• Steel and Composite Structures
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• v.51 no.3
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• pp.271-288
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• 2024

The primary objective of this study is to investigate the production and performance characteristics of structural concrete incorporating varying proportions (0%, 25%, and 50% by volume) of pumice stone, as well as aluminum lathe as an additive at 0%, 1%, 2%, and 3%, under fire conditions. The experiment will be conducted over a period of up to 1 hour, at temperatures ranging from 24℃, 200℃, 400℃ and 600℃. For the purpose of this, a total of twelve test samples were manufactured, and then tests of compressive strength (CS), splitting tensile strength (STS), and flexural strength (FS) were performed on these samples.Next, a comparison was made between the obtained values and the influence of temperature. To achieve this objective, the manufactured samples were placed at temperatures of 200℃, 400℃, and 600℃ for a duration of 1 hour, and were subjected to the influence of temperature.These values at 24 ℃ were then contrasted with the CS results obtained from test samples that were subjected to the temperature effect for an hour at 200 ℃, 400 ℃, and 600 ℃. A comprehensive analysis of the test outcomes reveals that the incorporation of aluminum lathe wastes into a mixture results in a significant reduction in the compressive strength of the concrete. As a result of this adjustment, the CS values dropped by 32.93%, 45.70%, and 52.07%, respectively. Furthermore, It was shown that testing the ratios of pumice stone alone resulted in a decrease in CS outcomes. Additionally, it was found that the presence of higher temperatures is clearly the primary factor contributing to the decrease in the strength of concrete. Due to elevated temperatures, the CS values decreased by 19.88%, 28.27%, and 38.61% respectively.After this investigation, an equation that explains the connection between CS and STS was provided through the utilization of the data of the experiments that were carried out.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.157-162
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• 2023

Among the failures of photovoltaic power generation facilities, failures caused by surges account for 20% of the total failure rate, and energy emissions of tens to hundreds [A] during power generation and electrical damage to inverters and connection boards lead to electrical safety accidents. In particular, in the case of lightning, an abnormal voltage is induced in an electric circuit to destroy insulation, and the current flowing at this time causes a fire and acts as a factor that accelerates the deterioration of parts. Due to this action, the problem of electrical safety of solar power generation devices spreading from outside the city center to the inside of the city center such as houses, apartments, and government offices is emerging. Since lightning strikes cause both field-based and conducted electrical interference, this effect increases with increasing cable length or conductor loops. In addition, surge damages not only solar modules, inverters and monitoring devices, but also building facilities, which can eventually cause operational shutdown due to fire of the photovoltaic power generation system and consequent financial loss. Therefore, in this paper, a lightning protection system for solar power generation devices is studied for the purpose of reducing property damage and human casualties due to the increase in fire and electrical safety accidents caused by lightning strikes in photovoltaic power generation systems.

• Journal of Korean Medicine Rehabilitation
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• v.25 no.2
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• pp.111-118
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• 2015

Objectives Through the clinical records of Seungjeongwon Ilgi, we reviewed the usage of Bi-Jeung to know the concept of the word and studied therapeutic strategies for managing Bi-Jeung. Methods We investigated the clinical records of the mid-Chosun dynasty containing the key word "Bi" from electronic database (Seungjeongwon Ilgi). Results Of 4,039 records, 249 articles thought to have medicinal value were lastly selected. We subdivided the cases into 13 categories according to time, the connection of contents and the change of associated symptoms. "Bi" was not used alone but used in combination with body parts or other symptoms. Etiological causes of "Bi" involved dampness, phlegm, fire, heat and qi disorders. We suggested that "Bi" of the mid-Chosun dynasty meant a symptom group mainly of sensory impairment and additionally pain or motor disturbance. Among the 22 herbal medicine formulas used, 15 were based on internal medical pattern identifications and 7 were symptomatic treatments. Acupuncture and moxibustion therapy were primarily applied to adjacent acupoints. In addition, External therapies were used together, such as washing therapy, plaster therapy, cupping therapy and thermotherapy. Conclusions "Bi" principally indicated sensory impairment on limbs and the main etiological cause was considered to be dampness. Herbal medicine, acupuncture, moxibustion and external therapies were used to cure Bi-Jeung.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.10-17
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• 2021

