• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.35-40
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• 2022

This paper proposes an antenna that is located outside the PCB substrate of an electronic product to enable wireless communication in the ISM band. The PCB designed the T-shaped OPEN-STUB power supply line to be miniaturized so that it does not interfere with parts or interfere with design. The characteristics of the antenna were confirmed in the 2.4GHz and 5.8GHz bands using a T-shaped stub feeder and a spiral structure. The size of the antenna is 5mm in width × 6.5mm in length, and the thickness of the PCB is 1.2T. As a result of measurement of the manufactured antenna, it was possible to obtain a return loss of -10dB or more at 2.4GHz and 5.8GHz. In the E-plane, the gain was -4.45 dBi, and in the H-plane, the gain was -1.05 dBi. Therefore, the proposed small antenna for wireless communication showed excellent performance.

• Design & Manufacturing
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• v.16 no.4
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• pp.67-74
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• 2022

Injection molding is a cyclic process comprising of cooling phase as the largest part of this cycle. Providing efficient cooling in lesser cycle times is of significant importance in the molding industry. Recently, lots of researches have been done for rapid cooling of a hot-spot area using CO2 in injection molding. The CO2 flows under high pressure through small, flexible capillary tubes to the point of use, where it expands to create a snow and gas mixture at a temperature of -79℃. The gaseous CO2 removes heat from the mold and releases it into the atmosphere. In this paper, a CO2 cooling module was applied to an injection mold in order to cool a large area cavity uniformly and quickly, and the cooling performance of the injection mold was investigated. The product was a high-curvature molded part with a molding area of 300x100mm. Heat cartridges were installed in a stationary mold, and CO2 cooling module was inserted inside a movable mold. Through structural analysis, it was confirmed that the maximum deformation of mold with CO2 cooling module was 0.09mm. A CO2 feed system with a heat exchanger was used for cooling experiments. The CO2 was injected into the holes on both sides of the supply pipe of the cooling module and discharged through hexagon blocks to cool the mold. It took 5.8 seconds to cool the mold from an average temperature of 140℃ to 70℃. Through the experiment using CO2 cooling module, it was found that a cooling rate of up to 12.98℃/s and an average of 10.18℃/s could be achieved.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.1-11
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• 2010

K company produces semiconductor package products under the make-to-order policy to supply for domestic and foreign semiconductor manufacturing companies. Its production process is a machine-paced assembly line type, which consists of die sawing, assembly, and test. This paper suggests three plans to increase process throughput based on the process analysis of K company and evaluates them via a simulation model using a real data collected. The three plans are line balancing by adding machines to the bottleneck process, product group scheduling, and reallocation of the operators in non-bottleneck processes. The evaluation result shows the highest daily throughput increase of 17.3% with an effect of 2.8% reduction of due date violation when the three plans are applied together. Payback period for the mixed application of the three plans is obtained as 1.37 years.

• Korean Journal of Community Nutrition
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• v.28 no.4
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• pp.329-339
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• 2023

Objectives: This study aims to explore consumer awareness and usage patterns of local food in Jecheon city during the COVID-19 pandemic, contributing to the establishment of the Jecheon City Food Plan. Methods: Surveys were conducted from July 24 to August 24, 2021, using a combination of web-link and self-administered methods for adults living in Jecheon city (n = 250). Descriptive analysis, t-test, importance and satisfaction analysis (ISA) of local food choice attributes were performed using SPSS Statistics. Results: Participants prioritized freshness when purchasing agricultural products. The freshness of Jecheon local food was the selection attribute with the highest consumer satisfaction and could provide purchase motivation. Approximately 73.6% of respondents understood the concept of local food, and 70% were familiar with Jecheon's local food. Notably, 94.8% expressed an intention to purchase but held negative views on selling local food in other areas. The need to increase the supply of local food to vulnerable populations and public school catering was highly recognized. The ISA identified 'affordable price', 'delivery service', and 'product information' as areas requiring improvement. On the other hand, 'freshness of products', 'quality for the price', and 'support for local farmers and economy' were identified as attributes to be maintained and strengthened. Conclusions: Consumers in Jecheon city recognized local foods as more than just 'consumer goods'. Our findings suggest the need for further research on local food revitalization and more comprehensive local food planning to enhance consumer satisfaction.

• Journal of Microbiology and Biotechnology
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• v.33 no.2
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• pp.151-166
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• 2023

Yeast extract is a product prepared mainly from waste brewer's yeast, which is rich in nucleotides, proteins, amino acids, sugars and a variety of trace elements, and has the advantages of low production cost and abundant supply of raw material. Consequently, yeast extracts are widely used in various fields as animal feed additives, food flavoring agents and additives, cosmetic supplements, and microbial fermentation media; however, their full potential has not yet been realized. To improve understanding of current research knowledge, this review summarizes the ingredients, production technology, and applications of yeast extracts, and discusses the relationship between their properties and applications. Developmental trends and future prospects of yeast extract are also previewed, with the aim of providing a theoretical basis for the development and expansion of future applications.

