f**n
发帖数: 155 | 1 Let's say there is an arbitrary shape in a 3D volume. How to fill the shape
using an ellipsoid with much smaller size? Additional constraints are:
1. The 3D shape must be fully covered. Overlap of ellipsoids are allowed.
2. The number of used ellipsoids is minimized.
Any thought?
Thanks! |
|
e***e
发帖数: 3872 | 2 interesting problem.
misfilling criteria? any regularity constraints on the volume?
i guess with a well regularized volume, you could apply some tricks like
spectrum analysis or ellipsoid decomposition.
shape |
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f**n
发帖数: 155 | 3 Your right. One more condition, all the ellipsoids have the same orientation
besides size.
is |
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e***e
发帖数: 3872 | 4 it's still problematic. but you could, for example, think of a solution
using PCA, taking a constructive solid geometry representation of the
shape under processing. the solution is then always a trade-off between
number of ellipsoids and the precision of coverage.
orientation |
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L***n
发帖数: 6727 | 5 那么基类是什么? 看起来前五个都是ellipsoid或者特殊的ellipsoid，最后一个
有点general了，也许用template把维度加进来？ particle设计成另一个类吧 |
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L***n
发帖数: 6727 | 6 如果你把boundary 假定成 ellipsoid或者union of ellipsoids，把
数据，就是三个半轴长放在基类，然后派生类定义方法的具体实现，比如
设计检查particle是否和boundary碰撞等等，在派生类上定义distribution,
etc呢? |
|
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x******i
发帖数: 3022 | 8
I think the following is true:
suppose A and B are both symmetric and positive definite,
with B strictly positive definite, and suppose C= A+B
then if we list A's eigenvalues as
a_1>=a_2>=a_3>= ... >= a_n
and C's eigenvalues as
c_1>=c_2>=c_3>= ... >= c_n
then
c_1 > a_1
c_2 > a_2
c_3 > a_3
...
c_n > a_n
This can be easily proved by recognizing that the ellipsoid
corresponding to x*C*x = 1 lies strictly within the ellipsoid
corresponding to x*A*x = 1.
Suppose the eigenvectors corresponding to a_ |
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s***e
发帖数: 5242 | 9 by Freeman Dyson
12/2010
In 1946 Subrahmanyan Chandrasekhar gave a talk at the University of Chicago
entitled “The Scientist.” 1 He was then 35 years old, less than halfway
through his life and less than a third of the way through his career as a
scientist, but already he wa reflecting deeply on the meaning and purpose of
his work. His talk was one of a series of public lectures organized by
Robert Hutchins, then the chancellor of the university. The list of speakers
is impressive, and included ... 阅读全帖 |
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d****n
发帖数: 10034 | 10 不明白什么叫坐标体系和算法都是保密的。美国的大地测量，ellipsoid, geoid,state
plane system， 怎么投的影，坐标全是公开的，benchmark也全是公开的，并且怕你
在野外找不到,每个benchmark都有详细说明，从哪条路走，怎么拐，benchmark在哪个
角落，全由说明。 |
|
t*********r
发帖数: 2558 | 11 1996
Brake Assist (BAS) is launched as another world first in the S-Class (140
series), CL-Class (C 140) and SL (R 129), with the remaining Mercedes- Benz
model series following in 1997.
1997
The ellipsoid firewall and automatic child seat recognition make their debut
in the new SLK Roadster (R 170).
1998
The 210-series E-Class becomes the first model to be fitted with the newly
developed windowbag. The new S-Class (220 series) is the first model from
Mercedes-Benz to feature an adaptive front p... 阅读全帖 |
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b*******y
发帖数: 1240 | 12 software相关，我现在问题是会一些编程语言，用这些语言也做过不少活，但就是不够
focus，所以也可能成为一种劣势
thanks for all suggestions or help!
