Consensus Formation Research Articles

Impact of temporal network structures on the speed of consensus formation in opinion dynamics

Opinion dynamics on networks has wide applications to empirical and engineered systems and profound prospects in the general study of complex systems. Many efforts have been devoted to understanding how opinion dynamics is affected by network topology. However, social interactions are best characterized as temporal networks in which ordering of interactions cannot be ignored. Temporal activity patterns including heterogeneous contact strength and interevent times, turnover edge/node dynamics, and daily patterns could have significant effects that would not be captured by static aggregate network representations. In this paper, we study the effects of such temporal patterns on the speed of consensus formation in various models of continuous opinion dynamics using four empirical data sets, including three human face-to-face networks from different real-world settings and a social insect interaction network. We find that static, aggregated networks consistently overestimate the speed of simulated consensus formation while weight heterogeneity associated with frequency of interactions has an inhibitory effect on consensus formation relative to the behavior on unweighted networks. Moreover, the speed of consensus formation is found to be highly sensitive to nodal lifetimes, suggesting that randomization protocols that dramatically alter the distribution of lifetimes cannot be relied upon as reference models. On the other hand, temporal patterns including burstiness of interevent times and the lifetime of edges are found to have insignificant effects on consensus formation. The sensitivity to nodal lifetimes is further demonstrated via synthetic networks generated by an activity-driven model with tunable nodal lifetimes.

Dynamics and control for multi-agent networked systems: A finite-difference approach

We analyze the dynamics of multi-agent collective behavior models and its control theoretical properties. We first derive a large population limit to parabolic diffusive equations. We also show that the nonlocal transport equations commonly derived as the mean-field limit, are subordinated to the first one. In other words, the solution of the nonlocal transport model can be obtained by a suitable averaging of the diffusive one. We then address the control problem in the linear setting, linking the multi-agent model with the spatial semi-discretization of parabolic equations. This allows us to use the existing techniques for parabolic control problems in the present setting and derive explicit estimates on the cost of controlling these systems as the number of agents tends to infinity. We obtain precise estimates on the time of control and the size of the controls needed to drive the system to consensus, depending on the size of the population considered. Our approach, inspired on the existing results for parabolic equations, possibly of fractional type, and in several space dimensions, shows that the formation of consensus may be understood in terms of the underlying diffusion process described by the heat semi-group. In this way, we are able to give precise estimates on the cost of controllability for these systems as the number of agents increases, both in what concerns the needed control time horizon and the size of the controls.

救急集中治療の終末期方針検討における多職種倫理カンファレンスの現状とクオリティーコントロール(Current situation and quality control from an inter–professional ethics conference on terminal policy discussions for acute disease and intensive care)

要旨【目的】救急集中治療の人生の最終段階（以下，終末期）における方針決定は倫理問題を抱えやすい。理由は突然発症し情報と時間的猶予が少ない，生命維持装置を駆使するため急性期と終末期の境界が不明瞭，意識障害などで患者が意向を示せないなどである。そのため当センターでは多職種倫理カンファレンス（inter–professional ethics conference: IPEC）を開催し，問題解決に取り組んできた。これまでに実施したIPECの内容を検証し，その有用性と課題を検討した。【対象】2016年1月1日から2018年3月31日の27か月間にIPECを行った39例。患者背景，IPEC開催日，検討メンバー，終末期の判断率，意思決定の方法，方針決定日と内容，転帰等を算出した。【結果】IPECは必要性が判断されるとほぼ同日のうちに開催された。初回のIPECで方向性が示されたのは77%であり，その後の患者家族との合意形成の過程で衝突がみられたケースはなかった。【結語】救急集中治療の現場では患者の状態変化が速く，方針決定には機動性と迅速性を要するため，IPECによる方針検討は有用であった。一方でその検討プロセスには質を確保することも重要であり，IPEC議事録兼進行マニュアルや意思決定能力評価シートといった標準化ツールなどによるクオリティーコントロールの可能性が示唆された。

Method of agents’ state estimation in multiresolution multiagent simulation

The paper proposes the multiagent techniques for approximation of agent’s state in the multiresolution multiagent simulation. The key methods we have used for state aggregation and disaggregation are: consensus algorithm and formation control. The idea of the coordination of multiple agents has emerged from both observation and simulation of a collective behavior of biological entities. The consensus algorithms are commonly used for the cooperative control problems in the multiagent systems, whilst the formation control is the most popular and fundamental motion coordination problem in the multiagent systems, where agents converge to predefined geometric shapes. The presented approach shows that multiagent methods seem to be very promising in multiresolution simulation. Consensus and formation control algorithms remove necessity to specify the much more complex algorithms for the aggregation and disaggregation needs.

