心脏病是美国最大的杀手,每年三分之一的死亡归咎于心脏病。因此。美国人对心脏病所投入的研究也是最可观的。本文的主题句很有文采,sunny outlook取代了optimistic outlooko sunny outlook的反面,就应该是gloomy outlooko我在上小学时...心脏病是美国最大的杀手,每年三分之一的死亡归咎于心脏病。因此。美国人对心脏病所投入的研究也是最可观的。本文的主题句很有文采,sunny outlook取代了optimistic outlooko sunny outlook的反面,就应该是gloomy outlooko我在上小学时,老师用一简单例子向我们说明乐观和悲观。她说,两个酒鬼喝剩半瓶酒。醒来一看,甲说,唉,只有半瓶酒了,乙说,哦,还有半瓶子酒! 只有≠还有。前者悲观,后者乐观!本文郑重提醒:Maybe adding a little fun to people's lives can work like medicine to help prevent heart disease.以前对“心脏病”的一个委婉说法是heart condition,本文又亮出一个“心脏病”的新说法:heart event,值得注意。】展开更多
心脏病是美国人的最大杀手,三分之一的美国人死于此疾。乐观对健康有益,本文对“乐观”的诠释却另辟蹊径:with a sunny(本义:阳光充足的) outlook(观点;简洁)on life/power of positive thinking。对生活抱“乐呵呵”的态度,同时又具有...心脏病是美国人的最大杀手,三分之一的美国人死于此疾。乐观对健康有益,本文对“乐观”的诠释却另辟蹊径:with a sunny(本义:阳光充足的) outlook(观点;简洁)on life/power of positive thinking。对生活抱“乐呵呵”的态度,同时又具有积极乐观思维者患心脏病或其他疾病的可能性大大降低！展开更多
Partial cooperation models are studied for many years to solve the bilevel programming problems where the follower’s optimal reaction is not unique. However, in these existed models, the follower’s cooperation level...Partial cooperation models are studied for many years to solve the bilevel programming problems where the follower’s optimal reaction is not unique. However, in these existed models, the follower’s cooperation level does not depend on the leader’s decision. A new model is proposed to solve this deficiency. It is proved the feasibility of the new model when the reaction set of the lower level is lower semicontinuous. And the numerical results show that the new model has optimal solutions when the reaction set of the lower level is discrete, lower semi-continuous and non-lower semi-continuous.展开更多
A key problem of electronic commerce （for short e-commerce） is fair exchange which guarantees that at the end of the transaction, either both parties involved in the trausaction receive each other＇s items or none d...A key problem of electronic commerce （for short e-commerce） is fair exchange which guarantees that at the end of the transaction, either both parties involved in the trausaction receive each other＇s items or none do. A non-interactive optimistic fair exchange e-commerce protocol model based on the publicly verifiable secret sharing is presented. The main idea of our exchange protocol is to interchange verifiable and recoverable keys of the symmetric encryption for participants＇ items. So it is especially suitable for exchange of large-size items. Furthermore, our protocol is efficient and simple as it does not need interactive proof system which has been adopted by a large quantity of previously proposed fair exchange protocols. Based on a modified （2,2） secret sharing scheme, a concrete non-interactive fair exchange e-commerce protocol is designed.展开更多
A DMVOCC-MVDA （distributed multiversion optimistic concurrency control with multiversion dynamic adjustment） protocol was presented to process mobile distributed real-time transaction in mobile broadcast environment...A DMVOCC-MVDA （distributed multiversion optimistic concurrency control with multiversion dynamic adjustment） protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load （think time is ls） the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols.展开更多
We have considered a method called Enhanced Rollback Migration Protocol, which potentially has the effects of compressing the period of compensations in a long-lived transaction, since before. In general, a compensati...We have considered a method called Enhanced Rollback Migration Protocol, which potentially has the effects of compressing the period of compensations in a long-lived transaction, since before. In general, a compensation transaction can recover an irregular status of a long-lived transaction into the original status without holding unnecessary resources by making its consistency tentatively loose. However, it has also been pointed out that there is a difficulty of maintaining the isolation between a pair of transactions when executed in parallel. In particular, this could be more prominent under modernized scalable cloud environments. Thus, there is a proposal for concurrency control for the service level. However, there is still another risk that more computer resources will be consumed than actually necessary and an unnecessary stagnation of the processing will be caused if concurrency control is naively applied without careful consideration. Therefore, we need to implement a functionality which can optimize the processing of a long-lived transaction by selecting a suitable method between concurrency control and compensation