Utilization of a Gas-Sensing System to Discriminate Smell and to Monitor Fermentation during the Manufacture of Oolong Tea Leaves.

The operational duration of shaking tea leaves is a critical factor in the manufacture of oolong tea; this duration influences the formation of its flavor and fragrance. The current method to control the duration of fermentation relies on the olfactory sense of tea masters; they monitor the entire process through their olfactory sense, and their experience decides the duration of shaking and setting. Because of this human factor and olfactory fatigue, it is difficult to define an optimum duration of shaking and setting; an inappropriate duration of shaking and setting deteriorates the quality of the tea. In this study, we used metal-oxide-semiconductor gas sensors to establish an electronic nose (E-nose) system and tested its feasibility. This research was divided into two experiments: distinguishing samples at various stages and an on-line experiment. The samples of tea leaves at various stages exhibited large differences in the level of grassy smell. From the experience of practitioners and from previous research, the samples could be categorized into three groups: before the first shaking (BS1), before the shaking group, and after the shaking group. We input the experimental results into a linear discriminant analysis to decrease the dimensions and to classify the samples into various groups. The results show that the smell can also be categorized into three groups. After distinguishing the samples with large differences, we conducted an on-line experiment in a tea factory and tried to monitor the smell variation during the manufacturing process. The results from the E-nose were similar to those of the sense of practitioners, which means that an E-nose has the possibility to replace the sensory function of practitioners in the future.

On Anonymizing Medical Microdata with Large-Scale Missing Values - A Case Study with the FAERS Dataset.

As big data analysis becomes one of the main driving forces for productivity and economic growth, the concern of individual privacy disclosure increases as well, especially for applications accessing medical or health data that contain personal information. Most contemporary techniques for privacy preserving data publishing follow a simple assumption-the data of concern is complete, i.e., containing no missing values, which however is not the case in the real world. This paper presents our endeavors on inspecting the effect of missing values upon medical data privacy. In particular, we inspected the US FAERS dataset, a public dataset containing adverse drug events released by US FDA. Following the presumption of current anonymization paradigm-the data should contain no missing values, we investigated three intuitive strategies, including or excluding missing values or executing imputation, to anonymize the FAERS dataset. Our results demonstrate the awkwardness of these intuitive strategies in handling data with a massive amount of missing values. Accordingly, we propose a new strategy, consolidation, and the corresponding privacy protection model and anonymization algorithm. Experimental results show that our method can prevent privacy disclosure and sustain the data utility for ADR signal detection.