• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.2
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• pp.168-174
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• 2017

In this work, a piezostack single-stage valve (PSSV) system is proposed and its control performance is experimentally evaluated at high temperature up to $150^{\circ}C$. In order to achieve this goal, a PSSV system is designed and operating principle and mechanical dimensions are discussed. A displacement amplifier and an adjust bolt are used to generate target displacement and to compensate thermal expansion. Then, an experimental apparatus is constructed to evaluate control performance of the PSSV system. The experimental apparatus consists of a heat chamber, a hydraulic circuit, a pneumatic circuit, pneumatic-hydraulic cylinders, thermal insulator, electronic devices, sensors, data acquisition (DAQ) board and a voltage amplifier. The flow rate and displacement control performance of the valve system are evaluated via experiment. The experimental results are evaluated and discussed at different temperatures and frequencies showing the controlled flow rate and spool displacement.

• Journal of Microbiology and Biotechnology
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• v.26 no.9
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• pp.1551-1556
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• 2016

Broiler meat production worldwide has been plagued by lethal food-poisoning bacteria diseases, including listeriosis. A fatality rate of 15.6% was recorded in human beings in the EU in 2015. During 2013, a total of 200 poultry farm samples, including litter, chicken breast, farm feed, and drinking water, were collected to generate baseline data for the characterization of the genus Listeria in broiler poultry farms. Listeria spp. were detected in a total of 95 (47.5%) poultry farm samples. The isolates of Listeria spp. included L. innocua (28.5%), L. ivanovii (12.5%), L. welshimeri (4.5%), and L. monocytogenes and L. seeligeri (1% each). Listeria spp. contamination rates were higher in farm feed (70%), followed by litter (52.5%), chicken breasts (42.2%), and drinking water (10%). Almost all Listeria spp. isolates were resistant to more than three classes of antibiotics (multidrug resistant). Besides this, we observed a significant resistance level to penicillin and fluoroquinolone drugs. However, lower resistance levels were recorded for broad-spectrum cephalosporins. The inlA, inlC, and inlJ virulence genes were detected in almost all of the L. monocytogenes isolates. Thus, food safety management approaches and interventions at all stages of the broiler rearing cycle were needed to control cross-contamination and the zoonotic potential of listeriosis.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.239-247
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• 2017

The purpose of this study is to develop a motion generation technique based on a double inverted pendulum model (DIPM) that learns and reproduces humanoid robot (or virtual human) motions while keeping its balance in a pattern similar to a human. DIPM consists of a cart and two inverted pendulums, connected in a serial. Although the structure resembles human upper- and lower-body, the balancing motion in DIPM is different from the motion that human does. To do this, we use the motion capture data to obtain the reference motion to keep the balance in the existence of external force. By an optimization technique minimizing the difference between the motion of DIPM and the reference motion, control parameters of the proposed method were learned in advance. The learned control parameters are re-used for the control signal of DIPM as input of linear quadratic regulator that generates a similar motion pattern as the reference. In order to verify this, we use virtual human experiments were conducted to generate the motion that naturally balanced.

• The Journal of Korea Robotics Society
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• v.12 no.2
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• pp.206-216
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• 2017

This paper proposes a method to simultaneously estimate two degrees of freedom in wrist forces (extension - flexion, adduction - abduction) and one degree of freedom in grasping forces using Electromyography (EMG) signals of the forearms. To correlate the EMG signals with the forces, we applied a multi - layer perceptron(MLP), which is a machine learning method, and used the characteristics of the muscles constituting the forearm to generate learning data. Through the experiments, the similarity between the MLP target value and the estimated value was investigated by applying the coefficient of determination ($R^2$) and root mean square error (RMSE) to evaluate the performance of the proposed method. As a result, the $R^2$ values with respect to the wrist flexion-extension, adduction - abduction and grasping forces were 0.79, 0.73 and 0.78 and RMSE were 0.12, 0.17, 0.13 respectively.

• Proceedings of the KIEE Conference
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• 2007.11c
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• pp.175-178
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• 2007

This paper is presented for the design of the thrust yoke for the spindle motors. HDD spindle motors are rotated by fluid dynamic bearing which consists of the shaft and the sleeve with the groove to generate the pressure. Because the thrust and journal clearances between shaft and sleeve is too small, around 8um and 2.5um, respectively, it is very difficult to design the bearing to come up to the disks to read and write the data. By the way, it is also so hard to overcome the load of the disks with only the thrust bearing. So, the paper is proposed for the trust yoke to come up to the disks considering of the force of the thrust bearing. In this paper, we proposed the thrust yoke with an unique fluid dynamic bearing in comparison with the motors without thrust yoke. Experimental results show the performance of the thrust yoke of the spindle motors for an HDD.

