waashk/dblp huggingface dataset:
preventing race condition attacks on file-systems. race condition attacks occur when a process performs a sequence of operations on a file, under the assumption that the operations are being executed "atomically". this can be exploited by a malicious process which changes the characteristics of that file between two successive operations on it by a victim process, thus, inducing the victim process to operate on a modified or diflerent file. in this paper we present a practical approach to detect and prevent such race condition attacks. we monitor file operations and enforce policies which prevent the exploitation of the temporal window between any consecutive file operations by a process. our approach does not rely on knowledge of previously known attacks. in addition, our experiments on linux demonstrated that attacks can be detected with false alarms of less than 3% with performance overheads less than 8% of the processes execution time.
an architecture for biological information extraction and representation. technological advances in biomedical research are generating a plethora of heterogeneous data at a high rate. there is a critical need for extraction, integration and management tools for information discovery and synthesis from these heterogeneous data. in this paper, we present a general architecture, called alfa, for information extraction and representation from diverse biological data. the alfa architecture consists of: (i) a networked, hierarchical object model for representing information from heterogeneous data sources in a standardized, structured format; and (ii) a suite of integrated, interactive software tools for information extraction and representation from diverse biological data sources. as part of our research efforts to explore this space, we have currently prototyped the alfa object model and a set of interactive software tools for searching, filtering, and extracting information from scientific text. in particular, we describe bioferret, a meta-search tool for searching and filtering relevant information from the web, and alfa text viewer, an interactive tool for user-guided extraction, disambiguation, and representation of information from scientific text. we further demonstrate the potential of our tools in integrating the extracted information with experimental data and diagrammatic biological models via the common underlying alfa representation.
an anomaly-driven reverse proxy for web applications. careless development of web-based applications results in vulnerable code being deployed and made available to the whole internet, creating easily-exploitable entry points for the compromise of entire networks. to ameliorate this situation, we propose an approach that composes a web-based anomaly detection system with a reverse http proxy. the approach is based on the assumption that a web site's content can be split into security sensitive and non-sensitive parts, which are distributed to different servers. the anomaly score of a web request is then used to route suspicious requests to copies of the web site that do not hold sensitive content. by doing this, it is possible to serve anomalous but benign requests that do not require access to sensitive information, sensibly reducing the impact of false positives. we developed a prototype of our approach and evaluated its applicability with respect to several existing web-based applications, showing that our approach is both feasible and effective.
experimenting with a real-size man-hill to optimize pedagogical paths. this paper describes experiments aimed at adapting ant colony optimization (aco) techniques to an e-learning environment, thanks to the fact that the available on-line material can be organized in a graph by means of hyperlinks between educational topics. the structure of this graph is to be optimized in order to facilitate the learning process for students.aco is based on an ant-hill metaphor. in this case, however, the agents that move on the graph are students who unconsciously leave pheromones in the environment depending on their success or failure. in the paper, the whole process is therefore referred to as a "man-hill."compared to the [13, 14] papers that were providing guidelines for this problem, real-size tests have been performed, showing that man-hills behave differently from ant-hills. the notion of pheromone erosion (rather than evaporation) is introduced.
an authorization model for temporal xml documents. we here describe an access control model for securing temporal xml document. our approach is based on a temporal data model allowing to represent both transactional and valid time dimensions of xml documents. the authorization model allows the specification of temporal conditions on the two considered time dimensions and on the validity of the authorizations.
authenticated multicast immune to denial-of-service attack. authentication of multicast streams has attracted a lot of attention in the last few years. however, two important issues, namely multicast denial-of-service and access control, have been ignored in previous proposals. in this paper, we propose two internet protocol multicast authentication schemes by making use of the multicast tree as an essential authentication mechanism. our schemes are efficient and immune to multicast denial-of-service attack. they allow the receivers to immediately authenticate the packets regardless of the packet loss characteristics of the underlying network.
schemes for sr-tree packing. modern database applications like geographic information systems, multimedia databases, and digital libraries dealing with huge volumes of high dimensional data, make use of multidimensional index structures. among them, sr-tree has been shown to outperform the r-tree and its variants and the ss-tree. for static datasets, packed index structures provide better retrieval performance. this paper presents schemes for sr-tree packing based on different pre-processing techniques. the results show that these schemes consistently outperform packed r-tree and conventional sr-tree structures in terms of storage space and query performance.
