33341357
Information Release Control: A Learning-Based Architecture
Modern information system applications involve collaboration in the form of information flow through organization boundaries. Indeed, organizations have vast amounts of information that is shared with other organizations and even the general public for various purposes. In addition to the standard network-level protections, systems usually use some access control mechanisms to protect data. However, access control systems are not designed to deal with deliberate and accidental release of information, to which the user has the authority to access but is not supposed to be released. Moreover, effective access control assumes a perfect categorization of information, which is increasingly difficult in a complex information system. Information release control is viewed as complementary to access control, and aims at restricting the outgoing information flow at the boundary of information systems. This paper presents a general architectural view of a release control system, and discusses the integration in the proposed architecture of a module for learning release control constraints. Continuous learning is applied to adjust the release control constraints in order to reduce both mistakenly released and mistakenly restricted documents. The paper describes in detail the process of learning keyword-based release control constraints.
31223197
Modeling Multilevel Entities Using Single Level Objects
An earlier paper by Jajodia and Kogan [5] introduced an approach for building multilevel secure object-oriented database systems based on a secure message filtering mechanism. Under this approach each object has a unique security level and, therefore, multilevel objects are not supported. In the present paper, we discuss an approach, based on composite objects, that allows multilevel entities to be represented in terms of single level objects. The main qualifying aspect of our approach is that the object interfaces can be provided to users as if multilevel objects were directly supported.
795953
GKMPAN: an efficient group rekeying scheme for secure multicast in ad-hoc networks
We present GKMPAN, an efficient and scalable group rekeying protocol for secure multicast in ad hoc networks. Our protocol exploits the property of ad hoc networks that each member of a group is both a host and a router, and distributes the group key to member nodes via a secure hop-by-hop propagation scheme. A probabilistic scheme based on predeployed symmetric keys is used for implementing secure channels between members for group key distribution. GKMPAN also includes a novel distributed scheme for efficiently updating the predeployed keys. GKMPAN has three attractive properties. First, it is significantly more efficient than group rekeying schemes that were adapted from those proposed for wired networks. Second, GKMPAN has the property of partial statelessness; that is, a node can decode the current group key even if it has missed a certain number of previous group rekeying operations. This makes it very attractive for ad hoc networks where nodes may lose packets due to transmission link errors or temporary network partitions. Third, in GKMPAN the key server does not need any information about the topology of the ad hoc network or the geographic location of the members of the group. We study the security and performance of GKMPAN through detailed analysis and simulation.
6012377
Discovering calendar-based temporal association rules
A temporal association rule is an association rule that holds during specific time intervals. An example is that eggs and coffee are frequently sold together in morning hours. The paper studies temporal association rules during the time intervals specified by user-given calendar schemas. Generally, the use of calendar schemas makes the discovered temporal association rules easier to understand. An example of calendar schema is (year, month, day), which yields a set of calendar-based patterns of the form (d/sub 3/, d/sub 2/, d/sub 1/), where each d/sub i/ is either an integer or the symbol *. For example, (2000, *, 16) is such a pattern, which corresponds to the time intervals, each consisting of the 16th day of a month in year 2000. This paper defines two types of temporal association rules: precise-match association rules require that the association rule holds during every interval, and fuzzy-match ones require that the association rule holds during most of these intervals. The paper extends the well-known a priori algorithm, and also develops two optimization techniques to take advantage of the special properties of the calendar-based patterns. The experiments show that the algorithms and optimization techniques are effective.
17632069
Secure Selective Exclusion in Ad Hoc Wireless Network
A wireless sensor network can be seen as a large number (hundreds of thousand) of small (a few cubic millimetres) devices, battery powered, with very limited hardware resources. Such a network has been studied specifically in the ad hoc model, where the sensors autonomously set up a network infrastructure. We propose here an extension to the current wireless ad hoc sensor network (WSN) model (in particular the base station model), by introducing a Supervisor which has very few interactions with the network, it is mobile in itself, it could have more powerful hardware and it is asynchronous with respect to the sensors. Nevertheless, the Supervisor has to interact with the sensor network, for example to invoke the command to exclude from the network a selected sensor. We believe such a model is particularly suitable for, but not limited to, military applications. We then propose a distributed, cooperative, parallel algorithm for this model that assures the following properties: it enforces both the secure exclusion of a selected compromised sensor from the network and the rekeying of the remaining sensors. It has an overall low overhead both in terms of computation and required transmitted messages. It is scalable, since the algorithm requires only limited, local knowledge of the network topology. Finally, it can be adopted, as an independent layer, to enforce secure exclusion in other models.
28618164
Bootstrapping a data mining intrusion detection system
The application of data mining techniques in intrusion detection has received a lot of attention lately. Most of the approaches require of a training phase based on the availability of labelled data, where the labels indicate whether the points correspond to normal events or attacks. Unfortunately, this labelled data is not readily available in practice. In this paper we present a novel method based in intersecting segments of unlabelled data and using the intersection as the base data for unsupervised learning (clustering). The clustering algorithm, along with a method to find outliers with respect to the base clusters form the basis for separation of unlabelled data into groups of points that are normal (attack-free) and points that correspond to attacks. We show that the technique is very sucessful in separating points of the data sets of the DARPA, Lincoln Labs evaluation of 1999.
13942242
A Scheme of Parallel Processing for MIMD Systems
This paper presents a recognition procedure for parallel tasks in the user program written in a conventional programming language. To establish our program model, it describes the parallelism of the program in tenns of a process flow graph in which the relationships among processes are of predecessors and successors. And finally it presents a parallel processing scheme which realizes automatically the recognition of parallel tasks and schedules these tasks for parallel execution.
21910023
On Universal and Representative Instances for Inconsistent Databases
120699
Enhancements to the Voting Algorithm
There are several consistency control algorithms for managing replicated files in the face of network partitioning due to site or communication link failures. In this paper, we consider the popular voting scheme along with three enhancements: voting with a primary site, dynamic voting, and dynamic voting with linearly ordered copiee. We develop a stochastic model which compares the file availabilities afforded by each of these schemes. We show that in this model dynamic voting with linearly ordered copies provides the greatest availability.
14539530
The Problem of Equivalence for Entity-Relationship Diagrams
We investigate the question of when two entity-relationship diagrams (ERD's) should be considered equivalent, in the sense of representing the same information. This question is very important for a database design process which uses the ERD model, and can be interpreted in various ways. We give three natural and increasingly stricter criteria for developing concepts of equivalence for ERD's. We first give a notion of "domain data compatibility" which ensures that the ERD's in question represent the same universe of data in an aggregate sense. Then we define the set of functional dependencies which are naturally embedded in each ERD, and use it to develop a concept of "data dependency equivalence" which ensures that the ERD's satisfy the same constraints (functional dependencies) among the represented data. Finally, we give our strongest criterion, instance data equivalence, which requires the ERD's to have the same power to represent instances of data. We develop several alternate forms of this third notion, including some giving efficient tableaux tests for its occurrence. Indeed, for each type of equivalence, we give a polynomial-time algorithm to test for it.
1118243
Managing replicated files in partitioned distributed database systems
In this paper, we describe a consistency control algorithm for managing replicated files in the face of network partitioning due to node or communication link failures. It adopts a conservative approach in that mutual consistency among copies of a file is maintained by permitting files to be accessed only in a single partition. Our algorithm has the property that it permits dynamic switching between the “dynamic voting” algorithm and the “linearly ordered copies” algorithm. This aspect is not only appealing but results in greater file availability than in all previously published conservative algorithms.