• 한국군사과학기술학회지
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• 제15권1호
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• pp.86-92
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• 2012

When missile is launched, a launcher needs to be leveled with accuracy to avoid the systems's instability. In general, a launcher is leveled by adjusting the stroke of leveling jacks; however, it is still challenge to control the leveling jacks fast and accurately. This paper thus proposed an innovative algorithm for compensating ground inclination of a missile launcher to expand operational field of a missile launcher. Using two inclinometers attached on a launcher, a base jack for leveling is selected and the mixed gradient where launcher stands on can be estimated. Due to the limited stroke, the launcher can compensate its ground inclination within maximum stroke margin. Then, the ground inclination of a launcher can be compensated by calculated angle using weighting factors. The effectiveness of proposed algorithm is proved with a prototype missile launcher.

• 인터넷정보학회논문지
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• 제21권6호
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• pp.81-94
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• 2020

This study developed evaluation indicators for the comfort experience of virtual reality (VR) headsets by classifying, defining, and weighting cybersickness-causing factors using the Delphi research method and analytic hierarchical process (AHP) approach. Four surveys were conducted with 20 experts on VR motion sickness. The expert surveys involved the 1) classification and definition of cybersickness-causing dimensions, classification of sub-factors for each dimension, and selection of evaluation indicators, 2) self-reassessment of the results of each step, 3) validity revaluation, and 4) final weighting calculation. Based on the surveys, the evaluation indicators for the comfort experience of VR headsets were classified into eight sub-factors: field of view (FoV)-device FoV, latency-device latency, framerate-device framerate, V-sync-device V-sync, rig-camera angle view, rig-no-parallax point, resolution-device resolution, and resolution-pixels per inch (PPI). A total of six dimensions and eight sub-factors were identified; sub-factor-based evaluation indicators were also developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.374-377
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• 1991

In this paper, it is proposed to improve the robustness of the Fast Recursive Least Squares(FRLS) algolithms with the exponential weighting, which is an important class of algolithms for adaptive filtering. It is well known that the FRLS algolithm is numerically unstable with exponential weighting factor ${\lambda}<1$. However, introducing some gains into this algolithms, numerical errors can be reduced. An accurately choice of the gains then leads to a numerically stable FRLS algolithm with a complexity of 8m multiplications and we shown it by computer simulations.

• 한국멀티미디어학회논문지
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• 제17권11호
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• pp.1286-1295
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• 2014

This paper suggests the way that it could improve the reliability about preference of user's feedback by adding weighting factor on sentiment analysis, and efficiently make a sentiment analysis of users' emotional perspective on the big data massively generated on twitter. To solve errors on earlier studies, this paper has improved recall and precision of sensibility determination by using sensibility dictionary subdivided sentiment polarity based on the level of sensibility and given impotance to sensibility determination by populating slang, new words, emoticons and idiomatic expressions not in the system dictionary. It has considered the context through conjunctive adverbs fixed in korean characteristics which are free to the word order. It also recognize sensibility words such as TF(Term Frequency), RT(Retweet), Follower which are weighting factors of preference and has increased reliability of preference analysis considering weight on 'a very emotional tweet', 'a recognised tweet from users' and 'a tweeter influencer'

• Korean Journal of Radiology
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• 제22권8호
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• pp.1341-1351
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• 2021

Objective: To compare the quality of various polychromatic and monochromatic images with or without using an iterative metal artifact reduction algorithm (iMAR) obtained from a dual-energy computed tomography (CT) to evaluate total knee arthroplasty. Materials and Methods: We included 58 patients (28 male and 30 female; mean age [range], 71.4 [61-83] years) who underwent 74 knee examinations after total knee arthroplasty using dual-energy CT. CT image sets consisted of polychromatic image sets that linearly blended 80 kVp and tin-filtered 140 kVp using weighting factors of 0.4, 0, and -0.3, and monochromatic images at 130, 150, 170, and 190 keV. These image sets were obtained with and without applying iMAR, creating a total of 14 image sets. Two readers qualitatively ranked the image quality (1 [lowest quality] through 14 [highest quality]). Volumes of high- and low-density artifacts and contrast-to-noise ratios (CNRs) between the bone and fat tissue were quantitatively measured in a subset of 25 knees unaffected by metal artifacts. Results: iMAR-applied, polychromatic images using weighting factors of -0.3 and 0.0 (P_-0.3i and P_0.0i, respectively) showed the highest image-quality rank scores (median of 14 for both by one reader and 13 and 14, respectively, by the other reader; p < 0.001). All iMAR-applied image series showed higher rank scores than the iMAR-unapplied ones. The smallest volumes of low-density artifacts were found in P_-0.3i, P_0.0i, and iMAR-applied monochromatic images at 130 keV. The smallest volumes of high-density artifacts were noted in P_-0.3i. The CNRs were best in polychromatic images using a weighting factor of 0.4 with or without iMAR application, followed by polychromatic images using a weighting factor of 0.0 with or without iMAR application. Conclusion: Polychromatic images combined with iMAR application, P_-0.3i and P_0.0i, provided better image qualities and substantial metal artifact reduction compared with other image sets.

