检索结果-南通市图书馆

ESTIMATING CROSS-TRAINING CALL CENTER CAPACITY THROUGH SIMULATION

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science and Systems Engineering 2016年第4期25卷 448-468页

作者： David A. munoz Nathaniel D. Bastian Department of Industrial and Manufacturing Engineering The Pennsylvania State University

Call centers have grown world-wide during the past decade. One of the most important aspects considered by call center managers is the optimization of its operators, which implies covering the highly variable demand and f＇mding an efficient way to assign people to certain shifts in order to achieve a desirable service level and abandonment rate. Another challenge is determining which system setup is appropriate for the specific call center. Should we have a single-skill call center or multi-skill call center？ If we do have the latter, how many multi-skill agents should we have on staff？. In this case study, we generate and analyze discrete-event systems simulation-optimization models to test the behavior of a real-world call center under the actual configuration and under different levels of cross-training. The model results help call center managers by： 1） determining the optimal number of operators needed for different staff configtmations in order to achieve the targets for service level and abandonment; 2） providing information about the trade-off between the key measurements in the call center; and 3） providing useful information about the number of operators needed and used for each hour of operation to estimate the number of four-hour shifts required to achieve the performance targets. Our experimental f＇mdings from this case study suggest that a bi-skill call center is economically better in the long-rtm compared to a full-skill or single-skill call center. This case study augments the call center body of knowledge by providing additional managerial insights for the operations management community.

关键词： Call centers cross-training discrete-event systems simulation simulation optimization service operations service systems

Machine learning assisted derivation of minimal low-energy models for metallic magnets

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

npj Computational Materials 2023年第1期9卷 353-364页

作者： Vikram Sharma Zhentao Wang cristian D.Batista Department of Physics and Astronomy The University of TennesseeKnoxvilleTN 37996USA School of Physics and Astronomy University of MinnesotaMinneapolisMN 55455USA Quantum Condensed Matter Division and Shull-Wollan Center Oak Ridge National LaboratoryOak RidgeTN 37831USA Present address:Center for Correlated Matter and School of Physics Zhejiang UniversityHangzhou 310058China

We consider the problem of extracting a low-energy spin Hamiltonian from a triangular Kondo Lattice Model(KLM).The non-analytic dependence of the effective spin-spin interactions on the Kondo exchange excludes the use of perturbation theory beyond the second *** then introduce a Machine Learning(ML)assisted protocol to extract effective two-and four-spin *** resulting spin model reproduces the phase diagram of the original KLM as a function of magnetic field and single-ion anisotropy and reveals the effective four-spin interactions that stabilize the field-induced skyrmion crystal ***,this model enables the computation of static and dynamical properties with a much lower numerical cost relative to the original KLM.A comparison of the dynamical spin structure factor in the fully polarized phase computed with both models reveals a good agreement for the magnon dispersion even though this information was not included in the training data set.

关键词： Kondo dynamical derivation

Bi-normalized response spectra and seismic intensity in Bucharest for 1986 and 1990 Vrancea seismic events

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2014年第1期13卷 125-135页

作者： Florin Pavel Radu Vacareanu cristian Neagu Andrei Pricopie Department of Reinforced Concrete Structures Technical University of Civil Engineering BucharestRomania Department of Strength of Materials Bridges and TunnelsTechnical University of Civil Engineering BucharestRomania

The Vrancea subcrustal earthquakes of August 30,1986 and May 30,1990 are the two most recent seismic events that have occurred in Romania with moment magnitudes M W ≥ *** spectral analysis of the strong ground motions recorded in Bucharest reveals that despite small differences in magnitude between the 1986 and 1990 earthquakes,their frequency contents are very different,sometimes even *** main focus of this study is to conduct a comparative analysis of the response spectra in terms of the bi-normalized response spectra(BNRS) proposed by Xu and Xie(2004 and 2007) for strong ground motions recorded in Bucharest during these two seismic *** mean absolute acceleration and relative velocity response spectra for the two earthquakes are discussed and ***,the mean bi-normalized absolute acceleration and normalized relative velocity response spectra with respect to the control period T C are computed for the ground motions recorded in Bucharest in 1986 and *** predominant period T P is also used in this study for the normalization of the spectral period ***,the methodology proposed by Martinez-Perreira and Bommer(1998) is applied in order to estimate the seismic intensity of the two *** results are discussed and several conclusions regarding the possibility of using the bi-normalized response spectra(BNRS) are given.

