• The Korean Journal of Community Living Science
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• v.22 no.4
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• pp.623-635
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• 2011

Over the past few decades, the proportion of elderly people with depression in Korea has been rapidly increasing. The purpose of this study is to explore relative effects of health and family factors on geriatric depression. The data sources are from Korean Longitudinal Study of Aging(2008). The Analysis sample consists of 4,040 cases. Analysis results show that there is a significant variability in geriatric depression according to sociodemographic characteristics, health characteristics, and family characteristics. Hierarchical logistic regression analyses are employed to assess the causal relationship between health characteristics and geriatric depression. Model II showed that ADL(exp(B)=1.732), having difficulties due to sight deterioration(exp(B)=1.398), having difficulties due to masticatory force deterioration(exp(B)=1.414), having difficulties due to pain(exp(B)=2.435), and subjective health status(exp(B)=2.010) are reported as predictors of geriatric depression. Namely, the probability of having geriatric depression of the above predictors has been 1.7 times, 1.4 times, 1.4 times, 2.4 times. 2.0 times higher than normal figures. Among health characteristics, pain is the most prevalent factor. Model III showed that as for family characteristics, coresiding with children(exp(B)=1.312) and frequency of contacting with children by phones, letters, or emails(exp(B)=1.477) are reported as predictors of geriatric depression. Key findings are that health factors have larger effects than family factors on geriatric depression.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.469-474
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• 1990

The implementation of modern guidance law derived from optimal control theory requires accurate current states of target, for example, position, velocity and acceleration etc. But there is no sensors that measure the target states directly. So they are estimated from measurable data. For atmospheric missile engagement, direct application of the modern guidance laws may result In deterioration of Intercept performance because of poor observability associated with angles only-measurements by passive seeker and homing geometry. In this paper, a trajectory modulation method called "adaptive Intermittent maneuvers" is added to the modern guidance law, so the observability is enhanced and, consequently, improved the intercept performance. The estimation algorithm called "modified gain pseudo-measurement filter" is used for tracking filter. It is assumed that the passive seeker measure the angles between line of sight and Inertial frame. The Monte-Carlo simulation for realistic air-to-air Intercept scenario are conducted to demonstrate the effectiveness of intermittent maneuvers.ermittent maneuvers.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.494-498
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• 2011

Satellite digital multimedia broadcasting (S-DMB) systems use gap fillers (GFs) to provide wireless multimedia services to non-line-of-sight locations. GFs act as repeaters, and S-DMB systems require GF networks in order to guarantee mobile reception. Each GF covers a cell or sector. In order to provide contiguous coverage of an area comprising two or more cells or sectors, multiple GFs are needed. However, when multiple GFs are situated close to each other, interference is likely to occur. As a result, in this study, we have investigated system-level environments for planning the design of interference-free GF networks in S-DMB systems. Our investigations revealed that S-DMB services are unavailable because of quality deterioration caused by interference when the delay attributable to a GF and the satellite signals exceeds ${\pm}$256 chips and the distance between the GF and its reception terminal is greater than 4.6 km. On the basis of this analysis, we conducted a field test that confirmed that the above-mentioned time delay can be controlled in such a way as to ensure high quality S-DMB services.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.121-132
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• 2008

Recently, there is a growing interest in promoting safe and convenient roadway and traffic conditions for elderly drivers. This paper analyzed the driving characteristics, self recognition, and any inconvenience of elderly drivers over age 65 through an extensive survey, and drew some action plans to improve the driving conditions for elderly drivers. Survey results showed that the major trip purposes of the elderly driver were found to be commuting(50%) and business(33%), and this pattern was similar to the general drivers. The elderly drivers are interested in "safety", but "brand recognition" was the more important factor for the general drivers in the process of vehicle selection. The elderly drivers had no technical skill difference in driving as compared to the general drivers, but they fully recognized the physical deterioration such as reaction time and sight distance. In addition, the elderly drivers had a tendency to feel psychological contraction as to high workload driving conditions, thus it was necessary to make safe driving conditions by improving the design elements of traffic control devices on the roadways including visibility.

• Journal of the Korea Institute of Construction Safety
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• v.2 no.1
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• pp.36-44
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• 2019

$21^{st}$ century is digitally civilized era. Technologies such as AI, Iot, Big Data, Mobile and etc makes this era digitally advanced. These advancement of the technology greatly impacted detection range of the radar. Human's eye sight can see about 20Km and hear 20 ~ 20000 Hz. These limitations can be overcome using radar. This radar technology is used in military, aircraft, ship, vehicle and etc. to replace human eye. However, radar technology is capable of making False Alarm Rate. This document will propose the fix of these problems. Radar's distortion includes beam refraction, diffraction and reflection. These inaccurate data result in deterioration of human judgements and my cause various casualties and damages. Radar goes through annual testing to test how many false alarm is being produced. Normal radar usually makes 10 to 20 False alarms. In emergency situation, if operator were to follow this false alarm, this might result in following false object or take 12 more seconds to follow the right object. This problem can be overcome by using different radar data from different places and angles. This helps reduces False Alarm rate and track the object twice as fast.