OpenRaiser/Intern-Atlas huggingface dataset:
Introducing Accountability to Anonymity Networks
Venue: arXiv cs.CR 2013
Year: 2013

Many anonymous communication (AC) networks rely on routing traffic through proxy nodes to obfuscate the originator of the traffic. Without an accountability mechanism, exit proxy nodes risk sanctions by law enforcement if users commit illegal actions through the AC network. We present BackRef, a generic mechanism for AC networks that provides practical repudiation for the proxy nodes by tracing back the selected outbound traffic to the predecessor node (but not in the forward direction) through a cryptographically verifiable chain. It also provides an option for full (or partial) traceability back to the entry node or even to the corresponding user when all intermediate nodes are cooperating. Moreover, to maintain a good balance between anonymity and accountability, the protocol incorporates whitelist directories at exit proxy nodes. BackRef offers improved deployability over the related work, and introduces a novel concept of pseudonymous signatures that may be of independent interest. We exemplify the utility of BackRef by integrating it into the onion routing (OR) protocol, and examine its deployability by considering several system-level aspects. We also present the security definitions for the BackRef system (namely, anonymity, backward traceability, no forward traceability, and no false accusation) and conduct a formal security analysis of the OR protocol with BackRef using ProVerif, an automated cryptographic protocol verifier, establishing the aforementioned security properties against a strong adversarial model.
An Efficient Parallel Solver for SDD Linear Systems
Venue: arXiv cs.NA 2013
Year: 2013

We present the first parallel algorithm for solving systems of linear equations in symmetric, diagonally dominant (SDD) matrices that runs in polylogarithmic time and nearly-linear work. The heart of our algorithm is a construction of a sparse approximate inverse chain for the input matrix: a sequence of sparse matrices whose product approximates its inverse. Whereas other fast algorithms for solving systems of equations in SDD matrices exploit low-stretch spanning trees, our algorithm only requires spectral graph sparsifiers.
Eliminating Network Protocol Vulnerabilities Through Abstraction and Systems Language Design
Venue: arXiv cs.NI 2013
Year: 2013

Incorrect implementations of network protocol message specifications affect the stability, security, and cost of network system development. Most implementation defects fall into one of three categories of well defined message constraints. However, the general process of constructing network protocol stacks and systems does not capture these categorical con- straints. We introduce a systems programming language with new abstractions that capture these constraints. Safe and efficient implementations of standard message handling operations are synthesized by our compiler, and whole-program analysis is used to ensure constraints are never violated. We present language examples using the OpenFlow protocol.
Network Traffic Adaptation For Cloud Games
Venue: arXiv cs.NI 2013
Year: 2013

With the arrival of cloud technology, game accessibility and ubiquity have a bright future; Games can be hosted in a centralize server and accessed through the Internet by a thin client on a wide variety of devices with modest capabilities: cloud gaming. However, current cloud gaming systems have very strong requirements in terms of network resources, thus reducing the accessibility and ubiquity of cloud games, because devices with little bandwidth and people located in area with limited and unstable network connectivity, cannot take advantage of these cloud services. In this paper we present an adaptation technique inspired by the level of detail (LoD) approach in 3D graphics. It delivers multiple platform accessibility and network adaptability, while improving user's quality of experience (QoE) by reducing the impact of poor and unstable network parameters (delay, packet loss, jitter) on game interactivity. We validate our approach using a prototype game in a controlled environment and characterize the user QoE in a pilot experiment. The results show that the proposed framework provides a significant QoE enhancement.
Simulation-based optimization of transportation costs in high pressure gas grid
Venue: arXiv cs.SY 2013
Year: 2013

Design, architecture and deployment details of a decision support system engineered to minimize operating costs of compressor stations in a gas network are presented. The system employs standard simulation software for pipelines, combined with well known optimization routine for finding optimal station control profiles in a repetitive way. A list of custom improvements is presented that make the system capable and robust enough to perform the optimization tasks. Implementation process is described in detail, covering the case of handling extra optimality criteria postulated by the user. Benefits from using the system and lessons learned are presented in the conclusions section.
Describing Textures in the Wild
Venue: arXiv cs.CV 2013
Year: 2013

Patterns and textures are defining characteristics of many natural objects: a shirt can be striped, the wings of a butterfly can be veined, and the skin of an animal can be scaly. Aiming at supporting this analytical dimension in image understanding, we address the challenging problem of describing textures with semantic attributes. We identify a rich vocabulary of forty-seven texture terms and use them to describe a large dataset of patterns collected in the wild.The resulting Describable Textures Dataset (DTD) is the basis to seek for the best texture representation for recognizing describable texture attributes in images. We port from object recognition to texture recognition the Improved Fisher Vector (IFV) and show that, surprisingly, it outperforms specialized texture descriptors not only on our problem, but also in established material recognition datasets. We also show that the describable attributes are excellent texture descriptors, transferring between datasets and tasks; in particular, combined with IFV, they significantly outperform the state-of-the-art by more than 8 percent on both FMD and KTHTIPS-2b benchmarks. We also demonstrate that they produce intuitive descriptions of materials and Internet images.
Performance Evaluation of Java File Security System (JFSS)
Venue: arXiv cs.OS 2013
Year: 2013

