The scheduling of the elevator is really confusing, why wait for more than ten minutes, this thing just doesn't stop? The more this lazy thing appears in our lives, the more I start to wonder how it works.
Today we are going to talk about how the elevator comes and goes, so that you can reduce the need for lateness to work.
Getting up, going to work, and going home have formed the three points and lines of working life in our cities.
The clock-in time at work is like a talisman, urging me to fight all to bless my salary.
But often when we overcome warm quilts, traffic jams, crowded subways, and get to the downstairs of the company.
There was also a moat in front of me. That's right, that's the elevator that never knows in **, Schrödinger.
No one would really climb such a high floor with their feet, and believe me, you may not even find the stairs in **.
But sometimes, the scheduling of the elevator is really confusing, why wait for more than ten minutes, this thing just doesn't stop?
The more this lazy thing appears in our lives, the more I start to wonder how it works.
Today we are going to talk about how the elevator comes and goes, so that you can be less late for work.
Analysis of individual elevator algorithms
What should you do if you were asked to design and design an elevator to operate?
The most modest elevators often only need the simplest way to help dispatch.
Leave those tedious situations aside.
Just let the elevator cycle from the ground floor to the top floor so that everyone can be picked up by the elevator.
However, although this method is "fair", it is not very efficient, after all, the elevator is running when no one is around, and many times it will waste time to run empty.
Therefore, if you want to make the elevator run faster, you have to take into account the purpose of the user.
Let's assume that every time we press the elevator, the current elevator will be summoned to come and we will be taken to our destination, so that this is a purpose.
After completing one purpose, the elevator waits for the next purpose, and then solves it?
Does it work? It works.
Is it easy to use? It's not easy to use.
Obviously, there is a big problem with this first-come, first-served method of serving.
Once the peak period is encountered, too many visits may crowd this elevator.
For example, when you get off work, if everyone on the 7th, 8th, 12th, and 19th floors has to go down, but this student on the 7th floor is the last to press the elevator.
The elevator will shuttle in front of the 7th floor several times until all the people above it are delivered, and then it will respond to the needs of the 7th floor.
That's the real end of the work press a second, an extra hour to wait. So, how can you improve the efficiency of the elevator?
If our elevator is running, we will list the next elevator stop needs into a **, and the task is close to my current position, then I will deal with it first.
For example, if you go downstairs at the same time, you can take people away from top to bottom when you pass by the 7th floor for the first time.
This shortest path-first algorithm, while seemingly efficient, can also help us move a large number of people to the elevator in a short period of time.
However, this efficient method of operation looks very high, but it still has fatal flaws.
That is, there will be a situation where people's needs are not responded, and sometimes after pressing for a long time, the elevator will not come at all.
For example, in a company, there is a lot of people coming and going between the 17th and 21st floors, and there are people going up and down almost all the time.
At this time, if someone wants to go up from the first floor, the elevator will go back and forth between the 17th and 21st floors every time because it is too far away from the first floor and they are "looking for the nearest service".
The elevator on the first floor was abandoned because it was too far away, and it would not come down until they were done with their work, which might be dark.
And this kind of scheduling will also make the elevator keep going back, and the experience may not be good for the people standing inside.
And this kind of scheduling is still a toss to sit up.
For example, I obviously want to go online from the 17th floor to the 21st floor, but because there is a guy upstairs who wants to go from the 18th floor to the 16th floor, I have to accompany him down again, and my head will be dizzy.
Therefore, the above three methods are not reasonable scheduling methods.
And if these methods are combined in the future, it is actually a common method for single elevator scheduling now.
Also known as the look algorithm, it may sound familiar to readers who are familiar with computer technology.
Under its scheduling, the elevator is still moving up and down, but the scope of movement is no longer from the lowest floor to the top floor, which wastes resources at the beginning.
Instead, it only runs to the top or bottom of each request, and the middle door opening and closing tasks are handled together, which is simply a sentence: "Forward and reverse are not connected".
Wait until it reaches the top of the request, then turn it down, and in the same way process these manned requests, and if no one summons it, it will stop to save energy.
In fact, making the elevator run more fair and reasonable scheduling is essentially a problem of sequencing and efficiency optimization.
These single-ladder scheduling algorithms are actually variations of the head scheduling algorithm of our mechanical hard disks in the early years.
Especially in conventional mechanical disks, the efficiency of head movement is crucial.
Similar to the elevator algorithm, the hard disk optimization algorithm tries to reduce the distance traveled by the head, thereby reducing the seek time and improving the efficiency of data reading and writing.
Although HDD is not used much at present, perhaps in the future, these generalizations and efficiency improvements can lead to some unexpected uses in new industries.
Elevator group control algorithm analysis.
