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[Keyword] generator(176hit)

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  • A Single-Inverter-Based True Random Number Generator with On-Chip Clock-Tuning-Based Entropy Calibration Circuit

    Xingyu WANG  Ruilin ZHANG  Hirofumi SHINOHARA  

     
    PAPER

      Pubricized:
    2023/07/21
      Vol:
    E107-A No:1
      Page(s):
    105-113

    This paper introduces an inverter-based true random number generator (I-TRNG). It uses a single CMOS inverter to amplify thermal noise multiple times. An adaptive calibration mechanism based on clock tuning provides robust operation across a wide range of supply voltage 0.5∼1.1V and temperature -40∼140°C. An 8-bit Von-Neumann post-processing circuit (VN8W) is implemented for maximum raw entropy extraction. In a 130nm CMOS technology, the I-TRNG entropy source only occupies 635μm2 and consumes 0.016pJ/raw-bit at 0.6V. The I-TRNG occupies 13406μm2, including the entropy source, adaptive calibration circuit, and post-processing circuit. The minimum energy consumption of the I-TRNG is 1.38pJ/bit at 0.5V, while passing all NIST 800-22 and 800-90B tests. Moreover, an equivalent 15-year life at 0.7V, 25°C is confirmed by an accelerated NBTI aging test.

  • Effect of Return Current Cable in Three Different Calibration Environments on Ringing Damped Oscillations of Contact Discharge Current Waveform from ESD Generator

    Yukihiro TOZAWA  Takeshi ISHIDA  Jiaqing WANG  Osamu FUJIWARA  

     
    PAPER-Electromagnetic Compatibility(EMC)

      Pubricized:
    2023/09/06
      Vol:
    E106-B No:12
      Page(s):
    1455-1462

    Measurements of contact discharge current waveforms from an ESD generator with a test voltage of 4kV are conducted with the IEC specified arrangement of a 2m long return current cable in different three calibration environments that all comply with the IEC calibration standard to identify the occurrence source of damped oscillations (ringing), which has remained unclear since contact discharge testing was first adopted in 1989 IEC publication 801-2. Their frequency spectra are analyzed comparing with the spectrum calculated from the ideal contact discharge current waveform without ringing (IEC specified waveform) offered in IEC 61000-4-2 and the spectra derived from a simplified equivalent circuit based on the IEC standard in combination with the measured input impedances of one-ended grounding return current cable with the same arrangement in the same calibration environment as those for the current measurements. The results show that the measured contact discharge waveforms have ringing around the IEC specified waveform after the falling edge of the peak, causing their spectra from 20MHz to 200MHz, but the spectra from 40MHz to 200MHz significantly differ depending on the calibration environments even for the same cable arrangement, which do not almost affect the spectra from 20MHz to 40MHz and over 200MHz. In the calibration environment under the cable arrangement close to the reference ground, the spectral shapes of the measured contact discharge currents and their frequencies of the multiple peaks and dips roughly correspond to the spectral distributions calculated from the simplified equivalent circuit using the measured cable input impedances. These findings reveal that the root cause of ringing is mainly due to the resonances of the return current cable, and calibration environment under the cable arrangement away from the reference ground tends to mitigate the cable resonances.

  • Design and Implementation of an On-Line Quality Control System for Latch-Based True Random Number Generator

    Naoki FUJIEDA  Shuichi ICHIKAWA  Ryusei OYA  Hitomi KISHIBE  

     
    PAPER

      Pubricized:
    2023/03/24
      Vol:
    E106-D No:12
      Page(s):
    1940-1950

    This paper presents a design and an implementation of an on-line quality control method for a TRNG (True Random Number Generator) on an FPGA. It is based on a TRNG with RS latches and a temporal XOR corrector, which can make a trade-off between throughput and randomness quality by changing the number of accumulations by XOR. The goal of our method is to increase the throughput within the range of keeping the quality of output random numbers. In order to detect a sign of the loss of quality from the TRNG in parallel with random number generation, our method distinguishes random bitstrings to be tested from those to be output. The test bitstring is generated with the fewer number of accumulations than that of the output bitstring. The number of accumulations will be increased if the test bitstring fails in the randomness test. We designed and evaluated a prototype of on-line quality control system, using a Zynq-7000 FPGA SoC. The results indicate that the TRNG with the proposed method achieved 1.91-2.63 Mbits/s of throughput with 16 latches, following the change of the quality of output random numbers. The total number of logic elements in the prototype system with 16 latches was comparable to an existing system with 256 latches, without quality control capabilities.

