Browsing by Subject "Cooperation"

Now showing 1 - 10 of 10
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    Cooperation in Games
    (2019-05) Damer, Steven
    This dissertation explores several problems related to social behavior, which is a complex and difficult problem. In this dissertation we describe ways to solve problems for agents interacting with opponents, specifically (1) identifying cooperative strategies,(2) acting on fallible predictions, and (3) determining how much to compromise with the opponent. In a multi-agent environment an agent’s interactions with its opponent can significantly affect its performance. However, it is not always possible for the agent to fully model the behavior of the opponent and compute a best response. We present three algorithms for agents to use when interacting with an opponent too complex to be modelled. An agent which wishes to cooperate with its opponent must first identify what strategy constitutes a cooperative action. We address the problem of identifying cooperative strategies in repeated randomly generated games by modelling an agent’s intentions with a real number, its attitude, which is used to produce a modified game; the Nash equilibria of the modified game implement the strategies described by the intentions used to generate the modified game. We demonstrate how these values can be learned, and show how they can be used to achieve cooperation through reciprocation in repeated randomly generated normal form games. Next, an agent which has formed a prediction of opponent behavior which maybe incorrect needs to be able to take advantage of that prediction without adopting a strategy which is overly vulnerable to exploitation. We have developed Restricted Stackelberg Response with Safety (RSRS), an algorithm which can produce a strategy to respond to a prediction while balancing the priorities of performance against the prediction, worst-case performance, and performance against a best-responding opponent. By balancing those concerns appropriately the agent can perform well against an opponent which it cannot reliably predict. Finally we look at how an agent can manipulate an opponent to choose actions which benefit the agent. This problem is often complicated by the difficulty of analyzing the game the agent is playing. To address this issue, we begin by developing a new game, the Gift Exchange game, which is trivial to analyze; the only question is how the opponent will react. We develop a variety of strategies the agent can use when playing the game, and explore how the best strategy is affected by the agent’s discount factor and prior over opponents.
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    Cooperation, Competition, and Killing: Reproductive strategies of chimpanzees (Pan troglodytes)
    (2023-08) Massaro, Anthony
    Group-living commonly involves tensions between conflict and cooperation. Group members need one another to survive, but also compete for access to key resources such as food and mates. To better understand reproductive strategies in group-territorial species with sex-biased dispersal, I used decades of data from Gombe National Park, Tanzania to test hypotheses regarding how and why chimpanzees (Pan troglodytes) cooperate, compete, and fight. First, I found that male chimpanzees exhibit a consistently high degree of participation in boundary patrols (mean=75%) and that the best predictors of participation in patrols were sighting frequency and participation in hunting bouts, indicating a mutualistic payoff structure for male territorial effort. Second, I found that female chimpanzees produced copulation calls more frequently when they were nulliparous, and in the early days of their swelling. Thus, these calls likely function as an anti-infanticide strategy, inducing otherwise uninterested males to mate and maximizing the pool of potential sires. Females also called less frequently in the presence of higher-ranking females, indicating that intrasexual competition plays a role in call production. Third, I found that males killed by other chimpanzees suffered a higher-than-expected rate of genital wounding, but during non-fatal fighting, only in one of four communities (Kasekela) did males experience a higher-than-expected rate of genital wounds. Females in all four study communities experienced a higher-than-expected rate of genital wounds, indicating that genital wounding is an unlikely alternative to lethal aggression. Finally, I found that lethal aggression was more common in Mitumba than Kasekela. As a smaller community, Mitumba has fewer females and thus less overlap between reproductively active females and a greater opportunity to monopolize mating opportunities. Overall, this work emphasizes the importance of within-group reproductive competition.
