• Title/Summary/Keyword: Standard Density of point

Search Result 71, Processing Time 0.024 seconds

A Study on Technical Trend of Fire Safety on Railway Vehicles for Launch CEN/TS 45545 (CEN/TS 45545 출범에 따른 철도차량 화재안전 기술 동향에 대한 연구)

  • Sung, Si-Young;Woo, Yee-Wan;Park, Jea-Hong
    • Proceedings of the KSR Conference
    • /
    • 2010.06a
    • /
    • pp.1768-1773
    • /
    • 2010
  • CEN/TS 45545 is Europe consolidation standard for fire safety on railway behicles. This is based on the International Union of Railways(UIC) and different European countries. It is intended to protect passengers and staff in railway in the event of a fire on board. It will be prepared in 2012. Based on this consolidate standard, they are going to make single market, for raising technical competitiveness, technical innovation and globalization of that standard. For this reason, European academies, manufacturers, and sub-manufacturers confer and stady animated about CEN/TS 45545. In Korea, get out the safety assessment for ues incombustible interior material, the needs of quantitative analysis on fire protection, demand on recognition of fire protection scenario, and define about fire load analysis are becomin more and more important. Therefore, this paper will estimate and compare Flammability, Smoke Density, Toxicity Index( this is the key point for appraised fire safety performance of material) between CEN/TS45545 and fire standards on railway vehicle. Then suggest criteria for fire safety on railway vehicles.

  • PDF

Detecting the Baryon Acoustic Oscillations in the N-point Spatial Statistics of SDSS Galaxies

  • Hwang, Se Yeon;Kim, Sumi;Sabiu, Cristiano G.;Park, In Kyu
    • The Bulletin of The Korean Astronomical Society
    • /
    • v.46 no.2
    • /
    • pp.72.3-73
    • /
    • 2021
  • Baryon Acoustic Oscillations (BAO) are caused by acoustic density waves in the early universe and act as a standard ruler in the clustering pattern of galaxies in the late Universe. Measuring the BAO feature in the 2-point correlation function of a sample of galaxies allows us to estimate cosmological distances to the galaxies mean redshift, , which is important for testing and constraining the cosmology model. The BAO feature is also expected to appear in the higher order statistics. In this work we measure the generalized spatial N-point point correlation functions up to 4th order. We made measurements of the 2, 3, and 4-point correlation functions in the SDSS-III DR12 CMASS data, comprising of 777,202 galaxies. The errors and covariances matrices were estimated from 500 mock catalogues. We created a theoretical model for these statistics by measuring the N-point functions in halo catalogues produced by the approximate Lagrangian perturbation theory based simulation code, PINOCCHIO. We created simulations using initial conditions with and without the BAO feature. We find that the BAO is detected to high significance up to the 4-point correlation function.

  • PDF

A Study on Air Pollution in Indoor Gymnasiums (실내체육관에서의 공기오염에 관한 연구)

  • 윤승욱;김윤신;이종대;이철민;조용성
    • Journal of Environmental Health Sciences
    • /
    • v.26 no.3
    • /
    • pp.32-37
    • /
    • 2000
  • Nowadays, a new word called SBS(sick building syndrome) has been come into existence. At the point of time when an interest about indoor air pollution and, according to this, countermeasure plan are internationally. Moreover institutional countermeasure should be attended at national level since indoor air quality in public places where many people gather is directly connected with national health. Especially indoor pollution of indoor stadia where all sorts of sports are held can give rise to every kinds of respiratory ailments to players as well as audiences. So it is presented as a main factor that indoor space of stadia is crowded with players and audiences compared with other kinds of indoor space. Therefore, in this research to analyze pollution degree of indoor circumstance for gymnasium and exercising room of folk wrestling. basketball, judo, wrestling, hapkido, swordsmanship and boxing making indoor gymnasium and exercising room an object, when 7 items were measures such as thermocircumstance(temperature, relative humidity, air current, intensity of illumination), dust, carbon monoxide, and carbon dioxide being based on the indoor environmental standard of the first clause of Article 45 of public utilization service which is showed at public hygiene of the Ministry of Health and Social Affairs, it was showed that indoor temperature, relative humidity, air current and intensity of illumination were over standard amount at the most of folk wrestling gymnasium and exercising room. Indoor density of carbon monoxide was preserved to the extent of standard amount (10ppm) at all gymnasiums but carbon dioxide was not in excess of standard amount(1,000 ppm) at most of gymnasiums. Indoor density of dust induced from respiration exceeded the standard amount (150 $\mu\textrm{g}$/㎥) at all gymnasiums of the folk wrestling. Since the folk wrestling players and participants feel physical subjective symptom seriously, in other words the degree of indoor air pollution at gymnasiums and exercising rooms of the folk wrestling is very high, fundamental solution and countermeasure plan should be presented.

