• 제목/요약/키워드: fundamental solution.

검색결과 739건 처리시간 0.031초

Peracetic Acid Treatment as an Effective Method to Protect Wood Discoloration by UV Light

  • PARK, Kyoung-Chan;KIM, Byeongho;PARK, Hanna;PARK, Se-Yeong
    • Journal of the Korean Wood Science and Technology
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    • 제50권4호
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    • pp.283-298
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    • 2022
  • Wood has always been used for various day-to-day applications such as interior or exterior construction materials, and household products. However, it can undergo photodegradation and discoloration by environmental factors including ultraviolet (UV) light, and thus has shortened its service life. Bleaching or delignification of wood surfaces is a suitable solution to stabilize wood against weathering by UV because these techniques can alter or remove the chromophores in lignin, which is a main factor of wood discoloration. To improve the color stability of wood surface according to the lifespan, surface delignification was conducted using peracetic acid (PAA) and hydrogen peroxide (HP) on the woods of Larix kaempferi and Quercus mongolica. After the PAA treatment, L* increased considerably from 60-70 to 90-95. Furthermore, wood surface color did not change significantly after UV exposure. The color differences (𝜟E*) between before and after PPA treatment of wood showed the 4.8-12.2 of L. kaempferi, and 1.7-3.7 of Q. mongolica, respectively. The lignin-related peaks in Fourier transform infrared spectroscopy (FT-IR) spectra disappeared with increased duration of PAA treatment. These results confirmed that the lignin component was partially or completely removed after the PAA treatment; the color differences (𝜟E*) clearly showed that there was a reduction in redness (a*) and yellowness (b*), and an increase in lightness (L*) owing to the removal of lignin. Based on these results, this study demonstrated that the partial removal of lignin from wood surfaces is a fundamental method for resolving photo-degradation.

Pest Prediction in Rice using IoT and Feed Forward Neural Network

  • Latif, Muhammad Salman;Kazmi, Rafaqat;Khan, Nadia;Majeed, Rizwan;Ikram, Sunnia;Ali-Shahid, Malik Muhammad
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제16권1호
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    • pp.133-152
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    • 2022
  • Rice is a fundamental staple food commodity all around the world. Globally, it is grown over 167 million hectares and occupies almost 1/5th of total cultivated land under cereals. With a total production of 782 million metric tons in 2018. In Pakistan, it is the 2nd largest crop being produced and 3rd largest food commodity after sugarcane and rice. The stem borers a type of pest in rice and other crops, Scirpophaga incertulas or the yellow stem borer is very serious pest and a major cause of yield loss, more than 90% damage is recorded in Pakistan on rice crop. Yellow stem borer population of rice could be stimulated with various environmental factors which includes relative humidity, light, and environmental temperature. Focus of this study is to find the environmental factors changes i.e., temperature, relative humidity and rainfall that can lead to cause outbreaks of yellow stem borers. this study helps to find out the hot spots of insect pest in rice field with a control of farmer's palm. Proposed system uses temperature, relative humidity, and rain sensor along with artificial neural network to predict yellow stem borer attack and generate warning to take necessary precautions. result shows 85.6% accuracy and accuracy gradually increased after repeating several training rounds. This system can be good IoT based solution for pest attack prediction which is cost effective and accurate.

디지털 네이티브 세대를 위한 유튜브 리터러시 체크리스트 개발 연구 (Development of Youtube Literacy Checklist for Digital Natives)

  • 김형진;정효정;권보람
    • 한국콘텐츠학회논문지
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    • 제22권3호
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    • pp.273-284
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    • 2022
  • 유튜브 사용량은 계속해서 증가하고 있으며, 유튜브를 가장 많은 시간 사용하는 연령대는 10대로 조사되고 있다. 어린이·청소년이 유해한 콘텐츠에 노출되는 것을 막는 것은 현실적으로 불가능하므로, 유튜브 콘텐츠를 건강하게 선택하고 활용하는 역량을 키워내는 것이 근본적인 해결책이 될 수 있다. 이에 본 연구에서는 디지털 네이티브 세대를 위한 유튜브 리터러시란 무엇인지 규명하고, 공통적으로 고려해야 할 기준을 마련하고자 하였다. 본 연구는 유튜브 리터러시 역량의 정의를 구체화하고, 어린이·청소년의 유튜브 플랫폼 활용 안내·지도 시 활용할 수 있는 체크리스트를 개발하는 것을 목적으로 한다. 이를 위하여 선행 연구와 해외사례 분석을 바탕으로 개념적 정의 및 체크리스트를 개발하였으며, 전문가 및 교육자 검토를 통하여 타당성을 확보하였다. 최종적으로 개발한 체크리스트는 미디어 접근, 비판적 이해, 미디어 참여, 윤리적 활용 4개 범주의 10개 역량, 23문항을 포함한다.

