• Title/Summary/Keyword: frequency-response

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Fishermen's Perceptions and Considerations regarding the Coexistence of Fishing Activities within Offshore Wind Farms

  • Yu-Jeong Mun;Cho-Young Jung
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.30 no.3
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    • pp.283-290
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    • 2024
  • In this study, a survey on the coexistence of offshore wind farm and fishing activities in Gochang, Gunsan, and Buan's fishermen in the southwest sea of shore wind farm was carried out witn an aim of examining the factors that should be considered when coexisting. A questionnaire was composed after referring to domestic and foreign literature data on examples of coexistence. The questionnaire was issued through direct visits. Frequency analysis and cross-analysis were used for survey response results, and IBM SPSS Statistics ver. 26 was used for statistical processing. As a result of analyzing a total of 84 questionnaires, the perception of the coexistence of offshore wind and fishing activities was the same by 50.0% positive and negative, respectively. As a result of cross-analysis by region, significant differences were found (p <0.039). Gochang fishermen showed a high negative perception of the coexistence of offshore wind and fishing activities at 62.1%, with the main reason being that fishing resources are expected to decrease due to the influence of noise, vibration, and current generated from offshore wind farm facilities. In Gunsan, negative perception of coexistence was high at 57.7%. This was mainly attributed to the impossibility to operate in the offshore wind farm due to the nature of the fishery. On the contrary, in the case of Buan, 69.0% of the positive perception of coexistence was high 'because fishermen were dissatisfied with the current coexistence plan (policy)'. According to previous studies, 91.8% of domestic fishing methods show the possibility of fishing activities in offshore wind under caution, so it is concluded that research should be conducted to coexist with offshore wind and fishing activities as in foreign countries for smooth installation of offshore wind and continuous fishing activities.

Effect of (Al, Nb) Co-Doping on the Complex Dielectric Properties and Electric Modulus of BaTiO3-Based Ceramics

  • Ziheng Huang;Ruifeng Niu; Depeng Wang;Weitian Wang
    • Korean Journal of Materials Research
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    • v.34 no.7
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    • pp.321-329
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    • 2024
  • In this work, a series of BaTiO3-based ceramic materials, Ba(Al0.5Nb0.5)xTi1-xO3 (x = 0, 0.04, 0.06, 0.08), were synthesized using a standard solid-state reaction technique. X-ray diffraction profiles indicated that the Al+Nb co-doping into BaTiO3 does not change the crystal structure significantly with a doping concentration up to 8 %. The doping ions exist in Al3+ and Nb5+ chemical states, as revealed by X-ray photoelectron spectroscopy. The frequency-dependent complex dielectric properties and electric modulus were studied in the temperature range of 100~380 K. A colossal dielectric permittivity (>1.5 × 104) and low dielectric loss (<0.01) were demonstrated at the optimal dopant concentration x = 0.04. The observed dielectric behavior of Ba(Al0.5Nb0.5)xTi1-xO3 ceramics can be attributed to the Universal Dielectric Response. The complex electric modulus spectra indicated the grains exhibited a significant decrease in capacitance and permittivity with increasing co-doping concentration. Our results provide insight into the roles of donor and acceptor co-doping on the properties of BaTiO3-based ceramics, which is important for dielectric and energy storage applications.

A Study on the Perceptions of Pre-service Early Childhood Teachers on Climate Change (예비유아교사의 기후변화에 대한 인식 연구)

  • Se-Ru Kim
    • Journal of the Health Care and Life Science
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    • v.10 no.2
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    • pp.379-386
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    • 2022
  • This study was conducted with 150 pre-service early childhood teachers at G University in G Metropolitan City to find out the perceptions of pre-service early childhood teachers on climate change. The questionnaires were collected and frequency, percentage, and multiple response analysis were conducted. As a result of the study, first, all pre-service early childhood teachers perception of climate change was recognized, and a sufficient understanding of the concept of greenhouse effect, concept of climate change, and types of greenhouse gases was required, and scientific knowledge was insufficient. Second, about the relationship between climate change and humans, the causes of global warming and the signals of climate change were properly recognized. The awareness of the effects of global warming was high, but the comprehensive understanding was insufficient. Third, the convention on climate change knows to some extent how to respond to climate change, and the international community recognizes the subject of climate change prevention, and climate mitigation efforts are limited to individuals. It was found that most of the practical contents for reducing carbon emissions in daily life are being practiced well. These results are intended to provide basic data for the development of educational programs for pre-service early childhood teachers on climate change.

