• Title/Summary/Keyword: e-Community

Search Result 1,663, Processing Time 0.04 seconds

Conceptualization of an SSI-PCK Framework for Teaching Socioscientific Issues (과학기술 관련 사회쟁점 교육을 위한 교과교육학적 지식(SSI-PCK) 요소에 대한 탐색)

  • Lee, Hyunju
    • Journal of The Korean Association For Science Education
    • /
    • v.36 no.4
    • /
    • pp.539-550
    • /
    • 2016
  • The purpose of the study is to conceptualize SSI-PCK by identifying major components and sub-components to promote science teachers' confidence and knowledge on teaching SSIs. To achieve this, I conducted extensive literature reviews on teachers' perceptions on SSI, case studies of teachers addressing SSIs, SSI instructional strategies, etc. as well as PCK. Results indicate that SSI-PCK include six major components: 1) Orientation for Teaching SSI (OTS), 2) Knowledge of Instructional Strategies for Teaching SSI (KIS), 3) Knowledge of Curriculum (KC), 4) Knowledge of Students' SSI Learning (KSL), 5) Knowledge of Assessment in SSI Learning (KAS), and 6) Knowledge of Learning Contexts (KLC). OTS refers to teachers' instructional goals and intentions for teaching SSIs. Teachers often present a) activity-driven, b) knowledge and higher order thinking skills, c) application of science in everyday life, d) nature of science and technology, e) citizenship and f) activism orientations for teaching SSIs. KIS indicates teachers' instructional knowledge required for effectively designing and implementing SSI lessons. It includes a) SSI lesson design, b) utilizing progressive instructional strategies, and c) constructing collaborative classroom cultures. KC refers to teachers' knowledge on a) connection to science curriculum (horizontal/vertical) and b) connection to other subject matters. KSL refers to teachers' knowledge on a) learner experiences in SSI learning, b) difficulties in SSI learning, and c) SSI reasoning patterns. KAS indicates teachers' knowledge on a) dimensions of SSI learning to assess, and b) methods of assessing SSI learning. Finally, KLC refers to teachers' knowledge on the cultures of a) classrooms, b) schools, and c) community and society where they are located when teaching SSIs.

Change in the Microbial Profiles of Commercial Kimchi during Fermentation (국내 시판김치의 김치담금부터 숙성까지의 미생물 균총 변화)

  • Chang, Ji-Yoon;Choi, Yu-Ri;Chang, Hae-Choon
    • Food Science and Preservation
    • /
    • v.18 no.5
    • /
    • pp.786-794
    • /
    • 2011
  • To investigate the sanitary-quality level of commercial kimchi in South Korea, the pH, acidity, and microbial-flora changes in the kimchi were determined. Samples of kimchi produced by three different manufacturers (a small grocery store, a small/medium-sized enterprise, and a large food company) were collected. Freshly made kimchi was purchased and fermented at $10^{\circ}C$ for 10 days. The pH of the commercial kimchi on the purchased day was approximately pH 5.8, and that on the $10^{th}$ day of fermentation was ${\simeq}pH$ 4.1. The kimchi purchased from a large company showed a more rapid decline in pH level during fermentation. The saltiness of the kimchi purchased from a medium-sized company was slightly higher than those of the other commercial kimchi samples. The saccharinity index of the kimchi produced by a small grocery store was higher than those of the other samples, and its value deviation was also higher than those of the other commercial kimchi samples. A higher total viable-cell count and a higher lactic-acid bacteria (LAB) count were detected in the kimchi from the large food company at the beginning of fermentation compared to the samples of the two other kimchi manufacturers. The highest cell numbers of gram-positive bacteria (except LAB) and coliform bacteria were detected from the small-grocery-store kimchi, but the coliform bacteria count gradually decreased during fermentation although such bacteria were still detected until the $10^{th}$ day of fermentation. In contrast, coliform bacteria were not detected in the samples from the medium-sized and large food companies. Yeast, which is detected in over-ripened kimchi, was detected in the unfermented kimchi from the small grocery store, which had a below-0.36% acidity level. The gram-positive bacteria (except LAB) that were detected in all the tested commercial kimchi samples were determined to be Bacillus spp., and the gram-negative bacteria were determined to be Escherichia coli, Enterobacter spp., Sphingomonase spp., and Strenophomonas spp. The proportions of all the aforementioned bacteria in the kimchi samples, however, were different depending on the samples that were taken. These results indicate that a more sanitary kimchi production process and a more systematic kimchi production manual should be developed to industrialize and globalize kimchi.

