• The KIPS Transactions:PartC
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• v.16C no.1
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• pp.57-64
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• 2009

In order to efficiently provide IP based Wireless Broadband services in Mobile WiMAX, schemes for more efficiently utilizing a limited bandwidth in radio links are needed. Robust Header Compression (ROHC), a standard header compression scheme proposed by IETF, Bi-directional Optimistic (O) mode provides higher compression efficiency and robustness compared with Payload Header Suppression (PHS) which is an optional header compression scheme for mobile WiMAX [1, 2]. However, if consecutive packet losses occur because of a Shadow Region of Mobile WiMAX or bit errors, header decompression failure rate of the ROHC O mode increases due to inconsistency of the compression information between the Compressor and the Decompressor. Therefore, a complementary mechanism is needed. In this paper, we propose an approach for the dynamic adjustment of an optimistic parameter, which has an effect on both the compression efficiency and the robustness, for improving the performance of ROHC O mode. We also analyze the performance of the proposed approach using an OPNET simulator.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.141-155
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• 2016

This research is a descriptive study that aimed to identify the health knowledge and optimistic bias related to stroke of middle-aged adults and the effect these had on their health-promoting lifestyle. The research was conducted from July 15 to August 15, 2015. The research subjects were 191 adults aged between 40 to 60 years. A structured questionnaire was used and self-administered for data collection. The PASW Statistics 21.0 and AMOS 21.0 programs were used for data analysis, and analysis of variance, correlation analysis, and structural equation modeling analysis were conducted. It was found that the middle-aged adults recognized smoking and hypertension as higher risk factors for stroke than diabetes, and there was a slight optimistic bias for stroke. Health knowledge about stroke had correlations with optimistic bias (r = -.143, p = .048) and health-promoting lifestyle (r = .268, p = < .001), while optimistic bias had correlations with interpersonal relationships and stress (r = .177, p = .014) in health-promoting lifestyle. In addition, health-promoting lifestyle affected health knowledge more than optimistic bias. In conclusion, it was found that the active information acquisition, health knowledge, and optimistic bias of middle-aged adults toward stroke were important factors pertaining to a stroke-related health-promoting lifestyle. Therefore, an education program to improve the health-promoting lifestyle related to stroke in middle-aged adults should be considered as a way to enhance stroke-related health knowledge and reduce optimistic bias.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.26 no.2
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• pp.475-487
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• 2016

Recently, various risks of smartphone hacking are emerging. Smishing crime techniques become more cunning and its damage has been increasing, thereby requiring effective ways of preventing and coping with smishing. Especially, it is emphasized the need for smartphone users' security awareness and training besides technological approach. This study investigates the effective method for providing news messages in order to improve the perception of risk from smishing. This research empirically examines that the degree of optimistic bias on risk perception can vary depending on news frame, topic type, and involvement regarding smishing. Based on the findings, it identifies the factors influencing risk perception and verifies effective ways of promoting individual security awareness on smishing. The results of this study provide implications that assist in educating, campaigning and promoting information security awareness for smart device users.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.21-26
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• 2010

Recently, since the prevalence of electric driving transfer system arouse the electric corrosion of neighboring underground metal establishment, the problems caused by that kind of electric corrosion became very serious. In this paper, we studied about a theoretical concept and concrete concepts of electric corrosion and tried suggested an optimistic chemico-electrical measures on the electric corrosion of underground metal establishments.

• Journal of Digital Convergence
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• v.20 no.1
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• pp.349-359
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• 2022

This research is a descriptive study that aimed to identify the health knowledge related stroke, optimistic bias, and social support of middle-aged adults and the effect these had on their health-promoting lifestyle This study was conducted by collecting 220 adults aged between 40 to 60 years from C City D city and K city. Data were analyzed using descriptive analysis, ANOVA, t-test, Pearson's correlation coefficients and multiple regression with the SPSS 23.0 program. The average health-promoting lifestyle was 44.27 points. The health-promoting lifestyle of the study participants showed a positive correlation between the optimistic bias(r=.18, p=.001) and social support(r= .61, p<.000). According to the results of multiple regression analysis, perception of Necessity for Stroke Education(β=.12, p=.010), optimistic bias(β=.18, p=.040), and social support(β=.48, p<.000) were shown to be significant factors that affected the health-promoting lifestyle of the participants. These variables explained 38.5%. Therefore, an health education program to improve the health-promoting lifestyle related to stroke in adults should be considered as a way to enhance social support and reduce optimistic bias.

