Keywords: Wearable computers;Sensors;Real-time systems;Glucose;Insulin;Prediction algorithms;Protocols;Blood;Machine learning;Blood glucose prediction;health information systems;machine learning;wearable sensors

Background and Objective: Degenerative meniscus tissue has been associated with a lower elastic modulus and can lead to the development of arthrosis. Safe intraoperative measurement of in vivo elastic modulus of the human meniscus could contribute to a better understanding of meniscus health, and for developing surgical simulators where novice surgeons can learn to distinguish healthy from degenerative meniscus tissue. Such measurement can also support intraoperative decision-making by providing a quantitative measure of the meniscus health condition. The objective of this study is to demonstrate a method for intraoperative identification of meniscus elastic modulus during arthroscopic probing using an adaptive observer method. Methods: Ex vivo arthroscopic examinations were performed on five cadaveric knees to estimate the elastic modulus of the anterior, mid-body, and posterior regions of lateral and medial menisci. Real-time intraoperative force–displacement data was obtained and utilized for modulus estimation through an adaptive observer method. For the validation of arthroscopic elastic moduli, an inverse parameter identification approach using optimization, based on biomechanical indentation tests and finite element analyses, was employed. Experimental force–displacement data in various anatomical locations were measured through indentation. An iterative optimization algorithm was employed to optimize elastic moduli and Poisson’s ratios by comparing experimental force values at maximum displacement with the corresponding force values from linear elastic region-specific finite element models. Finally, the estimated elastic modulus values obtained from ex vivo arthroscopy were compared against optimized values using a paired t-test. Results: The elastic moduli obtained from ex vivo arthroscopy and optimization showcased subject specificity in material properties. Additionally, the results emphasized anatomical and regional specificity within the menisci. The anterior region of the medial menisci exhibited the highest elastic modulus among the anatomical locations studied (9.97±3.20MPa from arthroscopy and 5.05±1.97MPa from finite element-based inverse parameter identification). The paired t-test results indicated no statistically significant difference between the elastic moduli obtained from arthroscopy and inverse parameter identification, suggesting the feasibility of stiffness estimation using arthroscopic examination. Conclusions: This study has demonstrated the feasibility of intraoperative identification of patient-specific elastic modulus for meniscus tissue during arthroscopy.

Keywords: Arthroscopic meniscus examination, Adaptive observer, Indentation testing, Finite element analysis, Inverse parameter identification, Elastic modulus

The real-time implementation of large-scale structural models without sacrificing their physical realism is challenging. This paper introduces a conceptual framework named the Co-rotational Reduced Order Kalman Filter Finite Element Method (CROKF-FEM) for the realistic linear elastic analysis of large-scale structures in real-time. The standard linear finite element method (FEM) is employed for high-precision deformation modeling, and element matrices are pre-computed in the space domain. To avoid the inflated elements of standard linear FEM due to large rotation, a co-rotational formulation is devised. Then, the system is discretized in the time domain using the Wilson- θ implicit integration scheme and a further state-space model is developed. Subsequently, a reduced-order model is constructed using the balanced truncation method. Finally, a Kalman filter algorithm is created on the reduced model for online estimation. This approach preserves all the benefits of traditional linear FEM with a similar deformation accuracy while achieving significant real-time performance.

Keywords: Kalman Filtering, Model Order Reduction, Corotational Formulation, Finite Element Method, Real-time Modeling, Soft Tissue Deformation

In this paper, we examine the region- and layer-specific collagen fiber morphology via second harmonic generation (SHG) in combination with planar biaxial tension testing to suggest a structure-based constitutive model for the human meniscal tissue. Five lateral and four medial menisci were utilized, with samples excised across the thickness from the anterior, mid-body, and posterior regions of each meniscus. An optical clearing protocol enhanced the scan depth. SHG imaging revealed that the top samples consisted of randomly oriented fibers with a mean fiber orientation of 43.3^o. The bottom samples were dominated by circumferentially organized fibers, with a mean orientation of 9.5^o. Biaxial testing revealed a clear anisotropic response, with the circumferential direction being stiffer than the radial direction. The bottom samples from the anterior region of the medial menisci exhibited higher circumferential elastic modulus with a mean value of 21 MPa. The data from the two testing protocols were combined to characterize the tissue with an anisotropic hyperelastic material model based on the generalized structure tensor approach. The model showed good agreement in representing the material anisotropy with a mean r² = 0.92.

