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Article
Publication date: 3 April 2019

Shuaian Wang, Ran Yan, Lingxiao Wu and Dong Yang

The purpose of this study is to propose a mathematical optimization model to solve the yacht mooring area re-allocation problem (YMARP). The objective of the problem is to…

Abstract

Purpose

The purpose of this study is to propose a mathematical optimization model to solve the yacht mooring area re-allocation problem (YMARP). The objective of the problem is to allow the maximum number of yachts to be moored at their ideal mooring areas.

Design/methodology/approach

In this paper, the YMARP is introduced, formally defined and discussed. The authors develop a 0-1 integer programing optimization model for the problem, which can be solved efficiently using off-shelf solvers. The performance of the model is tested on extensive numerical experiments.

Findings

The results of the numerical experiments demonstrate that the proposed model can solve the YMARP very efficiently using off-shelf solvers like CPLEX. In particular, problems with up to 30,000 yachts and 400 mooring areas can be solved to optimum within 30 s.

Originality/value

This study is one of the preliminary studies to consider problems arising in yacht management in a quantitative manner. The proposed model has three main merits. First, it enables the government to better manage yachts and mooring areas. Second, with more yacht owners assigned with ideal mooring areas, the model helps reduce the traveling time of the yacht owners to yacht mooring areas. Third, by reducing the traveling time of the yacht owners, the model contributes to lessening the traffic burden in cities.

Details

Maritime Business Review, vol. 4 no. 1
Type: Research Article
ISSN: 2397-3757

Keywords

Article
Publication date: 2 January 2018

Dong Yang, Zhenxiang Liu, Ting Shu, Lijia Yang, Jianming Ouyang and Shen Zhi

Helical coil electromagnetic launchers (HEMLs) using motion-induced commutation strategy solve the problem of synchronization control perfectly. HEMLs can meet the…

Abstract

Purpose

Helical coil electromagnetic launchers (HEMLs) using motion-induced commutation strategy solve the problem of synchronization control perfectly. HEMLs can meet the requirements of multiple applications such as the electromagnetic catapult, electromagnetic mortar and high-velocity coilgun. The trade-off between the velocity and efficiency is an important basis for these different applications. To optimize such objectives before actual design, the purpose of this paper is to focus on the efficient and flexible calculation model and algorithm. A novel structure of HEML is proposed after the transient simulation by this algorithm, which can improve the energy conversion efficiency and suppress the muzzle arc without affecting the velocity too much.

Design/methodology/approach

The equivalent circuit model of the launcher is established and the governing equations are derived. A combination of the four-stage Runge–Kutta method and the trapezoidal quadrature formula are used to solve the governing equations.

Findings

With smaller number of turns in the coils of HEML, the velocity is larger and the efficiency is lower. The non-uniform HEML is an effective option to improve the energy conversion efficiency and to suppress the muzzle arc with almost the same muzzle velocity as the conventional HEML.

Originality/value

The paper presents a common model and a flexible fast numerical method which can be used in multi-objective optimization of HEMLs such as the genetic algorithm. A new structure of the non-uniform HEML is proposed to improve the energy conversion efficiency and to suppress the muzzle arc of the launcher.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 37 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 6 June 2022

Jianzhong Ding, Xueao Liu, Yang Dong and Chunjie Wang

The purpose of this paper is to study the landing performance of the Mars lander considering uncertain landing conditions under two landing modes.

Abstract

Purpose

The purpose of this paper is to study the landing performance of the Mars lander considering uncertain landing conditions under two landing modes.

Design/methodology/approach

A dynamics analysis model for the legged Mars lander is established for landing simulation, where the nonlinear large-deformation flexible buffer rods are equivalently modeled with a rigid-body mechanism with external forces and movement limit. Sensitivities of the landing stability to various landing conditions are analyzed using the Quasi–Monte-Carlo-based Sobol’ method and computer-aided landing simulations. Moreover, based on the results of sensitivity analysis, sensitive parameters are selected for estimating the safe boundaries for stability indices of rotation and clearance.

