Production planning and scheduling

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Production planning and scheduling

  1. 1. An Innovative Real Time Production Management System A white paperAbstractScheduling is indeed a major issue in all manufacturing and project execution facilities world over. It is alsorecognized that if scheduling is efficient and automated huge benefits could result as existing resource usage canbe maximized allowing dramatic increase in number of orders processed at the same time substantially reducingcost of production while ensuring reliability in delivery on the committed date. No wonder scheduling is a hotresearch topic and the market is flooded with scheduling systems of sorts. Still a truly efficient and automaticscheduling system remains an elusive dream.This white paper lists the six important reasons why a scheduling system fails in real-life situations. It thendescribes how a new scheduling system called Talika PMS satisfies all the six critical requirements in detail with realdata supporting the claims from its first major installation. Visit www.etalika.in for more information and free download1 Introduction Before we elucidate more on the system features we would like to re-emphasis importance of schedulingDay-to-day scheduling of any manufacturing facility in any manufacturing facility and why currentis recognized to be the most important problem to solutions fail to address the problem correctly.be solved. [1] D. Ouelhadj and S. Petrovic recent[Oct 2008] study reveals that solutions based on 2 Importance of schedulingcreation of a static schedule are impractical in real-life situations and discusses several dynamic The only real differentiators to compete inscheduling approaches only to conclude that more established products and services market are Costwork is still needed in this field of research. and Reliable delivery. Quality of product / service is mostly considered a pre-condition to be in businessWe wish to present here a complete dynamic real- rather than a differentiator. Both cost and reliabletime micro level scheduling system that is proven to delivery of product / service are directly impacted bywork in the most complex manufacturing facilities. It scheduling.is a fully scalable, decentralized, multi-location anduser configurable system to suit any manufacturing / 2.1 Scheduling and cost of productionproject environment. The core scheduling is fullyautomatic and guarantees that all currently allotted It is almost axiomatic to state that a major portion oftasks in real-time can be executed with a complete cost of production (even exceeding 70% - 80% inand detailed schedule prediction of all activities for made-to-order industries) is expended inall orders in-hand. The system automatically coordinating and managing production activities vis-reschedules in response to real-time events as à-vis the actual cost of value-addition involved.notified by operators’ handling current tasks on theshop floor, with an objective to maximize resource Most real life manufacturing involves execution ofutilization while minimizing job cycle time. It offers several individual activities in a complex order tofull micro-level future schedule visibility of all create any saleable final product or service. Therunning jobs to predict when each would be over starting point thus is in breaking down an ordergiven the current load as of NOW. The cycle of requirement into elemental activities that must beallotting tasks, seeking task-wise feedback on completed in order to accomplish the final product /allotments made from operators’ on shop floor, and service deliverable: ranging from getting inputs orre-predicting its impact in subsequent reschedule raw material until final packing and dispatch. Unlesshappen every minute 24x7. this detailing is not done, actual value addition cannot begin. Once it is known “How” the order can be fulfilled the most difficult job of scheduling Page 1 of 13 © 2013, Laxman C Marathe
  2. 2. individual activities of orders begin. It primarily seldom match reality owing to unexpectedtranslates in deciding what activity must be done, disruptions [3] & [5].where it should be done (that is using what limitedresources) and when. One can refer to them as the So, any scheduling system that fails to respond to3W’s. Most expensive and competent personnel in changing situation on ground by failing to rescheduleany manufacturing or project execution facility are and redraw its prediction (Gantt chart) is a misfit inengaged fully in the process of managing production real life making purported schedule optimality andthat involves, breaking down order execution, efficiency claims hypothetical.estimating its cost, time and wastages, decidingwhat activities to do now and next, taking feedback 3.2 No feedback mechanismon progress made, follow-up and expediting to meetdeadlines. The whole exercise is repeated all over A scheduling system can only be responsive to whatagain by rescheduling to predict and monitor is happening on the shop floor if a feedbackexpected