Centralized Structure Research Articles

Structural centrality in fuzzy social networks based on fuzzy hypergraph theory

The knowledge of key network members is generally known to be critical to fuzzy social network analysis. Thus far, most studies aiming to identify critical members have taken network structural centrality measures. Since fuzzy graph cannot effectively depict the multidimensional relationships between the nodes of fuzzy social networks, a fuzzy social network model is developed complying with a mathematical theory of fuzzy hypergraph, allowing fuzzy social network to be represented more intuitively and visually. A fuzzy hypergraph model of fuzzy social network refers to a structure, vertex set acts as an object set, and the fuzzy relation in fuzzy relation structure is expressed by membership function and fuzzy relation matrix. With the fuzzy hypergraph model of fuzzy social networks, the definitions of structural centrality are given (i.e., degree centrality, relative degree centrality, closeness centrality, relative closeness centrality, betweenness centrality and relative betweenness centrality). Lastly, by analyzing examples, the process of building fuzzy social network with fuzzy hypergraph and the calculation method of centrality are illustrated.

P0730ALTERATION OF BRAIN CONNECTIVITY IN NEUROLOGICALLY ASYMPTOMATIC PATIENTS WITH CHRONIC KIDNEY DISEASE

Abstract Background and Aims Our previous study demonstrated that patients in End stage renal disease had decreased structural and functional brain connectivity, and there was significant association between brain connectivity and cognitive function. The aim of this study was to evaluate the alterations of structural and functional connectivity using graph theoretical analysis in the neurologically asymptomatic patients with relatively early stage chronic kidney disease (CKD). Method We prospectively enrolled neurologically asymptomatic 20 patients with CKD stage 3 and 20 healthy controls, and all of the subjects underwent diffusion tensor imaging (DTI) and resting state functional MRI (rs-fMRI). Using data from the structural and functional connectivity matrix based on DTI and rs-fMRI, we calculated network measures, including global efficiency, local efficiency, mean clustering coefficient, characteristic path length, and small-worldness index, and investigated the differences between the patients with CKD and healthy controls. Results The patients with CKD had altered global structural connectivity and preserved functional connectivity compared to healthy controls. The all of the measures of global structural connectivity were significantly different between the patients with CKD and healthy controls. However, all of the measures of global functional connectivity in the CKD patients were not different from those in healthy participants. In the CKD patients, the functional betweenness centrality of the right insular cortex, right occipital pole, and right thalamus was significantly different from that in healthy subjects. The structural betweenness centrality of the left calcarine, right posterior cingulum was significantly different from that in healthy subjects. Conclusion There were significant alterations of global structural connectivity between patients with CKD and control. However, functional connectivity of brain network was preserved in contrast to ESRD patients.

Anarchic manufacturing: Distributed control for product transition

Manufacturers are poorly equipped to manage product transition scenarios, when moving from one product to another. Most tools consider a mature system, yet during transition and ramp up disturbances and inefficiency are common. The traditional methods, using centralised planning and control structures are too rigid and often resort to simple dispatch heuristics in this highly dynamic environment. Distributed systems have been proposed to leverage their self-organising and flexible traits to manage highly volatile and complex scenarios.Anarchic manufacturing, a free market based distributed planning and control system, delegates decision-making authority and autonomy to system elements at the lowest level; this system has previously been shown to manage job and flowshop style problems. The system has been adapted to use a dynamic batching mechanism, where jobs cooperate to benefit from economies of scale. The batch enables a direct economic viability assessment within the free market architecture, whether an individual machine should changeover production to another product type. This profitability assessment considers the overall system state and an agent’s individual circumstance, which in turn reduces system myopia. Four experiments, including a real-world automotive case study, evaluate the anarchic manufacturing system against two centralised systems, using three different ramp-up curves. Although not always best performing against centralised systems, the anarchic manufacturing system is shown to manage transition scenarios effectively, displaying self-organising and flexible characteristics. The hierarchical system was shown to be impeded by its simplifying structure, as a result of structural rigidity.

Cultural policy, the public sphere, and public libraries: a comparison of Norwegian, American, and Japanese models

ABSTRACT This study compares cultural policy, public libraries, and the public sphere in Norway, the United States, and Japan. Results of the comparison indicate that Norway emphasizes physical meeting spaces and the public sphere. In Japan, there is more emphasis on the literary public sphere. Norway and Japan have strong centralized governance structures, which influence how public libraries function in the public sphere. In the US, cultural policy administration is more diffuse and local. There is not an explicit national cultural policy related to public libraries. In the US, legitimation of public libraries in the public sphere is strong and occurs locally. Public libraries in the US are used less as public sphere infrastructure and more for educational and recreation purposes. The results of this comparison are significant for understanding public libraries and the public sphere from an international cultural policy perspective.

