IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
Online ISSN : 1745-1337
Print ISSN : 0916-8508
Volume E102.A , Issue 2
Showing 1-25 articles out of 25 articles from the selected issue
Special Section on Mathematical Systems Science and its Applications
• Takafumi KANAZAWA
2019 Volume E102.A Issue 2 Pages 324
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS
• Yoshinao ISOBE, Hisabumi HATSUGAI, Akira TANAKA, Yutaka OIWA, Takanori ...
Type: PAPER
2019 Volume E102.A Issue 2 Pages 325-335
Published: February 01, 2019
Released: February 01, 2019
JOURNALS FREE ACCESS

This paper presents a formal approach for generating train timetables in a mesoscopic level that is more concrete than the macroscopic level, where each station is simply expressed in a black-box, and more abstract than the microscopic level, where the infrastructure in each station-area is expressed in detail. The accuracy of generated timetable and the computational effort for the generation is a trade-off. In this paper, we design a formal mesoscopic modeling language by analyzing real railways, for example Tazawako-line as the first step of this work. Then, we define the constraint formulae for generating train timetables with the help of SMT (Satisfiability Module Theories)-Solver, and explain our tool RW-Solver that is an implementation of the constraint formulae. Finally, we demonstrate how RW-Solver with the help of SMT-Solver can be used for generating timetables in a case study of Tazawako-line.

• Shingo YAMAGUCHI
Type: PAPER
2019 Volume E102.A Issue 2 Pages 336-342
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

Workflow nets (WF-nets for short) are a subclass of Petri nets and are used for modeling and analysis of workflows. Soundness is a criterion of logical correctness defined for WF-nets. A WF-net is said to be sound if it satisfies three conditions: (i) option to complete, (ii) proper completion, and (iii) no dead tasks. In this paper, focusing our analysis on acyclic free choice WF-nets, we revealed that (1) Conditions (i) and (ii) of soundness are respectively equivalent to the liveness and the boundedness of its short-circuited net; (2) The decision problem for each condition of soundness is co-NP-complete; and (3) If the short-circuited net has no disjoint paths from a transition to a place (or no disjoint paths from a place to a transition), each condition can be checked in polynomial time.

• Yuichi KAJIYAMA, Naoki HAYASHI, Shigemasa TAKAI
Type: PAPER
2019 Volume E102.A Issue 2 Pages 343-350
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

This paper proposes a consensus-based subgradient method under a common constraint set with switching undirected graphs. In the proposed method, each agent has a state and an auxiliary variable as the estimates of an optimal solution and accumulated information of past gradients of neighbor agents. We show that the states of all agents asymptotically converge to one of the optimal solutions of the convex optimization problem. The simulation results show that the proposed consensus-based algorithm with accumulated subgradient information achieves faster convergence than the standard subgradient algorithm.

• Naoki HAYASHI, Masaaki NAGAHARA
Type: PAPER
2019 Volume E102.A Issue 2 Pages 351-358
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

This paper proposes a novel distributed proximal minimization algorithm for constrained optimization problems over fixed strongly connected networks. At each iteration, each agent updates its own state by evaluating a proximal operator of its objective function under a constraint set and compensating the unbalancing due to unidirectional communications. We show that the states of all agents asymptotically converge to one of the optimal solutions. Numerical results are shown to confirm the validity of the proposed method.

• Koichi KOBAYASHI
Type: PAPER
2019 Volume E102.A Issue 2 Pages 359-364
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

In this paper, based on the policy of model predictive control, a new method of predictive pinning control is proposed for the consensus problem of multi-agent systems. Pinning control is a method that the external control input is added to some agents (pinning nodes), e.g., leaders. By the external control input, consensus to a certain target value (not the average of the initial states) and faster consensus are achieved. In the proposed method, the external control input is calculated by the controller node connected to only pinning nodes. Since the states of all agents are required in calculation of the external control input, communication delays must be considered. The proposed algorithm includes not only calculation of the external control input but also delay compensation. The effectiveness of the proposed method is presented by a numerical example.

