• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.14 no.3
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• pp.175-187
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• 2010

This paper presents the numerical valuation of the two-asset step-down equitylinked securities (ELS) option by using the operator-splitting method (OSM). The ELS is one of the most popular financial options. The value of ELS option can be modeled by a modified Black-Scholes partial differential equation. However, regardless of whether there is a closedform solution, it is difficult and not efficient to evaluate the solution because such a solution would be represented by multiple integrations. Thus, a fast and accurate numerical algorithm is needed to value the price of the ELS option. This paper uses a finite difference method to discretize the governing equation and applies the OSM to solve the resulting discrete equations. The OSM is very robust and accurate in evaluating finite difference discretizations. We provide a detailed numerical algorithm and computational results showing the performance of the method for two underlying asset option pricing problems such as cash-or-nothing and stepdown ELS. Final option value of two-asset step-down ELS is obtained by a weighted average value using probability which is estimated by performing a MC simulation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.5
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• pp.809-815
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• 1997

A series of experiments were conducted to study effects of osmolality and $Ca^{2+}$ on sperm motility in marbled sole, Limanda yokohamae. Spermatozoa were immotile when the milt was mixed with solutions (electrolyte or non-electrolyte) of lower osmolality than the average seminal plasma osmolality (351 mOsm/kg), but became motile after mixing milt with an hyperosmotic solution. However, with the osmolality above 1,639 mOsm/kg spermatozoa ceased their movement. When the milt was suspended in the $Ca^{2+}$ free artificial seawater (ASW) containing ethylenglycoltriamine (EGTA), the percentage of motile spermatozoa decreased in proportion to the increase of EGTA. Most spermatozoa were quiescent in a medium containing 3 mM EGTA. The motility of spermatozoa prevented by 3 mM EGTA was recovered by the subsequent addition of $Ca^{2+}$ over the concentration of 0.25 mM. Effects of calmodulin antagonist, trifluoperazin (TFP) on spermatozoa were examined to elucidate the possible functions of calmodulin in sperm motility. TFP immobilized spermatozoa 5n ASW at the concentration of 0.5 M. These findings suggest that calcium is an effective external factor in the initiation process of sperm motility.

• Economic and Environmental Geology
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• v.56 no.1
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• pp.55-63
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• 2023

Variations in geochemical and mineralogical properties of the ferromanganese(Fe-Mn) crust reflect environmental changes. In the present study, geochemical and mineralogical analyses, including micro X-ray fluorescence and X-ray diffraction, were utilized to reconstruct the paleo-ocean environment of western Pacific Magellan seamount cluster. Samples of the Fe-Mn crust were collected using an epibenthic sledge from the open seamount XX (151° 51.12' 7.2" E and 16° 8.16' 9.6" N, 1557 meters below sea level) in the Western Pacific Magellan Seamount. According to the structure and phosphating status, the Fe-Mn crust of the OSM-XX can be divided into the following: phosphatizated (L4-L5), massive non-phosphatizated (L3), and porous non-phosphatizated (L1-L2) portions. All ferromanganese layers contain vernadite, and owing to the presence of carbonate fluorapatite (CFA), the phosphatizated portion (L4-L5) is rich in Ca and P. The massive non-phosphatizated section (L3) contains high Mn, Ni, and Co, whereas the porous non-phosphatizated portion (L1-L2), which comprises detrital quartz and feldspar, is rich in Fe. Variations in properties of the Fe-Mn crust from the OSM-XX reflect changes in the nearby marine environment. The formation of this crust started at approximately 51.87 Ma, and precipitation of the CFA during the global phosphatization event that occurred at approximately 36-32 Ma highlights an elevated sea level and low temperature during the associated period. The high Mn, Ni, and Co concentrations and elevated Mn/Fe ratios of samples from the massive phosphatizated portion indicate that the oxygen minimum zone (OMZ) was enhanced, and reducing conditions prevailed during the crust formation. The high Fe and low Mn/Fe ratios in the porous portion indicate a weak OMZ and dominantly oxidizing conditions. These data reflect environmental changes following the end of the Mi-1 glacial period in the Miocene-Oligocene boundary. Subsequently, Mn/Fe and Co/Mn ratios increased slightly in the outermost part of Fe-Mn crust because of the enhanced bottom current and OMZ associated with the continued cooling from approximately 9 Ma. However, the reduced carbonate dissolution rate in the Pacific Ocean from approximately 6 Ma decreased the growth rate of the Fe-Mn crust.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.22 no.1
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• pp.75-89
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• 2018

