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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.
41

Estimación de Costos Operacionales Producto de Eventos de Falla en una Red de Semáforos: Aplicación Caso La serena y Coquimbo

Pavez Andonaegui, Claudio Alejandro January 2007 (has links)
No description available.
42

0 per os : En analys av sjuksköterskors perspektiv på beslut att ge sondnäring till äldre individer med långt framskriden demenssjukdom / NPO : An analysis of the perspective of Registered nurses on decision regarding tube feeding in older individuals with advanced dementia

Nilsson, Sanne January 2017 (has links)
Sväljsvårigheter uppstår hos individer med avancerad form av demens som en del av sjukdomsprocessen. Det ställer krav på hälso- och sjukvården att bemöta dessa symtom när individen själv saknar den kognitiva förmågan att fullt hävda sin autonomi avseende nutritionsbehandling. Frågan om sondnäring via sond eller PEG är en adekvat behandling för dessa patienter aktualiseras. Även om det rent utav är ett övergrepp och omvårdnaden istället bör ta en palliativ riktning. Sjuksköterskan betraktar ofta sin kunskap inom området som egna personliga preferenser och inte något som kan hänvisas till i ett kliniskt vårdsammanhang. Syftet med denna studie var att utforska sjuksköterskans etiska medvetenhet kring administrering av sondnäring till individer med avancerad form av demens. Studien genomfördes utifrån en kvalitativ design med en empiriskt utformad intervju, en litteraturöversikt samt en etisk analys utifrån sjuksköterskans möjliga handlingsalternativ i beslutandeprocessen. Slutsatser av denna studie består till en del av att sjuksköterskan bör agera som advokat för individens upplevda bästa och önskemål, ej stödja läkares beslut om administrering av sondnäring till dessa patienter samt bidra till en värdig död inom den palliativa domänen för individen med minsta möjliga lidande som resultat. / Swallowing difficulties occur as a part of the disease process in individuals with advanced dementia. Demands is set on the healthcare-staff to meet with these symptoms when the individual due to loss in cognitive function, lack a complete ability to claim autonomy regarding nutritional treatment. The issue arises regarding enteral feeding by PEG or NG-tube as a viable treatment option for these patients. Even if it is an encroachment and that the care instead should be performed from a palliative point of view. Registered nurses view their knowledge within the area as personal preferences that they cannot refer to in a clinical setting. The aim of this study was to explore the nurse´s ethical awareness regarding enteral nutrition to individuals with advanced dementia. The study was conducted from a qualitative approach with an empirical interview, a literature review and an ethical analysis concerning the nurse’s possible actions’ in the decision making-process. Conclusions of this study consists to a part of that the nurse should act as the patient’s advocate regarding from what’s perceived to be the best for the patient and the patient’s wishes. Also, not supporting the doctor’s decision of tube feeding to these patients’ and to contribute to a dignified death within the palliative domain, with least possible suffering as a result.
43

An investigation of the molecular structure, composition and biophysical properties of gum Arabic

Gashua, Ibrahim Babale January 2016 (has links)
Acacia senegal and Acacia seyal are important agroforestry cash crops indigenous to several countries of sub-Saharan Africa, including Nigeria. The gum exudate produced by these species is termed gum Arabic which is an approved food additive (E414), primarily used as an emulsifier. In the current study, the molecular structure, composition and biophysical properties of gum samples harvested from mature trees of Acacia senegal at two specific ecolocations in Nigeria (NG1 and NG2), have been investigated together with two previously characterised gum samples harvested from A. senegal and A. seyal originating from Sudan. The monosaccharide sugar composition analyses have shown that the A. seyal gum had a lower rhamnose and glucuronic acid content than the A. senegal gum, but had higher arabinose content. No significant difference was observed between the sugar composition of the A. senegal gums from Sudan and Nigeria. The total protein content of the Nigerian gum samples were significantly higher than recorded for the Sudanese samples. The principal amino acids present in all the gum samples are hydroxyproline, serine, aspartame, threonine and proline which is in agreement with literature values. The hydrodynamic size of the molecules present in the gums was studied using dynamic light scattering and it was found that molecular association occurred in solution over time which was inhibited in the presence of an electrolyte. The comparison of droplet size distribution for emulsions prepared with A. senegal (NG1) and A. seyal gum samples showed that A. senegal sample was a better emulsifier than the A. seyal. Multilayer adsorption of the samples onto polystyrene latex particles was observed, which resulted in an increase in thickness of the adsorbed layer as a consequence of the interaction between the protein and carbohydrate within the molecules adsorbed on the emulsion surface. Preliminary analyses of the gums using transmission electron microscopy showed the presence of varied macromolecules, ranging in size from ~12 - ~60 nm. Immuno-gold negative staining (using JIM8 monoclonal antibody) indicated clear labelling of arabinogalactan-proteins present in the gums harvested from A. senegal, the labelling of the A. seyal sample was inconclusive. In summary, the data presented represents the first detailed comparison of the structure, composition and physicochemical characteristics of Nigerian Acacia gum exudates versus Sudanese samples (main global supplier) which have shown that gum obtained from Nigerian sources is a viable alternative to ensure future supply of this valuable natural resource.
44

