Authors: Ji Ruan and Michael Thielscher
School of Computer Science and Engineering, The University of New South Wales, Australia

Abstract: The game description language GDL has been developed as a logic-based formalism for representing the rules of arbitrary games in general game playing. A recent language extension called GDL-II allows to describe nondeterministic games with any number of players who may have incomplete, asymmetric information. In this paper, we show how the well-known Alternating-time Temporal Epistemic Logic (ATEL) can be adapted for strategic and epistemic reasoning about general games described in GDL-II. We provide a semantic characterisation of GDL-II descriptions in terms of ATEL models. We also provide a syntactic translation of GDL-II descriptions into ATEL formulas, and we prove that these two characterisations are equivalent. We show that model checking in this setting is decidable by giving an algorithm, and we demonstrate how our results can be used to verify strategic and epistemic properties of games described in GDL-II.

Accepted at ECAI 2012, the biennial European Conference on Artificial Intelligence.

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2. Conference paper: A Logic for Knowledge Flow in Social Networks Title: A Logic for Knowledge Flow in Social Networks Authors: Ji Ruan...
3. SYNTHESE Journal paper: Action Emulation Title: Action Emulation Authors: Jan van Eijck, Ji Ruan &...

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Authors: Jan van Eijck, Ji Ruan & Tomasz Sadzik

Abstract:
The effects of public announcements, private communications, deceptive messages to groups, and so on, can all be captured by a general mechanism of updating multi-agent models with update action models, now in widespread use. There is a natural extension of the definition of a bisimulation to action models. Surely enough, updating with bisimilar action models gives the same result (modulo bisimulation). But the converse turns out to be false: update models may have the same update effects without being bisimilar. We propose action emulation as a notion of equivalence more appropriate for action models, and generalizing standard bisimulation. It is proved that action emulation provides a full characterization of update effect. We first concentrate on the general case, and next focus on the important case of action models with propositional preconditions. Our notion of action emulation yields a simplification procedure for action models, and it gives designers of multi-agent systems a useful tool for comparing different ways of representing a particular communicative action.

Published in the Journal of Synthese: Volume 185, Issue 1 (2012), Page 131-151.

• The official version: (need SpringerLink subscription)
  http://www.springerlink.com/openurl.asp?genre=article&id=doi:10.1007/s11229-012-0083-1

  http://www.springerlink.com/content/4414008q2851nkmr/?MUD=MP

• Authors’ final version link. (free to whole world)

Acknowledgements: 

We thank Johan van Benthem, Hans van Ditmarsch, Floor Sietsma, Albert Visser and Yanjing Wang for inspiring discussions, and thank five anonymous reviewers for helpful comments. We are grateful to our editor Wiebe van der Hoek for encouragement, patience, trust and flexibility. The first author is grateful to the Netherlands Institute for Advanced Studies in Wassenaar (NIAS) for providing the opportunity to work on this paper as Fellow-in-Residence.

Bibtex:

@article{AEvanEijckRuanSadzik:2012,
Author = {Jan van Eijck and Ji Ruan and Tomasz Sadzik},
Journal = {Synthese},
Number = {1 (2012)},
Pages = {131-151},
Title = {Action Emulation},
Volume = {185},
Year = {2012}}

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He came from Tinghua Campus on his bike (a typical dutch way)

Here is the complete album:

http://www.flickr.com/photos/jiruan/sets/72157627784013200/

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1. 我将在北大的学术报告：通用游戏竞赛的逻辑 (星期天 25-09-2011) 题目：通用游戏竞赛的逻辑 (Logic for General Game Playing) 主讲人：阮吉 计算机科学和工程学院，新南威尔士大学，澳大利亚 时间：九月二十五日，星期天，晚上8点 地点：哲学系1层会议室...
2. My coming up seminar at Tsinghua University (Friday 23-09-2011) Date: Friday, 23 September, 2011 Location: 清华新斋335 1:30-3:30 PM Speaker:...

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主讲人：阮吉
计算机科学和工程学院，新南威尔士大学，澳大利亚

时间：九月二十五日，星期天，晚上8点
地点：哲学系1层会议室

摘要：通用游戏竞赛GGP（General Game Playing）的目标是创建能自主地学习游戏规则进行游戏比赛的通用智能系统。和1997年打败人类国际象棋冠军的深蓝系统不同的是，通用游戏系统的设计者事先不知道竞赛的具体游戏，而只是被告知所有游戏是用游戏描述语言GDL（Game Description Language）所描述。GDL是一种基于规则的逻辑编程语言。自从2005年通用游戏竞赛在国际人工智能会议AAAI举办以来，已经引起了广泛的兴趣和深入的研究。GDL本身也从只能描述完全信息游戏（例如象棋）扩展到也能描述非完全信息游戏（例如扑克）。我将首先介绍如何对游戏进行描述，然后深入讨论逻辑在游戏推理和刻画中的应用，并展示一些推理复杂性结果。

http://www.phil.pku.edu.cn/cllct/ann_content.php?msgid=215

更新：现场的照片

例子

提问

来自相册：
http://www.flickr.com/photos/jiruan/sets/72157627656865185

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1:30-3:30 PM
Speaker: Patrick Girard
Department of Philosophy, The University of Auckland

