Classical Performance Indicators Research Articles

Sensitivity of human-induced vibrations and comfort analysis to partially rigid STS joints in timber-to-timber composite floors

The study of floors vibration serviceability represents a well-known challenging task and has a critical role in comfort analysis, assessment and optimization of pedestrian systems in general. To this aim, several consolidated and/or simplified tools are available in the literature to address the most important aspects. In practice, however, most of assumptions for the analysis and verification are based on the use of rough mechanical models of joints and connections, which have indeed a primary role especially for composite floors. In this paper, the attention is given to timber-to-timber floors with inclined self-tapping screws (STS). A parametric Finite-Element (FE) numerical investigation is carried out by taking into account conventional walking features and a case-study timber-to-timber composite beam, well representative of a one-way wooden floor. A major advantage for structural and pedestrian modelling stages is taken from previous literature efforts, while large attention is spent for structural analysis and vibration serviceability assessment tasks, as a function of the STS mechanical parameters (first of all the secant stiffness). Comparative linear modal and non-linear time history analyses are carried out and addressed towards limit mechanical configurations for STS joints, in terms of vibration frequency considerations, as well as structural response and comfort assessment, based on classical performance indicators. The parametric numerical results are further discussed based on simplified methods provided by selected design standards. A critical analysis of major effects due to partial joint rigidity and floor performance classification is presented, both in terms of expected structural safety and comfort levels for similar systems.

In-Situ Quantification of the Ageing Dynamics in Lithium-Ion Cells up to Failure-Near Conditions

Implementing end-of-life (EOL) lithium-ion batteries from automotive applications in stationary energy storages is of utmost relevance for a sustainable handling of scarce resources. Beneficial from an economic and ecological perspective, such second-life applications urgently require a guarantee for safe operation. Unlike the state of health (SOH), defined by classical performance indicators such as capacity and voltage, the state of safety (SOS) of an aged battery cannot be assessed straightforward. Its determination requires a plethora of cells to be tested which is a particular challenge for new technologies with limited access to EOL batteries.For providing cells with a defined SOH at a reasonable timescale, we herein propose a novel method of greatly accelerating the ageing process of lithium-ion batteries. In a preliminary test series, lithium-ion NMC pouch cells are exposed to incrementally increasing temperatures, current rates and/or states of charge (SOC), until thermal runaway is induced. In this manner, the critical state in proximity to cell failure is spotted for individual and combined stress parameters. Based on this knowledge, cell-specific test parameters for heavily accelerated ageing are developed. In this protocol, electrical abuse conditions are defined by over/under charging and high current rates. Typically, the cells are cycled utilizing a depth of discharge above 100 %.The accelerated aging dynamics under these critical conditions are monitored by systematic capacity, open circuit voltage and electrochemical impedance spectroscopy (EIS) measurements. This enables a comparative assessment of the electrical behaviour, following conventional vs. heavily accelerated ageing. Such knowledge will in turn help to define the threshold to which cyclic ageing can be accelerated without changing the characteristic degradation mechanisms of lithium-ion batteries.

ECONOMIC INDICATORS USED IN THE DIAGNOSTIC ANALYSIS OF MULTINATIONAL COMPANIES: CASE STUDY FOR COMPANIES IN THE OIL AND BANKING FIELD

