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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.
11

Performance evaluation and design for variable threshold alarm systems through semi-Markov process

Aslansefat, K., Gogani, M.B., Kabir, Sohag, Shoorehdeli, M.A., Yari, M. 21 October 2019 (has links)
Yes / In large industrial systems, alarm management is one of the most important issues to improve the safety and efficiency of systems in practice. Operators of such systems often have to deal with a numerous number of simultaneous alarms. Different kinds of thresholding or filtration are applied to decrease alarm nuisance and improve performance indices, such as Averaged Alarm Delay (ADD), Missed Alarm and False Alarm Rates (MAR and FAR). Among threshold-based approaches, variable thresholding methods are well-known for reducing the alarm nuisance and improving the performance of the alarm system. However, the literature suffers from the lack of an appropriate method to assess performance parameters of Variable Threshold Alarm Systems (VTASs). This study introduces two types of variable thresholding and proposes a novel approach for performance assessment of VTASs using Priority-AND gate and semi-Markov process. Application of semi-Markov process allows the proposed approach to consider industrial measurements with non-Gaussian distributions. In addition, the paper provides a genetic algorithm based optimized design process for optimal parameter setting to improve performance indices. The effectiveness of the proposed approach is illustrated via three numerical examples and through a comparison with previous studies. / Noavaran Electronic Adar Sameh company [Grant NO: IRAM17S1].
12

An alarm system for pore pressure measurements in the foundation ofconcrete dams : a case study of Storfinnforsen buttress dam

Falcão de Queiroz, Daniel January 2018 (has links)
Concrete buttress dams are relatively light structures and less demandingon foundations; because of that, they may have problems with upliftforces and horizontal joints in the area of the dam´s foundation maypresent a failure mode through sliding. The Storfinnforsen dam, thelargest concrete dam in Sweden, had its foundation studied recently andthe discovery of sub-horizontal joints in the bedrock led to the necessityof having the safety of the dam foundation to sliding assessed.The safety is dependent on the pore pressure, which can vary throughtime. The implementation of an alarm system to monitor and assess thevalues of the pore pressure is necessary to improve the dam´s operation.In this thesis, a new system on how to define alarm limits for measuredpore pressures is suggested.The proposed alarm system will monitor the pore pressure of the joint,calculate the safety factor against sliding, compare it to the alarm limits ofthe system (adopted from RIDAS) and present countermeasures to theproblem.The analysis and implementation of the alarm system on monolith 42 ofStorfinnforsen showed that it does not comply with the Swedishguidelines with respect to sliding stability, but the measured porepressures are low enough to allow the creation of an alarm system thatwill monitor the pore pressure continuously. Furthermore, thecharacteristics of the local geology exclude any quick development of porepressure allowing countermeasures to be applied.However, further research on the definition of alarm limits for this kindof problem is needed. / Lamelldammar av betong är relativt lätta konstruktioner med mindrepåkänningar på grunden jämfört med konventionellagravitationsdammar. Till följd av detta är de också känsliga för upptryck.I kombination med förekomsten av sub-horisontella sprickplan iberggrunden kan detta utgöra en risk för glidning. Vid Storfinnforsensbetongdamm, vilken är Sveriges största lamelldamm, har undersökningarav berggrunden genomförts. I samband med dessa undersökningaridentifierades sub-horisontella sprickplan i berggrunden ochmonoliternas glidstabilitet har därför analyserats med avseende påglidning. Dränage har även borrats och portrycksmätare installerats föratt övervaka portrycket i berggrunden.Portrycket, och därmed dammens säkerhet mot glidning, kan emellertidvariera över tid. Det är därför nödvändigt att utveckla och implementeraett alarmsystem för att övervaka portrycket och säkerställa dammenssäkerhet. I följande examensarbete har ett nytt system utvecklats för attdefiniera alarmgränser för uppmätta portryck. I det föreslagnaalarmsystemet övervakas portrycket över sprickplanen, säkerhetsfaktornmot glidning beräknas och jämförs mot gränser baserade på acceptablasäkerhetsfaktorer från RIDAS. Om uppmätta portryck överstigeralarmgränserna implementeras fördefinierade åtgärder.I detta arbete implementerades alarmsystemet på monolit 42 iStorfinnforsens lamelldamm. Resultaten från en inledandestabilitetsanalys visade att säkerhetsfaktorn mot glidning inte uppfyllerställda krav enligt RIDAS riktlinjer. De uppmätta portrycken äremellertid tillräckligt låga för att möjliggöra användningen av ettalarmsystem som övervakar portrycken kontinuerligt och därmedsäkerställer att säkerheten mot glidning uppfylls. Om portrycken skulleöverstigas ges förslag på möjliga åtgärder som kan genomföras för attsänka portrycken. Vidare indikerar de lokala geologiska förhållandena attVsnabba höjningar av portrycken till följd av exempelvis urspolning avfyllnadsmaterial från sprickplan är osannolika, vilket möjliggörimplementering av de fördefinierade åtgärderna om portrycket skullestiga. Vidare forskning rekommenderas emellertid på hur snabbtportrycken kan stiga till följd av olika scenarier såsom nedbrytning avinjekteringsridåer.
13

