text:
\section{Introduction}
International telecommunications union (ITU) has reached the consensus that the next-generation mobile communications will realize the goals of 1000-fold system
capacity, 100-fold energy efficiency, and 10-fold
lower latency \cite{G1,G2}. To fullfill this explosive demand of capacity, millimeter-wave (mmWave) communication with the large transmission bandwidth is usually considered to support the high-capacity backhaul/fronthaul links between phantom-cell base stations (BSs) and macro-cell BSs \cite{R3}. A typical heterogeneous network (HetNet) can be illustrated in Fig. 1 \cite{bkh}. However, mmWave communication usually suffers from the severe path loss. Traditional fully-digital precoding with massive antennas can be used to mitigate the severe path loss, but  at the cost of high power consumption and hardware cost \cite{ref_plus_5,R1,R2,R5}. To combat this issue, hybrid MIMO architecture with the much lower number of radio frequency (RF) chains than that of antennas are employed with reasonable cost and power consumption \cite{ref_plus_9,ref_plus_10,R4,R6}. Owing to the frequency flat RF precoder/combiner with constant-modulus constraint but the practical frequency selective fading mmWave channels, hybrid analog/digital precoding design can be challenging.
\begin{figure}[htb]
	\centering
	\includegraphics[width=0.7\columnwidth, keepaspectratio]{backhaul0.eps}
	\caption{MmWave FD-MIMO based backhaul/fronthaul in HetNet.}
\end{figure}

Most prior mmWave hybrid precoding techniques are based on narrowband mmWave channels \cite{OMP,mao}. Specifically, a compressive sensing (CS)-based
hybrid precoding has been proposed in \cite{OMP}, where the channel sparsity is ingeniously exploited to design hybrid precoding with the aid of orthogonal matching pursuit (OMP) algorithm. To improve bit-error-rate (BER), an over-sampling codebook-based hybrid minimum sum-mean-square-error precoding is designed \cite{mao}. However in practical scenario, wideband scenario like OFDM is adopted more often \cite{lim_feedback,170825,fre_flat}. To be
specific, an insightful wideband hybrid precoder based on limited-feedback codebook has been proposed \cite{lim_feedback}. By exploiting the channel correlation information among different subcarriers, a wideband hybrid precoding is proposed not only for fully-connected structure, but also extended to the partially-connected ones \cite{170825}. Nevertheless, \cite{lim_feedback} fails to give the specific hybrid combiner at the receiver, and \cite{170825} assumes the unpractical fully-digital MIMO at the receiver. Finally, \cite{fre_flat} has theoretically shown the optimality of frequency flat precoding by proving that dominant subspaces of the frequency domain channel matrices of different subcarriers are equivalent. However, this conclusion is based on purely sparse channels with discrete angles of arrival (AoA) and angles of departure (AoD), and the practical precoder/combiner solution is not provided.

In this paper, we propose a principle component analysis (PCA) based wideband hybrid precoding scheme, which can efficiently support the mmWave FD-MIMO based backhaul/fronthaul links. To be specific, we propose the optimal PCA-based analog precoder scheme, where the low-dimensional signal space of frequency-flat RF precoder can be abstracted from the high-dimensional signal space of optimal frequency-selective precoders. Besides, the optimality of the proposed PCA-based hybrid precoding design is theoretically proven and verified. Moreover, we propose corresponding optimal weighted-PCA-based analog combiner design by extracting from fully-digital MMSE combiners. Furthermore, with the use of MMSE and equalization at digital combiner, the BER performance is improved. Simulation results show that our proposed precoding scheme have better spectral efficiency (SE) and BER performance compared to the conventional scheme.

\textsl{Notations}: Following notations are used throughout this paper. $\mathbf{A}$ is a matrix, $\mathbf{a}$ is a vector, and $a$ is a scalar. Conjugate transpose and transpose of $\mathbf{A}$ are $\mathbf{A}^H$ and $\mathbf{A}^T$, respectively. The $(i,j)$th entry of $\mathbf{A}$ is $[\mathbf{A}]_{i,j}$, and $[\mathbf{A}]_{i,:}$ ($[\mathbf{A}]_{:,j}$) denotes the $i$th row ($j$th column) of $\mathbf{A}$. Frobenius norm is denoted by $||\cdot||_F$. $|\mathbf{A}|$, $|\mathbf{a}|$, and $|a|$ are the determinant of a square matrix $\mathbf{A}$, $\ell_2$-norm of a vector $\mathbf{a}$, and modulus of a number $a$, respectively. The $i$th largest singular value of a matrix $\mathbf{A}$ is defined as $\lambda_i(\mathbf{A})$. Finally, $\mathfrak{R}\{\mathbf{A}\}$ means to keep the real part of a complex matrix $\mathbf{A}$. Additionally,
$\text{blkdiag}(\mathbf{a}_1,\cdots,\mathbf{a}_K)$ is a block diagonal matrix with $\mathbf{a}_i$ ($1\leq i\leq K$) on its diagonal blocks.

\section{System Model}
We consider an mmWave FD-MIMO system
where both the transmitter and receiver employ the uniform planar array (UPA), and OFDM is adopted to combat the frequency-selective fading in backhaul/fronthaul channels. The transmitter is equipped with $N_t=N_t^v\times N_t^h$ antennas and $N_t^{\rm RF}\ll N_t$ chains, where $N_t^v$ and $N_t^h$ are the numbers of vertical and horizontal transmit antennas, respectively. The receiver is equipped with $N_r=N_r^v\times N_r^h$ antennas and $N_r^{\rm RF}\ll N_r$ RF chains, where $N_r^v$ and $N_r^h$ are the numbers of vertical and horizontal receive antennas, respectively. Additionally, there are $N_s$ streams transmitting in the system. We consider the downlink transmission and the received symbols at the receiver can be written as \cite{OMP}
\begin{equation}\label{rcv_sig}
\mathbf{r}[k]=(\mathbf{W}_{\rm RF}\mathbf{W}_{\rm BB}[k])^H(\mathbf{H}[k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]\mathbf{x}[k]+\mathbf{n}[k]),
\end{equation}
where $1\leq k\leq K$ with $K$ being the number of subcarriers, $\mathbf{F}_{\rm BB}[k]\in\mathbb{C}^{N_t^{\rm RF}\times N_s}$, $\mathbf{F}_{\rm RF}\in\mathbb{C}^{N_t\times N_t^{\rm RF}}$, $\mathbf{W}_{\rm BB}[k]\in\mathbb{C}^{N_r^{\rm RF}\times N_s}$, $\mathbf{W}_{\rm RF}\in\mathbb{C}^{N_r\times N_r^{\rm RF}}$, $\mathbf{H}[k]\in\mathbb{C}^{N_r\times N_t}$, $\mathbf{x}[k]\in\mathbb{C}^{N_s\times 1}$, and $\mathbf{n}[k]\in\mathbb{C}^{N_r\times 1}$ are the digital precoder, analog precoder, digital combiner, analog combiner, channel matrix, transmitted signal, and noise associated with the $k$th subcarrier, respectively. Noise $\mathbf{n}[k]$ satisfies $\mathbf{n}[k]\sim \mathcal{CN}(0,\sigma_n^2)$ and transmitted signal $\mathbf{x}[k]$ satisfies $\mathbb{E}[\mathbf{x}[k]\mathbf{x}^H[k]]=\frac{P}{KN_s}$, where $P$ is the average total transmit power.

The frequency-domain channel $\mathbf{H}[k]$ can be expressed as $\mathbf{H}[k]=\sum_{d=0}^{D-1}\mathbf{H}_d[d]e^{-j\frac{2\pi k}{K}d}$ \cite{lim_feedback}, where $D$ is the maximum delay spread of the discretized channels, and $\mathbf{H}_d[d]\in\mathbb{C}^{N_r\times N_t}$ is the delay-$d$ channel matrix. We consider the clustered channel model \cite{OMP}, where the channel is composed by $N_{\rm cl}$ clusters of multipaths with $N_{\rm ray}$ rays in each cluster. Thus the delay-$d$ channel matrix can be written as
\begin{equation}\label{H_d}
  \mathbf{H}_d[d]\!\!=\!\!\sum\nolimits_{i=1}^{N_{\rm cl}}\!\sum\nolimits_{l=1}^{N_{\rm ray}}\!\!p_{i,l}^d[d]\mathbf{a}_r(\phi^r_{i,l},\theta^r_{i,l})\mathbf{a}_t^H(\phi^t_{i,l},\theta^t_{i,l}),
\end{equation}
where $p_{i,l}^d[d]=\sqrt{N_tN_r/(N_{\rm cl}N_{\rm ray})}\alpha_{i,l}p(dT_s-\tau_{i,l})$ is the delay-domain channel coefficient, $\tau _{i,l}$,  $\alpha _{i,l}$, and $p(\tau)$ are the delay, the complex path gain, and the pulse shaping filter for $T_s$-spaced signaling, respectively. Thus the relationship between the frequency-domain channel coefficiency and the delay-domain channel coefficiency is $p_{i,l}[k]=\sum_{d=0}^{D-1}p_{i,l}[d]\exp(-j2\pi kd/K)$. In (\ref{H_d}), $\mathbf{a}_t(\phi^t_{i,l},\theta^t_{i,l})$ and $\mathbf{a}_r(\phi^r_{i,l},\theta^r_{i,l})$ are the steering vectors of the $l$th path in the $i$th cluster at the transmitter and receiver, respectively. In the steering vectors, $\phi^t_{i,l}$ and $\theta^t_{i,l}$ are the azimuth and elevation angles of the $l$th ray in the $i$th cluster for AoDs, and $\phi^r_{i,l}$ and $\theta^r_{i,l}$ are the azimuth and elevation angles of the $l$th ray in the $i$th cluster for AoAs. Therefore, the transmit steering vectors for the UPA at the transmitter can be expressed as $\mathbf{a}_t(\phi^t_{i,l},\theta^t_{i,l})=
[1\ \ \ \cdots \ \ \ e^{-j2\pi(m\frac{d_h}{\lambda}\sin(\theta ^t_{i,l})\cos(\phi ^t_{i,l})+n\frac{d_v}{\lambda}\sin(\phi ^t_{i,l}))} \ \ \
\cdots \\e^{-j2\pi((N_t^h-1)\frac{d_h}{\lambda}\sin(\theta ^t_{i,l})\cos(\phi ^t_{i,l})+(N_t^v-1)\frac{d_v}{\lambda}\sin(\phi ^t_{i,l}))}]^T/\sqrt{N_t}$ \cite{OMP},
where $\lambda$ is the carrier wavelength, and $d_v$ and $d_h$ are the distances between adjacent antenna elements in vertical and horizontal direction, respectively. Similarly, we can also obtain $\mathbf{a}_r(\phi ^r_{i,l},\theta^r_{i,l})$ with the same form.

