• Title/Summary/Keyword: Variance of Analysis

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Structural features and Diffusion Patterns of Gartner Hype Cycle for Artificial Intelligence using Social Network analysis (인공지능 기술에 관한 가트너 하이프사이클의 네트워크 집단구조 특성 및 확산패턴에 관한 연구)

  • Shin, Sunah;Kang, Juyoung
    • Journal of Intelligence and Information Systems
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    • v.28 no.1
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    • pp.107-129
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    • 2022
  • It is important to preempt new technology because the technology competition is getting much tougher. Stakeholders conduct exploration activities continuously for new technology preoccupancy at the right time. Gartner's Hype Cycle has significant implications for stakeholders. The Hype Cycle is a expectation graph for new technologies which is combining the technology life cycle (S-curve) with the Hype Level. Stakeholders such as R&D investor, CTO(Chef of Technology Officer) and technical personnel are very interested in Gartner's Hype Cycle for new technologies. Because high expectation for new technologies can bring opportunities to maintain investment by securing the legitimacy of R&D investment. However, contrary to the high interest of the industry, the preceding researches faced with limitations aspect of empirical method and source data(news, academic papers, search traffic, patent etc.). In this study, we focused on two research questions. The first research question was 'Is there a difference in the characteristics of the network structure at each stage of the hype cycle?'. To confirm the first research question, the structural characteristics of each stage were confirmed through the component cohesion size. The second research question is 'Is there a pattern of diffusion at each stage of the hype cycle?'. This research question was to be solved through centralization index and network density. The centralization index is a concept of variance, and a higher centralization index means that a small number of nodes are centered in the network. Concentration of a small number of nodes means a star network structure. In the network structure, the star network structure is a centralized structure and shows better diffusion performance than a decentralized network (circle structure). Because the nodes which are the center of information transfer can judge useful information and deliver it to other nodes the fastest. So we confirmed the out-degree centralization index and in-degree centralization index for each stage. For this purpose, we confirmed the structural features of the community and the expectation diffusion patterns using Social Network Serice(SNS) data in 'Gartner Hype Cycle for Artificial Intelligence, 2021'. Twitter data for 30 technologies (excluding four technologies) listed in 'Gartner Hype Cycle for Artificial Intelligence, 2021' were analyzed. Analysis was performed using R program (4.1.1 ver) and Cyram Netminer. From October 31, 2021 to November 9, 2021, 6,766 tweets were searched through the Twitter API, and converting the relationship user's tweet(Source) and user's retweets (Target). As a result, 4,124 edgelists were analyzed. As a reult of the study, we confirmed the structural features and diffusion patterns through analyze the component cohesion size and degree centralization and density. Through this study, we confirmed that the groups of each stage increased number of components as time passed and the density decreased. Also 'Innovation Trigger' which is a group interested in new technologies as a early adopter in the innovation diffusion theory had high out-degree centralization index and the others had higher in-degree centralization index than out-degree. It can be inferred that 'Innovation Trigger' group has the biggest influence, and the diffusion will gradually slow down from the subsequent groups. In this study, network analysis was conducted using social network service data unlike methods of the precedent researches. This is significant in that it provided an idea to expand the method of analysis when analyzing Gartner's hype cycle in the future. In addition, the fact that the innovation diffusion theory was applied to the Gartner's hype cycle's stage in artificial intelligence can be evaluated positively because the Gartner hype cycle has been repeatedly discussed as a theoretical weakness. Also it is expected that this study will provide a new perspective on decision-making on technology investment to stakeholdes.

A Study on Balanced -type Oseillating Mole-Drainer(III)-Model Test for Draft Force, Torque, Power and Moment (평행식 진동탄환 암거 천공기의 연구(III)-견인력, 토크, 동력 및 모멘크에 관한 모형시험-)

  • 김용환
    • Journal of Biosystems Engineering
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    • v.1 no.1
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    • pp.1-6
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    • 1976
  • This paper is the third one of the study on balanced type oscillating mole-drainer, the first one was presented in No 9. Gyeongsang College Report and the second one in Vol. 17, No.4 of the KSAE. In the first part of this study, the characteristics of traction forces between the nonoscillating earth working equipments and oscillating ones was compared. A model of the balanced type oscillating mole-drainer, which composed of a mechanism that may reduce the machine vibration, was designed following the dimensional analysis and similitude technique. The model test was carried out to clarify the balancing mechanism of the oscillating parts and other parts of the machine. In the light of the results from the model tests, a prototype machine was made for experimental purpose. Results from the field test by a reported in the near future. In the second report, the model tests were carried out under the same soil conditions, i.e, . oscillating frequency, running velocity, and oscillating amplitude, etc. It was clear that use of balanced type oscillating model could substantially reduce the vibration of the whole system of the machine, when compared with the nonoscillating type model. In this paper(the third report), results of investigation on the traction force, power requirement, and moment. etc, is presented. Analysis of variance technique was used for analyzing the effect of the frequency, amplitude, and running velocity on the draft force, torque, power requirements, and moments. The results obtained from the model tests are as follows, 1) By practicing a balanced-type oscillating mole-drainer, it was possible to reduce the traction resistance by 55.1-61. 2 percent of traction resistance, however, was 1.75 - 1.95 times greater than the value of resistance which was induced by use of a mole-drainer with single bullet. The resistance of rear shank against soil was considered as a main causing factor of the above results. 2) As the oscillation frequency was increased, the traction resistance was decreased. Considering on the effect of oscillation the greater the amplitude, and the slower the running velocity was, the greater the reduction ratio of traction resistance was. 3) The ratio of the traction resistance of oscillating mole-drainer to that of non-oscillating one could be represented as a function of dimensionless variable (V/$Af$). The results from the tests were well agreed with the reported results from the experim ents on oscillation plow or hoe. 4) By taking a lower value of (V/$Af$), reducing the traction resistance was possible. This fact meant, however, that the efficiency of mole drain practice would be lower. 5) It was experimentally confirmed under the same condition of soil that the variable (R/$rD1^3$) could be represented as a function of a variable($V^2/gD$) when a non\ulcornerocillating mole-drainer was used. 6) When a oscillating mole-drainer was used, the variable(R/$rD_1^{3}$) could be represented as a function of two variables ($v^2/gD_1$) and (V^2/gD_1$). 7) The torque was not affected by a change of frequency. However, a relation of proportionality existed between torque and amplitude, running velocity, and ratio of bullet diameter. When a balanced type oscillating mole-drainer with two bullets was used, torque was increased by 52.8-78. 4 percent and total power requirement was also increased. 8) Total power requirement was increased linearly in accordance with the increasing frequency, 41.96 percent of total power was used for oscillating action. The magnitude of total power requirement was 1. 8-9. 4 times greater than that of a non-oscillating mechanism. In the view point of power requirement, it was not advisable to increase the frequency, amplitude, running velocity, and ratio of bullet diameter at the same time. 9) Only the positive moment occured in the rear shank. Change of the diameter of a rear bullet, could not affect the balancing against the soil resistance. It was necessary for rear bullet to have a large resistance against soil only when the rear bullet was in backward motion. 10) Within an extent of the experimental base, optimum limits for several design factors were A=0.5cm, $f$=22.5Hz, V=O. 05m/sec, and $\lambda$=1.0 By adapting these values traction resistance was reduced by 40 percent and vibration acceleration wa s reduced by 60 percent. Even though the total , power requirements for operating a balanced type oscillation mechanism was greater ~than that of non-oscillating one, using a oscillating mechanism would be more effective. Because a balanced type oscillating mechanism is used, tractive resistance will be reduced and then the lighter . tractive equipment could be used.

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A Study on the Functional Status in Life and Life Satisfaction for Elderly Residing at Home - Comparing Urban and Rural Elderly - (재택노인의 생활기능상태와 생활만족도에 관한 연구)

  • 이재면
    • Korean Journal of Health Education and Promotion
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    • v.12 no.2
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    • pp.109-119
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    • 1995
  • As the population of elderly in Korea is increasing rapidly since the 1990's and will more rapidly in the 21st Century, the demand of their health care would be a great burden to health care expenditure. Then it would be necessary to contemplate the functional status and life satisfaction for elderly to make them live more independently. The objectives of this study were find out the functional status in life and life satisfaction for the elderly aged 65 or over who had resided in urban area of two Gus in Pusan and rural area of two Myuns in Haman Gun in Kyeognam Province, and to provide basic data for planning systematic health care programme. The study period was two weeks from February 6 to February 18, 1995 and the subjects were 274 elderly of which 143 were urban residents, 131 were rural residents, and the study method was by structured questionnaire. The data were analyzed with SAS/PC/sup +/ programme using Chi-square test, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression analysis. The results were as follows; 1. To see the pattern of living together, those living with partners were the most common, 39.1% ; 37.8% of urban elderly lived with married sons, 32.2% of them lived with partners, but 46.6% of rural elderly lived with partners, 16.8% of them lived with married sons, which showed difference between residence(p<0.005). 2. Elderly who had jobs were 64.1% in rural residents, and 7.7% in urban residents, which showed significant difference(p<0.05). 3. The score of cognitive function of total subjects was 24.7, that of urban elderly was 23.8, and that of rural elderly was 25.7, then it was higher in rural ones and low for old-elders and those who had no jobs. 4. The score of PADL was 26.8 for urban elderly, 30.1 for rural elderly, and that of IADL was 22.2 for urban elderly, 25.6 for rural elderly, which showed higher activities of daily living for rural elderly than urban elderly(p<0.001). 5. The score of domestic performance was 21.9 for urban elderly, and 30.5 for rural elderly, which showed higher score for rural elderly(p<0.001). 6. The score of life satisfaction was 20.7 for urban elderly, 29.8 for rural elderly, then it was higher for rural elderly(p<0.01). 7. As a result of ANOVA for functional status in living by general characteristics; the score of cognitive function differed by age, job; that of PADL differed by age, job, education, and the pattern of living together, that of IADL differed by age, job, and the pattern of living together. The score of domestic role performance differed by age, job, marital status, and the pattern of living together. 8. ANOVA for life satisfaction showed that the score of life satisfaction differed by job(p<0.001) and the pattern of living together(p<0.01). 9. The correlations between functional status in living and life satisfaction showed that the higher the score of cognitive function was(r=0.39), the higher the score of activities of daily living was(r=0.50), and the higher the score of domestic role performance was(r=0.41), the higher the score of life satisfaction. 10. Stepwise multiple regression analysis for life satisfaction pointed out that residence was responsible for 39.9% of the variance. cognitive function was for 5.3%, and domestic role performance was for 1.2%.

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Psychosocial Characteristics and Quality of Life in Patients with Functional Gastrointestinal Disorder (기능성위장질환 환자들의 정신사회적 특성과 삶의 질)

  • Lee, Dong-Ho;Lee, Sang-Yeol;Ryu, Han-Seung;Choi, Suck-Chei;Yang, Chan-Mo;Jang, Seung-Ho
    • Korean Journal of Psychosomatic Medicine
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    • v.28 no.1
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    • pp.20-28
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    • 2020
  • Objectives : The aim of this study was to compare psychosocial characteristics of the functional gastrointestinal disorders FGID group, non-FGID group, and control group and determine factors affecting the QOL of patients with FGID. Methods : 135 patients diagnosed with FGID were selected. 79 adults had no observable symptoms of FGID (control group) and 88 adults showed symptoms of FGID (non-FGID group). Demographic factors were investigated. The Korean-Beck Depression Inventory-II, Korean-Beck Anxiety Inventory, Korean-Childhood Trauma Questionnaire, Multidimensional Scale of Perceived Social Support, Connor-Davidson Resilience Scale, Patient Health Questionnaire-15 and WHO Quality of Life Assessment Instrument Brief Form were used to assess psychosocial factors. A one-way ANOVA was used to compare differences among groups. Pearson correlation test was performed to analyze the correlation of psychosocial factors and QOL of the FGID group. Further, a hierarchical regression analysis was conducted to determine factors affecting the QOL of the FGID group. Results : Between-group differences were not significant in demographic characteristics. Depression (F=48.75, p<0.001), anxiety (F=14.48, p<0.001), somatization (F=24.42, p<0.001) and childhood trauma (F=12.71, p<0.001) were significantly higher in FGID group than in other groups. Social support (F=39.95, p<0.001) and resilience (F=17.51, p<0.001) were significantly lower in FGID group than in other groups. Resilience (β=0.373, p<0.01) was the most important explanatory variable. The explained variance was 47.2%. Conclusions : Significantly more symptoms of depression, anxiety, childhood trauma, and somatization were observed for the FGID group. This group also had less social support, resilience, and quality of life than the non-FGID and control groups. The key factor for quality of life of the FGID group was resilience.

BIOMECHANICS OF ABUTMENTS SUPPORTING REMOVABLE PARTIAL DENTURES UNDER UNILATERAL LOADING

  • Kim, Seong-Kyun;Heo, Seong-Joo;Koak, Jai-Young;Lee, Jeong-Taek;Roh, Hyun-Ki;Kim, Hyo-Jin;Lee, Seok-Hyung;Lee, Joo-Hee
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.6
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    • pp.753-759
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    • 2007
  • Statement of problem. In distal extension removable partial denture, the preservation of health of abutment teeth is very important, but abutment teeth are subjected to unfavorable stress under unilateral loading specially. Purpose. The purpose of this study was to investigate the biomechanical effects of mandibular removable partial dentures with various prosthetic designs under unilateral loading, using strain gauge analysis. Material and methods. Artificial teeth of both canines were anchored bilaterally in a mandibular edentulous model made of resin. Bilateral distal extension removable partial dentures with splinted and unsplinted abutments were fabricated. Group 1: Clasp-retained mandibular removable partial denture with unsplinted abutments Group 2: Clasp-retained mandibular removable partial denture with splinted abutments by 6-unit bridge. Group 3: Bar-retained mandibular removable partial denture Strain gauges were bonded on the labial plate of the mandibular resin model, approximately 2 mm dose to the abutments. Two unilateral vertical experimental loadings (30N and 100N) were applied subsequently via miniature load cell that were placed at mandibular left first molar region. Strain measurements were performed and simultaneously monitored from a computer connected to data acquisition system. For within-group evaluations, t-test was used to compare the strain values and for between-group comparisons, a one-way analysis of variance (ANOVA) was used and Tukey test was used as post hoc comparisons. Results. The strain values of group 1 and 2 were tensile under loadings. In contrast, strain values of group 3 were compressive in nature. Strain values increased as the applied load in increased from 30N to 100N (p<.05) except for right side in group 1. Under 30N loading, in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 100N loading in left side, group 1 showed higher strain values than groups 2 and 3 in absolute quantity (p<.05). And group 2 showed higher strain values than group 1 (p<.05). In right side, group 1 and 2 showed higher strain values than group 3 in absolute quantity (p<.05). Under 30N loading, group 2 and 3 showed higher strain values in right side than in left side. Under 100N loading, right side strain values were higher than left side ones for all groups. Conclusion. Splinting of two isolated abutments by bridge reduced the peri-abutment strain in comparison with unsplinted abutments under unilateral loading. Bar-retained removable partial denture showed the lowest strain of three groups, and compressive nature.

