OpenRaiser/Intern-Atlas huggingface dataset:
Optimizing Password Composition Policies
Venue: arXiv cs.CR 2013
Year: 2013

A password composition policy restricts the space of allowable passwords to eliminate weak passwords that are vulnerable to statistical guessing attacks. Usability studies have demonstrated that existing password composition policies can sometimes result in weaker password distributions; hence a more principled approach is needed. We introduce the first theoretical model for optimizing password composition policies. We study the computational and sample complexity of this problem under different assumptions on the structure of policies and on users' preferences over passwords. Our main positive result is an algorithm that -- with high probability --- constructs almost optimal policies (which are specified as a union of subsets of allowed passwords), and requires only a small number of samples of users' preferred passwords. We complement our theoretical results with simulations using a real-world dataset of 32 million passwords.
Constructing Polar Codes Using Iterative Bit-Channel Upgrading
Venue: arXiv cs.IT 2013
Year: 2013

The definition of polar codes given by Arikan is explicit, but the construction complexity is an issue. This is due to the exponential growth in the size of the output alphabet of the bit-channels as the codeword length increases. Tal and Vardy recently presented a method for constructing polar codes which controls this growth. They approximated each bit-channel with a better channel and a worse channel while reducing the alphabet size. They constructed a polar code based on the worse channel and used the better channel to measure the distance from the optimal channel. This paper considers the knowledge gained from the perspective of the better channel. A method is presented using iterative upgrading of the bit-channels which successively results in a channel closer to the original one. It is shown that this approach can be used to obtain a channel arbitrarily close to the original channel, and therefore to the optimal construction of a polar code.
q-ary Compressive Sensing
Venue: arXiv cs.IT 2013
Year: 2013

We introduce q-ary compressive sensing, an extension of 1-bit compressive sensing. We propose a novel sensing mechanism and a corresponding recovery procedure. The recovery properties of the proposed approach are analyzed both theoretically and empirically. Results in 1-bit compressive sensing are recovered as a special case. Our theoretical results suggest a tradeoff between the quantization parameter q, and the number of measurements m in the control of the error of the resulting recovery algorithm, as well its robustness to noise.
Basic Classes of Grammars with Prohibition
Venue: arXiv cs.FL 2013
Year: 2013

A practical tool for natural language modeling and development of human-machine interaction is developed in the context of formal grammars and languages. A new type of formal grammars, called grammars with prohibition, is introduced. Grammars with prohibition provide more powerful tools for natural language generation and better describe processes of language learning than the conventional formal grammars. Here we study relations between languages generated by different grammars with prohibition based on conventional types of formal grammars such as context-free or context sensitive grammars. Besides, we compare languages generated by different grammars with prohibition and languages generated by conventional formal grammars. In particular, it is demonstrated that they have essentially higher computational power and expressive possibilities in comparison with the conventional formal grammars. Thus, while conventional formal grammars are recursive and subrecursive algorithms, many classes of grammars with prohibition are superrecursive algorithms. Results presented in this work are aimed at the development of human-machine interaction, modeling natural languages, empowerment of programming languages, computer simulation, better software systems, and theory of recursion.
Object Detection in Real Images
Venue: arXiv cs.CV 2013
Year: 2013

Object detection and recognition are important problems in computer vision. Since these problems are meta-heuristic, despite a lot of research, practically usable, intelligent, real-time, and dynamic object detection/recognition methods are still unavailable. We propose a new object detection/recognition method, which improves over the existing methods in every stage of the object detection/recognition process. In addition to the usual features, we propose to use geometric shapes, like linear cues, ellipses and quadrangles, as additional features. The full potential of geometric cues is exploited by using them to extract other features in a robust, computationally efficient, and less meta-heuristic manner. We also propose a new hierarchical codebook, which provides good generalization and discriminative properties. The codebook enables fast multi-path inference mechanisms based on propagation of conditional likelihoods, that make it robust to occlusion and noise. It has the capability of dynamic learning. We also propose a new learning method that has generative and discriminative learning capabilities, does not need large and fully supervised training dataset, and is capable of online learning. The preliminary work of detecting geometric shapes in real images has been completed. This preliminary work is the focus of this report. Future path for realizing the proposed object detection/recognition method is also discussed in brief.
Strategic Advantage in Web Tourism Promotion: An e-Commerce Strategy for Developing Countries
Venue: arXiv cs.CY 2013
Year: 2013

