9,140 research outputs found
QCD Radiative Correction to the Hadronic Annihilation Rate of Heavy Quarkonium
Hadronic annihilation rate of heavy quarkonium is given to
next-to-leading order in and leading order in using a recently
developed factorization formalism which is based on NRQCD. The result includes
both the annihilation of P-wave color-singlet component, and the
annihilation of S-wave color-octet component of the quarkonium. The
notorious infrared divergences due to soft gluons, i.e., the Logarithms
associated with the binding energy, encountered in previous perturbative
calculations of quarkonium decays are found to be explicitly
cancelled, and a finite result for the decay width to order is
then obtained.Comment: 15 pages latex (6 figures included). In this revised version a update
reference and acknowledgement are include
Update-Efficient Regenerating Codes with Minimum Per-Node Storage
Regenerating codes provide an efficient way to recover data at failed nodes
in distributed storage systems. It has been shown that regenerating codes can
be designed to minimize the per-node storage (called MSR) or minimize the
communication overhead for regeneration (called MBR). In this work, we propose
a new encoding scheme for [n,d] error- correcting MSR codes that generalizes
our earlier work on error-correcting regenerating codes. We show that by
choosing a suitable diagonal matrix, any generator matrix of the [n,{\alpha}]
Reed-Solomon (RS) code can be integrated into the encoding matrix. Hence, MSR
codes with the least update complexity can be found. An efficient decoding
scheme is also proposed that utilizes the [n,{\alpha}] RS code to perform data
reconstruction. The proposed decoding scheme has better error correction
capability and incurs the least number of node accesses when errors are
present.Comment: Submitted to IEEE ISIT 201
Hazardous Materials Transportation with Multiple Objectives: A Case Study in Taiwan
Hazardous material (hazmat) transportation has been an important issue for handling hazardous materials, such as gases and chemical liquids. In the past, researchers have made great efforts to develop policies and route planning methods for hazmat transportation problems. In 2014, Kaohsiung City in Taiwan suffered a gas pipeline explosion at midnight; 32 people were killed, and hundreds of people were injured. After the incident, policies and routing strategies for hazardous materials (hazmat) transportation in Kaohsiung were initiated to avoid pipeline transportation. Although methodologies for hazmat transportation have been proposed and implemented to minimize potential risks, multiple objectives need to be considered in the process to facilitate hazmat transportation in Taiwan. In order to consider both government and operators’ aspects, a multi-objective formulation for the hazmat problem is proposed and a compromise programming method is applied to solve the problem with two objectives: travel cost and risk. The path risk is defined based on risk assessment indexes, such as road characteristics, population distribution, link length, hazardous material characteristics, and accident rates. An aggregate risk indicator is proposed for roadway segments. The compromise programming approach is developed from the concept of compromise decision and the main idea is to search the compromise solution closest to the ideal solution. The proposed method is applied to Kaohsiung City, Taiwan. The results show that two conflicting objectives keep making trade-offs between each other until they finally reach a compromise solution
X(3872) and its production at hadron colliders
We evaluate the production cross sections of at the LHC and
Tevatron at NLO in in NRQCD by assuming that the short-distance
production proceeds dominantly through its component in our
\chi_{c1}'\mbox{-}D^0\bar{D}^{*0} mixing model for . The outcomes of
the fits to the CMS distribution can well account for the recent ATLAS
data in a much larger range of transverse momenta
(10~\mbox{GeV}), and the CDF total cross section data, and
are also consistent with the value of constrained by the -meson decay data. %It can also well
describe the behavior of the CDF data, which show a strong
%resemblance to that of the X(3872). For LHCb the predicted X(3872) total cross
section is larger than the data by a factor of 2, which is due to the problem
of the fixed-order NRQCD calculation that may not be applicable for the region
with small (p_T\sim 5 ~\mbox{GeV}) and large forward rapidity
. In comparison, the prediction of molecule production mechanism
for is inconsistent with both distributions and total cross
sections of CMS and ATLAS, and the total cross section of CDF.Comment: Version published in PRD. More explanations added for the LHCb data.
