• Journal of Korean Society of Environmental Engineers
• /
• v.34 no.6
• /
• pp.421-429
• /
• 2012

This study was aimed to analyze the water quality characteristics of the Hwapocheon Stream and to be utilized in the further related research. Water in the upper stream became a dammed pool due to the existence of 14 weirs, and pollutants such as both sewage and irrigation water were introduced into the mainstream passing through farming settlements and agricultural land. For these reasons, filamentous cyanobacteria (Oscillatoria sp.) bloomed at the bottom of the dammed pool. Also in the midstream and downstream, tributaries with high pollutant concentrations [e.g., Comocheon (T3) and Yongdeokcheon (T8)] were inflowed, and had a negative impact on water quality of the mainstream, especially nitrogen and phosphorus. In the Hwapocheon Stream, dissolved oxygen (DO) decreased, and suspended solid (SS) increased toward the downstream. The result showed that hydraulic retention time, SS, COD, and concentration of $NH_4{^+}$ were important water quality factors of the Hwapocheon Stream. The high concentration of benthic organic matter and rich in attached algae in the core of Hwapo-wetland were expected to give impact on the water quality of the mainstream. In the spatial manner, water quality showed increasing trend in the weir zone, and it was constant or decreased trend in wetland. In the seasonal manner, the nutrient concentrations were high in the winter dry season, however, the organic matter concentrations were high in spring and summer. Generally, the concentrations of phytoplankton value were $40{\mu}g\;chl-{\alpha}/L$ or less in all reaches except for the high concentrations in the weir and wetland area in June.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.19 no.5
• /
• pp.119-137
• /
• 2020

Over the last two decades, the attitudes to cars have changed from buying a car to sharing a car, especially among young people. Shared transport services and autonomous vehicles together can resolve the accessibility issue of shared transport services. Furthermore, they will make it possible to develop a new model of apartments without car parking. Therefore, the study estimated the demand for car sharing by young people and the running efficiency of car-sharing dealing with their car-based trip demand. The study chose nine apartment complexes for study sites where a majority of the residents were young people. The questionnaire survey was conducted to collect data on the trip demands of young people. The results showed that there are significant differences in the car-sharing use patterns and demand between the apartment houses located in the Capital region and non-capital region. Young people living in apartments in the Capital region used car sharing once per day per person for approximately 80 minutes per trip and tended to hire that between 8 AM and 10 AM. On the other hand, the young people living in apartments in the non-capital region used car sharing twice per day per person for approximately 200 minutes per trip. They tended to hire that frequently in the afternoon and evening as well as in the morning. The results also showed that a single car-sharing vehicle could deal with 3~4 trips per day in the Capital region and around 2 trips per day in the non-capital region.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.6 no.3
• /
• pp.151-161
• /
• 2003

The spatiotemporal distribution of resuspended solid on the shelf of the southern Yellow Sea and the northern East China Sea was studied. The sea surface reflectance imageries obtained by remote sensing using satellite at channels of red (620~670nm), green(545~565nm) and blue(459~479nm) from Terra MODIS were used to explain the front of the high concentration suspended solid(SS) on the shelf in the East China Sea. The horizontal distribution of the resuspended solid was depended on the wind force, tidal current and stratification of water. The horizontal distribution areas of the resuspended solid in winter season during January~April, 2002 were three times wider than those in summer season during June~September, 2001.

• Journal of the Korean Electrochemical Society
• /
• v.3 no.3
• /
• pp.146-151
• /
• 2000

So fine cobalt oxide xerogel powders were prepared by using a unique solution chemistry associated with the sol-gel process. The effect of thermal treatment on the crystalinity, particle structure, and corresponding electrochemical properties of the resulting xerogel remained amorphous as $Co(OH)_2$ up to $160^{\circ}C$ With an increase in the temperature above $200^{\circ}C$, both the surface area and pore volume decreased sharply, because the amorphous $Co(OH)_2$ decomposed to form CoO that was subsequently oxidized to form crystalline Co304. In addition, the changes in the crystallinity, and particle structure all had significant but coupled effects on the electrochemical properties of the xerogels. A maximum capacitance of 192F1g was obtained for an electrode prepared with the $CoO_x$ Xerogel calcined at$150^{\circ}C$, which was consistent with the maxima exhibited in both the surface area and pore volume. This capacitance was attributed solely to a surface redox mechanism.