关键词： response spectra bi-normalized response spectra dynamic amplifi cation factor control period damage potential parameters

Jet CAT P80 Thermal Analyses and Performance Assessment Using Different Fuels Types

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2018年第4期27卷 389-393页

作者： Grigore CICAN Adina TOMA cristian PUSCASU Razvan CATANA Politehnica University of Bucharest Faculty of Aerospace Engineering 1-7 Polizu Street 011061 Bucharest 1 Romania National Research and Development Institute for Gas Turbines - COMOTI 220D Iuliu Maniu Ave Bucharest 6 Romania

The micro gas turbine propulsion systems represent a good choice for the unmanned aerial vehicles(UAVs). The present work monitors the engine parameters, correlating them with other important engine instrumentation data. The aim of this research was to study the operation of the Jet CAT using various types of fuels under various operating conditions: normal acceleration and sudden acceleration. The measured parameters were monitored under different conditions:(A) Engine operation at two different ambient temperatures – outdoor at 0oC and inside at 19oC; and(B) Using 4 fuel types: kerosene, diesel fuel, kerosene with 5% gasoline and kerosene with 10% gasoline. The relevance of this work is given by the fact that a detailed analysis is performed for the idle regime. The paper will present the detailed test plan used and the most relevant charts with the obtained results for: start time, force, temperature before turbine, fuel flow, depending on micro turbo engine speed.

关键词： Jet CAT P80 fuel performance testing thermal analysis

Field report:Sailing around the exhumed roots of the Mesozoic Patagonian paleo-accretionary wedge(Diego de Almagro Island,Chile)

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2018年第5期9卷 1591-1594页

作者： Samuel Angiboust Jesus munoz Institut de Physique du Globe de Paris Sorbonne Paris CitéUniversity Paris DiderotCNRSF-75005ParisFrance GFZ German Research Centre for Geosciences D-14473PotsdamGermany Carrera de Geología Universidad Andres BelloSazie2119SantiagoChile

We undertook a boat expedition to explore the geological framework of a very remote, lesser-known island, in the Chilean Patagonia: the Diego de Almagro Island(latitude S51°330'). This uninhabited, ca.400 km^2 Island is one of the very rare exposures of the Mesozoic accretionary subduction complex along the Chilean margin. Unstable weather, strong winds, steep topography, and very dense vegetation make an on-land mission difficult. Careful preparation based on high-resolution satellite images is advised to optimize shore access and minimize risks of injury. Despite a relatively important degree of regional reequilibration of metamorphic assemblages due to sluggish exhumation through the forearc crust, our results have shown that the island is composed of a nappe stack of ocean-floor derived slivers of metasedimentary units that exhibit very different pressure-temperature-time paths during burial by subduction under the Chilean margin and subsequent exhumation. These rocks are witness to a complex thermal evolution of the subduction zone between Jurassic and Cretaceous times from granulite facies to blueschist facies conditions as well as multiple episodes of accretion at ca. 35 -40 km in depth for almost100 Ma over the Mesozoic era.

关键词： Patagonia Accretionary wedge Blueschists Subduction Chile

A novel botnet attack detection for IoT networks based on communication graphs

在线全文

学校读者我要写书评

暂无评论

Cybersecurity 2024年第4期7卷 19-35页

作者： David Concejal munoz Antonio del-Corte Valiente Inetum Espana S.A. C/Maria de Portugal9-11Building 128050 MadridSpain Department of Computer Engineering Polytechnic SchoolUniversity of AlcalaMadrid-Barcelona Road Km 33.6.Alcala de Henares28871 MadridSpain

Intrusion detection systems have been proposed for the detection of botnet *** types of centralized or distributed cloud-based machine learning and deep learning models have been ***,the emergence of the Internet of Things(loT)has brought about a huge increase in connected devices,necessitating a different *** this paper,we propose to perform detection on IoT-edge *** suggested architecture includes an anomaly intrusion detection system in the application layer of IoT-edge devices,arranged in software-defined ***-edge devices request information from the software-defined networks controller about their own behaviour in the *** behaviour is represented by communication graphs and is novel for IoT *** representation better characterizes the behaviour of the device than the traditional analysis of network traffc,with a lower volume of *** attack scenarios are simulated with the IoT-23 *** results show that attacks are detected with high accuracy using a deep learning model with low device memory requirements and significant storage reduction for training.

