• Journal of the Institute of Electronics Engineers of Korea CI
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• v.48 no.1
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• pp.44-50
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• 2011

We propose a multi-class AdaBoost algorithm for en efficient classification of multi-class data in this paper. Traditional AdaBoost algorithm is basically a binary classifier and it has limitations when applied to multi-class data problems even though multi-class versions are available. In order to overcome the problems on the AdaBoost algorithm for multi-class classification problems, we devise an AdaBoost architecture with a training algorithm that utilizes multi-class classifiers for its weak classifiers instead of series of binary classifiers. Experiments on a image classification problem using collected Caltech Image Database are preformed. The results show that the proposed AdaBoost architecture can reduce its training time while maintaining its classification accuracy competitive when compared to Adaboost.M2.

• Journal of Korean Elementary Science Education
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• v.29 no.1
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• pp.102-111
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• 2010

This study examined the instructional influences of MBL programs on elementary school students' science achievement, scientific inquiry skills, and science learning motivation. The perceptions of students and their teacher toward science classes using MBL programs were also examined. The subject of this study was sixty four 4th grade students from two classes. The experimental group engaged in science classes that applied MBL and the control group engaged in traditional science classes based on the textbook and experiment workbook. As results, there was no significant difference in academic achievement, scientific inquiry skills, however, were significantly higher for the experiment group compared to the control group. There was also significant difference in the relevance and confidence, the sub-categories of science learning motivation. In the analyses of students' perceptions toward science classes using MBL, students showed positive perceptions in aspects of interests of science classes, content comprehension, and convenience of experiments. The teacher also showed positive perceptions using MBL in elementary science classes. Educational implications of appling MBL in elementary science classes were discussed.

• Journal of the Korean housing association
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• v.27 no.3
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• pp.11-22
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• 2016

In Germany, during the modern architectural movements diverse experiments for the propagation of modern housing solutions were conducted that succeeded to the spirit of Bauhaus. Therefore, the study traced how Walter Gropius adopted the trends of architectural style and aesthetic, the concept of production, the concept for new typology of housing, and issues in urban architecture. According to the results, processes to the 'sachlich' style could be seen in the cases of early and latter works of detached houses and further aesthetic changes of later works. Second, Gropius expanded his design field from detached houses to multiple dwelling and it was accompanied by typological transformation of buildings considering the industrialization and production of housing. Third, in the cases of multiple dwelling, it could be identified that site planning of housing complexes and building arrangement reflected a shift from traditional urban pattern to new alternatives suitable for mass housing supply. Thus, changes in the genealogy and propensity of German residential designs were partly summed up and their implications on modern housing architecture were discussed.

• Journal of the Korean housing association
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• v.25 no.3
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• pp.165-179
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• 2014

The purpose of this study was to draw application elements of housing interior design according to user-oriented sensibility types. The sensibility evaluation experiments were conducted to target the general user 118 people using the sensibility evaluation tool for housing interior space. The results of the analysis were as: To produce the 'cozy' space, the colors and materials giving soft and natural feeling should be used. For the 'practical' space, type of ceiling and window that give the visually open feeling, the user-oriented furniture arrangement that allows using the space efficiently. For the 'cheerful' space, the simple and natural effects should be produced by using closed space that stable. For the 'traditional' space, the natural fishing material having rough texture should be used. For the 'unique' space, the space contained the dynamic feeling by the diagonal or vertical line and the graphic expression in the wall. For the 'congenial' emotional space, basic is the symmetric, stable and simple space. On the other hand, for the material, small size, natural texture or typical and soft materials should be used. For the 'sensuous' space, the dynamic and vertical sense of space should be expressed by the type of ceiling. The most important elements for the space of 'gorgeous' sensibility, is the color.

• Journal of the Korean Society of Safety
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• v.24 no.2
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• pp.7-12
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• 2009

The machining process of ceramics can be characterized by cracking and brittle fracture. In the machining of ceramics, edge chipping and crack propagation are the principal reasons to cause surface integrity deterioration. Such phenomenon can cause not only poor dimensional and geometric accuracy, but also possible failure of the ceramic parts. Thus, traditional ceramics are very difficult-to-cut materials. Generally, ceramics are machined using conventional method such as grinding and polishing. However these processes are generally costly and have low MRR(material removal rate). To overcome such problems, in this paper, h-BN powder, which gives good cutting property, is added for the fabrication of machinable ceramics by volume of 10 and 15%. The purpose of this study is an analysis of endmill's rake angle for appropriate tools design and manufacturing for the machinable ceramics. In this study, Experimental works are executed to measure cutting force, surface roughness, tool fracture, on different axial rake angle of endmills. Cutting parameters, namely, feed, cutting speed and depth of cut are used to accomplish purpose of this paper. Required experiments are performed, and the results are investigated.

