• The Journal of the Convergence on Culture Technology
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• v.8 no.3
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• pp.485-491
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• 2022

The traditional economic order quantity (EOQ) model is analyzed under the basic assumption that the purchase price is paid immediately upon receiving the product. However, product suppliers may allow a certain period of deferral of payment for product purchase costs in order to differentiate themselves from competitors. From the distributor's point of view, such a credit transaction can temporarily divert product purchase costs, resulting in a reduction in inventory investment costs, and ultimately, a factor that lowers the selling price for the purpose of increasing end-customer demand can be. In addition, in that credit transactions are provided for the purpose of increasing the demand of suppliers as a means of differentiation from competitors, it is more general to be allowed flexibly according to the transaction volume. In this regard, assuming that the end customer's demand is represented by a linear decreasing function of the distributor's selling price, this study analyzes a model for determining the distributor's pricing and ordering policies under order-size-dependent delay in payments. For the analysis, we also assume that the inventory is depleted not only by customer's demand but also by decaying.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.493-499
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• 2023

Trade credit refers to a transaction where a product supplier allows an distributor to defer payment for a certain period of time for the purchase cost of the products. This practice is generally permitted as a means of differentiation between competing companies. Such trade credit is commonly granted based on the volume of transactions, aiming to increase customer orders. From the perspective of the distributor, trade credit allows for a deferred payment period for the purchase cost, leading to cost savings in inventory investment. These cost savings in inventory investment can be a factor in reducing selling prices with the aim of increasing customer demand. In this study, we analyze a model that determines the optimal selling price and order quantity from the perspective of the distributor, assuming that the supplier allows a deferred payment period dependent on the transaction volume. We assume that the final customer's annual demand exhibits an exponential decrease with respect to the distributor's selling price, using a constant price elasticity function. To analyze the problem, we assume that the product deteriorates at a constant rate over time and aim to establish an inventory model for the intermediate distributor. We also want to analyze the impact of deterioration on the inventory policies of the intermediate distributor.

• Information Systems Review
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• v.24 no.4
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• pp.119-142
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• 2022

Organizations are attempting a digital transformation that converts physical business processing into virtual business processing. Through this digital transformation, organizations are overcoming time and space constraints and creating competitiveness. The digital transformation of this work environment has been accelerated as many organizations have implemented remote work due to the recent COVID-19 pandemic. This study focused on business process virtualizability, which is the result of the rapid digital transformation of the work environment. Business process virtualizability is the resulting quality, such as the suitability or excellence of business processing in a virtual environment. This research model is the effect of process, IT and organizational characteristics on business process virtualizability. As a result of the verification of people who have experienced remote work in a virtual environment, first, it was confirmed that, in terms of process characteristics, sensory requirements affect business process virtualizability, but relationship requirements, synchronism requirements, and identification and control requirements do not. Second, in terms of IT characteristics, it was confirmed that representation and reach affect business process virtualizability. Third, it was confirmed that, in terms of organizational characteristics, job autonomy affects business process virtualizability, but evaluation unfairness does not. This study found that representation and reach of IT had the most significant influence on business process virtualizability, job autonomy was next, and sensory requirements had the lowest influence. This presents practical implications for organizations to increase the success potential of business process virtualizability.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.265-277
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• 2000

Laboratory experiments were conducted to investigate characteristics for removing ammonia-nitrogens by electrolysis methods. A stainless steel plate is used as the cathode and either $IrO_2{\backslash}Ti$ plate serves as the anode. Experiments were conducted to examine the effects of the operating conditions, such as the current density, retention time, electrode gap, $Cl^-/NH_4{^+}-N$ on the $NH_4{^+}-N$ removal efficiency. Possible optimum range for these operating variables are experimentally determined. The $NH_4{^+}-N$ removal efficiencies between plate type anode and net type anode were about same effect, but electrolytic power using net type anode is low than plate type anode. The $Cl^-/NH_4{^+}-N$ ratio was about $20.0kgCl^-/kgNH_4{^+}-N$ when $NH_4{^+}-N$ removal obtained 73 %, $Cl^-/NH_4{^+}-N$ ratio needs $27.6kgCl^-/kgNH_4{^+}-N$ so as to $NH_4{^+}-N$ completely remove. The removal efficiency of $NH_4{^+}-N$ increase with current density, retention time and $Cl^-/NH_4{^+}-N$ ratio, but decreased with increasing electrode gap. The relationship of operating conditions and $NH_4{^+}-N$ removal efficiencies are $$NH_4{^+}-N_{re}(%)=14.5364(Current\;density)^{0.7093}{\times}(HRT)^{1.0060}{\times}(Gap)^{-0.9926}{\times}(Cl^-/NH_4{^+}-N)^{1.0024}$$ With adding COD or/and alkalinity, relationships are $$NH_4{^+}-N_{re}(%)=9.8408(Current\;density)^{0.6232}{\times}(HRT)^{1.0534}$$ There existed a competition between the removals for $NH_4{^+}-N$ and $COD_{Cr}$ during electrolysis, the removal of $NH_4{^+}-N$ was shown to be dominant. $NH_4{^+}-N$ removal was high as addition of glucose and alkalinity.

