Decentralized Exchange : Explaining Makers, Takers and the missing piece

To explain makers and takers concept I would take help of Mary Maker and Terry Taker. Mary wants to buy ( or sell ) BXL token ( Blockx Labs token ). Mary creates BXL Order doesn’t matter buy or sell. This makes Mary maker for the Exchange. Terry who just came back reading important announcements about Blockx Labs sees and interested in completing the order. Terry accepts the order and becomes Taker for the exchange.

To be identified as maker or taker buying or selling does not matter but if participant is creating or accepting the order. Generally speaking adding or taking liquidity. Liquidity creator is Maker and liquidity reducer is the Taker.

Centralized Exchange

In above example Mary created example absorbed by Central Software. If anyone wants to trade they have to talk to this Central Software. Central Software makes exchange centralized. While blockchain is running on tens of thousands of node a central server runs on way less nodes, possible only 1 server. Central server is generally owned by person or single entity. Such entity can be scrutiny and forced to censorship. Central entity could be target of attack by malicious group of people, country easily. Hence decentralized exchange provides more freedom and universal participation.

Decentralized flow

Everybody is running Central Book. Mary publishes to Terry and all other participants Central Book directly. When Terry accepts the order settlement happens on blockchain directly. All participants completes the trade without any Central Book.

Complications in Decentralized Flow

If Mary wants to sell BLX and Terry agrees. Terry would send Ether to Mary but Mary maliciously refuses to send BLX. The trust is missing and immediate settlement is missing. This is the missing piece of decentralized exchange.

Conclusion

Participant creating liquidity to the exchange is making the market hence he/she is the Maker. Otherwise participant is removing the liquidity hence he/she is the Taker. While centralized exchange provides trust limited by censorship and on hacker’s target, the decentralized exchange has a problem to solve for trustless participants.

VR enables visiting MARS

NASA dropped Curiosity Rover on Mars year 2012. Since then Curiosity has been hiking and capturing photos like a savvy traveler.

NASA partnering with Google enabled visiting Mars with new hyped technology Virtual Reality. Virtual Reality creates near real visual experience and more actual engagement.

Project is ready for general masses at https://accessmars.withgoogle.com/

With Access to Mars project Google and NASA creates virtual Mars with images taken by Curiosity Rover. However few images are gray and others are full RGB. Mostly due to Curiosity does not need to take high quality images all the time and skimming can be performed with enough accuracy with low accuracy. You can travel Mars with similar experience to Google Street View or access Curiosity's mission locations by clicking on specific icons.

Check it out again at https://accessmars.withgoogle.com/

Miami Dolphin owner responded to Donald Trump

People with high position responds with cleverness, thoughtfulness, smartness and compassion, except few.

Owner of Miami Dolphin has responded to racial slur whirling United States of America. Here is his tweet.

Statement from Miami Dolphins Owner and Founder of Ross Initiative in Sports for Equality (RISE) Stephen Ross. pic.twitter.com/6W3mXwJO6M

— Miami Dolphins (@MiamiDolphins) September 23, 2017

What is Ethereum

Ethereum is a distributed application based on Blockchain Technology. That does not answer all questions.

I found many blocks that manages to compare and contract Ethereum and Bitcoin and praises possibilities with Ethereum but in nutshell it's an engine that can rotate an axle.

From rotating axle you can build factories, trains, cars or anything else, but you need an engine, that's Ethereum.

Explaining more with examples Ethereum will be used as Platform for digital currencies, distributed ledger simply anything that needs event log / ledger / daily diary / log book.

Security, distributed nature etc can very well be achieved with other Peer to Peer technologies.

A Note on Serverless Architecture or FaaS

 Serverless architecture allows app owner to run process anywhere. Serverless architectures works with run-replenish pattern of application development. A service that wakes up and sleeps after logic is executed is a Serverless App / Service.

The provisioning is on demand for application . Application may run on shared or physical hardware and application runs in isolation to other processes. FaaS - Function as a service is new coined term accordance with SaaS and PaaS and many other *aaS. FaaS will be a useful pattern in microservices and related world.

FaaS will provide portable implementations. Auto Scale with increased usage and painless expansion managed by provider

Business Advantages
 - Time to market reduced
 - Cost to market is reduced
 - Experimentation is key and happening
 - Help save some trees by saving unnecessary CPU cycles

Drawbacks on Serverless architecture
   - Non Transnational
   - Third Party application coding
   - Hype, may need to have a realization curve
   - Discovery of such applications is difficult.
   - Operational issues : Deployment procedure needs modification.
   - Operational Issues : Packaging. Each vendor may required specific binding to logs, dependencies, code, startup
   - Operational Issues : Versioning of application is difficult
 - Implementations
   - Azure Functions
   - Web Tasks
   - Google Functions
   - Firebase
   - AWS Lambda
  

Amazon Lowering prices for Whole Foods

Amazon bough whole foods months back. Amazon has been figuring out many ways to capture grocery market for long time. Now they have a shot at it.

