This application is related to U.S. patent application Ser. Nos. 11/779,464; 11/779,512; 11/779,392; 11/779,418; 11/779,437; 11/779,454; and 10/946,756 filed Sep. 22, 2004.
The disclosed embodiments relate generally to a method and system for scheduling jobs in a manufacturing or production environment.
Manufacturing and production processes produce results by receiving sets of instructions and materials required to create or modify an item, such as a document, a vehicle, a computing device or another item. Often, the processes must permit some customization or alteration of individual items based on customer desires. For example, although an automobile production line may be configured to produce a particular make and model of car, the individual cars produced may have different specifications, such as leather or cloth seating, standard or premium wheels, exterior paint color and other specifications of type. As another example, document production environments, such as print shops, convert printing orders, such as print jobs, into finished printed material. A print shop may process print jobs using resources such as printers, cutters, collators and other similar equipment. Typically, resources in print shops are organized such that when a print job arrives from a customer at a particular print shop, the print job can be processed by performing one or more production functions.
Scheduling architectures that organize jobs arriving in a production process and route the jobs to autonomous cells are known in the art and are described in, for example, U.S. Pat. No. 7,051,328 to Rai et al. and U.S. Pat. No. 7,065,567 to Squires et al., the disclosures of which are incorporated by reference in their entirety.
Production environments can receive high volume jobs. In addition, there can be significant variability associated with the jobs due to multiple types of setup characteristics associated with each job. As such, the known scheduling architecture may be inefficient in processing high volume, highly variable jobs.
Variation in these production requirements from job to job can cause significant processing delays even when resources have been allocated to balance the job flow. For example, jobs can have a number of different setup characteristics, and each setup characteristic may correspond to several different characteristic types. Significant setup delays can arise in processing jobs with variable setup characteristics in a production environment. Setup time can be particularly acute in production environments where substantial interruption in operation is unacceptable, such as environments that utilize continuous feed or processing equipment. Setup delays can significantly impact throughput.
Before the present methods are described, it is to be understood that this invention is not limited to the particular systems, methodologies or protocols described, as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present disclosure which will be limited only by the appended claims.
It must be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to a “job” is a reference to one or more jobs and equivalents thereof known to those skilled in the art, and so forth. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. As used herein, the term “comprising” means “including, but not limited to.”
In an embodiment, a system of scheduling a plurality of jobs in a production environment may include a plurality of resources and a computer-readable storage medium comprising one or more programming instructions for performing a method of processing a plurality of jobs in a production environment. The method may include receiving a plurality of jobs and at least one setup characteristic corresponding to each job. Each job may have a corresponding job size. The method may also include determining, for each job, whether the corresponding job size exceeds a job size threshold, grouping each job having a job size that exceeds the job size threshold into a large job subgroup, grouping each job having a job size that does not exceed the job size threshold into a small job subgroup and routing the small job subgroup to a small job autonomous cell that includes one or more resources for processing the small job subgroup. The large job subgroup may be classified as a high setup subgroup or a low setup subgroup based on the setup characteristics corresponding to each job in the large job subgroup. The large job subgroup may be routed to a large job autonomous cell. If the large job subgroup is a high setup subgroup, the large job autonomous cell may include one or more first resources for processing the large job subgroup. If the large job subgroup is a low setup subgroup, the large job autonomous cell may include one or more second resources for processing the large job subgroup.
In an embodiment, a computer-implemented method of scheduling a plurality of jobs in a document production environment may include receiving a plurality of jobs and at least one setup characteristic corresponding to each job. Each job may have a corresponding job size. The method may also include determining, for each job, whether the corresponding job size exceeds a job size threshold, grouping each job having a job size that exceeds the job size threshold into a large job subgroup, grouping each job having a job size that does not exceed the job size threshold into a small job subgroup and routing the small job subgroup to a small job autonomous cell that includes one or more resources for processing the small job subgroup. The large job subgroup may be classified as a high setup subgroup or a low setup subgroup based on the setup characteristics corresponding to each job in the large job subgroup. The large job subgroup may be routed to a large job autonomous cell. If the large job subgroup is a high setup subgroup, the large job autonomous cell may include one or more first resources for processing the large job subgroup. If the large job subgroup is a low setup subgroup, the large job autonomous cell may include one or more second resources for processing the large job subgroup.
