Dynamic Assessment Method Research Articles

Evaluation of plantar pressure distributions in patients with anteriorcruciate ligament deficiency: preoperative and postoperative changes.

Anterior cruciate ligament (ACL) deficiency results in several kinematic changes in the lower extremities. The aim of this study is to define the plantar pressure parameters in ACL-deficient patients and to show the effect of ACL reconstruction on dynamic plantar pressure. Forty patients with unilateral ACL rupture and 40 healthy controls were included in this study. Dynamic plantar pressures of both groups were recorded by the EMED SF-2 system during level walking. Thirteen of the patients who had ACL reconstructions with hamstring autografts (HS group) were reevaluated at an average of 14.5 months following the ACL reconstructions. ACL-deficient patients had significantly lower hindfoot (P = 0.007) but higher midfoot pressure values (P = 0.03) on their ipsilateral foot compared to control group subjects. Ipsilateral hindfoot pressures were also found to be significantly lower than those of the contralateral foot (P = 0.001). Hindfoot pressure values of the HS group were increased in postoperative measurements (P = 0.01). ACL-deficient patients have altered plantar pressure distributions and ACL reconstructions restore these changes to normal. Pedobarography might be used as a practical method for dynamic functional assessment of ACL-deficient patients.

Numerical investigations on static and dynamic responses of reinforced concrete sub-assemblages under progressive collapse

To study the effect of blast pressure on structural resistance against progressive collapse under column removal scenario induced by contact detonation, and to investigate the development of catenary action within ultra-fast dynamic regime, a physics-based finite element model is developed in this paper. The model is first validated by a quasi-static test series on reinforced concrete sub-assemblages under middle column loss assumption and a blast test series using the same structural configurations. The sub-assemblage included a two-span beam, a middle column stub and two column stubs at both sides. Besides validations with sub-structure tests, some pull-out tests are also performed to verify the numerical models. After the verifications, parametric studies are conducted to investigate the influence of important dynamic and structural factors such as the boundary stiffness, damping ratio, and charge weight attached to the middle column. The study shows that under actual blast conditions, catenary action in sub-assemblages can be mobilised to prevent a structure from collapse even when the bottom longitudinal reinforcement in the bridging beam has already fractured. Moreover, stiffness of horizontal restraints plays an important role to mitigate disproportionate collapse in both static and blast conditions. A comparison is also made between nonlinear dynamic procedure and nonlinear static analysis incorporating simplified energy method for dynamic assessment. It is concluded that the simplified static approach in lieu of dynamic analysis can be considered as a conservative method for practical design purpose. Nonetheless, this method may over-estimate structural resistance if the localised damage is induced by a contact-detonation event.

Method for measuring settling phenomena by means of frequency domain instrumentation.

The paper deals with the analysis of settling phenomena that characterize the step response of digital to analog converters, amplifiers, and several other devices. Settling is described by means of a minimal second order model that is suitable to account for the distortion terms recognized in the signal spectrum. An alternative method for dynamic performance assessment of systems characterized by poor settling performance is then proposed. Thanks to the use of high bandwidth spectrum analyzers, the proposed method overtakes the limits characterizing the measurement approaches based on the use of time-domain instruments in the presence of modern ultra-wideband systems.

A Method for Dynamic Risk Assessment and Management of Rockbursts in Drill and Blast Tunnels

Focusing on the problems caused by rockburst hazards in deep tunnels, such as casualties, damage to construction equipment and facilities, construction schedule delays, and project cost increase, this research attempts to present a methodology for dynamic risk assessment and management of rockbursts in D&B tunnels. The basic idea of dynamic risk assessment and management of rockbursts is determined, and methods associated with each step in the rockburst risk assessment and management process are given, respectively. Among them, the main parts include a microseismic method for early warning the occurrence probability of rockburst risk, an estimation method that aims to assess potential consequences of rockburst risk, an evaluation method that utilizes a new quantitative index considering both occurrence probability and consequences for determining the level of rockburst risk, and the dynamic updating. Specifically, this research briefly describes the referenced microseismic method of warning rockburst, but focuses on the analysis of consequences and associated risk assessment and management of rockburst. Using the proposed method of risk assessment and management of rockburst, the occurrence probability, potential consequences, and the level of rockburst risk can be obtained in real-time during tunnel excavation, which contributes to the dynamic optimisation of risk mitigation measures and their application. The applicability of the proposed method has been verified by those cases from the Jinping II deep headrace and water drainage tunnels at depths of 1900–2525 m (with a length of 11.6 km in total for D&B tunnels).

