• The Journal of the Convergence on Culture Technology
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• v.3 no.3
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• pp.43-49
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• 2017

The purpose of this study is to study the standardization of the core business process in the chemical manufacturing industry and to establish a production information management system for the purpose of establishing the production information management system that can achieve mid -To be applied. The development methodology for the standardization of the chemical manufacturing information system is applied to the production information management system development methodology (PSDM) that was developed and developed by the Agency for Technology and Information Promotion of Small and Medium Enterprises. The standardization target is the system structure, It is a core business process that becomes a skeleton during construction. In this study, the chemical manufacturing SMEs and related professional IT companies who want to build the production information management system can apply the standardized core business process more effectively to build the system more effectively, and provide ease of installation and reliability to the system, In order to maximize the utilization of processes, follow-up education training and maintenance measures are suggested. Applying the results of this study, it is possible to eliminate the unreasonable elements of the production process, improve the quality of production product, and reduce production cost.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.421-427
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• 2014

Most of the structure of the real world is influenced under dynamic loads. However, when structure analysis and the structural optimization is performed, it is assumed that the static load acts on structure. When considering the actual load of dynamic loads in order to take into account a variety of loads, computational resources and time becomes a big burden in terms of cost. However, considering only the simple static load condition is not preferable for structural safety. For this reason, a lot of studies have been conducted trying to compensate this trouble by applying weight factor or replacing dynamic load with the equivalent static load. In this study, structural optimization techniques for structures under dynamic loads is proposed by applying the equivalent static load. From previous study, after determining the positions of equivalent static load based on primary degrees of freedom, the equivalent static load is calculated through the optimization process. In this process, the equivalent static load optimization of previous research is complemented by adding constraints to avoid excessively large load extraction. In numerical examples, dynamic load is applied to the truss structure and the plate. Then, the reliability of the proposed optimization technique is verified by carrying out size optimization with the equivalent static load.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.3
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• pp.421-432
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• 2020

This paper proposes a 2-kW solid-state power amplifier (SSPA) developed by employing power amplifier pallets designed using gallium-nitride high electron mobility transistors, which is used in S-band military radars and to replace existing traveling-wave tube amplifier (TWTA). The SSPA consists of a high-power amplifier module, which combines eight power amplifier pallets, a drive amplifier module, a digital control module, and a power supply unit. First, the amplifier module and component were integrated into a small package to account for space limitations; next, an on-board harmonic filter was fabricated to reject spurious components; and finally, an auto gain control system was designed for various duty ratios because recent military radar systems are all active phase radars using the pulse operation mode. The developed SSPA exhibited a max gain of 48 dB and an output power ranging between 63-63.6 dBm at a frequency band of 3.1 to 3.5 GHz. The auto gain control function showed that the output power is regulated around 63 dBm despite the fluctuation of the input power from 15-20 dBm. Finally, reliability of the developed system was verified through a temperature environment test for nine hours at high (55 ℃) / low (-40℃) temperature profile in accordance with military standard 810. The developed SSPA show better performance such as light weight, high output, high gain, various safety function, low repair cost and short repair time than existing TWTA.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.161-167
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• 2011

Recent popularity in mobile electronics requires higher standard on the mechanical strength of electronic packaging. Thus, the method of soldering between chip and substrate in electronic packaging process is changing from conventional method using intermetallic compound to a new method using organic solderability preservatives (OSP) in order to improve the stability and the reliability of final product. Since current OSPs have several serious problems like thermo-stability during packaging process, however, it is necessary to develop new OSPs having thermo-stability. The main purpose of this study is to develop various thermo-stable OSPs based upon poly(vinyl pyridine-co- methylmethacrylate) and to evaluate their anti-oxidation property protecting Cu pad, thermo-stability and solubility to acid- or alcohol-containing aqueous solution during pos-fluxing. All OSPs showed not only good anti-oxidation property, thermo-stability and solubility but also more advantages like low cost, less odor, and less hygroscopic.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.1
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• pp.15-23
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• 2015

Purpose: This study was investigated consumers' and optometrists' perception about spectacle frame in Busan and Ulsan to find on the right progress direction for conversion of spectacle frame into medical devices. Methods: 137 consumers surveyed in Busan and Ulsan and 100 optometrist surveyed in 'Busan continuing education of optometrist' filled in a questionnaire, then we compared and analyzed the results. Results: The 79% (108 people) of consumers and 94% (94 people) of optometrists agreed to conversion into medical devices of spectacle frame. The reason was shown that the consumer expected to improve the optometrist reliability and the optometrist expected to improve the optometrist professionalism. While, the 21% (29 people) consumer and 6% (6 people) optometrist opposed to conversion of spectacle frame into medical devices. The reason was revealed that the consumers were concerned about increase of medical insurance cost and the optometrists were concerned about that the spectacle frames can also be sold by medical device stores, not only by optical shops. Conclusions: The result of the survey was shown that the most of consumers and optometrists in Busan and Ulsan agreed on perception toward a conversion of spectacle frame into medical devices. But, we are considered that consumers' and optometrists' active attention and support are needed, with sequential implementation reflecting the concerns for this.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.6
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• pp.9-16
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• 2000

