• Journal of Korean Society of Water and Wastewater
• /
• v.30 no.5
• /
• pp.491-500
• /
• 2016

Pressure monitoring is expected to be expanded in a water distribution system according to accelerated development of smart water network management technologies caused by appearances of affordable digital infrastructures like computing, storage and bandwidth. However, the placement of pressure sensors has been determined by engineer's technical decisions since there is no well-defined criteria for deciding a suitable location of pressure sensor. This study presents a placement method of pressure sensors based on the consideration of allowable error in calibrating water network analysis modeling. The proposed method is to find a minimum set of pressure sensors for achieving a reliable management of water transmissions main and increasing the efficiency of their real-time operation. In the case study in Y area's transmission main, the proposed method shows equally distributed pressure sensors in terms of hydraulics. It is expected that the proposed method can be used to manage transmission mains stably and construct a robust real-time network analysis system as a minimal criteria.

• Journal of IKEEE
• /
• v.24 no.1
• /
• pp.106-119
• /
• 2020

In this paper, we propose a control scheme for quadrotor system using a pole placement method. When using a state feedback controller, a lot of trial and error in selection of control gains are often required to improve system performance. In order to relax this complicated process, we analyze the closed-loop system associated with control gains. Then, we present a control gain selection algorithm for control gains using a pole placement method to improve the system performance. The proposed control method is applied to the actual quadrotor system to illustrate the validity of the proposed method.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.6
• /
• pp.437-441
• /
• 2009

Purpose: In many cases, the erroneous placement of a dental implant brings about undesirable results. Here, the effect of dental implant placement on the success of the final prosthesis was evaluated from the point of view of the prosthodontist. Materials and Methods: All surgical operations were performed by the same oral surgeon with the same surgical protocol and all prosthodontic procedures were performed by the same prosthodontist. The problems faced by the prosthodontist, their causes, and their effect on prosthesis success were identified. The success of the final prostheses was evaluated by the same prosthodontist. Results: Only 53% (238 implants in 105 patients) of dental implants were not associated with prosthodontic problems. Multiple implant placement (more than three implants) was associated more frequently with prosthodontic problems. Conclusions: The data indicate that the satisfactory construction of a prosthesis is highly dependent on the placement of the dental implant in the best possible position. It is strongly recommended that the oral surgeon and the prosthodontist engage in pre-operative discussions to establish a top-down treatment plan, as this will improve implant placement and ultimately the success of the prosthesis.

• Proceedings of the KIEE Conference
• /
• 1992.07a
• /
• pp.377-380
• /
• 1992

This paper proposes a novel direct adaptive pole placement control algorithm which can be applied to continuous time nonminimum phase systems. The algorithm is based on Lyapunov's direct method. By introducing an auxiliary signal, a minimal error model is constructed in state space. Using the error model an estimation law is obtained via Lyapunov's second stability theorem. The global stability of the overall system is established.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.25 no.9
• /
• pp.1046-1050
• /
• 1988

A direct adaptive control algorithm for discrete-time SISO systems with arbitrary zeros is presented in a general way by making use of reference model. A linear equation error model is formulated for estimating both the controller parameters and the auxiliary parameters. With this algorithm, asyptotic tracking within an arbitrarily small error can be achieved.

• 제어로봇시스템학회:학술대회논문집
• /
• 1991.10b
• /
• pp.1888-1893
• /
• 1991

Systematic design of a controller for a water temperature system was considered, with the intention of devising an accurate control experiment. The results of an experiment using a water temperature system based on the pole placement regulator showed water temperature oscillation and steady state error. This paper proposed a. method for eliminating both the oscillation and the steady state error. The oscillation was eliminated by a drive delay compensation technique, in which a future state value of the system was predicted through a real time computer simulation. The steady state error was eliminated by an steady state error correction technique, in which an actual steady state heatrate in the system model was replaced by an imaginary heatrate. By combining these two techniques, we obtained an experimental result for water temperature control of 0.01 (.deg. C) accuracy. Furthermore, the proposed method was evaluated relatively by comparing the experimental results using several other methods and proved to be the most accurate and convenient control method for the delay system.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.11
• /
• pp.34-41
• /
• 1997

This paper presents a technique to control a very flexible robot moving in a vertical plane. The flexible robot is modeled as an Euler-Bernoulli beam. Elastic deformation is approximated using the assmed modes method. A comparison function which satisfies all geometric and natural boundary conditions of a cantilever beam with an end mass is used as an assumed mode shape. Lagrange's equation is utilized for the development of a discretized model. A control algorithm is developed using a simple PID cnotrol tech- nique. The proportional, integral and deivative control gains are determined based on the dominant pole placement method and tuned to show no overshoot and no steady state error, and short settling time. The effectiveness of the developed control scheme is showed in the hub angular diaplacement control experiment. Three different end masses are uned in the experiment. The experimental results show that developed control algorithm is very effective showing little overshoot, no steady state error, and less than 2.5 second settl- ing time in case of having an end mass which is equivalent to 45% of the manipulator mass. Also the experimental results show that the residual vibration fo the end point is effectively controlled.

• The Korean Journal of Applied Statistics
• /
• v.31 no.5
• /
• pp.599-610
• /
• 2018

The method of Mack and Skillings (Technometrics, 23, 171-177, 1981) is a nonparametric multiple comparison method in a randomized block design with replications. This method is likely to result in loss of information because each block is ranked using the average of observations instead of repeated observations. In this paper, we proposed a new nonparametric multiple comparison method in the randomized block model with replications using an alignment method proposed by Hodges and Lehmann (The Annals of Mathematical Statistics, 33, 482-497, 1962) that extend the joint placement method proposed by Chung and Kim (Communications for Statistical Applications and Methods, 14, 551-560, 2007). In addition, Monte Carlo simulation compared the family wise error rate and power with the parametric method and the nonparametric method.

• Journal of the Korea Institute of Building Construction
• /
• v.6 no.4 s.22
• /
• pp.77-83
• /
• 2006

The purpose of this study is to measure the straightness of prefounded columns during underground construction stages. There are several causes of an error of prefounded column: (1) columns connected by welding or bolting, (2) by placement of concrete and aggregates around columns, (3) movement during construction, and (4) load applied during construction. The error of column straightness is different for each column, and the tilting of columns is shown in one or two directions between floors. The additional loads caused by the error of straightness may give damage to buildings. This paper presents the measurement results of column straightness, and thus providing a basis for further analysis.

• Journal of Institute of Control, Robotics and Systems
• /
• v.17 no.7
• /
• pp.619-624
• /
• 2011

This paper presents a controller design method for a robust control problem with multiple constraints using genetic algorithms and LMI design method. A robust $H_{\infty}$ constraint with loop shaping and pole placement is used to address disturbance attenuation with error limits and desired transient specifications, in spite of the plant uncertainties and disturbances. In addition, a loop gain constraint is considered so as not to enlarge the loop gain unnecessarily. The robust $H_{\infty}$ constraint and pole placement constraint can be expressed in terms of two matrix inequalities and the loop gain constraint can be considered as an objective function so that genetic algorithms can be applied. Accordingly, a robust controller can be obtained by integrating genetic algorithms with LMI approach. The proposed controller design method is applied to a track-following system of an optical disk drive and is evaluated through simulation results.