Findings

It can be concluded from this study that the lander has excellent ability against overturning. The shutdown-before-touchdown strategy helps to maintain than landing pose, and the shutdown-at-touchdown strategy helps to prevent the nozzle from colliding with the surface of Mars.

Practical implications

This study provides a theoretical reference to choose the better landing strategies for Mars landers considering uncertain landing conditions.

Originality/value

A parameterized dynamics Mars lander model and a simplification method are proposed to simulate the landing on Mars. Uncertain landing conditions are parameterized and considered in the dynamics model. Sensitivity analysis and safe boundary methods are used to compare the landing performances with two landing strategies.

Details

Aircraft Engineering and Aerospace Technology, vol. 94 no. 10
Type: Research Article
ISSN: 1748-8842

Keywords

Article
Publication date: 27 March 2020

Dong Yang, Zelong Wei, Huibin Shi and Jie Zhao

This study aims to investigate how market orientation (MO) motivates firms to develop business model innovation and how such effects are moderated by strategic flexibility.

1330

Abstract

Purpose

This study aims to investigate how market orientation (MO) motivates firms to develop business model innovation and how such effects are moderated by strategic flexibility.

Design/methodology/approach

In this study, a questionnaire-based survey was undertaken to test the proposed hypotheses. The empirical study was conducted on a sample of 204 firms using two key informants (408 respondents) in China. The regression model is used to test the proposed model.

Findings

This research finds that both responsive market orientation (RMO) and proactive market orientation (PMO) have a positive effect on business model innovation. The effects of RMO and PMO on business model innovation are contingent on resource (coordination) flexibility in different ways. More importantly, this study finds that resource flexibility enhances the positive effect of RMO and weakens the positive effect of PMO. The study also finds that coordination flexibility enhances the positive effect of PMO.

Research limitations/implications

Future research can explore the internal mechanisms through which RMO and PMO promote business model innovations. Although the study finds that both the MOs promote business model innovation, they may promote business model innovation through different mediating effects. Future research can explore the role of external dynamic capabilities. This research mainly focuses on the internal dynamic capability of focal firms. However, as a focal firm-centered boundary spanning activity system, to transform into a new business model, firms not only need to reconfigure internal resource base, but also need to realign external collaboration network.

Practical implications

This research also bears important managerial implications. First, firms should be aware of the positive effect of MO on business model innovation. Firms with higher level of RMO or PMO can promote business model innovation. Second, when firms implement RMO for business model innovation, managers should focus on resource flexibility. Where MO is responsive, marketing managers need to be concerned with ensuring various applications of existing resource so as to understand effectively the current customers and market domain. Third, to leverage PMO for business model innovation, firms should adopt coordination flexibility. For firms with higher level PMO, firms should try to find the new internal coordination process for customer latent needs.

Originality/value

The conclusion extends the business model innovation research from the view of dynamic capabilities. As one of types of dynamic capabilities, MO is also the important antecedent of business model innovation. Further, this research also discusses the role strategic flexibility plays in business model innovation.

Details

Journal of Business & Industrial Marketing, vol. 35 no. 4
Type: Research Article
ISSN: 0885-8624

Keywords

Article
Publication date: 22 October 2021

Na Pang, Li Qian, Weimin Lyu and Jin-Dong Yang

In computational chemistry, the chemical bond energy (pKa) is essential, but most pKa-related data are submerged in scientific papers, with only a few data that have been…

Abstract

Purpose

In computational chemistry, the chemical bond energy (pKa) is essential, but most pKa-related data are submerged in scientific papers, with only a few data that have been extracted by domain experts manually. The loss of scientific data does not contribute to in-depth and innovative scientific data analysis. To address this problem, this study aims to utilize natural language processing methods to extract pKa-related scientific data in chemical papers.

Design/methodology/approach

Based on the previous Bert-CRF model combined with dictionaries and rules to resolve the problem of a large number of unknown words of professional vocabulary, in this paper, the authors proposed an end-to-end Bert-CRF model with inputting constructed domain wordpiece tokens using text mining methods. The authors use standard high-frequency string extraction techniques to construct domain wordpiece tokens for specific domains. And in the subsequent deep learning work, domain features are added to the input.

