• 제목/요약/키워드: bimonthly data

검색결과 27건 처리시간 0.019초

시계열 자료의 분할에 관한 사례 연구 (A Study on the Disaggregation Method of Time Series Data)

  • 문승호;이정형
    • 디지털융복합연구
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    • 제12권6호
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    • pp.155-160
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    • 2014
  • 마케팅 자료를 입수하는 경우, 시장조사에 시간이 많이 소요되는 등의 이유로, 월간으로 입수하지 못하고, 2개월 간격으로 합산되거나 분기별로 합산된 자료만 입수할 수 있는 경우가 있다. 이러한 자료를 활용하여 월간으로 시장을 평가 혹은 예측하거나 마케팅 전략을 수립하여야 하는 경우, 격월 혹은 분기별로 합산된 자료를 월간 자료로 변환하여야 한다. 본 논문에서는 두 달 간격으로 합산되어 집계되는 자료를 월별 자료로 변환하는 여러 가지 방법을 소개한다. 이런 변환 방법에는 2개월간의 자료를 단순히 2로 나누는 단순평균법, 2개월간의 자료의 증감률을 월별 자료의 증감률에 그대로 적용하여 월별 자료로 변환하는 방법, 전문가의 판단에 따른 가중치를 적용하는 방법, 단순회귀모형 등의 모형을 정의하고 그 모형에 의해 월별 자료로 분해하는 방법 등이 있다. 본 논문에서는 유럽의 특정 국가의 가전제품 판매 사례를 활용하여, 두 달 간격으로 합산된 시장 자료를 월별 자료로 변환하는 모형을 활용한 방법을 소개하고자 한다. 나아가 이 모형을 활용하여 향후의 자료를 예측하는 방법도 소개한다.

1982-1983년.1997-1998년 엘니뇨현상 전후 한국동해역에서의 이상 저수온 현상 (Abnormal Cooling before and after the 1982-1983 and 1997-1998 ENSO Events in the Korean East Sea Water)

  • 홍철훈
    • 한국수산과학회지
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    • 제41권4호
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    • pp.294-300
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    • 2008
  • Abnormal cooling of the Korean East Sea Water(KESW) in the East Sea before and after the 1982-1983 and 1997-1998 ENSO events is examined using bimonthly routine observation data from the National Fisheries Research and Development Institute of Korea for the period 1965 to 2002. The KESW, which occupies roughly a region between the Korean Peninsula and west of approximately $131^{\circ}E$, showed extreme cold-state years(1981 and 1996) prior to the two strongest ENSO events of the last half-century. Inter-annual bimonthly mean anomalies at 100 m in the KESW region were $-3.10^{\circ}C\;and\;-3.41^{\circ}C(SD=1.4^{\circ}C)$ in 1981 and 1996, respectively. These results suggest that extreme cooling of the KESW may be a prelude to very strong ENSO events through large-scale teleconnections.

Long-term Environmental Changes: Interpretations from a Marine Benthic Ecologist's Perspective (II) -Eutrophication and Substratum Properties

  • Yoo Jae-Won;Hong Jae-Sang;Lee Jae June
    • Fisheries and Aquatic Sciences
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    • 제2권2호
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    • pp.210-217
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    • 1999
  • Chemical oxygen demand (COD), phytoplankton cell number and chlorophyll-a concentration (Chl-a), sediment mean grain size and ignition loss were studied to determine their temporal trends in the study area. Historical data of COD, cell number and Chl-a were gathered from the late 1960s or early 1980s to 1997, and trends in temporal domain were obtained from a simple regression. Sediments for grain size and ignition loss (as organic contents in sediments) were sampled from the Chokchon macrotidal flat bimonthly from September 1990 to November 1996, and were analyzed using the decomposition method of time series analysis. In general, the first three data showed increasing trends based on regression analysis. The trends of sediment grain size fluctuated in a neutral pathway while those of ignition loss yielded no increasing pattern. In contrast with the suggestions from Ahn and Choi (1998) who reported a coarsening variation in sediment grain size to be a cause of the directional and remarkable changes of macrofaunal communities in this area, we could not find such a corresponding variation pattern from our samples. In diagnosing eutrophication, a paradoxical phenomenon was encountered between the trends in water column (COD, cell number and Chl-a) and sediment (ignition loss) data. In this paper, we inferred the possible processes that produce the discrepancy. Some explanations and biological responses to eutrophication were predicted and discussed.

