• Title/Summary/Keyword: 확률 모델

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Performance Analysis of Spectrum Sensing using CSI with False Alarm Selection (채널상태정보에 따른 False alarm 선택 스펙트럼 센싱 성능 분석)

  • Lee, Mi Sun;Kim, Jin Young
    • Journal of Satellite, Information and Communications
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    • v.8 no.4
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    • pp.1-5
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    • 2013
  • CR(Cognitive Radio) technology is maximized frequency reuse using unused frequency band. Conventional cooperative spectrum sensing has fixed false alarms. so all cooperative user has equal threshold. This problem is caused degradation of detection probability. so we propose and analysis the system model that false alarm differential setting through CSI(channel state information) for resonable threshold. Simulation results show improvement of detection probability.

Performance Analysis of Energy Detection Spectrum Sensing Using Adaptive Threshold through Controlling False alarms (오경보 확률 제어를 통한 적응적 임계치 사용 에너지 검출 스펙트럼 센싱의 성능 분석)

  • Seo, SungIl;Lee, MiSun;Kim, Jinyoung
    • Journal of Satellite, Information and Communications
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    • v.8 no.1
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    • pp.61-65
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    • 2013
  • In this paper, we propose system model to solve conventional threshold problem of using fixed false alarm for energy spectrum sensing. Spectrum sensing reliability is ensured when Secondary user have high SNR. Thus, it is not reasonable using fixed optional false alarm without considering CR user's SNR. So, we propose adaptive threshold method. adaptive threshold is decided by controling FA according to CR user's SNR.

확률적(確率的) 환경부하(環境負荷) 조건(條件)에서의 공해배출기준(公害排出基準) 최적성(最適性)에 관한 실증연구(實證硏究)

  • Cha, Geun-Ho;Gang, Man-Ok
    • Environmental and Resource Economics Review
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    • v.4 no.1
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    • pp.17-40
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    • 1994
  • 스웨덴의 펄프 제지산업을 대상으로 관찰해 보면 대부분의 기업은 허가된 수준보다는 덜 오염시키고 있다. 이를 설명하기 위하여 우리는 환경 부하(waste load)가 확률적이라는 가정에 의존하는 접근법을 제안하였다. 동 모델에 따르면 기업은 너무 높은 기대벌금을 회피하기 위하여 평균적으로 허용된 수준보다는 덜 오염시키는 것이 이윤을 가짐을 알 수 있다. 그 이유는 허가된 수준과 기대된 환경 부하의 차이가 제한규정을 위반하지 않는 확률을 증가시키기 때문이다. 우리의 이론으로부터 나타나는 또 다른 결과는 규제의 변화가 기업의 이윤과 환경에 주는 영향은 대부분의 경우에 적발되는 확률, 지불하는 벌금 수준 그리고 불확실성을 가능한한 줄이기 위해 드는 비용에 대한 기업의 인식에 달려 있다는 것이다. 오염배출의 확률분포에서 분산을 감소시키는데 드는 비용이 계획된 배출량을 감소시키는 데 드는 비용에 비해서 적다면, 기업은 오염 배출을 증가시키는 것이 이득이 됨을 발견할 것이며, 분산을 감소시킴으로서 규제준수 확률을 증가시킬 것이다. 우리는 동 산업에서 허가시스템이 기업들에게 영향을 미쳐왔다는 것을 실증분석을 통해 발견하였다. 더구나, 비표백 펄프와 쇄목 펄프를 생산하는 기업은 표백 펄프를 생산하는 기업보다 허가된 배출수준의 변화에 더 민감한 것처럼 보임을 발견하였다.

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Probabilistic Part-Of-Speech Determination for Efficient English-Korean Machine Translation (효율적 영한기계번역을 위한 확률적 품사결정)

  • Kim, Sung-Dong;Kim, Il-Min
    • The KIPS Transactions:PartB
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    • v.17B no.6
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    • pp.459-466
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    • 2010
  • Natural language processing has several ambiguity problems, and English-Korean machine translation especially includes those problems to be solved in each translation step. This paper focuses on resolving part-of-speech ambiguity of English words in order to improve the efficiency of English analysis, which is in part of efforts for developing practical English-Korean machine translation system. In order to improve the efficiency of the English analysis, the part-of-speech determination must be fast and accurate for being integrated with machine translation system. This paper proposes the probabilistic models for part-of-speech determination. We use Penn Treebank corpus in building the probabilistic models. In experiment, we present the performance of the part-of-speech determination models and the efficiency improvement of the machine translation system by the proposed part-of-speech determination method.

Probabilistic Analysis of Repairing Cost Considering Random Variables of Durability Design Parameters for Chloride Attack (염해-내구성 설계 변수에 변동성에 따른 확률론적 보수비용 산정 분석)

  • Lee, Han-Seung;Kwon, Seung-Jun
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.22 no.1
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    • pp.32-39
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    • 2018
  • Repairing timing and the extended service life with repairing are very important for cost estimation during operation. Conventionally used model for repair cost shows a step-shaped cost elevation without consideration of variability of extended service life due to repairing. In the work, RC(Reinforced Concrete) Column is considered for probabilistic evaluation of repairing number and cost. Two mix proportions are prepared and chloride behavior is evaluated with quantitative exterior conditions. The repairing frequency and cost are investigated with varying service life and the extended service life with repairing which were derived from the chloride behavior analysis. The effect of COV(Coefficient of Variation) on repairing frequency is small but the 1st repairing timing is shown to be major parameter. The probabilistic model for repairing cost is capable of reducing the number of repairing with changing the intended service life unlike deterministic model of repairing cost since it can provide continuous repair cost with time.

