• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.532-543
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• 1995

In this study, a transport model was developed in order to analyze and predict the transport behaviors of radionuclides mediated by pseudo-colloid in the fractured rock media. The effect of pseudo-colloid formation on the transport of a radionuclide was shown to be tory significant when an ap-parent pseudo-colloid formation constant, $A_{ap}$ (㎥/kg), os greater than 100. It was resulted from example calculations that the transport of Pu-239 was faster than Ni-63 because pseudo-colloid formation constant of Pu-239 was venter than that of Ni-63. Thus, it can be concluded that acceleration of radionuclide migration may be occurred because the pseudo-colloid formation of radionuclides increases the amount of mobile components in the solution and consequently decreases the amount of radionuclides adsorbed on the stationary solid medium.

• International Journal of Internet, Broadcasting and Communication
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• v.16 no.4
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• pp.133-140
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• 2024

In strawberry cultivation, maturity classification plays an important role in ensuring the efficiency and quality of harvesting. In this study, we propose an Improved Faster R-CNN model to address these challenges, using MobileNetV3-Large as the backbone network to achieve a lightweight model, and introducing RoI Align to improve the spatial accuracy of the feature map. Experiments are conducted using the KGCV_Strawberry dataset, with precision, recall, F1 score, and mean average precision (mAP) measured for performance evaluation. The experimental results show that the proposed model achieves an average precision of 71.35%, recall of 71.07%, and F1 score of 71.21% across all classes. In particular, the proposed model achieves 63% performance on mAP0.5 and 58% performance on mAP0.5:0.95, which is comparable to existing ResNet-based models while achieving faster inference speed. The proposed model achieves a processing speed of 27.6543 ms, which is about 2 ms faster than existing ResNet-based models. This indicates that the goal of creating a lightweight model with improved image processing capability was achieved with minimal performance degradation. This research is expected to contribute to the development of automated strawberry cultivation systems in greenhouse environments and has the potential to be applied to various agricultural environments in the future.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.804-809
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• 2004

This paper introduces a link-type tracked vehicle which is developed for demining operations. The vehicle consists of three parts - front frame, rear frame and body. The front frame is connected to the rear frame by a rotational passive adaptation mechanism which is a driving mechanism of the vehicle. Additionally, the demining system which is adaptable to mobile robot is developed to clear small Anti-Personnel(AP) mines with inexplosive method. In other words, assembled rakes unearth mines by their opposite rotation to the direction of the robot. Finally, the motions of demining rakes and design parameters of the demining system are analyzed.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1286-1291
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• 2017

In this paper, we propose an indoor positioning system that makes use of the attenuation model for IEEE 802.11 Channel State Information (CSI) in order to determine its distance from an Access Point (AP) at a fixed position. With the use of CSI, we can mitigate the problems present in the use of Received Signal Strength Indicator (RSSI) data and increase the accuracy of the estimated mobile device's location. For the experiments we performed, we made use of the Intel 5300 Series Network Interface Card (NIC) in order to receive the channel frequency response. The Intel 5300 NIC differs from its counterparts in that it can obtain not only the RSSI but also the CSI between an access point and a mobile device. We can obtain the signal strengths and phases from subcarriers of a system which in turn means making use of this data in the estimation of a mobile device's position.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.6B
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• pp.420-429
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• 2008

Currently, IEEE 802.11 Network could not support optimized tunneling scheme and buffering scheme based on movement detection to reduce multimedia data packet loss when an MN move from current subnet to new subnet during handover. It is because IEEE 802.11 did not transfer information of movement detection to AP. In this paper, we proposed new fast handover scheme by using advanced access point and optimized snoop protocol for network based Proxy Mobile IPv6 in IEEE 802.11 Networks. During handover, the proposed scheme reduces both the multimedia data packet loss rate and the packet reordering problems without changing MN's mobility stack in IEEE 802.11 Networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12C
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• pp.971-982
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• 2008

In this paper, we propose a new digital duplexing scheme, called SDD(Synchronous Digital Duplexing), which can increase data efficiency and flexibility of resource by transmitting uplink signal and downlink signal simultaneously. In order to transmit uplink data and downlink data simultaneously, the proposed SDD obtains mutual informations between AP(access point) and each SSs(subscriber station), SS and other SSs by mutual ranging procedure. These informations are used for selection of transmission time, decision of CS insertion, setting of CS length, and FFT duration resetting, etc. It is shown that the proposed SDD is appropriate for duplexing scheme in indoor environments over the conventional TDD(Time Division Duplexing) and FDD(Frequency Division Duplexing).

