Synthetical condition assessment of long span suspension bridge based on closeness degree and FAHP

Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a mathematical model of a multi-objective assessment of a long span suspension bridge is set up. An example is given to show the procedure in the synthetical condition assessment of the Runyang Suspension Bridge, which includes the hierarchical division, the definition of factor weights and fuzzy membership functions, and the calculation of closeness degrees, etc. The assessment combines both the data from the health monitoring system and the manual tests. The classification of evaluation items as well as the calculation of deterministic and nondeterministic items is presented. Compared with the traditional method of point rating, this method can better describe the discreteness of monitoring data and the fuzziness in the condition assessment.

Assessing the Environmental Impact of Extensive Beef Production in Grazing Lands of Argentina

Because of environmental constraints,beef cattle was for more than a century the only viable farming option in the extensive semiarid and subhumid lands of Argentina and the main source of nutrients for humans as well.However,a growing concern and criticism have risen today about its possible negative impact on the climate and the environment.These worries tend to affect current public opinions,national policies,and international trade.Based on 40 beef cattle farms scattered across different semiarid and subhumid regions of Argentina,here we evaluated the impact of extensive cattle production on carbon,water,and nutrient pollution.Life-Cycle Assessment(LCA)and Land-Based Assessment(LBA)were the two approaches we used here to compare the environmental impact of beef production.While the environmental footprint(EF)resulting from LCA expresses the impact per unit of food,the environmental balance(EB),derived from LBA,aims at quantifying the impact per unit of land.As such,the EB considers both negative and positive impacts on the farm as an integrated system.Following standardized procedures,we evaluated EF and EB up to the farm gate,leaving aside delocalized post-farm impacts such as those of processing,packaging,and transportation that occur beyond the farm gate.In agreement with previous evidence,our results show that the EF tends to decrease as per-head production increases.Correlation coefficients and statistical significance were the following for carbon(R=−0.574;p<0.01),water(R=−0.561;p<0.01),and N(R=−0.704;p<0.01)and Phosphorus(P)pollution(R=−0.802;p<0.01)footprints.On the contrary,the EB seems to be highly sensitive,and as per-hectare beef production increases.Correlations were the following for carbon emissions(CE:R=0.955;p<0.01),water consumption(WC:R=0.822;p<0.01),nitrogen excretion(NE:R=0.948;p<0.01)and phosphorus excretion(PE:R=0.945;p<0.01).What our results suggest is that the notion of EF is useful to evaluate the environmental impact in intensive beef production systems,and the EB is suitable to assess the impact of the extensive ones.In practice,both approaches provide different perspectives on the environmental-impact problem and they should be complementary used.We concluded that the methodological rigidity of EF does not allow proper discrimination among farms in the extensive systems.On the contrary,the EB approach tended to be highly sensitive to detecting differences between individual farms and farmers,thus allowing the identification of successful options for extensive beef production in terms of public image,policy-making,and commercial opportunities.

Risk Assessment Framework and Algorithm of Power Systems Based on the Partitioned Multi-objective Risk Method

针对平均风险指标无法区分高损失-低概率事件及低损失-高概率事件的缺点,提出了电力系统的分割多目标风险分析框架。该框架将电力系统的风险状态细分为低损失、中等损失和高损失3个风险范围,并提出3个损失范围条件风险函数和条件风险概率的概念。采用经典的容量停运表模型,建立了这些条件期望指标的计算方法。对IEEE-RTS及TH-RTS2000系统进行了分割多目标风险评估,研究不同负荷水平下系统风险在3个损失范围的分布及转移情况,并分析损失分割点对系统风险的影响。通过分割多目标风险分析,风险分析者和决策者可以权衡系统的平均风险以及高、中、低损失范围的条件期望风险,从而对系统的风险状况有一个全面和深入的了解。

Application of uncertain type of AHP to condition assessment of cable-stayed bridges

In order to guarantee the safety service and life-span of long-span cable-stayed bridges, the uncertain type of analytic hierarchy process （AHP） method is adopted to access the bridge condition. The correlative theory and applied objects of uncertain type of AHP are introduced, and then the optimal transitive matrix method is chosen to calculate the interval number judgment matrix, which makes the weights of indices more reliable and accurate. Finally, with Harbin Songhua River Cable-Stayed Bridge as an example, an index system and an assessment model are proposed for the condition assessment of this bridge, and by using uncertain type of AHP, the weights of assessment indices are fixed and the final assessment results of the bridge are calculated, which proves the feasibility and practicability of this method. The application of this assessment method can provide the scientific basis for maintenance and management of long-span cable-stayed bridges.

