Floor Performance Research Articles

PRESCRIPTIVE MAINTENANCE SYNCHRONIZED TO THE CHARACTERISTICS OF INDUSTRY 5.0: A THEORETICAL DISCUSSION

This article aims to examine and understand the current scope of Prescriptive Maintenance integrated with the human-centric characteristics of Industry 5.0. Therefore, the main research question is the following: “In the view of the managers of the companies visited, located in the Southeast Region of Brazil, what are the main technical and administrative difficulties that companies encounter in successfully implementing proactive combinations on the factory floor, such as Prescriptive Maintenance integrated with the characteristics of Industry 5.0”?. The evolution of industrial processes in recent decades and the advent of Industry 4.0 integrated with human-centered characteristics have placed maintenance as one of the protagonists of industrial processes. In a scenario where automation and humans are gaining more and more space, the future of industries lies in Prescriptive Maintenance. To achieve the objective of the article, professional experiences from participation in congresses, seminars and technical visits to several factories located in the Southeast Region of Brazil are used. In data collection, we explored documentary observation and bibliographic research in the Science Direct and Web of Science databases. The study focuses on research areas related to maintenance integration, Industry 4.0 (Techno centric) and human-centric characteristics (Industry 5.0). The article brought important conclusions, as it addresses the impact and trends on the factory floor so that managers can develop competitiveness and productivity. The article highlights the role of maintenance methods in improving factory floor performance, emphasizing human knowledge and Prescriptive Maintenance practices to ensure operations within World Class standards.

Evaluation of Pedestrian-Induced In-Service Building Floor Performance Based on Short-Term Monitoring

Evaluation of Pedestrian-Induced In-Service Building Floor Performance Based on Short-Term Monitoring

Effective bi-directional overlapped sliding window decoding of SC-LDPC codes

In this paper, a bi-directional sliding window decoder is proposed for spatially coupled low-density parity-check (SC-LDPC) codes, which improves the decoding complexity and performance compared to the conventional sliding window decoding (SWD) by sharing messages at the overlapped part of forward and backward decoding windows. Moreover, by using proper scaling factors that determine the weight of each message at the overlapped part of two sliding windows, good local decoding effects can be efficiently spread out to both ends of SC-LDPC code during decoding process. Such effective message updates of the proposed bi-directional overlapped sliding window decoding (BO-SWD) improve error floor performance compared to the conventional SWD. The validity of BO-SWD is verified by simulation with various SC-LDPC ensembles.

Radiant Floor Cooling Systems: A Critical Review of Modeling Methods

Radiant floor heating systems have become a reference technology, but their use for cooling purposes has proven inconvenient in many applications due to their reduced cooling capacity and condensation issues. Nonetheless, potentialities and drawbacks of radiant floor cooling systems have been frequently addressed and simulated, given the large potential advantages of employing a single emissive system for all seasons. This paper aims to provide a comprehensive review of the modeling methods for radiant floor cooling systems proposed in scientific papers and also used in simulation software and technical standards. Models are classified according to their characterizing features, and the distinctive contributions of each method are discussed. Additionally, the modeling of the most relevant phenomena affecting floor performance is further discussed. The review revealed the presence of two main modeling classes, one only focusing on the floor’s conductive heat transfer and the other integrating active floor analysis within the building’s energy model of the thermal zone. Despite the presence of many modeling methods that are able to consider the most important effects in the radiant cooling system operation, not all the phenomena present in a practical application are fully described. Therefore, there is an ongoing need for more comprehensive, possibly easily characterizable, modeling approaches.

Shop floor performance feedback, employee's motivation and engagement: study of a beverage distribution company

PurposeThis paper aims at examining how different types of shop floor performance feedback affect employee motivation and engagement. Based on this dataset, the authors analyzed the relationship between five types of performance feedback (safety, quality, productivity, improvement and individual performance) and three types of human-related outputs (motivation, role clarity and engagement) in light of socio-technical systems theory.Design/methodology/approachThe authors designed a survey instrument and collected data from 492 employees of a large beverage distribution company. The authors used robust construct validity tests and multiple regression analysis to test the hypotheses.FindingsThe findings indicated significant positive effects of feedback on overall production, improvements and individual performance on all human-related outputs. In turn, safety and quality performance feedback had no statistically significant impact in motivation or engagement. These findings highlight the mixed nature of the impact of performance feedback on human-related outputs that have been neglected in the literature.Originality/valueThe joint analysis of the social and technical portion of performance feedback is unusual despite its clear relevance, which characterizes an original contribution of the authors’ work. Although previous literature supports the effect of performance feedback on motivation and engagement, previous studies have not tested how different types of feedback affect those social constructs.

