Manual Data Collection

In recent years, corporate databases have improved, companies have invested in information systems, and data mining techniques are more commonly used. Still, we find that we are frequently required to use manual data collection techniques in support of our simulation work.

We have been working with and recommending our friends at Quetech since 2001 whenever we, or our clients, require assistance with time studies. Quetech is the developer of WorkStudy+. This software (for the Palm OS or Pocket PC) allows for streamlined and easy time studies using a handheld PDA.

Here's a quick run-down of how it works:

1. Develop your time study template by following an extremely user-friendly interface in Microsoft Excel.
2. Transfer the template to your handheld(s) using a USB cable.
3. Manually observe your process using a touch pen to record the start, end and category of tasks as well as many other customizable fields. Repeat until you've completed your data collection plan.
4. Transfer the data back to Excel for reporting and built-in statistical analysis.

We recently coached BJC HealthCare through a manual data collection effort with the goal of understanding the resource requirements to dispense medication within a hospital. The BJC study was covered tasks performed by the nursing staff within each unit, as well as order fulfillment tasks performed by pharmacists and technicians. WorkStudy+(combined with a few inexpensive PDAs from Walmart) proved invaluable in the manual data collection effort.

If you find yourself faced with a significant manual data collection project, consider this cost-effective, efficient solution. The days of stop watches, clipboards, and data entry will certainly not be missed.



Finally, a Better Elevator

Maybe I have not been traveling to enough large office buildings or hotels lately, but on a recent visit to the Sheraton New Orleans,  I came across the first truly intelligent elevators I have ever seen. 

We all know how elevators traditionally work - you push an up or down button, wait for the first available car going in your direction, pile in with everyone else and push the button for your desired floor. The elevator then stops in sequence at each floor chosen, meaning you may have several stops before you get to your floor.

The Sheraton's new elevator system approaches the problem differently. Rather than asking passengers to make an up or down selection as a first step, this system requires passengers to select a floor number before they even get onto a car. Once inside the elevator, passengers can no longer make a floor choice. Instead, they only see a list of potential stops.  Moving this critical 'which floor' information one step forward in the process allows the elevator system to group passengers by floor, thereby avoiding the 'milk run' to multiple floors required by traditional elevator set-ups. 

With the new system, as with the old, there is no guarantee that a car will be available for you the instant you want it. But with the intelligent grouping of passengers, you can expect a shorter ride to your final destination.

To a simulation guy who has made a career out of trying to improve systems, this seems revolutionary. I have seen banks of elevators grouped for low floors and high floors, or penthouse only elevators, but I have never seen a truly intelligent elevator system like this one. Once again, maybe I just don't get out enough.

As a simulation instructor, this stuck me as not only a smart system, but also a great learning exercise. So, we are offering a $50 gift certificate to the person who can create the best simulation(s) to compare a traditional elevator with this new "batch" elevator.  If you are interested, please send us an email using the contact form and we will forward you the parameters and assumptions for this little competition.

Select Resource by Label

When SIMUL8's Select Resource by Label feature was introduced, I have to admit that I was initially skeptical about its potential for practical use. However, I recently came across a sticky situation where Select Resource by Label was indeed quite useful.

Here's how the feature works: You allow a work center to dynamically set its resource requirements by referencing a label on the work items bound for the work center. If the value of the label is 1, then the work center requires the first resource in the defined list of resources.  If the value of the label is 2 then the second resource would be required, and so on.

Because the Select Resource by Label feature does not support situations where multiple resources are required, such as a task that requires both a doctor and a nurse, I could not think of an immediate use for this new feature.

Last week, that changed. I had the pleasure of teaching SIMUL8 to a six sigma black belt from a major mortgage lending company. We found that the Select Resource by Label feature would nicely solve a staff allocation issue that would have previously required messy Visual Logic. 

In the situation that came up last week, a new mortgage application must be assigned to an individual mortgage 'specialist'. Once assigned, the 'file' belongs to the same specialist for the duration of the lenghtly application review process.  If we were to model the specialists as a single skill and set the number of resources available equal to the total number of specialists available, the total time in system would not be accurate as the 'pooling' would inaccurately portray capacity.  If Speciality A was not available, all of their files would sit and wait. Specialist B, C, D... would not be covering for them.

To solve this, we:

1. Created a specific resource for each specialist. 
2. Created one (replicated) work center for each manual task in the mortgage application process.
3. Assigned the 'file' to an individual Specialist via a label using a slighly complex 'circulate' assignment algorithm.
4. Used the Select Resource by Label feature to easily reflect which specialist was required by each file for each work center (task) in the process.

This approach offered a number of attractive advantages. It:

• Minimized the number of work centers in the simulation
• Minimized the amount of complex Visual Logic required
• Maintained a nice "Flow Chart" graphical layout of the simulation which enhanced the presentation value of the simulation
• Allowed for flexible and comprehensive staffing schedules
• Allowed for staff specific process times where warranted

Distribution Fitting

I recently came across a good whitepaper about distribution fitting from our friends at Vose Consulting (Vose offers Monte Carlo simulation software and consulting).  This paper provides a nice reminder about curve fitting as well as a detailed lesson in goodness of fit tests. This quick read will come in handy for improving the accuracy of your SIMUL8 models. The paper is available in PDF format:

Fitting distributions to data and why you are probably doing it wrong

by David Vose
Feb. 15, 2010

Create an Interruptible Work Center

Prerequisites:

This discussion assumes that you already have a basic understanding of how to set and use labels. For more complete information on these topics, see our book Learning SIMUL8: The Complete Guide, or ask about our training programs.

Description:

An interruptible work center will accept higher priority work items in the middle of a cycle. Sometimes referred to as 'preempting,' this option causes the work center to set aside the work item it is currently processing to select the higher priority item, process it, then reselect the previous item where it left off. This act of preempting is a bit tricky to get to work properly.

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