• 정보과학회 논문지
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• 제43권1호
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• pp.80-86
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• 2016

화행이란 발화 속에 포함되어 있는 화자에 의해 의도된 언어적 행위이다. 대화 시스템에서 입력된 발화에 적합한 화행을 분류하는 것은 중요하다. 기존의 화행분류에 관한 연구는 규칙기반과 기계학습 기반의 방법을 많이 사용한다. 본 논문에서는 대표적인 기계학습 방법인 지지벡터기계(SVM)와 변환기반 학습(TBL)을 조합한 화행 분류 방법을 제안한다. 이를 위해, 화행별 학습 발화의 수에 기반하여 분류 우선순위를 조정함으로써 지지벡터기계의 분류 편향 문제를 해결하였고, 오답일 확률이 높은 분류 결과에 대해서 변환 기반 학습을 통해 생성된 보정 규칙을 적용함으로써 화행분류 성능을 개선하는 방법을 제안한다. 본 논문에서 화행별 학습 발화 수의 차이를 고려한 분류 우선순위 변화와 후보정 규칙을 이용한 화행분류 방법을 실험을 통해 평가하였으며, 이는 학습 발화 수가 낮은 화행의 우선순위를 고려하지 않은 기존의 화행 분류보다 성능이 향상되었다.

• 한국지리정보학회지
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• 제18권1호
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• pp.156-169
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• 2015

본 연구는 SWAT(Soil and Water Assessment Tool) 모형을 이용하여 임하댐 유역($1,355.5km^2$)을 대상으로 RCP(AR5) 기후변화 시나리오에 따른 미래 수문순환 영향을 평가하였다. 3지점의 실측된 유출량을 활용하여 모형의 보정(2002~2007년) 및 검증(2008~2013년)을 실시하였다. 검 보정 결과 결정계수($R^2$)는 0.70~0.85로, Nash-Sutcliffe 모형 효율(NSE)은 0.67~0.82로 분석되어 신뢰성 있는 유출량 모의 결과를 나타내었다. 기후변화 시나리오는 기상청에서 제공하는 HadGEM3-RA 모형의 RCP 4.5 및 8.5 시나리오를 수집하여, 과거 34년(1980-2013, baseline period)의 기상자료를 기준으로 편이보정(Bias Correction)하여 SWAT모형에 적용하였다. 기후변화 분석 결과 강수량과 평균기온이 10.8%, $4.9^{\circ}C$ 증가하였으며, 강수량과 기온의 증가로 증발산 11.2%, 토양수분 1.9%, 지표유출 10.0%, 중간유출 12.1%, 회귀유출 18.2%이 각각 증가함에 따라 총 하천유출량이 11.2% 증가하였다.

• Structural Engineering and Mechanics
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• 제18권3호
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• pp.343-362
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• 2004

Rocking response of rigid bodies with rectangular footprint, freely standing on horizontal rigid plane is studied analytically. Bodies are subjected to simulated single component of horizontal earthquakes. The effect of baseline correction, applied to simulated excitations, on the rocking response is first examined. The sensitiveness of rocking motion to the details of earthquakes and geometric properties of rigid bodies is investigated. Due to the demonstrated sensitivity of rocking response to these factors, prediction of rocking stability must be made in the framework of probability theory. Therefore, using a large number of simulated earthquakes, the effects of duration and shape of intensity function of simulated earthquakes on overturning probability of rigid bodies are studied. In the case when a rigid body is placed on any floor of a building, the corresponding probability is compared to that of a body placed on the ground. For this purpose, several shear frames are employed. Finally, the viability of the energy balance equation, which was introduced by Housner in 1963 and widely used by nuclear power industry to estimate the rocking stability of bodies, is evaluated. It is found that the equation is robust. Examples are also given to show how this equation can be used.

• 한국근적외분광분석학회:학술대회논문집
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• 한국근적외분광분석학회 2001년도 NIR-2001
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• pp.1284-1284
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• 2001

The transesterification of molten ethylene/vinylacetate (EVA) copolymers by octanol as a reagent and sodium methoxide as a catalyst in an extruder has been monitored by on-line near infrared (NIR) spectroscopy. A total of 60 NIR spectra were acquired for 37 minutes with the last spectrum recorded 31 minutes after the addition of octanol and catalyst was stopped. The experimental spectra show strong baseline fluctuations which are corrected for by multiplicative scatter correction (MSC). The chemometric methods of orthogonal projection approach (OPA) and multivariate curve resolution (MCR) were used to resolve the spectra and to derive concentration profiles of the species. The detailed analysis reveals the absence of completely pure variables that leads to small errors in the calculation of pure spectra. The initial estimation of a concentration that is necessary as an input parameter for MCR also presents a non-trivial task. We obtained results that were not ideal but applicable for practical concentration control. They enable a fast monitoring of the process in real-time and resolve the spectra of the EVA copolymer and the ethylene/vinyl alcohol (EVAL) copolymer to be very close to the reference spectra. The chemometric methods used and the decomposed spectra are discussed in detail.

• Smart Structures and Systems
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• 제25권5호
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• pp.531-541
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• 2020

This paper demonstrates the possibility of evaluating the safety of a building right after an earthquake using consumer-grade surveillance cameras installed in the building. Two cameras are used in each story to extract the time history of interstory drift during the earthquake based on camera calibration, stereo triangulation, and image template matching techniques. The interstory drift of several markers on the rigid floor are used to estimate the motion of the geometric center using the least square approach, then the horizontal interstory drift of any location on the floor can be estimated. A shaking table collapse test of a steel building was conducted to verify the proposed approach. The results indicate that the accuracy of the interstory drift measured by the cameras is high enough to estimate the damage state of the building based on the fragility curve of the interstory drift ratio. On the other hand, the interstory drift measured by an accelerometer tends to underestimate the damage state when residual interstory drift occurs because the low frequency content of the displacement signal is eliminated when high-pass filtering is employed for baseline correction.