intelligent file management in ubiquitous environments. the paradigm of ubiquitous computing seeks to build a computing environment that responds to user context. an ideal file system for the ubiquitous environment is one that can successfully recognize the present context and automate file management. the intelligence in the ubiquitous file management is achieved by applying a heuristics based clustering approach to the system. the applied heuristics are those that are used on file attributes by users to manually manage files in a traditional file system. file attributes can be used to relate files to the most appropriate work-context and also draw inter-file relationships. we discuss methods to harness the given file information from the file-system to form a context-relation wrapper over disparate files. this enables management of files as context related working sets rather than as individual files. a survey was conducted among regular computer users and the compiled results supported our context based file clustering approach. the experiments also showed promising results that confirm our model on the file heuristics, thus finding semantic relations between those files.
nextgen extreme porting: structured by automation. "maintenance is really the normal state of an xp project" - beck. thus porting is a natural candidate for extreme programming and we present a novel tool-based xp methodology for porting c/c++ programs. the structure provided by our tooling is designed for scalability, to enable xp on large projects porting enterprise-scale codebases. overall planning and iteration planning of the methodology are assisted by a novel, first-of-its-kind migration orchestrator tool. automated test, debugging, and audit function are provided as unified support by our refactoring tool framework. we focus on the orchestrator tool and offer preliminary benchmarks with encouraging results.
a framework and analysis for cooperative search using uav swarms. we design and analyze the performance of cooperative search strategies for unmanned aerial vehicles (uavs) searching for moving, possibly evading, targets in a hazardous environment. rather than engaging in independent sensing missions, the sensing agents (uavs with sensors) "work together" by arranging themselves into a flight configuration that optimizes their integrated sensing capability. if a uav is shot down by enemy fire, the team adapts by reconfiguring its topology to optimally continue the mission with the surviving assets. we presetn a cooperative search methodology that integrates the multiple agents into an advantageous formation that distinctively enhances the sensing and detection operations of the system while minimizing the transmission of excessive control information for adaptation of the team's topology. after analyzing our strategy to determine the performance tradeoff between search time and number of uavs employed, we present an algorithm that selects the minimum number of uavs to deploy in order to meet a targeted search time within probabilistic guarantees.
a spatiotemporal uncertainty model of degree 1.5 for continuously changing data objects. to support emerging database applications that deal with continuously changing (or moving) data objects (ccdo), one requires an efficient data management system that can store, update, and retrieve large sets of ccdos. although actual ccdos can continuously change, computer systems cannot deal with continuously occurring infinitesimal changes. thus, in the data management system, each object's spatiotemporal values are always associated with a certain degree of uncertainty at every point in time, and the queries are mostly processed over estimates characterizing the uncertainty. unfortunately, there is a marked lack of formal explication of the uncertainty of multidimensional ccdos in space-time. this paper presents our logical and mathematical bases for capturing, representing, and processing ccdos of varying dimensionality.
a mesh update requirement for hierarchical adaptive meshes in mesh-based motion tracking. this paper presents a mesh update requirement for hierarchical adaptive meshes in mesh-based motion tracking. the requirement states that since hierarchical adaptive meshes are constructed according to the video contents of a predicted frame, constructing a different mesh topology for each predicted frame is necessary in order to most accurately describe the video contents in a predicted frame. it has been statistically verified in the analysis section of this paper that if the requirement is not satisfied, the prediction quality would be lowered. the analysis is performed on different qcif benchmark sequences.
from buddyspace to cititag: large-scale symbolic presence for community building and spontaneous play. in this paper we discuss the conceptual framework and principles that guide our work in the design of large-scale informal environments for collaborative work, learning and play, aiming to foster social bonds and to provide an exciting testbed for emergent social behaviours. we present three different applications we have developed: buddyspace, an instant messaging environment for community building, bumpercars, an online presence-based multiplayer game and cititag, an experimental wireless mixed reality game.
