• Proceedings of the Korean Society of Computer Information Conference
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• 2015.01a
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• pp.115-118
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• 2015

최근 평균수명이 증가와 더불어 삶의 질이 중요시하고 건강한 삶을 누리고자하는 인류의 염원은 보건의료라는 보편적 가치에 동반 상승할 수 있는 산업과의 결합이 의료관광이라는 새로운 관광시장을 형성하였다. 의료관광은 시장규모가 1억 달러 이상에 이를 것으로 예상되는 고부가가치 산업이다. 또한 외국인을 상대 의료관광은 체류기간이 길고 지출비용도 일반 관광객의 3배 이상으로 지역경제 활성화에 큰 공헌을 하는 대표적인 신 성장 동력산업으로 보고 있다. 더불어 의료관광 추세가 의료서비스를 받으면서 휴양 레저 문화활동을 함께 즐기는 방향으로 발전될 것으로 예측하고 최근 단순 치료 목적이 아닌 방향으로 선회하고 있다. 그러나 국가 정책적 산업으로서 육성에 박차를 가하고는 있으나 의료 기반시설이 열악하고 관련 규정 및 제도적 미비점이 지금의 의료관광 산업에 발맞추지 못하는 실정이다. 이는 주변 경쟁국에 비해 인식부족과 세계시장에 대한 마케팅 활동 부족 및 의료관광 상품의 다양성 부족 등과 함께 의료관광이 활성화하기 위하여 여러 가지 제약이 되는 정책적 문제점들이 있다. 따라서 본 논문에서는 현행 우리나라의 의료관광에 대한 정책적 과제를 살펴보고 이를 개선하기 위한 제도적 개선방안을 모색하고자 한다.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.68-75
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• 2016

A set of lab-scale polymer synthetic fiber packed column wetlands composing three columns (CW1, CW2 and CW3) with different hydraulic regimes, recirculation frequencies and pollutant loading rates, were operated in 2012. Synthetic fiber tested as an alternative wetland medium for soil mixture or gravel which has been widely used, has very high pore size and volume, so that clogging opportunity can be greatly avoided. The inflow to the wetland was artificial stormwater. All the wetlands achieved effective removal of TSS (94%~96%), TCOD (68%~73%), TN (35%~58%), TKN (62%~73%) and NH4-N (85%~ 99%). Particularly, it was observed that COD was released from the fiber during one distinct period in all wetlands. This was probably due to the degradation of polymer fiber, and the released organic matters were found to serve as carbon source for denitrification. In addition, with longer retention time and frequent recirculation, lower effluent concentration was observed. With higher pollutant loading rate, higher nitrification and denitrification rates were achieved. However, although organic matters were released from the fiber, the lack of carbon source was still the limiting factor for the system since the release persisted only for 40 days.

• Proceedings of KOSOMES biannual meeting
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• 2007.11a
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• pp.97-102
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• 2007

The piggery wastewater is the major source of the water pollution problem in the rural area. The treatment alternatives for piggery wastewater are limited by the characteristics of both high organic and nitrogen(N) content. In order to investigate an efficient N removal system, the thermophilic aerobic digestion process was examined. The experiment was investigated organic and nitrogen removal efficiency at various HRTs and air supply volume. The results of semi-continuous experiment indicated that a higher removal of the soluble portion of COD was achieved with the longer HRTs. However, the inert portion of COD in piggery wastewater was not much changed by thermophilic aerobic digestion. In addition, with the higher HRT of 3 days, up to 79% of NH4-N removal efficiency was achieved. Lower the HRTs, a decrease of NH4-N removal was founds. The gas samples from the lab reactor were analyzed along with the N content in influent and effluent. The N2O formation in our system indicates a novel aerobic deammonification process occurred during the thermophilic aerobic digestion. Both N02 and N03 were not presented in the effluent of thermophilic aerobic digester. With the HRT of 3 days, 36.4% of influent N(or 57.5% removal N) was aerobically converted to N2O gas. The ammonium conversion to N2O gas significantly decrease to 4.5% at low HRT of .05 day..

