• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.316-319
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• 1998

RPWM(Random Pulse Width Modulation) is a switching technique to spread the voltage and current harmonics on the wide frequency area. Using randomly changed switching frequency of the inverter, the power spectrum of the electromagnetic acoustic noise cab be spread to the wide-band area. The wide-band noise is much more comfortable and less annoying than the narrow-band one. So RPWM have been attracting an interest as an excellent method for the reduction of acoustic noise on the inverter drive system. In this paper a new RPPWM (Random Position PWM) is proposed and implemented. Each of three pulses is located randomly in each switching interval. Along with the randomization of PWM pulses, the space vector modulation is executed in the C167 microcontroller also. The experimental results show that the voltage and current harmonics were spread to wide band area and that the audible switching noise was reduced by proposed RPPWM method.

• 통상정보연구
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• 제9권3호
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• pp.23-32
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• 2007

The purpose of this study is to estimate and analyse the relationship between efficiency of bank industry and macroeconomic variables. We employ Johansen's multivariate cointegration methodology, since the model must be stationary to avoid the spurious results. The empirical results show that our model is stationary as well as mean-reverting. This paper also applies impulse-response functions to get additional information regarding the responses of the bank spread to the shocks economic variables such as long and short term interest rates differential, banking organ liquidity, business cycle index, and foreigner's net equity investment. The results indicate that while the bank spread respond positively to liquidity and equity investment shocks and then decay very quickly.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.11-21
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• 1992

Modern manufacturing process requires machine intelligence to meet the demands for high technology products as well as intelligence-based operating skills to lessen human worker's intervene. To meet this trend there has been wide spread interest in applying artificial neural network(ANN) to the areas of manufacturing process monitoring and control. This paper addresses application problems in such processes as welding, assembly, hydroforming process and inspection of solder joints.

• Genomics & Informatics
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• 제20권2호
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• pp.22.1-22.9
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• 2022

The rise of newer coronavirus disease 2019 (COVID-19) variants has brought a challenge to ending the spread of COVID-19. The variants have a different fatality, morbidity, and transmission rates and affect vaccine efficacy differently. Therefore, the impact of each new variant on the spread of COVID-19 is of interest to governments and scientists. Here, we proposed mathematical SEIQRDVP and SEIQRDV3P models to predict the impact of the Omicron variant on the spread of the COVID-19 situation in South Korea. SEIQEDVP considers one vaccine level at a time while SEIQRDV3P considers three vaccination levels (only one dose received, full doses received, and full doses + booster shots received) simultaneously. The omicron variant's effect was contemplated as a weighted sum of the delta and omicron variants' transmission rate and tuned using a hyperparameter k. Our models' performances were compared with common models like SEIR, SEIQR, and SEIQRDVUP using the root mean square error (RMSE). SEIQRDV3P performed better than the SEIQRDVP model. Without consideration of the variant effect, we don't see a rapid rise in COVID-19 cases and high RMSE values. But, with consideration of the omicron variant, we predicted a continuous rapid rise in COVID-19 cases until maybe herd immunity is developed in the population. Also, the RMSE value for the SEIQRDV3P model decreased by 27.4%. Therefore, modeling the impact of any new risen variant is crucial in determining the trajectory of the spread of COVID-19 and determining policies to be implemented.

• 한국통신학회논문지
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• 제34권9C호
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• pp.871-879
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• 2009

본 논문에서는 코드분할다중접속(CDMA)시스템의 기지국에 설치할 수 있는 시공간 배열 스마트안테나의 성능이 다중경로 환경의 다양한 파라미터의 변화에 어떻게 반응하는지 살펴보았다. 이 논문에서 사용된 스마트안테나는 공간분산구조로 적응배열안테나를, 시간분산구조로 다중경로의 숫자에 따른 finger 의 레이크 수신기로 구성되었으며 빔형성 방법으로 Decision Directed LMS 방법을 사용한다. 스마트안테나는 다중경로 신호의 입사각분산의 정도와 다중경로(finger)의 숫자에 민감하게 반응하는 한편 지연분산의 정도와는 거의 반응하지 않음이 컴퓨터 모의실험으로 증명되었다. 레이크 수신기의 핑거 숫자의 증가가 스마트안테나의 성능을 비선행적으로 개선시키는 효과를 수반함 역시 모의실험으로 보여졌다. 본 논문의 빔형성 과정에서 가중치벡터의 갱신은 PN상관기가 수신신호를 역확산시킨 후에 이루어진다.

