Four new chapters of the resource are now available:

Requirements Engineering
from an HCI Perspective
by Alistair G. Sutcliffe
The chapter is structured in six sections. In the section 13.1, the Requirements Engineering process is described. This is followed in section 13.2 by a review of scenario-based approaches which illustrate the convergence between Requirements Engineering and HCI. Section 13.3 deals with models and representations in the two disciplines, then section 13.4 returns to a process theme to assess the differences between HCI and Requirements Engineering approaches to development. Section 13.5 reviews how knowledge is reused in the requirements and design process, leading to a brief discussion of the prospects for convergence between HCI and Requirements Engineering.

Context-Aware Computing
Context-Awareness, Context-Aware User Interfaces, and Implicit Interaction
by Albrecht Schmidt
In this chapter, we introduce the basics for creating context-aware applications and discuss how these insights may help design systems that are easier and more pleasant to use

Disruptive Innovation
by Clayton M. Christensen
A disruptive technology or disruptive innovation is an innovation that helps create a new market and value network, and eventually goes on to disrupt an existing market and value network. The term is used in business and technology literature to describe innovations that improve a product or service in ways that the market does not expect. Although the term disruptive technology is widely used, disruptive innovation seems a more appropriate term in many contexts since few technologies are intrinsically disruptive; rather, it is the business model that the technology enables that creates the disruptive impact.

Open User Innovation
by Eric von Hippel
Almost 30 years ago, researchers began a systematic study of innovation by end users and user firms. At that time, the phenomenon was generally regarded as a minor oddity. Today, it is clear that innovation by users, generally openly shared, is a very powerful and general phenomenon. It is rapidly growing due to continuing advances in computing and communication technologies. It is becoming both an important rival to and an important feedstock for producer-centered innovation in many fields. In this chapter, I provide an overview of what the international research community now understands about this phenomenon.