◢ ◤ Inventory supply chain problems within the enterprise-oriented analysis

In the 1990 of the 20th century a series of abroad advanced supply chain inventory management techniques, such as AFR, JMI, VMI and CPFR etc. Characteristics of China's domestic enterprises on how to study the implementation of advanced management technologies, such as VMI and CPFR implementing trust mechanisms and related supply chain research. Meanwhile, around supply chain inventory control at home and abroad and also carried out extensive research for the optimization, inventory costs involved in research on supply chain performance, supply chain research, different characteristics of inventory control strategy study on mathematical model and its solution, inventory research and inventory optimization study using simulation methods. However, these advanced management techniques and optimization technique in enterprise in China's transplant was not successful, and the majority of inventory control in supply chain in manufacturing companies is still fraught with problems. From the angle of the actual operation of enterprises, business inventory management and inventory control behaviors were typical case analysis, is designed to hold in inventory control in manufacturing enterprises in China focused on common problems and to find measures to solve the problem, improving inventory control and level of technology.

analysis of 12 cases of typical enterprise

choose an automotive plastic parts supplier (business 1) and a pharmaceutical company (company 2) as a typical case, former representative in the upstream stages of the supply chain of enterprise, and later represented in downstream stages of a business. Meanwhile, the two enterprises and large differences in features, representing different levels of model and basic management of enterprises.

for manufacturing companies, but different roles, different interests and performance in supply chain inventory control problem there are different. Two problems can be divided into external-oriented (or supply chain) with two levels and be discussed within the enterprise.

2 external-oriented analysis of supply chain inventory problems

in external-oriented problems, most notably the following:

first, poor supply chain management model of a serious impact on the supplier and manufacturer relationships between efficiency and cooperation. Inventory management of supply chain cooperation are often subject to the short-term interests of powerful enterprises, most of the supply chain continues to take the form of users to manage their own inventory, supplier is obtained by expatriate rough month demand forecast, provisional urgent orders and monthly consumption and inventory information, it has not been conducting research on joint replenishment, there is no need to share the information. Result, the bullwhip effect, greatly increased the level of inventory throughout the supply chain.

then squeeze each other very prominent among supply chain members. Including extrusion downstream node upstream node, strong vulnerable and similar nodes nodes extrusion extrusion and so on. The squeeze as price, cost, and risk of extrusion, resulting in profits and squeezing of the living space. This squeezing not only weak enterprises are hit, also have a negative impact on the supply chain usually result in increased overall costs of supply chain, affecting the competitiveness of the supply chain.

third is a serious crisis of confidence between members of a supply chain. Include downstream, upstream and downstream nodes do not trust an upstream node node trust wishes to be symmetric, trust easy destruction and vicious cycle and the trust mechanism of supply chain without a specification. Inventory control in supply chain operations, there is no standardized mechanism to constrain the supply chain of enterprise should be in accordance with the standards for supply chain to provide the information they should provide, to assist adjacent businesses to achieve smooth and efficient logistics interface.

external logistics resource use is not enough, lagging seriously impact on the ability of logistics enterprise inventory control capability is also very prominent. Now many companies are outsourcing, but the long procurement lead time period is the most prominent problem, if the full use of external resources can greatly shorten procurement lead times.

3 inventory analysis of enterprise-oriented supply chain

facing internal problems, the discussion has highlighted three main points: one is the internal logistics decision contrary to the basic idea of inventory control; the second is the internal performance evaluation and incentive system hinder rationalization of enterprise logistics operation and control; the third is behind quite inventory control technology of internal conditions and the environment.

studies have found that enterprise inventory control lies at the root of enterprises in production planning, demand planning, procurement and other logistics decision-making process constitutes a breach of the inventory (or the whole logistics) control. Figure 1 is a case 1 of the decision-making process, at present, China's role played many suppliers, manufacturers have adopted this way of production/inventory management decision. Enterprise logistics mainly by manufacturers months orders pull on both inventory management controls necessary to respond to the manufacturer's demand for timely, urgent replenishment. Such companies tend to average inventory levels, frequent emergency replenishment, even making it difficult for enterprises to take and respond to. Figure 2 is a case 2 of the decision-making process, this model is more end-product manufacturers. Such companies tend to aim for production, to produce scrolling needs to scroll through demand and supply price materials procurement, product sales performance. This result in passive storage warehouse operations, essentially no inventory control.  