• Korean Journal of Construction Engineering and Management
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• v.24 no.2
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• pp.37-49
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• 2023

In this study, we proposed resource allocation methodologies to improve the productivity of steel bridge manufacturing plants based on the constraint theory which is very popular in the area of manufacturing industries. To this end, after defining the painting process as a bottleneck, three resource allocation methodologies were developed: Operation Specific Resource Allocation (OSRA), Product Specific Resource Allocation (PSRA), and General Resource Allocation (GRA). As a result of experiments for performance evaluation using a simulation model of the steel bridge supply chain, GRA showed the best performance in terms of the Number of Work-In-Process (NWIP) and Waiting Time (WT), in particular, as workload itself and its variability were increased, the performance gap with the specific resource allocation became further deepened. On average, GRA reduced NWIP by 36.2% and WT by 34.6% compared to OSRA, and reduced NWIP by 71.0% and WT by 70.4% compared to PSRA. The reduction of NWIP and WT means alleviating the bottleneck of the painting process, which eventually means that the productivity of the steel bridge manufacturing plant has improved.

• Journal of Korean Society for Atmospheric Environment
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• v.5 no.1
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• pp.33-42
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• 1989

Nowadays, nuclear power production plays a principal role in the electrical energy supply. However, a nuclear power plants emit small amounts of radio-activity due to mostly fission product gases to the local environment during their normal operation. They may release considerably more radioactivity when accidents occur. It is quite necessary to be able to calculate the radiation doses to the general public from such radioactivity releases in order to evaluate the environmental impact of the normally operating nuclear power plant, to assure that this is within acceptable radiation standards, and to ascertain the radiological consequences of nuclear reactor accidents. Such computations also play an important role in determining the acceptability of a proposed nuclear reactor site. Before radiation dose calculations can be carried out, therefore, it is necessary to determine how the concentration of the radioactive effluents is distributed in the environment following their emissions into the atmosphere. This matter is considered and radiation dose calculations are mentioned in conclusions.

• The Journal of the Convergence on Culture Technology
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• v.9 no.3
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• pp.601-606
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• 2023

The edible sweetener aspartame is formed from the synthesis of asparagine, one of the amino acids, and phenylalanine. It is a protein ingredient that produces sweetness 200 times higher than sucrose, and is used as a diet product because it is a substance that can replace sugar. Although the effects on animals and humans have been well studied, no studies have been conducted on plant metabolism. In this study, the effect of aspartame metabolism was tested using germinated onion, bean sprouts, and Kalanchoe. The three types of plants with germinated roots showed rapid growth in the early stage of treatment with 1mM aspartame, and showed a nutrient supply effect due to the effect of amino acids, which are constituents. However, when treated for 4 weeks, symptoms similar to lateral roots appear in the form of lignification in onions, the effect of quickly withering is seen in bean sprouts, and senescence of roots appears in 12-week-old Kalanchoe. All of them show accelerated aging after the growth phase. This shows that, among the two amino acids, asparagine is related to auxin generation that induces rapid growth, and it is thought to be the result of lignification due to the effect of phenylalanine.

• International Area Studies Review
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• v.15 no.1
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• pp.135-169
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• 2011

This study is for analyzing the management performances of Korean tourism firms, operating as preparing strategically against FTA which is one of the most importantly external environment in international management since in the middle of 1990s. The main purpose is to test empirically some relations between the management performances and the levels of ownership-specifics advantages of Korean tourism ones. To be exact, the dependent variables of management performances are classified with sales, profits and management satisfaction, while the independent ones of the competitive advantages are sorted with the 5 following factors like marketing, product development, service supply, finance and organization culture. The survey of Korean tourism enterprises engaging in management activities in Korea is implemented by collecting questionnaires. And for testing the hypothesis, the analyzing tools are being used for correlation, reliability, validity, multi regression and the path analysis of structural equation modeling. As a result, Marketing is certified as only common factor to influence three dependent variables of sales, profit and management satisfaction positively.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.46 no.3
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• pp.23-31
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• 2023

In this study, a smart bench was developed and researched smart benches that can contribute to user convenience and satisfaction by installing them in parks, bus stops, and tourist attractions in line with the rapidly changing construction of smart cities. The smart bench is automatically operated by the control system according to the external temperature and provides additional functions such as charging, lighting, and advertising to improve general bench functions as well as heating in winter and cooling in summer, making it suitable for smart urbanization. The developed smart bench is designed to be strong enough to withstand loads of about 2,500 N. It minimizes the visible parts such as assembled bolts and 220V power supply wires, It can also give aesthetic effects. The development was carried out with the aim of waterproofing and dustproofing of IP44 grade in accordance with the climate of Republic of Korea, which has four seasons, and it is advantageous for long-term use because the paint was selected for the weather ability (discoloration) grade 3 or higher. If smart bench is commercialized, it is believed that various options can be provided to the smart bench market, where buyers had few product options, as the parts were developed in an assembled type so that all functions can be responded in an optional form according to the installation environment and the buyer's budget.