This paper presents a machine learning (ML) approach to wind turbine (WT) lightning incidence analysis in complex terrain, based on the information obtained from a lightning location system (LLS). A ...particular ML model of the WTs lightning incidence is developed, using Bayesian statistical learning and Gaussian process regression, and trained on the actual LLS data. The model is developed around a known proposition that the lightning strike frequency data are emanating from a Poisson stochastic process. It further makes use of an attractive radius concept of lightning attachment, employs a sophisticated analysis of the WT effective height—which leverages terrain elevation data—and introduces spatial autocorrelation of lightning strikes. It provides a probabilistic risk assessment of WT lightning damage, along with a statistical measures of the associated monetized financial losses. Proposed ML model benefits from the Bayesian ability to quantify uncertainty of model parameters, and employ hierarchical model structure that informs model parameters through the mutual higher-level hyperpriors. Proposed model enables both investors and insurance companies to asses risks associated with lightning incidence to WTs, considering historical LLS data and future wind farm installation locations.
DISK ARRAY SIMULATION MODEL DEVELOPMENT VICKOVIC, L; CELAR, S; MUDNIC, E
International journal of simulation modelling,
03/2011, Letnik:
10, Številka:
1
Journal Article
Recenzirano
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This paper presents a detailed development process of dynamic, discrete event simulation model for disk array. It combines a hierarchical decomposition with the "bottom up" approach. This way, at the ...beginning, the focus is set on the elementary storage component--a single disk drive. Once when functional simulation model for disk drive has been achieved it is used as a basic storage element for disk array model development. Further on, it is explored how to simulate different interfaces inside disk array, toward underlying disks. The difference in throughput produced by developed model and measurements is from 1.5-3.16 % for writing and from 2.5-2.8 % for reading, depending on interface type. However, such results are limited on workload imposed by the requirements of the ALICE transient storage system, or more precisely, sequential storing and reading of large data files. (Received in August 2010, accepted in December 2010. This paper was with the authors 2 months for 1 revision.) Key Words: Discrete-Event Simulation, Disk Array Simulation, Disk Simulation, Disk Cache Model
In the early phase of software project, there are little measurable software artifacts as well as little time for measurements. Reliable software size estimation in such early project phase ...significantly influence estimation reliability of other project parameters and overall project success rate. This paper presents evolutionary method for estimation objects development based on historical measurement data. Estimation objects recognized from the measurement data in three steps are classified according their attributes into hierarchy dimensions. Estimation objects are enterprise native and easy for use in early software size estimation. Also, in the paper case study results from the SME applying Function Points for Functional Size Measurement (FSM) are described but the method is independent of FSM or functional size unit.
Function point metrics are widely used and the most effective yet performed functional sizing methods (FSM). Organizations that successfully use that measurement methods for several years can build ...their own software estimating methods. Using such estimating methods it is possible to estimate the software size and project effort at the early project beginning and thus reduce the high project costs. In this paper we present the software estimation method based on the Mk II Function Points Analysis 1.3.1 Unadjusted that is used in Croatian software development middle large company. The method was applied on the ERP implementation project in the Financial Agency (Croatia). The final counting (7.560 FP) showed an acceptable increase of estimated function points (6.773 FP) from 11,6%.
Connecting distributed generation to a distribution network affects the load flows in the network, resulting in the redistribution of load flows in the network and thereby changing the amount of ...active energy losses. At a given moment, depending upon the network consumption and the power injected from a wind power plant into the network, the active power losses can be higher or lower than they were before the wind power plant was connected. However, the aggregate annual energy losses, rather than instantaneous active power losses, are of significance. Therefore, a methodology has been developed for calculating the annual active energy losses in a distribution network in the case of a distributed generation connection, assuming the known chronological consumption and production curves. The corresponding calculations have been performed for an existing distribution network and a wind power plant scheduled to be connected to it.
Voltage dips and short interruptions are mainly caused by the short circuit in transmission and distribution network. In this paper it is given the calculation of short circuits influence zone in ...transmission network affecting the depth of voltage dip in the examined node. There is also given the calculation of voltage dip propagation inside the examined industrial facility for the case of one-phase short circuit. The check of the influence zone and voltage dip propagation is experimental confirmed by measurements made in one-month period.
Priključak distribuiranih izvora energije na distribucijsku mrežu, između ostalih utjecaja, ima za posljedicu preraspodjelu tokova snaga u mreži, a time i promjenu iznosa gubitaka radne energije. U ...određenom trenutku, ovisno o potrošnji u mreži i snazi koju u mrežu injektira vjetroelektrana, gubici radne snage mogu biti veći ili manji u odnosu na stanje bez priključene elektrane. Međutim, trenutačna vrijednost gubitaka radne snage nije bitna, već prvenstveno ukupni gubici radne energije na godišnjoj razini. Zbog toga je u radu razrađena metodologija proračuna godišnjih gubitaka radne energije u distribucijskoj mreži u uvjetima priključenog distribuiranog izvora, pri čemu se polazi od poznatih kronoloških krivulja opterećenja i proizvodnje. Odgovarajući proračuni su izvršeni na primjeru realne distribucijske mreže i vjetroelektrane koja se planira priključiti na nju.
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