• Title/Summary/Keyword: research data

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Product Recommender Systems using Multi-Model Ensemble Techniques (다중모형조합기법을 이용한 상품추천시스템)

  • Lee, Yeonjeong;Kim, Kyoung-Jae
    • Journal of Intelligence and Information Systems
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    • v.19 no.2
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    • pp.39-54
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    • 2013
  • Recent explosive increase of electronic commerce provides many advantageous purchase opportunities to customers. In this situation, customers who do not have enough knowledge about their purchases, may accept product recommendations. Product recommender systems automatically reflect user's preference and provide recommendation list to the users. Thus, product recommender system in online shopping store has been known as one of the most popular tools for one-to-one marketing. However, recommender systems which do not properly reflect user's preference cause user's disappointment and waste of time. In this study, we propose a novel recommender system which uses data mining and multi-model ensemble techniques to enhance the recommendation performance through reflecting the precise user's preference. The research data is collected from the real-world online shopping store, which deals products from famous art galleries and museums in Korea. The data initially contain 5759 transaction data, but finally remain 3167 transaction data after deletion of null data. In this study, we transform the categorical variables into dummy variables and exclude outlier data. The proposed model consists of two steps. The first step predicts customers who have high likelihood to purchase products in the online shopping store. In this step, we first use logistic regression, decision trees, and artificial neural networks to predict customers who have high likelihood to purchase products in each product group. We perform above data mining techniques using SAS E-Miner software. In this study, we partition datasets into two sets as modeling and validation sets for the logistic regression and decision trees. We also partition datasets into three sets as training, test, and validation sets for the artificial neural network model. The validation dataset is equal for the all experiments. Then we composite the results of each predictor using the multi-model ensemble techniques such as bagging and bumping. Bagging is the abbreviation of "Bootstrap Aggregation" and it composite outputs from several machine learning techniques for raising the performance and stability of prediction or classification. This technique is special form of the averaging method. Bumping is the abbreviation of "Bootstrap Umbrella of Model Parameter," and it only considers the model which has the lowest error value. The results show that bumping outperforms bagging and the other predictors except for "Poster" product group. For the "Poster" product group, artificial neural network model performs better than the other models. In the second step, we use the market basket analysis to extract association rules for co-purchased products. We can extract thirty one association rules according to values of Lift, Support, and Confidence measure. We set the minimum transaction frequency to support associations as 5%, maximum number of items in an association as 4, and minimum confidence for rule generation as 10%. This study also excludes the extracted association rules below 1 of lift value. We finally get fifteen association rules by excluding duplicate rules. Among the fifteen association rules, eleven rules contain association between products in "Office Supplies" product group, one rules include the association between "Office Supplies" and "Fashion" product groups, and other three rules contain association between "Office Supplies" and "Home Decoration" product groups. Finally, the proposed product recommender systems provides list of recommendations to the proper customers. We test the usability of the proposed system by using prototype and real-world transaction and profile data. For this end, we construct the prototype system by using the ASP, Java Script and Microsoft Access. In addition, we survey about user satisfaction for the recommended product list from the proposed system and the randomly selected product lists. The participants for the survey are 173 persons who use MSN Messenger, Daum Caf$\acute{e}$, and P2P services. We evaluate the user satisfaction using five-scale Likert measure. This study also performs "Paired Sample T-test" for the results of the survey. The results show that the proposed model outperforms the random selection model with 1% statistical significance level. It means that the users satisfied the recommended product list significantly. The results also show that the proposed system may be useful in real-world online shopping store.

Experimental Comparison and Analysis of Measurement Results Using Various Flow Meters (유량측정 기기별 측정성과에 대한 실험적 비교분석)

