• KNOM Review
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• 제24권1호
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• pp.29-37
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• 2021

인터넷이 확산되면서 웹을 통해 사용자는 쉽게 다양한 서비스를 제공받고 정보를 교환할 수 있게 되었다. 웹 시스템을 구축할 때 다양한 요구 사항들이 존재하며, 사용자 목적에 적합한 언어 또는 플랫폼을 사용하여 웹 시스템을 구축해야 한다. 잔류물질정보란 식품 등에 첨가되는 의약품, 농약 들에 대한 정보들을 의미하며 그 중 잔류허용기준은 기업과 농민들이 생산하는 식품 내 잔류물질수치를 측정하여 해당 수치가 국내 혹은 국제 기준을 만족하는지 가늠하는 척도로 사용되고 있다. 현재 식품의약품안전처에서는 식품과 농약 및 동물용의약품을 포함한 식품첨가물에 대한 잔류허용기준을 문서 형태로 제공하고 있으며 이는 웹 시스템 구축을 통해 사용자가 원활하고 편리하게 서비스되어야 한다. 또한, 사용자 접근성을 포함하여 확장성, 호환성 등 다양한 요구 사항을 만족해야 한다. 본 논문은 사용자가 더 편리하게 접근할 수 있고 원활한 잔류물질정보를 제공받을 수 있는 React 기반 잔류물질정보 웹 시스템을 제안한다. 우리는 정보 제공에 있어 중요한 3가지 기능에 대한 속도를 측정하여 기존 잔류물질정보 웹 시스템과 비교하였으며 확장성, 호환성, 접근성 등 7가지 필수 요구 사항에 대하여 정성적으로 평가하였다.

• KNOM Review
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• 제23권2호
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• pp.11-17
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• 2020

현재 잔류물질정보를 제공하는 웹 페이지에서는 농약 및 동물용의약품의 식품 내 잔류허용기준 정보를 제공하고 있다. 잔류물질이란 농약 혹은 동물용의약품을 수천 배 희석하여 사용 후 농산물 또는 축, 수산물에 남아 있게 되는 극미량의 농약 혹은 동물용의약품을 뜻한다. 하지만 농약과 동물용의약품에 대한 정보의 누락, 웹 페이지 오류 등 정보 제공이 원활하게 이루어지지 않고 있기 때문에 사용자들이 불편을 겪고 있다. 또한 관리자는 잔류허용 기준 및 분석법 등 정보들을 수동으로 입력해야하는 불편함이 있다. 이에 본 논문에서는 농약 및 동물용의약품에 대한 잔류물질기준과 약품의 특성 등 정보들의 변화이력을 효율적으로 관리하고 업데이트 할 수 있는 시스템을 제안한다.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1674-1681
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• 2003

Photoelastic experiment has two significant problems. The first problem is manufacturing a model specimen for complicated shapes of structures. The second problem is residual stress contained in the photoelastic model material. In this paper, the stress optic law that can be effectively used on photoelastic model materials with residual stress is developed. By using the stress optic law as developed in this research, we can obtain good results in photoelastic experiments using model material in which residual stress is contained. It is assured that the stress optic law developed in this research is useful. Therefore, it is suggested that the stress optic law considering residual stress can be applied to the photoelastic experiment for the stress analysis of the composite materials or bi-materials in which the residual stress is easily contained.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1347-1356
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• 2024

Measuring the residual stress in the components in nuclear power plants is crucial to their safety evaluation. The instrumented indentation technique is a minimally invasive approach that can be conveniently used to determine the residual stress in structural materials in service. Because the indentation behavior of a structure with residual stresses is closely related to the elastic-plastic behavior of the indented material, an accurate understanding of the elastic-plastic behavior of the material is essential for evaluation of the residual stresses in the structures. However, due to the analytical problems associated with solving the elastic-plastic behavior, empirical equations with limited applicability have been used. In the present study, the impact of the non-equibiaxial residual stress state on indentation behavior was investigated using finite element analysis. In addition, a new nonequibiaxial residual-stress prediction methodology is proposed using a convolutional neural network, and the performance was validated. A more accurate residual-stress measurement will be possible by applying the proposed residual-stress prediction methodology in the future.

• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.757-761
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• 2002

When a layer of cylindrical composite component containing an axisymmetric residual stress state is removed from the inner or outer surface, the dimension of the remaining material changes to balance internal forces. Therefore, in order to machine cylindrical composite components within tolerances, it is important to know dimensional changes caused by residual stress redistribution in the body. In this study, analytical solutions for dimensional changes and the redistribution of residual stresses due to the layer removal from a residually stressed cylindrically orthotropic cylinder were developed. The cylinder was assumed to have axisymmetric radial, tangential and axial residual stresses. The result of this study is useful in cases where the initial residual stress distribution in the component has been measured by a non-destructive technique such as neutron diffraction with no information on the effect of layer removal operation on the dimensional changes.

