high density - Page 55 - Developer IT

Help me vaildate these points regarding Ruby

- by Bragaadeesh

Hi, I have started learning Ruby for the past 2,3 weeks and I have come up with some findings on the language. Can someone please validate these points. Implemented in many other high level languages such as C, Java, .Net etc., Is slow for the obvious reason that it cannot beat any of the already known high level languages. Should never be compared with any other high level language. Not suitable for large applications. Completely open source and is in a budding state. Has a framework called Rails which claims that it would be good for Agile development Community out there is getting better day by day and finding help immediately should not be a problem as time goes by. Has significant changes between releases which many developers wont welcome right away. Running time cannot be comprehensively estimated since the language has several underlying implementation in several languages. Books are always outdated by the time when you finish them. Thanks.

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simple collision detection with box2dweb

- by skywalker

im beginner in box2dweb that version of box2d for javascript i wrote simple gravity system and i want to detect the collision between the box and the ground , when the falling box hit the ground execute simple function like function sucs(){alert("the box on the floor !")}; this is my code var CANVAS_WIDTH = 1024, CANVAS_HEIGHT = 700, SCALE = 30; var b2Vec2 = Box2D.Common.Math.b2Vec2 , b2BodyDef = Box2D.Dynamics.b2BodyDef , b2Body = Box2D.Dynamics.b2Body , b2FixtureDef = Box2D.Dynamics.b2FixtureDef , b2Fixture = Box2D.Dynamics.b2Fixture , b2World = Box2D.Dynamics.b2World , b2MassData = Box2D.Collision.Shapes.b2MassData , b2PolygonShape = Box2D.Collision.Shapes.b2PolygonShape , b2CircleShape = Box2D.Collision.Shapes.b2CircleShape , b2DebugDraw = Box2D.Dynamics.b2DebugDraw; var canvas = document.getElementById("canvas"); var context = canvas.getContext("2d"); var world = new b2World(new b2Vec2(0, 8), true); var fixDef = new b2FixtureDef(); var bodyDef = new b2BodyDef(); fixDef.density = 1.0; fixDef.friction = 0.5; bodyDef.type = b2Body.b2_staticBody; fixDef.shape = new b2PolygonShape; fixDef.shape.SetAsBox(20, 2); bodyDef.position.Set(10, 400 / 30 + 1.8); world.CreateBody(bodyDef).CreateFixture(fixDef); fixDef.density = 1.0; fixDef.friction = 0.5; fixDef.restitution = 0.3; bodyDef.type = b2Body.b2_dynamicBody; bodyDef.position.Set(50 / SCALE, 0 / SCALE); //bodyDef.linearVelocity.Set((Math.random() * 12) + 2, (Math.random() * 12) + 2); fixDef.shape = new b2PolygonShape(); fixDef.shape.SetAsBox(25 / SCALE, 25 / SCALE); world.CreateBody(bodyDef).CreateFixture(fixDef); var debugDraw = new b2DebugDraw(); debugDraw.SetSprite(document.getElementById("canvas").getContext("2d")); debugDraw.SetDrawScale(30.0); debugDraw.SetFillAlpha(0.5); debugDraw.SetLineThickness(1.0); debugDraw.SetFlags(b2DebugDraw.e_shapeBit | b2DebugDraw.e_jointBit); world.SetDebugDraw(debugDraw); var image = new Image(); image.src = "image.png"; window.setInterval(gameLoop, 1000 / 60); function gameLoop() { world.Step(1 / 60, 8, 3); world.ClearForces(); context.clearRect(0, 0, CANVAS_WIDTH, CANVAS_HEIGHT); b = world.GetBodyList() var pos = b.GetPosition(); context.save(); context.translate(pos.x * SCALE, pos.y * SCALE); context.rotate(b.GetAngle()); context.drawImage(image, -25, -25); context.restore(); b = b.GetNext(); pos = b.GetPosition(); context.save(); context.translate(pos.x * SCALE, pos.y * SCALE); //b.GetAngle()++; context.rotate(b.GetAngle()); context.drawImage(image, -25, -25); context.restore(); world.DrawDebugData(); };

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All libGDX input statements are returning TRUE at once

- by MowDownJoe

I'm fooling around with Box2D and libGDX and running into a peculiar problem with polling for input. Here's the code for the Screen's render() loop: @Override public void render(float delta) { Gdx.gl20.glClearColor(0, 0, .2f, 1); Gdx.gl20.glClear(GL20.GL_COLOR_BUFFER_BIT); camera.update(); game.batch.setProjectionMatrix(camera.combined); debugRenderer.render(world, camera.combined); if(Gdx.input.isButtonPressed(Keys.LEFT)){ Gdx.app.log("Input", "Left is being pressed."); pushyThingyBody.applyForceToCenter(-10f, 0); } if(Gdx.input.isButtonPressed(Keys.RIGHT)){ Gdx.app.log("Input", "Right is being pressed."); pushyThingyBody.applyForceToCenter(10f, 0); } world.step((1f/45f), 6, 2); } And the constructor is largely just setting up the World, Box2DDebugRenderer, and all the Bodies in the world: public SandBox(PhysicsSandboxGame game) { this.game = game; camera = new OrthographicCamera(800, 480); camera.setToOrtho(false); world = new World(new Vector2(0, -9.8f), true); debugRenderer = new Box2DDebugRenderer(); BodyDef bodyDef = new BodyDef(); bodyDef.type = BodyType.DynamicBody; bodyDef.position.set(100, 300); body = world.createBody(bodyDef); CircleShape circle = new CircleShape(); circle.setRadius(6f); FixtureDef fixtureDef = new FixtureDef(); fixtureDef.shape = circle; fixtureDef.density = .5f; fixtureDef.friction = .4f; fixtureDef.restitution = .6f; fixture = body.createFixture(fixtureDef); circle.dispose(); BodyDef groundBodyDef = new BodyDef(); groundBodyDef.position.set(new Vector2(0, 10)); groundBody = world.createBody(groundBodyDef); PolygonShape groundBox = new PolygonShape(); groundBox.setAsBox(camera.viewportWidth, 10f); groundBody.createFixture(groundBox, 0f); groundBox.dispose(); BodyDef pushyThingyBodyDef = new BodyDef(); pushyThingyBodyDef.type = BodyType.DynamicBody; pushyThingyBodyDef.position.set(new Vector2(400, 30)); pushyThingyBody = world.createBody(pushyThingyBodyDef); PolygonShape pushyThingyShape = new PolygonShape(); pushyThingyShape.setAsBox(40f, 10f); FixtureDef pushyThingyFixtureDef = new FixtureDef(); pushyThingyFixtureDef.shape = pushyThingyShape; pushyThingyFixtureDef.density = .4f; pushyThingyFixtureDef.friction = .1f; pushyThingyFixtureDef.restitution = .5f; pushyFixture = pushyThingyBody.createFixture(pushyThingyFixtureDef); pushyThingyShape.dispose(); } Testing this on the desktop. Basically, whenever I hit the appropriate keys, neither of the if statements in the loop return true. However, when I click in the window, both statements return true, resulting in a 0 net force on the body. Why is this?

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VirtualBox 3.2 is released! A Red Letter Day?

