Performance-based Method Research Articles

Seismic Design and Evaluation Methods for Small-to-Medium Span Highway Girder Bridges Based on Machine Learning and Earthquake Damage Experience

This study summarized the application field of machine learning to explore the basic seismic thinking of machine learning methods used for bridges. The development and actuality of bridge seismic analysis theories and technology were briefly reviewed, particularly in relation to the field of civil engineering. This study introduced the concept of machine learning, summarized its key factors and current software platforms, and illustrated the common methods and representative algorithms of machine learning using simple examples. First, the normal types of simply supported and continuous girder bridges, which are used for highway bridges with small and medium spans in China, were summarized. The earthquake damage phenomena had been observed for bridge types during the Wenchuan earthquake. Data from these phenomena were assessed, including the damage grade divisions of piers, bearings, shear keys, and abutments. Second, a series of seismic performance tests had been conducted by international and domestic academics for bearings, shear keys, piers, and abutments. These tests were summarized in this study to obtain the constitutive relationships for seismic analysis and determine the seismic design parameters of bridge components (including foundations). Finally, an overall analysis methodology based on machine learning was introduced into the bridge seismic analysis. This methodology explained that machine learning for bridge seismic tasks had two aspects. The first was the collection of considerable bridge design data and set up data sets, and the second was data reduction, including raw data processing and debugging or developing a reasonable machine learning algorithm model. This study also discussed the shortcomings of existing performance-based probabilistic seismic design and evaluation methods that are currently used in analyzing bridges in China. Results indicated the potential future major concerns for bridge seismic analysis technology. The establishment of computational simulations based on artificial intelligence method was also recommended. In addition, the mutual integration between disciplines and mutual communication among different professionals were advocated in this study.

A Multimodal Interface for Virtual Character Animation Based on Live Performance and Natural Language Processing

ABSTRACTVirtual character animation is receiving an ever-growing attention by researchers, who proposed already many tools with the aim to improve the effectiveness of the production process. In particular, significant efforts are devoted to create animation systems suited also to non-skilled users, in order to let them benefit from a powerful communication instrument that can improve information sharing in many contexts like product design, education, marketing, etc. Apart from methods based on the traditional Windows-Icons-Menus-Pointer (WIMP) paradigms, solutions devised so far leverage approaches based on motion capture/retargeting (the so-called performance-based approaches), on non-conventional interfaces (voice inputs, sketches, tangible props, etc.), or on natural language processing (NLP) over text descriptions (e.g., to automatically trigger actions from a library). Each approach has its drawbacks, though. Performance-based methods are difficult to use for creating non-ordinary movements (flips, handstands, etc.); natural interfaces are often used for rough posing, but results need to be later refined; automatic techniques still produce poorly realistic animations. To deal with the above limitations, we propose a multimodal animation system that combines performance- and NLP-based methods. The system recognizes natural commands (gestures, voice inputs) issued by the performer, extracts scene data from a text description and creates live animations in which pre-recorded character actions can be blended with performer’s motion to increase naturalness.

Performance-Based Evaluation of a Double-Deck Tunnel and Design Optimization

The double-deck tunnel is well known as smart infrastructure because multiple sections can be used for various purposes. Although the stability of a double-deck tunnel is mainly governed by the intermediate slab, the effect of various governing factors on tunnel structural stability has not been fully investigated. In this study, performance-based evaluation method for a double-deck tunnel is suggested as a three-dimensional matrix considering the life cycle of a double-deck tunnel. Moreover, a customized software for design and maintenance of a double-deck tunnel is developed. A structural analysis solver based on a beam–spring model for a double-deck tunnel was embedded in this code. The effects of connection type as well as depth of tunnel, ground stiffness and traffic load on structural behavior of tunnel were investigated. From the analysis, it was found that the connection type between segment lining and intermediate slab significantly affects the behavior of segment lining: simply connected condition causes lesser stress and moment than fully fixed condition. The deeper the tunnel depth, the greater the member force of segment lining. In addition, as both the tunnel depth and the ground stiffness increase, the influence of connection type on the structural stability of the double-deck tunnel becomes insignificant.

Conceptualizing and Assessing Everyday Functioning in the Context of HIV-Associated Neurocognitive Disorders.

