• Title/Summary/Keyword: time dominated data

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Community Type and Stand Structure of the Korean Pine(Pinus koraiensis) Natural Forest in Seoraksan National Park (설악산 국립공원 잣나무 천연림의 군락유형 및 임분구조)

  • Song, Youn-Hee;Yun, Chung-Weon
    • Korean Journal of Environment and Ecology
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    • v.20 no.1
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    • pp.29-40
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    • 2006
  • This study was conducted to obtain the fundamental data for the ecological management in the Pinus koraiensis natural forest in Seoraksan National Park. The community types of the P. koraiensis forest were divided into Ainsliaea acerifolia group and Rhododendron schlippenbachii group. A. acerifolia group was subdivided into Acer tschonoskii var. rubripes subgroup and Calamagrostis arundinacea subgroup. The importance value of major species showed higher value in the order like Pinus koraienses, Abies nephrolepis, Acer barbinerve, Betula ermani, Acer pseudo-sieboldianum, Sorbus commixta and Quercus mongolica. The value of species diversify ranged from 0.44 to 0.86, and showed stronger competition in the interspecific association than in the intraspecific one. The number of individuals of P. koraiensis below 10 centimeters in the 15 study sites was 35, and it was considered that the population of P. koraiensis could be succeeded to the other species in the present situation because of lower frequency in the low layer though the canopy of tree layer was dominated with P. koraiensis. The radial growth patterns of P. koraiensis individuals were mainly fluctuated for the entire life time, which was considered to be caused by frequent disturbance.

Phytoplankton Ecosystems at Oil Spill Coasts Including the Hebei Spirit Oil Spill Site Near Taeanhaean National Park, Korea 1. Interannual Variability of Phytoplankton Community in Summer (태안해안국립공원 인근의 허베이스피리트 사고를 포함한 유류유출 해역의 식물플랑크톤 생태계 1. 하계 식물플랑크톤 군집의 연변동)

  • Yih, Wonho;Kim, Hyung Seop;Jo, Soo-Gun
    • Ocean and Polar Research
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    • v.41 no.1
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    • pp.1-10
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    • 2019
  • Right after the 2007 Hebei Spirit Oil Spill phytoplankton ecosystems were investigated for 11 years based on the seasonal monitoring of the composition and abundance of phytoplankton species. Comparable time-series data from the 1989 Exxon Valdez or the 2010 Deepwater Horizon Oil Spill sites were not available. It was suggested that the ecological healthiness of phytoplankton ecosystems at EVOS sites had recovered after 10 years following the oil spill based on chlorophyll concentrations even though these concentrations only represented phytoplankton communities in most cases. Chlorophyll concentrations can only reflect limited aspects of highly complex phytoplankton ecosystems. During the last 11 years following the 2017 HSOS, extreme variabilities were met in the seasonally averaged ratios of diatoms to phototrophic flagellates including dinoflagellates based on the microscopic cell countings. Summer phytoplankton communities exhibited some cyclic interannual changes in dominant groups every 2-4 years. During the early years (2008-2010) cryptophytes or raphidophytes (Chattonella spp.) dominated alternately each year, which was repeated again in 2014, 2015 and 2017. Two thecate dinoflagellates, Tripos fusus and Tripos furca, together accounted for 52.5% and 50.0% of all organisms in the summers of 2011 and 2012, respectively, which was repeated again in 2018. Summer occurrence and dominance by the phototrophic flagellates including HABs (Harmful Algal Blooms) species as well as their interannual variabilities in the oil spill sites could be utilized as markers for the stable and long-term management of healthy ecosystems. For this type of scientific ecosystem management monitoring of chlorophyll concentrations may sometimes be insufficient to gain a proper and comprehensive understanding of phytoplankton communities located in areas where oil spills have occurred and harmed the ecosystem.