  • On Locality of Some Binary LCD Codes

    Ruipan YANG  Ruihu LI  Qiang FU  

     
    PAPER-Coding Theory

      Pubricized:
    2023/04/05
      Vol:
    E106-A No:10
      Page(s):
    1330-1335

    The design of codes for distributed storage systems that protects from node failures has been studied for years, and locally repairable code (LRC) is such a method that gives a solution for fast recovery of node failures. Linear complementary dual code (LCD code) is useful for preventing malicious attacks, which helps to secure the system. In this paper, we combine LRC and LCD code by integration of enhancing security and repair efficiency, and propose some techniques for constructing LCD codes with their localities determined. On the basis of these methods and inheriting previous achievements of optimal LCD codes, we give optimal or near-optimal [n, k, d;r] LCD codes for k≤6 and n≥k+1 with relatively small locality, mostly r≤3. Since all of our obtained codes are distance-optimal, in addition, we show that the majority of them are r-optimal and the other 63 codes are all near r-optimal, according to CM bound.

  • Reliable and Efficient Chip-PCB Hybrid PUF and Lightweight Key Generator

    Yuanzhong XU  Tao KE  Wenjun CAO  Yao FU  Zhangqing HE  

     
    PAPER-Electronic Circuits

      Pubricized:
    2023/03/10
      Vol:
    E106-C No:8
      Page(s):
    432-441

    Physical Unclonable Function (PUF) is a promising lightweight hardware security primitive that can extract device fingerprints for encryption or authentication. However, extracting fingerprints from either the chip or the board individually has security flaws and cannot provide hardware system-level security. This paper proposes a new Chip-PCB hybrid PUF(CPR PUF) in which Weak PUF on PCB is combined with Strong PUF inside the chip to generate massive responses under the control of challenges of on-chip Strong PUF. This structure tightly couples the chip and PCB into an inseparable and unclonable unit thus can verify the authenticity of chip as well as the board. To improve the uniformity and reliability of Chip-PCB hybrid PUF, we propose a lightweight key generator based on a reliability self-test and debiasing algorithm to extract massive stable and secure keys from unreliable and biased PUF responses, which eliminates expensive error correction processes. The FPGA-based test results show that the PUF responses after robust extraction and debiasing achieve high uniqueness, reliability, uniformity and anti-counterfeiting features. Moreover, the key generator greatly reduces the execution cost and the bit error rate of the keys is less than 10-9, the overall security of the key is also improved by eliminating the entropy leakage of helper data.

  • Activating Dipolar-Energy-Based Triboelectric Power Generation Using Pyromellitic Dianhydride-4,4'-Oxydianiline Polyimide at Elevated Temperature

    Dai TAGUCHI  Takaaki MANAKA  Mitsumasa IWAMOTO  

     
    PAPER

      Pubricized:
    2022/10/26
      Vol:
    E106-C No:6
      Page(s):
    202-207

    Triboelectric generators have been attracting much attention as electrical power sources in scientific communities and industries. Based on dielectric physics, two microscopic routes are available as current sources: One is charge displacement and the other is dipolar rotation. We have been investigating these routes as power sources for triboelectric generation. In other words, dipolar energy transfer process during a course of depolarization has the potentiality to be utilized as triboelectric generator. In this paper, we show that polyimide polymer film with permanent dipoles, i.e., PMDA-ODA polyimide, can provide current source capacity enhanced at elevated temperature, which is in good agreement with our idea based on dipolar energy mode of triboelectric generator. That is, permanent dipoles rotate quickly at elevated temperature, and act as an enhanced current source in the dipolar energy source model of triboelectric generator.

