• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1663-1668
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• 2017

A BLDC motor with higher number of phases has several advantages, compared to the conventional three-phase BLDC motors. It can reduce the commutation torque ripple and the iron loss without increasing the voltage per phase and increase the reliability and power density. Higher number of phases increase the torque-per-ampere ratio for the same machine volume and output power by widening the electrical conduction period. In this paper, the proposed seven-phase BLDC motor drive system is made into several functional modular blocks, so that it can be easily extended to other ac motor applications: back-EMF block, hysteresis current control block, pwm inverter block, phase current block, and speed/torque control block. Also in a system of BLDC motor drive, the PI controller has been widely used in the speed controller because of the simple implementation. To obtain a good speed response in a general drive system using the PI controller, the high bandwidth of a controller is established. therefore, in this paper, a Fuzzy controller is applied to the 7-phase BLDC motor drive system in order to improve the speed control performance. The Fuzzy controller is compared with a conventional PI controller through the experiment with respect to speed dynamic responses. These experimental results show that the Fuzzy controller of the 7-phase BLDC motor drive system is superior over the conventional PI controller. The algorithm using the Fuzzy controller can improve a comfortable ride in the field of high performance 7-phase BLDC motor drive applications.

• Journal of IKEEE
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• v.22 no.4
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• pp.933-940
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• 2018

In this paper, we propose a multi-block deep learning structure for improving face recognition rate. The recognition structure of the proposed deep learning consists of three steps: multi-blocking of the input image, multi-block selection by facial feature numerical analysis, and perform deep learning of the selected multi-block. First, the input image is divided into 4 blocks by multi-block. Secondly, in the multi-block selection by feature analysis, the feature values of the quadruple multi-blocks are checked, and only the blocks with many features are selected. The third step is to perform deep learning with the selected multi-block, and the result is obtained as an efficient block with high feature value by performing recognition on the deep learning model in which the selected multi-block part is learned. To evaluate the performance of the proposed deep learning structure, we used CAS-PEAL face database. Experimental results show that the proposed multi-block deep learning structure shows 2.3% higher face recognition rate than the existing deep learning structure.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.643-646
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• 1987

A criterion is developed for the, selection of the best pairing of the control and manipulated variables and for the interaction analysis of decentralized multi-input multi-output control systems. This criterion is based on the difficulty caused by the interaction terms in finding the in-verse of the block steady gain matrix. A quantitative measure of the best pairing is obtained from the resemblance of a set of independent block multi-loop systems. Several examples show the validity of the pairing criterion.

• Bulletin of the Korean Chemical Society
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• v.35 no.9
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• pp.2689-2693
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• 2014

The control over microstructure in block copolymer thin films using external electric fields has become an interesting research topic. In this article, the effect of nanoparticle on the microdomain alignments in block copolymer (polystyrene-b-poly(2-vinylpyridine)/nanoparticle (Au) thin films under electric fields has been examined with transmission electron microscopy. The homogeneous dispersion of Au nanoparticles into the block copolymer matrix was achieved by surface modification of nanoparticles with compatible ligands. Compared with the phenomenon seen in the pristine block copolymer thin films, a peculiar alignment behavior was observed in the block copolymer/nanoparticle hybrid thin films under electric fields. In addition, the different pathways observed in the pristine and nanoparticle incorporated block copolymer thin films were also monitored as a function of exposure time. This work can provide the fundamental information for understanding microdomain alignment in block copolymer/nanoparticle thin films under external electric fields.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.20-23
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• 1996

The block matching algorithm for the motion estimation is relatively simple to implement, and thus widely applied in image sequence coding such as H.261, MPEG- I and MPEG-2. Most techniques of the block matching method use fixed-size blocks for the motion estimation. And their success relies on the assumption that the motion within each block is uniform. But if the block size is increased to reduce the number of motion vectors for high data compression, the estimated image brings about many errors. In this paper, the variable-sized blocks are used to solve this problem. And the top down method is used to select the block size.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1043-1048
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• 2009