The investigation of physiological data using the theory of complex systems

This paper presents a complex dynamic system assessment method based on Hankel matrix rank and inter-relationships between elements of the system evalution method. The possibilities of methods application for various physiological data measure and evaluation are introduced. The international project CareWare for portable sensors and systems development is briefly presented.

Dynamic Reliability Assessment for Multi-State Systems Utilizing System-Level Inspection Data

Traditional time-based reliability assessment methods evaluate the reliability of a multi-state system (MSS) from a population or a statistical perspective that the reliability of a system is computed purely based upon historical time-to-failure data collected from a large population of identical components or systems. These methods, however, fail to characterize the stochastic behaviors of a specific individual system. In this paper, by utilizing system-level observation history, a dynamic reliability assessment method for MSSs is put forth. The proposed recursive Bayesian formula is able to dynamically update the reliability function of a specific MSS over time by incorporating system-level inspection data. The dynamic reliability function, state probabilities, and remaining useful life distribution of an MSS in residual lifetime are derived for two common cases: the degradation of components follows a homogeneous continuous time Markov process, and a non-homogeneous continuous time Markov process. The effectiveness and accuracy of the proposed method are demonstrated via two numerical examples.

The Application of Dynamic Assessment: Is It Worth the Effort?

The emergence of Dynamic Assessment (DA) has been motivated by the inadequacy of conventional static tests to provide accurate information about the individuals' learning ability. To explore the effectiveness of Dynamic Assessment and conventional methods of teaching and assessing in writing, 45 female students were studied. These individuals were randomly assigned into two groups. To understand students' problems and needs better, individuals in both groups were asked to write reflective reports which mainly focused on their writing process. Analyzing the mean scores of these groups revealed the superiority of Dynamic Assessment. The students' scores in each group were also compared prior to the implementation of the treatment and after that, using two paired t-tests. The results revealed that unlike the conventional group, those in Dynamic Assessment group had improved their writing skills significantly. Such results implicitly revealed that writing reflective reports by itself cannot have any effect on the writing abilities of individuals. Some criteria for writing, as mentioned by the individuals in their reflective reports, were categorized: grammar, content, using appropriate and effective vocabulary, organization, spelling and capitalization. Further findings and implications for future research are discussed in the paper.

Engineering fracture assessment of FV520B steel impeller subjected to dynamic loading

The dynamic fracture assessment method applied to a cracked centrifugal impeller subjected to dynamic loading is the focus of this study. J-integral histories and loading rates at crack tips were evaluated by numerical simulation through ABAQUS and Zencrack software. True stress–strain relations, fracture mechanism and fracture toughness of the impeller material FV520B steel were investigated over a wide range of loading rates by experimental and theoretical methods. Fracture assessment with consideration to rate effects was then conducted based on the CEGB R6 procedure. The present method demonstrated advantages over existing methods evaluated by an equivalent static load.

Advanced Pattern Discovery-based Fuzzy Classification Method for Power System Dynamic Security Assessment

Dynamic security assessment (DSA) is an important issue in modern power system security analysis. This paper proposes a novel pattern discovery (PD)-based fuzzy classification scheme for the DSA. First, the PD algorithm is improved by integrating the proposed centroid deviation analysis technique and the prior knowledge of the training data set. This improvement can enhance the performance when it is applied to extract the patterns of data from a training data set. Secondly, based on the results of the improved PD algorithm, a fuzzy logic-based classification method is developed to predict the security index of a given power system operating point. In addition, the proposed scheme is tested on the IEEE 50-machine system and is compared with other state-of-the-art classification techniques. The comparison demonstrates that the proposed model is more effective in the DSA of a power system.

Method for Evaluation of Railway Dynamic Safety Based on 5M Model and Neural Network Algorithm

Traditional risk assessment methods, mainly static analysis, can’t anticipate the development trend and consequences of accidents. This paper firstly presents 5M safety model, combined with the characteristics of the rail transit safety assessment, including complexity, dynamic, ambiguity, etc. By using neural network algorithm, this paper proposes a method of railway safety dynamic assessment. Finally, the method is validated by comparing the output value of the model and the veritable value. The result indicated that it has advantages of real time and predictability.

