• Quality Improvement in Health Care
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• v.7 no.1
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• pp.72-89
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• 2000

Background : Various types of protective footwear have been used to minimize bacterial contamination in operating rooms. In recent years, debate has arisen concerning the need for use of such protective footwear. This study was designed to provide useful data about choosing shoes most suitable for the surgical environment. Methods : Between November, 1999 and January, 2000, we performed this experimental study by comparing effect of three types of shoes (i.e., disposable shoescover, operating room-restricted shoes, and ordinary shoes) on bacterial contamination of operating rooms equipped with two different ventilation systems (i.e., high air-change, low air-change) respectively. Data were collected during two- hour sham operations in which subjects and their activities were strictly standardized. Bacterial flora were sampled from the study area floor and air colony counts were measured. Results : In experiments involving high air-change ventilation system, there was a significant difference of floor contamination between three types of shoes, but no difference of air contamination. Under low air-change system, there was a significant difference of both floor and air contamination between three types of shoes. Conclusion : The results show that protective footwear would be unnecessary in the operating room with high air-change ventilation system, but it is important to choose suitable shoes carefully under low air-change system. Therefore, the use of outdoor shoes can be considered under high air-change system, but it would seem sensible to apply their first use in less bloody operations at the day surgery center or out-patient department to prevent transfer of body fluid into the outside environment.

• Journal of the Korean Society for Railway
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• v.16 no.3
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• pp.196-201
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• 2013

As there is no failure data for the entire lifecycle of a product, when analyzing reliability measures based on early failure data only, there may be a significant error between the estimated mean life and the real one, because it can be underestimated, or on the other hand, it can be overestimated when analyzing reliability measures based on a large amount of censored data with the failure data. To resolve the issue, this study proposes an optimal sampling estimation procedure that selects the proportion of censored data to estimate the optimal distribution with the idea that the estimated distribution could be approximated as closely as the real life distribution. This would work if we sampled the optimal proportion on the censored data, because failure data has real intrinsic distribution in any situation. We validate the proposed procedure using an actual example. If the proposed method is applied to the maintenance policy of TWC (Train to Wayside Communication) system, then we can establish the optimal maintenance policy. Thus, we expect that it will be effective for improvement of reliability and cost savings.

• Journal of environmental and Sanitary engineering
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• v.14 no.2
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• pp.56-67
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• 1999

This study was performed to suggest the basic data and plans for the establishment of safe water supply plans in simple water supply piped system in the rural areas. In 4 different places, 24 points of water sources 36 points of taps from water sources were sampled. Of the whole 60 points, 55 points were ground water and 5 points were surface water. 14 items were measured for the analysis of water quality on each samples. The measured items were analyzed again by statistical method ; cluster analysis and principle components analysis. The results of this study are as followed. 1) In water quality analysis on water sources, 4 items, bacteria, E.coli, NH3-N and Fe exceed the standard. Of 24 points, 20 points(83%) on bacteria, 1 point(4%) on NH3-N and Fe exceed the standard. 2) In water quality analysis on near and remote taps, 4 items, bacteria, E.coli, NH3-N and Fe , exceed the standard. Of 36 points, 20 points (81%) on bactria, 1 pint(3%) on NH3-N and Fe exceed the standard. 3)Cluster analysis on water quality shows the differences by the kinds of water sources, geographical characteristics and distance from water sources. 4) Principle components analysis on ground water shows that Factor 1 and Factor 3 are natural fluctuation by the content of soil. Also, Factor 2 and Factor 4 are penetration of pollutants to underground. Therefore, it is needed to take deeper ground water in order to prevent from pollution in the areas which have ground water as water source . 5) Principle components analysis on surface water shows that Factor 1 is penetration of vacteria from surface to water source when rainfalls. Also, Factor 2 is fluctuation of water quality by the geographical characteristics. Therefore, the counterplans against non-point pollution source must be taken. Filtration and disinfection facilities are needed in the areas which have surface water as water source.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.43-48
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• 2009

We constructed a simple wavelength readout system for a tunable fiber laser which was used for a fiber Bragg grating sensor array system. A quadrature sampling method was used to demodulate wavelength variations of the tunable laser which consisted of a SOA(semi-conductor optical amplifier) and a fiber-optic Fabry-Perot filter. Internal triggers, which have a 90 degree phase period, have been generated by using a double-pass Mach-Zehnder interferometer. From Lissajous plots with quadrature sampled data, a mean phase error of ${\sim}2.51$ mrad was obtained. From the wavelength readout experiments, an accurate and fast linear wavelength demodulation has been confirmed.