A game-theoretic method for resilient control design in industrial multi-agent CPSs with Markovian and coupled dynamics

Multi-agent cyber-physical systems (CPSs) are ubiquitous in various modern critical infrastructures, especially in industrial automation control involved in the petrochemical, metallurgy, textile, and pharmaceutical, which are vulnerable for their hierarchically and horizontally interconnected architecture. In this paper, we investigate a resilient control design problem for industrial multi-agent CPSs of centralised information structure, with Markovian and physically coupled dynamics from a game-theoretic perspective. First, we investigate a worst-case design problem and solve for worst-case disturbance strategy and optimal disturbance attenuation level parameter through an equivalent two-person zero-sum differential game in both finite- and infinite-horizon. Second, we study a corresponding N-person worst-case nonzero-sum differential game and derive state-feedback Nash equilibrium solution of robustness property as resilient control strategy for each agent. The experimental case study is given to demonstrate that using resilient control strategy, each agent could maintain its physical plant operationally normal under cyber attack, malicious disturbance input and physical state interdependency.

Of Circuits and Brains: The Origin and Diversification of Neural Architectures

Nervous systems are complex cellular structures that allow animals to interact with their environment, which includes both the external and the internal milieu. The astonishing diversity of nervous system architectures present in all animal clades has prompted the idea that selective forces must have shaped them over evolutionary time. In most cases, neurons seem to coalesce into specific (centralized) structures that function as “central processing units” (CPU): “brains”. Why did neural systems adopt this physical configuration? When did it first happen? What are the physiological, computational, and/or structural advantages of concentrating many neurons in a specific place within the body? Here we examine the concept of nervous system centralization and factors that might have contributed to the evolutionary success of this centralization strategy. In particular, we suggest a putative scenario for the evolution of neural system centralization that incorporates different strands of evidence. This scenario is based on some premises: 1/ Receptors originated before neurons (sensors before transmitters) and there were deployed in the first organisms in an asymmetric fashion (deposited randomly in the outer layer); 2/ Receptors were segregated in a preferential position in response to an anisotropic environment 3/ Neurons were born in association with this receptors and used to transmit signals distally; 4/ Energetics preferentially selected the localization of neurons, and synapsis, close to the receptors (to minimize wire use, for instance); 5/ The presence of condensed areas of neurons could have stimulated the proliferation of more receptors in the vicinity, increasing the repertoire of signals processed in an specific body domain (i.e. head) plus contributing to amplify the computational power of the neuronal aggregate); 6/ The proliferation of receptors would have induced the proliferation of more neurons in the aggregate, with a further increase in its computational power (hence, diversifying the behavioural repertoire). These last two steps of proliferation and aggregation could have been sustained through a feedback loop, reiterated many times, generating distinct topologies in different lineages. Our main aim in this paper is to examine the brain as both a biological and a physical or computational device.

The growth of hidden champions in China: a cognitive explanation from integrated view

PurposeThere is a research gap in strategic management regarding the complement from managerial cognition literature to the behavioral theory of firm, as well as linkage between cognitive structure and cognitive process of strategy formulation in the field of managerial cognition, which also calls for further exploration. The purpose of this paper is to construct a model from an integrated view for explaining the process of cognitive reconstruction under incremental changes.Design/methodology/approachQualitative research is conducted in the form of 17 semi-structured interviews in four hidden champions operating in China. Based on the model generated from the literature review, this paper adopts the abductive logic for data analysis.FindingsThis paper draws the following conclusions. The cognitive structure is shaped by the changing environment and the performance feedback, the variance in structural attributes will affect whether the changing environment destructs the effectiveness of original cognitive structure or not, the centrality of cognitive structure will promote the efficiency of tried-and-true organizational adaptations to incremental changes, and cognitive structure reconstruction is the result of the recursive process of trial-and-error learning.Originality/valueThis paper proposes the model explaining the interaction mechanisms between cognitive structure and strategy formulation process. It also presents the iterative sense-making process for reconstructing cognitive structure in strategy formulation. Both of them extend the understanding on managerial cognition in organizational adaptations to incremental environmental changes.

