• Title/Summary/Keyword: External

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Present and Future of Risk Management of Construction Practice in Asia

  • Watanabe, Tsunemi
    • International conference on construction engineering and project management
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    • 2015.10a
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    • pp.4-5
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    • 2015
  • Owning to rapid infrastructure development, Asia is experiencing dramatic economic growth. There are not a few cases in which, however, economic growth is achieved by increasing the external diseconomy. Pursuit of sustainable development is one of the most important issues for mankind. Under the post-industrial capitalism society, however, there seems a big risk of increase in the external diseconomy worldwide. The objectives of this manuscript are to discuss importance of risk management of construction practice in present and future. Regarding the latter, a particular attempt is made to discuss how project risk communication should be done to reduce the external diseconomy. Presently, one of the important issues in implementation of infrastructure projects is practice of risk management to properly manage time, cost, quality, and safety: mainly maximization of internal economy. Multi-party risk and uncertainty management process (MRUMP) is one of tolls to assist it. The idea on MRUMP can be used to reduce the external diseconomy through identifying, sharing, and tuning people's rhythms.

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Promotion or Prevention? The Moderating Effect of Embedded External Reviews on Consumer Evaluations

  • Ziqiong Zhang;Le Wang;Shuchen Qiao;Zili Zhang
    • Journal of Smart Tourism
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    • v.3 no.3
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    • pp.5-15
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    • 2023
  • Given the increasing information overload among users of online review websites, understanding the manner in which cognitive costs are reduced and efficient information is made reliable has become increasingly important. This study targets a unique consumer review design and explores how reviews from an external peer-to-peer site embedded in an online travel agency (OTA) website influence subsequent evaluation behaviors. The empirical results indicate that (1) embedded external reviews with a high average valence tend to strengthen the influence of the positive evaluation ratio while diminishing the effect of the review volume, and (2) embedded external reviews with a large variance strengthen the positive effect of the review volume while weakening the effect of the positive evaluation ratio on subsequent positive evaluations. The findings provide practical insights for consumers and online platforms.

A Study on Long-Term Cycling Performance by External Pressure Change for Pouch-Type Lithium Metal Batteries

  • Seong-Ju Sim;Bong-Soo Jin;Jun-Ho Park;Hyun-Soo Kim
    • Journal of Electrochemical Science and Technology
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    • v.15 no.2
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    • pp.314-320
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    • 2024
  • Lithium dendrite formation is one of the most significant problems with lithium metal batteries. The lithium dendrite reduces the lithium metal batteries' cycling life and safety. To apply consistent external pressure to a lithium metal pouch cell, we design a press jig in this study. External pressure creates dense lithium morphology by preventing lithium dendrite formation. After 300 cycles at 1 C, the cells with the external pressure perform far better than the cells without it, with a cycling retention of 97.8%. The formation of stable lithium metal is made possible by external pressure, which also enhances safety and cyclability.

Characteristics of an External-Cavity Semiconductor Laser with a Fabry-Perrot Etalon inside the External reflector (외부공진기 내에 훼브리 페롯 에탈론이 삽입된 반도체 레이저의 특성)

  • 이명우;서동선
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.18 no.6
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    • pp.793-801
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    • 1993
  • We show theoretically that the performance characteristics of an external cavity semiconductor laser, such as frequency locking and frequency noise reduction, can be greatly improved by just inserting a high finesse Fabry-Perrot(F-P) etalon inside the external reflector. For example, when the F-P etalon of finesse 30 and optical thickness 1.5cm is inserted inside the external cavity of length 3.0cm, the frequency locking accuracy and the linewidth reduction ration are increased up to 7.6 times and 86 times respectively compared with the conventional external-cavity laser under the same operation condition.

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Analysis of External Fibrillation of Fiber by Confocal Reflection Microscopy (공초점반사현미경법을 이용한 섬유의 외부소섬유화 분석)

  • Kwon, Ohkyung
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.46 no.2
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    • pp.35-45
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    • 2014
  • Confocal Reflection Microscopy (CRM) was applied to investigate external fibrillation of different types of fibers such as Kajaani reference fiber, Whatman filter fiber, thermomechanical pulp (TMP), and recycled TMP fiber. It was confirmed that the CRM images are created from surface structures of the fiber cell wall. Confocal Laser Scanning Microscopy (CLSM) captured overall shape of the fiber, but minute details of the surface of the fiber were missed. CRM captured the minute details of the fiber surface. From the CRM and CLSM images, it was observed that the CRM images mainly appeared on the fiber surfaces. External fibrillation of the fiber occurs at the fiber surface, not inside the cell wall. Thus, it was concluded that investigation on the external fibrillation of the fiber was possible by utilizing CRM images. A direct qualtitative and quantitative method for analysis of external fibrillation of fiber was demonstrated by utilizing surface area to volume ratio, volume fraction, and roughness calculated from 3-dimensional images reconstructed from stacks of CRM images from the different fibers.

