• Steel and Composite Structures
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• v.18 no.6
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• pp.1423-1450
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• 2015

The paper presents the details and results of an experimental study on bolted end-plate joints of industrial type steel building frames. The investigated joints are commonly used in Lindab-Astron industrial buildings and are optimized for manufacturing, erection and durability. The aim of the research was to provide an experimental background for the design model development by studying load-bearing capacity of joints, bolt force distribution, and end-plate deformations. Because of the special joint details, (i.e., joints with four bolts in one bolt-row and HammerHead arrangements), the Eurocode 3 standardized component model had to be improved and extended. The experimental programme included six different end-plate and bolt arrangements and covered sixteen specimens. The steel grade of test specimens was S355, the bolt diameter M20, whereas the bolt grade was 8.8 and 10.9 for the two series. The end-plate thickness varied between 12 mm and 24 mm. The specimens were investigated under pure bending conditions using a four-point-bending test arrangement. In all tests the typical displacements and the bolt force distribution were measured. The end-plate plastic deformations were measured after the tests by an automatic measuring device. The measured data were presented and evaluated by the moment-bolt-row force and moment-distance from centre of compression diagrams and by the deformed end-plate surfaces. From the results the typical failure modes and the joint behaviour were specified and presented. Furthermore the influence of the end-plate thickness and the pretension of the bolts on the behaviour of bolted joints were analysed.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.254-259
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• 1992

In this paper, we propose an optimal method for the tracking a trajectory of the end-effector of flexible robot arms with multiple joints. The proposed method finds joint trajectories and joint torques necessary to produce the desired end-effector motion of flexible manipulator. In inverse kinematics, optimized joint trajectories are computed from elastic equations. In inverse dynamics, joint torques are obtained from the joint equations by using the optimized joint trajectories. The equations of motion using finite element method and virtual work principle are employed. Optimal control is applied to optimize joint trajectories which are computed in inverse kinematics. The simulation of flexible planner manipulator is presented.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.184-191
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• 2003

A parallel manipulator has high stiffness and all the joint errors on the device are not accumulated at the end -effector unlike a serial manipulator. These are the reasons why the parallel manipulator has been widely used in many fields of industry. In the parallel manipulator, it is very important to predict the exact pose of the end-effector when we want to control the end-effector motion. Installation errors have to be determined in order to predict and control the actual position and pose of the end-effector. This paper presents an algorithm to find the whole 36 joint error components with joint clearance errors and measurement errors considered, when a link length measurement sensor is used and data more than 36 times are acquired for 36 different configurations. A simulation test using this algorithm is performed with a Matlab program which uses the Levenberg-Marquardt method that is known to be efficient for non-linear optimization.

• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.311-317
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• 2019

Direct teaching is an essential function for collaborative robots for easy use by non-experts. For most robots, direct teaching is implemented only in joint space because the realization of Cartesian space direct teaching, in which the orientation of the end-effector is fixed while teaching, requires a measurement of the end-effector force. Thus, it is limited to the robots that are equipped with an expensive force/torque sensor. This study presents a Cartesian space direct teaching method for torque-controlled collaborative robots without either a force/torque sensor or joint torque sensors. The force exerted to the end-effector is obtained from the external torque which is estimated by the disturbance observer-based approach with the friction model. The friction model and the estimated end-effector force were experimentally verified using the robot equipped with joint torque sensors in order to compare the proposed sensorless approach with the method using torque sensors.

• Journal of muscle and joint health
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• v.30 no.2
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• pp.111-119
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• 2023

Purpose: The purpose of this study was to describe end-of-life care stress, compassionate competence, and job satisfaction among nurses caring for cancer patients and to identify the relationship between variables. Methods: The participants comprised 141 nurses at the D cancer center in Busan metropolitan city. Data were collected from October 14 to the 31, 2022. The data were analyzed using the SPSS/WIN 29.0 program. Results: There was a significantly positive correlation between a participnat's job satisfaction and compassionate competence (r=.45, p<.001), and end-of-life care stress (r=.42, p<.001). Conclusion: Compassionate competence and end-of-life care experience among nurses caring for cancer patients are factors that influence job satisfaction. A program that can improve compassionate competence should be developed to improve job satisfaction.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.2022-2026
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• 2003