transactions. In this paper, we propose a method in which optimistic concurrency control is applied for long-lived transactions. Furthermore, a pair of verification phases is carried out. At the beginning from a safe point, an attempt of verification is done. Then if the difficulty of isolation on a long-lived transaction executed under a competitive situation is estimated, concurrency control for the service level is applied. Alternatively, a long-lived transaction without any concurrency control is executed. At the next reachable safe point, another attempt of verification is performed. Then if a failure of serialization is detected, a set of compensation transactions is invoked to recover the original long-lived transaction by returning to the first safe point. We evaluated this approach by using numerical simulations and confirmed the basic features. This approach can realize optimizing and enhancing the performance of a long-lived transaction. We regard this approach applicable even to the modernized scalable cloud environments.展开更多
As the representative of mature investors, security analysts＇ recommendations are guidance for most investors, However, a great deal of studies nearly draws the consistent conclusion, i.e. they are not as smart as we...As the representative of mature investors, security analysts＇ recommendations are guidance for most investors, However, a great deal of studies nearly draws the consistent conclusion, i.e. they are not as smart as we imagine, or the market doesn＇t trust their recommendations so much. The existence of optimistic bias in their recommendations has been supported by empirical data widely. Hence these make many papers to explore the reasons and try to give theoretical explanations. Based on prior researches, this paper mainly compares two theoretical models both based on mathematical methods.展开更多
Regarding the global oil and gas market in 2018,some people are optimistic, others are worried, and it is fair to describe the market as complex and volatile. In his speech at the annual meeting of the Beijing Energy ...Regarding the global oil and gas market in 2018,some people are optimistic, others are worried, and it is fair to describe the market as complex and volatile. In his speech at the annual meeting of the Beijing Energy Club in mid-December 2018, Mr. Zhang Guobao.展开更多
Cyber threats and risks are increasing exponentially with time. For preventing and defense against these threats and risks, precise risk perception for effective mitigation is the first step. Risk perception is necess...Cyber threats and risks are increasing exponentially with time. For preventing and defense against these threats and risks, precise risk perception for effective mitigation is the first step. Risk perception is necessary requirement to mitigate risk as it drives the security strategy at the organizational level and human attitude at individual level. Sometime, individuals understand there is a risk that a negative event or incident can occur, but they do not believe there will be a personal impact if the risk comes to realization but instead, they believe that the negative event will impact others. This belief supports the common belief that individuals tend to think of themselves as invulnerable, i.e., optimistically bias about the situation, thus affecting their attitude for taking preventive measures due to inappropriate risk perception or overconfidence. The main motivation of this meta-analysis is to assess that how the cyber optimistic bias or cyber optimism bias affects individual’s cyber security risk perception and how it changes their decisions. Applying a meta-analysis, this study found that optimistic bias has an overall negative impact on the cyber security due to the inappropriate risk perception and considering themselves invulnerable by biasing that the threat will not occur to them. Due to the cyber optimism bias, the individual will sometimes share passwords by considering it will not be maliciously used, lack in adopting of preventive measures, ignore security incidents, wrong perception of cyber threats and overconfidence on themselves in the context of cyber security.展开更多
THE long-term rise in exports has made an undeniable contribution to China＇s economic growth. As the world＇s biggest commodities trader, China＇s reliance on foreign trade was the highest among the world＇s economic...THE long-term rise in exports has made an undeniable contribution to China＇s economic growth. As the world＇s biggest commodities trader, China＇s reliance on foreign trade was the highest among the world＇s economic powers for many years.展开更多
