An Internet-based negotiation server for e-commerce

This paper describes the design and implementation of a replicable, Internet-based negotiation server for conducting bargaining-type negotiations between enterprises involved in e-commerce and e-business. Enterprises can be buyers and sellers of products/services or participants of a complex supply chain engaged in purchasing, planning, and scheduling. Multiple copies of our server can be installed to complement the services of Web servers. Each enterprise can install or select a trusted negotiation server to represent his/her interests. Web-based GUI tools are used during the build-time registration process to specify the requirements, constraints, and rules that represent negotiation policies and strategies, preference scoring of different data conditions, and aggregation methods for deriving a global cost-benefit score for the item(s) under negotiation. The registration information is used by the negotiation servers to automatically conduct bargaining type negotiations on behalf of their clients. In this paper, we present the architecture of our implementation as well as a framework for automated negotiations, and describe a number of communication primitives which are used in the underlying negotiation protocol. A constraint satisfaction processor (CSP) is used to evaluate a negotiation proposal or counterproposal against the registered requirements and constraints of a client company. In case of a constraint violation, an event is posted to trigger the execution of negotiation strategic rules, which either automatically relax the violated constraint, ask for human intervention, invoke an application, or perform other remedial operations. An Event-Trigger-Rule (ETR) server is used to manage events, triggers, and rules. Negotiation strategic rules can be added or modified at run-time. A cost-benefit analysis component is used to perform quantitative analysis of alternatives. The use of negotiation servers to conduct automated negotiation has been demonstrated in the context of an integrated supply chain scenario. Received: 30 October 2000 / Accepted: 12 January 2001 Published online: 2 August 2001     

Graph visualization and navigation in information visualization: Asurvey

This is a survey on graph visualization and navigation techniques, as used in information visualization. Graphs appear in numerous applications such as Web browsing, state-transition diagrams, and data structures. The ability to visualize and to navigate in these potentially large, abstract graphs is often a crucial part of an application. Information visualization has specific requirements, which means that this survey approaches the results of traditional graph drawing from a different perspective     

Reconstruction from Sparsely Sampled Data by ART with Interpolated Rays

After a brief discussion of the algebraic reconstruction techniques (ART), we introduce the attenuation problem in positron emission tomography (PET). We anticipate that a generalization of ART, the so-called cyclic subgradient projection (CSP) method, may be useful for solving this problem. This, however, has not been successfully realized, due to the fact that data collected by our proposed stationary PET detector ring are too sparsely sampled. That this is, in fact, a major problem is demonstrated by showing that ordinary ART produces reconstructions with unacceptably strong artifacts even on perfect (no attenuation) data collected according to the PET geometry. We demonstrate that the source of this artifact is the sparse sampling, and we propose the use of interpolated rays to overcome the problem. This approach is successful, as is illustrated by showing reconstructions from sparsely sampled data by ART with interpolated rays.     

Boundary detection in multidimensions

The development of image processing algorithms for time-varying imagery and computerized tomography data calls for generalization of the concepts of adjacency, connectivity, boundary, etc., to three and four-dimensional discrete spaces. This paper defines these basic concepts in unified terminology and presents algorithms for a boundary detection task in multidimensional space. The performance of these algorithms is discussed with respect to theoretical maximum complexity, and is illustrated with simulated computerized tomography data.     

Linearized microring-loaded Mach-Zehnder modulator with RF gain

A linearized modulator based on the Mach-Zehnder interferometer (MZI) loaded with a second-order allpass microring resonator is proposed and analyzed. The device is shown to exhibit much smaller intermodulation distortion than standard Mach-Zehnder modulators, thus greatly enhancing the device dynamic range. Gain effect associated with the microring resonance results in a modulator transfer function with high slope efficiency and large RF gain. Moreover, combined with the use of a highly electrooptic polymer, the high slope efficiency allows for the possibility of realizing modulators with subvolt drive voltage. The detrimental effect of loss in the microring resonators on device performance is also investigated and a design approach to mitigate its effect is presented. The proposed modulator can be linearized to any arbitrary nth order by loading the MZI with a higher order allpass microring resonator.     