• Journal of the Korean Society of School Health
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• v.10 no.1
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• pp.75-86
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• 1997

Blindness or visually handicaps are found to be an important factor destroying lifestyles as well as a physical problem. According to the data of handicapped person's(v.h.p) registered in Korea, the number of v.h.p. has not decreased. Especially, visual handicapped adolescents (v.h.a.) suffer from an insufficiency of social support under the current education system. There is a special education system for v.h.a. in Korea, and, as a result v.h.a.'s are educated separately from general students and communites. Compared with the self-conception of general students, v.h.a.'s have a more negative self-conception. Among former studies 51.7% of v.h.p's are not in good health. This, of course, means that their handicap impacts on other health problems. The first purpose of this study is to find out the causes of disease and the degree of social support, self-esteem, health management behavior provided and then to analyze the effect of self-esteem and social support on their behavior. To accomplish these purposes, visually handicapped the middle and high school students in Seoul city and Kyung-gi province were selected and 300 students sampled. The main results are as follows : 1) The highest specific handicap is impaired lenses (19.7%). 2. There were high correlations between health management behavior, self-esteem, and social support. 3. Social support is a more important variable than self-esteem on health management behavior. 4. Age of entry and length of stay in their special dormitories, and teacher's support account for 16% of psychological health management behavior 5. Age of entry in their special dormitory and total degree of social support account for 12% of preventive health behavior.

• Korean Journal of Social Welfare
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• v.48
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• pp.150-178
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• 2002

The elderly have higher potential for contracting chronic diseases and suffering from development of a complication. Also, the extended old age period leads the elderly to demand more medical services. All those facts indicate that the elderly need more medical services than any other age groups. Consequently, medical care for the elderly with chronic diseases causes high costs burden. However, there is few studies researching the financial burden of chronic illness of the elderly. This study aimed to 1) understand how much the elderly with chronic diseases pay for medical expenses; 2) find out some specific factors related to health care financial burden; 3) suggest the alternative policies to decrease excessive financial burden of caring for the elderly with chronic illness. National Health and Nutrition Survey, which was surveyed by the Korea Institute for Health and Social Affairs in 1998, was used in this study. 4,707 persons with chronic diseases out of 5385 persons over age 60 were selectively sampled. Using SPSSWIN, correlation analysis, T-test, ANOVA and Regression were used as statistical methods in this study. Stepwise multiple regression was employed to analyze the data with a ratio of health care expenditure to income(financial burden) as a dependent variable. Out of Korean old people, 87% had the chronic diseases and their health care financial burden rate showed the average of 17.9%, which meaned they expended almost 20% income to buy medical services. The variables having a great influence on financial burden were monthly income, activity, limitation and single household of an old person. The excessive financial burden was experienced by people who had more than 4 activity limitations(37.1%) and were in the lowest Income level(32.6%), and single household of an old person(31.4%). The new policies should be considered to 1) reduce the financial burden in these groups and to develop the sliced medical cost system considering the characteristics of chronic illness and income level; and 2) develop the medical management system to care for the elderly with chronic illness.

• Health Policy and Management
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• v.21 no.2
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• pp.159-178
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• 2011

Korea ranks high among the OECD member countries with a high out-of-pocket share. In 2006, the government implemented in full scale the policy of extending the health insurance benefit coverage. Included in the policy are lowering the out-of-pocket share of patients of serious case and expanding the medical bill ceiling system to mention just a few. This study proposes to confirm effectiveness of the benefit extension policy by identifying changes in 'out-of-pocket expenditure as a share of the ability to pay' and 'incidence rate of catastrophic health care expenditure' of each individual household as manifested before and after the benefit extension policy was implemented. The 1st and 3rd year data from the Korea Welfare Panel Study (KoWePS), conducted by the Korea Institute for Health and Social Affairs (KIHASA), were used for the analysis, where low-income households and ordinary households are sampled separately. While the absolute amount of 'out-of-pocket expenditure' occurred to the average household increased for the period 2005-2007, the 'out-of-pocket expenditure as a share of the ability to pay' decreased. At the same time, the share decreased in the case of low-income households and households with patients of chronic or serious case as contrasted with ordinary households. 'Incidence rates of catastrophic health care expenditure' of ordinary households for 2007 stood at 14.6%, 5.9% and 2.8% at the threshold of 10%, 20% and 30%, respectively. The rates decreased overall between 2005 and 2007, while those of low-income households with patients of serious case statistically significantly increased. An analysis of this study indicates that it is related with the medical bill ceiling system regardless of incomes introduced in 2007.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.7
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• pp.1433-1438
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• 2009