- by Fat Bloke

Big news today! A new release of VirtualBox packed full of innovation and improvements. Over the next few weeks we'll take a closer look at some of these new features in a lot more depth, but today we'll whet your appetite with the headline descriptions. To start with, we should point out that this is the first Oracle-branded version which makes today a real Red-letter day ;-) Oracle VM VirtualBox 3.2 Version 3.2 moves VirtualBox forward in 3 main areas ( handily, all beginning with "P" ) : performance, power and supported guest operating system platforms. Let's take a look: Performance New Latest Intel hardware support - Harnessing the latest in chip-level support for virtualization, VirtualBox 3.2 supports new Intel Core i5 and i7 processor and Intel Xeon processor 5600 Series support for Unrestricted Guest Execution bringing faster boot times for everything from Windows to Solaris guests; New Large Page support - Reducing the size and overhead of key system resources, Large Page support delivers increased performance by enabling faster lookups and shorter table creation times. New In-hypervisor Networking - Significant optimization of the networking subsystem has reduced context switching between guests and host, increasing network throughput by up to 25%. New New Storage I/O subsystem - VirtualBox 3.2 offers a completely re-worked virtual disk subsystem which utilizes asynchronous I/O to achieve high-performance whilst maintaining high data integrity; New Remote Video Acceleration - The unique built-in VirtualBox Remote Display Protocol (VRDP), which is primarily used in virtual desktop infrastructure deployments, has been enhanced to deliver video acceleration. This delivers a rich user experience coupled with reduced computational expense, which is vital when servers are running hundreds of virtual machines; Power New Page Fusion - Traditional Page Sharing techniques have suffered from long and expensive cache construction as pages are scrutinized as candidates for de-duplication. Taking a smarter approach, VirtualBox Page Fusion uses intelligence in the guest virtual machine to determine much more rapidly and accurately those pages which can be eliminated thereby increasing the capacity or vm density of the system; New Memory Ballooning- Ballooning provides another method to increase vm density by allowing the memory of one guest to be recouped and made available to others; New Multiple Virtual Monitors - VirtualBox 3.2 now supports multi-headed virtual machines with up to 8 virtual monitors attached to a guest. Each virtual monitor can be a host window, or be mapped to the hosts physical monitors; New Hot-plug CPU's - Modern operating systems such Windows Server 2008 x64 Data Center Edition or the latest Linux server platforms allow CPUs to be dynamically inserted into a system to provide incremental computing power while the system is running. Version 3.2 introduces support for Hot-plug vCPUs, allowing VirtualBox virtual machines to be given more power, with zero-downtime of the guest; New Virtual SAS Controller - VirtualBox 3.2 now offers a virtual SAS controller, enabling it to run the most demanding of high-end guests; New Online Snapshot Merging - Snapshots are powerful but can eat up disk space and need to be pruned from time to time. Historically, machines have needed to be turned off to delete or merge snapshots but with VirtualBox 3.2 this operation can be done whilst the machines are running. This allows sophisticated system management with minimal interruption of operations; New OVF Enhancements - VirtualBox has supported the OVF standard for virtual machine portability for some time. Now with 3.2, VirtualBox specific configuration data is also stored in the standard allowing richer virtual machine definitions without compromising portability; New Guest Automation - The Guest Automation APIs allow host-based logic to drive operations in the guest; Platforms New USB Keyboard and Mouse - Support more guests that require USB input devices; New Oracle Enterprise Linux 5.5 - Support for the latest version of Oracle's flagship Linux platform; New Ubuntu 10.04 ("Lucid Lynx") - Support for both the desktop and server version of the popular Ubuntu Linux distribution; And as a man once said, "just one more thing" ... New Mac OS X (experimental) - On Apple hardware only, support for creating virtual machines run Mac OS X. All in all this is a pretty powerful release packed full of innovation and speedups. So what are you waiting for? -FB

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Investigating on xVelocity (VertiPaq) column size

- by Marco Russo (SQLBI)

In January I published an article about how to optimize high cardinality columns in VertiPaq. In the meantime, VertiPaq has been rebranded to xVelocity: the official name is now “xVelocity in-memory analytics engine (VertiPaq)” but using xVelocity and VertiPaq when we talk about Analysis Services has the same meaning. In this post I’ll show how to investigate on columns size of an existing Tabular database so that you can find the most important columns to be optimized. A first approach can be looking in the DataDir of Analysis Services and look for the folder containing the database. Then, look for the biggest files in all subfolders and you will find the name of a file that contains the name of the most expensive column. However, this heuristic process is not very optimized. A better approach is using a DMV that provides the exact information. For example, by using the following query (open SSMS, open an MDX query on the database you are interested to and execute it) you will see all database objects sorted by used size in a descending way. SELECT * FROM $SYSTEM.DISCOVER_STORAGE_TABLE_COLUMN_SEGMENTS ORDER BY used_size DESC You can look at the first rows in order to understand what are the most expensive columns in your tabular model. The interesting data provided are: TABLE_ID: it is the name of the object – it can be also a dictionary or an index COLUMN_ID: it is the column name the object belongs to – you can also see ID_TO_POS and POS_TO_ID in case they refer to internal indexes RECORDS_COUNT: it is the number of rows in the column USED_SIZE: it is the used memory for the object By looking at the ration between USED_SIZE and RECORDS_COUNT you can understand what you can do in order to optimize your tabular model. Your options are: Remove the column. Yes, if it contains data you will never use in a query, simply remove the column from the tabular model Change granularity. If you are tracking time and you included milliseconds but seconds would be enough, round the data source column to the nearest second. If you have a floating point number but two decimals are good enough (i.e. the temperature), round the number to the nearest decimal is relevant to you. Split the column. Create two or more columns that have to be combined together in order to produce the original value. This technique is described in VertiPaq optimization article. Sort the table by that column. When you read the data source, you might consider sorting data by this column, so that the compression will be more efficient. However, this technique works better on columns that don’t have too many distinct values and you will probably move the problem to another column. Sorting data starting from the lower density columns (those with a few number of distinct values) and going to higher density columns (those with high cardinality) is the technique that provides the best compression ratio. After the optimization you should be able to reduce the used size and improve the count/size ration you measured before. If you are interested in a longer discussion about internal storage in VertiPaq and you want understand why this approach can save you space (and time), you can attend my 24 Hours of PASS session “VertiPaq Under the Hood” on March 21 at 08:00 GMT.

