We propose a novel framework for integrating beginners' machine operational experiences with those of experts' to obtain a detailed task model. Beginners can provide valuable information for operation guidance and task design; for example, from the operations that are easy or difficult for them, the mistakes they make, and the strategy they tend to choose. However, beginners' experiences often vary widely and are difficult to integrate directly. Thus, we consider an operational experience as a sequence of hand-machine interactions at hotspots. Then, a few experts' experiences and a sufficient number of beginners' experiences are unified using two aggregation steps that align and integrate sequences of interactions. We applied our method to more than 40 experiences of a sewing task. The results demonstrate good potential for modeling and obtaining important properties of the task.

The aim of this study is to calculate optimal walking routes in real space for users partaking in immersive virtual reality (VR) games without compromising their immersion. To this end, we propose a navigation system to automatically determine the route to be taken by a VR user to avoid collisions with surrounding obstacles. The proposed method is evaluated by simulating a real environment. It is verified to be capable of calculating and displaying walking routes to safely guide users to their destinations without compromising their VR immersion. In addition, while walking in real space while experiencing VR content, users can choose between 6-DoF (six degrees of freedom) and 3-DoF (three degrees of freedom). However, we expect users to prefer 3-DoF conditions, as they tend to walk longer while using VR content. In dynamic situations, when two pedestrians are added to a designated computer-generated real environment, it is necessary to calculate the walking route using moving body prediction and display the moving body in virtual space to preserve immersion.

The transition dynamics of a multistable tunnel-diode oscillator is characterized for modulating amplitude of outputted oscillatory signal. The base oscillator possesses fixed-point and limit-cycle stable points for a unique bias voltage. Switching these two stable points by external signal can render an efficient method for modulation of output amplitude. The time required for state transition is expected to be dominated by the aftereffect of the limiting point. However, it is found that its influence decreases exponentially with respect to the amplitude of external signal. Herein, we first describe numerically the pulse generation scheme with the transition dynamics of the oscillator and then validate it with several time-domain measurements using a test circuit.

This paper proposes a salient chromagram by removing local trend to improve cover song identification accuracy. The proposed salient chromagram emphasizes tonal contents of music, which are well-preserved between an original song and its cover version, while reducing the effects of timber difference. We apply the proposed salient chromagram to the sequence-alignment based cover song identification. Experiments on two cover song datasets confirm that the proposed salient chromagram improves the cover song identification accuracy.

The hardness in solving the shortest vector problem (SVP) is a fundamental assumption for the security of lattice-based cryptographic algorithms. In 2010, Micciancio and Voulgaris proposed an algorithm named the Gauss Sieve, which is a fast and heuristic algorithm for solving the SVP. Schneider presented another algorithm named the Ideal Gauss Sieve in 2011, which is applicable to a special class of lattices, called ideal lattices. The Ideal Gauss Sieve speeds up the Gauss Sieve by using some properties of the ideal lattices. However, the algorithm is applicable only if the dimension of the ideal lattice n is a power of two or n+1 is a prime. Ishiguro et al. proposed an extension to the Ideal Gauss Sieve algorithm in 2014, which is applicable only if the prime factor of n is 2 or 3. In this paper, we first generalize the dimensions that can be applied to the ideal lattice properties to when the prime factor of n is derived from 2, p or q for two primes p and q. To the best of our knowledge, no algorithm using ideal lattice properties has been proposed so far with dimensions such as: 20, 44, 80, 84, and 92. Then we present an algorithm that speeds up the Gauss Sieve for these dimensions. Our experiments show that our proposed algorithm is 10 times faster than the original Gauss Sieve in solving an 80-dimensional SVP problem. Moreover, we propose a rotation-based Gauss Sieve that is approximately 1.5 times faster than the Ideal Gauss Sieve.

A model extraction attack is a security issue in deep neural networks (DNNs). Information on a trained DNN model is an attractive target for an adversary not only in terms of intellectual property but also of security. Thus, an adversary tries to reveal the sensitive information contained in the trained DNN model from machine-learning services. Previous studies on model extraction attacks assumed that the victim provides a machine-learning cloud service and the adversary accesses the service through formal queries. However, when a DNN model is implemented on an edge device, adversaries can physically access the device and try to reveal the sensitive information contained in the implemented DNN model. We call these physical model extraction attacks model reverse-engineering (MRE) attacks to distinguish them from attacks on cloud services. Power side-channel analyses are often used in MRE attacks to reveal the internal operation from power consumption or electromagnetic leakage. Previous studies, including ours, evaluated MRE attacks against several types of DNN processors with power side-channel analyses. In this paper, information leakage from a systolic array which is used for the matrix multiplication unit in the DNN processors is evaluated. We utilized correlation power analysis (CPA) for the MRE attack and reveal weight parameters of a DNN model from the systolic array. Two types of the systolic array were implemented on field-programmable gate array (FPGA) to demonstrate that CPA reveals weight parameters from those systolic arrays. In addition, we applied an extended analysis approach called “chain CPA” for robust CPA analysis against the systolic arrays. Our experimental results indicate that an adversary can reveal trained model parameters from a DNN accelerator even if the DNN model parameters in the off-chip bus are protected with data encryption. Countermeasures against side-channel leaks will be important for implementing a DNN accelerator on a FPGA or application-specific integrated circuit (ASIC).

