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Temporal and Spatial Distribution of Benthic Polychaetous Communities in Seomjin River Estuary (섬진강 하구역 저서다모류군집의 시·공간 분포)

  • Kang, Sung Hyo;Lee, Jung Ho;Park, Sung Wan;Shin, Hyun Chool
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.19 no.4
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    • pp.243-255
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    • 2014
  • This study was investigated to estimate the relations between benthic environments and benthic polychaetous community from April 2012 to February 2013. Twenty four stations were selected sequentially with Seomjin River Estuary from the northern part of Gwangyang Bay. The study area could be divided into three characteristic zones based on salinity, water temperature, dissolved oxygen and pH such as Saline Water Zone (SWZ), Brackish Water Zone (BWZ), and Fresh Water Zone (FWZ). Salinity was above 30.0 psu in SWZ, drastically decreased toward inland in BWZ, and nearly zero psu in FWZ. SWZ showed its specific environmental characters like that water temperature fluctuated with little seasonal change and DO showed the lowest values among three zones, and pH maintained as consistent value without seasonal fluctuation. In FWZ, on the other hand, water temperature showed high seasonal fluctuation, DO showed the highest values among three zones, and pH fluctuated greatly. In sedimentary environment, mud, sand and sand/gravel were found as dominant sedimentary deposits in SWZ, BWZ and FWZ, respectively. Organic matter content and AVS in surface sediment were high in SWZ, while Chl-a content high in FWZ. This study area showed a marked environmental difference between FWZ and SWZ as follows: FWZ has coarse sediment and low salinity, low organic matter content, low AVS in FWZ but SWZ has fine sediment and high salinity, high organic matter content and AVS. Species number and mean density of benthic polychaete community was highest in Saline Water Zone (SWZ), drastically decreased in Brackish Water Zone (BWZ), and lowest in Fresh Water Zone (FWZ). Dominant polychates above 5.0% of individual numbers were 6 taxa. Lumbrineris longifolia, Prionospio cirrifera, Tharyx sp. occurred as main dominant species of all study periods, and Hediste sp., Praxillella affinis, Tylorrhynchus sp. dominantly occurred at some seasons. Inhabiting areas of dominant species were separated characteristically. Representative species in SWZ were Lumbrineris longifolia, Tharyx sp., Mediomastus sp.. Wide-appearing species between SWZ and BWZ were Prionospio cirrifera, Heteromastus filiformis, Aricidea sp.. Characteristic species in FWZ were Tylorrhynchus sp. and Hediste sp.. As the results of cluster analysis and nMDS based on the species composition of polychaetous community, unique station groups were established in SWZ and FWZ. Stations in BWZ were sub-divided into several groups with season. Pearson's correlation analysis and PCA between benthic environments and ecological characteristics of polychaetous community showed that salinity, sediment composition, organic content and dissolved oxygen played a role to determine the temporal and spatial distribution of the ecological characteristics as species number, mean density, abundance of main species, and ecological indices.

Comparison of Serum Cytokines($IL-1{\beta}$, IL-6, and $TNF-{\alpha}$) between Terminal Cancer Patients Treated with Vitamin C and Them without Vitamin C Therapy (Anorexia-Cachexia Syndrome을 가진 말기 암 환자에서 비타민 C 사용여부에 따른 사이토카인 변화 비교)

  • Yeom, Chang-Hwan;Suh, Sang-Youn;Cho, Kyung-Hee;Sun, Young-Gyu;Park, Yong-Gyu;Lee, Hye-Ree
    • Journal of Hospice and Palliative Care
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    • v.6 no.1
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    • pp.51-57
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    • 2003
  • Purpose : Anorexia-cachexia syndrome is one of the most common symptoms and main cause of death in terminal cancer patients. This symptom is due to the enlarged cancer mass as well as tumor released cytokines. Some doctors have suggested that vitamin C was preferentially toxic to tumor cells in vitro and in vivo, and improved clinical symptoms in terminal cancer patients. Therefore, we measured cytokines in serum of terminal cancer patients to determine whether vitamin C treatment improved the anorexia-cachexia syndrome. Methods : We investigated that 49 terminal cancer patients admitted to the department of family medicine, National Health Insurance Corporation Ilsan hospital from March 1, 2002 to August 31, 2002. The study was done on 22 patients who were given 10 g/day of vitamin C infusions during 1 week and 27 patients who were not infused. We measured the cytokines levels ($IL-1{\beta}$, IL-6, and $TNF-{\alpha}$) before and after 1 week between terminal cancer patients treated vitamin C and without vitamin C. Results : Out of 49 patients, patents treated with vitamin C infusions were 22 (12 male, 10 female), and these without vitamin C were 27 (18 male, 9 female). In patients treated with vitamin C, $IL-1{\beta}\;were\;6.19{\pm}5.17$ before day and $8.76{\pm}5.72$ after 1 week, IL-6 were $3.07{\pm}8.09$ before day and $1.31{\pm}2.36$ after 1 week, and $TNF-{\alpha}\;were\;2.74{\pm}14.24$ before day and $0.50{\pm}2.00$ after 1 week. In patients treated without vitamin C, $IL-1{\beta}\;were\;2.50{\pm}3.58$ before day and $6.49{\pm}12.01$ after 1 week, IL-6 were $1.00{\pm}2.19$ before day and $17.16{\pm}81.55$ after 1 week, and $TNF-{\alpha}\;were\;1.19{\pm}2.98$ before day and $1.27{\pm}1.52$ after 1 week. The level of cytokines in patients treated with vitamin C decreased more than those without vitamin C. However, this represented no statistical value (P=0.0598 in $IL-1{\beta}$, P=0.1664 in IL-6, and P=0.5395 in $TNF-{\alpha}$). Conclusion : In terminal cancer, even if there was no statistical difference in the cytokines levels between patients treated with vitamin C and those not treated, those who were treated had a decrease all cytokines levels. Vitamin C is very safe with almost no side effects. Therefore, vitamin C treatment in terminal cancer patients can be seen as beneficial and helpful for clinical symptoms.

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An Exploratory study on the demand for training programs to improve Real Estate Agents job performance -Focused on Cheonan, Chungnam- (부동산중개인의 직무능력 향상을 위한 교육프로그램 욕구에 관한 탐색적 연구 -충청남도 천안지역을 중심으로-)

  • Lee, Jae-Beom
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.9
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    • pp.3856-3868
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    • 2011
  • Until recently, research trend in real estate has been focused on real estate market and the market analysis. But the studies on real estate training program development for real estate agents to improve their job performance are relatively short in numbers. Thus, this study shows empirical analysis of the needs for the training programs for real estate agents in Cheonan to improve their job performance. The results are as follows. First, in the survey of asking what educational contents they need in order to improve real estate agents' job performance, most of the respondents show their needs for the analysis of house's value, legal knowledge, real estate management, accounting, real estate marketing, and understanding of the real estate policy. This is because they are well aware that the best way of responding to the changing clients' needs comes from training programs. Secondly, asked about real estate marketing strategies, most of respondents showed their awareness of new strategies to meet the needs of clients. This is because new forms of marketing strategies including internet ads are needed in the field as the paradigm including Information Technology changes. Thirdly, asked about the need for real estate-related training programs, 92% of the respondents answered they need real estate education programs run by the continuing education centers of the universities. In addition, the survey showed their needs for retraining programs that utilize the resources in the local universities. Other than this, to have effective and efficient training programs, they demanded running a training system by utilizing the human resources of the universities under the name of the department of 'Real Estate Contract' for real estate agents' job performance. Fourthly, the survey revealed real estate management(44.2%) and real estate marketing(42.3%) is the most chosen contents they want to take in the regular course for improving real estate agents' job performance. This shows their will to understand clients' needs through the mind of real estate management and real estate marketing. The survey showed they prefer the training programs as an irregular course to those in the regular one. Despite the above results, this study chose subjects only in Cheanan and thus it needs to research more diverse areas. The needs of programs to improve real estate agents job performance should be analyzed empirically targeting the real estate agents not just in Cheonan but also cities like Pyeongchon, Ilsan and Bundang in which real estate business is booming, as well as undergraduate and graduate students whose major is real estate studies. These studies will be able to provide information to help develop the customized training programs by evaluating elements that real estate agents need in order to meet clients satisfaction and improve their job performance. Many variables of the program development learned through these studies can be incorporated in the curriculum of the real estate studies and used very practically as information for the development of the real estate studies in this fast changing era.

Effects of Alginic Acid, Cellulose and Pectin Level on Bowel Function in Rats (알긴산과 셀룰로오스 및 펙틴 수준이 흰쥐의 대장기능에 미치는 영향)

  • 이형자
    • Journal of Nutrition and Health
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    • v.30 no.5
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    • pp.465-477
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    • 1997
  • The purpose of this article is to know the effects on bowel function of the kind of fiber and the amount of fiber in SD-rats. To do this experiment, we select of $\alpha$-cellulose as n insoluble cellulose source and alginic acid and pectin as soluble cellulose source. The rats diets contained callolose camcentrations of 1.0%, 3.6%, 6.0% and 10.0%. After that, we raised the SD-rats for 4weeks and measured the amount of food intake, body weight, the food effciency ratio, the length of liver and stomach the weight of the intestines, the transit time through the intestines, pH in feces, and the amount of bile acid and Ca, Mg, pp. 1) The amount of food intake was 15.75-31.00g/day. It was highest in the 10.0% cellulose group and the lowest in the 3.6% and 6.0% alginic acid group (p<0.05). The body weights of rats were 277.50-349.809. It was highest in the 1.0% pectin group and lowest in the 3.6% alginic acid group, 6.0% cellulose group, and 10.0% pectin group. It had differences according to the content fiber and the kind of dietary(p<0.01). The food efficiency ratio was (p<0.01). The higher the content of dietary fiber, the lower the calory and the food efficiency ratio. 2) Transit time was 446.0-775.0 minutes and it showed signidicant ifferences according to the content and kind of dietary fiber(p<0.01). It was long in the 1.0% cellulose group and 1.0% pectin group but short in the 10.0% alginic acid group. As the content of dietary fiber increased, the transit time through the intestines was shortened. The length of small intestine was 101.03-120.40cm and there were no difference cegardloss of the content and kind of fiber. The length of the large intestine was 20.92-25.42cm and there were significant differences according to the content and kind of the fiber. High-fiber diets resulted in increases in the length of the large intestine. 3) The weight of the liver was 8.68-10.96g and there were no differences according to the content and kind of fiber. The weight of stomach was 1.28-1.74g and there were no differences resulting from the kind of dietary fiber, but it was highest in the 10.0% alginic acid group. The weight of the small intestine was 5.52-8.04g with no difference resulting from to the kind of fiber. It was highest in the 10.0% the alginic acid group and lowest in the 1.0% alginic acid group(p<0.05). The weight of large intestine was 2.50-3.30g with no differences related to the kind of dietary fiber. It was heaviest in the 6.0% and 10.0% alginic acid groups and in the 10.0% pectin group with differences related to the content of fiber(p<0.05). 4) The pH of the feces was 5.82-6.86 according to the kind of dietary fiber, alginic acid group was high at 6.66, the cellulose group was 6.26. but the pectin group was low at 6.30. There were difference according to the content of fiber, but no consistency. The content of bile acid was 6.25-34.77umol per 1g of dry feces. According to the kind of dietary fiber, the alginic acid group was low at 12.91umol, cellulose group was 18.64umol and, the pectin group was the highest at 27.78umol(p<0.001). Based on the content of dietary fiber, alginic acid group was low at 1.0%, but high at 3.6% pectin group(p<0.001). 5) The amount of feces was 1.00-5.10g/day. The weight of rat feces was 2.23g/day in the alginic acid goup, 2.75g/day in the cellulose group, and 1.82g/day in the pectin group. According to the content of fiber, cellulose group was high at 10.0% but alginic acid group was 1.0%, and there were significant difference according to the dietary fiber. The more the content of fiber, the more increase the content of feces in alginic acid, cellulose and pectin group. The content of Ca in the feces was 80.10-207.82mg/1g of dry feces. In the dietary fiber, alginic acid group was 193.08mg, cellulose group was 87.5mg, pectin group was 138.16mg. In the content of fiber, alginic acid group was high at 1.0% and 3.6% but low at 10.0% of Pectin group. The content of Mg was 19.15-44.72mg/1g of dry feces. According to the kind of dietary fiber, alginic acid group was 35.33mg, cellulose group was 23.60mg, and pectin was 36.93mg. According to the content of fiber, pectin group was high at 1.0% and low at 10.0% of cellulose group. The content of P was 1.65-4.65mg/1g of dry feces. According to the kind of dietary fiber, alginic acid group 2.23mg/g dry feces, cellulose group was 2.29mg/g, pectin group wa 4.08mg/g dry feces. In the content of fiber, pectin group was high at 6.0% and low at 6.0% alginic acid group, but there were significant difference among the analysis value. The conetnt of Ca and MG was higher in soluble alginic acid group and pectin group than in insoluble cellulose group. The high the content of the dietary fiber, the lower the food efficiency ratio and the short the transit time through intestine with the increase of the length of large intestin as well as the higher level of the stomach, the small intestine and the large intestine. According to the content of the dietary fiber, the amount of the feces, Ca, Mg and P was increased but the length the small intestin, the weight of liver, pH of the feces and the amount of bile acid showed no differences and consistency.

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A Comparison of the Designation Characteristics of Korean Scenic Sites Policies and National Park System in the United States (국내 명승 정책과 미국 국립공원 시스템의 지정 특성 비교)

  • Lee, Won-Ho;Kim, Dong-Hyun;Janet, R. Balsom
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.38 no.3
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    • pp.25-34
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    • 2020
  • This study examined the definition and major values, the designated procedures and types, and the designation trend in Korean scenic sites and national parks in the United States. Based on this, the analysis of the characteristics of the designation of the two natural heritages. The results are as follows; First, Scenic Sites has characteristics of complex heritage that includes academic, historical, and humanities values on the basis of landscape. As a natural heritage based on public nature, the U.S. National Park aims to contribute to the people's natural heritage and satisfy both ecological and historical values through the protection of the landscape. Second, the designation of a scenic sites are decided through deliberation by the Cultural Heritage Committee after the request of the owner, manager, or local government or by the authority of the head of the Cultural Heritage Administration. The designated survey is divided into basic resource surveys and resource surveys by type. Since the initial designation of the Sogeumgang Mountain in Cheonghakdong, Myeongju in 1970, the number of designated scenic sites was low until the 2000s, but the number of designated scenic sites has increased rapidly since 2006 due to the policy to promote the scenic site, and the proportion of natural and historical and cultural scenic sites has been balanced. The designation of the U.S. national park is decided by the Congress or the president, and the National Park Service makes a series of decisions on whether to conduct a special resource study of provisional resources through a preliminary inspection survey, whether to satisfy the criteria for designation of national parks based on the results of special resource research, and to prioritize them. The U.S. National Parks have been expanded not only by Congress but also by the president's empowerment to designate them as national monuments. With the integrated operation of the National Park Service, the number of designated cases increased as the national park included the heritage sites under the control of various ministries. In addition, a number of historical areas were designated by the enactment of the Historical Site Act, and recreational areas were designated to provide leisure space and classified and managed in a total of 18 units. Third, the comparison of the designation characteristics of the two heritage properties confirmed that the designation of natural heritage with complex value, the classification of types according to complementary designation system and resource characteristics, the establishment of the competent ministry and the balancing of the heritage according to the designation policy. The two heritages had the characteristics of complex natural heritages that met ecological, historical and academic values at the same time based on landscape and public nature. In addition, both countries have identified a system for deliberating the designation of heritage through a basic resource survey and an in-depth designation survey, and classified each type according to the characteristics of the resource. In addition, the policies for promoting scenic sites in Korea and the integrated operation of the National Park Service in the U.S. influenced the designated aspects of the two heritage sites, balancing natural heritage with historical and cultural heritage. Fourth, the resource types and conservation management methods of Scenic site and National Park were largely related. The natural areas of the U.S. National Park include types of natural monuments in Korea as major resources, and have characteristics similar to natural scenic sites. In addition, historical resources were similar to the criteria for designation of historical and cultural scenic sites in terms of landscape, and the aspects of war and celebrity-related relics were related to the types of historic sites. In terms of conservation management, the natural area of the U.S. national park has a way of keeping the original ecosystem intact, but the Korean natural heritage protection system is likely to be useful for focusing on the resource of viscosity. Meanwhile, historical resources include historical sites and historical and cultural scenic sites in the traditional era, but historical relics in the U.S. National Parks have set a time limit to modern times for war history and celebrity-related relics, and the active provision of entertainment programs based on existing resources was derived as a difference.

Annual Reproductive Cycle and Changes in Plasma Levels of Sex Steroid Hormones of the Female Korean Dark Sleeper, Odontobutis platycephala (Iwata et Jeon) (동사리, Odontobutis platycephala (Iwata et Jeon) 암컷의 생식주기와 혈중 성스테로이드 호르몬의 변화)

  • LEE Won-Kyo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.31 no.4
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    • pp.599-607
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    • 1998
  • To clarify annual reproductive cycle of Korean dark sleeper, Odontobutis platycephala (Iwata et Jeon), we examined the seasonal changes of gonadosomatic index (GSI), the proportional frequency of oocyte development stages in the ovary and the changes of sex steroid hormone levels in blood from December 1995 to November 1997. In July and August, GSI was 0.35 to 0.72 and most oocytes in the ovary were chromatin-nucleolus stage and perinucleolar stage (proportional frequency: $87\%\~96\%$). In September, GSI was 1.20 $\pm$ 0.12, some oocytes in the ovary were yolk vesifle stage (proportional frequency: $22.8\%$) and vitellogenic stage which appeared very rarely(proportional frequency: $2.2\%$). GSI increased gradually from October and reached 4.59± 0.61 to December. During this period, oocytes of vitellogenic stage increased slightly (proportional frequency in December: $22.1\%$). In January, GSI was 4.32 $\pm$ 0.72 but the proportional frequency of oocytes in vitellogenic stage increased (proportional frequency: $51.2\%$). from February, GSI was increased sharply and reached to 10.51 $\pm$ 1.04 in March, the highest value throughout the year and the proportional frequency of oocytes in vitellogenic stage also reached the highest levels (proportional frequency: $60\%$). From April, GSI was gradually decreased and fell down to 1.11 $\pm$ 0.35 in June. During this period, the proportional frequency of mature oocytes was the highest in April (proportional frequency of mature oocyte stage: $40\%$ in April, $12\%$ May, $5\%$ June) throughout the year, and atretic ovarian follicles were appeared. The blood level of estradiol-17$\beta$ ($E_2$), which stimulates the hepatic synthesis and secretion of vitellogenin, was $0.84{\pm}0.20\;ng/m{\ell}$ in August, and thereafter was not changed until December. from January, it increased sharply and reached the highest level of $ 2.85{\pm}0.35\;ng/m{\ell}$ in March throughout the year, but fell to $0.14{\pm}0.02\;ng/m{\ell}$ in July(P<0.05), 17$\alpha$-hydroxprogesterone(17$\alpha$-OHP) was the peak $13.37{\pm}0.52ng/m{\ell}$ in March, but no significant changes in other period(below $3ng/m{\ell}$, P<0.05). 17$\alpha$, 20$\beta$-dihydroxy-4-pregnen-3-one(17$\alpha$, 20$\beta$-P), which was known as the final maturation inducing hormone in teleost, was $0.74{\pm}0.09ng/m{\ell}$ in April and $0.54{\pm}0.07ng/m{\ell}$ in May, but no significant changes in other period (below $0.26\;ng/m{\ell}$, p<0.05). Taken together these results, the annual reproductive cycle of O. platycephala divided into 4 periods as follows: 1) ripe and spawning period from April to June, main spawning period was from April to May, 2) Resting period from July to August, 3) Growing period from September to December, 4) Maturing period from January to March. Moreover, It was showed that the changes of sex steroid hormone in blood played a important roles in the annual reproductive cycle of O. platycephala.

