ppxscal/embedding_network huggingface dataset:
New Features of Latin Dances: Analysis of Salsa, ChaCha, and Rumba
Authors: Jean-Philippe Aumasson, Simon Fischer, Shahram Khazaei, Willi Meier, Christian Rechberger
Venue: Fast Software Encryption: 15th International Workshop, FSE 2008, Lausanne, Switzerland, February 10-13, 2008, Revised Selected Papers (2008)

The stream cipher Salsa20 was introduced by Bernstein in 2005 as a candidate in the eSTREAM project, accompanied by the reduced versions Salsa20/8 and Salsa20/12. ChaCha is a variant of Salsa20 aiming at bringing better diffusion for similar performance. Variants of Salsa20 with up to 7 rounds (instead of 20) have been broken by differential cryptanalysis, while ChaCha has not been analyzed yet. We introduce a novel method for differential cryptanalysis of Salsa20 and ChaCha, inspired by correlation attacks and related to the notion of neutral bits. This is the first application of neutral bits in stream cipher cryptanalysis. It allows us to break the 256-bit version of Salsa20/8, to bring faster attacks on the 7-round variant, and to break 6- and 7-round ChaCha. In a second part, we analyze the compression function Rumba, built as the XOR of four Salsa20 instances and returning a 512-bit output. We find collision and preimage attacks for two simplified variants, then we discuss differential attacks on the original version, and exploit a high-probability differential to reduce complexity of collision search from 2256 to 279 for 3-round Rumba. To prove the correctness of our approach we provide examples of collisions and near-collisions on simplified versions.
Exploiting Unique Fixed Points
Authors: Ralf Hinze
Venue: Proceedings of the 9th international conference on Mathematics of Program Construction (2008)

Functional programmers happily use equational reasoning and induction to prove properties of recursive programs. To show properties of corecursive programs they employ coinduction, per perhaps less enthusiastically. Coinduction is often considered as a rather low-level proof method, especially, as it seems to depart rather radically from equational reasoning. In this talk we introduce an alternative proof technique based on unique fixed points. To make the idea concrete, consider the simplest example of a coinductive type: the type of streams, where a stream is an infinite sequence of elements. In a lazy functional language, such as Haskell, streams are easy to define and many textbooks on Haskell reproduce the folklore examples of Fibonacci or Hamming numbers defined by recursion equations over streams. One has to be a bit careful in formulating a recursion equation basically avoiding that the sequence defined swallows its own tail. However, if this care is exercised, the equation even possesses a unique solution, a fact that is not very widely appreciated. Uniqueness can be exploited to prove that two streams are equal: if they satisfy the same recursion equation, then they are! We will use this proof technique to infer some intriguing facts about particular streams and to develop the basics of finite calculus. Quite attractively, the resulting proofs have a strong equational flavour. In a nutshell, the proof method brings equational reasoning to the coworld. Of course, it is by no means restricted to streams and can be used equally well to prove properties of infinite trees or the observational equivalence of instances of an abstract datatype.
Derivation Tree Analysis for Accelerated Fixed-Point Computation
Authors: Javier Esparza, Stefan Kiefer, Michael Luttenberger
Venue: Proceedings of the 12th international conference on Developments in Language Theory (2008)

We show that for several classes of idempotent semirings the least fixed-point of a polynomial system of equations is equal to the least fixed-point of a linear system obtained by "linearizing" the polynomials of in a certain way. Our proofs rely on derivation tree analysis, a proof principle that combines methods from algebra, calculus, and formal language theory, and was first used in [5] to show that Newton's method over commutative and idempotent semirings converges in a linear number of steps. Our results lead to efficient generic algorithms for computing the least fixed-point. We use these algorithms to derive several consequences, including an O(N 3) algorithm for computing the throughput of a context-free grammar (obtained by speeding up the O(N 4) algorithm of [2]), and a generalization of Courcelle's result stating that the downward-closed image of a context-free language is regular [3].
An Extensible Virtual Digital Libraries Generator
Authors: Massimiliano Assante, Leonardo Candela, Donatella Castelli, Luca Frosini, Lucio Lelii, Paolo Manghi, Andrea Manzi, Pasquale Pagano, Manuele Simi
Venue: Proceedings of the 12th European conference on Research and Advanced Technology for Digital Libraries (2008)

In this paper we describe the design and implementation of the VDL Generator, a tool to simplify and automatise the Digital Library development process. In particular, we discuss how our approach to the realisation of this tool simplifies the task of implementing, extending and modifying such a fundamental component. This tool models its issue as a generic search problem that can easily be adapted to different application scenarios. In particular, to guarantee its extensibility we carefully identify, isolate and organise the VDL Generator constituents, i.e. (i) the set of logical components that can be used when designing a Digital Library, (ii) the set of physical components that by implementing the logical components contribute to implement the Digital Library and (iii) the search strategy exploited to accomplish the generation task. Furthermore, we report on the experiences matured in implementing and exploiting such an innovative service in the context of the Diligent EU funded project and discuss future plans for its consolidation.
The Rabbit Stream Cipher
Authors: Martin Boesgaard, Mette Vesterager, Erik Zenner
Venue: New Stream Cipher Designs: The eSTREAM Finalists (2008)