Development of Zinc Oxide Piezoelectric Nanogenerators for Low Frequency Applications

Satti Nour, Eiman January 2016 (has links)
Energy harvesting using piezoelectric nanomaterials provides an opportunity for advancement towards self-powered systems. Self-powered systems are a new emerging technology, which allows the use of a system or a device that perform a function without the need for external power source like for example, a battery or any other type of source. This technology can for example use harvested energy from sources around us such as ambient mechanical vibrations, noise, and human movement, etc. and convert it to electric energy using the piezoelectric effect. For nanoscale devices, the size of traditional batteries is not suitable and will lead to loss of the concept of “nano”. This is due to the large size and the relatively large magnitude of the delivered power from traditional sources. The development of a nanogenerator (NG) to convert energy from the environment into electric energy would facilitate the development of some self-powered systems relying on nano- devices. The main objective of this thesis is to fabricate a piezoelectric Zinc Oxide (ZnO) NGs for low frequency (˂ 100 Hz) energy harvesting applications. For that, different types of NGs based on ZnO nanostructures have been carefully developed, and studied for testing under different kinds of low frequency mechanical deformations. Well aligned ZnO nanowires (NWs) possessing high piezoelectric coefficient were synthesized on flexible substrates using the low temperature hydrothermal route. These ZnO NWs were then used in different configurations to demonstrate different low frequency energy harvesting devices. Using piezoelectric ZnO NWs, we started with the fabrication of sandwiched NG for hand writing enabled energy harvesting device based on a thin silver layer coated paper substrate. Such device configurations can be used for the development of electronic programmable smart paper. Further, we developed this NG to work as a triggered sensor for wireless system using foot-step pressure. These studies demonstrate the feasibility of using ZnO NWs piezoelectric NG as a low-frequency self-powered sensor, with potential applications in wireless sensor networks. After that, we investigated and fabricated a sensor on PEDOT: PSS plastic substrate either by one side growth technique or by using double sided growth. For the first growth technique, the fabricated NG has been used as a sensor for acceleration system; while the fabricated NG by the second technique has worked as anisotropic directional sensor. This fabricated configurations showed stability for sensing and can be used in surveillance, security, and auto-mobil applications. In addition to that, we investigated the fabrication of a sandwiched NG on plastic substrates. Finally, we demonstrated that doping ZnO NWs with extrinsic element (such as Ag) will lead to the reduction of the piezoelectric effect due to the loss of crystal symmetry. A brief summary into future opportunities and challenges are also presented in the last chapter of this thesis.
45

Zabezpečení bezdrátových sítí IEEE 802.11 / Security of wireless computer networks IEEE 802.11

Škodák, Jaroslav January 2008 (has links)
This work describes available and used standards, protocols and mechanisms used to secure IEEE 802.11 wireless networks. In the next section are listed vulnerabilities and possible attacks against different types of security. The principles of individual attacks on authentication, WEP security and WPA/WPA2 personal mode are described and realized using various software especially linux program aircrack-ng. Password for WEP security is obtained by passive eavesdropping data, using ARP replay injection and by creating own frames. The last two methods are used to generate traffic on the network, which is captured and then used to derive the WEP password. By injecting ARP frames, password was found in the number 60 000 captured frames and about 180 000 frames of data was needed for passive method. Decryption of WEP frame was done by fragment and KoreK chopchop attacks. This decrypted frame could be used to create fake frames and obtain WEP password. Brute force attack is realized for security WPA (WPA2) personal mode (often due to lack of strong password) by comparing password (passphrase) from password list. Speed of comparing is about 200 passwords/s.
46

Zefektivnění zabezpečení bezdrátových sítí / Security Protection efficiency improvement for Wireless Networks

