text:
\subsection{Our Models and Results}
We only consider the goal of minimizing the
\emph{average} (or total)
metric distance of all voters from the winning candidate.%
\footnote{Recall that \cite{anshelevich:bhardwaj:postl} and several
  follow-up articles studied both the average and median distance.}
Our main result, proved in Section~\ref{sec:general-lower},
is essentially a negative answer to the question of whether any voting
mechanisms can simultaneously have all three desirable properties.
We consider a model in which each voter communicates $b$ bits of
information about her ranking to the mechanism, in a single round.%
\footnote{Analyzing the distortion of multi-round deterministic
  mechanisms with limited communication is a very interesting
  direction for future work.}
Associated with each $b$-bit string \MSG is a subset \PSet{\MSG} of
rankings.
The \PSet{\MSG} must form a disjoint cover of all possible rankings.
If they did not form a cover, some voters might not have any message
to send, making the mechanism ill-defined.
And if the \PSet{\MSG} were not disjoint,
then it is not clear how a voter with multiple possible messages \MSG
would make the (non-deterministic) choice which one to send;
in particular, this choice could depend on the actual metric
distances, and it might require much more subtle definitions to
place meaningful restrictions on a mechanism to not exploit such
information.
Each voter communicates the (unique) \MSG such that her permutation
is in \PSet{\MSG}.
We require that the same set \PSet{\MSG} is associated with the string \MSG,
regardless of the identity of the voter sending the string.\footnote{%
  Our results require this assumption. While studying the power of
  mechanisms that allow different voters to use different encodings of
  their preferences would be interesting theoretically, voting
  mechanisms which treat votes differently \emph{a priori} tend to not
  be accepted in practice.}
Under this model, in Section~\ref{sec:general-lower},
we prove the following lower bound:

\begin{theorem} \label{thm:general-lower-intro}
Every one-round deterministic voting mechanism in which each voter
sends only a $b$-bit string to the mechanism has
distortion at least $\frac{2n-4}{b} - 1$.
\end{theorem}

Most mechanisms with limited communication are of a fairly specific
form: voters can communicate only their choices in a (small) set $K$ of
$k$ positions of their ranking,
typically at the top or bottom of their ballots.
(Either giving the candidate for each such position,
or specifying them as a set, as in $k$-approval.)
For such restricted mechanisms, a simpler proof
(in Section~\ref{sec:simple-lower}) gives a lower bound
that is stronger by a factor $\Theta(\log n)$:

\begin{theorem} \label{thm:simple-lower-intro}
  Any deterministic one-round social choice rule which receives,
  from each voter,
  no information about candidates outside positions $K$ in her ranking,
  has distortion at least
  $\frac{2n-\SetCard{K}}{\SetCard{K}}$.
\end{theorem}

The proof of Theorem~\ref{thm:simple-lower-intro} is significantly
easier and cleaner than the proof of
Theorem~\ref{thm:general-lower-intro},
while still containing some of the key ideas.
Therefore, we present the proof of
Theorem~\ref{thm:simple-lower-intro} \emph{before} that of
Theorem~\ref{thm:general-lower-intro}.

Theorem~\ref{thm:simple-lower-intro} provides a generalization
of Theorem~1 of the recent work
\cite{fain:goel:munagala:prabhu:referee},
which proves linear distortion for the special case when $K$ consists of
the top $k$ positions, for constant $k$.
In fact, \cite{fain:goel:munagala:prabhu:referee} shows these lower
bounds on the \emph{expected squared distortion} of randomized
mechanisms;
this directly implies the same bounds for deterministic mechanisms.

The fact that the lower bound of Theorem~\ref{thm:simple-lower-intro}
is stronger than that of Theorem~\ref{thm:general-lower-intro}
by a factor of $\Theta(\log n)$
is discussed in more detail in Section~\ref{sec:general-lower}.
To see it most immediately,
consider the case $\SetCard{K} = k = \omega(n/\log n), k = o(n)$.
Because $k = o(n)$,
Theorem~\ref{thm:simple-lower-intro} provides a super-constant lower bound
on the distortion.
On the other hand, communicating the positions of $k$ candidates
requires $b = \omega(n)$ bits, so the lower bound
of Theorem~\ref{thm:general-lower-intro} is vacuous.
Closing this $\Theta(\log n)$ gap is an interesting direction for
future work, discussed in Section~\ref{sec:conclusions}.

The reason we consider Theorem~\ref{thm:general-lower-intro} our main
contribution is that it helps us pinpoint the source of high
distortion.
Several recent works have shown lower bounds on the distortion of
different specific classes of social choice rules,
such as score-based rules \cite{anshelevich:bhardwaj:elkind:postl:skowron}
or the above-mentioned top-$k$ ballots \cite{fain:goel:munagala:prabhu:referee}.
Our result implies that regardless of the intricacy of the mechanism,
low communication (within the context studied here) and determinism
are enough to force high distortion.
Communication as a measure of complexity is fairly natural, as
evidenced by the mechanisms typically used in practice for large
numbers of alternatives.
Communication can also be regarded as a proxy for cognitive effort
imposed on the voters, although admittedly, the computation of a
message \MSG in a general $b$-bit bounded mechanism may still require
the voter to first determine her full ranking of all candidates.

\smallskip

The results of Theorems~\ref{thm:general-lower-intro} and
\ref{thm:simple-lower-intro} are lower bounds, raising the question of
how small one can make a mechanism's distortion when communication is
limited.
In Section~\ref{sec:upper}, we address this question, proving the
following theorem.

\begin{theorem} \label{thm:upper-intro}
  There is a one-round deterministic social choice rule which,
  given only each voter's top $k$ candidates (in order),
  selects a candidate with distortion at most
  $\frac{79n}{k}$.
\end{theorem}

The deterministic social choice rule of Theorem~\ref{thm:upper-intro}
is a generalization of the Copeland rule to such top-$k$ ballots.
Up to constant factors,\footnote{%
  An application of Corollary~5.3 of \cite{DistortionDuality}
  gives an upper bound of $\frac{12n}{k}$, which, however,
  is still far from matching the lower bound.}
the bounds of Theorems~\ref{thm:simple-lower-intro} and
\ref{thm:upper-intro} match.
Closing the gap between the upper and lower bound is likely difficult,
as even for $k=n$, the best-known lower bound of 3 does not match the
best current upper bound of $2+\sqrt{5} \approx 4.23$ due to
\cite{munagala:wang:improved};
whether there is a deterministic mechanism with metric
distortion 3 is a well-known open question.
Notice also that Theorem~\ref{thm:upper-intro} implies that knowing
each voter's ranking for a constant fraction of candidates is
sufficient to achieve constant distortion,
a fact that may not be a priori obvious.

As we discussed earlier, the main focus in this article is on
\emph{deterministic} mechanisms: as discussed earlier,
the \emph{Random Dictatorship} mechanism
has distortion strictly smaller than 3, achieving small distortion and
low communication simultaneously.%
\footnote{The amount by which it is smaller is of order $1/\SetCard{V}$;
  here, $\SetCard{V}$ is the the number of voters, which we consider ``large.''}
\cite{gross:anshelevich:xia:agree} prove a nearly matching lower bound:
they show that every randomized social choice rule in which each voter
only communicates her top $k < n/2$ candidates must have distortion at least
$3-\frac{2}{\Floor{n/k}}$.
However, even for $k=1$, this leaves a gap between the upper
bound of essentially $3$ for Random Dictatorship and the lower bound
of $3-\frac{2}{n}$.
Recently, \cite{fain:goel:munagala:prabhu:referee} shrunk this gap:
they proved that the Random Oligarchy mechanism
--- which samples three voters and outputs a majority of first-place
votes if it exists, and otherwise the choice
of a random voter among the three --- achieves expected distortion
close to $3-\frac{2}{n}$, though there still remains a small gap
between the upper and lower bounds.
As an additional result, in Section~\ref{sec:randomized},
we close this remaining gap:

\begin{theorem} \label{thm:randomized-intro}
There is a simple randomized social choice rule in which each
voter only communicates her first-choice candidate,
and which achieves distortion at most $3-\frac{2}{n}$.
\end{theorem}

\subsubsection*{Nature of Latent Distances}

The optimization objective of the mechanism is expressed in terms of
latent utilities, or more specifically, distances.
A subtle question is whether voters ``know'' their utilities for (or
distances to) candidates, or --- perhaps more philosophically ---
whether these utilities/distances are ``real.''
In general, one attractive feature of the distortion framework is that
it completely obviates the need to address this question:
when a mechanism achieves low distortion, it optimizes robustly over
all possible utility/distance functions consistent with the rankings,
and the question of whether voters could actually quantify the
utilities in a meaningful way is irrelevant.

However, when we focus on the design of mechanisms with low
communication, the question should be addressed explicitly,
as the answer has a strong impact on the design space for mechanisms.
When the mechanism designer has control not only over the
\emph{aggregation} of ballots, but also over the type of information
about voter preferences that is elicited,
this opens the door to designing mechanisms in which agents explicitly
communicate numerical estimates of their utilities for some candidates;
in turn, having such information may allow a mechanism to achieve
lower distortion (as we will see in related work below).
If agents themselves cannot quantify their utilities,
then not only is communication of a ranking imposed by the class of
typically used mechanisms, but it is inherently the only information
about the utilities that agents themselves may have access to.

