Coordination Problems Research Articles

Effect of Balance Exercises on Balance and Walking a Patient with Ataxia Telangiectasia

Ataxia Telangiectasia is a rare autosomal recessive disease characterized by progressive neurological dysfunction, immunodeficiency, telangiectasia, chromosomal problems, and sensitivity to radiation, infection, and susceptibility to cancer. A 5-year-old girl with Ataxia Telangiectasia applied to our rehabilitation center due to balance and coordination problems. Step length, double step length, step width and cadence were calculated in the patient and the distance parameters and the time of the walk were examined. The balance of the patient was also evaluated using the pediatric balance scale. It can be said that balance exercises performed in patients with AT provide increases in the patient's balance, coordination and normalize the gait pattern by reducing ataxia.

Multiperiod DER Coordination Using ADMM-Based Three-Block Distributed AC Optimal Power Flow Considering Inverter Volt-Var Control

The uptake of behind-the-meter distributed energy resources (DER) raises the likelihood of voltage problems in low-voltage distribution networks. Network operators increasingly require solar inverters to provide reactive power support using Volt-Var control (VVC) to reduce voltage stress. However, VVC can cause instability in real-time control because of its instantaneous response to voltage deviations, which has been previously addressed using delayed control methods. Coincidentally, optimization-based multiperiod DER coordination faces a similar problem, where numerical oscillations can prevent the convergence of a distributed algorithm. This paper aims to fill this gap by proposing a distributed three-block algorithm, based on the alternating direction method of multipliers (ADMM), for solving the DER coordination problem using AC optimal power flow (OPF) with VVC constraints. This approach decomposes the network at the prosumer level, resulting in an aggregator, a prosumer, and a VVC block. A key feature of the proposed algorithm is the introduction of carefully tuned delays in the VVC block update to circumvent unstable numerical behavior. This novel approach is numerically demonstrated to solve the distributed OPF problem to feasible solutions with (i) objective function values within less than 2.5% compared to those from centralized computations for tractable cases, (ii) robustness against changes in load/generation profiles and steepness of VVC curves, and (iii) an algorithmic performance that scales linearly with an increase in network size.

A Market Framework for a 100% Renewable Energy Penetration Spot Market

The global installed capacity of renewable energy sources (RESs) is increasing rapidly. The 100% RESs power supply is being pursued. When renewable energy penetration tends to be 100%, the source-load coordination problem becomes extreme. The problems of market failure caused by the near-zero marginal cost of RESs and the scarcity pricing of flexible resources (FRs) participating in the rapid energy deviation balance need to be solved. Accordingly, a spot market framework including the day-ahead renewable energy temporal capacity market and the real-time energy sharing market is proposed in this paper. The RESs and FRs are decoupled to ensure that the homogenous commodities compete together. In the day-ahead stage, to obtain the locational marginal price with the guiding role of resource allocation, the fixed cost of the RESs is apportioned to obtain the spatial-temporal capacity price. In the real-time stage, a price-driven distributed energy sharing mechanism is proposed. It is proven that the sharing mechanism can achieve optimum social welfare and satisfy incentive compatibility. The simulation verifies that the new framework can solve market failure. The real value of FRs is discovered when a price consensus is reached.

From partners to populations: A hierarchical Bayesian account of coordination and convention.

Languages are powerful solutions to coordination problems: They provide stable, shared expectations about how the words we say correspond to the beliefs and intentions in our heads. Yet, language use in a variable and nonstationary social environment requires linguistic representations to be flexible: Old words acquire new ad hoc or partner-specific meanings on the fly. In this article, we introduce continual hierarchical adaptation through inference (CHAI), a hierarchical Bayesian theory of coordination and convention formation that aims to reconcile the long-standing tension between these two basic observations. We argue that the central computational problem of communication is not simply transmission, as in classical formulations, but continual learning and adaptation over multiple timescales. Partner-specific common ground quickly emerges from social inferences within dyadic interactions, while community-wide social conventions are stable priors that have been abstracted away from interactions with multiple partners. We present new empirical data alongside simulations showing how our model provides a computational foundation for several phenomena that have posed a challenge for previous accounts: (a) the convergence to more efficient referring expressions across repeated interaction with the same partner, (b) the gradual transfer of partner-specific common ground to strangers, and (c) the influence of communicative context on which conventions eventually form. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

