• Korean Journal of Construction Engineering and Management
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• v.16 no.5
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• pp.77-85
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• 2015

The Hedonic Pricing model is the predominant approach used today to model the effect of relevant factors on real estate prices. These factors include intrinsic elements of a property such as floor areas, number of rooms, and parking spaces. Also, The model also accounts for the impact of amenities or undesirable facilities of a property's value. In the latter case, euclidean distances are typically used as the parameter to represent the proximity and its impact on prices. However, in situations where multiple facilities exist, multi-colinearity may exist between these parameters, which can result in multi-regression models with erroneous coefficients. This research uses Variance Inflation Factors(VIF) and Ridge Regression to identify these errors and thus create more accurate and stable models. The techniques were applied to apartments in Guro-gu of Seoul, whose prices are impacted by subway stations as well as a public prison, a railway terminal and a digital complex. The VIF identified colinearity between variables representing the terminal and the digital complex as well as the latitudinal coordinates. The ridge regression showed the need to remove two of these variables. The case study demonstrated that the application of these techniques were critical in developing accurate and robust Hedonic Pricing models.

• KDI Journal of Economic Policy
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• v.14 no.4
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• pp.3-26
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• 1992

The pupose of this paper is to construct a price determination model of the Korean economy and to find out the propogation mechanism of monetary and fiscal policies. The model is a small-size macroeconometric model consisted of ten core equations : consumption, investment, exports, imports, consumer price index, wage rate, corporate bond rate, potential GNP, capital stock, and GNP identity. The model is a Keynesian model : consumer price index is determined by markup over costs, and wage rate is expressed by Phillipse curve ralation. Two features of the model, however, distinguish this model from other macroeconometric models of the Korean economy. First of all, the estimation of potential GNP and the capital stock is endogenized as suggested by Haque, Lahiri, and Montiel (1990). This allows us to calculate the level of excess demand, which is defined as the difference between the actual GNP and the potential GNP. Second, interest rate, inflation and wages are all estimated as endogenous variables. Moreover, all quantity variables include price variables as important determinants. For instance, interest rate is an important determinant of consumption and investment. Exports and imports are determined by the real effective exchange rate. These two features make the interactions between excess demand and prices the driving forces of this model. In the model, any shock which affects quantity variable(s) affects excess demand, which in turn affects prices. This strong interaction between prices and quantities makes the model look like a classical model over the long run. That is, increases in money supply, government expenditures, and exchange rate (the price of the U.S. dollar in terms of Korean won) all have expansionery effects on the real GNP in the short run, but prices, wage, and interest rate all increase as a result. Over the long run, higher prices have dampenning effects on output. Therefore the level of real GNP turns out to be not much different from the baseline level ; on the other hand, the rates of inflation, wage and interest rate remain at higher levels.

• Neonatal Medicine
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• v.18 no.1
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• pp.158-162
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• 2011

Preterm infants with oligohydramnios after preterm premature rupture of membranes can present with severe respiratory distress immediately after birth, and the most common cause is pulmonary hypoplasia. Unlike infants with pulmonary hypoplasia, some cases have shown dramatic improvement with aggressive ventilatory support during the initial 1-2 days of distress: those patients have been defined as having dry lung syndrome. It is assumed that oligohydramnios leads to functional pulmonary hypoplasia by compression of the fetal lungs: some of the improvement in dry lung syndrome may thus have resulted from inflation of compressed lung tissue and increase of lung compliance. We report two incidences of dry lung syndrome that were treated successfully with high inflation pressure and inhaled nitric oxide (NO): these are the first dry lung syndrome cases to be reported in Korean infants.

• Journal of the Korean Arthroscopy Society
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• v.6 no.1
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• pp.49-53
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• 2002

Purpose : To document the change in the temperature of the knee joint at the initiation and conclusion of an arthroscopic procedure and correlate this temperature change with other intra-operative variables. Material and Methods : Temperature measurements were performed in 40 consecutive patients(42 cases) that underwent arthroscopic surgery. Temperature measurements were taken at the initiation of the procedure, before and after inflation of the tourniquet. The last measurement was recorded at the end of the surgical procedure. Results : The mean knee joint temperature evaluated before inflation of the torniquet was $35.1{\pm}1.0$, at the end of surgery, $24.6{\pm}1.5^{\circ}C$. The mean temperature change observed from the beginning to the end of the procedure was $10.5^{\circ}C$. The student t test showed a statistically significant difference of the initial joint temperature(p<0.01) between the patient with no and+1 effusion / between the patient with no and +2 effusion. The temperature at the end of the procedure was found to be statistically low correlated (p<0.01) with the lower temperature of the irrigant and the lengthening of the arthroscopic procedure. Conclusion : Consideration should be given to maintaining the saline irrigant to more physiologic temperature to protect the articular cartilage from any possible temperature induced damages.

