• Title/Summary/Keyword: Two-way Effect

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Understanding User Motivations and Behavioral Process in Creating Video UGC: Focus on Theory of Implementation Intentions (Video UGC 제작 동기와 행위 과정에 관한 이해: 구현의도이론 (Theory of Implementation Intentions)의 적용을 중심으로)

  • Kim, Hyung-Jin;Song, Se-Min;Lee, Ho-Geun
    • Asia pacific journal of information systems
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    • v.19 no.4
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    • pp.125-148
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    • 2009
  • UGC(User Generated Contents) is emerging as the center of e-business in the web 2.0 era. The trend reflects changing roles of users in production and consumption of contents on websites and helps us to understand new strategies of websites such as web portals and social network websites. Nowadays, we consume contents created by other non-professional users for both utilitarian (e.g., knowledge) and hedonic values (e.g., fun). Also, contents produced by ourselves (e.g., photo, video) are posted on websites so that our friends, family, and even the public can consume those contents. This means that non-professionals, who used to be passive audience in the past, are now creating contents and share their UGCs with others in the Web. Accessible media, tools, and applications have also reduced difficulty and complexity in the process of creating contents. Realizing that users create plenty of materials which are very interesting to other people, media companies (i.e., web portals and social networking websites) are adjusting their strategies and business models accordingly. Increased demand of UGC may lead to website visits which are the source of benefits from advertising. Therefore, they put more efforts into making their websites open platforms where UGCs can be created and shared among users without technical and methodological difficulties. Many websites have increasingly adopted new technologies such as RSS and openAPI. Some have even changed the structure of web pages so that UGC can be seen several times to more visitors. This mainstream of UGCs on websites indicates that acquiring more UGCs and supporting participating users have become important things to media companies. Although those companies need to understand why general users have shown increasing interest in creating and posting contents and what is important to them in the process of productions, few research results exist in this area to address these issues. Also, behavioral process in creating video UGCs has not been explored enough for the public to fully understand it. With a solid theoretical background (i.e., theory of implementation intentions), parts of our proposed research model mirror the process of user behaviors in creating video contents, which consist of intention to upload, intention to edit, edit, and upload. In addition, in order to explain how those behavioral intentions are developed, we investigated influences of antecedents from three motivational perspectives (i.e., intrinsic, editing software-oriented, and website's network effect-oriented). First, from the intrinsic motivation perspective, we studied the roles of self-expression, enjoyment, and social attention in forming intention to edit with preferred editing software or in forming intention to upload video contents to preferred websites. Second, we explored the roles of editing software for non-professionals to edit video contents, in terms of how it makes production process easier and how it is useful in the process. Finally, from the website characteristic-oriented perspective, we investigated the role of a website's network externality as an antecedent of users' intention to upload to preferred websites. The rationale is that posting UGCs on websites are basically social-oriented behaviors; thus, users prefer a website with the high level of network externality for contents uploading. This study adopted a longitudinal research design; we emailed recipients twice with different questionnaires. Guided by invitation email including a link to web survey page, respondents answered most of questions except edit and upload at the first survey. They were asked to provide information about UGC editing software they mainly used and preferred website to upload edited contents, and then asked to answer related questions. For example, before answering questions regarding network externality, they individually had to declare the name of the website to which they would be willing to upload. At the end of the first survey, we asked if they agreed to participate in the corresponding survey in a month. During twenty days, 333 complete responses were gathered in the first survey. One month later, we emailed those recipients to ask for participation in the second survey. 185 of the 333 recipients (about 56 percentages) answered in the second survey. Personalized questionnaires were provided for them to remind the names of editing software and website that they reported in the first survey. They answered the degree of editing with the software and the degree of uploading video contents to the website for the past one month. To all recipients of the two surveys, exchange tickets for books (about 5,000~10,000 Korean Won) were provided according to the frequency of participations. PLS analysis shows that user behaviors in creating video contents are well explained by the theory of implementation intentions. In fact, intention to upload significantly influences intention to edit in the process of accomplishing the goal behavior, upload. These relationships show the behavioral process that has been unclear in users' creating video contents for uploading and also highlight important roles of editing in the process. Regarding the intrinsic motivations, the results illustrated that users are likely to edit their own video contents in order to express their own intrinsic traits such as thoughts and feelings. Also, their intention to upload contents in preferred website is formed because they want to attract much attention from others through contents reflecting themselves. This result well corresponds to the roles of the website characteristic, namely, network externality. Based on the PLS results, the network effect of a website has significant influence on users' intention to upload to the preferred website. This indicates that users with social attention motivations are likely to upload their video UGCs to a website whose network size is big enough to realize their motivations easily. Finally, regarding editing software characteristic-oriented motivations, making exclusively-provided editing software more user-friendly (i.e., easy of use, usefulness) plays an important role in leading to users' intention to edit. Our research contributes to both academic scholars and professionals. For researchers, our results show that the theory of implementation intentions is well applied to the video UGC context and very useful to explain the relationship between implementation intentions and goal behaviors. With the theory, this study theoretically and empirically confirmed that editing is a different and important behavior from uploading behavior, and we tested the behavioral process of ordinary users in creating video UGCs, focusing on significant motivational factors in each step. In addition, parts of our research model are also rooted in the solid theoretical background such as the technology acceptance model and the theory of network externality to explain the effects of UGC-related motivations. For practitioners, our results suggest that media companies need to restructure their websites so that users' needs for social interaction through UGC (e.g., self-expression, social attention) are well met. Also, we emphasize strategic importance of the network size of websites in leading non-professionals to upload video contents to the websites. Those websites need to find a way to utilize the network effects for acquiring more UGCs. Finally, we suggest that some ways to improve editing software be considered as a way to increase edit behavior which is a very important process leading to UGC uploading.

