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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.
31

Optical Switch on a Chip: The Talbot Effect, Lüneburg Lenses & Metamaterials

Hamdam, Nikkhah January 2013 (has links)
The goal of the research reported in this thesis is to establish the feasibility of a novel optical architecture for an optical route & select circuit switch suitable for implementation as a photonic integrated circuit. The proposed architecture combines Optical Phased Array (OPA) switch elements implemented as multimode interference coupler based Generalised Mach-Zehnder Interferometers (GMZI) with a planar Lüneburg lens-based optical transpose interconnection network implemented using graded metamaterial waveguide slabs. The proposed switch is transparent to signal format and, in principle, can have zero excess insertion loss and scale to large port counts. These switches will enable the low-energy consumption high capacity communications network infrastructure needed to provide environmentally-friendly broadband access to all. The thesis first explains the importance of switch structures in optical communications networks and the difficulties of scaling to a large number of switch ports. The thesis then introduces the Talbot effect, i.e. the self-imaging of periodic field distributions in free space. It elaborates on a new approach to finding the phase relations between pairs of Talbot image planes at carefully selected positions. The free space Talbot effect is mapped to the waveguide Talbot effect which is fundamental to the operation of multimode interference couplers (MMI). Knowledge of the phase relation between the MMI ports is necessary to achieve correct operation of the GMZI OPA switch elements. An outline of the design procedures is given that can be applied to optimise the performance of MMI couplers and, as a consequence, the GMZI OPA switch elements. The Lüneburg Optical Transpose Interconnection System (LOTIS) is introduced as a potential solution to the problem of excessive insertion loss and cross-talk caused by the large number of crossovers in a switch fabric. Finally, the thesis explains how a Lüneburg lens may be implemented in a graded ‘metamaterial’, i.e. a composite material consisting of ‘atoms’ arranged on a regular lattice suspended in a host by nano-structuring of silicon waveguide slabs using a single etch-step. Furthermore, the propagation of light in graded almost-periodic structures is discussed. Detailed consideration is given to the calibration of the local homogenised effective index; in terms of the local parameters of the metamaterial microstructure in the plane and the corrections necessary to accommodate slab waveguide confinement in the normal to the plane. The concept and designs were verified by FDTD simulation. A 4×4 LOTIS structure showed correct routing of light with a low insertion loss of -0.25 dB and crosstalk of -24.12 dB. An -0.45 dB excess loss for 2D analysis and an -0.83 dB insertion excess loss for 3D analysis of two side by side metamaterial Lüneburg lenses with diameter of 15 μm was measured, which suggests that the metamaterial implementation produces minimal additional impairments to the switch.
32

Application Programming Interfaces : An exploration of their properties and what to consider during implementation

Mehmeti, Donika, Palmblad, Linus January 2022 (has links)
In this study, the focus is on facilitating the API discovery process for developers and organizations. According to research articles, APIs are discussed in this research as the fundamental areas that are considered significant when developers or organizations explore an API. The areas include usability, documentation, stability, collaborative communities, and the popularity of an API. We created a design and creation research process and listed key aspects of each mentioned area above in a final artifact, where the idea is to allow people to look at the artifact and use it in a possible API exploration. In conclusion, the artifact covers usability, documentation, stability, and collaborative communities. There are leading questions in the artifact to determine whether or not an API is suitable for a given purpose.
33

The sound of rage : the perceived impact of misophonia on daily life and relationships

Morales Gutiérrez, Silvia Estela January 2023 (has links)
Misophonia is a condition characterized by a strong physiological, emotional, and behaviouralresponse to specific auditory stimuli, which have a significant negative impact on the wellbeingof affected individuals. The present investigation focuses on emotional dysregulation, which arises due to the triggering of specific auditory stimuli. Individuals with misophoniastruggle to regulate their emotions when exposed to sounds, leading to emotional reactions, including anger, anxiety, disgust, avoidance behaviour, fight or flight, and feeling overwhelmed. These reactions might even lead to violent impulses directed towards the source of the sound. Despite its growing recognition, little is yet known about misophonia, and experts have not established any clear boundaries or criteria for the condition to be considered adisorder. As such, it is not yet included in any classification systems for disorders. The aim of this study is to understand how individuals with misophonia experience emotional dysregulation, how do they describe their experience, what is it like to live with misophonia ona day-to-day basis, and how do individuals understand and cope with emotional dysregulation caused by misophonia? The study utilized a qualitative approach with semi-structured interviews as the data collection method. Thematic analysis was used to identify patterns and themes within the data. Participants stated that misophonia causes significant distress and disruption impacting emotional well-being and daily functioning. Validation of this new condition can be very helpful and make a positive impact in their social circle, and that lack of awareness and effective treatment may hold back seeking professional help.
34

