Latest Issue of IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences
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Latest Issue of IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer SciencesENieice.orgieice.orgCopyright ieice.orgFOREWORD
http://search.ieice.org/bin/summary.php?id=e101-a_9_1280&category=A&lang=E&ref=rss&abst=&year=2018
Publication Date: 2018/09/01]]>An Advantage of the Vehicle to Vehicle Communication for an Automated Driving Car at the Encounter with an Ambulance
http://search.ieice.org/bin/summary.php?id=e101-a_9_1281&category=A&lang=E&ref=rss&abst=&year=2018
When the automated driving cars are in widespread usage, traffic will coexist with prioritized vehicles (e.g., ambulances, fire trucks, police vehicles) and automated driving cars. Automated driving cars are expected to be safer and lower stress than manual driving vehicles because of passengers paying less attention to driving. However, there are many challenges for automated driving cars to get along with surrounding transport participants. In particular, when an ambulance is driving into an intersection with the red traffic signal, the automated driving car is required to deal with a situation differently from normal traffic situations. In order to continue safe driving, it is necessary to recognize the approach of the ambulance at an earlier time. Possible means of recognizing ambulances include siren sound, rotating red lights and vehicle to vehicle communication. Based on actual traffic data, the authors created a mathematical model of deceleration for giving way and consider the status of suitable behavior by automated driving cars. The authors calculate the detection distance required to take suitable action. The results indicate that there are advantages in vehicle to vehicle communication in detecting ambulances by automated driving cars. Publication Date: 2018/09/01]]>Information Delivery Delay Reduction by Relay-Assisted Broadcast Transmission for ITS V2V Communications
http://search.ieice.org/bin/summary.php?id=e101-a_9_1290&category=A&lang=E&ref=rss&abst=&year=2018
V2V broadcast communication is not only promising for safety driving assistance but also enhancing automated driving ability by sharing information of vehicle moving behavior with other vehicles. However, an important issue is how to reduce information delivery delay and achieve dependable communication that is essential for automated vehicle control by machine. Since radio propagation often exhibits fading and shadowing on the road, V2V packet error happens probabilistically. Although repeated transmission method can enhance reliability of broadcast transmission, information delivery delay significantly increases as packet reception rate decreases. In order to reduce the delay, a relay-assisted broadcast transmission scheme is employed in this paper. The scheme can improve packet reception rate by path diversity and remarkably reduce average delivery delay due to repeated transmission. Performance with roadside relay stations considering urban environment with multiple intersections is evaluated through large-scale network simulation. The obtained results show that the average delivery delay is remarkably reduced by the relay-assist scheme to less than 20ms, which is less than a quarter of the direct V2V communication. Publication Date: 2018/09/01]]>Hardware Architecture for High-Speed Object Detection Using Decision Tree Ensemble
http://search.ieice.org/bin/summary.php?id=e101-a_9_1298&category=A&lang=E&ref=rss&abst=&year=2018
Visual object detection on embedded systems involves a multi-objective optimization problem in the presence of trade-offs between power consumption, processing performance, and detection accuracy. For a new Pareto solution with high processing performance and low power consumption, this paper proposes a hardware architecture for decision tree ensemble using multiple channels of features. For efficient detection, the proposed architecture utilizes the dimensionality of feature channels in addition to parallelism in image space and adopts task scheduling to attain random memory access without conflict. Evaluation results show that an FPGA implementation of the proposed architecture with an aggregated channel features pedestrian detector can process 229 million samples per second at 100MHz operation frequency while it requires a relatively small amount of resources. Consequently, the proposed architecture achieves 350fps processing performance for 1080P Full HD images and outperforms conventional object detection hardware architectures developed for embedded systems. Publication Date: 2018/09/01]]>Comfortable Intelligence for Evaluating Passenger Characteristics in Autonomous Wheelchairs
http://search.ieice.org/bin/summary.php?id=e101-a_9_1308&category=A&lang=E&ref=rss&abst=&year=2018
In recent years, autonomous driving technologies are being developed for vehicles and personal mobility devices including golf carts and autonomous wheelchairs for various use cases, not only outside areas but inside areas like shopping malls, hospitals and airpots. The main purpose of developing these autonomous vehicles is to avoid the traffic accidents caused by human errors, to assist people with walking, and to improve human comfort by relieving them from driving. Most relevant research focuses on the efficiency and safety of autonomous driving, however, in order to use by the widespread of people in the society, it is important to consider passenger comfort inside vehicles as well as safety and efficiency. Therefore, in this work, we emphasize the importance of considering passenger comfort in designing the control loop of autonomous navigation for the concept of comfortable intelligence in the future autonomous mobility. Moreover, passenger characteristics, in terms of