In Memory of Steve Jobs

He came to this world for only 56 years. But he left us with such a rich legacy. He revolutionized computer industry as it first pioneer, he revolutionized music delivery industry with iPod and iTune. Then he moved on to revolutionize the mobile phone industry. Not to mention his company also pioneered computer animation, and he created a new Tablet market.

For those of us living in Silicon Valley, Steve Jobs seems not far. His house in Palo Alto is not far from where we live, Apple headquarter is just a few streets away, and many Apple employees are our neighbors and friends. Yet Steve Jobs is also a mystery and a legend. He started the company in 1976, when most of engineers at Valley were not yet born. For the next 35 years, he stays at what he loves to do: build great computer products and ship them to people.

Steve Jobs defies convention, but he is also an excellent marketer. Above all, he is a consuming technologist, who loves every part of his product. He is handsome, charming and quick wit. But he did not squander his energy on easy social gain. Instead he poured all his passion in building the real innovative products. He is a creator, an inventor and a pioneer. Deep in his heart, he is pure and passionate about building digital product that can make fundamental impact.

While others retire and go into public limelight, he stays at the peak of his creation, chunking out amazing new products one after another. He has no vanity for public limelight. Instead, he uses them solely for the promotion of his product.

He has devoted his life completely to his work. He is so deeply passionate and devoted to his work that it is unimaginable how he can announce his own retirement. We should have known better, that the candle light was burning out. We did not realize how closely he came to the end of his life. From his retirement (August 25) to his death (October 5), it took only 1 month and 10 days. However, Steve Jobs put on such a brave public face in his retirement announcement, we all believed him as if this is his personal choice. When death comes to deal his hand, even Steve Jobs had no choice.

In the age when people live to their 90s and 100s, 56 seems like middle age. How unfair life is for Steve Jobs, to have to leave this earth so early after such a short stay. But life has endowed him richly with sheer determination, vision, and powerful drive. What life takes away, it has generously given to him beforehand. How can we measure a life by its simple length?

Steven Jobs is an inspiration to all of us. He showed us what is possible, when you dare to try, when you stay firm with your vision, and when you are passionate about what you do.

Life renews itself. New generations will come, and new products will be created day after day. But Steven Jobs stands out with his singular impact. He will be forever remembered as a man who changed our lives.


Eternal Hope

(Review on Man’s Search for Meaning by Viktor E. Frankl)

Frankl’s narrative brings me face to face with Nazi concentration camp: the abhorring degradation of fellow human beings, mass murdering, barbaric treatment of prisoners. Yet, human souls were able to seek comfort in natural beauty in such unbearable existence. Ultimately the book is about triumph, particularly spiritual triumph despite all the suffering one went through. If a person can emerge from such experience: being stripped naked, taken away all possessing, being beaten and starved, doing harsh labor in the bitter winter, facing arbitrary death in every moment, later learned that his parents and wife were all killed in gas chamber, but coming out compassionate, forgiving and becoming a successful doctor and author (publishing 30 books afterwards), how can we not marvel at human resilience?

The eventual survival of Frankl may be due to luck (not boarding the last train), his own social smart (avoiding offending prison guards, befriending the foremen), and kindness from fellow prisoners (extra bread saved, joint escape attempt). But it also crucially depended on his spiritual strength and holding on to the final hope. He called this search of “meaning of suffering”. By assigning meaning to his suffering,  he then would not fall prey to bitter disappointment when liberation did come at an expected date, while a fellow prisoner lost hope and died. In other words, Frankl found a way to maintain eternal hope. It is this hope enables him to stand strong despite any suffering or disappointment.

In the last chapter,  Frankl offered an invaluable explanation on logotherapy. Its methodology is enlightening, much similar to what Anthony Robbins has preached all along in his seminar. Humans need “meaningful goals” to feel happy.

Each of us goes through life with unique experience. No one can repeat that experience for us. Even our suffering is unique. Thus the meaning of our life is put upon us instead of us searching for it. It is how we answer life, in our unique way.

The bare truth of concentration camp, the honesty and the compassion deeply touches me. There is no self pity or hatred. Instead you experience a deep sense of beauty in this writing. All you feel is a much larger understanding for human existence and the ultimate triumph of human spirit.