• Journal of Biomedical Engineering Research
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• v.43 no.4
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• pp.290-297
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• 2022

During surgery, Surgical instruments are often left behind due to accidents. Most of these are surgical gauze, so radioactive non-permeable gauze (X-ray gauze) is used for preventing of accidents which gauze is left in the body. This gauze is divided into wire and pad type. If it is confirmed that the gauze remains in the body, gauze must be detected by radiologist's reading by imaging using a mobile X-ray device. But most of operating rooms are not equipped with a mobile X-ray device, but equipped C-Arm equipment, which is of poorer quality than mobile X-ray equipment and furthermore it takes time to read them. In this study, Use C-Arm equipment to acquire gauze image for detection and Build dataset using artificial intelligence and select a detection model to Assist with the relatively low image quality and the reading of radiology specialists. mAP@50 and detection time are used as indicators for performance evaluation. The result is that two-class gauze detection dataset is more accurate and YOLOv5 model mAP@50 is 93.4% and detection time is 11.7 ms.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06d
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• pp.291-293
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• 2012

급격히 증가하는 모바일 디바이스에 의한 모바일 데이터 요구량을 처리하기 위해 가장많이 고려되고 있는 IEEE 802.11의 WLAN은 셀룰러보다 높은 데이터 전송속도를 제공하지만 이동성이 고려되어있지 않다. 이에 본 논문에서는 Enterprise WLAN에서 IEEE 802.21 MIH 표준에 기반하여 Media Independent Information Server (MIIS)로부터 수신된 주변 AP들의 네트워크의 정보를 바탕으로 후보 엑세스 AP 네트워크를 선정 및 WiMAX에 make-before-break 핸드오버하는 방안을 제안한다. 제안하는 방안은 실제 Enterprise WLAN와 Mobile WiMAX 환경에서 이동하는 단말의 시간에 따른 TCP throughput에 대한 성능평가를 하였다. 이를 통해 제안하는 방안의 평균TCP throughput 성능이 9.04Mbits/s으로 기존 방안의 TCP throughput 성능 6.49Mbits/s보다 약 40%향상됨을 확인하였다.

• 한국정보통신설비학회:학술대회논문집
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• 2009.08a
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• pp.208-210
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• 2009

Currently, Wireless LAN(WLAN) service is widely deployed to provide high speed wireless Internet access through the mobile stations such as notebook and PDA. To provide enhanced security and user access control in the public WLAN area, WLAN access points should have the capability of IEEE 802.1x-based user authentication and authorization functionality. In this paper, we provide a brief understanding of IEEE 802.1x standards and related protocols like EAPOL(Extended Authentication Protocol Over LAN), EAP, RADIUS and describe how the IEEE 802.1x is designed and implemented in our embedded linux-based WLAN AP which is named i-WiNG. (Intelligent Wireless Internet Gateway). For the network security and user authenti -cation purposes, a supplicant who wants to access Internet should be authorized to access the AP port using the EAPOL.

• Proceedings of the Korean Society of Computer Information Conference
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• 2008.06a
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• pp.301-307
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• 2008

모바일 기기가 무선 LAN, 블루투스 등을 지원하면서 언제 어디서나 다양한 네트워크와의 접속은 물론 끊김이 없는 서비스를 요구한다. 이에 사용자의 이동과 물리적 환경의 변화에도 네트워크 접속을 유지할 수 있는 통신 메카니즘과 모바일 장치의 이동성 관리가 중요하다. 본 논문에서는 Personal Area Networking Profile의 BNEP (Bluetooth Networking Encapsulation Protocol)를 사용하여 BAP(블루투스 AP)와 모바일 기기의 LAN 접속은 물론, 이종 네트워크 환경에서 사용자 이동에도 끊김 없는 서비스가 가능하게 하여 블루투스 단말의 인터넷 접근과 IP 이동성을 효율적으로 지원한다. 테스트베드를 구축하여, USB 타입의 블루투스 Dongle을 이용한 AP를 구현하고 이종 네트워크 접속 가능과 네트워크 상황에 따른 이종 네트워크 장치의 적절한 사용을 확인하였다. 이종 네트워크의 핸드오버에 필요한 설정을 미리 실행하여 핸드오버에 발생하는 지연시간과 패킷 손실을 확연히 줄였다.