• Journal of Power Electronics
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• v.17 no.2
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• pp.368-379
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• 2017

In this paper, a direct torque control algorithm with novel duty cycle-based modulation is proposed for permanent magnet synchronous motor drives fed by neutral-point clamped three-level inverters. Compared with the standard DTC, the proposed algorithm can suppress steady-state torque ripples as well as ensure neutral-point potential balance and smooth vector switching. A unified torque/flux evaluation table with multiple voltage vectors and precise control levels is established and used in this method. This table can be used to evaluate the effects of duty-cycle vectors on torque and flux directly, and the elements of the table are independent of the motor parameters. Consequently, a high number of appropriate voltage vectors and their corresponding duty cycles can be selected as candidate vectors to reduce torque ripples by looking up the table. Furthermore, small vectors are incorporated into the table to ensure the neutral-point potential balance with the numerous candidate vectors. The feasibility and effectiveness of the proposed algorithm are verified by both simulations and experiments.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.163-169
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• 2003

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers load and the centrifugal force by rotation of table. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to 30% of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner for vertical roller mill using HDM and fatigue analysis

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1998.06a
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• pp.596-700
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• 1998

Nowadays, with increasing many vehicles on restricted roads, the conventional traffic light creates prove startup-delaytime and end-lag-time. The conventional traffic light loses the function of optimal cycle. And so, 30∼45% of conventional traffic cycle is not matched to the present traffic cycle. In this paper proposes electrosensitive traffic light using fuzzy look up table method which will reduce the average vehicle waiting time and improve average vehicle speed. Computer simulation results prove that reducing the average vehicle waiting time which proposed considering passing vehicle length for optimal traffic cycle is better than fixed signal method which doesn't consider vehicle length.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 1996.10a
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• pp.198-207
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• 1996

Electro sensitive traffic system can't consider passenger car unit, so, it causes start up delay time and passenger waiting time. In this paper, it antecedently creates optimal traffic cycle of passenger car unit at the bottom traffic intersection. But, sometimes it can make mistakes due to changes in car weight, car speed, and control of feed-back data. Moreover, to prevent spillback, it can adapt control even though upper traffic intersection has a different saturation rate, road length, road slope and road width.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.3 no.1
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• pp.105-111
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• 2003

This paper is researching the storing of 40 different kinds of conditions. Such as, car speed, delay in starting time and the volume of cars in traffic. Through the use of a central nervous networking system or AI, using 10 different intersecting roads. We will improve the green traffic light. And allow more cars to easily flow through the intersections. Now days, with increasing many vehicles on restricted roads, the conventional traffic light creates prove startup-delay time and end-lag-time. The conventional traffic light loses the function of optimal cycle. And so, 30-45% of conventional traffic cycle is not matched to the present traffic cycle. In this paper proposes electro sensitive traffic light using fuzzy look up table method which will reduce the average vehicle waiting time and improve average vehicle speed. Computer simulation results prove that reducing the average vehicle waiting time which proposed considering passing vehicle length for optimal traffic cycle is better than fixed signal method which dosen't consider vehicle length.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.8 s.227
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• pp.1221-1228
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• 2004

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers load and the centrifugal force by rotation of table. It demands $4{\times}10^7$ cycle but has $4{\times}10^6{\sim}8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller. The repair expense for it amounts to $30\%$ of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner for vertical roller mill using HDM and fatigue analysis and makes the estimation for safety of vertical roller mill.

• The Korean Journal of Physiology
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• v.15 no.1
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• pp.45-51
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• 1981

