• Journal of Energy Engineering
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• v.23 no.4
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• pp.88-94
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• 2014

In this paper, Thermal Shock tests were performed varying the composition of the solder and ribbon thickness (A-type:0.2mm/60Sn40Pb, B-type:0.25mm/60Sn40Pb, C-type:0.2 /62Sn36Ag2Pb, D-type:0.25mm/62Sn36Ag2Pb) for evaluating the long-term reliability about Ribbon junction of Silicon solar cells. Thermal Shock test condition was performed during the 600cycles having $-40^{\circ}C{\sim}85^{\circ}C$ temperature range each 15 minutes; One cycle time was 30min. As a result, the initial efficiency of the A-type, B-type, and C, D-type were showed 15.0%, 15.4% and 15.8% respectively. After thermal shock test, the efficiency decreasing-rate of each type were as follow that A-type was 13.8%, B-Type was 15.4%. C-Type and D-Type was 15.3% and 16.2%, respectively. Also, degradation of surface changes and I-V characteristic curves were showed that the series resistance of the A, C-type was increased. Also, current lowering starting point of C-type shown 0.05volt[v] earlier than that of A-type. And B, D-type shown characteristics of composite lowering efficiency such as increase of series resistance, decrease of parallel resistance and cell damage. Therefore Initial solderability and efficiency of specimens using the solder with SnAgPb were superior. But, It has inferior the long-term reliability. The test was confirmed that as the ribbon thickness increases, long-term reliability of solar cell will decrease.

• Tuberculosis and Respiratory Diseases
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• v.41 no.2
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• pp.144-151
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• 1994

Background: Miliary tuberculosis almost always results from the discharge of infected caseous material into the blood stream, usually from a well hidden lymph node in the presentation of this disease in the past four decades, and although it is seen less frequent1y today than previously, its presentation and manifestation may require greater suspicion and diligence by the physician. We investigated the clinical characteristics, predisposing factors and accompanying diseases of miliary tuberculosis and tried to acquire the early diagnosis and treatment of this disease. Methods: A retrospective clinical study was done on 40 cases of miliary tuberculosis admitted to Hanyang University Hospital from Mar. 1989 to Dec.1992. The study investigated age and sex distribution, seasonal distribution, duration of symptoms before admission, pre-disposing factors, clinical symptoms, biochemical findings, chest X-ray findings, extrapulmonary tuberculosis associated with miliary tuberculosis, prognosis and mortality rate. Results: 1) The patients were most common in the age group between 20 and 29(23%) and the ratio of male to female was 1.4:1(male 23 : female 17). 2) Sputum smears for tubercle bacilli were positive in 5 cases(13%). 3) The most common clinical symptoms were fever with chilling(47.5%), coughing(47.5%), second most common symptom was dyspnea(32.5%), and the physical findings on admission were tachycardia(30%), weight loss(27.5%), meningeal signs(17.5%) in order. 4) The predisposing factors were heavy alcohol drinking(6 cases), steroid use(3 cases), pregnancy(2 cases) etc. 5) The chest X-ray findings on admission were miliary shadow only(40%), in addition pneumonic infiltration, pleurisy, and calcification in order. 6) The extrapulmonary tuberculosis associated with miliary tuberculosis were tuberculous meningitis(30%), bone and joint tuberculosis(17.5%), intestinal tuberculosis(15%) in order. 7) Biochemical findings were increased SGOT/SGPT(32.5%), increased alkaline phosphatase(32.5%), hypoalbuminemia(15%), hyponatremia(15%) etc. 8) About 4-6 weeks later after treatment(INH, RFP, PZA, EMB), 26 cases(65%) were improved on clinical symptoms or chest X-ray, 12 cases(30%) were stationary or aggravated, and 2 cases(5%) were died. Conclusion: For the early diagnosis and treatment of miliary tuberculosis, we must see its presentation and manifestation with greater interest and suspicion and investigate its predisposing factors and accompanying diseases.

