• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.6B
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• pp.1015-1023
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• 1999

We propose nonlinear processing schemes for robust acquisition of direct-sequence spread spectrum (DS/SS) signals in wideband pulse jamming. To mitigate the interference effect due to impulse-like wideband jamming signals, the received signal is preprocessed by using the median filter, a simple order statistic filter Since only parts of the PN sequence are used for rapid acquisition, it is indispensable for analytic design of an acquisition scheme to have an appropriate model of the partial PN signal. The partial correlation of the median filtered PN signal is approximated by a two-piecewise linear model using an approximate upper bound. The acquisition performance of the proposed schemes is compared to that of other schemes. Finally, the analytic design is verified by computer simulation.

• Journal of The Korean Society of Agricultural Engineers
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• v.48 no.6
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• pp.3-13
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• 2006

Although the drought impacts are comparably not catastrophic, the results from the drought are fatal in various social and economical aspects. Different from other natural hazards including floods, drought advances slowly and spreads widely, so that the preparedness is quite important and effective to mitigate the impacts from drought. Soil moisture depletion directly resulted from rainfall shortage is highly related with drought, especially for crops and vegetations, therefore a drought can be evaluated using soil moisture conditions. In this study, SMI (Soil Moisture Index) was developed to measure a drought condition using soil moisture model and frequency analysis for return periods. Runs theory was applied to quantify the soil moisture depletions for the drought condition in terms of severity, magnitude and duration. In 1994, 1995, 2000, and 2001, Korea had experienced several severe droughts, so the SMI developed was applied to evaluate applicability in the mid-range hydrologic unit watershed scale. From the results, SMI demonstrated the drought conditions with a quite sensitive manner and can be used as an indicator to measure a drought condition.

• Journal of Korean Biological Nursing Science
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• v.13 no.2
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• pp.149-155
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• 2011

Purpose: The purpose of this research is to examine types of music (relax music or preferred music that patients have chosen) can effects on anxiety, blood pressure and pulse, and whether there are differences depending on the kinds of music in order to reduce anxiety of surgical patients using spinal anesthesia. Methods: This research's design is quasi-experimental design and non-equivalent control group pretest-posttest experimental design conducted on 60 surgical patients(experimental group 1=relax music therapy group, experimental group 2=preferred music therapy group, and group 3=control group) using spinal anesthesia. The Variables were trait anxiety, state anxiety, blood pressure, and pulse. Results: 1) In the state anxiety, there was a significant difference among the experimental groups 1, group 2 and the control group. 2) There was a significant difference in systolic blood pressure among the experimental group 1, group 2, and the control group. 3) In pulse, no significant difference among the experimental group 1, group 2 and the control group was detected. Conclusion: Regardless of the types of music, music therapy is thought to be effective nursing mediation to mitigate the state anxiety of surgical patients undergoing spinal anesthesia.

• Journal of Korean Public Health Nursing
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• v.28 no.3
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• pp.644-657
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• 2014

Purpose: The purpose of this study was to try to understand the essence of the experience early turnover of the new nurse by applying the phenomenological method and to provide basic data for a community-based management program. Method: Phenomenological approach was used to identify subjects experience. Subjects were five new nurses, with less than one year of clinical experience in clinical practice. This study used in-depth interview. Results: there were 104 meaningful sentences or phrases, with 41 generally comprehensive thema. Finally, thema were classified into 12 thema clusters. Conclusion: Finally, based on the results, some suggestions regarding management of early turnover of new nurses are needed. First, we proposed a new characterized of hospital selection method for each hospital. Second, practical training in clinical practice in the school and the community is necessary in order to reduce the real impact of new nurses. New nurses require various support elements in order to mitigate the real shock the first time they encounter clinical practice. Third, addition of work-related training and promotion of a self-esteem program will be needed. Fourth, interview opportunities with seniors who adapted successfully in clinical should be provided for new nurses. In addition, continuous communication should be provided for new nurses.

• KCI Concrete Journal
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• v.14 no.1
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• pp.23-29
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• 2002

Recent construction activities have given rise to civil petitions associated with vibration-induced damages or nuisances. To mitigate unfavorable effects of construction activities, the measures to reduce or isolate from vibration need to be adopted. In this research, a vibration-mitigated concrete, which is one of the active measures for reducing vibration in concrete structures, was investigated. Concrete was mixed with vibration-reducing materials (i.e. latex, rubber power, plastic resin, and polystyrofoam) to reduce vibration and tested to evaluate dynamic material properties and structural characteristics. Normal and high strength concrete specimens with a certain level of damage were also tested for comparisons. In addition, recycling tires and plastic materials were added to produce a vibration-reducing concrete. A total of 32 concrete bars and eight concrete beams were tested to investigate the dynamic material properties and structural characteristics. Wave measurements on concrete bars showed that vibration-mitigated concrete has larger material damping ratio than normal or high strength concrete. Styrofoam turned out to be the most effective vibration-reducing mixture. Flexural vibration tests on eight flexural concrete beams also revealed that material damping ratio of the concrete beams is much smaller than structural damping ratio for all the cases.