中国经济新常态下的 '新东北现象': 特征与含意 (Features and Implications of 'New Northeast Phenomenon' in China's New Normal Period)

  • 柳银河
    • 분석과 대안
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    • 제6권1호
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    • pp.259-282
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    • 2022
  • 本文关注到与过去不同的新常态下 '新东北现象' 的复合特征,着重阐述最近 '新东北现象' 里的主要三个现象-经济现象, 人口现象, 财政现象。2014年以来东北地区经济增速减缓虽成大问题,同其间东北有关人口状况与财政支出结构变动也很突出。总之, 2014年以后在东北地区, 经济增长衰退, 人口减少与人才流失加剧, 老龄化提速, 财政收支缺口增加与社会保障支出激增, 这些现象都同时发生, 互相影响着产生恶性循环, 新常态下的 '新东北现象' 之难点就在这复合实质。那么, 新常态下的 '新东北现象' 之如此复合特征与难点给全中国何含意? 本文提出两点。第一, 基于近来中国一些有关状况变化趋势来看, 东北可以被视为中国的一个缩影, 新常态下的 '新东北现象' 不限于东北地区, 不久将来很可能扩散到中国其他区域, 会成为全中国现象。第二, 新常态下的 '新东北现象' 出现, 对于改革开发以来实行的西部大开发战略, 中部崛起战略, 东北振兴战略等一系列区域大开发战略的根本性效果, 要求深刻的反思且重新构想。这些区域发展战略, 虽有所成就, 中西部地区, 尤其是西部, 还仍然相对很落后, 中国区域差距一向没有缩小。振兴东北战略实行已有了20来年, 新常态下的 '新东北现象' 出现也显示长期以来困扰东北经济的深层次问题始终没有得到解决。近来习进平格外强调 '共同富裕', '新东北现象' 也成为本届中央政府最急切解决的问题之一, 如果成功了, 既能为重新构思和调整区域发展战略提出有效方向, 又能为对应未来中国经济社会变动成为一个重要标志。

State-Based Behavior Modeling in Software and Systems Engineering

  • Sabah Al-Fedaghi
    • International Journal of Computer Science & Network Security
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    • 제23권5호
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    • pp.21-32
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    • 2023
  • The design of complex man-made systems mostly involves a conceptual modeling phase; therefore, it is important to ensure an appropriate analysis method for these models. A key concept for such analysis is the development of a diagramming technique (e.g., UML) because diagrams can describe entities and processes and emphasize important aspects of the systems being described. The analysis also includes an examination of ontological concepts such as states and events, which are used as a basis for the modeling process. Studying fundamental concepts allows us to understand more deeply the relationship between these concepts and modeling frameworks. In this paper, we critically analyze the classic definition of a state utilizing the Thinging machine (TM) model. States in state machine diagrams are considered the appropriate basis for modeling system behavioral aspects. Despite its wide application in hardware design, the integration of a state machine model into a software system's modeling requirements increased the difficulty of graphical representation (e.g., integration between structural and behavioral diagrams). To understand such a problem, in this paper, we project (create an equivalent representation of) states in TM machines. As a case study, we re-modeled a state machine of an assembly line system in a TM. Additionally, we added possible triggers (transitions) of the given states to the TM representation. The outcome is a complicated picture of assembly line behavior. Therefore, as an alternative solution, we re-modeled the assembly line based solely on the TM. This new model presents a clear contrast between state-based modeling of assembly line behavior and the TM approach. The TM modeling seems more systematic than its counterpart, the state machine, and its notions are well defined. In a TM, states are just compound events. A model of a more complex system than the one in the assembly line has strengthened such a conclusion.