The stream cipher Rabbit was first presented at FSE 2003 [3], and no attacks against it have been published until now. With a measured encryption/decryption speed of 3.7 clock cycles per byte on a Pentium III processor, Rabbit does also provide very high performance. This paper gives a concise description of the Rabbit design and some of the cryptanalytic results available.
Global Binarization of Document Images Using a Neural Network
Authors: Adnan Khashman, Boran Sekeroglu
Venue: Proceedings of the 2007 Third International IEEE Conference on Signal-Image Technologies and Internet-Based System (2007)

In degraded scanned documents, where considerable background noise or variation in contrast and illumination exists, pixels may not be easily classified as foreground or background pixels. Thus, the need to perform document binarization in order to enhance the document image by separating foregrounds (text) from backgrounds. A new approachthat combines a global thresholding method and a supervised neural network classifier is proposed to enhance scanned documents and to separate foreground and background layers. Thresholding is first applied using Mass-Difference thresholding to obtain various local optimumthreshold values in an image. The neural network is then trained using these values at its input and a single global optimum threshold value for the entire image at its output. Compared with other methods, experimental results show that this combined approach is computationally cost effectiveand is capable of enhancing degraded documents with superior foreground and background separation results.
Transformations and Preservation of Self-assembly Dynamics through Homotheties
Authors: Florent Becker
Venue: Language and Automata Theory and Applications: Second International Conference, LATA 2008, Tarragona, Spain, March 13-19, 2008. Revised Papers (2008)

We introduce a new notion in self-assembly, that of transforming the dynamics of assembly. This notion allows us to have transformation of the plane computed within the assembly process. Then we apply this notion to zooming. The possibility of zooming depends on the order condition. This shows that this condition, which arose from engineering concerns (how to design understandable tile systems) is indeed an important condition of regularity for the assembly process.
A Sketch-Based Interface for Modeling Myocardial Fiber Orientation
Authors: Kenshi Takayama, Takeo Igarashi, Ryo Haraguchi, Kazuo Nakazawa
Venue: Proceedings of the 8th international symposium on Smart Graphics (2007)

This article proposes a sketch-based interface for modeling muscle fiber orientation of a 3D virtual heart model. Our target was electrophysiological simulation of the heart and fiber orientation is one of the key elements to obtaining reliable simulation results. We designed the interface and algorithm based on the observation that fiber orientation is always parallel to the surface of the heart. The user specifies the fiber orientation by drawing a freeform stroke on the object surface. The system first builds a vector field on the surface by applying Laplacian smoothing to the mesh vertices and then builds a volumetric vector field by applying Laplacian smoothing to the voxels. We demonstrate the usefulness of the proposed method through a user study with a cardiologist.
A collaborative and experiential learning model powered by real-world projects
Authors: Mihaela Sabin
Venue: Proceedings of the 9th ACM SIGITE conference on Information technology education (2008)

Information Technology (IT) curricula's strong application component and its focus on user centeredness and team work require that students experience directly real-world projects for real users of IT solutions. Although the merit of this IT educational tenet is universally recognized, delivering collaborative and experiential learning has its challenges. Reaching out to identify projects formulated by actual organizations adds significantly to course preparation. There is a certain level of risk involved with delivering a useful solution while, at the same time, enough room should be allowed for students to experiment with, be wrong about, review, and learn. Challenges pertaining to the real-world aspect of problem-based learning are compounded by managing student teams and assessing their work such that both individual and collective contributions are taken into account. Finally, the quality of the project releases is not the only measure of student learning. Students should be given meaningful opportunities to practice, improve, and demonstrate their communication and interpersonal skills. In this paper we present our experience with two courses in which teams of students worked on real-world projects involving three external partners. We describe how each of the challenges listed above has impacted the course requirements, class instruction, team dynamics, assessment, and learning in these courses. Course assessment and survey data from students are linked to learning outcomes and point to areas where the collaborative and experiential learning model needs improvement.
Mobile Sink Routing Protocol with Registering in Cluster-Based Wireless Sensor Networks
Authors: Ying-Hong Wang, Kuo-Feng Huang, Ping-Fang Fu, Jun-Xuan Wang
Venue: Proceedings of the 5th international conference on Ubiquitous Intelligence and Computing (2008)