Preliminary numerical study on hydrogen distribution characteristics in the process that flow regime transits from jet to buoyancy plume in time and space

  • Wang, Di;Tong, Lili;Liu, Luguo;Cao, Xuewu;Zou, Zhiqiang;Wu, Lingjun;Jiang, Xiaowei
    • Nuclear Engineering and Technology
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    • v.51 no.6
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    • pp.1514-1524
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    • 2019
  • Hydrogen-steam gas mixture may be injected into containment with flow regime varying both spatially and transiently due to wall effect and pressure difference between primary loop and containment in severe accidents induced by loss of coolant accident. Preliminary CFD analysis is conducted to gain information about the helium flow regime transition process from jet to buoyancy plume for forthcoming experimental study. Physical models of impinging jet and wall condensation are validated using separated effect experimental data, firstly. Then helium transportation is analyzed with the effect of jet momentum, buoyancy and wall cooling discussed. Result shows that helium distribution is totally dominated by impinging jet in the beginning, high concentration appears near gas source and wall where jet momentum is strong. With the jet weakening, stable light gas layer without recirculating eddy is established by buoyancy. Transient reversed helium distribution appears due to natural convection resulted from wall cooling, which delays the stratification. It is necessary to concern about hydrogen accumulation in lower space under the containment external cooling strategy. From the perspective of experiment design, measurement point should be set at the height of connecting pipe and near the wall for stratification stability criterion and impinging jet modelling validation.

A Study on Comparison of Changes in Ecological Characteristics for Bulgwangcheon(stream) Close-to Nature Section (불광천 자연형 하천 정비구간의 생태적 특성 변화 비교 연구)

  • Park, Won-Zei;Lee, Kyong-Jae;Han, Bong-Ho;Jang, Jae-Hoon
    • Journal of the Korean Institute of Landscape Architecture
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    • v.40 no.2
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    • pp.112-129
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    • 2012
  • The aim of this study was to provide basic data in managing the project that was carried out on Bulgwangcheon in a nature-friendly way to improve the conditions around the areas, which was brought to completion in 2002, based on changes in ecological characteristics. For this propose, this study examined documents related to the project, compared physical and enviromnental changes before and after the project was conducted and analyzed changes in the stream ecosystem. The result showed that in areas that effluent water was often observed, especially when it rained, the river wall was washed away and vegetation was found damaged. As for actual vegetation, this study compared planting coverage of each section of the research area and actual vegetation charts. The results indicated that Lespedeza spp., Aster koraiensis among mixed seeds that were planted in the reservoir path were almost swept away while Festuca arundinacea dominated the areas. Phragmites communis, Miscanthus sacchariflorns and Salix gracilistyla which had been planted in a small number were also almost washed out though a small number of them were left to form a colony. After examining the topography and structure of the plant community, this study found that areas where mixed seed were planted had changed into two types of vegetation: First type of area is dominated by P and R which are usually raised in apron with abundant floating particles. The second type of area is dominated by dry gramineous plant such as F and A. Areas around low flow channel where Phragmites communis, Miscanthus sacchariflorus and Salix gracilistyla planting construction method is applied was washed away with the width of low flow channel reduced. Though P, M and S formed a small community in some areas around the low flow area, they were in small number and in composition of simple plant species. Two ways were suggested in this study to manage the stream in an ecological way. First, adequate revetment construction methods should be applied by monitoring the flow of the stream as well as considering the flood control of urban streams. Second, target vegetation communities that are suitable for the environment of the stream should be chosen and be plantedconstantly with high density. At the same time, ornamental native plants shouldn't be planted as they have been and disturbing vegetation should be removed.

