Remaining Useful Life Model and Assessment of Mechanical Products: A Brief Review and a Note on the State Space Model Method

The remaining useful life(RUL) prediction of mechanical products has been widely studied for online system performance reliability, device remanufacturing, and product safety(safety awareness and safety improvement). These studies incorporated many di erent models, algorithms, and techniques for modeling and assessment. In this paper, methods of RUL assessment are summarized and expounded upon using two major methods: physics model based and data driven based methods. The advantages and disadvantages of each of these methods are deliberated and compared as well. Due to the intricacy of failure mechanism in system, and di culty in physics degradation observation, RUL assessment based on observations of performance variables turns into a science in evaluating the degradation. A modeling method from control systems, the state space model(SSM), as a first order hidden Markov, is presented. In the context of non-linear and non-Gaussian systems, the SSM methodology is capable of performing remaining life assessment by using Bayesian estimation(sequential Monte Carlo). Being e ective for non-linear and non-Gaussian dynamics, the methodology can perform the assessment recursively online for applications in CBM(condition based maintenance), PHM(prognostics and health management), remanufacturing, and system performance reliability. Finally, the discussion raises concerns regarding online sensing data for SSM modeling and assessment of RUL.

Agreement and conversion formula between mini-mental state examination and montreal cognitive assessment in an outpatient sample

AIM To explore the agreement between the mini-mental state examination(MMSE) and montreal cognitive assessment(Mo CA) within community dwelling older patients attending an old age psychiatry service and to derive and test a conversion formula between the two scales.METHODS Prospective study of consecutive patients attending outpatient services.Both tests were administered by the same researcher on the same day in random order.RESULTS The total sample(n = 135) was randomly divided into two groups.One to derive a conversion rule(n = 70),and a second(n = 65) in which this rule was tested.The agreement(Pearson's r) of MMSE and Mo CA was 0.86(P < 0.001),and Lin's concordance correlation coefficient(CCC) was 0.57(95%CI:0.45-0.66).In the second sample Mo CA scores were converted to MMSE scores according to a conversion rule from the first sample which achieved agreement with the original MMSE scoresof 0.89(Pearson's r,P < 0.001) and CCC of 0.88(95%CI:0.82-0.92).CONCLUSION Although the two scales overlap considerably,the agreement is modest.The conversion rule derived herein demonstrated promising accuracy and warrants further testing in other populations.

Fortifying Smart Grids: A Holistic Assessment Strategy against Cyber Attacks and Physical Threats for Intelligent Electronic Devices

Intelligent electronic devices(IEDs)are interconnected via communication networks and play pivotal roles in transmitting grid-related operational data and executing control instructions.In the context of the heightened security challenges within smart grids,IEDs pose significant risks due to inherent hardware and software vulner-abilities,as well as the openness and vulnerability of communication protocols.Smart grid security,distinct from traditional internet security,mainly relies on monitoring network security events at the platform layer,lacking an effective assessment mechanism for IEDs.Hence,we incorporate considerations for both cyber-attacks and physical faults,presenting security assessment indicators and methods specifically tailored for IEDs.Initially,we outline the security monitoring technology for IEDs,considering the necessary data sources for their security assessment.Subsequently,we classify IEDs and establish a comprehensive security monitoring index system,incorporating factors such as running states,network traffic,and abnormal behaviors.This index system contains 18 indicators in 3 categories.Additionally,we elucidate quantitative methods for various indicators and propose a hybrid security assessment method known as GRCW-hybrid,combining grey relational analysis(GRA),analytic hierarchy process(AHP),and entropy weight method(EWM).According to the proposed assessment method,the security risk level of IEDs can be graded into 6 levels,namely 0,1,2,3,4,and 5.The higher the level,the greater the security risk.Finally,we assess and simulate 15 scenarios in 3 categories,which are based on monitoring indicators and real-world situations encountered by IEDs.The results show that calculated security risk level based on the proposed assessment method are consistent with actual simulation.Thus,the reasonableness and effectiveness of the proposed index system and assessment method are validated.

Present state,basic theories,methods and progresses of investigation and assessment on marine hazardous geology in China

The achievement progresses of investigation and studies on marine hazardous geology are summarized and presentsd in the late 20 century in China. The importance, research value and present-day studies of marine hazardous geology, a newly developing branch of geoscience, are well expatiated. Several often confused concepts and theories are explained and redefined here. The comment on the means of investigations, assessment of marine hazardous geology, as well as its evolution, innovation, existing questions and future tasks are also introduced and presented. The concepts of 'hazard geology', geohazard', 'map of marine hazard geology', 'integrated evaluaton on seafloor stablity' are respectively discussed, including their definition, research objects, methods and contents. The types and classification of marine hazardous geology, principles and methods of marine hazardous geology map compilation, the assessment methods and models of marine hazardous geology environment and seafloor stability and so on are also discussed.

