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[已翻译,待校对] [SETI] 实时的信号分析 Analyzing Signals in Real Time

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发表于 2013-2-22 16:25:47 | 显示全部楼层 |阅读模式
来源:wiki未翻译文献,砍掉重练。
原载http://www.planetary.org/blogs/g ... thome_20050707.html
概要:不知道

文章没读,不保证标题翻译准确,请自行斟酌。
有愿意帮助翻译的,请直接回帖(可以先占座,再翻译或编辑)

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参与人数 1维基拼图 +8 收起 理由
昂宿星团人 + 8 发布原文

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发表于 2013-2-22 18:09:48 | 显示全部楼层
标题也许是:分析现实中的信号
没时间翻译文章,只是读了一遍原文,仅供参考……
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发表于 2013-4-1 22:13:17 | 显示全部楼层
本帖最后由 shmetrofans 于 2013-4-6 17:47 编辑

好吧,那我帮忙翻译一下
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发表于 2013-4-21 10:20:04 | 显示全部楼层
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发表于 2013-4-30 21:57:42 | 显示全部楼层
翻译日志

2013/04/30  发布!
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发表于 2013-4-30 22:03:53 | 显示全部楼层
译序

本文从SETI@home志愿者关心他们找到的信号是否为真的 E.T. 信号开始,介绍了 SETI@home 项目组最初要六个月集中处理一次的做法,现在(2005年)已经难以为续。为此,SETI@home 项目组提出了“近乎实时的持续信号检测器(Near Time Persistency Checker)”,可以立即判断志愿者提交的候选信号,是否为真的 E.T. 信号。
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发表于 2013-4-30 22:16:45 | 显示全部楼层
Analyzing Signals in Real Time
实时分析信号

原文:http://www.planetary.org/blogs/guest-blogs/amir-alexander/setiathome_20050707.html

第一段
For years you have been a loyal SETI@home user, searching for that elusive extraterrestrial signal at every idle moment your computer could spare. You have processed hundreds of work units and returned thousands of potential candidate signals back to SETI@home headquarters. But never yet have you seen anything resembling the “Real Thing.” Until now. There, flashing on your screen is a beautiful gaussian, as clear and crisp as anything a SETI scientist could have dreamt up. Could it be that after all these years you have just detected a signal from E.T.?
你是一名酒精考验的“在家搜索外星人(SETI@home)”志愿者,你利用计算机的空闲周期,参与搜索那飘渺的地外信号。你已算完了数百个任务单元,并且把数千个潜在的候选信号,返回给SETI@home。但直到现在,你也没见过任何“实物”。你屏幕上闪现的是,漂亮的高斯方程计算过程,但那只是 SETI@home 科学家梦寐以求的东西。这些年来,它真的帮你检测到一个E.T信号吗?

第二段
With your heart pounding you rush to your computer and send urgent messages to SETI@home or The Planetary Society. “A BIG signal is heading your way!” you write breathlessly. “Could you please be sure to process it quickly? It just might be the signal we’ve been waiting for...” Sadly, the SETI@home crew appears surprisingly unaffected by your excitement. “Your candidate signal has been received and stored in our data-base” you are told calmly, “and will be analyzed within six months.” They promise to be in touch if it proves to be strong candidate for an extraterrestrial signal. And that is that.
你心慌意乱、跌跌撞撞地奔向计算机,屏住呼吸向 SETI@home 或行星协会发送紧急信息:“史上最重要的信号就在你面前!请问你们能否快点处理它?它可能就是我们一直苦苦寻找的信号。”让人难过的是,SETI@home项目组的成员,对你的兴奋心情无动于衷。他们平静地告诉你:“你的候选信号已经收到,现已储存在我们的数据库中,并在六个月内处理。”,他们还承诺,如果你发现的信号被证实有可能是外星人的信号,就会与你联系。然后就完了。

第三段
The magic moment passes, the months go by, and no word arrives from SETI@home. Your original enthusiasm has greatly subsided, but once in a while you still wonder about that unexplained gaussian: “could it have been the Real Thing? and if not, what was it?” You realize that you may never know the answer�
梦醒之后,转眼又过了数月,SETI@home 没有只言片语传来。你当初的激情早已平复,可一旦你想起那个令人费解的高斯方程,还是禁不住要问:“它确实是个真实的‘东西’吗?如果不是,那又是什么玩意?”你意识到,你可能永远无法知道答案。

