This paper presents a log-transformed model-based performance analysis system for analyzing and improving manufacturing performance of the smart factory in the display business. Two years of data related to traditional manufacturing performance such as Cycle-time, WIP(Work-In-Process), and Throughput were investigated from the smart factory that producing the display for this research. We assessed manufacturing competitiveness based on how the operational level of automation affects improvements in manufacturing performances. We analyzed functional relationships between the indicators were derived using logtransformed regression analysis how the manufacturing performance indicators change according to the operational level of smart factory automation. As a result, we knew that the 170K production, which was planned capacity in the line design phase, achieved by running an automation level of only 59%. Based on this research, we suggest building an autopoietic optimize performance model to improving manufacturing competitiveness of smart manufacturing.

In the present study, we investigated the physiological effects of smartphone use at night when the display luminance and white balance were differently manipulated. Two levels of luminance and two types of white balance were combined to form four types of displays. Subjects were instructed to use smartphones between 23:00 to 01:00 twice a week for two weeks, and for each trial, subjects were given one of the four display types. Melatonin concentration in the saliva, body temperature and heart rate were measured before and after each experiment. The experimental result showed that the low luminance display supported melatonin secretion and thermoregulation compared to the high luminance display. With regard to the white balance, higher melatonin level was observed when using the display that filtered blue light. The low luminance display together with yellowish tint best supported restful sleep at night in terms of every physiological response. This study collectively demonstrates that bright and blue light emitted from smartphone displays adversely affect melatonin secretion, body temperature, and heart rate, and therefore, suggests the use of a display with low luminance or a display that filters blue light for a restful sleep at night.