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Jobs in Industry# Environmental - 环境科学与工程

G*G2010-01-26 08:01

1 楼

I just don't feel like there's a risk of having a complication from swine
flu is high enough to proceed to taking that, but I would be open in the
future once there was more data available.
Could you help me correct the sentence above?

b*s2010-01-26 08:01

2 楼

而且搞得特神秘。如果问个白话文翻译，都没人理我。

t*k2010-01-26 08:01

3 楼

66岁

A*O2010-01-26 08:01

4 楼

【以下文字转载自 Programming 讨论区】
发信人: AGOO (AGO), 信区: Programming
标题: 请教从java call matlab的问题
发信站: BBS 未名空间站 (Sat Apr 11 12:00:05 2009)
先把matlab的m文件通过mcc转成lib和ctf文件，然后通过c++写了一个wrapper来调用，
接着用mbuild将它们link成dll文件，最后从java调用。以前我这么干就可以。可是我
昨天修改了一下wrapper的code，重新编译后，运行就会崩溃。原因是在check
mclInitializeApplication的时候返回false。请问应该如何解决这个问题。感觉不是
code的原因，倒是跟编译或者运行环境有关。不过没有找到解决的办法。

s*t2010-01-26 08:01

5 楼

关于时间序列中使用intrumental variable的问题，请教一下各位
举个例子吧，好说一点
如果我用housing price 来预测housing supply，在通常情况下，需要用intrumental
vairbable和2SLS，而不是直接使用price。
假如我对price和supply都取difference，在模型中用他们的changes，而不是levels，
还有identification的问题嘛？还需要使用instrumental variable嘛？
我用wooddrige课本上的方法检测了endogneity，结果显示，没有这个问题，但是我想知
道理论上有没有这个说法。谢谢各位了。

s*12010-01-26 08:01

6 楼

1. Company Name: Kleinfelder- DC
Job Title: Geologist or Environmental Engineer
Location: Littleton, MA
Profession: Environmental Engineering
Job Description:
Description Kleinfelder is an employee-owned science and engineering
consulting firm providing solutions to meet our world's complex
infrastructure and natural resource challenges. Working as a team, our
bright people will deliver the right solutions.
We exist to serve our clients, our people and our communities.
Our success can be directl

f*e2010-01-26 08:01

7 楼

说实话
我没看懂

m*s2010-01-26 08:01

8 楼

原文不是白话文，已经是最通俗的文字。看不懂是因为你很多基本专业术语不明白，你
自己需要好好学习。不明白的东西就说人家封建迷信，你要好好检讨你自己。

c*c2010-01-26 08:01

9 楼

默哀一下。

【在 t**k 的大作中提到】

: 66岁

u*a2010-01-26 08:01

10 楼

Matlab里有java接口，为什么要用c++在中间转呢？

【在 A**O 的大作中提到】

: 【以下文字转载自 Programming 讨论区】
: 发信人: AGOO (AGO), 信区: Programming
: 标题: 请教从java call matlab的问题
: 发信站: BBS 未名空间站 (Sat Apr 11 12:00:05 2009)
: 先把matlab的m文件通过mcc转成lib和ctf文件，然后通过c++写了一个wrapper来调用，
: 接着用mbuild将它们link成dll文件，最后从java调用。以前我这么干就可以。可是我
: 昨天修改了一下wrapper的code，重新编译后，运行就会崩溃。原因是在check
: mclInitializeApplication的时候返回false。请问应该如何解决这个问题。感觉不是
: code的原因，倒是跟编译或者运行环境有关。不过没有找到解决的办法。

x*42010-01-26 08:01

11 楼

the reason why there is an endogeneity issue in your settig is that the
price is determined by both supply and demand. without controlling for
demand, i do not think your identification strategy works. Ideally, you want
to find some exogenous shocks (variation) that only affect housing demand
but not the housing supply, which helps you identify the system... i know,
finding a good IV is really hard... good luck!

intrumental
想知

【在 s*******t 的大作中提到】

: 关于时间序列中使用intrumental variable的问题，请教一下各位
: 举个例子吧，好说一点
: 如果我用housing price 来预测housing supply，在通常情况下，需要用intrumental
: vairbable和2SLS，而不是直接使用price。
: 假如我对price和supply都取difference，在模型中用他们的changes，而不是levels，
: 还有identification的问题嘛？还需要使用instrumental variable嘛？
: 我用wooddrige课本上的方法检测了endogneity，结果显示，没有这个问题，但是我想知
: 道理论上有没有这个说法。谢谢各位了。

m*12010-01-26 08:01

12 楼

LZ好勤快，不过要求的工作经验太高。
悄悄话；头像是你宝贝？

G*G2010-01-26 08:01

13 楼

me too. the 'is' in the second line may be wrong.

【在 f********e 的大作中提到】

: 说实话
: 我没看懂

w*r2010-01-26 08:01

14 楼

欢迎欢迎，
但这样反对太空洞了，
来点实际的？

【在 b**********s 的大作中提到】

: 而且搞得特神秘。如果问个白话文翻译，都没人理我。

s*t2010-01-26 08:01

15 楼

我的问题是，对于price，如果我用的是difference，而不是level的话，还有没有这个
identification的问题？

want

【在 x********4 的大作中提到】

: the reason why there is an endogeneity issue in your settig is that the
: price is determined by both supply and demand. without controlling for
: demand, i do not think your identification strategy works. Ideally, you want
: to find some exogenous shocks (variation) that only affect housing demand
: but not the housing supply, which helps you identify the system... i know,
: finding a good IV is really hard... good luck!
:
: intrumental
: 想知

s*12010-01-26 08:01

16 楼

头像是随意找的，呵呵。

【在 m*******1 的大作中提到】

: LZ好勤快，不过要求的工作经验太高。
: 悄悄话；头像是你宝贝？

x*s2010-01-26 08:01

17 楼

Please include a few sentences before this one to establish context.

