• 한국환경과학회지
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• 제28권12호
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• pp.1157-1169
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• 2019

We used numerical models to reliably analyze the groundwater flow and hydraulic conductivity on Jeju Island. To increase reliability, improvements were made to model application factors such as hydraulic watershed classification, groundwater recharge calculation by precipitation, hydraulic conduction calculation using the pilot point method, and expansion of the observed groundwater level. Analysis of groundwater flow showed that the model-calculated water level was similar to the observed value. However, the Seogwi and West Jeju watersheds showed large differences in groundwater level. These areas need to be analyzed by segmenting the distribution of the hydraulic conductivity. Analyzing the groundwater flow in a sub watershed showed that groundwater flow was similar to values from equipotential lines; therefore, the reliability of the analysis results could be improved. Estimation of hydraulic conductivity distribution according to the results of the groundwater flow simulation for all areas of Jeju Island showed hydraulic conductivity > 100 m/d in the coastal area and 1 - 45 m/d in the upstream area. Notably, hydraulic conductivity was 500 m/d or above in the lowlands of the eastern area, and it was relatively high in some northern and southern areas. Such characteristics were found to be related to distribution of the equipotential lines and type of groundwater occurrence.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2006년도 제32회 KOSCO SYMPOSIUM 논문집
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• pp.26-31
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• 2006

Flickering behaviors of lean premixed flame of propane/air and methane/air flame anchored by a pilot flame in a tube were investigated. Unsteady behaviors of the flame were monitored by a high speed ICCD camera and the flickering frequency was defined as the number of flame curvatures passing a fixed spatial point in a second. Unlike previous studies in which flames are in open condition so that the flickering mechanism is an unstable interaction of hot buoyant products with the ambient air, flames in this study are surrounded by a tube which means they are not open to ambient air, so that there is no interaction between hot buoyant products and ambient air. Despite the fact, there exists flickering phenomena and the flickering frequency ranges from 10 Hz to 50 Hz which is wider compared to previous studies. We relate the flickering mechanism to flame-generated vorticity and analytic solution for locally approximated flow is used. As a result, the relationship between flickering wavelength and dimensionless vorticity is acquired and the cause of higher range of flickering frequency is explained.

• 상하수도학회지
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• 제29권1호
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• pp.23-31
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• 2015

Aquifer storage transfer and recovery (ASTR) is a type of managed aquifer recharge which entails injecting water into a storage well and recovering it from a different well. It has effects of natural purification when injected water passes through aquifer medium, and can be a good way of supplying water especially in a region with poor surface water quality. This study is about an on-going effort to introduce ASTR as a solution to source water problems in coastal areas. A pilot study is being conducted in the delta of the Nakdong River. A proactive management system is incorporated to ensure the water qulity in the process of drinking water process. The system is based on the Hazard Analysis and Critical Control Point (HACCP) which is a tool originated from the food industry in order to assess hazards and establish control systems for the safety of food product. In this paper, we analyze hazardous events which can occur in the entire water supply system using ASTR as a first step to the incorporation of HACCP to drinking water production process.

• 대한간호학회지
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• 제26권3호
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• pp.653-667
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• 1996

It is important to find indicators of quality nursing care to establish the excellence of nursing practice and for the development of nursing as a profession. Caring is one of the indicators which can represent professional nursing care. The purpose of this study was to develop a measurement tool of caring that could be used as an instrument for the evaluation of quality of nursing care. The Target population for the developed tool of caring is the adult patient. The mearsurement tool of caring was developed through the following steps. (1) A list of caring behaviors was made using qualitative researches on caring that has been done in Korea. (2) Caring behaviors in nurses were selected using the list of caring behaviors developed from Watson's 10 factors of caring. (3) Items for the measurement tool of caring were developed using the caring behaviors of nurses (4) Content validity of the developed items was evaluated by an expert panel. (5) The mearsurement tool of caring was developed after a pilot study (6) Internal consistency, and construct validity of the developed tool were verified. (7) The mearsurement tool of caring with the items verified for the internal consistency and construct validity was confirmed. As a result of the study, a mearsurement tool of caring, composed of 27 items with 3 factors, was developed. The Reliability coefficient of the tool was. 9578. The tool is a 5 point Likert scale. The factors of the tool and the number of items for each factor are, 1) accessibility and availablility, 15 items ; 2) emotional support and giving information, 8 items ; 3) providing a protective environment, 4 items.

• Structural Engineering and Mechanics
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• 제42권1호
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• pp.121-129
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• 2012

All contemporary seismic Codes have adopted smooth design acceleration response spectra, which have derived by statistical analysis of many elastic response spectra of natural accelerograms. The above smooth design spectra are characterized by two main branches, an horizontal branch that is 2.5 times higher than the peak ground acceleration, and a declining parabolic branch. According to Eurocode EN/1998, the period range of the horizontal, flat branch is extended from 0.1 s, for rock soils, up to 0.8 s for softer ones. However, from many natural recorded accelerograms of important earthquakes, the real spectral amplification factor appears to be much higher than 2.5 and this means that the spectrum leads to an unsafe seismic design of the structures. This point is an issue open to question and it is the object of the present study. In the present paper, the spectral amplification factor of the smooth design acceleration spectra is re-calculated on the grounds of a known "reliability index" for a desired probability of exceedance. As a pilot scheme, the seismic area of Greece is chosen, as it is the most seismically hazardous area in Europe. The accelerograms of the 82 most important earthquakes, which have occurred in Greece during the last 38 years, are used. The soil categories are taken into account according to EN/1998. The results that have been concluded from these data are compared with the results obtained from other strong earthquakes reported in the World literature.