关键词： Autoencoders Communication graphs Cyberattacks Internet of Things

Multi-planet extrasolar systems-detection and dynamics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2012年第8期12卷 1044-1080页

作者： cristian Beaug Sylvio Ferraz-Mello Tatiana A.Michtchenko Instituto de Astronomía Teóricay Experimental Observatório Astronómico de CórdobaUniversidad de CórdobaArgentina Instituto de Astronomia Geofísica e Cie ncias AtmosfricasUniversidade de So PauloBrasil

20 years after the discovery of the first planets outside our solar system, the current exoplanetary population includes more than 700 confirmed planets around main sequence stars. Approximately 50% belong to multiple-planet systems in very diverse dynamical configurations, from two-planet hierarchical systems to multiple resonances that could only have been attained as the consequence of a smooth large- scale orbital migration. The first part of this paper reviews the main detection tech- niques employed for the detection and orbital characterization of multiple-planet sys- tems, from the （now） classical radial velocity （RV） method to the use of transit time variations （TTV） for the identification of additional planetary bodies orbiting the same star. In the second part we discuss the dynamical evolution of multi-planet systems due to their mutual gravitational interactions. We analyze possible modes of motion for hi- erarchical, secular or resonant configurations, and what stability criteria can be defined in each case. In some cases, the dynamics can be well approximated by simple ana- lytical expressions for the Hamiltonian function, while other configurations can only be studied with semi-analytical or numerical tools. In particular, we show how mean- motion resonances can generate complex structures in the phase space where different libration islands and circulation domains are separated by chaotic layers. In all cases we use real exoplanetary systems as working examples.

关键词： planetary systems -- planetary systems: formation

Optimal Feeder Routing in Urban Distribution Networks Planning with Layout Constraints and Losses

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2020年第5期8卷 1005-1014页

作者： Alessandro Bosisio Alberto Berizzi Edoardo Amaldi cristian Bovo Xu Andy Sun IEEE Department of Energy Politecnico di MilanoVia La Masa3420165 MilanoItaly Department of Electronics Informationand BioengineeringPolitecnico di MilanoVia Ponzio34/520133 MilanoItaly H.Milton Stewart School Georgia Institute of Technology775 Ferst DriveAtlanta GA 30332USA

We address the problem of optimally re-routing the feeders of urban distribution network in Milano,Italy,which presents some peculiarities and significant design *** has two separate medium-voltage(MV)distribution networks,previously operated by two different utilities,which grew up independently and *** results in a system layout which is inefficient,redundant,and difficult to manage due to different operating *** current utility UNARETI,which is in charge of the overall distribution system,aims at optimally integrating the two MV distribution networks and moving to a new specific layout that offers advantages from the perspectives of reliability and *** present a mixed-integer programming(MIP)approach for the design of a new network configuration satisfying the so-called 2-step ladder layout required by the *** model accounts for the main electrical constraints such as power flow equations,thermal limits of high-voltage(HV)/MV substation transformers,line thermal limits,and the maximum number of customers per *** power losses are taken into account via a quadratic formulation and a piecewise linear *** tests on a small-scale system and on a part of the Milano distribution network are reported.

关键词： Mixed-integer programming(MIP) graph theory power system planning urban distribution network feeder routing optimization

A comparative study for the performance of encased granular columns

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2019年第2期11卷 379-388页

作者： Iman Hosseinpour cristian Soriano Marcio S.S.Almeida Department of Civil Engineering Faculty of EngineeringThe University of Guilan Graduate School in Research and Engineering (COPPE) Federal University of Rio de Janeiro (UFRJ)

This paper describes a three-dimensional(3D) numerical analysis of a test embankment on geotextileencased columns(GECs), in comparison with two-dimensional(2D) axisymmetric and plane strain analyses. The 3D numerical analysis was performed considering a rectangular strip under the embankment centerline. The 2D analysis was also carried out using axisymmetric unit cell and plane strain *** results indicated that the adopted 3D strip model represented well the measured deformations and pore pressure evolution during embankment construction and post-contraction *** the unit cell model, both plane strain and 3D analyses could properly determine the settlement profile along the embankment base as well as the profile of the horizontal soil deformation beneath the embankment toes. The plane strain analysis, however, was not able to compute the geotextile ring force which might be simply calculated using the axisymmetric unit cell approach. The paper also showed that, due to horizontal boundary fixities applied to the embankment borders, the unit cell model clearly underestimated the tension developed in the basal geogrid.

关键词： Soft soil Embankment Encased columns Geosynthetic Numerical analysis