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  • Altruistic network connection bandwidth estimation

    - by datenwolf
    Assume two peers Alice and Bob connected over a IP network. Alice and Bob are exchanging packets of lossy compressed data which are generated and to be consumes in real time (think a VoIP or video chat application). The service is designed to cope with as little bandwidth available, but relies on low latencies. Alice and Bob would mark their connection with an apropriate QoS profile. Alice and Bob want use a variable bitrate compression and would like to consume all of the leftover bandwidth available for the connection between them, but would voluntarily reduce the consumed bitrate depending on the state of the network. However they'd like to retain a stable link, i.e. avoid interruptions in their decoded data stream caused by congestion and the delay until the bandwidth got adjusted. However it is perfectly possible for them to loose a few packets. TL;DR: Alice and Bob want to implement a VoIP protocol from scratch, and are curious about bandwidth and congestion control. What papers and resources do you suggest for Alice and Bob to read? Mainly in the area of bandwidth estimation and congestion control.

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  • What kind of storage with two-way replication for multi site C# application?

    - by twk
    Hi I have a web-based system written using asp.net backed by mssql. A synchronized replica of this system is to be run on mobile locations and must be available regardless of the state of the connection to the main system (few hours long interruptions happens). For now I am using a copy of the main web application and a copy of the mssql server with merge replication to the main system. This works unreliably, and setting the replication is a pain. The amount of data the system contains is not huge, so I can migrate to different storage type. For the new version of this system I would like to implement a new replication system. I am considering migration to db4o for storage with it's replication support. I am thinking about other possible solutions like couchdb which had native replication support. I would like to stay with C#. Could you recommend a way to go for such a distributed environment? PS. Master-Slave replication is not an option: any side must be allowed to add/update data.

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  • How accurately (in terms of time) does Windows play audio?

    - by MusiGenesis
    Let's say I play a stereo WAV file with 317,520,000 samples, which is theoretically 1 hour long. Assuming no interruptions of the playback, will the file finish playing in exactly one hour, or is there some occasional tiny variation in the playback speed such that it would be slightly more or slightly less (by some number of milliseconds) than one hour? I am trying to synchronize animation with audio, and I am using a System.Diagnostics.Stopwatch to keep the frames matching the audio. But if the playback speed of WAV audio in Windows can vary slightly over time, then the audio will drift out of sync with the Stopwatch-driven animation. Which leads to a second question: it appears that a Stopwatch - while highly granular and accurate for short durations - runs slightly fast. On my laptop, a Stopwatch run for exactly 24 hours (as measured by the computer's system time and a real stopwatch) shows an elapsed time of 24 hours plus about 5 seconds (not milliseconds). Is this a known problem with Stopwatch? (A related question would be "am I crazy?", but you can try it for yourself.) Given its usage as a diagnostics tool, I can see where a discrepancy like this would only show up when measuring long durations, for which most people would use something other than a Stopwatch. If I'm really lucky, then both Stopwatch and audio playback are driven by the same underlying mechanism, and thus will stay in sync with each other for days on end. Any chance this is true?

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  • Should I use early returns in C#?

    - by Bobby
    I've learned Visual Basic and was always taught to keep the flow of the program without interruptions, like Goto, Exit and Return. Using nested ifs instead of one return statement seems very natural to me. Now that I'm partly migrating towards C#, I wonder what the best practice is for C-like languages. I've been working on a C# project for some time, and of course discover more code of ExampleB and it's hurting my mind somehow. But what is the best practice for this, what is more often used and are there any reasons against one of the styles? public void ExampleA() { if (a != b) { if (a != c) { bool foundIt; for (int i = 0; i < d.Count && !foundIt; i++) { if (element == f) foundIt = true; } } } } public void ExampleB() { if (a == b) return; if (a == c) return; foreach (object element in d) { if (element == f) break; } }

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  • Externally disabling signals for a Linux program.

    - by Harry
    Hello, On Linux, is it possible to somehow disable signaling for programs externally... that is, without modifying their source code? Context: I'm calling a C (and also a Java) program from within a bash script on Linux. I don't want any interruptions for my bash script, and for the other programs that the script launches (as foreground processes). While I can use a... trap '' INT ... in my bash script to disable the Ctrl C signal, this works only when the program control happens to be in the bash code. That is, if I press Ctrl C while the C program is running, the C program gets interrupted and it exits! This C program is doing some critical operation because of which I don't want it be interrupted. I don't have access to the source code of this C program, so signal handling inside the C program is out of question. #!/bin/bash trap 'echo You pressed Ctrl C' INT # A C program to emulate a real-world, long-running program, # which I don't want to be interrupted, and for which I # don't have the source code! # # File: y.c # To build: gcc -o y y.c # # #include <stdio.h> # int main(int argc, char *argv[]) { # printf("Performing a critical operation...\n"); # for(;;); // Do nothing forever. # printf("Performing a critical operation... done.\n"); # } ./y Regards, /HS

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  • Determining the health of a Cisco switch port?