ride comfort in an autonomous vehicle, have not been investigated with regard to safety and comfort, depending on each passenger's driving experience, habits, knowledge, personality, and preference. There are still few studies on the optimization of autonomous driving control reflecting passenger characteristics and different stress factors during the ride. In this study, passenger stress characteristics with different stress factors were objectively analyzed using physiological indices (heart rate and galvanic skin response sensors) during autonomous wheelchair usages. Two different experimental results from 12 participants suggest that there are always at least two types of passengers: one who experiences stress and the other who does not, depending on the stress factors considered. Moreover, with regard to the classification result for the stress reduction method, there are two types of passenger groups, for whom the solution method is, respectively, either effective or ineffective. Publication Date: 2018/09/01]]>Behavior Estimation Method Based on Movement Trajectory by the Position Information
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Motorcycles are driven in a road widely but must be driven carefully because they are easily damaged by obstacles, bumps or potholes in the road. Thus, motorcycle trajectories are valuable for detecting road abnormalities. The trajectories are usually obtained from GPS (Global Positioning System). However, errors often occur in GPS positioning. In this research, we will present a detection idea of the GPS error based on behavior estimation of riders. Moreover, we will propose a novel behavior estimation method. Publication Date: 2018/09/01]]>Detection of 3D Reflector Code on Guardrail by Using Infrared Laser Radar for Road Information Acquisition
http://search.ieice.org/bin/summary.php?id=e101-a_9_1320&category=A&lang=E&ref=rss&abst=&year=2018
In order to obtain road information, we propose an information acquisition method using infrared laser radar by detecting 3D reflector code on roadside. The infrared laser radar on vehicle scans the 3D reflector code on guardrail. Through experiments, we show that the proposed method is able to obtain road information by detecting 3D reflector code on guardrail. Publication Date: 2018/09/01]]>FOREWORD
http://search.ieice.org/bin/summary.php?id=e101-a_9_1323&category=A&lang=E&ref=rss&abst=&year=2018
Publication Date: 2018/09/01]]>Nash Equilibria in Combinatorial Auctions with Item Bidding and Subadditive Symmetric Valuations
http://search.ieice.org/bin/summary.php?id=e101-a_9_1324&category=A&lang=E&ref=rss&abst=&year=2018
We discuss Nash equilibria in combinatorial auctions with item bidding. Specifically, we give a characterization for the existence of a Nash equilibrium in a combinatorial auction with item bidding when valuations by n bidders satisfy symmetric and subadditive properties. By this characterization, we can obtain an algorithm for deciding whether a Nash equilibrium exists in such a combinatorial auction. Publication Date: 2018/09/01]]>Online Combinatorial Optimization with Multiple Projections and Its Application to Scheduling Problem
http://search.ieice.org/bin/summary.php?id=e101-a_9_1334&category=A&lang=E&ref=rss&abst=&year=2018
We consider combinatorial online prediction problems and propose a new construction method of efficient algorithms for the problems. One of the previous approaches to the problem is to apply online prediction method, in which two external procedures the projection and the metarounding are assumed to be implemented. In this work, we generalize the projection to multiple projections. As an application of our framework, we show an algorithm for an online job scheduling problem with a single machine with precedence constraints. Publication Date: 2018/09/01]]>An Efficient Pattern Matching Algorithm for Unordered Term Tree Patterns of Bounded Dimension
http://search.ieice.org/bin/summary.php?id=e101-a_9_1344&category=A&lang=E&ref=rss&abst=&year=2018
A term is a connected acyclic graph (unrooted unordered tree) pattern with structured variables, which are ordered lists of one or more distinct vertices. A variable of a term has a variable label and can be replaced with an arbitrary tree by hyperedge replacement according to the variable label. The dimension of a term is the maximum number of vertices in the variables of it. A term is said to be linear if each variable label in it occurs exactly once. Let T be a tree and t a linear term. In this paper, we study the graph pattern matching problem (GPMP) for T and t, which decides whether or not T is obtained from t by replacing variables in t with some trees. First we show that GPMP for T and t is NP-complete if the dimension of t is greater than or equal to 4. Next we give a polynomial time algorithm for solving GPMP for a tree of bounded degree and a linear term of bounded dimension. Finally we show that GPMP for a tree of arbitrary degree and a linear term of dimension 2 is solvable in polynomial time. Publication Date: 2018/09/01]]>Excluded Minors of Rank 3 for Orientability and Representability
http://search.ieice.org/bin/summary.php?id=e101-a_9_1355&category=A&lang=E&ref=rss&abst=&year=2018
We investigate excluded minor characterizations of two fundamental classes of matroids: orientable matroids and representable matroids. We prove (i) for any fixed field F, there exist infinitely many excluded minors of rank 3 for the union of the class of orientable matroids and the class of F-representable matroids, and (ii) for any fixed field F with characteristic 0, there exist infinitely many orientable excluded minors of rank 3 for intersection of the class of orientable matroids and the class of F-representable matroids. We show these statements by explicitly constructing infinite families of excluded minors. Publication Date: 2018/09/01]]>Enumerating All Spanning Shortest Path Forests with Distance and Capacity Constraints