• 한국벤처창업학회:학술대회논문집
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• 한국벤처창업학회 2007년도 추계학술대회
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• pp.81-109
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• 2007

정책자금의 대출금리는 기준금리에 정책목적성 스프레드와 신용위험 스프레드를 합한 것으로 결정할 수 있다. 중진공의 중산기금 대출사업은 정책목적성 중심의 저금리 대출이라는 공공성에 치우쳐져 있기 때문에 기금의 안정성과 수익성은 크게 훼손되고 있다. 중산기금이 설치목적과 공익에 맞도록 운영되더라도 기금의 안정성과 수익성이 훼손되어서는 아니 된다. 결국 중산기금 중 대출사업 관리주체인 중진공은 대출금리 설정에 있어서 최소한 기금에 손실이 발생하지 않게끔 대출금리를 설정해야 한다. 이는 정부의 정책목적성 스프레드를 현재 부(-)에서 영(0)으로 바꾸어 나가야 함을 의미한다.

• 대한두경부종양학회지
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• 제37권1호
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• pp.47-51
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• 2021

Papillary thyroid carcinoma (PTC) typically has a good prognosis, but it frequently metastasizes to the regional lymph nodes. Although survival impact of lymph node metastasis is not clear, complementary treatment is generally added after surgery when lymphatic metastasis exists. Several previous studies have reported that the multifocal PTC is associated with poor prognosis and requires selective neck dissection to prevent regional lymph node metastasis, but they are under controversy. In this study, we present a 24-year-old female patient, diagnosed as PTC with intrathyroidal spread and regional lymph node metastases. Intrathyroidal spread of PTC can only be observed microscopically and is believed to have the similar origin of unicentric multifocal PTC. As multifocal PTC is highly associated with regional lymph node metastasis and requires an additional treatment, PTC with intrathyroidal spread may follow a similar clinical course and treatment plan. Here we report the case with a brief literature review and expect its attribution to further academic interest of treatment choice.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.160-168
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• 2001

The RPWM (Random· Pulse Width Modulation) is a switching technique to spread the voltage and current harmonics over a wide frequency area. By using randomly changing switching frequency of the inverter, the power spectrum of the electromagnetic acoustic noise can be spread to the wide-band area. The wide­band noise is much more comfortable and less annoying than the narrow-band one. So, the RPWM has been attracting interest as an excellent method for the reduction of acoustic noise on the inverter drive system. In this paper a new RPPWM (Random Position Space Vector PWM) is proposed and implemented. Each of three phase pulses is located randomly in each switching interval. Along with the randomization of PWM pulses, the space vector modulation is also executed in the C167 micro-controller. The experimental results show that the voltage and current harmonics are spread to a wide band area and that the audible switching noise is reduced by the proposed RPPWM method.

• 대한물리치료과학회지
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• 제10권2호
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• pp.236-245
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• 2003

As one of the effective therapies for musculoskeletal diseases, orthopedic manual physical therapy has been watched with keen interest. In Korea, orthopedic manual physical therapy has been widely spread and applied in the field of clinical medicine since the mid-nineties. Since then, the clinical efficacy of orthopedic manual physical therapy has been approved, and orthopedic manual physical therapy has been gradually spread in the filed of clinical medicine. However, it should be noted that clinically available therapies are not well recognized. Therefore, this study was conducted to allude diagnostic and therapeutic characteristics of these therapies including deep tissue massage, manual therapy, Cyriaxs method combining manual reduction and chemotherapy, Kaltenborn-Evjenth method based on concave-convex rule for joint and soft tissue, Maitlands method based on patients sign and symptom, stress due to the posture, intraarticualr disturbance and Mckenzies method for pain due to the dysfunction.

• 대한의용생체공학회:의공학회지
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• 제15권3호
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• pp.305-316
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• 1994

All physical data in the real world are nonstationary signals that have the time varying statistical characteristics. Although few algorithms suitable to process the nonstationary signals have ever been suggested, these are treated the nonstationary signals under the assumption that the nonstationary signal is a piece-wise stationary signal. Recently, statistical analysis algorithms for the nonstationary signal have concentrated so much interest. In this paper, nonstationary EMG signals are mapped onto the orthogonal wavelet transform domain so that the eigenvalue spread of its autocorrelation matrix could be more smaller than that in the time domain. Then the model in the wavelet transform domain and an algorithm to estimate the model parameters are suggested. Also, an test signal generated by a white gaussian noise and the EMG signal are identified, and the algorithm performance is considered in the sense of the mean square error and the evaluation parameters.