This research informs the means to develop an e-commerce strategy for web based tourism promotion of hotels located in developing countries. The study explored the aspects related to the use of information systems in web based tourism promotion, along with a focus on the organizational factors affecting the use of e-commerce strategy. Interviews were conducted with the managers of selected five sample hotels located in Sri Lanka. A structured web content analysis was undertaken for all five sample hotels to trace process level data on the e-commerce web content. Specific aspects of web content analysis include interactivity, trust, information and value adding features. Instrument for web content analysis was developed by the researcher. The outcome of research produces an outline for developing an e-commerce strategy for hotels located in developing countries to achieve strategic advantages in web based tourism promotion.
The Jordan-Brouwer theorem for the digital normal n-space Zn
Venue: arXiv cs.DM 2013
Year: 2013

In this paper we investigate properties of digital spaces which are represented by graphs. We find conditions for digital spaces to be digital n-manifolds and n-spheres. We study properties of partitions of digital spaces and prove a digital analog of the Jordan-Brouwer theorem for the normal digital n-space Zn.
Intra-Domain Pathlet Routing
Venue: arXiv cs.NI 2013
Year: 2013

Internal routing inside an ISP network is the foundation for lots of services that generate revenue from the ISP's customers. A fine-grained control of paths taken by network traffic once it enters the ISP's network is therefore a crucial means to achieve a top-quality offer and, equally important, to enforce SLAs. Many widespread network technologies and approaches (most notably, MPLS) offer limited (e.g., with RSVP-TE), tricky (e.g., with OSPF metrics), or no control on internal routing paths. On the other hand, recent advances in the research community are a good starting point to address this shortcoming, but miss elements that would enable their applicability in an ISP's network. We extend pathlet routing by introducing a new control plane for internal routing that has the following qualities: it is designed to operate in the internal network of an ISP; it enables fine-grained management of network paths with suitable configuration primitives; it is scalable because routing changes are only propagated to the network portion that is affected by the changes; it supports independent configuration of specific network portions without the need to know the configuration of the whole network; it is robust thanks to the adoption of multipath routing; it supports the enforcement of QoS levels; it is independent of the specific data plane used in the ISP's network; it can be incrementally deployed and it can nicely coexist with other control planes. Besides formally introducing the algorithms and messages of our control plane, we propose an experimental validation in the simulation framework OMNeT++ that we use to assess the effectiveness and scalability of our approach.
An Ontology Construction Approach for the Domain Of Poultry Science Using Protege
Venue: arXiv cs.AI 2013
Year: 2013

The information retrieval systems that are present nowadays are mainly based on full text matching of keywords or topic based classification. This matching of keywords often returns a large number of irrelevant information and this does not meet the users query requirement. In order to solve this problem and to enhance the search using semantic environment, a technique named ontology is implemented for the field of poultry in this paper. Ontology is an emerging technique in the current field of research in semantic environment. This paper constructs ontology using the tool named Protege version 4.0 and this also generates Resource Description Framework schema and XML scripts for using poultry ontology in web.
Thrifty Algorithms for Multistage Robust Optimization
Venue: arXiv cs.DS 2013
Year: 2013

We consider a class of multi-stage robust covering problems, where additional information is revealed about the problem instance in each stage, but the cost of taking actions increases. The dilemma for the decision-maker is whether to wait for additional information and risk the inflation, or to take early actions to hedge against rising costs. We study the "k-robust" uncertainty model: in each stage i = 0, 1,...,T, the algorithm is shown some subset of size k_i that completely contains the eventual demands to be covered; here k_1 > k_2 >...> k_T which ensures increasing information over time. The goal is to minimize the cost incurred in the worst-case possible sequence of revelations. For the multistage k-robust set cover problem, we give an O(log m + log n)-approximation algorithm, nearly matching the Ω(log n + log m/loglog m) hardness of approximation even for T=2 stages. Moreover, our algorithm has a useful "thrifty" property: it takes actions on just two stages. We show similar thrifty algorithms for multi-stage k-robust Steiner tree, Steiner forest, and minimum-cut. For these problems our approximation guarantees are O(min{T, log n, log L_{max}), where L_{max} is the maximum inflation over all the stages. We conjecture that these problems also admit O(1)-approximate thrifty algorithms.
Computer Interaction and the Benefits of Social Networking for People with Borderline Personality Disorder: Enlightening Mental Health Professionals
Venue: arXiv cs.HC 2013
Year: 2013

This paper seeks to present the findings of a focus group and questionnaire in assessing how aware mental health professionals, who have experience with people with Borderline Personality Disorder (BPD), are in the extent of ICT based support for people with BPD. The methods used were both qualitative and quantitative and used descriptive data. Content analysis was used to explore specific themes and results were cross-examined between the two methods. The work should be viewed as an exploratory study into the viability and likely acceptance of a virtual support community specifically designed for people with BPD. The long term aim is to provide additional support for people with BPD, especially when they are in crisis and might be at a higher risk of harm.
Looking back at Facebook content and the positive impact upon wellbeing: Exploring reminiscing as a tool for self soothing
Venue: arXiv cs.CY 2013
Year: 2013

