• Journal of Marine Bioscience and Biotechnology
• /
• v.5 no.4
• /
• pp.15-25
• /
• 2011

Marine sponges are a rich source of highly diversified bioactive compounds. These medicinally valuable molecules represent extreme physiological and ecological functions in sponges, more presumably involving in the resistance to the feeding by other marine organisms like fish and fouling by barnacles, bacteria, fungi, etc. This feature of attaining resistance made sponges as successful poriferans that possess an impressive array of biological properties ranging from antimicrobial to anticancerous activities. The diversified bioactive principle of sponges might be due to their spacio-temporal distribution and although, the gateway for exploiting the sponges for isolating these distinct, potential molecules is open, suitable technical and methodological approaches are yet to be implemented in order to bring the sponges as successful pharmaceutical leads in the field of marine biotechnology. Despite of the identified difficulties of marine sponge research from past few decades, one should concentrate not only on the basic and applied technical/methodological considerations, but also on the novel strategies like in vitro sponge cell, fragment and whole sponge culture; sponge symbiont cell culture; in situ and ex situ sponge cultivation; and sponge bioreactors and metagenomic approaches, for the successful exploitation of marine sponges towards the novelty in sponge biotechnology. The present review narrates the pros and cons of the nowadays-marine sponge research by focusing on the suggestive ecobiotechnological approaches, based on the latest studies for feasible ecological exploitation and biotechnological application of sponges from the sea.

• 한국해양학회지
• /
• v.27 no.3
• /
• pp.189-196
• /
• 1992

A simple quasi-geostrophic model is considered to explain the separation of the East Korean Warm Current(EKWC) and formation of the North Korean Cold Current(NKCC). In this model, the circulation is driven by inflow-outflow condition and modified by local forcing. The solution is decomposed into inflow-outflow and local modes which describe only the effects of inflow-outflow condition and local forcing, respectively. Results of analyses show that both the surface cooling and positive wind stress curl are favorable for the separation of EKWC and formation of NKCC. This fact is compatible with the present knowledge about heat flux and wind stress field over the Sea of Japan.

• Korean Journal of Remote Sensing
• /
• v.23 no.1
• /
• pp.65-69
• /
• 2007

The processes of regional scales in the East Korean coastal waters were investigated by analysis of the Synthetic Aperture Radar (SAR) images taken by the European Research Satellites ERS-1, ERS-2 and Envisat. More than 500 quick look frames taken in 1991-2003 were examined to detect the frames with clearly surface expressions of oceanic phenomena. 26 ERS-1/2 SAR and 11 Envisat wide swath Advanced SAR (ASAR) frames were selected and obtained from the European Space Agency in a form of the precision high-resolution images. The following oceanic phenomena and processes were evident in the radar imagery through the Korean costal waters: fronts, currents, eddies, internal waves, island and ship wakes, oil pollution, etc. They manifested themselves in the field of sea surface roughness, their scale ranged from several tens meters to about 100 km. The most common morphology of these phenomena was a series of contrast dark or light curvilinear lines and bands. The joint analysis of the discussed SAR images with other satellite and in situ data supported and enhanced our interpretation of SAR signatures.

• Korean Journal of Remote Sensing
• /
• v.7 no.2
• /
• pp.113-130
• /
• 1991

Meterological satellites have taken their important place as astandard observing platform from which to measure weather. Specially, they provide a useful information about the weather of wide dessert or sea. This information is really helpful to understand the field of satellite meteorology. Several leading countries, for example, USA, EC, Russia, and Japan, launch two different satellites, both Geostationary and Polar orbiting satellite system. Hewever no technology is developed to our own groundstation for NOAA satellite. The purpose of this paper is to build a home-made NOAA APT groundstation and image processing system to supply this system to secondary school or college.

• Journal of Ocean Engineering and Technology
• /
• v.35 no.5
• /
• pp.336-346
• /
• 2021

The prediction of wave conditions is crucial in the field of marine and ocean engineering. Hence, this study aims to predict the significant wave height through machine learning (ML), a soft computing method. The adopted metocean data, collected from 2012 to 2020, were obtained from the Korea Institute of Ocean Science and Technology. We adopted the feedforward neural network (FNN) and long-short term memory (LSTM) models to predict significant wave height. Input parameters for the input layer were selected by Pearson correlation coefficients. To obtain the optimized hyperparameter, we conducted a sensitivity study on the window size, node, layer, and activation function. Finally, the significant wave height was predicted using the FNN and LSTM models, by varying the three input parameters and three window sizes. Accordingly, FNN (W48) (i.e., FNN with window size 48) and LSTM (W48) (i.e., LSTM with window size 48) were superior outcomes. The most suitable model for predicting the significant wave height was FNN(W48) owing to its accuracy and calculation time. If the metocean data were further accumulated, the accuracy of the ML model would have improved, and it will be beneficial to predict added resistance by waves when conducting a sea trial test.

