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Article
Publication date: 20 September 2019

Yijun Hou, Dongdong Wang and Guoqi Dong

The purpose of this paper is to take the early Permian no.6 coal seam in Jungar coalfield of North China as an example, this paper studied the net primary productivity (NPP) level…

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Abstract

Purpose

The purpose of this paper is to take the early Permian no.6 coal seam in Jungar coalfield of North China as an example, this paper studied the net primary productivity (NPP) level of the early Permian peatland and its relationship with the atmospheric environment at that time, analyzed the influence of the atmospheric environment, and discussed its control factors.

Design/methodology/approach

First, geophysical logging signals were used for a spectrum analysis to obtain the Milankovitch cycle parameters in the no. 6 coal seam, including the eccentricity (95 ka); obliquity (35.6 ka); and precession (21.2 ka). These were then used to calculate the accumulation rate of the residual carbon in the no. 6 coal seam, which was determined to be between 49.44 and 50.57 gC/(m2 · a). The carbon loss could be calculated according to the density and residual carbon content of the no. 6 coal seam. Then, the total carbon accumulation rate of the peatland was further derived as being between 64.91 and 66.40 gC/(m2 · a). Also, the NPP of the peatland was determined to be between 129.82 and 132.8 gC/(m2 · a).

Finding

The result showed that the NPP of the early Permian peatland area was lower than that of the Holocene at the same latitude, and also lower than that of the later Permian of South China.

Originality/value

This study’s comprehensive analysis indicated that the temperature and humidity conditions, along with the oxygen and carbon dioxide levels in the atmosphere, were the main control factors of the NPP of the early Permian peatland. Also, wildfires were found to play a role.

Details

World Journal of Engineering, vol. 16 no. 5
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 2 October 2017

Daifeng Zhang, Haibin Duan and Yijun Yang

The purpose of this paper is to propose a control approach for small unmanned helicopters, and a novel swarm intelligence algorithm is used to optimize the parameters of the…

357

Abstract

Purpose

The purpose of this paper is to propose a control approach for small unmanned helicopters, and a novel swarm intelligence algorithm is used to optimize the parameters of the proposed controller.

Design/methodology/approach

Small unmanned helicopters have many advantages over other unmanned aerial vehicles. However, the manual operation process is difficult because the model is always instable and coupling. In this paper, a novel optimized active disturbance rejection control (ADRC) approach is presented for small unmanned helicopters. First, a linear attitude model is built in hovering condition according to small perturbation linearization. To realize decoupling, this model is divided into two parts, and each part is equipped with an ADRC controller. Finally, a novel Levy flight-based pigeon-inspired optimization (LFPIO) algorithm is developed to find the optimal ADRC parameters and enhance the performance of controller.

Findings

This paper applies ADRC method to the attitude control of small unmanned helicopters so that it can be implemented in practical flight under complex environments. Besides, a novel LFPIO algorithm is proposed to optimize the parameters of ADRC and is proved to be more efficient than other homogenous methods.

Research limitations/implications

The model of proposed controller is built in the hovering action, whereas it cannot be used in other flight modes.

Practical implications

The optimized ADRC method can be implemented in actual flight, and the proposed LFPIO algorithm can be developed in other practical optimization problems.

Originality/value

ADRC method can enhance the response and robustness of unmanned helicopters which make it valuable in actual environments. The proposed LFPIO algorithm is proved to be an effective swarm intelligence optimizer, and it is convenient and valuable to apply it in other optimized systems.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 6
Type: Research Article
ISSN: 1748-8842

Keywords

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Article
Publication date: 18 June 2021

Salamatu Bellah Conteh and Yijun Yuan

An important objective of human resource (HR) research is to understand how HR practices can influence employee attitudes and behaviors in order to help achieve organizational…

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Abstract

Purpose

An important objective of human resource (HR) research is to understand how HR practices can influence employee attitudes and behaviors in order to help achieve organizational goals via employee performance. The paper studies the relationship between High Performance Work System (HPWS) and employee service performance (ESP) via organizational support (OS) and organizational identification (OI). On one hand, this may help understand the “black box” between HPWS practices and ESP. On the other hand, while OS refers to employees' evaluations of favorable treatment from the organization and HPWS represent a significant channel the organization uses to communicate its support to employees, OS and OI literatures have not comprehensively examined the effect of HPWS practices on employee OS and OI beliefs.

Design/methodology/approach

This study takes a quantitative approach and employs hierarchical regression from a sample of 467 employees in 10 commercial banks in Sierra Leone.

Findings

The results show a positive relationship between HPWS practices and ESP and at the same time OS and OI partially mediate the relationship, suggesting that employees draw inferences from the HPWS-related treatment they receive in assessing the supportiveness of the organization.

Research limitations/implications

In this study, the authors put forth an innovative conceptual model of performance management by testing the relationships which have not been tested before, especially in a new context of banking industry in Sierra Leone. By implementing HPWS practices that demonstrate the organization cares about the employees' well-being and values their contribution, organizations are likely to be perceived as offering high levels of support for the employees.

