• Title/Summary/Keyword: DID model

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Comparative Study of Various Machine-learning Features for Tweets Sentiment Classification (트윗 감정 분류를 위한 다양한 기계학습 자질에 대한 비교 연구)

  • Hong, Cho-Hee;Kim, Hark-Soo
    • The Journal of the Korea Contents Association
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    • v.12 no.12
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    • pp.471-478
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    • 2012
  • Various studies on sentiment classification of documents have been performed. Recently, they have been applied to twitter sentiment classification. However, they did not show good performances because they did not consider the characteristics of tweets such as tweet structure, emoticons, spelling errors, and newly-coined words. In this paper, we perform experiments on various input features (emoticon polarity, retweet polarity, author polarity, and replacement words) which affect twitter sentiment classification model based on machine-learning techniques. In the experiments with a sentiment classification model based on a support vector machine, we found that the emoticon polarity features and the author polarity features can contribute to improve the performance of a twitter sentiment classification model. Then, we found that the retweet polarity features and the replacement words features do not affect the performance of a twitter sentiment classification model contrary to our expectations.

Determination of Energy and Nutrient Utilization of Enzyme-treated Rump Round Meat and Lotus Root Designed for Senior People with Young and Age d Hens as an Animal Model

  • Park, Okrim;Kim, Jong Woong;Lee, Hong-Jin;Kil, Dong Yong;Auh, Joong-Hyuck
    • Food Science of Animal Resources
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    • v.36 no.1
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    • pp.109-113
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    • 2016
  • This study aimed to examine the nutrient utilization of rump round meat and lotus root using young (32 wk) and aged hens (108 wk) as an animal model. Rump round meat and lotus root were prepared with or without enzymatic treatment. For each age group of laying hens, a total of 24 Hy-Line Brown laying hens were randomly allotted to one of two dietary treatments with six replicates. For rump round meat, the true total tract retention rate (TTTR) of dry matter (DM) and nitrogen (N) were unaffected by either enzymatic treatment or hen age. However, aged hens had greater (p<0.01) TTTR of energy and crude fat than young hens. Enzymatic treatment did not influence the TTTR of energy or crude fat. In addition, we did not observe any significant interaction between the TTTR of DM, energy, N, or crude fat in rump round meat and hen age or enzymatic treatment. The TTTR of DM remained unchanged between controls and enzyme-treated lotus root for young hens. However, enzyme-treated lotus root exhibited greater (p<0.05) TTTR of DM than control lotus root for aged hens, resulting in a significant interaction (p<0.05). The TTTR of energy and N in lotus roots were greater (p<0.01) for aged hens than for young hens. In conclusion, enzymatic treatment exerted beneficial effects on energy and nutrient utilization in aged hens, suggesting the aged hen model is practical for simulation of metabolism of elderly individuals.

Elemental analysis of caries-affected root dentin and artificially demineralized dentin

  • Sung, Young-Hye;Son, Ho-Hyun;Yi, Keewook;Chang, Juhea
    • Restorative Dentistry and Endodontics
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    • v.41 no.4
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    • pp.255-261
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    • 2016
  • Objectives: This study aimed to analyze the mineral composition of naturally- and artificially-produced caries-affected root dentin and to determine the elemental incorporation of resin-modified glass ionomer (RMGI) into the demineralized dentin. Materials and Methods: Box-formed cavities were prepared on buccal and lingual root surfaces of sound human premolars (n = 15). One cavity was exposed to a microbial caries model using a strain of Streptococcus mutans. The other cavity was subjected to a chemical model under pH cycling. Premolars and molars with root surface caries were used as a natural caries model (n = 15). Outer caries lesion was removed using a carbide bur and a hand excavator under a dyeing technique and restored with RMGI (FujiII LC, GC Corp.). The weight percentages of calcium (Ca), phosphate (P), and strontium (Sr) and the widths of demineralized dentin were determined by electron probe microanalysis and compared among the groups using ANOVA and Tukey test (p < 0.05). Results: There was a pattern of demineralization in all models, as visualized with scanning electron microscopy. Artificial models induced greater losses of Ca and P and larger widths of demineralized dentin than did a natural caries model (p < 0.05). Sr was diffused into the demineralized dentin layer from RMGI. Conclusions: Both microbial and chemical caries models produced similar patterns of mineral composition on the caries-affected dentin. However, the artificial lesions had a relatively larger extent of demineralization than did the natural lesions. RMGI was incorporated into the superficial layer of the caries-affected dentin.