The Effect of Low-Intensity Pulsed Ultrasound on Fracture Healing in the Rabbit Model (토끼모델에서 저강도 맥동초음파가 골절치유에 미치는 영향)

  • Kim, Jong-Man;Yi, Chung-Hwi;Cho, Sang-Hyun;Park, Jung-Mi;Kwon, Hyuk-Cheol;Hwang, Tae-Sun
    • Physical Therapy Korea
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    • v.9 no.1
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    • pp.81-96
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    • 2002
  • The purpose of this research was to determine the effects on the healing of fibular fractures in rabbits of low-intensity pulsed ultrasound (50 $mW/cm^2$ and 500 $mW/cm^2$) applied for periods of 4, 14 and 24 days following fibular osteotomy. Thirty-six male Japanese white rabbits were randomly divided into three groups of twelve for three treatment protocols: (1) ultrasound treatment at intensities of 50 $mW/cm^2$ and 500 $mW/cm^2$ until the 4th day following fibular osteotomy, (2) ultrasound treatment at intensities of 50 $mW/cm^2$ and 500 $mW/cm^2$ until the 14th day following fibular osteotomy, and (3) ultrasound treatment at intensities of 50 $mW/cm^2$ and 500 $mW/cm^2$ until the 24th day following fibular osteotomy. The low-intensity pulsed ultrasound was applied to only one fibula of each rabbit (these served as the experimental group). The other fibula of each rabbit served as the control group. The selection of which fibula was to be treated was made randomly. The animals were sacrificed on the 4th, 14th and 24th day after the start of ultrasound treatments. Percent of trabecular bone area and fibular radiography were carried out to compare the degree of fibular bone healing. A microscope was also used to determine any histologic changes. For statistical differences in radiological changes due to length of treatment period (4, 14 and 24 days respectively), the Wilcoxon signed-ranks test was used to compare the experimental and control groups. For statistical differences in fracture healing due to differences in ultrasound intensity, radiological studies were compared using the Mann-Whitney Test. And, to compute percentage differences in areas of trabecular bone, Two-way analysis of variance (ultrasound intensity x each group) was used. Experiment results were as follows: 1. In animals sacrificed on the 4th day, no difference was found in the radiological studies of the fibulae in the experimental and control groups (p>.05). However, experimental groups showed more rapid bone repair than control group. 2. Both radiographic and percent of trabecular bone area studies showed significant differences in rabbits sacrificed after 14 days. Fracture healing was significantly increased in the experimental group (p<.05) 3. In the animals sacrificed on the 24th day, histologic study showed rapid bone repair but fibular radiologic studies did not show statistical differences between the two groups (p>.05). 4. On the 14th day, bone union on radiograph was significantly more rapid in the treatment group with pulsed ultrasound of 50 $mW/cm^2$ than the group with 500 $mW/cm^2$ (p<.05). Histologic studies showed that both the 14 and 24 days groups had more rapid bone repair in animals treated with 50 $mW/cm^2$ ultrasound intensity than those treated with 500 $mW/cm^2$ intensity. In conclusion, it has been shown that the low-intensity pulsed ultrasound has a positive effect on bone fracture healing in the early stage and the range of pulse ultrasound from 50 $mW/cm^2$ to 500 $mW/cm^2$ is effective for fracture healing. Further study is needed to investigate the influence of pulsed ultrasound on delayed union and non-union in bone fractures and also for the clinical use of low-intensity pulsed ultrasound for bone healing in humans.

