Explicit Coordination Research Articles

Stigmergic coordination in FLOSS development teams: Integrating explicit and implicit mechanisms

The vast majority of literature on coordination in team-based projects has drawn on a conceptual separation between explicit (e.g. plans, feedback) and implicit coordination mechanisms (e.g. mental maps, shared knowledge). This analytic distinction presents some limitations in explaining how coordination is reached in organizations characterized by distributed teams, scarce face to face meetings and fuzzy and changing lines of authority, as in free/libre open source software (FLOSS) development.Analyzing empirical illustrations from two FLOSS projects, we highlight the existence of a peculiar model, stigmergic coordination, which includes aspects of both implicit and explicit mechanisms. The work product itself (implicit) and the characteristics under which it is shared (explicit) play an under-appreciated role in helping software developers manage dependencies as they arise. We develop this argument beyond the existing literature by working with an existing coordination framework, considering the role that the codebase itself might play at each step. We also discuss the features and the practices to support stigmergic coordination in distributed teams, as well as recommendations for future research.

Distributed Power Allocations in Heterogeneous Networks With Dual Connectivity Using Backhaul State Information

Long Term Evolution (LTE) release 12 proposes the use of dual connectivity in heterogeneous cellular networks, where a user equipment (UE) maintains parallel connections to a macrocell base station and to a low-tier node such as a picocell base station or relay. In this paper, we propose distributed multi-objective power control where each UE independently adapts its transmit power on its dual connections, where the uplinks could be of unequal bandwidth and have non-ideal backhaul links. In the proposed optimization, the UEs dynamically switch between data rate maximization and transmit power minimization as the backhaul load varies. To address the coupling between interference and the backhaul load, we propose a low-overhead convergence mechanism which does not require explicit coordination between UEs and also derive a closed-form expression of the transmit power levels at equilibrium. Simulation results show that our scheme achieves higher aggregate end-to-end data rate and significant power saving in comparison to a scheme that employs a greedy algorithm and a scheme that employs only waterfilling.

Complexation of Sm3+ and pamidronate: A DFT study

We reported a quantum mechanical study of the complexes formed between Sm3+ and the bisphosphonate ligand pamidronate in aqueous solution. According to available experimental pKa values pamidronate was expected to exist in aqueous solution, at physiologically relevant pH, in its di- and tri-protonated forms (denoted by H3L and H2L). The most stable structures of the ligands and Sm3+ complexes were found by using a detailed analysis of the conformational space with semiempirical and DFT methods. The results showed that both H2L and H3L bisphosphonates acted as a tridentate ligands in their complexes with Sm3+. The addition of explicit water molecules to the coordination sphere of the metal not only gave different coordination numbers for H2L and H3L complexes (CN=9 and 10), but also provided different trends in stabilization energies. The results highlighted the importance of considering not only an explicit first coordination shell, but also a second hydration shell, for an adequate description of this type of complexes in aqueous solution.

Rethinking the ‘mirroring’ hypothesis: implications for technological modularity, tacit coordination, and radical innovation

Studies of the ‘mirroring’ hypothesis have demonstrated the relationships between technological modularity and explicit coordination, yet little is known about the ‘mirroring’ relationship between technological modularity and tacit coordination, and how the ‘mirroring’ relationship may affect radical innovation. This paper contributes to the ‘mirroring’ hypothesis by identifying the interaction mechanisms embedded in and surrounded over the mirroring relationships. Using survey data of 121 high‐tech firms in China, our study indicates that technological modularity enhances interfirm tacit coordination between module‐makers (‘mirroring’ hypothesis), and will also positively influence radical innovation (‘outcome’ hypothesis). Moreover, tacit coordination negatively moderates the impact of technological modularity on radical innovation (‘interaction’ hypothesis), indicating that the ‘mirroring’ relationship may offset the benefit obtained from modularization. It also suggests that, in a high‐technology industry in underdeveloped areas, tacit coordination could lead to exposure of hidden knowledge, thus lowering module‐makers' motivation for technology breakthrough.

