<p>Vattenfall and Svenska Kraftnät perform start-up tests, where hydropower generators are used to power up the electrical grid in case of a blackout. To monitor the electrical grid, Phasor Measurement Units (PMU) are used. Each PMU is individually equipped with a GPS-receiver to precisely timestamp the data relative to the official time UTC. During the test, it is also of interest to timestamp the measurement signals from individual hydropower generators to later compare with PMU-data, and thus study the power grids impact on the generator.</p><p> </p><p>The aim is to work out an appropriate method to make these measurements and to build a data acquisition system, capable of timestamp data relative to UTC, from a generator in one of Vattenfalls hydroelectric power stations. The problem is that the generator is located in an underground station which hampers the reception of GPS-signals and wiring should be avoided if possible.</p><p> </p><p>Time synchronization has been solved by using Vattenfalls network, which is synchronized by the network protocol NTP. The network includes the concerned hydropower stations and thus can wiring from the surface be avoided. The maximum error for the server in the specific hydroelectric power station is bounded within [-4.62, 3.18] ms relative to UTC. The conclusion is that Vattenfalls NTP-network meets the requirements to distribute time. A platform from National Instruments, programmed with the graphical language LabVIEW, has been used for data acquisition. The platform is programmed to synchronize its internal clock to a NTP-server, timestamp the input signals and save the data on the internal hard drive.</p>

Vattenfall and Svenska Kraftnät perform start-up tests, where hydropower generators are used to power up the electrical grid in case of a blackout. To monitor the electrical grid, Phasor Measurement Units (PMU) are used. Each PMU is individually equipped with a GPS-receiver to precisely timestamp the data relative to the official time UTC. During the test, it is also of interest to timestamp the measurement signals from individual hydropower generators to later compare with PMU-data, and thus study the power grids impact on the generator.   The aim is to work out an appropriate method to make these measurements and to build a data acquisition system, capable of timestamp data relative to UTC, from a generator in one of Vattenfalls hydroelectric power stations. The problem is that the generator is located in an underground station which hampers the reception of GPS-signals and wiring should be avoided if possible.   Time synchronization has been solved by using Vattenfalls network, which is synchronized by the network protocol NTP. The network includes the concerned hydropower stations and thus can wiring from the surface be avoided. The maximum error for the server in the specific hydroelectric power station is bounded within [-4.62, 3.18] ms relative to UTC. The conclusion is that Vattenfalls NTP-network meets the requirements to distribute time. A platform from National Instruments, programmed with the graphical language LabVIEW, has been used for data acquisition. The platform is programmed to synchronize its internal clock to a NTP-server, timestamp the input signals and save the data on the internal hard drive.

<p>This  report  is  a  part  of  a  master  thesis  project  done  at  Ericsson  Linköping  incooperation with Linköpings Tekniska Högskola (LiTH). This project is divided intwo different parts.  The first part is to create a measurement node that collectsand processes data from network time protocol servers.   It is used to determinethe  quality  of  the  IP  network  at  the  node  and  detect  potential  defects  on  usedtimeservers or nodes on the networks.The second assignment is to analyze the collected data and further improve theexisting synchronization algorithm.  Ip communication is not designed to be timecritical and therefore the NTP protocol needs to be complemented with additionalsignal processing to achieve required accuracy.  Real time requirements limit thecomputational complexity of the signal processing algorithm.</p>

This  report  is  a  part  of  a  master  thesis  project  done  at  Ericsson  Linköping  incooperation with Linköpings Tekniska Högskola (LiTH). This project is divided intwo different parts.  The first part is to create a measurement node that collectsand processes data from network time protocol servers.   It is used to determinethe  quality  of  the  IP  network  at  the  node  and  detect  potential  defects  on  usedtimeservers or nodes on the networks.The second assignment is to analyze the collected data and further improve theexisting synchronization algorithm.  Ip communication is not designed to be timecritical and therefore the NTP protocol needs to be complemented with additionalsignal processing to achieve required accuracy.  Real time requirements limit thecomputational complexity of the signal processing algorithm.

Detta arbete behandlar en specifik typ av överbelastningsattack som blir allt mer populär. Dessa attacker utförs genom öppna reläer med syftet att få ut en avsevärt mycket högre effekt än den som annars är uppnåbar. Granskning av attacker utförda genom tjänsterna DNS och NTP har utförts med syftet att ge en klar bild av hur allvarligt hotet är och även klargöra hur en systemadministratör kan säkra tjänsterna för att skydda både sina egna och andras resurser. Resultaten av undersökningar visar att en attack utförd genom en DNS-tjänst ger under optimala förhållanden en amplifikationsfaktor av "102.4" och en attack genom en NTP-tjänst ger under optimala förhållanden en amplifikationsfaktor av "229.16". Resultaten visar även att problemet kan lösas helt eller delvis genom att begränsa tillåtna nätverk eller stänga av rekursion i DNS och kommandon i NTP. / This work concerns a specific type of Denial of Service attack which is becoming increasingly popular. These attacks are carried out through open relays with the purpose of getting a significantly higher effect than otherwise achievable. Examination of attacks carried out through the services DNS and NTP have been conducted with the purpose of providing a clear picture of how serious the threat is and also clarify how a system administrator can secure the services to protect both their own and others resources. The results of our studies show that an attack performed through a DNS service gives under optimal conditions a amplification factor of "102.4" and an attack through a NTP service gives under optimal conditions a amplification factor of "229.16". The results also show that the problem can be solved in whole or in part by limiting the allowed network or disable recursion in DNS and commands in NTP.

