s**e
发帖数: 1834 | 1 I am a little confused about the difference between these 2 math symbols
"$\sim$" and "$\approx$".
To give an example, let f1(x) = x, and f2(x)=x + x^2, f3(x)=2x.
And we consider x-->0 only.
I think both expression "f1(x) \sim f2(x)" and "f1(x) \approx f2(x)" are
correct. But what about f1(x) vs f3(x)? Should we use "f1(x) \sim f3(x)" or
"f1(x) \approx f3(x)"? |
|
s**e
发帖数: 1834 | 2 Thanks for the reply. Since f1(x) and f3(x) "has the same order", then is
there a symbol that can be use btw "f1(x) vs f3(x)"?
Say, we can write "2x \sim O(x)".
$
f2( |
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B****n
发帖数: 11290 | 3 在大學的時候 那時候數學系多數人都不知道有軟體可以做symbolic integration這種
東西
曾經有一個很困難的不定積分 難倒了許多學生 包括不少研究生 我同學拿maple幾十秒
鐘打了一行指令就算出來了 那時還是驚為天人的 就像十幾年前第一次看人用google搜
尋的感覺一樣 |
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t****c
发帖数: 366 | 4 Major USA ticker symbols?
Thanks |
|
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w*******y
发帖数: 60932 | 6 Amazon:
http://www.amazon.com/Batman-Symbol-Vinyl-Decal-Sticker/dp/B002
Product Features:
Size: 3.8"t X 6"w Color: Shiny Chrome
Precision die cut from Premium Automotive Outdoor Graphics Vinyl.
No background, just the design itself is the decal.
Comes ready to install with easy to follow instructions.
Will last 5-7 year even in extreme conditions.
Regular price $5.99
|
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T*********s
发帖数: 17839 | 7 i did not find any symbol for 2 year too |
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y*****l
发帖数: 5997 | 8 【 以下文字转载自 Stock 讨论区 】
发信人: Banlangen (板蓝根), 信区: Stock
标 题: 股神杯标普五百ticker symbol列表
发信站: BBS 未名空间站 (Fri Jun 8 16:31:50 2012, 美东)
Here you are: (most update 05/25/2012)
MMM
ACE
ABT
ANF
ACN
ADBE
AMD
AES
AET
AFL
A
GAS
APD
ARG
AKAM
AA
ALXN
ATI
AGN
ALL
ANR
ALTR
MO
AMZN
AEE
AEP
AXP
AIG
AMT
AMP
ABC
AMGN
APH
APC
ADI
AON
APA
AIV
APOL
AAPL
AMAT
ADM
AIZ
T
ADSK
ADP
AN
AZO
AVB
AVY
AVP
BHI
BLL
BAC
BK
BCR
BAX
BBT
BEAM
BDX
BBBY
BMS
BRK.B
BBY
BIG
BIIB
BLK
HRB
BMC
BA
BWA
BXP
BSX
BMY
BRCM
BFB
CHRW
CA
CVC
COG
CAM
C... 阅读全帖 |
|
d**********o
发帖数: 1321 | 9 hw3 & hw3b 最终结果
贴一个自己 hw3b 的 match 结果让小伙伴们感受一下我们作业需要的结果是什么样子
的。
如果是同专业的小伙伴，最后拷贝到编辑器中仔细看一下，这个网页因为宽度有限，让
并排两列的比较呈现出来的很变形。
=================================================
Output of Building User Code
Explode the tar
c-.l
c-.y
makefile
scanType.h
symtab.h
symtab.c
20131116163236-(me~~)-CS445-F13-A3B.tar: POSIX tar archive (GNU)
