Glossary

Glossary

Data authentication

Measures taken to ensure that the integrity of the data from the monitoring stations in the International Monitoring System network has not been compromised, either accidentally or maliciously, by some action at the station or in transmission to the International Data Centre, or at any time thereafter.

Data availability

The percentage of the data, on time or delayed, that reaches the International Data Centre per year.

Data availability requirements

Requirements as specified by the CTBT that dictate successful collection and transmission of data to the Central Recording Facilities and the National Data Center.

Data buffer

A temporary record of station data maintained at the station or a National Data Centre or an appropriate communication node to minimize loss of data during a period of communication outage with the International Data Centre.

Data fusion

The joined analysis of waveform, most often seismic, and radionuclide data. Location information from both types of data is overlaid to identify a common area as the source location of an event.

Data latency

Data Latency is the difference in time between when a monitoring station acquires data and the time at which the International Data Centre receives the data for analysis. 

Data mining

Modern IT-based analysis methods for large amount of data.

Daytime convection

Related to infrasound monitoring, daytime convection is a term used to describe the generation of thermal plumes induced by solar heating of the earth’s surface during the day. The onset of thermal activity during the early daylight hours destroys the stable nocturnal boundary layer, thus re-connecting the ambient winds to the surface.

De-activate

To remove a weapon from operational status for an indefinite period. Used synonymously with "de-alert" in referring to nuclear missiles.

De-alert

To reduce the level of readiness to launch of nuclear weapons systems. Measures include removing nuclear warheads from missiles and storing the warheads separately from the missiles.

Deterrence

The actions of a state or group of states to dissuade a potential adversary from initiating an attack or conflict by the threat of retaliation. Deterrence should credibly demonstrate to an adversary that the costs of an attack would be too great and would outweigh any potential gains or, in nuclear terms that the costs would involve massive destruction from a nuclear strike.

Deterrent

Same as Deterrence

Diffusion

A technique for uranium enrichment in which the lighter Uranium 235 isotopes in UF6 gas move through a porous barrier more rapidly than the heavier Uranium 238 isotopes.

Digitizer

A device that converts analog signals into digital signals by taking discrete individual samples of the continuous analog signal in order to approximate the analog signal. With this collection of samples, the digitizer then allows the approximation of the analog signal to be analyzed, processed or stored as necessary.

Dual-use item

An item that has both civilian and military applications. Some examples from the nuclear field include radioisotopes used in the treatment of cancer, the operation of uranium mines and refineries, and the use of radioactive sources for oil exploration and in instruments such as precipitation measurement devices.