A modified JFNK with line search method for solving k-eigenvalue neutronics problems with thermal-hydraulics feedback

  • Lixun Liu;Han Zhang;Yingjie Wu;Baokun Liu;Jiong Guo;Fu Li
    • Nuclear Engineering and Technology
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    • 제55권1호
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    • pp.310-323
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    • 2023
  • The k-eigenvalue neutronics/thermal-hydraulics coupling calculation is a key issue for reactor design and analysis. Jacobian-free Newton-Krylov (JFNK) method, featured with super-linear convergence rate and high efficiency, has been attracting more and more attention to solve the multi-physics coupling problem. However, it may converge to the high-order eigenmode because of the multiple solutions nature of the k-eigenvalue form of multi-physics coupling issue. Based on our previous work, a modified JFNK with a line search method is proposed in this work, which can find the fundamental eigenmode together with thermal-hydraulics feedback in a wide range of initial values. In detail, the existing modified JFNK method is combined with the line search strategy, so that the intermediate iterative solution can avoid a sudden divergence and be adjusted into a convergence basin smoothly. Two simplified 2-D homogeneous reactor models, a PWR model, and an HTR model, are utilized to evaluate the performance of the newly proposed JFNK method. The results show that the performance of this proposed JFNK is more robust than the existing JFNK-based methods.

배선을 최소화한 XOR 게이트 기반의 QCA 반가산기 설계 (Design Of Minimized Wiring XOR gate based QCA Half Adder)

  • 남지현;전준철
    • 예술인문사회 융합 멀티미디어 논문지
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    • 제7권10호
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    • pp.895-903
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    • 2017
  • 양자점 셀룰라 오토마타(QCA)는 CMOS의 근본적인 한계에 대한 대체 해결책으로 제안된 기술 중 하나이다. QCA는 최근 실험 결과와 함께 다양한 연구가 진행해오고 있으며 나노 규모의 크기와 낮은 전력 소비로 각광 받고 있다. 기존 논문에서 제안된 XOR 게이트는 최소한의 면적과 셀의 개수를 이용하여 설계 할 수 있음에도 불구하고 안정성 및 결과의 정확성 때문에 추가된 셀의 개수가 많았다. 본 논문에서는 기존의 XOR 게이트의 단점을 보완한 게이트를 제안한다. 본 논문의 XOR 게이트는 정사각형 구조로 AND 게이트와 OR게이트를 배치함으로써 셀 배선의 개수를 줄인다. 그리고 제안한 XOR 게이트를 이용하여 단순 인버터 역할을 하는 셀 2개를 추가해 반가산기를 제안한다. 또한 본 논문은 입력과 결과의 정확성을 위해 QCADesginer을 이용한다. 따라서 제안한 반가산기는 기존의 반가산기에 비해 더 적은 수의 셀, 전체 면적으로 구성됨으로 큰 회로에 사용할 때 혹은 작은 면적에 반가산기가 필요할 때 효율적이다.

Hyundai Motor's Global Marketing Strategy: "New Thinking. New Possibilities."

