• Title/Summary/Keyword: Systematic study

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Analysis of Benthic Macroinvertebrate Community Structure and Stability in Major Inflow Streams of Lake Andong and Lake Imha (안동·임하호 주요 유입지천의 저서성 대형무척추동물 군집구조 및 군집안정성 분석)

  • You, Hyuk;Lee, Mi Jin;Seo, Eul Won;Lee, Jong Eun
    • Korean Journal of Environmental Biology
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    • v.34 no.4
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    • pp.320-328
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    • 2016
  • This study was conducted to provide important basic information about effective management of the marine environment at major inflow streams in Lake Andong and Lake Imha. The investigation was conducted 8 times from May, 2015 (AD1, AD2, IH1, IH2) to September, 2016 (AD3, AD4, IH3, IH4), and 8 surveyed sites were selected at Lake Andong (4 sites) and Lake Imha (4 sites). The inquiry identified 114 species, $59,913.7inds.\;m^{-2}$ in Lake Andong and 112 species, $39,038.4inds.\;m^{-2}$ in Lake Imha. The results indicate that the number of species and individuals in Lake Andong is more than that in Lake Imha, because Lake Andong has a variety of riparian vegetation and a richness of organic materials. Community analysis at Lake Imha revealed a dominant index of 0.57 (${\pm}0.18$), a diversity index of 2.87 (${\pm}0.31$), an evenness index of 0.73 (${\pm}0.04$), and a richness index of 4.17 (${\pm}0.71$). The results of functional feeding group analysis showed that a high proportion of species and individuals are gathering collectors. The results of functional habitat group analysis showed that a high proportion of species and individuals are clingers. The result of a physico-chemical water assay and dissolved oxygen and electric conductivity tests revealed that these measures increased when the water temperature decreased. The result of Pearson's correlation analysis by biological factors and physico-chemical factors showed that species and electric conductivity are highly correlated with one another. Major inflow streams of Lake Andong and Lake Imha were exposed to various point pollution sources and non-point pollution sources. This implies a necessity for continuous monitoring of the aquatic ecosystems in order to effect systematic water quality management of Lake Andong and Lake Imha.

A Numerical Study of Hydraulic Fractures Propagation with Rock Bridges (Rock bridges를 고려한 수치 해석적 수압파쇄 균열거동 연구)

  • 최성웅
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • 2000.09a
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    • pp.201-210
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    • 2000
  • Rock bridge in rock masses can be considered as one of several types of opening-mode fractures, and also it has been known to have a great influence on the stability of structures in rock mats. In the beginning of researching a rock bridge it used to be studied only in characteristics of its behavior, as considering resistance of material itself. However the distribution pattern of rock bridges, which can affect the stability of rock structures, is currently researched with a fracture mechanical approach in numerical studies. For investigating the effect of rock bridges on the development pattern of hydraulic fractures, the author analyzed numerically the stress state transition in rock bridges and their phenomena with a different pattern of the rock bridge distributons. From the numerical studies, a two-crack configuration could be defined to be representative of the most critical conditions for rock bridges, only when cracks are systematic and same in their length and angle. Moreover, coalescence stresses and onset of propagation stresses could be known to increase with decreasing s/L ratio or increasing d/L ratio. The effect of pre-existing crack on hydraulic fracturing was studied also in numerical models. Different to the simple hydraulic fracturing modeling in which the fractures propagated exactly parallel to the maximum remote stress, the hydraulic fractures with pre-existing cracks dial not propagate parallel to the maximum remote stress direction. These are representative of the tendency to change the hydraulic fractures direction because of the existence of pre-existing crack. Therefore s/L, d/L ratios will be identical as a function effective on hydraulic fractures propagation, that is, the $K_{I}$ vague increase with decreasing s/L ratio or increasing d/L ratio and its magnification from onset to propagation increases with decreasing s/L ratio. The scanline is a commonly used method to estimate the fracture distribution on outcrops. The data obtained from the scanline method can be applied to the evaluation of stress field in rock mass.s.

