• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.771-780
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• 2010

This paper describes the design process of a six-component force/torque (F/T) sensor. The new six-component F/T sensor having leaf spring ends has been developed using a cross beam structure as the basic sensing element. Fundamental strain analysis of both ends fixed beam having a leaf spring structure is performed by finite element analysis. In order to obtain similar output sensing strains from the six component loads and minimize coupling strains, the optimal location of strain gages is determined and the strain gages are connected so that the bridge circuits with four strain gages would be balanced. Using leaf spring ends instead of rigid fixed ends, remarkable increment in output sensing strain can be achieved for two component forces. Several modifications in design result in a similar sensing strain of approximately $400\;{\mu}m/m$ for the six-component forces and moments, and a reduced coupling strain of $0\;{\mu}m/m$ between the forces and moments.

• Computational Structural Engineering
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• v.5 no.3
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• pp.97-103
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• 1992

Since many design problems in the railroad, aerospace and machine structures involve considerations of the effect of cyclic loading, manufacturing and quality control processes much fully account for fatigue of critical components. Due to the sensitivity of the Paris law, it is very important to calculate .DELTA.K numerically to minimize the error of predicted fatigue life in cycles. However, it is shown that the p-version of FEM based on LEFM analysis is far better suited for computing the stress intensity factors than the conventional h-version. To demonstrate the proficiency of the proposed scheme, the welded T-joint with crack problems of box car body bolster assembly and a crack problem emanating from a circular hole in finite strip have been solved.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.10
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• pp.2150-2158
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• 2002

A recent research and development has the requirement for the optimization to shorten design time of modified or new product model and to obtain more precise engineering solution. General optimization problem must consider many conflicted objective functions simultaneously. Multi-objective optimization treats the multiple objective functions and constraints with design change. But, real engineering problem doesn't describe accurate constraint and objective function owing to the limit of representation. Therefore this study applies variance analysis on the basis of structure analysis and DOE to the vertical roller mill fur portland cement and proposed statistical design model to evaluate the effect of structural modification with design change by performing practical multi-objective optimization considering mass, stress and deflection.

• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.6
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• pp.729-736
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• 2015

In this paper, It was performed to optimize for the deck's structural design of a double ended car ferry ship respect to Goal-Driven Optimization (GDO). It was examined for the strength and deformation of the deck and determined to save economic cost the optimal point. The deck thickness based on the Design of Experiments (DOE) and response surface method was increased to 110%. and can improve the deck's strength and stiffness. By performing the regression analysis respect to the result, we propose the optimal regression model formula as a third degree polynomial regression models. The coefficient of determination $R^2$ was about 0.98 and reliability could be obtained.

• Journal of vocational education research
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• v.29 no.3
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• pp.107-132
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• 2010

The purpose of this study was to investigate the effects of learning achievement by comparing project approach group and the control group on the unit of growing flowers and vegetables in practical arts education. For this purpose, the experimental study on the unit of growing flowers and vegetables was achieved with 63 students(5th grade 2 classes) in S elementary school. The project approach model (Chung, Sung-bong) was applied to the experimental group, and the traditional model to the control group. To verify the effects of each class, nonequivalent control group post test-only design was applied 10 times. The SPSSWIN(ver 12. 0. 1) was used for analyzing the frequency and t-tests. The results of this study were as follows ; First, there was significant effect of learning achievement(cognitive domain) in the project approach groups. In addition, learning achievement of the experimental group has been showed significant difference about intellectual function and ability but not about knowledge. Second, there was significant effect of learning achievement(psychomotor domain) in the project approach groups. In other words, there has been showed significant difference in basic skill and integrated skill for growing flowers and vegetables but not in elemental skill for planting. Third, as the post test, there existed significant effect(affective domain) in the project approach groups. In other words, there was a meaningful difference in acceptance, value, belief, actualization but not in interest. Based on these results, It is believed that the project approach model in the unit of 'growing flowers and vegetables' is more effective than the traditional learning method in learning achievement of learners' cognitive, psychomotor and affective domain.