The Validation Study of Beck Depression Scale 2 in Korean Version (한국판 벡 우울 척도 2판의 타당화 연구)

  • Lim, Sun-Young;Lee, Eun-Jeong;Jeong, Seong-Won;Kim, Hee-Chul;Jeong, Cheol-Ho;Jeon, Tae-Yeon;Yi, Min-Soo;Kim, Jae-Min;Jo, Hyeon-Ju;Kim, Jeong-Beom
    • Anxiety and mood
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    • v.7 no.1
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    • pp.48-53
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    • 2011
  • Objective : Korean Version of Beck-II Depression Inventory to verify the reliability and validity of the proposed standards are practical and standardized, cut-off score by establishing a baseline indicating the presence of depression and depression On in the evaluation was to evaluate the clinical usefulness. Methods : 739 patients with major depression using the SCID and normal controls were 302 study subjects. Of patients with clinically significant medical condition, or psychotic disorders, organic mental disorder, epilepsy or seizure disorder, eating disorders are associated with patients taking anti-convulsants experienced in the past, patients were excluded from the study. Results : The main findings of this study were as follows. First, with respect to the KBDI-II items, the correlation between them ranged from 0.51 to 0.74, and was 0.60 over all questions. Further, the overall correlation of the KBDI-II plates showing confidence 'normal' than it was verified that. Second, the BDIII was used in each group to examine internal consistency and thus, whether Cronbach's alpha values were greater than 0.94. Third, the principal component analysis sought to extract factors in a way consistent with the results inspected last 3 factors were extracted and the total variance explained was 47.3%. Fourth, the Cutting calculated the score on the KBDI-II for ROC (Receiver operator characteristic) analysis yielding 18 dot, with the highest sensitivity and specificity was seen. Conclusion : Based on the results of this Study, the KBDI-II cut-off point should be valid as prescribed in 18 is considered.

Reconsideration of Acer pictum complex in Korea (한국산(韓國産) 고로쇠분류군(分類群)에 대한 재고(再考))

  • Chang, Chin-Sung
    • Korean Journal of Plant Taxonomy
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    • v.31 no.3
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    • pp.283-309
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    • 2001
  • Acer pictum complex (A. pictum Thunb. ex Murray with varieties, A. okamotoanum Nakai, A. truncatum Bunge) in eastern Asia causes frequent difficulty in identification. One hundred twenty five specimens from A. pictum complex of China, Korea and Japan and A. cappadocicum var. sinicum of China were compared to investigate patterns of intra- and interspecific variation and to evaluate a recognition of several species as well as many varieties using 22 characters for morphometric analysis. The first three PCA accounted for 59% of the total variance. No strong discontinuities existed among taxa with respect to fruit and leaf characters. Much overlap among all taxa occurred the central region of the scatter diagram. Many characters appeared to show some clinal variation with changes from east of China to Japan through Korea. This was true not only when all species as considered as a single taxon, but when characters of individual taxa were compared with geography. As one considers a path from the western part of the ranges to areas to the east, the leaves become larger in most respects and become increasingly many lobed (five to seven or nine). In general, there was a tendency toward larger nutlet with smaller wing in the area toward northeast of China (=A. truncatum), while in the east of ranges (Island Ullung-do), plants were larger with respect to characters of fruit and leaves (=A. okamotoanum). The morphological differentiation between A. okamotoanum and Japanese and Korean individuals of A. pictum was not considered sufficient to warrant recognition of either specific or varietal status and should be treated as con specific under A. pictum var. mono. Since the lectotype of Acer pictum had minute hairs uniformly on the under surface of leaves(A. pictum var. pictum), the glabrous type of A. pictum was called A. pictum var. mono as Ohahsi suggested. The univaraite analysis (the mean and maximum/minium of nutlet size and wing/nutlet length ratio) indicated geographical differentiation of northeastern populations, A. truncatum, was distinctive, but Korean individuals of A. truncatum showed an affinity between Chinese individuals of A. truncatum and Korean individuals of A. Pictum var. mono. The current results, together with qualitative character, trunk features, justify subspecific status for this taxon. The previous varieties of A. mono in Korea were indistinguishable from typical form of A. Pictum var. mono on the basis of the wing angle and nutlet size, rejecting continued recognition of these taxa as distinctive varieties. Therefore, it is recommended that only one polymorphic species of A. pictum be recognized in addition to three varieties.