Forum on China-Africa Cooperation prepares for the next 10 years of development AFTER a decade of robust development, the Forum on China-Africa Cooperation (FOCAC),a mechanism bridging the world’s largest developing ...Forum on China-Africa Cooperation prepares for the next 10 years of development AFTER a decade of robust development, the Forum on China-Africa Cooperation (FOCAC),a mechanism bridging the world’s largest developing country and the world’s largest developing continent,is preparing for development in the next decade with great optimism.展开更多
This year, the Fifth Ministerial Conference of the Forum on China-Africa Cooperation （FOCAC） will be held in China. Recently, Ambassador John Kayocle Shinkaiye, Chief of Staff, Bureau of the Chairperson of the Afric...This year, the Fifth Ministerial Conference of the Forum on China-Africa Cooperation （FOCAC） will be held in China. Recently, Ambassador John Kayocle Shinkaiye, Chief of Staff, Bureau of the Chairperson of the African Union Commission （AUC）, shared his thoughts with ChinAfrica reporter Liu Wei on the role that FOCAC has played in strengthening Sino-African relations, at the AU headquarters in Addis Ababa, Ethiopia. His thoughts are as follows展开更多
As an important fundamental industry of the national economy,the man-made fiber industrial chain is integrated into the era development and it assumes the responsibility of advancing.Each link of the industrial chain ...As an important fundamental industry of the national economy,the man-made fiber industrial chain is integrated into the era development and it assumes the responsibility of advancing.Each link of the industrial chain is connected with each other.After the development and accumulation of several decades,the new produced polyester,PTA and other plants keep展开更多
THE recent World Bank report of the continent＇s economy, ＂Africa＇s Pulse＂ laid out a very optimistic path for 2012. Coming offthe back of an average 4.9 percent growth in 2011, Sub-Saharan Africa is poised for goo...THE recent World Bank report of the continent＇s economy, ＂Africa＇s Pulse＂ laid out a very optimistic path for 2012. Coming offthe back of an average 4.9 percent growth in 2011, Sub-Saharan Africa is poised for good economic times ahead,展开更多
EACH new year promises much spirits are high, expectations large and friendships strengthened. By all accounts 2015 promises much for Sino-Affican cooperation. Admittedly, the threat of Ebola, as reported on extensive...EACH new year promises much spirits are high, expectations large and friendships strengthened. By all accounts 2015 promises much for Sino-Affican cooperation. Admittedly, the threat of Ebola, as reported on extensively in this magazine during 2014, casts a pall of negativity and tragic consequences across the continent, most notably West Africa. This killer pandemic, coupled with the perennial threat of instability and terrorism that haunts Africa, poses the biggest threat to development and the economy of the continent this year. It is little wonder then that China and Africa acknowledge the need to tightencooperation in these areas.展开更多
文摘心脏病是美国最大的杀手,每年三分之一的死亡归咎于心脏病。因此。美国人对心脏病所投入的研究也是最可观的。本文的主题句很有文采,sunny outlook取代了optimistic outlooko sunny outlook的反面,就应该是gloomy outlooko我在上小学时,老师用一简单例子向我们说明乐观和悲观。她说,两个酒鬼喝剩半瓶酒。醒来一看,甲说,唉,只有半瓶酒了,乙说,哦,还有半瓶子酒! 只有≠还有。前者悲观,后者乐观!本文郑重提醒:Maybe adding a little fun to people's lives can work like medicine to help prevent heart disease.以前对“心脏病”的一个委婉说法是heart condition,本文又亮出一个“心脏病”的新说法:heart event,值得注意。】
文摘心脏病是美国人的最大杀手,三分之一的美国人死于此疾。乐观对健康有益,本文对“乐观”的诠释却另辟蹊径:with a sunny(本义:阳光充足的) outlook(观点;简洁)on life/power of positive thinking。对生活抱“乐呵呵”的态度,同时又具有积极乐观思维者患心脏病或其他疾病的可能性大大降低！
基金supported by the National Natural Science Foundationof China (70771080)the National Science Foundation of Hubei Province(20091107)Hubei Province Key Laboratory of Systems Science in Metallurgical Process (B201003)
文摘Partial cooperation models are studied for many years to solve the bilevel programming problems where the follower’s optimal reaction is not unique. However, in these existed models, the follower’s cooperation level does not depend on the leader’s decision. A new model is proposed to solve this deficiency. It is proved the feasibility of the new model when the reaction set of the lower level is lower semicontinuous. And the numerical results show that the new model has optimal solutions when the reaction set of the lower level is discrete, lower semi-continuous and non-lower semi-continuous.
