• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.1
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• pp.109-119
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• 2002

This study is to estimate that food waste bags with biodegradable plastic are really decomposed by microorganism in composting with food waste and to examinate how biodegradable plastic affects composting. 6 kinds of 30%, 4 kinds of 100% and 2 kinds of none biodegradable plastics were used in d1is study. In 30% biodegradable plastics the highest Degradation rare is 6% in meso-condition and 10% in thermal-condition. Srain at auto break decreased to 150% in meso-condition and 120% in thermal-condition. Stress at max load were also reduced to $180kgf/cm^2$ in mesocondition and $200kgf/cm^2$ in thermal-condition. Usually, LLDPE decreased larger than HDPE in physical characreristics but HDPE is higher in degradation rate. 1n stain at auto break and stress ar max load 100% biodegradable plastic declined to 230% and to $380kgf/cm^2$ in meso-condition and to 440% and to $400/cm^2$ in thermal-condition respectively. 100% biodegradable plastics showed higher biodegradation and decomposition then 30%. They appeared clearly through SEM observation. As a result, it was not appropriate to use 30% biodegradable plastics as food waste bag because they were not decomposed perfectly. It is possible to use 100% biodegradable plastic as it but cost is too high. So development of technique is needed.

• Journal of Global Scholars of Marketing Science
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• v.13
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• pp.71-88
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• 2004

Although the factors that affect the width of latitude of price acceptance is well documented, the attempt to develop a practice-oriented methodology to calibrate the region of price insensitivity (i.e., a latitude of price acceptance) for a given individual brand has been relatively rare. The researcher aims to try to full this gap by developing a conjoint analysis-based procedure that can be applied to many industries. Furthermore, we examine the difference in the latitude of price acceptance between on- and off-line transaction in stock industry in Korea. The conjoint analysis-based procedure was applied to measure the disaggregate price response curve for individual stock investment both on- and off line transaction channel. The curves from the samples enable us to estimate the individual choice probabilities corresponding to applied price points. Using t-test the differences in mean choice probabilities between the list price and another price point were tested, through which we can get the latitude of price acceptance for a given brand in stock market. These procedures were tested in on- and off-line stock market in South Korea. The results showed that investors on off-line channel have wider latitudes of price acceptance than the investors on on-line transaction system.

• Journal of Internet Computing and Services
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• v.18 no.4
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• pp.109-119
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• 2017

This paper is to analyse empirically using the data collected from Korea portal Naver's ad management system and show online ad platform may not be two-sided market. It is aim of this study to propose the appropriate approach to define the market, based on the empirical result. Here are two research questions to be reviewed. First, is there any consistency between business model of search advertising and definition of two-sided market which Rochet-Tirole proposed in 2006? Second, do indirect network externalities exist significantly in search advertising market? if so, this study is going to estimate the level of it through empirical measurement. Based on Luchetta's paper which suggested that google may be one-sided market, it performed the correlation & regression analysis to prove his suggestion. The result is that online search advertising costs increased by more than 50 won when advertisers increased by one unit. However, there was no significant correlation and regression between the search frequency and online search advertising cost. It means that there is little possibility to identify two-sidedness in online search advertising service(market) because of no(or little) indirect network externalities which are a necessary condition for two-sided market. This result has three implications, such as the availability to adapt traditional market definition tools to online search advertising market, the possibility enhancement to find the fundamental competition elements in defined market and promotion of the powers of persuasion in competitive market reality. It is significant that the gap between legal scholars including regulatory practitioners and economists can be overcome to some extent. who have shown the different perspective on the two-sided market.