Identification of a key signaling network regulating perennating bud dormancy in Panax ginseng

  • Jeoungeui Hong;Soeun Han;Kyoung Rok Geem;Wonsil Bae;Jiyong Kim;Moo-Geun Jee;Jung-Woo Lee;Jang-Uk Kim;Gisuk Lee;Youngsung Joo;Donghwan Shim;Hojin Ryu
    • Journal of Ginseng Research
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    • v.48 no.5
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    • pp.511-519
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    • 2024
  • Background: The cycle of seasonal dormancy of perennating buds is an essential adaptation of perennial plants to unfavorable winter conditions. Plant hormones are key regulators of this critical biological process, which is intricately connected with diverse internal and external factors. Recently, global warming has increased the frequency of aberrant temperature events that negatively affect the dormancy cycle of perennials. Although many studies have been conducted on the perennating organs of Panax ginseng, the molecular aspects of bud dormancy in this species remain largely unknown. Methods: In this study, the molecular physiological responses of three P. ginseng cultivars with different dormancy break phenotypes in the spring were dissected using comparative genome-wide RNA-seq and network analyses. These analyses identified a key role for abscisic acid (ABA) activity in the regulation of bud dormancy. Gene set enrichment analysis revealed that a transcriptional network comprising stress-related hormone responses made a major contribution to the maintenance of dormancy. Results: Increased expression levels of cold response and photosynthesis-related genes were associated with the transition from dormancy to active growth in perennating buds. Finally, the expression patterns of genes encoding ABA transporters, receptors (PYRs/PYLs), PROTEIN PHOSPHATASE 2Cs (PP2Cs), and DELLAs were highly correlated with different dormancy states in three P. ginseng cultivars. Conclusion: This study provides evidence that ABA and stress signaling outputs are intricately connected with a key signaling network to regulate bud dormancy under seasonal conditions in the perennial plant P. ginseng.

Intelligent optimal grey evolutionary algorithm for structural control and analysis

  • Z.Y. Chen;Yahui Meng;Ruei-Yuan Wang;Timothy Chen
    • Smart Structures and Systems
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    • v.33 no.5
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    • pp.365-374
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    • 2024
  • This paper adopts a new approach in which nonlinear vibrations can be controlled using fuzzy controllers by optimal grey evolutionary algorithm. If the fuzzy controller cannot stabilize the systems, then the high frequency is injected into the system to assist the controller, and the system is asymptotically stabilized by adjusting the parameters. This paper uses the GM (grey model) and the neural network prediction model. The structure of the neural network is improved from a single factor, and multiple data inputs are extended to various factors and numerous data inputs. The improved model expands the applicable range of uncontrolled elements and improves the accuracy of controlled prediction, using the model that has been trained and stabilized by multiple learning. The simulation results show that the improved gray neural network model has higher prediction accuracy and reliability than the traditional GM model, improving controlled management and pre-control ability. In the combined prediction, the time series parameters and the predicted values obtained from the GM (1,1) (Grey Model of first order and one variable) are simultaneously used as the input terms of the neural network, considering the influence of the non-equal spacing of the data, which makes the results of the combined gray neural network model more rationalized. By adjusting the model structure and system parameters to simulate and analyze the controlled elements, the corresponding risk change trend graphs and prediction numerical calculation results are obtained, which also realize the effective prediction of controlled elements. According to the controlled warning principle and objective, the fuzzy evaluation method establishes the corresponding early warning response method. The goals of this paper are towards access to adequate, safe and affordable housing and basic services, promotion of inclusive and sustainable urbanization and participation, implementation of sustainable and disaster-resilient buildings, sustainable human settlement planning and manage.

Design Characteristics of Augmented Reality Digital Fashion (증강 현실 디지털 패션의 디자인 특성)

  • Eunjeong Kim;Seunghee Suh
    • Journal of Fashion Business
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    • v.28 no.4
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    • pp.1-20
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    • 2024
  • The aim of this study was to analyze contemporary sociocultural phenomena and values through characteristics of augmented reality (AR) digital fashion design. The research method included a literature review on the metaverse and augmented reality, combined with a case study using both quantitative analysis through big data text mining and qualitative analysis through constant comparison. Data analysis was conducted using Python-based open-source tools: First, 6,725 data entries were collected from AR digital fashion platforms and brands identified in articles from Vogue and Vogue Business containing keywords of 'augmented reality' and 'digital fashion. Second, text preprocessing involved stop word removal, tokenization, and POS-tagging of nouns and adjectives using the NLTK library. Third, top 50 keywords were extracted through term frequency (TF) and TF-IDF analysis, with results visualized using a word cloud. Fourth, characteristics of products' external design and internal concepts that contained top keywords were classified, with their value examined through repeated comparison. Results indicate that AR digital fashion design has the following characteristics. First, it embodies surreal fantasy through designs that mimic natural biological patterns using 3D scanning and modeling technology. Second, it presents a trans-boundary aspect by utilizing the fluidity of body and space to challenge vertical and discriminatory social structures. Third, it imagines a new future transcending traditional sociocultural concepts by expanding perceptions of space and time based on advanced technological aesthetics. Fourth, it contributes to sustainability by exploring alternatives for the fashion industry in response to climate change and ecological concerns.

