A Wavelet Band-Limiting Filter Approach for Fault Detection in Dynamic Systems

This paper presents a wavelet-based analytical redundancy method for the detection of faults in dynamic systems. In the proposed approach, consistency checks are carried out after band-limiting the signals under consideration to specific frequency ranges. For this purpose, the discrete wavelet transform is used to establish the frequency bands of analysis and a finite impulse response filter is employed to check the dynamic consistency of the data within each band. The filter weights can be adjusted by a simple parametric identification procedure on the basis of data acquired under normal operating conditions. The proposed method is illustrated by using experimental fault data from an analog computer, which was adjusted to emulate the dynamic response of a servomechanism, as well as simulated data representing a sensor fault scenario in the operation of a Boeing 747 aircraft. For comparison, a standard Luenberger observer fault detection scheme is also employed. The results show that the wavelet method compares favorably with the observer-based scheme in terms of sensitivity to the fault effect, false alarms, and nondetected faults.     

Clinical and laboratory findings associated with the severity of community-acquired pneumonia

To clarify the clinical features of severe community-acquired pneumonia, we retrospectively studied 121 patients treated at our hospital. We divided the patients into three groups, based on the severity, of their disease. Patients were put in the "mild" group (n = 56) if they recovered after treatment with antimicrobial agents only, they were put in the "moderate" group (n = 34) if the required oxygen therapy and recovered, and they were put in the "severe" group (n = 31) if they required mechanical ventilation. Age and underlying disease were recorded, as well as signs, symptoms, and laboratory data obtained during the first 24 hours after admission. The data indicated that the following nine findings were associated with the severity of disease: age of at least 65 years, an underlying disease of (31) the respiratory or central nervous system, dyspnea, a pulse rate of at least 90 beats per minute, a respiratory rate of at least 25 breaths per minute, an albumin concentration no greater than 3.5 g/dl, a blood urea nitrogen level of at least 20 mg/dl, a PaO2 no greater than 60 mmHg or an SaO2 no greater than 90%, and a high score on a scale of the extent of roentgenographic evidence of pulmonary infiltrates. Patients in whom these are found be managed carefully.     

Performance management of public–private collaboration in innovation

The open innovation literature has highlighted that more focus should be placed on non‐pecuniary sources such as public research institutes (PRIs) and their performance management (PM), while innovation network studies have highlighted the growing importance of universities and PRIs in public‐private research partnerships. Building on PM capability and portfolio management perspectives, this research aims is to examine the relationship between knowledge resources and collaboration outcome in such public‐private collaborations, and the mediating role of senior management team's (SMT) ability to govern project portfolio approval and management processes. Examining 153 innovation commercialization collaboration projects between PRIs and firms in Singapore, our study has made several significant contributions to the existing research on innovation and performance in public‐private partnership. First, we empirically demonstrate that there is a direct positive relationship between PRIs' knowledge resources and collaboration outcome. Second, our findings establish that the PRIs' SMT ability to govern project portfolio processes mediates this positive relationship. Third, this research highlights that the SMT ability to govern project portfolio processes fully mediates the conversion of market knowledge into innovation. Only partial mediation is observed in the case of technological knowledge, which directly creates value by virtue of generating discoveries or breakthroughs.     

Development of flexible joints for a humanoid robot that walks on an oscillating plane

In this study, we develop flexible joints for a humanoid robot that walks on an oscillating plane and discuss their effectiveness in compensating disturbances. Conventional robots have a rigid frame and are composed of rigid joints driven by geared motors. Therefore, disturbances, which may be caused by external forces from other robots, obstacles, vibration and oscillation of the surface upon which the robot is walking, and so on, are transmitted directly to the robot body, causing the robot to fall. To address this problem, we focus on a flexible mechanism. We develop flexible joints and incorporate them in the waist of a humanoid robot; the experimental task of the robot is to walk on a horizontally oscillating plane until it reaches the desired position. The robot with the proposed flexible joints, reached the goal position despite the fact that the controller was the same as that used for a conventional robot walking on a static plane. From these results, we conclude that our proposed mechanism is effective for humanoid robots that walk on an oscillating plane.     

Fatigue crack growth of PMMA in organic agents

Crack growth tests under cyclic loading were executed at 295 K in various organic agents using compact tension and pure bending specimens of polymethylmethacrylate (PMMA). The cyclic frequencies f for the two kinds of test were 0.4 to 1 and 33 Hz, respectively. Two interesting features are pointed out: (i) transitional behaviour is observed on a crack growth rate against stress intensity factor range K diagram, and (ii) the fatigue fracture surfaces tested in highly viscous agents are covered with a new type of striation named wavy striation, as reported previously. The crack growth rate at the transition was analysed based on fluid flow through the pores within the craze forming at the crack tip. The wavy striation was also investigated by use of the theory of meniscus instability. It is found that both the phenomena may be well described by a parameter P = T(K) ²/f where T and are the surface tension and viscosity of the organic agents, respectively.     

