> As usual, mostly western commentators sitting on their high horses pointing and pontificating with no idea of local context or understanding.
Pray tell, what context justifies arbitrary lynchings, summary executions, extrajudicial capital punishment, and an overall disrespect for human life?
Perhaps it's the view from the high horse I'm sitting on, but when I look throughout europe I don't see nations with major drug problems, and they haven't fixed any problems they had with assassinations.
Could you please provide any insight on what makes this sort of rampant uncivilized behaviour necessary or even remotely justified?
> But hyperloop? Nothing new really needs to be discovered.
This isn't true.
The concept of a moving load travelling over the rayleigh wave speed on heterogeneous soils is something that's very new, very problematic, and very expensive to deal with.
Let's put it this way: the french currently hold the conventional high-speed railway speed record for just bellow 600km/h, and yet they are only able to operate their TGV trains on the record-breaking track at 320km/h. They can't push it any faster due to all the maintenance problems caused by very high speed travel, although SNCF is one of the leading rail companies and the track is brand new.
If there were no technical issues to be resolved, they wouldn't be capping their circulation speeds at around half their speed record.
This is one of the many technical issues. But then there are the multitude of economic problems which hyperloop is entirely unable to offer any solution, yet alone make a case.
Strapping a rocket on a short stretch of track is not a technical solution. It's just a marketing trick.
Oh I certainly didn't mean for my comment to come off as they have nothing new to do only that all of those issues, as far as I can tell, are engineering issues where yes they'll have to come up with new stuff but that what they want to accomplish is perfectly within the realm of discovered physics, etc.
So I just wanted to say it's an engineering issue at this point. But as far as I can tell that's still true maybe I just didn't convey that very well initially though I'm certainly not an expert at this so I concede I could certainly be wrong as well.
Perhaps my comment doesn't add as much to the conversation as I thought it would. Oh well.
> So I just wanted to say it's an engineering issue at this point.
It's far more than a mere engineering issue. It's primarily an economic issue. The engineering issues are mitigated by throwing cash at them, but in the end for an infrastructure project to make sense the payoff must be greater than the investment.
Meanwhile, air travel is already cheaper than conventional high-speed rail, is far more flexible to manage, and operates on a cruise speed that is at least equivalent to the best case scenario sold by hyperloop's salespeople.
Any airline is able to transport hundreds of people at a cruise speed between 800 and 900km/h with an investment of around 200 million dollars. Hyperloop's salespeople are selling a concept whose cost is some orders of magnitude higher, takes longer to build, and competes with ticket prices that are somewhere between 100 and 200 dollars a ticket. While an airline needs to rely on those 100 dollar tickets to pay off their 200 million dollar investment, how do hyperloop's salesteam expect an operator to amortize a trillion-dollar investment by competing in a market based on those ticket prices?
Furthermore, essentially airlines only need to maintain their planes and pay airport costs. An hyperloop operator needs to maintain, in addition to the vehicle, hundeds of kilometer of experimental track sections. Where's the business case?
There's a good reason why hyperloop's salesteam only invest in marketing and propaganda, and in spite of being backed by a savvy scifi-inclined billionaire with a long history of investing in amazing projects we don't see him opening his wallet to fund a real-world project. Instead, the project is focused on convincing others to foot the bill.
> A successful tube transport system could be technologically ground breaking. Theoretically they'd be faster than airplanes and use a fraction of the fuel/energy (once they're constructed of course; not counting development costs).
The track would also be far more expensive to operate and build than high-speed rail in pretty much any aspect of the project, the tolerances that need to be complied with for safety reasons are orders of magnitude smaller than the ones in high-speed rail, and it's impossible to ensure a human-tolerable ride.
It appears that everyone is caught in the romantic vision of the future that the Hyperloop salespeople are dedicated to sell to the public, but rarely are the fundamental problems even mentioned.
There are plenty of good reasons why maglev hasn't caught, and the concept being sold by Hyperloop's sales team is far more limiting and expensive to pull than the maglev concept.
> The thing about hyperloop is that none of the technology is new...or even recent!
...or even works.
It's quite clear that all this hyperloop hype is a publicity scam targeted at states with deep pockets and whose governments are gagging for some propaganda talking point. The people behind hyperloop dedicate themselves to one thing only: generate hype around the project and jump from publicity stunt to publicity stunt.