    - by ewwhite
    I've been chasing a packet-loss and network stability issue for a handful of end-users on an internal network for the past few days... These issues surfaced recently, however, the location was struck by lightning six weeks ago. I was seeing 5-10% packet loss between a stack of four Cisco 2960's and several PC's and phones on the other side of a 77-meter run. The PC's were run inline with the phones over a trunked link. We were seeing dropped calls and interruptions in client-server applications and Microsoft Exchange connectivity. I tried the usual troubleshooting steps remotely, having a local technician do the following during breaks in user and production activity: change cables between the wall jack and device. change patch cables between the patch panel and switch port(s). try different switch ports within the 2960 stack. change end-user devices with known-good equipment (new phones, different PC's). clear switch port interface counters and monitor incrementing errors closely. (Pastebin output of sh int) Pored over the device logs and Observium RRD graphs. No link up/down issues from the switch side. change power strips on the end-user side. test cable runs from the Cisco 2960 using test cable-diagnostics tdr int Gi4/0/9 (clean)* test cable runs with a Tripp-Lite cable tester. (clean) run diagnostics on the switch stack members. (clean) In the end, it took three changes of switch ports to find a stable solution. The only logical conclusion is that a few Cisco 2960 switch ports are bad or flaky... Not dead, but not consistent in behavior either. I'm not used to seeing individual ports die in this manner. What else can I test or check to determine if these devices are bad? Is it common for single ports to have problems, rather than a contiguous bank of ports? BTW - show cable-diagnostics tdr int Gi4/0/14 is very cool... Interface Speed Local pair Pair length Remote pair Pair status --------- ----- ---------- ------------------ ----------- -------------------- Gi4/0/14 1000M Pair A 79 +/- 0 meters Pair B Normal Pair B 75 +/- 0 meters Pair A Normal Pair C 77 +/- 0 meters Pair D Normal Pair D 79 +/- 0 meters Pair C Normal

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  • Is my Cisco switch port bad?

    - by ewwhite
    I've been chasing a packet-loss and network stability issue for a handful of end-users on an internal network for the past few days... These issues surfaced last week, however the location was struck by lightning six weeks ago. I was seeing 5-10% packet loss between a stack of four Cisco 2960's and several PC's and phones on the other side of a 77-meter run. The PC's were run inline with the phones over a trunked link (switchport configuration pastebin). We were seeing dropped calls and interruptions in client-server applications and Microsoft Exchange connectivity. I tried the usual troubleshooting steps remotely, having a local technician do the following during breaks in user and production activity: change cables between the wall jack and device. change patch cables between the patch panel and switch port(s). try different switch ports within the 2960 stack. change end-user devices with known-good equipment (new phones, different PC's). clear switch port interface counters and monitor incrementing errors closely. (Pastebin output of sh int) Pored over the device logs and Observium RRD graphs. No link up/down issues from the switch side. change power strips on the end-user side. test cable runs from the Cisco 2960 using test cable-diagnostics tdr int Gi4/0/9 (clean)* test cable runs with a Tripp-Lite cable tester. (clean) run diagnostics on the switch stack members. (clean) In the end, it took three changes of switch ports to find a stable solution. The only logical conclusion is that a few Cisco 2960 switch ports are bad or flaky... Not dead, but not consistent in behavior either. I'm not used to seeing individual ports die in this manner. What else can I test or check to determine if these devices are bad? Is it common for single ports to have problems, rather than a contiguous bank of ports? BTW - show cable-diagnostics tdr int Gi4/0/14 is very cool... Interface Speed Local pair Pair length Remote pair Pair status --------- ----- ---------- ------------------ ----------- -------------------- Gi4/0/14 1000M Pair A 79 +/- 0 meters Pair B Normal Pair B 75 +/- 0 meters Pair A Normal Pair C 77 +/- 0 meters Pair D Normal Pair D 79 +/- 0 meters Pair C Normal

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  • Methods in Customized View did not get invoke in AppDelegate, Why?