  • Lee, Jae-Hyug;Lee, Suk-Ho;Jung, Sung-Won;Kim, Tae-Woong
    • Journal of Wetlands Research
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    • v.12 no.1
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    • pp.95-103
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    • 2010
  • Discharge data examine the process of hydrologic cycle and used significantly in water resource planning and irrigation and flood control planning. However, it needs lots of time and money to get the discharge data. So discharge rating curve is usually used in converting discharge data. Therefore reliability of discharge rating curve absolutely depends on quality of discharge data. Many engineers who study hydrologic engineering make high quality discharge data to develop reliable discharge rating curve. And they carry out research on standard and method of discharge measurement, and equipment improvement. Now various flow meters are utilized to make discharge data in Korea. However, accuracy of equipment and experimental research data from measurement are not enough. In this paper, constant discharge flowed through standard concrete channel, and the velocity is measured using various flow meters. Also Discharge is calculated by measured data to compare and analyze. The equipment for the experiment is Price AA(USGS Type AA Current meter), flow meter, ADC, C2 small current meter, flow tracker, Electromagnetic current meter. The discharge got form various flow meters which are widely used for discharge measurement. The various depths of water were examined and compared such as 0.30 m, 0.35 m, 0.40 m, 0.45 m, 0.50 m, 0.55 m. The experiment progresses a round-measurement on 6-case. Wading measurement(one point method : the 60 % height in surface of the water) was applied to improve creditability and accuracy among measurement methods. USGS Type AA current Meter, Flow Meter, ADC, C2 Small Current meter got the certificate of quality guaranteed. So the results of experiment were used to compare discharge. The Results showed the difference based on USGS Type AA current Meter at average discharge and velocity. Electromagnetic current meter made differences over $\pm$ 10 % and Flow Meter made differences under $\pm$ 10 %. Also ADC, Flow Meter, C2 Small Current meter made differences under $\pm$ 5 %.

Home Range Analysis of a Pair of Gorals (Naemorhedus caudatus) Using GPS Collar According to the Elevation Change, in the North Gyeongbuk Province(Uljin) of Korea (경북북부지역(울진) 산양(Naemorhedus caudatus) 암·수 한 쌍의 행동권 및 고도변화에 따른 행동권 분석)

  • Cho, Chea-Un;Kim, Ki-Yoon;Kim, Kyu-Cheol;Kim, Hyun-Min;An, Jae-Yong;Lee, Bae-Keun;Park, Jong-Gil
    • Journal of the Korean Association of Geographic Information Studies
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    • v.18 no.1
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    • pp.135-146
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    • 2015
  • This study was carried out to understand ecological characteristics of Korean goral such as home range, seasonal home range and habitat use and used for Korean goral restoration and conservation, through a pair of gorals in the north Gyeongbuk province of Korea. With data from GPS collars, we analyzed the behavioral characteristics of the endangered Korean gorals(n=2) in Uljin area from June 2013 to July 2014. As a result, their home range was $1.38{\pm}0.24km^2$ in MCP 95%, $0.81{\pm}0.09km^2$ in FK 95% and $0.15{\pm}0.16km^2$ in FK 50% (t=8.118, p>0.05). Seasonal home range for MCP 95% was $0.74{\pm}0.31km^2$ > (winter) > $0.71{\pm}0.27km^2$ (spring) > $0.61{\pm}0.06km^2$ (autumn) > $0.27{\pm}0.04km^2$ (summer) (F=2.135 p>0.05). It showed that home range in winter was the largest and that in summer was the smallest. Mean elevation of male for seasonal habitat use was $440.18{\pm}71.32m$ in summer and that of female was $727.25{\pm}99.98m$ in spring. The lowest altitude for male was $372.72{\pm}70.79$ and female was $664.60{\pm}139.71m$. It meant that there were seasonal change and thus annual and seasonal behavior characteristics for both sexes had different correlation according to elevation change. Although in this study the correlation with prey in habitat and the changes of habitat disturbance were not clearly investigated, We could understand goral home range and habitat use through research data.

Development of Parking Space Forecast Model for Large Traffic-inducing Facilities Considering Surrounding Circumstance (주변 환경을 고려한 대규모 교통유발시설 주차면산정 모형개발에 관한 연구 - 판매시설을 중심으로 -)

  • Park, Je jin;Oh, Seok Jin;Kim, Sung Hun;Ha, Tae Jun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.37 no.3
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    • pp.593-601
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    • 2017
  • With the rapid industrial development and national economic advance since 1970, the national income of Korea has sharply increased. As a result, issues regarding city expansion, urban concentration, increase in the number of registered motor vehicles, and increase in traffic have caused transportation issues such as traffic congestion and problems with parking. Especially, enforcement ordinances and rules have been established on installation and management of parking lots to solve problems with parking which are raised as social problems such as conflict with neighbors but the flexible calculation of legal parking space has the limitations because of the diversity and complex functionality of purposes of facilities. Accordingly, this study attempted to supplement such demerit of the parking space demand forecast method based on the legally required number of parking spaces and average unit requirement in the parking space supply. This study estimated the required number of parking spaces by analyzing existing literature, collecting field research data, and analyzing the factors that have an impact on the parking demand. Also, it compared the required number of parking spaces based on the average unit requirement as well as the required number of parking spaces by the forecast model based on the cumulative number of motor vehicles parked. The result was that the required number of parking space based on average unit requirement was less than the cumulative number of motor vehicles parked by 9.99%. Meanwhile, the required number of parking spaces by the forecast model was more than the cumulative number of motor vehicles parked by 4.37%. Therefore, it is believed that the parking space forecast model is more efficient than the others in estimating there quired parking space. The parking space forecast model of this study consider different environmental factors to enable practical parking demand forecast considering the local characteristics and thus supply the parking space in an efficient way.