FR-4 Substrate-Based Metamaterial Lens to Improve Signal Strengths of the Antenna for RF Sensing and Cost Reduction, and Observation of Its Frequency Response (밀리미터파 무선센싱의 신호 강도 향상과 센서 개발비용 절감을 위한 FR-4 기판 메타재질 렌즈의 설계 및 주파수 응답특성의 관찰)

  • Woogon Kim;Yejune Seo;Sungtek Kahng
    • Journal of Advanced Navigation Technology
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    • v.28 no.5
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    • pp.706-712
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    • 2024
  • For wirelessly connecting the RF sensing of the radar with a long distant object, the system must have antennas of a high gain. Conventionally, they adopt arrays and curved lenses, but have problems of conductor and dielectric loss in the feed and ending up with a large volume. This paper proposes an FR-4-substrate flat metasurface lens to intensify the RF signal, which undergoes design, fabrication and test. To verify the design method, the antenna sized 64×64mm2 is prototyped by inexpensive FR-4 PCB etching process and its S11 and radiated wave are measured. Gain increase of around 10 dB and high directivity are observed at the K-band.

The Survey of Dentists: Updated Knowledge about Basic Life support and Experiences of Dental Emergency in Korea

  • Cho, Kyoung-Ah;Kim, Hyuk;Lee, Brian Seonghwa;Kwon, Woon-Yong;Kim, Mi-Seon;Seo, Kwang-Suk;Kim, Hyun-Jeong
    • Journal of The Korean Dental Society of Anesthesiology
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    • v.14 no.1
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    • pp.17-27
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    • 2014
  • Background: Various medical emergency situations can occur during dental practices. Cardiac arrest is known to comprise approximately 1% of emergency situation. Thus, it is necessary for dentists to be able to perform cardiopulmonary resuscitation (CPR) to increase the chance of saving patient's life in emergency situation. In this paper, we conducted a survey study to evaluate to what extent dentists actually understood CPR practice and if they had experience in handling emergency situations in practice. Method: The survey was done for members of the Korean Dental Society of Anesthesiology (KDSA), who had great interest in CPR and for whom survey-by-mail was convenient. We had selected 472 members of the KDSA with a dental license and whose office address and contact information were appropriate, and sent them a survey questionnaire by mail asking about the degree of their CPR understanding and if they had experience of handling emergency questions before. Statistical analyses -frequency analysis, chi-square test, ANOVA, and so on- were performed by use of IBM SPSS Statistics 19 for each question. Result: Among 472 people, 181 responded (38.4% response rate). Among the respondents were 134 male and 47 female dentists. Their average age was $40.4{\pm}8.4$. In terms of practice type, there were 123 private practitioners (68.0%), 20 professors (11.0%), 16 dentists-in-service (8.8%), 13 residents (specialist training) (7.2%) and 9 military doctors (5%). There were 125 dentists (69.1%) who were specialists or receiving training to be specialist, most of whom were oral surgeon (57, 31.5%) and pediatric dentists (56, 30.9%). There were 153 people (85.0%) who received CPR training before, and 65 of them (35.9%) were receiving regular training. When asked about the ratio of chest pressure vs mouth-to-mouth respiration when conducting CPR, 107 people (59.1%) answered 30:2. However, only 27.1% of them answered correctly for a question regarding CPR stages, C(Circulation)- A(Airway)- B(Breathing)- D(Defibrillation), which was defined in revised 2010 CPR practice guideline. Dentists who had experience of handling emergency situations in their practice were 119 (65.6%). The kinds of emergency situations they experienced were syncope (68, 37.6%), allergic reactions to local anesthetic (44, 24.3%), hyperventilation (43, 23.8%), seizure (25, 13.8%), hypoglycemia (15, 8.3%), breathing difficulty (14, 7.8%), cardiac arrest (11, 6.1%), airway obstruction (6, 3.3%), intake of foreign material and angina pectoris (4, 2.2%), in order of frequency. Most respondents answered that they handled the situation appropriately under the given emergency situation. In terms of emergency equipment they had blood pressure device (70.2%), pulse oximetry (69.6%), Bag-Valve-Mask (56.9%), emergency medicine (41.4%), intubation kit (29.8%), automated external defibrillator (23.2%), suction kit (19.3%) and 12 people (6.6%) did not have any equipment. In terms of confidence in handling emergency situation, with 1-10 point scale, their response was $4.86{\pm}2.41$ points. The average point of those who received regular training was $5.92{\pm}2.20$, while those who did not was $4.29{\pm}2.29$ points (P<0.001) Conclusion: The result showed they had good knowledge of CPR but the information they had was not up-to-date. Also, they were frequently exposed to the risk of emergency situation during their dental practice but the level of confidence in handling the emergency situation was intermediate. Therefore, regular training of CPR to prepare them for handling emergency situation is deemed necessary.

