• Title/Summary/Keyword: time-history analyses

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Development of Permanent Displacement Model for Seismic Mountain Slope (지진 시 산사면의 영구변위 추정식 개발)

  • Lee, Jong-Hoo;Park, Duhee;Ahn, Jae-Kwang;Park, Inn-Joon
    • Journal of the Korean Geotechnical Society
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    • v.31 no.4
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    • pp.57-66
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    • 2015
  • Empirical seismic displacement equations based on the Newmark sliding block method are widely used to develop seismic landslide hazard map. Most proposed equations have been developed for embankments and landfills, and do not consider the dynamic response of sliding block. Therefore, they cannot be applied to Korean mountain slopes composed of thin, uniform soil-layer underlain by an inclined bedrock parallel to the slope. In this paper, a series of two-dimensional dynamic nonlinear finite difference analyses were performed to estimate the permanent seismic slope displacement. The seismic displacement of mountain slopes was calculated using the Newmark method and the equivalent acceleration time history. The calculated seismic displacements of the mountain slopes were compared to a widely used empirical displacement model. We show that the displacement prediction is significantly enhanced if the slope is modeled as a flexible sliding mass and the amplification characteristics are accounted for. Regression equation, which uses PGA, PGV, Arias intensity of the ground motion and the fundamental period of soil layer, is shown to provide a reliable estimate of the sliding displacement. Furthermore, the empirical equation is shown to reliably predict the hazard category.

Seismic investigation of cyclic pushover method for regular reinforced concrete bridge

  • Shafigh, Afshin;Ahmadi, Hamid Reza;Bayat, Mahmoud
    • Structural Engineering and Mechanics
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    • v.78 no.1
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    • pp.41-52
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    • 2021
  • Inelastic static pushover analysis has been used in the academic-research widely for seismic analysis of structures. Nowadays, the variety pushover analysis methods have been developed, including Modal pushover, Adaptive pushover, and Cyclic pushover, in which some weaknesses of the conventional pushover method have been rectified. In the conventional pushover analysis method, the effects of cumulative growth of cracks are not considered on the reduction of strength and stiffness of RC members that occur during earthquake or cyclic loading. Therefore, the Cyclic Pushover Analysis Method (CPA) has been proposed. This method is a powerful technique for seismic evaluation of regular reinforced concrete buildings in which the first mode of them is dominant. Since the bridges have different structures than buildings, their results cannot necessarily be attributed to bridges, and more research is needed. In this study, a cyclic pushover analysis with four loading protocols (suggested by valid references) by the Opensees software was conducted for seismic evaluation of two regular reinforce concrete bridges. The modeling method was validated with the comparison of the analytical and experimental results under both cyclic and dynamic loading. The failure mode of the piers was considered in two-mode of flexural failure and also a flexural-shear failure. Along with the cyclic analysis, conventional analysis has been studied. Also, the nonlinear incremental dynamic analysis (IDA) method has been used to examine and compare the results of pushover analyses. The time history of 20 far-field earthquake records was used to conduct IDA. After analysis, the base shear vs. displacement in the middle of the deck was drawn. The obtained results show that the cyclic pushover analysis method is able to evaluate an accurate seismic behavior of the reinforced concrete piers of the bridges. Based on the results, the cyclic pushover has proper convergence with IDA. Its accuracy was much higher than the conventional pushover, in which the bridge piers failed in flexural-shear mode. But, in the flexural failure mode, the results of each two pushover methods were close approximately. Besides, the cyclic pushover method with ACI loading protocol, and ATC-24 loading protocol, can provided more accurate results for evaluating the seismic investigation of the bridges, specially if the bridge piers are failed in flexural-shear failure mode.

Seismic performance assessment of single pipe piles using three-dimensional finite element modeling considering different parameters

  • Duaa Al-Jeznawi;Jitendra Khatti;Musab Aied Qissab Al-Janabi;Kamaldeep Singh Grover;Ismacahyadi Bagus Mohamed Jais;Bushra S Albusoda;Norazlan Khalid
    • Earthquakes and Structures
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    • v.24 no.6
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    • pp.455-475
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    • 2023
  • The present study investigates the non-linear soil-pile interaction using three-dimensional (3D) non-linear finite element models. The numerical models were validated by using the results of extensive pile load and shaking table tests. The pile performance in liquefiable and non-liquefiable soil has been studied by analyzing the liquefaction ratio, pile lateral displacement (LD), pile bending moment (BM), and frictional resistance (FR) results. The pile models have been developed for the different ground conditions. The study reveals that the results obtained during the pile load test and shaking cycles have good agreement with the predicted pile and soil response. The soil density, peak ground acceleration (PGA), slenderness ratio (L/D), and soil condition (i.e., dry and saturated) are considered during modeling. Four ground motions are used for the non-linear time history analyses. Consequently, design charts are proposed depended on the analysis results to be used for design practice. Eleven models have been used to validate the capability of these charts to capture the soil-pile response under different seismic intensities. The results of the present study demonstrate that L/D ratio slightly affects the lateral displacement when compared with other parameters. Also, it has been observed that the increasing in PGA and decreasing L/D decreases the excess pore water pressure ratio; i.e., increasing PGA from 0.1 g to 0.82 g of loose sand model, decrease the liquefaction ratio by about 50%, and increasing L/D from 15 to 75 of the similar models (under Kobe earthquake), increase this ratio by about 30%. This study reveals that the lateral displacement increases nonlinearly under both dry and saturated conditions as the PGA increases. Similarly, it is observed that the BM increases under both dry and saturated states as the L/D ratio increases. Regarding the acceleration histories, the pile BM was reduced by reducing the acceleration intensity. Hence, the pile BM decreased to about 31% when the applied ground motion switched from Kobe (PGA=0.82 g) to Ali Algharbi (PGA=0.10 g). This study reveals that the soil conditions affect the relationship pattern between the FR and the PGA. Also, this research could be helpful in understanding the threat of earthquakes in different ground characteristics.

Supplementary Woodblocks of the Tripitaka Koreana at Haeinsa Temple: Focus on Supplementary Woodblocks of the Maha Prajnaparamita Sutra (해인사 고려대장경 보각판(補刻板) 연구 -『대반야바라밀다경』 보각판을 중심으로-)

  • Shin, Eunje;Park, Hyein
    • MISULJARYO - National Museum of Korea Art Journal
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    • v.98
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    • pp.104-129
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    • 2020
  • Designated as a national treasure of Korea and inscribed on the UNESCO World Heritage List, the Tripitaka Koreana at Haeinsa Temple is the world's oldest and most comprehensive extant version of the Tripitaka in Hanja script (i.e., Chinese characters). The set consists of 81,352 carved woodblocks, some of which have two or more copies, which are known as "duplicate woodblocks." These duplicates are supplementary woodblocks (bogakpan) that were carved some time after the original production, likely to replace blocks that had been eroded or damaged by repeated printings. According to the most recent survey, the number of supplementary woodblocks is 118, or approximately 0.14% of the total set, which attests to the outstanding preservation of the original woodblocks. Research on the supplementary woodblocks can reveal important details about the preservation and management of the Tripitaka Koreana woodblocks. Most of the supplementary woodblocks were carved during the Joseon period (1392-1910) or Japanese colonial period (1910-1945). Although the details of the woodblocks from the Japanese colonial period have been recorded and organized to a certain extent, no such efforts have been made with regards to the woodblocks from the Joseon period. This paper analyzes the characteristics and production date of the supplementary woodblocks of the Tripitaka Koreana. The sutra with the most supplementary woodblocks is the Maha Prajnaparamita Sutra (Perfection of Transcendental Wisdom), often known as the Heart Sutra. In fact, 76 of the total 118 supplementary woodblocks (64.4%) are for this sutra. Hence, analyses of printed versions of the Maha Prajnaparamita Sutra should illuminate trends in the carving of supplementary woodblocks for the Tripitaka Koreana, including the representative characteristics of different periods. According to analysis of the 76 supplementary woodblocks of the Maha Prajnaparamita Sutra, 23 were carved during the Japanese colonial period: 12 in 1915 and 11 in 1937. The remaining 53 were carved during the Joseon period at three separate times. First, 14 of the woodblocks bear the inscription "carved in the mujin year by Haeji" ("戊辰年更刻海志"). Here, the "mujin year" is estimated to correspond to 1448, or the thirtieth year of the reign of King Sejong. On many of these 14 woodblocks, the name of the person who did the carving is engraved outside the border. One of these names is Seonggyeong, an artisan who is known to have been active in 1446, thus supporting the conclusion that the mujin year corresponds to 1448. The vertical length of these woodblocks (inside the border) is 21 cm, which is about 1 cm shorter than the original woodblocks. Some of these blocks were carved in the Zhao Mengfu script. Distinguishing features include the appearance of faint lines on some plates, and the rough finish of the bottoms. The second group of supplementary woodblocks was carved shortly after 1865, when the monks Namho Yeonggi and Haemyeong Jangung had two copies of the Tripitaka Koreana printed. At the time, some of the pages could not be printed because the original woodblocks were damaged. This is confirmed by the missing pages of the extant copy that is now preserved at Woljeongsa Temple. As a result, the supplementary woodblocks are estimated to have been produced immediately after the printing. Evidently, however, not all of the damaged woodblocks could be replaced at this time, as only six woodblocks (comprising eight pages) were carved. On the 1865 woodblocks, lines can be seen between the columns, no red paint was applied, and the prayers of patrons were also carved into the plates. The third carving of supplementary woodblocks occurred just before 1899, when the imperial court of the Korean Empire sponsored a new printing of the Tripitaka Koreana. Government officials who were dispatched to supervise the printing likely inspected the existing blocks and ordered supplementary woodblocks to be carved to replace those that were damaged. A total of 33 supplementary woodblocks (comprising 56 pages) were carved at this time, accounting for the largest number of supplementary woodblocks for the Maha Prajnaparamita Sutra. On the 1899 supplementary woodblocks, red paint was applied to each plate and one line was left blank at both ends.

The Discourse on Girls and the Comics in the 1970s Magazine, Schoolgirl - A Forced Model and the Invented Cheerfulness (1970년대 잡지 『여학생』의 소녀 담론과 만화 -강요된 모범과 만들어진 명랑)

  • Kim, So-Won
    • Journal of Popular Narrative
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    • v.27 no.3
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    • pp.13-51
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    • 2021
  • The aim of this essay is to illustrate Sunjung Manhwa in the 1970s which has been alienated in comics studies. This essay analyses the articles and the serial comics in Schoolgirl, the magazine in the 1970s, and examines the ideal representations of the girls at that time. Sunjung Manhwa is really different between the 1960s and 1970s. It cannot be explained on this gap just by analyzing Sunjung Manhwa in book form alone. Even though the censorship on comics was the element that has hampered the development of comics as a whole, the slumps of Sunjung Manhwa in the 1970s were very excessive compared to other comics genres. This article can gain the answers to the reason of the changes of Sunjung Manhwa by studying the magazines which was the main mass media aimed at girls with Sunjung Manhwa. While the articles in magazines show the editing direction and its characteristics, they reflect the values and ideologies at that time. The same is true for the comics in the magazines. Especially, the comics in the magazines was relatively free from the censorship. This essay examined how the articles and the comics in the girls' magazine in the 1970s represented the images of girls at the time by focusing on feature articles and comics in the magazine, Schoolgirl. This article explored Um, Hee-Ja's Blue Zone and Bang, Young-Jin's Mini March among a full-length serial comics in the magazine, Schoolgirl. Both Blue Zone and Mini March reveal the images of an ideal girl that has been emphasized by the articles in Schoolgirl. Blue Zone draws the appearances of an earnest and obedient daughter, and Mini March represents the figures of a cheerful and bright girl. Through this study, it can be recognized that the magazines in the 1970s highly appraised girls who are obedient to a given society and serve to a harmonious family as ideal ones, and it might be guessed that the ideal images of girls that was characterized ceaselessly by the magazines were the standard of the censorship on comics and its creativity and had also a huge impact on the contents and the expressions of a great deal of works. The 1970s was the times when its importance has been lost in the history of the comics studies by the censorship on the comics and the monopoly of "Hapdong(합동) publisher." The limits of expression in terms of censorship were awfully distinct, so its result was few of good works in quality, and there are still many blanks in the study on 1970s' comics. This study has a meaning which fills up a blank in the comics studies.

The Effects of Kisaeng's Clothes on General Women's Fashion in the Late Choson Dynasty (조선후기 기여복식이 일반부녀자 복식에 미친 영향)

  • 김나형;김용서
    • Journal of the Korean Society of Costume
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    • v.39
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    • pp.113-123
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    • 1998
  • This study focuses on the effects of the clothes worn by kisaeng; courtesans trained in singing and dancing, on changes in female psychology as reflected in general women's fashions during the later years of the Chosun dynasty. During this period, the social order had broken down considerable, due in part to the introduction of Roman Catholicism, and in part to the actions of Sil-hak, who emphasized open-ness and practicality in the organization of social affairs. This freer social environment disrup-ted the established social hierarchies. The kisaeng were among the first to respond to the new social mores by adopting more colorful, sensual, and individualized fashions. Their social position allowed them to reflect the new aesthetics of the time right away. Those aesthetics seemed to lay great emphasis on the artistic effects of contrast. The kisaeng would adorn their heads with large Kache (an elaborate wig or hairdo typically reserved for use by women in full formal dress). In contrast to this conspicuous hairstyle, they typically wore very tight-fitting Jogori (short-cropped Korean traditional jackets for women) around their upper torsos. The long skirts emerging from beneath these short jackets would typically flare out dramatically, with the aid of petticoats. However, these skirts would be bound at the waist with a sash, increasing the sexual suggestiveness of the clothing by drawing at-tention to the hips, and by exposing the bottom frills of the petticoats, or the wide pantal-oons and other undergarments the kisaeng wore to add volume to their skirts. The relative freedom enjoyed by the kisaeng to experiment with new fashions was not widely shared by most women. This generated envy from women of the noble classes, who were more bound by convention, and restrained from adopting such a mode of dress. It also generated envy from women of the humble classes, who saw the kisaeng as working little for their wealth, and yet dressing every day in finery that the average women would only ever be able to afford on her wedding day. This envy directed at the relative freedom/wealth of the kisaeng by women who faced greater socioeconomic constraints was given cultural expression through the adoption of elements of the kisaeng's fashion in the fashions of both noblewomen and humble women in old korea. The luxurious Kache sported by the kisaeng had in fact been borrowed from the habitual attire of upper-class women. So to distinguish themeselves from the kisaeng, they began to abandon these elaborate hairstyles in favor of traditional ceremonial hoods (Nel-ul-a thin black women's hood) and coronets (Suegaechima). This supposed reaction to the abuse of the Kache by the kisaeng still remained influenced by the kisaeng still remained influence by the kisaeng, however, as these headdresses became adorned with many more jewels and decorations, in imitation of the kisaeng's adaptations of the coronet. At the same time, noblewomen began sporting the Jangwue ; a headdress previously worn only by kisaeng and lower class women, and lower class women were then permitted to wear the Kache at weddings. All women behan to wear shorter, tighter Jogori jackets, and to add volume to their skirts. They also attached frills to their under-garments in imitation of the kisaeng's exposed petticoats and pantaloons. The impact of kisaeng fashions was thus deep and widespread, and can be understood as an expression of women's longing for freedom from socioeconomic constraints in the late Chosun dynasty. This study adopts an interdisciplinary ap-proach to the understanding of historical changes in women's fashions. Such interdisciplinary work can greatly enrich the study of fashion, often narrowly focused on clothing morphology and broad generalizations about society. For this reason, specific dynamics of feminine psychology in the late Chosun dynasty were elaborated in this study, to provide a deeper under-standing of the changes in fashion underpinned by them. If more such detailed analyses are undertaken, a whole new understanding of changes in fashion can be generated, and perhaps a transformation of the field of fashion history can be ultimately achieved.

