IEICE Transactions on Information and Systems
Online ISSN : 1745-1361
Print ISSN : 0916-8532
Volume E102.D, Issue 3
Displaying 1-39 of 39 articles from this issue
Special Section on Foundations of Computer Science — Algorithm, Theory of Computation, and their Applications —
• Taisuke IZUMI
2019 Volume E102.D Issue 3 Pages 415
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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• Koji OUCHI, Ryuhei UEHARA
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 416-422
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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We investigate enumeration of distinct flat-foldable crease patterns under the following assumptions: positive integer n is given; every pattern is composed of n lines incident to the center of a sheet of paper; every angle between adjacent lines is equal to 2π/n; every line is assigned one of “mountain,” “valley,” and “flat (or consequently unfolded)”; crease patterns are considered to be equivalent if they are equal up to rotation and reflection. In this natural problem, we can use two well-known theorems for flat-foldability: the Kawasaki Theorem and the Maekawa Theorem in computational origami. Unfortunately, however, they are not enough to characterize all flat-foldable crease patterns. Therefore, so far, we have to enumerate and check flat-foldability one by one using computer. In this study, we develop the first algorithm for the above stated problem by combining these results in a nontrivial way and show its analysis of efficiency.

• Tatsuhiko HATANAKA, Takehiro ITO, Xiao ZHOU
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 423-429
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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We study the problem of transforming one (vertex) c-coloring of a graph into another one by changing only one vertex color assignment at a time, while at all times maintaining a c-coloring, where c denotes the number of colors. This decision problem is known to be PSPACE-complete even for bipartite graphs and any fixed constant c ≥ 4. In this paper, we study the problem from the viewpoint of graph classes. We first show that the problem remains PSPACE-complete for chordal graphs even if c is a fixed constant. We then demonstrate that, even when c is a part of input, the problem is solvable in polynomial time for several graph classes, such as k-trees with any integer k ≥ 1, split graphs, and trivially perfect graphs.

• Toshiki SHIBAHARA, Yuta TAKATA, Mitsuaki AKIYAMA, Takeshi YAGI, Kunio ...
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 430-443
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Many users are exposed to threats of drive-by download attacks through the Web. Attackers compromise vulnerable websites discovered by search engines and redirect clients to malicious websites created with exploit kits. Security researchers and vendors have tried to prevent the attacks by detecting malicious data, i.e., malicious URLs, web content, and redirections. However, attackers conceal parts of malicious data with evasion techniques to circumvent detection systems. In this paper, we propose a system for detecting malicious websites without collecting all malicious data. Even if we cannot observe parts of malicious data, we can always observe compromised websites. Since vulnerable websites are discovered by search engines, compromised websites have similar traits. Therefore, we built a classifier by leveraging not only malicious but also compromised websites. More precisely, we convert all websites observed at the time of access into a redirection graph and classify it by integrating similarities between its subgraphs and redirection subgraphs shared across malicious, benign, and compromised websites. As a result of evaluating our system with crawling data of 455,860 websites, we found that the system achieved a 91.7% true positive rate for malicious websites containing exploit URLs at a low false positive rate of 0.1%. Moreover, it detected 143 more evasive malicious websites than the conventional content-based system.

• Masahiro SHIBATA, Daisuke NAKAMURA, Fukuhito OOSHITA, Hirotsugu KAKUGA ...
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 444-453
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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In this paper, we consider the partial gathering problem of mobile agents in arbitrary networks. The partial gathering problem is a generalization of the (well-investigated) total gathering problem, which requires that all the agents meet at the same node. The partial gathering problem requires, for a given positive integer g, that each agent should move to a node and terminate so that at least g agents should meet at each of the nodes they terminate at. The requirement for the partial gathering problem is no stronger than that for the total gathering problem, and thus, we clarify the difference on the move complexity between them. First, we show that agents require Ω(gn+m) total moves to solve the partial gathering problem, where n is the number of nodes and m is the number of communication links. Next, we propose a deterministic algorithm to solve the partial gathering problem in O(gn+m) total moves, which is asymptotically optimal in terms of total moves. Note that, it is known that agents require Ω(kn+m) total moves to solve the total gathering problem in arbitrary networks, where k is the number of agents. Thus, our result shows that the partial gathering problem is solvable with strictly fewer total moves compared to the total gathering problem in arbitrary networks.

