• 한국소음진동공학회논문집
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• 제18권5호
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• pp.503-508
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• 2008

In this paper, various methods to improve the planetary gear noise in vehicles were introduced. Those cases of improvement have been used as good guidelines and references to prevent planetary noise problems. In this research, different types of planetary gear systems were also analyzed. The consequences of those analysis said in common that the planetary gear set generating noise mainly is the one which takes power directly from the turbine. Furthermore, a frequency versus vibration level map was introduced to judge how to solve the noise problem quickly in a vehicle development process. Besides, it is provided a predicting method which planetary gear set most contributes to noise problem taking in the vehicle and how to design the planetary gear set robustly.

• Bulletin of the Korean Chemical Society
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• 제30권4호
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• pp.794-796
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• 2009

We have studied the structures and stabilities of Au6 to explore the origin of the large discrepancy between relative energies obtained from the density functional theory (DFT) and ab initio correlated levels of theory. The MP2 methods significantly overestimate the stability of the non-planar isomer when the double-$\zeta$ polarization quality of basis sets, such as LANL2DZ+1f and CEP31G+1f, are used. However, we show that such preference for the non-planar structure at the MP2 level mainly originates from the large basis set superposition error.

• 전기학회논문지
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• 제67권3호
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• pp.419-426
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• 2018

An useful and effective design method for the gas identification system is presented in this paper. The proposed gas identification system adopts hierarchical structure with two level rule base combining fuzzy sets with rough sets. At first, a hybrid genetic algorithm is used in grouping the array sensors of which the measured patterns are similar in order to reduce the dimensionality of patterns to be analyzed and to make rule construction easy and simple. Next, for low level identification, fuzzy inference systems for each divided group are designed by using TSK fuzzy rule, which allow handling the drift and the uncertainty of sensor data effectively. Finally, rough set theory is applied to derive the identification rules at high level which reflect the identification characteristics of each divided group. Thus, the proposed method is able to accomplish effectively dimensionality reduction as well as accurate gas identification. In simulation, we demonstrated the effectiveness of the proposed methods by identifying five types of gases.

• 한국철도학회논문집
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• 제12권3호
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• pp.342-347
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• 2009

고장모드, 영향 및 임계분석(FMECA)은 시스템의 구성요소가 갖는 잠재적인 고장모드와 각 고장모드가 시스템에 미치는 영향을 평가하는 도구로 활용된다. 일반적으로 FMECA는 관련 전문가들의 의견에 따라 고장모드의 심각도와 치명도를 평가하여 이를 위험도 매트릭스의 양축으로 나타냄으로써 중요한 고장모드에 대한 분석을 수행한다. 그러나 이러한 절차는 평가가 전문가의 주관에 의해 이루어져 결과에 불확실성이 포함될 수밖에 없다. 따라서 본 논문에서는 최소절단집(MCS)와 퍼지이론을 이용한 새로운 FMECA 절차를 제안한다. 심각도 평가에 있어서는 MCS를 이용함으로써 객관적인 구조적 중요도를 평가할 수 있게 하였고, 치병도의 평가에서는 설비의 대표적인 고장률을 이용하였다. 그리고 두 지수를 종합하기 위해 퍼지 전문가 시스템을 구성하여 종합적인 위험도를 평가하였다.

• 융합신호처리학회논문지
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• 제1권1호
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• pp.23-31
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• 2000

본 논문에서는 물체의 경계나 형태 추출을 위하여 레벨 세트 이론을 바탕으로 한 새로운 곡선 전개방법을 제안한다. 특히 전처리 과정에서 잡음의 효과적 처리를 위하여 기존의 필터 방식들이 가지는 단점인 경계 부분의 bluning 현상을 줄이고 정확한 에지 위치를 보존할 수 있는 비등방성 확산 필터(anisotropic diffusion filter)를 사용한다. 기존의 레벨 세트 방식이 수축이나 팽창 중 단지 한가지의 방식만 적용되어지는 반면, 제안한 방법은 물체의 경계 추출시 팽창과 수축이 통시에 가능하므로 특히 초기 곡선이 여러 물체에 걸쳐져 있는 경우에도 정확한 형태 추출이 가능하였다. 아울러 초기 곡선의 설정이 위치나 형태에 거의 제한을 받지 않기 때문에 추출을 원하는 영역이 아주 조금만 포함되어 있어도 정화한 형태 추출이 가능하였다.