The aim of this study was to investigate the pulmonary function tests of athletes related to Running, Swimming, Cycle, Taekwando, Wrestling, Boxing, Yudo, Badminton, Base-ball, Soccer, Hand-ball, Basket-ball and Volley-ball. Subjects were 269 athletes from 18 to 22 years of age. They were college students and citizens. The results are as follows: 1) Frequency of breath: (cycles/min., $M{\pm}S.D$) Running shows $13{\pm}3.6$, Swimming $12{\pm}3.2$, Cycle $13{\pm}3.4$, Taekwondo $12{\pm}4.0$, Wrestling $14{\pm}2.5$, Boxing $15{\pm}4.5$, Yudo $13{\pm}3.2$, Badminton $14{\pm}5.7$, Base-ball $15{\pm}6.2$, Soccer $13{\pm}2.5$, Hand-ball $14{\pm}2.5$, Basket-ball $12{\pm}5.6$, Volley-ball $12{\pm}4.2$(Table 2, Fig. 1). 2) Vital capacity: (1, $M{\pm}S.D$) Running shows $4.29{\pm}0.634$, Swimming $4.30{\pm}0.608$, Cycle $4.08{\pm}0.718$, Taekwondo $4.32{\pm}0.595$, Wrestling $4.40{\pm}0.663$, Boxing $4.45{\pm}0.779$, Yudo $4.58{\pm}0.389$, Badminton $3.98{\pm}0.556$, Base-ball $3.99{\pm}0.617$, Soccer $4.42{\pm}0.728$, Hand-ball $4.23{\pm}0.397$, Basket-ball $4.28{\pm}0.426$, Volley-ball $4.60{\pm}0.620$(Table 2, Table 3, Fig. 2). 3) Tidal volume: (ml, $M{\pm}S.D$) Running shows $615{\pm}180$, Swimming $603{\pm}121$, Cycle $529{\pm}189$, Taekwondo $726{\pm}112$, Wrestling $512{\pm}90$, Boxing$622{\pm}134$, Yudo $583{\pm}89$, Badminton $672{\pm}121$, Base-ball $714{\pm}97$, Soccer $579{\pm}89$, Hand-ball $507{\pm}69$, Basket-ball $628{\pm}133$, Volley-ball $597{\pm}144$(Table 2, Fig.3). 4) Breath holding time : (sec., $M{\pm}S.D$) Running shows $64{\pm}18.8$, Swimming $81{\pm}23.0$, Cycle $54{\pm}13.6$, Taekwondo $55{\pm}11.8$, Wrestling $78{\pm}12.5$, Boxing $63{\pm}9.6$, Yudo $71{\pm}14.4$, Badminton $62{\pm}9.8$, Base-ball $58{\pm}8.9$, Soccer $65{\pm}10.9$, Hand-ball $66{\pm}7.6$, Basket-ball $62{\pm}8.8$, Volley-ball $57{\pm}13.4$(Table 2, Fig.4).

• Kyungpook Mathematical Journal
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• v.63 no.4
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• pp.709-718
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• 2023

The inner automorphism groups of quandles are related to the classification problem of quandles. The inner automorphism group of a quandle is generated by inner automorphisms which are presented by columns in the operation table of the quandle. In this paper, we describe inner automorphisms of an abelian extension of a quandle by expressing columns of the operation table of the extended quandle as columns of the operation table of the original quandle. Such a description will be helpful in studying inner automorphism groups of abelian extensions of quandles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.8
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• pp.60-65
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• 2022

This study focuses on the driving control design of an index, which is a key component of a rotary transfer machine that is effective in improving productivity and reducing manufacturing costs by shortening cycle time. Although various index studies have been conducted on the rotation of workpieces such as general-purpose machine tools and tilting indices, the development of an index for rotary transfer machines for transfer is insufficient. The index consists of a body, table, hydraulic cylinder, motor, reducer, and curved coupling. The torque of the table for driving was selected, and the angular velocity and torque pattern were simulated using the motor manufacturer's program. The specifications of the drive motor were determined based on the selected torque.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.97-105
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• 2004

The vertical roller mill is the important machine grinding and mixing various crude materials in the manufacturing process of portland cement. Table liner is one of grinding elements of vertical roller mill and is subjected to the cyclic bending stress by rollers and the centrifugal force by rotation of table. It demands $4{\times}10^7$ expense of life but has $4{\times}10^6~-8{\times}10^6$ cycle. It fractures at the edge of grinding path of outside roller The repair expense fur it amounts to 30% of total maintenance of vertical roller mill. Therefore, this study shows the fracture mechanism of table liner of vertical roller mill using HDM and fatigue analysis