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Taro Takemoto - One of the best experts on this subject based on the ideXlab platform.

  • hbox he _ 11 Mode Effect on direct wave in single hole borehole radar
    IEEE Transactions on Geoscience and Remote Sensing, 2011
    Co-Authors: Satoshi Ebihara, Akihito Sasakura, Taro Takemoto
    Abstract:

    In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles. According to our calculation, at high frequencies above 200 MHz, guided waves, which are caused by the poles, play a vital role in the direct wave. We found that the most important pole is the HE11 Mode one, which is excited only when the antenna is eccentered in the borehole. We show that this causes artificial noise in the moving average subtraction, which is a common signal processing method used to remove the direct wave. In a laboratory experiment with a ground plane, we confirmed the excitation of the guided waves when the antenna was eccentered. In field experiments in granite, we conducted a special experiment, in which the location and rotation of the radar sonde were controlled mechanically. We found the excitation of the HE11 Mode at high frequencies when the sonde was noncentered by 1.7 cm in a borehole. These Effects are also predicted in a theoretical analysis.

  • $\hbox{HE}_{11}$ Mode Effect on Direct Wave in Single-Hole Borehole Radar
    IEEE Transactions on Geoscience and Remote Sensing, 2011
    Co-Authors: Satoshi Ebihara, Akihito Sasakura, Taro Takemoto
    Abstract:

    In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles. According to our calculation, at high frequencies above 200 MHz, guided waves, which are caused by the poles, play a vital role in the direct wave. We found that the most important pole is the HE11 Mode one, which is excited only when the antenna is eccentered in the borehole. We show that this causes artificial noise in the moving average subtraction, which is a common signal processing method used to remove the direct wave. In a laboratory experiment with a ground plane, we confirmed the excitation of the guided waves when the antenna was eccentered. In field experiments in granite, we conducted a special experiment, in which the location and rotation of the radar sonde were controlled mechanically. We found the excitation of the HE11 Mode at high frequencies when the sonde was noncentered by 1.7 cm in a borehole. These Effects are also predicted in a theoretical analysis.

Satoshi Ebihara - One of the best experts on this subject based on the ideXlab platform.

  • hbox he _ 11 Mode Effect on direct wave in single hole borehole radar
    IEEE Transactions on Geoscience and Remote Sensing, 2011
    Co-Authors: Satoshi Ebihara, Akihito Sasakura, Taro Takemoto
    Abstract:

    In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles. According to our calculation, at high frequencies above 200 MHz, guided waves, which are caused by the poles, play a vital role in the direct wave. We found that the most important pole is the HE11 Mode one, which is excited only when the antenna is eccentered in the borehole. We show that this causes artificial noise in the moving average subtraction, which is a common signal processing method used to remove the direct wave. In a laboratory experiment with a ground plane, we confirmed the excitation of the guided waves when the antenna was eccentered. In field experiments in granite, we conducted a special experiment, in which the location and rotation of the radar sonde were controlled mechanically. We found the excitation of the HE11 Mode at high frequencies when the sonde was noncentered by 1.7 cm in a borehole. These Effects are also predicted in a theoretical analysis.

  • $\hbox{HE}_{11}$ Mode Effect on Direct Wave in Single-Hole Borehole Radar
    IEEE Transactions on Geoscience and Remote Sensing, 2011
    Co-Authors: Satoshi Ebihara, Akihito Sasakura, Taro Takemoto
    Abstract:

    In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles. According to our calculation, at high frequencies above 200 MHz, guided waves, which are caused by the poles, play a vital role in the direct wave. We found that the most important pole is the HE11 Mode one, which is excited only when the antenna is eccentered in the borehole. We show that this causes artificial noise in the moving average subtraction, which is a common signal processing method used to remove the direct wave. In a laboratory experiment with a ground plane, we confirmed the excitation of the guided waves when the antenna was eccentered. In field experiments in granite, we conducted a special experiment, in which the location and rotation of the radar sonde were controlled mechanically. We found the excitation of the HE11 Mode at high frequencies when the sonde was noncentered by 1.7 cm in a borehole. These Effects are also predicted in a theoretical analysis.

Akihito Sasakura - One of the best experts on this subject based on the ideXlab platform.