Distribution Dynamics of Fish Community in Shallow Wetland by Environmental Variables (얕은 습지에서 환경 요인에 따른 어류상 분포 특성)

  • Choi, Jong-Yun;Jo, Hyunbin;Kim, Seong-Ki;La, Geung-Hwan;Joo, Gea-Jae
    • Korean Journal of Environment and Ecology
    • /
    • v.29 no.3
    • /
    • pp.391-400
    • /
    • 2015
  • In order to investigate the distribution and species composition of fish in shallow wetlands that might be affected by environmental factors, we investigated the physicochemical parameters, macrophytes biomass, and fish assemblage in 24 shallow wetlands in South Korea from May to June, 2012. In this study, a total of 20 fish species were identified, and Cypinidae were found to be the most dominant species. Physicochemical parameters and macrophyte biomass were different in the survey sites, and macrophytes biomass, in particular, showed a positive relationship with fish abundance in stepwise multiple regression (df=1, F=32.00, P=0.001). According to the result of the cluster analysis between survey sites, the survey sites were divided into three groups in accordance with species composition of fish in relation to macrophytes biomass. In the wetlands of the first group, Lepomis macrochirus which belongs to Centrarchidae was found to be dominant and other fish assemblages were hardly seen. In the second group, unlike the first group, Carassius auratus that belongs to Cypinidae was found to be dominant. In the third group, Lepomis macrochirus was found to be as dominant as the first group but various other fish species appeared. Where there was abundance of the main food sources (i. e. zooplankton) of fish in the survey sites, there were more diverse macrophyte biomass. Consequently, it is proven that macrophytes strongly affect the species composition and abundance of fish, and high biomass of macrophytes support high assemblage of fish. Based on these results, we recommend establishing diverse aquatic macrophytes communities when restoring or creating wetlands to assure high diversity of fish species that use macrophytes as their habitat.

Projecting future hydrological and ecological droughts with the climate and land use scenarios over the Korean peninsula (기후 및 토지이용 변화 시나리오 기반 한반도 미래 수문학적 및 생태학적 가뭄 전망)

  • Lee, Jaehyeong;Kim, Yeonjoo;Chae, Yeora
    • Journal of Korea Water Resources Association
    • /
    • v.53 no.6
    • /
    • pp.427-436
    • /
    • 2020
  • It is uncertain how global climate change will influence future drought characteristics over the Korean peninsula. This study aims to project the future droughts using climate change and land use change scenarios over the Korean peninsula with the land surface modeling system, i.e., Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro). The Representative Concentration Pathways (RCPs) 2.6 and 8.5 are used as future climate scenarios and the Shared Socio-economic Pathways (SSPs), specifically SSP2, is adopted for the land use scenario. The using Threshold Level Method (TLM), we identify future hydrological and ecological drought events with runoff and Net Primary Productivity (NPP), respectively, and assess drought characteristics of durations and intensities in different scenarios. Results show that the duration of drought is longer over RCP2.6-SSP2 for near future (2031-2050) and RCP8.5-SSP2 (2080-2099) for the far future for hydrological drought. On the other hand, RCP2.6-SSP2 for the far future and RCP8.5-SSP2 for the near future show longer duration for ecological drought. In addition, the drought intensities in both hydrological and ecological drought show different characteristics with the drought duration. The intensity of the hydrological droughts was greatly affected by threshold level methods and RCP2.6-SSP2 for far future shows the severest intensity. However, for ecological drought, the difference of the intensity among the threshold level is not significant and RCP2.6-SSP2 for near future and RCP2.6-SSP2 for near future show the severest intensity. This study suggests a possible future drought characteristics is in the Korea peninsula using combined climate and land use changes, which will help the community to understand and manage the future drought risks.

A Case Study on High and Low Performance Areas for Family Planning (가족계획 우수.부진지역 사례연구)

