请输入或粘贴题目内容
搜题
拍照、语音搜题，请扫码下载APP
题目内容
（请给出正确答案）
A.had been put
B.were put
C.should be put
D.would be put
答案
更多“If the new safety system () to use, the accident would never have happened.()。”相关的问题
第1题
Like all large cities, New York has old problems to solve and【21】ones to face. Slums(贫民窟) must be cleared, and new housing constructed.【22】jams continues to plague(折磨) the city's overcrowded streets. Not only must new highways be【23】, but old ones must be repaired. Protecting the【24】and safety of New Yorkers【25】an army of police, firemen, and sanitation(卫生) workers. Finding an adequate water【26】is a constant problem, as is the attraction of new business and industry to boost the city's【27】. Caring for the sick,【28】the young, providing【29】the needy, and helping newcomers to adjust to big city life are additional tasks【30】the city must perform.
In spite of New York's【31】, millions of visitors continue to flock to the city each year. Thousands stay to work and【32】in the city,【33】to New York's human resources. New Yorkers are working hard to【34】their city's needs and to keep it a world【35】of culture, industry, and commerce. New York buzzes with the sounds of machines tearing down and building up the city, changing its face for tomorrow's world.
(41)
A．easy
B．hard
C．new
D．many
第2题
Software Security
软件安全
We live in a world today where software is pervasive. Software touches nearly every aspect of our lives, from software-controlled subways, air traffic control systems, nuclear power plants, and medical equipment to more mundane everyday examples, such as software-controlled microwave ovens, gas burners, elevators, automated teller machines[1], the family car, and the local 911 service[2]. In the past, many of these items relied upon established safety and reliability principles from electrical, mechanical, and/or civil engineering, which developed over several decades, if not longer. Today items like these are controlled by software.
When it is examined, its totality, the magnitude of the software safety and reliability challenge facing us today makes the Y2K[3]problem look minuscule by comparison. Hence, it is time to acknowledge the discipline of software safety and reliability and its importance to everyday life. Some people and organizations are starting to understand and respond to this challenge. For example, the FBI[4]recently established a National Infrastructure Protection Center to protect safety-critical systems and software. Unfortunately, many still remain blissfully unaware of the situation or deny its existence. Contributing to the problem is the small number of universities that offer courses in software safety and reliability.
We hear a lot about the global economy today. Technology has less respect for state or national borders than do market forces. The software safety and reliability challenge is a global challenge. Products, such as cars and medical devices, are built in one jurisdiction and sold worldwide. Air traffic control systems must interoperate safely and reliably among multiple countries, for example along the long borders between the U. S. , Canada, and Mexico. Accordingly, the first part of this book introduces the concept of software safety and reliability, and techniques and approaches used to achieve and assess it.
Background
The inherent complexity of software—its design, development, assessment, and use—is and has been increasing rapidly during the last decade. The cycle time between new versions of system and application software has decreased from a number of years to a number of months. The evolution and discovery of new design techniques and development methodologies are proceeding at an equally rapid pace. Consequently, the debate about what constitutes the standard body of knowledge for Computer Science professionals continues.
Accompanying this is the ever broadening role that software plays in electronic products. A study performed in the U. K. in 1990 estimated that the market for the development of safety-related software was ＄. 85B per year and that it was growing at a rate of 20 percent per year. This is due to the fact that software is replacing discrete hardware logic in many devices. Some common examples include air traffic control systems, nuclear power plant control systems, and radiation therapy systems. In addition, advanced electronics with embedded software controllers are being incorporated into a variety of new products, such as laser surgical devices, automobiles, subways, and intelligent transportation systems.
As such the role of software has moved from simply generating financial or other mathematical data to monitoring and controlling equipment, which directly affects human life and safety. In fact, it was reported by Donald Mackenzie that "the total number of people killed by computer system failures, worldwide, up to the end of 1998 is between 1,000 and 3,000. "
As a result, a more thorough and widespread understanding of, and familiarity with the specialized techniques to achieve and assess the safety and reliability of software, are needed in academia, industry, and government. This is also true since many legal issues related to software liability are evolving.
