• Journal of the Korea institute for structural maintenance and inspection
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• 제24권1호
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• pp.16-23
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• 2020

Water pipes are important facilities and consist of pipes of various specifications and materials. The annual average number of earthquakes in Korea is steadily increasing. Therefore, in case of the water pipe, it is estimated necessary to prepare for earthquakes. Damages to the water pipe by the earthquake can cause problems such as water supply and fire suppression, and cause damage to life and property. In Korea, however, it is difficult to find examples of seismic performance evaluation of water pipes based on experimental study. Damage to the water pipes by the earthquake is caused by the displacement-controlled behavior of the ground which is the liquifaction and fault lines. Especially, The damage to the water pipes by the earthquake is concentrated on the joint of the pipe. In particular, piping less than 200mm in diameter was found to be dangerous. Thus, in this study, the seismic and settlement performance of iPVC buried water pipes with fixed joints with a clamp of 150mm was evaluated with a test approach.

• Journal of Korean Philosophical Society
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• 제141권
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• pp.63-84
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• 2017

In the twentieth century Anscombe's 1958 article "Modern Moral Philosophy" argued that duty-based conceptions of morality are conceptually incoherent for they are based on the idea of a "law without a lawgiver". Concepts such as "morally ought", "morally obligated", and "morally right" require a legislator as the source of moral authority. In the past God occupied the role, but systems that dispense with God are lacking the proper foundation for meaningful employment of those concepts. Aristotle's virtue ethics can do so without appealing to any such lawgiver, and ground morality in the well being of human moral agents. Therefore Anscombe recommends a return to the eudaimonistic ethical theories of the ancients as secular approaches. Eudaimonia is a central concept in Aristotelian ethics, along with the terms "aret?"(translated as virtue or excellence) and "phronesis"(translated as practical wisdom). In Aristotle's works, eudaimonia was used as the term for the highest human good, and so it is the aim of practical philosophy to consider what it really is and how it can be achieved. Eudaimonia is a Greek word commonly translated as well-being, happiness, welfare or "human flourishing". As Aristotle points out, saying that eudaimon life is a life which is objectively desirable, and means living well. Everyone wants to be eudaimon. And everyone agrees that being eudaimon is related to faring well and to an individual's well being. But the really difficult question is to specify just what sort of activities enable one to live well. Aristotle says that the eudaimon life is one of "virtuous activity in accordance with reason," this is a necessary condition of eudaimonia, the pleasure accompanied by virtuous activities is a sufficient condition. Hence we have a more accurate translation of eudaimonia with a review the practical meaning of eudaimonia, and the correlation between eudaimonia and arete, pleasure.

• Journal of the Korean Recycled Construction Resources Institute
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• 제9권3호
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• pp.268-275
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• 2021

The three factors that determine the strength of concrete are the strength of cement paste, aggregate and ITZ(Interfacial Transition Zone) between aggregate and cement paste. Out of these, the strength of ITZ is the most vulnerable. ITZ is formed in 10~50㎛, the ratio of calcium hydroxide is high, and CSH appears low ratio. A high calcium hydroxide ratio causes a decrease in the bond strength of ITZ. ITZ is due to further weak area. The problem of ITZ appears as a more disadvantageous factor when it used lightweight aggregate. The previous study of ITZ properties have measured interfacial toughness, identified influencing factors ITZ, and it progressed SEM and XRD analysis on cement matrix without using coarse aggregates. also it was identified microstructure using EMPA-BSE equipment. However, in previous studies, it is difficult to understand the microstructure and mechanical properties. Therefore, in this study, a method of measuring electrical resistance using EIS(Electrochemical Impedance Spectroscopy) measuring equipment was adopted to identify the ITZ between natural aggregate and lightweight aggregate, and it was tested the change of ITZ by surface coating of lightweight aggregate with ground granulated blast furnace slag. As a result, the compressive strength of natural aggregate and lightweight aggregate appear high strength of natural aggregate with high density, surface coating lightweight aggregate appear strength higher than natural aggregate. The electrical resistivity of ITZ according to the aggregate appeared difference.

