m******r
发帖数: 1033 | 1 问题看似极其简单， 是从?eval抄录而来，略作修改。
ev <- function() {
a <- expression(x+y)
list(eval = eval(a ) )
}
tst.ev <- function(a = 7) { x <- pi; y <- 1; ev() }
tst.ev() #-> aa : 7, eval : 4.14
上面这个运行不通，如果加上第二个参数，parent.frame() 就可以了。
按照eval的定义：
Usage
eval(expr, envir = parent.frame(),
enclos = if(is.list(envir) || is.pairlist(envir))
parent.frame() else baseenv())
我不理解的地方是：如果我只指定一个参数，按照eval定义， R应该会默认如下：
eval(a, envir=parent.frame(), enclos = parent.frame())
因为我没有指定envi... 阅读全帖 |
|
k***t
发帖数: 4 | 2 【 以下文字转载自 Postdoc 讨论区 】
发信人: kaust (kaust_faculty), 信区: Postdoc
标 题: Postdocs available in Envir. Nanotech.
关键字: 'Postdocs KAUST Environment Nanot'
发信站: BBS 未名空间站 (Fri Jul 31 00:00:52 2009, 美东)
Two Post-Doctoral Research Associate Positions Are Available in
Environmental Nanotechnology
King Abdullah University of Science and Technology (KAUST) http://www.kaust.edu.sa is an international, graduate-level research university supported by a multi-billion dollar endowment. With sufficient research |
|
t********s
发帖数: 43 | 3 【 以下文字转载自 Overseas 讨论区 】
发信人: tmacmitbbs (tmac), 信区: Overseas
标 题: opening RA position in civil and envir. engr
发信站: BBS 未名空间站 (Wed Mar 28 09:54:56 2007)
There is an opening RA position in water resource of civil and enviromental
engr, immediately needed. If anybody with background of fluid mechanics or
hydraulics or environment or oceanography or any numerical modeling work is
interested in this position, please contact me by email ASAP. Offer will be
issued very fast. |
|
k***t
发帖数: 4 | 4 【 以下文字转载自 Postdoc 讨论区 】
发信人: kaust (kaust_faculty), 信区: Postdoc
标 题: Postdoc positions available in Envir. Nanotech.
关键字: 'Postdoc Environmental Nanotechno'
发信站: BBS 未名空间站 (Fri Jul 31 00:00:52 2009, 美东)
Two Post-Doctoral Research Associate Positions Are Available in
Environmental Nanotechnology
King Abdullah University of Science and Technology (KAUST) http://www.kaust.edu.sa is an international, graduate-level research university supported by a multi-billion dollar endowment. With sufficient |
|
t****e
发帖数: 329 | 5 【 以下文字转载自 NanoST 讨论区 】
发信人: kaust (kaust_faculty), 信区: NanoST
标 题: Postdoc positions available in Envir. Nanotech. (转载)
发信站: BBS 未名空间站 (Fri Jul 31 00:08:48 2009, 美东)
发信人: kaust (kaust_faculty), 信区: Postdoc
标 题: Postdoc positions available in Envir. Nanotech.
关键字: 'Postdoc Environmental Nanotechno'
发信站: BBS 未名空间站 (Fri Jul 31 00:00:52 2009, 美东)
Two Post-Doctoral Research Associate Positions Are Available in
Environmental Nanotechnology
King Abdullah University of Science and Technology (KAUST) ( |
|
d********p
发帖数: 31 | 6 对的。好像pos和envir是redundant arguments。
x=function() {assign('c',1); print(c)}; x()
get('c') # error
x=function() {assign('c',1, envir=.GlobalEnv); print(c)}; x()
get('c') |
|
G*******n
发帖数: 6889 | 7 无数红黄色。。。
R 071920Z MAY 12
FM COMNAVSURFPAC SAN DIEGO CA
TO USS FREEDOM
INFO COMPACFLT PEARL HARBOR HI
COMNAVSURFPAC SAN DIEGO CA
PRESINSURV VIRGINIA BEACH VA
COMLCSRON SAN DIEGO CA
COMLCSRON ONE
BT
UNCLAS
MSGID/GENADMIN/COMNAVSURFPAC SAN DIEGO CA/0805/MAY//
SUBJ/TYCOM MATERIAL INSPECTION REPORT FOR USS FREEDOM (LCS 1)//
REF/A/MSGID:DOC/INSURV/28FEB2008/4370.1//
REF/B/MSGID:DOC/INSURV/06JUN2008/4730.3//
REF/C/MSGID:DOC/COMUSFLTFORCOM/11M... 阅读全帖 |
|
p*********y
发帖数: 1617 | 8 dont worry about God or some super spirit. They cant stand the bad air
envirement and already leave us alone.