The premise of this paper is to explore the potential of reminiscing in facilitating self soothing. The research presented looks at people's activities on Facebook and whether these particular activities impact upon their perceived sense of wellbeing, furthermore, whether specific Facebook activities enable a self-soothing effect when feeling low in mood. A survey was distributed amongst Facebook users. The results from the study appear to indicate that in comparison to other Facebook activities, looking back upon photos and wall posts in particular, could have a positive impact upon wellbeing. Additionally, the results indicate that people who have mental health problems, experience a more positive impact upon their wellbeing when looking at photos and wall posts, than those who did not have a history of mental health issues. The results from the research presented here contribute towards the viability of developing a mobile application to facilitate positive reminiscing
LFTL: A multi-threaded FTL for a Parallel IO Flash Card under Linux
Venue: arXiv cs.OS 2013
Year: 2013

New PCI-e flash cards and SSDs supporting over 100,000 IOPs are now available, with several usecases in the design of a high performance storage system. By using an array of flash chips, arranged in multiple banks, large capacities are achieved. Such multi-banked architecture allow parallel read, write and erase operations. In a raw PCI-e flash card, such parallelism is directly available to the software layer. In addition, the devices have restrictions such as, pages within a block can only be written sequentially. The devices also have larger minimum write sizes (greater than 4KB). Current flash translation layers (FTLs) in Linux are not well suited for such devices due to the high device speeds, architectural restrictions as well as other factors such as high lock contention. We present a FTL for Linux that takes into account the hardware restrictions, that also exploits the parallelism to achieve high speeds. We also consider leveraging the parallelism for garbage collection by scheduling the garbage collection activities on idle banks. We propose and evaluate an adaptive method to vary the amount of garbage collection according to the current I/O load on the device.
Perangkat lunak bantu mengenal huruf arab melayu ke bentuk huruf latin bahasa Indonesia
Venue: arXiv cs.OH 2013
Year: 2013

The development of computer science has contributed greatly for increasing of efficiency and effectively. Many areas are covered by computer science, included education. The purpose of this research is to introduce jawi a type of Indonesian letters. Jawis letter is one of the most popular letter in the past. But right now few people can read and understand it. Many documents in the past was written in Jawi. The writer develop or build the software using Pressman method, and tools such as Microsoft Visual Basic, and Microsoft Access. This software can introduce Jawi then people can learn it easily.
On Graph Deltas for Historical Queries
Venue: arXiv cs.DB 2013
Year: 2013

In this paper, we address the problem of evaluating historical queries on graphs. To this end, we investigate the use of graph deltas, i.e., a log of time-annotated graph operations. Our storage model maintains the current graph snapshot and the delta. We reconstruct past snapshots by applying appropriate parts of the graph delta on the current snapshot. Query evaluation proceeds on the reconstructed snapshots but we also propose algorithms based mostly on deltas for efficiency. We introduce various techniques for improving performance, including materializing intermediate snapshots, partial reconstruction and indexing deltas.
PENCIL: Towards a Platform-Neutral Compute Intermediate Language for DSLs
Venue: arXiv cs.PL 2013
Year: 2013

We motivate the design and implementation of a platform-neutral compute intermediate language (PENCIL) for productive and performance-portable accelerator programming.
A realistic distributed storage system: the rack model
Venue: arXiv cs.IT 2013
Year: 2013

In a realistic distributed storage environment, storage nodes are usually placed in racks, a metallic support designed to accommodate electronic equipment. It is known that the communication (bandwidth) cost between nodes which are in the same rack is much lower than between nodes which are in different racks. In this paper, a new model, where the storage nodes are placed in two racks, is proposed and analyzed. Moreover, the two-rack model is generalized to any number of racks. In this model, the storage nodes have different repair costs depending on the rack where they are placed. A threshold function, which minimizes the amount of stored data per node and the bandwidth needed to regenerate a failed node, is shown. This threshold function generalizes the ones given for previous distributed storage models. The tradeoff curve obtained from this threshold function is compared with the ones obtained from the previous models, and it is shown that this new model outperforms the previous ones in terms of repair cost.
Low Latency Communications
Venue: arXiv cs.IT 2013
Year: 2013