第四段
So it has been for many dedicated SETI@home users, who have occasionally run across promising-looking patterns in their work units. As members of the SETI@home team often explain, they cannot analyze a candidate signal � even the most promising one � at the time that it comes in. This is because a candidate signal does not stand by itself. It has to be confirmed by other signals coming from the same point in the sky at the same frequency, but measured at different times. “Signals are constantly coming in from clients” explains SETI@home Project Scientist Eric Korpela, “and they build up in a data base. “Every six months or so we sift through what we have,” ranking the different candidates and locating the most promising ones.”Then, when the opportunity arises, the SETI@home crew revisits the strongest candidates with a radio telescope, looking for a repeat performance (i.e., a consistent signal).
类似的情况发生在很多SETI@home的志愿者身上,他们在曾经任务包中,偶尔发现看上去很有希望的信号(patterns)【译注4-1】。正如 SETI@home 的组员经常解释的那样,他们无法在候选信号出现的时候,及时进行分析,哪怕是最有可能的信号也不行。因为候选信号无法自证。必须有来自太空同一点、同一频率、不同时刻的其它多个信号,才能证明这是个有效信号。“我们不断收到客户端提交的信号,” SETI@home 项目中的科学家埃里克•科尔佩拉(Eric Korpela)说道:“只能先存入数据库。大约每隔六个月,筛选一次这段时间积累的信号,并对不同的候选信号进行分级,以锁定最有可能的信号。”然后,当机合适时,SETI@home 的成员会把射电望远镜对准最有可能的信号源,寻找重复出现的信号(比如一个连续信号)。
【译注4-1】pattern 在匹配中是“样板”的意思,所以,原文应指“找到匹配信号”。


第五段
“This system,” explains Korpela, “worked well as long as we had only millions of candidate signals to work with.” Such was the case with SERENDIP, the sky survey project that spawned SETI@home. Now, however, after six years of SETI@home, with millions of users processing and returning data, the candidate signals list is approaching 2 billion! With such an enormous � and fast growing � amount of data to process, a program that only analyzes the data every six months runs the risk of falling further and further behind.
“这个系统,”科尔佩拉解释道:“一直运作良好,已经处理了数百万的候选信号。”巡天项目 SERENDIP 的情况就是这样,它催生了 SETI@home。【译注5-1】但是,现在离 SETI@home 项目启动已过去六年,数百万志愿者计算并传回的数据,使候选信号表的长度接近 20 亿!如此巨大,并且还在快速增长的数据量需要处理,每六个月才运行一次程序来分析数据,这样做迟早会出事。
【译注5-1】搜寻来自近地外智慧生命群落的无线电波计划(Search for Extraterrestrial Radio Emissions from Nearby Developed Intelligent Populations,缩写SERENDIP) 是一个搜索地外生命(SETI)项目,由加州大学伯克利分校举办。

http://en.wikipedia.org/wiki/SERENDIP
http://zh.wikipedia.org/wiki/%E6%90%9C%E5%AF%BB%E6%9D%A5%E8%87%AA%E8%BF%91%E5%9C%B0%E5%A4%96%E6%99%BA%E6%85%A7%E7%94%9F%E5%91%BD%E7%BE%A4%E8%90%BD%E7%9A%84%E6%97%A0%E7%BA%BF%E7%94%B5%E6%B3%A2%E8%AE%A1%E5%88%92

第六段
And so Korpela, working closely with Chief Scientist Dan Werthimer and Software Engineer Jeff Cobb, came up with a new plan: Real Time Analysis of incoming signals. According to this new method, candidates sent in by users around the world will be quickly analyzed and compared to existing signals. Their promise of being a true E.T. signal will be quickly evaluated, almost in real time.
因此,科尔佩拉与首席科学家丹•沃西默【译注6-1】、软件工程师杰夫•科布密切合作,构思出一个新的计划——实时分析志愿者提交的信号。根据这种新方法,全球志愿者发来的候选信号,将被迅速分析,并与已知信号对比。他们承诺,会迅速评估是否为E.T.信号,快到近乎实时。
【译注6-1】沃西默是词海(http://dict.cn/Werthimer)给出的翻译,另外一个“魏茨莫”是有道(http://dict.youdao.com/w/dan_werthimer/)的翻译。因为词海的翻译与google的发音相近,故被采纳。

第七段
How will this be possible? Cobb explains: the entire surface of the sky will be divided into 50 million unique “pixels,” creating a virtual map of the heavens. Every candidate signal sent by users will be tagged with a unique number called a “cubic pixel” (“qpix”) number, which will indicate precisely in which pixel in the sky it was detected, and at what frequency. That unique pixel in the sky-map will then become a “hot spot,” indicating that a new signal has been detected at that location. The signal itself, along with its qpix number, will then be stored in the data base.
这怎么可能?科布解释说,整个天球的表面【译注7-1】被分为5千万个不重叠的【译注7-2】“点”,勾画出一幅虚拟的天体图(map of heavens)【译注7-3】。志愿者提交的每一个候选信号,都用一个独一无二的编号,作为识别码。我们把这个编号称为“方块点”(读作乔比斯,qpix),它可以精确指出发现信号的天空位置,以及信号出现的频率。发现信号的地方,就成了天体图上的“热点”,说明该点侦测到一个新的信号。而信号连同它的乔比斯点,随后被存入数据库。
【译注7-1】参见http://www.equn.com/forum/forum.php?mod=redirect&goto=findpost&ptid=32977&pid=435359
【译注7-2】unique的原意是独一无二。我认为天球就像足球一样,每块区域之间没有重叠。
【译注7-3】天体图的说法参见http://setitaiwan.tripod.com/MIRROR/reference/index.htm