Vertical Restraints Facilitating Horizontal Collusion: ‘Stretching’ Agreements in a Comparative Approach

This article discusses the approaches of the European Union (EU) and of the United States (US) to the notions of agreement and concerted practice applied to horizontal collusive consequences of vertical restraints. It concludes that networks of vertical restraints blur the differences between vertical and horizontal agreements; therefore, both options of attack are available for enforcers in the EU and the US context. If the analysed vertical restraints are adopted in parallel by agreement, they should be deemed illegal as long as they restrict competition producing collusive consequences. In the absence of explicit coordination to adopt the practice, I suggest first looking for a stretched concept of horizontal agreement or a broadly interpreted concept of concerted practice, including unilateral ‘communication’ that intentionally reduces uncertainty. Even when the analysed practices are adopted individually and not by all firms, they can represent a commitment to focal points, observable by market players, thus amounting to communication of intent. If that is not possible, I propose that an analysis of market power, incentives, coercion and induction should guide the finding of an illegal vertical agreement and ground the analysis of the consequences. The agreement/concerted practice path is an appropriate, feasible and coherent way to deal with vertical restraints facilitating horizontal tacit coordination, but that does not exclude alternative effective enforcement mechanisms.

Coordination mechanism in real-time scheduling of Virtual Cellular Manufacturing Systems

In recent years, Virtual Cellular Manufacturing Systems, which combine virtual cells to construct new manufacturing systems in response to changing market dynamics, have attracted considerable attention. Especially, the real-time scheduling of Virtual Cellular Manufacturing Systems has been of significant importance. In this article, a hybrid control architecture based on multi-agent technology is introduced to support the coordination mechanism to schedule tasks and resources in real-time. Using the revised resource element approach with the pheromone concept, the real-time scheduling problem is divided into two sub-problems, that is, task ranking and resource load-balancing, which can be solved by explicit and implicit coordination mechanisms, respectively. Finally, the proposed coordination mechanism is proven in illustrative examples to perform more efficiently with reduced processing and holding costs.

Onboard centralized frame tree database for intelligent space operations of the Mars Science Laboratory Rover.

Planetary surface science operations performed by robotic space systems frequently require pointing cameras at various objects and moving a robotic arm end effector tool toward specific targets. Earlier NASA Mars Exploration Rovers did not have the ability to compute actual coordinates for given object coordinate frame names and had to be provided with explicit coordinates. Since it sometimes takes hours to more than a day to get final approval of certain calculated coordinates for command uplink via the Earth-based mission operations procedures, a highly desired enhancement for future rovers was to have the onboard automated capability to compute the coordinates for a given frame name. The Mars Science Laboratory (MSL) rover mission is the first to have a centralized coordinate transform database to maintain the knowledge of spatial relations. This onboard intelligence significantly simplifies communication and control between Earth-based human mission operators and the robotic rover on Mars by supporting higher level abstraction of commands using object and target names instead of coordinates. More specifically, the spatial relations of many object frames are represented hierarchically in a tree data structure, called the frame tree. Individual frame transforms are populated by their respective modules that have specific knowledge of the frames. Through this onboard centralized frame tree database, client modules can query transforms between any two frames and support spacecraft commands that use any frames maintained in the frame tree. Various operational examples in the MSL mission that have greatly benefitted from this onboard centralized frame tree database are presented.

Collision Avoidance for Multi-UAV Based on Geometric Optimization Model in 3D Airspace

This paper presents a collision avoidance (CA) algorithm for cooperative unmanned aerial vehicles (UAVs) sharing three-dimensional airspace. The method based on geometric optimization model aims to provide feasible optimal trajectory for the selected UAV, with a local optimization scope at operational level. It generates optimal flight trajectory by the objective function (the integration equation of distance, time and track adjustment costs) in response to a set of restrictions (performance, state and distance constraints) reducing the solution space. The CA maneuver has been validated with various simulations, owning such advantages as optimization spending a minimal cost, robustness considering the global traffic situation, scalability possessing explicit coordinates of waypoints and efficiency in implementing different tests of tuning parameters.