http://search.ieice.org/bin/summary.php?id=e101-a_9_1363&category=A&lang=E&ref=rss&abst=&year=2018
This paper studies a variant of the graph partitioning problem, called the evacuation planning problem, which asks us to partition a target area, represented by a graph, into several regions so that each region contains exactly one shelter. Each region must be convex to reduce intersections of evacuation routes, the distance between each point to a shelter must be bounded so that inhabitants can quickly evacuate from a disaster, and the number of inhabitants assigned to each shelter must not exceed the capacity of the shelter. This paper formulates the convexity of connected components as a spanning shortest path forest for general graphs, and proposes a novel algorithm to tackle this multi-objective optimization problem. The algorithm not only obtains a single partition but also enumerates all partitions simultaneously satisfying the above complex constraints, which is difficult to be treated by existing algorithms, using zero-suppressed binary decision diagrams (ZDDs) as a compressed expression. The efficiency of the proposed algorithm is confirmed by the experiments using real-world map data. The results of the experiments show that the proposed algorithm can obtain hundreds of millions of partitions satisfying all the constraints for input graphs with a hundred of edges in a few minutes. Publication Date: 2018/09/01]]>Fast Enumeration of All Pareto-Optimal Solutions for 0-1 Multi-Objective Knapsack Problems Using ZDDs
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Finding Pareto-optimal solutions is a basic approach in multi-objective combinatorial optimization. In this paper, we focus on the 0-1 multi-objective knapsack problem, and present an algorithm to enumerate all its Pareto-optimal solutions, which improves upon the method proposed by Bazgan et al. Our algorithm is based on dynamic programming techniques using an efficient data structure called zero-suppressed binary decision diagram (ZDD), which handles a set of combinations compactly. In our algorithm, we utilize ZDDs for storing all the feasible solutions compactly, and pruning inessential partial solutions as quickly as possible. As an output of the algorithm, we can obtain a useful ZDD indexing all the Pareto-optimal solutions. The results of our experiments show that our algorithm is faster than the previous method for various types of three- and four-objective instances, which are difficult problems to solve. Publication Date: 2018/09/01]]>Efficient Enumeration of Induced Matchings in a Graph without Cycles with Length Four
http://search.ieice.org/bin/summary.php?id=e101-a_9_1383&category=A&lang=E&ref=rss&abst=&year=2018
In this study, we address a problem pertaining to the induced matching enumeration. An edge set M is an induced matching of a graph G=(V,E). The enumeration of matchings has been widely studied in literature; however, there few studies on induced matching. A straightforward algorithm takes O(Δ2) time for each solution that is coming from the time to generate a subproblem, where Δ is the maximum degree in an input graph. To generate a subproblem, an algorithm picks up an edge e and generates two graphs, the one is obtained by removing e from G, the other is obtained by removing e, adjacent edge to e, and edges adjacent to adjacent edge of e. Since this operation needs O(Δ2) time, a straightforward algorithm enumerates all induced matchings in O(Δ2) time per solution. We investigated local structures that enable us to generate subproblems within a short time and proved that the time complexity will be O(1) if the input graph is C4-free. A graph is C4-free if and only if none of its subgraphs have a cycle of length four. Publication Date: 2018/09/01]]>Enumerating Floorplans with Columns
http://search.ieice.org/bin/summary.php?id=e101-a_9_1392&category=A&lang=E&ref=rss&abst=&year=2018
Given an axis-aligned rectangle R and a set P of n points in the proper inside of R we wish to partition R into a set S of n+1 rectangles so that each point in P is on the common boundary between two rectangles in S. We call such a partition of R a feasible floorplan of R with respect to P. Intuitively, P is the locations of columns and a feasible floorplan is a floorplan in which no column is in the proper inside of a room, i.e., columns are allowed to be placed only on the partition walls between rooms. In this paper we give an efficient algorithm to enumerate all feasible floorplans of R with respect to P. The algorithm is based on the reverse search method, and enumerates all feasible floorplans in O(|SP|) time using O(n) space, where SP is the set of the feasible floorplans of R with respect to P, while the known algorithms need either O(n|SP|) time and O(n) space or O(log n|SP|) time and O(n3) space. Publication Date: 2018/09/01]]>Parameterized Algorithms to Compute Ising Partition Function
http://search.ieice.org/bin/summary.php?id=e101-a_9_1398&category=A&lang=E&ref=rss&abst=&year=2018
