• 한국전문물리치료학회지
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• 제12권1호
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• pp.71-79
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• 2005

The purpose of this study was to analyze the presence of ipsilesional movement deficit, with segmental performance in each proximal or distal upper extremity. The visuoperceptual complex task of the ipsilesional upper extremity was investigated in patients with unilateral brain damage and a control group of healthy sex-age-matched controls. Tracking movements were tested in the proximal and distal upper extremities. Movements were measured by the accuracy index, which was normalized to each subject's own range of motion and took into account any differences between subjects in the excursion of the tracking target. The findings revealed that stroke patients experienced difficulties with tracking movement of both proximal and distal segments in the upper extremities on the so-called "non-affected side", irrespectively of the extent of patient's age, time since onset, or severity of contralateral upper extremity. Therefore, the unilateral brain damage affected ipsilateral motor function of the proximal and distal upper limbs in the performance of complex motor tasks, requiring central processing and the higher order cognitive function in the integrity of both hemispheres.

• Smart Structures and Systems
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• 제4권6호
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• pp.795-807
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• 2008

A challenging problem in structural damage detection based on vibration data is the requirement of a large number of sensors and the numerical difficulty in obtaining reasonably accurate results when the system is large. To address this issue, the substructure identification approach may be used. Due to practical limitations, the response data are not available at all degrees of freedom of the structure and the external excitations may not be measured (or available). In this paper, an adaptive damage tracking technique, referred to as the sequential nonlinear least-square estimation with unknown inputs and unknown outputs (SNLSE-UI-UO) and the sub-structure approach are used to identify damages at critical locations (hot spots) of the complex structure. In our approach, only a limited number of response data are needed and the external excitations may not be measured, thus significantly reducing the number of sensors required and the corresponding computational efforts. The accuracy of the proposed approach is illustrated using a long-span truss with finite-element formulation and an 8-story nonlinear base-isolated building. Simulation results demonstrate that the proposed approach is capable of tracking the local structural damages without the global information of the entire structure, and it is suitable for local structural health monitoring.

• Smart Structures and Systems
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• 제6권9호
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• pp.1057-1077
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• 2010

An early detection of structural damages is critical for the decision making of repair and replacement maintenance in order to guarantee a specified structural reliability. Consequently, the structural damage detection, based on vibration data measured from the structural health monitoring (SHM) system, has received considerable attention recently. The traditional time-domain analysis techniques, such as the least square estimation (LSE) method and the extended Kalman filter (EKF) approach, require that all the external excitations (inputs) be available, which may not be the case for some SHM systems. Recently, these two approaches have been extended to cover the general case where some of the external excitations (inputs) are not measured, referred to as the adaptive LSE with unknown inputs (ALSE-UI) and the adaptive EKF with unknown inputs (AEKF-UI). Also, new analysis methods, referred to as the adaptive sequential non-linear least-square estimation with unknown inputs and unknown outputs (ASNLSE-UI-UO) and the adaptive quadratic sum-squares error with unknown inputs (AQSSE-UI), have been proposed for the damage tracking of structures when some of the acceleration responses are not measured and the external excitations are not available. In this paper, these newly proposed analysis methods will be compared in terms of accuracy, convergence and efficiency, for damage identification of structures based on experimental data obtained through a series of laboratory tests using a scaled 3-story building model with white noise excitations. The capability of the ALSE-UI, AEKF-UI, ASNLSE-UI-UO and AQSSE-UI approaches in tracking the structural damages will be demonstrated and compared.

• Steel and Composite Structures
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• 제42권2호
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• pp.151-159
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• 2022

This study discusses a hypothetical method for tracking the propagation damage of Carbon Reinforced Fiber Plastic (CRFP) components underneath vibration fatigue. The High Cycle Fatigue (HCF) behavior of composite materials was generally not as severe as this of admixture alloys. Each fissure initiation in metal alloys may quickly lead to the opposite. The HCF behavior of composite materials is usually an extended state of continuous degradation between resin and fibers. The increase is that any layer-to-layer contact conditions during delamination opening will cause a dynamic complex response, which may be non-linear and dependent on temperature. Usually resulted from major deformations, it could be properly surveyed by a non-contact investigation system. Here, this article discusses the scanning laser application of that vibrometer to track the propagation damage of CRFP components underneath fatigue vibration loading. Thus, the study purpose is to demonstrate that the investigation method can implement systematically a series of hypothetical means and dynamic characteristics. The application of the relaxation method based on numerical simulation in the Artificial Intelligence (AI) Evolved Bat (EB) strategy to reduce the dynamic response is proved by numerical simulation. Thermal imaging cameras are also measurement parts of the chain and provide information in qualitative about the temperature location of the evolution and hot spots of damage.