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인공위성 화상데이터를 이용한 북한 서해안지역의 미완공 간척지 조사 (Investigation on Ongoing Tideland Reclamation Projects in Western Coast of North Korea using Satellite Image Data)

  • 조병진;안기원
    • 한국농공학회지
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    • 제43권1호
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    • pp.75-86
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    • 2001
  • North Korea reported that tideland reclamation projects had been successfully constructed and/or under construction during the period of the third development scheme(1987∼1993), which were 28,400ha in 9 project areas: 8 projects along the western coast and one in the eastern coast. In this study eight projects located in western coast were investigated in order to confirm the detail of works, construction stages and difference from our project formulation methods using the topographic maps published in different years and the recent sattelite image data especially Lansat TM and SPOT PN. Intensity-hue-saturation (IHS) method was adopted to merge two sattelite data for the image enhancement of remote sensing. Construction stages of sea-dikes, land consolidation for paddy and salt pan, reservoir for irrigation and desalinization and the present land use were investigated and estimated the acreage of the development areas. The total gross project areas of 38,105 ha: 16,555 ha completed for paddy or salt pan, 16,826 ha under construction, and 4,724 ha under planning were confirmed, although the area of 27,100 ha in 8 projects were reported to be completed or ongoing on the bimonthly journal of N. Korean Trend published in 1994.

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기후변화에 따른 제주도 주변 해역 수산 어종 변화(1981-2010) (Multi-decadal Changes in Fish Communities Jeju Island in Relation to Climate Change)

  • 정석근;하승목;나한나
    • 한국수산과학회지
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    • 제46권2호
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    • pp.186-194
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    • 2013
  • We compiled and analyzed long-term time-series data collected in Korea to evaluate changes in oceanographic conditions and marine ecosystems near Jeju Island ($33^{\circ}00^{\prime}-34^{\circ}00^{\prime}\;N$, $125^{\circ}30^{\prime}-127^{\circ}30^{\prime}\;E$) from 1981 to 2010. Environmental data included depth-specific time series of temperature and salinity that have been measured bimonthly since 1961 in water columns at 175 fixed stations along 22 oceanographic lines in Korean waters by the National Fisheries Research & Development Institute, and time series of estimated volume transport of the Tsushima Warm Current (TWC) and Korea Strait Bottom Cold Water (KSBCW) for the period from 1961 to 2008. We analyzed the species composition in terms of biomass of fish species caught by Korean fishing vessels in the waters near Jeju Island (1981-2010). Data were summarized and related to environmental changes using canonical correspondence analysis (CCA). The CCA detected major shifts in fish community structure between 1982 and 1983 and between 1990 and 1992; the dominant species were a filefish during 1981-1992 and chub mackerel from 1992 to 2007. CCA suggested that water temperature and salinity in the mixed layer and the volume transport of the TWC and the KSBCW were significantly related to the long-term changes in the fish community in the waters off Jeju Island. Fish community shifts seemed to be related to the well-established 1989 regime shift in the North Pacific. Further studies are required to elucidate the mechanisms driving climate change effects on the thermal windows and habitat ranges of commercial species to develop fisheries management plans based on reliable projections of long-term changes in the oceanographic conditions in waters off Jeju Island.