    - by NorthKyut
    I want the methods pauseGame in customized UIView - MyGameView get invoked when the phone is locked or interrupted. So I have a pauseGame method but it can't stop the timer when user lock screen (command+L). The lock screen did appear but the game still running at the background. So I added the testPause method to MyGameView and MyGameAppDelegate and and put a breakpoint to debug it. When screen locked it, the screen lock appeared and the code did stop at the breakpoint. But when I tried to step into the testPause method, it didn't take me to the method in MyGameView (it just passed it, not skipped) and no message was printed on terminal by NSLog. Why? What did I miss? // // MyGameAppDelegate.h // MyGame // #import <UIKit/UIKit.h> @class MyGameViewController; @class MyGameView; @interface MyGameAppDelegate : NSObject { UIWindow *window; MyGameViewController *viewController; MyGameView *view; } @property (nonatomic, retain) IBOutlet UIWindow *window; @property (nonatomic, retain) IBOutlet MyGameViewController *viewController; @property (nonatomic, retain) IBOutlet MyGameView *view; @end // // MyGameAppDelegate.m // MyGame // #import "MyGameAppDelegate.h" #import "MyGameViewController.h" #import "MyGameView.h" @implementation MyGameAppDelegate @synthesize window; @synthesize viewController; @synthesize view; - (void)applicationWillResignActive:(UIApplication *)application { /* Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state. Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game. */ [view pauseGame]; [view testPause]; } @end // // MyGameView.h // MyGame @interface MyGameView : UIView { - (void)pauseGame; - (void)testPause; @end // // MyGameView.m // MyGame // #import "MyGameView.h" #import "AtlasSprite.h" #import "MyGameViewController.h" #import "SecondViewController.h" @implementation MyGameView - (void)pauseGame { [theTimer invalidate]; theTimer = nil; } - (void)testPause{ NSLog(@"TestPause"); } @end

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  • Building Enterprise Smartphone App &ndash; Part 4: Application Development Considerations

    - by Tim Murphy
    This is the final part in a series of posts based on a talk I gave recently at the Chicago Information Technology Architects Group.  Feel free to leave feedback. Application Development Considerations Now we get to the actual building of your solutions.  What are the skills and resources that will be needed in order to develop a smartphone application in the enterprise? Language Knowledge One of the first things you need to consider when you are deciding which platform language do you either have the most in house skill base or can you easily acquire.  If you already have developers who know Java or C# you may want to use either Android or Windows Phone.  You should also take into consideration the market availability of developers.  If your key developer leaves how easy is it to find a knowledgeable replacement? A second consideration when it comes to programming languages is the qualities exposed by the languages of a particular platform.  How well does that development language and its associated frameworks support things like security and access to the features of the smartphone hardware?  This will play into your overall cost of ownership if you have to create this infrastructure on your own. Manage Limited Resources Everything is limited on a smartphone: battery, memory, processing power, network bandwidth.  When developing your applications you will have to keep your footprint as small as possible in every way.  This means not running unnecessary processes in the background that will drain the battery or pulling more data over the airwaves than you have to.  You also want to keep your on device in as compact a format as possible. Mobile Design Patterns There are a number of design patterns that have either come to life because of smartphone development or have been adapted for this use.  The main pattern in the Windows Phone environment is the MVVM (Model-View-View-Model).  This is great for overall application structure and separation of concerns.  The fun part is trying to keep that separation as pure as possible.  Many of the other patterns may or may not have strict definitions, but some that you need to be concerned with are push notification, asynchronous communication and offline data storage. Real estate is limited on smartphones and even tablets. You are also limited in the type of controls that can be represented in the UI. This means rethinking how you modularize your application. Typing is also much harder to do so you want to reduce this as much as possible.  This leads to UI patterns.  While not what we would traditionally think of as design patterns the guidance each platform has for UI design is critical to the success of your application.  If user find the application difficult navigate they will not use it. Development Process Because of the differences in development tools required, test devices and certification and deployment processes your teams will need to learn new way of working together.  This will include the need to integrate service contracts of back-end systems with mobile applications.  You will also want to make sure that you present consistency across different access points to corporate data.  Your web site may have more functionality than your smartphone application, but it should have a consistent core set of functionality.  