• Journal of Korean Society of Forest Science
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• v.99 no.6
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• pp.891-899
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• 2010

The purpose of this study is to estimate economic value of forest landscape function using conditional logit model, applied by Choice Experiment. For the study, we have chosen attributes and levels of forest landscape. In specific, topographical forest type, forest type, forest density, recreational factor (side trip, accessibility of valley) and WTP were included in attributes. Based on factors, we have made 48 choice sets with Balanced and Orthogonal form using SAS 9.1. The efficiency of questionnaire was 6.02 (D-Error: 0.1) and choice set and socio-economic variable were selected. In order to reduce cognitive load of respondent, 96 choice sets were divided into 4 types in questionnaire so that respondent could respond to 12 choice sets respectively. Population was citizens from 7 metropolitan cities including Seoul, and the interview survey was conducted to find out average annual WTP per household for the total 280 interviewees. As a result, In the Non-ASC model, Mcfadden' ${\rho}$ had 0.21, and Log Likelihood: -2,631. Average annual WTP per household for forest landscape was 266,723 Won(Korean currency).

• International Commerce and Information Review
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• v.7 no.3
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• pp.269-286
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• 2005

The exchange rate volatility has been increased since the time when the floating exchange rate system was introduced in Korea. As a result, the increase of the exchange rate volatility raised the risk in international trades in Korea. The purpose of this study in to study the feature of exchange rate volatility and the main sources of its increase and to confirm whether the exchange rate volatility influence export volume and price of Korea. In the first place, I measured exchange rate volatility with two methods. The one is descriptive statistic method such as the width of daily exchange rate fluctuation and the rate of exchange rate devaluation. The other is the time varying conditional variance of exchange rate. Then, I studied the sources of exchange rate volatility. In the second place, I defined the exchange rate volatility as the time varying conditional variance and estimated it by using elastic a approach model which shows exchange rate is affected by itself and its conditional variance, I estimated its effects on export volumes and prices of electric home appliances, information & communication equal and semi-conductor. The result of this study is as follows. With presumed result EU and Korea because is not the goods which is to substantial competition relationship, The effect where the relative value change of presumed result expression anger and the dollar of import and export function goes mad to the import and export of Korea the income compared to is to export and it is appearing a lot. The EU goods is sold more expensively the Korean goods than from about length being caused by American market of the dollar and the balance of trade of Korea is visible like being visible the improvement of single breadth. Because the relationship of competition is weak but substantially there is to a short term and expression - the effect where the dollar rate fluctuation is big in Korean trade there is a possibility of saying that widely known it is not.

• Smart Structures and Systems
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• v.20 no.1
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• pp.11-22
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• 2017

The long-term effect of ambient temperature on bridge strain is an important and challenging problem. To investigate this issue, one year data of strain and ambient temperature of a long-span cable-stayed bridge is studied in this paper. The measured strain-time history is decomposed into two parts to obtain the strains due to vehicle load and temperature alone. A linear regression model between the temperature and the strain due to temperature is established. It is shown that for every $1^{\circ}C$ increase in temperature, the stress is increased by 0.148 MPa. Furthmore, the extreme value distributions of the strains due to vehicle load, temperature and the combination effect of them during the remaining service period are estimated by the average conditional exceedance rate approach. This approach avoids the problem of declustering of data to ensure independence. The estimated results demonstrate that the 95% quantile of the extreme strain distribution due to temperature is up to $1.488{\times}10^{-4}$ which is 2.38 times larger than that due to vehicle load. The study also indicates that the estimated extreme strain can reflect the long-term effect of temperature on bridge strain state, which has reference significance for the reliability estimation and safety assessment.

• The Korean Journal of Applied Statistics
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• v.24 no.1
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• pp.61-69
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• 2011

In GARCH context, the conditional variance (or volatility) is of a quadratic function of the observation process. Examine standard ARCH/GARCH and their variant models in terms of quadratic formulations and it is interesting to note that most models in GARCH context have contained neither the first order term nor the interaction term. In this paper, we consider three models possessing the first order and/or interaction terms in the formulation of conditional variances, viz., quadratic GARCH, absolute value GARCH and bilinear GARCH processes. These models are investigated with a view to model comparisons and applications to financial time series in Korea

• Journal of applied mathematics & informatics
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• v.26 no.3_4
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• pp.661-672
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• 2008

In this paper an algorithm, based on extracting a certain target of an image, is proposed that is capable of performing bilevel thresholding of image with multimodal distribution. Each pixel in the image has a membership value which is used to denote the characteristic relationship between the pixel and its belonging region (i.e. the object or background). Using the membership values of image set, a new measurement, which simultaneously measures the measure of fuzziness and the conditional entropy of the image, is calculated. Then, thresholds are found by optimally minimizing calculated measurement. In addition, a fuzzy range is defined to improve the threshold values. The experimental results demonstrate that the proposed approach can select the thresholds automatically and effectively extract the meaningful target from the input image. The resulting image can preserve the object region we target very well.