Purpose- The purpose of this research lies in the general objectives of the companies that determine the creation of added value. The efficiency in the use of the resources of the economic entity generates results. These can be analyzed and diagnosed in order to have an overview of the economic and financial state of the company. This scientific research aims to present the objective realities, the mechanism of formation and manifestation of economic and financial phenomena and processes, as well as the causal links between them in the case of ten multinational companies in the oil and banking sector. In the banking system, credibility is the essential element, the foundation of the relationship between the client and the bank when analyzing the granting of a loan. Gaining trust is achieved through a process of documentation and analysis of the client, which aims to evaluate as clearly as possible the patrimonial and financial situation, to recognize the quality of the services provided, the relationships with partners, the professionalism of the managers of companies. Methodology- This research was carried out having as documents the reports and information published by companies on their own web pages, as well as the annual reports published by each company on the Bucharest Stock Exchange website. 10 companies in the oil and banking field were selected, and the analysis period was between 2019-2022. The research methodology was both quantitative and qualitative. Findings- The results of the research highlighted the economic indicators used in the diagnostic analysis of multinational companies and how these entities evolved during the analyzed period. Conclusion- The importance of the diagnosed elements on a hierarchical scale may be different depending on the priority informational needs of the one who makes the diagnostic analysis. When this is done by a financial institution that makes an analysis of the creditworthiness of the client, in order to approve a credit, a solvency and liquidity diagnosis, the degree of indebtedness or cash flows, In the first place, the manager will pay attention to the efficiency of the use of the resources employed in the company’s economic circuit and to the results of the activity. An investor who wants to invest in a company will be particularly interested in the performance of the entity on the stock exchange and the profitability of the invested capital Value is the major criterion for assessing the company’s performance by shareholders. Classical performance indicators have the disadvantage of providing information about the company’s past performance, Without taking into account the cost of the invested capital, highlighting only the result of its use. If the one who makes the diagnosis is limited to studying only the classical indicators, he will be able to conclude that the entity achieves performance, but the results of the analysis will not present the actual reality because it does not create value and can even consume the existing one. Keywords: Diagnostic analysis, multinational companies, indebtedness degree, financial statements, cash flows JEL Codes: F23, G21, M41

Single body sensor for calibration of Spring-Mass-Damper parameters in biodynamic pedestrian modelling

For structural design and vibration monitoring purposes, several simplified equivalent-force models or more complex computational strategies are available to describe Human-Structure Interaction (HSI) phenomena on pedestrian systems, and in particular the vertical reaction forces induced by walking occupants. Among others, various Spring-Mass-Damper (SMD), Single Degree of Freedom (SDOF) biodynamic models of literature can be used to mechanically describe a single pedestrian in the form of equivalent body mass m, spring stiffness k and viscous damping coefficient c. Basically, existing SMD formulations are characterized by specific theoretical assumptions and (often complex) experimental methods for the calibration of m, k, c. Usually, SMD parameters can be optimally quantified when multiple sensors (on pedestrian’s body and on the structure) are used to capture motion features and the corresponding reaction force. In this paper, body accelerations of a pedestrian are tracked by means of a single Centre of Mass (CoM) sensor and are elaborated to derive basic input parameters for an alternative, newly optimized SMD model. Experimental registrations from a total of 30 random walks and more than 300 gaits (on rigid floor) are taken into account, and fitting expressions for m, k, c are proposed. The present SMD formulation (SMD-0) is validated towards a selection of literature proposals (SMD-1 to SMD-4), based on parametric numerical dynamic analyses (100 in total), which are carried out by taking into account various pacing frequencies (fp = 1.5–2 Hz the explored range) and four different pedestrian structures / floors (F#1 to F#4). The comparison of classical performance indicators for human-induced structural vibrations proves the efficiency and potential of current SMD-0 approach, and suggests further investigations in support of optimized protocols.

Quantifying and Numerically Representing Recharge and Flow Components in a Karstified Carbonate Aquifer.

Karstified carbonate aquifers are highly heterogeneous systems characterized by multiple recharge, flow, and discharge components. The quantification of the relative contribution of these components, as well as their numerical representation, remains a challenge. This paper identifies three recharge components in the time and frequency domain. While the analysis in the time domain follows traditional approaches, the analysis of the power spectrum allows frequencies associated with specific spectral coefficients and noise types to be distinguished more objectively. The analysis follows the presented hypothesis that the different frequency‐noise components are the result of aquifer heterogeneity transforming the random rainfall input into a sequence of non‐Gaussian signals. The distinct signals are then numerically represented in the context of a semidistributed pipe network model in order to simulate recharge, flow, and discharge of an Irish karst catchment more realistically. By linking the power spectra of the modeled recharge components with the spectra of the spring discharge, the information usually gained by classical performance indicators is significantly widened. The modeled spring discharge is well matched in the time and frequency domain, yet the different recharge dynamics explain the signal of the aquifer outlet in different noise domains across the spectrum. This study demonstrates the conjunctive use of frequency analysis in conceptualization of a hydrological system together with modeling and evaluation.

