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A multifunctional magnetic catheter robot (MCR) is proposed in this article to treat occlusive vascular disease by generating steering, tunneling, and stent delivery motions. Using external magnetic fields generated by a closed-loop magnetic navigation system, the MCR can be manipulated remotely and can generate each motion by magnetic manipulation methods. The MCR has novel structures with a magnetic joint and tension springs for selective stent delivery. Constraints and a dynamic model are derived to specify the manipulation conditions for the selective treatment motions and design parameters of the MCR. Then, the MCR is prototyped, and the steering, tunneling, and stent delivery motions are verified by several experiments. Finally, an in vitro experiment with a pseudo blood clot is conducted to demonstrate the effectiveness of the MCR and its motions for the treatment of occlusive vascular disease.

Neovascularization in the retina is common pathophysiology of diabetic retinal microvasculopathy and exudative macular degeneration. Our study assessed the inhibitory activity of an ethanol‐based extract of Aucuba japonica (AJE) on abnormal angiogenesis in the retina with a hyperoxia‐induced neovascular retinopathy model. The inhibitory effects of aucubin, quercetin, and kaempferol, bioactive compounds, from A. japonica, on retinal vascular hyperpermeability were also examined. On the 7th postnatal day (P7), the C57BL/6 pups were exposed to a hyperoxic environment with 75% oxygen to develop the experimental angiogenesis in retinas. On the 12th postnatal day (P12), the pups were then returned to the normal atmospheric pressure of oxygen. From P12 to P16, the administration was intraperitoneal. The dose per day was 250 mg per kg weight. Retinal neovascularization was measured with retinal flat mounts prepared on P17. We also measured the vascular leakage mediated by the vascular endothelial growth factor (VEGF) in retinas. Mice treated with AJE had markedly smaller neovascular lesions, in comparison with vehicle‐administered mice. AJE downregulated the expression of both VEGF protein and mRNA. In addition, aucubin, quercetin, and kaempferol ameliorated VEGF‐induced retinal vascular leakage. The results of our study suggest that AJE is a potent antiangiogenic substance. AJE could also serve as a therapeutic agent for abnormal growth of vessels in the retina in patients with ischemic retinopathy. The bioactive compounds of AJE may be responsible for its antiangiogenic abilities., Aucuba japonica extract (AJE) and its bioactive compounds, aucubin, quercetin, and kaempferol, showed potent anti‐angiogenic activities in a mouse model for oxygen‐induced retinopathy. This study proposes AJE as an anti‐angiogenic functional food for patients with abnormal retinal vessel growth.

GS-E3D is an enzymatically modified ginseng extract by pectin lyase. In this study, we evaluated the preventive effects of GS-E3D on blood-retinal barrier (BRB) leakage in a rat model of diabetes. To produce diabetes, rats were injected with streptozotocin. GS-E3D was orally gavaged at 25, 50, and 100 mg/kg body weight for 6 weeks. We then compared the effect of GS-E3D with that of an unmodified ginseng extract (UGE) on retinal vascular leakage. The administration of GS-E3D significantly blocked diabetes-induced BRB breakdown. Immunofluorescence staining showed that GS-E3D reduced the loss of occludin in diabetic rats. In TUNEL staining, the number of apoptotic retinal microvascular cells was dose dependently decreased by GS-E3D treatment. GS-E3D decreased the accumulations of advanced glycation end products in the retinal vessels. In addition, the inhibition potential of GS-E3D on BRB breakage was stronger compared with UGE. These results indicate that GS-E3D could be a beneficial treatment option for preventing diabetes-induced retinal vascular injury.