The Impact of Perceived Risks and Switching Costs on Switching Intention to Cloud Services: Based on PPM Model (지각된 위험과 전환비용이 클라우드 서비스로의 전환의도에 미치는 영향에 관한 연구: PPM 모델 중심으로)

  • Lee, Seung Hee;Jeong, Seok Chan
    • The Journal of Information Systems
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    • v.30 no.3
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    • pp.65-91
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    • 2021
  • Purpose In this study, we investigated the impact of perceived risk and switching costs on switching intention to cloud service based on PPM (Pull-Push-Mooring) model. Design/methodology/approach We focused on revealing the switching factors of the switching intention to the cloud services. The switching factors to the cloud services were defined as perceived risk consisting of performance risk, economic risk, and security risk, and switching costs consisting of financial and learning costs. On the PPM model, we defined the pull factors consisting of perceived usefulness and perceived ease of use, and the push factor as satisfaction of the legacy system, and the mooring factor as policy supports. Findings The results of this study as follows; (1) Among the perceived risk factors, performance risk has a negative effect on the ease of use of pull factors, and finally it was found to affect the switching intention to the cloud services. Therefore, cloud service providers need to improve trust in cloud services, service timeliness, and linkage to the legacy systems. And it was found that economic risk and security risk among the perceived risk factors did not affect the switching intention to the cloud services. (2) Of the perceived risk factors, financial cost and learning cost did not affect the satisfaction of the legacy system, which is a push factor. It indicates that the respondents are positively considering switching to cloud service in the future, despite the fact that the respondents are satisfied with the use of the legacy system and are aware of the switching cost to cloud service. (3) Policy support was found to improve the switching intention to cloud services by alleviating the financial and learning costs required for cloud service switching.

Factors related to the intention of healthy eating behaviors based on the theory of planned behavior: focused on adults residing in Beijing, China

  • Liu, Dan;Lee, Seungwoo;Hwang, Ji-Yun
    • Journal of Nutrition and Health
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    • v.54 no.1
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    • pp.67-75
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    • 2021
  • Purpose: The theory of planned behavior (TPB) was used to investigate how the psychological constructs of attitude, subjective norms, and perceived behavioral control (PBC) affect the individual intention of behaviors in adults. Social support is also important in enabling the stability of healthy eating. This study examined the relationship between three major constructs of TPB as well as social support and the intention of healthy dietary behaviors in adults residing in Beijing, China using the extended TPB. Methods: The study questionnaire was based on previously validated items and an online survey was conducted from October to November 2020. Using a total of 244 Chinese adults in Beijing, multiple linear regression analysis was used to test the relationships between three major constructs of TPB as well as the social support and intention of healthy eating. Results: Among the three major constructs of TPB, subjective norms (p = 0.044) and PBC (p = 0.000) were significantly related to the behavioral intention of healthy eating (p = 0.000), and the model explained 76.6% of the variance of the behavioral intention from the three constructs of TPB included in the multiple linear regression model. The additional inclusion of social support to the model did not increase the explanatory power of the model to describe the behavioral intention of healthy eating. The subjective norms (p = 0.040) and PBC (p = 0.000) were still significant where social support did not explain the variance of the behavioral intention adequately. Conclusion: The subjective norms and PBC may be potential determinants of the behavioral intention of healthy eating in adults residing in Beijing, China. These study results can be used to promote healthy eating in Chinese adults living in urban areas. Large-scale intervention studies will be needed to determine if social norms and PBC predict the actual behaviors of healthy eating in Chinese adults.

An Integrative Approach for Strengthening Continual Adoption of e-Government Services : An Empirical Study (전자정부 서비스의 지속적 수용 강화를 위한 통합적 접근 : 실증연구)

  • Lim, Se Hun
    • Journal of Information Technology Applications and Management
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    • v.20 no.1
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    • pp.19-41
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    • 2013
  • This study analyzed the users acceptance of e-Government services. Many IT(Information Technology) adoption studies appeared the TAM(technology adoption model) of Davis[1989] as a theoretical background. The TAM composed of three factors those are the perceived easy of use, the perceived usefulness, and intention to adoption of IT. However, TAM did not explain the consequences of intention to adoption and antecedents of the ease of use and usefulness in IT adoption. To overcome limitations of TAM, many technology acceptance studies done. In this study, the researcher suggested the IT acceptance model for explaining users adoption of e-Government service based on the model of IT acceptance of Wixom and Todd[2005]. The model of Wixom and Todd[2005] based on the TAM of Davis[1989], IT adoption model of Taylor and Todd[1995] and, IS(Information Systems) success model of Delone and Mclean[1992, 2003]. For testing our research model, the researcher collected data from 200 users of e-Government services. The researcher analyzed in measurement model and structural model using statistical software. This study analyzed relationships among interaction, information quality, Web systems quality, satisfaction, ease of use, usefulness, and attitude to explain and predict influences of the users acceptance of e-Government services. The results of this study will provide useful information about develop a strategy for usage spread of e-Government services.