The purpose of this study is to investigate how the ignition spark timing conversion influences the engine performance of LPG/Gasoline Bi-Fuel engine. We propose the control system which can advance the ignition spark timing in LPG fuel mode more than used in gasoline fuel mode. In order to investigate the engine performance during combustion, engine performance are sampled by data acquisition system, for example cylinder pressure, pressure rise rate and heat release rate, while change of the rpm(1500, 2000) and the ignition timing advance($5^{\circ}$,$10^{\circ}$,$15^{\circ}$,$20^{\circ}$) As the result, between 1500rpm and 2000rpm, the cylinder pressure and pressure rise rate was increased when the spark ignition was advanced but pressure rise rate at $20^{\circ}$was smaller value. Also, the heat release rate at 1500rpm was increased but it was lower around $20^{\circ}$at 2000rpm.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.449-458
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• 1996

Most of the conventional electrocardiowaphs foil to detect signals other than P-QRS-T due to the limited SNR and bandwidth. High-resolution electrocardiography(HRECG) provides better SNR and wider bandwidth for the detection of micro-potentials with higher frequency components such as vontricular late potentials(LP). We have developed a HRECG using uncorrected XYZ lead for the detection of LPs. The overall gain of the amplifier is 4000 and the bandwidth is 0.5-300Hz without using 60Hz notch filter. Three 16-bit A/D converters sample X, Y, and Z signals simultaneously with a sampling frequency of 2000Hz. Sampled data are transmitted to a PC via a DMA-controlled, optically-coupled serial communication channel. In order to further reduce the noise, we implemented a signal averaging algorithm that averaged many instances of aligned beats. The beat alignment was carried out through the use of a template matching technique that finds a location maximizing cross-correlation with a given beat tem- plate. Beat alignment error was reduced to $\pm$0.25ms. FIR high-pass filter with cut-off frequency of 40Hz was applied to remove the low frequency components of the averaged X, Y, and Z signals. QRS onset and end point were determined from the vector magnitude of the sigrlaIL and some parameters needed to detect the existence of LP were estimated. The entire system was designed for the easy application of the future research topics including the optimal lead system, filter design, new parameter extraction, etc. In the developed HRECG, without signal averaging, the noise level was less than 5$\mu$V$_rms RTI$. With signal averaging of at least 100 beats, the noise level was reduced to 0.5$\mu$V$_rms RTI$, which is low enough to detect LPs. The developed HRECG will provide a new advanced functionality to interpretive ECG analyzers.

• Ecology and Resilient Infrastructure
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• v.9 no.1
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• pp.59-67
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• 2022

The purpose of this study is to provide essential data necessary to assess ecological flow requirements by understanding habitat conditions for fish species through monitoring an ecological environment in the Korea stream (Dal Stream) and building related database. On-site surveys were conducted for identifying ecological and habitat conditions at the four monitoring sites. Fish sampling was carried out at the selected four sites (St.) during the period ranging from September, 2008 to September, 2009. At the four sampling sites, we measured water surface elevation, depth and velocity at the cross-sections. Optimal Ecological Flowrates (OEFs) were estimated using the Habitat Suitability Index (HSI) established for four fish species Zacco koreanus (St.1), Pungtungia herzi (St.2), Coreoleuciscus splendidus (St.3), and Zacco platypus (St.4) selected as icon species using the Physical HABitat SIMulation system (PHABSIM). Eighteen species (56.3%) including Odontobutis interrupta, Coreoperca herzi and C. splendidus were found endemic out of the 32 species in eight families sampled during this study period. The endangered species was collected Acheilognathus signifier, Pseudopungtungia tenuicorpa and Gobiobotia macrocephala, and this relative abundance was 9.4%. The most frequently found one was Z. platypus (31.3%) followed by C. splendidus (17.6%) and Z. koreanus (15.7%). The estimated IBI values ranged from 27.3 to 34.3 with average being 30.3 out of 50, rendering the site ecologically poor to fair health conditions. For C. splendidus (St.3), the dominant fish species in the stream, the favored habitat conditions were estimated to be 0.3-0.5 m for water depth, 0.4-0.7 m/s for flow velocity and sand-cobbles for substrate size, respectively. An OEFs of 8.5 m³/s was recommended for the representative fish species at the St.3.