• The Korean Journal of Quaternary Research
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• v.7 no.1
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• pp.27-39
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• 1993

The shingle beach as a typical pocket beach located in Jeongdo-ri, Wando, Cheolanam-do, Korea has been investigated in terms of textural characteristics, mainly gravel shape and roundness. In the Jeongdo-ri gravel beach, changes of beach profile after storm weather and textural parameters of gravels were observed and measured from May 1992 to March 1993. Beach profile is divided into two different Fair-weather zone and Storm-weather zone influenced by dynamic condition of wave energy. The former is affected by wave and tide under fair-weather condition, the latter seems to be formed under storm-weather condition. Each zone comprises a series of beach faces and berms formed by continuous sedimentary processes of swash, overwash and backwash. Storm-weather zone is subdivided into three groups having a pair of beach face and berm respectively. Mean sizes of berm gravel(45.5 mm -123.6 mm) are coarser than gravels of beach face (36.8 mm - 78.3 mm) in fair-weather zone. On the other hand, in storm-weather zone, gravels of berms (33.1 mm -82.5 mm) are finer than those of beachfaces (46.2 mm - 105.2 mm). The proportion of disc shaped gravels of berm (50.0% - 58.5 %) is higher than that of beachface (45.9 % - 51.3 %) in each subzone except C-group of storm-weather zone. And the proportion of the equant shaped gravel increases about up to 10% seaward. Therefore, shore-normal distribution of gravels seems to be affected by shape and size sorting effects. Shore-parallel distribution pattern of gravel shape is more distinctive than size distribution patterns. That is, disc and blade shaped particles decrease up to 20% and 13% respectively, and equants increase up to 34% to the westward. Gravels plotted on Sneed and Folk's triangular diagram are more compacted and elongated with decreasing size. Therefore primary gravels are shaped by characteristics of country rock e.g. cleavage, joint etc., and secondary are affected by sorting and size-controlled process evolution by wave action.

• Journal of Technology Innovation
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• v.29 no.3
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• pp.1-31
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• 2021

With the growing importance of technology innovation as a key factor for firms' competitive advantage, 'innovation persistence' became also an important research subject. 'Innovation Persistence' is a concept that indicates whether or not firms' innovation activity or performance continues. However, the data used for innovation studies are carried out as cross-sectional surveys in most countries. For this reason, studies dealing with longitudinal aspect of innovation persistence are rare. In particular, there is almost no research on innovation persistence using Korean innovation survey data. This study reviews the concepts and characteristics of innovation persistence based on extant literature, and perform an empirical analysis on the status and features of Korean firms' technology innovation persistence. Based on the data of the Korean Innovation Survey (KIS) conducted every other year from 2012 to 2018, panel data on 3,379 firms which observed multiple times are constructed. As a result, only part of the firms with persistent innovation were observed (for innovation performance 10~12%, for innovation activity 15~17%), and it was found that the persistence of non-innovation was remarkable(about 52~57%). And it was confirmed that the persistence of innovation activities is stronger than that of innovation performance. Besides, some features by sub-types of innovation appeared. Product innovation showed higher persistence than process innovation, and internal R&D also showed higher persistence than joint/external R&D. As a result of additional logit analysis to identify factors, it was found that radical or gradual product innovation is the most influential factor in persisting innovation in the next period. Since the sample selection bias due to a limitations of raw data might exist in the panel data constructed in this study, it should be noted that faulty generalization of the results are not allowed. Nevertheless, this is the first study to examine the technology innovation persistence targeting Korean firms and is expected to be a starting point for follow-up studies. It is anticipated that advanced research results will be drawn through the establishment of official panel data and improved methodologies.

• Korean Journal of Heritage: History & Science
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• v.34
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• pp.20-58
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• 2001

In order to unravel the characteristics of arms used in the 'Three Kingdoms,' Kokuryo, Silla and Paikje. the classification and the developing procedures of the arms should be first discussed. At first, the basic arms of the soldiers of Three Kingdoms were iron swords, iron spearheads, and bows. During that period, swords attached a ring pommel were commonly used. But after 5A. D. a sword with a decoration pommel appeared. Infantry generally used iron spearheads. From the late 4A. D. the long spearheads were broadly used in cavalry battles. In the late 6A. D. infantry mainly used long spearheads, and this resulted in the foundation of long spearheads units. There were two kinds of bows: Short Bow whose arch is small and Long Bow whose arch is long. It is known that the Short Bow was widely used in Kokuryo and Paikje up to 5A. D. In the early era, infantry used Long Bow, yet it was vastly used after 6A. D. when a castle's strategical value was great and defending a castle was. significant. Above mentioned, as basic combat weapons, iron spearhead and bow were fundamental. In particular, the spearhead was the essential weapon to a soldier. Yet, arrow gun and hook-shape cutters were important weapons. Especially, after 6A.D., when a castle became strategically pivotal in military, the arrow gun became the important weapon. This resulted in the foundation of arrow gun units. Hook-shape cutters were used to snatch horsemen or to climb up to fall the castle. Yet, the cutter was not the Three Kingodoms' basic weapon. In addition, the three stages of arms development in the Three Kingdoms are formation stage, development stage, and settlement stage. The formation stage was the period when premitive military unit appeared in the Three Kingdoms. It ranged from 1B. C. to the mid 3A. D. At that time according to regions. there were two weapon systems operating: North area including Kokuryo and the northern part of Paikje and South area including Silla, Kaya and the southern part of Paikje. ln North area a sword with a ring attached at the end of the holder, iron spear with neck and mid-size flat holder and iron arrowhead with an extension to fix, were used. In this period, during a war calvary units were mostly used and their weapon systems seemed possibly to succeed in that of Kochosun. In the development stage, when LoLang's influence on surroundings became weak, Koguryo, Paikjae and Silla had directly contacted each other. In the late 3A.D. to the early 6A.D., Silla achieved a drastic improvement in weapon system. This was the period when Kokuryo played a leading role in arms race. Kokuryo's arms manufacturing techniques passed onto Silla, Kaya and Paikje. In combat strategy a joint operation between infantry and calvary prevailed even if their military tactics were different. In a calvary battle heavily armed horsemen played import roles at this period. The horsemen and even horses were heavily guarded with iron armors. After all, the appearance of fully armed horsemen implies the very need of powerful destructive forces in weapon system. At that time, basic weapons were a big sword with a ring attached at the end of the holder, swallow's tail-shape spear with neck, and iron spearhead with neck and an extension. The settlement stage began at the mid 6A.D., when it was the revolutionary period in the arms development history. Of course, actual proofs and picture documents were not sufficient enough to penetrate full scale of the weapon system. But, according to historical circumstances and historic records, it is very certain that this period was the peak in arms development. In this period special military units, such as infantry-calvary companies, Archery units and Long spear units, that executed particular duties with special weapons, were founded. This became the characteristics of the settlement stage.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.257-265
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• 2023

The purpose of this study was to vaccinate every year according to the general characteristics of COVID-19, whether to vaccinate every year according to the vaccination experience, whether to vaccinate every year according to knowledge/attitude about vaccination, and negative responses to the vaccinate every year In order to understand the factors affecting the vaccination physician every year by identifying the factors of Statistical analysis is based on general characteristics, variables based on vaccination experience, and knowledge/attitudes related to vaccination. The doctor calculates the frequency and percentage, A square test (-test) was performed, and if the chi-square test was significant but the expected frequency was less than 5 for 25% or more, a ratio difference test was performed with Fisher's exact test. Through multiple logistic regression analysis using variables that were significant in simple analysis, a predictive model for future vaccination and the effect size of each independent variable were estimated. As statistical analysis software, SAS 9.4 (SAS Institute Inc., Cary, NC, USA) was used, and because the sample size was not large, the significance level was set at 10%, and when the p-value was less than 0.10, it was interpreted as statistically significant. In the simple logistic regression analysis, the reason why they answered that they would not be vaccinated every year was that they answered 'to prevent infection of family and hospital guests' rather than 'to prevent my infection' as the reason for the vaccination. It was 11.0 times higher and 3.67 times higher in the case of 'for the formation of collective immunity of the local community and the country'. The adverse reactions experienced after the 1st and 2nd vaccination were 8.42 times higher in those who did not experience pain at the injection site than those who did not, 4.00 times higher in those who experienced swelling or redness, and 5.69 times higher in those who experienced joint pain. There was a 5.57 times higher rate of absenteeism annually than those who did not. In addition, the more anxious they felt about vaccination, the more likely they were to not get the vaccine every year by 2.94 times.

• Journal of Oral Medicine and Pain
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• v.36 no.1
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• pp.39-51
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• 2011

The aims of this study were to investigate whether the facial skeletal patterns previously reported to be related to temporomandibular disorder (TMD) in other studies could be consistently observed in the TMD patients diagnosed according to Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) Axis I and evaluate its usability in the orthodontic clinics to examine the patients with TMD related symptoms. The clinical records and radiographs of female patients who visited the TMD and Orofacial Pain Clinic of Seoul National University Dental Hospital and were diagnosed as TMD were consecutively filed for this study. Patients were clinically examined and diagnosed according to the revised diagnostic algorithms of RDC/TMD Axis I and the lateral cephalogram, panoramic orthopantomogram, temporomandibular joint (TMJ) orthopantomogram, and transcranial radiograph of each patient were taken and digitalized. The data of patients who were under 18 years of age or had any systemic disease, trauma history involving the TMJ, or skeletal deformity at the time of the first examination were excluded. The remaining data of 96 female patients were finally analyzed. The obtained results were as follows: 1. There are no significant differences of cephalometric measurements between RDC I (muscle disorders) diagnostic groups. 2. Only the articular angle of the RDC group IIc (disk displacement without reduction without limited opening) patients was larger than patients of the no diagnosis of RDC II group (disk displacement). 3. Larger articular angle and smaller facial height ratio were observed in RDC IIIc group (osteoarthrosis) compared to IIIa group (arthralgia). Larger articular angle, larger Bjork sum, smaller posterior facial height, and smaller facial height ratio were observed in RDC group IIIc compared to no diagnosis of RDC III group (arthralgia, arthritis, and arthrosis). 4. According to the results of cephalometric analysis in simplified RDC groups, smaller overjet was observed in muscle disorders (MD) group. Facial height ratio and IMPA were smaller and articular angle was larger in disk displacements (DD) group than in no diagnosis of DD group. In arthrosis (AR) group, posterior facial height, and facial height ratio were smaller, and articular angle, gonial angle, facial convexity, FMA, Bjork sum, and ANB were larger than in no diagnosis of AR group. In joint pain (JP) group, only posterior facial height was smaller than no diagnosis of JP group. In conclusion, Facial morphologic patterns showing posterior-rotated mandible and lower posterior facial height is related to RDC group II and III diagnosis of the TMJ in female TMD patients. RDC/TMD Axis I diagnosis can provide a good clinical diagnostic tool for the standardized examination of the TMJ in orthodontic clinics.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.172-187
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• 2019

Knowledge of intangible cultural heritage is usually disseminated through word-of-mouth and actions rather than written records. Thus, people assemble to teach others about it and form communities. Accordingly, to understand and spread information about intangible cultural heritage properly, it is necessary to understand not only their attributes but also a community's relational characteristics. Community members include specialized transmitters who work under the auspices of institutions, and general transmitters who enjoy intangible cultural heritage in their daily lives. They converse about intangible cultural heritage in close relationships. However, to date, research has focused only on professionals. Thus, this study focused on the roles of general transmitters of intangible cultural heritage information by investigating intangible cultural heritage communities centering around Jeongseon Arirang; a social network analysis was performed. Regarding the research objectives presented in the introduction, the main findings of the study are summarized as follows. First, there were 197 links between 74 members of the Jeongseon Arirang Transmission Community. One individual had connections with 2.7 persons on average, and all were connected through two steps in the community. However, the density and the clustering coefficient were low, 0.036 and 0.32, respectively; therefore, the cohesiveness of this community was low, and the relationships between the members were not strong. Second, 'Young-ran Yu', 'Nam-gi Kim' and 'Gil-ja Kim' were found to be the prominent figures of the Jeongseon Arirang Transmission Community, and the central structure of the network was concentrated around these three individuals. Being located in the central structure of the network indicates that a person is popular and ranked high. Also, it means that a person has an advantage in terms of the speed and quantity of the acquisition of information and resources, and is in a relatively superior position in terms of bargaining power. Third, to understand the replaceability of the roles of Young-ran Yu, Nam-gi Kim, and Gil-ja Kim, who were found to be the major figures through an analysis of the central structure, structural equivalence was profiled. The results of the analysis showed that the positions and roles of Young-ran Yu, Nam-gi Kim, and Gil-ja Kim were unrivaled and irreplaceable in the Jeongseon Arirang Transmission Community. However, considering that these three members were in their 60s and 70s, it seemed that it would be necessary to prepare measures for the smooth maintenance and operation of the community. Fourth, to examine the subgroup hidden in the network of the Jeongseon Arirang Transmission Community, an analysis of communities was conducted. A community refers to a subgroup clearly differentiated based on modularity. The results of the analysis identified the existence of four communities. Furthermore, the results of an analysis of the central structure showed that the communities were formed and centered around Young-ran Yu, Hyung-jo Kim, Nam-gi Kim, and Gil-ja Kim. Most of the transmission TAs recommended by those members, students who completed a course, transmission scholarship holders, and the general members taught in the transmission classes of the Jeongseon Arirang Preservation Society were included as members of the communities. Through these findings, it was discovered that it is possible to maintain the transmission genealogy, making an exchange with the general members by employing the present method for the transmission of Jeongseon Arirang, the joint transmission method. It is worth paying attention to the joint transmission method as it overcomes the demerits of the existing closed one-on-one apprentice method and provides members with an opportunity to learn their masters' various singing styles. This study is significant for the following reasons: First, by collecting and examining data using a social network analysis method, this study analyzed phenomena that had been difficult to investigate using existing statistical analyses. Second, by adopting a different approach to the previous method in which the genealogy was understood, looking at oral data, this study analyzed the structures of the transmitters' relationships with objective and quantitative data. Third, this study visualized and presented the abstract structures of the relationships among the transmitters of intangible cultural heritage information on a 2D spring map. The results of this study can be utilized as a baseline for the development of community-centered policies for the protection of intangible cultural heritage specified in the UNESCO Convention for the Safeguarding of Intangible Cultural Heritage. To achieve this, it would be necessary to supplement this study through case studies and follow-up studies on more aspects in the future.

