面向DAG任务的分布式智能计算卸载和服务缓存联合优化

建立了一种有向无环图(DAG,directed acyclic graph)任务卸载和资源优化问题,旨在应用最大可容忍时延等约束实现系统能耗最小化。考虑到网络中计算请求高度动态、完整的系统状态信息难以获取等因素,最后使用多智能体深度确定性策略梯度(MADDPG,multi-agent deep deterministic policy gradient)算法来探寻最优的策略。相比于现有的任务卸载算法,MADDPG算法能够降低14.2%至40.8%的系统平均能耗,并且本地缓存命中率提高3.7%至4.1%。

儿童新型冠状病毒感染并发纵隔气肿八例影像学及临床特点研究

背景儿童新型冠状病毒感染(COVID-19)影像学与成人有一定差异,主要表现为胸膜下磨玻璃影、斑片状高密度影、实变影等,合并纵隔气肿者并不多见。大量气肿形成可严重影响呼吸及循环功能,导致明显喘憋、低氧血症,需积极处理。目的分析并总结儿童COVID-19并发纵隔气肿的影像学及临床特征。方法回顾分析2022-12-01—2023-01-30在长江大学附属荆州医院儿科住院的8例COVID-19并发纵隔气肿的患儿年龄、性别、影像学、临床特点及诊疗情况。结果8例患儿年龄3岁7个月~12岁,男女比3∶5,高分辨率CT(HRCT)均显示双肺感染合并纵隔气肿。气肿多同时累及颈部及胸壁。肺部表现多种多样:胸膜下磨玻璃影、实变、树芽征、支气管血管束增粗、支气管壁增厚及网格征等,未见大片实变及“白肺”。1例患儿合并少量胸腔积液。临床表现除有发热、咳嗽外,均有明显气促,肺部听诊干湿啰音可不显著。4例合并肺炎支原体感染、1例合并卡他布兰汉菌感染。合并肺炎支原体感染者应用阿奇霉素,合并卡他布兰汉菌感染者给予头孢噻肟治疗。8例患儿均给予氧疗。1例患儿白细胞总数及超敏C反应蛋白明显升高,明显气急,低氧血症,常规治疗无好转,给予有创呼吸机治疗3d后好转撤机。5例应用静脉丙种球蛋白(IVIG),3例使用糖皮质激素。1周后复查胸部CT,纵隔气肿均完全吸收,肺部病灶明显好转。结论COVID-19并发纵隔气肿者多为学龄前期或学龄期儿童,婴幼儿少见。可同时合并颈部及胸壁积气。肺部病变可累及间质或实质、双肺均受累,表现形式多样。起病多有明显气急,积极氧疗。白细胞计数明显升高,同时超敏C反应蛋白明显升高者,要密切关注呼吸情况,积极使用IVIG,适时适量应用糖皮质激素,必要时采用呼吸机人工辅助通气。

Generalization of Results of Computations and Natural Experiments at Steel Parts Quenching

Complicated changes occur inside the steel parts during quenching process. A three dimensional nonlinear mathematical model for quenching process has been established and the numerical simulation on temperature field, microstructure and stress field has been realized. The alternative technique for the formation of high-strength materials has been developed on the basis of intensification of heat transfer at phase transformations. The technology for the achievement of maximum compressive residual stresses on the hard surface is introduced. It has been shown that there is an optimal depth of hard layer providing the maximum compression stresses on the surface. It has also been established that in the surface hard layer additional strengthening (superstrengthening) of the material is observed. The generalized formula for the determination of the time of reaching maximum compressive stresses on the surface has been proposed.

基于空中计算CoMAC架构的不同计算场景叠加符号判决算法

本文研究不同场景下基于空中计算的多址信道计算(CoMAC)架构的覆盖符号决策算法。首先,从理论上分析了XOR、ADD、MOD三种场景中加性高斯白噪声(AWGN)多址接入信道下叠加符号的概率密度分布,提出了一种基于先验概率的最优门限判决策略。其次,推导了系统最优门限及对应误码率的理论表达式。最后,通过仿真验证了不同信噪比、传感器节点个数及先验概率对于该门限判决方案的鲁棒性和可靠性的影响。与通信计算相分离的传统方案相比,空中计算判决方案具有更好的检测性能,为多址接入信道下的信号识别提供了新的参考方案。

