• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권3호
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• pp.116-123
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• 2014

Purpose: The purpose of this study was to evaluate risks for wound dehiscence after guided bone regeneration (GBR) in dental implant surgery. Methods: Patients who received dental implant therapy with GBR procedure at Seoul National University Bundang Hospital (Seongnam, Korea) from June 2004 to May 2007 were included. The clinical outcome of interest was complications related to dental implant surgery. The factors influencing wound dehiscence, classified into patient-related factors, surgery-related factors and material-related factors, were evaluated. Results: One hundred and fifteen cases (202 implants) were included in this study. Wound dehiscence (19.1%) was considered a major complication. The risk of wound dehiscence was higher in males than in females (odds ratio=4.279, P =0.014). In the main graft, the allogenic group had the lowest risk of wound dehiscence (odds ratio=0.106, P =0.006). Though the external connection group had a higher risk of wound dehiscence than the internal connection group (odds ratio=2.381), the difference was not significant (P =0.100). Conclusion: In this study, male gender and main graft have the highest risk of wound dehiscence. To reduce wound dehiscence after GBR, instructions on postoperative care with supplementary procedure for the protection of the wound dehiscence is recommended, especially to male patients. A main graft with a gel base can reduce the risk of wound dehiscence.

• 경영과정보연구
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• 제4권
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• pp.309-325
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• 2000

Organizations rely on Secure ID resources today to handle vast amounts of information. Because the data can vary widely in type and in degree of sensitivity, employees need to be able to exercise flexibility in handling and protecting it. It would not be practical or cost-effective to require that all data be handled in the same manner or be subject to the same protection requirements. Without some degree of standardization, however inconsistencies can develop at introduce risks. Policy formulation is an important step toward standardization of security activities for ID resources. ID security policy is generally formulated from the input of many members of an organization, including security officials, line managers, and ID resource specialists. However, policy is ultimately approved and issued by the organization's senior management. In environments where employees feel inundated with policies, directives, guidelines and procedures, an ID security policy should be introduced in a manner that ensures that management's unqualified support is clear. The organization's policy is management's vehicle for emphasizing the commitment to ID security and making clear the expectations for employee involvement and accountability. This paper will discuss ID security Policy in terms of the different types (program-level and issue-specific), components, and Implementation of Expert System Simulation based on 4GL, PowerBuilder.

• 한국환경과학회지
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• 제16권3호
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• pp.247-253
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• 2007

Polycyclic aromatic hydrocarbons (PAHs) are a major concern because of their potential mutagenic and carcinogenic risks to human beings. One of these harmful, yet commonly observed PAHs is pyrene. Pyrene is one of the 16 PAHs listed by the United States Environmental Protection Agency as priority pollutants. The purposes of this research are to develop a method of pretreatment for PAH contaminants prior to a typical biological treatment and to demonstrate the biodegradablity of these compounds. Since pyrene is non-polar, hexane was chosen as a solvent to effectively dissolve pyrene. Pyrene solutions were treated with ozone, as it has hish oxidation capacity and electrophilic character. The intermediates and byproducts of pyrene were dissolved in alkaline water at pH 11.4 and neutralized to test for $BOD_5$, COD, and toxicity. These solutions were further ozonated and assessed of biodegradability. The first-order rate constant to was found to be between $0.121day^{-1}$ and $0.081 day^{-1}$, depending on the duration of reozonation. The $BOD_5/COD$ ratio was found to 0.66. The toxicity test showed that after 10 min of reozonation time, the byproducts and intermediates of pyrene were within the lion-toxic range of ${\pm}10%$ inhibition for E-Coli bacteria.

• 한국항해항만학회지
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• 제41권5호
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• pp.287-296
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• 2017

The Formal Safety Assessment (FSA) is a structured and systematic methodology developed by the IMO, aimed at assessing the risk of vessels and recommending the method to control intolerable risks, thereby enhancing maritime safety, including protection of life, health, the marine environment and property, by using risk analysis and cost-benefit assessment. While the FSA has mostly been applied to merchant vessels, it has rarely been applied to a DP vessel, which is one of the special purpose vessels in the offshore industry. Furthermore, most of the FSA has been conducted so far by using the Fault Tree Analysis tool, even though there are many other risk analysis tools. This study carried out the FSA for safe operation of DP vessels by using the Bayesian network, under which conditional probability was examined. This study determined the frequency and severity of DP LOP incidents reported to the IMCA from 2001 to 2010, and obtained the Risk Index by applying the Bayesian network. Then, the Risk Control Options (RCOs) were identified through an expert brainstorming and DP vessel simulations. This study recommends duplication of PRS, regardless of the DP class and PRS type and DP system specific training. Finally, this study verified that the Bayesian network and DP simulator can also serve as an effective tool for FSA implementation.

• Nuclear Engineering and Technology
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• 제49권3호
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• pp.517-524
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• 2017

Cyber security is an important issue in the field of nuclear engineering because nuclear facilities use digital equipment and digital systems that can lead to serious hazards in the event of an accident. Regulatory agencies worldwide have announced guidelines for cyber security related to nuclear issues, including U.S. NRC Regulatory Guide 5.71. It is important to evaluate cyber security risk in accordance with these regulatory guides. In this study, we propose a cyber security risk evaluation model for nuclear instrumentation and control systems using a Bayesian network and event trees. As it is difficult to perform penetration tests on the systems, the evaluation model can inform research on cyber threats to cyber security systems for nuclear facilities through the use of prior and posterior information and backpropagation calculations. Furthermore, we suggest a methodology for the application of analytical results from the Bayesian network model to an event tree model, which is a probabilistic safety assessment method. The proposed method will provide insight into safety and cyber security risks.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권7호
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• pp.3671-3689
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• 2019