The Effects of Microcurrent Stimulation on the Astrocytes Proliferation at Injured Brain of Rabbit (극저전류자극이 손상된 토끼 뇌의 별아교세포 증식에 미치는 효과)

  • Kim, Ji-Sung;Min, Kyoung-Ok
    • Journal of Korean Physical Therapy Science
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    • v.9 no.3
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    • pp.107-119
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    • 2002
  • Astrocyte, which shares the greatest part of the brain (about 25%), is a land of glial cell that composes the central nervous system along with microglia, ependymal cell and oligodendroglia. It has 7-9nm of fibers in its cytoplasma, which are composed of glial fibrillary acidic protein (GFAP) and vimentin. As for the functions of the astrocyte, it has, so far, been supposed that the astrocyte will play a cytoskeletal role in maintaining the structure of the cerebrum, play a role as a blood-brain barrier so that it can induce migration of the neuron in its development and substances in the blood cannot go into the nervous tissue, and a role of immunology and phagocytosis. However, it was revealed today that it will be a role in preventing expansion of injury by attaching itself to the connective tissue such as the vessel and the pia mater when the nervous tissue or the arachnoid is injured. Microcurrent stimulation can control current, on the basis of A unit. That is, with such devices using it, it is possible to sense, from the outside, the injured current(wound current) of the lesion and to change it into the normal current, thereby promoting the restoration of the cells. In order to examine the effects of microcurrent stimulation on the injured astrocytes in the rabbits, this study was conducted with 24 New Zealand White Rabbit as its subjects, which were divided into 8 animals of the experiment group and 16 animals of the control group. After the animals in the experiment group were fixed to the stereotaxic apparatus, their hair was removed and their premotor area(association area) perforated by the micro-drill for skull-perforation with the depth of 8mm from the scalp. In one week after the injury, 4 animals in the control group and 8 animals in the experiment group were sacrificed and examined with immunohistochemical method. And in three weeks, the remaining 4 animals in the control group and 8 animals in the experiment group were also sacrificed and examined with the same way. The conclusion has been drawn as follows : In the control group sacrificed in one week after the injury, the astrocytes somewhat increased, compared with the normal animals, and in the group sacrificed in three weeks after the injury, they increased more (p < 0.05). The experiment group A in one week showed a little increase, but there was no significant differences, but the experiment group in three weeks showed more increase, compared with the experiment group in one week (p < 0.05). The experiment group B in one week showed more increase than the control group or the experiment group A, and the experiment group in three weeks showed more increase than the experiment group in one week (p < 0.05). Among the astrocytes, fibrous astrocytes were mostly observed, increasing as they are close to the lesion, and decreasing as they are remote from it. The findings show that microcurrent can cause the astrocytes to proliferate and that it will be more effective to stimulate the cervical part somewhat remote from the lesion rather than to directly stimulate the part of the lesion. Thus, microcurrent stimulation can be one of the methods that can activate the reaction of astrocytes, which is one of the mechanism for treating cerebral injury with hemorrhage. Therefore, this study will be used as basic research data for promoting restoration of functions in the patient with injury in the central nervous system.

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Modeling and Intelligent Control for Activated Sludge Process (활성슬러지 공정을 위한 모델링과 지능제어의 적용)

  • Cheon, Seong-pyo;Kim, Bongchul;Kim, Sungshin;Kim, Chang-Won;Kim, Sanghyun;Woo, Hae-Jin
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.10
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    • pp.1905-1919
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    • 2000
  • The main motivation of this research is to develop an intelligent control strategy for Activated Sludge Process (ASP). ASP is a complex and nonlinear dynamic system because of the characteristic of wastewater, the change in influent flow rate, weather conditions, and etc. The mathematical model of ASP also includes uncertainties which are ignored or not considered by process engineer or controller designer. The ASP is generally controlled by a PID controller that consists of fixed proportional, integral, and derivative gain values. The PID gains are adjusted by the expert who has much experience in the ASP. The ASP model based on $Matlab^{(R)}5.3/Simulink^{(R)}3.0$ is developed in this paper. The performance of the model is tested by IWA(International Water Association) and COST(European Cooperation in the field of Scientific and Technical Research) data that include steady-state results during 14 days. The advantage of the developed model is that the user can easily modify or change the controller by the help of the graphical user interface. The ASP model as a typical nonlinear system can be used to simulate and test the proposed controller for an educational purpose. Various control methods are applied to the ASP model and the control results are compared to apply the proposed intelligent control strategy to a real ASP. Three control methods are designed and tested: conventional PID controller, fuzzy logic control approach to modify setpoints, and fuzzy-PID control method. The proposed setpoints changer based on the fuzzy logic shows a better performance and robustness under disturbances. The objective function can be defined and included in the proposed control strategy to improve the effluent water quality and to reduce the operating cost in a real ASP.