Which of these two assumptions
(or something between the two along a more fine-grained spectrum)
is more realistic likely depends on the envisioned application.
For example, if software agents vote on a preferred alternative in a
mostly economically motivated setting, then it is very reasonable to
assume that the agents can compute (good approximations of) their
utilities.
On the other hand, when human voters choose between political
candidates, assuming an ability to quantify a metric distance in some
abstract space of political positions is much less realistic.
Thus, we believe that for both assumptions,
there are important and natural settings in which they are justified,
motivating studies of communication-distortion tradeoffs in both types
of scenarios.

\subsection{Related Work}

Communication complexity \cite{kushilevitz:nisan} generally studies
the required communication between multiple parties wishing to jointly
compute an outcome.
Several recent works have studied the communication required
specifically for jointly computing particular economic outcomes,
or --- conversely --- to bound the effects of limited communication on
such economic outcomes.
These include work on auctions and allocations
\cite{alon:nisan:raz:weinstein:limited-interaction,assadi:auctions-interaction,blumrosen:nisan:segal:bounded-communication,blumrosen:feldman:implementation-bounded,dobzinski:nisan:oren:efficiency-interaction},
persuasion \cite{LimitedSignaling},
and general mechanism design
\cite{mookherjee:tsumagari:communication-constraints}.
While the high-level concerns are similar across different domains,
the specific approaches and techniques do not appear to carry over.

The impact of communication more specifically
on social choice rules has been explored before;
see, for instance, \cite{boutilier:rosenschein:incomplete} for an overview.
However, most of the focus in past work has been on the number of bits
that need to be communicated in order to compute the outcome of a
\emph{particular} social choice rule, rather than on proving lower
bounds arising due to limited communication when the social choice rule
is not pre-specified.
A classic paper in this context is by Conitzer and Sandholm
\cite{conitzer:sandholm:vote-elicitation}: they study
\emph{vote elicitation} rules, i.e., protocols by which a mechanism can
interact with voters to determine the winner under a particular voting
rule while not eliciting the full ranking information.
This raises algorithmic questions about whether the information
obtained so far uniquely determines a winner as well as incentive
issues, among others, and a large amount of follow-up literature
(e.g., \cite{ding:lin:voting-partial}) has studied these issues.
Relatedly, Conitzer \cite{conitzer:eliciting-single-peaked} studies
how many comparisons need to be elicited from voters to be able to
reconstruct their complete ranking, and shows that the number is
linear (as opposed to quadratic) when preferences are single-peaked
(on the line).

Several very recent papers have explicitly considered the tradeoff between
communication and distortion in social choice,
both in deterministic and randomized settings.
Perhaps most immediately related is recent work by
Fain et al.~\cite{fain:goel:munagala:prabhu:referee}.
Their focus is on mechanisms with extremely low communication which
achieve low expected squared distortion, a measure somewhere between
expected distortion and deterministic distortion.
They prove that the Random Referee mechanism, which asks two randomly
chosen voters for their top choices, and asks a third voter to choose
between these two choices, achieves constant expected squared
distortion.
Notice that this mechanism elicits different information from
different voters.
Theorem~1 of \cite{fain:goel:munagala:prabhu:referee} shows that this
is unavoidable, in that any mechanism that only obtains top-$k$ lists
(for constant $k$), even from all voters, must have linear expected
squared distortion, implying the same result for the distortion of
deterministic mechanisms.
Our Theorem~\ref{thm:simple-lower-intro} generalizes this result for
deterministic mechanisms to non-constant $k$ and sets other than the
top $k$ positions.

Another very related piece of work is due to
Mandal et al.~\cite{mandal:procaccia:shah:woodruff},
studying the communication-distortion tradeoff in a setting where the
voters have utilities (instead of costs) for the candidates,
and these utilities are only assumed to be non-negative and normalized,
but do not need to satisfy any other properties
(such as being derived from a metric).
The other major modeling difference between our work and
\cite{mandal:procaccia:shah:woodruff} is that they assume that agents
compute their message \MSG to the mechanism directly from their
utility vector, rather than the ranking.
In particular, the mechanism can be designed to allow voters to
express the strength of their preferences, albeit in possibly coarse
form.
This allows for a choice of deterministic/randomized algorithms in two
places: (1) the voters' computation of their message, and
(2) the mechanism's aggregation of the messages into a winner.
\cite{mandal:procaccia:shah:woodruff} give upper and lower bounds for
deterministic and randomized voting rules in this setting.

The positive/algorithmic results in
\cite{mandal:procaccia:shah:woodruff} are obtained primarily by
generalizing an approach of
Benad\`{e} et al.~\cite{BNPS:distortion-rule:application},
asking voters to communicate their top few candidates as well as a
suitably rounded version of their utility for those nominated
candidates.
The bounds are improved in some parameter regimes by having the mechanism
randomly select a subset of candidates and restricting voters to choose
from this subset.

While the results of \cite{mandal:procaccia:shah:woodruff} are clearly
directly related to our work, they are not immediately comparable.
Because the utilities are not derived from metrics, the mechanisms
need to deal with much broader classes of inputs, resulting in
(generally) weaker upper bounds and stronger lower bounds.
On the other hand, the assumption that voters can explicitly quantify
their utilities --- and hence have them elicited by a mechanism ---
gives a mechanism more power than in our setting.

Another related recent piece of work is on approval-based voting,
due to Pierczy\'{n}ski and Skowron \cite{pierczynski:skowron:approval}.
While much of this work focuses on a different notion of distortion
--- analyzing the fraction of voters who \emph{approve} of the winning
candidate in the sense of being ``close enough'' ---
\cite{pierczynski:skowron:approval} also analyzes the (traditional)
distortion of approval-based voting.
Under the type of mechanism that they consider, rather than approving
a given \emph{number} of voters (as in $k$-approval),
voters approve all candidates within a given \emph{distance} of
themselves, i.e., within a ball of given radius around themselves.
This approval radius can be voter-specific or uniform across voters.
In this context, the main result of
\cite{pierczynski:skowron:approval} is to show specific constant
distortion whenever a uniform approval radius ensures that a constant
fraction of voters, bounded away from 0 and 1, have the optimum
candidate within their approval radius.\footnote{%
  In particular, when that fraction is between \quarter and \half, the
  distortion is at most 3.}
It is of course not clear how a mechanism (or the voters) could
determine such a radius.
Also note that this type of approval-based mechanism does require
voters to quantify their distances,
rather than just interact with their individual ordinal rankings.

Note that Theorem~\ref{thm:upper-intro} can be considered as somewhat
related to this result. It shows that whenever voters communicate
their top $k$ candidates, where $k$ is a constant fraction of the
number of candidates, there is a mechanism with constant distortion.
However, in contrast to the result of \cite{pierczynski:skowron:approval},
not just the identity, but also the ranking of these top $k$
candidates must be communicated; on the other hand, the theorem makes
no assumptions about whether the optimum candidate appears in any of
these top-$k$ rankings.

Low communication complexity of voter preferences is also the focus of
a recent preprint by Bentert and Skowron
\cite{bentert:skowron:few-candidates}.
They study the more ``traditional'' goal of implementing given voting
rules with low communication \cite{boutilier:rosenschein:incomplete},
but are interested in \emph{approximate} implementation of these
rules.
To make approximation meaningful, they focus on score-based rules,
which naturally assign each candidate a score (such as Borda Count,
Plurality, or MiniMax).
Then, the quality of approximation is the ratio between the score of
the winner under full information vs.~the score of the winner under
limited communication.
They focus on mechanisms in which each voter is asked to rank a small
subset of candidates; this subset is either the voter's top $k$
candidates (a deterministic mechanism) or a random subset of $k$
candidates (a randomized mechanism).

Given that the goal in \cite{bentert:skowron:few-candidates} is the
approximate implementation of specific scoring-based voting rules
rather than achieving low distortion, the results are not directly
comparable.
However, the techniques in Section~3.2 of
\cite{bentert:skowron:few-candidates} readily yield a randomized
mechanism with distortion $5+O(\epsilon)$ and very low communication
complexity per voter when the number of voters is sufficiently large.
By asking each voter to compare a uniformly random pair of candidates
(see also \cite{hansen:random-pairs}),
and using the majority of returned votes,
with high probability (by Chernoff and Union Bounds),
one obtains a tournament graph in which each directed edge $(x,y)$
corresponds to at least a $\half-\epsilon$ fraction of voters
preferring $x$ over $y$.
Then, a straightforward modification of the analysis of the distortion
of uncovered set rules in
\cite{anshelevich:bhardwaj:elkind:postl:skowron}
(or a simple application of Corollary~5.3 in \cite{DistortionDuality})
gives a distortion of $5+O(\epsilon)$.
This rule only requires each voter to compute 1 bit in total.
However, different voters are asked to answer different questions,
which is often considered undesirable.
Furthermore, the total communication complexity is $n$ bits, whereas
the Random Dictator mechanism only needs to elicit $\log_2 n$ bits
from one voter.

