• Title/Summary/Keyword: Fundamental performance

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A Review on Structural Behavior, Design, and Application of Ultra-High-Performance Fiber-Reinforced Concrete

  • Yoo, Doo-Yeol;Yoon, Young-Soo
    • International Journal of Concrete Structures and Materials
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    • v.10 no.2
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    • pp.125-142
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    • 2016
  • An overall review of the structural behaviors of ultra-high-performance fiber-reinforced concrete (UHPFRC) elements subjected to various loading conditions needs to be conducted to prevent duplicate research and to promote its practical applications. Thus, in this study, the behavior of various UHPFRC structures under different loading conditions, such as flexure, shear, torsion, and high-rate loads (impacts and blasts), were synthetically reviewed. In addition, the bond performance between UHPFRC and reinforcements, which is fundamental information for the structural performance of reinforced concrete structures, was investigated. The most widely used international recommendations for structural design with UHPFRC throughout the world (AFGC-SETRA and JSCE) were specifically introduced in terms of material models and flexural and shear design. Lastly, examples of practical applications of UHPFRC for both architectural and civil structures were examined.

An Exploratory Analysis on Performance Measurement Framework of Organizational Communities of Practice (기업 실행공동체(Communities of Practice) 성과측정체계의 탐색적 분석)

  • Choi, In-Myung;Jeon, Su Hwan;Kim, Young Gul
    • Knowledge Management Research
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    • v.8 no.2
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    • pp.17-30
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    • 2007
  • Firm which implement knowledge management initiatives have found interest in nurturing voluntary knowledge sharing organizations, called communities of practice(CoP). One of the fundamental problems for adopting or implementing CoP is how the firms can measure the performance of CoP. Despite interest in CoP by firms, empirical studies on CoP performance measurement are rare. Thus, this study intends to help the organizations by introducing CoP performance measurement framework based on the previous researches. The framework is further validated by comparing with the eight actual cases. Finally, we propose three propositions regarding the CoP performance measurement.

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Study on the Test Methods and Performance Criterion of High Insulated Door (고기밀.고단열 문의 성능평가 및 기준설정에 관한 연구)

  • Kang, Jae-Sik;Choi, Gyoung-Seok;Kim, Kyoung-Woo;Lee, Seung-Eon
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.618-622
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    • 2009
  • About a Structure is performance insulation include air-tight is fundamental performance for energy-saving. The Apartment house of permission balcony enlarged to increase the requirement of market of high-effective door. Since 2001 years the window and wall of insulation performance stronger frailty than keep up performance insulation that increase influence building energy generated heat loss at door. In study on presentation that high-insulation, air-tight door about experimental method and performance standard.

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Evaluation of Performance on Repair Materials for Creek Concrete Structures (콘크리트 복개구조물용 보수재료의 성능 평가)

  • Lee, Chang-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.1
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    • pp.205-212
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    • 2002
  • The deterioration rate of concrete structures in urban area is accelerated due to rapid urbanization and environmental pollution. Repair materials and methods newly introduced in Korea should be investigated whether they are appropriate for the urban environment in Korea. The creek concrete structures are exposed in severe environmental condition than others. Based on these background in mind, the study is focused on evaluation of performance on repair materials used to rehabilitate creek concrete structures. To evaluate the performance of repair materials, four kinds of repair materials were selected based on polymer emulsion. This experimental study was conducted on fundamental performance such as setting time, compressive strength, bending strength, bonding strength, thermal expansion coefficient, and durability performance such as chloride diffusion, carbonation, chemical attack, and steel corrosion rate. On the basis of this study, the optimal repair material which is proper to the environment condition can be selected and service life of creek concrete structures can be extended. As a result, the life cycle cost can be reduced and the waste of material resources will be cut down.

A Study on the Seller's Right to Cure in the Int'l Sale of Goods (국제물품매매계약(國際物品賣買契約)에서 하자보완권(瑕疵補完權)에 관한 고찰(考察))

  • Ha, Kang-Hun
    • THE INTERNATIONAL COMMERCE & LAW REVIEW
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    • v.12
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    • pp.253-276
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    • 1999
  • CISG articles 34 and 37 clearly allow the seller to cure any nonconformity in documents of sale or performance prior to the date for delivery if it does not cause the buyer unreasonable inconvenience or unreasonable expense. CISG article 48 allows a seller to cure the performance even after the date for delivery if it does not cause the buyer unreasonable delay, unreasonable inconvenience or unreasonable uncertainty of reimbursement by the seller of expenses advanced by the buyer. The wording any failure to perform is broad enough to include a delay. The seller's right to cure relates to all his obligations. The seller may remedy 'any failure to perform his obligations'. This language is broad enough to include a defect in documents. In some cases the fact that the seller is able and willing to remedy the non-conformity of the goods without inconvenience to the buyer, may mean that there would be no fundamental breach unless the seller failed to remedy the non-conformity within an appropriate time. It cannot generally be said what unreasonable inconvenience means. This can only be decided on a case-by-case basis. The seller must bear the costs involved in remedying a failure to perform. The curing of a failure to perform may have influence on the amount of the damage claimed. Insofar as the seller has the right to cure, the buyer is in that case obliged to accept the cure. If he refuses to do so, he can neither avoid the contract nor declare a reduction in price. This rule clearly shows the underlying concept of the CISG, to keep to the contract, if possible. Should the buyer requires delivery of substitute goods and the seller offers repair, it depends on the expense each case. The buyer must receive the request or notice by the seller. The relationship between the seller's right to cure and the buyer's right to avoid the contract is unclear. The buyer's right to avoid the contract should not nullify the seller's right to cure if the offer is reasonable. In addition, whether a breach is fundamental should be decided in the right of the seller's offer to cure.

