• Journal of Industrial Technology
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• v.20 no.B
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• pp.201-206
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• 2000

A priori information of object is needed to control in some well known control methods. But we can't always know a priori information of object in real world. In this paper, the inverted pendulum is simulated as a control task with the goal of learning to balance the pendulum with no a priori information using neural network controller. In contrast to other applications of neural networks to the inverted pendulum task, the performance feedback is unavailable on each training step, appearing only as a failure signal when the pendulum falls or reaches the bound of track. To solve this task, the delayed performance evaluation and the learning of nonlinear of nonlinear functions must be dealt. Reinforcement learning method is used for those issues.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.218-219
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• 2013

In this paper, an improved modulated carrier control for a single-phase shunt active power filter(SAPF), which eliminates harmonic currents at the ac main drawn by nonlinear loads, is introduced. In contrast to conventional methods, since this control method does not need to generate a current reference for SAPF, only the ac main current is sensed instead of the load current and SAPF current. With the proposed control method, the ac main current is directly controlled to be sinusoidal and in phase with the supplied ac voltage by simply comparing the modulated carrier signal with the ac main current. The operation of the proposed SAPF is analyzed and simulation results verify its performance.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1642-1643
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• 2007

In this paper, we design a terminal sliding mode controller for chaotic nonlinear systems. Terminal sliding mode control (TSMC) method can drive the tracking errors to zero within finite time. In addition, TSMC has the advantages such as improved the performance, the robustness, the reliability and the precision by contrast with classical sliding mode control (CSMC). Besides, we can obtain the final time using general formula. Finally, we carry out simulations of some examples, such as Duffing and Lorenz systems, to illustrate the effectiveness of the proposed control.

• Journal of Technology Innovation
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• v.11 no.1
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• pp.177-193
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• 2003

This paper examines empirically if the increase of funding uncertainty in government supported R&D institutes(GSRIs) in Korean cause managers to use more effective management control practices. Recently government introduced a new government R&D budget management system, based on competition, named PBS(Project Base System). Government requires GSRIs to be self-supporting and compete for funding from government. The introduction of new budget management system named PBS, has resulted in the increase of funding uncertainty in GSRIs. According to institutional theory, government organizations gain legitimacy by conforming to external expectations regarding management control practices, In contrast, contingency theory proposes that management control practices are driven by the fit between the technical features of the environment and the management control practices. The contingency literature provides that one external factor expected to motivate government managers to use more efficient control practices is the presence of competition and funding uncertainty. This paper use both theoretical perspective to develop hypotheses and examine the influence of funding environment on management control practices. Results show that the more institutionalized environment, the more managers in GSRIs rely on bureaucratic mode of control for conforming to external requirements, and the greater the funding uncertainty, the more managers use results and personal modes of control to improve research team performance.

• Transactions on Control, Automation and Systems Engineering
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• v.1 no.2
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• pp.94-98
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• 1999

Optical scanning systems use glavanometers to point the laser beam to the desired position on the workpiece. The angular speed of a galvanometer is typically controlled using Proportional+Integral+Derivative(PID) control algorithms. However, natural variations in the dynamics of different galvanometers due to manufacturing, aging, and environmental factors(i.e., process uncertainty) impose a hard limit on the bandwidth of the galvanometer control system. In general, the control bandwidth translates directly into efficiency of the system response. Since the optical scanning system must have rapid response, the higher control bandwidth is required. Auto-tuning PID algorithms have been accepted in this area since they could overcome some of the problems related to process uncertainty. However, when the galvanometer is attached to a larger mechanical system, the combined dynamics often exhibit resonances. It is well understood that PId algorithms may not have the capacity to increase the control bandwidth in the face of such resonances. This paper compares the achieable performance and robustness of a galvanometer control system using a PID controller tuned by the Ziegler-Nichols method and a controller designed by the Quantitative Feedback Theory(QFT) method. The results clearly indicate that-in contrast to PID designs-QFT can deliver a single, fixed controller which will supply high bandwidth design even when the dynamics is uncertain and includes mechanical resonances.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.472-475
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• 2008

Generally, a linear vibration theory regards a vibratory system as the superposition of many degrees of vibratory system. Modal analysis stems, in fact, considers the vibration system as what has input, output, and transfer function that relates the input and output. When we want to control, however, the vibratory system, we define, first, the object function that can be vibration energy of certain vibratory system. Then, we try to find the transfer function that can minimize the object function. We can readily extend this approach to control the distributed vibration system. For example, the vibrations of a vehicle, including ships and trains. In this case, we may want to minimize the vibration of the area we select. For example, minimize the vibration of the passengers' seat, but allowing the vibration of other area; for example engines and wheels. This paper introduces a general theory that can control the vibration of the selected area, which can be called as "regional control of vibration." In fact, this is the extended theory of well known sound control of "bright zone"(Choi and Kim, 2002).]. Several illustrative examples demonstrate the applicability and properties that are not available if we use modal analysis method.