Cerebral autoregulation index at high altitude assessed by thigh-cuff and transfer function analysis techniques.

What is the central question of this study? Whether cerebral autoregulation (CA) is impaired at high altitude and associated with acute mountain sickness remains controversial. We sought to compare two of the most common methods to assess dynamic CA in subjects who ascended to 3424 m and acclimatized. What is the main finding and its importance? We found that CA was reduced at 3424 m when assessed by the classic thigh-cuff inflation-deflation technique, but not when evaluated by transfer function analysis. These findings suggest that the cerebral vasculature of healthy individuals may become less able to buffer a large, abrupt drop in arterial blood pressure, while still maintaining the ability to regulate slow rhythmical oscillations, during periods of moderate hypoxaemia. The occurrence and implications of changes in cerebral autoregulation (CA) at high altitude are controversial and confounded by differences in methods used to assess CA. To compare two of the most common methods of dynamic CA assessment, we studied 11 young, healthy sea-level residents (six females and five males; 20.5 ± 2.3 years old) as they ascended to 3424 m and acclimatized over 13 days. A common autoregulation index (ARI) was calculated from the following: (i) transfer function analysis (TFA ARI) of resting oscillations in arterial blood pressure (ABP; finger plethysmography) and middle cerebral artery blood velocity (MCAv; transcranial Doppler); and (ii) MCAv responses following large, abrupt reductions in ABP using the classic thigh-cuff technique (Cuff ARI). Symptoms of acute mountain sickness (AMS) were monitored using the Lake Louise AMS Questionnaire. Cuff ARI scores decreased (P = 0.021) as subjects ascended from low (4.7 ± 1.5) to high altitude (3.2 ± 1.6) and did not change after 13 days of acclimatization (2.9 ± 1.3). The TFA ARI scores were not affected by ascent or acclimatization to 3424 m. Neither Cuff nor TFA ARI scores were correlated with AMS symptoms. These findings suggest that the cerebral vasculature of healthy individuals may become less able to buffer large step changes in ABP, while still maintaining the ability to regulate slow rhythmical oscillations, during periods of moderate hypoxaemia. Given the inherent differences in the autoregulatory stimulus between methods, multiple assessment techniques may be needed to clarify the implications of changes in cerebrovascular regulation at high altitude.

Dynamic successive assessment method of water environment carrying capacity and its application

Water environment carrying capacity (WECC) is an important foundation of sustainable socioeconomic development and may be affected by many factors such as water resources, water quality, economy, population and environmental protection. This article focuses on the temporal and spatial variability of WECC to explore a method of dynamic successive assessment. First, the Pressure-State-Response (PSR) framework is used to develop a systematic and causal indicator system representing the three aspects of water environment pressure carrying capacity (WEPCC), water environment state carrying capacity (WESCC) and water environment response carrying capacity (WERCC). The Variable Fuzzy Pattern Recognition (VFPR) model and an analytic hierarchy process (AHP) model are combined to successively and dynamically assess WEPCC, WESCC and WERCC, and after that the weighting method is used to calculate WECC. Furthermore, WECC is divided into 27 classes on the basis of WEPCC, WESCC and WERCC contributions. The proposed method is applied to the dynamic successive assessment of WECCs in China, including inter-province comparisons. The results show that the dynamic successive WECC assessment method is reasonable, and it can be used not only to accurately understand the changes of WECC through time but also to distinguish qualitative differences masked by similar WECC values.

Correlation Between Scapular Dyskinesis Test and Lateral Scapular Slide Test in Scapular Assessment

