• Maritime Security
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• v.6 no.1
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• pp.37-56
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• 2023

Recently, with the rapid development of ICT(Information and Communication Technology) and AI(Artificial Intelligence) technology industries, the emergence of MASS(Maritime Autonomous Surface Ship), which were thought only in the distant future, is approaching a reality. Along with the development of these amazing technologies, changes in the private law sector, such as liability, compensation for damages, and maritime insurance, as well as in the public law sector, such as maritime safety, marine environment protection, and maintenance of maritime order, have become necessary in the field of maritime law. In particular, with the advent of a new type of ship called MASS that does not have a crew on board, the kind and type of liability, compensation for damages, and insurance contracts in the event of a marine accident will also change. In this paper, the general theory about concept, classification, effectiveness and future of MASS and the general theory about concept and various obligations and responsibilities under the maritime law for discussion of MASS are reviewed. Next, in addition, regarding the problems that may occur in the event of a marine accident from MASS, the status as a ship, the legal relationship of the chartering contract, obligation to exercise due diligence in making the vessel seaworthiness, subject of responsibility, and liability for damages and immunity are reviewed from the perspective of maritime law. In addition, in the degree four of MASS, the necessities of further research to clarify the attributable subjects and standards of responsibility in the event of a marine accident, as well as the necessities of institutional improvement such as technology development, enactment and amendment of law and funding are presented.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.127-128
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• 2021

This study suggests surface wave communication, which uses a metal surface as a medium, to provide wireless communication in the extreme environment due to surrounding metal materials on vessels. The test was conducted on a G/T 265 tons tug boat, and to confirm the possibility of surface wave communication between a bridge and each designated space in the boat. As a result, the transmission speed was 13Mbps in average. For the test case between the bridge and the engine room, transmission speed was 4.3Mbps while the engine was on, and 1.2Mbps during sailing. It was able to be overcome by partially changing the equipment installation location. Surface wave communication in a bow storage, a fully enclosed space, had 8Mbps better transmission speed than wireless communication; this confirmed the superiority of surface wave communication in confined spaces on a vessel. Additional surface wave generators were designed and applied to resolve the paint issue. It is expected to apply surface wave communication to implement the new wireless solution on vessels.

• Journal of Bio-Environment Control
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• v.8 no.1
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• pp.56-66
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• 1999

Growth of Dendranthema grandiflorum R. ‘Bongwhang’plantlets, as affected by three levels of photosynthetic photon flux (PPF), 70, 150 and 220 $\mu$mol. $m^{-2}$ . $s^{-1}$ , three levels of C $O_{2}$ concentration, 400-500 (ambient), 1000 and 2000 $\mu$mol.mo $l^{-1}$ , and two levels of number of air exchanges per hour (NAEH), 0.1 $h^{-1}$ and 2.8 $h^{-l}$, was studied. Explants were obtained from photomixotrophically-micropropagated plantlets. Four explants were planted in each 3.7$\times$10$^{-4}$ $m^{3}$ polycarbonate box containing MS medium supplemented with 1.25 meq. $L^{-1}$ $H_{2}$P $O_{4}$$^{[-10]}$ and no added sugar. Explants were cultured under cool-white fluorescent lamps (16 h. $d^{-1}$ ), at 25$\pm$1$^{\circ}C$ temperature, and 70-80% relative humidity. In treatments of 2.8 $h^{-1}$ NAEH, a 10 mm round hole made on the vessel cap was sealed with a microporous filter For higher C $O_{2}$ concentrations in the culture room, C $O_{2}$ gas was provided from a tank of liquefied C $O_{2}$. Fresh and dry weights, height, length of the longest roots, number of leaves, and leaf area significantly increased with increasing PPF and especially, with increasing C $O_{2}$ concentration. Growth was enhanced with increased number of air exchanges per hour (2.8 $h^{-1}$ ). Overall, treatment of 220$\mu$mol. $m^{-2}$ . $s^{-1}$ PPF combined with 2000$\mu$mol.mo $l^{-1}$ C $O_{2}$ and 2.8 $h^{-1}$ NAEH gave the most vigorous growth of Dendranthema grandiflorum R. ‘Bongwhang’ plantlets in vitro.o.

