text:
# Daemon sets

## Introduction

• We want to scale rng in a way that is different from how we scaled worker

• We want one (and exactly one) instance of rng per node

• What if we just scale up deploy/rng to the number of nodes?

• nothing guarantees that the rng containers will be distributed evenly

• if we add nodes later, they will not automatically run a copy of rng

• if we remove (or reboot) a node, one rng container will restart elsewhere

• Instead of a deployment, we will use a daemonset

## Daemon sets in practice

• Daemon sets are great for cluster-wide, per-node processes:

• kube-proxy

• weave (our overlay network)

• monitoring agents

• hardware management tools (e.g. SCSI/FC HBA agents)

• etc.

• They can also be restricted to run only on some nodes

## Creating a daemon set

• Unfortunately, as of Kubernetes 1.14, the CLI cannot create daemon sets
• More precisely: it doesn't have a subcommand to create a daemon set
• But any kind of resource can always be created by providing a YAML description:

kubectl apply -f foo.yaml

• How do we create the YAML file for our daemon set?

• option 1: read the docs

• option 2: vi our way out of it

## Creating the YAML file for our daemon set

• Let's start with the YAML file for the current rng resource

### Exercise

• Dump the rng resource in YAML:

kubectl get deploy/rng -o yaml --export >rng.yml

• Edit rng.yml

Note: --export will remove "cluster-specific" information, i.e.:

• namespace (so that the resource is not tied to a specific namespace)
• status and creation timestamp (useless when creating a new resource)
• resourceVersion and uid (these would cause... interesting problems)

## "Casting" a resource to another

• What if we just changed the kind field?

(It can't be that easy, right?)

### Exercise

• Change kind: Deployment to kind: DaemonSet
• Save, quit

• Try to create our new resource:

kubectl apply -f rng.yml

We all knew this couldn't be that easy, right!

## Understanding the problem

• The core of the error is:

error validating data:
[ValidationError(DaemonSet.spec):
unknown field "replicas" in io.k8s.api.extensions.v1beta1.DaemonSetSpec,
...

• Obviously, it doesn't make sense to specify a number of replicas for a daemon set

• Workaround: fix the YAML

• remove the replicas field
• remove the strategy field (which defines the rollout mechanism for a deployment)
• remove the progressDeadlineSeconds field (also used by the rollout mechanism)
• remove the status: {} line at the end
• Or, we could also ...

## Use the --force, Luke

• We could also tell Kubernetes to ignore these errors and try anyway

• The --force flag's actual name is --validate=false

### Exercise

• Try to load our YAML file and ignore errors:

kubectl apply -f rng.yml --validate=false

🎩✨🐇

Wait ... Now, can it be that easy?

## Checking what we've done

• Did we transform our deployment into a daemonset?

### Exercise

• Look at the resources that we have now:

kubectl get all

We have two resources called rng:

• the deployment that was existing before

• the daemon set that we just created

We also have one too many pods.
(The pod corresponding to the deployment still exists.)

## deploy/rng and ds/rng

• You can have different resource types with the same name

(i.e. a deployment and a daemon set both named rng)

• We still have the old rng deployment

NAME                       DESIRED   CURRENT   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/rng        1         1         1            1           18m

• But now we have the new rng daemon set as well
NAME                DESIRED  CURRENT  READY  UP-TO-DATE  AVAILABLE  NODE SELECTOR  AGE
daemonset.apps/rng  2        2        2      2           2          <none>         9s

## Too many pods

• If we check with kubectl get pods, we see:

• one pod for the deployment (named rng-xxxxxxxxxx-yyyyy)

• one pod per node for the daemon set (named rng-zzzzz)

  NAME                        READY     STATUS    RESTARTS   AGE
rng-54f57d4d49-7pt82        1/1       Running   0          11m
rng-b85tm                   1/1       Running   0          25s
rng-hfbrr                   1/1       Running   0          25s
[...]

The daemon set created one pod per node, except on the master node.

The master node has taints preventing pods from running there.

(To schedule a pod on this node anyway, the pod will require appropriate tolerations.)

(Off by one? We don't run these pods on the node hosting the control plane.)

## Is this working?

• Look at the web UI

• The graph should now go above 10 hashes per second!

• It looks like the newly created pods are serving traffic correctly

• How and why did this happen?

(We didn't do anything special to add them to the rng service load balancer!)

# Labels and selectors

• The rng service is load balancing requests to a set of pods

• That set of pods is defined by the selector of the rng service

### Exercise

• Check the selector in the rng service definition:

kubectl describe service rng

• The selector is app=rng

• It means "all the pods having the label app=rng"

(They can have additional labels as well, that's OK!)

## Selector evaluation

• We can use selectors with many kubectl commands

• For instance, with kubectl get, kubectl logs, kubectl delete ... and more

### Exercise

• Get the list of pods matching selector app=rng:

kubectl get pods -l app=rng
kubectl get pods --selector app=rng

But ... why do these pods (in particular, the new ones) have this app=rng label?

## Where do labels come from?

• When we create a deployment with kubectl create deployment rng,
this deployment gets the label app=rng

• The replica sets created by this deployment also get the label app=rng

• The pods created by these replica sets also get the label app=rng

• When we created the daemon set from the deployment, we re-used the same spec

• Therefore, the pods created by the daemon set get the same labels

Note: when we use kubectl run stuff, the label is run=stuff instead.

• We would like to remove a pod from the load balancer

• What would happen if we removed that pod, with kubectl delete pod ...?

It would be re-created immediately (by the replica set or the daemon set)

• What would happen if we removed the app=rng label from that pod?

It would also be re-created immediately

Why?!?

## Selectors for replica sets and daemon sets

• The "mission" of a replica set is:

"Make sure that there is the right number of pods matching this spec!"

• The "mission" of a daemon set is:

"Make sure that there is a pod matching this spec on each node!"

• In fact, replica sets and daemon sets do not check pod specifications

• They merely have a selector, and they look for pods matching that selector

• Yes, we can fool them by manually creating pods with the "right" labels

• Bottom line: if we remove our app=rng label ...

... The pod "diseappears" for its parent, which re-creates another pod to replace it

## Isolation of replica sets and daemon sets

• Since both the rng daemon set and the rng replica set use app=rng ...

... Why don't they "find" each other's pods?

• Replica sets have a more specific selector, visible with kubectl describe

(It looks like app=rng,pod-template-hash=abcd1234)

• Daemon sets also have a more specific selector, but it's invisible

(It looks like app=rng,controller-revision-hash=abcd1234)

• As a result, each controller only "sees" the pods it manages

## Removing a pod from the load balancer

• Currently, the rng service is defined by the app=rng selector

• The only way to remove a pod is to remove or change the app label

• ... But that will cause another pod to be created instead!

• What's the solution?

• We need to change the selector of the rng service!

• Let's add another label to that selector (e.g. enabled=yes)

## Complex selectors

• If a selector specifies multiple labels, they are understood as a logical AND

(In other words: the pods must match all the labels)

• Kubernetes has support for advanced, set-based selectors

(But these cannot be used with services, at least not yet!)

## The plan

1. Add the label enabled=yes to all our rng pods

2. Update the selector for the rng service to also include enabled=yes

3. Toggle traffic to a pod by manually adding/removing the enabled label

4. Profit!

Note: if we swap steps 1 and 2, it will cause a short service disruption, because there will be a period of time during which the service selector won't match any pod. During that time, requests to the service will time out. By doing things in the order above, we guarantee that there won't be any interruption.

• We want to add the label enabled=yes to all pods that have app=rng

• We could edit each pod one by one with kubectl edit ...

• ... Or we could use kubectl label to label them all

• kubectl label can use selectors itself

### Exercise

• Add enabled=yes to all pods that have app=rng:

kubectl label pods -l app=rng enabled=yes

## Updating the service selector

• We need to edit the service specification

• Reminder: in the service definition, we will see app: rng in two places

• the label of the service itself (we don't need to touch that one)

• the selector of the service (that's the one we want to change)

### Exercise

• Update the service to add enabled: yes to its selector:

kubectl edit service rng

... And then we get the weirdest error ever. Why?

## When the YAML parser is being too smart

• YAML parsers try to help us:

• xyz is the string "xyz"

• 42 is the integer 42

• yes is the boolean value true

• If we want the string "42" or the string "yes", we have to quote them

• So we have to use enabled: "yes"

For a good laugh: if we had used "ja", "oui", "si" ... as the value, it would have worked!

## Updating the service selector, take 2

### Exercise

• Update the service to add enabled: "yes" to its selector:

kubectl edit service rng

This time it should work!

If we did everything correctly, the web UI shouldn't show any change.

## Updating labels

• We want to disable the pod that was created by the deployment

• All we have to do, is remove the enabled label from that pod

• To identify that pod, we can use its name

• ... Or rely on the fact that it's the only one with a pod-template-hash label

• Good to know:

• kubectl label ... foo= doesn't remove a label (it sets it to an empty string)

• to remove label foo, use kubectl label ... foo-

• to change an existing label, we would need to add --overwrite

## Removing a pod from the load balancer

### Exercise

• In one window, check the logs of that pod:

POD=$(kubectl get pod -l app=rng,pod-template-hash -o name) kubectl logs --tail 1 --follow$POD

(We should see a steady stream of HTTP logs)

• In another window, remove the label from the pod:

kubectl label pod -l app=rng,pod-template-hash enabled-

(The stream of HTTP logs should stop immediately)

There might be a slight change in the web UI (since we removed a bit of capacity from the rng service). If we remove more pods, the effect should be more visible.

## Updating the daemon set

• If we scale up our cluster by adding new nodes, the daemon set will create more pods

• These pods won't have the enabled=yes label

• If we want these pods to have that label, we need to edit the daemon set spec

• We can do that with e.g. kubectl edit daemonset rng

## We've put resources in your resources

• Reminder: a daemon set is a resource that creates more resources!