Investigation of Detectable Crack Length in a Bolt Hole Using Eddy Current Inspection (와전류탐상검사를 이용하여 탐지 가능한 볼트홀 내부 균열 길이 연구)

  • Lee, Dooyoul;Yang, Seongun;Park, Jongun;Baek, Seil;Kim, Soonkil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.8
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    • pp.729-736
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    • 2017
  • In this study, the physics-based model and machine learning technique were used to conduct model-assisted probability of detection (MAPOD) experiments. The possibility of using in-service cracked parts was also investigated. Bolt hole shaped specimens with fatigue crack on the hole surface were inspected using eddy current inspection. Owing to MAPOD, the number of experimental factors decreased significantly. The uncertainty in the crack length measurement for in-service cracked parts was considered by the application of Monte Carlo simulation.

Assessment of spalling occurrence using fuzzy probability theory and damage index in underground openings (퍼지확률이론과 손상지수를 이용한 지하암반공동에서의 스폴링 발생 평가)

  • Bang, Joon-Ho;Lee, Kang-Hyun;Lee, In-Mo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.12 no.1
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    • pp.15-29
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    • 2010
  • Spalling is a kind of instability phenomenon of surrounding rock around underground openings subjected to high in-situ stress according to the development of extension fractures. Three kinds of spalling criteria have been presented so far; however, all spalling criteria have the range of values so that the fuzziness and vagueness of spalling criterion cannot be avoided. In this study, a new fuzzy probability model is proposed to predict the probability of spalling in a systematic way by using fuzzy probability theory. Many of the underground opening projects worldwide are evaluated with the proposed method. Prediction results expressed as the spalling probability agree well with the in-situ observations. In particular, a new fuzzy probability model considering all three evaluation indices of spalling by adopting weighting factors based on relative reliability among three evaluation indices is able to resolve erroneous prediction of spalling by choosing only one prediction method. Moreover, the more reasonable value of spalling probability could have been obtained by adopting the modified damage index to the newly proposed fuzzy probability model.

Probabilistic Evaluation on Prediction Accuracy of the Strains by Double Surface and Single Surface Constitutive Model (확률론에 의환 Double Surface와 Single Surface 구성모델의 변형을 예측 정도의 평가)

  • Jeong, Jin Seob;Song, Young Sun;Kim, Chan Kee
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.14 no.1
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    • pp.217-229
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    • 1994
  • A probabilistic method was employed to compare the prediction accuracy of axial and volumetric strains of Lade's double surface model with that of single surface model. Several experiments were conducted to examine the variabilities of soil parameters for two models using Back-ma river sand. Mean values and standard deviations of soil parameters obtained from experimental data were used for the evaluation of the uncertainty of analyzed strains by the first order approximation. It is shown that the variabilities of parameters in the single surface model are more consistent than those of the double surface model. However, in the accuracy of axial strain by probabilistic analysis, double surface model is more stable than single surface model. It is also shown that two models are excellent in view of the accuracy of the volumetric strain. The method given in this paper may be effectively utilized to estimate the constitutive model because other results of the comparison of two models coincide with those of this paper.

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Range Detection of Wa/Kwa Parallel Noun Phrase using a Probabilistic Model and Modification Information (확률모형과 수식정보를 이용한 와/과 병렬사구 범위결정)

  • Choi, Yong-Seok;Shin, Ji-Ae;Choi, Key-Sun
    • Journal of KIISE:Software and Applications
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    • v.35 no.2
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    • pp.128-136
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    • 2008
  • Recognition of parallel structure at early stage of sentence parsing can reduce the complexity of parsing. In this paper, we propose an unsupervised language-independent probabilistic model for recongition of parallel noun structures. The proposed model is based on the idea of swapping constituents, which replies the properties of symmetry (two or more identical constituents are repeated) and of reversibility (the order of constituents is inter-changeable) in parallel structures. The non-symmetric patterns that cannot be captured by the general symmetry rule are resolved additionally by the modifier information. In particular this paper shows how the proposed model is applied to recognize Korean parallel noun phrases connected by "wa/kwa" particle. Our model is compared with other models including supervised models and performs better on recongition of parallel noun phrases.

Simulation of Groundwater Flow in Fractured Porous Media using a Discrete Fracture Model (불연속 파쇄모델을 이용한 파쇄 매질에서의 지하수 유동 시뮬레이션)

  • Park, Yu-Chul;Lee, Kang-Kun
    • Economic and Environmental Geology
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    • v.28 no.5
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    • pp.503-512
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    • 1995
  • Groundwater flow in fracture networks is simulated using a discrete fracture (DF) model which assume that groundwater flows only through the fracture network. This assumption is available if the permeability of rock matrix is very low. It is almost impossible to describe fracture networks perfectly, so a stochastic approach is used. The stochastic approach assumes that the characteristic parameters in fracture network have special distribution patterns. The stochastic model generates fracture networks with some characteristic parameters. The finite element method is used to compute fracture flows. One-dimensional line element is the element type of the finite elements. The simulation results are shown by dominant flow paths in the fracture network. The dominant flow path can be found from the simulated groundwater flow field. The model developed in this study provides the tool to estimate the influences of characteristic parameters on groundwater flow in fracture networks. The influences of some characteristic parameters on the frcture flow are estimated by the Monte Carlo simulation based on 30 realizations.

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