How can we feel despair when men endured and survived concentration camp? Even if the world problem is daunting, Frankl said, “the world may be in a bad state, but everything will become worse unless each of us does his best”. As horrible as Nazi concentration camp is, Frankl lived to tell the story, to share his experience. All those who died did not die in vain. Ultimately good and justice, and human spirits triumph in this world.

The power of data mining

KDD is the largest and best data minIng conference. This year it is held in the beautiful San Diego. About 1000 people from both Academia and industry attended. The largest presence is Google, Yahoo!, IBM and Microsoft. In addition, EBay, Amazon, Twitter, Facebook are all present. Besides these Internet companies, traditional companies like GE, Siemens, GM, Ford, American Airline, and Jack in the box are also present. Many government agencies are also here: NASA, Department of Defense, just name a few.

What bring all of these diverse organizations together is the power of data mining. In his invited talk, VP marketing of Caesar Entertainment talked about how his company uses patterns discovered from data to support hotel and casino operation. Another invited speaker, talked about helping police to identify crime hotspot in the city. A grocery chain talked about using data mining to manage inventory and product promotion.

Behind all of these commercial applications is solid science, namely mathematics and statistics theories. In addition, it is solid computer science where all algorithms are subject to analysis on computational complexity and evaluated on public datasets.

Twitter researchers are talking about automatically detecting topic with data stream.

The Voyage of Beagle

Imagine 170 years ago, a group of people sailed from England, crossing the Atlantic, arriving at the shore of South America to explore today’s Brazil and Argentina. They met indigenous people and Spanish colonists. Imagine our main hero, who ventured into the inland, lived and interacted with local people, collecting plants and animal specimen to sent back to British museums.

Our hero in this story is Charles Darwin, who demonstrated remarkable bravery and dedication to his work.

I am taken by Darwin’s fluid writing and his keen observation on both nature and human society. I marvel at Darwin’s diligent and meticulous way in doing his research, and his courage of venturing into desert, onto steep mountains and islands. He took the risk of being robbed by bandits but still continued his journey inland. He coudld also be attached by wild animals, yet he moved ahead.

As I listen to the audio book, I was deeply moved by how this naturalist/scientist conducted his survey and research. As he seeked all his evidence, collected new information, and constantly learned about the land, plants, geological change, he created hypotheses. He verified them from all angles and put forth irrefutable theory and evidence. In the voyage, Darwin investigated the formation of coral reefs and created a theory that still holds true today.

The sweeping landscape of the whole globe, from England, through Atlantic Ocean, to South America, the Pacific islands, New Zealand, Australia, Indian Ocean and South Africa are all vividly described in this book. It is indeed a true voyage. It tells the power and wide reach the British empire had at that time. Which country can have such sweeping interests on such global scale? Citizens from Britain went to every corner of the world, and most of those places were newly discovered and uncivilized at that time.  The voyage of beagle is a vivid account of British sea power at that time, and its scientific expedition. It is thus natural that the evolutional theory is developed by a British naturalist, who went with British vessel, circling the whole global, and seeing every part of the world landscape and living creatures.

While the external condition provides fertile ground for a British naturalist to come up with evolution theory, a theory that is so sweeping and profound, it is up to a man who has the capacity to do this job. Another naturalist may pick up bits and pieces, but it is Darwin and his penetrating intellectual vigor and his hard work make such a theory possible.

The curiosity and research scope of Darwin is amazing. He is interested in every plant, every living animal, and the land and sea where they inhabit. He is interested in the geological formation and change. He could explore rocks for hours, or meticulously collected 8 different kinds of insects in one expedition. He observed spiders and their habits, he studied birds and locus. He observed people, tribes, and local governments too. If he devotes his attention to human society, he could have been an excellent social scientist. I was awed by Darwin’s intellectual capacity.

Listen to this book, you will never be disappointed and your life is forever enriched.

iPhone becomes No. 2 smart phone in US

Just read on the web, in 2009, iPhone users finally surpassed windows mobile users. Here is the chart.