• Journal of the Korean Vacuum Society
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• v.14 no.2
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• pp.78-83
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• 2005

Nanometric crystalline silicon (no-Si) embedded in dielectric medium has been paid attention as an efficient light emitting center for more than a decade. In nc-Si, excitonic electron-hole pairs are considered to attribute to radiative recombination. However the surface defects surrounding no-Si is one of non-radiative decay paths competing with the radiative band edge transition, ultimately which makes the emission efficiency of no-Si very poor. In order to passivate those defects - dangling bonds in the $Si:SiO_2$ interface, hydrogen is usually utilized. The luminescence yield from no-Si is dramatically enhanced by defect termination. However due to relatively high mobility of hydrogen in a matrix, hydrogen-terminated no-Si may no longer sustain the enhancement effect on subsequent thermal processes. Therefore instead of easily reversible hydrogen, phosphorus was introduced by ion implantation, expecting to have the same enhancement effect and to be more resistive against succeeding thermal treatments. Samples were Prepared by 400 keV Si implantation with doses of $1\times10^{17}\;Si/cm^2$ and by multi-energy Phosphorus implantation to make relatively uniform phosphorus concentration in the region where implanted Si ions are distributed. Crystalline silicon was precipitated by annealing at $1,100^{\circ}C$ for 2 hours in Ar environment and subsequent annealing were performed for an hour in Ar at a few temperature stages up to $1,000^{\circ}C$ to show improved thermal resistance. Experimental data such as enhancement effect of PL yield, decay time, peak shift for the phosphorus implanted nc-Si are shown, and the possible mechanisms are discussed as well.

• Korean Journal of Organic Agriculture
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• v.16 no.1
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• pp.127-142
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• 2008

This study was carried out to germination characteristics by temperature conditions and allelopathic effects of aqueous extracts on Amaranthus spinosus L. in order to investigate the competitive dominant in plant ecosystem and possibility application of natural herbicide. A. spinosus L. sprouted after 24 hour from seeding in $30{\sim}45^{\circ}C$ treatment. The germination ratio of A. spinosus L. was the highest estimated at 63.3(${\pm}2.9$)% in $40^{\circ}C$ treatment, followed by 33.3(${\pm}2.9$)% in $35^{\circ}C$, 1.7(${\pm}2.9$)% in $30^{\circ}C$ and 5.0(${\pm}0.0$)% in $45^{\circ}C$ treatment. It was generally decreased the Relative Germination Ratio(RGR), the Relative Elongation Ratio(RER), the Relative Fresh weight Ratio(RFR) of receptor plants by the aqueous extracts of concentration of A. spinosus L. but it was differently inhibited the kind of receptor plant species. And it was different effected among growing regions that aqueous extracts of concentration of A. spinosus L. inhibited more root than shoot. The total phenolic compounds content of A. spinosus L. was decreased gradually middle, first and last of growth stage, and gradually decreased to leaves, roots and stems. We think that A. spinosus L. appeared high germination ratio at a short period and showed allelopathic effects on other plants. Therefore A. spinosus. L. hold the competitive dominant of plant ecosystem in Jeju Island and possibility application of natural herbicide.

• Neonatal Medicine
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• v.17 no.2
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• pp.181-192
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• 2010

Purpose: Current studies have demonstrated the neuroprotective effects of dizocilpine (MK-801) in many animal models of brain injury, including hypoxic-ischemic (HI) encephlopathy, trauma and excitotoxicity, but limited data are available for those during the neonatal periods. Here we investigated whether dizocilpine can protect the developing rat brain from HI injury via anti-apoptosis. Methods: In an in vitro model, embryonic cortical neuronal cell culture of Sprague-Dawley (SD) rats at 18-day gestation was done. The cultured cells were divided into three groups: normoxia (N), hypoxia (H), and hypoxia treated with dizocilpine (HD). The N group was prepared in 5% $CO_2$ incubators and the other groups were placed in 1% $O_2$ incubators (94% N2, 5% $CO_2$) for 16 hours. In an in vivo model, left carotid artery ligation was done in 7-day-old SD rat pups. The animals were divided into six groups; hypoxia (N), hypoxia (H), hypoxia with sham-operation (HS), hypoxia with operation (HO), HO treated with vehicle (HV), and HO treated with dizocilpine (HD). Hypoxia was made by exposure to a 2 hour period of hypoxic incubator (92% N2, 8% $O_2$). Results: In the in vitvo and in vivo models, the expressions of Bcl-2 in the hypoxia groups were reduced compared to the normoxia group. whereas those in the dizocilpine-treated group were increased compared to the hypoxia group. However. the expressions of Bax and caspase-3 and the ratio of Bax/Bcl-2 were revealed reversely. Conclusion: Dizocilpine has neuroprotective property over perinatal HI brain injury via anti-apoptosis.

