• Korean Journal of Fisheries and Aquatic Sciences
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• v.43 no.1
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• pp.83-88
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• 2010

Acoustic telemetry is a useful method to investigate fish behavior and is widely used to obtain biological information. In this study, the detection ability of a mooring-type acoustic telemetry system and the seasonal changes were studied for survey design and data analysis. The system detection range was examined with an underwater noise model, and seasonal changes were estimated with a ray-tracing program and underwater temperature profile data. The field experiment was conducted with two sets of pingers and six receivers to estimate the difference in detection rate by installation depth and to compare the model estimate. Results indicated that the long-range detection ability of the acoustic telemetry system was significantly affected by underwater temperature. The detection rate rapidly decreased near the sea surface or bottom despite that the near-range Signal to noise ratio was sufficient.

• Korean Journal of Agricultural Science
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• v.38 no.3
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• pp.571-581
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• 2011

This study develops a mid-term preceding observation model of radish to complement an existing short-term agricultural observation model. The first purpose of the study is to extend a three seasonal classification(spring, summer, fall) of fruit-vegetables to a four seasonal classification that involves the winter additionally. This allows us to verify the reason for demand and supply unbalance and unstable price of radish. The second purpose is to construct a mid-term preceding observation model that would be used to forecast planted areas, output, monthly shipment and price. To achieve these purposes, several multiple regression models are estimated. A system is consisted of a planted areas equation, a yield equation, monthly shipment distribution equation, and monthly price equation. To calculate output an auxiliary equation is involved in the system and the consumer price index etc are considered as exogenous variables.

• Proceedings of the KSRS Conference
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• 1998.09a
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• pp.89-94
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• 1998

Seasonal variation of attenuation coefficient spectra in Japan sea was extracted from underwater radiance/irradiance spectra observed by a moored buoy system developed by National Space Development Agency of Japan (NASDA). The buoy was deployed 9 months from August 31, 1996 to June 1, 1997. Throughout this period, it was collecting downward irradiance and upward radiance spectra under water at the depth of 1.5m and 6.5m everyday. The dairy averaged diffused attenuation coefficient spectra and underwater reflectance spectra were calculated. The results were compared with the absorption spectra of filtered samples obtained by validation cruises, which carried out 5 times during the moored period. Also, the natural fluorescence of chlorophyll a were extracted from the upward radiance spectra observed at 1.5m depth. The seasonal variation of the calculated attenuation coefficient spectra and the natural fluorescence were examined. The result shows a weak blooming of phytoplankton on November and a large blooming on April.

• 한국해양학회지
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• v.19 no.1
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• pp.31-35
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• 1984

The seasonal variation of sea surface temperatures (SST) in the neighbouring seas of Korea was studied performing the harmonic analysis of the monthly mean SST data of 15 years (1961-1975) at 182 stations routinely collected by the Fisheries Research and Development Agency. The mean SST in the West Sea (Yellow Sea) is lower than that in the East Sea (Sea of Japan) whereas the annual range of SST in the West Sea is much larger than that in the East Sea. The maximum SST occurs between mid August and early September. The seasonal variation of SST in the seas of Korea is influenced by incoming radiation and heat advections by ocean currents and winds.

• Journal of the Korean Data and Information Science Society
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• v.19 no.4
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• pp.1037-1046
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• 2008

Recently, the oil suppliers who supply the tax-exempt oil to the fishery are confronted with big trouble in their supply and demand system due to the unstable global oil prices. We applied the seasonal ARIMA(SARIMA) model to the low-sulfur and high-sulfur crude oil which are in great request and developed forecasting systems for them. Since there are many parameters in SARIMA, it is difficult to estimate the optimal parameters, but it is overcome by using simulation looping program. In conclusion, we found that the obvious seasonality in demand of low-sulfur and these demands are tending downwards gradually.

• International Journal of Industrial Entomology and Biomaterials
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• v.4 no.2
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• pp.109-115
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• 2002

With the objective of selecting suitable breeding resource material, 10 polyvoltine and 10 bivoltine breeds were drawn from the germplasm collection of Central Sericultural Research and Training Institute, Mysore, and evaluated for 3 seasons comprising one year (6 trials). Data were collected on seven traits of economic importance such as fecundity, pupation rate, cocoon yield, cocoon weight, cocoon shell weight, cocoon shell ratio and filament length, and statistically analysed with two-way classification, Joint scoring method and evaluation index. Significant seasonal variations (P < 0.01) were observed in both polyvoltine and bivoltine breeds. Polyvoltines BL27, BL36 and BL54 and bivoltines CSR2, CSR4 and Daizo scored highest ranking values in all the three methods. Hybridization was initiated based on larval markings and cocoon shapes. Seasonal variations were discussed.

