HMM-Based Transient Identification in Dynamic Process

Kwon, Kee-Choon Institute of Control 2000 Transaction on control, automation and systems eng Vol.2 No.1

In this paper, a transient identification based on a Hidden Markov Model (HMM) has been suggested and evaluated experimentally for the classification of transients in the dynamic process. The transient can be identified by its unique time dependent patterns related to the principal variables. The HMM, a double stochastic process, can be applied to transient identification which is a spatial and temporal classification problem under a statistical pattern recognition framework. The HMM is created for each transient from a set of training data by the maximum-likelihood estimation method. The transient identification is determined by calculating which model has the highest probability for the given test data. Several experimental tests have been performed with normalization methods, clustering algorithms, and a number of states in HMM. Several experimental tests have been performed including superimposing random noise, adding systematic error, and untrained transients. The proposed real-time transient identification system has many advantages, however, there are still a lot of problems that should be solved to apply to a real dynamic process. Further efforts are being made to improve the system performance and robustness to demonstrate reliability and accuracy to the required level.

Chrysosplenol C가 분리한 백서 심실 근세포 Ca2+ Transient에 미치는 효과

정석한(Suk-Han Jung),두 디 두 후옹(Do Thi Thu Huong),트란 반 성(Tran Van Sung),뉘엔 만 콩(Nguyen Manh Cuong),김영호(Young-Ho Kim),우선희(Sun-Hee Woo) 대한약학회 2011 약학회지 Vol.55 No.2

Chrysosplenol C [5,6-dihydroxy-2-(4-hydroxy-3-methoxyphenyl)-3,7-dimethoxychromen-4-one] is a flavonoid found in Miliusa balansae and Pterocaulon sphacelatum. We have recently shown that chrysosplenol C has positive inotropic effect in isolated rat ventricular myocytes. In the present study, we explored a possible mechanism for the positive inotropic effect of chrysosplenol C by examining intracellular Ca2+ transients during action potentials. The intracellular Ca2+ transients were measured by confocal Ca2+ imaging in field-stimulated single rat ventricular myocytes. Chrysosplenol C (50 μM) significantly increased the magnitudes (ΔF/F0) of Ca2+ transients (control, 1.08±0.05; chrysosplenol C, 1.25±0.03;n=8, P<0.01). Half decay time of the action potential-induced Ca2+ transient was not altered by chrysosplenol C (50 μM) (control, 154±6 ms; chrysosplenol C, 167±11 ms; n=21). The Ca2+ content in the sarcoplasmic reticulum (SR), measured as caffeine (10 mM)-induced Ca2+ transient, was significantly decreased by chrysosplenol C (50 μM). These results indicate that chrysosplenol C increases Ca2+ transients without altering Ca2+ removal kinetics in ventricular myocytes, providing a possible mechanism for its positive inotropic effect.

Jounce Bumper의 특성에 따른 과도상황 조종성능에 대한 평가 및 개선

한성제(Sung Je Han),정현욱(Hyunwook Jeong),유영선(Youngsun Yoo),원영섭(Youngsub Won),김인동(Indong Kim) 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11

Our Daily Driving condition can be divided two conditions one is steady state and the other is transient. Look at our real life driving. How many steady state driving conditions occur? There is no one can answer definitely. Most our driving conditions are transient driving in point of view by change of accelerations. But up to now vehicle dynamics simulation and test were tend to focus on steady state handling performance, So we often met difficulties in correlation steady state handling performance prediction vs. subjective driving evaluation result. To reduce this gap, we focused on transient handling Simulation and Vehicle evaluation. Hence we wrote this paper. Transients are influenced by many suspension parameters. In this paper, we select one parameter only ? Jounce bumper and we are going to discuss this part only. This paper was summarized transient handling improvement history by tuning jounce bumper stiffness and length. First all we establish evaluation guide line for what, How evaluate on transient handling conditions. And Through benchmarking test, we compared suspension performance of recent vehicles. Especially we focus on jounce bumper and we selected best in segment vehicle and we targeted that vehicle for new development vehicle. Jounce bumper tuning sample were used improve transient handling by subjective and objective test, Evaluation. So we can see potential of transient handling improvement by jounce bumper which use prevent impact force of suspension.

