• International Journal of Highway Engineering
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• v.17 no.4
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• pp.11-18
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• 2015

PURPOSES: This study aims to evaluate the runoff reduction with permeable pavements using the SWMM analysis. METHODS: In this study, simulations were carried out using two different models, simple and complex, to evaluate the runoff reduction when an impermeable pavement is replaced with a permeable pavement. In the simple model, the target area for the analysis was grouped into four areas by the land use characteristics, using the statistical database. In the complex model, simulation was performed based on the data on the sewer and road network configuration of Yongsan-Gu Bogwang-Dong in Seoul, using the ArcGIS software. A scenario was created to investigate the hydro-performance of the permeable pavement based on the return period, runoff coefficient, and the area of permeable pavement that could be laid within one hour after rainfall. RESULTS : The simple modeling analysis results showed that, when an impervious pavement is replaced with a permeable pavement, the peak discharge reduced from $16.7m^3/s$ to $10.4m^3/s$. This represents a reduction of approximately 37.6%. The peak discharge from the whole basin showed a reduction of approximately 11.0%, and the quantity decreased from $52.9m^3/s$ to $47.2m^3/s$. The total flowoff reduced from $43,261m^3$ to $38,551m^3$, i.e., by approximately 10.9%. In the complex model, performed using the ArcGIS interpretation with fewer permeable pavements applicable, the return period and the runoff coefficient increased, and the total flowoff and peak discharge also increased. When the return period was set to 20 years, and a runoff coefficient of 0.05 was applied to all the roads, the total outflow reduced by $5195.7m^3$, and the ratio reduced to 11.7%. When the return period was increased from 20 years to 30 and 100 years, the total outflow reduction decreased from 11.7% to 8.0% and 5.1%, respectively. When a runoff coefficient of 0.5 was applied to all the roads under the return period of 20 years, the total outflow reduction was 10.8%; when the return period was increased to 30 and 100 years, the total outflow reduction decreased to 6.5% and 2.9%, respectively. However, unlike in the simple model, for all the cases in the complex model, the peak discharge reductions were less than 1%. CONCLUSIONS : Being one of the techniques for water circulation and runoff reduction, a high reduction for the small return period rainfall event of penetration was obtained by applying permeable pavements instead of impermeable pavement. With the SWMM analysis results, it was proved that changing to permeable pavement is one of the ways to effectively provide water circulation to various green infrastructure projects, and for stormwater management in urban watersheds.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.211-218
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• 2014

In the design of reinforced rectangular concrete beam structure, the minimum amount of flexural reinforcement is required to avoid brittle failure. KCI code is based on concept of ultimate strength and usually used as a model code. But bridge design code enacted by Ministry of land, transportation and maritime affairs in 2012 is based on concept of limit state and similar to Euro code EN 1992-2. This means that the minimum reinforcement presented in both design codes has different origination and safety margin. When rectangular concrete beams with minimum reinforcement are designed according to EN and KCI codes, the amount of minimum reinforcement specified in EN code is only 76% of that in KCI code. This makes the design engineers to be confused. In this study, flexural tests were conducted on nine beams with the two different minimum reinforcement specified in KCI and EN design codes. In results, the measured ratios of nominal strength to crack strength from the test were about 25% greater than those evaluated from the equations presented in KCI and EN codes. The EN beams having only 76% of the minimum reinforcement for the KCI beams were fractured by rupture of steel reinforcement but in ductile manner. It is confirmed that the minimum reinforcement concrete beams designed according to both codes have enough safety margin in flexural capacity and moreover in ductility.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.681-688
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• 2020

Approximately 6,000 chemicals are transported through the sea, including hazardous and noxious substances (HNS), which cause marine pollution and are harmful to marine life. The HNS discharged into the sea during the maritime transportation process undergoes physical and chemical changes on the sea surface and in seawater, and some types of HNS sink and are deposited on the seabed. The HNS deposited on the seabed adversely affects the benthic ecosystem, and hence, it is desirable to detect, treat, and recover the HNS on the seabed. Therefore, this study was conducted to analyze the performance requirements that should be considered as the top priority when developing a mechanical system for recovering the HNS deposited on the seabed. Various types of existing dredging devices used for collecting and recovering pollutants from river beds and seabeds were investigated, and 10 performance indices for the mechanical devices were selected. The new performance requirements for the development of the seabed-deposited HNS recovery system were proposed using performance indices. By considering the depth of water in domestic seaports, some of the performance requirements of the mechanical system for recovering deposited HNS from the seabed were obtained as follows: production rate (50-300 ㎥/hr), maximum operation depth (50 m), sediment type (most forms), percentage of solids (10 % or higher), horizontal operating accuracy (±10 cm), limiting currents (3-5 knots). These performance requirements are expected to be useful in the conceptual and basic design of mechanical systems for recovering seabed-deposited HNS.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.6
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• pp.689-697
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• 2020