PES (Programmable Electronic System) is used by software development for the train control system. PES has been widely used in real world and consists of hardware, firmware and application software. The PES are easily apply to many applications because its implementation has high flexibility. Many safety critical functions are realized through software in safety critical system. Normally, it is difficult to detect failures for PES system because the PES is too sophisticated to identify sources of the failure. So, the reliability analysis is needed by using software fault tolerance techniques. Currently, there are the recovery block, distributed recovery block, N-version programming, N self-checking programming in fault tolerance techniques. In this paper, the models of recovery block and N-version programming in software fault tolerance techniques are suggested by using the Markov model. Also, the reliability in the train control system is analyzed through changing time. The fault occupancy rates of the program, adjustment test and voter are stationary. So, the relation between time and reliability is presented by using Matlab program. In the result of reliability, the reliability of recovery block is more high than N-version programming in case of the same number of substitution block.

• Journal of Medicine and Life Science
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• v.18 no.1
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• pp.11-15
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• 2021

In elderly patients, the vital parameters tend to fluctuate based on the blood volume status, which may cause sudden hypovolemic shock if the postoperative bleeding continues. Particularly, those who undergo surgery for arthritis needs to pay extra attention because the bleeding may persist over the joints after the surgery. Therefore, appropriate pain control is required to reduce the postoperative blood loss. This retrospective chart review study was conducted to assess the postoperative pain control and reduction of blood loss with a single injection of saphenous nerve block (SNB) in elderly patients with osteoarthritis. We reviewed the electronic medical records of patients who underwent knee total arthroplasty with spinal anesthesia between January and May 2016. A total of 51 patients participated in this study. All patients were treated with intravenous patient-controlled analgesia for the postoperative pain control, and additional analgesic agents were administered at a visual analogue scale above a score of 6. In 25 patients, SNB was performed using ultrasound with the administration of 0.75% ropivacaine (15 mL) after the surgery. Patients who received additional analgesics were significantly low in the nerve block group (P=0.009). Additionally, the volume of blood loss from catheter drainage was significantly low at 2 and 3 days postoperatively (P=0.013 and P=0.041, respectively) in the nerve block group. In patients who underwent total knee arthroplasty with osteoarthritis, only a single injection of saphenous nerve block was sufficient for the postoperative pain control and reduced bleeding.

• The Journal of the Korean dental association
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• v.56 no.1
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• pp.49-57
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• 2018

The most widely used method of pain control in dental practice is to block the pathway of painful impulses by local anesthesia. For a maximum effect of pain control at outpatient minor operation, regional anesthesia including nerve block must be performed. This issue includes various dental local anesthetic techniques on mandible, maxilla and considerations for selection of dental local anesthetics according to patient's age, duration of operation. Additionally, current conscious sedation technique combined with local anesthesia will be introduced for control of patient's anxiousness. Based on patient's general condition, severity of operation, local anesthesia sometimes must be changed into general anesthesia to avoid failure of dental practice. The exact choice of anesthetic techniques for minor operations at dental outpatient clinic must not be underestimated for complete success of pain control.

• Journal of Institute of Control, Robotics and Systems
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• v.4 no.5
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• pp.574-578
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• 1998

This paper considers the robust positive real problem for linear systems with linear fractional-type norm-bounded repeated scalar block parameter uncertainty. It is shown that the robust positive real problem can be converted into the standard positive real problem without uncertainty that can be used for the analysis of the given uncertain linear system and the synthesis of a controller that robustly stabilizes and achieves the extended strict positive realness property of the closed-loop transfer function. These results can be also applied to the linear system with general structured uncertainty containing repeated scalar block parameters and are extensions of the previous works that consider only norm-boundedness of the affine unstructured uncertainty.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10b
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• pp.969-973
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• 1990

This paper presents a method of suboptimal control for nonlinear systems via block pulse transformation. The adaptive optimal control scheme proposed by J.P. Matuszewski is introduced to minimize the performance index. Nonlinear systems are controlled using the obtained optimal control via block pulse transformation. The proposed method is simple and computationally advantageous. Viablity of the this method is established with simulation results for the van der Pol equation for comparision with other methods.