Security is a critical issue of the modern file and storage systems, it is imperative to protect the stored data from unauthorized access. We have developed a file security system named as Java File Security System (JFSS) [1] that guarantee the security to files on the demand of all users. It has been developed on Java platform. Java has been used as programming language in order to provide portability, but it enforces some performance limitations. It is developed in FUSE (File System in User space) [3]. Many efforts have been done over the years for developing file systems in user space (FUSE). All have their own merits and demerits. In this paper we have evaluated the performance of Java File Security System (JFSS). Over and over again, the increased security comes at the expense of user convenience, performance or compatibility with other systems. JFSS system performance evaluations show that encryption overheads are modest as compared to security.
Ensemble Relational Learning based on Selective Propositionalization
Venue: arXiv cs.LG 2013
Year: 2013

Dealing with structured data needs the use of expressive representation formalisms that, however, puts the problem to deal with the computational complexity of the machine learning process. Furthermore, real world domains require tools able to manage their typical uncertainty. Many statistical relational learning approaches try to deal with these problems by combining the construction of relevant relational features with a probabilistic tool. When the combination is static (static propositionalization), the constructed features are considered as boolean features and used offline as input to a statistical learner; while, when the combination is dynamic (dynamic propositionalization), the feature construction and probabilistic tool are combined into a single process. In this paper we propose a selective propositionalization method that search the optimal set of relational features to be used by a probabilistic learner in order to minimize a loss function. The new propositionalization approach has been combined with the random subspace ensemble method. Experiments on real-world datasets shows the validity of the proposed method.
Investigating Quality Routing Link Metrics in Wireless Multi-hop Networks
Venue: arXiv cs.NI 2013
Year: 2013

In this paper, we propose a new Quality Link Metric (QLM), ``Inverse Expected Transmission Count (InvETX)'' in Optimized Link State Routing (OLSR) protocol. Then we compare performance of three existing QLMs which are based on loss probability measurements; Expected Transmission Count (ETX), Minimum Delay (MD), Minimum Loss (ML) in Static Wireless Multi-hop Networks (SWMhNs). A novel contribution of this paper is enhancement in conventional OLSR to achieve high efficiency in terms of optimized routing load and routing latency. For this purpose, first we present a mathematical framework, and then to validate this frame work, we select three performance parameters to simulate default and enhanced versions of OLSR. Three chosen performance parameters are; throughput, Normalized Routing Load and End-to-End Delay. From simulation results, we conclude that adjusting the frequencies of topological information exchange results in high efficiency.
On Pole Placement and Invariant Subspaces
Venue: arXiv cs.SY 2013
Year: 2013

The classical eigenvalue assignment problem is revisited in this note. We derive an analytic expression for pole placement which represents a slight generalization of the celebrated Bass-Gura and Ackermann formulae, and also is closely related to the modal procedure of Simon and Mitter.
Deterministic Primality Testing - understanding the AKS algorithm
Venue: arXiv cs.CC 2013
Year: 2013

Prime numbers play a very vital role in modern cryptography and especially the difficulties involved in factoring numbers composed of product of two large prime numbers have been put to use in many modern cryptographic designs. Thus, the problem of distinguishing prime numbers from the rest is vital and therefore there is a need to have efficient primality testing algorithms. Although there had been many probabilistic algorithms for primality testing, there wasn't a deterministic polynomial time algorithm until 2002 when Agrawal, Kayal and Saxena came with an algorithm, popularly known as the AKS algorithm, which could test whether a given number is prime or composite in polynomial time. This project is an attempt at understanding the ingenious idea behind this algorithm and the underlying principles of mathematics that is required to study it. In fact, through out this project, one of the major objectives has been to make it as much self contained as possible. Finally, the project provides an implementation of the algorithm using Software for Algebra and Geometry Experimentation (SAGE) and arrives at conclusions on how practical or otherwise it is.
Optimal Networks from Error Correcting Codes
Venue: arXiv cs.IT 2013
Year: 2013

To address growth challenges facing large Data Centers and supercomputing clusters a new construction is presented for scalable, high throughput, low latency networks. The resulting networks require 1.5-5 times fewer switches, 2-6 times fewer cables, have 1.2-2 times lower latency and correspondingly lower congestion and packet losses than the best present or proposed networks providing the same number of ports at the same total bisection. These advantage ratios increase with network size. The key new ingredient is the exact equivalence discovered between the problem of maximizing network bisection for large classes of practically interesting Cayley graphs and the problem of maximizing codeword distance for linear error correcting codes. Resulting translation recipe converts existent optimal error correcting codes into optimal throughput networks.
Answering SPARQL queries modulo RDF Schema with paths
Venue: arXiv cs.DB 2013
Year: 2013

