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Problems with Definitions

The obvious advantage of this construction is that the complexity of authentication and disputes is independent of the number of risk bearers. The disadvantage is that a general suitable key-generation protocol is very inefficient however, see the last subsection for more efficient special cases. (Moreover, due to problems with definitions of multi-party function evaluation protocols, I did not even dare to call the security considerations below a proof sketch.)... [Pg.207]

The list of quality dimensions by both Gravin and Parasuraman et al. are widely cited and respected. However, one problem with definitions is that if time permitted the reader will find several other nsefnl definitions and dimensions. Wild s definition of design/process qnality does provide a broad framework to develop a company-specific quality strategy. [Pg.283]

Will humans ever be able to solve this problem If humans possessed the same limitations on computation as computers, then they would never be able to solve this (and many other) problems. However, math and science, as disciplines, assume that unknown problems with definite answers will eventually be knowable. Simply stated, the progress of science depends on the ability of humans to eventually solve such problems as these. [Pg.113]

Problems with definitions and differential rates of identification between schools and local authorities... [Pg.34]

The accident at the Three Mile Island nuclear plant clearly demonstrated that an alarm system can be counterprociuc tive. An excessive number of alarms can distract the operator s attention from the real problem that needs to be addressed. Alarms that merely tell the operator something that is already known do the same. In fac t, a very good definition of a nuisance alarm is one that informs the operator of a situation of which the operator is already aware. The only problem with applying this definition is determining what the operator already knows. [Pg.770]

It may be seen from Fig. 2.80 that some plastics experience the change from ductile to brittle behaviour over a relatively narrow temperature range. This permits a tough/brittle transition temperature to be quoted. In other plastics this transition is much more gradual so that it is not possible to attribute it to a single value of temperature. In these circumstances it is common to quote a Brittleness Temperature, rg(l/4). This temperature is defined as the value at which the impact strength of the material with a sharp notch (1/4 mm tip radius) equals 10 kJ/m. This temperature, when quoted, gives an indication of the temperature above which there should be no problems with impact failures. It does not mean that the material should never be used below Tb(1/4) because by definition it refers only to the sharp notch case. When the material has a blunt notch or is un-notched its behaviour may still be satisfactory well below Tb(1/4). [Pg.151]

Local ventilation is often a very important part of the ventilation system, both in function and in construction, which makes a specific definition difficult. In addition to the above definitions it can be defined as ventilation of a separate volume inside a large room, as opposed to general ventilation, which is for the complete room or building. One problem with this definition is that local ventilation systems could function as localized ventilation in one surrounding and as general ventilation in another surrounding e.g., a ceiling inlet combined with floor exhaust is a local ventilation system in a... [Pg.809]

Note, however, that the frequency/malfunction relationship is not mutually exclusive and a specific mechanical problem cannot definitely be attributed to a unique frequency. While frequency is a very important piece of information with regard to isolating machinery malfunctions, it is only one part of the total picture. It is necessary to evaluate all data before arriving at a conclusion. [Pg.674]

The solution of system (6.56) is a very complicated mathematical problem it definitely needs numerical calculations on some stages of processing. At least two successful attempts to overcome these difficulties are well known in the literature. The first method was put forward by Sack and expresses the solution through a continuous fraction. The second was proposed by Fixman and Rider [29], and deals with a kinetic... [Pg.212]

The problem with the Arrhenius definitions is that they are specific to one particular solvent, water. When chemists studied nonaqueous solvents, such as liquid ammonia, they found that a number of substances showed the same pattern of acid-base behavior, but plainly the Arrhenius definitions could not be used. A major advance in our understanding of what it means to be an acid or a base came in 1923, when two chemists working independently, Thomas Lowry in England and Johannes Bronsted in Denmark, came up with the same idea. Their insight was to realize that the key process responsible for the properties of acids and bases was the transfer of a proton (a hydrogen ion) from one substance to another. The Bronsted-Lowry definition of acids and bases is as follows ... [Pg.97]

Chlorambucil - there is no problem with the quantitation ion (at m/z 254), although the second ion proves to be a little difficult. While the ion at m/z 303 is the obvious choice, this is not very intense and therefore for samples containing small amounts of analyte the precision of measurement of this ion will be reduced and it may not be detectable at all levels at which the quantitation ion is observed. We could possibly consider the (M- -2) ion, as the combination o/m/z 254 (high mass, and therefore reasonable specificity), the presence of one chlorine, and the chromatographic retention time could be considered sufficient for definitive identification in those cases in which the intensity o/m/z 303 is insufficient. [Pg.73]

