• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.871-876
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• 2011

In this paper, a voltage-controlled frequency tunable current-mode integrator and a 3rd-order current-mode Chebyshev filter in 1.8V-$0.18{\mu}m$ CMOS is realized for software radio applications in system-on-chips. This filter is used for reconstruction purposes between a current-steering DAC and a current-mode mixer. Power consumption of the designed filter can be reduced by using a current-mode small size integrator. And also, cutoff frequency of this filter is variable between 1.2MHz and 10.1MHz, the power consumption is 2.85mW. And the voltage bias compensated circuit is used to control the voltage variation.in the designed filter.

• Archives of Plastic Surgery
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• v.49 no.6
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• pp.716-723
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• 2022

Background In March 2021, the United States Food and Drug Administration (FDA) safety communication cautioned against the use of acellular dermal matrix (ADM) products in breast reconstruction and reiterated that the FDA does not approve ADM use in breast surgery. This study aims to assess the safety of ADM use in breast reconstruction. Methods Women who underwent ADM and non-ADM assisted tissue expander (TE)-based breast reconstruction were identified using the National Surgical Quality Improvement Program database (2012-2019). Trends of ADM use over time, and 30-day outcomes of surgical site infection (SSI), dehiscence, and unplanned reoperation were assessed. Results Of the 49,049 TE-based breast reconstructive cases, 42.4% were ADM assisted and 57.6% non-ADM assisted. From 2012 to 2019, the use of ADM increased from 26.1 to 55.6% (relative risk [RR] =1.10; p < 0.01). Higher rates of SSI (3.9 vs. 3.4%; p = 0.003) and reoperation (7.4 vs. 6.0%; p < 0.001) were seen in the ADM cohort. There was no significant difference seen in dehiscence rates (0.7 vs. 0.7%; p = 0.73). The most common reoperation within 30 days for the ADM group (17.6%) was removal of TE without insertion of implant (current procedural terminology: 11,971). ADM-assisted breast reconstruction was associated with increased relative risk of SSI by 10% (RR = 1.10, confidence interval [CI]: 1.01-1.21; p = 0.03) and reoperation by 15% (RR = 1.15, CI: 1.08-1.23; p < 0.001). Conclusions ADM-assisted breast reconstruction more than doubled from 2012 to 2019. There are statistically higher complication rates of SSI (0.5%) and reoperation (1.4%) with ADM use in TE-based breast reconstruction, suggesting that reconstruction without ADM is safe when comparing immediate postoperative outcomes.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.6
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• pp.592-600
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• 2000

In this paper, a novel control scheme of three-phase PWM rectifiers using only dc-side sensors is proposed. The phase currents are reconstructed from switching states of the rectifier and the dc output current. For effective current control, the currents are estimated by a predictive state observer. Also, both the phase angle and the magnitude of the source voltage are estimated by controlling the deviation between the model current and the system current to be zero. The validity of the proposed ac phase and current sensorless technique has been verified by experimental results.

• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.54-55
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• 2013

본 논문은 병렬 삼상 부스트 컨버터에서 2개의 DC-link 전류 센서를 이용한 새로운 방법을 제안 하였다. 단 2개의 전류 센서만 이용하였고, 순환 전류 문제를 해결하면서 전류를 재구성을 하였다. 이러한 병렬 삼상 부스트 컨버터는 저가 및 중, 대형 전력 시스템에 많이 사용될 것이다. 제안한 방법을 적용하고 그 타당성을 시뮬레이션으로 검증 하였다.

• Archives of Plastic Surgery
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• v.43 no.6
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• pp.523-528
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• 2016

Background The use of acellular dermal matrix (ADM) in implant-based immediate breast reconstruction has been increasing. The current ADMs available for breast reconstruction are offered as aseptic or sterile. No published studies have compared aseptic and sterile ADM in implant-based immediate breast reconstruction. The authors performed a retrospective study to evaluate the outcomes of aseptic versus sterile ADM in implant-based immediate breast reconstruction. Methods Implant-based immediate breast reconstructions with ADM conducted between April 2013 and January 2016 were included. The patients were divided into 2 groups: the aseptic ADM (AlloDerm) group and the sterile ADM (MegaDerm) group. Archived records were reviewed for demographic data and postoperative complication types and frequencies. The complications included were infection, flap necrosis, capsular contracture, seroma, hematoma, and explantation for any cause. Results Twenty patients were reconstructed with aseptic ADM, and 68 patients with sterile ADM. Rates of infection (15.0% vs. 10.3%), flap necrosis (5.0% vs. 7.4%), capsular contracture (20.0% vs. 14.7%), seroma (10.0% vs. 14.7%), hematoma (0% vs. 1.5%), and explantation (10.0% vs. 8.8%) were not significantly different in the 2 groups. Conclusions Sterile ADM did not provide better results regarding infectious complications than aseptic ADM in implant-based immediate breast reconstruction.