EGHB010 is a standardized herbal formula of the rhizome mixture of Paeonia lactiflora Pallas and Glycyrrhiza uralensis Fisch. Neovascularization in the retina is a common pathophysiology of diabetic retinal microvasculopathy and exudative macular degeneration. In this study, we evaluated the inhibitory effects of EGHB010 on abnormal retinal angiogenesis in a hyperoxia-induced neovascular retinopathy model. Vascular endothelial growth factor (VEGF)-mediated vascular tube formation was assayed in human umbilical vascular endothelial cells (HUVECs). Experimental angiogenesis in the retinas was induced by exposing C57BL/6 pups to hyperoxic environment (75% oxygen) on postnatal day 7 (P7) and then returning them to normal oxygen pressure on P12. EGHB010 (50 and 100 mg/kg/day) was administered intraperitoneally for 5 days (P12 - P16). Retinal flat mounts were prepared to measure the extent of retinal neovascularization on P17. The incubation of HUVECs with EGHB010 (1-25 μg/mL) resulted in the inhibition of VEGF-mediated tube formation in a dose-dependent manner. EGHB010 at doses of 50 and 100 mg/kg/day inhibited the formation of retinal neovascular tufts by 31.15±2.28% and 59.83±2.92%, respectively. Together, our results indicate that EGHB010 is a potent anti-angiogenic agent and may have potential for the control of abnormal retinal vessel growth in patients with ischemic retinopathy.

We propose an untethered flexible-legged magnetic robot (FLMR) manipulated by an external rotating magnetic field (ERMF) to generate effective locomotion and precise unclogging motion to treat vascular diseases. The proposed FLMR is composed of a front body with a drill tip, a cylindrical permanent magnet, a rear body, and flexible legs. The flexible legs are obliquely attached to the bodies like blades of a propeller, so that the FLMR can generate propulsive force in a fluidic environment for locomotion and unclogging motions. To provide manipulation guidelines for locomotion and unclogging motions, we developed a dynamic model of propulsive force, axial force, and friction force, and we established a control method of propulsive force according to the rotating frequency of the ERMF and the diameter of the tube, based on the proposed dynamic model. Finally, we prototyped the FLMR and conducted several experiments to verify its navigation performances and the control method of the propulsive force. Also, we conducted an in vitro experiment with a pseudo blood clot to demonstrate the validity of the locomotion and unclogging motions of the FLMR.

We developed a crawling magnetic robot (CMR), which can stably navigate and perform biopsies remotely in tubular environments by controlling a magnetic field. The CMR is composed of a crawling part and a biopsy part. The crawling part allows the CMR to crawl forward and backward via an asymmetric friction force generated by an external precessional magnetic field. The biopsy part closes or opens the cover of a needle to use the biopsy needle selectively with the control of the external precessional magnetic field. The cover of the biopsy part prevents damage to the tubular environments because the biopsy needle is inside the cover while the CMR is navigating. We developed the design of the proposed CMR using magnetic torque constraints and a magnetic force constraint, and then we fabricated the CMR with three-dimensional printing technology. Finally, we conducted an experiment to measure the CMR’s puncturing force with a load cell and conducted an experiment in a Y-shaped watery glass tube with pseudo-tissue to verify the crawling motion, the uncovering and covering motion of the biopsy needle, and the CMR’s ability to extract tissue with the biopsy needle.

EGHB010 is a hot water extract of the rhizome mixture of Paeonia lactiflora Pallas and Glycyrrhiza uralensis Fisch. Choroidal neovascularization (CNV) and vascular leakage are the common pathophysiologies of age-related macular degeneration. In this study, we aimed to evaluate the effect of EGHB010 on retinal vascular leakage and laser-induced CNV in a rat model. Vascular endothelial growth factor- (VEGF-) induced tube formation was assayed in human retinal microvascular endothelial cells. Intravitreal VEGF-induced blood-retinal barrier breakdown was assayed in Sprague-Dawley rats. Experimental CNV was induced by laser photocoagulation in Brown Norway rats. EGHB010 (50 and 100 mg/kg/day) was administered orally for 10 days after laser photocoagulation. Choroidal flat mounts were prepared to measure the lesion size of CNV. Incubation of retinal vascular endothelial cells with EGHB010 (12.5 and 25 μg/mL) resulted in the inhibition of VEGF-induced tube formation in a dose-dependent manner. VEGF-mediated retinal vascular leakage was blocked by the oral administration of EGHB010. The CNV area was significantly lower in EGHB010-treated rats than in vehicle-treated rats. These results suggest that EGHB010 is a potent antiangiogenic agent. Thus, the oral administration of EGHB010 may have a beneficial effect in the treatment of vascular leakage and CNV in patients with age-related macular degeneration.

