447 research outputs found
Constraint Propagation in Presence of Arrays
We describe the use of array expressions as constraints, which represents a
consequent generalisation of the "element" constraint. Constraint propagation
for array constraints is studied theoretically, and for a set of domain
reduction rules the local consistency they enforce, arc-consistency, is proved.
An efficient algorithm is described that encapsulates the rule set and so
inherits the capability to enforce arc-consistency from the rules.Comment: 10 pages. Accepted at the 6th Annual Workshop of the ERCIM Working
Group on Constraints, 200
Constraint-Based Qualitative Simulation
We consider qualitative simulation involving a finite set of qualitative
relations in presence of complete knowledge about their interrelationship. We
show how it can be naturally captured by means of constraints expressed in
temporal logic and constraint satisfaction problems. The constraints relate at
each stage the 'past' of a simulation with its 'future'. The benefit of this
approach is that it readily leads to an implementation based on constraint
technology that can be used to generate simulations and to answer queries about
them.Comment: 10 pages, to appear at the conference TIME 200
Modified sorting technique to mitigate the collateral mortality of trawled school prawns (Metapenaeus macleayi)
The potential for changes to onboard handling practices in order to improve the fate of juvenile school prawns (Metapenaeus macleayi) discarded during trawling were investigated in two Australian rivers (Clarence and Hunter) by comparing a purpose-built, water-filled sorting tray against a conventional dry tray across various conditions, including the range of typical delays before the start of sorting the catch (2 min vs. 15 min). Juvenile school prawns
(n= 5760), caught during 32 and 16 deployments in each river, were caged and sacrificed at four times: immediately
(T0), and at 24 (T24), 72 (T72), and 120 (T12 0) hours after having been discarded. In both rivers, most
mortalities occurred between T0 and T24 and, after adjusting for control deaths (<12%), were greatest for the
15-min conventional treatment (up to 41% at T120). Mixed-effects logistic models revealed that in addition to the sampling time, method of sorting, and delay in sorting, the weight of the catch, salinity, and percentage cloud cover were significant predictors of mortality. Although trawling
caused some mortalities and comparable stress (measured as L -lactate) in all school prawns, use of the water tray lessened the negative impacts of some of the above factors across both the 2-min and 15-min delays in sorting so that the overall discard mortality was reduced by more than a
third. When used in conjunction with selective trawls, widespread application of the water tray should help to
improve the sustainability of trawling for school prawns
Applying Trust for Operational States of ICT-Enabled Power Grid Services
Digitalization enables the automation required to operate modern
cyber-physical energy systems (CPESs), leading to a shift from hierarchical to
organic systems. However, digitalization increases the number of factors
affecting the state of a CPES (e.g., software bugs and cyber threats). In
addition to established factors like functional correctness, others like
security become relevant but are yet to be integrated into an operational
viewpoint, i.e. a holistic perspective on the system state. Trust in organic
computing is an approach to gain a holistic view of the state of systems. It
consists of several facets (e.g., functional correctness, security, and
reliability), which can be used to assess the state of CPES. Therefore, a trust
assessment on all levels can contribute to a coherent state assessment. This
paper focuses on the trust in ICT-enabled grid services in a CPES. These are
essential for operating the CPES, and their performance relies on various data
aspects like availability, timeliness, and correctness. This paper proposes to
assess the trust in involved components and data to estimate data correctness,
which is crucial for grid services. The assessment is presented considering two
exemplary grid services, namely state estimation and coordinated voltage
control. Furthermore, the interpretation of different trust facets is also
discussed.Comment: Preprint of the article under revision for the ACM Transactions on
Autonomous and Adaptive Systems, Special Issue on 20 Years of Organic
Computin
Scanning Acoustic GHz-Microscopy in Microelectronics Failure Analysis
The ongoing trend in microelectronics aims at increasing functionality while reducing the devices footprint. This leads to the currently highly pursued approach of three-dimensional integration of individual devices with e.g. sensors and application specific integrated circuitry resulting in highly integrated and complex systems. By extending the system structure to the third spatial dimension, the aim of chip-to-wafer or wafer-to-wafer bonding techniques is no longer restricted to mechanical integration only. Techniques like adhesive bonding, Cu/Cu thermo-compression bonding or hybrid bonding have also to provide a precise formation of robust and reliable vertical electrical interconnects within the bonding interface. Furthermore, the interaction of Through-Silicon-Via technology (TSV) that enables an efficient 3D-distribution concept with the bonding technologies have to be taken into account. As a consequence, these new technological concepts lead to new defect risks which require novel and adapted inspection methods for assessing quality-related properties and understanding the physical relationship.
Today scanning acoustic microscopy (SAM) is already widely used in quality control and failure analysis applications within microelectronics development and manufacturing. The technique is particularly sensitive to material boundaries for the assessment of quality- and reliability- affecting factors like voids and inclusions, cracks, delamination, bonding defects, and many more [1]. Since 3D-integration technologies result in reduced spatial dimensions of the electrical and mechanical interconnects and, thus smaller defects, the demand on the resolution capabilities of potential inspection techniques increases. The successful application of SAM in 3D integration however, requires overcoming limitations in the achievable spatial resolution and the integration of adapted SAM analysis technologies for vertical contacts.
The current paper presents the relatively novel approach of applying acoustic microscopy in the GHz-frequency band to increase the achievable lateral resolution and the sensitivity to surface and near-surface features with resolutions in the 1 μm regime. The potential of the GHz-SAM approach will be illustrated describing the inspection of Cu-Cu interfaces in mono-metallic wire bond systems [2] and the detection and propagation-assessment of stress induced voids in thick Al-power lines for high-temperature applications. Using short focal-length transducers GHz-SAM was also applied for the detection of delaminations in sub-surface electrical lines and the detection of cracks in the passivation layer of an RFID chip and the cracks sub-surface propagation. Finally, preliminary results of on-going research addressing the inspection of Through-Silicon-Vias will be presented and discussed
Constraints in Non-Boolean Contexts
In high-level constraint modelling languages, constraints can occur in non-Boolean contexts: implicitly, in the form of partial functions, or more explicitly, in the form of constraints on local variables in non-Boolean expressions. Specifications using these facilities are often more succinct. However, these specifications are typically executed on solvers that only support questions of the form of existentially quantified conjunctions of constraints.
We show how we can translate expressions with constraints appearing in non-Boolean contexts into conjunctions of ordinary constraints. The translation is clearly structured into constrained type elimination, local variable lifting and partial function elimination. We explain our approach in the context of the modelling language Zinc. An implementation of it is an integral part of our Zinc compiler
Branch-and-Price Solving in G12
The G12 project is developing a software environment for stating and solving combinatorial problems by mapping a high-level model of the problem to an efficient combination of solving methods. Model annotations are used to control this process.
In this paper we explain the mapping to branch-and-price solving. G12 supports the selection of specialised subproblem solvers, the aggregation of identical subproblems, automatic disaggregation when required by search, and the use of specialised branching rules. We demonstrate the benefits of the G12 framework on three examples: a trucking problem, cutting stock, and two-dimensional bin packing
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