公有链无集中控制节点、去中心化和允许任意节点加入的特点使其拥有高效、低成本和高数据安全性的优势,但由于其允许任意节点接入,因此将增加公有链网络的脆弱性。基于Client Puzzle,提出一种节点接入控制模型CPACM(Client Puzzle based...公有链无集中控制节点、去中心化和允许任意节点加入的特点使其拥有高效、低成本和高数据安全性的优势,但由于其允许任意节点接入,因此将增加公有链网络的脆弱性。基于Client Puzzle,提出一种节点接入控制模型CPACM(Client Puzzle based Access Control Model),使新节点接入公有链前利用算力进行工作量证明,完成工作量证明后才可接入公有链。该模型在维持公有链去中心化的同时,增加了接入控制。实验证明,该模型在不影响诚实节点加入的情况下,能以较高成功率限制低诚意节点和低算力节点的加入,并且能防止节点间的伙同,防范了恶意行为,提高了公有链网络的安全性。展开更多
Benign prostatic hyperplasia(BPH)is a common condition affecting over 50% of men as they reach the 5th decade of their life[1].While over half of these patients have symptoms,it is not clear why some of these men do w...Benign prostatic hyperplasia(BPH)is a common condition affecting over 50% of men as they reach the 5th decade of their life[1].While over half of these patients have symptoms,it is not clear why some of these men do while others do not.The article Solving the benign prostatic hyperplasia puzzle by Keong Tatt Foo[2],delves into the different conundrums urologists face when trying to treat their patients.展开更多
From 1985, an increasing gap has emerged between the official statistical measures of meat production and meat consumption in China, which has raised concerns from many researchers using such data. In this paper we re...From 1985, an increasing gap has emerged between the official statistical measures of meat production and meat consumption in China, which has raised concerns from many researchers using such data. In this paper we report the results of 428 observations（survey of 107 urban and rural households×4 quarters） from 7 provinces conducted in 2010, and compare them with the official statistical data from the National Bureau of Statistics of China（NBSC）. We conclude that the main reason for the discrepancy is due to the underreporting of consumption, which is due mainly to the omission of consumption away from home.展开更多
Current image steganography methods are working by assigning an image as a cover file then embed the payload within it by modifying its pixels,creating the stego image.However,the left traces that are caused by these ...Current image steganography methods are working by assigning an image as a cover file then embed the payload within it by modifying its pixels,creating the stego image.However,the left traces that are caused by these modifications will make steganalysis algorithms easily detect the hidden payload.A coverless data hiding concept is proposed to solve this issue.Coverless does not mean that cover is not required,or the payload can be transmitted without a cover.Instead,the payload is embedded by cover generation or a secret message mapping between the cover file and the payload.In this paper,a new coverless image steganography method has been proposed based on the jigsaw puzzle image generation driven by a secret message.Firstly,the image is divided into equal rows then further divided into equal columns,creating blocks(i.e.,sub-images).Then,according to secret message bits and a proposed mapping function,each block will have tabs/blanks to get the shape of a puzzle piece creating a fully shaped jigsaw puzzle stego-image.After that,the generated jigsaw puzzle image is sent to the receiver.Experimental results and analysis show a good performance in the hiding capacity,security,and robustness compared with existing coverless image steganography methods.展开更多
BACKGROUND Microcystic adnexal carcinoma(MAC)is a rare malignant tumor of the skin that is commonly found on the face.It grows slowly and has a low mortality rate.However,for various reasons,including strong histologi...BACKGROUND Microcystic adnexal carcinoma(MAC)is a rare malignant tumor of the skin that is commonly found on the face.It grows slowly and has a low mortality rate.However,for various reasons,including strong histological invasiveness,clinical inexperience and inadequate procedure design,immediate or permanent facial deformity may occur after surgical operations.CASE SUMMARY This article describes a middle-aged female artist who was diagnosed with MAC on the left upper lip.She declined the recommended treatment plan,which included two-stage reconstruction,skin grafting,or surgery that could have resulted in obvious facial dysfunction or esthetic deformity.We accurately designed a personalized procedure involving a“jigsaw puzzle advancement flap”for the patient based on the lesion location and the estimated area of skin loss.The procedure was successful;both pathological R0 resection and immediate and long-term esthetic reconstruction effects were achieved.CONCLUSION This study suggests that when treating facial MAC or other skin malignancies,a surgical team should have sufficient plastic surgery-related knowledge and skills.An optimal surgical plan for an individual is needed to achieve good facial esthetics and functional recovery and shorten the treatment course.展开更多
There are diverse opinions about how to solve the Needham Puzzle. Such opinions or schools of thought can be roughly classified into three theories of a) geographical conditions, b) empirical trial and error, and c) p...There are diverse opinions about how to solve the Needham Puzzle. Such opinions or schools of thought can be roughly classified into three theories of a) geographical conditions, b) empirical trial and error, and c) private property rights. Although each school of thought makes sense, they all fail to fully uncover the main reason why, in modern history, China lagged behind western countries in the development of science and technology. In our opinion, the correct solution is to draw on historical experiences, integrate all schools of thought, proceed with an emphasis on the definition and protection of property rights, boost government investment in basic scientific research, strengthen government service functionality, actively develop NGOs, and open more widely to the outside world, with a view of pushing forward China's scientific and technological innovation and accelerating the pace of China's modernization.展开更多
Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect inf...Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect influence exporting firms' markup. Our findings suggest that the interaction between selection effect and competition effect ultimately causes actual firm markup to be higher than the baseline markup by 7.11%. Exporting firms' actual markup is higher than the baseline markup by different degrees. In terms of the decomposition of selection effect, TFP explains for 28.05% of selection effect, and nonproductivity factors explain for the rest 71.95%. By controlling for the type of firms' export,the export-productivity paradox only exists for processing trade firms, which shows that with increasing trade facilitation, the policy incentives to encourage firms to export are major contributors to the low export markups.展开更多
文摘公有链无集中控制节点、去中心化和允许任意节点加入的特点使其拥有高效、低成本和高数据安全性的优势,但由于其允许任意节点接入,因此将增加公有链网络的脆弱性。基于Client Puzzle,提出一种节点接入控制模型CPACM(Client Puzzle based Access Control Model),使新节点接入公有链前利用算力进行工作量证明,完成工作量证明后才可接入公有链。该模型在维持公有链去中心化的同时,增加了接入控制。实验证明,该模型在不影响诚实节点加入的情况下,能以较高成功率限制低诚意节点和低算力节点的加入,并且能防止节点间的伙同,防范了恶意行为,提高了公有链网络的安全性。
文摘Benign prostatic hyperplasia(BPH)is a common condition affecting over 50% of men as they reach the 5th decade of their life[1].While over half of these patients have symptoms,it is not clear why some of these men do while others do not.The article Solving the benign prostatic hyperplasia puzzle by Keong Tatt Foo[2],delves into the different conundrums urologists face when trying to treat their patients.
