• Journal of Drive and Control
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• v.16 no.4
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• pp.48-55
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• 2019

The Electronic Stability Program (ESP), a system that improves vehicle safety, also known as YMC (Yaw Motion Controller) or VDC (Vehicle Dynamics Control), is a system that operates in unstable or sudden driving and braking situations. Developing conditions such as unstable or sudden driving and braking situations in a vehicle are very dangerous unless you are an experienced professional driver. Additionally, many repetitive tests are required to collect reliable data, and there are many variables to consider such as changes in the weather, road surface, and tire condition. To overcome this problem, in this paper, hardware and control software such as the ESP controller, vehicle engine, ABS, and TCS module, composed of three control zones, are modeled using MATLAB/SIMULINK, and the vehicle, climate, and road surface. Various environmental variables such as the driving course were modeled and studied for the real-time ESP real-time simulator that can be repeatedly tested under the same conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.501-509
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• 2010

A floating crane is a crane-mounted ship and is used to assemble or to transport heavy blocks in shipyards. In this paper, the static and dynamic response of a floating crane and a heavy block that are connected using elastic booms and wire ropes are described. The static and dynamic equations of surge, pitch, and heave for the system are derived on the basis of flexible multibody system dynamics. The equations of motion are fully coupled and highly nonlinear since they involve nonlinear mass matrices, elastic stiffness matrices, quadratic velocity vectors, and generalized external forces. A floating frame of reference and nodal coordinates are employed to model the boom as a flexible body. The nonlinear hydrostatic force, linear hydrodynamic force, wire-rope force, and mooring force are considered as the external forces. For numerical analysis, the Hilber-Hughes-Taylor method for implicit integration is used. The dynamic responses of the cargo are analyzed with respect to the results obtained by static and numerical analyses.

• Journal of the Korea Society of Computer and Information
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• v.14 no.2
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• pp.103-110
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• 2009

We are witnessing rapid increase of the number of wireless devices available today such as cell phones, PDAs, Wibro enabled devices. Because of the inherent limitation of the bandwidth available for wireless channels, broadcast systems have attracted the attention of the research community. The main problem in this area is to develop an efficient broadcast program. In this paper, we propose a dynamic broadcast method that overcomes the limitations of static broadcast programs. It optimizes the scheduling based on the probabilistic model of user requests. We show that dynamic broadcast system can indeed improve the quality of service using user requests. This paper extends our previous work in [1] to include more thorough explanation of the proposed methodology and diverse performance evaluation models.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.13 no.3
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• pp.237-245
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• 2008

We developed a computational method on coupled dynamics of tracked vehicle on seafloor and long flexible pipe. The tracked vehicle is modeled as rigid-body vehicle, and the linked flexible pipe is discretized according to a lumped-parameter model. The equations of motion of the rigid-body vehicle on the soft seafloor are combined with the governing equations of flexible pipe dynamics. Four Euler parameters method is used to express the orientations of the vehicle and the flexible pipe. In order to solve the nonlinear coupled dynamics of vehicle and flexible pipe an incremental-iterative formulation is implemented. For the time-domain integration $Newmark-\beta$ method is adopted. The total Jacobean matrix has been derived based on the incremental-iterative formulation. The interactions between the dynamics of flexible pipe and the mobility of the tracked vehicle on soft seafloor are investigated through numerical simulations in time domain.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.6
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• pp.36-42
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• 2009

In the mobile device environment, the context-aware computing has been emerging as a core technology of ubiquitous computing. Compared with a desktop computer, a user interface and resource of mobile device is very limited. Traditional desktop-based user interface has been developed on the basis that a user's activity is static state. In contrast, mobile devices are not able to utilize representative desktop-based interaction mechanisms such as a keyboard and mouse, not only because the activity of a user is dynamic state, but mobile devices have limited resources and small LCD display. In this paper, we introduce an intelligent control system for the mobile device that can utility effectively the limited resource and complement the poor user interface by using an accelerometer being able to sense the physical activity and posture. The proposed system can estimate the user activity, static and dynamic states, and posture watching the PDA at the same time, and the proposed intelligent control system as its application, the backlight ON/OFF on the PDA, is run by the result of the user's behavior.