Integrated Assessment of the Ecological Status of Bulgarian Lowland and Semi-Mountain Natural Lakes

This work focuses on an integrated approach for lake ecological status assessment, elaborated according to the requirements of the European Water Framework Directive (WFD). Data from five lowland and semi-mountain lakes in Bulgaria (Southeast Europe) collected from two years (2011-2012) form the basis for an integrated assessment and the definition of reference conditions. Several metrics were applied in combination, to classify lakes into five ecological status classes. Assemblages of aquatic organisms: phytoplankton, macrophytes and benthic macroinvertebrates, together with 11 supporting physico-chemical parameters were studied. The assessed unique conditions suggested that reference conditions of Bulgarian lakes have natural variability. This first baseline study illustrated specific cases within the lake types that should be assessed in details before providing standardized classification systems in compliance with the requirements of WFD.

The Acceptance and Use of Computer Based Assessment in Higher Education

Computer Based Assessment (CBA) is being a very popular method to evaluate students’ performance at the university level. This research aims to examine the constructs that affect students’ intention to use the CBA. The proposed model is based on previous technology models such as Technology Acceptance Model (TAM), Theory of Planned Behavior (TPB), and Unified Theory of Acceptance and Usage of Technology (TAUT). The proposed CBA model is based on nine variables: Goal Expectancy, Social Influence, Facilitating Conditions, Computer Self Efficacy, Content, Perceived Usefulness, Perceived Ease of Use, Perceived Playfulness, and Behavioral Intention. Data were collected using a survey questionnaire from 546 participants who had used the computer based exam system at the University of Jordan. Results indicate that Perceived Playfulness has a direct effect on CBA use. Perceived Ease of Use, Perceived Usefulness, Computer Self Efficacy, Social Influence, Facilitating Conditions, Content and Goal Expectancy have only indirect effects. The study concludes that a system is more likely to be used by students if it is playful and CBA is more likely to be playful when it is easy to use and useful. Finally, the studied acceptance model for computer based assessment explains approximately only 10% of the variance of behavioral intention to use CBA.

Analysis of Tectonic Conditions for Strong Earthquakes and Prediction of Seismic Risk of Seismogenic Fault Zones in the Northern Part of North China

The tectonic conditions for strong earthquakes are complicated in various aspects.The genetic conditions for strong earthquakes were studied from the angle of various disciplines.About 20 conditions belonging to different fields have been described by predecessors.In this paper,the authors try to study and evaluate all the tectonic condition factors for strong earthquakes by the methods of fuzzy mathematics and hierarchical analysis.Taking the northern part of North China as an example,the authors make a comprehensive digital analysis of all the quantitative and semi-quantitative tectonic factors.The credibility values of all strong earthquakes with different magnitudes are given after statistical analysis and calculation.Forty-one fault zones in the study region are quantitatively analyzed,and the potential seismogenic fault zones,maximum magnitude,and risk of earthquake occurrence in the near future are assessed.The result of synthetic evaluation,based on all tectonic conditions of different

Fuzzy comprehensive assessment of running condition for a large-scale centrifugal compressor set

A fuzzy comprehensive assessment method of running condition was constructed and applied to a large-scale centrifugal compressor set in a petrochemical corporation aiming at the monitoring and early warning of abnormal conditions in industry.The maximal information coefficient(MIC)correlation analysis of indexes was introduced to determine the independent indexes to be assessed,and the dynamic deterioration degree was calculated using the predicted independent indexes by the second-order Markov chain model.The fuzzy membership degree weighting method was employed to assess the running condition of all units in the set.Simple and direct radar chart was used to visualize condition assessment grades.Results showed that the proposed fuzzy comprehensive assessment method successfully assessed the running condition of the set.The constructed method achieved 10 min earlier alarm than the traditional threshold alarm occurred at the specific moment of00:44 on April 7 of 2018.The method would provide a valuable tool and have a wide engineering application in ensuring the safety and reliability of industrial production.

Condition assessment of structures under unknown support excitation

A new method is proposed to assess the condition of structures under unknown support excitation by simultaneously detecting local damage and identifying the support excitation from several structural dynamic responses. The support excitation acting on a structure is modeled by orthogonal polynomial approximations, and the sensitivities of structural dynamic response with respect to its physical parameters and orthogonal coefficients are derived. The identification equation is based on Taylor＇s first order approximation, and is solved with the damped least-squares method in an iterative procedure. A fifteen-story shear building model and a five-story three-dimensional steel frame structure are studied to validate the proposed method. Numerical simulations with noisy measured accelerations show that the proposed method can accurately detect local damage and identify unknown support excitation from only several responses of the structure. This method provides a new approach for detecting structural damage and updating models with unknown input and incomplete measured output information.

