• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.26-33
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• 1998

The thickness of buried gas pipeline is determined mainly with internal pressure and location factor according to the requirements of ANSI B3l.8. But the stress of buried gas pipeline is determined by not only internal stress but also external loads. The change of burying and environmental conditions, therefore, may result in increasing stress of pipeline. In order to avoid the decrease of safety degree resulting from change of environmental condition, the evaluation of stress level shall be necessary. The reliable equations have been developed for calculating stress of buried pipeline from internal pressure, earth load, vehicle load, ground subsidence. But they are very difficult to understand and use for non-specialist. For easy calculation of non-specialist, the new computer program to calculate stress of buried natural gas pipeline have been developed. The program can calculate maximum stress resulted from earth load, vehicle load, thermal load, four type ground subsidence. The stress is calculated by the equations and extrapolation of the graph resulted from FEM. In this paper, as the series of paper I, the operating method and the functions of the program is explained.

• Archives of design research
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• v.17 no.3
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• pp.413-420
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• 2004

New design method has been required for web designers to grasp the proper emotion, impression, and feeling of a web site and reflect these elements in web design. It is certain that such a new methodology can be a useful design tool, although web designers have only relied on their intuition and experience to induce users to perceive specific emotion of web sites. In this study, Kansei Engineering Type Ⅰ (Nagamachi, 2002 and Park, 2000) method was applied to develop the methodology. One hundred thirty six web sites believed to convey emotions effectively were first selected by recommendation of professional web designers and twenty two web sites were finally chosen and evaluated using questionnaire. The web sites were then objectively and quantitatively assessed by measuring the degree of utilization of the design elements, balance, overall density, and homogeneity. We examined the cause-and-effect between the results of emotional and quantitative analysis by multiple regression and introduced the design methodology based on the examination. The research method and procedures applied to this study would be applicable to design studies related to the emotional inducement.

• Korean Chemical Engineering Research
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• v.57 no.6
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• pp.781-789
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• 2019

There are frequent accidents by chemicals during laboratory experiments and pilot plant and reactor operations. It is necessary to find and comprehend relevant information to prevent accidents before starting synthesis experiments. In the process design stage, reaction information is also necessary to prevent runaway reactions. Although there are various sources available for synthesis information, including the Internet, it takes long time to search and is difficult to choose the right path because the substances used in each synthesis method are different. In order to solve these problems, we propose an intelligent synthetic path search system to help researchers shorten the search time for synthetic paths and identify hazardous intermediates that may exist on paths. The system proposed in this study automatically updates the database by collecting information existing on the Internet through Web scraping and crawling using Selenium, a Python package. Based on the depth-first search, the path search performs searches based on the target substance, distinguishes hazardous chemical grades and yields, etc., and suggests all synthetic paths within a defined limit of path steps. For the benefit of each research institution, researchers can register their private data and expand the database according to the format type. The system is being released as open source for free use. The system is expected to find a safer way and help prevent accidents by supporting researchers referring to the suggested paths.

• Composites Research
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• v.32 no.1
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• pp.21-28
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• 2019

Recently, according to environmental regulations, the automobile industry has been conducting various research on the use of composite materials to increase fuel efficiency. However, there has not been much research on lightweight chassis components. Therefore, in this research, the purpose of this study is to apply composite materials to the sub-frame of chassis components to achieve equivalent levels of stiffness, strength, NVH performance and 50% lightweight compared to the steel sub-frame. First, the Natural frequency of steel and composite specimens was compared to the damping characteristics of composite materials. Then, in this study, the Lay-up Sequence was derived to maximize the stiffness and strength of the sub-frame by applying composite materials. And this lay-up Sequence is proposed to avoid heat shrinkage due to curing during manufacturing. This process was designed based on a FEM structural analysis, and a Natural frequency and frequency response function graph was confirmed based on a modal analysis. The prototype type composite sub-frame was manufactured based on the design and the F.E.M analysis was verified through a modal experiment. Furthermore, it was fitted to the actual vehicle to verify the natural frequency and the indoor noise vibration response, including idling and road noise. This result was confirmed to be equivalent to the steel sub-frame. Finally, the composite sub-frame weight was confirmed to be about 50% of the steel sub-frame.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.3
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• pp.201-207
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• 2021