• There is a difference between:

• the label(s) of a resource (in the metadata block in the beginning)

• the selector of a resource (in the spec block)

• the label(s) of the resource(s) created by the first resource (in the template block)

• We would need to update the selector and the template

• The template must match the selector

(i.e. the resource will refuse to create resources that it will not select)

## Labels and debugging

• When a pod is misbehaving, we can delete it: another one will be recreated

• But we can also change its labels

• It will be removed from the load balancer (it won't receive traffic anymore)

• Another pod will be recreated immediately

• But the problematic pod is still here, and we can inspect and debug it

• We can even re-add it to the rotation if necessary

(Very useful to troubleshoot intermittent and elusive bugs)

## Labels and advanced rollout control

• Conversely, we can add pods matching a service's selector

• These pods will then receive requests and serve traffic

• Examples:

• one-shot pod with all debug flags enabled, to collect logs

• pods created automatically, but added to rotation in a second step
(by setting their label accordingly)

• This gives us building blocks for canary and blue/green deployments


text:
## Precalculus (6th Edition) Blitzer

The exact value of the provided expression is $\frac{4}{5}$.
Let us assume $\theta ={{\tan }^{-1}}\left( \frac{3}{4} \right)$. Then, $\tan \theta =\frac{3}{4}$ As we know that $\tan \theta$ is positive, $\theta$ lies in the first quadrant. Now, by using the Pythagorean theorem: \begin{align} & {{r}^{2}}={{x}^{2}}+{{y}^{2}} \\ & {{r}^{2}}={{4}^{2}}+{{3}^{2}} \\ & r=\sqrt{16+9} \\ & r=5 \end{align} Then, the value of the given expression is \begin{align} & \cos \left[ {{\tan }^{-1}}\frac{3}{4} \right]=\cos \theta \\ & =\frac{x}{r} \\ & =\frac{4}{5} \end{align}

format: plain


text:
Advertisement Remove all ads

# You Have Three Resistors of Values 2ω, 3ω and 5ω. How Will You Join Them So that the Total Resistance is More than 7ω? - Physics

You have three resistors of values 2Ω, 3Ω and 5Ω. How will you join them so that the total resistance is more than 7Ω?

1) Draw a diagram for the arrangement

2) Calculate the equivalent resistance.

Advertisement Remove all ads

#### Solution

To get total resistance more than 7Ω. We can connect 2Ω,3Ω and 5Ω in series.

1)

2)

R_"equivalent" = 2 + 3 + 5 = 10Ω

Concept: Concepts of Pd (V), Current (I), Resistance (R) and Charge (Q).
Is there an error in this question or solution?
Advertisement Remove all ads

#### APPEARS IN

Advertisement Remove all ads
Advertisement Remove all ads
Share
Notifications

View all notifications

Forgot password?
Course


text:
## Mixed Outlook for Mainstream Consumer Adoption of PHEVs

##### 14 February 2009
 Bubble chart of plausible mainstream PHEV buyers’ battery requirements (light and dark gray circles) and experts’s requirements overlaid on a Ragone plot of NiMH and Li-ion batteries. Source: Ken Kurani. Click to enlarge.

A series of presentations at the SAE 2009 Hybrid Vehicle Technology Symposium held in San Diego (11-12 February) sketched a mixed outlook for mainstream consumer—i.e., not enthusiast or pioneer—adoption of coming plug-in hybrid electric vehicles (PHEVs), given current market conditions and consumer awareness and attitudes.

The findings from the studies suggest that manufacturers will need to be careful in balancing the design of all-electric range capability against a number of other factors; that competition from alternative solutions will be stiff; and that mainstream consumers still do not place the highest values on fuel economy or low emissions when purchasing a new car.

Dr. Ken Kurani from the UC Davis Institute of Transportation Studies (ITS) presented results from the latest in a series of electric drive consumer studies seeking to learn from consumers whether or not PHEVs are a good idea.

 “Consumers right now, given the opportunity to manipulate the idea of a plug-in vehicle, are designing not only very different vehicles, they are designing vehicles that are much more possible than the experts are assuming.”—Ken Kurani

The ITS study worked with a national sample of households representing a plausible early market for PHEVs—households with a high potential for physically recharging—and enrolled them in a design game.

Among the study’s findings was that the majority of participating households designed a PHEV with much lower all-electric capabilities—and hence battery requirements—than automakers or experts are working with. Based on the game results, battery pack requirements would be equal to or less than 2 kWh.

New car buyers are not like pioneers, advocates and experts, Kurani noted. The Most Plausible Early Market consumers value fuel economy. The most frequent designs resulting from the game include higher charge-sustaining (CS) and charge-depleting (CD) blended operation—few valued all-electric range. All-electric driving may not be a bad idea for consumers, Kurani noted, it is just one that they don’t yet value or understand.

Questions for the industry, Kurani said, include how do we get from where households currently are to where PHEVs provide the most benefit? How to provide households with an opportunity to create value for electric driving? Which cars should be built when? And which should have incentives and when?

A trajectory through time of PHEV designs allows good things to happen. It allows us to start with batteries within lithium. It allows supplier and manufacturer cost reduction through multiple product generation. It allows more consumers to buy some electric driving sooner, and thus to experience and form value for electric driving.

—Ken Kurani

In a talk on gauging the competition between advanced vehicle powertrains, Steven Plotkin, staff scientist with Argonne National Laboratory’s Center for Transportation Research struck a slightly more pessimistic note in describing results of Argonne’s Multi-Pathways Transportation Futures Study.

 “What may look like an attractive technology to a society can look pretty crappy to a consumer.”—Steve Plotkin

What looks good against today’s conventional car may not look so good against tomorrow’s conventional car or tomorrow’s hybrid, Plotkin said. The competition against PHEVs in 2030 is likely to incorporate a radically downsized, boosted direct-injection engine; an automated manual or 7-8 speed automatic transmission; advanced tires with CR at 0.006 or below; a 30% weight reduction on the glider; advanced aerodynamics with CD of 0.22 or below; advanced accessories; and a mild hybrid drivetrain.

That could yield more than 50 mpg of fuel economy—or usage of less than 300 gallons per year—and still be a lot cheaper than a plug-in hybrid or a fuel cell vehicle, he noted.

 “Congress should not pick [vehicle technology] winners—policymakers have a hard time being neutral. Our history with alternative fuels has been truly awful.”—Steven Plotkin

There are large number of significant unknowns in terms of evaluating the success of future drivetrains, he said, including the future price of gasoline (“the most important thing”); what people think the future price of gasoline will be; future attitudes about climate change and energy security and what the government is willing to do about them; future technology progress; and how consumers will respond to new technologies.

We saw a horrible drop in vehicle sales last December [down] 36%. Hybrid sales 43%. A recent poll by the Pew Center found that global warming was the last...the last...of 20 concerns. A Rasmussen Reports poll show that 41% of the US public thinks Mankind is causing global warming...Are desires for more power, more luxury, more size reaching saturation? Recent trends say no. Research shows that people value loss of dollars a lot higher than value gained, about 1.5 times as much. People are more worried about losing than they are happy to gain...what that means is that there is a lot of uncertainty.

Given high initial costs, volatile oil prices, improving competition, an industry in poor financial shape and consumers who aren’t perfectly rational...who actually are quite risk averse...advanced technology may be a hard sell. Expect mostly incremental change unless the market is helped, or unless technology progress surprises us again.

—Steven Plotkin

Scott Miller, the CEO of research firm Synovate, also noted that while “things don’t look so good” for the auto industry right now, hybrids and plug-in hybrids are still favored by consumers against other advanced fuel-saving technologies.

 “...the first time in your entire lives you’ve ever heard the EPA and the OEMs agree on something: tax the fuel. Start talking about more than just climate change. Let’s talk about water quality, local emissions, natural resources and the wars that come from places that don’t have enough natural resources. Tax the fuel.”—Scott Miller

He also noted that their research shows that fuel efficiency is the number 12 reason for buying a car and that environmental friendliness ranked 38. Mainstream adoption by new car buyers depends on connecting with more important criteria such as reliability and durability, he said.

Consumers in the US have been spending money they don’t have, he noted. The net effect of correcting this problem will be pressure on purchase prices first and operating costs second. The industry needs to “accept the fact that the correction to the situation is that people are going to spend less, and buy less frequently.

Miller stressed that it is important to recognize that hybrids are still favored by consumers, and that is important that automakers not start behaving like they don’t believe in the future of the technology.

Resources

• Jonn Axsen and Kenneth S. Kurani (2008) The Early U.S. Market for PHEVs: Anticipating Consumer Awareness, Recharge Potential, Design Priorities and Energy Impacts (UCD-ITS-RR-08-22)

Very good and interesting article, and the conclusion is straight and clear, if US want to be serious about reducing oil addiction and CO2 emissions, one solution : Tax fuel. that's not a surprise to me at all, tax fuel works better than anything else and it is widely accepted by experts (including the CEO of Ford and Shell...). It is a deceptive and foolish illusion to believe that giving incentives to buy fuel efficient cars will make people buy them as long as the gaz price is low. You will just force automakers to build cars that consumer don't want. Automaker prefer to pay the penalty when they don't respect CAFE standard than to meet them.

Gas tax now, or keep borrowing to china to import more and more oil, the rest is BS.

Punitive action such as taxing does not work in the long-term - look at the miserable failure that is Europe - unhappy people utterly giving up on their individuality expressed through road trip culture.
As has always been the way in the past and will continue to be in the future - technological innovation bringing the life-style-related features that consumers want and will, without their knowing, save a substantial amount of emissions, reduce vehicles in landfill, and (re-)provide a vibrant economic industry, is the sole way. Is there going to be increased climate change, environmental degradation, and failing infrastructure in the short term along that path-of course. It is evil and the near-future is grim, but it is the only way to move society into the next stage. Many disparage the industrial revolution for bringing ills to society - but no society wants the undeveloped outcome of having taken the other route - despite environmentalist concerns and claims to the contrary.
People are generally idiots and the worst thing you can do is tell them so by taxing them to change their behavior. That way is retreat, conflict, and chaos - vastly unpopular and political suicide. The environmentalist dream of people behaving and caring about the long-term of either the environment or their industrial footprint or their contribution to a compact urban layout is shear nonsense - only attainable by deceiving the public with big, bright, shiny cars with cheap running costs (that don't emit, can be plugged in, and can be made part of a hub-type transport network) despite the sneers and razzing of angry (and gradually submitting) enviros.