• Korea Journal of Hospital Management
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• v.25 no.2
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• pp.45-56
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• 2020

Purpose: The purpose of this study is to investigate medical care behaviors influencing accuracy of the payment based New diagnosis-related groups (DRG) compared to fee for service (FFS) in hospitalized patients with medical illness. Methodology: In order to estimate the difference in medical costs between New DRG and FFS depending on medical care behaviors, medical records and hospital claims data (n=4,232) were utilized, which were collected from a single public hospital during the first-half of 2018. Data were analyzed by descriptive statistics, t-test, chi-square test, and multivariate binary logistic regression. Findings: The average difference in medical costs between New DRG and FFS were KRW 506,711±13,945 with incentives and KRW -51,506±12,979 without incentives, respectively. Forty-four point two percent (44.2%, n=1,872) of total subjects were shown to have negative compensation in overall medical costs with New DRG compared to the costs with FFS. Medical care behaviors that affected on the negative compensation were the presence of severe bed sores on admission, medical consultations, death, operations, medications and laboratory or imaging tests with unit price over KRW 100,000, hospital-acquired complications or underlying comorbidities, elderly patients (≧65 years), and hospitalized for more than average inpatient days defined by New DRG (p<0.001). The difference in average medical cost between New DRG and FFS for a group with mild illness was KRW -11,900±10,544, whereas it was KRW -196,800±46,364 for a group with severe illness (p<0.0001). Practical Implications: These findings suggest that New DRG payment model without incentives may incompletely cover the variation of medical costs in real clinical practice. Therefore, policy makers need to consider that the current New DRG reimbursement should be focused and refined to improve accuracy of payment on medical care resources utilized in severe and complex medical conditions.

• Korean Journal of Construction Engineering and Management
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• v.9 no.6
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• pp.137-146
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• 2008

Both competent authorities and private entrepreneurs face plenty of risks when negotiating BTO(Build Transfer Operation) methods of PPI(Private Participations in Infrastructures) projects. Also, success and failure of projects largely depend on the concession agreement contract. In this study, for more efficient negotiation, major issues are examined, and quantitatively analyzed to find out not only the relationship but also the characteristics of which these issues share. Questionnaire research was conducted through both research and by experts who were divided into an ordering agency, design company and constructor. Characteristics of major issues were quantitatively analyzed using the Likert index method, ANOVA(ANalysis of VAriance) and AHP(Analytic Hierarchy Process) analysis. Case studies were examined in order to estimate construction cost, rates of return, government finance support, level of operation-revenues guarantees, estimating operational costs and usage fees. With these 6 items, relative priority, relative impression which is sensible to risk and extent of difficulty in presenting data which is objective were quantitatively analyzed by the ordering agency, design company and constructor groups. From the analysis, there were some similarities between the design company and constructor groups while there was less of similarities between the ordering agency and design company or constructor. The government is diversifying the methods of project promotion, and PPI project from infrastructure-centered to public culture facilities are being expand. The current study will provide not only supporting efficient negotiation but also revitalizing PPI projects.

• Journal of the Korean Ceramic Society
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• v.39 no.2
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• pp.120-125
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• 2002

AC powder EL devices were fabricated by screen printing method with the dielectric materials in insulating layer and the electrical resistivity of rear electrode. Brightness and current density were measured at voltage range of 50∼300 $V_{rms}$ to estimate optoelectrical properties of AC powder EL devices, respectively. Frequency generator was used as system producing frequency and voltage of a sine wave. Brightness and current density were measured by luminometer and multimeter. Also, dielectric constant for dielectric layer was measured by impedance analyser after preparing thick film. Dielectric constant was improved with amount of $TiO_2$ to $BaTiO_3$ powder. By applying such a process to dielectric layer of low cost AC powder EL device, brightness was improved to 50 cd/$m^2$ at similar current density. Dielectric constant $BaTiO_3$ powder by solution combustion process is better than commercial $BaTiO_3$ powder. By applying to that of low power consumption AC powder EL device, brightness was improved to 85 cd/$m^2$. Brightness of AC powder EL device was relatively decreased by control of electrical resistivity of rear electrode, current density was also decreased.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.32-46
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• 2017