A Computational Model of Cytosolic and Mitochondrial [$Ca^{2+}$] in Paced Rat Ventricular Myocytes

Youm, Jae-Boum,Choi, Seong-Woo,Jang, Chang-Han,Kim, Hyoung-Kyu,Leem, Chae-Hun,Kim, Na-Ri,Han, Jin The Korean Society of Pharmacology 2011 The Korean Journal of Physiology & Pharmacology Vol.15 No.4

We carried out a series of experiment demonstrating the role of mitochondria in the cytosolic and mitochondrial $Ca^{2+}$ transients and compared the results with those from computer simulation. In rat ventricular myocytes, increasing the rate of stimulation (1~3 Hz) made both the diastolic and systolic [$Ca^{2+}]$ bigger in mitochondria as well as in cytosol. As L-type $Ca^{2+}$ channel has key influence on the amplitude of $Ca^{2+}$ -induced $Ca^{2+}$ release, the relation between stimulus frequency and the amplitude of $Ca^{2+}$ transients was examined under the low density (1/10 of control) of L-type $Ca^{2+}$ channel in model simulation, where the relation was reversed. In experiment, block of $Ca^{2+}$ uniporter on mitochondrial inner membrane significantly reduced the amplitude of mitochondrial $Ca^{2+}$ transients, while it failed to affect the cytosolic $Ca^{2+}$ transients. In computer simulation, the amplitude of cytosolic $Ca^{2+}$ transients was not affected by removal of $Ca^{2+}$ uniporter. The application of carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) known as a protonophore on mitochondrial membrane to rat ventricular myocytes gradually increased the diastolic [$Ca^{2+}$] in cytosol and eventually abolished the $Ca^{2+}$ transients, which was similarly reproduced in computer simulation. The model study suggests that the relative contribution of L-type $Ca^{2+}$ channel to total transsarcolemmal $Ca^{2+}$ flux could determine whether the cytosolic $Ca^{2+}$ transients become bigger or smaller with higher stimulus frequency. The present study also suggests that cytosolic $Ca^{2+}$ affects mitochondrial $Ca^{2+}$ in a beat-to-beat manner, however, removal of $Ca^{2+}$ influx mechanism into mitochondria does not affect the amplitude of cytosolic $Ca^{2+}$ transients.

A Computational Model of Cytosolic and Mitochondrial [Ca^(2+)] in Paced Rat Ventricular Myocytes

염재범,최성우,Chang Han Jang,김형규,Chae Hun Leem,김나리,한진 대한약리학회 2011 The Korean Journal of Physiology & Pharmacology Vol.15 No.4

We carried out a series of experiment demonstrating the role of mitochondria in the cytosolic and mitochondrial Ca^(2+) transients and compared the results with those from computer simulation. In rat ventricular myocytes, increasing the rate of stimulation (1∼3 Hz) made both the diastolic and systolic [Ca^(2+)] bigger in mitochondria as well as in cytosol. As L-type Ca^(2+) channel has key influence on the amplitude of Ca^(2+)-induced Ca^(2+) release, the relation between stimulus frequency and the amplitude of Ca^(2+) transients was examined under the low density (1/10 of control) of L-type Ca^(2+) channel in model simulation, where the relation was reversed. In experiment, block of Ca^(2+) uniporter on mitochondrial inner membrane significantly reduced the amplitude of mitochondrial Ca^(2+) transients, while it failed to affect the cytosolic Ca^(2+) transients. In computer simulation, the amplitude of cytosolic Ca^(2+) transients was not affected by removal of Ca^(2+) uniporter. The application of carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) known as a protonophore on mitochondrial membrane to rat ventricular myocytes gradually increased the diastolic [Ca^(2+)] in cytosol and eventually abolished the Ca^(2+) transients, which was similarly reproduced in computer simulation. The model study suggests that the relative contribution of L-type Ca^(2+) channel to total transsarcolemmal Ca^(2+) flux could determine whether the cytosolic Ca^(2+) transients become bigger or smaller with higher stimulus frequency. The present study also suggests that cytosolic Ca^(2+) affects mitochondrial Ca^(2+) in a beat-to-beat manner, however, removal of Ca^(2+) influx mechanism into mitochondria does not affect the amplitude of cytosolic Ca^(2+) transients.

