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  • Designing a Framework for Data Quality Validation of Meteorological Data System Open Access

    Wen-Lung TSAI  Yung-Chun CHAN  

     
    PAPER

      Pubricized:
    2019/01/22
      Vol:
    E102-D No:4
      Page(s):
    800-809

    In the current era of data science, data quality has a significant and critical impact on business operations. This is no different for the meteorological data encountered in the field of meteorology. However, the conventional methods of meteorological data quality control mainly focus on error detection and null-value detection; that is, they only consider the results of the data output but ignore the quality problems that may also arise in the workflow. To rectify this issue, this paper proposes the Total Meteorological Data Quality (TMDQ) framework based on the Total Quality Management (TQM) perspective, especially considering the systematic nature of data warehousing and process focus needs. In practical applications, this paper uses the proposed framework as the basis for the development of a system to help meteorological observers improve and maintain the quality of meteorological data in a timely and efficient manner. To verify the feasibility of the proposed framework and demonstrate its capabilities and usage, it was implemented in the Tamsui Meteorological Observatory (TMO) in Taiwan. The four quality dimension indicators established through the proposed framework will help meteorological observers grasp the various characteristics of meteorological data from different aspects. The application and research limitations of the proposed framework are discussed and possible directions for future research are presented.

  • Design Optimization of Radar Absorbent Material for Broadband and Continuous Oblique Incidence Characteristics

    Yuka ISHII  Naobumi MICHISHITA  Hisashi MORISHITA  Yuki SATO  Kazuhiro IZUI  Shinji NISHIWAKI  

     
    PAPER-Electromagnetic Compatibility(EMC)

      Pubricized:
    2018/08/21
      Vol:
    E102-B No:2
      Page(s):
    216-223

    Radar-absorbent materials (RAM) with various characteristics, such as broadband, oblique-incidence, and polarization characteristics, have been developed according to applications in recent years. This paper presents the optimized design method of two flat layers RAM with both broadband and oblique-incidence characteristics for the required RAM performance. The oblique-incidence characteristics mean that the RAM is possible to absorb radio waves continuously up to the maximum incidence angle. The index of the wave-absorption amount is 20dB, corresponding to an absorption rate of 99%. Because determination of the electrical material constant of each layer is the most important task with respect to the received frequency and the incidence angle, we optimized the values by using Non-dominated sorting genetic algorithm-II (NSGA-II). Two types of flat-layer RAM composed of dielectric and magnetic materials were designed and their characteristics were evaluated. Consequently, it was confirmed that oblique-incidence characteristics were better for the RAM composed of dielectric materials. The dielectric RAM achieved an incidence angle of up to 60° with broadband characteristics and a relative bandwidth of 77.01% at the transverse-magnetic (TM) wave incidence. In addition, the magnetic RAM could lower the minimum frequency of the system more than the dielectric RAM. The minimum frequency of the magnetic RAM was 1.38GHz with a relative bandwidth of 174.18% at TM-wave incidence and an incidence angle of 45°. We confirmed that it is possible to design RAM with broadband characteristics and continuous oblique-incidence characteristics by using the proposed method.

  • Fabrication of the Flexible Dual-Gate OFET Based Organic Pressure Sensor

    Tatsuya ISHIKAWA  Heisuke SAKAI  Hideyuki MURATA  

     
    BRIEF PAPER

      Vol:
    E102-C No:2
      Page(s):
    188-191

    We have developed the flexible dual-gate OFET based pressure sensor using a thin polyethylene naphthalate (PEN, 25 µm) film as a substrate. The performance was equivalent to that fabricated on the glass substrate, and it could also be used on the curved surface. Drain current in the flexible pressure sensor was increased according to the pressure load without application of gate voltage. The magnitude of the change in drain current with respect to pressure application was about 2.5 times larger than that for the device on the glass substrate.

  • Probabilistic Analysis of Differential Fault Attack on MIBS

    Yang GAO  Yong-juan WANG  Qing-jun YUAN  Tao WANG  Xiang-bin WANG  

     
    PAPER-Information Network

      Pubricized:
    2018/11/16
      Vol:
    E102-D No:2
      Page(s):
    299-306

    We propose a new method of differential fault attack, which is based on the nibble-group differential diffusion property of the lightweight block cipher MIBS. On the basis of the statistical regularity of differential distribution of the S-box, we establish a statistical model and then analyze the relationship between the number of faults injections, the probability of attack success, and key recovering bits. Theoretically, time complexity of recovering the main key reduces to 22 when injecting 3 groups of faults (12 nibbles in total) in 30,31 and 32 rounds, which is the optimal condition. Furthermore, we calculate the expectation of the number of fault injection groups needed to recover 62 bits in main key, which is 3.87. Finally, experimental data verifies the correctness of the theoretical model.