• Journal of Mushroom
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• v.12 no.3
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• pp.209-215
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• 2014

Changes in physical and chemical properties of oak sawdust were investigated by depth and time for 46 days during the fermentation process of 33 tons of the sawdust for oak mushroom cultivation. The degrees of change in the properties of the sawdust differed depending on the depth and fermentation period. Most of the physical-chemical properties except temperature and pH gradually changed during the fermentation. The temperature change was highly sensitive to the environment at the surface sawdust to 20 cm depth, while it gradually increased to the maximum $58.9^{\circ}C$ at 40~100 cm depths in 12 days and slowly to the maximum at 150 cm depth in 24 days. The moisture content of the sawdust decreased gradually from 31% to 26.5~28.0% in 24 days. Of the chemical properties during the fermentation, pH generally rose from 5.2 to 5.6, but it decreased to 4.4~4.7 at 150 cm depth in 16 days. While the carbon content of the sawdust was 68~70% without significant change, nitrogen content increased from 0.22% to 0.25% and thus C/N ratio gradually lowered from 320 to 280. P content in the sawdust gradually increased from 0.005% to 0.022% for 46 days. Osmotic concentration of the hot water extract of the sawdust varied 41.5~44.2 mmol/kg without significant change by the depth and time. The starch particles within initial ray parenchyma cells of sawdust decreased and fungal hyphae formed on the surface of the sawdust granules and within xylem vessel cells in 35 days. The effect of the sawdust fermentation on oak mushroom cultivation needs continued research.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.6
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• pp.659-665
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• 2008

This study is about zeolite synthesis from the sewage sludge incinerator fly ash of "S" sewage treatment center located in Seoul. For this purpose, the properties of raw fly ash as starting material, the hydrothermal conditions for zeolite synthesis and the environmental applicabilities of synthesized zeolites were examined. Fly ash from sewage sludge incinerator has large quantities of SiO$_2$ and Al$_2$O$_3$ and their contents are 42.8 wt.% and 21.2 wt.% respectively. So fly ash is considered to be possible starting material for zeolite synthesis. The results from leaching test of fly ash showed that the concentration of hazardous metals were very low as compared with the Korea leaching standard of the Waste Management Law. But the concentration from total recoverable test of fly ash were higher than the fertilizer standard of Fertilizer Management Law. Major zeolite products synthesized by hydrothermal reaction are analcime in teflon vessel and zeolite P1 in borosilicate flask. Optimum conditions for the synthesis of analcime were 1 N of NaOH concentration, 16 hour of reaction time and 135$^{\circ}C$ of reaction temperature. For the zeolite P1 formation, the proper conditions were demonstrated to be 5 N of NaOH concentration, 16 hour reaction time and 130$^{\circ}C$ of reaction temperature in this study. Hazardous metal contents in the analcime product are similar with those in raw fly ash. In case of the zeolite P1, the contents are reduced to nearly a half. Raw fly ash and the analcime product showed NH$_4{^+}$ ion exchange capacity of 0$\sim$1.0 mg of NH$_4{^+}$g$^{-1}$ and 3.0$\sim$7.4 mg of NH$_4{^+}$g$^{-1}$, respectively. However, the zeolite P1 product reached exchange capacity to 14.6$\sim$17.8 mg of NH$_4{^+}$g$^{-1}$. This values are in the range of those of natural clinoptilolite and phillipsite. From this point of view, zeolite synthesis from sewage treatment sludge incinerator fly ash is a good alternative for solid waste recycling.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.2
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• pp.163-174
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• 2020

