A parallel genetic algorithm for the Steiner Problem in Networks

This paper presents a parallel genetic algorithm to the Steiner Problem in Networks. Several previous papers have proposed the adoption of GAs and others metaheuristics to solve the SPN demonstrating the validity of their approaches. This work differs from them for two main reasons: the dimension and the characteristics of the networks adopted in the experiments and the aim from which it has been originated. The reason that aimed this work was namely to build a comparison term for validating deterministic and computationally inexpensive algorithms which can be used in practical engineering applications, such as the multicast transmission in the Internet. On the other hand, the large dimensions of our sample networks require the adoption of a parallel implementation of the Steiner GA, which is able to deal with such large problem instances.

Modelling disease spread and control in networks: implications for plant sciences

Networks are ubiquitous in natural, technological and social systems. They are of increasing relevance for improved understanding and control of infectious diseases of plants, animals and humans, given the interconnectedness of today's world. Recent modelling work on disease development in complex networks shows: the relative rapidity of pathogen spread in scale-free compared with random networks, unless there is high local clustering; the theoretical absence of an epidemic threshold in scale-free networks of infinite size, which implies that diseases with low infection rates can spread in them, but the emergence of a threshold when realistic features are added to networks (e.g. finite size, household structure or deactivation of links); and the influence on epidemic dynamics of asymmetrical interactions. Models suggest that control of pathogens spreading in scale-free networks should focus on highly connected individuals rather than on mass random immunization. A growing number of empirical applications of network theory in human medicine and animal disease ecology confirm the potential of the approach, and suggest that network thinking could also benefit plant epidemiology and forest pathology, particularly in human-modified pathosystems linked by commercial transport of plant and disease propagules. Potential consequences for the study and management of plant and tree diseases are discussed.

Ethics education in management accounting studies: evidence from business schools in Ghana

Management accounting in recent times, and perhaps rightly so, has begun to gain recognition as a profession separate and complimentary to financial accounting. Evidence exists to suggest that management accountants are exposed to a unique set of ethical challenges within industry and that a significant high number of management accountants have engaged in unethical practices in performing their jobs. For the accounting profession as a whole, the growing number of corporate failures has created a credibility crisis that requires a deliberate intervention to mitigate. If this is not addressed sooner, the accounting profession stands the risk of losing relevance. Scholarship on ethical issues in accounting practice have either focused mostly on financial accounting or have sought to combine ethical issues for financial and management accounting. Various arguments have been made in recent times of the need to treat ethical issues in behavioural studies as context-specific and therefore separate ethical considerations in management accounting from financial accounting. This study adopts an approach, following various literature, that effective ethics education can help practitioners deal appropriately with ethical issues at the work place, and explores students’ and faculty members’perceptions on current practices in ethics education. As expected, faculty and students differ significantly on a wide range of issues on ethics education in management accounting. Based on the insights provided from this study, appropriate recommendations have been made to improve ethics education in management accounting.

Mapping power law distributions in digital health social networks: methods, interpretations, and practical implications

BACKGROUND: Social networks are common in digital health. A new stream of research is beginning to investigate the mechanisms of digital health social networks (DHSNs), how they are structured, how they function, and how their growth can be nurtured and managed. DHSNs increase in value when additional content is added, and the structure of networks may resemble the characteristics of power laws. Power laws are contrary to traditional Gaussian averages in that they demonstrate correlated phenomena. OBJECTIVES: The objective of this study is to investigate whether the distribution frequency in four DHSNs can be characterized as following a power law. A second objective is to describe the method used to determine the comparison. METHODS: Data from four DHSNs—Alcohol Help Center (AHC), Depression Center (DC), Panic Center (PC), and Stop Smoking Center (SSC)—were compared to power law distributions. To assist future researchers and managers, the 5-step methodology used to analyze and compare datasets is described. RESULTS: All four DHSNs were found to have right-skewed distributions, indicating the data were not normally distributed. When power trend lines were added to each frequency distribution, R(2) values indicated that, to a very high degree, the variance in post frequencies can be explained by actor rank (AHC .962, DC .975, PC .969, SSC .95). Spearman correlations provided further indication of the strength and statistical significance of the relationship (AHC .987. DC .967, PC .983, SSC .993, P<.001). CONCLUSIONS: This is the first study to investigate power distributions across multiple DHSNs, each addressing a unique condition. Results indicate that despite vast differences in theme, content, and length of existence, DHSNs follow properties of power laws. The structure of DHSNs is important as it gives insight to researchers and managers into the nature and mechanisms of network functionality. The 5-step process undertaken to compare actor contribution patterns can be replicated in networks that are managed by other organizations, and we conjecture that patterns observed in this study could be found in other DHSNs. Future research should analyze network growth over time and examine the characteristics and survival rates of superusers.

The social relations of business representation and devolved governance in the United Kingdom

The reform of regional governance in the United Kingdom has been, in part, premised on the notion that regions provide new territories of action in which cooperative networks between business communities and state-agencies can be established. Promoting business interests is seen as one mechanism for enhancing the economic competitiveness and performance of 'laggard' regions. Yet, within this context of change, business agendas and capacities are often assumed to exist 'out there, as a resource waiting to be tapped by state institutions. There is little recognition that business organisations' involvement in networks of governance owes much to historical patterns and practices of business representation, to the types of activities that exist within the business sector, and to interpretations of their own role and position within wider policymaking and implementation networks. This paper, drawing on a study of business agendas in post-devolution Scotland, demonstrates that in practice business agendas are highly complex. Their formation in any particular place depends on the actions of reflexive agents, whose perspectives and capacities are shaped by the social, economic, and political contexts within which they are operating. As such, any understanding of business agendas needs to identify the social relations of business as a whole, rather than assuming away such complexities.