Purpose
While the general concept of safety and reliability is understood by most parties, the specialty of software safety and reliability is not. The understanding of electronic component reliability and electrical safety has been evolving since the 1940s. In contrast, software safety and reliability is a relatively new discipline that only a few understand well or at all. Hence, the overall goal of writing this book is to improve the state of the art of software safety and reliability, both its understanding and practice. This goal is achieved through three objectives.
The first objective of this book is to serve as a "consciousness raising"[5]about the importance of software safety and reliability and the attention this subject warrants in mission critical systems[6]. As more and more functionality is shifted from hardware to software, two common scenarios occur. First, managers and technical personnel involved in mission critical projects are generally very knowledgeable about optics, radiation physics, mechanical engineering, and so forth. However, they are sometimes at a loss when it comes to knowing: 1) what to do about software safety and reliability; 2) the skill set that is needed to adequately address software safety and reliability; and 3) sometimes even that this subject warrants serious attention. Second, today there are many excellent Computer Science and Software Engineering programs at universities throughout the worlＤ. Unfortunately, very few of them offer any courses on software safety and reliability or on software engineering standards. A student may acquire a thorough background in software engineering without being exposed to the field of software safety and reliability. Given the shift in technology to software controlled products, this is unfortunate because today's students will be tomorrow's safety and reliability practitioners. This book has been written to serve as a "consciousness raising" for both scenarios. As such, it includes many illustrative everyday examples about the importance of software safety and reliability.
The second objective of this book is to provide practical information about the current methods used to achieve and assess software safety and reliability. This is accomplished by a comprehensive discussion of the current approaches promoted by key industrial sectors and standards organizations to software safety and reliability. Since most practitioners were not taught software safety and reliability in school, it is all the more imperative that they be made aware of current software safety and reliability standards[7]. As a rule, standards are written in a very terse style. A phrase or sentence may be very meaningful to the committee members who spent years writing the standard, but the same phrase leaves the average reader in the dark. Accordingly, Parts Ⅱ and Ⅲ of this book have been written in the style of an application guide—" how to" read, interpret, and implement a given standarＤ. While theory is not entirely neglected, the emphasis is on practical information.
The third and final objective of this book is to bring together, for the first time, in one volume the contemporary thinking on software safety and reliability so that it can be compared and analyzed; thereby leading to the improved understanding and practice of this field in the future.
Firewall
Nations without controlled borders cannot ensure the security and safety of their citizens, nor can they prevent piracy and theft. Networks without controlled access cannot ensure the security or privacy of stored data, nor can they keep network resources from being exploited by hackers.
The communication efficiency provided by the Internet has caused a rush to attach private networks directly to it. Direct Internet connections make it easy for hackers to exploit private network resources. Prior to the Internet, the only widely available way for a hacker to connect from home to a private network was direct dialing with modems and the public telephone network. Remote access security was a relatively small issue.
When you connect our private network to the Internet, you are actually connecting your network directly to everv other network attached to the Internet. There's no inherent central point of security control.
Firewalls are used to create security checkpoints at the boundaries of private networks. By providing the routing function between the private network and the Internet, firewalls inspect all communications passing between the two networks and either pass or drop the communications depending on how they match the programmed policy rules. If your firewall is properly configured and contains no serious exploitable bugs, your network will be as free from risk as possible.
Firewalls are among the newest developments in Internet technology. Developed from rudimentary security systems that major computer vendors like Compact and IBM developed to secure their own networks in the mid 1980s, these network sentinels have developed in lock-step with the burgeoning threat of information warfare. The most interesting and innovative developments, like Network Address Translation and multi-layer security filtering, are so new that books just two years old are already obsolete.
The security problems of the past could be solved with simple packet filters and dial- back modem banks. The security problems of the future will require rifling through and validating every byte of an Internet message, requiring encrypted certification of a web site's true identity before connecting, and then encrypting nearly everything that travels between. Fortunately, as technology and the technological society it mirrors progress, these measures will become simple and invisible. As vendors make operating systems more hardened against attack, the World Wide Web will secretly grow more secure for people who will freely surf the Web as they please, hampered only by the occasionally warning that a site is not accredited or that a message contains suspicious content. This is as it should be.
The security problems of today are most effectively solved with firewalls and virtual private tunnels. Peripheral security utilities[8]like intrusion detectors and security scanners do their part to alarm and alert, but firewalls will remain the foundation of Internet security until their functionality is built into the very protocols upon which the Internet operates and until every Internet-connected computer contains the equivalent of a firewall. Even then, centralized management of Internet policy may make firewalls a permanent addition to corporate networking.