Combination antiretroviral therapy has reduced the rates of severe HIV-associated neurocognitive disorders (HAND), but the prevalence of milder forms of HAND that can affect everyday functioning remains high. As HIV-infected adults approach near-normal life expectancies, they may become increasingly susceptible to declines in everyday functioning secondary to a variety of physical and mental factors, including HAND. Although impairments in everyday functioning are a hallmark of HAND diagnoses and can adversely influence quality of life, there are no gold standard measures of this fundamentally important and complex construct. This chapter provides a brief review of the various self-report, clinician-rated, and performance-based methods by which everyday functioning is measured in the setting of HIV disease, including global activities of daily living and specific domains of medication adherence, financial management, automobile driving, and vocational functioning.

The length of plastic hinge area in the flanged reinforced concrete shear walls subjected to earthquake ground motions

Past earthquakes have shown that appropriately designed and detailed buildings with shear walls have great performance such a way that a considerable portion of inelastic energy dissipation occurs in these structural elements. A plastic hinge is fundamentally an energy diminishing means which decrease seismic input energy through the inelastic deformation. Plastic hinge development in a RC shear wall in the areas which have plastic behavior depends on the ground motions characteristics as well as shear wall details. One of the most generally used forms of structural walls is flanged RC wall. Because of the flanges, these types of shear walls have large in-plane and out-of-plane stiffness and develop high shear stresses. Hence, the purpose of this paper is to evaluate the main characteristics of these structural components and provide a more comprehensive expression of plastic hinge length in the application of performance-based seismic design method and promote the development of seismic design codes for shear walls. In this regard, the effects of axial load level, wall height, wall web and flange length, as well as various features of earthquakes, are examined numerically by finite element methods and the outcomes are compared with consistent experimental data. Based on the results, a new expression is developed which can be utilized to determine the length of plastic hinge area in the flanged RC shear walls.

Optimization of deep mixing design for seismic liquefaction mitigation of Caisson walls

Gravity caisson wall is a common waterfront construction that were severely damaged by soil liquefaction in previous earthquakes. The deep mixing method is regarded as effective in liquefaction remediation. Meanwhile, an easily-executable remedial design procedure of using the deep mixing method for caisson walls exposed to seismic liquefaction risk has not been well developed for routine constructions. To solve the issue by following the philosophy of the Performance-Based Design method, the deep mixing method is examined within a framework of a well-calibrated case history to provide hypothetical mitigation to a damaged caisson wall to reach the acceptable level under the identical cyclic loadings as recorded in the case history. The study is divided into two steps: (1) a case history of damaged caisson wall by seismic-induced soil liquefaction was verified; (2) the deep mixing method is hypothetically applied to the caisson wall before the occurrence of earthquake, and the remedial design is optimized based on the improved wall structure deformation under seismic loading. The remedial design including the locations and configurations of deep mixing elements are optimized. Insights and recommendations on the establishment of liquefaction mitigation design and optimization process for caisson quay walls are provided to the practice.

Modeling methane oxidation in landfill cover soils as indicator of functional stability with respect to gas management

ABSTRACTA performance-based method for evaluating methane (CH4) oxidation as the best available control technology (BACT) for passive management of landfill gas (LFG) was applied at a municipal solid waste (MSW) landfill in central Washington, USA, to predict when conditions for functional stability with respect to LFG management would be expected. The permitted final cover design at the subject landfill is an all-soil evapotranspirative (ET) cover system. Using a model, a correlation between CH4 loading flux and oxidation was developed for the specific ET cover design. Under Washington’s regulations, a MSW landfill is functionally stable when it does not present a threat to human health or the environment (HHE) at the relevant point of exposure (POE), which was conservatively established as the cover surface. Approaches for modeling LFG migration and CH4 oxidation are discussed, along with comparisons between CH4 oxidation and biodegradation of non-CH4 organic compounds (NMOCs). The modeled oxidation capacity of the ET cover design is 15 g/m2/day under average climatic conditions at the site, with 100% oxidation expected on an annual average basis for fluxes up to 8 g/m2/day. This translates to a sitewide CH4 generation rate of about 260 m3/hr, which represents the functional stability target for allowing transition to cover oxidation as the BACT (subject to completion of a confirmation monitoring program). It is recognized that less than 100% oxidation might occur periodically if climate and/or cover conditions do not precisely match the model, but that residual emissions during such events would be de minimis in comparison with published limit values. Accordingly, it is also noted that nonzero net emissions may not represent a threat to HHE at a POE (i.e., a target flux between 8 and 15 g/m2/day might be appropriate for functional stability) depending on the site reuse plan and distance to potential receptors.Implications: This study provides a scientifically defensible method for estimating when methane oxidation in landfill cover soils may represent the best available control technology for residual landfill gas (LFG) emissions. This should help operators and regulators agree on the process of safely eliminating active LFG controls in favor of passive control measures once LFG generation exhibits asymptotic trend behavior below the oxidation capacity of the soil. It also helps illustrate the potential benefits of evolving landfill designs to include all-soil vegetated evapotranspirative (ET) covers that meet sustainability objectives as well as regulatory performance objectives for infiltration control.

