Recent Patents on Engineering - Volume 15, Issue 1, 2021

Background: Through smart micro sensor devices networked via wireless links and the Internet, wireless sensor networks offer unprecedented opportunities for diverse applications, such as healthcare, military, industry automation, and monitoring, environmental sensing, etc. It is one of the enabling technologies for many Internet of Things and cyber-physical systems. Due to the mission-critical nature of these systems, it is imperative that a wireless sensor network operates correctly throughout the intended mission time. Thus, modeling the reliability of wireless sensor networks is a critical task for their successful operations. Objective: This article is aimed to review the state-of-the-art work on the reliability modeling and analysis of wireless sensor networks. Methods: The existing reliability modeling works for wireless sensor networks are identified and classified based on different aspects, including scope, topology, communication paradigms, designs, and reliability evaluation methods. Patents contributing to the reliability of wireless sensor networks are also discussed. Conclusion: A rich body of works have been suggested for the reliability modeling and analysis of wireless sensor networks contributing to their robust design and resilient operation. However, there is still a great need to explore more efficient and innovative solutions to capture new aspects of system complexity related to the development and growth of wireless sensor networks in contemporary and future critical applications.

Background: Multi-stress accelerated life test (MALT) has obtained increasing attention in reliability assessment due to its advantages. Started with constant-stress ALT with two stress variables, MALT has developed a lot during the past decades. In MALT, the design of the test plan and data analysis are two crucial aspects. Numerous researchers have discussed these two aspects and some important methods of planning and data analysis for MALT are presented. Methods: We first conducted a survey in the journal databases including Elsevier, Springer, IEEEXplore, Wiley and Taylor & Francis; and patent databases like Spacenet, USPTO and WIPO. Then we revised the literature including patents comprehensively on the planning and analysis of multistress ALT. Results: Optimal designs for MALT under different stress loadings are summarized, and different types of statistical inference methods are categorized and introduced. Finally, some challenges and research trends are discussed for future study.

Background: Nowadays, the manufacturing industry is much more fiercely competitive and global than ever before. For sustainable increases in market share and profitability, manufacturers are aiming to improve the quality of products and maintain the reliability of manufacturing systems. Objective: Therefore, to simultaneously optimize the quality and reliability for manufacturing systems has become an important research topic in recent years. Methods: This study presents an overview of the methods for modeling manufacturing systems, especially considering the system reliability and the product quality. And then, we review the optimization methods for manufacturing system maintenance and production strategy. Conclusion: Finally, optimization methods and some challenges are summarized for future studies.

Background: Modern medical researches show that the health of a population is closely related to their behavior, environmental factors, social and economic conditions, aging and genetic susceptibility. Therefore, it is very important to study the relationship between these factors and health of a population. Objective: This study reviews the latest research progress in population health management and life/disease risk assessment, analyzes the existing problems in relevant researches, and proposes some improvement plans to solve the problems. Methods: It also introduces the general methods of human health management and life/disease risk assessment, analyzes the defects in these methods in practical application, and then draws conclusions regarding industrial system equipment health management and residual life prediction, and puts forward some new ideas to solve the problems. Results: In the study of health assessment, although self-assessment of health is a common method of determining health variables, its subjectivity and inaccuracy are problems that cannot be ignored. In life/disease risk assessment studies, medical effect and efficacy are mainly evaluated, and little consideration is given to other factors, such as behaviour, environment, and socio-economic status. In the construction of statistical graphs, great individual differences, internal symbiotic variables and external impact variables are seldom considered. Conclusion: This study helps to understand the basic ideas and methods of health management and life/disease risk assessment, and proposes some future research programs based on the author's knowledge.

Background: In a multi-state system, either the entire system or its components will have more than two states. Different kind of multi-state systems have been investigated, such as multistate series-parallel systems, multi-state k-out-of-n systems and multi-state linear consecutive-k-outof- n systems. Methods: Performability analysis is concerned with the calculation of probability distribution of different system performance levels. In this paper, Multi-valued Decision Diagram (MDD) based approaches are discussed to conduct the performability analysis of multi-state systems. Results: Examples are provided to illustrate the use of MDD approaches for three types of multistate systems, e.g. multi-state series-parallel systems, multi-state k-out-of-n systems and multi-state linear consecutive-k-out-of-n systems. Conclusion: The empirical results show that the MDD approaches have lower computational complexity than the traditional methods in model generation and evaluation.