Assuming the Gaussian channels, the achieved SE can be expressed as \cite{lim_feedback}
\begin{equation}
\begin{aligned}
R=\tfrac{1}{K}&\sum\nolimits_{k=1}^{K}\log_2|\mathbf{I}+
\tfrac{\rho}{N_s}\mathbf{R}_n^{-1}[k]\mathbf{W}_{\rm BB}^H[k]\mathbf{W}_{\rm RF}^H
\mathbf{H}[k]
\\&\times\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]\mathbf{F}_{\rm BB}^H[k]\mathbf{F}_{\rm RF}^H\mathbf{H}^H[k]
\mathbf{W}_{\rm RF}\mathbf{W}_{\rm BB}[k]|,
\end{aligned}
\end{equation}
where $\mathbf{R}_n[k]=\sigma_n^2\mathbf{W}_{\rm BB}^H[k]\mathbf{W}_{\rm RF}^H
\mathbf{W}_{\rm RF}\mathbf{W}_{\rm BB}[k]$ and $\rho=\frac{P}{K\sigma_n^2}$ is the signal-to-noise ratio (SNR). It is worthy to point out that our work is different from the previous work \cite{170825} with the hybrid precoder considered at the transmitter but fully-digital combiner assumed at the receiver. In this paper, we consider the hybrid MIMO architecture at both the transmitter and receiver. Our goal is to design the hybrid precoder and combiner that maximizes the SE. However, it requires to jointly optimize $R$ over variables ($\mathbf{F}_{\rm RF}$,$\{\mathbf{F}_{\rm BB}[k]\}_{k=1}^K$,$\mathbf{W}_{\rm RF}$,$\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$) simultaneously, which is challenging. In the following sections, we will decouple the design of precoder and combiner to solve this intractable problem.

\section{Hybrid Precoder Design at Transmitter}
In this section, we discuss the design of the hybrid precoder/combiner for wideband mmWave MIMO backhaul/fronthaul channels. Our goal is to design the optimal frequency-flat RF precoder (combiner) from the optimal fully-digital precoder (combiner) for frequency-selective channels.
\subsection{Digital Precoder Design}
We first design the digital precoder by fixing the RF precoder. Specifically, we design the precoder to maximize the mutual information of the signalling as the following optimization problem
\begin{equation}
\begin{aligned}\label{opt}
\max\limits_{\mathbf{F}_{\rm RF},\mathbf{F}_{\rm BB}}&\!\!\sum\nolimits_{k=1}^{K}\log_2\!|\mathbf{I}\!+\!\tfrac{1}{\sigma_n^2}\mathbf{H}[k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]
\mathbf{F}_{\rm BB}^H\![k]\mathbf{F}_{\rm RF}^H\mathbf{H}^H\![k]|
\\\text{s.t. }&\mathbf{F}_{\rm RF}\in\mathcal{F}_{\rm RF},\sum\nolimits_{k=1}^K||\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]||_F^2=KN_s,
\end{aligned}
\end{equation}
where $\mathcal{F}_{\rm RF}$ is a set of feasible RF precoder satisfying constant-modulus constraint. The joint optimization of $\mathbf{F}_{\rm RF}$ and $\{\mathbf{F}_{\rm BB}[k]\}_{k=1}^K$ in (\ref{opt}) can still be difficult due to the coupling between the baseband and RF precoders \cite{lim_feedback}. Therefore, we consider $\mathbf{\widetilde{F}}_{\rm BB}[k]=(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{\frac{1}{2}}\mathbf{F}_{\rm BB}[k]$ to be the equivalent baseband precoder, and
the optimization problem (\ref{opt}) is equivalent to \begin{equation}
\begin{aligned}\label{opt_RF}
\max\limits_{\mathbf{F}_{\rm RF},\mathbf{\widetilde{F}}_{\rm BB}}&\sum\nolimits_{k=1}^{K}\log_2|\mathbf{I}+\tfrac{1}{\sigma_{\rm n}^2}
\mathbf{H}[k]\mathbf{F}_{\rm RF}(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}
\\&\times\mathbf{\widetilde{F}}_{\rm BB}[k]\mathbf{\widetilde{F}}_{\rm BB}^H[k](\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}\mathbf{F}_{\rm RF}^H\mathbf{H}^H[k]|
\\\text{s.t. }&\mathbf{F}_{\rm RF}\in\mathcal{F}_{\rm RF},\sum\nolimits_{k=1}^K||\mathbf{\widetilde{F}}_{\rm BB}[k]||_F^2=KN_s.
\end{aligned}
\end{equation}