Computing the partition function of the Ising model on a graph has been investigated from both sides of computer science and statistical physics, with producing fertile results of P cases, FPTAS/FPRAS cases, inapproximability and intractability. Recently, measurement-based quantum computing as well as quantum annealing open up another bridge between two fields by relating a tree tensor network representing a quantum graph state to a rank decomposition of the graph. This paper makes this bridge wider in both directions. An $O^*(2^{ rac{omega}{2} bw(G)})$-time algorithm is developed for the partition function on n-vertex graph G with branch decomposition of width bw(G), where O* ignores a polynomial factor in n and ω is the matrix multiplication parameter less than 2.37287. Related algorithms of $O^*(4^{rw( ilde{G})})$ time for the tree tensor network are given which are of interest in quantum computation, given rank decomposition of a subdivided graph $ ilde{G}$ with width $rw( ilde{G})$. These algorithms are parameter-exponential, i.e., O*(cp) for constant c and parameter p, and such an algorithm is not known for a more general case of computing the Tutte polynomial in terms of bw(G) (the current best time is O*(min{2n, bw(G)O(bw(G))})) with a negative result in terms of the clique-width, related to the rank-width, under ETH. Publication Date: 2018/09/01]]>On Aggregating Two Metrics with Relaxed Triangle Inequalities by the Weighted Harmonic Mean
http://search.ieice.org/bin/summary.php?id=e101-a_9_1404&category=A&lang=E&ref=rss&abst=&year=2018
An important problem in mathematics and data science, given two or more metric spaces, is obtaining a metric of the product space by aggregating the source metrics using a multivariate function. In 1981, Borsík and Doboš solved the problem, and much progress has subsequently been made in generalizations of the problem. The triangle inequality is a key property for a bivariate function to be a metric. In the metric aggregation, requesting the triangle inequality of the resulting metric imposes the subadditivity on the aggregating function. However, in some applications, such as the image matching, a relaxed notion of the triangle inequality is useful and this relaxation may enlarge the scope of the aggregators to include some natural superadditive functions such as the harmonic mean. This paper examines the aggregation of two semimetrics (i.e. metrics with a relaxed triangle inequality) by the harmonic mean is studied and shows that such aggregation weakly preserves the relaxed triangle inequalities. As an application, the paper presents an alternative simple proof of the relaxed triangle inequality satisfied by the robust Jaccard-Tanimoto set dissimilarity, which was originally shown by Gragera and Suppakitpaisarn in 2016. Publication Date: 2018/09/01]]>The Stable Roommates Problem with Unranked Entries
http://search.ieice.org/bin/summary.php?id=e101-a_9_1412&category=A&lang=E&ref=rss&abst=&year=2018
The family of stable matching problems have been well-studied across a wide field of research areas, including economics, mathematics and computer science. In general, an instance of a stable matching problem is given by a set of participants who have expressed their preferences of each other, and asks to find a “stable” matching, that is, a pairing of the participants such that no unpaired participants prefer each other to their assigned partners. In the case of the Stable Roommates Problem (SR), it is known that given an even number n of participants, there might not exist a stable matching that pairs all of the participants, but there exist efficient algorithms to determine if this is possible or not, and if it is possible, produce such a matching. Common extensions of SR allow for the participants' preference lists to be incomplete, or include indifference. Allowing indifference in turn, gives rise to different possible definitions of stability, super, strong, and weak stability. While instances asking for super and strongly stable matching can be efficiently solved even if preference lists are incomplete, the case of weak stability is NP-complete. We examine a restricted case of indifference, introducing the concept of unranked entries. For this type of instances, we show that the problem of finding a weakly stable matching remains NP-complete even if each participant has a complete preference list with at most two unranked entries, or is herself unranked for up to three other participants. On the other hand, for instances where there are m acceptable pairs and there are in total k unranked entries in all of the participants' preference lists, we propose an O(2kn2)-time and polynomial space algorithm that finds a stable matching, or determines that none exists in the given instance. Publication Date: 2018/09/01]]>Rep-Cubes: Dissection of a Cube into Nets
http://search.ieice.org/bin/summary.php?id=e101-a_9_1420&category=A&lang=E&ref=rss&abst=&year=2018
Last year, a new notion of rep-cube was proposed. A rep-cube is a polyomino that is a net of a cube, and it can be divided into some polyominoes such that each of them can be folded into a cube. This notion was inspired by the notions of polyomino and rep-tile, which were introduced by Solomon W. Golomb. It was proved that there are infinitely many distinct rep-cubes. In this paper, we investigate this new notion and show further results. Publication Date: 2018/09/01]]>Computational Power of Threshold Circuits of Energy at most Two
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The energy of a threshold circuit C is defined to be the maximum number of gates outputting ones for an input assignment, where the maximum is taken over all the input assignments. In this paper, we study computational power of threshold circuits of energy at most two. We present several results showing that the computational power of threshold circuits of energy one and the counterpart of energy two are remarkably different. In particular, we give an explicit function which requires an exponential size for threshold circuits of energy one, but is computable by a threshold circuit of size just two and energy two. We also consider MOD functions and Generalized Inner Product functions, and show that these functions also require exponential size for threshold circuits of energy one, but are computable by threshold circuits of substantially less size and energy two. Publication Date: 2018/09/01]]>Attribute-Based Encryption for Range Attributes