Occupational health physicians' interventions based on the decision-making process for corporate health policies and company-employee needs: An exploratory study

The topic of occupational health physicians' specific interventions for deciding on corporate health measures has not been researched. Such interventions are necessary in corporate decision-making and for considering the needs of the company and its employees. We examined the aspects and methods of occupational health services that facilitate corporate decision-making regarding health measures. We conducted semi-structured interviews with 11 certified occupational health physicians involved in the planning of health measures at 10 companies. Data were analyzed qualitatively and inductively using Berelson's content analysis method. We divided 144 items corresponding to the research theme into three categories: organizational decision-making process in health measures, occupational health physician interventions, and complementary factors concerning interventions. The interventions were further categorized as follows: building relationships, promoting mutual understanding; consensus-building process, coordination; visualization company needs based on hypotheses; and integrated planning and proposals. The study identified specific intervention methods of each category. Aspects and methods that facilitate decision-making in occupational health services were as follows: 1) understanding the scope of consensus formation and its impact based on the characteristics of corporate decision-making regarding health measures and premises of decision maker; 2) improving awareness about occupational health by consistently presenting information on occupational health, translating it to be necessary for corporate management. Occupational health professionals, mainly occupational health physicians, are expected to contribute to health policy decisions while utilizing the method clarified in this study.

Majority-vote dynamics on multiplex networks with two layers

Majority-vote model is a much-studied model for social opinion dynamics of two competing opinions. With the recent appreciation that our social network comprises a variety of different ‘layers’ forming a multiplex network, a natural question arises on how such multiplex interactions affect the social opinion dynamics and consensus formation. Here, the majority-vote processes will be studied on multiplex networks with two layers to understand the effect of multiplexity on opinion dynamics. We will discuss how global consensus is reached by different types of voters: AND- and OR-rule voters on multiplex-network and voters on single-network system. The AND-model reaches the largest consensus below the critical noise parameter qc. It needs, however, much longer time to reach consensus than other models. In the vicinity of the transition point, the consensus collapses abruptly. The OR-model attains smaller level of consensus than the AND-rule but reaches the consensus more quickly. Its consensus transition is continuous. The numerical simulation results are supported qualitatively by analytical calculations based on the approximate master equation.

Influence and seepage: An evidence-resistant minority can affect public opinion and scientific belief formation

Some well-established scientific findings may be rejected by vocal minorities because the evidence is in conflict with political views or economic interests. For example, the tobacco industry denied the medical consensus on the harms of smoking for decades, and the clear evidence about human-caused climate change is currently being rejected by many politicians and think tanks that oppose regulatory action. We present an agent-based model of the processes by which denial of climate change can occur, how opinions that run counter to the evidence can affect the scientific community, and how denial can alter the public discourse. The model involves an ensemble of Bayesian agents, representing the scientific community, that are presented with the emerging historical evidence of climate change and that also communicate the evidence to each other. Over time, the scientific community comes to agreement that the climate is changing. When a minority of agents is introduced that is resistant to the evidence, but that enter into the scientific discussion, the simulated scientific community still acquires firm knowledge but consensus formation is delayed. When both types of agents are communicating with the general public, the public remains ambivalent about the reality of climate change. The model captures essential aspects of the actual evolution of scientific and public opinion during the last 4 decades.

Consensus Formation in the Shrinking Society－Spatial Control and Autonomy in the Era of Depopulation (Research Group on Consensus Formation) (Ⅱ).