Advanced glycation end products (AGEs) is a causative factor of various chronic diseases, including chronic kidney disease and atherosclerosis. AGE inhibitors, such as aminoguanidine and pyridoxamine, have the therapeutic activities for reversing the increase in AGEs burden. This study evaluated the inhibitory effects of aucubin on the formation of methylglyoxal (MGO)-modified AGEs in vitro. We also determined the potential activity of aucubin in reducing the AGEs burden in the kidney, blood vessel, heart, and retina of exogenously MGO-injected rats. Aucubin inhibited the formation of MGO-modified AGE-bovine serum albumin (IC50 = 0.57 &plusmn, 0.04 mmol/L) and its cross-links to collagen (IC50 = 0.55 &plusmn, 0.02 mmol/L) in a dose-dependent manner. In addition, aucubin directly trapped MGO (IC50 = 0.22 &plusmn, 0.01 mmol/L) in vitro. In exogenous MGO-injected rats, aucubin suppressed the formation of circulating AGEs and its accumulation in various tissues. These activities of aucubin on the MGO-derived AGEs in vitro and in vivo showed its pharmacological potential for inhibiting AGEs-related various chronic diseases.

The renal accumulation of advanced glycation end products (AGEs) is a causative factor of various renal diseases, including chronic kidney disease and diabetic nephropathy. AGE inhibitors, such as aminoguanidine and pyridoxamine, have the therapeutic activities for reversing the increase in renal AGE burden. This study evaluated the inhibitory effects of ethyl pyruvate (EP) on methylglyoxal- (MGO-) modified AGE cross-links with proteins in vitro. We also determined the potential activity of EP in reducing the renal AGE burden in exogenously MGO-injected rats. EP inhibited MGO-modified AGE-bovine serum albumin (BSA) cross-links to collagen (IC50=0.19±0.03 mM) in a dose-dependent manner, and its activity was stronger than aminoguanidine (IC50=35.97±0.85 mM). In addition, EP directly trapped MGO (IC50=4.41±0.08 mM) in vitro. In exogenous MGO-injected rats, EP suppressed AGE burden and MGO-induced oxidative injury in renal tissues. These activities of EP on the MGO-mediated AGEs cross-links with protein in vitro and in vivo showed its pharmacological potential for inhibiting AGE-induced renal diseases.

Gemigliptin, a novel dipeptidyl peptidase (DPP)-4 inhibitor, is approved for use as a monotherapy or in combination therapy to treat hyperglycemia in patients with type 2 diabetes mellitus. In this study, we investigated the pharmacological profiles of gemigliptin in vitro and in vivo and compared them to those of the other DPP-4 inhibitors. Gemigliptin was a reversible and competitive inhibitor with a Ki value of 7.25±0.67nM. Similar potency was shown in plasma from humans, rats, dogs, and monkeys. The kinetics of DPP-4 inhibition by gemigliptin was characterized by a fast association and a slow dissociation rate compared to sitagliptin (fast on and fast off rate) or vildagliptin (slow on and slow off rate). In addition, gemigliptin showed at least >23,000-fold selectivity for DPP-4 over various proteases and peptidases, including DPP-8, DPP-9, and fibroblast activation protein (FAP)-α. In the rat, dog, and monkey, gemigliptin showed more potent DPP-4 inhibitory activity in vivo compared with sitagliptin. In mice and dogs, gemigliptin prevented the degradation of active glucagon-like peptide-1 by DPP-4 inhibition, which improved glucose tolerance by increasing insulin secretion and reducing glucagon secretion during an oral glucose tolerance test. The long-term anti-hyperglycemic effect of gemigliptin was evaluated in diet-induced obese mice and high-fat diet/streptozotocin-induced diabetic mice. Gemigliptin dose-dependently decreased hemoglobin A1c (HbA1c) levels and ameliorated β-cell damage. In conclusion, gemigliptin is a potent, long-acting, and highly selective DPP-4 inhibitor and can be a safe and effective drug for the long-term treatment of type 2 diabetes.