• Journal of the Korean Geotechnical Society
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• 제37권9호
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• pp.5-12
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• 2021

Pseudo-static slope stability analysis method is widely used in engineering practice to calculate the seismic factor of safety of slope subjected to earthquake ground motions. Although the dynamic analysis method is well recognized to have the primary advantage of simulating the stress-strain response of soils, it is not often used in practice because of the difficult in estimating the factor of safety. In this study, a procedure which utilizes the dynamic analysis method to extract the transient dynamic factor of safety is devleoped. This method overcomes the major limitation of the pseudo-static method, which uses an empirically determined seismic coefficient to derive the factor of safety. The proposed method is applied to a slope model and the result is compared with that of the pseudo-static method. It is shown that minimum dynamic factor of safety calculated by the dynamic analysis is slightly larger than that determined from the pseudo-static method. It is also demonstrated that the dynamic factor of safety becomes minimum when the horizontal seismic coefficient and horizontal average acceleration are maximum.

• KIPS Transactions on Software and Data Engineering
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• 제8권6호
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• pp.243-250
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• 2019

Because of a moving UAV has a lot of potential/kinetic energy, if the UAV falls to the ground, it may have a lot of impact. Because this can lead to human casualities, in this paper, the population density area on the UAV flight path is defined as a dangerous area. The conventional UAV path flight was a passive form in which a UAV moved in accordance with a path preset by a user before the flight. Some UAVs include safety features such as a obstacle avoidance system during flight. Still, it is difficult to respond to changes in the real-time flight environment. Using public Big Data for UAV path flight can improve response to real-time flight environment changes by enabling detection of dangerous areas and avoidance of the areas. Therefore, in this paper, we propose a method to detect and avoid dangerous areas for UAVs by utilizing the Big Data collected in real-time. If the routh is designated according to the destination by the proposed method, the dangerous area is determined in real-time and the flight is made to the optimal bypass path. In further research, we will study ways to increase the quality satisfaction of the images acquired by flying under the avoidance flight plan.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제20권1호
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• pp.323-328
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• 2019

In order to construct 3D geospatial information about the terrain, current measurement using a total station, remote sensing, GNSS(Global Navigation Satellite System) have been used. However, ground survey and GNSS survey have time and economic disadvantages because they have to be surveyed directly in the field. In case of using aerial photographs and satellite images, these methods have the disadvantage that it is difficult to obtain the three-dimensional shape of the terrain. The terrestrial LiDAR can acquire 3D information of X, Y, Z coordinate and shape obtained by scanning innumerable laser pulses at densely spaced intervals on the surface of the object to be observed at high density, and the processing can also be automated. In this study, terrestrial LiDAR was used to analyze slope displacement. Study area slopes were selected and data were acquired using LiDAR in 2016 and 2017. Data processing has been used to generate slope cross section and slope data, and the overlay analysis of the generated data identifies slope displacements within 0.1 m and suggests the possibility of using slope LiDAR on land to manage slopes. If periodic data acquisition and analysis is performed in the future, the method using the terrestrial lidar will contribute to effective risk slope management.

• Journal of Korean Tunnelling and Underground Space Association
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• 제21권5호
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• pp.689-698
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• 2019

In tunnel excavation by TBMs, a cutterhead, which practically excavates the ground, is an important part directly affecting net penetration rate. Most of the researches on the cutterhead design that have been carried out until now are on the cutter arrangement. It is difficult to find a study for the effect of the scraper installation direction on TBM excavation although same cutterheads except for direction of the scraper are used in Korea. Therefore, this paper shows how the direction of scraper installation affects shield-TBM excavation. Discrete element method was used to identify the effect of scraper installation direction on shield-TBM excavation. When the scraper installation direction was outward, the amount of particles per unit time flowed into the cutter head opening was smaller than when the scraper installation direction was inward, and more loads were applied to the cutterhead.

