1,661 research outputs found
Energy Efficient Ant Colony Algorithms for Data Aggregation in Wireless Sensor Networks
In this paper, a family of ant colony algorithms called DAACA for data
aggregation has been presented which contains three phases: the initialization,
packet transmission and operations on pheromones. After initialization, each
node estimates the remaining energy and the amount of pheromones to compute the
probabilities used for dynamically selecting the next hop. After certain rounds
of transmissions, the pheromones adjustment is performed periodically, which
combines the advantages of both global and local pheromones adjustment for
evaporating or depositing pheromones. Four different pheromones adjustment
strategies are designed to achieve the global optimal network lifetime, namely
Basic-DAACA, ES-DAACA, MM-DAACA and ACS-DAACA. Compared with some other data
aggregation algorithms, DAACA shows higher superiority on average degree of
nodes, energy efficiency, prolonging the network lifetime, computation
complexity and success ratio of one hop transmission. At last we analyze the
characteristic of DAACA in the aspects of robustness, fault tolerance and
scalability.Comment: To appear in Journal of Computer and System Science
A Clustering-based Location Privacy Protection Scheme for Pervasive Computing
In pervasive computing environments, Location- Based Services (LBSs) are
becoming increasingly important due to continuous advances in mobile networks
and positioning technologies. Nevertheless, the wide deployment of LBSs can
jeopardize the location privacy of mobile users. Consequently, providing
safeguards for location privacy of mobile users against being attacked is an
important research issue. In this paper a new scheme for safeguarding location
privacy is proposed. Our approach supports location K-anonymity for a wide
range of mobile users with their own desired anonymity levels by clustering.
The whole area of all users is divided into clusters recursively in order to
get the Minimum Bounding Rectangle (MBR). The exact location information of a
user is replaced by his MBR. Privacy analysis shows that our approach can
achieve high resilience to location privacy threats and provide more privacy
than users expect. Complexity analysis shows clusters can be adjusted in real
time as mobile users join or leave. Moreover, the clustering algorithms possess
strong robustness.Comment: The 3rd IEEE/ACM Int Conf on Cyber, Physical and Social Computing
(CPSCom), IEEE, Hangzhou, China, December 18-20, 201
SVMTriP: A Method to Predict Antigenic Epitopes Using Support Vector Machine to Integrate Tri-Peptide Similarity and Propensity
Identifying protein surface regions preferentially recognizable by antibodies (antigenic epitopes) is at the heart of new immuno-diagnostic reagent discovery and vaccine design, and computational methods for antigenic epitope prediction provide crucial means to serve this purpose. Many linear B-cell epitope prediction methods were developed, such as BepiPred, ABCPred, AAP, BCPred, BayesB, BEOracle/BROracle, and BEST, towards this goal. However, effective immunological research demands more robust performance of the prediction method than what the current algorithms could provide. In this work, a new method to predict linear antigenic epitopes is developed; Support Vector Machine has been utilized by combining the Tri-peptide similarity and Propensity scores (SVMTriP). Applied to non-redundant B-cell linear epitopes extracted from IEDB, SVMTriP achieves a sensitivity of 80.1% and a precision of 55.2% with a five-fold cross-validation. The AUC value is 0.702. The combination of similarity and propensity of tri-peptide subsequences can improve the prediction performance for linear B-cell epitopes. Moreover, SVMTriP is capable of recognizing viral peptides from a human protein sequence background. A web server based on our method is constructed for public use. The server and all datasets used in the current study are available at http://sysbio.unl.edu/SVMTriP
VI-Band Follow-Up Observations of Ultra-Long-Period Cepheid Candidates in M31
The ultra-long period Cepheids (ULPCs) are classical Cepheids with pulsation
periods exceeding days. The intrinsic brightness of ULPCs are ~1
to ~3 mag brighter than their shorter period counterparts. This makes them
attractive in future distance scale work to derive distances beyond the limit
set by the shorter period Cepheids. We have initiated a program to search for
ULPCs in M31, using the single-band data taken from the Palomar Transient
Factory, and identified eight possible candidates. In this work, we presented
the VI-band follow-up observations of these eight candidates. Based on our
VI-band light curves of these candidates and their locations in the
color-magnitude diagram and the Period-Wesenheit diagram, we verify two
candidates as being truly ULPCs. The six other candidates are most likely other
kinds of long-period variables. With the two confirmed M31 ULPCs, we tested the
applicability of ULPCs in distance scale work by deriving the distance modulus
of M31. It was found to be mag. The large error
in the derived distance modulus, together with the large intrinsic dispersion
of the Period-Wesenheit (PW) relation and the small number of ULPCs in a given
host galaxy, means that the question of the suitability of ULPCs as standard
candles is still open. Further work is needed to enlarge the sample of
calibrating ULPCs and reduce the intrinsic dispersion of the PW relation before
re-considering ULPCs as suitable distance indicators.Comment: 13 pages, with 14 Figures and 4 Tables (one online table). AJ
accepte
Correlation between Office Locations, Corporate Governance and Business Performance
The concept of “corporate governance” developed in an era marked by global economic liberalization, continuing enterprise expansion, and separation enterprise ownership and management trends. Good corporate governance is important to enhance corporate value and national competitiveness. “Locations” refer to spaces wherein human social activities are held. Office activities have become important economic human activities, and enterprise headquarters are the primary places where enterprises issue orders, carry out corporate control, and make decisions. Hence, they are vital to the overall operation of enterprises. Do the locations of enterprise headquarters influence corporate governance quality, and thus, the overall business performance of enterprises? This research analyzes Taiwan's listed and over-the-counter companies. As per empirical results: (1) Corporate business performance significantly correlates with corporate governance and office locations, with a significant difference between various areas, and (2) the quality of corporate governance of Taiwanese enterprises significantly correlates and varies with their office locations.
Keywords: Corporate Governance, Business Performance, Location Theory
JEL Classifications: G34, M10, R3
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