ppxscal/embedding_network huggingface dataset:
Cryptanalysis of the RCES/RSES image encryption scheme
Authors: Shujun Li, Chengqing Li, Guanrong Chen, Kwok-Tung Lo
Venue: Journal of Systems and Software (2008)

Recently, a chaos-based image encryption scheme called RCES (also called RSES) was proposed. This paper analyses the security of RCES, and points out that it is insecure against the known/chosen-plaintext attacks: the number of required known/chosen plain-images is only one or two to succeed an attack. In addition, the security of RCES against the brute-force attack was overestimated. Both theoretical and experimental analyses are given to show the performance of the suggested known/chosen-plaintext attacks. The insecurity of RCES is due to its special design, which makes it a typical example of insecure image encryption schemes. A number of lessons are drawn from the reported cryptanalysis of RCES, consequently suggesting some common principles for ensuring a high level of security of an image encryption scheme.
Periodic sub-wavelength electron beam lithography defined photonic crystals for mode control in semiconductor lasers
Authors: Guy A. DeRose, Lin Zhu, Joyce K. S. Poon, Amnon Yariv, Axel Scherer
Venue: Microelectronic Engineering (2008)

Surface structure lasers possess lithographically defined patterns, such as gratings and waveguides, on the wafer surface and are usually fabricated without semiconductor regrowth. Optical surface structures typically require sub-micron to nano-scale accuracy in fabrication. For surface structures with more complex geometries, electron beam lithography offers the necessary flexibility, control, and accuracy in fabrication. However, a challenge with electron beam lithography is the patterning of large (~1mm by 1mm) areas while maintaining the fabrication accuracy. In this work, we demonstrate two electron beam lithography techniques in a process for the fabrication of surface structure lasers with large areas that require sub-micron to nanometer accuracy. The first technique uses proximity effect correction to fabricate two-dimensional surface gratings each consisting of approximately one million 100nm diameter circles over an 800@mm by 160@mm area. The second part of the process uses overlay lithography with an alignment accuracy better than 45nm over a 1mm by 3.2mm area to planarize waveguide array lasers.
On stability of the hamiltonian index under contractions and closures
Authors: Liming Xiong, Zdeněk Ryjáček, Hajo Broersma
Venue: Journal of Graph Theory (2005)

The hamiltonian index of a graph G is the smallest integer k such that the k-th iterated line graph of G is hamiltonian. We first show that, with one exceptional case, adding an edge to a graph cannot increase its hamiltonian index. We use this result to prove that neither the contraction of an AG(F)-contractible subgraph F of a graph G nor the closure operation performed on G (if G is claw-free) affects the value of the hamiltonian index of a graph G. AMS Subject Classification (2000): 05C45, 05C35. &copy; 2005 Wiley Periodicals, Inc. J Graph Theory
Lustre as a System Modeling Language: Lussensor, a Case-Study with Sensor Networks
Authors: Florence Maraninchi, Ludovic Samper, Kevin Baradon, Antoine Vasseur
Venue: Electronic Notes in Theoretical Computer Science (ENTCS) (2008)

We describe how we use Lustre to build global and accurate executable models of energy consumption in sensor networks, intended to be used for both simulations and formal validation. One of the key ideas is to build a component-based global model, in such a way that various abstractions of the same model can be derived by unplugging a component and plugging a more abstract (or more detailed) one. This ability to play with various abstractions that can be formally compared with one another is essential for a virtual prototyping approach connected to formal validation tools. We comment on the properties of Lustre and its development environment that make this approach feasible.
Application of kalman filters to identify unexpected change in blogs
Authors: Paul Logasa Bogen,  II, Joshua Johnston, Unmil P. Karadkar, Richard Furuta, Frank Shipman
Venue: Proceedings of the 8th ACM/IEEE-CS joint conference on Digital libraries (2008)

