• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.5
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• pp.676-683
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• 2023

The development of the egg, larvae, and juveniles of Acheilognathus macropterus from the Wicheon stream of Nakdonggang River was investigated for early life history characteristics. The fish used in the study were collected from Wicheon stream located in Bian-myeon, Uiseong-gun, Gyeongsangbuk-do. The fertilized egg was 1.88±0.09 mm (n=30) in long diameter and 1.34±0.06 mm (n=30) in short diameter. After fertilization at a water temperature of 20℃, the egg took 31 h and 40 min to hatch. Newly hatched larvae had an average total length of 3.92±0.13 mm (n=30) and possessed a yolk sac the mouth and anus were not developed. Twenty days after hatching, the postflexion larvae had an average total length of 8.08±0.29 mm (n=30), with the tail tip fully bent at 45° and began feeding. Thirty-three days after hatching, the number of fin stems reached an integer with an average total length of 15.0±1.08 mm (n=30). In this study, differences in the egg size, hatching time, melanophore development period, and distribution location were confirmed between A. macropterus and allied species.

• The Korean Journal of Applied Statistics
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• v.30 no.3
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• pp.363-376
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• 2017

The insurance market is saturated and its growth engine is exhausted; consequently, the insurance industry is now in a low growth period with insurance companies that face a fierce competitive environment. In such a situation, it will be an important issue to find the probability distributions that can explain the flow of insurance claims, which are the basis of the actuarial calculation of the insurance product. Insurance claims are generally known to be well fitted by lognormal distributions or Pareto distributions biased to the left with a thick tail. In recent years, skew normal distributions or skew t distributions have been considered reasonable distributions for describing insurance claims. Cooray and Ananda (2005) proposed a composite lognormal-Pareto distribution that has the advantages of both lognormal and Pareto distributions and they also showed the composite distribution has a higher fitness than single distributions. In this paper, we introduce new composite distributions based on skew normal distributions or skew t distributions and apply them to Danish fire insurance claim data and US indemnity loss data to compare their performance with the other composite distributions and single distributions.

• Journal of Distribution Science
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• v.13 no.5
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• pp.53-60
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• 2015

Purpose - The purpose of this paper is to shed light on the importance of the slope and curvature of the volatility curve implied in option prices in the KOSPI 200 options index. A number of studies examine the implied volatility curve, however, these usually focus on cross-sectional characteristics such as the volatility smile. Contrary to previous studies, we focus on time-series characteristics; we investigate correlation dynamics among slope, curvature, and level of the implied volatility curve to capture market information embodied therein. Our study may provide useful implications for investors to utilize current market expectations in managing portfolios dynamically and efficiently. Research design, data, and methodology - For our empirical purpose, we gathered daily KOSPI200 index option prices executed at 2:50 pm in the Korean Exchange distribution market during the period of January 2, 2004 and January 31, 2012. In order to measure slope and curvature of the volatility curve, we use approximated delta distance; the slope is defined as the difference of implied volatilities between 15 delta call options and 15 delta put options; the curvature is defined as the difference between out-of-the-money (OTM) options and at-the-money (ATM) options. We use generalized method of moments (GMM) and the seemingly unrelated regression (SUR) method to verify correlations among level, slope, and curvature of the implied volatility curve with statistical support. Results - We find that slope as well as curvature is positively correlated with volatility level, implying that put option prices increase in a downward market. Further, we find that curvature and slope are positively correlated; however, the relation is weakened at deep moneyness. The results lead us to examine whether slope decreases monotonically as the delta increases, and it is verified with statistical significance that the deeper the moneyness, the lower the slope. It enables us to infer that when volatility surges above a certain level due to any tail risk, investors would rather take long positions in OTM call options, expecting market recovery in the near future. Conclusions - Our results are the evidence of the investor's increasing hedging demand for put options when downside market risks are expected. Adding to this, the slope and curvature of the volatility curve may provide important information regarding the timing of market recovery from a nosedive. For financial product distributors, using the dynamic relation among the three key indicators of the implied volatility curve might be helpful in enhancing profit and gaining trust and loyalty. However, it should be noted that our implications are limited since we do not provide rigorous evidence for the predictability power of volatility curves. Meaning, we need to verify whether the slope and curvature of the volatility curve have statistical significance in predicting the market trough. As one of the verifications, for instance, the performance of trading strategy based on information of slope and curvature could be tested. We reserve this for the future research.