  • A Universal Two-Dimensional Source Coding by Means of Subblock Enumeration Open Access

    Takahiro OTA  Hiroyoshi MORITA  Akiko MANADA  

     
    PAPER-Information Theory

      Vol:
    E102-A No:2
      Page(s):
    440-449

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

  • Electromagnetic Absorber Made by Natural Rubber Open Access

    Kiadtisak SALAYONG  Titipong LERTWIRIYAPRAPA  Kittisak PHAEBUA  Prayoot AKKARAEKTHALIN  Hsi-Tseng CHOU  

     
    INVITED PAPER-Electromagnetic Compatibility(EMC)

      Pubricized:
    2018/08/21
      Vol:
    E102-B No:2
      Page(s):
    189-196

    This paper proposes fabrication process of a pyramidal electromagnetic (EM) absorber made by natural rubber. The advantage of this research is to generate value-added latex from Thai rubber and to reduce number of chemical absorber by using natural rubber based absorber. The proposed absorber in the research is mainly made from latex with carbon black filler. The proposed absorber is in the form of rubber foam which provides suitable characteristics to serve as an EM absorber. The results of this research are chemical formulas for fabrication of pyramidal rubber foam with carbon black filler. The fabrication cost is very low when compared to an available commercial absorber. The electrical properties of the proposed EM absorber are measured. Also the reflectivity is measured and compared well with a commercial EM absorber.

  • Enzymatic Biofuel Cell Using Graphene Electrodes with Improved Interfacial Electron Transfer

    Kenta KUROISHI  Toshinari DOI  Kazuki HOSHI  Kazuo MURAMATSU  Yasushiro NISHIOKA  Satomitsu IMAI  

     
    BRIEF PAPER

      Vol:
    E102-C No:2
      Page(s):
    159-163

    In this study, we optimized the reforming of bilirubin oxidase (BOD) using graphene-coated carbon fiber woven fabric (GCFC) as an electrode, and The performance of the cathode in which synthesized 1-pyrene butyric acid N-hydroxysuccinimide ester (PBSE) and 2,5-dimethyl-1-phenyl-1-H-pyrrole-3-carbaldehyde (DPPC) were added, was evaluated. In addition, the prototype evaluation of the atmospheric-exposure-type ascorbic acid enzyme biofuel cell (AAEBFC) using the improved GCFC cathode was performed. The area of both the anode and cathode electrodes was 5mm × 5mm. No modification was performed to the anode, and only the cathode was coated with the enzyme BOD. In the work, for the AAEBFC using the BOD-modified cathode, an output of 238.5µW/cm2 was obtained at 0.245V. Further, in the AAEBFC using the DPPC-PBSE-BOD-modified cathode, an output of 338.8µW/cm2 was obtained at 0.292V. The output in this work was improved by approximately 1.4 times by the additives.

  • Patterning of OLED Glass Substrate for Improving Light Outcoupling Efficiency

    Savanna LLOYD  Tatsuya TANIGAWA  Heisuke SAKAI  Hideyuki MURATA  

     
    BRIEF PAPER

      Vol:
    E102-C No:2
      Page(s):
    180-183

    In this work, we have successfully patterned OLED glass substrates with a novel Yb-doped femtosecond laser. Such patterns can simultaneously increase the outcoupling efficiency up to 24.4%, as a result of reducing substrate waveguided light by scattering at the substrate/air interface and reduce the viewing angle dependence of the electroluminescent spectra.

