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This chapter will cover a general discussion of changes and improvement in software systems. Nearly all such systems are today programmed; that is, all the steps that the software should perform are specified ahead of time by the programmer. There are three areas of exception to that overwhelmingly usual practice: the first is an increasing (although still comparatively minute) effort still called machine learning; a second is a popular but ill-defined practice termed neural networks; and the third is evolutionary computation (or genetic algorithms), the kind that was invented by John Holland and which has been gathering momentum and success for some time. This chapter will focus on some special aspects of that evolutionary process, and we propose extensions to those techniques and approaches. The basic idea is to regard each evolutionary unit as a control structure; we then build complexity by controlling each unit with others, each subject to continuing adaptation and learning. The essence of the control unit is its triple soul in a kind of feedback loop: it has a power to act, that is, to exert some choice of action; it has a sensor to perceive and filter the response that is external to it; and it must evaluate that response to generate and influence its next control action. The general evolutionary or genetic system uses but a single evolutionary feedback—life on earth, for example, considers "survival" as its primary feedback. Here the generational improvements reside in the genotype, and are merely expressed in the individual organisms that are the successive programs. This chapter stresses the concept of control by evolving units; the essence of the control is the establishment of evaluation functions in other units. It is then useful to consider each evaluation function as a lower-level purpose. A piece of evolutionary software, in this way of looking at it, is then a complex expression of a purpose structure, and all the units evolve with separate and usually different purposes. The conceptual and linguistic vocabularies must then be established to deal with the many different kinds and levels of purposes. Higher-level purposes can be as general as moral values, and the lowest ones may be merely setpoints that control where muscles or motors are trying to go.

This chapter aims to provide you with the knowledge to be able to take an evidence-based approach to the nursing management of people who are experiencing pain. As a practising nurse, pain will be something that many of your patients will experience; however, one individual’s pain may be very different from another person’s. Pain can vary depending on the circumstances in which it is experienced and the individual characteristics of the person experiencing it. Understanding someone’s pain experience is therefore challenging because you cannot see someone’s pain or easily judge how bad it is, what it feels like, or how it affects him or her. This chapter provides you with knowledge and skills to recognize, assess, and manage the patient’s experience of pain effectively with evidence-based strategies. The variability of the experience of pain makes defining pain difficult. Pain is something that we have all experienced at some point in our lives and therefore, through these experiences, we have developed an understanding of what we consider to be pain. One of the most widely accepted definitions is that of the International Association for the Study of Pain (IASP), which defines pain as:…An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage. (Merskey and Bogduk,1994)…Although this definition is often quoted, the difficulty in defining pain is illustrated by the fact that the IASP added a note (go to http://www.iasp-pain.org/ and search for ‘pain definitions’) to highlight the individual nature of pain and the fact that pain is a sensory experience with an emotional component. The individual nature of pain is also highlighted by another commonly used definition:…Pain is whatever the experiencing person says it is and happens whenever he/she says it does. (McCaffery, 1972)…This definition highlights the fact that pain is an individual experience and that measuring pain objectively is difficult. Therefore asking the person and actively listening to the self-report of the experience is the best way in which to understand another person’s pain. A common criticism of McCaffery’s definition is that some people cannot say what they are experiencing.