• Title/Summary/Keyword: M2M architecture

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Design of an Efficient Initial Frequency Estimator based on Data-Aided algorithm for DVB-S2 system (데이터 도움 방식의 효율적인 디지털 위성 방송 초기 주파수 추정회로 설계)

  • Park, Jang-Woong;SunWoo, Myung-Hoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.3A
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    • pp.265-271
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    • 2009
  • This paper proposes an efficient initial frequency estimator for Digital Video Broadcasting-Second Generation (DVB-S2). The initial frequency offset of the DVB-S2 is around ${\pm}5MHz$, which corresponds to 20% of the symbol rate at 25Msps. To estimate a large initial frequency offset, the algorithm which call provide a large estimation range is required. Through the analysis of the data-aided (DA) algorithms, we find that the Mengali and Moreli (M&M) algorithm can estimate a large initial frequency offset at low SNR. Since the existing frequency estimator based on M&M algorithm has a high hardware complexity, we propose the methods to reduce the hardware complexity of the initial frequency estimator. This can be achieved by reducing the number of autocorrelators and arctangents. The proposed architecture can reduce the hardware complexity about 64.5% compared to the existing frequency estimator and has been thoroughly verified on the Xilinx Virtex II FPGA board.

Dynamics of Forest Community Structure at the Valley of Piagol and Daeseonggol in the Jirisan National Park(I) (지리산국립공원 피아골과 대성골 지역의 산림군집구조 동태(I))

  • Oh, Koo-Kyoon;Kim, Yong-Shik;Oh, Jang-Guen;Ki, Young-Bum
    • Korean Journal of Environment and Ecology
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    • v.22 no.5
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    • pp.514-520
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    • 2008
  • The permanent monitoring plots were installed in 2001 for long-term monitoring the structure of forest communities at the Piagol(Valley) and Daeseonggol(Valley) in the Jirisan National Park, and monitored the forest structure in the studied sites in 2001 and 2006. Dominant species at Piagol and Daeseonggol was Carpinuslaxiflora and Quercus mongolica respectively. Based on the distribution of major species' stem diameter, the species diversity index was higher in Piagol than that of Daeseonggol. The distribution of diameter in major tree species in the studied sites showed a stable plant community structure. The forest of Piagol, which is positioned in the valley, showed a quite a different composition of species from that of Daeseonggol, which is positioned on the slope. In the last five years, the overall grows rate of Piagol Forest decreased by $6.4m^2$ per hectare, while Daeseonggol Forest increased by about $8.27m^2$ per hectare. I think that this is because of the fact that a lot of large old trees have died.

A Low Power Single-End IR-UWB CMOS Receiver for 3~5 GHz Band Application (3~5 GHz 광대역 저전력 Single-Ended IR-UWB CMOS 수신기)

  • Ha, Min-Cheol;Park, Byung-Jun;Park, Young-Jin;Eo, Yun-Seong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.20 no.7
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    • pp.657-663
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    • 2009
  • A fully integrated single ended IR-UWB receiver is implemented using 0.18 ${\mu}m$ CMOS technology. The UWB receiver adopts the non-coherent architecture, which simplifies the RF architecture and reduces power consumption. The receiver consists of single-ended 2-stage LNAs, S2D, envelope detector, VGA, and comparator. The measured results show that sensitivity is -80.8 dBm at 1 Mbps and BER of $10^{-3}$. The receiver uses no external balun and the chip size is only $1.8{\times}0.9$ mm. The consumed current is very low with 13 mA at 1.8 V supply and the energy per bit performance is 23.4 nJ/bit.

Effects of Mixed Seeding of Main Revegetation Plants Treated with Different Seeding Amounts of Pennisetum alopecuroides on Cut-Slope Revegetation (수크령 파종량에 따른 주요녹화식물의 혼파가 비탈면 녹화에 미치는 영향)

