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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.
191

Database server workload characterization in an e-commerce environment

Liu, Fujian 19 December 2005 (has links)
A typical E-commerce system that is deployed on the Internet has multiple layers that include Web users, Web servers, application servers, and a database server. As the system use and user request frequency increase, Web/application servers can be scaled up by replication. A load balancing proxy can be used to route user requests to individual machines that perform the same functionality. <br><br>To address the increasing workload while avoiding replicating the database server, various dynamic caching policies have been proposed to reduce the database workload in E-commerce systems. However, the nature of the changes seen by the database server as a result of dynamic caching remains unknown. A good understanding of this change is fundamental for tuning a database server to get better performance. <br><br> In this study, the TPC-W (a transactional Web E-commerce benchmark) workloads on a database server are characterized under two different dynamic caching mechanisms, which are generalized and implemented as query-result cache and table cache. The characterization focuses on response time, CPU computation, buffer pool references, disk I/O references, and workload classification. <br><br>This thesis combines a variety of analysis techniques: simulation, real time measurement and data mining. The experimental results in this thesis reveal some interesting effects that the dynamic caching has on the database server workload characteristics. The main observations include: (a) dynamic cache can considerably reduce the CPU usage of the database server and the number of database page references when it is heavily loaded; (b) dynamic cache can also reduce the database reference locality, but to a smaller degree than that reported in file servers. The data classification results in this thesis show that with dynamic cache, the database server sees TPC-W profiles more like on-line transaction processing workloads.
192

Schymans ben i Let’s Dance som kommunikationsstrategi : En fallstudie av Feministiskt initiativs kommunikation i valkampanjen 2010

Morell, Joanna January 2010 (has links)
Schyman’s legs in Let’s Dance as a communication strategy - a case study of “Feministiskt initiativ” in the election campaign 2010. (Schymans ben i Let’s Dance som kommunikationsstrategi, en fallstudie om Feministiskt initiativ i valkampanjen 2010). Author: Joanna Morell, Tutor: Ann-Marie Morhed 2009 was the first time where Swedish political parties were entitled to have TV- commercials, another sign of political communication taking one step closer to the strategic marketing communication. A type of communication that also is expensive. The Swedish political party Feministiskt initiativ (Fi) have existed since 2005 and is not yet a part of the Swedish parliament. They have not been entitled to the economic support that is given to Swedish parties with more than 2,5 percent of the votes in the last two elections. As a result Fi is completely dependent on economic contributions. Because of this it is crucial for them to get good value for the money they spend on communicating their brand. But how can then Fi, who have limited resources, make themselves heard? This question is what makes this study important. The purpose of this study was to investigate Fi and in which degree they made their brand visible to the public in the election campaign of 2010. I wanted to examine how efficiently they ran their election campaign, and by efficiently I mean to what degree the sender and receiver perception matched each other regarding the subjects: profile, communication and communication means. To examine if the sender and receivers perception matches each other; I’ve done a qualitative study, which includes a personal interview with the head of communication for Fi and four group interviews with people who voted for Fi, and people who didn’t. The result of these two will be reflected to theories that involve organizational identity and image, communication gaps and communication planning. The result of my study shows that Fi had small resources to communicate their profile through media. As a result Fi had limited access in media during the election campaign. The party used price efficiently strategies such as social media, network projects and the “brand Schyman” (living the brand). Because of the small resources communication gaps have evolved. Since Fi mainly use the strategy with the party as a network project there is a possibility that the wrong perception of their identity spread, which risks making existing communication gaps even bigger. This essay is 50 pages and is written in the autumn semester of 2010, for the course of Media and Communication Studies C. For the Division of Media and Communication, Department of Information Science, Uppsala University.
193

True Passion : En studie om varumärket Kosta Bodas profil och image

Gertsson, Mikaela, Svensson, Emma January 2010 (has links)
The purpose of this essay is to increase the understanding of how the management´s core values reflect the brand´s profile and image. To be able to fulfill that purpose, we used three problem statements that questioned how consumers, retailers and the employees of the company Kosta Boda perceived the brand. To accomplish this, we used a qualitative method. We started collecting theories about the topics: brand, image and profile that gave us a good foundation to build our qualitative interviews on and to increase the understanding for the topics. To collect imperical data, we interviewed consumers, retailers and employees at Kosta Boda both by email, phone and face-to-face interviews. After collecting the data, we could start analyzing these responses with the theory. After reading this essay, the reader will have gained insight into how the brand Kosta Boda is perceived by its environment and how well it matches the picture that the brand owner has of the company.
194

An Empirical Investigation of Eating Disorders and Difficulties Regulating Emotion: Do Difficulties Vary Based on Symptom Profiles?