• The Journal of the Convergence on Culture Technology
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• v.6 no.2
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• pp.9-14
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• 2020

This paper aims to figure out the impact of employee's travel experience on their happiness and motivations to work. To this end, targeting 405 employees in Daegu, Gyeongsangnamdo, and Gyeongsangbukdo, SPSS Statistics 18.0 program was applied to analyze. Frist, in travel experience depending on general characteristics of the targets, there was significant difference in gender, educational background, and occupation but there was significant difference in age, marital status, and average income. Second, there was difference in travel experience depending on frequency of domestic travel but no difference in terms of the period of stay. On the other hands, travel experience depending on frequency of overseas travel showd significant difference in sub-factor, human network experience. There was significant difference in overseas travel depending on period of stay. Third, travel experience showed positive relation in employee's motivation to work and happiness. Fourth, as a result of reviewing impact of travel experience on employee's motivations to work and happiness, sub-factors like emotional, behavioral, relational experiences affected motivations to work significantly. Emotional experience and cognitive experience didn't affect significant impact. And sub-factors of travel experience like emotional, cognitive, and behavioral experiences affected happiness significantly. Emotional and relational experience were not significant. From the research above, it turned out that travel experience gives happiness to employees and provokes positive thinking and their motivations to work.

• Korean Journal of Environmental Agriculture
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• v.18 no.2
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• pp.191-195
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• 1999

An integrated wastewater treatment pond system is developed for treatment and recycling of excreta from dairy cattle. It is composed of three ponds in series. A pit with a capacity of $10m^3$, 2-day hydraulic residence time, and overflow velocity of $1.5m^3m^{-2}day^{-1}$ is located internally in primary pond. It is designed for efficient sludge sedimentation and effective methane fermentation. It receives $5m^3/day$ of diluted cattle excreta by the water used for clearing stalls. A submerged gays collector for the recovery of methane is installed on the top of the pit. The average BOD_5 concentration of influent is 398.7mg/l. That of the effluent from primary pond is 49.2mg/l. About 88% of BOD_5 are removed in primary pond. It is assumed that about 60% of the influent BOD_5 is removed in the pit and that almost all of the carbon of the removed BOD_5 in the pit is converted to methane and carbon dioxide. Methane fermentation of the pit is well established at $16^{\circ}C$. This phenomena results from temperature stability, complete anaerobic condition, and neutral pH of the pit. Gas from the collector is almost 90% methane, less than 9% nitrogen, and less than 1% carbon dioxide. Thus a purified methane is produced, which can be used as energy source.

• Journal of the Korean GEO-environmental Society
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• v.8 no.6
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• pp.21-28
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• 2007

The objective of this study was to investigate the effect of hydraulic retention time (HRT) on removal efficiencies of organic matter, nitrogen and phosphorus in MBR-RO process for treating synthetic sewage. In MBR process, turbidity was less than average 2 NTU and average removal efficiency showed more than 99% during the operation period(MBR 105 day). As a result of HRT variation, average removal efficiencies of $COD_{Cr}$ on HRT 6, 12, 18 and 24hour were about 72.4, 84, 88.6 and 92.5%, respectively. The $NH_4{^+}-N$ removal efficiency was about 60.2 85.5, 91.3 and 92.2%, respectively. T-N and T-P removal efficiencies increased from 53.7 and 56.8 to 82.5 and 86.4%, respectively as the HRT increased from 6 hour to 24 hour. In RO process, average removal efficiencies of color and $COD_{Cr}$ in RO permeate were about 99.9% and 96.8%, respectively. Also, removal efficiencies of T-N, $NH_4{^+}-N$, $NO_3{^-}-N$ and T-P were all above average 90%.