Improved heating floor thermal performance by adding PCM microcapsules enhanced by single and hybrid nanoparticles

AbstractA heating floor is a low‐temperature emitter consisting of pipelines in which a fluid circulates between 35°C and 45°C. To ensure energy efficiency, occupant comfort, and building material durability, proper heat management is crucial in buildings. By using phase change materials (PCMs) in building envelopes, the indoor temperature can be regulated through the storage and release of thermal energy, which reduces energy consumption and enhances occupant comfort. In this study, we evaluated numerically a heating floor that incorporates a PCM enhanced by nanoparticles (NePCM). The aim of the numerical analysis is to assess the impact of the addition of single and hybrid nanoparticles in different proportions to the PCM layer on the thermal performance of the PCM‐based floor. Therefore, two main objectives are defined. The primary is to take advantage of the storage capacity of a PCM layer by integrating it into the ground; second, to evaluate the hot water temperature levels effect on the floor's performance. Additionally, we address the low thermal conductivity of PCM by enhancing PCM microcapsules with single and hybrid nanoparticles and comparing them to pure PCM. The numerical results obtained show that positioning the PCM microcapsules above the heating tubes (upper position) provides an optimum improvement in thermal performance. Moreover, the addition of hybrid nanoparticles within the base PCM, 1% of Cu mixed with 4% of Al2O3, allows an increase of 4°C, which relates to a reduction of 18% in the internal temperature amplitude and a phase shift of 6 h 30 min compared with the conventional heated floor in which there is no PCM.

Investigating the use of dynamic sub-structuring methods in predicting floating floor performance.

Floating floors are a common means of reducing airborne and structure-borne noise, however, prediction of in-situ performance remains a challenge for many consultants. The specification of such floors, usually based on single degree of freedom assumptions, does not account for the influence of floating floor dynamics, dynamics of host structures or interplay/power flow between the two via the isolating mounts. Reliance on single degree of freedom systems tend to over-predict the performance of the floating floor element, often leading to noise/vibration issues in the finished construction. A more robust approach is needed, though is challenging due to complexities in characterising large-scale constructions, where source-to-receiver Frequency Response Functions (FRFs) must account for multiple points of contact between floating and structural elements. This paper first presents a hybrid method for evaluating the source-receiver FRF of a simple floating floor via a sub-structured approach, and confirms the validity of the method to that of the source-receiver FRF measured directly. Efforts to simplify the analysis to a set of engineering-grade operations is also presented, the aim being movement towards a methodology that can be more readily utilised by practitioners, without the need for expensive modelling software or high end hardware setups.

Análise experimental de vibrações induzidas pelo caminhar em sistemas compostos de pisos e avaliação do desempenho considerando o conforto humano

Abstract NBR 8800 was updated in the year of 2008. Acceptance criteria of vibrations on floor performance considering human comfort were simplified and only minimum values of fundamental frequency are considered for performance evaluation. The objective of this article is to evaluate a methodology of experimental analysis of footfall-induced vibrations in steel and composite system floors and footbridges in order to check the human comfort conditions. The methodology was established according to international standard recommendations and international design guides. In order to present its applicability, it was applied to four case studies. The spectrum processing provided the values of natural frequency, damping ratio and peak acceleration. All the floors presented values of fundamental frequency greater than the minimum values recommended by NBR 8800. However, the obtained peak acceleration for some cases presented values greater than the maximum value recommended by international criteria. Therefore, the simplified acceptance criteria proposed by NBR 8800 were insufficient for performance assessment of some system floors and footbridges.

Operator-Based Adaptive Tracking Capacity Control in Complex Manufacturing Processes

Nowadays, quickly changing customer demands are a big challenge in the manufacturing industry, especially for job shops, which are typical coupling and nonlinear multi-input–multi-output (MIMO) systems. In order to achieve good shop floor performance in the presence of short-term demand fluctuations, a key performance indicator—work in process (WIP)—is required to be effectively controlled in the vicinity of the desired levels. For this purpose, a machinery-oriented capacity adjustment approach via a reconfigurable machine tool (RMT) is employed to flexibly balance capacity and load in the case of a bottleneck. A mathematical model concerning the RMT and WIP was first established in the presence of uncertainty and delays. The operator-based robust right coprime factorization (RRCF) method was adopted to stabilize the uncertain system, and adaptive integral separated proportional–integral (ISPI) tracking controllers were further designed to improve the transient and robustness performance. The performance of the proposed ISPI-RRCF was analyzed and compared with that of a state-of-the-art method in a simulation. The results showed that both control systems could ensure that the WIP was within an allowed bound, while the former had lower overshoots, shorter setting times, and more concentrated distributions facing stochastic demands. This further indicated the effectiveness of the proposed algorithm in the avoidance of serious bottlenecks and unbalanced capacity distributions.