This all requires greater communication between sub-teams of your developers. Testing Process Testing of smartphone apps has a lot more to do with what happens when you lose connectivity or if the user navigates away from your application. There are a lot more opportunities for the user or the device to perform disruptive acts.  This should be your main testing concentration aside from the main business requirements.  You will need to do things like setting the phone to airplane mode and seeing what the application does in order to weed out any gaps in your handling communication interruptions. Need For Outside Experts Since this is a development area that is new to most companies the need for experts is a lot greater. Whether these are consultants, vendor representatives or just development community forums you will need to establish expert contacts. Nothing is more dangerous for your project timelines than a lack of knowledge.  Make sure you know who to call to avoid lengthy delays in your project because of knowledge gaps. Security Security has to be a major concern for enterprise applications. You aren't dealing with just someone's game standings. You are dealing with a companies intellectual property and competitive advantage. As such you need to start by limiting access to the application itself.  Once the user is in the app you need to ensure that the data is secure at all times.  This includes both local storage and across the wire.  This means if a platform doesn’t natively support encryption for these functions you will need to find alternatives to secure your data.  You also need to keep secret (encryption) keys obfuscated or locked away outside of the application. People can disassemble the code otherwise and break your encryption. Offline Capabilities As we discussed earlier one your biggest concerns is not having connectivity.  Because of this a good portion of your code may be dedicated to handling loss of connection and reconnection situations.  What do you do if you lose the network?  Back up all your transactions and store of any supporting data so that operations can continue off line. In order to support this you will need to determine the available flat file or local data base capabilities of the platform.  Any failed transactions will need to support a retry mechanism whether it is automatic or user initiated.  This also includes your services since they will need to be able to roll back partially completed transactions.  What ever you do, don’t ignore this area when you are designing your system. Deployment Each platform has different deployment capabilities. Some are more suited to enterprise situations than others. Apple's approach is probably the most mature at the moment. Prior to the current generation of smartphone platforms it would have been Windows CE. Windows Phone 7 has the limitation that the app has to be distributed through the same network as public facing applications. You mark them as private which means that they are only accessible by a direct URL. Unfortunately this does not make them undiscoverable (although it is very difficult). This will change with Windows Phone 8 where companies will be able to certify their own applications and distribute them.  Given this Windows Phone applications need to be more diligent with application access in order to keep them restricted to the company's employees. My understanding of the Android deployment schemes is that it is much less standardized then either iOS or Windows Phone. Someone would have to confirm or deny that for me though since I have not yet put the time into researching this platform further. Given my limited exposure to the iOS and Android platforms I have not been able to confirm this, but there are varying degrees of user involvement to install and keep applications updated. At one extreme the user just goes to a website to do the install and in other case they may need to download files and perform steps to install them. Future Bluetooth Today we use Bluetooth for keyboards, mice and headsets.  In the future it could be used to interrogate car computers or manufacturing systems or possibly retail machines by service techs.  This would open smartphones to greater use as a almost a Star Trek Tricorder.  You would get you all your data as well as being able to use it as a universal remote for just about any device or machine. Better corporation controlled deployment At least in the Windows Phone world the upcoming release of Windows Phone 8 will include a private certification and deployment option that is currently not available with Windows Phone 7 (Mango). We currently have to run the apps through the Marketplace certification process and use a targeted distribution method. Platform independent approaches HTML5 and JavaScript with Web Service has become a popular topic lately for not only creating flexible web site, but also creating cross platform mobile applications.  I’m not yet convinced that this lowest common denominator approach is viable in most cases, but it does have it’s place and seems to be growing.  Be sure to keep an eye on it. Summary From my perspective enterprise smartphone applications can offer a great competitive advantage to many companies.  They are not cheap to build and should be approached cautiously.  Understand the factors I have outlined in this series, do you due diligence and see if there is a portion of your business that can benefit from the mobile experience. del.icio.us Tags: Architecture,Smartphones,Windows Phone,iOS,Android

