OpenRaiser/Intern-Atlas huggingface dataset:
Bounded Languages Meet Cellular Automata with Sparse Communication
Venue: arXiv cs.FL 2009
Year: 2009

Cellular automata are one-dimensional arrays of interconnected interacting finite automata. We investigate one of the weakest classes, the real-time one-way cellular automata, and impose an additional restriction on their inter-cell communication by bounding the number of allowed uses of the links between cells. Moreover, we consider the devices as acceptors for bounded languages in order to explore the borderline at which non-trivial decidability problems of cellular automata classes become decidable. It is shown that even devices with drastically reduced communication, that is, each two neighboring cells may communicate only constantly often, accept bounded languages that are not semilinear. If the number of communications is at least logarithmic in the length of the input, several problems are undecidable. The same result is obtained for classes where the total number of communications during a computation is linearly bounded.
Capacity Bounded Grammars and Petri Nets
Venue: arXiv cs.FL 2009
Year: 2009

A capacity bounded grammar is a grammar whose derivations are restricted by assigning a bound to the number of every nonterminal symbol in the sentential forms. In the paper the generative power and closure properties of capacity bounded grammars and their Petri net controlled counterparts are investigated.
A Note on the Power of Truthful Approximation Mechanisms
Venue: arXiv cs.GT 2009
Year: 2009

We study the power of polynomial-time truthful mechanisms comparing to polynomial time (non-truthful) algorithms. We show that there is a setting in which deterministic polynomial-time truthful mechanisms cannot guarantee a bounded approximation ratio, but a non-truthful FPTAS exists. We also show that in the same setting there is a universally truthful mechanism that provides an approximation ratio of 2. This shows that the cost of truthfulness is unbounded. The proofs are almost standard in the field and follow from known results.
Providing Secrecy With Structured Codes: Tools and Applications to Two-User Gaussian Channels
Venue: arXiv cs.IT 2009
Year: 2009

Recent results have shown that structured codes can be used to construct good channel codes, source codes and physical layer network codes for Gaussian channels. For Gaussian channels with secrecy constraints, however, efforts to date rely on random codes. In this work, we advocate that structured codes are useful for providing secrecy, and show how to compute the secrecy rate when structured codes are used. In particular, we solve the problem of bounding equivocation rates with one important class of structured codes, i.e., nested lattice codes. Having established this result, we next demonstrate the use of structured codes for secrecy in two-user Gaussian channels. In particular, with structured codes, we prove that a positive secure degree of freedom is achievable for a large class of fully connected Gaussian channels as long as the channel is not degraded. By way of this, for these channels, we establish that structured codes outperform Gaussian random codes at high SNR. This class of channels include the two-user multiple access wiretap channel, the two-user interference channel with confidential messages and the two-user interference wiretap channel. A notable consequence of this result is that, unlike the case with Gaussian random codes, using structured codes for both transmission and cooperative jamming, it is possible to achieve an arbitrary large secrecy rate given enough power.
Key Distribution Scheme without Deployment Knowledge
Venue: arXiv cs.CR 2009
Year: 2009

Many basic key distribution schemes specifically tuned to wireless sensor networks have been proposed in the literature. Recently, several researchers have proposed schemes in which they have used group-based deployment models and assumed predeployment knowledge of the expected locations of nodes. They have shown that these schemes achieve better performance than the basic schemes, in terms of connectivity, resilience against node capture and storage requirements. But in many situations expected locations of nodes are not available. In this paper we propose a solution which uses the basic scheme, but does not use group-based deployment model and predeployment knowledge of the locations of nodes, and yet performs better than schemes which make the aforementioned assumptions. In our scheme, groups are formed after deployment of sensor nodes, on the basis of their physical locations, and the nodes sample keys from disjoint key pools. Compromise of a node affects secure links with other nodes that are part of its group only. Because of this reason, our scheme performs better than the basic schemes and the schemes using predeployment knowledge, in terms of connectivity, storage requirement, and security. Moreover, the post-deployment key generation process completes sooner than in schemes like LEAP+.
Optimal Angular Resolution for Face-Symmetric Drawings
Venue: arXiv cs.DS 2009
Year: 2009