• Journal of Distribution Science
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• v.11 no.10
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• pp.73-79
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• 2013

Purpose - This study examines the impact of oil price volatility on economic activities in Korea. The new millennium has seen a deregulation in the crude oil market, which invited immense capital inflow into Korea. It has also raised oil price levels and volatility. Drawing on the recent theoretical literature that emphasizes the role of volatility, this paper attends to the asymmetric changes in economic growth in response to the oil price movement. This study further examines several key macroeconomic variables, such as interest rate, production, and inflation. We come to the conclusion that oil price volatility can, in some part, explain the structural changes. Research design, data, and methodology - We use two methodological frameworks in this study. First, in regards to the oil price uncertainty, we use an Exponential-GARCH (Exponential Generalized Autoregressive Conditional Heteroskedasticity: EGARCH) model estimate to elucidate the asymmetric effect of oil price shock on the conditional oil price volatility. Second, along with the estimation of the conditional volatility by the EGARCH model, we use the estimates in a VECM (Vector Error Correction Model). The study thus examines the dynamic impacts of oil price volatility on industrial production, price levels, and monetary policy responses. We also approximate the monetary policy function by the yield of monetary stabilization bond. The data collected for the study ranges from 1990: M1 to 2013: M7. In the VECM analysis section, the time span is split into two sub-periods; one from 1990 to 1999, and another from 2000 to 2013, due to the U.S. CFTC (Commodity Futures Trading Commission) deregulation on the crude oil futures that became effective in 2000. This paper intends to probe the relationship between oil price uncertainty and macroeconomic variables since the structural change in the oil market became effective. Results and Conclusions - The dynamic impulse response functions obtained from the VECM show a prolonged dampening effect of oil price volatility shock on the industrial production across all sub-periods. We also find that inflation measured by CPI rises by one standard deviation shock in response to oil price uncertainty, and lasts for the ensuing period. In addition, the impulse response functions allude that South Korea practices an expansionary monetary policy in response to oil price shocks, which stems from oil price uncertainty. Moreover, a comparison of the results of the dynamic impulse response functions from the two sub-periods suggests that the dynamic relationships have strengthened since 2000. Specifically, the results are most drastic in terms of industrial production; the impact of oil price volatility shocks has more than doubled from the year 2000 onwards. These results again indicate that the relationships between crude oil price uncertainty and Korean macroeconomic activities have been strengthened since the year2000, which resulted in a structural change in the crude oil market due to the deregulation of the crude oil futures.

• Archives of Plastic Surgery
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• v.37 no.1
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• pp.99-103
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• 2010

Purpose: Blow-out fractures are reduced through transcutaneous or transconjunctival incisions. But the field of orbital surgery is difficult due to lack of visualization of fracture site, blind dissection of orbital floor, susceptibility of injury of orbital structures. In these situations, the former technique of using an antral balloon catheter has advantages over other methods for reconstruction because of its rapidity, simplicity, and inexpensiveness. Furthermore, the antral balloon catheter allows not only elevation of the orbital bone fragment but also expansion of the maxillary sinus in cases where there is a fracture of its walls. But postoperative follow-up method using computed tomography is expensive. Hence, we report a simple and inexpensive follow-up method using radiopaque dye inflation. Methods: We performed endoscopic transantral approach in 5 cases of blow-out fracture under general anesthesia. To accomplish this technique, a rigid 4 mm, 0 or 30 degree angled endoscopy was inserted into the maxillary sinus. Inflation of the catheter started gradually, with 10 to 15 mL of saline mixed radiopaque dye (saline: dye, 5 : 1) by syringe and while observing the elevation of the fracture site with endoscope until a proper contour was reached. For the maintain of the position of fractured site, 12 French urinary balloon foley catheter were used in fracture site for 7 - 10 days. Results: Postoperative assessment was performed by means of clinical and simple radiographic examination to secure the catheter under the inferior orbital wall and in the maxillary sinus. No specific complications occurred related to this procedure. Results of the surgery and follow-up in all cases were satisfactory. Conclusion: It may be a better alternative to the conventional follow-up method, with less cost and effectiveness of the catheter patency. The advantages of using the urinary balloon foley catheter with the radiopaque dye include the following : it is safe, efficacy, simple, and especially low cost. On drawback of this method is the discomfort to the patient caused by the catheter during the treatment.

