Cumulative Deterioration Research Articles

Implementing well-being in the management of psoriasis: An expert recommendation.

Psoriasis causes detriment in a person's physical, mental and social health which impairs their quality of life (QoL). However, the current psoriasis management may not adequately address all relevant health domains. Since the goal of healthcare is to restore or maintain health, health outcomes should include all areas of the patient's overall health. Life satisfaction, QoL and patient well-being are essential to a comprehensive approach to the disease. With the inclusion of more people-centred policies, care of patients with psoriasis should evolve towards a holistic and integrated assessment of the disease impact, including subjective measures of well-being in order to encompass all aspects of health. The main objective of this expert review is to give the concept of well-being a place as an entity within the holistic therapeutic approach for patients with psoriasis. Identifying and defining common goals beyond the skin with the patient and testing them throughout the course of treatment will benefit and enhance treatment success. We propose a series of recommendations for application in clinical practice, providing tangible clinical guidance for implementing well-being in the management of psoriasis. Among the recommendations are the need to initially listen to the patient, to know their level of empowerment or what they want to achieve, their preferences in decision making, the evaluation of not only the physical but also the emotional impact of the disease (well-being), the definition of the aspects that can generate a cumulative deterioration of the disease throughout life, and a continuous assessment of the patient's preferences with the opinion of the expert clinician and the integration of the knowledge of external clinical evidence.

Spatio-temporal dynamics and sensitive distance of nighttime light environment in Pearl River Delta Protected Areas, China.

Protected areas (PAs) are important barriers to ensure the ecological security of territory. Light pollution is a threat to PAs, which is particularly obvious in the urban agglomeration environment. We used multi-source big data (satellite remote sensing light data, land cover types and points of interest) to quantitatively analyze the temporal and spatial dynamics of nighttime light in the PAs of the Pearl River Delta (PRD) urban agglomeration from 2000 to 2018, the correlation between the night light environment within the PAs and human activity intensity outside, as well as the sensitive distance of the PAs to artificial light interference. The results showed that the total value of nighttime light data of PAs in the PRD increased from 71107 nanoW·cm-2·sr-1 to 127682 nanoW·cm-2·sr-1 from 2000 to 2018, the mean value per pixel increased from 15.3 nanoW·cm-2·sr-1 to 23.7 nanoW·cm-2·sr-1, and the lighted ratio increased from 73.3% to 86.4%, indicating that the nighttime light environment of PAs in the region were facing cumulative deterioration risks and serious challenges. The nighttime light intensity of the PAs in the core area of the PRD was much higher than that in the peripheral areas such as Zhaoqing and Huizhou, whereas the expansion degree of the PAs in the peripheral areas was higher than that in the core area. The nighttime light environment inside the PAs was positively correlated with the intensity of human activities around it. The most sensitive distance of the PAs to the artificial light interference around it was 10 km, and the interference degree tended to be stable after 30 km. We proposed that 0-10 km area outside the boundary of the PAs should be the light control core zone and 10-20 km area as the control buffer zone.

USING MACHINE LEARNING METHODS TO PREDICT HYDRAULIC PUMP REMAINING USEFUL LIFE

This article discusses a sampling algorithm for machine learning in order to capture the trend of the cumulative deterioration of the characteristics of a hydraulic pump (cumulative degradation), which affects the efficiency of its operation and manifests itself in the form of a drop in volumetric efficiency. To generate data, a simulation model of a typical station for the supply of working fluid in technological complexes, developed in the SimulationX program, is used. The transient processes of pressure change in the system are described, from the analysis of which a tendency of a decrease in the average component of the pressure signal is traced, which is used as a diagnostic feature - an indicator of the state of the system. An example is also considered that describes the possibility of assessing the residual life of the system based on data characterizing the past state of the system, and can be adapted when forming a more complex base, taking into account the use of artificial neural networks.