• Journal of the Korea Construction Safety Engineering Association
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• s.51
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• pp.93-105
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• 2010

The object of this study is to understand the psychological factor of the worker on safety and recommend experimental factor of safety education program. The following are the methods of this study. We analyzed the statistical data from survey to workers(N=139) about the psychological factor on safely. The survey consisted of 34 questions about 4 factors like private external characteristic, psychological characteristic, characteristics on behavior, and experience and reason of disaster. As the result of the analysis of the multi regression model on the base of correlation of each of the major factors, psychological health, effort on practicing, and satisfaction on their life were the variables with high influence on the safety mind of workers. So, it is good safety strategy for effective working to maintain healthy life with optimistic minds, and try to practice actively as usual. After considering the result, for the development of safety education program for working, we have to consider psychological factors of our workers that influence their safety and try to improve the experimental education opportunity, and it will be effective.

• The Journal of Society for e-Business Studies
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• v.15 no.1
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• pp.119-137
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• 2010

The absence of a concrete method for economic analysis is one of the main reasons that the RFID is not so widespread. Through literature survey and a case study of a courier service company we propose a novel method of economic justification including cost and benefit analysis. In order to reflect the uncertainties caused by the RFID technology itself and the estimated investment cost, we propose optimistic, conservative and pessimistic estimations of benefits and a sensitivity analysis of investment costs. This paper may contribute the systematic evaluation of cost and benefit of RFID adoption.

• Journal of Global Scholars of Marketing Science
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• v.15 no.2
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• pp.141-159
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• 2005

In this research, we develope an estimation method for the estimation of the market potential in the new service (or product) diffusion model. The developed method is based on the ordered response model which can effectively incorporate the survey result of the multi-point scale intention for subscription as well as the responder's characteristics, the characteristics & attitudes of the related service. We also apply the developed method to an estimation of the market potential of the digital multimedia broadcasting (DMB) service. As a result, an optimistic and a pessimistic estimates of DMB market potential are 41.10% and 14.83% of the cellular subscribers respectively.

• Journal of the Korea Safety Management & Science
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• v.11 no.4
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• pp.15-24
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• 2009

The object of this study is to understand the psychological factor of the worker on safety and recommend the experimental factor of safety education program. The following are the methods of this study. We analyzed the statistical data from survey to workers(N=139) about the psychological factor on safety. The survey consisted of 34 questions about 4 factors like private external characteristic, psychological characteristic, characteristics on behavior, and experience and reason of disaster. As the result of the analysis of the multi regression model on the base of correlation of each of the major factors, psychological health, effort on practicing, and satisfaction on their life were the variables with high influence on the safety mind of workers. So, it is good safety strategy for effective working to maintain healthy life with optimistic minds, and try to practice actively as usual. After considering the result, for the development of safety education program for working, we have to consider psychological factors of our workers that influence their safety and try to improve the experimental education opportunity, and it will be effective.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.43 no.4
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• pp.229-235
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• 2020

Investors aim to maximize the return rate for their own investment, utilizing various information as possible as they can access. However those investors, especially individual investors, have limitations of interpretation of the domain-specific information or even the acquisition of the information itself. Thus, individual investors tend to make decision affectively and frequently, which may cause a loss in returns. This study aims to analyze analysts' target price and to suggest the strategy that could maximize individual's return rate. Most previous literature revealed that the optimistic bias exists in the analysts' target price and it is also confirmed in this study. In this context, this study suggests the upper limit of target rate of returns and the optimal value named 'alpha(α)' which performs the adjustment of proposed target rate to maximize excess earning returns eventually. To achieve this goal, this study developed an optimization problem using linear programming. Specifically, when the analysts' proposed target rate exceeds 30%, it could be adjusted to the extent of 59% of its own target rate. As apply this strategy, the investors could achieve 1.2% of excess earning rate on average. The result of this study has significance in that the individual investors could utilize analysts' target price practically.