迅雷研究笔记

迅雷平台游戏业务的用户粘性

  1. 平均用户游戏活跃时长为1-6个月

迅雷现金流问题

从2013年到2016年,迅雷营收从1.18亿美元上升到1.56亿美元,与此同时,经营现金流和自由现金流均出现大幅下跌,分别从8千5百万美元和4千2百万美元下降到4千2百万美元和2百万美元。

2017年底,迅雷的账面现金仅为23万美元。正常么

2018年3月随笔

  1. 艰苦创业的阶段,此时创始团队是整个公司的前进动力,创始人是拉车的人

  2. ADR (American Depository Receipts)
    ADR由美国存托银行保管,每一份存托凭证代表了一股、多股或几分之一股在运营主体在美国之外的公司。美国存托凭证的所有者有权索取ADR所代表公司的股票。

  3. ADS (American Depository Share)
    ADS是美国存托股份,是ADR所代表的公司股份。

  4. 在美国上市的外国公司不需要提交季度财务报告

  5. PE/PB/PS

    Price/Earnings
    Price/Book
    Price/Sales
    三种不同的估值方式,需要在考虑行业特征和企业业务特点后酌情选用

  6. Form 20-F Annual Report
    Form F-1 Registration Prospectus

值得注意的是,美国多层次的场外交易市场为退市机制提供了后续通道。美国上市公司从一个市场退市后,除了进入破产程序的公司,大多数公司可以退到场外交易市场证券市场上挂牌。该OTC市场主要由OTCBB(店头报价公告栏市场)和PINK SHEETS(粉红单市场)两部分市场组成。二者一个较大的区别在于挂牌标准不一,退市公司可以根据自己的意愿选择到哪一个市场去挂牌。

2018年2月随笔

  1. 金融交易的本质是Asset Re-allocation
  2. 判断新事物可跟进性的标准是是否有可能从中盈利
  3. 局势决定市场情绪,市场情绪决定价格走势
  4. 技术应用离变现的距离决定是否值得投入

Financial Market Modelling

Stock market is a game market in which asset re-allocation happens everytime. It is interesting that stock market functions both as a place of capital investment and financial arbitrage. Initial share offering (IPO) pumps money into the market. Stock trading is an exchange between corporation and the investors. Stock trading between investors does not affect the balance sheet of the corporation.

"Money inside the market" refers to the overal valuation of the stocks in the market. It is the circulation of currency in the market. The circulation of currency happens together with the circulation of stocks.

There are many historial patterns of the market both in long-term and short-term, paired with economy patterns.

Asset valuation is a subjective, opinion based process substantially affected by human bias. Investor irrelationality is the basis of stock market arbitrage.

The flucation of stock prices is directly caused by trading orders, which is caused by the following two factors (independent of each other, but may function jointly to determine the bid/ask price):
1. The news of the corporation (fundamentals of the company)
2. The bid/ask of other market participant (the movement of other players)

Stock market has two functions, asset valuation and medium of exchange.

Bid-ask Spread

Unmatched ask price (monetary unit in currency in exchange of stock) is always higher than bid price, the difference between ask price and bid price is the bid-ask spread.

Supposedly, the bid-ask matching system will execute a trade when the price of sell order is equal or lower than a buy order. The execution price will be the price of the sell order, as it satisfies the monetary requirement for such trade, meanwhile potentionally saves money for the buyer.

The executation price will always be the ask price.

Special Thoughts

how to deal with situations when team members are not qualified enough to do the job on schedule, is a problem faced by many mangers in technology field. It is not without budget to hire qualified developer, but not enough prospective canadaicates to interview with. The technology industry is experiencing dramatic shortage in skiled manpower.

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在大牛市背景下,做空交易的成功率显著降低,优质科技股的Intrinsic value保证的大跌的低可能性,牛市背景的看多情绪蔓延推高股价。另外,天然的通胀率也保证的股市市值的放大。

智力模型

fluid intelligence and crystallized intelligence

Order Book Matching Algorithm

Price-Time-Priority-Algorithm

Financial Investment

Algorithmic Trading / Automated Trading

Tensorflow Study Note, Part Three

Session

  1. Interactive Session

tf.InteractiveSession() creates a default session that can be used without explictly called in a IPython environment

Example:

tf.InteractiveSession()
a = tf.constant(1)
a.eval()

  1. Regular Session

Regular session needs to be run within a python context or through session object

Example 1:

a = tf.constant(1)
sess = tf.Session()
sess.run(a)

Example 2:

a = tf.constant(1)
with tf.Session():
a.eval()

tf.add_bias

This function is used to add bias to the input tensor (element-wise addition between "bias" vector and the feature vector)

It should be noted that the bias added here is completed different from the normal concept of adding a bias to the hidden unit (summed weight before activation)

tf.Session

The run function of tf.Session provides a interface to execute provided TF operations and evaluate Tensors.

Feature Preprocessing

Continuous features can be feed into the first hidden layer of the neural network directly. Discrete features are recommended to go through an embedding layer.

embed_sequence

This API accepts a [batch_size, doc_length] tensor of type "int32" or "int64"

embedding_lookup

This API is used to loopup an embedding using ID.

Categorial to Embedding Pipeline

Categorial Label ---> Ordinal ID ---> One-hot Embedding ----> Dense Embedding

About Immigration

The Cause of Immigration

The life quality of western countries is far better than that of China in terms of economical, environmental and social conditions. I found myself increasingly believe in western cultures and values and that is the primary driving force of my immigration thoughts. I need to improve my language skill as well as professional experiences to get ready for the oppertunity. Meanwhile, I need to take it very carefully to examine this thought to confirm it is a good fit for me and my family.

I need a carefully planning to merge my immigration effort with the long-term paradigm shift of my family earning, that is, to shift from work-based earning to asset-based earning. (Asset here is something that can generate revenue without extra mental/physical labor)