how to reduce the project duration by four weeks

Yes the amount of time specified for the first 5 seems sufficient and hopefully they can be reduced however be careful not to spend enough time in the analysis and design because if you try to save time in the beginning then the time you save will be used up in the development and testing later. Management will probably pressure you to spend less time in the beginning but that is ussuallly a mistake. It is difficult to get management to understand that quality software development takes time. Management will want it done as fast as possible and they will be impressed by the people that do it the fastest even if they work a lot of overtime to do it; that is assuming that the developer is salaried and is not paid extra for overtime. The problem is that people that work a lot of overtime to debug their software usually produce buggy software that can cost more overall. It is difficult to get management to understand that.