enterprise performance evaluation and incentive effects on Enterprise inventory control more covert, but should be given adequate attention. Enterprises in the typical phenomenon could explain the problem. For example, the production sector in the original plans decide for excess production, apply to the materials library materials, because the original plan did not plan for this part of the supply, so on the surface, raw material shortage occurs. Warehouse Department Notice to the supply Department, the supply sector organizations purchasing, supply procurement cycle is said to be for nearly two months, must complete the supply difficulties involved. Therefore, supply applications allow to purchase large quantities of items to store spare. The result, natural increase in inventory level, logistics flow slows down, inventory and related costs. Analysis of the cause of this phenomenon, find such a causal relationship because overfulfilling is a bonus, at least not punished, so production overfulfilling the behavior occurs. But on the surface he appears out of stock, supply in the examination is to be punished, for their own interests, supply always tries to increase procurement capacity within the procurement funds allow, to warehousing Department done, and at the time of purchase lead time gives plenty of scope, so they are rightly higher assessments or to less punishment. Warehousing sector because of objective reasons such as location, into a large number of stock management difficulties, also affecting the results of the assessment, so storage sector cannot meet the requests in a hurry, and receive a large number of procurement of materials. This chaotic behavior is essentially because of problems with enterprises in the logistics management, but the important thing is the performance evaluation and incentive mechanisms added to management problems.  

Enterprise inventory control technologies is fully aware of the conditions, but it's hard to change that seems to. No basic management of enterprises, no inventory control procurement mechanism, control on key material depends entirely on empirical decision without information systems, there is no effective means of sharing information, not to inventory management software and decision support techniques and strategies to optimize inventory control technology. Research found that in many manufacturing companies in China are in this situation, these types of businesses are profitable, typically rely on the mainly in some exclusive technologies, special policies to protect and a growth in the market. In the long run, this is a risky business.

4 inventory for enterprise internal control measures

solve enterprise-oriented supply chain management inventory control needs for enterprise external and internal-oriented relevant measures in the two aspects, namely, which require more in-depth research. For most manufacturing companies, from their own, and had some achievements, and can affect the supply chain upstream and downstream enterprises, cooperative attitude, is action on issues from within the enterprise.

first, the enterprise's priority is to change the enterprise logistics decision making mechanisms. Logistics decision-making mechanisms essentially determines the company's production and operations management and logistics operational performance and the causal relationship between inventory status. Figure 3 show a logistics process control mechanism. Under the mechanism, raw material and finished product inventory control and production plan and purchasing plan, is a relatively independent and active, that is, according to procurement and inventory control services for the production and control of finished goods inventory planning. This shift in decision-making mechanism key to different functions of duties and rights of the redesign, to form the new decision flow between different departments.

to facilitate the implementation of this mechanism, you need to have an effective performance evaluation and supervision and evaluation mechanism to motivate. Logistics performance evaluation index system of enterprises should formulate a reasonable and scientific research gives reasonable performance evaluation standards of the enterprise, could we understand their own strengths and weaknesses in logistics operation. Are able to objectively evaluate their performance based on the assessment of departments and posts and total performance-related and fully reflected in the evaluation objective causal relationship between position and performance, rather than the surface of the work, to encourage the efforts of departments and posts for overall performance of enterprises, effectively stifling deviate from the overall interests of the various departments. Performance evaluation and appraisal index system of the set was also a focus of the current study, may wish to consider completely changed the existing mechanisms at the following levels:

• the use of advanced technology to the enterprise to achieve the best possible performance for scientific assessment, or the most companies used the same types of data as a benchmark, benchmark, to evaluate actual performance levels of play;

• in Department of examination system based on logistics process of appraisal system Rewards is subject to efficiency of logistics processes in cooperation between assignment;

• establish a rigorous, standardized logistics management standards to standards for constraint, comparative assessment and post implementation in all sectors, make the assessment objective reflect Department and logistics control of causality;

in addition, speed up the Informationization construction of enterprises, the use of advanced information technologies and decision support technology, ensure the smooth implementation and sharing of information, uncertainty factors of different strategies can be a reliable assessment, forecasting and analysis, in order to achieve scientific decision-making, control information, policies, dynamic inventory control problems is in technology.

5 emulation technology support for inventory control in supply chain

simulation is an effective analysis for uncertain discrete-event systems, simulation can be used as a corporate support for inventory control of supply chain management technology. Simulation has been used in many existing inventory control in the related areas of research, such as the influence of information sharing on supply chain performance, supply chain reference model of discrete-continuous model and analysis of discrete model for study on the effects of supply chain inventory levels, adaptability study on multi-stage inventory model, and so on. Italy a cattle and dairy companies are also using simulation technology to study their production/inventory system, optimize milk purchasing and inventory control for two kinds of cheese products. Inventory control strategy on certain characteristics simulation method of study also started borrowing. Simulation technology is increasingly being applied to the areas of supply chain inventory management.

author in case 1 of the inventory system in supply chain logistics decision making mechanism, inventory control and inventory control strategy analysis and optimization on the use of simulation technology in the study. The study represents Petri nets (STPNs) method and simulation, case 1 involves three car manufacturers supply chain inventory system modeling and simulation, analysis and optimization of spare parts inventory replenishment strategies. Studies show that simulation technology in supply chain inventory management has a good prospect, can become oriented to supply chain management decision support technology for effective inventory control.