• Title/Summary/Keyword: anchors

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Analytical Parametric Study on Pullout Capacity of Embedded Suction Anchors (매입된 석션앵커의 인발력에 대한 분석적 매개변수의 연구)

  • Boonyong, Sorrawas;Park, Ki Chul;Kim, In Chul
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.3
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    • pp.182-189
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    • 2015
  • The Embedded Suction Anchor (ESA) is a type of permanent offshore foundation that is installed by a suction pile. To increase the loading capacity against pullout, three wings (vertical flanges) are attached along the circumference at 120 degrees apart. Analytical parametric study using the proposed analytical solution method has been conducted to identify the effects of several parameters that are thought to influence the behavior of ESAs. The analysis results show that the pullout capacity increases as the anchor depth and the soil strength increase, and decreases as the load inclination angle increases. The anchor having square projectional area and being pulled horizontally at the middle of its length provides the highest pullout capacity.

The Method of Hierarchical Emotion Evaluation using Intuitive Categorization (직감적 범주화를 이용한 계층적 감성평가방법)

  • Kim, Don-Han
    • Science of Emotion and Sensibility
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    • v.12 no.1
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    • pp.45-54
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    • 2009
  • Categorization in a vital means for dealing with the multitudes of entities in the world surrounding people. Among others, the perceptual and the evaluative similarities factors strongly affect categorization. The conventional SD-type procedure are insufficient in this regard, since it requires an individual subject to make isolated judgments about each stimulus to identify categorization in terms of a group tendency. It disregards the individual categorization in which the similarities are of great importance. Thus in this study the phased emotional evaluation method is suggested based on the intuitive categorization of stimuli and on the similarity judgement of representative/ non-representative case in each category. To verify the effectiveness of the suggested evaluation method the scanned jewelry images are selected as test stimuli for emotional evaluation experiment. As a result of the evaluation experiment, the conventional SD-type procedure is complemented by the emotional evaluation method in phases of the task of intuitive categorization, the selection of the representative images and the setup of the evaluation score of the representative images to internally supplied anchors of evaluating non-representative images.

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A study of the sinking speed of longlines influenced by bait properties and anchor weights (연승의 침강속도에 영향을 미치는 미끼의 특성과 앵커 무게에 관한 연구)

  • Lee, Ji-Hoon;Lee, Chun-Woo;Karlsen, Ludvig
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.46 no.3
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    • pp.214-222
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    • 2010
  • The paper presents investigations on to which degree the sinking speed of longlines is influenced by type of bait, bait sinking orientations and anchor weights. The main aim of this study is to obtain further insight in the ocean current displacement phenomena in demersal longlining. The sinking speed is one of the main factors deciding the current displacement. In an ongoing project, sinking speed experiments with longlines with 6 kg and 10 kg anchor weights have been carried out in the Trondheim fjord. The longlines used in the first experiments were rigged without bait and hook. The results of these experiments with two different anchor weights have revealed only a slight difference in the sinking speed, except for the part near to the anchors, even though the sinking speed of longlines in general is supposed to be much influenced by the anchor weights. The reason for the obtained result is supposed to be that the experiments have been carried out at relative shallow waters. Further studies have included bait sinking experiments in the flume tank. The experiments showed that the drag coefficient of "fillet type (flat)" bait varied from 0.763 to 1.735, while it for "elliptic type" bait varied from 0.62 to 1.483. Other activities have included calculation of the sinking speed of longlines as a function of the established resistance coefficients of bait of various shape and size for commercial longlining. The calculated sinking speed of a longline with the fillet type bait was found to be 12.4 to 16.5% lower than for a longline without bait.

An Experimental Study on Shear Strengthening Effect of I-girder using Externally Bonded CFRP Strips (외부 부착 탄소섬유를 사용한 I형 보의 전단 보강 효과 연구)

  • Kim, Changhyuk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.4
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    • pp.108-113
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    • 2018
  • Researches on strengthening and rehabilitation methods are being widely conducted due to the deterioration of existing concrete structures. Use of externally bonded Carbon Fiber Reinforced Polymers (CFRP) strips for the rehabilitation is a cost-effective and time-saving method. Generally, the CFRP layout for the shear strengthening was a uni-directional layout. Many researches have focused on the variables of the uni-directional CFRP layout such as the amount of material, angle, and spacing. Pilot tests indicated that the effective confinement of the concrete member can be provided with the bi-directional CFRP layout than the uni-directional layout. Therefore, the test was carried out after the uni- and bi-directional strengthening work using the same amount of CFRP material. CFRP anchors were installed to prevent unexpected premature CFRP delamination failure before reaching CFRP fracture strain. The effectiveness of the CFRP anchor and bi-directional CFRP layout for shear strengthening was verified based on the principal tensile strain contours.