Originality/value

The results of this study add to our knowledge about the antecedents of OS and OI. Moreover, while OS and OI research has been largely rooted in the organizational behavior literature, this study bridges the human resource literature and the organizational behavior literature, by combining HPWS, OS, OI and ESP.

Details

International Journal of Productivity and Performance Management, vol. 71 no. 7
Type: Research Article
ISSN: 1741-0401

Keywords

Available. Open Access. Open Access
Article
Publication date: 5 May 2021

Sulaimon Olanrewaju Adebiyi, Oludayo Olatosimi Ogunbiyi and Bilqis Bolanle Amole

The purpose of this paper is to implement a genetic algorithmic geared toward building an optimized investment portfolio exploring data set from stocks of firms listed on the…

4491

Abstract

Purpose

The purpose of this paper is to implement a genetic algorithmic geared toward building an optimized investment portfolio exploring data set from stocks of firms listed on the Nigerian exchange market. To provide a research-driven guide toward portfolio business assessment and implementation for optimal risk-return.

Design/methodology/approach

The approach was to formulate the portfolio selection problem as a mathematical programming problem to optimize returns of portfolio; calculated by a Sharpe ratio. A genetic algorithm (GA) is then applied to solve the formulated model. The GA lead to an optimized portfolio, suggesting an effective asset allocation to achieve the optimized returns.

Findings

The approach enables an investor to take a calculated risk in selecting and investing in an investment portfolio best minimizes the risks and maximizes returns. The investor can make a sound investment decision based on expected returns suggested from the optimal portfolio.

Research limitations/implications

The data used for the GA model building and implementation GA was limited to stock market prices. Thus, portfolio investment that which to combines another capital market instrument was used.

Practical implications

Investment managers can implement this GA method to solve the usual bottleneck in selecting or determining which stock to advise potential investors to invest in, and also advise on which capital sharing ratio to reduce risk and attain optimal portfolio-mix targeted at achieving an optimal return on investment.

Originality/value

The value proposition of this paper is due to its exhaustiveness in considering the very important measures in the selection of an optimal portfolio such as risk, liquidity ratio, returns, diversification and asset allocation.

Details

Rajagiri Management Journal, vol. 16 no. 1
Type: Research Article
ISSN: 0972-9968

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Article
Publication date: 19 November 2024

Abdul Jelil Abukari, Wenyuan Li, Abdul Rasheed Akeji Alhassan Alolo, Pomegbe Wisdom Wise Kwabla, Ingrid Ruth Epezagne Assamala and Ibrahim Sulemana

The study constructs a novel theoretical model based on resource orchestration theory and examines it using data from Ghanaian small and medium-sized enterprises (SMEs).

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Abstract

Purpose

The study constructs a novel theoretical model based on resource orchestration theory and examines it using data from Ghanaian small and medium-sized enterprises (SMEs).

Design/methodology/approach

Entrepreneurial bricolage (EB) represents a creative mechanism by which SMEs navigate resource challenges to become competitive. The purpose of this paper is to examine the link between EB to both innovation performance and firm performance among manufacturing SMEs in Ghana. In addition, we also examine the mediating role of polychronicity in the relationship between EB, innovation performance and firm performance.

Findings

The results suggest that EB positively and significantly influences both innovation performance and firm performance. Furthermore, polychronicity partially mediates the relationship between EB and innovation performance and between EB and firm performance.

Originality/value

This study enhances our understanding of the conditions under which EB may facilitate the attainment of innovation and firm performance among manufacturing SMEs. These findings also proffer practical and managerial implications for managing SMEs under resource constraints.

Details

Cross Cultural & Strategic Management, vol. 31 no. 4
Type: Research Article
ISSN: 2059-5794

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Article
Publication date: 3 September 2024

Sunil Kumar and Dushyanth Kumar

The power sector organizations are transforming swiftly with technological advancements and competition in the market. The present study aims to validate the determinants of…

62

Abstract

Purpose

The power sector organizations are transforming swiftly with technological advancements and competition in the market. The present study aims to validate the determinants of employee resilience in hydropower organizations.

Design/methodology/approach

A quantitative, cross-sectional research approach was used to conduct the study. The information was collected through a structured questionnaire from 853 employees working in 30 hydropower plants in North India. The PLS-SEM technique used to validate the extracted factors' structure.

Findings

The study validated determinants of employee resilience: self-management, flexibility and proactiveness, interactive, vision, relationships and problem-solving skills.

Research limitations/implications

The implications of employee resilience as a strategic tool to diffuse rapid work and environmental changes is validated in select hydropower plants.

Originality/value

The research is original and conducted in the hydropower sector to explore the concept of employee resilience.

Details

Continuity & Resilience Review, vol. 6 no. 2
Type: Research Article
ISSN: 2516-7502

Keywords

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