Let G be a graph that may be drawn in the plane in such a way that all internal faces are centrally symmetric convex polygons. We show how to find a drawing of this type that maximizes the angular resolution of the drawing, the minimum angle between any two incident edges, in polynomial time, by reducing the problem to one of finding parametric shortest paths in an auxiliary graph. The running time is at most O(t^3), where t is a parameter of the input graph that is at most O(n) but is more typically proportional to n^.5.
Decoding Finger Flexion using amplitude modulation from band-specific ECoG
Venue: arXiv cs.HC 2009
Year: 2009

EEG-BCIs have been well studied in the past decades and implemented into several famous applications, like P300 speller and wheelchair controller. However, these interfaces are indirect due to low spatial resolution of EEG. Recently, direct ECoG-BCIs attract intensive attention because ECoG provides a higher spatial resolution and signal quality. This makes possible localization of the source of neural signals with respect to certain brain functions. In this article, we present a realization of ECoG-BCIs for finger flexion prediction provided by BCI competition IV. Methods for finger flexion prediction including feature extraction and selection are provided in this article. Results show that the predicted finger movement is highly correlated with the true movement when we use band-specific amplitude modulation.
A preliminary XML-based search system for planetary data
Venue: arXiv cs.IR 2009
Year: 2009

Planetary sciences can benefit from several different sources of information, i.e. ground-based or near Earth-based observations, space missions and laboratory experiments. The data collected from these sources, however, are spread over a number of smaller, separate communities and stored through different facilities: this makes it difficult to integrate them. The IDIS initiative, born in the context of the Europlanet project, performed a pilot study of the viability and the issues to be overcome in order to create an integrated search system for planetary data. As part of the results of such pilot study, the IDIS Small Bodies and Dust node developed a search system based on a preliminary XML data model. Here we introduce the goals of the IDIS initiative and describe the structure and the working of this search system. The source code of the search system is released under GPL license to allow people interested in participating to the IDIS initiative both as developers and as data providers to familiarise with the search environment and to allow the creation of volunteer nodes to be integrated into the existing network.
Keys through ARQ
Venue: arXiv cs.IT 2009
Year: 2009

This paper develops a novel framework for sharing secret keys using the well-known Automatic Repeat reQuest (ARQ) protocol. The proposed key sharing protocol does not assume any prior knowledge about the channel state information (CSI), but, harnesses the available opportunistic secrecy gains using only the one bit feedback, in the form of ACK/NACK. The distribution of key bits among multiple ARQ epochs, in our approach, allows for mitigating the secrecy outage phenomenon observed in earlier works. We characterize the information theoretic limits of the proposed scheme, under different assumptions on the channel spatial and temporal correlation function, and develop low complexity explicit implementations. Our analysis reveals a novel role of "dumb antennas" in overcoming the negative impact of spatial correlation, between the legitimate and eavesdropper channels, on the achievable secrecy rates. We further develop an adaptive rate allocation policy which achieves higher secrecy rates by exploiting the channel temporal correlation. Finally, our theoretical claims are validated by numerical results that establish the achievability of non-zero secrecy rates even when the eavesdropper channel is less noisy, on the average, than the legitimate channel.
Log Management support for recovery in mobile computing Environment
Venue: arXiv cs.NI 2009
Year: 2009