• The Journal of the Korea Contents Association
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• v.18 no.4
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• pp.164-177
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• 2018

As the market for IoT devices grows, it is expected that the scale of malware attack will be considerable. Accordingly, the improvement of related legislation has been actively promoted, the recently strengthened Information and Communication Network Act was enforced. Because IoT related accidents can lead to not only financial damages but also human accidents, IoT device Security has been attracted a great deal of attention. In this paper, IoT devices provide essential security functions through legal and technical perspectives, and analyze related technologies. This can be used to a reference for the Start-up developer and IoT device designer.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.523-528
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• 2008

The accurate distribution of flow rate has been a very important part to control the air change rate since introduction of house ventilation system. An inappropriate selection of fan due to incorrect prediction of pressure loss in duct brings energy loss. In the previous study the pressure loss of general spiral duct was measured and database was constructed for finding correct loss factors in fitting upper stream. The purpose of this study is to compare and investigate the error range of flow rate by applying T-Method to bilateral symmetry and asymmetry layout of duct. The results of this study are as following. It is demanded to decide accurate size under duct design for house ventilation system. Because the small amount of Flow rate was considered at that time. The error range was 3.17% on case1 and 3.52% on case2. The error range difference was 0.35%.

• Journal of the Society of Naval Architects of Korea
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• v.33 no.2
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• pp.56-64
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• 1996

In this study, a review is made of the previous work(Ref. 1 and 5) for the development of the limit design method of the flat rectangular grillages under the lateral pressure. And the effect of the in-plane loads on the collapse theory is considered. The main part of the work is devoted in developing the standard design method of grillages under the criteria of minimum weight and minimum cost. In the final part, it was shown that Pareto solution methods can be easily applied to structural optimization with the multiple objectives, and the designer can have an appropriate choice from those Pareto optimal solutions.

• The Journal of the Korea Contents Association
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• v.15 no.12
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• pp.459-470
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• 2015

In this study, we have developed a retirement coaching model for effective retirement planning by applying systematic conversation of the coaching technique. A draft of the retirement coaching model was complemented by the validity verification of experts. The retirement coaching model can be summarized as follows. The first step, rapport and empowerment(RE), consists of sharing the image of a happy retirement after establishing a rapport between the coach and the people wanting to prepare for retirement. The second step, target establishment(T), consists of setting the theme and goals of the conversation. The third step, identification(I), consists of developing a retirement plan for achieving the established goals. The fourth step, realization(R), consists of establishing a concrete schedule and a method of retirement planning. The fifth step, evaluation(E), consists of sharing impressions during coaching sessions, which facilitates future action plans.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.2
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• pp.92-100
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• 2002

The 16-port feed waveguide array with inductive walls analyzed by Galerkin's method of moments are proposed for the DBS reception system mounted on vehicle. First of all, in order to verify the validity of electromagnetic analysis and design for a $\pi$-junction feed waveguide, it is designed and fabricated at DBS band. The measurement results of a $\pi$-junction feed waveguide agree well with the theoretical ones. Based on this design method, an array design for WR-90 standard waveguide is conducted. Since the width of a $\pi$-junction feed WR-90 standard waveguide is larger than a guided wave length in an array design, the difference of amplitude and phase of 8-port array are calculated 2.3 dB and 62 degrees, respectively. The bandwidth with return loss of -20 dB below is about 220 MHz and it doesn't satisfy DBS band. To solve this problem, we propose a novel design that the width of a $\pi$-junction feed waveguide equals to a guided wave length. By the proposed novel design for 8-port feed waveguide array, the difference of amplitude and phase are decreased 1 dB and 13 degrees, respectively. The broad bandwidth of 700 MHz is also realized. The size of 16-port waveguide away compared with WR-90 array is reduced about 10 cm. The measured antenna gain for the fabricated 16-port feed waveguide array is observed 24 dBi above at DBS band.