Simon and Schön are commonly seen to represent two conflicting views on design method, but this interpretation has been challenged in recent years. In this paper we discuss their differences and agreements in more depth. Both of them agree on a rationality which is distinct from science and its reliance on universal truth. They depend on a practical reason, and what Aristotle calls the calculative part of the soul, which deals with the contingencies of real world problems, and still let us know, and share, truth. One discrepancy remains between Simon and Schön. Simon does not tell us how we identify the changing goals of man. Schön addresses this by invoking the distinctly human power to see-as.

Keywords: design methodology, reflective practice, engineering design, philosophy of design, logic of design

It is often difficult to teach mathematics for understanding. Many students seem to prefer to learn computational skills by rote, and seem to remember very little of the course contents the following semester. The reasons for this are surely manifold. This paper reviews the concept of understanding, looking particularly towards the meaning it has in hermeneutic philosophy. The known distinction between hermeneutical and epistemological understanding is resituated in mathematics, and we argue that it is the hermeneutic understanding which is most relevant when mathematics is taught as a support subject for engineering and other professions.

Pseudo-random number generation is a fundamental problem in computer programming. In the case of sequential processing the problem is very well researched, but parallel processing raises new problems whereof far too little is currently understood.

Splittable pseudo-random generators have been proposed to meet the challenges of parallelism. While applicable to any programming paradigm, they are designed to be particularly suitable for pure functional programming. In this paper we review and evaluate known constructions of such generators, and we identify flaws in several large classes of generators, including Lehmer trees, the implementation in Haskell's standard library, leapfrog, and subsequencing (substreaming).

Keywords: splittable pseudo-random number generators, Lehmer tree, Monte Carlo tree, parallel programming, pure functional programming, Haskell

Tug fleet optimisation algorithms can be designed to solve the problem of dynamically positioning a fleet of tugs in order to mitigate the risk of oil tanker drifting accidents. In this paper, we define the 1D tug fleet optimisation problem and present a receding horizon genetic algorithm for solving it. The algorithm can be configured with a set of cost functions such that each configuration effectively constitute a unique tug fleet optimisation algorithm. To measure the performance, or merit, of such algorithms, we propose two evaluation heuristics and test them by means of a computational simulation study. Finally, we discuss our findings and some of our related work on a parallel implementation and an alternative 2D nonlinear mixed integer programming formulation of the problem.

Abstract The Coordination Reform of 2012 requires Norwegian municipalities and regional health authorities to enter into legally binding service agreements. Although several research projects have been undertaken to analyse the implications of this reform, there is no central database where researches can be given access and analyse the service agreements. In this paper we present how we use model-driven software engineering and user-centric design in an initial development of an information system designed to allow researches to access and analyse service agreements. For this project, it was crucial to discuss the requirements of the system with domain-experts at a high level of abstraction in order to elicit feedback so that the development could proceed at a fast pace and in the right direction. Furthermore, given time and resource constraints, we elected to use a model driven approach using automatic code generation coupled with high-productivity frameworks. In this way we were able to create prototypes so that the developers could get fast feedback from the domain-experts and improvements could be implemented with minimal effort.

Keywords: Model-driven Software Engineering, Coordination Reforms in healthcare, Metamodelling, MVCore

The main threat against fingerprinting systems is collusion attacks. The attack most commonly assumed in the literature is a combination of averaging the collusion fingerprints and additive noise. In this correspondence, we demonstrate that the recently proposed fingerprinting scheme of Kuribayashi's is very vulnerable to certain nonlinear collusion attacks.

Keywords: data compression;fingerprint identification;image coding; image denoising;image watermarking; Kuribayashi fingerprinting scheme;additive noise; collusion fingerprints;fingerprinting systems; nonlinear collusion attacks;Additive noise; Detectors;Discrete cosine transforms; Educational institutions;Interference;Transform coding; Watermarking;Fingerprinting;collusion attack;watermarking

We formalize a new attack model for collusion secure codes, incorporating attacks on the underlying watermarking scheme as well as cut-and-paste attacks traditionally considered for collusion secure codes. We use this model to analyze the collusion resistance of two versions of the Tardos code, both for binary and nonbinary alphabets. The model allows us to consider different signal processing attacks on the content, namely the addition of noise and averaging attacks. The latter may result in content segments that have multiple watermarks embedded. We study two versions of the q-ary Tardos code in which the accusation method has been modified so as to allow for the detection of multiple symbols in the same content segment. We show that both variants yield efficient codes in the new model, parametrized for realistic attacker strengths.