Funktionsbeskrivning av brandlarmsstyrningen i ventilationssystemet ombord korvett av Göteborgsklass

Jonsson, Jesper January 2010 (has links)
Denna slutrapport beskriver projektarbetet Funktionsbeskrivning av Brandlarms-styrningen av Ventilationssystemet ombord Korvett av Göteborgsklass som beställdes av divisionsingenjören vid 41.korvettdivisionen. Bakgrunden till projektets beställning var att fartygens dokumentation över ventilationssystemets funktion vid brand var bristfällig vilket försvårade underhåll, felsökning och utbildning av och på systemet. Den ofullständiga dokumentationen var ett resultat av att individerna i fartygs­klassen modifierats i flera olika omgångar utan att dokumentationen uppdaterats på ett tillfredsställande sätt. Det hade även framkommit att det fanns olikheter i konfigurationen av fartygsindividernas system. Projektet genomfördes dels genom studier av den befintliga dokumentation som fanns att tillgå ombord och på divisionen, dels genom praktiska under­sökningar ombord på fartygen. Under de praktiska undersökningarna framkom behov av ytterligare utredningar än de som ursprungligen framgick av det erhållna uppdraget. Projektet påvisade skillnader mellan fartygens system, vissa förmodat felaktiga styr­ningar av fläktar och spjäll samt fastställde att dokumentationen var bristfällig. Projektet resulterade i ett antal beskrivande dokument som sammanställdes i en pärm för respektive fartyg. Dessa uppfyller det givna uppdraget och målen med projektet. En större modifiering av fartygen i klassen med syfte att förlänga deras operativa livslängd är under planeringsstadiet. Under modifieringen skall bland annat fartygens dokumen­tation uppdateras, något som resultaten från detta projekt kommer underlätta. / This is the final report regarding the project A Functional Description of the Fire Alarm Con­trol in the Ventilation System aboard the Swedish Navy’s Gothenburg-class Corvettes, wh­­ich was commissioned by the Senior Marine Engineer Officer of the 41st Corvette Sq­­ua­d­ron of the 4th Naval Warfare Flotilla. The reason for the commission was that the set of documentation concerning the function of the ventilation system in case of a fire was insufficient. This caused problems, both during maintenance work done to en­­­su­re that the system was operating in accordance with the design parameters, as well as when trouble-shooting the system. The insufficient set of documentation was a result of a number of upgrades done to the ships over the ye­ars without any corr­e­s­p­on­ding up­date of the documentation. During the project it has also been made clear that there were non-documented differences existing be­­tween the ships in the class. The project was fulfilled by a combination of studies of the existing set of do­cumen­tation and practical surveys aboard the ships. During the surveys, more short­comings in the existing set of documentation became evident. The project demonstrated differences between the individual ships, assumed inaccuracies in the control of fans and dampers and determined the shortage in the set of documentation. The project has resulted in a number of describing documents that are collected in one unique file for each ship. These documents fulfil the commission and the objectives of the project. A major upgrade of the ships in the class with the purpose of extending their operational lifetime is now being planned. The ships’ set of documentation will be simultaneously updated, a task that will be simplified with the support of the results of this project.
14

Análise de risco para embarcações com sistemas de alarmes com foco nos fatores humanos e organizacionais. / Risk analysis for ships with alarm systems, focusing on human and organizational factors.