The end goal is to get a government to shelve a wheelbarrow full of hard cash for them to waste the money building a prototype for propaganda purposes.
I agree that the hyperloop itself is a white elephant designed to attract investment. However, Elon Musk may be trying to use the hyperloop to obtain the funds for r&d on a space launch loop.
Capacity is a problem, but not a significant one. The problem is the cost to build, maintain and operate the infrastructure required to comply with the speed requirements, the fact that most of the technology doesn't exist, that the physics issues of a vehicle interacting with a foundation medium at very high speeds are far from being tackled (commonly referred to as trans-rayleigh trains), and that even the most basic issues of the propaganda talking points are yet to be tackled by the project.
Hyperloop reminds me of the Simpson's monorail episode in many ways.
> It seems like you are much smarter than the rest of us.
I'm not smarter than the rest of us. I just happen to be a researcher in the field of railway engineering, specifically in the design of high and very high speed tracks for conventional high-speed rail.
> Would you please tell us plebs what the fatal flaw is?
The main issue with very high speed rail is the cost required to build and maintain infrastructure that must meet such precise tolerances to keep the transportation system safe and reliable and the track usable for human transportation. Technology is still far away from providing a solution for speeds below 400km/h, and the solutions that are currently available are simply cost-prohibitive.
The problems associated with this project are further compounded by the uncertainty of the whole vehicle solution.
Then there are the physics problem. Just for a brief glimpse on the true nature of the problem, in moderately stiff soils a vehicle traveling above 700km/h triggers a response from the soil that is much like the sonic boom triggered by supersonic planes, but with Raileigh waves. This phenomena is already a major problem in some railway lines operating at lower speeds (in Sweden, for example, where a high-speed track crosses an unusually soft soil), and manifests itself in vibrations that are measured in centimeters. Currently, the only available solution to this problem is essentially reducing the traveling speed on regions where the soil stiffness is low. Yet, in hyperloop's case these issues aren't rare: they are the norm.
Adding to the problem, speeds above 700km/h mean that the vehicle clears a span of around 200m in 1 second, which means that even with the vehicle's load the entire section must have an elevation delta in the milimeter range just to limit the vertical acceleration alone. This level of precision is unheard of in civil and railway engineering, and is something that is very expensive to pull off. Now, consider this issue while adding to the mix issues such as natural changes in the region's relief. These levels of precision require a straighter line with lower inclinations, accompanied with larger turn radii. This means bridges and tunnels for hundreds (if not thousands) of kilometers.
Meanwhile, even high-speed railway has serious feasibility problems, to the point where only a hand-full of high-speed railway lines manage to turn a profit ( Paris-Lion for example).
Meanwhile, in the real world the hyperloop hype competes with air travel, which doesn't require trillion-dollar infrastructure construction and maintenance costs, is very flexible, and is far cheaper to operate.
The investment in high-speed railway lines for travel speeds between 300 and 350km/h only rarely makes sense. That's the main reason why today only a few operators have spent money on that sort of infrastructure, and the vast majority of those operators did only so for political and propaganda reasons. Increasing the infrastructure bill a few orders of magnitude to get the exact same thing that are offered today by conventional rail and air travel is simply unheard of.
> (...) but the heart of the matter in the Dallas case is whether the suspect posed an imminent threat which could not be addressed any other way besides lethal force.
At that time, the assailant already stated his purpose of killing as many police officers he could, and during his rampage he already had killed 5 police officers and gunned down dozen or so victims.
The assailant planned for this sort of attack for some time, he purposely took military training in private weekend warrior schools specifically to conduct the attack he was planning, and he even planned and mobilized himself to use explosives.
The assailant's plans were all suicide missions, and their goal was to inflict the most damage possible.
I'm not an american, and I live in a country where there isn't a single police-involved death for years, and even I am well aware that going with such a radical option was quite obviously the only way the police could ensure that the assailant would cease to be a threat to the public.
None of your points fully address what's needed to justify lethal force.
The Police Executive Research Forum emphasizes that the police are not authorized to start executing someone who was engaged in active, suicidal shooting once that person is contained:
> Many [police department] policies note that Active Shooter protocols should not be used as a response to “barricaded gunman” situations. And some policies note that active shooter incidents are dynamic, and that an incident may go in and out of active shooter status in ways that could alter the police response. For example, a situation may begin as an active shooter incident, but if the shooter barricades himself in a room where he no longer has access to potential victims, and the police can secure that room and contain the shooter, the police response should shift accordingly.
