• Korean Journal of Remote Sensing
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• v.14 no.4
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• pp.353-365
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• 1998

Light absorption coefficient per unit mass of particles, i.e., specific absorption coefficient, is important as one of the main parameters in developing algorithms for ocean color remote sensing. Specific absorption coefficient of chlorophyll ($a^*_{ph}$) and suspended sediment ($a^*_{ss}$) were analyzed with a spectrophotometer using the "wet filter technique" and "Kishino method" for the seawater collected in the Yellow and Mediterranean Sea. An improved data-recovery method for the filter technique was also developed using spectrum slopes. This method recovered the baselines of spectrum that were often altered in the original methods. High $a^*_{ph}({lambda})$ values in the oligotrophic Mediterranean Sea and low values in the Yellow Sea were observed, ranging 0.01 to 0.12 $m^2$/mg at the chlorophyll maximum absorption wavelength of 440 nm. The empirical relationship between $a^*_{ph}$(440nm) and chlorophyll concentrations () was found to fit a power function ($a^*_{ph}$=0.039 $^{-0.369}$), which was similar to Bricaud et al. (1995). Absorption specific coefficients for suspended sediment ($a^*_{ss}$) did not show any relationship with concentrations of suspended sediment. However, an average value of $a^*_{ss}$ ranging 0.005 - 0.08 $m^2$/g at 440nm, was comparable to the specific absorption coefficient of soil (loess) measured by Ahn (1990). The morepronounced variability of $a^*_{ss}$ than $a^*_{ph}$ was determined from the variable mixing ratio values between particulate organic matter and mineral. It can also be explained by a wide size-distribution range for SS which were determined by their specific gravity, bottom state, depth and agitation of water mass by wind in the sea surface.

• Food Science and Industry
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• v.51 no.4
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• pp.278-301
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• 2018

Although more than 80% of living organisms are found in marine ecosystems, only less than 10% of marine resources have been utilized for human food consumptions and other usages. It is well known that marine resources (fish, shellfish and algae) have exceptional nutritional properties; however, their functional characteristic has not been completely discovered. It is believed that metabolites (organic compounds, proteins, peptides, lipids, minerals, etc.) play an important role to show its biological properties. Marine proteins and peptides are considered to be future drugs due to their excellent biological activities with a fewer adverse side effect. Marine peptides show several biological activities, including antimicrobial, antioxidant, anti-inflammatory, anti-cancer, anti-viral, anti-tumor, anti-diabetic, anti-hypertensive, anti-coagulant, immunomodulatory, appetite suppressing and neuroprotective effects. Therefore, the pharmaceutical, nutraceutical, and cosmeceutical companies have been paid attention to the marine peptides to commercialize into products. This current review mainly focused on the above mentioned biological activities of marine peptides and protein hydrolysates as a functional food and pharmaceutical applications. To commercialize these materials in industrial level required large quantity in high-purity level, and it is complicated to produce huge quantity from the marine resources due to insufficient raw materials, unavailability of raw materials through a year, hinder the growth with geographical variations, and availability of compounds in extreme small quantities. The best solution for these issues is to introduce new modern technologies such as artificial intelligence robots, drones, submersibles and automated raw material harvesting vessels in farming industries instead of man power, which will lead to 4th industrial revolution.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.4
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• pp.316-333
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• 2021

