• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.11A
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• pp.1130-1137
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• 2006

One of the important performance issues in large-scale RFID systems is to resolve collisions among responses from RFID tags. Considering two do facto anti-collision solutions, namely the binary-tree splitting algorithm and the Slotted-Aloha algorithm, we propose to use multi-packet reception (MPR) capability to enhance the RFID tag reading rate (i.e., throughput). MPR allows an RFID reader to receive multiple reponses transmitted by tags at the same time. We analyze the effect of MPR capability in the above anti-collision algorithms, which is also validated by simulation. The analysis and simulation results show that RFID reader antenna design and signal separation techniques play an important role in improving RFID system performance with MPR capability.

• Journal of Environmental Science International
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• v.33 no.2
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• pp.131-138
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• 2024

The effect of magnetite particles on the anaerobic digestion (AD) of furfural wastewater was investigated using sequential anaerobic batch tests. The batch tests with four 500 mL anaerobic bioreactors were performed under two conditions: FC treatment for AD of furfural without magnetite particles, and FM treatment for AD of furfural with magnetite particles. The FC bioreactors showed a decreasing methane production rate (MPR) across the sequential batches, with a final batch MPR of 11.3 ± 0.4 mL CH₄/L/d, indicating the need for a methanogenesis enhancer to achieve high-rate AD of furfural. Conversely, FM bioreactors exhibited significantly higher MPR, exceeding FC values by 4-196%, with a final batch MPR of 33.5 ± 0.1 mL CH₄/L/d, which was about three times higher than FC. Additionally, FM bioreactors had faster degradation rates of furfural, valeric acid, and acetic acid compared to FC, with values exceeding those in PC by 3.0, 1.14, and 2.8 times, respectively. These results demonstrate that magnetite particles can enhance the AD of furfural not only by accelerating methanogenesis but also by accelerating the anaerobic degradation of furfural and its intermediates, such as volatile fatty acids. This study provides valuable insights for developing high-rate AD systems for furfural wastewater treatment.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.255-260
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• 2011

We wanted to evaluate the usefulness of three-dimensional reconstructive images using computed tomography for rib fracture patients. The reconstruction used in clinical multi planar reformation(MPR), volume rendering technique(VRT), and image data using quantitative methods and qualitative methods were compared. Much more, the artifact shadow was minimized to reconstruct with 3D volumetric image by using an law data in the analysis of the reconstructive image and chest CT scan of the evaluation result fractures of the thoracic patient. And we could know that the fractures of the thoracic determination and three dimension volume image reconstruction time were reduced.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.800-811
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• 2018

This paper presents a regenerative braking control scheme for Switched Reluctance Machine (SRM) drive in Electric Vehicles (EVs). The main purpose is to maximize the recovered energy during battery charging by taking into account the nonlinear physical characteristics of the Switched Reluctance Machine. The proposed regenerative braking method employs the back-EMF in the generation process as a complicated position-dependent voltage source. The proposed maximum power recovery (MPR) operation of the regenerative braking is first based on the maximization of the extracted power from the machine and then the maximization of the power transferred to the battery. The maximum power extraction (MPE) from SRM is based on maximizing the energy conversion ratio by the calculation of the optimum PWM switching duty cycle, turn-on, and turn-off angles. By using the impedance matching theorem that allows the maximum power transfer (MPT) of the MPE, the proposed MPR is achieved. The parametric averaged value modeling of the machine phase currents in the chopping control mode is used for MPR realization. By following this model, a nonlinear equivalent input resistance is derived for the battery internal resistance matching. The effectiveness of the proposed regenerative braking method is demonstrated through simulation results and experimental implementation.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.3
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• pp.38-50
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• 2023

