• 대한산업공학회지
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• 제39권5호
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• pp.361-366
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• 2013

Prediction of process parameters is very important in parameter design. If predictions are fairly accurate, the quality improvement process will be useful to save time and reduce cost. The concept of dual response approach based on response surface methodology has widely been investigated. Dual response approach may take advantages of optimization modeling for finding optimum setting of input factor by separately modeling mean and variance responses. This study proposes an alternative dual response approach based on machine learning techniques instead of statistical analysis tools. A hybrid neural network-genetic algorithm has been proposed for the purpose of parameter design. A neural network is first constructed to model the relationship between responses and input factors. Mean and variance responses correspond to output nodes while input factors are used for input nodes. Using empirical process data, process parameters can be predicted without performing real experimentations. A genetic algorithm is then applied to find the optimum settings of input factors, where the neural network is used to evaluate the mean and variance response. A drug formulation example from pharmaceutical industry has been studied to demonstrate the procedures and applicability of the proposed approach.

• 대한토목학회논문집
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• 제38권4호
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• pp.579-586
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• 2018

단기 통행속도 예측을 위해 데이터 기반 비모수적 기법들을 활용한 다양한 연구들이 수행되고 있다. 그럼에도 교통신호 및 교차로로 인한 복잡한 동적 특성을 가지는 도시부의 예측 연구는 상대적으로 부족한 실정이다. 본 연구는 도시부 통행 속도를 예측하기 위해 앙상블 경험적 모드 분해법(EEMD)과 인공신경망(ANN)을 이용한 하이브리드 접근법을 제안하는 것을 목적으로 한다. EEMD는 통행속도의 시계열 자료를 고유모드함수(IMF)와 오차항으로 분해한다. 분해된 IMF는 시간단위의 국지적 특성을 반영하며, ANN을 통해 개별적으로 예측된다. IMF는 원본데이터가 가진 비선형성, 비정상성, 진동 등의 복잡성을 완화하기 때문에, 원래의 통행속도에 비하여 더 정확하게 예측될 수 있다. 예측된 IMF들은 합산되어 예측 통행속도를 표현한다. 본 연구에서 제시된 방법을 검증하기 위하여 대구시의 DSRC로부터 구득된 통행속도 데이터가 활용된다. 성능평가는 도시부 링크 중 특히 예측이 어려운 지점에 대해 수행되었으며, 분석 결과 제시된 모형은 15분 후 예측에 대해 각각 평상시 10.41%, 와해상태시 25.35%의 오차율을 가지며, 단순 ANN 기법에 비하여 우수한 성능을 보이는 것으로 확인된다. 본 연구에서 개발된 모형은 도시교통관리체계의 신뢰성 있는 교통정보를 제공하는 데에 기여할 수 있을 것으로 기대된다.

• 한국수자원학회논문집
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• 제55권9호
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• pp.679-686
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• 2022

기후변화로 인한 돌발홍수의 발생 빈도 증가에 따라 X밴드 레이더를 이용한 보다 빠르고 정확한 강수 관측이 중요해지고 있다. 이에 환경부는 삼척과 울진에 2기의 이중편파 X밴드 레이더를 설치했다. 본 연구에서는 차폐 효과를 최소화하기 위해 설치된 2기의 각 레이더에서 2개의 고도각 관측을 수행한 뒤 얻어진 관측자료를 합성하여 정량강우를 산정하였다. 정량강우산정을 위해서 먼저 품질관리(QC) 기법을 적용한 뒤 비차등위상차(K_DP)를 산출하고 하이브리드 고도면 강수추정(HSR) 기법을 적용하였다. 본 연구에서는 산출된 K_DP를 이용해 R-K_DP 관계로 불리는 강우강도와 비차등위상차의 관계식을 적용하여 얻어지는 정량적 강우추정(QPE)의 정확도 상승을 위해 해당 관계식의 매개변수를 추정했다. 매개변수 추정을 위해서 여러 개의 강우량계와 레이더 자료를 바탕으로 경험적 방법을 개발하였다. 새로 제안된 매개변수를 이용한 관계식(R = 27.4K^0.81_DP)은 관측된 강수량에 대해 추정된 강수의 상관계수를 선행연구대비 1% 정도 약간 상승시켰다. 마찬가지로, 제곱평균 제곱근오차는 3.88 mm/hr에서 3.68 mm/hr로 감소했고 편차는 -1.72에서 -0.92로 상관계수보다 유의미하게 감소해 정확도가 상승했음을 보였다.