Information on the Internet, especially blog content, changes rapidly. Users of information collections, such as the blogs hosted by technorati.com, have little, if any, control over the content or frequency of these changes. However, it is important for users to be able to monitor content for deviations in the expected pattern of change. If a user is interested in political blogs and a blog switches subjects to a literary review blog, the user would want to know of this change in behavior. Since pages may change too frequently for manual inspection for "unwanted" changes, an automated approach is wanted. In this paper, we explore methods for indentifying unexpected change by using Kalman filters to model blog behavior over time. Using this model, we examine the history of several blogs and determine methods for flagging the significance of a blog's change from one time step to the next. We are able to predict large deviations in blog content, and allow user-defined sensitivity parameters to tune a statistical threshold of significance for deviation from expectation.
Pre-authentication filters: providing dos resistance for signature-based broadcast authentication in sensor networks
Authors: Qi Dong, Donggang Liu, Peng Ning
Venue: Proceedings of the first ACM conference on Wireless network security (2008)

Recent studies have demonstrated that it is possible to perform public key cryptographic operations on the resource-constrained sensor platforms. However, the significant resource consumption imposed by public key cryptographic operations makes such mechanisms easy targets of Denial- of Service (DoS) attacks. For example, if digital signatures such as ECDSA are used directly for broadcast authentication without further protection, an attacker can simply broadcast forged packets and force the receiving nodes to perform a large number of unnecessary signature verifications, eventually exhausting their battery power. This paper studies how to deal with such DoS attacks when signatures are used for broadcast authentication in sensor networks. In particular, this paper presents two filtering techniques, a group-based filter and a key chain-based filter, to handle DoS attacks against signature verification. Both methods can significantly reduce the number of unnecessary signature verifications that a sensor node has to perform. The analytical results also show that these two techniques are efficient and effective for resource-constrained sensor networks.
Combinatorial construction of locally testable codes
Authors: Or Meir
Venue: Proceedings of the 40th annual ACM symposium on Theory of computing (2008)

An error correcting code is said to be locally testable if there is a test that checks whether a given string is a codeword, or rather far from the code, by reading only a constant number of symbols of the string. Locally Testable Codes (LTCs) were first systematically studied by Goldreich and Sudan (J. ACM 53(4)) and since then several Constructions of LTCs have been suggested. While the best known construction of LTCs by Ben-Sasson and Sudan (STOC 2005) and Dinur (J. ACM 54(3)) achieves very efficient parameters, it relies heavily on algebraic tools and on PCP machinery. In this work we present a new and arguably simpler construction of LTCs that is purely combinatorial, does not rely on PCP machinery and matches the parameters of the best known construction. However, unlike the latter construction, our construction is not entirely explicit.
An Embedded Real-Time Surveillance System: Implementation and Evaluation
Authors: Fredrik Kristensen, Hugo Hedberg, Hongtu Jiang, Peter Nilsson, Viktor Öwall
Venue: Journal of Signal Processing Systems (2008)

This paper presents the design of an embedded automated digital video surveillance system with real-time performance. Hardware accelerators for video segmentation, morphological operations, labeling and feature extraction are required to achieve the real-time performance while tracking will be handled in software in an embedded processor. By implementing a complete embedded system, bottlenecks in computational complexity and memory requirements can be identified and addressed. Accordingly, a memory reduction scheme for the video segmentation unit, reducing bandwidth with more than 70%, and a low complexity morphology architecture that only requires memory proportional to the input image width, have been developed. On a system level, it is shown that a labeling unit based on a contour tracing technique does not require unique labels, resulting in more than 50% memory reduction. The hardware accelerators provide the tracking software with image objects properties, i.e. features, thereby decoupling the tracking algorithm from the image stream. A prototype of the embedded system is running in real-time, 25 fps, on a field programmable gate array development board. Furthermore, the system scalability for higher image resolution is evaluated.
Complexity and spectral analysis of the heart rate variability dynamics for distant prediction of paroxysmal atrial fibrillation with artificial intelligence methods
Authors: Yuriy V. Chesnokov
Venue: Artificial Intelligence in Medicine (2008)

