• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.1
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• pp.95-100
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• 2005

Making the best use of the features of the electro-rheological(ER) valve, a two-port pressure control valve using ER fluids is proposed and manufactured. The ER-Valve characteristics are evaluated by changing the intensity of the electric field and the number of electrode. In addition, the performance of the plate type ER-Valve is investigated by change the particle concentration of the ER fluid. As only with electrical signal change to the ER-Valve in which ER fluid flowing, ER fluid flow is controlled, so development of simple ER-Valves have been tried. The ER-Valves and pressure drop check method are considered to be applied to the fluid power control system. Using the minかnぉd pressure control valve, a one-link manipulator with FHA in robot system is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuator. If it applies characteristics of the ER fluids, it will be able to apply in the control system fir the ER Valve which occurs from industrial controller(PLC).

• Journal of the Korea Institute of Military Science and Technology
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• v.24 no.5
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• pp.475-481
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• 2021

The on-board processor of satellite Synthetic Aperture Radar(SAR) digitizes the back-scattered echoes and transmits them to the ground. As satellite SAR image of various operating conditions including broadband and high resolution is required, an enormous amount of SAR data is generated. Decimation filter is used for data compression to improve the transmission efficiency of these data. Decimation filter is implemented with the FIR(Finite Impulse Response) filter and here, the decimation ratio and tap length are constrained by resource requirements of FPGA used for implementation. This paper suggests to use a non-integer ratio decimation filter in order to optimize the data transmission efficiency. Also, it proposes a filter design method that remarkably reduces the resource constraints of the FPGA in-use via applying a polyphase filter structure. The required resources for implementing the proposed filter is analysed in this paper.

• Fourth Industrial Review
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• v.1 no.1
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• pp.31-40
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• 2021

Purpose - According to the importance of business simulation learning as a new type of business learning tool, this study reviews the dimensions of business education and a brief history of business education simulation. At the end Capsim strategic management simulation program is introduce with its feature. Research design, data, and methodology - This study has been analyzed in a way that reviews at previous literature on simulation learning and looks at examples and features of Capsim simulation, online business simulation tools which has been used in the global market. Result - Capsim simulations are designed to offer focused opportunities for deep practice. That's why they are often more effective than passive tools such as textbooks, videos, or lectures. By the way, 'deep practice' is very different from 'ordinary practice'. After commuters who drive to school or work can accumulate thousands of hours of driving, but that doesn't make them expert drivers. The key to deep practice is self-awareness. That is, paying attention to what you are doing well and not so well. This is so important to learn that scientists use a specific term for it: 'metacognition', or thinking about the way you think and learn. Conclusion - The use of business simulation learning, such as Capsim, which is a given case, can create similar local systems by potentially engaging a large number of users in the virtual market. It could also be used as an individual to complete business training for students and those who are active in the business field of business.

• Korean Journal of Heritage: History & Science
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• v.49 no.4
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• pp.96-113
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• 2016

The observation of the classic plant name 'Hwe', that is to be discussed in this thesis, must be primarily conducted in folk plant research made through old documents. Diverse information such as the characteristics, method of use, and distribution of plants is scattered in old documents. However, reviews of classic plant names should be made to use such information. This is because information on plants can only be used after thorough verifications are made of the plant names. 'Hwe' is interpreted as various meanings in Korea but it is mostly used to mean fir, old pine tree, and cypress. However, it is not known by what standards such interpretations have been made. In particular, 'Hwe' is interpreted at the discretion of the translator in classic translations, so direct quotations from these lead to further errors. Therefore, items in classic plant names must be reviewed again. Why is 'Hwe' interpreted in various ways as a plant name and according to what standards should it be interpreted? This study was conducted with these questions. Also, the significance of this study is placed in the setting of guidelines for the interpretation of 'Hwe' so that classic plant names can be properly interpreted and information on plants can be accurately secured.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.59
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• pp.27-57
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• 2013

Traditionally construction has been an industry that favoured ADR over formal litigation due to the complexity of technical issues. However, over the past decade construction arbitration has come under increasing attack for its rising costs and growing delays, and expansion of arbitration processes to the point that those processes are approaching the more complex and formal processes followed to resolve disputes litigation. As a result, parties are looking for new methods of resolving their disputes in a more efficient and economical manner, such as ODR. A review of the history of ODR and the practical applications of ODR in use today lead to the conclusion that the concept of ODR for construction dispute resolution appears to be possible and realistic. The advantages seem to outweigh the disadvantages, especially given the solutions suggested to overcome many of the disadvantages. While ODR may not be a realistic venue for large complex construction cases, it may be just the ideal venue for smaller and simple construction disputes. In conclusion, given the advantages that ODR arbitration does offer, the most realistic use of ODR in the short term would involve disputes consisting of a simple, one-dimensional dispute within which the parties can stipulate to the facts in the case. In such simple disputes ODR may be not only an appropriate vehicle within which the dispute can be resolved; it might be more easily accepted by the parties as the preferred platform for resolution. Hopefully, international institutions of arbitration will be successful in their development of a international standards and platform fir disputes that can be adapted for use in construction and will serve as the first step in developing ways to handle small construction claims, thereby allowing parties to resolve their disputes in a faster and more economical manner.