For purposes of the discussion below, a “production environment” or “production process” refers to an entity having multiple items of equipment to manufacture and/or process items that may be customized based on customer requirements. For example a vehicle production environment may exist in an automobile assembly plant, where different areas exist to assemble and/or finish portions of the automobile such as the engine, trim, drive train and other parts. A document production environment includes document production resources, such as printers, cutters, collators and the like. A chemical, pharmaceutical or other process industry production environment may include production resources such as chemical processing units, vessels, heating equipment, mixing equipment and the like. A production environment may be a freestanding entity, including one or more production-related devices, or it may be part of a corporation or other entity. Additionally, the production environment may communicate with one or more servers by way of a local area network or a wide area network, such as the Internet or the World Wide Web.
A “job” refers to a logical unit of work that is to be completed for a customer. A job may include one or more jobs to build, assemble or process a product. A production system may include a plurality of jobs.
Jobs may have different processing requirements. For example, incoming jobs may have variable job sizes, setup requirements, processing frequency and the like. An autonomous cell refers to a group of resources used to process jobs. An autonomous cell may include the resources needed to complete at least one job. For example, in a document production environment, if the job requires printing, cutting and collating, an autonomous cell for processing the job may include at least one printer, one cutter and one collator. In a chemical production environment, an autonomous cell may include production resources necessary to convert a plurality of raw material inputs into one or more complete chemical outputs.
In an embodiment, jobs may be partitioned into subgroups based on job size.
As illustrated in
In an embodiment, a subgroup may be categorized based on setup characteristics. A setup characteristic may include a feature of any step in the production process. For example, in a document production system, the printer setup may be dependent on the type of form used. Alternatively, the insertion operation setup may depend on one or more inserts associated with each job. As yet another example, in a chemical production environment, setup characteristics may be associated with cleaning and preparing production resources to process a next chemical product type. For example, a setup characteristic may include a time required to clean one production resource before it may be used to process another chemical product.
In an embodiment, each setup characteristic may be associated with one or more types. For example, a form type setup characteristic may be associated with three types of forms: form A, form B and form C. In an automobile production environment, setup characteristics may result from customer selections of trim design, exterior paint color, interior color, seating type, transmission type, engine size, audio equipment, security systems, remote start systems, other electronics options and/or other features. In a computer system production environment, setup characteristics may result from customer selections of hard drive capacity, random access memory capacity, processing speed, video or graphics cards, storage drives, operating systems, sound cards, installed software and/or other features.
Subgroups may be categorized based on the number of types associated with each setup characteristic. For example, in a vehicle production environment, a subgroup may be associated with two setup characteristics, such as trim type and exterior color. As illustrated by
In an alternate embodiment, subgroups may be categorized based on the average number of types associated with each setup characteristic over a specified interval. In addition, the average number of setup characteristics may be evaluated over multiple intervals. For example, a subgroup may utilize one trim type on day 1, three trim types on day 2 and two trim types on day 3, thus producing an average of two trim types per day.
In an embodiment, a threshold value may be determined for each setup characteristic. The threshold value may represent the number of types associated with each setup characteristic that may be necessary to optimize job flow. The threshold value may be determined using a simulation model, such as a model based on discrete event simulation, to simulate and optimize the workflow. A simulation-based approach may be used to determine an optimal number of types for each setup characteristic by using manual iteration until an improved solution is obtained. Alternatively, formal optimization techniques may be used. If formal optimization techniques are used, the threshold parameters may be specified as variables and a performance measure, such as the total number of late jobs, total production cost or the like, of the overall print shop may be used as an objective function to be optimized. Constraint functions may also be specified in addition to constraints on variables. Threshold parameters may then be determined via an optimization of the simulation model. Several techniques, such as mixed-integer programming, simulated annealing, genetic programs and the like can be used to perform the optimization that may include discrete and continuous decision variables.
