Descriptive Approaches

Different approaches and techniques have been deployed to support decision-making processes. A general taxonomy distinguishes between transactional and analytical systems. Transactional systems are concerned with the acquisition, processing, and communication of data over the enterprise. Otherwise, analytical tools introduce some intelligence to evaluate and/or rank the alternatives available. This section provides a brief description of those analytical tools commonly used to solve problems arising in the SCM. 

The normative category involve these approaches whose main goal is the optimization or improvement mathematical programming models and heuristic techniques. 

According to the Mathematical Programming Society, a problem of mathematical programming or optimization seeks to minimize or maximize a real function of real or integer variables, subject to constraints on the variables. Optimization problems are made up of three basic components (i) an objective function to be minimized or maximized (e.g., in the area of PSE it is usual to maximize the profit or minimize the total cost) (ii) a set of variables which affect the value of the objective function (e.g., the amounts of different resources used or the time spent on each activity) and (iii) a set of constraints that allow the variables to take on certain values but exclude others. The term mathematical programming refers to the study of these problems, their 

The approaches to deal with uncertainty can be classified into reactive and preventive procedures. Reactive approaches attempt to modify a nominal plan obtained by a deterministic formulation so as to adjust it to changes. Rule-based methodologies, heuristics, and intelligent agents are commonly used to perform the required modifications. However, they are problem-specific and consequently difficult to extend. 

Model Predictive Control (MPC) has been also appUed to SC problems as a reactive approach. MPC is a control sfiategy based on the explicit use of a process model to predict the process performance over a period of time (Camacho and Bordons 1995). The model attempts to predict the control variables for a set of time periods. Predicted confiol variables depend on disturbance forecasts (i.e., demand, prices, and interest rates) and also on a set of given parameters that are known as control inputs. The MPC algorithm attempts to optimize a performance criterion that is a function of the control variables. Only a portion of the control variables, the portion corresponding to the following time period, is applied to the system. Next, as new control input information and disturbance forecasts are collected, the whole procedure is repeated, which produces a feed-forward effect and enables the system to counteract the environment dynamics. The procedure is illustrated in Fig. 1.6. 

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Phosphorus by Heal covered developments up to the end of the 1970s. This opus contributed authoritative insights into the fascinating chemistry of S-N compounds. It used a descriptive approach that drew attention to the many facets of the synthesis, structures and reactions that were poorly understood at that time. 

I the descriptive approach, which typically utilises only the point estimates of the appropriate statistical parameter and compares to the pre-defined acceptance limits (Boulanger et al., 2003 Hartmann et al., 1998). Typical acceptance limits are 2% for the relative bias and 3% for the RSDIP (Bouabidi et al., 2010),... 

De Fontenay, G. Analytical method transfer New descriptive approach for acceptance criteria definition. J. Pharm. Biomed. Anal., 46, 2008, 104-112. 

This area has been the subject of recent extensive reviews,590-592 which deal particularly with the physical and theoretical aspects. In this section, a more chemical and descriptive approach will be adopted. 

Analysis of changes in in-vivo- and m-v/tro-synthesised proteins is a very descriptive approach to understanding the phenomenon of cold acclimation and cold tolerance. For a functional analysis a molecular dissection of the process is required. This will allow investigators to determine the level (transcriptional/translational) at which the appearance of the new mRNAs is regulated, and the sequence information of the cold-regulated genes should point to the biochemical features of the encoded proteins. 

The committee concludes that descriptive approaches are often important in laying a foundation on which risk-based approaches can build. The interpretative power of risk-based approaches varies widely, depending on the information available. To improve the interpretation of biomonitoring results, an expansion of the scientific database on many chemicals is needed. 

Another descriptive approach characterizes a chemical s use pattern in society at large. The information is used to interpret biomonitoring data in terms of how long the chemical may have been detected in bodily fluids and whether its concentration may be going up or down with changing use. It is not uncommon for the public to consider a new biomarker as evidence of new exposure. But it is possible that exposure has been going on for de-... 

The most data-intensive approaches are those which evaluate the risk associated with a biomonitoring result. Evaluation of risk may be a desirable outcome, given the importance of the How risky is this blood concentration question and the fact that the descriptive approaches only provide relative information and do not assess risk. Figure 5-2 illustrates the various risk-based options discussed in the report. 

This chapter identifies a variety of approaches for interpreting biomonitoring results, ranging from descriptive to risk-based. The descriptive approaches are useful as a first step in analyzing biomonitoring data, but they do not describe the level of risk. That requires the risk-based approaches... 

The committee drew the following conclusions about descriptive approaches ... 

Descriptive approaches are important in laying a foundation that risk-based approaches can build from, and in some cases they are the only type of analysis needed. 

In order to underpin these more general descriptive approaches to migration by appropriate physico-chemical arguments, the parameters controlling migration will be presented and discussed in more depth in the following chapter. 

We note from all this prior work that structure at the macro, micro, nano and molecular levels of organisation will all be important. Secondly, the properties of the composite food product will not be related simply to a list of its components (the recipe), since different structural forms can be assembled from the same components by different processes. Emphasis on structure and its origin discriminates food materials science from the former descriptive approach of formulation/process empiricism embodied in most recipes. 

Both the simple descriptive approach and the group theory approach to hybridization are used in the following example. 

One common element shared by a number of the analyses of laboratory data that we have described is that the magnitude of change from the start to the end of the study is important, but so is the final value itself. In addition, the relative frequency of such outcomes is of vital interest when gauging the overall risk of treatment with a new drug. One descriptive approach to address several of these issues is a graphical one. 

The descriptive approach to entropy adopted here is adequate for the isothermal processes chosen as examples. It is not easy, for example, to visualize the change of entropy which occurs when two bodies at differing temperatures come into thermal... 

The success of these classifications is a direct result of the adoption of a descriptive approach to the definition of mental disorders, more or less consciously emulating the scientific basis of disease classification in physical medicine.If mental illnesses are physical diseases, why is there a need to emulate the scientific basis of disease classification in physical medicine The need to emulate isprima facie evidence that mental illnesses are not diseases. Nevertheless, Fulford maintains Once illness and disease are clearly distinguished, however, it becomes possible to compare like with like, mental illness ... 

The heat evolved by friction at the interface of two rubbing bodies passes by conduction into the material of both. The resulting interfacial temperature at equilibrium is a function of specific parameters such as the coefficient of friction, the loading force, the velocity of sliding, the dimensions of the interface, the properties of the materials, etc. The classical theory of heat conduction has been applied to the interfacial temperature problem with good to moderate success. The calculations are often so intricate that the physical picture is lost in the complexity therefore our introductory consideration of interfacial temperature will be the simplified descriptive approach immediately following. 

Koltermann, C. E. Gorelick, S. M. (1996) Heterogeneity in sedimentary deposits A review of structure-imitating, process-imitating and descriptive approaches. Water. Resour Res. 32(9), 2617-2658. 

In this chapter, will be presented some of the principles that are most applicable to predict the behavior of biological systems. For this, a descriptive approach will be used that minimizes quantitative considerations. However, the science of physics can also help to determine how much the biological system is influenced by its physical environment. 

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