• Journal of the Korean Wood Science and Technology
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• 제48권6호
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• pp.869-877
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• 2020

The power consumption in the low consistency (LC) refining is an important indicator for the optimal control of the process and it is composed of the net power and the no-load power. The refining efficiency and process characterization of LC refining are directly affected by power consumption. In this paper, the effect of pulp consistency and average fiber length on the power consumption and refining efficiency were studied through the LC refining trials conducted by an experimental disc refiner. It is found that the curve of power-gap clearance can be divided into constant power section, power reduction section, and power increase section. And the no-load power and the adjustable domain of loading applied by the refining plates will increase as the increase of pulp consistency, while the increase of net power is larger than that of no-load power which makes the increasing of refining efficiency. Meanwhile, the adjustable domain of loading applied by the refining plates can be slightly improved by increasing the average fiber length, but its effect on the no-load power in the LC refining process can be neglected. The study of power consumption in LC refining is of positive significance for the proper selection of pulp properties in LC refining, in-depth exploration of refining mechanism, and energy consumption reduction in refining.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• 제24권9호
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• pp.706-715
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• 2014

Recently, the medical community has been enthusiastically welcoming robots that are able to provide high-quality medical services across the board, including assisting the surgeons during surgeries. In response, many higher education institutions and research facilities started to conduct various experiments and studies about these robots. During such research, it was discovered that the arm of one particular robot type that is being developed to assist surgeries are prone to vibrate even from the weakest impact, in addition to other residual vibration problems. We attempted to reduce such dynamic response by using a MF-TMD that is produced by adding magnetic fluid to ECD. We verified the MF-TMD's performance by testing it within various frequency bands and attenuations. We then designed a cantilever that was structurally similar to the robot's arm. We attached the MF-TMD to this cantilever and conducted a pilot experiment, which validated our hypothesis that MF-TMD will reduce the robot arm's vibrations through its optimal damping ratio. Henceforth, we attached the MF-TMD to the robot arm in question and conducted a performance experiment in which we tuned the MF-TMD's frequency and damping factor to its optimal level and measured the vibrations of the arm. The experiment demonstrated that the vibrations that occurred whenever the arms rotated were significantly reduced.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제16권12호
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• pp.2708-2715
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• 2012

This paper proposes a new sensorless speed control scheme of induction motor using Model Reference Adaptive Control and Direct Torque Control System. The Model Reference Adaptive Control System is based on the comparison between the outputs of Reference Model and Adjustable Model. The error between the estimated quantities obtained by the two models is used to drive a suitable adaptation mechanism which generates the estimated rotor speed for the Adjustable Model. And the Direct Torque Control scheme controls torque and flux by restricting the flux and torque errors within respective hysteresis bands, and motor torque and flux are controlled by the stator voltage space vector using optimum inverter switching table. The simulation results of proposed method indicate good speed responses from the low speed range to the high, and also show favorable characteristics of load operation.

• Journal of Power Electronics
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• 제3권2호
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• pp.99-114
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• 2003

This paper presents a feasible development on a highly accurate quick response adjustable speed drive implementation fur general purpose induction motor which operates on the basis of sensorless slip frequency type vector controlled sine-wave PWM inverter with an automatic tuning machine parameter estimation schemes. In the first place, the sensorless vector control theory on the three-phase voltage source-fed inverter induction motor drive system is developed in slip frequency based vector control principle. In particular, the essential procedure and considerations to measure and estimate the exact stator and rotor circuit parameters of general purpose induction motor are discussed under its operating conditions. The speed regulation characteristics of induction motor operated by the three-phase voltage-fed type current controlled PWM inverter using IGBT's is illustrated and evaluated fur machine parameter variations under the actual conditions of low frequency and high frequency operations for the load torque. In the second place, the variable speed induction motor drive system, employing sensorless vector control scheme which is based on three -phase high frequency carrier PWM inverter with automatic toning estimation schemes of the temperature -dependent and -independent machine circuit parameters, is practically implemented using DSP-based controller. Finally, the dynamic speed response performances for largely changed load torque disturbances as well as steady state speed vs. torque characteristics of this induction motor control implementation are illustrated and discussed from an experimental point of view.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 2부
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• pp.323-328
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• 2008

Inflatable Mouse is a volume-adjustable user interface. It can be inflated up to the volume of a familiar mouse, but be deflated and stored flat in a PC card slot of a laptop computer when not in use. Inflatable Mouse functions just like a typical mouse; moreover, it provides new interaction techniques by sensing the air pressure in the balloon of the mouse. It also addresses some issues associated with pressure-sensing interactions such as the lack of bi-directional control and the lack of effective feedback. Moreover, it can be used as both a control tool and a display tool. In this paper, the design of an Inflatable Mouse prototype is described and potential application scenarios such as zooming in/out and fast scrolling using pressure control are explained. We also discuss the potential use of Inflatable Mouse as an emotional communication tool.

• Transactions of the Korean Society of Mechanical Engineers A
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• 제41권5호
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• pp.427-433
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• 2017

In the case of high-strength or low thermal conductivity material milling, tool breakage occurs easily because of the high friction temperature. Therefore, the effectiveness of the coolant supply is very important for proper tool cooling. As the manually adjustable joint mechanism nozzle is generally used for coolant supply, the cooling efficiency is very low. It also has a bad influence on the workspace environment because of coolant scattering. In this study, the milling characteristics of STS316L were investigated according to the coolant spray position based on the automatic adjustable system. Tool wear and surface roughness were measured according to the coolant spray position. Through these experiments, the effectiveness of the fabricated system was explained.

