Network Literature (network + literature)

Distribution by Scientific Domains

Selected Abstracts

Spatial independent component analysis of functional MRI time-series: To what extent do results depend on the algorithm used?

Fabrizio Esposito
Abstract Independent component analysis (ICA) has been successfully employed to decompose functional MRI (fMRI) time-series into sets of activation maps and associated time-courses. Several ICA algorithms have been proposed in the neural network literature. Applied to fMRI, these algorithms might lead to different spatial or temporal readouts of brain activation. We compared the two ICA algorithms that have been used so far for spatial ICA (sICA) of fMRI time-series: the Infomax (Bell and Sejnowski [1995]: Neural Comput 7:1004,1034) and the Fixed-Point (Hyvärinen [1999]: Adv Neural Inf Proc Syst 10:273,279) algorithms. We evaluated the Infomax- and Fixed Point-based sICA decompositions of simulated motor, and real motor and visual activation fMRI time-series using an ensemble of measures. Log-likelihood (McKeown et al. [1998]: Hum Brain Mapp 6:160,188) was used as a measure of how significantly the estimated independent sources fit the statistical structure of the data; receiver operating characteristics (ROC) and linear correlation analyses were used to evaluate the algorithms' accuracy of estimating the spatial layout and the temporal dynamics of simulated and real activations; cluster sizing calculations and an estimation of a residual gaussian noise term within the components were used to examine the anatomic structure of ICA components and for the assessment of noise reduction capabilities. Whereas both algorithms produced highly accurate results, the Fixed-Point outperformed the Infomax in terms of spatial and temporal accuracy as long as inferential statistics were employed as benchmarks. Conversely, the Infomax sICA was superior in terms of global estimation of the ICA model and noise reduction capabilities. Because of its adaptive nature, the Infomax approach appears to be better suited to investigate activation phenomena that are not predictable or adequately modelled by inferential techniques. Hum. Brain Mapping 16:146,157, 2002. © 2002 Wiley-Liss, Inc. [source]

A Taxonomy of Supply Networks

Christine M. Harland
SUMMARY There has been limited research into how different types of supply networks can be created and operated. This article develops a taxonomy of supply networks with a particular focus on managing network creation and operation. The taxonomy is based on a review of network literature from various academic perspectives and extensive empirical data across a variety of industry sectors including automotive, fast-moving consumer goods, electronics, pharmaceuticals, and communications technologies. The main differentiating factors for classifying a matrix of four types of supply network are found to be the degree of supply network dynamics and the degree of focal company supply network influence. Network characteristics and different patterns ofnetworking activities are identified for each type of supply network. [source]

Policy networks and policy change in organic agriculture: a comparative analysis of the UK and Ireland

Alan Greer
This paper takes a comparative case,study approach, located within the literature on policy networks, to organic agriculture policy in the United Kingdom and Ireland since the late 1980s. An examination of policy development for the organic sector focuses primarily on regulatory arrangements. The core of the analysis applies some prominent themes in the policy network literature to the organic sector: the debate about sectoral and sub,sectoral networks, the relationship between networks, context and outcomes, and the role of the state and ideas in promoting policy change. [source]

The Tangled Webs of Westminster and Whitehall: The Discourse, Strategy and Practice of Networking Within the British Core Executive

Colin Hay
In this paper we identify and seek to resolve a certain paradox in the existing litera-ture on networks and networking. Whilst earlier policy network perspectives have tended to emphasize the structural character of networks as durable, dense and relatively static organization forms, the more recent strategic network literature emphasizes the flexible, adaptive and dynamic quality of networking as a social and political practice. However, neither perspective has yet developed a theory of network formation, evolution, transformation and termination. In this paper, we seek to rectify this omission, advancing a ,strategic relational' theory of network dynamics based on a rethinking of the concept of network itself. We illustrate this perspective with respect to the policy process centred in and around Westminster and Whitehall, drawing on a series of semi-structured interviews with ministers and officials from four departments. [source]

Wicked Problems, Knowledge Challenges, and Collaborative Capacity Builders in Network Settings

Edward P. Weber
Networks have assumed a place of prominence in the literature on public and private governing structures. The many positive attributes of networks are often featured,the capacity to solve problems, govern shared resources, create learning opportunities, and address shared goals,and a literature focused on the challenges networks pose for managers seeking to realize these network attributes is developing. The authors share an interest in understanding the potential of networks to govern complex public, or "wicked," problems. A fundamental challenge to effectively managing any public problem in a networked setting is the transfer, receipt and integration of knowledge across participants. When knowledge is viewed pragmatically, the challenge is particularly acute. This perspective, the authors argue, presents a challenge to the network literature to consider the mind-set of the managers,or collaborative capacity-builders,who are working to achieve solutions to wicked problems. This mind-set guides network managers as they apply their skills, strategies, and tools in order to foster the transfer, receipt, and integration of knowledge across the network and, ultimately, to build long-term collaborative problem-solving capacity. [source]

