ppxscal/embedding_network huggingface dataset:
WATCHMAN: An Overlay Distributed AAA Architecture for Mobile Ad hoc Networks
Authors: Amir R. Khakpour, Maryline Laurent-Maknavicius, Hakima Chaouchi
Venue: Proceedings of the 2008 Third International Conference on Availability, Reliability and Security (2008)

Access control concerns in MANETs are very serious and considered as a crucial challenge for operators who prospects to employ unrivaled capabilities of such networks for different applications. We propose a novel hierarchical distributed AAA architecture for proactive link state routing protocols notably OLSR [1]. This proposal contains a lightweight and secure design of an overlay authentication and authorization paradigm for mobile nodes as well as a reliable accounting system to enable operators to charge nodes based on their connection duration time. We also suggest a hierarchical distributed AAA (Authentication, Authorization, and Accounting) server architecture with resource and location aware election mechanism. Moreover, this proposal mitigates the OLSR security issues [2] noticeably and eventually defines a node priority-based quality of service.
Efficient Peer Selection in P2P JXTA-Based Platforms
Authors: Fatos Xhafa, Thanasis Daradoumis, Leonard Barolli, Raul Fernandez, Santi Caballe, Vladi Koliqi
Venue: Proceedings of the 22nd International Conference on Advanced Information Networking and Applications (2008)

P2P systems are nowadays being used not only for file sharing but also for developing large-scale distributed applications. As an emerging paradigm for distributed computing, P2P systems are raising important issues as many novel aspects have to be dealt with in such systems. One key issue in P2P distributed computing is the efficient discovery and selection of peers, which is needed for many purposes such as efficient allocation of jobs to peers, load balancing, efficient file transfer, etc. Existing P2P distributed applications use ad hoc ways to discover and selectpeers, usually without any performance guarantee.In this paper we address the problem of the efficient peerselection in P2P distributed platforms. To this end, we havedeveloped a P2P distributed platform using Sun's JXTA technology, which is endowed with resource brokerage strategies to efficiently select peers using four selection models: (a) economic scheduling model; (b) priced-based model; (c) peer-priority selection model; and, (d) random selection model. These different models are aimedto match different needs of P2P applications. Next, we havedeployed the P2P JXTA platform in a real network using nodes of the PlaneLab --a planetary scale distributed infrastructure-- and have experimentally evaluated the performance of the peer selection models by using a distributed application for processinglarge size log files of a virtual campus, which requires bothefficient file transmission and processing in P2P nodes.The results of our work showed the need to develop, implement and evaluate appropriate models for efficient peer selection to match the different requirements of large-scale P2P distributed applications. Although we have used a concrete technology such as JXTA, our approach is applicable in a more general context of P2P and Grid computing domain. Finally, our approach to peer selection through brokerage services is very flexible allowing extensions with other models.
A generalized set theoretic approach for time and space complexity analysis of algorithms and functions
Authors: Ahmed Tarek
Venue: Proceedings of the 10th WSEAS International Conference on APPLIED MATHEMATICS (2006)

There exists a variety of techniques for analyzing the computational complexity of algorithms and functions. This analysis is critical in finding out the upper and the lower bounds on time and space requirements using the big-oh and the big-omega notations. Besides these, there are other complexity criteria, such as, small omega and small o complexities, which are also useful. Complexity analysis is used in selecting an appropriate algorithm for solving a given problem using computer. Unfortunately, most of the existing techniques are complex, obsolete and hard to use in practice. Besides, there is a trend to abuse notational complexities by considering them as functions. However, notational complexities are sets of functions rather than bare functions. In this paper, it has been established that the notational complexities are sets of functions that include all algorithms and functions on the given order satisfying certain constraints. Moreover, starting from the scratch, we show how to determine the time and space complexity functions for a given computational algorithm. We consider application of the proposed framework in determining the notational complexities. The proposed framework may be extended for functions involving multiple variables. Also the space-time bandwidth product has been discussed in deciding the economy of using the computational algorithms.
The role of virtualization in computing education
Authors: Alessio Gaspar, Sarah Langevin, William Armitage, R. Sekar, T. Daniels
Venue: Proceedings of the 39th SIGCSE technical symposium on Computer science education (2008)

Over the past years, many problems related to the system administration of laboratories for undergraduate system-oriented courses have found elegant solutions in the deployment of virtualization suites. This technological advance enabled these courses to switch from a mostly descriptive content to learning activities which engage students in hands-on, authentic, problem-based learning. Since this type of activity requires students to be administrators of their own virtual machines (VM) or even virtual networks, the experience gained is intrinsically authentic. The potential impact on student learning, as compared to simulation or lecture only based setups is worth investigating for laboratories in operating systems, networking, computer security, system administration, etc. We propose to review the increasingly important role that virtualization is playing in computing education from 2 perspectives; (1) Classrooms' system administration and technological advances which support the development of new pedagogies (2) Pedagogical advances which instructors can now implement thanks to these technologies and their impact on students learning from either quantitative or qualitative perspectives The presenters will share their experience leading the Xen Worlds, V-NetLab and SOFTICE projects.
Las Vegas algorithms for matrix groups
Authors: R. Beals
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