Keywords: fingerprint identification;image watermarking;Tardos fingerprinting codes;accusation method;binary alphabets;collusion resistance;collusion secure codes;combined digit model;content segment;cut-and-paste attacks;nonbinary alphabets;q-ary Tardos code;signal processing attacks;watermarking scheme;Analytical models;Detectors;Mathematical model;Noise;Watermarking;Collusion attacks;fingerprinting;watermarking

The Deletion-Insertion Correcting Code construction proposed by Davey and MacKay consists of an inner code that recovers synchronization and an outer code that provides substitution error protection. The inner code uses low-weight codewords which are added (modulo two) to a pilot sequence. The receiver is able to synchronise on the pilot sequence in spite of the changes introduced by the added codeword. The original bit-level formulation of the inner decoder assumes that all bits in the sparse codebook are identically and independently distributed. Not only is this assumption inaccurate, but it also prevents the use of soft a- priori input to the decoder. We propose an alternative symbol-level inner decoding algorithm that takes the actual codebook into account. Simulation results show that the proposed algorithm has an improved performance with only a small penalty in complexity, and it allows other improvements using inner codes with larger minimum distance.

Keywords: turbo codes;Davey-MacKay construction;alternative symbol-level inner decoding algorithm;deletion-insertion correcting code construction;improved decoding algorithm;inner decoder;nonbinary codes;pilot sequence;sparse codebook;substitution error protection;turbo codes;Communications Society;Decoding;Delta modulation;Demodulation;Error correction codes;Iterative algorithms;Partial transmit sequences;Peer to peer computing;Turbo codes;Watermarking

Several open questions in coding theory relate to non-existence or construction of certain optimal codes. Many previous problems of this kind have been solved by studying possible weight enumerators. A couple of authors in this decade have proposed using higher weights (generalised Hamming weights) to a similar effect. In this paper we suggest one approach based on the weight hierarchy, and it allows us to conduct an extremely rapid computer search to prove that there are exactly two inequivalent [36,8,16] codes. The technique can also be used to gain new information about the weight hierarchy of the putative [72,36,16] code, but not yet enough to say if it exists or not.

We introduce a new attack model for collusion-secure codes, called the combined digit model, which represents signal processing attacks against the underlying watermarking level better than existing models. In this paper, we analyze the performance of two variants of the Tardos code and show that both variants can accommodate the new model and resist collusion attacks with only a modest increase in code length as compared to the results for the commonly used restricted digit model.

Keywords: codes;watermarking;Tardos fingerprinting codes;collusion-secure codes;combined digit model;restricted digit model;signal processing;watermarking level;Codes;Data security;Fingerprint recognition;Forensics;Information security;Performance analysis;Resists;Signal processing;Signal processing algorithms;Watermarking

The Davey-MacKay construction is a deletion-insertion correcting code scheme consisting of an inner code that functions as a pilot sequence to which the receiver seeks to synchronize, and an outer code that provides error protection. We analyse the performance of the inner code in isolation, arguing that these codes provide unequal protection, and demonstrate empirically that the error rate is dependent on the date symbol values. We also propose modifications to the code construction that alleviate this asymmetry. Simulation results show that these codes have an improved performance with no penalty.

Keywords: error correction codes;Davey-MacKay construction;code construction;deletion-insertion correcting code scheme;error protection code;inner code;outer code;Decoding;Delta modulation;Error analysis;Error correction codes;Information theory;Parity check codes;Partial transmit sequences;Performance analysis;Protection;Watermarking

With a digital fingerprinting scheme, a vendor of digital copies of copyrighted material marks each individual copy with a unique fingerprint. If an illegal copy appears, it can be traced back to one or more guilty pirates due to this fingerprint. A coalition of pirates may combine their copies to produce an unauthorized copy with a false, hybrid fingerprint. It is often assumed in the literature that the members of the collusion will make equal contributions to the hybrid fingerprint, because nobody will accept an increased risk of being caught. We argue that no such assumption is valid a priori, and we show that a published solution by Sebe and Domingo-Ferrer can be broken by breaking the assumption.

