Lijun Shang, Qingan Qiu, Cang Wu and Yongjun Du
The study aims to design the limited number of random working cycle as a warranty term and propose two types of warranties, which can help manufacturers to ensure the product…
Abstract
Purpose
The study aims to design the limited number of random working cycle as a warranty term and propose two types of warranties, which can help manufacturers to ensure the product reliability during the warranty period. By extending the proposed warranty to the consumer's post-warranty maintenance model, besides the authors investigate two kinds of random maintenance policies to sustain the post-warranty reliability, i.e. random replacement first and random replacement last. By integrating depreciation expense depending on working time, the cost rate is constructed for each random maintenance policy and some special cases are provided by discussing parameters in cost rates. Finally, sensitivities on both the proposed warranty and random maintenance policies are analyzed in numerical experiments.
Design/methodology/approach
The working cycle of products can be monitored by advanced sensors and measuring technologies. By monitoring the working cycle, manufacturers can design warranty policies to ensure product reliability performance and consumers can model the post-warranty maintenance to sustain the post-warranty reliability. In this article, the authors design a limited number of random working cycles as a warranty term and propose two types of warranties, which can help manufacturers to ensure the product reliability performance during the warranty period. By extending a proposed warranty to the consumer's post-warranty maintenance model, the authors investigate two kinds of random replacement policies to sustain the post-warranty reliability, i.e. random replacement first and random replacement last. By integrating a depreciation expense depending on working time, the cost rate is constructed for each random replacement and some special cases are provided by discussing parameters in the cost rate. Finally, sensitivities to both the proposed warranties and random replacements are analyzed in numerical experiments.
Findings
It is shown that the manufacturer can control the warranty cost by limiting number of random working cycle. For the consumer, when the number of random working cycle is designed as a greater warranty limit, the cost rate can be reduced while the post-warranty period can't be lengthened.
Originality/value
The contribution of this article can be highlighted in two key aspects: (1) the authors investigate early warranties to ensure reliability performance of the product which executes successively projects at random working cycles; (2) by integrating random working cycles into the post-warranty period, the authors is the first to investigate random maintenance policy to sustain the post-warranty reliability from the consumer's perspective, which seldom appears in the existing literature.
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China's increasing income inequality might cause a series of problems, such as the slowdown of economic growth, social and economic tension, the decline of the ecological…
Abstract
Purpose
China's increasing income inequality might cause a series of problems, such as the slowdown of economic growth, social and economic tension, the decline of the ecological environment quality and the threat to citizens' health. Consequently, income inequality will inevitably affect the ecological well-being performance (EWP) level of China's provinces through the above aspects. Analyzing the impact of income inequality on EWP and its spatial spillover effects are conducive to improving the level of EWP in China. Therefore, the research purpose of this paper is to use China's provincial data from 2001 to 2017 to analyze the impact of income inequality on EWP and the spatial spillover effect based on the evaluation of the EWP value of each province.
Design/methodology/approach
At first, this study utilizes the super efficiency slacks-based measure model (Super-SBM model) to calculate the EWP values of 30 provinces in China, which can evaluate and rank the effective decision units in the SBM model and make up for the defect that the effective decision units cannot be distinguished. Then this study applies the spatial Durbin model and Tobit regression model (SDM-Tobit model) to explore the impact of income inequality and other influencing factors on EWP and the spatial spillover effects in adjacent areas.
Findings
Firstly, the average EWP in China fluctuated slightly and showed a downward trend from 2001 to 2017. In addition, the EWP values of the provinces in the western region are usually weaker than those in the eastern and central regions. Moreover, income inequality is negatively correlated with EWP, and the EWP has a spatial spillover effect, which means the EWP level in a region is affected by EWP values in the adjacent regions. Furthermore, the industrial structure and urbanization level are both negatively related to EWP, while technology level, investment openness, trade openness and education level are positively related to EWP.
Originality/value
Compared with the existing research, the possible contribution of this research is that it takes income inequality as one of the important influencing factors of EWP and adopts the SDM-Tobit model to analyze the impact mechanism of income inequality on EWP from the perspective of time and space, providing new ideas for improving the EWP of various provinces in China.
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Lijun Chao, Zhi Xiong, Jianye Liu, Chuang Yang and Yudi Chen
To solve problems of low intelligence and poor robustness of traditional navigation systems, the purpose of this paper is to propose a brain-inspired localization method of the…
Abstract
Purpose
To solve problems of low intelligence and poor robustness of traditional navigation systems, the purpose of this paper is to propose a brain-inspired localization method of the unmanned aerial vehicle (UAV).
Design/methodology/approach
First, the yaw angle of the UAV is obtained by modeling head direction cells with one-dimension continuous attractor neural network (1 D-CANN) and then inputs into 3D grid cells. After that, the motion information of the UAV is encoded as the firing of 3 D grid cells using 3 D-CANN. Finally, the current position of the UAV can be decoded from the neuron firing through the period-adic method.
Findings
Simulation results suggest that continuous yaw and position information can be generated from the conjunctive model of head direction cells and grid cells.