Made available in DSpace on 2014-06-12T15:58:39Z (GMT). No. of bitstreams: 2 arquivo4665_1.pdf: 1244503 bytes, checksum: 9601c55f303bf34b27c25d55062533b9 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2003 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O Network Time Protocol (NTP) é um protocolo para sincronização de relógios de computadores em rede que tem quase duas décadas de existência e está em contínua evolução. Com algoritmos robustos para tratamento de fase e freqüência, com um bom disciplinador de relógio local e tendo implementações para as mais diversas plataformas e sistemas operacionais de computadores e equipamentos de rede, o NTP tornou-se um padrão de fato. Entretanto, esse protocolo ainda tem problemas que precisam ser solucionados para ser operacionalmente eficaz, pois seu desempenho depende de boas condições de rede para a troca das informações de sincronização, sofrendo bastante em caso de congestionamento. Devido a esses problemas, em vários países (incluindo o Brasil) esse protocolo é considerado inadequado para prover informação de horário de forma confiável, fazendo com que registros de hora em sistemas que o utilizam não tenham valor legal. Além disso, muitas aplicações necessitam de um sistema de controle de relógios confiável para funcionar corretamente (por exemplo, sistemas bancários e servidores de bancos de dados distribuídos). Isso obriga muitas empresas a utilizar sistemas legados tradicionais e mais caros para poder funcionar de forma correta e legal. Com o advento da Qualidade de Serviço em redes de computadores, esse problema pode ser abordado elegantemente e resolvido. Várias arquiteturas de Qualidade de Serviço foram propostas, mas a arquitetura de Serviços Diferenciados (DiffServ), devido a sua facilidade de implementação e ao fato de ter sido a mais estudada e implementada experimentalmente, mostrou-se a mais forte candidata à implantação mundial e no menor prazo. Essa arquitetura adequou-se bem ao problema de sincronização de relógios, embora a solução não seja trivial. Essa dissertação sugere um arcabouço para lidar com a sincronização de relógios através do NTP em domínios DiffServ com ou sem corretores de banda. Tendo-se Serviços Bem Definidos (Well Defined Services WDS) e baseado na idéia de que as aplicações devem conhecer o tipo de tratamento necessário ao seu tráfego, esse arcabouço consiste na adoção de políticas para o tratamento de tráfego NTP nos equipamentos de rede e na adoção de uma política para a marcação de pacotes por parte da aplicação. A proposta é validada com um estudo de caso feito com medição real do desempenho da aplicação sobre um ambiente de rede emulado

Realizar los ensayos a la compresión y verificar la veracidad de los resultados que encontramos diariamente en libros, revistas y otros medios que no tienen ninguna alidación por la NTP (Norma Técnica Peruana), de esta manera se elaborará mezclas de concreto de 5 relaciones a/c diferentes, utilizando cemento pórtland Tipo I con agregados según indica la Norma Técnica Peruana

La Presidencia de Consejo de Ministros (PCM) emitió un conjunto de normas entre ellas algunas relacionadas a la seguridad de la información, con la cual se dispuso la obligatoriedad de uso de la NTP ISO/IEC 27001:2008 (aprobada con RM Nº 129-2012- PCM del 4 de junio de 2012), posteriormente la Norma Técnica Peruana NTP-ISO /IEC 27001:2014 2da Edición (aprobada con RM N° 004-2016-PCM del 8 de enero de 2016). Sin embargo, han pasado 6 años desde entonces, y pocas entidades han logrado la implementación total de la norma, es por ello que este trabajo de investigación tiene como objetivo identificar estos factores de éxito o limitantes para la implementación de la norma. La investigación se desarrolló en la Municipalidad Provincial de Huancayo, para lo cual elabore un check list en base a lo que solicita la norma y verifique la existencia en la Municipalidad durante I trimestre del año 2018, cualquiera fuese el resultado se solicitó información de los factores que permitieron el nivel alcanzado. Al finalizar la investigación se identificó que la entidad implemento 32% de lo solicitado por la norma, que algunos de los factores de éxito fue el conocimiento, experiencia e interés por parte del funcionario público responsable, y entre los limitantes la falta de procesos, cultura organizacional, presupuesto y capacitaciones.

This diploma thesis concerns design and creation of a navigational system as a tool for pilots of helicopters and ultralight planes. Choosing required functions is critical part for realization of this project. The paper also contains description of draft of application.

The reliable internet stream transport (RIST) protocol is used for streaming video over the internet and requires time synchronisation to ensure that each frame is played out at the correct time. One method to ensure time synchronisation today in RIST productions is by utilizing the network time protocol (NTP). NTP has several issues and requirements that makes it a not ideal time synchronisation method in RIST productions and this thesis proposes a dynamic average time synchronisation (DATS) method as an option for using NTP in RIST productions. The DATS method uses a two-way synchronisation scheme to estimate the time offset between a video sender node and a video receiver node which is added to an average used as the time offset value. Additionally, it is explored whether or not a Kalman filter can further increase performance in DATS. Furthermore, the Kalman filter parameters were attempted to be optimized with a genetic algorithm. With a simulated \textit{testsrc FFmpeg} stream, the performance of DATS is evaluated and compared with the NTP implementation \textit{Chrony}. The metrics used in the evaluation was the playout delay and the error in time synchronisation which were calculated by periodical messages between a sender and receiver node. The results reveal that DATS performs slightly better without a Kalman filter but is slightly less robust without it. The results also indicated that DATS is comparable to NTP in an unloaded network, but is outperformed by NTP in a congested network.