Changes and Improvements of the Standardized Eddy Covariance Data Processing in KoFlux (표준화된 KoFlux 에디 공분산 자료 처리 방법의 변화와 개선)

  • Kang, Minseok;Kim, Joon;Lee, Seung-Hoon;Kim, Jongho;Chun, Jung-Hwa;Cho, Sungsik
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.20 no.1
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    • pp.5-17
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    • 2018
  • The standardized eddy covariance flux data processing in KoFlux has been updated, and its database has been amended accordingly. KoFlux data users have not been informed properly regarding these changes and the likely impacts on their analyses. In this paper, we have documented how the current structure of data processing in KoFlux has been established through the changes and improvements to ensure transparency, reliability and usability of the KoFlux database. Due to increasing diversity and complexity of flux site instrumentation and organization, we have re-implemented the previously ignored or simplified procedures in data processing (e.g., frequency response correction, stationarity test), and added new methods for $CH_4$ flux gap-filling and $CO_2$ flux correction and partitioning. To evaluate the effects of the changes, we processed the data measured at a flat and homogeneous paddy field (i.e., HPK) and a deciduous forest in complex and heterogeneous topography (i.e., GDK), and quantified the differences. Based on the results from our overall assessment, it is confirmed that (1) the frequency response correction (HPK: 11~18% of biases for annually integrated values, GDK: 6~10%) and the stationarity test (HPK: 4~19% of biases for annually integrated values, GDK: 9~23%) are important for quality control and (2) the minimization of the missing data and the choice of the appropriate driver (rather than the choice of the gap-filling method) are important to reduce the uncertainty in gap-filled fluxes. These results suggest the future directions for the data processing technology development to ensure the continuity of the long-term KoFlux database.

A Survey on the Effect of Consumer's Social-Economic Status on Beef Purchase Attitude (소비자의 사회 경제적 위치가 쇠고기 구매 태도에 미치는 영향)

  • Lee, Seong-Kap;Yang, Seok-Jin;Kim, Dong-Hoon;Cho, Bong-Jae;Jang, Jung-Young;Lee, Hyo-Ku;Yoon, Bo-Ra;Lee, Young-Jun;Lee, Ok-Hwan
    • The Korean Journal of Food And Nutrition
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    • v.25 no.1
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    • pp.132-141
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    • 2012
  • This current survey was conducted to examine consumer attitudes toward factors determining beef purchasing and improving distribution systems. The frequency of beef purchasing was shown to reflect social and economic status, where inhabitants in large cities, such as Seoul, with higher salaries showed a higher frequency. In addition, consumers that were in their forties bought beef more frequently than consumers that were in their twenties. Consumers in Seoul and the megalopolis with a monthly income of higher than 200 million won preferred to purchase meat from department stores and discount markets. In contrast, people in small cities with lower incomes tended to buy meat from butcher shops and brand shops. In a question regarding unsatisfaction factors of retail beef, individuals that were in their thirties with a high income had concerns associated with packaging problems. For people under thirty with low income, the consistency of quality and price were the prime concerns. In regards to the beef grading system, consumer response varied between inhabitants, monthly income and age group, where consumers from small cities that were in their twenties and forties with a low income had a negative viewpoint. For the differential beef distribution system, housewives between the ages of 30 and 40 from a small city with an income higher than 200 million won had a positive response; however, a large number of consumers were not familiar with this system. The most demanding beef cuts were in the following order: loin, flank and rib. In addition, the most important factors determining purchasing beef were as follows: price, breed and portion.