Tests: directory
c-.l: lex description text
c-.y: lex description text
... 阅读全帖 |
|
d**********o
发帖数: 1321 | 10 hw3b deadline前版本
这里我也先公开承认一下自己早前犯过的错误，在这个楼的第 14 页、第 265 楼，我
有贴出自己的hw3b，但现在我必须向亲爱的读者一一您公开道歉。因为当时因为着急，
我没能找到hw3b deadline前的版本，就把这次作业后来的最终版本（也就是那个楼贴
出来的，只剩下ReturnK、CompoundK两条小尾巴的版本，那个版本被我改动了时间戳我
现在已经把它改回来了。相比于急于求成绩，我更希望自己作一个诚实的人，希望大家
能原谅）给贴出来了。因为我们作业deadline之后也还都是可以接着交的，所以任何作
业，老师都是可以根据后来的版本，追终到这个学生的最后进展的，这个最新进展老师
到底给不给分、就要看老师如何下决定了。
deadline前的版本，被我附在下面了。
当然，把自己的这个版本更新后，我愿为这个楼（这一次出来写的所有）属于自己的每
个贴子负责，所有写出来的，都是真实发生过的事。
=================================================
Output of Building User Code
Ex... 阅读全帖 |
|
d**********o
发帖数: 1321 | 11 hw3 & hw3b 最终结果
贴一个自己 hw3b 的 match 结果让小伙伴们感受一下我们作业需要的结果是什么样子
的。
如果是同专业的小伙伴，最后拷贝到编辑器中仔细看一下，这个网页因为宽度有限，让
并排两列的比较呈现出来的很变形。
=================================================
Output of Building User Code
Explode the tar
c-.l
c-.y
makefile
scanType.h
symtab.h
symtab.c
20131123233236-(me~~)-CS445-F13-A3B.tar: POSIX tar archive (GNU)
Tests: directory
c-.l: lex description text
c-.y: lex description text
... 阅读全帖 |
|
d**********o
发帖数: 1321 | 12 hw3b deadline前版本
这里我也先公开承认一下自己早前犯过的错误，在这个楼的第 14 页、第 265 楼，我
有贴出自己的hw3b，但现在我必须向亲爱的读者一一您公开道歉。因为当时因为着急，
我没能找到hw3b deadline前的版本，就把这次作业后来的最终版本（也就是那个楼贴
出来的，只剩下ReturnK、CompoundK两条小尾巴的版本，那个版本被我改动了时间戳我
现在已经把它改回来了。相比于急于求成绩，我更希望自己作一个诚实的人，希望大家
能原谅）给贴出来了。因为我们作业deadline之后也还都是可以接着交的，所以任何作
业，老师都是可以根据后来的版本，追终到这个学生的最后进展的，这个最新进展老师
到底给不给分、就要看老师如何下决定了。
deadline前的版本，被我附在下面了。
当然，把自己的这个版本更新后，我愿为这个楼（这一次出来写的所有）属于自己的每
个贴子负责，所有写出来的，都是真实发生过的事。
=================================================
Output of Building User Code
Ex... 阅读全帖 |
|
k********n
发帖数: 18523 | 13 ☆─────────────────────────────────────☆
kbrhouston (石油工人-一切MM都是普赛，纸老虎) 于 (Sat Nov 5 22:33:29 2011, 美东) 提到:
1来便于查阅
2来便于老牛清水（怕误删）
3便于顶进十大，壮大声势，繁荣古板
4减少肥猫工作（否则他需要花精力查看大家的所有请求贴）
谢谢大家
☆─────────────────────────────────────☆
MB80528 (肥猫(Contrarian)[食MM而肥]) 于 (Mon Nov 7 23:08:16 2011, 美东) 提到:
要最新预测的，
请在此报名股票符号。
打算提供２０到３０个预测。
由最先报名的股票符号开始。
☆─────────────────────────────────────☆
fockugcd (fockugcd) 于 (Mon Nov 7 23:09:47 2011, 美东) 提到:
胖肥猫，是不是永久免费的：）？？？？？？？？？？？？？？？
☆────────────────────... 阅读全帖 |
|
f**d
发帖数: 768 | 14 这是一本计算神经科学的优秀著作，全文拷贝这里（图和公式缺），有兴趣的同学可以
阅读
如需要，我可以分享PDF文件（－－仅供个人学习，无商业用途）
From Computer to Brain
William W. Lytton
From Computer to Brain
Foundations of Computational Neuroscience
Springer
William W. Lytton, M.D.
