• Title/Summary/Keyword: 취약시간

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Evaluation of Chloride Diffusion Behavior and Analysis of Probabilistic Service Life in Long Term Aged GGBFS Concrete (장기 재령 GGBFS 콘크리트의 염화물 확산 거동 평가 및 확률론적 염해 내구수명 해석)

  • Yoon, Yong-Sik;Kim, Tae-Hoon;Kwon, Seung-Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.24 no.3
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    • pp.47-56
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    • 2020
  • In this study, three levels of W/B(Water to Binder) ratio (0.37, 0.42, 0.47) and substitution ratio of GGBFS (Ground Granulated Blast Furnace Slag) rate (0 %, 30 %, 50 %) were considered to perform RCPT (Rapid Chloride Diffusion Test) at the 1,095 aged day. Accelerated chloride diffusion coefficient and passed charge of each concrete mixture were assessed according to Tang's method and ASTM C 1202, and improving behaviors of durability performance with increasing aged days are analyzed based on the test results of previous aged days from the preceding study. As the age of concrete increases, the passed charge and diffusion coefficient have been significantly reduced, and especially the concrete specimens containing GGBFS showed a significantly more reduction than OPC(Ordinary Portland Cement) concrete specimen by latent hydraulic activity. In the case of OPC concrete's results of passed charge, at the 1,095 days, two of them were still in the "Moderate" class. So, if only OPC is used as the binder of concrete, the resistance performance for chloride attack is weak. In this study, the time-parameters (m) were derived based on the results of the accelerated chloride diffusion coefficient, and the deterministic and probabilistic analysis for service life were performed by assuming the design variable as a probability function. For probabilistic service life analysis, durability failure probabilities were calculated using Monte Carlo Simulation (MCS) to evaluate service life. The service life of probabilistic method were lower than that of deterministic method, since the target value of PDF (Probability of Durability Failure) was set very low at 10 %. If the target value of PDF suitable for the purpose of using structure can be set and proper variability can be considered for each design variable, it is believed that more economical durability design can be made.

미취학 아동에 있어 신체발달, 손목 골밀도 및 영양섭취와의 상관성

  • 나현주;명금희;최미경;김애정
    • Proceedings of the KSCN Conference
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    • 2003.11a
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    • pp.1051-1052
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    • 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.

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An Introduction of Korean Soil Information System (한국 토양정보시스템 소개)

  • Hong, S. Young;Zhang, Yong-Seon;Hyun, Byung-Keun;Sonn, Yeon-Kyu;Kim, Yi-Hyun;Jung, Sug-Jae;Park, Chan-Won;Song, Kwan-Cheol;Jang, Byoung-Choon;Choe, Eun-Young;Lee, Ye-Jin;Ha, Sang-Keun;Kim, Myung-Suk;Lee, Jong-Sik;Jung, Goo-Bok;Ko, Byong-Gu;Kim, Gun-Yeob
    • Korean Journal of Soil Science and Fertilizer
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    • v.42 no.1
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    • pp.21-28
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    • 2009
  • Detailed information on soil characteristics is of great importance for the use and conservation of soil resources that are essential for human welfare and ecosystem sustainability. This paper introduces soil inventory of Korea focusing on national soil database establishment, information systems, use, and future direction for natural resources management. Different scales of soil maps surveyed and soil test data collected by RDA (Rural Development Administration) were computerized to construct digital soil maps and database. Soil chemical properties and heavy metal concentrations in agricultural soils including vulnerable agricultural soils were investigated regularly at fixed sampling points. Internet-based information systems for soil and agro-environmental resources were developed based on 'National Soil Survey Projects' for managing soil resources and for providing soil information to the public, and 'Agroenvironmental Change Monitoring Project' to monitor spatial and temporal changes of agricultural environment will be opened soon. Soils data has a great potential of further application in estimation of soil carbon storage, water capacity, and soil loss. Digital mapping of soil and environment using state-of-the-art and emerging technologies with a pedometrics concept will lead to future direction.