• KDI Journal of Economic Policy
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• v.14 no.2
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• pp.189-203
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• 1992

Any money model should address the most important phenomenon of a monetary economy, which is the phenomenon of the rate of return dominance. Even if the holding returns on financial or nonfinancial assets are higher than the rate of return on fiat money holding, which is typically zero, people still hold and use money. In a period of accelerating inflation, number of dominating assets increases continuously, yet people continue to hold and use money. Wallace's (1980) overlapping generations model cannot address the rate of return dominance phenomenon. His model does not capture the mediun of exchange role of fiat money. In this paper, an overlapping types model of fiat money is constructed, in which different types of consumers have different preferences on different types of goods, are endowed with different types of goods, are located at seperated regions, and live for only two periods. In this model, people hold and use money despite the dominating assets, even if inflation accelates. Money in this case serves as a pure medium of exchange, whereas in Wallace's model, money serves as a pure store of value, and money disappears if a dominating asset exists. An interesting feature of the overlapping types model presented in this paper is that money does not provide a cheap approximation to an idealized and efficient real allocation. A monetary economy is always superior to a nonmonetary economy, because money helps overcome the incompleteness of the overlapping types friction. In a monetary economy, however, a pareto optimal allocation cannot always be achieved, because money cannot always overcome the overlapping types friction itself. Therefore, with the criterion of optimality of real allocations, the monetary economy is more optimal than a nonmonetary economy but less optimal than a complete Arrow-Debreu economy. This feature has important implications on macro modelling. Because of the difficulty in introducing money into a macro model in an essential and endogenous manner as in the overlapping types model of this paper, a macro model typically ignores money and studies real allocations without the money factor. The possible inefficiencies of a monetary economy, relative to a complete real Arrow-Debreu economy, may indicate differences in real allocations between the two models.

• Korean Journal of Construction Engineering and Management
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• v.10 no.6
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• pp.146-153
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• 2009

The year 2008 was a hard year for Korea's construction companies. The real estate downturn resulted in halting new construction and stopping existing work, and inflation of global oil prices caused price hikes in rebar and concrete materials. As a solution to reducing the budget, the newly appointed government announced plans to increase low cost bid contracts from 10 billion to 30 billion won. When such economical and political factors negatively impact the construction market, projects based on low cost contracts are the hardest hit. Many problems already inherent in low cost bid contracts become accentuated. Consequently, this provides an opportune time to actually study and analyze the issues in these projects. This paper introduces the findings made from investigating four projects struggling to make ends meet in the year 2008. Results show that flow of cash (i.e., liquidity), or lack thereof, was the root cause which in turn was hampered by failed mechanisms for design changes, material inflation. Attributing cash flow risk to the bottom of the production structure (i.e., small business subcontractors) was also a problem within the industry. Contractors need a better way to prepare against material price fluctuations, and owners need to assist in expediting payment during times of extreme downturn.

• Journal of Legislation Research
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• no.44
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• pp.7-31
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• 2013

Paradigm of Global economy is changing to creative economy. This study focuses on the role of creative economy to clarify (understand clearly) the impact (influence) which transition of economy system will bring about. The creative economy is basically came from New economy theory. According to the New economy theory, a state can achieve sustainable growth without an inflation, or higher growth rate under given inflation rate, through an investment on ICT. However, different from America, Korea had limited effect of New Economy. This is because Korean economy had factor-input driven growth model rather than New Economy mechanism. However, ICT is essential requirement to move toward New Economy(Digital Economy), it does not sufficiently explain the increase of productivity and economic growth. A crucial point to realize New economy is how to diffuse and spill over the technology development on ICT sector to other industry. ICT is not creative industry or creative economy per se, and it should play as an enabler to improve other industry's productivity. The creative economy can be understood as an extension of New Economy theory. It means the economy that creates values by cultural assets and human resource, as well as capital and labor factors. However, if we understand the meaning of creative economy as change of input factors, it is hard to bring real shape of creative economy.

• Journal of Convergence for Information Technology
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• v.11 no.9
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• pp.94-108
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• 2021

This study is to identify the internal and external factors of a company that can affect the rate of change in the inventory turnover ratio. In addition, by appropriately managing or responding to these factors, changes in the inventory turnover ratio do not occur abruptly, so that the company's business and financial performance can be improved. To confirm this, factors such as gross profit margin, cash flow volatility, advertising expenses, inflation, exchange rate rise, and leading economic index were selected, and these factors were predicted to affect the change rate of inventory turnover. Data of 85,878 companies were obtained from domestic securities listings, KOSDAQ listings, and externally audited companies, and multiple regression analysis was performed using the data. Gross profit margin and cash flow volatility have a significant positive (+) effect, advertising expenses have a negative (-) significant effect, and inflation and exchange rate rises have a negative (-) significant effect. As an influence, the leading economic index was tested to have a significant positive (+) effect. Through this, it is suggested that manufacturing companies can improve their business performance and achieve operational efficiency by well understanding and appropriately managing factors that can affect the change rate of inventory turnover.