• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.4C
• /
• pp.451-457
• /
• 2006

A peer-to-peer(P2P) network is inherently vulnerable to malicious attacks from participating peers because of its open, flat, and autonomous nature. This paper addresses the problem of effectively defending from active attacks of malicious peers at bootstrapping phase and at online phase, respectively. We propose a secure membership handling protocol to protect the assignment of ID related things to a newly joining peer with the aid of a trusted entity in the network. The trusted entities are only consulted when new peers are joining and are otherwise uninvolved in the actions of the P2P networks. For the attacks in online phase, we present a novel message structure applied to each message transmitted on the P2P overlay. It facilitates the detection of message alteration, replay attack and a message with wrong information. Taken together, the proposed techniques deter malicious peers from cheating and encourage good peers to obey the protocol of the network. The techniques assume a basic P2P overlay network model, which is generic enough to encompass a large class of well-known P2P networks, either unstructured or not.

• Journal of Digital Convergence
• /
• v.14 no.9
• /
• pp.111-121
• /
• 2016

This study provides an approach to perform the double mediation analysis in structural equation models using the R. For this purpose, the study reviews a variety of techniques for mediation analysis, selects the bootstrapping technique as the most suitable way for performing the double mediation analysis and develops an approach for the double mediation analysis in structural equating models with the bootstrapping using the plspm which is the R package for the performing PLS path analysis. This study will be useful for the studies including the double mediation analysis in structural equation modeling, which is not supported by most of SEM packages, also will provide the knowledge base for in-depth analysis through suggesting the new mediation analysis technique using R for the researchers.

• Journal of KIISE:Software and Applications
• /
• v.35 no.5
• /
• pp.325-334
• /
• 2008

The goal of text categorization is to classify documents into a certain number of pre-defined categories. The previous studies in this area have used a large number of labeled training documents for supervised learning. One problem is that it is difficult to create the labeled training documents. While it is easy to collect the unlabeled documents, it is not so easy to manually categorize them for creating training documents. In this paper, we propose a new text categorization method based on semi-supervised learning. The proposed method uses only unlabeled documents and keywords of each category, and it automatically constructs training data from them. Then a text classifier learns with them and classifies text documents. The proposed method shows a similar degree of performance, compared with the traditional supervised teaming methods. Therefore, this method can be used in the areas where low-cost text categorization is needed. It can also be used for creating labeled training documents.

• Journal of the Korean Applied Science and Technology
• /
• v.40 no.6
• /
• pp.1213-1224
• /
• 2023

The purpose of this study was to analyze the mediating role of self-efficacy in the relationship between the behavioral routines of beauty service workers on service performance and work performance. The subjects of the study were 311 beauty consumers in Seoul and Gyeonggi, and data were collected and analyzed using a structured questionnaire. For data analysis, descriptive statistics, confirmatory factor analysis(CFA), correlation analysis, structural equation model analysis(SEM), and mediating effect analysis using bootstrapping techniques were conducted. The conclusions drawn through a series of research procedures are as follows. First, the behavioral routines of beauty service workers were found to have a statistically significant positive(+) effect on self-efficacy, service performance, and work performance. Second, the self-efficacy of beauty service workers was found to have a statistically significant positive (+) effect on service performance and work performance. Third, the partial mediating effect of self-efficacy was shown in the relationship between beauty service workers' behavioral routines, service performance, and work performance.

• Journal of Korean Institute of Industrial Engineers
• /
• v.42 no.4
• /
• pp.263-269
• /
• 2016

The purpose of this study is to challenge a computational regression-type problem, that is handling large-size data, in which conventional metamodeling techniques often fail in a practical sense. To solve such problems, regression-type boosting, one of ensemble model techniques, together with bootstrapping-based re-sampling is a reasonable choice. This study suggests weight updates by the amount of the residual itself and a new error decision criterion which constructs an ensemble model of models selectively chosen by rejection limits. Through these ideas, we propose AdaBoost.RMU.R as a metamodeling technique suitable for handling large-size data. To assess the performance of the proposed method in comparison to some existing methods, we used 6 mathematical problems. For each problem, we computed the average and the standard deviation of residuals between real response values and predicted response values. Results revealed that the average and the standard deviation of AdaBoost.RMU.R were improved than those of other algorithms.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.283-287
• /
• 2010

Stochastic simulation of hydrologic data has been widely developed for several decades. However, despite the several advances made in literature still a number of limitations and problems remain. In the current study, some stochastic simulation approaches tackling some of the existing problems are discussed. The presented models are based on nonparametric techniques such as block bootstrapping, and K-nearest neighbor resampling (KNNR), and kernel density estimate (KDE). Three different types of the presented stochastic simulation models are (1) Pilot Gamma Kernel estimate with KNNR (a single site case) and (2) Enhanced Nonparametric Disaggregation with Genetic Algorithm (a disaggregation case). We applied these models to one of the most challenging and critical river basins in USA, the Colorado River. These models are embedded into the hydrological software package, Pros and cons of the models compared with existing models are presented through basic statistics and drought and storage-related statistics.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.12
• /
• pp.473-484
• /
• 2021