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  • The Benefits of Smart Grid Business Software

    - by Sylvie MacKenzie, PMP
    Smart Grid Background What Are Smart Grids?Smart Grids use computer hardware and software, sensors, controls, and telecommunications equipment and services to: Link customers to information that helps them manage consumption and use electricity wisely. Enable customers to respond to utility notices in ways that help minimize the duration of overloads, bottlenecks, and outages. Provide utilities with information that helps them improve performance and control costs. What Is Driving Smart Grid Development? Environmental ImpactSmart Grid development is picking up speed because of the widespread interest in reducing the negative impact that energy use has on the environment. Smart Grids use technology to drive efficiencies in transmission, distribution, and consumption. As a result, utilities can serve customers’ power needs with fewer generating plants, fewer transmission and distribution assets,and lower overall generation. With the possible exception of wind farm sprawl, landscape preservation is one obvious benefit. And because most generation today results in greenhouse gas emissions, Smart Grids reduce air pollution and the potential for global climate change.Smart Grids also more easily accommodate the technical difficulties of integrating intermittent renewable resources like wind and solar into the grid, providing further greenhouse gas reductions. CostsThe ability to defer the cost of plant and grid expansion is a major benefit to both utilities and customers. Utilities do not need to use as many internal resources for traditional infrastructure project planning and management. Large T&D infrastructure expansion costs are not passed on to customers.Smart Grids will not eliminate capital expansion, of course. Transmission corridors to connect renewable generation with customers will require major near-term expenditures. Additionally, in the future, electricity to satisfy the needs of population growth and additional applications will exceed the capacity reductions available through the Smart Grid. At that point, expansion will resume—but with greater overall T&D efficiency based on demand response, load control, and many other Smart Grid technologies and business processes. Energy efficiency is a second area of Smart Grid cost saving of particular relevance to customers. The timely and detailed information Smart Grids provide encourages customers to limit waste, adopt energy-efficient building codes and standards, and invest in energy efficient appliances. Efficiency may or may not lower customer bills because customer efficiency savings may be offset by higher costs in generation fuels or carbon taxes. It is clear, however, that bills will be lower with efficiency than without it. Utility Operations Smart Grids can serve as the central focus of utility initiatives to improve business processes. Many utilities have long “wish lists” of projects and applications they would like to fund in order to improve customer service or ease staff’s burden of repetitious work, but they have difficulty cost-justifying the changes, especially in the short term. Adding Smart Grid benefits to the cost/benefit analysis frequently tips the scales in favor of the change and can also significantly reduce payback periods.Mobile workforce applications and asset management applications work together to deploy assets and then to maintain, repair, and replace them. Many additional benefits result—for instance, increased productivity and fuel savings from better routing. Similarly, customer portals that provide customers with near-real-time information can also encourage online payments, thus lowering billing costs. Utilities can and should include these cost and service improvements in the list of Smart Grid benefits. What Is Smart Grid Business Software? Smart Grid business software gathers data from a Smart Grid and uses it improve a utility’s business processes. Smart Grid business software also helps utilities provide relevant information to customers who can then use it to reduce their own consumption and improve their environmental profiles. Smart Grid Business Software Minimizes the Impact of Peak Demand Utilities must size their assets to accommodate their highest peak demand. The higher the peak rises above base demand: The more assets a utility must build that are used only for brief periods—an inefficient use of capital. The higher the utility’s risk profile rises given the uncertainties surrounding the time needed for permitting, building, and recouping costs. The higher the costs for utilities to purchase supply, because generators can charge more for contracts and spot supply during high-demand periods. Smart Grids enable a variety of programs that reduce peak demand, including: Time-of-use pricing and critical peak pricing—programs that charge customers more when they consume electricity during peak periods. Pilot projects indicate that these programs are successful in flattening peaks, thus ensuring better use of existing T&D and generation assets. Direct load control, which lets utilities reduce or eliminate electricity flow to customer equipment (such as air conditioners). Contracts govern the terms and conditions of these turn-offs. Indirect load control, which signals customers to reduce the use of on-premises equipment for contractually agreed-on time periods. Smart Grid business software enables utilities to impose penalties on customers who do not comply with their contracts. Smart Grids also help utilities manage peaks with existing assets by enabling: Real-time asset monitoring and control. In this application, advanced sensors safely enable dynamic capacity load limits, ensuring that all grid assets can be used to their maximum capacity during peak demand periods. Real-time asset monitoring and control applications also detect the location of excessive losses and pinpoint need for mitigation and asset replacements. As a result, utilities reduce outage risk and guard against excess capacity or “over-build”. Better peak demand analysis. As a result: Distribution planners can better size equipment (e.g. transformers) to avoid over-building. Operations engineers can identify and resolve bottlenecks and other inefficiencies that may cause or exacerbate peaks. As above, the result is a reduction in the tendency to over-build. Supply managers can more closely match procurement with delivery. As a result, they can fine-tune supply portfolios, reducing the tendency to over-contract for peak supply and reducing the need to resort to spot market purchases during high peaks. Smart Grids can help lower the cost of remaining peaks by: Standardizing interconnections for new distributed resources (such as electricity storage devices). Placing the interconnections where needed to support anticipated grid congestion. Smart Grid Business Software Lowers the Cost of Field Services By processing Smart Grid data through their business software, utilities can reduce such field costs as: Vegetation management. Smart Grids can pinpoint momentary interruptions and tree-caused outages. Spatial mash-up tools leverage GIS models of tree growth for targeted vegetation management. This reduces the cost of unnecessary tree trimming. Service vehicle fuel. Many utility service calls are “false alarms.” Checking meter status before dispatching crews prevents many unnecessary “truck rolls.” Similarly, crews use far less fuel when Smart Grid sensors can pinpoint a problem and mobile workforce applications can then route them