| 51. |
- Dolev, Shlomi, et al.
(författare)
-
Game Authority for Robust and Scalable Distributed Selfish Computer Systems
- 2007
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Ingår i: Proceedings of the twenty-sixth annual ACM symposium on Principles of distributed computing. - 9781595936165 ; , s. 356 - 357
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Konferensbidrag (refereegranskat)abstract
- Game theory analyzes social structures of agents that have freedomof choice within a moral code. The society allows freedom andselfishness within the moral code, which social structures enforce,i.e., legislative, executive, and judicial. Social rules encourage individualprofit from which the entire society gains. Distributed computersystems can improve their scalability and robustness by usingexplicit social structures. We propose using a game authority middlewarefor enforcing the moral code on selfish agents.The power of game theory is in predicting the game outcome forspecific assumptions. The prediction holds as long as the playerscannot tamper with the social structure, or change the rules of thegame, i.e., the prisoner cannot escape from prison in the classicalprisoner dilemma. Therefore, we cannot predict the game outcomewithout suitable assumptions on failures and honest selfishness.
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| 52. |
- Dolev, Shlomi, et al.
(författare)
-
Game authority for robust and scalable distributed selfish-computer systems
- 2010
-
Ingår i: Theoretical Computer Science. - : Elsevier BV. - 0304-3975. ; 411:26-28, s. 2459-2466
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Tidskriftsartikel (refereegranskat)abstract
- Distributed algorithm designers often assume that system processes execute the same predefined software. Alternatively, when they do not assume that, designers turn to noncooperative games and seek an outcome that corresponds to a rough consensus when no coordination is allowed. We argue that both assumptions are inapplicable in many real distributed systems, e.g., the Internet, and propose designing self-stabilizing and Byzantine fault-tolerant distributed game authorities. Once established, the game authority can secure the execution of any complete information game. As a result, we reduce costs that are due to the processes' freedom of choice. Namely, we reduce the price of malice. (C) 2010 Elsevier B.V. All rights reserved.
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| 53. |
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| 54. |
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| 55. |
- Dolev, Shlomi, et al.
(författare)
-
Strategies for repeated games with subsystem takeovers implementable by deterministic and self-stabilising automata
- 2011
-
Ingår i: International Journal of Autonomous and Adaptive Communications Systems. - 1754-8640 .- 1754-8632. ; 4:1, s. 4-38
-
Tidskriftsartikel (refereegranskat)abstract
- Systems of selfish-computers are subject to transient faults due to temporal malfunctions; just as the society is subjected to human mistakes. Game theory uses punishment for deterring improper behaviour. Due to faults, selfish-computers may punish well-behaved ones. This is one of the key motivations for forgiveness that follows any effective and credible punishment. Therefore, unplanned punishments must provably cease in order to avoid infinite cycles of unsynchronised behaviour of 'tit for tat'. We investigate another aspect of these systems. We consider the possibility of subsystem takeover. The takeover may lead to joint deviations coordinated by an arbitrary selfish-computer that controls an unknown group of subordinate computers. We present strategies that deter the coordinator from deviating in infinitely repeated games. We construct deterministic automata that implement these strategies with optimal complexity. Moreover, we prove that all unplanned punishments eventually cease by showing that the automata can recover from transient faults.
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| 56. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
3Dwm: A Platform for Research and Development of Three-Dimensional User Interfaces
- 2003
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Although hugely successful, the near-ubiquitous WIMP paradigm dates back to the 1970s and has many shortcomings that could be addressed by harnessing modern computing technology in the user interface. Most importantly, the ready supply of consumer-level hardware-accelerated 3D graphics has opened the way for 3D user interfaces, i.e. interfaces that make direct use of the third dimension. However, there are many challenges to designing applications with such interfaces. In this paper, we present 3Dwm, an object-oriented software platform for the research and development of 3D user interfaces, and discuss how it addresses these challenges. 3Dwm provides a unified 3D abstraction layer that facilitates interoperability between 3D components, combats the inherent complexity of 3D interface programming, provides a reusable toolkit for application building, supports network-aware 3D visualization applications, and may potentially serve as a standardized software platform for many kinds of 3D graphics development.
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| 57. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
A Taxonomy of 3D Occlusion Management for Visualization
- 2008
-
Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1941-0506 .- 1077-2626. ; 14:5, s. 1095-1109
-
Tidskriftsartikel (refereegranskat)abstract
- While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 50 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. We also discuss the "gaps" in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.
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| 58. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
A Taxonomy of 3D Occlusion Management Techniques
- 2006
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 25 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. Wealso discuss the ``gaps'' in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.
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| 59. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
A Taxonomy of 3D Occlusion Management Techniques
- 2007
-
Ingår i: Proceedings of the IEEE Conference on Virtual Reality 2007.
-
Konferensbidrag (refereegranskat)abstract
- While an important factor in depth perception, the occlusion effect in 3D environments also has a detrimental impact on tasks involving discovery, access, and spatial relation of objects in a 3D visualization. A number of interactive techniques have been developed in recent years to directly or indirectly deal with this problem using a wide range of different approaches. In this paper, we build on previous work on mapping out the problem space of 3D occlusion by defining a taxonomy of the design space of occlusion management techniques in an effort to formalize a common terminology and theoretical framework for this class of interactions. We classify a total of 25 different techniques for occlusion management using our taxonomy and then go on to analyze the results, deriving a set of five orthogonal design patterns for effective reduction of 3D occlusion. We also discuss the gaps in the design space, areas of the taxonomy not yet populated with existing techniques, and use these to suggest future research directions into occlusion management.
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| 60. |
- Elmqvist, Niklas, 1977, et al.
(författare)
-
Animated Visualization of Causal Relations Through Growing 2D Geometry
- 2004
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Ingår i: Information Visualization. ; 3:3, s. 154-172
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Tidskriftsartikel (refereegranskat)abstract
- Causality visualization is an important tool for many scientific domains that involve complex interactions between multiple entities (examples include parallel and distributed systems in computer science). However, traditional visualization techniques such as Hasse diagrams are not well-suited to large system executions, and users often have difficulties answering even basic questions using them, or have to spend inordinate amounts of time to do so. In this paper we present the Growing Squares and Growing Polygons methods, two sibling visualization techniques that were designed to solve this problem by providing efficient 2D causality visualization through the use of color, texture, and animation. Both techniques have abandoned the traditional linear timeline and instead map the time parameter to the size of geometrical primitives representing the processes; in the Growing Squares case, each process is a color-coded square that receives color influences from other process squares as messages reach it; in the Growing Polygons case, each process is instead an $n$-sided polygon consisting of triangular sectors showing color-coded influences from the other processes. We have performed user studies of both techniques, comparing them with Hasse diagrams, and they have been shown to be significantly more efficient than old techniques, both in terms of objective performance as well as the subjective opinion of the test subjects (the Growing Squares technique is, however, only significantly more efficient for small systems).
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