• 제어로봇시스템학회:학술대회논문집
• /
• 1992.10a
• /
• pp.747-753
• /
• 1992

The modeling and control design schemes are developed for maglev systems with a combined lift and guidance. First, bond graph techniques are applied for modeling these multi-energy domain systems more logically and systematically. And the stability loop via pole placement and the performance loop via loop-shaping LQ control are designed. The suggested controller satisfies the required characteristics of stability and performance simultaneously. Finally, the robustness of the synthesized maglev control system is evaluated for the variations of air gap and vehicle mass through computer simulation.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.10
• /
• pp.1881-1887
• /
• 2009

This paper discusses the effects of ECC (Earth Continuity Conductor) for reducing the level of induced sheath overvoltages at the single point bonded section of combined transmission lines which are mixed underground power cable with overhead line in one T/L. In previous papers, the characteristics of ECC on only underground power cable systems were sufficiently analyzed. However, the result of only underground power cable systems are totally different from that of combined transmission lines because ECC is commonly grounded with overhead grounding wire at mesh of cable head. Therefore, in this paper, the installation effects of ECC have been variously analyzed considering the three kinds of fault positions, cable formation of duct and trefoil, spacing between phase conductor and ECC, and the change of overhead transmission line section length on 154kV combined transmission line. Finally, simulation results show that ECC can effectively reduce the induced sheath voltage.

• Journal of Korean Society of Water and Wastewater
• /
• v.29 no.1
• /
• pp.1-9
• /
• 2015

A combined treatment system using multiple source water is becoming important as an alternative to conventional water supply for small-scale water systems. In this research, combined water treatment systems were investigated for simultaneous use of multi-source water including rainwater, ground water, river water, and reclaimed wastewater. A laboratory-scale system was developed to systematically compare various combinations of water treatment processes, including sand filtration, microfiltration (MF), granular activated carbon (GAC), and nanofiltration (NF). Results showed that the efficiency of combined water treatment systems was affected by the quality of feed waters. In addition, a simply approach based on the concept of linear combination was suggested to support a decision-making for the optimum water treatment systems with the consideration of final water quality.

• Journal of Mechanical Science and Technology
• /
• v.20 no.9
• /
• pp.1502-1513
• /
• 2006

This study analyzes the design and part load performance of a power generation system combining a micro gas turbine (MGT) and an organic Rankine cycle (ORC). Design performances of cycles adopting several different organic fluids are analyzed and compared with performance of the steam based cycle. All of the organic fluids recover greater MGT exhaust heat than the steam cycle (much lower stack temperature), but their bottoming cycle efficiencies are lower. R123 provides higher combined cycle efficiency than steam does. The efficiencies of the combined cycle with organic fluids are maximized when the turbine exhaust heat of the MGT is fully recovered at the MGT recuperator, whereas the efficiency of the combined cycle with steam shows an almost reverse trend. Since organic fluids have much higher density than steam, they allow more compact systems. The efficiency of the combined cycle, based on a MGT with 30 percent efficiency, can reach almost 40 percent. hlso, the part load operation of the combined system is analyzed. Two representative power control methods are considered and their performances are compared. The variable speed control of the MGT exhibits far better combined cycle part load efficiency than the fuel only control despite slightly lower bottoming cycle performance.

• Coupled systems mechanics
• /
• v.11 no.3
• /
• pp.233-257
• /
• 2022

This work presents a comparative study between two different models: trapezoidal and T-shaped combined footings. The comparative study between trapezoidal and T-shaped combined footings presented in this paper generatesresultsthat have an unparalleled accuracy for all foundation engineering problems. The main part of this research is to obtain the optimal area, reinforcing steel, and thickness of the trapezoidal and T-shaped combined footings using the new models. The comparison is made for two trapezoidal combined footings and two T-shaped combined footings ofreinforced concrete subjected to the same load.Themain findings are: themodelfortrapezoidal combined footings can be used for rectangular and triangular, and the T-shaped combined footings can be used for rectangular. The structure of the paper is asfollowsfirst a very complete state of the art with extensive referencesthat describesthe methodology used for the different models clearly, presents different numerical examples, results and at the end conclusions.

