Thesis. 1976. M.S.--Massachusetts Institute of Technology. Dept. of Civil Engineering. / Microfiche copy available in Archives and Engineering. / Bibliography: leaves 135-137. / by Jacques F. Risser. / M.S.

by Feng Gang. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (p. 169-181). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.

Problembakgrund: Sociala medier har blivit så viktigt att marknadsförare inte kan bortse ifråndem (Patino, Pitta och Quinones, 2012). Det är viktigt att företag har en klar strategi för hurmarknadsföringen på sociala medier ska se ut (Setreus, 2011). För att få djupare förståelse kringdet här bör användandet av sociala medier undersökas.Syfte: Uppsatsen syfte är att undersöka och beskriva konsumenters beteende på sociala medier,och upplevelser kring företags marknadsföring på sociala medier.Metod: Undersökningen har en kvalitativ ansats. Urvalet i studien är ett spontant uppsökandeurval av tolv individer, som har deltagit i totalt tre stycken gruppintervjuer med fyra personer ivardera.Slutsatser: Respondenterna i undersökningen använde i huvudsak sociala medier för att hållakontakten med vänner. De läste varandras profilsidor, och var noga med hur deras egnaprofilsidor såg ut. I huvudsak publicerade de mer bilder än text. Om företag skulle kontakta dempå sociala medier var det viktigt att respondenterna hade godkänt kontakten först.Praktisk betydelse: Uppsatsens har kommit fram till att för framgångsrik marknadsföring krävsdet en stark upplevd image från konsumenter. / Program: Kandidatutbildning i företagsekonomi

Det blir allt vanligare idag att de stora modehusen skapar barnkollektioner. Internationellt sätt har nästan varje stor designer redan gett sig in på barnklädesmarknaden. Jag valde dock att inte fokusera på den internationella marknaden utan undersöka hur den såg ut i Sverige med svenska modeföretag som hade olika positioner. Jag plockade ut ett antal märken som skiljde sig markant i målgrupp. Företagen jag har valt att ha med till studien är Acne, KappAhl och Polarn O. Pyret.KappAhl är ett stort modeföretag som riktar sig till herr, dam och barn. Företaget är inte mer nischade än att deras kläder ska hålla låga priser. KappAhl har en populär barnkollektion som de driver likt deras andra kollektioner starkt framåt. Polarn O. Pyret däremot har en helt annan bakgrund där de endast är fokuserade på barnmode. Det startade som ett barnklädesmärke och har inte kommit med några andra kollektioner än att de tillverkar en del mammatröjor i randigt som är deras signum för kläderna. Acne är intressant då företaget ligger i en helt annan prisklass och skiljer sig i målgrupp till skillnad från de föregående två företagen.Att jämföra de olika företagens inriktningar var intressant och lärorikt, att kunna analysera deras egna tankar och idéer kring en bransch om mode för barn. Det kändes som att rapporten inte riktigt fick sitt syfte förrän den psykologiska debatten sammanvävdes i studien. Hur man klär sina barn är en personlig smaksak och har troligtvis inga direkt negativa effekter i små åldrar. Däremot kan man ifrågasätta dagens medier inom barnmode då allt mer reklam riktas mot barn. Artiklar i modemagasin som lyder ”såhär ska barnen se ut i vår” låter egentligen mer som direktiv riktat mot föräldrarna. Allt fler framförallt unga tjejer har också tagit efter de stora modebloggerskorna och man kan se att i redan väldigt unga åldrar bloggar 12 åriga tjejer om hur man ska se ut i vår och vad som gäller. Kopplingen blir mellan hur modeföretagen själva ser på industrin och vad de själva anser att de har för ansvar gentemot de väldigt unga tjejerna.Debatten kring att barn ska få vara barn blir aktuell och detta försöker jag påvisa och genom att väva samman en rapport om vem som egentligen anser sig bära ansvaret. Föräldrar och modeindustrin absolut, men finns det då egentligen något rätt och fel om dessa unga tjejer brinner för mode. Det är meningen att studien skall göras så objektiv som möjligt, då slutsatsen av studien inte ska påvisa vad som är rätt eller fel utan diskutera de olika respondenternas svar kopplat till hur vi människor utvecklas under barnsåren. Analysen av modeföretagens arbetssätt, / Program: Textil produktutveckling och entreprenörskap