completion dates for all orders in hand. mechanism exists. This feedback mechanism should be both real-time and automatic. Peter Cowling andAdd to this already complex situation, the burden of Marcus Johansson [2] argue in a well researchedestimating when new orders can be delivered given paper that “in many production processes real timethe existing load of orders already in-hand. All this is information may be obtained from process controlnow possible to be completely automated resulting computers and other monitoring systems, but mostin a substantial reduction in the cost of production. existing scheduling models are unable to use this information to effectively influence scheduling2.2 Scheduling & reliability decisions in real time”. This is a major disconnect making the schedule infeasible as it is soon out ofScheduling decisions taken now directly impact synchronization with reality.expected completion times of all orders in-hand. Inreal-life situations one has to deal with several We have recognized that the only authentic real-orders, each with its own set of individual time source of feedback information from the shopinterdependent activities requiring a certain profile floor is the personnel (Operators’) in charge ofof resources that are both shared and limited. It is performing individual activities. However, eachwell impossible, even in small setups, to manually operator can only give feedback on what each onefigure-out impact of real-time decisions on predicted does and that too ideally limited to the current taskcompletion dates. in-hand. We achieve a seamless feedback mechanism to the scheduling engine by allocatingHonoring delivery on committed date is more elemental executable tasks in real-time to individualimportant than how fast one turns around an order Operators, and seeking task-specific feedback forin a manufacturing facility. It is only possible to do each such allotted task. The process of taskso, if one is in a position to predict impact of all allotment, progress feedback and subsequentscheduling decisions taken now on all orders in-hand reschedule to decide what to do next happens 24x7in real time as an on-going process. automatically.3 Why conventional scheduling systems fail in the 3.3 Schedule not actionablereal world? The decision to execute an elemental task or activity3.1 Static scheduling of an order requires one to take into account several aspects; availability of inputs, availability ofScheduling is a widely misunderstood term. Many resources and technical feasibility of performing thebelieve plotting activities to be performed on task. Most scheduling systems usually fail on thisdifferent resources on a time scale (Gantt chart) count. Proposed activities are either not actionablemake a schedule. Actually a Gantt chart is just a or represent a group of activities leaving the decisionsnap shot of what is likely to happen in the future of what exactly to do now to the operators. In ordergiven the situation NOW. As one progresses in time to circumvent this problem, many systems offer athis representation will change because predictions “drag & drop” facility to correct or manipulate proposed schedule before it is released. As [4] P. Page 2 of 13 © 2013, Laxman C Marathe
  3. 3. Velaga asserts, presence of a “drag & drop” facility unaltered any amendment to future task listing in noindicate an inherent weakness of the scheduling way adds to nervousness. On the contrary, impactlogic. on completion dates of all jobs in hand must be known immediately not when the next frozen3.4 Manufacturing facilities are on-going concerns schedule is created.Getting new orders and completing existing orders is We propose a true scheduling system called Talikaa continual process in real facilities. Existing Production Management System (PMS) that satisfiescommitments cannot generally be disturbed because all the above primary requirements.of new orders. Situations can become more complexas orders could be cancelled or amended. Any 4 Overview of Talika PMSscheduling solution that considers a static order loadis therefore impractical. The system has a distributed architecture as indicated in Figure-1. At the center is the real-time3.5 Working in shifts scheduling engine working round-the-clock and is the live heart of the system. Several different typesMany manufacturing facilities work round the clock of consoles interact with the scheduling engine usingin shifts manned by a different set of personnel. a proprietary protocol that is robust andScheduling decisions impact across shifts and the asynchronous making the entire process ofbiggest challenge becomes information handover communication absolutely safe.between shifts. The only remedy is in having thescheduling systems work 24x7 continuously. There are several different types of consoles each designed to perform a specific function on the shop3.6 Stability versus responsiveness floor. Consoles work in a standalone mode but can also communicate with the scheduling engine, ifMost scheduling systems provide a stable schedule