109 research outputs found
TiLA: Twin-in-the-Loop Architecture for Cyber-Physical Production Systems
Digital twin is a virtual replica of a real-world object that lives
simultaneously with its physical counterpart. Since its first introduction in
2003 by Grieves, digital twin has gained momentum in a wide range of
applications such as industrial manufacturing, automotive and artificial
intelligence. However, many digital-twin-related approaches, found in
industries as well as literature, mainly focus on modelling individual physical
things with high-fidelity methods with limited scalability. In this paper, we
introduce a digital-twin architecture called TiLA (Twin-in-the-Loop
Architecture). TiLA employs heterogeneous models and online data to create a
digital twin, which follows a Globally Asynchronous Locally Synchronous (GALS)
model of computation. It facilitates the creation of a scalable digital twin
with different levels of modelling abstraction as well as giving GALS formalism
for execution strategy. Furthermore, TiLA provides facilities to develop
applications around the twin as well as an interface to synchronise the twin
with the physical system through an industrial communication protocol. A
digital twin for a manufacturing line has been developed as a case study using
TiLA. It demonstrates the use of digital twin models together with online data
for monitoring and analysing failures in the physical system
Online Cycle Detection for Models with Mode-Dependent Input and Output Dependencies
In the fields of co-simulation and component-based modelling, designers
import models as building blocks to create a composite model that provides more
complex functionalities. Modelling tools perform instantaneous cycle detection
(ICD) on the composite models having feedback loops to reject the models if the
loops are mathematically unsound and to improve simulation performance. In this
case, the analysis relies heavily on the availability of dependency information
from the imported models. However, the cycle detection problem becomes harder
when the model's input to output dependencies are mode-dependent, i.e. changes
for certain events generated internally or externally as inputs. The number of
possible modes created by composing such models increases significantly and
unknown factors such as environmental inputs make the offline (statical) ICD a
difficult task. In this paper, an online ICD method is introduced to address
this issue for the models used in cyber-physical systems. The method utilises
an oracle as a central source of information that can answer whether the
individual models can make mode transition without creating instantaneous
cycles. The oracle utilises three types of data-structures created offline that
are adaptively chosen during online (runtime) depending on the frequency as
well as the number of models that make mode transitions. During the analysis,
the models used online are stalled from running, resulting in the discrepancy
with the physical system. The objective is to detect an absence of the
instantaneous cycle while minimising the stall time of the model simulation
that is induced from the analysis. The benchmark results show that our method
is an adequate alternative to the offline analysis methods and significantly
reduces the analysis time.Comment: \c{opyright} 2021. This manuscript version is made available under
the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0
Enhancement of Biological Activated Carbon (BAC) Process to Improve Removal Efficiency of Micropollutants
Objectives In this study, the removal efficiency of micropollutants in the biological activated carbon (BAC) process was investigated, and a method for improving the removal efficiency of micropollutants in the BAC process of water treatment plants was proposed. Methods Dibromo-methylparaben (Br2-MP) was selected as the target micropollutant. Batch and lab-scale column experiments were conducted to evaluate the removal efficiencies of Br2-MP in the conventional BAC process and the BAC with enhanced biofilm properties by the addition of phosphorus (P) and hydrogen peroxide (H2O2). Biodegradation kinetics were evaluated using results from batch and lab scale column experiments. Results and Discussion As a result of comparing the removal efficiency of Br2-MP in a batch experiment with the same biomass concentrations (2.0±0.2×107 cells), the biodegradation rate constant (kbio) of the enhanced BAC process was found to be 1.2 times higher than that of the conventional BAC process due to its higher biological activity (enhanced BAC: 3.4±0.3 mg·C/g·hr, conventional BAC: 2.9±0.4 mg·C/g·hr). Comparison of removal efficiencies of Br2-MP in batch experiments with the same wet weight of BAC (1 g) showed that the biodegradation rate constant (kbio) of the enhanced BAC process was 1.9 times higher than that of conventional BAC process due to higher biomass (enhanced BAC: 3.5±0.4 µg·ATP/g·GAC, conventional BAC: 2.3±0.2 µg·ATP/g·GAC). Through the batch experiments, the enhanced BAC process was efficient in removing Br2-MP via increasing both biomass concentrations and activity of attached microorganisms. Lab-scale column experiments conducted under different water temperatures (5 and 25℃) and empty bed contact time (EBCT: 5-40 min) conditions showed higher removal efficiency of Br2-MP in the enhanced BAC process than the conventional BAC process throughout the entire period of operation. In particular, the removal efficiency of Br2-MP between the enhanced and conventional BAC processes showed significant differences at low temperature (5℃) and short EBCT (5 min). At 5℃ and 25℃, the kbio of the conventional BAC process was 0.0229 min-1 and 0.0612 min-1, respectively, and the kbio of the enhanced BAC process was 0.0470 min-1 and 0.1421 min-1, respectively, These results showed that the enhanced BAC process had two times higher biodegradability of Br2-MP than the conventional BAC process. These results showed a similar trend to the results from the batch experiment. In an experiments simulating the impact of frequent EBCT changes during summer, the enhanced BAC process maintained a relatively stable removal efficiency of Br2-MP compared to the conventional BAC process. Conclusion The enhanced BAC process showed superior biodegradation of micropollutant compared to the conventional BAC process. Considering economic costs (e.g., costs of adding phosphate and hydrogen peroxide) and water quality, it appears to be an efficient alternative to operate the enhanced BAC process intermittently, limited to cases where EBCT is shortened, such as summer, or when water temperature is low, such as in winter
Observation of Cabibbo-suppressed and W-exchange Lambda_c^+ baryon decays
We present measurements of the Cabibbo-suppressed decays Lambda_c^+ -->
Lambda0 K+ and Lambda_c^+ --> Sigma0 K+ (both first observations), Lambda_c^+
--> Sigma+ K+ pi- (seen with large statistics for the first time), Lambda_c^+
--> p K+ K- and Lambda_c^+ --> p phi (measured with improved accuracy).
