The main purpose of the study was to compare four ability estimation engines (which are OWEN, EAP, MLE, and WLE) regarding the convergent state and divergent state, and dynamic behaviors under different types of test-taker's response pattern in CAT.

Information technologies have ushered in a new era for computer-related communications. Use of the Internet for commercial applications and resource sharing has accelerated in recent years as well. Owing to such developments, computer security has become a critical issue nowadays. In some applications, a critical message can be divided into pieces and allocated at several different sites over the Internet for security access concern. To access such an important message, one must access the divided pieces from different sites to reconstruct the message. In this paper, we propose model calculations to evaluate the probability of secret reconstruction and a weighted share assignment algorithm for assigning shares on hosts in such a way that the probability to be able to reconstruct the secret becomes the highest. Examples are presented to illustrate the feasibility of the proposed approach.

The WWW has become a powerful media for knowledge displacement and acquisitions for Internet users. For Internet content providers, the homepage is the common way to let users know where the contents are placed. Currently, there are many homepage design tools available for content providers to make their Web pages, FrontPage Express, Flash, HotDog, to name a few. While making an animated multimedia homepage, most of these design tools have to use their extended programming features such as combing part of the code of JavaScript, or Java program to achieve this goal. For general users, especially for the non-computer professional users, to write Java programs to make an animated multimedia homepage is not an easy job. In this paper, a visual authoring system for general users to make an animated multimedia homepage is proposed. Based on this tool, users can create an animated multimedia homepage at their fingertips without writing any program or code. The proposed authoring tool has been technology transferred to the Best Wise International Computing Cooperation for product development. Examples shown in this paper are created based on the WebFace Maker (a product of the Best Wise International Computing Co.) which is a product developed using the proposed technology.

Multimedia electronic books play an important role now as the demand for creative education is becoming a major trend in elementary schools. Although the textual scripting languages can describe powerful scenarios, users must be skilled with programming ability in order to create multimedia electronic books. For common users such as elementary school teachers, it may not be an easy job for them to produce multimedia electronic books. Thus, innovative ways to create multimedia electronic books must be requested. We propose a visual scenario construction language for electronic books. Using the proposed visual construction approach, one can create animated pictures or motion pictures and use it to describe a presentation scenario instead of writing a large mass of textual programs. Based on the proposed approach, an interactive multimedia electronic book can be produced relatively easy compared with the use of traditional approaches.

The problem of allocating high-volume multimedia files on a virtual circuit network with the objective of maximizing channel throughput (and minimizing data transmission time) is addressed. The problem is formulated as a multicommodity flow problem. We present both the optimal and suboptimal solutions to the problem using novel approaches.

The reliability of a distributed computing system depends on the reliability of its communication links and nodes and on the distribution of its resources, such as programs and data files. Many algorithms have been proposed for computing the reliability of distributed computing systems, but they have been applied mostly to distributed computing systems with perfect nodes. However, in real problems, nodes as well as links may fail. This paper proposes two new algorithms for computing the reliability of a distributed computing system with imperfect nodes. Algorithm I is based on a symbolic approach that includes two passes of computation. Algorithm II employs a general factoring technique on both nodes and edges. Comparisons with existing methods show the usefulness of the proposed algorithms for computing the reliability of large distributed computing systems.

We show that computing distributed program reliability on the star distributed computing system is NP-hard. We develop a polynomially solvable case to compute distributed program reliability when some additional file distribution is restricted on the star topology. We also propose a polynomial time algorithm for computing distributed program reliability with an approximate solution when the star topology is not satisfied with the additional file distribution.

The use of the Internet for various business applications and resource sharing has grown tremendously over the last few years. In some applications, an important document may be required to be divided into pieces and be allocated in different locations over the Internet for security access concerns. For example, an important map that can be used to access a military base, an important key that can be used to give a military order or command. To access such an important document, one must reconstruct the divided pieces from different locations. In this paper, a probability model for reconstructing the secret sharing under the Internet is proposed. Also, how to assign the divided shares into different locations is studied. Particularly, algorithms to perform share assignment and to reconstruct the divided pieces into the original secret are proposed.