Primary parenchymal squamous cell carcinoma of the kidney:A case report

BACKGROUND Primary squamous cell carcinoma(SCC)of the renal parenchyma is extremely rare,with only nine cases reported.CASE SUMMARY This study reports a 51-year-old man with primary SCC of the renal parenchyma.The patient was admitted with recurrent dull pain and discomfort in the right lumbar region,which had worsened over 2 weeks,accompanied by painful gross hematuria.SCC antigen(SCCA)levels were elevated,and imaging revealed a renal mass with associated calculi.The patient underwent laparoscopic unilateral nephrectomy and lymph node dissection.Postoperative pathology confirmed highly differentiated SCC with necrosis in the right renal parenchyma,with negative renal pelvis and ureter.The pathological stage was Pt3aN1M0.Four months after surgery,the tumor recurred with involvement of the liver,right psoas major muscle,and inferior vena cava.The patient refused chemotherapy and succumbed to the disease 6 months postoperatively due to disease progression.CONCLUSION We report a case of primary SCC of the renal parenchyma,a rare renal malignancy.The clinical symptoms,laboratory tests,and imaging findings are nonspecific,making accurate and timely diagnosis challenging.According to the literature,for patients with renal calculi accompanied by a renal mass,elevated serum SCCA levels,and magnetic resonance imaging showing cystic or cystic-solid masses within the kidney with pseudocapsules and heterogeneous mild enhancement,the possibility of this disease should be considered.

Radiomics and molecular analysis:Bridging the gap for predicting hepatocellular carcinoma prognosis

This editorial examines a recent study that used radiomics based on computed tomography(CT)to predict the expression of the fibroblast-related gene enhancer of zeste homolog 2(EZH2)and its correlation with the survival of patients with hepatocellular carcinoma(HCC).By integrating radiomics with molecular analysis,the study presented a strategy for accurately predicting the expression of EZH2 from CT scans.The findings demonstrated a strong link between the radiomics model,EZH2 expression,and patient prognosis.This noninvasive approach provides valuable insights into the therapeutic management of HCC.

Pulp health and calcific healing of a complicated crown–root fracture with additional root fracture in a maxillary incisor: A case report

BACKGROUND Complicated crown–root fracture (CRF) involves severe injury to the crown, root,and pulp, and may be accompanied by multiple root fractures. The loss of a toothhas lifelong consequences for children and teenagers, but the maintenance of pulphealth and the calcific healing of multiple root fractures are rarely reported in theliterature.CASE SUMMARY This case reports healing of a permanent tooth with complicated crown–root andadditional root fractures, in which pulp health was maintained. A 10-year-old girlfell and fractured the root of her maxillary left central incisor at the cervical level.After the coronal fragment was repositioned, the tooth was splinted until thetooth was no longer mobile, 2 years later. Eight years after treatment, the toothhas remained asymptomatic with vital pulp and localized gingival overgrowth.Cone-beam computed tomography revealed not only calcified healing of the CRFbut also spontaneous healing in an additional undiagnosed root fracture. Thefracture line on the enamel could not be healed by hard tissue and formed agroove in the cervical crown. It was speculated that the groove was related to thelocalized gingival overgrowth.CONCLUSION This case provides a clinical perspective of the treatment of a tooth with acomplicated CRF and an additional root fracture.

Realistic Efficiency Evaluations for Parallel Computations under Workstation Cluster

In recent years, high performance scientific computing under workstation cluster connected by local area network is becoming a hot point. Owing to both the longer latency and the higher overhead for protocol processing compared with the powerful single workstation capacity, it is becoming severe important to keep balance not only for numerical load but also for communication load, and to overlap communications with computations while parallel computing. Hence,our efficiency evaluation rules must discover these capacities of a given parallel algorithm in order to optimize the existed algorithm to attain its highest parallel efficiency. The traditional efficiency evaluation rules can not succeed in this work any more. Fortunately, thanks to Culler's detail discuss in LogP model about interconnection networks for MPP systems, we present a system of efficiency evaluation rules for parallel computations under workstation cluster with PVM3.0 parallel software framework in this paper. These rules can satisfy above acquirements successfully. At last, two typical synchronous,and asynchronous applications are designed to verify the validity of these rules under 4 SGIs workstations cluster connected by Ethernet.

