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        검색결과 237

        141.
        2000.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        경영활동에 있어서 직관력은 잘 알려진 인지능력이지만 효과적인 의사결정지원시스템의 개발 목적으로는 거의 고려되고 있지 않다. 본 연구는 의사결정자의 인지 유형에 따른 시계열 예측의 정확성과 뇌파의 차이를 통계적 검증, 인공신경망, 데이터 마이닝의 세 가지 접근방법으로 탐색하여 그 결과를 비교 분석함으로써 시계열 직관 예측에 영향을 주는 의사결정자의 인지적/생리적 특성을 도출함으로써 효과적인 의사결정환경을 조성하는데 공헌하고자 하였다. 실험결과 통계적 분석에서는 아무런 유의성을 찾을 수 없었으나, 인공신경망 분석에서는 인지유형과 감성유형이 모두 시계열 예측 정확도와 상관성이 있는 것으로 나타났으며, 데이터 마이닝 분석에서는 보다 의미 있는 상관관계를 찾아낼 수 있었다.
        4,800원
        142.
        2000.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this paper, sensor ring for antilock brake system was studied using the 400 series ferrite stainless steel powder. Because of more excellent corrosion resistance and mechanical characteristics than iron, sensor ring has been manufactured by P/M(Powder Metallurgy) method 400 series ferrite stainless steel. the results are following. 1, Compared with sensor ring made by iron, 400 series ferrite stainless steel has shown a good corrosion resistance without an addition surface treatment. thus the decreasing production process has been obtained. 2. The products before sintering are much more corrodible in the condition of spray test of salt water and ammonia than humidity and nitrogen condition.
        4,600원
        144.
        2000.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is concerned with finding the global optimal solutions for the redundancy optimization problems in series-parallel systems related with system safety. This study transforms the difficult problem, which is classified as a nonlinear integer problem, into a 0/1 IP(Integer Programming) by using binary integer variables. And the global optimal solution to this problem can be easily obtained by applying GAMS (General Algebraic Modeling System) to the transformed 0/1 IP. From computational results, we notice that GA(Genetic Algorithm) to this problem, which is, to our knowledge, known as a best algorithm, is poor in many cases.
        4,200원
        145.
        1999.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        투과증발 공정을 이용한 알코올/물 혼합물의 분리 시 투과성분/투과성분, 투과성분/막간의 상호인력이 전체적인 투과거동에 어떠한 영향을 미치는지 연구하였다. 사용한 막은 poly(vinyl alcohol)을 glutaraldehyde 로 가교한 막을 사용하였다. 일련의 알코올은 분자량 크기 순서대로 methanol, ethanol, 1-propanol, 1-butanol을 사용하였으며, 조성은 70~97 wt% , 온도는 30, 40, 5℃로 변화시키면서 실험하였다. 투과속도는 알코올 함량이 높은 영역에서는 methanol 수용액이 가장 높았으며 ethanol, 1-propanol, 1-butanol 수용액 순으로 감소하였다. 그러나 물의 함량이 어느 정도 높아지면 이런 현상은 완전히 역전되어 1-butanol 수용액의 투과속도가 가장 높으며 1-propanol, ethanol, methanol 수용액 순으로 투과속도 크기를 보였다. 이러한 현상을 공급액의 조성에 따른 막과 투과성분간의 상호인력, 투과성분과 투과성분간의 상호인력 등의 영향의 관점에서 분석하였다.
        4,000원
        146.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 인지 유형에 따라 시계열 예측의 정확성이 분석적인 사람과 직관적인 사람 간에 다를 것이란 가설을 설정하고 이를 규명하기 위하여 44명의 대학생을 사용하여 실험이 이루어졌다. 피험자는 MBTI에 의거하여 분석적인 그룹과 직관적인 그룹으로 나누고 주어진 시계열 데이터에 대하여 예측을 하게 하였다. 이때 인지 유형에 따른 뇌파의 편측성을 분석하기 위하여 전두엽에서 뇌파(F3, F4)를 측정하였다. 그 결과, 인지유형간의 뇌파의 편측성에 유의적인 차이가 없었으며, 예측의 정확성 (MAPE) 또한 유의적인 차이가 없었다.
