• The Korean Journal of Physiology and Pharmacology
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• 제26권3호
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• pp.145-155
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• 2022

Multidrug resistance of tumors has been a severe obstacle to the success of cancer chemotherapy. The study wants to investigate the reversal effects of imperatorin (IMP) on doxorubicin (DOX) resistance in K562/DOX leukemia cells, A2780/Taxol cells and in NOD/SCID mice, to explore the possible molecular mechanisms. K562/DOX and A2780/Taxol cells were treated with various concentrations of DOX and Taol with or without different concentrations of IMP, respectively. K562/DOX xenograft model was used to assess anti-tumor effect of IMP combined with DOX. MTT assay, Rhodamine 123 efflux assay, RT-PCR, and Western blot analysis were determined in vivo and in vitro. Results showed that IMP significantly enhanced the cytotoxicity of DOX and Taxol toward corresponding resistance cells. In vivo results illustrated both the tumor volume and tumor weight were significantly decreased after 2-week treatment with IMP combined with DOX compared to the DOX alone group. Western blotting and RT-PCR analyses indicated that IMP downregulated the expression of P-gp in K562/DOX xenograft tumors in NOD/SCID mice. We also evaluated glycolysis and glutamine metabolism in K562/DOX cells by measuring glucose consumption and lactate production. The results revealed that IMP could significantly reduce the glucose consumption and lactate production of K562/DOX cells. Furthermore, IMP could also remarkably repress the glutamine consumption, α-KG and ATP production of K562/DOX cells. Thus, IMP may sensitize K562/DOX cells to DOX and enhance the antitumor effect of DOX in K562/DOX xenograft tumors in NOD/SCID mice. IMP may be an adjuvant therapy to mitigate the multidrug resistance in leukemia chemotherapy.

• 한국임상약학회지
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• 제23권2호
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• pp.137-141
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• 2013

Purpose: This study compared the performance of new NONMEM estimation methods using a population analysis dataset collected from a clinical study that consisted of 40 individuals and 567 observations after a single oral dose of glimepiride. Method: The NONMEM 7.2 estimation methods tested were first-order conditional estimation with interaction (FOCEI), importance sampling (IMP), importance sampling assisted by mode a posteriori (IMPMAP), iterative two stage (ITS), stochastic approximation expectation-maximization (SAEM), and Markov chain Monte Carlo Bayesian (BAYES) using a two-compartment open model. Results: The parameters estimated by IMP, IMPMAP, ITS, SAEM, and BAYES were similar to those estimated using FOCEI, and the objective function value (OFV) for diagnosing the model criteria was significantly decreased in FOCEI, IMPMAP, SAEM, and BAYES in comparison with IMP. Parameter precision in terms of the estimated standard error was estimated precisely with FOCEI, IMP, IMPMAP, and BAYES. The run time for the model analysis was shortest with BAYES. Conclusion: In conclusion, the new estimation methods in NONMEM 7.2 performed similarly in terms of parameter estimation, but the results in terms of parameter precision and model run times using BAYES were most suitable for analyzing this dataset.

• 품질경영학회지
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• 제35권1호
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• pp.124-135
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• 2007

This study investigated the relationship between business-to-business service quality and loyalty by applying the IMP (International/Industrial Marketing and Purchasing Group) model. The study found that six dimensions of service quality which were product exchange, financial exchange, information exchange, social exchange, cooperation, and adaptation explained B2B service quality very well. More specifically, the study found that service quality dimensions of social exchange, cooperation, and adaptation were more important than those of product exchange, financial exchange, and information exchange. The study also found a positive relationship between service quality and loyalty. In fact, organizational buyers appeared to show greater loyalty as they perceived service quality better.

• Asian-Australasian Journal of Animal Sciences
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• 제16권2호
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• pp.257-260
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• 2003

A total of 135 F2 finishing pigs (65 barrows and 69 gilts) from resource population (Large White${\times}$Meishan) were slaughtered at about 87.8 kg BW. Contents of inosine acid (IMP) and carnine (HR) in muscle were assayed by HLPC and genetic parameters for IMP content and HR content were estimated using full sibs model. There was significant sex effect on IMP content(p<0.05), $3.561{\pm}0.077mg/g$ for gilt and $3.287{\pm}0.085mg/g$ for barrow. Heritability estimates for IMP and HR content were 0.127 and 0.357, respectively. The phenotypic correlation between IMP content and HR was 0.335, pH (A) 0.024, water lose rate (WLR) -0.069, intramuscular fat (IMF) -0.214, average marbling score (MARB) -0.143, average backfat measurements (AVBF) -0.084 and average color value (CV) -0.156, respectively. The result indicated that inosine acid content in meat might be retained or slightly improved by reducing backfat depth in pig breeding.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1654_1655
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• 2009