Jer

You are absolutely wrong on the whoe thing from A to Z. What do you know about the happiness of people in europe compared to US ? nothing, I am from Europe and live in IS and can tell that you are plain wrong. The most heavilty taxed country are also the most advanced both economically an socialy :Sweeden, Islande, Norway, Denmark, Netherland, Germany, France, Belgium, Finlande. America is the model that is failing: decreasing education, need to import brains because the educational system is a complete failure, no social platform, hourly productivity is behind europe, almost no vacation time, no retirement or universal medical coverage, outrageoulsy expensive unniversities so that the access is closed for most of people, poor quality of industry in general (specialy cars), soaring societal disease like obesity, diabete, insecurity. Do you want to compare the percent of people in jail in europe and US ? faliure of the democracy (US is controlled by lobbies not by popular vote) last but not least shoking growing gap between rich and poor stagnating wages in the middle class when the 2% richest of the country are capitalizing almost one third of US wealth. Collapsing financial system (you want to beat on the value of the dollard moving forward) on the list goes on and you want to lecture the rest of the world ? do you research first you will realize are wrong you are.

Tax work and it is proven

Jer:

If I may paraphrase (and if I understand your message correctly) you are saying that the only reasonable way to move forward is to do nothing and wait for technological solutions to things for which there is no market incentive.

Or are you arguing for command-and-control style regulation (like CAFE standards), saying that they will provide the most efficient outcome. -That carmakers will eventually be able to meet the standard while still building the big bloated cars Americans like to drive?

I would argue that by taxing gas (or preferably CO2 in general) we would be creating an environment where there was incentive for such innovations. As we saw last summer, we can very quickly change the spending habits of Americans with a strong price signal, with the added benefit that the revenues from a gas tax could displace other distortionary taxes, or could fund progressive social programs and services like those the Treehugger points out are such crap here (like public education).

We already tried a gas tax of more than $2.00 per gallon. It contributed to a global collapse of our economy. Any smart economist will tell you that when prices increase, it has exactly the same effect as a tax increase with one important difference; it doesn't provide money for the government to spend. One of the most certain ways to put the whole world into a years long, major depression is to add taxes. Lucas when did america tried a$2.00 tax per gallon ?

I am amazed by the amount of lack of understanding of the way market work by some people who post here.

please forget 1 second your hate for the word "tax" and try to think a bit: america alone consume 25% of the oil produced in the world, right? Now if you put 2$gas tax per gallon you will destroy the demand in US that will weight significantly on the ovewhole demand and prevent crude oil to increase like we saw last summer. What people don't understand in this country, is that a gas tax is the best insurance against future uncontrolled oil price increase (and the dictatorship of OPEC) when the production will have hard time to meet demand as we are heading for very soon. 2nd, if you were doing your research properly on what is done in europe, where the sale tax is about 20%, you will see that it doesn't means that the price of good are 20% higher than if there were no sale tax. The market forces play here, if you increase the sales of a given amount, the market price of the goods will only increase by at worse half of the percentage of the tax increase. It is not that difficult to understand. Sales tax don't kill the economy since it is re-injected and redistributed in the economy. The failure of the american economical model is the failure to understand that the best economical system is the one that best redistribute the wealth, and the worse one is the one that concentrate the wealth as it is happening right now in US. That's what is killing america now : the ever worse redistribution of wealth, this is the recipe for the revolution and that's exactly what happened in Europe before and triggered all the revolution we have been through. What I forgot in the long list of potential failure cause of the american is : military spending. When a country is spending more than all the rest of the world together in military just to maintain its influence beyong its border the collapse of the empire is not far. First as Mr Obama, fairly mentionned it, there is no example in history of a country that can maintain its military suprematy with a decelining economy. On the contrary there is counteless example of country who sunk because there were spending more in military than in education, healtcare, infrastructure etc... All the ingredients are here for a painfull awake in america. Wake up guys with a domestic debt that is 3 times your GDP in a slowing economy you have no margin to turn the table, no margin ! Treehugger – Do you mean to imply that maintaining military supremacy will be the cause of economic decline? This is simple minded belief in what you wish was true. Like thinking people do NOT want to buy big cars. Countries that sunk because there were spending more on military than on education, healthcare, infrastructure include North Korea and Cuba and ??? Umm, were they super powers? I expect China might well surpass us in the foreseeable future. But not because of their spending on education, healthcare and social programs, but because of their totalitarian rulers and their new brand of free market. Guess what, we will be in BIG trouble when China follows their big economy with a big military. But, if we follow your philosophy, we will be slaves with clear consciences. In regard to gas taxes. We have a government to levy and collect taxes so as to provide for common defense and promote the pursuit of liberty and other essential actions. Taxation should only be used in lieu of market forces to force absolutely essential behavior that would otherwise not occur. That’s not socialism, that’s survival. Taxing/spending for things minorities (particularly Pelosi and those who pay no taxes) want is the worst form of socialism. But cheap gas begets big cars. This is too simple to argue. Oil is now$40/bl and gas is $2/gal. With today's low tax it is likely to soon be over$120/bl and $4/gal. With higher gas tax, it might become$60/bl & $4/gal. A big, big improvement and, I firmly believe, absolutely essential. Both ways$4+ /gal reduces consumption but one way works sooner and reduces imports.
This is like income taxes; they are mandatory (for some of us).
Other taxes conceivably might replace income tax, but to think voluntary contributions to the Government could, is laughable.
Nor can I imagine any way a “market” could fund the government or get the jump on these recurring oil crises by reducing our consumption NOW.

Raising gas taxes takes political guts, and aren't we overdue for at least ONE thing that is NOT business as usual. I’m not holding my breath.

Toppa Tom

You want an example of a super power that collapsed because of its military spending ? easy : URSS. And yes absolutely overmilitary spending will cause economic decline, military spending and war are intinsically inflationary, you borrow money to build equipment that don't improve the life of poeple or in the worse case destroy assets when you use them.

Asides, this idea tha China will try to outpace US in the race for military spending is just plain ridiculous, there is no evidence or even sign of this, and they simply can't afford it.

Taxes have to be used "to force absolutely essential behavior that would otherwise not occur" just like building school, providing unemployment compensation, universal healthcare, education, infrastructure, defense, etc. I agree that's not socialism that's survival, no civilized society has ever worked without taxes from the Roman empire until today, so I don't understand this hate for taxes in this country.

And yes I agree a situation with 60$crude/4$gas is way better than 120$crude/4$gas because in yje first case you control the game in the second case you are a victim.

Well yes, the USSR collapsed because of military spending. But it was OUR military spending that accomplished this.
Their communist society could not support the military spending required to keep up.
The Iraq invasion was a very huge (and unnecessary, IMHO) drain of money (it was mostly emergency discretionary and supplemental spending though, not DOD base) from the budget with essentially no "product" or domestic purchases (at least in regard to the soldiers stationed overseas).
But most of the base military budget is for nation defense as described in the constitution and most of it is spent domestically. Afghanistan is a big exception, but I think it is also not funded from the base DOD budget.
“this idea tha China will try to outpace US in the race for military spending is just plain ridiculous”
How can apparently rational people believe GM management is capable of more malicious behavior than the Chinese rulers?
Assuming you’re serious, China’s claimed expenditures are now 10 to 20 % of ours, and they’ve only just begun.
Our economy and the new admin will probably reduce military budgets but I doubt they will let it go down very much. And Iraq and Afganastan will continue to soak up $$Toppa If china wanted to play in the military race they would have started much earlier. 2nd if they have some military it is certainly not to invade US or even Japan. A country that essentially get its wealth from exporting goods don't go to war, period, sorry maybe they plan to invade Taiwan, but they don't even need to and why should we care? why should america spend so much money on their defense, what is the threat ? where are the invaders who want to penetrate US ? US is spending so much in military to do the police in the world but that is no longer affordable neither it is a good thing. Actually the US spent so much for the military during the Cold War because it had to protect the Europeans from the USSR. Had the US been smart they would have waited out WWII and then cut a deal with Germany which would probably have won. "If china wanted to play in the military race they would have started much earlier." I doubt China accepts this weird restriction. "2nd if they have some military it is certainly not to invade US or even Japan." This point would be marginally better if it pointed out how far away the US is (even in a shrinking world). It's like some little country, like Japan, attacking the US (not counting Pearl harbor). Ja voll, Mannstein. And 完全是. Umm - back to the issue. "What may look like an attractive technology to a society can look pretty crappy to a consumer.". - Steven Plotkin Does this mean, "the market will decide". And is brainwashing no longer ineffectve ? Or no longer allowed? “Congress should not pick [vehicle technology] winners—policymakers have a hard time being neutral. Our history with alternative fuels has been truly awful.” —Steven Plotkin. Guess what Plotkin, This is so obvious. But the new regeme will probably do it anyway - in spades. "New car buyers are not like pioneers, advocates and experts, Kurani noted." Are we pioneers, advocates and experts now; not geeks? Back to PHEVs. There is no way that drivers of pickups and large SUVs are going to switch to Prius-like cars. Think 'death before dishonour'. There are also low wage workers with long commutes that usually buy cars a few years old. These people can no longer get easy credit. Therefore PHEVs have neither the high mileage range nor the low price. Maybe at a pinch they might get into something like the new Opel turbo-CNG van if it was cheap enough. If this is right then GM is gonna go broke with the Volt thereby wasting billions of taxpayer's bailout money. It all seems like a slow motion crash. The Volt was never more than a headline grabber and concession to the geeks and liberal politicians to build "cars people want" (but that won't make a profit). If it outsold ALL hybrids that would be - like less than 6% of the US market? That is worth – almost nothing. Trucks have never dropped below 18% of the market. The politicians have to use our bailout money to reward the unions for their votes and the millions of$$$they donated. If I was a GM stockholder, I would be looking to "absorb" as much equity as I could and leave a note in the lobby saying "Dear Nancy Pelosi, Here, it's yours. You think you know how to run it - have fun." The Nissan Tsuru, a 1990 nissan sentra still being manufactured in Mexico sells there for around$6000.. a simplified design and economical. This is an affordable car for poor people.