• Hiroto YASUMI, Fukuhito OOSHITA, Ken'ichi YAMAGUCHI, Michiko INOUE
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 454-463
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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In this paper, we consider a uniform bipartition problem in a population protocol model. The goal of the uniform bipartition problem is to divide a population into two groups of the same size. We study the problem under global fairness with various assumptions: 1) a population with or without a base station, 2) symmetric or asymmetric protocols, and 3) designated or arbitrary initial states. As a result, we completely clarify solvability of the uniform bipartition problem under global fairness and, if solvable, show the tight upper and lower bounds on the number of states.

• Kunihiro WASA, Katsuhisa YAMANAKA, Hiroki ARIMURA
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 464-469
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Given two feasible solutions A and B, a reconfiguration problem asks whether there exists a reconfiguration sequence (A0=A, A1,...,A=B) such that (i) A0,...,A are feasible solutions and (ii) we can obtain Ai from Ai-1 under the prescribed rule (the reconfiguration rule) for each i ∈ {1,...,ℓ}. In this paper, we address the reconfiguration problem for induced trees, where an induced tree is a connected and acyclic induced subgraph of an input graph. We consider the following two rules as the prescribed rules: Token Jumping: removing u from an induced tree and adding v to the tree, and Token Sliding: removing u from an induced tree and adding v adjacent to u to the tree, where u and v are vertices of an input graph. As the main results, we show that (I) the reconfiguration problemis PSPACE-complete even if the input graph is of bounded maximum degree, (II) the reconfiguration problem is W[1]-hard when parameterized by both the size of induced trees and the length of the reconfiguration sequence, and (III) there exists an FPT algorithm when the problem is parameterized by both the size of induced trees and the maximum degree of an input graph under Token Jumping and Token Sliding.

• Tomoyuki UCHIDA, Satoshi MATSUMOTO, Takayoshi SHOUDAI, Yusuke SUZUKI, ...
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 470-482
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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A formal graph system (FGS) is a logic programming system that directly manipulates graphs by dealing with graph patterns instead of terms of first-order predicate logic. In this paper, based on an FGS, we introduce a primitive formal ordered tree system (pFOTS) as a formal system defining labeled ordered tree languages. A pFOTS program is a finite set of graph rewriting rules. A logic program is well-known to be suitable to represent background knowledge. The query learning model is an established mathematical model of learning via queries in computational learning theory. In this learning model, we show the exact learnability of a pFOTS program consisting of one graph rewriting rule and background knowledge defined by a pFOTS program using a polynomial number of queries.

• Akinori KAWACHI, Kenichi KAWANO, François LE GALL, Suguru TAMAKI
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 483-491
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Unitary operator discrimination is a fundamental problem in quantum information theory. The basic version of this problem can be described as follows: Given a black box implementing a unitary operator US:={U1, U2} under some probability distribution over S, the goal is to decide whether U=U1 or U=U2. In this paper, we consider the query complexity of this problem. We show that there exists a quantum algorithm that solves this problem with bounded error probability using $\lceil{\sqrt{6}\theta_{\rm cover}^{-1}}\rceil$ queries to the black box in the worst case, i.e., under any probability distribution over S, where the parameter θcover, which is determined by the eigenvalues of $U_1^\dagger {U_2}$, represents the “closeness” between U1 and U2. We also show that this upper bound is essentially tight: we prove that for every θcover > 0 there exist operators U1 and U2 such that any quantum algorithm solving this problem with bounded error probability requires at least $\lceil{\frac{2}{3 \theta_{\rm cover}}}\rceil$ queries under uniform distribution over S.

• Akihiro MATSUURA, Yoshiaki SHOJI
Article type: PAPER
2019 Volume E102.D Issue 3 Pages 492-498
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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In this paper, we show the explicit formula of the recurrence relation for the Tower of Hanoi on the star graph with four vertices, where the perfect tower of disks on a leaf vertex is transferred to the central vertex. This gives the solution to the problem posed at the 17th International Conference on Fibonacci Numbers and Their Applications[11]. Then, the recurrence relation are generalized to include the ones for the original 4-peg Tower of Hanoi and the Star Tower of Hanoi of transferring the tower from a leaf to another.

