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In this example, there is no change in other periods because production is constant under the smooth production option. If production decreases, the decrease appears in this column. Example 7: Increase and decrease charging The previous example had increases and decreases in production. These increases and decreases are accounted for by regular time production. In the following screen, the regular time capacity is reduced in order to force production through regular time and overtime. Notice that the increase column only has a value in it in the second period when regular time production went from to units.
The regular time production remains at ; even though overtime increases, this does not show up in the increase columns. There are no charges against overtime or subcontracting increases.
The only difference is that the transportation model does not consider changes in production levels, so there is no data entry allowed for increase and decrease costs or for units last period. The creation screen will ask for the number of periods and whether shortages are allowed. The similarity to the previous input screens can be seen as follows. Notice that there is only one entry for each of the costs.
Thus, this model can not be used for situations where the costs change from period to period. You must formulate these problems yourself using the transportation model from the Module menu rather than this transportation submodel of aggregate planning. Note: The transportation model that is the second submodel in the New menu can also be accessed as the last method in the first submodel, The solution screen is displayed next.
The window on the right summarizes the production quantities, unit-months of holding and shortage if applicable , and the costs. It is even more obvious that this is a transportation problem if the second window of output which is the transportation model itself is examined.
The large numbers 9, have been entered in order to preclude the program from backordering. If you like, this table could be copied; you could then open the Transportation model, create a new empty table that is 13 by 4 and paste this data in to that table. Five heuristic rules can be used for performing the balance.
The cycle time can be given explicitly or the production rate can be given and the program will compute the cycle time. This model will not split tasks. Task splitting is discussed in more detail in a later section. The Model The general framework for assembly-line balancing is dictated by the number of tasks that are to be balanced.
These tasks are partially ordered, as shown, for example in the precedence diagram that follows. The five heuristic rules that can be chosen are as follows: 1. Longest operation time 2. Most following tasks 3. Ranked positional weight 4. Shortest operation time 5. Note that tie breaking can affect the final results. The remaining parameters are as follows: Cycle time computation. The cycle time can be given in one of two ways.
One way involves giving the cycle time directly as shown in the preceding screen. Although this is the easiest method, it is more common to determine the cycle time from the demand rate. The cycle time is converted into the same units as the times for the tasks. See Example 2. Task time unit. The time unit for the tasks is given by this drop-down box. You must choose seconds, hours, or minutes. Notice that the column heading for the task times will change as you select different time units.
Task names. The task names are essential for assembly-line balancing because they determine the precedences. Case does not matter. Task times. The task times are given. Enter the precedences, one per cell.
If there are two precedences they must be entered in two cells. In fact, a comma will not be accepted. Notice that in the precedence list in the previous screen both a and A have been typed. As mentioned previously, the case of the letters is irrelevant. Example 1 In this example there are six tasks, a through f. The precedence diagram for this problem appears previously. The time to perform each task is above the task.
Also, note that the tasks that are ready at the beginning of the balance are tasks a and b. Finally, in this first example, we use a cycle time of Solution The following screen contains the solution to the first example. The solution screen consists of two windows as shown in the following screen. The window on the left gives the complete results for the method chosen whereas the window on the right gives the number of stations required not the theoretical number when using each balancing rule.
The solution screen will always have the same appearance and contain the same information regardless of the rule that is chosen for the balance. This is not always the case as is demonstrated later in this section. Station numbers. The station numbers appear in the far left column. They are displayed only for the first task that is loaded into each station. In this example, three stations are required. The tasks that are loaded into the station are listed in the second column. In this example, Tasks b, e, and a are in Station 1; Tasks d and c are in Station 2; and Task f is in station 3.
The length of time for each task appears in the third column. Time left. The length of time that remains at the station is listed in the fourth column. The last number at each station is, of course, the idle time at that station. The idle times are colored in red. For example, there is 1 second of idle time at Station 1, 1 second of idle time at Station 2, and 2 seconds of idle time at Station 3, for a total of 4 seconds of idle time per cycle.