Quantitative assessment of flight safety under atmospheric icing conditions

A quantitative assessment method is proposed to sense the specific effects of atmospheric icing conditions on flight safety. A six degree-of-freedom computational flight dynamics model is used to study the effects of ice accretion on aircraft dynamics, and a pilot model is also involved. In order to investigate icing severity under different icing conditions, support vector regression is applied in establishing relationship between aircraft icing parameter and weather conditions. Considering the characteristics of aircraft icing accidents, a risk probability assessment model optimized by the particle swarm method is developed to measure the safety level. In particular, angle of attack is chosen as a critical parameter in this method. Results presented in the paper for a series of simulation show that this method captures the basic effects of atmospheric icing conditions on flight safety, which may provide an important theoretical reference for icing accidents avoidance.

Fast prediction of the mechanical response for layered pavement under instantaneous large impact based on random forest regression

The layered pavements usually exhibit complicated mechanical properties with the effect of complex material properties under external environment.In some cases,such as launching missiles or rockets,layered pavements are required to bear large impulse load.However,traditional methods cannot non-destructively and quickly detect the internal structural of pavements.Thus,accurate and fast prediction of the mechanical properties of layered pavements is of great importance and necessity.In recent years,machine learning has shown great superiority in solving nonlinear problems.In this work,we present a method of predicting the maximum deflection and damage factor of layered pavements under instantaneous large impact based on random forest regression with the deflection basin parameters obtained from falling weight deflection testing.The regression coefficient R^(2)of testing datasets are above 0.94 in the process of predicting the elastic moduli of structural layers and mechanical responses,which indicates that the prediction results have great consistency with finite element simulation results.This paper provides a novel method for fast and accurate prediction of pavement mechanical responses under instantaneous large impact load using partial structural parameters of pavements,and has application potential in non-destructive evaluation of pavement structure.

Assessment of Multiple Working Condition System Reliability with Agent-Based Simulation Method

The mission reliability assessment plays a great role in logistics planning and supporting resource optimization of complex system.But the current problem,which is difficult to solve,is how to model and analyze the characters of system reliability under the complex mission profile.In order to solve the problem,an agentbased simulation method was used to assess reliability for complex systems with various random working conditions.A multi-working condition simulation agent(MA)was designed and used to simulate the random transferring process of working conditions of system,and it cooperated with system simulation agents(SAs)and unit simulation agents(UAs)to realize system mission reliability(MR)simulation.Through simulation experiments,effect of multiple working conditions mission on the reliability of system was analyzed by comparing with the basic reliability condition.Feasibility and efficiency of the method were proved through simulation experiments of the case system.The research result provides a viable and useful method and a solution for MR analysis and assessment of complex systems in multi-working conditions,which can help to evaluate the reliability of operating system orienting to the practical mission and environment,and it is meaningful for the reliability analysis and the design of complex systems.

An Assessment of Indoor Acoustic Condition in Students Hostels within Obafemi Awolowo University, Nigeria

It has been hypothesized that objective assessment for building acoustic conditions only may not always be representative of the users’ perception in occupied indoor spaces. This study objectively and subjectively examined indoor acoustic condition in rooms within students’ hostels in Obafemi Awolowo University, Nigeria. The objective assessment considered the physical measurement of sound pressure level in the rooms in relation to the rooms’ physical characteristics like window to external wall area and window to floor area ratios. The subjective assessment considered the occupants’ perception of the acoustic condition in the rooms in relation to their personal characteristics like age, gender, body mass index, metabolic rate, and body skin area. The sound pressure level was measured in each of the randomly selected 44 rooms at 15 minute intervals between 7 hours and 19 hours daily through a period of eight weeks. The measurement was done with High Accuracy Digital Sound Noise Level Data Loggers placed at work plane at the centre of the rooms. The geometry of the rooms was documented through physical measurements. All the occupants of the selected rooms as well as the two adjoining rooms, amounting to 696 respondents, were purposively selected to fill a questionnaire regarding activities carried out in the rooms, the frequency of fenestration opening, the personal characteristics of the occupants and the rooms’ occupancy ratio. This study established a strong correlation between the objective and subjective assessments of the acoustic condition in the spaces. Moreover, out of all the occupants’ personal characteristics considered, it was the age that has a relationship with the occupants’ perception of the acoustic condition that is closest to significant level.The relationship between their perception and measured sound pressure level was slightly more pronounced among the male gender than the female with correlation coefficients of 0.115 and 0.096 respectively. This study concluded that none of the considered occupants’ personal characteristics can effectively predict their response to indoor acoustic condition in the spaces.

