• 인터넷정보학회논문지
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• 제4권4호
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• pp.45-51
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• 2003

일반적으로 퍼지객체지향자료모형에서 속성값은 퍼지집합을 표현한다. 만일 퍼지객체지향자료모형에서 속성값을 구간값 퍼지집합으로 표현할 수 있다면, 퍼지객체지향자료모형에서 사용하는 속성값을 더 유연하게 표현하는 것이 가능하다. 퍼지객체지향자료모형의 상속구조에 나타나는 프레임내에 있는 속성값을 구하기 위해 구간값 퍼지집합을 사용하는 우선순위 논리곱연산을 이용하여 계산한다. 이 방법은 속성값의 소속정도가 기존의 퍼지집합이 아닌 구간값 퍼지집합으로 표현하는 지식정보처리분야에서 사용할 수 있다.

• 운동과학
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• 제26권3호
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• pp.223-228
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• 2017

PURPOSE: This study investigated the protective role of high-intensity interval training against acute liver injury induced by D-galactosamine (D-Gal)/lipopolysaccharide (LPS). METHODS: A total of 30 male BALB/c mice aged 5-week were randomly assigned to high-intensity, interval training group (EX, n=10) or control group in cage (Non-EX, n=20) for 10 weeks. Peritoneal injection of D-Gal (700 mg/kg body weight) and LPS ($10{\mu}g/kg$ body weight) was applied to induce acute liver injury, and liver tissue was harvested 6 hours after the injection. Hematoxylin and Eosin (H&E) staining was used for liver histology. Real-time PCR was used to quantify expression of pro-inflammatory and anti-inflammatory genes in the liver. RESULTS: The liver histology showed that D-Gal/LPS treatment resulted in hepatic damage and increased number of neutrophils in conjunction with upregulation of hepatic IL-6 and $TNF-{\alpha}$ mRNAs and downregulation of hepatic $PPAR{\alpha}$ and SIRT1 mRNAs. On the other hand, the 10-week interval training resulted in a significant improvement in cardiorespiratory fitness assessed as run time to exhaustion on a treadmill. In addition, the interval training attenuated the D-Gal/LPS-induced liver damage and increased number of neutrophil in conjunction with downregulation of hepatic IL-6 and $TNF-{\alpha}$ mRNAs and upregulation of hepatic $PPAR{\alpha}$ and SIRT1 mRNAs. CONCLUSIONS: This study suggests that high-intensity interval training suppresses the D-Gal and LPS-induced acute liver damage and inflammatory responses.

• 대한산업공학회지
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• 제41권5호
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• pp.439-446
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• 2015

Recently, the importance of one-class classification problem is more increasing. However, most of existing algorithms have the limitation on providing the information that effects on the prediction of the target value. Motivated by this remark, in this paper, we suggest an efficient one-class classifier using hyper-rectangles (H-RTGLs) that can be produced from intervals including observations. Specifically, we generate intervals for each feature and integrate them. For generating intervals, we consider two approaches : (i) interval merging and (ii) clustering. We evaluate the performance of the suggested methods by computing classification accuracy using area under the roc curve and compare them with other one-class classification algorithms using four datasets from UCI repository. Since H-RTGLs constructed for a given data set enable classification factors to be visible, we can discern which features effect on the classification result and extract patterns that a data set originally has.

• Journal of Communications and Networks
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• 제7권2호
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• pp.126-134
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• 2005

Reducing energy consumption in mobile hosts (MHs) is one of the most critical issues in wireles/mobile networks. IP paging protocol at network layer and power saving mechanism (PSM) at link layer are two core technologies to reduce the energy consumption of MHs. First, we investigate the energy efficiency of the current IEEE 802.11 power saving mechanism (PSM) when IP paging protocol is deployed over IEEE 802.11 networks. The result reveal that the current IEEE 802.11 PSM with a fixed wakeup interval (i.e., the static PSM) exhibits a degraded performance when it is integrated with IP paging protocol. Therefore, we propose an adaptive power saving mechanism in IEEE 802.11-based wireless IP networks. Unlike the static PSM, the adaptive PSM adjusts the wake-up interval adaptively depending on the session activity at IP layer. Specifically, the MH estimates the idle periods for incoming sessions based on the exponentially weighted moving average (EWMA) scheme and sets its wake-up interval dynamically by considering the estimated idle period and paging delay bound. For performance evaluation, we have conducted comprehensive simulations and compared the total cost and energy consumption, which are incurred in IP paging protocol in conjunction with various power saving mechanisms: The static PSM, the adaptive PSM, and the optimum PSM. Simulation results show that the adaptive PSM provides a closer performance to the optimum PSM than the static PSM.