The recent work of Bentert and Skowron is somewhat related to earlier
work of Filmus and Oren \cite{filmus:oren:top-k-voting}:
they are also interested in the question of when top-$k$ ballots from
voters are sufficient to obtain the correct candidate.
However, \cite{filmus:oren:top-k-voting} study this question under
probabilistic models for the ballots, significantly changing the
nature of the results.

The metric-based distortion view of social choice has proved to be a
very fruitful analysis framework.
In fact, it has been extended beyond social choice to other
optimization problems in which it is natural to assume that a
mechanism only receives ordinal information;
see, e.g., \cite{anshelevich:sekar:blind,anshelevich:ordinal}.

Several modeling assumptions have been proposed that yield lower
distortion than the worst-case bounds of
\cite{anshelevich:bhardwaj:elkind:postl:skowron}.
One such assumption is termed \emph{decisiveness}
\cite{anshelevich:postl:randomized,gross:anshelevich:xia:agree}:
it posits that for every voter, there is a sufficiently clear
first choice among candidates.
When the metric space is sufficiently decisive, significantly stronger
upper bounds on the distortion can be proved.
An alternative approach was proposed in
\cite{OfThePeople,BordaRepresentative}.
The authors assumed that the candidates were ``representative,''
in that they themselves were drawn i.i.d.~uniformly from the set of
voters.
Under this assumption, the authors obtained improved expected
 distortion bounds for the case of two candidates
\cite{OfThePeople},
and constant expected distortion for Borda count and
several other position-based scoring rules \cite{BordaRepresentative}.

As mentioned above, the gap between the upper bound of 5
(achieved, e.g., by the Copeland rule)
and the lower bound of 3 has posed an
interesting open question for several years now.
One initial conjecture of \cite{anshelevich:bhardwaj:postl}
was that the Ranked Pairs mechanism might achieve a distortion of 3.
This conjecture was disproved by \cite{goel:krishnaswamy:munagala},
who showed a lower bound of 5 on the distortion of Ranked Pairs.
Very recently, Munagala and Wang \cite{munagala:wang:improved}
have presented a (deterministic) social choice rule with
 distortion at most $2+\sqrt{5} \approx 4.23$,
which is the first piece of progress towards closing the gap.

In our and much of the preceding work on metric voting,
the focus is on distortion, while ignoring incentive compatibility.
(Recall the strong impossibility result of
\cite{gibbard:manipulation,satterthwaite:voting}.)
The connection between strategy proofness and distortion in this type
of setting was studied in \cite{feldman:fiat:golomb}.

\section{Introduction} \label{sec:introduction}
\input{introduction}

\section{Preliminaries} \label{sec:preliminaries}
\input{preliminaries}

\section{A Lower Bound for $k$-Entry Social Choice Rules} \label{sec:simple-lower}
\input{simple-lower}

\section{The General Lower Bound} \label{sec:general-lower}
\input{general-lower}

\section{A Near-Matching Upper Bound} \label{sec:upper}
\input{upper}

\section{A Tight Upper Bound for Randomized Algorithms} \label{sec:randomized}
\input{randomized}

\section{Conclusions} \label{sec:conclusions}
\input{conclusions}

\subsubsection*{Acknowledgements}
The author would like to thank
Elliot Anshelevich, Yu Cheng, Shaddin Dughmi, Tyler LaBonte, Jonathan
Libgober, and Sigal Oren for useful conversations and pointers,
and anonymous reviewers for useful feedback.

\bibliographystyle{plain}

\subsection{Voters, Candidates, and Social Choice Rules}

There are $n$ candidates, which we always denote by lowercase letters
at the end of the alphabet.
Sets of candidates are denoted by uppercase letters,
and \ALLCANDS is the set of all candidates.
The preference order (or ranking) of voter $v$ over the candidates
is a bijection $\PERM[v] : \SET{1, \ldots, n} \to \ALLCANDS$,
mapping positions $i$ to the candidate $x = \Perm[v]{i}$ which voter
$v$ ranks in position $i$.
We say that $v$ (strictly) \emph{prefers} $x$ to $y$ iff
$\PermInv[v]{x} < \PermInv[v]{y}$.
When only the ranking, but not the identity, of a voter is relevant,
we will omit the subscript $v$ for legibility.
The set of all voters\footnote{%
  We will not need to reference the number of voters explicitly.
  In general, we treat the number of voters as ``much larger'' than
  the number of candidates, and are only interested in bounds in terms
  of the number of candidates.}
is denoted by \ALLVOTERS.
We write \ALLPERMS for the set of all possible rankings
$\PERM: \SET{1, \ldots, n} \to \ALLCANDS$,
and $\PERMMAT = (\Perm[v]{i})_{v \in \ALLVOTERS, i \in \SET{1, \ldots, n}}$
for the rankings of all voters, which we call the \emph{vote profile}.

In the traditional full-information view,
a \emph{social choice rule} (we use the terms
\emph{mechanism} or \emph{voting mechanism} interchangeably)
$\SCRULE : \ALLPERMS^{\ALLVOTERS} \to \ALLCANDS$
is given the rankings of all voters, i.e., \PERMMAT,
and produces as output one \emph{winning} candidate
$\WINNER = \SCRule{\PERMMAT}$.
For most of this article, we are interested only in
\emph{deterministic} social choice rules \SCRULE.

\subsection{Communication-bounded mechanisms}

Our main contribution is to consider communication-bounded social
choice rules.
As in the standard model described above,
we still only consider deterministic \emph{single-round} mechanisms,
i.e., each voter can only send a single message to the mechanism.
However, this message is now also restricted to be at most $b$ bits
long.

This induces $\PARTS = 2^b$ sets
$\PSet{1}, \PSet{2}, \ldots, \PSet{\PARTS}$ of rankings;
when the mechanism receives a message \MSG from voter $v$,
all it learns is that $\PERM[v] \in \PSet{\MSG}$.
As discussed in the introduction,
we assume that the \PSet{\MSG} form a disjoint partition of \ALLPERMS,
i.e., they are pairwise disjoint and cover all rankings:
$\bigcup_{\MSG=1}^{\PARTS} \PSet{\PARTS} = \ALLPERMS$.
The fact that \PARTS is a power of 2 is not relevant anywhere in our
proofs,
so we also consider mechanisms with arbitrary numbers \PARTS of sets.

\begin{definition}[\PARTS-communication bounded social choice rule]
\label{def:communication-bounded-rule}
An \emph{\PARTS-communication bounded social choice rule} consists of
pairwise disjoint sets
$\PSet{1}, \PSet{2}, \ldots, \PSet{\PARTS} \subseteq \ALLPERMS$
with $\bigcup_{\MSG=1}^{\PARTS} \PSet{\PARTS} = \ALLPERMS$,
and a deterministic mapping
$\SCRULE: \SET{1, \ldots, \PARTS}^{\ALLVOTERS} \to \ALLCANDS$.
\end{definition}

Communication-bounded social choice rules that are used in
practice, such as Plurality, Veto, $k$-approval, and combinations
thereof, are of a specific form:
there is a set $K$ of $k$ positions, and voters can communicate the
set of candidates they have in positions in $K$,
possibly with an ordering, but cannot communicate any additional
information about their ranking of candidates in positions outside $K$.
For such mechanisms, we will be able to prove stronger lower bounds on
the distortion, and with a significantly simpler proof.
We define them formally as follows:

\begin{definition} \label{def:k-entry-rule}
  A \emph{$k$-entry social choice rule} is an
  \PARTS-communication bounded social choice rule with the following
  additional restriction on the sets
  $\PSet{1}, \PSet{2}, \ldots, \PSet{\PARTS}$:
  there exists a set $K \subseteq \SET{1, \ldots, n}$ of at most $k$
  positions such that
  if $\PERM, \PERMP$ agree for all positions in $K$,
  i.e., $\Perm{i} = \PermP{i}$ for all $i \in K$, then
  $\PERM \in \PSet{\MSG}$ if and only if $\PERMP \in \PSet{\MSG}$.
\end{definition}

\subsection{Metric Space and Distortion}

The key modeling contribution of the metric-based distortion
\cite{anshelevich:bhardwaj:postl}
objective is to assume that all voters and candidates are
embedded in a pseudo-metric space \DIST.
\Dist{v}{x} denotes the distance between voter $v$ and candidate $x$.
Being a pseudo-metric, it satisfies non-negativity and the triangle
inequality $\Dist{v}{x} \leq \Dist{v}{y} + \Dist{v'}{y} + \Dist{v'}{x}$
for all voters $v, v'$ and candidates $x, y$.
Given our choice of defining the metric only for pairs consisting of a
voter and a candidate, symmetry is not directly relevant.
One can naturally extend the pseudo-metric to pairs of candidates or
pairs of voters, but those distances will never appear in our
mechanisms or proofs.
For our upper bounds, we explicitly allow the distance between
candidates and voters
(and thus also between pairs of candidates or pairs of voters)
to be 0; however, for improved flow, we will still refer to \DIST as
a \emph{metric}.
In our lower-bound constructions, all distances will be strictly
positive; that is, we do not exploit the increased generality for
negative results.

