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1 – 10 of over 286000He Du, Ming Yang, Songyan Wang and Tao Chao
This paper aims to investigate a novel impact time control guidance (ITCG) law based on the sliding mode control (SMC) for a nonmaneuvering target using the predicted interception…
Abstract
Purpose
This paper aims to investigate a novel impact time control guidance (ITCG) law based on the sliding mode control (SMC) for a nonmaneuvering target using the predicted interception point (PIP).
Design/methodology/approach
To intercept the target with the minimal miss distance and desired impact time, an estimation of time-to-go is introduced. This estimation results in a precise impact time for multimissiles salvo attack the target at the same time. Even for a large lead angle, the desired impact time is achieved by using the sliding mode and Lyapunov stability theory. The singularity issue of the proposed impact time guidance laws is also analyzed to achieve an arbitrary lead angle with the desired impact time.
Findings
Numerical scenarios with desired impact time are presented to illustrate the performance of the proposed ITCG law. Comparison with the state-of-art impact time guidance laws proves that the guidance law in this paper can enable the missile to intercept the target with minimal miss distance and final impact time error. This method enables multiple missiles to attack the target simultaneously with different distances and arbitrary lead angles.
Originality/value
An ITCG law based on sliding mode and Lyapunov stability theory is proposed, and the switching surface is designed based on a novel estimation time-to-go for the missile to intercept the target with minimal miss distance. To intercept the target with initial arbitrary lead angles and desired impact time, the authors analysis the singular issue in SMC to ensure that the missile can intercept the target with arbitrary lead angle. The proposed approach for a nonmaneuvering target using the PIP has simple forms, and therefore, they have the superiority of being implemented easily.
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Jian Hu, Naigang Cui, Yuliang Bai and Yunhai Geng
The purpose of this paper is to present a novel guidance law that is able to control the impact time while the seeker’s field of view (FOV) is constrained.
Abstract
Purpose
The purpose of this paper is to present a novel guidance law that is able to control the impact time while the seeker’s field of view (FOV) is constrained.
Design/methodology/approach
The new guidance law is derived from the framework of Lyapunov stability theory to ensure interception at the desired impact time. A time-varying guidance gain scheme is proposed based on the analysis of the convergence time of impact time error, where finite-time stability theory is used. The circular trajectory assumption is adopted for the derivation of accurate analytical estimation of time-to-go. The seeker’s FOV constraint, along with missile acceleration constraint, is considered during guidance law design, and a switching strategy to satisfy it is designed.
Findings
The proposed guidance law can drive missile to intercept stationary target at the desired impact time, as well as satisfies seeker’s FOV and missile acceleration constraints during engagement. Simulation results show that the proposed guidance law could provide robustness against different engagement scenarios and autopilot lag.
Practical implications
The presented guidance law lays a foundation for using cooperative strategies, such as simultaneous attack.
Originality/value
This paper presents further study on the impact time control problem considering the seeker’s FOV constraint, which conforms better to reality.
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David Brennan and M. Elizabeth Davidson
While the important role of information literacy instruction as a central service in academic libraries is well observed in scholarly literature, there has been little examination…
Abstract
While the important role of information literacy instruction as a central service in academic libraries is well observed in scholarly literature, there has been little examination of the impact of the rapid increase of instructional duties on practicing librarians, whose traditional instruction duties have expanded or whose positions have not traditionally required leading a classroom. The study in this chapter explores librarians’ perceptions of the impact that increased instruction tasks have had on their day-to-day and long-term goals, perceptions of the support they receive in performing their instructional duties, and what types of instruction training they have received throughout their career. The ways in which the addition of instruction duties for librarians have been perceived by the librarians themselves as they strive to increase support for instructional services without impacting the library’s ability to continue to perform traditional public and technical services functions is discussed as a marker of the future needs of the field and the necessity of recognizing professional strain.