第八段


The rest of the work, said Cobb, will be done by a program he calls the “Near Time Persistency Checker,” which will be running continuously as new signals are entered into the data base. It will zero in on the “hot spots” where new candidate signals have been identified, and compare the new signals with any others that have previously been identified at the same spot. The program will then determine whether the new data warrants an increase in score for that particular location, a decrease, or no change. As its name suggests, the most crucial factor the Near Time Persistency Checker will be analyzing is persistency � whether a signal has already been detected at that point in the past at the same or a close frequency. Other factors include the strength and shape of the signal.
科布说,剩下的工作将交由他称作“近乎实时的持续信号检测器”【译注8-1】完成。这个程序会一直运行,即使是新信号已被存入数据库。它还负责调整(zero in)发现新候选信号的“热点”:把新信号与以前在同一点发现的其它信号相比较,以决定是为该点加分、减分,还是保持不变。正如程序的名字“近乎实时的持续信号检测器”所说,它要分析的最关键因素是持续性——与信号相同或相近的频率,是否在过去被发现过。其它因素包括,信号强度以及信号波形。
【译注8-1】

http://www.equn.com/wiki/SETI@home#Near_Time_Persistency_Checker_.28NTPCKR.29.EF.BC.88.E6.8C.81.E7.BB.AD.E4.BF.A1.E5.8F.B7.E7.9A.84.E8.BF.91.E5.AE.9E.E6.97.B6.E6.A0.A1.E6.A3.80.EF.BC.89
http://setiathome.berkeley.edu/ntpckr_faq.php

第九段
Since the Near Time Persistency Checker will be running constantly, the rankings of the different candidate signals will also be updated constantly. “We won’t have to do a massive analysis of all the data every six months in order to come up with a list of the top candidates,” explained Cobb, “because that list will now be generated automatically.” Before the Arecibo reobservations in 2003, for example, the SETI@home crew spent months analyzing the data to come up with a list of the 200 most promising candidates. Once the new approach is implements, this will no longer be necessary: the list, and the rankings, will be continuously generated every single day.
由于“近乎实时的持续信号检测程序”一直运行,不同候选信号的级别也会不断更新。科布说:“我们再也不必为了列出优先级最高的(top)信号表,每六个月对全部数据做一次大量的分析,因为那张表现在可以自动生成了。” 例如,阿雷西博天文台 2003 年再次开机观察之前, SETI@home 组员就花了数月时间分析数据,以找出 200 个最有可能是真的候选信号。一旦新办法得以实施,就不再需要这样做了。将来,每一天都会生成列表,并且分好级。

第十段
The conceptual breakthrough that makes this possible, according to Korpela and Cobb, is the ability to assign a single “qpix” number to a candidate, which indicates its location in the sky and frequency. This, explained Cobb, makes it possible to search through the database extremely quickly, and match the appropriate old and new signals with each other. Without the “qpix,” the search would have to be done according to three different parameters � the celestial coordinates and the frequency. This would have made real time analysis so complex as to make it practically impossible.
据科尔佩拉和科布介绍,使这成为可能的概念性突破,是给候选信号分配一个独一无二的,并能标记信号在天体图位置,以及频率的“乔比斯”编号的能力。科布进一步解释说,“乔比斯”编号能以极快的速度搜索整个数据库,并找出相互匹配的新老信号。没有乔比斯编号,查找工作只能依靠三个不同的参数完成:天体坐标和频率【译注10-1】。如此,使得实时分析复杂到难以实现。
【译注10-1】天体坐标显然包括经度和纬度两个参数。


第十一段
Even so Cobb cautions: “We are still in the proof-of-concept stage for this approach. There may be roadblocks ahead that we had not considered.” But if all goes well, Korpela and Cobb hope to have the system running within a few months, analyzing all SETI@home signals as they come in.
即使如此,科布还是提醒大家:“我们的方法还处在‘概念验证(proof-of-concept)’的阶段。以后可能还有我们意想不到的困难。”但如果一切顺利,科尔佩拉和科布希望,系统能在未来数月投入运行。到时候,只要一有SETI@home信号进来,就能立即对它进行分析。

第十二段
And what of the SETI@home user who thought he saw something but never knew what became of the promising gaussian? He or she will not have to wait any longer. Once real time analysis is implemented, the SETI@home team hope to have a running ranking of the different signals on the website, together with the users who contributed to each candidate. Curious users will simply go to the list to find out the fate of “their” signal. It may simply be a test signal, or radio interference; but it may, just possibly, be the Real Thing
那么,那些自认为看到了什么,却从不知道高斯方程意味着什么的 SETI@home 志愿者,他们到底看到了什么东西?他们再也不必苦苦等待了。一旦实现实时分析,SETI@home 团队希望建立一个网站,对不同信号进行分级,并向那些找到候选信号的志愿者开放。好奇的志愿者就能轻松知道“他们的”信号究竟是什么——可能只是个测试信号,或是电波干扰;但也有可能,只是有可能,是真家伙!

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参与人数 2基本分 +10 维基拼图 +30 收起 理由
昂宿星团人 + 30 我来啦!
cuihao + 10 感谢翻译,正式发分什么的交给喵星人了。.

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