Multi-device powersaving

• US 9,026,825 B2
• Filed: 12/01/2011
• Issued: 05/05/2015
• Est. Priority Date: 12/01/2011
• Status: Expired due to Fees

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Andreoli, Jean-Marc, Bouchard, Guillaume M.
• Primary Examiner(s): Huynh, Kim
• Assistant Examiner(s): YEN, PAUL JUEI-FU
• Application Number:
  US13/308,780
• Publication Number:
  US 20130145187A1
• Time in Patent Office: 1,251 Days
• Field of Search: 713/300, 713/310, 713/320, 713/321, 713/322, 713/323, 713/324, 713/330, 713/340, 713/375, 713/1, 713/2, 713/100
• US Class Current: 713/323
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode
• CPC Class Codes: G06F 1/3284 Power saving in printer
• CPC Class Codes: G06F 3/1221 with regard to power consumption
• CPC Class Codes: G06F 3/126 Job scheduling, e.g. queuing, determine appropriate device
• CPC Class Codes: G06F 3/1291 Pool of printer devices: self-managing printing devices in a network, e.g. without a server
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A control system reduces energy consumption in a multi-device system comprising a plurality of devices. The control system includes at least one processor. The processor is programmed to receive a job to be executed, as well as a selection of one of the plurality of devices for executing the job and a transfer cost for transferring the job from the selected device to each of the plurality of devices. A device to execute the job is determined through optimization of a first cost function. The first cost function is based on the device selection and the transfer costs. The job is assigned to the determined device and a time-out for each device in the multi-device system is determined through optimization of a second cost function. The second cost function is based on an expected energy consumption by the multi-device system. The devices are provided with the determined time-outs.

Claims

1. A control system for reducing energy consumption in an associated multi-device system comprising a plurality of devices, said energy control system comprising:

at least one processor programmed to;

receive a job to be executed;

receive a selection of one of the plurality of devices for executing the job and a transfer cost for transferring the job from the selected device to each of the plurality of devices;

determine a device from the plurality of devices to execute the job through optimization of a first cost function, the first cost function based on the device selection and the received transfer costs;

assign the job to the determined device;

determine a time-out for each device in the multi-device system through optimization of a second cost function, the second cost function based on an expected energy consumption by the multi-device system; and

,

provide the devices with the determined time-outs;

wherein at least one of the device and the time-outs are determined by modeling a control problem as a Markov Decision Process (MDP), the MDP including the first cost function and the second cost function, wherein at least one of;

a) the first cost function in an optimal regime is computed according to the expression;

V_hσ

,z=min_kR_hk+(1−

σ

_k){circumflex over (b)}_kVσ

+(1−

σ

_k)e_k,z 

 

(19)

where k is one of the plurality of devices;

h is the selected one of the plurality of devices;

R_hk is the transfer cost for device k;

{circumflex over (b)}_k is the cost of transitioning device k from a first mode to a second mode, the second mode consuming more power than the first mode;

a is a control state vector of the multi-device system, each k-th component indicating a state for device k, where a value of 0 corresponds to the first mode and 1 corresponds to the second mode;

z is a demand state of the multi-device system;

σ

,z is a state of the multi-device system;

e_k is a vector of Os for each component except the k-th component, which is 1; and

V is the second cost function; and

b) the second cost function in an optimal regime is computed according to the expression;

2. The control system according to claim 1, wherein the transfer cost for a device is the cost to a user from executing the job on the device in terms of reduction in print quality.

3. The control system according to claim 1, wherein the time-out for a device is the time for which the device remains in a first mode, after a job is completed, before moving to a second mode, which consumes less energy, in the absence of the arrival of another job.

4. The control system according to claim 1, wherein the time-out for a device is based on an estimation of demand for the devices and transfer costs between the devices.

5. The control system according to claim 1, wherein the expected energy consumption is based on probability distributions for device selections and times between jobs received by the plurality of devices.

6. The control system according to claim 5, wherein the probability distributions are computed for different demand states of the multi-device system.

7. The control system according to claim 1, wherein the MDP is solved using a value-iteration method.

8. The control system according to claim 1, wherein the optimization of the second cost function is reduced to a bounded sequence of one dimensional optimizations.

9. The control system according to claim 1, wherein the first cost function and the second cost function are minimized at least partially in a selected function space.

10. A multi-device print system comprising the control system of claim 1 and a plurality of the devices, the devices being print devices.

11. The system according to claim 1, wherein the at least one processor is further programmed to:

receive the job, the selection, and the transfer cost, from a remote device over a communications network.

12. The system according to claim 1, wherein the expected energy consumption is the combined energy consumption expected of all of the plurality of devices.

13. The control system according to claim 1, wherein the at least one processor is further programmed to at least one of:

determine a globally optimal device from the plurality of devices to execute the job through optimization of the first cost function; and

determine a globally optimal time-out for each device in the multi-device system through optimization of the second cost function, the time-out for each device being the time for which the device remains in a first mode, after a job is completed, before moving to a second mode, which consumes less energy, in the absence of the arrival of another job.

