Design and control of noise-induced synchronization patterns

We propose a method for controlling synchronization patterns of limit-cycle oscillators by common noisy inputs, i.e., by utilizing noise-induced synchronization. Various synchronization patterns, including fully synchronized and clustered states, can be realized by using linear filters that generate appropriate common noisy signals from given noise. The optimal linear filter can be determined from the linear phase response property of the oscillators and the power spectrum of the given noise. The validity of the proposed method is confirmed by numerical simulations.Comment: 6 pages, 4 figure

A Lightweight Transmission Parameter Selection Scheme Using Reinforcement Learning for LoRaWAN

The number of IoT devices is predicted to reach 125 billion by 2023. The growth of IoT devices will intensify the collisions between devices, degrading communication performance. Selecting appropriate transmission parameters, such as channel and spreading factor (SF), can effectively reduce the collisions between long-range (LoRa) devices. However, most of the schemes proposed in the current literature are not easy to implement on an IoT device with limited computational complexity and memory. To solve this issue, we propose a lightweight transmission-parameter selection scheme, i.e., a joint channel and SF selection scheme using reinforcement learning for low-power wide area networking (LoRaWAN). In the proposed scheme, appropriate transmission parameters can be selected by simple four arithmetic operations using only Acknowledge (ACK) information. Additionally, we theoretically analyze the computational complexity and memory requirement of our proposed scheme, which verified that our proposed scheme could select transmission parameters with extremely low computational complexity and memory requirement. Moreover, a large number of experiments were implemented on the LoRa devices in the real world to evaluate the effectiveness of our proposed scheme. The experimental results demonstrate the following main phenomena. (1) Compared to other lightweight transmission-parameter selection schemes, collisions between LoRa devices can be efficiently avoided by our proposed scheme in LoRaWAN irrespective of changes in the available channels. (2) The frame success rate (FSR) can be improved by selecting access channels and using SFs as opposed to only selecting access channels. (3) Since interference exists between adjacent channels, FSR and fairness can be improved by increasing the interval of adjacent available channels.Comment: 14 pages, 12 figures, 8 tables. This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

Theory of Acceleration of Decision Making by Correlated Time Sequences

Photonic accelerators have been intensively studied to provide enhanced information processing capability to benefit from the unique attributes of physical processes. Recently, it has been reported that chaotically oscillating ultrafast time series from a laser, called laser chaos, provide the ability to solve multi-armed bandit (MAB) problems or decision-making problems at GHz order. Furthermore, it has been confirmed that the negatively correlated time-domain structure of laser chaos contributes to the acceleration of decision-making. However, the underlying mechanism of why decision-making is accelerated by correlated time series is unknown. In this study, we demonstrate a theoretical model to account for accelerating decision-making by correlated time sequence. We first confirm the effectiveness of the negative autocorrelation inherent in time series for solving two-armed bandit problems using Fourier transform surrogate methods. We propose a theoretical model that concerns the correlated time series subjected to the decision-making system and the internal status of the system therein in a unified manner, inspired by correlated random walks. We demonstrate that the performance derived analytically by the theory agrees well with the numerical simulations, which confirms the validity of the proposed model and leads to optimal system design. The present study paves the way for improving the effectiveness of correlated time series for decision-making, impacting artificial intelligence and other applications

Clinical usefulness of super high-resolution liquid crystal displays using independent sub-pixel driving technology

金沢大学医薬保健研究域保健学系We have developed and reported super-high resolution liquid crystal displays (SHR-LCDs) using a new resolution enhancement technology of the independent sub-pixel driving (ISD) that utilizes three sub-pixels contained in each pixel element. This technology realizes the three-times resolution enhancement of monochrome LCDs. A 15 mega-pixel (MP) SHR-LCD out of a 5MP LCD and a 9MP SHR-LCD out of a 3MP LCD, for example, are realized by this technology, which improves the depiction ability of detailed image shapes such as micro-calcifications of a mammography. Furthermore, the ISD technology brings not only resolution enhancement but also noise reduction effect by the high-frequency data sampling in displaying the clinical images. In this study, we have investigated the clinical efficacy of the SHR-LCDs by means of phantom observation studies and blind observer comparison studies using clinical mammography images performed by radiologists. We used a conventional 5MP LCD for a comparison of a 15MP SHR-LCD and a 9MP SHR-LCD to evaluate their efficacy. From the results of the studies, it was indicated that the SHR-LCDs using the ISD technology had the excellent ability to display the high-resolution digital mammography images. © 2008 Springer-Verlag Berlin Heidelberg

