ppxscal/embedding_network huggingface dataset:
Data Preparation for User Profiling from Traffic Log
Authors: Marek Kumpost
Venue: Proceedings of the The International Conference on Emerging Security Information, Systems, and Technologies (2007)

This paper presents our current work on traffic log processing. Our goal is to find an approach to modeling user behaviour based on their behavioural patterns. Since the amount of input data we have is really large, effective preprocessing is crucial for the profiling to provide significant results. This paper presents our approach to restricting the input data with respect to its relevance. We use histogram clustering to identify sets of users with similar frequencies of communication; entropy and TF-IDF (Term FrequencyInverse Document Frequency) help to select destinations that are relevant for a given set of users. The main profiling is done with preprocessed data and our experiments show that this approach to restricting the input has a positive impact on the significance of results.
A segment-based hidden markov model for real-setting pinyin-to-chinese conversion
Authors: Xiaohua Zhou, Xiaohua Hu, Xiaodan Zhang, Xiajiong Shen
Venue: Proceedings of the sixteenth ACM conference on Conference on information and knowledge management (2007)

Hidden markov model (HMM) is frequently used for Pinyin-to-Chinese conversion. But it only captures the dependency with the preceding character. Higher order markov models can bring higher accuracy, but are computationally unaffordable to average PC settings. We propose a segment-based hidden markov model (SHMM), which has the same magnitude of complexity as first-order HMM, but generates higher decoding accuracy. SHMM tells a word from a bigram connecting two words, and assigns a reasonable probability to words as a whole. It is more powerful than HMM to decode words containing over two characters. We conduct a comprehensive Pinyin-to-Chinese conversion evaluation on Lancaster corpus. The experiment shows the perfect sentence accuracy is improved from 34.7% (HMM) to 43.3% (SHMM). The one-error sentence accuracy is increased from 72.7% to 78.3%. Furthermore, SHMM can seamlessly integrate with pinyin typing correction, acronym pinyin input, user-defined words, and self-adaptive learning all of which are a must for a commercial Pinyin-to-Chinese conversion product in order to improve the efficiency of pinyin input.
Metal direct nanoimprinting for photonics
Authors: Stefano Buzzi, Franck Robin, Victor Callegari, Jörg F. Löffler
Venue: Microelectronic Engineering (2008)

In this paper metal direct nanoimprinting (embossing) for the production of metallic microparts is discussed, with a main focus on its suitability for the fabrication of metal-containing optical devices such as photonic crystals, plasmon waveguides or chiral structures. Silver and gold were chosen, since they have the lowest light absorption in the near infrared and visible range. They are also easily formable due to their good ductility, which can be further enhanced by processing at elevated temperature. The mold material, which may form part of the optical device, usually consisted of silicon, but other dielectric materials such as silicon oxide and silicon nitride were also successfully tested. Cylindrical and line-shaped holes with lateral dimensions down to 250nm and aspect ratios of up to 5 were etched in silicon wafers. All the structures were successfully filled with silver and gold, and the filling of smaller dimensions is also deemed possible. This technique is therefore suitable for producing metal-containing optical devices working in the infrared, at least down to the standard telecom wavelength of 1.5@mm, which requires metallic dimensions of 200-300nm.
Web-based learning tools: storing usage data makes a difference
Authors: Agathe Merceron, Kalina Yacef
Venue: Proceedings of the sixth conference on IASTED International Conference Web-Based Education - Volume 2 (2007)

Web-based learning tools are often introduced in addition to face-to-face teaching as an extra resource for students to train themselves outside the classroom. How can teachers know whether and how these tools represent an added value for students? In this paper we argue that usage data stored by such tools help teachers to get insight on the learning impact of those tools and that this must be taken into account at the design phase. This is illustrated with two web-based tools Logic-ITA and JFLAP.
On the determination of nontrivial equilibrium configurations close to a bifurcation point
Authors: Gaetano Napoli, Stefano Turzi
Venue: Computers Mathematics with Applications (2008)