A Computational Model of Cytosolic and Mitochondrial [Ca<SUP>2+</SUP>] in Paced Rat Ventricular Myocytes

Jae Boum Youm,Seong Woo Choi,Chang Han Jang,Hyoung Kyu Kim,Chae Hun Leem,Nari Kim,Jin Han 대한생리학회-대한약리학회 2011 The Korean Journal of Physiology & Pharmacology Vol.15 No.5

We carried out a series of experiment demonstrating the role of mitochondria in the cytosolic and mitochondrial Ca²⁺ transients and compared the results with those from computer simulation. In rat ventricular myocytes, increasing the rate of stimulation (1∼3 Hz) made both the diastolic and systolic [Ca²⁺] bigger in mitochondria as well as in cytosol. As L-type Ca²⁺ channel has key influence on the amplitude of Ca²⁺-induced Ca²⁺ release, the relation between stimulus frequency and the amplitude of Ca²⁺ transients was examined under the low density (1/10 of control) of L-type Ca²⁺ channel in model simulation, where the relation was reversed. In experiment, block of Ca²⁺ uniporter on mitochondrial inner membrane significantly reduced the amplitude of mitochondrial Ca²⁺ transients, while it failed to affect the cytosolic Ca²⁺ transients. In computer simulation, the amplitude of cytosolic Ca²⁺ transients was not affected by removal of Ca²⁺ uniporter. The application of carbonyl cyanide 4-(trifluoromethoxy) phenylhydrazone (FCCP) known as a protonophore on mitochondrial membrane to rat ventricular myocytes gradually increased the diastolic [Ca²⁺] in cytosol and eventually abolished the Ca²⁺ transients, which was similarly reproduced in computer simulation. The model study suggests that the relative contribution of L-type Ca²⁺ channel to total transsarcolemmal Ca²⁺ flux could determine whether the cytosolic Ca²⁺ transients become bigger or smaller with higher stimulus frequency. The present study also suggests that cytosolic Ca²⁺ affects mitochondrial Ca²⁺ in a beat-to-beat manner, however, removal of Ca²⁺ influx mechanism into mitochondria does not affect the amplitude of cytosolic Ca²⁺ transients.

Transient-Performance-Oriented Discrete-Time Design of Resonant Controller for Three-Phase Grid-Connected Converters

Song, Zhanfeng,Yu, Yun,Wang, Yaqi,Ma, Xiaohui The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

The use of internal-model-based linear controller, such as resonant controller, is a well-established technique for the current control of grid-connected systems. Attractive properties for resonant controllers include their two-sequence tracking ability, the simple control structure, and the reduced computational burden. However, in the case of continuous-designed resonant controller, the transient performance is inevitably degraded at a low switching frequency. Moreover, available design methods for resonant controller is not able to realize the direct design of transient performances, and the anticipated transient performance is mainly achieved through trial and error. To address these problems, the zero-order-hold (ZOH) characteristic and inherent time delay in digital control systems are considered comprehensively in the design, and a corresponding hold-equivalent discrete model of the grid-connected converter is then established. The relationship between the placement of closed-loop poles and the corresponding transient performance is comprehensively investigated to realize the direct mapping relationship between the control gain and the transient response time. For the benefit of automatic tuning and real-time adaption, analytical expressions for controller gains are derived in detail using the required transient response time and system parameters. Simulation and experimental results demonstrate the validity of the proposed method.