• Korean Journal of Environment and Ecology
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• v.19 no.4
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• pp.342-347
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• 2005

This study was carried out to examine the distribution and habitat of Bibarl snake (Sibynophis Collaris) from March 1998 to June 2005 in Jeju island, Korea. 5 individuals of Bibari snake were observed on northern part of JeJu, 1 individual on southern area and 2 individuals on western area during research period. As a result, it was revealed that Bibari snake was found on the whole of Jeju island. Its observation was made from May to October, especially frequent from May to July. The body length of adult Bibari snakes were $406{\~}452mm$ and its tail length $29+{\~}202mm. Considering of number and shape of supralabials and number of temporals, the characters of Bibari snake were similar to those of S. chinensis. Therefore it seems need to reconstruct taxonomic position of Bibari snake. From a vertical viewpoint of Mt. Halla, Biabri snake prefers to stay on the grassland 600m below the sea. Consequently, it Is suggested that grassland be well-reserved for the protection of Bibari snakes.

• Journal of Acupuncture Research
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• v.26 no.6
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• pp.91-100
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• 2009

Objectives : The objective of this study is to investigate Anti-nociceptive and anti-inflammatory effects of Clematidis Radix (CR) herbal-acupuncture on the test rats with induced acute pain. Methods : The effects of Clematidis Radix (CR)-distillates were investigated in three types of models with three different pain. Highly purified distillate of CR called CR herbal-acupuncture was injected to Zusanli ($ST_{36}$) acupoint. In the tail flick test, the CR herbal-acupuncture treatment did not show a significant effect of relieving acute pain. To investigate the anti-inflammatory effect of CR herbal-acupuncture, the second testing model'pain was induced by injecting formalin to its planter. For the last model, carrageenan was injected into tarsal joint. the medicinal effect of CR herbal-acupuncture was evaluated through the behavioral analyses such as licking time, weight distribution ratio and ankle circumference. Results : In the formalin test, the analgesic effect of CR herbal-acupuncture was more pronounced in the late phase (for 20 min after the early phase) than in the early phase (for the first 10 min post formalin injection). It was proven by weight distribution ratio testing and ankle edema testing that herbal-acupuncture of CR inhibited arthritis caused by the carrageenan. Conclusions : These results revealed that CR herbal-acupuncture was effective to alleviate the inflammatory pain and could be used as an analgesic treatment with an anti-inflammatory effect.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.3
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• pp.88-97
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• 2012

To measure the traffic pollutants with high temporal and spatial resolution under real conditions, a mobile emission laboratory (MEL) was designed. The equipment of the mini-van provides gas phase measurements of CO, NOx, CO2 and THC (Total hydrocarbon), and number density & size distribution measurements of fine and ultra-fine particles by a fast mobility particle sizer (FMPS) and a condensation particle counter (CPC). The inlet sampling port above the bumper enables the chasing of different type of vehicles. This paper introduces the technical details of the MEL and presents data from the experiment in which a MEL chases a city bus fuelled by diesel, DME and Bio-diesel. The dilution ratio was calculated by the ratio of ambient NOx and tail-pipe NOx. Most particles from the bus fuelled by diesel were counted under 300 nm and the peak concentration of the particles was located between 30 and 60 nm. However, most particles in the exhaust of the bus fuelled by DME were nano-particles (diameter: less than 50 nm). The bus fuelled by Bio-diesel shows less particle emissions compare to diesel bus due to the presence of the oxygen in the fuel.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.9
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• pp.1159-1165
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• 2010