  • Combinatorial Structures Behind Binary Generalized NTU Sequences

    Xiao-Nan LU  

     
    LETTER-Cryptography and Information Security

      Pubricized:
    2022/06/15
      Vol:
    E106-A No:3
      Page(s):
    440-444

    This paper concentrates on a class of pseudorandom sequences generated by combining q-ary m-sequences and quadratic characters over a finite field of odd order, called binary generalized NTU sequences. It is shown that the relationship among the sub-sequences of binary generalized NTU sequences can be formulated as combinatorial structures called Hadamard designs. As a consequence, the combinatorial structures generalize the group structure discovered by Kodera et al. (IEICE Trans. Fundamentals, vol.E102-A, no.12, pp.1659-1667, 2019) and lead to a finite-geometric explanation for the investigated group structure.

  • Output Power Characterization of Flexible Thermoelectric Power Generators

    Daiki KANSAKU  Nobuhiro KAWASE  Naoki FUJIWARA  Faizan KHAN  Arockiyasamy Periyanayaga KRISTY  Kuruvankatil Dharmajan NISHA  Toshitaka YAMAKAWA  Kazushi IKEDA  Yasuhiro HAYAKAWA  Kenji MURAKAMI  Masaru SHIMOMURA  Hiroya IKEDA  

     
    BRIEF PAPER

      Pubricized:
    2022/04/21
      Vol:
    E105-C No:10
      Page(s):
    639-642

    To facilitate the reuse of environmental waste heat in our society, we have developed high-efficiency flexible thermoelectric power generators (TEPGs). In this study, we investigated the thermoelectromotive force (TEMF) and output power of a prototype device with 50 pairs of Π-type structures using a homemade measurement system for flexible TEPGs in order to evaluate their characteristics along the thickness direction. The prototype device consisted of C fabrics (CAFs) used as p-type materials, NiCu fabrics (NCFs) used as n-type materials, and Ag fabrics (AGFs) used as metal electrodes. Applying a temperature difference of 5K, we obtained a TEMF of 150μV and maximum output power of 6.4pW. The obtained TEMF was smaller than that expected from the Seebeck coefficients of each fabric, which is considered to be mainly because of the influence of contact thermal resistance at the semiconductor-fabric/AGF interfaces.

  • Electromotive Force of Piezoelectric/Thermoelectric-Combined Power Generator under Vibration and Temperature Gradient

    Naoki KAWAMURA  Ryoya SUZUKI  Kotomu NAITO  Yasuhiro HAYAKAWA  Kenji MURAKAMI  Masaru SHIMOMURA  Hiroya IKEDA  

     
    BRIEF PAPER

      Pubricized:
    2022/04/21
      Vol:
    E105-C No:10
      Page(s):
    635-638

    We have investigated the electromotive force (EMF) of a composite sample consisting of a Π-type thermoelectric power generation structure with a pair of n- and p-type Si wafers and piezoelectric devices in order to collect electricity from vibration energy and thermal energy, simultaneously. The observed EMF was obtained by superimposing the oscillating EMF of vibration energy on the constant EMF of thermal energy. Therefore, we have improved the composite sample with diodes for rectifying the oscillating EMF. As a result, the full-wave rectification and the preservation of EMF amplitude were realized. From the frequency dependence, it was found that the dielectric loss of the piezoelectric device influences the amplitude and the time delay in the EMF.