Rapid and innovative improvement in wireless communication technologies has led to an increase in the demand for mobile internet transactions. However, internet access from mobile devices is very expensive due to limited bandwidth available on wireless links and high mobility rate of mobile hosts. When a user executes a transaction with a web portal from a mobile device, the disconnection necessitates failure of the transaction or redoing all the steps after reconnection, to get back into consistent application state. Thus considering challenges in wireless mobile networks, a new log management scheme is proposed for recovery of mobile transactions. In this proposed approach, the model parameters that affect application state recovery are analyzed. The proposed scheme is compared with the existing Lazy and Pessimistic scheme and a trade off analysis between the cost invested to manage log and the return of investment in terms of improved failure recoverability is made. From the analysis, the best checkpoint interval period that yields the best return of investment is identified.
A Class of DSm Conditional Rules
Venue: arXiv cs.AI 2009
Year: 2009

In this paper we introduce two new DSm fusion conditioning rules with example, and as a generalization of them a class of DSm fusion conditioning rules, and then extend them to a class of DSm conditioning rules.
Complete Security Framework for Wireless Sensor Networks
Venue: arXiv cs.CR 2009
Year: 2009

Security concern for a Sensor Networks and level of security desired may differ according to application specific needs where the sensor networks are deployed. Till now, most of the security solutions proposed for sensor networks are layer wise i.e a particular solution is applicable to single layer itself. So, to integrate them all is a new research challenge. In this paper we took up the challenge and have proposed an integrated comprehensive security framework that will provide security services for all services of sensor network. We have added one extra component i.e. Intelligent Security Agent (ISA) to assess level of security and cross layer interactions. This framework has many components like Intrusion Detection System, Trust Framework, Key Management scheme and Link layer communication protocol. We have also tested it on three different application scenarios in Castalia and Omnet++ simulator.
An Improvement of Cover/El Gamal's Compress-and-Forward Relay Scheme
Venue: arXiv cs.IT 2009
Year: 2009

The compress-and-forward relay scheme developed by (Cover and El Gamal, 1979) is improved with a modification on the decoding process. The improvement follows as a result of realizing that it is not necessary for the destination to decode the compressed observation of the relay; and even if the compressed observation is to be decoded, it can be more easily done by joint decoding with the original message, rather than in a successive way. An extension to multiple relays is also discussed.
A Formalization of the Semantics of Functional-Logic Programming in Isabelle
Venue: arXiv cs.LO 2009
Year: 2009

Modern functional-logic programming languages like Toy or Curry feature non-strict non-deterministic functions that behave under call-time choice semantics. A standard formulation for this semantics is the CRWL logic, that specifies a proof calculus for computing the set of possible results for each expression. In this paper we present a formalization of that calculus in the Isabelle/HOL proof assistant. We have proved some basic properties of CRWL: closedness under c-substitutions, polarity and compositionality. We also discuss some insights that have been gained, such as the fact that left linearity of program rules is not needed for any of these results to hold.
IPv6 and IPv4 Threat reviews with Automatic Tunneling and Configuration Tunneling Considerations Transitional Model:A Case Study for University of Mysore Network
Venue: arXiv cs.NI 2009
Year: 2009

The actual transition from IPv4 to IPv6 requires network administrators to become aware of the next generation protocol and the associated risk problems.Due to the scale and complexity of current internet architecture how to protect from the existing investment and reduce the negative influence to users and service providers during the transition from IPv4 to IPv6 is a very important future topic for the advanced version of an internet architecture.This paper summarizes and compares the IPv6 transition mechanism methods like Dual Stack,Tunneling issues like IPv6 Automatic tunneling and manually configured tunneling considerations, the IPv6 transition scenarios,IPv6 transition security problems,highlights IPv6 and IPv4 threat review with automatic tunneling and configuration tunneling considerations.In this paper we have proposed a transitional threat model for automatic tunneling and a configuration tunneling that could be followed by the University of Mysore(UoM),to estimate automatic tunneling and a manually configured tunneling threat review issues.Furthermore,there are different tunneling mechanisms such as IPv6 over IPv4 GRE Tunnel,Tunnel broker,Automatic IPv4 Compatible Tunnel and Automatic 6 to 4 Tunnel and also outlines many of the common known threats against IPv6 and then it compares and contrast how these threats are similar ones,might affect an IPv6 network.
Interworking Scheme Using Optimized SIP Mobility for MultiHomed Mobile Nodes in Wireless Heterogeneous Networks
Venue: arXiv cs.NI 2009
Year: 2009

