Runtime latency detection and analysis

Detecting latency‐related problems in production environments is usually carried out at the application level with custom instrumentation. This is enough to detect high latencies in instrumented applications but does not provide all the information required to understand the source of the latency and is dependent on manually deployed instrumentation. The abnormal latencies usually start in the operating system kernel because of contention on physical resources or locks. Hence, finding the root cause of a latency may require a kernel trace. This trace can easily represent hundreds of thousands of events per second. In this paper, we propose and evaluate a methodology, efficient algorithms, and concurrent data structures to detect and analyze latency problems that occur at the kernel level. We introduce a new kernel‐based approach that enables developers and administrators to efficiently track latency problems in production and trigger actions when abnormal conditions are detected. The result of this study is a working scalable latency tracker and an efficient approach to perform stateful tracing in production. Copyright © 2016 John Wiley & Sons, Ltd.     

Convolution Filtering of Continuous Signed Distance Fields for Polygonal Meshes

Signed distance fields obtained from polygonal meshes are commonly used in various applications. However, they can have C¹ discontinuities causing creases to appear when applying operations such as blending or metamorphosis. The focus of this work is to efficiently evaluate the signed distance function and to apply a smoothing filter to it while preserving the shape of the initial mesh. The resulting function is smooth almost everywhere, while preserving the exact shape of the polygonal mesh. Due to its low complexity, the proposed filtering technique remains fast compared to its main alternatives providing C¹‐continuous distance field approximation. Several applications are presented such as blending, metamorphosis and heterogeneous modelling with polygonal meshes.     

Combined Negotiations in E-Commerce: Concepts and Architecture

Combined Negotiations are a novel and general type of negotiation, in which the user is interested in many goods or services and consequently engages in many negotiations at the same time. The negotiations are independent of each other, whereas the goods or services are typically interdependent. Using currently available technology for electronic negotiations, the user conducts each negotiation separately, and has the burden of coordinating and reconciling them. The inherent complexity of combined negotiations in B2C as well as B2B e-commerce calls for software support.In our research, we aim to devise a Combined Negotiation Support System (CNSS) to help the user conduct all the negotiations at the same time. The CNSS enables the user to control and monitor the progress of the negotiations, makes sure that the specified dependencies are respected, and applies user-defined strategy rules. We have designed such a CNSS which we call CONSENSUS. The architecture of CONSENSUS relies on workflow technology, negotiating software agents, and rule engine technology. The originality of this architecture lies in the fact that the user of CONSENSUS models the combined negotiation at build time using a workflow that captures the sequencing of the individual negotiations and the dependencies between them. At runtime, software agents are assigned to individual negotiations, and they participate in the combined negotiation as actors in the workflow. The user can monitor the progress of the combined negotiation as a whole, and the progress of individual negotiations via dedicated graphical user interfaces. We rely on rule engine technology to enable the agents to use negotiation strategies.The paper introduces combined negotiations with a usage scenario. Then, combined negotiations are detailed, along with the approach taken to cope with their complexity. Afterwards, we describe the functionality a CNSS should provide, and present the architecture of CONSENSUS, together with a discussion of the underlying concepts and technologies. Furthermore, we report on our prototype implementation of CONSENSUS and illustrate it with an example. A discussion of related and future work concludes the paper.     

Protein-induced changes during the maturation process of human dendritic cells: A 2-D DIGE approach

Dendritic cells (DCs) are unique antigen presenting cells, which upon maturation change from a specialized antigen‐capturing cell towards a professional antigen presenting cells. In this study, a 2‐D DIGE analysis of immature and mature DCs was performed, to identify proteins changing in expression upon maturation. The protein expression profile of immature and mature DCs, derived from CD14⁺ peripheral blood monocytes was investigated using two pH ranges (pH 4–7 and 6–9) (n = 4). Ninety one differentially expressed spots (p<0.01) were detected, from which we identified 74 spots (81.32%) corresponding to 41 different proteins. The proteins identified play a role in diverse processes, such as antigen processing/presentation, vesicle transport and cytoskeleton remodeling. In addition, a protein interaction network contained 29 (out of 41) proteins, suggesting that, although they functionally originate from distinct classes, these proteins are acting as a protein‐interactome. In conclusion, the proteins shown here to be altered in expression upon maturation are in line with the morphological and functional changes observed during the maturation process, providing a better understanding of the processes involved. This will open new avenues for investigating treatment regimens for immune‐associated disorders.     

