• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 19-21 Oct. 1992
• /
• pp.419-424
• /
• 1992

A robust nonlinear predictive control strategy using a disturbance estimator is presented. The disturbance estimator is comprised of two parts: one is the disturbance model parameter adaptation and the other is future disturbance prediction. RLSM(recurrsive least square method) with a forgetting factor is used to de the uncertain distance model parameters and for the future disturbance prediction, future process outputs and inputs projected by the process model are used. The simulation results for chemical reactors indicate that a substantial improvement in nonlinear predictive control performance is possible using the disturbance estimator.

• 전력전자학회논문지
• /
• 제21권1호
• /
• pp.80-87
• /
• 2016

This study investigates output voltage variation of a voltage disturbance generator in case of sag and swell modes. The generator uses series transformers and silicon-controlled rectifier thyristors to provide voltage disturbance; consequently, voltage drop at the output terminal is inevitable. On the basis of the analysis, voltage drop increases as the power factor decreases in lagging. Voltage drop is 3.7 [%] at a power factor (lagging) of 0.8. Simulation and experimental results show the validity of the analysis.

• 제어로봇시스템학회논문지
• /
• 제14권2호
• /
• pp.105-110
• /
• 2008

This paper presents a control method to maintain stable mold level for unsteady bulging in high speed casting. The stabilizing mold level is an important factor to get high quality products. But, for various reasons, there are several disturbance factors which make mold level unstable. Bulging is one of disturbance factors and considered for the current stage of study. We design a disturbance observer to attenuate the effect of bulging which is periodic mold level disturbance. Since the period of bulging varies with the casting speed, the parameters of disturbance observer are changed by the casting speed. Simulation is illustrated to demonstrate stable performance of the proposed method in comparison with a previous method in a variable operating frequency.

• 대한간호학회지
• /
• 제27권1호
• /
• pp.178-188
• /
• 1997

As a descriptive survey, this study was attempted to get basic data necessary to recognize the factors that disturb the therapeutic atmosphere of hospital wards as perceived by nurses and hospitalized patients, to identify differences between the perceptions of the nurses and of patients. The subjects, 159 patients in Pusan National Hospital and 68 nurses working there were sampled between March 18 and April 13, 1996. The tool used to measure the disturbing factors was an amended form of the one developed by Kim, Mae Ja(1983). The differences between each subject's score for each factor were analyzed using means & SD. and the highest 3 items above the mean score for each factor were collected and compared. The results are described below : 1. Subject's perception of main disturbing factors : patients reported that the main factors were 'loss of role & economic trouble', 'the prognosis of disease', 'the change of daily life' but nurses replied that the main factors were' the prognosis of disease', 'the communication trouble with the medical team & interpersonal relationships'. 'The change of daily life' was not a perceved factor by nurses, but ranked third by the patients. 2. Subject's perception degree of each disturbing factor : (1) among the items related to interpersonal relationship. the patient group reported that the worst disturbance was dur to severely ill patients in the same room' but the nurse group regarded 'greed to monopolize wheelchairs or other supplies' as the worst disturbance. (2) among the items related to physical factors. the patient group regarded 'limitations to wash their body, physical pain and limitations in physical activity' as the worst disturbance, but the nurse group regarded' physical pain', and 'limitations to activity or change of appearance' as the worst disturbance. (3) among the items related to the change of daily activity, the patient group regarded 'the boredom of hospitalization or infavorable diet' as the worst disturbance, but the nurse group regarded 'too much noise or unclean room' as the worst disturbance. (4) among the items related to the communication trouble with medical team, the patient group regarded 'the ignorance of their disease due to poor information. the inability to understand the language of the medical team or the difficulty in seeing physician in time' as the worst disturbance, but the nurse group regarded 'the inability to trust physicians and physician's poor attention to patients' as the worst disturbance.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2006년 학술대회 논문집 정보 및 제어부문
• /
• pp.187-189
• /
• 2006

In mechanical system, gear trains have backlash innately. With the presence of inherent backlash, the overall system performance is limited in many practical control systems. It has been reported that a disturbance observer has the property of effective removing disturbance and cutting measurement noise off. The plant is remodeled with modified disturbance observer to observe and compensate backlash characteristics. And this paper describes a method to design Q filter and to analyze the effects of disturbance and measurement noise to the output. It is shown that the vibration and tracking error caused by backlash were decreased and the time constant and relative degree are important factor to design Q filter.

