• Title/Summary/Keyword: Frequency Change

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A study on algal bloom forecast system based on hydro-meteorological factors in the mainstream of Nakdong river using machine learning (머신러닝를 이용한 낙동강 본류 구간 수문-기상인자 조류 예보체계 연구)

  • Taewoo Lee;Soojun Kim;Junhyeong Lee;Kyunghun Kim;Hoyong Lee;Duckgil Kim
    • Journal of Wetlands Research
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    • v.26 no.3
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    • pp.245-253
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    • 2024
  • Blue-green algal bloom, or harmful algal bloom has a negative impact on the aquatic ecosystem and purified water supply system due to oxygen depletion in the water body, odor, and secretion of toxic substances in the freshwater ecosystem. This Blue-green algal bloom is expected to increase in intensity and frequency due to the increase in algae's residence time in the water body after the construction of the Nakdong River weir, as well as the increase in surface temperature due to climate change. In this study, in order to respond to the expected increase in green algae phenomenon, an algal bloom forecast system based on hydro-meteorological factors was presented for preemptive response before issuing a algal bloom warning. Through polyserial correlation analysis, the preceding influence periods of temperature and discharge according to the algal bloom forecast level were derived. Using the decision tree classification, a machine learning technique, Classification models for the algal bloom forecast levels based on temperature and discharge of the preceding period were derived. And a algal bloom forecast system based on hydro-meteorological factors was derived based on the results of the decision tree classification models. The proposed algae forecast system based on hydro-meteorological factors can be used as basic research for preemptive response before blue-green algal blooms.

Assessing the skill of seasonal flow forecasts from ECMWF for predicting inflows to multipurpose dams in South Korea (ECMWF 계절 기상 전망을 활용한 국내 다목적댐 유입량 예측의 성능 비교·평가)

  • Lee, Yong Shin;Kang, Shin Uk
    • Journal of Korea Water Resources Association
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    • v.57 no.9
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    • pp.571-583
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    • 2024
  • Forecasting dam inflows in the medium to long term is crucial for effective dam operation and the prevention of water-related disasters such as floods and droughts. However, the increasing frequency of extreme weather events due to climate change has made hydrological forecasting more challenging. Since 2000, seasonal weather forecasts, which provide predictions for weather variables up to about seven months ahead, and their hydrological interpretation, known as Seasonal Flow Forecasts (SFFs) have gained significant global interest. This study utilises seasonal weather forecasts from the European Centre for Medium-Range Weather Forecasts (ECMWF), converting them into inflow forecasts using a hydrological model for 12 multipurpose dams in South Korea from 2011 to 2020. We then compare the performance of these SFFs with the Ensemble Streamflow Prediction (ESP). Our results indicate that while SFFs are more effective for short-term predictions of 1-2 months, ESP outperforms SFFs for long-term predictions. Seasonally, the performance of SFFs is higher in October-November but lower from December to February. Moreover, our findings demonstrate that SFFs are highly effective in quantitatively predicting dry conditions, although they tend to underestimate inflows under wet conditions.

Characteristics of Flora on Dry Field Margins in Korean Peninsula (밭경작지 주변부의 식물 종조성 및 특성)

  • Kim, Myung-Hyun;Choi, Soon-Kun;Kim, Min-Kyeong;Choe, Lak-Jung;Hong, Seong-Chang;Jung, Goo-Bok;Cho, Kwang-Jin;Han, Donguk;Oh, Young-Ju;Lee, Wook-Jae;Yang, Dongwoo;Park, Sangkyu;Na, Young-Eun
    • Korean Journal of Environmental Agriculture
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    • v.34 no.2
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    • pp.77-90
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    • 2015
  • BACKGROUND: The field margins, which are uncultivated area of permanent vegetation located adjacent to field, play an important role in enhancing biodiversity in the agricultural ecosystem. This study focused on floristic characteristics on dry field margins in Korea Peninsula. METHODS AND RESULTS: This study was conducted at margins of 196 dry fields in 32 areas in 8 provinces in May and September 2013. The vascular plants of the dry field margins were listed 347 taxa which contain 73 families, 219 genera, 311 species, 1 subspecies, 30 varieties and 5 forms. Of these 347 taxa, 48 taxa were woody plants and 299 taxa were herbaceous plants. Among total 73 families, Compositae (17.6%) was the most dominant family, and followed Gramineae (15.9%), Polygonaceae (5.8%), Leguminosae (4.9%) and Cyperaceae (3.8%). Based on relative frequency values of survey fields, the appearance frequency of Digitaria ciliaris (89.8%) was the highest, and followed Acalypha australis (86.2%), Artemisia princeps (82.1%), Commelina communis (80.6%) and Portulaca oleracea (80.6%). Disturbance index of dry field margins was 55.0% at national level, and Gangwon region was the highest among the 8 regions at regional level. Life form spectrum was determined to be $Th-R_5-D_4-etype$. CONCLUSION: These results will be used fundamental data for studies to improve or even stabilize the current state of plant biodiversity in agricultural environments.