  • 홍성열;김태일
    • Korea journal of population studies
    • /
    • v.4 no.1
    • /
    • pp.105-130
    • /
    • 1981
  • This study was conducted to compare the characteristics of high performane areas for family planning with that of low performance areas and to find factors which strongly affected contraceptive practice behavior. For the study, eight areas were selected from 274 rural family planning canvassing areas of Korean Population Policy and Program Evaluation Study, which was an action study operated in all areas of Cheju Island from July 1, 1976 until December 31,1979. As a first step of the action study, Cheju Island was devided up 318 family planning canvasser areas Each area was consisted of 200 households in rural district and 300 households in urhan one Duriog the period of project, each canvassing area had been managed by a female family planning canvasser, selected by director of health center considering several individual conditions needed for family planning activities Basic activities of canvassers were to counsell all the eligihie couples in own charged area about family planning methods and also to distribute contraceptives such as condoms and oral pills. In case couples desire to accept sterilization including vasectomy and tubal-ligation, the canvassers played a linking role connecting potential client with family planning field workers. Canvassng areas shows significant differentce in performance for family planning, nevertheless they are supposed to have almost the same conditions regarding family planning distribution channel. Because the purpose of the Cheju project was to eliminate all the problems that existed in governmental distribution system, that is to remove geographic, economic, cognitive and administrative barriers Accumulated performances of family planning methods accepted by residents in each area were calculated by eligible women aged 14-49. And then canvassing areas were ranked according to performance score. Consequently, 4 areas in extremely high and low family planning performance areas were selected respectively. Major results were obtained by comparing characteristics of high performance area with that of low performance areas, which are as follows: 1. The mean number of living children was about the same both in high and low performance areas for family planning. But respondents' mean age (38.5) in high performance areas was higher than that (37.0) in low performance areas 2. Respondents' perception in the expectant educational level of others' children in high performance areas was higher than that in low performance areas, although respondents educational level, monthly expenditure and ratio of children in high school and above was not different. 3. Ratio of ownerships of TV and newspaper in high performance areas was highen than that in low performance areas 4. The duration of canvasser' charge in high performance areas was longer than that of low performance areas, showing the fact that canvassers didn't move cut in high performance areas 5. In high performance areas, canvassers' houses were relatively located in the center part of the village. And so villagers resided in near distances from the anvasser's house 6. 4H clubs' activities in high performance areas were more active than those in low performance areas Therefore it was assumed that cohesiveness of community in high performance areas were stronger than that in low areas. 7. Canvassers' family planning practice rate was higher than that in low performance areas, and also canvassers' human relationship was more sociable than that of canvassers in low performance areas. 8. Fourteen variables which showed relatively high significance level in $X^2$ and F test were selected as independent variables for stepwise regression analysis. According to the results of regression analysis. five of 14 variables-distributors education level ($R^2$=.4439), duration of distributor's charge ($R^2$=.6166), 4H club activities ($R^2$=.6697), canvasser's contraceptive practice ($R^2$=.7377) and location of distributions house ($R^2$=.8010) explained 80.1 percent of total variance.

  • PDF

Groundwater Flow Analysis in Fractured Rocks Using Zonal Pumping Tests and Water Quality Logs (구간양수시험과 수질검층자료에 의한 균열암반내 지하수 유동 분석)

  • Hamm, Se-Yeong;Sung, Ig-Hwan;Lee, Byeong-Dae;Jang, Seong;Cheong, Jae-Yeol;Lee, Jeong-Hwan
    • The Journal of Engineering Geology
    • /
    • v.16 no.4 s.50
    • /
    • pp.411-427
    • /
    • 2006
  • This study aimed to recognize characteristics of groundwater flow in fractured bedrocks based on zonal pump-ing tests, slug tests, water quality logs and borehole TV camera logs conducted on two boreholes (NJ-11 and SJ-8) in the city of Naju. Especially, the zonal pumping tests using sin91e Packer were executed to reveal groundwater flow characteristics in the fractured bedrocks with depth. On borehole NJ-11, the zonal pumping tests resulted in a flow dimension of 1.6 with a packer depth of 56.9 meters. It also resulted in lower flow dimensions as moving to shallower packer depths, reaching a flow dimension of 1 at a 24 meter packer depth. This fact indicates that uniform permissive fractures take place in deeper zones at the borehole. On borehole SJ-8, a flow dimension of 1.7 was determined at the deepest packer level (50 m). Next, a dimension of 1.8 was obtained at 32 meters of packer depth, and lastly a dimension of 1.4 at 19 meters of packer depth. The variation of flow dimension with different packer depths is interpreted by the variability of permissive fractures with depth. Zonal pumping tests led to the utilization of the Moench (1984) dual-porosity model because hydraulic characteristics in the test holes were most suitable to the fractured bedrocks. Water quality logs displayed a tendency to increase geothermal temperature, to increase pH and to decrease dissolved oxygen. In addition, there was an increasing tendency towards electrical conductance and a decreasing tendency towards dissolved oxygen at most fracture zones.

