• Title/Summary/Keyword: Joint Action

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Effects of Cognitive Load on the Division of Labor: Working Memory and the Joint Simon Effect (인지 부하가 분업에 미치는 영향: 작업기억과 결합 사이먼 효과)

  • Kim, Hyojeong;Lee, Jaeyoon;Yi, Do-Joon
    • Science of Emotion and Sensibility
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    • v.25 no.2
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    • pp.11-22
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    • 2022
  • As social beings, we need to understand others' actions as quickly and accurately as possible. Action understanding can occur at many levels. We sometimes grasp others' intentions unintentionally. Other times, however, we have to expend effort to draw inferences about their goals. In the context of joint action, the joint Simon effect demonstrates that actors are influenced by the unintended representation of a co-actor's actions. This effect has been described as quasi-automatic, but it is unclear if the effect is automatic enough to be immune to cognitive load. Thus, we asked participants to complete a joint Simon task with or without a concurrent working memory task. One group of participants maintained a single digit in their mind during working memory load blocks (low-load group), while the other group maintained five digits (high-load group). As a result, the low-load group showed a joint Simon effect both during no-load and low-load blocks. In contrast, the high-load group had no joint Simon effect during either no-load or high-load blocks. These results suggest that the joint Simon effect is not an automatic phenomenon given that it requires cognitive resources. Actors in a joint task may represent a co-actor's actions in their task set, but only when cognitive resources are available.

Behavior of composite CFST beam-concrete column joints

  • Kim, Seung-Eock;Choi, Ji-Hun;Pham, Thai-Hoan;Truong, Viet-Hung;Kong, Zhengyi;Duong, Nguyen-The;Vu, Quang-Viet
    • Steel and Composite Structures
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    • v.37 no.1
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    • pp.75-90
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    • 2020
  • This paper introduces a new composite joint, which is the composite CFST beam- concrete column joint, and it is more convenient for transportation and erection than conventionally welded joints. The main components of this joint include steel H-beams welded with CFST beams, reinforced concrete columns, and reinforced concrete slabs. The steel H-beams and CFST beams are connected with a concrete slab using shear connectors to ensure composite action between them. An experimental investigation was conducted to evaluate the proposed composite joint performance. A three-dimensional (3D) finite element (FE) model was developed and analyzed for this joint using the ABAQUS/explicit. The FE model accuracy was validated by comparing its results with the relevant test results. Additionally, the parameters that consisted of the steel box beam thickness, concrete compressive strength, steel yield strength, and reinforcement ratio in the concrete slab were considered to investigate their influence on the proposed joint performance.

Behavior of composite CFST beam-steel column joints

  • Eom, Soon-Sub;Vu, Quang-Viet;Choi, Ji-Hun;Papazafeiropoulos, George;Kim, Seung-Eock
    • Steel and Composite Structures
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    • v.32 no.5
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    • pp.583-594
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    • 2019
  • In recent years, composite concrete-filled steel tubular (CFST) members have been widely utilized in framed building structures like beams, columns, and beam-columns since they have significant advantages such as reducing construction time, improving the seismic performance, and possessing high ductility, strength, and energy absorbing capacity. This paper presents a new composite joint - the composite CFST beam-column joint in which the CFST member is used as the beam. The main components of the proposed composite joint are steel H-beams, CFST beams welded with the steel H-column, and a reinforced concrete slab. The steel H-beams and CFST beams are connected with the concrete slab using shear connectors to ensure composite action between them. The structural performance of the proposed composite joint was evaluated through an experimental investigation. A three-dimensional (3D) finite element (FE) model was developed to simulate this composite joint using the ABAQUS/Explicit software, and the accuracy of the FE model was verified with the relevant experimental results. In addition, a number of parametric studies were made to examine the effects of the steel box beam thickness, concrete compressive strength, steel yield strength, and reinforcement ratio in the concrete slab on the proposed joint performance.

The Effect of the Bolted Joint Stiffness on the Thrust Measurement Stand (볼트의 체결 강성이 추력 시험대에 미치는 영향)

  • Lee, Kyujoon;Jung, Chihoon;Ahn, Dongchan
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.5
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    • pp.31-39
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    • 2016
  • This paper is studied on the effect of the bolt joint stiffness on the Thrust Measurement Stand(TMS). TMS is a test stand for thrust performance of the propulsion system, which depends on two factors: The $1^{st}$ is the parallel degree between directions of the thrust vector and action lines of the corresponding measuring load cells for the vector, and the $2^{nd}$ is the orthogonality between action lines of the measuring load cells. Therefore, it is essential to maintain the original shape of the TMS under operating conditions. In this paper, it is examined how the geometric tolerance of the bolt joints and threads of the load cell trains affect the performance of the TMS. Also, some techniques to overcome related problems are proposed.

A Study on the Behavior of Wall-Support Joint of Steel Plate-Concrete Structure (SC(강판-콘크리트)구조 브라켓 접합부 거동에 관한 연구)

  • Kim, Woo Bum;Kim, Kang Sik
    • Journal of Korean Society of Steel Construction
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    • v.16 no.3 s.70
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    • pp.377-385
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    • 2004
  • An experimental and analytical study on the behavior of the wall-support joint in SC(steel plate-concrete) structure was performed. Nine full-scale specimens were tested with a horizontal monotonic load, all acting in the same plane, causing a uni-axial moment on the SC structure's wall-support beam joint. The main focus is to examine thenonlinear behavior and ultimate strength of the SC wall-support joint. The effects of parameters, such aslocation of support, thickness of the steel plate, and size of support, were studied. The yield strength and ultimate strength of the plate-concrete wall was defined by examining the load-deflection relationship, showing the tension membrane action.