A Study on the Job Activities of the Emergency Nurses (응급실 근무 간호사의 업무분석)

  • 김광주;이향련;김귀분
    • Journal of Korean Academy of Nursing
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    • v.25 no.4
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    • pp.709-728
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    • 1995
  • The job related activities of sixty nine nurses, working in the emergency rooms of three university hospitals, were analyzed for six days according to preestablished checklist of nursing activities ; the frequency of these activities and the amount of time spent in each specific nursing activity. The established checklist was monitored every five minutes for the duration of the duty autu, thus producing 414 items of data. The data were not gathered on consecutive days but over the period of one month from May 6, 1994 to June 5, 1994. The following conclusions are derived from analysis of the data : 1. Twelve categories of nursing activities were obtained : The primary activity was communication related to the patient and all information pertaining to the patient. Other activities included maintaining the patient's record, observation and assessment of the patient, cooperation with other medical personnel, management of equipment and drugs, procedure and treatment, specimen collection, consultation and education for the patient, including drug management and personal hygiene and any other relevant education to the patient's condition. 2. The average frequency of categorized nursing activity can be classified as follows : communication related to patient was the highest at 17.6 times. The next was maintaining the patient's record at 17.3 times. The observation and assessment occurred 16.9 times. Consultation and education for patients and family, 8 times, medication, 5.7 times, and procedures and treatments, 6 times. 3. The average time required for each activity was as follows : 230.1 minutes (or maintaining the patient's record, 204.9 minutes for communication related to the patient, 199.2 minutes for observation and assessment, 71.2 minutes for medication, 66 minutes for consultation and education of the patient and family, and 51.8 minutes for procedures and treatment. 4. The most demanding nursing activity in the emergency room for the nurse was answering questions from the patient's family, maintaining communication between the medical staff, maintaining and reviewing the patient's charts, writing prescriptions and monitoring 1. V. infusion rates. 5. The most time consuming nursing activities for the emergency room nurse include maintaining and following the patient's charts, communication between the medical staff, answering questions from the patient's family, observation of the patient and relaying all of the appropriate patient information to the incoming nurses during a shift change. 6. The F-test was administered to measure the required time for the categorized nursing activities according to day, evening, and night-shift nurses. There were significant differences (p<.05) in specimen collection, observation and assessment, cooperation between medical staffs, personal hygiene, communication related to patient, education and re-search. Posterior multiple comparison test showed that specimen collection, cooperation between medical staffs and personal hygiene were mostly done by the evening-shift nurses. Also most observations and assessments were done by the night-shift nurses. Education and communication to patients were done by day-shift nurses. Thus there were significant difference between shifts for the main nursing activities. So there should considev a reallocation of the duty of nurses on each shift. 7. The F-test also indicated that there wes a similarity in time duration for procedures and treatments and for cooperation between medical staff and nurses in all three hospitals. However, the remaining categories of nursing activities also showed a significant difference between the three hospitals. This indicated that there were differences in each emergency room that influence time for each categorized nursing activities and this should be given more consideration. Recommendations : 1. A seasonal difference should be considered in the activities of nurses in the emergency room and a comparative analysis should be carried out to deter-mine seasonal differentiation. 2. A study on more objectively measurable nursing activities should be administered as well as one determining the subjective responds towards nursing activities in the emergency room.

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A Study On the Operating Room Nurses' Performances of Duties and Their Fatigue (수술실간호사의 직무수행과 피로에 관한 연구)

  • Park, Jeong Sook
    • Korean Journal of Occupational Health Nursing
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    • v.6 no.2
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    • pp.110-127
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    • 1997
  • The aim of this study is to present the basic datum for the promotion of effectiveness and improvement of nursery tasks, by grasping the situation of operating room nurses tasks and the degree of their fatigue. For these researches, 70 nurses out of the operating rooms of 3 university-affiliated hospitals-two in Seoul and one in Pusan, were chosen at random by a non-probability sampling method. These researches were done from April 14 to April 26 in 1997 by questionairing method. The questionaire was composed of 30 items, which asks the examinees of their physical, mental, and neurosensory symptoms, with 10 items respectively. The reliability of the research instrument was turned out very high with Cronbach's ${\alpha}=.9376$. The datum were electronically processed using Statistics Program for Social Sciences(SPSS). The analysis of datum in this study has a general character, in which the demosociological character and the special ex-officio character was calculated by frequency and percentage. The situation of tasks in operating rooms was calculated by frequency and percentage. The fatigue of operating room nurses was calculated by average and standard deviation. To compare the fatigue with regard to the character of operating room nurse's tasks, t-test and F-test(ANOVA) were used after the character of variations, and the variations at the level of P<.05 which might have some meaning was verified after the fact with Duncan's Multiple Range(DMR). The results of this research are as follows : 1) The nurses working in operating rooms show their fatigue in three fields-in Group I physical symptoms 3.28, in Group III neurosensory symptoms 2.85, and in Group II mental symptoms 2.73, which shows I Dominant type (general type). 2) They complain, in Group I they are "feeling the heavy legs," 3.28 and in Group II they "occasionally forget soon what to do," 3.09. and in Group III, they "feel lumbago," 3.47, which is the highest rate of the three. The highest rate results from the character of their tasks, in which they have to move rapidly the heavy appliances and do their jobs standing many hours, especially wearing heavy radiation protector. 3) As to transportation, subway using group feel the greatest fatigue, 3.18(F=4.315, P=.008). 4) As to department, nurses in the orthopedic's surgery part feel the greatest fatigue, 3.26(F=2.040, P=.050). 5) As to the change of physical symptoms, the group answering that they found physical abnormality after working in operating rooms show the greatest fatigue, 3.12(t=-3.13, P=.003). 6) At to the general circumstances, the group answering that they receive insufficient consideration on their physical abnormality in their department, show the greatest fatigue, 3.10(F=3.200, P=0.47). 7) As to the relation with superior officers, the group answering that their superior officer has an impetuous temperament, show great fatigue, 3.11(F=4.855, P=.011). 8) As to the time of feeling fatigue, the fatigue reaches the highest point 1~2 hours after operations, 3.04(F=2.703, P=.046). 9) When they feel fatigue after scrub nurse duties, they feel the greatest fatigue 2 hours after the duties, 3.09( F=2.841, P=.038). 10) As to the operation instruments, when they use complex instruments borrowing from the outside in addition to the basic instruments, their fatigue becomes the greatest, 3.09(F=7.831, P=.000). 11) As to the kind of operation, when they participate in orthopedic's surgery operations, they feel the greatest fatigue, 3.18(F=4.362, P=.000). With the above results, it is proved that the degree of operating room nurses' fatigue is considerably high. So it may be concluded that the measure for lessening the fatigue should be find immediately, not on the level of personal matters but on the level of hospital nursing administration.

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Determination of Appropriate Sampling Frequency and Time of Multiple Blood Sampling Dual Exponential Method with $^{99m}Tc$-DTPA for Calculating GFR (사구체여과율 계산을 위한 $^{99m}Tc$-DTPA를 이용한 다중 채혈 이중지수법의 적정 채혈 횟수 및 시간의 선정)