We consider algorithms in finite groups, given by a list of generators. We give polynomial time Las Vegas algorithms (randomized, with guaranteed correct output) for basic problems for finite matrix groups over the rationals (and over algebraic number fields): testing membership, determining the order, finding a presentation (generators and relations), and finding basic building blocks: center, composition factors, and Sylow subgroups. These results extend previous work on permutation groups into the potentially more significant domain of matrix groups. Such an extension has until recently been considered intractable. In case of matrix groups G of characteristic p, there are two basic types of obstacles to polynomial-time computation: number theoretic (factoring, discrete log) and large Lie-type simple groups of the same characteristic p involved in the group. The number theoretic obstacles are inherent and appear already in handling abelian groups. They can be handled by moderately efficient (subexponential) algorithms. We are able to locate all the nonabelian obstacles in a normal subgroup N and solve all problems listed above for G/N.
Time-Aware Web Users' Clustering
Authors: Sophia G. Petridou, Vassiliki A. Koutsonikola, Athena I. Vakali, Georgios I. Papadimitriou
Venue: IEEE Transactions on Knowledge and Data Engineering (2008)

Web users clustering is a crucial task for mining information related to users needs and preferences. Up to now, popular clustering approaches build clusters based on usage patterns derived from users' page preferences. This paper emphasizes the need to discover similarities in users' accessing behavior with respect to the time locality of their navigational acts. In this context, we present two time aware clustering approaches for tuning and binding the page and time visiting criteria. The two tracks of the proposed algorithms define clusters with users that show similar visiting behavior at the same time period, by varying the priority given to page or time visiting. The proposed algorithms are evaluated using both synthetic and real datasets and the experimentation has shown that the new clustering schemes result in enriched clusters compared to those created by the conventional non-time aware users clustering approaches. These clusters contain users exhibiting similar access behavior not only in terms of their page preferences but also of their access time.
The integrated use of optical and InSAR data for urban land-cover mapping
Authors: D. Amarsaikhan, M. Ganzorig, P. Ache, H. Blotevogel
Venue: International Journal of Remote Sensing (2007)

The aim of this study is to classify urban land-cover types using the features derived from optical and spaceborne synthetic aperture radar (InSAR) data sets. For the efficient discrimination of the selected classes, a rule-based algorithm that uses the initial image segmentation procedure based on a minimum distance rule and the constraints on spectral parameters and spatial thresholds is constructed. The result of the rule-based method is compared with the results of a standard supervised classification and it demonstrates a higher accuracy. Overall, the research indicates that the integrated features of the optical and InSAR images can significantly improve the classification of land-cover types and the rule-based classification is a powerful tool in the production of a reliable land-cover map.
Reasoning in symbolic computation
Authors: Michael P. Barnett
Venue: ACM Communications in Computer Algebra (2008)

I discuss notations for some styles of mathematical reasoning that include analogy. These notations extend the conventions of the mathematical package mathscape that I reported recently in the Journal of Symbolic Computation. The paper introduces the reasoning objects that I call "precursors" and "consequences lists".
Solving the problem of negative synaptic weights in cortical models
Authors: Christopher Parisien, Charles H. Anderson, Chris Eliasmith
Venue: Neural Computation (2008)

In cortical neural networks, connections from a given neuron are either inhibitory or excitatory but not both. This constraint is often ignored by theoreticians who build models of these systems. There is currently no general solution to the problem of converting such unrealistic network models into biologically plausible models that respect this constraint. We demonstrate a constructive transformation of models that solves this problem for both feedforward and dynamic recurrent networks. The resulting models give a close approximation to the original network functions and temporal dynamics of the system, and they are biologically plausible. More precisely, we identify a general form for the solution to this problem. As a result, we also describe how the precise solution for a given cortical network can be determined empirically.
UQBE: uncertain query by example for web service mashup
Authors: Junichi Tatemura, Songting Chen, Fenglin Liao, Oliver Po, K. Selcuk Candan, Divyakant Agrawal
Venue: Proceedings of the 2008 ACM SIGMOD international conference on Management of data (2008)

