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An adaptive sequential experiment design method for model validation

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Chinese Journal of Aeronautics 2020年第6期33卷 1661-1672页

作者： Ke FANG Yuchen ZHOU Ping MA Control and Simulation Center Harbin Institute of TechnologyHarbin 150080China

Efficient experiment design is of great significance for the validation of simulation model with high nonlinearity and large input space.Excessive validation experiment raises the cost while insufficient test increases the risks of accepting an invalid model.In this paper,an adaptive sequential experiment design method combining global exploration criterion and local exploitation criterion is proposed.The exploration criterion utilizes discrepancy metric to improve the space-filling property of the design points while the exploitation criterion employs the leave one out error to discover informative points.To avoid the clustering of samples in the local region,an adaptive weight updating approach is provided to maintain the balance between exploration and exploitation.Besides,the credibility distribution function characterizing the relationship between the input and result credibility is introduced to support the model validation experiment design.Finally,six benchmark problems and an engineering case are applied to examine the performance of the proposed method.The experiments indicate that the proposed method achieves satisfactory performance for function approximation in accuracy and convergence.

关键词： Adaptive sequential experiment design Credibility distribution function Gaussian process model Metamodeling Model validation

A CRISPR-Cas9 screen shows the combination efficacy of lenvatinib plus epidermal growth factor receptor inhibitors for treatment of liver cancer

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Cancer Biology & Medicine 2022年第2期19卷 136-139页

作者： yuchen Guo Yangyang zhou Wenxin Qin State Key Laboratory of Oncogenes and Related Genes Shanghai Cancer InstituteRenji HospitalShanghai Jiao Tong University School of MedicineShanghai 200032China

Recently,in cooperation with the Netherlands Cancer Institute,we demonstrated that epidermal growth factor receptor(EGFR)activation limited the response of liver cancer to lenvatinib.The original article was published in Nature as a cover story,which resulted in considerable attention from major scientific journals.Here,we were invited by Cancer Biology&Medicine to provide comments on preclinical and clinical findings about the combination of lenvatinib plus EGFR inhibitors as a promising strategy for hepatocellular carcinoma(HCC)treatment.Primary liver cancer represents the sixth most common malignancy and the third leading cause of cancer-related mortality worldwide,with an estimated 906,000 new cases and 830,000 deaths in 20201.

关键词： treatment finding inhibitors

Secure coordinated direct and untrusted relay transmissions via interference engineering

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Science China(Information Sciences) 2022年第8期65卷 213-227页

作者： Lu LV Zan LI Haiyang DING Yuchen ZHOU Jian CHEN State Key Laboratory of Integrated Services Networks Xidian University National Mobile Communications Research Laboratory Southeast University School of Information and Communications National University of Defense Technology

This paper investigates the physical layer security issue of the coordinated direct and untrusted relay transmissions, considering both uplink and downlink scenarios. To effectively prevent the untrusted relay from eavesdropping on the confidential information it receives, two novel interference-assisted jamming schemes are proposed, where the inter-user interference and the artificial noise are intelligently engineered to degrade the signal reception quality at the untrusted relay, therefore enhancing the physical layer security for the uplink and downlink coordinated transmission, respectively. For each of the two proposed jamming schemes, a lower bound for the ergodic secrecy sum rate(ESSR) is derived in closed form to evaluate the secrecy performance. To obtain more system design insights, we further provide an asymptotic analysis for the ESSR scaling laws over the regimes of the high signal-to-noise ratio and a large number of antennas at the base-station. We carry out computer simulations to confirm the accuracy of the derived theoretical analysis.Our simulation results show that the proposed jamming schemes achieve a similar asymptotic performance limit to the case of using a trusted relay. Moreover, the proposed jamming schemes guarantee perfect security for both uplink and downlink coordinated transmissions, and yield a significant ESSR improvement compared with three other baseline schemes.

关键词： physical layer security untrusted relay interference exploitation coordinated transmission ergodic secrecy rate

Attention-Enhanced Voice Portrait Model Using GenerativeAdversarial Network

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Computers, Materials & Continua 2024年第4期79卷 837-855页

作者： Jingyi Mao Yuchen ZHOU YifanWang Junyu Li Ziqing Liu Fanliang Bu School of Information Network Security People’s Public Security University of ChinaBeijing100038China

