• Smart Structures and Systems
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• v.8 no.4
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• pp.367-384
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• 2011

This paper presents the design and experimental evaluation of fast output sampling feedback controller to minimize structural vibration of a cantilever beam using Shape Memory Alloy (SMA) wires as control actuators and piezoceramics as sensor and disturbance actuator. Linear dynamic models of the smart cantilever beam are obtained using online recursive least square parameter estimation. A digital control system that consists of $Simulink^{TM}$ modeling software and dSPACE DS1104 controller board is used for identification and control. The effectiveness of the controller is shown through simulation and experimentation by exciting the structure at resonance.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.5
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• pp.249-257
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• 2002

In this paper, a novel control scheme compensating source voltage unbalance and harmonic currents for the combined system of series active and shunt passive power filter is proposed, where no low/high-pass filters are used in deriving the reference voltage for compensation. The phase angle and the reference voltages compensating for harmonic current and unbalanced voltage are derived from the positive sequence component of the unbalanced voltage set, which is simply obtained by using digital all-pass filters. In order to remove the phase delay in generating the reference voltage for compensation, the reference of 5th and 7th harmonic components is predicted one-sampling ahead. The validity of the proposed scheme has been verified for 3[kVA] proto-type active power filter system.

• Proceedings of the Korean Environmental Health Society Conference
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• 2005.06a
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• pp.371-372
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• 2005

Active sampler has been widely used to measure nicotine concentration in air. The experiments were conducted to compare the active sampler method with diffusive sampler in exposure chamber and smoking areas, respectively. The result of these tests that indicated that passive sampler can be used instead of active sampler in ETS, because coefficient of determination was 0.9292 between active and passive sampling in smoking area

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.350-353
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• 1999

In this paper, a new simple control method for active power filter which can realized the complete compensation of the harmonic currents is proposed. In the proposed scheme, a compensating current reference generator employing lossless resonato implemented by a DSP(Digital Signal Processor) is introduced. Deadbeat control is employed to contro the active power filter. The switching pulse width based SVM(Space Vector Modulation) is adopted so that the current of active power filter is been exactly equal to its reference at the next sampling instant. To compensate the computation delay of digital controller, the prediction of current is achieved by the current observer with deadbeat response.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.6 no.1
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• pp.17-27
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• 1996

This study was designed to survey exposure levels of formaldehyde among workplaces in some plywood industries and to compare three sampling methods including the impinger method(IM, NIOSH method No. 3500), the solid sorbent tube method(SS, NIOSH method No. 2541), and the passive bubbler monitor method(PB, SKC). The survey was conducted in seven particle board manufacturing factories, two resin manufacturing factories and two plywood manufacturing factories in Incheon area during the period from March 6 to April 20, 1995. The workplaces included were the hot/cold press, the roller/spreader, the soaking/drying, and the reaction/mixing areas. The results were as follows; 1. The average(GM, GSD) concentrations of formaldehyde by sampling methods were 0.11(4.43) ppm by IM, 0.27(2.03) ppm by SS, and 0.29(2.04) ppm by PB, respectively. The concentrations by 1M method were statistically very significantly lower than those of SS and PB methods, particularly at low air borne concentrations of formaldehyde (p<0.001). 2. The area average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.23(2.08) ppm from the press, 0.23(1.77) ppm from the spreader, 0.24(1.51) ppm from the soaking, and 0.46(1.96) ppm from the reaction areas, respectively. The personal average concentrations of formaldehyde by workplaces measured with PB bubblers were 0.30(1.77) ppm from the press, 0.33(1.54) ppm from the spreader, 0.36(1.46) ppm from the soaking, and 0.84(1.19) ppm from the reaction areas, respectively. 3. No statistically significant differences of formaldehyde concentrations among workplaces except the reaction area(p<0.001) were found. 4. Formaldehyde concentrations from personal samples were higher than those of from area sam pies in all workplaces studied. But no statistically significant differences of formaldehyde concentrations both area and personal samples were found. In conclusion, this study found that although formaldehyde concentrations in some plywood industries in Incheon area were below the regulatory limit of 1 ppm, they were over the limits recommended by NIOSH and ACGIH. This study also suggests that the impinger method may underestimate true formaldehyde concentrations. It implies that there will be more workplaces not meeting current regulatory limit if either the solid sorbent or passive bubbler methods were used instead of the impinger method. It is suggested that passive monitors will be a reasonable alternative for area and personal sampling of formaldehyde if the accuracy and validity of passive monitors be verified before use.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.4114-4114
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• 2001

