No. 4 (2008)
Published:
2008-12-30
ARTICLES FROM THIS ISSUE
-
Delays in Technology Development: Their Impact on the Issues of Determinism, Autonomy and Controllability of Technology
Abstract
The paper provides a discussion of diverse delays occurring in technology development, and an explanation of reasons why, when seen holistically from outside, the process of technology development might appear as an autonomous, self-determining, uncontrollable process. When seen from inside, however, the process is far from being uncontrollable. This paradox is explained by the fact that technology development contains many processes with delays, in total amounting sometimes to fifty years; when seen from outside, such a process might appear uncontrollable, even if it is very much controllable when approached internally and in detail. Therefore, the definition and types of technology creation as well as stages of technological processes are discussed in some detail in this paper. Some aspects of the contemporary informational revolution and some recent results on micro-theories of knowledge and technology creation are also reviewed. It is suggested that one of possible ways of changing the paradigmatic attitude of philosophy of technology is to invite some such philosophers to participate in the development of modern tools of knowledge civilization era, such as software development and evaluation. The conclusions of the paper stress the need of essentially new approaches to many issues in the time of informational revolution.
-
Reference Point Method with Importance Weighted Partial Achievements
Abstract
The reference point method (RPM) is based on the so-called augmented max-min aggregation where the worst individual achievement maximization process is additionally regularized with the average achievement. In order to avoid inconsistencies caused by the regularization, we replace it with the ordered weighted average (OWA) which combines all the individual achievements allocating the largest weight to the worst achievement, the second largest weight to the second worst achievement, and so on. Further following the concept of the weighted OWA (WOWA) we incorporate the importance weighting of several achievements into the RPM. Such a WOWA RPM approach uses importance weights to affect achievement importance by rescaling accordingly its measure within the distribution of achievements rather than by straightforward rescaling of achievement values. The recent progress in optimization methods for ordered averages allows us to implement the WOWA RPM quite effectively as extension of the original constraints and criteria with simple linear inequalities.
-
On Subjective Trust Management
Abstract
Trust and reputation management is gaining nowadays more attention then ever as online commodity exchange and other open virtual societies became a widespread reality. Most widely used computational models use reputation metrics as global property assigned to each party. More sophisticated models try to use reputation as subjective property. While introducing subjective reputation there arise a need to model preferences of agents. In this paper we propose to use weighted ordered weighted average (WOWA) operator to support the decision maker in assessing available evidence about other’s party behavior. The WOWA aggregation is defined by two weighting vectors: the preferential weights assigned to the ordered quantities and the importance weights assigned to several attributes. It allows one to express both the preference regarding sources of information by the corresponding importance weights and the compensation between attribute values aggregated by the preferential weights.
-
An Eclectic Approach to Network Service Failure Detection Based on Multicriteria Analysis with an Example of Mixing Probabilistic Context Free Grammar Models
Abstract
A method of failure detection in telecommunication networks is presented. This is a meta-method that correlates alarms raised by failure-detection modules based on various philosophies. The correlation takes into account two main characteristics of each module and the whole metamethod: the percentage of false alarms and the percentage of omitted failures. The trade-off between them is tackled with aspiration-based multicriteria analysis. The alarms are cor- related using linear classification by support vector machines. An example of the profitability of correlating alarms in such way is shown. This is an example of probabilistic context free grammars (PCFGs), used to model the proper runtime paths of network services (and thus usable for detecting an improper behavior of the services). It is shown that the linearly mixing PCFGs can add context handling to the PCFG model, thus augmenting the capabilities of the model.
-
A Level-Based Approach to Prioritize Telecommunications R&D
Abstract
In this paper, an approach to evaluate R&D projects in telecommunications is presented. These projects have particular features that cannot be properly incorporated by classical evaluation methods. This approach incorporates different criteria, both quantitative and qualitative, and also management flexibility and uncertainty. Thus, it is an approach that can be applied to real data of R&D projects in a telecommunications company.