        4,000원
        147.
        1999.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        EEG 생리신호의 분석은 국내에서도 최근에 활발하게 연구가 진행되고 있으나, 시계열을 이용한 분석법은 통계학의 전문적인 지식을 요구하고 있기 때문에 연구에 많은 어려움이 있다. 그러므로 감성과학 연구자들이 보다 쉽게 이해하고 분석할 수 있는 Tool의 개발이 절실히 요구되고 있다. 본 논문에서는 EEG 생리신호 분석을 위한 모형분석 시스템과 생리신호 분류를 위한 판별분류 시스템을 구축하였다. 이 시스템에서는 신호분석을 위한 그래프 작성, 자극 신호에 대한 모형식별 방법의 제시, 모형에 대한 추정 및 진단 기준에 따른 최적의 모형선정 방법 등을 지원한다. 또한 선정된 모형에 이해 모수를 추정하고 이를 이용하여 통계에 대한 지식이 없이도 쉽게 각 뇌파 신호들을 판별 분류할 수 있다.
        4,000원
        148.
        1998.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        시계열 예측은 효과적인 기업 경영에 반드시 필요한 활동이지만, 이와 관련 인간의 인지처리 과정에 대한 연구는 아직까지 미비하다. 본 연구는 인간 감성이 시계열 예측에 미치는 영향을 탐색하였다. 본 실혐에서는 반복을 통한 2(감성) x 2(횟수) 팩토리얼 설계를 채택하였다. 감성은 청각, 시각, 후각자극을 통해 환경을 조성하고 준비된 시나리오를 연상케하여 유발시켰다. 12명의 대학, 대학원생이 실험에 참여하였으며, 감성의 영향을 탐색하기 위해 뇌파(EEG)와 피부저항(GSR)이 후두엽(Oz)과 전두엽(Fz)에서 측정되었다. 그 결과 인간의 감성은 예측에 유의적인 영향을 보였다. 즉, 피험자가 부정적인 감성을 갖을 때 긍정적인 감성에 비해 예측의 정확성이 높은 경향이 있었다. 그 이유는 부정적 감성일 경우 전두엽에서 베타가 많이 출현하였고, 이는 시계열 예측의 정확도를 향상시키는 역할을 하였다.
        4,200원
        149.
        1996.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Forecasts of monthly landings of walleye pollock, Theragra chalcogramma, in Korea were carried out by the seasonal Autoregressive Integrated Moving Average(ARlMA) model. The Box - Cox transformation on the walleye pollock catch data handles nonstationary variance. The equation of Box - Cox transformation was Y'=(Y0.31 1)/0.31. The model identification was determined by minimum AIC(Akaike Information Criteria). And the seasonal ARlMA model is presented (1- O.583B)(1- B1)(l- B12)Zt =(l- O.912B)(1- O.732B12)et where: Zt=value at month t ; Bp is a backward shift operator, that is, BpZt=Zt-P; and et= error term at month t, which is to forecast 24 months ahead the walleye pollock landings in Korea. Monthly forecasts of the walleye pollock landings for 1993~ 1994, which were compared with the actual landings, had an absolute percentage error(APE) range of 20.2-226.1 %. Thtal observed annual landings in 1993 and 1994 were 16, 61OM/T and 1O, 748M/T respectively, while the model predicted 10, 7 48M/T and 8, 203M/T(APE 37.0% and 23.7%, respectively).
        4,000원
        151.