The police had him trapped for two hours before they blew him up. Perhaps there really was a new development that forced them to take action, but it's not a call we can make merely knowing how bad the guys was. It depend on the details of the situation.
My guess is that Venezuela was a theme during the elections because Maduro's regime has been caught bankrolling Podemos, the anti-establishment socialist party that managed to become the second most-voted party in the last two elections.
This statement was succesively dismissed as fake in five occasions by several judges that couldn't find any proof of this. If we trust in what some spanish newspapers said, Podemos was bankrolled by Venezuela, Iran, Venezuela, Bin Laden, Venezuela, North Korea, Fidel Castro, Russia, Venezuela, Spectre and Ronald McDonald.
> Oh, come on. Such activities happen the world and history over regardless of the ostensible public political veneer.
Socialist/communist regimes are founded on a system devised to take away any and all wealth away from the people to handle it to the state, supposedly with the objective of spreading the wealth and taking care of everyone's needs.
In practice, the system takes away any and all wealth from the people, and handles it to the regime's cronies for them to use to pamper themselves as they wish.
The history of socialism repeats itself over and over again. We see it right now in Venezuela, we saw it in Brazil with the successive Worker Party's, we see it right now in Angola as well.
> Virtual inheritance means you have a diamond pattern and haven't separated your components properly.
I've seen this argument pop out time and again as if it was a mantra of sorts, and more often than not it comes from someone with a background almost exclusively founded on Java.
Their line of reasoning essentially boils down to "Java doesn't support it, the people behind Java said something about it, therefore it's bad".
But C++ isn't Java, nor does Java dictate what is correct or what makes sense.
Particularly when the only assertion you could come up with to criticize multiple inheritance was a comment that had nothing to do with C++ or even OO programming, but only to do with your personal taste regarding your superficial impressions regarding software design.
Ooo, that Java remark burns. I've only touched Java seriously in the last few years of my career, I'm a hardcore C++/native type.
Here's the issues I take with virtual inheritance:
1. It complicates the vtable and function/member calls leading to another level of indirection, so from a performance perspective it's a negative mark.
2. The more fundamental problem is that you've botched the hasA vs isA association. If you have two classes that share a base class then that base class should be refactored into a component that can then be used as a member without polluting the class hierarchy. This leads to better composability since you can now pass this object around without pulling a whole class hierarchy with it.
You're welcome to use virtual inheritance all you want in your projects but much like knowing what subset of C++ to use(and what not) you'll never see it in code I work on.
In many senses, C++ inheritance is just shorthand for composition. That's why things like private inheritance are useful. Through this lens, virtual inheritance is automatic composition in which multiple composed objects each have a pointer to some shared object (the virtual base). It doesn't mess with hasA vs. isA at all.
> knowing what subset of C++ to use
This idea that a good coding standard necessarily bans parts of C++ has done massive damage to the C++ community. The correct subset of C++ to use is C++. Turning off parts of the language is just a cheap way to look sagacious while infantilizing developers. Every feature has its place.
I think we're just going to have to agree to disagree here.
There's a been a fair number of projects I've worked on where exceptions and RTTI introduced too much memory/perf overhead so we explicitly didn't use them. I don't feel like we were worse off for not having them.
I prefer not to work on projects that ban exceptions and RTTI. These features (especially exceptions) are important parts of the language, and without them, you can't reliably use most of the standard library (see bad_alloc) and can't really deliver value semantics, since you need awful hacks like two-phase initialization to communicate failure.
C++-without-exceptions is a very different and much worse language.
> If you're interested in limiting your market, there's a whole embedded and high performance space where this is critical.
Well, it's a preference, not a hard requirement. I'll hold my nose and work on such a codebase if there are other reasons, like the project itself being very interesting.
> Considering LLVM takes the same stance
IMHO, that's a mistake. But LLVM is an example of a project that's compelling enough to work on despite what I consider a set of poor language choices.
Pray tell, what context justifies arbitrary lynchings, summary executions, extrajudicial capital punishment, and an overall disrespect for human life?
Perhaps it's the view from the high horse I'm sitting on, but when I look throughout europe I don't see nations with major drug problems, and they haven't fixed any problems they had with assassinations.
Could you please provide any insight on what makes this sort of rampant uncivilized behaviour necessary or even remotely justified?