We say that a vote profile \PERMMAT is \emph{consistent} with the
metric \DIST, and write \Legal{\DIST}{\PERMMAT},
if $\Perm[v]{x} < \Perm[v]{y}$ whenever $\Dist{v}{x} < \Dist{v}{y}$.
That is, \PERMMAT is consistent with \DIST iff all
voters rank candidates by non-decreasing distance from themselves.
Notice that in case of ties among distances,
i.e., $\Dist{v}{x} = \Dist{v}{y}$,
several vote profiles are consistent with \DIST.
None of our results depend on any tie breaking assumptions.

The \emph{cost} of candidate $x$ is
$\Cost{x} = \sum_{v} \Dist{v}{x}$,
i.e., the sum of distances of $x$ to all voters.%
\footnote{\cite{anshelevich:bhardwaj:postl} also consider the median
  distance as an optimization objective;
  here, we only focus on the sum/average objective.}
An \emph{optimum} candidate is any candidate
$\OPT[\DIST] \in \argmin_{x \in \ALLCANDS} \Cost{x}$;
in our analysis, it will not matter which candidate is considered
``the'' optimum candidate in case of ties.

The social choice rule is handicapped by not knowing the metric \DIST,
instead only observing the consistent vote profile \PERMMAT
(or some limited information about it, when communication is restricted).
Due to this handicap, and possibly other suboptimal choices,
it will typically choose candidates with higher cost than
\Cost{\OPT}.
The \emph{distortion} of \SCRULE is the worst-case ratio between the
cost of the candidate chosen by \SCRULE,
and the optimal candidate \OPT[\DIST]
(determined with knowledge of the actual distances \DIST).
Formally,
\[
  \Distortion{\SCRULE} \; = \;
  \max_{\PERMMAT} \sup_{\DIST: \Legal{\DIST}{\PERMMAT}}
  \frac{\Cost{\SCRule{\PERMMAT}}}{\Cost{\OPT[\DIST]}}.
\]
We can think of the distortion in terms of a game between the social
choice rule and an adversary.
First, the adversary chooses the vote profile \PERMMAT.
Then, the social choice rule, knowing only \PERMMAT
(or part of that information, in case of communication restrictions),
chooses a winning candidate \WINNER = \SCRule{\PERMMAT}.
Then, the adversary chooses a metric \DIST consistent with
\PERMMAT that maximizes the ratio between the cost of the
candidate chosen by \SCRULE and the optimum candidate for \DIST.

The goal now is to define a social choice rule \SCRULE
--- under suitable constraints --- that achieves small distortion
\Distortion{\SCRULE}, and to prove lower bounds on all social choice
rules under the given constraints.

redpajama_set_name: RedPajamaArXiv


text:
2020 Honda Civic Si Long-Term Review: The Goldilocks of Sports Sedans
Minor concessions in comfort return huge gains in driver engagement.
Scott EvansAuthor
Honda Civic Full Overview
Buying a performance car often costs more than money; it costs comfort and convenience. If you're buying a 2020 Honda Civic Si, though, it doesn't have to.
The Civic Si is essentially a mono-spec vehicle. As such, it rings in at just $26,155, making it one of the cheapest sports cars on the market in the best way possible. For that price, you get 31 more horses than a standard Civic, two-mode electronically controlled dampers, and a limited-slip differential. We spec'd ours with the $200 High-Performance Tire (HPT) option, but aside from that, all you could add to this car are some dress-up parts, a wireless phone charger, and an auto-dimming rearview mirror. The last two would've been nice, but we easily lived without them.
2020 Honda Civic Si: The Cost of Caring
The Civic Si doesn't cost much in terms of comfort, either. The standard setting for the adjustable shocks is firmer than that of the average compact sedan, but not much. The shocks get firmer still in Sport mode, but that's just for when you're pushing the car on a good road. The front seats have big bolsters on the sides to keep you in place, but they're big, soft pads, not rigid extensions. If the Si is any louder inside than a standard Civic, it's not enough to notice (interior noise has long been a Civic weak spot).
The Civic Si costs almost nothing so far as convenience is concerned—provided you don't consider driving a stick shift in traffic inconvenient. In sedan guise, it gives up nothing in rear-seat space or access, and you get a big, secure trunk. And although there's no navigation option, it does come with Apple CarPlay and Android Auto compatibility so you can use your phone's navigation instead.
In fact, the Civic Si is comfortable and convenient enough that my wife and I didn't have a second thought about taking it on a three-hour journey to celebrate our anniversary at a house—with a pool—we rented. I thought for sure we'd stuff the car to the roof with clothes, food, drinks, and entertainment for a week, but we barely filled the trunk. Hours on the freeway to and from were no big deal, as the car was neither too stiff nor too loud for a road trip (nor were the seats too stiff).
On this particular trip, the Honda was just a nice little compact sedan with some extra zip for passing lane hogs. On other trips, especially those up into the mountains to go hiking, it was the best sports sedan for the money on the market (the Civic Type R is a hatchback). The composure of the chassis could teach things to more than a few sports cars that cost three times as much.
2020 Honda Civic Si Sedan: Momentous Performance
The Civic Si is what we call a momentum car. With 205 hp, it's no performance monster, but at 2,900 pounds, it's light enough to chuck about without constantly needing to slam on the stoppers. There's a delightful dance to be had in braking just enough to safely make the corner without losing any more momentum than absolutely necessary. The brakes, which aren't even upgraded past a set of performance pads, stand up to anything you can throw at them, which isn't much because again, you don't really have to slow down much for most corners. On the way out, the Civic Si's limited-slip lets you get back on the power early and pull it out of the corner, making the most of every pony. The manual transmission, the best of any this side of a Porsche, never lets you miss a shift, and the pedals are perfectly spaced for heel-toe downshifting.
Its shortcomings are few and far between. If you're something of a drag racer, this isn't the car for you. Although the Civic Si feels quicker than it is, it's still held back by an engine that lags below 3,000 rpm and runs out of steam a thousand rpm before redline. The little Honda sedan is best when hustled on a road where you can keep both its speed and the engine's speed up. Around town, you're best off shifting before the turbo switches on, and when you're hustling, short-shifting. You'd also be well advised to keep a rag in the car to protect your hand from the cool-looking but scalding-hot or freezing-cold aluminum-topped shifter. When you're done driving, make sure to wait until the engine actually stops running after you switch off the car. If you release the clutch in gear too quickly ... well, it could get ugly.
It's easy to overlook the Civic Si when the Civic Type R is right there on the lot and only $11,500 more, but whether you're on a budget or just not ready to make the compromises its more powerful kin demands, the Si delivers. It's rewarding to drive on the best roads and comfortable on the commute. Ultimately, the Civic Si demands very little in exchange for the fun it provides, leaving you with a practical sedan every other day of the week.
Read more about our long-term 2020 Honda Civic Si sedan:
Update 1: Getting to Know You
Update 2: Should You Get a Honda Civic Si or a Honda Civic Type R?
Update 3: Comfortably Sporty
POWERTRAIN/CHASSIS 2020 Honda Civic Si (Sedan)
DRIVETRAIN LAYOUT Front-engine, FWD
ENGINE TYPE Turbocharged I-4, alum block/head
VALVETRAIN DOHC, 4 valves/cyl
DISPLACEMENT 91.4 cu in/1,498 cc
POWER (SAE NET) 205 hp @ 5,700 rpm
TORQUE (SAE NET) 192 lb-ft @ 2,100 rpm
REDLINE 6,500 rpm
WEIGHT TO POWER 14.1 lb/hp
TRANSMISSION 6-speed manual
AXLE/FINAL-DRIVE RATIO 4.35:1/2.98:1
SUSPENSION, FRONT; REAR Struts, coil springs, adj shocks, anti-roll bar; multilink, coil springs, adj shocks, anti-roll bar
STEERING RATIO 10.9:1
TURNS LOCK-TO-LOCK 2.1
BRAKES, F; R 12.3-in vented disc; 11.1-in disc, ABS
WHEELS 7.0 x 18-in cast-aluminum
TIRES 235/40R18 95Y Goodyear Eagle F1 Assymetric 2
TRACK, F/R 60.5/61.2 in
TURNING CIRCLE 37.8 ft
CURB WEIGHT 2,899 lb
WEIGHT DIST, F/R 61/39%
HEADROOM, F/R 37.5/36.8 in
LEGROOM, F/R 42.3/37.4 in
SHOULDER ROOM, F/R 56.9/55.0 in
CARGO VOLUME 14.7 cu ft
ACCELERATION TO MPH
0-30 2.5 sec
0-80 11.1
0-100 17.2
PASSING, 45-65 MPH 3.6
TOP-GEAR REVS @ 60 MPH 2,400 rpm
STABILITY/TRACTION CONTROL Yes/Yes
AIRBAGS 6: Dual front, front side, f/r curtain
BASIC WARRANTY 3 yrs/36,000 miles
POWERTRAIN WARRANTY 5 yrs/60,000 miles
ROADSIDE ASSISTANCE 3 yrs/36,000 miles
FUEL CAPACITY 12.4 gal
EPA CITY/HWY/COMB ECON 26/36/30 mpg
ENERGY CONS, CITY/HWY 130/94 kW-hrs/100 miles
RECOMMENDED FUEL Unleaded premium
Our Car
SERVICE LIFE 5 mo / 3,004 mi
PROBLEM AREAS None
MAINTENANCE COST $0
NORMAL-WEAR COST $0
RECALLS None

redpajama_set_name: RedPajamaCommonCrawl


We're looking for an active, non-smoking housesitter (couple preferred) who would enjoy caring for our loving, senior dog Jenny and our two cats, and living on our maple farm in the Berkshires from 3rd week of June to 3rd week of August while we do conservation work overseas. We're located in a very private setting off a dirt road and a car is required for the housesit. Extended family live nearby. Solar hot water, high speed internet. The farm is near the beautiful village of Shelburne Falls, Zoar Outdoor and Berkshire East Mountain Resort, MASS MOCA, and much more!
underway is a Verified Supporter of Housecarers.