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Attribute-Based Encryption (ABE) is an advanced form of public-key encryption where access control mechanisms based on attributes and policies are possible. In conventional ABE, attributes are specified as strings. However, there are certain applications where it is useful to specify attributes as numerical values and consider a predicate that determines if a certain numerical range would include a certain value. Examples of these types of attributes include time, position coordinate, person's age, rank, identity, and so on. In this paper, we introduce ABE for boolean formulae over Range Membership (ABE-RM). We show generic methods to convert conventional ABE to ABE-RM. Our generic conversions are efficient as they introduce only logarithmic overheads (in key and ciphertext sizes), as opposed to trivial methods, which would pose linear overheads. By applying our conversion to previous ABE schemes, we obtain new efficient and expressive ABE-RM schemes. Previous works that considered ABE with range attributes are specific and can only deal with either a single relation of range membership (Paterson and Quaglia at SCN'10, and Kasamatsu et al. at SCN'12), or limited classes of policies, namely, only AND-gates of range attributes (Shi et al. at IEEE S&P'07, and some subsequent work). Our schemes are generic and can deal with expressive boolean formulae. Publication Date: 2018/09/01]]>Generic Constructions for Fully Secure Revocable Attribute-Based Encryption
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Attribute-based encryption (ABE), a cryptographic primitive, realizes fine-grained access control. Because of its attractive functionality, many systems based on ABE have been constructed to date. In such cryptographic systems, revocation functionality is indispensable to handle withdrawal of users, secret key exposure, and others. Although many ABE schemes with various functionalities have been proposed, only a few of these are revocable ABE (RABE). In this paper, we propose two generic constructions of RABE from ABE. Our first construction employs the pair encoding framework (Attrapadung, EUROCRYPT 2014), and combines identity-based revocation and ABE via the generic conjunctive conversion of Attrapadung and Yamada (CT-RSA 2015). Our second construction converts ABE to RABE directly when ABE supports Boolean formulae. Because our constructions preserve functionalities of the underlying ABE, we can instantiate various fully secure RABE schemes for the first time, e.g., supporting regular languages, with unbounded attribute size and policy structure, and with constant-size ciphertext and secret key. Publication Date: 2018/09/01]]>More Constructions of Re-Splittable Threshold Public Key Encryption
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The concept of threshold public key encryption (TPKE) with the special property called key re-splittability (re-splittable TPKE, for short) was introduced by Hanaoka et al. (CT-RSA 2012), and used as one of the building blocks for constructing their proxy re-encryption scheme. In a re-splittable TPKE scheme, a secret key can be split into a set of secret key shares not only once, but also multiple times, and the security of the TPKE scheme is guaranteed as long as the number of corrupted secret key shares under the same splitting is smaller than the threshold. In this paper, we show several new constructions of a re-splittable TPKE scheme by extending the previous (ordinary) TPKE schemes. All of our proposed schemes are based on discrete logarithm (DL)-type assumptions. Therefore, our results suggest that key re-splittability is a very natural property for DL-type TPKE schemes. Publication Date: 2018/09/01]]>Meeting Tight Security for Multisignatures in the Plain Public Key Model
http://search.ieice.org/bin/summary.php?id=e101-a_9_1484&category=A&lang=E&ref=rss&abst=&year=2018
Multisignatures are digital signatures for a group consisting of multiple signers where each signer signs common documents via interaction with its co-signers and the data size of the resultant signatures for the group is independent of the number of signers. In this work, we propose a multisignature scheme, whose security can be tightly reduced to the CDH problem in bilinear groups, in the strongest security model where nothing more is required than that each signer has a public key, i.e., the plain public key model. Loosely speaking, our main idea for a tight reduction is to utilize a three-round interaction in a full-domain hash construction. Namely, we surmise that a full-domain hash construction with three-round interaction will become tightly secure under the CDH problem. In addition, we show that the existing scheme by Zhou et al. (ISC 2011) can be improved to a construction with a tight security reduction as an application of our proof framework. Publication Date: 2018/09/01]]>Pile-Shifting Scramble for Card-Based Protocols
http://search.ieice.org/bin/summary.php?id=e101-a_9_1494&category=A&lang=E&ref=rss&abst=&year=2018
