• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.19 no.3
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• pp.297-306
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• 2021

In this study, basic strategies for the decommissioning and site remediation of the Fukushima Daiichi Nuclear Power Station (FDNPS) were investigated. Six scenarios were formulated based on two of the three decommissioning strategies of nuclear power plants defined by the International Atomic Energy Agency (IAEA): immediate dismantling and deferred dismantling. A multicriteria decision analysis was performed to analyze the preferences of the options from the viewpoints of the timeframe to complete decommissioning, the resulting waste, the site usability, and the availability of the radioactive waste disposal route. The same six scenarios were applied to both the FDNPS and the nuclear power plants that ceased operation after a normal plant life cycle for comparison. For the FDNPS, the decommissioning project involved fuel debris retrieval, dismantling, and site remediation. The analysis results suggest that the balance between the amount of waste and the time to achieve the end state may be one of the most critical factors to consider when planning the decommissioning and site remediation of the FDNPS.

• Women's Health Nursing
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• v.8 no.3
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• pp.325-334
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• 2002

To identify strategies to prevent sexual problems in teenage girls, respondents in this study answered two open-ended questions: "What are strategies for teenage school girls to prevent unwanted coitus?" and "What are strategies for teenage girls to prevent pregnancy?" The respondents were 12,733 girls from an accessible population of 19,000, a multi-stage cluster sample from a population of 1,988,902 girls attending 4,684 schools in the seven largest cities and nine provinces in Korea. Data were collected by mail between October 2 and October 28, 2000. The response rate was 68.9%. The total number of responses for the first question was 10,345, and for the second, 9,624. Data were analyzed by content analysis. The results of this study are: 1. According to priority, frequent strategies to prevent unwanted coitus were, self assertiveness (35.7%), heterosexual interaction training (24.6%), sex education (21.2%), and innovations in the system of social culture (4.7%). The order of priority was the same whether the respondents had experienced coitus or not. 2. According to priority, frequent strategies to prevent pregnancy were, heterosexual interaction training (27.4%), sex education (26.2%), contraceptive use and induced abortion (21.4%), and innovations in the system of social culture (3.2%). The first priority for the respondents who had not experienced coitus was heterosexual interaction training (27.7%) but contraceptive use (35.5%) was the first priority for the group who had experienced coitus. In sex education, a focus on contraceptive use for teenage girls who have experienced coitus and on heterosexual interaction training for those who have not, would strengthen preventive strategies for these two sexual problems. Assertiveness training as part of sex education would further strengthen prevention strategies.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.6
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• pp.117-126
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• 1994

This paper deals with a robust semi-active control algorithm which is applicable to a semi-active suspension with a multi-state damper. Since the controllable damping rates are discrete in case of a multi-state semi-active damper, the desired damping rate can not be produced exactly even if force-velocity relations of a multi-state semi-active damper is completely known. In addition, damping characteristics of the semi-active dampers are different from damper to damper. A robust nonlinear control law based on sliding control is developed. The main objective of the proposed control strategies is to improve ride quality by tracking the desired active force with a multi-state damper of which the force-velocity relations are "not" completely known. The performance of th proposed semi-active control law is numerically compared to those of the control law based on a bilinear model and a passive suspension. The proposed control algorithm is robust to nonlinear characteristics and uncertainty of the force-Velocity relations of multi-state dampers.

• International Journal of Computer Science & Network Security
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• v.23 no.8
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• pp.159-167
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• 2023

Objective: • To detect black hole and warm hole attacks in wireless sensor networks. • To give a solution for energy depletion and security breach in wireless sensor networks. • To address the security problem using strategic decision support system. Methods: The proposed stackelberg game is used to make the spirited relations between multi leaders and multi followers. In this game, all cluster heads are acts as leaders, whereas agent nodes are acts as followers. The game is initially modeled as Quadratic Programming and also use backtracking search optimization algorithm for getting threshold value to determine the optimal strategies of both defender and attacker. Findings: To find optimal payoffs of multi leaders and multi followers are based on their utility functions. The attacks are easily detected based on some defined rules and optimum results of the game. Finally, the simulations are executed in matlab and the impacts of detection of black hole and warm hole attacks are also presented in this paper. Novelty: The novelty of this study is to considering the stackelberg game with backtracking search optimization algorithm (BSOA). BSOA is based on iterative process which tries to minimize the objective function. Thus we obtain the better optimization results than the earlier approaches.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.793-794
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• 2013

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 2006.07a
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• pp.241-241
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• 2006