Voice portrait technology has explored and established the relationship between speakers’ voices and their facialfeatures, aiming to generate corresponding facial characteristics by providing the voice of an unknown speaker.Due to its powerful advantages in image generation, Generative Adversarial Networks (GANs) have now beenwidely applied across various fields. The existing Voice2Face methods for voice portraits are primarily based onGANs trained on voice-face paired datasets. However, voice portrait models solely constructed on GANs facelimitations in image generation quality and struggle to maintain facial similarity. Additionally, the training processis relatively unstable, thereby affecting the overall generative performance of the model. To overcome the abovechallenges,wepropose a novel deepGenerativeAdversarialNetworkmodel for audio-visual synthesis, namedAVPGAN(Attention-enhanced Voice Portrait Model using Generative Adversarial Network). This model is based ona convolutional attention mechanism and is capable of generating corresponding facial images from the voice ofan unknown speaker. Firstly, to address the issue of training instability, we integrate convolutional neural networkswith deep GANs. In the network architecture, we apply spectral normalization to constrain the variation of thediscriminator, preventing issues such as mode collapse. Secondly, to enhance the model’s ability to extract relevantfeatures between the two modalities, we propose a voice portrait model based on convolutional attention. Thismodel learns the mapping relationship between voice and facial features in a common space from both channeland spatial dimensions independently. Thirdly, to enhance the quality of generated faces, we have incorporated adegradation removal module and utilized pretrained facial GANs as facial priors to repair and enhance the clarityof the generated facial images. Experimental results demonstrate that our AVP-GAN achieved a cosine similarity of0.511, outperforming the performance of our comparison mo

关键词： Cross-modal generation GANs voice portrait technology face synthesis

Surgical treatment of pulsatile tinnitus related to the sigmoid sinus

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Journal of Otology 2023年第1期18卷 21-25页

作者： Yuxuan Xing Song Gao Yuchen ZHOU Shenghua Song Ling Lu Jie Chen Yanhong Dai Department of Otolaryngology Head and Neck Surgery Affiliated Drum Tower Hospital of Nanjing University Medical SchoolJiangsu Provincial Key Medical Discipline(Laboratory)Nanjing210008People's Republic of China Research Institute of Otolaryngology No.321 Zhongshan RoadNanjing210008People's Republic of China Department of Otolaryngology Head and Neck Surgery Drum Tower Hospital Clinical College of Nanjing Medical UniversityNanjing210008People's Republic of China

Objective: Tinnitus-a common clinical symptom-can be categorized into pulsatile tinnitus(PT) and non-PT. Among these, PT is usually associated with sigmoid sinus symptoms, such as sigmoid sinus wall defect or diverticulum, for which various surgical treatments are available. We have discussed the clinical efficacy of surgery for sigmoid sinus-associated PT via the transmastoid approach in this study.Methods: We conducted a retrospective review of 4 patients who underwent surgery for sigmoid sinusassociated PT via the transmastoid approach at Nanjing Drum Tower Hospital from January to December2020. Of these, 2 patients had sigmoid sinus wall defect and 2 had sigmoid sinus diverticulum. Postoperative tinnitus grading and surgical efficacy were determined.Results: After surgery, PT dissolved in 3 patients, while tinnitus significantly decreased in 1 patient.During the follow-up period of 12-18 months, none of the 4 patients showed complications related to increased intracranial pressure or venous sinus thrombosis, and tinnitus symptoms disappeared in 3patients without recurrence, although 1 patient occasionally developed tinnitus. Postoperative thin-slice CTA of the temporal bone indicated that the sigmoid sinus bone wall defect or diverticulum was completely repaired with a thick soft tissue coverage.Conclusion: Surgical repair of sigmoid sinus-associated PT via the transmastoid approach deserves clinical promotion as it exhibited better efficiency while being relatively less invasive.

关键词： Pulsatile tinnitus Sigmoid sinus wall defect Sigmoid sinus diverticulum Efficacy of surgery Transmastoid approach

Validation method for simulation models with cross iteration

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Journal of Systems Engineering and Electronics 2019年第3期30卷 555-563页

作者： FANG Ke ZHAO Kaibin zhou yuchen Control and Simulation Center Harbin Institute of Technology

Cross iteration often exists in the computational process of the simulation models, especially for control models. There is a credibility defect tracing problem in the validation of models with cross iteration. In order to resolve this problem, after the problem formulation, a validation theorem on the cross iteration is proposed, and the proof of the theorem is given under the cross iteration circumstance. Meanwhile, applying the proposed theorem, the credibility calculation algorithm is provided, and the solvent of the defect tracing is explained. Further, based on the validation theorem on the cross iteration, a validation method for simulation models with the cross iteration is proposed, which is illustrated by a flowchart step by step. Finally, a validation example of a sixdegree of freedom (DOF) flight vehicle model is provided, and the validation process is performed by using the validation method. The result analysis shows that the method is effective to obtain the credibility of the model and accomplish the defect tracing of the validation.

