30 citations · 156 across the 22 of their papers we have counts for
22 papers
Inferring origin-destination distribution of agent transfer in a complex network using deep gated recurrent units
Vee-Liem Saw, Luca Vismara, Suryadi +3
Predicting the origin-destination (OD) probability distribution of agent transfer is an important problem for managing complex systems. However, prediction accuracy of associated s…
Can bus bunching reduce waiting time?
Luca Vismara, Vee-Liem Saw, Lock Yue Chew
Bus bunching is ostensibly regarded as a detrimental phenomenon in bus systems. We study a bus loop with two bus stops, one regular and one spike bus stop, where bunched buses can…
Bunching Dynamics of Buses in a Loop
Luca Vismara, Vee-Liem Saw, Lock Yue Chew
Bus bunching is a curse of transportation systems such as buses in a loop. Here we present an analytical method to find the number of revolutions before two buses bunch in an ideal…
Optimal assignment of buses to bus stops in a loop by reinforcement learning
Luca Vismara, Lock Yue Chew, Vee-Liem Saw
Bus systems involve complex bus-bus and bus-passengers interactions. We study the problem of assigning buses to bus stops to minimise the average waiting time of passengers, W. An…
Chaotic semi-express buses in a loop
Vee-Liem Saw, Luca Vismara, Lock Yue Chew
Urban mobility involves many interacting components: buses, cars, commuters, pedestrians, trains etc., making it a very complex system to study. Even a bus system responsible for d…
Analysis and simulation of intervention strategies against bus bunching by means of an empirical agent-based model
Wei Liang Quek, Ning Ning Chung, Vee-Liem Saw +1
In this paper, we propose an Empirically-based Monte Carlo Bus-network (EMB) model as a test bed to simulate intervention strategies to overcome the inefficiencies of bus bunching.…
Stability of anti-bunched buses and local unidirectional Kuramoto oscillators
Lock Yue Chew, Vee-Liem Saw, Yi En Ian Pang
Inspired by our recent work that relates bus bunching as a phenomenon of synchronisation of phase oscillators, we construct a model of Kuramoto oscillators that follows an analogou…
Intelligent buses in a loop service: Emergence of no-boarding and holding strategies
Vee-Liem Saw, Luca Vismara, Lock Yue Chew
We study how intelligent buses serving a loop of bus stops learn a \emph{no-boarding strategy} and a \emph{holding strategy} by reinforcement learning. The high level no-bo…
No-boarding buses: Agents allowed to cooperate or defect
Vee-Liem Saw, Lock Yue Chew
We study a bus system with a no-boarding policy, where a "slow" bus may disallow passengers from boarding if it meets some criteria. When the no-boarding policy is activated, peopl…
No-boarding buses: Synchronisation for efficiency
Vee-Liem Saw, Lock Yue Chew
We investigate a no-boarding policy in a system of buses serving bus stops in a loop, which is an entrainment mechanism to keep buses synchronised in a reasonably staggered…
Bus bunching as a synchronisation phenomenon
Vee-Liem Saw, Ning Ning Chung, Wei Liang Quek +2
Bus bunching is a perennial phenomenon that not only diminishes the efficiency of a bus system, but also prevents transit authorities from keeping buses on schedule. We present a p…
Bondi mass with a cosmological constant
Vee-Liem Saw
The mass loss of an isolated gravitating system due to energy carried away by gravitational waves with a cosmological constant was recently worked out, using the Newman-Pe…
Asymptotically simple spacetimes and mass loss due to gravitational waves
Vee-Liem Saw
The cosmological constant used to be a freedom in Einstein's theory of general relativity, where one had a proclivity to set it to zero purely for convenience. The signs of …
Peeling property and asymptotic symmetries with a cosmological constant
Vee-Liem Saw, Freeman Chee Siong Thun
This paper establishes two things in an asymptotically (anti-)de Sitter spacetime, by direct computations in the physical spacetime (i.e. with no involvement of spacetime compactif…
Mass loss due to gravitational waves with
Vee-Liem Saw
The theoretical basis for the energy carried away by gravitational waves that an isolated gravitating system emits was first formulated by Hermann Bondi during the 1960s. Recent fi…
Behaviour of asymptotically electro- spacetimes
Vee-Liem Saw
We present the asymptotic solutions for spacetimes with non-zero cosmological constant coupled to Maxwell fields, using the Newman-Penrose formalism. This extends a recent work…
Mass-loss of an isolated gravitating system due to energy carried away by gravitational waves with a cosmological constant
Vee-Liem Saw
We derive the asymptotic solutions for vacuum spacetimes with non-zero cosmological constant , using the Newman-Penrose formalism. Our approach is based exclusively on the physi…
Constructing vacuum spacetimes by generating manifolds of revolution around a curve
Vee-Liem Saw
We develop a general perturbative analysis on vacuum spacetimes which can be constructed by generating manifolds of revolution around a curve, and apply it to the Schwarzschild met…
A theory of static friction between homogeneous surfaces based on compressible elastic smooth microscopic inclines
Freeman Chee Siong Thun, Vee-Liem Saw, Kin Sung Chan
We develop a theory of static friction by modeling the homogeneous surfaces of contact as being composed of a regular array of compressible elastic smooth microscopic inclines. Sta…
A rotating universe outside a Schwarzschild black hole where spacetime itself non-uniformly rotates
Vee-Liem Saw
We study a non-uniformly rotating universe outside a Schwarzschild black hole by generating a time-dependent manifold of revolution around a straight line. In this simple model whe…
Helicalised fractals
Vee-Liem Saw, Lock Yue Chew
We formulate the helicaliser, which replaces a given smooth curve by another curve that winds around it. In our analysis, we relate this formulation to the geometrical properties o…
Curved traversable wormholes in (3+1)-dimensional spacetime
Vee-Liem Saw, Lock Yue Chew
We present the general method of constructing curved traversable wormholes in (3+1)-d spacetime and proceed to thoroughly discuss the physics of a zero tidal force metric without c…