• Journal of Auto-vehicle Safety Association
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• v.5 no.1
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• pp.31-36
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• 2013

For the robust passenger NCAP 5star and the stable neck injury performance, a new concept of passenger airbag has been required strongly. Especially, the deployment stability and the vent hole control technology of the passenger airbag should be improved. According to these requirements, the deployment stability technique has been studied and the 'Active Vent' technology has been developed. As a result, these technologies have led to achieve the robust NCAP rating and are applied to the production vehicles.

• Journal of the Korean Statistical Society
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• v.32 no.4
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• pp.337-357
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• 2003

This paper introduces new measures for the stability of slope estimation on the second order response surface at a point and on a sphere. As a measure of point stability of slope estimation, we suggest a point dispersion measure of slope variances over all directions at a point. A spherical dispersion measure is also proposed as a measure of spherical stability of slope estimation on each sphere. Some designs are studied to explore the usefulness of the proposed measures. Using the point dispersion measure, another concept of slope rotatability called equally-stable slope rotatability is proposed as a useful property of response surface designs. We provide a set of conditions for a design to have equally-stable slope rotatability.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1664-1670
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• 1991

For kinematically redundant manipulators, conventional dynamic control methods of local torque optimization showed the instability which resulted in physically unachievable torque requirements. In order to guarantee stability of the null space vector method which resolves redundancy at the acceleration level, Maciejewski[1] analyzed the kinetic behavior of homogeneous solution component and proposed the condition to identify regions of stability and instability for this method. 'In this paper, a modified null space vector method is first presented based on the Maciejewski's condition which is a function of a manipulator's configuration. Secondly, a new control method which is based on the concept of aspects is proposed. It was shown by computer simulations that the modified null space vector method and the proposed method have a common property that a preferred aspect is preserved during the execution of a task. It was also illustrated that both methods demonstrate a drastic reduction of torque loadings at the joints in the tracking motion of a long trajectory when compared with the null space vector method, and thus guarantee the stability of joint torque.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1131-1139
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• 2004

A new impedance controller is proposed for bilateral teleoperation under a time delay. The proposed controller does not need to measure or estimate the time delay in the communication channel using the force loop-back. In designing a stable impedance controller, absolute stability is used as a stability analysis tool, which results in a less conservative controller than the passivity concept. Moreover, in order to remove the conservatism associated with the assumption of infinite port impedances, the boundaries of human and environment impedance are set to finite values. Based on this, this paper proposes a parameter design procedure for stable impedance controllers. The validity of the proposed control scheme is demonstrated by experiments with a 1-dof master/slave system.

• The Journal of Korean Physical Therapy
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• v.16 no.4
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• pp.11-22
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• 2004

The concept of segmental stabilization has been one of the most exciting advancements in the field of physical therapy. Specific deep stabilizing muscle have proven to reverse motor control deficits that occurs after back injury. After an injury, a new motor programming strategy is adopted and there is excessive recruitment of the large , strong , global muscular system works instead of small segmental deep muscle recruitment for stability. Many physical therapists and doctors mistakenly prescribe therapeutic exercise for low back pain to use larger, superficial musculature to strengthen the spine for stability and pain control. But motor control coordination of local segmental muscle is actually the key to stability and pain control, not strengthening of global muscle. A recent focus in physiotherapy management of patients with chronic back pain has been the specific training of muscles surrounding the lumbar spine whose primary role is considered to be the provision of dynamic stability and segmental control to the spine. These are the deep transverse abdominis muscle and lumbar multifudus.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.407-412
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• 1998

In this work, a new time integration method is proposed using the generalized derivative concept to simulate the dynamic phenomena having sudden constraint occurring in dynamic contact/impact problems. By the adoption of the generalized derivative concept and jump assumption, discontinuity can be incorporated in time integration and as a result, the algorithm does not need any other special consideration of jumps in dynamic field variables due to sudden constraint like dynamic contact-release conditions. To observe the characteristics of the proposed time integration method, the stability and convergence analyses are carried out. In numerical tests, several dynamic contact/impact problems are analyzed by straightforward application of the proposed time integration method with the exterior penalty method.

• Journal of the Korea Society for Simulation
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• v.10 no.2
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• pp.33-46
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• 2001

Recently, the usage of containers in marine transportation is rapidly increasing. The problem of ship stability is important because of its direct influence to the loss of the human-life, ship, and merchandise. However, the assessment for ship stability during container loading/unloading in port is dependent on human experience only. On the other hand, the emerging information and communication technologies of shipbuilding industrial environments are rapidly changing. To respond to the situation, a new paradigm has been matured with new concepts such as the concrete method. Especially, all the efforts are shown to be concentrated to realize the concept of Simulation Based Design(SBD) based on three dimensional Computer Aided Design(CAD) model. In this paper, ship model-based simulation methodology for design and operation of ship is suggested, and for the verification of suggested methodology, the system for stability assessment of ship during container loading/unloading was developed using ENVISION, a general-purpose simulation system. The developed system consists of geometric modeling subsystem, basic calculation subsystem, and Computer Aided Engineering(CAE) subsystem. In addition, interface to CAE/CAD /simulation system such as SIKOB and ENVISION is provided.

• Wind and Structures
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• v.20 no.1
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• pp.95-115
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• 2015

Wind effects on roofs are usually considered by equivalent static wind loads based on the equivalence of displacement or internal force for structural design. However, for large-span spatial structures that are prone to dynamic instability under strong winds, such equivalent static wind loads may be inapplicable. The dynamic stability of spatial structures under unsteady wind forces is therefore studied in this paper. A new concept and its corresponding method for dynamic instability-aimed equivalent static wind loads are proposed for structural engineers. The method is applied in the dynamic stability design of an actual double-layer cylindrical reticulated shell under wind actions. An experimental-numerical method is adopted to study the dynamic stability of the shell and the dynamic instability originating from critical wind velocity. The dynamic instability-aimed equivalent static wind loads of the shell are obtained.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.864-869
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• 2004

A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed -loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. It is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. Ill this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.10
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• pp.955-961
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• 2004

A novel concept of feedback loop design for modal test and model updating is proposed. This method uses the closed-loop natural frequency information for parameter modification to overcome the problems associated with the conventional method employing the modal sensitivity matrix. To obtain new modal information from closed-loop system, controllers should be effective in changing modal data while guaranteeing the stability of closed-loop system. But it is very hard to guarantee the stability of the closed-loop system with non-collocated sensor and actuator set. In this research, we proposed a controller called mode-decoupling controller that can change a target mode as much as the designer wants guaranteeing the stability of closed-loop system. This controller can be computed Just using measured open-loop modeshape matrix. A simulation based on time domain input/output data is performed to check the feasibility of proposed control method.