The left of us just breathing awfully until one day our later generations
cannot breath at all. It should be lucky that they could find a new planet
to live! |
|
l*********l
发帖数: 1157 | 9 昨天修的车, 收了$820. 今天大概查了下零件和人工费用, 重新打电话给修车行的老板
, 答应给退些钱. 实在不知道实际该收多少, 有知道的TX给个明细, 包子重谢!!
车: dodge 2001 caravan sport v6 3.3L
修的: fuel injector wiring harness
明细: plen gasket: $14.07
fuel injector wiring harness: $294.87
diagnostic time: $180
remove and replace the fuel injector harness (includes R&I upper
intake
manifold) $270
subtotal: parts: $308.94
labor: $450
supplies: $19.99
tax: $30.35
envir( 不知是啥): $8.5
total: $817.78 |
|
W***n
发帖数: 11530 | 10 depends on driving envir too |
|
W***n
发帖数: 11530 | 11
Not for for t most popular AF
but actually there r washable AFs in t market (more expansive)
Good for the envir, less junks in t landfills. |
|
|
p**o
发帖数: 153 | 13 很不错
一作：1 adv.mater.; 1 JACS ; 1 Energy and envir. sci. (IF 9.4) |
|
m******6
发帖数: 6262 | 14 never saw it before.
i live very close paramus park.
i like the one-story envirment.
of |
|
N********n
发帖数: 543 | 15 照US News 的排名， 去年全NJ第八啊， 不低哦？！
http://www.usnews.com/education/best-high-schools/new-jersey/ra
NJ。com的排名也差不多（按SAT成绩）
County School SAT '08 Score '12 Score Pct. Change Grade
Median Home Value
MONMOUTH High Technology High Scho 2113 416.0 442.0 6.3% B
$413,500
MORRIS Academy For Mathematics, Science And Engineering 2112 438.7
443.1 1.0% A $463,200
BERGEN Bergen County Academies 2083 418.0 437.7 4.7% A
$474,200
MID... 阅读全帖 |
|
L*******r
发帖数: 5448 | 16 以前普遍认为雌激素在鱼体内的聚集会导致雄鱼雌性化，并进而影响鱼的生殖。最近
Envir. Sci. Tech. （是不是环境科学最牛的一个期刊了？）一片文章证实，一类可以
影响雄激素发挥正常功能的化合物，anti-雄激素 (antiandrogen)也会在鱼体内聚集
他们将trout放在废水处理排放的环境中生活10天，然后利用各种色谱分析鱼胆汁成分，
最后得出了上面的结论。
有评论认为这个发现加剧了人们对废水（包括工业废水和生活废水）对鱼群生殖繁衍影响
的担忧，并有部分评论认为这有可能通过食物链影响到人类的荷尔蒙。
具体文章请参阅最近的Evironmental Science and Technology，C&EN News有对此的评论 |
|
e*******e
发帖数: 9616 | 17 喂，这只是几个大故事中间不惊意的小插曲=small episode /drama而已。我高中的初
恋才是惊天地泣鬼神。
这些女孩子都是很有个性很辣椒的那种(奇怪，我怎么就没碰到过甜甜的low profile
邻家女孩？估计是我的问题，因为只要男女之间有问题／arguement,肯定是男的有问题
，哈哈)，有些把我带好，有些把我带向重未想过／做过的人生境界／领域。跟我熟悉
的male envirement 完全不同。
琼瑶那种东西没啥知识含量，没有融入体育和政治斗争的男性智慧在里面，更别提受过
中美俩国教育系统彻底洗礼的审美观和价值观的反复冲突和love-rekindle了。
同样的东西不同background的人写出来完全不同的flavor/depth. |
|
f******a
发帖数: 148 | 18 NCR is considered to be the most "democratic" faction in fallout series.