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Investigating on xVelocity (VertiPaq) column size

- by Marco Russo (SQLBI)

In January I published an article about how to optimize high cardinality columns in VertiPaq. In the meantime, VertiPaq has been rebranded to xVelocity: the official name is now “xVelocity in-memory analytics engine (VertiPaq)” but using xVelocity and VertiPaq when we talk about Analysis Services has the same meaning. In this post I’ll show how to investigate on columns size of an existing Tabular database so that you can find the most important columns to be optimized. A first approach can be looking in the DataDir of Analysis Services and look for the folder containing the database. Then, look for the biggest files in all subfolders and you will find the name of a file that contains the name of the most expensive column. However, this heuristic process is not very optimized. A better approach is using a DMV that provides the exact information. For example, by using the following query (open SSMS, open an MDX query on the database you are interested to and execute it) you will see all database objects sorted by used size in a descending way. SELECT * FROM $SYSTEM.DISCOVER_STORAGE_TABLE_COLUMN_SEGMENTS ORDER BY used_size DESC You can look at the first rows in order to understand what are the most expensive columns in your tabular model. The interesting data provided are: TABLE_ID: it is the name of the object – it can be also a dictionary or an index COLUMN_ID: it is the column name the object belongs to – you can also see ID_TO_POS and POS_TO_ID in case they refer to internal indexes RECORDS_COUNT: it is the number of rows in the column USED_SIZE: it is the used memory for the object By looking at the ration between USED_SIZE and RECORDS_COUNT you can understand what you can do in order to optimize your tabular model. Your options are: Remove the column. Yes, if it contains data you will never use in a query, simply remove the column from the tabular model Change granularity. If you are tracking time and you included milliseconds but seconds would be enough, round the data source column to the nearest second. If you have a floating point number but two decimals are good enough (i.e. the temperature), round the number to the nearest decimal is relevant to you. Split the column. Create two or more columns that have to be combined together in order to produce the original value. This technique is described in VertiPaq optimization article. Sort the table by that column. When you read the data source, you might consider sorting data by this column, so that the compression will be more efficient. However, this technique works better on columns that don’t have too many distinct values and you will probably move the problem to another column. Sorting data starting from the lower density columns (those with a few number of distinct values) and going to higher density columns (those with high cardinality) is the technique that provides the best compression ratio. After the optimization you should be able to reduce the used size and improve the count/size ration you measured before. If you are interested in a longer discussion about internal storage in VertiPaq and you want understand why this approach can save you space (and time), you can attend my 24 Hours of PASS session “VertiPaq Under the Hood” on March 21 at 08:00 GMT.

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Good examples of MapServer / OpenLayers

- by MarkJ

I want to convince some clients to use MapServer and OpenLayers. Please can anyone suggest attractive websites to show off the possiblities! The clients will be impressed by: A density map (otherwise known as a heat map, colour-shaded grid coverage, contour plot...). The ability for the user to download the underlying data for the density map, restricted to the area being viewed, in some format such as netCDF. Standard OpenLayers stuff. Zooming, panning, scale bar, overview map... Different base layers. Could be WMS, Google, Bing... Searching for a placename, map is panned to display the place. MapServer.org seems to be down right now :( But from memory their examples didn't have the "wow" factor. The OpenLayers examples demonstrate only one or two features per example - I want something to wow the clients by showing all the capabilities in one example. PS If you have good examples that use some other open source tools, post them by all means. But just JavaScript please: customer says no rich client.

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Fitting Gaussian KDE in numpy/scipy in Python

- by user248237

I am fitting a Gaussian kernel density estimator to a variable that is the difference of two vectors, called "diff", as follows: gaussian_kde_covfact(diff, smoothing_param) -- where gaussian_kde_covfact is defined as: class gaussian_kde_covfact(stats.gaussian_kde): def __init__(self, dataset, covfact = 'scotts'): self.covfact = covfact scipy.stats.gaussian_kde.__init__(self, dataset) def _compute_covariance_(self): '''not used''' self.inv_cov = np.linalg.inv(self.covariance) self._norm_factor = sqrt(np.linalg.det(2*np.pi*self.covariance)) * self.n def covariance_factor(self): if self.covfact in ['sc', 'scotts']: return self.scotts_factor() if self.covfact in ['si', 'silverman']: return self.silverman_factor() elif self.covfact: return float(self.covfact) else: raise ValueError, \ 'covariance factor has to be scotts, silverman or a number' def reset_covfact(self, covfact): self.covfact = covfact self.covariance_factor() self._compute_covariance() This works, but there is an edge case where the diff is a vector of all 0s. In that case, I get the error: File "/srv/pkg/python/python-packages/python26/scipy/scipy-0.7.1/lib/python2.6/site-packages/scipy/stats/kde.py", line 334, in _compute_covariance self.inv_cov = linalg.inv(self.covariance) File "/srv/pkg/python/python-packages/python26/scipy/scipy-0.7.1/lib/python2.6/site-packages/scipy/linalg/basic.py", line 382, in inv if info>0: raise LinAlgError, "singular matrix" numpy.linalg.linalg.LinAlgError: singular matrix What's a way to get around this? In this case, I'd like it to return a density that's essentially peaked completely at a difference of 0, with no mass everywhere else. thanks.

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AndEngine Physics Editor loading level