• 비파괴검사학회지
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• 제29권1호
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• pp.1-9
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• 2009

본 연구에서는 균열선단 주위의 응력장을 균열선단으로부터 멀리 떨어진 직선상에서 위상이동 광탄성법과 멱급수형 등각사상 맵핑함수를 이용하여 해석하였다. 해석된 광탄성 응력장을 실제의 광탄성프린지와 비교하였다. 정성적인 비교가 용이하도록 디지털 영상처리에 의해 등색프린지 패턴을 2배로 증식시키고, 증식된 프린지를 다시 세선 처리하여 서로 비교하였다. 정량적인 분석을 위하여 각각의 광탄성 측정 데이터와 계산된 프린지에 대한 퍼센트 오차와 멱급수형 응력함수의 항의 수에 따른 퍼센트 오차에 대한 표준편차를 비교하였다. 응력함수의 항의 수를 변화시켰을 때 표준편차를 계산하였다. 해석 결과 모드I 응력확대계수는 유한요소법과 경험식으로 계산한 값과 2% 이내로 근접하였다.

• 패션비즈니스
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• 제24권1호
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• pp.88-101
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• 2020

The music videos of BTS go beyond the limit of media promoting music and shows their meaning in various ways and complete the visual message of music through fashion style. BTS' fashion style in the music videos shows a change in symbolic representation of the genre of each album and song, of which gender images are changing aligned with the music messages of BTS. The purpose of this study was to derive gender images of fashion style in BTS music videos and to interpret their meaning based on Judith Butler's theory that performativity creates discourse through iterative process. It is conducted as a research method, an analytical study was conducted in parallel with literature studies and empirical case analysis. The scope of the study was limited to 301 costumes that appeared in 21 official music videos from debut single album '2Cool 4 Skool' released in 2013 to the mini album 'Map of the Soul: Persona' released in 2019. As a result of the analysis, the controversial fashion style, challenging fashion style, boyish fashion style, hybrid fashion style, the playful fashion style were revealed. The conclusion of studying the gender image of BTS, interpreted by this analysis using Judith Butler's theory, is as follows. The gender image of BTS is the traditional image that identifies with the dominant gender discourse, the resistive gender image that intentionally distances mainstream culture, the eclectic image parodying the gender of the opposing term, and the deconstructive image that transcends the dominant gender discourse.

• Geomechanics and Engineering
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• 제31권2호
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• pp.129-147
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• 2022

The properties of soil are naturally highly variable and thus, to ensure proper safety and reliability, we need to test a large number of samples across the length and depth. In pile foundations, conducting field tests are highly expensive and the traditional empirical relations too have been proven to be poor in performance. The study proposes a state-of-art Particle Swarm Optimization (PSO) hybridized Artificial Neural Network (ANN), Extreme Learning Machine (ELM) and Adaptive Neuro Fuzzy Inference System (ANFIS); and comparative analysis of metaheuristic models (ANN-PSO, ELM-PSO, ANFIS-PSO) for prediction of bearing capacity of pile foundation trained and tested on dataset of nearly 300 dynamic pile tests from the literature. A novel ensemble model of three hybrid models is constructed to combine and enhance the predictions of the individual models effectively. The authenticity of the dataset is confirmed using descriptive statistics, correlation matrix and sensitivity analysis. Ram weight and diameter of pile are found to be most influential input parameter. The comparative analysis reveals that ANFIS-PSO is the best performing model in testing phase (R² = 0.85, RMSE = 0.01) while ELM-PSO performs best in training phase (R² = 0.88, RMSE = 0.08); while the ensemble provided overall best performance based on the rank score. The performance of ANN-PSO is least satisfactory compared to the other two models. The findings were confirmed using Taylor diagram, error matrix and uncertainty analysis. Based on the results ELM-PSO and ANFIS-PSO is proposed to be used for the prediction of bearing capacity of piles and ensemble learning method of joining the outputs of individual models should be encouraged. The study possesses the potential to assist geotechnical engineers in the design phase of civil engineering projects.

