• Journal of Conservation Science
• /
• v.34 no.5
• /
• pp.379-385
• /
• 2018

This study examined the condition of degraded plastic artifacts and conducted materials assessments for conservation treatment. The properties and bond characteristics of five types of adhesives(EVA, PVAc, Cyanoacrylate) were evaluated to select the adhesive most suitable for conservation treatment. The degradation of plastic artifacts caused cracks, peelings, and surface warping. According to the FT-IR analysis, the synthetic resin used in the artifact was estimated to EVA type. The properties of the adhesives were evaluated through acidity, and hardness measurements. The results showed that acidity varies with the type of adhesive, and that the hardness of PVAc was higher than those of EVA. On comparing the bond characteristics of the samples after artificial degradation, it was found that PVAc and Cyanoacrylate increased the chromaticity and hardness of the samples, while EVA was the most stable with relatively little change. Thus, EVA was confirmed to be the most suitable materials for conservation treatment of degraded plastic artifacts. In this study, as the experiment of treatment materials based on actual artifact, it is expected that it could be used a basis research for conservation treatment of plastic artifacts.

• Journal of the Economic Geographical Society of Korea
• /
• v.23 no.1
• /
• pp.56-70
• /
• 2020

This study identifies the impact of social network service (SNS) on the spatial characteristics of retail stores locations in the hyper-connected society, which have been closely related to the everyday lives of urban residents. In particular, we focus on the changes in the spatial distribution of restaurants since the information retrieval process was added to the decision-making process of a consumer's restaurant selection. Empirically, we analyze restaurants in Seoul, Korea since the smart-phone was introduced. By applying the kernel density estimation and Moran's I index, we examine the changes in the spatial distribution pattern of restaurants during the last ten years for running, newly-open and closed restaurants as well as SNS popular ones. Finally, we develop a spatial regression model to identify geographic features affecting their locations. As the results, we identified geographical variables and online factors that influence the location of restaurants. The results of this study could provide important groundwork for food and beverage location planning and policy formulation.

• Journal of the Korean GEO-environmental Society
• /
• v.9 no.3
• /
• pp.17-28
• /
• 2008

In this study, the residual strength prediction models were proposed by measuring various residual strength according to pit characteristics for metallic water pipes such as cast iron pipe (CIP), ductile iron pipe (DIP), and steel pipe (SP). The exponential prediction model was better fitted to measured residual tensile strength for CIP. In case of DIP and SP, the prediction model using loss of strength was more exactly predicted compared with other model types. The fracture toughness were averagely $40.46kgf/mm^2{\sqrt{mm}}$ for CIP, $85.27kgf/mm^2{\sqrt{mm}}$ for DIP, and $92.27kgf/mm^2{\sqrt{mm}}$ for SP, the determination coefficient ($R^2$) of between measured residual tensile strength and predicted values for residual strength prediction models using fracture toughness was estimated from 0.44 to 0.86. Especially, the proposed residual tensile strength prediction models were applied for the verification and reliability to CIPs and DIPs at 14 sites. The determination coefficient ($R^2$) between measured residual tensile strength and predicted values was estimated from 0.76 to 0.78. Therefore it was thought that the proposed residual tensile strength models could help to support resonable and economical decision of rehabilitation/replacement.

• Journal of Digital Convergence
• /
• v.13 no.9
• /
• pp.57-75
• /
• 2015

The study introduces the case of initial adoption and convergence of accounting system under the K-IFRS by the quasi-government entity, the National Research Foundation of Korea(NRF). Followings are the methodology used in the study. (1) The study provides several accounting issues, their impact on the financial information of the NRF and implications about NRF's financial information in the course of convergence of accounting system under the K-IFRS. (2) As examples of accounting issues, the NRF reflected several accounting difference such as revaluation of fixed assets, economic useful life, depreciation method, reclassification of investment, representation of transfer revenue from the government, the timing of revenue recognition, and employ benefits, etc. As results of adjustments under the K-IFRS, the NRF decreased 1,109 billion of total assets and 1,064 billion of total liabilities. Also, increase in operating expenses results a slight decrease in net income, which may have an impact on future management evaluation of the NRF. A successful case of K-IFRS adoption by the NRF which brings deep insight on adoption and convergence of new accounting system to other quasi-government entity.

• Journal of Korean Society of Forest Science
• /
• v.90 no.6
• /
• pp.725-733
• /
• 2001

In this study, the relationship between growth factors for Pinus densiflora stands in Anmyun-Island was analyzed and dynamic growth model was prepared. A total of 96 sample plots was investigated in which dbh and height of individual trees were measured. From these plot data, quadratic mean dbh, mean height, dominant tree height, stem number per ha, basal area per ha and volume per ha were estimated. Several regression equations between growth factors were derived using NLIN and REG procedure of SAS. And dynamic growth model, in which the equations were interactively linked, was prepared for the prediction of stand growth and yield under different management regime. The predictions of dynamic growth model were found to be coincided with general growth principles. The dynamic growth model was considered as adequate for predicting growth and yield of Pinus densiflora stand in Anmyun-Island. In practice, the dynamic growth model can be applied for predicting the growth and development of stand for various forest treatments and for decision-making in forest management.