Nowadays, mobile users wish to use their multi-interface mobile devices to access the Internet through network points of attachment (PoA) based on heterogeneous wireless technologies. They also wish to seamlessly change the PoAs during their ongoing sessions to improve service quality and/or reduce monetary cost. If appropriately handled, multihomed mobile nodes offer a potential solution to this issue. In this sense, the management of multihomed mobile nodes in heterogeneous environment is a key research topic. In this paper, we present an improvement of SIP mobility (pre-call plus mid-call mobility) to support seamless mobility of multihomed mobile nodes in heterogeneous wireless networks. Pre-call mobility is extended to associate user identifier (i.e. SIP URI) and interface identifiers (i.e. IP addresses). The multiple addresses of a mobile device are weighted by the user to create a priority list in the SIP server so as to guarantee resilient reachability of mobile nodes and to avoid unnecessary signaling through wireless links, thus saving radio resources. Then, three variations of mid-call mobility, called hard, hybrid and soft procedures, are also proposed. Their main aim is to minimize, or even avoid, packet losses during interface switching at the mobile node. The proposed solutions have been implemented in a wireless heterogeneous testbed composed of 802.11 WLAN plus 3.5 cellular network, which are fully controlled and configurable. The testbed has been used to study the performance and the robustness of the three proposed mid-call mobility procedures.
News from the Internet congestion control world
Venue: arXiv cs.NI 2009
Year: 2009

A few months ago, the BitTorrent developers announced that the transfer of torrent data in the official client was about to switch to uTP, an application-layer congestion-control protocol using UDP at the transport-layer. This announcement immediately raised an unmotivated buzz about a new, imminent congestion collapse of the whole Internet. Though this reaction was not built on solid technical foundation, nevertheless a legitimate question remains: i.e., whether this novel algorithm is a necessary building block for future Internet applications, or whether it may result in an umpteenth addition to the already well populated world of Internet congestion control algorithms. In this paper, we tackle precisely this issue. The novel protocol is now under discussion at the IETF LEDBAT working group, and has been defined in a draft document in March 2009, whose adoption decision will be taken at the beginning of August 2009. Adhering to the IETF draft definition, we implement the LEDBAT congestion control algorithm and investigate its performance by means of packet-level simulations. Considering a simple bottleneck scenario where LEDBAT competes against either TCP or other LEDBAT flows, we evaluate the fairness of the resource share as well as its efficiency. Our preliminary results show that indeed, there is an undoubted appeal behind the novel application-layer congestion-control protocol. Yet, care must be taken in order to ensure that some important points, such as intra-protocol fairness, are fully clarified in the draft specification -- which we hope that this work can contribute to.
Nuzzer: A Large-Scale Device-Free Passive Localization System for Wireless Environments
Venue: arXiv cs.NI 2009
Year: 2009

The widespread usage of wireless local area networks and mobile devices has fostered the interest in localization systems for wireless environments. The majority of research in the context of wireless-based localization systems has focused on device-based active localization, in which a device is attached to tracked entities. Recently, device-free passive localization (DfP) has been proposed where the tracked entity is neither required to carry devices nor participate actively in the localization process. DfP systems are based on the fact that RF signals are affected by the presence of people and objects in the environment. The DfP concept enables a wide range of applications including intrusion detection and tracking, border protection, and smart buildings automation. Previous studies have focused on small areas with direct line of sight and/or controlled environments. In this paper, we present the design, implementation and analysis of Nuzzer, a large-scale device-free passive localization system for real environments. Without any additional hardware, it makes use of the already installed wireless data networks to monitor and process changes in the received signal strength (RSS) transmitted from access points at one or more monitoring points. We present probabilistic techniques for DfP localization and evaluate their performance in a typical office building, rich in multipath, with an area of 1500 square meters. Our results show that the Nuzzer system gives device-free location estimates with less than 2 meters median distance error using only two monitoring laptops and three access points. This indicates the suitability of Nuzzer to a large number of application domains.
A New Scheme for Minimizing Malicious Behavior of Mobile Nodes in Mobile Ad Hoc Networks
Venue: arXiv cs.CR 2009
Year: 2009

