• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.10a
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• pp.30-35
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• 2003

Recently, with the rapid growth of information technology, many studies have been performed to implement web-based manufacturing system. Such technologies are expected to meet the need of many manufacturing industries those want to adopt E-manufacturing system for the construction of globalization, agility, digitalization to cope with the rapid changing market requirements. In this research, areal-time web-based machine tool and machining process monitoring system is developed as a first step fur implementing I-manufacturing system. In this system, main spindle motor current and feed current are measured using hall sensors. And the relationship between the cutting force and the spindle motor RMS current at various spindle rotational speed is obtained. Also, a rule-based expert system is developed in order to monitor the machining process effectively. Finally, developed system is applied to real machining process to verify the effectiveness.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.8
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• pp.5355-5362
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• 2014

This study reviewed the planning characteristics of dormitories for secondary schools in the Japanese Colonial Era by analyzing the architectural drawings collected by the National Archives of Korea. The dormitory was one of the essential facilities in secondary schools but there have been few studies in this area. The analysis items were the site plan and the planning characteristics of student bedrooms, dining hall, and supervisor's area, which were the main elements of the dormitory. The results of this study were summarized as follows. 1) Generally, the dormitory area was placed in the rear of buildings for teaching with a close connection. 2) The student bedroom wings were laid out in parallel to the south as a rule making the typical site plan pattern for a dormitory, whereas the other parts of dormitory, such as the dining hall and supervisor's area were placed in the site conditions. 3) Generally, the unit plans of bedrooms for Korean schools were the ondol type and were small in size, whereas those for Japanese were the tatami type and large in size with separate study and sleeping areas. 4) The dining hall annex was made up of a dining hall and kitchen-bathroom area in general. For Japanese schools, the school store area was added to these areas. The typical shapes of dining hall plans were narrow and long with an adjacent corridor, so the overall plan of the dining hall annex was like that of a single-corridor type block plan. 5) The supervisor's area was a smaller part of the dormitory but it was considered to be a symbolic part of the whole dormitory in site planning and design.

• Korean Journal of Heritage: History & Science
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• v.47 no.3
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• pp.4-23
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• 2014

Seokjojeon Hall is the Neoclassic style building situated in Deoksugung Palace, which was proposed by John McLeavy Brown who was a chief commissioner of the Daehan Empire and designed by John Reginald Hardings in 1897. Construction of the Seokjojeon Hall began in 1900 and completed in 1910 at the total cost of one million won. Decorating and furnishing of the interior was designed by Lovell and all the furniture of Seokjojeon Hall had been purchased from Maple&Co. The Maple&Co was the supplier of luxury furnitures and decorating items for luxurious residentials, hotels, embassies and the palaces and its headquarter was located in London. Ready-made furnitures were purchased as shown in the Maple's catalog. The designs and styles of the west were applied to Seokjojeon Hall. That is one of the aspects showing Daehan Imperial underwent a period of Westernization.

• Korean Journal of Heritage: History & Science
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• v.47 no.1
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• pp.18-31
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• 2014

This study aims at identifying of characteristics and types of the pigments used for Dancheong(surface decorative and protective pigments) of Yaksajeon Hall in Gwallyoungsa Temple using a Micro-XRF, XRD, SEM-EDS and thereafter, comparing it with the pigments of the wall painting in the same building and with Dancheong pigments of Daeungjeon Hall. The results can be briefly summarized as two points. First, different types of pigments for red, green and white colours had been applied based on different parts of the building and more than two different pigments had been mixed to produce various colours in so me parts. Second, scientific analysis has confirmed that raw minerals for each colour groups are: Cinnabar, minium and Hematite for red; white clay and oyster shell white($Al_2O_3{\cdot}SiO_2{\cdot}4H_2O$) for white; Atacamite and Celadonite for green; carbon(C) for black; Yellow Ocher for yellow; and Lazulite for blue. Comparative analysis of such result with that of the wall paintings and of Dancheong of Daeungjeon Hall has revealed that similar minerals had been used in overall except that several different pigments had been added or removed for making green, white and yellow colour groups in some parts. In conclusion, the result has displayed that painters had used different ways of producing pigments by a type of painting or a building within the same period or for the buildings in the same buddhist temple compound.