Barbarini, Luiz Henrique Maiorino 11 May 2012 (has links)
Este trabalho apresenta uma proposta de modelo de análise de risco para embarcações, incorporando em sua formulação a influência das interações entre os sistemas de alarmes e os fatores humanos e organizacionais presentes a bordo. De acordo com estatísticas de sociedades classificadoras, o homem é o maior responsável por acidentes marítimos, e, desta forma, é um dos principais componentes da segurança de uma embarcação. A relevância do elemento humano se dá pelo fato de que ações e decisões humanas estão relacionadas tanto à causa, quanto à prevenção de acidentes. O sistema de alarmes é um equipamento de segurança obrigatório, e com direta participação na dinâmica de um acidente, fornecendo informação para a tomada de decisão das ações por parte da tripulação na resolução do problema. O estudo da interação entre este equipamento e o elemento humano a bordo permite a gestores e armadores elaborar diretrizes para investimentos em sistemas de segurança e políticas que influenciam o desempenho humano, e, portanto, a segurança a bordo. O modelo proposto, inspirado em relatório de acidentes marítimos, tem como ponto de partida uma estrutura sequencial do acidente e leva em consideração uma sucessão usual e simplificada dos eventos ocorridos, iniciando a partir de uma falha no sistema físico. O elemento humano, então, é incorporado à análise de risco através das técnicas de análise de confiabilidade humana, as quais têm como princípio a visão do homem como mais um componente do sistema, ou o liveware interagindo com software e hardware. Sob este ponto de vista, uma abordagem sócio-técnica é aplicada, ou seja, considera-se que um navio é composto não apenas de sua estrutura e máquinas, mas também de toda a tripulação. Com o objetivo de exemplificar passos e hipóteses de uma aplicação do modelo proposto, é apresentada a aplicação ao caso do acidente da embarcação Maersk Doha, ocorrido em outubro de 2006 nos Estados Unidos, cujo relatório de investigação do acidente é de acesso público via Internet, no site da Marine Accident Investigation Branch MAIB. / This work presents a risk analysis model for ships, focusing on the scenarios where the crew interacts with the alarm and monitoring system. According to statistics of classification societies, humans are largely responsible for accidents on board and, therefore, are considered a major component of the safety of vessels. The relevance of the human element is given by the fact that human decisions and actions are related to the cause of accidents, either being the direct causative factor of failure or influencing the probability of failure, and the prevention of accidents or mitigation of the consequences. The alarm system is a mandatory component of certified vessels, with direct participation in an accident. It supplies information for the decision making process of the crew, considering their actions to recover the system. The study of the interactions between this automation equipment and the human element on board provides guidelines to managers and owners to invest in proper security systems and policies that influence human behavior, and therefore the safety on board. The model, inspired in accident reports, has as starting point a sequential structure of the accident, and takes into account a typical and simplified sequence of events, starting from a failure in the physical system. The human element is incorporated into the risk analysis through techniques of human reliability analysis, which place man as another component of the system, or the \"liveware\" interacting with software and hardware. From this point of view, a socio-technical approach is applied, considering that a ship is composed of not only its structure and machinery, but also of the entire crew. In order to illustrate the steps and assumptions to be done by an analyst applying the proposed model, the accident of the vessel Maersk Doha, occurred in October of 2006 in the United States, is analyzed. The report on the investigation of this accident is public and accessible via the Internet site of the Marine Accident Investigation Branch MAIB.
15

Funktionsbeskrivning av brandlarmsstyrningen i ventilationssystemet ombord korvett av Göteborgsklass