Robustness of Performance-Based Plastic Design Method for SMABFs

Shape memory alloys (SMAs) are gaining increasing attentions from earthquake engineering community, due to the superleastic property, which is capable of offering energy dissipation capacity and recentering ability to various structural systems. SMA braced frames (SMABFs) are emerging as promising frames with advanced seismic resilience. Recently, the performance-based plastic design (PBPD) method was developed for such structural system. However, the robustness of this design approach still needs rigorous examinations by addressing the effects of defining different performance targets or using different seismic design spectra in the design procedure. In doing so, examinations were carried out from two perspectives. The first one set various performance targets combining different interstory drift ratio and brace ductility demand in the design procedure based on the design basis earthquake spectrum, and then the resulting SMABFs were subjected to earthquake ground motions corresponding to design basis hazard level. The second one conducted the design procedure at three seismic hazard levels representative of frequently occurred earthquake, design basis earthquake, and maximum considered earthquake, respectively, and then assessed the seismic performance upon earthquakes associated with three seismic intensities. The analytical results show that the designed frames as per the PBPD method always coincide with the performance targets very well, regardless of the prescribed targets and adopted design spectrum. Therefore, this paper provided sound results which successfully demonstrated the high robustness of the previously developed PBPD method for SMABFs.

Is Performance Measurement Improving Planning Practice? The Case of Location Affordability in Long-Range Transportation Plans

Transportation planning in the United States is moving to widespread use of performance-based planning methods as new federal requirements for metropolitan planning organizations (MPOs) are implemented. In addition to requirements for measures of safety, infrastructure condition, and travel reliability, many MPOs are adopting additional performance measures including those of complex socioeconomic issues. This study explores current planning practice in using a performance-based approach to tackle such an issue: location affordability, defined as an affordable level of combined cost burdens for housing and transportation. A review of long-range transportation plans at 21 large MPOs provides information on how location affordability is represented in regional transportation plans, how it is defined and measured, and how it is integrated into the planning process. The results are interpreted using a theoretical framework designed to help match planning methods to the conditions of a planning situation. The framework, Christensen’s matrix of planning problems, provides insights into the use of performance measures for location affordability and how performance measurement programs can be designed to support more effective planning for this and similarly challenging issues.

Sustainability of integrated energy systems: A performance-based resilience assessment methodology

One of the key elements of any community or facility is the integrated energy system (IES) which consists of utility power plants, distributed generation systems, and building heating and cooling systems. Assessing the sustainability of an IES would be of great value to decision-making relevant to design, future growth planning, and operation of such systems. This paper addresses one of the basic issues in this regard, i.e. resilience assessment and quantification of IES. A new performance-based method for characterizing and assessing resilience of multi-functional demand-side engineered systems is proposed in this study. Through modeling of system response to potential internal and external failures (called failure modes) during different operational temporal periods (such as different diurnal and seasonal periods of the year), the proposed methodology quantifies resilience of the system based upon loss in the services which the system is designed to deliver. A three-dimensional matrix, called Loss Matrix, is introduced whose elements represent the undelivered system services under different scenarios, i.e. combinations of failure modes and different operational temporal periods. Assigning monetary penalty costs to such losses and including them in the objective function of an optimization model of the entire system allows the three-dimension loss matrix to be reframed into a two-dimensional Consequence Matrix where individual elements represent the imposed penalty costs to the system stakeholders due to undelivered services and/or non-optimal system performance. Normalizing the individual elements results in the Resilience Matrix of the system for different scenarios. The developed methodology is illustrated for IES of a large office building serves to satisfy critical and noncritical electrical, heating, and cooling loads. The resilience assessment framework proposed in this paper would serve as a mean to identify critical components of a particular IES, thereby facilitating resilient design and operation, and also to evaluate cost-effective resilience enhancement strategies.

Fire Safety Parameters of High-Rise Residential Building: A Literature Review of Performance-Based Analysis Method

The basic concept in occupant safety assessments in high-rise building residential against fire hazard is the determination of the time the occupants can be safe/escape before the fire danger conditions occur. This concept is also called performance-based appraisal. It is known by another name Available Safety Egress Time > Required Safety Egress Time (ASET> RSET). The concept of performance-based fire safety assessment has been widely used in the concept of fire safety. Discussions related to this literature study are focused on strength and weaknesses in ASET and RSET methodologies, which are related to the parameters. This paper provides a brief overview of the methodologies and parameters of ASET and RSET. The results of this literature study provide a clear picture that the simulation of fire hazards in high-rise residential buildings can be done accurately by considering the parameters of the ASET and RSET. However the lack of resources and experts in using this related software make this performance-based method is difficult to achieve.

