• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.533-534
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• 2006

Micro-source units having power ratings in thousands of watts can provide power quality with higher reliability and efficiency than the conventional large scale units. This paper develops switching level model of micro-source and studies the characteristics of the micro-grid consisting of multiple micro-sources and interfaced with electric power system. The developed model adopts the space vector PWM to fully utilize the capacity of inverter. The interaction of the grid connected micro-sources and the characteristics of the control system parameters are investigated. Micro-sources and micro-grid are implemented using PSCAD/EMTDC. Simulation results show that the proposed model is efficient for studying micro-grid system.

• Journal of the Korean Society of Safety
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• v.29 no.2
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• pp.31-37
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• 2014

For the vibration control of residential buildings, a multiple type slim damper system is developed and dynamic performance test is performed in this study. In conventional damping systems, larger installation space is required in order to achieve acceptable seismic performance, and as a result, it is difficult to determine efficient damping capacity of the device. The proposed damping device is composed of several small slim type dampers and linkage units. It can control damping capacity easily by changing the number of the small damper. To evaluate the proposed damping device, three slim type dampers (single-type, triple-type and penta-type) are designed and manufactured in real scale. Dynamic loading tests are performed by using the three manufactured dampers. From the tests, it is shown that damping coefficient is proportional to the number of the damper combined. Thus, test results validates the practicality of the proposed slim type dampers. applying nonlinear curve fitting technique, numerical model of the dampers are developed and presented.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.26 no.4
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• pp.221-230
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• 2019

Purpose: This study was done to examine incidence of diarrhea and explore factors influencing occurrence of diarrhea in patients admitted to intensive care units (ICU). Methods: For this retrospective research, data based on inclusion criteria were collected from the electronic medical records for 142 patients admitted to a university hospital ICU from September 2014 to August 2015. Statistical analysis was conducted using SPSS/WIN 22.0 program. Results: Incidence of diarrhea was 53.5% during the 12-month study period. Diarrhea occurred at 4.54 days and continued for 1.79 days on average. Average total frequency of diarrhea was 5.56 times. Increased ICU stay, enteral nutrition, and infection state were significant predictors of the occurrence of diarrhea. Infection increased risk of diarrhea 3.4 times and enteral nutrition increased risk of diarrhea to 2.2 times greater than patients not receivng enteral nutrition. Conclusion: Diarrhea in ICU patients is associated with multiple factors that should be considered to implement preventive strategies. Infection control should be emphasized, and close monitoring of diarrhea should be provided for those with enteral nutrition. Further studies are warranted to determine standardized clinical definition of diarrhea and diarrhea risk factors in ICU patients with different levels of severity and comorbidity.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.1
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• pp.22-32
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• 2018

Purpose: The study was done to examine hemodialysis unit nurses' knowledge on blood-borne infections, compliance and barriers to control and predictors of compliance. Methods: A descriptive correlational study was conducted with 122 nurses from hemodialysis units. Data were collected using a structured questionnaire. The data collection period was May to September, 2017. Data were analysed using descriptive statistics, t-test, ANOVA, Pearson correlation, and multiple linear regression. Results: The mean score for knowledge on blood-borne infections was $15.41{\pm}2.01$ out of 19 and the compliance with blood-borne infection control was $4.08{\pm}0.49$ out of 5. Barriers to the performance of blood-borne infections control were lack of time and personal protective devices. Knowledge on blood-borne infection did not correlate with compliance on blood-borne infection control (r=.13, p=.171). Predictors of compliance on blood-borne infections control were 1) infection control education on injuries caused by injection needles (${\beta}=.23$, p=.010), 2) infection control room (${\beta}=.24$, p=.006) and 3) blood exposure experience over the past week (${\beta}=-.24$, p=.005) and explained 22.2% of the variance (F=10.81, p<.001). Conclusion: Findings suggest that to improve the performance of blood-borne infectious disease management, customized education for nurses on blood-borne infection and systematic support related to the infection control room should be given priority.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.3
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• pp.222-227
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• 2011

