• Journal of Astronomy and Space Sciences
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• v.13 no.2
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• pp.20-29
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• 1996

Provision of the electrical power generated from solar array is one of the most fundamental requirements for the spacecraft payloads. Power subsystem collects, regulates and distributes power to the experiment payloads and to the various spacecraft subsystem. In this paper, the analysis result of the KITSAT-1 WOD shows that the in-orbit operation of whole power system has been in good condition.

• Convergence Security Journal
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• v.24 no.3
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• pp.41-49
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• 2024

A tokenizer, which is a key component of the Transformer model, lacks the ability to effectively comprehend numerical data. Therefore, to develop a Transformer-based intrusion detection model that can operate within a real-world network environment by training packet payloads as sentences, it is necessary to convert the hexadecimal packet payloads into a character-based format. In this study, we applied three character encoding methods to convert packet payloads into numeric or character format and analyzed how detection performance changes when training them on transformer architecture. The experimental dataset was generated by extracting packet payloads from PCAP files included in the UNSW-NB15 dataset, and the RoBERTa was used as the training model. The experimental results demonstrate that the ISO-8859-1 encoding scheme achieves the highest performance in both binary and multi-class classification. In addition, when the number of tokens is set to 512 and the maximum number of epochs is set to 15, the multi-class classification accuracy is improved to 88.77%.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.2
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• pp.145-149
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• 2015

This paper introduces a sway suppression control for container cranes with unknown payloads and sway rates. With no priori knowledge concerning the magnitude of payload mass and sway rate, the proposed control maintains superior sway suppressing and trolley positioning against external disturbances. The proposed scheme combines a second order sliding mode control and an adaptive control to cope with unknown payloads. A second order sliding mode control without feedback of the sway rate is first designed, which is based on a class of feedback linearization methods for stabilization of the under-actuated sway dynamics of the container. Under applicable restrictions of the magnitude of payload inertia and sway rate, a linear regression model is obtained, and an adaptive control with a payload estimator is then designed, which is based on Lyapunov stability methods for the fast attenuation of trolley oscillations in the vicinity of the target position. The asymptotic stability of the overall closed-loop system is assured irrespective of variations of rope length. Simulation are shown in the existence of initial sway and external wind disturbances.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.2
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• pp.80-88
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• 2003

This paper describes the development of an ozone detector and an electron probe as parts of scientific payloads for sounding rockets such as the KSR-III. Each detector consists of sensor parts and electronic parts. We successfully carried out the calibration tests with developed ozone detector and the space plasma simulation chamber tests with electron detector. These payloads could be onboard the KSR-III and with measured data, it is expected and temperature profile over the Korean Peninsular.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.6
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• pp.1117-1119
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• 2015

In this letter, we propose a mathematical model of variable-length payloads transmitted in EDCA and transmitted using MU-MIMO. Assuming fixed-length or the use of mean value of payload length leads to discordant results while calculating the total payload length of variable-length frames transmitted within a fixed duration. Using the proposed model results in accurate results (less than 3% relative errors) for total payload length under variable-length traffic.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.68-74
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• 2009

Infra-red earth sensors(IRES) are accommodated in a geostationary multi-functional satellite, which includes optical payloads for observing the earth, to provide pointing reference for the payloads. Even the slight pointing difference between the IRES and the payloads is so critical from the geostationary orbit that can degrade their imaging performance. Therefore, a dedicated support structure is required to guarantee the stability during the flight operation. This paper shows the design justification for the IRES support structure employed in the Communication, Ocean and Meteorological Satellite(COMS). It intends to give an overall design presentation and to justify that this design is compatible with all the requirements in terms of stiffness and strength as well as the stability.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1482-1482
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• 2003

• Journal of the Korean Society for Precision Engineering
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• v.2 no.1
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• pp.41-52
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• 1985

This study is a step in developing the sliding mode control methodology for the robust control of a class of nonlinear time-varying systems. The methodology uses in its idealized form piecewise continuous feedback control, resulting in the state trajectory "sliding" slong a time-varying sliding surface in the state space. This idealized control law achieves perfect tracking. The method is applied to the control of a two-link manipulator handling variable loads in a flexible manufacturing system environment with noise. The result through simulation is that the tracking problem of articular robot with high precision can be realized by using the variable structure system (VSS) theory. The motions of articular robot were insensitive to various payloads. payloads.

• Aerospace Engineering and Technology
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• v.6 no.1
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• pp.92-96
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• 2007

The conventional commands & telemetry system of Korean low-earth orbiting satellites has certain limitations in accommodating various missions. As the payload becomes complex, it requires very complicated operational concepts in terms of commands and telemetry. With the current design, commands and telemetry formats have to be rebuilt whenever new payloads or operation concepts are involved, and many constraints in operation shall be produced due to the lacks of its flexibility. In this paper, a new strategy for commands & telemetry development partially derived from PUS (Packet Utilization Standard) of European Space Agency, which provides enhanced features for the accommodation of payloads & operational requirements, is presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.543-548
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• 2006

This paper presents the vibration characteristics of scaffolding structures with a hoist according to payloads. In order to analyze the vibrational and structural characteristics for 20-step scaffolding structure, structural and vibrational characteristics for 2-step scaffolding structure were compared with some experimental results. The numerical results for natural frequencies of scaffolding structures have a good agreement with experimental ones. Through the numerical analysis, firstly, it is shown that the maximum stress of scaffolding structures is lower than von-mises yield criteria when four persons with total weight of 280kgf are working at the top of the scaffolding structures. Secondly vibration characteristics including natural frequencies and modes for scaffolding structures are shown in case of various kinds of moving masses.