Ce document présente les travaux de thèse ayant pour objet la recherche et développement d’une technologie co-intégrée HEMT GaN normale-on/normally-off compatible avec les matériaux et procédés technologiques de la technologie normally-on hyperfréquence. Un exposé théorique et une revue de l’état de l’art permettent d’abord d’entrevoir les différentes solutions technologiques qui s’offrent à nous, tout en affirmant et en précisant les applications visées. Différentes briques technologiques sont ensuite développées pour la fabrication de MOS-HEMTs GaN à recess de grille sur des épi-structures à barrière AlGaN ou (Ga)InAlN dédiées aux applications hyperfréquences. Nous insistons sur la possibilité d’intégrer les 2 fonctionnalités normally-off et normally-on de manière monolithique. Les échantillons ainsi réalisés sont ensuite caractérisés électriquement de manière conventionnelle, mais aussi en utilisant des techniques avancées de spectroscopie de pièges comme les paramètres S à basse fréquence et la mesure du transitoire de RON. Bien que certains phénomènes de piègeage dans l’oxyde de grille soient mis en évidence, les résultats sont très satisfaisants : des composants normally-off sont obtenus pour les 2 structures, et les performances sont au niveau de l’état de l’art mondial, avec plusieurs pistes d’amélioration en perspective. / This document reports on research and development efforts towards a normally-on/normally-off integrated GaN HEMT technology that remains compatible with the material and processing dedicated to normally-on microwave devices. Following several theoretical considerations, the state-of-the-art is presented, which gives a perspective on the available technological solutions and helps define the specifications and the targeted applications. The development and optimization of new process steps enables the fabrication of gate-recessed MOS-HEMTs on epi-structures with AlGaN or (Ga)InAlN barrier, monolithically integrable with normally-on transistors. The samples are electrically characterized by means of standard measurements and more advanced trap spectroscopy techniques such as low-frequency S-parameters or RON transient monitoring. In spite of oxide-related trapping phenomena, the results are very promising: normally-off devices are obtained for both structures, and the performances are in line with literature accounts while identified possible improvements can be explored.

Active mode locking is one of the simplest ways to generate picosecond pulses at gigahertz repetition rates. In my works, I demonstrate the generation of picosecond pulses with a center-wavelength spanning from 1489nm to 1589nm using a polarization maintaining fiber loop mirror filter (PMF-LMF) in a mode-locked semiconductor optical amplifier (SOA) ring laser. By applying the SOA gain shifting technique and with the help of the controllable transmission ratio of the PMF-LMF, the tuning range of the output wavelength can be extended. By applying the technique of dispersion tuning, electrical wavelength tuning can be achieved across a range of 100nm. / Compared to the active mode-locking method, the regenerative mode-locking is very convenient because it does not require any external source for modulation and is proved to be more robust against fluctuations in ambient temperature. We demonstrate a 10-GHz regeneratively mode-locked fiber laser using a PMF-LMF. The operating frequency is determined by the free-spectral-range of the PMF-LMF and the component is extracted optically from the ring laser output. / In addition, we also demonstrate a simple technique to generate wavelength tunable picosecond pulses at adjustable repetition rate without using electrical or optical RF filter to extract the radio frequency (RF). The RF signal for mode locking is generated from a Fabry-Perot laser diode (FP-LD) under optical injection. The output frequency can be varied by adjusting the biasing current of the FP-LD. (Abstract shortened by UMI.) / Picosecond optical pulse sources with broad tunability and various repetition rates are key elements for applications in wavelength- and time-division multiplexed optical transmission systems. Mode-locking is one of the main techniques for the generation of optical pulses with high repetition rate picosecond pulse trains. This thesis presents our research efforts in high repetition rate optical pulse generation using active and regenerative mode-locking techniques, and a self-starting approach. We also demonstrate the application of harmonic mode locking in all-optical clock recovery from NRZ data. / Tang Wing Wa. / "August 2005." / Adviser: C. T. Shu. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 4015. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

by Guo, Xiao-Lei. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (p. 138-[147]). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.