• 한국물환경학회지
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• 제29권4호
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• pp.504-513
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• 2013

Water quality trends for major tributaries (66 sites) in the Yeongsan River basin of Korea were examined for 12 parameters based on water quality data collected every month over a period of 12 months. The complex data matrix was treated with multivariate analysis such as PCA, FA and CA. PCA/FA identified four factors, which are responsible for the structure explaining 78.2% of the total variance. The first factor accounting 27.3% of the total variance was correlated with BOD, TN, TP, and TOC, and weighting values were allowed to these parameters for grade classification. CA rendered a dendrogram, where monitoring sites were grouped into 5 clusters. Cluster 2 corresponds to high pollution from domestic wastewater, wastewater treatment and run-off from livestock farms. For grade classification of tributaries, scores to 10 indexes were calculated considering the weighting values to 3 parameters as BOD, TN and TP which were categorized as the first factor after FA. The highest-polluted group included 10 tributaries such as Gwangjucheon, Jangsucheon, Daejeoncheon, Gamjungcheon, Yeongsancheon. The results indicate that grade classification method suggested in this study is useful in reliable classification of tributaries in the study area.

• 한국수자원학회논문집
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• 제50권12호
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• pp.827-836
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• 2017

하도홍수추적 방법에서 많이 사용되고 있는 Muskingum 방법의 가장 중요한 매개변수는 저류상수와 가중인자이다. Muskingum 방법은 상류유입지점에서 하류 유출지점까지 측방유입량이 고려되지 않지만, 실제 유역에는 강우로 인하여 측방유입유량이 발생한다. 이로 인해 상하류 실측자료를 이용하여 저류상수 및 가중인자를 산정하는 것이 매우 어려운 상황이다. 이에 본 연구는 HEC-RAS 1차원 부정류 해석모형을 이용한 수리학적 홍수추적을 통해 측방유입유량이 제외된 상태에서의 하도에서 전파되는 유량을 산정하였고, 이를 이용하여 저류상수 및 가중인자를 산정하는 방법을 제시하였다. 이와 함께 저류상수가 유하시간과 관계있음을 감안하여 국내 하천기본계획 수립 시 사용되는 유하시간 경험 공식들을 저류상수로 적용한 결과를 비교 분석하였다. 마지막으로 유량이 고려된 유하시간 산정 식을 개발하고, 유입량의 변화에 맞춰 유하시간을 업데이트하여 모의를 수행하는 방법을 제시하였다. 유량을 고려한 유하시간을 저류상수로 적용한 경우, 유량의 상승 및 하강 과정, 첨두 유량, 그리고 첨두 시간에 대해서 잘 모의하는 것으로 분석되었다.

• 한국지능시스템학회논문지
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• 제10권5호
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• pp.487-496
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• 2000

본 논문에서는, HCM 클러스러팅 방법과 유전자 알고리즘을 이용하여 다중 FNN 모델을 동정하고 최적화 한다. 제안된 다중 FNN은 Yamakawa의 FNN을 기본으로 하며, 퍼지 추론 방법으로 간략 추론을, 학습으로는 오류 역전파 알고리즘을 사용한다. 다중 FNN 모델의 구조와 파라미터를 동정하기 위해 HCM 클러스터링과 유전자 알고리즘을 사용한다. 여기서, 시스템 모델링을 위해 데이터 전처리 기능을 수행하는 HCM클러스터링 방법은 I/O 프로세서 공정 데이터를 이용하여 입출력 공간분할에 의한 다중 FNN 구조를 결정하기 위해 사용된다. 또한 유전자 알고리즘을 사용하여 멤버쉽함수의 정점, 학습율, 모멘텀 계수와 같은 다중 FNN 모델의 파라미터들을 동조한다. 모델의 근사화와 일반화 능력 사이에 합히적 균형을 얻기 위해 하중계수를 가진 합성 성능지수를 사용한다. 이 합성 성능지수는 근사화 및 예측 능력사이의 상호 균형과 의존성을 고려한 하중계수를 가진 합성 목적함수를 의미한다. 데이터 개수, 비선형성의 정도에 의존하는 이 합성 목적함수의 하중계수의 선택, 조절을 통하여 최적의 다중 FNN 모델을 설계하는 것이 유용하고 효과적임을 보인다. 제안된 모델의 성능 평가를 위하여 가스로 공정의 시계열 데이터와 비선형 함수의 수치 데이터를 사용한다.

• 전자공학회논문지B
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• 제33B권2호
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• pp.20-27
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• 1996

In this paper, we propose a coprime factor model reduction method to get a reduced order controller in $H^{\infty}$ mixed sensitivity problem with frequency weighting functions. for this purpose, the given $H^{\infty}$ mixed sensitivity problem is transformed into robust stabilization problem with coprime factor uncertainty of given plant. This method is to define frequency weighted coprime factors of plant in CSD (chain scattering description) form and reduce the coprime factors using weighted balanced truncation. then a controller is designed to the reduced order coprime factors using J-lossless coprime factorization method. Using this approach, the robust stability condition is derived and good performance is preserved in closed loop system with the given plant and the reduced order controller. Also the order of reduced controller for guaranteeing the robust stability can be determined before designing the reduced controller. The proposed method behaves well in both stable and unstable plant.

• 경영과학
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• 제11권3호
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• pp.153-167
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• 1994

Credibility theory has provided with a useful tool the assignment of weighting factor that reflects the credibility of the observed individual and collective experience to secure fair experience rate-,making. We review credibility models which can effectively estimate risk premiums using credibility theory, and suggest an empirical Bayed model based on the collective statistics to estimate the structural parameters. To illustrate the use of evolutionary models, the models are applied to the actual data, such as loss ratio, claim frequencies and severity, in the Korean automobile insurance. Also the possibilities of generalizations and applications of empirical models are discussed.