About



My name is Hafidz Zulkifli. I am a data scientist based in KL, Malaysia.

Since 2008, I've worked across multiple telecom domains such mediation and OSS, covering multiple responsibilities such as requirement elicitation, solutions development, testing, and delivery. From time to time I was also roped in to provide support in pre sales activities.

More recently, I have been getting hands dirty on a few big data analytics projects; ranging from use cases that relates to user mobility across continents to understanding the dynamics of communities within a neighbourhood.

On this site I write about my experiences and challenges across those years, both as a reminder to myself and a note to others with similar interest. Talking about interest, mine are mostly in startups, social enterprise and artificial intelligence. I also do woodwork from time to time.

For any job related queries, opportunities, or maybe you just felt like having a teh tarik session with me - I'm contactable via LinkedIn or my email at ikanez[at]gmail.com. 

Popular posts from this blog

HIVE: Both Left and Right Aliases Encountered in Join

Recently was stuck on this error while trying to do a JOIN in HIVE. Below is my SQL create table ma.internet_v2 as select A.msisdn, A.imsi, A.dt, A.start_time, A.end_time, A.url, A.ttl_connection_dur_ms, A.ttl_upload_bytes, A.ttl_download_bytes, A.ttl_cdr_cnt, coalesce(B.domain_desc,A.domain_desc) domain_desc, coalesce(B.subdomain_desc, A.subdomain_desc) subdomain_desc from db.internet A left outer join hfz_domain_name_mapping B on instr(A.url, B.url_pattern) > 0; HIVE then give me and error message "Both Left and Right Aliases Encountered in Join". After going through some mail threads it seems that HIVE can support certain types of join. Only equality joins, outer joins, and left semi joins are supported in Hive. Hive does not support join conditions that are not equality conditions as it is very difficult to express such conditions as a map/reduce job. A poster from  Stack Overflow  suggested that one should use WHERE instead of ON. Duly following his advice,
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Changing Windows Account password using Outlook

http://theessentialexchange.com/blogs/michael/archive/2007/11/24/changing-user-passwords-with-outlook-2003-2007.aspx . 1) Call the helpdesk - the most likely scenario if you are not in a hosted environment 2) Use the control panel - most Hosted Exchange providers provide a function on a user's control panel enabling the user to change their password, using the functionality in item (3). Most large companies will implement a similar capability for their users. Small companies will likely need to implement item (3) directly or their helpdesk will do it (as in item 1). 3) Enable IISADMPWD - use KB 555071 to enable the use of a web page to allow changing the password of an active directory user.
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A Basic Recipe for Machine Learning

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Ever since wrapping up the three Deep Learning courses by Andrew Ng I've been meaning to write down some of the gems that he's highlighted throughout the course. One of the nice ones that I felt needed to be written down is his general recipe to approaching a deep learning algorithm/model. I've basically summarized it in a flowchart below (because everybody loves a flowchart right?) Basic deep learning recipe What is bias and variance? The below diagram is the typical explanation that I'm sure most of us are used to.  Graphical illustration of bias and variance How can we know if we have high bias or high variance?  For high bias, we could take a look at the training set performance. A poor performance is an indicator of a poor model fit, and signals that we could try to apply a bigger network to get a better fit of the model. For high variance, we could take a look at the validation set (or dev set - as Andrew calls it) performance.
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