Identifiability problem

History The histoiy of a plant forms the basis for fault detection. Fault detection is a monitoring activity to identify deteriorating operations, such as deteriorating instrument readings, catalyst usage, and energy performance. The plant data form a database of historical performance that can be used to identify problems as they form. Monitoring of the measurements and estimated model parameters are typic fault-detection activities. 

Preliminary Test Operation of the unit shoiild be set at the test protocol conditions. A preliminaiy set of samples should be taken to identify problems with instruments, measurements, and sample locations. This preliminaiy set of measurements should also be an yzed in the same manner that the full-test results will be analyzed to ensure that the measurements wiU lead to the desired results. Modifications to the test protocol can be made prior to exerting the effort and resources necessary for the complete test. 

Manways left off trays. Poor separation. Everything looked good. Scan interpretation did not identify problem until after the tower was opened. In fact, the trays with properly installed manways were thought to be entraining. Installation error. 

We must not forget the client. The client review is an excellent tool that can be used to get the client s first impression of safety performance. This has been shown to be especially effective when conducted on a formal basis after a phase of the project, or the entire project, has been completed. The PM and the SM should arrange to meet the client represen-tative(s) in a face-to-face meeting to discuss safety performance and possibly other parameters of the recently completed job, or phase of job. The information obtained from the review is immediately analyzed. Once analyzed, it can be used to prevent recurrences of identified problems, to publicize good practices and innovative approaches to problem solving, and to perform work more safely and efficiently. 

Any time PPE is used, its proper use should be assessed. An effeetive inspeetion proeess ean help identify problem areas with PPE. Observations ean be made to visually inspeet PPE as the walk-through is being eondueted. Eirst, you should determine if the PPE observed what has been speeified in the HASP. Seeond, determine if you have observed instanees when the PPE was overproteetive, underproteetive, or inadequate in any way. 

In collecting the data care should be taken to avoid data paralysis (see Part 2 Chapter 14). The various quality tools can be used to prioritize the identified problems and corresponding decisions. As with all data collection tasks, you should show a direct correlation between what you are collecting and the goals to be achieved and all conclusions should lead to positive action, otherwise the effort has been futile. 

In subsequent sections the application of PIFs to various aspects of error reduction will be described. One of the most important of these applications is the use of comprehensive lists of PIFs as a means of auditing an existing plant to identify problem areas that will give rise to increased error potential. This is one aspect of the proactive approach to error reduction that forms a major theme of this book. This application of PIFs can be used by process workers as part of a participative error reduction program. This is an important feature of the human factors assessment methodology (HFAM) approach discussed in Section 2.7. 

This phase involves the performance of check-out and nm-in activities to ensure that equipment and piping are mechanically integrated, functionally located and free of obstructions It is also necessary to ensure that instruments and controls are fimchoning properly and that all previously identified problems have been addressed. All maintenance and operating procedures need to be verified as correct. 

Measurement must address end-of-pipe performance (through measures such as injury rates and gallons spilled), process efficiency and indicators of performance (through measures such as in service failure of equipment). Using indicators should make it possible to identify problems before they result in poor performance. Process efficiency measurement helps track implementation of the project and continuous improvement in the use of resources. 

The needle stick log will help both employees and employers track all needle sticks to help identify problem areas. The log must be maintained to protect the confidentiality of the injured employee. In addition, employers must have a written Exposure Control Plan that is updated annually. During the annual review, inquiries must be made about new or prospective safer options. If new safer devices are available, they should be adopted for use in the agency. The new guidelines will help reduce needle stick injuries among health care workers and others who handle medical sharps. Safety engineered devices such as self-sheathing needles and needleless systems can be used. 

Analytical and problem-solving skills initially help in analysing situations correctly and identifying problems. They also enable one to view issues from different perspectives and to devise a range of solution alternatives. Examining a problem from different angles also helps the mentor to ... 

The regulatory process should be routinely and systematically monitored in order to identify problems in the process and determine whether the activities actually carried out are consistent with the intended course of action. Several approaches may be employed for assessing the performance of dmg regulatory authorities self-review, supervisory body review and peer review. These approaches can complement one another in appraising the performance of the DRA, as well as assisting it to identify areas for improvement. 

Regulatory processes should be systematically monitored in order to identify problems and determine whether the actual activities match the intended actions. 

Prior to a method trial, the FDA strongly recommends that a second analyst or independent laboratory perform the method. The independent analyst is asked follow the method SOP as written. This analyst should not have been involved in developing the method or be familiar with it in any way. The purpose of the independent analysis is to determine if a qualified chemist can perform the method described without input other than that provided in the written instmctions. This trial mn will typically identify problems with the SOP that are not apparent to the method developer. Although not required by the FDA, the independent assessment can identify potential problems with the method SOP prior to the lengthy and costly method trial. A trial mn offers the method developer an opportunity to correct problems and to increase the probability that subsequent method trials will be successful. Finally, the method developer should realize that the variability achieved in his/her laboratory is often less than that realized by less experienced analysts. If a method cannot achieve a suitable degree of repeatability in the developer s laboratory, it should not be expected to do any better in other laboratories. 

This same [e] experimental protocol leads to a graphical overlay plot that yields valuable kinetic information if the two experiments described in Table 50.1 are plotted together as reaction rate vs. [2], the two curves will fall on top of one another ( overlay ) over the range of [2] common to both only if the rate is not significantly influenced by changes in the overall catalyst concentration within the cycle, including catalyst activation, deactivation or product inhibition. Overlay in same excess plots, therefore, may be used to confirm catalyst robustness or identify problems such as catalyst deactivation or product inhibition. 

A small percentage of the buildings in the United States with indoor radon concentrations in excess of 4 pCi/L can be attributed to building materials. Most of the building material problems have arisen from the use of known radium- or uranium-rich wastes such as aggregate in block or as backfill around houses. None of the houses studied in the U.S. EPA Radon Reduction Demonstration program have had any identifiable problem associated with radon from building materials. 

Assignment of a specific model structure to a real data set should, among other things, take into account the identifiability problem. Simply stated, the identifiability problem occurs when more than one model structure and associated parameter sets are able to describe the actual data, typically drug plasma concentration-time data. In other words, how unique is the parameter set, and what... 

A long-term but substained effort on sampler intercomparison would be advantageous in identifying problems. 

An excellent safety program strives to identify problems before they occur. Chemical engineers must understand all aspects of toxic release to prevent the existence of release situations and to reduce the impact of a release if one occurs. This requires a toxic release model. 

Although the method is easy to use, it clearly identifies problems that may need additional work, such as a QRA. It also identifies problems, which may be deemphasized because the consequences are insignificant. 

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