• Journal of Ecology and Environment
• /
• 제47권2호
• /
• pp.49-62
• /
• 2023

Background: Over the past three decades, gradual eustatic sea-level rise has been considered a primary exogenous factor in the increased frequency of flooding and biological changes in several salt marshes. Under this paradigm, the potential importance of short-term events, such as ocean storminess, in coastal hydrology and ecology is underrepresented in the literature. In this study, a simulation was developed to evaluate the influence of wind waves driven by atmospheric oscillations on sedimentary and vegetation dynamics at the Skallingen salt marsh in southwestern Denmark. The model was built based on long-term data of mean sea level, sediment accretion, and plant species composition collected at the Skallingen salt marsh from 1933-2006. In the model, the submergence frequency (number yr^-1) was estimated as a combined function of wind-driven high water level (HWL) events (> 80 cm Danish Ordnance Datum) affected by the North Atlantic Oscillation (NAO) and changes in surface elevation (cm yr^-1). Vegetation dynamics were represented as transitions between successional stages controlled by flooding effects. Two types of simulations were performed: (1) baseline modeling, which assumed no effect of wind-driven sea-level change, and (2) experimental modeling, which considered both normal tidal activity and wind-driven sea-level change. Results: Experimental modeling successfully represented the patterns of vegetation change observed in the field. It realistically simulated a retarded or retrogressive successional state dominated by early- to mid-successional species, despite a continuous increase in surface elevation at Skallingen. This situation is believed to be caused by an increase in extreme HWL events that cannot occur without meteorological ocean storms. In contrast, baseline modeling showed progressive succession towards the predominance of late-successional species, which was not the then-current state in the marsh. Conclusions: These findings support the hypothesis that variations in the NAO index toward its positive phase have increased storminess and wind tides on the North Sea surface (especially since the 1980s). This led to an increased frequency and duration of submergence and delayed ecological succession. Researchers should therefore employ a multitemporal perspective, recognizing the importance of short-term sea-level changes nested within long-term gradual trends.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2021년도 춘계학술대회
• /
• pp.189-192
• /
• 2021

항적추적 기술에 딥러닝 기반 LSTM(Long Short-Term Memory) 모델을 적용하는 연구로서 기존의 항적추적기술의 경우, 항공기의 등속, 등가속, 급기동, 선회(3D) 비행 등 비행 특성에 따른 칼만 필터 기반의 LMIPDA를 활용한 실시간 항적 추적 시 등속, 등가속, 급기동, 선회(3D) 비행 가중치가 자동으로 변경된다. 이러한 과정에서 등속 비행 중 급기동 비행과 같이 비행 특성이 변경될 때, 항적 손실 및 항적 추적 성능이 하락하여 비행 특성 가중치 변경성능을 향상시킬 필요성이 있다. 본 연구는 레이더의 오차 모델이 적용된 시뮬레이터의 Plot과 표적을 딥러닝 기반 LSTM(Long Short-Term Memory) 모델을 적용하여 학습시키고, 칼만 필터를 활용한 항적추적 결과와 딥러닝 기반 LSTM(Long Short-Term Memory) 모델을 적용한 항적추적결과를 비교함으로써 미리 비행 특성의 변경과정을 예측하여 등속, 등가속, 급기동, 선회(3D) 비행 가중치변경을 신속하게 함으로써 항적추적성능을 향상하기 위한 연구이다.

• Geomechanics and Engineering
• /
• 제10권5호
• /
• pp.565-575
• /
• 2016

Geosynthetics reinforced soil (GRS) walls constructed on weak grounds may change in both the horizontal earth pressure and deformation on wall facing. However, only few studies were done in the literature to measure and analyze the horizontal external deformation behavior of GRS walls constructed on soft grounds for a long period of time. The present study describes the external deformation behavior of GRS walls observed for 12-year long-term performance. The horizontal deformation of the geosynthetics-wrapped-facing GRS walls shows a passive behavior along one third of the wall height, from top going downwards, and active behavior for the rest of the wall height. Even if the geogrid and nonwoven geotextiles are exposed directly to sunlight and rainfalls in a span of 12 years, they have functioned well as wall facing. Therefore, the geosynthetic reinforcement material is strong enough to resist ultraviolet rays.

• 한국조경학회지
• /
• 제44권5호
• /
• pp.81-91
• /
• 2016

이 연구는 장기미집행 도시공원의 해소와 활성화 방안으로 특례사업제도가 도입되었다. 민간공원추진자의 원활한 사업추진을 도모할 수 있도록 사업성 분석을 실시하여 특례사업 적용이 가능한지를 살펴보고자 하였다. 광주광역시 장기미집행 도시공원 3개소를 대상으로 사업성을 분석한 결과는 다음과 같다. 첫째, 분석대상의 광주광역시 장기미집행 3개소의 도시공원은 산림형 근린공원으로서, 특례사업의 공원조성비(평균 0.4%)가 차지하는 비율은 상대적으로 낮으나, 토지보상비(평균 33.8%)와 건물공사비(평균 59.1%)의 지출에 의해 사업수지에 많은 영향을 받는다. 둘째, 장기미집행 도시공원의 특례사업이 대규모 공원면적의 토지보상비와 건물공사비의 초기투입비가 과다하고, 장기간(5년 이상)에 걸친 회수 및 금융이자 등 시간의 경과를 감안하여 단순 비용편익보다는 순현가(NPV)를 적용하여 사업수지를 검토한 결과, 봉산공원은 순현가 기준 사업수지 균형 용적률은 179%, 적정이익 용적률은 220% 수준이며, 마륵공원은 균형 용적률 351%, 적정이익 용적률은 420%, 중외공원은 균형 용적률 327%, 적정이익 용적률은 400%이다. 셋째, 장기미집행 도시공원이 실효되기 전에 특례사업의 원활한 추진을 위해서는 광주광역시 도시계획위원회의 심의 시 비공원시설부지의 용도지역이 자연녹지지역에서 봉산공원은 제2종일반주거지역으로, 중외공원은 준주거지역으로의, 마륵공원은 일반상업지역으로 용도지역 변경이 이루어져야 민간공원추진자의 사업성 개선으로 사업추진이 가능한 것으로 나타났다.