Retinal pericyte loss and neovascularization are characteristic features of diabetic retinopathy. Gemigliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor, has shown robust blood-glucose lowering effects in type 2 diabetic patients, but its effects on diabetic retinopathy have not yet been reported. We evaluated the efficacy of gemigliptin on retinal vascular leakage in db/db mice, which is an animal model for type 2 diabetes, and neovascularization in oxygen-induced retinopathy (OIR) mice, which is an animal model for ischemic proliferative retinopathy. Gemigliptin (100mg/kg/day) was orally administered to the db/db mice for 12weeks. C57BL/6 mice on postnatal day 7 (P7) were exposed to 75% hyperoxia for 5days, followed by exposure to room air from P12 to P17 to induce OIR. Gemigliptin (50mg/kg/day) was intraperitoneally injected daily from P12 to P17. Retinal neovascularization was analyzed in flat-mounted retinas on P17. We determined the efficacy and possible mechanism of gemigliptin on high glucose-induced apoptosis of primary human retinal pericytes. The oral administration of gemigliptin for 4months significantly ameliorated retinal pericyte apoptosis and vascular leakage in the db/db mice. Gemigliptin also ameliorated retinal neovascularization in the OIR mice. Gemigliptin attenuated the overexpression of plasminogen activator inhibitor-1 (PAI-1) in the retinas of diabetic and OIR mice. Gemigliptin and PAI-1 siRNA significantly inhibited pericyte apoptosis by inhibiting the overexpression of PAI-1, which is induced by high glucose. Our results suggest that gemigliptin has potent anti-angiogenic and anti-apoptotic activities via suppressing DPP-4 and PAI-1, and the results support the direct retinoprotective action of gemigliptin.

In the present study, we examined the potent retinoprotective effects of an ethanol-based extract of Aucuba japonica (AJE) and its active ingredient, aucubin, on N-methyl-N-nitrosourea (MNU)-induced retinal degeneration in mice. Retinal degeneration was induced by an intraperitoneal injection of MNU (60 mg/kg). AJE (250 mg/kg) and aucubin (15 mg/kg) were orally administered for 1 week after the MNU injection. Electroretinography (ERG) and histological examinations were performed. Retinal apoptosis and oxidative DNA damage were also quantified. The retinoprotective abilities of AJE and aucubin were also assessed in primary cultured retinal cells. Morphologically, MNU induced a remarkable decrease in the outer nuclear layer, which contains photoreceptor cells. However, this layer was well preserved in the AJE- and aucubin-administered mice. The ERG responses significantly decreased in both a- and b-wave amplitudes in the MNU-injected mice. In the AJE and aucubin-treated mice, ERG responses were significantly increased. In addition, a terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) assay and immunohistochemical staining for 8-hydroxydeoxyguanosine (8-OHdG) revealed that both AJE and aucubin attenuated MNU-induced photoreceptor cell apoptosis and oxidative DNA damage. Furthermore, the in vitro assay also showed that AJE and aucubin have potent anti-oxidative and anti-apoptotic activities in primary cultured retinal cells. These results indicate that AJE and aucubin have potent retinoprotective effects, and that this retinoprotective activity is as a result of the potency of the bioactive compound, aucubin. These pharmacological characteristics suggest the additional application of AJE or aucubin in the treatment of patients with retinal degenerative diseases.