  • High Accuracy Test Techniques with Fine Pattern Generator and Ramp Test Circuit for CMOS Image Sensor

    Fukashi MORISHITA  Wataru SAITO  Norihito KATO  Yoichi IIZUKA  Masao ITO  

     
    PAPER

      Pubricized:
    2022/01/14
      Vol:
    E105-C No:7
      Page(s):
    316-323

    This paper proposes novel test techniques for high accuracy measurement of ADCs and a ramp generator on a CMOS image sensor (CIS) chip. The test circuit for the ADCs has a dual path and has an ability of multi-functional fine pattern generator that can define any input for each column to evaluate CIS specific characteristics electrically. The test circuit for the ramp generator can realize an on-chip current cell test and reject the current cell failure within 1LSB accuracy. We fabricated the test sensor using 55nm CIS process and measured the IP characteristics. Measured results show INL of 14.6LSB, crosstalk of 14.9LSB and column interference noise of 5.4LSB. These measured results agree with the designed values. By using this technique, we confirmed the accurate ADC measurement can be realized without being affected by the ambiguity of the optical input.

  • Evaluation of a True Random Number Generator Utilizing Timing Jitters in RSFQ Logic Circuits Open Access

    Kenta SATO  Naonori SEGA  Yuta SOMEI  Hiroshi SHIMADA  Takeshi ONOMI  Yoshinao MIZUGAKI  

     
    BRIEF PAPER

      Pubricized:
    2022/01/19
      Vol:
    E105-C No:6
      Page(s):
    296-299

    We experimentally evaluated random number sequences generated by a superconducting hardware random number generator composed of a Josephson-junction oscillator, a rapid-single-flux-quantum (RSFQ) toggle flip-flop (TFF), and an RSFQ AND gate. Test circuits were fabricated using a 10 kA/cm2 Nb/AlOx/Nb integration process. Measurements were conducted in a liquid helium bath. The random numbers were generated for a trigger frequency of 500 kHz under the oscillating Josephson-junction at 29 GHz. 26 random number sequences of 20 kb length were evaluated for bias voltages between 2.0 and 2.7 mV. The NIST FIPS PUBS 140-2 tests were used for the evaluation. 100% pass rates were confirmed at the bias voltages of 2.5 and 2.6 mV. We found that the Monobit test limited the pass rates. As numerical simulations suggested, a detailed evaluation for the probability of obtaining “1” demonstrated the monotonical dependence on the bias voltage.

  • Cyclic Shift Problems on Graphs

    Kwon Kham SAI  Giovanni VIGLIETTA  Ryuhei UEHARA  

     
    PAPER

      Pubricized:
    2021/10/08
      Vol:
    E105-D No:3
      Page(s):
    532-540

    We study a new reconfiguration problem inspired by classic mechanical puzzles: a colored token is placed on each vertex of a given graph; we are also given a set of distinguished cycles on the graph. We are tasked with rearranging the tokens from a given initial configuration to a final one by using cyclic shift operations along the distinguished cycles. We call this a cyclic shift puzzle. We first investigate a large class of graphs, which generalizes several classic cyclic shift puzzles, and we give a characterization of which final configurations can be reached from a given initial configuration. Our proofs are constructive, and yield efficient methods for shifting tokens to reach the desired configurations. On the other hand, when the goal is to find a shortest sequence of shifting operations, we show that the problem is NP-hard, even for puzzles with tokens of only two different colors.

  • Random Numbers Generated by the Oscillator Sampling Method as a Renewal Process

    Masahiro KAMINAGA  

     
    LETTER-Cryptography and Information Security

      Pubricized:
    2021/08/24
      Vol:
    E105-A No:2
      Page(s):
    118-121

    In this paper, the random numbers generated by a true random number generator, using the oscillator sampling method, are formulated using a renewal process, and this formulation is used to demonstrate the uniformity of the random numbers and the independence between different bits. Using our results, a lower bound for the speed of random number generation could easily be identified, according to the required statistical quality.

  • A DLL-Based Body Bias Generator with Independent P-Well and N-Well Biasing for Minimum Energy Operation

    Kentaro NAGAI  Jun SHIOMI  Hidetoshi ONODERA  

     
    PAPER

      Pubricized:
    2021/04/20
      Vol:
    E104-C No:10
      Page(s):
    617-624

    This paper proposes an area- and energy-efficient DLL-based body bias generator (BBG) for minimum energy operation that controls p-well and n-well bias independently. The BBG can minimize total energy consumption of target circuits under a skewed process condition between nMOSFETs and pMOSFETs. The proposed BBG is composed of digital cells compatible with cell-based design, which enables energy- and area-efficient implementation without additional supply voltages. A test circuit is implemented in a 65-nm FDSOI process. Measurement results using a 32-bit RISC processor on the same chip show that the proposed BBG can reduce energy consumption close to a minimum within a 3% energy loss. In this condition, energy and area overheads of the BBG are 0.2% and 0.12%, respectively.