- by Khawar Raza

I have created a .pes file using PhysicsEditor and imported as xml and have added to my project. When I parsed it and created bodies, it is showing strange behavior. The mapping of bodies that I created in PhysicsEditor is totally different what I see in my application means the shapes I draw in PhysicsEditor are rendering differently in my app. Here is my xml and code to parse and add bodies to scene. PhysicsEditor XML file: <?xml version="1.0" encoding="UTF-8"?>  <bodydef version="1.0"> <bodies numBodies="1"> <body name="car_path" dynamic="false" numFixtures="1"> <fixture density="2" friction="1" restitution="0" filter_categoryBits="1" filter_groupIndex="0" filter_maskBits="65535" isSensor="false" type="POLYGON" numPolygons="20" > <polygon numVertexes="6"> <vertex x="277.0000" y="152.0000" /> <vertex x="356.0000" y="172.0000" /> <vertex x="413.0000" y="194.0000" /> <vertex x="476.0000" y="223.0000" /> <vertex x="173.0000" y="232.0000" /> <vertex x="174.0000" y="148.0000" /> </polygon> <polygon numVertexes="4"> <vertex x="1556.0000" y="221.0000" /> <vertex x="1142.0000" y="94.0000" /> <vertex x="1255.0000" y="-15.0000" /> <vertex x="1554.0000" y="-14.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="-192.0000" y="177.0000" /> <vertex x="-888.0000" y="139.0000" /> <vertex x="-549.0000" y="-125.0000" /> </polygon> <polygon numVertexes="6"> <vertex x="1762.0000" y="24.0000" /> <vertex x="1862.0000" y="27.0000" /> <vertex x="1927.0000" y="68.0000" /> <vertex x="2078.0000" y="222.0000" /> <vertex x="1643.0000" y="212.0000" /> <vertex x="1642.0000" y="38.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="-1150.0000" y="146.0000" /> <vertex x="-1776.0000" y="140.0000" /> <vertex x="-1476.0000" y="-25.0000" /> </polygon> <polygon numVertexes="4"> <vertex x="-2799.0000" y="103.0000" /> <vertex x="-2684.0000" y="223.0000" /> <vertex x="-3112.0000" y="256.0000" /> <vertex x="-3108.0000" y="98.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="3112.0000" y="255.0000" /> <vertex x="2422.0000" y="222.0000" /> <vertex x="3120.0000" y="-71.0000" /> </polygon> <polygon numVertexes="4"> <vertex x="1142.0000" y="94.0000" /> <vertex x="1556.0000" y="221.0000" /> <vertex x="709.0000" y="226.0000" /> <vertex x="911.0000" y="93.0000" /> </polygon> <polygon numVertexes="6"> <vertex x="-2111.0000" y="89.0000" /> <vertex x="-2067.0000" y="94.0000" /> <vertex x="-2002.0000" y="139.0000" /> <vertex x="-2344.0000" y="223.0000" /> <vertex x="-2196.0000" y="112.0000" /> <vertex x="-2153.0000" y="91.0000" /> </polygon> <polygon numVertexes="4"> <vertex x="105.0000" y="233.0000" /> <vertex x="-94.0000" y="178.0000" /> <vertex x="69.0000" y="106.0000" /> <vertex x="91.0000" y="104.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="-2002.0000" y="139.0000" /> <vertex x="-2067.0000" y="94.0000" /> <vertex x="-2032.0000" y="110.0000" /> </polygon> <polygon numVertexes="4"> <vertex x="-1150.0000" y="146.0000" /> <vertex x="105.0000" y="233.0000" /> <vertex x="-2344.0000" y="223.0000" /> <vertex x="-2002.0000" y="139.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="413.0000" y="194.0000" /> <vertex x="356.0000" y="172.0000" /> <vertex x="376.0000" y="176.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="105.0000" y="233.0000" /> <vertex x="-192.0000" y="177.0000" /> <vertex x="-94.0000" y="178.0000" /> </polygon> <polygon numVertexes="4"> <vertex x="105.0000" y="233.0000" /> <vertex x="-1150.0000" y="146.0000" /> <vertex x="-888.0000" y="139.0000" /> <vertex x="-192.0000" y="177.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="3112.0000" y="255.0000" /> <vertex x="-3112.0000" y="256.0000" /> <vertex x="-2684.0000" y="223.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="3112.0000" y="255.0000" /> <vertex x="1556.0000" y="221.0000" /> <vertex x="1643.0000" y="212.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="709.0000" y="226.0000" /> <vertex x="173.0000" y="232.0000" /> <vertex x="476.0000" y="223.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="3112.0000" y="255.0000" /> <vertex x="2078.0000" y="222.0000" /> <vertex x="2422.0000" y="222.0000" /> </polygon> <polygon numVertexes="3"> <vertex x="3112.0000" y="255.0000" /> <vertex x="105.0000" y="233.0000" /> <vertex x="173.0000" y="232.0000" /> </polygon> </fixture> </body> </bodies> <metadata> <format>1</format> <ptm_ratio></ptm_ratio> </metadata> </bodydef> And here is my code: private void loadLevel() { // TODO Auto-generated method stub AssetManager assetManager = getAssets(); try { InputStream stream = assetManager.open("tmx/path1.xml"); if(stream != null) { try { DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); dbf.setValidating(false); dbf.setIgnoringComments(false); dbf.setIgnoringElementContentWhitespace(true); dbf.setNamespaceAware(true); DocumentBuilder db = null; db = dbf.newDocumentBuilder(); Document document = db.parse(stream); Element root = document.getDocumentElement(); NodeList bodiesNodeList = root.getElementsByTagName("bodies"); for(int i = 0; i < bodiesNodeList.getLength(); i++) { BodyDef bodyDef = new BodyDef(); bodyDef.type = BodyType.StaticBody; bodyDef.fixedRotation = true; Element bodiesElement = (Element)bodiesNodeList.item(i); NodeList bodyList = bodiesElement.getElementsByTagName("body"); for(int j = 0; j < bodyList.getLength(); j++) { Element bodyElement = (Element)bodyList.item(j); Body body = mPhysicsWorld.createBody(bodyDef); NodeList fixtureList = bodyElement.getElementsByTagName("fixture"); for(int k = 0; k < fixtureList.getLength(); k++) { Element fixtureElement = (Element)fixtureList.item(k); FixtureDef fixtureDef = new FixtureDef(); if(fixtureElement != null) { String density = fixtureElement.getAttribute("density"); String friction = fixtureElement.getAttribute("friction"); String restitution = fixtureElement.getAttribute("restitution"); fixtureDef = PhysicsFactory.createFixtureDef(Float.parseFloat(density), Float.parseFloat(friction), Float.parseFloat(restitution)); } NodeList polygonList = fixtureElement.getElementsByTagName("polygon"); if(polygonList != null && polygonList.getLength() > 0) { for(int m = 0; m < polygonList.getLength(); m++) { PolygonShape polyShape = new PolygonShape(); Element polygonElement = (Element)polygonList.item(m); NodeList vertexList = polygonElement.getElementsByTagName("vertex"); if(vertexList != null && vertexList.getLength() > 0) { Vector2 [] vectors = new Vector2[vertexList.getLength()]; for(int n = 0; n < vertexList.getLength(); n++) { Element vertexElement = (Element)vertexList.item(n); if(vertexElement != null) { float x = Float.parseFloat(vertexElement.getAttribute("x")); float y = Float.parseFloat(vertexElement.getAttribute("y")); vectors[n] = new Vector2(x/PIXEL_TO_METER_RATIO_DEFAULT, y/PIXEL_TO_METER_RATIO_DEFAULT); } } polyShape.set(vectors); fixtureDef.shape = polyShape; } body.createFixture(fixtureDef); } } } mScene.attachChild(bgSprite); mPhysicsWorld.registerPhysicsConnector(new PhysicsConnector(bgSprite, body, false, false)); } } } catch(Exception e) { e.printStackTrace(); } } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } Any idea where I am going wrong?

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How to set the position of a sprite within a box2d body?

- by Frank

Basically I have 2 polygons for my body. When I add a sprite for userData, the position of the texture isn't where I want it to be. What I want to do is adjust the position of the texture within the body. Here's the code sample of where I am setting this: CCSpriteSheet *sheet = (CCSpriteSheet*) [self getChildByTag:kTagSpriteSheet]; CCSprite *pigeonSprite = [CCSprite spriteWithSpriteSheet:sheet rect:CGRectMake(0,0,40,32)]; [sheet addChild:pigeonSprite z:0 tag:kPigeonSprite]; pigeonSprite.position = ccp( p.x, p.y); bodyDef.position.Set(p.x/PTM_RATIO, p.y/PTM_RATIO); bodyDef.userData = sprite; b2Body *body = world->CreateBody(&bodyDef); b2CircleShape dynamicCircle; dynamicCircle.m_radius = .25f; dynamicCircle.m_p.Set(0.0f, 1.0f); // Define the dynamic body fixture. b2FixtureDef circleDef; circleDef.shape = &dynamicCircle; circleDef.density = 1.0f; circleDef.friction = 0.3f; body->CreateFixture(&circleDef); b2Vec2 vertices[3]; vertices[0].Set(-0.5f, 0.0f); vertices[1].Set(0.5f, 0.0f); vertices[2].Set(0.0f, 1.0f); b2PolygonShape triangle; triangle.Set(vertices, 3); b2FixtureDef triangleDef1; triangleDef1.shape = &triangle; triangleDef1.density = 1.0f; triangleDef1.friction = 0.3f; body->CreateFixture(&triangleDef1);

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Why should the "prime-based" hashcode implmentation be used instead of the "naive" one?