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Effects of mixing and reciprocal inoculation with compatible and incompatible races of Pyricularia oryzae on the enlargement of disease lesions of rice blast (친화성 및 비친화성균계의 혼합 및 전후접종이 벼 도열병의 병반확대에 미치는 영향)

  • Park Seur Kee;Kim Ki Chung
    • Korean journal of applied entomology
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    • v.22 no.4 s.57
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    • pp.300-306
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    • 1983
  • Effect on blast lesion development was investigated in rice cultivar Milyang 23 and Jinheung using two races of Pyricularia oryzae compatible or incompatible to each of two rice cultivars. Discase lesions were measured in rice when inoculated with inoculum mixed with compatible and incompatible races, inoculated with a compatible race following with an incompatible race and vice versa. Lesions were smaller when rice was incoulated with an incompatible race and then inoculated with a compatible race than those inoculated in the reverse way both at the inoculated site and at 3cm-upper part from inoculated spot. The results suggested that induced resistance might play a role in suppression of lesion development although such an effect appeared to be influenced by heavy application of nitrogen fertilizer.

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The effect of university students' participation in the entrepreneurship planning course on the enhancement of core competencies of entrepreneurship: Focusing on the case of S women's university (대학생의 창업계획 교육과정 참여가 창업가정신 핵심역량 증진에 미치는 효과: S여대 사례를 중심으로)

  • Kyun, Suna;Seo, Heejeon
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.17 no.5
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    • pp.81-94
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    • 2022
  • This study analyzed the effect of the entrepreneurship planning course provided by an women's university in Seoul on the enhancement of the core competencies of entrepreneurship of university students. To this end, pre- and post-test of core entrepreneurship competency were conducted on 63 female university students (32 in experimental group, 31 in control group) and then the results were analyzed. The course in which the experimental group participated was a team-based project learning course and it required a team of three people to draw an entrepreneurship plan containing social problem solving as the final result. The course was operated for a total of 8 weeks. To measure the level of entrepreneurship core competency in the pre- and post- test, the survey tool that was developed by the Ministry of Education and Korea Entrepreneurship Foundation (2020) was used. This tool composed by 'value creation', 'challenge', 'self-directed', and 'group creativity' competencies. As analyses methods, i) covariance analysis was performed using the pretest as a covariate, and then a two-way ANOVA was performed with treatment (experimental group, control group) and time point (pre test, post test) as two independent variables. Results show while there was no significant difference between the experimental group and the control group in the value creation competency, it significantly contributed to the enhancement of challenge, self-directed, and collective creativity competencies. Based on these results, implications and limitations were discussed, followed by future research direction.

