• Information Systems Review
• /
• v.9 no.3
• /
• pp.99-132
• /
• 2007

As customer management rises by important issue in electronic commerce, virtue study about CRM have proceeded much. However, because existent researches were positive researches of most statistical base, There are some limitation that does not show dynamic change with CRM flow by flowing of time, and can not forecast propriety and future result about CRM strategy. Therefore, in order to overcome existent limitation on these CRM study, this study designed dynamic model which draws factors that compose CRM strategy of on-line shopping mall, and do based on technique in system dynamics so that can analyze dynamic change between these factors. Concretely, atomized customer focuses in the on-line shopping mall and does based on Permission marketing theory, and applied CRM of different level to atomized customers and know change of customer satisfaction measurement and discomfort degree accordingly. According to the result of Simulation practice, situation that achieve CRM strategy of different level by atomize customer more increase the customer satisfaction than situation that is not so. Dynamic pattern that presented in this study is expected that can verify validity about CRM achievement strategy of different level at each CRM point of contact & how Internet enterprise including on-line shopping mall is establishing CRM strategy reasonably.

• Journal of the Korea Society for Simulation
• /
• v.20 no.1
• /
• pp.79-85
• /
• 2011

The problem of evacuating pedestrians from a room or channel under panic conditions is of obvious importance in daily life. In recent years, several computer models have been developed to simulate pedestrian dynamics. Understanding evacuation dynamics can allow for the design of more comfortable and safe pedestrian facilities. However, these models do not take into account the type and state of mind of pedestrians. They deal with pedestrians as particles and the state of mind as a social force, which is represented by conservative and long-range interactions between individuals. In this study, I used the lattice model proposed in my previous study to explore the evacuation behavior of pedestrians with morality. In this model, three types of pedestrians are considered: adults, children, and injured people. Collisions between adults and children result in injured people. When the number of injured people continuously in contact with each other reaches a given value k, the injured people are removed from the lattice space. This situation is the same as that in which pedestrians start stepping over injured people. This behavior was interpreted as the morality of pedestrians. Simulations showed that the evacuation showed down and eventually became jammed owing to the injured people acting as "obstacles" in relation to the morality k.

• Journal of Korean Ophthalmic Optics Society
• /
• v.6 no.2
• /
• pp.85-97
• /
• 2001

A mathematical model was proposed to analyze the damped motion of contact lens which is initially displaced from the equilibrium position. The model incorporates the differential equations and their numerical solution program, based on the formulations of restoring force arising from the capillary action in the tear-film layer between the lens and cornea. The model predicts the capillary action induced surface tension, time dependence of displacement of lens when it is released from the equilibrium position. It seems that the motion of lens is similar to the typical over-damped oscillation caused by the large viscous friction in the liquid layer between the cornea and lens. The effect of variables such as base curves, lens diameters and thickness of tear film layer were illustrated by the computer simulation of the derived program. The time required for the lens to return to the original position increases as the liquid layer thickness increases and it decreases as the diameter of lens increases. With the certain value of base curve the time interval is found to be minimum. The free vibrations of lenses were also simulated varying the parameters such as base curve, diameter, layer thickness. The resonant frequencies are inversely proportional to the liquid layer thickness and it increases as the lens diameter increases. The resonant frequency of lens has a maximum when the diameter is of certain value. If the external impulse or force of the same frequency as the natural frequency of contact lens acted on the cornea in vivo it may cause an excessive movement and thus it might cause the distortion 10 the lens or be pulled off the eye.

• Transactions on Control, Automation and Systems Engineering
• /
• v.4 no.1
• /
• pp.100-107
• /
• 2002

The advanced bilateral control algorithm, which can enlarge a reflected force by combining force reflection and compliance control, greatly enhances workability in teleoperation. In this scheme the maximum boundaries of a compliance controller and a force reflection gain guaranteeing stability and good task performance greatly depend upon characteristics of a slave arm, a master arm, and an environment. These characteristics, however, are generally unknown in teleoperation. It is, therefore, very difficult to determine such maximum boundary of the gain. The paper presented a novel method for design of an advanced bilateral controller. The factors affecting task performance and stability in the advanced bilateral controller were analyzed and a design guideline was presented. The neurofuzzy compliance model (NFCM)-based bilateral control proposed herein is an algorithm designed to automatically determine the suitable compliance for a given task or environment. The NFCM, composed of a fuzzy logic controller (FLC) and a rule-learning mechanism, is used as a compliance controller. The FLC generates compliant motions according to contact forces. The rule-learning mechanism, which is based upon the reinforcement learning algorithm, trains the rule-base of the FLC until the given task is done successfully. Since the scheme allows the use of large force reflection gain, it can assure good task performance. Moreover, the scheme does not require any priori knowledge on a slave arm dynamics, a slave arm controller and an environment, and thus, it can be easily applied to the control of any telerobot systems. Through a series of experiments effectiveness of the proposed algorithm has been verified.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.32 no.4
• /
• pp.310-318
• /
• 2008

This paper presents a parallel typed walking robot to improve walking space and stability region. The robot is designed by inserting an intermediate mechanism between upper leg mechanism and lower leg mechanism. The leg mechanism is composed of three legs and base, which form a parallel mechanism with ground. Seven different types of walking robot are invented by combining the leg mechanisms and an intermediate mechanism. Topology is applied to design the leg mechanism. A motor vector is adopted to determine Jacobian and a wrench vector is used to analyze dynamics of the robot. We explore the stability region of the robot from the reaction force of legs and compute ZMP including the holding force to contact the foot to a wall. This investigates a walking stability when the robot walks on the ground as well as on the wall. We examine the walking space generated by support legs and by swing legs. The robot has both a large positional walking space and a large orientational walking space so that it can climb from a floor up to a wall.