• Journal of agricultural medicine and community health
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• v.25 no.1
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• pp.65-83
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• 2000

To know the relationship of general characteristics with activities of daily living(ADL) and instrumental activities of daily living(IADL), we carried out the study on the elderies living in Chollabuk-Do area during 6 months, from June to December in 1999. Study subjects were 281, women and men were 195(69.6%) and 85(30.4%) respectively. Mean ages of women and men were 71.9 and 70.8 respectively. 81.1% elderies has disease and 18.9% were disease free. Disease prevalences of movement joint disease, others, circulatory disease, digestive disease, dental disease, respiratory disease were 50.1%, 25.0%, 10.5%, 9.4%, 8.5%, and 6.3% respectively. The percentages to the use of medical institution in recent were 40.0% for hospital, 16.8% for oriental hospital, 14.5% for public health center, 10.9% for drug store, 10.0% for others, and 7.8% for dental service. The percentages to the improvement of symptom after the use of medical institution were 62.3% for normal, 19.4% for improvement, and 18.2% for non-improvement. The percentages to the health situation were 37.1% for bad, 35.7% for good, and 27.1% for normal. Activities of daily living were 67.1% for 6 scores, 27.9% for 5 scores, 2.1% for 4 scores and ADL of women was lower than the men's. Instrumental activities of daily living were 50.4% for 5 scores, 19.3% for 3 scores, 12.1% for 4 scores and IADL of women was lower than the men's. Frequencies of disability in ADL were 28.9% for incontinence, 6.1% for bathing, 2.9% for meal, 2.5% for walking around house, 1.8% for toilet use, 1.4% for dressing and disability frequencies of women in 6 items of ADL were higher than the men's. The percentages of high, intermediate, low ADL in activities of daily living were 67.1%, 32.5%, 0.4% respectively and decrease of high ADL, increase of intermediate ADL were found with the increasing of age. Frequencies of disability in IADL were 42.9% for payment in and out, 31.8% for payment of written claim, 21.1% for shopping, 16.4% for preparation of meal, and 11.8% for use of bus. All items of women in IADL was higher than the men's but preparation of meal. The percentages of high, intermediate, low IADL in instrumental activities of daily living were 50.4%, 42.5%, 7.1% and decrease of high IADL, increase of intermediate IADL were found with the increasing of age. Mean of ADL with the general characteristics was 5.56 and 2 variables of level of education, health situation were statistically significant. Mean of IADL with the general characteristics was 3.76 and 8 variables of age, sex, level of education, occupation, presence of spouse, duty of living cost, health situation, category of ADL were statistically significant. With the result of stepwise regression, ADL was statistically related with religion, health situation and ADL was statistically related with level of education, living together with family, duty of living cost, health situation.

• Journal of Korean Society for Geospatial Information Science
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• v.22 no.4
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• pp.21-30
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• 2014

Lately, new influentials have secured a large number of volunteers on social networks due to vitalization of various social media. There has been considerable research on these influential people in social networks but the research has limitations on location information of Location Based Social Network Service(LBSNS). Therefore, the purpose of this study is to propose a spatial detection methodology and application plan for influentials who make comments about diverse social and cultural issues in LBSNS using spatial statistical analysis methods. Twitter was used to collect analysis object data and 168,040 Twitter messages were collected in Seoul over a month-long period. In addition, 'politics,' 'economy,' and 'IT' were set as categories and hot issue keywords as given categories. Therefore, it was possible to come up with an exposure index for searching influentials in respect to hot issue keywords, and exposure index by administrative units of Seoul was calculated through a spatial joint operation. Moreover, an influential index that considers the spatial dependence of the exposure index was drawn to extract information on the influential areas at the top 5% of the influential index and analyze the spatial distribution characteristics and spatial correlation. The experimental results demonstrated that spatial correlation coefficient was relatively high at more than 0.3 in same categories, and correlation coefficient between politics category and economy category was also more than 0.3. On the other hand, correlation coefficient between politics category and IT category was very low at 0.18, and between economy category and IT category was also very weak at 0.15. This study has a significance for materialization of influentials from spatial information perspective, and can be usefully utilized in the field of gCRM in the future.