============================================================================
==============
SUMMARY OF QUALIFICATIONS
Highly motivated engineering program graduate with a proven academic record
and hands-on experience. Team player, attentive listener, and persuasive co
mmunicator. Strong relationship builder, adept at partnering with staff, and
clients. Detail-oriented with acute software design, d... 阅读全帖 |
|
b*******y
发帖数: 1240 | 13 软件相关的
thanks in advance
==================================================================
SUMMARY OF QUALIFICATIONS
Highly motivated engineering program graduate with a proven academic record
and hands-on experience. Team player, attentive listener, and persuasive co
mmunicator. Strong relationship builder, adept at partnering with staff, and
clients. Detail-oriented with acute software design, debugging and QA test
ing skills. Proficient programming abilities with 3+ years .NET and JAVA sof
... 阅读全帖 |
|
h*******e
发帖数: 1968 | 14 【 以下文字转载自 Science 讨论区 】
发信人: happylife (美丽人生), 信区: Science
标 题: 答辩成功
发信站: BBS 未名空间站 (Mon Aug 29 12:36:40 2005)
就刚才，还挺酷的
几个不同领域的课题一起来，从photonic quasicrystal
到ellipsoids packing 等等。
总共练过两遍，本来想多练习一下，但是没人的时候根本不肯能
集中注意力一页一页讲下去，所以没有多练，就是上去就讲，
看来有人说
10分钟的talk练习8遍，60分钟的练习1-2遍是有道理的。
意外之一，
Phil 安德森突然在答辩开始前出现，我没有请他啊，怎么会这么感兴趣，
弄得我一度认为他是专门来问刁钻问题的，不过最后也没有问什么难的。
早知道他有兴趣，又有时间，就请他做委员了。
意外之二，
我明明关闭了所有msn，qq, 讲到一半，突然一个窗口从右下角出来，上面写着
Dolly虽然年纪大了，还是喜欢靓颖has just signed in
吓的我上下翻了两页都没有关掉那个冬冬，嘴里念念有词：
what's that, 然后按快捷 |
|
c*****1
发帖数: 3240 | 15 不是专业的，贴点图，海平面气压
500hPa等压面位势高度geopotential height
500hPa季节变化，上面的是冬季下面的是夏季
但是气象里面用的是geopotential height，跟海平面高度MSL elvation不一样
而跟当地的地球引力系数有关，地球是椭圆的，极地的引力系数要比赤道大
可以用一个复杂的公式通过ellipsoidal radius把geopotential height转成elevation
期待专业的来算算，呵呵 |
|
b*******t
发帖数: 33714 | 16 我师弟总结傅立叶光学就是几个积分kernal和无数的k-space ellipsoids |
|
y****g
发帖数: 36950 | 17
哈哈哈哈哈哈，你又输了，人类已经意识到保护动物的重要性了，野生孔雀是国家级保
护动物，不可以乱杀。会被大陆公安抓去坐牢的。
另外你不要信口开河孔雀的天敌被人捕杀完了。没有科学依据。还有人因为孔雀毛好看
而养殖孔雀观赏呢，所以人类社会对自然的破坏或者保护并不属于进化论里的天敌范畴。
是你东扯西扯暴露你的无知的，我是在谈论男女有别，男人创造力比女性强。而你跳出
来扯到什么创造力冒险精神让人死的早，还扯什么到什么鸟玩意，我是教育你要多读书
才费心写了这些帖子，你不用谢我了，我这算是对你的人道关怀。
至于蝴蝶我是在告诉你无毒的动物用鲜艳的色彩和图案作为保护色来恐吓敌人的事实。
死的早也是创造力强。死不死和你没关系。哈哈哈
另外，看看人家的论文质疑你的所谓的性择论：
http://www.answersingenesis.org/articles/tj/v15/n2/peacock
Problems with the theory of sexual selection
If future experiments show that there are no preference genes ... 阅读全帖 |
|
t******n
发帖数: 2939 | 18 ☆─────────────────────────────────────☆