• 한국화재소방학회논문지
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• 제23권2호
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• pp.62-66
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• 2009

본 연구는 국내에서 사용되고 있는 누전차단기 외함 절연재료의 소손 특성에 대하여 연구하였다. 시료는 3개 제조사의 누전차단기 외함 절연재료를 사용하였으며, 시료의 열분해특성, 연소특성, 트래킹 특성 등을 비교 분석하였다. 열분해특성은 TGA를 사용하였으며, 연소특성은 ISO5660(Fire Tests - Reaction to Fire, part 1)을 만족하는 Mass Loss Calorimeter(FTT 사)를 사용하였고, 트래킹 특성은 고체 절연재료의 내트래킹 및 비교트래킹 지수를 측정하는 실험인 KSC IEC 60112.의 기준에 따라 분석하였다. 연구결과 A제조사의 경우 내트래킹성이 가장 우수하였고, B제조사의 경우 내트래킹성이 가장 낮은 반면 $350^{\circ}C$ 이상의 고온에서 열안정성이 가장 우수하였으며, C제조사의 경우 $400^{\circ}C$ 이하의 온도에서 열안정성이 가장 우수한 것을 알 수 있었다.

• 중소기업융합학회논문지
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• 제4권4호
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• pp.13-18
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• 2014

스마트폰 개발의 발전으로 인하여 사용자의 스마트폰 사용율이 PC 사용율보다 점점 높아지고 있는 실정이다. 스마트폰 사용이 대중화되면서 스마트폰 사용자의 개인신상정보, 금융 정보와 같은 중요한 프라이버시 정보들을 보호하는 연구는 현재 미미한 상태이다. 본 논문에서는 현재까지 연구되었던 스마트폰의 다양한 취약점에 대해서 분석하고 스마트폰 보안 공격 방법에 대한 대응방법 및 스마트포 소비자 분쟁 해결 기준들을 제시한다. 특히, 스마트폰에서 발생하기 쉬운 보안 위협(네트워크, 악성코드, 훔쳐보기 공격 등)을 통해 사용자의 개인정보 유출이나 금전적 손실과 같은 직접적인 피해를 최소화하기 위한 방법들을 분석한다.

• 한국해양공학회지
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• 제37권4호
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• pp.158-163
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• 2023

Objects adrift can cause considerable damage to coastal infrastructure and property during tsunami and storm surge events. Despite the potential for harm, the drifting behavior of these objects remains poorly understood, thereby hindering effective prediction and mitigation of collision damage. To address this gap, this study employed a motion analysis program to track a drifting container's location using images from an existing laboratory experiment. The container's trajectory and velocity were calculated based on the positions of five markers strategically placed at its four corners and center. Our findings indicate that the container's maximum drift velocity and distance are directly influenced by the scale of the solitary wave and inversely related to the container's weight. Specifically, heavier containers are less likely to be displaced by solitary waves, while larger waves can damage coastal structures more. This study offers new insights into container drift behavior induced by solitary waves, with implications for enhancing coastal infrastructure design and devising mitigation strategies to minimize the risk of collision damage.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2320-2322
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• 1999

This paper was studied on the surface discharge characteristics and tracking phenomena on the solid insulator in liquid nitrogen ($LN_2$) at atmospheric pressure. In order to investigate the bubbles which have much influence on electric surface discharge in liquid nitrogen, Knife type electrode and plane electrode were arranged in different modes(Mode A, Mode B, and Mode C) and investigated for surface discharge and tracking phenomena. In Mode A, by the movement of bubbles tracking damage was formed under the electrodes. The tracking pattern in Mode B was formed along the electrode axis.

• 전자공학회논문지
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• 제53권9호
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• pp.137-142
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• 2016

컴퓨터단층촬영(CT) 검사의 정맥주사(IV)시 조영제의 혈관외유출은 조직손상을 유발할 수 있다. Bolus tracking 시스템을 이용하여 조영제를 주입과정에서 발생하는 혈관외유출을 검출한다. 또한 조직손상을 방지하기 위하여 MPR 및 VR 영상을 이용하여 혈관외유출을 검출하였다. 조영제의 혈관외유출을 검출하기 위하여 16MDCT, 64MDCT를 사용하였다. 혈관외유출에 대한 3차원영상은 환자치료에 중요한 치료정보를 제공할 수 있다. 또한 조영제와 조직 간의 선예도를 개선하기 위해서 edge enhancement 영상처리기법을 적용하였고, 선예도 및 대조도가 개선되었다.

• 한국안전학회지
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• 제28권2호
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• pp.21-25
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• 2013

The purpose of this study is to provide basic data for the safety assessment of a water purifier when water leaks due to inappropriate maintenance and the examination of the cause of accidents related to the leak. Due to its inspection and management by non-specialists, if a leak occurs in a water purifier with the water level controller being inclined, it may result in the failure of the compressor, power supply line, PCB, etc. The analysis of the thermal diffusion pattern of water purifier compressors using a thermal image camera shows that its maximum temperature was approximately $80^{\circ}C$. In addition, its operating current was a maximum of 13 A and the system's operating current was approximately 1.7 A after the compressor was charged. It was found that the housing type power cable cover of the compressor had the effect of preventing electric shock but has poor flame resistance. Furthermore, the performance of the overload protector, PTC relays, etc., was excellent but they have potential for problems as metallic terminals were exposed, resulting in the potential of a safety related accident. The terminals and their surface damaged by the tracking showed a trace of carbonization and the resistance between terminals was measured to be approximately $8{\Omega}$. In addition, while the tracking was proceeding, the fuse and circuit breaker installed for system protection did not operate.