The UQBE is a mashup tool for non-programmers that supports query-by-example (QBE) over a schema made up by the user without knowing the schema of the original sources. Based on automated schema matching with uncertainty, the UQBE system returns the best confident results. The system lets the user refine them interactively. A tuple in the query result is associated with lineage that is a boolean formula over schema matching decisions representing underlying conditions on which the corresponding tuple is included in the result. Given binary feedbacks on tuples by the user, which are possibly imprecise, the system solves it as an optimization problem to refine confidence values of matching decisions. The demo features graphical user interaction on the UQBE system, including querying and refinement.
A Service-Oriented Architecture enabling dynamic service grouping for optimizing distributed workflow execution
Authors: Tristan Glatard, Johan Montagnat, David Emsellem, Diane Lingrand
Venue: Future Generation Computer Systems (2008)

In this paper, we describe a Service-Oriented Architecture allowing the optimization of the execution of service workflows. We discuss the advantages of the service-oriented approach with regard to the enactment of scientific applications on a grid infrastructure. Based on the development of a generic Web-Services wrapper, we show how the flexibility of our architecture enables dynamic service grouping for optimizing the application execution time. We demonstrate performance results on a real medical imaging application. On a production grid infrastructure, the optimization proposed introduces a significant speed-up (from 1.2 to 2.9) when compared to a traditional execution.
Adding High-level Reasoning to Efficient Low-level Context Management: A Hybrid Approach
Authors: Daniela Nicklas, Matthias Grossmann, Jorge Mínguez, Matthias Wieland
Venue: Proceedings of the 2008 Sixth Annual IEEE International Conference on Pervasive Computing and Communications (2008)

Rule-based context reasoning is an expressive way to define situations, which are crucial for the implementation of many context-aware applications. Along the scenario of the Conference Guard application we show how this reasoning can be done both by leveraging an efficient context management realized by the Nexus platform) and by a generic rule based service. We present the architecture of the Nexus semantic service, which uses the underlying definition of a low-level context model (the Nexus Augmented World Model) to carry out rules given in first order logic. We realize this service in a straight forward manner by using state-of-the-art softwarecomponents (the Jena 2 framework) and evaluate the number of instances this approach can handle. Our first experiences show that a pre-selection of instances is necessary if the semantic service should work on a largescale context model.
Classification models analysis of internal human population migration in districts
Authors: Křupka Jiří, Kašparová Miloslava
Venue: Proceedings of the 5th WSEAS International Conference on Computational Intelligence, Man-Machine Systems and Cybernetics (2006)

The paper presents a design and an analysis of classifiers for modelling of internal human migration in districts. Classification models are realized by means of supervised methods. Fuzzy inference systems and a hierarchical structure of fuzzy inference system seem to be preferable in terms of modelling. This hierarchical structure can be realized for a great number of fuzzy rules effectively. The population migration is solved for districts in the Czech Republic. Economic and demographic indicators that affect a size of migration are defined. Dependences between indicators are searched by correlation analysis.
Joint Kinetics and Lumbar Curvatures during Symmetric Lifting: Squat and Stoop
Authors: Seonhong Hwang, Youngeun Kim, Youngho Kim
Venue: Proceedings of the 2008 International Conference on BioMedical Engineering and Informatics - Volume 02 (2008)

In this study, joint moments, joint powers, and lumbar lordosis were investigated for two different symmetrical lifting techniques using the three-dimensional motion analysis: squat and stoop. Twentynine male volunteers lifted boxes weighing 5, 10 and 15kg by both squat and stoop lifting techniques. There were no significant differences in maximum lumbar joint moments between two techniques. Ankle, hip and lumbar joints generated power and only knee joint absorbed power in squat lifting, Ankle, knee joints absorbed power and hip, lumbar joints generated power in stoop lifting. At the time of lordotic curvature appearance in squat lifting, strong correlations were found in all three lower extremity joint moments with the lumbar joint. Differently, in stoop lifting, strong correlations existed in hip moment with the lumbar joint. Lordotic angle difference between fluoroscopic images and markers were 6.47±1.02%, 13.01±2.66 degree, and 26.43±5.14 degree by three different calculation methods. In conclusion, considering the correlation with the lumbar joint, the current results suggested that lower limbs contribute to minimize mechanical loading on the waist by the change of lordotic curvature in the lumbar spine for the safe lifting.
Toward best-effort information extraction
Authors: Warren Shen, Pedro DeRose, Robert McCann, AnHai Doan, Raghu Ramakrishnan
Venue: Proceedings of the 2008 ACM SIGMOD international conference on Management of data (2008)