Jonsson, Jesper January 2010 (has links)
<p>Denna slutrapport beskriver projektarbetet <em>Funktionsbeskrivning av Brandlarms-styrningen av Ventilationssystemet ombord Korvett av Göteborgsklass</em> som beställdes av divisionsingenjören vid 41.korvettdivisionen. Bakgrunden till projektets beställning var att fartygens dokumentation över ventilationssystemets funktion vid brand var bristfällig vilket försvårade underhåll, felsökning och utbildning av och på systemet. Den ofullständiga dokumentationen var ett resultat av att individerna i fartygs­klassen modifierats i flera olika omgångar utan att dokumentationen uppdaterats på ett tillfredsställande sätt. Det hade även framkommit att det fanns olikheter i konfigurationen av fartygsindividernas system.</p><p>Projektet genomfördes dels genom studier av den befintliga dokumentation som fanns att tillgå ombord och på divisionen, dels genom praktiska under­sökningar ombord på fartygen. Under de praktiska undersökningarna framkom behov av ytterligare utredningar än de som ursprungligen framgick av det erhållna uppdraget.</p><p>Projektet påvisade skillnader mellan fartygens system, vissa förmodat felaktiga styr­ningar av fläktar och spjäll samt fastställde att dokumentationen var bristfällig. Projektet resulterade i ett antal beskrivande dokument som sammanställdes i en pärm för respektive fartyg. Dessa uppfyller det givna uppdraget och målen med projektet.</p><p>En större modifiering av fartygen i klassen med syfte att förlänga deras operativa livslängd är under planeringsstadiet. Under modifieringen skall bland annat fartygens dokumen­tation uppdateras, något som resultaten från detta projekt kommer underlätta.</p> / <p>This is the final report regarding the project <em>A Functional Description of the Fire Alarm Con­trol in the Ventilation System aboard the Swedish Navy’s Gothenburg-class Corvettes,</em> wh­­ich was commissioned by the Senior Marine Engineer Officer of the 41st Corvette Sq­­ua­d­ron of the 4th Naval Warfare Flotilla. The reason for the commission was that the set of documentation concerning the function of the ventilation system in case of a fire was insufficient. This caused problems, both during maintenance work done to en­­­su­re that the system was operating in accordance with the design parameters, as well as when trouble-shooting the system. The insufficient set of documentation was a result of a number of upgrades done to the ships over the ye­ars without any corr­e­s­p­on­ding up­date of the documentation. During the project it has also been made clear that there were non-documented differences existing be­­tween the ships in the class.</p><p>The project was fulfilled by a combination of studies of the existing set of do­cumen­tation and practical surveys aboard the ships. During the surveys, more short­comings in the existing set of documentation became evident.</p><p>The project demonstrated differences between the individual ships, assumed inaccuracies in the control of fans and dampers and determined the shortage in the set of documentation. The project has resulted in a number of describing documents that are collected in one unique file for each ship. These documents fulfil the commission and the objectives of the project.</p><p>A major upgrade of the ships in the class with the purpose of extending their operational lifetime is now being planned. The ships’ set of documentation will be simultaneously updated, a task that will be simplified with the support of the results of this project.</p>
16

Análise de risco para embarcações com sistemas de alarmes com foco nos fatores humanos e organizacionais. / Risk analysis for ships with alarm systems, focusing on human and organizational factors.

