Learning task performance in market-based task allocation

© 2012 Springer-Verlag. The original publication is available at www.springerlink.com.Presented at the 12th International Conference on Intelligent Autonomous Systems (IAS-12) held June 26-29, 2012, Jeju Island, Korea.DOI: 10.1007/978-3-642-33932-5_57Auction based algorithms offer effective methods for de-centralized task assignment in multi-agent teams. Typically there is an implicit assumption that agents can be trusted to effectively perform assigned tasks. However, reliable performance of team members may not always be a valid assumption. An approach to learning team member performance is presented, which enables more efficient task assignment. A policy gradient reinforcement learning algorithm is used to learn a cost factor that can be applied individually to auction bids. Experimental results demonstrate that agents that model team member performance using this approach can more efficiently distribute tasks in multi-agent auctions

A new model of renal microvascular endothelial injury

A new model of renal microvascular endothelial injury. Although the importance of injury with consequent activation of endothelium is well-recognized in diseases affecting the glomerular endothelial cell (GEN), research on GEN injury in vivo has been hampered by the lack of adequate animal models. Here we report the establishment and characterization of a new GEN injury model in rats. This model was induced by selective renal artery perfusion with anti-GEN IgG and resulted in the severe acute renal failure with marked platelet deposition and development of a thrombotic microangiopathy involving glomeruli. Peritubular capillary endothelial cells were also damaged that was associated with severe tubular necrosis. Although the glomerular changes were severe, half of the glomeruli recovered by day 10, while interstitial changes remained throughout our observation time course. Proliferation of GEN was observed during the recovery phase. An increased expression of endothelial nitric oxide synthase in GEN was also observed, and may be an adaptive mechanism to counteract the thrombosis and ischemia. This model should be useful to investigate the pathophysiology of renal microvascular diseases and the mechanisms of GEN injury, activation and recovery in vivo

Modulation of experimental mesangial proliferative nephritis by interferon-γ

Modulation of experimental mesangial proliferative nephritis by interferon-γ. The observation that interferon-γ (IFN-γ) inhibits cell proliferation and collagen synthesis of a variety of cell types in culture has suggested that IFN-γ may be useful in the treatment of fibroproliferative diseases. We administered recombinant IFN-γ subcutaneously (105 U/kg/day for 3 days) to rats, beginning one day after the induction of mesangial proliferative nephritis with anti-Thy 1 antibody. IFN-γ reduced glomerular (primarily mesangial) cell proliferation by 44% at days 2 and 4 compared to vehicle injected control rats with anti-Thy 1 nephritis (that is, proliferating cells that excluded the macrophage marker, ED-1, P < 0.001). Despite the inhibition of mesangial cell proliferation, IFN-γ did not reduce the overall extracellular matrix deposition (by silver stain) or deposition of type IV collagen or laminin (by immunostaining) at 4 or 7 days, and glomerular type IV collagen and laminin mRNA levels were increased (1.4 and 1.7-fold) at 4 days relative to controls. The inability of IFN-γ treatment to reduce mesangial matrix expansion may relate to the fact that IFN-γ treated rats had a twofold increase in glomerular macrophages (that is, ED-1 positive cells, P < 0.001 at 2 and 4 days) with an increase in oxidant producing cells (day 2, P < 0.05) and a 1.6-fold increase in glomerular TGF-β mRNA expression (4 days). This suggests that the effect of IFN-γ to inhibit mesangial cell proliferation in glomerulonephritis may be offset by the ability of IFN-γ to increase glomerular macrophages and TGF-β expression. These data also show that IFN-γ can partly dissociate the mesangial proliferative response from the extracellular matrix expansion in glomerulonephritis

Honneth, Butler and the Ambivalent Effects of Recognition

This paper examines the ambivalent effects of recognition by critically examining Axel Honneth’s theory of recognition. I argue that his underlying perfectionist account and his focus on the psychic effects of recognition cause him to misrepresent or overlook significant connections between recognition and power. These claims are substantiated by (1) drawing from Butler’s theory of gender performativity, power and recognition; and (2) exploring issues arising from the socio-institutional recognition of trans identities. I conclude by suggesting that certain problems with Butler’s own position can corrected by drawing more from the Foucauldian aspects of her work. I claim that this is the most promising way to conceptualise recognition and its complex, ambivalent effects