• The Korean Journal of Archival Studies
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• 제32호
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• pp.45-78
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• 2012

The significance of Presidential Impeachment in 2004 is subject to interpretations in many different contexts, but its nature as its justice was the constitutional trial by the nation's impeachment system. This study set out to compare and analyze the understanding of the event centered around its nature as "an impeachment event as a public activity" and the records related to it. For that purpose, the study attempted to analyze the impeachment event to understand it as a public activity and examined and analyzed the records of the impeachment event in the public domain through personal visit, phone interview, and request of information disclosure based on the analysis results. An impeachment event as a public activity can be understood as an activity carried out by the National Assembly, which is to issue a motion for impeachment under the norms of the nation's impeachment system, and Constitutional Court, which is responsible for impeachment trial, through their unique rights prescribed in the Constitution. The important subjects of such a public activity included the accused president, the acting presidential system created by the motion for impeachment, and the National Election Commission that provided a decisive ground for impeachment. It was confirmed that the records, which are legal requirements, were well created and have been preserved and managed in the public domain. However, it was difficult to conclude that the records of the impeachment event were thoroughly created in terms of content in relation to affairs as they mainly covered the superficial treatment processes and the results of explicit activities. There was, in particular, the absence of records showing the context of activity.

• Journal of the Korean Society of Radiology
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• 제14권7호
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• pp.849-856
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• 2020

In the gamma-ray energy spectrum study, nuclide analysis through energy analysis is very important. High-purity Ge detectors, which are commonly used for gamma-ray energy measurements, are commonly used because of their high energy resolution and relatively high detection efficiency. However, in order to maintain a high energy resolution, the semiconductor detector has a problem in that it is difficult to maintain the original performance if the noise generated from the surrounding environment is not effectively blocked, and the effect of the expensive device is not achieved. Therefore, in this study, ground loop isolator (NEXT-001HDGL) was used to remove the electrical noise generated from the detector. In order to test the effect of improving energy resolution, HPGe detection device newly installed in the proton accelerator KOMAC was used. In the case of gamma-ray energy 2614 keV, the energy resolution was improved from (0.16 ± 0.02) % to (0.11 ± 0.01) %, and in the case of gamma-ray energy 662 keV of 137Cs isotope, the energy resolution was improved from (0.72 ± 0.07) % to (0.27 ± 0.03) %. This result is considered to be very useful for the gamma ray spectrum study using the HPGe detection equipment of KOMAC(Korea Multi-Purpose Accelerator Complex).

• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권6호
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• pp.188-196
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• 2021

For the tactical vehicles operated by the Korean army, the hub-reduction portal axle was applied considering Korea's topographical characteristics. Hub-reduction was applied to a Korean military vehicle to increase the vehicle body to secure ground clearance and improve the driving capability on rough roads, such as unpaved and field land by increasing the torque. The Korean military is operating tactical vehicles after various performance tests, including durability driving, but wheel damage occurred in one of the vehicles operating in the front units. Failure analysis revealed many damaged parts, including the hub, making it difficult to determine the cause. Therefore, an analysis of the failure occurrence mechanism for each damaged part was conducted, which confirmed that the cause of wheel breakage was a hub. Furthermore, the root cause of the hub breakage was a crack due to internal pores and foreign matters. In addition, a realistic improvement plan that can be applied throughout the design, manufacture, and shipping stages was presented using the fishbone diagram analysis. The derived improvement plan was verified through unit performance tests, including CAE and actual vehicle tests, and by reflecting this, the driving safety of Korean tactical vehicles was improved. Finally, it is expected that the proposed method for analyzing the failure occurrence mechanism will be used as reference material when analyzing the quality problems of similar military vehicles in the future.