Evaluating J‐integral from Displacement Fields Measured by Digital Image Correlation

Path integral, domain integral and least squares methods for evaluating J‐integral from measured displacement fields for a power‐law hardening material are described in this paper. The values of the J‐integral are evaluated by applying the path and domain integral methods to the displacement fields obtained by elastoplastic finite element analysis and the displacement fields obtained through the measurement using digital image correlation. Results show that the values obtained by the domain integral method are slightly better than those by the path integral method, because the domain integral method efficiently uses the full‐field measurement data. The values of the J‐integral are also evaluated by the least squares method with the Hutchinson, Rice, and, Rosengren displacement fields. Results show that the J‐integral can be obtained by the least squares method simply and easily without any calculation of the integration. The J‐integral values obtained by the least squares method agree well with the values obtained using other methods. Because J‐integral can be evaluated easily by any method described in this paper, it is expected that these methods are applicable to various fracture problems during experimental evaluation of structural components.     

Usefulness of a nonmachinery based system for the reinfusion of cell-free and concentrated autogenous ascitic fluid

A nonmachinery based system using gravity dependent flow for the treatment and reinfusion of ascitic fluid was developed, and its usefulness was assessed. In a preliminary study using bovine plasma, samples with protein concentrations below 5.0 g/dl were found to be treatable with this system. Bovine plasma containing blood, prepared to 0.5% hematocrit and with a protein concentration of 3.0 g/dl, was also treatable. We conducted a clinical study of 1,799 treatment sessions (1,495 using a machinery based system and 304 using a nonmachinery based system) of 343 patients with ascites refractory to various treatments. The recovery ratio of protein from the original ascitic fluid was 96% using the nonmachinery based system and 77% with the machinery based system (p < 0.01). Of 253 continuous reinfusions of ascitic fluid using the nonmachinery based system, the original ascitic fluid at protein concentrations below 2.5 g/dl was treatable. Original ascitic fluid below a hematocrit of 0.7% (protein concentration, 1.4 g/dl) was also treatable. This new procedure was simple and time and labor saving; the high recovery ratio of protein also demonstrated the usefulness of the new system.     

Mechanism of synergism between antimicrobial peptides magainin 2 and PGLa

The antimicrobial peptides magainin 2 and PGLa, discovered in the skin of the African clawed frog, Xenopus laevis, exhibit marked synergism [Westerhoff, H. V., Zasloff, M., Rosner, J. L., Hendler, R. W., de Waal, A., Vaz Gomes, A., Jongsma, A. P. M., Riethorst, A., and Juretic, D., Eur. J. Biochem. 228, 257-264 (1995)], although the mechanism is not yet clear. They are believed to kill bacteria by permeabilizing membranes. In this study, we examined the interactions of these peptides in lipid bilayers. PGLa, like magainin 2, preferentially interacts with acidic lipids, forming an amphipathic helix. The peptide induces the release of a water-soluble dye, calcein, entrapped within liposomes. The coexistence of magainin 2 enhances membrane permeabilization, which is maximal at a 1:1 molar ratio. Fluorescence experiments using L18W-PGLa revealed that both peptides form a stoichiometric 1:1 complex in the membrane phase with an association free energy of -15 kJ/mol. Single amino acid mutations in magainin 2 significantly altered the synergistic activity, suggesting that precise molecular recognition is involved in complex formation. The complex as well as each component peptide form peptide-lipid supramolecular complex pores, which mediate the mutually coupled transbilayer transport of dye, lipid, and the peptide per se. The rate of pore formation rate is in the order complex >/= PGLa > magainin 2, whereas the pore lifetime is in the order magainin 2 > complex > PGLa. Therefore, the synergism is a consequence of the formation of a potent heterosupramolecular complex, which is characterized by fast pore formation and moderate pore stability.     

A Systematic Investigation on Leaky Characteristics for NRD Guide with Arbitrary Profile of Cross-Section

The leaky characteristics of the NRD guide with arbitarary profile of cross section are systematically studied by a method which combines staircase approximation with multimode network theory and mode-matching procedure. Emphasis is laid on the investigation of the effect of the different profile dimensions on the leakage characteristics of the NRD guide. Extensive numerical results are given to establish useful guidelines for the design of some new types of NRD guide leaky wave antennas.