Financial Leverage and Dividend Policy: Evidence from Oil and Gas Firms in Nigeria

Aims: The study examined the relationship existing between financial leverage and the dividend policy of quoted oil and gas firms in Nigeria.
 Study Design: The research work adopted for the study ex-post facto research design. Secondary data spanning 2011 to 2018 was sourced and collated from annual reports and accounts of oil and gas firms in Nigeria and Nigeria Stock Exchange factbook.
 Place of Study: Department of Accountancy, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria.
 Methodology: The data was analyzed employing descriptive statistics and the least square regression technique.
 Results: The study revealed that a significant relationship exists between long term debt and dividend payout ratio; total debt and dividend payout ratio while no significant relationship exists between short term debt and dividend payout ratio of quoted oil and gas firms in Nigeria
 Conclusion: Given the integral role the Oil and Gas sector plays in Nigeria, this paper showed the centrality of the capital structure and dividend policy in ensuring the stability of corporations in the Nigerian Oil and Gas industry.

Identifying the spatial distribution of public transportation trips by node and community characteristics

ABSTRACTIdentifying the spatial distribution of travel activities can help public transportation managers optimize the allocation of resources. In this paper, transit networks are constructed based on traffic flow data rather than network topologies. The PageRank algorithm and community detection method are combined to identify the spatial distribution of public transportation trips. The structural centrality and PageRank values are compared to identify hub stations; the community detection method is applied to reveal the community structures. A case study in Guangzhou, China is presented. It is found that the bus network has a community structure, significant weekday commuting and small-world characteristics. The metro network is tightly connected, highly loaded, and has no obvious community structure. Hub stations show distinct differences in terms of volume and weekend/weekday usage. The results imply that the proposed method can be used to identify the spatial distribution of urban public transportation and provide a new study perspective.

Social network analysis as a tool for the analysis of the international trade network of aquatic products

Social network analysis (SNA) is an efficient method to describe network characteristics from various specific aspects. In this study, it took world countries (areas) as the primary units of analysis and introduced different procedures of SNA, including network density, centrality, and core-periphery structure, and applied them to the field of international aquatic product trade (IAPT). Besides statistical and descriptive analysis, the paper made full use of tools as Ucinet 6.3 and ArcGIS 10.2 to conduct visualized analysis, which would be more convenient and clear for demonstrating network structure of IAPT. With aim of figuring out the overall structure features, the important countries (areas) as the center roles, and the core-periphery structure in the network from both spatial and temporal perspective, data on international aquatic products in the period 2008–2017 was used in SNA. Above all, a special part was that a comparison analysis was given in the paper by comparing the results of IAPT with the general trade network, showing how different was the network of IAPT from the general trade network. The paper found that the IAPT network became increasingly dense from 2008 to 2017 despite of a relatively low level of density for the long period. Countries distributed mainly in the northern areas of North America, Europe, and east and south Asia dominated the whole IAPT network in the most periods of 2008–2017, while most of those distributed in South America, southern areas of the North America, Africa, and western Asia consistently served as the weak in IAPT network. Moreover, core-periphery structure did exist in IAPT network. And the network outcomes of IAPT were similar to a general one in some aspects.

Structures for care and silenced topics: accomplishing gender-based violence prevention education in a primary school

ABSTRACT Little is known about the conditions that enable teachers to educate others about the troubling issue of gender-based violence. This paper discusses the centrality of structures for care for fostering the willingness and capacity of primary school teachers to initiate classroom talk about this sensitive and silenced issue. Drawing on interviews conducted over 3 years with five teachers and two leaders in a primary school in a culturally and religiously diverse community in Melbourne, Australia, barriers to teaching about gender diversity, gender-based violence and family violence are discussed. This includes teachers’ and leaders’ anxiety about triggering distress and fears about parental backlash. School-level structures that enabled action in the face of challenge are identified, including committed leadership, collaborative organisational culture, ongoing in-house professional learning, compassionate collegial relationships and proactive programme provision. We discuss the implications for those supporting school-wide interventions.