directly to it. Smart Grid Business Software Ensures Regulatory Compliance Smart Grids can ensure compliance with private contracts and with regional, national, or international requirements by: Monitoring fulfillment of contract terms. Utilities can use one-hour interval meters to ensure that interruptible (“non-core”) customers actually reduce or eliminate deliveries as required. They can use the information to levy fines against contract violators. Monitoring regulations imposed on customers, such as maximum use during specific time periods. Using accurate time-stamped event history derived from intelligent devices distributed throughout the smart grid to monitor and report reliability statistics and risk compliance. Automating business processes and activities that ensure compliance with security and reliability measures (e.g. NERC-CIP 2-9). Grid Business Software Strengthens Utilities’ Connection to Customers While Reducing Customer Service Costs During outages, Smart Grid business software can: Identify outages more quickly. Software uses sensors to pinpoint outages and nested outage locations. They also permit utilities to ensure outage resolution at every meter location. Size outages more accurately, permitting utilities to dispatch crews that have the skills needed, in appropriate numbers. Provide updates on outage location and expected duration. This information helps call centers inform customers about the timing of service restoration. Smart Grids also facilitates display of outage maps for customer and public-service use. Smart Grids can significantly reduce the cost to: Connect and disconnect customers. Meters capable of remote disconnect can virtually eliminate the costs of field crews and vehicles previously required to change service from the old to the new residents of a metered property or disconnect customers for nonpayment. Resolve reports of voltage fluctuation. Smart Grids gather and report voltage and power quality data from meters and grid sensors, enabling utilities to pinpoint reported problems or resolve them before customers complain. Detect and resolve non-technical losses (e.g. theft). Smart Grids can identify illegal attempts to reconnect meters or to use electricity in supposedly vacant premises. They can also detect theft by comparing flows through delivery assets with billed consumption. Smart Grids also facilitate outreach to customers. By monitoring and analyzing consumption over time, utilities can: Identify customers with unusually high usage and contact them before they receive a bill. They can also suggest conservation techniques that might help to limit consumption. This can head off “high bill” complaints to the contact center. Note that such “high usage” or “additional charges apply because you are out of range” notices—frequently via text messaging—are already common among mobile phone providers. Help customers identify appropriate bill payment alternatives (budget billing, prepayment, etc.). Help customers find and reduce causes of over-consumption. There’s no waiting for bills in the mail before they even understand there is a problem. Utilities benefit not just through improved customer relations but also through limiting the size of bills from customers who might struggle to pay them. Where permitted, Smart Grids can open the doors to such new utility service offerings as: Monitoring properties. Landlords reduce costs of vacant properties when utilities notify them of unexpected energy or water consumption. Utilities can perform similar services for owners of vacation properties or the adult children of aging parents. Monitoring equipment. Power-use patterns can reveal a need for equipment maintenance. Smart Grids permit utilities to alert owners or managers to a need for maintenance or replacement. Facilitating home and small-business networks. Smart Grids can provide a gateway to equipment networks that automate control or let owners access equipment remotely. They also facilitate net metering, offering some utilities a path toward involvement in small-scale solar or wind generation. Prepayment plans that do not need special meters. Smart Grid Business Software Helps Customers Control Energy Costs There is no end to the ways Smart Grids help both small and large customers control energy costs. For instance: Multi-premises customers appreciate having all meters read on the same day so that they can more easily compare consumption at various sites. Customers in competitive regions can match their consumption profile (detailed via Smart Grid data) with specific offerings from competitive suppliers. Customers seeing inexplicable consumption patterns and power quality problems may investigate further. The result can be discovery of electrical problems that can be resolved through rewiring or maintenance—before more serious fires or accidents happen. Smart Grid Business Software Facilitates Use of Renewables Generation from wind and solar resources is a popular alternative to fossil fuel generation, which emits greenhouse gases. Wind and solar generation may also increase energy security in regions that currently import fossil fuel for use in generation. Utilities face many technical issues as they attempt to integrate intermittent resource generation into traditional grids, which traditionally handle only fully dispatchable generation. Smart Grid business software helps solves many of these issues by: Detecting sudden drops in production from renewables-generated electricity (wind and solar) and automatically triggering electricity storage and smart appliance response to compensate as needed. Supporting industry-standard distributed generation interconnection processes to reduce interconnection costs and avoid adding renewable supplies to locations already subject to grid congestion. Facilitating modeling and monitoring of locally generated supply from renewables and thus helping to maximize their use. Increasing the efficiency of “net metering” (through which utilities can use electricity generated by customers) by: Providing data for analysis. Integrating the production and consumption aspects of customer accounts. During non-peak periods, such techniques enable utilities to increase the percent of renewable generation in their supply mix. During peak periods, Smart Grid business software controls circuit reconfiguration to maximize available capacity. Conclusion Utility missions are changing. Yesterday, they focused on delivery of reasonably priced energy and water. Tomorrow, their missions will expand to encompass sustainable use and environmental improvement.Smart Grids are key to helping utilities achieve this expanded mission. But they come at a relatively high price. Utilities will need to invest heavily in new hardware, software, business process development, and staff training. Customer investments in home area networks and smart appliances will be large. Learning to change the energy and water consumption habits of a lifetime could ultimately prove even more formidable tasks.Smart Grid business software can ease the cost and difficulties inherent in a needed transition to a more flexible, reliable, responsive electricity grid. Justifying its implementation, however, requires a full understanding of the benefits it brings—benefits that can ultimately help customers, utilities, communities, and the world address global issues like energy security and climate change while minimizing costs and maximizing customer convenience. This white paper is available for download here. For further information about Oracle's Primavera Solutions for Utilities, please read our Utilities e-book.

