Simulation

2458's picture

Shrinkage Estimators for Reliability Function

Journal Title, Volume, Page: 
An-Najah Univ. J.Res.(N.Se)Vol .27, p141-151
Year of Publication: 
2013
Authors: 
Mohammad Qabaha
Department of Mathematics, Faculty of Science, An-Najah National University, Palestine
Current Affiliation: 
Department of Statistics, Faculty of Science, An-Najah National University , Nablus, Palestine
Preferred Abstract (Original): 

A variety of shrinkage methods for estimating unknown parameters has been considered. We derive and compare the shrinkage estimators for the reliability function of the two-parameter exponential distribution. Simulation experiments are used to study the performances of these estimators.

2458's picture

Ordinary and Bayesian Shrinkage Estimation

Journal Title, Volume, Page: 
An-Najah Univ. J.Res.(N.Se)Vol .21, 101-116
Year of Publication: 
2007
Authors: 
Mohammad Qabaha
Department of Mathematics, Faculty of Science, An-Najah National University, Palestine
Current Affiliation: 
Department of Statistics, Faculty of Science, An-Najah National University, Nablus, Palestine
Preferred Abstract (Original): 

In this paper a variety of shrinkage methods for estimating unknown population parameters has been considered. Aprior distribution for the parameters around their natural origins has been postulated and the ordinary Bayes estimators are used in place of natural origins in the ordinary shrinkage estimators to obtain Bayesian shrinkage estimators. The results are applied to the problem of estimating the location and scale parameters and the reliability function of the two-parameter exponential distribution. Simulation experiments are used to study the performances of these estimators.

Wael alhajyaseen's picture

Stochastic Approach for Modeling the Effects of Intersection Geometry on Turning Vehicle Paths

Journal Title, Volume, Page: 
Transportation Research Part C: Emerging Technologies Volume 32, July 2013, Pages 179–192
Year of Publication: 
2013
Authors: 
Wael Alhajyaseen
Department of Civil Engineering, An-Najah National University, Nablus P.O. Box 7, Palestine
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Nablus P.O. Box 7, Palestine
Miho Asano
Department of Civil Engineering, Nagoya University, Nagoya 464-8603, Japan
Hideki Nakamura
Department of Civil Engineering, Nagoya University, Nagoya 464-8603, Japan
Dang Minh Tan
Department of Civil Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan
Preferred Abstract (Original): 
Analytical evaluation techniques for the safety performance of signalized intersections are applicable to limited scenarios and conditions, whereas simulation-based analysis tools are very flexible and promising. This study is part of intensive efforts to develop a microscopic simulation model for the safety assessment of signalized intersections. One important aspect of analyzing driver maneuver is vehicle paths. Broadly varying paths may result in widely distributed potential conflict points with other movements, which may affect the occurrence probability of severe conflicts. Therefore, this study aims to develop a technique to reproduce the variations in the paths of turning vehicles, considering intersection geometry, vehicle type, and speed. Several signalized intersections in Nagoya City, Japan, with various traffic and geometric characteristics were videotaped. The analysis revealed that the paths of right-turning vehicles (left-hand traffic) are more sensitive to the vehicle speed and turning angle whereas those of left-turning vehicles are more sensitive to the intersection corner radius, turning angle, and vehicle speed. For modeling individual vehicle paths, this study applies the Euler-spiral-based approximation methodology where each trajectory is fitted by an entering Euler spiral curve followed by a circular curve and an exit Euler spiral curve. The proposed models are unique since they provide a realistic and rational representation of the variations in turning vehicles’ paths inside intersections.
Wael alhajyaseen's picture

Estimation of Left-turning Vehicle Maneuvers for the Assessment of Pedestrian Safety at Intersections

Journal Title, Volume, Page: 
Journal of International Association of Traffic and Safety Sciences, IATSS Research, , Elsevier, Vol.36, Issue 1, pp. 66-74
Year of Publication: 
2012
Authors: 
Wael Alhajyaseen
Department of Civil Engineering, Faculty of Engineering, An-Najah National University, Nablus, P.O. Box 7, Palestine
Current Affiliation: 
Department of Civil Engineering, An-Najah National University, Nablus P.O. Box 7, Palestine
Miho Asano
Department of Civil Engineering, Nagoya University, Nagoya 464-8603, Japan
Hideki Nakamura
Department of Civil Engineering, Nagoya University, Nagoya 464-8603, Japan
Preferred Abstract (Original): 
Improving pedestrian safety at intersections remains a critical issue. Although several types of safety countermeasures, such as reforming intersection layouts, have been implemented, methods have not yet been established to quantitatively evaluate the effects of these countermeasures before installation. One of the main issues in pedestrian safety is conflicts with turning vehicles. This study aims to develop an integrated model to represent the variations in the maneuvers of left-turners (left-hand traffic) at signalized intersections that dynamically considers the vehicle reaction to intersection geometry and crossing pedestrians. The proposed method consists of four empirically developed stochastic sub-models, including a path model, free-flow speed profile model, lag/gap acceptance model, and stopping/clearing speed profile model. Since safety assessment is the main objective driving the development of the proposed model, this study uses post-encroachment time (PET) and vehicle speed at the crosswalk as validation parameters. Preliminary validation results obtained by Monte Carlo simulation show that the proposed integrated model can realistically represent the variations in vehicle maneuvers as well as the distribution of PET and vehicle speeds at the crosswalk.
Aladdin Masri's picture

Performance Analysis Of IEEE 802.11b Wireless Networks With Object Oriented Petri Nets

Journal Title, Volume, Page: 
Electronic Notes in Theoretical Computer Science
Year of Publication: 
2009
Authors: 
Aladdin Masri
LAGIS - CNRS UMR 8146, Ecole Centrale de Lille - Cit Scientifique BP 48, 59651 Villeneuve d'ASCQ, France
Current Affiliation: 
Department Of Computer Engineering, An-Najah National University, Palestine
Thomas Bourdeaud'huy
LAGIS - CNRS UMR 8146 Ecole Centrale de Lille - Cit Scienti que BP 48 59651 Villeneuve d'ASCQ, France
Armand Toguyeni
LAGIS - CNRS UMR 8146 Ecole Centrale de Lille - Cit Scienti que BP 48 59651 Villeneuve d'ASCQ, France
Preferred Abstract (Original): 

Communication protocols are often investigated using simulation. This paper presents a performance study of the distributed coordination function of 802.11 networks. Firstly, our study illustrates the different classes of Petri Nets used for modeling network protocols and their robustness in modeling based on formal methods. Next we propose a detailed 802.11b model based on Object-oriented Petri Nets that precises backoff  procedure and time synchronization. Then, performance analyses are evaluated by simulation for a dense wireless network and compared with other measurements approaches. Our main goal is to propose a modular model that will enable to evaluate the impact of network performances on the performances of distributed discrete event systems.

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