-
Ontology Creation Process in Knowledge Management Support System for a Research Institute
Abstract
Though the issue of knowledge management is a hot subject of interest in nowadays market companies, integrated solutions fit to the specific needs of research institutes still require more attention. This paper documents a part of the research activities performed at National Institute of Telecommunications, related to development of research institute knowledge management support system. The ideas lying in the background of the system come from the recent theories of knowledge creation and creativity support and from experience with everyday practice of knowledge management in market companies. Main focus is put here on the issue of creation of a research topics ontology that is meant to be a semantic backbone of the system. Three-stage approach is proposed, aiming at the construction of ontologies for different levels of organizational hierarchy, from individual researcher, through group or unit, up to the whole institute. Created ontologies are linked to knowledge resources and support diverse activities performed at those levels
-
Towards a Unified Architecture of Knowledge Management System for a Research Institute
Abstract
This paper presents some elements of architecture of planned knowledge management system dedicated to research institutions. Main contributions include social extension of the idea of adaptive hermeneutic agent and preliminary implementation of domain specific language for development of knowledge management systems. Work described here concentrated on practical verification of viability of proposed ideas and took form of a prototype software system, which can be used by a group of researchers to easily find and recommend relevant information
-
Multicommodity Auction Model for Indivisible Network Resource Allocation
Abstract
In this paper we present the multicommodity auction model BCBT-I that allocates indivisible network resources among bidders. The approach can be considered as a generalization of the basic multicommodity model for balancing communication bandwidth trade (BCBT). The BCBT model assumes that offers concerning inter-node links and point-to-point bandwidth demands can be realized partially. However, in the real-world trade there might be a need to include ca- pacity modularity in the market balancing process. Thus we state the model for balancing communication bandwidth trade that takes into account the indivisibility of traded bandwidth modules. This requires to solve a mixed integer problem and increases computational complexity. Furthermore, the pricing issue appears nontrivial, as the dual prices cannot be longer used to set fair, competitive market prices. For clearing the market, we examine the multicommodity pricing mechanism based on differentiation of buy and sell market prices
-
Spectral Division of the Optical Fiber Passband Using Narrowband Controllable Filter on the Base of Semiconductor Waveguide Microresonator
Abstract
We analyze the new principle of multichannel spectral division of optical fiber passband using controllable narrowband integrated optical filters composed of two-coupled ring microresonators made of different semiconductor materials. It is shown that appropriate selecting the semiconductor material and optimizing the design factors of selective optical element allows creating the simple and economical integrated optical filter with bandwidth 0.1 nm, frequency separation between adjacent optical carriers 0.2 nm and signal-to-noise ratio 50 dB. Utilizing such filters in optical fiber communication lines makes it possible to increase the number of transmitted in parallel optical carrier wavelengths up to 160 and even more, i.e., to provide the traffic transmission with the speed up to 1.6 Tbit/s in one direction and in single optical fiber
-
On the Effects of Code Cardinality for TH-PPM Ultra Wideband Systems
Abstract
This paper demonstrates the effects of code cardinality at transmitter section on bit error rate (BER) performance of time hopping pulse position modulation (TH-PPM) based ultra wideband (UWB) indoor radio communication. In the transmitter, different code cardinality values have been chosen and correspondingly the effects on BER of the system have been investigated. The recently accepted IEEE 802.15.3a model of the UWB channel has been used as the propaga- tion channel model in indoor environment. Results show that the system BER performance is significantly dependent on the code cardinality value of time hopping code. For such higher code cardinality values as in the range from 30 to 50, the BER performance degrades severely. Finally, code cardinality in the range from 10 to 15 has been recommended for TH-PPM system in UWB indoor communications providing better BER performance for the same system data rate requirement
-
High-Frequency Power Amplitude Modulators with Class-E Tuned Amplifiers
Abstract
A high-frequency power amplifier used in a drain amplitude modulator must have linear dependence of output HF voltage Vo versus its supply voltage VDD. This condition essential for obtaining low-level envelope distortions is met by a theoretical class-E amplifier with a linear shunt capacitance of the switch. In this paper the influence of non-linear output capacitance of the transistor in the class-E amplifier on its Vo(VDD) characteristic is analyzed using PSPICE simulations of the amplifiers operating at frequencies 0.5 MHz, 5 MHz and 7 MHz. These simulations have proven that distortions of theVo(VDD) characteristic caused by non-linear output capacitance of the transistor are only slight for all analyzed amplifiers, even for the 7 MHz amplifier without the external (linear) shunt capacitance. In contrast, the decrease of power efficiency of the class-E amplifier resulting from this effect can be significant even by 40%
-
Cooperative and Non-cooperative, Integrative and Distributive Market Games with Antagonistic and Altruistic, Malicious and Kind Ways of Playing
Abstract
The article illustrates distinctions between important concepts of game theory, which support understanding the relation between subjects on competitive and regulated telecommunications services market. Especially it shows that often used distinction between retail and wholesale market that treat them respectively as competitive and cooperative can be misleading or even wrong
-
Problems of Broadband in Rural Areas in Light of the BReATH Project Experiences
Abstract
Some lessons learned from the EU project “Broadband e-Services and Access to the Home” (2005–2007) are presented concerning the broadband development in rural ar- eas. In particular, the paper discusses the common problems of broadband deployment in the rural environment, various aspects of stimulating demand for broadband, the limitations of public aid and, most importantly, the problems of technoeconomic analysis
