Random Knowledge Flashcards
(12 cards)
La latence est le délai de transmission des données, ou le délai entre une requête et une réponse. Elle mesure le temps nécessaire à une action après son déclenchement. Une faible latence indique un système plus rapide et plus réactif, tandis qu’une latence élevée suggère un système plus lent et moins réactif.
Latency is the time delay experienced when data travels from one point to another, or the delay between a request and a response. In essence, it measures how long it takes for something to happen after it’s initiated. A low latency indicates a faster, more responsive system, while high latency suggests a slower, less responsive system.
A tecnologia 4G, oficialmente conhecida como International Mobile Telecommunications-Advanced (IMT-Advanced), requer taxas de dados de pico de 100 Mbps para alta mobilidade (como em trens) e 1 Gbps para baixa mobilidade (como usuários estacionários). Além disso, os sistemas 4G precisam ser baseados em uma rede de comutação de pacotes totalmente IP e oferecer suporte a recursos como transições suaves entre diferentes redes e serviços multimídia de alta qualidade
4G technology, officially known as the International Mobile Telecommunications-Advanced (IMT-Advanced), requires peak data rates of 100 Mbps for high mobility (like on trains) and 1 Gbps for low mobility (like stationary users). Additionally, 4G systems need to be based on an all-IP packet-switched network and support features like smooth transitions between different networks and high-quality multimedia services
L’induttanza è la caratteristica di un circuito elettrico che si oppone all’avvio, all’arresto o a una variazione di valore della corrente.
Inductance is the characteristic of an electrical circuit that opposes the starting, stopping, or a change in value of current.
Il simbolo dell’induttanza è L e l’unità di misura fondamentale dell’induttanza è l’HENRY (H). Un henry è pari all’induttanza necessaria per indurre un volt in un induttore con una variazione di corrente di un ampere al secondo.
The symbol for inductance is L and the basic unit of inductance is the HENRY (H). One henry is equal to the inductance required to induce one volt in an inductor by a change of current of one ampere per second.
Ingénierie des postes électriques, page 308/524
15.9.1 Attaques contre la sécurité des systèmes SCADA
Le secteur reconnaît plusieurs types de failles de sécurité auxquelles les systèmes SCADA peuvent être vulnérables. En voici la liste :
* Violation d’autorisation : un utilisateur autorisé exécute des fonctions dépassant son niveau d’autorité.
* Écoute clandestine : collecte d’informations non autorisées en écoutant des communications non protégées.
* Fuite d’informations : des utilisateurs autorisés partagent des informations avec des tiers non autorisés.
* Interception/Altération : un attaquant s’introduit (logiquement ou physiquement) dans une connexion de données, puis intercepte et modifie les messages à ses propres fins.
Usurpation d’identité : un intrus se fait passer pour une entité autorisée et accède ainsi à un système.
* Rejeu : un intrus enregistre un message légitime et le rejoue à un moment inopportun.
Un exemple souvent cité est l’enregistrement de la transmission radio utilisée pour activer les sirènes d’alerte de sécurité publique lors d’une transmission test, puis la retransmission du message ultérieurement. Une attaque de ce type ne nécessite qu’une compréhension très rudimentaire du protocole de communication.
* Attaque par déni de service : un intrus attaque un système en consommant une ressource système critique, de sorte que les utilisateurs légitimes ne sont jamais ou rarement servis.
Substation Engineering Pg 308/524
15.9.1 SCADA Security Attacks
A number of types of security challenges to which SCADA systems may be vulnerable are recognized in
the industry. The list includes the following:
* Authorization violation: An authorized user performing functions beyond his level of authority.
* Eavesdropping: Gleaning unauthorized information by listening to unprotected communications.
* Information leakage: Authorized users sharing information with unauthorized parties.
* Intercept/alter: An attacker inserting himself (either logically or physically) into a data connection
and then intercepting and modifying messages for his own purposes.
Masquerade (Spoofing): An intruder pretending to be an authorized entity and thereby gaining
access to a system.
* Replay: An intruder recording a legitimate message and replaying it back at an inopportune time.
An often-quoted example is recording the radio transmission used to activate public safety warning
sirens during a test transmission and then replaying the message sometime later. An attack
of this type does not require more than very rudimentary understanding of the communication
protocol.
* Denial-of-service attack: An intruder attacking a system by consuming a critical system resource
such that legitimate users are never or infrequently serviced.
