• 제목/요약/키워드: indeterminate

검색결과 299건 처리시간 0.021초

Determination of the load carrying capacity of closed steel supports used in underground construction and mining

  • Lenka, Koubova;Petr, Janas;Karel, Janas;Martin, Krejsa
    • Steel and Composite Structures
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    • 제45권5호
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    • pp.715-728
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    • 2022
  • Closed steel supports of different shapes are used in mining and underground constructions. The supports are prefabricated from rolled, usually robust, steel profiles. The load carrying capacity of a support is considerably influenced by the active loading and passive forces. The passive forces are induced by interactions between the support and the surrounding rock mass. The analysis herein comprises three parts: The first part consists of structural geometry processing. The second part involves finding the numerical solution of a statically indeterminate structure for a specified load. The third part is calculation of the load carrying capacity and the components of internal forces and deformations. For this, the force method and numerical integration are used. The Winkler model is applied when the support interacts with the surrounding environment. The load carrying capacity is limited by the slip resistance of the connected parts and it is limited by reaching the ultimate state of the profile. This paper serves as a comprehensive reference for the determination of the load carrying capacity of closed steel supports and includes stepwise derivations of the governing formulas.

Coronoid Process Hyperplasia: A Rare Case of Restricted Mouth Opening Masquerading as Temporomandibular Disorder

  • Juhyun Cha;Jin Woo Chung
    • Journal of Oral Medicine and Pain
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    • 제48권3호
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    • pp.112-117
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    • 2023
  • Coronoid process hyperplasia (CPH) of the mandible is a rare condition in which abnormal elongation of the coronoid process leads to chronic mandibular hypomobility. CPH causes impingement or impedance of the coronoid process on the inner surface of the frontal part of the zygomatic bone during mouth opening. The lack of significant symptoms makes the diagnosis difficult. Its etiology remains inconclusive despite several theories being suggested. In this report, three reviewed cases are presented. All three patients visited our clinic with limited mouth opening as the chief complaint. Standard clinical and radiographic examinations were conducted under the initial impression of temporomandibular disorders (TMDs), and restricted jaw movements were confirmed in all cases. The absence of improved signs and symptoms following conservative treatment for TMDs or the indeterminate plain radiographs required the attending clinicians to consider three-dimensional imagery. Computed tomography revealed bilateral coronoid hyperplasia in all cases and impingement on the zygomatic bone in two of the three cases. After concluding that this condition caused the patients' limited mouth opening, the patients were referred to the Department of Oral and Maxillofacial Surgery for possible bilateral coronoidectomy or coronoidotomy. CPH usually presents no symptoms apart from a progressive reduction of mouth opening over time. Diagnosis is often delayed, and patients may undergo unnecessary treatment procedures. Clinicians should be aware of this condition and exercise caution in the differential diagnosis of patients with chronic mandibular hypomobility.

Quasi-static responses of time-dependent sandwich plates with viscoelastic honeycomb cores

  • Nasrin Jafari;Mojtaba Azhari
    • Structural Engineering and Mechanics
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    • 제88권6호
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    • pp.589-598
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    • 2023
  • This article addresses the quasi-static analysis of time-dependent honeycomb sandwich plates with various geometrical properties based on the bending analysis of elastic honeycomb sandwich plates employing a time function with three unknown coefficients. The novel point of the developed method is that the responses of viscoelastic honeycomb sandwich plates under static transversal loads are clearly formulated in the space and time domains with very low computational costs. The mechanical properties of the sandwich plates are supposed to be elastic for the faces and viscoelastic honeycomb cells for the core. The Boltzmann superposition integral with the constant bulk modulus is used for modeling the viscoelastic material. The shear effect is expressed using the first-order shear deformation theory. The displacement field is predicted by the product of a determinate geometrical function and an indeterminate time function. The simple HP cloud mesh-free method is utilized for discretizing the equations in the space domain. Two coefficients of the time function are extracted by answering the equilibrium equation at two asymptotic times. And the last coefficient is easily determined by solving the first-order linear equation. Numerical results are presented to consider the effects of geometrical properties on the displacement history of viscoelastic honeycomb sandwich plates.

Combined Hepatocellular-Cholangiocarcinoma: Changes in the 2019 World Health Organization Histological Classification System and Potential Impact on Imaging-Based Diagnosis

  • Tae-Hyung Kim;Haeryoung Kim;Ijin Joo;Jeong Min Lee
    • Korean Journal of Radiology
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    • 제21권10호
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    • pp.1115-1125
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    • 2020
  • Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a primary liver cancer (PLC) with both hepatocytic and cholangiocytic phenotypes. Recently, the World Health Organization (WHO) updated its histological classification system for cHCC-CCA. Compared to the previous WHO histological classification system, the new version no longer recognizes subtypes of cHCC-CCA with stem cell features. Furthermore, some of these cHCC-CCA subtypes with stem cell features have been recategorized as either hepatocellular carcinomas (HCCs) or intrahepatic cholangiocarcinomas (ICCs). Additionally, distinctive diagnostic terms for intermediate cell carcinomas and cholangiolocarcinomas (previous cholangiolocellular carcinoma subtype) are now recommended. It is important for radiologists to understand these changes because of its potential impact on the imaging-based diagnosis of HCC, particularly because cHCC-CCAs frequently manifest as HCC mimickers, ICC mimickers, or as indeterminate on imaging studies. Therefore, in this review, we introduce the 2019 WHO classification system for cHCC-CCA, illustrate important imaging features characteristic of its subtypes, discuss the impact on imaging-based diagnosis of HCC, and address other important considerations.

