Estimation of Driver Inattention to Forward Objects Using Facial Direction with Application to Forward Collision Avoidance Systems

In forward collision avoidance systems, warnings may be provided more effectively if the underlying timing is set earlier than normal when the driver’s attention is not in the forward direction of the vehicle. In this regard, we determined the following driver characteristcs: (1) the amount of horizontal facial rotation needed to keep track of a moving object in the driver’s field of view increases significantly when the horizontal viewing angle of that target object exceeds 20 degrees, (2) when the driver’s face is oriented in the forward direction, the horizontal angle of facial rotation falls within 15 degrees, and (3) the reaction time to warning lengthens in accordance with the increase in the horizontal viewing angle. In the context of forward collision warning systems, we have determined the difference in the distribution of the driver’s horizontal facial rotation angle, for cases when the driver’ attention was and was not directed to objects in the forward direction of the vehicle. Furthermore, we have measured the reaction time to warning when the driver’s face was not directed forward. Last, our findings were successfully applied to issue the onset timing of a forward collision warning system

A Five-Year-Old Boy with Marked Hypergastrinemia Associated with H. pylori Infection

A 5-year-old boy was referred to our department for persistent epigastric discomfort. Serum gastrin level was 635 pg/ml with a pepsinogen (PG) I level of 102.7 ng/ml and a PG I/II ratio of 23.2, indicating a hyperacidic state. Upper gastrointestinal endoscopy showed normal gastric mucosal folds and no abnormalities including no gastric mucosal atrophy. To investigate the cause of hypergastrinemia, a Ca injection test was performed and the patient showed no definitive response to a large load of Ca. Contrast-enhanced dynamic CT revealed no space-occupying lesions. The results from these two studies were not consistent with the presence of gastrinoma. A urea breath test showed 2.8%, and a test for the fecal H. pylori antigen was positive. Since H. pylori infection was considered to be a possible cause of hypergastrinemia, eradication therapy was introduced. The therapy was shown to be successful by using a repeated urea breath test that showed a normalization to 0.6%. 7 months after the therapy blood examination showed a gastrin level of 191 pg/ml, a PG I level of 36.7 ng/ml, and a PG I/II ratio of 7.3. An immunostaining study of the gastric mucosa suggested that a decrease in somatostatin secretion due to a reduction in D cell population might have induced hypergastrinemia in this case. In children with H. pylori infection showing marked hypergastrinemia, immunohistochemical examination and therapeutic diagnosis by eradication may be helpful in the differential diagnosis of gastrinoma