• 제목/요약/키워드: Direct Problem

검색결과 1,545건 처리시간 0.031초

전이학습과 k-means clustering의 융합을 통한 콘크리트 결함 탐지 성능 향상에 대한 연구 (A study on the improvement of concrete defect detection performance through the convergence of transfer learning and k-means clustering)

  • 윤영근;오태근
    • 문화기술의 융합
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    • 제9권2호
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    • pp.561-568
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    • 2023
  • 콘크리트 구조물은 대내외적 환경에 의해 다양한 결함이 발생한다. 결함이 있는 경우 콘크리트의 구조적 안전성에 문제가 있어 이를 효율적으로 파악하여 유지관리하는 것이 중요하다. 하지만, 최근 딥러닝 연구는 콘크리트의 균열에 초점이 맞추어져 있어, 박락과 오염 등에 대한 연구는 부족하다. 본 연구에서는 라벨링이 어려운 박락과 오염에 초점을 맞추어 언라벨 방법, 필터링 방법, 전이학습과 k-means cluster의 융합을 통한 4개의 모델을 개발하고 성능을 평가하였다. 분석결과, 융합모델이 결함을 가장 세밀하게 구분하였으며, 직접 라벨링을 하는 것보다 효율성을 증가시킬 수 있었다. 본 연구 결과가 향후 라벨링이 어려운 다양한 결함 유형에 대한 딥러닝 모델 개발에 기여할 수 있기를 기대한다.

생애주기 성능 및 비용에 기초한 교량 유지관리기법 개발 (Development of Bridge Maintenance Method based on Life-Cycle Performance and Cost)

  • 박경훈;공정식;황윤국;조효남
    • 대한토목학회논문집
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    • 제26권6A호
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    • pp.1023-1032
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    • 2006
  • 본 논문에서는 기존 교량 유지관리방법의 한계를 극복하고 예방유지관리 체계의 구현을 위하여 새로운 교량 유지관리기법을 제안하였다. 제안된 방법은 생애주기비용뿐만 아니라 생애주기성능을 함께 고려하여 열화되는 교량의 최적 유지관리전략을 수립할 수 있다. 교량의 성능변화는 신뢰성에 기초한 안전도와 상태등급을 세분화한 상태지수에 의해 평가되며, 생애주기 비용은 직접유지관리비용뿐만 아니라 도로이용자비용과 파손비용을 고려하여 추정하였다. 교량수명 동안의 성능 및 비용과 관련된 다중목적 조합 최적화 문제인 교량 유지관리 시나리오 집합의 생성을 위해 유전자알고리즘을 적용하였다. 개발된 방법을 실교량에 적용하여 유지관리전략 수립의 과정과 효과를 고찰하였다. 이러한 결과를 통해, 개발된 방법은 유지관리를 위한 의사결정과정에 효과적으로 활용될 수 있을 것으로 판단된다.

몰드 두께에 의한 팬 아웃 웨이퍼 레벨 패키지의 Warpage 분석 (Analysis of Warpage of Fan-out Wafer Level Package According to Molding Process Thickness)

  • 문승준;김재경;전의식
    • 반도체디스플레이기술학회지
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    • 제22권4호
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    • pp.124-130
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    • 2023
  • Recently, fan out wafer level packaging, which enables high integration, miniaturization, and low cost, is being rapidly applied in the semiconductor industry. In particular, FOWLP is attracting attention in the mobile and Internet of Things fields, and is recognized as a core technology that will lead to technological advancements such as 5G, self-driving cars, and artificial intelligence in the future. However, as chip density and package size within the package increase, FOWLP warpage is emerging as a major problem. These problems have a direct impact on the reliability and electrical performance of semiconductor products, and in particular, cause defects such as vacuum leakage in the manufacturing process or lack of focus in the photolithography process, so technical demands for solving them are increasing. In this paper, warpage simulation according to the thickness of FOWLP material was performed using finite element analysis. The thickness range was based on the history of similar packages, and as a factor causing warpage, the curing temperature of the materials undergoing the curing process was applied and the difference in deformation due to the difference in thermal expansion coefficient between materials was used. At this time, the stacking order was reflected to reproduce warpage behavior similar to reality. After performing finite element analysis, the influence of each variable on causing warpage was defined, and based on this, it was confirmed that warpage was controlled as intended through design modifications.