  • Kim, Chung-Ho;O, Joo-Hyun;Chung, Yong-An;Yoo, Ie-Ryung;Sohn, Hyung-Sun;Kim, Sung-Hoon;Chung, Soo-Kyo;Lee, Hyoung-Koo
    • Nuclear Medicine and Molecular Imaging
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    • v.40 no.1
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    • pp.33-39
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    • 2006
  • Purpose: To determine appropriate sampling frequency and time of multiple blood sampling dual exponential method with $^{99m}Tc$-DTPA for calculating glomerular filtration rate (GFR). Materials & Methods: Thirty four patients were included in this study. Three mCi of $^{99m}Tc$-DTPA was intravenously injected and blood sampling at 9 different times, 5ml each, were done. Using the radioactivity of serum, measured by gamma counter, the GFR was calculated using dual exponential method and corrected with the body surface area. Using spontaneously chosen 2 data points of serum radioactivity, 15 collections of 2-sample GFR were calculated. And 10 collections of 3-sample GFR and 12 collections of 4-sample GFR were also calculated. Using the 9-sample GFR as a reference value, degree of agreement was analyzed with Kendall's $\tau$ correlation coefficients, mean difference and standard deviation. Results: Although some of the 2-sample GFR showed high correlation coefficient, over or underestimation had evolved as the renal function change. The 10-120-240 min 3-sample GFR showed a high correlation coefficient (${\tau}=0.93$), minimal difference ($Mean{\pm}SD=-1.784{\pm}3.972$), and no over or underestimation as the renal function changed. The 4-sample GFR showed no better accuracy than the 3-sample GFR. Conclusions: In the wide spectrum of renal function, the 10-120-240 min 3-sample GFC could be the best choice for estimating the patients' renal function.

The Roles of the TSH Receptor Antibodies in Autoimmune Thyroid Diseases (자가면역성 갑상선질환에서 TSH 수용체 항체의 역활에 관한 연구)

  • Koh, Chang-Soon
    • The Korean Journal of Nuclear Medicine
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    • v.20 no.2
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    • pp.85-100
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    • 1986
  • To evaluate the clinical and pathogenetic roles of TSH receptor antibodies in autoimmune thyroid diseases, TBII were measured by TSH-radioreceptor assay methods in 352 patients with Graves' disease, 108 patients with other thyroid diseases and 69 normal persons. The normal range of TBII activity was less than 15%. The frequencies of detectable TBII in 169 patients with untreated Graves' disease, 31 patients with hyperthyroidism under treatment and 70 patients with euthyrodism under treatment were 92.4%, 87.1% and 54.3% respectively. However 12 (21.8%) out of 55 patients who have been in remission more than one year after discontinuation of antithyroid drugs treatment had detectable TBII activities in their sera. In 196 patients with untreated Graves' disease, the frequency of TBII increased by increasing size of goiter and the frequency of proptosis was significantly high in patients whose TBII activities were more than 60%. TBII activities were roughly correlated with total $T_3,\;T_4$ and free $T_4$ index but low $\gamma^2$ value(less than 0.1). In 67 patients with Graves' disease who were positive TBII before antithyroid drugs treatment, TBII activities began to decrease from the third months and it was converted to negative in 35.8% of patients at 12 months after treatment. There were no significant differences of the declining and disappearing rates of TBII activities between high dose and conventional dose groups. TBII activities were significantly increased initially (2-4 months) and then began to decrease from 5-9 months after $^{131}I$ treatment. There were two groups, one whose TBII activities decreased gradually and the other did not change untill 12 months after subtotal thyroidectomy. Although preoperative clinical and laboratory findings of both groups were not different, TBII activities of non-decreasing group were significantly higher than those of decreasing group$(74.6{\pm}18.6%\;vs\;39.2{\pm}15.2%;\;P<0.01)$. Thirty three(55.9%) out of 59 patients with Graves' disease relapsed within 1 year after discontinuation of antithyroid drugs. The positive rate of TBII at the end of antithyroid drug treatment in relapse group(n=33) was significantly higher than those in remission group (n=26) (63.6% vs 23.1%; P < 0.05). The mean value of TBII activities at the end of antithyroid drug treatment in relapse group was significantly elevated $(29.7{\pm}21.4%\;vs\;14.7{\pm}11.1%,\;P<0.05)$. Positive predictive value of TBII for relapse was 77.8%, which was not different from those of TRH nonresponsiveness(78.6%). The frequencies of detectable TBII in 68 patients with Hashimoto's thyroiditis, 10 patients with painless thyroiditis and 5 patients subacute thyroiditis were 14.7%, 20% and 0%, respectively. However in 25 patients with primary nongoitrous myxedema, 11 patients(44%) showed TBII activities in their sera. 9 out of 11 patients who had TBII activities in their sera showed high TBII activities(more than 70% binding inhibition) and their IgG concentrations showing 50% binding inhibition of $^{125}I-bTSH$ to the TSH receptor were ranges of 0.1-2.6 mg/dl. One patient who had high titer of TBII in her serum delivered a hypothyroid baby due to transplacental transfer of maternal TBII. These findings suggested that 1) TSH receptor antibodies are closely related to a pathogenetic factor of Graves' hyperthyroidism and of some patients with primary non-goitrous myxedema, 2) measurement of TSH receptor antibodies is helpful in evaluating the clinical outcome of patients with Graves' disease during antithyroid drug treatment and in predicting the neonatal transient hypothyroidism of baby delivered from primary myxedema patients. 3) there are 2 or more different types of TSH receptor antibodies in autoimmune thyroid diseases including one which stimulates thyroid by binding to the TSH receptor and another which blocks adenylate cyclase stimulation by TSH.