Multi-Layer Progressive Tree-Structured Edge Growth Algorithm for Nested Lifting Design of 5G-NR-Like LDPC Codes

We proposed an algorithm called multi-layer progressive tree-structured edge growth, to design rate-compatible length-scalable raptor-like quasi-cyclic LDPC codes with nested base matrices and nested lifting, like 5G new radio (NR) LDPC codes. The nested lifting design is mainly investigated in this letter. To deal with the complicated dependency of the performance for nested base matrices and lifting sizes simply and effectively, the design of nested lifting is decomposed into the lifting design of each lifting size, which is called a layer. In each layer, the lifting of nested base matrices is designed via progressive tree-structured edge growth algorithm, where tree structure is employed to reserve diversified intermediate results and achieve better trade-off of error floor performance among nested base matrices. The criterion composed of improved cycle classification, minimum distance test and performance evaluation is employed for tree pruning, which could better optimize the error floor performance under acceptable complexity. The effectiveness of the proposed algorithm is demonstrated via construction and simulation.

Fully Absorbing Set Enumerators for Protograph-Based LDPC Code Ensembles

The average finite-length (elementary) fully absorbing set enumerators for binary protograph-based low-density parity-check (LDPC) code ensembles are derived. The method relies on generating functions, and it provides an efficient mean to obtain the normalized logarithmic asymptotic distribution of (elementary) fully absorbing sets. Using these results, the asymptotic distribution of (elementary) fully absorbing sets is evaluated for some protograph-based LDPC code ensembles. Numerical results show how the distributions can be used to estimate the error floor performance of protograph LDPC codes.

The relationship between handgrip strength and performance scores in North American Collegiate Division I women’s artistic gymnasts

Maximal isometric handgrip strength (HGS) is used as an indicator of overall muscular strength and has also been found to be predictive of certain athletic events sporting prowess. Women’s artistic gymnastics requires athletes have high levels of relative muscular strength and power to be successful. This study examined the relationship between HGS and gymnastics performance scores for the 4 events of vault, uneven bars, beam, and floor in female collegiate artistic gymnasts. Twenty-five (n=25) female National Collegiate Athletic Association (NCAA) Division I North American collegiate women’s artistic gymnasts (age: 20.1±1.3 yrs; height: 158.9±5.6 cm; mass: 58.2±5.3 kg) were assessed for a one-time measurement of absolute HGS in kg and relative HGS (HGS/height in m2), as well as their average vault, uneven bars, beam, and floor performance scores across a competitive season. Pearson correlation coefficients (r) were determined between HGS and all performance scores. No significant (p > 0.05) correlations were found between absolute HGS (30.8±4.4 kg) or relative HGS (12.0±1.6 kg/m2) and any 4 gymnastics event’s performance scores (r range: -0.07 – 0.50 or r range: -0.06 – 0.31, respectively). In this female collegiate gymnastics’ population, 56% had an absolute HGS and 80% had a relative HGS, respectively, above the 50th percentile of all similarly aged adult females in the United States. In the current population of female collegiate gymnasts, absolute and relative HGS were not related to any gymnastics events performance scores and adds to the existing literature, supporting no relationships between HGS and sports performances where sports movements require a high degree of technical precision and accuracy. Findings from this investigation can be used by athletes, coaches, and practitioners in the collegiate women’s gymnastics realm to assess if athletes have attained sufficient absolute HGS, and especially relative HGS values, to be successful.

Sub-Block Rearranged Staircase Codes

We propose a new family of spatially coupled product codes, called sub-block rearranged staircase (SR-staircase) codes. Each code block of SR-staircase codes is obtained by encoding rearranged preceding code blocks and new information blocks, where the rearrangement involves sub-blocks decomposition and transposition. The proposed codes can be constructed to have each code block size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1/q$ </tex-math></inline-formula> to that of the conventional staircase codes while having the same rate and component codes, for any positive integer <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$q$ </tex-math></inline-formula> . In this regard, we can use strong algebraic component codes to construct SR-staircase codes with a similar or the same code block size and rate as staircase codes with weak component codes. We characterize the decoding threshold of the proposed codes under iterative bounded distance decoding (iBDD) by using density evolution. We also derive the conditions under which they achieve a better decoding threshold than that of staircase codes. Further, we investigate the error floor performance by analyzing the contributing error patterns and their multiplicities. Both theoretical and simulation results show that the designed SR-staircase codes outperform staircase codes in terms of waterfall and error floor while the performance can be further improved by using a large coupling width.