Recent rapid urban expansion and crowding of various industrial facilities has affected the features of a significant part of downtown area, resulting in areas having buildings with a wide range of height and the foothills. To compute a velocity pressure exposure coefficient, namely the design wind speed factor, this study defines ground surface roughness by utilizing concentration analysis for the height of each building. After obtaining spatial data by extracting a building layer from digital maps, the study area was partitioned for the concentration analysis and to allow investigation of the frequency distribution of building heights. Concentration analysis by building height was determined with the Variation-to-Means Ratio (VMR) and Poisson distribution analysis using a buildings distribution chart, with statistical significance determined using Chi-square verification. Applying geographic information systems (GIS) with the architectural information made it possible to estimate a velocity pressure exposure coefficient factor more quantitatively and objectively, by including geographic features, as compared to current methods. Thus, this method is expected to eliminate inaccuracies that arise when building designers calculate the velocity pressure exposure coefficient in subjective way, and to help increase the wind resistance of buildings in a more logical and cost-effective way.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.89-92
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• 2015

In this paper, we propose a method to reduce the fire suppression time. Our suggestions can secure a safe area according to the diffusion path and speed of the fire, forest fire prediction minimize casualties and property damage forests. The existing path prediction method wildfire spread predict the wildfire spread model and speed through topography, weather, fuel factor and the image information. In this case, however, occur to control a large mountain huge costs. Also Focus on the diffusion model predictions and the path identified by the problem arises that insufficient efforts to ensure the safe area. In this paper, we estimate the moving direction and speed of fire at a lower cost, and proposes an algorithm to ensure the safety zone for fire suppression. The proposed algorithm is a technique to analyze the attribute information that temperature, wind, smoke measured over time. According to our algorithm forecast wildfire moving direction and ensure the safety zone. By analyzing the moving speed and the moving direction of the simulated fire in a given environment is expected to be able to quickly reduce the damage to the forest fire fighters.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.4A
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• pp.352-360
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• 2008

Recently Task Group (TG) 4 of the Institute of Electrical and Electronics Engineers (IEEE) 802.15a has been recommended a system with ranging capability in existence of multiple Simultaneous operating piconets (SOPs) as well as low-cost, low-power. According to the ranging service, coherent and non-coherent based ranging schemes using ternary code have been adopted as a standard. However it is hard to estimate an accurate time of arrival (TOA) in case of using direct sequence based TOA estimation method because pulse repetition interval (PRI) offered by TG is more limited than the maximum excess delay (MED) of channel. To mitigate inter pulse interference (IPI) problem, this paper proposes a non-coherent TOA estimation scheme using non-periodic transmission (NPT) pattern. The proposed receiver is based on a non-coherent energy detection considering with motivation of low rate wireless personal area network (LR-WPAN). TOA information is estimated via proper comparison with a prescribed threshold after the sliding correlation and search back window (SBW) process for reducing TOA error. To verify the performance of proposed ranging scheme, two distinct channel models approved by IEEE 802.15.4a TG are considered. According to the simulation results, we could conclude that the proposed scheme have performed better performance than the conventional method on the existence of multiple SOPs.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.49 no.3
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• pp.38-46
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• 2012

Atrial fibrillation is needed to be detected at paroxysmal stage and to be treated. But, paroxysmal atrial fibrillation ECG is hardly obtained with 12-lead electrocardiographs but Holter systems. Presently, the averaged beat subtraction(ABS) method is solely used to estimate atrial fibrillatory waves even with somewhat large residual error. As an alternative, in this study, we suggested an ESAF(event-synchronous adaptive filter) based algorithm, in which the AF ECG was treated as a primary input and event-synchronous impulse train(ESIT) as a reference. And, ESIT was generated so to be synchronized with the ventricular activity by detecting QRS complex. We tested proposed algorithm with simulated AF ECGs and real AF ECGs. As results, even with low computational cost, this ESAF based algorithm showed better performance than the ABS method and comparable performance to algorithm based on PCA(principal component analysis) or SVD(singular value decomposition). We also proposed an expanded version of ESAF for some AF ECGs with multi-morphologic ventricular activities and this also showed reasonable performance. Ultimately, with Holter systems including our proposed algorithm, atrial activity signal can be precisely estimated in real-time so that it will be possible to calculate atrial fibrillatory rate and to evaluate the effect of anti-arrhythmic drugs.