Modern Development and Maintaining Self-Developing Identity

Two recent trips to cities in China got me thinking a lot about China’s development and efforts to maintain its identity.While China is developing with strong momentum in every sector,it has succeeded at preserving and upholding its ancient traditions and customs.These trips showed me a country not only keen on technological and infrastructural advancement but also deeply committed to cultural preservation and promotion.In every corner of these cities,I witnessed a harmonious blend of the old and new,a testament to China’s dedication to maintaining its cultural heritage while embracing modernity.

Optimizing reliability, maintainability and testability parameters of equipment based on GSPN

Reliability, maintainability and testability （RMT） are important properties of equipment, since they have important influ- ence on operational availability and life cycle costs （LCC）. There- fore, weighting and optimizing the three properties are of great significance. A new approach for optimization of RMT parameters is proposed. First of all, the model for the equipment operation pro- cess is established based on the generalized stochastic Petri nets （GSPN） theory. Then, by solving the GSPN model, the quantitative relationship between operational availability and RMT parameters is obtained. Afterwards, taking history data of similar equipment and operation process into consideration, a cost model of design, manufacture and maintenance is developed. Based on operational availability, the cost model and parameters ranges, an optimization model of RMT parameters is built. Finally, the effectiveness and practicability of this approach are validated through an example.

Predicting the Maintainability of Open Source Software Using Design Metrics

This paper empirically investigates the relationships between 15 design metrics and maintainability of 148 Java open source software. The results show that size and complexity metrics are strongly related to the maintainability of open source software. However, cohesion and coupling, as currently captured by existing metrics, do not seem to have a significant impact on maintainability. When used together, these metrics can predict system maintainability fairly accurately （mean MREs below 30%）.

Electric Multiple Unit Bogie Maintainability Allocation with Interval Analysis and Fuzzy Evaluation Method

Based on the failure rate and design features allocation method,considering the multiple influential factors which affect electric multiple unit( EMU) bogies,maintainability allocation on EMU bogie was presented by interval analytic hierarchy analysis and fuzzy comprehensive assessment. The maintainability allocation model was established. Weight based on the influence degree of each factor on maintenance was assigned. Fuzzy interval numbers were used to substitute real numbers and express uncertain information.The maintenance weighting factors for each subsystem were calculated by fuzzy comprehensive assessment. Then the allocation method was applied to EMU bogie. The results show that the method is feasible. The problem difficult to quantify for EMU bogie maintenance allocation is solved effectively.

Maintainability Analysis Visualization System and Its Development in AutoCAD Environment

Maintainability is an important design characterist ic , and also is a design parameter. The essence of maintainability design is to ex pect and solve possible maintenance problems at early stage during product devel opment, maintainability must be designed into product simultaneously. But curren t maintainability methods do not support concurrent engineering. This paper anal yzes the deficiencies of existing maintainability technologies, and introduces t he concept of maintainability analysis visualization. The two major deficiencies are that maintainability analysis time lags behind product design, and the main tainability techniques do not accommodate modern product design concepts. After this, the infrastructure of maintainability analysis visualization system is dis cussed. The system are composed of four subsystems, they are product modeling, d isassembly process modeling, simulation and analysis, and user interface. Produc t modeling is accomplished with the capability of CAD system, disassembly proces s modeling is mainly a reason process based on assembly information. The system is integrated into AutoCAD so that designer can timely analyze their product des ign from the viewpoint of easy maintenance. Human model generation function, hum an task analysis function, tool analysis function, visibility analysis function is implemented, disassembly process planning function is still under developing.