Spatial Characteristic in Food Sources for Benthic Invertebrates in an Estuary Tidal flat: Carbon and Nitrogen Stable Isotope Analyses (안정동위원소 비를 이용한 하구 갯벌에 있어서 저서 무척추 동물의 유기물 기원의 공간적 특성)

  • Shin, Woo-Seok;Lee, Yong-Doo
    • Journal of the Korean Society for Marine Environment & Energy
    • /
    • v.13 no.1
    • /
    • pp.53-59
    • /
    • 2010
  • The spatial variability in the food chain structure of an estuarine environment(Nanakita estuarine, Japan) was investigated using stable carbon and nitrogen isotope. Potential organic matter sources(TP:Terrstrial Plant, MPOM:Marine particulate organic matter, BMA:Benthic microalgae, EPOM:Estuarine particulate organic matter), sedimentary organic matter and benthic invertebrates(Nuttallia olivacea and Nereidae) were sampled at four locations with different tidal flat types(e.g. sanddy, sanddy-muddy and muddy). The main objective of the present study was to determine food sources of Nuttallia olivacea and Nereidae along with small-scale spatial variability within the community of benthic invertebrates. TP(${\delta}^{13}C=-26.6{\pm}0.76$ and ${\delta}^{15}N=2.7{\pm}0.31$) and EPOM(${\delta}^{13}C=-25.5{\pm}0.13$ and ${\delta}^{15}N=5.2{\pm}0.46$) were isotopically distinct from BMA(${\delta}^{13}C=-16.3$ and ${\delta}^{15}N=6.2$) and MPOM(${\delta}^{13}C=-19.6{\pm}0.08$ and ${\delta}^{15}N=8.9{\pm}1.70$). ${\delta}^{13}C$ values of sedimentary organic matter showed a distinct gradient in the range of -27.4 to -22.8‰ with a declining trend from the upstream to the downstream stations. The stable carbon and nitrogen isotope values of benthic invertebrates in the study site was -22.8 to -18.4‰ for ${\delta}^{16}C$ and 8.1 to 11.9‰ or ${\delta}^{15}N$, respectively. Mixing model(Isosource) calculations based on stable isotope measurements showed that benthic invertebrates of Nuttallia olivacea and Nereidae were found to be dominated by MPOM and BMA in stations. Whereas, TP and EPOM showed little influence to benthic invertebrates. The current result suggests that the different contribution for benthic invertebrates should be affected by both seasonal variation and physical factor among stations.

