• Title/Summary/Keyword: frequency-based method

Search Result 6,111, Processing Time 0.05 seconds

An Efficient Object Extraction Scheme for Low Depth-of-Field Images (낮은 피사계 심도 영상에서 관심 물체의 효율적인 추출 방법)

  • Park Jung-Woo;Lee Jae-Ho;Kim Chang-Ick
    • Journal of Korea Multimedia Society
    • /
    • v.9 no.9
    • /
    • pp.1139-1149
    • /
    • 2006
  • This paper describes a novel and efficient algorithm, which extracts focused objects from still images with low depth-of-field (DOF). The algorithm unfolds into four modules. In the first module, a HOS map, in which the spatial distribution of the high-frequency components is represented, is obtained from an input low DOF image [1]. The second module finds OOI candidate by using characteristics of the HOS. Since it is possible to contain some holes in the region, the third module detects and fills them. In order to obtain an OOI, the last module gets rid of background pixels in the OOI candidate. The experimental results show that the proposed method is highly useful in various applications, such as image indexing for content-based retrieval from huge amounts of image database, image analysis for digital cameras, and video analysis for virtual reality, immersive video system, photo-realistic video scene generation and video indexing system.

  • PDF

Study on the Improvement of OFDM/64QAM Modem (OFDM/64QAM방식의 모뎀 설계)

  • Park, Jin-Soo
    • Journal of Advanced Navigation Technology
    • /
    • v.16 no.1
    • /
    • pp.158-162
    • /
    • 2012
  • In this paper, we propose a wireless modem, which used OFDM/64QAM method and the ISM band with 2.4GHz radio frequency. In this paper proposed the case of a modem, the main program to process the baseband processor, processing speed, operating voltage, and reliability should be ensured. So we have designed with Ralink's RT2870, witch was used for Wi-Fi solution. The RT2870 provides full support for wireless LAN standard, and supports various modulation formats, 2.4GHz and 5GHz bands, both of which support chip. In this paper, we also output the modulated signal transmitted wirelessly to the 2.4GHz band RF RT2850 chip processing was applied and using 40MHz band 2.422 ~ 2.462GHz wireless bands were designed to occupy. By applying bi-directional transmission between wireless transmitter and receiver, it can be effectively connected with any kinds of wireless LAN with 2.4GHz ISM band. Therefore it could economically be used as peripheral equipments for POS system or personal wireless device based on Android platform.

Shielding effectiveness of an Aperture in Infinite Conducting plane Due to HEMP Incidence (무한 도체평판 개구에 입사하는 HEMP 파형에 따른 침투 전자파의 차폐효과)

  • Lim, Byoung-Jin;Seo, Hun-Wook;Lim, Sung-Min;Kim, Ki-Chai
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.15 no.8
    • /
    • pp.1647-1652
    • /
    • 2011
  • This paper presents the shielding effectiveness for the IEC 61000-2-9 standard when HEMP source penetrates through an aperture in a planar conducting plane of infinite extent. An integral equation is derived and solved by applying Galerkin's method of moments for calculating the electric shielding effectiveness. The electric shielding effectiveness is examined based on changing the aperture length and width. It is shown that the electric shielding effectiveness is suddenly decreases as the aperture width of 0.4 ~ 0.45${\lambda}$. It is also found that the penetrated electric field for the IEC 61000-2-9 incident field is different from the Bell Laboratory incident field, but the frequency characteristic of the electric shielding effectiveness becomes the same shape.