Very hard to justify the cost of a hybrid based on savings, and that is what most normal people base their decisions on. You want people to afford better cars?, stimulate the economy by cutting taxes.. it always works.

Too many urban legends and bull about US debt/spending/budget is sling around.
Must read to anyone interested in real numbers and real problems:

http://www.americanthinker.com/2009/02/the_real_state_of_the_union.html

Wow. so many interesting topics in the same thread!

First, taxes are needed because the price signal is too short sighted. You can't wait for the price of oil to grow again to force people buying more efficient cars. A car is around for 10 years and replacement of the complete lot of vehicles would take a long time. We have to act on decreasing oil consumptions immediately, otherwise will find ourselves in a situation were the oil is scarce and the infrastructure and technological solutions are still not there. At that point, we will only be able to cut usage by not doing things, which would depress the economy even further.

Second, the american debt can grow pretty much indefinitely without the dollar collapsing, since the dollar is from Bretton woods the standard currency, and is also the dollar used to buy/sell oil (and since energy is the primary need of a nation, then dollars are necessary to every one).

Third, the military spendings are necessary for USA to keep control of the oil producing regions, which are vital to maintain power. No one wants to invade USA, not even URSS wanted to invade USA. It has always been (from the birth of humankind) a battle for the control of resources. This does not mean that China is not a potential trouble. They are already acting quite aggressively (although with no weapons) to control resources in Australia and Africa.

If you want to tax gas more your gona have to get rid of the income tax and bring in large consumption taxes. This is about the only way of packaging such a tax that people would welcome.

Alessio

Good post, tax is a way to anticipate the big future problem with oil

but you think that because the dollard is the standard trade currency then debt can grow indefinitely? yes and no, passed a certain limit and when other countries fele that america can no longer honor their debt, they will use other trade currency like Euro, and even Huan even if they are no officially recognized as standard trade currency. We are not that far of that point.

No US don't need to keep control of the oil producing countries, if these countries becomes politicaly unsatable, then oil price will soar and custometr will reduce their dependance to oil and these countries will be screwed so they will take care of their political stability by themselve because they have no choice.

Wintername
You are right a gas tax can be neutral, you increase tax on gaz and reduce it on income, you put taxe on emissions and reduce on incomes, then suddently the society becomes much more efficienet and pollutes less while the level of taxation hasn't changed overwhole. For non tax payers you developp public transportations, bicycle lanes,small efficient vehicles.

I agree with you that the Volt won't solve the problem any time soon if ever. But you can design cars that get 60 MPG or even better without electric hybrid tech, look at the Aptera, or altenative vehicle like the Venture Car or the Carver or the Nano or even the Honda CRX from the 80s. The Venture car is probably a pretty damn fun car to drive, and can HIT the 100MPG without really new technology. Technologies like pneumatic hybrid, stop and start without hybrid (Mazda), alternator regenerative braking (BMW) variable compression ratio (EMC-5), improved aero (Mercedes bioconcept, Aptera) and lightness (Aptera again) are not more expensive than current tech.

Its not so much about tax neutrality so much as its about giving people what they REALY want in exchange for taxing something they realy might be rather nervous about. Everyone other then tax people of course realy would like to say goodbye to income tax and property tax and all those other annoying taxes and simply go to tax as you buy consumption taxes.

@Toppa:

If you're going to write German I suggest you get it straight to be taken seriously. How about Ja wohl.

Incidentally the US hasn't won a war since the end of WWII. Some historians even question whether the US actually won that one. They base their doubts on the fact that half of Europe was enslaved by Stalin when the fighting stopped including Poland. Didn't Britain and France declare war on Germany to maintain Poland's freedom in 1939? Some victory for the West.

Very high Gas prices are necessary, but not sufficient for major PHEV adoption.

We have had high gas prices in Europe for decades, but have no PHEVs available. We have lots of small cars and diesels, but no PHEVs and no HEVs (yet).

If you consider fuel economy to be important (for whatever reason), you will need higher prices to get the cars, especially if you want PHEVs which look like being very expensive.

From a technical point of view they seem like a solution, but they are too expensive for anyone but enthusiasts and wealthy people.

As Alessio says, you can anticipate future high gas prices by adding taxes now - at leats your own government gets the money.

It is likely that gas pries will rise in the future as the world economy recovers (and this could happen very fast), but it takes several generations of cars to get the fuel economy up, so you need steady pressure, both regulatory and fuel costs to keep this happening.

The comments to this entry are closed.


text:
# Who am I??? Wait, isn't this a sudoku?

Jmw jrr qtlf tv ee M6SXr rro tr kz r tyr.

Can you find out who I am?

Hint 1:

Some parts of the puzzle have been used multiple times to guide you in the right direction.

Hint 2:

The numbers discovered by @Levieux are practically final and it does not matter which version of each will be used.

• Enigmatic is right, haha – dcfyj Jan 31 '17 at 15:44
• Well, it certainly is. :) – Maria Deleva Jan 31 '17 at 15:47
• My idea of how this might work: Its the empty sudoku, highlighted numbers might give keyword in A1Z26, cipher will give something which will give final answer – Beastly Gerbil Jan 31 '17 at 16:33
• @Techidiot: shouldn't that be a 1 then? The one in the middle is definitely a 9, though. – Levieux Jan 31 '17 at 16:58
• The M6SXr looks suspiciously like an imgur format – Beastly Gerbil Jan 31 '17 at 21:22

EDIT : wrote the complete answer.

Take a look at the grid submitted by OP.

It really looks like a sudoku ; it is a sudoku. Arrow-like symbols are 'greater than' and 'less than' symbols between adjacent numbers. Given these informations, there's an almost unique way to solve it. This part was solved by @elias.

There's also those intriguing blue squares.

which, when completed, give the digits 1,9,6 - 196 if you collapse them. 196 isn't a common number (well actually almost all numbers have some kind of special stuff, and if we find a non-special number, it will be special that it's non-special). WELL. 196 is the first potential Lychrel number - a number which cannot be formed into a palindrome by iteratively adding the reverse of itself, a process which is called the 196-algorithm. Thanks to @Levieux for this finding, and @J.R. for the 'potential' mention.

We can move on.

Using the word LYCHREL as a Vigenere key (which is advanced Cesar coding, and also a very bad way to encrypt sensitive data because of Kasiski's method for finding the length of the key) We can decode the text from OP as "You can find me at B6UVk and it is a png" . B6UVk and the mention of PNG, a picture format, guides us to a famous pic hosting website, imgurl. Using the URL prefix for SE pictures, http://i.stack.imgurl.com/codecodecode, we find the following picture. Thanks to @Levieux again.

I'm struggling with the 'spoiler' blocks.

We find this. In this picture, we have two sets of data : -CBFFIIEG 78987989 and -ACCCABAB 21547732. When associating one-to-one letters and numbers (who go A-I and 1-9 so obvously refer to a 9x9 grid... Let's say the sudoku one from the start, since OP hinted that some things should be used more than once), we form two sequences (C7-B8-... and A2-C1-...) that refer to sudoku grid numbers. That's where @Levieux stopped, and I really want to thank him again.

Here comes my original work (I feel like a fraud ^^)

I looked at the numbers of the end of his reasoning, 1994913(4/3) and 6963(4/3)853,

and the hint of OP

(who said all 4/3 versions would work).

GPS coordinates, which is coherent with the minus sign and the fact OP said numbers should be used as is. 8 digits is standard precision for GPS, so I first tried (-19.949134, -69.634853) which was coincidentally near a man-made rock giant.

Fiddling with the versions, one was right on it. So to your question "who am i ?" I say :

the Atacama Gigante.

Wanna see me ? I'm right here :

• That is indeed the right final answer. However, in order to accept one answer as the answer, it needs to have the full solution of the puzzle, including every clue described. P.S. Also, a picture of "who am I?" would be nice. :) – Maria Deleva Feb 7 '17 at 20:18
• Welcome to Puzzling, and great answer! (And yes, you can just edit in something like "Here's the solution to the Sudoku, as found by Elias"). – Deusovi Feb 7 '17 at 20:27
• Thank you. I edited the best I could, and gave credit. Any critics will be appreciated. – Lilian Delaveau Feb 7 '17 at 20:50
• @MariaDeleva I'll edit with the picture ! – Lilian Delaveau Feb 7 '17 at 21:03
• Thank you! :) I will later (not today, though) write a "The making of" post, and will explain everything (including some subtle things, that were not mentioned, but these are just details). – Maria Deleva Feb 7 '17 at 21:12

Partial solution

Interpreting it as a sudoku with relation signs between neighbouring cells, it has 8 different solutions, but the blue part is the same for all:

• I'm curious to know how you started solving that. – p.s.w.g Jan 31 '17 at 20:19
• You can start with the extreme values, I went from 1 upwards. All of the 1s have to be in a cell which is smaller than all of its neighbours. The bottom right 3x3 box only has one like this. The center right 3x3 box also. Well the top right box has few, but at that point you can use the fact that the 8th and 9th columns already have a 1, so it should be in column 7. It's quite mechanic, actually. – elias Jan 31 '17 at 20:34
• If I remember well, 1s, 2s, 9s and 8s were easy to fill, also some of the 7s. Then there was a moment were it seemed to be stuck, but some classic sudoku thoughts helped to finish the 7s. I recommend the following trick: keep tracking what is the minimal and maximal possible value of a cell. That's all what I did. – elias Jan 31 '17 at 20:44

The next part of this puzzle can be found at:

https://i.stack.imgur.com/B6UVk.png

The message translates to: "You can find me at B6UVk and it is a png".

How I got this:

Thanks to elias' solution of the sudoku we know that the blue squares form the number 196. 196 is also the first potential (not proven, as J.R. correctly commented) Lychrel number, a number which cannot be formed into a palindrome by iteratively adding the reverse of itself, a process which is called the 196-algorithm.
Now, using LYCHREL as a Vigenère key, the message "Jmw jrr qtlf tv ee M6SXr rro tr kz r tyr." translates to "You can find me at B6UVk and it is a png" (the number 6 in the image name is skipped).