Amazon is known for their specific tactics to enhance market prices. Whether its Amazon Web Services or Amazon.com or pricing Kindle. Amazon is a good competitor to market and brings aggressive competition to market.

Recently it came to notice that Amazon is going to police lower prices for Whole Foods.

https://www.usatoday.com/story/money/2017/08/25/amazon-prime-members-perks-whole-foods-organic-natural-deals-prices/602204001/

These changes are interesting and would be of specific interest to Amazon Prime members. Amazon is planning to add special prices for their Prime members. Whether this prices are US only or North America or All Regions, that's something only time can tell.

See more information at below link :
https://twitter.com/USATODAY?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor

Tensorflow Adds Java, C, Go Lang Support

Tensorflow is well known library for Deep Learning created by Google. Recently Tensorflow moved from 1.0 to 1.2. In this journey there we many architectural changes in Tensorflow library. I have gone through many Github libraries that cannot be ran because of version differences. I hope all major changes are done and future releases are more functional additions than incompatible refactoring.

Recently Tensorflow also added support for Java, C and Go lang. I can guess some reasons but not sure if Google can confirm so.

Java is a good additional. A lot of Enterprise infrastructure supports Java. It would be very useful to train the model in Python and load the same in Java. Normally Data Scientist and Deep Learning Engineers more familiarity with Python hence training is very production part of Model Development. However running the same model in production is better with Java and could give nicer edge to Tensorflow to its adoption.

Adding Go is on the same line as Java however the support seems more fine tuned to people who would like to run Deep Learning model at a very large scale. It could be a lot of savings in terms of time and infrastructure cost.

For addition of C Language was little surprise to me. However it look a little time to understand why. I am not iOS developer however I did play around with some development for iPad. Hence I believe addition of C Language was to ensure model trained on Python could run on iOS which is second largest mobile market after Android.

I am surprised to see there is no support for R language so far, but I hope it will be added soon enough. Also Microsoft is supporting R language very well so it could be tug of war between these giants to understand and build next platform and which language to choose.

Concluding supporting a lot of languages is not very new. Every big data framework is trying to be language independent atleast access and productionalizing point of view.

Kotlin Examples

Google announcement has created sparse interest in Kotlin. Kotlin being Java / JVM Wapper concept could get wide acceptance and has potential to be top 5 languages.

Here I am covering some Kotlin examples I came across :

Kotlin Sevlet Example with Simple Hello World with rest and Java Sevelet. Thebuild platform be Gradle The could be found here.

A more advanced application with Kotlin and web example is needed. Spring has been core component of Java Ecosystem. With Gradle build system and Spring boot the example could be found here. This example is also restful and could serve as basic skeleton for projects.

It's easy to get started with Kotlin using their documentation. However if you are interested a developer's take on the subject then this link could be useful. Covering major high level constructs to build your knowledge base.  I also found Kotlin Practical Exmaple blog to be useful at the little lower level constructs.

Java 8 without Lambdas to print elements using short hand

Goal
Print all elements in List with Java 8 without Lambdas and a short hand input.

Setup
In following code lets fill in the blanks to print all elements of given list.

@Test

    public void SimpleCollection() {

        List values = Arrays.asList(1, 2, 3, 4, 5, 6);

        values.forEach(/* fill the code here */);

    }

Solution

As the solution is small and trivial the output looks as follows.

@Test

    public void SimpleCollection() {

        List values = Arrays.asList(1, 2, 3, 4, 5, 6);

        values.forEach(System.out::println);

    }

Java 8 with lambda expression to print elements on screen

Goal

Using Java 8 and its new feature Lambdas lets print each element of List to screen.

Setup

We will start with following code and fill in to a piece of logic to push elements on console.

@Test

    public void SimpleCollection() {

        List values = Arrays.asList(1, 2, 3, 4, 5, 6);

        values.forEach(/* fill with lambda expression */);

    }

Goal

We will a lambda expression e -> {/** code block **/} to manage the output logic. Something like this

value -> {

            System.out.println(value);

        }

The complete solution looks like following

@Test

    public void SimpleCollection() {

        List values = Arrays.asList(1, 2, 3, 4, 5, 6);

        values.forEach(value -> {

            System.out.println(value);

        });

    }

Java 8 For Each with Consumer example

Goal
Java 8 comes with new features which adds forEach and Consumer to its list. Lets write a simple piece of code that uses forEach and Consumer<> to print the elements on screen.