• Survey Research
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• v.12 no.1
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• pp.65-88
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• 2011

This study analyzed the work and retirement behavior of middle- and old-aged Koreans using panel-data based multi-state life table models. Compared to previous studies that have mainly focused on gender differences in the work and retirement behavior, this study also analyzed educational differences in the retirement life course. With respect to the heterogeneity of work and retirement experiences, this study finds that the retirement life course of men and women differs substantially. Despite their longer life spans, women are expected to have shorter working life expectancies but live in a non-working state longer, resulting in a substantially higher proportion of non-working state in their lives. In terms of educational differences, this study finds that there is little difference in the expected length of stay in the labor force across educational levels but that poorly educated persons are more likely to spend a greater proportion of their lives in the labor force due to their shorter non-working life expectancies.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.9
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• pp.978-988
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• 2005

A three-dimensional dynamic model was applied to Lake Paldang, Han River in this study. The model was calibrated and verified using the data measured under different ambient conditions. The model results were in reasonable agreements with the field measurements in both calibration and verification. Utilizing the validated model, we analyzed the spatial and temporal distributions of temperature, current, residence time, and spreading pattern of incoming flows within the lake. Relatively low velocity and high temperature were computed at the surface layer in the southern region of the Sonae island. The longest residence time within the lake was predicted in the southern region of the Sonae island and the downstream region of the South Branch. This can be attributed to the fact that the back currents caused by the dam blocking occur mainly in these regions. Vertical thermal profiles indicated that the thermal stratifications would be occurred feebly in early summer and winter. During early spring and fall, it appeared that there would be no discernible differences at the vertical temperature profiles in the entire lake. The vertical overturns, however, do not occur during these periods due to an influence of high discharge flows from the dam. During midsummer monsoon season with high precipitation, the thermal stratification was disrupted by high incoming flow rates and discharges from the dam and very short residence time was resulted in the entire lake. In this circulation patterns, the plume of the Kyoungan stream with smallest flow rate and higher water temperature tends to travel downstream horizontally along the eastern shore of the south island and vertically at the top surface layer. The model results suggest that the Paldang lake should be a highly hydrodynamic water body with large spatial and temporal variations.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.265-266
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• 2003

유해대기오염물질 (HAPs)은 그간 비기준 오염물질로 분류되어 관심이 소홀했었지만, 독성, 발암성, 생체 축적과 대기중 지속성, 확산 등의 특성으로 인해 대기 중에 오랜 기간 체류하면서 오존 또는 광화학 산화물 등 2차 오염물질을 생성하고 악취의 원인 물질로도 작용하며 미량으로 건강과 환경에 악영향을 미칠 수 있어 그 중요성이 커지고 있다. 국내에서는 현재까지 환경기준항목을 중심으로 한 규제대상 물질에 대하여 배출원 조사와 배출계수 도출을 위한 기초 연구 등에 주안점을 두어 왔다. 그러나 실제적으로 인체에 미치는 영향을 감안한다면 유해대기오염물질(국내에서는 주로 특정대기유해물질로 규정되어 있음)에 의한 위해도는 매우 중요한 역할을 한다고 판단된다. (중략)

• 한국생물공학회:학술대회논문집
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• 2003.04a
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• pp.363-366
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• 2003

본 연구는 membrane bioreactor (MBR)을 질산화 위주로 운영하면서 질소폐수 처리 과정에서 나타나는 MBR의 운전특성 및 처리효율을 검토하고, 아울러 경제적인 질소처리 방법인 아질산화를 유도하기 위한 조건을 탐색하는 것이다. 반응기의 유효부피 8 L, 체류시간을 12시간으로 고정하고 유입폐수 중의 암모니아 농도를 증가시키는 방법으로 암모니아 부하를 $2\;kg/m^3{\cdot}day$까지 증가시켜 보았다. 운전 중반부에 이유를 명확히 알 수 없는 슬러지의 활성 저하 기간을 제외하고는 거의 98% 이상의 질산화 효율을 나타냈으며, 2 kg 이상의 암모니아 부하에서는 효율이 감소하였다. pH 조절, 유입수의 암모니아 농도 및 부하 조절에 의해 MBR 내의 free ammonia (FA) 농도를 변화시켜, FA 저해에 의한 유도한 아질산화는 매우 불안정하게 이루어졌다. 반면에, 공기 공급량을 변화시켜 반응기 내의 DO를 낮추는 방법으로 유도한 아질산 축적은 안정적인 경향을 보여 MBR에서 적절한 운전전략으로 판단된다.