International Journal of Information Technology & Decision Making

Space-time block (STB) coding has been an effective transmit diversity technique for combating fading recently. In this paper, a full-rate and low-complexity STB coding scheme with complex orthogonal design for multiple antennas is proposed, and turbo code is employed as channel coding to improve the proposed code scheme performance further. Compared with full-diversity multiple antennas STB coding schemes, the proposed scheme can implement full data rate, partial diversity and a smaller complexity, and has more spatial redundancy information. Moreover, using the proposed scheme can form efficient spatial interleaving, thus performance loss due to partial diversity is effectively compensated by the concatenation of turbo coding. Simulation results show that on the condition of the same system throughput and concatenation of turbo code, the proposed scheme has lower bit error rate (BER) than those low-rate and full-diversity multiple antennas STB coding schemes.

A common problem in mining association rules or sequential patterns is that a large number of rules or patterns can be generated from a database, making it impossible for a human analyst to digest the results. Solutions to the problem include, among others, using interestingness measures to identify interesting rules or patterns and pruning rules that are considered redundant. Various interestingness measures have been proposed, but little work has been reported on the effectiveness of the measures on real-world applications. We present an application of Web usage mining to a large collection of Livelink log data. Livelink is a web-based product of Open Text Corporation, which provides automatic management and retrieval of different types of information objects over an intranet, an extranet or the Internet. We report our experience in preprocessing raw log data, mining association rules and sequential patterns from the log data, and identifying interesting rules and patterns by use of interestingness measures and some pruning methods. In particular, we evaluate a number of interestingness measures in terms of their effectiveness in finding interesting association rules and sequential patterns. Our results show that some measures are much more effective than others.

From an information systems perspective, the assessment of commercial websites can be assessed objectively or subjectively. From a business point of view, they can be assessed quantitatively or qualitatively. This paper describes taxonomy of website assessment approaches and proposes a knowledge-based system approach to evaluate commercial websites effectively. Given a large number of constantly evolving commercial websites on the Internet, our approach shows an efficient way of automatic assessment of commercial websites.

As more and more consumer-to-consumer e-marketplaces have been introduced with rapidly increasing transaction volumes, consumers now hope that computer technology will support their transaction processes in these electronic markets. To satisfy their expectations, many researchers have delved into developing intelligent agent systems to support customer-to-customer electronic commerce more efficiently. However, many of these researchers have focused only upon supporting simple negotiation for the price of undifferentiated goods. To expand the object of negotiation to differentiated goods, customers should be allowed to negotiate over multiple attributes of the product besides the price, including attributes which are related to the transaction activity itself, such as delivery time and payment method. To satisfy this requirement, we propose an agent marketplace for differentiated goods where the agent of a customer can negotiate not only for the price but also various attributes of a product and transaction in order to provide a better utility level for both buyer and seller. To achieve these goals, we have developed a formal protocol and system architecture to support the proposed e-marketplace and individual agents, and a prototype system is developed to validate our approach and show that negotiation resulting from our scheme is Pareto optimal.

This study investigates the trends followed by MVNOs (Mobile Virtual Network Operators) in the last three years and analyzes the strategies that can contribute to the success of Taiwan's telecommunications industry and marketing. We apply the method and concept of PATTERN (Planning Assistance Through Technical Evaluation of Relevance Number) to establish relevant systems for searching out the key successful factors of strategies to attract MVNOs. We also use the fuzzy Multi-Criteria Decision Making (MCDM) method for analyzing the different preference of a decision group in the criteria weights and for ranking the alternatives in a fuzzy environment in order to provide a strategy scheme. These results provide a reference to assist telecommunications operators, 3G license owners, potential MVNOs, and equipment manufacturers when working out business plans.

Artificial neural networks (ANNs) have been widely applied to finance and economic forecasting as a powerful modeling technique. By reviewing the related literature, we discuss the input variables, type of neural network models, performance comparisons for the prediction of foreign exchange rates, stock market index and economic growth. Economic fundamentals are important in driving exchange rates, stock market index price and economic growth. Most neural network inputs for exchange rate prediction are univariate, while those for stock market index prices and economic growth predictions are multivariate in most cases. There are mixed comparison results of forecasting performance between neural networks and other models. The reasons may be the difference of data, forecasting horizons, types of neural network models and so on. Prediction performance of neural networks can be improved by being integrated with other technologies. Nonlinear combining forecasting by neural networks also provides encouraging results.

This article studies the market reaction surrounding the announcement of the convertible bonds issuance in Chinese market, and partly explains the difference of influence on underlying securities in mature market such as the US market and emerging market in China. Meanwhile, it reveals how insiders in Chinese market use convertible bonds as a tool to manage the expected return of external investors.

This paper studies a supply chain consisting of two suppliers and an assembler who also acts as a retailer in a single period model. The suppliers provide complementary modules to the assembler and the latter assembles the final products and sells them to meet a stochastic demand. Each supplier can improve his performance by offering a return policy to the assembler while the best contract depends on that offered by the other supplier. We show that the non-cooperative contracts game between the firms has a unique and stable equilibrium in which the optimal return policies happen to fully coordinate the whole channel. Moreover, the suppliers still have the rights to negotiate with the assembler independently to share their profits properly. With such properties, the suppliers are encouraged to offer return policies to the assembler by following a simple rule derived from the favorable equilibrium, which will lead to a win-win-win situation.

This paper describes a methodology for handling the propagation of uncertainty in the analytic hierarchy process (AHP). In real applications, the pairwise comparisons are usually subject to judgmental errors and are inconsistent and conflicting with each other. Therefore, the weight point estimates provided by the eigenvector method are necessarily approximate. This uncertainty associated with subjective judgmental errors may affect the rank order of decision alternatives. A new stochastic approach is presented to capture the uncertain behavior of the global AHP weights. This approach could help decision makers gain insight into how the imprecision in judgment ratios may affect their choice toward the best solution and how the best alternative(s) may be identified with certain confidence. The proposed approach is applied to the example problem introduced by Saaty for the best high school selection to illustrate the concepts introduced in this paper and to prove its usefulness and practicality.

Quality consultants are used in ISO 9000 implementation projects especially by many small and medium-sized enterprises. Clients do not always appreciate differences between quality consultants. This paper aims to provide an analytical tool to select the best quality consultant providing the most customer satisfaction. The clients of three Turkish quality consultancy firms were interviewed and the most important criteria taken into account by the clients while they were selecting their consultancy firms were determined by a designed questionnaire. The fuzzy analytic hierarchy process was applied to compare these consultancy firms. The means of the triangular fuzzy numbers produced by the customers and experts for each comparison were successfully used in the pair wise comparison matrices.