When your customers complain about your stuff, you do everything you can to fix it. But how long does it take for that complaint to get to you in the first place? For huge companies like Nissan, it's even harder to gather all of the incoming complaints and get them to the right person to solve the issue.
In fact, according to Nissan Senior Manager of Customer Experience, Anne McGraw, one unhappy customer's Twitter rant persuaded someone about to buy a car to leave their dealership. She says with their new system of "Diagnostic Social Care," they've gotten much better at identifying problems, communicating them to the company, and getting results fast.
Watch her full presentation below.
Nissan: Diagnostic social care, presented by Anne McGraw from SocialMedia.org on Vimeo.
Download her presentation deck here.


text:
Summary of equipment maintenance and new capacity of caustic soda manufacturers in October
Caustic soda and liquid chlorine rise together
Analysis of domestic polypropylene market
Methanol price rise is limited
rolling bearing
Wake up the second spring of methanol futures
Haze ignites methanol
Dual support of environmental protection and Fundamentals
Soda ash: better troops and simpler administration to maintain industrial safety
The price of soda ash in China rose slightly in October
Sulfur rising
chromium car
Researchers Use a 3D Printer to Produce Fine Aerogel Structures
Behind the simple headline "Additive manufacturing of silica aerogels" - the article was published on July 20th in the renowned scientific journal Nature - a groundbreaking development is hidden. Silica aerogels are light, porous foams that provide excellent thermal insulation.
In practice, they are also known for their brittle behaviour, which is why they are usually reinforced with fibres or with organic or biopolymers for large-scale applications. Due to their brittle fracture behaviour, it is also not possible to saw or mill small pieces out of a larger aerogel block. Directly solidifying the gel in miniaturised moulds is also not reliably - which results in high scrap rates. This is why aerogels have hardly been usable for small-scale applications.
Stable, well-formed microstructures
The Empa team led by Shanyu Zhao, Gilberto Siqueira, Wim Malfait and Matthias Koebel have now succeeded in producing stable, well-shaped microstructures from silica aerogel by using a 3D printer. The printed structures can be as thin as a tenth of a millimeter. The thermal conductivity of the silica aerogel is just under 16 mW/(m*K) - only half that of polystyrene and even significantly less than that of a non-moving layer of air, 26 mW/(m*K). At the same time, the novel printed silica aerogel has even better mechanical properties and can even be drilled and milled. This opens up completely new possibilities for the post-processing of 3D printed aerogel mouldings.
With the method, for which a patent application has now been filed, it is possible to precisely adjust the flow and solidification properties of the silica ink from which the aerogel is later produced, so that both self-supporting structures and wafer-thin membranes can be printed. As an example of overhanging structures, the researchers printed leaves and blossoms of a lotus flower. The test object floats on the water surface due to the hydrophobic properties and low density of the silica aerogel - just like its natural model. The new technology also makes it possible for the first time to print complex 3D multi-material microstructures.
Insulation materials for microtechnology and medicine
The Climbing Koala 3D Printer and the Future of Manufacturing and Construction
What is Aerogel? Theory, Properties and Applications
Process and Application of Lightweight Structures
With such structures it is now comparatively trivial to thermally insulate even the smallest electronic components from each other. The researchers were able to demonstrate the thermal shielding of a temperature-sensitive component and the thermal management of a local "hot spot" in an impressive way. Another possible application is the shielding of heat sources inside medical implants, which should not exceed a surface temperature of 37 degrees in order to protect body tissue.
A functional aerogel membrane
3D printing allows multilayer/multi-material combinations to be produced much more reliably and reproducibly. Novel aerogel fine structures become feasible and open up new technical solutions, as a second application example shows: Using a printed aerogel membrane, the researchers constructed a "thermos-molecular" gas pump. This permeation pump manages without any moving parts at all and is also known to the technical community as a Knudsen pump, named after the Danish physicist Martin Knudsen. The principle of operation is based on the restricted gas transport in a network of nanoscale pores or one-dimensional channels of which the walls are hot at one end and cold at the other. The team built such a pump from aerogel, which was doped on one side with black manganese oxide nanoparticles. When this pump is placed under a light source, it becomes warm on the dark side and starts to pump gases or solvent vapours.
Air purification without moving parts
These applications show the possibilities of 3D printing in an impressive way: 3D printing turns the high-performance material aerogel into a construction material for functional membranes that can be quickly modified to suit a wide range of applications. The Knudsen pump, which is driven solely by sunlight, can do more than just pump: If the air is contaminated with a pollutant or an environmental toxin such as the solvent toluene, the air can circulate through the membrane several times and the pollutant is chemically broken down by a reaction catalyzed by the manganese oxide nanoparticles. Such sun-powered, autocatalytic solutions are particularly appealing in the field of air analysis and purification on a very small scale because of their simplicity and durability.
Empa researchers are now looking for industrial partners who want to integrate 3D-printed aerogel structures into new high-tech applications.
Prev: Theoretical Insights into Chemical Transformation of Heavy Oil Under High Temperatures
Theoretical Insights into Chemical Transformation o


text:
Contrary to the cookbook title, this cookbook *does not* install any client
application. It does however prepare the node in question to be accessible by
the BackupPC server and set some sane defaults for backing up the node.

For this cookbook to be of any use, you should first set up a BackupPC server
node using the [backuppc-server][] cookbook.

[backuppc-server]: http://community.opscode.com/cookbooks/backuppc-server

## Requirements

### Platforms

* Debian-family

### Dependencies

* sudo `~> 2.5.2`

## Attributes

See the [default][] attribute files for configuration variables and their
explanation.

[default]: attributes/default.rb

## Recipes

### Default

After setting the configuration variables, all that is left to do is to include
the default recipe:

```ruby
include_recipe 'backuppc-client::default'
```

Your BackupPC server will find the nodes depending on this cookbook and uses the
defined cookbook attributes to configure the backup strategy.

## TODO

* add unit and integration tests
* restrict rsync-only command through `authorized_keys` and custom shell script

## License and Author

Author:: Jean Mertz (<jean@mertz.fm>)

Copyright 2014, Kabisa ICT

Licensed under the MIT License (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://opensource.org/licenses/MIT

Unless required by applicable law or agreed to in writing, software distributed
under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
CONDITIONS OF ANY KIND, either express or implied. See the License for the
specific language governing permissions and limitations under the License.

redpajama_set_name: RedPajamaGithub


text:
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<ServiceCallout async="false" continueOnError="false" enabled="true" name="SC-RetrieveJWKSFromURI">
    <DisplayName>SC-RetrieveJWKSFromURI</DisplayName>
    <Properties/>
    <Response>jwksResponse</Response>
    <HTTPTargetConnection>
        <URL>https://{jwksHostname}/{jwksEndpoint}</URL>
    </HTTPTargetConnection>
</ServiceCallout>