Layout problem of multi-component systems arising for improving maintainability

To improve the maintainability design efficiency and quality,a layout optimization method for maintainability of multi-component systems was proposed.The impact of the component layout design on system maintainability was analyzed,and the layout problem for maintainability was presented.It was formulated as an optimization problem,where maintainability,layout space and distance requirement were formulated as objective functions.A multi-objective particle swarm optimization algorithm,in which the constrained-domination relationship and the update strategy of the global best were simply modified,was then used to obtain Pareto optimal solutions for the maintainability layout design problem.Finally,application in oxygen generation system of a spacecraft was studied in detail to illustrate the effectiveness and usefulness of the proposed method.The results show that the concurrent maintainability design can be carried out during the layout design process by solving the layout optimization problem for maintainability.

Softw are Maintainability Evaluation Based on Software Configuration Management Data

As one of the most important attributes of software quality, software maintainability has been widely recognized.However,the existing maintainability evaluation methods are mostly based on subjectively judgment. Thus it is inapplicable or unbelievable. To evaluate software maintainability objectively,the software configuration management( SCM) data are collected to establish a maintainability model. Based on the hidden Markov chain( HMC), a three-state maintainability estimation model is constructed. To validate the feasibility of the model,a real software example of software maintenance activity is given and the result from the example shows the effectiveness of the proposed method.

Clustering-based maintainability demonstration for complex systems with a mixed maintenance time distribution

During maintainability demonstration,the maintenance time for complex systems consisting of mixed technologies generally conforms to a mixture distribution.However existing maintainability standards and guidance do not explain explicitly how to deal with this situation.This paper develops a comprehensive maintainability demonstration method for complex systems with a mixed maintenance time distribution.First of all,a K-means algorithm and an expectation-maximization(EM)algorithm are used to partition the maintenance time data for all possible clusters.The Bayesian information criterion(BIC)is then used to choose the optimal model.After this,the clustering results for equipment are obtained according to their degree of membership.The degree of similarity for the maintainability of different kinds of equipment is then determined using the projection method.By using a Bootstrap method,the prior distribution is obtained from the maintenance time data for the most similar equipment.Then,a test method based on Bayesian theory is outlined for the maintainability demonstration.Finally,the viability of the proposed approach is illustrated by means of an example.

Softw are Maintainability Evaluation Based on Quantitive Model

Software maintainability is one of the most important factors of software quality,but it is seriously difficult to evaluate the maintainability. Without evaluation,it is impossible to control. To estimate software maintainability state,parameter system of software was built up and maintainability state was defined into three states.Thought of application on maintainability evaluation based on hidden Markov chain( HMC) and fuzzy inference was presented.Three-state maintainability estimation model was constructed. To testify the feasibility of the model, a real example of software maintenance activity was carried out and the result from the example validated that the results of this study were applicable.

Product Maintainability Design Method and Support Tool Based on Feature Model

Maintainability is an important character which is given by product design process. The maintainability design criteria and measure index used in product maintainability analysis are summarized and discussed in this paper. A product maintainability design method is studied by integrating the product feature model, maintainability design criteria with measure index. Product feature model can be built on the basis of the product feature library quickly. Product feature library for steam turbine design is created by using SolidWorks design library origination structure. A methodology which supports the design and development of product maintainability design support tool (PMDSTs) is put forward. The function of PMDSTs is designed by using UML (Unified Modeling Language) use case diagram, it is developed by using VC++ 6.0. The maintainability analysis application case of steam turbine-generator system is given at last.

Softw are Maintainability Prediction with UML Class Diagram

Software system can be classified into many function modules from the perspective of user. Unified modeling language( UML) class diagram of each function module was extracted,and design characteristic metrics which influenced software maintainability were selected based on UML class diagram.Choosing metrics of UML class diagram as predictors,and mean maintenance time of function module was regarded as software maintainability parameter. Software maintainability models were built by using back propagation( BP) neural network and radial basis function( RBF) neural network, respectively and were simulated by MATLAB. In order to evaluate the performance of models,the training results were analyzed and compared with leaveone-out cross-validation and model performance evaluation criterion. The result indicated that RBF arithmetic was superior to BP arithmetic in predicting software maintainability.

