It is well known that TCP does not fully utilize the available bandwidth in fast long-distance networks. To solve this scalability problem, several high speed transport protocols have been proposed. They include HighSpeed TCP (HS-TCP), Scalable TCP (S-TCP), Binary increase control TCP (BIC-TCP), and H-TCP. These protocols increase (decrease) their window size more aggressively (slowly) compared to standard TCP (STD-TCP). This paper aims at evaluating and comparing these high speed transport protocols through computer simulations. We select six metrics that are important for high speed protocols; scalability, buffer requirement, TCP friendliness, TCP compatibility, RTT fairness, and responsiveness. Simulation scenarios are carefully designed to investigate the performance of these protocols in terms of the metrics. Results clarify that each high speed protocol successfully solves the problem of STD-TCP. In terms of the buffer requirement, S-TCP and BIC-TCP have better performance. For TCP friendliness and compatibility, HS-TCP and H-TCP offer better performance. For RTT fairness, BIC-TCP and H-TCP are superior. For responsiveness, HS-TCP and H-TCP are preferred. However, H-TCP achieves a high degree of fairness at the expense of the link utilization. Thus, we understand that all the proposed high speed transport protocols have their own shortcomings. Thus, much more research is needed on high speed transport protocols.

Web browsing task is based on depth-first searching scheme, so that searching relevant information from Web may be very tedious. In this paper, we propose personal browsing assistant system based on user intentions modeling. Before explicitly requested by a user, this system can analyze the prefetched resources from the hyperlinked Webpages and compare them with the estimated user intention, so that it can help him to make a better decision like which Webpage should be requested next. More important problem is the semantic heterogeneity between Web spaces. It makes the understandability of locally annotated resources more difficult. We apply semantic annotation, which is a transcoding procedure with the global ontology. Therefore, each local metadata can be semantically enriched, and efficiently comparable. As testing bed of our experiment, we organized three different online clothes stores whose images are annotated by semantically heterogeneous metadata. We simulated virtual customers navigating these cyberspaces. According to the predefined preferences of customer models, they conducted comparison-shopping. We have shown the reasonability of supporting the Web browsing, and its performance was evaluated as measuring the total size of browsed hyperspace.

This paper describes techniques of scoring prosodic proficiency of English sentences spoken by Japanese. The multiple regression model predicts the prosodic proficiency using new prosodic measures based on the characteristics of Japanese novice learners of English. Prosodic measures are calculated by comparing prosodic parameters, such as F0, power and duration, of learner's and native speaker's speech. The new measures include the approximation error of the fitting line and the comparison result of prosodic parameters for a limited segment of the word boundary rather than the whole utterance. This paper reveals that the introduction of the new measures improved the correlation by 0.1 between the teachers' and automatic scores.

This paper describes a new fast learning algorithm for Self-Organizing Map employing a "rough comparison winner-take-all" and its digital hardware architecture. In rough comparison winner-take-all algorithm, the winner unit is roughly and strictly assigned in early and later learning stage, respectively. It realizes both of high accuracy and fast learning. The digital hardware of the self-organizing map with proposed WTA algorithm is implemented using FPGA. Experimental results show that the designed hardware is superior to other hardware with respect to calculation speed.

This paper presents a voltage-mode WTA/MAX circuit that achieves high-speed and multi-chip features. Based on the efficient averaged-value comparison approach, the time and hardware complexities are proportional to O(log N) and O(N) respectively, where N is the number of inputs. In addition, a voltage comparison element (VCE) circuit is proposed to achieve multi-chip function. In the proposed circuit, the averaged-value calculator is built using resistor array that prevents the matching problem of transistor array. The whole circuit was fabricated with the TSMC 0.35 µm signal-poly quadruple-metal CMOS process. With eight input signals, the measurement results show that the proposed circuit resolved input voltages differing by 10 mV in 30 ns, and the multi-chip capability was also verified.

DualFS is a next-generation journaling file system which has the same consistency guaranties as traditional journaling file systems but better performance. This paper introduces three new enhancements which significantly improve DualFS performance during normal operation, and presents different experimental results which compare DualFS and other traditional file systems, namely, Ext2, Ext3, XFS, JFS, and ReiserFS. The experiments carried out prove, for the first time, that a new file system design based on separation of data and metadata can significantly improve file systems' performance without requiring several storage devices.