• Katsuhisa YAMANAKA, Shogo KAWARAGI, Takashi HIRAYAMA
Article type: LETTER
2019 Volume E102.D Issue 3 Pages 499-501
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Let G=(V,E) be an unweighted simple graph. A distance-d independent set is a subset IV such that dist(u, v) ≥ d for any two vertices u, v in I, where dist(u, v) is the distance between u and v. Then, Maximum Distance-d Independent Set problem requires to compute the size of a distance-d independent set with the maximum number of vertices. Even for a fixed integer d ≥ 3, this problem is NP-hard. In this paper, we design an exact exponential algorithm that calculates the size of a maximum distance-3 independent set in O(1.4143n) time.

• Joong Chae NA, Inbok LEE
Article type: LETTER
2019 Volume E102.D Issue 3 Pages 502-504
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Order preserving matching refers to the problem of reporting substrings in the text which are order-isomorphic to the pattern. In this paper, we show a simple heuristic which runs in linear time on average, based on finding the largest elements in each substring and checking their locations against that of the pattern. It is easy to implement and experimental results showed that the running time grows linearly.

Regular Section
• Zhengqiang WANG, Wenrui XIAO, Xiaoyu WAN, Zifu FAN
Article type: PAPER
Subject area: Fundamentals of Information Systems
2019 Volume E102.D Issue 3 Pages 505-511
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Price-based power control problem is investigated in the spectrum sharing cognitive radio networks (CRNs) by Stackelberg game. Using backward induction, the revenue function of the primary user (PU) is expressed as a non-convex function of the transmit power of the secondary users (SUs). To solve the non-convex problem of the PU, a branch and bound based price-based power control algorithm is proposed. The proposed algorithm can be used to provide performance benchmarks for any other low complexity sub-optimal price-based power control algorithms based on Stackelberg game in CRNs.

• David ALEDO, Benjamin CARRION SCHAFER, Félix MORENO
Article type: PAPER
Subject area: Computer System
2019 Volume E102.D Issue 3 Pages 512-521
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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This paper describes the advantages and disadvantages observed when describing complex parameterizable Artificial Neural Networks (ANNs) at the behavioral level using SystemC and at the Register Transfer Level (RTL) using VHDL. ANNs are complex to parameterize because they have a configurable number of layers, and each one of them has a unique configuration. This kind of structure makes ANNs, a priori, challenging to parameterize using Hardware Description Languages (HDL). Thus, it seems intuitively that ANNs would benefit from the raise in level of abstraction from RTL to behavioral level. This paper presents the results of implementing an ANN using both levels of abstractions. Results surprisingly show that VHDL leads to better results and allows a much higher degree of parameterization than SystemC. The implementation of these parameterizable ANNs are made open source and are freely available online. Finally, at the end of the paper we make some recommendation for future HLS tools to improve their parameterization capabilities.

• Xiaoqiong ZHAO, Shanping LI, Huan YU, Ye WANG, Weiwei QIU
Article type: PAPER
Subject area: Software Engineering
2019 Volume E102.D Issue 3 Pages 522-536
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Background: The applying of third-party libraries is an integral part of many applications. But the libraries choosing is time-consuming even for experienced developers. The automated recommendation system for libraries recommendation is widely researched to help developers to choose libraries. Aim: from software engineering aspect, our research aims to give developers a reliable recommended list of third-party libraries at the early phase of software development lifecycle to help them build their development environment faster; and from technical aspect, our research aims to build a generalizable recommendation system framework which combines collaborative filtering and topic modeling techniques, in order to improve the performance of libraries recommendation significantly. Our works on this research: 1) we design a hybrid methodology to combine collaborative filtering and LDA text mining technology; 2) we build a recommendation system framework successfully based on the above hybrid methodology; 3) we make a well-designed experiment to validate the methodology and framework which use the data of 1,013 mobile application projects; 4) we do the evaluation for the result of the experiment. Conclusions: 1) hybrid methodology with collaborative filtering and LDA can improve the performance of libraries recommendation significantly; 2) based on the hybrid methodology, the framework works very well on the libraries recommendation for helping developers' libraries choosing. Further research is necessary to improve the performance of the libraries recommendation including: 1) use more accurate NLP technologies improve the correlation analysis; 2) try other similarity calculation methodology for collaborative filtering to rise the accuracy; 3) on this research, we just bring the time-series approach to the framework and make an experiment as comparative trial, the result shows that the performance improves continuously, so in further research we plan to use time-series data-mining as the basic methodology to update the framework.