Linking electrostatic effects and protein motions in enzymatic catalysis. A theoretical analysis of catechol o-methyltransferase.

The role of protein motions in enzymatic catalysis is the subject of a hot scientific debate. We here propose the use of an explicit solvent coordinate to analyze the impact of environmental motions during the reaction process. The example analyzed here is the reaction catalyzed by catechol O-methyltransferase, a methyl transfer reaction from S-adenosylmethionine (SAM) to the nucleophilic oxygen atom of catecholate. This reaction proceeds from a charged reactant to a neutral product, and then a large electrostatic coupling with the environment could be expected. By means of a two-dimensional free energy surface, we show that a large fraction of the environmental motions needed to attain the transition state happens during the first stages of the reaction because most of the environmental motions are slower than changes in the substrate. The incorporation of the solvent coordinate in the definition of the transition state improves the transmission coefficient and the committor histogram in solution, while the changes are much less significant in the enzyme. The equilibrium solvation approach seems then to work better in the enzyme than in aqueous solution because the enzyme provides a preorganized environment where the reaction takes place.

Efficient broadcasting in slow fading wireless ad-hoc networks

Broadcasting in wireless ad-hoc networks is the dissemination of messages from a source node to all nodes in the network. Since the nodes may have many common neighbors which can receive the same message from multiple forwarders, many schemes have been proposed to achieve high throughput without much redundancy. The majority of the schemes, however, assume either perfect link reliability or a static unreliability regime. In this paper, we consider the case where broadcasting is performed under slow fading, and thus the link qualities can vary over the course of broadcast periods. In this case, a static forwarding scheme based on a fixed probabilistic model of the link qualities cannot track the instantaneous channel conditions, and is prone to blind re-transmissions. Instead, the nodes have to coordinate in real-time so that high coverage is achieved by involving only a subset of nodes experiencing good channel states. To avoid the need for an explicit costly coordination, we model the broadcast problem as a game in which each node is equipped with a regret-based learning strategy. By repeatedly playing this game, the nodes can learn to reach a consensus (equilibrium) in their forwarding strategies for each global channel state. Also, the nodes proactively adapt their strategies so that their collective forwarding behavior actively tracks the broadcast game׳s equilibrium as it varies with changes in channel states due to slow fading. Simulation results reveal that our solution excels in terms of both the number of transmissions and load distribution, while also maintaining near perfect throughput, especially in dense crowded environments.

Evolutionary computational synthesis of self-organizing systems

AbstractA computational approach for the design of self-organizing systems is proposed that employs a genetic algorithm to efficiently explore the vast space of possible configurations of a given system description. To generate the description of the system, a two-field based model is proposed in which agents are assigned parameterized responses to two “fields,” a task field encompassing environmental features and task objects, and a social field arising from agent interactions. The aggregate effect of these two fields, sensed by agents individually, governs the behavior of each agent, while the system-level behavior emerges from the actions of and interactions among the agents. Task requirements together with performance preferences are used to compose system fitness functions for evolving functional and efficient self-organizing mechanisms. Case studies on the evolutionary synthesis of self-organizing systems are presented and discussed. These case studies focus on achieving system-level behavior with minimal explicit coordination among agents. Agents were able to collectively display flocking, exploration, and foraging through self-organization. The proposed two-field model was able to capture important features of self-organizing systems, and the genetic algorithm was able to generate self-organizing mechanisms by which agents could form task-based structures to fulfill functional requirements.

Ab initio MP2 and density functional theory computational study of AcAlaNH2 peptide hydration: a bottom-up approach.

AcAlaNH2 ⋅ n H2O (n=1-13) complexes have been proposed as models to account for water solvent effects on the molecular properties of N-acetyl-L-alanine amide. Ab initio computations are planned to evaluate peptide-water interactions and to provide a means for approximating relative effects of the short-range many-body interactions arising in real solution without introducing any external parameters intended to quantify empirical or semiempirical potential-energy functions. The present bottom-up approach reveals the formation of compact ring clusters of water molecules strongly bonded to peptidic polar groups throughout hydrogen bonds. The explicit coordination of water molecules around the peptide renders the fully extended (FE) and polyproline II (PPII) conformers more stable with respect to the 310 helix or γ turn. The alternance of donor and acceptor groups on both sides of the FE and PPII conformers allows for synergy and extensive H-bonding.