不同弹性模量计算机辅助设计和计算机辅助制造桩核材料的应力分析

背景:桩核修复是牙体缺损修复的一种常规选择,然而不同桩核材料的修复效果存在差异。目的:利用有限元方法评估不同弹性模量桩核修复模型中桩核与牙根黏结剂部位的应力分布情况。方法:在三维建模软件中构建一个三维根管治疗过的上颌中切牙模型,进行全瓷冠修复,修复中的桩核材料分别使用纳米陶瓷树脂(弹性模量12.8 GPa)、复合树脂(弹性模量16 GPa)、混合陶瓷(弹性模量34.7 GPa)、玻璃陶瓷(弹性模量95 GPa)、钛合金(弹性模量112 GPa)和氧化锆(弹性模量209.3 GPa),将模型约束在皮质骨中,在中切牙牙冠舌侧1/3处加载与牙体长轴呈45°的100 N集中力,通过最大主应力分析修复模型中桩核、牙本质及桩与牙根黏结剂的应力分布。结果与结论:(1)当使用弹性模量较高的桩核材料时,修复模型中的桩核应力较集中;当使用弹性模量接近牙本质的桩核材料(纳米陶瓷树脂和复合树脂)时,桩核的应力分布较均匀;无论桩核材料如何,各修复模型中牙本质上的应力分布相似;使用弹性模量更高的桩核时,修复模型中桩与牙根黏结剂处显示出更多的应力集中。(2)纳米陶瓷树脂模型中桩核、牙根及桩与牙根黏结剂处的最大应力值分别为31.00,33.21,0.51 MPa,复合树脂模型中桩核、牙根及桩与牙根黏结剂处的最大应力值分别为36.84,33.14,0.59 MPa,混合陶瓷模型中桩核、牙根及桩与牙根黏结剂处的最大应力值分别为64.05,32.83,1.00 MPa,玻璃陶瓷模型中桩核、牙根及桩与牙根黏结剂处的最大应力值分别为112.30,32.69,1.73 MPa,钛合金模型中桩核、牙根及桩与牙根黏结剂处的最大应力值分别为120.00,32.17,1.86 MPa,氧化锆模型中桩核、牙根及桩与牙根黏结剂处的最大应力值分别为148.80,31.85,2.28 MPa。(3)桩核材料的弹性模量越高,进行桩核修复时桩核处的最大应力值越大,桩核材料弹性模量对修复模型中桩与牙根黏结剂处与牙本质的最大应力值无明显影响。

导航辅助全膝关节置换应用功能学对线恢复患者固有生理力线和关节线倾角

背景:机械轴对线是全膝关节置换术中的“金标准”对线技术,但是无论假体材料和导航机器人辅助技术如何发展,应用机械轴对线的全膝关节置换后仍存在20%左右的患者不满意率。目的:探讨导航辅助全膝关节置换过程中应用功能学对线的早期疗效。方法:回顾性分析2019年10月至2023年6月连续44例(50膝)行计算机导航辅助全膝关节置换术中应用功能学对线的患者资料,男12例(14膝),女32例(36膝);选择同期同一手术团队行导航辅助全膝关节置换术中应用机械轴对线的46例(50膝)连续病例作为对照,男5例(5膝),女41例(45膝)。观察两组顾患者胫骨侧截骨角度、胫骨平台截骨量、股骨侧截骨角度、股骨远端、后方及前方截骨量、关节线移动情况;对比术前、术后屈曲和伸直间隙内外侧松弛度、髋-膝-踝角、股骨远端机械轴外侧角、胫骨近端机械轴内侧角、关节汇聚角、矢状面股骨组件角、胫骨后倾角、算术髋-膝-踝角、关节线倾角、膝关节冠状面力线分型、西安大略和麦克马斯特大学骨关节炎指数、美国特种外科医院评分及膝关节遗忘评分。结果与结论:①功能学对线组术中胫骨平台截骨角度大于机械轴对线组,间隙不平衡比例(2%)小于机械轴对线组(18%),差异均有显著性意义(P<0.05);②术后功能学对线组髋-膝-踝角、胫骨近端机械轴内侧角、算术髋-膝-踝角、关节线倾角小于机械轴对线组,差异均有显著性意义(P<0.05);③术前最常见的膝关节冠状面力线分型是Ⅰ型(功能学对线组80%,机械轴对线组42%);④术后功能学对线组关节线倾角<177°比例为44%,大于机械轴对线组的14%;⑤功能学对线组术后1,6个月及末次随访美国特种外科医院评分高于机械轴对线组,差异均有显著性意义(P<0.05);功能学对线组术后1个月西安大略和麦克马斯特大学骨关节炎指数低于机械轴对线组,差异有显著性意义(t=-2.85,P=0.005);两组术后膝关节活动度及膝关节遗忘评分相比差异均无显著性意义(P>0.05);⑥提示导航辅助全膝关节置换应用功能学对线能够优化早期临床疗效;与机械轴对线相比,功能学对线在恢复患者固有生理力线和关节线倾角、避免软组织松解方面更具优势。