Using GIS and Kriging to Analyze the Spatial Distributions of the Health Risk of Indoor Air Pollution

Kriging is an interpolation technique that is used to estimate a variable at an unmeasured location from observed values at nearer locations. In this study, it is used to analyze the spatial distributions of the health risk of indoor air pollution. The study case is an air-conditioned office building that has 16 floors, located in Taipei, Taiwan. The Kriging method is used in drawing health risk maps on the basis of limited sample points and facilitates investigating the possible source of pollution.

GEOCHEMISTRY STUDY OF GOLD SILVER DEPOSITS IN THE MIDDLE UPPER PROTEROZOIC SUBERATHEM IN SOUTHERN QINLING METALLOGENETIC ZONE

According to Ihe combinations of mctallogcnetic elements and minerals assemblages,the Au-Ag deposits in the Middle-Upper Proterozoic Suberathcm of the middle of northern margin of Yangtze Platform could be classified into four types,(l)Au-Ag-Pb-Zn type,(2)Au-Ag-Te type,(3)Au-quartz vein type,(4)Au-Ag-Pb-Zn-Ba type.The Yangpin formation and the upper Dangyuhe subformation,which belong to Wudangshan group,are regarded as favorable strata for Au-Ag mineralization by systematic assessments for Au-Ag bearing ability of the strata,as well as the felsic rocks of Bikou group.The mctallogcnetic physicochemical conditions and the stable isotopic compositions(S.Pb,H.O,C)have been studied in this paper.The sources of metallogenetic materials,origins of fluids and genesis of various deposits have also been studied.

Review Article on Condition Assessment of Structures Using Electro-Mechanical Impedance Technique

Structural health monitoring(SHM)is a process for determination of presence,location,severity of damages and remaining life of the infrastructures.SHM is widely applied in aerospace,mechanical and civil engineering sys-tems to assess the conditions of structures to improve the operation,safety,serviceability and reliability,respec-tively.There are various SHM techniques for monitoring the health of structures such as global response based and local techniques.Damages occur in the structures due to its inability to withstand intended design loadings,physical environment and chemical environment.Therefore,damage identification is necessary to improve the durability of the structures for protection against catastrophic failure.The research paper is focused on elec-tro-mechanical impedance(EMI)technique which is one of the techniques based on smart materials.The smart materials are utilized for monitoring the health of the structures.These are used for damage determination and its quantification for the interrogated structures.Variation in admittance or impedance signature shows the existence of damage in the structures.Furthermore,the different statistical methods viz.,root mean square deviation(RMSD),mean absolute percentage deviation(MAPD),covariance(Cov),and correlation coefficient(CC)are used for the quantification of damage.Smart material such as piezoelectric materials,its properties and applica-tions are also considered.In this paper,the implementation of EMI technique based on different recent advances in smart materials and their appropriateness have been described.Subsequently,the reviewed investigations are significant for the monitoring of real-life infrastructures.The presented paper is the compact state-of-the-art for EMI technique which is used for SHM.This examination will be valuable to infrastructural health monitoring and engineering applications in respect to innovative research directions.

Application of Serum Apelin and MMP-9 in Evaluation of Silicosis and Their Correlation with Lung Function

