• Journal of Institute of Control, Robotics and Systems
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• v.22 no.3
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• pp.177-185
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• 2016

This paper presents a method to design a controller for active suspension with 1-DOF decoupled models. Three 1-DOF decoupled models describing vertical, roll and pitch motions are used to design a controller in order to generate a vertical force, roll and pitch moments, respectively. These control inputs are converted into active suspension forces with geometric relationship. To design a controller, a sliding mode control is adopted. Frequency domain analysis and simulation on vehicle simulation software, CarSim$^{(R)}$, show that the proposed method is effective for ride comfort.

• Journal of the Korean Society for Precision Engineering
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• v.22 no.7 s.172
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• pp.102-111
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• 2005

In this paper, we address a position control for a parallel stage, which is levitated and driven by electric magnetic force. This consists of a levitating object (called platen) with 4 permanent magnetic linear synchronous motors in parallel. Each motor generates vertical force for suspension against gravity and propulsion force horizontally as well. This stage can generate six degrees of freedom motion by the vertical and horizontal force. A dynamic equation of the stage system is derived based on Newton-Euler method and it's special Jacobian matrix describing a relation between the limited velocity and Cartesian velocity is done. There are proposed two control methods for positioning which are Cartesian space controller and Actuator space controller. The control performance of the Cartesian space controller is better than the Actuator space controller in task space trajectory while the Actuator space controller is simpler than the Cartesian space controller in controller realization.

• Physical Therapy Korea
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• v.26 no.3
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• pp.57-66
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• 2019

Background: Visual and somatosensory integration processing is needed to reduce pusher behavior (PB) and improve postural control in hemiplegic patients with acute stroke. Objects: This study aimed to investigate the effects of game-based postural vertical training (GPVT) on PB, postural control, and activity daily living (ADL) in acute stroke patients. Methods: Fourteen participants with acute stroke (<2 months post-stroke) who had PB according to the Burke lateropulsion scale (BLS) (score>2) were randomly divided into the GPVT group ($n_1=7$) and conventional postural vertical training (CPVT) group ($n_2=7$). The GPVT group performed game-based postural vertical training using a whole-body tilt apparatus. while the CPVT group performed conventional postural vertical training to reduce PB (30 minutes/session, 2 times/day, 5 days/week for 3 consecutive weeks). The BLS was evaluated to assess the severity of PB. And each subject's postural control ability and ADL level were assessed using the postural assessment scale for stroke (PASS), balance posture ratio (BPR), and Korean-modified Barthel index (K-MBI). Outcomes were measured pre- and post-intervention. Results: Comparison of the pre- and post-intervention assessment results showed that both interventions led to the following significant changes: decreased severity of PB scores and increased PASS, BPR, and K-MBI scores (p<.05). In particular, statistical analysis between the two groups, the BLS score was significantly decreased in the GPVT group (p<.05). And PASS, BPR, and K-MBI scores were significantly improved in the GPVT group than in the CPVT group (p<.01, respectively). Conclusion: This study demonstrated that GPVT lessened PB severity and improved postural control ability and ADL levels in acute stroke patients.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.64-72
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• 2001

This paper describes an optimal design technology in a segment type vertical guide bearing for vertical rotating machinery. Segment type vertical guide bearings have widely used for vertical rotating machinery, however bearing problems, such as excessive vibration and temperature rise, frequently take place in the actual machine. Such excessive vibration magnitude and/or abnormal bearing metal temperature rise result in serious damage and economic losses. Thus the segment type vertical guide bearing should be designed to get optimal characteristics in order to maintain stable operation without bearing failure due to abnormal vibration and/or abnormal bearing metal temperature. The preload ratio is the most important parameter in designing the segment type vertical guide bearing. Because adjustment of the bearing preload by changing the bearing clearance could easily control both the bearing stiffness and the cooling effect. In the paper, the influence of the preload effects on the bearing metal temperature and the bearing stiffness has been investigated both theoretically and experimentally in order to find out an optimum preload ratio. Results show that the segment type vertical guide bearing has an optimum preload ratio at which the bearing stiffness reaches a masimum value while the bearing metal temperature is minimized.

• Journal of the Korea Institute of Military Science and Technology
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• v.17 no.5
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• pp.585-590
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• 2014

A permanent vertical magnetization should be obtained to counteract induced vertical magnetization due to the earth's background field during the Flash D demagnetization process. A vertical susceptibility is needed to calculate a extra-permanent magnetization, which is needed to control the permanent vertical magnetization in stage 2 of Flash D demagnetization and added to the final vertical permanent magnetization. Two susceptibilities were found in this paper. One is obtained from the extra-magnetization. The other is obtained by magnetic field measurement from the scaled physical vessel when the vessel is excited by vertical magnetic field. The initial susceptibility by the extra-magnetization was 0.101~0.109 and the one from the measured magnetic field was 0.122. Two susceptibilities have a good agreement each other. From this paper, it is found that the susceptibility is able to appllied to calculate the extr-magnetization.