ISO/IEC standardizes several chosen ciphertext-secure key encapsulation mechanism (KEM) schemes in ISO/IEC 18033-2. However, all ISO/IEC KEM schemes are not quantum resilient. In this paper, we introduce new isogeny-based KEM schemes (i.e., CSIDH-ECIES-KEM and CSIDH-PSEC-KEM) by modifying Diffie-Hellman-based KEM schemes in ISO/IEC standards. The main advantage of our schemes are compactness. The key size and the ciphertext overhead of our schemes are smaller than these of SIKE, which is submitted to NIST's post-quantum cryptosystems standardization, for current security analyses. Moreover, though SIKE is proved in the classical random oracle model, CSIDH-PSEC-KEM is proved in the quantum random oracle model. Finally, we discuss difficulty to construct isogeny-based KEM from ISO/IEC KEM schemes in the standard model (i.e., ACE-KEM and FACE-KEM).

Resource limitations require that bugs be resolved efficiently. The bug modification process uses bug reports, which are generated from service user reports. Developers read these reports and fix bugs. Developers discuss bugs by posting comments directly in bug reports. Although several studies have investigated the initial report in bug reports, few have researched the comments. Our research focuses on bug reports. Currently, everyone is free to comment, but the bug fixing time may be affected by how to comment. Herein we investigate the topic of comments in bug reports. Mixed topics do not affect the bug fixing time. However, the bug fixing time tends to be shorter when the discussion length of the phenomenon is short.

Multivariate public key cryptosystem (MPKC) is one of the major post quantum cryptosystems (PQC), and the National Institute of Standards and Technology (NIST) recently selected four MPKCs as candidates of their PQC. The security of MPKC depends on the hardness of solving systems of algebraic equations over finite fields. In particular, the multivariate quadratic (MQ) problem is that of solving such a system consisting of quadratic polynomials and is regarded as an important research subject in cryptography. In the Fukuoka MQ challenge project, the hardness of the MQ problem is discussed, and algorithms for solving the MQ problem and the computational results obtained by these algorithms are reported. Algorithms for computing Gröbner basis are used as the main tools for solving the MQ problem. For example, the F4 algorithm and M4GB algorithm have succeeded in solving many instances of the MQ problem provided by the project. In this paper, based on the F4-style algorithm, we present an efficient algorithm to solve the MQ problems with dense polynomials generated in the Fukuoka MQ challenge project. We experimentally show that our algorithm requires less computational time and memory for these MQ problems than the F4 algorithm and M4GB algorithm. We succeeded in solving Type II and III problems of Fukuoka MQ challenge using our algorithm when the number of variables was 37 in both problems.

Artificial intelligence (AI), especially deep learning (DL), has been remarkable and applied to various industries. However, adversarial examples (AE), which add small perturbations to input data of deep neural networks (DNNs) for misclassification, are attracting attention. In this paper, we propose a novel black-box attack to craft AE using only processing time which is side-channel information of DNNs, without using training data, model architecture and parameters, substitute models or output probability. While, several existing black-box attacks use output probability, our attack exploits a relationship between the number of activated nodes and the processing time of DNNs. The perturbations for AE are decided by the differential processing time according to input data in our attack. We show experimental results in which our attack's AE increase the number of activated nodes and cause misclassification to one of the incorrect labels effectively. In addition, the experimental results highlight that our attack can evade gradient masking countermeasures which mask output probability to prevent crafting AE against several black-box attacks.

This paper proposes a transparent glass quartz antenna for 5G-millimeter-wave-connected vehicles and clarifies the characteristics of signal reception when the glass antennas are placed on the windows of a vehicle traveling in an urban environment. Synthetic fused quartz is a material particularly suited for millimeter-wave devices owing to its excellent low transmission loss. Realizing synthetic fused quartz devices requires accurate micromachining technology specialized for the material coupled with the material technology. This paper presents a transparent antenna comprising a thin mesh pattern on a quartz substrate for installation on a vehicle window. A comparison of distributed transparent antennas and an omnidirectional antenna shows that the relative received power of the distributed antenna system is higher than that of the omnidirectional antenna. In addition, results show that the power received is similar when using vertically and horizontally polarized antennas. The design is verified in a field test using transparent antennas on the windows of a real vehicle.

New boundary integral equations are proposed for two-port slab waveguides which satisfy single mode condition. The boundary integral equations are combined with the orthogonality of guided mode and non-guided field. They are solved by the standard boundary element method with no use of mode expansion technique. Reflection and transmission coefficients of guided mode are directly determined by the boundary element method. To validate the proposed method, step waveguides for TE wave incidence and triangular rib waveguides for TM wave incidence are investigated by numerical calculations.

A novel shuffle converter by using 3D waveguide of MCF (multi-core fiber)/SMF (single mode fiber) ribbon fan-in fan-out configuration towards over 1,000 port count optical matrix switch has been proposed. The shuffle converter enables to avoid waveguide crossing section in the optical matrix switch configuration, and the principle device showed sufficient crosstalk of less than -54.2 dB, and insertion loss of 2.1 dB successfully.