by Kin-Yu Cheung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 64-[68]). / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Multistage Interconnection Architectures --- p.2 / Chapter 1.2 --- Interconnection Topologies --- p.4 / Chapter 1.3 --- Design of Switch Module-An Example of Multichannel Switch --- p.7 / Chapter 1.4 --- Organization --- p.8 / Chapter 1.5 --- Publication --- p.9 / Chapter 2 --- BMSN and SpiderNet: Two Large Scale ATM Switches --- p.13 / Chapter 2.1 --- Introduction --- p.13 / Chapter 2.2 --- Architecture --- p.14 / Chapter 2.2.1 --- Topology --- p.14 / Chapter 2.2.2 --- Switch Modules --- p.15 / Chapter 2.3 --- Routing --- p.17 / Chapter 2.3.1 --- VP/VC Routing --- p.18 / Chapter 2.3.2 --- VP/VC Routing Control --- p.22 / Chapter 2.3.3 --- Cell Routing --- p.23 / Chapter 2.3.4 --- Alternate Path Routing for Fault Tolerance --- p.24 / Chapter 2.4 --- SpiderNet --- p.25 / Chapter 2.5 --- Performance and Discussion --- p.26 / Chapter 2.5.1 --- BMSN vs SpiderNet --- p.26 / Chapter 2.5.2 --- Network Capacity --- p.29 / Chapter 2.6 --- Concluding Remarks --- p.30 / Chapter 3 --- Multichannel ATM Switching --- p.39 / Chapter 3.1 --- Introduction --- p.39 / Chapter 3.2 --- Switch Design --- p.40 / Chapter 3.3 --- Channel Allocation Algorithms --- p.41 / Chapter 3.3.1 --- VC-Based String Round Robin (VCB-SRR) Algorithm --- p.41 / Chapter 3.3.2 --- Implementation of the VCB-SRR Algorithm --- p.43 / Chapter 3.3.3 --- Channel Group Based Round Robin (CGB-RR) Algorithm --- p.50 / Chapter 3.3.4 --- Implementation of the CGB-RR Algorithm --- p.51 / Chapter 3.4 --- Performance and Discussion --- p.53 / Chapter 3.5 --- Concluding Remarks --- p.57 / Chapter 4 --- Conclusion --- p.62 / Bibliography --- p.64

This thesis is organized into three body chapters: (1) the first use of naturally rotating tearing modes to diagnose intrinsic error fields is presented with experimental results from the EXTRAP T2R reversed field pinch, (2) a large scale study of locked modes (LMs) with rotating precursors in the DIII-D tokamak is reported, and (3) an in depth study of LM induced thermal collapses on a few DIII-D discharges is presented. The amplitude of naturally rotating tearing modes (TMs) in EXTRAP T2R is modulated in the presence of a resonant field (given by the superposition of the resonant intrinsic error field, and, possibly, an applied, resonant magnetic perturbation (RMP)). By scanning the amplitude and phase of the RMP and observing the phase-dependent amplitude modulation of the resonant, naturally rotating TM, the corresponding resonant error field is diagnosed. A rotating TM can decelerate and lock in the laboratory frame, under the effect of an electromagnetic torque due to eddy currents induced in the wall. These locked modes often lead to a disruption, where energy and particles are lost from the equilibrium configuration on a timescale of a few to tens of milliseconds in the DIII-D tokamak. In fusion reactors, disruptions pose a problem for the longevity of the reactor. Thus, learning to predict and avoid them is important. A database was developed consisting of 2000 DIII-D discharges exhibiting TMs that lock. The database was used to study the evolution, the nonlinear effects on equilibria, and the disruptivity of locked and quasi-stationary modes with poloidal and toroidal mode numbers m=2 and n=1 at DIII-D. The analysis of 22,500 discharges shows that more than 18% of disruptions present signs of locked or quasi-stationary modes with rotating precursors. A parameter formulated by the plasma internal inductance l_i divided by the safety factor at 95% of the toroidal flux, q_95, is found to exhibit predictive capability over whether a locked mode will cause a disruption or not, and does so up to hundreds of milliseconds before the disruption. Within 20 ms of the disruption, the shortest distance between the island separatrix and the unperturbed last closed flux surface, referred to as d_edge, performs comparably to l_i/q_95 in its ability to discriminate disruptive locked modes, and it also correlates well with the duration of the locked mode. On average, and within errors, the n=1 perturbed field grows exponentially in the final 50 ms before a disruption, however, the island width cannot discern whether a LM will disrupt or not up to 20 ms before the disruption. A few discharges are selected to analyze the evolution of the electron temperature profile in the presence of multiple coexisting locked modes during partial and full thermal quenches. Partial thermal quenches are often an initial, distinct stage in the full thermal quench caused by radiation, conduction, or convection losses. Here we explore the fundamental mechanism that causes the partial quench. Near the onset of partial thermal quenches, locked islands are observed to align in a unique way, or island widths are observed to grow above a threshold. Energy analysis on one discharge suggests that about half of the energy is lost in the divertor region. In discharges with minimum values of the safety factor above 1.2, and with current profiles expected to be classically stable, locked modes are observed to self-stabilize by inducing a full thermal quench, possibly by double tearing modes that remove the pressure gradient across the island, thus removing the neoclassical drive.

