Jincan Zhang, Min Liu, Jinchan Wang and Kun Xu
High-speed Indium Phosphide (InP) HBTs have been widely used to design high-speed analog, digital and mixed-signal integrated circuits. The purpose of this study is to propose a…
Abstract
Purpose
High-speed Indium Phosphide (InP) HBTs have been widely used to design high-speed analog, digital and mixed-signal integrated circuits. The purpose of this study is to propose a new parameter extraction procedure for determining an improved T-topology small-signal equivalent circuit of InP heterojunction bipolar transistors (HBTs).
Design/methodology/approach
The alternating current crowding effect is considered through adding the intrinsic base capacitance in the small-signal equivalent circuit. All of the circuit parameters are extracted directly without using any approximation.
Findings
The extraction technique is more easily understood and clearer than other extraction methods, as the equations are derived from the S-parameters by peeling peripheral elements from small-signal models to get reduced ones and extracting each equivalent-circuit parameter using each equation.
Originality/value
To validate the presented parameter extraction technology, an n-p-n emitter-up InP HBT was analyzed adopting the method. Excellent agreement between measured and modeled S-parameters is obtained up to 40 GHz.
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Nengchao Lv, Xinping Yan, Kun Xu and Chaozhong Wu
The purpose of this paper is to propose a bi‐level programming optimization model to reduce traffic congestion of transportation network while evacuating people to safe shelters…
Abstract
Purpose
The purpose of this paper is to propose a bi‐level programming optimization model to reduce traffic congestion of transportation network while evacuating people to safe shelters during disasters or special events.
Design/methodology/approach
The previous optimization model for contra flow configuration only considered the character of the manager. However, the traffic condition is not only controlled by managers, but also depended on the root choice of travelers. A bi‐level programming optimization model, which considered managers and evacuees' character, is proposed to optimize the contra flow of transportation network in evacuation during special events. The upper level model aims to minimize the total evacuation time, while the lower level based on user equilibrium assignment. A solution method based on discrete particle swarm optimization and Frank‐Wolfe algorithm is employed to solve the bi‐level programming problem.
Findings
It is found that the bi‐level programming based contra flow optimization model can improve evacuation efficiency and decrease evacuation time 30 per cent or more. With the increase of traffic demand, the evacuation time will decrease significantly by contra flow configuration.
Research limitations/implications
In the optimization model, the background traffic is ignored for simplification and the contra flow is configured absolutely as 0 or 1, which ensures vehicles do not go back into the evacuation area.
Practical implications
An efficient optimization model for traffic managers to reduce congestion and evacuation time of evacuation network.
Originality/value
The new bi‐level programming model not only considers managers' character, but also considers evacuees' reaction. The paper is aimed to optimize contra flow for transportation network.
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Kun Chen, Xin Li and Huaiqing Wang
Although big data analytics has reaped great business rewards, big data system design and integration still face challenges resulting from the demanding environment, including…
Abstract
Purpose
Although big data analytics has reaped great business rewards, big data system design and integration still face challenges resulting from the demanding environment, including challenges involving variety, uncertainty, and complexity. These characteristics in big data systems demand flexible and agile integration architectures. Furthermore, a formal model is needed to support design and verification. The purpose of this paper is to resolve the two problems with a collective intelligence (CI) model.
Design/methodology/approach
In the conceptual CI framework as proposed by Schut (2010), a CI design should be comprised of a general model, which has formal form for verification and validation, and also a specific model, which is an implementable system architecture. After analyzing the requirements of system integration in big data environments, the authors apply the CI framework to resolve the integration problem. In the model instantiation, the authors use multi-agent paradigm as the specific model, and the hierarchical colored Petri Net (PN) as the general model.
Findings
First, multi-agent paradigm is a good implementation for reuse and integration of big data analytics modules in an agile and loosely coupled method. Second, the PN models provide effective simulation results in the system design period. It gives advice on business process design and workload balance control. Third, the CI framework provides an incrementally build and deployed method for system integration. It is especially suitable to the dynamic data analytics environment. These findings have both theoretical and managerial implications.
Originality/value
In this paper, the authors propose a CI framework, which includes both practical architectures and theoretical foundations, to solve the system integration problem in big data environment. It provides a new point of view to dynamically integrate large-scale modules in an organization. This paper also has practical suggestions for Chief Technical Officers, who want to employ big data technologies in their companies.