• Lina GONG, Shujuan JIANG, Qiao YU, Li JIANG
Article type: PAPER
Subject area: Software Engineering
2019 Volume E102.D Issue 3 Pages 537-549
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Heterogeneous defect prediction (HDP) is to detect the largest number of defective software modules in one project by using historical data collected from other projects with different metrics. However, these data can not be directly used because of different metrics set among projects. Meanwhile, software data have more non-defective instances than defective instances which may cause a significant bias towards defective instances. To completely solve these two restrictions, we propose unsupervised deep domain adaptation approach to build a HDP model. Specifically, we firstly map the data of source and target projects into a unified metric representation (UMR). Then, we design a simple neural network (SNN) model to deal with the heterogeneous and class-imbalanced problems in software defect prediction (SDP). In particular, our model introduces the Maximum Mean Discrepancy (MMD) as the distance between the source and target data to reduce the distribution mismatch, and use the cross-entropy loss function as the classification loss. Extensive experiments on 18 public projects from four datasets indicate that the proposed approach can build an effective prediction model for heterogeneous defect prediction (HDP) and outperforms the related competing approaches.

• Yutaro HAYAKAWA, Kenichi YASUKATA, Jin NAKAZAWA, Michio HONDA
Article type: PAPER
Subject area: Information Network
2019 Volume E102.D Issue 3 Pages 550-558
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Increasing hardware resources, such as multi-core and multi-socket CPUs, memory capacity and high-speed NICs, impose significant challenges on Network Function Virtualization (NFV) backends. They increase the potential numbers of per-server NFs or tenants, which requires a packet switching architecture that is not only scalable to large number of virtual ports, but also robust to attacks on the data plane. This is a real problem; a recent study has reported that Open vSwitch, a widely used software switch, had a buffer-overflow bug in its data plane that results the entire SDN domain to be hijacked by worms propagated in the network. In order to address this problem, we propose REdge. It scales to thousands of virtual ports or NFs (as opposed to hundreds in the current state-of-the art), and protect modular, flexible packet switching logic against various bugs, such as buffer overflow and other unexpected operations using static program checking. When 2048 NFs are active and packets are distributed to them based on the MAC or IP addresses, REdge achieves 3.16 Mpps or higher packet forwarding rates for 60 byte packets and achieves the wire rate for 1500 byte packets in the 25 Gbps link.

• Hisao OGATA, Tomoyoshi ISHIKAWA, Norichika MIYAMOTO, Tsutomu MATSUMOTO
Article type: PAPER
Subject area: Dependable Computing
2019 Volume E102.D Issue 3 Pages 559-567
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Recently, criminals frequently utilize logical attacks to install malware in the PC of Automated Teller Machines (ATMs) for the sake of unauthorized cash withdrawal from ATMs. Malware in the PC sends unauthorized cash dispensing commands to the dispenser to withdraw cash without generating a transaction. Existing security measures primarily try to protect information property in the PC so as not to be compromised by malware. Such security measures are not so effective or efficient because the PC contains too many protected items to tightly control them in present ATM operational environments. This paper proposes a new ATM security measure based on secure peripheral devices; the secure dispenser in an ATM verifies the authenticity of a received dispensing command with the withdrawal transaction evidence, which is securely transferred from the secure card reader of an ATM. The card reader can capture the transaction evidence since all transaction data flows through the card reader in a smart card transaction. Even though the PC is compromised, unauthorized dispensing commands are not accepted by the secure dispenser. As a result, the new security measure does not impose heavy burden of tighter security managements for the PCs on financial institutes while achieving stringent security for the logical attacks to ATMs.

