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Article

Hyeong-Uk Park, Joon Chung and Ohyun Kwon

The purpose of this paper is a development of a virtual flight test framework with derivative design optimization. Aircraft manufactures and engineers have been putting…

Abstract

Purpose

The purpose of this paper is a development of a virtual flight test framework with derivative design optimization. Aircraft manufactures and engineers have been putting significant effort into the design process to lower the cost of development and time to a minimum. In terms of flight tests and aircraft certification, implementing simulation and virtual test techniques may be a sufficient method in achieving these goals. In addition to simulation and virtual test, a derivative design can be implemented to satisfy different market demands and technical changes while reducing development cost and time.

Design/methodology/approach

In this paper, a derivative design optimization was applied to Expedition 350, a small piston engine powered aircraft developed by Found Aircraft in Canada. A derivative that changes the manned aircraft to an Unmanned Aerial Vehicle for payload delivery was considered. An optimum configuration was obtained while enhancing the endurance of the UAV. The multidisciplinary design optimization module of the framework represents the optimized configuration and additional parameters for the simulator. These values were implemented in the simulator and generated the aircraft model for simulation. Two aircraft models were generated for the flight test.

Findings

The optimization process delivered the UAV derivative of Expedition E350, and it had increased endurance up to 21.7 hours. The original and optimized models were implemented into virtual flight test. The cruise performance exhibited less than 10 per cent error on cruise performance between the original model and Pilots Operating Handbook (POH). The dynamic stability of original and optimized models was tested by checking Phugoid, short period, Dutch roll and spiral roll modes. Both models exhibited stable dynamic stability characteristics.

Practical implications

The original Expedition 350 was generated to verify the accuracy of the simulation data by comparing its result with actual flight test data. The optimized model was generated to evaluate the optimization results. Ultimately, the virtual flight test framework with an aircraft derivative design was proposed in this research. The additional module for derivative design optimization was developed and its results were implemented to commercial off-the-shelf simulators.

Originality/value

This paper proposed the application of UAV derivative design optimization for the virtual flight test framework. The methodology included the optimization of UAV derivative utilizing MDO and virtual flight testing of an optimized result with a flight simulator.

Details

Aircraft Engineering and Aerospace Technology, vol. 90 no. 9
Type: Research Article
ISSN: 1748-8842

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Article

Maryam Safi, Joon Chung and Pratik Pradhan

The purpose of this paper is to assess and determine the potential of augmented reality (AR) in aerospace applications through a survey of published sources.

Abstract

Purpose

The purpose of this paper is to assess and determine the potential of augmented reality (AR) in aerospace applications through a survey of published sources.

Design/methodology/approach

This paper reviews a database of AR applications developed for the aerospace sector in academic research or industrial training and operations. The review process begins with the classification of these applications, followed by a brief discussion on the implications of AR technology in each category.

Findings

AR is abundantly applied in engineering, navigation, training and simulation. There is potential for application in in-flight entertainment and communication, crew support and airport operations monitoring.

Originality/value

This paper is a general review introducing existing and potential AR applications in various fields of the aerospace industry. Unlike previous publications, this article summarizes existing and emerging applications to familiarize readers with AR use in all of aerospace. The paper outlines example projects and creates a single comprehensive reference of AR advancements and its use in the aerospace industry. The paper provides individuals with a quick guide to available and emerging technology.

Details

Aircraft Engineering and Aerospace Technology, vol. 91 no. 9
Type: Research Article
ISSN: 1748-8842

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Abstract

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Strategic Thinking
Type: Book
ISBN: 978-1-78560-466-9

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Article

Soo-Jung Jung, Bum-Joon Kim and Ju-Ryum Chung

This paper aims to examine how the relationship between abnormal audit fees and audit quality changed after adoption of the International Financial Reporting Standards…

Abstract

Purpose

This paper aims to examine how the relationship between abnormal audit fees and audit quality changed after adoption of the International Financial Reporting Standards (IFRS) in Korea.

Design/methodology/approach

Using empirical data collected over the period from 2008 to 2013, this study analyzes the association between abnormally high/low audit fee and audit quality. This study uses linear regression to test the hypothetical relation using discretionary accrual as a proxy for audit quality.

Findings

This study finds that there exists no significant relationship between abnormally high audit fees and audit quality measured by the magnitude of discretionary accruals in the pre-IFRS adoption period. However, the relationship between abnormally high audit fees and the magnitude of discretionary accruals turns to be positive in the post-IFRS adoption period. These finding suggests that the IFRS enables some clients to engage more discretion in the choice of discretionary accruals and auditors charge higher audit fees in return for allowing the discretion for such clients.

Practical implications

This study provides insight to regulators of the need to review carefully the financial statements of firms with abnormally high audit fees, and to investors to be more cautious when using financial information about these firms.

Originality/value

To the best of authors’ knowledge, this is the first study to assess IFRS impact on audit fee-quality relation. Also, unique Korean audit market with intensifying competition and discounting audit fee provides interesting setting to review the impact of abnormal audit fee on audit quality.

