• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.311-321
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• 2007

The diffuse attenuation coefficient for down-welling irradiance $K_d({\lambda})$, which is the propagation of down-welling irradiance at wavelength ${\lambda}$ from surface to a depth (z) in the ocean, and underwater visibility are important optical parameters for ocean studies. There have been several studies on $K_d({\lambda})$ and underwater visibility around the world, but only a few studies have focused on these properties in the Korean sea. Therefore, in the present study, we studied $K_d({\lambda})$ and underwater visibility around the coastal area of the Yellow Sea, and developed $K_d({\lambda})$ and underwater visibility algorithms for ocean color satellite sensor. For this research we conducted a field campaign around the Yellow Sea from $19{\sim}22$ September, 2006 and there we obtained a set of ocean optical and environmental data. From these datasets the $K_d({\lambda})$ and underwater visibility algorithms were empirically derived and compared with the existing NASA SeaWiFS $K_d({\lambda})$ algorithm and NRL (Naval Research Laboratory) underwater visibility algorithm. Such comparisons over a turbid area showed small difference in the $K_d({\lambda})$ algorithm and constants of our result for underwater visibility algorithm showed slightly higher values.

• Journal of The Geomorphological Association of Korea
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• v.20 no.3
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• pp.41-53
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• 2013

This research was carried out to classify erosion shapes and sea-cliff erosion rates were estimated through periodic field survey in Dundu-ri, Anmyeondo. Based on the results of field measurements using the datum-point, the annual sea-cliff erosion rate was estimated about 25~102cm/yr by point. The erosion rate gradually increases from spring to summer, but tends to decrease slightly in autumn. Specifically, the erosion rate between June and July indicated a rather decreasing trend, but showed a sharp increase between July and September. This was attributed to erosion that proceeds more rapidly than during other periods due to severe rainstorms in summer that had a direct impact on the study area as well as storm surges caused by hurricanes. Afterwards, the sea-cliff erosion rate gradually decreased in autumn, but reflected an increasing trend again from December to January. This was attributed to the mechanical weathering that actively progresses as bed rocks on the sea-cliff undergo repeated freezing and thawing in winter. The seacliff in Dundu-ri is divided into three types according to the erosion shape. First, Type A is observed in the sea-cliff composed of the same bed rocks and hard rock stratum. Second, Type B is found in the sea-cliff with a relatively gentler slope compared to Type A, since weathering material including soil is formed on the surface of the sea-cliff consisting of the same bed rocks and hard rock stratum. Lastly, Type C is observed in the sea-cliff where hard rock stratum is mixed with soft rock stratum. In this case, the soft rock stratum slumps and erodes first by precipitation and wave energy, followed by additional slumping of the exposed hard rock stratum.

• Tunnel and Underground Space
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• v.29 no.5
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• pp.332-345
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• 2019

Maximum dip vector of individual joint plane, which can be uniquely defined on the hemispherical projection plane, has been established by considering its dip and dip direction. A new stereographic projection method for the rock slope analysis which employs the maximum dip vector can intuitively predict the failure modes of rock slope. Since the maximum dip vector is uniquely projected on the maximum dip point of the great circle, the sliding direction of discontinuity plane can be recognized directly. By utilizing the maximum dip vector of discontinuity both the plane sliding and toppling directions of corresponding blocks can be discerned intuitively. Especially, by allocating the area of high dip maximum dip vector which can form the flanks of sliding block the potentiality for the formation of virtual sliding block has been estimated. Also, the potentiality of forming the triangular-sectioned sliding block has been determined by considering the dip angle of joint plane the dip direction of which is nearly opposite to that of the slope face. Safety factors of the different-shaped blocks of triangular section has been estimated and compared to the safety factor of the most hazardous block of rectangular section. For the wedge analysis the direction of crossline of two intersecting joint planes, which has same attribute of the maximum dip vector, is used so that wedge failures zone can be superimposed on the stereographic projection surface in which plane and toppling failure areas are already lineated. In addition the maximum dip vector zone of wedge top face has been delineated to extract the wedge top face-forming joint planes the orientation of which provides the vital information for the analysis of mechanical behavior of wedge block.