Setup
Following code is given to us and need to fill in the blank to print the elements.

@Test

    public void SimpleCollection() {

        List values = Arrays.asList(1, 2, 3, 4, 5, 6);

        values.forEach(/** fill with Consumer and print to screen.**/

);

    }

Solution

We can use follwing code to fill in the blank. This code uses Consumer and implements the method accept(). In accept() we can write any piece of logic. Here we will simply print elements on screen.

new Consumer() {

            public void accept(Integer value) {

                System.out.println(value);

            }

The complete program looks like as following :

@Test

    public void SimpleCollection() {

        List values = Arrays.asList(1, 2, 3, 4, 5, 6);

        values.forEach(new Consumer() {

            public void accept(Integer value) {

                System.out.println(value);

            }

        });

    }

Sort Collection using sort function and Java 8

Goal
Sorting is widely used in daily routine to modify data arrangement. In this blog the input is a list of alphabets. Using Java 8 and new sort method. This blog introduces List.sort() as a small example.

Setup
Lets start with following code. As shown it prints unsorted array elements.

         @Test

    public void testCollectionSorted() {

        List list = Arrays.asList("b", "f", "e", "a");

        

        // print each elements of list object

        list.forEach(input -> System.out.println(input));

    }

Solution

Now we will use List.sort() and pass a lambda expression which will sort the list

list.sort((e1, e2) -> {

            return e1.compareTo(e2);

        });

Thats it. Here is the full method which can be used to sort and print array contains alphabets.

         @Test

    public void testCollectionSorted() {

        

        List list = Arrays.asList("b", "f", "e", "a");

        list.sort((e1, e2) -> {

            return e1.compareTo(e2);

        });

        list.forEach(input -> System.out.println(input));

}

Hello World in Java

In this blogpost I will show you how to write SIMPLE hello world program in Java using command line.

On Windows :
> Type cmd in start
> in cmd type notepad press enter
> In notepad type following



> Save the notepad to cmd's present working directory
> execute javac "filename.java"
> execute java -classpath . filename.class
> Output should be "Hello World!"

Have fun .. this is just a sample blog......

Handling screen resolution problem after installing ubuntu

>> Changing Screen resolution :

Somtime ubuntu does not recognize correct resolution for the screen. But we can always make it up. Execute following steps in order to change screen resolution are you are interested in :

1) Screen resolutions that my screen can adjust to are :
   - 1280x1024
   - 1680x1050

2) Adding a new resolution starts with getting the right configurations for that resolution.
  - (todo: write cvt command here )

3) Execute : xrandr --newmode "1680x1050_60.00"  146.25  1680 1784 1960 2240  1050 1053 1059 1089 -hsync +vsync

This will create a resolution entry in the file

4) Now add the resolution to GUI for changing resolution :

xrandr --addmode VGA-0 1680x1050_60.00

5) There must be an option to change to this resolution in the GUI. Go check and change to that GUI if interested ...

>> Installing JAVA
 
$ sudo apt-get install openjdk-6-jdk

>> Installing BUILD ESSENTIALS

$ sudo apt-get install build-essential

>> Installing Apache

$sudo apt-get install apache2

Few useful commands :
sudo /etc/init.d/apache2 restart
sudo /etc/init.d/apache2 start
sudo /etc/init.d/apache2 stop

Go to http://localhost in your browser and should get "It Works" message from Apache.

>> Installing PHP

sudo apt-get install php5 libapache2-mod-php5

Restart apache
sudo /etc/init.d/apache2 restart

Check if PHP is installed correctly 
sudo gedit /var/www/testphp.php
Write "" and save the file.

Go to following location in browser :
http://localhost/testphp.php

This will display PHP information on the webpage.

>> Installing MySQL 

sudo apt-get install mysql-server

Remember the passsword for mysql-server as root.