Distributed Multimedia Database Systems (DMDB) have gained in popularity for today's database system design due to their fault-tolerance, resource-sharing capacity, and reliable performance. Reliability performance is an important issue in DMDB design. The reliability of a DMDB depends on the reliability of its communication links and nodes as well as the distribution of its resources, such as various media. The distribution of media is an important factor that affects the multimedia query and access reliability (MQAR). The reliability-oriented media assignment problem is to find a media distribution such that the MQAR is maximal. In this paper, we attempt to develop a reliability model and algorithms to achieve reliability-oriented media allocation.

In this paper, we attempt to develop reliability models for the reliability analyses in distributed multimedia system. We propose two polynomial-time algorithms to compute the multimedia task reliability (MTR) and time-constraint multimedia task reliability (TCMTR) for distributed multimedia system based on token ring networks. Two main algorithms, multimedia task reliability for ring (MTRR) and multimedia task reliability for path (MTRP), are used to compute the MTR. For time constraint media access, we extend our proposed algorithms to compute TCMTR.

We develop a heuristic algorithm for the reliability-oriented file assignment problem (HROFA), which uses a careful reduction method to reduce the problem space. Based on some numerical results, the HROFA algorithm obtains the exact solution in most cases and the computation time is improved significantly. When it fails to give an exact solution, the deviation from the exact solution is very small.

Presents an algorithm for computing the reliability of distributed computing systems (DCS). The algorithm, called the Fast Reliability Evaluation Algorithm, is based on the factoring theorem employing several reliability preserving reduction techniques. The effect of file distributions, program distributions, and various topologies on reliability of the DCS is studied in detail using the proposed algorithm. Compared with existing algorithms on various network topologies, file distributions, and program distributions, the proposed algorithm is much more economical in both time and space. To compute the distributed program reliability, the ARPA network is studied to illustrate the feasibility of the proposed algorithm.>

The reliability of a distributed computing system is the probability that a distributed program which runs on multiple processing elements and needs to communicate with other processing elements for remote data files will be executed successfully. This reliability varies according to (1) the topology of the distributed computing system, (2) the reliability of the communication links, (3) the data files and program distribution among processing elements, and (4) the data files required to execute a program. Thus, the problem of analyzing the reliability of a distributed computing system is more complicated than the K-terminal reliability problem, and many of the reliability-preserving reductions for speeding up the computation of the K-terminal reliability cannot be applied to this problem. In this paper, we shall propose several reduction methods for computing the reliability of distributed computing systems. These reduction methods can dramatically reduce the size of a distributed computing systems, and therefore speed up the reliability computation.

In object-oriented systems, heavy message sending has slowed down the execution efficiency. Most of the current solutions are based on message tables according to a class-hierarchy to develop more efficient method searching algorithms. An approach with little space overhead and constant dispatch time is proposed. The general strategy is called the two-way coloring technique. The algorithm can be applied in both typed and untyped object-oriented languages. For typed languages, the space overhead is not greater than the conventional approaches, but it can dispatch methods in the same situations as untyped languages. For untyped languages, the constraint for dispatch is not decreased and the space overhead is not much higher, but it can dispatch methods in constant time. Based on the comparison with conventional approaches, the proposed approach demonstrates its advantages on space overhead, dispatching speed, and applicability. Several case studies are presented as a comparison with existing run time dispatch mechanisms.>

The reliability of a distributed processing system (DPS) can be expressed by the analysis of distributed program reliability (DPR) and distributed system reliability (DSR). One of the good approaches to formulate these reliability performance indexes is to generate all disjoint file spanning trees (FSTs) in the DPS graph such that the DPR and DSR can be expressed by the probability that at least one of these FSTs is working. In the paper, a unified algorithm to efficiently generate disjoint FSTs by cutting different links is presented, and the DPR and DSR are computed based on a simple and consistent union operation on the probability space of the FSTs. The DPS reliability related problems are also discussed. For speeding up the reliability evaluation, nodes merged, series, and parallel reduction concepts are incorporated in the algorithm. Based on the comparison of number of subgraphs (or FSTs) generated by the proposed algorithm and by existing evaluation algorithms, it is concluded that the proposed algorithm is much more economic in terms of time and space than the existing algorithms.>