Quantum Risk Assessment Model Based on Two Three-Qubit GHZ States

With the acceleration of the construction of quantum communication networks,scholars have proposed different quantum communication protocols for different application scenarios.However,few scholars pay attention to the risk assessment process before communication.In this paper,we propose a novel quantum risk assessment model based on quantum teleportation technology with two three-qubit GHZ states.Only by using Bell states measurements(BSMs)and two-qubit projective measurements(PJMs),the communicators can recovery any arbitrary two-qubit state.This protocol can transmit two-dimension risk assessment factors with better security performance.On the one hand,more sufficient evaluation factors allow the two communicating parties to more objectively evaluate the risk level of communication with the other party,and on the other hand,it also improves the qubit efficiency of the protocol.Moreover,we introduce the third party in this scheme can be semi-trusted,which must be full-trusted in our previous work.This change can reduce the dependence of the communication parties on the third-party organization and improve the privacy of communication.The security analysis shows that this scheme can resist internal and external attacks,and the quantum circuit diagrams also prove that our protocol is physically easier to implement.

A Condition States Assessment System for Concrete Bridges Using Neural Networks

Due to continuing aging and heavy utilization of many bridges and the limited available funds, the importance of proper bridge condition state assessment has risen recently, which is the crucial point for rational decision-making on MR&R activities. This paper presents a prototype of the concrete bridge condition state assessment system (CBCSAS) with the following sub-modules: inspection, parameter recognition, structural assessment, main cause identification and priority-to-action. And multi-layer neural networks, which may combine with fuzzy set theory or not, are performed to realize the structural assessment with embedding expert knowledge into the assessment system.

Exploitable wave energy assessment based on ERA-Interim reanalysis data—A case study in the East China Sea and the South China Sea

Wave energy resources assessment is a very important process before the exploitation and utilization of the wave energy. At present, the existing wave energy assessment is focused on theoretical wave energy conditions for interesting areas. While the evaluation for exploitable wave energy conditions is scarcely ever performed. Generally speaking, the wave energy are non-exploitable under a high sea state and a lower sea state which must be ignored when assessing wave energy. Aiming at this situation, a case study of the East China Sea and the South China Sea is performed. First, a division basis between the theoretical wave energy and the exploitable wave energy is studied. Next, based on recent 20 a ERA-Interim wave field data, some indexes including the spatial and temporal distribution of wave power density, a wave energy exploitable ratio, a wave energy level, a wave energy stability, a total wave energy density, the seasonal variation of the total wave energy and a high sea condition frequency are calculated. And then the theoretical wave energy and the exploitable wave energy are compared each other; the distributions of the exploitable wave energy are assessed and a regional division for exploitable wave energy resources is carried out; the influence of the high sea state is evaluated. The results show that considering collapsing force of the high sea state and the utilization efficiency for wave energy, it is determined that the energy by wave with a significant wave height being not less 1 m or not greater than 4 m is the exploitable wave energy. Compared with the theoretical wave energy, the average wave power density, energy level, total wave energy density and total wave energy of the exploitable wave energy decrease obviously and the stability enhances somewhat. Pronounced differences between the theoretical wave energy and the exploitable wave energy are present. In the East China Sea and the South China Sea, the areas of an abundant and stable exploitable wave energy are primarily located in the north-central part of the South China Sea, the Luzon Strait, east of Taiwan, China and north of Ryukyu Islands; annual average exploitable wave power density values in these areas are approximately 10-15 kW/m; the exploitable coefficient of variation （COV） and seasonal variation （SV） values in these areas are less than 1.2 and 1, respectively. Some coastal areas of the Beibu Gulf, the Changjiang Estuary, the Hangzhou Bay and the Zhujiang Estuary are the poor areas of the wave energy. The areas of the high wave energy exploitable ratio is primarily in nearshore waters. The influence of the high sea state for the wave energy in nearshore waters is less than that in offshore waters. In the areas of the abundant wave energy, the influence of the high sea state for the wave energy is prominent and the utilization of wave energy is relatively difficult. The developed evaluation method may give some references for an exploitable wave energy assessment and is valuable for practical applications.

