Turn on suggestions

Auto-suggest helps you quickly narrow down your search results by suggesting possible matches as you type.

Showing results for

- Navigation
- Tecnomatix
- Forums
- Blogs
- Knowledge Bases
- Groups

- Siemens PLM Community
- Tecnomatix
- Plant Simulation
- Determination warm up period, run length, number o...

Options

- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 08:24 AM

the different products I would create randomly (calculate the rate for each product), quantity by changing the interval of the source, and of cource non blocking

Steffen Bangsowfreelance simulation specialist web: www.bangsow.eu mail: steffen@bangsow.net |

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 08:31 AM

You now have a created a cyclic simulation model (weekly cycle). Therefore you introduce some bias that you need to take into account when you set the run-length (weekends, with no production).

For very long runs the effect will diminish, but when the run-length is only a few weeks long, the weekend losses do have a statistically significant effect. To avoid this, make sure the length is a multiple of 7 days.

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 09:12 AM

Dear @Steffen_B, @Nomden,

Thanks for your reply!

Do you agree with the following calculation in terms of the quantity of products?

Let`s assume that for a certain product there are 120 orders per year. The system is operational for 5 days a week for 5.9 hours a day (+-1500 hours a year). This are (5/7)*365 = 261 days per year. Hence, 120/261 = 0.46 products will arrive per day from this product type. I repeat this calculation for the complete product scope of 76 products and sum up the total amount of products per day. Assume this is 8.86. Then, 5.9 (working hours per day) / 8.86 = 0.67 hours = 40 minutes. Hence, I will set the negative exponential interval with a mean of 40 minutes and products will be selected based on the portion calculated above (0.46 for the example product). Lastly, the "blocking" must be cleared (deactivated).

Furthermore, @nomdem I will set the run length on a multiple of 7 days.

Many thanks in advance!!

Kind regards.

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 09:33 AM

theoretically: yes

from a practically point of view, it is not secure enough

if you only have 120 orders per year and you will distribute the parts randomly, then you need I guess 100-500 years simulation time to get a statistical distribution around 120

a better way is a statistical method "pull without replacement" (in German ziehen ohne zurücklegen);

here you create an anonymous MU and you dice a product (e.g. with z_dEmp --> see help). After producing one part, you degrease the quantity of this part in the production plan and calculate a new empirical distribution for the next call until the production plan is empty --> stop simulation

Steffen Bangsowfreelance simulation specialist web: www.bangsow.eu mail: steffen@bangsow.net |

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 09:43 AM - edited 02-06-2019 09:44 AM

The calculation looks plausible to me, if you want just a randomized mix.

I did notice that you filled in some parameters for the set-up behavior, but no set-up times. This may be on purpose, I just could not help to notice.

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 09:43 AM

Dear @Steffen_B,

Thanks for your reply! In principle, it works since I obtain somewhat the throughput that I expected after running the model for 1 year for instance.

However, if this is nog secure enough, then I really would to implement your suggestion into my model. Could you check the current arrival distribution in my model with the table file? I am not common with "pull without replacement", so could you please provide an example or some recommendations on how I should adjust my source?

Many thanks in advance!!

Kind regards.

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 10:02 AM

How sure are you about the product ordering distribution?

Are they ordered totally independent from each other? Then you need many observations (excessively long runs do not make sense to me), as Steffen pointed out. But this could be the fact of life in your case.

Or is there some form of correlation? Then Steffen's method may have to be used. I would run some sensitivity-analysis on the product distribution anyway.

A hint on the frequencies: you can use absolute numbers, Product1: 120, etc. This can make life a bit easier...

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 10:09 AM

you can check it by yourself

--> drain -> type statistcs -> detailed statistics table

Steffen Bangsowfreelance simulation specialist web: www.bangsow.eu mail: steffen@bangsow.net |

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 10:10 AM

@Dear @Nomden ,

Thanks for your reply!

There is no correlation, so they are independent!

Concerning the set-up without times, this is indeed on purpose.

Could you please elaborate more on what you mean with your last sentence concerning absolute numbers? Can you provide an example?

Many thanks in advance!!

Kind regard.

Re: Determination warm up period, run length, number of replications

- Mark as New
- Bookmark
- Subscribe
- Subscribe to RSS Feed
- Permalink
- Email to a Friend
- Report Inappropriate Content

02-06-2019 10:20 AM

Of course, I guess it is simpler htan you expected...

Follow Siemens PLM Software

© 2019 Siemens Product Lifecycle Management Software Inc