Particulate matter levels are rapidly increasing daily, and this can affect human health. Therefore, air pollutant emissions from sea vessels require management. This study evaluates the status of air pollutants, focusing on air pollutant emissions from the vessels of the Korea Coast Guard (KCG), and proposes national management measures to reduce emissions. According to a report recently released (2018) by the National Institute of Environmental Research (NIER), emissions from vessels constituted 6.4 % of the total domestic emissions, including 13.1 % NO_x, 10.9 % SO_x, and 9.6 % particulate matter (PM10/PM2.5). Among the rates of pollutant emission from vessels, the emission rates of domestic and overseas cargo vessels were the highest (50.6 %); the ratio of fishing boats was 42.6 %. With respect to jurisdictional sea area, 44.1 % of the emissions are from the south sea, including the Busan and Ulsan ports, and 24.8 % of the emissions are from the west sea, including the Gwangyang and Yeosu ports. The KCG inspects boarding lines to manage emission conditions and regulate air pollutant emissions, but it takes time and effort to operate various discharge devices and measure fuel oil standards. In addition, owing to busy ship schedules, inspection documents are limited in terms of management. Therefore, to reduce the air pollutant emissions of such vessels, regulations will be strengthened to check for air pollutants, and a monitoring system based on actual field data using KCG patrol ships will be established, for each sea area, to manage the emissions of such vessels. Furthermore, there is a need for technological development and institutional support for the introduction of environmentally friendly vessels.

• Geophysics and Geophysical Exploration
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• v.11 no.1
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• pp.52-59
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• 2008

We have developed a new deep-towed marine DC resistivity survey system. It was designed to detect the top boundary of the methane hydrate zone, which is not imaged well by seismic reflection surveys. Our system, with a transmitter and a 160-m-long tail with eight source electrodes and a receiver dipole, is towed from a research vessel near the seafloor. Numerical calculations show that our marine DC resistivity survey system can effectively image the top surface of the methane hydrate layer. A survey was carried out off Joetsu, in the Japan Sea, where outcrops of methane hydrate are observed. We successfully obtained DC resistivity data along a profile ${\sim}3.5\;km$ long, and detected relatively high apparent resistivity values. Particularly in areas with methane hydrate exposure, anomalously high apparent resistivity was observed, and we interpret these high apparent resistivities to be due to the methane hydrate zone below the seafloor. Marine DC resistivity surveys will be a new tool to image sub-seafloor structures within methane hydrate zones.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.233-238
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• 2005

Growth of Campanula punctata 'Rubriflora' plantlets, as affected by three levels of photosynthetic photon flux (PPF), 70, 110, and $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, two levels of $CO_2$ concentration, 500 and $1,500{\mu}mol{\cdot}m^{-1}$, and two levels of number of air exchanges per hour (NAEH), 0.1 and $2.8 h^{-l}$, was studied. Explants were obtained from photomixotrophically-micropropagated plantlets. Four explants were planted in each $3.7{\times}10^{-4}m^3$ polycarbonate box containing MS basal medium and no added sucrose. Explants were cultured under cool-white fluorescent lamps for $16h{\cdot}d^{-1},\;at\;25\pm1^{\circ}C$ temperature, and $70\~80\%$ relative humidity In treatments of $2.8h^{-1}$ NAEH, a 10mm round hole made on the vessel cap was sealed with a microporous filter. For higher $CO_2$ concentrations in the culture room, $CO_2$ gas was provided from a tank of liquefied $CO_2$. Fresh and dry weights, length of the longest root, and number of leaves significantly increased with increasing PPF and especially $CO_2$ concentration. Length of the longest root, number of leaves, fresh and dry weights, and chlorophyll concentration were enhanced with increased NAEH. However, leaf area was the smallest in the $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}\;PPF\;2.8h^{-1}$ NAEH and especially, $1,500{\mu}mol{\cdot}mol^{-1}\;CO_2$ concentration treatment. Treatment effect became more produced with time. Overall, treatment with $220{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}\;PPF\;and\;1,500{\mu}mol{\cdot}mol^{-1}\;CO_2$ gave the most vigorous growth.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.628-636
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• 2018