During the quests, you will see the under handed tactic NCR is using against
vault city, and also the infighting of different political factions in NCR.
As for President Tandi, she stayed on as President almost all her life. And
if I remember right, her dialogue can be a little crazy trying to holding on
to power. (Understandable I think, because it takes a strong willed woman
to build up a strong faction in such a hostil e... 阅读全帖 |
|
c*******u
发帖数: 800 | 19 A home visit is necessary to verify your family can provide good care and
envir
oment for the dog. I will not take your words for granted. Without the visit
, I can not let you adopt the puppy. Please give me your address and I'll se
nd back your deposit.
will |
|
n**j
发帖数: 6 | 20 8. Yang Shen, Professor (Seismology and Marine Geophysics), Graduate School
of Oceanography, University of Rhode Island
B.S. 1984 Nanjing University, China (Tectonics and Geophysics)
http://seismolab.gso.uri.edu/~yang/cv_yshen.html
9. Jin-Rong Zhou, Assistant Professor of Surgery, Harvard Medical School
B.S. in Chemistry, 1984, Nanjing University, Nanjing, China
M.S. in Envir. Sci./Nutrition, 1987, Nanjing University, Nanjing, China
10. Hao Zeng , Associate Professor of Physics, SUNY at Buffalo |
|
c****i
发帖数: 27 | 21 http://www.amacad.org/news/classsec2008.aspx
Xie, Xiaoliang Sunney, Professor of Chemistry, Harvard University
http://bernstein.harvard.edu/pages/AboutProfXie.html
Education
1990
Ph.D. Chemistry, University of California at San Diego with Prof. John D.
Simon
1984
B.S. Chemistry, Peking University, Beijing, P. R. China
Professional Appointments
1999 -
Professor of Chemistry, Harvard University, Department of Chemistry and
Chemical Biology
1992 - 1998
Research Scientist to Chief Scientist, Envir |
|
z****e
发帖数: 54598 | 22 lets take a look what is happening between these 2 companies
from wikipedia
http://en.wikipedia.org/wiki/Java_applet
Google has developed their own Android platform that uses Java features and
concepts yet is NOT compatible with standard libraries. This has been a
violation of conditions under that Sun granted OpenJDK patents to use open
source Java for all [30].
so, who is spoiling java world？
google or oracle?
IF google or any other companies do whatever they want to do
whats gonna happen?
we |
|
z****e
发帖数: 54598 | 23 check this out
http://en.wikipedia.org/wiki/Google_Android
Java support
While Android applications are written in Java, there's no Java Virtual
Machine in the platform and Java byte code is NOT executed. Java classes get
recompiled into Dalvik executable and run on Dalvik virtual machine. Dalvik
is a specialized virtual machine designed specifically for Android and
optimized for battery-powered mobile devices with limited memory and CPU.
Android does not support J2ME, like some other mobile |
|
g*****g
发帖数: 34805 | 24 Mobile platform is tight on resource and optimization is necessary.