purity (purity) 于 (Wed Aug 17 00:41:32 2011, 美东) 提到:
看到一些猪头男一直在网上说女人不如男人，智力创造力不如男人，
说什么几千年历史证明男人才是社会的强者。
女人之所以弱，无非是因为生育和培养下一代花费太多精力，
怀孕生小孩，对女人来说，就像走过一回鬼门关，
照料下一代女人更是付出无数心血。
要是女人的身体结构如男人般强壮，也不用生育照顾孩子，
跟男人一样把时间精力花在事业上，很多男人会哭，
比起脑袋灵敏度，学习能力，很多男人不如女人。
☆─────────────────────────────────────☆
yugong (愚公挖坑) 于 (Wed Aug 17 01:13:48 2011, 美东) 提到:
我觉得你没有弄清楚为什么，你学数理化是为学而学，这样属于专业培训，老师好，人
聪明勤奋，肯定能拿奖。但是容易高分低能。
但是在复杂的社会环境里事业有成需要创造力，也就是要触类旁通，或者为了应用而学
。你觉得自己够聪明，数理化... 阅读全帖 |
|
H********g
发帖数: 43926 | 19 wikipedia上这个图比较清楚：
1. Ocean
2. Reference ellipsoid
3. Local plumb line
4. Continent
5. Geoid
1是海洋水体（其实这个海洋也是假想的，把海水的密度都假设一致），2是理想的椭球
体地球，3是各地的重力铅垂线，也就是重力方向，4是岩石层，5是geoid
可以看到geoid在海洋上是跟海面一回事（假设没有浪），在陆地上是跟海平面等重力
势能的平面。 |
|
|
L***n
发帖数: 6727 | 21 o i c, boundary不是简单的ellipsoid而是一个3d(or 2d?) surface, 如果是检查
粒子接触面积的话，在子类实现方法是不是更自然一点?基类提供一个纯虚函数
行吗，基类自己计算几何的信息没必要吧
需要
颗粒
处理 |
|
s*******n
发帖数: 1474 | 22 check the book "Ellipsoidal Figures of Equilibrium" by Chandrasekhar |
|
h***r
发帖数: 726 | 23 【 以下文字转载自 Mathematics 讨论区 】
发信人: haier (no nickname), 信区: Mathematics
标 题: karmarkar's paper
发信站: BBS 未名空间站 (Wed Mar 3 17:00:58 2010, 美东)
after the ellipsoid paper, Karmarkar developed the interior point method for
LP.
Does anyone understand why the canonical form, on the first page, is the
following? (WHY Z, not R?)
min x' x
s.t. Ax = 0
\sum xi = 1
x >= 0
x \in R^n, c \in Z^n, A \in Z^(mn)
x' means x transpose
R^n means R to the nth
So, Why c, A in Z, not R???
Thanks! |
|
p********t
发帖数: 1219 | 24 It is a very complicated problem and I don't think there is any easier
method to calculate the ellipsoid distance. |
|
p********t
发帖数: 1219 | 25 It is a very complicated problem and I don't think there is any easier
method to calculate the ellipsoid distance. |
|
a*********n
发帖数: 1331 | 26 census data作了projection (projected coordinate system)之后，这是metadata的
信息，有问题吗？我是project to projected coordinate system，可是为什么"
extent" 或"bounding coordinates"却是geographic coordinate system? 而且我
create centroids也还是经度纬度的数。可是我需要projected coordinate system
Horizontal coordinate system
Projected coordinate system name: NAD_1983_StatePlane_New_Jersey_FIPS_2900_
Feet
Geographic coordinate system name: GCS_North_American_1983
Details
Map Projection Name: Transverse Mercator
Scale Factor at Central Meridian... 阅读全帖 |
|
h***r
发帖数: 726 | 27 after the ellipsoid paper, Karmarkar developed the interior point method for
LP.
