• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 67
  • 19
  • 11
  • 6
  • 5
  • 4
  • 4
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 147
  • 37
  • 36
  • 32
  • 29
  • 25
  • 24
  • 21
  • 16
  • 15
  • 13
  • 12
  • 11
  • 11
  • 10
  • 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

Modelagem de processos para a gestão inteligente das informações no controle centralizado do tráfego

Freitas, Julia Lopes de Oliveira January 2014 (has links)
O controle centralizado do tráfego tem como objetivo integrar e gerenciar informações, auxiliando na tomada de decisão em tempo real. Devido ao aumento da complexidade da malha viária, principalmente em grandes cidades, muitos estudos têm focado em sistemas de controle de tráfego, incluindo desenvolvimento de novas tecnologias e ferramentas. Para gerenciar essa complexidade, é necessário que as organizações públicas, onde estão inseridos os Centros de Controle de Tráfego (CCT), conheçam e melhorem seus processos, alinhando e integrando-os aos seus sistemas de informação, de maneira a possibilitar o atendimento das demandas de forma eficiente. Nesse sentido, esta pesquisa baseia-se nos conceitos e práticas do Business Process Management (BPM) com objetivo de propor um modelo de estruturação dos processos para a gestão inteligente das informações no controle centralizado do tráfego. O trabalho, portanto, se desenvolve ao longo das fases e etapas do ciclo do BPM, contemplando desde o planejamento até a modelagem de processos e apresentando como resultado final uma proposta para um plano de otimização de processos. Assim, para atender ao objetivo principal da pesquisa, o trabalho foi desmembrado em três artigos com níveis crescentes de glanuralidade: (i) Inicialmente foi apresentada, baseada em estudo de caso, uma aplicação abrangente da metodologia, percorrendo da primeira à terceira fase do ciclo de BPM em que a empresa está apta para executar os processos e seguir para a quarta fase, Controle e Análise de Dados. (ii) O segundo artigo apresenta o detalhamento da segunda fase do ciclo de BPM, que consiste na modelagem e otimização dos processos. Os processos As Is foram, então, modelados e analisados para que pudesse ser proposta a melhoria na forma de um macroprocesso To Be. (iii) Para embasar a proposição do macroprocesso To Be, foi realizada uma revisão sistemática de literatura, na qual foram compiladas as melhores práticas no tema e verificadas para a realidade brasileira através de entrevista com especialistas. O resultado foi o Mapeamento de Melhores Práticas associado a um Modelo Referência para o Processo de Controle de Tráfego. Em complemento, foram determinadas diretrizes a serem seguidas para a gestão inteligente das informações no controle centralizado do tráfego. Esses resultados definem, portanto, um modelo de referência To Be dos processos de trabalho em CCTs. A principal contribuição teórica desta pesquisa é, então, a consolidação de melhores práticas associadas a um Modelo de Referência do Processo de Controle do Tráfego, ajustado para a realidade dos CCTs brasileiros. Do ponto de vista prático, a metodologia e os resultados apresentados incentivam a implantação de BPM não só em CCTs, mas em qualquer setor de uma organização pública. / The centralization of traffic control aims to integrate and manage information, aiding decision making in real time. Due to the increasing complexity of the road network, especially in large cities, many studies have focused on traffic control systems, including development of new technologies and tools. To manage this complexity, it is necessary that public organizations, where the Traffic Control Centers (TCC) are inserted, understand and improve their processes, aligning and integrating them into their information systems in order to enable the fulfillment of demands efficiently. In this sense, this research is based on the concepts and practices of Business Process Management (BPM) in order to propose a structuring model of processes for the intelligent management of information in centralized traffic control. The work, therefore, is developed through the phases and stages of the BPM cycle, covering from planning to process modeling and presenting as the final result a proposal for a process optimization plan. Thus, to meet the main goal of the research, the work was divided into three articles with increasing levels of detail: (i) initially it was presented, based on case study, a comprehensive application of the methodology, that cover from the first to the third phase of the BPM cycle in which the company is able to run the process and move on to the fourth phase, Control and Data Analysis. (ii) The second article presents the details of the application of second phase of the BPM cycle, which consists of modeling and optimization of processes. The processes "As Is" were modeled and analyzed in order to propose improvements trough a Macro process "To Be". (iii) To support the proposition of macroprocess “To Be”, a systematic review of the literature was applied in order to compile best practices on the subject that were checked for the Brazilian reality through interviews with experts. The result was a Map of Best Practices in association with a Reference Model for Traffic Control Process. In addition to the map, the paper presents guidelines to be followed for the intelligent management of information in centralized traffic control. These results define a reference model "To Be" of work processes in TCCs. From a practical standpoint, the methodology and results presented encourage the deployment of BPM not only in TCCs, but also in any department of a public organization.
42