  • PDF

A performance analysis of layered LDPC decoder for mobile WiMAX system (모바일 WiMAX용 layered LDPC 복호기의 성능분석)

  • Kim, Eun-Suk;Kim, Hae-Ju;Shin, Kyung-Wook
    • Journal of the Korea Institute of Information and Communication Engineering
    • /
    • v.15 no.4
    • /
    • pp.921-929
    • /
    • 2011
  • This paper describes an analysis of the decoding performance and decoding convergence speed of layered LDPC(low-density parity-check) decoder for mobile WiMAX system, and the optimal design conditions for hardware implementation are searched. A fixed-point model of LDPC decoder, which is based on the min-sum algorithm and layered decoding scheme, is implemented and simulated using Matlab model. Through fixed-point simulations for the block lengths of 576, 1440, 2304 bits and the code rates of 1/2, 2/3A, 2/3B, 3/4A, 3/4B, 5/6 specified in the IEEE 802.16e standard, the effect of internal bit-width, block length and code rate on the decoding performance are analyzed. Simulation results show that fixed-point bit-width larger than 8 bits with integer part of 5 bits should be used for acceptable decoding performance.

Fast Multi-Rate LDPC Encoder Architecture for WiBro System (WiBro 시스템을 위한 고속 LDPC 인코더 설계)

  • Kim, Jeong-Ki;S.P., Balakannan;Lee, Moon-Ho
    • Journal of the Institute of Electronics Engineers of Korea TC
    • /
    • v.45 no.7
    • /
    • pp.1-8
    • /
    • 2008
  • Low Density Parity Check codes(LDPC) are recently focused on communication systems due to its good performance. The standard of WiBro has also included LDPC codes as a channel coding. The weak point of implementation for LDPC encoder is that conventional binary Matrix Vector Multiplier has many clock cycles which limit throughput. In this paper, we propose semi-parallel architecture by using cyclic shift registers and exclusive-OR without conventional Matrix Vector Multipliers over the standard parity check matrices with Circulant Permutation Matrices(CPM). Furthermore, multi-rate encoder is designed by using proposed architecture. Our encoder with multi-rate for IEEE 802.16e LDPC has lower clock cycles and higher throughput.

Study on the Development of Meridian Impedance Measurement System (경락 임피던스 측정 시스템 개발에 관한 연구)

  • Lee, Woo-Cheol;Yin, Chang-Shik;Min, Kyoung-Kee
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.58 no.2
    • /
    • pp.422-429
    • /
    • 2009
  • Meridian which used as the basic theory of acupuncture treatment, is an important functional connection system of acupuncture point in oriental medicine. Yangdorak and EAV have lack of precision because of using 2-electrode method, occurring high non-uniformed current density and electrode contact status on electrode placement spot. Therefore we implemented a meridian impedance measurement system for measuring meridian impedance using 4-electrode method. In order to confirm the precision of developed system, we made an constant current characteristic experiment using standard resistor. As a results of clinical study with 18 subjects, the meridian impedance showed that reproductivity and repeatability of HT7 acupuncture point are $0.515[k{\Omega}]{\pm}0.000$(mean${\pm}$standard deviation) and $0.515[k{\Omega}]{\pm}0.002$, respectively. And reproductivity and repeatability of PC7 are $0.521[k{\Omega}]{\pm}0.000$ and $0.521[{\Omega}]{\pm}0.001$ respectively. The proposed system was stable and reliable. Therefore this study proved AC impedance method to valid in measuring meridian impedance, and also verified precision and repeatability of the proposed meridian impedance measurement system. The proposed system will serve as more effective method of measuring meridian phenomena as a bioelectric signal in clinical practice.