Hazardous and noxious substances (HNS) may cause maritime incidents during marine transportation, which are liable to lead to a large amount of spillage or discharge into the sea. The damage to the marine environment caused by the HNS spill or discharge is known to be much greater than the damage caused by oil spill. Particularly dangerous is HNS, which is deposited or buried in the seabed, as it can damage the organisms that live on, in, and near the bottom of the sea, the so-called "benthos," forming the benthic ecosystem. Therefore, it is vital that the HNS deposited on the seabed be recovered. In order to do so, procedures and equipment are required for accurate detection, stabilization treatment, and recovery of HNS in subsea sediment. Thus, when developing a mechanical recovery system, the performance requirements should be selected using performance indices, and the conceptual design of the mechanical recovery system should be based on performance requirements decided upon and selected in advance. Therefore, this study was conducted to arrive at a conceptual design for a mechanical recovery system for the recovery of HNS deposited on the seabed. In the design of the system, based on the fundamental scenario, the method of suction foundation with the function of self enclosing was adopted for recovering the HNS sediment in the subsea sediment. The mechanical recovery system comprises the suction foundation, pollution prevention, a pump system, control system, monitoring device, location information device, transfer device, and tanks. This conceptual design is expected to be reflected and used in the basic design of the components and shapes of the mechanical recovery system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.39-46
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• 2020

Accident prevention is more important than follow-up, which is based on Heinrich's law. The marine incident system is a very meaningful system that can prevent similar accidents, and was introduced in 2010 in Korea in accordance with the enforcement of the Code for the Investigation of Marine Casualties and Incidents (CI Code). Based on the CI Code, ship owners or ship operators are required to notify the Central Chief Inspector using the designated notification form in the event of a marine incident, but the number of voluntary notifications is still small. In this regard, this study intends to provide a direction for improvement by conducting an in-depth analysis focusing on the lack of notification procedures and forms of the marine incident system. To this end, we analyzed related regulations, cases of excellent overseas shipping countries such as the United Kingdom and Singapore, cases of similar domestic transportation systems such as aviation and railways, and marine incident notification procedures and forms of leading shipping companies. Major improvements in the notification process include the transition of the marine incidents to voluntary reporting, the expansion of the reporting subjects, and the identification of the security of the informer's identity. The main contents of the notification form revision include the use of the term "reporting" instead of "notification," the content of the identity guarantee in the notification form, and the increase in statistical value through the expansion of optional entries.

• Journal of Navigation and Port Research
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• v.26 no.1
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• pp.22-27
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• 2002

The 25 Watt hybrid MIC SSPA has been developed in the frequency rang from 1.6265 GHz to 1.6465 GHz for uplink of INMARST's earth station. To simplify the fabrication process, the whole system is designed of two parts composed of a friving amplifier and a power amplifier. The Motorolas MRF-6401 is used for driving part, the Motorolas MRF-16006 and MRF-16030 is used the power amplifier. We reduced weight and volume of high power amplifier through arranging the bias circuits in the same housing. The realized SSPA has more than 30 dB for gain within 20 MHz bandwidth, and the voltage standing wave ratios(VSWR) of input and output port are less than 1.7, respectively. The output power of 44 dBm is achieved at the 1 dB gain compression point of 106365 GHz These results reveal a high power amplifier of 25 Watt which is the design target. The Proposed SSPA manufacture techniques in this paper can be applied to the implementation of high power amplifiers for some radars and SCPC.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.216-221
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• 2017

Diesel engines have the highest brake thermal efficiency among internal combustion engines. Therefore, they are utilized in medium and large transportation vehicles requiring large amounts of power such as heavy trucks, ships, power generation systems, etc. However, diesel engines have a disadvantage of generating large quantities of nitrogen oxides during the combustion process. Therefore, the authors tried to reduce the amount of nitrogen oxides in marine diesel engines using a wet-type exhaust gas cleaning system utilizing the undivided electrolyzed seawater method. In this method, electrolyzed seawater in injected into the harmful gas discharge from the diesel engine using real seawater. The authors investigated the reduction of NO and NOx from the pH value, available chlorine concentration, and the temperature of electrolyzed seawater. The results of this experiment indicated that when the electrolyzed seawater is acidic, the NO oxidation rate in the oxidation tower is higher than that when the electrolyzed seawater has a neutral pH. Likewise, the NO oxidation rate increased with the increase in concentration of chlorine. Further, it was confirmed that the electrolyzed seawater temperature had no effect on the NO oxidation rate. Thus, the NOx exhaust emission value produced by the diesel engine was reduced by means of electrolyzed seawater treatment.