• Research in Plant Disease
• /
• v.26 no.4
• /
• pp.229-238
• /
• 2020

Field validation of PBcast, an infection risk model for Phytophthora blight of pepper, was conducted through a designed field experiment in 2012 and 2013. Conduciveness of weather conditions at 26 locations in Korea in 2014-2017 was also evaluated using PBcast. The PBcast estimated daily infection risk (IR) of Phytophthora capsici based on weather and soil texture data. In the designed filed experiment, four treatments including routine sprays at 7-day intervals (RTN7), forecast-based sprays when IR reached 200 (IR200) and 224 (IR224), and no spray (CTRL) were compared in terms of disease incidence and number of sprays recommended for disease control. In 2012, IR had reached over 200 twice, but never reached 224. In 2013, IR had reached over 200 three times and once higher than 224. The RTN7 plots were sprayed 17 and 18 times in 2012 and 2013, respectively. Weather conditions throughout the country were generally conducive for Phytophthora blight and 3-4 times of fungicide sprays would have been reduced if the PBcast forecast information was adopted in the decision-making for fungicide sprays. In conclusion, the PBcast forecast would be useful to reduce fungicide applications without losing the disease control efficacy to protect pepper crop from Phytophthora blight.

• Knowledge Management Research
• /
• v.22 no.2
• /
• pp.247-268
• /
• 2021

Investors mainly use PER and PBR among financial ratios for valuation and investment decision-making. I conduct an analysis of two basic financial ratios from a statistical perspective. Financial ratios contain key accounting numbers which reflect firm fundamentals and are useful for valuation or risk analysis such as enterprise credit evaluation and default prediction. The distribution of financial data tends to be extremely heavy-tailed, and PER and PBR show exceedingly high level of kurtosis and their extreme cases often contain significant information on financial risk. In this respect, Extreme Value Theory is required to fit its right tail more precisely. I introduce not only GPD but exGPD. GPD is conventionally preferred model in Extreme Value Theory and exGPD is log-transformed distribution of GPD. exGPD has recently proposed as an alternative of GPD(Lee and Kim, 2019). First, I conduct a simulation for comparing performances of the two distributions using the goodness of fit measures and the estimation of 90-99% percentiles. I also conduct an empirical analysis of Information Technology firms in Korea. Finally, exGPD shows better performance especially for PBR, suggesting that exGPD could be an alternative for GPD for the analysis of financial ratios.

• Journal of Korea Water Resources Association
• /
• v.55 no.2
• /
• pp.159-170
• /
• 2022

As the severity of water-related disasters increases in urban watersheds due to climate change, reducing flood damage in urban watersheds is one of the important issues. This study focuses on prioritizing the optimal site for permeable pavement to maximize the efficiency of reducing flood damage in urban watersheds in the future climate environment using multi-criteria decision making techniques. The Mokgamcheon watershed which is considerably urbanized than in the past was selected for the study area and its 27 sub-watersheds were considered as candidate sites. Six General Circulation Model (GCM) of Coupled Model Intercomparison Project 6(CMIP6) according to two Shared Socioeconomic Pathway (SSP) scenarios were used to estimate future monthly precipitation for the study area. The Driving force-Pressure-State-Impact-Response (DPSIR) framework was used to select the water quantity evaluation criteria for prioritizing permeable pavement, and the study area was modeled using ArcGIS and Storm Water Management Model (SWMM). For the values corresponding to the evaluation criteria based on the DPSIR framework, data from national statistics and long-term runoff simulation value of SWMM according to future monthly precipitation were used. Finally, the priority for permeable pavement was determined using the Fuzzy TOPSIS and Minimax regret method. The high priorities were concentrated in the downstream sub-watersheds where urbanization was more progressed and densely populated than the upstream watersheds.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.26 no.5D
• /
• pp.783-796
• /
• 2006

Rut-resistance pavement is adopted to prevent pavement from plastic deformation since 1998. The objective of this paper is to investigate performance and economic efficiency between rut-resistance pavement and conventional hot-mix asphalt(HMA) on national highway. The pavement deterioration models incorporated in HDM-4 have been calibrated and adapted to local road conditions based on observed pavement rut-depth data. Based on calibration result of HDM-4, the economic evaluation including road agency cost and user cost is performed for 34 road pavement sections. Furthermore, we presented optimal timing for maintenance and performance levels subject to different budget. We found that rut-resistance pavement is performing better than conventional hot-mix asphalt in most road sections. Furthermore, we confirmed that the application of HDM-4 is useful for pavement project planning and evaluation. More investigation is needed to enlarge the scope of the pavement data and to explore more deeply socio-environmental cost and delay cost.

• The korean journal of orthodontics
• /
• v.35 no.1 s.108
• /
• pp.60-68
• /
• 2005

The evaluation of malocclusion has to be done quantitatively and qualitatively. This will be lead toward an analysis of malocclusion severity as well as treatment difficulty. The method of proper evaluation of malocclusion severity and treatment difficulty is necessary to assess treatment effect and efficiency for the orthodontists and to establish fundamentals for planning and executing the health-related policies in private and public institutions. The purposes of this study as the first part of the objective and quantitative analysis of malocclusion were 1) to measure treatment difficulty based on the opinions of several orthodontists. and 2) to investigate the relationships between objective malocclusion severity and subjective treatment difficulty 100 pairs of dental casts that had various types and severity of malocclusion were selected from the orthodontic departments of Kyurghee University and Samsung Medical Center The objective malocclusion severity was measured with the PAR (Peer Assessment Rating) index and the subjective treatment difficulty was evaluated by 8 experienced orthodontists. The relationships between objective malocclusion severity and subjective treatment difficulty were statistically evaluated. There were significant relationships between objective malocclusion severity and subjective treatment difficulty especially in the measurements of the upper anterior alignment, the buccal occlusion. the overjet, the overbite and the midline discrepancy en the malocclusion components. The results of this study can provide the background knowledge to develop a new occlusal index. which contains both the malocclusion severity and treatment difficulty for Korean orthodontists.