This article was originally published on The Conversation. The publication contributed this article to Live Science's  Expert Voices: Op-Ed & Insights. The future of lethal autonomous weapon systems (LAWS) – often referred to in the popular press as “killer robots” – remains uncertain following a week-long meeting in Geneva to discuss their legality. While the LAWS debate in Geneva was deeper and richer than previous discussions, key definitions – which are needed to word a protocol to restrict them – remain unclear and up for continued debate. And with nations like the United Kingdom openly opposed to a ban, a protocol may end up being blocked entirely, much to to the chagrin of activists. The British say existing international humanitarian law (IHL) is sufficient to regulate LAWS. While there was universal agreement among delegations that key IHL principles such as distinction, proportionality and precautions in...

Price:  $440 (plus $50 for compatible heart-rate monitor) Mobile compatibility:  iOS and Android Data transfer:  Bluetooth, USB Features:  tracks indoor and outdoor running, cycling and swimming; multisport or triathlon mode; daily activity tracking; vibration alerts; ability to create and follow custom workouts; live race tracking (i.e., send live GPS data to others); smart notifications from mobile device Design/Comfort: The FR920XT is fairly wide, but it's thin enough to slip inside your wet suit or under your running glove. Credit: © Jeremy Lips / LiveScience.com The FR920XT may not be the smallest GPS watch (in fact, it's rather bulky), but it is slim enough to slip under a wetsuit or tuck under your sleeve. And though it's large, it's very comfortable to wear when you're working out, and the device's four buttons are easy to press. The watch also has a bright backlight that makes it easy to read, even if you're underwater. User-friendliness: The FR920X...

Price:  $250 Mobile compatibility:  iOS and Android Data transfer:  Bluetooth, USB Features:  tracks indoor and outdoor running, vibration alerts Design/Comfort: The Runner Cardio has an unconventional design that makes navigating the watch easy. Credit: © Jeremy Lips / LiveScience.com The TomTom Runner Cardio has a large, brightly lit display that's easy to read while running. And unlike most watches with buttons along the outer edges, this watch has a single button located underneath the display that can be pressed up, down, left or right. While unconventional, this design makes it easy to navigate the watch during a workout. User-friendliness: Not only is the watch easy to navigate while running, but it's also easy to figure out how to work the Runner Cardio without reading any kind of instruction manual. You can upload data from the watch to your computer by plugging the device in with a USB cord, or you can upload data wirelessly to a mobile device via Bluetooth...

Price:  $150 (plus $50 for compatible heart-rate monitor) Mobile compatibility:  iOS and Android Data transfer:  Bluetooth, USB Features:  tracks indoor and outdoor walking, running and cycling; daily activity tracking; ability to create and follow custom workouts and create custom sports profiles; vibration alerts Design/Comfort: You only have to press one button on the M400 to start tracking a workout. Credit: © Jeremy Lips / LiveScience.com The Polar M400 is made from durable materials, like stainless steel and rigid plastic, that make it seem sturdy and ready for anything. But despite its brawn, the watch is comfortable to wear while working out, and the device's five buttons are easy to press, even when you're running. I like that this watch comes in solid black or white. Many of the watches I tested were brightly colored and too bold for my taste. User-friendliness: Navigating the M400 is easy, which is more than I can say for many of the GPS watches I've teste...

Our rating : 8.5/10 Price:  $250 (plus $50 for compatible heart-rate monitor) Mobile compatibility:  iOS and Android Data transfer:  Bluetooth, USB, ANT+ Features:  tracks indoor and outdoor running, walking and cycling; tracks indoor swimming and golf; smart notifications from mobile device; daily activity tracking; vibration alerts; music controls Design/Comfort: The Vivoactive combines a touchscreen with conventional buttons, which makes navigating the watch easy. Credit: © Jeremy Lips / LiveScience.com The Vivoactive has a slim design that sets it apart from other bulky, multisport GPS watches like the Suunto Ambit3 and the Polar V800. It has a modern-looking square face that is easy to read and makes the device seem more like a smartwatch than a sports watch. Like the Fitbit Surge — another fitness watch with "smart" features — the Vivoactive combines a touch screen with conventional buttons, making it easy to navigate (once you get the ...

After testing more than 20 GPS watches, we recommend the Garmin Vivoactive as the best GPS watch overall. If you want the most bang for your buck, we recommend the Polar M400, a $150 watch that tracks running, cycling and a variety of other sports. We rounded up a total of 21 watches, including devices designed specifically for runners and triathletes. We tested these products out on runs, bike rides and, when applicable, in the pool for swim workouts. Then, we evaluated each watch based on its comfort, design, accuracy, user-friendliness and the value of the information it provided. Here are our top picks: