• Title/Summary/Keyword: Power System Analysis

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A Study on Improvement of Directional Errors for K-MLRS Launcher (천무 발사대 방향성 오류현상 개선에 관한 연구)

  • Kim, Hyeeun;Kim, Minchang;Yu, Hanjun;Bae, Gongmyeong;Oh, Eunbin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.2
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    • pp.705-713
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    • 2021
  • Because the cage assembly serves as the launch platform, an accurate aim is essential to ensure shooting accuracy for the target. On the other hand, the abnormal rotation of the cage due to the directional errors of the K-MLRS has continuously caused quality problems. The quality problem of weapon systems may have a negative impact on the military's power loss. In this study, improvement plans were derived by examining the defects and analyzing the directional errors of the K-MLRS launcher. In addition, all possible causes of directional errors were derived from the flow diagram for cage directionality. Based on the results, the defense design through the software program was intended to prevent the loss of direction. Through this study, the signal error of the resolver was improved by preventing unspecific signals in the data. Furthermore, the directional judgment method was improved to minimize the impact of data distortion. Lastly, directional storage and verification methods were improved so that data for the cage rotation direction would not be affected by errors. For the design improvement method, the reliability was verified through the system applicability. This study is expected to be a reference for failure analysis and design for similar weapon systems in the future.

A Study on Structural Analysis for Improving Driving Performance of Agricultural Electric Car (농업용 전기운반차의 주행성능 향상을 위한 구조해석에 관한 연구)

  • Jo, Jae-Hyun;Lee, Sang-Sik
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.13 no.6
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    • pp.556-561
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    • 2020
  • The aging and declining agricultural population in the modern society requires improvement of the agricultural environment and is one of the representative problems. And since most of the work systems always require a transport work, the ratio of labor consumed in the transport work is very high. Accordingly, many types of transport vehicles are being developed and sold, and in the early days, most of them are powered transport vehicles using fossil fuels. However, it is paying attention to next-generation eco-friendly energy such as hydrogen, fuel cells, solar power, and bio due to the strengthening of international environmental regulations such as global warming and the Convention on Climate Change and the depletion of fossil fuels. Therefore, in this study, the ultimate goal is to develop an eco-friendly, easy-to-operate, safe agricultural electric vehicle that replaces fossil fuels. It was designed with a focus on controlling a wide range of vehicle speeds and securing stability of electric agricultural vehicles. Considering the performance and design, it is composed of a frame, a driving part, a steering part, and a controller system, and we are going to review and manufacture each part. It is believed that the manufactured electric vehicle for agriculture can be easily and conveniently operated in an agricultural society where young manpower is scarce, and can be helpful to the agricultural society through high efficiency.

An Analysis on Limited Warfare through the Falkland Islands Dispute (포클랜드제도 분쟁을 통한 제한전 분석)

  • Yang, Seong-sil;Lee, Hee-wan;Shin, Jin
    • Maritime Security
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    • v.3 no.1
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    • pp.211-235
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    • 2021
  • As a result of the Falkland Islands War from April 2 to June 14, 1982, Britain overcame severe economic depression and reclaimed the glory of the former British Empire by winning the war. On the other hand, Argentina was greatly affected by the collapse of a military dictatorship and the birth of a democratic government. This study suggests strategies for responding to maritime disputes that may occur in Dokdo Island in the future by applying "DIME on PMESII" to the Falkland Islands dispute. In particular, the study analyzes how DIME (diplomacy, information, military, and economy) capabilities have an effect as a means of the total national power of a country that effectively controls the disputed territory. Based on the results of this study, the response strategies related to the Dokdo maritime dispute are as follows. First, effective control over the disputed territory should be effectively maintained and strengthened like in Britain. This strategy inspires patriotism, supports the government during warfare, secures a just cause for war, and gains international support. Second, 'DIME on PMESII' was effective in modern warfare by focusing our DIME capabilities on the weaknesses of the other country's PMESII system. That is, wars are not won simply by the conflict of armed forces but by a nation's overall national strength, such as diplomatic, information, and economic capabilities. Third, appropriate strategies for neighboring countries are needed to overcome the possibility of limited warfare in the sea through preparations for Dokdo maritime disputes in the future.

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A CFD Study on Aerodynamic Performances by Geometrical Configuration of Guide Vanes in a Denitrification Facility (탈질 설비 내 안내 깃의 기하학적 형상에 따른 공력 성능에 대한 전산 해석적 연구)

  • Chang-Sik, Lee;Min-Kyu, Kim;Byung-Hee, Ahn;Hee-Taeg, Chung
    • Clean Technology
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    • v.28 no.4
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    • pp.316-322
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    • 2022
  • The flow pattern at the inlet of the catalyst layer in a selective catalytic reduction (SCR) system is one of the key parameters influencing the performance of the denitrification process. In the curved diffusing parts between the ammonia injection grids and the catalyst layers, guide vanes are installed to improve flow uniformity. In the present study, a numerical simulation has been performed to investigate the effect of the geometrical configuration of the guide vanes on the aerodynamic characteristics of a denitrification facility. This application has been made to the existing SCR process in a large-scaled coal-fired power plant. The flow domain to be solved covers the whole region of the flow passages from the exit of the ammonia injection gun to the exit of the catalyst layers. ANSYS-Fluent was used to calculate the three-dimensional steady viscous flow fields with the proper turbulence model fitted to the flow characteristics. The root mean square of velocity and the pressure drop inside the flow passages were chosen as the key performance parameters. Four types of guides vanes were proposed to improve the flow quality compared to the current configuration. The numerical results showed that the type 4 configuration was the most effective at improving the aerodynamic performance in terms of flow uniformity and pressure loss.

Steel Frame Clamp Deformation and Performance Check based on Clamping Orientation (철골용 클램프 시공방향에 따른 변형 및 성능확인)

  • Mo, Seung-Un;Lim, Nam-Gi
    • Journal of the Korea Institute of Building Construction
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    • v.22 no.2
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    • pp.161-169
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    • 2022
  • The government [3] specifies steel pipe scaffolding as conventional scaffolding and is promoting the installation of system scaffolding, an integrated work platform, and avoidance of the use of steel pipe scaffolding as much as possible. However, in places where equipment cannot enter, such as power plants and plant sites, places the structure is complex, and places where scaffolding cannot be stacked on the ground, there is no choice but to install steel pipe scaffolding. When installing steel pipe scaffolding on an H-beam structure at a high place, the performance of the steel frame clamp is very important in order to form a work space which workers can work safely. In this study, the displacement magnitude and tensile load of members in each installation direction of the clamp for steel frame were verified through performance tests and structural analysis modeling. As a result, it was confirmed that the performance for each installation direction satisfies the safety certification standard tensile load of 10,000N. Although the performance value is satisfactory, deformation of the attachment pressing bolt was verified and was confirmed to have minimal deformation. Thus, to ensure the load is properly to the attachment body, the clamp for a steel frame must be installed in the direction in which the load is transmitted.

The Effect of Rice Co-Brand Assets, Trust, and Attachment on Loyalty (쌀 공동브랜드의 자산, 신뢰, 애착이 충성도에 미치는 영향)

  • Kim, Shine
    • Journal of Digital Convergence
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    • v.20 no.5
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    • pp.401-410
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    • 2022
  • This study deals with the relationship among trust, attachment and brand loyalty of agricultural products' rice co-brands, which are the staple food of the people. The research method established the hypothesis of the study under the foundation of prior research and developed the survey. The subjects of the study were distributed, retrieved, and analyzed the survey of 163 rice farmers in Buyeo-gun, Chungcheongnam-do. The empirical analysis results show that: First, hypothesis 1 of the brand awareness and image that "rice brand assets will be a positive relationship to trust" were statistically adopted. In particular, statistical t values showed a difference in consumer confidence over recognition>images. Second, hypothesis 2 of the trust of agricultural rice brands will be a positive influence on attachment and loyalty' statistically supported. In this regard, brand trust was higher in loyalty than attachment. Third, the attachment of agricultural products to rice brands will be a positive influence on loyalty,' was statistically supported. The strategic implications of this study are as follows. First, consumers should be given clues of trust(ex, GAP of Natioanl Approval Licesing, Fam Tour) as they distrust the perceived quality of the rice in the market. Second, the effect of the origin of rice is questionable, so the spread of the production power system should prevent the mixing of rice varieties, that is the spread of the production history systems.