  • In situ Observation of Capturing BTB Molecules from Aqueous Solutions with Hydrophobic DNA Nano-Film

    Naoki MATSUDA  Hirotaka OKABE  Ayako OMURA  Miki NAKANO  Koji MIYAKE  Toshihiko NAGAMURA  Hideki KAWAI  

     
    BRIEF PAPER

      Vol:
    E102-C No:2
      Page(s):
    203-206

    Hydrophobic DNA (H-DNA) nano-film was formed on a thin glass plate of 50μm thick working as a slab optical waveguide. Bromothymol blue (BTB) molecules were immobilized from aqueous solution with direct contacting to the H-DNA nano-film for 20 minutes. From changes in absorption spectra observed with slab optical wave guide (SOWG) during automated solution exchange (SE) processes for 100 times, it was found that about 95% of bromothymol blue (BTB) molecules was immobilized in the H-DNA nano-film with keeping their functionality of color change responsible to pH change in the solution.

  • A Novel Class of Structured Zero-Correlation Zone Sequence Sets

    Takafumi HAYASHI  Takao MAEDA  Anh T. PHAM  Shinya MATSUFUJI  

     
    PAPER-Sequence

      Vol:
    E101-A No:12
      Page(s):
    2171-2183

    The present paper introduces a novel type of structured ternary sequences having a zero-correlation zone (zcz) for both periodic and aperiodic correlation functions. The cross-correlation function and the side lobe of the auto-correlation function of the proposed sequence set are zero for phase shifts within the zcz. The proposed zcz sequence set can be generated from an arbitrary pair of an Hadamard matrix of order lh and a binary/ternary perfect sequence of length lp. The sequence set of order 0 is identical to the r-th row of the Hadamard matrix. For m ≥ 0, the sequence set of order (m+1) is constructed from the sequence set of order m by sequence concatenation and interleaving. The sequence set has lp subsets of size 2lh. The periodic correlation function and the aperiodic correlation function of the proposed sequence set have a zcz from -(2m+1-1) to 2m+1-1. The periodic correlation function and the aperiodic correlation function of the sequences of the i-th subset and k-th subset have a zcz from -2m+2-(lh+1)((j-k) mod lp) to -2m+2-(lh+1)((j-k) mod lp). The proposed sequence is suitable for a heterogeneous wireless network, which is one of the candidates for the fifth-generation mobile networks.

  • Towards Finding Code Snippets on a Question and Answer Website Causing Mobile App Vulnerabilities

    Hiroki NAKANO  Fumihiro KANEI  Yuta TAKATA  Mitsuaki AKIYAMA  Katsunari YOSHIOKA  

     
    PAPER-Mobile Application and Web Security

      Pubricized:
    2018/08/22
      Vol:
    E101-D No:11
      Page(s):
    2576-2583

    Android app developers sometimes copy code snippets posted on a question-and-answer (Q&A) website and use them in their apps. However, if a code snippet has vulnerabilities, Android apps containing the vulnerable snippet could also have the same vulnerabilities. Despite this, the effect of such vulnerable snippets on the Android apps has not been investigated in depth. In this paper, we investigate the correspondence between the vulnerable code snippets and vulnerable apps. we collect code snippets from a Q&A website, extract possibly vulnerable snippets, and calculate similarity between those snippets and bytecode on vulnerable apps. Our experimental results show that 15.8% of all evaluated apps that have SSL implementation vulnerabilities (Improper host name verification), 31.7% that have SSL certificate verification vulnerabilities, and 3.8% that have WEBVIEW remote code execution vulnerabilities contain possibly vulnerable code snippets from Stack Overflow. In the worst case, a single problematic snippet has caused 4,844 apps to contain a vulnerability, accounting for 31.2% of all collected apps with that vulnerability.

  • Formation of Polymer Wall Structure on Plastic Substrate by Transfer Method of Fluororesin for Flexible Liquid Crystal Displays

    Seiya KAWAMORITA  Yosei SHIBATA  Takahiro ISHINABE  Hideo FUJIKAKE  

     
    BRIEF PAPER

      Vol:
    E101-C No:11
      Page(s):
    888-891

    In this paper, we examined the transfer method of fluororesin as the novel formation method of polymer wall in order to realize the lattice-shaped polymer walls without patterned light irradiation using photomask. We clarified that the transfer method was effective for formation of polymer wall structure on flexible substrate.