• 한국식생활문화학회지
• /
• 제16권5호
• /
• pp.431-441
• /
• 2001

To develop the low-temperature and long-term fermented kimchi, kimchi was prepared according to the recipe of a specific ratio of major and minor ingredients and adjusted its salinity to 3.7%. Prepared kimchi fermented at $15{\pm}1^{\circ}C$ for 24 hours and transferred and fermented in a refrigerator only used to make low-temperature and long-term fermented kimchi at $-1{\pm}1^{\circ}C$ for 30 weeks. During 30 weeks of fermentation the changes in physicochemical and microbiological properties of low-temperature and long-term fermented kimchi were studied. The initial pH of 6.47 decrease gradually and dropped to pH 4.0 after 14 weeks of fermentation, and then it maintained at same level. Acidity increased to 0.49% on 2 weeks of fermentation and kept at 0.47 $\sim$0.50% during 2 to 30 weeks fermentation. Salinity was slightly increased at early stage and started to decrease on 4 weeks of fermentation, and then it did not change. The change of reducing sugar content was closely related to the trend of pH change with a very high correlation coefficient(r =0.912). Lactic acid, citric acid, malic acid, succinic acid and acetic acid were major organic acids contained in low-temperature and long-term fermented kimchi. Vitamin C content decreased at initial stage of fermentation and then slightly increased up to the maximum of 22.3 mg% on 8weeks of fermentation. In color measurement, L value continued to increase during the fermentation and reached at the highest of 55.45 on 22 weeks of fermentation, and a and b values of 3.62 and 4.54 also increased to 31.26 and 37.32 on 30 weeks of fermentation, respectively. Total microbial count increased slowly from beginning and was the highest on 4 weeks of fermentation, and then began to decrease slowly. Count of Lactobacillus spp. was highest after 6weeks, but count of Lactobacillus spp. was highest on 2 weeks of fermentation, and then both showed a slow decrease. Yeast count wasn't increased until 4 weeks of fermentation and then increased rapidly to get the highest on 10 weeks of fermentation.

• 산경연구논집
• /
• 제9권10호
• /
• pp.39-50
• /
• 2018

Purpose - This study is to propose discriminative management strategies to long-term care facilities based on the empirical analysis after reviewing the effects of social support, perceived by long-term care facility employees, to service orientation. Research design, data, and Methodology - The research model designed social support, job stress, organizational commitment, and service orientation. The survey collected data from 453 customers in a long-term care facility in jeju. The SPSS 18.0 package was used for analysis. Results - First, social support for long-term care facility employees has a negative(-) effect to job stress. Test results, social support factors except appraisal support had a negative impact on job stress. Second, social support has a positive(+) effect to organizational commitment. Test results, informational support, tangible support and appraisal support had significant effects on organizational commitment. However, emotional support had a positive impact on affective commitment and normative commitment. Third, social support has a positive(+) effect to service orientation. Test results had a positive impact. Fourth, job stress has a negative(-) effect to organizational commitment. In the test results, employee's continuance commitment and normative commitment had significant negative effects in job stress. However, affective commitment had no significant impact. Fifth, job stress has a negative(-) effect to service orientation. Test results showed a negative impact. Conclusions - The study implies the following. First, that there should be a change in the social perception of long-term care facilities. 'Long-Term Care Insurance for The Elderly' was enacted to emphasize this responsibility for the elderly problems as a new system. Enactment of this Act was expected to improve the quality of life of the people by stabilizing the elderly life and reducing the burden of families. Therefore, long-term care facility system should be as efficient as possible for making plans for systematic and organizational support. Second, the efforts of facility managers to minimize job stress of employees is necessary. Accordingly, performing spontaneous work is required for a comfortable working environment and management. Third, the systematic education and training to employees for service oriented behavior of the facility will be required in the long term.

• 콘크리트학회논문집
• /
• 제12권4호
• /
• pp.69-78
• /
• 2000

Creep of concrete is the most dominating factor affecting time-dependent deformations of concrete structures. Especially, creep deformation for design and construction in prestressed concrete structures should be predicted accurately because of its close relation with the loss in prestree of prestressed concrete structures. Existing creep-prediction models for special applications contain several impractical factors such as the lack ok accuracy, the requirement of long-term test and the lack of versatility for change in material properties, ets., which should be improved. In order to improve those drawbacks, a methodology to modify the creep-prediction equation specified in current Korean concrete structures design standard (KCI-99), which underestimates creep of concrete and does not consider change of condition in mixture design, is proposed. In this study, short-term creep tests were carried out for early-age concrete within 28 days after loading and their test results on influencing factors in the equation are analysed. Then, the prediction equation was modified by using the early-age creep test results. The modified prediction equation was verified by comparing their results with results obtained from long-term creep test.

• 한국제4기학회지
• /
• 제19권2호
• /
• pp.44-44
• /
• 2005

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 2001년도 춘계학술발표회요약집
• /
• pp.522.2-522
• /
• 2001

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2001년도 학술발표회 논문집(II)
• /
• pp.721-726
• /
• 2001