Social centralization and semantic collapse: Hyperbolic embeddings of networks and text

Modern advances in transportation and communication technology from airplanes to the internet alongside global expansions of media, migration, and trade have made the modern world more connected than ever before. But what does this bode for the convergence of global culture? Here we explore the relationship between centralization in social networks and contraction or collapse in the diversity of semantic expressions such as ideas, opinions and tastes. We advance formal examination of this relationship by introducing new methods of manifold learning that allow us to map social networks and semantic combinations into comparable hyperbolic spaces. Hyperbolic representations natively represent both hierarchy and diversity within a system. In a Poincaré disk—a two-dimensional hyperbolic embedding—radius from center traces the position of an actor in a social hierarchy or an idea in a semantic hierarchy. Angle of the disk required to inscribe connected actors or ideas captures their diversity. We illustrate this method by examining the relationship between social centralization and semantic diversity within 21st Century physics, empirically demonstrating how dense, centralized collaboration is associated with a reduction in the space of ideas and how these patterns generalize to all modern scholarship and science. We discuss the complex of causes underlying this association, and theorize the dynamic interplay between structural centralization and semantic contraction, arguing that it introduces an essential tension between the supply and demand of difference.

The impact of carbon emissions tax on vertical centralized supply chain channel structure

This paper studies the supply chain channel structure which is considered choosing either centralization or decentralization in both a single chain system with a single product and a two chains system with competition in the two substitutable products under carbon emissions tax, respectively. In the two cases, each chain consists of a retailer, who acts as a follower and a manufacturer who acts as a leader. Our analytical results show that: (i) When decentralization is practicable, the government is willing to set a lower carbon tax. (ii) In a single-chain system, the monopolistic manufacturer is better off under decentralization than under centralization when its product emissions pollution is high enough. (iii) In the two chains system, two manufacturers can benefit from decentralization when their product is more emissions polluting. Under certain conditions, comparing with centralization, decentralization enhances two manufacturers’ profits through carbon emissions tax reduction and keeps consumer surplus and social welfare at the first-best level. (iv) The manufacturer’s product quantity under decentralization is lower than that under centralization due to double marginalization effect, which also results in the lower environmental pollution. Our study also suggests that for the seriously emissions polluter, when it utilizes decentralization, the government have to introduce a lower carbon emissions tax in the consideration of abating environmental pollution and of maximizing its profits. The result can also benefit policy-makers in instructing firms to choose decentralization for promoting social development and environmental protection.

Spatial linkage of volatility spillovers and its explanation across G20 stock markets: A network framework

This paper empirically estimates the spatial correlation relationship of volatility spillovers and its influencing factors across G20 stock market. We apply GARCH-BEKK model to estimate volatility spillover and construct dynamic volatility networks. The connectedness analysis shows that the spatial linkage of volatility spillover is time varying and has obvious multiple superposition phenomena. As somewhat innovation results, we use the factor analysis method to obtain centrality comprehensive indicators that can clearly depict the risk contagion intensity and risk acceptance intensity. In general, the developed markets are more influential than the emerging markets during periods of turbulence, and the emerging markets are more sensitive to volatility shocks than developed markets during any period. Finally, this paper introduces quadratic assignment procedure (QAP) method to identify the major factors that influence the spatial linkage of volatility spillovers. Results show that geography influences the volatility spatial correlation differently across economic cycles, and the centrality structure factors have greater impact on the spatial correlation than the external economic factors. The QAP regression analysis shows that these influencing factors can explain about 50% of the spatial correlation variation of international financial markets' volatility spillovers.

Unable to Lead, Unwilling to be Led: Contesting the Villainization of School Leadership Appointments in Cameroon

Cameroon operates two subsystems of education which have emerged from French and British Colonial rule (Tchombe, 2014). However, the French educational concepts of management in the school system dominate school leadership in Cameroon. In its current form, school leaders in state institutions are appointed by the state and view themselves as administrators and representatives of the state. Their practices are regulated by a centralized state control which allows them to be responsible for the implementation of national legislation and the ministry’s directives. School leaders, therefore, function as pedagogical and educative pilots of schools in a top-down approach (Ambassa et al. 2011). One of the challenges of this leadership approach is in the appointment of school leaders in various public schools. This paper uses an interdisciplinary approach to critique and contest the appointment of school leaders of state schools in an autocratic and centralized management structure. The study interrogates practices, policies, and outcomes of leadership appointments in a centralized state management structure. It posits competing tensions in the context of equality and equal opportunities for various educational actors in the school system. The study concludes that an unfair state policy of appointment of school leadership negatively impacts on meritocracy and elaborately builds a superclass of privileged education professionals whose focus is the advancement of allegiance and pacification of the political elite that appointed them. Key words: schools, leadership, meritocracy, centralised, particularism, universalism.

