Define, measure, analyze control

DMADV Define — measure — analyze - improve - control... 

The Six Sigma approach is composed by five steps, i.e. the DMAIC algorithm (Fig. 1) Define, Measure, Analyze, Improve and Control. 

Many readers will know that Six Sigma practitioners utilize a similar process. Its acronym is DMAIC, which stands for Define-Measure-Analyze-Improve-Control. This cycle is similar to PDCA either approach is valid. 

DMIAC Define, Measure, Analyze, Improve, and Control. A process for implementing supply chain changes associated with the Six Sigma improvement process. (A foundation for operational excellence, Supply Chain Management Review, March/April 2003)... 

Six sigma Six sigma is one of the more recent popular approaches to QA that is based on a tight statistical approach to the production of a product. The name arises from a desire to limit the tolerance of a product to plus or minus six standard deviations and thus have only 3.4 defects per million. (This is the fraction outside - - 4.5 standard deviations from the mean the method allows for some measurement uncertainty.) In order for the statistics to hold, the system must be in statistical control and the defects must be random and normally distributed. There is a heavy reliance on control charts and the system is built around what to do if there is evidence for nonconformity. For a nonconforming product six sigma institutes an approach with the acronym DMAIC — define, measure, analyze, improve, control. This has been implemented in some organizations, such as pharmaceutical companies, which produce large volumes of chemicals. However, strict statistical control of chemical products is not always easy, and considerations of the measurement process also needs to be taken into account. 

DMAIC define, measure, analyze, improve, control... 

Some of the Six Sigma models are DMAIC (Define, Measure, Analyze, Improve, Control), which is used to improve the existing process, and DMADV (Define, Measure, Analyze, Design, Verify), which is used to employ the new products. 

DMAIC Define, Measure, Analyze, Improve, and Control... 

A quality management system s process should follow a standard Six Sigma process improvement life cycle that includes the following steps define (process and metrics), measure and control (identify problems and issues), analyze (analyze problems and issues), and improve (implement) circling back to measure and control [11]. An example of a process improvement life cycle can be seen in Figure 9. 

The final product quality must satisfy the demands of the initial objectives. That means that along all the different operations/processes, the transformations will be controlled not only to define, measure, optimize the operating conditions but to be able to analyze the constituents, to describe the history of evolution of physical and chemical structures. As usual, adapted analyses are a very important complementary part of processing. 

In a so-called preperiod, one or several control sample(s) of every analysis series are analyzed together with the samples. For each control sample, a precision check and, if possible, an accuracy check are carried out by comparison with given values. If the analysis quality is acceptable, warning and intervention limits are defined and the quality control card is drawn. In the subsequent control period, compliance with the defined limits is monitored by measuring further control samples. The results from these control analyses or the statistical quantities derived from them are continuously registered in the quality control card. The abscissa relates to the continumg serial number, whereas control values are registered on the ordinate. 

The flow sensor is at the core of volume flow controllers used in air-conditioning. These controllers are important components in modern HVAC applications. They measure, analyze, and control room-air flow in order to supply air in defined quantities to entire buildings or individual rooms. Other target markets for this flow sensor include test facilities, gas handling, and medical technology. 

Fig. 3—Measurement of surface by HDI surface reflectance analyzer. In electromagnetic radiation (light), the polarization direction is defined as the direction of the electric field vector. The incident polarization of the light can be controlled. The instrument uses a variety of detectors to analyze the reflected polarization state of the light. (U.S. Patent 6,134,011). (a) Plane of the disk The SRA uses a fixed 60 degree (from the surface normal) angle of incidence. The plane of incidence is the same as the paper plane (b) Pit on a surface detected by reflected light channels of HDI instrument (c) Scratches on disk surface measured by HDI surface reflectance analyzer (d) Particles on the surface of disk detected by reflected light (black spot) and by scattered light (white spot) [8].

Limits of detection for each of the three parent herbicides in surface and groundwater were determined using results obtained from control samples analyzed along with hundreds of surface and ground water sets during the years 1995-2001. In each of these years, the calculated LODs (minimum detectable true concentrations/detection) were below 0.03 pg for acetochlor and metolachlor and 0.05 pg for alachlor. A detection criterion is a measured concentration threshold that defines a likely upper bound for samples not containing the analyte. If the actual concentration of an analyte is at this detection limit or greater, there is at least a 95% chance of detection. 

In order to use the stopped-flow technique, the reaction under study must have a convenient absorbance or fluorescence that can be measured spectrophotometri-cally. Another method, called rapid quench or quench-flow, operates for enzymatic systems having no component (reactant or product) that can be spectrally monitored in real time. The quench-flow is a very finely tuned, computer-controlled machine that is designed to mix enzyme and reactants very rapidly to start the enzymatic reaction, and then quench it after a defined time. The time course of the reaction can then be analyzed by electrophoretic methods. The reaction time currently ranges from about 5 ms to several seconds. 

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