In order to research on the impact of suppliers time on invalid-iteration,A concept of knowledge Accumulation curve is introduced firstly,then a model on involvement time of suppliers is established based on information dependent of tasks and innovation of tasks.

A concept of "invalid-iteration" for product development is introduced and its causes are discussed in this paper.

Based on the analysis of risks from invalid-iteration,some measures to avoid risks are proposed to enhance their cooperation among virtual enterprises(VE),optimize their flows of product development and perfect their information system.

In any school exists the phenomena of invalid management, which means that school leaders can not obtain the expected goals in the use of resources or the orientation of the goals is wrong.

The concepts of unauthorized agency and unauthorized agency contract are reviewed,and the validity of unauthorized agency contract stipulated in the clause 48 of the Contract Law of PRC is probed.

During the process of practicing civil laws , some civil law behaviors can only form unauthorized agency, for the lack of procuration, although they can be called attorneyship, for the possession of the superficial features of attorneyship.

If the relative party was in good faith and innocent when contracting,he may claim the contract to be valid under apparent a-gency and the lender is liable,or choose unauthorized agency and the lender and borrower are related liable for the damages to his reliance interest.

Ownership, Agency Cost and Agency Efficiency;

The Research on Agency Chains and Agency Efficiency of the Government Investment Project;

The lack of the organizational effectiveness of Baijia Group lies in the facts that the Organization can t adapt itself to the environment effectively and that its operative efficiency (technical efficiency and agency efficiency) is quite low.