Estudo de topologias para redes WDM-PON / Study of network topologies for WDM-PON

Guilherme Enéas Vaz Silva 19 March 2010 (has links)
A demanda de largura de banda exigida pelos usuários de redes de acesso vem aumentando rapidamente e a rede óptica passiva baseada em multiplexação por divisão de comprimento de onda (WDM-PON) tem se destacado como a tecnologia capaz de suprir essa demanda. Dessa forma, este trabalho conduz, inicialmente, uma comparação entre uma rede WDM-PON ideal e uma rede TDM-PON, discutindo também aspectos de segurança desta última, bem como estratégias de migração entre estes dois esquemas. Devido ao custo elevado da WDM-PON em seu esquema original, investigou-se em seguida as principais arquiteturas alternativas relatadas na literatura, em busca de maior viabilidade de implementação. Com base nesse estudo, fez-se então uma análise mais profunda sobre topologias recentes derivadas da RITENET, referenciadas na literatura como arquiteturas baseadas em fontes ópticas centralizadas (CLS). Tais configurações são baseadas no travamento de diodos lasers Fabry-Pérot através da injeção do sinal de ASE de um EDFA e foram estudadas por meio de simulações computacionais empregando o software OptiSystem 8.0. / The demand for bandwidth by access networks users has increased rapidly and the Wavelength Division Multiplexing - Passive Optical Network (WDM-PON) has been pointed out as the technology capable of meeting this demand. In this framework, this work initially carries out a comparison between an ideal WDM-PON network and a TDM-PON network, also discussing TDM-PON security issues as well as migration strategies from TDM-PON to WDM-PON configurations. Next, taking into account the high implementation cost of the WDM-PON original scheme, we investigated alternative topologies available in the literature. Based on this study, we performed a more in-depth analysis regarding recently proposed topologies, derived from the RITENET, which are refered at the literature as centralized light sources (CLS) based architectures. Such networks are based on the locking of Fabry-Pérot lasers diodes through the injection of the ASE signal from an EDFA and were studied by using the software OptiSystem 8.0.
43

Experimental Studies of Simultaneous Nitrification Denitrification and Phosphorus Removal at Falkenburg Advanced Wastewater Treatment Plant