Objective: Paroxysmal atrial fibrillation (PAF) is a serious arrhythmia associated with morbidity and mortality. We explore the possibility of distant prediction of PAF by analyzing changes in heart rate variability (HRV) dynamics of non-PAF rhythms immediately before PAF event. We use that model for distant prognosis of PAF onset with artificial intelligence methods. Methods and materials: We analyzed 30-min non-PAF HRV records from 51 subjects immediately before PAF onset and at least 45min distant from any PAF event. We used spectral and complexity analysis with sample (SmEn) and approximate (ApEn) entropies and their multiscale versions on extracted HRV data. We used that features to train the artificial neural networks (ANNs) and support vector machine (SVM) classifiers to differentiate the subjects. The trained classifiers were further tested for distant PAF event prognosis on 16 subjects from independent database on non-PAF rhythm lasting from 60 to 320min before PAF onset classifying the 30-min segments as distant or leading to PAF. Results: We found statistically significant increase in 30-min non-PAF HRV recordings from 51 subjects in the VLF, LF, HF bands and total power (p
On s-intersecting curves and related problems
Authors: Sarit Buzaglo, Rom Holzman, Rom Pinchasi
Venue: Proceedings of the twenty-fourth annual symposium on Computational geometry (2008)

Let P be a set of n points in the plane and let C be a family of simple closed curves in the plane each of which avoids the points of P. For every curve C ∈ C we denote by disc(C) the region in the plane bounded by C. Fix an integer s > 0 and assume that every two curves in C intersect at most s times and that for every two curves C,C' ∈ C the intersection disc(C) ∩ disc(C') is a connected set. We consider the family F = {P ∩ disc(C) | C ∈ C}. When s is even, we provide sharp bounds, in terms of n, s, and k, for the number of sets in F of cardinality k, assuming that ∩C ∈Cdisc(C) is nonempty. In particular, we provide sharp bounds for the number of halving pseudo-parabolas for a set of n points in the plane. Finally, we consider the VC-dimension of F and show that F has VC-dimension at most s+1.
VNIDA: Building an IDS Architecture Using VMM-Based Non-Intrusive Approach
Authors: Xiantao Zhang, Qi Li, Sihan Qing, Huanguo Zhang
Venue: Proceedings of the First International Workshop on Knowledge Discovery and Data Mining (2008)

Intrusion detection system (IDS) has been introduced and broadly applied to prevent unauthorized access to system resource and data for several years. However, many problems are still not well resolved in most of IDS, such as detection evasion, intrusion containment. In order to resolve these problems, we propose a novel flexible architecture VNIDA which is based on virtual machine monitor (VMM) and has no-intrusive behavior to target system after studying popular IDS architectures. In this architecture, a separate intrusion detection domain (IDD) is added to provide intrusion detection services for all virtual machines. Specially, an IDD helper is introduced to take response to the intrusions according to the security policies. Moreover, event sensors and IDS stub, as the core components of IDS, are separately isolated from target systems, so strong reliability is also achieved in this architecture. To show the feasibility of the VNIDA, we implement a prototype based on the proposed architecture. Based on the prototype, we employed some rootkits to evaluate our VNIDA, and the results shows that VNIDA has the ability to detect them efficiently, even some potential intrusions. In addition, system performance evaluation also shows that VNIDA only introduce less than 1.25% extra overhead.
Visualizing the Analysis of Dynamically Adaptive Systems Using i* and DSLs
Authors: Pete Sawyer, Nelly Bencomo, Danny Hughes, Paul Grace, Heather J. Goldsby, Betty H. C. Cheng
Venue: Proceedings of the Second International Workshop on Requirements Engineering Visualization (2007)

Self-adaptation is emerging as a crucial enabling capability for many applications, particularly those deployed in dynamically changing environments. One key challenge posed by Dynamically Adaptive Systems (DASs) is the need to handle changes to the requirements and corresponding behavior of a DAS in response to varying environmental conditions. In this paper we propose a visual model-driven approach that uses the i* modeling language to represent goal models for the DAS requirements. Our approach applies a rigorous separation of concerns between the requirements for the DAS to operate in stable conditions and those that enable it to adapt at run-time to enable it to cope with changes in its environment. We further show how requirements derived from the i* modeling can be used by a domain-specific language to achieve requirements modeldriven development. We describe our experiences with applying this approach to GridStix, an adaptive flood warning system, deployed on the River Ribble in North Yorkshire, England.
Test compression saves bits, cycles, and money
Authors: Tim Cheng
Venue: IEEE Design Test (2008)