Bifurcation phenomena of equilibrium states occur in both standard and complex materials. In this paper we study the equilibrium configurations close to a bifurcation point. In particular the attention is focused on bifurcations of pitchfork type [S.H. Strogatz, Non Linear Dynamics and Chaos, Addison-Wesley Publishing Company, 1994]. This problem is usually solved by using the Signorini's compatibility of the solution expansion in a neighborhood of the critical point. We show how the same results can be reached in another way which involves just the linear term of the solution expansion. As a test, we analyze two bifurcation phenomena: the buckling of an elastic beam under an axial load and the magnetic field-induced optical switch in nematic liquid crystals.
OMR: An Opportunistic Multi-Path Reliable Routing Protocol in Wireless Sensor Networks
Authors: Junzhao Du, Hui Liu, Ping Chen
Venue: Proceedings of the 2007 International Conference on Parallel Processing Workshops (2007)

Motivated by realistic sensor network scenarios that have fading environment and opportunistic transmission, we propose a novel routing protocol, OMR, which integrates routing and MAC protocols to improve the packet delivery ratio, reduce the packet delivery latency, and decrease the energy consumption in multi-hop wireless sensor networks. OMR chooses a packet's route at each hop after the transmission to that hop and the choice is based on the fact that intermediate nodes actually receive the packet and can forward the packet to any nodes at the next hop with high probability. The nodes coordinate to guarantee hop-based reliability while avoiding redundant retransmission by blindly flooding. The timeout and sink initiated retransmission mechanisms by intermediate nodes in OMR guarantee the end-to-end reliability. Piggyback acknowledgement shares the packet and acknowledgement information among neighbors to mitigate the effects of lossy and asymmetric links. The results of intensive simulation using TOSSIM show that OMR performs well compared with traditional routing protocols.
Collective adaptation: The exchange of coding segments
Authors: Thomas Haynes
Venue: Evolutionary Computation (1998)

Coding segments are those subsegments of the chromosome that contribute positively to the fitness evaluation of the chromosome. Clique detection is a NP-complete problem in which we can detect such coding segments. We extract coding segments from chromosomes, and we investigate the duplication of coding segments inside the chromosome and the collection of coding segments outside of the chromosome. We find that duplication of coding segments inside the chromosomes provides a back-up mechanism for the search heuristics. We further find local search in a collective memory of coding segments outside of the chromosome, collective adaptation, enables the search heuristic to represent partial solutions that are larger than realistic chromosomes lengths and to express the solution outside of the chromosome.
Combining environment generation and slicing for modular software model checking
Authors: Oksana Tkachuk, Sreeranga P. Rajan
Venue: Proceedings of the twenty-second IEEE/ACM international conference on Automated software engineering (2007)

To be effective, software model checking needs powerful reduction techniques. In this paper, we present an experimental study that demonstrates effectiveness of environment generation combined with slicing as a model generation and reduction technique. Automatic environments were obtained using the Bandera Environment Generator (BEG) and slicing was performed using the Indus Java slicer. The results show that environment generation implemented in BEG is an aggressive reduction technique. However, it may miss behaviors in the environment and consequently in the module under analysis, making it unsafe. As such, this technique can be effective for detection of errors but not sufficient to prove their absence.Slicing, while a safe technique, may be too approximate and not scalable. Also, slicing implemented in Indus requires a closed system and cannot be safely applied to a module without its environment. In this paper, we show how environment generation and slicing can be combined to detect errors and prove their absence. We applied the combined approach to verify parts of Fujitsu's enterprise software called Interstage Business Process Management (I-BPM)
Fast Computational Algorithms for Bit Reversal
Authors: R. J. Polge
Venue: IEEE Transactions on Computers (1974)

