13,053 research outputs found
Equality to equals and unequals: a revisit of the equivalence and nonequivalence criteria in object-oriented software testing
published_or_final_versio
Automated Hierarchical Image Segmentation Based on Merging of Quadrilaterals
Proceedings of the 6th WSEAS International Conference on Signal Processing, Computational Geometry & Artifical Vision, 2006, p. 135-140This paper proposes a quadrilateral-based and automated hierarchical segmentation method, in which quadrilaterals are first constructed from an edge map, where neighboring quadrilaterals with similar features of interest are then merged together in a hierarchical mode to form regions. When evaluated qualitatively and quantitatively, the proposed method outperforms three traditional and commonly-used techniques, namely, K-means clustering, seeded region growing and quadrilateral-based segmentation. It is shown by experimental results that our proposed method is robust in both recovering missed important regions while preventing unnecessary over-segmentation, and offers an efficient description of the segmented objects conducive to content-based applications.postprintThe 6th WSEAS International Conference on Signal Processing, Computational Geometry & Artificial Vision (ISCGAV'06), Crete, Greece, August 2006. in Conference Proceedings, 2006, p. 135-14
Transformation of UML interaction diagrams into contract specifications for object-oriented testing
Testing is an important means to ensure the quality of software systems. Contract specification can be used to formally specify the cluster level of object-oriented software, which can then be tested using TACCLE, an advanced methodology for object-oriented testing. The use of formal specifications as a testing base has many advantages. However, such specifications are not easily understood and therefore not widely used in the software industry. On the other hand, UML, a semi-formal modeling language, is becoming increasingly popular and widely accepted. In particular, UML interaction diagrams specify the dynamic, interacting behavior among the objects of an object-oriented system. If the transformation of UML interaction diagrams into Contract specifications can be automated, the TACCLE methodology can be applied directly to test object-oriented software at the cluster level. In this paper, a method to transform UML interaction diagrams into Contract specifications is proposed based on the UML meta-model. A prototype has been developed. © 2007 IEEE.published_or_final_versio
An invisibility cloak using silver nanowires
In this paper, we use the parameter retrieval method together with an
analytical effective medium approach to design a well-performed invisible
cloak, which is based on an empirical revised version of the reduced cloak. The
designed cloak can be implemented by silver nanowires with elliptical
cross-sections embedded in a polymethyl methacrylate host. This cloak is
numerically proved to be robust for both the inner hidden object as well as
incoming detecting waves, and is much simpler thus easier to manufacture when
compared with the earlier proposed one [Nat. Photon. 1, 224 (2007)].Comment: 7 pages, 4 figures, 2 table
Website Usability: A Re-Examination through the Lenses of ISO Standards
The original conceptualization of usability was ease of use, this was later expanded into a multi-dimensional construct in ISO standards and usability literature. Such an expansion is seen as an improvement, since cross-study comparison or benchmarking cannot objectively be done without a common set of usability components being defined. The current issue lies in how these components are operationalized, measured and validated. Although ISO standards ties usability to contextual situations, recent research has started to also recognize psychographic and demographic variations within the same context. The purpose of this study is to review web site usability as it relates to ISO standards (more specifically ISO 9126, ISO 9241 and ISO/IEC 25010) and existing usability studies. Implications for researchers and practitioners are provided
Game-Theoretic Approach to Tourism Supply Chain Coordination under Demand Uncertainty For Package Holidays
Demand uncertainty is one of the most significant characteristics of the tourism industry. In a typical tourism supply chain (TSC) for package holidays, multiple tour operators reserve rooms from a hotel chain in advance according to their demand predictions. Discrepancies between demand predictions and actual demand lead to shortages or unused room reservations, which inevitably leads to reduced profits for the tour operators concerned. This article examines different TSC coordination strategies to determine how they can be used to help alleviate such negative effects. A game-theoretic approach is used to analyze the different coordination relationships between TSC players. Two coordination programs are discussed. The first is a horizontal coordination program in which tour operators exchange shortages or unused reservations with each other. The second is a vertical coordination program in which tour operators trade shortages or unused reservations with hotel chains. Game models are established and analyzed for the two coordination strategies and uncoordinated conditions, respectively. The analytical results suggest that both coordination strategies can be used to reduce the negative impacts of the demand uncertainty. The results also show that the horizontal coordination is preferred to the vertical coordination when the competition among tour operators is fierce.published_or_final_versio
On the Connection Between MPNN and Graph Transformer
Graph Transformer (GT) recently has emerged as a new paradigm of graph
learning algorithms, outperforming the previously popular Message Passing
Neural Network (MPNN) on multiple benchmarks. Previous work (Kim et al., 2022)
shows that with proper position embedding, GT can approximate MPNN arbitrarily
well, implying that GT is at least as powerful as MPNN. In this paper, we study
the inverse connection and show that MPNN with virtual node (VN), a commonly
used heuristic with little theoretical understanding, is powerful enough to
arbitrarily approximate the self-attention layer of GT.
In particular, we first show that if we consider one type of linear
transformer, the so-called Performer/Linear Transformer (Choromanski et al.,
2020; Katharopoulos et al., 2020), then MPNN + VN with only O(1) depth and O(1)
width can approximate a self-attention layer in Performer/Linear Transformer.
Next, via a connection between MPNN + VN and DeepSets, we prove the MPNN + VN
with O(n^d) width and O(1) depth can approximate the self-attention layer
arbitrarily well, where d is the input feature dimension. Lastly, under some
assumptions, we provide an explicit construction of MPNN + VN with O(1) width
and O(n) depth approximating the self-attention layer in GT arbitrarily well.
On the empirical side, we demonstrate that 1) MPNN + VN is a surprisingly
strong baseline, outperforming GT on the recently proposed Long Range Graph
Benchmark (LRGB) dataset, 2) our MPNN + VN improves over early implementation
on a wide range of OGB datasets and 3) MPNN + VN outperforms Linear Transformer
and MPNN on the climate modeling task
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