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.859-864
• /
• 2003

This paper presents a design for the novel suspension mechanism of a two-wheeled mobile robot having two casters which is used for indoor environment. Although the indoor environment is less rough than the outdoor one, the fixed caster mechanism has some problems such as causing the robot to be immovable because robot's driving wheels do not have contact with the ground. Therefore, we tried installing a spring-damper suspension mechanism to keep driving capability and to remove pitching phenomenon. However, this suspension mechanism also has the problem, which the robot body inclined by disturbances does not return to the initial position. To deal with above problems and to accomplish desired performances, we designed the Multilayered Suspension Mechanism, which has springs and dampers working partially according to the inclined angle and angular velocity of robot body concerned with pitching. To analyze design, the equations of motion describing their dynamics were developed. Using the equations, simulation results show the improved performance. We confirm the usefulness of the Multilayered Suspension Mechanism by construction and test of a actual prototype.

• International Journal of Fluid Machinery and Systems
• /
• v.3 no.2
• /
• pp.102-112
• /
• 2010

Artificial heart pumps have attracted the attention of researchers around the world as an alternative to the organ used in cardiac transplantation. Conventional centrifugal pumps are no longer considered suitable for long-term application because of the possibility of occurrence of blood leakage and thrombus formation around the shaft seal. To overcome this problem posed by the shaft seal in conventional centrifugal pumps, the magnetically suspended centrifugal pump has been developed; this is a sealless rotor pump, which can provide contact-free rotation of the impeller without leading to material wear. In Europe, clinical trials of this pump have been successfully performed, and these pumps are commercially available. One of the aims of our study is to numerically examine the internal flow and the effect of leakage flow through the gap between the impeller and the pump casing on the performance of the pump. The results show that the pressure head increases compared with the pump without a gap for all flow rates because of the leakage of the fluid through the gap. It was observed that the leakage flow rate in the pump is sufficiently large; further, no stagnant fluid or dead flow regions were observed in the pump. Therefore, the present pump can efficiently enhance the washout effect.

• BMB Reports
• /
• v.51 no.9
• /
• pp.425-426
• /
• 2018

As highly conserved signaling cascades of multicellular organisms, Wnt and Hippo pathways control a wide range of cellular activities, including cell adhesion, fate determination, cell cycle, motility, polarity, and metabolism. Dysregulation of those pathways are implicated in many human diseases, including cancer. Similarly to ${\beta}-catenin$ in the Wnt pathway, the YAP transcription co-activator is a major player in Hippo. Although the intracellular dynamics of YAP are well-known to largely depend on phosphorylation by LATS and AMPK kinases, the molecular effector of YAP cytosolic translocation remains unidentified. Recently, we reported that the Dishevelled (DVL), a key scaffolding protein between canonical and non-canonical Wnt pathway, is responsible for nuclear export of phosphorylated YAP. The DVL is also required for YAP intracellular trafficking induced by E-cadherin, ${\alpha}-catenin$, or metabolic stress. Note that the p53/LATS2 and LKB1/AMPK tumor suppressor axes, commonly inactivated in human cancer, govern the reciprocal inhibition between DVL and YAP. Conversely, loss of the tumor suppressor allows co-activation of YAP and Wnt independent of epithelial polarity or contact inhibition in human cancer. These observations provide novel mechanistic insight into (1) a tight molecular connection merging the Wnt and Hippo pathways, and (2) the importance of tumor suppressor contexts with respect to controlled proliferation and epithelial polarity regulated by cell adhesion.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1060-1067
• /
• 2005

This paper attempts to derive and analyze the dynamic system of pinching a rigid object by means of two multi-degrees-of-freedom robot fingers with soft and deformable tips. It is shown firstly that a set of differential equation describing dynamics system of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. It is shown secondly that the problems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. In this paper, the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation that the control system gives the performance improvement in the dynamic stable grasping of the dual fingers robot with soft tips.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.6 s.177
• /
• pp.1633-1642
• /
• 2000

Like many other mechanical dynamic systems, flexible manipulator systems experience stiction or sticking friction, which may cause input-dependent instabilities. Manipulator performance can be enha nced by identifying friction but it is hard and expensive to measure friction by direct and precise sensing of contact displacements and forces. This study addresses the problem of identifying flexible manipulator joint friction. A dynamic model of a two-link flexible manipulator based upon finite element and Lagrange's method is constructed. The dynamic model includes the effects of joint compliances and actuator dynamics. Friction is also incorporated in the dynamic model to account for stick-slip at the joints. Next, the friction parameters are to be determined. The identification problem is posed as an optimization problem to be solved using nonlinear programming methods. A genetic algorithm is used to increase the convergence rate and the chances of finding the global optimum. The identified friction parameters are experimentally verified and it is expected that the identification technique is applicable to a system parameter identification problem associated with a wide class of nonlinear systems.