In a similar way, electrochemistry may provide an atomic level control over the deposit, using electric potential (rather than temperature) to restrict deposition of elements. A surface electrochemical reaction limited in this manner is merely underpotential deposition (UPD see Sect. 4.3 for a detailed discussion). In ECALE, thin films of chemical compounds are formed, an atomic layer at a time, by using UPD, in a cycle thus, the formation of a binary compound involves the oxidative UPD of one element and the reductive UPD of another. The potential for the former should be negative of that used for the latter in order for the deposit to remain stable while the other component elements are being deposited. Practically, this sequential deposition is implemented by using a dual bath system or a flow cell, so as to alternately expose an electrode surface to different electrolytes. When conditions are well defined, the electrolytic layers are prone to grow two dimensionally rather than three dimensionally. ECALE requires the definition of precise experimental conditions, such as potentials, reactants, concentration, pH, charge-time, which are strictly dependent on the particular compound one wants to form, and the substrate as well. The problems with this technique are that the electrode is required to be rinsed after each UPD deposition, which may result in loss of potential control, deposit reproducibility problems, and waste of time and solution. Automated deposition systems have been developed as an attempt to overcome these problems. [Pg.162]

Define the analytical approach, such as the material and the analytes to be looked for so as to (possibly) answer the questions asked and to solve the problems. Select an appropriate analytical method, with definition of its purpose and utility. If none of the available methods fits the analytical purpose, try to deduce method approach(es) from existing methods for structurally related compounds or materials by introducing carefully selected modifications and adaptations. [Pg.51]

The traditional definition of menorrhagia is a menstrual blood loss of greater than 80 mL per cycle. This definition has been questioned for several reasons, including difficulty with quantifying menstrual blood loss in clinical practice. Many women with heavy menses but blood loss of less than 80 mL will merit consideration for treatment because of problems with containment of flow, unpredictable heavy flow days, and other associated symptoms.8,9... [Pg.752]

The problem with the payout period is that it does not consider the timing of the payments or the profits earned by the plant after the payout period is over. To illustrate the importance of the former, suppose a plant has the same prestartup expenses as the one in Example 10-3. Assume it has a profit of 5,000,000 per year for the first 5 years and from then on earns 7,000,000 per year. The payout time for this plant is 5 years, the same as for the plant in Example 10-3. The return on investment of the two mature plants is the same. Yet this proposed plant has a definite advantage over the one in Example 10-3. This is illustrated in the following example. [Pg.289]

This chapter treats the descriptions of the molecular events that lead to the kinetic phenomena that one observes in the laboratory. These events are referred to as the mechanism of the reaction. The chapter begins with definitions of the various terms that are basic to the concept of reaction mechanisms, indicates how elementary events may be combined to yield a description that is consistent with observed macroscopic phenomena, and discusses some of the techniques that may be used to elucidate the mechanism of a reaction. Finally, two basic molecular theories of chemical kinetics are discussed—the kinetic theory of gases and the transition state theory. The determination of a reaction mechanism is a much more complex problem than that of obtaining an accurate rate expression, and the well-educated chemical engineer should have a knowledge of and an appreciation for some of the techniques used in such studies. [Pg.76]

To diagnose the surface blemish problem several analytical techniques were employed. First, the samples were photo-documented. Since an aesthetic problem is by definition a problem with the visual appearance of an item, it is important to ascertain if all the defects are different or of the same nature. With close inspection, the sun visor arms were found to contain two distinct types of defects. Figure 1(a) shows what was called the Type A defect and Figure 1(b) shows the so-called Type B defect. These images were acquired using a stereomicroscope coupled with a digital camera. [Pg.609]

Discussions about the PA usually focus on definitions. Such definitions are plentiful, they depend on the scientific and social background of their authors, and they all contain elements of truth and error. One of the basic problems with the PA is that there is no such thing as an overall definition. The application of the PA is always heavily context-dependent. It is no use solving problems associated with applying the PA by means of a generally accepted definition, since it is difficult to define a principle sharply where uncertainty is the main element. The definition of terms and concepts like uncertainty always depend on the scientific, social, cultural and economic background of individuals employing them. [Pg.292]

Unfortunately, even the planning of green biotechnology has now evolved into a wicked problem with complex structures and no obvious causal chains. This applies also to the PA. These problems cannot be determined completely in a quantitative and scientific manner, and there are no existing solutions in the sense of definitive and objective answers alone. Wicked problems have been addressed mainly through formalized (linear) methods that are suitable only for the solution of tame problems. [Pg.294]


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