Pictorial Review of Mediastinal Masses with an Emphasis on Magnetic Resonance Imaging

  • Jin Wang Park;Won Gi Jeong;Jong Eun, Lee;Hyo-jae Lee;So Yeon Ki;Byung Chan Lee;Hyoung Ook Kim;Seul Kee Kim;Suk Hee Heo;Hyo Soon Lim;Sang Soo Shin;Woong Yoon;Yong Yeon Jeong;Yun-Hyeon Kim
    • Korean Journal of Radiology
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    • 제22권1호
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    • pp.139-154
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    • 2021
  • Magnetic resonance imaging (MRI) has become a crucial tool for evaluating mediastinal masses considering that several lesions that appear indeterminate on computed tomography and radiography can be differentiated on MRI. Using a three-compartment model to localize the mass and employing a basic knowledge of MRI, radiologists can easily diagnose mediastinal masses. Here, we review the use of MRI in evaluating mediastinal masses and present the images of various mediastinal masses categorized using the International Thymic Malignancy Interest Group's three-compartment classification system. These masses include thymic hyperplasia, thymic cyst, pericardial cyst, thymoma, mediastinal hemangioma, lymphoma, mature teratoma, bronchogenic cyst, esophageal duplication cyst, mediastinal thyroid carcinoma originating from ectopic thyroid tissue, mediastinal liposarcoma, mediastinal pancreatic pseudocyst, neurogenic tumor, meningocele, and plasmacytoma.

현대 패션에 표현된 숭고미에 관한 연구 - 1990년 이후부터 현재까지의 패션을 중심으로 - (The Sublime in Contemporary Fashion - Focused on the Fashion from the Early 90's -)

  • 최수현
    • 복식
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    • 제55권7호
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    • pp.114-130
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    • 2005
  • In postmodernism, the sublime that reaches ecstasy overcoming terror or pain is described as the most expressive phenomenon. The purpose of this study is to understand the sublime expressed in contemporary fashion. for this purpose, 1 investigated the theories of the sublime, categorized the definition and modes, then applied those categories for contemporary fashion. Documentary studies were conducted through aesthetic, design and fashion books and the demonstrative studies were processed by analyzing photos from fashion magazines. In the history of aesthetics, the sublime is explained as the ambivalent feeling mixed with pain and pleasure, terror and delight or negation and affirmation. In this study, the sublime could be defined as the aesthetic pleasure through the transcendence of the pain and terror and classified into 3 categories, the tragic, the initiative, and the deconstructive. The tragic sublime that includes the terrific, the disgusting and the religious character is expressed through the image of death or the physical torture, the satanic image or disgusting object and the ascetic image and religious sign or icons. The limitless sublime that includes the giant and the dynamic character is accomplished by consist of the elongation or the enlargement and the powerful authority. The deconsturctive sublime that includes the negative, the indeterminate and the complex character is associated with the deconstruction in style, the reversal of image and the destruction of the space of the body. Analysis on the sublime expressed in contemporary fashion may provide an excellent way for understanding human aesthetic consciousness in dress.

철근콘크리트 깊은 보 스트럿-타이 모델의 콘크리트 스트럿의 유효강도 (Effective Strengths of Concrete Struts in Strut-Tie Models of Reinforced Concrete Deep Beams)

  • 채현수;윤영묵
    • 대한토목학회논문집
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    • 제33권6호
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    • pp.2195-2209
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    • 2013
  • 스트럿-타이 모델 방법을 이용하여 철근콘크리트 깊은 보를 정확하게 해석하고 안전하게 설계하기 위해서는 콘크리트 스트럿의 유효강도를 정확하게 결정하여야 한다. 이 연구에서는 여러 설계기준서 및 연구문헌에서 제안된 세 종류의 대표적인 철근콘크리트 깊은 보의 스트럿-타이 모델을 위하여 철근콘크리트 깊은 보의 전단경간 비, 콘크리트의 압축강도, 그리고 휨철근 및 전단철근 비 등의 주요 설계변수들의 영향을 정확하게 반영할 수 있는 콘크리트 스트럿의 유효강도 식을 개발, 제안하였다. 현행 설계기준서 및 여러 연구문헌의 콘크리트 스트럿의 유효강도 식과 이 연구에서 제안한 유효강도 식을 이용하여 파괴실험이 수행된 241개 철근콘크리트 깊은 보의 극한강도를 평가하였으며, 그 결과의 비교분석을 통해 이 연구에서 제안한 스트럿 유효강도 식의 적합성을 평가하였다.

