• 제목/요약/키워드: Knowledge Structures

검색결과 728건 처리시간 0.028초

IMI-힙: 상수 삽입 전이 시간 복잡도를 가진 묵시 양단 우선순위 큐 (IMI-Heap: An Implicit Double-Ended Priority Queue with Constant Insertion Amortized Time Complexity)

  • 정해재
    • 정보처리학회논문지:컴퓨터 및 통신 시스템
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    • 제8권2호
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    • pp.29-34
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    • 2019
  • 우선순위 큐은 근본적인 자료 구조 중의 하나이며 오랫동안 많은 연구가 이루어여 왔다. 본 논문에서는 IMI-힙이라고 하는 묵시 양단 우선순위 큐를 제안한다. 제안된 IMI-힙에서는 삽입에 O(1) 전이시간이 걸리고 최소값과 최대값 삭제 연산에 각각 O(logn) 시간이 걸린다. 기존에 발표된 묵시 양단 우선순위 큐는 삽입과 최소/최대값 삭제에 모두 O(logn) 시간이 걸리는 것으로 본 저자는 알고 있다. 따라서 제안된 IMI-힙은 삽입 시간 복잡도에 있어서 기존의 힙보다 우수하다.

The development of field galaxies in the first half of the cosmic history

  • Park, Minjung;Yi, Sukyoung K.
    • 천문학회보
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    • 제43권2호
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    • pp.35.3-36
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    • 2018
  • One of the most prevalent knowledge about disk galaxies, which dominate the population of the local Universe, is that they consist of stellar structures with different kinematics, such as thin disk, bulge, and halo. Therefore, investigating when and how these components develop in a galaxy is the key to understanding the evolution of galaxies. Using the NewHorizon simulation, we can resolve the detailed structures of galaxies, in the field environment, from the early Universe where star formation and mergers were most active. We first decompose stellar particles in a galaxy into a disk and a dispersion-dominated, spheroidal, component based on their orbits and then see how these components evolve in terms of mass and structure. At high redshift z~3, galaxies are mostly dispersion-dominated as stars are formed misaligned with the galactic rotational axis. At z=1~2, massive galaxies start to dominantly form disk stars, while less massive galaxies do much later. Furthermore, massive galaxies are forming thinner and larger disks with time, and the preexistent disks are heated or even disrupted to become a part of dispersion-dominated component. Thus, the mass growth of spheroidal components at later epochs is dominated by disrupted stars with disk origins and accreted stars at large radii.

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Deformation estimation of truss bridges using two-stage optimization from cameras

  • Jau-Yu Chou;Chia-Ming Chang
    • Smart Structures and Systems
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    • 제31권4호
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    • pp.409-419
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    • 2023
  • Structural integrity can be accessed from dynamic deformations of structures. Moreover, dynamic deformations can be acquired from non-contact sensors such as video cameras. Kanade-Lucas-Tomasi (KLT) algorithm is one of the commonly used methods for motion tracking. However, averaging throughout the extracted features would induce bias in the measurement. In addition, pixel-wise measurements can be converted to physical units through camera intrinsic. Still, the depth information is unreachable without prior knowledge of the space information. The assigned homogeneous coordinates would then mismatch manually selected feature points, resulting in measurement errors during coordinate transformation. In this study, a two-stage optimization method for video-based measurements is proposed. The manually selected feature points are first optimized by minimizing the errors compared with the homogeneous coordinate. Then, the optimized points are utilized for the KLT algorithm to extract displacements through inverse projection. Two additional criteria are employed to eliminate outliers from KLT, resulting in more reliable displacement responses. The second-stage optimization subsequently fine-tunes the geometry of the selected coordinates. The optimization process also considers the number of interpolation points at different depths of an image to reduce the effect of out-of-plane motions. As a result, the proposed method is numerically investigated by using a truss bridge as a physics-based graphic model (PBGM) to extract high-accuracy displacements from recorded videos under various capturing angles and structural conditions.

