DISPOSICIÓN DEROGATORIA
C) OPERACIONES DE SERVICIO
3.1 Strategies aiming at the unreasonable stock
The flexibility and smartness of enterprise production decide that the rhythm of the stock demand is fluctuant, and the price fluctuation is one of the important reasons inducing that change. We put forward the corresponding strategies from two aspects.
3.1.1 Strategies of stock forecast based on the method of Monte Carlo
Because the demand of raw material has some certain randomicity, so we can implement the statistics method to compute in and out depository of the raw material in recent 3-5 years and inventory surplus of each month and each year, and get the corresponding probability distribution (if the distribution is not obvious, we can consider the equal distribution of the maximal value and the minimal value), establish the probability model combining with once stock cost, storage cost of single goods and the cost of absent goods, then educe the minimal value of the cost using the random simulation method of Monte Carlo. And we will give the simple example as the following.
Hypothesis of the model:
First, in and out depository and the inventory surplus submit to the corresponding equal distribution of the maximal value and the minimal value.
Second, the order times of each year are fixed.
Third, the cost of one piece of absent goods can be computed by means of statistics according to the past years’ data. Parameters:
C1: order charge of every time.
C2: storage charge of every piece of goods.
C3: loss of single absent goods.
qmax: maximal value of out depository in the statistical accounting interval.
qmin: minimal value of out depository in the statistical accounting interval.
pmax: maximal value of in depository in the statistical accounting interval.
pmin: minimal value of in depository in the statistical accounting interval.
q: out depository of goods. p: in depository of goods. M: times of order. ⎩ ⎨ ⎧ = goods of absence no 0 goods of absence 1 x Variables:
Q: the amount of order Establishment of the model: From the hypothesis, we can get: (1)q=U1
(
qmax, qmin)
,p=U2(
pmax, pmin)
(2) Because the costs of order are fixed and don’t change with the amount of the order, to simplify the model, we don’t consider the charge of this part. So we have
(
C Q p q x C q p Q x)
y=min 2*( + − )* + 3*( − − )* . Solution of the model:
The random number will be produced according to the distribution function in the probability model. When producing a random number every time, we can get a value from the object function through the corresponding data, then compare the value with the last object value, if the new value is better, it will replace the original vale, whereas it is replaced. After many times circulation, we can get the minimal value, and the concrete flow is seen in Figure 3. 3.1.2 Strategies of price fluctuation based on strategic alliance of enterprises
Enterprise should establish the strategic allied connection among enterprises, and in numerous suppliers, enterprise should choose several ones to become its strategic partners and establish the long-term cooperation with them. To enterprise, the suppliers have not been the aim to mine profit, that is to say, enterprise would not obtain the material of the land-value through the argy-bargy with the suppliers and they are a community with benefits.
(1) The suppliers should sign the supply contract, and ensure the supply amount to the enterprise in the condition of absence of raw material. Thus, enterprise can reduce the costs induced by the safe inventory.
(2) Enterprise should help suppliers improve the products, and implement necessary supervision in the process of production. In this way, enterprise can not only enhance the quality of the raw material purchased, but also can excuse the charges in the process of stock and check at the same time.
3.2 Strategies aiming at improper market forecast
The degree that enterprise put in various product markets and the veracity of demand information needed by the consumers have influences to the confirmation of stock of manufacture enterprise in different extents, and influence the inventory costs. Aiming at these two main aspects, we put forward the corresponding strategies.
3.2.1 Forecast Strategies based on the theory of Markov chain
The demand of market always has some certain period, and the demand of this period is decided by the situation of the last period to large extent, which accords with the character of Markov chain, that is to have no aftereffect.
}
{
Xn is the Markov chain, and all possible values are recorded as estate spaceE={
x1,x2,x3,...}
. To random integer n and xi1,xi2,...,xin∈E , only the probability is bigger than zero,so
{
}
{
}
n n n n i n i n i n i i n x X x X x P X x X x X P +1 = +1| 1= 2,..., = = +1= +1 | = .Secondly, to random
x ,
ix
j, we haveP{
Xn+1=xj|Xn =xi}
=P{
Xm+1 =xj |Xm =xi}
. Pijis the transfer matrixand
( )
j ij n→∞p n =π
lim . Whatever the original estate is, if only the term is enough long, the probability of the estateX j
will be close toπ . j
Using this character, we can implement according to the following steps.