We developed an integrated magnetic robot (IMR) that can selectively separate and assemble tethered and untethered magnetic robots. The proposed IMR is composed of a flexible-legged untethered magnetic robot (FLUMR) and a delivery catheter. Assembled magnets (AMs) with zero net magnetic moment are placed at the distal tip of the catheter and the rear part of the FLUMR. A selective separating and assembling (SSA) mechanism was proposed that can control the separating and assembling motion by an external magnetic field (EMF) to generate relative rotational movements between the catheter and FLUMR by selectively producing the attractive and repulsive forces between AMs. Finally, the IMR was prototyped to verify the SSA mechanism, and the separation, mobility, drilling, and retrieval of the developed IMR using SSA mechanism was verified in in vitro experiments.

We have proposed a novel image-based feedback control method to enhance the path-following capability for position and orientation of a magnetic catheter at its distal part. The proposed control method uses only a navigation status of the magnetic catheter for manipulation without utilizing complex analytical models. By comparing the positions of two markers of the magnetic catheter relative to a predefined path, we classify the navigation status of the magnetic catheter into four cases and determine the external magnetic field and feeding velocity according to a proposed control algorithm. Finally, we conduct a path-following experiment in an environment with multiple branches to verify the improved position and minimization of the orientation error regarding the path-following capability of the proposed control method.

We developed a magnetic catheter with enhanced steering ability of the distal end by utilizing magnets with optimized magnetization directions. The proposed magnetic catheter is composed of a flexible tube and three-ring magnets that enable the magnetic catheter to be steered by controlling external magnetic fields. We analyzed the curvature of the magnetic catheter’s distal end and the vertical displacement of the magnetic catheter’s proximal end with a mathematical model using the Euler-Bernoulli beam theory, and then determined the optimal magnetization direction of each magnet. Finally, we prototyped the magnetic catheter with optimized magnetization directions and conducted several experiments to verify its effectiveness.

This study evaluated the inhibitory effects of gemigliptin, a highly selective dipeptidyl peptidase-4 inhibitor, on the formation of advanced glycation end products (AGEs) and AGE cross-links with proteins in in vitro as well as in type 2 diabetic db/db mice. In in vitro assay, gemigliptin dose-dependently inhibited methylglyoxal-modified AGE-bovine serum albumin (BSA) formation (IC50=11.69 mM). AGE-collagen cross-linking assays showed that gemigliptin had a potent inhibitory effect (IC50=1.39 mM) on AGE-BSA cross-links to rat tail tendon collagen, and its activity was stronger than aminoguanidine (IC50=26.4 mM). In addition, gemigliptin directly trapped methylglyoxal in a concentration-dependent manner in vitro. To determine whether gemigliptin inhibits the in vivo glycation processes, gemigliptin (100 mg/kg/day) was orally administered into type 2 diabetic db/db mice for 12 weeks. Elevated serum levels of AGEs in db/db mice were suppressed by the administration of gemigliptin. These inhibitory effects of gemigliptin on the glycation process in both in vitro and in vivo suggest its therapeutic potential for ameliorating AGE-related diabetic complications.

This paper proposes a new sensorless method for a synchronous machine with an inverter integrated rotor (SMIIR). The SMIIR is a newly developed machine based on the wound rotor synchronous machine (WRSM) but has no brushes and slip-rings. The conventional high-frequency signal injection sensorless methods are based on a physical magnetic saliency. Therefore, the conventional methods cannot be applied to the SMIIR since it has no adequate physical magnetic saliency. The proposed sensorless method suggests a virtual resistance saliency created by the rotor-side inverter, of which the saliency ratio and axes can be arbitrarily set. Based on this virtual saliency, the rotor position information can be included in the relationship between the high-frequency stator voltage and stator current independent of the machine parameters or operating conditions. Because the SMIIR inherently injects a high-frequency voltage for the power transfer, there is no need to inject additional voltage for the proposed high-frequency sensorless control. The initial d-axis detection algorithm using the rotor-side inverter without magnetic saturation is also proposed. The feasibility of the proposed sensorless method was verified by the experimental results of the prototype SMIIR.