A multiple-drone arc routing and mothership coordination problem

This paper considers the optimisation problems that arise in coordinating a tandem between a mothership vehicle and a fleet of drones. Each drone can be launched from the mothership to perform a task. After completing their tasks, the drones return to the mothership to recharge their batteries and be ready for a new task. Tasks consist of (partially) visiting graphs of a given length to provide some services or to carry out a surveillance/inspection activity. The goal is to minimise the overall time of travelling carried out by the mothership (makespan) while satisfying some requirements in terms of fractions of visits to the target graphs. In all cases, we develop exact formulations resorting to mixed-integer second-order cone programmes that are compared on a testbed of instances to assess their performance. We also develop a matheuristic algorithm that provides reasonable solutions. Computational experiments show the usefulness of our methodology in different scenarios.

Pricing and Coordination for the Leasing and Recycling of Construction Machinery in a Supply Chain Based on Industrial Internet Platform

Leasing and recycling are important methods for developing the low-carbon sustainability of the construction machinery industry. However, there are some dilemmas caused by the extreme limitations of product service life. There has been little research on construction machinery leasing thus far and a lack of description of its unique characteristics in previous models. Focusing on the problem of pricing and coordination, a two-stage model of a leasing closed-loop supply chain based on the practical application of an Industrial Internet platform was proposed. Under centralized and decentralized decision-making scenarios, the prices of leasing and selling, maintenance effort, and recovery rate were calculated, respectively. By using the Shapley value method to optimize the selling price, and the two-part pricing contract to calculate the compensation fee, global profits can be reasonably distributed, while the supply chain can be improved. The effects of different contracts on the improvement of supply chain profit were investigated. Additionally, the correlation among parameters was explored via sensitivity analysis and numerical simulation. The findings show that the maintenance and recycling of construction machinery can be improved by using an Industrial Internet platform while achieving supply chain coordination via contracts. The enhancement of maintenance effort can decrease remanufacturing costs, which are positively correlated with the selling price and leasing price of products, further promoting the recovery rate of used products. The findings of this paper show that manufacturers can take advantage of the Industrial Internet platform to improve recycling efficiency as well as to decrease product prices and remanufacturing costs by promoting remanufacturing technologies. On the other hand, leasers need to enhance the maintenance of construction machinery. Strengthening cooperation via contracts can jointly promote leasing and recycling in the construction machinery industry and help achieve low-carbon sustainable development.

Distributed Coordination of Space–Ground Multiresources for Remote Sensing Missions

As data relay satellites (DRSs) play an increasingly important supporting role in remote sensing missions, efficient coordination across space–ground multiresources becomes a significant problem. Owing to the implementation problem of the centralized coordinate methods, this paper studies a distributed coordinate resource scheduling method which is realizable in the current space network structure. To be specific, we first formulate the multiple resource coordination problem into an MILP problem based on a modified time-expanded graph. Then, the problem is transferred and decomposed into subproblems for remote sensing satellite (RSS) systems and DRS systems to solve distributedly. Afterwards, we propose a distributed iterative scheme for the RSS systems and DRS systems based on alternating direction method of multipliers (ADMM), in which only the schedule information of the inter-satellite links are required to exchange between RSS systems and DRS systems. Simulation results are provided to validate the effectiveness of our distributed coordinated resource scheduling algorithm.

