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Yuval Yeret

EE Times - Using agile methods in medical device development - 0 views

  • FDA and other regulatory agencies fundamentally want to see that your product has safety in mind. To do so, they require complete traceability through the hardware and software. There is even a fairly new standard, IEC 62304, adopted worldwide that is wholly focused on software traceability from requirements through architecture to tests.
  • Medical devices companies are going primarily agile to respond to change and effectively manage technical complexity by collaboratively building solutions with their partners and customers to ultimately deliver what the customer wants before the competition does.
  • demo the new functionality created after each iteration to your customers, using web-based meets. Using these tools enables you to get immediate feedback from your customers throughout the project. Continuous customer feedback reduces the risk of building the wrong solution. The fact is in most cases you can’t make the release cycle more frequent since it includes giving tests to regulatory agencies. This is a tedious process that makes sure the device is safe. Doing the whole release cycle more frequently can be way too time consuming.
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  • ou could also give a version to select customers as long as it will not be directly used for care or diagnosis on current patients. The idea there is the customer gets the current iteration in house for say a blood analyzer. They could load it with real patient data and test out the new functionality as long as it is not used to diagnose an existing patient, since it has not gone through regulatory
  • agile development has gotten so popular in medical device companies that the AAMI (Association of Medical Instrumentation) is currently working on new guidance for mapping agile to a medical standard called IEC 62304.
  • In conclusion, agile development works and is being used in medical device development. The issue is you need to have a good toolchain that allows for complete traceability across the entire lifecycle in order to comply with standards. It is also very important to integrate and test frequently. This, in turn, leads to the need for build automation. With all of this in place, agile development for medical devices becomes much easier to make work.
Yuval Yeret

James Shore: The Art of Agile Development: Incremental Design and Architecture - 1 views

  • when you first create a design element—whether it's a new method, a new class, or a new architecture—be completely specific. Create a simple design that solves only the problem you face at the moment, no matter how easy it may seem to solve more general problems
  • Waiting to create abstractions will enable you to create designs that are simple and powerful.
  • The second time you work with a design element, modify the design to make it more general—but only general enough to solve the two problems it needs to solve. Next, review the design and make improvements. Simplify and clarify the code. The third time you work with a design element, generalize it further—but again, just enough to solve the three problems at hand. A small tweak to the design is usually enough. It will be pretty general at this point. Again, review the design, simplify, and clarify. Continue this pattern. By the fourth or fifth time you work with a design element—be it a method, a class, or something bigger—you'll typically find that its abstraction is perfect for your needs. Best of all, because you allowed practical needs to drive your design, it will be simple yet powerful.
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  • This is difficult! Experienced programmers think in abstractions. In fact, the ability to think in abstractions is often a sign of a good programmer. Coding for one specific scenario will seem strange, even unprofessional.
  • Continuous Design Incremental design initially creates every design element—method, class, namespace, or even architecture—to solve a specific problem. Additional customer requests guide the incremental evolution of the design. This requires continuous attention to the design, albeit at different time-scales. Methods evolve in minutes; architectures evolve over months. No matter what level of design you're looking at, the design tends to improve in bursts. Typically, you'll implement code into the existing design for several cycles, making minor changes as you go. Then something will give you an idea for a new design approach, requiring a series of refactorings to support it. [Evans] calls this a breakthrough (see Figure). Breakthroughs happen at all levels of the design, from methods to architectures.
  • Don't let design discussions turn into long, drawn-out disagreements. Follow the ten-minute rule: if you disagree on a design direction for ten minutes, try one and see how it works in practice. If you have a particularly strong disagreement, split up and try both as spike solutions. Nothing clarifies a design issue like working code.
  • Risk-Driven Architecture Architecture may seem too essential not to design up front. Some problems do seem too expensive to solve incrementally, but I've found that nearly everything is easy to change if you eliminate duplication and embrace simplicity. Common thought is that distributed processing, persistence, internationalization, security, and transaction structure are so complex that you must consider them from the start of your project. I disagree; I've dealt with all of them incrementally [Shore 2004a]. Two issues that remain difficult to change are choice of programming language and platform. I wouldn't want to make those decisions incrementally!
    • Yuval Yeret
       
      Possible exercise - Try to come up with various things that are risky to YAGNI. And then order them according to level of risk. Use the examples here to seed the list
  • Limit your efforts to improving your existing design
  • To apply risk-driven architecture, consider what it is about your design that concerns you and eliminate duplication around those concepts
  • Your power lies in your ability to chooose which refactorings to work on. Although it would be inappropriate to implement features your customers haven't asked for, you can direct your refactoring efforts towards reducing risk. Anything that improves the current design is okay—so choose improvements that also reduce future risk.
  • design is so important in XP that we do it all the time
  • Don't try to use incremental design without a commitment to continuous daily improvement (in XP terms, merciless refactoring.) This requires self-discipline and a strong desire for high-quality code from at least one team member. Because nobody can do that all the time, pair programming, collective code ownership, energized work, and slack are important support mechanisms.
  • Test-driven development is also important for incremental design. Its explicit refactoring step, repeated every few minutes, gives pairs continual opportunities to stop and make design improvements. Pair programming helps in this area, too, by making sure that half of the team's programmers—as navigators—always have an opportunity to consider design improvements.
  • Alternatives If you are uncomfortable with XP's approach to incremental design, you can hedge your bets by combining it with up-front design. Start with an up-front design stage and then commit completely to XP-style incremental design. Although it will delay the start of your first iteration (and may require some up-front requirements work, too), this approach has the advantage of providing a safety net without incurring too much risk.
Yuval Yeret