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Ruilin Guo, Qiufang Wu, Yafei Liu and Yanzhen Liu
The purpose of this paper is to attempt to solve a decision‐making problem for breeding target character showed as an interval number.
Abstract
Purpose
The purpose of this paper is to attempt to solve a decision‐making problem for breeding target character showed as an interval number.
Design/methodology/approach
A new comprehensive evaluation method was proposed based on similarity‐difference theory and interval number theory. The data from Winter Wheat Group I Variety Regional Test in Henan Province in 2009‐2010 were analysed using the proposed method.
Findings
The results showed that Zhou 99233 was a good variety, Yuxhan No.7, An 05‐28, Xun K8, Jinyumai 378 and Zhoumai 18 were better ones, 08 luo 36, and Xuke 718 ordinary ones, and others worse ones. Based on this, the feasibility of the method was discussed. It showed that the proposed method had some obvious merits, such as arithmetic was simple, operation convenient, flexible and practical, fast and effective, etc.
Practical implications
Application to a living example indicated that its evaluation effect was satisfactory. Consequently, the application prospect of the method will be very vast.
Originality/value
The paper succeeds in solving a decision‐making problem for breeding target character shown as an interval number.
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Rongwei Ren, Lei Yu and Yunxia Zhu
This paper aims to study the evolution of innovation-based dynamic capabilities in informal copycat-style firms. As a kind of informal economical organizations, copycat-style…
Abstract
Purpose
This paper aims to study the evolution of innovation-based dynamic capabilities in informal copycat-style firms. As a kind of informal economical organizations, copycat-style firms in many emerging economies play an important role in their development of the economics. The development of Shanzhai firms, Chinese-style copycat firms, from imitation to innovation has become an important micro-foundation of China’s economic growth and the manufacturing development. With the cluster development of the Chinese mobile phone industry as the macro and industrial environment background, this paper chose Beijing Tianyu Communication Equipment Co. Ltd as the typical example of innovation in Shanzhai firms and studied the evolution of innovation-based dynamic capabilities in this company.
Design/methodology/approach
This paper chose Beijing Tianyu Communication Equipment Co. Ltd as the typical example of innovation in Shanzhai firms and studied the evolution of innovation-based dynamic capabilities in this company by adopting the leading-edge dynamic capability theory, innovation theory and industrial cluster theory. The authors further discussed how to improve the dynamic capabilities in Shanzhai firms in China.
Findings
It is finally suggested that Shanzhai firms should reduce innovation failures and lower damage degree of dynamic capabilities through consistent innovation and paying attention to their innovation improvement.
Originality/value
It will be very significant to research the survival or diminishing of Shanzhai firms from a theoretical perspective, which will eventually enhance property right protection and innovation development in China.
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By introducing the basic concepts and theories of the philosophy of information created by Kun Wu, and making some comparisons of the philosophy of information and related…
Abstract
Purpose
By introducing the basic concepts and theories of the philosophy of information created by Kun Wu, and making some comparisons of the philosophy of information and related information theories between Wu and other scholars, this paper aims to have Chinese philosophy of information widely known and understood by more people in the world, thus promoting the international exchanges between Chinese and Western scholars on the topic of philosophy of information.
Design/methodology/approach
The main research methods used in this paper are the literature review and the comparative study. On the one hand, it reviews some related concepts and theories in Kun Wu's academic works of philosophy of information. On the other hand, it compares the thoughts and viewpoints of Kun Wu with those of other scholars.
Findings
First, Kun Wu is the first person who has established a complete and comprehensive theoretical system of philosophy of information in China; second, Kun Wu's philosophy of information is significant in originality and value, which could be thought as the intellectual quintessence of information age, thus worth learning. Third, with more international exchanges, Chinese philosophy of information created by Wu will surely be more and more influential in philosophical circles at home and abroad.
Originality/value
It is a very valuable first-hand material for Western scholars to know and understand Chinese philosophy of information.