Luiz Henrique Maiorino Barbarini 11 May 2012 (has links)
Este trabalho apresenta uma proposta de modelo de análise de risco para embarcações, incorporando em sua formulação a influência das interações entre os sistemas de alarmes e os fatores humanos e organizacionais presentes a bordo. De acordo com estatísticas de sociedades classificadoras, o homem é o maior responsável por acidentes marítimos, e, desta forma, é um dos principais componentes da segurança de uma embarcação. A relevância do elemento humano se dá pelo fato de que ações e decisões humanas estão relacionadas tanto à causa, quanto à prevenção de acidentes. O sistema de alarmes é um equipamento de segurança obrigatório, e com direta participação na dinâmica de um acidente, fornecendo informação para a tomada de decisão das ações por parte da tripulação na resolução do problema. O estudo da interação entre este equipamento e o elemento humano a bordo permite a gestores e armadores elaborar diretrizes para investimentos em sistemas de segurança e políticas que influenciam o desempenho humano, e, portanto, a segurança a bordo. O modelo proposto, inspirado em relatório de acidentes marítimos, tem como ponto de partida uma estrutura sequencial do acidente e leva em consideração uma sucessão usual e simplificada dos eventos ocorridos, iniciando a partir de uma falha no sistema físico. O elemento humano, então, é incorporado à análise de risco através das técnicas de análise de confiabilidade humana, as quais têm como princípio a visão do homem como mais um componente do sistema, ou o liveware interagindo com software e hardware. Sob este ponto de vista, uma abordagem sócio-técnica é aplicada, ou seja, considera-se que um navio é composto não apenas de sua estrutura e máquinas, mas também de toda a tripulação. Com o objetivo de exemplificar passos e hipóteses de uma aplicação do modelo proposto, é apresentada a aplicação ao caso do acidente da embarcação Maersk Doha, ocorrido em outubro de 2006 nos Estados Unidos, cujo relatório de investigação do acidente é de acesso público via Internet, no site da Marine Accident Investigation Branch MAIB. / This work presents a risk analysis model for ships, focusing on the scenarios where the crew interacts with the alarm and monitoring system. According to statistics of classification societies, humans are largely responsible for accidents on board and, therefore, are considered a major component of the safety of vessels. The relevance of the human element is given by the fact that human decisions and actions are related to the cause of accidents, either being the direct causative factor of failure or influencing the probability of failure, and the prevention of accidents or mitigation of the consequences. The alarm system is a mandatory component of certified vessels, with direct participation in an accident. It supplies information for the decision making process of the crew, considering their actions to recover the system. The study of the interactions between this automation equipment and the human element on board provides guidelines to managers and owners to invest in proper security systems and policies that influence human behavior, and therefore the safety on board. The model, inspired in accident reports, has as starting point a sequential structure of the accident, and takes into account a typical and simplified sequence of events, starting from a failure in the physical system. The human element is incorporated into the risk analysis through techniques of human reliability analysis, which place man as another component of the system, or the \"liveware\" interacting with software and hardware. From this point of view, a socio-technical approach is applied, considering that a ship is composed of not only its structure and machinery, but also of the entire crew. In order to illustrate the steps and assumptions to be done by an analyst applying the proposed model, the accident of the vessel Maersk Doha, occurred in October of 2006 in the United States, is analyzed. The report on the investigation of this accident is public and accessible via the Internet site of the Marine Accident Investigation Branch MAIB.
17

Softwarová podpora návrhu elektronického zabezpečovacího systému / Software design support of burglar alarm system

Vymazal, Michal January 2009 (has links)
This thesis deals with implementation of software support of alarm system design for security levels 1 and 2 based on web technologies. It was created intuitive and interactive graphical interface that allows to create high-quality alarm system design even for laymen. First of all the paper deals with standards and jurisdictions in the Czech Republic, according to which the alarm system design must be followed. In theoretical part there are described in detail characteristics of alarm systems and its components, proper functioning principles, installation principle, advantages and disadvantages of use, individual steps of alarm system design and proposed methodology of alarm system design for security level 1 and 2. In practical part there are described the technologies used for the implementation of this paper, structure of created webpage and detailed steps of alarm system design, as seen by user during creating. The result of this paper is a webpage, which is divided into two parts: theoretical and practical. The theoretical part provides information about the alarm system architecture, alarm system design and established methodology for the alarm system design for security level 1 and 2. In the practical part the user, on the basis of gained information and interactive help, can create high-quality alarm system design that meets all the conditions for reliable function in real traffic.
18

Hacking Into Someone’s Home using Radio Waves : Ethical Hacking of Securitas’ Alarm System / Hacka in i Någons Hem med hjälp av Radiovågor : Etiskt Hackning av Securitas Hemlarmsystem