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Effects of Customers' Relationship Networks on Organizational Performance: Focusing on Facebook Fan Page (고객 간 관계 네트워크가 조직성과에 미치는 영향: 페이스북 기업 팬페이지를 중심으로)

  • Jeon, Su-Hyeon;Kwahk, Kee-Young
    • Journal of Intelligence and Information Systems
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    • v.22 no.2
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    • pp.57-79
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    • 2016
  • It is a rising trend that the number of users using one of the social media channels, the Social Network Service, so called the SNS, is getting increased. As per to this social trend, more companies have interest in this networking platform and start to invest their funds in it. It has received much attention as a tool spreading and expanding the message that a company wants to deliver to its customers and has been recognized as an important channel in terms of the relationship marketing with them. The environment of media that is radically changing these days makes possible for companies to approach their customers in various ways. Particularly, the social network service, which has been developed rapidly, provides the environment that customers can freely talk about products. For companies, it also works as a channel that gives customized information to customers. To succeed in the online environment, companies need to not only build the relationship between companies and customers but focus on the relationship between customers as well. In response to the online environment with the continuous development of technology, companies have tirelessly made the novel marketing strategy. Especially, as the one-to-one marketing to customers become available, it is more important for companies to maintain the relationship marketing with their customers. Among many SNS, Facebook, which many companies use as a communication channel, provides a fan page service for each company that supports its business. Facebook fan page is the platform that the event, information and announcement can be shared with customers using texts, videos, and pictures. Companies open their own fan pages in order to inform their companies and businesses. Such page functions as the websites of companies and has a characteristic of their brand communities such as blogs as well. As Facebook has become the major communication medium with customers, companies recognize its importance as the effective marketing channel, but they still need to investigate their business performances by using Facebook. Although there are infinite potentials in Facebook fan page that even has a function as a community between users, which other platforms do not, it is incomplete to regard companies' Facebook fan pages as communities and analyze them. In this study, it explores the relationship among customers through the network of the Facebook fan page users. The previous studies on a company's Facebook fan page were focused on finding out the effective operational direction by analyzing the use state of the company. However, in this study, it draws out the structural variable of the network, which customer committment can be measured by applying the social network analysis methodology and investigates the influence of the structural characteristics of network on the business performance of companies in an empirical way. Through each company's Facebook fan page, the network of users who engaged in the communication with each company is exploited and it is the one-mode undirected binary network that respectively regards users and the relationship of them in terms of their marketing activities as the node and link. In this network, it draws out the structural variable of network that can explain the customer commitment, who pressed "like," made comments and shared the Facebook marketing message, of each company by calculating density, global clustering coefficient, mean geodesic distance, diameter. By exploiting companies' historical performance such as net income and Tobin's Q indicator as the result variables, this study investigates influence on companies' business performances. For this purpose, it collects the network data on the subjects of 54 companies among KOSPI-listed companies, which have posted more than 100 articles on their Facebook fan pages during the data collection period. Then it draws out the network indicator of each company. The indicator related to companies' performances is calculated, based on the posted value on DART website of the Financial Supervisory Service. From the academic perspective, this study suggests a new approach through the social network analysis methodology to researchers who attempt to study the business-purpose utilization of the social media channel. From the practical perspective, this study proposes the more substantive marketing performance measurements to companies performing marketing activities through the social media and it is expected that it will bring a foundation of establishing smart business strategies by using the network indicators.

A study on the Success Factors and Strategy of Information Technology Investment Based on Intelligent Economic Simulation Modeling (지능형 시뮬레이션 모형을 기반으로 한 정보기술 투자 성과 요인 및 전략 도출에 관한 연구)

