• Title/Summary/Keyword: K-means 군집분석

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Improving University Homepage FAQ Using Semantic Network Analysis (의미 연결망 분석을 활용한 대학 홈페이지 FAQ 개선방안)

  • Ahn, Su-Hyun;Lee, Sang-Jun
    • Journal of Digital Convergence
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    • v.16 no.9
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    • pp.11-20
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    • 2018
  • The Q&A board is widely used as a means of communicating service enquiries, and the need for efficient management of the enquiry system has risen because certain questions are being repeatedly and frequently registered. This study aims to construct a student-centered FAQ, centered on the unstructured data posted on the university homepage's Q&A board. We extracted major keywords from 690 postings registered in the recent 3 years, and conducted the semantic network analysis to find the relationship between the keywords and the centrality analysis in order to carry out network visualization. The most central keywords found through the analysis, in order of centrality, were application, curriculum, credit point, completion, graduation, approval, period, major, portal, department. Also, the major keywords were classified into 8 groups of course, register, student life, scholarship, library, dormitory, IT and commute. If the most frequent questions are organized into these areas to form the FAQ, based on the results above, it is expected to contribute to user convenience and the efficiency of administration by simplifying the service enquiry process for repeated questions, as well as enabling smooth two-way communication among the members of the university.

Study about Library and Information Center's Image of Library and Information Science Students as Workplace (문헌정보학과 학생의 직장으로서의 도서관·정보센터 이미지 분석)

  • Cho, Jane;Lee, Jiwon
    • Journal of the Korean Society for Library and Information Science
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    • v.50 no.3
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    • pp.113-132
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    • 2016
  • Positioning technique which has been widely used for making marketing strategy by analyzing customer's image also has been used for public and test-taker's image analysis about public facilities, entrepreneurs, universities. This study analyze image of library and Information science students who trying to find a job in library fields about diverse types of library and information centers by Positioning technique. As a result of Similarity cognition analysis by multidimensional Scaling and K-means clustering, it was found that students recognize that public, national, university, school library are similar, on the other hand, portal company and special library are different from those types. In the jobs, user service jobs and technical service jobs are recognized as separated clusters, and cultural program job is also recognized dissimilarly from those clusters. By the way, images about work satisfaction and stability of employment shows high in national library; high wage shows high in portal company; employee's growth potential shows high in special library; job importance shows high in reference service jobs; difficulty shows high in content's job. Anyway, in the workplace selection, almost students regard stability of employment as top priorities, accordingly they prefers public library at most. Such a preference concentration tendency is strongly appeared in local university students than in metropolitan area students as a result of Pearson's chi-square test.

The Development of a Sampling Instrument for Aquatic Organisms in Rice Paddy Fields: Submerged Funnel Traps with Attractants (논 생태계 서식 수서생물 채집 도구 개발: 유인제를 사용한 수중트랩)

  • Yoon, Sung-Soo;Kim, Myung-Hyun;Choi, Soon-Kun;Eo, Jinu;Kwon, Soon-Ik;Song, Young-Ju
    • Korean Journal of Environmental Biology
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    • v.35 no.4
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    • pp.640-647
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    • 2017
  • The need for an efficient sampling technique to collect aquatic organisms has risen with the increase of interest in rice paddy fields, which have been recognized as important ecosystems supporting biodiversity. In the present study, a submerged funnel trap used with the assistance of attracting agents (fish meal and chemical light) was designed as an easy, objective and quantitative tool for collecting aquatic organisms in the rice paddy fields. The preference for collecting aquatic organisms as a means for attracting agents was analyzed using a generalized linear mixed model. Also, based on the data of previous research, we compared the community composition of the aquatic macroinvertebrates, which were collected using the quadrat method, and newly designed submerged funnel traps, by analyzing non-metric multidimensional scaling. The results showed that the catching efficiency of 18 of the total 65 taxa was affected by the attracting agents. 12 taxa including Pomacea canaliculata, Hippeutis cantori, Austropeplea ollula, Erpobdella lineata, Ostracoda spp. Branchinella kugenumaensis, Hydaticus grammicus, Rhantus pulverosus, Chironomidae spp., Rana nigromaculata, Cobitidae spp. etc., favored fish meal and 6 taxa including Ischnura asiatica, Coenagrionidae spp. Sternolophus rufipes etc., were attracted by chemical light. The submerged funnel trap used as a measurement tool for biodiversity was less applicable than the quadrat method; however, it was more effective for the selective collection of specific taxa. We expect that this newly designed trap can be a simple and quantitative method for collecting aquatic organisms, and could be used for long term and extensive surveys in rice paddy fields in the future.

Ecological Characteristic between the Re-introduction Population and the Original Population (Jojong Stream, Sudong Stream) of Zacco koreanus in the Bongseonsa Stream, Korea (봉선사천의 참갈겨니(Zacco koreanus) 재도입 개체군과 원개체군(조종천, 수동천) 간 생태학적 특징)

  • Wang, Ju-Hyoun;Choi, Jun-Kil;Lee, Hyuk-Je;Lee, Hwang-Goo
    • Korean Journal of Environment and Ecology
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    • v.31 no.6
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    • pp.537-548
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    • 2017
  • The purpose of this study was to investigate the species composition and the aquatic environment of Jojong Stream and Sudong Stream, which were the original habitats of Zacco koreanus population and restored population re-introduced in Bongseonsa Stream. It also compared and analyzed the states of the growth and reproductive ability of Z. koreanus habiting in each of the three streams. The investigation was conducted in June 2016 which was known as the spawning season of Z. koreanus. The results of the physical aquatic environments showed the slight differences in altitude, width and depth of water among three streams, but the bottom structure was found to be quite different in the composition of the boulder, cobble, and pebble among the streams. The result of the physicochemical aquatic environment analysis showed that there were no significant differences in water temperature, pH, DO, BOD, and EC among the three stream. In the fish fauna investigation, 530 individuals of 11 species of 3 families were collected in Bongseonsa Stream, 293 individuals of 12 species of 4 families were collected in Jojong Stream, and 361 individuals of 11 species of 4 families were collected in Sudong Stream. All three streams were dominated by Z. koreanus and Z. platypus. Six Korean endemic species appeared in each of the three streams, showing the high occurrence rate of indigenous species of 50.0% or more. The aggregation index analysis revealed that the mean dominance index ranged from 0.63 (${\pm}0.05$, BS) to 0.72(${\pm}0.01$, JJ), mean diversity index from 1.55 (${\pm}0.06$, JJ) to 1.78 (${\pm}0.11$, BS), mean evenness index from 0.71 (${\pm}0.03$, JJ) to 0.76 (${\pm}0.02$, BS), and mean richness index from 1.61 (${\pm}0.33$, JJ) to 1.73 (${\pm}0.24$, SD). The result indicated that the observed differences between the stream community indices were statistically nonsignificant. The similarity analysis showed that 75.4% similarity was divided into two groups of A and B and that the fish fauna on each analyzed point was similar. The quantitative habitat evaluation index (QHEI) analysis showed that the average value of QHEI was 151.0 (${\pm}46.0$), which means that it was a suboptimal habitat environment. The result of length-weight analysis of Z. koreanus populations showed that the regression coefficient b of the restoration population and the original habitat population were at 3.0 or higher while the condition factor had a positive slope. Moreover, it was found that the slopes of the regression coefficient b and condition factor of the original habitat population were larger than the restored population. The analysis of the length frequency distribution of the Z. koreanus population revealed that all three streams maintained the stable life cycle although it was found that the growth rate of the original habitat population was faster than the restored population in the one-year-old class. The result of the gonadosomatic index (GSI) analysis showed that the GSI median value of the Z. koreanus population in the restored habitat Bongseonsa Stream was higher than the population in the original habitat Jojong Stream and Sudong Stream for both of males and females.

Identification of Employee Experience Factors and Their Influence on Job Satisfaction (직원경험 요인 파악 및 직무 만족도에 끼치는 영향력 분석)

  • Juhyeon Lee;So-Hyun Lee;Hee-Woong Kim
    • Information Systems Review
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    • v.25 no.2
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    • pp.181-203
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    • 2023
  • With the fierce competition of companies for the attraction of outstanding individuals, job satisfaction of employees has been of importance. In this circumstance, many companies try to invest in job satisfaction improvement by finding employees' everyday experiences and difficulties. However, due to a lack of understanding of the employee experience, their investments are not paying off. This study examined the relationship between employee experience and job satisfaction using employee reviews and company ratings from Glassdoor, one of the largest employee communities worldwide. We use text mining techniques such as K-means clustering and LDA topic-based sentiment analysis to extract key experience factors by job level, and DistilBERT sentiment analysis to measure the sentiment score of each employee experience factor. The drawn employee experience factors and each sentiment score were analyzed quantitatively, and thereby relations between each employee experience factor and job satisfaction were analyzed. As a result, this study found that there is a significant difference between the workplace experiences of managers and general employees. In addition, employee experiences that affect job satisfaction also differed between positions, such as customer relationship and autonomy, which did not affect the satisfaction of managers. This study used text mining and quantitative modeling method based on theory of work adjustment so as to find and verify main factors of employee experience, and thus expanded research literature. In addition, the results of this study are applicable to the personnel management strategy for improving employees' job satisfaction, and are expected to improve corporate productivity ultimately.

