• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.406-418
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• 2020

When developing weapons systems, it is important to implement the functions and performance of equipment suitable for development purposes, but it is very important to ensure that the equipment is capable of operating without any vacuum with reliability after development. Therefore, various activities are carried out to enhance reliability of equipment. Reliability is enhanced by using high-specification parts in development, reliability verification through analysis, and testing using development prototypes to reinforce and improve the parts that are lacking in equipment. However, recently, development schedules are shortened due to rapidly changing external conditions and technologies, and there are cases where sufficient reliability growth activities were not carried out due to problems such as cost. Examples are projects that perform reliability activities only in analytical methods (reliability, FMECA). In this paper, analyzing and testing methods for analysis and testing were carried out on the same equipment through FMECA and super-accelerated life test, the contents of reliability growth activity were derived, the results of design change/review were accordingly compared, the differences between the two methods were analyzed, and measures were proposed to strengthen reliable growth activities. It was concluded that reliable growth activities through analysis from the beginning of development and reliable growth activities through testing should be carried out at the completion of initial prototype production.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.12
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• pp.1301-1307
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• 2011

Electrosurgical knee wand (EKW) is a high-frequency thermocautery instrument and is often used for coagulation, ablation, excision, and extirpation of knee ligaments and tissues. In order to maximize the success rate, ease, and safety of knee surgery using EKW and radiofrequency ablation, it is necessary to ensure that the EKW selectively approaches the lesion with utmost accuracy and safety. The key feature of this instrument is its excellent maneuverability. Hence, the authors constructed a tensile spring model based on a shape memory alloy (SMA), which exhibits the shape memory effect. This model can be used in knee surgery as it is considered the most biocompatible femorotibial surgical actuator. The changes in external temperature with current and the thermoelectric characteristics of the SMA were investigated. The relationship between the restoring force and the typical stroke (TS) in response to the conditions in the SMA tensile spring design were evaluated. In conclusion, as the diameter of the SMA tensile spring decreased, the maximum temperature increased. The strain in the actuator caused a stable and proportional increase in the force and induced current for up to 15s, but this increase became very unstable after 30s. Moreover, the relationship between the current and the TS was more stable than that between the current and the restoring force.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.46-55
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• 2021

Concrete structures can cause various problems as the number of common years increases when exposed to external extreme climate conditions. Among these problems, freezing and thawing occur due to the action of extreme climate factors such as heavy rain and heavy snow, which have become the most problematic in recent years. In this study, we present a rapid freezing and thawing test method of concrete in the air, referring to KS F 2456, as Seoul exhibits very dry weather during the period of freezing and thawing. Concrete test specimens and RC beams were fabricated to perform rapid freezing and thawing of 0, 100, 200, and 300 cycles, and the performance evaluation confirmed the degradation of each subject in material and member units. The design strength of 24 MPa, which performs rapid freezing and thawing in the air up to 300 cycles, decreases by 5.24 MPa (21%), and as rapid freezing and thawing in the air increases the stress burden on reinforced concrete bending members, reducing the energy absorption (dissipation) ability of structures due to earthquakes.

• Journal of Korea Trade
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• v.24 no.6
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• pp.135-156
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• 2020

