• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 2266
  • 984
  • 491
  • 307
  • 254
  • 138
  • 77
  • 72
  • 61
  • 48
  • 35
  • 20
  • 20
  • 19
  • 17
  • Tagged with
  • 5829
  • 1241
  • 1070
  • 995
  • 906
  • 621
  • 579
  • 531
  • 529
  • 437
  • 386
  • 377
  • 370
  • 350
  • 320
  • 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.

DSFS: a data storage facilitating service for maximizing security, availability, performance, and customizability

Bilbray, Kyle 12 January 2015 (has links)
The objective of this thesis is to study methods for the flexible and secure storage of sensitive data in an unaltered cloud. While current cloud storage providers make guarantees on the availability and security of data once it enters their domain, clients are not given any options for customization. All availability and security measures, along with any resulting performance hits, are applied to all requests, regardless of the data's sensitivity or client's wishes. In addition, once a client's data enters the cloud, it becomes vulnerable to different types of attacks. Other cloud users may access or disrupt the availability of their peers' data, and cloud providers cannot protect from themselves in the event of a malicious administrator or government directive. Current solutions use combinations of known encoding schemes and encryption techniques to provide confidentiality from peers and sometimes the cloud service provider, but its an all-or-nothing model. A client either uses the security methods of their system, or does not, regardless of whether the client's data needs more or less protection and availability. Our approach, referred to as the Data Storage Facilitating Service (DSFS), involves providing a basic set of proven protection schemes with configurable parameters that encode input data into a number of fragments and intelligently scatters them across the target cloud. A client may choose the encoding scheme most appropriate for the sensitivity of their data. If none of the supported schemes are sufficient for the client's needs or the client has their own custom encoding, DSFS can accept already encoded fragments and perform secure placement. Evaluation of our prototype service demonstrates clear trade-offs in performance between the different levels of security encoding provides, allowing clients to choose how much the importance of their data is worth. This amount of flexibility is unique to DSFS and turns it into more of a secure storage facilitator that can help clients as much or as little as required. We also see a significant effect on overhead from the service's location relative to its cloud when we compare performances of our own setup with a commercial cloud service.

Development of electromechanical energy storage systems

簡瀚澎, Kan, Hon-pang. January 2003 (has links)
published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy

Development of electromechanical energy storage systems

Kan, Hon-pang. January 2003 (has links)
Thesis (M.Phil.)--University of Hong Kong, 2003. / Includes bibliographical references. Also available in print.

Accurate Hardware RAID Simulator

Weng, Darrin Kalung 01 June 2013 (has links)
Computer data storage is growing at an astonishing rate. With cloud computing and the growth of the Internet enterprise storage has been predicted to grow at rates as high as 300\% per year. To fulfill this need technologies such as Redundant Array of Independent Disks or RAID are being used in industry today. Not only does RAID increase I/O performance but also provides redundancy measures to protect against hardware failure. Even though RAID has existed for some time now and is well understood, proprietary optimizations such as command scheduling and cache strategies that are employed by current RAID controllers are not well known. This thesis presents a model for RAID 5 that incorporates these features and describes the overall function of hardware RAID controllers. Also a python implementation of this model, Accurate Hardware RAID Simulator (AHRS) is presented and validated against a current hardware RAID controller. It is shown that AHRS can reproduce the behavior of a hardware RAID system with an accuracy of 97.92\% on average compared to a LSI hardware RAID controller.

Vegetable storage, respiration and design criteria in a membrane storage system

Plasse, Robert. January 1986 (has links)
No description available.

Bathroom Hideouts : A search for new ways of storing / Badrummets gömställen : Jakten på nya förvaringsmöjligheter

Karlsson, Michael January 2011 (has links)
My examination project during spring 2011 has been carried out in collaboration with DuoBad, a bathroom furniture company situated in Alsterbro, Småland. Their focus is to develop, manufacture and market bathroom furnitures with genuine craftsmanship. Through their partnership with some of the most influential manufacturers of quality bathroom products they can create an entirely new room to enjoy.I initiated the collaboration with DuoBad for the examination project and have not started from a specific task, but together with the company I have been focused on adding new thinking regarding storage in bathroom furniture.The goal with the project has been to, together with DuoBad, develop a conceptual set of bathroom furniture that provides new ways of storing.The project was a close collaboration with users where experience gained through contextual interviews became the main source of inspiration.The result of the project is a bathroom furniture serie called Mill. The name comes from the manufacturing technique of milling, which is the identifying form language of the product.