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A Study on Business Diversification and Business Performance of Korean Mass Media Enterprises (국내 매스미디어 기업의 사업다각화와 경영성과에 관한 연구)

  • Chang, Yun-Hi
    • Korean journal of communication and information
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    • v.43
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    • pp.173-208
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    • 2008
  • This study analyses the business performance according to the business diversification of Korean mass media enterprises from year 2003 to 2006. The conclusions drawn which could be divided into five main parts are the followings: First, newspaper companies pursue unrelated diversification in various industrial areas, in order to gain maximum profit while broadcasting companies exert themselves to provide better service by diversifying the major contents. Second, overall the interviewed companies display a constant decline in profit gained from their major business area thus establishing strategies to broaden their focus on diversification of any sort. Third, the researcher completed group analysis in regard of diversification measure resulting in division of three groups. The group which had the most immense diversification range gained the highest ROE, the lowest ROE volatility, and lesser probability of risk taking. The analysis adresses the companies broadening their business areas by researching and focusing on diversification are relatively stable in terms of the profit they gain. Fourth, the middle level group in terms of sales scale, debts, enterprise history, major share rate and high ROE group carry out diversification progressively. The sales scale affects positively to diversification, while the major share rate affects negatively to diversification. Fifth, in accordance to the research, diversification overall contributes to obtainance of successful outcome. Since there was not an immense amount of studies to be referred in the media area, the researcher interviewed and did panel discussion with numerous strategists and managers who are in charge of diversification of media companies. However, collection of only 4 years of data limits the research to be considered to be a generalized study, and does not reflect time gap between business diversification and business performance. Development is required in future studies to be established regarding the media companies' specificity different to other industries, classified the media companies into media types, and consider the time gap in the diversification activities and business performance.

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An Analysis of the Differences in Management Performance by Business Categories from the Perspective of Small Business Systematization (영세 소상공인 조직화에 대한 직능업종별 차이분석과 경영성과)