Originality/value
The proposed period-adic cell decoding method can provide a UAV with the 3 D position, which is more intelligent and robust than traditional navigation methods.
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During the decade of the 1980s, the design and implementation ofeconomic reforms had divided the Chinese leadership into two factions:conservative proponents of moderation and…
Abstract
During the decade of the 1980s, the design and implementation of economic reforms had divided the Chinese leadership into two factions: conservative proponents of moderation and “circumscribed” economic reform, and liberal proponents of comprehensive and rapid economic and social reform. Seeks to identify the economic‐theoretic core of leftist and rightist positions. The leftist position described is centred on the works of Chen Yun, Sun Yefang, and Zue Muqiao and explicitly excludes the idealistic and revolutionary political theories of Maoism, focuses instead on the more pragmatic goals of rational central economic planning. The rightist position became identified with Zhao Ziyang and his vision of mixed market socialism which, in the minds of his opponents, came dangerously close to capitalism. As the Chinese economy faltered toward the end of the decade, the conflict between leftist hard‐line conservatives and rightist liberals heightened, leading to the pro‐democracy movement of 1989 and its aftermath.
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Lijun Meng, Jingya Xue, Baoyou Zhang and Hongying Xia
This study attempts to determine the optimal pricing and warranty strategies for remanufactured products offered by independent remanufacturers (IRs). Specifically, it takes into…
Abstract
Purpose
This study attempts to determine the optimal pricing and warranty strategies for remanufactured products offered by independent remanufacturers (IRs). Specifically, it takes into account price competition and warranty service competition between the original equipment manufacturer (OEM) and IR, ultimately providing recommendations on the selection of warranty service modes for IRs.
Design/methodology/approach
This study considers two warranty modes for IRs: in-housing and outsourcing. Based on game theory, this study identifies the conditions under which the warranty service for remanufactured product is outsourced to retailers in IR-remanufacturing mode. Furthermore, this study investigates how this strategic decision affects closed-loop supply chain (CLSC) operations by comparing the two modes in terms of profit, consumer surplus (CS), quantity and overall social welfare (SW).
Findings
Firstly, the provision strategy for IRs' warranty on remanufactured products depends mainly on the retailer’s warranty cost. If retailers have lower costs for warranties, IR opts to outsource the remanufactured product warranty to the retailer. Second, when retailers offer warranties at a lower cost, IRs prefer outsourcing remanufactured product warranty to retailers. In this way, it will maximize both the remanufacturer’s and retailer’s profits while achieving the optimal total profit for the entire supply chain. However, it’s not beneficial for the OEM. Third, the IR’s preference for warranty service provision strategy is influenced by customers’ acceptance of remanufactured product, customer sensitivity toward remanufactured product warranty and economies of scale in warranty service.
Practical implications
The findings offer operational insights into IR decision-making in selecting warranty service provision strategies for remanufactured products.
Originality/value
This study is among the first to examine warranty provision strategy for IRs in CLSC.
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The present study provides a comprehensive review of the advancements in five active heating modes for cold-proof clothing as of 2021. It aims to evaluate the current state of…
Abstract
Purpose
The present study provides a comprehensive review of the advancements in five active heating modes for cold-proof clothing as of 2021. It aims to evaluate the current state of research for each heating mode and identify their limitations. Further, the study provides insights into the optimization of intelligent temperature control algorithms and design considerations for intelligent cold-proof clothing.
Design/methodology/approach
This article presents a classification of active heating systems based on five different heating principles: electric heating system, solar heating system, phase-change material (PCM) heating system, chemical heating system and fluid/air heating system. The systems are analyzed and evaluated in terms of heating principle, research advancement, scientific challenges and application potential in the field of cold-proof clothing.
Findings
The rational utilization of active heating modes enhances the thermal efficiency of cold-proof clothing, resulting in enhanced cold-resistance and reduced volume and weight. Despite progress in the development of the five prevalent heating modes, particularly with regard to the improvement and advancement of heating materials, the current integration of heating systems with cold-proof clothing is limited to the torso and limbs, lacking consideration of the thermal physiological requirements of the human body. Additionally, the heating modes of each system tend to be uniform and lack differentiation to meet the varying cold protection needs of various body parts.
Research limitations/implications
The effective application of multiple heating modes helps the human body to maintain a constant body temperature and thermal equilibrium in a cold environment. The research of heating mode is the basis for realizing the temperature control of cold-proof clothing and provides an effective guarantee for the future development of the intelligent algorithms for temperature control of non-uniform heating of body segments.
Practical implications
The integration of multiple heating modes ensures the maintenance of a constant body temperature and thermal balance for the wearer in cold environments. The research of heating modes forms the foundation for the temperature regulation of cold-proof clothing and lays the groundwork for the development of intelligent algorithms for non-uniform heating control of different body segments.
Originality/value
The present article systematically reviews five active heating modes suitable for use in cold-proof clothing and offers guidance for the selection of heating systems in future smart cold-proof clothing. Furthermore, the findings of this research provide a basis for future research on non-uniform heating modes that are aligned with the thermal physiological needs of the human body, thus contributing to the development of cold-proof clothing that is better suited to meet the thermal needs of the human body.