• Title/Summary/Keyword: Ghost phenomenon

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A Study on Locational Control of Motion Ghost in Magnetic Imaging System (자기공명영상장치(磁氣共鳴映像裝置)에서 움직임허상(虛像)의 위치제어(位置制御)에 관(關)한 연구(硏究))

  • Lee, Who-Min
    • Journal of radiological science and technology
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    • v.16 no.2
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    • pp.19-26
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    • 1993
  • Magnetic Resonance Image represents three-dimensional diagnostic imaging technique using both nuclear magnetic resonance phenomenon and computer. Compared with computed tomography (CT), MRI have advantages harmless to patient's body, three-dimensional image with high resolution and disadvantages long data acquisition time because of long T1 relaxation time, relatively low signal to noise ratio, high cost of setting, also. As physiologic motion of tissue results in motion ghost in MRI, high 2.0Tesla make improve low signal to noise ratio. This study have aim to improve image quality with controling motion ghost of tissue. Supposing a moving pixel in constant frequency, one pixel make two ghosts which are same size and different anti-phase. So, this study will show adjust parameter on locational control of motion ghost. Author made moving phantom replaced by respiratory movement of human, researched change of motion frequency, FOV by location shift, and them decided optimal FOV (field of view). The results are as follows: 1. The frequency content of the motion determines how far the image always appear in phase-encoding direction, the morphology of the ghost image is characteristic of the direction of the motion and its amplitude. 2. Double FOV of fixed signal object for locational control of motion ghost is recommended. Decreasement of spatial resolution by increasing FOV can compensate on increasing of matrix in spite of scan time increasement.

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CKGS: A Way Of Compressed Key Guessing Space to Reduce Ghost Peaks

  • Li, Di;Li, Lang;Ou, Yu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.16 no.3
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    • pp.1047-1062
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    • 2022
  • Differential power analysis (DPA) is disturbed by ghost peaks. There is a phenomenon that the mean absolute difference (MAD) value of the wrong key is higher than the correct key. We propose a compressed key guessing space (CKGS) scheme to solve this problem and analyze the AES algorithm. The DPA based on this scheme is named CKGS-DPA. Unlike traditional DPA, the CKGS-DPA uses two power leakage points for a combined attack. The first power leakage point is used to determine the key candidate interval, and the second is used for the final attack. First, we study the law of MAD values distribution when the attack point is AddRoundKey and explain why this point is not suitable for DPA. According to this law, we modify the selection function to change the distribution of MAD values. Then a key-related value screening algorithm is proposed to obtain key information. Finally, we construct two key candidate intervals of size 16 and reduce the key guessing space of the SubBytes attack from 256 to 32. Simulation experimental results show that CKGS-DPA reduces the power traces demand by 25% compared with DPA. Experiments performed on the ASCAD dataset show that CKGS-DPA reduces the power traces demand by at least 41% compared with DPA.

Study on Simulation Method for Combustion Flow Field with the Moving Boundary of Solid Propellants (이동 경계면을 가진 고체 추진제 연소 유동장의 해석 기법 연구)

  • Sung, Hyung-Gun;Park, Sol;Hong, Gi-Cheol;Roh, Tae-Seong;Choi, Dong-Whan
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.229-232
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    • 2007
  • A numerical method for the moving boundary required in analysis of the combustion phenomenon of the solid propellant has been studied. The ghost cell extrapolation has been used in the Eulerian coordinate system. The Lagrangian method has been used in Non-Eulerian coordinate system. Results of the numerical analysis were verified by comparing to theoretical results of 1-D free-moving piston in the pipe.