In order to understand basic data for improving the fishing system and fishing vessel structure in coastal improved stow net fishery, a questionnaire survey and on-site hearing were conducted from May 10 to June 11, 2019 to analyze opinions on the improvement of operation status and fishing vessel structure. The questionnaire survey consisted of ten questions on the operation status of coastal improved stow net fishery and six questions on the improvement of fishing vessel structure, and the results of each question were analyzed by the region, the captain's age, the captain's career and the age of fishing vessel. As a result of analyzing opinions on the operation status of the coastal improved stow net fishery, it was found that the average time required for casting net was 32.8 to 33.0 minutes and that the average time required for hauling net was 41.0 to 42.2 minutes which took 10 to 12 minutes more than for casting net. The most important work requiring improvement during fishing operation (the first priority) were 'hauling net operation,' 'readjustment and storage of fishing gear,' and 'fish handling' and the hardest factor in fishing management were in the order of 'reduction of catch,' 'labor shortage' and 'rising labor costs.' The most institutional improvement that is most needed in coastal improved stow net fishery was an 'using fine mesh nets.' Most of the respondent to the questions on the experience in hiring foreign crews was 'either hiring or willing to hire foreign crews,' and the average number of foreign crews employed was found to be 2.3 to 2.4 persons. The most important reason for hiring (or considering employment) foreign crews was 'high labor costs.' The degree of communication with foreign crews during fishing operation were 'moderate' or 'difficult to direct work.' The most important problem in hiring foreign crews (the first priority) was an 'illegal departure.' As the survey results on the opinion of structural improvement of coastal improved stow net fishing vessel, the degree of satisfaction with fishing vessel structure related to fishing operation was found to be somewhat unsatisfactory, with an average of 3.3 points on a five-point scale. The inconvenient structure of fishing vessel in possession (the first priority), the space needed most for the construction of new fishing vessel (the first priority) and the space considered important for the construction of new fishing vessel (the first prioprity) was a 'fish warehouse.' The most preferred equipment for the construction of new fishing vessel were 'engine operation monitoring' and 'navigation safety devices.' The average size (tonnage class), the average horse power and the average total length of fishing vessel for proper profit and safety fishing operation was between 13.8 and 14.0 tonnes, 808.3 to 819.5 H.P. and 23.4 to 23.5 meters, respectively. The results of the operation status of coastal improved stow net fishery and the requirement for improving the fishing vessel structure are expected to be provided as basic data for reference when we build or improve the fishing vessel.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.6
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• pp.620-625
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• 2015

In an effort to reduce the onset of global warming, the International Maritime Organization Marine Environment Protection Committee (IMO MEPC) proposed the reduction in ship speeds as a way of lowering the proportion of carbon dioxide ($CO_2$) in the Green House Gas emissions from ships. To minimize fuel costs, shipping companies have already been performing slow steaming for their own fleets. Specifically, the slow steaming approach has been adopted for most ocean-going container lines. In addition, because of the increased marine fuel cost that is required to enable increased capacity, there is an urgent need for more advanced fuel-saving technologies. Therefore, in this present study, we propose a fuel-cost reduction method that can improve the performance of diesel engines. We introduce a predetermined amount (0.025% of the amount of fuel used) of fuel additive (oil-soluble calcium-based organometallic compound). For improved experimental accuracy, as the test subjects, we utilize a large two-stroke diesel engine installed in land plants. The loads of the test engine were classified as low, medium, and high (50, 75, and 100%, respectively). We compare the engine performance parameters (power output, fuel consumption rate, p-max, and exhaust temperature) before and after the addition of fuel additives. Our experimental results, confirmed that we can realize fuel-cost savings of at least 2% by adding the fuel additive in low load conditions (50%). Likewise, the maximum combustion pressure was found to have increased. On the other hand, we observed that there was a reduction in the exhaust temperature.

• Strategy21
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• s.31
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• pp.142-163
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• 2013