Ready tasks. The tasks that are ready appear here. A ready task is any task that has had its precedences met. This is emphasized because some books do not list a task as ready if its time exceeds the time remaining at the station. Also, if the number of characters in the ready task list is very long, you might want to widen that column. The cycle time that was used appears below the balance.
This cycle time was either given directly or computed. In this example, the cycle time was given directly as 10 seconds. Time allocated. The total time allocated for making each unit is displayed. This time is the product of the number of stations and the cycle time at each station. In this example there are three stations, each with a cycle time of 10 seconds, for a total work time of 30 station-seconds.
The time needed to make one unit. This is simply the sum of the task times. Idle time. This is the time needed subtracted from the time allocated.
Efficiency is defined as the time needed divided by the time allocated. Balance delay. The balance delay is the percentage of wasted time or percent minus the efficiency. Minimum theoretical number of stations. This is the total time to make 1 unit divided by the cycle time and rounded up to the nearest integer. In this example, 26 seconds are required to make 1 unit divided by a second cycle time for an answer of 2.
In addition, a second window opens that displays the number of stations required using each of the different balancing rules. In this particular case, each rule led to the same number of stations, 3. This is not always the case as shown in Example 4. The precedence graph can be displayed see the end of this section , as well as a bar graph indicating how much time was used at each station.
These are shown at the end of this section. In addition, if there is idle time at every station, a note will appear at the top indicating that the balance can be improved by reducing the cycle time. For example, because there are idle times of 1, 1, and 2 seconds at the three stations, we could reduce the cycle time by 1 second. Example 2: Computing the cycle time Suppose that for the same data a production rate of units in 7. Other Rules Other rules that may be used are mentioned although the results are not displayed.
Please note that this is one of the modules where if you change the method using the drop-down box from the solution screen, the problem will immediately be resolved.
That is, you do not need to use the EDIT button and return to the data. Most Following Tasks A common way to choose tasks is by using the task with the most following tasks. Notice from the diagram at the beginning of the section that a has three tasks following it, and b also has two tasks following it.
Therefore, there is a tie for the first task. If Task a is chosen then the next task chosen will be Task b because Task b has 3 following tasks whereas Task c has only one. The task with the largest weight is scheduled first if it will fit in the remaining time. Notice that e has a higher ranked positional weight than c. Least Number of Followers The last rule that is available is the least number of followers.
Example 3: What to do if longest operation time will not fit Some books and some software do not apply the longest operation time rule properly. If the task with the longest time will not fit into the station, the task with the second longest time should be placed in the station if it will fit.
In the following screen data is presented for eight tasks. Notice that Tasks b, c, e, and f immediately follow Task a. The balance appears in the following screen for a cycle time of 5 seconds. After Task a is completed, tasks b, c, d, and e are ready. Task b is longest but will not fit in the 4 seconds that remain at Station 1. Therefore, Task c is inserted into the balance. Example 4: Splitting tasks If the cycle time is less than the amount of time to perform a specific task, there is a problem.
We perform what is termed task splitting but which in reality is actually duplication. For example, suppose that the cycle time is 2 minutes and some task takes 5 minutes.
The task is performed 3 times by three people at three machines independent of one another. The effect is that 3 units will be done every 5 minutes, which is equivalent to 1 unit every 1. Now, the actual way that the three people work may vary.
Although other programs will split tasks, the assumptions vary from program to program. Rather than making assumptions, you should split the tasks by dividing the task time appropriately.
Suppose that in Example 1 a cycle time of 5 seconds was used. Then it is necessary to replicate both Tasks d and f because they will not fit in the cycle time. The approach to use is to solve the problem by dividing the task times by 2, because this replication is needed. The results are presented in the following screen.
Notice that different rules lead to different minimum numbers of stations! The first is a precedence graph, as shown in the following figure. Please note that there may be several different ways to draw a precedence graph. The second graph not displayed here is of time used at each station. In a perfect world these would all be the same a perfect balance. The model is a special case of the transportation method. In order to generate an assignment problem, it is necessary to provide the number of jobs and machines and to indicate whether the problem is a minimization or maximization problem.
