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Monthly scheduling for elevator maintenance engineers is not only as complex as a large scale travelling salesman problem of several hundreds cities, but also involves more than 100 complex, exceptional and rather emotional conditions such as customer satisfaction and working conditions. An AI system for this scheduling was developed and has been practically used for more than seven years. However, above-mentioned conditions are different monthly, yearly among each of hundreds of maintenance bases in the whole country. Therefore, knowledge refinement cost is quite expensive compared with that needed for ordinary software systems or simple expert systems. In this paper, the problems of the knowledge refinement in this scheduling system are analyzed, and to overcome these problems, two (naive/elaborate case-based) approaches incorporating case-based knowledge are proposed for efficient knowledge refinement of a practical complex AI scheduling system. Experts mostly accepted schedules generated by knowledge refined through either naive or elaborate case-based approaches, though they had been seriously complaining about those generated by knowledge refined for about 4 years without using these approaches.
In this study, damage evaluation of RC column subjected to cyclic loading and evaluation of retrofitting effect were conducted by means of 3 dimensional finite element analysis. Damage area of RC column was evaluated by using averaged compressive strain which was calculated by average of strain within certain area. Bond deteriorated area, in which concrete and rebar behave independently, could also be considered as the damage index of RC column. By comparing with the test result, both averaged compressive strain and bond deteriorated area corresponded to repaired area. Structural behavior of repaired RC column was simulated. As the results, it was confirmed that the damage evaluation method and repairing procedure in this study were suitable to simulate the repaired RC column.
A new conceptual design of a tritium permeation test module assembly was developed, for simulation of tritium permeation in the real plasma facing components and validation of the models and codes for evaluation of the tritium permeation. The assembly was designed for tests using powerful ion sources, which has a capability to simulate condition relevant to that of the ITER divertor. The heat load test of the prototype module has been performed using an electron beam to verify thermal and mechanical behavior of the bonded structure and to assess its structural integrity under the cyclic heat loads. Then, the first tests using tritium ion beam generated by the TPE apparatus at TSTA/LANL with the prototype module was performed and procedure to measure tritium permeated was established. Considerations for tests using the target module with defects generated by neutron irradiation or accelerated ion beam irradiation will be also taken in the new module design.
In this study, we investigated the train operation control in the occurrence of an unexpected delay at a Low Speed Approaching mode (LSA mode) during rush hours.The crowdedness of passengers causes train delays, and the propagation of the delays has become a problem.In order to recover train delays, one approach called LSA mode has been introduced into a railway line.The LSA mode is a traveling mode at which a train approaches a station at lower speed than that at a Normal Speed Approaching mode (NSA mode).Train delays are separated into unexpected delays and expected delays caused by handling passengers.Unexpected delays are caused as by an urgent case and vehicle inspection, and take longer time than expected delays.For recovering unexpected delays, we consider that it is effective to change a traveling mode from an LSA mode to an NSA mode, and propose train operation control at which the LSA mode for trains is cancelled (changing to the NSA mode) at certain places between two stations.The purpose of this study is to investigate effectiveness of train operation control for recovering unexpected delays during rush hours.By computer simulation, we introduced the train operation control at the effective places, and compared differences between with or without the operation control.The result shows that carrying out immediately the operation control in the occurrence of unexpected delays is the most effective timing, and that effectiveness is reduced as the timing for introducing the operation control is delayed.
Abstract For surface structural analysis on monolayer films composed of light elements, we investigated theoretical x‐ray photoelectron diffraction (XPED) patterns from single‐molecule adsorbing surfaces by using both Cr Lα (572.8 eV) and Al Kα (1486.6 eV) excitations. Forward‐scattering peaks and Kikuchi‐like bands were clearly observed in the pattern excited by Al Kα. In contrast, the features of the XPED patterns excited by Cr Lα were more diffuse. However, the circular patterns excited by Cr Lα are clearer than those excited by Al Kα. This result suggests that the use of a lower energy x‐ray source improves XPED structural analysis on ultrathin films composed of light elements. Copyright © 2004 John Wiley & Sons, Ltd.
In recent years, interest in early age concrete cracking has increased due to its effects on the durability and performance of concrete structures. A time-dependent material model and a structural analysis method have been developed to evaluate thermal cracking behavior. To simulate such behavior at early ages, a solidified constitutive model is proposed, which is based on the solidification concept with dependence on time and strain histories. The unified numerical model consists of a Rigid-Body-Spring Network, representing the structural behavior, combined with a truss model to represent heat transfer. Wall concrete structures are analyzed to verify the solidified constitutive model and the overall approach. The proposed model results and the experimental results show reasonable agreement in terms of cracking behavior, stress distributions and structural deformations.
In this paper, the transformation of solid phase and expansion cracking behaviors due to sulfate attack were evaluated by using RBSM-Truss Network Model. This analysis was constructed by combining a hydration model, a diffusion-reaction model, and a crack propagation model in order to evaluate the influence of feedback system of ion transfer through cracks on transformation of solid phase and expansion cracking behavior due to sulfate attack. As a result, the proposed model can predict the change in phase assemblage and physical properties due to hydration process and the change in the transformation of solid phase and the distribution of sulfate ion due to sulfate attack. It was found that expansion crack can affect the diffusion process and expansion cracking behavior as the crack behaves as a buffer of sulfate ion.