Consider the fact that iPhone was launched only a little 2 years ago in June 2007, this achievement is astonishing.

iPhone’s growth is accelerating, while windows mobile is stagnating. Google Android phone has it potential, but still lags far behind iPhone. It will be interesting to see whether iPhone will eventually surpass blackberry. This will happen if AT&T is not the sole carrier for iPhone. Many people want to switch but hesitates because they want to stay with current carriers (Verizon and Sprint).

The secret behind Amazon’s success

What is behind Amazon’s solid growth? What makes it consistently deliver such quality service for the last 16 years? The secret lies with its founder – Jeff Bezos. Like Apple’s Steve Jobs, and Google’s founders Page and Brin, Jeff Bezos is deeply involved with the day-to-day operation at Amazon. He has been with Amazon since its beginning. The consistency of Amazon’s quality service and fast innovation is a direct reflection on Bezos’ personal drive, discipline, business savvy, and vision.

In 1994 Jeff Bezos raised money from his family members to create the first online bookstore. Due to its large book selection including many out-of-print books (a selection much larger than traditional bookstores), Amazon gained popularity among book buyers. Soon Amazon became the largest bookstore, and a success model on how E-commerce can work. After its success as online book seller, Amazon transformed itself into an online retail store. It sells anything from baby diaper to laptop computers. The third move by Amazon was cloud computing. Utilizing its large computing infrastructure, Amazon started to offer cloud computing to small companies who need flexible computing capacities. This pioneered a new era for large-scale on-demand computing. Today, Google, IBM and HP have all entered the market. The fourth prominent innovation Amazon had was its e-reader Kindle. With its wireless sync technology and easiness to purchase, Kindle quickly dominated the e-reader market. Today, Amazon as a company enjoys high growth of about 50% a year. Its online traffic growth is accelerating. Its stock is priced at $146, twice of what it was a year ago.

Bezos is visionary and bold to take risk. He looks far ahead and understands the unique opportunity presented by an initiative. When he launched prime membership on Amazon, where a member pays $80 a year in exchange for free express delivery, it generated a lot of doubt, even within Amazon. But this turned out to be a brilliant move. Prime membership generates large cash up front for Amazon, ensures loyal buyers, and enhances online shopping experience. It’s win-win for both Amazon and its customers.

When Bezos promoted cloud computing, very few people understand the significance of this offer, the technology and business implication. Today, it is at the forefront of the second-wave Internet technology. From Google to IBM, to Cisco, companies with large computing resoures  all vie to be providers for this service.

Bezos instilled a corporate culture of strong customer focus. Everything is about customer experience. All engineering effort supports online shopping experience. Amazon is the first company to show “in stock” status, and the first to promise “ship within 24 hours”. The free return policy makes remote buying easy and riskless.

Most successful companies have customer-cenered policy. But it takes a strong founder to instill it into daily operation of every part of business. Bezos hold meetings with all major product groups regularly, and he asks sharp and insightful questions. In such daily involvement, he has created a coherent goal and consistent performance target. In addition, he instilled his personal drive behind every initiative.

The management of Amazon company is very disciplined and scientific. There are metrics for every stage of engineering. From design, to web testing, to customer satisfaction evalution. The performance of each employee and group is also measured by metrics. Amazon is the first to invent A/B testing for launching new online feaures.

The last secret of Amazon’s success is its people. Amazon attracts a group of highly motivated, self-starting and highly-educated people to its workforce. Like Google, Amazon hires a large amount of Ph.D. computer science graduates, and put them in engineering positions. Once these people are on board, they take initiative in their projects and drive product innovation.  Amazon also hires MBA graduates from top universities around the country.

Amazon’s success is inpiring to all of us. Behind every success, there is a path. With current trend continuing, Amazon will become a much larger and even more formidable company in the next decade. We can learn from its success, and create lasting and successful business.

A glimpse of Steve Jobs

Steve Jobs is back on stage. Just three months after annoucing the new hit iPad. This time he is announcing iPhone OS 4. As I watched the thin and frail-look Steve Job deliver his usual talk, I cannot help feeling sympathy. Afer all, he has had three successful major hits. It seems unnecessary for him to come personally to announce new features on an existing product– iPhone. Such things can be easily handled by his subordinates.  As he held up his frail body on stage, I wonder why he has to do this.

