• Journal of electromagnetic engineering and science
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• v.10 no.2
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• pp.50-55
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• 2010

Orthogonal Frequency Division Multiplexing(OFDM) dual-hop systems can take full advantages of the techniques of both multi-hop communication and OFDM. To achievethis end, we propose a joint subcarrier matching, power allocation and bit loading algorithm operating under a total power constraint and the same Bit Error Rate(BER) threshold over all subcarriers. Simulation results demonstrated system throughput improvement compared to single-hop systems and dual-hop systems with different bit loading algorithms for each relay position, power constraint, and required BER.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.5
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• pp.496-501
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• 2015

In this study, calibration procedure of power assembly tools is suggested and methods are developed for calculating measurement uncertainty. Fist of all, the calibration of joint simulator bench (JSB) was carried out for maintaining traceability and the uncertainty components of JSB were analyzed. The influences of tool speed, tolerance, temperature and length of the adapter were examined by the torque measurement values through experiments. From this research, credibility for calibration results could be enhanced. This experimental results, being used as an effective tool for calibration of power assembly tools, will provide and improve the accuracy of the use of the power assembly tools.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3326-3333
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• 2023

The results of the analysis of a mathematical modeling for the IBR-2M pulsed reactor dynamics for a transition from a power pulse repetition frequency of 5 Hz-10 Hz are presented. The change in the amplitude response of the reactor for variable pulse delayed neutron fraction was studied. We used a set of power feedback parameters determined experimentally in 2021 at an energy output of 1820 MW·day. At a pulse repetition frequency of 10 Hz, the amplitude of pulse energy oscillations significantly depends on the value of the delayed neutron fraction in pulse β_p. Depending on β_p both suppression and amplification of reactor power fluctuations in the frequency ranges of 0.05-0.20 and 1.25-5.00 Hz can be realized.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.3
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• pp.35-44
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• 2009

The purpose of this paper is to describe experimental results about the T-joint welding of the high power continuous wave (CW) fiber laser for SAPH steel plate for seat frame of car. The seat rail is a part of seat frame of cars. The assembling method is mostly fix up using a bolt and nut. But this assembling method has many demerits in productivity such as increasing work process and material cost. This paper presents an experimental study about Laser T-Joint weldability of seat rail. Laser welding has many advantages in lightness and saving material costs of seat frame. The laser beam was moved along the work pieces by six axis robot with process optical fiber. The laser beam is focused with a welding head within incident angle $15{\sim}45^{\circ}$ for the purpose of the T-joint welding through two side full penetration. The range of the root gap size is less than ${\leq}0.4mm$. Optical microscopy SEM were performed to observe the micro structures and determine the structures of welded zone.

• Journal of Information Processing Systems
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• v.17 no.4
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• pp.721-736
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• 2021

For the mobile edge computing (MEC) system supporting dense network, a joint allocation algorithm of computing and communication resources based on reinforcement learning is proposed. The energy consumption of task execution is defined as the maximum energy consumption of each user's task execution in the system. Considering the constraints of task unloading, power allocation, transmission rate and calculation resource allocation, the problem of joint task unloading and resource allocation is modeled as a problem of maximum task execution energy consumption minimization. As a mixed integer nonlinear programming problem, it is difficult to be directly solve by traditional optimization methods. This paper uses reinforcement learning algorithm to solve this problem. Then, the Markov decision-making process and the theoretical basis of reinforcement learning are introduced to provide a theoretical basis for the algorithm simulation experiment. Based on the algorithm of reinforcement learning and joint allocation of communication resources, the joint optimization of data task unloading and power control strategy is carried out for each terminal device, and the local computing model and task unloading model are built. The simulation results show that the total task computation cost of the proposed algorithm is 5%-10% less than that of the two comparison algorithms under the same task input. At the same time, the total task computation cost of the proposed algorithm is more than 5% less than that of the two new comparison algorithms.

• Journal of the Korean Society for Precision Engineering
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• v.31 no.7
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• pp.643-649
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• 2014

In order to demonstrate the possibility of applying an ionic polymer metal composite (IPMC) to a finger exoskeleton, pinching motion analysis was performed for a thumb-index finger dummy actuated by IPMC actuators. The IPMC actuators of 5mm in width and 40mm in length with 2.4mm thickness generated 1.52N of blocking force for the applying voltage of 4.0V. Three actuators were installed on the three rotary joint of an index finger, and one actuator was installed on one proximal joint. Positions of each joint and finger tip were recorded on the video camera, and motion was analyzed. Power supply to the index finger actuators preceded power supply to the thumb actuator, and key pinching motion was accomplished in 180s. Tip pinching was accomplished in 135s as power supply to the thumb preceded power supply to the index finger.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1608-1610
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• 1998

An oil-filled paper-insulated power cable and a XLPE-insulated power cable have been mainly applied as an extra-high-voltage underground power cable. But in recent the XLPE cable has been applied more widely than the OF cable, because of its advantages, such as the low-cost and simple installation. In general two types, molded and prefabricated, of straight joints are applied for the XLPE cables. For a tape-molded joint, one of molded joints, its electrical properties are excellent, but it has some disadvantages, such as a long working time. high skill of workers and the high cost of jointing equipments. For a prefabricated joint, developed and applied in Europe and Japan, its working time is short, its jointing procedures are simple, and its quality control is easy, but its prices are very high. In Korea the development of a compression-type PJ will be finished in the near future, and studies of its jointing techniques and equipments is actively going on. This paper describes the design and construction of the PJ, the jointing procedures and techniques for the PJ, and its future trends.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.10
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• pp.993-1003
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• 2012

This paper presents a method for joint analysis of combat power and communication system performance via interoperation of a war game simulator and a communication network simulator using HLA/RTI. Effectiveness analysis of combat power has been performed by war game simulation with consideration of communication effects simulated by the network simulator. Performance analysis of a communication system has been performed by network simulation with computer forces generated by the war game simulator. Survivability of the red force and transmission power of a tactical FM radio for the blue force have been measured for the joint analysis.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5614-5633
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• 2018

Mobile Edge Computing (MEC) and Wireless Power Transfer (WPT) are both recognized as promising techniques, one is for solving the resource insufficient of mobile devices and the other is for powering the mobile device. Naturally, by integrating the two techniques, task will be capable of being executed by the harvested energy which makes it possible that less intrinsic energy consumption for task execution. However, this innovative integration is facing several challenges inevitably. In this paper, we aim at prolonging the battery life of mobile device for which we need to maximize the harvested energy and minimize the consumed energy simultaneously, which is formulated as residual energy maximization (REM) problem where the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device are all considered as key factors. To this end, we jointly optimize the offloading ratio, energy harvesting time, CPU frequency and transmission power of mobile device to solve the REM problem. Furthermore, we propose an efficient convex optimization and sequential unconstrained minimization technique based combining method to solve the formulated multi-constrained nonlinear optimization problem. The result shows that our joint optimization outperforms the single optimization on REM problem. Besides, the proposed algorithm is more efficiency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1998.04a
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• pp.311-318
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• 1998

In this paper, the power flow analysis(PFA) method is applied to the prediction of the vibrational energy density and intensity of coupled co-planar plates. To cover the energy transmission and reflection at the joint of the plates, the wave transmission approach is introduced with the assumption that all the incident waves are normal to the joint. By changing the frequency ranges and internal loss factors, we have obtained the PFA results, and compared them with the analytical exact solutions.