Recent advances in artificial intelligence (AI) technology have enabled the integration of AI technology into image sensors, such as Closed-Circuit Television (CCTV), to detect specific traffic incidents. However, most incident detection methods have been carried out using fixed equipment. Therefore, there have been limitations to incident detection for all roadways. Nevertheless, the development of mobile image collection and analysis technology, such as image sensors and edge-computing, is spreading. The purpose of this study is to estimate the reducing effect of the incident detection time according to the introduction level of mobile image collection and analysis equipment (or connected vehicles). To carry out this purpose, we utilized data on the number of incidents collected by the Suwon branch of the Gyeongbu expressway in 2021. The analysis results showed that if the market penetration rate (MPR) of connected vehicles is 4% or higher for two-lane expressway and 3% or higher for three-lane expressways, the incident detection time was less than one minute. Furthermore, if the MPR is 0.4% or higher for two-lane expressways and 0.2% or higher for three-lane expressways, the incident detection time decreased compared to the average incident detection time announced by the Korea Expressway Corporation for both two-lane and three-lane expressways.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.23 no.2
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• pp.157-172
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• 2024

Autonomous driving technology, when commercialized, has the potential to improve the safety, mobility, and environmental performance of transportation networks. However, safe autonomous driving may be hindered by poor sensor performance and limitations in long-distance detection. Therefore, cooperative autonomous driving that can supplement information collected from surrounding vehicles and infrastructure is essential. In addition, since HDVs, AVs, and CAVs have different ranges of perceivable information and different response protocols, countermeasures are needed for mixed traffic that occur during the transition period of autonomous driving technology. There is a lack of research on traffic flow optimization that considers the penetration rate of autonomous vehicles and the different characteristics of each road segment. The objective of this study is to develop weights based on safety, operational, and environmental factors for each infrastructure control use case and autonomous vehicle MPR. To develop an integrated evaluation index, infra-guidance AHP and hybrid AHP weights were combined. Based on the results of this study, it can be used to give right of way to each vehicle to optimize mixed traffic.

• Korean Journal of Digital Imaging in Medicine
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• v.16 no.1
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• pp.13-19
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• 2014

Purpose: FLAIR image is beneficial for the diagnosis of various bran diseases including ischemic CVS, brain tumors and infections. However the border between the legion of brain metastasis and surrounding edema may not be clear. Therefore, this study aims to investigate the practical benefits of delayed imaging by comparing the image from a patient with brain metastasis before a contrast enhancement and the image 10 minutes after a contrast enhancement. Materials and methods: Of the 92 people who underwent MRI brain metastases in suspected patients 13 people in three patients there is no video to target the 37 people confirmed cases, and motion artifacts brain metastases in our hospital June-December 2013, 18 people measurement position except for the three incorrect patient (male: 11 people, female: 7 people, average age: 60 years) in the target, test equipment, 3.0T MR System (ACHIEVA Release, Philips, I was 8ChannelSENSE Head Coil use Best, and the Netherlands). TR 11000 ms, TE 125 ms, TI2800 ms, Slice Thickness 5 mm, gap 5 mm, is a Slice number 21, the parameters of the 3D FFE, T2 FLAIR variable that was used to test, TR 8.1 ms, TE 3.7 ms, Slice number 240 I set to. The experiment was conducted by acquiring the FLAIR prior to contrast enhancement (heretofore referred to as Pre FLAIR), and acquiring the 3D FFE CE five minutes after the contrast enhancement, and recomposing the images in an axial plane of S/T 3mm, G 0mm (heretofore referred to as MPR TRA CE). Using the FLAIR 10 minutes after the contrast enhancement (heretofore referred to as Post FLAIR) and Pi-View, a retrospective study was conducted. Using MRIcro on the image of a patient confirmed for his diagnosis, the images before and after the contrast media, as well as the CNR and SNR of the MPR TRA CE images of the lesion and the site absent of lesion were compared and analyzed using a one-way analysis of variance. Results: CNR for Pre FLAIR and Post FLAIR were 34.35 and 60.13, respectively, with MPR TRA CE at 23.77 showing no significant difference (p<0.050). Post-experiment analysis shows a difference between Pre FLAIR and Post FLAIR in terms of CNR (p<0.050), but no difference in CNR between Post FLAIR and MPR TRA CE (p>0.050), indicating that the contrast media had an effect only on Pre FLAIR and Post FLAIR. The SNR for the normal site Pre FLAIR was 106.43, and for the lesion site 140.79. Post FLAIR for the normal site was 107.79, and for the lesion site 167.91. MPR TRA CE for the normal site was 140.23 and for the lesion site 183.19, showing significant difference (p<0.050), and post-experiment analysis shows that there was a difference in SNR only on the lesion sites for Pre FLAIR and Post FLAIR (p<0.050). There was no difference in SNR between the normal site and lesion site for Post FLAIR and MPR TRA CE, indicating no effect from the contrast media (p>0.050). Conclusions: This experiment shows that Post FLAIR has a higher contrast than Pre FLAIR, and a higher SNR for lesions, It was not not statistically significant and MPR TRA CE but CNR came out high. Inspection of post-contrast which is used in a high magnetic field is frequently used images of 3D T1 but, since the signal of the contrast medium and the blood flow is included, this method can be diagnostic accuracy is reduced, it is believed that when used in combination with Post FLAIR, and that can provide video information added to the diagnosis of brain metastases.