Groundwater Recharge Evaluation on Yangok-ri Area of Hongseong Using a Distributed Hydrologic Model (VELAS) (분포형 수문모형(VELAS)을 이용한 홍성 양곡리 일대 지하수 함양량 평가)

  • Ha, Kyoochul;Park, Changhui;Kim, Sunghyun;Shin, Esther;Lee, Eunhee
    • Economic and Environmental Geology
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    • v.54 no.2
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    • pp.161-176
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    • 2021
  • In this study, one of the distributed hydrologic models, VELAS, was used to analyze the variation of hydrologic elements based on water balance analysis to evaluate the groundwater recharge in more detail than the annual time scale for the past and future. The study area is located in Yanggok-ri, Seobu-myeon, Hongseong-gun, Chungnam-do, which is very vulnerable to drought. To implement the VELAS model, spatial characteristic data such as digital elevation model (DEM), vegetation, and slope were established, and GIS data were constructed through spatial interpolation on the daily air temperature, precipitation, average wind speed, and relative humidity of the Korea Meteorological Stations. The results of the analysis showed that annual precipitation was 799.1-1750.8 mm, average 1210.7 mm, groundwater recharge of 28.8-492.9 mm, and average 196.9 mm over the past 18 years from 2001 to 2018 in the study area. Annual groundwater recharge rate compared to annual precipitation was from 3.6 to 28.2% with a very large variation and average 14.9%. By the climate change RCP 8.5 scenario, the annual precipitation from 2019 to 2100 was 572.8-1996.5 mm (average 1078.4 mm) and groundwater recharge of 26.7-432.5 mm (average precipitation 16.2%). The annual groundwater recharge rates in the future were projected from 2.8% to 45.1%, 18.2% on average. The components that make up the water balance were well correlated with precipitation, especially in the annual data rather than the daily data. However, the amount of evapotranspiration seems to be more affected by other climatic factors such as temperature. Groundwater recharge in more detailed time scale rather than annual scale is expected to provide basic data that can be used for groundwater development and management if precipitation are severely varied by time, such as droughts or floods.

Current State and the Future Tasks of Home Visit Nursing Care in South Korea (우리나라 가정방문간호의 현황과 향후 과제)

  • Park, Eunok
    • Journal of agricultural medicine and community health
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    • v.44 no.1
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    • pp.28-38
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    • 2019
  • Objectives: We searched and reviewed the literature including the laws or acts, statistics, guidelines, papers and conference proceedings related to home visit nursing care in South Korea. Method: We searched and reviewed the literature including the laws or acts, statistics, guidelines, papers and conference proceedings related to home visit nursing care in Korea. Results: There are three types of home care nursing in Korea. Public health center provides home visit nursing to vulnerable population by registered nurses for free, based on community health act in public health center. As of 2017, 1,261,208 people were enrolled in the visiting health program of public health center. Health behavior and disease management has been improved and showed having cost-benefit effect among the enrolled people in visiting health program. Visiting nursing care in long-term care services is provided by registered nurses or nurse aid, based on long-term care act. The cost is paid as the unit price according to service time. 1,095,764 older people used long-term care services in 2017, only 0.2% of total cost used for home visiting nursing. Even though the number of user of home visiting nursing, it was reported that users spent less medical cost and hospitalized shorter. Hospital-based home care nursing is provided to patients and their families under the prescription of a doctor by family nurse specialists who are employed by medical institute based on medical law. Four hundred sixty family nurse specialists worked for hospital-based home care nursing and hospital-based home care services accounted for 0.038% of total medical expenses in 2017. Conclusion: Even though home visit nursing care services are different in aspect of legal basis, personnel, running institutes, and cost basis, home visit nursing care showed cost-benefit effect and good health outcomes. In order to advance home visit nursing care, the integrated home visiting care, improvement of working condition, and revision of legal basis should be considered.

Comparison of Doses of Single Scan PBS and Layered Rescanning PBS Using Moving Phantom in Proton Therapy (양성자 치료에서 Moving Phantom을 이용한 Single Scan PBS와 Layered Rescanning PBS의 선량비교)

