Accurate interpolation of seismic data is crucial for improving the quality of imaging and interpretation. In recent years, deep learning models such as U-Net and generative adversarial networks (GANs) have been widely applied to seismic data interpolation. However, they often underperform when the training and test missing patterns do not match. To alleviate this issue, here we propose a novel framework that is built upon the multimodal adaptable diffusion models. In the training phase, following the common wisdom, we use the denoising diffusion probabilistic model with a cosine noise schedule. This cosine global noise configuration improves the use of seismic data by reducing the involvement of excessive noise stages. In the inference phase, we introduce the denoising diffusion implicit model (DDIM) to reduce the number of sampling steps. Different from the conventional unconditional generation, we incorporate the known trace information into each reverse sampling step for achieving conditional interpolation. To enhance the coherence and continuity between the revealed traces and the missing traces, we further propose two strategies, including successive coherence correction and resampling. Coherence correction penalizes the mismatches in the revealed traces, while resampling conducts cyclic interpolation between adjacent reverse steps. Extensive experiments on synthetic and field seismic data validate our model’s superiority and demonstrate its generalization capability to various missing patterns and different noise levels with just one training session. In addition, uncertainty quantification and ablation studies are also investigated.

Seismic data are generally sampled irregularly and sparsely along spatial coordinates because economic costs and obstacles hinder the regular arrangement of geophones in the field. Thus, the sampled seismic data often contain missing traces which result in difficulties for later processing steps. To alleviate this issue, versatile interpolation methods have been developed to interpolate the missing traces. However, the existing models for recovering seismic data with consecutively missing traces in a large amplitude range tend to produce artifacts and blurred signal details. We propose in this paper a hybrid loss guided coarse-to-fine model which consists of a coarse network and a refinement network to allow different regions of seismic data to be recovered in different stages. The coarse network is designed to reconstruct the strong signals and the refinement network is implemented subsequently to recover the weak signals. In addition, the refinement network focuses its attention on the areas which are not well recovered by the coarse network via a weight-masked mechanism. By resorting to the hybrid loss function L1+SSIM+Relativistic Average Least-Square Generative Adversarial Network (RaLSGAN), our model enables more accurate and realistic signal details to be reconstructed. Experiments with synthetic and field data demonstrate that our model is superior to the existing mainstream approaches and the role of the key components is also investigated through ablation studies.

Recent studies have demonstrated that semi-supervised learning (SSL) approaches that use both labeled and unlabeled data are more effective and robust than those that use only labeled data. However, it is also well known that using unlabeled data is not always helpful in SSL algorithms. Thus, in order to select a small amount of helpful unlabeled samples, various selection criteria have been proposed in the literature. One criterion is based on the prediction by an ensemble classifier and the similarity between pairwise training samples. However, because the criterion is only concerned with the distance information among the samples, sometimes it does not work appropriately, particularly when the unlabeled samples are near the boundary. In order to address this concern, a method of training semi-supervised support vector machines (S3VMs) using selection criterion is investigated; this method is a modified version of that used in SemiBoost. In addition to the quantities of the original criterion, using the estimated conditional class probability, the confidence values of the unlabeled data are computed first. Then, some unlabeled samples that have higher confidences are selected and, together with the labeled data, used for retraining the ensemble classifier. The experimental results, obtained using artificial and real-life benchmark datasets, demonstrate that the proposed mechanism can compensate for the shortcomings of the traditional S3VMs and, compared with previous approaches, can achieve further improved results in terms of classification accuracy.

SUMMARY Because of the computationally expensive cost of mutation testing, automated system support is indispensable for conducting mutation testing. Mutation systems can be classified into interpretive and noninterpretive, but recent systems are noninterpretive. Weak mutation is a well‐known cost reduction method of mutation testing, but it is not directly applicable to noninterpretive mutation systems. To address the problem and take advantage of the efficiency of weak mutation, this paper presents a combined weak and strong mutation for noninterpretive Java mutation systems. The new term ‘serialmutant’ is defined as a specialized program to conduct weak mutation against all mutants in an execution and report only weakly killed mutants as strong mutation candidates. Then strong mutation is conducted only for those reported mutants. The paper also describes an implementation based on a previous Java mutation tool, MuJava. Method‐level mutation operators for Java are also redesigned. Experimental results show that the proposed approach efficiently improves the mutation cost in a noninterpretive mutation system. Copyright © 2012 John Wiley & Sons, Ltd.

