1. A method comprising:
receiving an update at a domain name system (DNS) server from a first client device, the update including a host name;
determining whether the DNS server hosts an authoritative zone for the update;
determining whether there is already a record for the host name; and if so,
determining an Internet Protocol (IP) address associated with the host name;
determining whether the IP address associated with the host name matches a source IP address of the first client device; and
accepting the update if the IP addresses match.
2. The method of claim 1, further comprising accepting the update if there is no record for the host name.
3. The method of claim 1, further comprising sending a DNS query to a second client device having the IP address associated with the host name if the IP address associated with the host name does not match the source IP address of the first client device.
4. The method of claim 3, further comprising rejecting the update if an acknowledgement is received from the second client device in response to the DNS query.
5. The method of claim 3, further comprising accepting the update if no acknowledgement is received from the second client device in response to the DNS query.
6. The method of claim 1, further comprising replicating the update to another DNS server.
7. The method of claim 1, wherein determining whether there is already a record for the host name comprises checking multiple records of multiple types.
8. The method of claim 7, wherein one of the record types is an Address (A) record.
9. The method of claim 7, wherein one of the record types is an IPv6 address record.
10. The method of claim 7, wherein one of the record types is a Canonical Name (CNAME) record.
11. The method of claim 1, wherein the zone is file-backed.
12. The method of claim 1, wherein the zone is integrated with a directory system.
13. One or more device-readable media with device-executable instructions for performing steps comprising:
receiving an update from a first client device at a domain name system (DNS) server that hosts an authoritative zone for the update, the update including a host name;
checking one or more records in the zone to determine whether there is already a record for the host name, and if so,
checking the record for the host name to determine an Internet Protocol (IP) address associated with the host name;
determining whether the IP address associated with the host name matches a source IP address of the first client device, and if not,
sending a DNS query to a second client device having the IP address associated with the host name; and
determining whether to accept the update based on whether the second client device responds to the DNS query.
14. The one or more device-readable media of claim 13, wherein the steps further comprise accepting the update if there is no record for the host name.
15. The one or more device-readable media of claim 13, wherein the steps further comprise accepting the update if the IP address associated with the host name matches the source IP address of the first client device.
16. The one or more device-readable media of claim 13, wherein determining whether to accept the update based on whether the second client device responds to the DNS query comprises rejecting the update if the second client device responds to the DNS query and accepting the update if the second client device does not respond to the DNS query.
17. A method comprising:
receiving an update from a first client device at a domain name system (DNS) server, the update including a host name;
determining whether there is already a record for the host name; and if so,
determining a source IP address of a registrant of the host name;
determining whether the source IP address of the registrant of the host name matches the first client device’s source IP address, and if not,
sending a DNS query to the registrant of the host name; and
rejecting the update if an acknowledgement is received from the registrant in response to the DNS query.
18. The method of claim 17, further comprising accepting the update if there is no record for the host name.
19. The method of claim 17, further comprising accepting the update if the source IP address of the registrant of the host name matches the first client device’s source IP address.
20. The method of claim 17, further comprising accepting the update if no response is received from the registrant in response to the DNS query.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A magnetic resonance (MR) system comprising:
a driving module configured to apply a perturbation to a sample;
a processor configured to generate RF modulated pulses, the RF modulated pulses configured to define a plurality of at least three different rotating frames of reference relative to the perturbation, the plurality of at least three different rotating frames of reference including at least two frames in which each frame of the at least two frames includes a fictitious field and wherein at least one fictitious field is time variant, the fictitious fields are produced by an interaction of the plurality of the at least three different rotating frames of reference, and each different rotating frame is associated with an effective field, wherein the fictitious fields and the effective fields are associated with the generated modulated pulses and the modulated pulses are produced by a recursive expansion; and
a readout module coupled to the processor and configured to generate an output based on a relaxation of spins of the sample as a function of the perturbation in order to display or store a magnetic resonance output with the readout module.
2. The system of claim 1 wherein the processor is configured to generate a frequency swept pulse, wherein the frequency swept pulse corresponds to a modulated pulse of the generated modulated pulses.