• 한국공간구조학회논문집
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• 제18권1호
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• pp.127-134
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• 2018

This study suggests the tangent modulus $E_t$ associated with partially yielded section of steel member under axially compressed. The provisions for column strength does not provide a information about failure mode of structural system. So, designers can not evaluate that a failure comes from member buckling or material yielding. The material of the axially compressed column under inelastic behavior reaches yielding point before the axial force renders the column bent. If axial members yields not by buckling effect but gradually yielding effect of material, the design code should accept related tangent modulus Et which is based on gradual yielding effect of material. This study provides the new effective tangent modulus $E_t$ derived in the case that residual stress is 30 percent and 50 percent of yielding stress respectively. The study considers idealized I section of steel which ignores web and general I section of steel with web respectively and makes conclude that tangent modulus $E_t$ with idealized I section of steel is rational.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.294-295
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• 2006

Varistor fabricated with ZnO nano-powder was studied about the characteristic of energy capability in this paper. ZnO nano-powder varistor were sintered in air at $1050\;^{\circ}C$. The electrical properties and residual voltage of ZnO nano-powder varistor were obtained. Our ZnO nano-powder varistor has about 3 times of electric field at varistor voltage as compared with commercial ZnO varistor fabricated with micro-powder. In the current impulse withstand test, our nano varistor has had better performance than micro varistor. To analysis energy capability take infrared images for pyrexia distribution of each varistor. ZnO Nano-powder varistor has shown much quick response property because of increasing effective cross-section.

• Journal of Chest Surgery
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• 제35권8호
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• pp.580-583
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• 2002

배경: 선천성 심장병 환자들의 교정 수술 후 정확한 형태학적 혹은 혈역학적변화를 아는 것이 술 후 추가적으로 내과적 혹은 외과적인 치료가 필요로 하는가를 결성하는데 매우 중요하다. 심실중격결손 봉합술 후 잔류단락의 발생 빈도와 소량의 포편 주위 단락의 변화를 조사하였다. 대상 및 방법: 1995년 3월부터 1999년 12월까지 영남대학교의료원 흉부외과에서 영아기에 단순 심실중격결손으로 포편봉합술을 시행한 43명의 환자들을 대상으로 수술 후 심초음파를 시행하여 잔류단락 유무를 조사하였다. 결과: 전체 43례의 환자 중 수술 직후 잔류단락이 관찰된 환자는 11례로 26%에서 잔류단락이 발견되었으나 혈역학적으로 유의한 단락으로 재수술을 시행한 경우는 없었다. 단락의 발생빈도는 심실중격결손의 형태와 봉합을 위해 사용한 포편의 종류와는 무관하였다. 잔류단락이 발견된 환자 중 9명에서 단락의 소실을 확인할 수 있었으며 2례는 추적관찰에서 탈락하였다. 단락이 소실된 9명의 환자들의 단락이 마지막 확인된 기간은 평균 $4.2{\pm}3.6$개월 이었다. 결론: 수술 직후 포편 주위의 잔류단락은 종종 발견될 수 있으며 혈역학적으로 유의하지 않은 잔류단락은 대부분 6개월 이내에 자연 소실되었다.

• The Journal of Asian Finance, Economics and Business
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• 제7권3호
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• pp.137-148
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• 2020

The purpose of this study is to investigate factors influencing risk assessment of material misstatement in Vietnamese enterprises listed on stock market. Expert interview method was conducted to discover the scales for three variables including information system, trademark, and risk assessment of material misstatement. Survey method was used to examine the impacts of eight factors on risk assessment of material misstatement. Data is collected from 317 auditors who have excellent experience in auditing financial statements of companies listed on stock market. Then, data is processed by descriptive statistics, reliability analysis, factor extracted analysis, correlative regression analysis, and analysis variance of residual change. The research findings showed that business characteristic, stakeholder pressure, and economic environment have positive relationships with risk assessment of material misstatement. Three variables including operation control and monitor, control environment, and information system negatively affect to risk assessment. Specially, business characteristic and information system, which are elements in internal control, have strongest impact on risk assessment. One the other hand, assessment of internal control plays an important role not only in the audit plan stage but also throughout the stages of the audit implementation and ending. Therefore, appropriate solutions are proposed to carry out all audit stages.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.180-184
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• 2017

In this study, we examine the electrical properties of diketopyrrolopyrrole (DPP) containing polymer semiconductors that have been reported to show high performance with ambipolar characteristics. We prepared three different DPP based polymer semiconductors (PDPPTPT, PDPP3T, and PDPP2T-TT) and fabricated organic thin film transistors (OTFTs) with ambipolar polymer semiconductors as an active layer. All three DPP polymers showed only p-type properties at initial measurements. However, after annealing in vacuum oven for 24 hours, it was found that the DPP based polymers have both p-type and n-type properties. It is speculated that the residual impurities supposedly regarded as a strong electron trap source were eliminated during the vacuum process.