The Relative Importance of Interfirm Relationships and Knowledge Transfer for New Product Development Success,

Mette Praest Knudsen
The relationship and network literature has primarily focused on particular partner types, for example, buyer,supplier relationships or competitor interaction. This article explores the nature and relative importance of different types of interfirm relationships for new product development (NPD) success. The underlying premise of the study is that not only the type of interfirm relationships but also the combination of relationships are important for NPD performance. The interaction with a specific type of partner is expected to influence innovative performance by means of appropriate knowledge transfer. Varying needs for external knowledge, and thus types of relationships, are observed depending on the particular stages in the NPD process, the character of the knowledge base of the firm, and the industrial conditions. The absorption of external knowledge is discussed using the degree of redundancy in knowledge, which is defined as the degree of overlap in the knowledge base of the sender and the recipient of knowledge. Hence, the degree of redundancy has direct implications for the ease and, hence, use of knowledge shared with an external partner. The article is based on data from the Know for Innovation survey on innovative activities among European firms, which was carried out in 2000 in seven European countries covering five industries. The article explores the extent of use of external relationships in collaborative product development and finds that customers are involved more frequently in joint development efforts. Second, the industry association of the most important relationship is studied, and the results show that firms tend to partner with firms from their own industry. The danger in this approach is that firms from their own industry tend to contribute similar knowledge, which ultimately may endanger the creation of new knowledge and therefore more radical product developments. The analyses combine the finding that relationships with customers are used most frequently at both early and late stages of the product development process, with a second and more contradictory finding that at the same time customer relationships have a negative impact on innovative success. Moreover, the combination of customers, with both universities and competitors, has a significant negative effect on innovative performance. The potential causes of this apparent paradox can be narrowed down to two: (1) the average customer may be unable to articulate needs for advanced technology-based products; and (2) the average customer may be unable to conceptualize ideas beyond the realm of his or her own experience. Based on this evidence the article cautions product development managers to think explicitly about what certain customers can contribute with and, more importantly, to match this contribution directly with their own sense of what direction product development should go in the future. Finally, the role of complementary as well as supplementary knowledge is investigated for innovative success finding that sharing of supplementary knowledge with external partners in NPD leads to a positive effect on innovative performance. The article is concluded by a discussion of the implication of this finding for building knowledge within the firm and for selecting external partners for NPD. [source]

Searching for the Mecca of finance: Islamic financial services and the world city network

AREA, Issue 1 2010
David Bassens
This paper presents an analysis of the geography of the booming ,Islamic financial services' (IFS) sector, which provides a host of financial services based on Islamic religious grounds. The relevance of such an analysis is discussed against the conceptual backdrop of the world city network literature. It is argued that a focus on the globalisation of the IFS sector may provide an alternative to hegemonic geographical imaginations of world city-formation through its focus on other forms of globalising economic processes and regions that do not commonly feature in this literature. Based on information on the location strategies of 28 leading IFS firms in 64 cities across the world, we analyse different features of this decentred global urban geography. Manama is hereby identified as the Mecca of the IFS sector, while other major Gulf cities such as Dubai and Abu Dhabi are also primary nodes in this urban network. Other major Middle East North Africa (MENA) cities such as Tehran follow suit, but also more traditional financial centres such as London are well connected. [source]

Confucian Capitalism and the Paradox of Closure and Structural Holes in East Asian Firms

Sun-Ki Chai
abstract A long-standing debate has taken place in the organizational sociology and social network literatures about the relative advantages of network closure versus structural holes in the generation of social capital. There is recent evidence that these advantages differ across cultures and between East Asia and the West in particular, but existing network models are unable to explain why or address cultural variation in general. This paper seeks to provide a solution by integrating a culture-embedded rational model of action into the social network model of structure, using this not only to re-examine the closure versus structural hole debate, but also to tie it to the literature on Confucian capitalism and the ,East Asian Model' of the firm. We argue that this integrated approach allows us to systematically analyse the relationship between culture and behaviour in networks and, more specifically, to explain why closure has been a more powerful source of productivity in East Asia than the West. [source]