• Korean Journal of Remote Sensing
• /
• v.35 no.1
• /
• pp.151-162
• /
• 2019

Surface temperature has been derived from the MODIS/ASTER airborne simulator (MASTER) mid-wave infrared single channel data using the MODerate resolution atmospheric TRANsmission (MODTRAN) radiative transfer model with input data including the University of Wisconsin (UW) emissivity, the National Centers for Environmental Prediction (NCEP) atmospheric profiles, and solar and line-of-sight geometry. We have selected the study area that covers some surface types such as water, sand, agricultural (vegetated) land, and clouds. Results of the current study show the reasonable geographical distribution of surface temperature over land and water similar to the pattern of the MASTER L2 surface temperature. The thorough quantitative validation of surface temperature retrieved from this study is somehow limited due to the lack of in-situ measurements. One point comparison at the Salton Sea buoy shows that the present estimate is 1.8 K higher than the field data. Further comparison with the MASTER L2 surface temperature over the study area reveals statistically good agreement with mean differences of 4.6 K between two estimates. We further analyze the surface temperature differences between two estimates and find primary factors to be emissivity and atmospheric correction.

• Journal of the Korean Institute of Rural Architecture
• /
• v.21 no.2
• /
• pp.35-42
• /
• 2019

There are 17,427 reservoirs in Korea, of which about 96% were built before the mid 1980s. Therefore, aging is severe and reinforcement are necessary. In addition, aged reservoirs, which are more than 50 years old, account for 70% of the total. Therefore, there is a problem such as the collapse of the reservoir and the decrease of the storage capacity due to progress of aging with time. The grouting method using cement is mainly used as maintenance and reinforcement method of old reservoir. However, the grouting method using cement has engineering and environmental problems. In order to solve the engineering and environmental problems of cement grouting method, an eco-friendly grouting material was developed that mixes circular resource grouting binder, high molar ratio sodium silicate and colloidal silica. The engineering and environmental properties of the developed injection materials were evaluated by conducting gel time, homo-gel strength, sea water resistance test and environmental stability evaluation. Also, examined the possibility of replacing OPC existing aged reservoir reinforcement methods. As a result, it was found out that it was better than the conventional cement method in terms of engineering and environment. However, since this study is the result of laboratory test, it is necessary of verify the application at field of aged reservoir.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.52 no.1
• /
• pp.59-66
• /
• 2019

The growth and maturation pattern of a commercial and endemic red algae Meristotheca papulosa were investigated in Jeju Island. Ecological researches were performed in a natural population of 10 m water depth in Sinheung from march 2014 to November 2015. Maximal blade length and weight of M. papulosa were 8.7 cm and 5.49 g in July 2014 and 10.7 cm and 10.17 g in September 2015, respectively. Growth in blade area of the species reached a maximum of $43.84cm^2$ and $67.41cm^2$ in July 2014 and 2015, respectively. Thalli in the field population were rarely observed from October to December but new recruits were found from January, following year. Carposporophytes were observed from June to September when bottom seawater temperatures were around $20^{\circ}C$. At the study site, seawater temperature was in the range of $14.9-25.7^{\circ}C$. Growth parameters of M. papulosa and relative abundance of carposporophytes showed significant correlation with environmental factors (temperature, salinity, DIN). In this result, we clarified the growth and maturation period of M. palpulosa, and provided effective data on the protection and management of natural populations and basic data for mass culture of the alga.

• Journal of Species Research
• /
• v.10 no.1
• /
• pp.12-22
• /
• 2021

During a comprehensive investigation of indigenous prokaryotic species in Korea, 25 and 10 bacterial strains assigned to the classes Alphaproteobacteria and Betaproteobacteria, respectively, were isolated from diverse environmental habitats, including soil, mud, tidal field, sea water, sand, rusted iron, and leaf. Based on their high 16S rRNA gene sequence similarities (>98.7%) and the formation of robust phylogenetic clades with type species, each strain was assigned to an independent and predefined bacterial species. Since there were no published or official reports regarding these 35 isolates in Korea, they - 25 species of 14 families in the 5 orders of Alphaproteobacteria and 10 species of 3 families in the two orders of Betaproteobacteria - have been reported as unrecorded species in Korea. In addition, Gram reaction, colony and cell morphology, basic biochemical characteristic, isolation source, and strain ID of each species are also described in the species description sections.

• Journal of Marine Bioscience and Biotechnology
• /
• v.13 no.1
• /
• pp.20-27
• /
• 2021

Ironically, marine bioresource production in Chungnam Province is the second-largest in the country. The province's marine bioresource production puts its lack of a marine bioindustry in the spotlight despite the region's favorable conditions to produce representative value-added and (ultra) high value-added products such as neutraceutical and/or pharmaceutical function. This juxtaposition is to be expected, as there are no institutions for training professionals in the field of marine biology or in the fisheries industry in the West Sea area. The unique features of the region require individuals with specialized training who have been educated in accordance with regional development and the specificity of the region. Recently, however, a plan has been initiated at the national level to foster the growth of the marine biology industry in the Chungnam Province on Korea's west coast. This plan includes increasing funds to the marine biology market to 1.2 trillion by 2030. If the Chungnam region wants to successfully revitalize the marine biology industry and put the increased funds to efficient use, it must first establish various research and (business) development (R&(B)D) plans regarding local marine biology infrastructures and marine biology programs at local universities. It must also focus on training specialists to protect, maintain, and develop the region's marine bio-resources to increase the growth of the region's bioindustry.