• 한국정밀공학회지
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• 제6권1호
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• pp.33-44
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• 1989

A controller disign method is proposed for multivariable nonlinear stochastic systems with hard nonlinearities such as Coulomb friction, backlash and saturation. In order to take the nonlinearities into account statistical linearization techniques are used. And multi- variable pole placement techniques are applied to design controller for the statistically linearized multivariable systems. The basic concept of the controller design method is to solve two coupled equations, characteristic equation and Lyapunov equation, simultaneously and iteratively for statistically linearized multivariable stochastic systems. An aircraft with saturation serves as a design example. The design example illustrates the influence of nonlinear effects. The results of the analysis are compared to Monte Carlo simulation to test their accuracy.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.102-109
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• 1997

A study to determine a proper sensor placement was developed to improve force identification. Improper selection of response position cause erroneous result in force identification problem. This paper presents two methods to improve the conditioning of the system's FRM(Frequency Response Matrix) which affects the accuracy of result. The basic strategy of the two methods in selecting the response position is to let the smallest singular value be as large as possible by maximizing the orthogonality of FRM. The suggested methods are tested numerically with a fixed-fixed beam model. The test results show that the proposed methods are very effective in dealing with the force identification problem.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권2호
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• pp.103-110
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• 2004

This paper proposes a new method on the EMG AR(autoregressive) modeling in pattern recognition for various head motions. The proper electrode placement in applying AR or cepstral coefficients for EMG signature discrimination is investigated. EMG signals are measured for different 10 motions with two electrode arrangements simultaneously. Electrode pairs are located separately on dominant muscles(S-type arrangement), because the bandwidth of signals obtained from S-type placement is wider than that from C-type(closely in the region between muscles). From the result of EMG pattern recognition test, the proposed mIAR(modified integrated mean autoregressive model) technique improves the recognitions rate around 17-21％ compared with other the AR and cepstral methods.

• Journal of Power Electronics
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• 제12권5호
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• pp.830-841
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• 2012

Active power filters (APF) can be employed for harmonic compensation in power systems. In this paper, a fuzzy based method is proposed for identification of probable APF nodes of a radial distribution system. The modified adaptive particle swarm optimization (MAPSO) technique is used for final selection of the APFs size. A combination of Fuzzy-MAPSO method is implemented to determine the optimal allocation and size of APFs. New fuzzy membership functions are formulated where the harmonic current membership is an exponential function of the nodal injecting harmonic current. Harmonic voltage membership has been formulated as a function of the node harmonic voltage. The product operator shows better performance than the AND operator because all harmonics are considered in computing membership function. For evaluating the proposed method, it has been applied to the 5-bus and 18-bus test systems, respectively, which the results appear satisfactorily. The proposed membership functions are new at the APF placement problem so that weighting factors can be changed proportional to objective function.

• 산업공학
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• 제13권2호
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• pp.195-203
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• 2000

This paper considers the problem of sequencing printed circuit boards(PCBs) on an automatic surface mount device(SMD) placement machine in order to minimize total setup time. Since the total set of component feeders needed by all boards cannot be loaded simultaneously on the magazine, the setup must be made between two successive boards in the sequence. It is assumed that the setup time depends on the number of component feeders to be replaced in the magazine. An important characteristic is that each feeder occupies a different number of slots in the magazine. This problem is equivalent to travelling salesman problem(TSP) except that the distances between two cities, that is, the setup times between two boards, are not known in advance. So, TSP-based heuristics with new distance functions are presented and their performances are compared through various test problems. Computational results indicate that our heuristics outperform existing methods.

• 전기학회논문지
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• 제61권1호
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• pp.148-154
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• 2012

For a successful checkpointing strategy, we should place checkpoints so as to optimize fault-tolerance capability of real-time systems. This paper presents a novel scheme of checkpoint placement for real-time systems with periodic multi-tasks. Under the influence of transient faults, multi-tasks are scheduled by the Rate Monotonic (RM) algorithm. The optimal checkpoint intervals are derived to maximize the probability of task completion. In particular, this paper is concerned about the general case that the deadline of a task is longer than the period. Compared with the special condition that the deadline is equal to or less than the period, this general case causes a more complicate test procedure for schedulability of the RM algorithm with respect to a given set of checkpoint re-execution vectors. The probability of task completion is also derived in a more complex form. A case study is given to show the applicability of the proposed scheme.

• 대한치과보철학회지
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• 제51권4호
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• pp.269-275
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• 2013

연구 목적: 이 연구는 임플란트 직경, 길이 및 식립 부위가 임플란트의 안정성에 미치는 영향을 후향적 평가를 통해 비교, 분석하고자 하였다. 연구 대상 및 방법: 72명의 환자에게 식립된 총 90개의 임플란트(US II plus$^{TM}$, Osstem co, Busan, Korea)를 대상으로 임플란트 식립 직후와 인상 채득 당시에 공진주파수분석법(RFA)으로 임플란트 안정성 지수(ISQ)가 측정되었다. 상 하악에 식립된 직경은 4 mm와 5 mm이고 길이는 10 mm, 11.5 mm, 13 mm인 임플란트가 실험대상으로 선택되었다. 측정된 ISQ 값의 평균과 표준편차를 구하고 우선적으로 성별에 따른 차이를 확인하기 위하여 Independent t-test를 시행하였다. 임플란트 직경, 길이, 식립부위에 따른 ISQ 값의 실험군간 차이는 One-way ANOVA를 이용해 분석하였고, 사후검정을 위해 Tukey HSD test가 사용되었다. 임플란트 식립시와 인상채득시의 차이는 paired t-test로 분석하였다. 결과:인상채득시가 임플란트 식립 직후보다 임플란트 안정성의 증가가 관찰되었다. 임플란트 길이가 증가할수록 ISQ 값은 증가하였으나 통계적으로 유의적인 차이를 보이지 않았다. 직경 5 mm 임플란트는 4 mm 임플란트 보다 유의성 있게 높은 ISQ 값을 보였다(P<.05). 하악에 식립된 임플란트가 상악보다 더 높은 ISQ값을 보였다(P<.05). 결론:본연구결과, 임플란트 안정성을 높이기 위해서는 직경이 큰 임플란트를 사용하는 것이 효과적임을 알 수 있었다. 또한, 상악보다는 하악에서 더 높은 임플란트 안정성이 확인되었다. 임플란트 식립 직후의 일차 안정성보다 골유착 후 이차 안정성이 더 높게 나타남으로서 RFA를 이용한 방법이 골유착을 통한 임플란트 안정성의 변화를 평가함에 있어 임상적으로 유용한 것으로 판단된다. 임플란트 안정성 평가와 이에 영향을 주는 요소들에 대한 고려는 임플란트 하중 시기를 결정하고 임플란트 성공률을 증가시키는데 도움이 될 것이다.