  • Kim, Kyeong Tae;Kim, Seon Yeong;Kim, Dae Woong;Kim, Jae Won;Park, Ji Yeon;Jeon, Sang Min
    • The Journal of Korean Society for Radiation Therapy
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    • v.31 no.1
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    • pp.43-49
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    • 2019
  • Purpose : We apply the Layered Rescanning PBS designed to complement the Pencil Beam Scanning(PBS), which is vulnerable to moving organs with the Moving Phantom, and compare the homogeneity with the single scan PBS. Methods and materials: Matrix X (IBA, Belgium) and Moving Phantom (standard imaging, USA) were used. A dose of 200 cGy was measured in the AP direction on a hypothetical tumor $10{\times}10{\times}5cm$. The plan type was planned as 4 kinds of sinlge scan PBS, rescan number 4, 8, 12 times. Were measured three times for each types. During the measurement, the respiratory cycle of the Moving Phantom was generally set to 4 seconds per cycle, and the movement radius in the S-I direction was set to 2 cm. In addition, beam on time was measured. Results : The mean values of $D_{max}$ in the PTV were $246.47{\pm}18.8cGy$, $223.43{\pm}8.92cGy$, and $222.47{\pm}7.7cGy$, $213.9{\pm}6.11cGy$ and the mean values of $D_{min}$ were $165.53{\pm}4.32cGy$, $173.13{\pm}11.94cGy$, $184.13{\pm}8.04cGy$, $182.67{\pm}4.38cGy$ and the mean values of $D_{mean}$ $192.77{\pm}6.98cGy$, $196.7{\pm}4.01cGy$, $198.17{\pm}4.96cGy$, $195.77{\pm}3.15cGy$ respectively. As the number of rescanning increased, the Homogeneity Index converged to 1. The beam on time was measured as 2:15, 3:15, 4:30, 5:37 on average. In the measurement process, in the low dose layer of the MU, the problem was found that it was not rescanned as many times as the set number of rescan. Conclusions : In the treatment of tumors with long-term movements, the application of layered rescanning PBS showed a more uniform dose distribution than single scan PBS. And as the number of rescan increase, the distribution of homogeneity is uniform. Compared with single scan plan and 12 rescan plan, HI value was improved by 0.32. Further studies are expected to be applicable to patients who can not be treated with respiratory synchronous radiation therapy.

An Examination on Dongbeomwas if Convex Roofing Tiles (수막새의 동범와(同范瓦)에 대한 검토 - 월성해자 출토 단판연화문 수막새를 중심으로 -)

  • Lee, Seonhui
    • Korean Journal of Heritage: History & Science
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    • v.39
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    • pp.59-93
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    • 2006
  • Wolseong in Gyeongju is a historic fortress site of Silla constructed under the reign of Pasanisageum that played politically and militarily important roles. The moat surrounding Wolseong had a function of protecting the fortress in wartimes but became a part of gardening in the unified Silla era. Lots of relics have been excavated from Wolseong moat since 1985. Among them a great number and kinds of convex roofing tiles are regarded as invaluable sources to show different aspects of Silla, from its earlier time through to the unified and on. Roofing tiles were widely used for national buildings such as royal palaces, temples and fortresses and even for other popular architecture and have been dug out a lot more than any other relics. Research on them, however, has been done poorly. Vigorous study is in progress with increasing number of roofing tiles coming from many recent excavations, though it has been limited to the studies on general genealogy of patterns and manufacture processes. Thus this essay seeks to find which are dongbeomwas, roofing tiles of a same mold, out of convex tiles with the pattern of a unilobed lotus flower dug out of Wolseong moat. It also attempts to identify dongbeomwas by examining detail characteristics of roofing tiles which have been confusingly termed as yusawa, similar roofing tiles, or donghyeongwa, roofing tiles of the same shape. The significance of identifying dongbeomwas could be emphasized by various facts resulting from researches on dongbeomwas; the ways to identify them correctly, their time sequence and their excavated sites. In conclusion, dongbeomwas were identified out of many kinds of convex tiles. If they were excavated from the same site, they share some common features. The sites where they were dug out also tell what changes were made with passage of time and what relations they had with neighboring Anapji. Since roofing tile molds haven't been found yet, the only way to identify dongbeomwas is to examine details of roofing tiles. Dongbeomwas excavated in Wolseong moat help to discuss the time of each district of it. Meanwhile it should be noted that the term 'dongbeomwa' be used only after exact examining.

Effects of Impact of Climate Change on Livestock Productivity - For bullocks, dairy, pigs, laying hens, and broilers - (기후변화가 축산 생산성에 미치는 영향 -거세우, 낙농, 양돈, 산란계, 육계를 대상으로-)

  • Lee, H.K.;Park, H.M.;Shin, Y.K.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.20 no.1
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    • pp.107-123
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    • 2018
  • The global impact of climate change on agriculture is now increasing. The purpose of this study was to investigate the effect of climate change on livestock productivity. The variables that have the greatest influence on climate change factors were examined through previous studies and expert surveys. We also used the actual productivity data of livestock farmers to investigate the relationship with climate change. In order to evaluate the climate for changes in livestock productivity, national representative data (such as bullocks, dairy, pigs, laying hens, and broilers) were surveyed in Korea. Also, to select and classify evaluation indexes, we selected climate change factor variables as prior studies and studied the weighting factor of climate variable factors. In this study, the researchers of industry, academia, and farmers in the livestock sector conducted questionnaires on the indicators of vulnerability to climate change using experts, and then weighed the selected indicators using the hierarchical analysis process (AHP). In order to verify the validity of the evaluation index, was examined using domestic climate data (temperature, precipitation, humidity, etc.). Correlation and regression analysis were performed. The empirical relationship between climate change and livestock productivity was examined through this study. As a result, we used data with high reliability of statistical analysis and found that there are significant variables.