So, what to do next:

The green man says: -CBFFIIEG 78987989
The red man says: -ACCCABAB 21547732

Numbers are 1-9, letters are A-I, so it's very likely these refer to squares of the sudoku, like C7-B8-F9-F8-I7-I9-E8-G9

Taking letters as columns and numbers as rows this yields 1994913(4/3) and 6963(4/3)853 for the green and red parts.
OP confirms that these digits are indeed correct, but the question remains how to interpret them. Maybe we should apply the 196 algorithm we found in the first part. Unfortunately we still have two options for both of these sequences, so let's try all four of them:
$19949134$ -> no solution within 100 iterations
$19949133$ -> solution $95288259$ found after 2 iterations
$69634853$ -> solution $1554884551$ found after 2 iterations
$69633853$ -> solution $1553553551$ found after 2 iterations
We can try to convert this to text, but it doesn't produce meaningful results.
Also, we still haven't figured out what the '-'-sign in front of the letter sequences means. Perhaps we should subtract the first digit or something like that..

Update: OP says no ciphers codes are used, so what else could we do with the numbers?
OP also indicates in a new hint that some parts of the puzzle should be used multiple times. Some new things I've tried are:
Again looking up the resulting digits in combination with the letters to find new digits, so combine 1994913(4/3) with CBFFIIEG to get C1, B9, and so on. This obviously leads to yet another set of digits. Converting these to letters (1=A, 2=B,..) doesn't give anything meaningful. Completing the same operation yet again doesn't work either.
I also tried coloring the sudoku cells based on the coordinates (both the original coordinates and the converted ones), but no letters or picture is showing up.
I tried converting the numbers based on the telephone keypad (although that may count as a cipher), but the many 9s and 1s should already have been indication that that was not going to work.
Lastly I tried several operations with the numbers 1,9,6 (using those again), like adding them to the digits we found, but no luck there either...

• nice findings! I tried it the other way around with rows and columns, and even by interpreting the minus in front of the letters as ordering them in the opposite direction. Didn't hit anything my eye in the results. – elias Feb 1 '17 at 10:04
• @Levieux how do you know its from "i.stack.imgur.com" ? – onmyway133 Feb 1 '17 at 11:26
• @onmyway133: that's the standard domain for all images uploaded on this website. – Levieux Feb 1 '17 at 11:43
• Nitpicky remark: $196$ is only the first potential Lychrel number. It's not proven. – J.R. Feb 1 '17 at 12:52
• @MariaDeleva, we seem to be stuck since the bounty was announced. Can you confirm if these digits are correct? Or at least if the idea of handling numbers and letters as row and column indices is right? – elias Feb 6 '17 at 14:10

# Wrap-up: The Making Of "Who am I??? Wait, isn't this a sudoku?"

This is not a solution to the puzzle, but provides notes from its poser. This type of answer has been approved by the community.

Caution: This post may contain spoilers.

### Inspiration

First came the Fortnightly Challenge. I then decided to look for interesting puzzles while I was thinking on a new type of puzzle (which I screwed up by doing too many mistakes in it). But while thinking on it, I found the empty "greater than" sudoku. I liked it and since I didn't see any of these here, I decided to make one of these and post it. Apparently, my fellow puzzlers liked it. So I wanted to make a new one, but this time I wanted to use it in a multi-layered puzzle and use the numbers somehow.

So the thinking process started again. What could the numbers be used for? Coordinates? Good. So I would put the coordinates hidden somehow in an imgur link. So how would you get to the imgur link? ? ? I wasn't sure.

And then one day I stumbled upon Lychrel numbers - I found them really interesting. Especially the fact that even the smallest potential Lychrel number in base 10 has not been proven as of yet and might never be proven. So I decided to use it as a key.

### Creative steps

Now I started working on the sudoku itself. I made it by hand, so at the end, where I intended to put the Lychrel number, instead of 196, I had 169. So I switched the 6s and 9s. Then, I started doing the final grid in Paint.

I wanted to have the coordinates in an image and I wanted it to be pretty (not just some text on a one-coloured background). I wanted some sticky figures with talking balloons. But since my drawing skills are really poor (see the devil here, if you do not believe me), I went looking for a suitable free to use image online. After all, I wanted it to be pretty. I found one I really liked, but since it contained 3 figures (and I needed two - for the coordinates), I had to remove one of the figures. Then I wanted to put a disclaimer saying where the image is from. But since I first found it on another site, and then I figured out the source is different, I deleted the first disclaimer and put I new one (could be seen from the traces I left in the process - I told you, my drawing skills are really poor - even the use of helping programs is not much of a help, apparently).

Then, I wanted to put the coordinates in the bubbles, but not directly. Putting A1, B2, etc., seemed too easy. So I decided - letters on the first line, numbers on the second. Since the coordinates turned out to be negatives, I put the minus sign in front of the letters as well. I was considering skipping it - making you figure out this one for yourselves, once the positive coordinates throw you in the ocean, but then I thought that might be too much of a leap and besides, the minus sign might nudge you in the right direction on what the numbers could be.

In addition, I decided that I want to hint at the directions somehow with the numbers. So, for West, I used only numbers from the first column (symbolising west) and for south - only numbers from the last row (symbolising south). But I didn't want to use the numbers from one cell only and that is why I went for column/row. Then I used the $\bbox[#f55,7px]{\color{white}{\sf{\small A}sk~{\small Q}uestion}}$ button to post the image to the stack imgur site so that I could have the link for the previous step in the puzzle.

Once I had the link, I needed to hide it somehow. I thought, I would use cipher with key (the Lychrel number). But I didn't want the cipher to be uncommon and most common ones use letters (Vigenere, for example). And since I wanted this number, specifically because it was the first potential Lychrel number, I wanted to use that - Lychrel, as the key. But if I was to encode the 8 letters only, you would never know if you got it right. So, I decided to write something. And the sentence "You can find me at" even had a double reference to the coordinates - after all, the coordinates marked a place. So I went with that. However, instead of the standard jpg, I used png, so I needed to have this as well and since I didn't want to have just .png, I wrote something dumb, but understandable.

### Logistical steps

When I decided I want to use coordinates, I wanted to find something interesting these coordinates would lead to. I didn't want to just be a random place. Also, since the sudoku contained digits 1 to 9, it had to be using these digits (i.e., no zeroes). So I looked for interesting places on Google Maps. I found the Atacama Giant (among other stuff - like triangles, circles, advertisements, swastikas and so on). And I found it amusing. Especially the fact that I can use "Who am I?". After all, "I" would be the Atacama Giant.

### Resources

• I used Paint, Gimp2, Excel, Google, Google Maps, Wikipedia, Puzzling and probably several other sites.

### Takeaway

I thought that once solving the sudoku (which takes time, more or less), the puzzle would be solved fairly quickly. But it turns out that was not the case. Perhaps, reusing certain clues (albeit, some of these were very direct: "You can find me at" obviously hints at a place, but since it also leads to an image, solvers didn't think twice of it) wasn't really the best idea and made the puzzle more difficult than I thought it would be. Also, it turned out some clues were too obscure (like using numbers for the coordinates only from a particular row/column, to hint at a geographic direction). And even posting a hint to reuse clues in the puzzle didn't seem to help much. So perhaps, I needed to put more clues in the puzzle itself - either for reassuring purposes, or for easier solving.

• Thanks for the detailed wrap-up! Oh, and I really like that devil. – elias Feb 11 '17 at 11:11
• Thanks, @MariaDeleva ! Really nice to see how you made it - I really didn't see the west-south stuff ^^ – Lilian Delaveau Feb 12 '17 at 8:25


text:
# is every point of a Berkovich space a Shilov point?

Let $k$ be an algebraically closed non-Archimedean valued field with the value group $\mathbb R$, and let $X$ be a variety over $k$. Is it true that for any point $x \in X^{an}$ of the Berkovich analytification of a variety $X$ over $k$ there exists an affinoid neighbourhood $Sp A$ of $x$ such that $x$ is the unique point in the Shilov boundary of $Sp A$ (i.e. the point on which every function $f\in A$ reaches the maximum of it's absolute value)?

(I am sorry for making probably superfluous restrictions but I am not sure what the natural/most general statement of this question is)

## 1 Answer

No. Saying that the point $x$ lies in the Shilov boundary of $\mathcal{M}(A)$ gives strong restrictions on the completed residue field $\mathscr{H}(x)$. In your case, its residue field $\widetilde{\mathscr{H}(x)}$ will be of transcendence $d$ over $\tilde{k}$, where $d$ is the dimension of the variety (see proposition 2.4.4 of Berkovich's book).

To handle the more general situation (with no assumptions on the field $k$), let me denote by $s(x)$ the previous transcendence degree and by $t(x)$ the dimension of the $\mathbb{Q}$-vector space $\sqrt{|\mathscr{H}(x)^\ast|}/\sqrt{|k^\ast|}$. Then you will find the condition $s(x)+t(x) = d$ (what is called an Abhyankar point).

If you want an explicit counter-example, pick any point of type 1 ($s+t=0$) when $d\ge 1$.

For a more interesting question, you could ask whether the result holds when you replace $X$ by the Zariski closure $Y$ of the point associated to $x$ in $X$. This is still not true, but you have to consider subtler things like points of type 4.

Let me also add that if the point is Abhyankar, then your result is true. You may find this in my paper "Les espaces de Berkovich sont angéliques" (Bulletin de la SMF 141 (2013), no. 2, 267–297).

• > This is still not true, but you have to consider subtler things like points of type 4. > if the point is Abhyankar Am I right that after restricting to the Zariski closure of $x$ and extending the scalars so that the base field is maximally complete, one may assume that $x$ is Abhyankar? – Dima Sustretov Jul 4 '14 at 10:56
• This is true only in dimension 0 and 1... Consider $\mathbb{A}^{2,an}$ with a projection $\pi$ to $\mathbb{A}^{1,an}$. Pick a point $x$ of type 2 in $\mathbb{A}^{1,an}$ and then a point $y$ of type 4 in the fiber $\pi^{-1}(x)$ (isomorphic to the line over $\mathscr{H}(x)$). This always exists if $k$ is not trivially valued. The point $y$ is not Abhyankar. It is Zariski-dense in the plane but we have $s=1$ and $t=0$. – Jérôme Poineau Jul 4 '14 at 13:50
• oh, yes, you are right of course – Dima Sustretov Jul 4 '14 at 15:05


text:
# B Non-ferrous solenoid actuator -- Force calculation

Tags:
1. Jun 2, 2017

### Anachronist

I'm trying to come up with a lightweight solenoid linear actuator, by constructing two electromagnets that telescope. The outer coil would be wrapped around a soda straw, and the inner coil would fit inside the soda straw and be wrapped around something smaller, like a bamboo skewer (which also serve as the actuator shaft).