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An Empirical Study on Classification, Business Type, Organizational Culture on Performance of Korean IT SMEs·Venture (중소·벤처기업의 업종, 영업형태, 조직문화가 기업성과에 미치는 영향에 관한 연구: 삼원분산분석(3-way ANOVA)을 중심으로)

  • Roh, Doo-Hwan;Hwang, Kyung-Ho
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.14 no.2
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    • pp.221-233
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    • 2019
  • In Korea, small and medium sized domestic enterprises(SMEs) play an pivotal role in the national economy, accounting for 99.9% of all enterprises, 87.9% of total employment, and 48.3% of production. and SMEs was driving a real force of the development of national economy in many respects such as innovation, job creation, industrial diversity, balanced regional development. Despite their crucial role in the national development, most of SMEs suffer from a lack of R&D capabilities and equipments as well as funding capacity. Public R&D institutes can provide SMEs with valuable supplementary technological knowledge and help them build technological capacity. so, In order to effectively support SMEs, government and public R&D institutes must be a priority to know about the factors influencing the performance related to technology transfer and technological collaborations. In particular, SMEs are not only taking up a large portion of the national economy, but also their influence in politics and economy so strong that raising the competitiveness of small and medium-sized companies is a national policy goal that must be achieved in order to achieve sustained economic growth. For this reason, it is necessary to look specifically at the relationship between concepts such as the environment, strategy, and organizational culture surrounding the enterprise to enhance the competitiveness of SMEs. The paper analyzes 665 companies to find out which organizational culture affects their performance by classification and type of business of SMEs. This study demonstrated that when SMEs seek consistency in their external environment, strategies, and organizational structure to maintain their continued competitiveness. According to three-way analysis of variance (3-way ANOVA) indicates that classification of industries in SMEs has statistically significant main effects, but the type of business and organizational culture do not have significant effects. However, the company's organizational performance (operating profit) of SMES were found to differ significantly in comparison between groups according to classification standards of industries, and therefore adopted some parts. In addition, an analysis of the effect of interaction between the three independent variables of small and medium-sized enterprises has shown that there are statistically significant interaction effects among classification, types of business, and organizational cultures. The results shows that there is an organizational culture suitable for each industry classification and type of business of an entity, and is expected to be used as a basis for establishing promotion policies related to the incubation and commerciality of small and medium-sized venture companies in the future.

An Analysis of Termite(R. speratus kyushuensis) Damage to Nationally Designated Wooden Architectural Heritage in Korea (국가지정 목조건축문화재의 흰개미(R. speratus kyushuensis) 피해 현황 분석)