• Journal of Ecology and Environment
• /
• 제33권3호
• /
• pp.205-216
• /
• 2010

This research identified a disturbance regime caused by wild boar in a mature Quercus mongolica forest and analyzed the impact of this disturbance on the structure and distribution of herbaceous plants in Mt. Jeombong, Korea. We demonstrate that disturbance by wild boar was most frequent from winter to early spring, but also occurred year round. Areas which were frequently disturbed by wild boar included the mountain ridge, the mild slope on the north face, and sites with high concentration of Erythronium japonicum. The disturbance cycle by the wild boar in this region was estimated at approximately 2.8 years. The wild boar's reduced the community's species diversity and herbaceous coverage, and increased its evenness. This disturbance reduced the coverage of spring ephemeral; Veratrum nigrum var. ussuriense, Symplocarpus niponnicus, Anemone koraiensis and Corydalis turtschaninovii were particularly sensitive. In addition, summer green herbaceous plants such as Astilbe chinensis, Ainsliaea acerifolia, Meehania urticifolia, and Pimpinella brachycarpa were sensitive to the wild boar's. It was found that wild boar ate E. japonicum most selectively of all plants in this investigation area. In conclusion, together with micro-topography, wind, formation of gaps of a forest and rearrangement of litter layer, wild boar's disturbance is an important factor influencing the dynamic changes of an herbaceous community in a mature temperate hardwood forest.

• 종양간호연구
• /
• 제12권2호
• /
• pp.117-124
• /
• 2012

Purpose: The purpose of this study was to assess pain, sleep disturbance, fatigue, and the quality of life and to identify the impact of pain, sleep disturbance and fatigue on the quality of life in patients with pancreatic cancer undergoing chemotherapy. Methods: Data were collected from June to July, 2010. Participants were recruited from Y university hospital in Seoul. Research instruments included numeric rating scale for pain, Functional Assessment Chronic Illness Therapy-Functional Well-Being (FACIT-FWB): General Factor 5 (GF5) for sleep disturbance, Functional Assessment of Cancer Therapy-General (FACT-G) for quality of life, and FACT-Fatigue for fatigue. Results: The quality of life for cancer patients had a significant relationship with pain, sleep disturbance, and fatigue. The significant factors influencing quality of life were pain, sleep disturbance, and fatigue that explained 52.6% of the variance. Conclusion: Patients with pancreatic cancer undergoing chemotherapy experienced pain, fatigue, and sleep disturbance which led to a negative effect on quality of life. The results suggest that intervention program to improve quality of life could reduce pain, fatigue, and sleep disturbance of pancreatic cancer patients undergoing chemotherapy.

• 한국자동차공학회논문집
• /
• 제5권6호
• /
• pp.53-63
• /
• 1997

This study examines the influence of some dimensional errors on the shudder-type disturbance of the tripod joint and vehicle, using an experimental evaluation and related simulation. With the introduction of the concept of influence factor, the sensitivities of shudder-type disturbance can be evaluated as the ratio of the difference between the ideal value without dimensional errors and actual value with them in the tripod joint and vehicle. Futhermore, influence factors calculated in this study can be utilized as a basic design data for the practical application of the tripod joint to an automobile design.

• 전력전자학회논문지
• /
• 제15권5호
• /
• pp.411-416
• /
• 2010

본 논문에서는 변압기 기반 전압변동 발생기의 직렬변압기에 의한 전압강하 특성을 분석하였다. 전압변동 발생기의 회로구성 방식에는 여러 가지가 있으나 본 논문에서는 비교적 비용이 저렴하고 신뢰도가 높은 직렬변압기를 사용한 방식에 대해 다루고자 한다. 직렬변압기에 의한 전압강하는 변압기의 %Z와 부하용량 및 부하역률에 의해 결정된다. 직렬변압기의 설계가 잘못되면 전압강하가 심각하게 발생하여 제대로 된 성능을 확보할 수 없다. 본 논문에서는 10kVA급 전압변동 발생기에 대해 %Z가 4%인 직렬변압기를 사용한 경우 부하역률에 따른 전압강하를 분석하였으며 지상 부하일수록 전압강하가 증가하고 역률이 0.85 지상인 경우 전압강하가 4% 발생함을 시뮬레이션 및 실험을 통하여 확인하였다.

• 제어로봇시스템학회논문지
• /
• 제9권6호
• /
• pp.425-434
• /
• 2003

The disturbance observer(DOB) has been widely used in high speed and high precision motion control applications and the characteristics of DOB have been investigated in depth. Though most of DOB's have been implemented as the discrete-time form in digital devices, we are still short of the researches on discrete-time DOB (DDOB) in spite of rich references on continuous-time DOB. In this paper, we discuss about the disturbance rejection property and measurement noise effect of discrete-time DOB. Especially, we will focus on revealing the role of sampling time in designing the discrete-time DOB and show the validity of analysis through simulations and experiments for optical disk drive systems.