• PNF and Movement
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• 제15권3호
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• pp.259-266
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• 2017

Purpose: This study aimed to compare muscle activities in the right leg during squatting on an angle-adjustable inclined wooden plate at three different angles. Methods: The subjects were 19 healthy adult men and women. An angle-adjustable inclined wooden plate was used for the experiment, and the subjects performed squatting at three adjusted angles of $0^{\circ}$ ankle angle, $10^{\circ}$ ankle flexion, and $10^{\circ}$ plantar flexion. Squatting was randomly performed without a sequence. The knee angle was set at $45^{\circ}$, and a goniometer was used to measure the angles accurately. Electromyography was employed to measure and compare muscle activity in the right leg in each condition. The measured data were converted to root mean square values to calculate the muscle activities. Results: This study showed no statistically significant difference at a $0^{\circ}$ ankle angle, but a statistically significant difference was found in the vastus medialis at $10^{\circ}$ of ankle flexion. Moreover, statistically significant differences were observed in the vastus medialis and lateralis at $10^{\circ}$ of plantar flexion. Conclusion: This study showed a statistically significant difference in the vastus medialis at $10^{\circ}$ of ankle flexion and statistically significant differences in the vastus medialis and lateralis at $10^{\circ}$ of plantar flexion. Therefore, it may be effective to perform squatting at $10^{\circ}$ of ankle flexion when intending to selectively strengthen the vastus medialis and at $10^{\circ}$ of plantar flexion when intending to strengthen both the vastus medialis and lateralis.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제17권7호
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• pp.1740-1746
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• 2013

Augmentative and alternative communication(AAC) is a communication tool for those with impairments or restrictions on the production or comprehension of spoken language. Traditional AAC has used a portable board with pictures and texts with which disabled person could be supported by it. Currently, smart phone based AAC researches and developments are actively studying. With emerging concepts of context-aware computing, the mobile devices can provide mobile users with timely information and location based services. We proposed a adjustable AAC system for disabled people of which has variable layouts and selectable items. We also implemented context-ware application for AAC systems including time, location and click count informations on smart phone. The system can adaptively change its layout and select AAC items depending on various situation of disabled persons.

• Archives of design research
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• 제12권1호
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• pp.157-166
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• 1999

With the increase in use of the computer, the VCT syndrome has occured as a new socialJhea/health problem. ErgonomicaI design standards are a for the users to reduce stress and poor physical posture in the human body. In this study. we have suggested design dimensions recommended from previous studies. We also have reviewed users' preference dimenision, and analyzed differences between users' preference dimenision. and the previous design aiteria to verify physical appropriateness. We analyzed how each design dimension was reached and affected the tunan body by objective EMG evaluation. and subjective evaluation of physical discomfort and oorrIort. We have found that keyboard height is very important in a workstation. If the elbow's height is lower than the keyboard's height. it effedS the hand and wrist. If higher, it brings fatigue to the shoulder and neck. As a result of this experiment. we suggested that the height of a keyboard desk for Koreans be 660mm for the fixed type and 540-774mm for the adjustable type. Also other design reoommendations were suggested in the thesis. In ooncIusion, our research will be very important in the database because it provides adjustable ranges to fit user's body types in the various design flekIs.

• The Journal of Advanced Prosthodontics
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• 제4권3호
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• pp.153-157
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• 2012

PURPOSE. The study was conducted to compare the radiographic and clinical methods of measuring the horizontal condylar guidance (HCG) values. MATERIALS AND METHODS. The condylar guidance was measured using the radiographic (CT scan) and three clinical methods i.e. the wax protrusive records, Lucia jig record and intraoral central bearing device in 12 patients aged between 20-40 years irrespective of sex. The records were taken and transferred on the semi-adjustable articulator to record the HCG values. The CT scan was taken for 3D reconstruction of the mid facial region. Frankfort horizontal plane (FHP) and a line extending from the superior anterior most point on the glenoid fossa to the most convex point on the apex of articular eminence (AE) was marked on the CT scan. An angle between these two lines was measured on both right and left sides to obtain condylar inclination angle. Three interocclusal protrusive wax and jig records were taken and transferred to the semi adjustable articulator. Three readings were recorded on each side. Similarly the records were taken and transferred to the same articulator using the intra oral central bearing device to record the readings. RESULTS. The statistical analysis showed insignificant differences in the HCG values between the right and left sides [(P=.589 (CT), P=.928 (wax), P=.625 (jig), P=.886 (tracer)]. The clinical methods provided low Pearsons correlation values [(R = 0.423 (wax), R = 0.354 (jig), R = 0.265 (tracer)] for the right as well as the left sides when compared with the CT values. Among the clinical methods, jig and wax method showed strong level of association which is statistically significant while the intra-oral tracer showed weak association with the other two methods. CONCLUSION. The right and left HCG values were almost similar. The CT scan showed higher HCG values than the clinical methods and among the clinical methods, values obtained from all the methods were comparable.