Professional and Scientific Staff Management (PSSM) is a unique type of temporary staffing agency. Many organizations today hire highly skilled technical employees on a short-term, temporary basis to assist with special projects or to provide a needed technical skill. PSSM negotiates contracts with its client companies in which it agrees to provide temporary staff in specific job categories for a specified cost. For example, PSSM has a contract with an oil and gas exploration company, in which it agrees to sup- ply geologists with at least a masters degree for $5000 per week. PSSM has contracts with a wide range of companies and can place almost any type of professional or scientific staff members, from computer programmers to geologists to astrophysicists. When a PSSM client company determines that it will need a temporary professional or scientific employee, it issues a staffing request against the contract it had previously negotiated with PSSM. When a staffing request is received by PSSMs contract manager, the contract number referenced on the staff- ing request is entered into the contract database. Using information from the database, the contract manager reviews the terms and conditions of the contract and determines whether the staffing request is valid. The staffing request is valid if the contract has not expired, the type of professional or scientific employee requested is listed on the original contract, and the requested fee falls within the negotiated fee range. If the staff- ing request is not valid, the contract manager sends the staffing request back to the client with a letter stating why the staffing request cannot be filed, and a copy of the letter is filed. If the staffing request is valid, the contract manager enters the staff- ing request into the staffing request database, as an outstanding staffing request. The staffing request is then sent to the PSSM placement department. In the placement department, the type of staff member, experience, and qualifications requested on the staffing re- quest are checked against the database of available professional and scientific staff. If a qualified individual is found, he or she is marked reserved in the staff database. If a qualified individual cannot be found in the database or is not immediately available, the placement department creates a memo that explains the inability to meet the staffing request and attaches it to the staffing request. All staffing requests are then sent to the arrangements department. In the arrangement department, the prospective temporary employee is contacted and asked to agree to the placement. After the placement details have been worked out and agreed to, the staff member is marked placed in the staff database. A copy of the staffing request and a bill for the placement fee is sent to the client. Finally, the staffing request, the unable to fill memo (if any), and a copy of the placement fee bill is sent to the contract manager. If the staff- ing request was filled, the contract manager closes the open staffing request in the staffing request database. If the staffing request could not be filled, the client is notified. The staffing request, placement fee bill, and unable to fill memo are then filed in the contract office. c. Create the DFD fragments for each of the four use cases outlined in part a, and then combine them into the level 0 DFD. d. Create a level 1 DFD for the most complicated use case.