Fresh water impact on chlorophyll a distribution at northeast coast of the Bay of Bengal analyzed through in-situ and satellite data

  • Mishra, R.K.;Senga, Y.;Nakata, K.
    • 대한원격탐사학회:학술대회논문집
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    • 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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    • pp.122-125
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    • 2006
  • The distribution of phytoplankton pigments were studied bimonthly at four stations from the mouth of Mahanadi River at Paradip to the 36.7km off coast in Bay of Bengal during April 2001 to December 2002. Bottom depth was shallower than 40m in all stations. The pigment concentration of Chl-a was measured. It increased from surface to bottom in the water column. The water column integrated chlorophyll-a concentration (Chl-a) varied between 6.1 and $48.5mg{\cdot}m-^2$ with peaks during monsoon period (Aug & Oct). Spatial distribution of salinity depended strongly on freshwater runoff. The salinity was 5psu at river mouth and 25.15psu at offshore in monsoon period; however it was 30psu at the river mouth in summer. We found a linear relationship between the amount of river discharge and integrated Chl-a in coastal region from 2 years observations. Extending this result, we analyzed rainfall and coastal Chl-a using satellite data. The relationship between the river discharge and monthly accumulated rainfall estimated from TRMM and others data sources was analyzed in 2001 and 2002 using Giovanni infrastructure provided by NASA. The result depended on the specified area on TRMM images; the river delta area had sharper relationship than wider rain catchments area. Moreover, the relationship between monthly averaged Chl-a derived from SeaWiFS and monthly accumulated rainfall estimated from TRMM was analyzed from 1998 to 2005. It was clear that the broom in monsoon period was strongly controlled by rainfall on river delta.

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멸치와 김 생산량 변동에 미치는 수온의 영향 (Effect of Temperature on Anchovy Catch and Laver Production in the Eastern Part of the South Sea of Korea)

  • 이충일;김현주
    • 한국환경과학회지
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    • 제16권8호
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    • pp.897-906
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    • 2007
  • Effect of seawater temperature (temperature) on the production of anchovy, Engraulis japonica and laver, Porphyra tenera Kjellman, were investigated in the eastern part of South Sea of Korea (ESS). Bimonthly temperature data (Feb., Apr., Jun., Aug., Oct., Dec.) from 1980 to 2002 were collected from Korean Oceanographic Data Center (KODC) and monthly anchovy catch and laver production from 1980 to 2002 were used from published sources by the Ministry of Maritime Affairs & Fisheries, Korea. Effects of temperature on the two organisms were examined in four cases. In case of lower anchovy catch and higher laver production (1993), temperature during main spawning season of anchovy was about $0.2-0.6^{\circ}C$ lower than normal condition, and temperature during seed collecting season of laver in Namhaedo, Kojedo went down below $22.0^{\circ}C$. In case of higher anchovy catch and higher laver production (1995), optimum temperature for catch was formed in main fishing ground, temperature for seed collection was lower than $22.0^{\circ}C$, In case of lower anchovy catch and lower laver production (1996), temperature for spawning and catch was about $0.6-1.6^{\circ}C$ lower than normal condition, and temperature during seed collection in nursery was about $0.5-1.0^{\circ}C$ higher than optimum temperature for seed collection. In case of higher anchovy catch and lower laver production (1998), temperature during main fishing and spawning season was about $1.0-1.8^{\circ}C$ higher than normal condition, and temperature during laver seed collection in nursery was $1.5^{\circ}C$ higher than optimum temperature for seed collection.

Monitoring and Analyzing Water Area Variation of Lake Enriquillo, Dominican Republic by Integrating Multiple Endmember Spectral Mixture Analysis and MODIS Data

  • Kim, Sang Min;Yoon, Sang Hyun;Ju, Sungha;Heo, Joon
    • Ecology and Resilient Infrastructure
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    • 제5권2호
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    • pp.59-71
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    • 2018
  • Lake Enriquillo, the largest lake in the Dominican Republic, recently has undergone unusual water area changes since 2001 thus it has been affected seriously by local community's livelihood. Earthquakes and seismic activities of Hispaniola plate tectonic coupled with human activities and climate change are addressed as factors causing the increasing. Thus, a thorough study on relationship between lake area changing, and those factors is needed urgently. To do so, this study applied MESMA on MODIS data to extract water area of Lake Enriquillo during 2001 and 2012 bimonthly, with six issues 12-year. MODIS provides high temporal resolution, and its coarse spatial resolution is compensated by MESMA fraction map. The increase in water area was $142.2km^2$, and the maximum lake area was $338.0km^2$ (in 2012). Water areas extracted by two Landsat scenes at two different times with three image classification approaches (ISODATA, MNDWI, and TCW) were used to assess accuracy of MODIS and MESMA results; it indicated that MESMA water areas are same as ISODATA's, less than 0.4%, while the highest difference is between MESMA and TCW, 2.4%. A number of previously formulated hypotheses of lake area change were investigated based on the outcomes of the present study, though none of them could fully explain the changes.