In an embodiment, a subgroup may be categorized based on a comparison between the number of types associated with each setup characteristic and the threshold value for each setup characteristic. For example, if the threshold value associated with trim type is ‘2’ and the threshold value associated with exterior color type is ‘3’, a subgroup having two or fewer trim types and three or fewer exterior color types may be identified as a low setup subgroup. A low setup subgroup may include jobs that have low setup requirements when compared to the thresholds associated with the setup requirements. For example, a low setup subgroup may include jobs with similar setup requirements which may ease transitioning from one job to the next.
A subgroup having more than two trim types and/or more than three exterior color types may be identified as a high setup subgroup or the like. A high setup subgroup may include jobs that have high setup requirements when compared to the thresholds associated with the setup requirements. For example, a high setup subgroup may include several small to mid-sized jobs with substantially different setup requirements which may cause significant delays in transitioning from one job to the next.
In comparison, as illustrated by
In an alternate embodiment, a subgroup may be grouped based on different threshold conditions. For example, a subgroup may be identified as a low setup subgroup if the number of types associated with one setup characteristic is less than the threshold value associated with that setup characteristic. For example, a subgroup may be identified as a low setup subgroup if the number of form types associated with the subgroup is less than or equal to the threshold value associated with the form type characteristic. Referring to
In another embodiment, a subgroup may be identified according to a plurality of thresholds associated with the same setup characteristic. For example, a subgroup having a number of types less than a first threshold value, but more than a second threshold value may be grouped in an intermediate setup subgroup.
In an embodiment, a subgroup may be categorized based on multiple job attributes. For example, jobs may first be grouped into a large job subgroup or a small job subgroup based on job sizes.
If the threshold job size value is 1100, for example, the jobs 700 may be grouped into a large job subgroup, illustrated by
The large job subgroup illustrated in
Although this embodiment illustrates categorizing jobs first based on job size, then based on setup characteristics, additional and/or alternate methodologies may be used within the scope of this disclosure.
In an embodiment, jobs in a subgroup may be arranged prior to being processed. For example, jobs may be sequenced according to a first-in-first-out (“FIFO”) policy, an earliest due date (“EDD”) policy or the like.
A FIFO policy may arrange jobs based on the order in which they were received. For example, a subgroup may contain three jobs, J1-J3. If J2 is received first, J1 is received second and J3 is received third, the subgroup may be processed in the following order. J2, J1, J3.
An EDD policy may arrange jobs based on the order in which they are due. For example, a subgroup may contain three jobs, J1-J3. If J3 is due first, J1 is due second and J2 is due last, then the subgroup may be processed in the following order: J3, J1, J2.
In an embodiment, a subgroup may be routed to one or more autonomous cells using a least work-in-progress policy, a round robin policy, a random policy, a size interval task assignment with equal load (“SITA-E”) policy or the like.