Radix 2 fast Fourier transform programs of the Gentleman-Sande type leave the transformed array in a scrambled order of frequencies. Unscrambling is accomplished by moving each element from its present location into a new location obtained by bit reversal. Bit reversal can be interpreted as an exchange of groups of bits symmetric with respect to a pivot. Two formulas are developed for simultaneous and sequential exchanging in place, with negligible auxiliary storage. Programs for one-step and sequential unscrambling were implemented. Binary unscrambling is useful to unscramble large arrays in peripheral storage. The one-step unscrambling program presented is more efficient than other programs available in the literature.
The Canadian Response to the USA Patriot Act
Authors: David Fraser
Venue: IEEE Security and Privacy (2007)

Since the attacks of September 11, 2001, US authorities have spent untold millions of dollars guarding their frontiers to regulate what gets into the country. On the other side of the border, many Canadian jurisdictions have turned their thoughts to regulating what information flows southward into the US. This isn't out of concern about terrorism but rather about the US response to it.
A Comparative Study of Hierarchical DHT Systems
Authors: Marc Sanchez Artigas, Pedro Garcia Lopez, Antonio F. Skarmeta
Venue: Proceedings of the 32nd IEEE Conference on Local Computer Networks (2007)

Much research in the last few years has been devoted to development of efficient structured peer-to-peer (P2P) overlay networks, which offer distributed hash table (DHT) functionality. Most of these systems have been devised as flat, non-hierarchical structures, in contrast to the most scalable distributed systems of the past. To cope with this, a significant number of hierarchical DHT designs have been proposed in the literature. Unfortunately, no design is "universally" better. Actually, what is lacking is an analytic framework to identify the good hierarchical design for a given workload. In this paper, we provide such a framework, and we use it to compare the two main hierarchical DHT designs: The homogenous design, in which all nodes act equal roles, against the superpeer design, in which a small subset of peers (i.e., the most powerful and stable), behave as proxies, interconnecting clusters with highly dynamic membership. Our analysis reveals that, on the contrary to what was initially expected, the costs incurred by hierarchical superpeer design are not necessarily minimized.
Impulsive Control of T-S Fuzzy Systems
Authors: Xiaohong Zhang, Dong Li, Dan Yang
Venue: Proceedings of the Fourth International Conference on Fuzzy Systems and Knowledge Discovery - Volume 01 (2007)

This paper provides a new viewpoint for fuzzy systems via an impulsive technique, i.e. the impulsive control is introduced into the fuzzy systems based on T-S model and the fuzzy system model with impulsive control is established. The main difference between the proposed control strategy and PDC lies in that the subsystems are the linear impulsive ones and the overall model of the system is the time-varying impulsive control one. Thus, the stability analysis and control design problems of presented system can be reduced to the ones of impulsive control systems. So, the stability issues of the proposed control system are investigated via comparison criterion of differential equations. Finally, the numerical simulations for the chaotic system verify the effectiveness of the proposed design method.
On the ubiquity of certain total type structures
Authors: John Longley
Venue: Mathematical Structures in Computer Science (2007)

It is an empirical observation arising from the study of higher type computability that a wide range of approaches to defining a class of (hereditarily) total functionals over ℕ leads in practice to a relatively small handful of distinct type structures. Among these are the type structure C of KleeneKreisel continuous functionals, its effective substructure Ceff and the type structure HEO of the hereditarily effective operations. However, the proofs of the relevant equivalences are often non-trivial, and it is not immediately clear why these particular type structures should arise so ubiquitously. In this paper we present some new results that go some way towards explaining this phenomenon. Our results show that a large class of extensional collapse constructions always give rise to C, Ceff or HEO (as appropriate). We obtain versions of our results for both the standard and modified extensional collapse constructions. The proofs make essential use of a technique due to Normann. Many new results, as well as some previously known ones, can be obtained as instances of our theorems, but more importantly, the proofs apply uniformly to a whole family of constructions, and provide strong evidence that the three type structures under consideration are highly canonical mathematical objects.
Précis: from unstructured keywords as queries to structured databases as answers
Authors: Alkis Simitsis, Georgia Koutrika, Yannis Ioannidis
Venue: The VLDB Journal &mdash; The International Journal on Very Large Data Bases (2008)