基金This project was partially supported by the National Natural Science Foundation of China (60273049, 90104005).
文摘A key problem of electronic commerce （for short e-commerce） is fair exchange which guarantees that at the end of the transaction, either both parties involved in the trausaction receive each other＇s items or none do. A non-interactive optimistic fair exchange e-commerce protocol model based on the publicly verifiable secret sharing is presented. The main idea of our exchange protocol is to interchange verifiable and recoverable keys of the symmetric encryption for participants＇ items. So it is especially suitable for exchange of large-size items. Furthermore, our protocol is efficient and simple as it does not need interactive proof system which has been adopted by a large quantity of previously proposed fair exchange protocols. Based on a modified （2,2） secret sharing scheme, a concrete non-interactive fair exchange e-commerce protocol is designed.
基金Project(20030533011)supported by the National Research Foundation for the Doctoral Program of Higher Education of China
文摘A DMVOCC-MVDA （distributed multiversion optimistic concurrency control with multiversion dynamic adjustment） protocol was presented to process mobile distributed real-time transaction in mobile broadcast environments. At the mobile hosts, all transactions perform local pre-validation. The local pre-validation process is carried out against the committed transactions at the server in the last broadcast cycle. Transactions that survive in local pre-validation must be submitted to the server for local final validation. The new protocol eliminates conflicts between mobile read-only and mobile update transactions, and resolves data conflicts flexibly by using multiversion dynamic adjustment of serialization order to avoid unnecessary restarts of transactions. Mobile read-only transactions can be committed with no-blocking, and respond time of mobile read-only transactions is greatly shortened. The tolerance of mobile transactions of disconnections from the broadcast channel is increased. In global validation mobile distributed transactions have to do check to ensure distributed serializability in all participants. The simulation results show that the new concurrency control protocol proposed offers better performance than other protocols in terms of miss rate, restart rate, commit rate. Under high work load （think time is ls） the miss rate of DMVOCC-MVDA is only 14.6%, is significantly lower than that of other protocols. The restart rate of DMVOCC-MVDA is only 32.3%, showing that DMVOCC-MVDA can effectively reduce the restart rate of mobile transactions. And the commit rate of DMVOCC-MVDA is up to 61.2%, which is obviously higher than that of other protocols.
文摘We have considered a method called Enhanced Rollback Migration Protocol, which potentially has the effects of compressing the period of compensations in a long-lived transaction, since before. In general, a compensation transaction can recover an irregular status of a long-lived transaction into the original status without holding unnecessary resources by making its consistency tentatively loose. However, it has also been pointed out that there is a difficulty of maintaining the isolation between a pair of transactions when executed in parallel. In particular, this could be more prominent under modernized scalable cloud environments. Thus, there is a proposal for concurrency control for the service level. However, there is still another risk that more computer resources will be consumed than actually necessary and an unnecessary stagnation of the processing will be caused if concurrency control is naively applied without careful consideration. Therefore, we need to implement a functionality which can optimize the processing of a long-lived transaction by selecting a suitable method between concurrency control and compensation transactions. In this paper, we propose a method in which optimistic concurrency control is applied for long-lived transactions. Furthermore, a pair of verification phases is carried out. At the beginning from a safe point, an attempt of verification is done. Then if the difficulty of isolation on a long-lived transaction executed under a competitive situation is estimated, concurrency control for the service level is applied. Alternatively, a long-lived transaction without any concurrency control is executed. At the next reachable safe point, another attempt of verification is performed. Then if a failure of serialization is detected, a set of compensation transactions is invoked to recover the original long-lived transaction by returning to the first safe point. We evaluated this approach by using numerical simulations and confirmed the basic features. This approach can realize optimizing and enhancing the performance of a long-lived transaction. We regard this approach applicable even to the modernized scalable cloud environments.