- by Wilhelm

I have seen that a prime number implmentation of the GetHashCode function is being recommend, for example here. However using the following code (in VB, sorry), it seems as if that implementation gives the same hash density as a "naive" xor implementation. If the density is the same, I would suppose there is the same probability of cllision in both implementations. Am I missing anything on why is the prime approach preferred? I am supossing that if the hash code is a byte I do not lose generality for the integer case. Sub Main() Dim XorHashes(255) As Integer Dim PrimeHashes(255) As Integer For i = 0 To 255 For j = 0 To 255 For k = 0 To 255 XorHashes(GetXorHash(i, j, k)) += 1 PrimeHashes(GetPrimeHash(i, j, k)) += 1 Next Next Next For i = 0 To 255 Console.WriteLine("{0}: {1}, {2}", i, XorHashes(i), PrimeHashes(i)) Next Console.ReadKey() End Sub Public Function GetXorHash(ByVal valueOne As Integer, ByVal valueTwo As Integer, ByVal valueThree As Integer) As Byte Return CByte((valueOne Xor valueTwo Xor valueThree) Mod 256) End Function Public Function GetPrimeHash(ByVal valueOne As Integer, ByVal valueTwo As Integer, ByVal valueThree As Integer) As Byte Dim TempHash = 17 TempHash = 31 * TempHash + valueOne TempHash = 31 * TempHash + valueTwo TempHash = 31 * TempHash + valueThree Return CByte(TempHash Mod 256) End Function

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Sparse (Pseudo) Infinite Grid Data Structure for Web Game

- by Ming

I'm considering trying to make a game that takes place on an essentially infinite grid. The grid is very sparse. Certain small regions of relatively high density. Relatively few isolated nonempty cells. The amount of the grid in use is too large to implement naively but probably smallish by "big data" standards (I'm not trying to map the Internet or anything like that) This needs to be easy to persist. Here are the operations I may want to perform (reasonably efficiently) on this grid: Ask for some small rectangular region of cells and all their contents (a player's current neighborhood) Set individual cells or blit small regions (the player is making a move) Ask for the rough shape or outline/silhouette of some larger rectangular regions (a world map or region preview) Find some regions with approximately a given density (player spawning location) Approximate shortest path through gaps of at most some small constant empty spaces per hop (it's OK to be a bad approximation often, but not OK to keep heading the wrong direction searching) Approximate convex hull for a region Here's the catch: I want to do this in a web app. That is, I would prefer to use existing data storage (perhaps in the form of a relational database) and relatively little external dependency (preferably avoiding the need for a persistent process). Guys, what advice can you give me on actually implementing this? How would you do this if the web-app restrictions weren't in place? How would you modify that if they were? Thanks a lot, everyone!

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Add gridlines to a output plot in Mathemaitca

- by xslittlegrass

I'm trying to add gridlines to a output density plot in Mathematica. The plot is generated by a long calculation in Mathematica and when I do the plot I forget to add the Mesh-True options. I don't want to do all the calculation and generate the plot again since it takes a long time. Is that possible to add the gridlines or mesh lines to plot ONLY using the output plot at hand? For example, If I have a plot p. Is it possible to add the mesh lines ONLY manipulate p? In a ordinary one dimensional plot, this will work p1 = Plot[Sin[x], {x, -3, 3}]; Insert[p1, GridLines -> Automatic, -1] But when I try the density plot, it seems the gridlines is always under the plot, and can be seen only at the image margin area. p2 = DensityPlot[Sin[x + y^2], {x, -3, 3}, {y, -2, 2}, PlotRangePadding -> 0.2]; Insert[p2, GridLines -> Automatic, -1] Updata The Mesh option on the output plot will not work because Mesh is not a options of a Graphics: Show[p2,Mesh->True] will give a message "an unrecoginzed option name(Mesh) was encountered while rendering a Graphics" Thanks.

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Does the "Supporting Multiple Screens" document contradict itself?

- by Neil Traft

In the Supporting Multiple Screens document in the Android Dev Guide, some example screen configurations are given. One of them states that the small-ldpi designation is given to QVGA (240x320) screens with a physical size of 2.6"-3.0". According to this DPI calculator, a 2.8" QVGA display equates to 143 dpi. However, further down the page the document explicitly states that all screens over 140 dpi are considered "medium" density. So which is it, ldpi or mdpi? Is this a mistake? Does anyone know what the HTC Tattoo or similar device actually reports? I don't have access to any devices like this. Also, with the recent publishing of this document, I'm glad to see we finally have an explicit statement of the exact DPI ranges of the three density categories. But why haven't we been given the same for the small, medium, and large screen size categories? I'd like to know the exact ranges for all these. Thanks in advance for your help!

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Choropleth mapping issue in R

- by chasec

I am trying to follow the tutorial described here: http://www.thisisthegreenroom.com/2009/choropleths-in-r/ The below code executes, but it is either not matching my dataset with the maps_counties data properly, or it isn't plotting it in the order I would expect. For example, the resulting areas for the greater NYC area show no density while random counties in PA show the highest density. The general format of my data table is: county state count fairfield connecticut 17 hartford connecticut 6 litchfield connecticut 3 new haven connecticut 12 ... ... westchester new york 70 yates new york 1 luzerne pennsylvania 1 Note this data is in order by state and then county and includes data for CT, NJ, NY, & PA. First, I read in my data set: library(maps) library(RColorBrewer) d <- read.table("gissum.txt", sep="\t", header=TRUE) #Concatenate state and county info to match maps library d$stcon <- paste(d$state, d$county, sep=",") #Color bins colors = brewer.pal(5, "PuBu") d$colorBuckets <- as.factor(as.numeric(cut(d$count,c(0,10,20,30,40,50,300)))) Here is my matching mapnames <- map("county",plot=FALSE)[4]$names colorsmatched <- d$colorBuckets [na.omit(match(mapnames ,d$stcon))] Plotting: map("county" ,c("new york","new jersey", "connecticut", "pennsylvania") ,col = colors[d$colorBuckets[na.omit(match(mapnames ,d$stcon))]] ,fill = TRUE ,resolution = 0 ,lty = 0 ,lwd= 0.5 ) map("state" ,c("new york","new jersey", "connecticut", "pennsylvania") ,col = "black" ,fill=FALSE ,add=TRUE ,lty=1 ,lwd=2 ) map("county" ,c("new york","new jersey", "connecticut", "pennsylvania") ,col = "black" ,fill=FALSE ,add=TRUE , lty=1 , lwd=.5 ) title(main="Respondent Home ZIP Codes by County") I am sure I am missing something basic re: the order in which the maps function plots items - but I can't seem to figure it out. Thanks for the help. Please let me know if you need any more information.

