• Title, Summary, Keyword: performance based

Search Result 39,947, Processing Time 0.122 seconds

Composite Behavior and Shear Strength of DH-Beams with Steel Deck Plates (무해체 데크플레이트 철판을 사용한 DH-beam의 합성거동과 전단강도)

  • Moon, Jeong-Ho;Oh, Young-Hun
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.20 no.3
    • /
    • pp.1-9
    • /
    • 2016
  • The purpose of this study is to examine the shear strength and structural performance of DH-Beams. The DH-Beam construction method uses thin steel plates as form-works and structural elements. Steel plates and rebars for DH-Beams were prefabricated at factory and then erected before casting concrete at construction sites. In this study, the contribution of steel plates to the shear strength of DH-Beam was evaluated since the plates were expected to work as reinforcements. Five test specimens were made for experimental and analytical studies. They consisted of two DH-Beams for the positive loading test and two DH-Beams for the negative loading test and a RC beam for the comparison purpose. Test results on DH-Beams were compared with design equations and the RC beam test result. It was proven that DH-Beams demonstrated the good shear behavior showing sufficient strengths and deformation capacities. Nonlinear analyses with test specimens were also used to evaluate the contribution of DH plates to strengths. Analytical models included various cases such as beams with lateral plates only or beams without any plates. These analyses also showed that steel plates can contribute to the enhancement of shear strength of DH-Beams. Based on experimental and analytical studies, it was concluded that steel plates of DH-Beams can be used as good shear reinforcements.

Kalman Filter-based Data Recovery in Wireless Smart Sensor Network for Infrastructure Monitoring (구조물 모니터링을 위한 무선 스마트 센서 네트워크의 칼만 필터 기반 데이터 복구)

  • Kim, Eun-Jin;Park, Jong-Woong;Sim, Sung-Han
    • Journal of the Korea institute for structural maintenance and inspection
    • /
    • v.20 no.3
    • /
    • pp.42-48
    • /
    • 2016
  • Extensive research effort has been made during the last decade to utilize wireless smart sensors for evaluating and monitoring structural integrity of civil engineering structures. The wireless smart sensor commonly has sensing and embedded computation capabilities as well as wireless communication that provide strong potential to overcome shortcomings of traditional wired sensor systems such as high equipment and installation cost. However, sensor malfunctioning particularly in case of long-term monitoring and unreliable wireless communication in harsh environment are the critical issues that should be properly tackled for a wider adoption of wireless smart sensors in practice. This study presents a wireless smart sensor network(WSSN) that can estimate unmeasured responses for the purpose of data recovery at unresponsive sensor nodes. A software program that runs on WSSN is developed to estimate the unmeasured responses from the measured using the Kalman filter. The performance of the developed network software is experimentally verified by estimating unmeasured acceleration responses using a simply-supported beam.

Cyclic Simple Shear Test Based Design Liquefaction Resistance Curve of Granular Soil (반복단순전단시험에 기반한 조립토의 설계 액상화 저항 곡선 개발)

  • Saeed-ullah, Jan Mandokhail;Park, Duhee;Kim, Hansup;Park, Ki-Chun
    • Journal of the Korean Geotechnical Society
    • /
    • v.32 no.6
    • /
    • pp.49-59
    • /
    • 2016
  • We develop liquefaction resistance curves, which represent the correlation between cyclic resistance ratio (CRR) and number of cycles (N) to estimate the build-up of residual excess pore pressure from simple shear tests performed for this study and also from published literature. The liquefaction curve is calculated from two models. The comparisons show that one of the models is not reliable because it underestimates CRR. The scatter of the data is shown to be significantly reduced when CRR is normalized to the resistance ratio at N = 15 ($CRR_{N=15}$). Use of the normalization is particularly useful because CRR can be easily estimated from field tests. From normalization, we propose mean, upper, and lower curves. The corresponding design equation and its parameters are also proposed. We believe that the proposed curves can be used for effective stress site response analyses and evaluation of the seismic performance of port structures.

Effects of Water Temperature and Feeding Rate on Growth and Body Composition of Grower Olive Flounder Paralichthys olivaceus (사육 수온 및 사료 공급율이 넙치의 성장 및 체조성에 미치는 영향)