This paper presents the robust design of each component used in the development of an induction bolt heating system for dismantling the high-temperature high-pressure casing heating bolts of turbines in power plants. The induction bolt heating system comprises seven assemblies, namely AC breaker, AC filter, inverter, transformer, work coil, cable, and CT/PT. For each of these assemblies, the various failure modes are identified by the failure mode and effects analysis (FMEA) method, and the causes and effects of these failure modes are presented. In addition, the risk priority numbers are deduced for the individual parts. To ensure robust design, the insulated-gate bipolar transistor (IGBT), switched-mode power supply (SMPS), C/T (adjusting current), capacitor, and coupling are selected. The IGBT is changed to a field-effect transistor (FET) to enhance the voltage applied to the induction heating system, and a dual-safety device is added to the SMPS. For C/T (adjusting current), the turns ratio is adjusted to ensure an appropriate amount of induced current. The capacitor is replaced by a product with heat resistance and durability; further, coupling with a water-resistant structure is improved such that the connecting parts are not easily destroyed. The ground connection is chosen for management priority.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.56-62
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• 2018

The bus bar is an electrical connection widely used for the power supply of skyscrapers and power distribution and industrial equipment electrical panels in industrial plants. There are various materials to be considered in the design of the bus bar, such as material based on the use environment, the sectional area according to the power capacity, the length of the surface circumference, and the tightening method. Even with a bus bar manufactured to a size of sufficient power capacity in the design, if the actual tightening is incorrect, it may lead to fire due to deterioration. For these reasons, a variety of research on the temperature rise of the electrical contact point has continued. However, the temperature rise of the contacts is a consequence of the result, not a direct cause. In this paper, the influence of contact resistance on the fastening force and the overlapping section of the bus bar are investigated by measuring the change in resistance from building the specimen. A total of eight bus bar specimens were manufactured and measured. Resistance was measured by varying the clamping force and the interval between overlapping sections when the specimens were crossed. We propose a safe power connection model by analyzing the contribution of these factors to the actual contact resistance change.

• Journal of Korean Theatre Studies Association
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• no.40
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• pp.207-237
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• 2010

Concentrating on the birth, life, and death of the Living Theatre, almost half a century avant-garde group, the primary purpose of this study at large is to explore its counter-cultural philosophy. While taking a chronological form adapting the biological order, the paper focuses on the troupe's productions: , , , , and . Through out these productions the philosophy of the Living Theatre seemed to included communal, anti-intellectual, politically radical, generally Utopian, and proselytizers for sexual freedom. The history of the Living Theatre interestingly parallels the history of the Beck's theatre in occupation and shut down. The first New York theatre was closed by fire inspectors for instance. The second theatre was declared unsafe, and locked up by the Building Department. The third theatre was seized by the IRS, consequently shut down. In 1984, after more than 25years from the third building, the Living Theatre settled once again on East Third Street in Manhattan. The theatre was however evacuated by the New York City Fire Department in 1993 and once more took to the road. With these struggles, the Becks' profound aspiration of the counter-cultural insurgency came to harden as strong as 'iron' in some ways. With the outstanding components of counter-cultural philosophy and style, the Living Theatre, in the course of the transformation, absorbed and then reflected virtually every phase for the Living Theatre were vehicles for more than just aesthetics. The group seemed to propagandize its beliefs rather performing productions. Accordingly, both on and off-stage action of the Living Theatre caused great controversy either through political activism of individual members or through the unconventional collective life style. No avant-garde theatre company was more emblematic of the rebellious spirit of the sixties than the Living Theatre. Like the first great transformation, the Becks' encounter, their personal values and the form of theatre they created had blended 'so inextricably that the vitality of each was dependent on the other.' The Becks always urged unity and harmony at all levels of human life, but not at any price. The anticapitalist ideal inspired the Becks to promote a politically motivated campaign throughout their productions. They believed the revolution is desirable but in the state of non-violence and the expansion of human consciousness. Julian Beck's gravestone identifies his as pet, painter, actor, and anarchist. The Living Theatre was a 'small umbrella' under which the Becks and its members could breath and unfold their dream on stage or in the street.

