• Proceedings of the KOR-BRONCHOESO Conference
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• 1977.06a
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• pp.8.5-9
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• 1977

Foreign bodies in food and air passage, especially the latter in infants and children requires emergency treatment. The frequent symptoms are coughing, wheezing, and dyspnea, So may be confused as asthma, pneumonia and acute Laryngitis. The species and incidence of the foregin bodies are variable according to the age, method of life, environment and economic condition. The authors experienced 35 cases of foreign body in air passage during the period of last 3yrs which were treated by ventilating Bronchoscopy, and thoractomy in this hospital. One of them was lead to death. The authors analysed above cases and report with it's literature consideration. Results: 1. The prevalent foreign bodies were peanut, metal, food particles in order of frequency. 2. In frequent symptoms were dyspnea, coughing and wheezing in the order. 3. In the age incidence, 48% of the foreign bodies were 1∼5yrs. 4. In sex distribution, male to female ratio was 2.1: 1 5. In duration of lodgment, 65% of the foreign body were removed within 24hrs. 6. Most prevalent site of the foreign body was Rt. main bronchus Rt. to Lt. ratis was 2 : 1 was 7. Treatment was done; 25 cases were by ventilating bronchoscopy.

• KIEAE Journal
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• v.10 no.5
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• pp.187-194
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• 2010

Heavy-weight floor impact sound insulation performance criteria have been effective in Korea since the regulation which enforces the standard thickness of slabs in domestic apartment houses should be constructed by 180mm or 210mm was adopted. But every slab does not satisfy this criteria. So, review on existing floor impact sound insulation performance is needed to propose some basic materials for the revision of rating method. To achieve this goal, 63 field test data were checked and analyzed. The results of this study are as follows ; 1) The 210mm thickness slab has the characteristics of deeper level decrease above 120Hz frequency band than that of 180mm thickness slab's. 2) 27.5% of 180mm thickness slabs were satisfied the floor impact sound insulation performance criteria, whereas 65% of 210mm slabs do. 3) Among the main contribution frequency bands for the determination of single rating index, 63Hz was shown as the most contributive band in 210mm slabs. 4) In comparison of single rating index between bang machine test and ball test. there is a big difference between the two and this phenomenon is frequent in 210mm slab results. 5) Rating Methods for the analysis of cross-correlation between the amount of rating, the usefulness of the arithmetic mean could be secured.

• Environmental and Resource Economics Review
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• v.27 no.3
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• pp.545-567
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• 2018

This study applied and compared Poisson model, negative binomial model, zero inflated Poisson model, and zero inflated negative binomial model to estimate determinants of employed labour quantity. To estimate each of models, this study used fisheries census data which were obtained at microdata integrated service running by Statistics Korea. The study selected zero inflated negative binomial model according to the Vuong test and Likelihood-ratio test. In addition, the study estimated fishing village's practical changes on employed labour quantity as analyzing changes from 2010 to 2015. The results showed that the household with fishing vessels and high selling price had a significant effect on decrease of the labour quantities. Meanwhile, the longer work experience of the household, the more significant the increase in the labour quantities. In conclusion, this study presented that capitalized fishing household and the acceleration of aging had a significant impact on the change in the labour quantities.

• Science of Emotion and Sensibility
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• v.7 no.2
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• pp.141-148
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• 2004

This paper proposed a new time adapted threshold using the standard deviations of Wavelet coefficients after Wavelet transform by frame scale. The time adapted threshold is set up using the sum of standard deviations of Wavelet coefficient in cA3 and weighted cDl. cA3 coefficients represent the voiced sound with low frequency and cDl coefficients represent the unvoiced sound with high frequency. From simulation results, it is demonstrated that the proposed algorithm improves SNR and MSE performance more than Wavelet transform and Wavelet packet transform does. Moreover, the reconstructed signals by the proposed algorithm resemble the original signal in terms of plosive sound, fricative sound and affricate sound but Wavelet transform and Wavelet packet transform reduce those sounds seriously.

• International Area Studies Review
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• v.14 no.3
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• pp.178-204
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• 2010

This study analyzes the effects Korea's grant aid to 53 African countries, focusing on its impacts on improving HDI (Human Development Index) of each recipient country, through panel data analysis. According to the OLS panel analysis, Korea's grant aid on information and communication (IC) sector showed positive and significant correlation with HDI, but aid on administrative system and environment showed negative correlation with HDI. Also, according to the fixed effect panel analysis, aid on IC sector showed positive correlation with HDI, but aid on administrative system showed negative correlation with HDI. In particular, effects of aid was different across the region. In North African region, aid on health improved HDI. However, in Sub-Saharan African region, aid on IC was more effective in improving HDI. This results imply that grand aid on Africa needs to be coordinated strategically across regions and sectors. This paper is meaningful in providing ways that can be mutually beneficial both to donor and recipient countries of grant aid.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.20 no.1
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• pp.40-53
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• 2021

Recently, shared dockless e-scooter usage has rapidly increased, rather than the station-based shared mobility service, because of convenience. This transition leads to new social problems in urban areas such as increased traffic accidents and hindrance of pedestrian environments. In this study, we analyze the usage characteristics of shared e-scooters in Seoul, and identify factors influencing demand for shared e-scooters by developing a negative binomial regression model. As a result, the usage characteristics show that the average trip distance, the average trip duration, and the average trip speed were 1.5km, 9.4min, and 10.3km/h, respectively. Demographic factor, transport facility factors, land use factors, and weather factors have statistically significant impacts on demand for shared e-scooters. The results of this study will be used as basic data for suggesting effective operation strategies for areas with higher shared e-scooter demand and for establishing transport policies for facilitating shared e-scooter usage.