• 임상간호연구
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• 제14권1호
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• pp.139-150
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• 2008

Purpose: The aim of this study was to develop instrument measuring the relocation stress syndrome for patients transferred from intensive care unit to general ward in Korea. Method: For item construction, components were drawn from an extensive review of the literature, existing instruments and the result of qualitative approach. A total 48 items were selected for the first draft. Ten experts evaluated this instrument for content validity and the number of items was reduced to 29. To refine and test reliability and validity of the instrument, data were collected from the 594 patients following transfer from intensive care unit. Results: Preliminarily twenty-nine items were generated through content validity and a pilot study. Using corrected items to total correlation coefficient, this instrument was further shortened to a 25 item scale. Factor analysis extracted a total of 23 items with a 5-point Likert-type scale. Relocation Stress Syndrome (RSS) included three subscales; physical factors (12 items), Patient's recognition to health care providers (8 items), and emotional factors (3 items). The RSS established content validity, construct validity, and reliability. Conclusion: This instrument demonstrates good reliability and validity, and therefore it is an appropriate measurement of assessing relocation stress syndrome in ICU to ward transition period.

• 제어로봇시스템학회논문지
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• 제17권5호
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• pp.505-511
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• 2011

In this paper, we have developed an automatic velocity control system of a small-sized commercial treadmill (belt length of 1.2 m and width of 0.5 m) which is widely used at home and health centers. The control objective is to automatically adjust the treadmill velocity so that the subject's position is maintained within the track when the subject walks at a variable velocity. The subject's position with respect to a reference point is measured by a low-cost sonar sensor located on the back of the subject. Based on an encoder sensor measurement at the treadmill motor, a state feedback control algorithm with Kalman filter was implemented to determine the velocity of the treadmill. In order to reduce the unnatural inertia force felt by the subject, a predefined acceleration limit was applied, which generated smooth velocity trajectories. The experimental results demonstrate the effectiveness of the proposed method in providing successful velocity changes in response to variable velocity walking without causing significant inertia force to the subject. In the pilot study with three subjects, users could change their walking velocity easily and naturally with small deviations during slow, medium, and fast walking. The proposed automatic velocity control algorithm can potentially be applied to any locomotion interface in an economical way without having to use sophisticated and expensive sensors and larger treadmills.

• 정보처리학회논문지D
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• 제11D권6호
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• pp.1311-1318
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• 2004

인구증가와 발전으로 도시 집중화 현상에 따라 수도의 수요증가가 가속화되는 상태이다. 특히 물 부족현상 및 수질악화로 인한 수원확보도 어려워지고 있는 실정이다. 누수로 인한 막대한 손실을 줄이고자 컴퓨터와 인터넷을 이용하여 누수가 발생할 경우, 누수 여부를 판단하고 중앙 모니터링 센터에서 관리할 수 있는 시스템이 필요하다. 본 논문에서는 누수감지관과 TDR을 이용한 원격 상수도관망 누수 감지 시스템을 제안하였다. 유효성을 입증하기 위해 300mm 3-레이어 강관으로 파이로트 시스템을 구축하여 시뮬레이션 하였다.

• 대한음성학회지:말소리
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• 제35_36호
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• pp.37-48
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• 1998

When we hear someone's voice, even without having met the person before, we usually make up a certain mental image of the person. This study aims at investigating the relationship between the voice and the image information carried within the voice. Does the mental picture created by the voice closely reflect the real image and if not, is it related with the real image at all\ulcorner To answer the first question, a perception experiment was carried out. Speech samples reading a short sentence from 8 males and 8 females were recorded and pictures of subjects were also taken. Ajou University students were asked to participate in the experiment to match the voice with the corresponding picture. Participants in the experiment correctly match 1 female voice and 4 male voices with their corresponding pictures. However, it is interesting to note that even in cases of mismatch, the results show that there is a very strong tendency. In other words, even though participants falsely match a certain voice with a certain picture, majority of them chose the same picture for the voice. It is the case for all mismatches. It seems that voice does give the listener a certain impression about physical characteristics even if it might not be always correct. By showing that there is a clear relationship between voice and image, this study provides a starting point for further research on voice characteristics: what characteristics of the voice carry the relevant information\ulcorner This kind of study will contribute toward the understanding of the affective domain of human voice and toward the speech technology.

• 한국산업정보학회논문지
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• 제25권4호
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• pp.39-47
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• 2020

본 연구에서는 채널추정 에러와 다중 전송률 서비스를 고려하여 다중 엑세스포인트 전송전력제어 알고리즘을 제안한다. 실제 통신시스템에서는 1) 채널추정을 위해 사용하는 파일럿심볼의 갯수가 제한적이기 때문에, 수신단에서 채널추정이 완전하지 않으며, 2) 다중 전송률 서비스가 지원된다. 먼저, 제안하는 알고리즘이 다중 전송률 서비스 환경에서도 유일한 최소전력에 수렴함이 보장됨을 이론적으로 증명한다. 제안하는 전송전력제어 알고리즘은 하나의 내부루프와 하나의 외부루프로 구성된다. 실험결과를 통해 1) 내부루프 알고리즘은 전송전력 레벨의 수렴과 다중 전송률 서비스를 보장하고, 2) 외부루프 알고리즘은 채널추정 에러를 보상할 수 있음을 확인하였다.