outlier elimination in construction of software metric models. software metric models are models relating various software metrics of software projects. such models' purpose is to predict some of these metrics for certain future projects given the other metrics for those projects. the construction of software metric models derives such relationships and is usually based on data samples of concerned software metrics for past software projects. often, in such a data sample, there are inevitably a few very extreme projects which have relationships among their metrics deviating substantially from those among the metrics for the remaining "mainstream" bulk of projects in the data sample. such "outlier" projects exert considerable undue influence on the derivation of the said relationships during model construction in that the relationships so derived cannot candidly reflect the true "mainstream" relationships. the direct consequence is degraded prediction accuracy of the constructed models for future projects. to overcome this problem, we proposed a methodology to identify and thus eliminate such outliers prior to model construction. our methodology makes use of the least of median squares (lms) regression to uncover such outliers and is applicable irrespective of any subsequent model construction approaches. we also did a case study to apply our methodology, and the results prove our methodology being able to improve the prediction accuracy of most models experimented with in the study. thus, our methodology is recommended for any further software metric model construction. this paper documents such a methodology and the successful case study.
an effective nn search protocol in wireless broadcast environments. data broadcasting provides an effective way to disseminate information in a wireless mobile environment. how to provide the service of k nearest neighbors (knn) search using data broadcasting is studied in this paper. given a data set d and a query point p, the knn search finds k data points in d closest to p. by assuming that the data is indexed by an r-tree, we propose an efficient protocol for knn search on the broadcast r-tree in terms of the tuning time which is the amount of time spent listening to the broadcast, latency which is time elapsed between issuing and termination of the query, and memory usage on the clients. we last validate the proposed protocol by experiments and present our findings.
repweb: replicated web with referential integrity. replication of web content, through mirroring of web sites or browsing off-line content, is one of the most used techniques to increase content availability, reduce network bandwidth usage and minimize browsing delays in the world-wide-web.the world-wide-web does not support referential integrity, i.e., broken links do exist. this has been considered, for some years now, one of the most serious problems of the web. this is true in various fields, e.g.: i) if a user pays for some service in the form of web pages, he requires such pages to be reachable all the time, and ii) archived web resources, either scientific, legal or historic, that are still referenced, need to be preserved and remain available.current approaches to the broken-link problem are not able to preserve referential integrity on the web and, simultaneously, support replication and minimize storage waste due to memory leaks. some of them also impose specific authoring and management systems. thus, the limitations of current systems reside in three issues: transparency, completeness and safety.we propose a system, repweb, comprised of an application to access and manage replicated web content and an implementation of an acyclic distributed garbage collection algorithm for wide-area replicated memory, that satisfies all these requirements. it supports replication, enforces referential integrity on the web and minimizes storage waste.
issues of pedagogy and design in e-learning systems. the purpose of this paper is to discuss some pedagogical issues surrounding e-learning systems. we have been involved in distance education and e-learning for the last 15 years and developed education and training delivered to a wide range of audiences. based on our experiences, results from evaluation studies we conducted, and the literature in the field we provide a constructive critique of lms and discuss some guidelines for future developments of e-learning systems. the emphasis will be on the needs of the online teacher and how these needs can best be supported by the design of appropriate technologies.
improving image retrieval effectiveness in query-by-example environment. query-by-example is the most popular query model for today's image retrieval systems. a typical query image contains not only relevant objects (e.g., eiffel tower), but also irrelevant image areas (e.g., the background). the latter, referred to as noise in this paper, has limited the effectiveness of existing image retrieval systems. we present here a similarity model for noise-free queries (nfqs), and investigate indexing techniques for this new environment. our query model is more expressive than the standard query-by-example. the user can draw a contour around a number of objects to specify spatial (relative distance) and scaling (relative size) constraints among them, or use separate contours to disassociate these objects. our experimental results confirm that traditional approaches, such as local color histogram and correlogram, suffer from noisy queries. in contrast, our method can leverage nfqs to offer significantly better performance. this is achieved using only a fraction of the storage overhead required by the compared techniques.
comparing semantic frameworks for coordination: on the conformance issue for coordination media. a fundamental issue in the engineering of coordination models is to design coordination abstractions that are correct with respect to the specification of the coordination model they implement. the traditional semantic framework for coordination is focused on describing the admissible evolutions over time of a coordinated system, and is particularly suitable for specifying the laws of a coordination model. on the other hand, formally describing run-time aspects of an implementation requires a different framework, capturing as fundamental idea the interactive behavior of a coordination medium.in this paper, these two frameworks are compared by tackling a crucial issue of coordination models, that is, the conformance of an implementation with respect to a specification. in particular, a definition of conformance is introduced that is shown to be compatible with the standard notion of implementation by horizontal refinement promoted in the context of process algebras.