Title: Logic in the Communities

Photo Update:

3：30- 5:30 PM
Speaker: Ji Ruan
School of Computer Science and Engineering, The University of New South Wales

Title: A Logic for Knowledge Flow in Social Networks （社交网络中的知识流的逻辑）

Abstract: In this talk, I will present a formal framework for analysing the flow of information and knowledge through social networks. More specifically, we propose a multi-agent epistemic logic in which we can represent and reason about communicative actions based on social networks and the resulting knowledge and ignorance of agents. This logic is applied to formally analyse the “Revolt or Stay-at-home” problem where social networks play an important role in agents’ knowledge acquisition and decision-making. We evaluate our work by proving some mathematical properties of our new logic, including the fact that it generalises the existing Logic of Public Announcement. (This is a joint work with Prof. Michael Thielscher)

Reference Link.

Photo Update:

More photos:
http://www.flickr.com/photos/jiruan/sets/72157627753995408/

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1. Conference paper: A Logic for Knowledge Flow in Social Networks Title: A Logic for Knowledge Flow in Social Networks Authors: Ji Ruan...

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Authors: Ji Ruan and Michael Thielscher
School of Computer Science and Engineering, The University of New South Wales, Australia

Abstract: In this paper, we develop a formal framework for analysing the flow of information and knowledge through social networks. More specifically, we propose a multi-agent epistemic logic in which we can represent and reason about communicative actions based on social networks and the resulting knowledge and ignorance of agents. This logic is applied to formally analyse the “Revolt or Stay-at-home” problem where social networks play an important role in agents’ knowledge acquisition and decision-making. We evaluate our work by proving some mathematical properties of our new logic, including the fact that it generalises the existing Logic of Public Announcement.

Accepted and presented at the 24th Australasian Joint Conference on Artificial Intelligence (AI2011), Perth Australia, December 2011.

Download:

• Springer
• Camera Ready Version.

Bibtex:

@inproceedings{DBLP:conf/ausai/RuanT11,
author = {Ji Ruan and
Michael Thielscher},
title = {A Logic for Knowledge Flow in Social Networks},
booktitle = {Australasian Conference on Artificial Intelligence},
year = {2011},
pages = {511-520},
ee = {http://dx.doi.org/10.1007/978-3-642-25832-9_52},
crossref = {DBLP:conf/ausai/2011},
bibsource = {DBLP, http://dblp.uni-trier.de}
}
@proceedings{DBLP:conf/ausai/2011,
editor = {Dianhui Wang and
Mark Reynolds},
title = {AI 2011: Advances in Artificial Intelligence – 24th Australasian
Joint Conference, Perth, Australia, December 5-8, 2011.
Proceedings},
booktitle = {Australasian Conference on Artificial Intelligence},
publisher = {Springer},
series = {Lecture Notes in Computer Science},
volume = {7106},
year = {2011},
isbn = {978-3-642-25831-2},
ee = {http://dx.doi.org/10.1007/978-3-642-25832-9},
bibsource = {DBLP, http://dblp.uni-trier.de}
}

Related posts:

1. Journal paper: Connecting Dynamic Epistemic and Temporal Epistemic Logics Title: Connecting Dynamic Epistemic and Temporal Epistemic Logics Authors: H.P. van Ditmarsch,...

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Authors: H.P. van Ditmarsch, W. van der Hoek, and J. Ruan.

Abstract: We give a relation between a logic of knowledge and change, with a semantics on Kripke models, and a logic of knowledge and time, with a semantics on interpreted systems. In particular, given an epistemic state (pointed Kripke model with equivalence relations) and a formula in a dynamic epistemic logic (a logic describing the consequences of epistemic actions), we construct an interpreted system relative to that epistemic state and that formula that satisfies the translation of the formula into a temporal epistemic logic. The construction involves that the protocol that is implicit in the dynamic epistemic formula, i.e., the set of sequences of actions being executed to evaluate the formula, is made explicit. We first focus on the logic of knowledge and change that is known as public announcement logic, then generalize our results to a dynamic epistemic logic.

It is published in The Logic Journal of the IGPL.
http://jigpal.oxfordjournals.org/content/early/2011/10/27/jigpal.jzr038.refs

PDF:
http://jigpal.oxfordjournals.org/content/early/2011/10/27/jigpal.jzr038.full.pdf+html

Prepublication version.

It is an extended version of this workshop paper.

The paper was first submitted when I was still at the University of Liverpool (UK) in 2009; the revision was made when I was at the StFX University (Canada) in 2010, and finally accepted when I moved to the current University of New South Wales (Australia) in 2011.

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高铁事故 现场掩埋, originally uploaded by DigiPub.

An English-speaking friend asked me yesterday, why did you talk a lot of politics on Facebook (even sometimes in Chinese)?

