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Chen Gang

Publications and source records attributed to Chen Gang.

17 recordsLinked to original sources

MorphingDB: A Task-Centric AI-Native DBMS for Model Management and Inference

The increasing demand for deep neural inference within database environments has driven the emergence of AI-native DBMSs. However, existing solutions either rely on model-centric designs requiring developers to manually select, configure, and maintain models, resulting in high development overhead, or adopt task-centric AutoML approaches with high computational costs and poor DBMS integration. We present MorphingDB, a task-centric AI-native DBMS that automates model storage, selection, and inference within PostgreSQL. To enable flexible, I/O-efficient storage of deep learning models, we first introduce specialized schemas and multi-dimensional tensor data types to support BLOB-based all-in-one and decoupled model storage. Then we design a transfer learning framework for model selection in two phases, which builds a transferability subspace via offline embedding of historical tasks and employs online projection through feature-aware mapping for real-time tasks. To further optimize inference throughput, we propose pre-embedding with vectoring sharing to eliminate redundant computations and DAG-based batch pipelines with cost-aware scheduling to minimize the inference time. Implemented as a PostgreSQL extension with LibTorch, MorphingDB outperforms AI-native DBMSs (EvaDB, Madlib, GaussML) and AutoML platforms (AutoGluon, AutoKeras, AutoSklearn) across nine public datasets, encompassing series, NLP, and image tasks. Our evaluation demonstrates a robust balance among accuracy, resource consumption, and time cost in model selection and significant gains in throughput and resource efficiency.

cs.DB

Blockchain Goes Green? Part II: Characterizing the Performance and Cost of Blockchains on the Cloud and at the Edge

While state-of-the-art permissioned blockchains can achieve thousands of transactions per second on commodity hardware with x86/64 architecture, their performance when running on different architectures is not clear. The goal of this work is to characterize the performance and cost of permissioned blockchains on different hardware systems, which is important as diverse application domains are adopting t. To this end, we conduct extensive cost and performance evaluation of two permissioned blockchains, namely Hyperledger Fabric and ConsenSys Quorum, on five different types of hardware covering both x86/64 and ARM architecture, as well as, both cloud and edge computing. The hardware nodes include servers with Intel Xeon CPU, servers with ARM-based Amazon Graviton CPU, and edge devices with ARM-based CPU. Our results reveal a diverse profile of the two blockchains across different settings, demonstrating the impact of hardware choices on the overall performance and cost. We find that Graviton servers outperform Xeon servers in many settings, due to their powerful CPU and high memory bandwidth. Edge devices with ARM architecture, on the other hand, exhibit low performance. When comparing the cloud with the edge, we show that the cost of the latter is much smaller in the long run if manpower cost is not considered.

cs.DC

Light (anti)nuclei production in Cu+Cu collisions at $\sqrt{s_{\rm{NN}}}=200$GeV

The production of light (anti)nuclei have been investigated using the dynamically constrained phase-space coalescence model based on the final-state hadrons generated by the PACIAE model in Cu+Cu collisions at $\sqrt{s_{\rm{NN}}}=200$GeV with $|η|<0.5$ and $0<p_T<8$GeV/c. The results show that there is a strong centrality dependence of yields of $\rm d$, $\rm\overline d$, $\rm ^3He$, $\rm^3\overline {He}$, $\rm ^4He$, and $\rm^4\overline {He}$, i.e., their yields decrease rapidly with the increase of centrality, and the greater the mass is, the greater the dependence shows; whereas their ratio of antinucleus to nucleus and coalescence parameter $B_A$ remain constant as the centrality increases. In addition, the yields of (anti)nuclei are strongly dependent on the mass of the (anti)nuclei, indicating that the (anti)nuclei produced have mass scaling properties in high-energy heavy-ion collisions. Our results are consistent with the STAR experimental data.

