• Wind and Structures
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• v.21 no.2
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• pp.223-239
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• 2015

Open decks are a widely used deck configuration in long-span cable-stayed bridges; however, incorporating aerodynamic countermeasures are advisable to achieve better aerodynamic performance than a bluff body deck alone. A sectional model of an open deck cable-stayed bridge with a main span of 400 m was selected to conduct a series of wind tunnel tests. The influences of five practical aerodynamic countermeasures on flutter and vortex-induced vibration (VIV) performance were investigated and are presented in this paper. The results show that an aerodynamic shape selection procedure can be used to evaluate the flutter stability of decks with respect to different terrain types and structural parameters. In addition, the VIV performance of $\prod$-shaped girders for driving comfortableness and safety requirements were evaluated. Among these aerodynamic countermeasures, apron boards and wind fairings can improve the aerodynamic performance to some extent, while horizontal guide plates with 5% of the total deck width show a significant influence on the flutter stability and VIV. A wind fairing with an angle of $55^{\circ}C$ showed the best overall control effect but led to more lock-in regions of VIV. The combination of vertical stabilisers and airflow-depressing boards was found to be superior to other countermeasures and effectively boosted aerodynamic performance; specifically, vertical stabilisers significantly contribute to improving flutter stability and suppressing vertical VIV, while airflow-depressing boards are helpful in reducing torsional VIV.

• Journal of Radiation Protection and Research
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• v.23 no.4
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• pp.243-249
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• 1998

The methodology for justification and optimization of the countermeasures related with contamination management of milk was designed based on the cost and benefit analysis. The application results were discussed for the deposition on August 15, when pasture is fully developed in Korean agricultural conditions. A dynamic food chain model DYNACON was used to estimate the time-dependent radioactivity of milk after the deposition. The considered countermeasures are (1) the ban of milk consumption (2) the substitution of clean fodder, which are effective in reducing the ingestion dose as well as simple and easy to carry out in the first year after the deposition. The total costs of the countermeasures were quantitatively estimated in terms of cost equivalent of doses and monetary costs. It is obvious that a fast reaction after the deposition is an important factor in cost effectiveness of the countermeasures. In most cases, the substitution of clean fodder was more effective countermeasure than the ban of consumption. A fast reaction after the deposition made longer justifiable/optimal duration of the countermeasure.

• International Journal of Highway Engineering
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• v.16 no.6
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• pp.149-158
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• 2014

PURPOSES : The bridge section of the expressway has a worse driving environment than the general section. However, traffic safety countermeasures are focused only on the bridge section. Traffic safety countermeasures on the section before entry to the bridge and the section after exit from the bridge are applied only when the bridge has a long-span section. Accordingly, this study will verify the necessity of extending the application of traffic safety countermeasures to areas that are affected by the bridge. METHODS : This study determines the areas that are affected by the bridge as well as the areas that are affected by locations with frequent traffic accidents and suggests the risk factors by affected areas through canonical discriminant analysis. For the analysis, traffic accident data for 3 years, which occurred on bridge sections in six major expressway lines, were used. RESULTS : The numbers of traffic accidents were 469 before the bridge, 281 on the bridge, and 468 after the bridge. The variables that have impact on the seriousness of accidents are as follows: speeding, excess manipulation of the steering wheel, and failure to secure safety distance for accidents that occurred before the bridge section; speeding, excess manipulation of the steering wheel, and dozing off for accidents that occurred on the bridge; and speeding and failure to secure safety distance for accidents that occurred after the bridge section. CONCLUSIONS : Areas affected by the bridge show higher accident rates than the bridge section; therefore, imposing traffic safety countermeasures on the integrated section of the bridge and the affected areas is required. It is believed that the results suggested in this study could be effectively used in the prevention of traffic accidents by imposing custom-made safety countermeasures for each section.