  • KIM, Sihyun;CHUNG, Yongjae
    • Korean Journal of Heritage: History & Science
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    • v.55 no.2
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    • pp.102-111
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    • 2022
  • Termites are a group of social insects that are one of the primary causes of damage to wooden architectural heritage. Since termite damage impairs the authenticity and structural stability of cultural heritage, it is imperative to prevent it. This study examines the extent of termite damage to wooden architectural heritage as part of efforts to prevent termite damage to nationally designated wooden architectural heritage sites across the country. The extent of termite damage to each cultural heritage was assessed qualitatively and quantitatively and comparatively analyzed by region using the results of the "Investigation on Biological Damage to Wooden Architectural Heritages" conducted by the National Research Institute of Cultural Heritage from 2016 to 2019. It involved 362 nationally designated wooden architectural heritages(25 national treasures, 157 treasures, 180 national folklore cultural heritages) and 1,104 buildings. The results were as follows: termite detection dogs reacted at 317(87.6%) of the 362 wooden heritages, with visible termite damage observed in 185 cases(51.1%). Furthermore, termite damage was confirmed using one of two methods(detection dogs or visual inspection) in 324 cases(89.5%). Of the 1,104 buildings, termite detection dogs reacted at 668(60.5%), while 339(30.7%) showed visible termite damage. Employing one of the two methods, damage was confirmed in 702 buildings(63.6%). The country was categorized into nine regions(Seoul Metropolitan Area, Gangwon, Chungbuk, Chungnam, Jeonbuk, Jeonnam, Gyeongbuk, Gyeongnam, and Jeju) to examine the termite damage rate and the degree of damage to each cultural heritage according to location. Termite detection dogs reacted to more than 70% of the cultural heritage in all regions. Visible damage was minimal in the Seoul metropolitan area(32.1%) and Gangwon(21.4%) but severe in Chungnam(65.6%), Jeonnam(67.3%), and Gyeongnam(68.2%). By quantifying the degree of termite damage of each cultural heritage as a ratio of the absence of termite damage among the total absence, the average termite damage of the cultural heritage across the country was 9.2%. Regional variance analysis showed that the cultural heritage in Jeonbuk and Jeonnam showed a statistically significantly higher degree of termite damage than the cultural heritage in the Seoul metropolitan area, Chungbuk, and Gyeongbuk. This paper comprehensively analyzed termite damage to nationally designated wooden architectural heritage. The findings are expected to be valuable in establishing policies for the preservation and management of cultural heritage sites in the future.

Trace Metals in Surface Sediments of Garolim Bay, Korea (가로림만 표층 퇴적물 내 미량금속 분포 특성)

  • PARK, KYOUNGKYU;CHOI, MANSIK;JOE, DONGJIN;JANG, DONGJUN;PARK, SOJUNG
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.25 no.2
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    • pp.9-25
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    • 2020
  • In 2010 and 2015, total 77 surface sediment samples were collected to assess the anthropogenic effects of trace metals in surface sediments of Garolim Bay, and the physical characteristics (particle size and specific surface area) and geochemical components (major (Al, Ca, Fe, K, Ba) and trace metals (Mn, Cs, Cr, Co, Ni, Cu, Zn, Pb), organic carbon and calcium carbonate) were analyzed. Mean grain size of Garolim Bay surface sediments ranged from 0.51-5.58 Ø (mean 3.98 Ø) and increased from the inlet of bay to the inner bay, and from the waterway to the land. Most of the metal concentrations except for some elements showed the similar distribution to those of mean grain size and specific surface area. As the particle size decreased and the specific surface area increased, the metal concentration increased. In order to estimate the factors controlling the concentration of trace metals, factor analysis was performed, and three factors were extracted (92.7% of the total variation). Factor 1 accounted for 71.3% of the total variation, which was a grain size factor. Factor 2 accounted for 14.2% of the total variation, Factor 3 accounted for 7.2% of the total variance. Enrichment factor was calculated using the particle size corrected background concentration. Metals with a enrichment factor of 1.5 or higher and the number of samples were 4 for Cr (St. 1, 16, 27, 39) and 1 for Pb (St. 39), but there were little differences in the concentrations of 1M HCl leached metals for these metals. The percentage of 1M HCl leached fraction to total metal concentration decreased in the order of Pb~Co>Cu>Zn~Mn>Ni>Cr. Comparing this value with contaminated and clean sediments in other coastal areas, the percentages for each metal were similar regardless of the trace metal levels in all regions. This fact might be resulted from the reaction between the 1M HCl solution and the different sediment constituents, indicating that there is a limit to apply this percentage of leached metal to the estimation of the contamination extent.