Keywords: copyright;fingerprint identification;image coding;copyrighted material;digital copy protection;digital fingerprinting scheme;hybrid fingerprint;illegal copying;Collusion-attack;collusion-secure code (CSC);digital fingerprinting;scattering codes

In this paper we consider the use of q-ary turbo codes on abstract q-ary channels. Simulations show that our 16-ary codes perform well on the q-ary symmetric channel. This validates their suitability as outer codes in non-binary applications. We also compare with the performance of same codes on conventional PSK and QAM modulation, and demonstrate an application of these codes to the insertion/deletion channel.

Keywords: channel coding;phase shift keying;quadrature amplitude modulation;turbo codes;PSK modulation;QAM modulation;insertion/deletion channel;nonbinary turbo codes;q-ary channels;q-ary turbo codes;Construction industry;Decoding;Delta modulation;Error analysis;Modulation;Turbo codes;Watermarking;deletion-insertion correcting codes;non-binary codes;q-ary symmetric channel;turbo codes

Digital fingerprinting has been suggested for copyright protection. Using a watermarking scheme, a fingerprint identifying the buyer is embedded in every copy sold. If an illegal copy appears, it can be traced back to the guilty user. By using collusion-secure codes, the fingerprinting system is made secure against cut-and-paste attacks. In this paper we study the interface between the collusion-secure fingerprinting codes and the underlying watermarking scheme, and we construct several codes which are both error-correcting and collusion-secure. Error-correction makes the system robust against successful attacks on the watermarking layer.

Keywords: Collusion-secure fingerprinting; Copyright protection; Error-correcting codes; Watermarking; Soft-decision decoding

Spread-spectrum watermarking is generally considered to be robust against collusion attacks, and thereby suitable for digital fingerprinting. We have previously introduced the minority extreme attack (IWDW ’07), and showed that it is effective against orthogonal fingerprints. In this paper, we show that it is also effective against random Gaussian fingerprint. Furthermore, we develop new randomised attacks which counter the effect of the decoder preprocessing of Zhao et al.

Digital fingerprinting has been suggested for copyright protection. Using a watermarking scheme, a fingerprint identifying the buyer is embedded in every copy sold. If an illegal copy appears, it can be traced back to the guilty user. By using collusion-secure codes, the fingerprinting system is made secure against cut-and-paste attacks. In this paper we study the interface between the collusion-secure fingerprinting codes and the underlying watermarking scheme, and we construct several codes which are both error-correcting and collusion-secure. Error-correction makes the system robust against successful attacks on the watermarking layer

Keywords: error correction codes;fingerprint identification;watermarking;collusion-secure codes;copyright protection;cut-and-paste attacks;digital fingerprinting;error-correcting code;watermarking;Computer errors;Copyright protection;Decoding;Error correction codes;Fingerprint recognition;Image segmentation;Marketing and sales;Robustness;Steganography;Watermarking;collusion-secure fingerprinting;copyright protection;error-correcting codes;soft-decision decoding;watermarking

Digital fingerprinting is a forensic method against illegal copying. The distributor marks each individual copy with a unique fingerprint. If an illegal copy appears, it can be traced back to one or more guilty pirates due to this fingerprint. To work against a coalition of several pirates, the fingerprinting scheme must be based on a collusion-secure code. This paper addresses binary collusion-secure codes in the setting of Boneh and Shaw (1995/1998). We prove that the Boneh-Shaw scheme is more efficient than originally proven, and we propose adaptations to further improve the scheme. We also point out some differences between our model and others in the literature.

Keywords: binary codes;copy protection;Boneh-Shaw fingerprinting;binary collusion-secure codes;forensic method;illegal copying;Copyright protection;Councils;Data security;Fingerprint recognition;Forensics;Law;Legal factors;Legislation;Marketing and sales;Motion pictures;Collusion-secure codes;copyright protection;digital fingerprinting (FP);traitor tracing

We compute the second support weight distribution of the Kasami codes.

Keywords: Galois fields, dual codes, linear codes GF, Galois field, Kasami code, SWD, dual code, linear code, support weight distribution

Separating codes find applications in many fields including automata theory and digital fingerprinting. It is known that the Kerdock code of sufficient order is (2,1)- and (2,2)-separating, but the separating weight is only known by a lower bound due to Sagalovich. In this correspondence, we prove that the lower bound on the (2,1)-separating weight is met with equality.