Deep learning, a type of machine learning, performs learning while changing the weights as it progresses through each learning process. Tensor Flow and Keras provide the results of the end of the learning in graph form. Thus, If an error occurs, the result must be discarded. Consequently, existing technologies provide a function to roll back learning results, but the rollback function is limited to results up to five times. Moreover, they applied the concept of MLOps to track the deep learning process, but no rollback capability is provided. In this paper, we construct a system that manages the intermediate value of the learning process by blockchain to record the intermediate learning process and can rollback in the event of an error. To perform the functions of blockchain, the deep learning process and the rollback of learning results are designed to work by writing Smart Contracts. Performance evaluation shows that, when evaluating the rollback function of the existing deep learning method, the proposed method has a 100% recovery rate, compared to the existing technique, which reduces the recovery rate after 6 times, down to 10% when 50 times. In addition, when using Smart Contract in Ethereum blockchain, it is confirmed that 1.57 million won is continuously consumed per block creation.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.2
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• pp.81-89
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• 2022

Purpose: Wireless endodontic handpieces (WEH) are widely used in dental clinics due to their convenience and portability. This study aimed to compare the vibration magnitudes and patterns generated by five WEH. Materials and Methods: Vibration acceleration of five WEH (X-Smart IQ, E connect S, Endo A Class, ENDOIT, and TRAUS ENDO) in the rotary and reciprocating motion was measured with accelerometer The average vibration acceleration was analyzed using the t-test, Welch's ANOVA test, and Dunnett T3 test at P < 0.05. Results: In all WEH, the average vibration acceleration in reciprocating motion was significantly higher than that in rotary motion (P < 0.001). In rotary motion, repeated vibration graphs of constant amplitude were obtained without sudden changes in the magnitude of vibration, and the average vibration acceleration value was high in the order of X Smart IQ, Endo A Class, ENDOIT, E Connect S, and TRAUS ENDO (P < 0.001), there was no statistically significant difference between X Smart IQ and Endo A Class. In reciprocating motion, a vibration graph was obtained in which large amplitude peaks appear at specific points within one cycle are repeated. The average vibration acceleration value was highest in the order of X Smart IQ, E Connect S, Endo A class, ENDOIT, and TRAUS ENDO (P < 0.001). Conclusion: Regardless of the type of WEH, greater vibration occurred in the reciprocating motion than in the rotary motion (P < 0.001). In the reciprocating motion, there was a difference in vibration for all handpieces (P < 0.001).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.1
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• pp.44-49
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• 2022

In this paper, we investigated current (I)- and voltage (V)-sweeping properties in a double-stack structure, Ge₂Sb₂Te₅/Ti/W-doped Ge₈Sb₂Te₁₁, a candidate medium for applications to multilevel phase-change memory. 200-nm-thick and W-doped Ge₂Sb₂Te₅ and W-doped Ge₈Sb₂Te₁₁ films were deposited on p-type Si(100) substrate using magnetron sputtering system, and the sheet resistance was measured using 4 point-probe method. The sheet resistance of amorphous-phase W-doped Ge₈Sb₂Te₁₁ film was about 1 order larger than that of Ge₂Sb₂Te₅ film. The I- and V-sweeping properties were measured using sourcemeter, pulse generator, and digital multimeter. The speed of amorphous-to-multilevel crystallization was evaluated from a graph of resistance vs. pulse duration (t) at a fixed applied voltage (12 V). All the double-stack cells exhibited a two-step phase change process with the multilevel memory states of high-middle-low resistance (HR-MR-LR). In particular, the stable MR state is required to guarantee the reliability of the multilevel phase-change memory. For the Ge₂Sb₂Te₅ (150 nm)/Ti (20 nm)/W-Ge₈Sb₂Te₁₁ (50 nm), the phase transformations of HR→MR and MR→LR were observed at t<30ns and t<65ns, respectively. We believe that a high speed and stable multilevel phase-change memory can be optimized by the double-stack structure of proper Ge-Sb-Te films separated by a barrier metal (Ti).