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A Study of the Factors Influencing Behavioral Intention for Organic Food: Using the Theory of Planned Behavior (유기농식품에 대한 소비자의 구매의도 영향요인 분석 계획적 행동이론을 중심으로)

  • Choi, Hwa-Sun;Lee, Kwang-Keun
    • Journal of Distribution Science
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    • v.10 no.2
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    • pp.53-62
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    • 2012
  • Well-being is a reflection of current sociocultural trends that focus on the quality of life based on economic growth. Furthermore, organic food is believed to help people maintain good health and therefore leads to increased consumption of organic foods. Therefore, consumer interest in organic food is increasing, causing its market to grow, and this trend will be maintained in the future. The abuse of agricultural pesticides, gene manipulation, and bovine spongiform encephalopathy has caused consumers to worry about food safety. The well-being trend has also contributed to consumers' growing interest inorganic food and organic agricultural products. A consumer's choice offood is a complex processes affected by various factors. In particular, organic food is considered an individualistic merit good, considering the consumers' preferences related to certification policies. Therefore, various factors such as personal characteristics and sense of value could affect consumers' decisions. This research focused on an analysis of the factors influencing consumers' purchasing intention for organic food on the basis of an increase in organic food consumption. The research method was based on the theory of planned behavior (TPB). Factors such as consumer characteristics regarding food consumption, purchasing frequency, and other factors affecting purchasing intention were presented. The hypothesis was set using advanced research and stated that it is easier to forecast purchasing intentions by combining the theory of planned behavior and personal characteristics of consumer. The results show that two dimensions, attitude and perceived behavioral control, have statistically significant influence on the purchasing intention. It can be said that a positive attitude toward organic foods in particular increases the possibility of purchasing intention. In addition, consumers who consume more organic food products are more likely to have positive attitudes, and, in the past, purchasing frequency has positively influenced purchasing intention of organic foods. Consumers' negative feelings about the non-purchase of organic foods also showed a negative influence on purchasing intentions. In other words, even though consumers feel uncomfortable when not consuming organic food products, they do not try to purchase such products because of this feeling of discomfort. Furthermore, the subjective norm and the behavioral control of food-related involvement do not have a statistically significant influence on the purchasing intention or attitudes. This research verified the influence of factors related to purchasing intention. This study has several limitations: (1) even though consumers' responses can change based on the type of food, the types of food were not classified in this study; (2) future studies are necessary to analyze the attitudes of consumers on the basis of their purchasing experiences with organic foods.