Software defined networking brings unique security risks such as control plane saturation attack while enhancing the performance of wireless sensor networks. The attack is a new type of distributed denial of service (DDoS) attack, which is easy to launch. However, it is difficult to detect and hard to defend. In response to this, the attack threat model is discussed firstly, and then a DDoS attack prevention extension, called FuzzyGuard, is proposed. In FuzzyGuard, a control network with both the protection of data flow and the convergence of attack flow is constructed in the data plane by using the idea of independent routing control flow. Then, the attack detection is implemented by fuzzy inference method to output the current security state of the network. Different probabilistic suppression modes are adopted subsequently to deal with the attack flow to cost-effectively reduce the impact of the attack on the network. The prototype is implemented on SDN-WISE and the simulation experiment is carried out. The evaluation results show that FuzzyGuard could effectively protect the normal forwarding of data flow in the attacked state and has a good defensive effect on the control plane saturation attack with lower resource requirements.

• The Journal of Asian Finance, Economics and Business
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• 제8권7호
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• pp.111-120
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• 2021

Takaful, which is an Islamic insurance instrument, manages risks in business, according to Shariah (Islamic law) principles and offers risk protection and savings assets. The study analyzes the comparative efficiency of takaful insurance companies by implementing empirical research. The study also provides a comprehensive literature review on the efficiency analysis of the takaful industry. The empirical part presents a wide range of efficiency comparisons of 41 takaful insurance companies in 16 countries between 2009 and 2014. The data enveloping analysis technique is utilized using the rDEA package in the R environment to compute the efficiency score. In the study, the technical efficiency, overall technical efficiency, and pure technical efficiency are calculated and compared per year and per country. The findings of the study suggest that the overall average efficiency scores of takaful companies are considerably high. The study results also indicate that the excess in the consumption of inputs decreases while the deficit in achieved outputs has been declining in the covered period. The study suggests the managers of the takaful companies can use the target efficiency scores, which are calculated by using the DEA analysis, as an ideal reference benchmark for planning their inputs and outputs.

• Safety and Health at Work
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• 제12권2호
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• pp.261-267
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• 2021

Background: The series of serious industrial accidents in recent years at contractors to large companies has highlighted risk outsourcing as a real and urgent problem. This study aims to review the difference in the degree of risk exposure and the occurrence of industrial accidents depending on the type of company relations. Among in-house contractors, the focus will be on those handling hazardous chemicals that include companies for which outsourcing requires approval. Methods: This study uses the 9th wave of the Industrial Safety and Health Survey (2018). For determining the degree of risk exposure, the occurrence of industrial accidents, and industrial accident rate, multivariate, logistic, and fractional logit, regression analyses were used, respectively. Results: First, In-house contractors' degree of risk exposure is higher than that of the client companies. In particular, this gap is even greater for companies dealing with chemicals. Second, among only those that handle hazardous chemicals, in-house contractors do show a significantly higher rate of industrial accident occurrence. Third, In-house contractors have a significantly higher rate of industrial accidents from diseases than client companies. Conclusion: The analysis supports the intent of the legal amendment that strengthens the protection of in-house contracted workers who handle hazardous chemicals. Second, the results of this study suggest that safety and health management must go beyond legal compliance and ensure that it has substance and effectiveness. Last, there should be policy consideration is necessary to reduce attempts to hide industrial accidents.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.466-473
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• 2021

Fire protection is one of important issues to ensure safety and reduce risks of nuclear power plants (NPPs). While robust programs to shut down commercial reactors in any fires have been successfully maintained, the concept and associated regulatory requirements are constantly changing or strengthening by lessons learned from operating experiences and information all over the world. As part of this context, it is necessary not only to establish specific fire hazard assessment methods reflecting the characteristics of research reactors and educational reactors but also to make decisions based on advancement encompassing numerical analyses and experiments. The objectives of this study are to address fire simulation in the control room of an educational reactor and to discuss integrity of digital console in charge of main operation as well as analysis results through comparison. Three electrical fire scenarios were postulated and twenty-four thermal analyses were carried out taking into account two turbulence models, two cable materials and two ventilation conditions. Twelve supplementary thermal analyses and six subsequent structural analyses were also conducted for further examination on the temperature and heat flux of cable and von Mises stress of digital console, respectively. As consequences, effects of each parameter were quantified in detail and future applicability was briefly discussed. On the whole, higher profiles were obtained when Deardorff turbulence model was employed or polyvinyl chloride material and larger ventilation condition were considered. All the maximum values considered in this study met the allowable criteria so that safety action seems available by sustained integrity of the cable linked to digital console within operators' reaction time of 300 s.

• Nuclear Engineering and Technology
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• 제53권2호
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• pp.549-561
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• 2021

Indonesia has policies and strategies for the management of radioactive waste and spent nuclear fuel that arises from the use of nuclear research and development facilities, including three research reactors, and the use of radioisotopes in medicine and industries. The Indonesian government has provided extensive facilities such as an independent regulatory organization (BAPETEN) and a centralized radioactive waste management organization (CRWT-BATAN). Further, the presence of regulations and several international conventions guarantee the protection of the public from all risks due to handling radioactive waste and spent nuclear fuel. However, the sustainability of radioactive waste management in the future faces various challenges, such as disposal issues related to not only to site selection but also financing of radioactive waste management. Likewise, the problem of transportation persists; as an archipelago country, Indonesia still struggles to manage the infrastructure required for the transport of radioactive materials. The waste from the production of the radioisotopes, especially from the production of 99Mo, requires special attention because BATAN has never handled it. Indonesia should also resolve the management of NORM from various activities. In Indonesia, the definition of radioactive waste does not include NORM. Therefore, the management of this waste needs revision and improvement on the regulations, infrastructure, and technology.