## Solution to User Initial HTTP Requests Unencrypted Despite HTTPS Redirection?

It is my understanding that requests from a client browser to a webserver will initially follow the specified protocol e.g, HTTPS, and default to HTTP if not specified (Firefox Tested). On the server side it is desired to enforce a strict type HTTPS for all connections for the privacy of request headers and as a result HTTPS redirections are used. The problem is that any initial request where the client does not explicitly request HTTPS will be sent unencrypted. For example, client instructs browser with the below URL command.

google.com will redirect the client browser to use HTTPS but the initial HTTP request and GET parameters were already sent unencrypted possibly compromising the privacy of the client. Obviously there is nothing full-proof that can be done by the server to mitigate this vulnerability but:

1. Could this misuse compromise the subsequent TLS security possibly through a known-plaintext
attack (KPA)?
2. Are there any less obvious measures that can be done to mitigate this possibly through some DNS protocol solution?
3. Would it be sensible for a future client standard to always initially attempt with HTTPS as the default?

## Approximate solution of a nonlinear ODE in the form of a Fourier series containing the coefficients of the initial ODE

In this topic we considering nonlinear ODE:

$$\frac{dx}{dt}= (x^4) \cdot a_1 \cdot sin(\omega_1 \cdot t)-a_1 \cdot sin(\omega_1 \cdot t + \frac{\pi}{2})$$ – Chini ODE

And system of nonlinears ODE:

$$\frac{dx}{dt}= (x^4+y^4) \cdot a_1 \cdot sin(\omega_1 \cdot t)-a_1 \cdot sin(\omega_1 \cdot t + \frac{\pi}{2})$$

$$\frac{dy}{dt}= (x^4+y^4) \cdot a_2 \cdot sin(\omega_2 \cdot t)-a_2 \cdot sin(\omega_2 \cdot t + \frac{\pi}{2})$$

Chini ODE’s NDSolve in Mathematica:

pars = {a1 = 0.25, \[Omega]1 = 1} sol1 = NDSolve[{x'[t] == (x[t]^4) a1 Sin[\[Omega]1 t] - a1 Cos[\[Omega]1 t], x[0] == 1}, {x}, {t, 0, 200}] Plot[Evaluate[x[t] /. sol1], {t, 0, 200}, PlotRange -> Full] 

System of Chini ODE’s NDSolve in Mathematica:

pars = {a1 = 0.25, \[Omega]1 = 3, a2 = 0.2, \[Omega]2 = 4} sol2 = NDSolve[{x'[t] == (x[t]^4 + y[t]^4) a1 Sin[\[Omega]1 t] - a1 Cos[\[Omega]1 t], y'[t] == (x[t]^4 + y[t]^4) a2 Sin[\[Omega]2 t] - a2 Cos[\[Omega]2 t], x[0] == 1, y[0] == -1}, {x, y}, {t, 0, 250}] Plot[Evaluate[{x[t], y[t]} /. sol2], {t, 0, 250}, PlotRange -> Full] 

There is no exact solution to these equations, therefore, the task is to obtain an approximate solution.

Using AsymptoticDSolveValue was ineffective, because the solution is not expanded anywhere except point 0.

The numerical solution contains a strong periodic component; moreover, it is necessary to evaluate the oscillation parameters. Earlier, we solved this problem with some users as numerically: Estimation of parameters of limit cycles for systems of high-order differential equations (n> = 3)

How to approximate the solution of the equation by the Fourier series so that it contains the parameters of the original differential equation in symbolic form, namely $$a_1$$, $$\omega_1$$, $$a_2$$ and $$\omega_2$$.

## PDA with more than one initial state

I’m wondering if PDAs with more than one initial states are also accepting context free languages.

If found that question on this site about NFAs and would like to know if this answer is also valid for PDAs if one defines a new single initial state and connects this with the former initial states using $$\epsilon : \epsilon \to \epsilon$$ transitions?

## ORA-01658: unable to create INITIAL extent for segment in tablespace SYSAUX; JOB_SCHEDULER is biggest occupant

DBMS_SCHEDULER is occupying all of my SYSAUX tablespace. I ran dbms_scheduler.purge_log which deleted 100 million rows from dba_scheduler_job_run_details, however v$sysaux_occupants and the data file size remain unchanged. Is there some additional action I need to take to clear the SYSAUX tablespace of DBMS_SCHEDULER generated data? Attempting to insert a single row into a newly created table in my regular tablespace fails with: ORA-01658: unable to create INITIAL extent for segment in tablespace SYSAUX  I can see that JOB_SCHEDULER is taking up 92.4% of the SYSAUX tablespace by querying v$ sysaux_occupants:

SELECT     occupant_name,                         round (sum(space_usage_kbytes) * 100 / sum (sum(space_usage_kbytes)) over (), 2) Pct FROM v$sysaux_occupants GROUP BY occupant_name ORDER BY 2 desc NULLAS LAST ;  I originally had over 100 million rows in dba_scheduler_job_run_details. Yesterday, I ran the purge command (which took 3.5 hours): BEGIN dbms_scheduler.purge_log; END; /  Today, dba_scheduler_job_run_details has less than 1K rows. However, the query on v$ sysaux_occupants is unchanged; today it still says JOB_SCHEDULER is occupying 92.4%. Likewise querying my data file sizes show that SYSAUX is still maxed out:

select d.TABLESPACE_NAME, d.FILE_NAME, d.BYTES/1024/1024 SIZE_MB, d.AUTOEXTENSIBLE, d.MAXBYTES/1024/1024 MAXSIZE_MB, d.INCREMENT_BY*(v.BLOCK_SIZE/1024)/1024 INCREMENT_BY_MB from dba_data_files d,     v\$  datafile v where d.FILE_ID = v.FILE# order by d.TABLESPACE_NAME, d.FILE_NAME; 

It seems like I have not actually deleted the space consumed by DBMS_SCHEDULER.