Notes
[1]automated teller machines：自动取款机，简写成ATM。
[2]911 service：在美国等一些西方国家，紧急救护号码为9ll。
[3]Y2K(Year 2000)：电脑千年虫。
[4]the FBI：(美国)联邦调查局(Federal Bureau of Investigation)的缩写。
[5]consciousness raising：提高意识。
[6]mission critical systems：任务是至关重要的系统。
[7]It is...从句中用should+do，should常可省，如：It is important that he start early tomorrow.
[8] Peripheral security utilities: 外围(部)安全设备。
Choose the best answer:
第3题
确定以下各个文献书目信息的iPAC题名关键词字段的检索策略：
①孙乃修．屠格涅夫与中国[M]．上海：学林出版社，1988
②Burtless G，Greenberg D．Measuring the Impact of NIT Experiments on Work Effort[J]．Industrial and Labor Relations Review，1983，36(4)：592—605
③唐咏雪．广告标示语注意力吸引策略与最佳关联研究．商业理论周刊[J]，1999，12(5)：11-13
④Harold E R，Moriarty B．System safety engineering and management[M]．2nd ed．1990，New York：Wiley
⑤金赛波．美国法上信用证欺诈与禁令[C]．沈四宝主编．国际商法论丛，北京：法律出版社，1999
⑥ Tillinghast D R. The Choice of Issues to be Submitted to Arbitration under Income Tax Conventions [C]. Alpert, Herbert H. ed., Essays on International Taxation, New York: Kluwer, Law and Taxation Publishers, 1993
⑦ Hendrik B, Luc D. On the Stability of Example-Driven Learning Systems: A Case Study in Multirelational Learning [C]. Carlos A C ed., MICAI 2002: Advances in Artificial Intelligence, volume 2313 of Lecture Notes in Artificial Intelligence, pages 321 - 330. New York: Springer-Verlag, April 2002
⑧吴敬琏著．大中型企业改革：建立现代企业制度[M]．天津人民出版社，1993
⑨王通讯．WTO与人事人才工作[J]．人事决策参考，2001,15(3). 259-261
第4题
【C1】
A．whereas
B．as
C．though
D．so
第5题
Does this sound familiar？ You have probably read something like it in magazines or books, or seen it in a film. Why is it so popular？ One of the reasons is that it reflects the fears of many people; fear of the unknown fear of what is not understood or, at least, fear of something that is not completely understood.
The fact is that every day it seems that computers take control of another area of our lives. Some
factory jobs are now done by robots and the robots are controlled by computers. Our bank accounts are managed by computers. At the airport, our tickets are sold by a computer. Certainly, many of these operations are made more
efficient by computers, but our admiration is sometimes mixed with unsafe feelings. And this lack of safety is caused by the fact that we do not know how computers do these things, and we really don't know what they might do next. But we can find out how computers work, and once we understand them, we can use computers instead of worrying about being used by them. Today, there is a new generation of computer wizards who know exactly how computers get things done. These young men and women, usually university students, are happy to sit for hours, sometimes for days, designing programs, not eating, not sleeping, but discovering what can be done by these wonderful slaves which they have learned to control. These computer wizards have learned to use the computer and search for new tasks for their machines.
(1)、According to the passage, our present world is under the control of ______ .
A：mad scientists
B：men and women
C：the unknown fear
D：some super-inventions
(2)、The reason why many people are afraid of computers is that ______ .
A：they don't know anything about computers
B：they haven't really understood computers
C：there are so many computer games
D：computers are often down
(3)、The author mentions computer wizards in order to point out that ______ .
A：computers can be controlled by man
B：there should be more people devoted to computers
C：only young people are interested in computers
D：more time and energy is required to control computers
(4)、This passage is probably written to suggest that ______ .
A：some day computers can deal with all human problems
B：computers can be used in place of traveling to our jobs
C：people should not fear computers
D：computer technology will not meet people's needs in various situations
(5)、The author's attitude towards widely used computers is __.
A：positive
B：anxious
C：worried
D：serious
第9题
A.secure
B.security
C.safety
D.save
第10题
职业安全与健康管理局(Occupational Safety and Health Administmtion，OSHA)