        1992.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Generally a navigator evaluated the maneuverability of his ship by the scale of turning circle which was described only by the largest rudder angle of the port and starboard sides. But to have the sufficient knowledge of his ship's maneuvering characteristics he should consider the data about the new course keeping test, the spiral test, and the turning circle tests in accordance with the rudder angles together. In this paper the author performed the above tests to study the maneuverability of the stern trawler M.S. Pusan 404 which is a training ship of the National Fisheries University of Pusan. The obtained results are summarized as follows: 1. When the rudder angles being 5。, 10。, 20。, 30。, 35。 the advances of the starboard side turning circles were 12.8, 8.2, 4.8, 2.9, 2.7 times as large as the length of the ship, and of the port side turning circles were 13.3, 8.7, 5.4, 3.5, 2.9, time as large as the large as it. Under the same conditions the tactical diameters were 15.1, 9.7, 5.2, 3.1, 2.8 times as large as the length of the ship, for starboard side, and 17.2, 12.4, 6.4, 3.7, 3.2 times as large as it for port side. 2. As the rudder angle being increased the ratio of the advance to the tactical diameter was nearly 1 and her obeying ability was better than that of the small angle. 3. The mean values of the rates of speed reduction during the steady turning motion were 0.96, 0.92, 0.82, 0.71, 0.65 in accordance with the rudder angles. 4. The relative formulas between the distance to the new course y and the altering course x were as follows: When rudder angles being 10。, 20。, 30。, y=52.2222+1.6133x, y=48.750+0.9383x, y=39.250+0.655x respectively. 5. There was little difference of the distance to the new course between rudder angle 20。and 30。, and so it is desirable for a navigator to a navigator to use the small rudder angles unless sudden emergencies. 6. Though her rudder angle being small her course stability was good according to the spiral tests.
        4,000원
        154.
        2021.10 KCI 등재 서비스 종료(열람 제한)
        This study analyzes structural landscape changes over a time-series for a small and medium-sized city, Gangneung-Si, based on area and distribution patterns, and according to the type of land cover. Among the types of land cover, the area ratio of urbanized areas increased by 2.02% in the late 2010s as compared to the late 1980s, while there was a decrease of 2.69% in farmland and 0.69% in grassland areas. On analyzing the changes in land cover use by applying the Fragstats program, it was confirmed that landscape changes in urban and management areas were relatively severe according to the Landscape Shape Index, Largest Patch Index, and Aggregation Index. A pattern of concentrated expansion was also found around certain areas. In particular, from the analysis, it was established that the proportion of urbanized area had considerably increased and that the extent of farmland damage to management areas, including planned management areas, was large. Additionally, the Total Core Area generally indicated a reduction in the core areas of farmland and forest within urban and management areas. A medium-sized city showed significant changes besides large cities in terms of landscape structure. The developmental pressure on management areas, in particular, was quite high.
        155.
        2021.07 KCI 등재 서비스 종료(열람 제한)
        We used seawater temperature data, measured in the Garolim Bay, to analyze temperature variation on an hourly and daily basis. Lagrange’s interpolation using before and after data was applied to restore nonconsecutive missing temperature data. The estimated error of the data restoration was 0.11oC. Spectral analyses of seawater temperature showed significant periodicities of approximately 12.4 h (semidiurnal tide) and 15.0 d (long-period tide), which is close to those of M2 and Mf partial tides. Variation in seawater temperature was correlated more with tidal height than with air temperature around the Garolim Bay. In June and December, when the seawater temperature difference between the inside and outside of the Garolim Bay was very large, the periodicities of 12.4 h and 15.0 d were highly prominent. These results indicate that the exchange of seawater between the inside and outside of the Garolim Bay induced variations in seawater temperature owing to tide. Understanding temperature variation because of tide helps to prevent abnormal mortality of cultured fish and to predict seawater temperature in the Garolim Bay.
        156.
        2021.03 KCI 등재 서비스 종료(열람 제한)
        This study was undertaken to find out national level changes in area, production and yield of two major staple crops wheat and potato in Bangladesh. The time series of secondary data was collected from yearbook of agricultural statistics under Bangladesh Bureau of Statistics (BBS) and used for the statistical analysis during the thirty-year period of 1989/90-2018/19. Moreover, selected data were divided into two groups and regarded as segment (1989/90-2003/04, 2005/06-2018/19) to examine the significant level in each crop. The results of different statistical techniques showed that wheat cultivated area and production were satisfactory level but yield was not too much standard in context of country demand. In the case of potato, yield as well as cultivated area and production were crossed the significant level and fulfilled the demand of population. In recent few years, the ratio of potato production rapidly increased, compared with the cultivation area. Based on segment (period) analysis, at the first half wheat production was always below, compared with the area but second half nine years saw slightly improved. On the other hand, in both segment potato growth rate in area, production and yield were increased throughout the study period. The highest instability was also shown in area, production and yield of potato during whole as well as segmented period. There was always a positive relationship between country’s demand and supply. Both wheat and potato are considered as staple crops and based on the productive capability over cultivated area, potato showed the higher productivity for the country of Bangladesh. In consequences, potato consuming demand also rapidly increased all over the country, compared with past respectively.