Card-based cryptographic protocols provide secure multi-party computations using a deck of physical cards. The most important primitive of those protocols is the shuffling operation, and most of the existing protocols rely on uniform cyclic shuffles (such as the random cut and random bisection cut) in which each possible outcome is equally likely and all possible outcomes constitute a cyclic subgroup. However, a couple of protocols with non-uniform and/or non-cyclic shuffles were proposed by Koch, Walzer, and Härtel at Asiacrypt 2015. Compared to the previous protocols, their protocols require fewer cards to securely produce a hidden AND value, although to implement of such unconventional shuffles appearing in their protocols remains an open problem. This paper introduces “pile-shifting scramble,” which can be a secure implementation of those shuffles. To implement such unconventional shuffles, we utilize physical cases that can store piles of cards, such as boxes and envelopes. Therefore, humans are able to perform the shuffles using these everyday objects. Furthermore, we show that a certain class of non-uniform and/or non-cyclic shuffles having two possible outcomes can be implemented by the pile-shifting scramble. This also implies that we can improve upon the known COPY protocol using three card cases so that the number of cases required can be reduced to two. Publication Date: 2018/09/01]]>Toward Finite-Runtime Card-Based Protocol for Generating a Hidden Random Permutation without Fixed Points
http://search.ieice.org/bin/summary.php?id=e101-a_9_1503&category=A&lang=E&ref=rss&abst=&year=2018
In the research area of card-based secure computation, one of the long-standing open problems is a problem proposed by Crépeau and Kilian at CRYPTO 1993. This is to develop an efficient protocol using a deck of physical cards that generates uniformly at random a permutation with no fixed points (called a derangement), where the resulting permutation must be secret against the parties in the protocol. All the existing protocols for the problem have a common issue of lacking a guarantee to halt within a finite number of steps. In this paper, we investigate feasibility and infeasibility for the problem where both a uniformly random output and a finite runtime is required. First, we propose a way of reducing the original problem, which is to sample a uniform distribution over an inefficiently large set of the derangements, to another problem of sampling a non-uniform distribution but with a significantly smaller underlying set. This result will be a base of a new approach to the problem. On the other hand, we also give (assuming the abc conjecture), under a certain formal model, an asymptotic lower bound of the number of cards for protocols solving the problem using uniform shuffles only. This result would give a supporting evidence for the necessity of dealing with non-uniform distributions such as in the aforementioned first part of our result. Publication Date: 2018/09/01]]>Secure Grouping Protocol Using a Deck of Cards
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We consider a problem, which we call secure grouping, of dividing a number of parties into some subsets (groups) in the following manner: Each party has to know the other members of his/her group, while he/she may not know anything about how the remaining parties are divided (except for certain public predetermined constraints, such as the number of parties in each group). In this paper, we construct an information-theoretically secure protocol using a deck of physical cards to solve the problem, which is jointly executable by the parties themselves without a trusted third party. Despite the non-triviality and the potential usefulness of the secure grouping, our proposed protocol is fairly simple to describe and execute. Our protocol is based on algebraic properties of conjugate permutations. A key ingredient of our protocol is our new techniques to apply multiplication and inverse operations to hidden permutations (i.e., those encoded by using face-down cards), which would be of independent interest and would have various potential applications. Publication Date: 2018/09/01]]>Distribution of Digit Patterns in Multi-Value Sequence over the Odd Characteristic Field
http://search.ieice.org/bin/summary.php?id=e101-a_9_1525&category=A&lang=E&ref=rss&abst=&year=2018
The authors have proposed a multi-value sequence called an NTU sequence which is generated by a trace function and the Legendre symbol over a finite field. Most of the properties for NTU sequence such as period, linear complexity, autocorrelation, and cross-correlation have been theoretically shown in our previous work. However, the distribution of digit patterns, which is one of the most important features for security applications, has not been shown yet. In this paper, the distribution has been formulated with a theoretic proof by focusing on the number of 0's contained in the digit pattern. Publication Date: 2018/09/01]]>Computational Complexity of Usowan Puzzles
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Usowan is one of Nikoli's pencil puzzles. We study the computational complexity of Usowan puzzles. It is shown that deciding whether a given instance of the Usowan puzzle has a solution is NP-complete. Publication Date: 2018/09/01]]>A Maximal Local Maximum-Sum Segment Data Structure
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A linear-time constructible data structure for a real number sequence supporting O(1)-time queries of the maximal local maximum-sum segment of any contiguous subsequence containing any specific position is proposed, where a local maximum-sum segment is a segment whose maximum-sum segment is itself. Publication Date: 2018/09/01]]>Depth Two (n-2)-Majority Circuits for n-Majority
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We present an explicit construction of a MAJn-2 °MAJn-2 circuit computing MAJn for every odd n≥7. This gives a partial solution to an open problem by Kulikov and Podolskii (Proc. of STACS 2017, Article No.49). Publication Date: 2018/09/01]]>On Searching Linear Transformations for the Register R of MICKEY-Family Ciphers
http://search.ieice.org/bin/summary.php?id=e101-a_9_1546&category=A&lang=E&ref=rss&abst=&year=2018
MICKEY-family ciphers are lightweight cryptographic primitives and include a register R determined by two related maximal-period linear transformations. Provided that primitivity is efficiently decided in finite fields, it is shown by quantitative analysis that potential parameters for R can be found in probabilistic polynomial time. Publication Date: 2018/09/01]]>Cryptanalysis of Reduced Kreyvium
