An innovative camera-based speckle contrast diffuse correlation tomography (scDCT) technology has been developed recently, which enables noncontact, noninvasive, high-density, 3D imaging of cerebral blood flow (CBF) distributions. This study demonstrated the capability and safety of scDCT technique for imaging of CBF distributions in a neonatal piglet model of transient ischemic stroke. Moreover, power spectral density analyses of low-frequency oscillations (LFOs) and the network connections over the brain were assessed before and after the induction of acute ischemic stroke. The stroke resulted in a substantial decrease in CBF, attenuations in resting-state LFOs, and functional connectivity disruptions in motor and somatosensory cortices.
Intraventricular hemorrhage (IVH) is the most common neurological complication of prematurity. IVH is a bleeding inside or around ventricles, spaces in the brain containing the cerebrospinal fluid, which occurs as a result of the fragility and immaturity of blood vessels in premature brains. Severe IVH disrupts development of structural and functional connectivity networks, leading to impairments of cerebral development and neurologic deficits. Preterm infants with IVH are prone to alterations in cerebral blood flow (CBF) and associated spontaneous low-frequency fluctuations. However, there are no established noninvasive imaging methods for continuous monitoring of CBF alterations at the bedside in neonatal intensive care units. An innovative CCD/CMOS based speckle contrast diffuse correlation tomography (scDCT) technology has been recently developed in our laboratory, which enables noncontact, noninvasive, and high-density 3D imaging of CBF distributions in deep brain cortex. In the present study, the capability of scDCT technique for noncontact 3D imaging of CBF distributions in a neonatal piglet model of IVH was demonstrated. Moreover, power spectral density analyses of scDCT data were performed to assess alterations in spontaneous low frequency fluctuations in the resting brain, before and after inducing IVH. IVH resulted in a CBF decrease in deep brain cortex. Resting-state spontaneous low-frequency fluctuations after IVH showed attenuations in all frequencies (0.009– 0.08 Hz) compared to the baseline before IVH. In conclusion, scDCT is capable of detecting brain hemodynamic disruptions (reduction in CBF and attenuation in spontaneous low-frequency fluctuations) after IVH, which might be useful for instant management of IVH and associated complications.
Wireless network is more vulnerable to denial of service (DoS) attacks than wired one. In this paper we propose two methods to resist DoS attacks in UMTS-WLAN network, one is active and the other is passive. These two are complementary to each other. In active DoS defense method, a mobile terminal generates an authorized anonymous ID (AAI) using its true ID such as IP address, MAC address, PIN code, or asymmetric key, and substitutes its true ID with the authorized anonymous ID. The mobile terminal may be authenticated by the UMTS-WLAN, however its true ID is anonymous to intending attackers. This method can be used to isolate de-authenticating/disassociating DoS attackers, spoofing power-save DoS attacker, etc. In passive DoS defense method, we propose a trace back scheme. We use covert channels in the header of mobile IP packets to trace back the malicious nodes by embedding some address information of intermediate nodes, and recovering the embedded information by the victim. After the victim successfully traces the attacking paths from malicious nodes, it can segregate the malicious nodes and protect itself. This method can be used to resist DoS attacks of mass-produced junk message congestions.
KEYWORDS: Video, Video surveillance, Standards development, Homeland security, Modulation, Cameras, Sensors, Video compression, Orthogonal frequency division multiplexing, Data processing
The authors are developing a flexible sensor network with numerous potential uses. This paper presents one constructive application of the sensor integration platform and network. The theory of operation is as follows. Multiple sensing/processing nodes are scattered about a 30-mile radius on land. Each node has the capability to handle up to a few different sensors based on user needs. The nodes operate autonomously while continuously acquiring data and process the information locally. The information deemed relevant to the system operator is uplinked to a base station at optimal intervals. Further data collection takes place at the base station where an operator can take appropriate action. Communication between the base station and nodes is based upon the emerging IEEE 802.16 standard. This enables broadband level information transfer at ranges capable of covering entire metropolitan areas.
The application discussed in this paper is a homeland security monitoring system. This system would make use of a variety of nodes to collect data from surveillance cameras at border crossings and high value assets, water contamination sensors, weather sensors, and other sensors the user sees necessary. A technical description of the system architecture, its benefits, and limitations will be included. The utility of the 802.16 standard will also be incorporated in the paper.
That terrorists hijacked the airplanes and crashed the World Trade Center is disaster to civilization. To avoid the happening of hijack is critical to homeland security. To report the hijacking in time, limit the terrorist to operate the plane if happened and land the plane to the nearest airport could be an efficient way to avoid the misery. Image processing technique in human face recognition or identification could be used for this task.
Before the plane take off, the face images of pilots are input into a face identification system installed in the airplane. The camera in front of pilot seat keeps taking the pilot face image during the flight and comparing it with pre-input pilot face images. If a different face is detected, a warning signal is sent to ground automatically. At the same time, the automatic cruise system is started or the plane is controlled by the ground. The terrorists will have no control over the plane. The plane will be landed to a nearest or appropriate airport under the control of the ground or cruise system. This technique could also be used in automobile industry as an image key to avoid car stealth.
KEYWORDS: Digital watermarking, Video, Video compression, Visualization, Wavelet transforms, Principal component analysis, Motion models, Directed energy weapons, Sensors, Optical tracking
This paper presents a video watermarking scheme for copyright notification and protection. Each video frame is clustered into high motion and low motion regions. Dual watermarks are designed by exploiting video motion, perceptual characteristics, and some other informative cues. They are embedded into certain macroblocks in these two regions respectively. The watermark in the low motion region is resilient to frame-level attacks such as frame dropping, frame averaging and frame reshuffling. The watermark in the high motion region is robust to statistical attacks. The detection does not need the original frame or any a priori index information of frames in video sequence. Good invisibility as well as strong robustness can be obtained. The experimental results validate the effectiveness of the system.
This paper presents a visible watermarking system using
perceptual models.
%how and why
A watermark image is overlaid translucently onto a primary image,
for the purposes of immediate claim of copyright, instantaneous
recognition of owner or creator,
or deterrence to piracy of digital images or video.
%perceptual
The watermark is modulated by exploiting
combined DCT-domain and
DWT-domain perceptual models. % so that the watermark is visually uniform.
The resulting watermarked image is
visually pleasing and unobtrusive.
The location, size and strength of the watermark
vary randomly with the underlying image. The randomization
makes the automatic removal of the watermark difficult even though
the algorithm is known publicly but the key to the random sequence generator.
The experiments demonstrate that the watermarked images have pleasant
visual effect and strong robustness. The watermarking system can be used in
copyright notification and protection.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.