Journal:Informatica
Volume 34, Issue 1 (2023), pp. 53–83
Abstract
Innovation can be the greatest hope of overcoming economic challenges. This paper aims to evaluate countries concerning their innovation performances. We introduce an innovation performance evaluation methodology by considering objective factors and applying seven reliable MCDM methods: MEREC, CODAS, MABAC, MARCOS, CoCoSo, WASPAS, and MAIRCA. MEREC calculates the relative weights of indicators considered, while the other techniques decide the ranking order of G7 countries. The Borda rule is then employed to gain an aggregated ranking order. “Business sophistication” is the most critical indicator, whereas the US has the best position regarding the overall ranking. Sensitivity control is as well conducted.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 30, Issue 2 (2019), pp. 327–348
Abstract
In our previous paper we presented an offline e-cash system with observers. We have shown that the proposed system satisfies basic requirements for e-cash schemes. We also covered such security issues as chosen message attack resistance and forgery of protocols data. However, in that paper we focused more on the system itself, rather than its analysis.
Hence, here we present cryptanalysis of our system. We aim to prove that existential forgery of data is not possible due to complexity of the discrete logarithm problem. Furthermore, we perform the analysis of trustworthiness of the system using the so-called BAN logic. Also, we consider effectivity of the proposed e-cash system in observers with limited computational resources.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 295–312
Abstract
Software size is an important attribute in software project planning. Several methods for software size estimation are available; most of them are based on function points. Albrecht introduced function points as a technologically independent method with its own software abstraction layer. However, it is difficult to apply original abstraction elements to current technologies. Therefore researchers introduced additional rules and mappings for object-based solutions. In this paper several mapping strategies are discussed and compared. Based on the similarities in compared mappings, a common mapping strategy is then defined. This mapping is then tested on the reference application portfolio containing five applications. The aim of the test scenario is to evaluate the impact of the diverse detail levels in the class diagrams on software size measurement. Although the question of how to perform quality size measurements in object-oriented projects remains unanswered, the paper gives valuable information on the topic, supported by mathematics.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 30, Issue 2 (2019), pp. 293–325
Abstract
The Hamy mean (HM) operator, as a convenient mathematical aggregation tool, can deal with the interrelationship among multiple input parameters, and the power average (PA) operator can relieve the influence of awkward assessment values in the decision consequences. The interval neutrosophic sets (INSs) are a more powerful mathematical tool to handle insufficient, indeterminate and vague information that exists in real life problems. Yet, in some complicated decision-making situations, we require to consider the correlation between multi-input arguments and remove the influence of awkward data at the same time. To deal with such situations, in this paper, we combine the conventional HM operator to the traditional PA operator in interval neutrosophic settings and present two novel interval neutrosophic aggregation operators, that is, the interval neutrosophic power Hamy mean (INPHM) operator and the weighted interval neutrosophic power Hamy mean (WINPHM) operators. Then, some preferable properties of the developed aggregation operators are discussed. Moreover, based on these developed aggregation operators, we propose a new method for multiple attribute group decision making (MAGDM) under the INSs. Lastly, some examples are given to show the effectiveness of the developed method by comparing it with other existing methods.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 285–294
Abstract
Recently, Yang et al. proposed an improvement to Tseng et al.’s protected password changing scheme that can withstand denial of service attack. However, the improved scheme is still susceptible to stolen-verifier attack and denial of service attack. Accordingly, the current paper demonstrates the vulnerability of Yang et al.’s scheme to two simple attacks and presents an improved protected password change scheme to resolve such problems. In contrast to Yang et al.’s protected password changing scheme and the existing password change schemes using server’s public key, the proposed scheme can securely update user passwords without a complicated process and server’s public key.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 275–284
Abstract
Recently, Tzeng proposed a provably secure and fault-tolerant conference-key agreement protocol. It requires only a constant number of rounds to establish a conference key among all honest participants. This article will show that Tzeng’s protocol does not offer forward secrecy. We say that a conference-key agreement protocol offers forward secrecy if the long-term secret key of any participant is compromised and will not result in the compromise of the previously established conference keys. This property is important and has been included in most key agreement protocols and standards. In this paper, an improvement based on Tzeng’s protocol is proposed and it achieves forward secrecy. Under the Diffie–Hellman decision problem assumption and the random oracle model, we show that the proposed protocol can withstand passive attacks and is secure against impersonator’s attacks. The improved protocol requires a constant number of rounds to compute a conference key. The improved protocol provides fault-tolerance.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 261–274
Abstract
Since threshold proxy signature has been proposed, all threshold proxy signature schemes are based on the discrete logarithm problems in the modular multiplicative group which has an element g with a large prime order. Nowadays this kind of threshold proxy signature schemes become more and more complex and time-consuming for security and specific requirement. In this paper, we propose a (bilinear) pairing-based threshold proxy signature scheme with known signers, analyze its security and check the following properties the proposed scheme has: non-repudiation, unforgeability, identifiability, distinguishability, verifiability, prevention of misuse of proxy signing right, etc. Moreover, we point out that the proposed scheme is of great efficiency by comparing it with Sun’s and Hsu et al.’s scheme.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 241–260
Abstract
Tele-Collaboration will enable users in different locations to collaborate in a shared, simulated environment as if they were in the same physical room. It’s the ultimate synthesis of networking and media technologies to enhance collaborative environments. When participants are Tele-Collaborated, they are able to interact with each other in a shared virtual environment. They are able to query and visualize data stores and steer complex scientific and engineering simulations. This article investigated the transcoding intermediaries required to achieve an effective telecollaboration on the Web as well as on P2P/Grid environments. Both Scene Graphs as used by the virtual SceneBeans and the SVG DOM tree are found to be essential for the transcoding purpose.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 213–240
Abstract
The article describes a hierarchical decision making framework for the evaluation and improvement/redesign of composite systems. The framework is based on Hierarchical Morphological Multicriteria Design (HMMD) and corresponding morphological clique problem which realize “partitioning/synthesis macroheuristic”. The system evaluation process consists in hierarchical integration of expert judgment (as ordinal estimates): a method of integration tables or the above-mentioned morphological approach. As a result, ordinal multi-state classification is realized. The system improvement/redesign process is examined as the selection and planning of redesign operations while taking into account operations attributes (e.g., required resources, effectiveness) and binary relations (equivalence, complementarity, precedence) on the operation sets. For modeling the system improvement process several combinatorial optimization models are used (knapsack problem, multiple choice problem, etc.) including HMMD.
The suggested approach is illustrated by realistic numerical example for two-floor building. This applied problem is examined from the viewpoint of earthquake engineering.
Pub. online:5 Aug 2022Type:Research ArticleOpen Access
Journal:Informatica
Volume 16, Issue 2 (2005), pp. 203–212
Abstract
In 2001, Tseng, Jan, and Chien proposed an improved version of Peyravian–Zunic’s password authentication scheme based on the Diffie–Hellman scheme. Later, Yang, Chang, and Hwang demonstrated that Tseng–Jan–Chien’s scheme is vulnerable to a modification attack, and then described an improved scheme. In this paper, we show that Yang–Chang–Hwang’s scheme is still vulnerable to a denial-of-service attack and a stolen-verifier attack. In addition, we also propose an improved scheme with better security.