Now install php tool to edit MySQL .

sudo apt-get install libapache2-mod-auth-mysql php5-mysql phpmyadmin


Configuration file is at /etc/mysql/my.cnf

Useful Softwares

SuperPutty : http://code.google.com/p/superputty/
JvmStat
JD : Java Decompiler

Hadoop - Forrester Report

AWS is feature rich ?? Need to check it out.
 Forrester claiming AWS is feature rich. I dont know how.

hadoop modelling : MR, Pig, Mahout
Storage and Data MGMT : HDFS, HBase, Cassandra
Data warehousing,summarization, query : Hive, Sqoop
Data Collection / Aggregation / analysis : Chukwa, Flume
metadata/table/schema : HCatalog
Cluster mgmt/job sched/workflow : zookeeper, oozie, Ambari
Hadoop Data Serialization : Avro


Good News : Hadoop is full of immature products

Hadoop productions  :
MapR = Strong OEM, feature rich ( why feature rich )
HortonWorks : Efficient echo system, everything
Penhaho : BI tool for big data, works on thrid party hadoop clusters
DataMeer : Hadoop modelling tool ( a modelling tool for nonrelational database .. LOL )

Companies involving hadoop :
Composite Software, Concurrent, Dell, Endeca, Hadapt, HP/Vertica,Informatica, NetApp, Microsoft, Oracle, Pervasive, Platfora, Quest Software, RainStor, SAP/Sybase, SGI,and StackIQ. Karmasphere and Teradata/Aster Data,
Forrester : HStreaming, Outerthought, Zettaset, Platform Computing, Pentaho, Datameer, DataStax, HortonWOrks, Cloudera, MapR, GreenPlum, EMC, IBM, AWS

Compare Apache Wicket vs Vaadin

Here is the stackoverflow blog that I found which compare wicket and Vaadin.

If you are not interested in reading the whole forum then understand that Wicket has more advantages than Vaadin. Vaadin has advantages of beautiful themes but wicket can integrate with GWT.

Vaadin is better if  you just want to stick with java and not interested in CSS or javascript. But if you put in your resume that you are a web developer but not good at CSS or JavaScript then it automatically turns against you. So Vaadin wont be advantageous here. While using Wicket comes with some skills required to imagine the GUI. For developers designing GUI is also useful virtue. Does not need to be flashy but certainly useful GUI rocks.

If desktop look and feel is needed then Vaadin is good as I already suggested, but wicket is no less. You can use GWT to create such look and feels.

datasets

This site links to various dataset across the federal government.

www.Data.gov -- repository for data and geodata from across the federal government, searchable by agency, data type, keyword, among others. Many, but not all Commerce data sets reside here.

http://www.data.gov/metric

Data.gov Commerce Data and tools can be found at

Data
http://www.data.gov/list/agency/1/0/catalog/raw/page/1/count/50

Tools
http://www.data.gov/list/agency/1/0/catalog/tools/page/1/count/50

Census Data – Population, household, housing, demographics. Economic census and monthly indicators, foreign trade, employment statistics, maps, geographic data and more. http://www.census.gov/
http://www.census.gov/main/www/access.html

List of Open Data Sites Around the World: http://www.data.gov/opendatasites
Amazon Listing of Public Data Sets: http://aws.amazon.com/datasets
Washington DC: http://data.octo.dc.gov
New York: http://nyc.gov/data
San Francisco: http://datasf.org/
U.K.: http://data.gov.uk/

http://www.cs.cmu.edu/~awm/10701/project/data.html

Convert Excel to CSV

Following VBScript works for following problem statement :
- Convert Excel to CSV
- If Excel has multiple sheets save them as ..csv
- Convert all the files in specified directory ( i.e. C:\ )

Dim oFSO
Dim oShell, oExcel, oFile, oSheet
Set oFSO = CreateObject("Scripting.FileSystemObject")
Set oShell = CreateObject("WScript.Shell")
Set oExcel = CreateObject("Excel.Application")
oExcel.DisplayAlerts = False

For Each oFile In oFSO.GetFolder("C:\\drop\\MarketShare\\2010").Files
 WScript.echo "Hello"
 If LCase(oFSO.GetExtensionName(oFile)) = "xls" Then
   WScript.echo oFile
   With oExcel.Workbooks.Open(oFile, 0, True, , , , True, , , , False, , False)
     For Each oSheet In .Worksheets
       oSheet.SaveAs "C:\drop\MarketShare\2010\" & oFile.Name & "." & oSheet.Name & ".csv", 6
     Next
     .Close False, , False
   End With
 End If
Next
oExcel.Quit
oShell.Popup "Conversion complete", 10

Little or Big

execute following command on linux shell :
$ echo -n I | od -to2 | head -n1 | cut -f2 -d" " | cut -c6

if the output is 1 then its big endian otherwise its little endian.

Resource : http://serverfault.com/questions/163487/linux-how-to-tell-if-system-is-big-endian-or-little-endian