脑机接口技术在脑卒中患者下肢功能康复中的应用前景

背景:近年来,脑机接口技术通过对动作意图的识别实现对外部设备的操控,改变了人类与计算机的交互方式,可用于脑卒中后下肢功能的治疗,为脑卒中患者康复带来了新的希望。目的:分析和总结近些年脑机接口技术在脑卒中患者下肢运动功能康复中的应用,探讨脑机接口技术在脑卒中患者下肢功能康复中的临床应用价值。方法:以“脑卒中,脑机接口,下肢”为中文检索词,在中国知网进行相关文献检索;以“stroke,brain-computer interfaces,lower extremity”为英文检索词,在PubMed数据库进行相关文献检索,检索时间范围为2014年1月至2024年6月。结果与结论:脑机接口对脑卒中患者下肢运动功能恢复具有良好的应用前景,在康复医学应用领域正在不断扩大,但其机制尚未完全阐释清楚;此外,在采集患者脑电信号方面存在一定的局限,导致脑机接口系统精确识别肢体运动的能力较差,并且目前该技术的解码方法对识别步态周期存在局限性,不能精确定位到下肢各关节与肌肉的随意运动,阻碍了脑机接口技术的应用。未来的研究应该集中在阐明脑机接口技术对脑卒中患者下肢运动功能恢复的神经机制,增强大脑运动信号提取技术和设备,为个体患者制定多模态反馈实现更有效的运动康复,以期推动脑机接口技术在下肢运动功能康复领域的进一步发展,改善患者的康复效果,提高生活质量。

Aircraft noise and its nearfield propagation computations

Noise generated by civil transport aircraft during take-off and approach-to-land phases of operation is an environmental problem. The aircraft noise problem is firstly reviewed in this article. The review is followed by a description and assessment of a number of sound propagation methods suitable for applications with a background mean flow field pertinent to aircraft noise. Of the three main areas of the noise problem, i.e. generation, propagation, and ra- diation, propagation provides a vital link between near-field noise generation and far-field radiation. Its accurate assessment ensures the overall validity of a prediction model. Of the various classes of propagation equations, linearised Euler equations are often casted in either time domain or frequency domain. The equations are often solved numerically by computational aeroacoustics techniques, bur are subject to the onset of Kelvin-Helmholtz （K-H） instability modes which may ruin the solutions. Other forms of linearised equations, e.g. acoustic perturbation equations have been proposed, with differing degrees of success.

数字化精准全膝关节置换与传统置换方法的短期效果对比

背景:传统全膝关节置换手术在术前的准备有限,作者提出基于计算机仿真和3D打印技术的数字化精准全膝置换方法,旨在通过充分的术前设计来提升置换效果。目的:利用计算机仿真和个性化手术导板建立数字化精准全膝关节置换方法,比较新方法和传统方法的临床效果。方法:回顾性分析97例全膝关节置换患者的临床资料,根据手术方法将患者分为2组,对照组(n=48)采取传统方式进行全膝关节置换手术,使用传统胶片模板;观察组(n=49)采用数字化精准全膝置换方法进行手术,使用计算机辅助技术选定假体尺寸型号。比较两组患者的手术时间、术中出血量、术前及术后美国特种外科医院膝关节评分以及股骨力线和膝关节面线夹角和胫骨角、髋膝踝角与标准角度的差值。结果与结论:(1)两组患者术前性别、年龄、体质量指数、美国特种外科医院膝关节评分,以及胫骨角、股骨力线和膝关节面线夹角、髋膝踝角与标准角度的差值相比差异均无显著性意义(P> 0.05);(2)与对照组比较,观察组手术时间缩短、出血量减少;两组术后3个月膝关节美国特种外科医院膝关节评分对比术前均显著升高(P> 0.05),且术后3个月观察组评分高于对照组(P> 0.05);(3)两组之间胫骨角、股骨力线和膝关节面线夹角、髋膝踝角与标准角度的差值相比差异均有显著性意义,观察组优于对照组(P <0.05);(4)观察组股骨假体预测准确率为94%,对照组为58%;胫骨假体预测准确率为96%,对照组为62%;(5)提示数字化精准全膝关节置换相较传统全膝关节置换的手术时间更短、出血量更少、术后膝关节功能评分和力线恢复更好,具有良好的短期临床效果。