文摘As the representative of mature investors, security analysts＇ recommendations are guidance for most investors, However, a great deal of studies nearly draws the consistent conclusion, i.e. they are not as smart as we imagine, or the market doesn＇t trust their recommendations so much. The existence of optimistic bias in their recommendations has been supported by empirical data widely. Hence these make many papers to explore the reasons and try to give theoretical explanations. Based on prior researches, this paper mainly compares two theoretical models both based on mathematical methods.
文摘Regarding the global oil and gas market in 2018,some people are optimistic, others are worried, and it is fair to describe the market as complex and volatile. In his speech at the annual meeting of the Beijing Energy Club in mid-December 2018, Mr. Zhang Guobao.
文摘Cyber threats and risks are increasing exponentially with time. For preventing and defense against these threats and risks, precise risk perception for effective mitigation is the first step. Risk perception is necessary requirement to mitigate risk as it drives the security strategy at the organizational level and human attitude at individual level. Sometime, individuals understand there is a risk that a negative event or incident can occur, but they do not believe there will be a personal impact if the risk comes to realization but instead, they believe that the negative event will impact others. This belief supports the common belief that individuals tend to think of themselves as invulnerable, i.e., optimistically bias about the situation, thus affecting their attitude for taking preventive measures due to inappropriate risk perception or overconfidence. The main motivation of this meta-analysis is to assess that how the cyber optimistic bias or cyber optimism bias affects individual’s cyber security risk perception and how it changes their decisions. Applying a meta-analysis, this study found that optimistic bias has an overall negative impact on the cyber security due to the inappropriate risk perception and considering themselves invulnerable by biasing that the threat will not occur to them. Due to the cyber optimism bias, the individual will sometimes share passwords by considering it will not be maliciously used, lack in adopting of preventive measures, ignore security incidents, wrong perception of cyber threats and overconfidence on themselves in the context of cyber security.
文摘THE long-term rise in exports has made an undeniable contribution to China＇s economic growth. As the world＇s biggest commodities trader, China＇s reliance on foreign trade was the highest among the world＇s economic powers for many years.
文摘Forum on China-Africa Cooperation prepares for the next 10 years of development AFTER a decade of robust development, the Forum on China-Africa Cooperation (FOCAC),a mechanism bridging the world’s largest developing country and the world’s largest developing continent,is preparing for development in the next decade with great optimism.
文摘This year, the Fifth Ministerial Conference of the Forum on China-Africa Cooperation （FOCAC） will be held in China. Recently, Ambassador John Kayocle Shinkaiye, Chief of Staff, Bureau of the Chairperson of the African Union Commission （AUC）, shared his thoughts with ChinAfrica reporter Liu Wei on the role that FOCAC has played in strengthening Sino-African relations, at the AU headquarters in Addis Ababa, Ethiopia. His thoughts are as follows
文摘As an important fundamental industry of the national economy,the man-made fiber industrial chain is integrated into the era development and it assumes the responsibility of advancing.Each link of the industrial chain is connected with each other.After the development and accumulation of several decades,the new produced polyester,PTA and other plants keep
文摘THE recent World Bank report of the continent＇s economy, ＂Africa＇s Pulse＂ laid out a very optimistic path for 2012. Coming offthe back of an average 4.9 percent growth in 2011, Sub-Saharan Africa is poised for good economic times ahead,
文摘EACH new year promises much spirits are high, expectations large and friendships strengthened. By all accounts 2015 promises much for Sino-Affican cooperation. Admittedly, the threat of Ebola, as reported on extensively in this magazine during 2014, casts a pall of negativity and tragic consequences across the continent, most notably West Africa. This killer pandemic, coupled with the perennial threat of instability and terrorism that haunts Africa, poses the biggest threat to development and the economy of the continent this year. It is little wonder then that China and Africa acknowledge the need to tightencooperation in these areas.