Fast transient response based on digital single‑cycle charge regulation (SCCR) control

Lingyun Li,Shen Xu,Limin Yu,Weifeng Sun 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.9

The Buck converter is a commonly used voltage regulator (VR) structure that supplies power to the load devices and responds to load transients. In most of the applications, the VR is controlled by voltage or current mode control, and some nonlinear approaches are used to improve the transient response which brings more complexities to the closed loop design. To achieve a fast transient response without over-regulation under a load step transient, this paper proposes a digital single-cycle regulation (SCCR) controller, which comprised a fast path, a slow path, and a neutralization path. Unlike the conventional PID control, the neutralization path of the SCCR controller is used to offset the excessive energy change in the first cycle after a load step occurs, which makes the inductor current reach its new static condition in a shorter period of time. The mathematical model of the SCCR control is established in this paper and a scanning algorithm is proposed for the design of the compensator parameters. Experimental results are presented to verify the improvement of the transient response when compared to the conventional and nonlinear PID control, the recovery time is decreased by 64.3% and 43% for load step-up and step-down when compared with nonlinear PID control.

Conditional genetic deletion of Ano1 in interstitial cells of Cajal impairs Ca²⁺ transients and slow waves in adult mouse small intestine

Malysz, John,Gibbons, Simon J.,Saravanaperumal, Siva A.,Du, Peng,Eisenman, Seth T.,Cao, Chike,Oh, Uhtaek,Saur, Dieter,Klein, Sabine,Ordog, Tamas,Farrugia, Gianrico American Physiological Society 2017 American journal of physiology, Gastrointestinal a Vol.312 No.3

<P>Myenteric plexus interstitial cells of Cajal (ICC-MY) in the small intestine are Kit(+) electrical pacemakers that express the Ano1/TMEM16A Ca2+ -activated Cl- channel, whose functions in the gastrointestinal tract remain incompletely understood. In this study, an inducible Cre-LoxP-based approach was used to advance the understanding of Ano1 in ICC-MY of adult mouse small intestine. Kit(CreERT2/+); Ano1(Fl/Fl) mice were treated with tamoxifen or vehicle, and small intestines (mucosa free) were examined. Quantitative RTPCR demonstrated similar to 50% reduction in Ano1 mRNA in intestines of conditional knockouts (cKOs) compared with vehicle-treated controls. Whole mount immunohistochemistry showed a mosaic/patchy pattern loss of Ano1 protein in ICC networks. Ca2+ transients in ICC-MY network of cKOs displayed reduced duration compared with highly synchronized controls and showed synchronized and desynchronized profiles. When matched, the rank order for Ano1 expression in Ca2+ signal imaged fields of view was as follows: vehicle controls > > > cKO(synchronized) > cKO(desynchronized). Maintenance of Ca2+ transients' synchronicity despite high loss of Ano1 indicates a large functional reserve of Ano1 in the ICC-MY network. Slow waves in cKOs displayed reduced duration and increased inter-slow-wave interval and occurred in regular-and irregular-amplitude oscillating patterns. The latter activity suggested ongoing interaction by independent interacting oscillators. Lack of slow waves and depolarization, previously reported for neonatal constitutive knockouts, were also seen. In summary, Ano1 in adults regulates gastrointestinal function by determining Ca2+ transients and electrical activity depending on the level of Ano1 expression. Partial Ano1 loss results in Ca2+ transients and slow waves displaying reduced duration, while complete and widespread absence of Ano1 in ICC-MY causes lack of slow wave and desynchronized Ca2+ transients.</P>

Digital Linear Slope Control Method for Improving the Load Transient Response of a Buck Converter

Seokwon Kim,Jong-Won Shin 전력전자학회 2023 ICPE(ISPE)논문집 Vol.2023 No.-

The paper presents digital linear slope control (LSC) method for reducing the overshoot and undershoot of the output voltage of a buck converter during the load transient. The method suppresses the output voltage fluctuation by modulating the slope of the control signal only during the load transient interval. The digital LSC method utilizes the output voltage information only. Thus, it does not require additional circuit components compared with the conventional voltage-mode control. Furthermore, the burden of microcontroller is minimized by using simple math functions such as adding and subtracting operation. A load transient detector is presented to detect a load transient. The relationship between the slope and the output voltage deviation is analyzed to validate the method. The performance of the LSC method is verified on a 15 V-5 V prototype buck converter operating at 100 kHz.