Stability Analysis and Design of Slope Reinforcing Method Using Anchored or Waste Tyre Wall (앵커 또는 폐타이어 벽체를 이용한 사면보강공법의 안정해석 및 설계)

  • 김홍택;강인규
    • Geotechnical Engineering
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    • v.10 no.2
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    • pp.69-84
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    • 1994
  • In the present study, the application of a method of anchored or waste tyre wall in reinforcing the unstable slope is investigated. For design purposes a method of external stability analysis of the reinforced slope, together with a method of internal stability analysis of a wall itself, is presented. In order to predict the passive resistance expected in the anchor or waste tyre Meyerhof's bearing capacity theory is moapaed and experimental results of stress distribution of a pile section under lateral loading is used. Hurray's pull-out teat results are compared with the passive resistances of anchors predicted by the proposed method, and alto the advantages in design are compared with a method of reinforced earth wall with steel strips. Finally a design example of reinforced slope using anchored or caste tyre wall is presented and the overall stability is analyzed in detail by the proposed method of analysis. The efficiency of a method of anchored or waste tyre wall is further analyzed, comparing with a method of changing geometry of the origin리 unstable slope.

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3D FINITE ELEMENT ANALYSIS OF OVERDENTURE STABILITY AND STRESS DISTRIBUTION ON MANDIBULAR IMPLANT-RETAINED OVERDENTURE (하악 임플랜트 유지형 피개의치의 안정성과 하악골 응력분포에 대한 3차원 유한요소법적 연구)

  • Hong, Hae-Ryong;Choi, Dae-Gyun;Bak, Jin;Kwon, Kung-Rock
    • The Journal of Korean Academy of Prosthodontics
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    • v.45 no.5
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    • pp.633-643
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    • 2007
  • Statement of problem: Recently there are on an increasing trend of using implants-especially in edentulous mandible of severly alveolar bone recessed. Purpose: The aim of this study was to analyze the displacement and stress distribution of various mandibular implant-retained overdenture models supported by two implants in interforaminal region under the occlusion scheme load. Material and method: FEA models were made by the 3D scanning of the edentulous mandibular dentiform. The three models were named as Model M1, M2, and M3 accord ing to the position of implants: M1, Lt. incisor area, M2, Canine area, and M3, 1st Premolar area. Inter-implant angulation model was named as M4. Conventional complete denture was named M5 and used as a control group. Ball implant and Gold matrice were used as a retentive anchors. The occlusion type loads were applied horizontally over each tooth. Results: 1. In mandibular implant retained overdenture Canine Protected Occlusion type load resulted in higher levels of stress to the implants and female matrices than other types of loads. 2. The overdenture model M1, with implants in lateral incisor areas resulted in lower stress concentration to the implants and female matrices than other models. 3. In mandibular implant retained overdenture the stresses of the implant and female matrice were lower in mesially inclined implant than these of parallel installed implant. Conclusion: Lateral incisor areas could be the best site for the implants in mandibular implant-retained overdenture. The mandibular implant retained overdenture models mentioned above showed to the lowest stress to the implants and female matrices.

Modified Brostrom Procedure with Suture Anchor & PushLock Anchor in Lateral Ankle Instability (외측 족관절 불안정성 환자에서 봉합 나사와 PushLock Anchor를 이용한 변형 Brostrom 술식)

  • Shin, Sung-Il;Kim, Gab-Lae;Jo, Joo-Sung;Lee, Hyo-Bum;Kwon, Jae-Woo
    • Journal of Korean Foot and Ankle Society
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    • v.16 no.4
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    • pp.241-246
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    • 2012
  • Purpose: The purpose of our study was to perform a comparison of the outcomes of the modified Brostrom procedure using only a suture anchor compared with using a suture anchor with a pushlock anchor. Materials and Methods: This was a retrospective study of chronic lateral ankle instability that underwent a modified Brostrom procedure using a bioabsorbable suture anchor & a pushlock anchor, performed by a single surgeon. A total of 88 patients were enrolled in the study. The function of the patient's ankles were scored using the American Orthopaedic Foot and Ankle Society (AOFAS), visual analogue scale (VAS) both preoperatively and postoperatively. Results: The difference in the overall means between the group A and group B was not statistically significant. But, the patient's satisfaction was better in the group B, and there were more complications in the group A. Conclusion: The technique presented here uses the modified Brostrom procedure with pushlock anchors to prevent the problems associated with subcutaneous knot irritation.