Well, I'm wondering about the pushing or pulling force this thing can impart. The force of an electromagnet on an object would be
$$F=\frac{(N I)^2 \mu_0 A}{2 d^2}$$
where $N$ is the number of turns, $I$ is the current, $A$ is the cross-section area of the coil, and $d$ is the distance between the open end of the coil and the object.

If the object is another coil of a different diameter and windings, but with the same current, the force would be
$$F = \frac{\mu_0 I^2}{2 d^2}(N_1^2 A_1 + N_2^2 A_2)$$
This looks like it would blow up when $d=0$. And what would be the force when one coil is partially inside the other? I would think it would be less, going to zero when one coil is completely centered inside the other.

If my objective is light weight, is this even efficient, or would it be more efficient to use a strong magnet on the end of my rod?

Also, if I'm limited to, say, 0.3 amps, it seems like I'd need a lot of windings just to get 30 or so Newtons of force, and that's right at zero distance, with hardly any force seen if the actuator moves even a little bit.

2. Jun 4, 2017

### scottdave

I think you will need a Lot of turns for that size current. The following video may help you with this issue.

File size:
335.7 KB
Views:
13
3. Jun 7, 2017

### Anachronist

The current I chose is sort of arbitrary. I don't want to overload a lithium battery. But now I see that a 30C 2S 300mAh 7.4V LiPo Battery doesn't limit me to 0.3A, it limits me to 30×0.3A, or 9A as the maximum safe discharge current.

In my quest to make something lightweight, I'm wondering if a torsional actuator might be better. I noticed that the magnets inside the disposable heads of my Sonicare toothbrush are incredibly powerful bits of magnetic material, about 6×3×1.5 mm, with the north-south axis perpendicular to the 6×3 face. They weigh about 1 gram each. If I stick two of them together I have a lot of trouble pulling them apart. Maybe I could put one of those on each side of a bamboo skewer, with a coil on each side, and attach the skewer to a pushrod horn.

4. Jun 8, 2017

### Anachronist

I just realized that the quantity $NI$ in the formula above is a constant for a given wire diameter, because wire has some resistance. 40 gauge copper wire has a resistance of about 3.5 ohms/m. Given a constant voltage source, the higher the value of $N$, the higher the resistance, which decreases the current $I$ proportionally. When I rewrite the force equation in terms of voltage and wire length, a bunch of stuff cancels out and I'm left with
$$F=\frac{V^2 \mu_0}{8\pi\Omega^2 d^2}$$
where $\Omega$ in this case is the resistance per unit length.

This means that for a given input voltage $V$ and distance to object $d$, the force is determined completely by $\Omega$. The number of turns and the diameter of the coil are irrelevant!

The only reason to have a large number of turns would be to reduce the current to preserve the battery.

For a 7.4V battery, a 40 gauge wire coil at 3.5 ohms/m, at 1mm from an object, would exert a force of 0.24 N regardless of the number of turns. I need more force, so it looks like 40 gauge wire won't work at all.

If I want a coil that exerts 3N of force (about 2/3 lb) I need to go to a heavier gauge magnet wire. 31 gauge, at 0.43 ohms/m, would give me 3.3N. Then if I wanted to limit the current to 9 amps, I'd need about 2 meters of wire, weighing 3.6 g.

I may be able to increase the force and lighten the weight if I used the Sonicare toothbrush magnets I mentioned earlier.

Last edited: Jun 8, 2017


text:
## Encyclopedia > 2070s

Article Content

# 2070s

Centuries: 20th century - 21st century - 22nd century

Decades: 2020s 2030s 2040s 2050s 2060s - 2070s - 2080s 2090s 2100s 2110s 2120s

Events and Trends

All Wikipedia text is available under the terms of the GNU Free Documentation License

Search Encyclopedia
 Search over one million articles, find something about almost anything!

Featured Article
 Maxwells equations ... Ithrough A = ∫AJ·dA). Note: unless there is a capacitor or some other place where $\nabla \cdot \mathbf{J} \ne 0$, the second term ...


text:
## Precalculus (10th Edition)

We are given the parametric equations: $\begin{cases} x=4\sin t-2\sin (2t)\\ y=4\cos t-2\cos (2t) \end{cases}$ with $t>0$ Use a graphing utility to graph the curve defined by the given parametric equations:


text:
# How do you divide (4x^3+5x^2-2x-5)/(x^2+4)?

Apr 28, 2017

$4 x + 5 - \frac{18 x + 25}{{x}^{2} + 4}$

#### Explanation:

One way is to use the divisor as a factor in the numerator.

$\textcolor{m a \ge n t a}{\text{Add/Subtract}}$ terms that are being added/subtracted as a consequence.

$\text{consider the numerator}$

$\textcolor{red}{4 x} \left({x}^{2} + 4\right) \textcolor{m a \ge n t a}{- 16 x} \textcolor{red}{+ 5} \left({x}^{2} + 4\right) \textcolor{m a \ge n t a}{- 20} - 2 x - 5$

$= \textcolor{red}{4 x} \left({x}^{2} + 4\right) \textcolor{red}{+ 5} \left({x}^{2} + 4\right) - 18 x - 25$

$\text{quotient " =color(red)(4x+5), "remainder } = - \left(18 x + 25\right)$

$\Rightarrow \frac{4 {x}^{3} + 5 {x}^{2} - 2 x - 5}{{x}^{2} + 4} = 4 x + 5 - \frac{18 x + 25}{{x}^{2} + 4}$


text:
## Cryptology ePrint Archive: Report 2000/036

Using fewer Qubits in Shor's Factorization Algorithm via Simultaneous Diophantine Approximation

Jean-Pierre Seifert

Abstract: While quantum computers might speed up in principle certain computations dramatically, in pratice, though quantum computing technology is still in its infancy. Even we cannot clearly envison at present what the hardware of that machine will be like. Nevertheless, we can be quite confident that it will be much easier to build any practical quantum computer operating on a few number of quantum bits rather than one operating on a huge number of of quantum bits. It is therefore of big practical impact to use the resource of quantum bits very spare, i.e., to find quantum algorithms which use as few as possible quantum bits.

Here, we present a method to reduce the number of actually needed qubits in Shor's algorithm to factor a composite number $N$. Exploiting the inherent probabilism of quantum computation we are able to substitute the continued fraction algorithm to find a certain unknown fraction by a simultaneous Diophantine approximation. While the continued fraction algorithm is able to find a Diophantine approximation to a single known fraction with a denominator greater than $N^2$, our simultaneous Diophantine approximation method computes in polynomial time unusually good approximations to known fractions with a denominator of size $N^{1+\varepsilon}$, where $\varepsilon$ is allowed to be an arbitrarily small positive constant.

As these unusually good approximations are almost unique we are able to recover an unknown denominator using fewer qubits in the quantum part of our algorithm.

Category / Keywords: foundations / factoring, quantum computing

Date: received 18 Jul 2000

Contact author: Jean-Pierre Seifert at Infineon com

Available format(s): Postscript (PS) | Compressed Postscript (PS.GZ) | BibTeX Citation

[ Cryptology ePrint archive ]


text:
# What volume would a 0.250 mole sample of H_2 gas occupy, which has a pressure of 17.0 atm, and a temperature of 35°C?

Apr 29, 2017

Well, we solve the Ideal Gas equation..........and get approx. a $400 \cdot m L$ volume.

#### Explanation:

$P V = n R T$, and so $V = \frac{n R T}{P}$

$= \frac{0.250 \cdot m o l \times \left(0.0821 \cdot \frac{L \cdot a t m}{K \cdot m o l}\right) \times 308 \cdot K}{17.0 \cdot a t m}$

=??*L.

The actual pressure MIGHT be different from the value calculated here, because the pressure is somewhat elevated. At moderate pressures and high temperatures we know that ALL gases exhibit Ideal Gas behaviour.


text:
496 views

In the following figure, the area of the isosceles right triangle $\text{ABE}$ is $7$ sq.cm. If $\text{EC = 3BE},$ then the area of rectangle $\text{ABCD}$ id (insq.cm.)

1. $64$
2. $82$
3. $26$
4. $56$

Given: 1) $\text{Area of$\triangle$ABC =7 cm$^{2}$}$

2) $EC=3BE$

We know that area of triangle =$\frac{1}{2}*B*H$

so Area of $\triangle$ ABE $= \frac{1}{2}*B*H$

$\implies 7=\frac{1}{2}*B*H$

$\implies B*H=14$

This can be also written as  $\text{ BE*AB=14 cm$^{2}$}\cdots\cdots(i)$

Now area of rectangle $ABCD= AB*BC$

$\implies AB* (4*BE)$

$\implies 4*14=56$ sq cm

Note: $(BC=BE+EC\implies BE+3BE=4BE)$

Option $(D)$ is correct.
5.2k points

1
2
415 views


text:
# American Institute of Mathematical Sciences

January  2016, 12(1): 1-15. doi: 10.3934/jimo.2016.12.1

## Smoothing and sample average approximation methods for solving stochastic generalized Nash equilibrium problems

 1 School of Mathematics, Liaoning University, Liaoning 110031, China 2 School of Management, Shanghai University, Shanghai 200444, China

