Mode confusion

The consequences of breakdown in mode awareness were fairly small in these system designs. Operators seemed able to detect and recover from erroneous actions relatively quickly before serious problems resulted. Sarter and Woods conclude that, in most cases, mode confusion in these simpler systems are associated with errors of commission, that is, with errors that require a controller action in order for the problem to occur [181]. Because the human controller has taken an explidt action. 

Understanding more about particular types of mode confusion errors can assist with design. T vo common types leading to problems are interface interpretation modes and indirect mode changes. 

Again, errors related to mode confusion are related to problems that human supervisors of automated controllers have in maintaining accurate process models. Changes in human controller behavior in highly automated systems, such as the changes in pilot scanning behavior described earlier, are also related to these types of mode confusion error. 

Rodriguez, M., M. Katahira, M. de Villepin, and N. G. Leveson. Identifying mode confusion potential in software design. Digital Aviation Systems Conference, Philadelphia, October 2000. 

Mode confusion is when the system or product operator is unaware that the current mode of operation is not the desired or intended mode. It involves incorrect or erroneous awareness of the operational mode. The confusion could be due to many different factors, such as human error, the system inadvertently jumping into the wrong mode, and display errors or failures. System safety is concerned about mode confusion because the operator may execute potentially hazardous commands if the system is in the incorrect mode. In critical applications, the operator can be forced into mode confusion due to poor system design or poor UI design. 

The editor provides two modes for drawing the structure and the draw mode. This distinction is important for differentiating chemical information from conventional drawings. Both modes are switchable and provide an extensive set of features in the menu bar to create chemical structures and reactions, or just drawings. The number of options can be quite confusing for beginners however, one becomes accustomed to them after a short period of vocational adjustment. 

Another form of array is called a microchannel plate detector. A time-of-flight (TOP) mass spectrometer collects ions sequentially in time and can use a point detector, but increasingly, the TOP instrument uses a microchannel plate, most particularly in an orthogonal TOP mode. Because the arrays and microchannel plates are both essentially arrays or assemblies of small electron multipliers, there may be confusion over their roles. This chapter illustrates the differences between the two arrays. 

The elastic and viscoelastic properties of materials are less familiar in chemistry than many other physical properties hence it is necessary to spend a fair amount of time describing the experiments and the observed response of the polymer. There are a large number of possible modes of deformation that might be considered We shall consider only elongation and shear. For each of these we consider the stress associated with a unit strain and the strain associated with a unit stress the former is called the modulus, the latter the compliance. Experiments can be time independent (equilibrium), time dependent (transient), or periodic (dynamic). Just to define and describe these basic combinations takes us into a fair amount of detail and affords some possibilities for confusion. Pay close attention to the definitions of terms and symbols. 

Spatial Profiles. The cross sections of laser beams have certain weU-defined spatial profiles called transverse modes. The word mode in this sense should not be confused with the same word as used to discuss the spectral Hnewidth of lasers. Transverse modes represent configurations of the electromagnetic field determined by the boundary conditions in the laser cavity. A fiiU description of the transverse modes requires the use of orthogonal polynomials. 

The rehabihty level of a product also depends on the operating or environmental conditions, which may produce a variety of failure modes. Rehabihty can only be assessed relative to a defined environment. Unless these points are estabhshed clearly, confusion surrounds any quoted rehabihty number for a product. 

To receive a filing date, an appHcation made on the basis of intent-to-use must include "a claim of bona fide intention to use the mark in commerce," a description of the goods upon or in connection with which the appHcant has the intention to use the mark and the mode and manner in which it is to be used, and a statement that the appHcant is entitled to use the mark and that, to the best of the appHcant s knowledge, no other person or entity has the right to use the mark or a confusingly similar mark. A drawing of the mark must be submitted with the appHcation. 

A classic feature of erosion-corrosion is the directional character of the metal loss. The metal loss will be oriented along the direction of fluid flow or according to turbulence patterns. However, other corrosion modes may produce directionality in metal loss and could be confused... 

When generators are specified, it should be realized that both mechanical and electrical requirements differ between units which will be used for standby service and units which will be operated continuously. Typically, standby units have less copper in their windings than continuous duty units, causing standby units to reach higher temperatures if operated continuously, and thus reducing life. Standby units, as classified by most manufacturers, are not to be confused with units which are alternated weekly (or on some other regular basis), but which are operated continuously when they are on line. This operating mode should be considered continuous duty. ... 

The FMECA table should be concise, complete, and well organized. This table should identify equipment and relate it to a system drawing or location. This is to prevent confusion when similar equipment is used in different locations. One of tlie limitations of FMECA is tliat the table must include ALL failure modes for each piece of equipment and effects of each failure along witli tlie associated criticality ranking. Table 17.5.3 shows a sample chart tliat can be completed for tlie FMECA table. 

Common confusions Vibration analysts often confuse resonance with other failure modes. Since many of the common failure modes tend to create abnormally high vibration levels that appear to be related to a speed change, analysts tend to miss the root cause of these problems. 

Fig. 43. Binding mode of the coligands in 95 and 96. The bowlshaped representation of the ligand (L19)2 should not be confused with the one used for the cyclodextrins.

Polycarbonate is a thermoplastic and is often marketed under trade-names such as Lexan or Tuffak. It should not be confused with acrylic plastics, marketed under tradenames such as Plexiglas or Lucite, which are flammable and exhibit a brittle failure mode. 

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