User Requirements Specification definition

User requirement specification (URS)—documented definition of the project. 

Qualification of equipment and validation of computer systems are not one-time events. They start with the definition of the product or project and setting user requirement specifications and cover the vendor selection process, installation, initial operation, ongoing use, and change control. 

The output of this activity will be the User Requirement Specifications (URS) or Project Definition that will be issued to the design consultant and evolved into a detailed design defining the assets required to meet the requirements. 

The first step in the evaluation process is to define and document the current system use and user requirement specifications. If the system will be changed in the foreseeable future, any resulting changes in the intended use of the system should be described as well. The definition should include a list of system functions, operational parameters and performance limits. For chromatography software required functions may include instrument control, data acquisition, peak integration through quantitation, file storage and retrieval and print-out of methods and data. If the system also includes spectrophotometric detectors, the functions for spectral evaluation should be specified as well. Table 2 lists items that should be included in the system documentation. 

A User Requirements Specification (URS) is a very important first step because it forms the basis of the System Definition and the selection of the supplier and influences the approach to validation. It should be the mechanism by which users have the opportunity to express their needs. Dividing the needs into musts and wants provides the project team with an indication of how to weigh the requirements during supplier selection. 

The most important factors for the entire process of equipment qualification and computer system validation in analytical laboratories are proper planning, execution of qualification according to the plan, and documentation of the results. The process should start with the definition of the analytical technique and the development of user requirement and functional specifications. For computer systems, a formal vendor assessment should be made. This can be done through checklists and vendor documentation with internal and/or external references. For very complex systems, it should go through a vendor audit. 

It is recognized that the URS may be superseded by the FDS as the definitive specification for system design. The URS, however, remains the technical and operations statement of user requirements and must be maintained under change control as an up-to-date document throughout the life of the system. The URS also remains the base document against which PQ is verified, and once the URS is approved a PQ test plan can be generated. 

In the Functional Specification (FS) the database architect converts the information gleaned from the user requirements into a definition of what the application wiU actually do (but not how it will do it). A good URS is prioritized because users tend to ask for the world, while management is only willing to fund a rocky islet. The FS must be based on, and directly traceable to, the URS. 

This concept ensures a strict definition of the application range of the standard to be applied. In addition, informative aimexes m be presented in order to give further examples and information to the user. The normative part of an analytical standard method in CEN and ISO includes at least the clauses listed below (ISO/IEC, 2001 ISO, 1998). Additional clauses, such as specific definitions or a list of minimum requirements needed, m be added to the standard, if relevant. 

The importance of requirements specification is now realized as it provides the written definition for the evaluation exercise. The key approach to evaluation is to develop an evaluation checklist for comparison of systems the users should grade each requirement as either mandatory or desirable . All those features falling into the essential category form the minimum requirements of the LIMS and the desirable category features are those that are useful to have but the users do not require them in order to perform their normal role. To aid objectivity, essential items can be given a numeric value this will give a total score for each system on offer. 

The three-part draft of the radioscopy standard pr EN 13068 is ready for the necessary european inquiries. This standard covers the requirements placed on the imaging system, the checking procedures as to the performance of the entire system and also the specifications of user guidelines for certain inspection tasks. The standard remains open to the definition of new inspection classes for future application cases. 

The next few steps are very similar to those required in any software project. One of the first stages is the clear definition of the knowledge domain. It must be clear which problems the expert system must solve. It is at this stage not the intention to define how this can be done. Clarity and specificity must be the major guides here. Fuzziness at this stage will, more than in classical software projects, have to be paid for later when different interpretations cause misunderstandings. Equally important is the clear definition of the end user(s). An expert system set up as decision support tool for professionals is totally different from an expert system that can be used as a training support for less professional people. 

Research users need full access to the functional elements of the spectrometer system and require the most efficient and flexible tools for MR sequence and application development. If the measurement methods delivered with the software do not adequately address the specific investigational requirements of a research team, modem NMR software is an open architecture for implementing new and more sophisticated functionality, with full direct access to all hardware controlling parameters. After evaluation, the new functionality can be developed with the help of toolbox functions that allow rapid prototyping and final builds, to enable the new sequence to be executed by non-experienced personnel and then used in routine applications. These toolboxes provide application oriented definitions and connect to standard mechanisms and routine interfaces, such as the geometry editor, configuration parameters or spectrometer adjustments. 

All the qualities that relate to runtime behavior should be captured as part of the behavioral specification of the system,3 including requirements about security, availability, and performance, because they contribute to the definition of acceptable behavior. For example, the need to authenticate users before permitting them to access certain operations should be... 

The preparation of a reference material requires substantial planning prior to undertaking a specific project (see Box 5.1). The process begins with the definition of the material to be produced, for example, preparation of a seawater-based reference material containing the nutrient elements N03, P04, and Si(OH)4 at concentration levels appropriate to oceanic samples and certified for these constituents." Such definitions arise either from internal decisions by reference material producers (such as NIST or NRC-Canada) typically in response to perceived needs, or through external pressure on these producers from potential users. (This report, for example, explicitly identifies a number of pressing needs for reference materials for the ocean sciences.)... 

Even though the definitions look similar, there is a distinct difference. While verification is of general nature, validation refers to specific intended use . In this sense a computer system that is developed for multiple users with multiple applications is verified rather that validated at the vendor s site. When the system is installed at the user s site for a specific task and the system is tested to meet the previously specified requirements, this process is defined as validation. If the system is intended to be used for different applications and more generic tests are done in the sense of EN ISO 8402 1995, this process again is called verification. 

Analysts and end users of the measurement results should be aware of the new dimension of the procedure validation definition given in ISO/IEC 17025, which requires that a procedure s performance parameters are fit for a specific intended use. In other words this means that the work of an analyst is not finished when performance capabilities of a specific method (or preferably procedure ) are evaluated, but he/she has to go a step further and check whether these characteristics are in compliance with the client s needs. Of course, it is up to the client to specify his/her re-quirements/properties the result should have. Furthermore, ISO/IEC 17025 is introducing evaluation of measurement uncertainty as a mean of performing validation through systematic assessment of all quantities influencing the result. 

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