Flywheel energy storage : a conceptucal study

Östergård, Rickard January 2011 (has links)
This master thesis was provided by ABB Cooperate Research in Västerås. This study has two major purposes: (1) to identify the characteristics of a flywheel energy storage system (FESS), (2) take the first steps in the development of a simulation model of a FESS. For the first part of this master thesis a literature reviews was conducted with focus on energy storage technologies in general and FESS in particular. The model was developed in the simulation environment PSCAD/EMTDC; with the main purpose to provide working model for future studies of the electrical dynamics of a flywheel energy storage system. The main conclusion of the literature review was that FESS is a promising energy storage solution; up to multiple megawatt scale. However, few large scale installations have so far been built and it is not a mature technology. Therefore further research and development is needed in multiple areas, including high strength composite materials, magnetic bearings and electrical machines. The model was implemented with the necessary control system and tested in a simulation case showing the operational characteristics.

The effect of physical and chemical agents on the storage characteristics of raw vegetables and fruits

App, Jean, Lorant, George John 25 July 1949 (has links)
This investigation was concerned with the reduction of waste in raw vegetables and fruits between the times of harvest and consumption. Reduction of spoilage in produce was attempted by means of chemical and. physical agents as well as a combination of both. The first phase of the work consisted of an evaluation of a number of chemical compounds with respect to their effectiveness in reducing post-harvest spoilage. The second part dealt with an evaluation of several transparent films applied to raw produce as wrappers and their effect on the keeping quality of the plant material until consumed. Finally combinations of surface disinfection and overwrapping were evaluated for effectiveness against raw produce spoilage. 1. Disinfection Approximately 26 compounds were tested as aqueous dips using 3 concentrations of each on 7 major vegetables and 2 fruits. The following types of compounds were studied. 1. Quaternary ammonium compounds (chlorides, bromides and pyridinium derivatives) 2. Chlorine liberators (organic and inorganic) 3. Phenols (simple and poly-phenols) 4. Quinones and hydroquinones 5. Salts of fatty acids 6. SO₂ liberators 7. Benzoates The chemical treatments were evaluated for each produce by comparison with untreated controls using duplicate tests with triplicate samples for each chemical and concentration. Promising treatments were found for all but one produce (strawberries). The treatments showing promise for each of Pascal celery and Emperor grapes were further tested on a larger scale uaing commercial size units of produce as test samples and long term cold storage. Three chemical treatments for each product were judged satisfactory enough to warrant further testing by means of field trials. The chemicals found most promising for celery were Onyxide, Cetab and Decco while Roccal, Dowicide C and Phygon were selected for grapes. A field test of the three above mentioned treatments for Pascal celery was completed. One thousand bunches per chemical were tested under commercial conditions of dipping and storing. An equal number of untreated bunches was also tested. Half-lots of each treatment were evaluated on each bunch for 11 subjective characteristics and standard mold and bacterial counts of each crate of celery were made after 8 and 14 weeks of storage. On the basis of a statistical analysis of the results, 0.1% Decco of pH=5 can be recommended for the reduction of general rot development in cold storage Pascal celery. Onyxide and Cetab significantly reduce the development of mold but commercial application cannot be recommended because the amount of visible stalk injury was significantly increased over that shown by corresponding untreated or Decco treated celery. 2. Prepackaging The following films were compared for their merit in prolonging the salable life of raw produce. Pliofilm 75FF, Pliofilm 75N2, Pliofilm 75P6A, Cellophane 300LSAT, Cellophane 300MSAT-86, Lumarith P-912, Dupont Acetate 100CA48, Polythene and Kodapak II-130. Wrapping techniques were also evaluated using the followng variations; Complete seals, tent-flap closures, single hole punctures, multiple punctures and windo bags. The following products were studied: celery, tomatoes, carrots, lettuce, cauliflower, chopped salad mix, spinach, strawberries, raspberries, blackberries, and boysenberries. Harvested produce was packaged both before and after the removal of field heat. Behavior of the pre-packaged products in both 33°F storage and subsequent 8O°F storage was studied. Cold storage was extended as long as 120 days while subsequent holding at room temperature varied widely from produce to produce. Observations were made at regular intervals for each product. Several hundred uniform samples were evaluated for most products using duplicates of each treatment for every observation period. Evaluation of most samples included weightloss, C0₂ (and sometimes O₂) of the container atmosphere, mold and decay development, flavor, color, odor, wilting and shriveling. The following conclusions were drawn: All films and wrapping methods affect produce quality. For each produce, treatments could be singled out which were superior to unwrapped controls. However any particular film and type of seal found to be superior for one produce was often not acceptable for another fruit or vegetable. Among the factors found to be critical for the proper choice of treatment were type of produce, produce temperature when packed, length of storage, and temperature of storage. A. Cold Storage For most products, the partially sealed, low permeability MSAT containers and the completely sealed Polythene wraps scored highst for overall product quality. These treatments prevented the accumulation of undesirable CO₂ while at the same time protecting the produce against weightloss and consequent wilting. For some produce, especially berries, wilting was not apparent even in high permeability films such as acetates. B. Warm Storage For produce with high respiration rates (spinach, and berries) only acetate films were acceptable as wraps. The partially sealed low permeability films maintained good quality in warm storage but the high humidity within the package was conducive to micro-organism activity. Thus, in many cases samples disinfected prior to packaging in those films improved the warm storage quality. Disinfection also improved the quality of tomatoes and chopped salad mix in acetate wraps. Of the high permeability films, no significant difference was found among the Dupont acetate, Lumarith and Kodapak II. The type of seal also did not affect the characteristics of these wraps. The low permeability films differed principally in the amount of CO₂, retained by the container during storage. The Pliofilms retained the highest C0₂, levels followed by LSAT and then MSAT Cellophane. The sealed polyethylene, the single puncture and tent flap MSAT wraps exhibited similarity, especially with respect to C0₂ accumulation. The multiple puncture low permeability wraps showed characteristics between acetates and the last mentioned group. Correlation between CO₂ accumulation and off-flavor formation could be determined for most products. Higher CO₂ levels were tolerated at short storage intervals without off- flavor formation by most products but the rate of change in CO₂ tolerance varied from produce to produce. Correlation between % weightioss and degree of wilting could also be expressed as a function of the pre-packaging treatments used. Storage infection was eliminated by all films independent of the type of seal used. It should be emphasized that only a study of the resuits and relationships discussed under each product can serve as a basis for future work and commercial application of the methods presented in this work. / Graduation date: 1950