SPARQL is the standard query language for RDF graphs. In its strict instantiation, it only offers querying according to the RDF semantics and would thus ignore the semantics of data expressed with respect to (RDF) schemas or (OWL) ontologies. Several extensions to SPARQL have been proposed to query RDF data modulo RDFS, i.e., interpreting the query with RDFS semantics and/or considering external ontologies. We introduce a general framework which allows for expressing query answering modulo a particular semantics in an homogeneous way. In this paper, we discuss extensions of SPARQL that use regular expressions to navigate RDF graphs and may be used to answer queries considering RDFS semantics. We also consider their embedding as extensions of SPARQL. These SPARQL extensions are interpreted within the proposed framework and their drawbacks are presented. In particular, we show that the PSPARQL query language, a strict extension of SPARQL offering transitive closure, allows for answering SPARQL queries modulo RDFS graphs with the same complexity as SPARQL through a simple transformation of the queries. We also consider languages which, in addition to paths, provide constraints. In particular, we present and compare nSPARQL and our proposal CPSPARQL. We show that CPSPARQL is expressive enough to answer full SPARQL queries modulo RDFS. Finally, we compare the expressiveness and complexity of both nSPARQL and the corresponding fragment of CPSPARQL, that we call cpSPARQL. We show that both languages have the same complexity through cpSPARQL, being a proper extension of SPARQL graph patterns, is more expressive than nSPARQL.
HEVAL: Yet Another Human Evaluation Metric
Venue: arXiv cs.CL 2013
Year: 2013

Machine translation evaluation is a very important activity in machine translation development. Automatic evaluation metrics proposed in literature are inadequate as they require one or more human reference translations to compare them with output produced by machine translation. This does not always give accurate results as a text can have several different translations. Human evaluation metrics, on the other hand, lacks inter-annotator agreement and repeatability. In this paper we have proposed a new human evaluation metric which addresses these issues. Moreover this metric also provides solid grounds for making sound assumptions on the quality of the text produced by a machine translation.
A Three-class ROC for Evaluating Doubletalk Detectors in Acoustic Echo Cancellation
Venue: arXiv cs.IT 2013
Year: 2013

Doubletalk detector (DTD) is essential to keep adaptive filter from diverging in the presence of near-end speech in acoustic echo cancellation (AEC), and there was a receiver operating characteristic (ROC) to characterize DTD performance. However, the traditional ROC for evaluating DTD used a static time-invariant room acoustic impulse response and could not evaluate DTDs which distinguish echo path change from doubletalk. We solve these problems by extending the traditional binary detection ROC to three class, and simulations show the efficiency of the proposed method.
Enhanced XML Validation using SRML
Venue: arXiv cs.DB 2013
Year: 2013

Data validation is becoming more and more important with the ever-growing amount of data being consumed and transmitted by systems over the Internet. It is important to ensure that the data being sent is valid as it may contain entry errors, which may be consumed by different systems causing further errors. XML has become the defacto standard for data transfer. The XML Schema Definition language (XSD) was created to help XML structural validation and provide a schema for data type restrictions, however it does not allow for more complex situations. In this article we introduce a way to provide rule based XML validation and correction through the extension and improvement of our SRML metalanguage. We also explore the option of applying it in a database as a trigger for CRUD operations allowing more granular dataset validation on an atomic level allowing for more complex dataset record validation rules.
Towards Hybrid Artificial-Slime Mould Devices
Venue: arXiv cs.ET 2013
Year: 2013

The plasmodium of the slime mould Physarum polycephalum has recently received significant attention for its value as a highly malleable amorphous computing substrate. In laboratory-based experiments, micro- and nanoscale artificial circuit components were introduced into the P. polycephalum plasmdodium to investigate the electrical properties and computational abilities of hybridised slime mould. It was found through a combination of imaging techniques and electrophysiological measurements that P. polycephalum is able to internalise a range of electrically active nanoparticles, assemble them in vivo and distribute them around the plasmodium. Hybridised plasmodium is able to form biomorphic mineralised networks, both inside the living plasmodium and the empty trails left in its wake by taxis, both of which facilitate the transmission of electricity. Hybridisation also alters the bioelectrical activity of the plasmodium and likely influences its information processing capabilities. It was concluded that hybridised slime mould is a suitable substrate for producing functional unconventional computing devices.
Duplicate detection methodology for IP network traffic analysis
Venue: arXiv cs.NI 2013
Year: 2013

