Author Archive

Ten Commandments for Good Teaching

November 23rd, 2010 Comments off

By Yale Patt. Good for future instructors as well as good students.

My Ten Commandments for Good Teaching – Know the material – Want to teach – Genuinely respect your students and show it – Set the bar high; students will measure up – Emphasize understanding; de-emphasize memorization – Take responsibility for what is covered – Dont even try to cover the material – Encourage interruptions; dont be afraid to digress – Dont forget those three little words – Reserved for future use

via Ten Commandments for Good Teaching.

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Paper accepted for DATE 2012 in Grenoble, France

November 21st, 2010 Comments off

The HPC lab will present a paper in DATE (Design Automation and Test in Europe) — a premier conference on design automation. The title of the paper is “I2CRF: Incremental Interconnect Customization for Embedded Reconfigurable Fabrics”, and is about how to do design specialization to exploit the characteristics of application domain in the context of reconfigurable computing.

Conference website:

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Feds Plot Near Human Robot Docs, Farmers, Troops | News | Communications of the ACM

October 25th, 2010 Comments off

Feds Plot Near Human Robot Docs, Farmers, Troops

Maybe robot is the next big thing after five decades of IT revolution?

via Feds Plot Near Human Robot Docs, Farmers, Troops | News | Communications of the ACM (summary).

via WIRED (original post)

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Memory-Aware Mapping for Reconfigurable Architectures

October 13th, 2010 Comments off

We presented a first approach to optimizing software for the memory architecture of the target reconfigurable computing system, in HiPEAC 2010, held in Pisa, Italy. The motivation of this work is that often in multimedia applications the performance bottleneck is in data transfer, not in computation per se. While previously we have tried only to maximize computation rate only, it may be better to sacrifice computation rate a little to increase data transfer rate if there is a trade-off between computation and data transfer as in the case of CGRA mapping. We targeted our compiler for a ADRES-like architecture, with a slightly simplified local memory subsystem:  double-buffered, multi-banked, and the banks of the local memory are one-to-one mapped to the load-store units of the reconfigurable architecture.

Coarse-Grained Reconfigurable Arrays (CGRAs) are a very promising platform, providing both, up to 10-100 MOps/mW of power efficiency and are software programmable. However, this cardinal promise of CGRAs critically hinges on the effectiveness of application mapping onto CGRA platforms. While previous solutions have greatly improved the computation speed, they have largely ignored the impact of the local memory architecture on the achievable power and performance. This paper motivates the need for memory-aware application mapping for CGRAs, and proposes an effective solution for application mapping that considers the effects of various memory architecture parameters including the number of banks, local memory size, and the communication bandwidth between the local memory and the external main memory. Our proposed solution achieves 62% reduction in the energy-delay product, which factors into about 47% and 28% reduction in the energy consumption and runtime, respectively, as compared to memory-unaware mapping for realistic local memory architectures. We also show that our scheme scales across a range of applications, and memory parameters.

Read the full paper: “Memory-Aware Application Mapping on Coarse-Grained Reconfigurable Arrays,” Lecture Notes in Computer Science (HiPEAC ’10), Vol. 5952, pp. 171-185, by Yongjoo Kim, Jongeun Lee, Aviral Shrivastava, Jonghee W. Yoon and Yunheung Paek, 2010.

Categories: Publications Tags: , ,

20 Linux Server Hardening Security Tips

September 28th, 2010 Comments off

Recommended for SysAdmins:

20 Linux Server Hardening Security Tips.

Why recommend?  i) New & valuable information (nothing obvious), ii) Detailed instructions (mostly) for those who may not be familiar, iii) Written well (writing style does not appear to be a personal blog, but an article of some magazine).

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Inspiring Quote – Nothing is done

September 19th, 2010 Comments off

Nothings is done. Everything in the world remains to be done or done over.

The greatest picture is not yet painted, the greatest play isn’t written, the greatest poem is unsung. There isn’t in all the world a perfect railroad, nor a good government, nor a sound law. Physics, mathematics, and especially the most advanced and exact of the sciences, are being fundamentally revised. Chemistry is just becoming a science; psychology, economics, and sociology are awaiting a Darwin, whose work in turn awaiting an Einstein.

If the rah-rah boys in our colleges could be told this, they might not all be specialists in football, parties, and unearned degrees. They are not told it, however; they are told to learn what is known. This is nothing.

(Lincoln Steffens, 1931)
(quoted from How to Get Ideas by Jack Foster)

This was said about 80 years ago! Yet, it is still relevant today. This quote was something that I have wanted to tell my students if I ever get a chance to…

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Hybrid supercomputer in Los Alamos Nat’l Lab.