Experimental Investigation on the Structural Performance of Mass Timber Panel-Concrete Composite Floors with Notched Connections

Mass timber panel (MTP)-concrete composite floors are gaining increasing interest from builders and designers due to their optimized structural performance, light self-weight, and aesthetically exposed wood ceilings. Among various connecting techniques between timber and concrete, notched connections made by cutting grooves on timber and filling them with concrete are considered as one of the most structurally efficient and cost-saving connecting solutions. Numerous ways of making and reinforcing the notched connections, however, hinder the standardization and development of the design guidelines for this type of connection, which reduces the competitiveness of MTP-concrete composite floors. In this study, experiments were carried out to investigate the performance of MTP-concrete composite floors with different connection designs. Nine composite floor specimens with varying span, connection number, notch depth, concrete thickness, and loading direction were designed and tested under bending. The bending stiffness, load-carrying capacity, ductility, and failure mode of tested specimens were studied and discussed. Test results show that the connection number, notch depth, and concrete thickness affect the bending stiffness and strength of the floor positively, an increase in floor span impacts the floor performance negatively, whereas the effect of a limited number of self-tapping screws in the notch is negligible. The study also shows that MTP-concrete composite floors with high strength, high stiffness, and good ductility can be achieved through the optimized design of notched connections.

Effects of Body Composition on Weight-Bearing Staging in Firefighters

Firefighters are often exposed to traumatic events such as high temperatures, heavy fumes, and toxic gases during rescue services. The challenges require firefighters to have a higher level of physical performance compared to a typical person. In urbanized settings, weight-bearing staging is a necessary skill for firefighters. Currently, research has found a positive correlation between firefighter body composition and occupational activity performance. This study aims to examine effects of body composition on the weight-bearing staging performance of firefighters, providing guidance for firefighters' daily training routines. Participants were 47 male firefighters in Yangjiang City, Guangdong Province (age: 25.2 ± 3.9; height: 169.8 ± 5.1cm; 68.9 ± 8.0kg; 24.2 ± 2.4kg / m2). Load climbing tests were organized by the fire rescue brigade in Yangjiang City. The tested wore a full set of fire protective clothing, carried a positive pressure air respirator and carried two water belts (with a total load of 30kg), climb to a 10-story building and record the test completion time by manual timing. For body compositions, body weight, body fat, skeletal muscle content and lean weight were measured by machine with the help of Inbody 360 body composition tester. Linear and PLS regressions were used for data analysis. In the Gray's association degree analysis, the association degree of the weight indicators was ranked first, meaning that weight had the strongest association with weight-bearing indoor performance. In linear regression analysis, the model equation was derived as follows: weight-bearing floor performance (s) = 16.20 + 0.9056 * weight (kg), and the R-square of the model was 0.1927, implying that body weight could explain 19.27% of the variance in weight-bearing floor performance. An F-test of the linear model yielded F = 10.74, P &lt; 0.05. In the PLS regression analysis, the principal component of 1 was the optimal number of extractions from the projection importance index VIP value, and the final result was that the regression of weight and body fat on weight-bearing dengue performance had a significant effect. Based on the results, the highest association emerged between weight and weight-bearing performance; weight had a significant effect on the weight-bearing performance, with greater weight-bearing sitting time; weight and body fat had significant effects on weight-bearing staging performance. To maintain adequate occupational mobility, firefighters are recommended to manage body composition through aerobic endurance and strength training.

Design Improvements on Fast, High-Order, Incremental Sigma-Delta ADCs for Low-Noise Stacked CMOS Image Sensors