  • Energy-Efficient Post-Processing Technique Having High Extraction Efficiency for True Random Number Generators Open Access

    Ruilin ZHANG  Xingyu WANG  Hirofumi SHINOHARA  

     
    PAPER

      Pubricized:
    2021/01/28
      Vol:
    E104-C No:7
      Page(s):
    300-308

    In this paper, we describe a post-processing technique having high extraction efficiency (ExE) for de-biasing and de-correlating a random bitstream generated by true random number generators (TRNGs). This research is based on the N-bit von Neumann (VN_N) post-processing method. It improves the ExE of the original von Neumann method close to the Shannon entropy bound by a large N value. However, as the N value increases, the mapping table complexity increases exponentially (2N), which makes VN_N unsuitable for low-power TRNGs. To overcome this problem, at the algorithm level, we propose a waiting strategy to achieve high ExE with a small N value. At the architectural level, a Hamming weight mapping-based hierarchical structure is used to reconstruct the large mapping table using smaller tables. The hierarchical structure also decreases the correlation factor in the raw bitstream. To develop a technique with high ExE and low cost, we designed and fabricated an 8-bit von Neumann with waiting strategy (VN_8W) in a 130-nm CMOS. The maximum ExE of VN_8W is 62.21%, which is 2.49 times larger than the ExE of the original von Neumann. NIST SP 800-22 randomness test results proved the de-biasing and de-correlation abilities of VN_8W. As compared with the state-of-the-art optimized 7-element iterated von Neumann, VN_8W achieved more than 20% energy reduction with higher ExE. At 0.45V and 1MHz, VN_8W achieved the minimum energy of 0.18pJ/bit, which was suitable for sub-pJ low energy TRNGs.

  • A True Random Number Generator Method Embedded in Wireless Communication Systems

    Toshinori SUZUKI  Masahiro KAMINAGA  

     
    PAPER-Cryptography and Information Security

      Vol:
    E103-A No:4
      Page(s):
    686-694

    To increase the number of wireless devices such as mobile or IoT terminals, cryptosystems are essential for secure communications. In this regard, random number generation is crucial because the appropriate function of cryptosystems relies on it to work properly. This paper proposes a true random number generator (TRNG) method capable of working in wireless communication systems. By embedding a TRNG in such systems, no additional analog circuits are required and working conditions can be limited as long as wireless communication systems are functioning properly, making TRNG method cost-effective. We also present some theoretical background and considerations. We next conduct experimental verification, which strongly supports the viability of the proposed method.

  • Mathematical Analysis of Phase Resetting Control Mechanism during Rhythmic Movements

    Kazuki NAKADA  Keiji MIURA  

     
    INVITED PAPER

      Vol:
    E103-A No:2
      Page(s):
    398-406

    Possible functional roles of the phase resetting control during rhythmic movements have been attracting much attention in the field of robotics. The phase resetting control is a control mechanism in which the phase shift of periodic motion is induced depending on the timing of a given perturbation, leading to dynamical stability such as a rapid transition from an unstable state to a stable state in rhythmic movements. A phase response curve (PRC) is used to quantitatively evaluate the phase shift in the phase resetting control. It has been demonstrated that an optimal PRC for bipedal walking becomes bimodal. The PRCs acquired by reinforcement learning in simulated biped walking are qualitatively consistent with measured results obtained from experiments. In this study, we considered how such characteristics are obtained from a mathematical point of view. First, we assumed a symmetric Bonhoeffer-Van der Pol oscillator and phase excitable element known as an active rotator as a model of the central pattern generator for controlling rhythmic movements. Second, we constructed feedback control systems by combining them with manipulators. Next, we numerically computed the PRCs of such systems and compared the resulting PRCs. Furthermore, we approximately calculated analytical solutions of the PRCs. Based on the results, we systematically investigated the parameter dependence of the analytical PRCs. Finally, we investigated the requirements for realizing an optimal PRC for the phase resetting control during rhythmic movements.

