• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.2
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• pp.9-18
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• 2014

This paper proposes the fuzzy PI controller for maximum power point tracking(MPPT) control of photovoltaic system. The output characteristics of the solar cell are a nonlinear and affected by a temperature, the solar radiation. The MPPT control is a very important technique in order to increase an output and efficiency of the photovoltaic system. The conventional perturbation and observation(PO) and incremental conductance(IC) are the method which finding maximum power point(MPP) by the continued self-excitation vibration, and uses the fixed step size. If the fixed step size is a large, the tracking speed of maximum power point is faster, but the tracking accuracy in the steady state is decreased. On the contrary, when the fixed step size is a small, the tracking accuracy is increased and the tracking speed is slower. Therefore, this paper proposes the MPPT control using the fuzzy PI controller that can be improve a MPPT control performance. The fuzzy PI controller is adjusted a input of PI controller by fuzzy control and compensated a cumulative error of fuzzy control by PI controller. The fuzzy PI MPPT control is compared to conventional PO and IC MPPT method for various temperature and radiation condition. This paper proves the validity of the fuzzy PI controller using these results.

• Journal of the Korean Solar Energy Society
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• v.32 no.4
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• pp.96-102
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• 2012

The minimum airflow of VAV terminal boxes is a key factor for comfort, indoor air quality(IAQ) and energy cost. If the minimum airflow is not reasonable, it would waste energy and make IAQ problems. There are two types of VAV terminal box control logic. One is the single maximum, another is the dual maximum control logic. Dual maximum control logic is more efficiency way to reduce the energy consumption. It has a minimum airflow set point and a heating maximum set point. It allows the minimum airflow set point to be much lower than single maximum control logic. A building simulation was conducted to evaluate the energy consumption and the IAQ according to the control logic of the V AV terminal box. In the simulation, dual maximum control logic can save the energy up to 6.5% compared to the single maximum control logic.

• Honam Mathematical Journal
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• v.38 no.2
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• pp.337-357
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• 2016

The notion of weak contraction in intuitionistic fuzzy metric space is well known and its study is well entrenched in the literature. This paper introduces the notion of (${\psi},{\alpha},{\beta}$)-weak contraction in intuitionistic fuzzy metric space. In this contrast, we prove certain coincidence point results in partially ordered intuitionistic fuzzy metric spaces for functions which satisfy a certain inequality involving three control functions. In the course of investigation, we found that by imposing some additional conditions on the mappings, coincidence point turns out to be a fixed point. Moreover, we establish a theorem as an application of our results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.220-223
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• 2021

This paper concerns a flow control method that can reduce rainwater containing non-point contamination accumulated on road surfaces during initial rainfall. In early rainfall, non-point pollutants are blocked from entering rivers and oceans and flow to sewage treatment plants. Afterwards, rainwater, which has been removed from the non-point pollution source through jet lag, is safely flowing into the river.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.577-582
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• 1989

This is a study of the translational end-point control of a single link flexible arm-with a tip mass. The beam is mounted on a translational mechanism driven by the ball screw, whose rotation is controlled by DC servomotor. The problem of shifting the end-point from its initial position to the commanded position is studied analytically both for the open-loop control subjected to some path functions and for the closed-loop control using the feedback of the tip information.

• Journal of Industrial Technology
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• v.21 no.B
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• pp.117-123
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• 2001

In a modern control field, a control engineer who has theoretical backgrounds with some practical knowledge is demanded. That is to say, an engineer who can understand and operate the various parts such as modeling, simulation, system analysis, signal processing, statistics, and hardware is required. In order to prove the theoretical backgrounds and operate various hardwares, a lot of experimental devices for students are designed in universities. Since the conventional experimental devices are manufactured abroad and the prices of the devices are too high, it is difficult to have. If a low cost experimental device can be developed, it will be very useful for a control engineering education. In Ibis paper, an experimental rig which has two control inputs and three sensor outputs to control the end point of a flexible beam is designed and manufactured. This rig can be used for a control field education.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.74-82
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• 2013

This paper presents a novel maximum power point tracking for a photovoltaic power (PV) system with a direct control plan. Maximum power point tracking (MPPT) must usually be integrated with photovoltaic (PV) power systems so that the photovoltaic arrays are able to deliver maximum available power. The maximum available power is tracked using specialized algorithms such as Perturb and Observe (P&O) and incremental Conductance (indCond) methods. The proposed method has the direct control of the MPPT algorithm to change the duty cycle of a dc-dc converter. The main difference of the proposed system to existing MPPT systems includes elimination of the proportional-integral control loop and investigation of the effect of simplifying the control circuit. The proposed method thus has not only faster dynamic performance but also high tracking accuracy. Without a conventional controller, this method can control the dc-dc converter. A simulation model and the direct control of MPPT algorithm for the PV power system are developed by Matlab/Simulink, SimPowerSystems and Matlab/Stateflow.

• Korean Journal of Adult Nursing
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• v.21 no.6
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• pp.628-638
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• 2009

Purpose: This study was to develop a nursing education program for mothers with a young child undergoing cardiac surgery and determine effects of the program on her knowledge, anxiety and coping behavior. Methods: The research design was a nonequivalent control group non-synchronized design. 18 mothers were assigned to the experimental group and 18 to the control group. The effects were evaluated by measuring knowledge, anxiety, and coping behavior. The collected data was analyzed through independent t-test, and repeated measures ANOVA respectively using SPSS/WIN 12.0 program. Results: The point of knowledge in the experimental group was significantly increased tan that in the control group. The point of subjective, physiological, and behavior anxiety in the experimental group was significantly decreased than that in the control group by time change. The point of coping behavior in the experimental group was significantly higher than that in the control group. Conclusion: The nursing educational program for a young child with cardiac surgery is expected to be clinically applied as an intervention program for mothers with a young child undergoing cardiac surgery.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.137-143
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• 2017

In this paper, we investigate static control of Boolean networks described in the framework of semi-tensor product (STP) operation. The control objective is to determine control input nodes and their logical values so as to stabilize the considered Boolean network to a desired fixed point or cycle. Using topology of Boolean networks such as incidence matrix and hub nodes, a set of appropriate control input nodes is selected, and based on STP operations, we assign constant control inputs so that the controlled network can converge to a prescribed fixed point or cycle. To validate applicability of the proposed scheme, we conduct a numerical study on the problem of determining control input nodes for a Boolean network representing hierarchical differentiation of myeloid progenitors.

• Journal of Advanced Information Technology and Convergence
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• v.9 no.1
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• pp.11-24
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• 2019

This paper investigates the performance comparison of a Terahertz (THz) communications for a single-carrier and a multi-carrier single antenna point-to-point communication system. The multi-carrier system and single carrier system consider the orthogonal frequency division multiplexing (OFDM) and the minimum mean square error linear equalizer (MMSE-LE), respectively. We compare the frame-error-rate (FER) and throughput performance of both the systems for a THz communication environment with the carrier frequency of 300GHz and the tapped delay line (TDL) channel models described in 3GPP. It is observed from the simulation results that the OFDM systems outperform the MMSE-LE for various configurations.