Fisher's linear discriminant analysis (LDA) is a traditional dimensionality reduction method that has been proven to be successful for decades. Numerous variants, such as the kernel-based Fisher discriminant analysis (KFDA), have been proposed to enhance the LDA's power for nonlinear discriminants. Although effective, the KFDA is computationally expensive, since the complexity increases with the size of the data set. In this correspondence, we suggest a novel strategy to enhance the computation for an entire family of the KFDAs. Rather than invoke the KFDA for the entire data set, we advocate that the data be first reduced into a smaller representative subset using a prototype reduction scheme and that the dimensionality reduction be achieved by invoking a KFDA on this reduced data set. In this way, data points that are ineffective in the dimension reduction and classification can be eliminated to obtain a significantly reduced kernel matrix K without degrading the performance. Our experimental results demonstrate that the proposed mechanism dramatically reduces the computation time without sacrificing the classification accuracy for artificial and real-life data sets.

This paper reports the first known solution to the stochastic point location (SPL) problem when the environment is nonstationary. The SPL problem involves a general learning problem in which the learning mechanism (which could be a robot, a learning automaton, or, in general, an algorithm) attempts to learn a "parameter," for example, lambda*, within a closed interval. However, unlike the earlier reported results, we consider the scenario when the learning is to be done in a nonstationary setting. For each guess, the environment essentially informs the mechanism, possibly erroneously (i.e., with probability p), which way it should move to reach the unknown point. Unlike the results available in the literature, we consider the fascinating case when the point sought for is itself stochastically moving (which is modeled as follows). The environment communicates with an intermediate entity (referred to as the teacher/oracle) about the point itself, i.e., advising where it should go. The mechanism that searches for the point in turn receives responses from the teacher/oracle, which directs how it should move. Therefore, the point itself, in the overall setting, is moving, i.e., delivering possibly incorrect information about its location to the teacher/oracle. This in turn means that the "environment" is itself nonstationary, which implies that the advice of the teacher/oracle is both uncertain and changing with time-rendering the problem extremely fascinating. The heart of the strategy we propose involves discretizing the space and performing a controlled random walk on this space. Apart from deriving some analytic results about our solution, we also report the simulation results that demonstrate the power of the scheme, and state some potential applications.

In Kernel-based Nonlinear Subspace (KNS) methods, the subspace dimensions have a strong influence on the performance of the subspace classifier. In order to get a high classification accuracy, a large dimension is generally required. However, if the chosen subspace dimension is too large, it leads to a low performance due to the overlapping of the resultant subspaces and, if it is too small, it increases the classification error due to the poor resulting approximation. The most common approach is of an ad hoc nature, which selects the dimensions based on the so-called cumulative proportion computed from the kernel matrix for each class. In this paper, we propose a new method of systematically and efficiently selecting optimal or near-optimal subspace dimensions for KNS classifiers using a search strategy and a heuristic function termed the Overlapping criterion. The rationale for this function has been motivated in the body of the paper. The task of selecting optimal subspace dimensions is reduced to finding the best ones from a given problem-domain solution space using this criterion as a heuristic function. Thus, the search space can be pruned to very efficiently find the best solution. Our experimental results demonstrate that the proposed mechanism selects the dimensions efficiently without sacrificing the classification accuracy.

In Kernel-based Nonlinear Subspace (KNS) methods, the length of the projections onto the principal component directions in the feature space, is computed using a kernel matrix, K, whose dimension is equivalent to the number of sample data points. Clearly this is problematic, especially, for large data sets. In this paper, we solve this problem by subdividing the data into smaller subsets, and utilizing a Prototype Reduction Scheme (PRS) as a preprocessing module, to yield more refined representative prototypes. Thereafter, a Classifier Fusion Strategy (CFS) is invoked as a postprocessing module, to combine the individual KNS classification results to derive a consensus decision. Essentially, the PRS is used to yield computational advantage, and the CFS, in turn, is used to compensate for the decreased efficiency caused by the data set division. Our experimental results demonstrate that the proposed mechanism significantly reduces the prototype extraction time as well as the computation time without sacrificing the classification accuracy. The results especially demonstrate a significant computational advantage for large data sets within a parallel processing philosophy.