Is there some step I am missing to clean up all the space consumed by DBMS_SCHEDULER?

## Must a monk’s Flurry of Blows attacks occur after the initial (and extra) attack from the Attack action?

Looking at the wording of Flurry of Blows, I may be overthinking it, but the description of the feature (PHB, p. 78) says:

Immediately after you take the Attack action on your turn, you can spend 1 ki point to make two unarmed strikes as a bonus action.

Does this imply that a 5th-level (or higher) monk must finish the Attack action (initial attack + extra attack) and only afterward can optionally use the Flurry of Blows bonus action immediately?

Or does “take” mean that a monk must start/commit to doing an Attack action, and before finishing the Attack action (or even make any attack rolls), they can initiate Flurry of Blows to make two more unarmed strikes? Can the Flurry of Blows attacks be before (or be interspersed in any order with) the two attacks from the Attack action?

Somewhat relevant is Mike Mearls’ October 2014 tweet that movement can occur in-between/during Flurry of Blows attacks.

My thought is to gain the benefits of the Open Hand monk’s knockdown ability tied to Flurry of Blows, and benefit from the prone status on the two attacks from the Attack action.

Example:

1. First Flurry of Blows attack; target fails Dex save and is knocked prone
2. First attack from the Attack action – target dies
3. Move to new target and use second Flurry of Blows attack; target fails Dex save and becomes prone
4. Second attack from the Attack action

(Alternatively using the Flurry benefits to remove reactions, etc.)

## If the initial target of the Hex spell is reduced to 0 HP, can the curse be moved to an unseen target or one out of range?

To originally cast the spell hex, you must target “a creature you can see within range”. The spell says that if the target drops to 0 hit points before the spell ends, the caster can use a bonus action on a subsequent turn to move the curse to a new creature. However, it does not say that the new creature being cursed has to be seen or within range.

If the initial target of hex is reduced to 0 HP, can the curse be moved to an unseen target or one out of range?

Rules as Written, it seems possible to do so, but that seems a bit overpowered.

## PDE initial condition problem

I have a general question, how do practically create/use initial conditions for numerical solution of PDE (four coupled equations)? The problem is when the initial conditions are (non-constant) functions that initially have the value 0., ie $$f[0, t] == 0$$, I don’t know if this is possible use it in Wolfram Mathematica when numerically solving with the “MethodOfLines” method. I know that if I solve such a problem using some numerical method, I have to set the initial conditions in some (small) non-zero dx, eg $$f[dx, t] = dfx$$, where $$dfx$$ is very small. How does it work in Wolfram Mathematica? Or what would you suggest? If I choose a way of using small dx, I don’t know what values should be $$dfx$$ (for four different initial functions).

1) I can find some solution, but it suffers problems near the initial value. One function goes to zero very fast and affects solutions of other functions which also go to zero at this initial value but not so fast. It leads to destabilization of solution (in higher times).

2)
When I check initial functions with solution in $$t=0$$. There are differences. In some functions in negligible ratio range (about 10^-20) but in some function in ratio range about 10^-2 even it changes a shape of function (small step). Can you advice?

## Are elements of the Hash Table’s backing array Linked Lists from the initial point when using Separate Chaining?

As usual, did quite a research in different books and academic articles, but can’t really get a clear picture.

For the Hashing Collision resolution in Hash Tables, we have one very popular strategy for resolving it, and it’s called Separate Chaining.

I’m aware, that in the Separate Chaining strategy, elements, which end up being collided due to hashed into same particular index, are (or will be becoming) Linked Lists.

One instructor even said so, that:

Elements of the backing array in separate chaining, are linked lists.

My question is following: is the type of backing array Linked List from the moment of creation of Hash Table (during separate chaining strategy implementation), or it gets converted to that array after first collision? because, having Linked Lists as each element of the backing array means, that those Linked Lists, should be a list of the elements, which in turn, are Entries/Buckets of a pair of key-value. This all really consumes a lot of memory and resource, I reckon.

Thank you.

## Find the missing initial conditions for system of ODES

I want to solve the following system of ODEs:

   s1 (t) = -(k1*s1 *(k2*s2 + s3))/N,    s2 (t) = ((k1*s1 *(k2*s2 + s3))/N) - k3*s2,     s3' (t) = k3*s2 - k4*s3      s4' (t) = k4*s3 

where k1=0.4029;k2=0.7;k3=0.41;k4=0.182; N=s1+s2+s3+s4; my problem I don’t have initial conditions, is there any possible way in mathematica to find the initial conditions and solve the system?

Thanks

## In completely fair scheduler in Linux, how to calculate the initial virtual run time of a process

I am trying to implement a completely fair scheduler. I want to know how to calculate the initial value of virtual run time of a process in order to insert the process into a red black tree