The number of catalytic cycles in an enzyme’s lifetime and why it matters to metabolic engineering

Metabolic engineering uses enzymes as parts to build biosystems for specified tasks. Although a part's working life and failure modes are key engineering performance indicators, this is not yet so in metabolic engineering because it is not known how long enzymes remain functional in vivo or whether cumulative deterioration (wear-out), sudden random failure, or other causes drive replacement. Consequently, enzymes cannot be engineered to extend life and cut the high energy costs of replacement. Guided by catalyst engineering, we adopted catalytic cycles until replacement (CCR) as a metric for enzyme functional life span in vivo. CCR is the number of catalytic cycles that an enzyme mediates in vivo before failure or replacement, i.e., metabolic flux rate/protein turnover rate. We used estimated fluxes and measured protein turnover rates to calculate CCRs for ∼100-200 enzymes each from Lactococcus lactis, yeast, and Arabidopsis CCRs in these organisms had similar ranges (<103 to >107) but different median values (3-4 × 104 in L. lactis and yeast versus 4 × 105 in Arabidopsis). In all organisms, enzymes whose substrates, products, or mechanisms can attack reactive amino acid residues had significantly lower median CCR values than other enzymes. Taken with literature on mechanism-based inactivation, the latter finding supports the proposal that 1) random active-site damage by reaction chemistry is an important cause of enzyme failure, and 2) reactive noncatalytic residues in the active-site region are likely contributors to damage susceptibility. Enzyme engineering to raise CCRs and lower replacement costs may thus be both beneficial and feasible.

Stochastic comparisons and ageing properties of an extended gamma process

AbstractExtended gamma processes have been seen as a flexible extension of standard gamma processes in the recent reliability literature, for the purpose of cumulative deterioration modeling. The probabilistic properties of the standard gamma process have been well explored since the 1970s, whereas those of its extension remain largely unexplored. In particular, stochastic comparisons between degradation levels modeled by standard gamma processes and ageing properties for the corresponding level-crossing times are now well understood. The aim of this paper is to explore similar properties for extended gamma processes and see which ones can be broadened to this new context. As a by-product, new stochastic comparisons for convolutions of gamma random variables are also obtained.

Напрямки економіко-екологічної трансформації підприємств оборонно-промислового комплексу України

Since the beginning of the third millennium, ecological safety has become of paramount importance for Ukraine. The cumulative deterioration of the environment, fixed by the annual official reports on the ecological situation in the country, is fraught with irreparable consequences not only for the present generations, but also for descendants. The authors propose to consider the enterprises of the defence-industrial complex (DIC) of Ukraine as those that make a significant contribution to the development of the economy of the country, while not only not destroying the environment, but also contributing to sustainable development. The defence-industrial complex of Ukraine is the basis of the high-tech sector of the Ukrainian economy, which determines its key importance for the functioning and development of the entire national economy, in the current period of change of technological modes, as the enterprises of the Ukrainian defence-industrial complex have a high level of innovation. One of the key features of the domestic defence-industrial complex is that it has the potential to concentrate various types of resources to achieve breakthrough results not only in addressing the issues of creating the latest weapons and military equipment, but also for implementing large-scale projects of national economic importance. This potential for breakthrough development currently remains underutilized, requiring adjustments not only in industrial, but also in state economic policy as a whole. The current state of development of defence industry enterprises is characterized by insufficient economic and environmental sustainability and requires modernization based on global experience in the greening of the military-defence sphere and NATO environmental standards, which will have environmental and economic effects. The obstacles of economic and ecological transformation of enterprises of the defence-industrial complex of Ukraine were identified and a number of managerial decisions that can become drivers to accelerate the economic and ecological transformation of the defence-industrial complex of Ukraine were proposed.

Cumulative surgical morbidity in patients with multiple cerebellar and medullary hemangioblastomas

ObjectivePatients affected with von Hippel-Lindau disease often develop multiple hemangioblastomas in the cerebellum and spinal cord. Timing of surgical intervention is difficult and depends largely on the anticipated surgical morbidity. However, data regarding surgical outcome after multiple cerebellar and medullary surgeries are scarce. Our objective was to evaluate cumulative surgical morbidity in patients operated on multiple cerebellar and medullary hemangioblastomas and to deduce recommendations for treatment. MethodsWe performed a retrospective analysis for a consecutive cohort of von Hippel-Lindau patients with surgical treatment of at least two cerebellar and/or medullary hemangioblastomas. Pre- and postoperative functional grades were reviewed in patients' files and compared by Modified Ranking Scale (cerebellar surgeries) or by Modified McCormick Score (medullary surgeries). ResultsThirty-six patients were surgically treated for at least two cerebellar hemangioblastomas (12 patients), at least two medullary hemangioblastomas (19 patients) or at least two hemangioblastomas in both locations (5 patients). Fourthy-eight cerebellar and 80 medullary procedures were performed in total. On average, multiple cerebellar surgeries caused no clinical deterioration, whereas multiple medullary surgeries led to a slight cumulative deterioration of postoperative functional grades. The severity of this deterioration did not correlate to the number of performed medullary surgeries. ConclusionResection of multiple cerebellar hemangioblastomas is not associated with cumulative morbidity. Although there is a certain cumulative surgical morbidity caused by medullary surgeries, its extent does not increase with the number of performed surgeries. Microsurgical removal of asymptomatic tumors with radiographic progression can also be considered for patients with multiple tumors and previous surgeries.