This paper gives an overview on an intelligent avatar communication system using Korean, Chinese and Japanese sign-languages to overcome the linguistic barrier between different languages. First of all, to achieve real-time communication, an intelligent communication method based on a client-server architecture and a sign-language translation method are considered. Also, to generate realistic gesture images, CG animation techniques and emotional expression methods are reviewed. Finally, to overcome the limitation based on different avatar models, a new communication message format using a FBML (facial body markup language) is investigated. Experimental results show a possibility that the methods could be used for intelligent sign-language communications between avatars of Korean, Japanese and Chinese on the Internet.

Most of the prototype reduction schemes (PRS), which have been reported in the literature, process the data in its entirety to yield a subset of prototypes that are useful in nearest-neighbor-like classification. Foremost among these are the prototypes for nearest neighbor classifiers, the vector quantization technique, and the support vector machines. These methods suffer from a major disadvantage, namely, that of the excessive computational burden encountered by processing all the data. In this paper, we suggest a recursive and computationally superior mechanism referred to as adaptive recursive partitioning (ARP)_PRS. Rather than process all the data using a PRS, we propose that the data be recursively subdivided into smaller subsets. This recursive subdivision can be arbitrary, and need not utilize any underlying clustering philosophy. The advantage of ARP_PRS is that the PRS processes subsets of data points that effectively sample the entire space to yield smaller subsets of prototypes. These prototypes are then, in turn, gathered and processed by the PRS to yield more refined prototypes. In this manner, prototypes which are in the interior of the Voronoi spaces, and thus ineffective in the classification, are eliminated at the subsequent invocations of the PRS. We are unaware of any PRS that employs such a recursive philosophy. Although we marginally forfeit accuracy in return for computational efficiency, our experimental results demonstrate that the proposed recursive mechanism yields classification comparable to the best reported prototype condensation schemes reported to-date. Indeed, this is true for both artificial data sets and for samples involving real-life data sets. The results especially demonstrate that a fair computational advantage can be obtained by using such a recursive strategy for "large" data sets, such as those involved in data mining and text categorization applications.

Various prototype reduction schemes (PRS) have been reported in the literature. Based on their operating characteristics, these schemes fall into two fairly distinct categories-those which are of a creative sort, and those which are essentially selective. The norms for evaluating these methods are typically, the reduction rate and the classification accuracy. It is generally believed that the former class of methods is superior to the latter. We report the results of executing various creative PRS and attempt to comparatively quantity their capabilities. The paper presents a brief taxonomy of the various reported PRS schemes. Our experimental results for three artificial data sets, and for samples involving real-life data sets, demonstrate that no single method is uniformly superior to the others for all kinds of applications. The conclusion of this study is that the question of determining when one method is superior to another remains open, and depends on the specific characteristics of the data that they are studying. The paper also suggests answers to various hypotheses that relate to the accuracies and reduction rates of families of PRS.

The sign language can be used as a communication means between ordinary people who have no common language. In order to get over the linguistic barrier, we had developed a 2D model-based sign-language communication system between Korea and Japan on the Internet. From the study, we discovered that there are some problems to be solved for natural animation and real-time transmission in the communication system. In this paper, we employ a 3D character model for the stereoscopic gestures of the sign-language animation, where we utilize CG-animation techniques in order to generate unartificial gestures. For real-time communication, we make use of an intelligent communication method on the client-server architecture. Using the 2D and 3D models, we implement the communication system with Visual C++ 5.0 and Open Inventor on the Windows platforms and experiment on the comparison of their availabilities. Experimental results show that both systems have some properties in their own ways and could be used for non-verbal communication between different languages beyond the linguistic barrier.