• Journal of Periodontal and Implant Science
• /
• v.31 no.3
• /
• pp.543-554
• /
• 2001

치주조직 재생을 도모하기 위한 전통적인 시술방법으로 여러가지 골이식재를 이용한 골이식술이 이용되고 있다. 이번 실험의 목적은 골형성을 위한 재료로 Calcium Polyphosphate(CPP)를 사용하여 비글견에서의 조직 반응과 골유도성을 보는 것이고 또한 다른 이식재들간에 신생골의 형성에 어느정도 영향을 주는 가를 알아보는 것이다. 이번 실험에 사용된 CPP는 무수 $Ca(H_2PO_4)$를 condensation하여 무결정의 $Ca(PO_3)_2$를 얻고 이를 용율하고 냉각시킨 후 분쇄하여 얻은 것으로 3세된 비글견에 이식하여 관찰하였다. 조직학적으로 CPP granule의 경우는 키토산이나 $Na_2O$를 넣은 경우 모두 bone 의 ingrowth가 관찰되었고 다른 섬유조직의 개재를 볼수 없었다 동결탈회건조골을 넣은 경우에는 주위로 골형성 보이지 않았고 단지 섬유성 조직이 관찰 되었다. 아무것도 넣지 않은 경우에 비해서 동결탈회건조골이나 키토산, $Na_2O$를 넣은 CPP granules 경우에 더 많은 비율로 신생 골의 양이 나타나는 것을 볼수 있었다. 아무것도 넣지 않은 대조군과 이식재를 넣은 군간에는 유의성이 있는 것으로 나타났고(p<0.05). 또한 CPP granules with chitosan과 CPP granules with $Na_2O$ 사이에는 신생골의 형성에 유의성이 없었다. 이것으로 보아 CPP granules with chitosan과 CPP granules with $Na_2O$는 모두 골유도성이 있고 신생골의 형성을 촉진하므로 치주질환으로 인한 골결손 부위에 사용할 수 있는 재료로 우수한 특성을 지닌다고 사료된다.

• Journal of Korean Society of Forest Science
• /
• v.96 no.4
• /
• pp.401-407
• /
• 2007

This study analyzed an economic efficiency of oak mushroom cultivation in order to provide data needed for formulating related policies. 88 farmhouses in major producing areas were interviewed with. The average production cost per 100 bed-logs was 151,699 won. Among production costs, material costs accounted for 56.0% and labor costs 41.8%. Oak mushroom cultivation was labor-intensive and labor input was a significant factor determining the production costs. There was 3 7.2% gap in production costs between Chungbuk, the highest cost area and Gyeonggi, the lowest cost area of oak mushroom due to difference in labor input. Average revenue per 100 bed-logs was 178,627 won. Average income per 100 bed-logs, which is variable production costs of 116,613 won subtracted from the revenue, was 62,014 won and thus income rate was 34.7%. Income rate in Jeonbuk, the highest area, was higher than that in Gyeonggi, the lowest area, by 15.8% points due to difference in quantities produced, grade, and variable production costs, in particular, labor costs. The result of the economic analysis indicates that reduction in establishment and labor costs, accounting for the highest portion in production costs is priority issue for the enhancement of the competitiveness of the oak mushroom industry.