Multi-indicator assessment of water environment in government environmental auditing

This study focused on a multi-indicator assessment methodology for governmental environmental auditing of water protection programs. The environmental status of Wuli Lake in China was assessed using the global indicators （driver-status-response） developed by the Commission on Sustainable Development, and four additional indicators proposed by the author： water quality, pollution load, aquatic ecosystem status, and lake sediment deposition. Various hydrological, chemical, biological and environmental parameters were used to estimate the values of the indicators for assessment of environmental status of the lake based on time series data sets for twenty years. The indicators proposed can be customized to meeting the needs for particular assessment of water protection programs. This method can be used to evaluate the performance of national environmental protection programs and provide technical support for environmental auditors.

A Network Security Risk Assessment Method Based on a B_NAG Model

Computer networks face a variety of cyberattacks.Most network attacks are contagious and destructive,and these types of attacks can be harmful to society and computer network security.Security evaluation is an effective method to solve network security problems.For accurate assessment of the vulnerabilities of computer networks,this paper proposes a network security risk assessment method based on a Bayesian network attack graph(B_NAG)model.First,a new resource attack graph(RAG)and the algorithm E-Loop,which is applied to eliminate loops in the B_NAG,are proposed.Second,to distinguish the confusing relationships between nodes of the attack graph in the conversion process,a related algorithm is proposed to generate the B_NAG model.Finally,to analyze the reachability of paths in B_NAG,the measuring indexs such as node attack complexity and node state transition are defined,and an iterative algorithm for obtaining the probability of reaching the target node is presented.On this basis,the posterior probability of related nodes can be calculated.A simulation environment is set up to evaluate the effectiveness of the B_NAG model.The experimental results indicate that the B_NAG model is realistic and effective in evaluating vulnerabilities of computer networks and can accurately highlight the degree of vulnerability in a chaotic relationship.

Big data assessment on the operating characteristics of on-line taxis and thoughts on relevant policies

A double-dimensional big data assessment method on the characteristics of on-line taxi traffic operation is proposed to provide a scientific basis for carrying out the taxi industry reform and standardizing the on-line taxi hailing management work. Taking Shenzhen as an example, multi- source data such as on-line taxi license plate data, plate identification data and taxi （including on-line taxis） operation data are combined with the results of the stated preference （SP） survey on taxi operating characteristics to assess the overall operation characteristics of on-line taxis. The results show that the current on-line taxis in Shenzhen can be divided into three categories, that is, full-time on-line taxis, non- active on-line taxis and part-time on-line taxis, accounting for 4%, 55%, and 41%, respectively, of the total quantity. In terms of the characteristics of space-time operations, full-time on-line taxis have similar operating characteristics as those of traditional taxis; the operation of non-active on-line taxis and part-time on-line taxis coincides with commuting requirements during morning and evening peak hours. However, part-time on-line taxis operate for a much longer time period at night. Due to the convenient hailing and favorable price, on-line taxis have a significant impact on trip modes of citizens; and the substitution eflbct of on-line taxis on traditional buses and cruising taxis is obvious. It is beneficial for helping the government departments to objectively understand the development law of the on-line taxi industry and providing decision reference for the formulation of relevant management policies during the critical development stage of on-line taxi industry.

Assessing Strategy of Power Transformers Insulation State Based on Part-division and Entropy Method

Failure mechanisms of power transformers are complex and uncertain; it is difficult to determine index weights of insulation state. Therefore, it is a challenge to acquire an accurate assessment of insulation state of power transformers. In this paper, an assessing strategy for transformer insulation is proposed base on part-division of transformer and a comprehensive weight determination method. An index system of transformer is established on the basis of part-division of transformer. Each index’s weight is consisted of two parts, the constant weight and the variable weight, which are determined by improved analytic hierarchy process (AHP) and entropy method respectively. Af- ter categorizing insulation state into four levels and standardizing assessing indexes, a Cauchy membership function is forged, and a fuzzy algorithm is employed to simulate the uncertainty of the insulation state. Finally, a confidence criterion is employed to perform part-division based condition assessment of transformer. Case studies reveal that the proposed assessing strategy method is effective, convenient, and practical; with the new strategy, potential failures of transformers can be forecasted and insulation state of transformer parts can also be as- sessed. Furthermore, the assessing results can be used to guide condition-based maintenance.

Mental Health Assessment of Elderly People Attending Geriatric Clinic in Medical City

Background: Worldwide elderly population and their life expectancy are increasing gradually. Longevity in most cases brings down poorer health as well as functional status. Thus, it is necessary to understand the problems as well as social, psychological, and medical needs of elderly people in order to plan their optimal care. Objectives: To assess the mental health status (depression and memory state) of elderly people attending Geriatric clinic in medical city, and to determine the influence of some sociodemographic factors on elderly mental health status. Subjects and Method: A cross-sectional study was conducted among elderly people aged 60 years and more who attended geriatric clinic of medical city in Baghdad, from 1st of April to the end of June 2015. Special questionnaire form had been used for data collection via direct interview. The evaluation of the mental state was performed by using modified version of Wechsler Memory Scale and geriatric depression scale. Results: A total of 400 elderly persons were enrolled in the study, 109 (27.3%) of them had impaired memory. The analysis of data revealed that the age and marital status had statistical significant association with memory state. Nearly three quarter (72.8%) of study group had depression according to geriatric depression scale. The majority of studied women had depression (90%), and the same percentage was observed among widowed elders joining in the study.

