• Economic and Environmental Geology
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• v.40 no.3 s.184
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• pp.295-306
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• 2007

In this study, we predicted areas vulnerable to ground subsidence near abandoned underground coal mine at Sam-cheok City in Korea using a probability (frequency ratio) model with Geographic Information System (GIS). To extract the factors related to ground subsidence, a spatial database was constructed from a topographical map, geo-logical map, mining tunnel map, land characteristic map, and borehole data on the study area including subsidence sites surveyed in 2000. Eight major factors were extracted from the spatial analysis and the probability analysis of the surveyed ground subsidence sites. We have calculated the decision coefficient ($R^2$) to find out the relationship between eight factors and the occurrence of ground subsidence. The frequency ratio model was applied to deter-mine each factor's relative rating, then the ratings were overlaid for ground subsidence hazard mapping. The ground subsidence hazard map was then verified and compared with the surveyed ground subsidence sites. The results of verification showed high accuracy of 96.05% between the predicted hazard map and the actual ground subsidence sites. Therefore, the quantitative analysis of ground subsidence near abandoned underground coal mine would be possible with a frequency ratio model and a GIS.

• The KIPS Transactions:PartC
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• v.14C no.5
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• pp.417-424
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• 2007

Mesh networks using WLAN technology have been paid attention as a key wireless access technology. However, many technical issues still exist for its successful deployment. One of those issues is the routing problem that addresses the path setup through a WLAN mesh network for the data exchanges between a station and a wired network. Since the characteristics of a WLAN mesh network can be very dynamic, the use of single routing protocol would not fit for all environments whether it is reactive or proactive. Therefore, it is required to develop an adaptive routing protocol that modifies itself according to the changes in the network parameters. As a logical first step for the development, an analytical model considering all the dynamic features of a WLAN mesh network is required to evaluate the performance of a reactive and a proactive routing scheme. In this paper, we propose an analytical model that makes us scrutinize the impact of the network and station parameters on the performance of each routing protocol. Our model includes the size of a mesh network, the density of stations, mobility of stations. and the duration of network topology change. We applied our model to the AODV that is a representative reactive routing protocol and DSDV that is a representative proactive routing protocol to analyze the tradeoff between AODV and DSDV in dynamic network environments. Our model is expected to help developing an adaptive routing protocol for a WLAN mesh network.

• Korean Journal of Construction Engineering and Management
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• v.9 no.3
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• pp.164-174
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• 2008

It is crucial In decision making to select a project delivery system (PDS) adjusted accordingly to the project characteristics. Furthermore, selecting a tendering system is the kernel in the process of selecting PDS. In October 2007, the Ministry of Finance and the Economy of Korea launched two new project delivery systems, "Best Value Contract (Design-Bid-Build)" and "Bridging Contracts (Design-Build)" by revising enforcement ordinances of "Act on Contracts to Which the State is a Party" to provoke the tendering systems. In order to support the proposed purpose, this research developed a selection model for suitable tendering system, which helps a public owner select a tendering system appropriate to the project characteristics. First, the framework of the model was set throughout analyzing previous researches and interviewing relevant experts. Additionally, by analyzing the survey result from 265 experts engaged in architectural and civil engineering business, the relative weights of the selection factors and the effectiveness values of the alternatives were suggested as the quantitative evaluation references. Finally, the practical guideline was suggested to apply this model to three public projects scheduled to be delivered. The result of applying the model to three case projects showed that further researches were needed to make the selection process logical and to suggest the standard weights and effectiveness values according to project type.

• Science of Emotion and Sensibility
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• v.11 no.4
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• pp.575-588
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• 2008

This study is to inquire respective patterns of mental models caused by wrongful usages which can be experienced when a user who is used to a keypad-based mobile phone starts using a touch screen mobile phone and to find out the features of the user's logical process of correcting such wrongful usages to a new mental model. In addition, design improvement to be considered for easy generation of the mental model regarding touch screen mobile phones was reviewed in this study. We set up test subjects for the most frequently used seven high priority functions among touch screen phone functions and carried out the subject assessment together with interview surveys after the video observation experiment. Our test results show that test subjects who were used to keypad-based mobile phones tend to use operation knowledge related to the computer operational system(Window) or the web browse, navigation including Tap or Double Tap in order to correct the mental model when a wrongful usage is made. In addition, the result of comparison and analysis of the subject assessment and the video observation experiment data shows that wrongful usages of touch screen mobile phones mostly occurred in the field of 'information feedback' and 'navigation' among mobile phone components.

• Journal of The Korean Association of Information Education
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• v.19 no.1
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• pp.149-158
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• 2015

Programming education plays a very effective role in comprehensively learning problem analysis ability, logical thinking ability, procedural problem solving method, and imaginary problem solving method. Until recently, however, it is not applied to the elementary and the middle school in Korea, which is very different from the other IT centerd countries such as the U.S., etc., where coding class is actively implemented. Fortunately, Korean government recognized this reality and decided to implement programming education as a regular subject in the elementary school from 2017. In this situation, many researchers' programming education model research is urgently required for the students to learn in the elementary and the middle school. This research developed and suggested 17 sessions of programing education model connected with scratch language and sensor board, which is hardware, to be applied to the class of the 5th and 6th graders. As the result of implementing the joint class of 5th and 6th graders during the after-school class based on programming education process suggested to verify the suitability for elementary school programing education, satisfactory achievement was attained by the assessed students. The researcher plans to develop an optimum model proper for the elementary school students' intellectual capacity by more improving programming education model.

