• Environmental and Resource Economics Review
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• v.26 no.3
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• pp.359-398
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• 2017

Uncertainty is central to energy and climate policy. A growing number of literature show that almost all components of energy and climate models are, to some extent, uncertain and that the effect of uncertainty on the model outputs, in turn policy recommendations, is significantly large. Most existing energy and climate-economy models developed and used in Korea, however, do not take uncertainty into account explicitly. Rather, many models conduct a deterministic analysis or do a simple (limited) sensitivity analysis. In order to help social planners to make more robust decisions (across various plausible situations) on energy and climate change issues, an uncertainty analysis should be conducted. As a first step, this paper reviews the theory of decision making under uncertainty and the method for addressing uncertainty of existing probabilistic energy and climate-economy models. In addition, the paper proposes a strategy to apply an uncertainty analysis to energy and climate-economy models used in Korea. Applying the uncertainty analysis techniques, this paper revises the FUND model and investigates the impacts of climate change in Korea.

• Korean journal of applied entomology
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• v.41 no.1
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• pp.67-73
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• 2002

Studies were conducted to investigate the control effects of several insecticides on Apolygus(=Lygocoris) spinolae(Meyer-Dur) and to develop its management strategies in grapevine yards. Of insecticides which were applied by farmers in commercial grapevine yards, chlorpyrifos, parathion, fenvalerate, and esfenvalerate$.$fenitrothion showed good control effects against A. spinolae. In designed field experiments of fenitrothion and chlorpyrifos for the evaluation of A. spinolae control, both insecticides showed high control efficacy of 94.8 and 91.6%, respectively. The damage of A. spinolae was examined in a grapevine yard, where five different combinations of application timing and number were treated with fenitrothion to assess yield losses (average cluster weight) by A. spinolae. There were no significant differences among average cluster weights of sprayed vines; 466.0 g in sprayed vines on 2 to 3 leaves unfolded stage, 460.7g in sprayed vines on flower separating stage, 465.0 g in sprayed vines each on 2 to 3 leaves unfolded and flowers separating stage, and 487.4 g in sprayed vines each on 2 to 3 leaves unfolded, flowers separating and fruit set stage. Weights of fruit clusters of unsprayed vines was significantly lower than those of sprayed vines. Based on yield and spray cost, chemical control on 2 to 3 leaves unfolded stage produced higher net income than each spray on 2 to 3 leaves unfolded and flower separating stage (i.e., two times of spray), and produced similar net income as each spray on 2 to 3 leaves unfolded, flowers separating and fruit set stage (i.e., three times of spray). Thus, the 2 to 3 leaves unfolded stage was economical spray timing to controlA. spinolae in grapevine yards. Also, management strategies for A. spinolae were discussed.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.392-399
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• 2003

This paper discusses the validities of insulating curing of cold weather concreting at early stage by applying insulation forms. Tests were carried out using modified insulating form combining existing insulating form and various other insulations in order to develop improved insulation form. Temperature history of concrete using various insulating forms and insulation was measured to determine most effective combination of insulting form. According to results, as for the wall form, under the curing temperature of $-10^{\circ}C$, the temperature of concrete using Euro form drops sharply before 24 hours and lasts below $0^{\circ}C$ for 7 hours. The temperature of concrete using the form combining Polypropylene panel, styrofoam and plywood panel keep above $0^{\circ}C$. And, it is confirmed that the form mentioned above has a favorable effects on enhancing strength development of concrete and the cost to make the forms shows more reasonable than that of existing forms. However, as for the combination methods of insulation form for slab, which is composed of insulating form at the bottom of slab and various surface curing materials at the top of slab, in case of exposed condition at the top of slab, temperature history of concrete goes below $0^{\circ}C$ after 10 hours. In case of the combination of vinyl sheet and curing blanket, it drops below $0^{\circ}C$ after 42 hours. However, in case of the combination of vinyl, styrofoam and curing blanket, it does not go below $0^{\circ}C$ until 55 hours. Accordingly, compared to the case of exposure and the combination of vinyl and curing blanket, it indicates that the combination mentioned above has more effective insulating performance.

