• Journal of the Korean Society for Precision Engineering
• /
• v.13 no.7
• /
• pp.90-99
• /
• 1996

In the area of assembly process of micro-chips and electronic parts on the printed circuit board, surface mounting device(SMD) is used as a fundamental tool. Generally speaking, the motion of the SMD is based on the ball screw system operated by any type of actuators. The ball screw system is a mechanical transformed which converts the mechanical rotational motion to the translational one. Also, this system could be considered as an efficient motion device against mechanical backlash and friction. Therefore a dynamic modeling and state sensitivity analysis of the ball screw system in SMD have to be done in the initial design stage. In this paper, a simple mathematical dynamic model for this system and the sensit- ivity analysis are mentioned. Especially, the bond graph approach is used for graphical modeling of the dynamic system before analysis stage. And the direct differentiation method is used for the state sensit- ivity analysis of the system. Finally, some trends for the state variables with respect to the design variables could be suggested for the better design and faster operating based on the results of dynamic and state sensitivity.

• Child Health Nursing Research
• /
• v.7 no.3
• /
• pp.298-307
• /
• 2001

This study assessed behavioral characteristics of 73 normal neonates in Daegu area using the NBAS. Being one of few studies on this topic, the study is to document and to accumulate data on the neonatal behaviors of Korean babies. Overall scores were at moderate levels in 6 behavioral clusters including Habituation, Social Interactive, Motor System, State Organization, and State Regulation. Autonomic Stability showed relative stableness. Scores of Orientation were higher in neonates of working mothers and rural mothers. Neonates of mothers with no abortion history have higher scores in Motor System and State Organization. Score of State Organization was higher in neonates of mothers with no habitual use of amenity during their pregnancy. Scores of Habituation and State Organization, as well as scores of Motor System with State Organization, State Regulation and Autonomic Stability were positively correlated. Scores of Habituation and State Organization indicate that babies are agreeable and even tameable that is advantageous for attachment to caregiver.

• Journal of the Korean Society of Systems Engineering
• /
• v.14 no.1
• /
• pp.36-43
• /
• 2018

The availability of the weapon system can be analyzed through state modeling and simulation using the Markov process. In this paper, show how to analyze the availability of the weapon system and can use the Markov process to analyze the system's steady state as well as the RAM at a transient state in time. As a result of the availability analysis of tracked vehicles, the inherent availability was 2.6% and the operational availability was 1.2% The validity criterion was defined as the case where the difference was within 3%, and thus it was judged to be valid. We have identified the faulty items through graphs of the number of visits per state among the results obtained through the MPS and can use them to provide design alternatives.

• Proceedings of the KSPS conference
• /
• 2007.05a
• /
• pp.29-32
• /
• 2007

This paper describes a multimodal dialog system that uses Hidden Information State (HIS) method to manage the human-machine dialog. HIS dialog manager is a variation of classic partially observable Markov decision process (POMDP), which provides one of the stochastic dialog modeling frameworks. Because dialog modeling using conventional POMDP requires very large size of state space, it has been hard to apply POMDP to the real domain of dialog system. In HIS dialog manager, system groups the belief states to reduce the size of state space, so that HIS dialog manager can be used in real world domain of dialog system. We adapted this HIS method to Smart-home domain multimodal dialog system.

• 제어로봇시스템학회:학술대회논문집
• /
• 1995.10a
• /
• pp.468-471
• /
• 1995

In this paper, we propose a new strategy for a space robot to control its attitude. A space robot is an example of a class of non-holonomic systems, a system of which cannot be stabilized into its equilibria with continuous static state feedbacks even in the case that the system is, in some sense, controllable. Thus, we cannot design stabilizing controllers for space robots using conventional control theories. The strategy presented here transforms the non-holonomic system into a time-state control form, and allows us to make the state of the original system any desired one. In the stabilization, any conventional control theory can be applied. For simplicity, a space robot with a two-link manipulator is considered, and a simulated motion of the controlled system is shown.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.26 no.12
• /
• pp.579-587
• /
• 2014