• 한국도로학회논문집
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• 제19권5호
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• pp.1-11
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• 2017

PURPOSES : This study is aimed at development of a stochastic pavement deterioration forecasting model using National Highway Pavement Condition Index (NHPCI) to support infrastructure asset management. Using this model, the deterioration process regarding life expectancy, deterioration speed change, and reliability were estimated. METHODS : Eight years of Long-Term Pavement Performance (LTPP) data fused with traffic loads (Equivalent Single Axle Loads; ESAL) and structural capacity (Structural Number of Pavement; SNP) were used for the deterioration modeling. As an ideal stochastic model for asset management, Bayesian Markov multi-state exponential hazard model was introduced. RESULTS:The interval of NHPCI was empirically distributed from 8 to 2, and the estimation functions of individual condition indices (crack, rutting, and IRI) in conjunction with the NHPCI index were suggested. The derived deterioration curve shows that life expectancies for the preventive maintenance level was 8.34 years. The general life expectancy was 12.77 years and located in the statistical interval of 11.10-15.58 years at a 95.5% reliability level. CONCLUSIONS : This study originates and contributes to suggesting a simple way to develop a pavement deterioration model using the total condition index that considers road user satisfaction. A definition for level of service system and the corresponding life expectancies are useful for building long-term maintenance plan, especially in Life Cycle Cost Analysis (LCCA) work.

• 전기전자학회논문지
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• 제21권2호
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• pp.146-149
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• 2017

본 논문에서는 GM Tube 및 NaI(TI) 검출기를 사용한 Wide-Range 방사선 측정 시스템을 제안한다. 제안하는 시스템은 NaI(Tl) 검출기 및 GM Tube의 검출기 신호를 제어, 계수할 수 있게 최적화한 하나의 소형 모듈로 설계한 다. 방사선량은 2개의 검출기를 연동하여 Wide-range인 0.1uSv/h~10mSv/h 구간에서 측정되고, 측정구간이 중복되는 지점인 10uSv/h~100uSv/h에서는 2개의 검출기가 동시에 동작한다. 방사선량은 중첩된 방사선 측정 가능 구간에 대해 적정한 구간에서 해당 검출기 기능의 On/Off를 제어하는 Wide-Range 방사선 측정 알고리즘을 이용하여 선택 적용하였다. 제안된 시스템의 성능을 평가하기 위하여 공인시험기관에서 실험한 결과, 각 구간별로 측정 불확도가 ${\pm}7.5%$로 측정되어 국제 표준인 ${\pm}15%$ 이하에서 정상동작 됨이 확인되었다.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2001년도 춘계정기학술대회
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• pp.377-381
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• 2001

An ATMS(Assumption-based Truth Maintenance System) has been widely used for maintaining the truth of information by detecting and solving contradictions in nile-based systems. But the ATMS can not correctly maintain the truth of the information in case that the generated information is satisfied within a time interval or includes data about temporal relations of events in time varying situations, because it has no mechanism manipulating temporal data. In this paper, The extended ATMS method is proposed, which can maintain the truth of the information in the inference system using information changing over time or temporal relations of events. In order to maintain contexts generated by relations of events, the label representation method is modified, the disjunction, conjunction simplification method in the label-propagation procedure and nogood handling method of the conventional ATMS are modified, too.