Associate Professor, State University of New York, Downstato, Brooklyn, NY
Visiting Associate Professor, University of Wisconsin, Madison
Visiting Associate Professor, Polytechnic University, Brooklyn, NY
Staff Neurologist., Kings County Hospital, Brooklyn, NY
In From Computer to Brain: ... 阅读全帖 |
|
c**t
发帖数: 9197 | 15 #define DECISION_BUY 1
#define DECISION_SELL 0
#define DECISION_UNKNOWN -1
//---- Ãëîáàëüíûå ïåðå
ìåííûå
extern bool ExitMarket = false;
extern bool ShowSuitablePeriod = false;
extern bool ShowMarketInfo = false;
extern bool ShowAccountStatus = false;
extern bool ShowStat = false;
extern bool ShowDecision = false;
extern bool ShowDirection = false;
extern bool BlockSell = false;
extern bool BlockBuy = false;
extern bool ShowLots = ... 阅读全帖 |
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d**********o
发帖数: 1321 | 16 最终版本的compiler测试结果
=================================================
Output of Building User Code
Explode the tar
c-.l
c-.y
scanType.h
makefile
symtab.h
symtab.cpp
emitCode.h
emitCode.cpp
20131214164956-huang-CS445-F13-A5.tar: POSIX tar archive (GNU)
Tests: directory
c-.l: lex description text
c-.y: lex description text
emitCode.cpp: ASCII C++ program text
emitCode.h: ... 阅读全帖 |
|
d**********o
发帖数: 1321 | 17 最终版本的compiler测试结果
=================================================
Output of Building User Code
Explode the tar
c-.l
c-.y
scanType.h
makefile
symtab.h
symtab.cpp
emitCode.h
emitCode.cpp
20131214164956-huang-CS445-F13-A5.tar: POSIX tar archive (GNU)
Tests: directory
c-.l: lex description text
c-.y: lex description text
emitCode.cpp: ASCII C++ program text
emitCode.h: ... 阅读全帖 |
|
m********0
发帖数: 2717 | 18 小青蛙一只，轻拍。
最近比较focus on money management，尤其是position sizing。
这里绝大部分都是跟我一样的beginner，基本上很看重入点，什么时候买最好。我转到
期货和外汇以后在这上面下了挺大的功夫，并没有达到原先预想的效果（包括SVM，
Linear，Non-Linear，Wavelets，HONN, Kalman Filter，这些可能以后会有一定的突
破，但现有的概念和理论，实践起来的效果并不会提高多少，甚至没有提高，所以投入
产出比不佳），加上我一年多几千次浅显的交易经验给我的感觉是，入点远没有想象的
重要。50%的正确率够不够？我感觉远大于盈利的需求。
下面的blog有介绍expectancy的重要性，前两天我也引用了他的Risk Adjusted Profit
的概念，把纯profit 算作profit realized - stop loss level（the risk you took,
in fact,
should be more than stop level as it's dangerous to use stp ... 阅读全帖 |
|
y*****2
发帖数: 412 | 19 T400 基本没装什么乱七八糟的东西，或者太高深的东西
Dump log
Microsoft (R) Windows Debugger Version 6.12.0002.633 X86
Copyright (c) Microsoft Corporation. All rights reserved.
Loading Dump File [C:\Windows\Minidump\010712-13930-01.dmp]
Mini Kernel Dump File: Only registers and stack trace are available
Symbol search path is: *** Invalid ***
****************************************************************************
* Symbol loading may be unreliable without a symbol search path. *
* Use .symfix to have the d... 阅读全帖 |
|
e*n
发帖数: 1511 | 20 【 以下文字转载自 Stock 讨论区 】
发信人: mitbbs2020 (bbc), 信区: Stock
标 题: Re: 【Stragety论坛】Trading with correlations.