Changes of Microbial Community Associated with Construction Method and Maintenance Practise on Soil Profile in Golf Courses (지반 조성과 관리방법에 따른 골프장 토양내 미생물 군집의 변화)

  • Moon, Kyung-Hee;Kim, Ki-Dong;Joo, Young-Kyoo
    • Asian Journal of Turfgrass Science
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    • v.23 no.2
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    • pp.219-228
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    • 2009
  • The construction procedures and artificial turf maintenance program on golf course definitely influence on the distortion of its environment. Soil microbial communities in soil profile were affected directly by those practises on turf areas. In Jeju island, the environmental impact assessment has been required to apply the first quality class granular activated carbon(GAC), which has a high absorbent character to agricultural chemicals, on the soil profiles of golf green system to reduce the pesticide leaching to ground water. This research was carried out to analyze the changes of microbial communities and chemical properties on soil profiles where GAC had been applied at the construction stage at two golf courses in Jeju. The changes of soil microbial population and chemical properties associated with construction methods of soil profile and agrochemical management program were analyzed by monthly at the surface and sub-soil profiles during April through October, 2007. The total numbers of bacteria and fungi, soil moisture content, soil physio-chemical properties were measured on greens and fairways of the both golf courses with different GAC treatment on the green and fairway soil profiles. The results showed that GAC had positive effects on the water holding capacity, pH and EC, however, it did not improved the holding capacity of available nutrients ${NO_3}^-,{NH_4}^+$, and phosphorus by its sorption phenomenon. In microbial count test, the total numbers of bacteria and fungi showed a great variation during sampling dates. That may directly relate to the agrochemical application, however, the ratio of total bacterial number versus total fungus number showed a constant value on a sub-soil of 15~30cm depth. Thus, the construction method of GAC in soil profile, and application of fertilizer and pesticide, both impacted on the changes of microbial population. It's means that the construction method of soil profile and turf management using agro-materials might greatly affect on the turfgrass culture and the environment of golf course.

A Study of the Butterfly Community of Mt. Gyeryong National Park, Korea (계룡산국립공원의 나비류 군집에 관한 연구)

  • Jeon, Sung-Jae;Cho, Young-Ho;Han, Yong-Gu;Kim, Young-Jin;Choi, Min-Joo;Park, Young-Jun;Nam, Sang-Ho
    • Korean Journal of Environment and Ecology
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    • v.26 no.3
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    • pp.348-361
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    • 2012
  • Altitude is a factor that plays an important role in the diversity, richness and composition of species. Recently, much attention has been paid to the distribution of butterflies and insects according to altitude. The purpose of this article is to propose a method to preserve and manage species efficiently by reviewing the distribution of butterflies according to different altitudes in Mt. Gyeryong National Park. This study found that the number of species and individuals decreased as the altitude increased, possibly due to the increased amount of shade caused by the crown density. When analyzing the factors influencing the distribution of species other than altitude, it was found that the slope, vegetative colonies and hydrosphere distance were correlated with the change in species distribution. As these species are closely related to food plants, it may save time and reduce the cost as well as allow an efficient evaluation of the bio-diversity if these species are selected as biological indicator species suitable for detecting the changes in the forest. It is judged to be a more efficient means of species preservation to accumulate and quantify the materials regarding environmental elements such as the climate, microclimate and food plants, as this would allow the butterfly distribution to be estimated.

A Study on Price Volatility and Properties of Time-series for the Tangerine Price in Jeju (제주지역 감귤가격의 시계열적 특성 및 가격변동성에 관한 연구)

  • Ko, Bong-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.212-217
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    • 2020
  • The purpose of this study was to analyze the volatility and properties of a time series for tangerine prices in Jeju using the GARCH model of Bollerslev(1986). First, it was found that the time series for the rate of change in tangerine prices had a thicker tail rather than a normal distribution. At a significance level of 1%, the Jarque-Bera statistic led to a rejection of the null hypothesis that the distribution of the time series for the rate of change in tangerine prices is normally distributed. Second, the correlation between the time series was high based on the Ljung-Box Q statistic, which was statistically verified through the ARCH-LM test. Third, the results of the GARCH(1,1) model estimation showed statistically significant results at a significance level of 1%, except for the constant of the mean equation. The persistence parameter value of the variance equation was estimated to be close to 1, which means that there is a high possibility that a similar level of volatility will be present in the future. Finally, it is expected that the results of this study can be used as basic data to optimize the government's tangerine supply and demand control policy.

