• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.5
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• pp.111-120
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• 2021

A tractor is an agricultural machine that performs farm work, such as cultivation, soil preparation, loading, bailing, and transporting, through attached working implements. Farm work must be carried out on time per the growing season of crops. As a result, the reliability of a tractor's transmission is vital. Ideally, the transmission's design should reflect the actual load during agricultural work; however, configuring such a measurement system is time- and cost-intensive. The design and analysis of a transmission are, therefore, mainly performed by empirical methods. In this study, a tractor with a measurement system was used to measure the actual working load in the field. Its hydro-mechanical transmission was then analyzed using the measured load. It was found that the velocity factor, load distribution factor, lubrication factor, roughness factor, relative notch sensitivity factor, and life factor affect the gear strength of the transmission. Also, loading conditions have a significant influence on the reliability of the transmission. It is believed that transmission reliability can be enhanced by analyzing the actual load on the transmission, as performed in this study.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.11
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• pp.1679-1685
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• 2022

In this paper, we propose an optimal multi-hop transmission scheme to maximize the end-to-end data rate from the source to the destination node in a wireless powered communication network. The frame structure for multi-hop transmission is presented to transmit multi-hop data while harvesting energy. Then, the transmission time of each node that maximizes the end-to-end transmission rate is determined through mathematical analysis in consideration of different harvested energy and link quality among nodes. We derive an optimization problem through system modeling of the considered wireless powered multi-hop transmission, and prove that there is a global optimal solution by verifying the convexity of this optimization problem. This analysis facilitates to find the optimal solution of the considered optimization problem. The proposed optimal multi-hop transmission scheme maximizes the end-to-end rate by allocating the transmission time for each node that equalizes the transmission rates of all links.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.303-308
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• 2003

In this paper, wave numerical modeling was experimented for the analysis of impact factors for the wave transmission as the incident wave and topographic conditions in the narrow channel sea. Recently, Although the results of many researcher for the wave modelling, numerical equations have limited to simulation of wave transformation effects. Despite of thispresent problems, the models was used to design the coastal structures in barrow channel sites. Finally, this paper estimated the wave model(mild slope eq. model) as the analysis of the wave energy transmission according to changing of impact factors(width of channel, bottom slope in channel, incident wave angle, wave period). As the results of numerical experiment, the major impact factors which influence to wave energy transmission were the width of channel and incident wave direction. But in the case that the width of channel is larger than 3L(L=Length of wave), the reduction of wave energy was small.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.3
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• pp.18-23
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• 2009

This paper focuses on development of new conveyer directly driven by the contact-less energy transmission system. The effect of the resonant circuit and the flux linkage characteristics caused from that are analyzed by using 3D finite element analysis. From the result it is shown that the resonant circuit needs to transfer energy from the primary core to the secondary core. Also the influence of the linear induction motor on the contact-less energy transmission system is presented. New conveyer and the experimental apparatus was manufactured by using the contact-less energy transmission system and the linear induction motor. Possibility of realization of the conveyer is proved by comparison the simulation result which is obtained by using 2D finite element analysis with experimental one and the characteristic of the voltage and resonant current.

• The KIPS Transactions:PartC
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• v.13C no.2 s.105
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• pp.235-240
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• 2006

Stream Control Transmission Protocol (SCTP) provides the multi-homing feature, which allows each SCTP endpoint to use two or more IP addresses for data transmission. In this paper, the SCTP multi-homing feature is experimented and analyzed in terms of throughput over Linux platforms based on the NISTNET network emulator. We perform the experimental analysis of SCTP throughputs by SCTP multi-homing for the various network conditions: different packet loss rates, network bandwidths, and transmission delays. From the experimental results, it is shown that the SCTP multi-homing gives much better throughout gun over the SCTP single-homing case in the networks with a high packet loss rate. In the meantime, the other factors including network bandwidth and transmission delay do not seem to give a significant impact on the performance of the SCTP multi-homing.

• The KIPS Transactions:PartC
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• v.11C no.1
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• pp.123-134
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• 2004

The synchronized clock performance in the synchronization network and SDH transmission network design is an important element in aspect of guaranteeing network stability and data transmission. Consequently the simulator which can applicable various parameters and several input levels from the best state to the worst state for performance analysis of the synchronized clock is required in case of network design. Therefore, in this paper, 1 developed the SNCA and TNCA for analysis of the synchronized clock in the synchronization network and transmission network. And utilizing these simulators with various wander generation, node number and clock state, 1 obtained the synchronized clock characteristics and maximum network nodes In NE1, NE2 and NE3 transmission network and DOTS1, DOTS2 synchronization network.