  • Kang, Wooseong;Kim, Youngchan;Yoo, Changjo
    • Asia Marketing Journal
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    • 제16권1호
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    • pp.215-228
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    • 2014
  • The automotive industry plays a significant role in the global economy. One of the reasons is that this industry compasses every aspects of the value chain - from raw materials to design and development, manufacturing, sales and services, and even disposal. Thus, the industry needs significant upfront capital investment and requires years of R&D and market development. As a result, this industry is dominated by a handful of global players and it is not easy for a new entrant to enter this industry. Furthermore, success is even more difficult to achieve. How did Hyundai Motor make it in this tough marketplace? Can it continue against all odds? The CAGR for last 5 years is 12% and it stands at 6th in the world. Compared to other global brands, Hyundai has geographically well-balanced sales portfolio. The quality improvement is outstanding. The brand performance follows these quality and sales improvements. Yet, the global competition is ever intensifying. Now, it is the time to step up once more. The next strategic goal needs fundamental shift toward brand and marketing-focus. In constructing global marketing strategy, Hyundai Motor's vision is "Lifetime partner in mobility and beyond" and its goal is global top 3 brand by year 2015 through modern premium brand image and selling 5 million vehicles. The target brand positioning of Hyundai Motor is the leading position in premium dimension and stylish/modern dimension. The global brand strategy framework is based on the brand direction of "Modern Premium" and is designed to deliver core brand identity (i.e., Simple, Creative, Caring) to customers. In order to manage brand performance, Hyundai's marketing platformalso includes marketing performance management, brand performance management, and market driven organization. From this diagnosis, Hyundai Motor is well posed to build a strong brand. Nevertheless, there are still challenges ahead from consumer, technology, competitor, and macro-environment perspectives. To overcome these threats, the bases of competition for all successful automotive brands are various differentiation factors, including technology, performance, value proposition, or heritage. Hyundai Motor is well prepared so far. However, it is not tested against time yet whether Hyundai can overcome these unforeseeable major threats. Hyundai is trying to find the solution from a strong brand, while believing in "New Thinking. New Possibilities."

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A Trend Analysis on E-sports using Social Big Data

  • Kyoung Ah YEO;Min Soo KIM
    • Journal of Sport and Applied Science
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    • 제8권1호
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    • pp.11-17
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    • 2024
  • Purpose: The purpose of the study was to understand a trend of esports in terms of gamers' and fans' perceptions toward esports using social big data. Research design, data, and methodology: In this study, researchers first selected keywords related to esports. Then a total of 10,138 buzz data created at twitter, Facebook, news media, blogs, café and community between November 10, 2022 and November 19, 2023 were collected and analyzed with 'Textom', a big data solution. Results: The results of this study were as follows. Firstly, the news data's main articles were about competitions hosted by local governments and policies to revitalize the gaming industry. Secondly, As a result of esports analysis using Textom, there was a lot of interest in the adoption of the Hangzhou Asian Games as an official event and various esports competitions. As a result of the sentiment analysis, the positive content was related to the development potential of the esports industry, and the negative content was a discussion about the fundamental problem of whether esports is truly a sport. Thirdly, As a result of analyzing social big data on esports and the Olympics, there was hope that it would be adopted as an official event in the Olympics due to its adoption as an official event in the Hangzhou Asian Games. Conclusions: There was a positive opinion that the adoption of esports as an official Olympic event had positive content that could improve the quality of the game, and a negative opinion that games with actions that violate the Olympic spirit, such as murder and assault, should not be adopted as an official Olympic event. Further implications were discussed.

On the free vibration behavior of carbon nanotube reinforced nanocomposite shells: A novel integral higher order shear theory approach

  • Mohammed Houssem Eddine Guerine;Zakaria Belabed;Abdelouahed Tounsi;Sherain M.Y. Mohamed;Saad Althobaiti;Mahmoud M. Selim
    • Structural Engineering and Mechanics
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    • 제91권1호
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    • pp.1-23
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    • 2024
  • This paper formulates a new integral shear deformation shell theory to investigate the free vibration response of carbon nanotube (CNT) reinforced structures with only four independent variables, unlike existing shell theories, which invariably and implicitly induce a host of unknowns. This approach guarantees traction-free boundary conditions without shear correction factors, using a non-polynomial hyperbolic warping function for transverse shear deformation and stress. By introducing undetermined integral terms, it will be possible to derive the motion equations with a low order of differentiation, which can facilitate a closed-form solution in conjunction with Navier's procedure. The mechanical properties of the CNT reinforcements are modeled to vary smoothly and gradually through the thickness coordinate, exhibiting different distribution patterns. A comparison study is performed to prove the efficacy of the formulated shell theory via obtained results from existing literature. Further numerical investigations are current and comprehensive in detailing the effects of CNT distribution patterns, volume fractions, and geometrical configurations on the fundamental frequencies of CNT-reinforced nanocomposite shells present here. The current shell theory is assumed to serve as a potent conceptual framework for designing reinforced structures and assessing their mechanical behavior.