Cheap Exclusion in Markets with Multiple Complements

We extend the theory of exclusive dealing in first-mover environments to settings where the incumbent seller’s product is used with multiple complements in a distribution chain and the incumbent can sign exclusive dealing contracts with more than one of them. The model is motivated by the market for biosimilar pharmaceuticals, where incumbent sellers that face a threat of entry can sign exclusionary contracts with both providers and insurance carriers prior to entry. We show that when the incumbent’s complementors are vertically related, it can be profitable for the incumbent to sign exclusive contracts with indirect buyers, who operate downstream from the direct buyers of the product. Under linear pricing, such exclusion is profitable if the pass-through rate is sufficiently low, and under nonlinear pricing and symmetric Nash bargaining, it is profitable for all pass-through rates. Complementors face a more severe coordination problem than independent buyers that can make anticompetitive exclusion more likely and especially cheap.

Intelligent Planning for Large-Scale Multi-Robot Coordination

Robots will play a crucial role in the future and need to work as a team in increasingly more complex applications. Advances in robotics have laid the hardware foundations for building large-scale multi-robot systems. But how to coordinate robots intelligently is a difficult problem. We believe that graph-search-based planning can systematically exploit the combinatorial structure of multi-robot coordination problems and efficiently generate solutions with rigorous guarantees on correctness, completeness, and solution quality. We started with one problem that is central to many multi-robot applications. Multi-Agent Path Finding (MAPF) is an NP-hard problem of planning collision-free paths for a team of agents while minimizing their travel times. We addressed the MAPF problem from both (1) a theoretical perspective by developing efficient algorithms to solve large MAPF instances with completeness and optimality guarantees via a variety of AI and optimization technologies, such as constraint reasoning, heuristic search, stochastic local search, and machine learning, and (2) an applicational perspective by developing algorithmic techniques for integrating MAPF with task planning and execution for various multi-robot systems, such as mobile robot coordination, traffic management, drone swarm control, multi-arm assembly, and character control in video games. This paper is part of the AAAI-23 New Faculty Highlights.

Intersection Coordination with Priority-Based Search for Autonomous Vehicles

The development of connected and autonomous vehicles opens an opportunity to manage intersections without signals. One promising approach is to use a central autonomous intersection manager to optimize the movement of the vehicles in the intersection. Existing work uses Mixed Integer Linear Programming (MILP) to find optimal solutions for this problem but is time-consuming and cannot be applied in real-time. On the other hand, the coordination of the vehicles is essentially a Multi-Agent Path Finding (MAPF) problem, for which dozens of efficient algorithms have been proposed in recent years. Inspired by these MAPF algorithms, we propose a three-level algorithm called PSL to solve the intersection coordination problem. Theoretically, PSL is complete and polynomial-time in the number of vehicles. Empirically, PSL runs significantly faster with only a slight compromise in the solution quality than the optimal MILP method. It also generates significantly better solutions with a slightly larger runtime than the traditional First-Come-First-Served strategy.

Counteracting sociocultural barriers in global software engineering using group activities

AbstractIn modern times, internationally organized teams face a number of coordination problems owing to their different physical operating locations. These challenges usually come in temporal, cultural, and linguistic forms. To resolve some of these issues, we need more coordination, teamwork, and shared understanding in the requirements engineering phase. Many approaches have been introduced to overcome these challenges associated with global software engineering (GSE). The objective of this research study is to introduce amateurs to GSE and improve their understanding of its associated challenges through an activity‐based learning approach. Our method is primarily targeted toward students who already have theoretical knowledge on the topic but require first‐hand experience with GSE. With the aforementioned motivation in mind, we propose, designe, and empirically evaluate two different activities that can help enhance awareness of GSE challenges. For each activity, we simulate an environment wherein participants are made to go through various constructed coordination challenges related to communication, time management, team mistrust, linguistic barriers, cultural barriers, and distribution of tasks. The effectiveness of our proposed activities, captured by the extent to which participants were able to deal with GSE challenges, was judged through various techniques including (i) observation, (ii) post activities survey questionnaire, and (iii) brainstorming and discussion. We show that the proposed activities were effective in helping students learn and further their understanding of GSE concepts. In particular, discussion sessions and survey questionnaire results reflect their ability to identify critical GSE challenges (specifically related to teams) in a simulated scenario.