[Objectives]This study was conducted to explore the combination of serum Apelin and MMP-9 in the assessment of silicosis and their correlation with lung function. [Methods] From January 2020 to January 2021, eight patients with silicosis(including 3, 2 and 3 patients with silicosis in stages I, II and III respectively) were selected as the observation group, and eight persons frees of silicosis were selected as the control group during the same period. All patients were detected for serum APJ endogenous ligand(Apelin) of G protein-coupled receptor, matrix metalloproteinase-9(MMP-9) and pulmonary function indexes. The levels of serum Apelin and MMP-9 and lung function in the two groups were compared, and the correlation between serum Apelin and MMP-9 indexes and lung function was analyzed. [Results] The serum Apelin and lung function in the observation group were lower than those in the control group, and the level of MMP-9 in the observation group was higher than that in the control group, and the differences were statistically significant(P<0.05). The MMP-9 index in patients with silicosis in stage III was higher than those in patients with silicosis in stage II and stage I, and the MMP-9 index in patients with silicosis in stage II was higher than that in patients with silicosis in stage I, and the differences were statistically significant(P<0.05). The serum Apelin and lung function indexes of patients with silicosis in stage III were lower than those of patients with silicosis in stage II and stage I, and the serum Apelin and lung function indexes of patients with silicosis in stage II were lower than those of patients with silicosis in stage I, and the differences were statistically significant(P<0.05). The correlation analysis showed a positive correlation between serum Apelin and lung function indexes, and a negative correlation between MMP-9 and lung function indexes. [Conclusions] A lower serum Apelin and a higher MMP-9 value in patients with silicosis indicate severer lung function impairment, and the combined detection of serum Apelin and MMP-9 is conducive to effective evaluation of the disease of silicosis. The serum Apelin index was negatively correlated with silicosis, and the level of MMP-9 was positively correlated with silicosis, which could provide a scientific basis for clinical diagnosis and treatment.

Assessing Future Flooding Risk in a Coastal Lagoon Using Hydrogeological Approaches and Analysis of the 2021 Flood Event: A Case Study of Tasi-Tolu Lagoon, Dili, Timor-Leste

This study aims to apply a hydrogeological approaches and analysis of the 2021 flood event of Tasi-Tolu Lagoon to achieve four specific goals. Firstly, the study seeks to determine the natural characteristics of the lagoon, which include factors such as size, depth, water quality, and ecosystem composition. Secondly, the influence of precipitation on the water volume in the lagoon will be examined. This analysis involves assessing historical rainfall patterns in the region, as well as the amount and frequency of precipitation during the 2021 flood event. Thirdly, the hydrogeologic and geologic conditions of the lagoon will be evaluated. This involves examining factors such as the type and structure of the soil and bedrock, the presence of aquifers or other underground water sources, and the movement of water through the surrounding landscape. Finally, the study seeks to assess the risk of future flooding in Tasi-Tolu Lagoon, based on the insights gained from the previous analyses. Overall, this study’s goal is to provide a comprehensive understanding of the hydrogeological factors that contribute to flooding in Tasi-Tolu Lagoon. This knowledge could be used to inform flood mitigation strategies or to improve our ability to predict and respond to future flooding events in the region.

Application of Voltage Response Method to Condition Assessment of Power Transformer

Power transformer is one of the most important equipment in the power system.Its operating condition affects the reliability of power supply directly.Therefore,in order to guarantee transformer operation safely and reliably,it is necessary to assess condition of power transformer accurately.Return voltage method based on voltage response measurements is still a new non-intrusive diagnosis method for internal insulation aging of transformer.In this paper the technique and application of return voltage measurement and some results of voltage response measurements of several transformers was introduced.Voltage response measurements were performed on various transformers with different voltage grades,various operating periods,different moisture contents and aging degrees on site.Derived moisture contents from return voltage measurement were compared with the corresponding moisture contents obtained from the analysis of oil samples.Based on on-site experiments and theoretical analysis,the criteria for insulation state of transformer are proposed.Moisture condition of transformer insulation can be determined by using return dominant time constant,and a good correlation between aging degree and the return voltage initial slopes of the aged transformers.Field test performed on several transformers,its interpretation of results are also presented,which proves that return voltage measurements can be used as a reliable tool for evaluating moisture content in transformer insulation.

Assessment of Structural Damage Condition Based on Fuzzy Pattern Recognition

This paper presents a new method of damage condition assessment that allows accommodating other types of uncertainties due to ambiguity, vagueness, and fuzziness that are statistically nondescribable. In this method, healthy observations are used to construct a fury set representing sound performance characteristics. Additionally, the bounds on the similarities among the structural damage states are prescribed by using the state similarity matrix. Thus, an optimal group fuzzy sets representing damage states such as little, moderate, and severe damage can be inferred as an inverse problem from healthy observations only. The optimal group of damage fuzzy sets is used to classify a set of observations at any unknown state of damage using the principles of fitzzy pattern recognition based on an approximate principle . This method can be embedded into the system of Structural Health Monitoring （SHM） to give advice about structural maintenance and life predictio comes from Reference [ 9 ] for damage pattern recognition is presented n. Finally, a case and discussed. The study, which compared result illustrates our method is more effective and general, so it is very practical in engineering.