In our life, as we have higher and higher requirements for the space complexity of floor time design, the traditional single elevator and single control are no longer enough to meet everyone's requirements.
The principle of double ladder scheduling is not complicated, and the core is still this "forward and reverse connection".
The only difference is in the choice of which elevator to pick up the person.
This is the nearest choice, and the nearest elevator will run over to help pick people up.
Of course, as the buildings we build become more and more complex, the scheduling principle of elevators will become more cumbersome.
The difficulty is not in the technology, but in the service.
After all, hotels, offices, and lodging areas, and different buildings will have different scheduling needs.
Compared with scheduling, how to meet the demand for quantity is more important.
The problem of elevator scheduling has become a difficult problem of information collection and solution.
For example, consider how many users are waiting on each floor, whether the people inside the elevator are full, and so on.
After the popularization of computers and electronic control systems, the way of elevator group control to deal with problems has gradually diversified.
Different traffic in the same scenario can also intelligently adopt different scheduling modes. For example, in some apartments, in order to make it easier for everyone to go downstairs during daily hours, an elevator will be stationed in the middle of the floor, and an elevator will stop at the bottom of the apartment. This allows for faster pick-up.
Even in different application scenarios, the design of the elevator itself has different specification schemes.
For example, in our country's "Unified Standard for Civil Building Design", it is mentioned that the number of elevators in high-rise public buildings and high-rise dormitory buildings should not be less than 2, and the number of elevators in residential buildings with 12 floors and more than 12 floors should not be less than 2.
It can also be seen in the "Residential Design Code" that elevators must be designed for residential buildings with seven floors or more.
So, now we know why many old residential buildings tend to have only six floors.
When designing elevators for hotels or office buildings, different "service standards" will be involved.
For example, when some five-star hotels design elevators, they consider how to allow guests to achieve the elevator within one minute, so as to reduce their anxiety of waiting.
Office buildings, on the other hand, are more complex, and Peter Research, a company specializing in elevator scheduling, has done a modeling analysis for it.
During the one-hour rush hour, about 85% of the people are coming into the building to work, 10% are going out, and the remaining 5% are moving between floors.
And during this peak period, the amount of ** also gradually rises in the first half hour until half of the time has passed. During the 5 minutes when people are at their most crowded, the elevator takes on 12% of the entire morning rush hour.
Suppose there are 2,000 people commuting to and from an office at the same time, which means that the design specification of the elevator needs to consider that it can send 240 people away in 5 minutes, which is equivalent to transporting 48 people in one minute.
At lunchtime, the model is slightly different, with people going upstairs and downstairs going back and forth, each accounting for about 45%. And the amount of ** also shows two peaks over time, which is in line with everyone's intuition when they go out to eat and come back to work.
With different model scheduling tests, elevators also need to be designed with different working modes to pick up and drop off guests.
In fact, in the face of such a large load as an office building, many companies will adopt the legendary "destination dispatch system".
That is, when we enter the elevator, we don't manually call the elevator down by floor, and then enter the floor we want to go to. Instead, before entering the elevator, you tell the system where you want to go.
In this way, the elevator dispatching system can arrange people who go to the floor to an elevator, so that the elevator has fewer stops and faster round-trip speed, so as to achieve "efficient work".
In fact, the group control scheduling of elevators is actually a problem that is constantly improving.
In **, you can also see that everyone is trying to realize the scheduling of elevator clusters through various methods such as expert network, dynamic search, multi-agent, reinforcement learning, etc. In engineering, it is also possible to see the use of partition elevator technology in high-rise buildings to shine.
Perhaps until the advent of a full-fledged air traffic system, we may have to endure waiting for an elevator to go to work.
Written by: Yuluo Silent Editor: Huan Yan.
*, Data**:
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2 AI Talk: Elevator Scheduling Operation Logic3 Elevator Integrated Destination Layer Group Control System User Manual4 Simple Analysis of Dual Elevator Elevator Scheduling Algorithm5 How to Design an Elevator System for a 300-Story Skyscraper? —Hu Ruifeng6 Ding B, Zhang Y M, Peng X Y, et ala hybrid approach for the analysis and prediction of elevator passenger flow in an office building [j]. automation in construction, 2013,35 : 69-78.7the application of simulation to traffic design and dispatcher testing 8. Research on elevator dynamic scheduling strategy based on reinforcement learning algorithm[D].Tianjin:Tianjin University, 2005 9 Liu Dong. Research on traffic pattern recognition and dispatching control of group-controlled elevators[D]Shenyang Jianzhu University, 2014
*The content represents the author's views only.
It does not represent the position of the Institute of Physics of the Chinese Academy of Sciences.
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*: Negative. Editor: Yue Yue.