Intellectualization of Design Technique for Product Maintainability

The basis of the two guideline lectures for maintainability design, namely''maintainability design criterions'' and ''cases compilation of maintainability design technique'' , anintellectualized architecture for combining rule-based reasoning (RBR) and case-based reasoning(CBR), is presented in this paper by analyzing from maintainability design procedure to the thoughtof our solving the maintainability design problem. Furthermore, the domain model and reasoningprocess is introduced and a representation of maintainability domain knowledge is given. Finally,the computer-aided engineering system for maintainability design (MCAES) which is based onintellectualized architecture is reported; its function and implementation is described.

Knowledge Engineering Application in maintainability Design and Analysis

With the development of automatic design and artificial intelligence techniques, intelligence already have been applied in maintainability design and analysis of military /commercial equipment. Expert system has been used in diagnosis, design analysis, testability design, etc. In this paper, we will discuss about knowledge engineering application in two types. One is integrated knowledge base system for maintainability, it's the baseline of concurrent, intelligence design and it's also suitable for the present situation in China that there is lack of maintainability engineers. The other application is expert system for formulating maintainability design criteria and it can take full advantage of experts' experiences and past cases. Under development trend of intelligence design, these two systems will have good effects on maintainability design and analysis.

Maximum Likelihood Method of Maintainability Growth Evaluation for Weapon Equipment

The evaluation of maintainability growth plays an important role in improving materiel system effectiveness. Based on field maintenance information, a maximum likelihood model is put forward to evaluate the maintainability growth at the system level and sub-system level. A maximum likelihood function can be built after all the maintenance data can be divided into the following three categories： incomplete repair time data, complete repair time data, super-complete repair time data. According to the actual situation of the maintenance data, an appro- priate approximation can be made and the approximate analytical solution can be obtained. The values of u and can be obtained as the corresponding estimated value of unknown parameters. By effectively mining the latent sampie information, the maintainability growth evaluation is logical and reasonable.

An Improved Functional Hierarchy Frame Model for System Maintainability

By means of analogy, this paper analyses the present functional hierarchyframe model for system maintainability, and presents an improved model. Practical applicationindicates that the improved model is visualized, more convenient and perfected over the perviousmodels.

Lipolysis supports bone formation by providing osteoblasts with endogenous fatty acid substrates to maintain bioenergetic status

Bone formation is a highly energy-demanding process that can be impacted by metabolic disorders.Glucose has been considered the principal substrate for osteoblasts,although fatty acids are also important for osteoblast function.Here,we report that osteoblasts can derive energy from endogenous fatty acids stored in lipid droplets via lipolysis and that this process is critical for bone formation.As such,we demonstrate that osteoblasts accumulate lipid droplets that are highly dynamic and provide the molecular mechanism by which they serve as a fuel source for energy generation during osteoblast maturation.Inhibiting cytoplasmic lipolysis leads to both an increase in lipid droplet size in osteoblasts and an impairment in osteoblast function.The fatty acids released by lipolysis from these lipid droplets become critical for cellular energy production as cellular energetics shifts towards oxidative phosphorylation during nutrient-depleted conditions.In vivo,conditional deletion of the ATGL-encoding gene Pnpla2 in osteoblast progenitor cells reduces cortical and trabecular bone parameters and alters skeletal lipid metabolism.Collectively,our data demonstrate that osteoblasts store fatty acids in the form of lipid droplets,which are released via lipolysis to support cellular bioenergetic status when nutrients are limited.Perturbations in this process result in impairment of bone formation,specifically reducing ATP production and overall osteoblast function.