This paper presents the numerical valuation of the arithmetic Asian option by using the operator-splitting method (OSM). Since there is no closed-form solution for the arithmetic Asian option, finding a good numerical algorithm to value the arithmetic Asian option is important. In this paper, we focus on a two-dimensional PDE. The OSM is famous for dealing with plural-dimensional PDE using finite difference discretization. We provide a detailed numerical algorithm and compare results with MCS method to show the performance of the method.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.145-151
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• 2007

Hypertonicity (hypernatremia) of extracellular fluid causes water movement out of cells, while hypotonicity(hyponatremia) causes water movement into cells, resulting in cellular shrinkage or cellular swelling, respectively. In most part of the body, the osmolality of extracellular fluid is maintained within narrow range($285-295 mOsm/kgH_2O$) and some deviations from this range are not problematic in most tissue of the body except brain. On the other hand, the osmolality in the human renal medulla fluctuates between 50 and $1,200 mOsm/kgH_2O$ in the process of urine dilution and concentration. The adaptation of renal medullary cells to the wide fluctuations in extracellular tonicity is crucial for the cell survival. This review will summarize the mechanisms of urine concentration and the adaptation of renal medullary cells to the hyper tonicity, which is mediated by TonEBP transcription factor and its target gene products(UT-A1 urea transporter etc.).

• Development and Reproduction
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• v.15 no.2
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• pp.151-158
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• 2011

The comparison of the chemical properties of semen of black porgy Acanthopagrus schlegelii long-term acclimated reared in freshwater (BFW) and seawater (BSW) with sperm activity of salinity and ion composition. The chemical properties of seminal plasma on BFW of the factors that most there was not significant difference in the BSW. However, osmolality in seminal plasma of BFW and BSW was $307.0{\pm}4.6$ and $337.3{\pm}10.1$ mOsm/kg, respectively, where BFW showed significant lower concentration in contrast to BSW. Salinity effect on sperm motility of BFW and BSW in 0 psu solution, no sperm motility was observed, whereas in 10 psu solution, both BFW and BSW sperms showed low motility and short time post sperm activation. However, diluted in 20 and 32 psu solutions, highest motility and long time post sperm activation were observed in BFW and BSW sperm. SAI of BFW and BSW varied in depend on the osmolality regardless of ion kind and it showed the highest value in the similar osmolality of artificial seawater (956 mOsm/kg). Accordingly, even in sperm released from BFW, factors initiating sperm motility are determined by osmolality.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.3
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• pp.310-316
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• 1999

Physiological responses (cortisol, glucose, GPT, GOT, total protein, hematocrit, sodium, chloride, potassium, total calcium and osmolality), growth and survival rates of grey mullet (Mugil cephalus) and Nile tilapia (Oreochromis niloticus) by the manipulation of salinity were studied. Salinity was increased directly from freshwater to $33\%_{\circ}$ and remained for 15 days. Then, salinity was decreased directly from seawater to freshwater and remained for other 15 days. All tilapias were dead at the third day, but $96.5\%$ of grey mullet were survived at the 30th day. The grey mullet showed no significant differences for cortisol and glucose concentrations in the seawater and freshwater. However, those of the Nile tilapia were increased in seawater. The grey mullet showed no significant differences for sodium, chloride and potassium concentrations during experimental period. However, those of the Nile tilapia were significantly increased when exposed to seawater. The osmolality of grey mullet ranged between 293.5 mOsm/kg and 335.0 mOsm/kg for the whole experimental period.

