Zhi Zheng, Guangjun Li and Yunlong Teng
The purpose of this paper is to develop a new method for the two‐dimensional direction‐of‐arrival (DOA) estimation of multiple coherently distributed (CD) sources, which can…
Abstract
Purpose
The purpose of this paper is to develop a new method for the two‐dimensional direction‐of‐arrival (DOA) estimation of multiple coherently distributed (CD) sources, which can provide lower computational complexity while sustaining the estimation performance within a tolerable level.
Design/methodology/approach
Using three parallel uniform linear arrays (ULAs), a new method for parametric estimation of multiple coherently distributed sources is proposed. The proposed method is based on the Taylor approximation to the generalized steering vectors (GSVs) of shifted ULAs, and utilizes the special array geometry. In addition, a simple parameter matching procedure is also given in this paper.
Findings
Several numerical experiments have been designed. The experiments are based on coherently distributed source model, and the noise is assumed to be zero‐mean and spatially and temporally white and Gaussian. Numerical results show that the proposed method can exhibit good estimation performance under small angular spread and be applicable to the multisource scenario with different angular distributions.
Research limitations/implications
This research is limited to CD sources. Furthermore, the proposed method is based on the small angular approximation to GSV. Hence, it is fitter for the case of small angular extension.
Originality/value
Without any spectrum‐peak searching, the proposed method provides lower computational cost compared to the classical spectrum‐based methods. Moreover, it does not depend on the prior knowledge about angular distribution shape and is hence robust to mismodeling.
Details
Keywords
Zhiguang Cheng, Behzad Forghani, Zhenbin Du, Lanrong Liu, Yongjian Li, Xiaojun Zhao, Tao Liu, Linfeng Cai, Weiming Zhang, Meilin Lu, Yakun Tian and Yating Li
This paper aims to propose and establish a set of new benchmark models to investigate and confidently validate the modeling and prediction of total stray-field loss inside…
Abstract
Purpose
This paper aims to propose and establish a set of new benchmark models to investigate and confidently validate the modeling and prediction of total stray-field loss inside magnetic and non-magnetic components under harmonics-direct current (HDC) hybrid excitations. As a new member-set (P21e) of the testing electromagnetic analysis methods Problem 21 Family, the focus is on efficient analysis methods and accurate material property modeling under complex excitations.
Design/methodology/approach
This P21e-based benchmarking covers the design of new benchmark models with magnetic flux compensation, the establishment of a new benchmark measurement system with HDC hybrid excitation, the formulation of the testing program (such as defined Cases I–V) and the measurement and prediction of material properties under HDC hybrid excitations, to test electromagnetic analysis methods and finite element (FE) computation models and investigate the electromagnetic behavior of typical magnetic and electromagnetic shields in electrical equipment.
Findings
The updated Problem 21 Family (V.2021) can now be used to investigate and validate the total power loss and the different shielding performance of magnetic and electromagnetic shields under various HDC hybrid excitations, including the different spatial distributions of the same excitation parameters. The new member-set (P21e) with magnetic flux compensation can experimentally determine the total power loss inside the load-component, which helps to validate the numerical modeling and simulation with confidence. The additional iron loss inside the laminated sheets caused by the magnetic flux normal to the laminations must be correctly modeled and predicted during the design and analysis. It is also observed that the magnetic properties (B27R090) measured in the rolling and transverse directions with different direct current (DC) biasing magnetic field are quite different from each other.
Research limitations/implications
The future benchmarking target is to study the effects of stronger HDC hybrid excitations on the internal loss behavior and the microstructure of magnetic load components.
Originality/value
This paper proposes a new extension of Problem 21 Family (1993–2021) with the upgraded excitation, involving multi-harmonics and DC bias. The alternating current (AC) and DC excitation can be applied at the two sides of the model’s load-component to avoid the adverse impact on the AC and DC power supply and investigate the effect of different AC and DC hybrid patterns on the total loss inside the load-component. The overall effectiveness of numerical modeling and simulation is highlighted and achieved via combining the efficient electromagnetic analysis methods and solvers, the reliable material property modeling and prediction under complex excitations and the precise FE computation model using partition processing. The outcome of this project will be beneficial to large-scale and high-performance numerical modeling.
Details
Keywords
- New member-set
- TEAM Problem 21 Family
- Overall effectiveness
- Harmonics-DC hybrid excitation
- Magnetic flux compensation
- Load-component
- Shielding
- Stray-field loss
- Additional loss
- Material property under complex excitations
- Electromagnetic fields
- Numerical analysis
- Power losses
- Transient analysis
- Material modeling
- Computational electromagnetics
Linwei Li, Gang Wang, Mi Che and Yun-Long Pei
The research is aimed at investigating how relational mechanisms and formal contracts affect alliance success under constructive and destructive conflict.
Abstract
Purpose
The research is aimed at investigating how relational mechanisms and formal contracts affect alliance success under constructive and destructive conflict.
Design/methodology/approach
While relational mechanisms and formal contracts are widely used in strategic alliances to manage a variety of issues among partners, recent research has indicated that effects of these governance mechanisms may change in distinct contexts. Adopting the lens of new institutional economics, this study provides insights on the comparative and interactive effects of relational mechanisms and formal contracts on alliance success, and the differential contingency effects of two types of inter-partner conflict, i.e. constructive and destructive conflict, on the above relationships. The authors use hierarchical multivariate regression analyses through a survey dataset of 392 alliance firms in China with the approach of two key informants.
Findings
The empirical results confirm that relational mechanisms have a stronger positive effect on alliance success than formal contracts and these two governance mechanisms complement each other in driving alliance success. When facing a high level of constructive conflict, partner firms rely to a greater extent on relational mechanisms than on formal contracts to achieve alliance success. When a high level of destructive conflict exists, partner firms depend more heavily on formal contracts than on relational mechanisms to achieve alliance success. Moreover, the complementary effect of the two governance mechanisms is much stronger when partner firms face high constructive conflict than when they face high destructive conflict.
Originality/value
This study discloses the comparative and interactive effects of relational mechanisms and formal contracts on alliance success in distinct contexts by identifying the moderating roles of constructive and destructive conflict.
Details
Keywords
Zhenhua Quan, Wenjie Qian and Jianhua Mao
The purpose of this article is to explore the relationship between the attributes of Olympic mascots and their impact on sponsorship effectiveness. Based on a multiattribute model…
Abstract
Purpose
The purpose of this article is to explore the relationship between the attributes of Olympic mascots and their impact on sponsorship effectiveness. Based on a multiattribute model and the introduction of engagement theory and the meaning transfer model, this article uses the 2022 Beijing Winter Olympics mascot “Bing Dwen Dwen” as the research object to empirically analyze the effects and mechanisms of the mascot's attributes on preference, event engagement, sponsorship enterprise trust and sponsorship enterprise attitude, ultimately constructing a sponsorship effectiveness model.
Design/methodology/approach
The survey method was used to examine 238 respondents' emotions and attitudes towards companies participating in sponsoring Olympic mascots.
Findings
The study found that the main attributes of the mascot include visual and emotional factors, both of which have a positive impact on preference, with emotional factors having a greater influence than visual factors. Visual and emotional factors indirectly affect engagement through preference. Preference and engagement play a completely mediating role in the effect of mascot attributes on sponsorship enterprise trust and sponsorship enterprise attitude.
Practical implications
This study provides practical recommendations for managers to achieve marketing success in sports sponsorship through mascots.
Originality/value
This paper provides a measurement tool for the study of mascot attributes and important support for subsequent research in sponsorship marketing.