9276534
Setuid Demystified
7740275
FIREMAN: a toolkit for firewall modeling and analysis
Security concerns are becoming increasingly critical in networked systems. Firewalls provide important defense for network security. However, misconfigurations in firewalls are very common and significantly weaken the desired security. This paper introduces FIREMAN, a static analysis toolkit for firewall modeling and analysis. By treating firewall configurations as specialized programs, FIREMAN applies static analysis techniques to check misconfigurations, such as policy violations, inconsistencies, and inefficiencies, in individual firewalls as well as among distributed firewalls. FIREMAN performs symbolic model checking of the firewall configurations for all possible IP packets and along all possible data paths. It is both sound and complete because of the finite state nature of firewall configurations. FIREMAN is implemented by modeling firewall rules using binary decision diagrams (BDDs), which have been used successfully in hardware verification and model checking. We have experimented with FIREMAN and used it to uncover several real misconfigurations in enterprise networks, some of which have been subsequently confirmed and corrected by the administrators of these networks
43818812
Piecewise linear modulation model of handwriting
A new piecewise linear modulation model of handwriting is proposed. In this model, the velocity of handwriting trajectory is modeled as the impulse response of a time varying second order system. For mathematical tractability, the entire trajectory is segmented into several non-overlapping frames, while the natural frequency and the damping factor of the system are assumed to vary linearly with time in each frame and are continuous along the entire trajectory. In other words, handwriting is regarded as an oscillation modulated by a continuous and piecewise linear signal. The parameters of this model are estimated by Powell's optimization algorithm which does not require the computation of the first order derivative. The number and lengths of the frames are decided by a modified binary search algorithm along with the estimation of parameters. This model has achieved very high data compression rate as well as accurate reproduction of real handwriting.
1194024
Hierarchical classification of Web content
This paper explores the use of hierarchical structure for classifying a large, heterogeneous collection of web content. The hierarchical structure is initially used to train different second-level classifiers. In the hierarchical case, a model is learned to distinguish a second-level category from other categories within the same top level. In the flat non-hierarchical case, a model distinguishes a second-level category from all other second-level categories. Scoring rules can further take advantage of the hierarchy by considering only second-level categories that exceed a threshold at the top level.
We use support vector machine (SVM) classifiers, which have been shown to be efficient and effective for classification, but not previously explored in the context of hierarchical classification. We found small advantages in accuracy for hierarchical models over flat models. For the hierarchical approach, we found the same accuracy using a sequential Boolean decision rule and a multiplicative decision rule. Since the sequential approach is much more efficient, requiring only 14%-16% of the comparisons used in the other approaches, we find it to be a good choice for classifying text into large hierarchical structures.
12433317
Characterization of 1/f noise vs. number of gate stripes in MOS transistors
This paper examines low-frequency 1/f noise (or Bicker noise) in metal oxide semiconductor field-effect transistors (MOSFETs) versus number of gate stripes and bias conditions. Simulations using SPICE/Spectre with Cadence models have displayed the dependence of 1/f noise on the number of gate stripes and the bias conditions. Experimental results from a test chip designed and fabricated in a 0.5 /spl mu/m CMOS process show that 1/f noise is independent of the number of gate stripes in both saturation and linear regions for both P-channel and N-channel devices. The measured results have also shown that 1/f noise is independent of the bias conditions in the saturation region but dependent on the bias conditions in the linear region.
42930138
Evaluating an Infectious Disease Information Sharing and Analysis System
Infectious disease informatics is a subfield of security informatics that focuses on information analysis and management issues critical to the prevention, detection, and management of naturally occurring or terrorist-engineered infectious disease outbreaks. We have developed a research prototype called BioPortal which provides an integrated environment to support cross-jurisdictional and cross-species infectious disease information sharing, integration, analysis, and reporting. This paper reports a pilot study evaluating BioPortal's usability, user satisfaction, and potential impact on practice.
14330906
Creating Context-Aware Software Agents
Sharing ontologies, sensing context and reasoning are crucial to the realization of context-aware software agents. This document de- scribes our efforts in using the Resource Description Framework (RDF) and Prolog Forward Chaining (Pfc) system to provide support for ontology sharing and reasoning in the CoolAgent Recommendation System (CoolAgent RS), a context-aware multi-agent system. We also describes the implementation of the CoolAgent RS document and cuisine recommendation services that provide tailored services by exploiting user's context.
34921454
Cognitive process as a basis for intelligent retrieval systems design
Abstract Two studies were conducted to investigate the cognitive processes involved in online document-based information retrieval. These studies led to the development of five computational models of online document retrieval. These models were then incorporated into the design of an “intelligent” document-based retrieval system. Following a discussion of this system, we discuss the broader implications of our research for the design of information retrieval systems.
8713624
Intelligent agents meet semantic web in a smart meeting room
We describe a new smart meeting room system called EasyMeeting that explores the use of FIPA agent technologies, Semantic Web ontologies, logic reasoning, and security and privacy policies. Building on a pervasive computing system that we have developed previously, EasyMeeting can provide relevant services and information to meeting participants based on their situational needs. Our system exploits the context-aware support provided by the Context Broker Architecture (CoBrA). Central to CoBrA is an intelligent broker agent that maintains a shared model of context for all computing entities in the space and enforces the privacy policies defined by the users. We also describe the use of CoBrA ontologies, logic reasoning, and privacy protection mechanisms, and evaluate our initial user experience studies.