Purpose - This study investigates whether the internationalization process of traditional industry firms can be categorized as born global, early internationalization, or gradual internationalization, and examines what factors promote internationalization in traditional industries using a case study of two firms, one each in China and Korea. Design/methodology - This study elects to use case study methodology to determine the "how" and "why" of internationalization process of traditional industry firms. Taking into consideration that factors that impact the internationalization process of firms are diverse and unclear in terms of causality, this study utilizes exploratory case study methodology. This research performs a comparative two-case study of two firms in traditional industries, one each in China and Korea, to examine similarities and differences of study subjects in order to improve the validity and suitability of research results. Findings - The findings of this research are as follows: First, traditional industries are more likely go through early and rapid internationalization rather than being born global; born globals are far more likely to appear in high tech industries. Second, the internationalization process of companies that go through early and rapid internationalization differs from what is indicated by traditional internationalization theories, and are not limited by factors like psychological distance and lack of experiential knowledge. Third, international entrepreneurship, international market orientation, and imitation and learning are important internal driving factors for early and rapid internationalization. Fourth, conditions within the domestic market, policy support from the government, and pilot effect from industry leaders are external driving factors for early and rapid internationalization. Originality/value - This study shows that the internationalization process of traditional industry firms is more likely to be early and rapid internationalization rather than being born global and suggests answers to why this may be the case. In addition, through an examination of case studies, it reveals that the internationalization process of traditional industry firms that undergo early and rapid internationalization is different from traditional internationalization theory, in that they are not limited by the lack of psychological proximity and empirical knowledge, and are driven by international entrepreneurship, international market orientation, imitation and learning, competitive pressure within the domestic market, government's policy support, and the pilot effect of industry leaders. Therefore, this study contributes to literature by expanding the scope of application of born global theory to traditional industries, making born global theory more generalizable and identifying driving factors to internationalization of traditional industry firms.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.5
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• pp.100-110
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• 2015

With the trend for the construction of barrier-free living environments in accordance with the ever-increasing external activity of the aging population, multi-culture families and socially disadvantaged, there is also a demand for the facilities improvement at parks for their convenience of use. This study analyzed the possibility of Barrier-Free Certification of an existing open space and defined its prototype renovation plan. This study is intended to help develop Borame Park into a barrier-free park by securing a barrier-free line of movement linking the major facilities sites within the park, improving park facilities lest there should be inconvenience in the use of the major facilities, and a guidance system convenient for use by physically and mentally impaired people. The significance of this study lies in the fact that it diagnosed the possibility of the BF Certification of existing urban parks and established a barrier-free park, which is easy for anyone to use. In the course of doing research on this, this study was able to discover the limitations of the BF Certification system, and its related tasks to be solved in the future as follows: The first thing this study shows is that there is a lack of understanding and awareness of the BF Certification system. Basically, there is a need for giving consideration to the development of a barrier-free living environment from the planning and design phase of a park, but in actuality, an examination of the certification is undertaken at the time of the completion of design and construction, which causes a large loss both time-wise and economically. Second, as evaluative items for the BF Certification of a park, applied are detailed evaluation items that fail to reflect the characteristics of an outdoor space whose natural constraints are large, such as geographical highs and lows and existing trees, plants, etc. Third, guidelines for establishment of a barrier-free park must be created in the light of the locational conditions of the park, followed by improvements of its BF Certification evaluation items.

• Korean Chemical Engineering Research
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• v.60 no.2
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• pp.249-254
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• 2022

With the rapid advance of the semiconductor and Information and communication technologies, remote environment monitoring technology, which can detect and analyze surrounding environmental conditions with various types of sensors and wireless communication technologies, is also drawing attention. However, since the conventional remote environmental monitoring systems require external power supplies, it causes time and space limitations on comfortable usage. In this study, we proposed the concept of the self-powered remote environmental monitoring system by supplying the power with the levitation-electromagnetic generator (L-EMG), which is rationally designed to effectively harvest biomechanical energy in consideration of the mechanical characteristics of biomechanical energy. In this regard, the proposed L-EMG is designed to effectively respond to the external vibration with the movable center magnet considering the mechanical characteristics of the biomechanical energy, such as relatively low-frequency and high amplitude of vibration. Hence the L-EMG based on the fragile force equilibrium can generate high-quality electrical energy to supply power. Additionally, the environmental detective sensor and wireless transmission module are composed of the micro control unit (MCU) to minimize the required power for electronic device operation by applying the sleep mode, resulting in the extension of operation time. Finally, in order to maximize user convenience, a mobile phone application was built to enable easy monitoring of the surrounding environment. Thus, the proposed concept not only verifies the possibility of establishing the self-powered remote environmental monitoring system using biomechanical energy but further suggests a design guideline.