Findings

The experiments show that the end-to-end Bert-CRF model could have a relatively good result and can be easily transferred to other domains because it reduces the requirements for experts by using automatic high-frequency wordpiece tokens extraction techniques to construct the domain wordpiece tokenization rules and then input domain features to the Bert model.

Originality/value

By decomposing lots of unknown words with domain feature-based wordpiece tokens, the authors manage to resolve the problem of a large amount of professional vocabulary and achieve a relatively ideal extraction result compared to the baseline model. The end-to-end model explores low-cost migration for entity and relation extraction in professional fields, reducing the requirements for experts.

Details

Data Technologies and Applications, vol. 56 no. 2
Type: Research Article
ISSN: 2514-9288

Keywords

Book part
Publication date: 20 January 2021

Yao Lixia

Abstract

Details

Energy Security in Times of Economic Transition: Lessons from China
Type: Book
ISBN: 978-1-83982-465-4

Article
Publication date: 14 September 2018

De-Cheng Feng, Cheng-Dong Yang and Xiao-Dan Ren

This paper aims to present a multi-scale stochastic damage model (SDM) for concrete and apply it to the stochastic response analysis of reinforced concrete shear wall structures.

Abstract

Purpose

This paper aims to present a multi-scale stochastic damage model (SDM) for concrete and apply it to the stochastic response analysis of reinforced concrete shear wall structures.

Design/methodology/approach

The proposed SDM is constructed at two scales, i.e. the macro-scale and the micro-scale. The general framework of the SDM is established on the basis of the continuum damage mechanics (CDM) at the macro-scale, whereas the detailed damage evolution is determined through a parallel fiber buddle model at the micro-scale. The parallel buddle model is made up of micro-elements with stochastic fracture strains, and a one-dimensional random field is assumed for the fracture strain distribution. To represent the random field, a random functional method is adopted to quantify the stochastic damage evolution process with only two variables; thus, the numerical efficiency is greatly enhanced. Meanwhile, the probability density evolution method (PDEM) is introduced for the structural stochastic response analysis.

Findings

By combing the SDM and PDEM, the probabilistic analysis of a shear wall structure is performed. The mean value, standard deviation and the probability density function of the shear wall responses, e.g., shear capacity, accumulated energy consumption and damage evolution, are obtained.

Originality/value

It is noted that the proposed method can reflect the influences of randomness from material level to structural level, and is efficient for stochastic response determination of shear wall structures.

Details

Engineering Computations, vol. 35 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Content available
Article
Publication date: 25 April 2016

Dong Yang, Jinxian Weng and Jia Hu

Shaanxi, Shanxi province and Inner Mongolia in north China are the nation’s leading producers of coal. In the past decades, a huge amount of coal has been transported from…

3304

Abstract

Purpose

Shaanxi, Shanxi province and Inner Mongolia in north China are the nation’s leading producers of coal. In the past decades, a huge amount of coal has been transported from these areas to the central and south China via ports in Hebei Province and Port of Tianjin. Traditionally, coal is transported in bulk shipment. However, in recent years, an interesting phenomenon is that the lump coal is sorted out in the north and then moved in containers to the south. This paper aims to ascertain whether the coal containerization will become an alternative transport mode for moving lump coal from the north to the south of China. Based on extensive field investigation and data analyses, it is found that although the container mode appears to be more expensive than the bulk shipping mode, the cost difference between the two modes is not as significant as our expectation if we also take into factors like fragmented demand, environment pressure, geographic distribution characteristics of customers and so on.

Design/methodology/approach

Extensive field investigation, data analysis and economic decision model.

Findings

It is found that although the container mode appears to be more expensive than the bulk shipping mode, the cost difference between the two modes is not as significant as the authors’ expectation if they also take into factors like fragmented demand, environment pressure, geographic distribution characteristics of customers and so on.