A Study of e-RTGC Introduction Effects in the Container Terminal : Based on D Container Terminal Case Study (컨테이너터미널에서 e-RTGC의 도입효과에 관한 연구: D터미널 사례를 중심으로)

  • Choi, Hyung-Rim;Lee, Seung-Hon;Park, Yong-Sung;Kang, Moo-Hong;Kim, Hee-Yoon;Choi, Ki-Nam;Joo, Yi-Don;Ha, Jeong-Su
    • Journal of Korea Society of Industrial Information Systems
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    • v.14 no.5
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    • pp.289-296
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    • 2009
  • All over the world more and more attention is being paid to green management which enables environment-friendly sustainable development. To keep up with these global trends and in response to the government's "low carbon green growth" policy, many efforts are being made in the port and logistics in order to drastically reduce carbon emissions and save operating expenses. To this end, the engine power source of the cranes in the container terminal is being replaced with electricity from fossil fuel. Among those cranes, especially e-RTGC has been proved to be practical and excellent in its performance through many previous studies. However, no empirical study has yet been made on its introduction effects when e-RTGC has been introduced to the container terminal. In the meantime, however, many domestic container terminals have introduced e-RTGC, and so some data have been accumulated for further research. Under these circumstances, this study has tried to make an empirical study through the case study of D container terminal, checking the restriction factors to be considered at the time of eURTGC introduction, and analyzing its introduction effects and problems. We have high expectations that this study will provide key consideration factors and empirical analysis data to the decision makers who plan to introduce an e-RTGC system, and also will be used as a reference to the development direction of e-RTGC.

Kangjeungsan(姜甑山)'s Embracement of Chinese Myth and It's Meaning (강증산(姜甑山)의 중국신화 수용과 그 의미)

  • Jung, Jae-seo
    • Journal of the Daesoon Academy of Sciences
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    • v.25_1
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    • pp.1-22
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    • 2015
  • This paper took Jeonkyeong (典經) of Daesunjinrihoe(大巡眞理會) as the basic text and studied how Kangjeungsan(姜甑山), the Sangje (上帝), had embraced Chinese myth in process of formation of his religious thought focusing on Yan Emperor(炎帝) Shennong(神農) myth and Shanrangang(禪讓) myth (namely Danchu myth). First when we examine the myth surrounding Kangjeungsan's birth, it deeply emraced a feeling-birth myth(感生神話), we could realize that this is a universe motif through myth of hero birth in East Asia. Further judging from the analysis of geographic space of Kangjeungsan's activity, it included a variety of mythical and Daoist related place names. I think this is because of the fact that birth place of Kangjeungsan and the surrounding area is the locality of Xian(仙) tradition where major characters of Danhak sect(丹學派) have been turned out, and that Korean way of Xian suppressed by the regulatory system has been widely rooted in the public. Especially it's interesting that Jeungsan, the pen name of Kangjeungsan, ambiguously connotes Siru mountain(甑山), a place of his training, and the spiritual realm of the 『Zhouyicantongqi(周易參同契)』. Then I examined the God of fire Shennong myth which has been actively admitted and embraced by Kangjeungsan. Kangjeungsan put the root of his pedigree on Shennong and there is a close affinity between Shennong and Dongyi(東夷) such as Buyeo(夫餘), Goguryeo(高句麗), etc. These Dongyi spirits are losers against the Chinese major myth and beings of ressentiment. At the same time the predecessor of Jiutianyingyuanleishengpuhuatianzun(九天應元雷聲普化天尊) who shares mythical characteristics with the God of fire Shennong was a formerly Taishi(太師) Wenzhong(聞仲) of Yin(殷) dynasty. He was defeated and died by Zhou(周) dynasty, and was deified. The fact that Kangjeungsan regarded himself as a descendent of Shennong and possessed divinity of Jiutianyingyuanleishengpuhuatianzun connotes that he represents all beings of ressentiment such as family of Yin and Dongyi. However, Kangjeungsan set a religious milestone by turning revenge for such ressentiment at tribe level into religious sublimation. At the end Shanrang myth which has been critically embraced by Kangjeungsan was reviewed. According to the existing Shanrang myth, Danchu(丹朱) was unworthy and not succeeded in the succession to the throne. Then good natured Emperor Shun(舜) succeeded to the throne from Emperor Yao(堯). However, the reality of Shanrang myth was a violent change of sovereign power and Danchu was a victim in the process of such violent change. Kangjeungsan shrewdly grasped the reality of ancient China and cast light on presence of Danchu. And he emphasized the need of religious sublimation of revenge, Haewon(解冤). His such awareness of culture had a close relation with revisionist standpoint of independent Danhak sect expressing a skeptical glance at systematic, commensurate and authentic historical view of Chinese civilization. And further Kangjeungsan cosmologically and causationally reinterpreted revenge of Danchu. He established a universal salvation theology which has a corresponsive connotation in regard to embracement of Shennong myth. In conclusion, embracement of Chinese myth by Kangjeungsan was a creative work of reinterpretation resulting in an inherent religious connotation through a process of appropriation, that is independent and selective introjection.