  • hbox he _ 11 Mode Effect on direct wave in single hole borehole radar
    IEEE Transactions on Geoscience and Remote Sensing, 2011
    Co-Authors: Satoshi Ebihara, Akihito Sasakura, Taro Takemoto
    Abstract:

    In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles. According to our calculation, at high frequencies above 200 MHz, guided waves, which are caused by the poles, play a vital role in the direct wave. We found that the most important pole is the HE11 Mode one, which is excited only when the antenna is eccentered in the borehole. We show that this causes artificial noise in the moving average subtraction, which is a common signal processing method used to remove the direct wave. In a laboratory experiment with a ground plane, we confirmed the excitation of the guided waves when the antenna was eccentered. In field experiments in granite, we conducted a special experiment, in which the location and rotation of the radar sonde were controlled mechanically. We found the excitation of the HE11 Mode at high frequencies when the sonde was noncentered by 1.7 cm in a borehole. These Effects are also predicted in a theoretical analysis.

  • $\hbox{HE}_{11}$ Mode Effect on Direct Wave in Single-Hole Borehole Radar
    IEEE Transactions on Geoscience and Remote Sensing, 2011
    Co-Authors: Satoshi Ebihara, Akihito Sasakura, Taro Takemoto
    Abstract:

    In this paper, we investigate the influence of radar sonde eccentricity on a direct wave between a transmitting and a receiving antenna in a single-hole borehole radar measurement. We analyze the direct wave using an analytical method with the approximated solution of branch cut integrals and that of residues of poles. According to our calculation, at high frequencies above 200 MHz, guided waves, which are caused by the poles, play a vital role in the direct wave. We found that the most important pole is the HE11 Mode one, which is excited only when the antenna is eccentered in the borehole. We show that this causes artificial noise in the moving average subtraction, which is a common signal processing method used to remove the direct wave. In a laboratory experiment with a ground plane, we confirmed the excitation of the guided waves when the antenna was eccentered. In field experiments in granite, we conducted a special experiment, in which the location and rotation of the radar sonde were controlled mechanically. We found the excitation of the HE11 Mode at high frequencies when the sonde was noncentered by 1.7 cm in a borehole. These Effects are also predicted in a theoretical analysis.

Pradeep Kumar - One of the best experts on this subject based on the ideXlab platform.

  • systematic failure Mode Effect analysis fmea using fuzzy linguistic Modelling
    International Journal of Quality & Reliability Management, 2005
    Co-Authors: Rajiv Kumar Sharma, Dinesh Kumar, Pradeep Kumar
    Abstract:

    Purpose – To permit the system safety and reliability analysts to evaluate the criticality or risk associated with item failure Modes.Design/methodology/approach – The factors considered in traditional failure Mode and Effect analysis (FMEA) for risk assessment are frequency of occurrence (Sf), severity (S) and detectability (Sd) of an item failure Mode. Because of the subjective and qualitative nature of the information and to make the analysis more consistent and logical, an approach using fuzzy logic is proposed. In the proposed approach, these parameters are represented as members of a fuzzy set fuzzified by using appropriate membership functions and are evaluated in fuzzy inference engine, which makes use of well‐defined rule base and fuzzy logic operations to determine the criticality/riskiness level of the failure. The fuzzy conclusion is then defuzzified to get risk priority number. The higher the value of RPN, the greater will be the risk and lower the value of RPN, and the lesser will be the ris...

  • Systematic failure Mode Effect analysis (FMEA) using fuzzy linguistic Modelling
    International Journal of Quality and Reliability Management, 2005
    Co-Authors: Rajiv Kumar Sharma, Dinesh Kumar, Pradeep Kumar
    Abstract:

    Purpose - To permit the system safety and reliability analysts to evaluate the criticality or risk associated with item failure Modes. Design/methodology/approach - The factors considered in traditional failure Mode and Effect analysis (FMEA) for risk assessment are frequency of occurrence (S f ), severity (S) and detectability (S d ) of an item failure Mode. Because of the subjective and qualitative nature of the information and to make the analysis more consistent and logical, an approach using fuzzy logic is proposed. In the proposed approach, these parameters are represented as members of a fuzzy set fuzzified by using appropriate membership functions and are evaluated in fuzzy inference engine, which makes use of well-defined rule base and fuzzy logic operations to determine the criticality/riskiness level of the failure. The fuzzy conclusion is then defuzzified to get risk priority number. The higher the value of RPN, the greater will be the risk and lower the value of RPN, and the lesser will be the risk. The fuzzy linguistic assessment Model was developed using toolbox platform of MATLAB 6.5 R.13. Findings - The applicability of the proposed approach is investigated with the help of an illustrative case study from the paper industry. Fuzzy risk assessment is carried out for prioritizing failure causes of the hydraulic system, a primary element of the feeding system. The results provide an alternate ranking to that obtained by the traditional method. It is concluded from the study that the fuzzy logic-based approach not only resolves the limitations associated with traditional methodology for RPN evaluation but also permits the experts to combine probability of occurrence (S f ), severity (S) and detectability (S d ) of failure Modes in a more flexible and realistic manner by using their judgement, experience and expertise. Originality/value - The paper integrates the use of fuzzy logic and expert database with FMEA and may prove helpful to system safety and reliability analysts while conducting failure Mode and Effect analysis to prioritize failures for taking corrective or remedial actions. © Emerald Group Publishing Limited.

Rajiv Kumar Sharma - One of the best experts on this subject based on the ideXlab platform.

  • systematic failure Mode Effect analysis fmea using fuzzy linguistic Modelling
    International Journal of Quality & Reliability Management, 2005
    Co-Authors: Rajiv Kumar Sharma, Dinesh Kumar, Pradeep Kumar
    Abstract:

    Purpose – To permit the system safety and reliability analysts to evaluate the criticality or risk associated with item failure Modes.Design/methodology/approach – The factors considered in traditional failure Mode and Effect analysis (FMEA) for risk assessment are frequency of occurrence (Sf), severity (S) and detectability (Sd) of an item failure Mode. Because of the subjective and qualitative nature of the information and to make the analysis more consistent and logical, an approach using fuzzy logic is proposed. In the proposed approach, these parameters are represented as members of a fuzzy set fuzzified by using appropriate membership functions and are evaluated in fuzzy inference engine, which makes use of well‐defined rule base and fuzzy logic operations to determine the criticality/riskiness level of the failure. The fuzzy conclusion is then defuzzified to get risk priority number. The higher the value of RPN, the greater will be the risk and lower the value of RPN, and the lesser will be the ris...

  • Systematic failure Mode Effect analysis (FMEA) using fuzzy linguistic Modelling
    International Journal of Quality and Reliability Management, 2005
    Co-Authors: Rajiv Kumar Sharma, Dinesh Kumar, Pradeep Kumar
    Abstract:

    Purpose - To permit the system safety and reliability analysts to evaluate the criticality or risk associated with item failure Modes. Design/methodology/approach - The factors considered in traditional failure Mode and Effect analysis (FMEA) for risk assessment are frequency of occurrence (S f ), severity (S) and detectability (S d ) of an item failure Mode. Because of the subjective and qualitative nature of the information and to make the analysis more consistent and logical, an approach using fuzzy logic is proposed. In the proposed approach, these parameters are represented as members of a fuzzy set fuzzified by using appropriate membership functions and are evaluated in fuzzy inference engine, which makes use of well-defined rule base and fuzzy logic operations to determine the criticality/riskiness level of the failure. The fuzzy conclusion is then defuzzified to get risk priority number. The higher the value of RPN, the greater will be the risk and lower the value of RPN, and the lesser will be the risk. The fuzzy linguistic assessment Model was developed using toolbox platform of MATLAB 6.5 R.13. Findings - The applicability of the proposed approach is investigated with the help of an illustrative case study from the paper industry. Fuzzy risk assessment is carried out for prioritizing failure causes of the hydraulic system, a primary element of the feeding system. The results provide an alternate ranking to that obtained by the traditional method. It is concluded from the study that the fuzzy logic-based approach not only resolves the limitations associated with traditional methodology for RPN evaluation but also permits the experts to combine probability of occurrence (S f ), severity (S) and detectability (S d ) of failure Modes in a more flexible and realistic manner by using their judgement, experience and expertise. Originality/value - The paper integrates the use of fuzzy logic and expert database with FMEA and may prove helpful to system safety and reliability analysts while conducting failure Mode and Effect analysis to prioritize failures for taking corrective or remedial actions. © Emerald Group Publishing Limited.