Wireless Sensor Networks (WSNs) are wireless networks consisting of sink nodes and multiple sensor nodes. While the wireless sensor nodes have several advantages, such as the compact size and the low cost, corresponding constraints on resources can result. The greatest challenge among all is the constraint on energy. Therefore, how to minimize the energy consumption while maintaining an extended network lifetime becomes the most critical issue when it comes to the design of the routing protocol for the wireless sensor networks.
SCA-Based Reconfigurable Access Terminal
Authors: Junsik Kim, Sangchul Oh, Eunseon Cho, Namhoon Park, Nam Kim
Venue: Proceedings of the 7th international conference on Computational Science, Part IV: ICCS 2007 (2007)

In this paper, we propose a Reconfigurable Access Terminal (RAT) which is composed of SDR(Software Defined Radio) hardware platform test bed and SCA(Software Communication Architecture) - based software platform. Specifically, we propose a design of the SDR Access Terminal middleware, wireless protocol software component and the procedure of reconfiguration which changes one mode into the other mode. Our RAT system shows that it is capable of changing mode between WiMAX(World Interoperability for Microwave Access) and HSDPA(High Speed Downlink Packet Access). The radio access protocol and application components of RAT are designed through a SCA adapter.
Efficient evaluation functions for evolving coordination
Authors: A. Agogino, K. Tumer
Venue: Evolutionary Computation (2008)

This paper presents fitness evaluation functions that efficiently evolve coordination in large multi-component systems. In particular, we focus on evolving distributed control policies that are applicable to dynamic and stochastic environments. While it is appealing to evolve such policies directly for an entire system, the search space is prohibitively large in most cases to allow such an approach to provide satisfactory results. Instead, we present an approach based on evolving system components individually where each component aims to maximize its own fitness function. Though this approach sidesteps the exploding state space concern, it introduces two new issues: (1) how to create component evaluation functions that are aligned with the global evaluation function; and (2) how to create component evaluation functions that are sensitive to the fitness changes of that component, while remaining relatively insensitive to the fitness changes of other components in the system. If the first issue is not addressed, the resulting system becomes uncoordinated; if the second issue is not addressed, the evolutionary process becomes either slow to converge or worse, incapable of converging to good solutions. This paper shows how to construct evaluation functions that promote coordination by satisfying these two properties. We apply these evaluation functions to the distributed control problem of coordinating multiple rovers to maximize aggregate information collected. We focus on environments that are highly dynamic (changing points of interest), noisy (sensor and actuator faults), and communication limited (both for observation of other rovers and points of interest) forcing the rovers to evolve generalized solutions. On this difficult coordination problem, the control policy evolved using aligned and component-sensitive evaluation functions outperforms global evaluation functions by up to 400%. More notably, the performance improvements increase when the problems become more difficult (larger, noisier, less communication). In addition we provide an analysis of the results by quantifying the two characteristics (alignment and sensitivity discussed above) leading to a systematic study of the presented fitness functions.
An alternative information web for visually impaired users in developing countries
Authors: Nitendra Rajput, Sheetal Agarwal, Arun Kumar, Amit Anil Nanavati
Venue: Proceedings of the 10th international ACM SIGACCESS conference on Computers and accessibility (2008)

Websites in World Wide Web are primarily meant for visual consumption. Moreover, the wide variety of visual controls available make it harder to interpret the websites with screen readers. This problem of accessing information and services on the web escalates even further for visually impaired in developing regions since most are either semi-literate/illiterate or cannot afford computers and high-end phones with screen reading capability. In this paper, we present an alternate platform -- the World Wide Telecom Web (WWTW). WWTW is already being successfully deployed as a network of VoiceSites that can be created and accessed by a voice interaction over an ordinary phone. WWTW presents a whole new set of opportunities for delivering information and services to the visually impaired. We present a preliminary user study that leads us towards the belief that the Telecom Web can be the mainstream Web for blind users.
The Necessity of Combining ELN and SACK to Improve TCP Performance over Heterogeneous Networks
Authors: Yaogong Wang, Li Pan, Jianhua Li
Venue: Proceedings of the 2007 Third International IEEE Conference on Signal-Image Technologies and Internet-Based System (2007)

TCP suffers severe performance degradation over heterogeneous networks due to its inadaptability to the characteristics of the wireless link. Techniques such as Explicit Loss Notification (ELN) and Selective Acknowledgement (SACK) have been proposed to mitigate such link-related degradations. In this paper, we demonstrate the inadequacy of using ELN or SACK alone and the necessity of combining them. It will be shown that the combination of ELN and SACK is not a simple superposition of two mechanisms, but rather is an organic integration with positive interactions on each other. Simulation results show that, by combining ELN and SACK, TCP achieves considerably higher throughput than using any one mechanism separately.
Approximating power indices
Authors: Yoram Bachrach, Evangelos Markakis, Ariel D. Procaccia, Jeffrey S. Rosenschein, Amin Saberi
Venue: Proceedings of the 7th international joint conference on Autonomous agents and multiagent systems - Volume 2 (2008)