This study aims to examine the role of training and absorptive capacity as a mediator to examine the impact of human capital dimensions on the performance of an organization. This study employs the quantitative approach for analysis. A sample of 208 respondents was collected from the textile factories based in Karachi and Faisalabad. Data was analyzed using the PLS-SEM technique. PLS-SEM algorithm was used to check the validity and reliability of the data. PLS-SEM bootstrapping was used for studying the impact. The results show that the skills have an insignificant impact on organizational performance. Education and skills have an insignificant indirect impact on the performance of an organization. The research findings show that the human capital dimensions are full and partially mediated via absorptive capacity and training. The findings revealed that if we implement one by one dimension of human capital then it will not cause any increase in the organization's performance but if we implement all dimensions then it results in optimal performance. Thus, this study suggests adopting effective training techniques and creating absorptive capacity in an organization to increase the performance of an organization. The findings of this study significantly contribute to the existing body of knowledge.

• The Journal of Asian Finance, Economics and Business
• /
• v.8 no.8
• /
• pp.387-397
• /
• 2021

The object of this article is to assess the factors affecting the behavioral intention of young retail customers to use digital banking services in Vietnam. In this article, multivariate data analysis techniques including Cronbach's Alpha, Exploratory factor analysis (EFA), Confirmatory factor analysis (CFA), Structure equation model (SEM), and Bootstrapping are used to analyze the data collected from 525 young respondents under the age of 35 who are using or having opportunities to experience digital banking services. The people taking part in the survey were mainly University students with incomes of most of them under VND 5 million. The result from the analysis illustrates that (1) perceived ease of use positively affects intention to use, (2) social influence positively impacts intention to use, and (3) customer support has a positive impact on the intention of young people to use digital banking services. While technology self-efficacy, convenience, and perceived security were found to have an impact on intention to use services in former studies, the influences of these factors on intention to use digital banking services are found insignificant in this research. From these results, the author provides implications for commercial banks to increase the intention to use digital banking of young people in Vietnam.

• Journal of Industrial Convergence
• /
• v.22 no.5
• /
• pp.79-88
• /
• 2024

The study aim was to investigate the relationship between adolescents' physical activity and subjective health perceptions and determine whether body mass index (BMI), an obesity-related indicator, had a mediating or moderating effect on this relationship. To achieve the purpose of this study, raw data from the 18th Youth Health Behavior Online Survey (2022) were used, and data from 23,612 people were ultimately selected for the research analysis. A confirmatory factor analysis and structural equation modeling were applied to the data, and bootstrapping techniques were used to verify the mediating effect. To verify the moderating effect, a multigroup analysis of the structural equation model was applied to calculate pairwise parameter comparison values. All statistical significance levels were set at .05. The results of this study follow. First, the greater the amount of physical activity among adolescents, the more positive was the effect on subjective health perception. Second, subjective body type perception had a partial mediating effect on the relationship between physical activity and subjective health perception. Third, subjective body type had a moderating effect on physical activity and subjective health perception. Specifically, people who perceived their subjective body types as average viewed their subjective health more positively when they engaged in more physical activity than those who perceived their body types as slightly or very overweight. In conclusion, preventing obesity and positively changing the subjective health status through sufficient physical activity during adolescence are important.

• The Journal of The Korea Institute of Intelligent Transport Systems
• /
• v.23 no.3
• /
• pp.1-16
• /
• 2024

In the present highway design guidelines suggest that the capacity of one-lane hi-pass lanes is 2,000 veh/h for mainline toll plaza and 1,700 veh/h for interchange toll plaza. However, in a study conducted in early 2010, capacity of the mainline toll plaza was presented with 1,476 veh/h/ln to 1,665 veh/h/ln, and capacity of the interchange toll plaza was presented as 1,443 veh/h/ln. Accordingly, this study examined the feasibility of the capacity of the currently proposed highway one-lane hi-pass lane. Based on the 2021 individual vehicle passing data collected from the one-lane hi-pass gantry, the speed-traffic volume relationship graph and headway were used to calculate and compare capacity. In addition, the bootstrapping technique was introduced to utilize the headway and new processing methods for collected data were reviewed. As a result of the analysis, the one-lane hi-pass capacity could be estimated at 1,700 veh/h/ln for the interchange toll plaza, and at least 1,700 veh/h/ln for the mainline toll plaza. In addition, by using the bootstrap technique when using headway data, it was possible to present an estimated capacity similar to the observed capacity.