(1) Confirm the estate spaceX , for example taking three kinds such as car, truck and jeep, where n X represents the n
corresponding final probability.
(2) Get the transfer matrix Pij according to statistics from the former data. The concrete value should be confirmed
by the actuality.
(3) Bringing the data into the formulaXn∗P=Xn, we can obtain the value ofπ . Based on the result obtained, we can confirm the degree which production enterprise should put in.
3.2.2 Strategies based on incorporate strategy of clients
To obtain the demand information in the first time, enterprise should better contact consumers and fully know the consumers’ actual requirements. Associating with the higher and lower enterprises even the clients has become a sort of direction. In order to integrate such an aim into the whole supply chain, enterprise can adopt the strategy with
client integration.
In this strategy, the activity boundary of enterprise actually has enlarged from the enterprise itself to the larger range including consumers’ activity. The consumers have not been the exterior environment of enterprise, but the one component of the interior of the enterprise, which decides other composing and activity rules in the interior of enterprise such as arranging the consumer’s system according to the consumers’ requirements.
3.3 Strategies aiming at other factors
3.3.1 Establishing reasonable management system of depository and regulating the work of depository
Enterprise should bring the optimization of inventory system into the strategic layout of enterprise, establish special management department of depository and specific constitutions for each work, and chastise employees which disobey the constitutions.
At the same time, enterprise should strengthen the employees’ concepts to use equipments, and operate through the theory of positive aggrandizement (William, 2005). The method is to give those employees with higher work efficiency higher encouragements, and the premise is that these employees fully use the machine facility. In this way, in order to obtain the same rewards, other employees would increase the using degree usually, enhance the work efficiency in the depository and reduce the costs of labor work.
3.3.2 Establishing interior net of enterprise and strengthening communications among different departments
The enterprise information system or ERP can break the implosive information among departments to some extent. At the same time, because the information of order form can freely transfer in the interior of the organization, each department can establish its own objective and try to complete the order form. The selling department will translate the demand information into the order form and introduce to the production department, and then the latter will make the stock plan according to the order form and transfer the stock plan to the stock department which implements the stock. In this way, enterprise can translate the former functional organization structure into the organization “oriented by the consumers” to some extent.
4. Conclusions
The problem of inventory is always one of bottlenecks to restrict the development of enterprise. The higher inventory not only increases the occupancy of capital and the opportunity costs, but brings biggish enterprise revenue. But as viewed from another aspect that reflects the management of enterprise is improper and the system is not health. Starting with the actuality and problems of domestic enterprise inventory, this article finds out the key factors of higher inventory charge through the method of AHP, put forward some certain strategies combining with the relative theory, and offer the effective methods to analyze and improve the inventory problem for enterprise. References
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Figure 1. Change of Inventory Correlative Cost (Song, 2005)
Figure 2. Evaluation System of Key Factors
Figure 3. Simulation Computation by Monte Carlo Key Factors Information management Misplay of market forecast Depository management Capital
management management Market
Unreasonable stock Low using rate of
facility communicationsLacking in
Layout of depository
Produce random value
Compute using objective function
Get the function value
> Original value
Replace original function value Y
Table 1. Evaluation of significance
Evaluation of significance List of reasons Information
management Depository management Capital management Market management Misplay of market forecast 2 3 3 3 Unreasonable stock 3 3 2 2
Low using rate of
facility 1 3 2 1
Lacking in
communications 3 2 1 1
Layout of depository 1 2 2 1
Table 2. Comparison Matrix
Information management Depository management Capital management Market management Information management 1 3/5 3 1 Depository management 5/3 1 5 5/3 Capital management 1/3 1/5 1 1/3 Market management 1 3/5 3 1