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    Dynamics of Cross-Sector Collaboration: Minnesota's Urban Partnership Agreement from Start to Finish
    (Intelligent Transportation Systems Institute, Center for Transportation Studies, 2012-02) Bryson, John M.; Crosby, Barbara C.; Stone, Melissa M.; Saunoi-Sandgren, Emily
    The problems faced by today's public managers are often too large to be solved by a single entity, and require collaboration across government, nonprofit, and business sectors. As new technologies and systematic approaches transform the transportation field, cross-sector collaboration has become an increasingly important policy development and implementation approach. Particularly within the transportation field, an assemblage of technologies is often critical to implementing system-wide strategies aimed at, for example, mitigating traffic congestion. In many cases, designers and implementers of effective transportation policies must combine a variety of technologies with deft relationship building and management. Through the development of comparative case studies of the Urban Partnership Agreement (UPA) initiatives, this research study will complete the examination from start to finish of the Minnesota UPA, and provide additional comparative information from other UPA sites to enhance the certainty of conclusions, and to develop sound lessons for practitioners.
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    Eco-evolutionary feedbacks in microbial coexistence
    (2025) Zorrilla Gonzalez, Rodrigo
    Species interactions are a hallmark of all ecosystems. Environmental changes can alter how species interact or even whether they interact at all. This can affect the tipping point between coexistence and competitive exclusion, which can have cascading effects on community composition, and ecosystem function. Microbes interact in surprisingly complex ways; their small size, simple genomes, and fast generation times make them excellent tools for studying such eco-evolutionary processes in real time. I use a microbial model system composed of flocculant and non-flocculant strains of Kluyveromyces lactis to investigate how resource availability influences the maintenance and evolution of their coexistence. First, I reduce population density during flocculation to establish the effects of interaction frequency on community composition. Second, I analyze how changes to resource availability lead to deviations from these expectations. This work contributes to broader ecological principles by describing how species interactions and differential responses to environmental change affect community composition.
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    Effective Social Media Engagement Options for Minnesota’s Diversifying Population
    (Minnesota Department of Transportation, 2018-02) Schneider, Ingrid E.; Quick, Kathryn; Peck, Melissa; Pflughoeft, Ben
    Minnesota Department of Transportation (MnDOT) and Minnesota Local Road Research Board (LRRB) supported the University of Minnesota to investigate social media options for effective public engagement. A three-part approach assessed 1) the state of social media use through a literature review, 2) the status of social media use and interest in its use for transportation in Minnesota compared to national data, and 3) actual and perceived effectiveness of social media in two pairs of case studies in Minnesota. In sum, results reveal social media is effective as a strategic and select part of engagement plans and can likely effectively engage select groups. Survey results revealed 11-21% of respondents participated in planning for transportation programs, policies or projects in the last 12 months, 72% use social media of some sort, and 36% expressed interest in using social media to get information, provide feedback or make suggestions related to transportation. Finally, social media analytics and interviews related to four case studies revealed social media does indeed lead transportation projects to make more connections with stakeholders, but the quality and effectiveness of those connections vary. Four main opportunities include: 1) integrating social media into multi-pronged, dynamic engagement approaches, 2) considering the demographic qualities of the key stakeholders to determine how social media can be most useful, 3) employing best practices for social media engagement, and 4) expanding and/ or developing research and evaluation plans to understand and assess future social media engagement efforts.
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    New Spaces: On Territoriality in an Expansive Era
    (2024) Graefe, Carl
    New Spaces: On Territoriality in an Expansive Era introduces the concept of a territorial supply shock to the study of international relations (IR). The field of IR has long operated under the notion that the amount of space that international actors have to interact with and in is static. This assumption of fixed territorial supply ignores three significant additions to the supply of territory in the world: the Earth’s poles, the deep oceans, and Earth orbit. New Spaces conducts basic research into how the general notion that territorial supply is dynamic, and the three new spaces impact the study of international relations. Using an innovative combination of computer simulation and historical case study, New Spaces uncovers the counterintuitive notion that interstate cooperation rather than competition is the modal political outcome in these new spaces. The findings present in new spaces have potential to significantly impact IR theory in areas of territorial conflict, conceptualizing the state, and international cooperation. Additionally, the insight gained from the addition of the study of the poles, the oceans, and outer space adds significant new data to the archive used to test theories of international relations. Finally, the methodology employed in New Spaces provides two innovations. The first is to offer a demonstration of multimethod research built around a generative approach to social science that has much to offer those handling complex and new questions for IR. The second is a more thorough treatment of the international system as a complex socio-environmental system, knitting together aspects of IR that are often studied separately.