  • Park, Do-Hyung
    • Journal of Intelligence and Information Systems
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    • v.19 no.1
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    • pp.35-55
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    • 2013
  • Information technology is a critical resource necessary for any company hoping to support and realize its strategic goals, which contribute to growth promotion and sustainable development. The selection of information technology and its strategic use are imperative for the enhanced performance of every aspect of company management, leading a wide range of companies to have invested continuously in information technology. Despite researchers, managers, and policy makers' keen interest in how information technology contributes to organizational performance, there is uncertainty and debate about the result of information technology investment. In other words, researchers and managers cannot easily identify the independent factors that can impact the investment performance of information technology. This is mainly owing to the fact that many factors, ranging from the internal components of a company, strategies, and external customers, are interconnected with the investment performance of information technology. Using an agent-based simulation technique, this research extracts factors expected to affect investment performance on information technology, simplifies the analyses of their relationship with economic modeling, and examines the performance dependent on changes in the factors. In terms of economic modeling, I expand the model that highlights the way in which product quality moderates the relationship between information technology investments and economic performance (Thatcher and Pingry, 2004) by considering the cost of information technology investment and the demand creation resulting from product quality enhancement. For quality enhancement and its consequences for demand creation, I apply the concept of information quality and decision-maker quality (Raghunathan, 1999). This concept implies that the investment on information technology improves the quality of information, which, in turn, improves decision quality and performance, thus enhancing the level of product or service quality. Additionally, I consider the effect of word of mouth among consumers, which creates new demand for a product or service through the information diffusion effect. This demand creation is analyzed with an agent-based simulation model that is widely used for network analyses. Results show that the investment on information technology enhances the quality of a company's product or service, which indirectly affects the economic performance of that company, particularly with regard to factors such as consumer surplus, company profit, and company productivity. Specifically, when a company makes its initial investment in information technology, the resultant increase in the quality of a company's product or service immediately has a positive effect on consumer surplus, but the investment cost has a negative effect on company productivity and profit. As time goes by, the enhancement of the quality of that company's product or service creates new consumer demand through the information diffusion effect. Finally, the new demand positively affects the company's profit and productivity. In terms of the investment strategy for information technology, this study's results also reveal that the selection of information technology needs to be based on analysis of service and the network effect of customers, and demonstrate that information technology implementation should fit into the company's business strategy. Specifically, if a company seeks the short-term enhancement of company performance, it needs to have a one-shot strategy (making a large investment at one time). On the other hand, if a company seeks a long-term sustainable profit structure, it needs to have a split strategy (making several small investments at different times). The findings from this study make several contributions to the literature. In terms of methodology, the study integrates both economic modeling and simulation technique in order to overcome the limitations of each methodology. It also indicates the mediating effect of product quality on the relationship between information technology and the performance of a company. Finally, it analyzes the effect of information technology investment strategies and information diffusion among consumers on the investment performance of information technology.

Principal Characteristics of Pinus parviflora S. et Z. Native to the Dagelet Island (울릉도(鬱陵島) 섬잣나무의 특성(特性)에 관(關)한 연구(硏究))

  • Ahn, Kun Yong
    • Journal of Korean Society of Forest Science
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    • v.12 no.1
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    • pp.31-43
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    • 1971
  • In order to examine the taxonomic difference between the type of Pinus parviflora S. et Z. native to the Dagelet Island and the type of the species introduced to a number of places of the inland of South Korea, investigations on principal characters of needle, cone and seed were made with a hope to obtain informations on the evaluation of the species for possible use in the reforestation program in Korea in the future. Pinus parviflora is belonged to the Sub-genus Haploxylon of Genus Pinus and it has been speculated among dendrologists that this speoies is not monotypic. 308 rendomly selected trees from 8 different elevations of a natural stand of P. parviflora in the Dagelet Island, and 168 trees of P. parviflora growing at 15 different locations of the inland of South Korea were employed as samples along with 300 trees of P. koraiensis as control. The results obtained are summarized as follows: 1. The needle length of the Pinus parviflora of the Dagelet Island is longer than that of the species growing in the inland by 21-35 percent with statistical significancy. (Table 2) 2. In the cross section of needle, no resin canal was observed in about 50-70 percent of the sample trees of the Dagelet Island, whereas the resin canals appearing at external in most cases were observed in all sample trees from the inland. Consequently, the number of resin canals per needle was 0.4-0.9 with the Dagelet Island type and 2.0-2.7 with the inland type and these differences were statistically significant. (Table 3, Fig.2) 3. The Pinus parvviflora type of the Dagelet Island bas yellowish brown cones, and the Pinus parviflora type of Suwon and Kwangyang has redish brown cones. In both the length of cone and the number of cone scale, the difference between the type of the Dagelet Island and the type of the inland was also statistically significant. The cone scales of the Dagelet Island type are slightly opened, whereas the cone scales are widely opened with both of Suwon and Kwangyang type. (Table 4, Fig. 3) 4. the seed color, of the Dagelet Island type is yellowish brown, while it is greyish brown with Kwangyang and Suwon type. In the length and width of seed, the Dagelet Island type showed significantly larger values than that of the inland type. The length of seed was longest with the Kwangyang type being followed by Suwon and the Dagelet Island type in ordar. The seed wing of the Kwangyang type are longer than the seed, while that of the Dagelet Island type is degenerated to be shorter than the seed. (Table 5, Fig. 4) 5. The Pinus parviflora type of the Dagelat Island is similar in many respects to the southern type of Pinus parviflora of Japan except that many has no resin canals in the needle. 6. On the basis of the results obtained in this study, it may be concluded that the type of Pinus parviflora of the Dagelet Island is significantly different from the type of the species introduced to the inland and that there is no recognizable variation between the population of the different altitude of the Dagelet Island and the individual variation within population is also negligible. In the light of the high value of the tree not only as an ornamental tree but as an economical tree, The type of Pinus parviflora of the Dagelet Island is considered to be recommendable to be used for the future reforestation program of Korea.