More references added for recent experimental and theoretical results: the
ATLAS measurement on the X(3872) pT distribution in 10-70 GeV; the LHCb
measurement on the X(3872) radiative decays; the lattice calculation on
X(3872); the small resummation method, etc. No changes for the calculated
result and the conclusio
Modeling Autoregressive Models in Cool Island Effects associated with Remote Telemeter Technology (ASTER) in Taiwan: A GIS Approach
AbstractA microclimate is the unique climate of a small-scale region, such as a field or parts of urban or rural areas. The weather variables in a microclimate include temperature, wind, humidity, land forms, and water regimes. In Northern Taiwan's Taoyuan County, irrigation ponds take a long time to heat up during the summer months, keeping these rural areas cooler than surrounding urbanized areas. Based on Geographic Information System (GIS) layers associated with Digital Terrain Modeling (DTM), along with Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images, this paper examines temperature variables in four counties/cities in Taiwan for the past century. Urban development is found to have contributed to temperature increases, but an understanding of the cooling mechanism is still incomplete. Temperatures in the Taoyuan tableland have declined, at odds with trends in other areas in Taiwan as well as on a global scale. In Taoyuan, the Times-Series Regression Model was used to extrapolated a downward trend from a mean current temperature of 21.3°C currently down to 19.72°C in 2099, assuming the area of irrigation ponds remain unchanged
Applications of circularly polarized crossed dipole antennas
© 2014 IEEE. Circularly polarized crossed dipole antennas are presented in this paper. A compact crossed dipole is realized with the use of a meander line and a barbed end in each dipole arm. A vacant-quarter printed ring is used as a 90° phase delay line to achieve circularly polarized radiation. For multi-band applications, each dipole arm is divided into multi-branches with different lengths to obtain multiple resonances. These radiators can be equipped with different reflectors, such as a finite planar metallic conductor, a cavity-backed metallic conductor, and a finite artificial magnetic conductor to obtain the desired antenna radiation characteristics. These antennas are quite practical for many wireless communication systems, such as satellite communications, global positioning systems, wireless local area networks, and radio-frequency identification devices
Synergy between intention recognition and commitments in cooperation dilemmas
Commitments have been shown to promote cooperation if, on the one hand, they can be sufficiently enforced, and on the other hand, the cost of arranging them is justified with respect to the benefits of cooperation. When either of these constraints is not met it leads to the prevalence of commitment free-riders, such as those who commit only when someone else pays to arrange the commitments. Here, we show how intention recognition may circumvent such weakness of costly commitments. We describe an evolutionary model, in the context of the one-shot Prisoner's Dilemma, showing that if players first predict the intentions of their co-player and propose a commitment only when they are not confident enough about their prediction, the chances of reaching mutual cooperation are largely enhanced. We find that an advantageous synergy between intention recognition and costly commitments depends strongly on the confidence and accuracy of intention recognition. In general, we observe an intermediate level of confidence threshold leading to the highest evolutionary advantage, showing that neither unconditional use of commitment nor intention recognition can perform optimally. Rather, our results show that arranging commitments is not always desirable, but that they may be also unavoidable depending on the strength of the dilemma.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Text difficulty in extensive reading: Reading comprehension and reading motivation
This study investigates the effects of the text difficulty of extensive reading materials on the reading comprehension and reading motivation of English as a foreign language (EFL) vocational high school students in Taiwan. Two experimental groups were assigned, on an individual basis, to read graded readers at either one level below (‘i-1’) or one level beyond (‘i+1’) their current level, while a control group followed their regular curriculum. The results showed that after treatment, the ‘i-1’ group improved their overall comprehension and the subset of literal comprehension. They also outperformed the ‘i+1’ group on the same measures. For reading motivation, the ‘i+1’ group’s overall motivation was promoted. Both groups enhanced their reading engagement, while only the ‘i-1’ group inhibited reading avoidance. Moreover, the ‘i+1’ group outperformed the ‘i-1’ group in the perception of self-efficacy. Overall, the ‘i-1’ level yielded better effects on reading comprehension; the ‘i+1’ level, on reading motivation
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