For the optimization problem (\ref{opt_RF}), we first consider the optimal solution of $\{\mathbf{\widetilde{F}}_{\rm BB}[k]\}_{k=1}^K$. Specifically, consider the singular value decomposition (SVD) of $\mathbf{H}[k]$ associated with the $k$th subcarrier as $\mathbf{H}[k]=\mathbf{U}[k]\mathbf{\Sigma}[k]\mathbf{V}^H[k]$, and the SVD of the matrix $\mathbf{\Sigma}[k]\mathbf{V}^H[k]\mathbf{F}_{\rm RF}(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-1/2}=\mathbf{\widetilde{U}}[k]\mathbf{\widetilde{\Sigma}}[k]
\mathbf{\widetilde{V}}^H[k]$. Therefore, the optimal $\mathbf{\widetilde{F}}_{\rm BB}[k]=[\mathbf{\widetilde{V}}[k]]_{:,1:N_s}\mathbf{\Lambda}[k]$, and thus the optimal baseband precoder $\mathbf{F}_{\rm BB}[k]$ can be expressed as
\begin{equation}\label{F_BB}
\begin{aligned}
\mathbf{F}_{\rm BB}[k]=&(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}\mathbf{\widetilde{F}}_{\rm BB}[k]
\\=&(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}[\mathbf{\widetilde{V}}[k]]_{:,1:N_s}\mathbf{\Lambda}[k],
\end{aligned}
\end{equation}
where $\mathbf{\Lambda}[k]=(\mu -N_s/[\mathbf{\widetilde{\Sigma}}[k]]_{i,i}^2)^+$ ($1\leq i\leq N_s$, $1\leq k\leq K$) is a water-filling solution matrix, in which $\mu$ satisfies $\sum_{k=1}^K\sum_{i=1}^{N_s}(\mu-N_s/[\mathbf{\widetilde{\Sigma}}[k]]_{i,i}^2)^+=KN_s$.
Then the problem reduces to obtain the optimal solution of $\mathbf{F}_{\rm RF}$ to (\ref{opt_RF}).
\subsection{PCA-Based RF Precoder Design}
Previous work \cite{fre_flat} has shown that the frequency domain MIMO channel matrices $\{\mathbf{H}[k]\}_{k=1}^K$ have the same column space and row space. Meanwhile, the frequency-flat RF precoder $\mathbf{F}_{\rm RF}$ remains unchanged for all subcarriers. So the RF precoder can be regarded as a representation of such a column space. This observation motivates us to design the RF precoder by leveraging the PCA \cite{mach_lern}. Specifically, we first define the optimal digital precoder $\mathbf{F}_{\rm opt}[k]=[\mathbf{V}[k]]_{:,1:N_s}$ for $1\leq k\leq K$. Moreover, we regard the matrix $\mathbf{F}=\begin{bmatrix}\mathbf{F}_{\rm opt}[1]\ \mathbf{F}_{\rm opt}[2]\ \cdots\ \mathbf{F}_{\rm opt}[K]\end{bmatrix}$
consisting of the optimal precoders of all subcarriers as the data set
in the PCA problem. Additionally, to achieve the stable solution with low complexity for PCA,
SVD is applied to the data set matrix $\mathbf{F}$ \cite{mach_lern}. This process is detailed in Proposition 1, where its optimality is also verified as follows.
\newtheorem{prop}{\textbf{Proposition}}
\begin{prop}
    Considering $\mathbf{F}=\begin{bmatrix}\mathbf{F}_{\rm opt}[1]\ \mathbf{F}_{\rm opt}[2]\ \cdots\ \mathbf{F}_{\rm opt}[K]\end{bmatrix}$ and its SVD $\mathbf{F}=\mathbf{U}_F\mathbf{\Sigma}_F\mathbf{V}_F^H$, the solution to (\ref{opt_RF}) can be expressed as $\mathbf{F}_{\rm RF}=[\mathbf{U}_F]_{:,1:N_t^{\rm RF}}\mathbf{R}_t$, where $\mathbf{R}_t\in\mathbb{C}^{N_t^{\rm RF}
	\times N_t^{\rm RF}}$ is an arbitrary full rank matrix.
\end{prop}
\begin{proof}
	Following the similar steps of the equations (12)-(14) in \cite{OMP} and defining $[\mathbf{\Sigma}[k]]_{1:N_s,1:N_s}=\mathbf{\Sigma}_1[k]$, the objective function of the optimization problem in (\ref{opt}) can be approximately written as
\begin{equation}
\begin{aligned}
&\sum\nolimits_{k=1}^{K}\log_2|\mathbf{I}+\tfrac{1}{\sigma_n^2}\mathbf{H}[k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]
\mathbf{F}_{\rm BB}^H[k]\mathbf{F}_{\rm RF}^H\mathbf{H}^H[k]|
\\\approx&\!\sum\nolimits_{k=1}^{K}\!(\log_2\!|\mathbf{I}_{N_s}\!\!+\!\!\tfrac{1}{\sigma_n^2}
\!\mathbf{\Sigma}_1^2[k]|
\!-\!(\!N_s\!\!-\!\!||\mathbf{F}_{\rm opt}^H\![k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]||_F^2)\!).
\end{aligned}
\end{equation}
Therefore, the optimization problem (\ref{opt}) is equivalent to the following optimization problem
\begin{equation} \label{opt_final}
\begin{aligned}
\max\limits_{\mathbf{F}_{\rm RF},\mathbf{F}_{\rm BB}}&\sum\nolimits_{k=1}^{K}||\mathbf{F}_{\rm opt}^H[k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]||_F^2
\\\text{s.t. }&\mathbf{F}_{\rm RF}\in\mathcal{F}_{\rm RF},\sum\nolimits_{k=1}^K||\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]||_F^2=KN_s,
\end{aligned}
\end{equation}
where $\mathcal{F}_{\rm RF}$ is a set of feasible RF precoder satisfying constant-modulus constraint.
The objective function in (\ref{opt_final}) can be written as
\begin{equation
\begin{aligned}
\sum\nolimits_{k=1}^{K}&\!\!\!\!\!\!
||\mathbf{F}_{\rm opt}^H\![k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]||_F^2
\!=\!\!\sum\nolimits_{k=1}^{K}\!\!\!\!\!\!\!\!\text{Tr}(\mathbf{F}_{\rm opt}^H\![k]\mathbf{F}_{\rm RF}\!(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF}\!)\!^{-\!\frac{1}{2}}
\\&\times(\mathbf{\widetilde{F}}_{\rm BB}[k]\mathbf{\widetilde{F}}_{\rm BB}^H[k])
(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm opt}[k]).
\end{aligned}
\end{equation}
According to previous work \cite{uni_cons}, unitary constraints offer a close performance to the total power constraint while providing a relatively simple form of solution. To simplify the problem, we consider condition under unitary power constraints instead. Therefore, water-filling power allocation coefficients can be ignored. In detail, the equivalent baseband precoder $\mathbf{\widetilde{F}}_{\rm BB}[k]=[\mathbf{\widetilde{V}}[k]]_{:,1:N_s}$, which means that $\mathbf{\widetilde{F}}_{\rm BB}[k]$ is a unitary or simi-unitary matrix depending on the relationship between $N_s$ and $N_t^{\rm RF}$. When $N_s=N_t^{\rm RF}$, $\mathbf{\widetilde{F}}_{\rm BB}[k]\mathbf{\widetilde{F}}_{\rm BB}^H[k]$ is $\mathbf{I}_{N_s}$. When $N_s<N_t^{\rm RF}$, denoting the SVD of $\mathbf{\widetilde{F}}_{\rm BB}[k]=\mathbf{U}_{\rm BB}[k]\begin{bmatrix}
\mathbf{I_{N_s}} \ \mathbf{0} \end{bmatrix}^T\mathbf{V}_{\rm BB}^H[k]$, thus $\mathbf{\widetilde{F}}_{\rm BB}[k]\mathbf{\widetilde{F}}_{\rm BB}^H[k]=\mathbf{U}_{\rm BB}[k]\text{blkdiag}(\mathbf{I}_{N_s},\mathbf{0}_{N_t^{\rm RF}-N_s})\mathbf{U}_{\rm BB}^H[k]$. Therefore, the solution to the condition when $N_s=N_t^{\rm RF}$ will also suffice the condition when $N_s<N_t^{\rm RF}$. Therefore, the (\ref{opt}) goes down to $\sum_{k=1}^{K}||\mathbf{F}_{\rm opt}^H[k]\mathbf{F}_{\rm RF}(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}||_F^2$.
Considering SVD of $\mathbf{F}_{\rm RF}=\mathbf{U}_{\rm RF}\mathbf{\Sigma}_{\rm RF}\mathbf{V}_{\rm RF}^H$, previous function can be written as
\begin{equation}\label{s_eq_RF}
\begin{aligned}
&\sum_{k=1}^{K}||\mathbf{F}_{\rm opt}^H[k]\mathbf{F}_{\rm RF}(\mathbf{F}_{\rm RF}^H\mathbf{F}_{\rm RF})^{-\frac{1}{2}}||_F^2=\sum_{k=1}^{K}
||\mathbf{F}_{\rm opt}^H[k]\mathbf{U}_{\rm RF}||_F^2
\\=&\text{Tr}(\sum_{k=1}^{K}\mathbf{U}_{\rm RF}^H\mathbf{F}_{\rm opt}[k]\mathbf{F}_{\rm opt}^H[k]\mathbf{U}_{\rm RF})
\\=&\text{Tr}(\begin{bmatrix}
\mathbf{U}_{\rm RF}^H\mathbf{F}_{\rm opt}[1] & \cdots & \mathbf{U}_{\rm RF}^H\mathbf{F}_{\rm opt}[K]
\end{bmatrix}
\begin{bmatrix}
\mathbf{F}_{\rm opt}^H[1]\mathbf{U}_{\rm RF} \\
\vdots \\
\mathbf{F}_{\rm opt}^H[K]\mathbf{U}_{\rm RF}
\end{bmatrix})
\\=&\text{Tr}(\mathbf{U}_{\rm RF}^H\mathbf{F}\mathbf{F}^H\mathbf{U}_{\rm RF})=\text{Tr}(\mathbf{U}_{\rm RF}^H\mathbf{U}_F\mathbf{\Sigma}_F^2\mathbf{U}_F^H\mathbf{U}_{\rm RF}).
\end{aligned}
\end{equation}
Since both $\mathbf{U}_{\rm RF}$ and $\mathbf{U}_F$ are unitary matrix, (\ref{s_eq_RF}) reaches the maximum only when $\mathbf{U}_{\rm RF}=\mathbf{U}_F$. Moreover, the rank of $\mathbf{F}_{\rm RF}$ is $N_t^{\rm RF}$. So, it is safe to say that $\mathbf{U}_{\rm RF}=[\mathbf{U}_F]_{:,1:N_t^{\rm RF}}\mathbf{U}_R$. Hence the optimal RF precoder can be expressed as
\begin{equation}\label{F_RF}
\mathbf{F}_{\rm RF}=[\mathbf{U}_F]_{:,1:N_t^{\rm RF}}\mathbf{U}_R\mathbf{\Sigma}_{\rm RF}\mathbf{V}_{\rm RF}^H=\mathbf{U}_F\mathbf{R}_t,
\end{equation}
where $\mathbf{R}_t=\mathbf{U}_R\mathbf{\Sigma}_{\rm RF}\mathbf{V}_{\rm RF}^H\in\mathbb{C}^{N_t^{\rm RF}
\times N_t^{\rm RF}}$ is an arbitrary full rank matrix.
\end{proof}

According to Proposition 1, we can obtain the principal
components constituting the optimal RF precoder using PCA.
Moreover, we will design the full-rank matrix $\mathbf{R}_t$ to
meet the requirement of constant-modulus constraint for RF
precoder. Specifically, by taking the constant-modulus constraint of RF precoder into account, we can design the RF precoder by solving
\begin{equation}\label{angle_sel}
\mathbf{F}_{\rm RF}=\arg\min_{|[\mathbf{X}]_{i,j}|=1/\sqrt{N_t}}||\mathbf{X}-
[\mathbf{U}_F]_{:,1:N_t^{\rm RF}}||^2_F.
\end{equation}
With the constant-modulus constrains, the set of possible $\mathbf{F}_{\rm RF}$ is actually a hypersphere in the space of $\mathbb{C}^{N_t\times N_t^{\rm RF}}$, and $[\mathbf{U}_f]_{:,1:N_t^{\rm RF}}$ is a known point in the space of $\mathbb{C}^{N_t\times N_t^{\rm RF}}$. Therefore, the optimization problem in (\ref{angle_sel}) is actually a distance minimization problem. Naturally, the solution is the point on this hypersphere sharing same direction of the know point. In other words, the solution is given by $[\mathbf{F}_{\rm RF}]_{i,j}=1/\sqrt{N_t}e^{j\angle([\mathbf{U}_f]_{i,j})}$, and $\angle(\alpha)$ denotes the phase of a complex number $\alpha$.The specific RF precoder design is summarized in Algorithm \ref{alg:PCA_AS}.
\begin{algorithm}[htb]
	\caption{ PCA-based RF Precoder Design.}
	\label{alg:PCA_AS}
	\begin{algorithmic}[1]
		\renewcommand{\algorithmicrequire}{\textbf{Input:}}
		\renewcommand\algorithmicensure {\textbf{Output:}}
		\Require
		Optimal precoder $\mathbf{F}_{\rm opt}$,
		number of RF chains $N_t^{\rm RF}$,
		number of antennas $N_t$.
		\Ensure
		RF precoder $\mathbf{F}_{\rm RF}$.
		\State $\mathbf{F}=\begin{bmatrix}\mathbf{F}_{\rm opt}[1]\ \mathbf{F}_{\rm opt}[2]\ \cdots\ \mathbf{F}_{\rm opt}[K]\end{bmatrix}$
		\State Apply SVD to $\mathbf{F}$, i.e., $\mathbf{F}=\mathbf{U}_F\mathbf{\Sigma}_F\mathbf{V}_F^H$, where $\mathbf{U}_F$ corresponds to the principal components
		\State $[\mathbf{F}_{\rm RF}]_{i,j}=\tfrac{1}{\sqrt{N_t}}e^{j\angle([\mathbf{U}_F]_{i,j})}$
	\end{algorithmic}
\end{algorithm}

