891 research outputs found

    Solutions for a class of iterated singular equations

    Full text link
    Some fundamental solutions of radial type for a class of iterated elliptic singular equations including the iterated Euler equation are given.Comment: 7 page

    Quantifying the value of buyer-vendor coordination: Analytical and numerical results under different replenishment cost structures

    Get PDF
    Cataloged from PDF version of article.Despite a growing interest in channel coordination, no detailed analytical or numerical results measuring its impact on system performance have been reported in the literature. Hence, this paper aims to develop analytical and numerical results documenting the system-wide cost improvement rates that are due to coordination. To this end, we revisit the classical buyer–vendor coordination problem introduced by Goyal [S.K. Goyal, An integrated inventory model for a single-supplier single-customer problem. International Journal of Production Research 15 (1976) 107–111] and extended by Toptal et al. [A. Toptal, S. C¾ etinkaya, C.-Y. Lee, The buyer–vendor coordination problem: modeling inbound and outbound cargo capacity and costs, IIE Transactions on Logistics and Scheduling 35 (2003) 987–1002] to consider generalized replenishment costs under centralized decision making. We analyze (i) how the counterpart centralized and decentralized solutions differ from each other, (ii) under what circumstances their implications are similar, and (iii) the effect of generalized replenishment costs on the system-wide cost improvement rates that are due to coordination. First, considering Goyal’s basic setting, we show that the improvement rate depends on cost parameters. We characterize this dependency analytically, develop analytical bounds on the improvement rate, and identify the problem instances in which considerable savings can be achieved through coordination. Next, we analyze Toptal et al.’s [A. Toptal, S. C¾ etinkaya, C.-Y. Lee, The buyer–vendor coordination problem: modeling inbound and outbound cargo capacity and costs, IIE Transactions on Logistics and Scheduling 35 (2003) 987–1002] extended setting that considers generalized replenishment costs representing inbound and outbound transportation considerations, and we present detailed numerical results quantifying the value of coordination. We report significant improvement rates with and without explicit transportation considerations, and we present numerical evidence which suggests that larger rates are more likely in the former case. 2006 Elsevier B.V. All rights reserved

    Model Continuity in Discrete Event Simulation: A Framework for Model-Driven Development of Simulation Models.

    Get PDF
    Most of the well known modeling and simulation methodologies state the importance of conceptual modeling in simulation studies and they suggest the use of conceptual models during the simulation model development process. However, only a limited number of methodologies refers to howto move from a conceptual model to an executable simulation model. Besides, existing modeling and simulation methodologies do not typically provide a formal method for model transformations between the models in different stages of the development process. Hence, in the current M&S practice, model continuity is usually not fulfilled. In this article, a model driven development framework for modeling and simulation is in order to bridge the gap between different stages of a simulation study and to obtain model continuity. The applicability of the framework is illustrated with a prototype modeling environment and a case study in the discrete event simulation domain

    unreinforced masonry buildings

    Get PDF
    A recent earthquake of M=4.9 occurred on 29 October 2007 in C, ameli, Denizli, which is located in a seismically active region at southwest Anatolia, Turkey. It has caused extensive damages at unreinforced masonry buildings like many other cases observed in Turkey during other previous earthquakes. Most of the damaged structures were non-engineered, seismically deficient, unreinforced masonry buildings. This paper presents a site survey of these damaged buildings. In addition to typical masonry damages, some infrequent, event-specific damages were also observed. Reasons for the relatively wide spread damages considering the magnitude of the event are discussed in the paper

    A Process Model for Component-Based Model-Driven Software Development

    Get PDF
    Developing high quality, reliable and on time software systems is challenging due to the increasing size and complexity of these systems. Traditional software development approaches are not suitable for dealing with such challenges, so several approaches have been introduced to increase the productivity and reusability during the software development process. Two of these approaches are Component-Based Software Engineering (CBSE) and Model-Driven Software Development (MDD) which focus on reusing pre-developed code and using models throughout the development process respectively. There are many research studies that show the benefits of using software components and model-driven approaches. However, in many cases the development process is either ad-hoc or not well-defined. This paper proposes a new software development process model that merges CBSE and MDD principles to facilitate software development. The model is successfully tested by applying it to the development of an e-learning system as an exemplar case stud

    R Markdown: Integrating A Reproducible Analysis Tool into Introductory Statistics

    Get PDF
    Nolan and Temple Lang argue that “the ability to express statistical computations is an es- sential skill.” A key related capacity is the ability to conduct and present data analysis in a way that another person can understand and replicate. The copy-and-paste workflow that is an artifact of antiquated user-interface design makes reproducibility of statistical analysis more difficult, especially as data become increasingly complex and statistical methods become increasingly sophisticated. R Markdown is a new technology that makes creating fully-reproducible statistical analysis simple and painless. It provides a solution suitable not only for cutting edge research, but also for use in an introductory statistics course. We present experiential and statistical evidence that R Markdown can be used effectively in introductory statistics courses, and discuss its role in the rapidly-changing world of statistical computation