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  • My App crashes when launched on my Iphone

    - by Miky Mike
    hi guys, I have a problem here : my app crashed on my Iphone (JB) though Xcode doesn't complain about anything. The app works fine on the simulator though. However, there is this in the device logs : Thread 0 Crashed: 0 libSystem.B.dylib 0x00078ac8 kill + 8 1 libSystem.B.dylib 0x00078ab8 kill + 4 2 libSystem.B.dylib 0x00078aaa raise + 10 3 libSystem.B.dylib 0x0008d03a abort + 50 4 libstdc++.6.dylib 0x00044a20 __gnu_cxx::__verbose_terminate_handler() + 376 5 libobjc.A.dylib 0x00005958 _objc_terminate + 104 6 libstdc++.6.dylib 0x00042df2 _cxxabiv1::_terminate(void (*)()) + 46 7 libstdc++.6.dylib 0x00042e46 std::terminate() + 10 8 libstdc++.6.dylib 0x00042f16 __cxa_throw + 78 9 libobjc.A.dylib 0x00004838 objc_exception_throw + 64 10 CoreFoundation 0x0009fd0e +[NSException raise:format:arguments:] + 62 11 CoreFoundation 0x0009fd48 +[NSException raise:format:] + 28 12 Foundation 0x000125d8 -[NSURL(NSURL) initFileURLWithPath:] + 64 13 Foundation 0x000371e0 +[NSURL(NSURL) fileURLWithPath:] + 24 14 TheLearningMachine 0x00002d08 0x1000 + 7432 15 TheLearningMachine 0x00002e8c 0x1000 + 7820 16 TheLearningMachine 0x00002be4 0x1000 + 7140 17 TheLearningMachine 0x000029b6 0x1000 + 6582 18 UIKit 0x0000e47a -[UIApplication _callInitializationDelegatesForURL:payload:suspended:] + 766 19 UIKit 0x000049e0 -[UIApplication _runWithURL:payload:launchOrientation:statusBarStyle:statusBarHidden:] + 200 20 UIKit 0x0005dfd6 -[UIApplication handleEvent:withNewEvent:] + 1390 21 UIKit 0x0005d8fa -[UIApplication sendEvent:] + 38 22 UIKit 0x0005d330 _UIApplicationHandleEvent + 5104 23 GraphicsServices 0x00005044 PurpleEventCallback + 660 24 CoreFoundation 0x00034cdc __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION + 20 25 CoreFoundation 0x00034ca0 __CFRunLoopDoSource1 + 160 26 CoreFoundation 0x00027566 __CFRunLoopRun + 514 27 CoreFoundation 0x00027270 CFRunLoopRunSpecific + 224 28 CoreFoundation 0x00027178 CFRunLoopRunInMode + 52 29 UIKit 0x000040fc -[UIApplication _run] + 364 30 UIKit 0x00002128 UIApplicationMain + 664 31 TheLearningMachine 0x00002948 0x1000 + 6472 32 TheLearningMachine 0x000028fc 0x1000 + 6396 Thread 1: 0 libSystem.B.dylib 0x0002d330 kevent + 24 1 libSystem.B.dylib 0x000d6b6c _dispatch_mgr_invoke + 88 2 libSystem.B.dylib 0x000d65bc _dispatch_queue_invoke + 96 3 libSystem.B.dylib 0x000d675c _dispatch_worker_thread2 + 120 4 libSystem.B.dylib 0x0007a67a _pthread_wqthread + 258 5 libSystem.B.dylib 0x00073190 start_wqthread + 0 Thread 2: 0 libSystem.B.dylib 0x0007b19c __workq_kernreturn + 8 1 libSystem.B.dylib 0x0007a790 _pthread_wqthread + 536 2 libSystem.B.dylib 0x00073190 start_wqthread + 0 Thread 3: 0 libSystem.B.dylib 0x00000c98 mach_msg_trap + 20 1 libSystem.B.dylib 0x00002d64 mach_msg + 44 2 CoreFoundation 0x00027c38 __CFRunLoopServiceMachPort + 88 3 CoreFoundation 0x000274c2 __CFRunLoopRun + 350 4 CoreFoundation 0x00027270 CFRunLoopRunSpecific + 224 5 CoreFoundation 0x00027178 CFRunLoopRunInMode + 52 6 WebCore 0x000024e2 RunWebThread(void*) + 362 7 libSystem.B.dylib 0x0007a27e _pthread_start + 242 8 libSystem.B.dylib 0x0006f2a8 thread_start + 0 Thread 0 crashed with ARM Thread State: r0: 0x00000000 r1: 0x00000000 r2: 0x00000001 r3: 0x3e0862b4 r4: 0x00000006 r5: 0x0015a2ec r6: 0x2fffe090 r7: 0x2fffe0a0 r8: 0x3e1a378c r9: 0x00000065 r10: 0x33028e5a r11: 0x3e1ab89c ip: 0x00000025 sp: 0x2fffe0a0 lr: 0x30277abf pc: 0x30277ac8 cpsr: 0x000f0010 Any idea what the problem can be ? I've already spent my whole day on that, but... I'm stuck. Thanks in advance... Miky Mike Ok, Here is more then from the console, I get this : This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys002 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-17280-65 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… Error launching remote program: failed to get the task for process 456. Error launching remote program: failed to get the task for process 456. The program being debugged is not being run. The program being debugged is not being run. [Session started at 2010-12-23 20:33:33 +0100.] GNU gdb 6.3.50-20050815 (Apple version gdb-1472) (Thu Aug 5 05:54:10 UTC 2010) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys004 Loading program into debugger… Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-17280-72 