In the United States， for example， the U. S. Army Corps of Engineers has in-house capabilities to deal with planning， budgeting， design， construction and operation of waterway and flood control structures. Other public agencies， such as state transportation departments， are also deeply involved in all phases of a construction project. In the private sector， many large firms such as DuPont， Exxon， and IBM are adequately staffed to carry out most activities for plant expansion. All these owners， both public and private， use outside agents to a greater or lesser degree when it becomes more advantageous to do so.
      The project life cycle may be viewed as a process through which a project is implemented from cradle to grave. This process is often very complex；however， it can be decomposed into several stages as indicated by the general outline in Figure 1.1. The solutions at various stages are then integrated to obtain the final outcome. Although each stage requires different expertise， it usually includes both technical and managerial activities in the knowledge domain of the specialist. The owner may choose to decompose the entire process into more or less stages based on the size and nature of the project， and thus obtain the most efficient result in implementation. Very often， the owner retains direct control of work in the planning and programming stages， but increasingly outside planners and financial experts are used as consultants because of the complexities of projects. Since operation and maintenance of a facility will go on long after the completion and acceptance of a project， it is usually treated as a separate problem except in the consideration of the life cycle cost of a facility. All stages from conceptual planning and feasibility studies to the acceptance of a facility for occupancy may be broadly lumped together and referred to as the Design/Construct process， while the procurement and construction alone are traditionally regarded as the province of the construction industry.