关键词： validation method simulation model cross iteration validation theorem validation example

Unveiling structural features and mechanical properties of amorphous Si_(2)BC_(3)N by density functional theory

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Journal of Materials Science & Technology 2023年第8期139卷 103-112页

作者： yuchen Liu Yu zhou Dechang Jia Zhihua Yang Daxin Li Bin Liu Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Zhejiang Laboratory Hangzhou 311100China

The atomic structural features and the mechanical properties of the Si_(2)BC_(3)N are investigated employ-ing ab-initio calculations.The chemical bonding types and their proportion are clarified.The tetrahedral and trigonal configurations,together with their nesting,are identified,which contribute to the flexibil-ity of structural characteristics.The Si-related coordination aggravates the inhomogeneous distribution of chemical bonding and weakens the tetrahedral units.The accompanying polyhedral distortion is quanti-tatively reflected by the bond length and its deviation of polyhedron units.The elastic moduli and the ideal strengths of Si_(2)BC_(3)N are found to be lower than SiC and Si_(3)N_(4),as a result of the weakening effect of coordination Si on tetrahedral units and the existence of easily distorted trigona.The balance between tetrahedral and trigonal features through composition tailor is believed an effective way for the design of Si-B-C-N ceramics for structural applications.

关键词： Amorphous SiBCN Ab-initio calculations Atomic structure Electronic structure Mechanical properties

Development levels of pediatric palliative care teams and the extent of palliative care understanding and implementation among pediatric oncologists in China

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Pediatric Investigation 2021年第4期5卷 265-270页

作者： Siyu Cai Qiaohong Guo Xianjing Wang Ruixin Wang Peiyi Yang Yuchen ZHOU Yanhui Luo Xuan zhou Xiaoxia Peng Center for Clinical Epidemiology and Evidence-based Medicine Beijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijingChina School of Nursing Capital Medical UniversityBeijingChina Department of Hematology The Third People’s Hospital of ZhengzhouHenanChina Hematology Center Beijing Key Laboratory of Pediatric Hematology OncologyNational Key Discipline of Pediatrics(Capital Medical University)Key Laboratory of Major Diseases in ChildrenMinistry of EducationBeijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijingChina Pediatric Oncology Center Beijing Children’s HospitalCapital Medical UniversityNational Center for Children’s HealthBeijingChina

Importance:Pediatric palliative care(PPC)is an interdisciplinary collaboration that focuses on the prevention and relief of patient suffering.PPC has emerged as a critical field of medical expertise and practice.However,no information is available regarding the progress of PPC in the Chinese mainland.Objective:This study investigated the geographic distribution,team structure,and services of PPC teams in the Chinese mainland.It also investigated the level of understanding and implementation among pediatric oncologists regarding PPC.Methods:The PPC subspecialty group of the Pediatrics Society of the Chinese Medical Association included 45 PPC teams.The team structure and services were investigated using questionnaires mailed to the team leader of each PPC team.In addition,we sent questionnaires regarding the level of PPC understanding and implementation of PPC practices to 170 pediatric oncologists in 11 hospitals.Results:The geographical distribution of PPC teams is uneven in China.Most PPC teams are concentrated in the eastern provincial capital of China.Most PPC teams had limited staff and services.The level of PPC understanding was considerably limited across all demographics;most pediatric oncologists reported“some understanding”(n=71,41.8%)or“poor understanding”(n=50,29.4%).Only 62.9%of pediatric oncologists had experience providing advice to family members regarding PPC matters.Interpretation:China is currently experiencing a critical shortage of PPC resources.Most pediatric oncologists had a limited understanding of PPC and reported limited practical implementation of PPC,which leads to underutilization of PPC resources.

关键词： Pediatrics Palliative care China Oncologist

Discovery of orthorhombic perovskite oxides with low thermal conductivity by first-principles calculations

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Journal of Advanced Ceramics 2022年第10期11卷 1596-1603页

作者： yuchen LIU Kaili CHU Yu zhou Yiran LI Wenxian LI Bin LIU Institute for Advanced Ceramics School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150080China School of Materials Science and Engineering Shanghai UniversityShanghai 200444China School of Materials Science and Engineering University of New South WalesSydney 2052Australia

Orthorhombic perovskite oxides are studied by high-throughput first-principles calculations to explore new thermal barrier coating(TBC)materials with low thermal conductivities.The mechanical and thermal properties are predicted for 160 orthorhombic perovskite oxides.The average atomic volume is identified as a possible predictor of the thermal conductivity for the perovskite oxides,as it has a good correlation with the thermal conductivity.Five compounds,i.e.,LaTmO_(3),LaErO_(3),LaHoO_(3),SrCeO_(3),and SrPrO_(3),having thermal conductivities under 1 W·m^(-1)·K^(-1) and good damage tolerance,are proposed as novel TBC materials.The obtained data are expected to inspire the design of perovskite oxide-based TBC materials and also support their future functionality investigations.

关键词： first-principles calculations perovskite oxide thermal conductivity mechanical property