Ieodo is a submerged rock within a Korea's Exclusive Economic Zone(EEZ) in the East China Sea with its most shallow part about 4.6m below the sea level which has no specific rights for the EEZ delimitation. The United Nations Convention on the Law of the Sea (UNCLOS) stipulates that any coastal state has the rights to claim an EEZ that stretches up to 200 nautical miles from its shore, except where there is an overlap with a neighboring country's claims. Korea claims that Ieodo is within its EEZ as it sits on the Korean side of the equidistant line and the reef is located on the Korea section of the continental shelf. China does not recognize Korea's application of the equidistance principle and insists that Ieodo lies on its continental shelf. According to UNCLOS, Ieodo is located in international waters, rather than one country's EEZ as the two countries have failed to reach a final agreement over the delimitation of the maritime border. This study seeks to understand the evolution of the People's Liberation Army Navy(PLAN) strategy as main obstacles for the EEZ delimitation between Korea and China. PLAN's Strategy evolves from "coastal defense" to "offshore defence", since the late 1980s from a "coastal defence" strategy to an "offshore defence" strategy which would extend the perimeter of defence to between 200 nm and 400 nm from the coast. China's economic power has increased It's dependence on open trade routes for energy supplies and for its own imports and exports. China want secure Sea Lane. PLAN's "offshore defence" strategy combines the concept of active defence with the deployment of its military forces beyond its borders. China's navy try to forward base its units and to achieve an ocean going capability. China's navy expects to have a 'Blue Water' capability by 2050. China insists that coastal states do have a right under UNCLOS to regulate the activities of foreign military forces in their EEZs. China protests several times against US military forces operating within It's EEZ. The U.S. position is that EEZs should be consistent with customary international law of the sea, as reflected in UNCLOS. U.S. has a national interest in the preservation of freedom of navigation as recognized in customary international law of the sea and reflected in UNCLOS. U.S. insists that coastal states under UNCLOS do not have the right to regulate foreign military activities in their EEZs. To be consistent with its demand that the U.S. cease performing military operations in china's EEZ, China would not be able to undertake any military operations in the waters of South Korea's EEZ. As such, to preserve its own security interests, China prefers a status quo policy and used strategic ambiguity on the Ieodo issue. PLAN's strategy of coastal defence has been transformed into offensive defence, Korea's EEZ can be a serious limitation to PLAN's operational plan of activities. Considering China'a view of EEZs, China do not want make EEZ delimitation agreement between Korea and China. China argues that the overlapping areas between EEZs should be handled through negotiations and neither side can take unilateral actions before an agreement is reached. China would prefer Ieodo sea zone as a international waters, rather than one country's EEZ.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.249-255
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• 2010

Since the 1990's, a number of ULF geomagnetic disturbance associated with earthquake occurrences have actively been reported, and polarization analysis of geomagnetic fields becomes one of potential candidates to be capable of predicting short-term earthquake. This study develops the modified polarization analysis method based on the previous studies, and analyzes three-component geomagnetic fields obtained at Cheongyang geomagnetic observatory using the developed method. A daily polarization value (the ratio of spectral power of horizontal and vertical geomagnetic field) is calculated with a focus on the 0.01 Hz band, which is known to be the most sensitive to seismogenic ULF radiation. We analyze a total of 10 months of geomagnetic data obtained at Cheongyang observatory, and compare the polarization values with the Kp index and the earthquake occurred in the analysis period. The results show that there is little correlation between the temporal variations of polarization values and Kp index, but remarkable increases in polarization values are identified which are associated with two earthquakes. Comparison the polarization values obtained at Cheongyang and Kanoya observatory indicates that the increases of polarization values at Cheongyang might be due to not global geomagnetic induction but the locally occurred earthquakes. Furthermore, these features are clearly shown in normalized polarization values, which take account in the statistical characteristics of each geomagnetic field. On the basis of these results, polarization analysis can be used as promising tool for monitoring the earthquake-precursory phenomenon.

• Resources Recycling
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• v.23 no.6
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• pp.3-11
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• 2014

Bottom ash from coal fired power plants is not widely used due to a broad range of particle sizes and a high carbon content for producing geopolymers. The effect of mechanical activation on compressive strength of bottom ash- based geopolymers was examined by rod and planetary-ball milling to encourage full-fledged recycling of bottom ash, the main component of pond ash. The amount of amorphous component in the milled ash samples did not change significantly after the mechanical activation. It is presumably because needle-shaped mullite crystals, which is a major crystalline phase and grown in a glassy matrix, possess high strength and toughness, and therefore, they could endure external shocks and remain almost intact. Milling operation, however, decreased the particle size and improved the homogeneity of ash, thereby leading to increase reactivity of milled ash with alkali activators. Rod milling produced a relatively narrow particle size distribution of the milled ash particles; however, it was less effective in reducing the particle size. Nevertheless, it was interesting to observe that rod milling had equal effect on improving the compressive strength of geopolymers up to about 37%, as that of planetary ball milling. Rod milling is believed to be suitable process for enhancing the reactivity of bottom ash for large-scale recycling of bottom ash and producing geopolymers.

