NETWORKS

Networks are particular types of human relations or technological creations, sometimes compared to systems and webs, that establish unique exchanges between human beings and spaces. Since the 1700s, and especially since the invention of the Internet, networks have been subject to scientific analysis. Insofar as they define or influence human behavior they may be subject to ethical assessment.

Network Types and Influences

In mathematics a network is commonly defined as a directed graph with vertices (or nodes) and weighted edges (also called arcs or links). As such networks come in different structural types: bus, ring, star (hub and spoke), mesh (web), and more (see Figure 1). Networks can be further distinguished in terms of numbers of vertices and edges. Each structure has its own intrinsic properties, which can be enhanced or modified by giving different weights or strengths to the various links, as when (for instance) one link in a star network is weighted more heavily than another.

Throughout history networks have provided the foundation and infrastructure for humans to conduct wide-ranging economic and social activities. Well-known physical networks in which nodes correspond to locations in space and links to appropriate connections with associated flows include transportation and communication networks. Transportation networks have evolved over the centuries through advances in science and technology and come in a myriad of forms: road, rail, air, or waterway, with a variety of associated modes of travel. They traverse physical distances to facilitate business transactions, military conquest, and visits among colleagues, clients, friends, and family, as well as enabling people to explore new areas and to expand horizons. Communication networks, in turn, allow exchanges of information not only within communities but also across regions and national boundaries by means of postal services, telephones, radio, television, computers, satellites, and microwaves that carry written messages, video, and/or electronic data. Energy networks, as another example, provide the necessary fuel to support many transportation and communication network transactions.

In addition, more abstract networks such as financial networks, a variety of logistical networks (e.g., supply chains), as well as knowledge and social networks (based on transportation and communication networks) play new and not yet completely understood roles in societies and economies. The reliability, efficiency, and accessibility of such networks enhance production and distribution, facilitate the exchange of information and knowledge, and add to the diversity and richness of goods and services. At the same time, the structure of such networks and the connectivity provided by them may yield insights and advantages for particular individuals and organizations.

Organizations today, be they local, regional, national, or global in scope and as diverse as businesses, educational institutions, or governments, are highly dependent on networks, which are becoming increasingly interrelated. Indeed, individuals may now be able to conduct financial transactions electronically and to shop globally from their places of employment and have the products delivered to the desired destinations. They may also, in certain circumstances, be able to work from home or other chosen locations depending on the management of the underlying networks, their utilization and availability, and the auxiliary ethical character of network designs, accessibility, and usage.

Fascinatingly, the structure of social relationships may also be represented as a graph/network, and the study of social relationships has given rise to the multidisciplinary topic of social network analysis. In such a context, important measures include the number of connections for an individual (represented by nodes in the network), the strength of these connections, the centrality of various individuals, and the existence of cliques and subgroups. Moreover, one can calculate the degrees of separation. Clearly, the existence and structure of social networks also affects the usage of physical networks, notably transportation and various communication networks. The latter networks, in turn, play pivotal roles in the evolution of social networks.

The Science of Networks

The topic of networks and network management dates to ancient times with classical examples including the publicly provided Roman road network and the time-of-day chariot policy, whereby chariots were banned from the ancient city of Rome during particular times of the day (Nagurney 2000). The topic of networks as a subject of scientific inquiry originates in a 1736 paper by the Swiss mathematician Leonhard Euler (1707–1783), which is considered the earliest paper on graph theory, where a graph in this context is meant as an abstract or mathematical representation of a system by its depiction in terms of vertices (nodes) and edges (or arcs) connecting various pairs of vertices.

Interestingly, not long thereafter, François Quesnay (1694–1774), in his Tableau économique (1758), conceptualized the circular flow of an economy as a network. Gaspard Monge (1746–1818), who had worked under Napoleon Bonaparte in providing the infrastructure support for his army, published what is probably the first paper on the transportation network model in 1781. Much later, and following the first book on graph theory by Dénes König in 1936, works by the economists Leonid V. Kantorovich (1939), Frank L. Hitchcock (1941), and Tjalling C. Koopmans (1947) considered the network flow problem associated with the classical transportation problem. Thus the study of network flows, primarily in a transportation context, preceded the development of even optimization theory and such elegant algorithmic techniques as the simplex method (see Dantzig 1948).

Indeed, the emergence and evolution of a plethora of physical networks over space and time, coupled with realizations of the importance of abstract networks, and the effects of human decision-making on networks through their utilization and management, has given rise to the development of rich and powerful theories that are rigorous, scientific, and network-based. The novelty of networks lies in that they are pervasive and fundamental and provide the fabric for the connectivity of societies and economies. At the same time, methodologically, network theory has developed into a powerful and dynamic medium for abstracting complex network-based problems. Many contemporary networks (including the Internet) are characterized by a large-scale structure, complexity of interconnections and interrelationships, congestion, and distinct behavior of the users. One illustrative phenomena is the Braess paradox (1968), in which the addition of a new road in a transportation network—or a link in a communications network such as the Internet (see Korilis, Lazar, and Orda 1999)—makes all users of the network worse off. Methodologies for the formulation and analysis of network systems are thus of wide practical significance (see Ahuja, Magnanti, and Orlin 1993; Nagurney 1999; Nagurney and Dong 2002).