The number of jobs and number of machines do not have to be equal but usually they are. Objective function. The objective can be to minimize or to maximize. This is set at the creation screen but can be changed in the data screen. Example 1 The following table shows data for a 7-by-7 assignment problem. The goal is to assign each salesperson to a territory at minimum total cost.
There must be exactly one salesperson per territory and exactly one territory per salesperson. The data structure is nearly identical to the structure for the transportation model. The basic difference is that the assignment model does not display supplies and demands because they are all equal to one.
Note: To try to preclude an assignment from being made, such as Bruce to Pennsylvania in this example, enter a very large cost. The assignments can also be given in list form, as shown in the following screen. The marginal costs can be displayed also. Cost-volume analysis is used to find the point of indifference between two options based on fixed and variable costs.
A breakeven point is computed in terms of units or dollars. Breakeven analysis is simply a special case of cost-volume analysis where there is one fixed cost, one variable cost, and revenue- per-unit. Cost-Volume Analysis In cost-volume analysis, two or more options are compared to determine what option is least costly at any volume.
The costs consist of two types - fixed costs and variable costs, but there may be several individual costs that comprise the fixed costs or the variable costs. In the example that follows, there are five different individual costs and two options.
Data Cost type. Each type of cost must be identified as either a fixed cost or a variable cost. The default is that the first cost in the list is fixed and that all other costs are variable. These values can be changed by using the drop-down box in that cell. The specific costs for each option are listed in the two right columns in the table. If a volume analysis is desired, enter the volume at which this analysis should be performed. The volume analysis will compute the total cost revenue at the chosen volume.
If the volume is 0, no volume analysis will be performed other than for the breakeven point. Volume analysis is at units. In the preceding screen there are five costs with some fixed and some variable.
The program displays the following results: Total fixed costs. For each of the two options, the program takes the fixed costs, sums them, and lists them in the table.
Total variable costs. The program identifies the variable costs, sums them, and lists them. Breakeven point in units. The breakeven point is the difference between the fixed costs divided by the difference between the variable costs, and this is displayed in units. In the example, it is units. Breakeven point in dollars. The breakeven point can also be expressed in dollars. A volume analysis has been performed for a volume of units.
The total fixed costs and total variable costs have been computed for each option and these have been summed to yield the total cost for each option.
A graph is available, as follows. Data entry for this option is slightly different in that the program creates a column for costs and a column for revenues. The fixed and variable costs get entered in the cost column and the revenue per unit is placed in the revenue column. This model requires exactly three inputs. This example could also have been solved using the cost-volume submodel. Select two options and let one be the costs and one be the revenues.
Place the fixed costs and variable costs in their obvious cells; use no fixed cost for the revenue and use the revenue per unit as a variable cost, displayed as follows. The following screen demonstrates the output for a three-option breakeven. The screen indicates that there are three breakeven points as it makes comparisons for Computer 1 versus Computer 2, Computer 1 versus Computer 3, and Computer 2 versus Computer 3.
Of course, even though there are three breakeven points, only two of them are relevant. This is seen a little more easily by looking at the following breakeven graph.
The breakeven point at 40, units does not matter because at 40, units the two computers that break even have higher costs than the Computer 2 option. The data for this example consist of a stream of inflows and a stream of outflows. In addition, for finding the net present value an interest rate must be given. Net Present Value Consider the following example. The company would like to know the net present value using an interest rate of 10 percent.
The data screen follows. The screen has two columns for data. One column is labeled Inflow and the other column is labeled Outflow. At the time of problem creation a six-period problem was created and the data table includes the six periods plus the current period 0. The six savings in the second column are inflows, and they are placed in the inflow column for Periods 1 through 6.
The salvage value could be handled two ways, and we have chosen the way that we think gives a better display. Instead, it is represented as a negative outflow. This keeps the meaning of the numbers clearer.
The last item to be entered is the interest rate in the text box above the data. To the right of this, the inflows and outflows are multiplied by these present value factors, and the far right column contains the present values for the net inflow inflow minus outflow on a period-by-period basis. Internal Rate of Return The computation of the internal rate of return is very simple. The data is set up the same way but the method box is changed from net present value to internal rate of return.