Joint Replenishment Policy for Items with Non-stationary Demands (비정상적 수요를 갖는 품목들의 통합발주정책)

  • Yang, Young-Hyeon;Kim, Jong-Soo;Kim, Tai-Young
    • Journal of Korean Institute of Industrial Engineers
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    • v.38 no.2
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    • pp.116-124
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    • 2012
  • This paper concerns a joint replenishment problem for a single buyer who sells multiple types of items to end-customers. The buyer periodically replenishes the inventory of each item to a preset order-up-to-level to satisfy the end customers' demands, which may be non-stationary. A joint replenishment policy characterized by variable order-up-to-levels is proposed for the buyer who wishes to minimize the expected cost of operating the retail system. The proposed policy starts each period by calculating the expected cost of ordering and not ordering action based on the information of the current inventory position and forecasted demand for the upcoming period. It then takes advantage of an integer programming model to get a cost effective joint replenishment plan. Computer experiment was performed to test efficiency of the proposed policy. When compared with the most efficient policy currently available, our policy showed a considerable cost savings especially for the problems having non-stationary demands.

Seismic Performance Evaluation of Reinforced Concrete Buildings Strengthened by Embedded Steel Frame (내부 매입형 철골조로 보강된 철근콘크리트 건물의 내진 성능평가)

  • Kim, Seonwoong;Lee, Kyungkoo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.24 no.1
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    • pp.29-37
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    • 2020
  • This study is to investigate the effect of a retrofitted reinforced concrete frame with non-seismic details strengthened by embedded steel moment frames with an indirect joint, which mitigates the problems of the direct joint method. First, full-scale experiments were conducted to confirm the structural behavior of a 2-story reinforced concrete frame with non-seismic details and strengthened by a steel moment frame with an indirect joint. The reinforced concrete frame with non-seismic details showed a maximum strength of 185 kN at an overall drift ratio of 1.75%. The flexural-shear failure of columns was governed, and shear cracks were concentrated at the beam-column joints. The reinforced concrete frame strengthened by the embedded steel moment frames achieved a maximum strength of 701 kN at an overall drift ratio of 1.5% so that the maximum strength was about 3.8 times that of the specimen with non-seismic details. The failure pattern of the retrofitted specimen was the loss of bond strength between the concrete and the rebars of the columns caused by a prying action of the bottom indirect joint because of lateral force. Furthermore, methods are proposed for calculation of the specified strength of the reinforced concrete frame with non-seismic details and strengthened by the steel moment frame with the indirect joint.

Three-Dimensional Contact Dynamic Model of the Human Knee Joint During Walking

  • Mun, Joung-Hwan;Lee, Dae-Weon
    • Journal of Mechanical Science and Technology
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    • v.18 no.2
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    • pp.211-220
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    • 2004
  • It is well known that the geometry of the articular surface has a major role in determining the position of articular contact and the lines of action for the contact forces. The contact force calculation of the knee joint under the effect of sliding and rolling is one of the most challenging issues in this field. We present a 3-D human knee joint model including sliding and rolling motions and major ligaments to calculate the lateral and medial condyle contact forces from the recovered total internal reaction force using inverse dynamic contact modeling and the Least-Square method. As results, it is believed that the patella, muscles and tendon affect a lot for the internal reaction forces at the initial heel contact stage. With increasing flexion angles during gait, the decreasing contact area is progressively shifted to the posterior direction on the tibia plateau. In addition, the medial side contact force is larger than the lateral side contact force in the knee joint during normal human walking. The total internal forces of the knee joint are reasonable compared to previous studies.

Effects of Steel Fiber Reinforcement and the Number of Hooked Bars at R/C Exterior Joints

  • Choi, Ki-Bong
    • KCI Concrete Journal
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    • v.11 no.3
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    • pp.181-189
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    • 1999
  • An experimental study was performed on the Pull-out behavior of 90-deg standard hooks from the exterior beam-column connections. the effects of the number of hooked bars and fiber reinforcement of the joint area were investigated with the following conclusions : (1) Under the pull-out action of hooked bars. the damage and cracking of joint area the number of hooks pulling out from a joint increases; (2) Substitution of the transverse column (confining) reinforcement with steel fibers at the joint region effectively reduces the extent of cracking in exterior joints caused by the pull-out of hooked bars; (3) The pull-out strength and post-peak ductility of hooked bars are adversely influenced by the increase in number of hooks pulling out from an exterior joint. Current hooked bar anchorage design guidelines may be improved by considering the effect of the number of hooked bars on anchorage conditions at the exterior joints; and (4) The strength and ductility of hooked bars under pull-out forces are positively influenced by substituting the conventional confining reinforcement of exterior joints with steel fibers . The application of steel fibers to the exterior joints is an effective technique for improving the anchorage conditions of hooked bars, and also for reducing the congestion of reinforcement in the beam-column connections.

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Localization and a Distributed Local Optimal Solution Algorithm for a Class of Multi-Agent Markov Decision Processes

  • Chang, Hyeong-Soo
    • International Journal of Control, Automation, and Systems
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    • v.1 no.3
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    • pp.358-367
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    • 2003
  • We consider discrete-time factorial Markov Decision Processes (MDPs) in multiple decision-makers environment for infinite horizon average reward criterion with a general joint reward structure but a factorial joint state transition structure. We introduce the "localization" concept that a global MDP is localized for each agent such that each agent needs to consider a local MDP defined only with its own state and action spaces. Based on that, we present a gradient-ascent like iterative distributed algorithm that converges to a local optimal solution of the global MDP. The solution is an autonomous joint policy in that each agent's decision is based on only its local state.cal state.