  • KIM, Kyoung-Duck;KIM, Kang-Woong;LEE, Bong-Joo;HAN, Hyon-Sob
    • Journal of Fisheries and Marine Sciences Education
    • /
    • v.28 no.3
    • /
    • pp.611-618
    • /
    • 2016
  • A $3{\times}2$ factorial experiment was conducted to investigate effects of water temperature and feeding rate on growth and body composition of olive flounder. Triplicate groups of fish (initial body weight of 118 g) fed a extruded pellet (55% protein and 4708 cal/g) to satiation and at restricted feeding rates of 0.25 and 0.4% body weight per day (BW/d) at the different water temperatures (13 and $18^{\circ}C$) for 9 weeks. Weight gain increased significantly with increase in feeding rates at each temperature. Weight gain of fish fed to satiation was significantly higher at 18 than $13^{\circ}C$, whereas, that of fish fed at 0.25 and 0.4% BW/d were significantly or slightly lower at 18 than $13^{\circ}C$. Feed efficiency and protein efficiency ratio of fish fed to satiation were not significantly different between 13 and $18^{\circ}C$, but those of fish fed at 0.25 and 0.4% BW/d were significantly higher at 13 than $18^{\circ}C$. The major finding of this study is that satiation feeding is efficient for optimal growth and feed efficiency of grower oliver flounder (116-164 g) in suboptimal water temperatures. The maintenance feeding ration which is zero growth performance, were 0.30 and 0.41% BW/day at 13 and $18^{\circ}C$, respectively. In the restricted feeding regime, compromised growth of fish were worsen in higher water temperature ($18^{\circ}C$ vs. $13^{\circ}C$). It might be related to high metabolic rate of fish that spend more energy for maintenance metabolism. Based on these results, we suggest that a satiation feeding regime is recommended for a productive growth of grower olive flounder in the suboptimal temperature.

Treatment Efficiency Evaluation of Integrated Two-Phase Pilot-Scale Anaerobic Digestion Using Food Waste Leachate (Pilot Scale 일체형 2상 혐기성소화에서의 음폐수 처리효율 평가)

  • Song, Hancheul;Kim, Dongwook
    • Journal of the Korea Organic Resources Recycling Association
    • /
    • v.24 no.2
    • /
    • pp.51-58
    • /
    • 2016
  • In the Integrated Two-Phase Anaerobic Digestion (ITPAD) process, acid and methane fermentation take place in one reactor, which has advantages to cope with organic load variation and reduce foot-print required, compensating disadvantages of Conventional Separated Two-Phase Anaerobic Digestion (CSTPAD). In the present work, organic matter degradation efficiency and biogas generation amount and other performance parameters of the ITPAD fed with food waste leachate were analyzed. In addition, feasibility study on the ITPAD method was performed by comparing its digestion efficiency with that of the CSTPAD. Organic matter alteration and biogas generation of the integrated method were examined for approximately 130 days based on the 5ton/day scaled pilot plant. Experiment results revealed that organic matter removal rate was 80% for mean food waste leachate input amount of $4.1m^3/day$. The biogas generation rate was $63.0m^3$ per ton of food waste leachate input, corresponding to the input VS amount of $0.724m^3/kg-VS_{added}$, and methane content of generated biogas was approximately 61.3%. The ITPAD has a comparable or higher organic matter removal efficiency compared to the conventional separated two-phase anaerobic digestion method. Consequently, the ITPAD method has a great need to commercialize a food waste leachate treatment technology against highly concentrated organic waste leachate.

Investigation of the Bond and Deformation Characteristics between an Asphalt layer and a Concrete Slab used as the Trackbed Foundation of an Embedded Rail System for Wireless Trams (무가선 트램용 매립형궤도 아스팔트 포장층의 부착특성 및 변형발생특성 분석)

  • Cho, Hojin;Kang, Yunsuk;Lee, Suhyung;Park, Jeabeom;Lim, Yujin
    • Journal of the Korean Society for Railway
    • /
    • v.19 no.2
    • /
    • pp.224-233
    • /
    • 2016
  • Embedded Railway Systems (ERS) will be adapted for wireless trams and will be constructed along city roadways. An asphalt layer should be overlaid on top of the concrete slab used as the trackbed structure in order to ensure smoothness and surface levels equal to those of existing road pavement in downtown city areas. However, the characteristics of an asphalt layer when used as overlay pavement for an ERS are complicated and the behavior of this material is not yet well defined and understood. Therefore, in this study, laboratory shear and tensile bond strength tests were conducted to investigate the bonding behavior of an asphalt layer in a multilayered trackbed section of an ERS. For the laboratory tests, a waterproof coating material was selected as a bonding material between the asphalt overlay and a concrete specimen. Valuable design parameters could be obtained based on the tensile and shear bond strength test results, providing information about the serviceability and durability of the overlaid pavements to be constructed alongside the ERS for wireless trams. In addition, a deformation analysis to assess the tensile strain generated due to truck axle loads at the interface between the asphalt layer and the concrete slab was conducted to verify the stability and performance of the asphalt layer.

A Study of the Proper Sizing of a Subway Station Waiting Area (도시철도 대기공간의 적정규모 산정에 관한 연구)

  • Kim, Jonghwang;Baek, Sungjoon;Nam, Doohee
    • Journal of the Korean Society for Railway
    • /
    • v.19 no.2
    • /
    • pp.262-269
    • /
    • 2016
  • Subway station scales are determined by peak predictions. In this study, the purpose behind the installation of a subway is public transportation convenience and public interest, but economic validity is also important. By proving that the scale of the station is excessive with regard to the target station size for Seoul subway Line 5-8, a reasonable plan. can be sought. According to station installation standards, the area of the station under investigation here is out of the service levels by six stages (A~F), and it must be four or more levels (D). The Actual level for the B level is a two-step design. The Actual ratio for over- Peak predictions is only 17.8% on average. The results of measurements of the excess area and determination of the excessive costs were analyzed by subdividing the area and by calculating it based on the B level, finding that it is possible to provide benefits for customers only in the current design, with an area ratio of 16.3%. Given the weight, it was estimated that current conditions can meet the needs of only 18.6% of the current area. Simplifying the scale calculation method of the station, it is convenient, safe, and advantageous to move citizens only if the scale can be streamlined. Then, with a reduced initial investment, maintenance costs during the operation can be reduced.

