• Structural Engineering and Mechanics
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• v.75 no.1
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• pp.19-32
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• 2020

Due to repetitive traffic loadings and environmental attacks, reinforced concrete (RC) bridge deck slabs are suffering from severe degradation, which makes structural repairing an urgency. In this study, the fatigue performance of an RC bridge deck repairing technique using ultra-high performance fiber reinforcement concrete (UHPFRC) overlay is assessed experimentally with a wheel-type loading set-up as well as analytically based on finite element method (FEM) using a crack bridging degradation concept. In both approaches, an original RC slab is firstly preloaded to achieve a partly damaged RC slab which is then repaired with UHPFRC overlay and reloaded. The results indicate that the developed analytical method can predict the experimental fatigue behaviors including displacement evolutions and crack patterns reasonably well. In addition, as the shear stress in the concrete/UHPFRC interface stays relatively low over the calculations, this interface can be simply simulated as perfect. Moreover, superior to the experiments, the numerical method provides fatigue behaviors of not only the repaired but also the unrepaired RC slabs. Due to the high strengths and cracking resistance of UHPFRC, the repaired slab exhibited a decelerated deterioration rate and an extended fatigue life compared with the unrepaired slab. Therefore, the proposed repairing scheme can afford significant strengthen effects and act as a reference for future practices and engineering applications.

• Journal of Korean Medical classics
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• v.22 no.3
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• pp.145-160
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• 2009

The most famous thought of Dongjungseo's must be 'the Sky-Earth Response Theory.' The theory includes the Same 'Gi' Correspondence(the Same Category Homology) and explains the relationship between the nature and the men based on Yin-Yang. This theory, commonly studied by the scholars of the political science, however, has been constituting the foundation of the oriental medicine. Also, he insists many other theories related to Yin-Yang including the natural calamity, the treatise of human nature, the name and reality, and the national school of Confucianism, etc. This paper covers the Yin-Yang theory, particularly with regard to ethics. politics, human nature of Dongjungseo, and the comparison of his Yin-Yang and that of the Emperor Inner Cannon. Dongjungseo insists on the harmony of Yin-Yang just only in the area of health care, excluding other areas such as state and family governance. However, in contrast, he asserts the Yang central idea for what he defined as the order of a family, a society and a state. This presents his contradiction and logicality. In the last part of this paper, his logical flaws would be discussed and analysed. However, he is a lucky scholar, because his Yang central idea has been successfully governing peoples for a long time, despite such imperfection and contradiction in his studies.

• Journal of Korea Multimedia Society
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• v.23 no.2
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• pp.293-300
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• 2020

Since the communication networks like the Internet collapses at disaster and calamity sites, a maintenance system that can be operated offline is required for the maintenance of various facilities. In this paper, we propose a system that memory tags attached on the facilities may transmit the emergency manual to a smart-phone, and the smart phone displays it off-line. The main issue is to design low energy mode memory tags. This study presents two kinds of methods and analyzes each's energy consumption mode. The first one is to develop memory tags by using one chip, and the next one is to design memory tags by forming multi-modules. Both ways show proper application fields under the low energy mode. This research selects the off-line maintenance system by using one chip design, and proposes the direction of contents for enhancing the effectiveness of the system. And we expect that this memory tags will be valuable for disaster scenes as well as battle fields.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.228-230
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• 2002

Recently, electric power reliability of our country has been improved. However, there are still remaining problems which are short-duration variations like instantaneous and momentary interruption and voltage sag by nature calamity ; typhoon, lightning, snow, etc. Besides, power quality ; harmonics, caused by using power electronics equipments, become a hot issue Malfunction of controller and stop machinery, and losing the important data are caused by poor power quality at a couple of second. Due to those, UPS, which is made up battery, has being used, but there are several disadvantages ; long charge and discharge time, environmental problem by acid and heavy metal, and short life time. As generally know, micro-SMES is a method to settle those mentioned. However, there need huge system apparatuses in order to verify the effect of system efficiency and stability considering the size of micro-SMES, the sort of converter type, and various conditions ; inner temperature, magnetic field, quench characteristic of micro-SMES, and etc. In this paper, in order to bring the mentioned above to a settlement, a micro-SMES is modeled with characteristics of micro-SMES is interfaced to EMTOC program using Fortran program interface method. We obtained hopeful answers and made the simulation model of micro SMES.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.11
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• pp.5556-5573
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• 2017

As a main component of Internet of Things (IoTs), the wireless sensor networks (WSNs) have been widely applied to various areas, including environment monitoring, health monitoring of human body, farming, commercial manufacture, reconnaissance mission in military, and calamity alert etc. Meanwhile, the privacy concerns also arise when the users are required to get the real-time data from the sensor nodes directly. To solve this problem, several user authentication and key agreement schemes with a smart card and a password have been proposed in the past years. However, these schemes are vulnerable to some attacks such as offline password guessing attack, user impersonation attack by using attacker's own smart card, sensor node impersonation attack and gateway node bypassing attack. In this paper, we propose an improved scheme which can resist a wide variety of attacks in WSNs. Cryptanalysis and performance analysis show that our scheme can solve the weaknesses of previously proposed schemes and enhance security requirements while maintaining low computational cost.