IEEE Access Special Section: Emerging Technologies for Energy Internet

Renewable energy sources such as photovoltaic (PV), wind, tidal, and ocean waves have increasingly penetrated the global production of energy. Energy Internet has been widely regarded as one of the promising solutions for the serious energy crisis and environmental pollution problem. Unlike the conventional centralized power generation structure, energy Internet widely utilizes different types of distributed generations (DGs), which are located closer to the user and generate electric power within distributed networks. Modular energy storage devices (ESDs) such as batteries for electric vehicles can effectively complement the function of DGs through bidirectional plug-and-play power interfaces. Thus, energy Internet has the ability to minimize power loss, enhance power quality, and improve system reliability.

Decentralised Centralism: Insights from a Malaysian Cluster School of Excellence

Currently, in many developing countries, there have been intensified efforts by policymakers to push for decentralisation of education as part of a neo-liberal reform agenda to improve school management efficiency and cater to localised needs. In the Malaysian context, the government has attempted further decentralisation of autonomy in selected public schools, marking a shift from the post-independence centralised education structure. This has led to the development of Cluster Schools of Excellence, practising some form of school-based management and accorded autonomy in the selection of niche areas, programme planning and programme implementation. Drawing primarily on the interview narratives from school administrators as key policy actors, this study examines how autonomy is manifested at the micro-level and how the school administrators exercise their agency when they are accorded autonomy. Using a decentralised centralism framework, the tensions and complexities in education policy implementation are highlighted in this study. Findings reveal that agency and autonomy are held by both macro and micro-level policy actors in varying degrees, and that school administrators have fundamental agency in school-level policy implementation. The study also explores the dynamics of the decentralisation process and raises the issue of re-centralisation of authority through decentralisation of education.

IEEE Access Special Section Editorial: Information Centric Wireless Networking With Edge Computing for 5G and IoT

The advent of the Internet of Things (IoT) and Fifth Generation (5G) high-speed communication networks are expected not only to make it necessary to rapidly increase the number of communication nodes and generate large amounts of data but also to change the nature of the network to a more dynamic environment. However, the present network structure and the operation methods have various problems that need to be solved in order to cope with the aforementioned changes. Some issues, for example, are Transmission Control Protocol/Internet Protocol (TCP/IP)-based and end-to-end-based centralized and rigid network structure, the lack and allocation difficulties of IP addresses, increasing network traffic forwarding massive data to the cloud at remote locations for high-capacity data processing, as well as increasing delays in receiving effective analytic results from the remote cloud server.

Hidden structure and value network: shedding light on position assessment

This study focuses on hierarchical structures of value networks of service systems. But how can the central and influential network positions be found in the value network? The position of actors is extracted using the hidden structure method (HSM) and centrality metrics of social network analysis (SNA). Both analyses apply adjacency matrix data that reveal direct dependencies of actors in a value network. We measured indegree, outdegree, betweenness, and closeness centralities to each actor to compare SNA and HSM results. HSM can reveal the actors who conduct the most significant activities, as well as more peripheral actors who have a strong influence on core actors. Thus, HSM does not neglect the hierarchy between actors. Our methodological contribution suggests that in parallel with widely used SNA centrality measures, researchers should leverage HSM to define influential actors. Two pharmacy concepts in Finland provide the empirical research context.

Blockchain-Enabled Integrated Market Platform for Contract Production

Contract production and transaction are very common and important since it can greatly reduce future uncertainty and is well-organized by buyers, sellers, and trusted third parties (TTPs). However, current commodity trading systems (such as spot, futures, and forward contract) are still traditional centralized structures, which means that there may always be concerned about the single point of failure and data corruption. Besides, even though there already exists fragmentary decentralized applications (DApps) for the marketplace, order management, resale, delivery, financing, and insurance, they are not integrated for operating contract production and transaction comprehensively. In this work, a blockchain-enabled integrated marketing platform (BeIMP) is proposed for contract production and transactions. BeIMP is a consortium blockchain (CsBc) framework that enables better safety, efficiency, and interoperability among stakeholders. BeIMP can directly match producers and consumers and reduce the problem of intermediaries’ improper market operation. BeIMP has a three-tier risk diversification mechanism. First, both parties can know the quantity and price according to the contract specification (CSpec) in advance to avoid future uncertainty. Second, the buyers can resell the established order if they need, thereby diversifying the risk. Third, the concept of insurance is introduced to reduce force majeure and other systemic risks. BeIMP can also help producers get the loan from the financial institution (FI) if they need fund for production. We implement and demonstrate the prototype in contract farming (CF) first and discuss its generalizability to other scenarios. Experiment results show that the smart contract (SC) function is stable enough and the proof of authority (PoA) has the advantage in throughput and can give users a better experience.