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… Error launching remote program: failed to get the task for process 508. Error launching remote program: failed to get the task for process 508. The program being debugged is not being run. The program being debugged is not being run. And here is the code page that calls the URL import "TheLearningMachineAppDelegate.h" import "RootViewController.h" @implementation TheLearningMachineAppDelegate @synthesize window; @synthesize navigationController; pragma mark - pragma mark Application lifecycle (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { RootViewController *rootViewController = (RootViewController *)[navigationController topViewController]; rootViewController.managedObjectContext = self.managedObjectContext; [window addSubview:[navigationController view]]; [window makeKeyAndVisible]; return YES; } (void)applicationWillResignActive:(UIApplication )application { / Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state. Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game. */ } (void)applicationDidEnterBackground:(UIApplication *)application { [self saveContext]; } (void)applicationWillEnterForeground:(UIApplication )application { / Called as part of the transition from the background to the inactive state: here you can undo many of the changes made on entering the background. */ } (void)applicationDidBecomeActive:(UIApplication )application { / Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface. */ } // Method that saves the managed object context before the application terminates. (void)applicationWillTerminate:(UIApplication *)application { [self saveContext]; } (void)saveContext { NSError *error = nil; if (managedObjectContext != nil) { if ([managedObjectContext hasChanges] && ![managedObjectContext save:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); //Replace this implementation with code to handle the error appropriately. //abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button. } } } pragma mark - pragma mark Core Data stack // Returns the managed object context for the application. (NSManagedObjectContext *)managedObjectContext { if (managedObjectContext != nil) { return managedObjectContext; } NSPersistentStoreCoordinator *coordinator = [self persistentStoreCoordinator]; if (coordinator != nil) { managedObjectContext = [[NSManagedObjectContext alloc] init]; [managedObjectContext setPersistentStoreCoordinator:coordinator]; } return managedObjectContext; } // Returns the managed object model for the application. (NSManagedObjectModel *)managedObjectModel { if (managedObjectModel != nil) { return managedObjectModel; } NSString *modelPath = [[NSBundle mainBundle] pathForResource:@"TheLearningMachine" ofType:@"momd"]; NSURL *modelURL = [NSURL fileURLWithPath:modelPath]; managedObjectModel = [[NSManagedObjectModel alloc] initWithContentsOfURL:modelURL]; return managedObjectModel; } pragma mark - pragma mark Application's Documents directory // Returns the path to the application's Documents directory. - (NSString *)applicationDocumentsDirectory { return [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject]; } // Returns the persistent store coordinator for the application. - (NSPersistentStoreCoordinator *)persistentStoreCoordinator { if (persistentStoreCoordinator != nil) { return persistentStoreCoordinator; } NSURL *storeURL = [NSURL fileURLWithPath: [[self applicationDocumentsDirectory] stringByAppendingPathComponent: @"TheLearningMachine.sqlite"]]; NSError *error = nil; persistentStoreCoordinator = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel:[self managedObjectModel]]; if (![persistentStoreCoordinator addPersistentStoreWithType:NSSQLiteStoreType configuration:nil URL:storeURL options:nil error:&error]) { NSLog(@"Unresolved error %@, %@", error, [error userInfo]); abort(); } return persistentStoreCoordinator; } pragma mark - pragma mark Memory management (void)applicationDidReceiveMemoryWarning:(UIApplication )application { / Free up as much memory as possible by purging cached data objects that can be recreated (or reloaded from disk) later. */ } (void)dealloc { [managedObjectContext release]; [managedObjectModel release]; [persistentStoreCoordinator release]; [window release]; [super dealloc]; } @end

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