui apparaissent 5-7 jours après l’événement (effet de délai). Ces deux effets sont considérés comme des liens entre les processus de consolidation de la mémoire et la formation du rêve. Cette courbe temporelle a été observée pour une variété de stimuli expérimentaux. Cependant, aucune étude à date n’a démontré que le contenu des rêves réagit aux événements diurnes d’une manière plus générale et non-spécifique. Le but de notre étude était d’examiner si deux événements qualitativement distincts, un séjour nocturne au laboratoire (LAB), considéré comme un événement interpersonnel, et une tâche de réalité virtuelle (RV), considérée comme un événement non-interpersonnel, sont intégrés de façon différente dans le contenu onirique. Selon nos hypothèses, 1) les éléments spécifiques liés au LAB et à RV seraient incorporés dans les rêves avec des patrons tendances temporels différents, et 2) les incorporations spécifiques seraient associées à des changements plus généraux dans le locus de contrôle (LoC) du rêve. Vingt-six participants ont passé une nuit dans le laboratoire, ont été exposé à une tâche de RV, et ont rempli un journal de rêve pendant 10 jours. Les rapports de rêve ont été cotés pour les éléments spécifiques portant sur LAB et sur RV, et pour l'évolution générale de LoC du rêve. Nos deux hypothèses ont été confirmées: 1) les incorporations de LAB et RV sont négativement corrélées et apparaissent dans le rêve selon des modèles temporels différents. Les incorporations du LAB ont suivi une courbe sinusoïdale en forme de U, avec un effet de résidu diurne et un effet de délai. Les incorporations de RV ont suivi un patron différent, et ont eu un maximum d’incorporations au jour 4. 2) les scores du LoC du rêve étaient plus externes pour le jour 1 (max incorporations du LAB) et plus internes pour le jour 4 (max incorporations de RV). Ces modèles d'incorporation distincts peuvent refléter des différences dans la façon dont les deux événements ont été traités par les processus de consolidation de la mémoire. Dans ce cas, une expérience interpersonnelle (LAB) était incorporée plus tôt dans le temps. Les résultats suggèrent que LoC du rêve reflète les processus de mémoire plus généraux, qui affectent le contenu du rêve entier, et qui sont partiellement indépendants des incorporations spécifiques. / Memories for a daytime event reappear in fragmented form in dream content following a distinct, U-shaped, temporal pattern: immediate incorporations appear on days 1-2 after the event (day-residue effect) and delayed incorporation appear on days 5-7 after the event (dream-lag effect). These two effects are thought to reflect memory consolidation processes linked with dreaming. The U-shaped pattern has been observed for a variety of experimental stimuli, however, no studies have investigated whether dream content also reacts to daytime events in a more general or non-specific way. The aim of this study was to examine whether two qualitatively distinct events, an overnight laboratory (LAB) stay, considered as an interpersonal event, and virtual reality maze task (VR), considered as a non-interpersonal event, are incorporated differently into dream content. We expected that 1) specific elements related to the LAB and VR events would be expressed with different temporal patterns, and 2) these specific incorporations would be associated with more general changes in Dream locus of control (LoC). 26 participants spent one night in the laboratory, underwent a VR maze task, and kept a dream diary for 10 days. Dream reports were scored for specific LAB and VR elements and for general changes in Dream LoC. Two main findings confirmed our expectations: 1) LAB and VR incorporations were inversely related and exhibited distinct temporal patterns. LAB incorporations were U-shaped with both day-residue and dream-lag effects. VR vi incorporations followed a different pattern, with a peak on day 4. 2) Dream LoC scores were more external for day 1 (peak of LAB incorporations) and more internal for day 4 (peak of VR incorporations). These different incorporation patterns may reflect differences in how memory consolidation processes dealt with the two events, with the interpersonal experience being incorporated earlier in time. Dream LoC findings may reflect more general memory processes that are partially independent from the specific incorporations and that affect construction of the whole dream narrative.
8

Využití počítačem zprostředkovaného procvičování učiva ve výuce biologie na gymnáziích / Employing Computer-Assisted Practise of Grammar School Biology Curriculum

