• 한국전기전자재료학회논문지
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• 제11권11호
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• pp.1035-1042
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• 1998

After the 1990's, a computer-aided partial discharge(PD) measurement system was referred in part of aging diagnosis using digital signal processing as the new technology has been studied. The PD patterns and relevant information for pattern recognition are discussed in PD research area, because discharge quantity(q), the number of discharge pulse(n) and the applied boltage phase($\varphi$) was combined with the system information of the aging state. This paper investigates the discharge phase and quantity, as well as the number of discharge(n) with regard to discharge signals generated in power cable. therefore, according to characteristic analysis on the distribution of $\varphi$, q and n, it is able to apply in the aging analysis of power cable which visual observation is impossible and distribution change of discharge signals offers much information for risk degree on aging progress of insulation materials.

• 한국전문물리치료학회지
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• 제11권4호
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• pp.1-6
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• 2004

The kinematics involved in different landing strategies may be related to the occurrence of trauma. Several sources suggest that the angle of knee extension on touchdown and impact with the ground determines the magnitude of the impact force and, indirectly, knee loading. This study compared the initial knee angle and maximum knee flexion angle at the instant of impact on drop-landings between healthy men and women. In this study, 60 participants (30 males, 30 females) dropped from a height of 43 cm. A digital camera and video motion analysis software were used to analyze the kinematic data. When landing, there was significant difference between the two groups ($15.67{\pm}6.05^{\circ}$ in male, $24.10{\pm}6.34^{\circ}$ in female) in the mean knee flexion angle. The range of knee flexion on landing ($44.06{\pm}10.97^{\circ}$ in male, $36.96{\pm}9.99^{\circ}$ in female) also differed significantly (p<.05). The greater knee flexion that was observed in the male subjects would be expected to decrease their risk of injury. Women land with smaller range of knee flexion than men and this might increase the likelihood of a knee injury.

• 경영정보학연구
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• 제8권1호
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• pp.223-239
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• 2006

디지털 경제 시대에 있어 정보시스템은 기업의 경쟁 우위 확보 차원을 넘어 생존의 차원에서 필요성을 인정 받고 있다. 기업은 신규 개발 또는 ERP 도입을 통해 정보시스템을 개발하고 이를 기반으로 사업을 추진하고 확장해야 하는 것이다. 그러나, 이러한 정보시스템의 성공적 운영에는 많은 현실적 문제가 있음을 인식해야 할 것이다. 특히, 중소기업의 경우 정보 시스템 운영 단계에서 많은 문제가 노출되어 운영에 차질이 생기거나 운영 자체를 포기하는 사례가 발생하고 있다. 본 논문은 중소기업의 성공적인 정보화 지속을 위해 효과적인 정보시스템 유지보수와 진화 관리를 위한 프레임웍을 제시하고자 한다. 사례 연구를 통해 설계된 프레임웍은 서비스 프레임웍, 감사 프레임웍, 위험관리 프레임웍 등으로 구성되어 있으며 중소기업의 정보화를 지속적으로 구현할 수 있는 정보시스템의 효과적인 운영 체제 구축에 활용될 수 있을 것으로 기대된다.

• 한국멀티미디어학회논문지
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• 제23권11호
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• pp.1372-1382
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• 2020

This paper proposes a core technology for a micro river monitoring terminal device suitable for flood monitoring in small rivers and valleys. Our proposed device is basically equipped with a 77GHz radar, gyro and accelerometer sensors. To measure the flow velocity and water level, we proposed a signal processing technique that extracts pure water energy components from the observed Doppler velocity and reflection intensity from the radar. And to determine the stability of the river structure equipped with our device, we constantly monitor the displacement of the measured values of the gyro and accelerometer sensors. Experimental result verified that our method detects pure water energy in various river environments and distinguishes between flow velocity and water level well. And we verified that vibration and position change of structures can be determined through a gyro sensor. In future research, we will work to build a secure digital twin river network by lowering the cost of supplying RF-WAV devices. Also we expect our device to contribute to securing a preventive golden time in rivers.

• 한국안전학회지
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• 제33권3호
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• pp.65-70
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• 2018

Terrain data for disaster analysis in hazardous or disaster areas is not only important but also needs to be built quickly. In particular, the introduction of drones is in the early stages of research using drones in a variety of fields such as shooting, analyzing and managing hazardous areas. It is expected that drone will be faster, safer and more effective than existing data collection method in case of small scale disaster hazard area and disaster area where equipment or manpower input is difficult. Therefore, in this study, drone shooting was performed for hazardous areas in mountainous roads located in Samcheok city, Gangwon province, and ground reference points were measured by RTK-GPS. The measured data were converted into DSM (Digital Surface Model) data by coordinate correction using Pix4D postprocessing program and then applied to the analysis of the hazard area of mountainous area. As a result, it was shown that it is effective to identify the risk by using the basic terrain data obtained from the drones.