A Brief Clinical Assessment of Cognitive Deficit with Impaired Daily Living Functioning in Parkinson’s Patients with and without Dementia

Cognitive decline in Parkinson’s disease (PD) is defined as dementia which affects activities of daily living (ADL) function. Dementia is one of the recognized issues in the treatment of Parkinson’s disease patients (PDP) as it is becoming a major contributor to morbidity. The objective of our study was to evaluate the cognitive decline in Parkinson’s disease patients (PDP) and the influence of cognition on daily living function deterioration in cognitively impaired and cognitively unimpaired PDP. Cognitively impaired PDP (n = 24), and cognitively unimpaired PDP (n = 16) were administered MoCA and MMSE performance based tests for cognitive measurements and Alzheimer’s Disease Cooperative Study Activities of Daily Living Inventory (ADCS-ADL) to determine everyday functioning. The significances of MoCA and MMSE among cognitively impaired PDP and cognitively unimpaired PDP in univariant analysis were P < 0.001 and P < 0.05. In partial correlation, MoCA was strongly related to ADL function as compare to MMSE (r = 0.623, P = 0.001). Cognitively impaired PDP showed significantly lower score on visuo-construction and attention. Among all variables of MoCA domains, attention is strongly associated with instrumental activity daily living (IADL) scores (logistic regression coefficient = 0.672, P = 0.01). These results suggest that dementia affects daily living performances especially the IADL tasks like attention and execution. Therefore, the assessment of complex daily activities particularly IADL is probably useful for the diagnosis of early stage cognitive impairment in PDP. Further MMSE test is less sensitive than MoCA for detecting significant cognitive decline in PDP and impaired attention is an important determinant of ADL functions in cognitively impaired PDP.

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.

Geologic characteristics,exploration and production progress of shale oil and gas in the United States:An overview

We present a systematic summary of the geological characteristics,exploration and development history and current state of shale oil and gas in the United States.The hydrocarbon-rich shales in the major shale basins of the United States are mainly developed in six geological periods:Middle Ordovician,Middle-Late Devonian,Early Carboniferous(Middle-Late Mississippi),Early Permian,Late Jurassic,and Late Cretaceous(Cenomanian-Turonian).Depositional environments for these shales include intra-cratonic basins,foreland basins,and passive continental margins.Paleozoic hydrocarbon-rich shales are mainly developed in six basins,including the Appalachian Basin(Utica and Marcellus shales),Anadarko Basin(Woodford Shale),Williston Basin(Bakken Shale),Arkoma Basin(Fayetteville Shale),Fort Worth Basin(Barnett Shale),and the Wolfcamp and Leonardian Spraberry/Bone Springs shale plays of the Permian Basin.The Mesozoic hydrocarbon-rich shales are mainly developed on the margins of the Gulf of Mexico Basin(Haynesville and Eagle Ford)or in various Rocky Mountain basins(Niobrara Formation,mainly in the Denver and Powder River basins).The detailed analysis of shale plays reveals that the shales are different in facies and mineral components,and"shale reservoirs"are often not shale at all.The United States is abundant in shale oil and gas,with the in-place resources exceeding 0.246×10^(12)t and 290×10^(12)m^(3),respectively.Before the emergence of horizontal well hydraulic fracturing technology to kick off the"shale revolution",the United States had experienced two decades of exploration and production practices,as well as theory and technology development.In 2007-2023,shale oil and gas production in the United States increased from approximately 11.2×10^(4)tons of oil equivalent per day(toe/d)to over 300.0×10^(4)toe/d.In 2017,the shale oil and gas production exceeded the conventional oil and gas production in the country.In 2023,the contribution from shale plays to the total U.S.oil and gas production remained above 60%.The development of shale oil and gas has largely been driven by improvements in drilling and completion technologies,with much of the recent effort focused on“cube development”or“co-development”.Other efforts to improve productivity and efficiency include refracturing,enhanced oil recovery,and drilling of“U-shaped”wells.Given the significant resources base and continued technological improvements,shale oil and gas production will continue to contribute significant volumes to total U.S.hydrocarbon production.