Listening to Steve Jobs’ familiar enthusiastic voice to explain a folder feature, I realize how much he loves every part of this. He is in the trench with the products. He is not just a salesman who promotes Apple product at MacWorld event as we usually see him, he is also deeply involved with all the feature design of these products. In that sense Steve Jobs is more a technologist than a promoter, negotiator or other things he seems to do well.

In the biography book Icon, we see a Steve Jobs flew to Los Angeles, negotiated tough deals with record companies that started a new era of digital music. We learned Steve Jobs forced out Disney CEO Michael Eisner, then sold Disney his company Pixar with high price, and he himself became the largest shareholder of Disney. We also learned the story how Steve Jobs grabbed the power in Apple after he came back in 1991, and forced out former CEO. Steve Jobs presented in the book is a tough negotiator, a fighter who is determined to win. But the book missed the most essential part of Steve Jobs: His love for technology and the products he creates. It is only this love and the resulting products that define the true greatness of Steve Jobs.

On stage, Steve Jobs looked so frail, but he stood upright and gave his best to describe the new OS features in detail. It gave me a glimpse on how Steve Jobs works. This is someone who works very hard. Despite his illness, he poured his energy and passion into every Apple product he helped to create. He gave it all. Other famous people may think about retirement or having cheered tours around, Steve Jobs is still working in the trench of his products. He breathes and lives in what he creates. That is his life and his true love. 

For every product we hold in our hand, be it iPod, iPhone or iPad, we are holding a great man’s passion and love. They are the manifest of his vision, wisdom and willpower. These products are built by thousands of engineers who followed this man’s dream and shared his vision. We are lucky that he is still leading this group of people, and keep giving us so many stellar products year after year.

Today I finally understand the greatness of Steve Jobs. It has nothing to do with glamour, showmanship, or business skill. It is simple devotion. Devoting to your passion, seeing it into fruition, and bringing all resources to make it happen. Such simple truth is inspiring to all of us.

Technology behind Online Advertising

Online advertising becomes instantly popular after Google launched its search-based ads. Google’s success comes from its high traffic where tens of millions of people visit the site daily to search for information. It also comes from Google’s large ad inventory, where millions of advertisers come to bid. Most importantly, search-based ads connects advertiser with the user’s active intent. This leads to high click-through rate, thus offers better results for advertiser and higher revenue for Google.

Given Google’s success, other high-traffic websites also want to enter this market. The question is: How to duplicate Google’s results? A more technical question is: how to conduct ad auction like Google and achieve high revenue from advertising?

Google ads are placed against keyword search. As a user searches on certain keywords, both search results and ads are displayed, with ads on the side. However, there might be hundreds of advertisers bid for the same keywords such as “cars” and “lawyer”. The key question is how to list these ads in reasonable order.

Google lists ads based on two main parameters: 1. Bidding price;  2. Click-through rate. The position of an ad is the combination of these two, such as Bidding price x click-through rate. For example, if an ad has $1 bid price and 0.6 click-through rate, it will be placed higher than an ad with $5 bid price and 0.1 click-through rate. A bidder pays for the bidding price right below his own (a bidder of $5 pays for $4.9 submitted by another bidder). This is called Generalized Second Price Auction[1]. Economists spent a lot of time discussing how this second-price auction is better than the first-price auction by removing incentive of keeping changing bids. In reality, the bidders still constantly change their bids to minimize cost or increase click-through rate. For example, if a bidder observes that position 2 (from bidding $4) generates the same click-through rate as  position 1 (from bidding $5), the bidder would think position 1 and 2 is equivalent and will only bid to stay at position 2, and thus bids $4[2]. This is the reality in online advertisement auction. From Google’s viewpoint, it does not matter how often bidders adjust their price. All that matters is the total revenue from click-through rate and bidding price.

The dominant factor is click-through rate. If no user is interested in clicking the ad, it does not matter how high the bidding price is. How does a website increase click-through rate for the ads it shows? Making the ads relevant is very important. This comes back to the ranking of ads retrieved. Similar to the problem of search result ranking, more than 100 ads may be retrieved from a search of just 2 keywords. Ranking based on relevance is crucial to achieve high click-through rate.