The results appear as follows. You can see that the internal rate of return for the same data is The Decision Table Model The decision table can be used to find the expected value, the maximin minimax , or the maximax minimin when several decision options are available and there are several scenarios that might occur.
Also, the expected value under certainty, the expected value of perfect information, and the regret opportunity cost can be computed. The general framework for decision tables is given by the number of options or alternatives that are available to the decision maker and the number of scenarios or states of nature that might occur.
In addition, the objective can be set to either maximize profits or to minimize costs. Scenario probabilities. For each scenario it is possible but not required to enter a probability. The expected value measures expected monetary value, expected value under certainty, and expected value of perfect information require probabilities, whereas the maximin minimax and maximax minimin do not.
Profits or costs. The profit cost for each combination of options and scenarios is to be given. Hurwicz alpha. The Hurwicz value is used to give a weighted average of the best and worst outcomes for each strategy row. Please note that the Hurwicz value is not in every textbook.
The possible scenarios states of nature are that demand will be low, normal, or high; or that there will be a strike or a work slowdown. The table contains profits as indicated.
The first row in the table represents the probability that each of these states will occur. The remaining three rows represent the profit that we accrue if we make that decision and the state of nature occurs. For example, if we select to use overtime and there is high demand, the profit will be Solution The results screen that follows contains both the data and the results for this example.
Expected values. Row minimum. For each row, the minimum element has been found and listed. This element is used to find the maximin or minimin. For each row, the maximum element in the row has been found and listed. This number is used for determining the maximax or minimax. These represent 40 percent multiplied by the best outcome plus 60 percent multiplied by the worst outcome for each row.
For example, for subcontracting the Hurwicz is. Maximum expected value. Because this is a profit problem finding the maximum values is of importance. The maximum expected value is the largest number in the expected value column, which in this example is In this example, the maximin is The maximax is the largest value in the table or the largest value in the maximum column. In this example, it is Perfect Information A second screen of results presents the computations for the expected value of perfect information as follows.
Perfect information. In this row, the best outcome for each column is listed. For example, for the low demand scenario the best outcome is the given by using overtime. The expected value under certainty is computed as the sum of the products of the probabilities multiplied by the best outcomes. Expected value of perfect information.
The expected value of perfect information EVPI is the difference between the best expected value Table values. The values in the table are computed for each column as the cell value subtracted from the best value in the column in the data. For example, under low demand the best outcome is The two columns on the right yield two sets of results.
There also is a window not displayed in this manual that yields Hurwicz values for alpha ranging from 0 to 1 by. Decision Trees Decision trees are used when sequences of decisions are to be made. The trees consist of branches that connect either decision points, points representing chance, or final outcomes.
All decision tables can be put in the form of a decision tree. The converse is not true. Note: Version 4 of the software includes two different input styles for decision trees. The first model has tabular data entry whereas the second model is easier to use because it has graphical data entry. The first model has been maintained in the software for consistency with previous versions.
Example 2: A decision tree — Graphical user interface One of the models allows for decision trees to be entered graphically rather than in the table as given previously.
This model can be used to examine the same example just completed. After selecting the model, the interface will be displayed as follows. This is the only model in the software that has an input interface that is not the usual data table interface.
The graph is displayed in the large area on the left and created using the tools on the right. In the beginning, there is only one node. The next step is to add two event nodes to node 1. The tool on the right is set to node 1.
The default for node 1 is that it is a decision node as needed in this case. A button is available to change the node if this becomes necessary. The new tree appears as follows.
The current node is node 2, which is indicated by both the fact that the node number in the upper right is node 2 and by the fact that the branch to node 2 is highlighted in a different color.
At this point, two branches need to be added to node 2. The default is to add decision branches to events and vice versa. The type of node can always be changed later. This yields the following diagram. After all data has been entered, click on the Solve button on the toolbar. The data is in black and the solution is in blue as usual.
Notice that branches that should be used are indicated in blue. In the past, an airline has observed a demand for meals that are sold on a plane as given in the following table. How many meals should the airplane stock per flight?