Multi-objective optimization of cost-effective and customer-centric closed-loop supply chain management model in T-environment

This article presents one real-life-based cost-effective and customer-centric closed-loop supply chain management model. The review of the existing literature identifies the classical performance indicators to any supply chain management model as the aggregate revenue, the customer satisfaction and the environmental concern. However, this review fails to find a single optimization-based supply chain management model that considers these three indicators, simultaneously. In this article, the proposed model maximizes the customer-satisfaction index and the aggregate revenue both under the environmental considerations via the reverse chain, whereas many existing studies took the reverse chain and the associated subsidies into account; this is the first mathematical model that optimizes the customer-satisfaction index, at the same time. This article employs the T-set that represents the inherent impreciseness to objective functions to the proposed model. The corresponding optimal values are superior than stipulated goals to both the objective functions in T-environment. The managerial insights extracted from sensitivity analysis of parameters suggest the managers to stabilize the environmental concern and the customer satisfaction, while ensuring the cost-effectiveness in real-life-based T-environment. Also, this analysis finds that the subsidy assists any supply chain to sustain, only if it is offered without any break and within the optimally determined bounds.

Using quantile regression forest to estimate uncertainty of digital soil mapping products

Digital Soil Mapping (DSM) products are simplified representations of more complex and partially unknown patterns of soil variations. Therefore, any prediction of a soil property that can be derived from these products has an irreducible uncertainty that needs to be mapped. The objective of this study was to compare the most current DSM method – Regression Kriging (RK) – with a new approach derived from RandomForest – Quantile Regression Forest (QRF) – in regard to their ability of predicting the uncertainties of GlobalSoilMap soil property grids. The comparison was performed for three soil properties, pH, organic carbon and clay content at 5–15cm depth in a 27,236km2 Mediterranean French region with sparse sets of measured soil profiles (1/13.5km2) and for a set of environmental covariates characterizing the relief, climate, geology and land use of the region. Apart from classical performance indicators, comparisons involved accuracy plots and the visual examinations of the uncertainty maps provided by the two methods.The results obtained for the three soil properties showed that QRF provided more accurate and more interpretable predicted patterns of uncertainty than RK did, while having similar performances in predicting soil properties. The use of QRF in operational DSM is therefore recommended, especially when spatial sampling of soil observations are too sparse for applying RK.

The aircraft ground routing problem: Analysis of industry punctuality indicators in a sustainable perspective

The ground routing problem consists in scheduling the movements of aircraft on the ground between runways and parking positions while respecting operational and safety requirements in the most efficient way. We present a Mixed Integer Programming (MIP) formulation for routing aircraft along a predetermined path. This formulation is generalized to allow several possible paths. Our model takes into account the classical performance indicators of the literature (the average taxi and completion times) but also the main punctuality indicators of the air traffic industry (the average delay and the on time performance). Then we investigate their relationship through experiments based on real data from Copenhagen Airport (CPH). We show that the industry punctuality indicators are in contradiction with the objective of reducing taxi times and therefore pollution emissions. We propose new indicators that are more sustainable, but also more relevant for stakeholders. We also show that alternate path cannot improve the performance indicators.