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Development of Message Broker-Based Real-Time Control Method for Road Traffic Safety Facilities Equipment and Devices Integrated Management System

  • JeongHo Kho;Eum Han
    • 한국컴퓨터정보학회논문지
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    • 제29권1호
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    • pp.195-209
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    • 2024
  • 1990년대 개발되어 현재의 모습을 갖춘 교통신호제어기는 최근 도로 이용자의 교통안전 향상 및 자율협력주행 등을 목적으로 설치되는 다양한 장치들에 대한 전원공급 문제와 다양한 통신방식, 계층화된 블랙박스 구조 등으로 인해 유연성과 확장성에 한계를 가지고 있다. 이에 본 논문에서는 이더넷전원장치(PoE : Power over Ethernet) 기술을 통해 직류(DC) 전원 사용과 전원공급 문제를 해결하고, 메시지 브로커(Message Broker) 기술을 통해 중앙화된 데이터 기반 제어를 함으로써 빠르게 변화하는 미래 교통환경에 대응이 가능한 교통안전시설 통합관제시스템을 설계하였다. 또한 시계열 데이터를 기반으로 동작하는 교통안전시설 장치를 위한 데이터 기반 실시간 제어 방안을 구현하고 검증하였다.

Effect of Perioperative Prophylactic Intravenous Antibiotic Use in Immediate Implant-Based Breast Reconstruction: A Retrospective Matched Cohort Study

  • Seok Kyung In;Seok Won Park;Yujin Myung
    • Archives of Plastic Surgery
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    • 제51권1호
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    • pp.36-41
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    • 2024
  • Background Among breast reconstruction methods, implant-based breast reconstruction has become the mainstream. However, periprosthetic infection is still an unresolved problem. Although published articles have revealed that limited use of antibiotics is sufficient to reduce infection rates, the number of surgeons still preferring elongated usage of antibiotics is not less. The aim of our study is to validate the appropriate duration of antibiotic use to reduce infection rate after implant-based breast reconstruction. Methods A retrospective study reviewed medical record of 235 patients (274 implants for reconstruction) who underwent prepectoral direct to implant breast reconstruction using acellular dermal matrix wrapping technique. Infection rates were analyzed for the patients administered postoperative prophylactic antibiotics until drain removal and those who received only perioperative prophylactic antibiotics for 24 hours. Results Of the 274 implants, 98 who were administered prophylactic antibiotics until drain removal had an infection rate of 3.06% (three implants) and 176 who received prophylactic antibiotics no longer than 24 hours postoperatively had an infection rate of 4.49% (eight implants). A total of 11 patients diagnosed with postoperative infection clinically, 8 were salvaged by antibiotic treatment, and 3 had implant removal and replacement with autologous flap. Postoperative antibiotic prophylaxis duration had no statistically significant effects in the risk of infection (p = 0.549). Conclusion The duration of prophylactic antibiotics after surgery was not related to infection risk. Further study with a large number of patients, randomized control study, and route of antibiotics is needed.

Assessment of nonlocal nonlinear free vibration of bi-directional functionally-graded Timoshenko nanobeams