• Takafumi GOTO, Koki TANAKA, Mitsuru NAKATA, Qi-Wei GE
Type: PAPER
2019 Volume E102.A Issue 2 Pages 365-371
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

An automorphism of a graph G=(V, E) is such a one-to-one correspondence from vertex set V to itself that all the adjacencies of the vertices are maintained. Given a subset S of V whose one-to-one correspondence is decided, if the vertices of V-S possess unique correspondence in all the automorphisms that satisfy the decided correspondence for S, S is called determiner set of G. Further, S is called minimal determiner set if no proper subset of S is a determiner set and called kernel set if determiner set S with the smallest number of elements. Moreover, a problem to judge whether or not S is a determiner set is called determiner set decision problem. The purpose of this research is to deal with determiner set decision problem. In this paper, we firstly give the definitions and properties related to determiner sets and then propose an algorithm JDS that judges whether a given S is a determiner set of G in polynomial computation time. Finally, we evaluate the proposed algorithm JDS by applying it to possibly find minimal determiner sets for 100 randomly generated graphs. As the result, all the obtained determiner sets are minimal, which implies JDS is a reasonably effective algorithm for the judgement of determiner sets.

• Koichi KOBAYASHI, Mifuyu KIDO, Yuh YAMASHITA
Type: PAPER
2019 Volume E102.A Issue 2 Pages 372-378
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

In this paper, a surveillance system by multiple agents, which is called a multi-agent surveillance system, is studied. A surveillance area is given by an undirected connected graph. Then, the optimal control problem for multi-agent surveillance systems (the optimal surveillance problem) is to find trajectories of multiple agents that travel each node as evenly as possible. In our previous work, this problem is reduced to a mixed integer linear programming problem. However, the computation time for solving it exponentially grows with the number of agents. To overcome this technical issue, a new model predictive control method for multi-agent surveillance systems is proposed. First, a procedure of individual optimization, which is a kind of approximate solution methods, is proposed. Next, a method to improve the control performance is proposed. In addition, an event-triggering condition is also proposed. The effectiveness of the proposed method is presented by a numerical example.

• Satoshi TAOKA, Toshimasa WATANABE
Type: PAPER
2019 Volume E102.A Issue 2 Pages 379-388
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

The k-edge-connectivity augmentation problem for a specified set of vertices (kECA-SV for short) is defined by “Given a graph G=(V, E) and a subset Γ ⊆ V, find a minimum set E' of edges such that G'=(V, EE') has at least k edge-disjoint paths between any pair of vertices in Γ.” Let σ be the edge-connectivity of Γ (that is, G has at least σ edge-disjoint paths between any pair of vertices in Γ). We propose an algorithm for (σ+1)ECA-SV which is done in O(|Γ|) maximum flow operations. Then the time complexity is O(σ2|Γ||V|+|E|) if a given graph is sparse, or O(|Γ||V||BG|log(|V|2/|BG|)+|E|) if dense, where |BG| is the number of pairs of adjacent vertices in G. Also mentioned is an O(|V||E|+|V|2 log |V|) time algorithm for a special case where σ is equal to the edge-connectivity of G and an O(|V|+|E|) time one for σ ≤ 2.

• Morikazu NAKAMURA, Takeshi TENGAN, Takeo YOSHIDA
Type: PAPER
2019 Volume E102.A Issue 2 Pages 389-398
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

This paper proposes a Petri net based mathematical programming approach to combinatorial optimization, in which we generate integer linear programming problems from Petri net models instead of the direct mathematical formulation. We treat two types of combinatorial optimization problems, ordinary problems and time-dependent problems. Firstly, we present autonomous Petri net modeling for ordinary optimization problems, where we obtain fundamental constraints derived from Petri net properties and additional problem-specific ones. Secondly, we propose a colored timed Petri net modeling approach to time-dependent problems, where we generate variables and constraints for time management and for resolving conflicts. Our Petri net approach can drastically reduce the difficulty of the mathematical formulation in a sense that (1) the Petri net modeling does not require deep knowledge of mathematical programming and technique of integer linear model formulations, (2) our automatic formulation allows us to generate large size of integer linear programming problems, and (3) the Petri net modeling approach is flexible for input parameter changes of the original problem.