When the quantization of phase shifters is considered, we assume the quantization bits are $Q$. Therefore, the phase shifters can only be chosen from the following quantized phase set $\mathcal{Q}=\{0,\frac{2\pi}{2^Q},\cdots,\frac{2\pi(2^Q-1)}{2^Q}\}$. Specifically, after obtaining the RF precoder $\mathbf{F}_{\rm RF}$, the quantization process can be realized by searching for the minimum Euclidean distance between $\angle([\mathbf{F}_{\rm RF}]_{i,j})$ and quantized phase from $\mathcal{Q}$.
\section{Hybrid Combiner Design at Receiver}
In this section, we assume that $\mathbf{F}_{\rm RF}$ and $\{\mathbf{F}_{\rm BB}[k]\}_{k=1}^K$ are fixed and seek to design the hybrid combiner to minimize the mean-square-error (MSE) between the received signal and the transmitted signal \cite{OMP}. Specifically, the optimal fully-digital minimum mean square error (MMSE) combiner can be expressed as
\begin{equation}
\begin{aligned}\label{W_opt}
\mathbf{W}_{\rm opt}^H[k]\!=\!&\mathbf{W}_{\rm MMSE}^H[k]
\!=\!\tfrac{\sqrt{\rho}}{N_s}\mathbf{F}_{\rm BB}^H[k]\mathbf{F}_{\rm RF}^H\mathbf{H}^H[k]
(\!\tfrac{\rho}{N_s}\mathbf{H}[k]\mathbf{F}_{\rm RF}
\\&\times\mathbf{F}_{\rm BB}[k]\mathbf{F}_{\rm BB}^H[k]\mathbf{F}_{\rm RF}^H\mathbf{H}^H[k]+\sigma_{\rm n}^2\mathbf{I}_{N_r})^{-1},
\end{aligned}
\end{equation}
for $1\leq k\leq K$. Denoting the signal at the receiving antenna as $\mathbf{y}\in\mathbb{C}^{N_r\times 1}$, the combiner design MSE problem is
\begin{equation}\label{MSE}
\begin{aligned}
	\min\limits_{\mathbf{W}_{\rm RF},\mathbf{W}_{\rm BB}}&\sum\nolimits_{k=1}^{K}\mathbb{E}[||\mathbf{x}[k]-\mathbf{W}_{\rm BB}^H[k]\mathbf{W}_{\rm RF}^H\mathbf{y}[k]||_2^2]
	\\\text{s.t. }&\mathbf{W}_{\rm RF}\in\mathcal{W}_{\rm RF},
\end{aligned}
\end{equation}
where $\mathcal{W}_{\rm RF}$ is a set of feasible RF precoder satisfying constant-modulus constraint. Note that if the constant-modulus
constraint in (\ref{MSE}) is removed, the solution to (\ref{MSE}) is the optimal fully-digital
MMSE combiner in (\ref{W_opt}). On the other hand, we observe that the objective
function in (\ref{MSE}) can be further expressed as
\begin{equation}\label{inner_MSE}
\begin{aligned}
	&\sum\nolimits_{k=1}^{K}\mathbb{E}[||\mathbf{x}[k]-\mathbf{W}_{\rm BB}^H[k]\mathbf{W}_{\rm RF}^H\mathbf{y}[k]||_2^2]
	\\=&\!\sum_{k=1}^{K}\!\text{Tr}(\mathbb{E}[\mathbf{x}[k]\mathbf{x}\!^H\![k]])
	\!-\!2\!\sum_{k=1}^{K}\!\mathcal{R}\{\text{Tr}(\mathbb{E}[\mathbf{x}[k]\mathbf{y}\!^H\![k]]\mathbf{W}\!_{\rm RF}\!\mathbf{W}\!_{\rm BB}[k]\!)\!\}
	\\&+\text{Tr}(\mathbf{W}_{\rm BB}^H[k]\mathbf{W}_{\rm RF}^H\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm RF}\mathbf{W}_{\rm BB}[k]).
\end{aligned}
\end{equation}
Since the optimization variables in (\ref{MSE}) are $\mathbf{W}_{\rm RF}$ and $\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$, any term independent
with $\mathbf{W}_{\rm RF}$ and $\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$ will not influence the outcome. Thus we add the independent term $\sum_{k=1}^{K}\text{Tr}(\mathbf{W}_{\rm opt}^H[k]\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\\\times\mathbf{W}_{\rm opt}[k])-\sum_{k=1}^{K}\text{Tr}(\mathbb{E}[\mathbf{x}[k]\mathbf{x}^H[k]])$ to the objective function (\ref{inner_MSE}). So the objective
function in (\ref{MSE}) can be rewritten as
\begin{equation}\label{problem_W}

\sum\nolimits_{k=1}^{K}||\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}(\mathbf{W}_{\rm opt}[k]\!\!-\!\!\mathbf{W}_{\rm RF}\mathbf{W}_{\rm BB}[k])||_F^2
\end{equation}
where $\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]=
(\rho/N_s)\mathbf{H}[k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]\mathbf{F}_{\rm BB}^H[k]
\cdot\mathbf{F}_{\rm RF}^H\mathbf{H}^H[k]+\sigma_{\rm n}^2\mathbf{I}_{N_r}$ and $\mathcal{W}_{\rm RF}$ is the constant-modulus constraint. Similar to the precoder design, we derive the structure of the optimal RF combiners that solves (\ref{problem_W}).
\begin{prop}
	Considering $\mathbf{W}=\begin{bmatrix}
    \mathbb{E}[\mathbf{y}[1]\mathbf{y}[1]^H]^{1/2}\mathbf{W}_{\rm opt}[1] \ \cdots \ \mathbb{E}[\mathbf{y}[K]\mathbf{y}[K]^H]^{1/2}\mathbf{W}_{\rm opt}[K]
	\end{bmatrix}$ and its SVD $\mathbf{W}=\mathbf{U}_W\mathbf{\Sigma}_W\mathbf{V}_W^H$, the solution to (\ref{problem_W}) can be written as $\mathbf{W}_{\rm RF}=[\mathbf{U}_W]_{:,1:N_r^{\rm RF}}\mathbf{R}_r$, where $\mathbf{R}_r\in\mathbb{C}^{N_r^{\rm RF}
	\times N_r^{\rm RF}}$ is an arbitrary full rank matrix.
\end{prop}
\begin{proof}
	Consider least square (LS) estimation for baseband combiner $\mathbf{W}_{\rm BB}[k]=(\mathbf{W}_{\rm RF}^H\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm RF})^{-1}\mathbf{W}_{\rm RF}^H\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm opt}[k]$ ($k=1,\cdots,K$). Substituting LS estimation for baseband combiner in the objective function of (\ref{problem_W}), we have
\begin{equation
\begin{aligned}
&\sum_{k=1}^{K}||\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}(\mathbf{W}_{\rm opt}[k]-\mathbf{W}_{\rm RF}\mathbf{W}_{\rm BB}[k])||_F^2
\\=&\sum_{k=1}^{K}||\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}\mathbf{W}_{\rm opt}[k]-\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}\mathbf{W}_{\rm RF}(\mathbf{W}_{\rm RF}^H
\\&\times\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm RF})^{-1}\mathbf{W}_{\rm RF}^H\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm opt}[k])||_F^2.
\end{aligned}
\end{equation}
Let $\mathbf{A}[k]=\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}\mathbf{W}_{\rm opt}[k]$ and $\mathbf{B}[k]=\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}\mathbf{W}_{\rm RF}$. The above equation can be further simplified as
\begin{equation
\sum_{k=1}^{K}(\text{Tr}(\mathbf{A}\!^H\![k]\mathbf{A}[k]\!)
-\!\text{Tr}(\mathbf{A}\!^H\![k]\mathbf{B}[k](\mathbf{B}\!^H\![k]
\mathbf{B}[k])\!^{-1}\mathbf{B}\!^H\![k]\mathbf{A}[k])\!).
\end{equation}
So the minimization problem can be transformed into following maximization problem
\begin{equation}\label{max_W}
\max_{\mathbf{W}_{\rm RF},\mathbf{W}_{\rm BB}[k]}\sum_{k=1}^{K}\text{Tr}(\mathbf{A}^H[k]\mathbf{B}[k](\mathbf{B}^H[k]
\mathbf{B}[k])^{-1}\mathbf{B}^H[k]\mathbf{A}[k]).
\end{equation}
Assuming the SVD of $\mathbf{B}[k]=\mathbf{U}_B[k]\mathbf{\Sigma}_B[k]\mathbf{V}_B^H[k]$, the objective function of the maximization problem (\ref{max_W}) can be written as $\sum_{k=1}^{K}||\mathbf{U}_B^H[k]\mathbf{A}[k]||_F^2$.
Since $\mathbf{B}[k]=\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{\frac{1}{2}}\mathbf{W}_{\rm RF}$, we can safe to say that there is a matrix $\mathbf{R}_B[k]\in\mathbb{C}^{N_r^{\rm RF}
\times N_r^{\rm RF}}$ satisfying $\mathbf{U}_B[k]=\mathbf{R}_B[k]\mathbf{U}_W$. So the problem can be transformed into $\sum_{k=1}^{K}||\mathbf{U}_W^H\mathbf{R}_B^H[k]\mathbf{A}[k]||_F^2$.
Note that function above is similar to the objective function of maximization problem (\ref{opt_final}), thus $\mathbf{W}_{\rm RF}=[\mathbf{U}_V]_{:,1:N_r^{\rm RF}}\mathbf{R}_v$, where
\begin{equation
\begin{aligned}
\mathbf{V}=&[\mathbf{R}_B^H[1]\mathbf{A}[1]\ \cdots \ \mathbf{R}_B^H[K]\mathbf{A}[K]]
\\=&\text{blkdiag}(\mathbf{R}_B^H[1],\cdots,\mathbf{R}_B^H[K])\mathbf{W}.
\end{aligned}
\end{equation}
Therefore, matrix $\mathbf{U}_R$ satisfies $[\mathbf{U}_V]_{:,1:N_r^{\rm RF}}=[\mathbf{U}_W]_{:,1:N_r^{\rm RF}}\mathbf{U}_R$. So the solution to the problem (\ref{max_W}) is
\begin{equation}
\begin{aligned}
&\mathbf{W}_{\rm RF}=[\mathbf{U}_V]_{:,1:N_r^{\rm RF}}\mathbf{R}_v
\\=&[\mathbf{U}_W]_{:,1:N_r^{\rm RF}}\mathbf{U}_R\mathbf{R}_v=[\mathbf{U}_W]_{:,1:N_r^{\rm RF}}\mathbf{R}_r,
\end{aligned}
\end{equation}
where $\mathbf{R}_r\in\mathbb{C}^{N_r^{\rm RF}
\times N_r^{\rm RF}}$ is an arbitrary full rank matrix.
\end{proof}