  • New Pseudo-Random Number Generator for EPC Gen2

    Hiroshi NOMAGUCHI  Chunhua SU  Atsuko MIYAJI  

     
    PAPER-Cryptographic Techniques

      Pubricized:
    2019/11/14
      Vol:
    E103-D No:2
      Page(s):
    292-298

    RFID enable applications are ubiquitous in our society, especially become more and more important as IoT management rises. Meanwhile, the concern of security and privacy of RFID is also increasing. The pseudorandom number generator is one of the core primitives to implement RFID security. Therefore, it is necessary to design and implement a secure and robust pseudo-random number generator (PRNG) for current RFID tag. In this paper, we study the security of light-weight PRNGs for EPC Gen2 RFID tag which is an EPC Global standard. For this reason, we have analyzed and improved the existing research at IEEE TrustCom 2017 and proposed a model using external random numbers. However, because the previous model uses external random numbers, the speed has a problem depending on the generation speed of external random numbers. In order to solve this problem, we developed a pseudorandom number generator that does not use external random numbers. This model consists of LFSR, NLFSR and SLFSR. Safety is achieved by using nonlinear processing such as multiplication and logical multiplication on the Galois field. The cycle achieves a cycle longer than the key length by effectively combining a plurality of LFSR and the like. We show that our proposal PRNG has good randomness and passed the NIST randomness test. We also shows that it is resistant to identification attacks and GD attacks.

  • Algebraic Group Structure of the Random Number Generator: Theoretical Analysis of NTU Sequence(s)

    Yuta KODERA  Md. Arshad ALI  Takeru MIYAZAKI  Takuya KUSAKA  Yasuyuki NOGAMI  Satoshi UEHARA  Robert H. MORELOS-ZARAGOZA  

     
    PAPER-Sequences

      Vol:
    E102-A No:12
      Page(s):
    1659-1667

    An algebraic group is an essential mathematical structure for current communication systems and information security technologies. Further, as a widely used technology underlying such systems, pseudorandom number generators have become an indispensable part of their construction. This paper focuses on a theoretical analysis for a series of pseudorandom sequences generated by a trace function and the Legendre symbol over an odd characteristic field. As a consequence, the authors give a theoretical proof that ensures a set of subsequences forms a group with a specific binary operation.

  • Detecting Surface Defects of Wind Tubine Blades Using an Alexnet Deep Learning Algorithm Open Access

    Xiao-Yi ZHAO  Chao-Yi DONG  Peng ZHOU  Mei-Jia ZHU  Jing-Wen REN  Xiao-Yan CHEN  

     
    PAPER-Machine Learning

      Vol:
    E102-A No:12
      Page(s):
    1817-1824

    The paper employed an Alexnet, which is a deep learning framework, to automatically diagnose the damages of wind power generator blade surfaces. The original images of wind power generator blade surfaces were captured by machine visions of a 4-rotor UAV (unmanned aerial vehicle). Firstly, an 8-layer Alexnet, totally including 21 functional sub-layers, is constructed and parameterized. Secondly, the Alexnet was trained with 10000 images and then was tested by 6-turn 350 images. Finally, the statistic of network tests shows that the average accuracy of damage diagnosis by Alexnet is about 99.001%. We also trained and tested a traditional BP (Back Propagation) neural network, which have 20-neuron input layer, 5-neuron hidden layer, and 1-neuron output layer, with the same image data. The average accuracy of damage diagnosis of BP neural network is 19.424% lower than that of Alexnet. The point shows that it is feasible to apply the UAV image acquisition and the deep learning classifier to diagnose the damages of wind turbine blades in service automatically.

1-20hit(176hit)