Sager, Ann Elizabeth 23 March 2016 (has links)
The discharge of point- and non-point source pollutants into surface waters resulting from industrial and/or municipal activities is a major focus of environmental regulation in the United States. As a result, the National Pollutant Discharge Elimination System (NPDES) permit program was established in 1972 in an effort to regulate discharges from industrial or municipal sources, including wastewater treatment plants (WWTP). To further protect Florida water quality, in 1978, State legislation enacted the Grizzle-Figg Act for Tampa Bay, which requires advanced wastewater treatment for any discharge into sensitive water bodies. A common use of wastewater effluent in the Tampa Bay area is for reclaimed water for irrigation. This leads to an estimated 90% reduction of total nitrogen (TN) load to the bay in comparison to direct discharge (TBEP, 2016). One type of wastewater treatment process that has been shown to have low aeration and chemical requirements is simultaneous nitrification denitrification (SND), which can be carried out in an oxidation ditch. SND is a biological process for nitrogen removal where nitrification and denitrification occur at the same time within the same reactor. An oxidation ditch is a race-track type reactor that promotes the occurrence biological conversion of reactive nitrogen to nitrogen gas (N2) and additionally can provide enhanced biological phosphorus removal (EBPR). Many theories exist as to the mechanisms that allow SND to occur, but the literature is inconclusive as to whether the presence of different zones within the floc, within the reactor itself, a combination of the two or unique microorganisms are responsible for SND. Advantages of SND include efficient (80-96%) nitrogen removal, with significant reductions in energy, chemical, equipment and spatial requirements. Specifically, oxygen requirements are reduced and dedicated aerobic/anoxic zones, internal recirculation and supplemental carbon and alkalinity are not required. Despite these advantages, widespread use of SND is limited because of a lack of understanding of SND kinetics as well as interactions between factors affecting SND performance. This research was carried out at the Falkenburg Advanced Wastewater Treatment Plant (AWWTP) in Hillsborough County Florida, which carries out SND, biological and chemical phosphorous removal in an oxidation ditch system. Although this facility continually meets and exceeds its permit requirements, improvements in process control strategies have the potential to improve energy efficiency, as well as decrease chemical use, sludge production, greenhouse gasses (GHG) emissions and costs. Therefore, the overall goal of this research was to investigate mechanisms of nitrogen and phosphorus removal at the Falkenburg AWWTP. These goals were achieved through bench scale SND studies carried out at varying temperatures. Kinetic parameters were determined using a simple kinetic model of nitrification/denitrification. Additionally, carrying out sampling campaigns completed the investigation of the fate of phosphorus in the Falkenburg AWWTP. The results were combined with information on alum dosing and sludge wasting to determine the overall fate of phosphorus in the system and make additional recommendations regarding the addition of alum. To mimic an oxidation ditch at Falkenburg AWWTP, bench scale bioreactor experiments were set up in glass beakers at 22°C and 29.5 C. Influent wastewater and return activated sludge (RAS) for these experiments were collected from the Falkenburg AWWTP. Bioreactors were constantly mixed and aeration was controlled to maintain a target dissolved oxygen (DO) concentration based on measurements of DO at the facility. Three phosphorous sampling campaigns (October, November and December) were also carried out to understand the fate of phosphorous, nitrogen and organic carbon at the facility. In these campaigns, samples were taken at six locations at Falkenburg AWWTP and samples were analyzed for filtered and unfiltered total phosphorus, orthophosphate and polyphosphates, filtered and unfiltered total nitrogen, soluble, total and readily biodegradable COD (rbCOD), volatile acids, cations, anions, alkalinity, total suspended solids (TSS) and volatile suspended solids (VSS). pH and DO were also measured on site. In the nitrification batch reactors, in four hours, 50% of ammonia was successfully removed at a rate of 6.31 mg-N/L/hr indicating that four hours is not sufficient time to achieve complete removal. In the denitrification batch reactors, in six hours, there was successful removal of nitrate and nitrite at a rate of 23.70 mg-NO3-/L/hr and 3.6 mg-NO2-/L/hr. In an SND batch reactor experiments at 22° C, ammonia oxidation successfully occurred in 12 hours but denitrification was inhibited due to insufficient rbCOD in the reactor. In an SND batch reactor at 29.5° C, no accumulation of nitrate or nitrite was observed, indicating successful SND. At a higher temperature, sludge bulking occurred in the reactor resulting in variations in TSS and VSS concentrations. Results from the sampling campaigns at the treatment plant indicate that successful phosphorus removal was achieved. Alum addition varied before each sampling and a relationship between alum addition and sulfate can be made. rbCOD was consumed throughout the treatment process as expected and noticeable results can be noted when rbCOD was low in terms of phosphorus removal. The results of the bench-scale experiments showed that the SND was successfully achieved at the Falkenburg facility and that temperature, DO and rbCOD are all important factors controlling biological nutrient removal at SND facilities. DO is much more difficult to maintain and control at a higher temperature further supporting the idea that stricter operator control is needed in warmer months. Additionally, because SND removal still occurred with poor DO control at 29.5°C, it further supports the idea that SND occurs because of zones within the floc, the reactor or that novel microorganisms exist that allow denitrification to occur above ideal DO concentration and nitrification to occur below ideal concentrations of DO. A variation in rbCOD in the influent wastewater at the treatment plant caused nitrification and denitrification to be inhibited in different trials. With too much rbCOD, nitrification was inhibited and with too little rbCOD, denitrification was inhibited. Additionally, alkalinity consumption was minimal which supports the idea that supplemental alkalinity is not needed in SND processes. The results from the phosphorous sampling campaign show how important influent COD is for successful phosphorus removal in the system. The objectives were achieved and overall, the plant is achieving SND and EBPR and the plant is performing as designed. The addition of alum should continue to be studied to determine a better dose and save the county ratepayers money while still meeting permit regulations. Jar tests should be used to determine the proper dosing that will not hinder the settling properties further in the treatment train. Additionally, alum feed pipe sizes should be investigated at the plant to ensure no clogging occurs with a decrease in alum flow and automated aeration based on ammonia concentrations should be considered to remove the manual operation of aerators.
44