• Journal of Elementary Mathematics Education in Korea
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• v.20 no.4
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• pp.717-735
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• 2016

For teaching division-with-remainder(DWR) problems, it is necessary to know students' strategies and errors about DWR problems. The purpose of this study is to investigate and analyze students' strategies and errors of DWR problems and to make some meaningful suggestions for teaching various methods of solving DWR problems. We constructed a test which consists of fifteen DWR problems to investigate students' solving strategies and errors. These problems include mathematical as well as syntactic structures. To apply this test, we selected 177 students from eight elementary schools in various districts of Seoul. The results were analyzed both qualitatively and quantitatively. The sixth graders' strategies can be classified as follows : Single strategies, Multi strategies and Assistant strategies. They used Division(D) strategy, Multiplication(M) strategy, and Additive Approach(A) strategy as sub-strategies. We noticed that frequently used strategies do not coincide with strategies for their success. While students in middle group used Assistant strategies frequently, students in higher group used Single strategies frequently. The sixth graders' errors can be classified as follows : Formula error(F error), Calculation error(C error), Calculation Product error(P error) and Interpretation error(I error). In this study, there were 4 elements for syntaxes in problems : large number, location of divisor and dividend, divisor size, vocabularies. When students in lower group were solving the problems, F errors appeared most frequently. However, in case of higher group, I errors appeared most frequently. Based on these results, we made some didactical suggestions.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.410-425
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• 1997

Buildings are mostly under part load conditions causing an inefficient system operation in terms of energy consumption. It is critical to operate building air-conditioning system with a scientific or optimal manner which minimizes energy consumption and maintains thermal comfort by matching building sensible and latent loads. Little research has been performed in developing general methodologies for the optimal operation of air-conditioning system. Based on this research motivation, system simulation program was developed by adopting various equipment operating strategies which are energy efficient especially for humidity control in summer. A numerical optimization technique was utilized to search optimal solution for multi-independent variables and then linked to the developed system simulation model within a mam program. The main goal of the study is to provide a systematic framework and guideline for the optimal operation of air-conditioning system focusing on air-side. For given cooling loads and ambient outdoor conditions the optimal operating strategies of a commercial building are determined by minimizing a constrained objective function by a nonlinear programming technique. Desired space setpoint conditions were found through evaluating the trade-offs between comfort and system power consumption. The results show that supply airflow rate and compressor fraction play main roles in the optimization process. It was found that variable setpoint optimization technique could produce lower indoor humidity level demanding less power consumption which will be benefits for building applications of humidity problem.

• Korean Journal of Health Education and Promotion
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• v.27 no.4
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• pp.177-188
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• 2010

Objectives: The aim of this study was to examine factors related to smoking behavior, and to develop multilevel communication strategies for smoking cessation. Methods: This paper reviewed theories and empirical findings with currents ecological models to develop communication strategies. Theory comparison was also performed to identify important mediators in the process of smoking cessation. Results: Factors that have been identified to influence smoking behavior ranges from individual perception, attitudes and self efficacy toward smoking to organizational norms, regulations, community capacity, media advocacy and public smoking regulation policy. In order to address these multi-level determinants of smoking behavior, objectives and strategies for smoking cessation intervention were developed utilizing ecological perspectives to cover intrapersonal, interpersonal(mainly family member and peers), organizational and community/public policy level factors. Conclusion: Multilevel approaches have advanced the existing knowledge on determinants of health behaviors. New direction of research focusing on testing multilevel intervention approaches should be expanded to inform the efficacy of applying social ecological models to health behavior change process.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.5
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• pp.1920-1937
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• 2015

Network environment has been under constant threat from both malicious attackers and inherent vulnerabilities of network infrastructure. Existence of such threats calls for exhaustive vulnerability analyzing to guarantee a secure system. However, due to the diversity of security hazards, analysts have to select from massive alternative hardening strategies, which is laborious and time-consuming. In this paper, we develop an approach to seek for possible hardening strategies and prioritize them to help security analysts to handle the optimal ones. In particular, we apply a Risk Flow Attack Graph (RFAG) to represent network situation and attack scenarios, and analyze them to measure network risk. We also employ a multi-objective genetic algorithm to infer the priority of hardening strategies automatically. Finally, we present some numerical results to show the performance of prioritizing strategies by network risk and hardening cost and illustrate the application of optimal hardening strategy set in typical cases. Our novel approach provides a promising new direction for network and vulnerability analysis to take proper precautions to reduce network risk.