发信站: BBS 未名空间站 (Sun Jul 25 19:52:04 2010, 美东)
用option当然可以，但不是必须，
用option可以得到更高的leverage，
但是缺点是散户量小，不容易实现market neutral。
比如1.37的hedge ratio，你要long 137和short 100个才能实现。
13和10就不那么好，而且不容易adjust，看附图就知道不怎么neutral的情况。
说stock不便于对冲，这点我不懂你什么意思。
这本身就是market neutral的strategy。
我测试过DISCA和AXP（paper account)，追踪了至少2个月，涨跌幅从来没超过3%的，
但是这反过来说明这不是一对好的pair。
别的pair，没有任何leverage，一年可以做到100%以上的也有，如果我实际做stock到
这个%，
已经很满意了... 阅读全帖 |
|
y*****l
发帖数: 5997 | 21 ☆─────────────────────────────────────☆
tanmaomao (坛猫猫) 于 (Tue Nov 16 18:13:00 2010, 美东) 提到:
RT
☆─────────────────────────────────────☆
tanmaomao (坛猫猫) 于 (Tue Nov 16 18:24:25 2010, 美东) 提到:
发信人: tanmaomao (坛猫猫), 信区: Stock
标 题: Re: 铀价格走势图 (转载)
发信站: BBS 未名空间站 (Tue Nov 16 18:23:29 2010, 美东)
Ux U3O8 Price indicator is the longest-running weekly uranium price series,
used by the industry in sales contracts
☆─────────────────────────────────────☆
tanmaomao (坛猫猫) 于 (Wed Nov 17 09:34:37 20... 阅读全帖 |
|
|
t******g
发帖数: 462 | 23 Rank by AUM
http://www.bloomberg.com/markets/etfs/
Consumer Discretionary
NAME SYMBOL PRICE CHANGE %CHANGE TIME
RETAIL HOLDRS TR RTH:US 109.39 -0.50 -0.46% 15:24
SPDR-CONS DISCRE XLY:US 38.08 -0.38 -0.99% 15:24
SPDR S&P RETAIL XRT:US 51.21 -0.43 -0.83% 15:24
ISHARES-DJ CN SR IYC:US 69.55 -0.44 -0.63% 15:24
VANGUARD CN DI E VCR:US 60.62 -0.69 -1.13% 15:24
Consumer Staples
NAME SYMBOL PRICE CHANGE %CHANGE TIME
SPDR-CONS STAPLE XLP:US 31.56 -0.10 -0.30% 15:24
VANGUARD CN ST E VDC:US 8... 阅读全帖 |
|
a*****e
发帖数: 1717 | 24 Here's python one I used before,
drawbacks:
1. data pacing violation, limit on size of each quote, interval etc.
2. futures symbols are less standardized
3. IB data sucks, but ok for median to long term backtest
4. the ibpy is out-dated, you have to update yourself to get new
features.
#! /usr/bin/env python
# -*- coding: utf-8 -*-
from ib.ext.Contract import Contract
from ib.opt import ibConnection, message
from time import sleep
from datetime import date
import pyodbc, os, sys
# print all mess... 阅读全帖 |
|
l**b
发帖数: 457 | 25 来自主题: JobHunting版 - A家面试题 我当时和你一样，也讨论了100！的方法，说不行，太慢了。还是从string那里入手比
较好。
这个是我当时写的。DP那个方法刚刚写的，实在是很弱，所以如果错了，请轻拍。其他
的基本应该和面试的时候一样。反正写完他就让我把原来for loop是用string的length
做end point的，改成了用symbol最长的length。然后就说没问题了。
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
import java.util.Set;
public class SymbolWord {
// Here is the max length of any symbol
public static final int MAX_SYMBOL_LENGTH = 2;
public String findLongestSymbolWord(List dict, Set
s... 阅读全帖 |
|
n****c
发帖数: 512 | 26 Top 10 Hottest ETFs – May 2010
Direxion: Real Estate Bull 3x, Symbol DRN, up 17.79%
ProShares: UltraPro Russell2000, Symbol URTY, up 13.97%
Direxion: Small Cap Bull 3X, Symbol TNA, up 13.72%
iShares: Dow US Home Construction, Symbol ITB, up 12.40%
Direxion: Developed Market 3X, Symbol DPK, up 12.39%
ETFS Physical Palladium Shares, Symbol PALL, up 12.37%
SPDR S&P Homebuilders, Symbol XHB, up 12.27%
ProShares:Ultra Short MSCI Europe, Symbol EPV, up 9.89%
Market Vectors Junior Gold Miners, Symbol G |
|
m****i
发帖数: 1076 | 27 Lesson: 8
Title: Development of Chords from Scale Tones in Thirds
Level: Beginner
Style: Chord theory
Instructor: Dennis O'Neill
10 February 1993
Introduction.