Centralized Purchasing Arrangements in a Selected Group of Oil Companies in the Southwest

Strong, Jerry C. January 1951 (has links)
The purpose of the study is threefold: (1) to make a survey of the type of purchasing organizations used by a selected number of oil companies operating in the Southwest, (2) to determine the extent or degree of centralized purchasing used by these firms, and (3) to evaluate briefly the organizational arrangements found in light of accepted principles.
45

Energy-Efficient Bandwidth Allocation for Integrating Fog with Optical Access Networks

Helmy, Ahmed 03 December 2019 (has links)
Access networks have been going through many reformations to make them adapt to arising traffic trends and become better suited for many new demanding applications. To that end, incorporating fog and edge computing has become a necessity for supporting many emerging applications as well as alleviating network congestions. At the same time, energy-efficiency has become a strong imperative for access networks to reduce both their operating costs and carbon footprint. In this dissertation, we address these two challenges in long-reach optical access networks. We first study the integration of fog and edge computing with optical access networks, which is believed to form a highly capable access network by combining the huge fiber capacity with closer-to-the-edge computing and storage resources. In our study, we examine the offloading performance under different cloudlet placements when the underlying bandwidth allocation is either centralized or decentralized. We combine between analytical modeling and simulation results in order to identify the different factors that affect the offloading performance within each paradigm. To address the energy efficiency requirement, we introduce novel enhancements and modifications to both allocation paradigms that aim to enhance their network performance while conserving energy. We consider this work to be one of the first to explore the integration of fog and edge computing with optical access networks from both bandwidth allocation and energy efficiency perspectives in order to identify which allocation paradigm would be able to meet the requirements of next-generation access networks.
46

Optimalizace způsobu přípravy teplé vody ve sportovních halách / Optimization of the ways of hot water preparation in sports halls

Dvořáková, Simona Unknown Date (has links)
The topic of this diploma thesis is to design the space and water heating system for a sport hall. The diploma thesis is divided into three chapters. The first chapter analyzes existing literature with a focus on heat transfer, pipe thermal insulation, hot water source, and existing normative and legislative requirements regarding hot water preparation. The second chapter consists of various calculations that regard the design of radiators, branch dimensioning, and design of water heating system for the target object. Additionally, this chapter contains an elaboration of a design documentation, which Detail Design Documentation. The third chapter focuses on an experimental water heating for the target object with a comparison of a centralized and decentralized water heating system.
47

Assessing the Impact of Centralizationon Safety Stock : A Scenario Based Case Study to Support Companies Exploring the Benefits of Utilizing a Centralized Warehouse Strategy in the Absence of Historical Data

Koundinya, Shashank, Ekendahl, Emil January 2023 (has links)
This master thesis investigates the comparison between centralized and decentralized warehousing systems, focusing on the variation in safety stock levels and the associated safety stock holding value. The aim of this research is to address the existing knowledge gap by introducing a methodology that utilizes scenario analysis in different potential locations, incorporating a range of plausible future circumstances and integrating them into a sophisticated mathematical model. This proposed approach seeks to estimate the potential inventory savings and corresponding cost reductions achievable through the implementation of a centralized warehouse. Additionally, it aims to examine the influence of different parameters on the anticipated impact of centralization, providing a comprehensive understanding of the potential outcomes. The findings of this case study will contribute to the academic discourse on warehouse optimization strategies as well as it will offer practical guidance to companies in their pursuit of operational excellence and cost savings within their supply chains. This thesis aims to bridge the gap between theoretical knowledge and practical implementation, facilitating informed decision-making processes by the supply chain practitioner and enhancing overall supply chain performance.
48