The design of RF combiner can be extended from that of the RF precoder, where the weight $\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]$ should be considered according to MMSE criterion. The RF combiner design is provided in Algorithm \ref{alg:w_PCA_AS}.
\begin{algorithm}[htb]
	\caption{ Weighted PCA-based RF Combiner Design.}
	\label{alg:w_PCA_AS}
	\begin{algorithmic}[1]
		\renewcommand{\algorithmicrequire}{\textbf{Input:}}
		\renewcommand\algorithmicensure {\textbf{Output:}}
		\Require
		Optimal combiners $\{\mathbf{W}_{\rm opt}[k]\}_{k=1}^K$,
        covariance matrices of the received signals $\{\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{1/2}\}_{k=1}^K$,
		the number of RF chains $N_r^{\rm RF}$,
		and the number of antennas $N_r$.
		\Ensure
		RF combiner $\mathbf{W}_{\rm RF}$.

        \State $\mathbf{W}_w[k]=\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]^{1/2}\mathbf{W}_{\rm opt}[k]$, for $k=1,\cdots,K$
        \State $\mathbf{W}=\begin{bmatrix}\mathbf{W}_w[1]\ \mathbf{W}_w[2]\ \cdots\ \mathbf{W}_w[K]\end{bmatrix}$
		\State Apply SVD to $\mathbf{W}$, i.e., $\mathbf{W}=\mathbf{U}_W\mathbf{\Sigma}_W\mathbf{V}_W^H$, where $\mathbf{U}_W$ corresponds to the principal components
		\State $[\mathbf{W}_{\rm RF}]_{i,j}=\frac{1}{\sqrt{N_r}}e^{j\angle([\mathbf{U}_W]_{i,j})}$
	\end{algorithmic}
\end{algorithm}
When consider quantization of phase shifters, the entries of $\angle([\mathbf{W}_{\rm RF}]_{i,j})$ are substituted by the phase in $Q$ bits quantization phase set $\mathcal{Q}$ with minimum Euclidean distance.

Furthermore, the design of baseband combiners $\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$ are different from the design of baseband precoders $\{\mathbf{F}_{\rm BB}[k]\}_{k=1}^K$, since the power constraint is removed for the receive hybrid combiner. Specifically, $\{\mathbf{F}_{\rm BB}[k]\}_{k=1}^K$ is designed according to water-filling algorithm given $\mathbf{F}_{\rm RF}$, while $\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$ is designed by using weighted least squares (LS) according to fully-digital MMSE combiners $\{\mathbf{W}_{\rm opt}[k]\}_{k=1}^K$ and frequency-flat RF combiner $\mathbf{W}_{\rm RF}$. The detailed design of $\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$ can be summarized in Algorithm \ref{alg:comb}.
\begin{algorithm}[htb]
	\caption{ Baseband Combiner Design.}
	\label{alg:comb}
	\begin{algorithmic}[1]
		\renewcommand{\algorithmicrequire}{\textbf{Input:}}
		\renewcommand\algorithmicensure {\textbf{Output:}}
		\Require
		Optimal combiners $\{\mathbf{W}_{\rm opt}[k]\}_{k=1}^K$,
		RF combiner $\mathbf{W}_{\rm RF}$,
		RF precoder $\mathbf{F}_{\rm RF}$,
        baseband precoders $\{\mathbf{F}_{\rm BB}[k]\}_{k=1}^K$,
		channel matrices $\{\mathbf{H}[k]\}_{k=1}^K$,
		and expectation of the received signal $\{\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\}_{k=1}^K$.
		\Ensure
		Baseband combiners $\{\mathbf{W}_{\rm BB}[k]\}_{k=1}^K$.
		\For{$k=1:K$}
		\State $\mathbf{A}=(\mathbf{W}_{\rm RF}^H\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm RF})^{-1}$
        \State $\mathbf{W}_{\rm BB}[k]=\mathbf{A}\mathbf{W}_{\rm RF}^H\mathbb{E}[\mathbf{y}[k]\mathbf{y}^H[k]]\mathbf{W}_{\rm opt}[k]$
		\State $\mathbf{\Lambda}_{\rm eq}=\text{diag}{\{\mathbf{W}_{\rm BB}^H[k] \mathbf{W}_{\rm RF}^H\mathbf{H}[k]\mathbf{F}_{\rm RF}\mathbf{F}_{\rm BB}[k]\}}^{-1}$
		\State $\mathbf{W}_{\rm BB}[k]=\mathbf{W}_{\rm BB}[k]\mathbf{\Lambda}_{\rm eq}$
		\EndFor
	\end{algorithmic}
\end{algorithm}

\section{Simulations}
In this section, we will investigate the SE and BER performance for the hybrid precoder/combiner design for the backhaul/fronthaul channel. For the backhaul/fronthaul channel model, we adopt Dirac delta function as the pulse shaping filter and a cyclic prefix with the length of $D=64$. The number of subcarriers is $K=512$. We consider that the path delay is uniformly distributed in $[0,DT_s]$ ($T_s=1/B$ is the symbol period). The number of the clusters is $N_{\rm cl}=8$, and azimuth/elevation AoAs and AoDs follow the uniform distribution $\mathcal{U}[-\pi/2, \pi/2]$ with angle spread of $7.5^{\circ}$. Within each cluster, there are $N_{\rm ray}=10$ rays. As for the antennas, we consider both the transmitter and receiver adopt $8\times8$ UPA, and the distance between each adjacent antennas is half wavelength.
Moreover, we consider the number of RF chains at transmitter and receiver are $N_t^{\rm RF}=N_r^{\rm RF}=4$ and the data stream is $N_s=3$ unless otherwise stated.

Throughout this part, following baselines will be considered
for performance benchmarks: \textbf{Optimal fully-digital} scheme considers the fully-digital MIMO system, where the SVD-based precoder/combiner is adopted as the performance upper bound. \textbf{Simultaneous OMP (SOMP)} scheme is an extension version of the narrow-band OMP-based spatially sparse precoding in \cite{OMP}. In broadband, SOMP-based hybrid precoding scheme can simultaneously design the RF precoder/combiner for all subcarriers. \textbf{Discrete Fourier transform (DFT) codebook} scheme designs the RF precoder/combiner from the DFT codebook instead of steering vectors codebook in SOMP scheme \cite{DFT_cb}.

\begin{figure}[htb]
    \centering
    \includegraphics[width=0.8\columnwidth, keepaspectratio]{sesysfull.eps}
	\caption{SE performance comparison of different hybrid precoding schemes, where both transmitter and receiver employ $8\times8$ UPA, $N_t^{\rm RF}=N_r^{\rm RF}=4$, and $K=512$.}\label{fig_SE}
\end{figure}
In Fig. \ref{fig_SE}, we evaluate SE performance of the proposed PCA-based hybrid precoding scheme, SOMP-based hybrid precoding scheme, and DFT codebook-based hybrid precoding scheme, where both hybrid precoder and combiner are jointly investigated, and $Q=\infty$ and $Q=3$ are considered, respectively. In Fig. \ref{fig_SE}, the proposed PCA-based hybrid precoding scheme outperforms the SOMP-based hybrid precoding scheme and DFT codebook-based hybrid precoding scheme. The DFT codebook-based hybrid precoding scheme works poorly due to the quantization loss of the DFT codebook with limited size. Finally, it can also be observed from Fig. \ref{fig_SE} that the influence of quantization of phase shifters can be negligible for our scheme.

\begin{figure}[htb]
    \centering
    \includegraphics[width=0.8\columnwidth, keepaspectratio]{berfca.eps}\\
	\caption{BER performance comparison of different hybrid precoding schemes, where both transmitter and receiver employ $8\times8$ UPA, $N_t^{\rm RF}=N_r^{\rm RF}=4$, and $K=128$.}\label{fig_BER}
\end{figure}
In Fig. \ref{fig_BER}, we evaluate the BER performance of the proposed PCA-based hybrid precoding scheme, SOMP-based hybrid precoding scheme, and DFT codebook-based hybrid precoding scheme, where both hybrid precoder and combiner are jointly investigated, 16 QAM is adopted for transmission, and $Q=\infty$ and $Q=3$ are considered, respectively. For simplicity, only $K=128$ subcarriers are considered in the system. As shown in Fig. \ref{fig_BER}, the proposed PCA-based hybrid precoding scheme outperforms the conventional SOMP-based and DFT codebook-based hybrid precoding schemes in BER performance. Meanwhile, the SOMP-based hybrid precoding scheme has the worst BER performance, especially at high SNR. When BER$=10^{-2}$ is considered, we can observe that the proposed scheme outperforms the DFT-codebook-based hybrid precoding scheme and the SOMP-based hybrid precoding scheme by approximately 2 dB and 11 dB, respectively.