  • Ham, Kyung-Sik;Shim, Sang-Ryul
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.18 no.1
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    • pp.25-35
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    • 2015
  • Pennisetum aloperculoides is a key revegetation species mixed with other plants species and used for revegetating cut-slopes. The purpose of this research is to identify the effects of mixed seeding of revegetation plants on cut-slope revegetation with respect to the quantity of Pennisetum aloperculoides seeds. The coverage ratio and appearance frequency of Pennisetum aloperculoides, and other revegetation species were measured to assess the cut-slope revegetation. We divided Pennisetum treatments into four groups with different Pennisetum seed quantities of $0g/m^2$, $5g/m^2$, $10g/m^2$, and $15g/m^2$. For each treatment group, we mixed identical quantities of seeds from herbaceous flowers (bird's-boot trefoil, aster, chrysanthemums, golden coreopsis and china pink), cool-season turfgrasses, and woody plants (korean lespedeza, indigo and silk tree). The increase in the quantity of the Pennisetum seeds resulted in the higher coverage ratio for Pennisetum, but in the lower coverage ratio for herbaceous flowers, cool-season turfgrasses, and woody plants. We observed a short-term succession process in which the dominant species shifted in the following order: the initial species Pennisetum, herbaceous flowers, and then lastly woody plants. In case of the appearance frequency, we also observed the higher appearance frequency for Pennisetum and the lower appearance frequency for the other plants due to the increase in the quantity of Pennisetum seeds. Pennisetum, bird's-foot trefoil and china pink showed the tendency to decrease the appearance frequency from one month after seeding while cool-season turfgrasses became extinct due to summer drought. In the woody plants, the appearance frequencies of korean lespedeza and indigo were high due to the decrease in quantity of Pennisetum seeds. The silk trees were damaged from winter frost and none emerged at all in 2013 (the following year after the seeding). Korean lespedeza and indigo appeared to have the short-term rapid dominance over other treated revegetation plants.

Phytosociological Studios on Natural Vegetation in Hoo-Won, Changduk Palace (창경궁 후원 자연식생의 식물사회학적 연구)

  • 오구균;이경재
    • Journal of the Korean Institute of Landscape Architecture
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    • v.14 no.2
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    • pp.27-42
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    • 1986
  • The vegetation structure in the Hoo - Won, Changduk Palace in Seoul was analysed on 10 sites sampled for understanding structure of natural vegetation. The main vegetational survey was conducted during July, 1985 and actual vegetaion and degree of natural vegetaion types were surveyed additionally. The result summarized of this research are as follows. 1) The physical - chemical conditions of soil showed middle class. This might be derived by short succession period from Pine forest to decidious broadleaf forest and artificial impact by human intervention. 2) When considering dominance species by crown story, Quercus aliena was a dominant species over all site and Castanea crenata, Prunus sargentii and Quercus variabilis appeared as a dominant species locally at upper story. Styrax story and Rhododendron mucronulatum, Styrax japonica, Stephanandra incisa and Lespedeza spp. at lower story. 3) The distances kept by trees per crown story are as follows. The mean distances between trees were 4.5-5.5m at upper story, 2.8-3.3m at middle story. On the other hand, the mean distances between dominant species were 6-8m at upper story, 5-9m at middle story. 4) The vegetation in this area was not developed yet into dominant species community according to the similarity analysis. The natural vegetation was dominated by Quercus spp. especially Quercus aliena according to the analysis of species diversity, relative dominance by story and DBH class. On the orther hand, succession to climax stage dominated by shade tolerent species will take a long time due to little appearance of shade tolerence species by previous heavy artificial impacts on understory species. 5) Quercus forest took possesion of 71.3%(27.37ha) of total forest area when considering the actual vegetation and especially Quercus aliena community covered 53.2%(15.21ha). Carpinus laxiflora community, one of the climax species in temperate zone, took possesion of 1.0%(0.3ha) and Pine densiflora was almost disappeared due to species competition. 6) According to the degree of natural vegetation types, the possession of degree of 6-9 was 60.6% and degree of 7-8, substitute vegetation, was 15.5%. The possesion of degree of 9 which consists of over 50 years old trees simliar to natural vegetaion was the highest, 43.1% in this area. Therefore continuous protection in this area of degree of 9 should be recommended.

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A Study on Chloride Attack Resistibility of Quaternary Concrete (4성분계 콘크리트의 염해 저항성능에 관한 연구)

  • Lee, Dong-Un;Park, Hyun-Jung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.2
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    • pp.1188-1194
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    • 2014
  • The purpose of this study is to estimate Chloride Attack Resistibility and mechanical properties of quaternary concrete adding fly ash, blast-furnace slag, and silica fume. Compressive strength, modulus of elasticity, chloride migration coefficient, charge passed from Rapid chloride penetration test(RCPT), and immersion testing in 3% NaCl are tested. Chloride migration coefficient and charge passed of quaternary concrete measured $0.032{\times}10^{-12}m^2/sec$ and 650 coulomb at 17 weeks, which are in a permitted limit. Also in immersion test, depth of chloride penetration and maximum chloride ion of quaternary concrete measured 3.7 mm and $10.211kg/m^3$ respectively. From the results, quaternary concrete adding fly ash, blast-furnace slag, and silica fume denotes improvement of mechanical properties and chloride attack resistibility.