In this paper, a synchronous motor with an inverter integrated rotor (SMIIR) is introduced, and its control scheme is proposed. This presents a new breed of synchronous motor in that it integrates an inverter inside the rotor. The basic operational principle and control strategies are discussed. Given these new strategies, the SMIIR can be considered as a synchronous motor which changes its field according to the harmonic voltage of the stator inverter. The feasibility of the proposed structure of the drive system and its operation principle are evaluated through experimental results.

This paper presents a nine-phase permanent-magnet synchronous motor (PMSM) drive system based on multiple three-phase voltage source inverters. The nine-phase PMSM was developed as a traction motor for an ultrahigh-speed elevator. The mathematical model of the motor was simplified through symmetry of the system. Using the simplified model, the drive system can be controlled by the well-known d-q control theory. The feasibility and validity of the drive system were experimentally demonstrated at the world's tallest elevator test tower. Moreover, an additional experiment was performed to ensure the fault-tolerance capability of the system.

Dry eye disease is affected by a broad range of causes such as age, lifestyle, environment, medication and autoimmune diseases. These causes induce tear instability that activates immune cells and promotes expression of inflammatory molecules. In this study, we investigated the therapeutic effects of an ethanolic extract of Aucuba japonica (AJE) and its bioactive compound, aucubin, on dry eye disease. The human corneal cells were exposed to desiccation stress induced by exposing cells to air, so that viability was decreased. On the other hand, pre-treatment of AJE and aucubin restored cell survival rate depending on the dose under the dry condition. This result was confirmed again by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The mRNA expression of inflammatory molecules was reduced by the pretreatment of AJE and aucubin under the dry state. The therapeutic effects of AJE and aucubin were examined in the animal model for dry eye induced by unilateral excision of the exorbital lacrimal gland. Declined tear volumes and corneal irregularity in the dry eye group were fully recovered by the administration of AJE and aucubin. The apoptotic cells on the cornea were also decreased by AJE and aucubin. Therefore, this study suggests that administration of AJE can be a novel therapeutic for dry eye disease and that the pharmacological activities of AJE may be in part due to its bioactive compound, aucubin.

This paper presents an application of a disturbance observer for a relative position control system. In this system, since the prefixed motion profile is not defined ex ante, the acceleration state which is generated based on the profile is also not available. Therefore, feedforward acceleration controls cannot be used, and the position control performance is restricted solely by the bandwidth of the position controller. To enhance the control performance, disturbance observers can be utilized actively. The proposed method considers the position reference just as the result of a disturbance. Therefore, the relative position control can be performed by a disturbance observer as well as a position controller. As a result, the position control performance of the proposed method has been enhanced by up to 30% compared with that of the conventional method. The feasibility of the proposed method has been verified by experimental results using a high-precision linear motion control system as well as by analysis based on Bode plots.

Podocytes participate in the formation and regulation of the glomerular filtration barrier. Loss of podocytes occurs during the early stages of diabetic nephropathy and impairs glomerular filtration. Dipeptidyl peptidase-4 (DPP-4) inhibitors are widely used as anti-diabetic agents in clinical practice. In this study, we showed that gemigliptin, a novel DPP-4 inhibitor, reduced podocyte apoptosis in type 2 diabetic db/db mice without reducing hyperglycemia. Gemigliptin (100mg/kg/day) was administered orally for 12 weeks in db/db mice. Blood glucose levels and albuminuria were measured. The renal cortex was collected for histological examination, and molecular assays were used to detect 8-hydroxydeoxyguanosine, advanced oxidation protein products (AOPP), the receptor for advanced glycation end products (RAGE), and integrin-linked kinase (ILK). Type 2 diabetic db/db mice exhibited albuminuria, renal histopathological changes, and podocyte loss. Administration of gemigliptin to db/db mice suppressed albuminuria, enzyme activity and expression of DPP-4, and podocyte apoptosis. The effect of gemigliptin on diabetes-induced podocyte loss was associated with the suppression of oxidative damage, AOPP accumulation, RAGE expression, and ILK expression. These results indicate the possible benefits of using gemigliptin in diabetes patients to treat renal impairment without affecting glycemic control.