• IE interfaces
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• v.24 no.3
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• pp.220-230
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• 2011

The multi-reservoir operation problem for efficient utilization of water resources involves conflicting objectives, and the problem can be solved by varying weight coefficient on objective functions. Accordingly, decision makers need to choose appropriate weight coefficients balancing the trade-offs among multiple objectives. Although the appropriateness of the weight coefficients may depend on the total amount of water inflow, reservoir operating policy may not be changed to a certain degree for different hydrological conditions on inflow. Therefore, we propose to use fuzzy Data Envelopment Analysis (DEA) to rank the weight coefficients in consideration of the inflow variation. In this approach, we generate a set of Paretooptimal solutions by applying different weight coefficients on Coordinated Multi-reservoir Operating Model. Then, we rank the Pareto-optimal solutions or the corresponding weight coefficients by using Fuzzy DEA model. With the proposed approach, we can suggest the best weight coefficients that can produce the appropriate Pareto-optimal solution considering the uncertainty of inflow, whereas the general DEA model cannot pinpoint the best weight coefficients.

• Korean Journal of Cognitive Science
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• v.22 no.3
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• pp.327-345
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• 2011

In this paper, a new approach to Korean POS (Part-of-Speech) tagging is proposed. In previous works, a Korean POS tagger was regarded as a post-processor of a morphological analyzer, and as such a tagger was used to determine the most likely morpheme/POS sequence from morphological analysis. In the proposed approach, however, the POS tagger is supposed to generate the most likely morpheme and POS pair sequence directly from the given sentences. 398,632 eojeol POS-tagged corpus and 33,467 eojeol test data are used for training and evaluation, respectively. The proposed approach shows 96.31% of POS tagging accuracy.

• Earthquakes and Structures
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• v.12 no.6
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• pp.629-641
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• 2017

Foundation plays a significant role in safe and efficient turbo machinery operation. Turbo machineries generate harmonic load on the foundation due to their high speed rotating motion which causes vibration in the machinery, foundation and soil beneath the foundation. The problems caused by vibration get multiplied if the soil is poor. An improperly designed machine foundation increases the vibration and reduces machinery health leading to frequent maintenance. Hence it is very important to study the soil structure interaction and effect of machine vibration on the foundation during turbo machinery operation in the design stage itself. The present work studies the effect of harmonic load due to machine operation along with earthquake loading on the frame foundation for poor soil conditions. Various alternative foundations like rafts, barrette, batter pile and combinations of barrettes with batter pile are analyzed to study the improvements in the vibration patterns. Detailed computational analysis was carried out in SAP 2000 software; the numerical model was analyzed and compared with the shaking table experiment results. The numerical results are found to be closely matching with the experimental data which confirms the accuracy of the numerical model predictions. Both shake table and SAP 2000 results reveal that combination of barrette and batter piles with raft are best suitable for poor soil conditions because it reduces the displacement at top deck, bending moment and horizontal displacement of pile and thereby making the foundation more stable under seismic loading.

• Asian Journal of Business Environment
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• v.6 no.3
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• pp.11-14
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• 2016

Purpose - Microfinance institutions (MFIs) in Bangladesh have been providing savings services to their clients at least for the past 15 years. However, whether an MFI should have institutional requirement(s) to be a deposit-taker generates interest among academics and policy makers. Thus, this short note aims to provide a brief overview of institutional properties of MFIs. Research Design, Data, and Methodology - This study used the existing literature and reports by the Microcredit Regulatory Authority' to investigate institutional properties of MFIs. In doing so, we have used 'institutional theory of saving' as a theoretical ground. Although the 'institutional theory of saving' has several important properties, the existing literature mostly discusses seven features such as information, incentives, facilitation, expectation, access, restrictions and security. Results - It is found that MFIs- in general- should have all the seven important institutional properties to be considered as an ideal savings institution. With regards to the microfinance sector in Bangladesh, this study supports that all the NGO-MFIs have these properties to be considered as an ideal deposit taker. Conclusions - The microfinance sector in Bangladesh needs to design and develop comprehensive and customer friendly savings products to further motivate the poor to save in MFIs.

• Journal of Research and Publication Ethics
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• v.1 no.1
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• pp.17-22
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• 2020

Purpose: This study is to develop managerial implications for JSAS for advancing to highly qualified journal and achieving its goals. Furthermore, the study sough to deduce implications of ethical issues of JSAS and to generate insights and future directions for JSAS management. Research design, data and methodology: This study employed a qualitative approach to review the current status of JSAS including its aims, managerial strategies and ethical systems. The study discussed ethical issues about fake journals and predatory journals to analyze the current states of JSAS's ethical system and to compare with each other. Results: Results indicated that JSAS has abided ethical requirements of common journals and established strict criteria, yet it should continuously observe blind peer-review systems to avoid unnecessary risks of being perceived as predatory journals. The rigorous ethical obedience will help JSAS to effectively perform its managerial strategies and to achieve its goals: Increasing submissions, inviting prestigious scholars to board member, and advance to high quality of journal. Conclusions: Continuous efforts of JSAS for ethical management is the most effective method to move to a high qualified international journal with reputation in academia. With the consideration of Korean journal society, ethical studies need to be further conducted.