Analysis of Evaluation Indicators for Furrow Irrigation Using Opportunity Time

AbstractEvaluation procedures have been developed for effective design and management of irrigation systems. Furrow irrigation is one of the main types of applying water in the field. In the present study, a new procedure for field evaluation of water distribution in furrow irrigation is proposed. For this purpose, application efficiency (Ea), water requirement efficiency (Er), deep percolation (DP) and tail water ratio (TWR) have been introduced, based on the average of dimensionless infiltrated depth values in the four data groups. The relationships between coefficient of uniformity CU and distribution uniformity DU have been described by opportunity time values of each quarter and using the linear equation instead of the infiltration function. The proposed procedure was compared to existing methods by nine irrigation scenarios including three furrow length and three inflow rates. The results show that the evaluation indicators of furrow irrigation calculated with non‐dimensional parameters depend on opportunity time and new coefficients of the linear infiltration equation. Also, there was no observed significant difference on the suggested indice values and classical performance indicators. Copyright © 2015 John Wiley & Sons, Ltd.

Number Needed to Detect

Data mining algorithms are increasingly being used to support the process of signal detection and evaluation in pharmacovigilance. Published data mining exercises formulated within a screening paradigm typically calculate classical performance indicators such as sensitivity, specificity, predictive value and receiver operator characteristic curves. Extrapolating signal detection performance from these isolated data mining exercises to performance in real-world pharmacovigilance scenarios is complicated by numerous factors and some published exercises may promote an inappropriate and exclusive focus on only one aspect of performance. In this article, we discuss a variation on positive predictive value that we call the ‘number needed to detect’ that provides a simple and intuitive screening metric that might usefully supplement the usual presentations of data mining performance. We use a series of figures to demonstrate the nature and application of this metric, and selected adaptive variations. Even with simple and intuitive metrics, precisely quantifying the performance of contemporary data mining algorithms in pharmacovigilance is complicated by the complexity of the phenomena under surveillance and the manner in which the data are recorded in spontaneous reporting systems.

Drought in groundwater—drought distribution and performance indicators

In order to investigate how droughts are changed by the groundwater system and to analyse the performance of groundwater during drought, 10 time series of 1000 years of recharge and groundwater discharge were generated. The 10×1000 years of synthetic daily data were generated using Nearest Neighbour resampling based on 37 years of observed daily meteorological data. The root zone was simulated by a non-linear water balance model and the groundwater system by a linear reservoir model. The size and thus the response time of the reservoir was characterised by a reservoir coefficient. Subsequently, the deficit and duration of the droughts were derived from the time series of recharge and groundwater discharge using the threshold level approach. An analysis of the distribution of these droughts shows that for droughts with small return periods, the deficit in the groundwater discharge is smaller than in the recharge. For droughts with large return periods, the deficit in the groundwater discharge is larger than in the recharge. The performance of groundwater systems with respect to droughts was evaluated using three classical performance indicators (reliability, resilience and vulnerability), a combination of these three indicators (Loucks' sustainability index) and three newly defined overall performance indicators. The newly defined indicators combine the severity and frequency of the droughts, instead of analysing these separately in reliability and vulnerability. The performance is estimated for the groundwater recharge and for the discharge of groundwater systems with three different values of the reservoir coefficient. Of all the performance indicators used, one of the newly introduced overall performance indicators with a strong emphasis on droughts with a high return period appeared to characterise the groundwater droughts best. This indicator shows a more or less constant performance for low and medium high reservoir coefficients and an increasing performance for higher reservoir coefficients.

Transient Conduction in a Fin-Wall Assembly with Harmonic Excitation--Network Thermal Admittance

The classical performance indicators for extended surfaces, efficiency and effectiveness, cannot be used for the proper design of finned systems subject to time-dependent processes, such as heat exchangers or electric devices. Based on the network simulation method, a network model of a fin-wall assembly, whose admittance is identical to the thermal admittance of the system, has been designed for the whole system. A new fin performance indicator, output admittance, is proposed, and frequency analysis of the system is carried out. The simulated numerical response is rapidly obtained by running the network in the appropriate circuit resolution software. This method is especially useful for studying complex thermal transmission functions such as admittance, evaluating modulus, phase, and real and imaginary components of the thermal signal.