Received  January 2014 Revised  October 2014 Published  April 2015

In this paper, we consider the class of stochastic generalized Nash equilibrium problems (SGNEP). Such problems have a wide range of applications and have attracted significant attention recently. First, using the first order optimality condition of SGNEP and the nonlinear complementary function, we present an expected residual minimization (ERM) model for the case when the involved functions are not continuously differentiable. Then, we introduce a smoothing function, depending on a smoothing parameter, to yield a smooth approximate ERM model. We further show that the solutions of this smooth ERM model converge to the solutions of the original ERM model as the smoothing parameter tends to zero. Since the ERM formulation contains an expectation, we further propose a sample average approximate problem for the ERM model. Moreover, we show that the global optimal solutions of these approximate problems converge to the global optimal solutions of the ERM problem with probability one. Here, convergence can be achieved in two ways. One is to fix the smoothing parameter, the other is to let the smoothing parameter tend to zero as the sample increases.
Citation: Mei Ju Luo, Yi Zeng Chen. Smoothing and sample average approximation methods for solving stochastic generalized Nash equilibrium problems. Journal of Industrial & Management Optimization, 2016, 12 (1) : 1-15. doi: 10.3934/jimo.2016.12.1
##### References:
 [1] J. R. Birge, Quasi-Monte Carlo Approaches to Option Pricing,, Technical Report 94-19, (1994), 94.   Google Scholar [2] F. H. Clarke, Optimization and Nonsmooth Analysis,, Wiley, (1983).   Google Scholar [3] X. Chen and M. Fukushima, Expected residual minimization method for stochastic linear complementarity problems,, Mathematics of Operations Research, 30 (2005), 1022.  doi: 10.1287/moor.1050.0160.  Google Scholar [4] X. Chen, C. Zhang and M. Fukushima, Robust solution of monotone stochastic linear complementarity problems,, Mathematical Programming, 117 (2009), 51.  doi: 10.1007/s10107-007-0163-z.  Google Scholar [5] D. De Wolf and Y. Smeers, A stochastic version of a Stackelberg-Nash-Cournot equilibrium model,, Management Science, 43 (1997), 190.   Google Scholar [6] A. Fischer, A special Newton-type optimization method,, Optimization, 24 (1992), 269.  doi: 10.1080/02331939208843795.  Google Scholar [7] F. Facchinei and C. Kanzow, Generalized Nash equilibrium problems,, A Quarterly Journal of Operations Research, 5 (2007), 173.  doi: 10.1007/s10288-007-0054-4.  Google Scholar [8] F. Facchinei and J. S. Pang, Finite-Dimensional Variational Inequalities and Complementarity Problems,, Springer-Verlag, (2003).  doi: 10.1007/b97544.  Google Scholar [9] H. Fang, X. Chen and M. Fukushima, Stochastic $R_0$ matrix linear complementarity problems,, SIAM Journal on Optimization, 18 (2007), 482.  doi: 10.1137/050630805.  Google Scholar [10] G. Gürkan, A. Y. Özge and S. M. Robinson, Sample-path solution of stochastic variational inequalities,, Mathematical Programming, 84 (1999), 313.  doi: 10.1007/s101070050024.  Google Scholar [11] J. Gao and Y. Liu, Stochastic Nash equilibrium with a numerical solution method,, Computer Science, 3496 (2005), 811.  doi: 10.1007/11427391_130.  Google Scholar [12] J. B. Krawczyk, Numerical solutions to coupled-constraint (or generalised Nash) equilibrium problems,, Computational Management Science, 4 (2007), 183.  doi: 10.1007/s10287-006-0033-9.  Google Scholar [13] C. Ling, L. Qi, G. Zhou and L. Caccetta, The $SC^1$ property of an expected residual function arising from stochastic complementarity problems,, Operations Research Letters, 36 (2008), 456.  doi: 10.1016/j.orl.2008.01.010.  Google Scholar [14] G. H. Lin, X. Chen and M. Fukushima, New restricted NCP function and their applications to stochastic NCP and stochastic MPEC,, Optimization, 56 (2007), 641.  doi: 10.1080/02331930701617320.  Google Scholar [15] G. H. Lin and M. Fukushima, New reformulations for stochastic nonlinear complementarity problems,, Optimization Methods and Software, 21 (2006), 551.  doi: 10.1080/10556780600627610.  Google Scholar [16] P. Y. Li, Z. F. He and G. H. Lin, Sampling average approximation method for a class of stochastic Nash equilibrium problems,, Optimization Methods and Software, 28 (2013), 785.  doi: 10.1080/10556788.2012.750321.  Google Scholar [17] H. Mukaidani, Stochastic Nash equilibrium seeking for games with general nonlinear payoffs,, SIAM Journal on Control and Optimization, 49 (2011), 1659.  doi: 10.1137/100811738.  Google Scholar [18] H. Niederreiter, Random Number Generation and Quasi-Monte Carlo Methods,, Philadelphia, (1992).  doi: 10.1137/1.9781611970081.  Google Scholar [19] J. F. Nash, Non-Cooperative games,, Annals of Mathematics, 54 (1951), 286.  doi: 10.2307/1969529.  Google Scholar [20] R. T. Rockafellar and R. J. B.wets, Variational Analysis,, Springer-Verlag, (1998).  doi: 10.1007/978-3-642-02431-3.  Google Scholar [21] A. Shapiro, Monte Carlo sampling approch to stochastic programming,, European Series of Applied and Industrial Mathematics: Proceeding, 13 (2003), 65.   Google Scholar [22] A. Shapiro, Monte carlo sampling methods, stochastic programming,, Handbooks in Operations Research and Management Science, 10 (2003), 353.  doi: 10.1016/S0927-0507(03)10006-0.  Google Scholar [23] A. Shapiro and H. F. Xu, Stochasic mathematical programs with equiblbrium constraints, modelling and sample average approximation,, Optimization, 57 (2008), 395.  doi: 10.1080/02331930801954177.  Google Scholar [24] P. Tseng, Growth behavior of a class of merit functions for the nonlinear complementarity problem,, Journal of Optimization Theory and Applications, 89 (1996), 17.  doi: 10.1007/BF02192639.  Google Scholar [25] H. F. Xu and D. L. Zhang, Stochastic Nash equilibrium problems: Sample average approximation and applications,, Computational Optimization and Applications, 55 (2013), 597.  doi: 10.1007/s10589-013-9538-7.  Google Scholar [26] H. F. Xu and D. L. Zhang, Smooth sample average appproximation of stationary points in nonsmooth stochastic optimization and applications,, Mathematical Programming Series A, 119 (2009), 371.  doi: 10.1007/s10107-008-0214-0.  Google Scholar [27] Y. H. Yuan, L. W. Zhang and Y. Wu, A smoothing Newton method based on sample average approximation for a class of stochastic generalized Nash equilibrium problems,, Pacific Journal of Optimization, ().   Google Scholar [28] C. Zhang and X. Chen, Stochastic nonlinear complementarity problem and applications to traffic equilibrium under uncertainty,, Journal of Optimization Theory and Applications, 137 (2008), 277.  doi: 10.1007/s10957-008-9358-6.  Google Scholar