Accurate detection of the grid angle at the startup of a converter prevents the over-current trip and also reduces the commissioning time of the system. This paper presents a method to detect initial angle of the grid voltages by measuring the phase currents depending on conduction state of diodes. During the diode conduction, the source voltages are estimated and the estimated voltages are fed into phase locked loop (PLL). When all the diodes are turned off, the source voltage estimator and the PLL are bypassed and the voltage angle is calculated from the frequency of the estimated voltages. The feasibility of the proposed method has been verified by computer simulation and experimental results.

In this paper, a 9-phase Permanent Magnet (PM) synchronous motor drive system based on multiple 3-phase conventional drive systems has been proposed. A 9-phase motor has been developed as a traction motor for a world record ultra high speed elevator. The simplified mathematical model, which can be incorporated with 3-phase current controller, has been derived. The feasibility and the validity of the proposed drive system have been demonstrated by experimental results of the scaled version of a prototype 9-phase motor.

Exploiting the capability of an FPGA, a digital current controller of a single-phase inverter for grid interface is designed and implemented. A Proportional and Resonant (PR) controller realized in a parallel structure in the FPGA is used to reduce the harmonic current to ac grid. The harmonic compensators based on the PR controller are implemented up to the 19th order. The size of the LCL filter has been extremely reduced because the switching frequency is increased to 100 kHz. The validity of the FPGA based grid-connected single-phase inverter has been evaluated by experimental results.

In this paper, a motion controller based on a Field Programmable Gate Array (FPGA) with a high performance current regulator is presented. This system contains a processor and a high bandwidth current regulator as a peripheral, and all of these are implemented on a single-chip FPGA. The execution time of the current regulator is less than 200 ns at 100 MHz clock frequency. Thanks to this fast execution, the inevitable digital delay, which is 1.5 times the sampling period in a PWM inverter has been reduced to a half of the sampling period. As the result, the control bandwidth of the current regulator has been extended up to about 3 kHz at 10 kHz PWM switching frequency. By exploiting the performance of the current regulator, the speed regulation bandwidth also enhanced up to 700 Hz. The experimental results are presented to demonstrate the validity of the proposed system and the performance of the regulator.

We present a mobile augmented reality (AR) system for indoor guidance where we apply vision technique without using markers. There are two main problems: First, to augment suitable information according to users situation, it has to be identified which place the user belongs to. Second, to put information into the scene and to make it aligned with the target scene element, the basic structure of the augmenting space should be grasped. For place recognition in real time mobile system, we employ simple feature detection method combined with graph based spatial connectivity representation. Also, Image-based analysis method is applied to interpret the basic scene structure from the video.

We present a mobile augmented reality (AR) system for indoor guidance where we apply vision technique without using markers. There are two main problems: First, to augment suitable information according to user's situation, it has to be identified which place the user belongs to. Second, to put information into the scene and to make it aligned with the target scene element, the basic structure of the augmenting space should be grasped. For place recognition in real time mobile system, we employ simple feature detection method combined with graph based spatial connectivity representation. Also, image-based analysis method is applied to interpret the basic scene structure from the video.

The conventional motion control system simply consists of a PID position controller and a disturbance observer. The estimated speed from the observer has been used to control the speed as a feedback and the estimated disturbance force, which is a byproduct of the observer, has been used to reject the disturbance. However, in this case the disturbance rejection performance should be traded off with speed estimation performance. This paper explains this trade-off using Bode analysis and presents a dual observer system for the motion control application. The proposed method uses two observers, where one is dedicated to the speed estimation and the other to disturbance compensation. The disturbance rejection performance is enhanced by the custom tuned disturbance observer in the proposed method. The feasibility of the proposed method has been verified by the experimental results using a high precision linear motion control system as well as by the analysis based on Bode plot.