Mixed-effects zero-inflated Poisson regression for analyzing the spread of COVID-19 in Daejeon (혼합효과 영과잉 포아송 회귀모형을 이용한 대전광역시 코로나 발생 동향 분석)

  • Kim, Gwanghee;Lee, Eunjee
    • The Korean Journal of Applied Statistics
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    • v.34 no.3
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    • pp.375-388
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    • 2021
  • This paper aims to help prevent the spread of COVID-19 by analyzing confirmed cases of COVID-19 in Daejeon. A high volume of visitors, downtown areas, and psychological fatigue with prolonged social distancing were considered as risk factors associated with the spread of COVID-19. We considered the weekly confirmed cases in each administrative district as a response variable. Explanatory variables were the number of passengers getting off at a bus station in each administrative district and the elapsed time since the Korean government had imposed distancing in daily life. We employed a mixed-effects zero-inflated Poisson regression model because the number of cases was repeatedly measured with excess zero-count data. We conducted k-means clustering to identify three groups of administrative districts having different characteristics in terms of the number of bars, the population size, and the distance to the closest college. Considering that the number of confirmed cases might vary depending on districts' characteristics, the clustering information was incorporated as a categorical explanatory variable. We found that Covid-19 was more prevalent as population size increased and a district is downtown. As the number of passengers getting off at a downtown district increased, the confirmed cases significantly increased.

Term Mapping Methodology between Everyday Words and Legal Terms for Law Information Search System (법령정보 검색을 위한 생활용어와 법률용어 간의 대응관계 탐색 방법론)

  • Kim, Ji Hyun;Lee, Jong-Seo;Lee, Myungjin;Kim, Wooju;Hong, June Seok
    • Journal of Intelligence and Information Systems
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    • v.18 no.3
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    • pp.137-152
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    • 2012
  • In the generation of Web 2.0, as many users start to make lots of web contents called user created contents by themselves, the World Wide Web is overflowing by countless information. Therefore, it becomes the key to find out meaningful information among lots of resources. Nowadays, the information retrieval is the most important thing throughout the whole field and several types of search services are developed and widely used in various fields to retrieve information that user really wants. Especially, the legal information search is one of the indispensable services in order to provide people with their convenience through searching the law necessary to their present situation as a channel getting knowledge about it. The Office of Legislation in Korea provides the Korean Law Information portal service to search the law information such as legislation, administrative rule, and judicial precedent from 2009, so people can conveniently find information related to the law. However, this service has limitation because the recent technology for search engine basically returns documents depending on whether the query is included in it or not as a search result. Therefore, it is really difficult to retrieve information related the law for general users who are not familiar with legal terms in the search engine using simple matching of keywords in spite of those kinds of efforts of the Office of Legislation in Korea, because there is a huge divergence between everyday words and legal terms which are especially from Chinese words. Generally, people try to access the law information using everyday words, so they have a difficulty to get the result that they exactly want. In this paper, we propose a term mapping methodology between everyday words and legal terms for general users who don't have sufficient background about legal terms, and we develop a search service that can provide the search results of law information from everyday words. This will be able to search the law information accurately without the knowledge of legal terminology. In other words, our research goal is to make a law information search system that general users are able to retrieval the law information with everyday words. First, this paper takes advantage of tags of internet blogs using the concept for collective intelligence to find out the term mapping relationship between everyday words and legal terms. In order to achieve our goal, we collect tags related to an everyday word from web blog posts. Generally, people add a non-hierarchical keyword or term like a synonym, especially called tag, in order to describe, classify, and manage their posts when they make any post in the internet blog. Second, the collected tags are clustered through the cluster analysis method, K-means. Then, we find a mapping relationship between an everyday word and a legal term using our estimation measure to select the fittest one that can match with an everyday word. Selected legal terms are given the definite relationship, and the relations between everyday words and legal terms are described using SKOS that is an ontology to describe the knowledge related to thesauri, classification schemes, taxonomies, and subject-heading. Thus, based on proposed mapping and searching methodologies, our legal information search system finds out a legal term mapped with user query and retrieves law information using a matched legal term, if users try to retrieve law information using an everyday word. Therefore, from our research, users can get exact results even if they do not have the knowledge related to legal terms. As a result of our research, we expect that general users who don't have professional legal background can conveniently and efficiently retrieve the legal information using everyday words.