Gestão de recursos humanos em pequenas e médias empresas

A especialização das funções de gestão teve e tem efeito a possibilidade de aprofundamento de cada uma das áreas de gestão como uma área de conhecimentos específicos, embora, em contrapartida, possa ter feito perder alguma validade pragmática aos corpos de conhecimentos específicos assim desenvolvidos. A análise da literatura e da prática da gestão de recursos humanos sugere a sua inadequação no caso das PME. O artigo explora esta hipótese através da análise de um estudo de caso em que são analisadas as práticas de gestão de recursos humanos que têm lugar uma empresa em que não existe uma função de recursos humanos diferenciada. A análise do caso sugere que existem vários intervenientes na gestão de recursos humanos que agem de formas não explicitamente coordenadas, as quais se foram desenvolvendo ao longo do tempo. Em atuação obtém, no entanto, efeitos em termos de gestão de recursos humanos que correspondem a dois critérios centrais da estrutura de gestão da empresa: a manutenção de uma estrutura de poder centralizada e autocrática e a rapidez de resposta adequada ao mercado em que opera. Esta forma de atuação é instável dadas as alterações no contexto da empresa, que implicaram, entre outras coisas, o início de um processo de certificação de qualidade. Não parece, contudo, possível pensar na sua modificação à luz dos quadros tradicionais da gestão de recursos humanos sem considerar modificações mais profundas de todo o processo organizativo da empresa, o que sugere a necessidade de aprofundar esta questão da validade pragmática do corpo de conhecimentos especializado da gestão de recursos humanos.DOI: http://dx.doi.org/10.17575/rpsicol.v13i1/2.568

Distributed and cooperative task processing: Cournot oligopolies on a graph.

This paper introduces a novel framework for the design of distributed agents that must complete externally generated tasks but also can volunteer to process tasks encountered by other agents. To reduce the computational and communication burden of coordination between agents to perfectly balance load around the network, the agents adjust their volunteering propensity asynchronously within a fictitious trading economy. This economy provides incentives for nontrivial levels of volunteering for remote tasks, and thus load is shared. Moreover, the combined effects of diminishing marginal returns and network topology lead to competitive equilibria that have task reallocations that are qualitatively similar to what is expected in a load-balancing system with explicit coordination between nodes. In the paper, topological and algorithmic conditions are given that ensure the existence and uniqueness of a competitive equilibrium. Additionally, a decentralized distributed gradient-ascent algorithm is given that is guaranteed to converge to this equilibrium while not causing any node to over-volunteer beyond its maximum task-processing rate. The framework is applied to an autonomous-air-vehicle example, and connections are drawn to classic studies of the evolution of cooperation in nature.

Autonomous Schemes for Inter-cell Interference Coordination in the Downlink of LTE Systems

Inter-cell interference (ICI) is one of the key challenges that limit the performance of Long Term Evolution and Long Term Evolution Advanced cellular systems. One approach to deal with ICI is through interference avoidance. Unlike static avoidance techniques where a-priori frequency planning and/or explicit inter-cell coordination is used, dynamic avoidance techniques rely on adapting its frequency planning and allocation based on the current state of the network. However, this improvement in performance comes with the cost of an increased complexity due to the coordination and alignments needed among the base stations (eNB) to manage and allocate channels among the users. Accordingly, autonomous ICI coordination techniques are receiving much interest among the various interference avoidance techniques. In this paper, we propose an autonomous self-adaptive scheme (SA, for short) for radio resource management and interference coordination. We then extend the proposed scheme to become self-adaptive power-aware (SAPA) in order to optimize and reduce the transmission power of the eNBs. A key feature in the proposed schemes is that all computations are independent of the number of users and cells in the network. This allows the proposed schemes to adapt to networks of any size and with an arbitrary number of users. Extensive simulation confirms that the proposed SA scheme ensures efficient frequency reuse patterns that lead to significant performance improvements in the throughput of the edge users without affecting other users. Moreover, the SAPA scheme achieves significant improvement in the power efficiency, while maintaining the throughput enhancements achieved by the SA scheme for both center and edge users.

