• Journal of the Korean Society of Systems Engineering
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• v.16 no.2
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• pp.67-77
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• 2020

Traditionally nuclear thermal hydraulic and nuclear safety has relied on numerical simulations to predict the system response of a nuclear power plant either under normal operation or accident condition. However, this approach may sometimes be rather time consuming particularly for design and optimization problems. To expedite the decision-making process data-driven models can be used to deduce the statistical relationships between inputs and outputs rather than solving physics-based models. Compared to the traditional approach, data driven models can provide a fast and cost-effective framework to predict the behavior of highly complex and non-linear systems where otherwise great computational efforts would be required. The objective of this work is to develop an AI algorithm to predict the peak fuel cladding temperature as a metric for the successful implementation of FLEX strategies under extended station black out. To achieve this, the model requires to be conditioned using pre-existing database created using the thermal-hydraulic analysis code, MARS-KS. In the development stage, the model hyper-parameters are tuned and optimized using the talos tool.

• Journal of Korea Society of Industrial Information Systems
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• v.27 no.2
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• pp.53-59
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• 2022

In this paper, a mobile robot capable of remote control is designed in consideration of the user's various work environments. Specifically, a mobile remote work robot that moves in a predetermined direction and can perform a series of tasks in synchronization with the user's hand movements, and a control system and control method for controlling the robot were proposed. It was implemented using a robot hand and a wheel for movement to assist in tasks such as transporting dangerous goods or heavy goods. In order to evaluate the performance of the developed robot, the maximum weight that can be carried by the robot hand and the movable inclination of the robot were tested, and the test evaluation results satisfied most of the targeted design specifications.

• Journal of the Korean Society of Safety
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• v.38 no.3
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• pp.110-120
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• 2023

Following the Fukushima accident, portable equipment employed as accident mitigating systems have been installed and operated to reduce core damage and large early release frequencies. In addition, the establishment of an accident management strategy has gained importance. This study investigated the current status of portable equipment including the international portable equipment FLEX (diverse and flexible coping strategies), and domestic portable equipment multi-barrier accident coping strategy (MACST). Research on optimal utilization of MACST remains insufficient. As a preliminary study for establishing an optimal strategy, sensitivity studies were conducted to facilitate the priority of use on portable equipment, number of portable equipment, and dependency of operator actions based on a multi-unit probabilistic safety assessment model. The results revealed the conditions that reduced the multi-unit and site conditional core damage probabilities, indicating the optimal strategy of MACST. The results of this study can be used as a reference for establishing an optimal strategy that utilizes domestic safety equipment in the future.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.9
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• pp.2377-2398
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• 2023

In our daily lives, we engage in a variety of tasks that rely on our senses, such as seeing. Blindness is the absence of the sense of vision. According to the World Health Organization, 2.2 billion people worldwide suffer from various forms of vision impairment. Unfortunately, blind people face a variety of indoor and outdoor challenges on a daily basis, limiting their mobility and preventing them from engaging in other activities. Blind people are very vulnerable to a variety of hazards, including falls. Various barriers, such as stairs, can cause a fall. The Internet of Things (IoT) is used to track falls and send a warning message to the blind caretakers. One of the gaps in the previous works is that they were unable to differentiate between falls true and false. Treating false falls as true falls results in many false alarms being sent to the blind caretakers and thus, they may reject the IoT system. As a means of bridging this chasm, this paper proposes an intelligent shoe that is able to precisely distinguish between false and true falls based on three sensors, namely, the load scale sensor, the light sensor, and the Flex sensor. The proposed IoT system is tested in an indoor environment for various scenarios of falls using four models of machine learning. The results from our system showed an accuracy of 0.96%. Compared to the state-of-the-art, our system is simpler and more accurate since it avoids sending false alarms to the blind caretakers.