영구자석형 스테핑 모터 (Permanent Magnet Stepping Motor, PMSM)에서는 그 구조적 특징으로 인하여 필연적으로 코깅 토크 (cogging torque)가 발생한다. PMSM의 성능을 저하시키는 코깅 토크를 제거하기 위하여 Internal Model Principle (IMP)을 제안하였다. IMP를 사용하기 위해 Field-Oriented Control (FOC) 기반의 SISO 시스템을 구성하고 IMP를 PI 제어기에 병렬로 추가하였다. 모의 실험 결과로 코깅 토크로 인한 속도 리플이 효과적으로 제거됨을 보였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.837-842
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• 2007

Information storage devices using disks have a disk vibration at the frequency which is equivalent to the disk rotational speed. They also have a track vibration due to the disk eccentricity at the same frequency. In near field recording systems, the former affects the air-gap servo and the latter affects the tracking servo. In this paper, we introduce a novel control algorithm based on the internal model principle to both servos. A controller block designed by the principle is connected to the base lead-lag type compensator in parallel in order to cancel the repeatable run-out due to the disk vibration or eccentricity. Simulation and practical application of the algorithm on a near field recording system show good servo performance.

• 한국소음진동공학회논문집
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• 제17권6호
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• pp.539-546
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• 2007

Information storage devices using disks have a disk vibration at the frequency which is equivalent to the disk rotational speed. They also have a track vibration due to the disk eccentricity at the same frequency. In near field recording systems, the former affects the air-gap servo and the latter affects the tracking servo. In this paper, we introduce a novel control algorithm based on the internal model principle to both servos. A controller block designed by the principle is connected to the base lead-lag type compensator in parallel in order to cancel the repeatable run-out due to the disk vibration or eccentricity. Simulation and practical application of the algorithm on a near field recording system show good servo performance.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 춘계학술대회
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• pp.545-546
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• 2012

일반적으로 회전력이 발생하는 제어시스템에 있어서 발생되는 외란과 시스템의 동특성에 의해 발생되는 리플 등을 보정하기 위해 다양한 제어기법들이 연구되고 있다. 특히, 제어시스템에 존재하는 미지의 외란을 제거하기 위하여 AFC(Adaptive Feedforward Cancellation) 제어이론을 적용하여 미지의 외란에 대한 시스템의 안정성을 확보하려고 노력하고 있다. 그러나 기존의 AFC의 구현을 위하여 연속 시간제어시스템의 전달함수인 IMP(Internal Model Principle)를 이용하여 특정 주파수 영역에 대한 외란을 제거하고 있지만 보다 광범위한 영역에 대해서는 제어 성능은 아직 부족한 편이다. 본 논문에서는 기존의 PID 제어기를 이용한 위치제어에 있어서 발생할 수 있는 외란을 제거하기 위해 AFC 제어이론인 IMP 전달함수와 인공지능 기법인 Fuzzy 제어기를 추가로 설계하여 모터의 위치제어에 대한 성능과 외란 제어에 대한 성능을 제시하고자 한다.

• 응용통계연구
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• 제28권2호
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• pp.175-188
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• 2015

본 논문에서는 집단 약동/약력학 모형 추정을 위한 다양한 추정방법들을 이론적으로 비교, 분석하였다. 특히 확률적 표본을 이용한 방법들인 IMP, IMPMAP, SAEM 방법과 베이지안 방법의 이론적 배경과 이들의 성능을 자세히 살펴보고, 기존의 선형근사를 이용한 FO, FOCE 등의 방법과 비교 분석하였다. 확률적 표본을 이용한 추정방법들이 추정에 많은 시간이 소요된다는 문제점을 개선하기 위하여 좀 더 좋은 초기치를 찾는 방안으로 상대적으로 짧은 시간에 정확한 추정치를 계산해주는 ITS 방법을 이용하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.609-612
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• 2008

The solid immersion lens (SIL) based near-field recording (NFR) system is considered as one of the high density optical data storage system. For the NFR servo system, tracking servo control is a difficult technology to maintain extremely small gap between SIL and media within one twentieth. This is because the track pitch is decreased for increasing the recording density. In this paper, we propose disturbance observer (DOB) and internal model principle (IMP) for disturbance rejection due to eccentricity of disk. The performance of tracking controller using DOB is increased by about 85%, 94%, 97% using Q filters that have bandwidths of 50Hz, 125Hz, 250Hz, respectively. Moreover, IMP based controller is effectively reduced the residual error.