Keywords: automata theory;binary codes;linear codes;(2, 1)-separating weight;automata theory;binary Kerdock code;digital fingerprinting;linear codes;separating codes;Binary codes;Councils;Hamming distance;Informatics;65;Fingerprinting;Kerdock code;linear codes over;separating systems

We show how to compute the support weight distribution A/sub i//sup r/ for r/spl ges/k-d/sub 2//sup /spl perp//+3, where d/sub 2//sup /spl perp// is the second minimum support weight of a code, provided the weight enumerator of the dual code is known.

Keywords: dual codes dual code, support weight distribution, weight enumerator

The combinatorial concept of separating systems has numerous applications, such as automata theory, digital fingerprinting, group testing, and hashing. In this correspondence, we derive upper bounds on the size of codes with various separating properties.

Keywords: combinatorial mathematics;error correction codes;automata theory;combinatorial concept;digital finger printing;error-correcting codes;group testing;hashing;separating codes;separating system;superimposed codes;upper bound;Cryptography;Cyclic redundancy check;Error-correcting codes;hashing;separating systems;superimposed codes

Separating codes have recently been applied in the construction of collusion secure fingerprinting schemes. They are related to other combinatorial concepts like intersecting codes, superimposed codes, hashing families, and group testing. In this paper we study some good, binary asymptotic constructions of such codes.

Keywords: separating systems, fingerprinting, BCH codes, Kasami codes

Let Γ be a code of length n. Then x is called a descendant of the coalition of codewords a,b,…,e if xi∈ai,bi,…,ei for i=1,…,n. We study codes with the following property: any two non-intersecting coalitions of a limited size have no common descendant. We present constructions based on linear intersecting codes.

Keywords: Intersecting code, Separating code, Copyright protection

The theory of separating systems has been applied in different areas of science and technology such as automata synthesis, technical diagnosis, and authenticating ownership claims. Constructions of (2,2)-separating systems derived from error-correcting codes are given, together with bounds on their parameters based on distance considerations.

Keywords: concatenated codes;error correction codes;linear codes;2,2-separating systems;bounds;concatenated codes;copyright protection;distance considerations;error-correcting codes;linear codes;watermarking;Linear code;Sufficient conditions;Terminology;Watermarking

A projective multiset is a collection of projective points, which are not necessarily distinct. A linear code can be represented as a projective multiset, by taking the columns of a generator matrix as projective points. Projective multisets have proved very powerful in the study of generalised Hamming weights. In this paper we study relations between a code and its dual.

Keywords: linear codes, projective multiset, weight hierarchy, greedy weights, dual code

We present the relation between product codes and projective multisets, and give a lower bound on the greedy weights of product codes

Keywords: linear codes;set theory;greedy weights;linear codes;lower bound;product codes;projective multisets;Councils;Informatics;Linear code;Product codes;Subspace constraints;Tensile stress

The weight hierarchy of a linear [n,k;q] code C over GF(q) is the sequence (d1,d2,…,dk) where dr is the smallest support weight of an r-dimensional subcode of C. Linear codes may be classified according to a set of chain and non-chain conditions, the extreme cases being codes satisfying the chain condition (due to Wei and Yang) and extremal, non-chain codes (due to Chen and Kløve). This paper gives upper bounds on the weight hierarchies of the latter class of codes.

Keywords: Weight hierarchy, Chain condition, Linear codes, Projective multiset

The weight of a code is the number of coordinate positions where no codeword is zero. The rth minimum weight dr is the least weight of an r-dimensional subcode. Wei and Yang (1993) gave a conjecture about the minimum weights for some product codes. In this article, we find a relation between product codes and the Segre embedding of a pair of projective systems, and we use this to prove the conjecture

Keywords: linear codes;set theory;Segre embedding;coordinate positions;linear code;minimum weight;minimum weights;product codes;projective multiset;projective systems;subcode;weight hierarchy;Informatics;Linear code;Product codes;Tensile stress;Vectors

We use projective multisets (projective systems) to find upper bounds on the weight hierarchies for a special class of codes, namely the extremal non-chain codes. Several code constructions exist meeting the bounds with equality

Keywords: linear codes;code constructions;extremal nonchain codes;higher weights;linear codes;projective multisets;projective systems;upper bounds;weight hierarchies;Algebra;Binary codes;Galois fields;Hamming weight;Informatics;Upper bound