Communications for Statistical Applications and Methods
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v.30
no.3
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pp.331-341
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2023
Handling missing values in data analysis is essential in constructing a good prediction model. The easiest way to handle missing values is to use complete case data, but this can lead to information loss within the data and invalid conclusions in data analysis. Imputation is a technique that replaces missing data with alternative values obtained from information in a dataset. Conventional imputation methods include K-nearest-neighbor imputation and multiple imputations. Recent methods include missForest, missRanger, and mixgb ,all which use machine learning algorithms. This paper compares the imputation techniques for datasets with mixed datatypes in various situations, such as data size, missing ratios, and missing mechanisms. To evaluate the performance of each method in mixed datasets, we propose a new imputation performance measure (IPM) that is a unified measurement applicable to numerical and categorical variables. We believe this metric can help find the best imputation method. Finally, we summarize the comparison results with imputation performances and computational times.
Purpose: The paper contributes to the existing literature on Vietnamese corporate governance and firm performance with a focus on listed family firms and the use of a more suitable econometric framework to analyze firm performance. The study investigates how family firm performance is affected by corporate governance under the standpoint of stewardship theory in Vietnam. Research design, data and methodology: With the use of different measures for firm performance (Tobin's Q, ROA, and ROE), regression models were estimated using Generalized Least Square (GLS) method on a panel data of a total of 113 listed companies during the five-year period from 2015 to 2019. Results: We found that family ownership as the main characteristic of the stewardship theory affects family firms positively. In addition, several other characteristics in corporate governance as board composition (board independence, board audits, and board committees), CEO (age and tenure) and firm characteristics (size, age, expansion, and annual sales) showed significant impacts on firm performance. Our findings also suggest that family firm performance can be either positively or negatively affected based on the characteristics of corporate governance. The findings can help companies evaluate the significance of corporate governance through deciding board structure and the selection of CEOs to match family firm characteristics. It also gives insights for investors, rating agencies, and policymakers for relevant purposes.
Lee, Seog-Jun;Park, Sung-Sik;Hahm, Yukeun;Gustafson, D.
The Journal of Information Systems
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v.22
no.2
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pp.105-129
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2013
Recently, since the interest with well-being has been getting higher than ever, people want reliable source of information related with health and medical treatment. Because of the characteristics of information related with medical care, there have been difficulties to find the information from books, television and internet surfing, for treating disease. Misinformation that can be obtained when considering dangerous situations or side effects, the role of the e-Health system is becoming more important. The objective of this study is an analysis of correlation and effect among patient's information need, e-Health system use and system outcome. To achieve the object of this study, e-Health system had been given to patients of breast cancer in Wisconsin and Detroit for 16 weeks. As a result, 282 sample was gathered and modified to meet purpose of the study. As a result, the information needs of patients due to the performance of the e-Health systems and shown to affect even the perception of patients' emotional and physical health and social support.
Kim Gap Tae;Park Gi Nam;Lee Dong Cheol;Gang Yu Jeong
Proceedings of the Korea Association of Information Systems Conference
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2004.11a
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pp.339-348
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2004
There were few empirical researches on the ERP system in spite of increasing interest on ERP system recently Therefore, the purpose of this study is to develop an framework for the marketing performance based on evaluation of ERP system used by the theoretical model for evaluation of information system and the empirical data of Korean firms. This study was empirically examined an effect of ERP system and its information quality on the use of information from ERP system. And another effect of information use from ERP system on marketing performances survey on MIS was conducted for the marketing strategy. In this study, the structural equation model was established for verifying the relationship of above variables. And several hypotheses were established and examined empirically from that structural equation model. In conclusion, the effectiveness of ERP system must be evaluated within structural relationship among ERP system and its information quality, the use of information from ERP, and marketing performances. Additionally, the result of this research has founded the fact that ERP system and its information quality are important as elements of successful ERP system.