• School Mathematics
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• v.17 no.3
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• pp.423-446
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• 2015

This study aims to look into the characteristics of argumentation in the task context of 'Monty Hall problem' at a high school probability class. As a result of an analysis of classroom discourses on the argumentation between teachers and second-year students in one upper level class in high school using Toulmin's argument pattern, it was found that it would be important to create a task context and a safe classroom culture in which the students could ask questions and refute them in order to make it an argument-centered discourse community. In addition, through the argumentation of solving complex problems together, the students could be further engaged in the class, and the actual empirical context enriched the understanding of concepts. However, reasoning in argumentation was mostly not a statistical one, but a mathematical one centered around probability problem-solving. Through these results of the study, it was noted that the teachers should help the students actively participate in argumentation through the task context and question, and an understanding of a statistical reasoning of interpreting the context would be necessary in order to induce their thinking and reasoning about probability and statistics.

• Korean Journal of Heritage: History & Science
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• v.47 no.1
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• pp.152-163
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• 2014

In this study, Gwanghanru Pavilion (Namwon-si, Cheonbuk Province) was dated by tree rings of pines (Pinus densiflora Sieb. et Zucc., 'sonamu' in Korean). The present Gwanghanru Pavilion is composed of three parts: main, wing and entrance parts. The main part is known to have been built in 1626 and the entrance hall in 1879, but the date of construction of the wing part is still unknown. We dated a total of 55 wood samples which were replaced during the repair process in 2001~2002. Tree-ring dates indicated that both main and wing parts were built in 1626. Tree rings also revealed that the entrance hall was constructed in 1880~1881, and both main and wing parts were heavily repaired together while appending the entrance hall. In conclusion, dendrochronology, i.e., tree-ring dating, was a useful and accurate method to identify the critical dates-such as the dates of original construction, reconstruction, repairs and extensions-for the history of Korean traditional buildings.

• Proceedings of the Korean Statistical Society Conference
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• 2002.05a
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• pp.1-5
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• 2002

We consider the problem of optimal bandwidth choice for nonparametric classification, based on kernel density estimators, where the problem of interest is distinguishing between two univariate distributions. When the densities intersect at a single point, optimal bandwidth choice depends on curvatures of the densities at that point. The problem of empirical bandwidth selection and classifying data in the tails of a distribution are also addressed.

• Journal of Electrical Engineering and Technology
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• v.12 no.1
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• pp.466-471
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• 2017

Pantograph must be correctly attached to catenary to continuously supply stable power to railway vehicle, and the device used here is Auxiliary Air Compressor (ACM). The existing ACM used the DC motor that included commutator and brush. Since maintenance and repair by mechanical friction are essential for the DC motor, BLDC motor studies have been conducted to improve this. A three-phase BLDC motor does $120^{\circ}$ two-phase commutation through hall sensors in general. However, since hall sensor is vulnerable to heat and can run only when all three sensors work normally, sensorless control method has been studied to solve this. Using back EMF Zero Crossing Point (ZCP) detection method, this paper will introduce a stable switching sensing method that has a non-commutation area in a low speed zone.

• The Korean Journal of Quaternary Research
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• v.17 no.2
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• pp.139-144
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• 2003

The purpose of this study is to identify the species and to date the woods used in the Keunjung-jeon Hall, main building of the Kyungbok palace in Seoul. Samples (144) were divided into two parts, pillars (52) and other wood materials (92). Only two species were identified. They were Abies holophylla Max. and Pinus densiflora Sieb. et Zucc.Eleven among 20 Pyungju (outer pillars) were Abies holophylla, and 9 were Pinus densiflora. Seven among 12 Naejinkoju (inner pillars) were Abies holophylla, and 5 were Pinus densiflora. Three among 4 Gwikoju (inner corner pillars) were Abies holophylla, and one was Pinus densiflora. In the other wood materials, only 2 of 92 were Abies holophylla, and the others were Pinus densiflora. Tree-ring dating proved that this building was reconstructed during late 1860s. It also revealed that the old woods cut in the 17th century were reused.

• Computational Structural Engineering : An International Journal
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• v.1 no.1
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• pp.1-9
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• 2001

Collapse behavior of Mission-Gothic Undercrossing under Northridge earthquake is studied by performing nonlinear time-history analysis and three-dimensional nonlinear finite element method for flared columns. Bridge structural model is characterized as three-dimensional with consideration of columns, superstructures, and abutment conditions. Three components of ground motion, corresponding to bridge's longitudinal, transverse, and vertical direction and their combinations are used to investigate bridge collapse. Studies indicate that bridge collapse is dominantly caused by transverse ground motion and the consideration of three-dimensional ground motion leads to a more accurate assessment. Failure mechanism of flared columns is analyzed applying nonlinear finite element method. Reduction of column capacity is observed due to orientation of flare. Further investigation demonstrates that the effects of flare play an important role in predicting of bridge failure mechanism. Suggestions are offered to improve the performance of bridges during severe earthquake.