• International Journal of Computer Science & Network Security
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• v.21 no.11
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• pp.105-110
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• 2021

Contact between Vehicle-to-vehicle and vehicle-to-infrastructural is becoming increasingly popular in recent years due to their crucial role in the field of intelligent transportation. Vehicular Ad-hoc networks (VANETs) security and privacy are of the highest value since a transparent wireless communication tool allows an intruder to intercept, tamper, reply and erase messages in plain text. The security of a VANET based intelligent transport system may therefore be compromised. There is a strong likelihood. Securing and maintaining message exchange in VANETs is currently the focal point of several security testing teams, as it is reflected in the number of authentication schemes. However, these systems have not fulfilled all aspects of security and privacy criteria. This study is an attempt to provide a detailed history of VANETs and their components; different kinds of attacks and all protection and privacy criteria for VANETs. This paper contributed to the existing literature by systematically analyzes and compares existing authentication and confidentiality systems based on all security needs, the cost of information and communication as well as the level of resistance to different types of attacks. This paper may be used as a guide and reference for any new VANET protection and privacy technologies in the design and development.

• Asia-Pacific Journal of Business
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• v.12 no.4
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• pp.63-86
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• 2021

Purpose - The purpose of this study is to explore the impact of the application of accounting conservatism on the investment efficiency of listed companies in China under the background of the current rising environmental uncertainty. Design/methodology/approach - This study collected 14,934 observations of A-share listed companies in Shanghai and Shenzhen from 2013 to 2020, and analyzed the data by means of moderating effect test and multiple regression analysis. Findings - The results show that environmental uncertainty deteriorates the company's investment efficiency. The higher the level of environmental uncertainty, the more prone to over-investment and under-investment. Accounting conservatism plays moderating role between environmental uncertainty and investment efficiency. Among them, the moderating effect of conditional conservatism is to alleviate under-investment of the company under high financing constraints and the over-investment, while it intensifies the under-investment under low financing constraints. The moderating effect of unconditional conservatism is to alleviate the under-investment. Research implications or Originality - This study finds out the internal mechanism of accounting conservatism affecting investment efficiency, which not only helps to understand about the value of accounting conservatism standards, but also helps to improve the investment efficiency of listed companies.

• Human Ecology Research
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• v.52 no.3
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• pp.243-253
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• 2014

This qualitative case study examined the experience of middle-aged homemakers with buying and wearing clothes. Clothing benefits and clothing purchase types were observed in the homemakers' daily clothing-related behavior. This study aims to understand clothing consumption values in light of clothing benefits and to determine purchasing methods, purchasing mental states, and personal characteristics according to the clothing purchase types of middle-aged homemakers. The participants of this study were four full-time homemakers and four homemakers with a job outside the home, all in middle age. This study was conducted through in-depth interviews based on an unstructured questionnaire, and the data were collected from January 2010 to October 2010. The results were as follows: first, the clothing benefits were identified as a social stereotype, aesthetic taste, economy, wearing situation, and age perception. The most important clothing consumption values to the middle-aged homemakers based on the observed clothing benefits were, in order: social value, emotional value, epistemic value, functional value, and conditional value. Second, the type of clothing purchase was observed to be planned buying, followed by impulse buying, and compensatory buying. Even when a homemaker planned to shop regularly, when they were exposed to an attractive retailer promotion, they seized on the opportunity on impulse or made a compensatory purchase to divert oneself. Even though homemakers prefer primarily impulse buying, when they went shopping for clothing with their mother-in-law or husband, they made planned purchase also.

• Fire Science and Engineering
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• v.18 no.4
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• pp.64-71
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• 2004

This paper describes the result of the pump room fire analysis of the nuclear power plant using CFAST fire modeling code developed by NIST. The sensitivity studies are performed over the input parameters of CFAST: the constrained or unconstrained fire, Lower Oxygen Limit (LOL), Radiative Fraction (RF), and the opening ratio of the fire doors. According to the results, a pump room fire is the ventilation-controlled fire, so it is adequate that the value of LOL is 10% which is also the default value. It is anlayzed that the Radiative Fraction does not affect the temperature of the upper gas layer. It is appeared that the integrity of the cable located at the upper layer is maintained except for the safety pump at the fire area and the Conditional Core Damage Probability (CCDP) is 9.25E-07. It seems that CCDP result is more realistic and less uncertain than that of Fire Hazard Analysis (FHA).

• Korean Journal of Community Nutrition
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• v.27 no.4
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• pp.309-320
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• 2022

Objectives: This study aimed to analyze the consumption values of fast foods among American consumers and compare the consumption values according to the levels of health consciousness. Methods: An online survey using a self-administered questionnaire was conducted on 351 American consumers. Based on the median health consciousness score (3.83 out of 5 points), the subjects were classified into the low health-conscious group (Low group) and the high health-conscious group (High group). Factor analysis was used to extract factors for the five consumption values (functional, social, emotional, conditional, and epistemic values). The differences in the consumption values between the two groups were analyzed. Results: A total of 14 factors were extracted for the five consumption values and 9 factors among them (convenience, healthiness, and taste in functional values; health-conscious people, young, busy, obese people, low class, and budget restricted people in social values; guilt in emotional values; accidental situations in conditional values) showed significant differences between the two groups. The Low group had a higher perception of the factor of healthiness (P < 0.001) than the High group. The High group had a relatively higher perception of the factors of convenience (P < 0.001), taste (P < 0.001), and guilt (P < 0.001). In addition, the High group perceived the social values of fast foods more negatively. The High group consumed fast foods less frequently than the Low group and perceived their health status and healthiness of eating habits more positively. Conclusions: The results reveal that the health consciousness level significantly influences consumption value perceptions about fast foods in American consumers. Policymakers and marketers can develop effective strategies based on the results of this study.