2-axis tracking solar PV system applying a fixed-type unit than in the same area as the panel's power output to more than 140% can be obtained that have been identified. However, this approach compared with fixed or 1-axis control system and control the complexity of trekking equipment power the cursor comes to a relatively small output PV unit is called. In this paper, a small PV power units as a way to improve the economics of the small output of multiple PV units in the central control unit in enclosed places an intermittent manner by a remote control for each unit of the trek at the same time to simplify the control mechanism to reduce power that will be introduced. also the construction of large-scale PV development plans in difficult environments can be utilized in a manner appropriate to introduce.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1141-1142
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• 2011

An electrical vehicle (EV) is a huge issue in the automotive industry. The EV have many electrical units: electric motors, batteries, converters, ets. The DC power distribution system (PDS) is essential for the EV. The DC PDS offers many advantages. However, multiple loads in the DC PDS may affect the severe instability on the DC bus voltage. Therefore, a voltage bus conditioner (VBC) may use the DC PDS. The VBC is used to mitigate the voltage transient on the bus. In this paper, sliding mode controller (SMC) is designed for the VBC of DC PDS in the EV. The simulation results by PISM simulation package are presented for validating the proposed control technique.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.10
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• pp.81-92
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• 1995

In this paper, we present a high-level synthesis system that generates area-efficient RT-level datapaths with multiport memories. The proposed scheduling algorithm assigns an operation to a specific control step such that maximal sharing of functional units can be achieved with minimal number of memory ports, while satisfying given constraints. We propose a measure of multiport memory cost, MAV (Multiple Access Variable) which is defined as a variable accessed at several control steps , and overall memory cost is reduced by equally distributing the MAVs throughout all the control steps. Experimental results show the effectiveness of the proposed algorithm. When compared with previous approaches for several benchmarks available from literature, the proposed algorithm generates the datapaths with less memory modules and interconnection structures by reflecting the memory cost in the scheduling process.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.6-12
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• 2011

Electric vehicles and robots are real-time distributed control systems composed of multiple drive subsystems using micro controller units. Each control subsystem should be modular, compact, power saving, interoperable and fault tolerable in order to be incorporated into the networked real-time distributed control system. Under the networked real-time distributed control the synchronization problem can be occurred to the position and orientation tracking control due to the load variance, mismatch and time delay between the multiple drive subsystems. This paper suggests two types of position synchronization control of the single link manipulators. One of them is composed of cross controller, Kalman filter and disturbance observer, and the other uses the generation of target trajectories to minimize the gradient vector of the scalar function which is composed of the sum of square errors between the reference input vector and the output vectors. The availability of the proposed control schemes is shown through the control experiments.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1229-1234
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• 2009

The rolling stocks of KORAIL are KTX, Saemaulho Multiple Unit(PP), New Electrical Locomotive(DL), Electrical Locomotive(EL), Diesel Locomotive, Metropolitan Commuter Train(CDC), VVVF and Resistance Controlled Multiple Unit, etc. EMU with the maximum speed of 150km/h is under the test run at the moment. Electrical Multiple Units for mainlines with 180km/h speed are supposed to be introduced as a substitute for Saemaulho Multiple Unit which is scheduled to be out of service. But the specification standard for the control board design of train driver's cab does not exist and there is no a study for layout and type of controlling device with driver's ergonomical approach. That's why the types of controller and operating are different from rolling stocks, which has high possibility of driver's human error and needs education whenever a new car comes in. Based on the opinion poll of drivers, design specification of safety engineering and ergonomics for controlling devices and safety facilities can improve exact control for devices and deal quickly with an emergency so as to improve rolling stock safety and operational efficiency.

• Journal of Electrical Engineering and Technology
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• v.4 no.4
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• pp.457-466
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• 2009

This paper presents efficient parallel genetic algorithm (EPGA) based decomposed network for optimal power flow with various kinds of objective functions such as those including prohibited zones, multiple fuels, and multiple areas. Two coordinated sub problems are proposed: the first sub problem is an active power dispatch (APD) based parallel GA; a global database generated containing the best partitioned network: the second subproblem is an optimal setting of control variables such as generators voltages, tap position of tap changing transformers, and the dynamic reactive power of SVC Controllers installed at a critical buses. The proposed approach tested on IEEE 6-bus, IEEE 30-bus and to 15 generating units and compared with global optimization methods (GA, DE, FGA, PSO, MDE, ICA-PSO). The results show that the proposed approach can converge to the near solution and obtain a competitive solution with a reasonable time.