• Science of Emotion and Sensibility
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• v.25 no.3
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• pp.77-90
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• 2022

This study seeks to develop a stretch sensor for measuring the wrist movements of people using fishing lures. In order to confirm wrist movement, a stretch sensor was attached to the wrist band, and measurements of the dorsiflexion, plantar flexion, and fishing landing motion were measured using a scale to gauge factor, tensile strength, and elongation recovery rate. A conductive sensor using CNT dispersion was developed and applied to the E-band under the same conditions. A total of 15 sensors of the same size and five types of impregnation once, twice, and three times each were used to measure the gauge factor using UTM. The sensor that was impregnated twice had the best gauge rate, and the prototypes were manufactured with three sensors with high gauge rates and tensile strength. The results of the operation test conducted by connecting to the Arduino showed that Sample 1, which had the highest tensile strength and gauge factor, had a stable graph wavelength in three operations. Samples 2 and 3 showed stable wavelengths in the dorsiflexion and the plantar flexion; however, signal noise appeared in the fishing landing motion. This showed stable wavelengths in the two motions, but the wavelengths of the graphs differ depending on the tensile strength and gauge factor in the fishing landing motion. As a result, it was possible to identify the conditions necessary for manufacturing a stretch sensor for measuring wrist movement. This study will contribute to the development of smart wearable products for lure fishing.

• The Journal of the Convergence on Culture Technology
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• v.9 no.1
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• pp.691-695
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• 2023

Currently, the utilization of measurement results of the automated measurement system is very low and is at the level of providing only fragmentary measurement results. In this study, we are going to study a structure behavior analysis 3D display system with high precision and reliability for automated measurement data obtained by constructing big data by transmitting massive data values measured in real time to the cloud and using a Python-based algorithm. As a result of the study, as a system that can evaluate the behavior of a structure to a manager in real time, it provides analysis data in real time without significant restrictions regardless of the type of measurement data and sensor, and derived it as a 3D display. In addition, it was analyzed that the manager could grasp the behavior graph of the structure in real time and more easily judge the derivation of the weak part of the structure through data analysis. In the future, by analyzing the behavior of structures in three dimensions using past and present data, it is expected that more effective measurement results can be obtained in terms of repair, reinforcement, and maintenance of realistic structures.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.37 no.1
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• pp.88-93
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• 2024

To evaluate the possibility as a multi-level memory medium for the Ge₂Sb₂Te₅/TiN/W-doped Ge₂Sb₂Te₅ cell structure, the crystallization rate and stabilization characteristics according to voltage (V)- and current (I)- pulse sweeping were investigated. In the cell structures prepared by a magnetron sputtering system on a p-type Si (100) substrate, the Ge₂Sb₂Te₅ and W-doped Ge₂Sb₂Te₅ thin films were separated by a barrier metal, TiN, and the individual thicknesses were varied, but the total thickness was fixed at 200 nm. All cell structures exhibited relatively stable multi-level states of high-middle-low resistance (HR-MR-LR), which guarantee the reliability of the multilevel phase-change random access memory (PRAM). The amorphousto-multilevel crystallization rate was evaluated from a graph of resistance (R) vs. pulse duration (T) obtained by the nanoscaled pulse sweeping at a fixed applied voltage (12 V). For all structures, the phase-change rates of HR→MR and MR→LR were estimated to be approximately t<20 ns and t<40 ns, respectively, and the states were relatively stable. We believe that the doublestack structure of an appropriate Ge-Sb-Te film separated by barrier metal (TiN) can be optimized for high-speed and stable multilevel PRAM.