• 제목/요약/키워드: Critical path

검색결과 602건 처리시간 0.029초

교차 계층 설계 기법을 사용한 새로운 AODV 라우팅 프로토콜 설계 및 성능평가 (Performance Evaluation of the new AODV Routing Protocol with Cross-Layer Design Approach)

  • 장재신;위성홍
    • 한국정보통신학회논문지
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    • 제24권6호
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    • pp.768-777
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    • 2020
  • 본 논문에서는 이동 애드혹 네트워크에서 널리 사용되는 AODV 라우팅 프로토콜과 통신 노드의 이동성 때문에 발생하는 통신 경로 단절 등의 문제를 해결하기 위해 다중 경로설정을 지원하는 AODV 기법을 기반으로 개선된 다양한 연구 결과들을 분석한다. 그리고 AODV 기법이 사용하는 홉 기반 라우팅 기법의 문제점을 분석하고, 이를 개선하기 위해 홉 수를 주 메트릭으로 사용하면서 보조 메트릭으로 경로 지연시간의 합을 사용하는 새로운 C-AODV 라우팅 프로토콜을 설계하고, NS-3 네트워크 시뮬레이터에 구현하여 성능평가를 수행한다. 컴퓨터 시뮬레이션 성능평가 결과를 토대로 C-AODV 기법이 기존 AODV 기법과 비교하여 성능이 어느 정도 개선되는지 비교 분석하고 앞으로 개선할 사항 등을 제시한다.

수학과 인공지능(AI) 핵심 개념과 <인공지능 수학> 내용 체계 분석 (The Core Concepts of Mathematics for AI and An Analysis of Mathematical Contents in the Textbook)

  • 김창일;전영주
    • 한국학교수학회논문집
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    • 제24권4호
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    • pp.391-405
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    • 2021
  • 본 연구는 AI 교육을 위해 수학교과에서 다루어야 할 AI 핵심 개념으로 '데이터 수집', '데이터 표현', '데이터 분석', '최적화 및 의사결정' 4가지로 선정하였다. 이를 바탕으로 선택 중심 교육과정의 각 영역별 수학 핵심 개념 및 내용 요소와 대비하여 AI 핵심 개념에 대한 포함 여부를 조사하였다. 또한 <인공지능 수학>의 내용 체계의 적정성을 핵심 개념과 관련 학습 요소 중심으로 살펴보았다. 그 결과 첫째, <인공지능 수학>의 학습 경로를 어떻게 설정할 것인가?, 둘째, <인공지능 수학>의 성격에 관한 재정의 논의가 필요한가?, 셋째, <인공지능 수학>의 핵심 개념 선정 및 용어 선택은 적절한가?, 넷째, <인공지능 수학>의 내용 체계의 관련 학습 요소 제시는 적절한가? 등에 대한 논의가 필요하다는 시사점을 도출하였다.

Physical protection system vulnerability assessment of a small nuclear research reactor due to TNT-shaped charge impact on its reinforced concrete wall

  • Moo, Jee Hoon;Chirayath, Sunil S.;Cho, Sung Gook
    • Nuclear Engineering and Technology
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    • 제54권6호
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    • pp.2135-2146
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    • 2022
  • A nuclear energy facility is one of the most critical facilities to be safely protected during and after operation because the physical destruction of its barriers by an external attack could release radioactivity into the environment and can cause harmful effects. The barrier walls of nuclear energy facilities should be sufficiently robust to protect essential facilities from external attack or sabotage. Physical protection system (PPS) vulnerability assessment of a typical small nuclear research reactor was carried out by simulating an external attack with a tri-nitro toluene (TNT) shaped charge and results are presented. The reinforced concrete (RC) barrier wall of the research reactor located at a distance of 50 m from a TNT-shaped charge was the target of external attack. For the purpose of the impact assessment of the RC barrier wall, a finite element method (FEM) is utilized to simulate the destruction condition. The study results showed that a hole-size of diameter 342 mm at the front side and 364 mm at the back side was created on the RC barrier wall as a result of a 143.35 kg TNT-shaped charge. This aperture would be large enough to let at least one person can pass through at a time. For the purpose of the PPS vulnerability assessment, an Estimate of Adversary Sequence Interruption (EASI) model was used, which enabled the determination of most vulnerable path to the target with a probability of interruption equal to 0.43. The study showed that the RC barrier wall is vulnerable to a TNT-shaped charge impact, which could in turn reduce the effectiveness of the PPS.

빈발도와 가중치를 적용한 엣지 디바이스의 최적 이동패턴 추출 (Extraction of Optimal Moving Patterns of Edge Devices Using Frequencies and Weights)

  • 이연식;장민석
    • 한국정보통신학회논문지
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    • 제26권5호
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    • pp.786-792
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    • 2022
  • 최근 클라우드 환경의 서비스 지연문제 해결을 위하여 응용서비스의 사용자 근접성 확보 및 계산 오프로딩을 위한 FEC (Fog/Edge Computing) 패러다임에 대한 연구가 활발하다. 엣지 디바이스 (이동객체)들의 동적 위치변화 패턴 예측방법은 FEC 환경에서 컴퓨팅 리소스의 효율적 분배 및 배치를 위하여 중요한 역할을 한다. 본 논문은 엣지 디바이스들의 이동 빈발패턴에 대한 지지도의 임계값을 적용하여 선택된 경로들을 대상으로 임의의 가중치 (거리, 시간, 혼잡도)를 추가적으로 적용한 최적 이동패턴 추출방법을 제안한다. 실험을 통하여 제안 알고리즘은 빈발도만을 적용한 OPE_freq [8] 알고리즘과 A* 및 Dijkstra 알고리즘 등과 비교한 결과, 수행시간과 노드 접근횟수를 감소시키고 보다 정확한 경로를 추출함을 알 수 있다.