• 한국음향학회지
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• 제39권4호
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• pp.351-363
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• 2020

발사체는 비행 중 공기역학적 현상에 기인하는 음향하중의 영향을 받는데, 특별히 천음속 영역에서 그 영향이 증가된다. 음향하중으로 인한 페어링 내부 소음진동은 탑재물의 오작동을 유발할 수 있어 이를 예측하고 저감하는 과정이 필수적이다. 본 연구에서는 발사체 외부에 작용하는 공기역학적 음향하중에 의한 페어링 내부 음향 진동환경을 예측하고, 음향 블랭킷과 헬름홀츠 공명기를 이용하여 소음저감 설계를 구현하는 프로세스를 개발하였다. 음향하중 예측은 Reynolds-Averaged Navier-Stokes(RANS) 유동해석 결과와 난류 경계층 내부 압력섭동에 관한 준 경험식을 이용하였고, 음향진동 연성해석은 ANSYS APDL과 VA One SEA의 Finite Element Statistical Energy Analysis(FE-SEA) 하이브리드 해법을 이용하였다. 개발된 절차를 천음속 해머 헤드형 발사체에 적용하여 음향하중 저감효과를 확인하고 개발된 절차의 유효성을 검증하였다. 본 연구에서 개발된 절차는 타당한 수준의 정확도로 신속한 결과를 얻을 수 있어 발사체 초기설계 단계에 유용하게 쓰일 수 있을 것으로 예상된다.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제10권7호
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• pp.191-198
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• 2021

분산 딥러닝은 각 노드에서 지역적으로 업데이트한 지역 파라미터를 동기화는 과정이 요구된다. 본 연구에서는 분산 딥러닝의 효과적인 파라미터 동기화 과정을 위해, 레이어 별 특성을 고려한 allreduce 통신과 연산 오버래핑(overlapping) 기법을 제안한다. 상위 레이어의 파라미터 동기화는 하위 레이어의 다음 전파과정 이전까지 통신/계산(학습) 시간을 오버랩하여 진행할 수 있다. 또한 이미지 분류를 위한 일반적인 딥러닝 모델의 상위 레이어는 convolution 레이어, 하위 레이어는 fully-connected 레이어로 구성되어 있다. Convolution 레이어는 fully-connected 레이어 대비적은 수의 파라미터를 가지고 있고 상위에 레이어가 위치하므로 네트워크 오버랩 허용시간이 짧고, 이를 고려하여 네트워크 지연시간을 단축할 수 있는 butterfly all-reduce를 사용하는 것이 효과적이다. 반면 오버랩 허용시간이 보다 긴 경우, 네트워크 대역폭을 고려한 ring all-reduce를 사용한다. 본 논문의 제안 방법의 효과를 검증하기 위해 제안 방법을 PyTorch 플랫폼에 적용하여 이를 기반으로 실험 환경을 구성하여 배치크기에 대한 성능 평가를 진행하였다. 실험을 통해 제안 기법의 학습시간은 기존 PyTorch 방식 대비 최고 33% 단축된 모습을 확인하였다.