A least work-in-progress policy may determine a volume of work within each autonomous cell and may route job sets to the autonomous cell with the smallest work volume. For example, as illustrated by
A round robin policy may route a subgroup to an autonomous cell in a particular order. For example, autonomous cells may receive subgroups sequentially or in a specified order. The round robin policy may route a subgroup to the autonomous cell which is next in the order. As illustrated by
A random policy may randomly route jobs to an autonomous cell. For example, referring to
A SITA-E policy may route subgroups to an autonomous cell tasked with processing job sets of similar sizes. For example, each autonomous cell may be assigned a separate range of job sizes so that the total load each autonomous cell receives is roughly the same. In an embodiment, a job size distribution that appears to have heavy-tail characteristics may be modeled using a bounded Pareto distribution such that:
Variable k may represent the smallest job size in the distribution, variable p may represent the largest job size in the distribution and a may represent the index of stability that may be determined through fitting the distribution. The job size distribution may then be divided into multiple segments where each segment may be represented as:
It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
Number | Name | Date | Kind |
---|---|---|---|
4821029 | Logan et al. | Apr 1989 | A |
5095369 | Ortiz et al. | Mar 1992 | A |
5287194 | Lobiondo | Feb 1994 | A |
5513126 | Harkins et al. | Apr 1996 | A |
5559933 | Boswell | Sep 1996 | A |
6223205 | Harchol-Balter et al. | Apr 2001 | B1 |
6509974 | Hansen | Jan 2003 | B1 |
6546364 | Smirnov et al. | Apr 2003 | B1 |
6573910 | Duke et al. | Jun 2003 | B1 |
6583852 | Baum et al. | Jun 2003 | B2 |
6631305 | Newmark | Oct 2003 | B2 |
6633821 | Jackson et al. | Oct 2003 | B2 |
6687018 | Leong et al. | Feb 2004 | B1 |
6762851 | Lynch et al. | Jul 2004 | B1 |
6763519 | McColl et al. | Jul 2004 | B1 |
6805502 | Rai et al. | Oct 2004 | B2 |
6925431 | Papaefstathiou | Aug 2005 | B1 |
6961732 | Hellemann et al. | Nov 2005 | B2 |
6970261 | Robles | Nov 2005 | B1 |
6993400 | Viassolo | Jan 2006 | B2 |
7016061 | Hewitt | Mar 2006 | B1 |
7051328 | Rai et al. | May 2006 | B2 |
7061636 | Ryan et al. | Jun 2006 | B2 |
7065567 | Squires et al. | Jun 2006 | B1 |
7079266 | Rai et al. | Jul 2006 | B1 |
7092922 | Meng et al. | Aug 2006 | B2 |
7092963 | Ryan et al. | Aug 2006 | B2 |
7099037 | Clark et al. | Aug 2006 | B2 |
7125179 | Rai et al. | Oct 2006 | B1 |
7148985 | Christodoulou et al. | Dec 2006 | B2 |
7152589 | Ekeroth et al. | Dec 2006 | B2 |
7161699 | Matoba | Jan 2007 | B2 |
7161705 | Klassen | Jan 2007 | B2 |
7174232 | Chua et al. | Feb 2007 | B2 |
7200505 | Shan | Apr 2007 | B2 |
7206087 | Ryan et al. | Apr 2007 | B2 |
7382484 | Matsukubo et al. | Jun 2008 | B2 |
7408658 | Twede | Aug 2008 | B2 |
7523048 | Dvorak | Apr 2009 | B1 |
7548335 | Lawrence et al. | Jun 2009 | B2 |
7562062 | Ladde et al. | Jul 2009 | B2 |
7567360 | Takahashi et al. | Jul 2009 | B2 |
7576874 | Farrell et al. | Aug 2009 | B2 |
7584116 | Kakouros et al. | Sep 2009 | B2 |
7590937 | Jacobus et al. | Sep 2009 | B2 |
7684066 | Shirai | Mar 2010 | B2 |
7689694 | Kato et al. | Mar 2010 | B2 |
7761336 | Blankenship et al. | Jul 2010 | B1 |
7872769 | Akashi et al. | Jan 2011 | B2 |
7949740 | Scrafford et al. | May 2011 | B2 |