Does anyone understand why the canonical form, on the first page, is the
following? (WHY Z, not R?)
min x' x
s.t. Ax = 0
\sum xi = 1
x >= 0
x \in R^n, c \in Z^n, A \in Z^(mn)
x' means x transpose
R^n means R to the nth
So, Why c, A in Z, not R???
Thanks! |
|
k***s
发帖数: 370 | 28 Journal of the Physical Society of Japan:
The Effect of the Brownian Motion on the Viscosity of Solutions of
Macromolecules, I. Ellipsoid of Revolution
J. Phys. Soc. Jpn. 6 (1951) pp. 297-302
URL: http://jpsj.ipap.jp/link?JPSJ/6/297/
DOI: 10.1143/JPSJ.6.297
Journal of the Physical Society of Japan: Energy Dissipation and Entropy
Production in Irreversible Processes of Dilute Systems
URL: http://jpsj.ipap.jp/link?JPSJ/7/554/
DOI: 10.1143/JPSJ.7.554
J. Phys. Soc. Jpn. 7 (1952) pp. 554-559
Thanks a... 阅读全帖 |
|
d******l
发帖数: 43 | 29 On the Neumann function and the method of images in spherical and
ellipsoidal geometry
Source: MATHEMATICAL METHODS IN THE APPLIED SCIENCES Volume: 35 Issue: 4
Pages: 482-496 DOI: 10.1002/mma.1595 Published: MAR 15 2012
Please send to dukebaal at yahoo.com
包子酬谢。 |
|
h*******e
发帖数: 1968 | 30 就刚才，还挺酷的
几个不同领域的课题一起来，从photonic quasicrystal
到ellipsoids packing 等等。
总共练过两遍，本来想多练习一下，但是没人的时候根本不肯能
集中注意力一页一页讲下去，所以没有多练，就是上去就讲，
看来有人说
10分钟的talk练习8遍，60分钟的练习1-2遍是有道理的。
意外之一，
Phil 安德森突然在答辩开始前出现，我没有请他啊，怎么会这么感兴趣，
弄得我一度认为他是专门来问刁钻问题的，不过最后也没有问什么难的。
早知道他有兴趣，又有时间，就请他做委员了。
意外之二，
我明明关闭了所有msn，qq, 讲到一半，突然一个窗口从右下角出来，上面写着
Dolly虽然年纪大了，还是喜欢靓颖has just signed in
吓的我上下翻了两页都没有关掉那个冬冬，嘴里念念有词：
what's that, 然后按快捷健关了无线网卡。
中国同学当然笑爆了，教授都不懂中文，但是也觉得好笑，
我脑子里面嗡嗡的，在完全没有意识的情况下讲了两页slides,
可惜没有录下来，看不到自己讲得什么。
还好很快恢复了。
出来之后，我的另外一个导师说，他 |
|
p*********e
发帖数: 32207 | 31 ☆─────────────────────────────────────☆
tyning (俗人*把糖水进行到底) 于 (Tue Jun 17 16:32:20 2008) 提到:
能用么? 和100多的比如apexcone的有多大区别/
☆─────────────────────────────────────☆
mianhuatang1 (红棉花糖) 于 (Tue Jun 17 16:39:02 2008) 提到:
ebay kit == trash. there are some reputable manufactures like apexcone, ddm
, depo, zkw, ellipsoid etc. i am using depo housing + apexcone projector +
apexcone h1 3000k 55w light. the only complain is the depo plastic is easy
to break. and IMHO zkw housing + apexcone electr |
|
f**n
发帖数: 155 | 32 It doesn't need to be a tight filling. That is to say the outside of the 3D
shape may also be covered, but the fewer the better.
How to apply spectrum analysis to this problem? |
|
e***e
发帖数: 3872 | 33 but still one formalization of the error and the regularity constrains is
necessary, i think.
3D |
|