Characteristics of Nonthermal Plasma Source in Various Liquids

  • Lim, Seung-Ju;Min, Boo-Ki;Taylor, Nathan;Kim, Tae-Gyu;Kim, Hyeong-Seok;Yang, Seon-Pil;Jung, Jin-Yong;Han, Jin-Hyun;Lee, Jong-Yong;Kang, Seung-Oun;Choi, Eun Ha
    • Proceedings of the Korean Vacuum Society Conference
    • /
    • 2014.02a
    • /
    • pp.259.1-259.1
    • /
    • 2014
  • Recently non-thermal plasma has been frequently applied to various research fields. The liquid plasma have received much attention lately because of interests in surgical and nanomaterial synthesis applications. Especially, intensive researches have been carried out for non-thermal plasma in liquid by using various electrode configurations and power supplies. We have developed a bioplasma source which could be used in a liquid, in which outer insulator has been covered onto the outer electrode. Also we have also put an insulator between the inner and outer electrode. Based on the surface discharge mode, the nonthermal bioplasma has been generated inside a liquid by using an alternating current voltage generator with peak voltage of 12 kV under driving frequency of 22 KHz. Here the discharge voltage and current have been measured for electrical characteristics. Especially, We have measured discharge and optical characteristics under various liquids of deionized (DI) water, tap water, and saline by using monochromator. We have also observed nitric oxide (NO), hydrogen peroxide (H2O2), and hydroxyl (OH) radical species by optical emission spectroscopy during the operation of bioplasma discharge inside various kinds of DI water, tap water, and saline. Here the temperature has been kept to be $40^{\circ}C$ or less when discharge in liquid has been operated in this experiment. Also we have measured plasma temperature by high speed camera image and density by using either H-alpha or H-beta Stark broadening method.

  • PDF

Performance Analysis of MC-DS-CDMA System Using a Interference Suppression Method in a Multipath Fading Channel (다중 경로 페이딩 채널 환경에서 다중반송파 DS-CDMA 시스템의 간섭 제거 성능 분석)

  • Park Tae-Yoon;Choi Jae-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.27 no.8B
    • /
    • pp.745-751
    • /
    • 2002
  • The performance of existing CDMA-type multiple access data transmission systems is limited by interferences due to adverse mobile communication channel characteristics. Among them, the multi-user interference becomes one of the major performance degradation factors because the signal-to-signal orthogonality can be easily perturbed when numerous user signals are distorted by multipath fading channels and mixed together. In order to enhance the performance of CDMA-type systems by suppressing the multi-user interference, we have adopted chip-based cyclic prefix insertion along with adaptive one-tap DFE equalization into MC-DS-CDMA, which is known for its robustness in the frequency selective multipath fading channel environment. In order to assess the performance of the proposed system, a set of computer simulations is performed in the reverse link in which each user signal undergoes different multipath Rayleigh fading. The results show us a superior performance of our system over other CDMA systems in terms of SNR to BER measurements.

Enhanced High Contrast Image Rendering Method Using Visual Properties for Sharpness Perception (시각 선명도 감각 특성을 이용한 개선된 고명암 대비 영상 렌더링 기법)

  • Lee, Geun-Young;Lee, Sung-Hak;Kwon, Hyuk-Ju;Sohng, Kyu-Ik
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.38A no.8
    • /
    • pp.669-679
    • /
    • 2013
  • When an image is converted from HDR (high dynamic range) to LDR (low dynamic range), a tone mapping process is the essential component. Many TMOs (tone mapping operators) have been motivated by human vision which has lower physical luminance range than that in real scene. The representative of human vision properties which motivate TMOs is the local adaptation. However, TMOs are ultimately compressing image information such as contrast, saturation, etc. and the compression causes defects in image quality. In this paper, in order to compensate the degradation of the image which is caused by TMOs, the visual acuity-based edge stop function is proposed for applying the property of human vision to base-detail separation. In addition, using CSF (contrast sensitivity function) which represents the relationship among spatial frequency, contrast sensitivity, and luminance, the sharpness filter is designed and adaptively applied to the detail layer in regard to surround luminance.

Diabetes Risk Analysis Model with Personalized Food Intake Preference (개인 식품섭취 선호도에 따른 당뇨병 발생 위험도 분석 모델)

  • Jeon, So-Hye;Kim, Nam-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.14 no.11
    • /
    • pp.5771-5777
    • /
    • 2013
  • The need of continuous management for diseases came to the fore as a chronic disease has increased, however, research related to personalized food intake analysis are insufficient. In diabetes risk analysis model of this study, food preferences are calculated by Pearson correlation coefficient that is proven method to assess the similarity, and diabetes risk is computed as a Logistic regression that was used in prevalence studies. For the Significance evaluation of this model, it was verified through t-test at 0.05 level of 52 comparison subjects and 52 control subjects. Both groups were significantly independent (p=0.046 <0.05). This model is a new way to personalized health management, through the application to healthcare system based on web and mobile.