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The focus of this paper is in Q-Lasso introduced in Alghamdi et al. (2013) which extended the Lasso by Tibshirani (1996). The closed convex subset Q belonging in a Euclidean m…
Abstract
The focus of this paper is in Q-Lasso introduced in Alghamdi et al. (2013) which extended the Lasso by Tibshirani (1996). The closed convex subset Q belonging in a Euclidean m-space, for
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Ming Gao, Dongkai Li, Kun Liu, Shuliang Xu, Feng Zhao, Ben Guo, Anhui Pan, Xiao Xie and Huanre Han
The brake pipe system was an essential braking component of the railway freight trains, but the existing E-type sealing rings had problems such as insufficient low-temperature…
Abstract
Purpose
The brake pipe system was an essential braking component of the railway freight trains, but the existing E-type sealing rings had problems such as insufficient low-temperature resistance, poor heat stability and short service life. To address these issues, low-phenyl silicone rubber was prepared and tested, and the finite element analysis and experimental studies on the sealing performance of its sealing rings were carried out.
Design/methodology/approach
The low-temperature resistance and thermal stability of the prepared low-phenyl silicone rubber were studied using low-temperature tensile testing, differential scanning calorimetry, dynamic thermomechanical analysis and thermogravimetric analysis. The sealing performance of the low-phenyl silicone rubber sealing ring was studied by using finite element analysis software abaqus and experiments.
Findings
The prepared low-phenyl silicone rubber sealing ring possessed excellent low-temperature resistance and thermal stability. According to the finite element analysis results, the finish of the flange sealing surface and groove outer edge should be ensured, and extrusion damage should be avoided. The sealing rings were more susceptible to damage in high compression ratio and/or low-temperature environments. When the sealing effect was ensured, a small compression ratio should be selected, and rubbers with hardness and elasticity less affected by temperature should be selected. The prepared low-phenyl silicone rubber sealing ring had zero leakage at both room temperature (RT) and −50 °C.
Originality/value
The innovation of this study is that it provides valuable data and experience for the future development of the sealing rings used in the brake pipe flange joints of the railway freight cars in China.
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Gang Wang, Wei Wang, Yi Zhang, Xu Zhang, Zhaowen Hu, Kun Liu and Daogao Wei
This paper aims to investigate the micro-plastic behavior of granular material in three-body friction interface and its effect on friction characteristics.
Abstract
Purpose
This paper aims to investigate the micro-plastic behavior of granular material in three-body friction interface and its effect on friction characteristics.
Design/methodology/approach
A numerical model of particle breakage in friction contact was constructed based on the discrete element method. The influence of friction pair working condition and internal bonding strength on the micro-plastic behavior of particulate matter was analyzed. A reciprocating linear tribometer was used to verify the simulation results.
Findings
The results show that when the granular materials are squeezed and sheared by the friction pair, a shear zone inclined to the left is gradually formed, which leads to particle breakage. The breakage of the particle leads to the reduction of load-bearing capacity and the increase of friction coefficient. Due to the differences in bond strength and friction pairs working conditions, the particle plastic behavior is divided into the following three states: elastic deformation, breakage and plastic rheology.
Originality/value
This study is helpful to understand the effect of the micro-plastic behavior of particles on the three-body friction characteristics.
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Cong Liu, Baohong Tong, Guotao Zhang, Wei Wang, Kun Liu and Peimin Xu
This paper aims to investigate the influence of oil–air lubrication flow behavior on point contact sliding wear characteristics.
Abstract
Purpose
This paper aims to investigate the influence of oil–air lubrication flow behavior on point contact sliding wear characteristics.
Design/methodology/approach
Oil–air lubrication equations between point contact counterparts were established on the basis of volume of fluid model. The effects of oil supply and injection azimuth on oil-phase volume fraction and its pressure distribution were simulated with commercial software Fluent. Characteristics of point contact sliding wear were then tested with an MFT-3000 friction tester under oil–air lubrication condition. The influence of flow behavior on wear characteristic was investigated combined with numerical and experimental results. The wear mechanism was revealed using SEM, EDS and ferrography.
Findings
When air supply speed is constant, the oil-phase volume fraction increases with the increase in oil supply, which helps form continuous oil film and decrease the sliding wear evidently. The injection angle and distance considerably influence the oil–air flow behavior. When injecting at a certain distance and angle, the oil-phase volume fraction reaches its maximum, and the abrasion loss is minimal. Under the test conditions in this study, abrasive particles are mainly debris and a few spiral cuttings. The wear mechanism is abrasive wear.
Originality/value
The influence of the behavior of oil–air lubrication flow on the characteristic of point contact sliding wear is analyzed. This work provides guidance for the application of oil–air lubrication technology in point contact friction pairs.