• Journal of Communications and Networks
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• v.9 no.4
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• pp.473-481
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• 2007

Energy efficiency is one of the most critical concerns for wireless sensor networks. By allowing sensor nodes in close proximity to cooperate in transmission to form a virtual multiple-input multiple-output(MIMO) system, recent progress in wireless MIMO communications can be exploited to boost the system throughput, or equivalently reduce the energy consumption for the same throughput and BER target. However, these cooperative transmission strategies may incur additional energy cost and system overhead. In this paper, assuming that data collectors are equipped with antenna arrays and superior processing capability, energy efficiency of relevant traditional and cooperative transmission strategies: Single-input-multiple-output(SIMO), space-time block coding(STBC), and spatial multiplexing(SM) are studied. Analysis in the wideband regime reveals that, while receive diversity introduces significant improvement in both energy efficiency and spectral efficiency, further improvement due to the transmit diversity of STBC is limited, as opposed to the superiority of the SM scheme especially for non-trivial spectral efficiency. These observations are further confirmed in our analysis of more realistic systems with limited bandwidth, finite constellation sizes, and a target error rate. Based on this analysis, general guidelines are presented for optimal transmission strategy selection in system level and link level, aiming at minimum energy consumption while meeting different requirements. The proposed selection rules, especially those based on system-level metrics, are easy to implement for sensor applications. The framework provided here may also be readily extended to other scenarios or applications.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.30 no.3
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• pp.53-58
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• 2016

The underground transmission lines which have been built to expand the suppling facilities will be continuously accompanying with high growth of the increase of power demand in the metropolitan area in recent years. So, it is necessary to maximize the ability and reliability of power supply with the current-carrying capability of the underground transmission lines. Design criteria of KEPCO is to be presented and used frequently. But it has to be studied about the installation methods of power cable buried in ground. In this study, we used the program for calculating the current-carrying capability of underground transmission power cables. We estimated the maximum permissible current values by the horizontal arrangement in the installation methods of power cable(154kV XLPE $600mm^2$) buried ducts in ground. To see the general tendency of the analysis, we researched a statistical analysis with such parameters as the maximum permissible current values. Through the regression analysis, we analyze the most highly values of the maximum permissible current on the Ra type duct arrangement.

• Journal of Internet Computing and Services
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• v.20 no.2
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• pp.21-27
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• 2019

The terrestrial ATSC 3.0 broadcasting system, which is capable of converging broadcast and communication services, uses IP based technology for data transmission between broadcasting equipment. In addition, data transmission between broadcasting equipment uses IP-based technology like existing wired communication network, which has advantageous in terms of equipment construction and maintenance In case IP based data transmission technology is used, however, it may inevitably cause an error that a packet is lost during transmission depending on the network environments. In order to cope with a broadcasting accident caused by such a transmission error or a malfunction of a broadcasting apparatus, a broadcasting system is generally configured as a duplication, which can transmit a normal packet when various types of error may occur. By this reason, correction method of error packets and intelligent switching technology are essential. Therefore, in this paper, we propose a design and implementation of intelligent IP switch for Ensuring Reliability of ATSC 3.0 Broadcast Streams. The proposed intelligent IP consists of IP Stream Analysis Module, ALP Stream Analysis Module, STL Stream Analysis Module and SMPTE 2022-1 based FEC Encoding/Decoding Module.

• Journal of Welding and Joining
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• v.24 no.6
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• pp.28-32
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• 2006

Laser Transmission Joining (LTJ), which is a joining process of polymers by using different transmission rates of materials, was studied numerically. Unlike previous studies, energy loss by reflection at the surface was included. Besides, energy absorbed in the transparent substrate is also considered to increase the accuracy of the analytical results. Furthermore, thermal deformations of the substrates were also calculated. Temperature distribution of the substrates on the joining process could be effectively predicted by using the thermal analysis model developed, which could also analyze the rising phenomenon of the absorbing substrate by bulge effect. Calculated results show that temperature of the absorbing substrate is higher than that of transparent substrate when the laser is being radiated, and this temperature difference causes more thermal deformation in absorbing substrate, which results in the surface rise of the absorbing substrate. Comparison of calculated results with corresponding experimental results could confirm the validity of the numerical analysis model proposed.