Computer system identification

The handbook additionally provides an extensive overview and comparison of commercially available computer systems and software for chemical emergency planning. This section provides technical guidance for hazard analysis and identification implementing regulatory requirements and descriptions of computer applications and systems applicable under SARA Title III. 

Technical benefits are also obtained more readily from a computer system in that if sound identification of assets is established through their asset number, codes etc., similar assets can be examined in the event of a failure of any similar asset, and spares can be held in stock to cover the range of assets for which they are required, rather than for each individual asset. In preparing the asset register and respective work tasks, these can also be more easily duplicated with respect to similar assets than is possible with a manual system. 

The PBL reactor considered in the present study is a typical batch process and the open-loop test is inadequate to identify the process. We employed a closed-loop subspace identification method. This method identifies the linear state-space model using high order ARX model. To apply the linear system identification method to the PBL reactor, we first divide a single batch into several sections according to the injection time of initiators, changes of the reactant temperature and changes of the setpoint profile, etc. Each section is assumed to be linear. The initial state values for each section should be computed in advance. The linear state models obtained for each section were evaluated through numerical simulations. 

With the commercially available MS—MS instruments in the 1990s, MS-MS helped to overcome these identification obstacles via CID in MS—MS mode or via ion trap in MS mode. In parallel, the applicability of MS—MS and MS by CID on tandem or ion trap MS become much easier and more informative with new MS spectrometric hardware, which is supported by the implemented improved computer systems. This combination of high-end data systems with more automated MS-MS and MS instruments facilitates the application of MS-MS and leads to a tremendous increase in the information output. 

There are several computer software packages that are quite helpful in applying some of the computationally intensive methods. The PC-MATLAB System Identification Toolbox (The Math Works, Inc., Sherborn, Mass.) is an easy-to-use, powerful software package that provides an array of alternative tools,... 

Many applications dI the quadrupole mass spectrometer use u gas or liquid chromalograph to inlroduce the sample into Ihc ionizer. When the speelromeict is used in this manner, it is nuisl common In scan a w ide inttss range (50-1 OCX) amul al rates on the order of 1000 amu/sceoiid for compound identification For process analyses, it is mosi ennunon lo introduce the sample directly inio the ionizer and scan a shorter mass range. For both applications, computer systems are needed to collect die enormous amounts of data produced. 

Although not yet available, it is likely that Web-based performance testing systems will become available in the near future. Web-based systems will permit selected tasks to be presented on computers equipped with appropriate Web browser software. Hardware requirements include Internet access and appropriate memory and software to support Web-based applications. Depending on the design of the Web-based system, it is could be possible to tailor the specific tasks presented for the performance testing system from a menu of options. Alternatively, testing systems consisting of a standardized array of tasks can also be chosen. As such, the start-up costs of Web-based systems should be lower than with personal or handheld computer systems. Subject identification, date, and time can be recorded at the start of a test, and data from multiple subjects and test occasions can be stored in a central file for easy access to the data. 

The established methodology for computer system validation enables identification and control of each life-cycle phase and its associated document deliverables. It is also recognized that throughout the validation life cycle there is a level of dependency on the methods, services, and resources of the computer system supplier. 

In many instances operating system software has already been developed and is offered as a fundamental part of the computer system ready for application software to be developed or configured. In such cases it is prudent to establish the existence of the respective software quality assurance plans and procedures and the design, development, and testing records. Identification and examination of this documentation can be conducted and recorded as part of the supplier audit. (See Sec. VI.)... 

In order to remedy problems quickly or to avoid system errors, appropriate procedural controls must be applied to (a) enable early identification of an imminent breakdown, and (b) initiate appropriate preventive action. The next section suggests a course of action to follow to identify, analyze, and record computer system incidents, and to implement and test the corrective action taken. 

The purpose of the following checklist is to help to determine if a computer system complies with the FDA Rule 21 CFR 21 Part 11 for electronic records and electronic signatures. This audit questionnaire apphes to systems that meet the definition of a closed system as defined in Section 11.3 (b)(4) of the rule and which do not utilize biometrics identification methods. 

SLC processes and the identification of problems relating to the validation of computer systems. 

All operations performed on a sample must be recorded in a notebook or computer system. Chromatograms, spectra and other instrumental outputs must be labelled with the sample identification. 

Combined GC-MS-computer systems with repetitive scanning can lead to the identification of GAs as minor components of complex extracts at levels down to 1CT- -1 g. In such cases mass fragmentograms can be constructed in which the distribution of ions of particular m/e values are plotted throughout a GC-MS run. Thus if the presence of a particular GA is suspected, characteristic ions in the mass spectrum of the derivatized GA are plotted. An identification can be made if the ions peak at the same retention time as the GA and have the same relative intensity as in the mass spectrum of the authentic compound (see Figure 6). In this way GAs can be detected which are masked in the GC trace by other compounds of similar retention time (cf. 33). 

Figure 1 shows a computational framework, representing many years of Braun s research and development efforts in pyrolysis technology. Input to the system is a data base including pilot, commercial and literature sources. The data form the basis of a pyrolysis reactor model consistent with both theoretical and practical considerations. Modern computational techniques are used in the identification of model parameters. The model is then incorporated into a computer system capable of handling a wide range of industrial problems. Some of the applications are reactor design, economic and flexibility studies and process optimization and control. 

Mass spectrometry (MS) is now a well-accepted tool for the identification as well as quantitation of unknown compounds. The combination of MS with powerful separation methods such as gas chromatography (GC) or high-performance liquid chromatography (LC) provides a technique which is widely accepted for the identification of unknown components in complex mixtures from a wide variety of problems such as environmental pollutants, biological fluids, insect pheromones, chemotaxonomy, and synthetic fuels. The importance of such analyses has grown exponentially in the last few years there are now well over a thousand GC/MS instruments in use around the world, most with dedicated computer systems which make possible the collection from each of hundreds of unknown mass spectra per day (1). 

The performance of computer systems should be monitored to establish evidence that they dehver service levels required. The intent is also to anticipate any performance problems and initiate corrective action as appropriate. Performance monitoring can be seen as an extension to process performance qualification. A key step is the identification of appropriate performance parameters to monitor. 

It is important to appreciate that some data may be transient and will never be stored to durable media, while other transient data may be processed to derive data before being stored. Both transient and stored data must be protected from unauthorized, inadvertent, or malicious modification. It is expected that a register of authorized users, identification codes, and scope of authority of individuals to input or change data is maintained. Some computer systems lock-down data, denying all write-access. Secnrity arrangement is discussed in detail elsewhere in this chapter. 

Align security measures for the computer system with your corporation s Information Asset Protection Policies (lAPP) and coordinate with the building and/or plant security plans. For some systems, strict compliance with specific security requirements mentioned in the lAPP may not be possible given proprietary system limitations. Examples may include unique user identification codes, specified lengths for user identification codes and passwords, or inactivity time-outs. Use a deviation change process to document and justify these situations. 

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