• Journal of the Korea Furniture Society
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• v.28 no.2
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• pp.111-117
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• 2017

Recently, as people's interest in wood has increased, the use of wood as household and landscape decking materials has increased. As the deck material, imported wood such as synthetic wood, Ipe, and Malas was used in addition to the existing preserved wood, but recently deck use has been activated as part of the activation of domestic materials. As an important quality factor in the selection of such decking materials, various durability along with weatherability for long - term use is required for maintenance. Generally used tropical hardwoods have excellent weatherability and durability without additional preservative treatment. However, the domestic larch is a wood species with a higher specific gravity and durability than ordinary conifers. However, it has not yet been used as a deck material due to lack of comparative studies on its characteristics. Therefore, hardness and durability of wood were measured using six specimens of Ipe, Massaranduba, Malas, Douglas-fir, Larch and Torrefied-Larch. Density Profile was used to measure the density, and Brinell hardness test and resistance test against momentary impact were carried out for the test of resistance to static load. Also, The hardness and durability of wood were measured by castor test with resistance test against dynamic load, as well as, nail down test by experiment on surface hardness and durability. As a result of the experiment, the hardness was increased in proportion to the density, and it was confirmed that the imported lumber was harder and durable than the domestic larch.

• Journal of the Korean Wood Science and Technology
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• v.48 no.2
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• pp.245-252
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• 2020

This study was performed to analyze the mechanical properties of tropical hybrid cross-laminated timber (CLT) with bamboo laminated board as the core layer in order to evaluate the possibility of its use as a CLT material. Bamboo board was used as the core layer and the tropical species Acacia mangium willd., from Indonesia, was used as the lamination in the outer layer. The modulus of elasticity (MOE), modulus of rupture (MOR), and shear strength of the hybrid CLT were measured according to APA PRG 320-2018 Standard for Performance-Rated Cross-Laminated Timber. The results show that the bending MOE of the hybrid CLT was found to be 2.76 times higher than SPF (Spruce Pine Fir) CLT. The reason why the high MOE value was shown in bamboo board and hybrid CLT applied bamboo board is because of high elasticity of bamboo fiber. However, the shear strength of the hybrid CLT was 0.8 times lower than shear strength of SPF CLT.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.3
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• pp.150-159
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• 2000

In-process diagnosis of the cutting state is essential for the automation of manufacturing systems. Especially when the cutting process becomes unstable it induces self-exited vibrations a frequent case of poor tool life rough surface finish damage to the workpiece and the machine tool itself and excessive down time. To ensure that the cutting process main-tains stable it is highly desirable to have the capability of real-time. To ensure that the cutting process main-tains stable it is highly desirable to have the capability of real-time monitoring and controlling chatter. This paper describes the detection method of chatter vibration using cutting force in turning process. In order to detect a chatter vibra-tion the dynamic fluctuation of radial force is analyzed since this components is sensitive to the chatter. The envelope sig-nal of radial force has been calculated by the use of FIR Hilbert transformer and it was useful to classify the chatter signal from the dynamically unstable circumstances. It was found that the mode and the mode width were closely correlated with the chatter amplitude was well. Finally back propagation(BP) neural network have been applied to the pattern recognition for the classification of chatter signal in various cutting conditions. The validity of this systed was confirmed by the experiments under the various cutting conditions.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.11 no.1
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• pp.32-38
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• 2000

Background and Objectives : Voice therapy has been used as a viable adjuvant to surgery and pharmacological therapy fir the management of voice disorders. The singing voice features a special brand of emotion, intensity, and energy so successful therapeutical approach requires the doctor is able to involve himself into the physical and psychic condition and artistic usage of the voice. The purpose of this study was to evaluate the effect and utility of singing therapy as an initial treatment for classically trained singers with voice disorders. Material and method : Twenty-one male and fifty-five female classic singers with voice disorders were treated with singing therapy. At first, abdominal breathing, resonant phonation, and relaxation method was trained, then after accessing each patient's singing abilities, treatment methods for each specific problems was applied. The results were compared according to age, sex, treatment duration, part, laryngeal pathology, patient subjective evaluation, perceptual evaluation of voice, and maximal phonation time. Results : Patients subjective evaluation, perceptual evaluation, pathologic findings of larynx, maximal phonation time showed superior results after singing therapy. Conclusion : Singing therapy changes the mode of respiration and phonation and enhances the vocal function and improves the laryngeal pathology, The result of this study indicate that singing therapy is an effective treatment method that laryngologists can use for classical singers with voice disorders.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.9
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• pp.679-691
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• 2003

The band-width of disk drive servo system is rapidly increasing for the robustness to external disturbance as the track density is increasing. The increase of the band-width may cause mechanical resonance of an actuator. In disk drive servo system, a notch filter is usually used to suppress the mechanical resonance of the actuator. However, the resonance frequency differs from drive to drive because of manufacturing tolerance and varies with temperature even within a single drive. The variation of resonance frequency degrades the suppression performance of the notch filter. In this paper, we present an adaptive digital notch filter that identifies the resonance frequency of the disk drive servo actutaor precisely and adjusts automatically its center frequency. For this, we design an adaptive FIR digital filter for the estimation of the resonance frequency. The estimation filter identifies the resonance frequency adaptively using the output signal generated from the servo system, which is excited with an excitation signal including all the expected resonance frequency components. We prove mathematically the convergence of the resonance frequency estimation filter. Furthermore, in order to demonstrate the practical use of our work, we present some experimental results using a commercially available disk drive.