【在 G***G 的大作中提到】

: me too. the 'is' in the second line may be wrong.

b*s2010-01-26 08:01

18 楼

版主是要引诱我灌水啊，然后众封建迷信受害者对我群起而攻之。。。

【在 w*******r 的大作中提到】

: 欢迎欢迎，
: 但这样反对太空洞了，
: 来点实际的？

x*42010-01-26 08:01

19 楼

i answered your question in my previous post: "without controlling for
demand, i do not think your identification strategy works"

【在 s*******t 的大作中提到】

: 我的问题是，对于price，如果我用的是difference，而不是level的话，还有没有这个
: identification的问题？
:
: want

a*e2010-01-26 08:01

20 楼

楼主能帮我递一下简历么？

w*y2010-01-26 08:01

21 楼

我英文写作也不是很好，不过，我可以式着改一下。
There is not enough data suggesting that swine flu will increase the risk
of having a complication. However, if there are more data available in the
future to support that the risk of having a complication from swine flu is
high, I am open to procceed it.

【在 G***G 的大作中提到】

: I just don't feel like there's a risk of having a complication from swine
: flu is high enough to proceed to taking that, but I would be open in the
: future once there was more data available.
: Could you help me correct the sentence above?

b*s2010-01-26 08:01

22 楼

你能不能热心点，帮忙解释一下呢？

【在 m******s 的大作中提到】

: 原文不是白话文，已经是最通俗的文字。看不懂是因为你很多基本专业术语不明白，你
: 自己需要好好学习。不明白的东西就说人家封建迷信，你要好好检讨你自己。

t*g2010-01-26 08:01

23 楼

Simplified notations are introduced to show why you fail:
y_t= b * x_t + u_t (1)
Its lag:
y_{t-1}=b * x_{t-1} + u_{t-1}
Take a difference:
y_t-y_{t-1}=b*(x_t-x_{t-1})+(u_t-u_{t-1}) (2)
Endogeneity takes place in (1), i.e. x_t,u_t is correlated; now you consider
(2) and wonder whether endogeneity is gone, i.e. (x_t-x_{t-1}), and (u_t-u_
{t-1}) is uncorrelated? In general, this is not true.
Unless you make this strict assumption, you still suffer endogeneity. Could
you explain a

【在 s*******t 的大作中提到】

c*o2010-01-26 08:01

24 楼

对第一个工作感兴趣，怎么申请啊？

【在 s*******1 的大作中提到】

: 1. Company Name: Kleinfelder- DC
: Job Title: Geologist or Environmental Engineer
: Location: Littleton, MA
: Profession: Environmental Engineering
: Job Description:
: Description Kleinfelder is an employee-owned science and engineering
: consulting firm providing solutions to meet our world's complex
: infrastructure and natural resource challenges. Working as a team, our
: bright people will deliver the right solutions.
: We exist to serve our clients, our people and our communities.

m*s2010-01-26 08:01

25 楼

你我没有缘分

【在 b**********s 的大作中提到】

: 你能不能热心点，帮忙解释一下呢？

s*t2010-01-26 08:01

26 楼

thanks.
Wooldrige suggests a two-step procedure to test the endogeneity of a single
explanatory variable:
step1: estimate the reduced form for Y_2 (suspected to be endogenous) by reg
ressing it on ALL exogenous variables,including intrumental variables and th
ose in the structral equation, and save the residuals
step2: add the residuals to your structural equation and test its significan
ce. If it is sig, we conclude that Y_2 is endogenous.

consider
u_
Could

【在 t****g 的大作中提到】

: Simplified notations are introduced to show why you fail:
: y_t= b * x_t + u_t (1)
: Its lag:
: y_{t-1}=b * x_{t-1} + u_{t-1}
: Take a difference:
: y_t-y_{t-1}=b*(x_t-x_{t-1})+(u_t-u_{t-1}) (2)
: Endogeneity takes place in (1), i.e. x_t,u_t is correlated; now you consider
: (2) and wonder whether endogeneity is gone, i.e. (x_t-x_{t-1}), and (u_t-u_
: {t-1}) is uncorrelated? In general, this is not true.
: Unless you make this strict assumption, you still suffer endogeneity. Could

s*12010-01-26 08:01

27 楼

http://boston-jobs.jobfox.com/engineering/environmental-engineering/geologist-or-environmental-engineer/ed9386c417-dde9-47e7f2-9472b-d54e13e8ff2bf50?source=indeed0

【在 c*******o 的大作中提到】

: 对第一个工作感兴趣，怎么申请啊？

s*t2010-01-26 08:01

28 楼

another question:
if I also use price changes at t-1, t-2, do I also have to use intrumental v
ariables for them, like what I do with the price change at time t?
thanks.

single
reg
th
significan

【在 s*******t 的大作中提到】

: thanks.
: Wooldrige suggests a two-step procedure to test the endogeneity of a single
: explanatory variable:
: step1: estimate the reduced form for Y_2 (suspected to be endogenous) by reg
: ressing it on ALL exogenous variables,including intrumental variables and th
: ose in the structral equation, and save the residuals
: step2: add the residuals to your structural equation and test its significan
: ce. If it is sig, we conclude that Y_2 is endogenous.
:
: consider

c*o2010-01-26 08:01

29 楼

Thanks a lot!

【在 s*******1 的大作中提到】

: http://boston-jobs.jobfox.com/engineering/environmental-engineering/geologist-or-environmental-engineer/ed9386c417-dde9-47e7f2-9472b-d54e13e8ff2bf50?source=indeed0