• The Journal of Korea Robotics Society
• /
• v.2 no.2
• /
• pp.168-177
• /
• 2007

In a number of fields, robots are being used for two purposes: efficiency and safety. Most robots, however, have single-actuator mechanism for each joint, where the tasks are performed with high stiffness. High stiffness causes undesired problems to the environment and robots. This study proposes redundant actuator mechanism as an alternative idea to cope with these problems. In this paper, Double-Actuator Unit (DAU) is implemented at each joint for applications of multi-link manipulators. The DAU is composed of two motors: the positioning actuator and the stiffness modulator, which enables independent control of positioning and compliance. A three-link manipulator with DAUs enables adaptive control of RCC. By modulating the joint stiffness of the manipulator and controlling the position of RCC, we can significantly reduce contact force during assembly tasks and surgical procedures.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.10 no.4
• /
• pp.1679-1691
• /
• 2016

Successive interference cancellation (SIC) is an effective means of multi-packet reception to combat interference at the physical layer. We investigate the joint optimization issue of channel access and power control for capacity maximization in SIC-enabled wireless networks. We propose a new interference model to characterize the sequential detection nature of SIC. Afterward, we formulize the joint optimization problem, prove it to be a nondeterministic polynomial-time-hard problem, and propose a novel approximation approach based on the genetic algorithm (GA). Finally, we discuss the design and parameter setting of the GA approach and validate its performance through extensive simulations.

• Smart Structures and Systems
• /
• v.15 no.3
• /
• pp.543-553
• /
• 2015

The condition of the vehicular bridge network in New York City, as represented by ratings obtained during biennial inspections is reviewed over a period of three decades. Concurrently, the bridges comprising the network are considered as networks of structural elements whose condition defines the overall bridge condition according to New York State assumptions. A knowledge-based matrix of assessments is used in order to determine each element's vulnerability and impact within the network of an individual structure and the network of City bridges. In both networks expansion deck joints emerge as the weak link. Typical joint failures are illustrated. Bridge management options for maintenance, preservation, rehabilitation and replacement are examined in the context of joint performance.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.9 no.1
• /
• pp.163-170
• /
• 2001

In this paper, a massless link model transmitting external forces is developed to achieve the numerical efficiency in simulation of vehicle suspension systems. Forces acting on links are resolved and transmitted to attached points with a quasi-static assumption. Also, a theoretical derivation and computer implementation of a massless link with bushing elements are proposed. In the massless link with bushing elements, one end is connected to the adjacent body with bushings and the other end is connected with a spherical joint. The deformation of a massless link with bushing elements is theoretically determined by minimizing the potential energy function with quasi-static equilibrium assumption at each time step. Several simulations with a full vehicle model are carried out to compare the efficiency of the developed massless link component. From the results, it is concluded that the proposed approach can reduce the computational time considerably.

• Journal of the Korea Society of Computer and Information
• /
• v.1 no.1
• /
• pp.25-36
• /
• 1996

We have analyzed the reliability of failure models In grid topology circuit switched networks. These models are grid topology circuit_ switched networks. and each node transmits packets to object node using flooding search routing method. We hypothesized that the failure of each link Is Independent. We have analyzed for the performance estimation of failure models It using joint probability method to the reliability of a small grid topology circuit switched network. and compared analytic output with simulated output. Also. We have evaluated the reliability of networks using call blocking Probability occurred in circuit switched networks.

• Proceedings of the IEEK Conference
• /
• 2000.07a
• /
• pp.125-128
• /
• 2000

In this paper, we derive forward link Erlang capacity reflecting both outage probability and blocking probability of each traffic type in mixed traffics environment. We firstly determine the number of available virtual trunks of the forward link from a circuit switching perspective. Then, capacity sharing model and generalized Erlang model are employed to derive joint Erlang capacity of various traffics types.

• 연구논문집
• /
• s.24
• /
• pp.13-26
• /
• 1994

The choice of design parameters for a robot arm depends on the desired workspace, load lifting capacity, application requirements, and the performance of the robot. The inverse process, which is the determination of a single robot's workspace for a given specification is also a common practice and is as important to the designers as it is to the users. Based on the geometric influence coefficients, the workspace areas on the vertical Y-Z plane are investigated and calculated. Using these areas, the effects of link parameters, link length ratios and joint rotation angles, are investigated.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.06a
• /
• pp.265-270
• /
• 2001

Hip joint simulator which Is an essential device for evaluating the wear of biomaterials (ultrahigh molecular weight polyethylene, Co-Cr alloy, alumina, etc.) used in total hip joint replacement was developed. This hip joint simulator mimics the joint motion and joint loading of human gait by adapting the 4 degree of freedom in kinematic motion (flexing/extension, adduction/abduction, Internal rotation/external rotation) and axial loading, Four stations are operated by 8 servo-motors and harmony drives. Joint leading was imposed by displacement control from a ball screw, LM guide, and spring system. Each kinematic link system operates separately or coupled modes. A heater and a thermocouple were installed for keeping the body temperature in each station.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.11 no.1
• /
• pp.25-32
• /
• 2008

In this paper, we propose how to efficiently apply IP and TDL(Tactical Datalink) protocol to the Link-K network for using their applications on the host system. We classify 3 kinds of communication method between IP network and TDL network. We explain the concepts of Like-to-Like communication (Link-K over IP, IP over Link-K) and Any-to-Any communication. We describe the characteristics and the implementation range of tactical datalink processor for each communication method.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.20 no.2
• /
• pp.264-271
• /
• 2017

Link-K message is the Tactical Data Link message standard developed by the Agency for Defense Development which is optimized for the Joint Operation of ROK Armed Force. KMTF message is the standard message format of Battle Management Information System. Interconversion and propagation between these messages are definitely needed to have efficient warfare such as situation data propagation using network, the convergence of collected situation data, common situational awareness, cooperative engagement. Therefore, this study suggests a way of rule and process for format conversion between Link-K and KMTF messages.