• Proceedings of the KIEE Conference
• /
• 2005.11b
• /
• pp.280-282
• /
• 2005

This paper describes switching overvoltage generated during transient state in 22.9kV combined distribution systems. For analysis, distribution overhead line, underground cable and surge arrester are modeled using EMTP/ATPDraw. Simulation results show switching overvoltage according to various kind of parameter and systems such as closing angle and cable length.

• Journal of Institute of Control, Robotics and Systems
• /
• v.8 no.9
• /
• pp.788-794
• /
• 2002

To improve surgical result of total hip arthroplasty (THA), there has been some approaches using a robotic milling system, which can make a precise cavity in the femur. Usually, to carve a femur, the surgical robot is controlled by a pre-programmed tool-path regardless of a surgeon's experience and Judgment. This paper presents a control method of a surgical robot for THA, which can be used as an advanced surgical tool. With a master/slave combined surgical robot, surgeon can directly control the motion and velocity of a surgical robot. The master/slave-combined robot is controlled to display a specific admittance for a surgeon's force to the surgical robot velocity. To prevent the over-carving of a femur, virtual hard wall is displayed on the surgical boundary. To evaluate the proposed control method of the master/slave-combined surgical robot, 2-DOF master/slave-combined manipulator is used in experiment.

• International Journal of Railway
• /
• v.5 no.2
• /
• pp.77-83
• /
• 2012

Railroad signaling systems are to control intervals and routes of trains. There are ATS, ATP, ATO and ATC system. Trains are operated in the section which is met on the signaling system because various signaling systems are used in Korea. Hence, trains are not operated in the section which is used in the other signaling system. To solve this problem, recently combined on-board system has been developed. The combined on-board system designed by doubling the ATS, ATP and ATC system to ensure the safety of system. The inductance of antenna is change and in return the resonance frequency of antenna is varied by the electromagnetic induction. Therefore, the information signal is not received exactly in the combined on-board system and in return accidents between trains occur. In this paper, electric model of the combined on-board system for considering the ATS and ATP antenna is presented. Moreover, the mutual inductance including the distance between the ATS and ATP antenna is calculated. As a result of the frequency response of the antennas, the mutual inductance met on operation range of resonance frequency is defined.

• Management & Information Systems Review
• /
• v.6
• /
• pp.137-162
• /
• 2001

Our business conglomerates are sharing their fates economically because of mutual debt warranty among their own affiliates and excessive financial loans. For this reason, it is inevitably restrictive to obtain the whole information on such conglomerates by individual and consolidated financial statements. To solve this problem, the system of combined financial statement was introduced through modifications of the Act of the outside audit of corporations in 1988. As a result, 15 out of this nation's 30 major business conglomerates prepared and submitted their own combined financial statements. In this paper, all financial statements are grouped into financial and non-financial parts, based on characteristics of business control and combined financial statement. Then the business size, financial rate and internal transactions for each of the conglomerates are analyzed, based on which problems of the combined financial statement as announced publicly are clarified. For the system, this study suggests improvement points such as a sufficient publication of any possible situations and interest coordination caused between the date of business settlement and that of preparing combined financial statements by applying principles of sharing to the evaluation of valuable instrument papers for investment and by determining the amount, 5% accounting for the total amount of debt warranty, foreign exchange assets and debts.

• Journal of Power Electronics
• /
• v.11 no.5
• /
• pp.734-742
• /
• 2011

In this paper a robust method is presented for the combined design of STATCOM and Power System Stabilizer (PSS) controllers in order to enhance the damping of the low frequency oscillations in power systems. The combined design problems among PSS and STATCOM internal ac and dc voltage controllers has been taken into consideration. The equations that describe the proposed system have been linearized and a Fuzzy Logic Controller (FLC) has been designed for the PSS. Then, the Particle Swarm Optimization technique (PSO) which has a strong ability to find the most optimistic results is employed to search for the optimal STATCOM controller parameters. The proposed controllers are evaluated on a single machine infinite bus power system with the STATCOM installed in the midpoint of the transmission line. The results analysis reveals that the combined design has an excellent capability in damping a power system's low frequency oscillations, and that it greatly enhances the dynamic stability of power systems. Moreover, a system performance analysis under different operating conditions and some performance indices studies show the effectiveness of the combined design.