A standardization model based on image recognition for performance evaluation of an oral scanner

  • Seo, Sang-Wan;Lee, Wan-Sun;Byun, Jae-Young;Lee, Kyu-Bok
    • The Journal of Advanced Prosthodontics
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    • v.9 no.6
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    • pp.409-415
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    • 2017
  • PURPOSE. Accurate information is essential in dentistry. The image information of missing teeth is used in optically based medical equipment in prosthodontic treatment. To evaluate oral scanners, the standardized model was examined from cases of image recognition errors of linear discriminant analysis (LDA), and a model that combines the variables with reference to ISO 12836:2015 was designed. MATERIALS AND METHODS. The basic model was fabricated by applying 4 factors to the tooth profile (chamfer, groove, curve, and square) and the bottom surface. Photo-type and video-type scanners were used to analyze 3D images after image capture. The scans were performed several times according to the prescribed sequence to distinguish the model from the one that did not form, and the results confirmed it to be the best. RESULTS. In the case of the initial basic model, a 3D shape could not be obtained by scanning even if several shots were taken. Subsequently, the recognition rate of the image was improved with every variable factor, and the difference depends on the tooth profile and the pattern of the floor surface. CONCLUSION. Based on the recognition error of the LDA, the recognition rate decreases when the model has a similar pattern. Therefore, to obtain the accurate 3D data, the difference of each class needs to be provided when developing a standardized model.

Changes in the Clothing Expenditure using Difference in Difference Model: Comparison between Korean and U.S. Households (이중차이 모형을 적용한 1990년대 중반 이후 한국과 미국소비자의 피복비 지출 변화 분석 및 비교)

  • Lee, Mi-Young
    • Korean Journal of Human Ecology
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    • v.21 no.2
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    • pp.349-362
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    • 2012
  • This paper explores differences demonstrated by changes of consumers' clothing expenditure in Korea and the United States since the mid-1990s. Evidence for this study was extrapolated from annual data provided by the Household Expenditure Survey, which was carried out in Korea between 1996 and 2008, and the Consumer Expenditure Survey, which was carried out in the United States during the same time period. The results include: (1) The proportion of the clothing expenditure decreased during the subject period in both Korea and the United States; (2) The decrease in proportional clothing expenditure was greater in Korea than in the United States; (3) Although the relative prices of clothes decreased greatly during this period in both countries, it was determined that the decrease in clothing prices in the United States was greater when compared to those in Korea; and (4) By using the DID(Difference in difference) model, the author contends that a decrease in clothing purchases contributed to the decrease of prices for clothing in the United States, while in Korea, the decrease in prices for clothing was also impacted by other factors including changes in household expenditures for education and communication.

Strength prediction of rotary brace damper using MLR and MARS

  • Mansouri, I.;Safa, M.;Ibrahim, Z.;Kisi, O.;Tahir, M.M.;Baharom, S.;Azimi, M.
    • Structural Engineering and Mechanics
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    • v.60 no.3
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    • pp.471-488
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    • 2016
  • This study predicts the strength of rotary brace damper by analyzing a new set of probabilistic models using the usual method of multiple linear regressions (MLR) and advanced machine-learning methods of multivariate adaptive regression splines (MARS), Rotary brace damper can be easily assembled with high energy-dissipation capability. To investigate the behavior of this damper in structures, a steel frame is modeled with this device subjected to monotonic and cyclic loading. Several response parameters are considered, and the performance of damper in reducing each response is evaluated. MLR and MARS methods were used to predict the strength of this damper. Displacement was determined to be the most effective parameter of damper strength, whereas the thickness did not exhibit any effect. Adding thickness parameter as inputs to MARS and MLR models did not increase the accuracies of the models in predicting the strength of this damper. The MARS model with a root mean square error (RMSE) of 0.127 and mean absolute error (MAE) of 0.090 performed better than the MLR model with an RMSE of 0.221 and MAE of 0.181.

Applicability Investigation for the Odor Source Tracking Approach using the Wind Field and the Fingerprinting (바람장 및 Fingerprint를 이용한 악취추적기법 활용가능성 평가)

  • Na, Kyung-Ho;Bak, Yong-Chul;Jang, Young-Gi
    • Journal of Korean Society for Atmospheric Environment
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    • v.23 no.1
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    • pp.1-13
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    • 2007
  • This study was carried out to evaluate the applicability of the odor source tracking using wind field and fingerprint as a solution tool. First of all, CALMET and HYSPLIT modeling system, and database of odor discharge companies were utilized to track odor from industrial complexes. Secondly, industrial odor fingerprint was made by listing on the 19 domestic industries, and compared with foreign data to assess the representative, and thus the similarity was 86.7%. On the modeling experiment, Sihwa industrial complex did not show any difference because the matching rates of day and night were 49.5% and 50.0%, respectively. However, the Banwol and Sihwa industrial complexes did show some differences due to odor facility density. Separately, in this study, odor samples were obtained from 10 odor discharging companies, located in the Sihwa and Banwol industrial complexes, They were compared with the results of odor tracking modeling. The matched companies were 4 of 10 by three cases of tracking, while the fingerprint and industry of odor monitoring networks and companies matched each other. Therefore, this study confirmed the approach applicability of source tracking system using the fingerprint.