Research trends in the Korean Journal of Women Health Nursing from 2011 to 2021: a quantitative content analysis

  • Ju-Hee Nho;Sookkyoung Park
    • 여성건강간호학회지
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    • 제29권2호
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    • pp.128-136
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    • 2023
  • Purpose: Topic modeling is a text mining technique that extracts concepts from textual data and uncovers semantic structures and potential knowledge frameworks within context. This study aimed to identify major keywords and network structures for each major topic to discern research trends in women's health nursing published in the Korean Journal of Women Health Nursing (KJWHN) using text network analysis and topic modeling. Methods: The study targeted papers with English abstracts among 373 articles published in KJWHN from January 2011 to December 2021. Text network analysis and topic modeling were employed, and the analysis consisted of five steps: (1) data collection, (2) word extraction and refinement, (3) extraction of keywords and creation of networks, (4) network centrality analysis and key topic selection, and (5) topic modeling. Results: Six major keywords, each corresponding to a topic, were extracted through topic modeling analysis: "gynecologic neoplasms," "menopausal health," "health behavior," "infertility," "women's health in transition," and "nursing education for women." Conclusion: The latent topics from the target studies primarily focused on the health of women across all age groups. Research related to women's health is evolving with changing times and warrants further progress in the future. Future research on women's health nursing should explore various topics that reflect changes in social trends, and research methods should be diversified accordingly.

이용자 참여형 시맨틱 디지털도서관 아키텍처 설계 (Designing an Architecture for Social Semantic Digital Libraries(SSDL))

  • 오삼균;원선민
    • 한국비블리아학회지
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    • 제18권2호
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    • pp.229-251
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    • 2007
  • 정보기술 환경의 변화는 디지털 도서관에 혁신적인 변화를 촉구하고 있다. 본 연구는 온톨로지 시스템으로 구성되어 이용자 참여 협업을 적극 지원하는 디지털 도서관을 Social Semantic Digital Library(이하 SSDL)로 정의하고, 이러한 디지털 도서관에 요구되는 핵심사항과 아키텍처 모델을 제시하였다. SSDL은 메타데이터와 온톨로지를 기반으로 의미기반 정보처리를 지원함과 동시에 이용자의 참여를 통해 정보와 지식을 재생산하는 혁신적인 체제이다. 본 연구에서는 5개의 수평 계층과 2개의 수직요소로 구성되는 새로운 SSDL 모델을 제시하였다.

Morphological analysis and morphometry of the occipital condyle and its relationship to the foramen magnum, jugular foramen, and hypoglossal canal: implications for craniovertebral junction surgery

  • Pakpoom Thintharua;Vilai Chentanez
    • Anatomy and Cell Biology
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    • 제56권1호
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    • pp.61-68
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    • 2023
  • Anatomical knowledge of the occipital condyle (OC) and its relationships to surrounding structures is important for avoiding injury during craniovertebral junction (CVJ) surgeries. This study was conducted to evaluate the morphology and morphometry of OC and its relationship to foramen magnum, jugular foramen (JF), and hypoglossal canal (HC). Morphometric parameters including length, width, height, and distances from the OC to surrounding structures were measured. The oval-like condyle was the most common OC shape, representing for 33.0% of all samples. The mean length, width and height of OC were 21.3±2.4, 10.5±1.4, and 7.4±1.1 mm, respectively. Moreover, OC was classified into three types based on its length. The most common OC length in both sexes was moderate length or type II (62.5%). The mean distance between anterior tips and posterior tips of OC to basion, and opisthion were 11.5±1.4, 39.1±3.3, 25.2±2.2, and 27.4±2.7 mm, respectively. The location of intracranial orifice of HC was commonly found related to middle 1/3 of OC in 45.0%. JF was related to the anterior 2/3 of OC in 81.0%, the anterior 1/3 of OC in 12.5%, and the entire OC length in 6.5%. These morphological analysis and morphometric data should be taken into consideration before performing surgical operation to avoid CVJ instability and neurovascular structure injury.

Discovery of novel Nodosilinea species (Cyanobacteria, Nodosilineales) isolated from terrestrial habitat in Ryukyus campus, Okinawa, Japan

  • Handung Nuryadi;Shimpei Sumimoto;Shoichiro Suda
    • ALGAE
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    • 제39권2호
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    • pp.59-74
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    • 2024
  • Terrestrial cyanobacteria are extremely diverse. In urban areas, they can be found as black stains on the surface of building walls, stone monuments, or man-made structures. Many of the terrestrial cyanobacteria are still understudied. To expand knowledge of terrestrial cyanobacterial diversity, a polyphasic characterization was performed to identify 12 strains isolated from campus of University of the Ryukyus, Okinawa, Japan. Multigene phylogenetic analyses based on 16S rRNA gene and 16S-23S rRNA internal transcribed spacer (ITS) region showed that the isolated strains formed two independent subclades within Nodosilinea, and were distantly related to all described Nodosilinea species. The 16S-23S rRNA ITS secondary structures showed variations for D1-D1' and Box B domain, while V3 domain was almost identical among entire species of Nodosilinea, including the studied strains. In addition, a unique morphological character, i.e. forming nodule or spiral shape, was also observed in certain studied strains. According to polyphasic characterization, Nodosilinea coculeatus sp. nov. and Nodosilinea terrestrialis sp. nov., were proposed as two new species of terrestrial cyanobacteria from Okinawa.