Many chords can be developed by extracting alternate scale tones,
i.e., using tones that are major thirds or minor thirds apart within a
scale. In this series of exercises, you will begin by building
three-note chords from the major and three minor scales relative to C
major and progress to building seven-note (thirteenth) chords. You
wil... 阅读全帖 |
|
G******e
发帖数: 9567 | 28 As with almost all holidays that have their roots in Christianity,
Easter has been secularized and commercialized. The dichotomous nature
of Easter and its symbols, however, is not necessarily a modern
fabrication.
Since its conception as a holy celebration in the second century, Easter
has had its non-religious side. In fact, Easter was originally a pagan
festival.
The ancient Saxons celebrated the return of spring with an uproarious
festival commemorating their goddess of offspring and of spri... 阅读全帖 |
|
x*****d
发帖数: 704 | 29
不知道你的依据是什么，MGI规定了老鼠的蛋白名要大写：
1.5.2 Protein symbols
Protein designations follow the same rules as gene symbols, with the
following two distinctions:
Protein symbols use all uppercase letters.
Protein symbols are not italicized.
http://www.informatics.jax.org/mgihome/nomen/gene.shtml#ps
另外举个期刊的例子，老鼠的蛋白名和人的一样要大写
Capitalization of gene and protein symbols should be styled according to
species. For example,
Humans and non-human primates:
Full name: peroxisome proliferator–activated rec... 阅读全帖 |
|
s**********8
发帖数: 25265 | 30 http://en.wikipedia.org/wiki/Electronic_signature
Electronic signature
From Wikipedia, the free encyclopedia
may contain original research. Please improve it by verifying the claims
made and adding references. Statements consisting only of original research
may be removed. More details may be available on the talk page. (August 2008
)
The examples and perspective in this article may not represent a worldwide
view of the subject. Please improve this article and discuss the issue on
the talk page.... 阅读全帖 |
|
发帖数: 1 | 31 传统经学的本体论问题
毫无疑义，《周易》经传中最有研究意义的是《易传》，它是《周易》成为哲学著作的
物质基础。更是我们研究本体论问题的切入点。
西方哲学中的本体论(Ontology)问题在中国古代传统经学中有无具体的表现，这或许本
不该是研究《易传·系辞》的一种方式。因为在中西哲学之间进行这种基本概念之间的
比照(Comparison-Communication)，是需要在一个比较严密的工具理性进行制约和诠释
基础之后才能开始操作的。但是，完成这一工作目前又是极其困难的。因为中西哲学所
使用的理性表述形式(Rationale Form)并不是建筑在同一个规范化的世界(
Weltorientierung)当中。而且，作为中西哲学成立的自然科学基础，特别是在对外在
世界(Weltdasein)的解释上又各有其成立的古代科学哲学体系(Wissenschaftlich
Denkendes)，阴阳、八卦的结构体系对外在世界的理解(Methodisches Erhellen)，已
经隔绝了在中西哲学之间进行这种基本概念的比照(Comparison-Communication)的可能
性。这些基本概... 阅读全帖 |
|
M*****8
发帖数: 17722 | 32
.........................................
*** NOTE: PRICE TARGETS & CALCULATIONS ARE APPROXIMATE ***
(Minimum Cash Unit is $1000. Simply multiply for large sums.)
FORECAST FOR TICKER SYMBOL: XOM AS OF 20111109 (YYYYMMDD)
CLOSING PRICE ON 20111109 was 77.3200
STOCK RATING: MODESTLY BULLISH
Short-Term Price Potential is UP: 0.7641 ( 1.00%)
Short-Term Price Target: 78.0841
At Price Target, profit is 9.8823 on $1000 investment. (+0.99%)
Close out >= half of your long position at about 78.0841... 阅读全帖 |
|
M*****8
发帖数: 17722 | 33
.........................................