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A Study on the Effect of 2010 HNS Convention on Korean Industry (위험·유해물질 피해보상 국제협약의 우리 산업계에 대한 영향 고찰)

  • Kim, Ji-Hong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.1
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    • pp.57-64
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    • 2020
  • The IOPC Fund general assembly reported that the International Convention on Liability and Compensation for Damage in Connection with the Carriage of Hazardous and Noxious Substances by Sea (known as the HNS Convention) will meet the requirement for the convention to take ef ect between 2021 and 2022. When the convention comes into effect, the liability-limit insurance of the HNS transport ship will be enforced and the shipper receiving the HNS will pay the share of the contribution from the International Fund for damages exceeding the limit of the ship's liability insurance. Korea is one of the major shipping and shipper countries in the world; thus, this study aimed to the need to analyze the effect of the convention on the related industries. The survey of ships and contribution targets analyzed the research data of the Ministry of Oceans and Fisheries. The P&I premium estimation was reviewed by the Korea Shipping Association and the K P&I as insured ships. In addition, the contribution of the HNS cargo volume was analyzed in an annual report by a representative international association for each cargo. About 1,500 ocean-going and domestic vessels have been identified as ships subject to the convention. The effect of changes in premiums under the convention was minimal for most ships. The effect of the shipping industry is expected, with about 150 domestic tankers expected to increase insurance premiums. In the case of shipper industries, 52 freight terminals were found to be eligible for the payment of the share of the international fund, as the proportion of freight volume in Korea was ranked second to fourth in the world by individual HNS accounts. This implies the obligation to pay contributions according to the convention. Considering the status of HNS transport ships entering and leaving ports and the quantity of HNS cargo, it can be concluded that the validity of Korea's convention is sufficient and that, it is necessary to coordinate with global major shipper countries.

An Analysis of Research Trends Related to Software Education for Young Children in Korea (유아의 소프트웨어 교육 관련 국내 최근 연구의 경향 분석)

  • Chun, Hui Young;Park, Soyeon;Sung, Jihyun
    • Korean Journal of Child Education & Care
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    • v.19 no.2
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    • pp.177-196
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    • 2019
  • Objective: This study aims to analyze research trends related to software education for young children, focusing on studies published in Korea from 2016 to 2019 March. Methods: A total of 26 research publications on software education for young children, searched from Korea Citation Index and Research Information Sharing Service were identified for the analysis. The trend in these publications was classified and examined respectively by publication dates, types of publications, and the fields of study. To investigate a means of research, the analysis included key topics, types of research methods, and characteristics of the study variables. Results: The results of the analysis show that the number of publications on the topic of software education for young children has increased over the three years, of which most were published as a scholarly journal article. Among the 26 research studies analyzed, 16 (61.5%) are related to the field of early childhood education or child studies. Key topics and target subjects of the most research include the curriculum development of software education for young children or the effectiveness of software education on 4- and 5-year-old children. Most of the analyzed studies are experimental research designs or in the form of literature reviews. The most frequently studied research variable is young children's cognitive characteristics. For the studies that employ educational programs, the use of a physical computing environment is prevalent, and the most frequently used robot as a programming tool is "Albert". The duration of the program implementation varies, ranging from 5 weeks to 48 weeks. In the analyzed research studies, computational thinking is conceptualized as a problem-solving skill that can be improved by software education, and assessed by individual instruments measuring sub-factors of computational thinking. Conclusion/Implications: The present study reveals that, although the number of research publications in software education for young children has increased, the overall sufficiency of the accumulated research data and a variety of research methods are still lacking. An increased interest in software education for young children and more research activities in this area are needed to develop and implement developmentally appropriate software education programs in early childhood settings.

