• 수산경영론집
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• 제15권1호
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• pp.114-130
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• 1984

The structure of food demand is being changed according to the improvement of living standard. Moreover, the intake of animal protein is stepping up. This paper considers how much fresh-fish is consumed as source of animal protein and what extent fresh-fish have substitutive relation for meat with special reference to the change of income and price of fresh-fish and meat. And it is thought to be important work to estimate demand of fresh-fish in attemps to the prediction of food consume pattern and fishing industries in the future. For this estimation, the substitutive relation of fresh-fish and meat is essentially studied. The main conclusions of this study can be drawn as follows: 1. Fresh-fish and meat have substitutive relation on price axis. By the way, increase in demand of A (fresh-fish which have comparatively low price) can be expected according to the low of it's price against meat, but B (fresh-fish wihich have comparatively middle-high price) have peculiar demand without substitutive relation for meat. 2. Demand of A and B rise according to the income increases. 3. It is not sufficient to explain substutive relation of fresh-fish and meat without income variable. 4. Income increases bring about the more increase in demand of B than A. By the way, price increases bring about the decrease of it's consume expenditure, but A have fundamental demand as the source of animal protein. 5. In future, the intake of animal protein will step up. By the way, meat will occupy the more portion of the source of animal protein than fresh-fish.

• 산업경영시스템학회지
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• 제41권1호
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• pp.50-58
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• 2018

Intermittent demand is a demand with a pattern in which zero demands occur frequently and non-zero demands occur sporadically. This type of demand mainly appears in spare parts with very low demand. Croston's method, which is an initiative intermittent demand forecasting method, estimates the average demand by separately estimating the size of non-zero demands and the interval between non-zero demands. Such smoothing type of forecasting methods can be suitable for mid-term or long-term demand forecasting because those provides the same demand forecasts during the forecasting horizon. However, the smoothing type of forecasting methods aims at short-term forecasting, so the estimated average forecast is a factor to decrease accuracy. In this paper, we propose a forecasting method to improve short-term accuracy by improving Croston's method for intermittent demand forecasting. The proposed forecasting method estimates both the non-zero demand size and the zero demands' interval separately, as in Croston's method, but the forecast at a future period adjusted by binomial weight according to occurrence probability. This serves to improve the accuracy of short-term forecasts. In this paper, we first prove the unbiasedness of the proposed method as an important attribute in forecasting. The performance of the proposed method is compared with those of five existing forecasting methods via eight evaluation criteria. The simulation results show that the proposed forecasting method is superior to other methods in terms of all evaluation criteria in short-term forecasting regardless of average size and dispersion parameter of demands. However, the larger the average demand size and dispersion are, that is, the closer to continuous demand, the less the performance gap with other forecasting methods.

• Journal of the Korean Data and Information Science Society
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• 제26권4호
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• pp.885-894
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• 2015

전력시스템의 안정적이고 효과적인 운영을 위해선 전력수요예측이 필요하다. 본 연구에서는 일별전력수요패턴의 시간에 따른 커브를 군집분석 하려고 한다. 2009년 1월 1일부터 2011년 12월 31일까지의 일별 시간단위 전력수요 자료는 추세성분 제거와 로그변환을 통해 계절성분과 오차성분으로 구성된 시계열자료로 변환되었다. 변환된 자료는 Ma 등 (2006)이 제안한 함수적 군집모형을 사용하여 분석되었고, 모수는 EM알고리즘과 일반화교차검정을 통해 추정되었다. 군집의 수는 휴일과 평일을 잘 분류하는 10개로 결정하였다. 분석결과 월요일, 평일 (화요일~금요일), 토요일, 일요일 또는 공휴일과 계절요인으로 전력수요 평균곡선이 설명된다. 함수적 군집분석을 통한 전력수요패턴의 과학적인 분류는 향후 단기전력수요예측에 활용된다.