*** NOTE: PRICE TARGETS & CALCULATIONS ARE APPROXIMATE ***
(Minimum Cash Unit is $1000. Simply multiply for large sums.)
FORECAST FOR TICKER SYMBOL: XOM AS OF 20111109 (YYYYMMDD)
CLOSING PRICE ON 20111109 was 77.3200
STOCK RATING: MODESTLY BULLISH
Short-Term Price Potential is UP: 0.7641 ( 1.00%)
Short-Term Price Target: 78.0841
At Price Target, profit is 9.8823 on $1000 investment. (+0.99%)
Close out >= half of your long position at about 78.0841... 阅读全帖 |
|
e*n
发帖数: 1511 | 34 【 以下文字转载自 Stock 讨论区 】
发信人: mitbbs2020 (bbc), 信区: Stock
标 题: 【Stragety论坛】Trading with correlations.
发信站: BBS 未名空间站 (Sun Jul 25 16:27:03 2010, 美东)
trader1688上也有人提过pair trading，并有人表示怀疑。
这个idea是80年代摩根斯坦利的人提出来的idea，然后finance行业的人又比较liquid
，跳几次槽，这个idea就逐渐流行起来了。
基本的想法是，high correlated的two stocks，spread比较稳定，假如某个时刻出现
了比较背离average的情况，基本上是可以认为一个overprice，一个underprice，然
后long那个underprice的，short overprice的symbol，以期spread恢复至正常。
这里overprice和underprice都是相对而言，加入两个symbol都涨了，期望的是long那
个涨的比short的那个幅度更大，spread还是可以按照... 阅读全帖 |
|
j***j
发帖数: 9831 | 35 Missing from Presidents' Day: The People They Enslaved
http://www.good.is/posts/missing-from-presidents-day-the-people
Schools across the country are adorned with posters of the 44 U.S.
presidents and the years they served in office. U.S. history textbooks
describe the accomplishments and challenges of the major presidential
administrations—George Washington had the Revolutionary War, Abraham
Lincoln the Civil War, Teddy Roosevelt the Spanish-American War, and so on.
Children's books put student... 阅读全帖 |
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w*********g
发帖数: 30882 | 36
Rev. 12:1-5
Now a great sign appeared in heaven: a woman clothed with the sun, with the
moon under her feet, and on her head a garland of twelve stars. Then being
with child, she cried out in labor and in pain to give birth. And another
sign appeared in heaven: behold, a great, fiery red dragon having seven
heads and ten horns, and seven diadems on his heads. His tail drew a third
of the stars of heaven and threw them to the earth. And the dragon stood
before the woman who was ready to give bir... 阅读全帖 |
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y*******n
发帖数: 10103 | 37 货币的5大属性。
(-) Scarcity: final number of the symbols
(-) Fungibility: all symbols are interchangeable, commodity like. Symbol A
is identical to symbol B, and vice versa.
(-) Divisibility: the symbols are easily divisible, so you can divide them
to smaller and smaller portions
(-) Durability: the symbols can survive the test of time and weahther and
won’t be worn out or disappear
(-) Transferability: the symbols can be easily transferred between owners
比特币这类去中心化数字货币都是最优。 |
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y*******n
发帖数: 10103 | 38 哥给你扫扫盲。货币5大属性,你烂木头烂石头哪样都不占。所以他们不是货币。
(-) Scarcity: final number of the symbols
(-) Fungibility: all symbols are interchangeable, commodity like. Symbol A
is identical to symbol B, and vice versa.