connected, making the entire distributed system livefrozen for a period (usually a few days) and expects and reliable. Exhibit–1 at the end detailsit to hold well unless disruptions occur, which functionality of each Console shown in Figure-1 andinevitably do occur. It is reasoned that having a explains how the automatic scheduling engine drivescontinually changing schedule results in shop floor other peripheral or support activities. Most ERPnervousness. Shop floor nervousness is a myth systems only handle the peripheral activities sanspropagated to hide inability of doing a quick the driving scheduling engine at its heart, making itreschedule. Operators’ are only concerned with the more of a fancy carcass disconnected from the shoptask in-hand. As long as the current task remains floor. Page 3 of 13 © 2013, Laxman C Marathe
  4. 4. Figure-1: Macro system schema5 How the system works One can also create part CT diagrams for common work flows in the factory and saveFigure-2 gives an at-a-glance view of how the them as sub-assemblies. Sub-assemblies areentire system works. building blocks one may use to quickly create a new complex job definition.5.1 Starting point Jobs are stored as proprietary files with aJob Study Wizard (JSW) is the starting point. As default “*.tlk” extension to any media. One canalready explained each sales person or save, share and reuse stored jobs over and overconcerned agency can have a JSW of their own. again just like a text file.Potential enquiries can be quickly converted to adetailed job definition depicted as an easy to 5.2 Scheduling a jobunderstand component task (CT) diagram. CTdiagram actually represents the micro level It is not necessary all defined jobs be actuallyactivity work flow for creating one-something of scheduled. Jobs could be defined when weany value-added service or product. It is more receive an enquiry to estimate its cost andlike a recipe. One can always scale it up or down assess delivery date, but we only need toto match extent of final output required keeping schedule the order when it matures. Whenthe CT diagram (recipe) unchanged. It is also scheduled, orders flow over to the schedulingpossible to create, as a one-time exercise, a engine and the process of executing itsbank of most standard CT diagrams (standard constituent tasks begin.orders) used in the facility. So, defining neworders may simply translate into picking up an 5.3 Role of scheduling engine and shop floorappropriate or nearly matching already defined interface: Work Center Console (WCC)CT diagram and making minor adjustments to it. Scheduling engine works 24x7 and proactively controls all factory work centers at a micro level. Page 4 of 13 © 2013, Laxman C Marathe
  5. 5. It decides what tasks of which orders can and to the scheduling engine to be taken cognizanceshould be actually allotted for execution to the of during the next reschedule that happensshop floor. Complete information of currently every minute. This cycle of allotting tasks,allotted tasks flows to the concerned WCC in getting progress and completion notificationreal-time. Operators’ acknowledge allotted feedback, and subsequent fresh allotment ontasks to start execution and notify interim each work center on the shop floor goes onmilestones achieved, until the allotted task is without end.not over. All notifications flow back in real-time Figure-2: Working principle at-a-glance6 Working logic of scheduling engineScheduling engine comprises of a set of complex the JSW itself. Only on confirmation, validdaemons working round-the-clock. Like a orders are communicated to the schedulinghuman scheduler does, it always decides what engine. During order definition stage itself a lottasks to execute now. The entire optimization of detailing about the job is done including de-principle could be summed in one line as “if selection of technically non-feasible worksomething (read a task) can be done and it centers to execute specific tasks of the job.should be done then it will be done”. The above User can also specify several guidelines for therule automatically guarantees that resource scheduling engine to follow while executing theutilization is maximized while simultaneously order called “execution preferences”.reducing job cycle time. Scheduling engine uses its own intelligence while implementing user specified guidelinesAn order is first broken-down to its elemental but ensures they are honored whenevertasks in form of a CT diagram during definition in possible. Execution preferences are not rigid; Page 5 of 13 © 2013, Laxman C Marathe