Mechanical properties of tailings with dipping interlayers under high confining pressure

  • Qinglin, Chen;Zugui, Li;Zeyu, Dai;Xiaojun, Wang;Chao, Zhang
    • Geomechanics and Engineering
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    • 제31권6호
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    • pp.557-571
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    • 2022
  • Landslides are often triggered by weak interlayers initiated in tailings dam foundations, and hazards gradually occur. This is serious for landslides in high tailings dams due to their high potential energy. Tailing samples with a fine-grained interlayer at a set dip angle were prepared. Consolidated undrained (CU) triaxial shear tests were carried out by using a high-pressure triaxial apparatus. The results were compared with the results under a low confining pressure. Four reasons were summarized for high tailings dams more prone to instability than low dams. The shear strength of the samples with dipping interlayers decreases with increasing dip angle. An obvious straight drop in the stress path after the peak occurs in samples with dipping interlayers at an angle of 60°. The effect of the interlayer on the mechanical behaviour of tailings is very sensitive, especially for the sample with a dipping interlayer at an angle of 60°. Shear slipping along the interlayer should be given more attention in tailings dams. Compared with the results under low confining pressure, the stress decreases continuously for the samples with dipping interlayers at large angles under high confining pressure. The positive pore pressure, which reduces the effective stress, occurred in tailings samples under high confining pressure. The residual strength of tailings under high confining pressure is smaller than that under low confining pressure. These factors increase the dam break risk and the disaster impact for high tailings dams.

비선형 보간법을 이용한 수중 이미지 소나의 3 차원 해저지형 실시간 생성기법 (Real-time Data Enhancement of 3D Underwater Terrain Map Using Nonlinear Interpolation on Image Sonar)

  • 이인규;김재선;노세환;신기철;이재준;유선철
    • 센서학회지
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    • 제32권2호
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    • pp.110-117
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    • 2023
  • Reconstructing underwater geometry in real time with forward-looking sonar is critical for applications such as localization, mapping, and path planning. Geometrical data must be repeatedly calculated and overwritten in real time because the reliability of the acoustic data is affected by various factors. Moreover, scattering of signal data during the coordinate conversion process may lead to geometrical errors, which lowers the accuracy of the information obtained by the sensor system. In this study, we propose a three-step data processing method with low computational cost for real-time operation. First, the number of data points to be interpolated is determined with respect to the distance between each point and the size of the data grid in a Cartesian coordinate system. Then, the data are processed with a nonlinear interpolation so that they exhibit linear properties in the coordinate system. Finally, the data are transformed based on variations in the position and orientation of the sonar over time. The results of an evaluation of our proposed approach in a simulation show that the nonlinear interpolation operation constructed a continuous underwater geometry dataset with low geometrical error.

소규모 건설회사의 공정관리 현황과 대학의 공정관리 교육방안 (Time Management Status of Small Contractors and Suggestions on Education for Time Management in Colleges)

  • 장명훈;이용규
    • 예술인문사회 융합 멀티미디어 논문지
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    • 제6권3호
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    • pp.413-422
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    • 2016
  • 공사관리자는 가용자원을 최대한 합리적으로 사용하고 주어진 공사기간과 예산 범위 내에서 건설 프로젝트를 완료하기 위해 노력하며, 공사기간 내에 프로젝트를 끝내기 위해 바차트나 CPM과 같은 공정표를 활용한다. 제주지역의 소규모 건설회사나 현장에서는 건설공사를 수행하기 위한 도구로 공정관리 전문 소프트웨어보다는 엑셀을 많이 사용하는 것으로 조사되었다. 이는 엑셀이 원가와 연계하여 사용하기 편리하고 공정관리 소프트웨어를 활용할 전문가도 부족하기 때문이다. 대학은 지역의 중소규모 건설회사가 요구하는 공정관리 능력을 가진 인재를 배출하고 있지만 교육의 질적 및 양적 측면에서 다소 부족하다. 지방 국립대 건축공학의 교육과정 조사에 의하면 대부분의 학과는 공정관리과목이나 유사한 과목을 편성하고 있다. 주요 교육내용은 네트웍 공정관리기법에 대한 이해와 공정표 작성으로 이루어져 있다. 공정관리 소프트웨어에 대한 교육과 실습은 일부 대학에서만 이루어지고 있으므로 중소규모 건설현장의 공정관리 전문가를 양성하기 위해서는 바차트 활용과 전문 공정관리 소프트웨어 교육도 필요하다.