Localization Estimation Using Artificial Intelligence Technique in Wireless Sensor Networks (WSN기반의 인공지능기술을 이용한 위치 추정기술)

  • Kumar, Shiu;Jeon, Seong Min;Lee, Seong Ro
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.9
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    • pp.820-827
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    • 2014
  • One of the basic problems in Wireless Sensor Networks (WSNs) is the localization of the sensor nodes based on the known location of numerous anchor nodes. WSNs generally consist of a large number of sensor nodes and recording the location of each sensor nodes becomes a difficult task. On the other hand, based on the application environment, the nodes may be subject to mobility and their location changes with time. Therefore, a scheme that will autonomously estimate or calculate the position of the sensor nodes is desirable. This paper presents an intelligent localization scheme, which is an artificial neural network (ANN) based localization scheme used to estimate the position of the unknown nodes. In the proposed method, three anchors nodes are used. The mobile or deployed sensor nodes request a beacon from the anchor nodes and utilizes the received signal strength indicator (RSSI) of the beacons received. The RSSI values vary depending on the distance between the mobile and the anchor nodes. The three RSSI values are used as the input to the ANN in order to estimate the location of the sensor nodes. A feed-forward artificial neural network with back propagation method for training has been employed. An average Euclidian distance error of 0.70 m has been achieved using a ANN having 3 inputs, two hidden layers, and two outputs (x and y coordinates of the position).

Eliminating concrete cover separation of NSM strengthened beams by CFRP end anchorage

  • Hosen, Md. Akter;Jumaat, Mohd Zamin;Islam, A.B.M. Saiful;Kamruzzaman, Mohamed;Huda, Md. Nazmul;Soeb, Mahmudur Rahman
    • Structural Engineering and Mechanics
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    • v.56 no.6
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    • pp.899-916
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    • 2015
  • Upgrading or strengthening of existing reinforced concrete (RC) infrastructure is an emerging demand nowadays. Near Surface Mounted (NSM) technique is very promising approach for flexural strengthening of RC members. However, premature failure such as concrete cover separation failure have been a main concern in utilizing this technique. In this study, U-wrap end anchorage with carbon fiber reinforced polymer (CFRP) fabrics is proposed to eliminate the concrete cover separation failure. Experimental programs were conducted to the consequence of U-wrap end anchorage on the flexurally strengthened RC beams with NSM-steel. A total of eight RC rectangular beam specimens were tested. One specimen was kept unstrengthened as a reference; three specimens were strengthened with NSM-steel bars and the remaining four specimens were strengthened with NSM-steel bars and U-wrap end anchorage using CFRP fabrics. A 3D non-linear finite element model (FEM) was developed to simulate the flexural response of the tested specimens. It is revealed that NSM-steel (with and without end-anchors) significantly improved the flexural strength; moreover decreased deflection and strains compared with reference specimen. Furthermore, NSM-steel with end anchorage strengthened specimens revealed the greater flexural strength and improve failure modes (premature to flexure) compared with the NSM-steel without end anchorage specimens. The results also ensured that the U-wrap end anchorage completely eliminate the concrete cover separation failure.

Applicability examinations of induced drainage system for reduction of uplift pressure in underpass structures: Numerical study (지하차도 부력저감을 위한 유도배수공법의 적용성 검토: 수치해석적 연구)

  • Jo, Seon-Ah;Jin, Gyu-Nam;Sim, Young-Jong;Cho, Gye-Chun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.2
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    • pp.123-134
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    • 2013
  • Urban underground structures at low ground elevations (i.e. shallow substructures) unlike typical tunnel structures are subjected to low overburden and high water pressures. This often causes the underground structures to become damaged. Various conventional methods for the urban underpass structures such as dead weight increasement, round anchors, and tension piles, are significantly conservative and provok concerns about the costly, time-consuming installation process. Recently, permanent drainage system becomes to widely use for supplementing the conventional method's shortcomings, but, it is applied without the considerations for ground conditions and water table. In this study, therefore, numerical analyses are performed with various parameters such as groundwater level, wall height, and ground conditions in order to establish design guidelines for induced drainage system which is a kind of the permanent drainage method constructed at the Y-area. According to the numerical results, the induced drainage system is very effective in reducing the uplift pressure that acts on the base of underpass structures.