• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2414-2419
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• 2012

This paper presents an optimal operation control method for energy saving in the water reuse pumping system. A predictive horizon switching strategy is proposed to implement an optimal operation control and a linear programming (LP) algorithm is used to solve optimal problems in each time step. Energy costs are calculated for electricity on both TOU in the light, heavy, and maximum load time period and peak charges. The optimal operation in water reuse pumping systems is determined to reduce the TOU and peak costs. The simulation results show a power energy saving for water reuse pumping systems and power stability improvement.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1897-1902
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• 2008

The computer system is used in many application domains and any system error in these domains may either cause critical loss or threaten environment or human life. Though examples of these domains can be found in many areas, the system, which is used in domains for carrying passengers including rolling stocks in particular, is expected to show satisfactory operation all the time. The relay control logic, which is used in rolling stocks, is complex in hardware and occupies considerably large volume. Nevertheless, it has been used for a long time, to let the system safely operate even in the occurrence of an error in the computer system. However, the relay control logic circuit is so complex that the analysis of proper circuit operation and interlocking tends to be dependent only on the designer's experiences instead of being systematically performed. Especially, the analysis following a change, addition and deletion of a previous circuit according to the requirements from a source of demand is significantly limited. In this paper, the accuracy of relay control logic is verified by the use of properties of Petri Net model. In addition, how main circuit breaker (MCB) control circuit is modeled and analyzed by the design methodology is shown.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.67-73
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• 1999

In order to increase the enzymatic activity of malt used as a source of traditional processing foods, the enzymatic activities of various barley were examined and the effects of ozone and light illumination treatment on the enzymatic activities of amylase, amylase, and glucanase in malt during man ufacture were also examined. Barley didn't show amylase activity prior to soaking, but the activity of barley increased quickly after soaking. Glutinous barley showed the highest amylase activity among Duru barley, Ol barley, two rowed barley and naked barley. Naked barley showed the lowest activity. The amylase activity was the highest in Duru barley and decreased in the order of in glutinous barley, naked barley and two rowed barley. It was showed that the enzymatic activity of malt was higher than that of control when malt was soaked for 24hr at the concentration of 0.3ppm of ozone. The enzymatic activity of malt treated with light illumination was higher than that of control. The bud and root of light illuminated malt was much stronger than that of control. The root of light illuminated malt was much shorter than that of control. In addition, light illuminated malt showed a little green color which matches the demand of consumer. These studies demonstrated that both ozone and light illumination treatment increased the enzymatic activity of malt to result in high quality of malt manufacture.

• Journal of Drive and Control
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• v.11 no.4
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• pp.53-60
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• 2014

This paper proposes a control scheme to reduce the power consumption of a variable displacement swash-plate type piston pump supplying oil to a valve-controlled hydraulic cylinder at constant pressure. Whenever flow rate demand was absent, the swash plate angle and the pump speed were changed to the minimum values required to compensate for the internal leakage flow. In response to command signals, the pump speed was changed in proportion to the absolute mean value of the speed component for position commands. At the same time, a pressure regulator was activated to maintain constant system pressure by precisely adjusting the pump speed with the swash plate angle fixed at the maximum. The conventional system consisting of a pressure-compensated variable displacement type pump is driven at a constant speed of 1,800rpm. By comparison, computer simulation and experimental results showed that idling power at stand-by status could be reduced by up to 70% by reducing the pump speed from 1,800rpm to 300rpm and the swash plate angle to the minimum.

• Korean Journal of Occupational Health Nursing
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• v.18 no.1
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• pp.106-115
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• 2009

Purpose: Occupational stress is a determinant risk factor for cardiovascular disease and work disability. This study aims to describe occupational stress and identify its related factors among aged security guards. Methods: A random sample of 76 aged security guards were interviewed by three research assistants. The criteria of the subjects were as follows : 50 or older male with 40 or more working hours a week working with colleagues ranged from 3 to 50. The data were collected in September, 2007 and analyzed by multiple regression using SAS Version 9.1. Results: The mean score of occupational stress among aged security guards was 47.2. The mean scores of its sub-scales were 31.3(physical environment), 33.8(occupational demand), 80.8occupational control), 44.6(interpersonal conflict), 51.3 (occupational insecurity), 53.6(occupational system), 57.5(lack of reward), and 30.3(work environment). The scores of occupational control, interpersonal conflict, and occupational insecurity were higher than the scores of Korean average occupational stress sub-scales. Significant variables affecting occupational stress and its sub-scales were work place, work type, and employment type. Conclusion: In order to reduce occupational stress among security guards, sufficient occupational control and interpersonal conflict control, appropriate reward, and employment stability should be considered. Also long working hours and work shift should be improved.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.545-548
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• 2015