Numerous applications demand communication schemes that minimize the transmission delay while achieving a given level of reliability. An extreme case is high-frequency trading whereby saving a fraction of millisecond over a route between Chicago and New York can be a game-changer. While such communications are often carried by fiber, microwave links can reduce transmission delays over large distances due to more direct routes and faster wave propagation. In order to bridge large distances, information is sent over a multihop relay network. Motivated by these applications, this papers present an information-theoretic approach to the design of optimal multihop microwave networks that minimizes end-to-end transmission delay. To characterize the delay introduced by coding, we derive error exponents achievable in multihop networks. We formulate and solve an optimization problem that determines optimal selection of amplify-and-forward and decode-and-forward relays. We present the optimal solution for several examples of networks. We prove that in high SNR the optimum transmission scheme is for all relays to perform amplify-and-forward. We then analyze the impact of deploying noisy feedback
Characterization of Minimum Cycle Basis in Weighted Partial 2-trees
Venue: arXiv cs.DM 2013
Year: 2013

For a weighted outerplanar graph, the set of lex short cycles is known to be a minimum cycle basis [Inf. Process. Lett. 110 (2010) 970-974 ]. In this work, we show that the set of lex short cycles is a minimum cycle basis in weighted partial 2-trees (graphs of treewidth two) which is a superclass of outerplanar graphs.
Polar Lattices: Where Arıkan Meets Forney
Venue: arXiv cs.IT 2013
Year: 2013

In this paper, we propose the explicit construction of a new class of lattices based on polar codes, which are provably good for the additive white Gaussian noise (AWGN) channel. We follow the multilevel construction of Forney \textit{et al.} (i.e., Construction D), where the code on each level is a capacity-achieving polar code for that level. The proposed polar lattices are efficiently decodable by using multistage decoding. Computable performance bounds are derived to measure the gap to the generalized capacity at given error probability. A design example is presented to demonstrate the performance of polar lattices.
Queue-Based Random-Access Algorithms: Fluid Limits and Stability Issues
Venue: arXiv cs.NI 2013
Year: 2013

We use fluid limits to explore the (in)stability properties of wireless networks with queue-based random-access algorithms. Queue-based random-access schemes are simple and inherently distributed in nature, yet provide the capability to match the optimal throughput performance of centralized scheduling mechanisms in a wide range of scenarios. Unfortunately, the type of activation rules for which throughput optimality has been established, may result in excessive queue lengths and delays. The use of more aggressive/persistent access schemes can improve the delay performance, but does not offer any universal maximum-stability guarantees. In order to gain qualitative insight and investigate the (in)stability properties of more aggressive/persistent activation rules, we examine fluid limits where the dynamics are scaled in space and time. In some situations, the fluid limits have smooth deterministic features and maximum stability is maintained, while in other scenarios they exhibit random oscillatory characteristics, giving rise to major technical challenges. In the latter regime, more aggressive access schemes continue to provide maximum stability in some networks, but may cause instability in others. Simulation experiments are conducted to illustrate and validate the analytical results.
Multi-Feedback Successive Interference Cancellation for Multiuser MIMO Systems
Venue: arXiv cs.IT 2013
Year: 2013

In this paper, a low-complexity multiple feedback successive interference cancellation (MF-SIC) strategy is proposed for the uplink of multiuser multiple-input multiple-output (MU-MIMO) systems. In the proposed MF-SIC {algorithm with shadow area constraints (SAC)}, an enhanced interference cancellation is achieved by introducing {constellation points as the candidates} to combat the error propagation in decision feedback loops. We also combine the MF-SIC with multi-branch (MB) processing, which achieves a higher detection diversity order. For coded systems, a low-complexity soft-input soft-output (SISO) iterative (turbo) detector is proposed based on the MF and the MB-MF interference suppression techniques. The computational complexity of the MF-SIC is {comparable to} the conventional SIC algorithm {since very little additional complexity is required}. {Simulation} results show that the algorithms significantly outperform the conventional SIC scheme and {approach} the optimal detector.
Low-Complexity Algorithm for Worst-Case Utility Maximization in Multiuser MISO Downlink
Venue: arXiv cs.IT 2013
Year: 2013

This work considers worst-case utility maximization (WCUM) problem for a downlink wireless system where a multiantenna base station communicates with multiple single-antenna users. Specifically, we jointly design transmit covariance matrices for each user to robustly maximize the worst-case (i.e., minimum) system utility function under channel estimation errors bounded within a spherical region. This problem has been shown to be NP-hard, and so any algorithms for finding the optimal solution may suffer from prohibitively high complexity. In view of this, we seek an efficient and more accurate suboptimal solution for the WCUM problem. A low-complexity iterative WCUM algorithm is proposed for this nonconvex problem by solving two convex problems alternatively. We also show the convergence of the proposed algorithm, and prove its Pareto optimality to the WCUM problem. Some simulation results are presented to demonstrate its substantial performance gain and higher computational efficiency over existing algorithms.