Food Preferences and Nutrient Intakes of College Students in Kangwon Province (강원도 지역 대학생들의 음식 기호도 및 영양 섭취 실태 조사연구)

  • 최영심;유양자;김종군;남상명;정명은;정차권
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.30 no.1
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    • pp.175-182
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    • 2001
  • The main focus of this study was set to help college students in Kangwon province to improve and correct dietary habits and to maintain healthy life. The nutritional status and food preference of college students were examined from May to July, 1999. The collection of the research data has been made on the basis of questionnaries for 184 college students residing in Kangwon province. Statistical analysis of the data was performed using SAS package program for descriptive frequency and statistical significance. The meal skipping ratio of the subjects were 2% and for the reasons of meal skipping 45% responded "lack of time". As for main dishes, cooked rice turned out to be the most preferred by the subjects and the second and third favored by female students were bread and noodle respectively. Most preferred side-dishes were meat soup, kimchi, laver Kui,squid Bockeum, fried squid, beef Chon, squid Chorim, soy Namul, Dubuk Changachi and squid Muchim. Less preferred side-dishes include radish soup, white kimchi, mugwort fry, liver Bockeum, liver sheon and egg plant Kui. No one-plate food was disliked by the subjects. Male liked Manndukuk and female liked cuttle fish rice. The intakes of nutrient except for energy, iron and calcium for female students were the same or above the Recommended Dietary Allowances (RDA) for Koreans.

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A Study of variables Related to Nursing Productivity (간호생산성에 관한 연구: 관련변수의 검증을 중심으로)

  • 박광옥
    • Journal of Korean Academy of Nursing
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    • v.24 no.4
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    • pp.584-596
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    • 1994
  • The objective of the study is to explore the relationships between the variables of nursing productivity on the framework of system del in the tertiary university based care hospital in Korea. Productivity is basically defined as the relation-ship between inputs and outputs. Under the proposition that the nursing unit is a system that produces nursing care output using personal and material resources through the nursing intervention and nursing care management. And this major conception of nursing productivity system comproises input, process and output and feed-back. These categorized variables are essential parts to produce desirable and meaningful out-put. While nursing personnel from head nurse to staff nurses cooperate with each other, the head nurse directs her subordinates to achieve the goal of nursing care unit. In this procedure, the head nurse uses the leadership of authority and benevolence. Meantime nursing productivity will be greatly influenced by environment and surrounding organizational structures, and by also the operational objectives, the policy and standards of procedures. For the study of nursing productivity one sample hospital with 15 general nursing care units was selected. Research data were collected for 3 weeks from May 31 to June 20 in 1993. Input variables were measured in terms of both the served and the server. And patient classification scores were measured drily by degree of nursing care needs that indicated patent case-mix. And also nurses' educational period for profession and clinical experience and the score of nurses' personality were measured as producer input variables by the questionnaires. The process varialbes act necessarily on leading input resources and result in desirable nursing outputs. Thus the head nurse's leadership perceived by her followers is defined as process variable. The output variables were defined as length of stay, average nursing care hours per patient a day the score of quality of nursing care, the score of patient satisfaction, the score of nurse's job satis-faction. The nursing unit was the basis of analysis, and various statistical analyses were used : Reliability analysis(Cronbach's alpha) for 5 measurement tools and Pearson-correlation analysis, multiple regression analysis, and canonical correlation analysis for the test of the relationship among the variables. The results were as follows : 1. Significant positive relationship between the score of patient classification and length of stay was found(r=.6095, p.008). 2. Regression coefficient between the score of patient classification and length of stay was significant (β=.6245, p=.0128), and variance explained was 39%. 3. Significant positive relationship between nurses’ educational period and length of stay was found(r=-.4546, p=.044). 5. Regression coefficient between nurses' educational period and the score of quality of nursing care was significant (β=.5600, p=.029), and variance explained was 31.4%. 6. Significant positive relationship between the score of head nurse's leadership of authoritic characteristics and the length of stay was found (r=.5869, p=.011). 7. Significant negative relationship between the score of head nurse's leadership of benevolent characteristics and average nursing care hours was found(r=-.4578, p=.043). 8. Regression coefficient between the score of head nurse's leadership of benevolent characteristics and average nursing care hours was significant(β=-.6912, p=.0043), variance explained was 47.8%. 9. Significant positive relationship between the score of the head nurse's leadership of benevolent characteristics and the score of nurses' job satis-faction was found(r=.4499, p=050). 10. A significant canonical correlation was found between the group of the independent variables consisted of the score of the nurses' personality, the score of the head nurse's leadership of authoritic characteristics and the group of the dependent variables consisted of the length of stay, average nursing care hours(Rc²=.4771, p=.041). Through these results, the assumed relationships between input variables, process variable, output variables were partly supported. In addition it is also considered necessary that-further study on the relationships between nurses' personality and nurses' educational period, between nurses' clinical experience including skill level and output variables in many research samples should be made.

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