As society is evolving into a highly smart era, a demand on convenient and safe living environment is increasing and many studies are being progressed in the directions of seeking convenience, safety and comfort in living. Therefore in this paper, a method for controlling the devices within the living space using a smart device and transmitting the information measured from a variety of sensors such as temperature, humidity and gas, etc using the Bluetooth was proposed in order to provide the convenience and safety of living environment.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.1003-1006
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• 2005

Demand of Auto Focus for Camera module is increased very fast in these days and will be adapted to most of mobile phones in next few years instead of traditional method, fixed focus. To make auto focus function, 2 kinds of solutions, VCM(Voice Coil Motor) and Piezo linear motor are normally used. In this paper, VCM which commercially strong candidate for Auto focus mechanism was investigated to verify principles are match up to the actual operation. Auto focus algorithm is different between 1 chip and 2 chip solution. Normally 2 chip is more complicate than the other. To have best performance on this function, hysteresis and depth of field(DOF) table should be optimized.

• Smart Structures and Systems
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• v.24 no.1
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• pp.1-14
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• 2019

Transmission tower-line system is one of most critical lifeline systems to cities. However, it is found that the transmission tower-line system is prone to be damaged by earthquakes in past decades. To mitigate seismic demands, this study introduces a tuned-mass damper (TMD) using superelastic shape memory alloy (SMA) spring for the system. In addition, considering the dynamic characteristics of both tower-line system and SMA are affected by temperature change. Particular attention is paid on the effect of temperature variation on seismic behavior. In doing so, the SMA-TMD is installed into the system, and its properties are optimized through parametric analyses. The considered temperature range is from -40 to $40^{\circ}C$. The seismic control effect of using SMA-TMD is investigated under the considered temperatures. Interested seismic performance indices include peak displacement and peak acceleration at the tower top and the height-wise deformation. Parametric analyses on seismic intensity and frequency ratio were carried out as well. This study indicates that the nonlinear behavior of SMA-TMD is critical to the control effect, and proper tuning before application is advisable. Seismic demand mitigation is always achieved in this wide temperature range, and the control effect is increased at high temperatures.

• The Journal of Information Systems
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• v.31 no.4
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• pp.47-73
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• 2022

Purpose The purpose of this study is to select the electronic architecture concept of the powertrain domain of the electronic platform to be applied to electric vehicles after 2025. Previously, the automotive electrical and electronic architecture was determined only by trend analysis, but the purpose was to determine the scenario based on the data and select it with clear evaluation indicators. Design/methodology/approach This study identified the function to be applied to the powertrain domain of next-generation electric vehicle, estimated the controller, defined the function feature list, organized the scenario candidates with the controller list and function feature list, and selected the final architecture scenario. Findings According to the research results, the powertrain domain of electric vehicles was selected as the architectural concept to apply the DCU (Domain Control Unit) and VCU (Vehicle Control Unit) integrated architecture to next-generation electric vehicles. Although it is disadvantageous or equivalent in terms of cost, it was found to be excellent in most indicators such as stability, security, and hardware demand.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.24-33
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• 1996

PLCs are vital components of modern automation systems, which have penetrated into almost every industry. Many industries have a demand for facilitation of PLC programming. In this study, a programning system for sequential control is developed on a personal computer. This programming system consists of two main parts, a GRAFCET editor and a GRAFCET compiler. The GRAFCET editor enables us to model an actual sequential process by a GRAFCET diagram. This GRAFCET editor is developed by the menu-driven method based on specific menus and graphic symbols. The GRAFCET compiler consists of two parts, a GRAFCET parser and a code generator. The possible errors in a drawn GRAFCET diagram are first checked by the GRAFCET parser which generates finally an intermediate code from a verified CRAFCET diagram. Then the intermediate code is converted into a control code of an actual sequential controller by the code generator. To show the usefulness of this programming system, this system is applied to a pneumatically controlled handling robot. For this robot, a Z-80 microprocessor is used as the actual sequential controller.