This is reasonable. It's not like Google has their own J2SE.
and |
|
m******t
发帖数: 2416 | 25 +1. Even JME isn't compatible with JSE to begin with. |
|
t*********i
发帖数: 217 | 26 请问有没有版上的同学熟悉JBOSS+Oracle 的环境? 我们的这里connection pooling 总
是出现 "IO exception, broken pipe", 或者time out 的错。我找到网上有人说在程
序里加一个validation query, 但是developers说已经加了。
请问有碰到过相同问题的吗？非常感谢。 |
|
m****o
发帖数: 182 | 27 这种问题最好上stackoverflow去问，实在需要答案，可以两天后悬赏答案。 |
|
m******r
发帖数: 1033 | 28 多谢。 我还是喜欢在这里问。 因为比较通俗易懂。 我不是developer, 属于自学成才
的。 |
|
m******r
发帖数: 1033 | 29 再问个问题，就是两个函数，f call g.
这个问题看似简单，但涉及到环境问题，所以我加了一堆print 把环境打出来. 如果g
定义在f里面，就成了所谓closure, 问题就简单了，g要什么变量，自己没有，就找f要
，f没有的，就找global ENV. 所有的环境，都是串起来的。
可现在f和g都定义在global ENV, 问题来了，g如果找不到变量，是从f要呢 还是从
global ENV要呢？ f是g的calling environment, gloval ENV是g的defining
environment, 或者叫enclosing environment.
我看的几本书里面，我理解是： 这种情况下要找g的enclosing environment, 就是g的
defining environment. 也许我理解错了。 可书上也没明确说要找calling。
x <- 500
g <- function(x) {
print(x)
print('[inner]==current_environment==')
print(environment())... 阅读全帖 |
|
m*****n
发帖数: 3575 | 30 R里面不守规矩的地方多了去了
你硬要它守规矩，只能是自己绕着弯受累 |
|
m******r
发帖数: 1033 | 31 多谢回答。 我自学R一年有余， 这是我看的最后一本书的最后一个问题，以后不再琢
磨这些个不着边际的底层的东西了。
也许看书看走了眼， thomas mainlund和renkun的书 最后都反复强调enlosing
environment的重要性， 说这是r的一大特点。 就像closure。 A 造出了 A_1, 【江
湖黑话 A_1是closure, A是它的enclosing environment， 是defining environment】
。 如果在全局环境下调用A_1, A_1先要到A里面找变量， 而不是全局环境 尽管你在全
局环境下调用了A_1.
听起来真像个绕口令。 |
|
m*****n
发帖数: 3575 | 32 最守规矩的是python
它告诉你1+1
你连乘除法都能即想即得
你说的这个是基本的lexical scoping法则
例如global有个x
你的函数里又定义个x
在运算时如果再调用x
肯定得找函数里这个x而不是在外面找
如果找不到才会在从里到外的一层一层的外面找
中国俗话管它叫
“县官不如现管” |
|
s*******c
发帖数: 133 | 33 This university located in SaTe Arob? |
|
t******t
发帖数: 3045 | 34 不得不说不可思议
Sodium Hydride
Peking University, Shenzhen, China 518055
NaH) as an oxidation promoter have long been overlooked. Uncovered here are
some unprecedented reactivities of this classical reagent under very mild
conditions, including alcohol oxidation, tandem allylic alcohol oxidation&#
8722;hydride conjugate reduction, and aldehyde oxidative amidation. These
readily implementable transition-metal-free processes feature exceptional
material accessibility, operational simplicity, and : envir |
|
S***n
发帖数: 102 | 35 Watch your language! You came to this country voluntarily with some
expectations. If the reality is not what
you think it is, you can either do/study something you enjoy or you will
have a brighter future based on your
own backgrounds and strengths/weakness and the market needs here, or you can
go back where you belong
to or are comfortable with. Whining is a loser's aptitude. If you are good,
show others with your talent and
success. The winner is these who know themselves, others and the
envir |
|
a*e
发帖数: 431 | 36 You got me right here. hehe..
I know this is a famous quote from William James in his talk to American
teachers over 100 years ago. However, I didn't understand it as mcuh as I
probably should have.. Or, it will be very helpful if you can narrow down
the tremendous implications of the quote..