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Fundamental Evaluation and Hydration Heat Analysis of Low Heat Concrete with Premixed Cement (저발열형 Premixed Cement를 사용한 콘크리트의 기초물성 평가 및 수화열 해석에 관한 연구)

  • Yoon, Ji-Hyun;Jeon, Joong-Kyu;Jeon, Chan-Ki;Kim, Ki-Hyung
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.2 no.1
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    • pp.10-18
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    • 2014
  • This study carried out to evaluate the hydration heat analysis and fundamental characteristics such as air content, slump, compressive strength and dry shrinkage according to concrete with premixed cement, ternary concrete and OPC concrete for using concrete with premixed cement. The results of experiment are founded that concrete with premixed cement have sufficient performances such as workability, compressive strength and dry shrinkage. Also, the results of hydration heat analysis are founded that concrete with premixed cement have more performance than ternary concrete and OPC concrete at a point of view for the quality control such as thermal crack reducing and economic benefit. Therefore, it is desirable that concrete with premixed cement should be used to rise durability performance and convenience of maintenance.

FPGA Implementation of Levenverg-Marquardt Algorithm (LM(Levenberg-Marquardt) 알고리즘의 FPGA 구현)

  • Lee, Myung-Jin;Jung, Yong-Jin
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.11
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    • pp.73-82
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    • 2014
  • The LM algorithm is used in solving the least square problem in a non linear system, and is used in various fields. However, in cases the applied field's target functionis complicated and high-dimensional, it takes a lot of time solving the inner matrix and vector operations. In such cases, the LM algorithm is unsuitable in embedded environment and requires a hardware accelerator. In this paper, we implemented the LM algorithm in hardware. In the implementation, we used pipeline stages to divide the target function operation, and reduced the period of data input of the matrix and vector operations in order to accelerate the speed. To measure the performance of the implemented hardware, we applied the refining fundamental matrix(RFM), which is a part of 3D reconstruction application. As a result, the implemented system showed similar performance compared to software, and the execution speed increased in a product of 74.3.

Distance Relaying Algorithm Using a DFT-based Modified Phasor Estimation Method (DFT 기반의 개선된 페이저 연산 기법을 적용한 거리계전 알고리즘)

  • Lee, Dong-Gyu;Kang, Sang-Hee
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.8
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    • pp.1360-1365
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    • 2010
  • In this paper, we propose a distance relaying algorithm using a Discrete Fourier Transform (DFT)-based modified phasor estimation method to eliminate the adverse influence of exponentially decaying DC offsets. Most distance relays are based on estimating phasors of the voltage and current signals. A DFT is generally used to calculate the phasor of the fundamental frequency component in digital protective relays. However, the output of the DFT contains an error due to exponentially decaying DC offsets. For this reason, distance relays have a tendency to over-reach or under-reach in the presence of DC offset components in a fault current. Therefore, the decaying DC components should be taken into consideration when calculating the phasor of the fundamental frequency component of a relaying signal. The error due to DC offsets in a DFT is calculated and eliminated using the outputs of an even-sample-set DFT and an odd-sample-set DFT, so that the phasor of the fundamental component can be accurately estimated. The performance of the proposed algorithm is evaluated for a-phase to ground faults on a 345 kV, 50 km, simple overhead transmission line. The Electromagnetic Transient Program (EMTP) is used to generate fault signals. The evaluation results indicate that adopting the proposed algorithm in distance relays can effectively suppress the adverse influence of DC offsets.

Performance Improvement of Single-phase PLL Control using State Observer (상태관측기를 이용한 단상 PLL제어의 성능 개선)

  • Hwang, Hee-Hun;Choi, Jong-Woo
    • The Transactions of the Korean Institute of Power Electronics
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    • v.14 no.2
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    • pp.96-104
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    • 2009
  • This paper proposes a single-phase Phase-locked loop (PLL) of the virtual two phase generator using full-order state observer, which is essential to find phase and frequency of the single-phase source. The conventional methods cannot remove the low-order harmonics included in source voltage, which influencesto whole PLL control system. The proposed algorithm separates fundamental wave from harmonics, and removes harmonics effectively. Therefore it generates only the fundamental wave. As it controls virtual voltage and input voltage together, it decreases steady-state error. From simulation and experimental results, the generated frequency by the proposed PLL which it plans, converges to the actual value, and the steady-state error is much reduced under given harmonic voltages. It is also confirmed that the proposed algorithm removed harmonics effectively and it generates only the fundamental wave.