What Is Continuous Optimization?
Time optimization refers to the initial scheme that continuously improves the network plan by using the time difference under the established conditions, and seeks the optimal scheme according to the shortest time index. The basic method is to continuously shorten the duration of the critical route to the minimum: equal to or lower than the specified time. To this end, it is necessary to use the time difference to find the key work that can shorten the duration and continuously adjust the key routes in the network graph until the optimal or satisfactory solution is obtained. Time optimization is the most basic and important task in network planning optimization. Because the calculation of the optimization process is generally cumbersome, it is usually performed by an electronic computer. [1]
- The optimization of the network plan is the process of constantly checking, evaluating, adjusting and improving the network plan according to a certain goal under the established constraints to find the optimal network plan. There are three types of network plan optimization: time optimization, cost optimization, and resource optimization.
- Resource optimization is to change the start time of the work so that the distribution of resources according to time meets the optimization goal. Resource optimization is divided into two types: "limited resources, shortest construction period" optimization and "fixed construction period, resource balance" optimization.
- The cost optimization is also called the cost optimization of the construction period. Refers to the process of seeking the lowest total cost of the project or the process of planning the lowest cost according to the required period.
- Duration optimization is the process of compressing the calculation duration to achieve the required duration goal, or to minimize the duration under certain constraints. Optimization of the construction period
- 1. In the optimization process, we must pay attention that we cannot compress critical work into non-critical work, but critical work can be turned into non-critical work without compression.
- 2. In the optimization process, when multiple
- The duration optimization is to meet the requirements of the duration by compressing the duration of key work (ie increasing labor or mechanical equipment and shortening the duration of work). The steps of duration optimization are as follows [4]
- Figure 1 of the network plan for a certain project is shown below. The compression rate, normal duration, and minimum time of each job are marked on the arrow line. The project requires completion within 26 days. Try to adjust the network plan and calculate the cost of rush work. .
- figure 1
- Solution: The original network plan calculates the construction period as 34 days. The key work is shown in the red line in Figure 2. It is compressed 8 days as required.
- figure 2
- First calculation: The key work with the lowest rush rate is shortened by 2d, is shortened by 2d, is shortened by 2d, and the construction period is shortened by 6d. The key lines become two: , . The total construction period is 28d.
- The rush costs are: 150 * 2 + 120 * 2 + 90 * 2 = 720 yuan.
- The second calculation: shorten the key work by 1d, by 1d, and by 2d, and shorten the construction period by 2d. The key lines become two: , . The total construction period is 26d.
- The cost of rush work is: 200 * 1 + 150 * 1 + 140 * 2 = 630 yuan. The total cost of rush work is 720 + 630 = 1350 yuan.
- The adjusted network plan calculation period is 26 days, as shown in Figure 3.