This paper describes a new approach to Internet host mobility. We argue that local mobility, the performance of existing mobile host protocol can be significantly improved. It proposes Fast Moving Detection scheme that based on neighbor AP channel information and moving detection table. And, it composes Local Area Clustering Path (LACP) domain that collected in AP's channel information and MN interface information. It stored the roaming table to include channel information and moving detection. Those which use the proposal scheme will need to put LACP information into the beacon or probe frame. Each AP uses scheme to inform available channel information to MN. From the simulation result, we show that the proposed scheme is advantageous over the legacy schemes in terms of the burst blocking probability and the link utilization.
Journal of The Institute of Information and Telecommunication Facilities Engineering
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v.3
no.2
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pp.42-50
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2004
This paper describes a new approach to Internet host mobility. We argue that local mobility, the performance of existing mobile host protocol can be significantly improved. It proposes Fast Moving Detection schemethat based on neighbor AP channel information and moving detection table. And, it composes Local Area Clustering Path (LACP) domain that collected in AP's channel information and MN interface information. It stored the roaming table to include channel information and moving detection. Those which use the proposal scheme will need to put LACP information into the beacon or probe frame. Each AP uses scheme to inform available channel information to MN. From the simulation result, we show that the proposed scheme is advantageous over the legacy schemes in terms of theburst blocking probability and the link utilization.
Journal of the Korean Society for Library and Information Science
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v.18
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pp.55-98
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1990
This research attempts to verify the hypothesis that the workers in the small-and medium-sized industries use more informal information channels than formal ones do to get the information necessary to industrial activities. Information sources are divided by the internal and the external ones and these are sub-divided by their acquiring channels, publishers and holding institutions. It is intended to investigate the information sources according to the use frequency, age, origin and format of documents used. The degree of benefit to the workers in their practical work through the use of information sources and the use frequency of information sources by the department and years of experience are also investigated. The data to test the hypothesis was collected through the questionnaires distributed to the workers in 300 sampled firms from June 5 to June 20, The following facts have been verified as the result : 1. Workers in industries acquire information mainly through the contacts with the colleagues or superiors in their departments, and the junior workers depend more on the colleague and superiors than senior workers are. 2. Among the documents published internally, the ones from the research and development departments are mostly used. The documents issued by the worker's own departments are also frequently used and the senior workers, the more frequently use the internal publications than the junior workers do. 3. Among the internal documents stored in various places in the industries, the documents kept in the worker's own departments are used most frequently. The senior workers the more use privately owned documents than the junior workers do. 4. As far as the external channels are concerned, information is obtained mainly through suppliers of equipment and raw materials and the use frequency of information channels varies according to department. The senior workers the more receive information through supporting institution, seminar and exhibition than the junior workers do. 5. Among the external publication, the ones published by the industrial supporting institutions are heavily used and the workers in research and developments frequently use the external publications. 6. The documents held in governmental industrial institutions and industrial supporting institutions are heavily used compared with the ones stored in other external institutions. The holding places of frequently used documents vary according to the working departments. 7. The degree of benefit to practical work performance resulted from the internal information use is less than by the use of external information. 8. The documents published more than five years ago are more used than the ones of less than five years, Korean and Japanese documents are used frequently and catalogues, patents and standards are used to a great extent. The documents are used differently in accordance with work departments.
