Easy-to-learn simulation package targets people who perform business process improvement
By Ronald F. McPherson and John D. Munro
Simulation provides a powerful tool to experiment with ideas without exposing actual assets to risk. For this reason simulation has been called the manager's laboratory . One entry barrier to simulation use in process improvement is that technical specialists need to develop the simulation, and then train the end-user in the use of that simulation. The MIS community is aware of the advantages of involving end-users in MIS/DSS development as evidenced by numerous articles on this subject in the literature. ProcessModel, Inc. offers its solution to end user simulation model development by introducing ProcessModelTM, a process improvement simulation product.
ProcessModel, Inc. promotes ProcessModel 3.01 as a product for the non-technical professional to conduct systematic studies to improve business operations. In the words of the users manual, "ProcessModel is a process re-engineering tool for visualizing, analyzing and improving business processes. Designed specifically for managers and planners, ProcessModel combines simple flowcharting technology with powerful simulation capability to bring flowcharts to life through graphical animation."
ProcessModel presents its simulation engine to the user through Micrografx FlowCharter. Running as an OLE application through FlowCharter, starting ProcessModel places the user in a Micrografx FlowCharter-style window containing one additional menu, the Simulation Menu. The user creates and saves a flow chart of the process under study in ProcessModel using a Flowcharter interface. Then, via the Simulation Menu, the user creates and runs the associated simulation. Coding, animation and output generation are handled automatically by ProcessModel in separate windows. After running a simulation, both the simulation output window and the Flowcharter window are accessible. Standard output provides cost characteristics as well as operational characteristics, such as waiting times, cycle times and utilizations.
Printed and electronic versions of the user's manual are supplied. The printed users manual is actually a two-part manual covering both ProcessModel and the Micrografx FlowCharter (page numbering starts over when you reach the Micrografx FlowCharter manual). Additionally, the CD contains an online tutorial requiring Acrobat Reader’ (supplied on the installation CD). Standard MS Windows-style online help is provided for both ProcessModel and Micrografx FlowCharter.
Currently, two versions of the software are available. The Standard Edition (version reviewed) contains ProcessModel (with Micrografx FlowCharter), online and printed documentation, and full-service technical support. The Professional Edition adds additional capability for process optimization and two days of product training. A full-featured demonstration version which expires 30 days after installation is also available. Reduced model size student versions are planned for early 2000.
ProcessModel runs on an IBM compatible PC within either Windows 95/98 or Windows NT 4.0 Environments. For Windows 95/98 the minimum requirements are a Pentium processor with 24 Mb of RAM, 75 Mb of free disk space, VGA monitor and a mouse. Recommended configuration includes a Pentium processor or higher, 32 Mb of RAM, 100 Mb of free disk space, SVGA monitor and mouse. If you install ProcessModel within Windows NT 4.0, minimum requirements are a Pentium processor, 32 Mb RAM, 100 Mb free disk space, VGA monitor and a mouse. The recommended configuration is a 233 MMX Pentium processor or higher, 64 Mb RAM, 100 Mb free disk space, SVGA monitor and mouse.
We installed and used ProcessModel on both a laptop and desktop using the supplied CD ROM disk. Each time the installation went smoothly and took from eight minutes (first time) to five minutes (second install), including rebooting. In each case complete versions of ProcessModel and Micrografx FlowCharter required 60 Mb total disk. For online documentation we installed the supplied Acrobat3 reader which occupied an additional 50 Mb of disk space.
The configuration of the laptop included a Celeron 366 Mz processor, 64 Mb RAM, 4.6 Gb hard drive, SVGA (1024 x 768) TFT display and a pointing device. The desktop system included a 400 Mz Celeron Processor, 64 Mb RAM, 6.4 Gb hard dive, 17 in. SVGA monitor and mouse.
Constructing a model of a process is straightforward. Through the ProcessModel-augmented Micrografx FlowCharter, the user arranges flowchart elements, enters parameters defining element characteristics, adds any special entity-related attributes, and then saves the flowchart. The creation process features drag-and-drop placement of elements, point-and-click selection of elements and easy-to-use element properties dialog boxes. Anybody familiar with a Windows drawing program should be at ease using ProcessModel to draw the flowchart.
Through the FlowCharter interface, ProcessModel provides objects, connections and various other model elements. Objects can represent moving entities, processing activities, storage locations and resources. Connections define entity routings and resource assignments to activities (i.e. a worker or machine that carries out an activity). Parameters include entity arrival characteristics, routing characteristics, order signals (i.e. re-order point levels) and priorities. Other model elements include distributions, entity attributes, variables, action logic, and shift and break schedules for resources and activities.
To build our first model we used the example found in the User Manual on pages 37 60 (also example #2 in the tutorial). After building the model, we developed the model presented below. For those needing to gain some background into simulation we recommend the online tutorial. ProcessModel, Inc. recommends their two-day training session for new users of their software.
Scenario. First, visualize the process; entities that enter the process, routes that entities follow, activities that transform the moving entities, people or machines that perform the activities. Our second model is a telephone answering facility. The facility staff is comprised of two operators and a manager. The operators answer phone calls while the manager tends to supervisory tasks and answers calls. Calls that arrive at the switchboard are answered by an operator. If both operators are busy, the calls are immediately switched to the manager's phone. When the manager's phone rings the manager immediately ceases other tasks to answer the phone. If the manager's phone is also busy, the caller immediately receives a busy signal. Calls arrive according to a triangular distribution with a minimum of one minute, a most likely value of three minutes and a maximum of four minutes. Both the operators and the manager handle calls according to an exponential distribution with a mean service time of three minutes. The manager has enough supervisory tasks to always keep busy while not handling phone calls.