A new approach for electronic sealed-bid auctions that preserve the privacy of losing bids is presented. It reduces the number of operations performed by the auctioneers to O(log ); previous protocols require O(N ) or O(N log ) where the number of bidders is N and that of available bidding prices is . Namely, the number of auctioneers' operations in our auction protocol is independent of the number of bidders. This feature offers strong advantages in massive auctions. We also propose a new scheme that checks the equality of two values without disclosing them. The scheme enhances our basic auction protocol, in terms of security and communication costs.

The auction is a popular way of trading. Despite of the popularity of the auction, only a small number of papers have addressed the protocol which realize the double auction. In this paper, we propose a new method of double auction which improves the algorithm of the existing double auction protocol. Our new method is based on the idea of number comparison which is realized by homomorphic encryption. The new method solves the problem of the privacy of losing bids found in the existing algorithm. The buyers and the sellers can embed a random number in their bidding information by the use of the homomorphic encryption. The players in an auction cannot get anyone else's bidding information. The new method is more efficient than the existing ones. Our new method satisfies the criteria for the auction protocol.

Ranking fuzzy numbers is one of very important research topics in fuzzy set theory because it is a base of decision-making in applications. However, fuzzy numbers may not be easily ordered into one sequence according to their magnitudes because they represent uncertain values. When two fuzzy numbers overlap with each other, a fuzzy number may not be considered absolutely larger than the other. That is, even when a fuzzy number may be considered larger than the other, it may also be considered smaller than the other. It means that for a given set of fuzzy numbers, several ranking sequences possibly exist. However, most of the existing ranking methods produce only one ranking sequence. They ignore other possible sequences due to the overlap between fuzzy numbers. We propose a ranking method which generates possible ranking sequences of given fuzzy numbers. Our method takes a viewpoint from users, and uses it for evaluation of fuzzy numbers. Fuzzy numbers will be ranked based on the evaluations and a fuzzy set of sequences of fuzzy numbers will be produced as a ranking results. Numeric examples and comparisons with other methods are also presented.

This paper assesses the media synchronization quality of recovery control schemes from asynchrony, which are referred to as reactive control schemes here, in terms of objective and subjective measures. We deal with four reactive control techniques: skipping, discarding, shortening and extension of output duration, and virtual-time contraction and expansion. We have carried out subjective and objective assessment of the media synchronization quality of nine schemes which consist of combinations of the four techniques. The paper makes a comparison of media synchronization quality among the schemes. It also clarifies the relations between the two kinds of quality measures.

We consider diagnosability of butterfly networks under the comparison approach proposed by Maeng and Malek. Sengupta and Dahbura discussed characterization of diagnosable systems under the comparison approach, and designed a polynomial time algorithm to identify the faulty processors. However, for a general system, it is not algorithmically easy to determine its diagnosability. This paper proposes two comparison schemes for generating syndromes on butterfly networks, and determine the diagnosability of the network.

In this paper, we study system-level diagnosis under the comparison approach proposed by Maeng and Malek. Sengupta and Dahbura designed an O(n5) time diagnosis algorithm for identifying all faulty nodes in general graphs (n is the number of nodes in a system). We consider diagnosis on a butterfly network BF(k,r) and propose O(k2 n) time diagnosis algorithms for locating all faulty nodes in BF(k,r).

This paper proposes a framework for building a customized comparison-shopping system in which the users are allowed to add their own shopping stores dynamically. In this framework, a shopping agent is implemented with a robust inductive learning method that automatically constructs wrappers for semi-structured online stores. During learning, strong biases assumed in many existing systems are weakened so that the real stores with reasonably complex document structures can be handled.

Chen et al., have proposed a new estimation method for the membership values in fuzzy sets. The proposed scheme takes input from empirical/experimental data, which reflect the expert's knowledge on the relative degree of belonging of the members, and then searches for the best fit membership values of the element. Through the estimation of the practical case (Sect. 3 in [1]) the algorithm suggests to normalize the estimated membership values if there is any among them more than one and change some condition to guarantee its positiveness. In this paper, we show how to use the same imposed condition to guarantee that the estimated membership values will be within the unit interval without normalization.