A performance analysis of LDPC decoder for IEEE 802.16e WiMAX System (IEEE 802.16e WiMAX용 LDPC 복호기의 성능분석)

  • Kim, Eun-Suk;Kim, Hae-Ju;Shin, Kyung-Wook
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
    • /
    • 2010.10a
    • /
    • pp.722-725
    • /
    • 2010
  • In this paper, BER performance and error convergence speed of layered LDPC(Low Density Parity Check) decoder which supports IEEE 802.16e WiMAX standard is analyzed, and optimal design conditions for hardware implementation are derived. A LDPC decoder is modeled and simulated at AWGN channel with QPSK modulation by Matlab. The parity check matrix(PCM) for IEEE 802.16e standard which has block lengths of 576, 1440, 2304 and code rates of 1/2, 2/3A, 2/3B, 3/4A, 3/4B, 5/6 are used. Fixed-point simulation results show that fixed-point bit-width should be more than 8 bits for acceptable decoding performance.

  • PDF

Pointwise Estimation of Density of Heteroscedastistic Response in Regression

  • Hyun, Ji-Hoon;Kim, Si-Won;Lee, Sung-Dong;Byun, Wook-Jae;Son, Mi-Kyoung;Kim, Choong-Rak
    • The Korean Journal of Applied Statistics
    • /
    • v.25 no.1
    • /
    • pp.197-203
    • /
    • 2012
  • In fitting a regression model, we often encounter data sets which do not follow Gaussian distribution and/or do not have equal variance. In this case estimation of the conditional density of a response variable at a given design point is hardly solved by a standard least squares method. To solve this problem, we propose a simple method to estimate the distribution of the fitted vales under heteroscedasticity using the idea of quantile regression and the histogram techniques. Application of this method to a real data sets is given.

Bayesian estimation for finite population proportions in multinomial data

  • Kwak, Sang-Gyu;Kim, Dal-Ho
    • Journal of the Korean Data and Information Science Society
    • /
    • v.23 no.3
    • /
    • pp.587-593
    • /
    • 2012
  • We study Bayesian estimates for finite population proportions in multinomial problems. To do this, we consider a three-stage hierarchical Bayesian model. For prior, we use Dirichlet density to model each cell probability in each cluster. Our method does not require complicated computation such as Metropolis-Hastings algorithm to draw samples from each density of parameters. We draw samples using Gibbs sampler with grid method. We apply this algorithm to a couple of simulation data under three scenarios and we estimate the finite population proportions using two kinds of approaches We compare results with the point estimates of finite population proportions and their standard deviations. Finally, we check the consistency of computation using differen samples drawn from distinct iterates.

A Study on the Diffusion Behavior of Leak Gas from Underground Gas Pipeline (지하매설 가스배관의 가스 누출시 지하 확산거동에 관한 연구)

  • Choi S.C.;Jo Y.D.;Kim K.S.
    • Journal of the Korean Institute of Gas
    • /
    • v.3 no.2 s.7
    • /
    • pp.43-52
    • /
    • 1999
  • An experimental chamber was fabricated to observe the gas diffusion behavior of leak gas from underground city-gas pipeline. It was made of acryl so that feeding of gas and the measuring points of the gas could be varied in each experiment. The MOS sensors were used to measure the concentrations of leak gas. The soil media such as the Jumunjin standard sand and the granite weathered soil were used to measure the gas diffusion and the change of leak gas concentrations was measured with time for various gas flow rate. As the distance between the leak point of gas and the measuring point of MOS sensor decreases, or the leak rate increases, the detection time of gas at a measuring points decreases and the gas concentration increases quickly and the concentration of the gas at steady state also increases. As the density of granite weathered soil is higher than that of Jumunjin standard sand for compaction, the detection time of leak gas in the granite weathered soil was longer than that in the Jumunjin standard soil. The leak gas concentrations in the granite weathered soil were lower than those in the Jumunjin standard sand at the beginning of gas leaking from a pipe, but inverse phenomenon was occured at steady state.

  • PDF