• 한국전산유체공학회:학술대회논문집
• /
• 2010.05a
• /
• pp.542-547
• /
• 2010

Recently, thanks to advanced computational power and numerical techniques, it is made possible to analyze the flow around moving bodies using computational fluid dynamics techniques. In those simulations, moving mesh techniques should be able to represent both the body motion and boundary deformation which are frequently encounterd in fluid-structure interaction and/of six degree-of-freedom problems. There are several moving mesh techniques such as the Laplacian operator based, tension spring based and elastic deformation based methods. In the present study, the Laplacian operator based method was utilized and the results were validated. For the validation, the flow around an oscillating two-dimensional cylinder was simulated and analyzed.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.16 no.3
• /
• pp.1063-1075
• /
• 2022

In recent years, container techniques have been broadly applied to cloud computing systems to maximize their efficiency, flexibility, and economic feasibility. Concurrently, studies have also been conducted to ensure the security of cloud computing. Among these studies, moving-target defense techniques using the high agility and flexibility of cloud-computing systems are gaining attention. Moving-target defense (MTD) is a technique that prevents various security threats in advance by proactively changing the main attributes of the protected target to confuse the attacker. However, an analysis of existing MTD techniques revealed that, although they are capable of deceiving attackers, MTD techniques have practical limitations when applied to an actual cloud-computing system. These limitations include resource wastage, management complexity caused by additional function implementation and system introduction, and a potential increase in attack complexity. Accordingly, this paper proposes a software-defined MTD system that can flexibly apply and manage existing and future MTD techniques. The proposed software-defined MTD system is designed to correctly define a valid mutation range and cycle for each moving-target technique and monitor system-resource status in a software-defined manner. Consequently, the proposed method can flexibly reflect the requirements of each MTD technique without any additional hardware by using a software-defined approach. Moreover, the increased attack complexity can be resolved by applying multiple MTD techniques.

• 한국전산유체공학회:학술대회논문집
• /
• 2011.05a
• /
• pp.68-74
• /
• 2011

Recently, thanks to the advanced computational power and numerical methods, it is made possible to analyze the flow around moving bodies using computational fluid dynamics techniques. In those simulations, moving mesh techniques should be able to represent both the body motion and boundary deformation, which are frequently encountered in fluid-structure interaction and/or six degree-of-freedom problems. In the present study, the staggered loosely coupling algorithm was used for fluid-structure interaction and the Laplacian operator based technique was used for moving mesh. For the verification of the developed computational method, the flow around a two-dimensional cylinder was simulated and analyzed.

• The Korean Journal of Emergency Medical Services
• /
• v.24 no.1
• /
• pp.77-84
• /
• 2020

Purpose: This study was conducted to determine effective chest compression methods that could be used when performing cardiopulmonary resuscitation in rocking boats. Methods: Tests were conducted for four minutes using manual and mechanical chest compressions on two mannequins, placed in boats, and moving at a speed of 35km/hours on calm sea surfaces with wave heights of 0.5m and wind speeds of 2-3m/s (testing for two minutes, followed by rest, then a second round of testing for two minutes). To compare the quality of the chest compressions, data were analyzed using mannequins (Resusci Anne Q-CPR, Laerdal, Norway) and then statistically processed. Results: When chest compressions were administered in the moving rescue boat, an accuracy analysis showed that the pressure speed of the hand and mechanical techniques were normal, h owever, the pressure depth accuracies were 49.04% for manual techniques and 0% for mechanical techniques. The relaxation accuracies during compressions were 2.07% for manual techniques and 95.4% for mechanical techniques. Conclusion: When administering chest compressions in rocking rescue boats, mechanical rather than manual techniques should be preferentially considered.

• Journal of the Korea Society of Computer and Information
• /
• v.11 no.1 s.39
• /
• pp.87-96
• /
• 2006

Selectivity estimation is one of the query optimization techniques. It is difficult for the previous selectivity estimation techniques for moving objects to apply the position change of moving objects to synopsis. Therefore, they result in much error when estimating selectivity for queries, because they are based on the extended spatial synopsis which does not consider the property of the moving objects. In order to reduce the estimation error, the existing techniques should often rebuild the synopsis. Consequently problem occurs, that is, the whole database should be read frequently. In this paper, we proposed a moving object histogram method based on quad tree to develop a selectivity estimation technique for moving object queries. We then analyzed the performance of the proposed method through the implementation and evaluation of the proposed method. Our method can be used in various location management systems such as vehicle location tracking systems, location based services, telematics services, emergency rescue service, etc in which the location information of moving objects changes over time.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 1998.06b
• /
• pp.35-40
• /
• 1998

This paper describes an automatic recognition method of contents in moving images. The recognition process is carried out by the following two steps. At first, camera works in moving images are analyzed and moving objects are extracted from the moving images. Next, the motion of the object is recognized by pre-procured knowledge. These techniques will be applied to a construction of an efficient image database.

• Structural Engineering and Mechanics
• /
• v.58 no.6
• /
• pp.1087-1107
• /
• 2016

A method of damage detection based on the moving harmonic excitation and continuous wavelet transforms is presented. The applied excitation is used as a moving actuator and its frequency and speed parameters can be adjusted for an amplified response. The continuous wavelet transforms, CWT, is used for cracks detection based on the resulting amplified signal. It is demonstrated that this identification procedure is largely better than the classical ones based on eigenfrequencies or on the eigenmodes wavelet transformed. For vibration responses, free and forced vibration analyses of multi-cracked beams are investigated based on both analytical and numerical methodological approaches. Cracks are modeled through rotational springs whose compliances are evaluated using linear elastic fracture mechanics. Based on the obtained forced responses, multi-cracks positions are accurately identified and the CWT identification can be highly improved by adjusting the frequency and the speed excitation parameters.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.118.5-118
• /
• 2001

This paper describes an image processing method for inspecting the surface outlook of high speed moving plates. Noise free image and a new real time processing methods are required to inspect the surface outlook of the high speed moving plates in real time. It is difficult to get a noise free image due to a signal noise, a light noise and background image in typical industrial factory. Thus, pre-processing techniques should be required to get a good image and produce so many time steps to proceed the image data. The objective of this research is to get image on the surface of the moving plates with a speed of 1m/sec and to detect some defaults on the surface image. So, the pre-processing techniques ...

• Proceedings of the KSR Conference
• /
• 2010.06a
• /
• pp.1492-1499
• /
• 2010

This paper is intended as an development of moving load simulation techniques. The concern with dynamic problem of railway bridge caused by the moving train loads has been growing. Over the past few years, several studies have been made on dynamic stability of railway bridge analytically. But very few attempts have been made at experimental research. From the dynamic stability view point, the moving train loads simulation test is revolutionary idea. It can be replace restrictive filed test with new laboratory test. This study investigates minimum specifications of hardware and basic parameters. it is used 39m girder and 4 actuators for experimental verification.

• Convergence Security Journal
• /
• v.8 no.4
• /
• pp.97-104
• /
• 2008

Recently, the wireless positioning techniques and mobile computing techniques have rapidly developed to use location data of moving objects. The more the number of moving objects is numerous and the more periodical sampling of locations is frequent, the more location data of moving objects become very large. Hence the system should be able to efficiently manage mass location data, support various spatio-temporal queries for LBS, and solve the uncertainty problem of moving objects. Therefore, in this paper, innovating the location data of moving object effectively, we propose Rend 3DR-tree method to decrease the dead space and complement the overlapping of nodes by utilizing 3DR-tree with the indexing structure to support indexing of current data and history data.