• The Journal of Engineering Geology
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• v.28 no.3
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• pp.475-488
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• 2018

This study evaluates geothermal system efficiency in terms of input power and heat exchange volume on the heat-source and load sides, by applying a combined open-closed type loop system comprising a geothermal system and a groundwater well to a cultivation site. In addition, this study analyzes the effects of heating and cooling for a complex geothermal system, by evaluating the temperatures of an external site and a cultivation site during operation. During cooling operations the heat exchange volume on the heat source side, average 90.0kW/h for an open type system with an input of 235L/minute groundwater, and 40.1kW/h for a closed type system with an input of 85L/minute circulating water, for a total average heat exchange volume of 130.1kW/h. The actual heat exchange volume delivered on the load side averages 110.4kW/h. The average EER by analysis of the geothermal system's cooling efficiency is 5.63. During heating operation analysis, the heat exchange volume on the heat source side, average 60.4kW/h in an open type system with an input of 266L/minute groundwater, and 22.4kW/h in closed type system with an input of 86L/minute circulating water, for a total average heat exchange volume of 82.9kW/h. The actual heat exchange volume delivered on the load side averages 112.0kW/h in our analysis. The average COP determined by analysis of the geothermal system's heating efficiency is 3.92. Aa a result of the tradeoff between the outside temperature and the inside temperature of the production facility and comparing the facility design with a combined well and open-closed loops geothermal(CWG) system, we determine that the 30RT-volume CWG system temperature are lower by $3.4^{\circ}C$, $6.8^{\circ}C$, $10.1^{\circ}C$ and $13.4^{\circ}C$ for ouside temperature is of $20^{\circ}C$, $25^{\circ}C$, $30^{\circ}C$ and $35^{\circ}C$, respectively. Based on these results, a summer cooling effect of about $10^{\circ}C$ is expected relative to a facility without a CWG system as the outside temperature is generally ${\geq}30^{\circ}C$. Our results suggest that a complex geothermal system provides improvement under a variety of conditions even when heating conditions in winter are considered. Thus It is expected that the heating-cooling tradeoffs of complex geothermal system are improved by using water screen.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.152-161
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• 2023

In general, large-capacity hydrogen storage vessels, typically in the form of vertical cylindrical vessels, are constructed using steel materials. These vessels are anchored to foundation slabs that are specially designed to suit the environmental conditions. This anchoring method involves pre-installed anchors on top of the concrete foundation slab. However, it's important to note that such a design can result in concentrated stresses at the anchoring points when external forces, such as seismic events, are at play. This may lead to potential structural damage due to anchor and concrete damage. For this reason, in this study, it selected an vertical hydrogen storage vessel based on site observations and created a 3D finite element model. Artificial seismic motions made following the procedures specified in ICC-ES AC 156, as well as domestic recorded earthquakes with a magnitude greater than 5.0, were applied to analyze the structural behavior and performance of the target structures. Conducting experiments on a structure built to actual scale would be ideal, but due to practical constraints, it proved challenging to execute. Therefore, it opted for an analytical approach to assess the safety of the target structure. Regarding the structural response characteristics, the acceleration induced by seismic motion was observed to amplify by approximately ten times compared to the input seismic motions. Additionally, there was a tendency for a decrease in amplification as the response acceleration was transmitted to the point where the centre of gravity is located. For the vulnerable components, specifically the sub-system (support columns and anchorages), the stress levels were found to satisfy the allowable stress criteria. However, the concrete's tensile strength exhibited only about a 5% margin of safety compared to the allowable stress. This indicates the need for mitigation strategies in addressing these concerns. Based on the research findings presented in this paper, it is anticipated that predictable load information for the design of storage vessels required for future shaking table tests will be provided.

