39,679 research outputs found

    HaG: Hash graph based key predistribution scheme for multiphase wireless sensor networks

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    Wireless Sensor Networks (WSN) consist of small sensor nodes which operate until their energy reserve is depleted. These nodes are generally deployed to the environments where network lifespan is much longer than the lifetime of a node. Therefore, WSN are typically operated in a multiphase fashion, as in [1-3, 9-10], which use different key pools for nodes deployed at different generations. In multiphase WSN, new nodes are periodically deployed to the environment to ensure constant local and global network connectivity. Also, key ring of these newly deployed nodes is selected from their deployment generation key pool to improve the resiliency of WSN. In this paper, we propose a key predistribution scheme for multiphase WSN which is resilient against permanent and temporary node capture attacks. In our Hash Graph based (HaG) scheme, every generation has its own key pool which is generated using the key pool of the previous generation. This allows nodes deployed at different generations to have the ability to establish secure channels. Likewise, a captured node can only be used to obtain keys for a limited amount of successive generations. We compare the connectivity and resiliency performance of our scheme with other multiphase key predistribution schemes and show that our scheme performs better when the attack rate is low. When the attack rate is high, our scheme still has better resiliency performance inasmuch as using less key ring size compared to the existing multiphase schemes

    Platform Standards, Collusion and Quality Incentives

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    This paper examines how quality incentives are related to the interoperability of competing platforms. Platforms choose whether to operate standardised or exclusively, prior to quality and subsequent price competition. We find that platforms choose a common standard if they can coordinate their quality provision. The actual investment then depends on the cost of quality provision: If rather high, platforms refrain from investment; if rather low, platforms maintain vertically differentiated platforms. The latter case is socially more desirable than exclusivity where platforms do not invest. Nevertheless, quality competition of standardised platforms induces the highest investment and maximum welfare

    On the equidistribution of some Hodge loci

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    We prove the equidistribution of the Hodge locus for certain non-isotrivial, polarized variations of Hodge structure of weight 22 with h2,0=1h^{2,0}=1 over complex, quasi-projective curves. Given some norm condition, we also give an asymptotic on the growth of the Hodge locus. In particular, this implies the equidistribution of elliptic fibrations in quasi-polarized, non-isotrivial families of K3K3 surfaces.Comment: 33 pages. To appear in Journal f\"ur die reine und angewandte Mathematik (Crelles Journal

    Green Valley Galaxies

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    The "green valley" is a wide region separating the blue and the red peaks in the ultraviolet-optical color magnitude diagram, first revealed using GALEX UV photometry. The term was coined by Christopher Martin in 2005. Green valley highlights the discriminating power of UV to very low relative levels of ongoing star formation, to which the optical colors, including u-r, are insensitive. It corresponds to massive galaxies below the star-forming "main" sequence, and therefore represents a critical tool for the study of the quenching of star formation and its possible resurgence in otherwise quiescent galaxies. This article reviews the results pertaining to morphology, structure, environment, dust content and gas properties of green valley galaxies in the local universe. Their relationship to AGN is also discussed. Attention is given to biases emerging from defining the "green valley" using optical colors. We review various evolutionary scenarios and we present evidence for a new, quasi-static view of the green valley, in which the majority of galaxies currently in the green valley were only partially quenched in the distant past and now participate in a slow cosmic decline of star formation, which also drives down the activity on the main sequence, presumably as a result of the dwindling accretion/cooling onto galaxy disks.Comment: Invited review. 13 pages. Comments welcom

    The Prevalence of Children with Special needs In Inclusive Elementary Schools in Iodine Deficiency Area

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    ABSTRACT Purpose:In general, this research aims to recognize the prevalence of CWSN in inclusive elementary school in the iodine deficiency area. The findings of this research are expected to be proceeded to the intervention programs that enables teachers to help CWSN education in inclusive elementary schools in iodine deficiency area. Method: The research approach uses descriptive study which is conducted in 57 inclusive elementary schools with school requirements: (a) the school has a Decree of the local Education Authority as a school for inclusive education, (b) there is a child with special needs (CWSN) in this certain school, and (c) the school has had a special teacher for CWSN.Collected data includes: (a) the number of CWSN according to class, gender and classification, (b) inclusive school teacher profiles and required teachers for inclusive education implementation for CWSN. The method of collecting data for CWSN and their classification using a screening method with screening instruments needed from Directorate of Special Education and Special Services Ministry of National Education in 2010. While the teachers data profiles are collected by questionnaire method developed by researchers. The validity of this data collection instruments is using content validity with expert judgment. Data analysis method is using percentage quantitative-descriptive technique. Findings: The results can be concluded that: (a) the type of slow-learning CWSN most followed by child learning disabilities, mild mental retardation, behavior disturbances, autistic, physically disabled, visually impaired and deaf-mute, (b) most of the teachers need guidebooks and inclusive education technical guidance, compensatory services and curriculum modifications, learning and assessment of learning outcomes in inclusive schools of CWSN