text:
ATC Live agent Chris Meredith passes, aged 37
"A much-loved member of the live music community": friends and colleagues pay tribute to ATC Live agent and Neverworld Music Festival director Chris Meredith
By Anna Grace on 18 Sep 2019
Chris Meredith
Chris Meredith, agent at ATC Live and festival director at Neverworld Music Festival, has passed away at the age of 37.
Lee Denny, Neverworld founder says, "Chris had a rare and wonderful character. His unwavering dedication to supporting the projects, artists and music he loved was unmatched.
"Throughout our time together as friends and colleagues, and all the highs and lows that came with them, Chris could be relied upon to be gentle, supportive and kind in every interaction."
A much-loved member of the live music community, Meredith worked with artists including We Are Scientists, Sleeper, Fazerdaze and the Veils in his role at ATC Live.
"Chris had a rare and wonderful character. His unwavering dedication to supporting the projects, artists and music he loved was unmatched"
ATC Live's Alex Bruford says, "Chris joined us in 2015 and brought a wealth of knowledge to the company. As well as being a talented agent, he was a wonderful, kind, funny and generous man and a good friend to many across the industry. We will miss him deeply."
Previously, Meredith had spent time at Coda Agency and ITB, as well as working on various aspects of Nozstock: The Hidden Valley Festival, Red Rooster Festival and running his own promotions company.
Latitude festival's Ed Lilo says, "From co-promoting DIY shows in Brighton to being a top sounding board [and sometimes agent!] for me at Festival Republic, Chris was always a smart, funny and genuine human and I miss him tremendously. Sad times."
Paradigm's Alex Hardee adds, "Chris was a very lovely guy who still had a lot of friends at Coda ( I know we are called Paradigm now) – it has really hit some of them hard that he is now gone and at such a young age. Condolences to the family, he will be sorely missed."
Roots Manuva agent Marlon Burton joins ATC Live
Burton is tasked with developing the "urban/contemporary side" of the London-based booking agency, says MD Alex Bruford
ATC Live makes hires from Earth, UTA
The London-based agency has added Sleaford Mods, Girl Band and Romare to its roster with the hiring of Isla Angus, Sarah Besnard and Sinan Ors
Marketing exec Chris Loll joins Live Nation
Loll, formerly of IPG Mediabrands, heads up Live Nation Media & Sponsorship in the newly created position of COO
Guillaume Brevers and Graham Clews join ATC Live
Both new hires "embody the spirit of independent thinking we have here at ATC Live", says Alex Bruford, MD of the fast-growing UK agency
ATC Live announces new booking agents, ESNS plans
London-based booking agency ATC Live has started 2016 with the announcement of a number of new agents, its plans for Eurosonic Noorderslag (ESNS) and its festival roster for the year. Joining ATC Live in January are Clemence Renaut, Roxane Dumoulin and Chris Meredith. Renaut and Dumoulin join from Elastic Artists and bring to ATC Mac…
Richard Branson announces new US Virgin Fest
The festival, set to debut in 2019, will feature "diverse music acts, cutting-edge technological experiences … and a commitment to sustainability", says Branson


Would anyone, man or woman, ever want to be seen drinking this? For some reason I'm totally thinking about THIS right now.
I'm a chick who already drinks Michelob Ultra (which apparently has less calories and carbs) and I get made fun off enough for that.
I like the name of this beverage. It's cool to call it chick. Nice packaging and product name. It will be a very interesting product.
cute packaging, but can it get you to switch from what is already your favorite beer?
Something needs to be done about beer to get me to drink it, but it isn't the packaging or marketing. The horrible taste of beer makes me steer clear. I could do without the puke pink packaging.


text:
Half of coronavirus cases in Washington state are under the age of 40
The coronavirus is moving from older to younger residents in Washington state.
Half of the confirmed cases in Washington by early May are under the age of 40, marking a significant shift from the early outbreak of the virus when that age group accounted for just 33 percent of sick residents, according to a new study.
The researchers behind the work are urging health officials to increase awareness and safety efforts targeted toward younger Americans as states continue to reopen.
Even though young people are less likely to be hospitalized with COVID-19, they can still become seriously ill and their lifestyles put them at a greater risk of spreading the disease to others, Seattle epidemiologist Judith Malmgren, who led the study, told the Seattle Times.
"Younger people are the most likely to be socially active, they are the most likely to work in essential professions and have more contact with the public," Malmgren said.
The report, posted on the reprint server medRxiv, uses the state's publicly available health data to track the ages of cases between March 1 and May 3, showing the share of cases shifting to younger populations after the total number of infections peaked in late March.
The analysis doesn't delve into why cases have shifted toward younger patients. But Malmgren said anecdotally she's observed more younger people in her city out and about without facemasks.
Health officials in the state told the Seattle Times that the trends were the results of early awareness targeting older, vulnerable populations — as younger residents stayed home less often.
"The pattern in who's getting infected over time reflects people's behavior," Dr. Jeff Duchin, a health officer for Seattle & King County, told the paper.
← Scientists create virus that has potential to fight cancer
Seven people shot in Louisville during protests over death of Breonna Taylor →
18-year-old security guard fatally shot by deputies in California
Dad, two daughters and niece were not wearing seat belts in fatal car wreck
Texas homeowner strikes burglar 'in the face' with machete, cops say


text:
More Changes to UAE Residency Laws Expected, says Al Mulla
Further changes to the UAE's residency law are expected in the coming year, as the UAE cabinet begins the implementation of the 10-year residency visa law for expats, investors and businesspeople, according to the chairman of UAE law firm Baker McKenzie, Dr Habib Al Mulla.
In an opinion piece looking ahead to 2019, submitted to Arabian Business, Dr Habib Al Mulla said residency laws will likely be altered further in order to attract more foreign investors.
"We can only expect more initiatives to improve the UAE's status on all fronts, particularly when it comes to commercial law. And while the UAE has done much in this regard, I believe there is still room for improvement. So I predict a further relaxation of residency laws through minor alterations in order to make them more appealing, once the new regulations find their way into implementation," he said.
Al Mulla said he expects similar changes to the 100% foreign ownership laws, as they fail to offer regionally competitive incentives.
"The same would apply to foreign ownership laws. In my view, the current changes, although highly welcomed, remain insufficient in attracting serious and large foreign investments, particularly with the incentives that other countries in the region are offering," he said.
"Investors will demand, rightly so, further activities to be subject to the foreign ownership exemptions," he added.
The full ownership of companies based in the UAE is currently limited to free zones, which allow struggle to compete as their bestselling proposition is weakened, according to Al Mulla.
"Naturally, with more exemptions, free zones will feel the pressure and will struggle to compete unless they manage to change their modus operandi, although competition is healthy and can only benefit the economy," he said.
This year, investors, entrepreneurs and specialists working in fields of medicine, science or research in the UAE will be eligible for a five or 10-year residency visa depending on the size of their investment in the country.
Source: arabianbusiness.com


text:
Assassin's Creed Unity Special Edition
Action, Video Games
Strong violence, Online interactivity More information
The Special Edition includes:
Assassin's Creed® Unity game
1 additional single player mission for an extra 30 minutes of gameplay:
The Chemical Revolution: Antoine Laurent de Lavoisier is considered to be the "Father of Modern Chemistry". As a result of his efforts, he was able to create the formula for a poison bomb. Unfortunately he was taken before he could give it to you. Help him escape his kidnappers and recover the formula of the precious bomb.
Paris, 1789 - The French Revolution turns a once-magnificent city into a place of terror and chaos. Its cobblestone streets run red with the blood of commoners who dared to rise up against the oppressive aristocracy. As the nation tears itself apart, a young man named Arno will embark on an extraordinary journey to expose the true powers behind the Revolution. His pursuit will throw him into the middle of a ruthless struggle for the fate of a nation, and transform him into a true Master Assassin.
Introducing Assassin's Creed® Unity, the next-gen evolution of the blockbuster franchise powered by the all new Anvil engine. From the storming of the Bastille to the execution of King Louis XVI, experience the French Revolution as never before – and help the people of France carve an entirely new destiny.
A Unique Co-op Experience You Must Play To Believe
In addition to an epic single-player campaign, join with up to three friends online and experience the open world of 18th-century Paris. Pull ambitious heists and take part in unique narrative-driven missions designed exclusively for co-op play. Sabotage an execution. Protect an emperor. Assassinate a Templar agent. Victory won't be easy; you and your lethal band must rely on communication, coordination, and diverse skills to accomplish your missions, then vanish into the shadows.
A Ruthless New Hero for a Brutal World
Play as Arno, an entirely new breed of Assassin, and take down your prey with a range of new weapons such as the Phantom Blade, a hidden blade with crossbow capabilities.
Brand-New Parkour, Combat, Stealth Gameplay
Full motion control with new parkour mechanics for free running up, across, and down city walls and buildings.
A reinvented fighting system provides a richer combat experience based on skill, timing, and flow.
Enhanced stealth gameplay, including a new stealth mode, cover system, and crowd-manipulation techniques.
Deep Customization Mechanics to Craft Your Own Master Assassin
Craft a unique play style by choosing weapons, gear, outfits, and specialized skills. Mix and match from hundreds of possible combinations and build your stealth, fighting, and navigation abilities from a new, expansive skill tree.
Discover Revolutionary Paris,Brought to Life as Never Before
Carve through the stunning full-scale open world city, a feat only made possible through the power of an all-new game engine. Explore detailed building interiors and discover secret catacombs and sewers. Embark on ancestral missions, treasure hunts, murder mysteries, contracts, and more. The city is packed full of activities that will captivate for hours. Witness the chaos of the French Revolution firsthand and become immersed in the realistic, systemic crowds of up to 5,000 AI-driven characters.
Assassin's Creed: Syndicate Special Edition
Far Cry Primal - Special Edition


If you are a leaseholder, resident, or employee of a commercial unit at the Spectrum / Aurora Buildings please come along to the Annual General Meeting of Ixia (East Road) Management Company Limited.
Ixia is the 'right to manage' company made up of leaseholders of the development who volunteer to manage the development. The meeting provides you with the opportunity to provide input into the management of the development, meet the Management Company Rendall & Rittner that handles the day-to-day operations of the development, and help make the development a better place to live and work.
Please register your attendance HERE so that we have an idea on numbers. However, feel free to drop in on the day as the more people the better!
If you have any items you would like to be considered for the AGM agenda please email them to ixialondon@gmail.com by 12 noon on 27 October 2018.
To see documents relevant to the AGM, log-in to the 'members area' of the Spectrum Buildings website, where documents and the agenda will be posted closer to the date of the meeting.
Please remember that only leaseholders have a formal vote at the meeting, however, anyone with a stake in the development is happy to attend. The venue is a short walk from the development so please do try to attend.
Join us for a little clean up of our courtyard and to meet your neighbours.
Some of us have made great friends in the buildings, but some neighbours we might not even know yet.
We want to change that. Together we'll clean up the courtyard and make it more of a place we're happy to come back to and have our children play in.
Once we're done cleaning and gardening, we'll bring out drinksand snacks for everyone to share.
We'll meet 11am to about 1pm, while it's still nice and sunny in the courtyard.