• Journal of The Korean Radiological Technologist Association
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• v.29 no.1
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• pp.193-193
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• 2003

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.07a
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• pp.291-293
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• 2011

ITU와 ISO/IEC가 공동으로 UHD급 영상 부호화를 위해 표준화를 진행하고 있는 HEVC 코덱은 H.264/AVC 대비 2배 이상의 압축 효율을 갖는 것을 목표로 정하고 있다. HEVC 코덱은 다수의 개선된 기술을 사용하고 있기 때문에 부호화효율을 크게 향상시킬 수 있었지만, 다른 한편으로 동작 복잡도가 매우 높기 때문에 여러 가지 다양한 응용 제품에서 활용되기 위해서는 복잡도 문제가 개선되어야 한다. 본 논문에서는 HEVC의 움직임 벡터 예측 시 현재 블록의 주변 블록들이 가지고 있는 참조 영상 정보를 이용하여 움직임 벡터 추정 모듈의 복잡도를 감소시키는 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘을 사용하면, 압축 영상의 화질 저하는 최소화하면서 부호화기의 동작속도를 크게 감소시킬 수 있음을 실험을 통해 알 수 있었다.

• Proceedings of the ESK Conference
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• 1993.10a
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• pp.38-45
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• 1993

VDT는 저주파 대역에서 인체에 해롭다고 여겨지는 전자파를 발생시키고 있다. 선진제국에서는 VDT에 서 발생하는 전자파를 규제하기 위해 VDT 전자파 측정방법의 표준화와 안전 규제 등을 실시하고 있다. VDT와 관련한 대표적인 측정기준으로는 스웨덴의 MPR 기준이 있다. 본 연구에서는 MPR 기준에 의거 VDT의 전기장, 자기장 모두에 대해 거리별, 방향별, 높이별 세기를 측정하였다. 또한 VDT 전자파의 상대적 세기를 알아보기 위해 다른 전기제품인 전기담요, 헤어드리이어 등에 대한 비교측정도 수행하였 으며, 보안경의 전자파 차폐효과도 측정하였다. 측정결과, VDT 전기장은 전면에서 세기가 가장 크며, 후면으로 갈수록 작아지는 것으로 나타났으며, 자기장은 ELF 대역은 양측면에서, VLF 대역은 전면에서 그 크기가 가장 큰것으로 나타났다. 전기제품과의 비교에서는 VDT의 전기장, 자기장은 전기담요, 헤어 드리이어 등에 비해 크지 않은 것으로 나타났으며, 보안경은 접지해서 쓸때만 전기장 차폐효과가 큰것 으로 나타났다.