• Journal of the Korean Society of Marine Environment & Safety
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• v.1 no.2
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• pp.107-118
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• 1995

This study is for decision making on distribution of resources so as to improve the effectiveness of initial disaster relief efforts. It is very important that relief efforts should be accomplished appropriately at the initial disaster. Furthermore, efficient allocation of relief resources such as rescuer, shelter, relief goods, relief funds, medical and relief equipments is also the first step to achieve main objective of relief efforts when disaster occurs. For this purpose, this study establishes flood as a imaginery disaster and develops a model for efficient distribution of resources when flood outbreaks. This model fixes initial 72 hours, which is subdivided into three intervals, as a initial disaster range. The model is to set a prioity against alloction of relief resources by each time zone which is related to damaged degree( Red Tag, Yellow Tag, Green Tag). Experts in this field input their experience into this model, and these are analyzed by Analytic Hierachy Process(AHP)/Expert Choice(EC) software. Therefore, we can decide a prioity against distribution of resources by each time zone which is in accordance with damaged degree. The result of this study would be helpful to a person who is in charge of relief from calamity in order him to make a decision toward distribution of resources.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.213-217
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• 2009

Weather factors affect cost increases and progress management under construction. Because progress schedule is delayed by weather factors, the construction costs are increased. It is an essential element to control the progress schedule applying weather factors to the progress management. This study applies monthly working-day percentages which is estimated by databases of past weather information to RTPM system. Through do progress management in construction projects exactly, will try to minimize risk of process control that do that is to weather factors. Also, will compare calamity in safety supervision side that do that is to weather factors beforehand. Based on the factors and the expected impact of factors together with the weather data during the last 50 years in Seoul region gathered from Korea. Through it, calculated number of month working day of RCA's structural steel work. Studied way that apply to RTPM system.

• Research in Community and Public Health Nursing
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• v.14 no.3
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• pp.457-467
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• 2003

Purpose: This study examined the development and performance of the school health promotion policy guideline that is applicable to Korean school health. Methods: 1. The WHO's guideline was translated into Korean and modified by school health experts 2. A questionnaire was conducted to assess the performance of school health policy on 207 nurses in elementary schools in Seoul and Cheonbuk. Result: The Korean version of the school health promotion policy guidelines were developed including 9 components and 36 checkpoints. Compared to that of WHO, the component 'school nursing teacher' was added and three components were eliminated: 'equitable access to school resources', 'control of helminth', and 'sun protection policy'. The performance degree of first-aid, closure of school in a calamity, and control of HIV/AIDS was very low. The performance degree of a healthy diet, and regular physical examination was quite high. This study was the first that developed the school health promotion policy guideline and examined the performance. Further research is needed to validate the guidelines developed by this study.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.167-176
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• 2008

Vulnerability assessment of power systems is important so as to determine their ability to continue to provide service in case of any unforeseen catastrophic contingency such as power system component failures, communication system failures, human operator error, and natural calamity. An approach towards the development of on-line power system vulnerability assessment is by means of using an artificial neural network(ANN), which is being used successfully in many areas of power systems because of its ability to handle the fusion of multiple sources of data and information. An important consideration when applying ANN in power system vulnerability assessment is the proper selection and dimension reduction of training features. This paper aims to investigate the effect of using various feature extraction methods on the performance of ANN as well as to evaluate and compare the efficiency of the proposed feature extraction method named as neural network weight extraction. For assessing vulnerability of power systems, a vulnerability index based on power system loss is used and considered as the ANN output. To illustrate the effectiveness of ANN considering various feature extraction methods for vulnerability assessment on a large sized power system, it is verified on the IEEE 300-bus test system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.2
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• pp.251-257
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• 2015

Rationality only based on human experience and visuals takes huge toll on nation at the time of disasters. Accordingly, it is required to convert its system into national disaster-managing system based on governmental departments effective cooperation against catastrophic emergencies. Thus, this manuscript rejects empirical model of calamity measures and provides substituting prototype based on u-Gov which utilizes UT service from the developed countries' cases. Moreover, in order to provide nation's administrative services, the paper suggests alternative for politic issues which realizes a new incorporated control towel reflecting policies.