Thermal performance evaluation of low-income buildings based on indoor temperature performance

In South Korea, about 40,000 buildings of low-income households have been diagnosed and remodeled annually by the Energy Welfare Program, using the normative method. The normative method is based on the heat gain elements of a building. In contrast, the performance-based method is based on the output derived from the thermal performance of each building part. In the normative method, there is no other building in which the input conditions of a building are perfectly matched. Further, cost-effective energy remodeling strategies vary according to the capacity of the diagnosis engineer. In this paper, we analyze the thermal performance of buildings by the performance-based method using indoor temperature, and examine the possibility of a database for the optimal remodeling method. For this, we analyzed more than 2500 simulation cases by combining thermal performance of each building part. The indoor temperature pattern can be similar even when the thermal performance of each building part is different. In buildings with similar indoor temperature patterns, the coefficient of variation of the root mean squared error of energy demand falls within the acceptable error range. Furthermore, changes in energy demand and predicted mean vote are similar when window thermal performance is changed.

Recognition of Physical Activities from a Single Arm-Worn Accelerometer: A Multiway Approach

In current clinical practice, functional limitations due to chronic musculoskeletal diseases are still being assessed subjectively, e.g., using questionnaires and function scores. Performance-based methods, on the other hand, offer objective insights. Hence, they recently attracted more interest as an additional source of information. This work offers a step towards the shift to performance-based methods by recognizing standardized activities from continuous readings using a single accelerometer mounted on a patient’s arm. The proposed procedure consists of two steps. Firstly, activities are segmented, including rejection of non-informative segments. Secondly, the segments are associated to predefined activities using a multiway pattern matching approach based on higher order discriminant analysis (HODA). The two steps are combined into a multi-layered framework. Experiments on data recorded from 39 patients with spondyloarthritis show results with a classification accuracy of 94.34% when perfect segmentation is assumed. Automatic segmentation has 89.32% overlap with this ideal scenario. However, combining both drops performance to 62.34% due to several badly-recognized subjects. Still, these results are shown to significantly outperform a more traditional pattern matching approach. Overall, the work indicates promising viability of the technique to automate recognition and, through future work, assessment, of functional capacity.

A performance-based subsidy allocation of ferry transportation: A data envelopment approach

Ferry transportation plays an essential role in transportation services between a mainland and its offshore islands, as well as among those islands. However, low volume routes frequently operate at a loss because they are socially necessary but not profitable. Thus, a government may provide financial support to such ferry routes. Since budgetary resources for offshore ferry routes are limited, this paper offers a performance-based method constructed through data envelopment analysis to help governments allocate subsidies to individual offshore ferry routes. The proposed method considers the concepts of cross-efficiency and structural efficiency, simultaneously. The allocation results for a current ferry subsidy allocation policy and the proposed method are compared. The results may provide valuable suggestions for allocation policies for subsidies to ferry firm.

Influencia del mallado en el modelado computacional de incendios en centrales nucleares

Los modelos computacionales de incendio permiten estudiar las consecuencias de los incendios en escenarios reales. Su uso para el análisis y la mejora de la seguridad contra incendios en centrales nucleares se ha visto incrementado al publicarse la normativa que permite el empleo de métodos informados por el riesgo y basados en prestaciones. La selección del tamaño de celda es fundamental en estos modelos. El mallado debe establecer un compromiso entre su ajuste a la geometría, la resolución de las ecuaciones y los tiempos de cómputo. El presente artículo estudia distintos tamaños de celda mediante la herramienta FDS, con el objetivo de evaluar su influencia en los resultados simulados. Como punto de referencia se emplearon escenarios de interés en centrales nucleares. Los resultados ofrecen datos relevantes para los usuarios, mostrando los tamaños de celda óptimos para garantizar la calidad de las simulaciones y reducir las incertidumbres en sus resultados.