• Journal of IKEEE
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• v.23 no.4
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• pp.1461-1464
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• 2019

In this paper, we propose the development of embedded board for integrated radiation exposure protection fireman's life-saving alarm capable of location tracking and radiation measurement. The proposed techniques consist of signal processing unit, communication unit, power unit, main control unit. Signal processing units apply shielding design, noise reduction technology and electromagnetic wave subtraction technology. The communication unit is designed to communicate using the wifi method. In the main control unit, power consumption is reduced to a minimum, and a high performance system is formed through small, high density and low heat generation. The proposed techniques are equipment operated by exposure to poor conditions, such as disaster and fire sites, so they are designed and manufactured for external appearance considering waterproof and thermal endurance. The proposed techniques were tested by an authorized testing agency to determine the effectiveness of embedded board. The waterproof grade has achieved the IP67 rating, which can maintain stable performance even when flooded with water at the disaster site due to the nature of the fireman's equipment. The operating temperature was measured in the range of -10℃ to 50℃ to cope with a wide range of environmental changes at the disaster site. The battery life was measured to be available 144 hours after a single charge to cope with emergency disasters such as a collapse accident. The maximum communication distance, including the PCB, was measured to operate at 54.2 meters, a range wider than the existing 50 meters, at a straight line with the command-and-control vehicle in the event of a disaster. Therefore, the effectiveness of embedded board for embedded board for integrated radiation exposure protection fireman's life-saving alarm has been demonstrated.

• Trans-
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• v.3
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• pp.55-86
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• 2017

This study begins with the necessity of the concept of reincarnation of film media and the inclusion of specific tendencies of contemporary films as post - cinema comes. Variable movements around recent films Challenging and experimental films show aesthetics that are difficult to approach with the analysis of classical mise en scene and montage. In this way, I review the dispositif proposed by Martin in films that are puzzling to criticize with the classical conceptual framework. This is because the concept of dispositive is a conceptual pile that extends more than a mise en scene and a montage. Dispositif films tend to be non-reproducible and non-narrative, but not all non-narrativef tendencies are dispositif films. Only the dispositif film is included in the flow. Dispositif movement has increased dramatically in the modern environment on which digital technology is based, but it is not a tendency to be found in any particular age. The movement has been detected in classical films, and the dispositif tendency has continued to exist in avant-garde films in the 1920s and some modernist films. First, for clear conceptualization of cinematic dispositif, this study examines the sources of dispositif debates that are being introduced into film theory today. In this process, the theory of Jean Louis Baudry, Michel Foucault, Agamben, Flusser, and Deleuze will help. The concept of dispositif was discussed by several scholars, including Baudry and Foucault, and today the notion of dispositif is defined across all these definitions. However, these various discussions are distinctly different from the cinematic dispositif or dispositif films that Martin advocates. Martin's proposed concept reminds us of the fundamentals of cinematic aesthetics that have distinguished between the mise-en-scene and the montage. And it will be able to reconsider those concepts and make it possible to view a thing a new light or create new films. The basic implications of dispositif are apparatus as devices, disposition and arrangement, the combination of heterogeneity. Thus, if you define a dispositif film in a word, it is a new 'constraint' consisting of rearrangement and arrangement of the heterogeneous elements that make up the conditions of the classical film. In order for something to become a new design, changes must be made in the arrangement and arrangement of the elements, forces, and forces that make up it. Naturally, the elements encompass both internal and external factors. These dispositif films have a variety of possibilities, such as reflection on the archival possibilities and the role of supervision, the reestablishment of active and creative audience, the reason for the film medium, and the ideological reflection. films can also 'network' quickly and easily with other media faster than any medium and create a new 'devised' aesthetic style. And the dispositif film that makes use of this will be a key keyword in reading the films that present the new trend of modern film. Because dispositif are so comprehensive and have a broad implication, there are certainly areas that are difficult to sophisticate. However this will have a positive effect on the future activation of dispositif studies end for end. Dispositif is difficult to elaborate the concept clearly, so it can be accessed from a wide range of dimensions and has theoretically infinite extensibility. At the beginning and end of the 21st century film, the concept of cinematic dispositif will become a decisive factor to dismantle old film aesthetics.