• 통상정보연구
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• 제12권4호
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• pp.171-192
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• 2010

In general, a stock index and its individual stocks are assumed to follow a random walk. A stock index is an important source of information and one that is seen by people everyday, regardless of their investment intentions. This paper examines the correlation between the KOSPI-the index that best reflects the Korean stock market and the macro - economic variables that have been found to influence the index by previous studies. The sample period considers the years after 2000 when the Korean stock market matured as restrictions on foreign investors were removed. For this purpose, a Vector Error Correction Model (VECM) and KOSPI equation with a general pacific approach were used. This paper aims at verifying the factors that determined the KOSPI after 2000 and at examining whether there was structural change in the investment environment. It also investigates changes in the factors determining the KOSPI's performance as a result of structural changes in the investment environment. The V AR (Vector Autoregressive) model including the nine variables was selected as a baseline model whose stability was tested using the unit root test. The results from the VECM and the structural changes in the investment environment can be summarized by the following Inner story points.

• Journal of Astronomy and Space Sciences
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• 제26권1호
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• pp.59-74
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• 2009

Relative navigation system is presented using GPS measurements from a single-channel global positioning system (GPS) simulator. The objective of this study is to provide the real-time inter-satellite relative positions as well as absolute positions for two formation flying satellites in low earth orbit. To improve the navigation performance, the absolute states are estimated using ion-free GRAPHIC (group and phase ionospheric correction) pseudo-ranges and the relative states are determined using double differential carrier-phase data and singled-differential C/A code data based on the extended Kalman filter and the unscented Kalman filter. Furthermore, pseudo-relative dynamic model and modified relative measurement model are developed. This modified EKF method prevents non-linearity of the measurement model from degrading precision by applying linearization about absolute navigation solutions not about the priori estimates. The LAMBDA method also has been used to improve the relative navigation performance by fixing ambiguities to integers for precise relative navigation. The software-based simulation has been performed and the steady state accuracies of 1 m and 6 mm ($1{\sigma}$ of 3-dimensional difference errors) are achieved for the absolute and relative navigation using EKF for a short baseline leader/follower formation. In addition, the navigation performances are compared for the EKF and the UKF for 10 hours simulation, and relative position errors are mm-level for the two filters showing the similar trends.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.353-356
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• 2010

평행 초음속-아음속 후류유동에서 혼합증대에 관한 수치적인 연구를 실험결과와의 비교를 통하여 수행하였다. 이번 연구의 첫 번째 목적은 실험에서 사용된 조건으로 정확하게 수치적으로 모사하는데 있다. Pitot 압력을 이용하여 수치계산결과와 실험치와 비교하였을 때 서로 일치된 결과를 얻었으며, 그 중에서 압축성 수정을 가미한 $k-{\omega}$ SST 난류모델의 계산결과가 가장 좋은 것으로 나타났다. 게다가 기존의 유동조건에서 공동의 위치, 배열수에 변화를 주면서 혼합특성을 비교/연구하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2015년도 학술발표회
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• pp.145-145
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• 2015

본 연구에서는 SWAT(Soil and Water Assessment Tool) 모형을 이용하여 고랭지 농업 지역인 해안분지유역($63km^2$)을 대상으로 RCP 기후변화 시나리오에 따른 미래 수문순환 전망을 평가하였다. 모형의 보정(2009년-2010년) 및 검증(2011년)은 3지점의 실측된 유출량을 활용하여 실시하였다. 모형의 보정 및 검증 결과 결정계수($R^2$)는 X.XX-X.XX이고, Nash-Sutcliffe 모형 효율(NSE)는 X.XX-X.XX으로 분석되어 신뢰성 있는 유출량 모의 결과를 나타내었다. 미래 기후변화 시나리오는 기상청에서 제공하는 HadGEM3-RA 모형의 RCP 4.5 및 8.5 자료를 수집하였다. 다음으로 과거 13년(1999년-2011년, Baseline period)의 기상자료를 기준으로 편이보정(Bias Correction)기법을 이용하여 오차보정 후, SWAT 모형에 적용하여 2040s(2020년-2059년) 및 2080s(2060년-2099년) 기간에 대해서 분석하였다. 그 후, 수문요소인 증발산, 토양수분, 지표유출, 중간유출, 회귀유출 및 하천유출량의 변화량을 분석하여 고랭지 농업 유역의 기후변화에 따른 미래 수문순환을 전망하였다.

• 한국지진공학회논문집
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• 제25권6호
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• pp.283-292
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• 2021

In this study, a structural health monitoring system for cable-stayed bridges is developed. In the system, condition assessment of the structure is performed based on measured records from seismic accelerometers. Response indices are defined to monitor structural safety and serviceability and derived from the measured acceleration data. The derivation process of the indices is structured to follow the transformation from the raw data to the outcome. The process includes noise filtering, baseline correction, numerical integration, and calculation of relative differences. The system is packed as a condition assessment program, which consists of four major processes of the structural health evaluation: (i) format conversion of the raw data, (ii) noise filtering, (iii) generation of response indices, and (iv) condition evaluation. An example set of limit states is presented to evaluate the structural condition of the test-bed and cable-stayed bridge.