• Journal of Microbiology and Biotechnology
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• v.23 no.11
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• pp.1560-1568
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• 2013

Salmonella, a main cause of foodborne diseases, encounters a variety of environmental stresses and overcomes the stresses by multiple resistance strategies. One of the general responses to hyperosmotic stress is to import or produce compatible solutes so that cells maintain fluid balance and protect proteins and lipids from denaturation. The ProP and ProU systems are the main transport systems for compatible solutes. The OsmU system, recently identified as a third osmoprotectant transport system, debilitates excessive growth as well by reducing production of trehalose. We studied a fourth putative osmoprotectant transport system, YehZYXW, with high sequence similarity with the OsmU system. A Salmonella strain lacking YehZ, a predicted substrate-binding protein, did not suffer from hyperosmolarity but rather grew more rapidly than the wild type regardless of glycine betaine, an osmoprotectant, suggesting that the YehZYXW system controls bacterial growth irrespective of transporting glycine betaine. However, the growth advantage of ${\Delta}yehZ$ was not attributable to an increase in OtsBA-mediated trehalose production, which is responsible for the outcompetition of the ${\Delta}osmU$ strain. Overexpressed YehZ in trans was capable of deaccelerating bacterial growth vice versa, supporting a role of YehZ in dampening growth. The expression of yehZ was increased in response to nutrient starvation, acidic pH, and the presence of glycine betaine under hyperosmotic stress. Identifying substrates for YehZ will help decipher the role of the YehZYXW system in regulating bacterial growth in response to environmental cues.

• Journal of Embryo Transfer
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• v.15 no.2
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• pp.121-128
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• 2000

This study was conducted to enhance the efficiency of embryo transfer and embryos produced in vitro according to select good quality blastocyst among in vivo or in vitro produced embryos. After middle blastocys(MB) and late blastocyst(LB) stages embryos that developed in vitro for 7∼8 days were treated hypertonic solution(380 mOsm or 600 mOsm) and the rate of development to hatched blastocyst(HB) was examined. The results obtained were summarized as follows: The proportion of embryos developed to HB was higher than that of control regardless of hypertonic solution treatment. However, it was related to culture time in hypertonic solution The propotrion of embryos developed to HB of morphologically recovered embryos in 380 nOsm solution ws higher than that of morphologically shrinked embryos. However, treatment time was not significantly different the rates of HB development. Especially, the proportion of embryos developed to HB of morphologically recovered embryos of the 30-min-treated group was significantly higher than that of control (p<0.05). The results suggest that hypertonic solution treatment should enhance the efficiency for criterion of transferable blastocyst quality.

• Atmosphere
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• v.28 no.2
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• pp.211-222
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• 2018

Cloud droplet activation process is well described by $K{\ddot{o}}hler$ theory and several parameterizations based on $K{\ddot{o}}hler$ theory are used in a wide range of models to represent this process. Here, we test the two different method of calculating the solute effect in the $K{\ddot{o}}hler$ equation, i.e., osmotic coefficient method (OSM) and ${\kappa}-K{\ddot{o}}hler$ method (KK). To do that, each method is implemented in the cloud droplet activation parameterization module of WRF-CHEM (Weather Research and Forecasting model coupled with Chemistry) model. It is assumed that aerosols are composed of five major components (i.e., sulfate, organic matter, black carbon, mineral dust, and sea salt). Both methods calculate similar representative hygroscopicity parameter values of 0.2~0.3 over the land, and 0.6~0.7 over the ocean, which are close to estimated values in previous studies. Simulated precipitation, and meteorological variables (i.e., specific heat and temperature) show good agreement with reanalysis. Spatial patterns of precipitation and liquid water path from model results and satellite data show similarity in general, but on regional scale spatial patterns and intensity show some discrepancy. However, meteorological variables, precipitation, and liquid water path do not show significant differences between OSM and KK simulations. So we suggest that the relatively simple KK method can be a good alternative to the OSM method that requires various information of density, molecular weight and dissociation number of each individual species in calculating the solute effect.