An Object Model for Flexible Distributed Systems

this paper we describe a new model for constructing operating systems and applications in an integrated fashion. Compared to current approaches we provide high-level primitives for supporting distributed and parallel applications. We also provide the flexibility to configure both applications and kernels to only include the functionality that is actually used. The model we describe is based on objects. Objects are used to structure both applications programs and operating system kernels. They also provide the application interface to the operating system kernel, and access to hardware devices for both kernels and applications. By providing structuring mechanisms for large (distributed) objects, we believe that applications will be are easier to build. At the same time we provide flexibility by allowing extensions of operating system kernels and applications with new objects at run time[8], and by providing a way to bind to objects dynamically. An important aspect of a distributed system is the scalability of the system [6]. A scalable system should not depend on centralized resources or on algorithms that need global information. At the same time, a flexible system can use different algorithms depending on the situation. For example, the use of broadcasting and multicasting on a local Ethernet can be quite effective but should be avoided on a world wide scale. In this paper we discuss an object model that provides two kinds of objects: local objects and distributed objects. In Section 2 we describe the nondistributed (local) objects, followed by distributed objects in Section 3. We compare our work to that of others in Section 4. 2 Local object

Towards Object-based Wide Area Distributed Systems

In order to facilitate the construction of wide area distributed systems, it is necessary that we adopt a model that simplifies application development. In this position paper we advocate an object-based approach. Our approach allows for flexibility because many of the technical details of distribution, such as communication protocols, consistency rules, etc. can be hidden behind the objects' interfaces. In addition, we allow distributed objects to offer alternative implementations for an interface. A client may choose the most suitable implementation. We discuss the use of distributed objects as the means to this end, and compare our approach to existing ones. 1 Introduction Wide area distributed applications pose varying demands on the underlying operating systems, often making the development of the application itself a difficult task. For example, development of distributed applications often requires the following: ffl Support for expressing communication at a sufficiently high..

Electromagnetic form factors in the J/\psi mass region: The case in favor of additional resonances

Using the results of our recent analysis of e^+e^- annihilation, we plot the curves for the diagonal and transition form factors of light hadrons in the time-like region up to the production threshold of an open charm quantum number. The comparison with existing data on the decays of J/\psi into such hadrons shows that some new resonance structures may be present in the mass range between 2 GeVand the J/\psi mass. Searching them may help in a better understanding of the mass spectrum in both the simple and a more sophisticated quark models, and in revealing the details of the three-gluon mechanism of the OZI rule breaking in K\bar K channel.Comment: Formulas are added, typo is corrected, the text is rearranged. Replaced to match the version accepted in Phys Rev

Computerized cognitive training in prostate cancer patients on androgen deprivation therapy: a pilot study

© 2017, Springer-Verlag GmbH Germany, part of Springer Nature. Purpose: Prostate cancer patients who have undergone androgen deprivation therapy (ADT) may experience cognitive impairment, yet there is an unmet need for nonpharmacological interventions to address cognitive impairment in this population. This study examines the feasibility, acceptability, and preliminary efficacy of a home-based computerized cognitive training (CCT) program to treat cancer-related cognitive impairment. Methods: Sixty men who had received ≥ 3 months of ADT were screened for at least mild cognitive or neurobehavioral impairment and randomized to 8 weeks of CCT or usual care. Follow-up assessments occurred immediately post-intervention or equivalent (T2) and 8 weeks later (T3). The acceptability of CCT was also assessed. Results: Feasibility:A priori feasibility thresholds were partially met (i.e., randomization rate \u3e 50%, retention rate \u3e 70% excluding CCT drop-outs, but \u3c 70% for intent-to-treat). Acceptability: Participants were mostly satisfied with CCT and found it somewhat enjoyable, though barriers to uptake existed. Preliminary efficacy: Linear mixed models indicated significant time by group effects favorable to CCT in reaction time (p =.01), but unfavorable to CCT in verbal and visual memory (ps \u3c .05). Memory was temporarily suppressed in the CCT group at T2, but normalized by T3. There was no effect of CCT on self-reported cognitive functioning, neurobehavioral functioning, nor quality of life. Conclusions: This study provides tentative support for the feasibility and acceptability of CCT to treat mild cognitive impairment in ADT patients. CCT had a beneficial effect on reaction time, but temporarily suppressed memory. CCT’s benefits may be limited to a narrow area of functioning. Larger-scale studies are needed