• Animal cells and systems
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• v.2 no.2
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• pp.165-176
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• 1998

Seasonal changes in microzooplankton abundance were identified in the mesohaline Chesapeake Bay and several tributaries from July 1992 through December 1995. Ciliates numerically dominated, comprising over 90% of the total microzooplankton density and aloricate ciliates usually outnumbered loricate ciliates. Copepod nauplii accounted for the highest microzooplankton biomass (>75% in dry weight). Rotifers made small contributions to the total microzooplankton density and biomass (<5%). Time series analysis indicated a twelve month cycle in microzooplankton abundance, and mid-summer(August) peaks for copepod nauplii, and a spring through fall peaks (May-October) for ciliates. Rotifers showed two seasonal peaks: one in mid-summer(August) at the river stations and the other in mid-winter(February) at the mesohaline stations. Seasonal peaks of copepod nauplii and rotifers coincided with the mesozooplankton abundance peak. On the other hand, ciliate maximum usually occurred between the phytoplankton and mesozooplankton peaks. This pattern of microzooplankton seasonality suggests the intermediate trophic role of microzooplankton (especially ciliates) between the phytoplankton(especially picophytoplankton) and mesozooplankton in Chesapeake Bay and its tributaries.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1298-1300
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• 2003

Based on the Leaf Area Index (LAI) data derived from remote sensing information and eco-climate data, the responses of regional ecosystem variations in seasonal and interannual scales to the East Asian monsoon are studied in this paper. It is found that the vegetation ecosystems of eastern China are remarkably correlated with the East Asian monsoon in seasonal and interannual scales. In the seasonal timescale, the obvious variations of the vegetation ecosystems occur with the development of the East Asian monsoon from the south in the spring to the north in the autumn. In the interannual scale, high LAI appears in the strong East Asian monsoon year, whereas low LAI is related to the weak East Asian monsoon year. These further lead to the characteristic of 'onsoon-driven ecosystem' in the eastern China monsoon region, which can be revealed by LAI.

• Journal of the korean society of oceanography
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• v.33 no.3
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• pp.41-52
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• 1998

A seasonal circulation pattern in the eastern Yellow Sea (EYS) is suggested from the water mass analysis and geostrophic calculation using the hydrographic data collected by National Fisheries Research and Development Institute during the years of 1970 to 1990. This research focuses on the presence of inflow of warm (and saline) waters into EYS in summer. EYS is divided into two regions in this paper: the west coast of Korea (WCK) and the central Yellow Sea (CYS). In CYS, waters are linked with warm waters near Cheju Island in winter, but with cold waters from the north in summer (in the lower layer). It is not simple to say about WCK because of the influences of freshwater input and tidal mixing. Nevertheless, water mass analysis reveals that along WCK, waters have the major mixing ratios (40-60%) of warm waters in summer, while the dominant mixing ratios (50-90%) of cold waters in winter. Such a seasonal change of water mass distribution can be explained only by seasonal circulation. In winter, warm waters flow northward into CYS and cold waters flow southward along WCK. In summer, warm waters flow northward along WCK and cold waters flow southward into CYS. This circulation pattern is supported by both statistical analysis and dynamic depth topography. Accordingly, Yellow Sea Warm Current may be defined as the inflow of warm waters to CYS in winter and to WCK in summer.

• Atmosphere
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• v.17 no.4
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• pp.421-433
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• 2007

We have investigated the seasonal characteristics of surface turbulent fluxes observed at Ieodo Ocean Research Station from 2005 to 2006. Both 10Hz and 30 minutes flux data are quality controled, and tilt correction is performed in 10Hz data before quality control. The turbulent fluxes of open sea shows clear seasonal variations, though diurnal variations are barely shown. The seasonal ratio of stable and unstable conditions are closely related to the temperature difference between sea surface and air. In stable and semi-stable condition, latent and sensible heat fluxes have very small values without any relationship with wind speed. Though friction velocity shows slightly increasing trend with wind speed, it has many outliers. In unstable condition, turbulent fluxes increased with wind speed. Especially, latent heat flux increased rapidly during DJF. The latent heat flux at high wind speeds is more scatter.