  6. 6. they can be changed even at run-time after a all tasks in an order. Table-1 below lists thejob is scheduled. Execution preferences could execution preferences and explains what eachbe different for each task. However, user can means and how the scheduling engine usesspecify them just once with applicability them while making allotment decisions.controlled across parts or group of tasks or forTable-1: Execution Preferences and what they mean Execution preference What it means Scheduling engine usage If WIP is not on the critical Attempt to minimize work-in- chain and has enough time left progress (WIP) from being to be produced and used then WIP control created too much in advance its creation is deferred thereby and thus remain unused. minimizing WIP build-up on the shop floor. Tasks are allotted first by order priority and then by the future User desires to change task Control of task burden on the task within an execution order, if necessary, at execution order order. However, user may run-time. change this natural order of execution at run time. Scheduler tries to honors user preference with switchover savings, if any, considered. In If one has a choice of work case the first preferred work Work center choice centers to perform a task then center is unavailable it tries to which one to choose? allot the task on the second preferred work center and so on. Ensuring a particular task is Always tries to execute the said Locking Option only executed within a user task within the specified period, specified period. as far as possible. If the task is on the critical chain Breaking up a task to run or its execution cannot be concurrently on more than one deferred any further scheduling Auto-breaking option work center with an intention engine will try to optimize and to reduce task execution time. select the most appropriate breaking option possible. Stop and resume task execution after a holiday, recess period. Scheduler wisely decides to Spanning Option Commonly referred to as a non- span or not to span depending scheduling time zone (NSTZ) in on the current situation. the system. Page 6 of 13 © 2013, Laxman C Marathe
  7. 7. Execution preference What it means Scheduling engine usage It may not be necessary to wait to start the next value-adding Scheduler tries to begin the task that uses or consumes next value adding task even what is produced by the current before the earlier one feeding task until the current task is not into the next one is not yetMCI option over. One can overlap in time over. Time to initiate the next both tasks in order to expedite task can be user decided or left the order. We can say the to the scheduling engine to preceding task gives a mid- figure out. course intimation (MCI) to the next task to begin. User may want some tasks (orders) to be executed only Scheduler ensures the task is when there is free timeInterleaving option executed whenever there is available. Contrast this with nothing urgent to be done. auto-breaking where the objective was to expedite. Especially in long running tasks interim milestone reached MCF is used constructively to feedback may be necessary to adjudge the expectedMCF Option re-adjust expected task completion time for long completion time. We call it a running tasks. mid-course feedback (MCF). NSTZ is an acronym for non- scheduling time zones. Periods when the scheduling engine will not schedule (allot) a fresh task. Scheduling engine takes However, an already running appropriate decision to cut into task can either by design (or NSTZ whenever necessary.NSTZ cut-in option because it is delayed) cut-into Working during NSTZ is an an impending NSTZ. System additional cost and calculated supports five categories of NSTZ accordingly. with varying importance and user can define how much a particular task can actually cut into each of them. Page 7 of 13 © 2013, Laxman C Marathe
  8. 8. Execution preference What it means Scheduling engine usage It is possible for user to specify that in an order if some task A is executed on a particular work center then preferably task B too should be the next one You can guess concept of followed by task C and so on. cascading is different from Valid reason could be controlling task execution substantial saving in cost and order. The former is applicable Task line-up time if done so. We call it task within an order whereas the cascading. This again could be later could be across orders and a preferential cascading or a typically is a run-time user forced cascading when user intervention. insists that the scheduling engine waits a pre-determined period for the next cascaded task to mature for execution.In addition to above user specified execution up unless filled-up to some predefined minimumpreferences, the scheduling engine takes into capacity.consideration several other aspects as well anddoes its own run-time adjustments as listed 6.3 Considering time for material movementbelow. and normalization6.1 Work center capacity In real facilities it takes a while for work-in- progress to be moved from the place it isChecking if it is possible for a given task to be created to where it is needed for further value-executed on a work center must be done before addition. This time too must be taken intoeach allotment. Our system allows user to account before deciding fresh allotment. Bothdefine multi-part work centers that could either fixed and variable types of material movementwork as a whole or in parts enabling one to are considered and require separate notificationexecute a variety of tasks each requiring