http://search.ieice.org/bin/summary.php?id=e101-a_9_1548&category=A&lang=E&ref=rss&abst=&year=2018
Kreyvium is a NLFSR-based stream cipher which is oriented to homomorphic-ciphertext compression. This is a variant of Trivium with 128-bit security. Designers have evaluated the security of Kreyvium and concluded that the resistance of Kreyvium to the conditional differential cryptanalysis is at least the resistance of Trivium, and even better. However, we consider that this attack is effective for reduced Kreyvium due to the structure of it. This paper shows the conditional differential cryptanalysis for Kreyvium, and we propose distinguishing and key recovery attacks. We show how to arrange differences and conditions to obtain good higher-order conditional differential characteristics. We use two types of higher-order conditional differential characteristics to find a distinguisher, e.g. the bias of higher-order conditional differential characteristics of a keystream and the probabilistic bias of them. In the first one, we obtain the distinguisher on Kreyvium with 730 rounds from 20-th order characteristics. In the second one, we obtain the distinguisher on Kreyvium with 899 rounds from 25-th order conditional differential characteristics. Moreover, we show the key recovery attack on Kreyvium with 736 rounds from 20-th order characteristics. We experimentally confirm all our attacks. The second distinguisher shows that we can obtain the distinguisher on Kreyvium with more rounds than the distinguisher on Trivium. Therefore, Kreyvium has a smaller security margin than Trivium for the conditional differential cryptanalysis. Publication Date: 2018/09/01]]>A Fully-Blind and Fast Image Quality Predictor with Convolutional Neural Networks
http://search.ieice.org/bin/summary.php?id=e101-a_9_1557&category=A&lang=E&ref=rss&abst=&year=2018
Image quality assessment (IQA) is an inherent problem in the field of image processing. Recently, deep learning-based image quality assessment has attracted increased attention, owing to its high prediction accuracy. In this paper, we propose a fully-blind and fast image quality predictor (FFIQP) using convolutional neural networks including two strategies. First, we propose a distortion clustering strategy based on the distribution function of intermediate-layer results in the convolutional neural network (CNN) to make IQA fully blind. Second, by analyzing the relationship between image saliency information and CNN prediction error, we utilize a pre-saliency map to skip the non-salient patches for IQA acceleration. Experimental results verify that our method can achieve the high accuracy (0.978) with subjective quality scores, outperforming existing IQA methods. Moreover, the proposed method is highly computationally appealing, achieving flexible complexity performance by assigning different thresholds in the saliency map. Publication Date: 2018/09/01]]>Noise Removal Based on Surface Approximation of Color Line
http://search.ieice.org/bin/summary.php?id=e101-a_9_1567&category=A&lang=E&ref=rss&abst=&year=2018
In a local region of a color image, the color distribution often takes the form of a linear line in the RGB space. This property is called “Color Line” and we propose a denoising method based on this property. When a noise is added on an image, its color distribution spreads from the Color Line. The denoising is achieved by reducing the spread. In conventional methods, Color Line is assumed to be only a single line, but actual distribution takes various shapes such as a single line, two lines, and a plane and so on. In our method, we estimate the distribution in more detail using plane approximation and denoise each patch by reducing the spread depending on the Color Line types. In this way, we can achieve better denoising results than a conventional method. Publication Date: 2018/09/01]]>An Improved Spread Clutter Estimated Canceller for Main-Lobe Clutter Suppression in Small-Aperture HFSWR
http://search.ieice.org/bin/summary.php?id=e101-a_9_1575&category=A&lang=E&ref=rss&abst=&year=2018
In small-aperture high frequency surface wave radar, the main-lobe clutter all can be seen as a more severe space spread clutter under the influence of the smaller array aperture. It compromises the detection performance of moving vessels, especially when the target is submerged in the clutter. To tackle this issue, an improved spread clutter estimated canceller, combining spread clutter estimated canceller, adaptive selection strategy of the optimal training samples and rotating spatial beam method, is presented to suppress main-lobe clutter in both angle domain and range domain. According to the experimental results, the proposed algorithm is shown to have far superior clutter suppression performance based on the real data. Publication Date: 2018/09/01]]>Precession Parameters Estimation of Space Rotationally Symmetric Targets Based on HRRP Sequences
http://search.ieice.org/bin/summary.php?id=e101-a_9_1580&category=A&lang=E&ref=rss&abst=&year=2018
Precession angle and precession period are significant parameters for identifying space micro-motion targets. To implement high-accuracy estimation of precession parameters without any prior knowledge about structure parameters of the target, a parameters extraction method based on HRRP sequences is proposed. The precession model of cone-shaped targets is established and analyzed firstly. Then the projection position of scattering centers on HRRP induced by precession is indicated to be approximate sinusoidal migration. Sequences of scattering centers are associated by sinusoid extraction algorithm. Precession angle and precession period are estimated utilizing error function optimization at last. Simulation results under various SNR levels based on electromagnetic calculation data demonstrate validity of the proposed method. Publication Date: 2018/09/01]]>Modified Generalized Sidelobe Canceller for Nonuniform Linear Array Radar Space-Time Adaptive Processing