Model parameter estimation and residual life span prediction of pneumatic diaphragm pump based on hidden Markov model in intelligent spraying

Pneumatic diaphragm pump is an important part in intelligent spraying. When pneumatic diaphragm pump does not work normally, the entire intelligent spraying product line will be malfunctioned. To maintain and manage pneumatic diaphragm pump effectively, the grade analysis of the health status of pneumatic diaphragm pump is generally used according to its working state. Due to the effects of condition monitoring and random faults, some observable health predictions are often inaccurate. There are very few papers dealing with the health monitoring of pneumatic diaphragm pump and their estimation of residual life span. In this article, a method with vector autoregressive model and continuous-time hidden Markov model was proposed to analyze and evaluate the life span of pneumatic diaphragm pump based on the estimation error of the health condition and the cumulative deterioration of pneumatic diaphragm pump. It is modeled through a continuous-time Markov chain with three states, which includes unobservable healthy state 0, unobservable warning state 1, and observable fault state 2. The expectation–maximization algorithm is used to estimate the model parameters of the fitted hidden Markov. Through the posterior probability of pneumatic diaphragm pump in warning state 1, the derived conditional reliability function and mean residual life span formula can be calculated to evaluate the residual life span of pneumatic diaphragm pump. The results showed that the method can effectively predict the residual life span of pneumatic diaphragm pump, illustrate the effectiveness of the model, and improve the accuracy of the health status rating.

Parallel-machine scheduling with job-dependent cumulative deterioration effect and rejection

We study a parallel-machine scheduling problem in which job rejection is allowed and the actual processing time of a job depends on the sum of certain parameters associated with the jobs scheduled earlier. The goal is to minimize the sum of the makespan of the accepted jobs and total rejection penalty of the rejected jobs. When the number of machines is fixed, we develop an exact dynamic programming algorithm and a fully polynomial-time approximation scheme for solving it. When the number of machines is restricted to one, we reformulate the problem as a variant of a half-product problem, which allows us to design a fully polynomial-time approximation scheme with the best possible running time.

Two-agent single-machine scheduling with cumulative deterioration

We address cumulative deterioration scheduling in which two agents compete to perform their respective jobs on a single machine. By cumulative deterioration we mean that the actual processing time of any job of the two agents is a linear increasing function of the total normal processing times of already processed jobs. Each agent desires to optimize some scheduling criterion that depends on the completion times of its own jobs only. We study several scheduling problems arising from different combinations of some regular scheduling criteria, including the maximum cost (embracing lateness and makespan as its special cases), the total completion time, and the (weighted) number of tardy jobs. The aim is to find an optimal schedule that minimizes the objective value of one agent while maintaining the objective value of the other agent not exceeding a fixed upper bound. For each problem under study, we design either a polynomial-time or a pseudo-polynomial-time algorithm to solve it.

Experiment and Study on Mechanical Property of Sandstone Post-peak Under the Cyclic Loading and Unloading

Engineering research has shown that the surrounding rock of deep roadways experienced many times of post-peak cyclic loading and unloading. So studying on rock mechanical characteristics of post-peak loading and unloading is helpful to control the deep surrounding rocks. The test using RMT-150B rock mechanics testing system, to experiment on the mechanical properties of sandstone of post-peak cyclic loading and unloading. The results show that: the stress–strain curves of post-peak cyclic loading and unloading have significant plastic hysteretic loops. The area of plastic hysteretic loops gloss back. The enveloping outer enclosure of cycle loading curve is the similar as the stress–strain curves of strain softening stage when the samples failure, which shows that post-peak failure of rocks have significant memory. With the increase of cycles, the cumulative deterioration parameters are gradually increased, and the ultimate bearing capacity, elastic of loading section of samples and cumulative deterioration parameters conform with the exponential attenuation function with constant term. With the increase of surrounding pressure, the total energy, dissipated energy and elastic energy of samples are gradually increased. With the increase of cycles, the total energy, dissipated energy and elastic energy of samples all are gradually decreasing, the rate of reduction decreases gradually. The samples exist in vertical splitting and transverse shear combination failure under the post-peak uniaxial cycles, or exist in shear failure under the post-peak triaxial cycles. The shear plane exists slip traces.