Consensus Formation in the Shrinking Society－Spatial Control and Autonomy in the Era of Depopulation (Research Group on Consensus Formation) (Ⅱ).

Opinion formation on evolving and adaptive networks

Members in a social group may change over time: a new member is recruited; a current member stops his or her position; a candidate supersedes a member of the group. Here we investigate the effects of changes of nodes on the dynamics of opinion formation. In our model, opinion formation is in two stages. In the first stage, a network evolves through a voting process that is used to select agents to add into the network, to remove from the network or to be replaced by other agents. Special rules for the voting process are necessary in the first stage. We focus on two rules, namely, majority rule and random rule. In the second stage, opinion formation takes place. We find that the majority rule generally foster consensus formation in comparison to the random rule. We also investigate the effects of changes of agents on two-party systems, in which there are two parties and opinions of members in the same party are close to each other. In particular, the effects of diversity of opinions for two-party systems are studied. A counterintuitive finding is that the diversity of opinions, instead of hindering consensus formation, facilitates consensus formation.

Manager Interaction and the Formation of Strategic Consensus: The Moderation Effect of Manager Role

In the dynamic environment the role of middle managers is becoming increasingly important in strategic management. From the perspective of middle managers, Using the method of theoretical deduction, this thesis analyses the influence of interaction between top management team and middle managers on the formation of strategic consensus and the moderation effect of manager role on integrating the theories of top management team and middle managers. This study concludes that the more sufficient information exchange between top management team and middle managers, and the greater the cross-influence between top management team and middle managers, the higher the strategic consensus. And the participatory leadership of top management team and the active participation of middle managers play a positive moderating role in the relationship between managers' interaction and strategic consensus.

An Adaptive Distributed Consensus Control Algorithm Based on Continuous Terminal Sliding Model for Multiple Quad Rotors’ Formation Tracking

Distributed consensus formation tracking problem of slow convergence and low accuracy for multiple quad rotors are solved in this paper. Continuous nonsingular terminal sliding model algorithm (CNTSMA) under Inner-Outer loop control structure is considered to deal with the control problem of nonlinear, strong coupling and underactuated characteristic of a quad rotor. For better convergence and higher tracking accuracy, an adaptive algorithm (denoted by ACNTSMA) further focused on coupling of x and y directions, with sliding model observer (SMO) to compensate system disturbances and uncertainties is proposed. Furthermore, to solve the consensus formation tracking problem, a consensus control protocol under a full-connected topology based on ACNTSMA is proposed, including formation pattern consensus controller and formation distance consensus controller. Stability theory and simulation results prove the proposed control algorithm is able to accurately achieve the first-order (position and velocity) consensus for multiple quad rotors' formation tracking. Besides, stability analysis of the proposed consensus control protocol illustrates that all sliding modes with finite-time stability applicable to second-order integral models are supposed to be established. And the proposed controller also has better convergence and faster response speed with no chattering for trajectory tracking.

Proof-of-Search: Combining Blockchain Consensus Formation With Solving Optimization Problems

To address the large amount of energy wasted by blockchains, we propose a decentralized consensus protocol for blockchains in which the computation can be used to search for good approximate solutions to any optimization problem. Our protocol allows the wasted energy to be used for finding approximate solutions to problems submitted by any nodes (called clients). Our protocol works in a similar way to proof-of-work, and it makes nodes evaluate a large number of solution candidates to add a new block to the chain. A client provides a search program that implements any search algorithm that finds a good solution by evaluating a large number of solution candidates. The node that finds the best approximate solution is rewarded by the client. Our analysis shows that the probability of a fork and the variance in the block time with our protocol are lower than those in proof-of-work.

Leader-Follower Consensus Multi-Robot Formation Control Using Neurodynamic-Optimization-Based Nonlinear Model Predictive Control

This paper investigates a nonlinear-model-predictive-control (NMPC)-strategy-based distributed leader-follower consensus multi-robot formation system. The control objective of this system is to design a group of nonholonomic robots to converge into the desired geometric pattern and to track a designed path. A directed graph that specifies communication topology for the formation is given. A leader-follower consensus formation problem based on the mobile robot kinematic model is obtained, which is further reformulated into a constrained nonlinear minimization problem through the NMPC strategy. A general projection neural network (GPNN) is implemented to efficiently derive the optimal control inputs for the robots. The simulation results verify the effectiveness of the proposed formation algorithm.