For the quality control of tablets several parameters have to be checked. The most important one is the content of an active ingredient which has to match a narrow range around the designated content. The only useful measurement mode is transmission which provides information of the complete tablet. A measurement in diffuse reflectance would register only the surface which is useless especially in case of a coated tablet. In this work tablets for a clinical study (placebo/verum studies) with very low concentrations of the active ingredient were measured. The concentration range was 0 to 6 mg with a total weight of the tablets of 105 mg, leading to a highest concentration of the active component of 5.7% by weight. Especially the spectroscopic distinction between the placebo and the low dosage forms with 0.25 and 0.5 mg active agent requires an extraordinarily accurate sampling technique. Using the VECTOR 22/N-T in transmission mode allows the collection of the information from the complete tablets. A quantitative PLS-model with transmission spectra from the tablets described above shows that the active substance can be predicted with a RMSECV (root mean square error of cross validation) of 0.04% absolute for this special application. The results are compared with those of measurements in diffuse reflectance using different accessories.

• ETRI Journal
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• v.38 no.2
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• pp.217-226
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• 2016

We propose an architecture that reduces the power consumption and active area of such a modulator through a reduction in the number of active components and a simplification of the topology. The proposed architecture reduces the power consumption and active area by reducing the number of active components and simplifying the modulator topology. A novel second-order loop filter that uses a single operational amplifier resonator reduces the number of active elements and enhances the controllability of the transfer function. A trapezoidal-shape half-delayed return-to-zero feedback DAC eliminates the loop-delay compensation circuitry and improves pulse-delay sensitivity. These simple features of the modulator allow higher frequency operation and more design flexibility. Implemented in a 130 nm CMOS technology, the prototype modulator occupies an active area of $0.098mm^2$ and consumes 5.23 mW power from a 1.2 V supply. It achieves a dynamic range of 62 dB and a peak SNDR of 60.95 dB over a 15 MHz signal bandwidth with a sampling frequency of 780 MHz. The figure-of-merit of the modulator is 191 fJ/conversion-step.

• Journal of Power Electronics
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• v.12 no.6
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• pp.895-903
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• 2012

This paper presents a fast switching direct torque control (FS-DTC) using only a single DC-link current sensor. In FS-DTC, six new active voltage complex space vectors (CSVs) are synthesized by the conventional active voltage space vectors (SVs). The corresponding sectors are rotated in the anticlockwise direction by 30 degrees. A selection table is defined to select the CSVs. Based on the "Different Phase Mode", the output sequence of the selected CSV is optimized. Accordingly, a reconstruction method is proposed to acquire the phase currents. The core of the FS-DTC is that all of the three phase currents can be reliably reconstructed during every two sampling periods, which is the result of the fast switching between different phases. The errors between the reconstructed and actual currents are strictly limited in one sampling period. The FS-DTC has the advantages of the standard DTC scheme such as simple structure, quick torque response and robustness. As can be seen in the analysis, the FS-DTC can be thought of as an equivalent standard DTC scheme with 86.6% of the maximum speed, 173.2% of the torque ripple, and 115% of the response time of the torque. Based on a dSPACE DS1103 controller, the FS-DTC is implemented in an induction machine drive system. The results verify the effectiveness of the FS-DTC.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.2
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• pp.125-134
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• 2006

This study was carried out to confirm the arguments that the role of the parents in sampling blood specimens from their children should be increased to reduce the anxiety and fear of children. The support and confidence of the parents, the reaction of the children and the subsequent action by phlebotomists should help to make an efficient sampling process for children. We randomly selected 50 children and their parents and had them fill out questionnaires before and after phlebotomy. The results were: 1. Detailed explanation by parents made children more active in sampling; 2. Higher confidence levels made parents more active in supporting children and relieving them from pain; 3. Confidence levels were higher in male children than in female children; 4. The confidence levels of parents were higher in parents of children with experience of multiple samplings and the highest level of confidence was observed in parents of children aged 61 to 120 months; 5. Only children showed the highest reaction level and very negative reactions; 6. The reaction of the phlebotomist was positive with children in good moods and negative with ones in bad moods. These results could serve as a basic tool in coping with children in phlebotomy.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.83-89
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• 2011

In the case of the tracking system with an active camera, it is very difficult to guarantee real-time processing due to the attribute of vision system which handles large amounts of data at once and has time delay to process. The reliability of the processed result is also badly influenced by the slow sampling time and uncertainty caused by the image processing. In this paper, we figure out dynamic characteristics of pixels reflected on the image plane and derive the mathematical model of the vision tracking system which includes the actuating part and the image processing part. Based on this model, we find a controller that stabilizes the system and enhances the tracking performance to track a target rapidly. The centroid is used as the position index of moving object and the DC motor in the actuating part is controlled to keep the identified centroid at the center point of the image plane.