• Jinglun LI, Shigemasa TAKAI
Type: LETTER
2019 Volume E102.A Issue 2 Pages 399-403
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

We consider a similarity control problem for discrete event systems modeled as nondeterministic automata. A nonblocking supervisor was synthesized in the previous work under the assumption that the event occurrence and the current state of the plant are observable. In this letter, we prove that the synthesized supervisor is a maximally permissive nonblocking one.

Regular Section
• Zhe LI, Yili XIA, Qian WANG, Wenjiang PEI, Jinguang HAO
Type: PAPER
Subject area: Digital Signal Processing
2019 Volume E102.A Issue 2 Pages 404-414
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

A novel time-series relationship among four consecutive real-valued single-tone sinusoid samples is proposed based on their linear prediction property. In order to achieve unbiased frequency estimates for a real sinusoid in white noise, based on the proposed four-point time-series relationship, a constrained least squares cost function is minimized based on the unit-norm principle. Closed-form expressions for the variance and the asymptotic expression for the variance of the proposed frequency estimator are derived, facilitating a theoretical performance comparison with the existing three-point counterpart, called as the reformed Pisarenko harmonic decomposer (RPHD). The region of performance advantage of the proposed four-point based constrained least squares frequency estimator over the RPHD is also discussed. Computer simulations are conducted to support our theoretical development and to compare the proposed estimator performance with the RPHD as well as the Cramer-Rao lower bound (CRLB).

• Shigeru NINAGAWA
Type: PAPER
Subject area: Nonlinear Problems
2019 Volume E102.A Issue 2 Pages 415-422
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

The Game of Life, a two-dimensional computationally universal cellular automaton, is known to exhibits 1/f noise in the evolutions starting from random configurations. In this paper we perform the spectral analysis on the computation process by a Turing machine constructed on the array of the Game of Life. As a result, the power spectrum averaged over the whole array has almost flat line at low frequencies and a lot of sharp peaks at high frequencies although some regions in which complicated behavior such as frequent memory rewriting occurs exhibit 1/f noise. This singular power spectrum is, however, easily turned into 1/f by slightly deforming the initial configuration of the Turing machine. These results emphasize the peculiarity of the computation process on the Game of Life that is never shared with the evolutions from random configurations. The Lyapunov exponents have positive values in three out of six trials and zero or negative values in other three trails. That means the computation process is essentially chaotic but it has capable of recovering a slight error in the configuration of the Turing machine.

• Xuehou TAN, Bo JIANG
Type: PAPER
Subject area: Algorithms and Data Structures
2019 Volume E102.A Issue 2 Pages 423-429
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

Two points x, y inside a simple polygon P are said to be mutually link-2 visible if there exists the third point zP such that z is visible from both x and y. The polygon P is link-2 LR-visible if there are two points s, t on the boundary of P such that every point on the clockwise boundary of P from s to t is link-2 visible from some point of the other boundary of P from t to s and vice versa. We give a characterization of link-2 LR-visibility polygons by generalizing the known result on LR-visibility polygons. A new idea is to extend the concepts of ray-shootings and components to those under notion of link-2 visibility. Then, we develop an O(n log n) time algorithm to determine whether a given polygon is link-2 LR-visible. Using the characterization of link-2 LR-visibility polygons, we further present an O(n log n) time algorithm for determining whether a polygonal region is searchable by a k-searcher, k ≥ 2. This improves upon the previous O(n2) time bound [9]. A polygonal region P is said to be searchable by a searcher if the searcher can detect (or see) an unpredictable intruder inside the region, no matter how fast the intruder moves. A k-searcher holds k flashlights and can see only along the rays of the flashlights emanating from his position.