Originality/value

Although the major focus has been placed on the food containerization, the coal containerization is still a new thing and has attracted only limited attention. This paper is making an initial attempt to profile the phenomenon of coal containerization in China. This attempt is believed to not only enrich the literature of coal containerization but also support the literature of bulk containerization.

Details

Maritime Business Review, vol. 1 no. 1
Type: Research Article
ISSN: 2397-3757

Keywords

Article
Publication date: 1 October 2019

Jingbei Wang, Naiding Yang and Min Guo

This paper aims to propose the following questions: How does dynamic positioning influence organization’s innovation performance? Does knowledge base mediate the…

Abstract

Purpose

This paper aims to propose the following questions: How does dynamic positioning influence organization’s innovation performance? Does knowledge base mediate the relationship between them?

Design/methodology/approach

The empirical setting of this study is the smartphone collaboration network from 2004 to 2017; the authors selected one-site schemes and data of patents from the Derwent Innovation Database. Furthermore, the authors adopted the negative binomial model with random effects to test the hypotheses.

Findings

The regression results show that organization’s dynamic positioning has an inverted-U-shaped relationship with its exploratory innovation. Similarly, organization’s dynamic positioning has an inverted-U-shaped relationship with its exploitative innovation. Besides, knowledge base mediates the relationship between dynamic positioning and organization’s innovation performance.

Originality/value

This study empirically confirms the relationship between dynamic positioning and organization’s innovation performance by separately examining exploratory and exploitative innovation. Furthermore, this study provides a contribution to the literature linking dynamic positioning and organization’s innovation performance by investigating the mediating role of knowledge base.

Details

Journal of Business & Industrial Marketing, vol. 35 no. 5
Type: Research Article
ISSN: 0885-8624

Keywords

Article
Publication date: 20 February 2019

Guisheng Gan, Da-quan Xia, Xin Liu, Cong Liu, Hanlin Cheng, Zhongzhen Ming, Haoyang Gao, Dong-hua Yang and Yi-ping Wu

With continuous concerning on the toxic of element Pb, Pb-free solder was gradually used to replace traditional Sn-Pb solder. However, during the transition period from…

Abstract

Purpose

With continuous concerning on the toxic of element Pb, Pb-free solder was gradually used to replace traditional Sn-Pb solder. However, during the transition period from Sn-Pb to Pb-free solder, mixing of Sn-Pb and Pb-free is inevitable occurred in certain products, and in China where Sn-Pb solder was still used extensively in certain areas especially. Correspondingly, understanding reliability of Sn-Pb solder joints was very important, and further studies were needed.

Design/methodology/approach

Thermal shock test between −55°C and 125 °C was conducted on Sn-37Pb solder bumps in the BGA package to investigate the microstructure evolution and the growth mechanism of interfacial intermetallic compound (IMC) layer. The effects of thermal shock on the mechanical property and fracture behavior of Sn-37Pb solder bumps were discussed.

Findings

Pb-rich phase was coarsened and voids were increased at first; Pb-rich phase was refined and voids were decreased secondly with the increase of thermal shock cycles; the shear strength of solder bumps was slightly decreased after thermal shock, but was back up to 73.67MPa at 2,000 cycles; interfacial IMCs of solder bumps was from typical scallop-type into smooth, the composition of IMCs was from Cu6Sn5 into Cu6Sn5 and Cu3Sn after thermal shock with 1,500 and 2,000 cycles; 20.0 per cent of solder bumps at 1,500 cycles and 9.5 per cent of solder bumps at 2,000 cycles were failure respectively.

Originality/value

Compared with the board level test method, the impact shear test for the single solder bump is more convenient and economical and is actively pursued by the industries. The shear strength of solder bumps was slightly decreased after thermal shock, but was back up to 73.67 MPa at 2,000 cycles; 20.0 per cent of solder bumps at 1,500 cycles and 9.5 per cent of solder bumps at 2,000 cycles were failure.

Details

Soldering & Surface Mount Technology, vol. 31 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

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