4,264 research outputs found
The cytochemical localization of adenyl cyclase activity in rat sublingual gland
Adenyl cyclase activity in mucous acinar cells and serous demilune cells of the rat sublingual gland was localized cytochemically. After incubation with adenylyl-imidodiphosphate (AMP-PNP) as substrate, deposits of reaction product are found along the cell membranes bordering the secretory surfaces of serous demilune cells. These are the membranes which participate directly in secretion by fusing with the granule membranes. The granule membranes of the demilune cells do not reveal reaction product, but the membranes of the granules which are fused with and become part of the cell membrane do show deposits. Thus, it appears that the cell membranes which fuse with granule membranes during secretion are associated with a high level of adenyl cyclase activity. In support of this, the luminal membranes of the mucous acinar cells which do not fuse with granule membranes during secretion are not associated with detectable amounts of adenyl cyclase activity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49675/1/1001440407_ftp.pd
On The Stability Problem of Quadratic Functional Equations in 2-Banach Spaces
In this paper, we investigate the stability problem in the spirit of Hyers-Ulam, Rassias and Gavruta for the quadratic functional equation: f(2x + y) + f(2x - y) = 2f(x + y) + 2f(x - y) + 4f(x) - 2f(y) in 2-Banach spaces. These results extend the generalized Hyers-Ulam stability results by the quadratic functional equation in normed spaces to 2-Banach spaces
Real-time analysis of aggregate network traffic for anomaly detection
The frequent and large-scale network attacks have led to an increased need for
developing techniques for analyzing network traffic. If efficient analysis tools were
available, it could become possible to detect the attacks, anomalies and to appropriately
take action to contain the attacks before they have had time to propagate across the
network.
In this dissertation, we suggest a technique for traffic anomaly detection based on
analyzing the correlation of destination IP addresses and distribution of image-based
signal in postmortem and real-time, by passively monitoring packet headers of traffic.
This address correlation data are transformed using discrete wavelet transform for
effective detection of anomalies through statistical analysis. Results from trace-driven
evaluation suggest that the proposed approach could provide an effective means of
detecting anomalies close to the source. We present a multidimensional indicator using
the correlation of port numbers as a means of detecting anomalies.
We also present a network measurement approach that can simultaneously detect,
identify and visualize attacks and anomalous traffic in real-time. We propose to
represent samples of network packet header data as frames or images. With such a
formulation, a series of samples can be seen as a sequence of frames or video. Thisenables techniques from image processing and video compression such as DCT to be
applied to the packet header data to reveal interesting properties of traffic. We show that
??scene change analysis?? can reveal sudden changes in traffic behavior or anomalies. We
show that ??motion prediction?? techniques can be employed to understand the patterns of
some of the attacks. We show that it may be feasible to represent multiple pieces of data
as different colors of an image enabling a uniform treatment of multidimensional packet
header data.
Measurement-based techniques for analyzing network traffic treat traffic volume
and traffic header data as signals or images in order to make the analysis feasible. In this
dissertation, we propose an approach based on the classical Neyman-Pearson Test
employed in signal detection theory to evaluate these different strategies. We use both of
analytical models and trace-driven experiments for comparing the performance of
different strategies. Our evaluations on real traces reveal differences in the effectiveness
of different traffic header data as potential signals for traffic analysis in terms of their
detection rates and false alarm rates. Our results show that address distributions and
number of flows are better signals than traffic volume for anomaly detection. Our results
also show that sometimes statistical techniques can be more effective than the NP-test
when the attack patterns change over time
Epidemic Response Coordination Networks in âLiving Documentsâ
Response plans developed thoroughly are suggestive of a successful action, but there is a gap in the literature with respect to the way concerted efforts among organizations are planned and change during crises. Using organizational network data extracted from the South Korean governmentâs MERS response manuals, we examined the changes in the response coordination network planned during the epidemicâs distinct stages. The greatest difference in predicting tie formation was found in the networks planned before the event and revised during the outbreak. Local and governmental actors tend to form more ties consistently in the revised manuals. Two actors that are intended to transfer medical and/or personnel resources tend to form more ties across all stages. These findings suggest that transferring material and/or human resources are key activities in the epidemic response and planners tend to increase the connection of local and governmental actors over time
Homomorphisms and derivations on C*-ternary algebras assocoated with a generalized Cauchy-Jensen type additive functional equation
In this paper, we prove the generalized Hyers-Ulam stability of CâËâ-ternary homomorphisms and CâËâ-ternary derivations on CâËâ-ternary algebras associated with the generalized Cauchy-Jensen type additive functional equation
for all xi; xj âËË X where n âËË Z+ is a fixed integer with n ââ°ÂĽ 3.
 
- âŚ