Incentive based cooperation in multi-agent auctions

© 2011 Association for the Advancement of Artificial IntelligencePresented at AAAI Spring Symposium, March 26–28, 2012 in Palo Alto, California.Market or auction based algorithms offer effective methods for de-centralized task assignment in multi-agent teams. Typically there is an implicit assumption that agents are willing to cooperate and can be trusted to perform assigned tasks. Reciprocal collaboration may not always be a valid assumption. In cases where auctions are used for task allocation, without explicit revenue exchange, incentives are needed to enforce cooperation. An approach to incentive based trust is presented, which enables detection of team members that are not contributing and for dynamic formation of teams

Performance based dynamic team formation in multi-agent auctions

© 2012 Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic electronic or print reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.DOI: 10.1117/12.919551Auction based methods are often used to perform distributed task allocation on multi-agent teams. Many existing approaches to auctions assume fully cooperative team members. On in-situ and dynamically formed teams, reciprocal collaboration may not always be a valid assumption. This paper presents an approach for dynamically selecting auction partners based on observed team member performance and shared reputation. In addition, we present the use of a shared reputation authority mechanism. Finally, experiments are performed in simulation on multiple UAV platforms to highlight situations in which it is better to enforce cooperation in auctions using this approach

Performance based monitoring using statistical control charts on multi-robot teams

© 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.Presented at the 15th International Conference on Information Fusion (FUSION 2012), 9-12 July 2012.On typical multi-robot teams, there is an implicit assumption that robots can be trusted to effectively perform assigned tasks. However, reliable performance of team members may not always be a valid assumption. For instance, a robot’s performance may deteriorate over time or a robot may not estimate tasks correctly. Traditional health monitoring techniques call attention to an operator or assume a binary classification of either success or failure. Robots that can identify poorly performing team members, as performance deteriorates, can adjust the task assignment process dynamically. This paper investigates the use of statistical process control charts from operations research as a tool for monitoring team member performance as part of a multi-robot task assignment framework

Dynamic, cooperative multi-robot pa trolling with a team of UAVs

© 2013. Society of Photo-Optical Instrumentation Engineers. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited. http://dx.doi.org/10.1117/12.2014978DOI: 10.1117/12.2014978The multi-robot patrolling task has practical relevance in surveillance, search and rescue, and security applications. In this task, a team of robots must repeatedly visit areas in the environment, minimizing the time in-between visits to each. A team of robots can perform this task efficiently; however, challenges remain related to team formation and task assignment. This paper presents an approach for monitoring patrolling performance and dynamically adjusting the task assignment function based on observations of teammate performance. Experimental results are presented from realistic simulations of a cooperative patrolling scenario, using a team of UAVs

Performance based task assignment in multi- robot patrolling

© 2013 ACMPermission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission and/or a fee.Presented at Presented at the 28th Annual ACM Symposium on Applied Computing, SAC’13, March 18-22, 2013, Coimbra, Portugal.DOI: 10.1145/2480362.2480378This article applies a performance metric to the multi-robot patrolling task to more efficiently distribute patrol areas among robot team members. The multi-robot patrolling task employs multiple robots to perform frequent visits to known areas in an environment, while minimizing the time between node visits. Conventional strategies for performing this task assume that the robots will perform as expected and do not address situations in which some team members patrol inefficiently. However, reliable performance of team members may not always be a valid assumption. This paper considers an approach for monitoring robot performance in a patrolling task and dynamically reassigning tasks from those team members that perform poorly. Experimental results from simulation and on a team of indoor robots demonstrate that in using this approach, tasks can be dynamically and more efficiently distributed in a multi-robot patrolling application

Making Faith One's Own: Kevin Hector's Defense of Modern Theology

In The Theological Project of Modernism, Kevin Hector of the University of Chicago Divinity School offers a nuanced and timely defense of what he sees as an unjustifiably maligned tradition in modern Christian theology. He focuses on what is commonly labeled the liberal or revisionist tradition, centered in its early stages on figures such as Immanuel Kant, Friedrich Schleiermacher, G. W. F. Hegel, Albrecht Ritschl, Ernst Troeltsch, and, more recently, Paul Tillich. By carefully reconstructing key arguments from these thinkers, Hector shows not only how this trajectory hangs together as a tradition, but also how its animating impulse differs from what many critics have assumed. Hector's central claim is that this tradition is fundamentally concerned with a distinctive problem, namely, how to relate religious faith to a sense of one's life as one's own—or, put differently, how one's faith can be self-expressive. Hector labels this the problem of “mineness,” or the problem of “how persons could identify with their lives or experience them as ‘mine,’ especially given their vulnerability to tragedy, injustice, luck, guilt, and other ‘oppositions’” (viii). Hector argues that for his chosen thinkers in this tradition, faith—more specifically, faith in a God who is able to reconcile such oppositions—plays a crucial role in resolving this problem