Pattern separation in digital learning nets

Pattern separation is a new technique in digital learning networks which can be used to detect state conflicts. This letter describes pattern separation in a simple single-layer network, and an application of the technique in networks with feedback.

Problematising accounting for biodiversity

Purpose – This paper seeks to problematise “accounting for biodiversity” and to provide a framework for analysing and understanding the role of accounting in preserving and enhancing biodiversity on Planet Earth. The paper aims to raise awareness of the urgent need to address biodiversity loss and extinction and the need for corporations to discharge accountability for their part in the current biodiversity crisis by accounting for their biodiversity-related strategies and policies. Such accounting is, it is believed, emancipatory and leads to engendering change in corporate behaviour and attitudes. Design/methodology/approach – The authors reviewed the literature relating to biodiversity across a wide array of disciplines including anthropology, biodiversity, ecology, finance, philosophy, and of course, accounting, in order to build an image of the current state of biodiversity and the role which accounting can and “should” play in the future of biodiversity. Findings – It is found that the problems underlying accounting for biodiversity fall into four broad categories: philosophical and scientific problems, accountability problems, technical accounting problems, and problems of accounting practice. Practical implications – Through establishing a framework problematising biodiversity, a roadmap is laid out for researchers and practitioners to navigate a route for future research and policymaking in biodiversity accounting. It is concluded that an interdisciplinary approach to accounting for biodiversity is crucial to ensuring effective action on biodiversity and for accounting for biodiversity to achieve its emancipatory potential. Originality/value – Although there is a wealth of sustainability reporting research, there is hardly any work exploring the role of accounting in preserving and enhancing biodiversity. There is no research exploring the current state of accounting for biodiversity. This paper summarises the current state of biodiversity using an interdisciplinary approach and introduces a series of papers devoted to the role of accounting in biodiversity accepted for this AAAJ special issue. The paper also provides a framework identifying the diverse problems associated with accounting for biodiversity.

MAC protocols and mobility management module for healthcare applications using Wireless Sensor Networks

Using Wireless Sensor Networks (WSNs) in healthcare systems has had a lot of attention in recent years. In much of this research tasks like sensor data processing, health states decision making and emergency message sending are done by a remote server. Many patients with lots of sensor data consume a great deal of communication resources, bring a burden to the remote server and delay the decision time and notification time. A healthcare application for elderly people using WSN has been simulated in this paper. A WSN designed for the proposed healthcare application needs efficient Medium Access Control (MAC) and routing protocols to provide a guarantee for the reliability of the data delivered from the patients to the medical centre. Based on these requirements, the GinMAC protocol including a mobility module has been chosen, to provide the required performance such as reliability for data delivery and energy saving. Simulation results show that this modification to GinMAC can offer the required performance for the proposed healthcare application.

Materiality, subjectification, and government: the geographies of Britain's Motorway Code

In this paper I provide a critical discussion of Foucault's work on government and governmentality. I argue that geographers have tended to overlook the ways in which practices of self-government and subjectification are performed in relation to programmes of government, and suggest that they should examine the technical devices which are embedded in networks of government. Drawing upon these observations I suggest how geographers might proceed, tracing the geographies of a specific artefact: the British government's 1958 Motorway Code. I examine how the code was designed to serve as a technology of government that could shape the conduct of fairly mobile and distant subjects, enabling them to govern their conduct and the movements of their vehicles.

Efficient tree construction for the multicast problem

A new heuristic for the Steiner Minimal Tree problem is presented here. The method described is based on the detection of particular sets of nodes in networks, the “Hot Spot” sets, which are used to obtain better approximations of the optimal solutions. An algorithm is also proposed which is capable of improving the solutions obtained by classical heuristics, by means of a stirring process of the nodes in solution trees. Classical heuristics and an enumerative method are used CIS comparison terms in the experimental analysis which demonstrates the goodness of the heuristic discussed in this paper.

Efficient tree construction for the multicast problem

A new heuristic for the Steiner minimal tree problem is presented. The method described is based on the detection of particular sets of nodes in networks, the “hot spot” sets, which are used to obtain better approximations of the optimal solutions. An algorithm is also proposed which is capable of improving the solutions obtained by classical heuristics, by means of a stirring process of the nodes in solution trees. Classical heuristics and an enumerative method are used as comparison terms in the experimental analysis which demonstrates the capability of the heuristic discussed

Response of the EAA FRSC to the EFRAG/ANC/FRC discussion paper: 'Towards a Disclosure Framework for the Notes'

We summarise the response of the EAA’s FRSC to Towards a Disclosure Framework for the Notes, a Discussion Paper (DP) issued jointly by EFRAG, ANC and FRC. While supportive of much of the DP, and in particular of the underlying aim to place disclosures on a sounder conceptual foundation, we identify two broad themes for further development. The first concerns the DP’s diagnosis of the problem, which is that the existing financial reporting is characterised by, on the one hand, disclosure overload and, on the other hand, an absence of a conceptual framework for organising and communicating disclosures. Our review of the literature suggests much greater support for the second of these two factors than for the first. The second broad theme is the purpose of the proposed DF, and the principles that are derived from this purpose. Here, we stress the need for the framework to better accommodate the context within which financial statement disclosures are used. In practice, this context is characterised by variation in information, incentives and enforcement, each of which has a considerable effect on the appropriate disclosure policy and practice in any given situation.