• Journal of Advanced Navigation Technology
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• v.11 no.2
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• pp.209-216
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• 2007

In this paper, we embodied posture-stabilization and dynamic gait in a walking robot. 10 RC servo motors are used to operate joints. And the joints have enough moving ranges suitable in any walking pattern. Each joint trajectory is generated by cubic spline interpolation method and the stability of the trajectory is verified by using Zero Moment Point from the robot modeling. To avoid complex structure and expression, Zero Moment Point of the biped robot used angular acceleration is suggested. To measure the stability of the biped robot, Tilt sensor and gyro sensor are used. Finally, Personal Computer is used computer monitoring and data processing. Most of computation, such as 10 RC servo motor control, joint trajectory generating, ZMP compensation, sense measuring, etc, was used Digital Signal Processor.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.3
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• pp.254-260
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• 2011

Telemetry link is dynamic communication link that antenna gain and polarization are varying with the movement of the airplane. In this paper we calculated the antenna gain, polarization mismatch using the flight trajectory, motion of the airplane and 3D antenna pattern. And we modeled the multipath environment to the 2-Ray spherical earth reflection geometry, estimated the received signal strength when the narrow beam antenna received the RF signal transmitted from the airplane. Also we performed the flight test and after comparing measured value with the estimated value, we confirmed to almost coincide with each other.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.2
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• pp.159-165
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• 2013

Purpose: Abdominal compressor is used to control breathing in stereotactic body radiotherapy for lung tumors frequently. We evaluated the dynamic variation aspect of internal tumor volume by breathing. Materials and Methods: We reviewed 20 lung cancer patients (7 upper lung patients, 4 middle lung patients, 9 lower lung patients) who received stereotactic body radiotherapy using abdominal compressor between April 2012 to April 2013. Coordinate shift values were obtained by using four-dimensional cone-beam CT (4D-CBCT) to investigate treatment set-up error and moving tumor position error. To investigate how much difference of each part, we compared 95% confidence interval, maximum values and minimum values of three-dimensional vector value and analyzed conformity degree through the Pearson square correlation coefficient. Results: 95% confidence interval of three-dimensional vector value of each part is 1.8~2.9 mm in upper lobe, 2.3~5.4 mm in middle lobe and 2.2~4.0 mm in lower lobe. Conformity degree was the result that respectively is LR direction 0.75, SI direction 0.68 and AP direction 0.63 in upper lobe, LR direction 0.82, SI direction 0.51 and AP direction 0.92 in middle lobe and LR direction 0.63, SI direction 0.50 and AP direction 0.34 in lower lobe. Conclusion: We showed difference by each site in lung tumor due to respiration by using abdominal compressor. Therefore, we must correct treatment set-up error as well as moving tumor position error by breathing. It is also considered to be useful that it is the use of 4D-CBCT when correcting the error due to various dynamic variation.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.146-156
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• 2007

In this paper, the TVC actuation test and analysis results for a flexible seal kick motor nozzle are presented. A real-sized test model of KSLV-I kick motor system is applied to water pressurizing TVC tests which investigate the property changes in TVC nozzle expansion and TVC actuation performance against chamber pressure changes. The equipments which are required for TVC actuation tests are briefly explained. The TVC actuation tests are firstly accomplished in static mode, which reveals TVC error characteristics including thrust misalignment, control accuracy, and TVC stroke increase, etc. The properties in frequency domain is given via dynamic tests. These results may play an important role in enhancing the TVC control performance of KSLV-I.

• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.425-431
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• 2015

The objective of this study was to effect of Tai Chi on balance and muscle activity of ankle joints with USN sensor in elderly people. Thirty six elderly participated and randomly assigned to a experimental group with Tai Chi and control group. The experimental group trained using a Tai Chi through 3 times per a week over 6 weeks. For all subjects, their balance such as functional reach test and one leg stance test, the change of muscle activity of ankle joints with USN sensor wireless-electromyogram during leg closed stance with eye closed were measured, and the results were as followed. The results were of a signigicant changes to the balance in group and between group as well. Comparison of muscle activity left tibialis anterior and left gastrocnemius in group, there were significant difference. Comparison of muscle activity right tibialis anterior and right gastrocnemius in group, there were significant difference. Comparison of muscle activity between groups, there was significant difference. Additional results indicated that, elderly people who received Tai Chi in one study, improve balance control and muscle activity ankle joint. so it is anticipated that improvement in clinical utilization for the elderly who's gait ability and balance ability reduced.