This paper deals with precise analytical state equation modeling of a variable speed refrigeration system (VSRS) for optimum control in state space. The VSRS is described as multi-input and multi-output (MIMO) system, which has two controlled variables and two control inputs. First, the Navier-Stokes equation and mass flow rate were applied to each component of the basic refrigeration cycle to build a dynamic model. The dynamic model, represented by a differential equation, was transformed into the state equation formula. Next, a full-order state observer was built to estimate all of the state variables to compose an optimum control system. Then, an optimum controller was designed to minimize an evaluation function that has input energy and control error. Finally, simulations and experiments were conducted to verify the validity of the proposed modeling and designed optimum controller to regulate target temperature and superheat in a 1RT oil cooler system. The results show that the proposed method, state equation modeling and optimum control, is efficient to ensure optimal control performance of the VSRS.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.12
• /
• pp.1183-1187
• /
• 2011

In this paper, an optimal FIR (Finite-Impulse-Response) filter is proposed for discrete time-varying state-space models. The proposed filter estimates the current state using measured output samples on the recent time horizon so that the variance of the estimation error is minimized. It is designed to be linear, unbiased, with an FIR structure, and is independent of any state information. Due to its FIR structure, the proposed filter is believed to be robust for modeling uncertainty or numerical errors than other IIR filters, such as the Kalman filter. For a general system with system and measurement noise, the proposed filter is derived without any artificial assumptions such as the nonsingular assumption of the system matrix A and any infinite covariance of the initial state. A numerical example show that the proposed FIR filter has better performance than the Kalman filter based on the IIR (Infinite- Impulse-Response) structure when modeling uncertainties exist.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.26 no.1
• /
• pp.38-43
• /
• 2012

For safe and stable operations of power plants, it is essential to monitor closely crucial measurement values related to power plant trips. In this paper, an intelligent power plant operating state monitoring technique enabling the operating crew member to monitor conveniently the status of the important measurement values and to perceive almost instantly the significance of the implications of those measurement values is developed. The proposed technique is called a "POST(Plant Operating State Tracking) Chart" technique and provides the foundations in developing an intelligent and integrated power plant operating state monitoring support system called the "P-OASIS"(Plant Operation Assessment and Support Intelligent System). The P-OASIS is applied to a thermal power plant of 500[MW] capacity and exhibited impressive performances.

• International Journal of Reliability and Applications
• /
• v.11 no.2
• /
• pp.69-87
• /
• 2010

The optimal replacement problem was investigated for a multi-state deteriorated system for which the true internal state cannot be observed directly except when the system breaks down completely. The internal state was assumed to be monitored incompletely by a monitor that gives information related to the true state of the system. The problem was formulated as a partially observable Markov decision process. The optimal procedure was found to be a monotone procedure with respect to stochastic increasing ordering of the state probability vectors under some assumptions. Limiting the optimal procedure to a monotone procedure would greatly reduce the tremendous amount of calculation time required to find the optimal procedure.

• Journal of Agricultural Extension & Community Development
• /
• v.10 no.2
• /
• pp.211-227
• /
• 2003

According to the TRQ system created by WTO agreement on agriculture, Korea notified the WTO of the application of tariff rate quotas for 67 agricultural commodities(now, 63 commodities). Among these government administrate state-operated trade for 17 commodities. However, WTO/DDA negotiation will bring about lowering tariffs and increasing quantities of tariff quota. This study suggest the development programs corresponding WTO/DDA agriculture negotiation. First, from the viewpoint of the protection of domestic agriculture & improving transparency of agricultural import administration, the administration system of the state-operated trade will be necessary to be transformed for market oriented methods. Second, the administration system of the state-operated trade will be necessary to be rendered unified organization also. The current system of the state-operated trade shows the phenomena og many divergency. And third, The quantities of market access of FTA between Korea and Chile will be desirable to be administrate by state-operated trade. Because, according to diffusion of FTA treaties, the amount of market access quantities of FTA increase rapidly henceforth.