The Usefulness of Product Display of Online Store by the Product Type of Usage Situation - Focusing on the moderate effect of the product portability - (사용상황별 제품유형에 따른 온라인 점포 제품디스플레이의 유용성 - 제품 휴대성의 조절효과를 중심으로 -)

  • Lee, Dong-Il;Choi, Seung-Hoon
    • Journal of Distribution Research
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    • v.16 no.2
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    • pp.1-24
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    • 2011
  • 1. Introduction: Contrast to the offline purchasing environment, online store cannot offer the sense of touch or direct visual information of its product to the consumers. So the builder of the online shopping mall should provide more concrete and detailed product information(Kim 2008), and Alba (1997) also predicted that the quality of the offered information is determined by the post-purchase consumer satisfaction. In practice, many fashion and apparel online shopping malls offer the picture information with the product on the real person model to enhance the usefulness of product information. On the other virtual product experience has been suggested to the ways of overcoming the online consumers' limited perceptual capability (Jiang & Benbasat 2005). However, the adoption and the facilitation of the virtual reality tools requires high investment and technical specialty compared to the text/picture product information offerings (Shaffer 2006). This could make the entry barrier to the online shopping to the small retailers and sometimes it could be demanding high level of consumers' perceptual efforts. So the expensive technological solution could affects negatively to the consumer decision making processes. Nevertheless, most of the previous research on the online product information provision suggests the VR be the more effective tools. 2. Research Model and Hypothesis: Presented in

    , research model suggests VR effect could be moderated by the product types by the usage situations. Product types could be defined as the portable product and installed product, and the information offering type as still picture of the product, picture of the product with the real-person model and VR. 3. Methods and Results: 3.1. Experimental design and measured variables We designed the 2(product types) X 3(product information types) experimental setting and measured dependent variables such as information usefulness, attitude toward the shopping mall, overall product quality, purchase intention and the revisiting intention. In the case of information usefulness and attitude toward the shopping mall were measured by multi-item scale. As a result of reliability test, Cronbach's Alpha value of each variable shows more than 0.6. Thus, we ensured that the internal consistency of items. 3.2. Manipulation check The main concern of this study is to verify the moderate effect by the product type of usage situation. indicates that our experimental manipulation of the moderate effect of the product type was successful. 3.3. Results As
    indicates, there was a significant main effect on the only one dependent variable(attitude toward the shopping mall) by the information types. As predicted, VR has highest mean value compared to other information types. Thus, H1 was partially supported. However, main effect by the product types was not found. To evaluate H2 and H3, a two-way ANOVA was conducted. As
    indicates, there exist the interaction effects on the three dependent variables(information usefulness, overall product quality and purchase intention) by the information types and the product types. As predicted, picture of the product with the real-person model has highest mean among the information types in the case of portable product. On the other hand, VR has highest mean among the information types in the case of installed product. Thus, H2 and H3 was supported. 4. Implications: The present study found the moderate effect by the product type of usage situation. Based on the findings the following managerial implications are asserted. First, it was found that information types are affect only the attitude toward the shopping mall. The meaning of this finding is that VR effects are not enough to understand the product itself. Therefore, we must consider when and how to use this VR tools. Second, it was found that there exist the interaction effects on the information usefulness, overall product quality and purchase intention. This finding suggests that consideration of usage situation helps consumer's understanding of product and promotes their purchase intention. In conclusion, not only product attributes but also product usage situations must be fully considered by the online retailers when they want to meet the needs of consumers.