We define that the end effector is the device which interact environment or objects with contact to execute tasks. Up to now, many researchers developed anthropomorphic robotic hands as end effectors. In this paper, we will discuss a problem on the development of a human-scale and motor-driven anthropomorphic robot hand. In this paper, design concept, actuator and transmission, kinematic design and sensing device are presented. By imitating the physiology of human hands, we devised new metacarpalphalangeal joint and interphalangeal joint suitable for human-size robot hands

• Journal of Communications and Networks
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• v.11 no.3
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• pp.297-305
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• 2009

Multiprotocol label switching (MPLS) networks require dynamic flow admission control to guarantee end-to-end quality of service (QoS) for each Internet protocol (IP) traffic flow. In this paper, we propose to tackle the joint routing and admission control problem for the IP traffic flows in MPLS networks without rerouting already admitted flows. We propose two mathematical programming models for this problem. The first model includes end-to-end delay constraints and the second one, end-to-end packet loss constraints. These end-to-end QoS constraints are imposed not only for the new traffic flow, but also for all already admitted flows in the network. The objective function of both models is to minimize the end-to-end delay for the new flow. Numerical results show that considering end-to-end delay (or packet loss) constraints for all flows has a small impact on the flow blocking rate. Moreover, we reduces significantly the mean end-to-end delay (or the mean packet loss rate) and the proposed approach is able to make its decision within 250 msec.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.554-565
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• 2012

In this paper, we study a cross-layer and end-to-end optimization problem for the integrated wireless and wireline network that consists of one wireline core network and multiple wireless access networks. We consider joint end-to-end flow control/distribution at the transport and network layers and opportunistic scheduling at the data link and physical layers. We formulate a single stochastic optimization problem and solve it by using a dual approach and a stochastic sub-gradient algorithm. The developed algorithm can be implemented in a distributed way, vertically among communication layers and horizontally among all entities in the network, clearly showing what should be done at each layer and each entity and what parameters should be exchanged between layers and between entities. Numerical results show that our cross-layer and end-to-end optimization approach provides more efficient resource allocation than the conventional layered and separated optimization approach.

• Steel and Composite Structures
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• v.26 no.4
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• pp.463-471
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• 2018

The bolted end-plate beam-column connections have been widely used in steel structure and composite structure because of its excellent seismic performance. In this paper, the end-plate bolted connection is applied in the concrete structure, A new-type of fabricated beam-column connections with end-plates is presented, and steel plate hoop is used to replace stirrups in the node core area. To study the seismic behavior of the joint, seven specimens are tested by pseudo-static test. The experimental results show that the new type of assembly node has good ductility and energy dissipation capacity. Besides, under the restraint effect of the high-strength stirrup, the width of the web crack is effectively controlled. In addition, based on the analysis of the factors affecting the shear capacity of the node core area, the formula of shear capacity of the core area of the node is proposed, and the theoretical values of the formula are consistent with the experimental value.

• Steel and Composite Structures
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• v.46 no.4
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• pp.539-551
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• 2023

In order to study the fire resistance of castellated composite beams with ortho-hexagonal holes and different beam-end restraints, temperature rise tests with constant load were conducted on full-scale castellated composite beams with ortho-hexagonal holes and hinge or rigid joint constraints to investigate the temperature distribution, displacement changes and failure patterns of castellated composite beams with two different beam-end constraints during the whole course of fire. The results show that (1) During the fire, the axial pressure and horizontal expansion deformation generated in the rigid joint constrained composite beam were larger than those in the hinge joint constrained castellated composite beam, and their maximum horizontal expansion displacements were 30.2 mm and 17.8 mm, respectively. (2) After the fire, the cracks on the slab surface of the castellated composite beam with rigid joint constraint were more complicated than hinge restraint, and the failure more serious; the lower flange and web at the ends of the castellated steal beams with hinge and rigid joint constraint produced serious local buckling, and the angles of the ortho-hexagonal holes at the support cracked; the welds at both ends of the castellated composite beam with rigid joint constraint cracked. (3) Based on the simplified calculation method of solid-web composite beam, considering the effect of holes on the web, this paper calculated the axial force and displacement of the beam-end constrained castellated composite beams under fire. The calculation results agreed well with the test results.