• The Mathematical Education
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• v.60 no.4
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• pp.509-527
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• 2021

We investigated whether and how pre-service teachers took the realistic contexts seriously in the course of solving word problems; additionally, we investigated how pre-service teachers evaluated students' realistic and non-realistic answers to word problems. Many pre-service teachers, similar to students, solved some of the realistic problems unrealistically without taking the realistic contexts seriously. Besides, they evaluated students' non-realistic answers higher than the realistic answers. Whether the pre-service teachers could solve problems realistically or not, they did not appreciate students' realistic considerations for the reasons that those were not fitted to the intentions of the word problems, or those were evidence of the flaws of the problem. Furthermore, the analysis of premises implied in the pre-service teachers' evaluation comments showed the implicit didactic contracts about realistic word problem solving that they accepted and also anticipated students to follow. Our analysis of the pre-service teachers' conceptions of realistic word problems can help teacher educators design the teacher program to challenge and revise pre-service teachers' folk pedagogy.

• Journal of the Korean Wood Science and Technology
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• v.44 no.5
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• pp.664-676
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• 2016

Recently, the demand on the Hanok have been increased with social change. However, Hanok has a major problem of a rising costs caused by hand-made process. So, performance comparison between hand-made process and pre-cut process was conducted to modularize the joints in Hanok. Douglas-fir was used to manufacture the structural size dovetail joints by hand-made and pre-cut precess. The bending strengths on joints with two process were evaluated. The average ultimate load of pre-cut joints was 1.5 times higher than that of hand-made joints. F-test results in both process showed a great relationships between ultimate load and tenon's size variation. The length and thickness of tenon showed a proportional relationship with the ultimate load, but the tenon width showed inverse proportion with the ultimate load. This results may be used as basic data for the joint modularization of Hanok.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.2
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• pp.183-192
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• 2015

Response surface methodology (RSM) based on a Box-Behnken Design (BBD) was applied to optimize the thermal-alkaline pre-treatment operating conditions for anaerobic digestion of flotation scum in food waste leachate. Three independent variables such as thermal temperature, NaOH concentration and reaction time were evaluated. The maximum methane production of 369.2 mL $CH_4/g$ VS was estimated under the optimum conditions at $62.0^{\circ}C$, 10.1% NaOH and 35.4 min reaction time. A confirmation test of the predicted optimum conditions verified the validity of the BBD with RSM. The analysis of variance indicated that methane production was more sensitive to both NaOH concentration and thermal temperature than reaction time. Thermal-alkaline pretreatment enhanced the improvement of 40% in methane production compared to the control experiment due to the effective hydrolysis and/or solubilization of organic matters. The fractions with molecular weight cut-off of scum in food waste leachate were conducted before and after pre-treatment to estimate the behaviors of organic matters. The experiment results found that thermal-alkaline pre-treatment could reduce the organic matters more than 10kD with increase the organic matters less than 1kD.

• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.179-185
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• 2012

This paper proposes a design of RSIDS(RST and SVM based Intrusion Detection System) using RST(Rough Set Theory) and SVM(Support Vector Machine) algorithm. The RSIDS consists of PrePro(PreProcessing) module, RRG(RST based Rule Generation) module, and SAD(SVM based Attack Detection) module. The PrePro module changes the collected information to the data format of RSIDS. The RRG module analyzes attack data, generates the rules of attacks, extracts attack information from the massive data by using these rules, and transfers the extracted attack information to the SAD module. The SAD module detects the attacks by using it, which the SAD module notifies to a manager. Therefore, compared to the existing SVM, the RSIDS improved average ADR(Attack Detection Ratio) from 77.71% to 85.28%, and reduced average FPR(False Positive ratio) from 13.25% to 9.87%. Thus, the RSIDS is estimated to have been improved, compared to the existing SVM.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.1000-1003
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• 2014

As smart phones have became popular in recent years, use rate of smart phones application of mobile subscribers is now gradually increasing. Smart phones have a considerable effect on real life of users. Especially, mobile payment service using smart phones is outstanding in convenience because of its simple way to check out online. Therefore, in this paper, the database was designed for inquiring and making pre-order for take-out products based on connivence. This paper offers pre-order design to have order information standardized, menus which store owners can register and manage, and statistical data based on sales. It can be cost and time-efficient by using integrated pre-order system across all franchises. If this take-out pre-order system becomes more widely available, it will increase profit for both users and franchises due to cost and time efficiency.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.461-464
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• 2014

As smart phones have became popular in recent years, use rate of smart phones application of mobile subscribers is now gradually increasing. Smart phones have a considerable effect on real life of users. Especially, mobile payment service using smart phones is outstanding in convenience because of its simple way to check out online. Therefore, in this paper, the database was designed for inquiring and making pre-order for take-out products based on connivence. This paper offers pre-order design to have order information standardized, menus which store owners can register and manage, and statistical data based on sales. It can be cost and time-efficient by using integrated pre-order system across all franchises. If this take-out pre-order system becomes more widely available, it will increase profit for both users and franchises due to cost and time efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.10
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• pp.1537-1544
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• 2022

When designing chip, it considers design specification, timing problem, and clock synchronization on place & route (P&R) process. P&R process is complicated because of considering various factors. Chip uses clock tree synthesis (CTS) to reduce clock path delay. The purpose of this study is to examine shallow-CTS algorithm for checking clock tree synthesizable. Using open source Parser-Verilog, register transfer level (RTL) synthesizable Verilog file is parsed and it uses Pre-CTS and Post-CTS process that is included shallow-CTS. Based on longest clock path in the Pre-CTS and Post-CTS stages, the standard deviation before and after buffer insertion is compared and analyzed for the accuracy of CTS. In this paper, It is expected that the cost and time problem could be reduced by providing a pre-clock tree synthesis verification method at the RTL level without confirming the CTS result using the time-consuming licensed EDA tool.

• Tunnel and Underground Space
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• v.33 no.4
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• pp.255-264
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• 2023

As the demand for urban underground space increases recently, urban tunnel planning is actively progressing. In the urban area, a underground station is planned in consideration of the living environment of residents, and 2-arch tunnel is applied for the stability of existing structures and reduction of environmental damage. However, since the depth of weak rock mass is deeply distributed in the urban area due to severe weathering, careful planning is required to secure tunnel stability. In addition, if TBM mechanical excavation is applied as the main tunnel excavation method considering the composite ground in urban area, the construction connectivity with the 2-arch tunnel of the NATM concept may be deteriorated. In this study, the design case of applying TBM pre-excavation type 2-arch tunnel for the first time in Korea was mainly described. The main considerations for the segment design of TBM pre-excavation type 2-arch tunnel were explained for side tunnels. Also, a stability analysis was conducted to verify the effectiveness and adequacy of the TBM pre-excavation type 2-arch tunnel.

• The Korea Genome Conference
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• 2002.08a
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• pp.46.1-46.1
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• 2002

• Journal of the Korean Society for Precision Engineering
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• v.10 no.4
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• pp.236-247
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• 1993

An davanced method for the automatic generation of parametric models in computer- aided design systems is required for most of two-dimensional model which is represented as a set of geometric elements, and constraining scheme formulas. The development system uses geometric constraints and support of topology parameters from feature recognition and grouping the design entities into optimal ones from pre-designed drawings. The aim of this paper is to present guidelines for the application and development of parametric design modules for the standard parts in mechanical system, the basic constitutional part of mold base, and other 2D features.