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Which Android hardware devices should I test on? [closed]

- by Tchami

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Oracle Announces New Oracle Exastack Program for ISV Partners

- by pfolgado

Oracle Exastack Program Enables ISV Partners to Leverage a Scalable, Integrated Infrastructure to Deliver Their Applications Tuned and Optimized for High-Performance News Facts Enabling Independent Software Vendors (ISVs) and other members of Oracle Partner Network (OPN) to rapidly build and deliver faster, more reliable applications to end customers, Oracle today introduced Oracle Exastack Ready, available now, and Oracle Exastack Optimized, available in fall 2011 through OPN. The Oracle Exastack Program focuses on helping ISVs run their solutions on Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud -- integrated systems in which the software and hardware are engineered to work together. These products provide partners with a lower cost and high performance infrastructure for database and application workloads across on-premise and cloud based environments. Leveraging the new Oracle Exastack Program in which applications can qualify as Oracle Exastack Ready or Oracle Exastack Optimized, partners can use available OPN resources to optimize their applications to run faster and more reliably -- providing increased performance to their end users. By deploying their applications on Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud, ISVs can reduce the cost, time and support complexities typically associated with building and maintaining a disparate application infrastructure -- enabling them to focus more on their core competencies, accelerating innovation and delivering superior value to customers. After qualifying their applications as Oracle Exastack Ready, partners can note to customers that their applications run on and support Oracle Exadata Database Machine and Oracle Exalogic Elastic Cloud component products including Oracle Solaris, Oracle Linux, Oracle Database and Oracle WebLogic Server. Customers can be confident when choosing a partner's Oracle Exastack Optimized application, knowing it has been tuned by the OPN member on Oracle Exadata Database Machine or Oracle Exalogic Elastic Cloud with a goal of delivering optimum speed, scalability and reliability. Partners participating in the Oracle Exastack Program can also leverage their Oracle Exastack Ready and Oracle Exastack Optimized applications to advance to Platinum or Diamond level in OPN. Oracle Exastack Programs Provide ISVs a Reliable, High-Performance Application Infrastructure With the Oracle Exastack Program ISVs have several options to qualify and tune their applications with Oracle Exastack, including: Oracle Exastack Ready: Oracle Exastack Ready provides qualifying partners with specific branding and promotional benefits based on their adoption of Oracle products. If a partner application supports the latest major release of one of these products, the partner may use the corresponding logo with their product marketing materials: Oracle Solaris Ready, Oracle Linux Ready, Oracle Database Ready, and Oracle WebLogic Ready. Oracle Exastack Ready is available to OPN members at the Gold level or above. Additionally, OPN members participating in the program can leverage their Oracle Exastack Ready applications toward advancement to the Platinum or Diamond levels in the OPN Specialized program and toward achieving Oracle Exastack Optimized status. Oracle Exastack Optimized: When available, for OPN members at the Gold level or above, Oracle Exastack Optimized will provide direct access to Oracle technical resources and dedicated Oracle Exastack lab environments so OPN members can test and tune their applications to deliver optimal performance and scalability on Oracle Exadata Database Machine or Oracle Exalogic Elastic Cloud. Oracle Exastack Optimized will provide OPN members with specific branding and promotional benefits including the use of the Oracle Exastack Optimized logo. OPN members participating in the program will also be able to leverage their Oracle Exastack Optimized applications toward advancement to Platinum or Diamond level in the OPN Specialized program. Oracle Exastack Labs and ISV Enablement: Dedicated Oracle Exastack lab environments and related technical enablement resources (including Guided Learning Paths and Boot Camps) will be available through OPN for OPN members to further their knowledge of Oracle Exastack offerings, and qualify their applications for Oracle Exastack Optimized or Oracle Exastack Ready. Oracle Exastack labs will be available to qualifying OPN members at the Gold level or above. Partners are eligible to participate in the Oracle Exastack Ready program immediately, which will help them meet the requirements to attain Oracle Exastack Optimized status in the future. Guidelines for Oracle Exastack Optimized, as well as Oracle Exastack Labs will be available in fall 2011. Supporting Quotes "In order to effectively differentiate their software applications in the marketplace, ISVs need to rapidly deliver new capabilities and performance improvements," said Judson Althoff, Oracle senior vice president of Worldwide Alliances and Channels and Embedded Sales. "With Oracle Exastack, ISVs have the ability to optimize and deploy their applications with a complete, integrated and cloud-ready infrastructure that will help them accelerate innovation, unlock new features and functionality, and deliver superior value to customers." "We view performance as absolutely critical and a key differentiator," said Tom Stock, SVP of Product Management, GoldenSource. "As a leading provider of enterprise data management solutions for securities and investment management firms, with Oracle Exadata Database Machine, we see an opportunity to notably improve data processing performance -- providing high quality 'golden copy' data in a reduced timeframe. Achieving Oracle Exastack Optimized status will be a stamp of approval that our solution will provide the performance and scalability that our customers demand." "As a leading provider of Revenue Intelligence solutions for telecommunications, media and entertainment service providers, our customers continually demand more readily accessible, enriched and pre-analyzed information to minimize their financial risks and maximize their margins," said Alon Aginsky, President and CEO of cVidya Networks. "Oracle Exastack enables our solutions to deliver the power, infrastructure, and innovation required to transform our customers' business operations and stay ahead of the game." Supporting Resources Oracle PartnerNetwork (OPN) Oracle Exastack Oracle Exastack Datasheet Judson Althoff blog Connect with the Oracle Partner community at OPN on Facebook, OPN on LinkedIn, OPN on YouTube, or OPN on Twitter

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Oracle Service Registry 11gR1 Support for Oracle Fusion Middleware/SOA Suite 11g PatchSet 2

- by Dave Berry

As you might be aware, a few days back we released Patchset 2 (PS2) for several products in the Oracle Fusion Middleware 11g Release 1 stack including WebLogic Server and SOA Suite. Though there was no patchset released for Oracle Service Registry (OSR) 11g, being an integral part of Fusion Middleware & SOA, OSR 11g R1 ( 11.1.1.2 ) is fully certified with this release. Below is some recommended reading before installing OSR 11g with the new PS2 : OSR 11g R1 & SOA Suite 11g PS2 in a Shared WebLogic Domain If you intend to deploy OSR 11g in the same domain as the SOA Suite 11g, the primary recommendation is to install OSR 11g in its own Managed Server within the same Weblogic Domain as the SOA Suite, as the following diagram depicts : An important pre-requisite for this setup is to apply Patch 9499508, after installation. It basically replaces a registry library - wasp.jar - in the registry application deployed on your server, so as to enable co-deployment of OSR 11g & SOA Suite 11g in the same WLS Domain. The patch fixes a java.lang.LinkageError: loader constraint violation that appears in your OSR system log and is now available for download. The second, equally important, pre-requisite is to modify the setDomainEnv.sh/.cmd file for your WebLogic Domain to conditionally set the CLASSPATH so that the oracle.soa.fabric.jar library is not included in it for the Managed Server(s) hosting OSR 11g. Both these pre-requisites and other OSR 11g Topology Best Practices are covered in detail in the new Knowledge Base article Oracle Service Registry 11g Topology : Best Practices. Architecting an OSR 11g High Availability Setup Typically you would want to create a High Availability (HA) OSR 11g setup, especially on your production system. The following illustrates the recommended topology. The article, Hands-on Guide to Creating an Oracle Service Registry 11g High-Availability Setup on Oracle WebLogic Server 11g on OTN provides step-by-step instructions for creating such an active-active HA setup of multiple OSR 11g nodes with a Load Balancer in an Oracle WebLogic Server cluster environment. Additional Info The OSR Home Page on OTN is the hub for OSR and is regularly updated with latest information, articles, white papers etc. For further reading, this FAQ answers some common questions on OSR. The OSR Certification Matrix lists the Application Servers, Databases, Artifact Storage Tools, Web Browsers, IDEs, etc... that OSR 11g is certified against. If you hit any problems during OSR 11g installation, design time or runtime, the first place to look into is the logs. To find more details about which logs to check when & where, take a look at Where to find Oracle Service Registry Logs? Finally, if you have any questions or problems, there are various ways to reach us - on the SOA Governance forum on OTN, on the Community Forums or by contacting Oracle Support. Yogesh Sontakke and Dave Berry

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Scrum for a single programmer?

