• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.5
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• pp.671-681
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• 2014

The distribution and abundance of coastal fish species in Asan Bay, Korea, were estimated from hydroacoustic survey and net catches. Acoustic data were collected with 38 and 200 kHz from July to October of 2012, and converted to the nautical area scattering coefficient (NASC, $m^2/mile^2$) for $0.25n{\cdot}mile$ along ten transects. Japanese anchovy Engraulis japonicus was the dominant specie in the net catches. The virtual echogram technique was used to distinguish E. japonicus from other species based on the differences in the mean volume backscattering strength (${\Delta}MVBS$) at 38 and 200 kHz. Engraulis japonicus and other fishes are mainly distributed in the center channel and outer part of Asan Bay. E. japonicus tends to move from inner to outer Asan Bay in summer and fall. From NASC data, the target strength and length-weight function of E. japonicus and other fishes were used to estimate the E. japonicus stock at 24.1-93.3 tons, and other fish at 40.6-88.4 tons from July to October 2012. The estimated anchovy biomass compared well with the cumulative catch weight from stow net catches. The hydroacoustic method offers an approach to understanding spatial/temporal structure and estimating the biomass of fish aggregations in coastal areas.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.16 no.4
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• pp.246-253
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• 2011

In this study, we investigated the effect of freshwater discharge on benthic community in Nakdong estuaries. The sediment was dominated by sand except few channels where heterogenetic sediment composition was observed. Sediment composition was rarely affected by freshwater discharge during the rainy season; however, organic content in the sediment slightly increased after the rainy season. Macrobenthic species composition differed spatially. For instance, species composition decreased after the rainy season near the barrage. Benthic community analysis revealed three groups, in which the first group was found between barrage and sand bars located at the mouth of estuary, the second group was observed outside the sand bars, and the last group was found in the channel. Opportunistic benthic species indicative of organic pollution, such as Sinocorophium sinensis, Magelona japonica, and Heteromastus filiformis, dominated areas close to the barrage. Organic pollution by freshwater discharge appears to be responsible for the emergence of opportunistic benthic species, and this influenced areas from the mouth of bay to sand bars. Outside the sand bars, freshwater discharge did not seem to have affected species composition.

• Journal of Navigation and Port Research
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• v.38 no.3
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• pp.253-259
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• 2014

Traffic risks in fairway and harbour area increase lately according to be a sharpe change of ship's size and speed. It becomes hot issue to design a fairway, which's width is important to lower traffic risk and ensure navigational safety. The current design making a fairway and width do not focus on maneuvering motion of a large ship, but traffic risks are clear on reflecting the design of fairway, specially on width. To contact with these problems, this research proposes how to determine fairway' width in consideration of traffic volume. it suggests several situations of marine traffic congestion as like narrow channel and harbour area. here uses 162 simulations in MTS Ver.1 developed. Acquired simulation's results, environmental stress dates, figure in a model that relates with required fairway' width and allowable traffic volume. In added, suggested model compares current design with an width.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.10-17
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• 2013

History of Instream Flow Incremental Methodology (IFIM) Following the large reservoir and water development era of the mid-twentieth century in North America, resource agencies became concerned over the loss of many miles of riverine fish and wildlife resources in the arid western United States. Consequently, several western states began issuing rules for protecting existing stream resources from future depletions caused by accelerated water development. Many assessment methods appeared during the 1960's and early 1970's. These techniques were based on hydrologic analysis of the water supply and hydraulic considerations of critical stream channel segments, coupled with empirical observations of habitat quality and an understanding of riverine fish ecology. Following enactment of the National Environmental Policy Act (NEPA) of 1970, attention was shifted from minimum flows to the evaluation of alternative designs and operations of federally funded water projects. Methods capable of quantifying the effect of incremental changes in stream flow to evaluate a series of possible alternative development schemes were needed. This need led to the development of habitat versus discharge functions developed from life stage-specific relations for selected species, that is, fish passage, spawning, and rearing habitat versus flow for trout or salmon. During the late 1970's and early 1980's, an era of small hydropower development began. Hundreds of proposed hydropower sites in the Pacific Northwest and New England regions of the United States came under intensive examination by state and federal fishery management interests. During this transition period from evaluating large federal reservoirs to evaluating license applications for small hydropower, the Instream Flow Incremental Methodology (IFIM) was developed under the guidance of the U.S. Fish and Wildlife Service (USFWS).