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Issue tracking and voting rate prediction for 19th Korean president election candidates (댓글 분석을 통한 19대 한국 대선 후보 이슈 파악 및 득표율 예측)

  • Seo, Dae-Ho;Kim, Ji-Ho;Kim, Chang-Ki
    • Journal of Intelligence and Information Systems
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    • v.24 no.3
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    • pp.199-219
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    • 2018
  • With the everyday use of the Internet and the spread of various smart devices, users have been able to communicate in real time and the existing communication style has changed. Due to the change of the information subject by the Internet, data became more massive and caused the very large information called big data. These Big Data are seen as a new opportunity to understand social issues. In particular, text mining explores patterns using unstructured text data to find meaningful information. Since text data exists in various places such as newspaper, book, and web, the amount of data is very diverse and large, so it is suitable for understanding social reality. In recent years, there has been an increasing number of attempts to analyze texts from web such as SNS and blogs where the public can communicate freely. It is recognized as a useful method to grasp public opinion immediately so it can be used for political, social and cultural issue research. Text mining has received much attention in order to investigate the public's reputation for candidates, and to predict the voting rate instead of the polling. This is because many people question the credibility of the survey. Also, People tend to refuse or reveal their real intention when they are asked to respond to the poll. This study collected comments from the largest Internet portal site in Korea and conducted research on the 19th Korean presidential election in 2017. We collected 226,447 comments from April 29, 2017 to May 7, 2017, which includes the prohibition period of public opinion polls just prior to the presidential election day. We analyzed frequencies, associative emotional words, topic emotions, and candidate voting rates. By frequency analysis, we identified the words that are the most important issues per day. Particularly, according to the result of the presidential debate, it was seen that the candidate who became an issue was located at the top of the frequency analysis. By the analysis of associative emotional words, we were able to identify issues most relevant to each candidate. The topic emotion analysis was used to identify each candidate's topic and to express the emotions of the public on the topics. Finally, we estimated the voting rate by combining the volume of comments and sentiment score. By doing above, we explored the issues for each candidate and predicted the voting rate. The analysis showed that news comments is an effective tool for tracking the issue of presidential candidates and for predicting the voting rate. Particularly, this study showed issues per day and quantitative index for sentiment. Also it predicted voting rate for each candidate and precisely matched the ranking of the top five candidates. Each candidate will be able to objectively grasp public opinion and reflect it to the election strategy. Candidates can use positive issues more actively on election strategies, and try to correct negative issues. Particularly, candidates should be aware that they can get severe damage to their reputation if they face a moral problem. Voters can objectively look at issues and public opinion about each candidate and make more informed decisions when voting. If they refer to the results of this study before voting, they will be able to see the opinions of the public from the Big Data, and vote for a candidate with a more objective perspective. If the candidates have a campaign with reference to Big Data Analysis, the public will be more active on the web, recognizing that their wants are being reflected. The way of expressing their political views can be done in various web places. This can contribute to the act of political participation by the people.

A Study on Requirement and Degree of the Satisfaction about Cosmeceuticals of Women (우리나라 여성들의 기능성화장품에 대한 요구 및 만족도 연구)

  • Kim Kang-Mi;Kim Ju-Duck
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.30 no.4 s.48
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    • pp.571-582
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    • 2004
  • Recently the well-being, which is regarded as the new cultural code, has brought a new change in the cosmetic industry. The application of the functional products is getting mere and lots of functional cosmetics are now diversifying from the skin-care into the make-up as well as the herbal products. So the future in the market of functional cosmetic products is prospected to be positive. Therefore, cosmetic companies need an approach bases on the concept of the well-being. So to speak, they need to understand the needs of customers accurately from the customers point of view. Also it is a crucial issue that how the unique characteristics of functional cosmetic products as well as the development of products base on the concept of well-being make in balance. In this study, we attempt to inspect the advanced domestic market of the functional products due to the well-being trend and try to propose an option of making an advance it through the customers survey (for example, their need and their satisfaction on the functional products, etc) on the functional cosmetic products. For this purpose, it has been surveyed on adult female customers aged 19 to 60 located in Seoul and Gyeonggi province. 379 questionnaires among 510 were used in the final analysis. Collected data was analyzed using the statistical package for the social science (SPSS) program that can give the information about the general characteristics of the subjects like the frequency and percentage. And we used Cronbach's u reliability test, $x^2\;(chi-square)$ frequency analysis, t-test, and one-wat ANOVA to investigate the customers need, their degree of the satisfaction on the functional products of their own, factors of their perception on the quality on them. We think that the results of our study can act not only as the fundamental data on the customers need, their usage pattern, and their degree of the satisfaction, but also as the important tips of planning the marketing strategies.