• Journal of Internet Computing and Services
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• v.13 no.4
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• pp.11-21
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• 2012

It is indispensable that aircrafts in electrical warfare settings endeavour to improve their survivability by selecting optimal countermeasures against threats. In this paper, we model the successful probabilities of aircraft survivability equipments that remove threats encountered, and also propose a framework for the aircrafts to autonomously decide their countermeasures. And then, we design the operational effectiveness of the aircraft survivability equipments, and quantitatively formulate the operational effectiveness into the form of reduction in lethality (RL). We actually show how the operational effectiveness can be computed in simulated example scenarios. To verify our framework proposed in this paper, we experimented with the successful probabilities of aircraft survivability equipments and the autonomous decision-making against threats in various electronic warfare settings. In the experiments, it turns out that our agents outperform the agents that randomly choose their countermeasures, which is 12% more efficient in their performance.

• Journal of Intelligence and Information Systems
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• v.26 no.3
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• pp.37-50
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• 2020

Information security has become an important issue in the world. Various information and communication technologies, such as the Internet of Things, big data, cloud, and artificial intelligence, are developing, and the need for information security is increasing. Although the necessity of information security is expanding according to the development of information and communication technology, interest in information security investment is insufficient. In general, measuring the effect of information security investment is difficult, so appropriate investment is not being practice, and organizations are decreasing their information security investment. In addition, since the types and specification of information security measures are diverse, it is difficult to compare and evaluate the information security countermeasures objectively, and there is a lack of decision-making methods about information security investment. To develop the organization, policies and decisions related to information security are essential, and measuring the effect of information security investment is necessary. Therefore, this study proposes a method of constructing an investment portfolio for information security measures using game theory and derives an optimal defence probability. Using the two-person game model, the information security manager and the attacker are assumed to be the game players, and the information security countermeasures and information security threats are assumed as the strategy of the players, respectively. A zero-sum game that the sum of the players' payoffs is zero is assumed, and we derive a solution of a mixed strategy game in which a strategy is selected according to probability distribution among strategies. In the real world, there are various types of information security threats exist, so multiple information security measures should be considered to maintain the appropriate information security level of information systems. We assume that the defence ratio of the information security countermeasures is known, and we derive the optimal solution of the mixed strategy game using linear programming. The contributions of this study are as follows. First, we conduct analysis using real performance data of information security measures. Information security managers of organizations can use the methodology suggested in this study to make practical decisions when establishing investment portfolio for information security countermeasures. Second, the investment weight of information security countermeasures is derived. Since we derive the weight of each information security measure, not just whether or not information security measures have been invested, it is easy to construct an information security investment portfolio in a situation where investment decisions need to be made in consideration of a number of information security countermeasures. Finally, it is possible to find the optimal defence probability after constructing an investment portfolio of information security countermeasures. The information security managers of organizations can measure the specific investment effect by drawing out information security countermeasures that fit the organization's information security investment budget. Also, numerical examples are presented and computational results are analyzed. Based on the performance of various information security countermeasures: Firewall, IPS, and Antivirus, data related to information security measures are collected to construct a portfolio of information security countermeasures. The defence ratio of the information security countermeasures is created using a uniform distribution, and a coverage of performance is derived based on the report of each information security countermeasure. According to numerical examples that considered Firewall, IPS, and Antivirus as information security countermeasures, the investment weights of Firewall, IPS, and Antivirus are optimized to 60.74%, 39.26%, and 0%, respectively. The result shows that the defence probability of the organization is maximized to 83.87%. When the methodology and examples of this study are used in practice, information security managers can consider various types of information security measures, and the appropriate investment level of each measure can be reflected in the organization's budget.

• Convergence Security Journal
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• v.13 no.5
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• pp.187-196
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• 2013

Recently, school violence has come to the fore as a social phenomenon. "Comprehensive countermeasures for eradication of school violence" as a policy safety are created by Safety Administration bureau and Ministry of Education, Science and Technology under the chairmanship of the Office of Prime Minister on Feb,2012. This policy is supposed to be test-operated for a year from March, 2012. but voices of concern about effectiveness have been brought up by some critics greatly. So 172 teachers in high school in Seoul were surveyed in order to examine the effectiveness of "Comprehensive countermeasures for eradication of school violence" with a questionnaire composed of 5 point Likert-type. Among the fundamental measures, there were a total of 12 countermeasures about 'Practices for personality education' (with the exception of unrelated one question). 'Expanding opportunities of various art education and Supporting reading activities' of them ranked highest on average. Then, 'Reflecting results of special feature related to character develops to the Selection of Admission officers and Self-directed learning was the next. And among the three countermeasures about 'Reinforcement of roles of the family and society', 'Pan governmental conducting annual campaign related to broadcast, press, civic group to combat school violence was highest. Finally, among the 7 countermeasures about 'Countermeasure about harmful factors of games and internet addiction', 'Reinforcement of preventive discipline about game and internet addiction' was highest and 'Development and Promotion of various educational contents for preventive discipline about game and internet addiction' was the next.