  • Elnaz Zare;Daria K. Voronkova;Omid Faraji;Hamidreza Aghajanirefah;Hamid Malek Nia;Mohammad Gholami;Mojtaba Gorji Azandariani
    • Advances in nano research
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    • 제16권5호
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    • pp.473-487
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    • 2024
  • The current study employs the nonlocal Timoshenko beam (NTB) theory and von-Kármán's geometric nonlinearity to develop a non-classic beam model for evaluating the nonlinear free vibration of bi-directional functionally-graded (BFG) nanobeams. In order to avoid the stretching-bending coupling in the equations of motion, the problem is formulated based on the physical middle surface. The governing equations of motion and the relevant boundary conditions have been determined using Hamilton's principle, followed by discretization using the differential quadrature method (DQM). To determine the frequencies of nonlinear vibrations in the BFG nanobeams, a direct iterative algorithm is used for solving the discretized underlying equations. The model verification is conducted by making a comparison between the obtained results and benchmark results reported in prior studies. In the present work, the effects of amplitude ratio, nanobeam length, material distribution, nonlocality, and boundary conditions are examined on the nonlinear frequency of BFG nanobeams through a parametric study. As a main result, it is observed that the nonlinear vibration frequencies are greater than the linear vibration frequencies for the same amplitude of the nonlinear oscillator. The study finds that the difference between the dimensionless linear frequency and the nonlinear frequency is smaller for CC nanobeams compared to SS nanobeams, particularly within the α range of 0 to 1.5, where the impact of geometric nonlinearity on CC nanobeams can be disregarded. Furthermore, the nonlinear frequency ratio exhibits an increasing trend as the parameter µ is incremented, with a diminishing dependency on nanobeam length (L). Additionally, it is established that as the nanobeam length increases, a critical point is reached at which a sharp rise in the nonlinear frequency ratio occurs, particularly within the nanobeam length range of 10 nm to 30 nm. These findings collectively contribute to a comprehensive understanding of the nonlinear vibration behavior of BFG nanobeams in relation to various parameters.

배관내 압력변동 신호를 이용한 유량 추정 방법 연구 (A Study on Flow Rate Estimation Using Pressure Fluctuation Signals in Pipe)

  • 이정한;장대식;박진호
    • 한국압력기기공학회 논문집
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    • 제19권2호
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    • pp.155-162
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    • 2023
  • In nuclear power plants, the flow rate information is a major indicator of the performance of rotating equipment such as pumps, and is a very important one required for facility operation and maintenance. To measure a flow rate, various types of methods have been developed and used. Among them, the differential pressure type using orifice and the direct doppler type using ultrasonic waves are the most commonly used. However, these flow rate measurement methods have limitations in installation, conditions and status of the measuring part, etc. To solve this problem, we have studied a new technique for measuring flow rate from scratch. In this paper, we have devised a technique to estimate the flow rate using an average moving velocity of large-scale eddy in turbulence that occurs in the piping flow field. The velocity of the large-scale eddy can be measured using the pressure fluctuation signals on the inner surface of the pipe. To estimate the flow rate, at first a cross-correlation function is applied to the two pressure fluctuation signals located at different positions in the down stream for calculating the time delay between the moving eddies. In order to validate the proposed flow rate estimation method, CFD analyses for the internal turbulence flow in pipe are conducted with a fixed flow condition, where the pressure fluctuation signals on the pipe inner surface are simulated. And then the average flow velocity of the large scale eddy is to be estimated. The estimated flow velocity is turned out to be similar to the fixed (known) flow rate.

성인의 스트레스, 사회적 지원과 대처: 자기효능감 수준별 분석 (Stress, Social Support and Coping of Adults According to Level of Self-Efficacy)