• Song BIAN, Masayuki HIROMOTO, Takashi SATO
Type: PAPER
Subject area: Cryptography and Information Security
2019 Volume E102.A Issue 2 Pages 430-439
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

In this work, we provide the first practical secure email filtering scheme based on homomorphic encryption. Specifically, we construct a secure naïve Bayesian filter (SNBF) using the Paillier scheme, a partially homomorphic encryption (PHE) scheme. We first show that SNBF can be implemented with only the additive homomorphism, thus eliminating the need to employ expensive fully homomorphic schemes. In addition, the design space for specialized hardware architecture realizing SNBF is explored. We utilize a recursive Karatsuba Montgomery structure to accelerate the homomorphic operations, where multiplication of 2048-bit integers are carried out. Through the experiment, both software and hardware versions of the SNBF are implemented. On software, 104-105x runtime and 103x storage reduction are achieved by SNBF, when compared to existing fully homomorphic approaches. By instantiating the designed hardware for SNBF, a further 33x runtime and 1919x power reduction are achieved. The proposed hardware implementation classifies an average-length email in under 0.5s, which is much more practical than existing solutions.

• Takahiro OTA, Hiroyoshi MORITA, Akiko MANADA
Type: PAPER
Subject area: Information Theory
2019 Volume E102.A Issue 2 Pages 440-449
Published: February 01, 2019
Released: February 01, 2019
JOURNALS FREE ACCESS

The technique of lossless compression via substring enumeration (CSE) is a kind of enumerative code and uses a probabilistic model built from the circular string of an input source for encoding a one-dimensional (1D) source. CSE is applicable to two-dimensional (2D) sources, such as images, by dealing with a line of pixels of a 2D source as a symbol of an extended alphabet. At the initial step of CSE encoding process, we need to output the number of occurrences of all symbols of the extended alphabet, so that the time complexity increases exponentially when the size of source becomes large. To reduce computational time, we can rearrange pixels of a 2D source into a 1D source string along a space-filling curve like a Hilbert curve. However, information on adjacent cells in a 2D source may be lost in the conversion. To reduce the time complexity and compress a 2D source without converting to a 1D source, we propose a new CSE which can encode a 2D source in a block-by-block fashion instead of in a line-by-line fashion. The proposed algorithm uses the flat torus of an input 2D source as a probabilistic model instead of the circular string of the source. Moreover, we prove the asymptotic optimality of the proposed algorithm for 2D general sources.

• Yongbo XIA, Shiyuan HE, Shaoping CHEN
Type: PAPER
Subject area: Information Theory
2019 Volume E102.A Issue 2 Pages 450-457
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

Let d=2pm-1 be the Niho decimation over $\mathbb{F}_{p^{2m}}$ satisfying $\gcd(d,p^{2m}-1)=3$, where m is an odd positive integer and p is a prime with p ≡ 2(mod 3). The cross-correlation function between the p-ary m-sequence of period p2m-1 and its every d-decimation sequence with short period $\frac{p^{2m}-1}{3}$ is investigated. It is proved that for each d-decimation sequence, the cross-correlation function takes four values and the corresponding correlation distribution is completely determined. This extends the results of Niho and Helleseth for the case gcd(d, p2m-1)=1.

• Shinichi MOGAMI, Yoshiki MITSUI, Norihiro TAKAMUNE, Daichi KITAMURA, H ...
Type: LETTER
Subject area: Engineering Acoustics
2019 Volume E102.A Issue 2 Pages 458-463
Published: February 01, 2019
Released: February 01, 2019
JOURNALS FREE ACCESS

In this letter, we propose a new blind source separation method, independent low-rank matrix analysis based on generalized Kullback-Leibler divergence. This method assumes a time-frequency-varying complex Poisson distribution as the source generative model, which yields convex optimization in the spectrogram estimation. The experimental evaluation confirms the proposed method's efficacy.