8004702 | Noda | Aug 2011 | B2 |
8384927 | Harmon et al. | Feb 2013 | B2 |
20010055123 | Ryan et al. | Dec 2001 | A1 |
20020016803 | Ryan et al. | Feb 2002 | A1 |
20020054344 | Tateyama | May 2002 | A1 |
20020057455 | Gotoh et al. | May 2002 | A1 |
20020071134 | Jackson et al. | Jun 2002 | A1 |
20020129081 | Rai | Sep 2002 | A1 |
20020174093 | Casati et al. | Nov 2002 | A1 |
20020198794 | Williams et al. | Dec 2002 | A1 |
20030079160 | McGee et al. | Apr 2003 | A1 |
20030098991 | Laverty et al. | May 2003 | A1 |
20030105661 | Matsuzaki et al. | Jun 2003 | A1 |
20030121431 | Ohno | Jul 2003 | A1 |
20030149747 | Rai et al. | Aug 2003 | A1 |
20030200252 | Krum | Oct 2003 | A1 |
20030202204 | Terrill et al. | Oct 2003 | A1 |
20040130745 | Fabel et al. | Jul 2004 | A1 |
20040135838 | Owen et al. | Jul 2004 | A1 |
20040136025 | Moriyama et al. | Jul 2004 | A1 |
20040239992 | Kawai et al. | Dec 2004 | A1 |
20040267485 | Penov et al. | Dec 2004 | A1 |
20040268349 | Ramakrishnan et al. | Dec 2004 | A1 |
20050060650 | Ryan et al. | Mar 2005 | A1 |
20050065830 | Duke et al. | Mar 2005 | A1 |
20050068562 | Ferlitsch | Mar 2005 | A1 |
20050114829 | Robin et al. | May 2005 | A1 |
20050134886 | Farrell et al. | Jun 2005 | A1 |
20050151993 | Gartstein et al. | Jul 2005 | A1 |
20050154625 | Chua et al. | Jul 2005 | A1 |
20050275875 | Jennings, Jr. | Dec 2005 | A1 |
20060031585 | Nielsen et al. | Feb 2006 | A1 |
20060132512 | Walmsley et al. | Jun 2006 | A1 |
20060149755 | Marshall et al. | Jul 2006 | A1 |
20060224440 | Rai | Oct 2006 | A1 |
20060226980 | Rai et al. | Oct 2006 | A1 |
20070008580 | Tanaka | Jan 2007 | A1 |
20070019228 | Rai et al. | Jan 2007 | A1 |
20070070379 | Rai et al. | Mar 2007 | A1 |
20070078585 | Pomeroy et al. | Apr 2007 | A1 |
20070091355 | Rai | Apr 2007 | A1 |
20070092323 | Lin et al. | Apr 2007 | A1 |
20070124182 | Rai | May 2007 | A1 |
20070177191 | Eschbach et al. | Aug 2007 | A1 |
20070236724 | Rai et al. | Oct 2007 | A1 |
20070247657 | Zhang et al. | Oct 2007 | A1 |
20070247659 | Zhang et al. | Oct 2007 | A1 |
20070279675 | Quach et al. | Dec 2007 | A1 |
20070293981 | Rai | Dec 2007 | A1 |
20080013109 | Chen et al. | Jan 2008 | A1 |
20080201182 | Schneider et al. | Aug 2008 | A1 |
20080239368 | Ota | Oct 2008 | A1 |
20080256541 | Rai | Oct 2008 | A1 |
20090094094 | Rai et al. | Apr 2009 | A1 |
20090313061 | Rai et al. | Dec 2009 | A1 |
20090313063 | Rai | Dec 2009 | A1 |
20090327033 | Rai et al. | Dec 2009 | A1 |
Number | Date | Country |
---|---|---|
2503427 | Oct 2005 | CA |
1630663 | Mar 2006 | EP |
1705556 | Sep 2006 | EP |
11282909 | Oct 1999 | JP |
2003058340 | Feb 2003 | JP |
2005011066 | Jan 2005 | JP |
2005250823 | Sep 2005 | JP |
Entry |
---|
Kallrath Josef, “Planning nd scheduling in the process industry,” OR Spectrum, Springer-Verlag (2002), 24:219-250. |
Burkard Rainer E., et al., “A process scheduling problem arising from chemical production planning,” Optimization methods and software, vol. 10 issue 2, 1998 pp. 175-196. |
Mestha, Lalit K., et al. “Control elements in production printing and publishing systems: DocuColor iGen3.” Decision and Control, 2003. Proceedings. 42nd IEEE Conference on. vol. 4. IEEE, 2003. |
Potts, Chris N., and Mikhail Y. Kovalyov. “Scheduling with batching: a review.” European Journal of Operational Research 120.2 (2000): 228-249. |
Crovella, Mark E., Mor Harchol-Balter, and Cristina D. Murta. “Task assignment in a distributed system (extended abstract): improving performance by unbalancing load.” ACM SIGMETRICS Performance Evaluation Review. vol. 26. No. 1. ACM, 1998. |