Here is a simple answer: my parents and best friends are living in China, which is a high-speed train in a similar type of the ones crashed on 23 July in Wenzhou, China. What the China railway bureau (part of Chinese government) did was digging a big hole and burying the racked train at the second day.

I am not on that train right now, but what about my relatives and friends?

Above photo may not show correctly but here is a copy

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I asked Jing whether she could create an image that serves as a theme image for the website in July (to replace the existing image in the green frame). We had no idea on whether Ai and his colleagues would be released in that month. My point was, no matter what would  happen, we had to prepare for the worst in advance. Jing agreed to give a try and at the same time, she recommended her then roommate ZHANG Rui for an alternative candidate. Two days later, I contacted Rui and she said she was willing to help. And after another day, the world learned that Ai was released on bail. I was, of course, extremely happy about that news (see a picture of me at that moment).

But the story did not stop here. Ai was not allowed to talk to the media about what what he had suffered and some of his colleagues are still missing. That’s why I felt that the website should keep running. I did not contact Jing again about the side bar image since she should spend more time in taking care of her boyfriend WEN tao, who was released shortly after Ai’s release. It was a very long wait for her. I did talk to Rui and I was glad to learn that she was willing to continue working on this. A few days later, she showed me her first two oil paintings with title “Love Ai Weiwei”.

I like her work. The first painting shows clearly a beard face of Ai Weiwei and some shadows of two other unknown figures. The theme color is gray, which associates me with what Ai had been suffered from his 81-day detainment. “Who are those unknown figures?”, I was wondering; they might be the guards or policemen but I did not ask Rui. On July 15, The Washing Post reported that ”the two guards watched Ai Weiwei constantly, never speaking; they stared at him without ever moving their eyes; they stood close by even while he used the toilet; and when he took a shower, they just stood right next to him, even though they were getting totally wet.” Then I suddenly understood. The power of Rui’s work is that it gave out this message at the time that we knew very little about what Ai suffered.

The second painting is a more abstract version of the first one. One can barely recognize Ai’s face or see the guards, but a suspicious eye is clearly visible at the right side. You can imagine that the figure in the center represents not just Ai, but a person like Ai, such as Liu Xiaobo, Ran Yunfei, Wang Lihong and many others, who are fighting for the universal human rights for Chinese people but are detained or imprisoned by the authoritarian government we have in China now. It is wrong to imprison these good souls; it is right to express our true feelings of these good souls. This painting did not end with a negative message. “Love Ai Weiwei” in red font clearly expresses the love and support from the artist and from people like you and me.

These two paintings were published on Loveaiww site (link) on 27 June and the readers loved them as the post was among the top 10 most visited posts of the coming month. Rui was happy about this and she said Ai is an angle and she was planning to paint another one about Ai. She wanted to show what Ai really is and should be. Over the next two weeks, she gave me some updates from time to time. One challenging task she gave me was to give a name for this painting. I thought about it and figured out three:

1. Ai is Love
2. Ai is Love, Love is Ai
3. Ai is Love, Love should be Free

Pinyin is the official system to transcribe Chinese characters into the Roman alphabet, and it is based on pronunciation. In Chinese, the sir name of Ai Weiwei 艾 has the same pronunciation as the character 爱 which means “Love” in English. The reason I have “Ai is Love” in all three options above is very clear: on the one hand Ai Weiwei gives his love to many people by fighting for their rights, and on the other hand, it beautifully connects Chinese Pinyin with English by the same meaning of love. Rui said she had a similar feeling on this and she picked the option 3 finally. By applying Aristotle’s Syllogism upon this title “Ai is Love, Love should be Free”, we can derive that “Ai should be Free”. Ai Weiwei is still not allowed to speak or travel freely, and the recent tax hearing shows that he is even not a major player in the charge. On July 8, Rui published her work on her own blog: http://blog.ruizhang.net/?p=57. And this becomes the new theme image of Loveaiww website.

This shows the yearning for love and freedom. This is the Ai Weiwei I want to see. Art can speak for itself, but I thought that by providing some additional information about the creation of these art works of Rui, you will be able to appreciate more about this young artist and her work.

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Authors:
Ji Ruan and Michael Thielscher
School of Computer Science and Engineering The University of New South Wales, Australia

Abstract:
A general game player automatically learns to play arbitrary new games solely by being told their rules. For this purpose games are specified in the game description language GDL, a variant of Datalog with function symbols and a few known keywords. In its latest version GDL allows to describe nondeterministic games with any number of players who may have imperfect, asymmetric information. We analyse the epistemic structure and expressiveness of this language in terms of epistemic modal logic and present two main results: (1) The operational semantics of GDL entails that the situation at any stage of a game can be characterised by a multi-agent epistemic (i.e., S5-) model; (2) GDL is sufficiently expressive to model any situation that can be described by a (finite) multi- agent epistemic model.

Status:

Presented at the Twenty-Fifth Conference on Artificial Intelligence, AAAI-11. (San Francisco, USA).

Download: Camera Ready Version, AAAI Web Version.

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