• International Journal of Concrete Structures and Materials
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• v.8 no.1
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• pp.43-59
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• 2014

Many bridges are subject to lateral damage for their girders due to impact by over-height vehicles collision. In this study, the optimum configurations of carbon fiber reinforced polymers (CFRP) laminates were investigated to repair the laterally damaged prestressed concrete (PS) bridge girders. Experimental and analytical investigations were conducted to study the flexural behavior of 13 half-scale AASHTO type II PS girders under both static and fatigue loading. Lateral impact damage due to vehicle collision was simulated by sawing through the concrete of the bottom flange and slicing through one of the prestressing strands. The damaged concrete was repaired and CFRP systems (longitudinal soffit laminates and evenly spaced transverse U-wraps) were applied to restore the original flexural capacity and mitigate debonding of soffit CFRP longitudinal laminates. In addition to the static load tests for ten girders, three more girders were tested under fatigue loading cycles to investigate the behavior under simulated traffic conditions. Measurements of the applied load, the deflection at five different locations, strains along the cross-section height at mid-span, and multiple strains longitudinally along the bottom soffit were recorded. The study investigated and recommended the proper CFRP repair design in terms of the CFRP longitudinal layers and U-wrapping spacing to obtain flexural capacity improvement and desired failure modes for the repaired girders. Test results showed that with proper detailing, CFRP systems can be designed to restore the lost flexural capacity, sustain the fatigue load cycles, and maintain the desired failure mode.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.1
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• pp.28-31
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• 2018

This paper investigates the ground reflection effect on the channel capacity of an orbital angular momentum (OAM) multi-mode transmission system that uses uniform circular array (UCA) antennas. The ground-reflected signals cause inter-mode interferences between the OAM modes, and lead to system performance degradation. The OAM multi-mode channel capacity severely degrades owing to the ground reflection as the transmission distance increases. Increasing the UCA height above the ground and using highly directive array elements can mitigate the ground reflection effect and increase the channel capacity.

• Proceedings of the KIEE Conference
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• 2008.10b
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• pp.209-210
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• 2008

In the case of unauthorized individuals, systems and entities or process threatening the instrumentation and control systems of nuclear facilities using the intrinsic vulnerabilities of digital based technologies, those systems may lose their own required functions. The loss of required functions of the critical systems of nuclear facilities may seriously affect the safety of nuclear facilities. Consequently, digital instrumentation and control systems, which perform functions important to safety, should be designed and operated to respond to cyber threats capitalizing on the vulnerabilities of digital based technologies. To make it possible, the developers and licensees of nuclear facilities should perform appropriate cyber security program throughout the whole life cycle of digital instrumentation and control systems. Under the goal of securing the safety of nuclear facilities, this paper presents the KINS' regulatory position on cyber security program to remove the cyber threats that exploit the vulnerabilities of digital instrumentation and control systems and to mitigate the effect of such threats. Presented regulatory position includes establishing the cyber security policy and plan, analyzing and classifying the cyber threats and cyber security assessment of digital instrumentation and control systems.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.67 no.2
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• pp.158-164
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• 2018

Wind power forecast is critical for efficient power system operation. However, wind power has high forecasting errors due to uncertainty caused by the climate change. These forecasting errors can have an adverse impact on the power system operation. In order to mitigate the issues caused by the wind power forecasting error, wind power curtailment and energy storage system (ESS) can be introduced in the power system. These methods can affect the economics of wind power resources. Therefore, it is necessary to evaluate the economics of the methods for mitigating the wind power forecasting error. This paper attempts to analyze the economics of wind power curtailment and ESS operation for mitigating wind power forecasting error. Numerical simulation results are presented to show the economic impact of wind power curtailment and ESS operation.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1316-1322
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• 2009

The multicarrier system is in the limelight for broadband wireless communications due to its spectral efficiency. Filtered multitone(FMT) system uses a filter that has several symbol periods duration. Using long-period filter causes a performance degradation because of intersymbol interference in multipath fading channels. In this paper, we propose a simple equalization method which can reduce the ISI due to the wireless channels. The proposed equalization method compensates the ISI by subtracting the estimated ISI components from the current symbol using one-tap equalizer. The performance of the proposed system is verified through theoretical analysis and simulation results show that the proposed system can mitigate the effect of ISI significantly.