An Analytical Study on the Seismic Behavior and Safety of Vertical Hydrogen Storage Vessels Under the Earthquakes (지진 시 수직형 수소 저장용기의 거동 특성 분석 및 안전성에 관한 해석적 연구)

  • Sang-Moon Lee;Young-Jun Bae;Woo-Young Jung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.6
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    • pp.152-161
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    • 2023
  • In general, large-capacity hydrogen storage vessels, typically in the form of vertical cylindrical vessels, are constructed using steel materials. These vessels are anchored to foundation slabs that are specially designed to suit the environmental conditions. This anchoring method involves pre-installed anchors on top of the concrete foundation slab. However, it's important to note that such a design can result in concentrated stresses at the anchoring points when external forces, such as seismic events, are at play. This may lead to potential structural damage due to anchor and concrete damage. For this reason, in this study, it selected an vertical hydrogen storage vessel based on site observations and created a 3D finite element model. Artificial seismic motions made following the procedures specified in ICC-ES AC 156, as well as domestic recorded earthquakes with a magnitude greater than 5.0, were applied to analyze the structural behavior and performance of the target structures. Conducting experiments on a structure built to actual scale would be ideal, but due to practical constraints, it proved challenging to execute. Therefore, it opted for an analytical approach to assess the safety of the target structure. Regarding the structural response characteristics, the acceleration induced by seismic motion was observed to amplify by approximately ten times compared to the input seismic motions. Additionally, there was a tendency for a decrease in amplification as the response acceleration was transmitted to the point where the centre of gravity is located. For the vulnerable components, specifically the sub-system (support columns and anchorages), the stress levels were found to satisfy the allowable stress criteria. However, the concrete's tensile strength exhibited only about a 5% margin of safety compared to the allowable stress. This indicates the need for mitigation strategies in addressing these concerns. Based on the research findings presented in this paper, it is anticipated that predictable load information for the design of storage vessels required for future shaking table tests will be provided.

Comparative analysis of food intake according to the family type of elderly women in Seoul area (서울 일부지역 여자 노인들의 가구유형에 따른 영양소 섭취실태 및 식사의 질 평가)

  • Lee, Yeon Joo;Kwon, Min Kyung;Baek, Hee Joon;Lee, Sang Sun
    • Journal of Nutrition and Health
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    • v.48 no.3
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    • pp.277-288
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    • 2015
  • Purpose: As the rate of senior citizens living alone increases in the current aging society, there is much concern regarding the health and nutritional intake of solitary senior citizens. Therefore, this study compared the nutritional intake of senior citizens according to their family type. Methods: In July and August of 2011, two senior citizen welfare centers in Seoul were visited to survey 267 elderly women. Excluding 54 subjects for which the data were incomplete, information from 213 subjects was analyzed. The subjects were divided into three family types, living alone (LA, n = 74), living with spouse (LS, n = 78), and living with children (LC, n = 61). Results: The mean age of the LA group was the highest, while the mean age of the LS group was the lowest (p < 0.001), and WHR of the LC group was the highest (p = 0.049). Income was the highest in the LS group (p < 0.001). Frequency of eating out was the lowest in the LA group (p = 0.031). By Duncan's multiple analysis, the amounts of energy intake, vegetable protein, fat, calcium, phosphorus, potassium, selenium, Vit D, Vit E, $Vit\;B_2$, niacin, $Vit\;B_6$, $Vit\;B_{12}$, and cholesterol were significantly higher in the LS group compared with the LA or LC group (p < 0.05). The intakes of calcium, Vit D, $Vit\;B_{12}$, and cholesterol were still significantly different among the three groups, even after adjustment for age and monthly income. The LA group ate less fruit and fish than the LS or LC group (p < 0.05). The LA group showed the lowest dietary diversity and the LS group showed the highest diversity (p = 0.014), however, the significance of dietary diversity score among the three groups disappeared after adjustment for age and monthly income. Conclusion: Elderly women living with spouse were receiving better nutrition than elderly women living alone or living with children. Therefore, solitary elderly women who do not live with their spouse or children should be offered greater opportunities to receive a balanced meal at a congregational kitchen or welfare center. To ensure their healthy diet, it is essential to provide continuous nutrition education with these groups in mind.