• Journal of the Korea Concrete Institute
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• v.22 no.1
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• pp.19-27
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• 2010

Aging and severe environments are major causes of damage in reinforced concrete (RC) structures such as buildings and bridges. Deterioration such as concrete cracks, corrosion of steel, and deformation of structural members can significantly degrade the structural performance and safety. Therefore, effective and easy-to-use methods are desired for repairing and strengthening such concrete structures. Various methods for strengthening and rehabilitation of RC structures have been developed in the past several decades. Recently, FRP composite materials have emerged as a cost-effective alternative to the conventional materials for repairing, strengthening, and retrofitting deteriorating/deficient concrete structures, by externally bonding FRP laminates to concrete structural members. The main purpose of this study is to investigate the effectiveness of adaptive neuro-fuzzy inference system (ANFIS) in predicting behavior of circular type concrete column retrofitted with FRP. To construct training and testing dataset, experiment results for the specimens which have different retrofit profile are used. Retrofit ratio, strength of existing concrete, thickness, number of layer, stiffness, ultimate strength of fiber and size of specimens are selected as input parameters to predict strength, strain, and stiffness of post-yielding modulus. These proposed ANFIS models show reliable increased accuracy in predicting constitutive properties of concrete retrofitted by FRP, compared to the constitutive models suggested by other researchers.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.2
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• pp.71-78
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• 2014

There is a big risk of bullet impact because military rotorcraft is run in the battle environment. Due to the bullet impact, the rapid increase of the internal pressure can cause the internal explosion or fire of fuel cell. It can be a deadly damage on the survivability of crews. Then, fuel cell of military rotorcraft should be designed taking into account the extreme situation. As the design factor of fuel cell, the internal fluid pressure, structural stress and bullet kinetic energy can be considered. The verification test by real object is the best way to obtain these design data. But, it is a big burden due to huge cost and long-term preparation efforts and the failure of verification test can result in serious delay of a entire development plan. Thus, at the early design stage, the various numerical simulations test is needed to reduce the risk of trial-and-error together with prediction of the design data. In the present study, the bullet impact numerical simulation based on SPH(smoothed particle hydrodynamic) is conducted with the commercial package, LS-DYNA. Then, the resulting equivalent stress, internal pressure and bullet's kinetic energy are evaluated in detail to examine the possibility to obtain the configuration design data of the fuel cell.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.499-504
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• 2005

Polymer concrete shows excellent mechanical properties and chemical resistance compared with conventional normal cement concrete. The polymer concrete Is drawing a strong interest as high-performance materials in the construction industry Resins using recycled PET offer the possibility of a lower source cost of materials for making useful polymer concrete products. Also the recycling of PET in polymer concrete would help solve some of the solid waste problems Posed by plastics and save energy. An objective of this paper is to estimate the damage of sulfuric acid, through investigating recycled PET polymer concrete, immersed at sulfuric acid solution for 84 days. As a result of testing, recycled PET PC, used $CaCO_3$ as filler, makes a problem of appearance and strength if they are exposed for long term at corrosion environment. On the other hand, recycled PET PC, used fly-ash as filler, had less effect on decrease in weight and strength. Recycled PET PC is excellent chemical resistance, resulting in the role of unsaturated polyester resin which consists of polymer chain structure accomplishes bond of aggregates and filler strongly. Also, recycled PET PC, used fly-ash as filler, is stronger resistance of sulfuric acid corrosion than $CaCO_3$, because it is composed of $SiO_2$ and very strong glassy crystal structure. Therefore, recycled PET PC, used fly-ash as filler, is available under corrosion circumstances like sewer pipe or waste disposal plant.