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  • A Study on Market Expansion Strategy via Two-Stage Customer Pre-segmentation Based on Customer Innovativeness and Value Orientation (고객혁신성과 가치지향성 기반의 2단계 사전 고객세분화를 통한 시장 확산 전략)

    • Heo, Tae-Young;Yoo, Young-Sang;Kim, Young-Myoung
      • Journal of Korea Technology Innovation Society
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      • v.10 no.1
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      • pp.73-97
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      • 2007
    • R&D into future technologies should be conducted in conjunction with technological innovation strategies that are linked to corporate survival within a framework of information and knowledge-based competitiveness. As such, future technology strategies should be ensured through open R&D organizations. The development of future technologies should not be conducted simply on the basis of future forecasts, but should take into account customer needs in advance and reflect them in the development of the future technologies or services. This research aims to select as segmentation variables the customers' attitude towards accepting future telecommunication technologies and their value orientation in their everyday life, as these factors wilt have the greatest effect on the demand for future telecommunication services and thus segment the future telecom service market. Likewise, such research seeks to segment the market from the stage of technology R&D activities and employ the results to formulate technology development strategies. Based on the customer attitude towards accepting new technologies, two groups were induced, and a hierarchical customer segmentation model was provided to conduct secondary segmentation of the two groups on the basis of their respective customer value orientation. A survey was conducted in June 2006 on 800 consumers aged 15 to 69, residing in Seoul and five other major South Korean cities, through one-on-one interviews. The samples were divided into two sub-groups according to their level of acceptance of new technology; a sub-group demonstrating a high level of technology acceptance (39.4%) and another sub-group with a comparatively lower level of technology acceptance (60.6%). These two sub-groups were further divided each into 5 smaller sub-groups (10 total smaller sub-groups) through two rounds of segmentation. The ten sub-groups were then analyzed in their detailed characteristics, including general demographic characteristics, usage patterns in existing telecom services such as mobile service, broadband internet and wireless internet and the status of ownership of a computing or information device and the desire or intention to purchase one. Through these steps, we were able to statistically prove that each of these 10 sub-groups responded to telecom services as independent markets. We found that each segmented group responds as an independent individual market. Through correspondence analysis, the target segmentation groups were positioned in such a way as to facilitate the entry of future telecommunication services into the market, as well as their diffusion and transferability.

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    The Study of Land Surface Change Detection Using Long-Term SPOT/VEGETATION (장기간 SPOT/VEGETATION 정규화 식생지수를 이용한 지면 변화 탐지 개선에 관한 연구)

    • Yeom, Jong-Min;Han, Kyung-Soo;Kim, In-Hwan
      • Journal of the Korean Association of Geographic Information Studies
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      • v.13 no.4
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      • pp.111-124
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      • 2010
    • To monitor the environment of land surface change is considered as an important research field since those parameters are related with land use, climate change, meteorological study, agriculture modulation, surface energy balance, and surface environment system. For the change detection, many different methods have been presented for distributing more detailed information with various tools from ground based measurement to satellite multi-spectral sensor. Recently, using high resolution satellite data is considered the most efficient way to monitor extensive land environmental system especially for higher spatial and temporal resolution. In this study, we use two different spatial resolution satellites; the one is SPOT/VEGETATION with 1 km spatial resolution to detect coarse resolution of the area change and determine objective threshold. The other is Landsat satellite having high resolution to figure out detailed land environmental change. According to their spatial resolution, they show different observation characteristics such as repeat cycle, and the global coverage. By correlating two kinds of satellites, we can detect land surface change from mid resolution to high resolution. The K-mean clustering algorithm is applied to detect changed area with two different temporal images. When using solar spectral band, there are complicate surface reflectance scattering characteristics which make surface change detection difficult. That effect would be leading serious problems when interpreting surface characteristics. For example, in spite of constant their own surface reflectance value, it could be changed according to solar, and sensor relative observation location. To reduce those affects, in this study, long-term Normalized Difference Vegetation Index (NDVI) with solar spectral channels performed for atmospheric and bi-directional correction from SPOT/VEGETATION data are utilized to offer objective threshold value for detecting land surface change, since that NDVI has less sensitivity for solar geometry than solar channel. The surface change detection based on long-term NDVI shows improved results than when only using Landsat.

