超级军网发个帖子吧——从书上看来的
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Does the choice of real number representation really make a difference in
our applications? “On February 25, 1991, a Patriot missile defense system
operating at Dhahran, Saudi Arabia, during Operation Desert Storm failed
to track and intercept an incoming Scud [missile]. This Scud subsequently
hit an Army barracks, killing 28 Americans” (Blair et al., 1992). The Patriot
battery failed because of a software problem related to the storage and use
of floating point numbers. The system stored time, in tenths of a second, in
a floating point variable. Table 2.1, taken from the Government Accounting
Office report, shows the magnitude of the error in representing this time
as a floating point value. As with all floating point representations, the
magnitude of the error increases with the magnitude of the value.
Absolute Approximate shift in
Time inaccuracy missile range gate
Hours Seconds (seconds) (meters)
0 0.0 0.0 0
1 3600.0 0.0034 7
8 28800.0 0.0275 55
20 72000.0 0.0687 137
48 172800.0 0.1648 330
72 259200.0 0.2472 494
100 360000.0 0.3433 687
Table 2.1 Magnitude of range gate error when modeling time as a floating
point real numberDoes the choice of real number representation really make a difference in
our applications? “On February 25, 1991, a Patriot missile defense system
operating at Dhahran, Saudi Arabia, during Operation Desert Storm failed
to track and intercept an incoming Scud [missile]. This Scud subsequently
hit an Army barracks, killing 28 Americans” (Blair et al., 1992). The Patriot
battery failed because of a software problem related to the storage and use
of floating point numbers. The system stored time, in tenths of a second, in
a floating point variable. Table 2.1, taken from the Government Accounting
Office report, shows the magnitude of the error in representing this time
as a floating point value. As with all floating point representations, the
magnitude of the error increases with the magnitude of the value.
Absolute Approximate shift in
Time inaccuracy missile range gate
Hours Seconds (seconds) (meters)
0 0.0 0.0 0
1 3600.0 0.0034 7
8 28800.0 0.0275 55
20 72000.0 0.0687 137
48 172800.0 0.1648 330
72 259200.0 0.2472 494
100 360000.0 0.3433 687
Table 2.1 Magnitude of range gate error when modeling time as a floating
point real number
our applications? “On February 25, 1991, a Patriot missile defense system
operating at Dhahran, Saudi Arabia, during Operation Desert Storm failed
to track and intercept an incoming Scud [missile]. This Scud subsequently
hit an Army barracks, killing 28 Americans” (Blair et al., 1992). The Patriot
battery failed because of a software problem related to the storage and use
of floating point numbers. The system stored time, in tenths of a second, in
a floating point variable. Table 2.1, taken from the Government Accounting
Office report, shows the magnitude of the error in representing this time
as a floating point value. As with all floating point representations, the
magnitude of the error increases with the magnitude of the value.
Absolute Approximate shift in
Time inaccuracy missile range gate
Hours Seconds (seconds) (meters)
0 0.0 0.0 0
1 3600.0 0.0034 7
8 28800.0 0.0275 55
20 72000.0 0.0687 137
48 172800.0 0.1648 330
72 259200.0 0.2472 494
100 360000.0 0.3433 687
Table 2.1 Magnitude of range gate error when modeling time as a floating
point real numberDoes the choice of real number representation really make a difference in
our applications? “On February 25, 1991, a Patriot missile defense system
operating at Dhahran, Saudi Arabia, during Operation Desert Storm failed
to track and intercept an incoming Scud [missile]. This Scud subsequently
hit an Army barracks, killing 28 Americans” (Blair et al., 1992). The Patriot
battery failed because of a software problem related to the storage and use
of floating point numbers. The system stored time, in tenths of a second, in
a floating point variable. Table 2.1, taken from the Government Accounting
Office report, shows the magnitude of the error in representing this time
as a floating point value. As with all floating point representations, the
magnitude of the error increases with the magnitude of the value.
Absolute Approximate shift in
Time inaccuracy missile range gate
Hours Seconds (seconds) (meters)
0 0.0 0.0 0
1 3600.0 0.0034 7
8 28800.0 0.0275 55
20 72000.0 0.0687 137
48 172800.0 0.1648 330
72 259200.0 0.2472 494
100 360000.0 0.3433 687
Table 2.1 Magnitude of range gate error when modeling time as a floating
point real number
龙芯爬过……
看不懂
有这种案例？
这下，测试和QC课的老师 上课时又可以灌水说故事啦
这下，测试和QC课的老师 上课时又可以灌水说故事啦
啥鸟文？对不起，我不在纽约
没什么意思，软件设计缺陷
what the f_{:soso__1514282355054914221_2:}
what the f_{:soso__1514282355054914221_2:}
下一部分
Table 2.1 shows that the floating point representation error grows as the
number grows. After 20 hours, the time is off enough that the target is
outside the range gate and the Patriot missile fails to launch against a threat.
After the tragedy, the software was corrected by replacing the floating point
time variables with fixed point variables.
Table 2.1 shows that the floating point representation error grows as the
number grows. After 20 hours, the time is off enough that the target is
outside the range gate and the Patriot missile fails to launch against a threat.
After the tragedy, the software was corrected by replacing the floating point
time variables with fixed point variables.
TNND! 啥意思嘛 请说普通话好吗
请不要讲方言，请讲普通话，谢谢！
由此看来，爱国者早期型确实够水的
楼主附带上一文可以吗？我静不下心来看鸟文，环境很吵。
表示不想看！
最讨厌这种贴！欺负淫不懂方言不是！
what意思？没看懂哈，整点大爱能看明白的，这年头没文化真可怕，自以为有文化更可怕
我操，这不是在考验我们智商吗？拿外国方言来让我们中国人看，楼主怎么不弄玛雅文，写的时候在写2012不是世界末日。