• Journal of Bio-Environment Control
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• v.17 no.2
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• pp.176-180
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• 2008

In days to calyx-flex stage test, flower development affected by light intensity, light duration and the prevailing temperature. As, 'Jacaranda' variety shorter in under 46 days of flower bud formation and 13 days of calyx-flex stage than the other variety with 'Queen Elizabeth' control variety. About cut flower only 'Grand Vicki Brown' (as within 46 days of flower formation, 13 days of calyx stage and 'Jacaranda', both with shorter plants than the other varieties produced cut flower classified as short and medium-stemmed cut flowers. 'Jacaranda', 'Vicki Brown', 'Golden Times', 'Champagne', 'Osiana', and 'Queen Elizabeth (control variety)' flowered earlier from 46.7 to 50.8 days from pruning. Flower development was likewise faster in all the above mentioned cultivars; while 'Tineke' had significantly delayed flower development reaching calyx-flex stage from 0.5 cm bud size after 51.0 days. The top ten high yielding varieties were 'American Orange', with a net income of P3,081,676.00; 'Yellow Island' with P1,572,874.00; 'Frosty Pink' with P1,085,183.00; 'Champagne' with P980,620.00; 'Coral Pink' with P959,669.00; 'Lara Pink' with P918,444.00; 'Lara Orange' with P714,252.00; 'Grand Gala' with P705,787.00; 'Golden Times' with P806,489.00; and 'Lady X' with P778,060.00 net returns.

• Proceedings of the IEEK Conference
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• 2000.06a
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• pp.77-80
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• 2000

In this paper, we implemented the voice modem using the multicarrier DS-CDMA in powerline channels. Both TMS320C5402 of Texas Instrument and FPGA FLEX 10K EPF10K100ARC240 of ALTERA are used to realize the proposed system. For robustness in the powerline channel, we used multicarrier DS-CDMA modulation, convolutional encoding/Viterbi decoding, and interleaving. Finally, we showed satisfactory performance in the laboratory experiment.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10b
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• pp.544-546
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• 1998

소프트웨어 프로세스 모형은 실세계 소프트웨어 프로세스의 개념적인 표현이다. 소프트웨어 프로세스 모형들은 프로세스 프로그래밍 언어를 통해 추상화됨으로써 모형화 될 수 있으며, 프로세스 모형들을 자동으로 수행(enactment)하고, 이미 수행된 프로세스 모형들을 체계적으로 관리하는 수행지원시스템을 통해서 소프트웨어 생산물의 질적인 향상을 기대할 수 있다. 본 논문에서는 소프트웨어 프로세스의 수행 중에 발생할 수 있는 프로세스의 feedback을 지원하는 SimFlex 프로세스 프로그래밍 언어의 확장된 언어구조와 프로세스 수행지원 시스템인 SEED 엔진에서의 효과적인 feedback 지원 방법에 대하여 설명한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.831-837
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• 1999

본 논문에서는 Viterbi 복호기의 동작을 고속화할 수 있는 구조를 제시하였고, 제시된 방식으로 설계된 Viterbi 복호기를 CPLD 칩으로 구현하였다. Altera사의 Design Compiler를 이용하여 FLEX10K 칩에 합성한 Viterbi 복호기는 최고 20[Mbps]급 전송속도를 갖고 있으며, ASIC 설계시 100Mbps 이상의 속도가 가능하므로 고속 무선멀티미디어통신 시스템의 오류정정부호로 적용될 수 있다.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.181-185
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• 2000

To get high efficiency in variable speed control of induction motor it is required that the vector control should be separated from flux components current and torque component current. In this paper the vector control is modeled by the estimation of the stator flex. Representing induction motor speed controller as a digital system with he use of he 32bit DSP improves the motor control performance The IGBT is used as the switching device and the validity of the proposed vector control is proved through voltage current wave and the characteristics of the velocity response as the drive circuit being simplified

• Bulletin of the Korean Mathematical Society
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• v.55 no.2
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• pp.611-624
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• 2018

In this paper, we study Weierstrass semigroups of ramification points on double covers of plane curves of degree 6. We determine all the Weierstrass semigroups when the genus of the covering curve is greater than 29 and the ramification point is on a total flex.