• Economic and Environmental Geology
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• v.52 no.5
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• pp.347-356
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• 2019

Various studies regarding the sedimentary environment, depositional age, provenance, and metamorphic history have been carried out on the Taean Formation in the western part of Gyeonggi Massif, since the unique detrital zircon age pattern was revealed. This review paper introduces the previous researches on the Taean Formation and discusses the depositional age and provenance. The Taean Formation was traditionally regarded as a Precambrian stratigraphic unit, but recently it is interpreted to be a middle or upper Paleozoic formation due to the occurrence of large amounts of Early to Middle Paleozoic detrital zircons. The Taean Formation consists of metasandstone, argillaceous schist, and phyllite which are mainly made up of quartz and mica. The protoliths are interpreted as turbidites deposited in deep sea fan environment. The Taean Formation has been interpreted to be deposited between the Devonian to Triassic ages given the age differences between detrital zircons and intrusive rocks. There are two opinions that the deposition age is close to the Devonian or the Permian period. The provenance of this formation is supposed to be South China block, Chinese collisional belt, or Gyeonggi Massif. Given the available detrital zircon ages of the Taean Formation and other Korean (meta)sedimentary rocks, the Taean Formation shares major source rocks with Yeoncheon Group and Pibanryeong Unit of the Okcheon Supergroup, but their source regions are not entirely consistent. Considering the existing hypotheses about the depositional timing and provenance, we put weight on the possibility that the Taean Formation was deposited between Permian and Early Triassic periods. However, further studies on the stratigraphy and sedimentary petrology are needed to clarify its definition and to elucidate the provenance.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.5
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• pp.355-363
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• 2009

Double cropping system of oilseed crops introduced rape and castor bean was studied in the newly reclaimed tidal land of Korea. Surface soil EC to reach at 50% of growth reduction to the tallest height of crops was estimated $4dS\;m^{-1}$ for castor bean and $6dS\;m^{-1}$ for rape by logarithmic function. The castor bean cultivated during rainy summer much more suffered serious growth and yield reduction by flooding damage in the Hwaong and Yeonsangang reclaimed lands having low soil conductivity and finer textured soil than in the Iweon reclaimed land having higher soil conductivity and coarse sandy textured soil. Rape cultivated during dry winter-spring much more suffered serious growth and yield reduction by high soil salinity come from re-salting process. 50% yield reduction was estimated at $2.0\;2.5dS\;m^{-1}$ of surface soil EC by logarithmic function. Consequentially, it was concluded that oilseed production for energy by double cropping system of rape and castor bean might be possible under good controling soil salinity below $4dS\;m^{-1}$ for castor and $3dS\;m^{-1}$ for rape in the newly reclaimed land of Korea.

• International Area Studies Review
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• v.20 no.1
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• pp.23-51
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• 2016

This study analyzed the expected economic effects of the Korea-GCC FTA and sought strategies for industrial cooperation. To see the economic effects of Korea-GCC FTA, we analysed the effect of the oil tariff reduction of economy by Vector Autoregression(VAR) model. The estimation results shows that following the abolishment of the tariff on crude oil imports, GDP, GNI and consumption are expected to grow by 0.212%, 0.389% and 0.238%, respectively. Meanwhile, investment, export and import are estimated to drop by 0.462%, 0.413% and 0.342%, respectively. As for prices, producer prices are to rise by 6.356%p, whereas consumer prices fall by 2.996%p. In short, the Korea-GCC FTA and resultant abolishment of the tariff on crude oil imports followed by the decline in crude oil prices will result in declining prices whilst macroeconomic indices, such as GDP, GNI and consumption, will increase exerting positive effects on domestic economic growth. Also, it is necessary to proactively respond to GCC member states' industrial diversification policies for FTA-based industrial cooperation to diversify the sources of crude oil and natural gas imports for further resource risk management.

