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12-Bit 2차 Noise-Shaping D/A 변환기
김대정,김성준,박재진,정덕균,김원찬 대한전자공학회 1993 전자공학회논문지-A Vol.30 No.12
This paper describes a design of a multi-bit oversampling noise-shaping D/A converter which achieves a resolution of 12 bits using oversampling technique. In the architecture the essential block which determines the whole accuracy is the analog internal D/A converter, and the designed charge-integration internal D/A converter adopts a differential structure in order to minimize the reduction of the resolution due to process variation. As the proposed circuit is driven by signal clocks which contains the information of the data variation from the noise-shaping coder, it minimizes the disadvantage of a charge-integration circuit in the time axis. In order to verify the circuit, it was integrated with the active area of 950$\times$650${\mu}m^{2}$ in a double metal 1.5-$\mu$m CMOS process, and testified that it can achieve a S/N ratio of 75 dB and a S/(N+D) ratio of 60 dB for the signal bandwidth of 9.6 kHz by the measurement with a spectrum analyzer.
김대정,Song Soonseok,Sant Tonio,Demirel Yigit Kemal,Tezdogan Tahsin 대한조선학회 2022 International Journal of Naval Architecture and Oc Vol.14 No.1
The loss of ship propulsion has been reported to be the most frequent cause of accidents at sea over the last few years. The loss of propulsive power has a notable effect on the behaviour of a ship during ship manoeuvring, and hence the manoeuvrability of ships suffering from propulsion loss should be accurately estimated for navigation safety. The aim of this study is to evaluate the effects of a propulsion failure on the manoeuvrability of the KRISO Container Ship (KCS) using a fully nonlinear URANS model, which is capable of resolving complex fluid-structure interactions with high accuracy. A series of case studies were carried out to compare the ship performances of both the normal and propulsion loss condition, especially for the course keeping and turning circle manoeuvres. The results explicitly revealed that the propulsion failure has a strong influence on the ship manoeuvrability, implying the importance of sufficient propulsion power when vessels are underway. The key findings obtained from this study are believed to provide navigators with a practical insight into ship manoeuvrability under the propulsion failure condition as well as contribute to developing standards for navigational safety in waves.
심방세동이 동반된 비후성 심근증 환자에서 아미오다론 유발성 다장기 독성 1예
김대정,이상칠,박기수,김경중,황원태,이창수,이무현,한대희,고현철 대한노인병학회 2013 Annals of geriatric medicine and research Vol.17 No.4
Amiodarone is an antiarrhythmic drug known to have adverse effects on multiple organs. Most studies have reported the side effects of the drug, which may result from rapid administrations or from long-term, high dosage administrations. However, toxicity issues have also been reported from patients administered with low doses of the drug for a long period of time. Here we report a case of an 82-year-old female who had shown symptoms and signs of pulmonary, hepatic, and neurotoxicity after taking amiodarone for 14 months in order to treat her atrial fibrillation without regular outpatient follow-up. We highlight the importance of the recommended evaluations, including lung, liver, and thyroid functions, as well as the neurological examinations in patients treated with amiodarone for a long period of time during regular follow-up.