Objectives:Alterations of the normal position or any abnormal motion of the scapula during active motions of shoulder is termed Scapular Dyskinesis (SD). SD is quite common in overhead athletes with or without shoulder pain. In addition to overhead athletes, SD has also been identified in healthy, asymptomatic individuals. Although there are several proposed methods to identify SD, there are two common methods used in clinical practice; as Lateral Scapular Slide Test (LSST) and Scapular Dyskinesis Test (SDT). SDT was developed as a dynamic functional test after the development of LSST which is a static measurement. SDT has also relatively higher reliability than LSST. In the 2013 consensus statement from ‘scapular summit’, SDT was recommended as a simple and reliable method for scapular assessment because of being a dynamic functional assessment method. The purpose of this study was to investigate the correlation of these two observational tests in asymptomatic populationMethods:Eighty-three healthy participants (mean age 21.74±2.3 years, 166 arms, 32 Female-51 Male) were recruited. Participants were eligible if they were ≥18 years of age, having active full shoulder motion, and who have no health problem to hinder them from participate. Individuals with symptoms produced by cervical spine motion, impingement syndrome, frozen shoulder, shoulder instability and a history of shoulder fracture/surgery were excluded. All participants performed SDT and LSST in a random order. Pearson's chi-squared test was used for statistical analysis.Results:SDT detected SD in 44 participants (53%), LSST detected SD in 30 participants (36%). 20 participants (24%) determined as having SD in both tests. There was a moderate significant correlation between SDT and LSST (p=0.000, Pearson Chi-Square value=32.856, Phi=0.445).Conclusion:SDT and LSST have moderate correlation in identifying SD. In recent years, it is suggested that scapula shouldn’t be assessed in static positions/postures. Although both SDT and LSST show the presence of SD, they don’t evaluate SD in the same way because of the fact that LSST is a static assessment method whereas SDT is a dynamic method. Furthermore, SDT has higher reliability rather than other static assessment methods. Moderate correlation between these two tests may not always provide compatible outcome. For these reasons, we don’t recommend the use of LSST solely or instead of SDT in examination of SD. LSST’s complementary role in determination of SD with other assessment methods is arguable due to reliability issues. Optimal observational assessment algorithm in determination of SD should be investigated in future studies.

Indocyanine green plasma disappearance rate as dynamic liver function test in critically ill patients.

Indocyanine green (ICG) is a water-soluble fluorescent dye that is bound to plasma protein when administered intravenously. Removal of ICG from the blood depends on hepatic blood flow, function of the parenchymal cells and biliary excretion. ICG elimination is described as a useful dynamic liver function test. In this review, we looked at the most recent literature to clarify why ICG is useful in critically ill patients, the validity of the ICG plasma disappearance rate (ICG-PDR) measured transcutaneously and whether ICG-PDR has any prognostic value. In conclusion, measuring ICG-PDR is a valuable method for dynamic assessment of liver function, and is found to be a valuable prognostic tool in predicting survival for septic patients, patients presenting with acute liver failure and critically ill patients.

The ESPA (Enhanced Structural Path Analysis) method: a solution to an implementation challenge for dynamic life cycle assessment studies

By analyzing the latest developments in the dynamic life cycle assessment (DLCA) methodology, we identify an implementation challenge with the management of new temporal information to describe each system we might want to model. To address this problem, we propose a new method to differentiate elementary and process flows on a temporal level, and explain how it can generate temporally differentiated life cycle inventories (LCI), which are necessary inputs for dynamic impact assessment methods. First, an analysis of recent DLCA studies is used to identify the relevant temporal characteristics for an LCI. Then, we explain the implementation challenge of handling additional temporal information to describe processes in life cycle assessment (LCA) databases. Finally, a new format of temporal description is proposed to minimize the current implementation problem for DLCA studies. A new format of process-relative temporal distributions is proposed to obtain a temporal differentiation of LCA database information (elementary flows and product flows). A new LCI calculation method is also proposed since the new format for temporal description is not compatible with the traditional LCI calculation method. Description of the requirements and limits for this new method, named enhanced structural path analysis (ESPA), is also presented. To conclude the description of the ESPA method, we illustrate its use in a strategically chosen scenario. The use of the proposed ESPA method for this scenario reveals the need for the LCA community to reach an agreement on common temporal differentiation strategies for future DLCA studies. We propose the ESPA method to obtain temporally differentiated LCIs, which should then require less implementation effort for the system-modeling step (LCA database definition), even if such concepts cannot be applied to every process.