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Xiaolin Sun, Jiawen Zhu, Huigang Liang, Yajiong Xue and Bo Yao
As after-hours technology-mediated work (ATW) becomes common in organizations, the increased workload and interference to life caused by ATW has induced employee turnover. This…
Abstract
Purpose
As after-hours technology-mediated work (ATW) becomes common in organizations, the increased workload and interference to life caused by ATW has induced employee turnover. This research develops a mediated moderation model to explain how employees' intrinsic and extrinsic motivations for ATW affect their turnover intention through work–life conflict.
Design/methodology/approach
A survey was conducted to collect data of 484 employees from Chinese companies. Partial Least Square was used to perform data analysis.
Findings
The results show that intrinsic motivation for ATW has an indirect negative impact on turnover intention via work–life conflict, whereas extrinsic motivation for ATW has both a positive direct impact and a positive indirect impact (via work–life conflict) on turnover intention. This study also helps find that time spent on ATW can strengthen the positive impact of extrinsic motivation for ATW on turnover intention but has no moderation effect on the impact of intrinsic motivation for ATW. Furthermore, this study reveals that the interaction effect of time spent on ATW and extrinsic motivation on turnover intention is mediated by employees' perceived work–life conflict.
Originality/value
By discovering the distinct impact of employees' intrinsic and extrinsic motivations for ATW on turnover intention, this research provides a contingent view regarding the impact of ATW and offers guidance to managers regarding how to mitigate ATW-induced turnover intention through fostering different motivations.
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Huimin Jing and Yixin Zhu
This paper aims to explore the impact of cycle superposition on bank liquidity risk under different levels of financial openness so that banks can better manage their liquidity…
Abstract
Purpose
This paper aims to explore the impact of cycle superposition on bank liquidity risk under different levels of financial openness so that banks can better manage their liquidity risk. Meanwhile, it can also provide some ideas for banks in other emerging economies to better cope with the shocks of the global financial cycle.
Design/methodology/approach
Employing the monthly data of 16 commercial banks in China from 2005 to 2021 and based on the time-varying parameter vector autoregressive model with stochastic volatility (TVP-SV-VAR) model, the authors first examine whether the cycle superposition can magnify the impact of China's financial cycle on bank liquidity risk. Subsequently, the authors investigate the impact of different levels of financial openness on cycle superposition amplification. Finally, the shock of the financial cycle of the world's major economies on the liquidity risk of Chinese banks is also empirically analyzed.
Findings
Cycle superposition can magnify the impact of China's financial cycle on bank liquidity risk. However, there are significant differences under different levels of financial openness. Compared with low financial openness, in the period of high financial openness, the magnifying effect of cycle superposition is strengthened in the short term but obviously weakened in the long run. In addition, the authors' findings also demonstrate that although the United States is the main shock country, the influence of other developed economies, such as Japan and Eurozone countries, cannot be ignored.
Originality/value
Firstly, the cycle superposition index is constructed. Secondly, the authors supplement the literature by providing evidence that the association between cycle superposition and bank liquidity risk also depends on financial openness. Finally, the dominant countries of the global financial cycle have been rejudged.
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The purpose of this study is to examine the impact of interest rates on the size and the maturity choice of a syndicated bank loan. In addition, it attempts to determine the…
Abstract
Purpose
The purpose of this study is to examine the impact of interest rates on the size and the maturity choice of a syndicated bank loan. In addition, it attempts to determine the long‐run impact of a syndicated loan on the borrower's capital structure.
Design/methodology/approach
The paper uses a sample of 6,903 syndicated bank loans in the USA, covering the period 1984‐2004. First, all syndicated loans are categorized into two groups: loans in periods of increasing interest rates, and loans in periods of decreasing rates. Then, non‐parametric tests are performed to compare the characteristics of the two groups, including the proceeds from the loans, and robust regressions are used to examine the impact of the interest rates on the maturity choice. Finally, robust regressions are employed to examine the long‐run impact of the interest rates on the borrowers' leverage ratios.
Findings
On the whole, the results reject the market timing theory of capital structure for syndicated bank loans. Firms in the two groups borrow in similar amounts, and in the long run, the difference between the two groups' leverage ratios is statistically insignificant. On the other hand, firms tend to choose longer maturities when the interest rates are low compared to the rates two or three years ago.