• Qichun WANG, Yanjun LI
Type: LETTER
Subject area: Cryptography and Information Security
2019 Volume E102.A Issue 2 Pages 464-466
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

It is known that correlation-immune (CI) Boolean functions used in the framework of side channel attacks need to have low Hamming weights. In this letter, we determine all unknown values of the minimum Hamming weights of d-CI Boolean functions in n variables, for d ≤ 5 and n ≤ 13.

• Xiuping PENG, Hongbin LIN, Yanmin LIU, Xiaoyu CHEN, Xiaoxia NIU, Yubo ...
Type: LETTER
Subject area: Coding Theory
2019 Volume E102.A Issue 2 Pages 467-470
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

Two new families of balanced almost binary sequences with a single zero element of period L=2q are presented in this letter, where q=4d+1 is an odd prime number. These sequences have optimal autocorrelation value or optimal autocorrelation magnitude. Our constructions are based on cyclotomy and Chinese Remainder Theorem.

• Xiaoyu CHEN, Heru SU, Yubo LI, Xiuping PENG
Type: LETTER
Subject area: Coding Theory
2019 Volume E102.A Issue 2 Pages 471-475
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

In this letter, a construction of asymmetric Gaussian integer zero correlation zone (ZCZ) sequence sets is presented based on interleaving and filtering. The proposed approach can provide optimal or almost optimal single Gaussian integer ZCZ sequence sets. In addition, arbitrary two sequences from different sets have inter-set zero cross-correlation zone (ZCCZ). The resultant sequence sets can be used in the multi-cell QS-CDMA system to reduce the inter-cell interference and increase the transmission data.

• Nan SHA, Mingxi GUO, Yuanyuan GAO, Lihua CHEN, Kui XU
Type: LETTER
Subject area: Communication Theory and Signals
2019 Volume E102.A Issue 2 Pages 476-479
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

In this letter, a physical-layer network coding (PNC) scheme based on continuous phase modulation (CPM) signal using the titled-phase model, i.e., TIP-CPM-PNC, is presented, and the combined titled-phase state trellis for the superimposed CPM signal in TIP-CPM-PNC is discussed. Simulation results show that the proposed scheme with low decoding complexity can achieve the same error performance as CPM-PNC using the traditional-phase model.

• Zheng FANG, Tieyong CAO, Jibin YANG, Meng SUN
Type: LETTER
Subject area: Image
2019 Volume E102.A Issue 2 Pages 480-485
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

Saliency detection is widely used in many vision tasks like image retrieval, compression and person re-identification. The deep-learning methods have got great results but most of them focused more on the performance ignored the efficiency of models, which were hard to transplant into other applications. So how to design a efficient model has became the main problem. In this letter, we propose parallel feature network, a saliency model which is built on convolution neural network (CNN) by a parallel method. Parallel dilation blocks are first used to extract features from different layers of CNN, then a parallel upsampling structure is adopted to upsample feature maps. Finally saliency maps are obtained by fusing summations and concatenations of feature maps. Our final model built on VGG-16 is much smaller and faster than existing saliency models and also achieves state-of-the-art performance.

• An-shui YU, Kenji HARA, Kohei INOUE, Kiichi URAHAMA
Type: LETTER
Subject area: Image
2019 Volume E102.A Issue 2 Pages 486-489
Published: February 01, 2019
Released: February 01, 2019
JOURNALS RESTRICTED ACCESS

In this paper, we propose a method for enhancing the visibility of omnidirectional spherical images by enlarging the foreground and compressing the background without provoking a sense of visual incompatibility by using a simplified spring model.