실버소비자들의 라이프스타일에 따른 의류제품과 미용서비스 구매행동 (The Elderly's Lifestyle and Their Purchasing Behavior of Apparel Products and Hairdressing Services)

  • 강은미;박은주
    • 한국의류학회지
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    • 제31권11호
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    • pp.1542-1553
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    • 2007
  • Recently, the growing of the aging population resulting from the medical and science development has made the elderly consumer as a new market. The purposes of this study were 1) to examine the purchase behavior of apparel products and hairdressing services of elderly consumers, 2) to investigate the purchase behavior in the apparel store and hairdressing shop on lifestyle types. Data were collected from 853 women in their 50s and 60s living in Busan. Data were analyzed by frequency analysis, descriptive analysis, factor analysis, Cronbach#s alpha, Chi-square analysis, cluster analysis, one-way ANOVA and Duncan test using SPSS WIN 12.0. The results of the study were as follows: First. when elderly consumers purchased apparel product, they were likely to use credit cards, to shop alone or with friends at a department store, and to use the store as information source. In their purchases of hairdressing services, they tended to visit the near shop for a permanent service bimonthly and to depend on their past experiences for hairdressing. Second, elderly consumers were classified by the lifestyle into the Active self-fidelitist, Economy family-oriented, and Passive-stagnant. The purchase behaviors in the apparel store and hairdressing shop were different among lifestyle types. Implications were suggested for the consumer behavior researchers and retailers of the elderly fashion market.

양식장 플랫폼을 활용한 실시간 해양환경 정보제공시스템 개발연구 (Development of Real-time Oceanographic Information System using Platforms of Aquaculture Farms)

  • 양준용;서영상;최용규;정규귀;정희동;박종수
    • 한국지리정보학회지
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    • 제10권2호
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    • pp.47-57
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    • 2007
  • 연안 해양환경의 급격한 변동에 의하여 매년 발생하고 있는 양식생물의 대량폐사의 원인을 규명하고 피해를 저감하기 위하여 양식장 플랫폼을 활용한 실시간 해양환경 정보제공시스템의 개발연구를 수행하였다. 일반적으로 실시간 관측시스템에 활용되고 있는 외양의 계류부이에 비해 관측정보가 직접 필요한 양식장에서 관측하여 제공함으로써 생산한 정보의 활용도가 높았으며, 양식장은 접근이 용이하고 상주인원이 있어 관측 장비의 유지보수가 유리한 점이 개발한 시스템의 특징이었다. 연속적 정보 수집을 위하여 관측치의 이상발생에 대한 긴급정비와 주기적인 예방정비 및 관측현황 모니터링을 시스템화하였으며, 과거 자료를 이용하여 통계적인 방법으로 구한 신뢰구간을 적용하여 관측 자료의 신뢰도 제고와 관측 중단을 최소화하도록 하였다. 또한 정보를 최종 이용자에게 효과적인 방법으로 전달하기 위하여 시스템의 개발내용에 홈페이지와 전자우편, 양식장의 현장에서 정보를 직접 확인할 수 있는 소형전광판과 어시장의 대형전광판을 통한 정보 제공체계를 구축하였다. 이를 통하여 어업인의 과학적인 어업활동을 지원하였고, 양식장 적지선정과 관련된 어장환경연구를 수행하였다. 양식생물의 대량폐사와 같은 경제적인 피해를 저감하며, 장기적으로 연안 해양환경의 변화와 이와 관련된 해양연구에 본 연구를 통한 기술개발의 결과를 활용할 수 있다.

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