• Economic and Environmental Geology
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• v.50 no.2
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• pp.159-170
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• 2017

The temporal and spatial temperature distribution of the heat storage mortar made of porous feldspar was measured and the thermal properties and electricity consumption were analyzed. For the experiment, two real size chambers (control model and test model) with hot water pipes were constructed. Two large scale models with hot water pipes were constructed. The surface temperature change of the heat storage layer was remotely monitored during the heating and cooling process using infrared thermal imaging camera and temperature sensor. The temperature increased from $20^{\circ}C$ to $30^{\circ}C$ under the heating condition. The temperature of the heat storage layer of the test model was $2.0-3.5^{\circ}C$ higher than the control model and the time to reach the target temperature was shortened. As the distance from the hot water pipe increased, the temperature gap increased from $4.0^{\circ}C$ to $4.8^{\circ}C$. The power consumed until the surface temperature of the heat storage layer reached $30^{\circ}C$ was 2.2 times that of the control model. From the heating experiment, the stepwise temperature and electricity consumption were calculated, and the electricity consumption of the heat storage layer of the test model was reduced by 66%. In the cooling experiment, the surface temperature of the heat storage layer of the test model was maintained $2^{\circ}C$ higher than that of the control model. The heat storage effect of the porous feldspar mortar was confirmed by the temperature experiment. With considering that the time to reheat the heat storage layer is extended, the energy efficiency will be increased.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.276-289
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• 2013

In developing offshore wind farms, many environmental issues arise because of the concentration on supply demand and economic logic. Accordingly, community conflict is induced. Especially, recent studies regarding the capacity and location of offshore wind development have been conducted considering wind states and ocean conditions, etc. of coastal seas in Republic of Korea. Nevertheless, studies on the impact of marine environments and ecosystems are very limited so far. Environmental monitoring that follows development projects has been actively done in the offshore wind farms in many developed European countries. In contrast, there is no domestic monitoring data regarding environmental impacts caused by installing and operating offshore wind power. Therefore, the environmental impacts under construction and operation phases as well as the guidelines in the stage of environmental impact assessment suited for domestic coastal seas are well presented in this study by analyzing monitoring cases and references of overseas offshore wind farm. For this reason, this research is ultimately aimed at minimizing the environmental impact in offshore wind farm development and thus simplify administrative procedures in Korea.

• Strategy21
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• s.42
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• pp.53-82
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• 2017

Samuel Eliot Morison (1887-1976) was one of the pre-eminent historians of his generation. He was not only a famous historian at that time, but also was promoted to the rank of Admiral in U.S. Navy Reserve. Fifteen volume History of United States Naval Operations in World War II was published between 1947 and 1962, was not only a comprehensive report on the Navy's projection of power over two oceans, but a classic of historical literature that stands as the definitive treatment of it subject. Although he was fifty-five when war come to America in December 1941. Samuel Eliot Morison was determined to play a role. A professor at Harvard at the time, he joined volunteering for duty in the Navy. An experienced sailor, Professor Morison had earlier sailed that same routes taken by Christopher Columbus while researching his biography, Admiral of the Ocean Sea, which appeared in January 1942 th much acclaim and later got a Pulitzer Prize. Thus Morison plunged into the war, crossing the Atlantic aboard a destroyer. He assumed himself as "Parkman on the sea", tried to follow Parkman's historiographic method, not only participatory history but also literary style. And during writing History of United States Naval Operations in World War II, He emphasized two principles, publicity and objectivity. In terms of publicity, he always worried about who read history and why. In his pamphlet, "History as a Literary Art", he asserted it is useless if readers do not read a history which historians wrote. So he thought historians have forgotten that there is an art of writing of history. Therefore, he built his narratives around brightly rendered visuals and used the present tense to describe actions he witnessed firsthand, he wrote of the U.S. combat in very vividly. But strongly driven by publicity, he sometimes lost his balance in writing the naval history. For instance, the naval history became the focus of criticism for its prejudiced comments about the commanders. Also some reviewers asserted he did not secure the objectivity on writing the naval history. Although he sometimes deliberately torpedoed the objectivity of his work for strengthening publicity, by writing an extensive U.S. naval history, he introduced maritime history and naval history to the public widely. Until in early twentieth century, U.S. historians usually had been focusing their effort to the traditional areas, for example politic, economy, and etc. His intensive effort on the operations of U.S. Navy in World War II aroused a public interest in maritime and naval history. In conclusion, through using literary style and realistic narratives, historian Morison wrote a naval history for all the people which could appealed to the public.