• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.519-526
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• 2010

The construction site for $\bigcirc\bigcirc$ transformer substation was located at a mountain valley. In order to prepare the site, the valley was first filled with crushed rock debris up to 63m. Since the main concern of this project is to minimize differential settlement of the foundation of transformer facilities, dynamic compaction was performed every 7m followed by reinforcement with EMP(Ez-Mud Piling). The EMP is one of bored piling methods, in which a hole is bored by means of air percussion and maintain by injecting Ez-Mud. Then a PHC pile (Pretensioned spun High strength Concrete pile) is embedded and finalized with a hammer. In this study, bearing capacities and long term behavior of a pile installed by EMP were investigated. To achieve these objectives, a series of tests such as static and dynamic load tests were conducted. In addition, a construction quality control standard was proposed based on the test results.

• Journal of the Korean Society for Railway
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• v.18 no.1
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• pp.33-42
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• 2015

The vertical static stiffness of rail pads or baseplate pads, which are important components in rail fastening systems for track safety, is a key factor to determine the total track stiffness and a guideline of quality control in the manufacturing process. The vertical static stiffness can be checked by laboratory testing: test methods are EN 13146-9 and KRS TR 0014, which are widely used in the railway field. In this paper, to correct some problems, namely the preloading step, the unloading level, and the holding time in the loading program in the vertical static stiffness test of EN 13146-9 and KRS TR 0014, domestic and foreign test standards of pads were analyzed and then certain schemes for a vertical static stiffness test were proposed. To assess the reliability of the proposed schemes, the vertical static stiffness tests were performed with 4 pads and the validity of the test results was estimated.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.26 no.3
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• pp.165-171
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• 2020

Maintaining steady and low temperature during distribution process is a key technique to inhibit microbial growth, one of the most important factors in determining the shelf life. It is possible to provide high-quality fresh products to consumers only when precise and adequate temperature control is guaranteed throughout the entire distribution process for fresh seafood. This study investigated the shelf-life of packaged fresh flounder (Paralichthys Olivaceus) in order to learn the feasibility of super-chilled distribution of fresh seafood. To estimate the shelf life, weight, number of bacteria such as E. coli, pH, sensory test and volatile basic nitrogen were investigated. As a result of the study, the difference in shelf life of 6 days at the super-chilling temperature (0±1℃) and 1 day at the general refrigeration temperature (8±2℃) (based on volatile base nitrogen) showed the market possibility of super-chilling distribution. Through additional empirical studies such as packaging methods and economic feasibility, it is expected to promote commercialization of super-chilling containers and packaging system developed in the future and secure customer reliability.

• Journal of Power System Engineering
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• v.17 no.5
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• pp.64-68
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• 2013

One of the water management goals in PEM fuel cell is to avoid flooding and drying in the membrane, therefore the air humidification process is required. In order to increase water removal out of the membrane, the water management system may require the dehumidification process and it also requires a large space for application, moreover the process time is slow. In conformity with this fact, this present study proposes an advanced dynamic fuel cell water management which can be an intermittent optimization control using air flow rate instead of the air humidity as an variable in the optimization process. The results of this study have shown that the membrane flooding and drying can be avoided after being assisted by air velocity controlling method.

• Proceedings of the IEEK Conference
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• 2004.08c
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• pp.600-607
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• 2004

The paper describes the implementation of the video conferencing system using public key infrastructure which is used for user authentication and media stream encryption. Using public key infrastructure, we are able to reinforce the authentication for conference participant and block several malicious hacking while protecting conference control information. The paper shows the implementation of the transportation layer secure protocol in conformity with Korea public key authentication algorithm standard and symmetric key encryption algorithm (RC2, SEED, DES and 3DES) for media stream encryption. The feature of the paper is transportation layer secure protocol that is implemented for protection of information on a user authentication and video conference and the media streaming encryption algorithm also can be envisioned with another block encryption algorithm. The key for media streaming encryption may be safely distributed by the transportation layer secure protocol.

• Journal of the Korean Society of Costume
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• v.50 no.5
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• pp.77-90
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• 2000

The purpose of this study is to disclose the dimension of job characteristic, working place situation. and clothes selection, which are variable on clothes selection, to research the relation of job characteristic, working place situation, and clothes selection and to disclose the feature of consumers by each group in accordance with job characteristic. The follows are summary of this study result : The concept structure of job characteristic is composed by four types. Working place situation related with clothes selection are consisted of five types. Professional women selected clothes in accordance with nine feature. Job characteristic is related with working palace situation and influences on clothes selection. The persons influenced by activity state regarded personality as important when select clothes. The persons influenced by duty state regarded harmony and control as important, instead of, they ignored conformity. People select occupation according to individual feature, so the feature of consumers, working place environment, working place situation are different in accordance with job characteristic, as a result we can find differences in clothes selection suitable for working palace and purchasing.

• Journal of information and communication convergence engineering
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• v.14 no.3
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• pp.191-199
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• 2016

In this study, we investigate the safety requirements and test methods of a radiofrequency stimulator. The main test items include controls of a minimum output, accommodation range, and output parameters that have been known as the safety requirements in conformity with international standards. As the test criteria for controlling the minimum output, an increase or decrease in a unit of 1 mA or 1 V or less was applied to the output amplitude regulator for both continuous and discontinuous control, and the output at the minimum setting was manipulated to not exceed 2% of the maximum setting. For controlling the output parameters, one of the representative test criteria states that the current limit of 250 mA should be equal to or less than 1,500 Hz. Consequently, when applying the radiofrequency stimulator on the human body, we need to ensure that the safety requirements conform to the international standards.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1612-1620
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• 2016

This paper presents the dynamic excitation control of a siphon-turbine coupled pico-hydro powered cage rotor induction generator and load matching for off-grid electricity generation. Through the proposed dual-role of the current-controlled voltage source converter (VSC), acting as static synchronous compensator and load controller, real and reactive power are dynamically controlled in a decoupled manner with a self supported DC-bus. The proposed scheme entails minimal computation for ensuring the rated (set) capacity of real power. The scheme also exhibits fault immunity for protection, thus enabling the effective handling of constant power electrical loads presented by base telecom station towers in remote locations. The performance of the system is evaluated under MATLAB/Simulink and is experimented through a developed hardware prototype. Simulation and experimental results show close conformity and validate the effectiveness of the proposed scheme.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.24 no.3
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• pp.159-165
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• 2018

This review outlines the past and current technology development and research trends on the superchilling technic along with packaging technology such as modified atmosphere packaging. A superchilling technic combined with appropriate packaging technologies such as Modified Atmosphere Packaging is beneficial and promising for fish and meat products in terms of freshness and shelf-life extension although there are many barriers for commercialization such as temperature control throughout supply chain.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.210-211
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• 2022

Pruning is the most important work for the growth and aesthetics of street trees. It is also the most actively conducted maintenance work. However, the specifications, application methods, and cost criteria for pruning have not been systematically established. This has recently caused a lot of confusion in the practice of street tree pruning, such as indiscriminate pruning and lack of construction costs. Therefore, this study clarified the contents of work according to the form of pruning. It added 'aesthetic pruning,' which takes into account design. In addition, It revised equipment not in conformity with the law and excluded personnel necessary for on-site traffic control so that they could be reflected separately. As a result, this study is expected to contribute a lot to securing appropriate construction costs for maintaining street trees.