1. An optical storage device having a lens opposite to a storage medium comprising:
an actuator that moves said lens;
a mechanical shock acceleration sensing unit that senses mechanical shock acceleration;
a collision prevention control unit that drives said actuator for a predetermined period of time with a first driving force greater than a maximum rating force of said actuator when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, that drives said actuator with a second driving force smaller than said maximum rating force of said actuator.
2. The optical storage device as claimed in claim 1, wherein said collision prevention control unit varies the driving force of said actuator from said first driving force to said second driving force through a plurality of steps including said first driving force and said second driving force, each of which has a different force.
3. The optical storage device as claimed in claim 1, wherein said collision prevention control unit varies the driving force of said actuator from said first driving force to said second driving force linearly.
4. The optical storage device as claimed in claim 1, wherein said collision prevention control unit varies the driving force of said actuator from said first driving force to said second driving force at a step.
5. The optical storage device as claimed in claim 1, wherein said actuator has a coil and magnets opposite to said coil,
said collision prevention control unit drives said coil for a predetermined period of time with a first driving current greater than a maximum rating current of said coil when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, drives said coil with a second driving current smaller than said maximum rating current of said coil.
6. The optical storage device as claimed in claim 2, wherein said actuator has a coil and magnets opposite to said coil,
said collision prevention control unit drives said coil for a predetermined period of time with a first driving current greater than a maximum rating current of said coil when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, drives said coil with a second driving current smaller than said maximum rating current of said coil.
7. The optical storage device as claimed in claim 5, wherein said collision prevention control unit varies the driving current of said coil from said first driving current to said second driving current linearly.
8. The optical storage device as claimed in claim 5, wherein said collision prevention control unit varies the driving current of said coil from said first driving current to said second driving current in a step.
9. The optical storage device as claimed in claim 1, wherein said actuator moves said lens in a direction perpendicular to a surface of said storage medium.
10. The optical storage device as claimed in claim 5, wherein said actuator moves said lens in a direction perpendicular to a surface of said storage medium.
11. An optical device comprising:
an actuator that moves a lens;
a mechanical shock acceleration sensing unit that senses mechanical shock acceleration;
a collision prevention control unit that drives said actuator for a predetermined period of time with a first driving force greater than a maximum rating force of said actuator when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, that drives said actuator with a second driving force smaller than said maximum rating force of said actuator.
12. The optical device as claimed in claim 11, wherein said collision prevention control unit varies the driving force of said actuator from said first driving force to said second driving force linearly.
13. The optical device as claimed in claim 11, wherein said collision prevention control unit varies the driving force of said actuator from said first driving force to said second driving force in a step.
14. The optical device as claimed in claim 11, wherein said actuator has a coil and magnets opposite to said coil,
said collision prevention control unit drives said coil for a predetermined period of time with a first driving current greater than a maximum rating current of said coil when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, drives said coil with a second driving current smaller than said maximum rating current of said coil.
15. The optical device as claimed in claim 14, wherein said collision prevention control unit varies the driving current of said coil from said first driving current to said second driving current linearly.
16. The optical device as claimed in claim 14, wherein said collision prevention control unit varies the driving current of said coil from said first driving current to said second driving current in a step.
17. An optical storage device having a lens opposite to a storage medium comprising:
an actuator that moves said lens;
a mechanical shock acceleration sensing unit that senses mechanical shock acceleration;
a collision prevention control unit that drives said actuator with a first driving force greater than a force due to the mechanical shock acceleration when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, that drives said actuator with a second driving force smaller than a maximum rating force of said actuator when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value smaller than said predetermined value.
18. The optical storage device as claimed in claim 17, wherein said collision prevention control unit drives said actuator with another first driving force which force follows said mechanical shock acceleration or which force follows another acceleration that is shifted by the predetermined constant value from said mechanical shock acceleration when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to the predetermined value, and then, drives said actuator with another second driving force smaller than the maximum rating force of said actuator when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value smaller than said predetermined value.
19. The optical storage device as claimed in claim 17, wherein said actuator has a coil and magnets opposite to said coil,
said collision prevention control unit drives said coil with a first driving current that generates a force greater than a force due to the sensed mechanical shock acceleration when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, that drives said coil with a second driving current smaller than a maximum rating current of said coil when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value smaller than the predetermined value.
20. An optical device comprising:
an actuator that moves a lens;
a mechanical shock acceleration sensing unit that senses mechanical shock acceleration;
a collision prevention control unit that drives said actuator with a first driving force greater than the force of the sensed mechanical shock acceleration when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value equal to a predetermined value, and then, that drives said actuator with a second driving force smaller than a maximum rating force of said actuator when said mechanical shock acceleration sensed by said mechanical shock acceleration sensing unit becomes a value smaller than said predetermined value.