A novel four-unknown integral model for buckling response of FG sandwich plates resting on elastic foundations under various boundary conditions using Galerkin's approach

  • Chikr, Sara Chelahi;Kaci, Abdelhakim;Bousahla, Abdelmoumen Anis;Bourada, Fouad;Tounsi, Abdeldjebbar;Bedia, E.A. Adda;Mahmoud, S.R.;Benrahou, Kouider Halim;Tounsi, Abdelouahed
    • Geomechanics and Engineering
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    • 제21권5호
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    • pp.471-487
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    • 2020
  • In this work, the buckling analysis of material sandwich plates based on a two-parameter elastic foundation under various boundary conditions is investigated on the basis of a new theory of refined trigonometric shear deformation. This theory includes indeterminate integral variables and contains only four unknowns in which any shear correction factor not used, with even less than the conventional theory of first shear strain (FSDT). Applying the principle of virtual displacements, the governing equations and boundary conditions are obtained. To solve the buckling problem for different boundary conditions, Galerkin's approach is utilized for symmetric EGM sandwich plates with six different boundary conditions. A detailed numerical study is carried out to examine the influence of plate aspect ratio, elastic foundation coefficients, ratio, side-to-thickness ratio and boundary conditions on the buckling response of FGM sandwich plates. A good agreement between the results obtained and the available solutions of existing shear deformation theories that have a greater number of unknowns proves to demonstrate the precision of the proposed theory.

모호성의 관점에서 본 마틴 마르지엘라 패션디자인 특성 (Characteristics of Martin Margiela's Fashion Design from the Perspective of Ambiguity)

  • 김순자
    • 한국의상디자인학회지
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    • 제18권2호
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    • pp.191-206
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    • 2016
  • A designer representing an avant guard fashion, Martin Margiela introduces experimental collections that seek ideational and ideal values, breaking away from limits of popular universality or usefulness of fashion. This study seeks to interpret Martin Margiela's design characteristics from the perspective of ambiguity, and thereby examine theoretical basis of meaning interpretation of his ambiguous and innovative design. In poetic meaning ambiguity is verbal nuance which gives room for alternative reaction the same piece of language. By way of study methods, concepts and characteristics of ambiguity were examined based on William Empson's seven types of ambiguity, and characteristics of Martin Margiela's fashion design were analyzed from the perspective of ambiguity. In the study, expression of ambiguity in Martin Margiela's fashion design was categorized into ambiguity of forms, that of meanings, and that of existence. Ambiguity of forms could be found indeterminate form of clothes and flat clothes. Ambiguity of meaning refers to ambiguity arising from the possibility of the meaning that fashion design is going to convey diverse interpretation. Ambiguity of meaning could be found up-cycling vintage clothes, semi-couture, signs of time, unfitting size, and symbolic letter. Ambiguity of existence could be found inanimate dummy, face shrouded with a veil and expression of multiple identity. In Martin Margiela's fashion design ambiguity gives rise to joy of something fresh, amusement felt about what deviates from normality and the possibility of fashion design's endless creations.

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리팩토링을 위한 소프트웨어 메트릭의 베이지안 네트워크 기반 확률적 관리 (Bayesian Network-based Probabilistic Management of Software Metrics for Refactoring)

  • 최승희;이구연
    • 정보과학회 논문지
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    • 제43권12호
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    • pp.1334-1341
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    • 2016
  • 최근 지능형 스마트 디바이스의 눈부신 발전과 사용으로 개발 단계의 소프트웨어 결함 관리의 중요성이 부각되고 있다. 효과적 결함 관리를 위해 소프트웨어 메트릭을 토대로 많은 결함 예측 모델 연구가 수행되고 있지만, 결함 예측 모델 연구 성과가 널리 확산되지는 못하고 있다. 본 논문에서는 결함 존재 유무에 관한 이진적 결함 예측 모델의 제약을 극복할 수 있도록, 베이지안 네트워크 기반 확률적 소프트웨어 메트릭 관리 방법을 제안한다. 제안 모델은 소프트웨어 메트릭을 활용하여 베이지안 네트워크를 구성하고, 이를 토대로 베이지안 추론을 수행하여 리팩토링을 위한 개선점을 식별할 수 있는 모델이다. 코드 리팩토링을 통해 소스 코드가 개선되면 관련 메트릭 측정값 또한 변하게 된다. 제안 모델은 리팩토링을 통한 메트릭의 개선으로 얻을 수 있는 결함 제거 효과를 확률 값으로 제시해준다. 따라서 이진 값 형태의 확정성을 극복할 수 있으며, 불확정적인 확률 값으로 의사결정의 유연성을 확보할 수 있을 것이다.