Krump, Ondřej January 2018 (has links)
Growing knowledge in the field of cognitive science can significantly improve the way we learn. Several methods and principles are being repeatedly confirmed by numerous studies as effective for learning. They include spaced repetition, test-enhanced learning, and desirable difficulty principle. With the continual spreading of ICT technologies, diverse software is being developed as well, some of which more and some of which less successfully employs the methods and principles outlined. Memrise, Purpose Games and Drill and Skill, web platforms which are examined in this thesis, belong to this software family. In the first phase, i conducted several interviews with teachers who were using Drill and Skill as part of their science teaching at elementary schools and a junior grammar school (all of them were teaching children approx. 11-15 years old). After this, i worked with a class from a grammar school (age around 16). i made several groups of educational games to help the students practice the topics studied in their biology lessons. Each group of games was reviewed during a group interview. Recordings from these interviews as well as from the interviews with the teachers were transcribed and these transcripts underwent qualitative analysis, which is an important part of the thesis. Drawing on all...
9

InP-based photonic crystals : Processing, Material properties and Dispersion effects

Berrier, Audrey January 2008 (has links)
Photonic crystals (PhCs) are periodic dielectric structures that exhibit a photonic bandgap, i.e., a range of wavelength for which light propagation is forbidden. The special band structure related dispersion properties offer a realm of novel functionalities and interesting physical phenomena. PhCs have been manufactured using semiconductors and other material technologies. However, InP-based materials are the main choice for active devices at optical communication wavelengths. This thesis focuses on two-dimensional PhCs in the InP/GaInAsP/InP material system and addresses their fabrication technology and their physical properties covering both material issues and light propagation aspects. Ar/Cl2 chemically assisted ion beam etching was used to etch the photonic crystals. The etching characteristics including feature size dependent etching phenomena were experimentally determined and the underlying etching mechanisms are explained. For the etched PhC holes, aspect ratios around 20 were achieved, with a maximum etch depth of 5 microns for a hole diameter of 300 nm. Optical losses in photonic crystal devices were addressed both in terms of vertical confinement and hole shape and depth. The work also demonstrated that dry etching has a major impact on the properties of the photonic crystal material. The surface Fermi level at the etched hole sidewalls was found to be pinned at 0.12 eV below the conduction band minimum. This is shown to have important consequences on carrier transport. It is also found that, for an InGaAsP quantum well, the surface recombination velocity increases (non-linearly) by more than one order of magnitude as the etch duration is increased, providing evidence for accumulation of sidewall damage. A model based on sputtering theory is developed to qualitatively explain the development of damage. The physics of dispersive phenomena in PhC structures is investigated experimentally and theoretically. Negative refraction was experimentally demonstrated at optical wavelengths, and applied for light focusing. Fourier optics was used to experimentally explore the issue of coupling to Bloch modes inside the PhC slab and to experimentally determine the curvature of the band structure. Finally, dispersive phenomena were used in coupled-cavity waveguides to achieve a slow light regime with a group index of more than 180 and a group velocity dispersion up to 10^7 times that of a conventional fiber. / QC 20100712
10

廣告效果的實證研究

吳佳儒, Wu, Chia-Ju Unknown Date (has links)
隨著消費者、企業主對廣告意識的不斷提高和廣告知識的日益普及,廣告效果的研究問題是一項非常重要的課題。在以往的研究中,廣告效果可分為二種,一種是廣告的銷售效果,其方式是由銷售數字來衡量廣告效果;另一種是廣告的溝通效果,是以訊息接收者態度、行為的改變程度來衡量廣告效果。 本研究採用次級資料的分析方法,以實際產品的歷史資料做為分析的對象,並結合了廣告的銷售效果及廣告的溝通效果的理論,分別採用產品的銷售量及消費者對產品品牌的品牌態度二種指標來做為衡量廣告效果的依據,進一步地試圖比較同一產品內不同品牌間的廣告效果,以衡量廣告效果的成效。 除了廣告效果的衡量外,本研究也試圖研究台灣產業的廣告是否具有遞延效果。本研究將產品類別依產品特性、通路特性、產業集中度、廣告集中度及廣告密度進行分類,試圖研究這些分類方式的產品類別是否是影響到廣告效果,期望結果能提供廠商做一參考。 根據等級相關分析及順序迴歸分析的研究結果,本研究證實,廣告投入同時具有銷售效果與溝通效果,且大部分在廣告投入對銷售相關顯著的產品在對消費者品牌態度方面也會顯著,顯示廣告投入是同時影響銷售及消費者的品牌態度。在產品類別對廣告效果影響方面,將產品依不同產品特性、通路特性、產業集中度、廣告集中度及廣告密度進行分類檢定,所得出的結果皆為不顯著,代表沒有足夠的證據說明廣告效果會依不同產品特性、通路特性、產業集中度、廣告集中度及廣告密度等產品分類方式而有所差異。

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