  • Suh, Geun-Ha;Seo, Mi-Ok;Yoon, Sung-Wook
    • Journal of Distribution Science
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    • v.9 no.2
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    • pp.111-122
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    • 2011
  • The purpose of this study is to survey the successful cases of small and medium Business Systematization Cognition by examining their entrepreneurial characteristics and analysing the factors affecting their success. To that end, previous studies on the association types of small businesses were studied. A research model was developed, and research hypotheses for an empirical analysis were established upon it. Suh et al. (2010) insist on the importance of Small Business Systematization in Korea but also show that small business performance is suffering: they are too small to stand alone. That is why association is so crucial for them: they must stand together. Unfortunately, association is difficult, as they have few specific links and little motivation. Even in franchising networks, association tends to be initiated by big franchisers, not small ones. In that sense, association among small businesses is crucial for their long-term survival. With this in mind, this study examines how they think and feel about the issue of 'Industrial Classification', how important Industrial Classification is to their business success, and what kinds of problems it raises in the markets. This study seeks the different cognitions among the association types of small businesses from the perspectives of participation motivation, systematization expectation, policy demand level, and management performance. We assume that different industrial classification types of small businesses will have different cognitions concerning these factors. There are four basic industrial classification types of small businesses: retail sales, restaurant, service, and manufacturing. To date, most of the studies in this area have focused on collecting data on the external environments of small businesses or performing statistical analyses on their status. In this study, we surveyed 4 market areas in Busan, Masan, and Changwon in Korea, where business associations consist of merchants, shop owners, and traders. We surveyed 330 shops and merchants by sending a questionnaire or visiting. Finally, 268 questionnaires were collected and used for the analysis. An ANOVA, T-test, and regression analyses were conducted to test the research hypotheses. The results demonstrate that there are differences in cognition depending upon the industrial classification type. Restaurants generally have a higher cognition concerning job offer problems and a lower cognition concerning their competitiveness. Restaurants also depend more on systematization expectation than do the other industrial classification types. On the policy demand level, restaurants have a higher cognition. This study identifies several factors that are contributing to management performance through differences in cognition that depend upon association type: systematization expectation and policy demand level have positive effects on management performance; participation motivation has a negative effect on management performance. We confirm also that the image factors of different cognitions are linked to an awareness of the value of systematization and that these factors show sequential and continual patterns in the course of generating performances. In conclusion, this study carries significant implications in its classifying of small businesses into the four different associational types (retail sales, restaurant, services, and manufacturing). We believe our study to be the first one to conduct an empirical survey in this subject area. More studies in this area will likely use our research frameworks. The data show that regionally based industrial classification associations such as those in rural cities or less developed areas tend to suffer more problems than those in urban areas. Moreover, restaurants suffer more problems than the norm. Most of the problems raised in this study concern the act of 'associating itself'. Most associations have serious difficulties in associating. On the other hand, the area where they have the least policy demand is that of service types. This study contributes to the argument that associating, rather than financial assistance or management consulting, promotes the start-up and managerial performance of small businesses. This study also has some limitations. The main limitation is the number of questionnaires. We could not survey all the industrial classification types across the country because of budget and time limitations. If we had, we could have produced many more useful results and enhanced the precision of our analysis. The history of systemization is very short and the number of industrial classification associations is relatively low in Korea. We should keep in mind, though, that this is very crucial to systemization entrepreneurs starting their businesses, as it can heavily affect their chances of success. Being strongly associated with each other might be critical to the business success of industrial classification members. Thus, the government needs to put more effort and resources into supporting the drive of industrial classification members to become more strongly associated.

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Fish Community Structure Analysis and Ecological Health Assessments in the Headwater Watershed of Nakdong River (낙동강 상류 수계의 어류 군집 구조 분석 및 생태건강도 평가)

  • Lee, Jae-Hoon;Hong, Young-Pyo;An, Kwang-Guk
    • Korean Journal of Ecology and Environment
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    • v.40 no.3
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    • pp.403-411
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    • 2007
  • The purpose of the study was to evaluate fish community, based on conventional at Shannon-Weaver diversity index (H'), and ecological health, based on the Index of Biological Integrity (IBI) using fish assemblage in the eight sites of Nakdong River during June${\sim}$August 1999. Total number of species sampled was 19 species, and two sensitive species of Zacco temminckii (51%) and Rhynchocypris oxycephalus (28%) dominated the fish community. Also, trophic guild analyses showed that insectivore was 87% of the total and omnivore was rare, indicating that the ecological health is well maintained in the system. The pattern of spatial variation in the diversity index(H') was very similar to patterns of the species number and individual number, whereas the pattern of H' was not matched with the tolerance and trophic guild data. The diversity index (H') showed highest (1.56) in Site 6 where the proportion of sensitive species and tolerant species was minimum and maximum, respectively, and where the insectivore and omnivore were minimum and maximum. In other words, the diversity index was not matched at all with the trophic and tolerant guilds, indicating that the conventional index did not reflect the ecological characteristics of fish community in the system. In the mean time, the ecological health (IBI) averaged 33.5 (n=8), indicating "good${\sim}$fair condition" and the IBI values matched with trophic and tolerance guilds. Maximum IBI occurred in Site 2 where the sensitive and msectivore species were nearly maximum, and the tolerant and omnivore species were almost minima, indicating that IBI values were closely associated with the ecological functions and health conditions. Overall data suggest that the conventional diversity index may not effective for a evaluation of fish community, and that in contrast the IBI approach may be a useful tool for diagnosis of stream community.