Estimating the Spatial Distribution of Rumex acetosella L. on Hill Pasture using UAV Monitoring System and Digital Camera (무인기와 디지털카메라를 이용한 산지초지에서의 애기수영 분포도 제작)

  • Lee, Hyo-Jin;Lee, Hyowon;Go, Han Jong
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.36 no.4
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    • pp.365-369
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    • 2016
  • Red sorrel (Rumex acetosella L.), as one of exotic weeds in Korea, was dominated in grassland and reduced the quality of forage. Improving current pasture productivity by precision management requires practical tools to collect site-specific pasture weed data. Recent development in unmanned aerial vehicle (UAV) technology has offered cost effective and real time applications for site-specific data collection. To map red sorrel on a hill pasture, we tested the potential use of an UAV system with digital cameras (visible and near-infrared (NIR) camera). Field measurements were conducted on grazing hill pasture at Hanwoo Improvement Office, Seosan City, Chungcheongnam-do Province, Korea on May 17, 2014. Plant samples were obtained at 20 sites. An UAV system was used to obtain aerial photos from a height of approximately 50 m (approximately 30 cm spatial resolution). Normalized digital number values of Red, Green, Blue, and NIR channels were extracted from aerial photos. Multiple linear regression analysis results showed that the correlation coefficient between Rumex content and 4 bands of UAV image was 0.96 with root mean square error of 9.3. Therefore, UAV monitoring system can be a quick and cost effective tool to obtain spatial distribution of red sorrel data for precision management of hilly grazing pasture.

A Study on the Causes of Elderly Crime and Its Countermeasures in the Transition of Elderly Society (초고령사회 전환기에 노인범죄 발생원인과 그 대책에 관한 연구)

  • Yang, Jae Yeol;Kim, Sang Su;Lee, Ju Yeon
    • Korean Security Journal
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    • no.61
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    • pp.307-332
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    • 2019
  • Recently, our society has been changing its population structure due to low birth rate along with the extension of life span due to the development of medical environment and improvement of living environment. It was not long before the population became older, and the problem of the elderly was amplified by generational conflict. The current generation of senior citizens could not afford to prepare for their own retirement income due to their children's education, marriage and housing problems, and is a generation alienated from the benefits of public income security. In addition, not only are they in poverty with rapid industrialization, informatization and economic instability, but they are also threatened with livelihood. The increase in elderly crimes arising from the elderly, who are less adaptable to our society dominated by materialism, is being highlighted as a new social issue. In this study, we are going to analyze the causes of violent and violent senior citizens' crimes in quality along with quantitative growth, and present criminal situations and preventive measures using 10 years of data, judging that this is a time when a national response is needed through a social discussion on crimes committed by senior citizens in our society, where the pace of aging is unprecedentedly fast in the world In order to achieve this research objective, various opinions and statistical data of our society where the standards of senior citizens are changing were reviewed, and analysis of crimes was conducted on literature utilizing data of the Supreme Public Prosecutor's Office, the National Police Agency, and the National Statistical Office, recent press releases, and existing research materials. In this study, we will diagnose crimes committed by senior citizens in various aspects, including the characteristics of the elderly and the view of the elderly in the present society, and explore the direction of development for the prevention of future crimes as well.

Modeling Residual Water in the Gas Diffusion Layer of a Polymer Electrolyte Membrane Fuel Cell and Analyzing Performance Changes (고분자 전해질막 연료전지의 기체확산층 내부 잔류수 모델링 및 성능변화해석)

  • Jiwon Jang;Junbom Kim
    • Applied Chemistry for Engineering
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    • v.35 no.1
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    • pp.16-22
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    • 2024
  • Polymer electrolyte membrane fuel cells have the advantage of low operating temperatures and fast startup and response characteristics compared to others. Simulation studies are actively researched because their cost and time benefits. In this study, the resistance of water residual in the gas diffusion layer (GDL) of the unit cell was added to the existing equation to compare the actual data with the model data. The experiments were conducted with a 25 cm2 unit cell, and the samples were separated into stopping times of 0, 10, and 60 minutes following primary impedance measurement, activation, and polarization curve data acquisition. This gives 0, 10, and 60 minutes for the residual water in the GDL to evaporate. Without the rest period, the magnitude of the performance improvement was not significantly different at the same potential and flow rate, but the rest period did improve the performance of the membrane electrode assembly when measuring impedance. By changing the magnitude of the resistance reduction to an overvoltage, the voltage difference between the fuel cell model with and without residual water was compared, and the error rate in the high current density region, which is dominated by concentration losses, was reduced.

