关键词: 研发项目, 工期风险, 组织失效, 组织-任务网络, 耦合映象格子, 数值仿真

Abstract: In modern society, facing the complexity of technology, scarcity of resources and dynamic of market demand, it has become an effective mode for R&D project to form a network composed of many organizations. However, duration delay has been a common phenomenon in R&D project due to the great amount of sub-organizations and sub-tasks, high complexity of technology and uncertainty of external environment. Research studies also show that schedule problem has been one major cause of many risk events, and become a big challenge faced by managers. Therefore, it has become essential to analyze the schedule risk of R&D project under the context of networking R&D.According to literature review, many studies focus on analyzing the project schedule risk from the view of uncertain task by adopting Gannt Chart, Work Breakdown Structure, Critical Path Method, Program Evaluation and Review Technology, Graphical Evaluation and Review Technology, etc. However, few studies focus on the schedule risk from the organization failure that implements the project task. In fact, project organization is an important factor of schedule risk by allocating materials, human and budget that are necessary for project tasks. In this sense, the failure of a few organizations in R&D project will cause many neighboring organizations to fail, and then influences the durations of some tasks that are implemented by those organizations. Therefore, this paper adopts the coupled map lattice model to describe how the failure of some organization influences the duration of R&D project, which can provide a new insight into managing the schedule risk of R&D project under the context of networking.Firstly, this paper establishes the organization-task network model of R&D project, where organization network has the characteristics of scale-free network based on referring to the conclusions from many scholars, and task network includes three modes of sequence relationships of tasks, finally the execution relationships from organizations to tasks is established based on the organization network and task network.Secondly, based on the established organization-task network, this paper proposes the risk analysis model of R&D project with the organization failure as the factor of R&D project schedule risk. In this model, this paper adopts the coupled map lattice model of cascading failure theory to describe the cascading failure process of organizations in R&D projects, which is shown as below: 
(1)
Where s_i(t) means the state of organization i at time t, b_ij(t) means the state whether organization i is linked to j or not at time t, k_i(t) means the node degree of organization i at time t, tunable parameter ε∈(0,1) means the coupling degree between organizations. At time m, an external disturbance R is imposed on organization c and then causes this organization to fail. Then, all the other organizations' states will be calculated again according to the equation (1). In this way, the cascading failure process of nodes spreads in the organization networks.Thirdly, this paper proposes the influencing mechanism of how the actual duration of task i is affected by the failure of organizations that implement this task. More specifically, this paper proposes that the actual duration t_i' of task i is affected by three elements, which are the planned duration t_i of task i, the proportion of failed organizations against all organizations, the influencing degree of organization failure on the actual duration. Therefore, the actual duration of task i is calculated according to the following equation: 
                                       (2)
Where Ψ_i means the set of failed organizations that implement task i, ω means the influencing degree of organization failure on the actual duration.Finally, this paper explores how the organization failure influences the schedule risk of R&D project throughnumerical simulation under different elements, which are tunable parameter R and ε, average degree of network 〈k〉, attack strategy. The results show that the external disturbance R that is imposed on one organization node can eventually cause the duration delay of R&D project badly only when it reaches a certain threshold, i.e. critical disturbance threshold; This threshold has the negative correlation with the degree of coupling among the organizations, and has the positive correlation with the average degree of organization network; highest-degree attack can more easily lead to the occurrence of schedule risk than random attack and lowest-degree attack, and the gap between their consequences is becoming much larger with the coupling degree among the organizations being smaller.Takes the organization failure is taken as the element of schedule risk of R&D project, and analyzes how the organization failure influences the schedule risk of R&D project through numerical simulation is analyzed. The research work of this paper will provide a new view for R&D project schedule risk management under the context of networking.

Key words: R&D project, schedule risk, organization failure, organization-task network, coupled map lattice, numerical simulation