• 대한전자공학회논문지SD
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• 제47권5호
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• pp.80-86
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• 2010

전형적인 버스 시스템 구조는 공용버스 내에 여러 개의 마스터와 슬레이브, 아비터 그리고 디코더 등으로 구성되어 있다. 복수의 마스터가 동시간대에 버스를 이용할 수 없으므로, 아비터는 이를 중재하는 역할을 수행한다. 아비터가 어떠한 중재방식 을 선택하는가에 따라 버스 사용의 효율성이 결정된다. 기존의 중재 방식에는 Fixed Priority 방식, Round-Robin 방식, TDMA 방식, Lottery 방식 등이 연구되고 있는데, 버스 우선권이 주로 고려되어 있다. 본 논문에서는 마스터별 버스 점유율을 연산하는 블록을 이용하는 버스중재 방식을 제안하고, TLM(Transaction Level Model)을 통해 다른 중재 방식과 비교하여 성능을 검증하였다. 성능분석 결과, 기존의 Fixed Priority 방식과 Round-Robin 방식은 버스점유율을 설정할 수 없었으며 기존의 TDMA, Lottery 중재방식의 경우에는 100,000 사이클 이상에서 사용자가 설정한 버스점유율과 비교하여 각각 최대 50%, 70%의 오차가 발생하였다. 반면에 점유율 고려 중재방식의 경우에는 약 1000 사이클 이후부터 사용자가 설정한 버스점유율과 비교하여 1% 이하의 오차를 유지하였다.

• 종양간호연구
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• 제7권1호
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• pp.26-35
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• 2007

Purpose: The purpose of this study was to set the strategy that clinical nurses can efficiently cope with the stress from bereavement care, by examining and analyzing stress factors and coping methods of nurses' bereavement care. Methods: A total of 628 nurses were recruited from four university hospitals, two cancer specialized hospitals, and three public hospitals. Stress was measured using the bereavement care stress measurement tool, and coping was done using the cope with stress scale. Results: The stress level about bereavement care of the nurses working in the cancer unit was significantly higher than the level of the nurses working in the general unit. However, there was no difference of coping level between nurses working in cancer unit and general unit. Conclusions: It is important to ensure the methods that contrive to perform bereavement care efficiently by generating hospice nurses and by activating the system for nurses specialist who perform bereavement care.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제15권8호
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• pp.2764-2782
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• 2021

Existing city-level boundary nodes identification methods need to locate all IP addresses on the path to differentiate which IP is the boundary node. However, these methods are susceptible to time-delay, the accuracy of location information and other factors, and the resource consumption of locating all IPes is tremendous. To improve the recognition rate and reduce the locating cost, this paper proposes an algorithm for city-level boundary node identification based on bidirectional approaching. Different from the existing methods based on time-delay information and location results, the proposed algorithm uses topological analysis to construct a set of candidate boundary nodes and then identifies the boundary nodes. The proposed algorithm can identify the boundary of the target city network without high-precision location information and dramatically reduces resource consumption compared with the traditional algorithm. Meanwhile, it can label some errors in the existing IP address database. Based on 45,182,326 measurement results from Zhengzhou, Chengdu and Hangzhou in China and New York, Los Angeles and Dallas in the United States, the experimental results show that: The algorithm can accurately identify the city boundary nodes using only 20.33% location resources, and more than 80.29% of the boundary nodes can be mined with a precision of more than 70.73%.

• 한국전문물리치료학회지
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• 제23권1호
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• pp.55-64
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• 2016

Background: The International Classification of Functioning, Disability, and Health-core set (ICF-core set) for children and youth (CY) with cerebral palsy (CP) provides a useful conceptual framework and a guide for health care planning and measuring the changes brought by interventions across a multitude of dimensions from body functions to personal activities, social participation, and environmental factors for them. Objects: This single case study was reported to illustrate the use of a goal directed approach in applying the ICF-core set for CY with CP from a physical therapist perspective. Methods: An eleven year old boy with spastic CP, Gross Motor Function Classification System (GMFCS) level V, and his mother participated in an evaluation of his functioning state. The intervention goal was set through an interview using the ICF-core set, Canadian Occupational Performance Measure (COPM) and Goal Attainment Scale (GAS). Physical therapy was carried out on an outpatient basis using a goal directed approach for 30 min, 1 time/week during 12 weeks and the boy's gross motor function was assessed using the Gross Motor Function Measure (GMFM)-66 version (item set 2) before and after the intervention. Results: As measured by the boy's mother, the COPM score showed a meaningful clinical change (performance=mean 3.5, satisfaction=mean 2.5) and the T-score of GAS changed 34.4 after the goal directed approach. The GMFM-66 (item set 2) score changed from 31.8 to 38.7 and evaluation using the ICF-core set displayed improvement in 6 items of activity level between before and after the intervention. Conclusion: The ICF-core set for CY with CP is useful for understanding the overall functioning of CY with this condition and provides an opportunity to share and integrate information and opinions from different disciplines. We consider it as a useful tool in the universal language for the therapy and education of CY with CP.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1995년도 춘계학술대회
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• pp.155-159
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• 1995

A design method that can easily construct intelligent patient monitoring systems is proposed. To achieve the design method, the SES/MB concept and a discrete event-based logic control formalism based on a set theory is introduced. In this control paradigm the controller expects to receive confirming sensor responses to its control commands within definite time windows determined by DEVS model of the system under control. Because data to be used for rule-based symbolic reasoning are to be abstracted, several AI methods are applied the processes. These methods are applied to intelligent patient monitoring systems so that they facilitate transformation from low level raw data to high level linguistic data. Model-based system representations have advantages of reusability, extensibility, flexsibility, independent testability and encapsulation.