Talent identification in Hungary: From identification to investigation

This article provides an outline of talent identification practices and challenges in Hungary. First, it gives a summary of gifted education in the country; then the general challenges of talent identification are introduced: difficulties of defining talent, talent as potential, environmental factors, the role of perseverance and motivation, and individual variety. Later, recent Hungarian identification practices are shown, followed by a summary and a conclusion about how our identification practice should be developed into an investigation of individual characetristics. We propose stronger focus on the use of cognitive profile tests, investigation of interest-based characteristics, the use of observation and dynamic assessment methods, teacher nomination and emphasizing the need for effort. The focus from identification toward investigation exploring individual needs and characteristics to provide the most appropriate pathway for development in the 21 st century seems to be

Risk assessment for sustainable food security in China according to integrated food security—taking Dongting Lake area for example

Integrated food security covers three aspects: food quantity security, food quality security, and sustainable food security. Because sustainable food security requires that food security must be compatible with sustainable development, the risk assessment of sustainable food security is becoming one of the most important issues. This paper mainly focuses on the characteristics of sustainable food security problems in the major grain-producing areas in China. We establish an index system based on land resources and eco-environmental conditions and apply a dynamic assessment method based on status assessments and trend analysis models to overcome the shortcomings of the static evaluation method. Using fuzzy mathematics, the risks are categorized into four grades: negligible risk, low risk, medium risk, and high risk. A case study was conducted in one of China's major grain-producing areas: Dongting Lake area. The results predict that the status of the sustainable food security in the Dongting Lake area is unsatisfactory for the foreseeable future. The number of districts at the medium-risk range will increase from six to ten by 2015 due to increasing population pressure, a decrease in the cultivated area, and a decrease in the effective irrigation area. Therefore, appropriate policies and measures should be put forward to improve it. The results could also provide direct support for an early warning system-which could be used to monitor food security trends or nutritional status so to inform policy makers of impending food shortages-to prevent sustainable food security risk based on some classical systematic methods. This is the first research of sustainable food security in terms of risk assessment, from the perspective of resources and the environment, at the regional scale.

Future Directions in Non-Invasive Measurements of Tear Film Surface Kinetics

To review the methods for dynamic, non-invasive, and objective assessment of tear film surface quality and to outline their current state-of-the-art and their future potential. Among the methods available, high-speed videokeratoscopy, lateral shearing interferometry, and dynamic wavefront sensing are being considered. The principles of operations, their advantages and disadvantages, and limitations of each method are being outlined. The possible future directions of each method are also discussed. To gain a better understanding of tear film, its structure and function, it is essential to combine macroimaging technologies with those focusing on tear film microstructure. In this way, one can envisage a clinical device that could help, in future, early diagnosis of dry eye syndrome and development of better materials for contact lenses and eye lubricants.

Dynamic risk assessment of oil spill scenario for Three Gorges Reservoir in China based on numerical simulation

A novel method for dynamic risk assessment of oil spill accidents based on numerical simulation was presented in this paper. The dynamic risk assessment model was developed consisting of a comprehensive list of caused consequences like environmental damage, asset loss, health impact and social effect as well as emergency actions preventing these losses. Contributing events in the Mater Logic Diagram (MLD) of the dynamic risk assessment model were valued based on the simulated evolvement of oil contaminants under spill scenario on quasi-static fluid, which was obtained by coupling an oil spill model with hydrodynamic module in Jialing river of Three Gorges Reservoir in China after the impoundment of the reservoir to 175m water level in 2010. Calculated result of dynamic risk as grade IV indicated that the assessed oil spill was not as catastrophic as we thought because of the slow transport of oil fractions on water surface and absence of dispersed oil in water body due to the quasi-static fluid, very gentle wind and effective emergency actions, as well as by the reason that rare agriculture or industrial crops exist in spill adjacent area.

A new dynamic security enhancement method via genetic algorithms integrated with neural network based tools

In this paper, a new dynamic security assessment and generation rescheduling method utilizing genetic algorithms (GAs) which are integrated with probabilistic neural networks (PNNs) and adaptive neuro fuzzy inference systems (ANFISs) is proposed for the preventive control of large power systems against transient instabilities. By the proposed approach, PNNs are employed in a feasible manner to calculate the security regions accurately during the assessment and control. The security constrained generation rescheduling is implemented through a GA which optimizes the total fuel cost or the generation shifting during the preventive control. The steady-state solutions of the variables required for the GA are smoothly performed by the use of an ANFIS. The proposed methods are demonstrated on the 17-generator 163-bus Iowa power system and on the 50-generator 145-bus IEEE test system successfully and the effectiveness of the approaches is discussed.