- by Rob Perkins

I'm billed as the "Windows Expert" in my very small company, which consists of myself, a mechanical engineer working in a sales and training role, and the company's president, working in a design, development, and support role. My role is equally as general, but primarily I design and implement whatever programming on our product needs to get done in order for our stuff to run on whichever versions of Windows are current. I just finished watching a high-level overview of the Scrum paradigm, given in a webcast. My question is: Is it worth my time to learn more about this approach to product development, given that my development work items are usually given at a very high level, such as "internationalize and localize the product". If it is, how would you suggest adapting Scrum for the use of just one programmer? What tools, cloud-based or otherwise, would be useful to that end? If it is not, what approach would you suggest for a single programmer to organize his efforts from day to day? (Perhaps the question reduces to that simple question.)

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Ubuntu 12.04, Can hear the sound but Sound option in settings shows no sound card

- by Vivek Srivastava

I have weired issue. I did a fresh installation of Ubuntu 12.04. Then I installed Nvidia drives for my graphics card. I executed the command "modprobe nvidia" after installing the Nvidia drivers and rebooted. After reboot, sound indicator in top panel is disabled and I can't control the volume from there. I opened Settings Sound and it does not show any sound card installed. However, I can hear the sound. Please help. Output of lspci | grep Audio 00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 01) 01:00.1 Audio device: NVIDIA Corporation GF110 High Definition Audio Controller (rev a1) Output of lsmod | grep snd snd_hda_codec_hdmi 32191 4 snd_hda_codec_realtek 73851 1 snd_hda_intel 33367 0 snd_hda_codec 134156 3 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel snd_hwdep 13668 1 snd_hda_codec snd_pcm 97188 3 snd_hda_codec_hdmi,snd_hda_intel,snd_hda_codec snd_timer 29990 1 snd_pcm snd 78855 7 snd_hda_codec_hdmi,snd_hda_codec_realtek,snd_hda_intel,snd_hda_codec,snd_hwdep,snd_pcm,snd_timer soundcore 15091 1 snd snd_page_alloc 18529 2 snd_hda_intel,snd_pcm

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The Evolution of Link’s Swords [Wallpaper]

- by Jason Fitzpatrick

If you’re a fan of all things Legend of Zelda, this high-resolution wallpaper showcases all the swords from every Legend of Zelda game. In addition to the wallpaper that gathers all the swords together in one place, you can also check out the description on the wallpaper’s Deviant Art page to grab high-resolution images of each individual sword. Hit up the link below to grab both the wallpaper and the individual renderings. The Evolution of Link’s Swords [Deviant Art] 7 Ways To Free Up Hard Disk Space On Windows HTG Explains: How System Restore Works in Windows HTG Explains: How Antivirus Software Works

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Big Data – Role of Cloud Computing in Big Data – Day 11 of 21

- by Pinal Dave

In yesterday’s blog post we learned the importance of the NewSQL. In this article we will understand the role of Cloud in Big Data Story What is Cloud? Cloud is the biggest buzzword around from last few years. Everyone knows about the Cloud and it is extremely well defined online. In this article we will discuss cloud in the context of the Big Data. Cloud computing is a method of providing a shared computing resources to the application which requires dynamic resources. These resources include applications, computing, storage, networking, development and various deployment platforms. The fundamentals of the cloud computing are that it shares pretty much share all the resources and deliver to end users as a service. Examples of the Cloud Computing and Big Data are Google and Amazon.com. Both have fantastic Big Data offering with the help of the cloud. We will discuss this later in this blog post. There are two different Cloud Deployment Models: 1) The Public Cloud and 2) The Private Cloud Public Cloud Public Cloud is the cloud infrastructure build by commercial providers (Amazon, Rackspace etc.) creates a highly scalable data center that hides the complex infrastructure from the consumer and provides various services. Private Cloud Private Cloud is the cloud infrastructure build by a single organization where they are managing highly scalable data center internally. Here is the quick comparison between Public Cloud and Private Cloud from Wikipedia: Public Cloud Private Cloud Initial cost Typically zero Typically high Running cost Unpredictable Unpredictable Customization Impossible Possible Privacy No (Host has access to the data Yes Single sign-on Impossible Possible Scaling up Easy while within defined limits Laborious but no limits Hybrid Cloud Hybrid Cloud is the cloud infrastructure build with the composition of two or more clouds like public and private cloud. Hybrid cloud gives best of the both the world as it combines multiple cloud deployment models together. Cloud and Big Data – Common Characteristics There are many characteristics of the Cloud Architecture and Cloud Computing which are also essentially important for Big Data as well. They highly overlap and at many places it just makes sense to use the power of both the architecture and build a highly scalable framework. Here is the list of all the characteristics of cloud computing important in Big Data Scalability Elasticity Ad-hoc Resource Pooling Low Cost to Setup Infastructure Pay on Use or Pay as you Go Highly Available Leading Big Data Cloud Providers There are many players in Big Data Cloud but we will list a few of the known players in this list. Amazon Amazon is arguably the most popular Infrastructure as a Service (IaaS) provider. The history of how Amazon started in this business is very interesting. They started out with a massive infrastructure to support their own business. Gradually they figured out that their own resources are underutilized most of the time. They decided to get the maximum out of the resources they have and hence they launched their Amazon Elastic Compute Cloud (Amazon EC2) service in 2006. Their products have evolved a lot recently and now it is one of their primary business besides their retail selling. Amazon also offers Big Data services understand Amazon Web Services. Here is the list of the included services: Amazon Elastic MapReduce – It processes very high volumes of data Amazon DynammoDB – It is fully managed NoSQL (Not Only SQL) database service Amazon Simple Storage Services (S3) – A web-scale service designed to store and accommodate any amount of data Amazon High Performance Computing – It provides low-tenancy tuned high performance computing cluster Amazon RedShift – It is petabyte scale data warehousing service Google Though Google is known for Search Engine, we all know that it is much more than that. Google Compute Engine – It offers secure, flexible computing from energy efficient data centers Google Big Query – It allows SQL-like queries to run against large datasets Google Prediction API – It is a cloud based machine learning tool Other Players Besides Amazon and Google we also have other players in the Big Data market as well. Microsoft is also attempting Big Data with the Cloud with Microsoft Azure. Additionally Rackspace and NASA together have initiated OpenStack. The goal of Openstack is to provide a massively scaled, multitenant cloud that can run on any hardware. Thing to Watch The cloud based solutions provides a great integration with the Big Data’s story as well it is very economical to implement as well. However, there are few things one should be very careful when deploying Big Data on cloud solutions. Here is a list of a few things to watch: Data Integrity Initial Cost Recurring Cost Performance Data Access Security Location Compliance Every company have different approaches to Big Data and have different rules and regulations. Based on various factors, one can implement their own custom Big Data solution on a cloud. Tomorrow In tomorrow’s blog post we will discuss about various Operational Databases supporting Big Data. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Big Data, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL

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How do you decide site availability requirements?