nucl-th

Effective Scheduling Function Design in SDN through Deep Reinforcement Learning

Recent research on Software-Defined Networking (SDN) strongly promotes the adoption of distributed controller architectures. To achieve high network performance, designing a scheduling function (SF) to properly dispatch requests from each switch to suitable controllers becomes critical. However, existing literature tends to design the SF targeted at specific network settings. In this paper, a reinforcement-learning-based (RL) approach is proposed with the aim to automatically learn a general, effective, and efficient SF. In particular, a new dispatching system is introduced in which the SF is represented as a neural network that determines the priority of each controller. Based on the priorities, a controller is selected using our proposed probability selection scheme to balance the trade-off between exploration and exploitation during learning. In order to train a general SF, we first formulate the scheduling function design problem as an RL problem. Then a new training approach is developed based on a state-of-the-art deep RL algorithm. Our simulation results show that our RL approach can rapidly design (or learn) SFs with optimal performance. Apart from that, the trained SF can generalize well and outperforms commonly used scheduling heuristics under various network settings.

cs.LG

Study on Fractal Characteristics in the e$^+$e$^-$ Collisions at $\sqrt{s_{NN}}=250$GeV

The fractal characteristics of multi-particle final state are first studied in the $e^+e^-$ collision of $\sqrt{s_{NN}}=250$GeV, with the MC simulation generator Jetset7.4 and Herwig5.9. The result is shown that this multi-particle final state is self-affine fractal, and exists a double-Hurst-exponent phenomenon. Their fractal indices and the effective fluctuation strength are also predicted.

hep-ph

Scaling properties of multiplicity fluctuations in heavy ion collisions simulated by AMPT model

Three-dimensional, as well as one- and two-dimensional, studies of multiplicity fluctuation are performed using AMPT model to generate central Au-Au collision events at ${\sqrt s_{NN}}= 200$ GeV. Two- and three-dimensional normalized factorial moments in rapidity, transverse momentum and azimuthal angle are found to exhibit power-low scaling when partitioning with the same number of bins in each direction, indicating that the fluctuation are isotropic, i.e. the fractality is self-similar in multiparticle production of central Au-Au collisions. Further, we measured the parameter $ν$ which it characterizes the intermittency indices derived in particular analysis. It is found that our model result ${ν_{yϕp_t}}= 1.86{\pm}0.07$ is larger than $ν = 1.304$,which is the value of Ginzburg-Landau type of phase transition. We also explored the intermittent or fluctuational dependence on the transverse momentum. The result shows that the intermittency or fluctuation increase rapidly with the increasing of transverse momentum.

nucl-th

Analysis of the Optimal Resource Allocation for a Tandem Queueing System

In this paper, we study a controllable tandem queueing system consisting of two nodes and a controller, in which customers arrive according to a Poisson process and must receive service at both nodes before leaving the system. A decision maker dynamically allocates the number of service resource to each node facility according to the number of customers in each node. In the model, the objective is to minimize the long-run average costs. We cast these problems as Markov decision problems by dynamic programming approach and derive the monotonicity of the optimal allocation policy and the relationship between the two nodes' optimal policy. Furthermore, we get the conditions under which the optimal policy is unique and has the bang-bang control policy property.

math.PR

Study on the Energy Dependence of the Radii of Jets by the HBT Correlation Method in e+e- collisions

The energy dependence of the radii size of jets are studied in detail by the HBT correlation method using Monte Carlo Simulation generator Jetset7.4 to produce 40,000,000 events of e$^+$e$^-$ collisions at $\sqrt s =30$, 50, 70, 91.2, 110, 130, 150 and 170 GeV. The radii of jets are measured using the HBT correlation method with the indistinguishability of identical final state pions. It is found that the average radii of quark-jets and gluon-jets are independent of the c.m. energy of e$^+$e$^-$ collisions. The average radius of quark-jets are obviously larger than that of gluon-jets. The invariable average radii of quark-jets and gluon-jets in e$^+$e$^-$ collisions are obtained at the end of parton evolvement.

hep-ph

Eccentricity and elliptic flow at fixed centrality in Au+Au collisions at sqrt(s_NN)=200GeV in AMPT