Maximizing the Benefits of an On-Demand Workforce: Fill Rate-Based Allocation and Coordination Mechanisms

Problem definition: With the rapid growth of the gig economy, on-demand staffing platforms have emerged to help companies manage their temporary workforce. This emerging business-to-business context motivates us to study a new form of supply chain coordination problem. We consider a staffing platform managing an on-demand workforce to serve multiple firms facing stochastic labor demand. Before demand realization, each individual firm can hire permanent employees, whereas the platform determines a compensation rate for potential on-demand workers. After knowing the realized demand, firms in need can request on-demand workers from the platform, and then, the platform operator allocates the available on-demand workforce among the firms. We explore how to maximize and distribute the benefits of an on-demand workforce through coordinating self-interested parties in the staffing system. Methodology/results: We combine game theory and online optimization techniques to address the challenges in incentivizing and coordinating the online workforce. We propose a novel and easily implementable fill rate-based allocation and coordination mechanism that enables the on-demand workforce to be shared optimally when individual firms and the platform operator make decisions in their own interest. We also show that the proposed mechanism can be adapted to the cases when contract terms need to be identical to all firms and when actual demand is unverifiable. Managerial implications: The proposed contract mechanism is in line with the performance-based contracting commonly used in on-demand staffing services. Our results suggest that under an appropriately designed performance-based mechanism, individual firms and the platform operator can share the maximum benefits of on-demand staffing. Funding: This work was supported by the National Natural Science Foundation of China [Grant 71871097] and the Fundamental Research Funds for the Central Universities, China. Supplemental Material: The online appendix is available at https://doi.org/10.1287/msom.2021.0327 .

Exploration of the barriers and enablers of benzodiazepines deprescribing in prisons: A qualitative study among health and social care professionals.

The prison environment is a place of high consumption of benzodiazepines (BZDs) due to the anxiety and sleep disturbances, mental disorders, detoxification and trafficking. The study aims to explore experiences of health and social care professionals on the use of BZDs in prisons, as well as the barriers and enablers to their deprescribing. Semistructured individual interviews with professionals working in a prison setting were performed between March and April 2022, based on an interview guide. They were recorded and transcribed using the NVivo software. A qualitative analysis using an inductive approach based on a thematic analysis was performed. Sixteen health professionals were interviewed, including psychiatrists, general practitioners, nurses, pharmacists, psychologists, musicologists and pharmacy technicians. The identified barriers to deprescribing BZDs were problems of coordination between prescribers, lack of time and alternatives. Concerning the enablers, therapeutic education groups, staff's awareness of the irrelevance of some medication and multi-professional advice were identified. This study highlights the similarities in deprescribing difficulties between prison and other settings. Some of the levers identified in our study have shown their effectiveness in different settings. Deprescribing is done most of the time in good conditions but requires an additional delay compared to the outside environment.

Global Manager: A Serious Game to Raise Awareness of the Challenges of Being a Project Manager in Global Software Development

Project managers tend to confront multiple challenges in Global Software Development (GSD), including misunderstandings about the project requirements, complex estimations of costs, risks, and efforts, along with increases in task allocation and a lack of coordination. “Soft skills” play a fundamental role in solving these challenges, as they are the human or social abilities that facilitate the resolution of conflicts and involve dealing with people and managing projects in their most social and creative dimension. However, developing the soft skills that allow project managers to lead in an effective manner is not an easy task, especially in global or distributed environments, where coordination and control problems are commonplace. One suitable mechanism with which to develop these soft skills is that of serious games, which focus on learning by doing and allow users to simulate real scenarios. The authors of this article are aware of the usefulness of this type of teaching method and have, therefore, developed the serious game described herein. This serious game is denominated as Global Manager and is focused on helping both students and novice project managers to become aware of the factors that may affect GSD projects. Global Manager was evaluated by means of a quasi-experiment based on a pretest-posttest design, which was used to assess whether the game can increase the players’ awareness and knowledge of the factors that a project manager should consider in GSD projects. The results obtained after evaluating the game were quite satisfactory, as the game taught the players to differentiate between global and distributed software projects and to experience situations that may and do occur in these settings. Furthermore, Global Manager helped improve players' perceptions of the importance of different influencing factors in GSD.