Factors and Pathways Modulating Endothelial Cell Senescence in Vascular Aging

Aging causes a progressive decline in the structure and function of organs. With advancing age, an accumulation of senescent endothelial cells (ECs) contributes to the risk of developing vascular dysfunction and cardiovascular diseases, including hypertension, diabetes, atherosclerosis, and neurodegeneration. Senescent ECs undergo phenotypic changes that alter the pattern of expressed proteins, as well as their morphologies and functions, and have been linked to vascular impairments, such as aortic stiffness, enhanced inflammation, and dysregulated vascular tone. Numerous molecules and pathways, including sirtuins, Klotho, RAAS, IGFBP, NRF2, and mTOR, have been implicated in promoting EC senescence. This review summarizes the molecular players and signaling pathways driving EC senescence and identifies targets with possible therapeutic value in age-related vascular diseases.     

The Effect of Leptin on the Blood Hormonal Profile (Cortisol,Insulin, Thyroid Hormones) of the Ewe in Acute Inflammation in Two Different Photoperiodical Conditions

As a day animal with sensitivity to inflammation similar to that of humans, the sheep may highly outperform the rodent model in inflammation studies. Additionally, seasonality makes sheep an interesting model in endocrinology research. Although there are studies concerning inflammation’s influence on leptin secretion and vice versa, a ewe model, with its possible ‘long-day leptin resistance’, is still not examined enough. The present study aimed to examine whether leptin may modulate an acute inflammation influence on plasma hormones in two photoperiodical conditions. The experiment was conducted on 48 ewes divided into four groups (control, lipopolysaccharide (LPS), leptin, LPS + leptin) during short and long days. Blood sampling started 1 hour before and continued 3 h after LPS/saline administration for further hormonal analysis. The results showed that the photoperiod is one of the main factors influencing the basal concentrations of several hormones with higher values of leptin, insulin and thyroid hormones during long days. Additionally, the acute inflammation effect on cortisol, insulin and thyroid hormones was photoperiod-dependent. The endotoxemia may also exert an influence on leptin concentration regardless of season. The effects of leptin alone on hormone blood concentrations are rather limited; however, leptin can modulate the LPS influence on insulin or thyroxine in a photoperiod-dependent way.     

Safety assessment of Lactobacillus strains: presence of putative risk factors in faecal, blood and probiotic isolates

The widespread use of immunosuppressive therapy and antimicrobial agents as well as novel probiotics without a long history of safe use has increased requirements for safety assessment of probiotic lactobacilli. In this study 44 faecal, 52 blood and 15 probiotic isolates (including 3 dairy strains) of Lactobacillus were assayed for their adhesion properties to extracellular matrix proteins and mucus, hemolysis, ability to avoid the induction of respiratory burst in peripheral blood mononucleocytes (PMN) and resistance to human serum. Among tested strains adhesion to collagen, fibrinogen and mucus was isolate-specific and no statistically significant differences were obtained between faecal, blood and probiotic isolates. However, blood isolates showed a trend for higher adhesion to mucus than probiotic strains (P=0.07). Probiotic strains induced lower respiratory burst in PMN when compared to the blood isolates (P<0.05). Moreover, there was a positive correlation between adhesion to collagen and induction of respiratory burst for faecal isolates (P<0.05). In the determination of serum resistance, probiotic strains showed a trend for lower sensitivity to human serum-mediated killing when compared to the faecal isolates (P=0.07). None of the measurable virulence factors were found to be present at statistically higher level in clinical blood isolates when compared to faecal and/or probiotic isolates indicating that these factors do not cause risk when safety of probiotics is considered. However, the significance of adhesion to mucus, low induction of respiratory burst in PMN and resistance to human serum-mediated killing may need further evaluation in experimental animal models and in epidemiological data.