In order to achieve stiction-free polysilicon surfaces, we have suggested a new class of chemical coating precursors and confirmed their excellent characteristics. The strategy is to adopt dialkyldichlorosilanes (DDS, $R2SiCl_2$) instead of monoalkyltrichlorosilanes (MTS, $RSiCl_3$) such as octadecyltrichlorosilane (OTS) or 1H,1H2H,2H-perfluorodecyltrichlorosilane (FDTS). Dichlorodimethylsilane (DDMS, $(CH_3)2SiCl_2$) in this study is commercially available DDS with two short chains. DDMS in aprotic media spontaneously deposits on the hydrophilic polysilicon surface, which is completely changed to hydrophobic one. When polysilicon surface is exposed to DDMS solution at room temperature, anti-stiction property and hydrophobicity are clearly comparable to FDTS. DDMS is even superior to MTS in reliability and easy handling, which provides high yield. Since interactions among precursor molecules are reduced, conglomeration both in homogeneous solution and on surface can be effectively avoided. Even the cantilevers of 3 mm in length can be protected successfully from the stiction and the final quality of the modified surfaces is much less dependent on temperature. And no difference was found between the processes in ambient environment and in dry box. In addition, DDMS has advantages of remarkably reduced process time and low cost.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.4
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• pp.28-38
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• 2009

In this study, a remote air quality monitoring system for underground spaces was developed by using NDIR-based CO$_2$ sensor. And the remote monitoring system based on wireless sensor networks was installed practically on the subway station platform. More than 6.5 million citizens commutate everyday by the Seoul subway transportation that is the most typical public transportation. They concern about air quality with increasing interest on public health or many workers in subway stations or underground shopping centers. Recently, the Korean Ministry of Environment has operated the air quality monitoring system in some subway stations for testing phase. However, it showed many defects which are large-scale, high-cost and maintenance of precision sensors imported from abroad. Therefore this research includes the reliability test and a theoretical study about the inexpensive commercialized CO$_2$ sensor for reliable measurement of air quality which changes rapidly by the surrounding environments. And then we develop the wireless sensor nodes and the gateway applied for remote air quality monitoring. In addition, web server program was realized to manage air quality in the subway platform. This result will be valuable for a basic research for air quality management in underground spaces for future study.

• Journal of Environmental Impact Assessment
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• v.27 no.4
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• pp.378-393
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• 2018

As atmospheric fine dust problems in Korea become more serious, there are growing needs to find the concentration of fine particles in indoor and outdoor areas and there are increasing demands for sensor-based portable monitoring devices capable of measuring fine dust concentrations instantly. The low-cost portable monitoring devices have been widely manufactured and used without the prescribed certification standards which would cause unnecessary confusion to the concerned public. To evaluate the reliability those devices and to improve their usability, following studies were conducted in this work; 1) The comparisons between sensor-based devices and comparison with more accurate devices were performed. 2) Several experiments were conducted to understand usefulness of the portable monitoring devices. As results, the absolute concentration levels need to be adjusted due to insensitivity of the tiny light scattering sensors in the portable devices, but their linearity and reproducibility seem to be acceptable. By using those monitoring devices, users are expected to have benefits of recognizing the changes of concentration more quickly and could help preventing themselves from the adverse health impacts.

• Science of Emotion and Sensibility
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• v.23 no.1
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• pp.3-16
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• 2020

Recently, as the fashion e-commerce market has expanded, the proportion of online shops that are growing rapidly has increased and with them so too has competition. Most retailers operating online shops need their own competitiveness, and accordingly, the need to develop their logistics service quality components is increasing. This study investigated the quality of the logistics services, which is a factor of the logistics service quality of the internet shop. It influences customer satisfaction and repurchase intention by collecting samples from the customers using online fashion shops. Two hundred customers who shop online were surveyed to extract the data. The sample was subjected to basic statistical analysis using the SPSS 25.0 package, and factor analysis, t-test, ANOVA, and correlation analysis were performed. The results of this study showed that the information quality of proactive return, promptness of the return process, and reliability of the return cost had a positive impact on customer satisfaction, and it had a significant influence on the customer's repurchase intention to the online store. A selection of shops showed high amounts of return reasons, high customer satisfaction, and high repurchase, whereas, in general, many others scored poorly across these criteria. This suggests that a retailer operating online should consider pages for receiving information plus sales content in addition to the quality and constituent factors of its logistics services for returns that influence repurchase and satisfaction.

• Journal of Science and Technology Studies
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• v.18 no.2
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• pp.7-41
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• 2018

The projects of citizen science which is originated from citizen data collecting action driven by governmental institutes and science associations have been implemented with different form of collaboration with scientists. The themes of citizen science has extended from the ecology to astronomy, distributed computing, and particle physics. Citizen science could contribute to the advancement of science through cost-effective science research based on citizen volunteer data collecting. In addition, citizen science enhance the public understanding of science by increasing knowledge of citizen participants. The community-led citizen science projects could raise public awareness of environmental problems and promote the participation in environmental problem-solving. Citizen science projects based on local tacit knowledge can be of benefit to the local environmental policy decision making and implementation of policy. These social values of citizen science make many countries develop promoting policies of citizen science. The korean government also has introduced some citizen science projects. However there are some obstacles, such as low participation of citizen and scientists in projects which the government has to overcome in order to promote citizen science. It is important that scientists could recognize values of citizen science through the successful government driven citizen science projects and the evaluation tool of scientific career could be modified in order to promote scientist's participation. The project management should be well planned to intensify citizen participation. The government should prepare open data policy which could support a data reliability of the community-led monitoring projects. It is also desirable that a citizen science network could be made with the purpose of sharing best practices of citizen science.