  • Identifying Evasive Code in Malicious Websites by Analyzing Redirection Differences

    Yuta TAKATA  Mitsuaki AKIYAMA  Takeshi YAGI  Takeo HARIU  Kazuhiko OHKUBO  Shigeki GOTO  

     
    PAPER-Mobile Application and Web Security

      Pubricized:
    2018/08/22
      Vol:
    E101-D No:11
      Page(s):
    2600-2611

    Security researchers/vendors detect malicious websites based on several website features extracted by honeyclient analysis. However, web-based attacks continue to be more sophisticated along with the development of countermeasure techniques. Attackers detect the honeyclient and evade analysis using sophisticated JavaScript code. The evasive code indirectly identifies vulnerable clients by abusing the differences among JavaScript implementations. Attackers deliver malware only to targeted clients on the basis of the evasion results while avoiding honeyclient analysis. Therefore, we are faced with a problem in that honeyclients cannot analyze malicious websites. Nevertheless, we can observe the evasion nature, i.e., the results in accessing malicious websites by using targeted clients are different from those by using honeyclients. In this paper, we propose a method of extracting evasive code by leveraging the above differences to investigate current evasion techniques. Our method analyzes HTTP transactions of the same website obtained using two types of clients, a real browser as a targeted client and a browser emulator as a honeyclient. As a result of evaluating our method with 8,467 JavaScript samples executed in 20,272 malicious websites, we discovered previously unknown evasion techniques that abuse the differences among JavaScript implementations. These findings will contribute to improving the analysis capabilities of conventional honeyclients.

  • Efficient Reusable Collections

    Davud MOHAMMADPUR  Ali MAHJUR  

     
    PAPER-Fundamentals of Information Systems

      Pubricized:
    2018/08/20
      Vol:
    E101-D No:11
      Page(s):
    2710-2719

    Efficiency and flexibility of collections have a significant impact on the overall performance of applications. The current approaches to implement collections have two main drawbacks: (i) they limit the efficiency of collections and (ii) they have not adequate support for collection composition. So, when the efficiency and flexibility of collections is important, the programmer needs to implement them himself, which leads to the loss of reusability. This article presents neoCollection, a novel approach to encapsulate collections. neoCollection has several distinguishing features: (i) it can be applied on data elements efficiently and flexibly (ii) composition of collections can be made efficiently and flexibly, a feature that does not exist in the current approaches. In order to demonstrate its effectiveness, neoCollection is implemented as an extension to Java and C++.

  • Distributed Energy Efficient Resource Allocation for OFDMA Smallcell Networks

    Guodong ZHANG  Shibing ZHANG  Zhihua BAO  

     
    PAPER-Terrestrial Wireless Communication/Broadcasting Technologies

      Pubricized:
    2018/04/27
      Vol:
    E101-B No:11
      Page(s):
    2362-2370

    Smallcells have recently emerged as a potential approach for local area deployments that can satisfy high data rate requirements, reduce energy consumption and enhance network coverage. In this paper, we work on maximizing the weighted sum energy efficiency (WS-EE) for densely deployed smallcell networks. Due to the combinatorial and the general fractional program nature of the resource allocation problem, WS-EE maximization is non-convex and the optimal joint resource blocks (RBs) and power allocation is NP-hard. To solve this complex problem, we propose to decompose the primal problem into two subproblems (referred as RBs allocation and power control) and solve the subproblems sequentially. For the RBs allocation subproblem given any feasible network power profile, the optimal solution can be solved by maximizing throughput locally. For the power control subproblem, we propose to solve it locally based on a new defined pricing factor. Then, a distributed power control algorithm with guaranteed convergence is designed to achieve a Karush-Kuhn-Tucker (KKT) point of the primal problem. Simulation results verify the performance improvement of our proposed resource allocation scheme in terms of WS-EE. Besides, the performance evaluation shows the tradeoff between the WS-EE and the sum rate of the smallcell networks.

  • Absorber Integrated Planar Slot Array Antenna for Suppression of Multiple Reflection in 120-GHz-Band Close-Proximity Wireless System