Schroeder, Bianca, and Mor Harchol-Balter. “Evaluation of task assignment policies for supercomputing servers: The case for load unbalancing and fairness.” Cluster Computing 7.2 (2004): 151-161. |
Harchol-Balter, “On Choosing a Task Assignment Polley for a Distributed Server System”, IEEE Journal of Parallel and Distributed Computing, 1999, pp. 204-228. |
Dueck, et al., “Threshold Accepting: A General Purpose Optimization Algorithm Appearing Superior to Simulated Annealing”, Journal of Computational Physics vol. 90, Issue 1, Sep. 1990, pp. 161-175, Academic Press, Inc. |
Rai, et al., “A Lean Document Production Controller for Printshop Management”, Proceedings of the 42nd IEEE Conference on Decision and Control, Maui, Hawaii, Dec. 2003. |
Zheng et al., “Finding Optimal (s,S) Policies Is About as Simple as Evaluating a Single Policy”, Operations Research, vol. 39, No. 4, (Jul.-Aug. 1991), pp. 654-665. |
Bo Hu, “An Application of Inventory Models in Printing Industry”, Ph.D. Candidate in Operations Management, The Simon School of Business, University of Rochester, Jul. 2007. |
Veinott, Jr., et al., “Computing Optimal (s,S) Inventory Policies”, Management Science, vol. 11, No. 5, Series A., Sciences, Mar. 1965, pp. 525-552. |
Simchi Levi, et al. “Designing & Managing The Supply Chain: Concepts, Strategies, and Cases”, Second Edition, 2000, McGraw-Hill Higher Education, New York, New York. |
Cleveland et al., “STL: A Seasonal-Trend Decomposition Procedure Based on Loess”, Journal of Official Statistics, vol. 16, No. 1, 1990, pp. 3-33, Sweden. |
Veinott, Jr., “Optimal Policy in a Dynamic, Single Product, Nonstationary Inventory Model with Several Demand Classes”, Mar. 16, 1965, Operations Research, vol. 13, No. 5, Sep.-Oct. 1965, pp. 761-778. |
Faraway, “Extending the Linear Model with R: Generalized Linear, Mixed Effects and Nonparametric Regression Models” 2006, Chapman & Hall/CRC, Boca Raton, Florida. |
Creo, “UpFront White Paper”, www.creo.com, May 2003, 14 pages. |
Mason, Dennis E., “Workflow: Defining Print's Future”, www.printandgraphicsmag.com/edit—pages/0803/lead.html, Apr. 7, 2005, 3 pages. |
Lesh, et al., “Improving Big Plans”, Computer Science Department, University of Rochester, 8 pages. |
Wellman, Michael P., “Fundamental Concepts of Qualitative Probabilistic Networks”, WRDC/TXI, 58 pages, Wright-Patterson AFB, OH. |
Mohammed, et al., “Planmine: Sequence Mining for Plan Failures”, Computer Science Department, University of Rochester, Rochester, NY, 5 pages. |
Wil Van Der Aist et al., “Workflow Mining: Discovering Process Models from Event Logs”, IEEE Transactions on Knowledge and Data Engineering, vol. 16, No. 9, Sep. 2004, 14 pages. |
Mohammed, J. Zaki, et al., “PlanMine: Predicting Plan Failures Using Sequence Mining”, The University of Rochester Computer Science Department Technical Report 671, Jul. 1998, 22 pages. |
Nebel, et al., “Plan Reuse versus Plan Generation: A Theoretical and Empirical Analysis”, to appear in Artificial Intelligence (Special Issue on Planning and Scheduling), Mar. 9, 1995, 21 pages. |
Marco, Dorigo, et al., “The Ant System: Optimization by a Colony of cooperating agents” IEEE Transacations of Systems, Man and Cybernetics—Part B, vol. 26, No. 1, 1996, pp. 1-26. |
Doerner, Karl, et al., “Ant Colony Optimization in Multiobjective Portfolio Selection”, 4th Metaheuristics International Conference, Porto, Portugal, Jul. 16-20, 2001, pp. 243-248. |
Number | Date | Country | |
---|---|---|---|
20090021775 A1 | Jan 2009 | US |