GE Healthcare Goes Agile | Dr Dobb's - 0 views

  • we operate in a highly regulated environment so there are a number of additional quality and regulatory steps that must be completed before we can accept a "user story"— that scenario written in the business language of the user that captures what he or she wants to achieve. Therefore, our "definition of done" — that is, the list of activities that add value to the product such as unit tests, code coverage, and code reviews — turned out to be lengthy.
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    "Modify: It's OK to use a hybrid approach to agile. GE Imaging Solutions needed more up-front planning and post-sprint testing, for example. "
Yuval Yeret

FDA Endorses Agile: What Does that Mean? | MDDI Medical Device and Diagnostic Industry ... - 0 views

  • The guidance covers several key topics such as documentation, evolutionary design and architecture, traceability, verification and validation, managing changes and “done” criteria. the document has become a must-have reference document for every professional implementing Agile to develop medical devices software. It focuses on providing the following:
Yuval Yeret

James Shore: The Art of Agile Development: Simple Design - 0 views

  • Simple Design AudienceProgrammers Our design is easy to modify and maintain
  • Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away. —Antoine de Saint-Exupéry Any intelligent fool can make things bigger, more complex and more violent. It takes a touch of genius and a lot of courage to move in the opposite direction. —Albert Einstein
  • When writing code, agile developers often stop to ask themselves, "What is the simplest thing that could possibly work?" They seem to be obssessed with simplicity. Rather than anticipating changes and providing extensibility hooks and plug-in points, they create a simple design that anticipates as little as possible, as cleanly as possible. Unintuitively, this results in designs that are ready for any change, anticipated or not.
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  • I don't think XP and patterns are conflicting. It's how you use patterns. The XP guys have patterns in their toolbox, it's just that they refactor to the patterns once they need the flexibility
  • You Aren't Gonna Need It (YAGNI) This pithy XP saying sums up an important aspect of simple design: avoid speculative coding. Whenever you're tempted to add something to your design, ask yourself if it supports the stories and features you're currently delivering. If not, well... you aren't gonna need it. Your design could change. Your customers' minds could change.
  • We do this because excess code makes change difficult. Speculative design, added to make specific changes easy, often turns out to be wrong in some way, which actually makes changes more difficult. It's usually easier to add to a design than to fix a design that's wrong. The incorrect design has code that depends on it, sometimes locking bad decisions in place.
  • Once and Only Once
  • avoid duplication. "Once and only once" is the Extreme Programming phrase. The authors of The Pragmatic Programmer [Hunt & Thomas] use "don't repeat yourself," or the DRY principle.
  • Self-Documenting Code Simplicity is in the eye of the beholder. It doesn't matter much if you think the design is simple; if the rest of your team or future maintainers of your software find it too complicated, then it is.
  • What if we know we're going to need a feature? Shouldn't we put in a design hook for it? In XP, the plan can change every week. Unless you're implementing the feature that very week, don't put the hook in. The plan could change, leaving you stuck with unneeded code.
  • Results When you create simple designs, you avoid adding support for any features other than the ones you're working on in the current iteration. You finish work more quickly as a result. When you use simple design well, your design supports arbitrary changes easily. Although new features might require a lot of new code, changes to existing code are localized and straightforward.
  • Simple design requires continuous improvement through refactoring and incremental design and architecture. Without it, your design will fail to evolve with your requirements. Don't use simple design as an excuse for poor design. Simplicity requires careful thought. As the Einstein quote at the beginning of this section says, it's a lot easier to create complex designs than simple ones. Don't pretend "simple" means "fastest" or "easiest.
  • Until recently, the accepted best practice in design followed the advice Erich Gamma now disavows: "The key to maximizing reuse lies in anticipating new requirements and changes to existing requirements, and in designing your systems so they can evolve accordingly."
Yuval Yeret

Scrum Breakfast: Scaling Scrum: SAFe, DAD, or LeSS? - 0 views

  • LeSS is clearly in the Scrum and Agile tradition. It is the simplest of the three approaches and makes only a few changes to vanilla Scrum. When I look at Spotify, an organization that has scaled from 6 to 1200 staff members, I see a company architecture that is very close to LeSS. It will be a very natural approach for small organizations that are scaling up as they grow.
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