미취학 아동에 있어 신체발달, 손목 골밀도 및 영양섭취와의 상관성

  • 나현주;명금희;최미경;김애정
    • Proceedings of the KSCN Conference
    • /
    • 2003.11a
    • /
    • pp.1051-1052
    • /
    • 2003
  • 미취학 아동기는 생후 1년 동안의 급격한 성장 이후로부터 학령기가 되기 전까지 성장이 완만해지는 시기이다. 이 시기의 아동들은 혼자 먹는 행동을 익히게 되고 식품에 대한 기호가 형성되는 등 식생활에서도 뚜렷한 개인특성을 갖게되며 이 시기에 형성된 식습관은 성인까지 이어지게 된다. 이 시기에 영양부족에 따른 신체발달의 지연이나 영양과잉에 따른 비만과 같은 과다한 신체발달의 문제점이 지적되고 있어 올바른 식습관 형성은 신체발달과 밀접한 관련성이 있는 것으로 보여진다. 우리나라는 취약한 칼슘섭취 부족에 따라 골격건강에 대한 관심이 크게 증가하고 있는데, 모든 질환이 그러하듯이 골격질환도 치료보다는 예방적인 관리가 다양한 측면에서 효율적이다. 따라서 골격건강과 최적의 신체발달을 위한 식사인자는 매우 중요하며, 일생의 성장시기에 따라 서로 다른 인자들이 관여할 것으로 생각된다. 이에 본 연구에서는 성장이 이루어지면서 식품선택의 독립성이 확립되는 미취학 아동에 있어 신체와 골격 발달에 관련성이 있는 영양섭취 요인을 찾아봄으로써 골격과 신체 발달을 위한 올바른 식습관 형성에 필요한 기초자료를 제시하고자 하였다. 이에 46~84개월의 미취학 어린이 총 62명(남자 37명, 여자 25명)을 대상으로 어머니에 의한 설문조사를 실시하고 대상자의 신체계측(InBody, Biospace)과 손목의 골밀도(DEXA, Medilink)를 측정하였다. 설문지는 어린이와 부모의 일반사항, 어린이의 건강상태, 식습관 및 활동조사표와 24시간 회상법에 의한 식사조사표로 구성하였다. 식사섭취조사 결과는 CAN-Pro를 이용하여 영양소 섭취량을 분석하였으며, 모든 연구결과는 SAS program을 이용하여 통계 분석하였다. 연구결과를 요약하면 다음과 같다. 남녀 어린이의 평균 월령은 62.43$\pm$7.26 개월과 62.12$\pm$8.85개월이었다. 출생시 신장과 체중은 남자 어린이가 50.92$\pm$2.14 cm와 3.36$\pm$0.42kg, 여자 어린이는 각각 50.29$\pm$1.36cm와 3.32$\pm$0.39kg이었다. 현재 신장과 체중은 남자 111.65$\pm$5.44 cm와 19.60$\pm$3.52kg, 여자 109.04$\pm$5.04 cm와 18.67$\pm$2.81kg이었으며, 비만지수는 남녀 각각 -2.13$\pm$9.09%와 0.22$\pm$10.49%였다. 손목의 골밀도는 남녀 어린이 각각 0.25$\pm$0.04g/cm, 0.24$\pm$0.03g/$\textrm{cm}^2$이었다. 에너지 섭취량은 남녀 어린이 각각 영양권장량의 66.43$\pm$18.58%와 70.46$\pm$20.31% 수준이었으며, 남녀 어린이 모두 단백질(124.97$\pm$37.55%, 131.24$\pm$45.49%), 비타민B$_{6}$ (152.48$\pm$47.01%, 152.95$\pm$61.77%), 엽산(106.87$\pm$40.44%, 104.52$\pm$50.16%), 비타민 E (121.04$\pm$52.79%, 113.48$\pm$75.78%)를 제외한 영양소 섭취량이 권장량에 미달되는 섭취수준을 보였다. 특히 성장기에 중요한 칼슘도 남녀 어린이 각각 권장량의 62.21$\pm$39.46%와 70.07$\pm$34.52%로 낮게 섭취하고 있었다. 모든 영양소 섭취량은 남녀 어린이간에 유의한 차이가 없었다. 신체계측치와 영양섭취와의 관계에서 체중, 체수분량, 제지방량은 각각 동물성 철 섭취량과 유의한 부의 상관관계를 보였다(p<0.05, p<0.01, p<0.01). 골밀도와 영양섭취와의 관계에서 손목 골밀도는 식물성 칼슘 섭취량과 유의한 정의 상관관계를 보였고(p<0.05), 특히 위쪽 손목 골밀도는 동물성 단백질, 동물성 철 섭취량과 각각 유의한 부의 상관을 보였다(p<0.05, p<0.05). 이상의 연구결과를 종합할 때 성장이 진행되고 있는 미취학 아동에 있어 신체상태와 골밀도는 동물성 단백질, 식물성 칼슘, 동물성 철 섭취량과 상관성이 있는 것으로 나타남으로써 앞으로 이들 영양소의 섭취가 신체와 골격 성장에 어떠한 영향을 미치는가에 대한 보다 세부적인 연구가 이루어져야 할 것으로 생각된다.

  • PDF

Organizing an in-class hackathon to correct PDF-to-text conversion errors of Genomics & Informatics 1.0

  • Kim, Sunho;Kim, Royoung;Nam, Hee-Jo;Kim, Ryeo-Gyeong;Ko, Enjin;Kim, Han-Su;Shin, Jihye;Cho, Daeun;Jin, Yurhee;Bae, Soyeon;Jo, Ye Won;Jeong, San Ah;Kim, Yena;Ahn, Seoyeon;Jang, Bomi;Seong, Jiheyon;Lee, Yujin;Seo, Si Eun;Kim, Yujin;Kim, Ha-Jeong;Kim, Hyeji;Sung, Hye-Lynn;Lho, Hyoyoung;Koo, Jaywon;Chu, Jion;Lim, Juwon;Kim, Youngju;Lee, Kyungyeon;Lim, Yuri;Kim, Meongeun;Hwang, Seonjeong;Han, Shinhye;Bae, Sohyeun;Kim, Sua;Yoo, Suhyeon;Seo, Yeonjeong;Shin, Yerim;Kim, Yonsoo;Ko, You-Jung;Baek, Jihee;Hyun, Hyejin;Choi, Hyemin;Oh, Ji-Hye;Kim, Da-Young;Park, Hyun-Seok
    • Genomics & Informatics
    • /
    • v.18 no.3
    • /
    • pp.33.1-33.7
    • /
    • 2020
  • This paper describes a community effort to improve earlier versions of the full-text corpus of Genomics & Informatics by semi-automatically detecting and correcting PDF-to-text conversion errors and optical character recognition errors during the first hackathon of Genomics & Informatics Annotation Hackathon (GIAH) event. Extracting text from multi-column biomedical documents such as Genomics & Informatics is known to be notoriously difficult. The hackathon was piloted as part of a coding competition of the ELTEC College of Engineering at Ewha Womans University in order to enable researchers and students to create or annotate their own versions of the Genomics & Informatics corpus, to gain and create knowledge about corpus linguistics, and simultaneously to acquire tangible and transferable skills. The proposed projects during the hackathon harness an internal database containing different versions of the corpus and annotations.