Today it is possible, through advances in scientific models, theories, and computational tools, to predict optimal routes on networks from different origins to destinations both from a system-optimized perspective, in which there is a central controller of the network flows, and from a user-optimized one, in which users of the network select their optimal routes in what may be viewed as a selfish manner (see Beckmann, McGuire, and Winsten 1956; Dafermos and Sparrow 1969; Nagurney 1999; Nagurney and Dong 2002). In addition, it is possible to optimize financial portfolios from a network perspective (Nagurney and Siokos 1997; Nagurney 2003), to predict the profit-maximizing production and shipment patterns between tiers of network decision-makers (Nagurney and Dong 2002), and to even determine information flows in an organization (Wu et al.).

More recently, social networks have been integrated with economic networks, in the form of supply chains, through the theory of supernetworks (see Walkobinger and Nagurney 2004) in order to capture relationship levels as flows in addition to product shipments. Such complex networks not only synthesize and integrate the structure of the underlying social and economic relationships but also capture human behavior and decision-making and the associated impacts. Moreover, the dynamics of the interactions between the various decision makers as well as how their relationships evolve over time (and how they compete and/or cooperate) can be modeled, along with the optimal product flows and prices.

There are nevertheless many questions of ethical significance concerning networks, their operation and management, and their accessibility and usage.

Accessibility and Ethics

In regard to accessibility, consider transportation and communication networks. Accessibility concerns the design of the network itself. The number of nodes and the number of links connecting the nodes determine the network topology, whereas the quality of the links affects the ultimate accessibility and usage. For example, well-built roads will support travel and trade, whereas an impoverished transportation network infrastructure can seriously impede development and growth. At the same time, the availability of alternative modes of transportation may enhance employment because workers can reach their (possible) places of work. Similarly, those who cannot drive or cannot afford car ownership may be able to use cost-appropriate transportation modes (if such are available).

The interrelationships between networks in this context also have ethical implications. For example, it is now well-established that transportation and especially vehicular transportation on congested urban networks not only results in a loss of productivity but has serious consequences for the environment because of pollution emissions (Nagurney 2000). Moreover, these emissions are not necessarily local but are often transported over political boundaries. Hence, the choices made by an individual in terms of route/mode selection can negatively affect distant populations. Although there may be economic approaches to ameliorating some of these negative effects through, for example, tolls or pollution charges, there may also be incentives put in place that appeal to humans' individual sense of ethics.

In terms of communication networks, notably the Internet, the accessibility issue has received a great deal of attention especially from a variety of government organizations. Indeed, terms such as the digital divide have become part of the popular lexicon. In certain fields, particularly science, the essentialness of accessibility to the Internet for research, information, and knowledge dissemination is well known (Alberts; Newman 2001). Less emphasized and as important is to increase the connectivity in less-developed and developing nations, which not only may have poor communication infrastructures but may suffer from substandard energy networks, as well.

Not only do scientists benefit from accessibility to communication networks such as the Internet, but educational systems throughout the globe can only be enriched through reliable and efficient Internet connections.

Usage and Ethics

Increased access to interconnected networks also raises ethical issues. For example, given that information on individuals can be retrieved in seconds by anyone with appropriate computer connections, there are serious questions concerning privacy of the information and the right of individuals to check the correctness of the data and information concerning themselves. Moreover, the regulation of the content of what is circulating on the Internet, given its huge and immediate reach, is a subject of both ethical and legal importance. In addition, such computer-based crimes as hacking and computer piracy are examples of illegal and unethical usage of communication networks. Such activities can have serious financial as well as personal consequences (see, e.g., UNESCO).

The Internet, by helping to span the globe and enhancing people's right to communicate, has given freedom to many voices. It has played a major role in social and economic transformations and has helped in the internationalization of trade, especially through electronic commerce and the globalization of nations' economies. In addition, the Internet has allowed new social networks to evolve, oftentimes between individuals and among groups who have never even met face-to-face. Freedom, however, must come with responsibility, a sense of ethics, and solid judgment of the consequences of one's actions on others. Never has the subject of networks and ethics been more timely and relevant.

ANNA NAGURNEY

SEE ALSO Communication Ethics;Computer Ethics;Digital Divide;Information Society;Internet;Radio;Roads and Highways;Telephone.

BIBLIOGRAPHY

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INTERNET RESOURCES

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