what-when-how
In Depth Tutorials and Information
sociotechnical power grids (Byres and Lowe, 2005), and security technology and
practice assessments (Byres and Franz, 2006). In this topic we will devote a key
chapter to sociotechnical network security.
1.5.2 Resilience
Resilience is defined as the ability of a system to maintain or recover its service
delivery in the face of major external disruptions. Given the criticality of socio-
techncial networks such as the power grid, the Internet, transportation networks,
telecommunication networks, etc., in the proper functioning of society, the resil-
ience of such systems in the face of various kinds of external shocks is critical. he
resilience of sociotechnical networks is a function of their vulnerability as well as
adaptive capacity (Omer et al., 2009). he less the vulnerability, the lower the pos-
sibility that sociotechnical network performance will be compromised. he more
the adaptive capacity of the system, the faster will the system jump back to its
initial performance levels after being affected by a shock. Sociotechnical network
resilience can increase when diversity, redundancy, modularity, and cognition/
autonomy are designed into the system.
1.5.3 Reliability
Network reliability refers to the reliability of the overall network to provide commu-
nication in the event of failure of a component or a set of components in the network
(
WileyEncyclopediaofElectricalandElectronicsEngineering
, 1999). For sociotechnical
networks, the reliability expands to all three layers, namely, the physical/technological
network layer, the data communication layer, and the social/institutional layer. he
main challenge is to define the holistic reliability of the sociotechnical network, given
that the reliability of each network layer cannot be easily combined with that of the
other layers. his is due to the diferences in the fault modes and the asynchronous
nature of failures within the components within each layer (physical, data, social).
1.5.4 Distributed versus Centralized Control
In sociotechnical networks the physical or virtual connections are controlled either
through a single network controller or through several controllers. he former is
called centralized control, and the latter is known as decentralized control. In a
sociotechnical network, distributed control systems are more common, as different
parts of the system will have different types of control actions and would be distrib-
uted over jurisdictional and geographical boundaries. Issues of local versus global
optimization for larger-scale sociotechnical networks are fundamental systems-level
decisions that need to depend on the organization and structure of the social net-
work layer and on the economic optimization of locally managed networks as well as
other system attributes and properties such as reliability, resilience, and security.