• Journal of Korean Society of Transportation
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• v.32 no.2
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• pp.93-105
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• 2014

This study evaluated the relative efficiency of mobile emission reduction countermeasures through a Data Envelopment Analysis (DEA) approach and determined the priority of countermeasures based on the efficiency. Ten countermeasures currently applied for reducing greenhouse gases and air pollution materials were selected to make a scenario for evaluation. The reduction volumes of four air pollution materials(CO, HC, NOX, PM) and three greenhouse gases($CO_2$, $CH_4$, $N_2O$) for the year 2027, which is the last target year, were calculated by utilizing both a travel demand forecasting model and variable composite emission factors with respect to future travel patterns. To estimate the relative effectiveness of reduction countermeasures, this study performed a super-efficiency analysis among the Data Envelopment Analysis models. It was found that expanding the participation in self car-free day program was the most superior reduction measurement with 1.879 efficiency points, followed by expansion of exclusive bus lanes and promotion of CNG hybrid bus diffusion. The results of this study do not represent the absolute data for prioritizing reduction countermeasures for mobile greenhouse gases and air pollution materials. However, in terms of presenting the direction for establishing reduction countermeasures, this study may contribute to policy selection for mobile emission reduction measures and the establishment of systematic mid- and long-term reduction measures.

• Research in Community and Public Health Nursing
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• v.29 no.1
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• pp.65-75
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• 2018

Purpose: This study aims to examine how elementary, middle and high school health teachers in Gyeonggi province react to infectious disease like MERS. Methods: This is a descriptive study using a convenience sample of 1,267 school health teachers. Results: When MERS was an epidemic, school health teachers who took the 'leading' role were 92.4%. A school heath teacher's countermeasures against infectious diseases showed a high score during MERS outbreak (3.81) compared to regular days (3.59). Conclusion: Based on such results, it has been determined that schools need to keep two types of procedures manual, such as 'countermeasures on a regular basis' and 'countermeasures in the event of a pandemic disease outbreak' manual in the staff offices so that anyone can view them at any time. It is necessary to prepare regulations to strengthen their authority so that school health teachers can take the role of control tower, in a professional capacity, when communicable disease is spreading. In order to prevent any confusion and chaos, there should be a unitary reporting system at each school when dealing with an epidemic. School health teachers need to get continuous training to reinforce their abilities to react to communicable diseases.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.5
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• pp.2084-2100
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• 2020

Operating system (OS) kernel function call graphs have been widely used in OS analysis and defense. However, most existing methods and tools for generating function call graphs are designed for application programs, and cannot be used for generating OS kernel function call graphs. This paper proposes a virtualization-based call graph generation method called Acquire in Trap (AIT). When target kernel functions are called, AIT dynamically initiates a system trap with the help of a virtualization technique. It then analyzes and records the calling relationships for trap handling by traversing the kernel stacks and the code space. Our experimental results show that the proposed method is feasible for both Linux and Windows OSs, including 32 and 64-bit versions, with high recall and precision rates. AIT is independent of the source code, compiler and OS kernel architecture, and is a universal method for generating OS kernel function call graphs.

• Fire Science and Engineering
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• v.20 no.2 s.62
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• pp.64-71
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• 2006

After destruction of the Naksansa which was due to Yangyang forest fire, this the fundamental research about the disaster prevention countermeasures of tradition buddhist temple cultural treasure was performed. The present condition of tradition buddhist temple and related laws were investigated and the present damage condition of the Naksansa was surveyed. Also, the fire damage cases of tradition buddhist temple and the fire laws and regulations were investigated, and the survey about disaster prevention countermeasures was carried out. This research drew up the basic material about the disaster prevention countermeasures of traditional buddhist temple.