Improved branching ratio measurements for the decays Lambda_c^+ --> Sigma+ K+
K- and Lambda_c^+ --> Sigma+ phi, which are attributed to W-exchange diagrams,
are shown. We also present the first evidence for Lambda_c^+ --> Xi(1690)^0 K+
and set an upper limit on the non-resonant decay Lambda_c^+ --> Sigma+ K+ K-.
This analysis was performed using 32.6 fb^{-1} of data collected by the Belle
detector at the asymmetric e+ e- collider KEKB.Comment: Submitted to Phys. Lett. B. v2: A small correction to the Authorlist
was made. An earlier version of this analysis was released as
BELLE-CONF-0130, hep-ex/010800
Measurement of Branching Fractions for Decays
We report measurements of branching fractions for charged and neutral decays where the meson is reconstructed in the and decay
channels. The neutral channel is a CP eigenstate and can be used to
measure the CP violation parameter . We also report the first
observation of the mode. The results are based on an
analysis of 29.1 fb of data collected by the Belle detector at KEKB.Comment: To appear in Physical Review Letter
Determination of |Vcb| using the semileptonic decay \bar{B}^0 --> D^{*+}e^-\bar{\nu}
We present a measurement of the Cabibbo-Kobayashi-Maskawa (CKM) matrix
element |Vcb| using a 10.2 fb^{-1} data sample recorded at the \Upsilon(4S)
resonance with the Belle detector at the KEKB asymmetric e^+e^- storage ring.
By extrapolating the differential decay width of the \bar{B}^0 -->
D^{*+}e^-\bar{\nu} decay to the kinematic limit at which the D^{*+} is at rest
with respect to the \bar{B}^0, we extract the product of |Vcb| with the
normalization of the decay form factor F(1), |Vcb |F(1)=
(3.54+/-0.19+/-0.18)x10^{-2}, where the first error is statistical and the
second is systematic. A value of |Vcb| = (3.88+/-0.21+/-0.20+/-0.19)x10^{-2} is
obtained using a theoretical calculation of F(1), where the third error is due
to the theoretical uncertainty in the value of F(1). The branching fraction
B(\bar{B}^0 --> D^{*+}e^-\bar{\nu}) is measured to be
(4.59+/-0.23+/-0.40)x10^{-2}.Comment: 20 pages, 6 figures, elsart.cls, submitted to PL
Study of Exclusive B decays to Charmed Baryons
Using 29.1fb-1 of data accumulated at the Upsilon(4S) with the Belle detector
at KEKB, we have studied the decay modes B0bar->Lambda_c+ pbar pi+pi-, B- ->
Lambda_c+ pbar pi-, and B0bar ->Lambda_c+ pbar. We report branching fractions
of exclusive B decays to charmed baryons with four-, three- and two-body final
states, including intermediate Sigma_c++ and Sigma_c0 states. We observed B0bar
-> Sigma_c(2455)++pbar pi- for the first time with a branching fraction of
(2.38+0.63-0.55+-0.41+-0.62)x10-4 and observed evidence for the two-body decay
B- ->Sigma_c(2455)0 pbar with a branching fraction of
(0.45+0.26-0.19+-0.07+-0.12)x10-4. We also set improved upper limits for the
two-body decays B0bar -> Lambda_c+ pbar and B- -> Sigma_c(2520)0 pbar.Comment: accepted for publication in Phys. Rev.
Measurements of Branching Fractions and Decay Amplitudes in B-> J/\psi K^* decays
The branching fractions and the decay amplitudes of B -> J/psi K^* decays are
measured in a 29.4/fb data sample collected with the Belle detector at the KEKB
electron-positron collider. The decay amplitudes of helicity states of the
J/psi K^* system are determined from the full angular distribution of the final
state particles in the transversity basis. The branching fractions are measured
to be (1.29\pm0.05\pm0.13) \times 10^{-3} for neutral mesons and
(1.28\pm0.07\pm0.14) \times 10^{-3} for charged mesons. The measured
longitudinal and transverse (perpendicular to the transversity plane)
amplitudes are |A_0|^2 = 0.62\pm0.02\pm0.03 and |A_{\perp}|^2 =
0.19\pm0.02\pm0.03, respectively. The value of |A_{\perp}|^2 shows that the CP
even component dominates in the B^0 \to J/\psi K^{*0}(K_S\pi^0) decay.Comment: 17 pages, 3 figures, 5 tables, to appear in Phys. Lett.
Observation of chi_c2 Production in B-meson Decay
We report the first observation of chi_c2 production in B-meson decays. We
find an inclusive B -> chi_c2 X branching fraction of (1.80^{+0.23}_{-0.28}+/-
0.26) 10^-3. The data set, collected with the Belle detector at the KEKB e^+e^-
collider, consists of 31.9 million B\bar B events. We also present branching
fractions and momentum spectra for both chi_c1 and chi_c2 production.Comment: 5 pages with 2 figure
A Measurement of Lifetime Difference in Meson Decays
We report a measurement of the - mixing parameter
using 23.4 fb of data collected near the (4S) resonance with
the Belle detector at KEKB. is measured from the lifetime difference
of mesons decaying into the state and the CP even eigenstate
. We find , where
the first error is statistical and the second systematic, corresponding to a
95% confidence interval .Comment: 10 pages, 3 figure
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