Physical and chemical changes in stabilized mince from Pacific whiting during frozen storage

Magnusdottir, Edda 28 April 1995 (has links)
Cryoprotection in stabilized mince from Pacific whiting (Merluccius productus) was investigated by monitoring changes in physical and chemical properties during 32 weeks of frozen storage. The effects of 4 different cryoprotectants were evaluated by torsion test, color analysis, extractability of salt soluble proteins, and formation of dimethylamine (DMA) and 2-thiobarbituric acid (TBA). The quality of the stabilized mince was significantly higher than the control (mince without cryoprotectants) when compared by shear strain, salt soluble proteins, and DMA. The results show that the functionality of the proteins in the mince can be protected by using cryoprotectants with Polydextrose® being the most effective of the 4 tested. The effect of food-grade protease inhibitors on the gel-forming characteristics of Pacific whiting mince was also investigated. Four levels (1, 2, 3, and 4%) of different protease inhibitors (beef plasma protein, whey protein concentrate, egg white liquid, and egg white powder) were added to the stabilized mince before heating and effects on texture and color were evaluated. Shear strain was significantly increased by increasing the level of inhibitors. Beef plasma protein was most effective and presented significantly higher strain than the other inhibitors tested. Due to higher concentration of proteolytic enzymes in the mince, an increased amount of protease inhibitors is needed compared to surimi to prevent proteolysis during heating. / Graduation date: 1995

The tree as a stratagem for automatic information handling

Landauer, Walter I., January 1962 (has links)
Thesis (Ph. D.)--University of Pennsylvania, 1962. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves x-xi).

Page generated in 0.0886 seconds