• Journal of Korea Water Resources Association
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• v.51 no.12
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• pp.1229-1235
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• 2018

We have examined dynamic relationships among water-efficiency, economic growth, electricity generation, and $CO_2$ emissions in Korea using various time-series analysis methods for 1990-2014. While previous studies have been limited to economic growth, $CO_2$ emissions, and electricity generation, this study contributed to explain the relationship between existing variables and water-efficiency. We find that the four variables reach a balanced state in the long run through short-term adjustment, $CO_2$ emissions and economic growth are responsible for water efficiency, and that $CO_2$ emissions, economic growth and water efficiency are the causes of electricity generation. The long-term impact coefficient estimates on water-efficiency show that the increase in electricity generation and the decrease in $CO_2$ emissions increase water-efficiency. Although economic growth has increased water-efficiency, moreover, we have identified an inverted U-shaped relationship between economic growth and water-efficiency, which suggests that economic growth above a certain level reduces the rate of increase in water-efficiency.

• Environmental and Resource Economics Review
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• v.28 no.2
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• pp.231-276
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• 2019

This paper analyzed the impact of the penetration of EV(electric vehicle) and FCEV(fuel cell electric vehicle) into the automobile industry, using a static CGE approach. There are contrasting view on the economic impact of EV/FCEV penetration: negative economic impact due to shrunken intermediate inputs versus positive impact because of input saving technical progress. Regarding environment, there is no clear consensus whether EV or FCEV will contribute to the reduction of $CO_2$ emissions in Korea. This study attempts to provide an answer to these questions. By giving shocks to the input coefficients of automobile industries and automobile using sectors, as well as to the final demands for energies. we integrated the Bass diffusion model into the CGE framework, The result suggests that the EV penetration has adverse impact on the $CO_2$ emission while the FCEV penetration has positive impact. On the other hand, both EV and FCEV have positive impacts on GDP. When considering automobile manufacturing sectors only, adverse impacts on $CO_2$ are demonstrated both for EV and FCEV. However, since the size of $CO_2$ increase is small, these results does not alter the overall effects.

• Korean journal of applied entomology
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• v.57 no.4
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• pp.287-295
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• 2018

A meridic artificial diet, including whole milk powder, wheat bran, maize leaf powder, and sucrose as the main nutrients, was tested for rearing Locusta migratoria (Orthoptera: Acrididae). When locusts were supplied with only the artificial diet over their entire life cycle, a second generation was not produced. The same result was observed when the diet was supplied daily and fresh maize leaves were supplied every other day. However, when the diet and fresh maize leaves were supplied alternately every other day, four generations of L. migratoria were produced. Fecundity in adults reared with the alternating diet was higher than that in adults supplied with both the diet and maize leaves daily. These results indicate that this artificial diet could be used as a supplementary food for rearing of L. migratoria.

• Journal of Navigation and Port Research
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• v.43 no.3
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• pp.143-152
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• 2019

In this paper, the towing stability of the LNG bunker barge was estimated. Currently, LNG bunkering barge is being developed for the bunkering of LNG (Liquefied Natural Gas), an eco-friendly energy source. Since the LNG bunkering barge assumes the form of a towed ship connected to the tow line, the towing stability of the LNG bunker barge is crucial f not only for the safety of the LNG bunker barge but also the neighboring sailing vessels. In the initial stages, a numerical code for towing simulation was developed to estimate the towing stability of the LNG bunkering barge. The MMG (Maneuvering Mathematical modeling Group) model was applied to the equations of motion while the empirical formula was applied to the maneuvering coefficients for use in the initial design stage. To validate the developed numerical code, it was compared with published calculation and model test results. Towing simulations were done based on the changing skeg area and the towing position of the LNG bunkering barge using the developed numerical codes. As a result, the suitability of the designed stern skeg area was confirmed.