Model development. Begin building the model by drawing objects and their connections to represent the call arrivals, the operator's answering activity, manager's answering activity, manager's other tasks activity, staff resources, relationships of staff to activities and routing of calls. Objects and connections are selected from a palette, dragged and dropped into position, and then named. Figure 1 shows the resulting flowchart of the process along with the object selection palette. The dashed lines indicate which staff perform the various activities. Entity routings are represented by the solid lines. Calls have alternate routes (to operators, to manager, or busy signal) out of the system. The telephone icon represents the input source for incoming calls. The file cabinet icon represents the input source for supervisory tasks.
Figure 1: FlowCharter model layout.
Next, set model parameters by specifying values for the properties the objects and connections. Double-clicking an object or connection causes that element's properties to be displayed in a Properties Dialog Box. Default parameter values may be changed by selecting alternative values from drop-down lists or by typing new values. The parameters define call arrival characteristics, process times of the activities, activity capacities, activity queue capacities, resource connection types (relationships of workers to the activities including interrupting the manager to answer a new call), number of various staff, call routing characteristics and call move times along the routings. Figure 2 illustrates setting the properties of the route between the Operator Takes Call and Manager Takes Call activities. The "Renege" type of route indicates that a call is sent to the Manager Takes Call activity after sitting in the Operator Takes Call queue for zero minutes (see Renege After property). The optional New Name, specified as To_Manager in Figure 2, will cause statistics to be kept on the number of reneges. The other tabs can set properties pertaining to costs, special logic and advance naming all associated with this route. We did not use these properties. Once all object properties are defined the model design is complete.
Figure 2: Setting entity routing properties.
Running Simulation And Simulation Output
Use the Simulation Menu to set initial running options and start the simulation. Before starting the simulation options concerning run length, warm-up length, number of replications, report characteristics and animation may be changed from their defaults. Once satisfied with the run options, start the model by clicking on the Save and Simulate command on the Simulation Menu. If you want to save the model to an alternate file, first use the Save As command on the File Menu, and then start the simulation. Clicking the Simulate command translates the flowchart into the simulation program, creates animation features and starts execution of the simulation. Figure 3 displays the simulation animation screen. From the animation screen the display may be zoomed or disabled, and execution speed varied or paused. The scoreboard shows current statistics on entities. Values above and below the activities give the queue contents and activity contents, respectively. The circles above the resources change color to indicate resource use status. For example, green indicates available, blue indicates in use and red indicates unavailable. Elapsed time is show in the upper right corner of the animation screen.
Figure 3: Simulation animation screen.
The conclusion of the simulation run provides a standard array of statistics for the objects. This output is displayed in a separate output window. Figure 4 contains a snapshot of the output screen. Closing the output window returns the user to the flow chart window.
Figure 4: Simulation output window.
Highpoints And Hurrahs
ProcessModel's interface and automatic programming lowers the entry barriers for non-operations specialists to enjoy the advantages that simulation analysis affords to process improvement. ProcessModel, Inc.does recommend their two-day course for those new to simulation analysis. As an added advantage their interface should allow students learning simulation for the first time to concentrate on simulation analysis techniques rather than on learning a new programming language. The straightforward interface reduced development errors, and the error messages, stated in human language terms, were easily understandable The visual layout of the model helps avoid logic errors resulting from process misrepresentation. ProcessModel provides many other options such as user-created icon palettes that allow the user to customize the system.
Concerns And Cautions
While using the modeling system we encountered a number of areas where care must be exercised. For example, the labels in Property Dialog boxes were not always linked to the labels on chart objects. Depending on the sequence in which the objects were created and connected, the user intending to delete one object may also delete other objects. For example, deleting an activity may also delete all associated connections. Costing calculations seem to double count resource costs when the "Respond Immediately" box is checked, which may not be desirable under certain circumstances. Certain advanced features did not operate as described. Most notably, the "Respond Immediately" and entity priority features should be thoroughly understood with respect to how they affect a model before incorporating them into a simulation. Finally, we were able to generate situations using advanced features where the simulation resources incorrectly stopped responding before the simulation ended. ProcessModel, Inc. is aware of these concerns and is working to correct or clarify them in future releases.
ProcessModel is an easy to learn and use simulation package targeted toward the audience best positioned to improve business processes the people who perform the processes. The user-friendly interface allows end-users to build and run process simulation models using easy to understand graphics, and commonly understood drag-and-drop and point-and-click technology. Advanced features are provided to model complex situations for advanced simulation developers. As a teaching tool ProcessModel provides an opportunity to open simulation as a viable analysis method to a more general student audience. This could eventually create a better understanding and awareness in the general business community of the role of simulation (a 1993 Department of Defense report  credits unawareness of simulation capabilities as a major reason for not using it for process improvement). ProcessModel allows the user to focus on the process under study instead of on the technology of simulation.
The authors want to thank the marketing and technical staff at ProcessModel, Inc. for the timely and straight-forward replies to our inquiries.
Ron McPherson is an associate professor in the Business Division at the University of the Virgin Islands on the island of St. Croix in the United States Virgin Islands, where he currently teaches CIS courses at both the graduate and undergraduate levels. John Munro is an associate professor of Computer Information Systems, Business Administration Division, St. Croix Campus, University of the Virgin Islands. He has consulted in energy, transportation, alternative technology and business information systems for large and small organizations..
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