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For any n-bit boolean function f, we show that the randomized communication complexity of the composed function f o g^n, where g is an index gadget, is characterized by the randomized decision tree complexity of f. In particular, this means that many query complexity separations involving randomized models (e.g., classical vs. quantum) automatically imply analogous separations in communication complexity.
We consider questions that arise from the intersection between theareas of approximation algorithms, subexponential-time algorithms, and fixed-parameter tractable algorithms. The questions, which have been asked several times (e.g., [Marx, 2008; Fellow et al., 2012; Downey & Fellow 2013]) are whether there is a non-trivial FPT-approximation algorithm for the Maximum Clique (Clique) and Minimum...
We study the two-dimensional geometric knapsack problem (2DK) in which we are given a set of n axis-aligned rectangular items, each one with an associated profit, and an axis-aligned square knapsack. The goal is to find a (non-overlapping) packing of a maximum profit subset of items inside the knapsack (without rotating items). The best-known polynomial-time approximation factor for this problem (even...
We study the computational complexity of short sentences in Presburger arithmetic (SHORT-PA). Here by short we mean sentences with a bounded number of variables, quantifiers, inequalities and Boolean operations; the input consists only of the integer coefficients involved in the linear inequalities. We prove that satisfiability of SHORT-PA sentences with m+2 alternating quantifiers is SigmaP_m-complete...
We provide a combinatorial characterization of all testable properties of k-graphs (i.e. k-uniform hypergraphs). Here, a k-graph property P is testable if there is a randomized algorithm which makes a bounded number of edge queries and distinguishes with probability 2/3 between k-graphs that satisfy P and those that are far from satisfying P. For the 2-graph case, such a combinatorial characterization...
In this paper we introduce the notion of lockable obfuscation. In a lockable obfuscation scheme there exists an obfuscation algorithm Obf that takes as input a security parameter, a program P, a message msg and lock value lck and outputs an obfuscated program oP. One can evaluate the obfuscated program oP on any input x where the output of evaluation is the message msg if P(x) = lck and otherwise...
Diagrams can be an effective means of communicating complex ideas and can aid ontology engineering. Indeed, domain experts often do not have the expertise required to understand or create the complex logical statements of an ontology in description logic (DL). This paper presents a visualisation method, concept diagrams, geared toward expressing assertions and class expression axioms alongside providing...
Spreadsheets serve as a basis for decision-making processes in many companies and bugs in spreadsheets can therefore represent a considerable risk to businesses. Systematic tests can help to locate such bugs, but providing test cases can be cumbersome and complex for large real-world spreadsheets. To make the specification of test cases easier, we propose to split spreadsheets into smaller logically...
Spreadsheets are used in professional business contexts to make decisions based on collected data. Usually, these spreadsheets are developed by end users in an ad-hoc way. Thus, the business logic of a concrete spreadsheet is not explicit to end users, making its correctness hard to assess and users have to trust. We present an approach where structure and computational behavior of a spreadsheet are...
Multi-objective optimization plays an important role when one has fitness functions that are somehow conflicting with each other. Also, parameter-dependent machine learning techniques can benefit from such optimization tools. In this paper, we propose a multi-objective-based strategy approach to build compact though representative training sets for Optimum-Path Forest (OPF) learning purposes. Although...
This work in progress report demonstrates a novel approach for behavioral augmentations in Virtual Reality (VR). Using a large scale tracking system, groups of five users explored a virtual museum. We investigated how augmenting social interactions impacts this experience, by designing behavioral transformations for behavioral phenomena in social interactions. Preliminary data indicate a reduction...
Process-aware Information Systems (PAIS) have become ubiquitous in companies. Thus the amount of data that can be used to analyze and monitor process executions is vast. The event logs generated by PAIS might contain information about decision making processes and can support the understanding and improving of procedures in companies. Mining decisions and constraints from logs has already been investigated,...
This paper presents ARial Texture: which is a drone display with dynamic projection mapping on the drone's propellers. In our prototype, a motion capture system tracks the drone's position and orientation and a projector projects an image on the drone's four propellers. To evaluate the visibility of the display, we conducted quantitative and qualitative experiments in which the propellers were covered...
Social engineering has emerged as a serious threat in virtual communities and is an important means to attack information systems. The services used by today's knowledge workers prepare the base for complicated social engineering attacks. Phishing is a kind of technically generated social engineering attack and is the type of identity theft that uses the social engineering techniques and complex attack...
With the widespread usage of information and communication technologies rapidly and the increase in data storage and transformation electronically it is very important to provide personal data security and raising security awareness in public. One of the most problematic issues about information technologies are the ones relating with personal and vital data security. Within the context of this study...
In this paper, we introduce HoloBee, a visual analytics system that enables end users to analyse bee drift data using HoloLens as a head mounted augmented reality interface. HoloBee was designed to allow for interactive exploration of bee behaviour and specifically bee drift: the phenomenon of a bee leaving a hive and returning to another hive. For exploration in the bees' natural environment, bee...
Augmented reality (AR) systems allow enriching the environment by supportive and useful virtual data. However, the human information processing capacity is limited. Thus, additional information may distract attention from the environment to the virtual data, resulting in a lower perception of relevant real-world information. In this paper we evaluate whether this effect depends on the frame of reference...
Modular medium voltage power converters have gained increasing attention in context of Smart Transformers (STs) in the electrical distribution grid. A possible ST architecture can be built by a Cascaded H-Bridge (CHB) converter in the Medium Voltage side and Dual Active Bridges (DABs) in the isolation stage. One of the main issues in the CHB control is represented by the voltage balancing. This work...
The vision is considered the most important sense in humans, the visual field may be affected by various diseases or conditions that can even be congenital, resulting in a high percentage of people with visual problems, low vision to blindness. In the majority of cases can be corrected with conventional methods, however, if a suitable control could be prevented and up to early detection of various...
Recently, various objective image quality assessment (IQA) metrics have been proposed for measuring the quality of a captured image. Moreover, IQA databases have been made available to enable researchers develop and test IQA metrics. For instance, the TID2013 database was used in the experiments conducted in this study. It contains many test images obtained from 25 reference images, each having 24...
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