• Journal of the Korean Data and Information Science Society
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• 제24권6호
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• pp.1349-1357
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• 2013

임상시험에서 적당한 크기의 표본 수 결정은 통계적으로 유의한 연구결과의 도출과 연구수행의 효율적인 비용을 산출하기 위해서 중요한 사항 중의 하나이다. 기존의 비열등성 시험에서 표본 수 계산방법에는 t 검정법을 이용한 모수적 방법이 있고, Wilcoxon 순위합 검정을 이용하여 Wang 등 (2003)이 제안한 표본 수 계산방법을 Kim과 Kim (2007)이 비열등성 시험에 확장시켜 적용하여 제시한 비모수적 방법이 있다. 본 논문에서는 Orban과 Wolfe (1982)가 제안한 선형위치통계량의 검정법에 Kim (1994)이 계산한 검정력의 결과를 이용한 표본 수 계산 방법을 제안하고, 그에 따른 표본 수 계산결과를 기존에 제시된 표본 수 계산 결과와 비교하였다. 그 결과 기존의 방법들보다 본 논문에서 제안하는 방법으로 계산한 경우의 표본 수가 가장 작게 나왔다. 따라서 모집단에 대해서 구체적인 분포함수를 가정하기 힘든 경우 모수적 방법을 이용하게 되면 검정력이 떨어지거나 유의수준을 제어하지 못하는 문제점을 보완하고, 모수적 방법에 비해 표본 수가 크게 나와 시간이나 비용 면에서 효율적이지 않았던 Wilcoxon 순위합 검정을 이용한 방법의 단점을 보완할 수 있는 방법으로 본 논문에서 제시한 위치 (placement)를 이용한 표본 수 계산이 이용될 수 있다.

• The Journal of Korean Physical Therapy
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• 제13권3호
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• pp.529-535
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• 2001

The purpose of this study was to test that the exercise adaptive training enhance behavioral outcome significantly after focal brain ischemia in rats. After occlusion of middle cerebral artery in rats, they were housed in individual standard cages fur 24 hours. The control group was sacrificed 24 hours after ischemic event. The experimental group I was housed in standard cages for 7days. The experimental group ll was housed in enriched environment and had got exercise adaptive training fur 7days. The rats were examined five motor behavioral tests. In motor behavioral tests :postural reflex test, limb placement test, beam-walking test, rotarod test, horizontal wire test. The outcomes of control group and group I were significantly lower than the group II. The conclusion was that exercise adaptive training induced functional repair.

• 성인간호학회지
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• 제12권2호
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• pp.196-208
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• 2000

The purpose of the study was to explore the effect of 2 hour infusion of vancomycin(1g) in 200ml of isotonic saline every 12 hour on the frequency of "red man syndrome", phlebitis and length of peripheral catheter placement of infected patients, in order to provide safe infusion method for reducing vancomycinin-duced RMS and phlebitis. The subjects of the study consisted of 16 hospitalized patients; 3 oncology and gastro-intestinal patients, 1 neurological patient, 6 thoracic surgical patients and 6 orthopedic patients, who had received vancomycin from July to October in 1999 at S-hospital. The dependent variables were the incidence of RMS, phlebitis and the length of peripheral catheter placement. The incidence of RMS was checked by an inspector at the first night whenever the infusion method of vancomycin was changed. RMS was observed every 15 minutes during an hour for symptoms of RMS such as itching, erythema, chest pain and systolic blood pressure. Incidence of phlebitis was assessed by inspector twice a day from the insertion of peripheral catheter to the removal of the catheter. The data were analyzed by percentage, mean, $X^2$-test, t-test, repeated ANOVA, and logistic regression analysis using the SPSSWIN program. The results are summarized as follows; 1. No significant difference was identified in frequency of RMS between the experimental group and control group. 2. There was no significant difference in the change of systolic blood pressure as the time goes on between the experimental group and control group. 3. The incidence of phlebitis was significantly lower in the experimental group than in the control group. 4. The length of peripheral catheter placement was significantly longer in the experimental group than in the control group. 5. Other drugs administrated with vancomycin didn't influence the occurrence of phlebitis. However, the infusion method of vancomycin influenced the occurrence of phlebitis. The results suggest that 2 hour infusion of vancomycin(1g) in 200ml of isotonic saline every 12 hours may decrease the incidence of phlebitis and increase the length of peripheral catheter placement compared to 1 hour infusion of vancomycin(1g) in 100ml of isotonic saline every 12 hours. However, it does not reduce the incidence of RMS.