[en] GRADUATION METHODS UNDER PARAMETRIC AND NON-PARAMETRIC MODELS FOR SELECT AND ULTIMATE TABLES / [pt] METODOLOGIAS DE CONSTRUÇÃO DE TÁBUAS BIOMÉTRICAS SELETAS E FINAIS A PARTIR DE MODELOS PARAMÉTRICOS E NÃO-PARAMÉTRICOS

FABIO GARRIDO LEAL MARTINS 04 March 2008 (has links)
[pt] O estudo aborda as diversas metodologias de construção de tábuas biométricas: desde as técnicas de graduação tradicionalmente utilizadas para os casos em que há grande quantidade de dados, até um método específico de aplicação para o caso de poucos dados. Inclui uma discussão sobre as formas de construção de tábuas seletas, em particular de sobrevivência de inválidos. A população de servidores públicos estatutários da administração direta do município do Rio de Janeiro é utilizada para a graduação de tábuas de sobrevivência de válidos e de inválidos, enquanto que a dos aposentados urbanos por invalidez do INSS serve de base para a tábua seleta de sobrevivência de inválidos. / [en] This study represents an approach to the main methods of life tables construction. It shows traditional graduation techniques for cases including high exposure data, as well a methodology for few data. Further more, this study generates a discussion about select life tables construction, in particular disability mortality tables. Data set from Rio de Janeiro officials population were used for mortality and disability mortality tables construction. In addition, a select disability mortality table was constructed based on the INSS urban disability retired population.
35

Which agile methodology suits you? By applying the results on a multi-disciplinary project in a small company

Saadatmand, Fatemeh January 2013 (has links)
Choosing the Software Development Methodology is the very first step of any project; thus,has been a hot topic among, both, practitioners and academic people. After using plandrivensoftware development methodologies software development researchers came up withthe idea of agile software development methodologies as a masterpiece. Although, failurestories of some teams brought about fading the idea that agile methodologies are thebest recipe for any kind of development project. Considering the lack of studies in helpingpractitioners to select the most appropriate agile software methodology, this study aims atprovide the software development manager with a thorough knowledge of agile methodologiesand the criteria that should be considered, while selecting one of them. A case study is used asan empirical support. / Program: Magisterutbildning i informatik
36

Implementation of Pipelined Bit-parallel Adders

Wei, Lan January 2003 (has links)
<p>Bit-parallel addition can be performed using a number of adder structures with different area and latency. However, the power consumption of different adder structures is not well studied. Further, the effect of pipelining adders to increase the throughput is not well studied. In this thesis four different adders are described, implemented in VHDL and compared after synthesis. The results give a general idea of the time-delay-power tradeoffs between the adder structures. Pipelining is shown to be a good technique for increasing the circuit speed.</p>
37

Implementation of Pipelined Bit-parallel Adders

Wei, Lan January 2003 (has links)
Bit-parallel addition can be performed using a number of adder structures with different area and latency. However, the power consumption of different adder structures is not well studied. Further, the effect of pipelining adders to increase the throughput is not well studied. In this thesis four different adders are described, implemented in VHDL and compared after synthesis. The results give a general idea of the time-delay-power tradeoffs between the adder structures. Pipelining is shown to be a good technique for increasing the circuit speed.
38

Designing Surveys on Youth Immigration Reform: Lessons from the 2016 CCES Anomaly

Calkins, Saige 18 December 2020 (has links)
Even with clear advantages to using internet based survey research, there are still some uncertainties to which survey methods are most conducive to an online platform. Most survey method literature, whether focusing on online, telephone, or in-person formats, tend to observe little to no differences between using various survey modes and survey results. Despite this, there is little research focused on the interaction effect between survey formatting, in terms of design and framing, and public opinion on social issues, specifically child immigration policies - a recent topic of popular debate. This paper examines an anomalous result found within the 2016 Cooperative Congressional Election Study (CCES) public opinion immigration question focusing on a DACA-related policy, where support was evenly split on the typically highly favored policy. To decipher the unprecedented result, an experimental survey design was conducted via Qualtrics by comparing various survey formats (single-style, forced choice, Likert scale) and inclusionary policy details to the original CCES “select all that apply” matrix style. By comparing the experimental polls, the results indicated that the “select all that apply” matrix again produced anomalous results, while the various other methods produced a breakdown similar to typical DACA-related polling data. These findings have necessary implications for future survey designs and those examining public opinion on child immigration policies.
39

Investigating the Association between Adolescent Polysubstance Use, Crime, and Violence in the United States

