METHODS ENGINEERING:GATHERING / ORGANIZING INFORMATION

By -

GATHERING / ORGANIZING INFORMATION

This section will discuss What to study (Pareto), videotaping jobs, searching for solutions, between- operations analysis, and within-operation analysis.

3.1. What to Study (Pareto)

Engineering time is a valuable resource; don’t waste time on unimportant problems. To check quickly whether a project is worth considering, calculate (1) savings / year if material cost is cut 10% and (2) savings / year if labor cost is cut 10%.

The concept of the ‘‘insignificant many and the mighty few’’ (Pareto distribution) is shown in Figure 7. Cause (x-axis) and effect ( y-axis) are not related linearly. The key concept is that the bulk of the problem (opportunity) is concentrated in a few items. Pareto diagrams are a special form of a histogram of frequency counts; the key is that the categories are put into order with the largest first and smallest last; then a cumulative curve is plotted. Therefore, using the Pareto concept, if your design concerns crime, it should concentrate on the few individuals who cause most of the crimes; if it is to improve quality, it should concentrate on the few components that cause most of the problems. See Table 13. Fight the giants!

3.2. Videotaping Jobs

Videotaping is useful for task analysis and for training. Some tips are:

• Have spare batteries and a battery charger. A charger may take eight hours to recharge a battery.

• Use a camera feature that continuously displays the date on the screen; this establishes without question when the scene was shot. You may wish also to photo a card with the operator’s name.

• Plan the location of camera and subject ahead of time. Use a tripod. Multiple views are best. Use some combination of a front view, a side view, a back view, ‘‘stepladder’’ views (a partial- plan view), overall views, and closeup views. Begin a scene with a full view (far shot, wide- angle view) and then zoom as desired.

• If possible, videotape multiple operators doing the same task. This permits comparisons of methods. Small differences can be detected on tape because the tape can be frozen and / or repeated. For example, how are items oriented? Is the sequence of steps the same? Does one operator deviate joints more or less than other operators?

• If the view is perpendicular to the operator front or side, the projected view can be frozen and angles determined on the screen using a protractor. These angles can then be used as input to computer models.

SNAG-0020

• Take lots of cycles for your stock tape. Each scene should have several cycles. You can always edit, but it is expensive to go back and shoot more tape.

• For analysis of time, there are three alternatives:

1. Put a digital clock in the scene.

2. Use a camera–VCR system with a timecode feature, which will allow you to quickly locate any time on the tape.

3. Count the number of frames (VHS has 30 frames / sec [0.033 sec / frame]).

SNAG-0021

• During taping, use audio only as a notepad. For management presentations and training, dub in a voice reading a script.

• The VCR should have both a freeze-frame and single-frame advance.

• For task analysis, have the operator as well as the engineer view the tape. The operator can point out to the engineer what is being done and why—perhaps with audio dubbing. The tape also can show the operator some problems and how other operators do the task.

• For a training or management presentation video, you will need to cut and paste your stock tape. For the script, divide a column of paper into two columns labeled audio and visual. In the audio column, enter the words to be read. In the visual column, enter the tape counter reading (start and stop) of the stock videotape. For your final tape, you also will use text shots created in the studio (title page, points you want to emphasize, conclusions, etc.), studio shots of you, and shots of still photos. Then create the final product by blending all the pieces. Perhaps you can even add music!

Comments

Post a Comment

Popular posts from this blog

DUALITY THEORY:THE ESSENCE OF DUALITY THEORY

By -
Image
THE ESSENCE OF DUALITY THEORY Given our standard form for the primal problem at the left (perhaps after conversion from another form), its dual problem has the form shown to the right. Thus, with the primal problem in maximizatio n form, the dual problem is in minimization form instead. Furthermore, the dual problem uses exactly the same pa r amete r s as the primal problem, but in different locations, as summarized below. 1. The coefficients in the objective function of the primal problem are the right-hand sides of the functional constraints in the dual problem. 2. The right-hand sides of the functional constraints in the primal problem are the coef- ficients in the objective function of the dual problem. 3. The coefficients of a variable in the functional constraints of the primal problem are the coefficients in a functional constraint of the dual problem. To highlight the comparison, now look at these same two problems in matrix notation (as introduced at the beginn...
Read more

NETWORK OPTIMIZATION MODELS:THE MINIMUM SPANNING TREE PROBLEM

By -
Image
THE MINIMUM SPANNING TREE PROBLEM The minimum spanning tree problem bears some similarities to the main version of the shortest-path problem presented in the preceding section. In both cases, an undi r ecte d and connected network is being considered, where the given information includes some mea- sure of the positive length (distance, cost, time, etc.) associated with each link. Both problems also involve choosing a set of links that have the shortest total length among all sets of links that satisfy a certain property. For the shortest-path problem, this property is that the chosen links must provide a path between the origin and the destination. For the minimum spanning tree problem, the required property is that the chosen links must provide a path between ea c h pair of nodes. The minimum spanning tree problem can be summarized as follows: 1. You are given the nodes of a network but not the links. Instead, you are given the po- tential links and the positive length for each ...
Read more

INTEGER PROGRAMMING:THE BRANCH-AND-CUT APPROACH TO SOLVING BIP PROBLEMS

By -
TH E BRANCH-AND-CUT APPROACH TO SOLVING BIP PROBLEMS Integer programming has been an especially exciting area of OR since the mid-1980s be- cause of the dramatic progress being made in its solution methodology. Background To place this progress into perspective, consider the historical background. One big break- through had come in the 1960s and early 1970s with the development and refinement of the branch-and-bound approach. But then the state of the art seemed to hit a plateau. Rel- atively small problems (well under 100 variables) could be solved very efficiently, but even a modest increase in problem size might cause an explosion in computation time be- yond feasible limits. Little progress was being made in overcoming this exponential growth in computation time as the problem size was increased. Many important problems arising in practice could not be solved. Then came the next breakthrough in the mid-1980s, with the introduction of the b r an c h- and-cu t approach to sol...
Read more