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A Numerical Study of Hydraulic Fractures Propagation with Rock Bridges (Rock bridges를 고려한 수치 해석적 수압파쇄 균열거동 연구)

  • 최성웅
    • Tunnel and Underground Space
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    • v.10 no.3
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    • pp.447-456
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    • 2000
  • Rock bridge in rock masses can be considered as one of several types of opening-mode fractures, and also it has been known to have a great influence on the stability of structures in rock mass. In the beginning of researching a rock bridge it used to be studied only in characteristics of its behavior, as considering resistance of material itself. However the distribution pattern of rock bridges, which can affect the stability of rock structures, is currently researched with a fracture mechanical approach in numerical studies. For investigating the effect of rock bridges on the development pattern of hydraulic fractures, the author analyzed numerically the stress state transition in rock bridges and their phenomena with a different pattern of the rock bridge distributions. From the numerical studies, a two-crack configuration could be defined to be representative of the most critical conditions for rock bridges, only when cracks are systematic and same in their length and angle. Moreover, coalescence stresses and onset of propagation stresses could be known to increase with decreasing s/L ratio or increasing d/L ratio. The effect of pre-existing crack on hydraulic fracturing was studied also in numerical models. Different to the simple hydraulic fracturing modeling in which the fractures propagated exactly parallel to the maximum remote stress, the hydraulic fractures with pre-existing cracks did not propagate parallel to the maximum remote stress direction. These are representative of the tendency to change the hydraulic fractures direction because of the existence of pre-existing crack. Therefore s/L, d/L ratios will be identical as a function effective on hydraulic fractures propagation, that is, the K$_1$ value increase with decreasing s/L ratio or increasing d/L ratio and its magnification from onset to propagation increases with decreasing s/L ratio. The scanline is a commonly used method to estimate the fracture distribution on outcrops. The data obtained from the scanline method can be applied to the evaluation of stress field in rock mass.

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Isolation and Characterization of the IAA Producing Methylotrophic Bacteria from Phyllosphere of Rice Cultivars(Oryza sativa L.) (벼(Oryza sativa L.)의 잎 면으로부터의 IAA를 생성하는 Methylotrophic Bacteria의 분리 선별 및 특성 비교)

  • Lee, Kyu-Hoi;Munusamy , Madhaiyan;Kim, Chung-Woo;Lee, Hyoung-Seok;Selvaraj, Poonguzhali;Sa, TongMin
    • Korean Journal of Soil Science and Fertilizer
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    • v.37 no.4
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    • pp.235-244
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    • 2004
  • In this study, we compared the levels of methylotrophic bacterial community diversity in the leaf samples of 19 rice cultivars collected from three regions of Korea. Nineteen pink pigmented isolates showing characteristic growth on methanol were obtained. Physiological and biochemical characters of each isolate were examined according to methods described in Bergey's Manual of Systematic Bacteriology. When phylotypes were defined by performing numerical analysis of 37 characteristics, four distinct clusters were formed. The two reference strains, Methylobacterium extorquens AM1 and Methylobacterium fujisawaense KACC10744 were found to group under cluster IV and cluster III respectively. Cluster I diverged on the basis of nitrate reduction and four isolates showed tolerance upto 0.5 M NaCl concentrations. Two strains in cluster I and III were found to possess methane utilizing properties. Most of the isolates in all the four clusters utilized monosaccharides, disaccharide and polyols as carbon source. When the isolates were subjected for indole-3-acetic acid (IAA) analysis in the presence of L-tryptophan, only 8 isolates exhibited IAA production. In addition, the nitrogen source in the medium was found to influence the IAA production. Addition of $(NH_4)_2SO_4$ in the medium led to a 2 to 30 fold increase in the indole synthesis. However, $KNO_3$, $NH_4NO_3$ and $NH_4Cl$ substitution did not significantly stimulate the synthesis of IAA in the growth medium. Result of gnotobiotic root elongation assay significantly increased roots and shoots lengths, and number of lateral roots, which is mediated by IAA production in the culture medium. The rice seedlings primary roots from seeds treated with methylotrophic isolates were on average 27 to 56% longer than the roots from seeds treated with the uninoculated seeds. In addition, application of different high concentrations of authentic IAA ($400g\;mL^{-1}$) to roots of rice seedlings inhibited root growth. However, the IAA concentration from 10 to $200g\;mL^{-1}$, IAA promoted root growth of rice seedlings. These results suggest that bacterial IAA plays a major role in the development of the host plant root system.

