7,096 research outputs found
Train schedule coordination at an interchange station through agent negotiation
In open railway markets, coordinating train schedules at an interchange station requires negotiation between two independent train operating companies to resolve their operational conflicts. This paper models the stakeholders as software agents and proposes an agent negotiation model to study their interaction. Three negotiation strategies have been devised to represent the possible objectives of the stakeholders, and they determine the behavior in proposing offers to the proponent. Empirical simulation results confirm that the use of the proposed negotiation strategies lead to outcomes that are consistent with the objectives of the stakeholders
Detecting entanglement with non-hermitian operators
We derive several entanglement conditions employing non-hermitian operators.
We start with two conditions that were derived previously for field mode
operators, and use them to derive conditions that can be used to show the
existence of field-atom entanglement and entanglement between groups of atoms.
The original conditions can be strengthened by making them invariant under
certain sets of local unitary transformations, such as Gaussian operations. We
then apply these conditions to several examples, such as the Dicke model. We
conclude with a short discussion of how local uncertainty relations with
non-hermitian operators can be used to derive entanglement conditions.Comment: Typos correcte
Conditions for entanglement in multipartite systems
We introduce two entanglement conditions that take the form of inequalities
involving expectation values of operators. These conditions are sufficient
conditions for entanglement, that is if they are satisfied the state is
entangled, but if they are not, one can say nothing about the entanglement of
the state. These conditions are quite flexible, because the operators in them
are not specified, and they are particularly useful in detecting multipartite
entanglement. We explore the range of utility of these conditions by
considering a number of examples of entangled states, and seeing under what
conditions entanglement in them can be detected by the inequalities presented
here.Comment: accepted for publication in Physical Review
A new and efficient intelligent collaboration scheme for fashion design
Technology-mediated collaboration process has been extensively studied for over a decade. Most applications with collaboration concepts reported in the literature focus on enhancing efficiency and effectiveness of the decision-making processes in objective and well-structured workflows. However, relatively few previous studies have investigated the applications of collaboration schemes to problems with subjective and unstructured nature. In this paper, we explore a new intelligent collaboration scheme for fashion design which, by nature, relies heavily on human judgment and creativity. Techniques such as multicriteria decision making, fuzzy logic, and artificial neural network (ANN) models are employed. Industrial data sets are used for the analysis. Our experimental results suggest that the proposed scheme exhibits significant improvement over the traditional method in terms of the time–cost effectiveness, and a company interview with design professionals has confirmed its effectiveness and significance
Learning Task Specifications from Demonstrations
Real world applications often naturally decompose into several sub-tasks. In
many settings (e.g., robotics) demonstrations provide a natural way to specify
the sub-tasks. However, most methods for learning from demonstrations either do
not provide guarantees that the artifacts learned for the sub-tasks can be
safely recombined or limit the types of composition available. Motivated by
this deficit, we consider the problem of inferring Boolean non-Markovian
rewards (also known as logical trace properties or specifications) from
demonstrations provided by an agent operating in an uncertain, stochastic
environment. Crucially, specifications admit well-defined composition rules
that are typically easy to interpret. In this paper, we formulate the
specification inference task as a maximum a posteriori (MAP) probability
inference problem, apply the principle of maximum entropy to derive an analytic
demonstration likelihood model and give an efficient approach to search for the
most likely specification in a large candidate pool of specifications. In our
experiments, we demonstrate how learning specifications can help avoid common
problems that often arise due to ad-hoc reward composition.Comment: NIPS 201
Passenger flow and station facilities modelling for metro station layout design
This paper presents the simulation model development of passenger flow in a metro station. The model allows studies of passenger flow in stations with different layouts and facilities, thus providing valuable information, such as passenger flow and density of passenger at critical locations and passenger-handling facilities within a station, to the operators. The adoption of the concept of Petri nets in the simulation model is discussed. Examples are provided to demonstrate its application to passenger flow analysis, train scheduling and the testing of alternative station layouts
Validated CFD simulations of vortex formation in jet engine test cells
Vortices can be produced and ingested in to the intake of a jet engine during its operation. This can occur when the plane is on the runway during take-off, or during engine tests in a test cell. The vortex can throw debris into the intake or stall the compressor, causing severe damage to the engine. The runway problem is solved by keeping the runway clear of debris and scheduling the throttle appropriately. However vortices can still occur in test cells. To eliminate vortices at the design stage it is necessary to be able to predict the onset of the vortex. This paper seeks to use the commercial CFD code Fluent to investigate both the runway and test cell problem. The runway problem has been investigated in previous wind tunnel studies by other authors. These studies were recreated in a CFD simulation reported in detail elsewhere. The threshold conditions for vortex formation were located and the effects of suction tube diameter, shear in the test cell inlet, ground boundary layer thickness and suction inlet Reynolds number were investigated. With the computational techniques thus validated, the study is extended to enclosed test cell geometries. The simulations show three stages of flow regime namely regular vortex, deformed vortex and no vortex. Vortices are not formed at cell bypass ratios greater than 50-70% and stable vortices are formed at cell bypass ratios less than 20-30%. The vortex threshold is found to be lower than the threshold for suction over ground plane simulations on the Vi/Vo against H/Di graph, i.e. vortex formation occurs over a wider range of conditions when the flow is enclosed
The adaptive nature of the bone-periodontal ligament-cementum complex in a ligature-induced periodontitis rat model.
The novel aspect of this study involves illustrating significant adaptation of a functionally loaded bone-PDL-cementum complex in a ligature-induced periodontitis rat model. Following 4, 8, and 15 days of ligation, proinflammatory cytokines (TNF- α and RANKL), a mineral resorption indicator (TRAP), and a cell migration and adhesion molecule for tissue regeneration (fibronectin) within the complex were localized and correlated with changes in PDL-space (functional space). At 4 days of ligation, the functional space of the distal complex was widened compared to controls and was positively correlated with an increased expression of TNF- α. At 8 and 15 days, the number of RANKL(+) cells decreased near the mesial alveolar bone crest (ABC) but increased at the distal ABC. TRAP(+) cells on both sides of the complex significantly increased at 8 days. A gradual change in fibronectin expression from the distal PDL-secondary cementum interfaces through precementum layers was observed when compared to increased and abrupt changes at the mesial PDL-cementum and PDL-bone interfaces in ligated and control groups. Based on our results, we hypothesize that compromised strain fields can be created in a diseased periodontium, which in response to prolonged function can significantly alter the original bone and apical cementum formations
- …