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最大需量有哪两种计算方式？两者之间有何区别？

答案

参考答案：

最大需量有区间式和滑差式这两种计算方式，两者之间区别在于：

（1）区间式最大需量计算方式：将第1min到第15min的脉冲数累加后乘以脉冲的电能当量（指每个脉冲所代表的电能值），再除以15min，即得到需量值P1，保存于最大需量的存储单元中，然后进行第16min到第30min需量区间的计算，将第二次计算值P2与P1比较，若P2>P1，则将P2取代P1存于最大需量的存储单元中，依次类推，最大需量的存储单元中始终保持15min平均功率的最大值。

（2）滑差式最大需量计算方式：将第1min到第15min的脉冲数累加后乘以脉冲的电能当量（指每个脉冲所代表的电能值），再除以15min，即得到需量值P1，保存于最大需量的存储单元中，第二次计算需量值时，是从第（1+t）min到第（15+t）min内计算平均功率，其中t为滑差区间的时间。第n次计算，依次类推，即从第（1+nt）min到第（15+nt）min内计算平均功率，每次将计算值进行比较保存最大值于最大需量的存储单元中。

单项选择题


With 2005 fast becoming "the year of the natural disaster", it is time to reflect on how engineering, science and technology can play their fullest part in protecting the planet.
Long before the Asian tsunami struck, the science community predicted the particular region of Indonesia to be hit by the next big earthquake; and the engineering and technology community had developed early warning systems costing only ＄ 30 million. But no government in the region heeded the warnings and no early warning systems were in place. We ignored technology of the advance warnings at our peril of 100,000 victims of the tsunami.
Governments are not alone in ignoring the views of their scientific community; the public too has its doubts. Part of the reason for this lack of confidence must be down to the failure to engage them in a meaningful way about their concerns. Trust is a two-way street. Instead of claiming that everything would be rosy in the scientific garden "if only the public understood", we must work hard to explore concerns, discover fears and delve deep into the depths of public perceptions. We are getting there. There is a growing realization that effective public engagement is of far greater value than banging the "public understanding" drum.
There are still doubters, of course, and sadly their cause is helped whenever they come across opinions presented as fact. All of us must guard against this debilitating practice. In time, effective public engagement should help deliver improved trust as well as better policy, which -- in turn -- might make it more difficult for scientists’ warnings to be ignored.
Today’s technology community is a triumph of international collaboration where engineers and scientists combine to develop solutions to our biggest problems. Of course, technology cannot stop natural disasters but it can mitigate their impact. We are able to identify the birds affected by avian flu. We can chart their migration patterns around the world. We have the means to pursue vaccines. And we have the communication channels to keep people informed.
Extolling the virtues of technology is not to pretend technology is perfect in every regard. Far from it. The profligate and unsustainable use of technology in energy and transport has contributed to climate change. But that doesn’t mean technology has failed us. We must never lose sight of the fact that technology itself will deliver the solutions to the very problems it can create. If we do, technology will remain sidelined and undervalued, and this major social failure will progressively disadvantage us all.
Our vision is of a society embracing technology as a weapon of both progress and defense. Since the beginning of civilization, we have relied on it and enjoyed its benefits -- and most new technologies have had hugely beneficial effects for most people. But now, in an age when the death toll from natural disasters is increasing year on year, with more people living in danger zones, it is ever more urgent that we rely on science and technology to warn us of the dangers to come and provide the solutions we need.

"The Year of the Natural Disaster" tells us that ______.

A．we suffered a lot in recent years

B．engineering, science and technology can play their important part

C．Asian Tsunami caused death of 100,000 victims

D．no government paid enough attention to the early warnings
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单项选择题

下列哪个参数与统一眩光值(UGR)的计算式无关( )

A．观察者方向每个灯具中光源的发光强度

B．背景亮度

C．观察者方向每个灯具的亮度

D．每个灯具的位置指数
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