• Journal of The Institute of Information and Telecommunication Facilities Engineering
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• v.9 no.3
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• pp.92-101
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• 2010

Energy efficiency and safe mobility are the two key constituents of the future automobile. The technologies that enable these features are now heavily dependent upon information and communication technology rather than traditional auto-mechanical technology. This paper presents an exploratory project 'Smart&Green Vehicle Project' at Western Michigan University which is to improve the geographical location accuracy of vehicles and to study various applications of making such location data available. Global Positioning System (GPS), Inertial Navigation System (INS), Vehicular Ad-hoc Network (VANET) technology, and data fusion among these technologies are investigated. Testing and evaluation is done on systems which will gather vehicular positioning data during GPS signal loss. Vehicles in urban settings do not acquire accurate positioning data from GPS alone; therefore there is a need for exploration into technology that can assist GPS in urban settings. The goal of this project is to improve the accuracy of positioning data during a loss of GPS signal. Controlled experiments are performed to gather data which aided in assessing the feasibility of these technologies for use in vehicular platforms.

• Membrane and Water Treatment
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• v.8 no.1
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• pp.19-34
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• 2017

Boron exists in dilute concentrations in sea water, ground water and waste waters. Reactive liquid extraction can be used for removing boron to make the treated water suitable for drinking and irrigation, with its final concentration less than 0.5 ppm. The results of equilibrium experiments are reported on the removal of boron using 2-butyl-2-ethyl-1, 3-propanediol (BEPD as a nonionic carrier) in sunflower oil, a non-traditional solvent. The results of removal of boron from aqueous solutions in the concentration range 0.5-20 ppm are presented. It is shown that this new liquid membrane system, is able to remove boron from ground waters at their natural pH of 6-8 (without any chemical addition for pH adjustments). The removal efficiency is good when the process is upgraded to a hollow-fibre membrane contactor and approximately 45% boron can be removed in a single-stage contact. There are additional advantages of this new approach that includes reduced operational health and safety and environmental issues. The results reported here provide guidelines to the development of boron removal process using renewable, biodegradable, safe and cheap solvent system such as sunflower oil.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.375-381
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• 2004

Recently, the evolution in production techniques (e.g. high-speed milling) and the complex shapes involved in modem production design has been increasingly popular. The key to the achievement is a drastic improvement of the dynamic behavior of the machine tool axes used in production machinery. The more complex these tool paths the higher the speed and acceleration requirements. But it is very difficult to reach the target for high speed machine tool because of the limitations of servo system and motion control system. However the direct drive design of machine tool axes, which is based on linear motors and which recently appeared on the market, is a viable candidate to meet the ever increasing demands, because of these advantages such as no backlash, less friction, more mechanical simplicity and very higher acceleration and velocity comparing to the traditional system. This paper focused on the performance tests of the high speed horizontal machine tool based on linear motor. Especially, dynamic characteristics were investigated through circular test and circular form machining test is carried out considering many important parameter. Therefore these several experiments is used to be evaluated the model for prediction of circular motion error and circular machined error.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.1
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• pp.56-62
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• 2015

Using an optical 3D scanning device to collect data from a diffused reflection surface is very difficult. To solve this problem, there are many applications including a spray-type developer and silicon molds. However, using a developer can cause chemical reactions between objects and particles of the developer and uneven surfaces on the object. To overcome these problems, we suggest an electrostatic powder coating method for even coating of particles onto surfaces for collecting 3D shape data. We have developed an automatic, electrostatic powder-coating machine and performed three different experiments to compare this system with a laser interferometer and a T-scan 3D scanner. As a result, we could ascertain the various characteristics of this new method, including good sensitivity for the various surface states of the bare surface, developer, and electrostatic powder coating. Finally, we verified the outstanding scanning performance and were able to demonstrate that this method achieves quality than traditional methods.

• Smart Structures and Systems
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• v.19 no.5
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• pp.499-512
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• 2017

Traditional structural dynamic analysis and Structural Health Monitoring (SHM) of large scale concrete civil structures rely on manufactured embedding transducers to obtain structural dynamic properties. However, the embedding of manufactured transducers is very expensive and low efficiency for signal acquisition. In dynamic structural analysis and SHM areas, piezoelectric transducers are more and more popular due to the advantages like quick response, low cost and adaptability to different sizes. In this paper, the applicable feasibility assessment of the designed "artificial" piezoelectric transducers called Concrete Piezoelectric Smart Module (CPSM) in dynamic structural analysis is performed via three major experiments. Experimental Modal Analysis (EMA) based on Ibrahim Time Domain (ITD) Method is applied to experimentally extract modal parameters. Numerical modal analysis by finite element method (FEM) modeling is also performed for comparison. First ten order modal parameters are identified by EMA using CPSMs, PCBs and FEM modeling. Comparisons are made between CPSMs and PCBs, between FEM and CPSMs extracted modal parameters. Results show that Power Spectral Density by CPSMs and PCBs are similar, CPSMs acquired signal amplitudes can be used to predict concrete compressive strength. Modal parameter (natural frequencies) identified from CPSMs acquired signal and PCBs acquired signal are different in a very small range (~3%), and extracted natural frequencies from CPSMs acquired signal and FEM results are in an allowable small range (~5%) as well. Therefore, CPSMs are applicable for signal acquisition of dynamic responses and can be used in dynamic modal analysis, structural health monitoring and related areas.