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Diagnostic Values of Abdominal Ultrasonography in Patients with Fever and Abdominal Symptoms (발열과 복부 증상을 주소로 하는 환아에서 복부 초음파 검사의 진단적 의의에 관한 연구)

  • Lee, Mi-Kyung;Im, Chang-Sung;Ahn, Sun-Mi;Kim, Chang-Hi;Lee, Dong-Jin;Kwan, Joong-Hyuck;Park, Yong-Hoon
    • Journal of Yeungnam Medical Science
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    • v.12 no.2
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    • pp.191-202
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    • 1995
  • Purpose: Acute febrile illness in children frequently accompanies with abdominal symptoms such as vomiting, diarrhea, and abdominal pain, even if its etiology is not occured from the gastrointestinal tract. If the etiology of fever was unknown and the fever was accompanied with abdominal symptoms, we should be concerned about whether the etiology of fever was originated from the gastrointestinal tract or interpretated from the abnormality in the gastrointestinal tract. This study was performed to evaluate the diagnostic value of abdominal ultrasonography in patients with fever and abdominal symptoms. Methods: We reviewed retrospectively the medical records of abdominal ultrasonographic (US) findings of 60 cases of acute febrile illness with abdominal symptoms at department of Pediatrics, Ulsan Dongang General Hospital during the period from January 1994 to June 1995. Results: The abnormal abdominal US findings obtained were as follows. 1) The abnormal US findings were seen in 56 cases (93.3%). 2) The most common abnormal US finding was the enlarged mesenteric lymph nodes in 52 cases (86.7%) 3) The enlarged mesenteric lymph nodes with or without intra-abdominal fluid were seen in 30 cases (50.0%) of a wide variety of illnesses, so their diagnostic values were absent. 4) The enlarged mesenteric lymph nodes and splenomegaly with or without ileocecitis were seen in 7 cases. Among them, 4 cases (6.7%) were confirmed as typhoid fever. 5) The US findings in 6 cases of typhoid fever were the enlarged mesenteric lymph nodes in all cases (100%), splenomegaly in 4 cases (66.7%), ileocecitis in 1 case (16.7%), enlarged mesenteric lymph nodes and splenomegaly in 4 cases (66.7%), enlarged mesenteric lymph nodes, splenomegaly and ileocecitis in 1 cases (16.7%). 6) The enlarged mesenteric lymph nodes and the abnormalities around the appendix were seen in 7 cases (11.7%), which were confirmed as appendicitis all. 7) The thickening of wall in urinary bladder was seen in 2 cases (3.3%) of acute cystitis and acute hemorrhagic cystitis. 8) The subtle thickening of wall in colon was seen in 1 cases (1.7%) of shigellosis. Conclusions: The enlarged mesenteric lymph nodes, splenomegaly and ileocolitis on the abdominal ultrasonography in patients with fever and abdominal symptoms aree suggestive findings of typhoid fever. The enlarged mesenteric lymph nodes and the abnormalities around the appendix on abdominal ultrasonography make the rapid diagnosis of acute appendicitis and its complications, when physical examination is difficult in small children and diagnosis of their illnesses is obscure in patients with fever and abdominal pain.

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