In this paper, we propose a method for detecting conserved domains from a set of amino acid sequences that belong to a protein family. This method detects the domains as follows: first, generate fixed-length subsequences from the sequences; second, construct a weighted graph that connects any two of the subsequences (vertices) having higher similarity than a pre-defined threshold; third, search for the maximum-density subgraph for each connected component of the graph; finally, explore conserved domains in the sequences by combining the results of the previous step. From the performance results obtained by applying the method to several protein families that have complex conserved domains, we found that our method was able to detect those domains even though some domains were weakly conserved.

In a phase-locked-loop (PLL) frequency synthesizer with binary phase comparison, jitter is hard to suppress. In this paper, we propose a PLL frequency synthesizer with an improved binary phase comparison which can solve the above problem. The effectiveness of the proposed method is confirmed by PSpice simulation results.

This paper presents a performance comparison between the single-stream and the multi-stream approaches to lip synchronization of live media (voice and video). The former transmits a single transport stream of interleaved voice and video, while the latter treats the two media as separate transport streams. Each approach has an option not to exert the synchronization control at the destination, which leads to four basic schemes. On an interconnected ATM-wireless LAN, we implemented the four basic schemes with RTP/RTCP on top of UDP and two variants which exercise dynamic resolution control of JPEG video. Making the performance measurement of the six schemes, we compare them to identify and evaluate advantages and disadvantages of each approach. We then show that the performance difference between the two approaches is small and that the dynamic resolution control improves the synchronization quality.

Maximal-ratio combining (MRC), which maximizes the carrier to noise ratio (CNR) of the combined signal, generally requires envelope detection and multiplication having linear characteristic over a wide dynamic range to generate a weighting factor for each branch. In this paper, we propose a simplified two-branch diversity combining scheme without linear envelope detection. The proposed scheme, called "level comparison weighted combining (LCWC),"is simplified in a manner that its weighting factor for each branch is generated from hard-decision results of comparing signal envelopes between two branches. Performance of LCWC is evaluated by computer simulation and laboratory experiment, which shows that its diversity gain is almost identical to that of MRC in a Rayleigh fading channel.

Electric fishes generate an AC electric field around themselves by the electric organ in the tail. Spatial distortion of the field by nearby objects is detected by an electroreceptor array located an over the body surface to localize the object electrically when other senses such as vision and mechanosense are useless. Each fish has its own 'frequency band' for its electric organ discharges, and jamming of the electrolocation system occurs when two fish with similar discharge frequencies encounter. To avoid janmming, the fish shift their discharge frequencies in appropriate directions. A computational algorithm for this electrical behavior and its neuronal implementation by the brain have been discovered. The design features of the system, however, are rather complex for this simple behavior and cannot be readily explained by functional optimization processes during evolution. To gain insights into the origin of the design features, two independently evolved electric fish species which perform the same behavior are compared. Complex features of the neuronal computation may be explained by the evolutionary history of neuronal elements.

Various kinds of new architectures have been proposed to enhance operating performance of the DRAM. This paper reviews these architectures including EDO, SDRAM, RDRAM, EDRAM, and CDRAM. The EDO slightly modifies the output control of the conventional DRAM architecture. Other innovative architectures try to enhance the performance by taking advantage of DRAM's internal multiple bits architecture with internal pipeline, parallel-serial conversion, or static buffers/on-chip cache. A quantitative analysis based on an assumption of wait cycles was made to compare PC system performance with some architectures. The calculation indicated the effectiveness of external or on-chip cache. Future trends cover high-speed I/O interface, unified memory architecture, and system integrated memory. The interface includes limited I/O swing such as HSTL and SSTL to realize more than 100MHz operation. Also, Ramlink and SyncLink are briefly reviewed as candidates for next generation interface. Unified memory architecture attempts to save total memory capacity by combining graphics and main memory. Advanced device technology enables system integration which combine system logic and memory. It suggests one potential direction towards system on a chip in the future.