Simulating Congestion Dynamics of Train Rapid Transit using Smart Card Data

Investigating congestion in train rapid transit systems (RTS) in today's urban cities is a challenge compounded by limited data availability and difficulties in model validation. Here, we integrate information from travel smart card data, a mathematical model of route choice, and a full-scale agent-based model of the Singapore RTS to provide a more comprehensive understanding of the congestion dynamics than can be obtained through analytical modelling alone. Our model is empirically validated, and allows for close inspection of the dynamics including station crowdedness, average travel duration, and frequency of missed trains---all highly pertinent factors in service quality. Using current data, the crowdedness in all 121 stations appears to be distributed log-normally. In our preliminary scenarios, we investigate the effect of population growth on service quality. We find that the current population (2 million) lies below a critical point; and increasing it beyond a factor of $\sim10\%$ leads to an exponential deterioration in service quality. We also predict that incentivizing commuters to avoid the most congested hours can bring modest improvements to the service quality provided the population remains under the critical point. Finally, our model can be used to generate simulated data for analytical modelling when such data are not empirically available, as is often the case.Comment: 10 pages, 5 figures, submitted to International Conference on Computational Science 201

Model-based Decentralized Embedded Diagnosis inside Vehicles: Application to Smart Distance Keeping Function

International audienceAbstract—In this paper, the deployment of a fault diagnosis strategy in the Smart Distance Keeping (SDK) system with a decentralized architecture is presented. The SDK system is an advanced version of the Adaptive Cruise Control (ACC) system, implemented in a Renault-Volvo Trucks vehicle. The main goal of this work is to analyze measurements, issued from the SDK elements, in order to detect, to localize and to identify some faults that may be produced. Our main contribution is the proposition of a decentralized approach permitting to carry out an on-line diagnosis without computing the global model and to deploy it on several control units. This paper explains the model-based decentralized solution and its application to the embedded diagnosis of the SDK system inside truck with five control units connected via a CAN-bus using ”Hardware In the Loop” (HIL) technique. We also discuss the constraints that must be fulfilled

Smart distance keeping: modeling and perspectives for embedded diagnosis

International audienceThis paper presents a detailed description of an advanced Adaptive Cruise Control (ACC) system implemented on a Renault-Volvo Trucks vehicle. One of the main differences between this new system, which is called the Smart Distance Keeping (SDK), and the classical ACC is the choice of the safe distance. This later is the distance between the vehicle (with the ACC or the SDK system) and the front obstacle (which may be a vehicle). It is supposed fix in the case of the ACC, while variable in the case of the SDK. The variation of this distance (in the case of SDK) depends essentially on the relative velocity between the vehicle and the front obstacle. The choice of this distance influences the velocity regulation. The main contribution of this work is on the SDK system architecture, the design of its environment model, and the proposition of a detection and isolation strategy for some of the possible faults that may be produced on the system

Persepsi kepuasan pelanggan terhadap produk sistem perbankan Islam (SPI) bank Islam dan konvensional

Sisrem perbankan Islam (SPI) merupakan salah satu bidang dalam pengurusan muamalat Islam. Perkembangan di Malaysia berdasar kepada kesedaran permintaan masyarakat terhadap suaru sistem yang bebas daripada unsur gharar dan riba. Selain itu, kerajaan juga memberi galakan dan menerapkan nilai Islam dalam sektor awam dan juga swasta. Kini,terdapat tiga buah institusi perbankan Islam di Malaysia iaitu Bank Islam Malaysia Berhad (BIMB), Bank Muamalat Malaysia Berhad (BMMB) dan Bank Kerjasama Rakyat Malaysia (Syed Mohd.Ghazali Wafa, Muhamad Nasri, & Mohd Hizam, 2003).Jumlah bank Islam tersebut bertambah pada tahun 2005 dengan RHB bank Islam, Bank Tijari dan akan terus bertambah mengikut kelulusan bank negara. Sementara itu, semua bank konvensional juga menawarkan produk SPI sekali gus mewujudkan persaingan dengan bank Islam

Ratib al-Attas menurut perspektif al-Quran dan hadis

This article aims to evaluate the source of 17 dhikr in Ratib al-Άttas based on Quran, Hadith and scholar views on the meaning and purpose of dhikr. Applications Ratib al-Attas ceremony was conducted over 90 years ago in the state of Johor. In addition, the application Ratib al-Άttas assessment and justification is given from the perspective of Islamic practices. The method used is by clarifying the position of remembrance 17 Ratib al-Άttas more reliable by practitioners; avoid confusion and misunderstanding of the doctrine of Ratib al-Attas. The results showed that all 17 dhikr Ratib al-Άttas and the practice carried out are consistent with the arguments of al-Quran and Hadith. Based on this finding several suggestions is made to encourage the expend development of dhikr al-Άttas Ratib practice among the Muslim community in Malaysia

Vérification de la sûreté des systèmes hybrides (calcul d atteignabilité par abstractions linéaires)

Dans cette thèse, nous proposons des techniques algorithmiques de vérification formelle de propriétés pour des systèmes dynamiques hybrides (continus/discrets). Ces techniques de vérification se basent sur le calcul de l espace atteignable à partir d une région initiale pour déterminer si l intersection de cet espace avec le domaine à éviter est bien vide. Notre méthode consiste à partitionner l espace d état du système complexe en régions et à approximer pour chacune de ces régions la dynamique du système étudié par une dynamique plus simple. Nous présentons des extensions à une proposition précédente afin de prendre en compte des incertitudes dans les dynamiques affines. Dans un premier temps cette incertitude est considérée comme invariante. Dans un second temps nous la considérons variante. Cette deuxième extension permet de considérer l atteignabilité des systèmes non-linéaires.This thesis offers a practical framework for the formal verification properties of hybrid dynamic systems. In other words, the reachable space from an initial set of states is computed, and this space is then checked for intersection with the set to be of undesirable states. Our method computes an over approximation of the reachable space. This method is based on a partition of the continuous state space and on an abstraction of the continuous dynamics in each cell by a simpler one. We present an extension to uncertain systems of an approach which computes the reachable space of autonomous hybrid affine systems. Two cases are distinguished in order to analyze the reachability of these systems. One concerns fixed uncertainties in time and the other time dependant uncertainties variables. An extension of the approach offered for the uncertain hybrid affine systems is then developed to take into account non-linear dynamics.RENNES1-BU Sciences Philo (352382102) / SudocSudocFranceF

Smart distance keeping: modeling and perspectives for embedded diagnosis

International audienceThis paper presents a detailed description of an advanced Adaptive Cruise Control (ACC) system implemented on a Renault-Volvo Trucks vehicle. One of the main differences between this new system, which is called the Smart Distance Keeping (SDK), and the classical ACC is the choice of the safe distance. This later is the distance between the vehicle (with the ACC or the SDK system) and the front obstacle (which may be a vehicle). It is supposed fix in the case of the ACC, while variable in the case of the SDK. The variation of this distance (in the case of SDK) depends essentially on the relative velocity between the vehicle and the front obstacle. The choice of this distance influences the velocity regulation. The main contribution of this work is on the SDK system architecture, the design of its environment model, and the proposition of a detection and isolation strategy for some of the possible faults that may be produced on the system