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    Resource hoarding facilitates cheating in the legume-rhizobia symbiosis and bet-hedging in the soil.
    (2010-06) Ratcliff, William C.
    The carbon that rhizobia in root nodules receive from their host powers both reproduction and the synthesis of the storage polyester poly3-hydroxybutyrate (PHB), as well as N2 fixation, which mainly benefits the host. Rhizobia escaping nodules can use stored PHB to survive starvation and reproduce up to 3-fold, but PHB synthesis is energetically expensive and trades-off with N2 fixation. As a result, PHB synthesis is a central mechanism in the evolution of conflict between rhizobia and legumes, and should be included in estimates of rhizobial fitness. Some rhizobia have evolved sophisticated mechanisms to increase PHB accumulation, such as the production of rhizobitoxine, a chemical inhibitor of legume ethylene synthesis. Rhizobitoxine reduces host growth, decreasing rhizobia per nodule for all strains on a plant, but substantially increases PHB accumulation for rhizobitoxine-producing rhizobia. In addition to enhancing reproduction, PHB has a role in bet-hedging: when starved, free-living high-PHB rhizobia divide asymmetrically, forming dormant, high-PHB „persisters‟ that survive long-term starvation and antibiotic treatment, and low-PHB „growers‟ that are sensitive to these stresses. Sinorhizobium meliloti integrates bet hedging and phenotypic plasticity, forming fewer high-PHB persister cells when low competitor density predicts shorter-term starvation. Declining populations may select for delayed reproduction when there is a trade-off between reproduction and longevity, as there is with starving S. meliloti.
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    Team Building at the State Fair Celebration
    (1998) Mitchell, James; Rugg, Bradley; Charland, Michael
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    Understanding U.S. civil-military cooperation in the U.S. provincial reconstruction teams (PRTs) in Afghanistan
    (2012-09) Fritsch, Jocelyn
    The purpose of this study was to determine how the provincial reconstruction team (PRT) organizational structure promotes cooperation within U.S. PRTs in Regional Command East (RC/E) in Afghanistan between 2009 and 2010. A case study approach, incorporating qualitative methods, was used. Twenty candidates were selected using purposeful sampling. These candidates participated in semi-structured, individual interviews. Interviewees included civilians and military personnel working with the PRTs in Afghanistan. Definitions of cooperation, cooperative behaviors, and non-cooperative behaviors were generated. These findings, in combination with social network analysis, were utilized to further identify and explain specific conditions and relationships required for effective civil-military cooperation in the PRTs. Using social networking sociographs, organizational structures that best promoted or not promoted civilian-military cooperation were mapped and compared. The study's results may serve as a useful guide for U.S. civilian and military leaders when considering the establishment of PRTs in other post-conflict countries.
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    The Urban Partnership Agreement: A Comparative Study of Technology and Collaboration in Transportation Policy Implementation
    (Center for Transportation Studies, 2011-04) Bryson, John M.; Crosby, Barbara C.; Stone, Melissa M.; Saunoi-Sandgren, Emily; Imboden, Anders S.
    The problems faced by today's public managers are often too large to be solved by a single entity and require collaboration across government, nonprofit, and business sectors. As new technologies and systematic approaches transform the transportation field, cross-sector collaboration has become an increasingly important policy development and implementation approach. Particularly within the transportation field, an assemblage of technologies is often critical to implementing system-wide strategies aimed at, for example, mitigating traffic congestion. In many cases, designers and implementers of effective transportation policies must combine a variety of technologies with deft relationship building and management. Through the development of comparative case studies of three of the Urban Partnership Agreement initiatives, this research study will examine how technology and collaborative processes may be combined to achieve important transportation goals and create public value more generally.