• Structural Engineering and Mechanics
• /
• v.81 no.5
• /
• pp.647-664
• /
• 2022

The powerful data mapping capability of computational deep learning methods has been recently explored in academic works to develop strategies for structural health monitoring through appropriate characterization of dynamic responses. In many cases, these studies concern laboratory prototypes and finite element models to validate the proposed methodologies. Therefore, the present work aims to investigate the capability of a deep learning algorithm called Sparse Autoencoder (SAE) specifically focused on detecting structural alterations in real-case studies. The idea is to characterize the dynamic responses via SAE models and, subsequently, to detect the onset of abnormal behavior through the Shewhart T control chart, calculated with SAE extracted features. The anomaly detection approach is exemplified using data from the Z24 bridge, a classical benchmark, and data from the continuous monitoring of the San Vittore bell-tower, Italy. In both cases, the influence of temperature is also evaluated. The proposed approach achieved good performance, detecting structural changes even under temperature variations.

• Transactions of the KSME C: Technology and Education
• /
• v.3 no.2
• /
• pp.125-130
• /
• 2015

Using flexible multibody system dynamic method, the rigid-flexible coupling multibody dynamic analysis model of the drum brake system was developed, and the kinematic and dynamic simulation of the system was processed as its object of study. Simulations show that the friction will increase with the dynamic friction coefficient, but high dynamic friction coefficient will cause the abnormal vibration and worsen the stability of the brake system, even the stability of the whole automobile. The modeling of flexible multi-body can effectively analyze and solve complex three-dimensional dynamic subjects of brake system and evaluate brake capability. Further research and study on this basis will result in a convenient and effective solution that can be much helpful to study, design and development of the brake system.

• Journal of the Ergonomics Society of Korea
• /
• v.12 no.2
• /
• pp.85-91
• /
• 1993

Data obtained for sensory evaluation have a wide dispersion and fuzziness since human sensory organs are used as a means of measuring sensation instead of measuring instruments. Such dispersion and fuzziness are caused by all kinds of time error and have a great influence on the sensory evaluation, but most of previous papers not consider time errors. In this study, the comparative judgement capability of the evaluator was discriminated by means of the eigen- structure analysis on the premise that evaluation values of sensory evaluators obtained by a paired-comparison become different by the order of sample presentation.

• Journal of Technology Innovation
• /
• v.8 no.2
• /
• pp.171-202
• /
• 2000

This study presents a developmental pattern of technological capability of catching-up players in terms of production, investment, innovation and networking capability. In order to do this, the study develops an analytical framework and examines the experience of the Korean semiconductor industry. Although the presented pattern in the study is not a general pattern for all catching-up players, this pattern implies one of the useful dynamic strategies for catching-up players in developing countries. In addition, this study discusses its contributions and further research areas in the last part of the paper.

• Proceedings of the KIEE Conference
• /
• 2002.07d
• /
• pp.2143-2145
• /
• 2002

This paper proposes the control problem of an inverted pendulum system based on adaptive fuzzy sliding mode. The universal approximating capability, learning ability, adaptation capability and disturbance rejection are collected in one control strategy. The proposed scheme does not require an accurate dynamic model and the joint acceleration measurement, yet it guarantees asymptotic trajectory tracking. Experimental results perform with an inverted pendulum to show the effectiveness of the approach.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2004.11a
• /
• pp.1005-1011
• /
• 2004

Squeeze film dampers (SFDs) have been commonly used to effectively enhance the dynamic behavior of the rotating shaft supported by rolling element bearings. However, due to the recent trends of high operating speed, high load capacity and light weight in rotating machinery, it is becoming increasingly important to change the dynamic characteristics of rotating machines in operation so that the excessive vibrations, which may occur particularly when passing through critical speeds or unstable regions, can be avoided. Semi-active type SFDs using magneto-rheological fluid (MR fluid), which responds to an applied magnetic field with a change in rheoloaical behavior, are introduced in order to find its applications to rotating machinery as an effective device attenuating unbalance responses. In this paper, a semi-active SFD using MR fluid is designed, tested and identified by means of linear analysis to investigate the capability of changing its dynamic properties such as damping and stiffness. Furthermore, the proposed device is applied to a rotor system to investigate its potential capability for vibration attenuation: an efficient method for selecting the optimal location of the proposed damper is introduced and control algorithm that could improve the unbalance response properties of a flexible rotor is also proposed.

• Journal of Navigation and Port Research
• /
• v.46 no.5
• /
• pp.435-440
• /
• 2022

The development and introduction of a Maritime Autonomous Surface Ship (MASS) are some of the most important changes leading to the fourth industrial era in the maritime area. The term 'MASS' refers to a ship operating independently, without human intervention, to reduce maritime accidents caused by human errors. Recent UK findings MASS also noted that particularly the dynamic positioning system will be considered to apply as newly function to a MASS. The DP system, a ship system developed decades ago and used for specific purposes like offshore operations, provides various functions to facilitate the accurate movements of the vessel, and operators can make decisions within the DP system, in addition to the ordinary ship system. In this paper, it would like to present the connection and application method with the main technical elements of the DP system in connection with the main technology of the DP system to achieve the safe operation of a MASS. In particular, among various position reference systems, the capability plot function of DP system, and the "follow target" mode in the operation mode are attractive functions that can contribute to the safe operation of autonomous ships.

• Industry Promotion Research
• /
• v.9 no.2
• /
• pp.207-221
• /
• 2024

Automotive manufacturing is a traditional manufacturing industry that consumes a lot of energy and emits a lot of pollutants, and needs to improve environmental performance through digital transformation of supply chains.In this study, 13 hypotheses were put forward based on supply chain digital transformation, supply chain dynamic capability and enterprise environmental performance. The results of the questionnaire survey on the managers and employees of automobile manufacturing enterprises in 7 regions of China show that the digital transformation of supply chain can help improve the environmental performance of automobile manufacturing enterprises under the influence of supply chain dynamic capability

• Transactions of the Korean hydrogen and new energy society
• /
• v.15 no.3
• /
• pp.175-186
• /
• 2004

In this paper, we developed the dynamic model of a fuel cell system suitable for controller design and system operation. The transient phenomena captured in the model include the flow characteristics and inertia dynamics of the compressor, the intake manifold filling dynamics, oxygen partial pressures and membrane humidity on the fuel cell voltage. In the simulations, we paid attention to the transient behavior of stack voltage and compressor pressure, stoichiometric ratio. Simulation results are presented to demonstrate the model capability. For load current following, stack voltage dynamic characteristics are plotted to understand the Electro-chemistry involved with the fuel cell system. Compressor pressure and stoichiometric ratio are strongly coupled, and independent parameters may interfere with each other, dynamic response, undershoot and overshoot.

• The Journal of Society for e-Business Studies
• /
• v.17 no.1
• /
• pp.189-214
• /
• 2012

In recent years, the innovative management tool of Business Process Management (BPM), has begun to reorganize business processes to enhance firms' operational performance. As practitioners have identified a number of failed BPM projects, research has begun to consider the Critical Success Factors (CSFs) for successful BPM implementation. However, these research works have not yet been properly theoretically grounded in being able rigorously to classify and then compare different BPM implementation practices. The main objective of this paper is thus to identify a theoretical basis for BPM implementation. The paper proposes a combined theoretical framework of dynamic capability and task-technology fit to identify CSFs for BPM. This basis is then used to interpret three different case studies of BPM implementation in Korea.