Background: Environmental protection is increasingly being emphasized upon, and higher requirements are put forward for the development of the geological prospecting industry. Researchers have been trying their best to explore the mineral resources in the deep part of the earth and the areas with poor working conditions, and avoid the damage of mining development to the environment, so as to achieve the goal of green prospecting and sustainable geological exploration. Methods: This greatly increases the uncertainty of ore prospecting and requires the traditional technical means to be improved. With the great progress of computer hardware and software, the application of geophysical exploration, geochemical exploration, remote sensing, and other methods that have little damage to the environment, have been improved. A reasonable technology mix can be used more efficiently and explored in a cost-effective way. Conclusion: According to the requirements of green and sustainable exploration, geophysical exploration, geochemical exploration and remote sensing can acquire surface data of a certain area more quickly with less economic cost and lower environmental impact, so as to provide decision for the next step of prospecting and avoid the risk to a greater extent. The prospecting information obtained by the three methods cannot directly control mine. The specific method selection and combination need to consider the actual demand, in order to complete the geological exploration work better and with rational use of funds.

Background: Oil well cement retarder is an additive that can extend time for thickening cement slurry, which can ensure the safety of cement. At present, the oil well cement retarder is mainly composed of synthetic materials, which are mainly divided into three major categories: compound polymer, AMPS polymer and non-AMPS. Methods: In this paper, the research status of synthetic oil well cement retarder in recent years is reviewed, and its shortcomings and development trends are analyzed. It is pointed out that the shortage of synthetic retarder mainly lies in problems, including large temperature sensitivity, small temperature application range, abnormal thickening curve, great influence on high temperature settlement stability and cement stone strength development. Conclusion: The development direction of oil well cement retarder is mainly focused on developing intelligent retarder and degradable retarder to meet the cementing needs of oilfields and ensure cementing effect increasing steadily.

Background: The purpose of this paper is to critically review the studies that deal with advanced product design techniques in order to identify the research gaps and provide recommendations for future research. Methods: To this end, a systematic review of literature on advanced product design techniques was conducted over a period of nearly ten years between 2010 and 2019, and a new model has been developed on the basis of insights from prior research. Results: Based on the extensive literature review, the authors identified key product design theories, methodologies, and several research clusters, in which product design techniques appear to hold particular promise in terms of capturing positive consumer behavior outcomes. Conclusion: To the best of the authors’ knowledge, the present review is the first of its kind to provide deeper insights into advanced analytical areas for future product design research (presented as propositions) aiming for high reliability.

Background: Remaining Useful Life (RUL) estimation is the central mission to the complex systems’ prognostics and health management. During the last decades, numbers of developments and applications of the RUL estimation have proliferated. Objective: As one of the most popular approaches, stochastic process-based approach has been widely used for characterizing the degradation trajectories and estimating RULs. This paper aimed at reviewing the latest methods and patents on this topic. Methods: The review is concentrated on four common stochastic processes for degradation modelling and RUL estimation, i.e., Gamma process, Wiener process, inverse Gaussian process and Markov chain. Results: After a brief review of these four models, we pointed out the pros and cons of them, as well as the improvement direction of each method. Conclusion: For better implementation, the applications of these four approaches on maintenance and decision-making are systematically introduced. Finally, possible future trends are concluded tentatively.

Background: Joint investment has increasingly become a popular investment method for venture capitalists. From the two traditional perspectives of investors and start-ups, research on Joint Venture Capital in the past 40 years has achieved rich results. Most recent literature is based on research from the perspective of organisational economics, which further advances the vertical development of research on Joint Venture Capital. Objective: The objective of this paper is to review research topics and core literature on Joint Venture Capital from the perspective of organisational economics, and through introducing the model of venture capitalists' ‘bounded rationality’ and evolutionary game in the joint investment risk analysis. This paper distinguishes the influence of the game model on the formation of joint investment. Finally, it reaches a conclusion and suggests a direction for future research. Methods: This paper finds and reviews literature on joint venture capital and dynamic game model of joint investment risk that is collated to reduce the actual risk assumed by each investor. Additionally, the paper summarises research topics and progress from the perspective of organisational economics to identify possible research directions for the future. Results: Based on the evolutionary game method for analysis of the model of joint investment, the following conclusion is drawn: the greater the heterogeneity of the participating entities, the smaller the unit conflict cost benefit and the greater the probability of successful joint venture investment. The joint investment operation mechanism will also be maintained on a long-term and stable manner. Conclusion: From the perspective of organisational economics, the latest research on Joint Venture Capital has extensively absorbed new research results of relevant disciplines. Joint Venture Capital activities can be understood from a broader perspective and with new insights, which reflect complex and dynamic interaction and correlative dependence on network members. To establish a more successful joint investment model, the paper introduces a relatively novel evolutionary game method for analysis of the joint investment model.