基金supported by the Earmarked Fund for Modern Agro-Industry Technology Research System,China(CARS-42-G24)the Agricultural Science and Technology Innovation Program,China(ASTIP-IAED-2015-01)+1 种基金the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges Under Beijing Municipality,China(IDHT20140510)the Project of Strategy of Ensuring China’s Animal Products Eatable Safety(13BGL098)
文摘From 1985, an increasing gap has emerged between the official statistical measures of meat production and meat consumption in China, which has raised concerns from many researchers using such data. In this paper we report the results of 428 observations（survey of 107 urban and rural households×4 quarters） from 7 provinces conducted in 2010, and compare them with the official statistical data from the National Bureau of Statistics of China（NBSC）. We conclude that the main reason for the discrepancy is due to the underreporting of consumption, which is due mainly to the omission of consumption away from home.
基金funded by“Taif University Researchers Supporting Project No.(TURSP-2020/160),Taif University,Taif,Saudi Arabia.”。
文摘Current image steganography methods are working by assigning an image as a cover file then embed the payload within it by modifying its pixels,creating the stego image.However,the left traces that are caused by these modifications will make steganalysis algorithms easily detect the hidden payload.A coverless data hiding concept is proposed to solve this issue.Coverless does not mean that cover is not required,or the payload can be transmitted without a cover.Instead,the payload is embedded by cover generation or a secret message mapping between the cover file and the payload.In this paper,a new coverless image steganography method has been proposed based on the jigsaw puzzle image generation driven by a secret message.Firstly,the image is divided into equal rows then further divided into equal columns,creating blocks(i.e.,sub-images).Then,according to secret message bits and a proposed mapping function,each block will have tabs/blanks to get the shape of a puzzle piece creating a fully shaped jigsaw puzzle stego-image.After that,the generated jigsaw puzzle image is sent to the receiver.Experimental results and analysis show a good performance in the hiding capacity,security,and robustness compared with existing coverless image steganography methods.
文摘BACKGROUND Microcystic adnexal carcinoma(MAC)is a rare malignant tumor of the skin that is commonly found on the face.It grows slowly and has a low mortality rate.However,for various reasons,including strong histological invasiveness,clinical inexperience and inadequate procedure design,immediate or permanent facial deformity may occur after surgical operations.CASE SUMMARY This article describes a middle-aged female artist who was diagnosed with MAC on the left upper lip.She declined the recommended treatment plan,which included two-stage reconstruction,skin grafting,or surgery that could have resulted in obvious facial dysfunction or esthetic deformity.We accurately designed a personalized procedure involving a“jigsaw puzzle advancement flap”for the patient based on the lesion location and the estimated area of skin loss.The procedure was successful;both pathological R0 resection and immediate and long-term esthetic reconstruction effects were achieved.CONCLUSION This study suggests that when treating facial MAC or other skin malignancies,a surgical team should have sufficient plastic surgery-related knowledge and skills.An optimal surgical plan for an individual is needed to achieve good facial esthetics and functional recovery and shorten the treatment course.
文摘There are diverse opinions about how to solve the Needham Puzzle. Such opinions or schools of thought can be roughly classified into three theories of a) geographical conditions, b) empirical trial and error, and c) private property rights. Although each school of thought makes sense, they all fail to fully uncover the main reason why, in modern history, China lagged behind western countries in the development of science and technology. In our opinion, the correct solution is to draw on historical experiences, integrate all schools of thought, proceed with an emphasis on the definition and protection of property rights, boost government investment in basic scientific research, strengthen government service functionality, actively develop NGOs, and open more widely to the outside world, with a view of pushing forward China's scientific and technological innovation and accelerating the pace of China's modernization.
基金Sponsorship of the National Social Science Foundation (NSSF) Youth Project (16CJL014)the China Postdoctoral Science Special Foundation (2017T100001)
文摘Based on China's industrial enterprises-customs matched data, this paper utilizes two-tier stochastic frontier analysis method to estimate and verify the extent to which selection effect and competition effect influence exporting firms' markup. Our findings suggest that the interaction between selection effect and competition effect ultimately causes actual firm markup to be higher than the baseline markup by 7.11%. Exporting firms' actual markup is higher than the baseline markup by different degrees. In terms of the decomposition of selection effect, TFP explains for 28.05% of selection effect, and nonproductivity factors explain for the rest 71.95%. By controlling for the type of firms' export,the export-productivity paradox only exists for processing trade firms, which shows that with increasing trade facilitation, the policy incentives to encourage firms to export are major contributors to the low export markups.