Details

International Journal of Accounting and Information Management, vol. 24 no. 3
Type: Research Article
ISSN: 1834-7649

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Book part

Il Joon Chung

After the Korean War, South Korean politics was dominated by national security concerns. Reversing Carl von Clausewitz's well-known dictum, in South Korea, “politics is…

Abstract

After the Korean War, South Korean politics was dominated by national security concerns. Reversing Carl von Clausewitz's well-known dictum, in South Korea, “politics is the continuation of war by other means.” Until the late 1980s, politics in South Korea was far from democratic. South Korea had five direct presidential elections (1987, 1992, 1997, 2002, and 2007) and six national assembly elections (1988, 1992, 1996, 2000, 2004, and 2008) after the democratic transition of 1987. In 1992, a civilian candidate, Young Sam Kim, was elected president. Young Sam Kim (1993–1998) prosecuted and punished former generals turned presidents Doo Hwan Chun (1980–1988) and Tae Woo Roh (1988–1993) for corruption, mutiny and treason in 1995. Dae Jung Kim (1998–2003) was elected president in 1997. For the first time in South Korean political history, regime change occurred between a ruling party and an opposition party.

In this chapter, the change and continuity of civil–military relations through the fluctuating dynamics of the democratic transition and consolidation in South Korea is examined. A positive consolidation of democratic reform is one that, while securing indisputable civilian supremacy, grants the military enough institutional autonomy for the efficient pursuit of its mission. Civilian supremacy should be institutionalized not only by preventing military intervention in civilian politics but also by ensuring civilian control over the formation and implementation of national defense policy.

In sum, despite three terms of civilian presidency, civilian supremacy has not yet fully institutionalized. Although significant changes in civil-military relations did occur after the democratic transition, they were not initiated by elected leaders with the intention of establishing a firm institutional footing for civilian supremacy. South Korea's political leaders have not crafted durable regulations and institutions that will sustain civilian control over the military.

More than six decades, Korea is still divided. The most highly militarized zone in the world lies along the demilitarized zone. How to draw the line prudently between seeking national security and promoting democracy shall be the most delicate task facing all the civilian regimes to come in South Korea. That mission will remain challenging not only for civilian politicians but also for military leaders.

Details

Advances in Military Sociology: Essays in Honor of Charles C. Moskos
Type: Book
ISBN: 978-1-84855-893-9

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Book part

Joon-Hai Chung and Mary A. Weiss

The puzzle of underwriting cycles and insurance crises in property-liability insurance has led to numerous economic hypotheses and analyses, yet no single theory seems…

Abstract

The puzzle of underwriting cycles and insurance crises in property-liability insurance has led to numerous economic hypotheses and analyses, yet no single theory seems capable of explaining all of its aspects. Reinsurance is hypothesized to be a potential factor in observed cycles in the primary market; despite this, few underwriting cycle studies focusing on reinsurance exist. The purpose of this research is to apply two principal underwriting cycle theories: the capacity constraint and risky debt hypotheses, to non-proportional property and casualty reinsurance in the U.S. Non-proportional reinsurance is highlighted, since it is designed to cover the tail of the loss distribution and is considered to be relatively riskier than proportional reinsurance as a result. Two professional U.S. reinsurer samples are studied, one for property and one for casualty; U.S. reinsurers in each sample were chosen on the basis of their non-proportional property (casualty) writings. The sample period is 1991 to 1995. The results support both the capacity constraint hypothesis and the risky debt hypothesis, and this is the first research to do so. A major innovation in this study is the use of capacity variables that are broken down by major region of the world

Details

Global Risk Management: Financial, Operational, and Insurance Strategies
Type: Book
ISBN: 978-1-84950-189-7

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Article

Hyeong-Uk Park, Jae-Woo Lee, Joon Chung and Kamran Behdinan

The purpose of this paper is to study the consideration of uncertainty from analysis modules for aircraft conceptual design by implementing uncertainty-based design…

Abstract

Purpose

The purpose of this paper is to study the consideration of uncertainty from analysis modules for aircraft conceptual design by implementing uncertainty-based design optimization methods. Reliability-Based Design Optimization (RBDO), Possibility-Based Design Optimization (PBDO) and Robust Design Optimization (RDO) methods were developed to handle uncertainties of design optimization. The RBDO method is found suitable for uncertain parameters when sufficient information is available. On the other hand, the PBDO method is proposed when uncertain parameters have insufficient information. The RDO method can apply to both cases. The RBDO, PBDO and RDO methods were considered with the Multidisciplinary Design Optimization (MDO) method to generate conservative design results when low fidelity analysis tools are used.

Design/methodology/approach

Methods combining MDO with RBDO, PBDO and RDO were developed and have been applied to a numerical analysis and an aircraft conceptual design. This research evaluates and compares the characteristics of each method in both cases.

Findings

The RBDO result can be improved when the amount of data concerning uncertain parameters is increased. Conversely, increasing information regarding uncertain parameters does not improve the PBDO result. The PBDO provides a conservative result when less information about uncertain parameters is available.

Research limitations/implications

The formulation of RDO is more complex than other methods. If the uncertainty information is increased in aircraft conceptual design case, the accuracy of RBDO will be enhanced.

Practical implications

This research increases the probability of a feasible design when it considers the uncertainty. This result gives more practical optimization results on a conceptual design level for fabrication.

Originality/value

It is RBDO, PBDO and RDO methods combined with MDO that satisfy the target probability when the uncertainties of low fidelity analysis models are considered.

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Abstract

Details

Advances in Military Sociology: Essays in Honor of Charles C. Moskos
Type: Book
ISBN: 978-1-84855-893-9

To view the access options for this content please click here

Abstract

Details

Global Risk Management: Financial, Operational, and Insurance Strategies
Type: Book
ISBN: 978-1-84950-189-7

Content available
Book part

Abstract

Details

The Handbook of Business and Corruption
Type: Book
ISBN: 978-1-78635-445-7

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