FIXED MONETARY REGIMES – DEBATES AND ARGUMENTS (Continued)

The article elaborates material published earlier in the journal (Fixed Monetary Regimes – Debates and Arguments // International Trade and Trade Policy, 2023, Vol. 9, N 1 (33), pp. 23–35). The second part of the article examines the features of specific manifestations of types of institutional decisions within the framework of fixed exchange rates. The main problems arising in the coordination of independent national exchange rates are presented. Four institutional and organizational solutions to coordination problems are described in detail, namely: short-term capital movement control, currency management and unilateral dollarization (euroization), as well as a clearing union. The advantages and disadvantages of these solutions are discussed.

Market-based coordination of price-responsive demand using Dantzig-Wolfe decomposition method

The increasing penetration of Distributed Generation (DG) and Demand Responsive (DR) loads in power systems has necessitated the development of novel approaches to address the coordination problem of Price Responsive Devices (PRD). These PRDs are treated as self-interested players aiming to optimize their consumption patterns based on prevailing prices. In this paper, we propose a new algorithm based on the Dantzig-Wolfe (DW) Decomposition method, which tackles the coordination problem of self-interested PRDs in a distributed manner. Leveraging the distributed nature of the DW approach, we model the self-interested algorithms of PRDs as sub-problems within the DW framework. The coordinator, or grid operator, responsible for collecting the energy consumption information (energy bids) of PRDs, solves the master problem of the DW and determines the price signal accordingly.The proposed algorithm exhibits fast convergence as the sub-problems within DW, which could involve a large number of PRDs (potentially millions), can be solved simultaneously. Additionally, based on the DW theory, if the PRDs' subproblems are convex, reaching the optimal point (equivalent to Nash Equilibrium) is guaranteed within a limited number of iterations. To evaluate the proposed model, we conducted a simulation involving 200 participant households, each equipped with two types of loads: Electric Vehicles (EVs) as examples of interruptible loads, and Electric Water Heaters (EWHs) as examples of Thermostatically Controlled Loads (TCLs). The results demonstrate that when the algorithm converges to the optimal point, both the generation cost and user payment (based on the marginal cost of generation) decrease. Furthermore, there is a significant reduction in the Peak to Average Ratio (PAR) of the aggregate load

Learning to cooperate for low-Reynolds-number swimming: a model problem for gait coordination

Biological microswimmers can coordinate their motions to exploit their fluid environment—and each other—to achieve global advantages in their locomotory performance. These cooperative locomotion require delicate adjustments of both individual swimming gaits and spatial arrangements of the swimmers. Here we probe the emergence of such cooperative behaviors among artificial microswimmers endowed with artificial intelligence. We present the first use of a deep reinforcement learning approach to empower the cooperative locomotion of a pair of reconfigurable microswimmers. The AI-advised cooperative policy comprises two stages: an approach stage where the swimmers get in close proximity to fully exploit hydrodynamic interactions, followed a synchronization stage where the swimmers synchronize their locomotory gaits to maximize their overall net propulsion. The synchronized motions allow the swimmer pair to move together coherently with an enhanced locomotion performance unattainable by a single swimmer alone. Our work constitutes a first step toward uncovering intriguing cooperative behaviors of smart artificial microswimmers, demonstrating the vast potential of reinforcement learning towards intelligent autonomous manipulations of multiple microswimmers for their future biomedical and environmental applications.

