A small group of Internet security special

题型:单项选择题

问题:

A small group of Internet security specialists gathered in Singapore to start up a global system to make e-mail and e-commerce more secure, end the rapid growth of passwords and raise the bar significantly for Internet fraud, spies and troublemakers.

The Singapore event included an elaborate technical ceremony to create and then securely store numerical keys that will be kept in three hardened data centers there, in Zurich and in San Jose, Calif. The keys and data centers are working parts of a technology known as Secure DNS, or DNSSEC. DNS refers to the Domain Name System, which is a directory that connects names to numerical Internet addresses. Preliminary work on the security system had been going on for more than a year, but this was the first time the system went into operation, even though it is not quite complete.

The three centers are fortresses made up of five layers of physical, electronic and cryptographic security, making it virtually impossible to damage the system. Four layers are active now. The fifth, a physical barrier, is being built inside the data center.

The technology is viewed by many computer security specialists as a ray of hope amid the recent cascade of data thefts, attacks, disruptions and scandals, including break-ins at Citibank, Sony, Lockheed Martin, RSA Security and elsewhere. It allows users to communicate via the Internet with high confidence that the identity of the person or organization they are communicating with is not being tricked or forged.

Internet engineers like Dan Kaminsky, an independent network security researcher who is one of the engineers involved in the project, want to counteract three major deficiencies in today’s Internet. There is no mechanism for ensuring trust, the quality of software is uneven, and it is difficult to track down bad actors.

One reason for these flaws is that from the 1960s through the 1980s the engineers who designed the network’s underlying technology were concerned about reliable, rather than secure, communications. That is starting to change with the introduction of Secure DNS by governments and other organizations.

The event in Singapore capped a process that began more than a year ago and is expected to be complete after 300 so-called top-level domains have been digitally signed. Before the Singapore event, 70 countries had adopted the technology, and 14 more were added as part of the event. While large countries are generally doing the technical work to include their own domains in the system, the association of Internet security specialists is helping smaller countries and organizations with the process.

It is suggested in Paragraph 4 that()

A. the Net security system has protected lots of companies from data thefts

B. scientists sees the Net Security System as a promising technology

C. companies like Sony are undergoing an Internet security crisis

D. communication via the Internet makes people more confident

考点:普通考研考研数学(二)考研数学二
题型:单项选择题

小词能不能在文字里蕴含丰富的情意感发和联想,作用都是从下列哪一项产生的()。

A.用典

B.节奏

C.语言文字

D.平仄

题型:单项选择题

把下面各数四舍五入到“万”位或“亿”位.

89900043058002680063005

349800038040008728531089520.

题型:单项选择题

如图是人体血液循环示意图,其中A,B,C,D代表心脏的四个腔,箭头代表血流方向.请根据图回答下列问题.

(1)进餐1小时后,与①处相比,②处血液中营养物质含量的变化是______(填“增多”、“减少”或“不变”).

(2)血液流经“B→⑤→肺→⑥→C”的循环途径称为______;经过该循环途径,血液性质发生的变化是______.

(3)血液流经肾脏后,④处血液中尿素的含量与③处相比______(填“增多”或“减少”).

(4)2012年“毒胶囊”事件被媒体曝光,不法企业制作毒胶囊的原料是从废旧皮鞋中提取出的工业明胶,重金属铬的含量严重超标.铬对人体健康有严重危害,铬进入人血液后,可透过红细胞膜与血红蛋白结合,从而降低了红细胞______功能.

题型:单项选择题

中小学教学楼过道宽度外廊为()mm。

A.1500

B.1600

C.1800

D.2000

题型:单项选择题

某企业目前的资金结构为长期借款1600万元,年利率10%;权益资金2400万元,股数200万股,上年支付的每股股利2元,预计股利增长率为5%,目前价格为20元,企业目前的销售收入为2000万元,变动成本率为50%,固定成本为200万元,该企业准备扩大生产规模,计划筹集资金200万元,预计投产后企业会增加400万元的销售收入,变动成本率仍为50%,固定成本增加40万元,企业所得税率为40%,现有两种筹资方案可供选择。

方案一:增加长期借款200万元,借款利率上升到12%,股价下降到19元,假设企业其他条件不变。

方案二:增发普通股8万股,普通股市价增加到每股25元,假设公司其他条件不变。

 

分别计算采用方案一和方案二后的加权平均资金成本、经营杠杆系数、财务杠杆系数和复合杆系数。

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