• Journal of Korean Neurosurgical Society
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• v.60 no.2
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• pp.250-256
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• 2017

Objective : Cases of a ruptured pericallosal artery aneurysm with a high risk of intraoperative premature rupture and technical difficulties for proximal vascular control require a technique for the early and safe establishment of proximal vascular control. Methods : A combined pterional or subfrontal approach exposes the bilateral A1 segments or the origin of the ipsilateral A2 segment of the anterior cerebral artery (ACA) for proximal vascular control. Proximal control far from the ruptured aneurysm facilitates tentative clipping of the rupture point of the aneurysm without a catastrophic premature rupture. The proximal control is then switched to the pericallosal artery just proximal to the aneurysm and its intermittent clipping facilitates complete aneurysm dissection and neck clipping. Results : Three such cases are reported : a ruptured pericallosal artery aneurysm with a contained leak of the contrast from the proximal side of the aneurysm, a low-lying ruptured pericallosal artery aneurysm with irregularities on its proximal wall, and a multilobulated ruptured pericallosal artery aneurysm with the parasagittal bridging veins hindering surgical access to the proximal parent artery. In each case, the proposed combined pterional-interhemispheric or subfrontal-interhemispheric approach was successfully performed to establish proximal vascular control far from the ruptured aneurysm and facilitated aneurysm clipping via the interhemispheric approach. Conclusion : When using an anterior interhemispheric approach for a ruptured pericallosal artery aneurysm with a high risk of premature rupture, a pterional or subfrontal approach can be combined to establish early proximal vascular control at the bilateral A1 segments or the origin of the A2 segment.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.405-410
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• 2004

The effect of treatment with Citrus junos fractions (citron 3W, citron 3H, citron 4W and citron 4H) upon rat hepatocytes exposed to alcohol was investigated. We compared the serum biochemistry of rats administered both alcohol and Citrus junos fractions to control rats treated with alcohol alone. The effects of Alanine amino transferase (ALT) were significantly lower in the citron 3H extract group compared with the negative control group (p<0.05) and other experimental groups were not significantly low but a little low compared to negative control group. The levels of triglyceride (TG) were significantly low in all experimental groups compared with negative control group. Especially triglyceride level of citron 3H was lowest near to normal control group. The concentration of total cholesterol was significantly high in negative groups compared with normal control group but in all experimental groups, the concentration of total cholesterol was similar to that of negative control group. Total cholesterol of the citron 4W group was somewhat low compared with negative control group. In contrast, activities of alcohol dehydrogenase (ADH) were significantly higher in all experimental groups compared with the negative control (p<0.05) group. These data suggest that Citrus junos fractions may represents an excellent candidate for protection of rat hepatocytes from alcohol-mediated damage.

• Journal of Environmental Science International
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• v.14 no.3
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• pp.345-350
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• 2005

Three-week old Commelina communis was transferred and grown in Hoagland solution containing $100{\mu}M\;Cd^{2+},\;100{\mu}M\;Cd^{2+}+100{\mu}M\;kinetin,\;100{\mu}M\;Cd^{2+}+100{\mu}M\;zeatin\;and\;100{\mu}M\;Cd^{2+},\;200{\mu}M$ zeatin for 7 days, and then a number of physiological activities were investigated. In control, the length of the stem of plants was increased to 4.7cm, but in $Cd^{2+},\;Cd^{2+}+kinetin,\; Cd^{2+}+100{\mu}M\;zeatin\;and\;Cd^{2+}+200{\mu}M$ zeatin treatments, the growth of plants were increased to 1.5cm, 2.1cm, 3.9cm and 4.3 em, respectively. In the treatments of $Cd^{2+},\;Cd^{2+}+kinetin,\;Cd^{2+}+100{\mu}M\;zeatin\;and\; Cd^{2+}+200{\mu}M$ zeatin, total chlorophyll contents were reduced to $26\%,\;24\%,\;15\%\;and\;3\%$, respectively, on the contrast to the control. In chlorophyll fluorescence experiments, Fv/Fm ratios were also reduced to $44\%,\;21\%,\;17\%\;and\;5\%$ in the light intensity of $2100{\mu}Mmole\;E\;m^{-2}s^{-1}\;by\;Cd^{2+},\;Cd^{2+}+kinetin,\;Cd^{2+}+$100{\mu}M\;zeatin\;and\;Cd^{2+}+200{\mu}M$ zeatin treatments on the contrast to the control. Water stresses were increased to 2.6, 1.7 and 1.2 times by $Cd^{2+},\; Cd^{2+}+kinetin\;and\;Cd^{2+}+{\mu}M$ zeatin. On the other hand, combination of $Cd^{2+}+200{\mu}M$ zeatin reduced water stress to $0.12\%$. In $Cd^{2+}$ accumulation experiments $Cd^{2+}$transports were inhibited to $33\%\; 48\%\;and\;70\%\;by\;Cd^{2+}+kinetin,\;Cd^{2+}+100{\mu}M\;zeatin\;and\;Cd^{2+}+200{\mu}M$ zeatin. Therefore, it could be concluded that zeatin clearly reduced the toxicities of $Cd^{2+}$ by reducing the absorption of $Cd^{2+}$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.592-595
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• 2008

This paper presents development of automatic image quality register optimization system using mobile TFT-LCD (Thin Film Transistor-Liquid Crystal Display) driver IC and embedded software. It optimizes automatically gamma adjustment and voltage setting registers in mobile TFT-LCD driver IC to improve gamma correction error, adjusting time, flicker noise and contrast ratio. Developed algorithms and embedded software are generally applicable for most of the TFT-LCD modules. The proposed optimization system contains module-under-test (MUT, TFT-LCD module), control program, multimedia display tester for measuring luminance, flicker noise and contrast ratio, and control board for interface between PC and TFT-LCD module. The control board is designed with DSP and FPGA, and it supports various interfaces such as RGB and CPU.