• Journal of Power Electronics
• /
• v.8 no.4
• /
• pp.317-324
• /
• 2008

This paper proposes a Multiband Shunt Hybrid Active Filter (SHAF) with sensorless control. A plant is modeled in the discrete- time domain and a controller is designed using the Pole shifting law in the polynomial domain. This control approach is very useful for filtering the load harmonics with reduced sensor counts where a low cost solution like SHAF is required. Multiple Synchronous Reference Frames (MSRF) and low pass filters are used to measure the $5^{th}$ and $7^{th}$ harmonic components separately from the load and filter currents. Individual current controllers are designed for the $5^{th}$ and $7^{th}$ harmonic currents. Control is realized in the stationary, three-phase (abc) reference frame. Performance of the controller is validated through simulation, using realistic plant and controller models, as well as experimentally on a full-scale distribution system.

• Proceedings of the KIEE Conference
• /
• 1998.07b
• /
• pp.592-594
• /
• 1998

In the single-input and single-output system, the parameter of plant is scalar polynomial, but in the multiple input and multiple output, it accompanies, being matrix polynomial, the consideration of observable conrolability index or problems of non-commutation in matrix polynomial as well as degree, and it is more complex to deal with. Therefore, it is thought that a full reserach on the single-input and single-output system is not made. This reserach propose that problems of minimum variance self-tuning regulator of multivariable system and pole placement self-tuning regulator.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.1
• /
• pp.32-39
• /
• 2012

With the aid of genetic algorithm (GA), global optimization with multiple geometry parameters is feasible in the design of switched flux permanent magnet (SFPM) machines. To investigate the advantages of global optimization over individual optimization, which has been used extensively for the design of SFPM machines, a comparison between the two approaches is carried out for the case of fixed copper loss and volume. In the case of individual parameter optimization, the sequence in which the individual parameters are optimized is very important. In the global optimization a better design can always be achieved although the corresponding torque density is found to be only slightly better than that of individually optimized with correct design sequence. By using the obtained global optimization results, the performance in machines having two types of stator and rotor pole combinations, i.e. 12/10 and 12/14, are compared, and it is shown that higher torque is exhibited in the 12/14 SFPM machine. Finally, this paper also demonstrates that global optimization, with the restriction of equal pole width, magnet thickness and slot opening, can maximize the torque density without significantly sacrificing other performance, such as cogging torque and overload capability.

• Archives of Craniofacial Surgery
• /
• v.10 no.2
• /
• pp.135-137
• /
• 2009

Purpose: Nevus comedonicus is a rare disease involving abnormal development of the pilosebaceous unit, clinically appearing confluent clusters of open comedones. It is characterized by follicular epidermic invaginations filled with keratin, with atrophic pilose or sebaceous structures which are open to the lower pole of the invagination. We report a child with inflammatory pustules and cysts correlated to the nevus comedonicus. Methods: A 15-month-old girl was referred for treatment of a nevus comedonicus that has been developed since birth. There were periodic episodes of erythema and swelling of the plaque. The patient had treated previously with retinoid cream for 2 weeks without obvious benefit at dermatology clinic. We excised the nevus comedonicus with Y-shape leaving some lesions. Results: When we incised skin, we could see multiple large whitish cysts beneath the nevus comedonicus. Histopathologic findings showed deep invagination of epidermis filled with keratin plugs, keratinous cyst in the dermis, rudimentary hair follicle. Conclusion: We treated rare nevus comedonicus with multiple large cysts as surgical excision.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.847-852
• /
• 2007

This paper investigates the characteristics of cogging torque and magnetic force of a brushless DC (BLDC) motor due to imperfect magnetization of permanent magnet (PM) numerically and experimentally which results in the magnetically induced vibration. A predicted magnetization pattern of the PM of the BLDC motor, which is derived from the measured surface magnetic flux density along the PM, is applied to the finite element analysis in order to calculate the cogging torque and the unbalanced magnetic force. This research also develops the experimental setup to measure the unbalanced magnetic force as well as the cogging torque. It shows numerically and experimentally that the imperfect magnetization of permanent magnet generates the driving frequencies of cogging torque with integer multiple of slot number in addition to the least common multiple of pole and slot. It also shows that the driving frequencies of unbalanced magnetic force are integer multiple of slot number ${\pm}1$ due to imperfect magnetization of PM even in the rotationally symmetric design.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.21 no.6
• /
• pp.634-639
• /
• 2020