Generalized method of moments for an extended gamma process

ABSTRACTIn reliability theory, a widely used process to model the phenomena of the cumulative deterioration of a system over time is the standard gamma process (SGP). Based on several restrictions, such as a constant variance-to-mean ratio, this process is not always a suitable choice to describe the deterioration. A way to overcome these restrictions is to use an extended version of the gamma process introduced by Cinlar (1980), which is characterized by shape and scale functions. In this article, the aim is to propose statistical methods to estimate the unknown parameters of parametric forms of the shape and scale functions. We here develop two generalized methods of moments (Hansen 1982), based either on the moments or on the Laplace transform of an extended gamma process. Asymptotic properties are provided and a Wald-type test is derived, which allows to test SGPs against extended ones with a specific parametric shape function. Also, the performance of the proposed estimation methods is illustrated on simulated and real data.

Common due date assignment and cumulative deterioration scheduling on a single machine

ABSTRACTThis article addresses a single-machine scheduling and common due date assignment problem in which the actual processing time of a job is a linear increasing function of the total basic processing times of already processed jobs. The aim is to determine simultaneously the common due date and job schedule that will minimize a cost penalty function including the due date assignment cost, total earliness penalties and a weighted number of tardy jobs. The problem is shown to be -hard even if there is no earliness penalty. Moreover, a pseudo-polynomial time algorithm and a fully polynomial time approximation scheme are proposed to solve the problem. An time algorithm is designed to solve the special case when all jobs have identical tardiness penalties.

Approximate Simulation Techniques and Distribution of an Extended Gamma Process

In reliability theory, many papers use a standard Gamma process to model the evolution of the cumulative deterioration of a system over time. When the variance-to-mean ratio of the system deterioration level varies over time, the standard Gamma process is not convenient any more because it provides a constant ratio. A way to overcome this restriction is to consider the extended version of a Gamma process proposed by Cinlar (J Appl Probab 17:467–480, 1980). However, based on its technicality, the use of such a process for applicative purpose requires the preliminary development of technical tools for simulating its paths and for the numerical assessment of its distribution. This paper is devoted to these two points.

Defect creation in InGaAs/GaAs multiple quantum wells–I. Structural properties

We present a systematic study of extended defect creation in InGaAs/GaAs multiple quantum well (MQW) structures. Three sets of samples, grown by molecular beam epitaxy, were characterized by high-resolution x-ray diffraction and transmission electron microscopy. First, in a temperature series, optimal deposition temperature of 505°C was found for the In composition of 20% as determined from dislocation loop (DL) density and inspection of diffuse scattering patterns. InGaAs decomposition and lateral layer thickness undulations were observed above this optimal temperature. Second, increase of MQW periodicity from ×5 to ×10 revealed a thickness-related cumulative deterioration, characterized by increased likelihood of defect intersection with continued MQW growth, as suggested by an increase of the secondary DL density from ~1.6×107cm−2 to ~6×108cm−2. Additional strained layers experienced an ever-degrading quality of the growth surface. Third, a set consisting of samples with three different MQW periods was investigated. Different stages, suggested by a model of defect creation, were obtained for these different MQW periods, allowing specification of particular type, density, and spatial distribution of extended defects for each stage of defect creation.

Defect Creation in InGaAs/GaAs Multiple Quantum Wells – II. Optical Properties

The optical properties of three sets of InGaAs/GaAs multiple quantum well (MQW) structures grown by molecular beam epitaxy and previously characterized by x-ray diffraction for crystal perfection were investigated. The correlations between growth conditions, crystal defects, and optical properties are discussed. Evaluation of the relative importance of non-radiative Shockley-Read-Hall (SRH) recombination was carried out according to a method presented herein. The optimal deposition temperature was determined based on both proper carrier confinement in the nanostructures and the least non-radiative recombination. Growing below this temperature increased SRH-recombination whereas higher growth temperatures led to carrier localization in local band edge minima. Varying the MQW periodicity and MQW period allowed the study of their effects on the strength of SRH-recombination. MQW periodicity results are explained in the frame of a cumulative deterioration effect with continued epitaxial growth, while MQW period data shows correlations between relaxation of the initial elastic stress and SRH-strength. Limitations of the underlying model for SRH-analysis are pointed out.

