7957934
A systematic classification of cheating in online games
Cheating is rampant in current game play on the Internet. However, it is not as well understood as one might expect. In this paper, we summarize the various known methods of cheating, and we define a taxonomy of online game cheating with respect to the underlying vulnerability (what is exploited?), consequence (what type of failure can be achieved?) and the cheating principal (who is cheating?). This taxonomy provides a systematic introduction to the characteristics of cheats in online games and how they can arise. It is intended to be comprehensible and useful not only to security specialists, but also to game developers, operators and players who are less knowledgeable and experienced in security. One of our findings is that although cheating in online games is largely due to various security failures, the four traditional aspects of security -- confidentiality, integrity, availability and authenticity -- are insufficient to explain it. Instead, fairness becomes a vital additional aspect, and its enforcement provides a convincing perspective for understanding the role of security techniques in developing and operating online games.
14117241
Denial of Service: Another Example
Although denial of service attack has been becoming a fast-growing concern in security research, previous work focused on a type of classical denial of service caused by resource exhaustion. In this paper, a different type of network denial of service attack is discussed. Since traditional models and countermeasures are not applicable, we discuss solutions that can defend this non-classical service denial attack.
132181
A note on proactive password checking
Nowadays, proactive password checking algorithms are based on the philosophy of the dictionary attack, and they often fail to prevent some weak passwords with low entropy. In this paper, a new approach is proposed to deal with this new class of weak passwords by (roughly) measuring entropy. A simple example is given to exploit effective patterns to prevent low-entropy passwords as the first step of entropy-based proactive password checking.
206485325
Password memorability and security: empirical results
Users rarely choose passwords that are both hard to guess and easy to remember. To determine how to help users choose good passwords, the authors performed a controlled trial of the effects of giving users different kinds of advice. Some of their results challenge the established wisdom.
4689080
Local Discontinuous Galerkin Methods for Partial Differential Equations with Higher Order Derivatives
In this paper we review the existing and develop new local discontinuous Galerkin methods for solving time dependent partial differential equations with higher order derivatives in one and multiple space dimensions. We review local discontinuous Galerkin methods for convection diffusion equations involving second derivatives and for KdV type equations involving third derivatives. We then develop new local discontinuous Galerkin methods for the time dependent bi-harmonic type equations involving fourth derivatives, and partial differential equations involving fifth derivatives. For these new methods we present correct interface numerical fluxes and prove L2 stability for general nonlinear problems. Preliminary numerical examples are shown to illustrate these methods. Finally, we present new results on a post-processing technique, originally designed for methods with good negative-order error estimates, on the local discontinuous Galerkin methods applied to equations with higher derivatives. Numerical experiments show that this technique works as well for the new higher derivative cases, in effectively doubling the rate of convergence with negligible additional computational cost, for linear as well as some nonlinear problems, with a local uniform mesh.
4917474
Effective Visualisation of Workflow Enactment
Although most existing teamwork management systems support user-friendly interface to some extent, few of them have take into consideration of the special requirements of workflow visualisation. This paper realises the unique features of visualisation for run-time workflow, i.e., workflow enactment and execution. We present a detailed discussion of the emerging problems against the general aesthetic criteria for drawing the workflow layout. In order to support most essential workflow enactment facilities, the following three mechanisms are provided. Firstly, Sugiyama algorithm has been systematically incorporated into our prototype to create well structured workflow layout initially. Secondly, when the workflow process dynamically changes, we can adjust workflow layout by our force-scan algorithm to retain the mental maps created earlier among team members. Thirdly, we have also applied the technique of the fisheye view to offer a context focus mechanism for workflow users and to utilise the screen size more effectively. With these visualisation techniques, a better atmosphere may be facilitated for teamwork.
16598523
Algorithmic Aspects of the Generalized Clique-transversal Problem on Chordal Graphs
Suppose G = (V, E) is a graph in which each maximal clique Ci is associated with an integer ri, where 0 ⩽ ri ⩽ ¦Ci¦. The generalized clique transversal problem is to determine the minimum cardinality of a subset D of V such that ¦D ∩ Ci¦ ⩾ ri for every maximal clique Ci of G. The problem includes the clique-transversal problem, the i, 1 clique-cover problem, and for perfect graphs, the maximum q-colorable subgraph problems as special cases. This paper gives complexity results for the problem on subclasses of chordal graphs, e.g., strongly chordal graphs, k-trees, split graphs, and undirected path graphs.
5296157
A Novel Scalable Algorithm for Supervised Subspace Learning
Subspace learning approaches aim to discover important statistical distribution on lower dimensions for high dimensional data. Methods such as principal component analysis (PCA) do not make use of the class information, and linear discriminant analysis (LDA) could not be performed efficiently in a scalable way. In this paper, we propose a novel highly scalable supervised subspace learning algorithm called as supervised Kampong measure (SKM). It assigns data points as close as possible to their corresponding class mean, simultaneously assigns data points to be as far as possible from the other class means in the transformed lower dimensional subspace. Theoretical derivation shows that our algorithm is not limited by the number of classes or the singularity problem faced by LDA. Furthermore, our algorithm can be executed in an incremental manner in which learning is done in an online fashion as data streams are received. Experimental results on several datasets, including a very large text data set RCV1, show the outstanding performance of our proposed algorithm on classification problems as compared to PCA, LDA and a popular feature selection approach, information gain (IG).
38959890
The bandwidth sum of join and composition of graphs
Given a graph G, a proper labeling f of G is a one-to-one function f:V(G)->{1,2,...,|V(G)|}. The bandwidth sum of a graph G, denoted by B"s(G), is defined by B"s(G)=min@?"u"v"@?"E"("G")|f(u)-f(v)|, where the minimum is taken for all proper labelings f of G. In this paper, we give some results for the bandwidth sum problem for the join of k graphs G"1,G"2,...,G"k, where each G"i is a path, cycle, complete graph, or union of isolated vertices. We also discuss the bandwidth sum for the composition of two graphs G and H, where G and H are path, cycle, or union of isolated vertices.