• 한국디지털정책학회:학술대회논문집
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• 한국디지털정책학회 2006년도 춘계학술대회
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• pp.39-44
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• 2006

The purport of this paper is to deduce political implication and significance of the proposed redress scheme of 'Consumer Collective Lawsuit (hereinunder "CCL")' under way to be introduced by the Korean government via various assessments per each phase of policy implementation process. To this end, the paper classifies the subject policy (referring to CCL) implementation process into 4 phases: policy origination, policy enactment, policy advertisement, and policy execution. Based on the said classification, assessments per each phase together with pros and cons analysis have been conducted. Through the aforementioned analysis, the paper concludes the following political implication and significance of CCL under way of introduction: - 1. In the case of policy origination led by external parties, a social consensus by and from involved parties with various interests is the most critical; 2. Prior feasibility and/or suitability study is also crucial in the policy implementation procedure; 3. To mitigate inter-ministerial conflicts that might arise from the due policy making procedure, democratization of conflict settlement mechanism, and institutionalization of participation in and disclosure of policy making process are cal led upon; and 4. Prior planning wi th respect to the public relation and advertisements of the subject policy on the table poses substantial significance.

• Journal of Communications and Networks
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• 제14권4호
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• pp.396-409
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• 2012

With the proliferation of diverse wireless devices, there is an increasing concern about the security of location information which can be spoofed or disrupted by adversaries. This paper investigates the characterization and detection of location spoofing attacks, specifically those which are attempting to falsify (degrade) the position estimate through signal strength based attacks. Since the physical-layer approach identifies and assesses the security risk of position information based solely on using received signal strength (RSS), it is applicable to nearly any practical wireless network. In this paper, we characterize the impact of signal strength and beamforming attacks on range estimates and the resulting position estimate. It is shown that such attacks can be characterized by a scaling factor that biases the individual range estimators either uniformly or selectively. We then identify the more severe types of attacks, and develop an attack detection approach which does not rely on a priori knowledge (either statistical or environmental). The resulting approach, which exploits the dissimilar behavior of two RSS-based estimators when under attack, is shown to be effective at detecting both types of attacks with the detection rate increasing with the severity of the induced location error.

• Journal of Information Technology Applications and Management
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• 제23권2호
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• pp.177-194
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• 2016

This study analyzed President Park's speeches and the government's industry policy in the field of information security using cognitive map. The relationship analysis between policy tool variables and policy goal variables was employed to derive revitalization strategy of information security. This paper found that entrepreneurship revitalization has very strong causality with expansion of domestic market and global market. But, on the other hand, HR development has very weak causality with job creation and future growth driver because the labor market in the information security industry is poor and its transfer rate to other industry is very high. This study showed that this cognitive map could be characterized by a scarcity of feedback loops and a strong emphasis on the positive loops in the structure of virtuous circle. In this paper, we also constructed a comprehensive cognitive map on the policy vision of information security, showing that there are a risk of cyber threat, an opportunity of new fusion security market, information security reinforcing circle, global economic circle, and domestic market circle.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.1331-1334
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• 2002

Micropayment is an electronic payment system for small value transaction. It needs to use a little amount of resources, such as communication and computation due to its small value. In other words, the processing cost for the micropayment must be less than the value of the payment. Several kinds of transactions are suitable for micropayment, eg. the purchasing of train tickets or digital newspapers. Since micropayment systems are designed for small-amount payment the key factor for any micropayment system design is believed to be the minimization of resource consumption without compromising the standard security. In this paper, we propose an adaptive agent approach to credit-based micropayment system, which employs the concept of dynamic balancing between the resource consumption and the risk in the system. As a result of the dynamic balancing, our system not only solves the problem of global overspending but also uses fewer amount of resources than existing approaches. Our approach limits the amount of money spent by untrusted customers to all merchants. Thus, our approach provides a boundary of the global overspending. In addition, for trusted customers, our approach requires less scale of communication for verifying authorizations than all existing approaches.

• Earthquakes and Structures
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• 제18권3호
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• pp.337-348
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• 2020

Experimental testing has been considered as one of the most straightforward approaches to realize the structural behavior for earthquake engineering studies. Recently, novel and advanced experimental techniques, which combine numerical simulation with experimental testing, have been developed and applied to structural testing practically. However, researchers have to take the risk of damaging specimens or facilities during the process of developing and validating new experimental methods. In view of this, a small-scale structural laboratory has been designed and constructed in order to verify the effectiveness of newly developed experimental technique before it is applied to large-scale testing for safety concerns in this paper. Two orthogonal steel reaction walls and one steel T-slotted reaction floor are designed and analyzed. Accordingly, a large variety of experimental setups can be completed by installing servo-hydraulic actuators and fixtures depending on different research purposes. Meanwhile, a state-of-the-art digital controller and multiple real-time computation machines are allocated. The integration of hardware and software interfaces provides the feasibility and flexibility of developing novel experimental methods that used to be difficult to complete in conventional structural laboratories. A simple experimental demonstration is presented which utilizes part of the hardware and software in the small-scale structural laboratory. Finally, experimental layouts of future potential development and application are addressed and discussed, providing the practitioners with valuable reference for experimental earthquake engineering.