Search Results

A prototype navigation system with cellular phone access to an information service center was constructed and evaluated. Center personnel can also operate the system remotely, in addition to providing traffic information and information for more enjoyable travel. Real-time conversation with a center operator is also possible. The system was rated positively by most of the subjects, especially the real-time voice service. This paper describes the car navigation market and cellular phone market in Japan, the system configuration, evaluation results and possible solutions to problems in the system. It also touches on the outlook for future car navigation systems and information services.

Natural speech contains a wide variety of expressions, making it much more difficult to recognize than specified verbal commands. We have developed a method using a language model template to generate language models capable of recognizing manifold expressions. This template method is designed on the basis of the modification structure of keywords. The evaluation results for a language model generated with this method showed that it allowed 630,000 command patterns with a high recognition rate of 96%. The results also revealed that the processing speed and memory used for speech recognition with this language model were at a practical level.

It is obvious that the quality of telematics services depends in particular on the radio wave environment of the cellular phones used as the communication infrastructure. There is a need to develop the technological capabilities for enabling users to enjoy stable communication without being conscious of changes in the surrounding radio wave environment. As one solution to this problem, this paper proposes a partial download function that divides the desired content data into smaller quantities for transmission and also selects areas with a good radio wave environment for downloading data while suspending communication in places where reception is poor. The results of driving tests are presented to demonstrate the effectiveness of this partial download function.

This paper proposes a new voice and data wireless communication method for telematics services. Data-voice (DV) modems have conventionally been used for simultaneous transmission of voice and data. With this method, however, one line is split between the data part and voice part. Lost data are retransmitted, but the voice signal is not resent because voice communication requires a real-time characteristic. The new voice and data wireless communication method proposed here switches voice to a voice line and data to a data line.

This paper describes an Expert System which can diagnose Nissan's Electronic Concentrated engine Control System (ECCS). This system employs the production system as its AI technique. The knowledge of expert mechanics on cause and effect relations is expressed in “problem - cause” pairs. The development of this prototype system for engine troubleshooting has confirmed that it is possible to systematize and store the knowledge of experts in a computer. Now by, adding more sophisticated expert knowledge, this system can be made an effecvtive tool in providing quick and accurate diagnosis.

There are many production robots used at car manufacturing plants, and each of them is fitted with several reducers. A breakdown of one of these reducers may cause a huge loss due to the stoppage of all production lines. Therefore, condition-based maintenance is currently being used to predict failures by predetermined thresholds for average and standard deviations. However, this method can cause many false alarms or some false negatives. There are some ways of suppressing false alarms, such as detecting a change in the probability density function. However, when false alarms are suppressed using the probability density function in the operational range, some false negatives may occur, leading to a breakdown of a reducer and huge loss. A false negative is caused by overlooking an anomaly with slight changes and it is difficult to detect using only the probability density function.