Leadership, a Soap Opera of Genes-Memes Interaction

The drama of leadership evolved around its definition, what kind is wanted, what processes conduct it, what institutions channel through or around it, what values measure it, and what results test it. Leadership scholarship suggests the hypothesis of a soap opera of genes-memes interaction. The lens of metasynthesis was used on the literature. We used the biopsychosocial approach to include papers from animal and human literatures and from biology, psychology, and social sciences. We included in this review papers that were deemed most relevant. Papers were analyzed using visual methods. Leadership is an old topic with an ever-growing interest. Work on leadership has grown steadily from year to year. Since its emergence in pre-humans, leadership was imitated by humans, and adapted to the development of societies. Leadership is a universal concept in animal and human literature. It was studied by more than twenty (20) academic disciplines. Anyone can become a leader if genes and memes offer him a morphological, physiological, or behavioral trait that increases his propensity to act first in coordination problems. Leading requires touching people's heads and hearts. To achieve this, the leader, like a scientist, craftsman, and artist, uses the fundamental human values that he packs into a project for the future. Leadership is an ability. This study offered an opportunity to visualize leadership. Experiments on leadership development will quantify the impact of mirroring.

A method for the geometric calibration of ultrasound transducer arrays with arbitrary geometries

Geometric calibration of ultrasound transducer arrays is critical to optimizing the performance of photoacoustic computed tomography (PACT) systems. We present a geometric calibration method that is applicable to a wide range of PACT systems. We obtain the speed of sound and point source locations using surrogate methods, which results in a linear problem in the transducer coordinates. We characterize the estimation error, which informs our choice of the point source arrangement. We demonstrate our method in a three-dimensional PACT system and show that our method improves the contrast-to-noise ratio, the size, and the spread of point source reconstructions by 80±19%, 19±3%, and 7±1%, respectively. We reconstruct the images of a healthy human breast before and after calibration and find that the calibrated image reveals vasculatures that were previously invisible. Our work introduces a method for geometric calibration in PACT and paves the way for improving PACT image quality.

Care coordination in homecare and its relationship with quality of care: A national multicenter cross-sectional study

IntroductionAs health care complexity increases, skilled care coordination is becoming increasingly necessary. This is especially true in homecare settings, where services tend to be highly interprofessional. Poor coordination can result in services being provided twice, at the wrong time, unnecessarily or not at all. In addition to risking harm to the client, such confusion leads to unnecessary costs. From the patient's perspective, then, professional coordination should help both to remove barriers limiting quality of care and to minimize costs. To date, though, studies examining the relationship between care coordination and care quality have faced multiple challenges, leading to mixed results. And in homecare contexts, where the clients are highly vulnerable and diverse care interfaces make coordination especially challenging, such studies are rare. ObjectivesTherefore, the aim of this study was to explore the relationship, from the perspectives of clients and of homecare professionals, between coordination and quality of care. For both groups, we hypothesized that better coordination would correlate with higher ratings of quality of care. For the clients, we predicted that higher coordination ratings would lead to lower incidence of unplanned health care use, i.e., emergency department (ED) visits, unscheduled urgent medical visits and hospitalizations. Design and methodsThis study is part of a national multi-center cross-sectional study in the Swiss homecare setting. We recruited 88 homecare agencies and collected data between January and September 2021 through written questionnaires for agencies' managers, employees (n = 3223) and clients (n = 1509). To test our hypotheses, we conducted multilevel analyses. ResultsEmployee-perceived care coordination ratings correlated positively with employee-rated quality of care (OR = 2.78, p < .001); client-perceived care coordination problems correlated inversely with client-reported quality of care (β = −0.55, p < .001).Client-perceived coordination problems also correlated positively with hospitalizations (IRR = 1.20, p < .05) and unscheduled urgent medical visits (IRR = 1.18, p < .05), but not significantly with ED visits. No associations were discernible between employee-perceived coordination quality and either health care service use or client quality-of-care ratings. DiscussionWhile results indicate relationships between coordination and diverse aspects of care quality, various coordination gaps (e.g., poor information flow) also became apparent. The measurement of both care coordination and quality of care remains a challenge. Further research should focus on developing and validating a coordination questionnaire that measures care coordination.