Evaluation of Fracture Behavior of Adhesive Layer in Fiber Metal Laminates using Cohesive Zone Models (응집영역모델을 이용한 섬유금속적층판 접착층의 모드 I, II 파괴 거동 물성평가)

  • Lee, Byoung-Eon;Park, Eu-Tteum;Ko, Dae-Cheol;Kang, Beom-Soo;Song, Woo-Jin
    • Composites Research
    • /
    • v.29 no.2
    • /
    • pp.45-52
    • /
    • 2016
  • An understanding of the failure mechanisms of the adhesive layer is decisive in interpreting the performance of a particular adhesive joint because the delamination is one of the most common failure modes of the laminated composites such as the fiber metal laminates. The interface between different materials, which is the case between the metal and the composite layers in this study, can be loaded through a combination of fracture modes. All loads can be decomposed into peel stresses, perpendicular to the interface, and two in-plane shear stresses, leading to three basic fracture mode I, II and III. To determine the load causing the delamination growth, the energy release rate should be identified in corresponding criterion involving the critical energy release rate ($G_C$) of the material. The critical energy release rate based on these three modes will be $G_{IC}$, $G_{IIC}$ and $G_{IIIC}$. In this study, to evaluate the fracture behaviors in the fracture mode I and II of the adhesive layer in fiber metal laminates, the double cantilever beam and the end-notched flexure tests were performed using the reference adhesive joints. Furthermore, it is confirmed that the experimental results of the adhesive fracture toughness can be applied by the comparison with the finite element analysis using cohesive zone model.

A Distributed SPARQL Query Processing Scheme Considering Data Locality and Query Execution Path (데이터 지역성 및 질의 수행 경로를 고려한 분산 SPARQL 질의 처리 기법)

  • Kim, Byounghoon;Kim, Daeyun;Ko, Geonsik;Noh, Yeonwoo;Lim, Jongtae;Bok, kyoungsoo;Lee, Byoungyup;Yoo, Jaesoo
    • KIISE Transactions on Computing Practices
    • /
    • v.23 no.5
    • /
    • pp.275-283
    • /
    • 2017
  • A large amount of RDF data has been generated along with the increase of semantic web services. Various distributed storage and query processing schemes have been studied to efficiently use the massive amounts of RDF data. In this paper, we propose a distributed SPARQL query processing scheme that considers the data locality and query execution path of large RDF data. The proposed scheme considers the data locality and query execution path in order to reduce join and communication costs. In a distributed environment, when processing a SPARQL query, it is divided into several sub-queries according to the conditions of the WHERE clause by considering the data locality. The proposed scheme reduces data communication costs by grouping and processing the sub-queries through the index based on associated nodes. In addition, in order to reduce unnecessary joins and latency when processing the query, it creates an efficient query execution path considering data parsing cost, the amount of each node's data communication, and latency. It is shown through various performance evaluations that the proposed scheme outperforms the existing scheme.

Influence of Application Method on Shear Bond Strength and Microleakage of Newly Developed 8th Generation Adhesive in Primary Teeth (새로 개발된 8세대 접착제의 적용 방법에 따른 유치에서의 전단결합강도와 미세누출)

  • Ryu, Wonjeong;Park, Howon;Lee, Juhyun;Seo, Hyunwoo
    • THE JOURNAL OF THE KOREAN ACADEMY OF PEDTATRIC DENTISTRY
    • /
    • v.46 no.2
    • /
    • pp.165-172
    • /
    • 2019
  • The purpose of this study was to evaluate the effect of application time and phosphoric acid etching of 8th generation adhesives containing functional monomer on adhesive performance in primary teeth. 80 extracted non-carious human primary teeth were selected and divided into 8 groups based on 3 factors: (1) adhesive: G-Premio bond and Single bond universal; (2) application time: shortened time and manufacture's instruction; (3) acid etching mode: self-etching and total-etching. Shear bond strength was measured using a universal testing machine, and fractured surface were observed under scanning electron microscope. Microleakage was evaluated by dye penetration depth. G-Premio bond were not significant different in shear bond strength and microleakage depending on application time of adhesive and acid etching mode. In Single bond universal, shear bond strength of short application time was significantly lower than that of long adhesive application time (p = 0.014). Clinically applicable shear bond strength values (> 17 MPa) were identified in all groups. These results suggested that G-Premio bond be used clinically for a short application time without phosphoric acid etching.