    INFORMATION SYSTEM FOR EDUCATIONAL EVALUATION OF UNIVERSITY'S ACADEMIC ACTIVITIES

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    The system of academic activities in higher education institutions is a program created to enable students and academic activities to communicate with each other. The mainpurpose of the existence of this system is to provide guidance and mentoring to students in their academic direction. Web-based system has been used as a medium for students to obtain information specifically related to academic course of study and learning. The use of the web-based system is to facilitate the process of selecting courses for planning of studies. The aims of this research are to design and implement quality management system based on International Organization for Standardization (ISO) in higher education or university with android and to know the respondents’ reaction regarding the new design quality management system based on ISO in higher education or university with android. The tools that used in this research are hardware and sofware. In this research use quality management system based on ISO 9001 (quality control) and the process of managing the data in the application of Android telephone celuler will use to implement the system to achieve the result of the research. The sample is 15 students of Information System Department students in Diponegoro University. The method analysis use in this research is descriptive analysis. The result of this study is the develop of information systems used in the higher education or university to know the quality management system based on ISO using Android. The information system to know the quality management system based on ISO using Android telephon celluler is very useful and easy to aplicated. New findings/significance that the design of this information system can help to aplicatedquality management system based on ISO using Android. Keywords: ISO, educational system, academic advisor

    Preliminary study on decision making factors to replace medical equipment in hospital

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    Maintaining medical equipment in hospital is a cost-deprived process yet is a crucial process that needs to be looked into. Maintaining is an ongoing process that starts with installation and ended up with disposed. The cost for maintaining equipment is often held a large portion in life cycle costing and huge amount of money need to be allocated to complete this process. The cost invested on maintaining the medical equipment should be worth the value without comprising the safety requirement and regulations. However, there are circumstances where hospitals are unable to decide when to dispose the equipment especially when the equipment reach the end of its life, incur high repairing cost, aging, and frequent failed to function. Management of hospital come into dead end solution as there are lack of proper guidelines on maintaining medical equipment and therefore the equipment may be over maintained or under maintained. This paper provides a review of 100 papers from credible sources on maintaining activities of equipment to identify factors that are important for decision making to replace the medical equipment

    Weyl Geometry as Characterization of Space-Time

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    Motivated by an axiomatic approach to characterize space-time it is investigated a reformulation of Einstein's gravity where the pseudo-riemannian geometry is substituted by a Weyl one. It is presented the main properties of the Weyl geometry and it is shown that it gives extra contributions to the trajectories of test particles, serving as one more motivation to study general relativity in Weyl geometry. It is introduced its variational formalism and it is established the coupling with other physical fields in such a way that the theory acquires a gauge symmetry for the geometrical fields. It is shown that this symmetry is still present for the red-shift and it is concluded that for cosmological models it opens the possibility that observations can be fully described by the new geometrical scalar field. It is concluded then that this reformulation, although representing a theoretical advance, still needs a complete description of their objects.Comment: 12 page

    CP Violation in B Decays within QCD Factorization

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    We analyze the extraction of weak phases from CP violation in Bπ+πB\to\pi^+\pi^- decays. By combining the information on mixing induced CP violation in Bπ+πB\to\pi^+\pi^-, namely SππS_{\pi\pi}, with the precision observable sin2β\sin 2\beta obtained from the ``gold-plated''mode BψKSB\to\psi K_S, we propose the determination of the unitarity triangle. We also discuss alternative ways to analyze SππS_{\pi\pi} which can be useful if new physics affects BdB_d--Bˉd\bar B_d mixing. Predictions and uncertainties for rr and ϕ\phi in QCD factorization are examined in detail. It is pointed out that a simultaneous expansion in 1/mb1/m_b and 1/NC1/N_C leads to interesting simplifications. At first order infrared divergences are absent, while the most important effects are retained. Independent experimental tests of the factorization framework are briefly discussed.Comment: 3 pages; 2 figures; To appear in the proceedings of International Europhysics Conference on High-Energy Physics (HEP 2003), Aachen, Germany, 17-23 Jul 200
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