\section{Conclusions}
This paper has proposed a PCA-based hybrid precoder
and combiner for wideband mmWave FD-MIMO backhaul/fronthaul channels. To design the precoder, we use the PCA algorithm to extract the principal components from the optimal fully-digital precoders of all subcarriers and choose its phase angles as the angles of RF precoder. Moreover, the RF combiner at the receiver can be built by implementing the weighted PCA, and baseband combiner can be designed by using the weighted LS. Simulations further verify both the better SE and BER performance of the proposed scheme than conventional schemes. The scheme proposed in this paper can also be used in cellular communications. However, smaller receive antenna array and multiple users are often considered in cellular communications, which will be investigated in future work.

\section*{Acknowledgment}
This work was supported by the National Natural Science Foundation of China (Grant Nos. 61471037, 61701027, and 61201181), the Beijing Natural Science Foundation (Grant No. 4182055), Huawei Innovation Research Program (HIRP), and Youth Project of China Academy of Information and Communications Technology.

redpajama_set_name: RedPajamaArXiv


Firstly, the Japanese anime - it's a genre film, which usually has a lot of sequels and a long history. This is not Shakespeare's Hamlet or Avatar Kamerona, which takes years to literacy adaptation or elaboration of all details. It's an anime for the average and unassuming viewer who wants to take your free time.
Second, the anime series Gods Eater differs interesting plot and high-quality graphics. The focus of the audience was the trio of heroes who possess some divine weapon. And so the three heroes of the Cross begin a campaign against the terrible monsters that have long terrorized the civilian population. Chief among that trio becomes Soma, which is taking the lead in this work.
Interesting storyline and rich soil for a fascinating fantasy guarantee the possibility to continue, which may come out in 2016.
Anime God Eater season 2 may be one of the best. Director Takayuki Hirao currently has not made an official statement about the release date continue. Exact release date is unknown, but we can confidently say that God Eater season 2 will be. We can only wait for the end of 2016. If you like the genre Adventure, Anime look like at the end of the news.
When it would be released?
When will season 2 of God eater get dubbed in English?
Subscribe to receive last news and updates status ゴッドイータ. You will receive an automatic email when the anime released.


text:
Onion hits two-year high of Rs 4,900 per quintal in India's largest wholesale market in Nashik
To keep prices of onions in check, the Centre has asked state-owned MMTC to float a global tender for import of 10,000 tonnes of onions.
Updated:August 20, 2015, 3:07 PM IST
New Delhi: Wholesale onion prices on Thursday hit two-year high of Rs 4,900 per quintal, after it shot up by Rs 400 at the country's largest bulb wholesale market in Lasalgaon, Nashik.
As per NHRDF data, onions which were selling at a wholesale price of Rs 4,500 per quintal at Lasalgaon, on Thursday
rose to Rs 4,900 per quintal. "Prices have today touched two-year high at Lasalgaon mainly due to decline in supplies as harvesting of onion has been delayed and now it seems that there will also be fall in production of kharif onion," National Horticultural Research and Development Foundation (NHRDF) Director RP Gupta said.
Gupta said that there are chances of substantial decline in kharif onion production from Maharashtra, Karnataka and Andhra Pradesh due to deficient rainfall, while there is also a threat of drought in these states. "Besides, the harvesting of onion has got delayed in Gujarat, Rajasthan and Madhya Pradesh," he added.
Further, the stored rabi onion in the country has halved to 14 lakh tonnes from 28 lakh tonnes in July. Total onion production is estimated to be at 189 lakh tonnes in 2014-15 crop year (July-June), slightly lower than 194 lakh tonnes, a year ago.
In order to keep prices of onions in check and ensure smooth supplies, the Centre has already asked state-owned MMTC to float a global tender for import of 10,000 tonnes of onions.
Meanwhile, Punjab traders have also started importing onions in small quantities from Afghanistan through the Attari-Wagah land route. Retail prices of onion have already touched Rs 80 per kg in the national capital. In its bid to offer relief to consumers from high prices, the Delhi government has facilitated sale of onions at a subsidised rate of Rs 30 per kg.
Kharif
'Virat Kohli' is a TikTok Star and No We aren't Talking About Team India Captain

redpajama_set_name: RedPajamaCommonCrawl


text:
Solving Email Overload With A Company-Wide Ban
December 01, 2011 at 16:34 PM EST
The CEO of a large European-based tech firm hates email and wants his 74,000 employees in 42 countries to stop using it. Thierry Breton , CEO of Atos , wants his "zero email" policy to be in place within a year-and-a-half. He told the Daily Mail only 10% of emails turn out to be important and that "email is no longer the appropriate tool. It is time to think differently."
The CEO of a large European-based tech firm hates email and wants his 74,000 employees in 42 countries to stop using it. Thierry Breton, CEO of Atos, wants his "zero email" policy to be in place within a year-and-a-half. He told the Daily Mail only 10% of emails turn out to be important and that "email is no longer the appropriate tool. It is time to think differently."
TechCrunch writers have a long history of trying to solve email overload. MG Siegler quit email for a month earlier this year and wrote about it when his experiment ended. Michael Arrington has discussed his email overload problem and how it's an opportunity for an entreprenuer. We covered Gmail Priority Inbox which helps you focus on the important emails. I wrote about the 3 sentence email concept. We've also written about Shortmail, which tries to keep email, well, short. And there have been many other posts too.
But, none of these attempts are as drastic as Breton's company-wide plan. He says one of the big problems is people switching to 'useless' emails when they were working on more important tasks. Also, he complains "It is not right that some of our fellow employees spend hours in the evening dealing with their emails." That's clearly the standard practice in Silicon Valley and the start-up world.
Breton's solution is employees should spend more time talking directly to each other in person or on the phone. And he wants them to use real time messaging tools, saying the chat tools on Facebook would be better than email.
This is not the first time Breton has preached against email. Back in February, he told an innovation conference his firm would be a "zero email company" within three years. A writer at Computerworld suggests this might just be an elaborate PR effort for Atos's IT service business, and he might be right.
I also wonder what happens to the 10 percent of emails that even Breton admits are important. What business opportunities and improvements might be missed with a zero email policy? Yes, many of us really hate email overload. If email served no useful purpose, we wouldn't use it. But that's not the case, and a company-wide ban sounds like the wrong solution. It will be interesting to see if Breton's ban really gets put into place and how the company then performs.
[Image: olly/Shutterstock]