Because large buoys are mainly made of steel, they are heavy and vulnerable to corrosion by sea water. This makes buoy installation and maintenance difficult. Moreover, vessel collision accidents with buoys and damage to vessels due to the material of buoys (e.g., steel) are reported every year. Recently, light buoys adopting eco-friendly and lightweight materials have come into the spotlight in order to solve the previously-mentioned problems. In Korea, a new lightweight buoy with a 7-Nautical Mile lantern adopting expanded polypropylene (EPP) and aluminum to create a buoyant body and tower structure, respectively, was developed in 2017. When these light buoys are operated in the ocean, the visibility and angle of light from the lantern installed on the light buoys changes, which may cause them to function improperly. Therefore, research on the performance of light buoys is needed since the weight distribution and motion characteristics of these new buoys differ from conventional models. In this study, stability estimation and motion analyses for newly-developed buoys under various environmental conditions considering a mooring line were carried out using ANSYS AQWA. Numerical simulations for the estimation of wind and current loads were performed using commercial CFD software, Siemens STAR-CCM+, to increase the accuracy of motion analysis. By comparing the estimated maximum significant motions of the light buoys, it was found that waves and currents were more influential in the motion of the buoys. And, the estimated motions of the buoys became larger as the sea state became worser, which might be the reason that the peak frequencies of the wave spectra got closer to those of the buoys.

• Journal of Bio-Environment Control
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• v.13 no.1
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• pp.51-55
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• 2004

The most commonly used inorganic nutrient compositions such as Murashige & Skoog medium have been optimized for heterotrophic growth. Therefore, they may not be optimal for photomixotrophic and photoautotrophic growth of plantlets. In photomixotrophic micropropagation, emdium sugar level is often lowered, while light and $CO_2$ levels in vessel are raised, and chlorophyllous explants are used to facilitate photosynthetic carbon acquisition. In a factorial experiment effect of addition (+) and omission(_) of organic materials (OM, 0.5 g ${\cdot}$ $m^{-3}$ each of thiamine, nicotinic acid and pyridoxine and 100 ${\cdot}$ $m^{-3}$ myo-inositiol) combined with three sucrose levels (0, 15, and 30 kg ${\cdot}$ $m^{-3}$) was tested on the growth of potato plantlets. Each of nodal cuttings with a leaf was cultured on 0.1${\times}$$10^{-4}m^{-3}$) MS agar ( 8 kg ${\cdot}$ $m^{-3}$) medium (pH 5.80 before autoclave) in glass test tubes (100 mm${\times}$25mm) capped with a sheet of transparent film with a 6 mm diameter gas permeable filter (5.1 air exchanges ${\cdot}$$h^{-1}$). Cultures were maintained in a room for 27 days at $23^{\circ}C$, 50% RH, 350-450${\mu}mol\;{\codt}\;mol^{-1}CO_2$, 16 h ${\cdot}$ $d^{-1}$ photoperiod at 13${\mu}mol\;{\codt}\;m\;{\codt}\;s^{-1}$ PPFD provided by white cool fluorescent lamps. Growth of potato plantlet in the +OM and -OM treatments were similar, while medium pH was 0.2 scale lower in the latter. Dry weight, % dry matter, and stem diameter enhanced, while shoot to root dry weight ratio, leaf area, chlorophyll concentration per gram dry weight, and medium pH decreased with increasing initial sucrose level. Interaction between OM and sucrose levels was observed in shoot length and medium pH. Results indicate that OM can be omitted from the medium without detrimental effect while addition of sucrose was beneficial for the photomixotrophic growth of potato plantlets under raised light and $CO_2$.