The Effects of BizCool of Vocational High School on the Understanding of Enterprise Commencement and BizCool Outcomes (전문계 고교 창업교육(BizCool)이 창업인식 및 창업교육성과에 미치는 영향)

  • Cheon, Soo-Kyung;Jung, Hwa-Young
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.4 no.4
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    • pp.89-114
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    • 2009
  • BizCool is an entry-level business education program implemented with a purpose of enhancing the entrepreneurial disposition and capability of the youth through enterprise commencement education of vocational high school students and developing them into economic pillars of future to alleviate the labor shortage crisis of small and medium enterprises and revitalize enterprise commencement. In this study, the factors were deduced and a path analysis was conducted with the purpose of proposing a revitalization plan through an effectiveness analysis of enterprise commencement education for the youth. The result of the analysis revealed that BizCool has effects on the knowledge and understanding of enterprise commencement, and enterprise commencement knowledge also has effects on the understanding of enterprise commencement. In addition, it was found that the enterprise commencement knowledge and the understanding on enterprise commencement have effects on the intention of enterprise commence. In the result of verifying the hypothesis that the understanding of enterprise commencement according to the psychological characteristics of individuals will have a positive effect on the enterprise commencement intention, it was revealed that the risk resignation disposition and patience for ambiguity are having effects but accomplishment desire is not playing a moderating variable role. Through the above path analysis, a conclusion was obtained that the enterprise commencement education has effects on the outcome of enterprise commencement education through the understanding on enterprise commencement. Additionally, the nation needs to actively lead systematic enterprise commencement education within the policy of job creation upon realizing the need for enterprise commencement education of vocational high school, and a revitalization plan was proposed on the five kinds of a conversion of social perception on vocational high school, establishment of institutes specializing in BizCool and cultivation of BizCool specialists, development of various materials and expansion of BizCool program, field-centered lessons, revitalization of enterprise commencement club and personnel and resource support by companies.

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Rethinking Korean Women's Art from a Post-territorial Perspective: Focusing on Korean-Japanese third generation women artists' experience of diaspora and an interpretation of their work (탈영토적 시각에서 볼 수 있는 한국여성미술의 비평적 가능성 : 재일동포3세 여성화가의 '디아스포라'의 경험과 작품해석을 중심으로)