• Journal of the Korea Convergence Society
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• v.8 no.5
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• pp.275-285
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• 2017

The architectural site exists in the context of the surrounding environment as the background of architectural design, and the architecture exists in the connection between the site and the surrounding environment therefore, the plan of the building starts from the analysis of the site, and its consequences too meaning can be found in the relation with the surrounding environment. Ironically, however, there are no direct papers describing site analysis with this meaning. Therefore, this paper categorizes the site analysis items around the four environments of Land, Water, Fire, and Wind that constitute the environment of the ecosystem, furthermore, in order to apply the result of the fusion information to the architectural design by synthesizing the organic correlation between the inside and the surrounding environment, i created the '9sectors system', which is a combination of 'horizontal 3 and vertical 3' to provide a more rational and efficient architectural plan. Through the progress of the project using this system, it is considered that it is a more applicable method of the site analysis data than the existing site analysis method.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.28 no.5
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• pp.491-496
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• 2015

The headed studs used extensively for steel-composite construction are specified as SS400 in the current Korean Standard specification considering the welding condition. And the corresponding equation for the shear force calculation is limited for the use of compression strength of concrete below $300kgf/cm^2$. However, it is expected that the high strengthening and precasting of both steel and concrete due to the necessity of shear connector or other connecting material for the combination of steel and concrete. Therefore, the experimental results obtained during the development process of high strength stud for the connection of high strength concrete and the steel member are reported in this paper. Also the effectiveness of newly developed shear connector using pipe(pipe stud) to increase the stiffness of a stud is verified by comparing both the stiffness and the strength with common stud bolt through the welding ability, mechanical characteristics and experimental investigation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.398-407
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• 2021

Firefighters (who are responsible for people's safety) have one of the jobs that are expected to have problems due to aging in the workforce. An increase in the average age of firefighters can lead to serious social problems. The aim of this study is to survey firefighters in Jeollanam-do about their awareness of aging in firefighters, and to propose a plan to prepare them for aging through investigation and analysis of work problems that may occur due to an aging workforce. The survey shows that the higher the age group, the higher the awareness of aging firefighters, and the higher the total work experience and internal/external work experience, the higher the awareness of aging. As a plan to solve various problems that may arise from aging in firefighters, regular operation of physical fitness promotion programs, field work, job rotation, and managerial measures (such as a change of position to an administrative department) are prepared, and drone or robot technology is used. These solutions include the introduction of applied high-tech technologies to firefighting activities, establishment of retirement management policies, and preparation of plans to revitalize the connection to private employment. In order to maximize the applicability of the field, government institutional plans and preparations are essential.

• Journal of The Korean Astronomical Society
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• v.50 no.6
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• pp.167-178
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• 2017

We present a study of the inexplicit connection between radio jet activity and ${\gamma}$-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two ${\gamma}$-ray outbursts (in November 2013 and March 2015) can be seen in ${\gamma}$-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of $411{\pm}85$ days, $352{\pm}79$ days, $310{\pm}57$ days, and $283{\pm}55$ days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths $B{\sim}2{\mu}T$ and electron Lorentz factors ${\gamma}$ ~ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale ${\tau}$ scales with frequency ${\nu}$ like ${\tau}{\propto}{\nu}^{-0.2}$. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the ${\gamma}$-ray outbursts. The spectral evolution is consistent with the 'generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second ${\gamma}$-ray event indicate that this ${\gamma}$-ray outburst might be an 'orphan' flare powered by the 'ring of fire' mechanism.