• 한국콘텐츠학회논문지
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• 제15권6호
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• pp.399-410
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• 2015

본 연구의 목적은 사회서비스 수요를 구성하는 이용자 수와 제공기관 수를 예측 할 수 있도록 시계열 모형을 활용하여 각각의 예측 값을 구성하고, 실제 관측된 값과의 차이를 확인하여 사회서비스분야에서 시계열 예측모형의 타당성을 검증하는 연구이다. 분석 자료는 한국보건복지정보개발원에서 발간한 사회서비스 제공기관 공급실태분석에서 제시된 발달재활서비스 이용 현황을 연구 목적에 따라 가공하여 이차 분석하였다. 분석결과 이용자 수는 ARIMA(1,1,0) 모형이, 제공기관 수는 ARIMA(0,1,1) 모형이 최적의 예측모형으로 제시되었다. 예측모형에 의한 예측 값은 관측 값과의 어느 정도 차이는 있었지만, 관측값은 예측값의 최대값과 최소값의 범위에 놓여 있었다. 따라서 사회서비스의 이용자를 활용한 수요예측과 제공기관을 활용한 공급예측의 모형구축에 대한 타당성은 가능할 수 있음을 확인할 수 있었다.

• Journal of the Korean Data and Information Science Society
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• 제28권2호
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• pp.395-406
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• 2017

전력 공급 시스템의 효율적인 운영을 위해 전력수요예측은 필수적이다. 본 연구에서는 군집분석과 분류분석을 이용하여 일 단위 시간별 전력수요량 시계열 패턴의 유형을 살펴보고자 한다. 전력거래소에서 수집된 2008년 1월 1일부터 2012년 12월 31일까지의 일 단위 시간별 전력수요량 데이터를 추세성분, 계절성분, 오차 성분으로 구성된 시계열 자료로 변환하여 사용하였다. 추세성분을 제거한 시계열 자료의 패턴을 구분하기 위한 군집 분석방법은 k-평균 군집분석 (k-means), 가우시안혼합모델 혼합 모델 군집분석 (Gaussian mixture model), 함수적 군집분석 (functional clustering)을 고려하였다. 주성분분석을 통해 24시간 자료를 2개의 요인로 축소한 후 k-평균 군집분석과 가우시안 혼합 모델, 함수적 군집분석을 수행하였다. 군집분석 결과를 토대로 2008년부터 2011년까지 총 4년간 데이터를 4가지 분류분석방법인 의사결정나무, RF (random forest), Naive bayes, SVM (support vector machine)을 통해 훈련시켜 2012년 군집을 예측하였다. 분석 결과 가우시안 혼합 분포기반 군집분석과 RF를 이용한 군집예측 결과의 성능이 가장 우수하였다.

• 수산경영론집
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• 제34권2호
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• pp.53-73
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• 2003

This paper is to analyze the past and present consumption pattern of fishes aquacultured in marine waters and thus to draw the policy direction to enhance the competitiveness of marine fish aquaculture in Korea. At present, the volume of meat consumption is surveyed to be more than that of marine fish, but it is revealed that fish consumption will become more increasing in the future according to the rise of the income. The survey shows that the consumption of fish is highest in the fall, and among the various patterns of consumption, live fish, so-called susi, is surveyed to be highly dominant. It is revealed that fish is enjoyed because of the special savor, diverse nutrients, and the prevention of adult diseases. Natural fish Is revealed to be more preferred to aquacultured one due to the sticky flesh quality and the low probability of the remained after the production process antibiotics, so that it is necessary to enhance the taste quality and make a clean cultivation to capture more market demand. Consumption of high-quality fish seems to become high in more than middle class and consumption of fish are estimated to increase in the future, more than that of meat if income level of the people increases. Also, if we try to make our high-quality fish become popular among the public and competible with the imported fish from abroad, it is recommended that they must lower production price by cost reduction and try to differentiate it by taste and environmental safety, etc. It was revealed that the significant factor in demand function for fish is income and it is almost the only factor affecting that demand. Also, it was revealed that the most significant factor affecting preference of fish is income and it Is almost the only factor affecting the preference. Therefore, we can ascertain that if proper goods can be distributed, demand for and preference of fish may increase according to the increase of income in the future.