Anomaly Detection for User Action with Generative Adversarial Networks (적대적 생성 모델을 활용한 사용자 행위 이상 탐지 방법)

  • Choi, Nam woong;Kim, Wooju
    • Journal of Intelligence and Information Systems
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    • v.25 no.3
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    • pp.43-62
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    • 2019
  • At one time, the anomaly detection sector dominated the method of determining whether there was an abnormality based on the statistics derived from specific data. This methodology was possible because the dimension of the data was simple in the past, so the classical statistical method could work effectively. However, as the characteristics of data have changed complexly in the era of big data, it has become more difficult to accurately analyze and predict the data that occurs throughout the industry in the conventional way. Therefore, SVM and Decision Tree based supervised learning algorithms were used. However, there is peculiarity that supervised learning based model can only accurately predict the test data, when the number of classes is equal to the number of normal classes and most of the data generated in the industry has unbalanced data class. Therefore, the predicted results are not always valid when supervised learning model is applied. In order to overcome these drawbacks, many studies now use the unsupervised learning-based model that is not influenced by class distribution, such as autoencoder or generative adversarial networks. In this paper, we propose a method to detect anomalies using generative adversarial networks. AnoGAN, introduced in the study of Thomas et al (2017), is a classification model that performs abnormal detection of medical images. It was composed of a Convolution Neural Net and was used in the field of detection. On the other hand, sequencing data abnormality detection using generative adversarial network is a lack of research papers compared to image data. Of course, in Li et al (2018), a study by Li et al (LSTM), a type of recurrent neural network, has proposed a model to classify the abnormities of numerical sequence data, but it has not been used for categorical sequence data, as well as feature matching method applied by salans et al.(2016). So it suggests that there are a number of studies to be tried on in the ideal classification of sequence data through a generative adversarial Network. In order to learn the sequence data, the structure of the generative adversarial networks is composed of LSTM, and the 2 stacked-LSTM of the generator is composed of 32-dim hidden unit layers and 64-dim hidden unit layers. The LSTM of the discriminator consists of 64-dim hidden unit layer were used. In the process of deriving abnormal scores from existing paper of Anomaly Detection for Sequence data, entropy values of probability of actual data are used in the process of deriving abnormal scores. but in this paper, as mentioned earlier, abnormal scores have been derived by using feature matching techniques. In addition, the process of optimizing latent variables was designed with LSTM to improve model performance. The modified form of generative adversarial model was more accurate in all experiments than the autoencoder in terms of precision and was approximately 7% higher in accuracy. In terms of Robustness, Generative adversarial networks also performed better than autoencoder. Because generative adversarial networks can learn data distribution from real categorical sequence data, Unaffected by a single normal data. But autoencoder is not. Result of Robustness test showed that he accuracy of the autocoder was 92%, the accuracy of the hostile neural network was 96%, and in terms of sensitivity, the autocoder was 40% and the hostile neural network was 51%. In this paper, experiments have also been conducted to show how much performance changes due to differences in the optimization structure of potential variables. As a result, the level of 1% was improved in terms of sensitivity. These results suggest that it presented a new perspective on optimizing latent variable that were relatively insignificant.

A study on the awareness of snack intake preference actual conditions and oral health education for business world man high school locating in Kyonggi province (경기지역 실업계 남자고등학생의 간식선호도 실태와 구강보건교육 인식도에 관한 조사연구)