it own from a special console called Materialpart capacity profile. Movement Console (MMC) given to the person responsible for material movement.6.2 Activating work center Additionally, certain WIP may require time toResources and work centers are conventionally set, dry, solidify, etc. We call it time tothought as synonyms, but in our system a normalize the WIP produced before furtherresource has a very special meaning: a work value-addition on it can begin.center to become active requires resources.What resources are required to activate a work 6.4 Deciding need for expediting or skippingcenter is user defined. Therefore, if a work task allotmentcenter is currently not active it is necessary tocheck for resource availability. Task allotment Breaking a task over more than one workcan only happen if it is possible to activate a centers for concurrent execution is onlywork center. This check is done automatically advantageous if the task in question has reachedby the scheduling engine. a critical stage. In our language, has sufficiently exhausted the available leeway. SchedulerActivating work centers could also be dependent reckons how much the current leeway availableon capacity usage. A typical case could be an is before taking such decisions. Likewise, ifindustrial oven that is uneconomical to be fired- sufficient leeway is available and if the user desires task allotment may be skipped allowing Page 8 of 13 © 2013, Laxman C Marathe
  9. 9. other urgent tasks to be handled in the while raising an alarm for human intervention tomeanwhile. amend order workflow.Further, if sufficient time is not available to 6.9 Monitor completion is within committedcomplete a task as one has an impending NSTZ dateor locked task then the scheduling engine couldeither span the task, if possible, or decide to skip Generally one must keep some safety bufferallotment until later. between when actually an order will be completed and the date of delivery committed6.5 Deselecting inappropriate work center to the customer. On each reschedule, expected completion time for all orders are re-calculated.At run-time work centers that were originally However, if for some reason order completionthought appropriate to execute a task may crosses the cut-off date an alarm is raised by thebecome inappropriate as they waste more than scheduling engine.the reported good count of inputs actuallyavailable now. Similarly, in a multi-plant facility 6.10 Monitoring task execution (duration,if certain WIP is created in one plant and the wastage, cost etc.)next value-adding work center too is available inthe same plant but not currently free then the Expected duration, cost, wastage, time for thescheduling engine may decide to wait for it to output from a task to become usable forbecome free rather than send WIP to another subsequent value-addition (normalization time)plant’s work center if doing so is advantageous. and capacity the task may partake of each work center it can be executed on, are all calculated6.6 Deciding to hasten-up task execution during job definition stage itself in the JSW. User can define complex formulae and lookupNo matter how complex a rule one may use to tables using attribute values specific to eachanticipate task’s total duration it is still an task to arrive at these figures. However, theestimate. When situation demands one may scheduling engine also captures the actualslightly expedite task execution to finish it faster values in each case. Doing so not only allowsthan expected. It is a done thing in practice and one to control deviation task-wise at run-timethe scheduling engine too, if necessary, does the but enables periodic revision of estimation rulessame, of course within user permitted limits. in order to match them to reality as closely as possible.6.7 Decision to re-purpose inputs For example, if any task actual execution timeIdentical inputs could be processed by different exceeds its estimated duration it turn black ontasks to produce something different. the live Gantt chart allowing concernedAssignment of specific task inputs is rather supervisors to only focus on late tasks. Severalnotional and one can, if need be, re-purpose useful reports too can be generated highlightinginputs to expedite those tasks whose other exceptions. Actual vis-à-vis estimated data caninputs are deemed available. Human schedulers also be used to tailor a micro-level incentiveoften take such decisions and so does the scheme as resource capacity is translated inscheduling engine provided user allows (or time terms and thus easier to assess anddefines) such a swapping as possible. monitor.6.8 Decision to freeze part or whole order 6.11 Procurement and maintenance too are considered tasksIn case of any reported shortfall in WIP count forany reason it makes sense to temporarily halt We consider procurement of customer inputsorder execution, make good the shortfall and and raw material too as tasks performed bythen resume executing order again. Humans do customer interaction personnel or buyers. Anytake such decisions and so does the scheduling deviation in expected arrivals of inputs has aengine. It decides to suspend order execution bearing on the overall schedule. Likewise, Page 9 of 13 © 2013, Laxman C Marathe