• The Journal of Industrial Distribution & Business
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• v.9 no.6
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• pp.77-85
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• 2018

Purpose - The purpose of this study is to subdivide trade transaction-centered structure in a logistics/distribution industry system to apply blockchain, to establish and resolve with which types of technology, and to provide policy direction of government institution and technology to apply blockchain in this kind of industry. Research design, data, and methodology - This study was conducted with previous researches centered on cases applied in various industry sectors on the basis of blockchain technology. Results - General fields of blockchain application include digital contents distribution, IoT platform, e-Commerce, real-estate transaction, decentralized app. development(storage), certification service, smart contract, P2P network infrastructure, publication/storage of public documents, smart voting, money exchange, payment/settlement, banking security platform, actual asset storage, stock transaction and crowd funding. Blockchain is being applied in various fields home and abroad and its application cases can be explained in the banking industry, public sector, e-Commerce, medical industry, distribution and supply chain management, copyright protection. As examined in the blockchain application cases, it is expected to establish blockchain that can secure safety through distributed ledger in trade transaction because blockchain is established and applied in various sectors of industries home and abroad. Parties concerned of trade transaction can secure visibility even in interrupted specific section when they provide it as a base for distributed ledger application in trade and establish trade transaction model by applying blockchain. In case of interrupted specific section by using distributed ledger, blockchain model of trade transaction needs to be formed to make it possible for parties concerned involved in trade transaction to secure visibility and real-time tracking. Additionally, management should be possible from the time of contract until payment, freight transfer to buyers through land, air and maritime transportation. Conclusions - In order to boost blockchain-based logistics/distribution industry, the government, institutionally, needs to back up adding legal plan of shipping, logistics and distribution, reviewing standardization of electronic switching system and coming up with blockchain-based industrial road maps. In addition, the government, technologically, has to support R&D for integration with other high technology, standardization of distribution industry's blockchain technology and manpower training to expand technology development.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.2
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• pp.123-129
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• 2012

Cabotage means transportation of cargoes or passengers between two points within same country by vessel or aircraft which registered to foreign country. Cabotage regulation has justified by the protectionism in economic aspect and by national security in the defence of a country, thus most world's major countries including United States of America, Japan and European Union(outside EU) are executing cabotage. Even though Korean's controlled fleet ranked to 5th in the world, shortage and ageing of Korean domestic seafarers came to the restricted factor in the Korean domestic shipping. Resultingly Korean government permitted 530 Myanmarese and Indonesian seafarers to come on board in domestic vessel. In regarding to the Korean law, there are no direct relationship between boarding foreign crew in domestic vessel. However the baxic concept of cabotage will be spoiled by boarding foreign crew under the regulation of cabotage, so special treatment should be needed to cover the problems in coastal shipping arose form them. To minimize the problems derived from foreign crew, following actions are recommended; first, management skills of foreign crew are needed to overcome differences of communication and culture; second foreign crew supporting center should be established to counsel their difficulties; third, high level of manning companies should be promoted; forth, stabilized crew supply should be guaranteed by improving employment condition; finally, memorandum of understanding should be concluded between two countries to prevent seceders.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.303-309
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• 2005

Olive flounder (Paralichthys olivaceus) is the major mariculture fish in Korea. The annual aquaculture production of olive flounder in Korea during the period of 2003 was 300,000 ton (2002 Statistics, Ministry of Maritime Affairs & Fisheries, Korea Government). Anesthetics is very necessary in aquaculture to minimize stress and damage during harvesting, grading, transportation, spawning induction and handling to fish. In the present study, isoeugenol as new anesthetic in marine fish, especially olive flounder, was examined to know the efficacy and proper concentration. As a result, olive flounder adult was exhibited sedation at 5 ppm at 10 and $15^{\circ}C$, and 7.5 ppm at $20^{\circ}C$, respectively. Anesthesia was required at least 10, 7.5 and 10 ppm at $10^{\circ}C$, $15^{\circ}C$ and at $20^{\circ}C$, respectively. In case of fry, the effect of sedation was observed from 2.5 ppm at $10^{\circ}C$ and 5 ppm at 15 and $20^{\circ}C$, respectively. Anesthesia was observed from 2.5 ppm at $10^{\circ}C$, 5 ppm at 15 and $20^{\circ}C$, respectively. In acute toxicity test, it was impossible to explore $LD_{50}$ with the concentration of isoeugenol adult at $15^{\circ}C$ used, but over immersion volume of 15 ppm at $15^{\circ}C$ was observed mortality in fry. Based on the present study, isoeugenol was identified as a safe and active anesthetic to olive flounder.