In this thesis, novel multi-section laser diodes based on quantum-dot material are designed and investigated which exhibit a number of advantages such as low threshold current density; temperature-insensitivity and suppress carrier diffusion due to discrete nature of density of state of quantum-dots. The spectral versatility in the range of 1.1 µm – 1.3 µm wavelengths is demonstrated through novel mode-locking regimes such as dual-wavelength mode-locking, wavelength bistability and broad tunability. Moreover, broad pulse repetition rate tuning using an external cavity configuration is presented. A high peak power of 17.7 W was generated from the quantum-dot laser as a result of the tapered geometry of the gain section of the laser has led to successful application of such device for two-photon imaging. Dual-wavelength mode-locking is demonstrated via ground (?=1180 nm) and excited (?=1263 nm) spectral bands with optical pulses from both states simultaneously in the 5-layer quantum-dot two-section diode laser. The widest spectral separation of 83 nm between the modes was achieved in a dual-wavelength mode-locked non-vibronic laser. Power and wavelength bistability are achieved in a mode-locked multi-section laser which active region incorporates non-identical QD layers grown by molecular beam epitaxy. As a result the wavelength can be electronically controlled between 1245 nm and 1290 nm by applying different voltages to the saturable absorber. Mode-locked or continuous-wave regimes are observed for both wavelengths over a 260 mA – 330 mA current ranges with average power up to 28 mW and 31 mW, respectively. In mode-locked regime, a repetition rate of 10 GHz of optical pulses as short as 4 ps is observed. Noticeable hysteresis of average power for different bias conditions is also demonstrated. The wavelength and power bistability in QD lasers are potentially suitable for flip-flop memory application. In addition, a unique mode-locked regime at expense of the reverse bias with 50 nm wavelength tuning range from 1245 nm to 1290 nm is also presented. Broad repetition rate tunability is shown from quantum-dot external cavity mode-locked 1.27 µm laser. The repetition rate from record low of 191 MHz to 1 GHz from fundamental mode-locking was achieved. Harmonic mode-locking allows further to increase tuning up to 6.8 GHz (34th-order harmonic) from 200 MHz fundamental mode-locking. High peak power of 1.5 W can be generated directly from two-section 4 mm long laser with bent waveguide at angle of 7° at 1.14 GHz repetition rate without the use of any pulse compression and optical amplifier. Stable mode-locking with an average power up to 60 mW, corresponding to 25 pJ pulse energy is also obtained at a repetition frequency of 2.4 GHz. The minimum time-bandwidth product of 1.01 is obtained with the pulse duration of 8.4 ps. Novel tapered quantum-dot lasers with a gain-guided geometry operating in a passively mode-locked regime have been investigated, using structures that incorporated either 5 or 10 quantum dot layers. The peak power of 3.6 W is achieved with pulse duration of 3.2 ps. Furthermore, the record peak power of 17.7 W and transform limited pulses of 672 fs were achieved with optimized structure. The generation of picosecond pulses with high average power of up to 209 mW was demonstrated, corresponding to 14.2 pJ pulse energy. The improved optical parameters of the tapered laser enable to achieve nonlinear images of fluorescent beads. Thus it is for the first time that QD based compact monolithic device enables to image biological samples using two-photon microscopy imaging technique.