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The aspect and meaning of the digital world view in the anime based on myth (신화를 소재로 한 애니메이션 <고스트 메신저>에 나타난 디지털 세계관의 양상과 의미)

  • Kim, Jin-Chul
    • Cartoon and Animation Studies
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    • s.49
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    • pp.299-323
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    • 2017
  • Interests to cultural prototype as a material of cultural contents are getting more increasing nowadays. One of them is myth. The important thing when you are dealing with the myth as the material that how to convert prototype narratives. Today, digital culture is becoming one of the essential elements of mankind, that is a new sociocultural phenomenon and distinguishing differentiation from the past analogue era. In this regard, the combination of mythology and digital culture is effective strategies for transforming storytelling that can resonate with people who are not familiar with myths. puts the view both of this world and underworld, mythical characters, and various elements of the Grim Reaper into the story. And combines them with digital elements. sets the world that the transcendental soul exists as physically transferred data form. and reinterprets the traditional mythology world into the digitally operated world. Soul-Phone from this anime reflects the digital culture such as storage and transmission, and helps enjoying audiences accept the unfamiliar world of myth. And also It symbolically shows dystopian viewpoints through side effects can caused by digital technology development, such as the instrumentalization of human being, the risk of communication through digital media, and ego-loss caused by duplication, etc. In conclusion, forms a consensus with the audience through the transformation strategy of storytelling that converts the world of myth into the digital world. And it reflects the dystopian view and shows a differentiated world view from the narrative of myth.

A Study on Multiple Target Tracking Using Adaptive Neural Network and Mosaic Background Extraction (모자이크 배경이미지 추출과 적응적 신경망을 이용한 다중 보행자 추적 시스템에 관한 연구)

  • 서창진;양황규
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.8
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    • pp.1802-1808
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    • 2003
  • In this paper, we propose a method about the extraction of the pedestrian tracking trajectory in the road and we used the method of mosaic background extraction and adaptive neural network for automatic pedestrian tracking system. We used mosaic background extraction to overcome ghost phenomenon. And we detected pedestrian using differential image analysis. We used adaptive neural network for multiple pedestrian tracking that non­rigid form moving. The ART2 network is capable of detecting the mass­centers of moving objects within one frame. The history of neurons positions in the sequential frames approximates the traces of the targets. The experiments done with the network in simulated environment show promising results.

Inverse Synthetic Aperture Radar Imaging Using Stepped Chirp Waveform (계단 첩 파형(Stepped Chirp Waveform)을 이용한 ISAR 영상 형성)

  • Lee, Seong-Hyeon;Kang, Min-Suk;Park, Sang-Hong;Shin, Seung-Yong;Yang, Eunjung;Kim, Kyung-Tae
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.25 no.9
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    • pp.930-937
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    • 2014
  • Inverse synthetic aperture radar (ISAR) images can be generated by radar which radiates the electromagnetic wave to a target and receives signal reflected from the target. ISAR images can be widely used to target detection and recognition. This paper proposed a method of generation of high resolution ISAR images by synthesizing frequency spectrums of each stepped chirp waveform in one burst and sub-sampling in frequency domain. This process is performed over entire bursts during coherent processing interval. Conventional ISAR image generation method using stepped frequency waveform has a severe problem of short unambiguous range, loading to ghost phenomenon. However, this problem can be resolved by the proposed method. In simulations, we generate high resolution ISAR image of the moving target which is Boeing-737 aircraft model composed of several ideal point scatterers.

A Study on the FIR Digital Filter using Modified Window Function (변형된 창함수를 사용한 FIR 디지털 필터에 관한 연구)

  • 강경덕;배상범;김남호;류지구
    • Journal of the Institute of Convergence Signal Processing
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    • v.4 no.1
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    • pp.49-55
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    • 2003
  • The use of digital filters in the signal process field is increasing rapidly with development of the modern industrial society. Especially, detail processors, Y/C separators, ghost removing filters, standard converters (NTSC to PAL or PAL to NTSC) and noise reducers, all of which use digital filters, tend to be used in digital video and audio processing, CATV and various communication fields. Generally, there are two different digital filters, the Rf (infinite impulse response) filter and the FIR (finite impulse response) filter in digital filter. In this paper, we have designed FIR filter which has the phase linearity and the easiness of creation. In the design of the FIR digital filter, the window function is used to alleviate the ripples caused by Gibbs Phenomenon around the cut off frequency of the band pass. But there're some problems to choose proper window function for the design destination due to its fixed values. Therefore, in this paper, we designed a modified Hanning window with new parameter which is adaptively chosen corresponding to design objectives. The digital filter was simulated to prove the validity of the model and it was compared with the Hamming, the Manning, the Blacknan and the Kaiser window function. And we have used peak side-lobe and transient characteristics as standard of judgement.