• Xiaotao CHENG, Lixin JI, Ruiyang HUANG, Ruifei CUI
Article type: PAPER
Subject area: Artificial Intelligence, Data Mining
2019 Volume E102.D Issue 3 Pages 568-578
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Network embedding has attracted an increasing amount of attention in recent years due to its wide-ranging applications in graph mining tasks such as vertex classification, community detection, and network visualization. Network embedding is an important method to learn low-dimensional representations of vertices in networks, aiming to capture and preserve the network structure. Almost all the existing network embedding methods adopt the so-called Skip-gram model in Word2vec. However, as a bag-of-words model, the skip-gram model mainly utilized the local structure information. The lack of information metrics for vertices in global network leads to the mix of vertices with different labels in the new embedding space. To solve this problem, in this paper we propose a Network Representation Learning method with Deep Metric Learning, namely DML-NRL. By setting the initialized anchor vertices and adding the similarity measure in the training progress, the distance information between different labels of vertices in the network is integrated into the vertex representation, which improves the accuracy of network embedding algorithm effectively. We compare our method with baselines by applying them to the tasks of multi-label classification and data visualization of vertices. The experimental results show that our method outperforms the baselines in all three datasets, and the method has proved to be effective and robust.

• Yukihiro TAGAMI
Article type: PAPER
Subject area: Artificial Intelligence, Data Mining
2019 Volume E102.D Issue 3 Pages 579-587
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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As the data size of Web-related multi-label classification problems continues to increase, the label space has also grown extremely large. For example, the number of labels appearing in Web page tagging and E-commerce recommendation tasks reaches hundreds of thousands or even millions. In this paper, we propose a graph partitioning tree (GPT), which is a novel approach for extreme multi-label learning. At an internal node of the tree, the GPT learns a linear separator to partition a feature space, considering approximate k-nearest neighbor graph of the label vectors. We also developed a simple sequential optimization procedure for learning the linear binary classifiers. Extensive experiments on large-scale real-world data sets showed that our method achieves better prediction accuracy than state-of-the-art tree-based methods, while maintaining fast prediction.

• Cong LIU, Qingtian ZENG, Hua DUAN, Shangce GAO, Chanhong ZHOU
Article type: PAPER
Subject area: Office Information Systems, e-Business Modeling
2019 Volume E102.D Issue 3 Pages 588-597
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Business process similarity measure is required by many applications, such as business process query, improvement, redesign, and etc. Many process behavior similarity measures have been proposed in the past two decades. However, to the best of our knowledge, most existing work only focuses on the direct causality transition relations and totally neglect the concurrent and transitive transition relations that are proved to be equally important when measuring process behavior similarity. In this paper, we take the weakness of existing process behavior similarity measures as a starting point, and propose a comprehensive approach to measure the business process behavior similarity based on the so-called Extended Transition Relation set, ETR-set for short. Essentially, the ETR-set is an ex-tended transition relation set containing direct causal transition relations, minimum concurrent transition relations and transitive causal transition relations. Based on the ETR-set, a novel process behavior similarity measure is defined. By constructing a concurrent reachability graph, our approach finds an effective technique to obtain the ETR-set. Finally, we evaluate our proposed approach in terms of its property analysis as well as conducting a group of control experiments.

• Michael HENTSCHEL, Marc DELCROIX, Atsunori OGAWA, Tomoharu IWATA, Tomo ...
Article type: PAPER
Subject area: Speech and Hearing
2019 Volume E102.D Issue 3 Pages 598-608
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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• Ying CAO, Lijuan SUN, Chong HAN, Jian GUO
Article type: PAPER
Subject area: Image Processing and Video Processing
2019 Volume E102.D Issue 3 Pages 609-619
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Due to the inevitable data missing problem during visual data acquisition, the recovery of color images and videos from limited useful information has become an important topic, for which tensor completion has been proved to be a promising solution in previous studies. In this paper, we propose a novel completion scheme, which can effectively recover missing entries in color images and videos represented by tensors. We first employ a modified tensor train (TT) decomposition as tensor approximation scheme in the concept of TT rank to generate better-constructed and more balanced tensors which preserve only relatively significant informative data in tensors of visual data. Afterwards, we further introduce a TT rank-based weight scheme which can define the value of weights adaptively in tensor completion problem. Finally, we combine the two schemes with Simple Low Rank Tensor Completion via Tensor Train (SiLRTC-TT) to construct our completion algorithm, Low Rank Approximated Tensor Completion via Adaptive Tensor Train (LRATC-ATT). Experimental results validate that the proposed approach outperforms typical tensor completion algorithms in recovering tensors of visual data even with high missing ratios.