• Journal of the Korea Convergence Society
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• v.8 no.9
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• pp.1-7
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• 2017

As the network environment develops and speeds up, a lot of smart devices is developed, and a high-speed smart society can be realized while allowing people to interact with objects. As the number of things Internet has surged, a wide range of new security risks and problems have emerged for devices, platforms and operating systems, communications, and connected systems. Due to the physical characteristics of IoT devices, they are smaller in size than conventional systems, and operate with low power, low cost, and relatively low specifications. Therefore, it is difficult to apply the existing security solution used in the existing system. In addition, IoT devices are connected to the network at all times, it is important to ensure that personal privacy exposure, such as eavesdropping, data tampering, privacy breach, information leakage, unauthorized access, Significant security issues can arise, including confidentiality and threats to facilities. In this paper, we investigate cases of security threats and cases of network of IoT, analyze vulnerabilities, and suggest ways to minimize property damage by Internet of things.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.1
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• pp.137-147
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• 2011

This study investigated the perception and attitude to leftover food at school food service by the questionnaire survey of the elementary school students in Gwangju area. The school food service satisfaction was neutral and school food service cost and quality was satisfactory. The dissatisfaction of school food service was shown as unkind staffs and a shortage for fruit and beverage. The kinds of leftover food were seasoned vegetables and kimchi. The reasons for leftover food were unfavorite food and the frequency was shown as once or twice a week. For the order of eating food, the subject first ate food they had tried. The highest kind of an unbalanced diet was beans and minor grains. To reduce food waste, many students perceived that tasty food, education by a class teacher in class that it could pollute environment and do us damage, recycling as livestock feed, 'No Plate Waste Day' organized by school would be a feasible method to reduce food waste. The nutrient intake of eaten food was significantly higher for all nutrients in the group receiving food waste education than the control group (p<0.001).

• Journal of Korean Society of Disaster and Security
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• v.11 no.1
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• pp.31-38
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• 2018

The 99.1% of small dam and most of the levees in Korea are soil dam which can be constructed with lower cost and less effort compared with ones made of concrete. However, they are so vulnerable to overflow. Sudden collapses of these strucrues lead to increase flow rate rapidly, which may cause catastrophic problems in downstream regions. In this study, the experimental study on the collapse delay effect of riprap that was laid on slope of soil levee was carried out. A prismatic rectangular open channel was used and three different sizes of the riprap were installed on slope of a scaled earth dam. A new formula for the collapse time of the levee with the installation of riprap was presented, using the previous researches and the dimensional analysis. In this process, an unsteady flow condition was considered to derive the deviation time of the riprap. And additional experiments were conducted to understand the effect of reinforcement of riprap, and it was found that the reinforcement of riprap was more effective than twice sizing of intial riprap. If the collapse time is delayed, EAP (Emergency Action Plan) and forecasting can greatly reduce the degree of flood damage. Also, it will be meaningful that the results of this study are used for river design.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.471-480
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• 2016

Recently, the damage of cyber attack toward infra-system, national defence and security system is gradually increasing. In this situation, military recognizes the importance of cyber warfare, and they establish a cyber system in preparation, regardless of the existence of threaten. Thus, the study of Intrusion Detection System(IDS) that plays an important role in network defence system is required. IDS is divided into misuse and anomaly detection methods. Recent studies attempt to combine those two methods to maximize advantagesand to minimize disadvantages both of misuse and anomaly. The combination is called Hybrid IDS. Previous studies would not be inappropriate for near real-time network environments because they have computational complexity problems. It leads to the need of the study considering the structure of IDS that have high detection rate and low computational cost. In this paper, we proposed a Hybrid IDS which combines C4.5 decision tree(misuse detection method) and Weighted K-means algorithm (anomaly detection method) hierarchically. It can detect malicious network packets effectively with low complexity by applying mutual information and genetic algorithm based efficient feature selection technique. Also we construct upgraded the the hierarchical structure of IDS reusing feature weights in anomaly detection section. It is validated that proposed Hybrid IDS ensures high detection accuracy (98.68%) and performance at experiment section.