Nwabueze, Christian 01 May 2021 (has links)
The lifetime prevalence of alcohol in the United States is 8% and lifetime prevalence of illicit drug use is about 2-3%. Substance use is common among adolescents and polysubstance use is becoming a public health threat. The prevalence of adolescent physical dating violence was 8.2%, the prevalence of adolescent sexual violence was also 8.2% while the prevalence of dual adolescent physical and sexual violence was 2.6%. Compared to those who used only single substances, adolescents who did not use any substance were 60% less likely (OR = 0.42, 95% CI = 0.24 – 0.74) to experience physical dating violence, 50% less likely (OR = 0.45, 95% CI = 0.31 – 0.66) to experience sexual dating violence and 70% less likely (OR = 0.34, 95% CI = 0.16– 0.69) to have experienced both physical and sexual dating violence. The prevalence of adolescent criminal arrests was 17.2%. Adolescents who combined select illicit drugs with alcohol were 1.7 times more likely to be arrested (OR = 1.66 ,95% CI = 1.49 – 1.85). Adolescents who used both select illicit drugs and marijuana were 1.5 times (OR = 1.55, 95% CI = 1.46 – 1.65) more likely to be arrested than those who used only select illicit drugs. Also, adolescents who used all three substances (select illicit drugs, alcohol and marijuana) were 1.6 times (OR = 1.62, 95% CI = 1.50 – 1.75) more likely to be arrested than those who used only select illicit drugs. The prevalence of weapon-related injuries was 7.4%. Adolescents who did not use substances were 50% less likely (OR = 0.47, 95% CI = 0.29 – 0.75, p The odds of dating violence, criminal arrests and weapon-related were higher with polysubstance use than with either mono-substance or no substance use. Therefore, prevention of substance use may be beneficial in reducing these public health concerns.
40

Σχεδίαση παράλληλης διάταξης επεξεργαστών σε ένα chip : δημιουργία και μελέτη high radix RNS αθροιστή

Γιαννοπούλου, Λεμονιά 09 July 2013 (has links)
Η άθροιση μεγάλων αριθμών είναι μια χρονοβόρα και ενεργοβόρα διαδικασία. Πολλές μέθοδοι έχουν αναπτυχθεί για να μειωθεί η καθυστέρηση υπολογισμού του αθροίσματος λόγω της μετάδοσης κρατουμένου. Τέτοιες είναι η πρόβλεψη κρατουμένου (carry look ahead) και η επιλογή κρατουμένου (carry select). Αυτές οι αρχιτεκτονικές δεν είναι επαρκώς επεκτάσιμες για μεγάλους αριθμούς (με πολλά bits) ή πολλούς αριθμούς, διότι παράγονται μεγάλα και ενεργοβόρα κυκλώματα. Στην παρούσα εργασία μελετάται η μέθοδος υπολοίπου (RNS), η οποία χρησιμοποιεί συστήματα αριθμών μεγαλύτερα από το δυαδικό. Ορίζεται μια βάση τριών αριθμών και οι αριθμοί αναπαρίστανται στα εκάστοτε τρία συστήματα της βάσης. Η άθροιση γίνεται παράλληλα σε κάθε σύστημα και τέλος οι αριθμοί μετατρέπονται πάλι στο δυαδικό. Τα πλεονεκτήματα αυτής της προσέγγισης είναι η παραλληλία και η απουσία μεγάλων κυκλωμάτων διάδοσης κρατουμένου. Το μειονέκτημα είναι ότι χρειάζονται κυκλώματα μετατροπής από και προς το δυαδικό σύστημα. Αυτού του είδους οι αθροιστές συγκρίνονται για κατανάλωση ενέργειας με τους γνωστούς carry look ahead και carry select. Διαπιστώθηκε ότι οι RNS αθροιστές καταναλώνουν λιγότερη ενέργεια. / The addition of many-bits numbers is a time and power consuming task. Many methods are developed to reduce the sum calculation delay due to carry propagation. Such techniques are Carry Look Ahead and Carry Select, Those techniques are not scalable to many bits numbers or a set of many numbers: the circuits needed are big and power consuming. In this thesis, the the RNS technique is investigated. This technique uses radix bigger than binary. A 3-numbers base is defined and the numbers that participate in the sum are represented uniquely in each element radix. The addition is performed in parallel in each radix. Finally the result is transformed back to the binary numbers system. The advantages of this technique are the parallelization of the process and the lack of carry propagation circuits. The disadvantage is that transformation circuits are need from/to binary system. The RNS adders are compared to CLA and CS for power. Such adders are compared to CLA and CS for power consumption. It is found that RNS adders consume less energy.

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