(-) Divisibility: the symbols are easily divisible, so you can divide them
to smaller and smaller portions
(-) Durability: the symbols can survive the test of time and weahther and
won’t be worn out or disappear
(-) Transferability: the symbols can be easily transferred between owners |
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m********0
发帖数: 2717 | 39 JUST FYI, no more comments
SELECT a.Symbol, b.AvgVolume, a.[Date], a.Volume
FROM Stock.dbo.stock_daily a
Join (
SELECT Symbol, AVG(Volume) as AvgVolume
FROM Stock.dbo.stock_daily
WHERE Date >= '20100101'
GROUP BY Symbol
) b
ON a.Symbol = b.Symbol
WHERE 1=1
AND a.Volume > 5*b.AvgVolume
AND a.[Date] >= '20101131'
AND b.AvgVolume > 0
ORDER BY a.Symbol, a.[Date]
Symbol Year_AvgVolume Date Volume Ratio
AERL 74756 12/3/2010 667100 8.923698432
AMAC 9247 12/3/2010 78400 ... 阅读全帖 |
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m********0
发帖数: 2717 | 40 The thing is the it's not a graph for any stock. I just make it with the
following R code,
require(TTR)
ret<-cumsum(rnorm(252,sd=0.036))
ret2<-exp(ret)
p<-50*ret2
ma20<-SMA(p,20)
ema20<-emaTA(p,20)
ema50<-emaTA(p,50)
plot(p, type="l")
lines(ema20, type="l",col='green')
lines(ema50, type="l",col='red')
and I used lognormal distribution for the returns, textbook assumptions
for
a big group of models.
skeptic(as exists everywhere), yes, I borrowed this idea from ET. Please
don
't rush to criticize,... 阅读全帖 |
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M*****8
发帖数: 17722 | 41
...................
抱歉，DNDN, SLF,取不到。
*** NOTE: PRICE TARGETS & CALCULATIONS ARE APPROXIMATE ***
(Minimum Cash Unit is $1000. Simply multiply for large sums.)
FORECAST FOR TICKER SYMBOL: SNE AS OF 20111107 (YYYYMMDD)
CLOSING PRICE ON 20111107 was 17.9400
STOCK RATING: MODESTLY BULLISH
Short-Term Price Potential is UP: 0.2570 ( 1.40%)
Short-Term Price Target: 18.1970
At Price Target, profit is 14.3255 on $1000 investment. (+1.43%)
Close out >= half of your long position at about 18.1970
The... 阅读全帖 |
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M*****8
发帖数: 17722 | 42
...................
抱歉，DNDN, SLF,取不到。
*** NOTE: PRICE TARGETS & CALCULATIONS ARE APPROXIMATE ***
(Minimum Cash Unit is $1000. Simply multiply for large sums.)
FORECAST FOR TICKER SYMBOL: SNE AS OF 20111107 (YYYYMMDD)
CLOSING PRICE ON 20111107 was 17.9400
STOCK RATING: MODESTLY BULLISH
Short-Term Price Potential is UP: 0.2570 ( 1.40%)
Short-Term Price Target: 18.1970
At Price Target, profit is 14.3255 on $1000 investment. (+1.43%)
Close out >= half of your long position at about 18.1970
The... 阅读全帖 |
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V******i
发帖数: 306 | 43 You just talked about a toy problem and messed up the concepts, I do not
think you can understand the detail of V90 modem. The short answer is, with
advanced modulation and coding schemes, the transmitted symbol rate of the
modem is much less than the "symbol rate" they presented to you. For example
if you group 4 symbols together as one transmitted symbol, then your
transmitted symbol rate is only 1/4 of the "symbol rate" you want to support
. Again, knowing that these concepts of "symbol rates |
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s****a
发帖数: 501 | 44 symbol是时域上的unit,subcarrier (tone) 是频域上的一个unit. 一个RE就是 1
symbol x 1 tone. 一个RE上面可以放一个complex symbol, which can be any symbol
after modulation such as 16QAM symbol or 64 QAM symbol etc. Therefore, if
you use 16QAM modulation, one RE can carry 4 bits information.
Subframe和slot的划分是和系统的需求有关, 最容易理解的就是每个subframe(每1毫秒
)的开头都需要pilot symbol做channel estimation.
这些东西多看书就了解了... |
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z*****n
发帖数: 7639 | 45 不管是啥频率的信号，propagation延迟只跟距离有关，
而延迟产生的影响只跟一个symbol的duration有关。
802.11b的symbol rate是11Msps。
我觉得你对symbol的理解有偏差。
a symbol is a signal element, within its duration
it doesn't change form.