Précis queries represent a novel way of accessing data, which combines ideas and techniques from the fields of databases and information retrieval. They are free-form, keyword-based, queries on top of relational databases that generate entire multi-relation databases, which are logical subsets of the original ones. A logical subset contains not only items directly related to the given query keywords but also items implicitly related to them in various ways, with the purpose of providing to the user much greater insight into the original data. In this paper, we lay the foundations for the concept of logical database subsets that are generated from précis queries under a generalized perspective that removes several restrictions of previous work. In particular, we extend the semantics of précis queries considering that they may contain multiple terms combined through the AND, OR, and NOT operators. On the basis of these extended semantics, we define the concept of a logical database subset, we identify the one that is most relevant to a given query, and we provide algorithms for its generation. Finally, we present an extensive set of experimental results that demonstrate the efficiency and benefits of our approach.
The effect of generalized discriminate analysis (GDA) to the classification of optic nerve disease from VEP signals
Authors: Ayşegül Güven, Kemal Polat, Sadık Kara, Salih Güneş
Venue: Computers in Biology and Medicine (2008)

In this paper, we have investigated the effect of generalized discriminate analysis (GDA) on classification performance of optic nerve disease from visual evoke potentials (VEP) signals. The GDA method has been used as a pre-processing step prior to the classification process of optic nerve disease. The proposed method consists of two parts. First, GDA has been used as pre-processing to increase the distinguishing of optic nerve disease from VEP signals. Second, we have used the C4.5 decision tree classifier, Levenberg Marquart (LM) back propagation algorithm, artificial immune recognition system (AIRS), linear discriminant analysis (LDA), and support vector machine (SVM) classifiers. Without GDA, we have obtained 84.37%, 93.75%, 75%, 76.56%, and 53.125% classification accuracies using C4.5 decision tree classifier, LM back propagation algorithm, AIRS, LDA, and SVM algorithms, respectively. With GDA, 93.75%, 93.86%, 81.25%, 93.75%, and 93.75% classification accuracies have been obtained using the above algorithms, respectively. These results show that the GDA pre-processing method has produced very promising results in diagnosis of optic nerve disease from VEP signals.
A NOR Emulation Strategy over NAND Flash Memory
Authors: Jian-Hong Lin, Yuan-Hao Chang, Jen-Wei Hsieh, Tei-Wei Kuo, Cheng-Chih Yang
Venue: Proceedings of the 13th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications (2007)

This work is motivated by a strong market demand in the replacement of NOR flash memory with NAND flash memory to cut down the cost in many embedded-system designs, such as mobile phones. Different from LRU-related caching or buffering studies, we are interested in prediction-based prefetching based on given execution traces of application executions. An implementation strategy is proposed in the storage of the prefetching information with limited SRAM and run-time overheads. An efficient prediction procedure is presented based on information extracted from application executions to reduce the performance gap between NAND flash memory and NOR flash memory in reads. With the behavior of a target application extracted from a set of collected traces, we show that data access to NOR flash memory can be responded effectively over the proposed implementation.
Strategies for improving the parametric yield and profits of 3D ICs
Authors: Cesare Ferri, Sherief Reda, R. Iris Bahar
Venue: Proceedings of the 2007 IEEE/ACM international conference on Computer-aided design (2007)