  • 박영신;손주연;송옥란
    • 한국심리학회지 : 문화 및 사회문제
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    • 제23권2호
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    • pp.295-332
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    • 2017
  • 이 연구는 자기효능감 수준별 성인의 스트레스, 사회적 지원과 대처의 차이를 규명하는데 주된 목적이 있다. 분석대상은 초, 중, 고등학생 자녀를 둔 성인 899명(남 399, 여: 500)이었다. 자유반응문항에 대한 채점자간 신뢰도는 93.4%, Kappa 계수는 .920이었으며, 양적 측정변인의 신뢰도는 α=.87~.92이었다. 분석결과, 첫째, 성인의 스트레스 생활사건으로 경제적 어려움이 가장 대표적이고 그 다음으로 자녀 양육, 직장 업무 등이 포함되었는데, 자기효능감 하집단이 상집단보다 경제적 어려움을 많이 지적하였다. 자기효능감 수준별 스트레스 증상에서 유의한 차이가 있었는데, 자기효능감 하집단이 상집단보다 스트레스 증상이 강하였다. 둘째, 스트레스 상황에서 사회적 지원 제공자는 가족이 가장 대표적이었고, 이외에 자기자신, 친구 등의 순서로 포함되었는데, 자기효능감 상집단은 가족의 지원을 가장 많이 받는 반면에, 하집단은 사회적 지원 없이 자기자신이 해결하는 경우가 가장 많았다. 자기효능감 수준별 인간관계에서 유의한 차이가 있었는데, 자기효능감 상집단이 하집단보다 부모자녀관계와 부부관계 및 직장상사관계에서 갈등이 적었다. 셋째, 스트레스 상황에서 사회적 지원 유형으로는 정서적 지원이 가장 대표적이었으며, 그 다음으로 도움 없음, 조언 등이 포함되었는데, 자기효능감하집단은 상집단보다 도움없음이, 상집단은 하집단보다 조언의 비율이 상대적으로 높았다. 자기효능감 수준별 정서적 지원에서 유의한 차이가 있었는데, 자기효능감 상집단이 하집단보다 배우자나 직장상사로부터 정서적 지원을 많이 받았다. 넷째, 스트레스 상황에서 대처방법으로 자기조절, 직접적 문제 해결, 없음 등이 부각되었는데, 자기효능감 상집단은 직접적 문제 해결이, 하집단은 대처방법 없음이 가장 많았다. 자기효능감 수준별 스트레스 대처에서 유의한 차이가 있었는데, 자기효능감 상집단이 하집단보다 스트레스 대처를 더 잘 하였다.

환경 인쇄 기술의 발전과 인쇄물의 $CO_2$ 발생량에 관한 연구 (A Study about Development of Environment Printing Technology and $CO_2$)

  • 이문학
    • 한국인쇄학회지
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    • 제30권3호
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    • pp.89-114
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    • 2012
  • For as to world, the concern about the environment problem is enhanced than any other time in the past because of being 21 century. And the environment problem is highlighted as the world-wide issue. The time of the environment problem intimidates the alive of the mankind and presence of an earth over the time. It becomes the essentiality not being selection in the personal living or the economical viewpoint now to prepare for the climatic modification. As to the company management, the green growth period which it excludes the environment management considering an environment, cannot carry on the company the continued management comes. That is, in the change center of the management paradigm, there is the environment management. Nearly, the greenhouse gas which the publication industry is the environmental toxic material like all industries is generated. The greenhouse gas is ejected in the process of running the manufacturing process and print shop of the various kinds material used as the raw material of the book. Particularly, the tree felling for getting the material of the paper is known to reach the direct influence on the global warming. This study does according to an object it considers and organizes the environment parameter based on this kind of fact as to the publication industry. And it is determined as the reference which is used as the basic materials preparing the case that carbon exhaust right transaction(CAP and TRADE) drawing are enforced in all industries and is sustainable the management of the publication industry and reduces the environmental risk among the company many risk management elements and plans and enforces the publication related policy that there is a value. In the printing publication industry, this study tried to inquire into elements discharging the environmental pollutant or the greenhouse gas. Additionally, in the printed publication production process, it tried to inquire into the effort for an environment-friendly and necessity at the printing paper and the printers ink, regarded as the element discharging the greenhouse gas all kinds of the printing materials, operation of the print shop and all kinds of the machines and recycle process, and etc. These considerations make these industrial field employees aware of the significance about a conservation and environmental protection. They try to give a help in the subsequent study producing quantitatively each environmental parameter emission of green house gas. This makes the calculation of the relative $CO_2$ output reproached ultimately possible. Meanwhile, in a sense, many research protects and improving an environment in connection with the contents of research at the printing publication industrial field is in progress. There will be the voluntary human face that it has to protect an environment but this can not do by the outside factor according to all kinds of environment related law and regulation. Anyway, because of acting on company management as the factor of oppression, the increase of this environment-related correspondence cost could know that the research that the environment loading relates with a procurement and development, environment management system introduction, quality control standard, including, normalizing including a material, and etc. through the part of the effort to reduce the cost low was actively in progress. As to the green growth era, as follows, this paper prescribed the subject and alternative of the print publication industry. It is surrounded by the firstly new digital environment and the generation of the subject. And secondly the printing industry is caused by the point of time when the green growth leaves by the topic which is largest in the global industry and it increases. The printing publication industry has to prepare the bridgehead for the environment-friendly green growth as the alternative for this resolution with first. The support blown in each industry becomes the obligation not being selection. Prestek in which the print publishing was exposed to spend many energies and which is known as the practice of the sustainable print publishing insisted that it mentioned importance of the green printing through the white pages in 2008 and a company had to be the green growth comprised through the environment-friendly activity. The core management for the sustainable printing publication industry presented from Presstack white pages is compacted to 4 words that it is a remove, reduce, recover, and recycle. Second, positively the digital printing(POD) system should be utilized. In the worldwide print out market, the digital printing area stops at the level of 10% or so but the change over and growth of the market of an analog-to-digital will increase rapidly in the future. As to the CEO Jeff Hayes of the Infoland, the offset print referred to that it of the traditional method got old and infirm with the minor phase of the new printing application like the customer to be wanted publication and the print of the digital method led the market. In conclusion, print publishers have to grasp well the market flow in the situation where a digitalization cannot be generalized and a support cannot avoid. And it keeps pace with the flow of the digital age and the recognition about the effort for the development and environment problem have to be raised. Particularly, the active green strategy is employed for the active green strategy.