text:
Three Ways the WWE Has Dropped the Ball with Evolution
Sade Hale
Sade H. is a writer and media practitioner from D.C.
DDT Divas Evolution Fantasy Match Card
On July 23, during an episode of Monday Night Raw, Stephanie McMahon made a historic announcement; the WWE is hosting its first ever all women's pay-per-view, Evolution. As the news broke and the anticipation built, many fans began looking forward to Sunday, October 28.
Several questions began to hit the internet. What matches would be booked on the card? Who would make an in-ring return? Will the WWE introduce Women's Tag Team Championships? Major rumors also made their way to the internet, including a leaked pay-per-view card.
As of today, only four matches from the leaked pay-per-view card are true. These matches are:
Ronda Rousey (c) vs Nikki Bella for the WWE Raw Women's Championship
Becky Lynch (c) vs Charlotte Flair for the WWE SmackDown Women's Championship
The Mae Young Classic Finals
An NXT Women's Championship match
There have been a few match changes that have been confirmed that were included on the leaked card:
Mickie James vs Lita and Alexa Bliss vs Trish Stratus is now a tag team match. Mickie James and Alexa Bliss vs Lita and Trish Stratus
A 20 Women's Battle Royal winner facing Kairi Sane for the NXT Women's Championship has now been separated into two matches
A Women's Battle Royal for a #1 contender spot
Kairi Sane (c) vs Shayna Baszler
The leaked card also included a Women's Tag Team Championship match, an NXT UK Women's Championship match, a six-woman tag team match, and single matches for Asuka, Ember Moon, and Naomi.
Welp, we are six days away and Evolution isn't looking as stacked or exciting, especially for such a historic event. Even the biggest and most supportive women's wrestling fans are on pins & needles.
Yep, the WWE seems to have dropped the ball with Evolution and here's how:
Last Minute Marketing and Promotion
It's been almost three months since the Evolution announcement. Instead of starting their promotional campaigns for Evolution soon after the announcement, the WWE waited, waited, and waited. Super Show-Down promotion was in full swing, but very little mention of Evolution. Then, after Super Show-Down, fans were sure Evolution marketing would pick up. Nope! Crown Jewel came along and grabbed all the spotlight, a pay-per-view that is only a few days after Evolution.
To make matters worse, Crown Jewel is being held in Riyadh, Saudi Arabia, a country where women are not allowed to participate because of Saudi Arabian law. Because of this, some fans believe Evolution is just an elaborate PR move to avoid negative media attention since the WWE is once again returning to Saudi Arabia.
But in the wake of the disappearance and murder of Washington Post journalist Jamal Khashoggi, the WWE's Crown Jewel is now gaining a lot of negative press. One would think the WWE would ease up on promoting Crown Jewel and focus more on Evolution. Nope! Even after bipartisan political criticism, WWE continues to focus on Crown Jewel. RIP Evolution marketing campaigns.
Uninspiring Booking and Pay-Per-View Card
For a first ever WWE event, the WWE should go all out. Again, this is historic! The pay-per-view card should have been filled with championship matches, dream matches, in-ring returns, and high-quality match potential. While the match quality potential seems good, the card is lacking in dream match ups and the heavy rumored WWE Women's Tag Team Championships.
For months now, rumors have circulated. Many fans wonder what's up with all the new tag team creations if the WWE doesn't plan on creating a women's tag division.
As of now, there are about eight tag teams:
Absolution (SmackDown)
The IIconics (SmackDown)
Asuka and Naomi (SmackDown)
The Riott Squad (Raw)*
The Boss 'n' Hug Connection (Raw)*
Nia Jax and Ember Moon (Raw)
Alexa Bliss and Mickie James (Raw)*
The Bella Twins (Raw)*
The Riott Squad, The Boss 'n' Hug Connection, Bliss, James, and Nikki already have matches at Evolution.
Editorial, Live Events
F1ght Club Pro Wrestling Crowns Two Inaugural Champions
It would have been sweet if there was a women's tag team tournament hosted on episodes of Raw and SmackDown that led up to Evolution. The final team from Raw and the final team from SmackDown would meet at Evolution to determine the inaugural Women's tag team champions. As of today, there has been no official mention of tag team titles, but Sasha Banks did mention the titles in a recent Instagram video. So there is a huge chance that they may be introduced very soon.
The pay-per-view card also seems a little limited. Right now, there have been seven matches officially announced and one rumored match (the NXT UK Women's Championship match). That's a total of eight matches. Most WWE pay-per-views have between 10 to 13 matches, with one match on the pay-per-view's kick off show. Seven matches for a three-hour show just doesn't feel right.
Even so, there seems to be room for at least two or three more matches. Plus, there are several talented superstars who just have just been thrown into the Battle Royal, and besides lazy and careless booking, there isn't any reason for Asuka, Ember Moon, Naomi, Nia Jax, and Carmella all being placed in the Battle Royal.
These women are all talented former champs. Asuka and Ember Moon are former NXT champions. Carmella and Naomi are former SmackDown champions, and Nia Jax is a former Raw champion. That's not very creative or astonishing for such a history-making pay-per-view.
It's not that the Battle Royal is pointless. It's not. It's actually a great way to make sure every superstar has a chance to take part in history. But so many former champions shouldn't be thrown into the Battle Royal.
Very Little Storyline Development
In a "which came first" situation, did lazy booking lead to little storyline development or did little storyline development lead to lazy booking? Honestly, it doesn't matter. What matters is the lack of storytelling. The WWE needs to give fans a reason to care about Evolution. Why should fans care?
And while the WWE writers have done a decent job writing the Becky Lynch vs Charlotte Flair and the Kairi Sane vs Shayna Baszler feuds, they haven't done so well with the Ronda Rousey vs Nikki Bella feud. Unlike the other two matches, Ronda vs Nikki lack backstory, emotion, and depth. The Bellas just randomly turned heel and attacked Ronda. Of course, the Raw Women's Championship is a motive for the attack, but what else. Sadly, there isn't much time to build on the feud before Evolution. But shout out to Nikki and Ronda for taking to social media to build on the feud.
With the go home episodes of Raw, SmackDown, NXT, NXT UK, and the Mae Young Classic, there isn't much time left to promote Evolution, fix the uncreative book, and create more in-depth storylines. Evolution still has the potential to entertain, and we may be in for a treat. But the only way we will know is if we watch Evolution next Sunday.
Alexa Bliss Asuka Battle Royal Bayley Becky Lynch Carmella Charlotte Flair Evolution Kairi Sane Lita Mae Young Classic Mickie James Naomi Natalya Nia Jax Nikki Bella NXT UK Women's Championship NXT Women's Championship Raw Women's Championship Ronda Rousey Sasha Banks Shayna Baszler SmackDown Women's Championship The Riott Squad Trish Stratus WWE
Sade Hale October 22, 2018
SmackDown 1000 Photos
Pay-Per-View, Pay-Per-View Review
WWE TLC 2020 Report Card
The UE Came to Fight
WWE Survivor Series 2020 Report Card
Did Dixie Carter Buy NXT Without Us Knowing?
WWE Hell in a Cell 2020 Report Card
The Wheel is Back!!!


Almost every cruising boat carries at least one tender, usually an inflatable or RIB. Whether it lives on chocks on the boat deck, hangs on davits or rests, tipped on its side, on the swim platform, a tender is a both useful and expensive accessory. A little TLC every now and then will make its life longer and happier. And it will make you feel good knowing that you showed affection for the little lady you keep on the side.
Maintaining an inflatable or RIB is about as easy a chore as you'll find on board. Basically, you clean it with mild soap and fresh water after each use, rinse it thoroughly and dry it before reinstalling the floorboards, seats and other accessories. Treat the rigid parts of a RIB as you would any fiberglass boat: Wash often and wax once or twice a season to maintain the gelcoat. Novurania recommends waxing its inflatable tubes as well, once a month to protect against UV-induced oxidation, after using a hand cleaner with lanolin (the stuff mechanics swear by) to remove oil and grease stains.
Even undamaged inflatables lose air, and fairly quickly at that. Most manufacturers consider a 10% loss in pressure over 24 hours to be normal, so if you have to top-up your tubes every day, don't tear your hair out looking for a leak. That's just the way it is. Keep the valves clear of sand, seaweed, and other junk, and you'll minimize your pumping chores. If you need to patch a puncture, use the repair kit supplied by the manufacturer, and follow the directions exactly. Carefully clean the surface with solvent (included in the kit), especially important if you've used silicone, petroleum, or wax on the tubes. Work in a well-ventilated area, and don't breathe any more of the fumes than absolutely necessary.
Finally, if your tender is showing signs of age, you can give it a facelift and extend its lifespan by recoating it. Try SRC Tuff Coat, ( www.tuff-coat.com). It's basically paint-on synthetic rubber, but applied in two layers: The basecoat restores the surface of the tubes, while the topcoat provides the finish. Tuff Coat comes in five colors – gray, white, red, black, and orange. Kits are inexpensive, and if you can paint, you can apply it yourself.


text:
Cute Is What We Aim For plays Rickshaw this weekend by popular demand
By Estefany Gonzalez|October 7, 2016|3 Comments
During emo's golden area, Cute Is What We Aim For released The Same Old Blood Rush With A New Touch, an album that became a a must-have for many music lovers. As the band embarks on a tour for the record's 10-year anniversary, fans submitted enough request to Fanbassador, a site that allows fans to bring artists to specific cities, to add a tour date at Rickshaw Stop in San Francisco.
The band's lineup has undergone a number of changes throughout the years, with frontman Shaant Hacikyan as the only constant member. Now, Tom Falcone and Jeffrey Czum from the respective album are back in the official lineup.
The trio started this reunion with the intent of only playing shows in Australia, but quickly realized they had to play in the states as well. "It was something we had to do," Hacikyan says. "We didn't even think that we were going to be doing the US tour."
The frontman credits the idea to his fans and Fanbassador co-founder Chris Ring. "Fans that were supportive are obviously the ones making this a reality, but it was also our friend Chris," Hacikyan says. "We grew up together and we told him we were going to Australia. We had a meeting with him and asked him what we should do after and he said, 'Well, you should tour the US.'" From there the band announced a full list of tour dates, along with six Fanbassador shows.
While Hacikyan and company played a number of concerts in the Bay with Paramore and Jack's Mannequin, and headlined a few shows too, he's humbled by how many fans he still has in the area. "The response was pretty overwhelming and it just made it undeniable that we had to go play there," he says.
So far, what the frontman has enjoyed the most about the tour is the sense of growing up with his fans. "We were just kids when this came out," he says. "Here we are 10 years later and people are telling us about their kids or how they met their wives or husband at a Cute show."
He said he noticed this type of connection to music growing up, but didn't understand it until he was older. He remembers being over at a friend's house whose dad would constantly play Bon Jovi: "It used to drive me crazy and now here I am, playing Taking Back Sunday every three days just because that's when I was the most impressionable and discovered what I loved."
For Hacikyan there's also a new element to playing these songs live. "There's never a syllable that isn't screamed back. It just makes every single night a total trip," he says.
While anthems such as "Practice Makes Perfect" and "Curse Of Curves" are popular at Emo Night and resonate with fans, the slower songs such as "Lyrical Lies" hold a special place in Hacikyan's heart. The song references his grandfather, who passed away. "He supported me and this crazy dream I had," Hacikyan says. "When we play, I get to talk about him for a moment. I don't know if I believe in the whole someone watching you from the other side but it makes me happy to sing it."
Hacikyan is glad to still be on the road after 10 years. "We were so lucky and it blows our minds to think we're still so lucky," he says.
While the band is currently unsigned, Hacikyan said there will be another Cute album in the near feature. "I want to try and give us a whole go again," he says. "I think it has to happen. Even if it doesn't do well, it'll be nice to know that we just wrote another chapter, one that we could maybe rest our heads on."
Cute Is What We Aim For, Call Sign , Get Married
8pm, $15
P.S. Want more show recommendations, ticket giveaways, and music news? Sign up for our biweekly newsletter!
Tags: Cute Is What We Aim For
Elizabeth Reyes October 7, 2016 at 2:36 pm
FYI – the song title is "Lyrical Lies" not "Lyrical Lying."
Jody Amable October 7, 2016 at 2:53 pm
This has been corrected. We apologize for the error!
Mae October 7, 2016 at 2:32 pm
Sooooo ready for this! Happy early birthday to me!
Photos: Grouplove make a Big Mess at the Fox
Playlist: Get ready for the 2016 Treasure Island Music Festival with over three hours of TIMF jams