• 간호행정학회지
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• 제5권1호
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• pp.63-76
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• 1999

The main objective of this study was to develop a concept of service marketing promotion in nursing that is derived from the concepts of service marketing theory. This research was a descriptive study, at the factor isolation level. The principle of concept derivation suggested by Walker and Avant (1988) and the Hybrid model suggested by Schwarz-Barcott and Kim (1993) were employed as the research method. The data were collected from December, 1997 to April. 1998 at a large general hospital located in Seoul. The procedures of this study were as follows: First. at the theoretical phase: the meaning, attributes, and definition of service marketing promotion were identified through an extensive review of the literature. Second, at the empirical phase: fieldwork was done to identify the promotional activities and events in nursing. Top nurse managers from 4 units (Director of Nursing, Head nurses of inpatient nursing unit, outpatient nursing unit. and home care nursing unit) were interviewed and the content of the interview was analyzed to identify the meaning and attributes of promotion in nursing. Other methods such as brochures and other audio-visual materials which were relevant to nursing promotion were used to supplement the interviews. Finally, the results of the theoretical and empirical analyses were intergrated to develop a concept of service marketing in nursing practice. A final definition of service marketing promotion in nursing was identified as follows. 1. Promotion as a marketing function in nursing service is concerned with communication to target markets on all information related to nursing service in order to satisfy the objectives of both a nursing service organization and the target markets. 2. The goals of nursing service promotion include: 1) increasing visibility of nursing services and delivering the information on nursing services, 2) affirming the value of nursing services, so it can contribute to formulation of reimbursement policy for nursing services. 3) advancing the general image of the nursing profession and nursing services. 4) achieving and attaining a desirable positioning for nurses among health care professionals. and 5) creating and stimulating the demand for nursing services. 3. In order to obtain these goals it is necessary to provide information on nursing services, to persuade target markets. to remind them about nursing services. and to establish a collaborative relationship with related departments. 4. The tools used to carry out the above functions of promotion in nursing are the providing nursing services, public relations and publicity. QA of nursing, advertising, and sales promotion. 5. The target markets of nursing service include the nursing customer markets. the internal markets, the influence markets. the recruitment markets. the supplier markets. and the nursing referral markets. In conclusion, the concept of promotion in other service marketing areas can be applied to the promotion of nursing service marketing. The promotion of nursing service is more than just effective communication in nursing service. it is the effective use of the concepts of service marketing promotion. Promotion of nursing service will contribute to create and expand nursing services.

• Steel and Composite Structures
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• 제34권5호
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• pp.743-767
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• 2020

Due to the impressive flexural performance, enhanced compressive strength and more constrained crack propagation, Fibre-reinforced concrete (FRC) have been widely employed in the construction application. Majority of experimental studies have focused on the seismic behavior of FRC columns. Based on the valid experimental data obtained from the previous studies, the current study has evaluated the seismic response and compressive strength of FRC rectangular columns while following hybrid metaheuristic techniques. Due to the non-linearity of seismic data, Adaptive neuro-fuzzy inference system (ANFIS) has been incorporated with metaheuristic algorithms. 317 different datasets from FRC column tests has been applied as one database in order to determine the most influential factor on the ultimate strengths of FRC rectangular columns subjected to the simulated seismic loading. ANFIS has been used with the incorporation of Particle Swarm Optimization (PSO) and Genetic algorithm (GA). For the analysis of the attained results, Extreme learning machine (ELM) as an authentic prediction method has been concurrently used. The variable selection procedure is to choose the most dominant parameters affecting the ultimate strengths of FRC rectangular columns subjected to simulated seismic loading. Accordingly, the results have shown that ANFIS-PSO has successfully predicted the seismic lateral load with R² = 0.857 and 0.902 for the test and train phase, respectively, nominated as the lateral load prediction estimator. On the other hand, in case of compressive strength prediction, ELM is to predict the compressive strength with R² = 0.657 and 0.862 for test and train phase, respectively. The results have shown that the seismic lateral force trend is more predictable than the compressive strength of FRC rectangular columns, in which the best results belong to the lateral force prediction. Compressive strength prediction has illustrated a significant deviation above 40 Mpa which could be related to the considerable non-linearity and possible empirical shortcomings. Finally, employing ANFIS-GA and ANFIS-PSO techniques to evaluate the seismic response of FRC are a promising reliable approach to be replaced for high cost and time-consuming experimental tests.