The performance of Mobile Ad hoc networks (MANET) depends on the cooperation of all active nodes. However, supporting a MANET is a cost-intensive activity for a mobile node. From a single mobile node perspective, the detection of routes as well as forwarding packets consume local CPU time, memory, network-bandwidth, and last but not least energy. We believe that this is one of the main factors that strongly motivate a mobile node to deny packet forwarding for others, while at the same time use their services to deliver its own data. This behavior of an independent mobile node is commonly known as misbehaving or selfishness. A vast amount of research has already been done for minimizing malicious behavior of mobile nodes. However, most of them focused on the methods/techniques/algorithms to remove such nodes from the MANET. We believe that the frequent elimination of such miss-behaving nodes never allowed a free and faster growth of MANET. This paper provides a critical analysis of the recent research wok and its impact on the overall performance of a MANET. In this paper, we clarify some of the misconceptions in the understating of selfishness and miss-behavior of nodes. Moreover, we propose a mathematical model that based on the time division technique to minimize the malicious behavior of mobile nodes by avoiding unnecessary elimination of bad nodes. Our proposed approach not only improves the resource sharing but also creates a consistent trust and cooperation (CTC) environment among the mobile nodes. The simulation results demonstrate the success of the proposed approach that significantly minimizes the malicious nodes and consequently maximizes the overall throughput of MANET than other well known schemes.
A multidimensional approach for context-aware recommendation in mobile commerce
Venue: arXiv cs.CY 2009
Year: 2009

Context as the dynamic information describing the situation of items and users and affecting the users decision process is essential to be used by recommender systems in mobile commerce to guarantee the quality of recommendation. This paper proposes a novel multidimensional approach for context aware recommendation in mobile commerce. The approach represents users, items, context information and the relationship between them in a multidimensional space. It then determines the usage patterns of each user under different contextual situations and creates a new 2 dimensional recommendation space and does the final recommendation in that space. This paper also represents an evaluation process by implementing the proposed approach in a restaurant food recommendation system considering day, time, weather and companion as the contextual information and comparing the approach with the traditional 2 dimensional one. The results of comparison illustrates that the multidimensional approach increases the recommendation quality.
Beamforming and Rate Allocation in MISO Cognitive Radio Networks
Venue: arXiv cs.IT 2009
Year: 2009

We consider decentralized multi-antenna cognitive radio networks where secondary (cognitive) users are granted simultaneous spectrum access along with license-holding (primary) users. We treat the problem of distributed beamforming and rate allocation for the secondary users such that the minimum weighted secondary rate is maximized. Such an optimization is subject to (1) a limited weighted sum-power budget for the secondary users and (2) guaranteed protection for the primary users in the sense that the interference level imposed on each primary receiver does not exceed a specified level. Based on the decoding method deployed by the secondary receivers, we consider three scenarios for solving this problem. In the first scenario each secondary receiver decodes only its designated transmitter while suppressing the rest as Gaussian interferers (single-user decoding). In the second case each secondary receiver employs the maximum likelihood decoder (MLD) to jointly decode all secondary transmissions, and in the third one each secondary receiver uses the unconstrained group decoder (UGD). By deploying the UGD, each secondary user is allowed to decode any arbitrary subset of users (which contains its designated user) after suppressing or canceling the remaining users.