Ingeniaria Transmissionis Pagina 324
Quattuor modi diversi
emissionis coronae, distinctas proprietates electricas, physicas et visuales habentes, observari
possiunt apud anodum valde tensum, ante eruptionem fulminantem hiatus. Hi sunt, respective, cum crescente
intensitate campi (Figura 16.5): corona eruptionis, flammae incipientes, lumen positivum, et flammae disruptionis.
Transmission Engineering Pg 324
Four different
corona discharge modes having distinct electrical, physical, and visual characteristics can be
observed at a highly stressed anode, prior to flashover of the gap. These are, respectively, with increasing
field intensity (Figure 16.5): burst corona, onset streamers, positive glow, and breakdown streamers.
Las cataratas se desarrollan en perros por etapas:
Etapa 1: Cataratas incipientes.
Etapa 2: Cataratas inmaduras.
Etapa 3: Cataratas maduras.
Etapa 4: Cataratas hipermaduras.
Cataracts develop in dogs in stages
Stage 1 - Incipient cataracts.
Stage 2 - Immature cataracts.
Stage 3 - Mature cataracts.
Stage 4 - Hypermature cataracts.
Las cataratas podrían estar relacionadas con la demencia.
Las personas mayores que se someten a una cirugía de cataratas tienen menos probabilidades de desarrollar demencia posteriormente.
Source: New Scientist, 12/18/2021
Cataracts may be linked to dementia.
OLDER people who have cataract surgery are less likely to develop dementia afterwards.
Birds create several problems when entering an electrical substation. The first and most obvious is
the bridging between phase to ground or phase to phase caused by the wingspan when flying into or
exiting the structure. Another problem is the bridging caused by debris used to build nests. Many
times material such as strands of conductors or magnetic recording tape may be readily available
from the surrounding area and be utilized by the birds. This conductive debris is often dragged
across the conductor/busbar and results in flashovers, trips, or faults. The third problem is contamination of insulators caused by regurgitation or defecation of the birds. When this residue is allowed
to remain, it can result in flashovers from potential to ground across the surface of the porcelain
or polymer insulator by essentially decreasing the insulated creepage distance. The fourth possibility is commonly known as a “streamer outage.” Streamers are formed when a bird defecates upon
exiting a nest that has been built above an insulator. The streamers may create a path between the
structure and conductor/bus, resulting in a flashover. Birds will tend to make nests in substations in
an effort to eliminate possible predators from attacking the nest for food. The construction of nests
in substations can, in turn, attract other animals such as snakes, cats, and raccoons into the area
searching for food
Aves plura problemata creant cum substationem electricam ingrediuntur. Primum et manifestissimum est pontem inter phasem et terram vel inter phasem et phasim, quod a longitudine alarum causatur cum in structuram volant vel ex ea exeunt. Aliud problema est pontem a fragmentis ad nidos construendos adhibitis causatum. Saepe materia, ut fila conductorum vel taeniae magneticae, facile ex area circumstanti praesto esse potest et ab avibus adhiberi. Haec fragmenta conductiva saepe trans conductorem/vectem communem trahuntur et in fulgurationibus electricis, impedimentis, vel vitiis resultant. Tertium problema est contaminatio insulatorum, quae a regurgitatione vel defecatione avium causatur. Cum hoc residuum manere permittitur, fulgurationes electricas a potentia ad terram trans superficiem insulatoris porcellani vel polymerici efficere potest, distantiam penetrationis insulati essentialiter minuendo. Quarta possibilitas vulgo “interruptio fluminis” appellatur. Flumina formantur cum avis defecat cum ex nido supra insulatorem constructum exit. Vibrae viam inter structuram et conductorem/bus creare possunt, quod fulgurationem electricam efficit. Aves nidos in substationibus facere solent,
ut praedatores potentiales a nido cibo petendis oppugnando excludant. Constructio nidorum
in substationibus vicissim alia animalia, ut serpentes, feles, et procyones, in aream
cibum quaerentes, allicere potest.
A síndrome do impostor pode ser muito debilitante
Daily Telegraph (London), May 03, 2025,
Imposter syndrome can be very debilitating
VEER - Allow a line, wire, or chain to run out by its own weight, as to veer cable by
slacking the brake on a disconnected windlass.
VIRAR - Dejar que una línea, cable o cadena se deslice por su propio peso, como para virar un cable aflojando el freno de un molinete desconectado.
Vexilla in chartis argentariis:
Vexillologia cum
Notaphilia occurrit
Flags on Banknotes:
Vexillology Meets
Notaphily