Full-scale simulation of wind-driven rain and a case study to determine the rain mitigation effect of shutters

  • Krishna Sai Vutukuru;James Erwin;Arindam Gan Chowdhury
    • Wind and Structures
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    • 제38권3호
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    • pp.171-191
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    • 2024
  • Wind Driven Rain (WDR) poses a significant threat to the building environment, especially in hurricane prone regions by causing interior and content damage during tropical storms and hurricanes. The damage due to rain intrusion depends on the total amount of water that enters the building; however, owing to the use of inadequate empirical methods, the amount of water intrusion is difficult to estimate accurately. Hence, the need to achieve full-scale testing capable of realistically simulating rain intrusion is widely recognized. This paper presents results of a full-scale experimental simulation at the NHERI Wall of Wind Experimental Facility (WOW EF) aimed at obtaining realistic rain characteristics as experienced by structures during tropical storms and hurricanes. A full-scale simulation of rain in strong winds would allow testing WDR intrusion through typical building components. A study of rain intrusion through a sliding glass door is presented, which accounted for the effects of multiple wind directions, test durations and wind speeds; configurations with and without shuttering systems were also considered. The study showed that significant levels of water intrusion can occur during conditions well below current design levels. The knowledge gained through this work may enhance risk modeling pertaining to loss estimates due to WDR intrusion in buildings, and it may help quantify the potential reduction of losses due to the additional protection from shuttering systems on sliding glass doors during winds.

A scoping review of cephalometric normative data in children

  • Tuan Khang Nguyen;Akanksha Cambala;Manuela Hrit;Elizabeth A. Zimmermann
    • 대한치과교정학회지
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    • 제54권4호
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    • pp.210-228
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    • 2024
  • Objective: Understanding the orofacial characteristics and growth patterns in children is essential for both orthodontics and research on children with orofacial abnormalities. However, a concise resource of normative data on the size and relative position of these structures in different populations is not available. Our objective was to aggregate normative data to assess the growth of the orofacial skeletal structures in children with a well-balanced face and normal occlusion. Methods: The MEDLINE, Embase, and Scopus databases were searched. Inclusion criteria included longitudinal and cross-sectional studies on cephalometric measurement of skeletal tissues and a study population ≤ 18 years with a well-balanced face and normal occlusion. Key study parameters were extracted, and knowledge was synthesized. A quality appraisal was performed using a 10-point scale. Results: The final selection comprised of 12 longitudinal and 33 cross-sectional studies, the quality of which ranged from good to excellent. Our results showed that from childhood to adulthood, the length of the cranial base increased significantly while the cranial base angle remained constant; both the maxilla and mandible moved forward and downward. The profile becomes straighter with age. Conclusions: Growth patterns in children with a well-balanced face and normal occlusion follow accepted theories of growth.

입력강화와 출력강화 형태초점교수 상황에서의 한국 EFL 학습자들의 언어형태 지식개발에 관한 연구 (A Study on the Korean EFL Learners' Grammatical Knowledge Development under Input-enhanced FFI and Output-enhanced FFI Conditions)

  • 황희정
    • 디지털융복합연구
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    • 제16권5호
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    • pp.435-443
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    • 2018
  • 본 연구의 목적은 형태초점교수법이 학습자의 언어형태에 관한 지식 향상에 미치는 영향을 조사하고, 학습자들이 그 형태에 관한 지식을 출력활동인 글쓰기에 어떻게 활용하는지를 살펴보는 것이다. 연구참여자들은 122명의 대학생들로 3개의 집단 즉 입력강화집단 35명, 출력강화집단 41명, 대조집단 46명으로 나누어 평가시험과 글쓰기 과제를 사전 사후로 실시하였다. 연구결과를 살펴보면, 입력강화 형태초점교수법과 출력강화 형태초점교수법 모두 학습자의 언어형태 학습에 영향을 미치는 것으로 드러났고, 학습자들이 이러한 형태초점교수법으로 습득한 지식을 영어글쓰기에 활용하는데 기여한 것으로 나타났다. 본 연구결과에 의거하여, 학습자의 언어형태 학습의 효과를 극대화할 수 있는 방법으로 입력강화와 출력강화기법을 적절하게 결합한 형태초점교수법을 적용할 것을 제안한다.