        157.
        2020.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The present study aims to investigate the impact of tourism growth on human development in Indian economy. For this purpose, the study uses annual data from 1980 to 2018 and utilizes two proxies for tourism growth – tourism receipt and tourist arrivals – and uses human development index calculated by UNDP. The study uses control variables such as government expenditure and trade openness. The study employs auto regressive distributed lag (ARDL) approach to investigate the cointegrating relationship among the variables in the model. Further, the study also explores the causal nexus between tourism sector and human development by using the Toda-Yamamoto Granger non-causality test. The result of ARDL bounds test reveals the existence of cointegrating relationship between human development indicators, government expenditure, trade openness, and tourism sector growth. The cointegating coefficient confirms a positive and significant relationship between tourism sector growth and human development in India. The causality result suggests that economic growth and tourism have a positive impact while trade openness has a negative impact on human development in India. The major findings of this study suggest that tourism plays an important role in the socio-economic development of Indian economy in recent years and the country must develop this sector to achieve sustainable development.
        158.
        2020.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study investigates the problem of outlier detection based on discrete wavelet transform in the context of time series data where the identification and treatment of outliers constitute an important component. An outlier is defined as a data point that deviates so much from the rest of observations within a data sample. In this work we focus on the application of the traditional method suggested by Tukey (1977) for detecting outliers in the closed price series of the Saudi Arabia stock market (Tadawul) between Oct. 2011 and Dec. 2019. The method is applied to the details obtained from the MODWT (Maximal-Overlap Discrete Wavelet Transform) of the original series. The result show that the suggested methodology was successful in detecting all of the outliers in the series. The findings of this study suggest that we can model and forecast the volatility of returns from the reconstructed series without outliers using GARCH models. The estimated GARCH volatility model was compared to other asymmetric GARCH models using standard forecast error metrics. It is found that the performance of the standard GARCH model were as good as that of the gjrGARCH model over the out-of-sample forecasts for returns among other GARCH specifications.
        159.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        Extreme low temperature has various effects on society. It has negative impacts on health, industry, agriculture, and transportation during winter season. Therefore, extreme low temperature is recognized as main factor that causing traffic accidents. This study analyzed the relationship between low temperature and traffic accidents from 2012 to 2018. This study also compared the differences in vulnerability to low temperature between urban and rural areas. Generalized Additive Model (GAM) and Poisson regression model are used to estimate the thresholds and the level of traffic accidents. The results show that the thresholds tend to be decreased gradually, but the level of traffic accidents are more likely to increase in both urban and rural areas Comparatively, rural areas are more vulnerable to traffic accident caused by drop in temperature than urban areas.
        160.
        2020.11 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The dynamics of communications powered by the Internet, specifically from the increased use of social media, has led marketers to find creative channels to engage with the customers. One of the recent channels, “branded entertainment”, is becoming familiar as an advertising strategy in which the content presented is a marketing tool for the advertising of certain brands. The current study examined the case of a branded-entertainment channel and the mechanism of the advertising instrument that leads to purchase intention. The specific purpose of this research is to investigate whether there is evidence of the role of narrative transportation and the fantasy proneness leading towards purchase of the brand advertised. To arrive at the conclusion, the study using web series sponsored by an artificial sweetener brand and employs a quantitative survey to question the audience. The findings contribute toward the understanding of how consumers respond to branded entertainment via video-sharing platforms. It is indicated that the stories presented in the web series can stimulate the audience to fantasize. Thus, the advertising message conveyed through narrative persuasion can form a favorable attitude toward the brand, which leads to intention to purchase. Practical elements are identified along with limitations and future research suggestions.