How Does Active Participation Affect Consensus: Adaptive Network Model of Opinion Dynamics and Influence Maximizing Rewiring

In this paper we study the impact of active participation, or deliberately seeking out other agents with an aim of convincing them, on the dynamics of consensus formation. For this purpose, we propose an adaptive network model in which two processes shape opinion dynamics at interwoven time‐scales as follows: (i) agents adapt their opinions subject to influence from social network neighbours who hold opinions within a tolerance interval δ and (ii) agents rewire network connections with an aim of maximizing their own influence on overall system opinion. We study this system both in an endogenous setting, in which all agents are subject to influence and also attempt to maximize influence, and in a setting of exogenous control, in which external agents not subject to influence adaptively attempt to maximize their influence. In both settings we find three regimes of stationary opinion configurations: (i) for low δ a regime of two evenly balanced radicalized opinion clusters at the extremes of the opinion space, (ii) for intermediate δ a ’winner‐takes‐most’ regime of two unevenly sized radicalized opinion clusters, and (iii) for large δ a regime in which very low spread compromise consensus states can be reached. Comparing to adaptive processes of random and deliberately spread‐reducing rewiring, we demonstrate that in regime (iii) competitive influence maximization can achieve near‐minimal opinion spread within near‐optimal times. Further, we also show that competitive influence maximizing rewiring can reduce the impact of small influential minorities on consensus states.

An Analysis of Good Governance in the Health System

Context: Good governance has been discussed as a new concept for poverty alleviation and economic development by global organizations, but this concept has been neglected in the health system. Therefore, this study was conducted with the goal of analyzing good governance in the health system. Evidence Acquisition: This was a descriptive study with systematic review method conducted at the medical bases of Medline, Scopus, Elsevier, PubMed, Ovid, CINAHEL, ScienceDirect, Springer and Web of Science and after screening at different stages, articles were evaluated and analyzed with inclusion criteria. Results: Among 360 studies, 10 cases had inclusion criteria. Three out of ten studies had evaluated the aspects of good governance in the health system and seven cases were discussed in the study of governance frameworks of health systems. Conclusions: Despite the emphasis of this study, using eight dimensions of participation, including: Rule of law, transparency, accountability, equality, efficiency and effectiveness, responsibility and the formation of general consensus (consensus) in analyzing good governance of countries, designing a native model of good governance in the health system in different societies, is essential.

Comments on “Opinion Dynamics Driven by Various Ways of Averaging”

The two main findings in Hegselmann and Krause (Comput Econ 25:381–405, 2005), the theorem on opinion stabilization and the corollary on consensus formation, are built on partial abstract means (PAMs) with bounded confidence sets that are assumed to be continuous. However, we show that any PAM with bounded confidence sets cannot be continuous. The discontinuity of such PAMs threatens the validity of the main findings in Hegselmann and Krause (Comput Econ 25:381–405, 2005). Moreover, the condition that the corollary on consensus formation considers necessary and sufficient, under which agents will approach a consensus, is, in fact, not a sufficient condition. To resolve these issues, we provide a sufficient condition for PAMs with bounded confidence sets under which the theorem on opinion stabilization becomes valid. We also show that under this condition the condition in the corollary on consensus formation is necessary condition for agents to approach a consensus.

Abstract 16788: Anatomical Repair Can Be Facilitated by Three-Dimensional Cardiac Printing in the Patients With Double Outlet Right Ventricle