Assessing neurosurgical non-technical skills: an exploratory study of a new behavioural marker system.

The management of non-technical skills is a major factor affecting teamwork quality and patient safety. This article presents a behavioural marker system for assessing neurosurgical non-technical skills (BMS-NNTS). We tested the BMS during deep brain stimulation surgery. We developed the BMS in three stages. First, we drew up a provisional assessment tool based on the literature and observation tools developed for other surgical specialties. We then analysed videos made in an operating room (OR) during deep brain stimulation operations in order to ensure there were no significant omissions from the skills list. Finally, we used five videos of operations to identify the behavioural markers of non-technical skills in verbal communications. Analyses of more than six hours of observations revealed 3515 behaviours from which we determined the neurosurgeon's non-technical skills behaviour pattern. The neurosurgeon frequently engaged in explicit coordination, situation awareness and leadership behaviours. In addition, the neurosurgeon's behaviours differed according to the stage of the operation and the OR staff members with whom she was communicating. Our behavioural marker system provides a structured approach to assessing non-technical skills in the field of neurosurgery. It can also be transferred to other surgical specialties and used in surgeon training curricula.

Pan-information Location Map

Abstract. A huge amount of information, including geographic, environmental, socio-economic, personal and social network information, has been generated from diverse sources. Most of this information exists separately and is disorderly even if some of it is about the same person, feature, phenomenon or event. Users generally need to collect related information from different sources and then utilize them in applications. An automatic mechanism, therefore, for establishing a connection between potentially-related information will profoundly expand the usefulness of this huge body of information. A connection tie is semantic location describing semantically concepts and attributes of locations as well as relationships between locations, since 80% of information contains some kind of geographic reference but not all of geographic reference has explicit geographic coordinates. Semantic location is an orthogonal form of location representation which can be represented as domain ontology or UML format. Semantic location associates various kinds of information about a same object to provide timely information services according to users’ demands, habits, preferences and applications. Based on this idea, a Pan-Information Location Map (PILM) is proposed as a new-style 4D map to associates semantic location-based information dynamically to organize and consolidate the locality and characteristics of corresponding features and events, and delivers on-demand information with a User-Adaptive Smart Display (UASD).

Study on Cloud Computing Clusters Based on Coordination Method

This paper makes the case that virtualization offers new opportunities to alleviate throughput collapse in data center Ethernet. We present the design, implementation, and evaluation of a prototype system, called XCo, which explicitly coordinates network transmissions from virtual machines across a cluster's Ethernet infrastructure. We show that explicit coordination can be implemented transparently without modifying any applications, standard protocols, network switches, or VMs.

Co-ACT—a framework for observing coordination behaviour in acute care teams

BackgroundAcute care teams (ACTs) represent action teams, that is, teams in which members with specialised roles must coordinate their actions during intense situations, often under high time pressure and with...

An approach to family-centered coordinated co-management for individuals with conditions identified through newborn screening

The care of individuals with rare heritable conditions, such as those detectable through newborn screening, is an important target for quality improvement. Not only is there great opportunity to improve long-term outcomes, but there are lessons that can be generalized to the care of all children with special health-care needs. To identify an approach to quality improvement for individuals with conditions identified through newborn screening, the National Coordinating Center for the Regional Genetic and Newborn Screening Service Collaboratives convened an expert workgroup to develop strategies based on a family-centered, community-based system of care. These recommendations centered on involving families, the primary care medical home, and specialty care providers as equal partners. Key activities to improve care include explicit care coordination, identification of the location of management, and planned co-management. To implement this model of care, the Regional Collaboratives will develop a clearinghouse of tools, engage in activities to evaluate the effectiveness of interventions to improve co-management, and identify strategies to align incentives for health-care providers and families to work together.