Test data compression became an active research topic in the late 1990s, and has now become a standard offering within commercial DFT solutions. This issue of IEEE Design & Test features a special issue on the current state of test compression. This issue of D&T also concludes the theme of design and test of RFIC chips (featured in the Jan./Feb. 08 issue), with two additional articles. In addition, this issue features two general-interest articles and an interview with DRAM inventor Bob Dennard.
The hardness of approximate optima in lattices, codes, and systems of linear equations
Authors: S. Arora
Venue: Proceedings of the 1993 IEEE 34th Annual Foundations of Computer Science (1993)

We prove the following about the Nearest Lattice Vector Problem (in any l/sub p/ norm), the Nearest Code-word Problem for binary codes, the problem of learning a halfspace in the presence of errors, and some other problems. 1. Approximating the optimum within any constant factor is NP-hard. 2. If for some /spl epsiv/>0 there exists a polynomial time algorithm that approximates the optimum within a factor of 2/sup log(0.5-/spl epsiv/)/ /sup n/ then NP is in quasi-polynomial deterministic time: NP/spl sube/DTIME(n/sup poly(log/ /sup n)/). Moreover, we show that result 2 also holds for the Shortest Lattice Vector Problem in the l/sub /spl infin// norm. Improving the factor 2/sup log(0.5-/spl epsiv/)/ /sup n/ to /spl radic/(dim) for either of the lattice problems would imply the hardness of the Shortest Vector Problem in l/sub 2/ norm; an old open problem. Our proofs use reductions from few-prover, one-round interactive proof systems, either directly, or through a set-cover problem.
Switching times variation of MOSFET devices with temperature and high-field stress
Authors: R. Habchi, C. Salame, R. El Bitar, P. Mialhe
Venue: Microelectronics Journal (2008)

Switching times of power MOSFET devices are investigated as function of temperature and high-field stress. Measurements show that important variations are obtained on the devices turn-on time. The threshold voltage is decreasing with temperature and varies with stress, especially at low temperatures. The oxide leakage current is found to be having safe values even at high temperatures, stressing the devices does not increase the leakage current to unsafe values except for very high temperatures.
Nonrigid Structure-from-Motion: Estimating Shape and Motion with Hierarchical Priors
Authors: Lorenzo Torresani, Aaron Hertzmann, Chris Bregler
Venue: IEEE Transactions on Pattern Analysis and Machine Intelligence (2008)

This paper describes methods for recovering time-varying shape and motion of non-rigid 3D objects from uncalibrated 2D point tracks. For example, given a video recording of a talking person, we would like to estimate the 3D shape of the face at each instant, and learn a model of facial deformation. Time-varying shape is modeled as a rigid transformation combined with a non-rigid deformation. Reconstruction is ill-posed if arbitrary deformations are allowed, and thus additional assumptions about deformations are required. We first suggest restricting shapes to lie within a low-dimensional subspace, and describe estimation algorithms. However, this restriction alone is insufficient to constrain reconstruction. To address these problems, we propose a reconstruction method using a Probabilistic Principal Components Analysis (PPCA) shape model, and an estimation algorithm that simultaneously estimates 3D shape and motion for each instant, learns the PPCA model parameters, and robustly fills-in missing data points. We then extend the model to model temporal dynamics in object shape, allowing the algorithm to robustly handle severe cases of missing data.
Business services as communication patterns: a work practice approach for analyzing service encounters
Authors: R. J. Clarke, A. G. Nilsson
Venue: IBM Systems Journal (2008)