A Maintainability Prediction Method Considering Environmental Impacts and Cost

Maintainability prediction is one kind of primary maintainability action. Design deficiency would be found through predicting maintainability parameters under certain conditions. Now a maintainability prediction method that mainly considers maintenance time or maintenance man hour is a kind of prediction method with a single index. With increasing product complexity and people's environmental consciousness, more attention is paid to environment impacts and maintenance cost or resource consumption in the maintenance process. It is necessary for a maintainability prediction method that can predict maintenance cost and maintenance environmental impacts. A new maintainability prediction method is presented in this paper based on analyzing existing maintainability prediction methods. The method is MABTCE(maintenance activity based timing/costing/environment impact assessment) and can predict maintenance time, maintenance costing and maintenance environmental impacts and then improve maintainability design with prediction results.

StSN2 interacts with the brassinosteroid signaling suppressor StBIN2 to maintain tuber dormancy

After harvest,potato tubers undergo an important period of dormancy,which significantly impacts potato quality and seed vigor.StSN2 has been reported as a key gene for maintaining tuber dormancy;in this study,we explored the molecular mechanism by which StSN2 maintains dormancy.StBIN2 was first identified as a candidate protein that interacts with StSN2 by co-immunoprecipitation/mass spectrometry,and both qPCR and enzyme activity experiments showed that StSN2 can promote the StBIN2 expression and activity.In addition,the interaction between StSN2 and StBIN2 was verified by yeast two-hybrid,luciferase complementation experiments and co-immunoprecipitation.Bioinformatics analysis and site-directed mutagenesis confirmed the critical role of cysteine residues of StBIN2 in its binding to StSN2.Similar to that of StSN2,overexpression of StBIN2 extended the dormancy of potato tuber.Interaction between StSN2 and StBIN2 increased the activity of the StBIN2 enzyme,inhibited the expression of StBZR1,and suppressed BR signaling.On the contrary,this interaction promoted the expression of StSnRK2.2/2.3/2.4/2.6 and StABI5,key genes of ABA signaling,and the phosphorylation of StSnRK2.3,thereby promoting ABA signaling.Altogether,our results indicate that StSN2 interacts with StBIN2 through key cysteine residues and StBIN2 maintains tuber dormancy by affecting ABA and BR signaling.Findings of this research offer new insights into the molecular mechanism by which StSN2 maintains potato tuber dormancy through interaction with StSIN2 and provide guidance for potato improvement.

Shear Bond Strength of Different Types of Cement Used for Bonding Band and Loop Space Maintainer

Purpose: The present study aimed to evaluate the effects of thermal aging on the shear bond strength of three different types of cement used to retain band and loop space maintainers cemented on extracted human permanent molar teeth. Methods: A total of 66 newly extracted permanent molars were used in this study. Eighteen teeth were used as a control and did not undergo thermal aging (six per group). All sample teeth were randomly divided into three groups: KetacCem, RelyX Luting Plus, and RelyX Unicem 2. After bonding procedures, all experimental groups undergo thermal aging. The shear bond strength of all samples was conducted using the Ultratester machine. Findings were statistically analyzed using the ANOVA and Turkey’s post hoc tests. Results: Among the examined groups, Ketac Cem presented with the highest recorded shear bond (11.4 MPa), while RelyX Luting Plus showed the lowest (3.2 MPa). The control groups recorded the highest shear bond strength compared to all examined groups;Ketac Cem showed the highest shear bond strength (12.8 Mpa), and RelyX Luting Plus had the least recorded reading (5.4 Mpa). Conclusion: Within the limitation of the present study, there was a statistically significant difference between the examined groups;Ketac Cem showed a higher shear bond cement than RelyX luting Plus and RelyX Unicem.

New Study Uncovers How Immune Tolerance to Food Is Maintained

Eating a meal normally doesn’t trigger an inflammatory immune reaction,but how the body maintains tolerance to food has been unclear.Now,a new study published in Cell(doi:10.1016/j.cell.2023.05.027)by scientists at the University of Science and Technology of China(USTC)and Yale University School of Medicine reveals an unexpected role of a protein called gasdermin D(GSDMD)in inducing immune tolerance to food in the small intestine.