Economical (k,m)-threshold controlled quantum teleportation

We study a (k,m)-threshold controlling scheme for controlled quantum teleportation. A standard polynomial coding over GF(p) with prime p > m-1 needs to distribute a d-dimensional qudit with d >= p to each controller for this purpose. We propose a scheme using m qubits (two-dimensional qudits) for the controllers' portion, following a discussion on the benefit of a quantum control in comparison to a classical control of a quantum teleportation.Comment: 11 pages, 2 figures, v2: minor revision, discussions improved, an equation corrected in procedure (A) of section 4.3, v3: major revision, protocols extended, citations added, v4: minor grammatical revision, v5: minor revision, discussions extende

Reactivity of CA19-9 and CA125 in Histological Subtypes of Epithelial Ovarian Tumors and Ovarian Endometriosis

Previous reports have shown that some ovarian endometrioid adenocarcinomas and ovarian clear cell adenocarcinomas derive from ovarian endometriosis (OE), and that endocervical-like mucinous borderline ovarian tumors are associated with OE. We examined the relationship between the staging and histological subtypes of OE or epithelial ovarian tumors (EOT) and the serum levels of carbohydrate antigen 19-9 (CA19-9) and carbohydrate antigen 125 (CA125) to evaluate the potential of these markers for preoperative diagnosis. First, we analyzed the preoperative serum levels of CA19-9 and CA125 in 195 patients who were histopathologically diagnosed with OE or EOT. We then performed a case-control study in which 308 women were enrolled, the 195 women described above and 113 healthy women as control subjects. Serum CA19-9 and CA125 levels were found to be useful in differentiating between OE and serous adenocarcinoma, but not between OE and other EOT. Moreover, serum CA19-9 levels were useful for preoperative assessment between OE and stage I mucinous borderline ovarian tumors, with or without the interstitial infiltration. In addition, considering that the serum CA19-9 levels in stage I mucinous borderline ovarian tumors were elevated via the interstitial infiltration of leukocytes and that precancerous lesions are associated with a cancerous glycosylation disorder in the process of inflammatory carcinogenesis, the CA19-9 level may be considered a suitable biomarker for estimating drug susceptibility

Noise reduction effect in super-high resolution LCDs using independent sub-pixel driving technology

We have developed and reported a super-high resolution liquid crystal display (SHR-LCD) using a new resolution enhancement technology of the independent sub-pixel driving (ISD) that utilizes three sub-pixels in each pixel element. This technology realizes the three-times resolution enhancement of monochrome LCDs, and improves the depiction ability of detailed shape such as micro-calcifications of a mammography and bone structures. Furthermore, the ISD technology brings not only resolution enhancement but also noise reduction effect by the high-resolution data sampling in displaying the clinical images. In this study, we examined the efficacy of the newly developed LCDs from the noise power spectrum measurement (NPS), the perceptual comparison of the phantom images and the clinical images. A 15 mega-pixel (MP)SHR-LCD out of a 5MP LCD and a 6MP SHR-LCD out of a 2MP LCD were used for the measurement and the evaluation. In the NPS measurements, the noise of all the SHR-LCDs was improved obviously. The improvement degree of the NPS varied according to the sub-sampling ratio of the data sampling implemented during the image displaying, and the 6MP LCD showed higher improvement. In the perceptual evaluation of the quality-control phantom images and the low-contrast images of the micro-calcifications of the mammography, all the SHR-LCDs provided higher performance than the conventional LCDs. These results proved that the SHR-LCDs using the ISD technology had the excellent ability to display the high-resolution clinical images

Development of a new resolution enhancement technology for medical liquid crystal displays

金沢大学大学院医学系研究科量子医療技術学A new resolution enhancement technology that used independent sub-pixel driving method was developed for medical monochrome liquid crystal displays (LCDs). Each pixel of monochrome LCDs, which employ color liquid crystal panels with color filters removed, consists of three sub-pixels. In the new LCD system implemented with this technology, sub-pixel intensities were modulated according to detailed image information, and consequently resolution was enhanced three times. In addition, combined with adequate resolution improvement by image data processing, horizontal and vertical resolution properties were balanced. Thus the new technology realized 9 mega-pixels (MP) ultra-high resolution out of 3MP LCD. Physical measurements and perceptual evaluations proved that the achieved 9MP (through our new technology) was appropriate and efficient to depict finer anatomical structures such as micro calcifications in mammography