Network traffic monitoring systems have to deal with a challenging problem: the traffic capturing process almost invariably produces duplicate packets. In spite of this, and in contrast with other fields, there is no scientific literature addressing it. This paper establishes the theoretical background concerning data duplication in network traffic analysis: generating mechanisms, types of duplicates and their characteristics are described. On this basis, a duplicate detection and removal methodology is proposed. Moreover, an analytical and experimental study is presented, whose results provide a dimensioning rule for this methodology.
Ethical considerations in an online community: the balancing act
Venue: arXiv cs.CY 2013
Year: 2013

With the emergence and rapid growth of Social Media, a number of government departments in several countries have embraced Social Media as a privilege channel to interact with their constituency. We are exploring, in collaboration with the Australian Department of Human Services, the possibility to exploit the potential of social networks to support specific groups of citizens. To this end, we have developed Next Step, an online community to help people currently receiving welfare payments find a job and become financially self-sufficient. In this paper, we explore some ethical issues that arise when governments engage directly with citizens, in particular with communities in difficult situations, and when researchers are involved. We describe some of the challenges we faced and how we addressed them. Our work highlights the complexity of the problem, when an online community involves a government department and a welfare recipient group with a dependency relationship with that department. It becomes a balancing act, with the need to ensure privacy of the community members whilst still fulfilling the government's legal responsibilities. While difficult, these issues must be addressed if governments are to engage with their citizens using Social Media.
Off-line Programming and Simulation from CAD Drawings: Robot-Assisted Sheet Metal Bending
Venue: arXiv cs.RO 2013
Year: 2013

Increasingly, industrial robots are being used in production systems. This is because they are highly flexible machines and economically competitive with human labor. The problem is that they are difficult to program. Thus, manufacturing system designers are looking for more intuitive ways to program robots, especially using the CAD drawings of the production system they developed. This paper presents an industrial application of a novel CAD-based off-line robot programming (OLP) and simulation system in which the CAD package used for cell design is also used for OLP and robot simulation. Thus, OLP becomes more accessible to anyone with basic knowledge of CAD and robotics. The system was tested in a robot-assisted sheet metal bending cell. Experiments allowed identifying the pros and cons of the proposed solution.
A Qualitative Representation and Similarity Measurement Method in Geographic Information Retrieval
Venue: arXiv cs.IR 2013
Year: 2013

The modern geographic information retrieval technology is based on quantitative models and methods. The semantic information in web documents and queries cannot be effectively represented, leading to information lost or misunderstanding so that the results are either unreliable or inconsistent. A new qualitative approach is thus proposed for supporting geographic information retrieval based on qualitative representation, semantic matching, and qualitative reasoning. A qualitative representation model and the corresponding similarity measurement method are defined. Information in documents and user queries are represented using propositional logic, which considers the thematic and geographic semantics synthetically. Thematic information is represented as thematic propositions on the base of domain ontology. Similarly, spatial information is represented as geo-spatial propositions with the support of geographic knowledge base. Then the similarity is divided into thematic similarity and spatial similarity. The former is calculated by the weighted distance of proposition keywords in the domain ontology, and the latter similarity is further divided into conceptual similarity and spatial similarity. Represented by propositions and information units, the similarity measurement can take evidence theory and fuzzy logic to combine all sub similarities to get the final similarity between documents and queries. This novel retrieval method is mainly used to retrieve the qualitative geographic information to support the semantic matching and results ranking. It does not deal with geometric computation and is consistent with human commonsense cognition, and thus can improve the efficiency of geographic information retrieval technology.
Nucleation-free $3D$ rigidity
Venue: arXiv cs.CG 2013
Year: 2013

When all non-edge distances of a graph realized in $\mathbb{R}^{d}$ as a {\em bar-and-joint framework} are generically {\em implied} by the bar (edge) lengths, the graph is said to be {\em rigid} in $\mathbb{R}^{d}$. For $d=3$, characterizing rigid graphs, determining implied non-edges and {\em dependent} edge sets remains an elusive, long-standing open problem. One obstacle is to determine when implied non-edges can exist without non-trivial rigid induced subgraphs, i.e., {\em nucleations}, and how to deal with them. In this paper, we give general inductive construction schemes and proof techniques to generate {\em nucleation-free graphs} (i.e., graphs without any nucleation) with implied non-edges. As a consequence, we obtain (a) dependent graphs in $3D$ that have no nucleation; and (b) $3D$ nucleation-free {\em rigidity circuits}, i.e., minimally dependent edge sets in $d=3$. It additionally follows that true rigidity is strictly stronger than a tractable approximation to rigidity given by Sitharam and Zhou \cite{sitharam:zhou:tractableADG:2004}, based on an inductive combinatorial characterization. As an independently interesting byproduct, we obtain a new inductive construction for independent graphs in $3D$. Currently, very few such inductive constructions are known, in contrast to $2D$.