Permanent Preservation and Use of Historical Archives : Preservation Issues Digitization of Historical Collection (역사기록물(Archives)의 항구적인 보존화 이용 : 보존전략과 디지털정보화)

  • Lee, Sang-min
    • The Korean Journal of Archival Studies
    • /
    • no.1
    • /
    • pp.23-76
    • /
    • 2000
  • In this paper, I examined what have been researched and determined about preservation strategy and selection of preservation media in the western archival community. Archivists have primarily been concerned with 'preservation' and 'use' of archival materials worth of being preserved permanently. In the new information era, preservation and use of archival materials were faced with new challenge. Life expectancy of paper records was shortened due to acidification and brittleness of the modem papers. Also emergence of information technology affects the traditional way of preservation and use of archival materials. User expectations are becoming so high technology-oriented and so complicated as to make archivists act like information managers using computer technology rather than traditional archival handicraft. Preservation strategy plays an important role in archival management as well as information management. For a cost-effective management of archives and archival institutions, preservation strategy is a must. The preservation strategy encompasses all aspects of archival preservation process and practices, from selection of archives, appraisal, inventorying, arrangement, description, conservation, microfilming or digitization, archival buildings, and access service. Those archival functions should be considered in their relations to each other to ensure proper preservation of archival materials. In the integrated preservation strategy, 'preservation' and 'use' should be combined and fulfilled without sacrificing the other. Preservation strategy planning is essential to determine the policies of archives to preserve their holdings safe and provide people with a maximum access in most effective ways. Preservation microfilming is to ensure permanent preservation of information held in important archival materials. To do this, a detailed standardization has been developed to guarantee the permanence of microfilm as well as its product quality. Silver gelatin film can last up to 500 years in the optimum storage environment and the most viable option for permanent preservation media. ISO and ANIS developed such standards for the quality of microfilms and microfilming technology. Preservation microfilming guidelines was also developed to ensure effective archival management and picture quality of microfilms. It is essential to assess the need of preservation microfilming. Limit in resources always put a restraint on preservation management. Appraisal (and selection) of what to be preserved was the most important part of preservation microfilming. In addition, microfilms with standard quality can be scanned to produce quality digital images for instant use through internet. As information technology develops, archivists began to utilize information technology to make preservation easier and more economical, and to promote use of archival materials through computer communication network. Digitization was introduced to provide easy and universal access to unique archives, and its large capacity of preserving archival data seems very promising. However, digitization, i.e., transferring images of records to electronic codes, still, needs to be standardized. Digitized data are electronic records, and st present electronic records are very unstable and not to be preserved permanently. Digital media including optical disks materials have not been proved as reliable media for permanent preservation. Due to their chemical coating and physical character using light, they are not stable and can be preserved at best 100 years in the optimum storage environment. Most CD-R can last only 20 years. Furthermore, obsolescence of hardware and software makes hard to reproduce digital images made from earlier versions. Even if when reformatting is possible, the cost of refreshing or upgrading of digital images is very expensive and the very process has to be done at least every five to ten years. No standard for this obsolescence of hardware and software has come into being yet. In short, digital permanence is not a fact, but remains to be uncertain possibility. Archivists must consider in their preservation planning both risk of introducing new technology and promising possibility of new technology at the same time. In planning digitization of historical materials, archivists should incorporate planning for maintaining digitized images and reformatting them in the coming generations of new applications. Without the comprehensive planning, future use of the expensive digital images will become unavailable. And that is a loss of information, and a final failure of both 'preservation' and 'use' of archival materials. As peter Adelstein said, it is wise to be conservative when considerations of conservations are involved.