• Journal of Radiation Protection and Research
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• v.39 no.4
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• pp.176-181
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• 2014

The object of this paper is to evaluate the fission product inventories and radiological doses in a non-LOCA event, based on the U.S. NRC's regulatory methodologies recommended by the TID-14844 and the RG 1.195. For choosing a non-LOCA event, one fuel assembly was assumed to be melted by a channel blockage accident. The Hanul nuclear power reactor unit 6 and the CE $16{\times}16$ fuel assembly were selected as the computational models. The burnup cross section library for depletion calculations was produced using the TRITON module in the SCALE6.1 computer code system. Based on the recently licensed values for fuel enrichment and burnup, the source term calculation was performed using the ORIGEN-ARP module. The fission product inventories released into the environment were obtained with the assumptions of the TID-14844 and the RG 1.195. With two kinds of source terms, the radiological doses of public in normal environment reflecting realistic circumstances were evaluated by applying the average condition of meteorology, inhalation rate, and shielding factor. The statistical analysis was first carried out using consecutive three year-meteorological data measured at the Hanul site. The annual-averaged atmospheric dispersion factors were evaluated at the shortest representative distance of 1,000 m, where the residents are actually able to live from the reactor core, according to the methodology recommended by the RG 1.111. The Korean characteristic-inhalation rate and shielding factor of a building were considered for a series of dose calculations.

• Atmosphere
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• v.20 no.2
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• pp.131-151
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• 2010

This study establishes a conceptual model to analyze heavy rainfall events in Korea using multi-functional transport satellite-1R satellite images. Three heavy rainfall episodes in two major synoptic types, such as synoptic low (SL) type and synoptic flow convergence (SC) type, are analyzed through a conceptual model procedure which proceeds on two steps: 1) conveyer belt model analysis to detect convective area, and 2) cloud top temperature analysis from black body temperature (TBB) data to distinguish convective cloud from stratiform cloud, and eventually estimate heavy rainfall area and intensity. Major synoptic patterns causing heavy rainfall are Changma, synoptic low approach, upper level low in the SL type, and upper level low, indirect effect of typhoon, convergence of tropical air in the SC type. The relationship between rainfall and TBBs in overall well resolved areas of heavy rainfall. The SC type tended to underestimate the intensity of heavy rainfall, but the analysis with the use of water vapor channel has improved the performance. The conceptual model improved a concrete utilization of images and data of satellite, as summarizing characteristics of major synoptic type causing heavy rainfall and composing an algorism to assess the area and intensity of heavy rainfall. The further assessment with various cases is required for the operational use.

• Proceedings of KOSOMES biannual meeting
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• 2005.05a
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• pp.37-43
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• 2005

Recently, many ships such as fishing boats, cargo ships, high speed ferry boats are visiting Mokpo harbor. In particular, many marine accidents rave been occurred at this area because of the narrow channel, a thick fog, the existing of the shallow waters etc. However there is no suitable ships' routeing system which takes account of today's traffic situations in this area. This study aims at the settling of hazardous factors to mitigate the danger to vessels in mokpo harbor and to secure the safety qf maritime environment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.2
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• pp.85-92
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• 2009

Polymer electrolyte membrane (PEM) fuel cells are a promising technology for short-term power generation required in residential and automobile applications. Proper management of water has been found to be essential for improving the performance and durability of PEM fuel cells. This study investigated the liquid water exhaust capabilities of various flow channels having different geometries and surface properties. Three-pass serpentine flow fields were prepared by patterning channels of 1 mm or 2 mm width onto hydrophilic Acrylic plates or hydrophobic Teflon plates, and the behaviors of liquid water in those flow channels were experimentally visualized. Computational fluid dynamics (CFD) simulations were also conducted to quantitatively assess the liquid water exhaust capabilities of flow channels for PEM fuel cells. Numerical results showed that hydrophobic flow channels have better liquid water exhaust capabilities than hydrophilic flow channels. Flow channels with curved corners showed less droplet stagnation than the channels with sharp corners. It was also found that a smaller width is desirable for hydrophobic flow channels while a larger width is desirable for hydrophilic ones. The above results were explained as being due to the different droplet morphologies in hydrophobic and hydrophilic channels.

• Journal of the Korea Society of Computer and Information
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• v.19 no.6
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• pp.37-48
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• 2014

Social emotion is being highlighted as an important factor of human life in terms of quality of communication as a variety of social networks are commonly used. To understand such social emotion, this study verifies and analyzes the significance of lexical meaning and expression of emotion basically for understanding of complex meaning of social emotion. The emotional expressions represented in SNS text messages, one of the major channel of communication, are examined in this study to create scales of meaning and expression and to understand the differences deeply. As a result of the analysis, it turned out that negative assessment factors were more than positive ones among social emotional factors while positive ones were outstandingly many in the case of social emotional expression. Social emotional factors were classified by basic emotional elements and valences while emotional expression included complex meaning and especially positive elements were dominant in general.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.202-216
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• 1999

The deep foundation is frequently used for the infrastructures. Since the quality control of the cast-in-place concrete foundations such as CIP piles and slurry walls is not so easy as that of the ready made PC(prestressed concrete) piles, it is necessary to get the information on the integrity of the concrete of the foundation. The depth estimation of foundations whose depths are unknown is also very important in repair and reinforcement works or in safety inspection and assessment to the big structures. The cross-hole sonic logging(CSL) system and the single channel reflection seismic measurement system were developed to test the integrity of pile. The former is well applied to CIP structures, while the later to all kinds of piles with less accurate result compared to that of CSL. To estimate the depth of the deep foundations, parallel seismics, borehole RADAR, and borehole magnetics can be used.