• Journal of the Korea Computer Graphics Society
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• v.19 no.1
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• pp.21-25
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• 2013

In this paper, we consider a physics-based 2D flight simulation game where users can easily control realistic flight of a vehicle equipped with two thrusters that allow vertical takeoff and vertical landing. The flight vehicle can be manipulated by directly controlling the thrusting force at each thruster using a pair of analog input devices such as joysticks. However, it might require too much practice to make aerobatic flying solely with this kind of control. We propose a set of fly-by-wire methods that provide easy-to-use, intuitive control of a VTVL vehicle. Based on PD controllers, the proposed methods allow users to specify the velocity or position of the vehicle directly. Furthermore, they are easy to understand and simple to implement. We expect that the proposed vehicle model and control mechanism could be used in various 2D games.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.430-439
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• 2008

In this paper, we propose a sender-based TCP congestion control scheme for downward vertical handover (DVHO), in which mobile node moves from a cellular network to a wireless LAN. DVHO can give rise to severe performance problems in TCP throughput because it causes a drastic change of link characteristics. Particularly, TCP executes falsely congestion control by packet reordering, which is occurred from link delay difference between a cellular link and a wireless LAN link. Therefore, the congestion window is reduced. And unnecessary retransmissions wastes bandwidth. To solve these problems, we propose a method using estimated round-trip time in cellular link to process duplicated ACKs from reordering. Furthermore, the duplicated ACKs are used to the control congestion window size. Simulation result shows that the proposed scheme can solve problems. Moreover, the proposed scheme can have better performance than TCP New Reno and nodupack.

• The korean journal of orthodontics
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• v.49 no.5
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• pp.286-298
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• 2019

Objective: The objectives of this study were to evaluate linear and volumetric alveolar changes induced by nasoalveolar molding (NAM) in infants with complete unilateral cleft lip and palate (UCLP) and compare the maxillary dimensions after NAM with the normal dimensions in infants without clefts. Methods: A total of 26 infants with UCLP treated by NAM (mean age before and after NAM: $14.20{\pm}8.09days$ and $118.16{\pm}10.06days$, respectively) comprised the treatment group, while 26 infants without clefts (mean age: $115.81{\pm}8.71days$) comprised the control group. Changes in the maxillary dimensions following NAM were measured on three-dimensional models using Mimics software, version 17.0. Results: During NAM, there was a decrease in the cleft widths, maxillary arch depths, and rotation of the greater segment. While the anterior alveolar arch width exhibited a significant decrease, the posterior arch width was mostly maintained. There were no changes in the anterior vertical deviations of the alveolar segments. The alveolar crest lengths, arch circumference, and bilateral posterior volumetric measures exhibited an increase. After NAM, the anterior arch width was comparable between the treatment and control groups, whereas the posterior arch width and anterior vertical deviations were greater in the treatment group than in the control group. The maxillary arch depths, alveolar crest lengths, and maxillary volumes were smaller in the NAM group than in the control group. Conclusions: During NAM in infants with UCLP, the cleft width and anteroposterior and transverse alveolar dimensions exhibited a decrease while the vertical dimensions were maintained. Compared with infants without clefts, those with UCLP treated by NAM exhibited sagittal and vertical alveolar growth deficiencies and tissue insufficiency.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.1
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• pp.34-48
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• 2017

This study proposes a new approach to control a trajectory control of vertical type articulated robot arm with six revolution joints by computed torque method for manufacturing process automation. The proposed control scheme takes advantage of the properties of the fuzzy controllers. The proposed method is suitable to control of the trajectory and path control in cartesian space for vertical type articulated robot manipulator for forging manufacturing process automation. The results is illustrated that the proposed fuzzy computed torque controller is more stable and robust than the conventional computed torque controller. This study is included with an analytical methodology of inverse kinematic computation for 6 DOF manipulators. And an intelligent PID based on feed forward fuzzy control structure is applied to control the working path control with disturbances caused by uncertainty parameters of the manipulator dynamic model. Lastly, the validity of proposed is verified by simulations and experiments.

• Journal of Environmental Science International
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• v.27 no.5
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• pp.291-297
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• 2018

Vertical farming systems offer many advantages in urban spaces. They have also been proposed as an engineering solution to increase the productivity per unit area of cultivated land by extending crop production in the vertical dimension. However, soil water retention is a major constraint affecting the plant environment. This study analyzed the effects of growth environment of Tropaeolum majus and Fragaria spp., on the vertical farming system, by using four different types of cover material types including sphagnum moss (Control), a shading net (S.N.), multi-layered fabric (M.L.F.), and non-woven fabric (N.W.F.). The volumetric soil moisture contents and plant characteristics were investigated from May to September 2014. Plant materials were individually cultivated in hanging baskets measuring $30{\times}17{\times}17cm$, filled with a mixture of soil and perlite, and placed at 1.5m height. Each treatment was performed in quadruplicate and consisted of five plants, amounting to a total of 20 plants. The analysis indicated that different covers were associated with multiple functions and soil water retention improvements may have a positive impact on the vertical farming system. The difference in soil water retention increased in the following order: M.L.F. > Control > N.W.F. > S.N.. Furthermore, the differences in plant height and survival rate increased in the following order: M.L.F. > Control > N.W.F. > S.N. Therefore, M.L.F yielded satisfactory good response for the vertical farming system of cover materials. Our results clearly demonstrate that vertical spaces represent an attractive alternative to urban farming and suggest that further increases in yield may be achieved via different cover materials in vertical farming using hanging baskets.