A Study on Analysis of User Behavior and Needs for Efficient Use of a Home Smart Mirror (홈 스마트 미러의 효율적 활용을 위한 사용자 행태 및 니즈 분석 연구)

  • Oh, Moonseok
    • Journal of Korea Society of Digital Industry and Information Management
    • /
    • v.12 no.1
    • /
    • pp.119-129
    • /
    • 2016
  • Rapid changes to the paradigm of smart media have created a communication environment through merging with various media such as IoT technology, which is internet of things. Among them, user' need for a start home, which is one of people living conditions, has been growing and values of the communication environment in a living space using a smart mirror have been growing. However, studies on figuring out behavior and analyzing needs of family members who actually use the living space are insufficient. This study is to draw the service system of the home smart mirror by analysis of behavior and needs of users of the living space. For a research method for analysis of behavior of family members, I wrote two kinds of user's experience maps, which are frequency of use of a quantitative space of a living space and space's important value scales by persona study and depth interview. Through this, applied spaces of the home smart mirror (living room, bathroom, powder room, dress room, porch, kitchen, room) and the types of user needs (type of providing information, entertainment type, control type, service type) have been drawn and statistical analysis methodology has been utilized for a research of user preferences in regard to correlation between living spaces and types of user needs based on a survey. As a result of analysis of ages and gender, types of user needs by space have been drawn and the service system of the home smart mirror has been drawn. It would be utilized as a basic material for various contents development and design using the smart mirror in the future.

Recovery Efficiency of Cumulus Oocyte Complexes (COCs) according to Collection Frequency for Ovum Pick-up (OPU) Method in Hanwoo Cow

  • Kang, Sung-Sik;Kim, Ui-Hyung;Lee, Seok-Dong;Lee, Myung-Suk;Han, Man-Hye;Cho, Sang-Rae
    • Journal of Animal Reproduction and Biotechnology
    • /
    • v.34 no.4
    • /
    • pp.300-304
    • /
    • 2019
  • This study was conducted to examine the oocyte recovery efficiency through having an OPU session once and twice a week. Also, the oocyte recovery efficiency was examined by using OPU after two and three months of rest period. Six cows were used for oocytes collection and were randomly divided into two groups. In experiment 1, OPU sessions were conducted once and twice a week to collect oocytes. The collected oocytes between once and twice OPU groups were classified into four groups (grade 1, 2, 3 and 4) according to the quality of cumulus cells and ooplasm. Based on the result, the percentage of collected oocytes per aspirated follicle number was similar between once and twice OPU session groups (65.5 ± 1.9 and 68.7 ± 1.4 vs.). However, the percentage of grade 1 oocytes from the twice OPU session group was significantly high compared with that of the once a week OPU session group (25.3 ± 0.9 and 32.5 ± 1.2% vs. once and twice session group, respectively, p < 0.05). In experiment 2, the group with three months of rest period tended to have a high percentage of collected oocyte compared with the group with two months of rest period (64.6 and 70.9% vs. 2 and 3 months rest group, respectively, p = 0.62). The percentage of grade 4 in the group with three months of rest period was significantly low compared with the group with two months of rest period group (27.3 and 36.5% vs. two and three months rest group, respectively, p = 0.05). In conclusion, twice a week OPU session is suitable for collection of high quality oocytes by using OPU, and three months of rest period is needed for the recovery of oocyte quality of a donor cow.

A Study on Aircraft Sensitivity Analysis for C.G Variation of Longitudinal Axis (항공기 세로축 무게중심의 변화에 따른 민감도 해석에 관한 연구)

  • 김종섭
    • Journal of the Korean Society for Aeronautical & Space Sciences
    • /
    • v.34 no.6
    • /
    • pp.83-91
    • /
    • 2006
  • An advanced method of Relaxed Static Stability (RSS) is utilized for improving the aerodynamic performance of modern version supersonic jet fighter aircraft. The flight control system utilizes RSS criteria in longitudinal axis to achieve performance enhancements and improve stability. The flight control law of T-50 advanced trainer employs RSS concept in order to improve the aerodynamic performance and guarantee aircraft stability. The longitudinal center of gravity(X-c.g) varies as a function of external stores, fuel state and gear position. Shifts in X-c.g relate directly to longitudinal static margin in aircraft stability. This paper deals the maximum aft X-c.g for critical aircraft loadings and checks static margin limits using sensitivity such as damping, natural frequency, gain and phase margin. And nonlinear analysis was conducted for such as short period input. And also, this paper shows the T-50 aircraft stability based on the result of high angle of attack flight such as upright and inverted departure.