    Single Production of Vectorlike Y Quarks at the HL-LHC

    Full text link
    We study single production of exotic vectorlike YY quark with electric charge ∣QY∣=4/3|Q_{Y}|=4/3 and its subsequent decay at the High Luminosity LHC (HL-LHC). Most of the vector like quark (VLQ) decays have the electroweak WW bosons in the intermediate state. Besides their direct productions singly or pairs, the WW-bosons are involved in decay chains as a result of the decay of a top quark which contributes to the background. This is particularly the case since vectorlike YY quark, which is estimated to be produced with a high cross-section, can only decay via a WW boson and a down type quark (d,s,bd,s,b). We calculate the cross sections of signal (for different couplings and mass values) and relevant Standard Model (SM) backgrounds. After a fast simulation of signal and background events, estimations of the sensitivity to the parameters (mass range 1000-2500 GeV for coupling value ÎșY=0.5\kappa_{Y}=0.5, and mass range 500-2000 GeV for coupling values ÎșY=0.3\kappa_{Y}=0.3 and ÎșY=0.15\kappa_{Y}=0.15) have been presented at the HL-LHC with center of mass energy s=14\sqrt{s}=14 TeV and integrated luminosity projections of 300 fb−1^{-1}, 1000 fb−1^{-1} and 3000 fb−1^{-1}.Comment: 14 pages, 21 figure

    Genotypic identification and technological characterization of lactic acid bacteria isolated from traditional Turkish Kargi tulum cheese

    Get PDF
    Kargi tulum cheese is an artisanal cheese produced through the spontaneous fermentation of raw milk ripened inside a goat-skin bag. The objective of this study was to characterize the dominant species of natural lactic acid bacteria (LAB) found in Kargi tulum cheese. Some technologically important properties of LAB isolates were also determined. Seven samples of cheese of different levels of ripeness were taken from local producers and 97 isolates were obtained from these samples. Non-spore forming, Gram-positive, catalase- and oxidase-negative isolates were assessed as LAB. Based on genotypic characterization, the dominant LAB were identified as Lactobacillus paracasei (43.3%), Lactobacillus plantarum (23.7%), Enterococcus durans (6.2%), Streptococcus thermophilus (6.2%), Lactobacillus brevis (5.2%), Enterococcus faecium (5.2%), Lactobacillus fermentum (4.1%) and Lactobacillus pentosus (1%). Homofermentative strains such as L. paracasei, L. plantarum, S. thermophilus; E. durans and E. faecium were selected as probable starter cultures. These strains were tolerant to 6.5% salt. They are also characterized by acidification ability (from pH = 6.6 to 4.7 to 6.0, in 6 to 8 h), low proteinase and high peptidase, esterase, esterase-lipase, ÎČ-galactosidase and ÎČ- glucosidase activities. They also produce diacetyl and H2O2.Key words: Lactic acid bacteria, genotypic characterization, technological characterization, tulum cheese

    Model-based PI design for irrigation canals with faulty communication networks

    Get PDF
    A PI design method for faulty networks is provided based on Linear Matrix Inequalities (LMIs). Feedback controllers for irrigation canals are designed based on LMIs, but sparsity constraints are also imposed to make zero the feedback control law elements not corresponding to the tuning PI parameters. Therefore, the design method is halfway between a PI controller and an optimal feedback control law, also providing stability guarantees up to a maximum probability of packet losses. The objective of the downstream controller is to maintain the water levels upstream from each downstream check structure of each canal pool, while gravity-offtake gates satisfy downstream water demands. The proposed approach is tested using the irrigation system of ASCE Test Canal 1 and compared with other tuning methods via simulation. Our results show that the design method can be a useful tool when dealing with control systems under faulty networks

    Effects of Nigella sativa seeds and certain species of fungi extracts on number and activation of dural mast cells in rats

    Get PDF
    In this study, we aimed to investigate the effects of Nigella sativa seeds and certain species of fungi extracts on the number and degranulation states of dural mast cells in rats. Rats were fed ad libitum with normal tap water or tap water with extract of N. sativa seed, Ramaria condensata, Lactarius salmonicolor, Lactarius piperatus, and Tricholoma terreum for 3 days. Mast cells in dura mater were counted and evaluated in terms of granulation and degranulation states. Compound 48/80, a mast cell degranulating agent, and T. terreum significantly increased the percent of degranulated mast cells in dura mater, respectively (p < 0.01 and p < 0.05). Moreover, T. terreum causes a significant increase in the total number of mast cells (p < 0.05). N. sativa significantly inhibited mast cell degranulation induced by both the compound 48/80 and T. terreum (p < 0.05), and significantly decreased the mast cell numbers increased by T. terreum (p < 0.05). Our results suggested that T. terreum following ingestion can contribute to headaches like migraine via dural mast cell degranulation and N. sativa may be able to exert analgesic and anti-inflammatory effects by stabilizing dural mast cells. However, investigation is needed to determine the ingredients of N. sativa that may be responsible for these beneficial effects
    • 

    corecore