College students'' high-risk sexual behavior following alcohol consumption

A new and portable electronic device called the "Digital Phagometer" is described for the time based counting of spontaneous swallowing. This device is composed of a piezoelectric sensor and a digital event counter/ recorder which can be downloaded to any IBM-compatible PC. The sensor of Digital Phagometer is placed and fixed on the coniotomy region between the cricoid and thyroid cartilage. In this way, it is capable of sensing each upward and downward movement of the larynx produced by spontaneous movement as a function of time. Spontaneous swallowing was measured 1-4 h after lunch in 21 normal subjects and 21 patients with Parkinson's disease (PD). The mean frequency of spontaneous swallowing was 0.8 counts/min in PD patients and 1.18 counts/ min in normal subjects (p < 0.05). During the intake of 200 ml water, the mean frequency of voluntary swallowing did not differ significantly between the two groups (24.6 counts/min in normals vs. 22.3 counts/min in PD patients), but the time necessary to swallow the same volume of water was longer in the PD group.     

Algorithms for a distributed IDS in MANETs

This paper presents a set of distributed algorithms that support an Intrusion Detection System (IDS) model for Mobile Ad hoc NETworks (MANETs). The development of mobile networks has implicated the need of new IDS models in order to deal with new security issues in these communication environments. More conventional models have difficulties to deal with malicious components in MANETs. In this paper, we describe the proposed IDS model, focusing on distributed algorithms and their computational costs. The proposal employs fault tolerance techniques and cryptographic mechanisms to detect and deal with malicious or faulty nodes. The model is analyzed along with related works. Unlike studies in the references, the proposed IDS model admits intrusions and malice in their own algorithms. In this paper, we also present test results obtained with an implementation of the proposed model.     

Discrete 2‐Tensor Fields on Triangulations

Geometry processing has made ample use of discrete representations of tangent vector fields and antisymmetric tensors (i.e., forms) on triangulations. Symmetric 2‐tensors, while crucial in the definition of inner products and elliptic operators, have received only limited attention. They are often discretized by first defining a coordinate system per vertex, edge or face, then storing their components in this frame field. In this paper, we introduce a representation of arbitrary 2‐tensor fields on triangle meshes. We leverage a coordinate‐free decomposition of continuous 2‐tensors in the plane to construct a finite‐dimensional encoding of tensor fields through scalar values on oriented simplices of a manifold triangulation. We also provide closed‐form expressions of pairing, inner product, and trace for this discrete representation of tensor fields, and formulate a discrete covariant derivative and a discrete Lie bracket. Our approach extends discrete/finite‐element exterior calculus, recovers familiar operators such as the weighted Laplacian operator, and defines discrete notions of divergence‐free, curl‐free, and traceless tensors–thus offering a numerical framework for discrete tensor calculus on triangulations. We finally demonstrate the robustness and accuracy of our operators on analytical examples, before applying them to the computation of anisotropic geodesic distances on discrete surfaces.     

Vulnérabilité aux erreurs de transmission de signaux sonores de haute qualité et méthodes de protection

The present paper deals with protection methods of high quality digital sound signals in presence of transmission errors. They are strongly related to the coding and the bit rate reduction methods used in the digital treatment of sound signals. Therefore, the first part is assigned to these aspects. Part 2 describes a procedure for a subjective evaluation of the impairments caused on digital sound signals by transmission errors. This procedure was used during tests realised in the ccett.Part 3 summarizes the main results of these tests and proposes a strategy for the protection which ensures a satisfying compromise between quality and simplicity.