Constructing Southeast Asia and the Middle East: Two Corners of the "Victorian World"

  • Keck, Stephen L.
    • 수완나부미
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    • 제7권2호
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    • pp.27-56
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    • 2015
  • How should we conceptualize regions? What is the context in which new approaches to regional study take place? What is the role of historical change in the reconceptualization of regions or areas? This article addresses this issue by using two case studies to shed light on the history of regional study by comparing some of the ways in which the Middle East and Southeast Asia have been conceptualized. Accordingly, the discussion traces the ways in which these areas were understood in the 19th century by highlighting the ideas of a number of influential Victorian thinkers. The Victorians are useful because not only did British thinkers play critical roles in the shaping of modern patterns of knowledge, but their empire was global in scope, encompassing parts of both Southeast Asia and the Middle East. However, the Victorians regarded these places quite differently: Southeast Asia was frequently described as "Further India" and the Middle East was the home of the Ottoman Empire. Both of these places were at least partly understood in relation to the needs of British policy-makers, who tended to focus most of their efforts according to the needs of India-which was their most important colonial possession. The article exhibits the connections between the "Eastern Question" and end of the Ottoman Empire (and the political developments which followed) led to the creation of the concept of "Middle East". With respect to Southeast Asia, attention will be devoted to the works of Alfred Russell Wallace, Hugh Clifford, and others to see how "further India" was understood in the 19th century. In addition, it is clear that the successful deployment of the term "Southeast Asia" reflected the political needs of policy makers in wake of decolonization and the Cold War. Finally, by showing the constructive nature of regions, the article suggests one possible new path for students of Southeast Asia. If the characterization of the region is marked by arbitrary factors, it may actually point to a useful avenue of enquiry, a hermeneutic of expedience. Emphasis on the adaptive and integrative features of lived realities in Southeast Asia may well be a step beyond both the agendas of "colonial knowledge" and anti-colonial nationalism.

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이식형 흡수성 융복합 의료제품 규제 비교 연구 -미국, 유럽, 한국을 중심으로- (A Comparative Study on the Regulations on Implantable Bioabsorbable Combination Products -Focusing on the U.S., Europe and Korea-)

  • 이현정;김미혜;설주은;김수동;김주희
    • 대한의용생체공학회:의공학회지
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    • 제44권6호
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    • pp.414-427
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    • 2023
  • Implantable bioabsorbable combination products undergo inherent degradation and systemic absorption within the physiological environment, thereby streamlining the therapeutic regimen and obviating the imperative for invasive extraction procedures. This inherent property not only enhances patient convenience and therapeutic efficacy but also underpins a paradigm of support characterized by heightened safety parameters. Within the regulatory landscapes of Korea, the United States, and Europe, implantable bioabsorbable combination products are meticulously classified into distinct categories, either as pharmaceutical implants or as implantable medical devices, depending on their primary mode of action. This scholarly investigation systematically examines the regulatory frameworks governing implantable bioabsorbable combination products in South Korea, the United States, and Europe. Notable discrepancies across national jurisdictions emerge concerning regulatory specifics, including terminology, product classification, and product name associated with these products. The conspicuous absence of standardized approval regulations presents a formidable barrier to the commercialization of these advanced medical devices. This academic discourse passionately emphasizes the critical need for formulating and implementing a sophisticated regulatory framework capable of streamlining the product approval process, thereby paving the way for a seamless path to commercializing implantable bioabsorbable combination products.

Coping Mechanisms Utilized by Individuals With Drug Addiction in Overcoming Challenges During the Recovery Process: A Qualitative Meta-synthesis

  • Agus Setiawan;Junaiti Sahar;Budi Santoso;Muchtaruddin Mansyur;Syamikar Baridwan Syamsir
    • Journal of Preventive Medicine and Public Health
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    • 제57권3호
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    • pp.197-211
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    • 2024
  • Objectives: Recovery from drug addiction often poses challenges for the recovering person. The coping mechanisms employed by these individuals to resist temptations and manage stress play a key role in the healing process. This study was conducted to explore the coping strategies or techniques that individuals with addiction use to handle stress and temptation while undergoing treatment. Methods: A qualitative meta-synthesis approach was utilized to critically evaluate relevant qualitative research. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines were used for article selection, with these standards applied to 4 academic databases: Scopus, PubMed, ProQuest, and CINAHL. The present review included studies published between 2014 and 2023, selected based on pre-established inclusion criteria. The quality of the studies was assessed using the Critical Appraisal Skills Programme Qualitative Studies Checklist. This review was registered with the International Prospective Register of Systematic Reviews (PROSPERO) under the registration number CRD42024497789. Results: The analysis of 13 qualifying qualitative articles revealed 5 major themes illustrating the coping mechanisms employed in the pursuit of recovery by individuals who use drugs. These themes include seeking social support, as well as psychological coping strategies, spiritual experiences, professional interventions, and the enhancement of awareness. Conclusions: Among individuals with drug addiction, coping mechanisms are crucial for resisting stress and temptations throughout the recovery process. Healthcare professionals, as medical specialists, can establish more thorough and effective plans to support these patients on their path to recovery.