In general, the stability and response characteristics of the system can be improved by changing the pole position because a nonlinear system can be linearized by the product of a 1st and 2nd order system. Therefore, a controller that moves the pole can be designed in various ways. Among the other methods, LQ control ensures the stability of the system. On the other hand, it is difficult to specify the location of the pole arbitrarily because the desired response characteristic is obtained by selecting the weighting matrix by trial and error. This paper evaluated a method of selecting a weighting matrix of LQ control that moves multiple double poles with Jordan blocks to real poles. The relational equation between the double poles and weighting matrices were derived from the characteristic equation of the Hamiltonian system with a diagonal control weighting matrix and a state weighting matrix represented by two variables (ρ_d, ϕ_d). The Moving-Range was obtained under the condition that the state-weighting matrix becomes a positive semi-definite matrix. This paper proposes a method of selecting poles in this range and calculating the weighting matrices by the relational equation. Numerical examples are presented to show the usefulness of the proposed method.

• BMB Reports
• /
• v.45 no.8
• /
• pp.427-432
• /
• 2012

Primary cilia, single hair-like appendage on the surface of the most mammalian cells, were once considered to be vestigial cellular organelles for a past century because of their tiny structure and unknown function. Although they lack ancestral motility function of cilia or flagella, they share common ground with multiciliated motile cilia and flagella on internal structure such as microtubule based nine outer doublets nucleated from the base of mother centrioles called basal body. Making cilia, ciliogenesis, in cells depends on the cell cycle stage due to reuse of centrioles for cell division forming mitotic spindle pole (M phase) and assembling cilia from basal body (starting G1 phase and maintaining most of interphase). Ciliary assembly required two conflicting processes such as assembly and disassembly and balance between these two processes determines the length of cilia. Both process required highly conserved transport system to supply needed substance to grow tip of cilia and bring ciliary turnover product back to the base of cilia using motor protein, kinesin and dynein, and transport protein complex, IFT particles. Disruption of ciliary structure or function causes multiple human disorder called ciliopathies affecting disease of diverse ciliated tissues ranging from eye, kidney, respiratory tract and brain. Recent explosion of research on the primary cilia and their involvement on animal development and disease attracts scientific interest on how extensively the function of cilia related to specific cell physiology and signaling pathway. In this review, I introduce general features of primary cilia and recent progress in understanding of the ciliary length control and signaling pathways transduced through primary cilia in vertebrates.

• Publications of The Korean Astronomical Society
• /
• v.27 no.4
• /
• pp.149-150
• /
• 2012

We have created new catalogues of AKARI/IRC $2-24{\mu}m$ North Ecliptic Pole Deep survey through new methods of image analysis. In the new catalogues the number of false detection decreased by a factor of 10 and the number of objects detected in multiple bands increased by more than 1,500 compared to the previous work. In this proceedings the new methods of image analysis and the performance of the new catalogues are described.

• Korean Journal of Human Ecology
• /
• v.17 no.3
• /
• pp.493-500
• /
• 2008

The purposes of this study were to investigate the factors of affect induced by fashion advertising and to analyze the effects of affect on advertising effects: advertising preference, brand preference, and purchase intention. A total of 400 college students were surveyed in September, 2006, using 4 TV fashion advertisements(Bean pole, Bang bang, Nike, and Adidas). The data were analyzed with factor analysis, multiple regression analysis, ANOVA, Scheffe Test, Cronbach's $\alpha$, and path analysis, using the SPSS 12.0. The results were as follows; 1) Two factors of affect were identified: 'pleasure' and 'domination and arousal'; 2) There were differences of induced affect factors, advertising preference, brand preference, and purchase intention among 4 TV fashion advertisements; 3) Advertising preference was more affected by 'pleasure' than by 'domination and arousal'; 4) Brand preference was affected by advertising preference, 'domination and arousal' and 'pleasure' in order of significance; and 5) Purchase intention was affected by brand preference, 'domination and arousal', advertising preference, and 'pleasure' in order of significance.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.4
• /
• pp.364-370
• /
• 1990

In this paper, we propose a self-tuning PID controller for unknown systems with time-varying delay. Using pole placement equations, we derive the controller that can be extended to the multi-step time delay case. The time-varying delays are estimated by a prediction error delay method using multiple predictors. Since the order of the estimation vector is not increased, the persistant exciting condition of control input is alleviated. Since the least square method gives biased parameter estimates for colored noise cases, the recursive instrumental variable method is used to estimate system parameters. The computational burden of the proposed method is less than the conventional adaptive methods. Computer simulations are performed to illustrate the efficiency of the proposed method.