http://search.ieice.org/bin/summary.php?id=e101-a_9_1585&category=A&lang=E&ref=rss&abst=&year=2018
This letter addresses the problem of space-time adaptive processing (STAP) for airborne nonuniform linear array (NLA) radar using a generalized sidelobe canceller (GSC). Due to the difficulty of determining the spatial nulls for the NLAs, it is a problem to obtain a valid blocking matrix (BM) of the GSC directly. In order to solve this problem and improve the STAP performance, a BM modification method based on the modified Gram-Schmidt orthogonalization algorithm is proposed. The modified GSC processor can achieve the optimal STAP performance and as well a faster convergence rate than the orthogonal subspace projection method. Numerical simulations validate the effectiveness of the proposed methods. Publication Date: 2018/09/01]]>Output Feedback Consensus of Nonlinear Multi-Agent Systems under a Directed Network with a Time Varying Communication Delay
http://search.ieice.org/bin/summary.php?id=e101-a_9_1588&category=A&lang=E&ref=rss&abst=&year=2018
The output feedback consensus problem of nonlinear multi-agent systems under a directed network with a time varying communication delay is studied. In order to deal with this problem, the dynamic output feedback controller with an additional low gain parameter that compensates for the effect of nonlinearity and a communication delay is proposed. Also, it is shown that under some assumptions, the proposed controller can always solve the output feedback consensus problem even in the presence of an arbitrarily large communication delay. Publication Date: 2018/09/01]]>A Fused Continuous Floating-Point MAC on FPGA
http://search.ieice.org/bin/summary.php?id=e101-a_9_1594&category=A&lang=E&ref=rss&abst=&year=2018
In this letter, we present a novel single-precision floating-point multiply-accumulator (FNA-MAC) to achieve lower hardware resource, reduced computing latency and improved computing accuracy for continuous dot product operations. By further fusing the normalization and alignment in the traditional FMA algorithm, the proposed architecture eliminates the first N-1 normalization and rounding operations for an N-point dot product, and preserves the precision of interim results in a significant bit size that is twice of that in the traditional methods. The normalization and rounding of the final result is processed at the cost of consuming an additional multiply-add operation. The simulation results show that the improvement in computational accuracy is significant. Meanwhile, when comparing to a recently published FMA design, the proposed FNA-MAC can reduce the slice look-up table/flip-flop resource and computing latency by a fact of 18%, 33.3%, respectively. Publication Date: 2018/09/01]]>On LCD MRD Codes
http://search.ieice.org/bin/summary.php?id=e101-a_9_1599&category=A&lang=E&ref=rss&abst=&year=2018
We investigate linear complementary dual (LCD) rank-metric codes in this paper. We construct a class of LCD generalized Gabidulin codes by a self-dual basis of an extension field over the base field. Moreover, a class of LCD MRD codes, which are obtained by Cartesian products of a generalized Gabidulin code, is constructed. Publication Date: 2018/09/01]]>Energy Efficient Resource Allocation for Downlink Cooperative Non-Orthogonal Multiple Access Systems
http://search.ieice.org/bin/summary.php?id=e101-a_9_1603&category=A&lang=E&ref=rss&abst=&year=2018
In this letter, we study the resource allocation for the downlink cooperative non-orthogonal multiple access (NOMA) systems based on the amplifying-and-forward protocol relay transmission. A joint power allocation and amplification gain selection scheme are proposed. Fractional programming and the iterative algorithm based on the Lagrangian multiplier are used to allocate the transmit power to maximize the energy efficiency (EE) of the systems. Simulation results show that the proposed scheme can achieve higher energy efficiency compared with the minimum power transmission (MPT-NOMA) scheme and the conventional OMA scheme. Publication Date: 2018/09/01]]>Compressive Phase Retrieval Realized by Combining Generalized Approximate Message Passing with Cartoon-Texture Model
http://search.ieice.org/bin/summary.php?id=e101-a_9_1608&category=A&lang=E&ref=rss&abst=&year=2018
Generalized approximate message passing (GAMP) can be applied to compressive phase retrieval (CPR) with excellent phase-transition behavior. In this paper, we introduced the cartoon-texture model into the denoising-based phase retrieval GAMP(D-prGAMP), and proposed a cartoon-texture model based D-prGAMP (C-T D-prGAMP) algorithm. Then, based on experiments and analyses on the variations of the performance of D-PrGAMP algorithms with iterations, we proposed a 2-stage D-prGAMP algorithm, which makes tradeoffs between the C-T D-prGAMP algorithm and general D-prGAMP algorithms. Finally, facing the non-convergence issues of D-prGAMP, we incorporated adaptive damping to 2-stage D-prGAMP, and proposed the adaptively damped 2-stage D-prGAMP (2-stage ADD-prGAMP) algorithm. Simulation results show that, runtime of 2-stage D-prGAMP is relatively equivalent to that of BM3D-prGAMP, but 2-stage D-prGAMP can achieve higher image reconstruction quality than BM3D-prGAMP. 2-stage ADD-prGAMP spends more reconstruction time than 2-stage D-prGAMP and BM3D-prGAMP. But, 2-stage ADD-prGAMP can achieve PSNRs 0.2∼3dB higher than those of 2-stage D-prGAMP and 0.3∼3.1dB higher than those of BM3D-prGAMP. Publication Date: 2018/09/01]]>