Fake media has been spreading due to remarkable advances in media processing and machine leaning technologies, causing serious problems in society. We are conducting a research project called Media Clone aimed at developing methods for protecting people from fake but skillfully fabricated replicas of real media called media clones. Such media can be created from fake information about a specific person. Our goal is to develop a trusted communication system that can defend against attacks of media clones. This paper describes some research results of the Media Clone project, in particular, various methods for protecting personal information against generating fake information. We focus on 1) fake information generation in the physical world, 2) anonymization and abstraction in the cyber world, and 3) modeling of media clone attacks.

Incident ticket classification plays an important role in the complex system maintenance. However, low classification accuracy will result in high maintenance costs. To solve this issue, this paper proposes a fuzzy output support vector machine (FOSVM) based incident ticket classification approach, which can be implemented in the context of both two-class SVMs and multi-class SVMs such as one-versus-one and one-versus-rest. Our purpose is to solve the unclassifiable regions of multi-class SVMs to output reliable and robust results by more fine-grained analysis. Experiments on both benchmark data sets and real-world ticket data demonstrate that our method has better performance than commonly used multi-class SVM and fuzzy SVM methods.

This paper proposes an id-eCK secure identity-based authenticated key exchange (ID-AKE) scheme, where the id-eCK security implies that a scheme resists against leakage of all combinations of master, static, and ephemeral secret keys except ones trivially break the security. Most existing id-eCK secure ID-AKE schemes require two symmetric pairing operations or a greater number of asymmetric pairing, which is faster than symmetric one, operations to establish a session key. However, our scheme is realized with a single asymmetric pairing operation for each party, and this is an advantage in efficiency. The proposed scheme is based on the ID-AKE scheme by McCullagh and Barreto, which is vulnerable to an active attack. To achieve id-eCK security, we apply the HMQV construction and the NAXOS technique to the McCullagh-Barreto scheme. The id-eCK security is proved under the external Diffie-Hellman for target group assumption and the q-gap-bilinear collision attack assumption.

According to the aging society, it is getting more important for software industry to secure human resources including senior developers. To enhance the performance of senior developers, we should clarify the strengths and weaknesses of senior developers, and based on that, we should reconsider software engineering education and development support tools. To a greater or lesser extent, many cognitive abilities would be affected by aging, and we focus on the human memory as one of such abilities. We performed preliminary analysis based on the assumption. In the preliminary experiment, we prepared programs in which the influence of human memory performance (i.e., the number of variables remembered in the short-term memory) on reading speed is different, and measured time for subjects to understand the programs. As a result, we observed that the code reading speed of senior subjects was slow, when they read programs in which the influence of human memory performance is larger.

We discuss herein whether an optical wireless communication (OWC) system can be a candidate for post 5G or 6G cellular communication. Almost once per decade, cellular mobile communication is transformed by a significant evolution, with each generation developing a distinctive concept or technology. Interestingly, similar trends have occurred in OWC systems based on visible light and light fidelity (Li-Fi). Unfortunately, OWC is currently relegated to a limited role in any 5G scenario, but the debate whether this is unavoidable has yet to be settled. Whether OWC is adopted post 5G or 6G is not the vital issue; rather, the aim should be that OWC coexists with 5G and 6G communication technologies. In working toward this goal, research and development in OWC will continue to extend its benefits and standardize its systems so that it can be widely deployed in the market. For example, given that a standard already exists for a visible-light beacon identifier and Li-Fi, a service using this standard should be developed to satisfy user demand. Toward this end, we propose herein a method for visible-light beacon identification that involves using a rolling shutter to receive visible-light communications with a smartphone camera. In addition, we introduce a rotary LED transmitter for image-sensor communication.

In high range resolution radar systems, the detection of range-spread target under correlated non-Gaussian clutter faces many problems. In this paper, a novel detector employing an autoregressive (AR) model is proposed to improve the detection performance. The algorithm is elaborately designed and analyzed considering the clutter characteristics. Numerical simulations and measurement data verify the effectiveness and advantages of the proposed detector for the range-spread target in spatially correlated non-Gaussian clutter.

In this paper, we propose a model of a diversity receiver which uses an antenna whose antenna pattern can periodically change. We also propose a minimum mean square error (MMSE) based interference cancellation method of the receiver which, in principle, can suffer from the interference in neighboring frequency bands. Since the antenna pattern changes according to the sum of sinusoidal waveforms with different frequencies, the received signals are received at the carrier frequency and the frequencies shifted from the carrier frequency by the frequency of the sinusoidal waveforms. The proposed diversity scheme combines the components in the frequency domain to maximize the signal-to-noise power ratio (SNR) and to maximize the diversity gain. We confirm that the bit error rate (BER) of the proposed receiver can be improved by increase in the number of arrival paths resulting in obtaining path diversity gain. We also confirm that the proposed MMSE based interference canceller works well when interference signals exist and achieves better BER performances than the conventional diversity receiver with maximum ratio combining.