Ecosystem Health Assessment in Wuli Lake

Using the method of trophic state-composite index (TSI-CI ) and the 12 months of monitoring data in 2010,we carry out initial exploration of the status of ecosystem health in Wuli Lake. First,we select four indicators,Chla,SD,TP and TN,to conduct trophic state assessment using weighted index method; then after selecting physical,chemical and biological indicators to conduct nondimensionalization processing,we calculate the composite index and conduct comprehensive assessment. The results show that in 2010,the status of ecosystem health in Wuli Lake was the best in July,worst in August; when the composite trophic state indicators with Chla as the representative increase or decrease significantly and cross different nutritional grades,TSI will significantly deviate from CI,and the relationship between the two in the other time is not prominent.

面向抗震韧性评价的型钢混凝土柱易损性函数

为满足型钢混凝土(steel reinforced concrete,SRC)结构地震损失评估及抗震韧性评价的需求,建立SRC柱构件的地震易损性函数十分关键。本文首先基于文献调研,结合JGJ 138—2016《组合结构设计规范》,从国内外文献中筛选了227榀拟静力循环加载的SRC柱,建立标准化的SRC柱试验数据库。其次,考虑失效模式的差异性,将构件分为延性SRC柱和偏脆性SRC柱,并给出了不同类别的构件损伤等级划分标准及对应的修复方法。然后,以位移角为工程需求参数,分别提取了各构件对应不同损伤等级的位移角限值,采用FEMA P-58方法,建立了不同类别的SRC柱在各损伤等级下的易损性函数。最后,给出了与GB/T 38591—2020《建筑抗震韧性评价标准》相容的易损性函数参数表,并分析了抗震等级和轴压比对SRC柱易损性函数参数及易损性曲线的影响。最终,通过分析一幢型钢混凝土框架结构办公楼的抗震韧性,说明了所提出的易损性函数在抗震韧性评价中的作用。

基于模糊层次综合分析的残损状态纯木结构安全评估方法

现存古建筑大多带伤服役,体内残损状态复杂多样,且对古建筑进行的加固维修与原有残损对结构本体的安全性能影响截然相反。为实现对古建筑的预防性保护,需要量化古建筑纯木结构中的残损状态及修缮措施对其安全状态的影响。基于山西万荣飞云楼各构件残损状态普查统计数据,结合现有规范及工程经验对构件残损状态等级详细划分,建立4级模糊层次分析模型,确定结构体中承重构件及构件残损类型的权重值及判断矩阵,通过模糊层次分析方法对飞云楼进行安全状态评估。结果表明,建立的模糊层次安全评价模型能反映残损状态及修缮措施对飞云楼安全状态的影响,有效将结构评价与构件评价联系起来,验证了修缮措施能有效增强古建筑结构本体的安全性及稳定性,该模型及方法可以应用到多层古建木结构的安全等级评价中。

Review the Environmental Effects of Using Industrial Wastewater Effluent (Case Study: Iran Qom Shokouhie Industrial State)

The overall goal of this study is investigating the environmental impacts of using wastewater effluent of industrial states in irrigation of green space. For this purpose, industrial state of Shokouhieh in Qom Province in central of Iran was selected as a case study. Firstly, the quality and quantity of inputting wastewater into refinery and outputting wastewater effluent were measured on important parameters of pH, TDS, TSS, COD, BOD and wastewater temperature in refinery laboratory of industrial state of Qom Shokouhieh during 12 months from March 2012 to March 2013. Then analysis of chemical, biological and physical indicators of irrigation wastewater (effluent) and measurement of heavy metals were done in June 2012 and January 2013 according to the standards instruction for the water and wastewater treatment. Also, heavy metals, EC, pH, and Mg2+, Ca2+, Na+, k+ of soil of industrial estate of Qom Shokouhieh were studied. Then, Rapid Impact Assessment Method (RIAM) and Entropy Method were used to analyze the data. In Rapid Impact Assessment Method, socio-cultural, physicochemical, biological and economic environments get the highest negative impacts respectively. In Entropy Method after weighting the environmental factors, public health and other disease parameters with the weight of 0.147, soil chemical properties with the weight of 0.136, soil toxicity with the weight of 0.126 were allocated the first rate up to the third rate respectively. After comparing the results of these two methods with each other, the main limitation of using wastewater effluent of industrial estate of Qom Shokouhie in irrigation of green space is entering chemical pollutants (nitrate) into groundwater, salinity and toxicity of soil of industrial state and endangerment of workers and labors public health who work in industrial state of Qom Shokouhie (specially the labors who exposure directly with the wastewater effluent and labors work in refinery).