Current approaches to develop information extraction (IE) programs have largely focused on producing precise IE results. As such, they suffer from three major limitations. First, it is often difficult to execute partially specified IE programs and obtain meaningful results, thereby producing a long "debug loop". Second, it often takes a long time before we can obtain the first meaningful result (by finishing and running a precise IE program), thereby rendering these approaches impractical for time-sensitive IE applications. Finally, by trying to write precise IE programs we may also waste a significant amount of effort, because an approximate result -- one that can be produced quickly -- may already be satisfactory in many IE settings. To address these limitations, we propose iFlex, an IE approach that relaxes the precise IE requirement to enable best-effort IE. In iFlex, a developer U uses a declarative language to quickly write an initial approximate IE program P with a possible-worlds semantics. Then iFlex evaluates P using an approximate query processor to quickly extract an approximate result. Next, U examines the result, and further refines P if necessary, to obtain increasingly more precise results. To refine P, U can enlist a next-effort assistant, which suggests refinements based on the data and the current version of P. Extensive experiments on real-world domains demonstrate the utility of the iFlex approach.
Dynamic K-Gram Based Software Birthmark
Authors: Yameng Bai, Xingming Sun, Guang Sun, Xiaohong Deng, Xiaoming Zhou
Venue: Proceedings of the 19th Australian Conference on Software Engineering (2008)

Software theft is a threat for companies that consider code as a core asset. A birthmark can help to prove software theft by identifying intrinsic properties of a program. Two programs with the same birthmark are likely to share a common origin. In this paper, we pro-pose a novel dynamic birthmark. Using a dynamic pro-gram slicing tool with the given input, a union of k-gram instruction-sequence sets denoted as birthmark is used to identify a program uniquely. To evaluate the strength of the birthmarking technique, we compare static k-gram based software birthmark with dynamic approach from similarity with academic obfuscation tools. The result shows that the new birthmark provides both high credibility and resilience. In particular, it proves that the dynamic birthmark is more resilient to semantics-preserving transformations than the static k-gram birthmark.
I-SEAD: A Secure Routing Protocol for Mobile Ad Hoc Networks
Authors: Chu-Hsing Lin, Wei-Shen Lai, Yen-Lin Huang, Mei-Chun Chou
Venue: Proceedings of the 2008 International Conference on Multimedia and Ubiquitous Engineering (2008)

Ad hoc networks are highly dynamic routing networks cooperated by a collection of wireless mobile hosts without any assistance of centralized access point. Secure Efficient Ad hoc Distance Vector (SEAD) is a proactive routing protocol, based on the design of Destination Sequenced Distance Vector routing protocol (DSDV). SEAD provides a robust protocol against attackers trying to create incorrect routing state in other node. However, it does not provide a way to prevent an attacker from tampering the next hop or the destination field in route update. In this paper, we proposed an I-SEAD protocol to solve the problem. A series of simulation experiments are conducted to evaluate the performance.
Impact of priority levels on the efficiency of priority switching
Authors: Karol Molnrár, Pavel Rajmic
Venue: Proceedings of the 4th WSEAS International Conference on Telecommunications and Informatics (2005)

The paper deals with a neural network controlled switch fabric with frame prioritization support. The impact of priority levels on the functionality and efficiency of this switch fabric was deeply investigated. The results of the studies related to the impact of the amount of priority levels are published in this paper.
Performance analysis of two-loop closed production systems
Authors: Na Li, Li Zheng, Quan-Lin Li
Venue: Computers and Operations Research (2009)

A production line with a limited number of carts or pallets is regarded as a closed loop manufacturing system. Such production lines are very useful in various manufacturing systems, such as semiconductor production systems. In this paper, we study a two-loop closed production system by means of block-structured Markov chains, and propose an effective RG-factorization solution to evaluate performance measures of the system, including throughput and WIP level. Based on this, the system can be numerically analyzed with respect to several crucial parameters. This leads to improvement on the design of the carts quantities, which are always crucial factors in closed-loop production lines.
A Comprehensive Approach to Self-Restricted Delegation of Rights in Grids
Authors: Stefan Piger, Christian Grimm, Ralf Groeper, Christopher Kunz
Venue: Proceedings of the 2008 Eighth IEEE International Symposium on Cluster Computing and the Grid (2008)

The delegation of user rights is an essential functionality of GSI-based Grid environments. This mechanism facilitates proxy certificates that are derived from the users' end-entity certificates and enables Grid services to act in the issuing user's name. Currently, the implementation of the GSI forces users to delegate their complete scope of rights. Compromised proxy credentials can thus be used to perform every action users are entitled to. While this is no major issue for traditional Grid communities, it effectively prevents security sensitive communities like medical users from using the Grid. This paper presents a user-based approach to restrict the scope of rights that are delegated by the user. Thus, the risk imposed by compromised proxy credentials is significantly reduced. We define a policy extension for proxy certificates that contains fine-grained authorization policies expressed in XACML. These are used to limit delegated privileges for the access of storage and compute resources. The mechanisms shown in this paper enable users to restrict the delegated rights to the access of specific files on storage resources and to the execution of specific compute jobs. The respective policy enforcement takes place on the gLite IO-Service and the gLite Computing Element. Compatibility to the existing proxy certificate renewal mechanism is preserved by an extension to the MyProxy service. Finally, we present a GridSphere-based graphical front-end that simplifies the process of policy specification and submission of jobs to the Grid.