    Cultivation Condition of Transformant Alcaligenes eutrophus Harboring Cloned phbC Gene for Production of P(3-hydroxybutyrate-3-hydroxyvalernte) Containing High Molar Fraction of 3-Hydroxyvalerate. (P(3-hydroxybutyrate-3-hydroxyvalerate)의 생산을 위한 재조합 phbC 유전자를 형질전환시킨 Alcaligenes eutrophus의 배양조건 검토)

    • 권순일;정영미;이용현
      • Microbiology and Biotechnology Letters
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      • v.26 no.6
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      • pp.537-544
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      • 1998
    • The cultivation conditions of transformant Alcaligenes eutrophus AER5 harboring cloned phbC gene for mass production of poly (3-hydroxybutyrate-3-hydroxyvalerate)[P(3HB-3HV)] containing high molar fraction of 3-hydroxyvalerate (3-HV) were investigated. In two-stage batch cultivation, transformant accumulated P(3HB-3HV) containing 52.2 mol% of 3HV compared to 30 mol% of parent strain A. eutrophus H16. The increased 3-HV molar fraction was due to the amplified activity of PHB synthase participating in condensation of 3-HB and 3-HV. To increase efficiency of P(3HB-3HV) accumulation, fructose was added along with precursor compound valerate, and total cell mass and P(3HB-3HV) concentrations remarkably increased, but not 3-HV molar fraction. The effect of magnesium ion showed that P(3HB-3HV) concentration and 3-HV molar fraction were significantly increased upto 6.1 g/L and 71.3 mol% at 0.01 g/L of MgSO$_4$, respectively. The efficiency of several pH adjuster, NaOH, NaOH and (NH$_4$)$_2$SO$_4$, and NH$_4$OH, on total cell mass, p(3HB-3HV) concentration, and 3-HV molar fraction was also compared. To overcome the disadvantage of two-stage cultivation, one-stage intermittent fed-batch cultivation was attempted, such a way 10.0 g/L of fructose was supplied for cell growth at initial 36 hr and then 10.0 g/L of valerate and 5.0 g/L of fructose were applied to induce the accumulation of P(3HB-3HV), consequently, 10.4 g/L of P(3HB-3HV) with 38 mol% of 3-HV fraction could be obtained after 72 hr. These results can be used for elucidating cultivation strategy for mass production of P(3HB-3HV) containing high 3-HV molar fraction using transformant A. eutrophus AER5 harboring cloned phbC gene.

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    Development of Algorithm in Analysis of Single Trait Animal Model for Genetic Evaluation of Hanwoo (단형질 개체모형을 이용한 한우 육종가 추정프로그램 개발)

