Variational Bayes model averaging for graphon functions and motif frequencies inference in <Emphasis Type="Italic">W</Emphasis>-graph models

W-graph refers to a general class of random graph models that can be seen as a random graph limit. It is characterized by both its graphon function and its motif frequencies. In this paper, relying on an existing variational Bayes algorithm for the stochastic block models (SBMs) along with the corresponding weights for model averaging, we derive an estimate of the graphon function as an average of SBMs with increasing number of blocks. In the same framework, we derive the variational posterior frequency of any motif. A simulation study and an illustration on a social network complete our work.     

Capturing the benefits of industry 4.0: a business network perspective

Abstract

This study uses a business network perspective to investigate the industry 4.0 context with the internet of things (IoT) as its enabling technology and product-use data as its core network resource. A three-stage qualitative methodology (interviews, focus group, Delphi-based inquiry) was used to examine the case of an emergent IoT-based business network in the UK road transport industry to examine: (i) how aspects of product use data influence the benefit opportunities the data provide to the different network actors; (ii) how capturing of the benefit opportunities in a network context is impacted by key barriers; and (iii) how network capabilities can overcome these barriers to capture benefits from product-use data. The study, thereby, contributes to an understanding of the industry 4.0 context from a resource dependency theory perspective and provides concrete recommendations for management operating in this context.     

What Makes Better Boards? A Closer Look at Diversity and Ownership

This study investigates the joint effect of corporate ownership and board of directors' diversity configurations on the success of strategic merger and acquisition (M&A) decisions. Board diversity is defined as the extent to which its demographic diversity as measured by the culture, nationality, gender and experience of its directors complements its statutory diversity. A theoretical framework linking ownership, board diversity and M&A strategic decision making is proposed and tested. Based on a sample of 289 M&A decisions undertaken by Canadian firms over the period 2000–2007, demographic diversity is found to have a clear and non‐linear effect on M&A performance while statutory diversity is of limited influence. Ownership is found to influence the effect of diversity, making the relation finer and more precise. This has practical implications. First, statutory diversity is not sufficient for well‐performing boards. Also, ownership is an important factor. The most advocated board diversity aimed at insuring the board's independence is not valid across all ownership configurations. From a public policy perspective, results provide support for the principles‐based approach in governance. Governance regimes should encourage the search for a balance between board diversity and the need for cohesion that best serves the firm's purpose and obligations.     

Explaining the Causes and Effects of Dynamic Capabilities Generation: A Multiple‐Indicator Multiple‐Cause Modelling Approach

The purpose of this paper is to develop a multiple‐indicator multiple‐cause model to explain dynamic capabilities generation. We use one of the main common effects of dynamic capabilities (operational, structural and strategic flexibility) to design a measurement tool for dynamic capabilities generation. Based on this measurement tool, we test the influence of several factors identified in the specialized literature as potential causes that trigger and promote dynamic capabilities generation. We use data from a survey of 200 CEOs of Spanish firms to test the model. The results show that only organizations whose managers have perceived a high degree of environmental dynamism have generated dynamic capabilities. The results also show that knowledge codification and technical innovation are significantly related to dynamic capabilities generation. We attempt to shed light on current theoretical debates about dynamic capabilities generation and provide a practical guide to explain the origin and results of dynamic capabilities that have been tested empirically.     

Urbanization does not affect green space bird species richness in a mid-sized city

Urban Ecosystems - Urbanization is one of the most intensive forms of landscape and habitat transformation, resulting in species loss, and taxonomic and functional homogenization of different...     

Incidence of Social Accountability in Local Governance: The Case of the Network for Fair,Democratic and Sustainable Cities and Territories in Latin America

VOLUNTAS: International Journal of Voluntary and Nonprofit Organizations - In Latin America, the emergence of a series of civil society initiatives aimed at citizen engagement for social...     

Promoting Individual and Social Changes: A Hybrid Model of Social Work with Groups

Taking as a starting point two influential, yet different approaches in group work, that is, the self-directed group work and mutual aid models, this article examines a possible alternative for conducting social work with groups. Drawing from structuration theory, which makes a strong dialectical relation between agency and structure possible, this article highlights how our alternative model could lead to a greater integration of the micro- and macrodimensions in group-work practice. The Discussion section proposes three key principles for group work, namely, a belief in people’s strengths and capacities, a focus on critical thinking, and a concern for the development of a democratic culture in groups. These principles are conveyed through the group worker’s roles as consciousness raiser and process facilitator and provide a flexible and participatory process that can be used with a broad range of service-user groups. The article concludes with a discussion on the strengths and limitations of the model.     

Estimation of the Intensity Parameter of the Germ‐Grain Quermass‐Interaction Model when the Number of Germs is not Observed

The Quermass‐interaction model allows to generalize the classical germ‐grain Boolean model in adding a morphological interaction between the grains. It enables to model random structures with specific morphologies, which are unlikely to be generated from a Boolean model. The Quermass‐interaction model depends in particular on an intensity parameter, which is impossible to estimate from classical likelihood or pseudo‐likelihood approaches because the number of points is not observable from a germ‐grain set. In this paper, we present a procedure based on the Takacs–Fiksel method, which is able to estimate all parameters of the Quermass‐interaction model, including the intensity. An intensive simulation study is conducted to assess the efficiency of the procedure and to provide practical recommendations. It also illustrates that the estimation of the intensity parameter is crucial in order to identify the model. The Quermass‐interaction model is finally fitted by our method to P. Diggle's heather data set.     

An extension of the generalized half-normal distribution

In this paper we propose an extension of the generalized half-normal distribution studied in Cooray and Ananda (Commun Stat 37:1323–1337, 2008). This new distribution is defined by considering the quotient of two random variables, the one in the numerator being a generalized half normal distribution and the one in the denominator being a power of the uniform distribution on \((0,1)\) , respectively. The resulting distribution has greater kurtosis than the generalized half normal distribution. The density function of this more general distribution is derived jointly with some of its properties and moments. We discuss stochastic representation, maximum likelihood and moments estimation. Applications to real data sets are reported revealing that the proposed distribution can fit real data better than the slashed half-normal, generalized half-normal and Birnbaum–Saunders distributions.