• Archives of Plastic Surgery
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• v.51 no.2
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• pp.156-162
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• 2024

Background Perioperative management in autologous breast reconstruction has gained focus in recent years. This study compares two pain management protocols in patients undergoing abdominal-based free flap breast reconstruction: a past protocol (PP) and a current protocol (CP)-both intended to reduce opioid consumption postoperatively. The PP entails use of a pain catheter in the abdominal wound and the CP consists of an intraoperative nerve block in addition to refinements in the oral pain management. We hypothesize that the CP reduces opioid consumption compared to PP. Methods From December 2017 to January 2020, 102 patients underwent breast reconstruction with an abdominal-based free flap. Two postoperative pain management strategies were used during the period; from December 2017 to September 2018, the PP was used which entailed the use of a pain catheter with ropivacaine applied in the abdominal wound with continuous distribution postoperatively in addition to paracetamol orally and oxycodone orally pro re nata (PRN). From October 2018 to January 2020, the CP was used. This protocol included a combination of intraoperative subfascial nerve block and a postoperative oral pain management regime that consisted of paracetamol, celecoxib, and gabapentin as well as oxycodone PRN. Results The CP group (n = 63) had lower opioid consumption compared to the PP group (n = 39) when examining all aspects of opioid consumption, including daily opioid usage in morphine milligram equivalents and total opioid usage during the stay (p < 0.001). The CP group had shorter length of hospital stay (LOS). Conclusion Introduction of the CP reduced opioid use and LOS was shorter.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.211-212
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• 2012

This paper proposes a single current sensor control technique for controlling motors that use only a single DC-Link current sensing resistor to obtain the information of three line currents. However, the measurement is distorted due to the too narrow current pulse width in the shunt resistor. To solve this problem, the existing phase current reconstruction methods are voltage split methods. They have a disadvantage which makes noise. A new dedicated observer is applied to decrease noise problem. Experimental results showed the effectiveness of the proposed method.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.1-9
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• 2023

For optimal image quality of computer tomography angiography (CTA), different iodine concentrations and scan parameters were applied to quantitatively evaluate the image quality characteristics of filtered back projection (FBP), hybrid-iterative reconstruction (hybrid-IR), and deep learning reconstruction (DLR). A 320-row-detector CT scanner scanned a phantom with various iodine concentrations (1.2, 2.9, 4.9, 6.9, 10.4, 14.3, 18.4, and 25.9 mg/mL) located at the edge of a cylindrical water phantom with a diameter of 19 cm. Data obtained using each reconstruction technique was analyzed through noise, coefficient of variation (COV), and root mean square error (RMSE). As the iodine concentration increased, the CT number value increased, but the noise change did not show any special characteristics. COV decreased with increasing iodine concentration for FBP, adaptive iterative dose reduction (AIDR) 3D, and advanced intelligent clear-IQ engine (AiCE) at various tube voltages and tube currents. In addition, when the iodine concentration was low, there was a slight difference in COV between the reconstitution techniques, but there was little difference as the iodine concentration increased. AiCE showed the characteristic that RMSE decreased as the iodine concentration increased but rather increased after a specific concentration (4.9 mg/mL). Therefore, the user will have to consider the characteristics of scan parameters such as tube current and tube voltage as well as iodine concentration according to the reconstruction technique for optimal CTA image acquisition.

• Journal of the Korean Orthopaedic Association
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• v.55 no.4
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• pp.294-304
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• 2020

Anterior cruciate ligament (ACL) reconstruction is a successful procedure independently by patient selection, timing of surgery, surgical technique, choice of graft, and fixation methods. Among these factors, graft selection and fixation methods might be the most critical yet controversial questions for surgeons. Although recent studies showed that grafts have advantages and drawbacks, there is still no ideal graft. Similarly, many fixation methods of femoral and tibial tunnels have been proposed over the last few decades, with no clear superiority of one technique over another. Surgeons should be familiar with a variety of grafts, fixation techniques, and their specific associated surgical procedures as well as the advantages and disadvantages of each. Therefore, this article summarizes the current literature and discusses the current state of graft selection and fixation methods in the treatment of an ACL injury.

• The Transactions of the Korean Institute of Power Electronics
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• v.21 no.4
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• pp.343-350
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• 2016

Generally, the average phase current is sampled at the midpoint of a PWM signal for the vector control of an AC motor. The three-phase current can also be reconstructed from a DC-link shunt resistor by sampling the shunt voltage during the active vectors of the SVPWM. However, the reconstructed current is different from the average current because of the deviation of the sampling point from the midpoint of the PWM signal. This paper proposes an algorithm to estimate the average current from the reconstructed current in a single-shunt inverter. The proposed method is derived from the phase current slopes based on switching states and corresponding switching time. In addition, the proposed method is generalized for all the six sectors of the space vector hexagon. The validity of the proposed algorithm is verified with simulations and experiments.