Search results for "opera"
showing 10 items of 8665 documents
A Cooperative Coevolution Framework for Parallel Learning to Rank
2015
We propose CCRank, the first parallel framework for learning to rank based on evolutionary algorithms (EA), aiming to significantly improve learning efficiency while maintaining accuracy. CCRank is based on cooperative coevolution (CC), a divide-and-conquer framework that has demonstrated high promise in function optimization for problems with large search space and complex structures. Moreover, CC naturally allows parallelization of sub-solutions to the decomposed sub-problems, which can substantially boost learning efficiency. With CCRank, we investigate parallel CC in the context of learning to rank. We implement CCRank with three EA-based learning to rank algorithms for demonstration. E…
Shared and personal learning spaces: Challenges for pedagogical design
2012
Abstract The development of new tools for collaboration, such as social software, plays a crucial role in leisure time and work activities. The aim of this article is to summarize the research in the field of computer-supported collaborative learning (CSCL). This is done particularly from the perspective of the blurred line between individual (personal) and group-level (shared) learning that the use of the new tools has forced us to re-think. First, individual and group-level perspectives to learning are discussed to make sense of the major notions of how learning is understood in CSCL research. Second, based on this theoretical grounding, it will be further elaborated what this means to th…
Wastewater treatment: New insight provided by interactive multiobjective optimization
2011
In this paper, we describe a new interactive tool developed for wastewater treatment plant design. The tool is aimed at supporting the designer in designing new wastewater treatment plants as well as optimizing the performance of already available plants. The idea is to utilize interactive multiobjective optimization which enables the designer to consider the design with respect to several conflicting evaluation criteria simultaneously. This is more important than ever because the requirements for wastewater treatment plants are getting tighter and tighter from both environmental and economical reasons. By combining a process simulator to simulate wastewater treatment and an interactive mul…
E-NAUTILUS: A decision support system for complex multiobjective optimization problems based on the NAUTILUS method
2015
Interactive multiobjective optimization methods cannot necessarily be easily used when (industrial) multiobjective optimization problems are involved. There are at least two important factors to be considered with any interactive method: computationally expensive functions and aspects of human behavior. In this paper, we propose a method based on the existing NAUTILUS method and call it the Enhanced NAUTILUS (E-NAUTILUS) method. This method borrows the motivation of NAUTILUS along with the human aspects related to avoiding trading-off and anchoring bias and extends its applicability for computationally expensive multiobjective optimization problems. In the E-NAUTILUS method, a set of Pareto…
How Do Mobile ICTs Enable Organizational Fluidity: Toward a Theoretical Framework
2017
Abstract The focus of this theoretical paper is to investigate how mobile information and communication technologies (ICTs) give rise to the notion of organizational fluidity. Drawing upon previous literature, five affordances of mobile ICTs − mobility, connectedness, interoperability, identifiability, and personalization − are discussed. Delving into the concept of organizational fluidity, the paper captures three dimensions of organizational fluidity, namely, team fluidity, task fluidity, and control fluidity. The paper then develops propositions on how different combinations of the mobile ICT affordances influence each of the dimensions of organizational fluidity. The contributions and i…
User experience targets as design drivers:A case study on the development of a remote crane operator station
2013
In recent years, the notion of user experience, or UX, as an essential aspect to be addressed in the design and development of technologies has been increasingly discussed. In this paper, we present a case study in which we have used UX targets as the main design drivers and focus areas in developing a new remote operator station user interface for container cranes. UX targets describe the experiential qualities to which the product design should aim at. However, taking UX targets into consideration during product design is challenging, because only little is known about how they would be best operationalized to serve the different phases of the design process. Through our case study, we de…
Role of Acquisition Intervals in Private and Public Cloud Storage Costs
2014
The volume of worldwide digital content has increased nine-fold within the last five years, and this immense growth is predicted to continue in the foreseeable future to reach 8 ZB by 2015. Traditionally, organizations proactively have built and managed their private storage facilities to cope with the growing demand for storage capacity. Recently, many organizations have instead welcomed the alternative of outsourcing their storage needs to the providers of public cloud storage services due to the proliferation of public cloud infrastructure offerings. The comparative cost-efficiency of these two alternatives depends on a number of factors, such as the prices of the public and private stor…
Linear fusion of interrupted reports in cooperative spectrum sensing for cognitive radio networks
2015
Interrupted reporting has recently been introduced as an effective method to increase the energy efficiency of cooperative spectrum sensing schemes in cognitive radio networks. In this paper, joint optimization of the reporting and fusion phases in a cooperative sensing with interrupted reporting is considered. This optimization aims at finding the best weights used at the fusion center to construct a linear fusion of the received interrupted reports, jointly with Bernoulli distributions governing the statistical behavior of the interruptions. The problem is formulated by using the deflection criterion and as a nonconvex quadratic program which is then solved for a suboptimal solution, in a…
Interactive Multiple Criteria Decision Making based on preference driven Evolutionary Multiobjective Optimization with controllable accuracy
2012
Abstract We present an approach to interactive Multiple Criteria Decision Making based on preference driven Evolutionary Multiobjective Optimization with controllable accuracy. The approach relies on formulae for lower and upper bounds on coordinates of the outcome of an arbitrary efficient variant corresponding to preference information expressed by the Decision Maker. In contrast to earlier works on that subject, here lower and upper bounds can be calculated and their accuracy controlled entirely within evolutionary computation framework. This is made possible by exploration of not only the region of feasible variants – a standard within evolutionary optimization, but also the region of i…
An Information Systems Design Product Theory for Integrated Requirements, Test and Defect Management Systems
2012
Software companies need to develop high-quality products fast and with low cost. Development activities are typically distributed in different places and involve multiple stakeholders in different countries. Testing is an important way to ensure product quality but it is costly and takes ample time and resources. Sourcing testing services from specialized service providers is often the most viable option for software businesses. Flexible and effective test process management is especially vital to support the testing life-cycle when external testing service providers are involved. Yet, the extant literature provides little theoretical guidance for managing the testing life-cycle, including …