A 1.248 Gb/s - 2.918 Gb/s Low-Power Receiver for MIPI-DigRF M-PHY with a Fast Settling Fully Digital Frequency Detection Loop in 0.11 ㎛ CMOS

  • Kim, Sang-Yun;Lee, Juri;Park, Hyung-Gu;Pu, Young Gun;Lee, Jae Yong;Lee, Kang-Yoon
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.4
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    • pp.506-517
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    • 2015
  • This paper presents a 1.248 Gb/s - 2.918 Gb/s low-power receiver MIPI-DigRF M-PHY with a fully digital frequency detection loop. MIPI-DigRF M-PHY should be operated in a very short training time which is $0.01{\mu}s$ the for HS-G2B mode. Because of this short SYNC pattern, clock and data recovery (CDR) should have extremely fast locking time. Thus, the quarter rate CDR with a fully digital frequency detection loop is proposed to implement a fast phase tracking loop. Also, a low power CDR architecture, deserializer and voltage controlled oscillator (VCO) are proposed to meet the low power requirement of MIPI-DigRF M-PHY. This chip is fabricated using a $0.11{\mu}m$ CMOS process, and the die area is $600{\mu}m{\times}250{\mu}m$. The power consumption of the receiver is 16 mW from the supply voltage of 1.1 V. The measured lock time of the CDR is less than 20 ns. The measured rms and peak jitter are $35.24ps_{p-p}$ and $4.25ps_{rms}$ respectively for HS-G2 mode.

Parking Lot Vehicle Counting Using a Deep Convolutional Neural Network (Deep Convolutional Neural Network를 이용한 주차장 차량 계수 시스템)

  • Lim, Kuoy Suong;Kwon, Jang woo
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.17 no.5
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    • pp.173-187
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    • 2018
  • This paper proposes a computer vision and deep learning-based technique for surveillance camera system for vehicle counting as one part of parking lot management system. We applied the You Only Look Once version 2 (YOLOv2) detector and come up with a deep convolutional neural network (CNN) based on YOLOv2 with a different architecture and two models. The effectiveness of the proposed architecture is illustrated using a publicly available Udacity's self-driving-car datasets. After training and testing, our proposed architecture with new models is able to obtain 64.30% mean average precision which is a better performance compare to the original architecture (YOLOv2) that achieved only 47.89% mean average precision on the detection of car, truck, and pedestrian.

Wave Boundary Layer: Parameterization Technique and Its Proof

  • Belevich, M.;Safray, A.;Lee, Kwi-Joo;Kim, Kyoung-Hwa
    • Journal of Ocean Engineering and Technology
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    • v.16 no.2
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    • pp.10-20
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    • 2002
  • 본 논문에서는 바다의 자유표면에서 생성되는 항력에 대한 물리적 특성에 대한 연구가 기술되었다. 2차원 파장(Wave Field) 매개변수해석기법(Parametric Analyzing Technique)을 근거로 한 파경계층(Wave Boundary Layer : WBL)의 1차원 모델로서 항력계산과 파경계층의 특성을 추정하였으며 이론의 간략화(Simplifying)에 대한 연구에 주력하였다.

Seismic assessment of existing r.c. framed structures with in-plan irregularity by nonlinear static methods

  • Bosco, Melina;Ferrara, Giovanna A.F.;Ghersi, Aurelio;Marinoc, Edoardo M.;Rossi, Pier Paolo
    • Earthquakes and Structures
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    • v.8 no.2
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    • pp.401-422
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    • 2015
  • This paper evaluates the effectiveness of three nonlinear static methods for the prediction of the dynamic response of in-plan irregular buildings. The methods considered are the method suggested in Eurocode 8, a method previously proposed by some of the authors and based on corrective eccentricities and a new method in which two pushover analyses are considered, one with lateral forces applied to the centres of mass of the floors and the other with only translational response. The numerical analyses are carried out on a set of refined models of reinforced concrete framed buildings. The response predicted by the nonlinear static analyses is compared to that provided by nonlinear dynamic analyses. The effectiveness of the nonlinear static methods is evaluated in terms of absolute and interstorey displacements.