  • Choi, Yun-Hwa;Jee, Yun-Jeong
    • Journal of Korean society of Dental Hygiene
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    • v.8 no.2
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    • pp.93-106
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    • 2008
  • This study is to enforce to ready basic data of effective school dental health education for dental caries prevention, relation knowledge of class, feeding practice and snack intake preference actual conditions, food and caries executed investigation by own recording way using questionnaire consisted of dental health education awareness to some business world man high school locating in Kyonggi Province. Analyzes result that total 487 people respond in SPSS WIN 13.0 programs and got following sequence The obtain result were as follows 1. Results about habit of breakfast was the most by 36.1% a student who have breakfast every day, and a student who hardly eat dominated 32.9%. Second-year student hardly had breakfast (p<.01). 2. A student who answer that snack kind that often eat was cookies and snack kind was the most by 37.2%, and a student who answer that symbol drink was a carbonated drink was the most by 50.9%. 3. Relation knowledge degree appeared grand mean among 18 points perfect score by 12.36 with food and caries. Third-year student knowledge degree was the highest, and second-year student was the lowest knowledge degree by class (p<.01). 4. Existence and nonexistence of experience of dental health education appeared a student who experience that take dental health education does not exist by 57.1%. There was experience that take dental health education as class is low by class, and as class is high, experience did not exists (p<.05). 5. Time that take dental health education for the first time was the most by 56.7% a student who respond 'Babyhood', grade in school is low by class 'Babyhood', and is high by class responded 'Middle school'(p<.05). 6. Awareness of dental health education necessity 'may educate dental health and does not' a student 56.3%, half was looked attitude which students who exceed are insincere about dental health education necessity. 7. When educate dental health, contents was the most by 44.6% 'brushing and mouth article directions' to be educated importantly, and was expose by caries 31.2%, gum disease 10.1%, scaling 9.0%, prosthetic dentistry and implant 5.1% period of ten days, third-year student 50.8% said that 'brushing and mouth article directions' is important (p<.05). Dental health education is practiced during life, and is a teaching that should be remembered. Need to develop epoch-making and interesting education program that is correct in subject to do as quickly as possible, and should be achieved major road of dental hygienist. Dental hygienist will have to settle as quickly as possible as expert of prevention that is natural business and education and help in dental health education development under effort between country and dental association effective.

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Influences of Coastal Upwelling and Time Lag on Primary Production in Offshore Waters of Ulleungdo-Dokdo during Spring 2016 (2016년 춘계 울릉도-독도주변해역에서 동해 연안 용승과 시간차에 의한 일차생산력 영향)

  • Baek, Seung Ho;Kim, Yun-Bae
    • Korean Journal of Environmental Biology
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    • v.36 no.2
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    • pp.156-164
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    • 2018
  • In order to investigate the upwelling and island effects following the wind storm events in the East Sea (i.e., Uljin-Ulleungdo-Dokdo line) during spring, we assessed the vertical and horizontal profiles of abiotic and biotic factors, including phytoplankton communities. The assessment was based on the Geostationary Ocean Color Imager (GOCI) and field survey data. A strong south wind occurred on May 3, when the lowest sea level pressure (987.3 hPa) in 2016 was observed. Interestingly, after this event, huge blooms of phytoplankton were observed on May 12 along the East Korean Warm Current (EKWC), including the in the offshore waters of Ulleungdo and Dokdo. Although the diatoms dominated the EKWC area between the Uljin coastal waters and Ulleungdo, the population density of raphidophytes Heterosigma akashiwo was high in the offshore waters of Ulleungdo-Dokdo. Based on the vertical profiles of Chlorophyll-a (Chl. a), the sub-surface Chl. a maximum appeared at 20 m depths between Uljin and Ulluengdo, whereas relatively high Chl. a was distributed equally across the entire water column around the waters of Ulleungdo and Dokdo islands. This implies that the water mixing (i.e., upwelling) at the two islands, that occurred after the strong wind event, may have brought the rapid proliferation of autotrophic algae, with nutrient input, to the euphotic layer. Therefore, we have demonstrated that a strong south wind caused the upwelling event around the south-eastern Korean peninsula, which is one of the most important role in occurring the spring phytoplankton blooms along the EKWC. In addition, the phytoplankton blooms may have potentially influenced the oligotrophic waters with discrete time lags in the vicinity of Ulleungdo and Dokdo. This indicates that the phytoplankton community structure in the offshore waters of Ulleungdo-Dokdo is dependent upon the complicated water masses moving related to meandering of the EKWC.