Lindeberg, Axel January 2021 (has links)
The number of IoT systems in our homes has exploded in recent years. By 2025 it is expected that the number of IoT devices will reach 38 billion. Home alarm systems are an IoT product that has increased dramatically in number and complexity in recent years. Besides triggering an alarm when an intruder tries to break in, a modern system can now control your light bulbs, lock and unlock your front door remotely, and interact with your smart speaker. They are undeniably effective in deterring physical intrusion. However, given the recent rise in complexity how well do they hold up against cyber attacks? In this thesis, a smart home alarm system from SecuritasHome is examined. A comprehensive security analysis was performed using penetration testing techniques and threat modeling. The work focused mainly on radio frequency (RF) hacking against the systems RF communication. Among other things, a critical vulnerability was found in the proprietary RF protocol, allowing an attacker to disarm an armed system and thus completely bypass the system’s functionality. The security of the system was deemed to be lacking. / Antalet IoT system i våra hem har exploderat de senaste åren. Vid år 2025 förväntas antalet IoT enheter nå 38 miljarder. Hemlarmsystem är en typ av IoT-produkt som ökat dramatiskt i komplexitet på senare tid. Förutom att framkalla ett larm vid ett intrång kan ett modernt hemlamsystem numera kontrollera dina glödlampor, låsa och låsa upp din ytterdörr, samt kontrollera dina övervakningskameror. De är utan tvekan effektiva på att förhindra fysiska intrång, men hur väl står de emot cyberattacker? I denna uppsats undersöks ett hemlarmsystem från SecuritasHome. En utförlig säkerhetsanalys gjordes av systemet med penetrationstestnings-metodiker och hotmodellering. Arbetet fokuserade mestadels på radiovågshackning (RF) mot systemets RF-kommunikation. Bland annat hittades en kritiskt sårbarhet i systemets RF-protokoll som gör det möjligt för en angripare att avlarma ett larmat system, och därmed kringå hela systemets funktionalitet. Säkerheten av systemet bedömdes vara bristfällig.
19

Measuring Speech Intelligibility in Voice Alarm Communication Systems

Geoffroy, Nancy Anne 04 May 2005 (has links)
Speech intelligibility of voice alarm communication systems is extremely important for proper notification and direction of building occupants. Currently, there is no minimum standard to which all voice alarm communication systems must be held. Tests were conducted to determine how system and room characteristics, and the addition of occupants, affect the intelligibility of a voice signal. This research outlines a methodology for measuring the speech intelligibility of a room and describes the impact of numerous variables on these measurements. Eight variables were considered for this study: speaker quantity and location, speaker power tap, sound pressure level (SPL), number and location of occupants, presence of furniture, location of intelligibility measurements, data collection method, and floor covering. All room characteristics had some affect on the room intelligibility; the sound pressure level of the signal and the number and location of occupants had the greatest overall impact on the intelligibility of the room. It is recommended, based on the results of this study, that further investigation be conducted in the following areas: floor finishes, speaker directivity, various population densities, furniture packages and room sizes.
20

Studium interakcí částic kosmického záření při extrémně vysokých energiích / Study of Interactions of Cosmic Rays at Ultra-high Energies

Nečesal, Petr January 2015 (has links)
This thesis is dedicated to study of interactions of utra-high energy cosmic rays using measured data from the Pierre Auger Observatory, automatic alarm system called Shift Guard and analysis of correlation of temperature and detector response. The Pierre Auger Observatory is the largest experiment to study ultra-high energy cosmic rays. The assumed relation between temperature and fluorescence detector response is studied together with descriptive temperature analysis, which shows that the air-conditioning system is not able to stabilize temperature enough. The temperature influence on camera response is investigated in order to measure the calibration correction factor. Shift Guard - the alarm system dedicated to protect fluorescence detectors and data taking is introduced and its functionality is described. The alarm system informs shifters about some events and situations that can endanger detector or deteriorate data quality. The basic parameters and alarm system logic are described together with light and sound signals. The discrepancy between measured and predicted number of muons at ground level calculated by EAS generators is showed and possible sources of this disagree- ment are studied. The result of massive dark photons decay in EAS as one of exotic muon source is presented. The analysis...

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