Journal:Informatica
Volume 24, Issue 4 (2013), pp. 505–521
Abstract
Two mathematical models of an amperometric bienzyme biosensor are analysed digitally. The models hold different boundary conditions describing the singularity of the electrode (transducer). The influence of the initial and boundary conditions on the biosensors action at different sets of parameters is analysed.
The digital simulation at the transient and steady-state conditions was carried out by using finite difference technique. The comparison of the simulation results revealed that some of the calculated parameters, i.e. response and sensitivity is the same, while the others, i.e. half-time of the steady-state is significantly different for distinct models.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 523–542
Abstract
In this article, we propose a practical algorithm for capacitated facility location problems (CFLP). There are some approaches which can obtain primal solutions while simultaneously exploiting the primal structure and the dual structure. One of these approaches is the mean value cross decomposition (MVCD) method that ensures convergence without solving master problems. However, MVCD has been previously applied only to uncapacitated facility location problems (UFLP), due to the fact that the performance is highly dependent on the structure of the problem. The proposed algorithm, named the dynamic mean value cross decomposition algorithm (DMVCD), is effectively integrated with MVCD and cutting plane methods in order to tighten the bounds by reducing the duality gap. Computational results of various instances are also reported to verify the effectiveness and efficiency of DMVCD.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 543–560
Abstract
The symbiosis between an enterprise architecture and service-oriented architecture results in so-called service-oriented enterprise architecture and brings up new problems for service-oriented enterprise systems engineering. One of the most important is a business service quality definition, specification and evaluation. The paper proposes a formal model of enterprise business service quality evaluation framework to encompass and balance all the viewpoints and perspectives on an enterprise business service quality.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 561–576
Abstract
An Unequal Error Protection (UEP) scheme for image steganography is proposed in this paper. When stego images are transmitted through a noisy channel, the embedded message may be more sensitive to noise than the cover message. Therefore, we propose a Turbo UEP coding scheme for steganographic communication in a noisy channel, which provides higher error protection for the embedded message and lower error protection for the cover message. Simulations show that this coding scheme provides different error protection levels in one coding process and maintains the coding rate constant. In addition, an application scheme of the proposed Turbo UEP code for steganographic communication is presented, and the experimental results show that the extracted secret images have better quality than the cover images after decoding.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 577–602
Abstract
In this paper we focus on a specific class of XML schema inference approaches – so-called heuristic approaches. Contrary to grammar-inferring approaches, their result does not belong to any specific class of grammars and, hence, we cannot say anything about their features from the point of view of theory of languages. However, the heuristic approaches still form a wider and more popular set of approaches due to natural and user-friendly strategies. We describe a general framework of the inference algorithms and we show how its particular phases can be further enhanced and optimized to get more reasonable and realistic output. The aim of the paper is (1) to provide a general overview of the heuristic inference process and existing approaches, (2) to sum up the improvements and optimizations we have proposed so far in our research group, and (3) to discuss possible extensions and open problems which need to be solved. Hence, it enables the reader to get acquainted with the field fast.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 603–618
Abstract
Image synthesis techniques are present in a wide range of applications as they leverage the amount of information required for creating realistic visualizations. For fast hardware rendering they usually employ a triangle-based representation describing the geometry of the scene. In this paper, we introduce a new and simple framework for performing on-the-fly refinement and simplification of meshes completely on the GPU. As we aim at making easy the integration of level-of-detail management into the creation workflow of artists, the presented method is easy to be implemented. We only need a coarse mesh, its displacement map and a geometry shader. At rendering time, we employ a geometry shader to parallelize the tessellation and displacement steps. The tessellation step performs uniform refinement or simplification operations by applying a fixed subdivision criterion. Our method also exploits coherence by taking advantage of the last computed mesh. We provide a method which offers a flexible integration with standard 3D tools, easy to be implemented, coherence exploitation and wholly processed by the GPU.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 619–635
Abstract
“Strategy implementation” is an inseparable part of strategic management process. Transformation strategies to typical operations and daily functions of staff exert a significant role in organization success. Balanced scorecard (BSC) and strategy map help senior managers to perfectly implement and monitor the accomplishment of the strategies by transforming strategies into operational programs. Using BSC and strategy map, the strategies are translated into some action plans which help the achievement of organizational goals and strategies. Due to shortage of resources, usually all organization's action plans cannot be implemented completely; therefore, managers should make use of some tools for assigning and selecting more efective action plans. In this paper, a procedure is suggested on the basis of grey TOPSIS to determine the preference of action plans to better aid managers in selection of the most effective action plans in a group decision making process.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 637–656
Abstract
Underperformance in higher frequency signal regions denoising is a common problem for many denoising methods. Wavelet transforms are, generally, less prone to the problem than the pure spatial or frequency domain transforms, but there is still much room for improvements. In this paper, we propose a point-wise adaptive wavelet transform for signal denoising applications. It is very efficient in denoising higher frequency regions, without compromising the performance on smooth, lower frequency, regions. The transform uses statistical method of intersection of confidence intervals rule to adapt to local signal properties. Its performance was extensively tested on various signal classes. The results proved validity of theoretical assumptions and showed significant performance improvements when compared to other denoising methods.
Journal:Informatica
Volume 24, Issue 4 (2013), pp. 657–675
Abstract
In this paper, a modified version of the discrete wavelet transform (DWT), distinguishing itself with visibly improved space localization properties and noticeably extended potential capabilities, is proposed. The key point of this proposal is the full decorrelation of wavelet coefficients across the lower scales. This proposal can be applied to any DWT of higher orders (Le Gall, Daubechies D4, CDF 9/7, etc.). To open up new areas of practical applicability of the modified DWT, a novel exceptionally fast algorithm for computing the DWT spectra of the selected signal (image) blocks is presented. In parallel, some considerations and experimental results concerning the energy compaction property of the modified DWT are discussed.