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Agent "M" -The Apparatus of "Hate" and Human or Non-Human Beings as Living Dead (Agent "M" -'혐오'의 장치와 리빙 데드의 (비)인간)

  • Kwon, Doo-Hyun
    • Journal of Popular Narrative
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    • v.27 no.1
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    • pp.133-185
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    • 2021
  • This study is an attempt to connect television drama M, which deals with abortion issues, with theoretical focus such as materiality, relativity, and agency, to understand diffractively as an cartography of agential reality. According to Karen Barard's Agential Realism, Television drama M is a sociocultural phenomenon produced by the agential intra-actions of material-discursive apparatuses such as medical technology, ghost stories and legends, and male-affect. The 1990s repeatedly revealed "hate" through apparatuses such as technology, discourse, and affect, which are directed at women's gendered bodies. The material -discursive practice of plastic surgery and abortion proves that the agential reality surrounding the body is closely intertwined with medical technology, as well as with the genderized hate. Another related material-discursive phenomenon is rediscovery of the legend and fad of the ghost story, which is also produced from the hate of the denaturalized body, which is once again expanded and reproduced. Appearing in this environment of affect, M enacts diffraction, which is based on backlash, lacking posthuman implications for the materialization of the techno-body. M puts humanistic assumptions about "Man" as a universal definition, historically framed and defined in context. But it is not universal and it is gendered. The current time when the political turmoil surrounding medical technology, discourse, and bodily matters is violently intra-acted is the time to carefully account and respond to the alternative definitions of human beings that M has rejected.

Antimicrobial Effect of Grapefruit Seed Extract on Vibrio parahaemolyticus Isolated from the Southern Adjacent Sea of Korea (남해안연안에 분포되어 있는 Vibrio Parahaemolyticus의 성상 및 Grapefruit Seed Extract 처리에 의한 향균효과)

  • 조성환;강동훈;전상수;정덕화
    • Journal of Food Hygiene and Safety
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    • v.9 no.3
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    • pp.141-149
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    • 1994
  • To investigate the distribution of Vibrio parahaemopyticus in the southern 4 coastal areas, Vibrio parahaemolyticus was isolated from seawater, shellfish and sediment from May to October in 1991, and antimicrobial effect of grapefruit seed extract (GFSE) on the growth of isolated strains were examined. In the 120 sample from 4 coastal areas, 16 strains of Vibrio parahaemolyticus were isolated and identified. The distribution serotype of isolated strains was 10 types of monovalent k-antiserum. Especially k-5 and k-28 were highly distribyted with 3 and 4 strains. 31.3% of isolated strains showed positive on Kanagawa phenomenon test. All isolated Vibrio parahaemolyticus were sensitive to chloramphenicol and gentamycin, 5 and 6 strains were resistant to streptomycin and colistin, respectively. Isolated strains were compared with geographical, month and sample. The distribution of 16 isolated Vibrio parahamolyticus was high at Hadong with 50%(8 strains), on July with 43.8%(7 strains) and from seawater with 37.5%(6 strains) respectively. Minimal inhibitory level of GFSE to Vibrio parahaemolyticus was 50 ppm. With 100 ppm treatment of GFSE, the destroy of cell membrane function, outflow of cell ingredients and ghost morphology of cell were investigated.

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Development of a Large Quantity of Inputs Interface System Using a Single Chip microcontroller (원칩 마이컴을 이용한 대용량 입력 인터페이스 시스템의 개발)

  • Park, Ju-Tae;Choi, Duck-sung;Jeong, Seung-Hyun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.20 no.1
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    • pp.215-221
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    • 2016
  • In this thesis we introduce a large quantity of input interface system using a low cost single chip microcontroller which is consists of walking board with 1600 switches, RS485 communication for switch data communication and PC application software for walking pattern analysis. When a pedestrian walks on the walking board, the pattern analysis of foot pressed switches can be utilized on diverse divisions of sports and industry such as walking physical therapy, dancing, a large quantity of sensors interface system, etc.