show all references

##### References:
 [1] J. R. Birge, Quasi-Monte Carlo Approaches to Option Pricing,, Technical Report 94-19, (1994), 94.   Google Scholar [2] F. H. Clarke, Optimization and Nonsmooth Analysis,, Wiley, (1983).   Google Scholar [3] X. Chen and M. Fukushima, Expected residual minimization method for stochastic linear complementarity problems,, Mathematics of Operations Research, 30 (2005), 1022.  doi: 10.1287/moor.1050.0160.  Google Scholar [4] X. Chen, C. Zhang and M. Fukushima, Robust solution of monotone stochastic linear complementarity problems,, Mathematical Programming, 117 (2009), 51.  doi: 10.1007/s10107-007-0163-z.  Google Scholar [5] D. De Wolf and Y. Smeers, A stochastic version of a Stackelberg-Nash-Cournot equilibrium model,, Management Science, 43 (1997), 190.   Google Scholar [6] A. Fischer, A special Newton-type optimization method,, Optimization, 24 (1992), 269.  doi: 10.1080/02331939208843795.  Google Scholar [7] F. Facchinei and C. Kanzow, Generalized Nash equilibrium problems,, A Quarterly Journal of Operations Research, 5 (2007), 173.  doi: 10.1007/s10288-007-0054-4.  Google Scholar [8] F. Facchinei and J. S. Pang, Finite-Dimensional Variational Inequalities and Complementarity Problems,, Springer-Verlag, (2003).  doi: 10.1007/b97544.  Google Scholar [9] H. Fang, X. Chen and M. Fukushima, Stochastic $R_0$ matrix linear complementarity problems,, SIAM Journal on Optimization, 18 (2007), 482.  doi: 10.1137/050630805.  Google Scholar [10] G. Gürkan, A. Y. Özge and S. M. Robinson, Sample-path solution of stochastic variational inequalities,, Mathematical Programming, 84 (1999), 313.  doi: 10.1007/s101070050024.  Google Scholar [11] J. Gao and Y. Liu, Stochastic Nash equilibrium with a numerical solution method,, Computer Science, 3496 (2005), 811.  doi: 10.1007/11427391_130.  Google Scholar [12] J. B. Krawczyk, Numerical solutions to coupled-constraint (or generalised Nash) equilibrium problems,, Computational Management Science, 4 (2007), 183.  doi: 10.1007/s10287-006-0033-9.  Google Scholar [13] C. Ling, L. Qi, G. Zhou and L. Caccetta, The $SC^1$ property of an expected residual function arising from stochastic complementarity problems,, Operations Research Letters, 36 (2008), 456.  doi: 10.1016/j.orl.2008.01.010.  Google Scholar [14] G. H. Lin, X. Chen and M. Fukushima, New restricted NCP function and their applications to stochastic NCP and stochastic MPEC,, Optimization, 56 (2007), 641.  doi: 10.1080/02331930701617320.  Google Scholar [15] G. H. Lin and M. Fukushima, New reformulations for stochastic nonlinear complementarity problems,, Optimization Methods and Software, 21 (2006), 551.  doi: 10.1080/10556780600627610.  Google Scholar [16] P. Y. Li, Z. F. He and G. H. Lin, Sampling average approximation method for a class of stochastic Nash equilibrium problems,, Optimization Methods and Software, 28 (2013), 785.  doi: 10.1080/10556788.2012.750321.  Google Scholar [17] H. Mukaidani, Stochastic Nash equilibrium seeking for games with general nonlinear payoffs,, SIAM Journal on Control and Optimization, 49 (2011), 1659.  doi: 10.1137/100811738.  Google Scholar [18] H. Niederreiter, Random Number Generation and Quasi-Monte Carlo Methods,, Philadelphia, (1992).  doi: 10.1137/1.9781611970081.  Google Scholar [19] J. F. Nash, Non-Cooperative games,, Annals of Mathematics, 54 (1951), 286.  doi: 10.2307/1969529.  Google Scholar [20] R. T. Rockafellar and R. J. B.wets, Variational Analysis,, Springer-Verlag, (1998).  doi: 10.1007/978-3-642-02431-3.  Google Scholar [21] A. Shapiro, Monte Carlo sampling approch to stochastic programming,, European Series of Applied and Industrial Mathematics: Proceeding, 13 (2003), 65.   Google Scholar [22] A. Shapiro, Monte carlo sampling methods, stochastic programming,, Handbooks in Operations Research and Management Science, 10 (2003), 353.  doi: 10.1016/S0927-0507(03)10006-0.  Google Scholar [23] A. Shapiro and H. F. Xu, Stochasic mathematical programs with equiblbrium constraints, modelling and sample average approximation,, Optimization, 57 (2008), 395.  doi: 10.1080/02331930801954177.  Google Scholar [24] P. Tseng, Growth behavior of a class of merit functions for the nonlinear complementarity problem,, Journal of Optimization Theory and Applications, 89 (1996), 17.  doi: 10.1007/BF02192639.  Google Scholar [25] H. F. Xu and D. L. Zhang, Stochastic Nash equilibrium problems: Sample average approximation and applications,, Computational Optimization and Applications, 55 (2013), 597.  doi: 10.1007/s10589-013-9538-7.  Google Scholar [26] H. F. Xu and D. L. Zhang, Smooth sample average appproximation of stationary points in nonsmooth stochastic optimization and applications,, Mathematical Programming Series A, 119 (2009), 371.  doi: 10.1007/s10107-008-0214-0.  Google Scholar [27] Y. H. Yuan, L. W. Zhang and Y. Wu, A smoothing Newton method based on sample average approximation for a class of stochastic generalized Nash equilibrium problems,, Pacific Journal of Optimization, ().   Google Scholar [28] C. Zhang and X. Chen, Stochastic nonlinear complementarity problem and applications to traffic equilibrium under uncertainty,, Journal of Optimization Theory and Applications, 137 (2008), 277.  doi: 10.1007/s10957-008-9358-6.  Google Scholar
 [1] Junichi Minagawa. On the uniqueness of Nash equilibrium in strategic-form games. Journal of Dynamics & Games, 2020, 7 (2) : 97-104. doi: 10.3934/jdg.2020006 [2] Zhihua Zhang, Naoki Saito. PHLST with adaptive tiling and its application to antarctic remote sensing image approximation. Inverse Problems & Imaging, 2014, 8 (1) : 321-337. doi: 10.3934/ipi.2014.8.321 [3] Luke Finlay, Vladimir Gaitsgory, Ivan Lebedev. Linear programming solutions of periodic optimization problems: approximation of the optimal control. Journal of Industrial & Management Optimization, 2007, 3 (2) : 399-413. doi: 10.3934/jimo.2007.3.399 [4] J. Frédéric Bonnans, Justina Gianatti, Francisco J. Silva. On the convergence of the Sakawa-Shindo algorithm in stochastic control. Mathematical Control & Related Fields, 2016, 6 (3) : 391-406. doi: 10.3934/mcrf.2016008 [5] Bin Pei, Yong Xu, Yuzhen Bai. Convergence of p-th mean in an averaging principle for stochastic partial differential equations driven by fractional Brownian motion. Discrete & Continuous Dynamical Systems - B, 2020, 25 (3) : 1141-1158. doi: 10.3934/dcdsb.2019213 [6] Naeem M. H. Alkoumi, Pedro J. Torres. Estimates on the number of limit cycles of a generalized Abel equation. Discrete & Continuous Dynamical Systems - A, 2011, 31 (1) : 25-34. doi: 10.3934/dcds.2011.31.25 [7] Fernando P. da Costa, João T. Pinto, Rafael Sasportes. On the convergence to critical scaling profiles in submonolayer deposition models. Kinetic & Related Models, 2018, 11 (6) : 1359-1376. doi: 10.3934/krm.2018053 [8] Alberto Bressan, Carlotta Donadello. On the convergence of viscous approximations after shock interactions. Discrete & Continuous Dynamical Systems - A, 2009, 23 (1&2) : 29-48. doi: 10.3934/dcds.2009.23.29 [9] Caifang Wang, Tie Zhou. The order of convergence for Landweber Scheme with $\alpha,\beta$-rule. Inverse Problems & Imaging, 2012, 6 (1) : 133-146. doi: 10.3934/ipi.2012.6.133 [10] Mats Gyllenberg, Jifa Jiang, Lei Niu, Ping Yan. On the classification of generalized competitive Atkinson-Allen models via the dynamics on the boundary of the carrying simplex. Discrete & Continuous Dynamical Systems - A, 2018, 38 (2) : 615-650. doi: 10.3934/dcds.2018027 [11] Diana Keller. Optimal control of a linear stochastic Schrödinger equation. Conference Publications, 2013, 2013 (special) : 437-446. doi: 10.3934/proc.2013.2013.437 [12] Seung-Yeal Ha, Dongnam Ko, Chanho Min, Xiongtao Zhang. Emergent collective behaviors of stochastic kuramoto oscillators. Discrete & Continuous Dynamical Systems - B, 2020, 25 (3) : 1059-1081. doi: 10.3934/dcdsb.2019208 [13] María J. Garrido-Atienza, Bohdan Maslowski, Jana  Šnupárková. Semilinear stochastic equations with bilinear fractional noise. Discrete & Continuous Dynamical Systems - B, 2016, 21 (9) : 3075-3094. doi: 10.3934/dcdsb.2016088 [14] Ardeshir Ahmadi, Hamed Davari-Ardakani. A multistage stochastic programming framework for cardinality constrained portfolio optimization. Numerical Algebra, Control & Optimization, 2017, 7 (3) : 359-377. doi: 10.3934/naco.2017023 [15] Haibo Cui, Haiyan Yin. Convergence rate of solutions toward stationary solutions to the isentropic micropolar fluid model in a half line. Discrete & Continuous Dynamical Systems - B, 2020  doi: 10.3934/dcdsb.2020210 [16] Nhu N. Nguyen, George Yin. Stochastic partial differential equation models for spatially dependent predator-prey equations. Discrete & Continuous Dynamical Systems - B, 2020, 25 (1) : 117-139. doi: 10.3934/dcdsb.2019175 [17] Longxiang Fang, Narayanaswamy Balakrishnan, Wenyu Huang. Stochastic comparisons of parallel systems with scale proportional hazards components equipped with starting devices. Journal of Industrial & Management Optimization, 2020  doi: 10.3934/jimo.2021004 [18] Shihu Li, Wei Liu, Yingchao Xie. Large deviations for stochastic 3D Leray-$\alpha$ model with fractional dissipation. Communications on Pure & Applied Analysis, 2019, 18 (5) : 2491-2509. doi: 10.3934/cpaa.2019113 [19] Shanjian Tang, Fu Zhang. Path-dependent optimal stochastic control and viscosity solution of associated Bellman equations. Discrete & Continuous Dynamical Systems - A, 2015, 35 (11) : 5521-5553. doi: 10.3934/dcds.2015.35.5521

2019 Impact Factor: 1.366


text:
# How can a Gaussian pulse be used to flip a qubit?

from qiskit import *
from qiskit.pulse.library import Gaussian
from qiskit import pulse
from qiskit.test.mock import FakeArmonk
qc = QuantumCircuit(1, 1)
qubit = 0

qc.measure(0, 0)
backend = FakeArmonk()

pulse.play(Gaussian(duration=1200, amp=0.1409018732350299, sigma=32), pulse.drive_channel(0))

reg = pulse.measure(qubit)

h_q0.draw()

job = execute(qc, backend, shots=8000)
from qiskit.tools.monitor import job_monitor
job_monitor(job)
result = job.result()
counts = result.get_counts()
print(counts)
{'0': 7810, '1': 190}

Above is the code that I am working with. I want to make the Gaussian pulse flip the qubit, so that most of the shots are in the 1 state instead of the 0 state. As a right now, the Gaussian pulse has no impact on the results of the job. I am looking at Chapter 6.1 of the Qiskit textbook, but cannot find anything that directly helps me. How would I get the Gaussian pulse involved and have it flip the output of the job?

• I haven't tried your code, but I'm pretty sure you need to delay the measurement pulse until after the Gaussian has finished Aug 12 at 10:50


text:
# Probability of drawing

The bag contains 3 red, 4 black and 2 white balls. What is the probability of drawing a red and a white ball in two successive draws, each ball being put back after it is drawn?
(A) 2/27
(B) 1/9
(C) 1/3
(D) 4/27

(E) 2/9

This is with replacement case

$P=2*\frac{3}{9}*\frac{2}{9}=\frac{4}{27}$

We are multiplying by 2 as there are two possible wining scenarios RW and WR.


text:
## anonymous 3 years ago HELP! who can explain derivatives :( let f(x)= (x^3+3x+8)^2 F'(x)= F'(2)=

1. anonymous

use the chain rule get $F'(x)=2(x^2+3x+8)(3x^2+3)$

2. anonymous

I am very bad with derivatives. I missed the whole lesson de to being sick. can we start from the beginning?

3. anonymous

how do we use the chain rule?

4. anonymous

you have something squared the derivative of something squared is two times something, times the derivative of something

5. anonymous

for example, the derivative of $$\sin^2(x)$$ is $$2\sin(x)\cos(x)$$

6. anonymous

the derivative of $$x+\sqrt{x}+\tan(x))^2$$ is $2(x+\sqrt{x}+\tan(x))(1+\frac{1}{2\sqrt{x}}+\sec^2(x))$

7. anonymous

okay

8. anonymous

so how do we begin this problem?

9. anonymous

to find the derivative we need to place the exponent in front... correct?

10. anonymous

is the derivative for f'(x) = 2X^2+6X+16?