중소기업의 디자인 경영 전략을 위한 실증 분석연구 (A study an actual proof analysis for design management strategy of minor enterprise)

  • 홍성수;박재연
    • 감성과학
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    • 제7권1호
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    • pp.65-81
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    • 2004
  • 21세기가 도래하면서 지식화, 정보화, 기술화 등 중소기업을 둘러싼 경영 환경은 급변하고 있다. 이와 같이 급변하는 기업 환경은 대기업보다 신축적이고 탄력적인 중소기업에 보다 유리한 환경이라고 볼 수 있다. 또한 21세기의 명실상부한 창조성을 갖춘 중소기업이 산업발전의 주역으로 등장할 수 있는 경영환경으로 인식되어진다. 중소기업이 국민경제에 차지하는 비중과 역할은 매우 중요하다. 지방자치제의 실시와 지역 경제의 활성화 시책 등은 일반적으로 그 지역 사회를 존립기반으로 하고 있는 중소기업의 지위를 더욱 증대시키게 될 것이다. 그러나 디자이너 입장에서는 경영자에게 산업디자인의 효과적 활용방법이나 그 유효성 등을 충분히 인식시키거나 이해시키지 못한 문제점도 많은 것으로 지적되고 있다. 그럼에도 불구하고 정부시책으로 수많은 국내 중소기업이 비교적 단기간 내에 자사제품의 경쟁력 향상을 위한 수단으로 산업디자인을 활용하게 되었으며, 아울러 경영자 및 산업디자이너 양자가 현실적인 면에서 산업디자인에 대한 인식을 새롭게 하거나 그 유효성이나 문제점 등을 평가해 볼 수 있는 계기가 마련된 일은 매우 중요한 의미를 갖는다. 이러한 인식 하에서 본 연구는 국내 중소기업이 디자인을 경영레벨에서 전략적으로 활용하고 있는지, 디자인 경영 전략 구축은 잘 실행되고 있는지, 실무 디자이너와 CEO의 디자인 경영에 대한 인식 수준은 어느 정도 인지를 파악함으로써 여러 문제점들에 대한 새로운 해결 방법을 모색하고자 하는 데 본 연구의 목적이 있다. 따라서 본 연구를 위하여 디자인 실무자, 중소기업 경영 CEO등을 대상으로 설문조사와 직접면접방식으로 실증분석을 통하여 중소기업의 경쟁력을 높이기 위한 디자인의 활용과 대책을 제시하였다.

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