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 method of measuring a round trip time (RTT), the method comprising:
(a) chain-hashing at least one random number to create a plurality of hash values;
(b) transmitting one of the created hash values to a device and starting a measurement of the RTT of the device; and
(c) receiving from the device a response to the transmitted hash value and ending the measurement of the RTT.
2. The method of claim 1, wherein, in operation (b), a final hash value among the created hash values is transmitted first.
3. The method of claim 1, wherein, in operation (a), the at least one random number is chain-hashed by a predetermined frequency, and
wherein operations (b) and (c) are repeated by the predetermined frequency.
4. The method of claim 1, further comprising encrypting at least one random number,
wherein, in operation (b), the encrypted random number is transmitted to the device.
5. The method of claim 1, wherein, in operation (a), first and second random numbers are chain-hashed to create hash values of the first and second random numbers,
wherein, in operation (b), one of the hash values of the first random number is transmitted, and
wherein, in operation (c), one of the hash values of the second random number is received in response to the transmitted hash value.
6. The method of claim 1, wherein, in operation (a), a random number is chain-hashed to increase a plurality of hash values,
wherein, in operation (b), one of the hash values of the random number is transmitted, and
wherein, in operation (c), another one of the hash values of the random number is received in response to the transmitted hash value.
7. An apparatus for measuring a round trip time (RTT), the apparatus comprising:
a hasher which chain-hashes at least one random number to create a plurality of hash values;
a transmission and reception unit which transmits one of the created hash values to a device and receives a response to the transmitted hash value from the device; and
an RTT measurer which measures an RTT of the device based on a time when the hash value was transmitted and a time which the response was received by the transmission and reception unit.
8. A non-transitory computer-readable storage medium having embodied thereon a computer program for executing a method of measuring a round trip time (RTT), the method comprising:
chain-hashing at least one random number to create a plurality of hash values;
transmitting one of the created hash values to a device and starting a measurement of an RTT of the device; and
receiving from the device a response to the transmitted hash value and ending the measurement of the RTT.
9. A proximity check method comprising:
(a) chain-hashing at least one random number to create a plurality of hash values;
(b) transmitting one of the created hash values to a device and starting a measurement of a round trip time (RTT) of the device;
(c) receiving from the device a response to the transmitted hash value and ending the measurement of the RTT; and
(d) determining a proximity with the device based on the measured RTT.
10. The proximity check method of claim 9, further comprising authenticating the hash value included in the response,
wherein operation (d) comprises selectively determining the proximity according to a result obtained by the authenticating.
11. A proximity check apparatus comprising:
a hasher which chain-hashes at least one random number to create a plurality of hash values;
a transmission and reception unit which transmits one of the created hash values to a device and receives a response to the transmitted hash value from the device;
a round trip time (RTT) measurer which measures an RTT of the device based on a time transmitted when the hash value was transmitted and a time which the response was received by the transmission and reception unit; and
a proximity determiner which determines a proximity with the device based on the RTT measured by the RTT measurer.
12. A non-transitory computer-readable storage medium having embodied thereon a computer program for executing a proximity check method, the proximity check method comprising:
(a) chain-hashing at least one random number to create a plurality of hash values;
(b) transmitting one of the created hash values to a device and starting a measurement of a round trip time (RTT) of the device;
(c) receiving from the device a response to the transmitted hash value and ending the measurement of the RTT; and
(d) determining a proximity with the device based on the RTT.
13. A method of supporting a round trip time (RTT) measurement, the method comprising:
(a) chain-hashing at least one random number and creating a plurality of hash values,
(b) receiving from a device a hash value corresponding to a start of an RTT measurement of the device; and
(c) transmitting one of the hash values corresponding to an end of the RTT measurement in response to the received hash value.
14. The method of claim 13, wherein, in operation (c), a final hash value among the created hash values is first transmitted.
15. The method of claim 13, further comprising decrypting encrypted random numbers,
wherein, in operation (b), the decrypted random numbers are chain-hashed.
16. The method of claim 13, further comprising authenticating the received hash value,
wherein, in operation (c), the hash value is selectively transmitted according to a result obtained by the authenticating.
17. The method of claim 13, wherein, in operation (a), the random numbers are chain-hashed by a predetermined frequency, and
wherein operations (b) and (c) are repeated by the predetermined frequency.
18. An apparatus for supporting a round trip time (RTT) measurement, the apparatus comprising:
a hasher which chain-hashes at least one random number to create a plurality of hash values; and
a transmission and reception unit which receives from a predetermined device a hash value corresponding to a start of an RTT measurement of the device, and transmits one of the hash values corresponding to an end of the RTT measurement in response to the received hash value.
19. A non-transitory computer-readable storage medium having embodied thereon a computer program for executing a method of supporting a round trip time (RTT) measurement, the method comprising:
chain-hashing at least one random number and creating a plurality of hash values,
receiving from a device a hash value corresponding to a start of an RTT measurement of the device; and
transmitting one of the hash values corresponding to an end of the RTT measurement in response to the received hash value.