Lacy, Jennie January 2011 (has links)
<p>Eating disorders pose a serious threat to the physical and mental health of those who suffer from them. Given the impact of these disorders and difficulty treating them, it is important to understand the nature of them and factors involved in their development and maintenance. The empirical investigation of eating disorders is made difficult by the extreme heterogeneity seen within current DSM-IV diagnostic categories. Research on emotion regulation in eating disorders is rising, yet scant in terms of identifying specific difficulties and points of intervention. The proposed study focused on the construct of emotion regulation and its relation to the eating disorders by: (1) empirically identifying groups of eating disorder participants based on symptoms and (2) examining specific difficulties in emotion regulation capacities in each of the identified groups of eating disorder participants and (3) identifying whether difficulties in emotion regulation contribute to eating disorder symptom severity. A clinical sample of individuals with eating disorders was classified into subgroups based on symptom frequency using latent profile analysis. The most parsimonious and best fitting model was a four-profile solution which resulted in four distinct subgroups. Profile 1 consisted of individuals who endorsed moderate restriction and occasional binge eating and vomiting, all at a subclinical level. Profiles 2, 3, and 4 all met criteria for bulimia nervosa and consisted of individuals who engaged in restriction, binge eating, and purging though in varying degrees. When these groups were compared to a sample of college aged healthy control participants using multivariate analysis of variance, results indicate that individuals in profile 1, which comprised 71% of the sample, experience greater difficulty with emotion regulation in the areas of awareness, nonacceptance, and perceived access to strategies to help them feel better. Results of three hierarchical regression analyses showed that difficulties in emotion regulation did not significantly contribute to symptom severity as anticipated..</p> / Dissertation
195

Beach profile variations under the action of irregular waves on submerged breakwaters

Hsu, Che-Chang 13 September 2012 (has links)
During the onslaught of a storm on the coasts of Taiwan in summer and autumn, large waves and storm surge have often caused beach erosion. In order to mitigate coastal disasters and erosion, soft-options have been promoted in recent years, to fulfill the purpose of shore protection, as well as to meet the new requirements of landscape, ecology and recreation. Consequently, semi-natural approaches have been adopted in stead of the conventional hard-structures. This thesis aims to report a study on the effects of detached submerged breakwater layouts and storm wave types on beach profile changes and berm retreat. In order to establish a practical procedure to assist the assessment of beach profile changes with submerged breakwaters during storm, we first collect and analyze the beach profile change data performed in large wave tanks (CE from the US and PI from Japan), and apply the well known SBEACH model to derive regression relationship between the two key parameters ( and ) in this model against the non-dimensional fall velocity ( ). The suggestion of Larson and Kraus (2000) to include hard bottom option in SBEACH with a set of modified and values, which may be different from that originally developed for a sandy beach environment, is then carried out using the beach profile changes results conducted experimentally with submerged breakwaters (Risio and Lisi, 2010). Consequently, we have conducted the numerical experiments systematically to study the beach profile changes using submerged breakwaters under various environmental combinations (with 10 different offshore distances, 10 breakwater heights, 10 crown widths and 4 types of storm wave conditions derived from storm return periods), from which a new set of and values are derived and used in SBEACH for the investigation of installing submerged breakwaters to mitigate potential beach erosion. Our numerical investigations using SBEACH for a beach with submerged breakwater reveal that: (1) Beach profile changes in erosion (0 m line and berm) and accretion (0 m line) due to regular waves are more significant than that of irregular waves. (2) Storm waves with a long return period cause more erosion to the shoreline (0 m line) and berm, while that with short return period may produce accretion to the shoreline. (3) The further a submerged breakwater away offshore, the more sediment transportation offshore and severe beach and berm erosion. (4).An increase of submerged breakwater height would result in accretion near the 0 line; except during a violent storm event, when an increase of berm height could reduce berm erosion. (5) An increase to the crown width of a submerged breakwater could only become effective to reduce wave energy and berm erosion, if an appropriate breakwater height is used; otherwise, a mere increase in width with insufficient height would increase wave height and berm erosion.
196