• The Korean Journal of Malacology
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• v.15 no.1
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• pp.31-39
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• 1999

This study was aimed to describe the population dynamics and secondary production of Tapes philppinarum on Chohwa and Toksan tidal flats in Kwangyang Bay, from June 1994 to July 1995. The size distributions in shell length showed bimodal patterns from June 1994 to April 1995. Thereafter the distribution changed to the passage of time, indicating an increase in shell length. The mean densities decreased gradually with month. Chohwa A sustained highestdensity, followed by Chohwa B, Toksan C, and Toksan D. The recruitment of new year class occurred first on the upper tidal flat, and then moved to the lower tidal flat. The mean biomass in flesh dry weight of each year class increased in spring just before the spawning period, and thereafter decreased progressively. Annual mean biomass wasrecorded as 170.7 g m$\^$-2/ at Chohwa A, 220.7 g m$\^$-2/ at Chohwa B, 21.8 g m$\^$-2/ at Toksan C, and 45.2 g m$\^$-2/ at toksan D. Annual productions of Ruditapes philippinarum were estimated as 259.72 g m$\^$-2/ yr$\_$-1/ at Chohwa A, 359.79 g m$\^$-2/ yr$\_$-1/ at Chohwa B, 45.02 g m$\^$-2/ yr$\_$-1/ at Toksan c, 68.88 g m$\^$-2/ yr$\_$-1/ at Toksan D. Annual productions were much higher on Chohwa tidal flat than those on Toksan tidal flat. While P:B ratio were higher on Toksan tidal flat as 1.70 than those on Chohwa tidal flat as 1.58. In conclusion, the Chohwa tidal flat showed higher biomass and producion of Ruditapes philippinarum, whereas the Toksan tidal flat showed higher P:B ratio. The total amount of potential food might influence on the density, biomass nad produciton, whereas the amount of food and space per individual might influence on the growth rate and P:B ratio.

• Korean Chemical Engineering Research
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• v.50 no.1
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• pp.18-24
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• 2012

Lignocellulose is difficult to hydrolyze due to the presence of lignin and the technology developed for cellulose fermentation to ethanol is not yet economically viable. However, recent advances in the extremely new field of biotechnology for the ethanol production are making it possible to use of Agriculture residual biomass, e.q., Barley straw, because of their several superior aspects as Agriculture residual biomass; low lignin, high contents of carbohydrates. Barley straw consists of 39.78% cellulose (glucose), 22.56% hemicelluloses and 19.27% lignin. Pretreatment of barley straw using NaOH pretreatment solutions concentration with 2%, temperature $85^{\circ}C$ and reaction times 1 hr were investigates. $NH_4OH$ pretreatment condition was solutions concentration with 15%, temperature $60^{\circ}C$, and reaction times 24hr were investigates. Furthermore, enzymatic saccharification using cellulose at $50^{\circ}C$, pH 4.8, 180 rpm for conversion of cellulose contained in barley straw to monomeric sugar. The pretreatment of barley straw using NaOH and $NH_4OH$ can significantly improve enzymatic saccharification of barley straw by extract more lignin and increasing its accessibility to hydrolytic enzymes. The result showed NaOH pretreatment extracted yield of lignin was 24.15%. $NH_4OH$ pretreatment extracted yield of lignin was 29.09%. Shaccharification of barley straw pretreatment by NaOH for 72hr and pH 4.8 result in maximum glucose concentration 15.39g/L (58.40%) and by $NH_4OH$ for 72hr and pH 4.8 result in maximum glucose concentration 16.01g/L (64.78%).

• Food Science and Preservation
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• v.24 no.1
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• pp.68-73
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• 2017

The main objective of this study was to investigate the effects of various commercial pectin enzyme treatments on juice yield from Aronia fruits (Aronia melanocarpa) as well as changes in physicochemical properties such as pH, total acid, reducing sugar, soluble solid, total anthocyanin, total phenolic compounds, and DPPH radical scavenging activity. Different types and reaction conditions of pectinase were also investigated in order to improve extraction yield of Aronia juice. The optimal conditions of enzyme treatment were 0.1% of concentration (w/w) at $50^{\circ}C$ for 120 min. Among enzymes used in this study, extraction yield with Rapidase Press L treatment from Aronia juice was the highest and resulted in a significant increase in juice from 51.0 to 69.1%. Rapidase C80 MAX showed 68.83% extraction yield while Plantase TCL showed 66.70% extraction yield. Reducing sugar and soluble solid contents increased after enzyme treatment. Total acids also slightly increased after enzyme reaction. No significant difference was observed in pH regardless of pectin enzyme treatment. However, enzyme treatment resulted in an increase in total phenolic compounds, total anthocyanin, and DPPH radical scavenging in Aronia juice compared to the juice prepared juice.