arXiv subjects

Chao Guo

Publications and source records attributed to Chao Guo.

23 records · Page 2Linked to original sources

arXiv2019

Temperature-Aware Virtual Data Center Embedding to Avoid Hot Spots in Data Centers

Virtual Data Center (VDC) embedding has drawn significant attention recently because of growing need for efficient and flexible means of Data Center (DC) resource allocation. Existing studies on VDC embedding mainly focus on improving DCs' resource utilization. However, an important problem that has not been considered in VDC embedding solutions is the creation of hot spots by excessive heat dissipation and hot air generation from racks in DCs, which have significant adverse effect on energy consumption of the cooling system and IT equipment lifespan. To address this issue, we propose a temperature-aware VDC embedding scheme to avoid hot spots by minimizing the maximum temperature of hot air emitted from each rack. Meanwhile, we also aim to reduce the total power consumption of IT equipment in this scheme. A Mixed Integer Linear Programming (MILP) model and a heuristic algorithm are developed to implement the proposed VDC embedding scheme. Numerical results show that the proposed temperature-aware embedding scheme can significantly outperforms a load-balanced embedding scheme in terms of maximum rack temperature, total power consumption of IT equipment, and VDC rejection ratio.

cs.NI↗

arXiv2019

Dark matter and LHC phenomenology of a scale invariant scotogenic model

We study the phenomenology of a model that addresses the neutrino mass, dark matter, and generation of the electroweak scale in a single framework. Electroweak symmetry breaking is realized via the Coleman-Weinberg mechanism in a classically scale invariant theory, while the neutrino mass is generated radiatively through interactions with dark matter in a typically scotogenic manner. The model introduces a scalar triplet and singlet and a vector-like fermion doublet that carry an odd parity of $Z_2$, and an even parity scalar singlet that helps preserve classical scale invariance. We sample over the parameter space by taking into account various experimental constraints from the dark matter relic density and direct detection, direct scalar searches, neutrino mass, and charged lepton flavor violating decays. We then examine by detailed simulations possible signatures at the LHC to find some benchmark points of the free parameters. We find that the future high-luminosity LHC will have a significant potential in detecting new physics signals in the dilepton channel.

hep-ph↗

arXiv2017

The process of 3D-printed skull models for the anatomy education

Objective The 3D printed medical models can come from virtual digital resources, like CT scanning. Nevertheless, the accuracy of CT scanning technology is limited, which is 1mm. In this situation, the collected data is not exactly the same as the real structure and there might be some errors causing the print to fail. This study presents a common and practical way to process the skull data to make the structures correctly. And then we make a skull model through 3D printing technology, which is useful for medical students to understand the complex structure of skull. Materials and Methods The skull data is collected by the CT scan. To get a corrected medical model, the computer-assisted image processing goes with the combination of five 3D manipulation tools: Mimics, 3ds Max, Geomagic, Mudbox and Meshmixer, to reconstruct the digital model and repair it. Subsequently, we utilize a low-cost desktop 3D printer, Ultimaker2, with polylactide filament (PLA) material to print the model and paint it based on the atlas. Result After the restoration and repairing, we eliminate the errors and repair the model by adding the missing parts of the uploaded data within 6 hours. Then we print it and compare the model with the cadaveric skull from frontal, left, right and anterior views respectively. The printed model can show the same structures and also the details of the skull clearly and is a good alternative of the cadaveric skull.

cs.OH↗

arXiv2017

Hunting for Heavy Majorana Neutrinos with Lepton Number Violating Signatures at LHC

The neutrinophilic two-Higgs-doublet model ($ν$2HDM) provides a natural way to generate tiny neutrino mass from interactions with the new doublet scalar $Φ_ν$ ($H^\pm,~H,~A$) and singlet neutrinos $N_R$ of TeV scale. In this paper, we perform detailed simulations for the lepton number violating (LNV) signatures at LHC arising from cascade decays of the new scalars and neutrinos with the mass order $m_{N_R}<m_{Φ_ν}$. Under constraints from lepton flavor violating processes and direct collider searches, their decay properties are explored and lead to three types of LNV signatures: $2\ell^\pm 4j+\cancel{E}_T$, $3\ell^\pm 4j+\cancel{E}_T$, and $3\ell^\pm\ell^\mp 4j$. We find that the same-sign trilepton signature $3\ell^\pm4j+\cancel{E}_T$ is quite unique and is the most promising discovery channel at the high-luminosity LHC. Our analysis also yields the $95\%$ C.L. exclusion limits in the plane of the $Φ_ν$ and $N_R$ masses at 13 (14) TeV LHC with an integrated luminosity of 100~(3000)/fb.

hep-ph↗

arXiv2012

Social Media and the Social Good: How Nonprofits Use Facebook to Communicate with the Public

In this study, we examine the social networking practices of the 100 largest nonprofit organizations in the United States. More specifically, we develop a comprehensive classification scheme to delineate these organizations' use of Facebook as a stakeholder engagement tool. We find that there are 5 primary categories of Facebook "statuses", which can be aggregated into three key dimensions - "information", "community", and "action". Our analysis reveals that, though the "informational" use of Facebook is still significant, nonprofit organizations are better at using Facebook to strategically engage their stakeholders via "dialogic" and "community-building" practices than they have been with traditional websites. The adoption of social media seems to have engendered new paradigms of public engagement.

cs.CY↗