Equality to equals and unequals: a revisit of the equivalence and nonequivalence criteria in object-oriented software testing

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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