The following companies and/or organizations are participants in the new Milton Historical Society "Corporate Membership Program" for the current year ending December 31st.
As Corporate members, your organization and employees will have the opportunity to participate in the preservation of the history of the Town of Milton and surrounding area, as well as learning more about the origins of our Town. Your company information will be added to our web site and to our quarterly newsletter.
If you have sufficient information and wish to have your membership processed, please complete the online membership form , or print out the PDF form and forward along with your cheque along with your company contact information to the Milton Historical Society, 16 James Street, Milton, Ont. L9T 2P4.
Should you wish more information please feel free to contact us at 905-875-4156 or info@miltonhistoricalsociety.ca.


As fairly-new web technologies, Service Workers, Web Workers and WebSockets all started, stalled, and then sort of made a resurgence. And so I find myself somewhat confused by exactly what each does, what the differences between them are, and what purpose each ideally serves.
Getting Things Done with WebSockets and Web Workers is an online chapter from Learning HTML5 Game Programming.
Ajax vs. Web sockets vs. Web Workers is a StackOverflow article.
…but neither compares the three I was curious about… So I decided to get to know them all a little better and document my findings here (so I could come back and remind myself again later…).
This article will not cover anything in-depth, no set-up or use instructions, and likely very little, if any, actual code; I will link to plenty of resources for all of that, but this is just to get to "know" each of these new web technologies.
Background service that handles network requests. Ideal for dealing with offline situations and background syncs or push notifications. Cannot directly interact with the DOM. Communication must go through the Service Worker's postMessage method.
Mimics multithreading, allowing intensive scripts to be run in the background so they do not block other scripts from running. Ideal for keeping your UI responsive while also performing processor-intensive functions. Cannot directly interact with the DOM. Communication must go through the Web Worker's postMessage method.
Creates an open connection between a client and a server, allowing persistent two-way communication over a single connection. Ideal for any situation where you currently use long-polling such as chat apps, online games, or sports tickers. Can directly interact with the DOM. Communication is handled through the WebSocket's send method.
Service Workers are pretty perfect for creating offline-first web apps. They let you interact with the server when you can (to fetch new data from the server, or push updated info back to the server), so your app can work regardless of your user's connectivity.
For example, an email client could fetch emails when the app loads, then, if the user loses connectivity for a brief period, the app could still continue to register read/unread and deleted states and store new emails to send until connectivity is restored, then send those updates back to the server via a Service Worker. To the user, all the time they were offline, the app continued to work, so they "got stuff done", and your app just did its job, by collecting changes and updating the server as soon as it could.
While Service Workers cannot directly interact with the DOM, your main JS code can do that based on the messages you receive back from a Service Worker. Service workers also stop when not being used and restart when needed, so there is no persistent "state"; you would need to rely on some form of local storage for such persistence. It is important to remember that a Service Worker's life cycle is completely separate from your webpage.
From above, HTML5 Rocks' introduction to Service Workers.
Also from above, Is Service Worker Ready?, maintained by Jake Archibald, is the go-to site for checking the implementation and support in browsers.
The MDN Service Worker API page, provides all the specs and functionality.
Using ServiceWorker in Chrome today is a nice walk-through on basic usage of Service Worker.
YouTube video The ServiceWorker: The network layer is yours to own.
Note that the Service Worker W3 spec is still a Working Draft.
Workers utilize thread-like message passing to achieve parallelism.
Web Workers are pretty perfect for any web app that has intense functions to perform. They let you push the intense functions into a background thread so your main JS can keep on rocking, like maybe setting up event listeners and other UI interactions. Then, when the intense functions are done, they report back with their results, letting the main JS update the web app.
For example, a site that fetches and displays data in a series of dynamic charts could have each chart fetch its own data via a separate Web Worker. While the Web Workers are fetching, processing, and calculating their data, the main JS could be setting up menus, event listeners, initializing date pickers and custom UI elements, etc. And when each Web Worker is done with its process, it can report back to the main JS with its resulting data to be used to create its respective chart.
While Web Workers cannot directly interact with the DOM, your main JS code can do that based on the messages you receive back from a Web Worker. And as they are completely separate threads, Web Worker code must exist in a separate file and does not have access to your main JS. Workers can also spawn subworkers, to create additional background threads.
Support for Web Workers is quite good, with only IE < 10 and Android < 4.4 deserving any real consideration.
From above, HTML5 Rocks' introduction to Web Workers.
Also from above, Can I Use page for Web Workers, for checking browser support.
The MDN Web Worker API page, provides all the specs and functionality.
Note that the Web Worker W3 spec is still a Working Draft.
There is an [sic] persistent connection between the client and the server and both parties can start sending data at any time.
WebSockets are pretty perfect for any web app that needs to communicate frequently with a server, and could benefit from the server being able to communicate directly with the client.
So, with WebSockets we finally can directly affect the DOM and, as they are part of the main thread, WebSockets do have access to your main JS.
Support for WebSockets is quite good, with only IE < 10 and Android < 4.4 deserving any real consideration.
From above, HTML5 Rocks' introduction to WebSockets.
Also from above, Can I Use page for WebSockets, for checking browser support.
The MDN WebSockets API page, provides all the specs and functionality.
Note that the WebSockets W3 spec is still a Working Draft.
So, while WebSockets and Service Workers kind of overlap, both being used for client-server communications, WebSockets would be used more for continuous communication so both the client and the server can send messages to each other without having to create new connections, and Service Workers would be used more for one-off client-server communications like syncing an app and the database after the app was offline for some time, like a burst that can then be dropped when the sync is completed.
And Web Workers are something completely different, allowing processor-intensive functions to run in a separate, background thread, while allowing the main JS to run and the UI to setup and operate more smoothly while those intensive functions are still running in the background.
Thanks for the post and the links. Very useful.
Very useful post. Simple amazing! Thanks!!
Great post, but i am still not entirely clear on the difference between Web Workers and Service Workers? they both appear to be the same in terms of functionality? Would someone elaborate further please? thank you.
Hey, Mark, thanks for the question.
Yes, Web Workers and Service Workers do appear to be pretty similar: both work in the background, mimicking multi-threading; both communicate back to your main JS via a postMessage; and neither can directly interact with the DOM. And it is possible that they can both handle some of the same tasks.
Web Workers are more for heavy JS tasks, the kind of stuff that might greatly slow, or even completely block, your site's UI. Stuff like compiling or crunching a bunch of data, generating resource-intensive charts or diagrams, etc. This can all be pushed off to a Web Worker, while the main JS goes about some other task(s), and when the Web Worker is done, it will send the completed work back to the main JS to do whatever with.
I hope this helps clear things up at least a little. But the best way to get to know them each better, is by digging in and playing with them all to find out what works, what doesn't, and what makes more sense in various situations.
Thanks for reading, and for the question!
Terrific explanation and clarified a few vital points for me.
Awesome Aaron, pretty neat explanation on workers.
Best explanation to be found anywhere of the differing functionalities! Thanks for clarifying!
Thanks for the publication. Kudos!!!
I'm reading this awesome article at 3 pm and for future readers who want night theme.
localStorage is not available in service workers..
Thanks, alex, duly noted, and removed from the article!
One suggestion tho, is that Service Workers, are actually a "type" of Web Workers. They're Web Workers dedicated to syncing, pushing and offline stuff.
Hey, Remy, thanks for the note.
A very timely explanation for me. Well done.
One of best articles I have ever come across. You cleared my all doubts in a single blog.
Thank you so much for pointing out the differences and explaining each of them so clearly.