• Xiaoxia LIU, Degen HUANG, Zhangzhi YIN, Fuji REN
Article type: PAPER
Subject area: Natural Language Processing
2019 Volume E102.D Issue 3 Pages 620-627
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Collocation is a ubiquitous phenomenon in languages and accurate collocation recognition and extraction is of great significance to many natural language processing tasks. Collocations can be differentiated from simple bigram collocations to collocation frames (referring to distant multi-gram collocations). So far little focus is put on collocation frames. Oriented to translation and parsing, this study aims to recognize and extract the longest possible collocation frames from given sentences. We first extract bigram collocations with distributional semantics based method by introducing collocation patterns and integrating some state-of-the-art association measures. Based on bigram collocations extracted by the proposed method, we get the longest collocation frames according to recursive nature and linguistic rules of collocations. Compared with the baseline systems, the proposed method performs significantly better in bigram collocation extraction both in precision and recall. And in extracting collocation frames, the proposed method performs even better with the precision similar to its bigram collocation extraction results.

• Xilu WANG, Yongjun SUN, Huaxi GU
Article type: LETTER
Subject area: Fundamentals of Information Systems
2019 Volume E102.D Issue 3 Pages 628-631
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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The mapping optimization problem in Network-on-Chip (NoC) is constraint and NP-hard, and the deterministic algorithms require considerable computation time to find an exact optimal mapping solution. Therefore, the metaheuristic algorithms (MAs) have attracted great interests of researchers. However, most MAs are designed for continuous problems and suffer from premature convergence. In this letter, a binary metaheuristic mapping algorithm (BMM) with a better exploration-exploitation balance is proposed to solve the mapping problem. The binary encoding is used to extend the MAs to the constraint problem and an adaptive strategy is introduced to combine Sine Cosine Algorithm (SCA) and Particle Swarm Algorithm (PSO). SCA is modified to explore the search space effectively, while the powerful exploitation ability of PSO is employed for the global optimum. A set of well-known applications and large-scale synthetic cores-graphs are used to test the performance of BMM. The results demonstrate that the proposed algorithm can improve the energy consumption more significantly than some other heuristic algorithms.

• Hakbeom JANG, Jonghyun BAE, Tae Jun HAM, Jae W. LEE
Article type: LETTER
Subject area: Computer System
2019 Volume E102.D Issue 3 Pages 632-636
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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This paper introduces e-spill, an eager spill mechanism, which dynamically finds the optimal spill-threshold by monitoring the GC time at runtime and thereby prevent expensive GC overhead. Our e-spill adopts a slow-start model to gradually increase the spill-threshold until it reaches the optimal point without substantial GCs. We prototype e-spill as an extension to Spark and evaluate it using six workloads on three different parallel platforms. Our evaluations show that e-spill improves performance by up to 3.80× and saves the cost of cluster operation on Amazon EC2 cloud by up to 51% over the baseline system following Spark Tuning Guidelines.

Article type: LETTER
Subject area: Software Engineering
2019 Volume E102.D Issue 3 Pages 637-639
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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This paper presents a concept of a domain-specific framework for software analytics by enabling querying, modeling, and integration of heterogeneous software repositories. The framework adheres to a multi-layered abstraction mechanism that consists of domain-specific operators. We showcased the potential of this approach by employing a case study.

• Sangwook BAK, Young-Joo SUH
Article type: LETTER
Subject area: Information Network
2019 Volume E102.D Issue 3 Pages 640-644
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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This paper proposes an enhanced BLE scanner with user-level channel awareness and simultaneous channel scanning to increase theoretical scanning capability by up to three times. With better scanning capability, channel analysis quality also has been improved by considering channel-specific signal characteristics, without the need of beacon-side changes.

• Muhammad HATABA, Ahmed EL-MAHDY, Kazunori UEDA
Article type: LETTER
Subject area: Dependable Computing
2019 Volume E102.D Issue 3 Pages 645-649
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Nowadays the computing technology is going through a major paradigm shift. Local processing platforms are being replaced by physically out of reach yet more powerful and scalable environments such as the cloud computing platforms. Previously, we introduced the OJIT system as a novel approach for obfuscating remotely executed programs, making them difficult for adversaries to reverse-engineer. The system exploited the JIT compilation technology to randomly and dynamically transform the code, making it constantly changing, thereby complicating the execution state. This work aims to propose the new design iOJIT, as an enhanced approach that patches the old systems shortcomings, and potentially provides more effective obfuscation. Here, we present an analytic study of the obfuscation techniques on the generated code and the cost of applying such transformations in terms of execution time and performance overhead. Based upon this profiling study, we implemented a new algorithm to choose which obfuscation techniques would be better chosen for “efficient” obfuscation according to our metrics, i.e., less prone to security attacks. Another goal was to study the system performance with different applications. Therefore, we applied our system on a cloud platform running different standard benchmarks from SPEC suite.