Background: The reform and innovation of recording technology have resulted in recording becoming an exciting, developing project. Against the background of Internet +, traditional analogue technology has developed into digital recording technology, playing an important role in various fields. Venture capital in digital recording technology projects has also attracted attention from all circles. Objective: This paper aims to, by sorting out literature on venture capital, analyze the measurement method of project investment risk, and then, after analyzing the risk factors existing in the investment of digital recording technology under the “Internet +”, propose measures to control these risk factors. At the same time, taking CY company as an example, the investment risk prevention strategy of digital recording technology project is applied to the risk investment evaluation practice of CY company. Methods: This paper reviews and comments the literature on venture capital, and sorts out the evaluation methods of project investment risk. After studying the project investment risk of digital recording technology, this paper finds out the preventive strategies to deal with these risks, and applies them to risk investment evaluation of CY. This paper proposes investment suggestions based on various factors, and makes an overall evaluation of the value of digital recording technology project, which hopefully will act as a reference for venture capital institutions when investing in digital recording technology in the future. Results: The countermeasures against investment risks in digital recording technology projects are: 1. Identification of countermeasures against investment risks in digital recording technology projects. 2. Encouragement and promotion of joint-stock cooperation and reduction of operational risks. 3. Establishment and improvement of financial risk control. Conclusion: Digital technology, which is continuously improving, has penetrated recording technology. With mindful awareness of investment risks and careful investment in recording technology projects, digital technology can improve living standards while making the flexibility and form of recording work more artistic and enabling recording technology to reach new heights.

Background: With the rapid development of computer and Internet technologies, the measurement of software reliability has become a key point. Software reliability modeling is an important way to measure software reliability. However, there are many disadvantages in the classic model. Therefore, this paper reviews current researches in software reliability and discusses ways to improve the model from a new perspective. Objective: This paper reviews the current researches on software reliability, analyzes the existing patented technology, and points out some future directions to improve the current models to provide a more accurate and efficient way for software reliability measurement. Methods: This study introduces the general methods of software reliability evaluation, analyzes the disadvantages of these methods in practical application, draws lessons from the patent, and puts forward some new ideas to solve the problems. Results: Disadvantages of current researches are identified based on literature review. In addition, two suggestions are given to improve the current models. Conclusion: Although the software reliability has made great progress, there are still many things to be studied in the future. The problems of software reliability in real life should be gradually solved.

Background: In this paper, a two-pole 3 kW three-phase induction motor is taken as an example to establish a two-dimensional finite element model. The correctness of the model is verified by comparing the finite element calculation data with the experimental data. Methods: On this basis, the influence of electromagnetic characteristics of different shell materials on the motor yoke saturation degree, loss, current and power factor are studied, it is determined that the motor yoke saturation degree is the key factor affecting the power factor, current and loss of the motor. The influence of different stator yoke thickness on the saturation degree of motor stator yoke with the same shell material is further studied. The influences of motor stator yoke saturation degree on motor current, loss and power factor are obtained when the stator yoke thickness is different. Results: The optimum range of motor current, loss and power factor is obtained. Conclusion: Finally, by comparing the different shell materials to optimize the motor structure size, it is determined that the motor stator yoke thickness can be reduced by using cast iron shell, and the motor materials consumption can be saved to provide reference for motor optimization design.

Background: In the production process of apple orchard, the labor needed for apple harvest accounts about 40% of the whole production process. Objective: The auxiliary device of apple harvest was designed to improve production efficiency and reduce labor cost. Methods: This device was composed of four parts: fruit collecting mechanism, horizontal conveying mechanism, vertical conveying mechanism and rotary packing mechanism, which assists farmers in finishing the process from picking to packaging apples. Simulation and fruit damage analyses were carried out by Solid works, fruit damage included three types: Single collision, Overlapping collision and Multi-zone collision. Results: In the experiment, PID algorithm was employed to control device operate accurately. And when the motor speed were 52 r/min, 56 r/min, 60 r/min, the collection efficiency were 4900 apples/ h, 5300 apples/h, 5700 apples/h and the fruit damage rates were 4%, 5%, 8%. Conclusion: The experimental results indicated that compared with the manual operation and visual recognition-based picking robots this device’s production efficiency was improving without increasing the fruit damage rate.