Talking about the relations between science and art however, Pavel Semenov
(a Soviet psychologist) made a comment on how humans satisfy their hunger for
knowledge in two ways: 1) They observe their envir |
|
w**w
发帖数: 353 | 37 我建议你可以学一点GIS/RS相关的东西，我在国内和在美国都是学的Civil&Envir. Engr.
国内的时候，因为我对GIS/RS感兴趣，所以学了些皮毛，到美国以后老板让我做这方面的
研究，3年期间，学了几门课，做了一个项目，后来凭着这点经验找着了现在的工作。
虽然工资不高，但这一行只要有2－3年的工作经验，拿个6－7万是有可能的。其实GIS/RS
和Civil&Envi. Engr. 结合得还是很紧的，拿FIS study来说，一般每个项目里有大概
30％是给GIS mapping的 |
|
g*k
发帖数: 92 | 38 赞!!! 我给你转到 jobhunting去。 |
|
l********u
发帖数: 823 | 39 原先以为一样呢，这次办H1B，好奇查一下，才发现envir engr 的prevailing wage比
civil engr 多。至少level II的，一年要多4000多刀呢。 |
|
m*l
发帖数: 507 | 40 ☆─────────────────────────────────────☆
littleokdu (wood+earth+one+knife) 于 (Fri Mar 28 21:05:05 2008) 提到:
原先以为一样呢，这次办H1B，好奇查一下，才发现envir engr 的prevailing wage比
civil engr 多。至少level II的，一年要多4000多刀呢。
☆─────────────────────────────────────☆
PANDACOOK (厨师充文人) 于 (Sat Mar 29 20:21:21 2008) 提到:
帮你顶！
比
☆─────────────────────────────────────☆
raymix (民科) 于 (Sat Mar 29 20:27:22 2008) 提到:
同顶
☆─────────────────────────────────────☆
oldfairy (oldfairy) 于 (Sun Mar 30 01:06:26 2008) 提到:
ho |
|
l********u
发帖数: 823 | 41 crop science or natural resource and envir science. |
|
f******f
发帖数: 509 | 42 http://www.envir.gov.cn/eia/erm/1.html，在国内不是有分公司么？/a>
要看什么职位和经验的，外企一般职位5000到1万五，工程师职位（应该在1万到3万之
间），项目经理的话2万到3万吧，跟项目挂钩高级商务经理的薪水高一等。仅供参考。
顺便问一下，我环境本科国内上的，到这边如果读硕士，女的哪个方向的好找工作？申请的program英文是什么，一定要GRE?GMAT 可以代替么？如果不好找工作，我就改读别的了。 |
|
G*O
发帖数: 687 | 43 老美觉得civil和envir还不错吧，咱们看IT太眼红了。 |
|
|
|
|
d********p
发帖数: 31 | 47 哪位给启蒙一下，在这个assign里， pos = -1是什么意思？pos可能的值是什么？比如
pos = 1， 2 又是什么意思？
assign(x, value, pos = -1, envir = as.environment(pos), inherits = FALSE,
immediate = TRUE) |
|
l***y
发帖数: 184 | 48 用R的时候，fit 一个model，然后去求test error， 出现了一个错误提示，看不懂，
也没有google出来，是这样的：
一下是PCA的后半部分，前半部分太长了，就不贴了，
x.score <- x.train.center %*% x.svd$v
n.score<-nrow(x.score)
y=y.train
library(boot)
set.seed(1)
nfolds<-5
folds<-split(sample(n.score),rep(1:nfolds,length=n.score))
train <- data.frame(y=y.train,x.score)
ols.model<-glm(y~.,data=train)
cost <- function(y, y.hat) mean((y.hat>.5)!=y)
test.error.ols <- rep(NA, 256)
for(i in 1:256){
pc.pred <- predict(ols.model,x.test,n.score=i)
test.error.ols[i]... 阅读全帖 |
|
n*****3
发帖数: 1584 | 49 what is the size of the datasets and what tools/envirment you use for it?
N个小 时 is a lot for just wrapper.. |
|