- by Nathan Long

I work on a web application to file a specific kind of county taxes. Our company wants our state to mandate that counties must accept electronic filings (as opposed to paper) from any system that meets some sensible requirements for uptime, security, data validation, etc. (Yes, this would help us as a business, but it would also force county governments to be more efficient.) We're creating a draft of those requirements to be reviewed and tweaked with the state. One of the sections is "availability." We want to specify something reasonably high, but not so high that any unexpected problem will get us (or a competitor) penalized. How do we decide what's reasonable for availability requirements?

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Oracle’s Web Experience Management

- by Christie Flanagan

Today’s guest post on Oracle’s Web Experience Management comes from a member of our WebCenter Evangelist team, Noël Jaffré, a Principal Technologist based in France.Oracle’s Web Experience Management (WEM) solution enables organizations to optimize the online channel for driving marketing and customer experience management success. It empowers business users to manage the web presence and create rich and engaging online experiences for customers and prospects. Oracle's WEM platform provides a framework to simplify the integration of Oracle, third-party and custom-built applications. This framework essentially allows the creation and integration of applications using one single business interface called the WEM interface. It includes the following: Single sign-on access control for all integrated applications using the Central Authentication Service (CAS) component. A single centralized administration window for user, role, and native applications management including site management. Community server management, gadget server management as well as management for partner integrated technologies. A Representational State Transfer (REST) API for accessing WebCenter Sites data. REST services are supported on both Oracle WebCenter Sites and Oracle WebCenter Sites Satellite Server to leverage the satellite server cache. All REST requests are cached for web consuming applications as well for the high performance delivery of native applications on the mobile channel. Oracle WebCenter Sites’ Web Experience Management environment enables organizations to deliver a compelling online experience to customers by simplifying the deployment and management of sophisticated and engaging websites. The WebCenter Sites platform automates the entire process of managing web content including: Authoring: Business users can easily contribute and manage web content in real-time, with intuitive interfaces and drag-and-drop content authoring and layout capabilities designed for the non-technical user. Contextual Content Targeting: Marketers are empowered to create and manage targeted campaigns with relevant recommendations and promotions based on the context of the session of the visitor such as his or her navigation history, user profile, language, location or other information shared during the visitor session. Content Publishing and Deployment: It offers advanced multi-site management capabilities for departmental or regional sites, as well as strong multi-lingual and multi-locale content management. The remote satellite server caching infrastructure provides high-performance, distributed caching, tuned to deliver high-volume, targeted and multi-lingual sites. Analytics and Optimization: Business users and marketers have the ability to measure the effectiveness of their online content and campaigns at a granular level. Editors and marketers can immediately determine whether a given article or promotion is relevant to a particular customer segment. User-generated Content: Marketers can enable blogs, comments, rating and reviews on the website. All comments and reviews posted to the website can be moderated from the administrator interface either manually or automatically using filters, whitelists, blacklists or community based moderation. Personalized Gadget Dashboards: Site managers can deploy gadgets, small applications using web content, individually or as part of dashboards containing multiple gadgets. These gadget dashboards enable site visitors to create their own “MyPage” on a given site where they can select and customize the gadgets that the site administrator has made available. Any gadget that conforms to the iGoogle/OpenSocial standard can be made available to site visitors, or they can be created within the WEM interface. Oracle's WEM platform also provides a unique environment for the delivery of a rich, multichannel online experience for site visitors through its advanced management modules for mobile. With Oracle’s WEM solution, it’s easy to control branding and deliver a consistent message while repurposing web content for publication to mobile devices, kiosks and much more. This distinctive approach provides: HTML5 Delivery: HTML5 delivery which includes native support for adaptive design that responds to the user’s computer screen resolution and orientation. The approach is less driven by the particular hardware and more driven by the user’s interactions with the device. In other words, this approach takes both the screen interactions (either cursor or touch) and screen sizes and orientation into consideration. A Unique Native Mobile Extension Environment for Contributors: From the WEM interface, a contributor can directly manage their mobile channel, using the tooling already in place for driving the traditional web presence. This includes the mobile presentation, as well as mobile insite editing, drag and drop page layout, and in-context recommendations and personalization. Optimized REST APIs for High Performance Content Delivery on Native Mobile Device Applications: WebCenter Sites’ REST API uses the underlying HTTP methods (GET, POST, PUT, DELETE) to interact with resources. Resources support two types of input and output formats -- XML and JSON. REST calls are customizable to optimize the interactions between the content repositories and the client applications. Caching is essential to decrease network loads and improve overall reliability and usability of the applications and user interactions. REST results are cached through the highly efficient Oracle WebCenter Sites caching architecture.

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Digital Storage for Airline Entertainment

- by Bill Evjen

by Thomas Coughlin Common flash memory cards The most common flash memory products currently in use are SD cards and derivative products (e.g. mini and micro-SD cards) Some compact flash used for professional applications (such as DSLR cameras) Evolution of leading flash formats Standardization –> market expansion Market expansion –> volume iNAND –> focus is on enabling embedded X3 iSSD –> ideal for thin form factor devices Flash memory applications Phones are the #1 user of flash memory Flash memory is used as embedded and removable storage in many mobile applications Flash memory is being used in computers as USB sticks and SSDs Possible use of flash memory in computer combined with HDDs (hybrid HDDs and paired or dual storage computers) It can be a removable card or an embedded card These devices can only handle a specific number of writes Flash memory reads considerably quicker than hard drives Hybrid and dual storage in computers SSDs can provide fast performance but they are expensive HDDs can provide cheap storage but they are relatively slow Combining some flash memory with a HDD can provide costs close to those of HDDs and performance close to flash memory Seagate Momentus XT hybrid HDD Various dual storage offerings putting flash memory with HDDs Other common flash memory devices USB sticks All forms and colors Used for moving files around Some sold with content on them (Sony Movies on USB sticks) Solid State Drives (SSDs) Floating Gate Flash Memory Cell When a bit is programmed, electrons are stored upon the floating gate This has the effect of offsetting the charge on the control gate of the transistor If there is no charge upon the floating gate, then the control gate’s charge determines whether or not a current flows through the channel A strong charge on the control gate assumes that no current flows. A weak charge will allow a strong current to flow through. Similar to HDDs, flash memory must provide: Bit error correction Bad block management NAND and NOR memories are treated differently when it comes to managing wear In many NOR-based systems no management is used at all, since the NOR is simply used to store code, and data is stored in other devices. In this case, it would take a near-infinite amount of time for wear to become an issue since the only time the chip would see an erase/write cycle is when the code in the system is being upgraded, which rarely if ever happens over the life of a typical system. NAND is usually found in very different application than is NOR Flash memory wears out This is expected to get worse over time Retention: Disappearing data Bits fade away Retention decreases with increasing read/writes Bits may change when adjacent bits are read Time and traffic are concerns Controllers typically groom read disturb errors Like DRAM refresh Increases erase/write frequency Application characteristics Music – reads high / writes very low Video – r high / writes very low Internet Cache – r high / writes low On airplanes Many consumers now have their own content viewing devices – do they need the airlines? Is there a way to offer more to consumers, especially with their own viewers Additional special content tie into airplane network access to electrical power, internet Should there be fixed embedded or removable storage for on-board airline entertainment? Is there a way to leverage personal and airline viewers and content in new and entertaining ways?

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