Search results for "Frequency analysis"

Bone implant sockets made using three different procedures: a stability study in dogs

2012

Objective: This study compared the effects of three different methods of preparing bone implant sockets (drilling, osteotomes, and piezoelectric device) on osseointegration using resonance frequency analysis (RFA). Study Design: An experimental prospective study was designed. Material and Methods: Ten adult beagle dogs were studied. After 5 weeks, 23 out of 28 initially placed implants in the iliac crest were evaluated, comparing these three different procedures of bone implant socket. Student’s t-test (paired, two-tailed) was used to reveal differences among the three groups at each time point (SPSS 16.0, IL, USA). Results: After a 5-week healing period, the implants placed in sockets that…

The weight of the flood‐of‐record in flood frequency analysis

2018

Use of L-moments approach for regional flood frequency analysis in Sicily, Italy

2008

Extremely great floods are among environmental events with the most disastrous consequences for the entire world. Estimates of their return periods and design values are of great importance in hydrologic modeling, engineering practice for water resources and reservoirs design and management, planning for weather-related emergencies, etc. Regional flood frequency analysis resolves the problem of estimating the extreme flood events for catchments having short data records or ungauged catchments. This paper analyzes annual maximum peak flood discharge data recorded from more than 50 stream flow gauging sites in Sicily, Italy, in order to derive regional flood frequency curves. First these data…

Annual runoff regional frequency analysis in Sicily

2009

Abstract This paper performs annual runoff frequency analysis in Sicily, Italy using the index runoff method. Homogeneous regions, not necessarily defined by geographical boundaries but sharing common features from a morphologic and climatic standpoint, have been identified. For each region a single probability distribution function can be fitted to the available annual runoff data scaled by the index runoff. Starting from an initial dataset of 105 hydrometric stations, 57 stations have been selected using heuristic criteria associated with the Hosking and Wallis’s discordancy measure. The Mantel tests have been then applied to find out the physical and morphological parameters best correla…

Estimation of flood inundation probabilities using global hazard indexes based on hydrodynamic variables

2008

In this paper a new procedure to derive flood hazard maps incorporating uncertainty concepts is presented. The layout of the procedure can be resumed as follows: (1) stochastic input of flood hydrograph modelled through a direct Monte-Carlo simulation based on flood recorded data. Generation of flood peaks and flow volumes has been obtained via copulas, which describe and model the correlation between these two variables independently of the marginal laws involved. The shape of hydrograph has been generated on the basis of a historical significant flood events, via cluster analysis; (2) modelling of flood propagation using a hyperbolic finite element model based on the DSV equations; (3) de…

Multi-year drought frequency analysis at multiple sites by operational hydrology - A comparison of methods

2006

Abstract This paper compares two generators of yearly water availabilities from sources located at multiple sites with regard to their ability to reproduce the characteristics of historical critical periods and to provide reliable results in terms of the return period of critical sequences of different length. The two models are a novel multi-site Markov mixture model explicitly accounting for drought occurrences and a multivariate ARMA. In the case of the multisite Markov mixture model parameter estimation is limited to a search in the parameter space guided by the value of parameter λ to show the sensitivity of the model to this parameter. Application to two of the longest time series of …

Establishing a soil loss threshold for limiting rilling

2015

In this paper a frequency analysis of event soil loss measurements collected in the period 1999–2012 at the microplots and plots of the Sparacia Experimental Area in Sicily, southern Italy, was developed. The analysis was carried out using the annual maximum soil loss measurements normalized by the mean soil loss measured at a given temporal and spatial scale. The empirical frequency distribution of the normalized variable was well fitted by two Gumbel’s theoretical probability distributions discriminated by a value of the normalized variable equal to 2. This last value discriminates between the relatively low and frequent values of the normalized variable and the high and rare ones. The an…

Retoriskie līdzekļi IKEA satura mārketinga tekstos

2018

Mūsdienu patērētāji dod priekšroku zīmoliem, kuru vērtību sistēma ir tāda pat kā šo patērētāju. Viņi atzīst par labāku individualizētu pieeju sev, izklaidējošu saturu, kurā dalīties ar saviem kontaktiem, daudz vizuālās informācijas un emocionālus stāstus. Tāpēc bakalaura darba mērķis bija izpētīt, cik plaši IKEA izmanto retoriskos līdzekļus satura mārketinga tekstos IKEA tīmekļa lapā Apvienotajā Karalistē, lai izraisītu pozitīvu klientu atbildes reakciju. Tā kā IKEA tiek uzskatīts par satura mārketinga gigantu no IKEA Apvienotās Karalistes mājaslapas tika izvēlēti 20 raksti, kuri tika analizēti. Pētījuma rezultāti parādīja to, ka retoriskie līdzekļi tika izmantoti 83 reizes. Visizplatītākās…

Relation between bone density and primary implant stability

2010

Aims: This study aims to relate bone density in Hounsfield units (Hu) with the primary implant stability measured by insertion torque (Ncm) and resonance frequency analysis (ISQ). Materials and Methods: Ten patients were included in this study. A total of 54 implant sites were provided from 10 computerized tomography scans. The computerized tomography scan was used for the preoperative evaluation of bone density for each patient. The bone mean density around planned implants was determined with Physioplanet TM software. Bone quality according resistance to drilling, insertion torque and resonance frequency measurements were recorded. Results: A statistically significant relationship was obs…

Influence of cortical bone and implant design in the primary stability of dental implants measured by two different devices of resonance frequency an…

2020

Background This study aimed to evaluate the effect of the implant design and the presence of cortical bone in the primary stability, as well as analyze the differences between the stability measurements obtained by two different resonance frequency analysis (RFA) devices. Material and methods A total of 80 Klockner implants of two different models [40 Essential Cone implants (group A) and 40 Vega implants (group B)] were used. The implants were placed in two polyurethane blocks that simulated the mechanical properties of the maxillary bone. One block featured a layer of cortical bone that was absent from the other block. The primary stability of all implants was measured by insertion torque…