对于基带信号，比如unipolar NRZL，一个symbol 就是
信号电平维持在+V 或者0V的时间。对于调制信号，
比如QPSK，一个symbol就是信号相位维持在某个
constellation point的时间。跟载波频率没啥关系，
跟基带信号的symbol rate一致。
4G |
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o**1
发帖数: 6383 | 46 ☆─────────────────────────────────────☆
MarketMaker (BigWave) 于 (Wed Nov 10 16:44:14 2010, 美东) 提到:
I always thought respect is mutual.
《每日电讯报》说，卡梅伦与阁员在人民大会堂时，拒绝中方对他们除下罂粟花的要求。
该报引述随行的一名首相府人员说：“中方人员对我们说佩戴罂粟花是不恰当的，因为
两国曾经发生鸦片战争。我们告诉他们这花对我们有重大意义，我们所有人会继续佩戴
。”
很多英国人习惯在11月份在衣襟佩戴罂粟花，纪念两次大战和其他战争中牺牲的英国军
人和平民。
http://en.wikipedia.org/wiki/First_Opium_War
The first Opium War was the beginning of a long period of weakening the
state and civil revolt in China, and long-term depopulation. In 1842, China'... 阅读全帖 |
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发帖数: 1 | 47 The Liberty Bell
Liberty Bell
Tradition tells of a chime that changed the world on July 8, 1776, with the
Liberty Bell ringing out from the tower of Independence Hall summoning the
citizens of Philadelphia to hear the first public reading of the Declaration
of Independence by Colonel John Nixon.
The Pennsylvania Assembly ordered the Bell in 1751 to commemorate the 50-
year anniversary of William Penn's 1701 Charter of Privileges, Pennsylvania'
s original Constitution. It speaks of the rights and... 阅读全帖 |
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t*******r
发帖数: 22634 | 48 另外这题可以用通常解方程的解法跟娃讲，但不要用具体解方程的方法，
讲述思想即可。
解方程的办法，其实就是 symbol reduce，strategy 是 reduce
number of symbol in an equation。比如可以这么来：
red_circle + green_circle = 11
red_circle - green_circle = 2
reduce ... put two equation together:
但这个教两年级娃可能有困难，俺家现在三年级/开学四年级的娃，能
看懂并且 participate 解类似的 symbol math（比这个复杂些，
是个 symbol math puzzle，要寻找可能的 equation 的排列组合），
但是至少她不喜欢独立去解。。。俺也就不填鸭了。。。
我觉得在概念上，symbol reduction 比 spatial search 更难
理解/comprehend。
当然，解线性方程这种 symbol reduction，容易依葫芦画瓢。。。
上面也可能是导致许多人误认为自然语言数字也是有 place ... 阅读全帖 |
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M*****8
发帖数: 17722 | 49
.............................
多数股票是在被打压的情况。
i.e. Bear Raid
*** NOTE: PRICE TARGETS & CALCULATIONS ARE APPROXIMATE ***
(Minimum Cash Unit is $1000. Simply multiply for large sums.)
FORECAST FOR TICKER SYMBOL: BKS AS OF 20111122 (YYYYMMDD)
CLOSING PRICE ON 20111122 was 17.9000
STOCK RATING: ESSENTIALLY NEUTRAL
Short-Term Price Potential is DOWN: -0.5348 (-3.00%)
Short-Term Price Target: 17.3652
At Price Target, profit is 29.8771 on $1000 investment. (+2.99%)
Close out >= half of your short pos... 阅读全帖 |
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M*****8
发帖数: 17722 | 50
.............................
多数股票是在被打压的情况。
i.e. Bear Raid
*** NOTE: PRICE TARGETS & CALCULATIONS ARE APPROXIMATE ***
(Minimum Cash Unit is $1000. Simply multiply for large sums.)
FORECAST FOR TICKER SYMBOL: BKS AS OF 20111122 (YYYYMMDD)
CLOSING PRICE ON 20111122 was 17.9000
STOCK RATING: ESSENTIALLY NEUTRAL
Short-Term Price Potential is DOWN: -0.5348 (-3.00%)
Short-Term Price Target: 17.3652
At Price Target, profit is 29.8771 on $1000 investment. (+2.99%)
Close out >= half of your short pos... 阅读全帖 |
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