Three-Dimensional (3D) Integrated Circuits (ICs) that integrate die with Through-Silicon Vias (TSVs) promise to continue system and functionality scaling beyond the traditional geometric 2D device scaling. 3D integration also improves the performance of ICs by reducing the communication time between different chip components through the use of short TSV-based vertical wires. This reduction is particularly attractive in processors where it is desirable to reduce the access time between the main logic die and the L2 cache or the main memory die. Process variations in 2D ICs lead to a drop in parametric yield (as measured by speed, leakage and sales profits), which forces manufacturers to speed bin their chips and to sell slow chips at reduced prices. In this paper we develop a model to quantify the impact of process variations on the parametric yield of 3D ICs, and then we propose a number of integration strategies that use a graph-theoretic framework to maximize the performance, parametric yield and profits of 3D ICs. Comparing our proposed strategies to current yield-oblivious methods, it is demonstrated that it is possible to increase the number of 3D ICs in the fastest speed bins by almost 2x, while simultaneously reducing the number of slow ICs by 29.4%. This leads to an improvement in performance by up to 6.45% and an increase of about 12.48% in total sales revenue using up-to-date market price models.
Robust key generation from signal envelopes in wireless networks
Authors: Babak Azimi-Sadjadi, Aggelos Kiayias, Alejandra Mercado, Bulent Yener
Venue: Proceedings of the 14th ACM conference on Computer and communications security (2007)

The broadcast nature of a wireless link provides a natural eavesdropping and intervention capability to an adversary. Thus, securing a wireless link is essential to the security of a wireless network, and key generation algorithms are necessary for securing wireless links. However, traditional key agreement algorithms can be very costly in many settings, e.g. in wireless ad-hoc networks, since they consume scarce resources such as bandwidth and battery power. Traditional key agreement algorithms are not suitable for wireless ad-hoc networks since they consume scarce resources such as bandwidth and battery power. This paper presents a novel approach that couples the physical layer characteristics of wireless networks with key generation algorithms. It is based on the wireless communication phenomenon known as the principle of reciprocity which states that in the absence of interference both transmitter and receiver experience the same signal envelope. The key-observation here is that the signal envelope information can provide to the two transceivers two correlated random sources that provide sufficient amounts of entropy which can be used to extract a cryptographic key. In contrast, it is virtually impossible for a third party, which is not located at one of the transceiver's position, to obtain or predict the exact envelope; thus retrieve the key. Since in the presence of interference strict reciprocity property can not be maintained; our methodology is based on detecting deep fades to extract correlated bitstrings. In particular, we show how a pair of transceivers can reconcile such bitstrings and finally flatten their distribution to reach key agreement. In our constructions we use cryptographic tools related to randomness extraction and information reconciliation. We introduce "secure fuzzy information reconciliators" a tool that enables us to describe robust key generation systems in our setting. Finally we provide a computational study that presents a simulation of a wireless channel that demonstrates the feasibility of our approach and justifies the assumptions made in our analysis.
Further exploring the strength of prediction in the factorization of soft-decision Reed-Solomon decoding
Authors: Xinmiao Zhang
Venue: IEEE Transactions on Very Large Scale Integration (VLSI) Systems (2007)

Reed-Solomon (RS) codes are among the most widely utilized error-correcting codes in digital communication and storage systems. Among the decoding algorithms of RS codes, the recently developed Koetter-Vardy (KV) soft-decision decoding algorithm can achieve substantial coding gain, while has a polynomial complexity. One of the major steps of the KV algorithm is the factorization. Each iteration of the factorization mainly consists of root computations over finite fields and polynomial updating. To speed up the factorization step, a fast factorization architecture has been proposed to circumvent the exhaustive-search-based root computation from the second iteration level by using a root-order prediction scheme. Based on this scheme, a partial parallel factorization architecture was proposed to combine the polynomial updating in adjacent iteration levels. However, in both of these architectures, the root computation in the first iteration level is still carried out by exhaustive search, which accounts for a significant part of the overall factorization latency. In this paper, a novel iterative prediction scheme is proposed for the root computation in the first iteration level. The proposed scheme can substantially reduce the latency of the factorization, while only incurs negligible area overhead. Applying this scheme to a (255, 239) RS code, speedups of 36% and 46% can be achieved over the fast factorization and partial parallel factorization architectures, respectively.