The program is requesting three profits as well as the obvious demands and probabilities. Profit per unit. This is the normal profit for units bought and sold. Profit per unit excess. This is the profit for units that are overordered. In some cases, where there is a salvage value that exceeds the cost of the unit this will be a profit whereas in other cases this will be a loss. Profit per unit short. This is the profit for units when not enough units are ordered. It will be a profit if you can purchase units to sell after the fact at a cost less than the selling price.
Otherwise it will be a 0 or possibly a loss. If there were no voucher there would be no profit or loss for units for the demands that could not be satisfied. Demands and probabilities. Enter the list of demands and their associated probabilities. The airline should order 20 meals to maximize its expected profit. Notice that the cities and the factors have been named.
The output is very straightforward and consists of the following: Total weighted score. For each city, the weights are multiplied by the scores for each factor and summed. The total is printed at the bottom of each column. The first type of model is when past data sales are used to predict the future demand.
This is termed time series analysis, which includes the naive method, moving averages, weighted moving averages, exponential smoothing, exponential smoothing with trend, trend analysis, linear regression, multiplicative decomposition, and additive decomposition. The second model is for situations where one variable demand is a function of one or more other variables.
This is termed multiple regression. There is overlap between the two models in that simple one independent variable linear regression can be performed with either of the two submodels. In addition, this package contains a third model that enables the creation forecasts given a particular regression model, and a fourth model that enables the computation of errors given demands and forecasts.
Time Series The input to time series analysis is a series of numbers representing data over the most recent n time periods. Although the major result is always the forecast for the next period, additional results presented vary according to the technique that is chosen. When using trend analysis or seasonal decomposition, forecasts can be made for more than one period into the future. The summary measures include the traditional error measures of bias average error , mean squared error, standard error, mean absolute deviation MAD , and mean absolute percent error MAPE.
Note: Different authors compute the standard error in slightly different ways. That is, the denominator in the square root is given by n — 2 by some authors and by n — 1 by others. If you have a Pearson textbook the denominator should match the one in your text. If not, POM-QM for Windows uses n — 2 in the denominator for simple cases and always displays the denominator in the output. Week Sales January 3 January 10 January 17 January 24 January 31 February 7 The general framework for time series forecasting is given by indicating the number of past data points.
The preceding example has data for the past six periods weeks , and the forecast for the next period - period 7 February 14 is needed. Forecasting method. The drop-down method box contains the eight methods that were named at the beginning of this module plus a method for users to enter their own forecasts in order to perform an error analysis.
Of course, the results depend on the forecasting method chosen. A moving average is shown in the preceding screen. Number of periods in the moving average, n.
To use the moving average or weighted moving average, the number of periods in the average must be given. This is some integer between 1 and the number of time periods of data. In the preceding example, 2 periods were chosen, as seen in the extra data area. Demand y or Values for dependent y variable. These are the most important numbers because they represent the data.
The data is in the demand column as , , , , , and Solution The solution screens are all similar, but the exact output depends on the method chosen. For the smoothing techniques of moving averages weighted or unweighted and single exponential smoothing, there is one set of output, whereas for exponential smoothing with trend, there is a slightly different output display.
For the regression models, there is another set of output. The first available method is the naive method which simply uses the data for the most recent period as the forecast for the next period. Begin with the moving averages. The main output is a summary table of results. The computations for all of these results can be seen on the following details window. If you are a myomlab user then the toolbar will appear as below with two extra tools to be used for pasting from myomlab.
The first tool performs the paste and the second gives help on pasting from myomlab, if needed. This is what you press after you have entered the data and you are ready to solve the problem. Alternatively, you may use File, Solve or press the [F9] key. This is how you go back and forth from entering data to viewing the solution.
For two modules, linear programming and transportation, there is one more command that will appear on the standard toolbar. This is the STEP tool not displayed in the figure , and it enables you to step through the iterations, displaying one iteration at a time. Below the standard toolbar is a format toolbar. This toolbar is very similar to the toolbars found in Excel, Word, and other Windows programs.
It too can be customized, moved, hidden, or floated. There is one more toolbar, and its default location is at the bottom of the screen. This bar is a utility bar and it contains six tools.