    • Koo, Yangmo;Kim, Jungil;Song, Chieun;Lee, Kihwan;Shin, Jaeyoung;Jang, Hyungi;Choi, Taejeong;Kim, Sidong;Park, Byoungho;Cho, Kwanghyun;Lee, Seungsoo;Choy, Yunho;Kim, Byeongwoo;Lee, Junggyu;Song, Hoon
      • Journal of Animal Science and Technology
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      • v.55 no.5
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      • pp.359-365
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      • 2013
    • Estimate breeding value can be used as single trait animal model was developed directly using the Fortran language program. The program is based on data computed by using the indirect method repeatedly. The program develops a common algorithm and imprves efficiency. Algorithm efficiency was compared between the two programs. Estimated using the solution is easy to farm and brand the service, pedigree data base was associated with the development of an improved system. The existing program that uses the single trait animal model and the comparative analysis of efficiency is weak because the estimation of the solution and the conventional algorithm programmed through regular formulation involve many repetition; therefore, the newly developed algorithm was conducted to improve speed by reducing the repetition. Single trait animal model was used to analyze Gauss-Seidel iteration method, and the aforesaid two algorithms were compared thorough the mixed model equation which is used the most commonly in estimating the current breeding value by applying the procedures such as the preparation of information necessary for modelling, removal of duplicative data, verifying the parent information of based population in the pedigree data, and assigning sequential numbers, etc. The existing conventional algorithm is the method for reading and recording the data by utilizing the successive repetitive sentences, while new algorithm is the method for directly generating the left hand side for estimation based on effect. Two programs were developed to ensure the accurate evaluation. BLUPF90 and MTDFREML were compared using the estimated solution. In relation to the pearson and spearman correlation, the estimated breeding value correlation coefficients were highest among all traits over 99.5%. Depending on the breeding value of the high correlation in Model I and Model II, accurate evaluation can be found. The number of iteration to convergence was 2,568 in Model I and 1,038 in Model II. The speed of solving was 256.008 seconds in Model I and 235.729 seconds in Model II. Model II had a speed of approximately 10% more than Model I. Therefore, it is considered to be much more effective to analyze large data through the improved algorithm than the existing method. If the corresponding program is systemized and utilized for the consulting of farm and industrial services, it would make contribution to the early selection of individual, shorten the generation, and cultivation of superior groups, and help develop the Hanwoo industry further through the improvement of breeding value based enhancement, ultimately paving the way for the country to evolve into an advanced livestock country.

    A Prediction Model for Removal of Non-point Source Pollutant Considering Clogging Effect of Sand Filter Layers for Rainwater Recycling (빗물 재활용을 위한 모래 정화층의 폐색특성을 고려한 비점오염원 제거 예측 모델 연구)

    • Ahn, Jaeyoon;Lee, Dongseop;Han, Shinin;Jung, Youngwook;Choi, Hangseok
      • Journal of the Korean Geotechnical Society
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      • v.30 no.6
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      • pp.23-39
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      • 2014
    • An artificial rainwater reservoir installed in urban areas for recycling rainwater is an eco-friendly facility for reducing storm water effluence. However, in order to recycle the rainwater directly, the artificial rainwater reservoir requires an auxiliary system that can remove non-point source pollutants included in the initial rainfall of urban area. Therefore, the conventional soil filtration technology is adopted to capture non-point source pollutants in an economical and efficient way in the purification system of artificial rainwater reservoirs. In order to satisfy such a demand, clogging characteristics of the sand filter layers with different grain-size distributions were studied with real non-point source pollutants. For this, a series of lab-scale chamber tests were conducted to make a prediction model for removal of non-point source pollutants, based on the clogging theory. The laboratory chamber experiments were carried out by permeating two types of artificially contaminated water through five different types of sand filter layers with different grain-size distributions. The two artificial contaminated waters were made by fine marine-clay particles and real non-point source pollutants collected from motorcar roads of Seoul, Korea. In the laboratory chamber experiments, the concentrations of the artificial contaminated water were measured in terms of TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) and compared with each other to evaluate the performance of sand filter layers. In addition, the accumulated weight of pollutant particles clogged in the sand filter layers was estimated. This paper suggests a prediction model for removal of non-point source pollutants with theoretical consideration of the physical characteristics such as the grain-size distribution and composition, and change in the hydraulic conductivity and porosity of sand filter layers. The lumped parameter ${\theta}$ related with the clogging property was estimated by comparing the accumulated weight of pollutant particles obtained from the laboratory chamber experiments and calculated from the prediction model based on the clogging theory. It is found that the lumped parameter ${\theta}$ has a significant influence on the amount of the pollutant particles clogged in the pores of sand filter layers. In conclusion, according to the clogging prediction model, a double-sand-filter layer consisting of two separate layers: the upper sand-filter layer with the effective particle size of 1.49 mm and the lower sand-filter layer with the effective particle size of 0.93 mm, is proposed as the optimum system for removing non-point source pollutants in the field-sized artificial rainwater reservoir.


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