scott wrote:
>> Grocery stores have facilities for storing enough tea to sink a ship.
> 
> Except they don't, they have the absolute minimum storage to keep the 
> shops in-stock.  Any additional storage is wasted money, not just 
> because of the building costs, but because the product could be cash 
> instead, earning money in the bank.  Ever heard of Just In Time business?
> 
> Where I used to work, even if a truck turned up an hour early to deliver 
> stuff (which they knew they couldn't, they usually waited in the street) 
> it sometimes wouldn't even be possible to unload because there would be 
> no empty slots in the warehouse.

What a remarkably inefficient way to do business...

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>> Except they don't, they have the absolute minimum storage to keep the 
>> shops in-stock.  Any additional storage is wasted money, not just because 
>> of the building costs, but because the product could be cash instead, 
>> earning money in the bank.  Ever heard of Just In Time business?
>>
>> Where I used to work, even if a truck turned up an hour early to deliver 
>> stuff (which they knew they couldn't, they usually waited in the street) 
>> it sometimes wouldn't even be possible to unload because there would be 
>> no empty slots in the warehouse.
>
> What a remarkably inefficient way to do business...

You have a more profitable idea?  Specifying exact delivery times, to within 
+/- 15 minutes is quite common for large factories.  Do you have any idea 
how much raw material a large manufacturing site can get through?  Where I 
worked there were *always* about 3 or 4 trucks delivering material, and 
10-20 being filled simulatenously with finished goods.  It is simply too 
expensive to store enough material and arrange the logistics if you allow 
deliveries to turn up at any time during the day.

Even at my small local supermarket they seem to know exactly when the 
deliveries will be made (they put out cones around the area the truck has to 
reverse).

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>> What a remarkably inefficient way to do business...
> 
> You have a more profitable idea?  Specifying exact delivery times, to 
> within +/- 15 minutes is quite common for large factories.  Do you have 
> any idea how much raw material a large manufacturing site can get 
> through?  Where I worked there were *always* about 3 or 4 trucks 
> delivering material, and 10-20 being filled simulatenously with finished 
> goods.  It is simply too expensive to store enough material and arrange 
> the logistics if you allow deliveries to turn up at any time during the 
> day.
> 
> Even at my small local supermarket they seem to know exactly when the 
> deliveries will be made (they put out cones around the area the truck 
> has to reverse).

This doesn't seem to tally with my experience at all. Most shops will 
tell you an item is out of stock and they typically have *no idea* when 
it will be back in stock. Or they promise it will be back in on date X, 
and it isn't, and then they promise date Y, and it doesn't, and then 
they say a delivery is coming in on date Z, but then they say it hasn't 
come in... You start to wonder how they manage to do business at all!

But anyway, while I can imagine a factory being able to predict how much 
raw materials they need on a given day, predicting exactly how many tins 
of baked beans you're going to sell today is obviously impossible. You 
can estimate it of course, but you cannot possibly predict it exactly. 
And if your prediction is too low, you have an empty shelf. This, 
presumably, is commercial suicide.

Similarly, according to your scheme, if one delivery truck gets a flat 
tire, or makes a wrong turn, or drives to the wrong store, or makes any 
one of a million other simple mistakes, empty shelves result. Surely 
this is no way to do business.

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> This doesn't seem to tally with my experience at all. Most shops will tell 
> you an item is out of stock and they typically have *no idea* when it will 
> be back in stock.

Most shops are no way near as organised as the likes of Tescos or any large 
manufacturing company.  And by no coincidence, they don't make as profit 
either...

> Or they promise it will be back in on date X, and it isn't, and then they 
> promise date Y, and it doesn't, and then they say a delivery is coming in 
> on date Z, but then they say it hasn't come in... You start to wonder how 
> they manage to do business at all!

Exactly.  But ask the store manager of Tescos when the next pallet of beans 
will be delivered and he will be able to tell you to the nearest 15 minutes.

> But anyway, while I can imagine a factory being able to predict how much 
> raw materials they need on a given day, predicting exactly how many tins 
> of baked beans you're going to sell today is obviously impossible.

Based on your sales of the previous days you can easily get an accurate 
prediction with confidence levels, eg 500 tins +/- 50 with 99% confidence. 
So you order 550 tins and you're 99% sure you'll be ok.  Sure, you'll have 
an average of 50 tins left over, but depending on that figure you can modify 
the quantity of the next order.  The optimising part is to keep the number 
of "left over" tins that you have to store to a minimum whilst ensuring the 
risk of running out of stock is close to zero.  You need to give a "cost" to 
the running out of stock scenario, and calculate what is the optimum.  Do 
not underestimate how much maths and stats is involved :-)

> Similarly, according to your scheme, if one delivery truck gets a flat 
> tire, or makes a wrong turn, or drives to the wrong store, or makes any 
> one of a million other simple mistakes, empty shelves result. Surely this 
> is no way to do business.

What is the chance of any of those things happening?  You estimate an actual 
number (eg by counting the number of flat tyres or times when the truck went 
to the wrong store in the past) and work out how much it is likely to cost 
you.  And then you see it is less than building and running a bigger 
warehouse (well I assume you do, as this is how most large companies work).

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Invisible wrote:
> Similarly, according to your scheme, if one delivery truck gets a flat 
> tire, or makes a wrong turn, or drives to the wrong store, or makes any 
> one of a million other simple mistakes, empty shelves result. Surely 
> this is no way to do business.

Tell that to the people delivering concrete, where being a half hour late 
means that the concrete is hardened in the truck and the building you're 
pouring now needs a bunch of work so the new concrete will stick to the old.

-- 
   Darren New, San Diego CA, USA (PST)
   There's no CD like OCD, there's no CD I knoooow!

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>> Surely this is no way to do business.
> 
> Tell that to the people delivering concrete, where being a half hour 
> late means that the concrete is hardened in the truck and the building 
> you're pouring now needs a bunch of work so the new concrete will stick 
> to the old.

Is it possible for concrete to set while it's still in motion?

But sure, that still sounds like a pretty expensive problem...

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Invisible <voi### [at] devnull> wrote:
> Is it possible for concrete to set while it's still in motion?

  I would guess that water cannot remain there for infinity, so the
concrete is going to dry eventually. If it's constantly being disturbed,
I assume what you get is a bunch of concrete gravel.

-- 
                                                          - Warp

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Warp wrote:
> Invisible <voi### [at] devnull> wrote:
>> Is it possible for concrete to set while it's still in motion?
> 
>   I would guess that water cannot remain there for infinity, so the
> concrete is going to dry eventually. If it's constantly being disturbed,
> I assume what you get is a bunch of concrete gravel.

Mmm, seems plausible.

FWIW, as I understand it, it's not the water as such. The setting of 
concrete involves a chemical reaction rather than the mere removal of 
the water.

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Invisible <voi### [at] devnull> wrote:
> FWIW, as I understand it, it's not the water as such. The setting of 
> concrete involves a chemical reaction rather than the mere removal of 
> the water.

  I don't know if disturbing the concrete while it's drying messes up
with those reactions, but if it does, you would probably eventually get
some kind of dust or gravel.

-- 
                                                          - Warp

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Warp wrote:

>   I don't know if disturbing the concrete while it's drying messes up
> with those reactions, but if it does, you would probably eventually get
> some kind of dust or gravel.
> 

You wind up with a cement truck that you'll have to clean out with a 
jackhammer.

-- 
~Mike

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