Is ranking of keyword-related ads the same as the ranking of searched documents? It seems the problem of ad ranking is easier because the bidding price determines whether an ad will be placed high or low. Combined with the click-through rate, we have a neat formula for the position of each ad. Here we assume the click-through rate is known. But what if the ad is new and there is no data on its click-through rate? Potentially we can treat this new ad as having the highest possible click-through rate, and multiple it by the bidding price. After 1 or 2 days, the data come in and we can adjust its position to reflect its real click-through rate.

However, ad ranking can be harder than search result (document) when keywords searched by the user do not match any bids, even though those keywords may mean the same things as words bid by the advertisers. Thus Google encourages advertisers to bid for as many keywords as possible to increase the likelihood to be matched. Large E-commerce advertisers bid for close to a million keywords in order not to miss any potential buyer.

Even with the best effort from advertisers, there are still many keywords missed out from bids. This is because casual usage by users may differ from formal words envisioned by advertisers. It is hard to exhaust all possible ways people search or express their need. 

The search company (like Google) is in the unique position of understanding the user’s need. If it needs to return high-quality research results, it needs to find a way to map those search words to existing common words, and be able to retrieve documents accordingly. Thus search company can apply the same technology for improving search results to ad selection. Query expansion is one of such techniques developed.

Another challenging situation is placing ads on pages not related search results. For example, a user may browse certain books and read reviews. Ad display in such case is called Contextual Advertising. There is only context, no search words. One solution is mapping the page content to a set of keywords, the all ads can be displayed accordingly.

Online advertising is a fast growing domain where many high-traffic website wants to create their own ad engine. People not only search for web pages, they also come to E-commerce sites to search for products. They go to social networking site to update their profiles. They go to news website to post comments. There is big potential for generating ads for each of these activities.  

The technology for providing online advertising is closely tied to search relevance technology, but requires additional study on context, and on bidding behavior. At year 2010, this is a fertile ground for cutting-edge computer science research.

[1] Benjamin Edelman, Michael Ostrovsky, and Michael Schwarz: “Internet Advertising and the Generalized Second-Price Auction: Selling Billions of Dollars Worth of Keywords”. American Economic Review 97(1), 2007 pp 242-259

[2] At position 1, our bidder needs to pay the next lower bid say $4.5. Then at position 2, it only needs to pay $3.5 of 3rd highest bidder

The Science of Ranking Search Results

When a user visits a website and types his search keywords, he expects to find relevant information immediately. We take such easy access to information for granted. Behind the scene, there is large amount of work going to retrieving the most relevant pages, and list them in order of relevance. This is called ranking of search results.

There is huge economic incentive for having good ranking. For a web search or social networking company, this means advertising revenue: The user stays on the website, get interested on related ad posting and click on them. For E-commerce company, this means a successful sale. If the user finds the product he is looking for, he will most likely buy it. In addition, for all these companies it is user experience issue. When the user feels happy after finding the information he needs, he is more likely to come back, more likely to explore the website, and more likely to buy something.

Given the importance of ranking of search results, large amount of research and engineering effort have poured into this field. The problem fits nicely with a computer field called Information Retrieval (IR). The field of information retrieval exists since 1978, when the first SIGIR (Special Interest Group on Information Retrieval) conference was held. In this first SIGIR conference[1], all the important concepts were there: Retrieval from database, from file systems, document retrieval, and relevance feedback from the user. But the booming of IR field only started after the Internet search engine (in 1993[2]) and E-commerce (in 1994[3]) came to existence. Big commercial interest and fast growing of online data fuel the development of this field.

The interface between a user and the website is a search box, where the user enters some keywords. Immediately, the system has to respond with some results. How do we present the most relevant information based on a few keywords? The premise is that there will be thousands of pages (documents) matched with simple string matching. After all, there are limited numbers of English words, but there are millions of products and billions of web pages. It is unavoidable that simple keyword match will give us thousands of equally possible results. But there is only limit space to display results on a web page, and the user is not willing to going through page after page to find the result they want (unless they desperately need the answer). Therefore ranking of search results becomes crucial.

Ranking of web pages is almost a solved problem, thanks to Google’s ingenious PageRank[4] algorithm and its continuous modification. It relies on a social phenomenon that an important page will have more other pages linking to it. Additional improvement to this algorithm is mostly done inside Google or a few other big search engine companies.

Ranking of product pages is still an ongoing task faced by most E-commerce companies. There is no inherent linking among these pages as they are all generated internally. Therefore PageRank cannot be used here. But there is other information we can explore

  1. Syntactic correlation between query and pages retrieved
  2. Search by other users on similar product and their clicks after ranking results were presented (confirmation from those users)
  3. The behavior (such as pages visited, visit sequence) of current user

Item 1 is measured by TF-IDF (Term frequency and Inverse Document frequency), and cosine similarity.

Item 2 is measured by correlation between a query and most frequently clicked pages. This can be built by mining user search logs.

Item 3 is measured by page correlation between visited pages and retrieved product pages. Potentially some classifier can be built from visited pages and visiting sequence mapped to a category (of query type), then such category can be directly applied to rank the resulting product pages. The classifier can be trained on all user log, where certain click stream leads to final product page click or product purchase. Since we are building classifier, other information about the user can be thrown into the model: gender, age group, geographical region, income level and so on. These user specific information are not easy to get and may not increase much prediction power.

The third type of ranking is advertisement display. Assume you give user correct results (optimally ranked) on your page, how would you display advertisement next to these results? This is similar to ranking product pages, in the sense there is no inherent PageRank among advertisement items. Therefore the methods applied to product page ranking can also apply to advertisement ranking, namely get similarity between query and ads page, get historical data on confirmed results, get mapping between user clicks and ads click. Advertisement brings some new dimension such as auction bids (price) they paid for these keywords (or simple stated preference on these keywords), and clickthrough on these ads. The goal of ads display is not highest relevancy, but highest total revenue from all the ads. In general, this assumes advertisers already take care of relevance issue.

Sometimes we have to match ads with non-search pages, for example, news page from user click, email page, social networking pages and so on. This is called “contextual advertisement”, where there are no explicit keywords for advertiser to bid on. The content provider has to decide which ad to display.

Giving the rapidly growing data on the Internet, the field of information retrieval will keep growing. It is an exciting time to be in this field and create new enabling technology.


[2] The first full-scale web search engine W3CCatalog was released in 1993.

[3] Amazon was founded in 1994.

[4] See Wikipedia entry on PageRank:

Fierce competition in mobile navigation

When you search for “navigator” or “navigation” in iPhone App store, more than 9 different apps from various companies would show up. At least 9 companies are competing in this market. All of them provide voice guide. Majority of them have real human voice, and a few low-priced one use Text to Speech (TTS). Below is a list of these 9 major competing GPS navigators on iPhones:

Navigation Application Price frequency of  charge Voice
VoxTrek $2.99 once TTS
MotionX GPS (by FullPower) $2.99 monthly  
MapQuest Navigator $3.99 monthly  
Gokivo $4.99 monthly  
AT&T Navigator (from Telenav) $9.99 monthly  
CoPilot Live $29.99 once  
NDrive $32.99 once TTS
TomTom $59.99 once  
Navigon $79.99 once  

As we can see from the above table, price for mobile navigation has dramatically decreased. MotionX’s $2.99 per month is less than one third of charge from AT&T offer. The pricing model is also moving toward a monthly subscription instead of one-time purchase. This is good for consumers who only spend a small amount of money to try out. It is good for app providers who can update the feature and data for the navigation. The monthly subscription model will be the future to stay. In addition, some providers offer 30-day free trial, which is very attractive for the uncertain buyer.

The graphical interface on these navigators varies widely. From color, road sign to direction arrow, each app is inventing its unique way of enticing the user. Some navigators is apparently over-loaded with signs and hard to interpret. Another crucial factor for user purchase is

starting page, before user reaches navigation page. This pages gives user the ability to change settings, add addresses and so on. If the starting page is too complex, the user would normally be overwhelmed and would go away.

It will take the next 1-2 years to see how the mobile navigation war plays out. Given that the voice-guided navigation is similar across different product (nice voice and relatively correct route guides, and similar speed of rerouting), the main differentiating factors will be price and user interface. As for navigation quality, it is hard to judge and may not vary much among these apps. For consumers, this is excellent news. With such affordable price, it won’t be long when everyone’s cell phone is equipped with a navigator