  10. 10. maintenance activities also keep the work 7 Vital statistics from the first successfulcenters busy and affect the schedule and thus installationare treated as tasks. The entire system is now mature and rigorously6.12 Actual task execution may not always be tested to exacting conditions in its first full-successful fledged installation at a medium sized commercial print setup in India. It has beenEvery allotted task may not be completed working for more than 3 years now giving us thesuccessfully. We have the following options confidence to make it available for the benefitavailable with the Operator for an allotted task. of the world at large.Operator can roll back an allotted task with arequest to reassign it later. In case, Operator The system is user configurable and starts byhas already started working on the task it could defining the manufacturing facility in detail.still be re-allotted: a way of telling the They include identifying:scheduling engine that it is not possible tocomplete the task now though it can be 7.1 Work centerscompleted later by me or by someone else.Operators’ can pause and resume working on a Listing of individual work centers of the factory,task. In the worst case, Operators’ can also classified by departments, and if a multi-plantdeclare a task as terminated meaning it is no (location) facility, then by plants. The firstmore possible to complete the task as inputs are installation is a multi-plant facility. Table-2 giveseither damaged or destroyed - an error details of the work centers and theircondition requiring human intervention to make distribution.good the shortfall. All the above impact theschedule and are considered by the scheduling Table-2: First installation work center detailsengine. Number of individual work 419 centerThen there are several more activitiesperformed by the scheduling engine like – Number of departments 47• Reassessing what is completed until now Number of plants / locations 5• How much more time existing tasks would require 7.2 Tasks and what they produce• The actual time, wastages and costs (including overtime cost) incurred until now Tasks get executed on work centers. Tasks and so on. produces some things recognized as “component” and may also require some thingsIt is very easy to guess, a lot of thinking happens to add value to, again a “component”. The tasksto ensure that each allotted task can indeed be and the components it produces actually makeexecuted on the shop floor and every up the CT diagram. User must define whateventuality, even after task allotment, is taken elemental value-adding tasks can be performedcognizance of. Technically the scheduling in the facility and what generic componentsengine can run autonomously with inbuilt they produce. They are but few in type - whatcapability to raise an alarm for human changes from order-to-order is are theintervention only when situation so warrants – a attributes of generic tasks and components like,precondition for realizing a true computer extent to be value-added, cost, wastage,controlled manufacturing facility. duration, etc. Table-3 details the number of generic tasks and components defined in the first typical installation. Page 10 of 13 © 2013, Laxman C Marathe
  11. 11. Table-3: First installation task & component scenario, if time to reschedule exceeds 60details seconds the system automatically, for such Number of generic tasks 27 instances, chooses to skip a reschedule to align with the next minute. Number of generic 71 components 8 Conclusion thActual system performance as on 19 April Talika PMS is in its infancy. It is just born. Not2013. many are even aware that such an inexpensive, easy to use, self-configurable, off-the-shelfHistory: The first installation is in its fourth product exist that holds the promise ofsuccessful year with the average mean time positioning any manufacturing facility leaguesbetween system failure now exceeding 6 apart from its competitors in terms of cost ofmonths, which in the beginning was around 6 production and reliability of service offered. It isminutes. That shows how reliable the system just a matter of time before someone makes anow is. beginning forcing others to adopt similar systems just to remain in business.Each time a job is scheduled it is given a runningserial number. It started from ‘1’ and now reads You can know more about Talika PMS by30900. With 706 currently active jobs, it means visiting www.etalika.in and also download a30194 jobs were successfully executed by or via free full demo version for evaluation.the system with each job having about 70elemental tasks on an average.How fast it works: The scheduling Engine workson Dell T310 Power edge server. It has 706currently active jobs with 49466 elemental tasksto schedule individually with all the complexityof decision making already described. Table-4gives an actual peek of the speed at which thesystem works on this date.Table-4: First installation Scheduling Engine load Number of active jobs 706 Number elemental tasks to 49466 reckon with Time to decide what to do 4 NOW (seconds) Time to reschedule: predict micro-level future schedule 25 completely (seconds)Scheduling engine work at a phenomenal speedof about 1900 tasks / second when itreschedules, that happens once every minutemaking the system live. You can guess thedecision to allot tasks now and knowing effect ofall current decisions as schedule prediction areindependent processes. Time to reschedule isdecided by the number of elemental taskspresent and varies linearly. In worst case Page 11 of 13 © 2013, Laxman C Marathe