3. The system of claim 1 wherein the driving module is configured to deliver a frequency swept pulse, wherein the frequency swept pulse corresponds to a modulated pulse of the generated modulated pulses.
4. The system of claim 1 wherein the driving module is configured to apply a pulse train, wherein the pulse train corresponds to the generated modulated pulses.
5. The system of claim 1 wherein the processor is configured to instantaneously flip a magnetization of the fictitious field.
6. The system of claim 1 further including at least one of a display or a printer that is coupled to the readout module, wherein the display or the printer is configured to render a visible image corresponding to the output from the readout module.
7. The system of claim 1 wherein at least one rotating frame of reference of the spin system includes modulation of amplitude or frequency based on a tangent function.
8. A magnetic resonance method comprising:
applying a perturbation to a system;
generating RF modulated pulses, the RF modulated pulses configured to define a plurality of at least three different rotating frames relative to the perturbation, the plurality of at least three different rotating frames including at least two frames in which each frame of the at least two frames includes fictitious field and wherein at least one fictitious field is time dependent, the fictitious fields produced by interaction of the plurality of at least three different rotating frames, and wherein each different rotating frame is associated with an effective field and wherein the fictitious fields and the effective fields are associated with the modulated pulses and the modulated pulses are produced by a recursive expansion; and
applying a readout module to the system after applying the perturbation in order to display or store a magnetic resonance output with the readout module.
9. The method of claim 8 wherein applying the perturbation to the system includes applying a magnetic perturbation to a spin system using a magnetic resonance system.
10. The method of claim 8 wherein at least one fictitious field remains constant in the at least one rotating frame of the at least three different rotating frames.
11. The method of claim 8 further including decreasing a relaxation of the spin system in a selected rotating frame of the plurality of at least three different rotating frames.
12. The method of claim 8 further including generating a rotating frame rotary echo in the spin system using a magnetic resonance system.
13. The method of claim 8 further including locking a magnetization of the system to a fictitious field of a selected rotating frame of the at least three different rotating frames.
14. The method of claim 8 further wherein at least one fictitious field is non-stationary.
15. The method of claim 8 wherein applying the perturbation to the system includes applying a frequency swept pulse.
16. The method of claim 8 wherein at least one fictitious field of the system remains constant in amplitude.
17. The method of claim 8 wherein at least two of the fictitious fields of the system are time dependent.
18. The method of claim 8 wherein at least one fictitious field of the system remains constant in a direction.
19. A non-transitory processor-implemented method which, when executed, causes a magnetic resonance system to generate a magnetic resonance image, the method comprising:
selecting a rank for a fictitious frame of reference that images a region of interest in a spin system, wherein the selected rank corresponds to at least three different fictitious frames of reference;
generating a sequence of modulated pulses that excites the spin system with the sequence of modulated pulses having a sweeping frequency and both a modulated amplitude and phase in which the effective field varies with time in the fictitious frame, wherein the effective field is associated with the sequence of modulated pulses and wherein the sequence of modulated pulses are produced by a recursive expansion;
acquiring magnetic resonance data corresponding to the spin system, the data corresponding to relaxation of spins in the region of interest based on excitation from the sequence of modulated pulses; and
generating an MR image with a processor based on the acquired data.
20. The method of claim 19 wherein the sequence of modulated pulses includes at least one pulse that is sub-adiabatic.
21. The method of claim 19 wherein the rank is greater than 2.
22. A magnetic resonance (MR) system comprising:
a driving module configured to apply a perturbation to a sample;
a processor configured to generate modulated pulses to define at least n different rotating frames of reference where n is an integer of at least three, the rotating frames of reference including at least n\u22121 frames in which each of the n\u22121 frames includes a fictitious field and wherein at least one fictitious field is time variant, the fictitious fields produced by interaction of the plurality of at least n different rotating frames of reference, and wherein each different rotating frame of reference is associated with an effective field and wherein the fictitious fields and the effective fields are associated with the modulated pulses and the modulated pulses are produced by a recursive expansion; and
a readout module coupled to the processor and configured to generate an output based on relaxation of spins of the sample as a function of the perturbation that is displayed or stored by the MR system.