A performance-based method for the design of drainage trenches used to stabilize slopes

Drainage trenches are widely used as a measure for slope stabilization. Their effect is generally quantified in terms of a safety factor against a possible collapse mechanism of the slope. A more rational and economical design approach consists in admitting the occurrence in some time intervals of limit conditions in the slope, and evaluating the performance of the slope in terms of accumulated permanent displacements of the unstable soil mass. The resulting displacements should avoid the occurrence of significant damage and preserve the serviceability of existing structures. In this context, a new method is proposed in the present paper for the design of drainage trenches used to control the mobility of translational landslides periodically activated by rainfall. This method is based on some analytical equations that relate rain to the groundwater regime as modified by the trenches, and a simple sliding block model to evaluate the landslide displacements. The proposed method also accounts for the delay of the hydraulic response at different depths. The above-mentioned equations are validated by several comparisons with numerical results obtained using a finite element code or published in the literature. Finally, the method is applied to some case studies to show the effectiveness of the drainage trenches to control the landslide mobility owing to rainfall.

Convergent and concurrent validity of a report- versus performance-based evaluation of everyday functioning in the diagnosis of cognitive disorders in a geriatric population.

This was a cross-sectional study, undertaken in a geriatric day hospital. The participants comprised community-dwelling HCs (n = 21, median age 78.0 years, 61.9% female), MCI (n = 20, median age 79.5 years, 55.0% female), and AD (n = 20, median age 80.0 years, 85.0% female) adults. A diagnostic procedure for neurocognitive disorders was employed. In addition, the a- and i-ADL tools and the NAT were administered separately by blinded raters. The NAT and both the a- and i-ADL tools showed significant differences between HCs, MCI, and AD participants. Convergent validity showed moderate to strong significant correlations between the NAT, and a- and i-ADL tools (range -0.583 to -0.663; p < 0.01). Concurrent validity showed that the NAT (AUC 0.809-1.000) and the a- and i-ADL tools (AUC 0.739-0.964) presented comparable discriminatory accuracy (p = 0.0588). In contrast to prior studies comparing report-based and performance-based methods of assessing ADL, this study indicates that the NAT and the a- and i-ADL tools have strong convergent and concurrent validity, and appear to have similar discriminatory power in differentiating between HCs, MCI, and AD.

Performance-based resource allocation for higher education institutions in China

How to allocate limited resource to higher education institutions has always been a critical problem with significant social and economic relevance. Researchers and educational administrators have long proposed that resource allocation should be linked to performance. In this paper, we develop a performance-based method for a central planner to allocate research funding to different universities to better stimulate the research output. The method builds on existing works on resource allocation via efficiency analysis. The method takes multiple dimensions of research performance into account, including number of publications, number of patents, and revenue from knowledge transfer. We apply the method to a set of 64 major universities in China based on performance in 2014–2016. The application is particularly pertinent at the moment, since the Chinese government is developing a new funding program called the “double first-class” plan, which features performance-based funding as a central pillar of government funding.

Integrating quantitative defense-in-depth metrics into new reactor designs

Risk-informed, performance-based (RIPB) methods have progressed to the point where high-level guidance can be used to augment traditional, deterministic, nuclear safety design practices in areas important to nuclear reactor safety. This paper describes an approach for augmenting the traditional defense-in-depth (DID) qualitative approach with quantitative risk information from a plant-specific probabilistic risk assessment (PRA) in a way that is structured, can be applied on a consistent basis, and allows for clear acceptance criteria. Adding performance-based targets that should be achieved is expected to result in safer and more economical plant designs. Evaluations of DID can be conducted throughout the design process as well as in support of design certification and operating license applications to identify where defense protections could be enhanced or relaxed. Consistent with the United States Nuclear Regulatory Commission's policy statement encouraging greater use of PRA to improve safety decision making and regulatory efficiency, this scenario-based DID method can be used to evaluate changes and overall plant design as part of the normal design control process. Although the RIPB method presented in this paper was developed for application to advanced passive light water reactor designs, the metrics could be tailored to other reactor designs. This risk-informed approach to DID helps to ensure that public and worker risk insights are integrated into the design process holistically.

Prediction of aircraft safety incidents using Bayesian inference and hierarchical structures

Today, aviation is immersed in a shift from old-fashioned reactive and compliance-based safety approaches towards proactive and performance-based methods and tools. Stakeholders have to monitor, gather and analyse safety-related data and information in order to anticipate and predict actual and emerging safety risks. In this context safety analytics and statistics need to evolve to forecast future safety performances and risks.This research adopts an innovative statistical approach involving the use of Bayesian inference and Hierarchical structures to develop statistical estimation and prediction models with different complexities and objectives. The study develops and analyses five Bayesian models of increasing difficulty, two basic and three Hierarchical models, which allows us to explore safety incident data, efficiently identify anomalies, assess the level of risk, define an objective framework for comparing air carriers, and finally predict and anticipate incidents.