  12. 12. Exhibit–1: Console Functionality in brief Console Function Number & Location Define and estimate all aspects of an JSW is a multi-use console. Sales orders; persons, Customer SupportJob Study Wizard Simulate or schedule orders; personnel, shop floor Managers(JSW) Monitor order progress; and Supervisors and even Manage / Change order execution; customers all can have one for their CRM functionality. personal use. It is the Operators’ console. Details of all allotted tasks flow in real-time to One WCC can represent one or these consoles for Operators’ to notify several or all work center in a task progress milestones.Work Center Console facility. Users can tailor the Also gives details of all tasks already(WCC) number of WCCs required to cover done and those lined up for execution all work centers on the shop floor. later. System puts no higher limit. Valuable machine statistics and many more helpful features. Any inputs required from customers?Customer Interaction As many as personnel involved in Track, follow-up and notify input whenConsole (CIC) managing customer inputs. they arrive in order of requirement Preventive Maintenance as well as unexpected breakdowns engage work centers and affect the schedule. One can define preventive maintenanceMaintenance Console schedule in advance and treat it like a As many as required.(MTN) maintenance job that can be scheduled like any other order. This console helps define a preventive maintenance program, schedule it and notify its activities. Movement and storage of work-in- progress is a critical function in the value-adding process and affects theMaterial Movement schedule. We designed a console for As many as required.Console (MMC) the person in charge of work-in-progress that performs all functions as required in real-time. Orders may require raw material either sourced from stores or purchased. Need for material is decided and drivenInventory by the scheduling core and thus anManagement entire material management system is As many as required.Consoles (IMCs) created around the scheduling core. This one console takes different avatars depending on what specific inventory functionality is required. Page 12 of 13 © 2013, Laxman C Marathe
  13. 13. Console Function Number & Location System is fully user configurable and all this information resides in one logical database called the factory dB. However, user must have a means toFactory dB Manager modify the factory dB without affecting As many as required.(FDM) current working system. FDM allows one to check-out locally a copy of the factory dB for manipulation / change, revalidate it and check-in the factory dB when finalized. All monetary information generated by the scheduling core is fetchedMoney Management periodically by this console for financial As many as required. Only inConsole (MMM) accounting purposes. One can then concept stage. build or dove tail this information into any existing financial ERP system. Manpower information like past usage, current manning information being used and future requirements too flow fromHuman Resource As many as required. Only in the scheduling core. This console isConsoles (HRC) concept stage. designed to cull out or control such information or feed it into any existing ERP system.References[1] D. Ouelhadj, S. Petrovic - A survey of dynamic scheduling in manufacturing systems - Springer Science:Journal Scheduling (2009) 12: 417–431 - Published online: 28 October 2008[2] Cowling, P.; Johansson, M. - Production, Manufacturing and LogisticsUsing real time information for effective dynamic scheduling - Elsevier: European Journal of OperationalResearch 139 (2002) 230–244[3] Guilherme, E.V.; Herrmann, J.W.; Lin, E. - Rescheduling Manufacturing Systems: A framework ofstrategies, policies and methods - Journal of scheduling, Kluwer Academic Publishers, Netherlands[4] Velaga P., Ph.D. (Scheduling) President, Optisol, 3910 Stony Creek Ln, College Station, Texas 77845 -Advantages & Difficulties with Drag-and-Drop Operations – Web page link: http://www.optisol.biz/Drag-and-Drop.htm[5] Zhang L., Li, X., Gao, L., Yang, Y., Jiang , P. - Predictive/reactive scheduling with uncertain disruptions -proceedings of the 41st international Conference on Computers & Industrial Engineering P 260-265 Page 13 of 13 © 2013, Laxman C Marathe

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