• The Journal of the Acoustical Society of Korea
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• v.29 no.7
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• pp.411-421
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• 2010

A time-reversal mirror (TRM) is useful in diverse areas, such as reverberation ing, target echo enhancement and underwater communication. In underwater communication, the bit error rate has been improved significantly due to the increased signal-to-noise ratio by spatio-temporal focusing. This paper deals with two issues. First, the optimal number of array elements for a given environment was investigated based on the exploitation of spatial diversity. Second, an algorithm was developed to determine the optimal location of the given number of array elements. The formulation is based on a genetic algorithm maximizing the contrast between the foci and area of interest as an objective function. In addition, the developed algorithm was applied to the matched field processing with ocean experimental data for verification. The sea-going data and simulation showed almost 3 dB improvement in the output power at the foci when the array elements were optimally distributed.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.11
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• pp.997-1006
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• 2009

Organic removal efficiency and methane production rate, a feasibility of power generation from biogas, and the optimum conditions for membrane operation were evaluated for the pilot scale (5 tons/day) two-phase anaerobic digestion coupled with ultra filtration (TPADUF) system fed with garbage leachate. The TPADUF system is consisted of a thermophilic acidogenic reactor, a mesophilic methanogenic reactor, and an UF membrane. When garbage leachate with 150 g/L of TCOD was fed to the TPADUF up to organic loading rate (OLR) of 11.1 g COD/L/d, the effluent TCOD was lower than 6 g/L and the average removal efficiencies of TCOD and SCOD were higher than 95%. The methane composition of the gas was 65%, and the methane yield was 39 $m^3/m^3$ garbage leachatefed, 260 $m^3$/tons $COD_{added}$, or 270 $m^3$/tons $COD_{removed}$, even there was some gas leak. The power production per consumed gas was 0.96 kWh/$m^3$ gas or 1.49 kWh/$m^3$ methane. This lower power production efficiency mainly due to the small capacity of gas engine (15 kW class). The membrane was operated at the average flux of 10 L/$m^2$/hr. When the flux decreased, washing with water and chemical (NaOCl) was conducted to restore the flux. In the TPADUF system, optimum pH could be maintained without alkali addition by recycling the membrane concentrate or mixed liquor of the methanogenic digester to the acidogenic reactor. Also, partial production of methane in the acidogenic reactor had a positive effect on lowering the OLR of the methanogenic reactor.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.655-662
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• 2012

Gas leakage in an oil refinery causes damage to the environment and unsafe conditions. Therefore, it is necessary to develop a technique that is able to detect the location of the leakage and to filter abnormal gas-leakage signals from normal background noise. In this study, the adaptation filter of the finite impulse response (FIR) least mean squares (LMS) algorithm and a cross-correlation function were used to develop a leakage-predicting program based on LABVIEW. Nitrogen gas at a high pressure of 120 kg/$cm^2$ and the assembled equipment were used to perform experiments in a reverberant chamber. Analysis of the data from the experiments performed with various hole sizes, pressures, distances, and frequencies indicated that the background noise occurred primarily at less than 1 kHz and that the leakage signal appeared in a high-frequency region of around 16 kHz. Measurement of the noise sources in an actual oil refinery revealed that the noise frequencies of pumps and compressors, which are two typical background noise sources in a petrochemical plant, were 2 kHz and 4.5 kHz, respectively. The fact that these two signals were separated clearly made it possible to distinguish leakage signals from background noises and, in addition, to detect the location of the leakage.

• Environmental and Resource Economics Review
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• v.22 no.2
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• pp.215-250
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• 2013

The term, "resource curse", is widely used to describe how countries rich in natural resources, such as oil, natural gas, and certain minerals, are unable to utilize that wealth to boost their economies. Contrary to previous research on the topic, this study has demonstrated that natural resources have a strong positive correlation with a country's economy. It likewise confirmed that this result is robust with broad sets of exogenous variables, and that the positive impact of natural resources on the economy remains significant with the inclusion of capital stock per worker. In this sense, it is doubtful that resource curse actually exists in the long-run. On the other hand, this study tested whether the quality of institutions has any relation with natural resource endowments if the positive effect of natural resource endowments on the gross domestic product (GDP) is adequately controlled for. In contrast to findings of Alexeev and Conrad (2009), if the former Soviet Union (FSU) countries are included, it seems that there might be a negative and statistically significant relationship between large endowments of natural resources and the quality of institutions. However, this negative relationship loses its significance and some positive albeit insignificant relationships are confirmed in a considerable number of cases when the FSU countries are excluded in the sample. That is, the negative relationship results from the inclusion of the FSU countries. This result is believed to happen by a temporary coincidence of events, a natural resource windfall and political and economic instability during the transition of the FSU countries. Therefore, the argument that resource abundance harms the institutional quality is confirmed to be a little groundless.