• Proceedings of the Korean Society for Bioinformatics Conference
• /
• 2005.09a
• /
• pp.278-283
• /
• 2005

Cell cycle is regulated cooperatively by several genes. The dynamic regulatory mechanism of protein interaction network of cell cycle will be presented taking the budding yeast as a sample system. Based on the mathematical model developed by Chen et at. (MBC, 11,369), at first, the dynamic role of the feedback loops is investigated. Secondly, using a bifurcation diagram, dynamic analysis of the cell cycle regulation is illustrated. The bifurcation diagram is a kind of ‘dynamic road map’ with stable and unstable solutions. On the map, a stable solution denotes a ‘road’ attracting the state and an unstable solution ‘a repelling road’ The ‘START’ transition, the initiation of the cell cycle, occurs at the point where the dynamic road changes from a fixed point to an oscillatory solution. The 'FINISH' transition, the completion of a cell cycle, is returning back to the initial state. The bifurcation analysis for the mutants could be used uncovering the role of proteins in the cell cycle regulation network.

• Korean System Dynamics Review
• /
• v.11 no.2
• /
• pp.77-102
• /
• 2010

This paper examines a mechanism of the Electronic Territory Expansion and the Information-oriented Society. Especially, a strategy for the territory development based on intelligence is suggested. The strategy is divided into a strategy for the domestic electronic territory and a plan for the global electronic territory. To examine the strategy and the plan, this paper is using the causal map analysis based on the System Thinking Approach. The causal map of the mechanism is characterized by a positive feedback loop. The paper has concluded that it is important to make the positive loops as a virtuous circle. It means that when a society dominates the advantageous position firstly in the field of intelligent and electronic territory, the competitiveness can grow in arithmetical progression.

• Journal of Power Electronics
• /
• v.16 no.4
• /
• pp.1587-1597
• /
• 2016

A novel active damping strategy for the LCL filter resonance is proposed using the grid current and the capacitor voltage. The proposed technique is deduced in the continuous time domain and a discussion for its discrete implementation is presented. According to the proposed technique, instability of the open loop system, which results in non-minimum phase behavior, can be avoided over wide range of resonant frequencies. Moreover, straightforward co-design steps for both the fundamental current regulator and the active damping loops can be used. A numerical example along with experimental results are introduced to validate the proposed strategy performance over wide range of resonant frequencies.

• Korean System Dynamics Review
• /
• v.16 no.4
• /
• pp.103-128
• /
• 2015

This study investigated dynamic causal relationship between CSR implementation and consumption of environmentally friendly fashion products through systems thinking. Based on literature review and empirical research, we drew causal loop diagram for CSR implementation in environmentally friendly fashion product industry. By analyzing feedback loops, we found that companies and consumers interact in the process of CSR activities. In the process of CSR implementation, companies and consumers are closely related and affect each other as stimuli and prior condition. This study suggests that companies adopt push strategy to actively create demand by developing and promoting environmentally friendly fashion products and that companies communicate with consumers in order to be recognized and rewarded by consumers for their CSR activities. In addition, this study suggests that consumers not only support companies of CSR activities but also actively boycott anti-environmental companies by collective action.

• Journal of the Korean Society for Aviation and Aeronautics
• /
• v.23 no.2
• /
• pp.63-68
• /
• 2015

This paper presents the algorithm for envelope protection of helicopters. The algorithm consists of two feedback control loops: inner loop and outer loop. As an inner loop control, model following control is designed to meet the ADS-33 handling qualities specification by minimizing the tracking errors between the responses of the actual model and those of the command filter. In order to implement envelope protection, saturation limiter is imposed to command channels in command filter, whose limits are computed corresponding to the envelope limit. Fast model predictive control is designed as an outer loop control to deal with saturation constraints generated by the inner loop envelope protection and also imposed by outer loop envelope protection variables. Simulation results show that the proposed algorithm yields good envelope protection performance.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.245-247
• /
• 1992

We utilize as a processor TMS320C25 (Texas Instrument) in making a driver for a 4 pole PM synchronous servo motor. TMS320C25 has a 32bit ALU and a 16 bit hardware multiplier, and the maximum instruction execution rate is 10MIPS at 40MHz. We adopted a space vector modulation PWM method. An interesting point of this work is that PWM wave is generated by utilizing timer interrupts. Hence, in the rest of time the processor can take care of the other routine such as Park's coordinate transformation and the computation required in the feedback loops. Thus, it mates the hardware circuit very simple. Due to the decrease in the number of components, the motor drive system becomes more fault-tolerant and cost-optimized. Also, more flexibility is gained in changing the control parameters.

• Journal of the Korean Society for Precision Engineering
• /
• v.5 no.2
• /
• pp.23-32
• /
• 1988

A control system for improving the moving accuracy of robotic manipulators with elastic joints is devloped. The dynamics of manipulator system is splitted into two sub-dynamics; of arm-link and actuator rotor- link, which are coupled statically through joint torque. Two contorl loops are implemented respectively around both sub-dynamic systems. Computed torque algorithm with acceleration feedback is used for the arm-link control loop, and for the actuator rotor-link control loop PID algorithm is adopted. The resulting control system is tested through a series of computer simulation for a PUMA type manipulator, The reaults show good performance of the developed control system for wide range of joint stiffness and moving speed.

• Korean System Dynamics Review
• /
• v.13 no.4
• /
• pp.5-31
• /
• 2012

This paper aims at investigating the dynamics between aging population and local finance. In recent years, the aging rate has been accelerating the pace. The trend implies that Korea is moving towards the aging society, presumably, with unprecedented speed in the world. Aging society's biggest problems are centered around the explosive growth of the financial needs. In particular, these problems are apt to appear more seriously in local governments, as most of them are confronted with high level of aging population and poor financial bases. Firstly, it analyzes how the population structure in the local government impacts local finance, income and expenditure. Based upon in-depth literature reviews, this study examines variables related to aging population and local fiance. Secondly, it focuses on a series of positive and negative feedback loops which would reveal the essence of the mutual interaction structure between aging population and local governments' fiscal behaviors.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.736-741
• /
• 1998

It is well known that an encoder or a resolver is necessary to obtain the position data for speed or position control Generally utilized speed sensors are mal-affected by the EMI, dusty, and high temperature surroundings. Therefore, the speed and position sensorless controls using observers have been studied widely. In this paper, the binary observer which is composed of two feedback regulation loops to control the speed of SRM(Switched Reluctance Motor) is applied. One loop compensates the control input directly like the sliding mode control, and the other one compensates the system parameters indirectly. This observer is constructed on the foundation of variable structure control on the foundation of variable structure control theory and has the inertial term for the varying parameter. The validities of this proposed method is proved by experiments.

• Proceedings of the KIPE Conference
• /
• 2002.07a
• /
• pp.763-768
• /
• 2002

In this paper digitally based excitation systems for the synchronous brushless generators are presented. System configuration, control functions with their structure functions are also shown. The control system has two feedback loops: main one based on a generator's voltage with digital controller and inner one based on excitation voltage of the exciter with analog controller. Usually the generator regulation of voltage Is made with transducers for the voltage measurement. This paper shows technique of measuring the voltage without harmonics affect, using Park's equation transformation.