A module list can appear in two ways either by using this tool or the Module option on the main menu. The next two tools will load files in alphabetical order either forward or backward.
This is very useful when reviewing a number of problems in one chapter, such as the sample files that accompany this manual. In the center are two areas, one of which is the main data table. The table contains a heading or title, and rows and columns. The number of rows and columns depends on the module, problem type, and specific problem. The large area with no grid is the table background. The caption colors, table colors, and background color can be changed by using Format, Colors, as explained in Chapter 3.
Above the data table is an area named the extra data bar for placing extra problem information. Sometimes it is necessary to indicate whether to minimize or maximize, sometimes it is necessary to select a method, and sometimes some value must be given.
These generally appear above the data. On the right of the extra data panel is an instruction panel. There is always an instruction here to help you to determine what to do or what to enter. When data is to be entered into the data table, this instruction will explain what type of data integer, real, positive, etc.
The instruction location can be changed by using the View option. There also is a form for annotating problems. A comment may be placed here. When the file is saved, the comment will be saved; when the file is loaded, the comment will appear and the comment may be printed if so desired.
The leftmost panel displays the module and submodel name as you select different modules, as exemplified in this illustration where the module is Forecasting and the submodel is Time Series Analysis. The center panel contains the type of screen data, results, menu, graph, etc. The status bar can be hidden by using the View option. This panel cannot be moved. Although not all problems or modules are identical, there is enough similarity among them that seeing one example will make it very easy to use any module in this software.
As mentioned in the introduction, the first instruction is to select a module to begin the work. In the preceding figure, the modules are displayed as they are listed when you use the MODULE tool on the utility bar as opposed to the Module option in the main menu at the top. They are divided into three groups. The models in the first group typically are included in all POM and QM books, whereas the models in the second group typically appear only in POM books, and the models in the third group appears only in QM texts.
The models are divided in 1 If the software is set to accompany the Krajewski, Ritzman, Malhotra textbook then the names of the menu items will be different in order to match chapter names in the textbook. Please see the appendix. If you choose the Module option from the main menu, you get the same modules listed in a single list in alphabetical order.
This is displayed in Chapter 3. Creating a New Problem Generally, the first menu option that will be chosen is File, followed by either New, to create a new data set, or Open, to load a previously saved data set. In the figure that follows, the creation screen that is used when a new problem is started is displayed. Obviously, this is an option that will be chosen very often. The creation screens are similar for all modules, but there are slight differences that you will see from module to module.
The top line contains a text box into which the title of the problem can be entered. The default title for problems is initially untitled. The default title can be changed by pressing the button [Modify Default Title]. For example, if you change the default title to Homework Problem, then every time you start a new problem the title will appear as Homework Problem, and you would simply need to add the problem number to complete the title.
If you want to change the title after creating the problem, this can easily be done by using the Format, Title option from the main menu or from the toolbar. Rows will have different names depending on the module. For example, in linear programming, rows are constraints, whereas in forecasting, rows are past periods. At any rate, the number of rows can be chosen with either the scrollbar or the text box. As is usually the case in Windows, they are connected.
As you move the scrollbar, the number in the text box changes; as you change the text, the scrollbar moves. In general, the maximum number of rows in any module is There are three ways to add or delete rows or columns after the problem has been created. This program has the capability to allow you different options for the default row names.
Select one of the six option buttons in order to indicate which style of default naming should be used. In most modules, the row names are not used for computations, but you should be careful because in some modules most notably Project Management and Material Requirements Planning the names might be relevant to the computations. In most modules, the row names can be changed by editing the data table.
Many modules require a number of columns. This is given in the same way as the number of rows. The program gives you a choice of default values for column names in the same fashion as row names but on the tab Column Names. An overview tab is included on the creation screen in this version of the software. The overview tab gives a brief description of the models that are available and also gives any important information regarding the creation or data entry for that module.
Some modules, such as the linear programming example displayed previously, will have an extra option box, such as for choosing minimize or maximize or selecting whether distances are symmetric. Select one of these options. In most cases, this option can be changed later on the data screen. At this point, a blank data screen will appear as in the following figure.