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21. Jan 2022 Cazenovia CSD > News > *District News > Introducing Our New Cazenovia Faculty
Introducing Our New Cazenovia Faculty
Written by on September 30, 2021 . Posted in *District News, ES News, HS News, MS News, Uncategorized
Cazenovia CSD Welcomes Kyle Prenoveau, New K-4 PE Teacher
Please join Cazenovia Central School District in welcoming new elementary Physical Education Teacher Kyle Prenoveau.
Mr. Prenoveau has been teaching for two years. Prior to joining Cazenovia CSD, Mr. Prenoveau taught K-4 Elementary Physical Education (PE) in the West Genesee School District. Mr. Prenoveau earned his Bachelor of Science in Physical Education from SUNY Cortland.
When not teaching, Mr. Prenoveau can be found playing and coaching sports. He also enjoys listening to live music, hiking, skiing, and attending sporting events as a fan.
Cazenovia CSD Welcomes HS Business & Computer Teacher Ken Hammond
Please join Cazenovia Central School District in welcoming new high school Business and Computer Teacher Ken Hammond.
Mr. Hammond will be entering his second year of teaching. Prior to Cazenovia, Mr. Hammond taught one year at DeRuyter Central Schools in the Business and Computer Science program.
Mr. Hammond became a teacher after several years in Sport Event Production. He earned his Bachelor of Arts degree in Sports Management from SUNY Cortland and holds a Master of Science in Education degree in CTE with a focus on Business and Marketing from SUNY Oswego. He has spent the last 11 years working for IRONMAN/World Triathlon Corp. as a Race Director for several IRONMAN 70.3 events and continues to do so.
Mr. Hammond is a proud father of a son who is entering the first grade this fall and has a wife who has worked in education for the past 12 years as an English Teacher in the Fayetteville-Manlius School District. He is an avid cyclist and a person who enjoys all sports.
Cazenovia CSD Welcomes Spanish Teacher Laura Shippee
Please join Cazenovia Central School District in welcoming new Spanish teacher Laura Shippee to the sixth and seventh grades.
Sra. Shippee has spent the last twenty years teaching Spanish. She earned her master's degree in Secondary Education from SUNY Oswego as well as a bachelor's degree in Public Justice and Spanish. She studied at the University of Barcelona, Spain and has travelled to Mexico and the Dominican Republic.
Growing up in Clifton Park, NY, Sra. Shippee currently resides in Baldwinsville where she enjoys spending time with her three children (ages 6, 11 and 14).
Cazenovia CSD Welcomes Middle School Physical Education Teacher Christopher Bubble
Please join us in welcoming new physical education teacher Christopher Bubble to Cazenovia Central School District.
Mr. Bubble has coached basketball for 15 years and has experience coaching football, baseball and softball and plans to continue his coaching career at Cazenovia. He said he looks forward to teaching, mentoring and being a resource for all young people.
Mr. Bubble has been a physical education teacher for 13 years, teaching elementary, middle and high school P.E. at Newfield Central School District and also served as Dean of Students prior to joining us at Cazenovia.
"I'm passionate about teaching students to become physically active for a lifetime and challenging them to maximize their athletic potential," he said.
Growing up in the Ithaca area, he earned his bachelor's degree in Physical Education Teaching from Ithaca College and his master's degree in Physical Education (Coaching Pedagogy) from SUNY Cortland. Currently, he is pursuing a CAS in School Building and School District Leadership from SUNY Cortland.
Mr. Bubble lives in Cazenovia with his wife Tara and their two children Colton and Hayden.
Cazenovia CSD Welcomes new Registered Nurse Renee Fuller
Please join us in welcoming new registered nurse Renee Fuller to Cazenovia Central School District.
Mrs. Fuller has been a registered nurse (practicing in pediatrics), for the past eight years, the last four of which she served as an elementary school nurse in the Oneida City School District.
Mrs. Fuller first earned her Bachelor of Science degree in Nutrition from Cornell University before pursuing her nursing degree from Crouse Hospital College of Nursing. She said she is excited to bring her passion for helping people to the Cazenovia students and community.
Mrs. Fuller enjoys staying active and exploring the outdoors with her husband and two young boys, one of whom will be joining her at Burton Street for his first year in school!
Cazenovia CSD Welcomes new Fifth Grade Teacher Kaelee Cleary
Please join us in welcoming new fifth grade teacher Kaelee Cleary to Cazenovia Central School District.
Ms. Cleary is from Waterville, New York, where she grew up on a small family farm. She attended Mohawk Valley Community College, where she received her Associate's degree in Childhood Education with a concentration in English. She then transferred to SUNY Cortland where she received her Bachelor's degree in Early Childhood/Childhood Education with a concentration in mathematics. Ms. Cleary is currently attending SUNY Brockport to complete her Master's degree in TESOL (Teaching English to Speakers of Other Languages). As of now, she is certified to teach birth through sixth grade.
Ms. Cleary has been substitute teaching since her freshman year in college. She has worked in a variety of districts, including Waterville, Sauquoit, Brookfield, and McGraw. She has been a part of Cazenovia Central School District for one year. Last fall, she student taught at Burton Street Elementary in second grade with Pam Rightmyre. She then began substituting for the district and completed a long-term placement in third grade. In her free time, Ms. Cleary enjoys spending time outside hiking, kayaking, camping, and traveling. She also loves to cook and spend time with her family (especially her niece)! Ms. Cleary said she is incredibly excited to become a member of the Cazenovia community and family. She is looking forward to working with students, families, and the faculty here at Cazenovia!
Cazenovia CSD Welcomes new MS Art Teacher Julia Macreery
Please join Cazenovia Central School District in welcoming new middle school art teacher Julia Macreery.
Mrs. Macreery is a graduate of Fayetteville-Manlius High School, SUNY Geneseo with a Bachelor's in Art History and Studio Art, and Syracuse University with a Master's in Art Education.
Prior to Cazenovia, she worked as an art teacher in the Syracuse City and ESM School Districts, as well as at the YMCA and Bright Beginnings Preschool. Aside from art and teaching, Mrs. Macreery enjoys scouting, camping, and spending time with her family. She said she is very excited to start teaching art to the students in Cazenovia!
Cazenovia CSD Welcomes Katie Carkey, K/1 Special Education Teacher
Please join us in welcoming Katie Carkey to Burton Street Elementary as the new K/1 Special Education Teacher.
Previously, Mrs. Carkey spent 13 years teaching at Jowonio School (an inclusive preschool in Syracuse). Katie earned her undergraduate degree from Utica College in Psychology Child Life and her Master's degree from Syracuse University in Early Childhood and Special Education.
When she's not teaching, Mrs. Carkey can be found exploring parks and going on adventures with her husband, 3-year-old daughter, and Great Dane. She also loves Syracuse basketball and trying out new recipes in the kitchen.
She said she's super excited to join the Burton Street team and can't wait to get to know all the teachers and students.
Cazenovia CSD Welcomes ENL Teacher Dana Cole
Please welcome Ms. Dana Cole to the Cazenovia Central School District as an English as a New Language (ENL) Teacher in the middle school and high school.
Ms. Cole, who has been teaching for seven years, previously taught ENL in the DeRuyter Central School District, working with all English Language Learners district wide.
Ms. Cole earned her Bachelor of Arts degrees in Teaching English as a Second Language and Spanish from SUNY Cortland. She also holds a Master of Science in Education degree in Literacy Education (Birth-Grade 6 and Grades 5-12) from SUNY Cortland.
When not teaching, Ms. Cole can be found tutoring migrant students in the local area or playing piano. In her free time, Ms. Cole enjoys spending time with her husband and dog, camping, hiking, and traveling.
Cazenovia CSD Welcomes Miss Samantha Kio, New School Psychologist Intern
Please welcome Miss Samantha Kio as Cazenovia Central School's new School Psychologist Intern.
Miss Kio is a graduate student at SUNY Oswego where she is completing the requirements for her M.S. in School Psychology and her Certificate of Advanced Study (C.A.S.) in trauma studies. She earned her undergraduate degree at SUNY Oneonta where she received a B.S. in Psychology.
When Miss Kio is not working in the district or on her graduate degree, she can be found reading, playing music, or spending time with her twin sister. She also enjoys swimming during the warmer months of the year and skiing or snowboarding during the cold months. Her favorite football team is the Buffalo Bills.
Cazenovia CSD Welcomes Seventh Grade Math Teacher Connor Carroll
Please join us in welcoming Mr. Connor Carroll to the middle school as the seventh-grade math teacher. Mr. Carroll earned his Bachelor's in Mathematics with a minor in Education Studies from Ithaca College. He is currently certified for grades five through nine in mathematics and has spent the last several years teaching Geometry and Spanish at Christian Brothers Academy in Syracuse.
Mr. Carroll is a graduate of Cazenovia Central School District and has been an assistant coach in the district for the Boys' Varsity Cross Country team the last three years. He also enjoys coaching teams outside of the district in high school esports and outdoor track.
Mr. Carroll said he became a teacher because of the experiences he had while attending CCS. His mantra is to never stop learning because his students teach him while he is teaching them.
In his free time, Mr. Carroll competes in esports and spends time with family. He is thrilled to be returning to Cazenovia Central Schools in his new role.
Cazenovia CSD Welcomes Physics Teacher Jayson Pritchard
Please join us in welcoming Mr. Jayson Pritchard as the new physics teacher at Cazenovia.
Pritchard currently resides in Baldwinsville but grew up in the Rochester area. He earned a BFA in Theatre Design & Technology with minors in Math and Physics from Otterbein University near Columbus, OH. He earned an MSed in Inclusive Physics Education at The College at Brockport, near Rochester, NY.
Pritchard has worked all over the United States and Europe as theatre technician prior to becoming a teacher. He is excited to bring his technical theatre expertise to the Cazenovia CSD community.
This year, he will serve as a co-advisor to the HS Drama Club and Technical Director for the Spring Musical. Mr Pritchard is very excited to journey through the world of physics with his students this year in both AP and Regents Physics. When he is not teaching, Mr. Pritchard enjoys spending time at home with his cats. He enjoys reading and occasionally playing video games.