To reduce the effect of the fluctuations of initial geometrical shape, elliptic flow are studied at fixed centrality in Au+Au collision at $\sqrt{s_{\rm NN}}$=200GeV. It is observed with the participant increasing, elliptic flow has an increase and a decrease at different fixed impact parameter, but not a trivial fluctuation. It is analyzed that the initial space anisotropy dominates the participant dependence of elliptic flow in near-central collisions(b=5fm) and mid-central collisions(b=8fm), while the interaction between particles can mainly answer for the behavior of elliptic flow in peripheral collisions(b=12fm). To distinguish the pure geometrical effect, elliptic flow scaled by initial eccentricity is studied. It is found that the ratio $v_{2}/ε$ increases with participant and reaches a saturation when the participant is large enough, indicating that the collision system reach the local equilibrium.

nucl-th

Study on the method of mini-jet identification in relativistic heavy ion collisions

In this thesis a set of methods identifying minijet from final state particles in the relativistic heavy ion collision events is established and the parameter dependence has been investigated in Au+Au collisions at $\sqrt s= 200$GeV using a multiphase transport model (AMPT). It is found that the number of minijets reduces with the increasing of collision parameter and raises with the increasing of c.m energy. Furthermore, we analyze the rapidity and momentum distribution inside minijets identified using this method.

hep-ph

A Monte Carlo study on the production scale and internal structure of jets in high energy collisions

The production scale and internal structure of jets produced in high energy collisions are studied using Jetset7.4 and Herwig5.9 Monte Carlo generators. Two scales are found. One is the jet-development scale, which determines the size of the jet developed from a mother-parton. The other one is the jet-production scale, the jets produced with this scale are the most consistent with QCD jet-production dynamics and will provide the most reliable dynamical information about their mother-partons.

hep-ph

A Monte Carlo Study of the Levy Stability and Multifractal Spectrum in e+e- collisions

The Levy stability analysis is carried out for e+e- collisions at Z^0 mass using Monte Carlo method. The Levy index μis found to be μ=1.701 +- 0.043. The self-similar generalized dimensions D(q) and multi-fractal spectrum f(α) are presented. The Renyi dimension D(q) decreases with increasing q. The self-similar multi-fractal spectrum is a convex curve with a maximum at q = 0, α= 1.169 +- 0.011. The right-side part of the spectrum, corresponding to negative values of q is obtained through analytical continuation.

hep-ph

A Monte Carlo Study on the Dynamical Fluctuations Inside Quark and Antiquark Jets

The dynamical fluctuations inside the quark and antiquark jets are studied using Monte Carlo method. Quark and antiquark jets are identified from the 2-jet events in e+e- collisions at 91.2 GeV by checking them at parton level. It is found that transition point exists inside both of these two kinds of jets. At this point the jets are circular in the transverse plane with respect to the property of dynamical fluctuations. The results are consistent with the fact that the third jet (gluon jet) was historically first discovered in e+e- collisions in the energy region 17-30 GeV.

hep-ph

On the Scale of Visible Jets in High Energy Electron-Positron Collisions

A study of the dynamical fluctuation property of jets is carried out using the Monte Carlo method. The results suggest that, the anisotropy of dynamical fluctuations in the hadronic system inside jets, changes abruptly with the variation of the cut parameter y_cut. A transition point exists, where these fluctuations behave like those in soft hadronic collisions, i.e. being circular in the transverse plane with respect to dynamical fluctuations.

hep-ph

A Monte Carlo Study of the Dynamical-Flucautation Property of the Hadronic System Inside Jets

A study of the dynamical fluctuation property of jets is carried out using Monte Carlo method. The results suggest that, unlike the average properties of the hadronic system inside jets, the anisotropy of dynamical fluctuations in these systems changes abruptly with the variation of the cut parameter $\yct$. A transition point exists, where the dynamical fluctuations in the hadronic system inside jet behave like those in soft hadronic collisions, i.e. being circular in the transverse plan with repect to dynamical fluctuations. This finding obtained from Jetset and Herwig Monte Carlo is encouraged to be checked by experiments.

hep-ph

On the Factorial Moment Analysis of High Energy Experimental Data with Non-integer Partition Number

It is pointed out that in doing the factorial moment analysis with non-integer partition $M$ of phase space, the influence of the phase-space variation of two- (or more-) particle correlations has to be considered carefully. In this paper this problem is studied and a systematic method is developed to minimize this influence. The efficiency and self-consistency of this method are shown using the data of 250 GeV/$c$ $π^+$p and K$^+$p collisions from the NA22 experiment as example.

hep-ph