基于测量的盲量子计算研究进展

量子计算机具有广阔的前景和发展潜力,但其物理实现目前面临巨大挑战。基于测量的盲量子计算,由于其允许量子能力有限甚至没有量子能力的普通用户,可通过借助远程量子服务器,使用基于测量的量子计算模型完成计算任务,并保证其数据、算法和结果的私密性。因此,这种委托量子计算的方式将成为未来普通用户共享量子计算资源的一种重要应用模式。基于此,阐述了基于测量的量子计算模型包括的两种常用资源态—簇态和图态,以及测量模式的定义和形式化描述;分析了基于测量的盲量子计算的基本原理,包括通用资源态—Brickwork态的构造、盲量子计算测量模式和通用盲量子计算协议;梳理了解决基于测量的盲量子计算根本问题的不同技术路线和实验成果;探讨了其未来的发展方向。

Three-Di mensional Computations of Multiple TandemJets in Crossflow

The mixing and merging characteristics of multiple tandem jets in crossflow are investigated by use of the Computational Fluid Dynamics （CFD） code FI,UENT. The realizable k - ε model is employed for turbulent elosure of the Reynolds-averaged Navier-Stokes equations. Numerical experiments are performed for 1-, 2- and 4-jet groups, tbr jet-tocrossflow velocity ratios of R = 4.2 ～ 16.3. The computed velocity and scalar concentration field are in good agreement with experiments using Particle Image Velocimetry （PIV） and Laser Induced Fluorescence （LIF）, as well as previous work. The results show that the leading jet behavior is similar to a single free jet in crossflow, while all the downstream rear jets have less bent-over jet trajectories - suggesting a reduced ambient velocity for the rear jets. The concentration decay of the leading jet is greater than that of the rear jets. When normalized by appropriate crossflow momentum length scales, all jet trajectories follow a universal relation regardless of the sequential order of jet position and the nund）er of jets. Supported by the velocity and trajectory measurements, the averaged maximum effective crossflow velocity ratio is computed to be in the range of 0.39 to 0.47.

Novel Approach to Data Encryption Based on Matrix Computations

In this paper,we provide a new approach to data encryption using generalized inverses.Encryption is based on the implementation of weighted Moore–Penrose inverse A y MNenxmT over the nx8 constant matrix.The square Hermitian positive definite matrix N8x8 p is the key.The proposed solution represents a very strong key since the number of different variants of positive definite matrices of order 8 is huge.We have provided NIST(National Institute of Standards and Technology)quality assurance tests for a random generated Hermitian matrix(a total of 10 different tests and additional analysis with approximate entropy and random digression).In the additional testing of the quality of the random matrix generated,we can conclude that the results of our analysis satisfy the defined strict requirements.This proposed MP encryption method can be applied effectively in the encryption and decryption of images in multi-party communications.In the experimental part of this paper,we give a comparison of encryption methods between machine learning methods.Machine learning algorithms could be compared by achieved results of classification concentrating on classes.In a comparative analysis,we give results of classifying of advanced encryption standard(AES)algorithm and proposed encryption method based on Moore–Penrose inverse.