Journal of Korean Society of Industrial and Systems Engineering
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v.39
no.3
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pp.192-203
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2016
Uganda is a country blessed with the biggest number of mountain Gorillas in the whole world. These animals contribute at least 12% in revenue generation to the Tourism sector through tracking by both local and foreign tourists who pay for the tracking permits. However, Gorilla tracking is also a big challenge even in the presence of highly skilled and well-trained game rangers. Development and implementation of a secure Computer and Mobile based Gorilla Tracking (GT) system that uses GIS and GPS technologies would be the most ideal technology to use. Therefore, this study aimed to find out the critical factors that would affect the Behavioral Intention of the would-be users to successfully decide to use such GIS/GPS-GT system. We used the existing UTAUT model to integrate six factors such as Performance Expectancy, Effort Expectancy, Employee Peer Influence, Facilitating Conditions, Behavioral Intention and System Use. However, Infrastructure Availability and Non-Technical Facilitating Conditions were added to reflect Ugandan ICT context. This amended UTAUT model was used to carry out the survey. The questionnaire was emailed to 220 government employees in the fields of ICT, Tour and Travel, Environmental Groups officials and Farmers who garden near the game reserves. A total of 133 were obtained fully completed, whereas 127 were deemed usable thus yielding a response rate of 58%. The analysis results show that except for non-technical facilitating conditions, effort expectancy, peer influence, performance expectancy and infrastructure availability positively affects behavioral Intention to use GIS/GPS-GT. This indicates that people in Uganda don't bother about regulations and rules in regard to using information system. As long as the system does what they want it to, anything else does not matter. As an employee in an organization is told to use a system by their supervisor, they have no objection to otherwise they risk losing their job. This implies that, supervisors have a great responsibility in the process of developing, implementing and using the system in Uganda.
Purpose The main purpose of this study is to examine whether the expectations and outcomes of the bicycle-sharing service significantly influence users' expectation disconfirmation, satisfaction, and continuous intention to use. In addition, we will verify the moderating effect of social interaction in bicycle-sharing service on the relationship between satisfaction and continuous intention to use. Design/methodology/approach Based on previous studies dealing with determinants of bicycle use, users' expectations and outcomes of the bicycle-sharing service were measured by three variables; accessibility, convenience, and safety. To collect the data, we conducted a survey of undergraduates at a university located in Seoul for three weeks, beginning March 6. Participants completed the first questionnaire, which measured expectations of the bicycle-sharing service based on the attributes and social interaction before using the BSS. After a few weeks, the same participants completed the second questionnaire, which measured outcomes of the outcome, disconfirmation, satisfaction, and continuous intention to use the BSS. Only participants who completed both surveys received monetary compensation. In order to test hypothesis, the Smart Partial Least Square (SmartPLS) modeling technique was applied. Findings In terms of main effects, based on the expectation disconfirmation theory, the results indicated that there were significant relationship among expectation, performance, disconfirmation, and satisfaction. In particular, it was verified that disconfirmation completely plays a mediating role between performance and satisfaction. In addition, the moderating effect of social interaction was examined. There was a significant interaction effects of social interaction and satisfaction on the continuous intention to use for leisure purpose. Finally, this study is expected to contribute to the study of resource sharing in the field of tourism and provide baseline information for future research.
Purpose - The purpose of this study is to explore the possibility of predicting the degree of smartphone overdependence based on mobile phone usage patterns. Design/methodology/approach - In this study, a survey conducted by Korea Internet and Security Agency(KISA) called "problematic smartphone use survey" was analyzed. The survey consists of 180 questions, and data were collected from 29,712 participants. Based on the data on the smartphone usage pattern obtained through the questionnaire, the smartphone addiction level was predicted using machine learning techniques. k-NN, gradient boosting, XGBoost, CatBoost, AdaBoost and random forest algorithms were employed. Findings - First, while various factors together influence the smartphone overdependence level, the results show that all machine learning techniques perform well to predict the smartphone overdependence level. Especially, we focus on the features which can be obtained from the smartphone log data (without psychological factors). It means that our results can be a basis for diagnostic programs to detect problematic smartphone use. Second, the results show that information on users' age, marriage and smartphone usage patterns can be used as predictors to determine whether users are addicted to smartphones. Other demographic characteristics such as sex or region did not appear to significantly affect smartphone overdependence levels. Research implications or Originality - While there are some studies that predict smartphone overdependence level using machine learning techniques, but the studies only present algorithm performance based on survey data. In this study, based on the information gain measure, questions that have more influence on the smartphone overdependence level are presented, and the performance of algorithms according to the questions is compared. Through the results of this study, it is shown that smartphone overdependence level can be predicted with less information if questions about smartphone use are given appropriately.
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