Glucose is the main energy source for mammalian cells and its absorption is co-mediated by two different families of glucose transporters, sodium/glucose co-transporters (SGLTs) and facilitative glucose transporters (GLUTs). Here, we report the cloning and tissue distribution of porcine GLUT2. The GLUT2 was cloned by RACE and its cDNA was 2,051 bp long (GenBank accession no. EF140874). An AAATAA consensus sequence at nucleotide positions 1936-1941 was located upstream of the poly $(A)^+$ tail. Open reading frame analysis suggested that porcine GLUT2 contained 524 amino acids, with molecular weight of 57 kDa. The amino acid sequence of porcine GLUT2 was 87% and 79.4% identical with human and mouse GLUT2, respectively. GLUT2 mRNA was detected at highest level in porcine liver, at moderate levels in the small intestine and kidney, and at low levels in the brain, lung, muscle and heart. In the small intestine, the highest level was in the jejunum. In conclusion, the mRNA expression of GLUT2 was not only differentially regulated by age, but also differentially distributed along the small intestine of piglets, which may be related to availability of different intestinal luminal substrate concentrations resulting from different food sources and digestibility.

• Journal of Labour Economics
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• v.40 no.4
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• pp.1-31
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• 2017

Recent empirical studies highlight the importance of between-firm or between-establishment factors in rising wage inequality. Examining the establishment-level data from the Mining and Manufacturing Survey of 2000-14, this paper finds that overall between-establishment wage dispersion has increased in Korea. However, unlike other OECD countries, the divergence occured in the lower tail of the wage distribution. Dispersion in labor productivity exhibits a similar movement, therefore explains the widening wage dispersion. In contrast, the link between wages and total factor productivity is much weaker, which appears to be associated with inefficient capital reallocation. I also find much heterogeneity in the productivity-wage relationship across productivity distribution. The most productive establishments turn the smallest portion of productivity gains into wage increases.

• Journal of The Korean Astronomical Society
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• v.53 no.2
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• pp.49-57
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• 2020

We present numerical simulations of decaying hydrodynamic turbulence initially driven by solenoidal (divergence-free) and compressive (curl-free) drivings. Most previous numerical studies for decaying turbulence assume an isothermal equation of state (EOS). Here we use a polytropic EOS, P ∝ ρ^γ, with polytropic exponent γ ranging from 0.7 to 5/3. We mainly aim at determining the effects of γ and driving schemes on the decay law of turbulence energy, E ∝ t^-α. We additionally study probability density function (PDF) of gas density and skewness of the distribution in polytropic turbulence driven by compressive driving. Our findings are as follows. First of all, we find that even if γ does not strongly change the decay law, the driving schemes weakly change the relation; in our all simulations, turbulence decays with α ≈ 1, but compressive driving yields smaller α than solenoidal driving at the same sonic Mach number. Second, we calculate compressive and solenoidal velocity components separately and compare their decay rates in turbulence initially driven by compressive driving. We find that the former decays much faster so that it ends up having a smaller fraction than the latter. Third, the density PDF of compressively driven turbulence with γ > 1 deviates from log-normal distribution: it has a power-law tail at low density as in the case of solenoidally driven turbulence. However, as it decays, the density PDF becomes approximately log-normal. We discuss why decay rates of compressive and solenoidal velocity components are different in compressively driven turbulence and astrophysical implication of our findings.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.4
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• pp.317-322
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• 1982

The biting behaviors of tuna were studied based on the remains of saury (Cololabis saira), which was used as bait, in the stomach contents of tuna. The saury remains were classified into four segmental groups (A-segment: Whole fish; B-segment: anterior partion with head: C-segment: middlepart without both head and tail: D-segment : posterior part without head). The tuna stomachs were independently named and grouped into three subsamples according to bait segments remaining in the stomach. The subsamples have the extra number of the stomach-naming segments and the distributions of the bait tegments are biased from tile random distribution. The distribution of the bait segments except the extra segments are hypothetically assumed to be random, and was subjected to the chi-square test of significance. The inferred conclusions are as follows:1. Most of the tuna having the B-segment had previously taken the C and/or D-segment. 2. The catchability of the yellowfin tuna having the B-segment seems higher than that of the fish having the A-segment in the stomach. 3. Tuna which had two or more bait heads should have taken the extra bait heads without being hooked detaching the head from the hook by biting the Posterior porting of tile bait.