September 16th, 2010 Comments off

Scientists want faster, more powerful high-performance supercomputers to simulate complex physical, biological, and socioeconomic systems with greater realism and predictive power. In May, Los Alamos scientists doubled the processing speed of the previously fastest computer.Roadrunner, a new hybrid supercomputer, uses a video game chip to propel performance to petaflop/s speeds capable of more than a thousand trillion calculations per second.”The computer is a speed demon. It will allow us to solve tremendous problems,” said Thomas DAgostino, head of the National Nuclear Security Administration, which oversees nuclear weapons research and maintains the warhead stockpile.The computer might also have many medical and science applications, including developing biofuels or discovering drug therapies.

Continue reading: Computing::Worlds Fastest Computer::Los Alamos Lab.

Categories: Review Tags: ,

Short Review – Eliminating microarchitectural dependency from Architectural Vulnerability

September 14th, 2010 Comments off

There is a paper that is very closely related to our work on RFV. Question is how do they differ?

First terminology. Microarchitecture-level masking is  hardware-dependent portion whereas architecture-level masking is software-dependent. Then AVF captures both, while their PVF is claimed to capture only the latter. “Therefore,  PVF  is  impacted  only  by changes  to  the  binary  or  to  input  data  and  not  by changes in hardware.” That’s it. It does not really say about how to statically estimate the PVF without actually running the program.

But this paper is important in that it establishes the needs for our static estimation techniques.

The architectural vulnerability factor (AVF) of a hardware structure is the probability that a fault in the structure will affect the output of a program. AVF captures both microarchitectural and architectural fault masking effects; therefore, AVF measurements cannot generate insight into the vulnerability of software independent of hardware. To evaluate the behavior of software in the presence of hardware faults, we must isolate the software-dependent (architecture-level masking) portion of AVF from the hardware-dependent (microarchitecture-level masking) portion, providing a quantitative basis to make reliability decisions about software independent of hardware. In this work, we demonstrate that the new program vulnerability factor (PVF) metric provides such a basis: PVF captures the architecture-level fault masking inherent in a program, allowing software designers to make quantitative statements about a program’s tolerance to soft errors. PVF can also explain the AVF behavior of a program when executed on hardware; PVF captures the workload-driven changes in AVF for all structures. Finally, we demonstrate two practical uses for PVF: choosing algorithms and compiler optimizations to reduce a program’s failure rate.

by Sridharan, V.;   Kaeli, D.R.;
Dept. of Electr. & Comput. Eng., Northeastern Univ., Boston, MA

This paper appears in: High Performance Computer Architecture, 2009. HPCA 2009. IEEE 15th International Symposium on

via IEEE Xplore – Eliminating microarchitectural dependency from Architectural Vulnerability.

Categories: Review Tags: ,

Create a menu for private pages and posts in WordPress | ActiveCodeline

September 14th, 2010 Comments off

A feature to implement. We want to have member-only items in the top menu line. I think this is a fantastic idea. We’ll do this later..


Create a menu for private pages and posts in WordPress

Posted by branko in General | 14 Comments

Recently I was working on a project that required a members menu on sidebar. Idea was to mark some pages and posts in WordPress as a private ones. All those marked as private are not to be accessible to all others, unregistered users, or even some registered that do not belong to some assigned role. WordPress default behavior for posts and pages is not to show up on menu if you are not registered user, which is good. However, another WordPress default behavior is to show only private posts on sidebar menu while logged in. Meaning that pages marked as private do not show up on the menu when logged in. This is not so good. I needed a solution that will list private pages on my menu as well. After few minutes of unsuccessful Google search, i decided to write my own solution. It really wasn’t that difficult. It all came down to two existing WordPress functions, current_user_can(‘some_role’) and $wpdb->get_results($some_query).

/*show pages and post mixed on menu
$menu_type = post ->show posts only
$menu_type = page ->show pages only


if(current_user_can($user_role)) {

global $wpdb;
$html = null;

if($menu_type != 'all') {
$menu_query = "post_status='private' AND post_type='". $menu_type ."'";

else if($menu_type == 'all') {
$menu_query = "post_status='private'";

$query = "SELECT * FROM $wpdb->posts WHERE ". $menu_query;
$pages = $wpdb->get_results($query);

$html .= '


return $html;


else {

$html = '

We are sorry, but only '. $user_role .' role user can access this area

# return $html;
return false;

via Create a menu for private pages and posts in WordPress | ActiveCodeline.

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Lab homepage open!

September 13th, 2010 1 comment

Thanks to many people who have contributed to this homepage, with ideas/suggestion or actual work.
Also feel free to give any new suggestions you may have about this homepage. 🙂

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