  • Suh, Heejung
    • The Journal of Art Theory & Practice
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    • no.14
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    • pp.125-158
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    • 2012
  • After liberation from Japanese colonial rule in 1945, there was the three-year period of United States Army Military Government in Korea. In 1948, Democratic People's Republic of Korea, and Republic of Korea were established in the north and south of the Korean Peninsula. The Republic of Korea is now a modern state set in the southern part of the Korean. We usually refer to Koreans as people who belong to the Republic of Korea. Can we say that is true exactly? Why make of this an obsolete question? The period from 1945 when Korea was emancipated from Japanese colonial rule to 1948 when the Republic of Korea was established has not been a focus of modern Korean history. This three years remains empty in Korean history and makes the concept of 'Korean' we usually consider ambiguous, and prompts careful attention to the silence of 'some Koreans' forced to live against their will in the blurred boundaries between nation and people. This dissertation regards 'Koreans' who came to live in the border of nations, especially 'Korean-Japanese third generation women artists'who are marginalized both Japan and Korea. It questions the category of 'Korean women's art' that has so far been considered, based on the concept of territory, and presents a new perspective for viewing 'Korean women's art'. Almost no study on Korean-Japanese women's art has been conducted, based on research on Korean diaspora, and no systematic historical records exist. Even data-collection is limited due to the political situation of South and North in confrontation. Representation of the Mother Country on the Artworks by First and Second-Generation Korean-Japanese(Zainich) Women Artists after Liberation since 1945 was published in 2011 is the only dissertation in which Korean-Japanese women artists, and early artistic activities. That research is based on press releases and interviews obtained through Japan. This thesis concentrates on the world of Korean-Japanese third generation women artists such as Kim Jung-sook, Kim Ae-soon, and Han Sung-nam, permanent residents in Japan who still have Korean nationality. The three Korean-Japanese third generation women artists whose art world is reviewed in this thesis would like to reveal their voices as minorities in Japan and Korea, resisting power and the universal concepts of nation, people and identity. Questioning the general notions of 'Korean women' and 'Korean women's art'considered within the Korean Peninsula, they explore their identity as Korean women outside the Korean territory from a post-territorial perspective and have a new understanding of the minority's diversity and difference through their eyes as marginal women living outside the mainstream of Korean and Japanese society. This is associated with recent post-colonial critical viewpoints reconsidering myths of universalism and transcendental aesthetic measures. In the 1980s and 1990s art museums and galleries in New York tried a critical shift in aesthetic discourse on contemporary art history, analyzed how power relationships among such elements as gender, sexuality, race, nationalism. Ghost of Ethnicity: Rethinking Art Discourses of the 1940s and 1980s by Lisa Bloom is an obvious presentation about the post-colonial discourse. Lisa Bloom rethinks the diversity of race, ethnicity, sexuality, and gender each artist and critic has, she began a new discussion on artists who were anti-establishment artists alienated by mainstream society. As migration rapidly increased through globalism lead by the United States the aspects of diaspora experience emerges as critical issues in interpreting contemporary culture. As a new concept of art with hybrid cultural backgrounds exists, each artist's cultural identity and specificity should be viewed and interpreted in a sociopolitical context. A criticism started considering the distinct characteristics of each individual's historical experience and cultural identity, and paying attention to experience of the third world artist, especially women artists, confronting the power of modernist discourses from a perspective of the white male subject. Considering recent international contemporary art, the Korean-Japanese third generation women artists who clarify their cultural identity as minority living in the border between Korea and Japan may present a new direction for contemporary Korean art. Their art world derives from their diaspora experience on colonial trauma historically. Their works made us to see that it is also associated with postcolonial critical perspective in the recent contemporary art stream. And it reminds us of rethinking the diversity of the minority living outside mainstream society. Thus, this should be considered as one of the features in the context of Korean women's art.

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SPECIES OF CULTIVATED PORPHYRA IN KOREA (한국산 양식김의 종류)