Screens will differ module by module but they will all resemble the following screen. The Data Screen The data screen was described briefly in Chapter 1. It has a data table and, for many models, there is extra information that appears above the data table follows.
Entering and Editing Data After a new data set has been created or an existing one has been loaded, the data can be entered or edited. Every entry is in a row and column position. You navigate through the spreadsheet using the cursor movement keys or the mouse. These keys function in a regular way with one very useful exception the [Enter] key. The [Enter] key takes you to the next cell in the table, first moving to the right and then moving down. When a row is finished, the [Enter] key goes to the first cell in the next row that contains data rather than a row name.
For example, in the previous It is possible to set the cursor to go to the first cell, the one with the name in it, by using Help, User Information.
In addition, if you use the [Enter] key to enter the data, after you are done with the last cell, the program will automatically solve the problem saving you the trouble of clicking on the SOLVE tool. This behavior can be adjusted by using Help, User Information and, in addition, if you want the program to automatically prompt you to save the file when you are done entering data, this too can be accomplished through Help, User Information.
The instruction frame on the screen contains a brief instruction describing what is to be done. There are essentially three types of cells in the data table. One type is a regular data cell into which you enter either a name or a number.
When entering names and numbers, simply type the name or number, then press the [Enter] key, one of the direction keys, or click on another cell. If you type an illegal character, a message box will be displayed indicating so. A second type is a cell that cannot be edited.
For example, the empty cell in the upper left-hand corner of the table can not be edited. You actually could paste into the cell. A third type is a cell that contains a drop-down box. For example, the signs in a linear programming constraint are chosen from this type of box, as shown in the following illustration. To see all of the options, press the arrow on the drop-down box.
When you are finished entering the data, press the SOLVE tool on the toolbar or use [F9] or File, Solve and a solution screen will appear as given in the following illustration. The original data is in black and the solution is in a color. Of course, these are only the default values; as all colors may be set using Format, Colors. This can be seen by the icons given at the bottom.
Click on these to view the information. Alternatively, when you solve the problem, the form below can be set to appear on top of the solution through Help, User Information.
The options are as follows: The first option simply displays the solution. The next three options remind you that more results may exist than the one window displayed. The second option displays the Solutions Window, which contains a brief description of each solution Window. The third option automatically drops down the Window menu.
These options can be reset using Help, User Information. It is generally at this point that, after reviewing the solution, you would choose to print both the problem and solution.
Now that the creation and solution of a problem have been examined, all of the options that are available in the main menu are explained. These options are now described. New As demonstrated in the sample problem, this option is chosen to begin a new problem or file. In some cases, you will go directly to the problem creation screen, whereas in other cases a pop-up menu will appear indicating the submodels that are available. After selecting a submodel, you will go to the creation screen. File selection is the standard Windows common dialog type.
An example of the screen for opening a file follows. Notice that the extension for files in the software system is given by the first three letters of the module name. When you go to the Open File dialog, the default value is for the program to look for files of the type in this module. This can be changed at the bottom left, where it says Files of type.
Otherwise, file opening and saving is quite normal. It is possible to use Help, User Information to set the program to automatically solve any problem when it gets loaded. This way, if you like, you can be looking at the solution screen whenever you load a problem rather than at the data screen.
Save Save will replace the file without asking you if you care about overwriting the previous version of this file. If you try to save and have not previously named the file, you will be asked to name this file.
That is, the command will function as Save As. This option is very similar to the option to load a data file. It is essentially identical to the one previously shown for opening files. The names that are legal are standard Windows file names. In addition to the file name, you may preface the name with a drive letter with its colon or path designation.
The software will automatically append an extension to the name that you use. As mentioned previously, the extension is the first three letters of the module name. You may type file names in as uppercase, lowercase, or mixed. Examples of legal file names are sample, sample. If you enter sample. For example, if the module is linear programming, the name under which the file will be saved will be sample. Save as Excel File The software has an option that allows you to save most but not all of the problems as Excel files.
