Using Capacitance Sensor to Extract Characteristic Signals of Dozing from Skin Surface

Skin is the largest organ of the human body and a physiological structure that is directly exposed to the environment. From a theoretical perspective, numerous physiological and psychological signals use the skin as a medium for input and output with the outside world. Therefore, the skin is considered an optimal signal interception point when developing noninvasive, direct, and rapid signal exploration devices. To date, skin signal interceptions are predominantly performed by measuring skin impedance. However, this method is prone to interference such as sweat secretion, salt accumulation on the skin, and muscle contractions, which may result in a substantial amount of interference and erroneous results. The present study proposes novel and effective methods for skin signal interception, such as using a nested probe as a sensor to measure capacitance to be further processed as physiological and psychological signals. The experimental results indicate that the capacitance curve for the transition between wakefulness and dozing exhibits significant changes. This change in the curve can be analyzed by computer programs to clearly and rapidly determine whether the subject has entered the initial phases of sleep

A Steganographic Method by Pixel-Value Differencing and Exploiting Modification Direction

[[abstract]]In this paper, we shall propose a new image steganographic scheme for embedding secret messages into a gray-valued cover image and capable of producing a secret-embedded image that is totally indistinguishable from the original image by the human eye. In addition, the proposed scheme avoids the falling-off-boundary problem by using the Pixel-Value Differencing (PVD) and the Exploiting Modification Direction (EMD). A cover image is partitioned into non-overlapping blocks of four consecutive pixels. First, we derive two pieces of difference value from four consecutive pixels by utilizing the PVD. The hiding capacity of the four consecutive pixels depends on the two pieces of difference value. In other words, the smoother area is, the less secret data can be hidden; on the contrary, the more edges an area has, the more secret data can be embedded, and then secret data embedded by using the PVD. In order to provide high payload capacity, the remainder of two average values of the four consecutive pixels can be computed, and the two average values are capable of embedding secret data by using the EMD. The embedded secret message can be extracted from the resulting stego-image without referencing the original cover image. Moreover, a pseudo-random mechanism may be used to achieve secrecy protection. The experimental results show that the proposed scheme is capable of providing a great payload capacity, and the image quality of the embedded image is better than PVD for a gray-level image

Password Authentication Schemes: Current Status and Key Issues

[[abstract]]Password authentication is one of the simplest and the most convenient authentication mechanisms to deal with secret data over insecure networks. It is more fre- quently required in areas such as computer networks, wireless networks, remote login systems, operation sys- tems, and database management systems. In this paper, we shall present the result of our survey through all cur- rently available password-authentication-related schemes and get them classified in terms of several crucial criteria. To be critical, most of the existing schemes are vulnera- ble to various attacks and fail to serve all the purposes an ideal password authentication scheme should. In order to see how different password authentication schemes com- pare in different situations, we define all possible attacks and goals that an ideal password authentication scheme should withstand and achieve. We should hope that the attacks and goals we offer here can also help future re- searchers develop better schemes