• Siyu CHEN, Ning WANG, Mengmeng ZHANG
Article type: LETTER
Subject area: Artificial Intelligence, Data Mining
2019 Volume E102.D Issue 3 Pages 650-654
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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We propose to discover approximate primary functional dependency (aPFD) for web tables, which focus on the determination relationship between primary attributes and non-primary attributes and are more helpful for entity column detection and topic discovery on web tables. Based on association rules and information theory, we propose metrics Conf and InfoGain to evaluate PFDs. By quantifying PFDs' strength and designing pruning strategies to eliminate false positives, our method could select minimal non-trivial approximate PFD effectively and are scalable to large tables. The comprehensive experimental results on real web datasets show that our method significantly outperforms previous work in both effectiveness and efficiency.

• Yilu MA, Yuehua LI
Article type: LETTER
Subject area: Pattern Recognition
2019 Volume E102.D Issue 3 Pages 655-658
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Target recognition in Millimeter-wave Interferometric Synthetic Aperture Radiometer (MMW InSAR) imaging is always a crucial task. However, the recognition performance of conventional algorithms degrades when facing unpredictable noise interference in practical scenarios and information-loss caused by inverse imaging processing of InSAR. These difficulties make it very necessary to develop general-purpose denoising techniques and robust feature extractors for InSAR target recognition. In this paper, we propose a denoising convolutional neural network (D-CNN) and demonstrate its advantage on MMW InSAR automatic target recognition problem. Instead of directly feeding the MMW InSAR image to the CNN, the proposed algorithm utilizes the visibility function samples as the input of the fully connected denoising layer and recasts the target recognition as a data-driven supervised learning task, which learns the robust feature representations from the space-frequency domain. Comparing with traditional methods which act on the MMW InSAR output images, the D-CNN will not be affected by information-loss accused by inverse imaging process. Furthermore, experimental results on the simulated MMW InSAR images dataset illustrate that the D-CNN has superior immunity to noise, and achieves an outstanding performance on the recognition task.

• Fei WU, Xiwei DONG, Lu HAN, Xiao-Yuan JING, Yi-mu JI
Article type: LETTER
Subject area: Pattern Recognition
2019 Volume E102.D Issue 3 Pages 659-662
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Recently, multi-view dictionary learning technique has attracted lots of research interest. Although several multi-view dictionary learning methods have been addressed, they can be further improved. Most of existing multi-view dictionary learning methods adopt the l0 or l1-norm sparsity constraint on the representation coefficients, which makes the training and testing phases time-consuming. In this paper, we propose a novel multi-view dictionary learning approach named multi-view synthesis and analysis dictionaries learning (MSADL), which jointly learns multiple discriminant dictionary pairs with each corresponding to one view and containing a structured synthesis dictionary and a structured analysis dictionary. MSADL utilizes synthesis dictionaries to achieve class-specific reconstruction and uses analysis dictionaries to generate discriminative code coefficients by linear projection. Furthermore, we design an uncorrelation term for multi-view dictionary learning, such that the redundancy among synthesis dictionaries learned from different views can be reduced. Two widely used datasets are employed as test data. Experimental results demonstrate the efficiency and effectiveness of the proposed approach.

• Masanori MORISE
Article type: LETTER
Subject area: Speech and Hearing
2019 Volume E102.D Issue 3 Pages 663-665
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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This paper introduces a new noise generation algorithm for vocoder-based speech waveform generation. White noise is generally used for generating an aperiodic component. Since short-term white noise includes a zero-frequency component (ZFC) and inaudible components below 20 Hz, they are reduced in advance when synthesizing. We propose a new noise generation algorithm based on that for velvet noise to overcome the problem. The objective evaluation demonstrated that the proposed algorithm can reduce the unwanted components.