    Akihiko HIRATA  Jiro HIROKAWA  

     
    PAPER

      Vol:
    E101-C No:10
      Page(s):
    791-800

    This paper proposes the absorber integrated planar array antenna for a 120-GHz-band close proximity wireless system. It consists of split-ring resonators (SRRs) patterned on a quartz substrate and a plate-laminated-waveguide planar slot array antenna. Precise alignment and multiple reflection between Tx-Rx antenna become severe problem as the carrier frequency increases, such as >100GHz. The absorber integrated planar slot array antenna solves these problems. We designed a SRR unit cell that acts as a millimeter-wave (MMW) absorber, and the simulated S11 of the SRR absorber at 125GHz is -37dB. The use of the SRR absorber on the planar slot antenna suppresses the multiple reflection between Tx and Rx antennas, however the transmission loss between Tx and Rx antennas increases. We changed the conductivity and cell size of 2×3 element SRR unit cells directly above the waveguide slots in order to make them act as an SRR director, and the use of the SRR director improved the transmission loss by 2.7dB. We simulated the transmission characteristics of a close-proximity wireless system using the SRR absorber integrated planar slot antennas. The simulated fluctuation of S21 in the 120-130GHz band is below 2.6dB, and the delayed waves that come from the multiple reflection between Tx and Rx antennas were suppressed.

  • Low Bit-Rate Compression Image Restoration through Subspace Joint Regression Learning

    Zongliang GAN  

     
    LETTER-Image Processing and Video Processing

      Pubricized:
    2018/06/28
      Vol:
    E101-D No:10
      Page(s):
    2539-2542

    In this letter, an effective low bit-rate image restoration method is proposed, in which image denoising and subspace regression learning are combined. The proposed framework has two parts: image main structure estimation by classical NLM denoising and texture component prediction by subspace joint regression learning. The local regression function are learned from denoised patch to original patch in each subspace, where the corresponding compression image patches are employed to generate anchoring points by the dictionary learning approach. Moreover, we extent Extreme Support Vector Regression (ESVR) as multi-variable nonlinear regression to get more robustness results. Experimental results demonstrate the proposed method achieves favorable performance compared with other leading methods.

  • Winding Ratio Design of Transformer in Equivalent Circuit of Circular Patch Array Absorber

    Ryosuke SUGA  Tomohiko NAKAMURA  Daisuke KITAHARA  Kiyomichi ARAKI  Osamu HASHIMOTO  

     
    BRIEF PAPER

      Vol:
    E101-C No:8
      Page(s):
    651-654

    An equivalent circuit of a circular patch array absorber has been proposed, however the method to identify a winding ratio of a transformer in its circuit have never been reported. In this paper, it is indicated that the ratio is proportionate to the area ratio between patch and unit cell of the absorber, and the design method of the winding ratio is proposed. The winding ratio derived by the proposed method is agreed well with that by using electromagnetic simulator within 3% error. Moreover, the operating frequency and 15 dB bandwidth of the fabricated absorber designed by proposed method are agreed with those derived by the circuit simulation within 0.4% and 0.1% errors. Thus the validity of the proposed method is verified.

  • Heteroepitaxial Growth of GaAs/Ge Buffer Layer on Si for Metamorphic InGaAs Lasers Open Access

    Ryo NAKAO  Masakazu ARAI  Takaaki KAKITSUKA  Shinji MATSUO  

     
    INVITED PAPER

      Vol:
    E101-C No:7
      Page(s):
    537-544

    We demonstrate heteroepitaxial growth of GaAs/Ge buffer layers for fabricating 1.3-µm range metamorphic InGaAs-based multiple quantum well (MQW) lasers in which the Ge buffer layer is grown using a metal-organic Ge precursor, iso-butyl germane, in a conventional metal-organic vapor phase epitaxy reactor. This enables us to grow Ge and GaAs buffer layers in the same reactor seamlessly. Transmission electron microscopy and X-ray diffraction analyses indicate that dislocations are well confined at the Ge/Si interface. Furthermore, thermal-cycle annealing significantly improves crystalline quality at the GaAs/Ge interface, resulting in higher photoluminescence intensity from the MQWs on the buffer layers.

  • A Subspace Newton-Type Method for Approximating Transversely Repelling Chaotic Saddles

    Hidetaka ITO  Hiroomi HIKAWA  Yutaka MAEDA  

     
    LETTER-Nonlinear Problems

      Vol:
    E101-A No:7
      Page(s):
    1127-1131

    This letter proposes a numerical method for approximating the location of and dynamics on a class of chaotic saddles. In contrast to the conventional strategy of maximizing the escape time, our proposal is to impose a zero-expansion condition along transversely repelling directions of chaotic saddles. This strategy exploits the existence of skeleton-forming unstable periodic orbits embedded in chaotic saddles, and thus can be conveniently implemented as a variant of subspace Newton-type methods. The algorithm is examined through an illustrative and another standard example.

81-100hit(927hit)

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