Literature Review on Health Effect Surveys of Residents in Environmentally Contaminated Areas in South Korea from 1997 to 2021 (한국 환경오염 취약지역 주민 건강영향조사 문헌고찰(1997~2021))

  • Kyung-Hwa Choi;Sujung Kim;Hyun A Jang;Dahee Han;Ho-Jang Kwon;Yong Min Cho
    • Journal of Environmental Health Sciences
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    • v.49 no.3
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    • pp.134-148
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    • 2023
  • Background: The conducting of health effect surveys (HESs) in environmentally contaminated vulnerable areas (ECVAs) by the central and local governments has been increasing apace with the increase in demand for HESs since the Environmental Health Act was enacted in South Korea in 2008. Objectives: This study aimed to review the HESs of residents in ECVAs conducted in South Korea. Methods: An analysis was performed on 125 reports obtained from the Environment Digital Library, PRISM, and local government websites after selecting from 803 projects obtained as ECVAs from the Korea ON-Line E-Procurement System (1997~2021), National Institute Environment Research (2000~2021), and Korea Environmental Industry and Technology Institute (2009~2021). The reports were classified by background (residents' demand, HES, and more), research design (cross-sectional study, cohort, ecological study, and panel), pollution source (abandoned metal mine (AMM), industrial complex (IC), and more), and assessment method of exposure and health effects. The survey area was converted into administrative district codes for geographical mapping. Results: There were 37, 34, 18, and 10 cases associated with AMM, IC, waste incinerators, and coal-fired power plants, respectively. Most of the studies conducted were cross-sectional studies and ecological studies. The proportion of epidemiological investigations by residents' demand showed an increase from 0.0% to 8.9% for the central government while decreasing from 16.7% to 14.3% for local governments after 2008 compared to before 2008. HESs increased at both the central and local government levels since 2014. For the evaluation method, 365 environmental hazards, 319 health outcomes, and 302 biological markers were investigated, with the most commonly investigated items being metals, cancer, and blood metals. Conclusions: HESs of residents in ECVAs in South Korea have been continuously developed both quantitatively and qualitatively. Future improvements are expected, and systematic review and classification of the HESs is warranted.

A Study on Factor Influencing the Nutrition Quotient for Elderly(NQ-E) of Elderly Living Alone (노인 1인 가구의 노인영양지수(NQ-E)에 영향을 미치는 요인에 관한 연구)

  • Kim, Kawon;Hur, Junsoo
    • 한국노년학
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    • v.39 no.4
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    • pp.741-762
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    • 2019
  • The purpose of this study is to identify the Nutrition Quotient for Elderly(NQ-E) of the elderly living in the community and to investigate the characteristics of living conditions affecting the nutritional status of the elderly. The subjects of the survey were 1,970 elderly single elderly households aged 65 and over in the nationwide through convenience sampling method. A survey cooperative system was established with Comprehensive Support Center for Elderly Living Alone, and the 25 social welfare institutions. 385 Life Managers for Elderly Living Alone participated as a survey agent. As a result, NQ-E was 51.14 points, which is the lowest level in the NQ-E, and the explanatory power was 20.1% in multiple regression analysis. Significant variables were age, sex, subjective health status, low number of medication, non-smoker, non-alcoholic, satisfactory economic status, academic status, and the interaction with family and neighbors. Based on this result, this study explains that comprehensive measures of nutritional management for the elderly living alone needs to be sought.