implementing type-based constructive negation. this paper presents an implementation of a constructive negation method. the constructive negation method makes use of type dependencies between arguments of a predicate to rewrite negative goals in a logic program. the constructive negation method is first reformulated as a derivation rule. then an algorithm for efficiently implementing the derivation rule is presented and its complexity is analyzed.
issues in parallelizing multiobjective evolutionary algorithms for real world applications. the concepts of efficiency and effectiveness must be addressed in conducting research into using a evolutionary algorithm (ea) for optimization problems. the increased use of evolutionary approaches for real-world applications, containing multiple objectives and high dimensionality, has led to the design and generation of a number of multiobjective evolutionary algorithms (moea). when analyzing these algorithms, the issues of effectiveness and efficiency are extremely important and typically drive the urge to parallelize these algorithms. the parallelization of moeas is a relatively new concept, with few researchers contributing work in this area. this parallelization process is not a simple task and involves the analysis of various parallel models and the parameters associated with these models. this paper presents a thorough analysis of the various parallel moea models, the issues associated with these models and recommendations for using these models in moeas. in particular, these parallelization concepts are applied to the multiobjective messy genetic algorithm ii.
red with dynamic thresholds for improved fairness. we investigate the fair bandwidth sharing among responsive and unresponsive traffic flows. when these flows compete for the same output link in a router, unresponsive flows tend to occupy more than their fair share of the link capacity. we propose a new active queue management algorithm named random early detection with dynamic thresholds (red-dt) that dynamically adapts queue parameters to achieve a more fair distribution of the link capacity.
a recursive connectionist approach for predicting disulfide connectivity in proteins. we are interested in the prediction of disulfide bridges in proteins, a structural feature that conveys important information about the protein conformation and that can therefore help towards the solution of the folding problem. we assume here that the disulfide bonding state of cysteines is known and we focus on the subsequent problem of disulfide bridges pairings assignment. in this paper, disulfide connectivity is modeled by undirected graphs. a graphspace search algorithm is employed to explore alternative disulfide bridges patterns and prediction consists of selecting the 'best' graph in the search space. the core of the proposed method is a recursive neural network architecture trained to score candidate graphs. we report experiments on previously published data showing that our algorithm outperforms the known alternative methods for most proteins. furthermore, we assess the generalization capabilities testing the model on previously unpublished data.
a java based xml browser for consumer devices. next generation consumer devices will all have an internet connection. thus, one vision is that the future multimedia services will be browser based. extensible markup language (xml) is the most likely markup language. in this paper, we introduce a java based xml browser called x-smiles. it is intended for consumer devices and supports multimedia services. the main advantage of the x-smiles browser is that it supports most of the xml related specifications. different xml based languages can be mixed freely in applications. in addition, the x-smiles has special user interfaces for different kinds of devices (e.g., digital television, personal digital assistants, and mobile phones). these user interfaces can be used as so called virtual prototypes of the real devices. the x-smiles browser is available as open source at http://www.x-smiles.org.
motion estimation performance of the tm3270 processor. motion estimation constitutes a significant computational part of video standards such as mpeg2, mpeg4, and h264/avc. this paper evaluates the performance of a motion estimation algorithm on the tm3270, a low-cost media-processor. in order to improve performance, the tm3270 processor provides architectural enhancements over previous trimedia processors. we quantify the speedup of the proposed new operations to motion estimation performance. we show that the new operations incorporated in the tm3270 improve performance by a factor between 3 and 4. furthermore, we quantify the speedup of data prefetching. we show that prefetching can improve performance up to 30%. by applying all tm3270 architectural enhancements, we show that standard resolution motion estimation can be performed in less than 5% of the available processor performance.
interactive computation and visualization of fetch using standard computer graphics hardware. fetch is a measure of unobstructed wind exposure over open water. depending on prevailing conditions, it may necessitate considering wind exposure from many directions. applications in geography may require visualization of fetch over an entire body of water. impossible by hand and computationally demanding even on a computer, this paper describes a new method which accelerates the process to interactive speeds. the speedup is obtained by reformulating the problem to one of graphics rendering and making use of commonly available computer graphics hardware through opengl, a widely support graphics standard.