• Environmental and Resource Economics Review
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• v.23 no.2
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• pp.187-224
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• 2014

We present key issues to consider in estimating damages from price-fixing cases and then apply the procedure addressing those issues to a transportation fuel market. Among the five methods of overcharge calculation, the regression analysis incorporating the yardstick method is the best. If the price equation relates the domestic price to the foreign price and the exchange rate as in the transportation fuel market, the functional form satisfying both logical consistency and modeling flexibility is the log-log functional form. If the data under analysis is of time series in nature, then the ARDL model should be the base model for each market and the regression analysis incorporating the yardstick method combines these ARDL equations to account for inter-market correlation and arrange constant terms and collusion-period dummies across component equations appropriately so as to identify the overcharge parameter. We propose a two-step test for the benchmarked market: (a) conduct market-by-market Spearman or Kendall test for randomness of the individual market price series first and (b) then conduct across-market Friedman test for homogeneity of the market price series. Statistical significance is the minimal requirement to establish the alleged proposition in the world of uncertainty. Between the sensitivity analysis and the model selection process for the best fitting model, the latter is far more important in the economic analysis of damage in price-fixing litigation. We applied our framework to a transportation fuel market and could not reject the null hypothesis of no overcharge.

• The KIPS Transactions:PartD
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• v.8D no.3
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• pp.295-304
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• 2001

The standards of a telephone Hangul keyboard should be decided in terms of objective factors : the number of strokes and fingers’moving distance. A number of designers will agree on them, because these factors can be calculated in an objective manner. So, We developed the model which can evaluate the efficiency of inputting Hangul on a telephone keyboard in terms of two factors. As compared with other models, the major features of this model are as follows : in order to evaluate the efficiency of Hangul input on a telephone keyboard, (1) this model calculated not a typing time but the number of strokes ; (2) concurrence frequency that had been counted on KOREA-1 Corpus was used directly ; (3) a total set of 67 consonants and vowels was used ; and (4) this model could evaluate a number of keyboards that use a kind of syllabic function key-the complete key, the null key and the final consonant key and also calculate a lot of keyboards that adopt no syllabic function key. However, there are many other factors to judge the efficiency of inputting Hangul on a telephone keyboard. If we want to make more accurate estimate of a telephone Hangul keyboard, we must consider both logical data and experimental data as well.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.159-168
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• 2013

This study analyze the business efficiency of securities company based on the 2011 performance of 29 securities firms which engage in domestic investment brokerage by applying a combination model of BSC and DEA. And we evaluate business state focused on efficiency which is based on logical system of BSC as business innovation method. The analysis of result is that companies with high customer efficiency index appeared that business efficiency composite index tended to be higher and we identified that customer perspective have an important factor to calculate business efficiency composite index of korea security company. In addition, based on the results of the efficiency analysis we analyze correlation analysis between traditional financial ratio and business efficiency composite index. We confirmed that company of high business efficiency level in terms of BSC have a good record in terms of profitability. BSC-DEA combination model expect to be utilized in security industry sector as well as other industrial sectors as good business indicator to determine the business efficiency and to be used a model can be evaluated the integrated firm valuation of tangible and intangible assets.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.2
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• pp.174-190
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• 1996

Damage assessment based on in situ surveys for oil spills in marine environment is limited by fundamental difficulties as well as tremendous expenses. Except for intertidal zones, the damage is not preserved well. Also such surveys are usually confined to adult organisms. To overcome these limitations a computer model, NRDAM/CME, was developed in the case of USA (Reed et al., 1989), where an acute toxicity data base was used to assess indirect damages through food webs and loss due to recruitment as well as adult losses. In the present study damage assessment of natural biological resources for hypothetical oil spills is attempted using a computer model for hypothetical spills of Bunker C and heavy crude oil. In the model, the logical structure of NRDAM/CME was adopted, and biomass and productivity database were compiled for the Korean waters. The results showed that the damage increased in a nonlinear fashion as the spill amount increased. The magnitude of the damage depended upon the chemical properties of oil viscosity and solubility in particular, which implies that usage of oil dispersant might increase the damage by dispersing oil. The results also indicate that long term damage due to recruitment loss could be greater than short term damage.

• Journal of Gifted/Talented Education
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• v.20 no.1
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• pp.1-30
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• 2010

The purpose of this study was to develop the inspection model of cognitive ability to identify visual artistic giftedness of the elementary school children with considering the relation between visual artistic giftedness and cognitive ability based on literature and preceding research. The research method applied literature research and quantitative research. Through literature review on the relation between art education and cognitive thinking and visual artistic of giftedness, it was suggested to prescribe the validity of cognitive ability as an element for identification of visual artistic giftedness identification, and then prescribed the elements of cognitive ability, and developed the inspection model of cognitive ability by measuring specific variables. Based on the results of literature research through the quantitative research, verified significance of developed inspection instrument on cognitive ability, validity and reliability of the inspection model of cognitive ability according to visual artistic giftedness identification of the elementary school children. As a result of reviewing related literature and preceding research, it could be referred that visual thinking ability, spatial perception power and critical thinking ability coincided with a characteristic of an art field can show excellent ability in various art activities and be valid criteria of visual artistic giftedness as cognitive ability of the visual artistic gifted with potential possibilities. In conclusion, as the elements of cognitive ability for the visual artistic giftedness identification of the elementary school children, visual thinking ability, spatial perception power and critical thinking ability were verified to be valid in terms of logical and experimental. Therefore, the result of the research will be able to provide a new approach in education program development of visual artistic giftedness of the elementary school children and a various developmental possibility in identification of visual artistic giftedness.