Modern CMOS imaging devices are present everywhere, in the form of line, area and depth scanners. These image devices can be used in the automotive field, in industrial applications, in the consumer’s market, and in various medical and scientific areas. Particularly in industrial and scientific applications, the low-light noise performance or the high dynamic-range features are often the cases of interest, combined with low power dissipation and high frame rates. In this sense, the noise floor performance and the power consumption are the focus of this work, given that both are interlinked and play a direct role in the remaining sensor features. It is known that thermal and flicker noise sources are the main contributors to the degradation of the sensor performance, concerning the sensor output image noise. This paper presents an indirect way to reduce both the thermal and the flicker noise contributions by using thin-oxide low voltage supply column readout circuits and fast 3rd order incremental sigma-delta converters with noise shaping capabilities (to provide low noise output digital samples—74 μVrms; 0.7 e−rms; at 105 μV/e−), and thus performing correlated double sampling in a short time (19 μs), while dissipating significant low power (346 μW). Throughout the extensive parametric transistor-level simulations, the readout path produced 1.2% non-linearity, with a competitive saturation capacity (6.5 ke−) pixel. In addition, this paper addresses the readout parallelism as the main point of interest, decoupling resolution from the image noise and the frame rate, at virtually any array resolution. The design and simulations were performed with Virtuoso 6.17 tools (Cadence Design Systems, San Jose, CA, USA) using Spectre models from TS18IS Image Sensor 0.18 µm Process Development Kit (Tower Jazz Semiconductor, Migdal Haemek, Israel).

Thickness-resonance waves in underlays of floating screed

The prediction of the reduction of impact sound pressure level ΔL according to annex C of the standard ISO 12354-2 gives an acceptable estimation of the floating floor's performance for thin resilient layers. However, the performance is often largely overestimated for thick resilient layers or for resilient layers combined with thermal layers. One reason for this is that the simplified model doesn't account for the thickness resonances in the underlays which can greatly affect ΔL. This is confirmed by comparing finite element and transfer matrix method simulations with experimental results. This paper establishes the mechanisms leading to the development of these resonance waves and provides some guidelines to estimate their negative effects on the ΔL.

Spatially Coupled Generalized LDPC Codes: Asymptotic Analysis and Finite Length Scaling

Generalized low-density parity-check (GLDPC) codes are a class of LDPC codes in which the standard single parity check (SPC) constraints are replaced by constraints defined by a linear block code. These stronger constraints typically result in improved error floor performance, due to better minimum distance and trapping set properties, at a cost of some increased decoding complexity. In this paper, we study spatially coupled generalized low-density parity-check (SC-GLDPC) codes and present a comprehensive analysis of these codes, including: (1) an iterative decoding threshold analysis of SC-GLDPC code ensembles demonstrating capacity approaching thresholds via the threshold saturation effect; (2) an asymptotic analysis of the minimum distance and free distance properties of SC-GLDPC code ensembles, demonstrating that the ensembles are asymptotically good; and (3) an analysis of the finite-length scaling behavior of both GLDPC block codes and SC-GLDPC codes based on a peeling decoder (PD) operating on a binary erasure channel (BEC). Results are compared to GLDPC block codes, and the advantages and disadvantages of SC-GLDPC codes are discussed.

The Effects of a 10-Week Neuromuscular Training on Postural Control in Elite Youth Competitive Ballroom Dancers: A Randomized Controlled Trial.

The purpose of this randomized controlled trial was to evaluate the efficacy of a 10-week neuromuscular training (NMT) program on the postural control of elite youth competitive ballroom dancers. Forty-two dancers (21 couples) were randomly assigned to either the NMT group (n = 22) or the control group (CG; n = 20). Participants in NMT underwent a three-sessions-per-week NMT program for 10 weeks. Testing at baseline and after the 10 weeks intervention included the Y-balance test (YBT) and Modified-Balance Error Scoring System (M-BESS). Results of YBT indicated that NMT participants demonstrated increased reach in the posterolateral and posteromedial directions for the right and left lower limb, whereas no significant change was found in the anterior direction for both limbs. Results of Modified-Balance Error Scoring System (M-BESS) showed that NMT participants displayed significantly decreased errors of the double-leg floor (p = 0.026), single-leg foam (p = 0.010), double-leg foam (p = 0.003), tandem floor (p = 0.031), and tandem foam (p = 0.038), while no significant change was found in single-leg floor performance (p = 0.476). CG participants did not exhibit any significant change during the 10-week period. In summary, the study affirmed that the 10-week NMT program enhanced the postural control performance of youth ballroom dancers and showed effects on ballroom dance-specific performance and lower-limb injury prevention. The results suggest that NMT may be a valuable addition to ballroom dance training regimens.

Construction of Time Invariant Spatially Coupled LDPC Codes Free of Small Trapping Sets

In this paper, we propose a design technique for the construction of variable-regular time-invariant spatially-coupled low-density parity-check (SC-LDPC) codes with small constraint length and low error floor. The proposed technique reduces the error floor by imposing simple constraints on the short cycles in the code's Tanner graph, which in turn, result in the elimination of the most dominant trapping sets of the code. In some cases, we also derive lower bounds on the syndrome former memory for satisfying such constraints. The designed codes are superior to the state-of-the-art in terms of error floor performance and/or decoding complexity and latency.