Data fusion of 3D profiles measured by projected fringe profilometry

Hsu, Yi-Ling 08 July 2005 (has links)
This paper presents a novel integration technique for segmented 3D profiles measured by projected fringe profilometry. Fringe patterns are projected to the inspected surface. The projected patterns fix their positions relative to the tested object during two segmented measurements. Thus, finding two matched surface points becomes a problem of searching for two identical phases in the fused data sets. This novel integration technique can match images successfully and achieve pixel-to-pixel registration easily even in the presence of geometric deformation, illumination changes, and severe occlusions. It is superior to the other methods because of its: (1) High matching accuracy; (2) Improved robustness; (3) Reduced computational time; (4) Capability of compensating distortions of the optical system at every pixel location; (5) Suitable for images rotating or scaling; and (6) Suitable for any other projected fringe measurement method. We also propose a method to design and fabricate a 2-D fringe pattern which can be applied to the integration technique for segmented 3D profiles. Campered with using 1-D fringe patterns for image registration, using a 2-D fringe pattern saves the measurement time and further proveds more tolerence to hand the shadow and noise problems. Tests of the system performance have been carried out that the accuracy of the registration scheme is 5.96% of image pixel size. Therefore, this technique can be extensively used in modern high technology industry. Especially when it requires higher resolution close-up images or overcomes the issue of not every inspected object can be fully expressed just by a single full-field measurement, it is necessary to use this integration technique.
197

Projected Fringe Profilometry using Diffractive Elements

Chen, Wei-jen 26 June 2006 (has links)
A technique using diffractive elements for finding the absolute shape of a large-scale object is proposed. An accurate projected fringe profilometry can be built by applying the holographic technique in this system. The advantages of using the presented technique for projected fringe profilemetry are : (1) a large depth of field ; (2) very low fringe distortion ; (3) a compact design for the measurement system ; (4) high accuracy ; (5) fast measurement speed.
198

PROJECTED FRINGE PROFILOMETRY USING A SUPERCONTINUUM LIGHT ILLUMINATION FOR MICRO-SCALE MEASUREMENT

Huang, chia-jeng 26 June 2006 (has links)
Abstract A projected fringe profilomertry ¡]PFP¡^ using a supercontinuum light illumination for micro-scale measurement is proposed. The supercontinuum light is generated by launching ultra short laser into a highly nonlinear photonic crystal fibers. The supercontinuum light with the following advantage¡G ¡]1¡^ Depth of the field is very large in the projected system. ¡]2¡^No speckle noise in the illumination system. Experiment results has shown that using supercontinuum light is superior to other illumination system This study indicates that the proposed measurement scheme could be applied to 3D shape measurements with large depth variation, especially for semi-conductor devices¡Bmicro electro-mechanical devices and biomedical species.
199

Planning for Curved-Surface Milling and Surface Profile Measurement by Taguchi Method

Wang, Hsueh-o 30 June 2006 (has links)
ABSTRACT This research uses Taguchi Method, combined with Computer Aided Design and Manufacturing, processing the work piece into the saddle type. Next, diverse sampling methods are applied to measure the profile of surface with Coordinate Measuring Machine, with an aim to analyzing the main factors that influence cutting and seeking the last conditions for cutting out the curved surface; in addition, I will probe into the contribution rate of each factor which influences the precision during the process of measurement. The following results of this research are expected to be offered to the circles of vocational education as a basis of processing and measuring instruction. In this way, it will not take too much time to try and error and therefore, the practice course can be more efficient. 1. With reference to the documents that are focused on the factors affecting the cutting, this thesis, by means of Taguchi Method, shows that during the process of cutting saddle-type curved surface, the rotating speed of the axle is the most influential, whose contribution rate is 59.38%. 2. Since most documents are on circles, balls or cone objects, this thesis will aim at the measurement of saddle-type curved surface, with an intention to further the measuring technique. 3. It is found that as to the saddle-type curved surface, random sampling can get the profile of surface with minimal errors, and has no such trouble as using HSS or LHS, which can reduce time and cost. 4. In the experiment of Taguchi Method, according to analysis of variance, the influence of the sampling area is the greatest while the choice of sampling method only contributes to 3.46%.
200

Projected Fringe Profilometry for dynamic micro-scale measurements

Huang, Jun-shan 19 July 2007 (has links)
A novel technique using projected fringe profilometry with pulsed illuminations for finding the absolute shape of a dynamic object, which is vibrating with high frequency, is proposed. The proposed method can accurately describe the observed 3D shape at a sequence of time. Even though the tested object vibrates up to 10K-Hz, the proposed method can accurately describe the observed 3D shape at any specific time. Depth accuracy better than one part in ten thousandths of the field of view can be achieved even with excessive image noises. Furthermore, the light source is temporally incoherent and spatially coherent, providing a speckle-free and a large depth-of-focus illumination. Thus, a highly accurate, non-scanning projected fringe profilometer with large depth measuring range for dynamic measurements can be realized.

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