Marušek, Michal January 2009 (has links)
Nowadays every wireless radio-communication services encompass huge type of technology used for transfer video, voice or data. Wireless communication is the most expanded branch and many companies are using this technology because of low cost and simply management. The biggest advantage is easy connection to shared wireless medium and allows users of network to move around whole covered area. The most expanded types of wireless networks are called Wireless LAN (WLAN). With rising number of WLANs is rising chance to attack shared wireless medium by hacker and many sensitive information can be stolen or modified. To avoid this chance was created the first security protocol used in WLAN called WEP. Its goal was protect data transmitted trough WLAN as strong as were protected in wired networks. Unfortunately WEP was hiding a big weakness which can be used in a crack of WLAN in a minute with the aid of special software. Example of this kid of software can be Airsnort constructed to monitor shared medium and captured every packet transferred trough this medium. Based on statistical method Airsnort can obtain hidden password in a few minutes. The second type of this software can be Aircrack-ng, which can crack hidden password without any user connected to WLAN. Aircrack-ng uses active techniques to generate network load and can obtain password more effectively and faster. The result of both cases was successful and protection of WLAN was completely cracked. Later was created new security protocol called WPA, which had to fix the cryptography weakness of previous WEP. WPA was only temporary security protocol, during standard 802.11 was developing which had to offer highest security and integrity protection of transferred data trough WLAN. For this reasons was created new version of WPA called WPA2 which satisfy requirements of standard 802.11i. Both protocols WPA/WPA2 contain weakness, which can crash security of WLAN. This crack is based on authentication PSK. Attacker during authentication is using information from four-way handshake between user of WLAN and access point. Based on this information attacker can crack password with the aid of password list attack which took approximately 30 minutes. Based on previous result is important to chose strong password contains alphanumeric string or special strings with satisfy length.
47

Simulace Triple play služeb v pasivních optických sítích v prostředí OMNeT++ / Simulation of Triple Play services in passive optical networks with OMNeT++ application

Puchrík, Matej January 2015 (has links)
The thesis deals with dynamic bandwidth allocation in passive optical networks of NG- PON2 standard. The paper also describes the so-called. triple play services and the practical part is a simulation of these services in passive optical networks NG-PON2 in the simulation environment OMNeT ++. As part of this work modules for passive optical network NG-PON2 were created as an expansion of project INET. Namely ONU, OLT and splitter modules were created. The first four chapters are theoretical and descibe older standards PON networks, further NG-PON2 networks and DBA algorithm then describes triple play services and explains their current status respectively. In another part a description of the programm OMNeT++ a description of the structure of simulation models. The practical part contains a description of modules, implementation of DBA algorithm and its modification, design simulated topology and detailed description of the configuration simulation. At the end of the practical part presents the results of simulations with the corresponding explanations.
48

Využití optických zesilovačů v sítích NG-PON2 / Using Optical Amplifiers in NG-PON2 Networks

Hrmel, Martin January 2014 (has links)
The aim of the thesis was to introduce the standard ITU-T G.989. Introduction deals with passive network architecture, which clarifies the basic functional elements that occur in optical networks. Been described active components and the very principle of data transfer in the distribution network. Next section is devoted to new technologies that are defined for the latest generation of passive networks NG-PON2. There have been a principle of data transmission in such networks and their advantages and disadvantages. I described the principle of data transmission in such networks and their advantages and disadvantages. The practical part deals with creating a functional network of NG-PON2 also using optical amplifiers. Another suggestion was using a digital CATV transmission of QAM modulation under optical networks on a dedicated wavelength of 1550 nm. Also simulate the coexistence of this new standard with previous PON technologies. Finally, the work consisted in implementing the Miller’s code into OptSim v5.2 environment, which compared the transmission characteristics of each line of codes with this Miller’s code. All practical simulations were designed and simulated in program OptSim v5.2.
49

Výpočet zatížení vztlakových klapek letounu L410NG a porovnání s letovým měřením / Computational analysis of high lift devices loads for L410 aircraft and its comparison to experimental data

Florián, Martin January 2015 (has links)
The computational model design of a twin-engine, turbo-propeller, commuter aircraft and its two landing configuration analysis is the subject of the Master‘s thesis. The solution contents calibration part, creation of a computational mesh, global aerodynamics characteristics definition and detailed high lift devices load of L410 NG aircraft. The acquired results are compared to wind tunnel data. The comparison of accuracy and advantages of CFD is involved as well.
50

Návrh kompozitového směrového kormidla pro letoun L 410 NG / Design study of composite rudder of L 410 NG aircraft

Sokol, Filip January 2015 (has links)
This diploma thesis describes the design of composite structures rudder NG aircraft L410 based on the present Dural-weave construction. According to FAR 23 and circulars certification process is designed composite primary structure of the aircraft. It proposes the construction of a new rudder and selected materials design of a track composite materials. Program MSC Patran is this structure developed FEM model and using Nastran software Compost and the strength check.

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