• 한국정보통신학회논문지
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• 제22권4호
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• pp.587-594
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• 2018

본 연구는 LSTM기반의 전력수요 변동성 평가 시스템을 제안하고 핵심모듈인 수요예측모듈의 정확성을 증명하기 보다는 실제 전력수요 모니터링 시스템 내 딥러닝을 이용하여 갑작스러운 전력패턴의 변화를 인지할 수 있는 모듈에 대한 활용 가능성을 확인하고자 한다. 웹기반 시스템에 모듈로 적용하여 관리자가 전력사용 패턴의 변동성을 판단할 수 있도록 시각화된 보고서를 제공하였다. 변동성 평가시스템의 구현 결과 관공서와 병원 등의 기관의 경우 전력사용량 데이터가 일정한 형태의 패턴을 보임을 확인하였다. 반면 주거시설과 같이 전력사용량이 상대적으로 낮은 지역의 경우 변동성 평가에는 적절하지 않았음을 확인했다.

• 대한지역사회영양학회지
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• 제8권6호
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• pp.910-918
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• 2003

The purposes of this study were to develop a model for university foodservices and to provide management strategies for reducing costs, and increasing productivity and customer satisfaction. The results of this study were as follows : 1) The demands in university food services varied depending on the time series. A fixed pattern was discovered for specific times of the month and semesters. The demand tended to constantly decrease from the beginning of a specific semester to the end, from March to June and from September to December. Moreover, the demand was higher during the first semester than the second semester, within school term than during vacation periods, and during the summer vacation than the winter. 2) Pearson's simple correlation was done between actual customer demand and the factors relating to forecasting the demand. There was a high level of correlation between the actual demand and the demand that had occurred in the previous weeks. 3) By applying the stepwise multiple linear regression analysis to two different university food services providing multiple menu items, a model was developed in terms of four different time series(first semester, second semester, summer vacation, and winter vacation). Customer preference for specific menu items was found to be the most important factor to be considered in forecasting the demand.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2002년도 추계학술대회 논문집
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• pp.101-105
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• 2002

In a traditional hierarchical inventory system, direct orders are the only information for inventory management that is exchanged between the firms involved. But due to the rapid development of modern information technology, it becomes possible for the firms to share more information in real time, e.g. demand and inventory status data. And so the term Supply Chain has emerged because it is seen as an important source of competitive advantage. Now it is possible to challenge traditional approaches to inventory management. In the past, one of the de-facto assumptions for inventory management was that the demand pattern follows a specific distribution function. However, it is undesirable to apply this assumption in real situations because the demand information in the supply chain tends to be distorted due to the bullwhip effect in a supply chain. To overcome this weakness, we propose a new solution method using NN (Neural Network). Our method proceeds in three steps. First, we find the patterns of optimal reorder points by analyzing past data. Second. train the NN using these pattern data and finally decide the reorder point. Using simulation experiment, we show that the proposed solution method gives better result than that of traditional research.

• 전기학회논문지
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• 제61권12호
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• pp.1765-1773
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• 2012

The accuracy of load forecast is very important from the viewpoint of economical power system operation. In general, the weekdays' load demand pattern has the continuous time series characteristics. Therefore, the conventional methods expose stable performance for weekdays. In case of special days or weekends, the load demand pattern has the discontinuous time series characteristics, so forecasting error is relatively high. Especially, weekdays near the thanksgiving day and lunar new year's day have the mixed load profile characteristics of both weekdays and weekends. Therefore, it is difficult to forecast these days by using the existing algorithms. In this study, a new load forecasting method is proposed in order to enhance the accuracy of the forecast result considering the characteristics of weekdays and weekends. The proposed method was tested with these days during last decades, which shows that the suggested method considerably improves the accuracy of the load forecast results.