• 한국수자원학회논문집
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• 제49권5호
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• pp.411-422
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• 2016

우리나라는 수공구조물 설계할 때 강우빈도해석과 강우-유출 모형으로 홍수량을 산정하여 사용하고 있다. 그러나 강우자료의 확률분포 및 자료기간 등에 따른 매개변수 추정에 많은 불확실성이 존재하나 이를 고려한 해석은 이루어지지 않고 있다. 이러한 점에서 Gumbel 분포형과 확률가중 모멘트법을 기준으로 확률강우량의 신뢰구간을 평가함과 동시에 매개변수의 불확실성을 평가하는데 있어서 우수한 성능을 발휘하는 Bayesian방법을 도입하여 서울지역의 확률강우량의 불확실성을 정량적으로 평가하였다. 두 가지 방법의 비교결과 확률가중모멘트법의 신뢰구간이 Bayesian 방법의 불확실성 구간보다 전반적으로 크게 나타났다. 신뢰구간의 경우 정규분포를 따르기 때문에 좌우대칭의 형태를 갖는 반면에 Bayesian 방법의 불확실성은 Gumbel 분포로부터 유도되어, 보다 현실적인 불확실성 평가가 가능하였다. 자료의 구간 및 기간에 따른 확률강우량의 불확실성을 평가한 결과 자료에 증가에 따른 불확실성 감소를 확인할 수 있었으며, Bayesian 방법이 자료 증가에 따른 불확실성 범위 감소가 보다 뚜렷하게 나타나는 것을 확인할 수 있었다.

• 대한전자공학회논문지SP
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• 제45권3호
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• pp.80-92
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• 2008

기존의 영상 부호화 표준들보다 높은 압축 성능을 얻기 위해 부호화 효율 측면에서 우수한 기술들이 가장 최근에 완성된 영상 부호화 표준인 H.264/AVC에 채택되었다. 가변 블록 단위의 움직임 예측/보상과 다양한 방향성을 통한 화면 내 예측 방법 등의 영상 부호화 기술들의 발달에도 불구하고, 이산 여현 변환은 초기 영상 부호화 표준에서부터 계속적으로 사용되고 있다. 일반적으로 실제 영상 신호가 부호화될 때 생성되는 잔여 신호의 상관 계수 값은 0.5 미만이다. 하지만, 이러한 상관 계수 값의 범위는 이산 여현 변환이 최적의 성능을 나타내는 범위가 아니며, 상관 계수의 범위가 -0.5에서 0.5일 경우 차선의 변환인 이산 정현 변환이 이산 여현 변환과 함께 영상 호화에 사용될 수가 있다. 본 논문에서는 이산 정현 변환과 H.264/AVC에서의 정수 여현 변환 중 최적의 변환을 율-왜곡 최적화 과정을 이용하여 선택적으로 사용하는 선택 변환을 제안한다. 제안하는 방법을 통해 H.264/AVC의 JM 10.2와 비교하여 상대적으로 높은 비트율에서 최대 0.71 dB의 BD-PSNR 향상을 얻을 수가 있었다.

• Structural Engineering and Mechanics
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• 제37권4호
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• pp.427-442
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• 2011

In fatigue life design of mechanical components, uncertainties arising from materials and manufacturing processes should be taken into account for ensuring reliability. A common practice is to apply a safety factor in conjunction with a physics model for evaluating the lifecycle, which most likely relies on the designer's experience. Due to conservative design, predictions are often in disagreement with field observations, which makes it difficult to schedule maintenance. In this paper, the Bayesian technique, which incorporates the field failure data into prior knowledge, is used to obtain a more dependable prediction of fatigue life. The effects of prior knowledge, noise in data, and bias in measurements on the distribution of fatigue life are discussed in detail. By assuming a distribution type of fatigue life, its parameters are identified first, followed by estimating the distribution of fatigue life, which represents the degree of belief of the fatigue life conditional to the observed data. As more data are provided, the values will be updated to reduce the credible interval. The results can be used in various needs such as a risk analysis, reliability based design optimization, maintenance scheduling, or validation of reliability analysis codes. In order to obtain the posterior distribution, the Markov Chain Monte Carlo technique is employed, which is a modern statistical computational method which effectively draws the samples of the given distribution. Field data of turbine components are exploited to illustrate our approach, which counts as a regular inspection of the number of failed blades in a turbine disk.