Hot and repulsive traffic flow

We study a message passing model, applicable also to traffic problems. The model is implemented in a discrete lattice, where particles move towards their destination, with fluctuations around the minimal distance path. A repulsive interaction between particles is introduced in order to avoid the appearance of traffic jam. We have studied the parameter space finding regions of fluid traffic, and saturated ones, being separated by abrupt changes. The improvement of the system performance is also explored, by the introduction of a non-constant potential acting on the particles. Finally, we deal with the behavior of the system when temporary failures in the transmission occurs.Comment: 22 pages, uuencoded gzipped postscript file. 11 figures include

Spacings of Quarkonium Levels with the Same Principal Quantum Number

The spacings between bound-state levels of the Schr\"odinger equation with the same principal quantum number $N$ but orbital angular momenta $\ell$ differing by unity are found to be nearly equal for a wide range of power potentials $V = \lambda r^\nu$, with $E_{N \ell} \approx F(\nu, N) - G(\nu,N) \ell$. Semiclassical approximations are in accord with this behavior. The result is applied to estimates of masses for quarkonium levels which have not yet been observed, including the 2P $c \bar c$ states and the 1D $b \bar b$ states.Comment: 20 pages, latex, 3 uuencoded figures submitted separately (process using psfig.sty

Enhancing Transport Efficiency by Hybrid Routing Strategy

Traffic is essential for many dynamic processes on real networks, such as internet and urban traffic systems. The transport efficiency of the traffic system can be improved by taking full advantage of the resources in the system. In this paper, we propose a dual-strategy routing model for network traffic system, to realize the plenary utility of the whole network. The packets are delivered according to different "efficient routing strategies" [Yan, et al, Phys. Rev. E 73, 046108 (2006)]. We introduce the accumulate rate of packets, {\eta} to measure the performance of traffic system in the congested phase, and propose the so-called equivalent generation rate of packet to analyze the jamming processes. From analytical and numerical results, we find that, for suitable selection of strategies, the dual- strategy system performs better than the single-strategy system in a broad region of strategy mixing ratio. The analytical solution to the jamming processes is verified by estimating the number of jammed nodes, which coincides well with the result from simulation.Comment: 6 pages, 3 figure

Hadroproduction and Polarization of Charmonium

In the limit of heavy quark mass, the production cross section and polarization of quarkonia can be calculated in perturbative QCD. We study the $p_\perp$-averaged production of charmonium states in $\pi N$ collisions at fixed target energies. The data on the relative production rates of \jp and $\chi_J$ is found to disagree with leading twist QCD. The polarization of the \jp indicates that the discrepancy is not due to poorly known parton distributions nor to the size of higher order effects ($K$-factors). Rather, the disagreement suggests important higher twist corrections, as has been surmised earlier from the nuclear target $A$-dependence of the production cross section.Comment: 19 page

Research on China’s Fiscal Policy in the Promotion of Technological Innovation

创新日益成为一个国家、民族兴旺发达的决定性因素，科技进步和技术创新不仅成为时代的主旋律，而且也变成了学术界、产业界、科技界以及中央和地方各级政府讨论经济发展问题的主流话语。企业是技术创新的主体和技术创新体系的中心，因此，促进企业技术创新不仅有利于企业提高其经济效益和增强其市场竞争力，而且有利于促进一国的经济增长。 财税政策作为一种重要的政府政策工具，应在促进企业技术创新过程中发挥重要作用。虽然我国政府制定了多项财政支持政策和一系列的税收优惠政策，从多个方位和不同层面来提高企业技术创新能力、促进和引导技术创新，并取得了一定的成效。然而，目前我国促进企业技术创新的财税政策仍然存在一定的问题，其根...Innovation is increasingly becoming a decisive factor in national prosperity, technological progress and technical innovation has not only become the main theme of the times, but also become the mainstream discourse of the academia, industry, technology and the central or local governments discussing economic development issues. Enterprises is the technological innovation main force and the center...学位：经济学硕士院系专业：经济学院财政系_财政学(含税收学)学号：X200633000