口腔种植修复中钛基底氧化锆基台的制作和力学性能

背景:随着计算机辅助设计和计算机辅助制造技术的发展,钛基底氧化锆基台因具备良好的应用优势被广泛运用于临床,但仍存在一些问题,尚缺乏共识性的设计标准。目的:综述钛基底氧化锆基台的制作方法及基台连接、穿龈设计、基台角度和粘接对钛基底氧化锆基台各类力学性能的影响。方法:检索Pub Med数据库和中国知网2010-2023年发表的相关文献,检索词为“zirconia abutment,titanium base;氧化锆基台,钛基底”,部分经典文献延长检索时间限制,通过纳入和排除标准获取相关文献,对57篇符合标准的文献进行综述。结果与结论:建议临床医生尽量选择具有抗旋结构的基台连接或是具有莫氏锥度的非抗旋连接,当运用钛基底氧化锆基台时,种植体应放置在正确的轴向角度(植体轴向向唇侧倾斜角度不超过15°或略向腭侧倾斜);当植体轴向向唇侧倾斜角度≥30°时,应当适当降低咬合力,以降低种植体、基台及修复体机械并发症和生物并发症的风险;应尽可能选择穿龈高度较高的钛基底,并且其穿龈角度不应超过40°。Multilink Hybrid Abutment可以作为氧化锆基台与钛基底口外粘结的首选粘接剂。

Computationally efficient direction finding using polynomial rooting with reduced-order and real-valued computations

The root multiple signal classification（root-MUSIC） algorithm is one of the most important techniques for direction of arrival（DOA） estimation. Using a uniform linear array（ULA） composed of M sensors, this method usually estimates L signal DOAs by finding roots that lie closest to the unit circle of a（2M-1）-order polynomial, where L 〈 M. A novel efficient root-MUSIC-based method for direction estimation is presented, in which the order of polynomial is efficiently reduced to 2L. Compared with the unitary root-MUSIC（U-root-MUSIC） approach which involves real-valued computations only in the subspace decomposition stage, both tasks of subspace decomposition and polynomial rooting are implemented with real-valued computations in the new technique,which hence shows a significant efficiency advantage over most state-of-the-art techniques. Numerical simulations are conducted to verify the correctness and efficiency of the new estimator.

Efficient and Robust Design for Absorbing Boundary Conditions in Atomistic Computations

We propose an efficient and robust way to design absorbing boundary conditions in atomistic computations. An optimal discrete boundary condition is obtained by minimizing a functional of a reflection coefficient integral over a range of wave numbers. The minimization is performed with respect to a set of wave numbers, at which transparent absorption is reached. Compared with the optimization with respect to the boundary condition coefficients suggested by E and Huang [Phys. Rev. Lett. 87 （2001） 133501], we reduce considerably the number of independent variables and the computing cost. We further demonstrate with numerical examples that both the optimization and the wave absorption are more robust in the proposed design.

On the Tempo-Spatial Evolution of the Lower Ionospheric Perturbation for the 2016 Kumamoto Earthquakes from Comparisons of VLF Propagation Data Observed at Multiple Stations with Wave-Hop Theoretical Computations

There have been published many papers on VLF (very low frequency) characteristics to study seismo-ionospheric perturbations. Usually VLF records (amplitude and/or phase) are used to investigate mainly the temporal evolution of VLF propagation anomalies with special attention to one particular propagation path. The most important advantage of this paper is the simultaneous use of several propagation paths. A succession of earthquakes (EQs) happened in the Kumamoto area in Kyusyu Island;two strong foreshocks with magnitude of 6.5 and 6.4 on 14 April (UT) and the main shock with magnitude 7.3 on 15 April (UT). Because the EQ epicenters are not far from the VLF transmitter (with the call sign of JJI in Miyazaki prefecture), we can utilize simultaneously 8 observing stations of our network all over Japan. Together with the use of theoretical computations based on wave-hop theory, we try to trace both the temporal and spatial evolutions of the ionospheric perturbation associated with this succession of EQs. It is found that the ionospheric perturbation begins to appear about two weeks before the EQs, and this perturbation becomes most developed 5 - 3 days before the main shock. When the perturbation is most disturbed, the maximum change in vertical direction is depletion in the VLF effective ionospheric height of the order of 10 km, and its horizontal scale (or its radius) is about 1000 km. These spatio-temporal changes of the seismo-ionospheric perturbation will be investigated in details in the discus-sion, a comparison has made with the VLF characteristics of the 1995 Kobe with the same magnitude and of the same fault-type, and a brief discussion on the generation mechanism of seismo-ionospheric perturbation is finally made.