Many multiagent domains where cooperation among agents is crucial to achieving a common goal can be modeled as coalitional games. However, in many of these domains, agents are unequal in their power to affect the outcome of the game. Prior research on weighted voting games has explored power indices, which reflect how much "real power" a voter has. Although primarily used for voting games, these indices can be applied to any simple coalitional game. Computing these indices is known to be computationally hard in various domains, so one must sometimes resort to approximate methods for calculating them. We suggest and analyze randomized methods to approximate power indices such as the Banzhaf power index and the Shapley-Shubik power index. Our approximation algorithms do not depend on a specific representation of the game, so they can be used in any simple coalitional game. Our methods are based on testing the game's value for several sample coalitions. We also show that no approximation algorithm can do much better for general coalitional games, by providing lower bounds for both deterministic and randomized algorithms for calculating power indices.
An Effective Defense against Intrusive Web Advertising
Authors: Viktor Krammer
Venue: Proceedings of the 2008 Sixth Annual Conference on Privacy, Security and Trust (2008)

Intrusive Web advertising such as pop-ups and animated layer ads, which distract the user from reading or navigating through the main content of Web pages, is being perceived as annoying by an increasing number of users. As a response to the growing amount of extraneous content on today's Web and due to the lack of regulations imposed on abusive advertisers the author discusses the pros and cons of ad blocking, explores the different types of Web advertisements currently available and presents Quero, a novel Web browser-based content filter which implements a rule-based classifier that exploits, for example, hints present in the URL in order to classify objects as ads. Additionally, the author conducts a Web study to characterize online ads and measure the effectiveness of his solution against a manual classification. As a result, it is shown that a surprisingly small number of rules is sufficient to block almost all ads on the Web.
Info-fuzzy algorithms for mining dynamic data streams
Authors: Lior Cohen, Gil Avrahami, Mark Last, Abraham Kandel
Venue: Applied Soft Computing (2008)

Most data-mining algorithms assume static behavior of the incoming data. In the real world, the situation is different and most continuously collected data streams are generated by dynamic processes, which may change over time, in some cases even drastically. The change in the underlying concept, also known as concept drift, causes the data-mining model generated from past examples to become less accurate and relevant for classifying the current data. Most online learning algorithms deal with concept drift by generating a new model every time a concept drift is detected. On one hand, this solution ensures accurate and relevant models at all times, thus implying an increase in the classification accuracy. On the other hand, this approach suffers from a major drawback, which is the high computational cost of generating new models. The problem is getting worse when a concept drift is detected more frequently and, hence, a compromise in terms of computational effort and accuracy is needed. This work describes a series of incremental algorithms that are shown empirically to produce more accurate classification models than the batch algorithms in the presence of a concept drift while being computationally cheaper than existing incremental methods. The proposed incremental algorithms are based on an advanced decision-tree learning methodology called ''Info-Fuzzy Network'' (IFN), which is capable to induce compact and accurate classification models. The algorithms are evaluated on real-world streams of traffic and intrusion-detection data.
Universal active current filter using single operational transconductance amplifier
Authors: Chun-Ming Chang, Ching-Han Chen, Shu-Hui Tu, Chun-Li Hou, Jiun-Wei Horng
Venue: Proceedings of the 7th WSEAS International Conference on Applied Computer and Applied Computational Science (2008)

The realization of the second-order universal (low-pass, band-pass, high-pass, band-reject, and all-pass) active current filter using a single operational transconductance amplifier (OTA), two grounded capacitors, and one resistosr is proposed in this paper. Three input signals and the tunable tranconductance of the OTA determine the five generic filtering output signals. H-Spice simulations with 0.35µm process are used to validate the theoretical predictions of the filtering output signals, and show the low sensitivitie, and the sensitivity frequency responses.
Compiling GOAL Agent Programs into Jazzyk Behavioural State Machines
Authors: Koen Hindriks, Peter Novák
Venue: Proceedings of the 6th German conference on Multiagent System Technologies (2008)

A variety of agent-oriented programming languages based on concepts such as beliefs and goals has been proposed in the literature. Even though most of these languages now come with interpreters implemented in e.g. Java and can be used to write software agents, there is little work reporting how to implement such languages or to identify a core instruction set that would facilitate such implementation. In this paper we introduce a compiler for the language GOAL into the framework of Jazzyk Behavioural State Machines. The result is a translation of key agent concepts such as beliefs and goals into Jazzyk which lacks these notions, thus providing some evidence that it may provide a sufficient instruction set for implementing agent programs. Moreover, arguably, the implementation strategy used can be applied also to other agent programming languages.