Originality/value
To the best of the author's knowledge, this is the first study that links debt market conditions to the leverage ratios of firms that borrow in the syndicated bank loan market. In other words, this is the first study that tests the market timing theory of capital structure for syndicated bank loans.
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A.A. (Alex) Alblas and J.C. (Hans) Wortmann
In new product development (NPD), changes to the initial designs are often proposed for on‐going design projects due to new insights. These engineering changes belong to a wide…
Abstract
Purpose
In new product development (NPD), changes to the initial designs are often proposed for on‐going design projects due to new insights. These engineering changes belong to a wide range from incremental to radical and, in their impact, even to discontinuous change. Consequently, the actual workload of development projects confronted with engineering changes does not match the initial work estimates for the project's work packages. Accordingly, the intended timing of readiness of development projects in an NPD program will drift away. This timing is one of the causes of change propagation to other projects which results in even more engineering changes. For larger changes, the effects on timing may be disastrous. The purpose of this paper is to reveal the cause‐and‐effect relationships triggered by various types of changes and explain the need for a more integrated approach to managing engineering change.
Design/methodology/approach
A longitudinal case study was performed at a leading microlithography manufacturing company, in which almost 20,000 engineering changes were included. This study allowed the disclosure of the complexities of engineering change management and provides guidelines for handling the resulting problems arising from managing these various types of change.
Findings
In the study, various sources of complexities in managing engineering change were observed, which hinder effective implementation of various types of engineering change. Based on the case observations, a number of improvement possibilities are proposed, such as: alignment of goals and impacts of engineering change on all organizational levels; and planning, monitoring and controlling discontinuous engineering changes as separate projects.
Originality/value
Although further studies are needed to replicate the results, the paper gives a more thorough understanding of factors that could support the implementation of discontinuous innovation in incumbent firms by using the engineering change management process.
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Nicola J. Beatson, Paul de Lange and Heinrich Oosthuizen
Students have a finite amount of time that they can allocate between commitments of study–work–life. Striking a balance between these competing activities is an individual…
Abstract
Purpose
Students have a finite amount of time that they can allocate between commitments of study–work–life. Striking a balance between these competing activities is an individual conundrum and this study aims to explore the impact of extramural activities and paid employment on the academic performance of accounting students.
Design/methodology/approach
Guided by Carroll’s model of school learning, the authors adopt a quantitative approach where they survey (N = 264) and gather responses (n = 195) from students with respect to their choices regarding spare time outside study. These perceptions are then compared to their academic performance. Quantitative responses were subsequently triangulated with interview findings to provide in-depth analysis.
Findings
Findings provide greater understanding for educators of the student lived experience, which reveals that the work, study and life balance is individually nuanced and is largely driven by the individual’s perceived level of interference from work, which is a significant predictor of academic performance.
Originality/value
Analysis of the determinants of student learning includes prior academic achievement, confidence with numbers, critical thinking, gender and prior accounting knowledge. Yet, little is known about the implication of activities outside the formal curriculum. This study addresses this void in the literature and provides a much-needed link back to accounting faculty’s pedagogical approaches as they adapt to a cohort’s learning behaviour. This study also adds to the debate on the need for more discussion with faculty to allow alternate arrangements based on extramural activities and employment commitments. Greater understanding of study–work–life balance for students provides an opportunity for new dialog between faculty and students.
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The objective of this chapter is to identify the key characteristics of Global Services businesses that will thrive and achieve success in the future. These factors are integrated…
Abstract
The objective of this chapter is to identify the key characteristics of Global Services businesses that will thrive and achieve success in the future. These factors are integrated into three main pillars, which we refer to as the Triple-Win. The first and most obvious pillar is technology as a tool. The second pillar is the design and sustainability of the business model, without which the previous factor would be merely a cost and not an investment. And last but not the least, there is the purpose which gives meaning to the proposal, focusing on the human being and their environment. The DIDPAGA business model sits at the intersection of these three elements.
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