14. A method for reducing energy consumption in a multi-device system comprising a plurality of devices, said method comprising:

receiving a job to be executed;

receiving a selection of one of the plurality of devices for executing the job and a transfer cost for transferring the job from the selected device to each of the plurality of devices;

determining a device from the plurality of the devices to execute the job through optimization of a first cost function, the first cost function based on the device selection, the received transfer costs, and power consumption costs of transitioning devices of the plurality of devices between different energy consumption modes;

assigning the job to the determined device;

determining a globally optimal time-out for each device in the multi-device system through optimization of a second cost function, the time-out for each device being the time for which the device remains in a first of the energy consumption modes, after a job is completed, before moving to a second of the energy consumption modes, which consumes less energy, in the absence of the arrival of another job, the second cost function being based on an expected energy consumption by the multi-device system; and

,

providing the devices with the determined time-outs;

wherein the expected energy consumption is based on probability distributions for device selections and times between jobs; and

wherein at least one of the determining of the device and the determining of the time-outs includes;

modeling a control problem as a Markov Decision Process (MDP), the MDP including the first cost function and the second cost function and wherein at least one of;

a) the first cost function in an optimal regime is computed according to the expression;

V_hσ

,z=min_kR_hk+(1−

σ

_k){circumflex over (b)}_kVσ

+(1−

σ

_k)e_k,z 

 

(19)

where k is one of the plurality of devices;

h is the selected one of the plurality of devices;

R_hk is the transfer cost for device k;

{circumflex over (b)}_k is the cost of transitioning device k from a first mode to a second mode, the second mode consuming more power than the first mode;

σ

is a control state vector of the multi-device system, each k-th component indicating a state for device k, where a value of 0 corresponds to the first mode and 1 corresponds to the second mode;

z is a demand state of the multi-device system;

σ

, z is a state of the multi-device system;

e_k is a vector of Os for each component except the k-th component, which is 1; and

V is the second cost function; and

b) the second cost function in an optimal regime is computed according to the expression;

15. The method according to claim 14, wherein the time-out for a device is based on an estimation of demand for the device and transfers to the device.

16. The method according to claim 14, wherein the minimization of the second cost function includes:

reducing the optimization of the second cost function to a bounded sequence of one dimensional optimizations.

17. The method according to claim 14, wherein the minimization of the first cost function and the second cost function is performed at least partially in a function space.

18. A computer program product comprising a non-transitory recording medium wherein, when executed by a computer, performs the method of claim 14.

19. The method according to claim 14, wherein the expected energy consumption is the combined energy consumption expected of all of the plurality of devices.

20. A printing system comprising:

a plurality of print devices; and

,

a control system for reducing energy consumption, said control system comprising;

at least one processor programmed to;

receive a print job to be executed;

receive a print job ticket submitted by a user, the print job ticket submitted including a selection of one of the plurality of print devices for executing the print job and a transfer cost for transferring the print job from the selected print device to each of the plurality of print devices;

determine a print device from the plurality of print devices to execute the print job through optimization of a first cost function, the first cost function based on the print device selection, the received transfer costs, and power consumption costs of transitioning devices of the plurality of devices between different energy consumption modes;

assign the print job to the determined print device;

determine a globally optimized time-out for each of the plurality of print devices through optimization of a second cost function, wherein the time-out for each print device is the time for which the device remains in a first mode, after a job is completed, before moving to a second mode, which consumes less energy, in the absence of the arrival of another print job, the second cost function being based on an expected energy consumption by the printing system, the expected energy consumption being the combined energy consumption expected of all of the plurality of devices; and

,

provide the print devices with the determined time-outs; and

wherein at least one of the determining of the print device and the determining of the time-outs includes;

modeling a control problem as a Markov Decision Process (MDP), the MDP including the first cost function and the second cost function and wherein at least one of;

a) the first cost function in an optimal regime is computed according to the expression;

V_hσ

,z=min_kR_hk+(1−

σ

_k){circumflex over (b)}_kVσ

+(1−

σ

_k)e_k,z 

 

(19)

where k is one of the plurality of devices;

h is the selected one of the plurality of devices;

R_hk is the transfer cost for device k;

{circumflex over (b)}_k is the cost of transitioning device k from a first mode to a second mode, the second mode consuming more power than the first mode;

σ

is a control state vector of the multi-device system, each k-th component indicating a state for device k, where a value of 0 corresponds to the first mode and 1 corresponds to the second mode;

z is a demand state of the multi-device system;

σ

, z is a state of the multi-device system;

e_k is a vector of Os for each component except the k-th component, which is 1; and

V is the second cost function; and

b) the second cost function in an optimal regime is computed according to the expression;