  • KANG Jae Won
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.3 no.2
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    • pp.77-92
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    • 1970
  • Ueda, in the course of his systematic work on the lavers, Porphyra, in Japan and Korea in 1932, mentioned that most of the cultivated Porphyra belong to Porphyra tenera Kjellman. Then he, dividing the species into two forms, f. typica and f. kjellmani, put Korean cultivated Porphyra under the latter. From the 1930s to the early 1940s, Fujikawa, Kaneko and others worked on Physiological experiments or cultivational experiments of Porphyra in the culture-bed, but there was no mention about the cultivated Porphyra species. However, many fishermen generally recognize that the characteristics of cultivated Porphyra vary depending on their habitat or the picking season, and it is considered that these differences are due to the varieties of the species which are well adaptable to various environments. Recently, I have become aware of the predominant occurrence of P. yezoensis Ueda in most culture-beds of Korea as in the Tokyo Bay or other places in Japan. At present, since artificial seeding for the cultivation of Porphyra with Conchocelis has been carried out and peculiar species can be cultured, a study of the species of cultivated Porphyra has become an important subject. I collected the specimens from a number of culture-beds which are located in the legions shown in fig. 1 from January, 1968 to May, 1970 and found that there are five species, P. tenera Kjellman, P. yezoensis Ueda, P. kuniedai Kurogi, P. seriata Kjellman and P. suborbiculata Kjellman. Among them, P. kuniedai was treated as a round-type, a form of P. tenera, by Kunieda (1939) and Tanaka (1952) and the occurrence of this form is generally recognized by most fishermen. At present, as mentioned above, the most dominant species of cultivated Porphyra is P. yezoensis but the cultivation of P. tenera is restricted to certain culture-beds or the early half of the cultivation period. P. kunieda appears as a mixed species throughout most of the culture-beds, particulary in the later half of the period, while when it was picked in January it appeared dominantly in a place such as Gum-Dang where the 'Bal', splitted bamboo piece mat, was settled during the last of September. This is the first seeding process. The latter two species, P. suborbiculata and P. seriata appear frequently but in small amounts in the later half of the period particulary in the western region of the southern coast. However, it can not be ascertained when P. yezoensis becomes predominant, because specimens have not been available up until recent years but the process can be described as follows: We commonly recognize the ecological characteristics of P. tenera as follows; First, the conchospores of the species develop earlier and the period of its discharge is shorter than those of P. yezoensis; second, the microscopical buds discharge neutral spores which develop into new buds directly and buds develop repeatedly through a short period. Consequently, according to such above ecological characteristics, the species can grow thick on the 'Bal' exclusively. However, buds may disappear when they are harmed by disease such a 'infection by certain parasites or by other unusual environmental conditions. Thus P. yezoensis are enabled to grow on the 'Bal' instead of the former species since they not only develop later than the former but also macroscopical fronds discharge the neutral spore throughout the period from October to May. Likewise, if any disease appears in the culture-bed ill the later half of the period, the former is more severely damaged than the latter because the former have less resistance to the disease than the latter. Thus fewer frond survive and fewer carpospores which are the origin of the next generation can be discharged. However the latter by their nature can continue growing until early summer. In the case of the culture-bed where the above phenomenon occurs repeatedly P. yezoensis gradually may become the dominant species among cultivated Porphyra. In support of the validity of this process we find that according to the description and the plate of Wada (1941), P. tenera, P. yezoensis and P. kuniedai grow together in the culture-bed at the mouth of the Nakdong River where P. yezoensis occurs predominantly and mixed with P. kuniedai.

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Relevance of Serum Vitamin D and Indices Related To Cardiovascular Disease Among Korean Adults (한국 성인의 혈청 비타민 D 수준과 심혈관 질환 관련 지표와의 관련성)

  • Kim, Han-Soo;Ryu, So-Yeon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.6
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    • pp.365-374
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    • 2018
  • This study investigated the relationship between Vitamin D levels and indices related to cardiovascular disease in Korean adults aged ${\geq}19years$. The data for analysis were obtained from the sixth Korea National Health Nutrition Examination Survey in 2013 and 2014. The results showed that the incidence of Vitamin D deficiency was 73.1% among Korean adults and that indices related to cardiovascular disease showed an increasing trend (55.6% of Korean adults). The relationship between Vitamin D levels and indices related to cardiovascular disease with controlled physical activity status was also studied. The odds ratios (ORs) for age were 1.72 for the 4-62 years age group (95% CI, 1.53-1.93) and 2.05 for the ${\geq}65years$ age group (95% CI, 1.71-2.45). For blood pressure, the OR for pre-hypertension was 1.30 (95% CI, 1.15-1.47) and that for hypertension was 1.31 (95% CI, 1.11-1.54). For body mass index (BMI), the OR was 1.36 (95% CI, 1.11-1.66) and that for waist circumference (WC) was 1.36 (95% CI, 1.11-1.66). For fasting blood sugar (FBS), the OR for impaired fasting glucose (IFG) was 1.37 (95% CI, 1.21-1.55) and that for diabetes mellitus (DM) was 1.31 (95% CI, 1.05-1.65). The OR for total cholesterol (TC) was 1.30 (95% CI, 1.11-1.52) and that for triglycerides (TG) was 1.20 (95% CI, 1.04-1.37) in Korean adults. There was a significant relationship between Vitamin D and indices related to cardiovascular disease in Korean adults with respect to age, blood pressure, FBS, BMI, TC and TG. Confirmation of a causal relationship between Vitamin D and indices related to cardiovascular disease may require further research consisting of more systematic cohort studies.