Aiding Strategic and Operational Decision Making in Hospital Centralized Scheduling Through Discrete-Event Simulation

Natale, James 07 June 2013 (has links)
No description available.
49

An Open Architecture for Versatile Machine and Actuator Control

Baxter, Michael Scott 03 September 2004 (has links) (PDF)
Automatic control technology increases usability, reliability and productivity in manufacturing, transportation, and climate control. There are many additional areas of modern life that could benefit through automatic control; however, current automation components are too expensive or aren't sufficiently flexible. For example, the cost of current commercial motion control components precludes their use in an average home. This thesis describes an automatic control methodology that is low cost and is flexible enough for a wide variety of control applications. Typical applications could include: - Home lighting, security and appliances - Commercial building heating, ventilation and air conditioning - Industrial machine tool and process control This automation methodology eliminates several expensive and inflexible aspects of present-day industrial automation. This is accomplished by implementing application-specific control algorithms in software run on a generic computer rather than on purpose-built hardware. This computer calculates control values for each control application connected to it via real-time communication network. This technique is similar to that of a desktop PC. When using a peripheral device, such as a printer or scanner, the PC executes device driver software to calculate control values for the devices. These values are communicated to the device over a shared bus. The automation methodology described here seeks to emulate this software-based control paradigm. This methodology reduces cost and increases flexibility in two ways. First, it eliminates application-specific control hardware and replaces it with software. This reduces the cost by eliminating the need for unique, proprietary control hardware for each product or system. Second, the software approach increases flexibility. For example, one could download a new clothes washing machine cycle via the Internet. Software control provides considerable freedom in designing and implementing control systems by allowing the designer to change system functionality without having to replace or modify hardware or even be present at the location where the control system is used. This thesis describes the development of this new control methodology. To validate its performance a home automation system is implemented. This implementation included control of laundry appliances, lighting, TV and other common household devices.
50

Responsibility center management: A financial paradigm and alternative to centralized budgeting

Bava, Dennis John 01 January 2001 (has links) (PDF)
Purpose . The purposes of this study were to (a) examine and describe the purpose and characteristics of responsibility center management (RCM) systems at two institutions of higher education, (b) describe the RCM system used at each institution at the school level of the organization, (c) examine and analyze the implementation of RCM at each institution, (d) identify the advantages and disadvantages of RCM systems at each institution, (e) examine and describe the impact of the RCM system on various constituencies affected by implementation of the process at each institution, and (f) provide data which may assist institutions of higher education in determining whether or not to institute a RCM model to assist administrators in the budgeting process. Procedure . The researcher conducted 12 interviews. Respondents included one provost, one chief financial officer (CFO) and one dean from each institution, and six faculty (three from each institution) who had knowledge of, in varying degrees, and/or responsibility for the school-level implementation of RCM systems. These individuals provided information regarding their perceptions of their respective RCM systems and related activities associated with the implementation process at each institution. Twelve content analyses were developed; two provost content analyses, two CFO content analyses, two dean content analyses, and six faculty content analyses. Two case studies were developed from the content analyses: one case study between the faculty and the administration at each institution. In addition, the researcher developed a cross-case summary from the case studies. Conclusions . The administrators in this study felt that RCM systems were implemented at each institution whereas; the faculty reported that this was not the case. Other significant findings included: (a) all the respondents indicated that each person or office might assume different roles depending on the stage of the RCM process however, good budget planning and performance was facilitated by stable environments; (b) ten out of the twelve respondents reported they could be responsible for their programs and accountable for fiscal integrity if they acted upon accurate and timely information; (c) four out of the six faculty pointed out that RCM implementation was more difficult at smaller institutions primarily, in increasing efficiency and reallocation of resources; (d) two administrators and six faculty raised concerns that information usually flowed downward in the authority hierarchy; (e) two administrators and six faculty indicated that tension resulted from the academic centers wanting more decentralization than the administration; (f) four out of the six faculty reported RCM implementation had occurred on paper only, without sufficient faculty input, and with insufficient information regarding the system's implications; and (g) all the respondents further indicated that they reserved judgment on the implementation of RCM systems until decentralization and autonomy for the academic centers is embedded in the institutional culture.

Page generated in 0.2528 seconds