The Heat Transfer Analysis of 1.2[kW] BLDC Motor on the Condition of the External Flow (외부 유동을 고려한 1.2[kW] BLDC 모터의 열 전달 해석)

  • Hwang, Ha-Young;Chung, Tai-Uk;Lee, Dong-Yeon;Hwang, Pyung;Shim, Jae-Sool
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.2
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    • pp.27-33
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    • 2012
  • In this paper, we researched the heat transfer analysis of 1.2[kW] BLDC motor on the condition of the external flow. The BLDC motor is fallen under influence of some heat generated by rotationg motor speed and it changes the life and confidence of motor. The heat makes to reduce the life of insulation and the magnetization. So motor can't make own performance. Therefore we calculated the losses about number of revolutions of motor. And then, we analyzed the heat transfer of BLDC motor by using the results when a fan attached to motor makes the external flow or not. The results showed that the temperature of motor increased constant values irrespective of external air temperature. The temperature of motor decreased very lower values than prior researches when the fan makes the external flow. In this method we can analyze the performance, losses and heat transfer of motor applied in the many industries.

Wind pressure characteristics of a low-rise building with various openings on a roof corner

  • Wang, Yunjie;Li, Q.S.
    • Wind and Structures
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    • v.21 no.1
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    • pp.1-23
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    • 2015
  • Wind tunnel testing of a low-rise building with openings (holes) of different sizes and shapes on a roof corner is conducted to measure the internal and external pressures from the building model. Detailed analysis of the testing data is carried out to investigate the characteristics of the internal and external pressures of the building with different openings' configurations. Superimposition of the internal and external pressures makes the emergence of positive net pressures on the roof. The internal pressures demonstrate an overall uniform distribution. The probability density function (PDF) of the internal pressures is close to the Gaussian distribution. Compared with the PDF of the external pressures, the non-Gaussian characteristics of the net pressures weakened. The internal pressures exhibit strong correlation in frequency domain. There appear two humps in the spectra of the internal pressures, which correspond to the Helmholtz frequency and vortex shedding frequency, respectively. But, the peak for the vortex shedding frequency is offset for the net pressures. Furthermore, the internal pressure characteristics indirectly reflect that the length of the front edge enhances the development of the conical vortices.The objective of this study aims to further understanding of the characteristics of internal, external and net pressures for low-rise buildings in an effort to reduce wind damages to residential buildings.

Prediction of Prestressing Steel Stress at Ultimate State of Prestressed Concrete Members with External Unbonded Tendons (외부 프리스트레스트 콘크리트 부재의 극한상태에서의 강선응력예측식 제안)

  • 오병환;유성원
    • Journal of the Korea Concrete Institute
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    • v.11 no.6
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    • pp.13-24
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    • 1999
  • The external, unbonded prestressed concrete(PSC) members exhibit very different structural behavior from that of internal bonded PSC members because of eccentricity change and slip occurrence during loading process. The purpose of the present study is to propose the ultimate failure stresses of prestressing (PS) steels for those external unbonded PSC members. To this end, a comprehensive analysis has been made using the nonlinear finite element analysis program developed recently for external unbonded PSC members by authors. A series of major influencing variables have been included in the analysis. It was found that the span-depth ratio, neutral axis depth-effective depth ratio, load geometry, amount of ordinary steel, and prestressing steel ration have great influence for the ultimate failue stress of PS steel is preposed and is compared with experimental dat as well as existing formulas for internal unbonded members. The Comparison indicates that the proposed equation agrees relatively well with experimental data and that existing formulas including ACI and AASHTO equations show some discrepancies from experimental ones. The present study allows more realistic analysis and design of prestressed concrete structures with external unbonded tendons.

A Study of the Method for External Noise Shielding using the GIS UHF Sensor Module Applied to the Partial Discharge Signal Sensitivity and Method of Frequency Transforming in the Internal GIS (GIS내부의 부분방전신호 감도개선 및 주파수변환기법에 의한 GIS UHF Sensor 모듈의 외부노이즈차폐기법에 관한 연구)

  • Lee, Seung-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.4
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    • pp.728-732
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    • 2010
  • GIS(Gas insulated switching gear) is power equipment with excellent dielectric strength and is economy merit in high confidence and stability. Recently, because equipment of GIS was occurring problem of confidence used for a long time, partial discharge on-line diagnosis systems have been importantly recognized. Partial discharge (PD) detection is an effective means for monitoring and evaluation of dielectric condition of gas insulated system (GIS). The ultra-high-frequency (UHF) PD detection technique can detect and locate the PD sources inside GIS by detecting electromagnetic wave emitted from PD source. Therefore, real-time diagnostic system using UHF detection method has been developed for this application is being expanded gradually. However, the signal of partial discharge occurring in SF6 gas is very weak and susceptible to external noises which mainly consist of PD in air. Thus, it is important to distinguish the PD in SF6 gas more sensitively from the external noises. Unfortunately, these external noise signals and the partial discharge signals have very similar characteristics. Therefore, to solve this problem, we need the signal processing method for distinguish partial discharge signals with external noise signals for improvement of SNR(signal to noise ratio) and sensitivity. In this paper, we proposed internal signal processing method for removing external noise signals with built-in pre.amplifier and frequency conversion circuit.

A Study on External Light Noise Reduction Using Stereo Vision System in Image Monitoring System (스테레오비전시스템을 이용한 실내 영상감시시스템의 외란광 간섭 경감에 관한 연구)

  • Kim, Soo-In
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.9
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    • pp.83-90
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    • 2009
  • In this paper, a method for reduction of error ratio by external light noise is proposed, which separates error moving component caused by external light noise from moving component of an object, using depth information of stereo image. If measured depth information change of extracted moving component is insignificant, the moving component is considered as external light noise, which concludes that there is no moving object. Experimental results assert the usefulness of the proposed method which makes error ratios by external light noise and by false image as shadow diminish.