Developing and testing the reliability of a measurement tool for an urban area food environment in Korea - Focusing on food stores - (우리나라 도시지역의 식환경 측정을 위한 조사도구 개발 및 신뢰도 검정 - 식품상점을 중심으로 -)

  • Jang, Mi Jin;Shin, Sangah;Kim, Seong-Ah;Chung, Sangwon;Paik, Hee Young;Choe, Jeong-Sook;Hong, Eun Joo;Joung, Hyojee
    • Journal of Nutrition and Health
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    • v.47 no.5
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    • pp.351-363
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    • 2014
  • Purpose: The aim of this study was to develop a reliable measurement tool to assess the urban food environment, particularly focusing on food stores in Korea. Methods: The items for the measurement tool were selected through systematic literature reviews and adjusted to the Korean food environment. A total of 25 food stores in an urban area were recruited for the pilot test to evaluate the time required for completion of the survey, ease of response, willingness to participate, difficulties in conducting the survey, and appropriateness, and 34 food stores were recruited for assessment of the reliability of the tool using percent agreement and kappa value. Results: The measurement tool is composed of questions regarding food store characteristics, accessibility, and food availability. On average, 26 minutes was required to survey a single food store, and the subjects and interviewers answered that the process was not difficult for the survey. The percent agreement for the inter-rater and test-retest reliability ranged from 93.9~98.8% and 91.9~97.9, respectively. The kappa values ranged from 0.78 to 0.97, which was very high. Percent agreement and kappa value of food with healthy option were lower than those of the general food in the inter-rater reliability (p = 0.0027, p = 0.0095 respectively) as well as in the test-retest reliability (p = 0.0081, p = 0.0290, respectively), although they were still high enough (86.4~98.0% for percent agreement, 0.64~0.96 for kappa value). Conclusion: The newly developed measurement tool for assessment of food store environment appears to be feasible and reliable; therefore, it can be applied to research on the association between food environment and dietary behaviors as well as health outcomes.

Importance-Performance and Willingness to Purchase Analyses of Home Meal Replacement Using Eco-Friendly Food Ingredients in Undergraduates according to Gender (성별에 따른 대학생들의 친환경 식재료를 활용한 간편 가정식 구매의향 및 중요도-만족도 분석)

  • Jeong, Young-Gil;Lee, In-Seon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.44 no.12
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    • pp.1873-1880
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    • 2015
  • The purpose of this study was to survey intention to purchase home meal replacement (HMR) made with eco-friendly food ingredients as well as need for development while analyzing importance and performance of HMR made with eco-friendly ingredients for its commercialization. From September 2014 to March 2015, questionnaires were filled out by respondents. Of the 422 questionnaires that were returned, 412 were used with 10 discarded as incomplete. Regarding reasons behind purchasing HMR, the highest percentages of both males and females answered 'ready to eat'. Almost all respondents spent 'less than 10,000 won' each time they purchased HMR. Regarding place they bought HMR, a higher percentage of respondents answered 'convenience store' and 'discount retail chain store'. In terms of improvements needed for HMR, the highest percentage of males answered 'development of a variety of menus' while the highest percentage of females answered 'change in food ingredients' at 37.7%. For development of HMR made with eco-friendly ingredients, most respondents replied that there is a need for development. Regarding intention for purchasing HMR made with eco-friendly ingredients, 66.7% of males and 73.5% of females answered they have intention to buy. Important performance analysis showed a need to improve performance of 'safety of food ingredients', which was located close to the second quadrant. To improve performance for 'safety of food ingredients', safety must be ensured through use of eco-friendly ingredients, and a systematic process for managing hazardous materials that could arise during the manufacturing process has to be developed.