• Zhi LIU, Cai XU, Mengmeng ZHANG, Wen YUE
Article type: LETTER
Subject area: Image Processing and Video Processing
2019 Volume E102.D Issue 3 Pages 666-669
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Virtual Reality (VR) 360 degree video has ultra-high definition. Reducing the coding complexity becomes a key consideration in coding algorithm design. In this paper, a novel candidate mode pruning process is introduced between Rough Mode Decision and Most Probable Mode based on the statistical analysis of the intra-coding parameters used in VR 360 degree video coding under Cubemap projection (CMP) format. In addition, updated coding bits thresholds for VR 360 degree video are designed in the proposed algorithm. The experimental results show that the proposed algorithm brings 38.73% and 23.70% saving in average coding time at the cost of only 1.4% and 2.1% Bjontegaard delta rate increase in All-Intra mode and Randomaccess mode, respectively.

• Zhenglong YANG, Guozhong WANG, GuoWei TENG
Article type: LETTER
Subject area: Image Processing and Video Processing
2019 Volume E102.D Issue 3 Pages 670-674
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Although HEVC rate control can achieve high coding efficiency, it still does not fully utilize the special characteristics of surveillance videos, which typically have a moving foreground and relatively static background. For surveillance videos, it is usually necessary to provide a better coding quality of the moving foreground. In this paper, a foreground-background CTU λ separate decision scheme is proposed. First, low-complexity pixel-based segmentation is presented to obtain the foreground and the background. Second, the rate distortion (RD) characteristics of the foreground and the background are explored. With the rate distortion optimization (RDO) process, the average CTU λ value of the foreground or the background should be equal to the frame λ. Then, a separate optimal CTU λ decision is proposed with a separate λ clipping method. Finally, a separate updating process is used to obtain reasonable parameters for the foreground and the background. The experimental results show that the quality of the foreground is improved by 0.30 dB in the random access configuration and 0.45 dB in the low delay configuration without degradation of either the rate control accuracy or whole frame quality.

• Chunxiao FAN, Yang LI, Lei TIAN, Yong LI
Article type: LETTER
Subject area: Image Recognition, Computer Vision
2019 Volume E102.D Issue 3 Pages 675-679
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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This letter proposes a representation learning framework of convolutional neural networks (Convnets) that aims to rectify and improve the feature representations learned by existing transformation-invariant methods. The existing methods usually encode feature representations invariant to a wide range of spatial transformations by augmenting input images or transforming intermediate layers. Unfortunately, simply transforming the intermediate feature maps may lead to unpredictable representations that are ineffective in describing the transformed features of the inputs. The reason is that the operations of convolution and geometric transformation are not exchangeable in most cases and so exchanging the two operations will yield the transformation error. The error may potentially harm the performance of the classification networks. Motivated by the fractal statistics of natural images, this letter proposes a rectifying transformation operator to minimize the error. The proposed method is differentiable and can be inserted into the convolutional architecture without making any modification to the optimization algorithm. We show that the rectified feature representations result in better classification performance on two benchmarks.

• Suofei ZHANG, Bin KANG, Lin ZHOU
Article type: LETTER
Subject area: Image Recognition, Computer Vision
2019 Volume E102.D Issue 3 Pages 680-683
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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Instance features based deep learning methods prompt the performances of high speed object tracking systems by directly comparing target with its template during training and tracking. However, from the perspective of human vision system, prior knowledge of target also plays key role during the process of tracking. To integrate both semantic knowledge and instance features, we propose a convolutional network based object tracking framework to simultaneously output bounding boxes based on different prior knowledge as well as confidences of corresponding Assumptions. Experimental results show that our proposed approach retains both higher accuracy and efficiency than other leading methods on tracking tasks covering most daily objects.

• Tiansa ZHANG, Chunlei HUO, Zhiqiang ZHOU, Bo WANG
Article type: LETTER
Subject area: Image Recognition, Computer Vision
2019 Volume E102.D Issue 3 Pages 684-687
Published: March 01, 2019
Released on J-STAGE: March 01, 2019
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By taking advantages of deep learning and reinforcement learning, ADNet (Action Decision Network) outperforms other approaches. However, its speed and performance are still limited by factors such as unreliable confidence score estimation and redundant historical actions. To address the above limitations, a faster and more accurate approach named Faster-ADNet is proposed in this paper. By optimizing the tracking process via a status re-identification network, the proposed approach is more efficient and 6 times faster than ADNet. At the same time, the accuracy and stability are enhanced by historical actions removal. Experiments demonstrate the advantages of Faster-ADNet.