• Korean journal of applied entomology
• /
• v.46 no.3
• /
• pp.437-444
• /
• 2007

The effect of environmental factors on the over-wintering success of the apple snail, Pomacea canaliculata, which is considered as unable to hibernate during winter climate in Korea. This study was examined to determine the location of over-wintering habitats in the agricultural water system related with weed control using the apple snail in rice paddy field in the Yeongnam district from 2003 to 2006. Over-wintering success of the apple snail was observed at Hadong, Hapchen, Sanchung, Kimhae, Milyang, Changwon, Ulsan, Busan, Gyengju, Pohang, Chilgok, Seongju, Gumi, Sangju and Youngju in Yeongnam area. And the over-wintering locations of apple snail going north year by year. Accordingly, the successful over-wintering sites observed were deep wells, water running canals and brooks not dried conditions. A special feature of this sites was that the water of this sites was not frozen during winter season.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2001.09a
• /
• pp.122-140
• /
• 2001

We have applied the geophysical survey, mainly electric and electromagnetic (EM) methods, to a test site contaminated by hydrocarbon waste disposal and local spill. The multi-frequency, moving source & receiver EM survey along with ground penetrating radar (GPR) showed a fairly good performance in detection of buried metal pipes and objects. Magnetic survey measuring vertical and horizontal gradients were so sensitive to the small metallic objects spread over the surface that it's hard to discriminate the buried pipe. We chose electrical resistivity, EM and GPR survey to examine the soil contamination. Depth slices of resistivity distribution as the results of the inversion of resistivity and EM data coincided each other and closely matched the contaminated area determined by chemical analysis of the soil samples. GPR images did not show the reflection events related with contamination plume since there are no distinct spill in this site. We inferred the contamination using the penetration depth of the GPR energy, which could be used as auxiliary information to the resistivity and EM results. We summarized the applicability of each survey methods based on this results and proposed a desirable survey scheme for the determination of hydrocarbon contaminated site.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.6C
• /
• pp.544-561
• /
• 2002

In this paper, we propose a new hybrid type of the routing protocol (Virtual Cluster-based Routing Protocol: VCRP) for mobile ad-hoc networks, based on a virtual cluster, which is defined as a narrow-sense network to exchange the basic information related to the routing among the adjacent nodes. This particular approach combines advantage of proactive routing protocol (PRP), which immediately provides the route collecting the network-wide topological and metric information, with that of reactive routing protocol, which relies on the route query packet to collect the route information on its way to the destination without exchanging any information between nodes. Furthermore, it also provides the back-up route as a byproduct, along with the optimal route, which leads to the VCBRP (Virtual Cluster-based Routing Protocol with Backup Route) establishing the alternative route immediately after a network topology is changed due to degradation of link quality and terminal mobility, Our simulation studies have shown that the proposed routing protocols are robust against dynamics of network topology while improving the performances of packet transfer delay, link failure ratio, and throughput over those of the existing routing protocols without much compromising the control overhead efficiency.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.13 no.3
• /
• pp.197-205
• /
• 2020

Korean language has the characteristics that the pronunciation of phoneme units such as vowels and consonants are fixed and the pronunciation associated with a notation does not change, so that foreign learners can approach rather easily Korean language. However, when one pronounces words, phrases, or sentences, the pronunciation changes in a manner of a wide variation and complexity at the boundaries of syllables, and the association of notation and pronunciation does not hold any more. Consequently, it is very difficult for foreign learners to study Korean standard pronunciations. Despite these difficulties, it is believed that systematic analysis of pronunciation errors for Korean words is possible according to the advantageous observations that the relationship between Korean notations and pronunciations can be described as a set of firm rules without exceptions unlike other languages including English. In this paper, we propose a visualization framework which shows the differences between standard pronunciations and erratic ones as quantitative measures on the computer screen. Previous researches only show color representation and 3D graphics of speech properties, or an animated view of changing shapes of lips and mouth cavity. Moreover, the features used in the analysis are only point data such as the average of a speech range. In this study, we propose a method which can directly use the time-series data instead of using summary or distorted data. This was realized by using the deep learning-based technique which combines Self-organizing map, variational autoencoder model, and Markov model, and we achieved a superior performance enhancement compared to the method using the point-based data.