In this paper, we describe an approach to business processes and services which views work practices as recurrent patterns of communication called genres. Although defining work practices in this way is unorthodox, it provides two major advantages. First, the communication resources employed by the parties engaging in a service transaction can be clearly described, understood, and communicated. Business processes and services can be differentiated on the basis of the structural and functional arrangement of their constituent genres. This provides a view of a business process or service that is technology-independent. Second, using this approach means that work practices are defined contextually-an important consideration when trying to understand how business processes and services will influence organizations. Because genres are represented using directed graphs, prototypes can be developed to assist during the analysis of existing services and the design of new ones. Structural and functional change of genres can be used to reveal how a specific service is evolving within an organization. This enables us to determine if business demands have changed, something that is difficult to achieve using conventional service engineering approaches.
Existence of perfect equilibria in a class of multigenerational stochastic games of capital accumulation
Authors: Łukasz Balbus, Andrzej S. Nowak
Venue: Automatica (Journal of IFAC) (2008)

In this paper we introduce a model of multigenerational stochastic games of capital accumulation where each generation consists of m different players. The main objective is to prove the existence of a perfect stationary equilibrium in an infinite horizon game. A suitable change in the terminology used in this paper provides (in the case of perfect altruism between generations) a new Nash equilibrium theorem for standard stochastic games with uncountable state space.
Effects of Instruction-Set Extensions on an Embedded Processor: A Case Study on Elliptic Curve Cryptography over GF(2/sup m/)
Authors: Sandro Bartolini, Irina Branovic, Roberto Giorgi, Enrico Martinelli
Venue: IEEE Transactions on Computers (2008)

Elliptic curve (EC) cryptography is expected to have a significant role in enabling information security in constrained embedded devices. In order to be efficient on a target architecture, EC cryptosystems (ECC) require an accurate choice/tuning of the algorithms that perform the underlying mathematical operations. This paper performs a cycle-level analysis of the dependencies of ECC performance from the interaction between the features of the mathematical algorithms and the actual architectural and microarchitectural features of an ARM XScale processor. The paper investigates the origin of performance through the breakdown of execution into the cycles spent in the different activities at field- and at elliptic-curve levels. In addition, we perform a cycle-level analysis of a modified ARM processor that includes in its datapath a word-level finite field polynomial multiplier (poly_mul). The paper points out the most advantageous mix of EC parameters both for the standard ARM XScale platform and for the one equipped with the poly_mul unit. In this way, the latter allows more than 41% execution time reduction on the considered benchmarks. Then, the paper analyses the correlation between EC benchmark performance and the possible architectural organizations of a processor equipped with poly_mul unit(s). For instance, only superscalar pipelines can exploit the features of out-of-order execution and only very complex organizations (e.g. 4-way superscalar) can exploit a high number of available ALUs. Conversely, we show that there are no benefits in endowing the processor with more than one poly_mul and we point out a possible trade-off between performance and complexity increase: 2-way in-order/out-of-order pipeline allows +50% and +90% IPC, respectively. Finally, we show that there are not critical constraints on the latency and pipelining capability of the poly_mul unit.
Characterization of bonded silicon-on-aluminum-nitride wafers with RBS, TEM and HRXRD techniques
Authors: Chuanling Men, Chenglu Lin
Venue: Microelectronic Engineering (2008)

Bonded silicon-on-insulator (SOI) materials via the Smart-cut^T^M (or ion-cut) process attract increasing interests due to their great capability and versatility in fabricating novel virtual substrates. Previously we reported the successful fabrication of silicon-on-aluminum-nitride (SOAN) structure with smart-cut process [C.L. Men, Z. Xu, Z. An, X.Y. Xie, M. Zhang, C.L. Lin, Physica B 324 (2002) 229]. In this work, we characterize the bonded SOAN structure with Rutherford backscattering spectroscopy (RBS), transmission electron microscopy (TEM) together with Kikuchi line diffraction patterns, and high resolution X-ray diffraction (HRXRD) techniques. It is found that, after smart-cut process, the top Si layer preserves a rather good single crystalline quality, while strain is induced in top Si and can be altered in the annealing step. The rotational misalignment during bonding step can be evaluated by Kikuchi line patterns. Our discussions here may be common for all bonded virtual substrates via smart-cut technology.