The data is transported to Excel and the spreadsheet is filled with formulas for the solutions. In some cases, Excel s Solver may be required in order to get the solution.
For example, following is the output from a waiting line model. The left-hand side has the data, whereas the right-hand side has the solution.
Notice from the formula for cell E7 shown at the top of the spreadsheet that a spreadsheet with formulas was created.
That is, we did not cut and paste the above screen into Excel which is possible but instead created an Excel spreadsheet with appropriate formulas. Print Print will display a Print Setup screen. Printing options are described in Chapter 4. Both Save and Print act slightly differently if a graph is being displayed at the time that you use Print or Save.
Print Screen Print Screen will print the screen as it appears. Different screen resolutions may affect the printing. Printing the screen is more time consuming than a regular print.
Use this option if you need to demonstrate to your instructor exactly what was on the screen at the time. Solve There are several ways to solve a problem. Clicking on File, Solve is probably the least efficient way to solve the problem. The toolbar icon may be used, as well as the [F9] key. Also, if the data is entered in order top to bottom, left to right, using [Enter] , the program will solve the problem automatically after a value is entered into the last cell.
After solving a problem, the Solve option will change to an Edit option on both the menu and the toolbar. This is the way to go back and forth between data and solutions.
Note that Help, User Information may be used to set the program to automatically maximize the solution windows if so desired. Step For the linear programming and transportation modules, a Step option not displayed in the preceding figure will appear in the File menu and on the toolbar.
Exit The next option on the File menu is Exit. This will exit the program. You will be asked if you want to exit the program. You can eliminate this question by using Help, User Information.
Clicking on one of these will load the file. Edit The commands under Edit can be seen in the following illustration. Their purposes are threefold.
The first six commands are used to insert or delete rows or columns. The second type of command is useful for repeating entries in a column, and the third type is for cutting and pasting between Windows applications. Insert Row inserts a row after the current row, and Insert Column inserts a column after the current column. Insert Rows s and Insert Columns s ask you how many columns or rows you would like to insert after the current row or column.
Delete Row deletes the current row, and Delete Column deletes the current column. Copy Entry Down Column The Copy Down command is used to copy an entry from one cell to all cells below it in the column.
This is not often useful, but it can save a great deal of work when it is. Copy Copy has five options available. It is possible to copy the entire table, the current row, or the current column to the clipboard. It is possible to copy from the data table or any of the solution tables. Whatever is copied can then be pasted into this program or The copy tool in the toolbar copies the entire table.
If you are at the solution stage, the copying will be for the table that is active. Copy Special will copy the entire table but enable you to limit the number of decimals that are copied. Paste Paste is used to paste in the current contents of the clipboard.
Thus, it is possible to copy a column to a different column beginning in a different row. This could be done to create a diagonal. It is not possible to paste into a solution table, although, as indicated previously, it is possible to copy from a solution table.
Paste from myomlab Paste from myomlab is available in the File menu but is easier to use from either the toolbar or by right-clicking on the data table after copying data from myomlab. Note: Right clicking on any table will bring up Copy options and if the table is the data table it will also bring up the insert and delete options. View View has several options that enable you to customize the appearance of the screen.
The Toolbars menu contains two options. The toolbar can be customized as can most Windows toolbars or the toolbar can be reset to its original look. The Status Bar display can be toggled on or off. Full Screen on or off. It is easier to use the zoom tool on the standard toolbar. Colors can be set to Monochrome black and white or from this state to their Original Colors.
This formerly was very useful when overhead devices displayed much better in monochrome than in color. Today, projectors are so powerful that monochrome is generally not required. The QM for Windows Version 4 app will be found automatically.
Notice that after you click QM for Windows Version 4 in the list of apps, the following data about the program is available to you: Safety rating in the lower left corner. The star rating tells you the opinion other users have about QM for Windows Version 4 , from "Highly recommended" to "Very dangerous".
Opinions by other users - Press the Read reviews button. Technical information about the program you are about to uninstall, by pressing the Properties button. LOG 7. Press the Uninstall button. A confirmation dialog will appear. Confirm the uninstall by clicking Uninstall. Press Next to go ahead with the cleanup.
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