N Subpopulations experiencing stochastic degradation: reliability modeling, burn-in, and preventive replacement optimization

For some engineering design and manufacturing applications, particularly for evolving and new technologies, populations of manufactured components can be heterogeneous and consist of several subpopulations. The co-existence of n subpopulations is particularly common in devices when the manufacturing process is still maturing or highly variable. A new model is developed and demonstrated to simultaneously determine burn-in and age-based preventive replacement policies for populations composed of distinct subpopulations subject to stochastic degradation. Unlike traditional burn-in procedures that stress devices to failure, we present a decision rule that uses burn-in threshold on cumulative deterioration, in addition to burn-in time, to eliminate weak subpopulations. Only devices with post-burn-in deterioration levels below the burn-in threshold are released for field operations. Inspection errors are considered when screening burned-in devices. Preventive replacement is employed to prevent failures from occurring during field operation. We examine the effectiveness of such integrated polycies for non-homogeneous populations. Numerical examples are provided to illustrate the proposed procedure. Sensitivity analysis is performed to analyze the impacts of model parameters on optimal policies. Numerical results indicate there are potential cost savings from simutaneouly determining burn-in and maintenance policies as opposed to a traditional approach that makes decisions on burn-in and maintenance actions separately.

AGING IS A PROCESS…….. NOT A DISEASE

The advance of age is an extremely complicated procedure utilizing every cell and part of our mechanism of physiology that we have. As we grow older things begin to go wrong with us. Our vascular system, digestive tract and respiratory system begin to show their age. But why does aging occur? This article is dealing with the aging process of the skin only. Since skin show the changes that draws the attention of the person and others. The skin is an organ with its surface area measuring about 1.52 square meters (16 to 22 square feet); it is not merely a protective barrier. It serves to regulate excretion of metabolic waste products, regulates temperature, and has receptors for pain, tactile sensation, and pressure. The health and appearance of the skin, reflects the lifestyle, dietary habits and the age of the individual. Aging process is associated with a loss of fibrous tissue, slower rate of cellular renewal, and a reduced vascular and glandular network. The barrier that maintains cellular hydration also becomes impaired. The subcutaneous tissue (hypodermis) flattens, particularly in the face, hands and feet. Aging of the skin is influenced by many factors as ultraviolet radiation, excess alcohol consumption, tobacco abuse, and environmental pollution. Increase in body weight and rise in blood sugar levels, disrupt the biochemical reactions and the very structural framework of the skin. All these factors lead to cumulative deterioration in skin appearance and function.

Approximation schemes for scheduling on a single machine subject to cumulative deterioration and maintenance

We consider a scheduling problem on a single machine to minimize the makespan. The processing conditions are subject to cumulative deterioration, but can be restored by a single maintenance. We link the problem to the Subset-sum problem (if the duration of maintenance is constant) and to the Half-Product Problem (if the duration of maintenance depends on its start time). For both versions of the problem, we adapt the existing fully polynomial-time approximation schemes to our problems by handling the additive constants.

Single machine scheduling with precedence constraints and positionally dependent processing times

In many real-life situations the processing conditions in scheduling models cannot be viewed as given constants since they vary over time thereby affecting actual durations of jobs. We consider single machine scheduling problems of minimizing the makespan in which the processing time of a job depends on its position (with either cumulative deterioration or exponential learning). It is often found in practice that some products are manufactured in a certain order implied, for example, by technological, marketing or assembly requirements. This can be modeled by imposing precedence constraints on the set of jobs. We consider scheduling models with positional deterioration or learning under precedence constraints that are built up iteratively from the prime partially ordered sets of a bounded width (this class of precedence constraints includes, in particular, series–parallel precedence constraints). We show that objective functions of the considered problems satisfy the job module property and possess the recursion property. As a result, the problems under consideration are solvable in polynomial time.