Introduction: Determination of optimal strategy between single ventricle palliation (SVP) versus left ventricular recruitment (LVR) as a systemic ventricle is challenging in the patients with complicated double outlet right ventricle (DORV). We sought that three-dimensionally printed cardiac models (3DM) may enables the surgeons to make an intuitive preoperative decision potentially in favor of LVR. Hypothesis: Use of 3DM can extend the candidates for LVR and improve surgical outcomes. Methods: We retrospectively reviewed the patients with DORV from Jan 2008 to Jun 2018 in single center. The patients with discordant atrioventricular (AV) connection, complete AV septal defect and atresia of AV valves were excluded. The patients without at least one of LVR precluding factors such as left or right ventricular hypoplasia, mitral valve (MV) or tricuspid valve (TV) straddling, TV interposition in potential baffle course, huge ventricular septal defect (VSD), multiple VSDs and remote VSD were excluded. All patients were divided in SVP or LVR group except two patients without clear determination of strategy. Finally, 100 patients were enrolled and since 2016, 3DM was made in the patients with LVR precluding anatomy for better consensus formation whether LVR could be feasible in 26 patients. Risk factor analysis was done for SVP and adverse outcome. Results: Thirty-five patients enrolled as SVP strategy (Fontan operation in 14, Kawashima operation in 1, interstage mortality in 12, follow-up loss in 3 and waiting scheduled operation in 5) and 65 patients enrolled as LVR strategy (complete anatomical correction in 50, one and half ventricle repair in 6 and waiting scheduled operation in 9). In multivariate analysis, LV hypoplasia ( P =0.003) and MV straddling ( P =0.015) were significant LVR precluding factors and the use of 3DM was a favorable factor for LVR ( P =0.039, OR=0.212). Risk factor for mortality were LV outflow tract obstruction ( P =0.006) and LV hypoplasia ( P =0.043). The use of 3DM did not reach statistical significance on mortality ( P =0.132). Conclusions: In DORV patients, LVR can be precluded especially with LV hypoplasia and MV straddling however, LVR can be facilitated by direct-vision driven preoperative decision about complicated features with 3DM.

The social dimension in energy landscapes

If, nowadays, the Communities’ welfare lies in new expressions of collaboration between different types of subjects for the achievement of common objectives, cultural consensus becomes the collective transformation tool to promote regeneration interventions of life contexts encouraged by new social innovation ideas such as products, services and models. This research considers five aspects of the social dimension to define energy systems location and their acceptability. In particular: social equity: as a fair distribution of costs and risks throughout society; spatial equity: as a fair distribution of risks and costs throughout the territory; intergenerational equity: as a proper assessment of the risks that would entail current locations for future generations; procedural equity: when the location decisions and the same decision making process are perceived as legitimate by all concerned; equity structural: when the localization process involves all aspects and interests, leaving no one out for their approaches (Murphy and Stanley 2006). In relation to the analyzed aspects, this study suggests a point of view on the role of reasoning and interpreting the social activity of individuals in relation to bottom-up decision-making processes for the formation of cultural consensus when changes in the usual life and environmental contexts occur.

Hybrid Framework for Consensus in Directed and Asynchronous Network of Non-Holonomic Agents

This letter presents a hybrid systems strategy for consensus (or formation realization) for a fleet of nonholonomic agents. In the proposed model, each agent has a smooth continuous-time dynamics and a piecewise constant impulsive reference. The jumps on the reference trajectory take place at some updating instants that are decided independently by each agent. The jumps computation is based on the relative distance with respect to some time-varying neighbors at the update instants. Between the updates of its reference each robot will track its own constant reference trajectory. Our results provide consensus (formation realization) as far as a minimum dwell-time condition between consecutive updates is satisfied. A numerical example illustrates the theoretical results.

Consensus-Based Odor Source Localization by Multiagent Systems.

This paper presents an investigation of the task of localizing an unknown source of an odor by heterogeneous multiagent systems. A hierarchical cooperative control strategy has been proposed as a potential candidate to solve the problem. The agents are driven into consensus as soon as the information about the location of source is acquired. The controller has been designed in a hierarchical manner of group decision making, agent path planning, and robust control. In group decision making, the particle swarm optimization algorithm has been used along with the information of the movement of odor molecules to predict the odor source location. Next, a trajectory has been mapped using this predicted location of source, and the information is passed to the control layer. A variable structure control has been used in the control layer due to its inherent robustness and disturbance rejection capabilities. Cases of movement of agents toward the source under consensus and parallel formation have been discussed. The efficacy of the proposed scheme has been confirmed by simulations.