This is a rehab center that is focused on helping alcoholics overcome and learn to control the desire to drink. The main target of alcohol rehab centers is to assist their patients in going through the hard period of withdrawal from alcohol along with providing them with coping tool to help them resist drinking in the future. The services of this type of center will usually go beyond support groups and self-help programs. Alcohol rehab centers will offer medical support to ease the physical effects of detoxification and psychological therapy. If you are an inpatient in the program, you would move into the center and receive attention 24/7 as you work to gain control of your alcohol addiction.
There are also outpatient alcohol rehab centers where the patient would choose to remain the home with family members. The outpatient center will establish a regular schedule of counseling, support group activity, and physical examinations to help in the patient's recovery process. The outpatient approach may be more productive but it all depends on how severe the alcohol addiction is. For severe alcohol addiction, it is best if they choose inpatient treatment.
A key fact that alcohol rehab centers take into account is that alcoholism is not a disease that anyone can cure. Once you are an alcoholic you will always be an alcoholic for the remainder of your life. This is the reason that alcohol rehab centers focus on helping the patients to develop coping skills to help them resist the temptation to consume alcohol. During the beginning of the recovery period, the rehab center will provide monitoring to make it a little easier to deal with the withdrawal symptoms that start soon after your body starts to learn to adjust without drinking. Some of these withdrawal symptoms can be very serious and require medical treatment so this is why the patient is carefully monitored when starting alcohol rehab. Depending on the individual, these symptoms can last from several days to months. The more serious symptoms happen to those that are considered hard drinkers and drink more than eight beers a day.
Alcohol rehab centers will also address both the mental and physical impact of alcoholism along with providing them with support, the sill set, and inspiration to overcome their addiction to alcohol and to keep it in check after the treatment is complete. Many who complete successfully the treatment at alcohol rehab centers will continue to participate in support groups in the community. By doing so it will help them to maintain a network of individuals that understand the temptation to drink alcohol and offer support to them to help them resist the urge to drink. Those that are recovering alcoholics will usually join a support group and attend weekly meetings.


text:
BMW Climate Strategy May Influence Manager Compensation
Vanessa Dezem
Jul 26 2020, 3:30 PM Jul 27 2020, 5:09 PM July 26 2020, 3:30 PM July 27 2020, 5:09 PM
(Bloomberg) -- /
German automaker BMW AG is set to announce strict climate targets in the coming days, including requirements that will directly influence managers' compensation, newspaper Frankfurter Allgemeine Sonntagszeitung reported on Sunday, citing internal documents.
The company will commit to save tens of millions of tons of CO2 annually until 2030, according to the newspaper. For that, it will control the entire production cycle -- from raw materials and the use of the car, through to the recycling of batteries. How managers fulfill the requirements will directly influence the variable component of his or her salary.
Automakers' fleet emissions worsened in 2019 versus 2018, according to European Union data, and companies are struggling to comply with EU emission rules.
BMW announced on Friday it plans to make a version of its X5 SUV that runs on hydrogen fuel-cells, part of the carmaker's plan of producing as many drive variants as possible until one technology proves dominant.
MORE: SUVs Help Boost New Car Emissions in Europe Third Year Running
Stay Updated With Business News On BloombergQuint


The Eviatickets.gr began operations in 2007. In a market that was already structured with strong players, eviatickets.gr managed to establish itself and gain a large market share. For 2009 and 2010 Eviatickets.gr was chosen by the Greek public as the most popular online travel agency in Greece, according to the largest Greek Research magazine Conde Nast Traveller.
Our ambition is to expand abroad directly and offer competitive and innovative services to the public. We combine technological knowledge with experienced staff to achieve a customer oriented approach. Almost every month we introduce new services and continue to invest for the future. We're trying to achieve even more and continue to believe that Greek companies can be competitive internationally. We are here to prove it.


The Congress screening committee headed by Ajay Maken shortlisted party candidates for the Rajasthan assembly elections at a meeting in New Delhi on Monday.
Sources said the five-member committee, which had chief minister Ashok Gehlot as a member, shortlisted single-name panels for nearly a quarter of the 200 seats in the state. For another quarter of the seats, the committee prepared two-name panels on day one. Candidates for the remaining seats would be shortlisted on Tuesday.
The announcement of the selected candidates, however, is unlikely before October 23 when party vice-president Rahul Gandhi is scheduled to address two public rallies in Alwar and Churu districts. Names shortlisted by the screening committee would have to be approved by the chief election committee headed by Sonia Gandhi.
The screening committee met in Delhi last week also to shortlist for the candidate selection exercise. Senior party leaders, including union ministers and parliamentarians from the state, were called for their suggestions on the selections in the earlier meetings.
This time, however, the committee is zeroing on the potential candidates in a closed-door meeting with its five members only. The committee is going ahead on the basis of inputs gathered so far through different sources, including independent surveys by the party high command as well as the state leadership. Besides Maken and Gehlot, the screening committee includes Odisha MP R C Khuntia, AICC general secretary in-charge of the state Gurudas Kamat and Congress state president Chandrabhan.


text:
SET statement_timeout = 0;
SET lock_timeout = 0;
SET client_encoding = 'UTF8';
SET standard_conforming_strings = on;
SET check_function_bodies = false;
SET client_min_messages = warning;
SET row_security = off;

--
-- Data for Name: test_vocab; Type: TABLE DATA; Schema: public; Owner: test_admin
--

COPY test_vocab (id, word) FROM stdin;
1	22222
2	a
3	employees
4	social
5	security
6	number
7	omb
8	no
9	15450008
\.

--
-- Name: test_vocab_id_seq; Type: SEQUENCE SET; Schema: public; Owner: test_admin
--

SELECT pg_catalog.setval('test_vocab_id_seq', 9, true);

--
-- PostgreSQL database dump complete
--

redpajama_set_name: RedPajamaGithub


MASETTI, Isaias Quaresma; GOLDIN, F; DIAS, Carlos Alberto Nunes; et al. PROSET: A computer program for moored floating production systems analysis. Anais.. Southampton: Computational Mechanics, 1992.
Masetti, I. Q., Goldin, F., Dias, C. A. N., ,, Petreche, J. R. D., Berardi, A. L., & Curdoso, A. A. (1992). PROSET: A computer program for moored floating production systems analysis. In Design of marine and offshore structures. Southampton: Computational Mechanics.


text:
Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine
David H.W. Wohns, J. Herbert Patterson, Susan Clarke, Stephanie Dunlap, Mary Beth Blauwet, Gary Koch, Kirkwood F. Adams
This prospective study investigated whether pretreatment with intravenously administered calcium would influence the effect of nifedipine on rest hemodynamics and treadmill performance in patients with ischemic heart disease. Seventeen patients were studied after undergoing a qualifying treadmill exercise test that revealed ST segment depression indicative of ischemic heart disease. Study subjects performed three additional treadmill tests as part of the protocol. One treadmill test was obtained from each patient to provide baseline measurements without a preceding intravenous infusion and in the absence of all antianginal drugs including nifedipine; two additional exercise tests were preceded by an infusion and 10 mg of bite-and-swallow nifedipine. The infusions, administered in a randomized, double-blind, crossover fashion, consisted of either 10 ml of 10% calcium chloride (13.6 mEq) in 50 ml of 5% dextrose in water or 5% dextrose in water alone. Rest systolic blood pressure (134 ± 4.6 mm Hg) was unchanged after placebo infusion (135 ± 4.6 mm Hg) but decreased to 124 ± 4.1 mm Hg (p < 0.01) 25 min after nifedipine administration. Rest systolic blood pressure increased after calcium infusion (from 139 ± 4.3 to 148 ± 4.8 mm Hg, p < 0.01) and then decreased significantly 25 min after nifedipine administration to 135 ± 4.2 mm Hg (p < 0.01). Despite a decrease at the time of peak nifedipine effect after either infusion, systolic blood pressure was significantly lower after administration of nifedipine alone than after administration of calcium and nifedipine (124 ± 4.1 vs. 135 ± 4.2 mm Hg, p < 0.01). Peak exercise systolic blood pressure was reduced after placebo and nifedipine (170 ± 7.5 mm Hg, p < 0.05), but not after calcium and nifedipine, in comparison with the value of 178 ± 8.2 mm Hg on the baseline treadmill test. Exercise duration was longer (p < 0.05) than baseline duration (365 ± 27 s) after placebo and nifedipine (409 ± 32 s) but was not significantly changed after calcium and nifedipine (391 ± 34 s). Maximal ST segment depression on baseline testing (1.35 ± 0.1 mm) was significantly reduced (p < 0.05) after administration of either nifedipine alone (0.79 ± 0.1 mm) or calcium and nifedipine (0.85 ± 0.2 mm). All 17 patients had ST segment depression on baseline exercise testing compared with only 12 of 17 subjects after nifedipine alone and only 10 after calcium and nifedipine. Conclusions: Calcium administration was associated with a significant increase in systolic blood pressure in patients with ischemic heart disease. Nifedipine reversed the increase in blood pressure induced by calcium but systolic pressure did not decrease below baseline values. By electrocardiographic criteria, treadmill performance was still improved compared with baseline values when administration of nifedipine was preceded by calcium.
Exercise Test
Myocardial Ischemia
Deglutition
Wohns, D. H. W., Patterson, J. H., Clarke, S., Dunlap, S., Blauwet, M. B., Koch, G., & Adams, K. F. (1991). Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine. Journal of the American College of Cardiology, 18(4), 1070-1076. https://doi.org/10.1016/0735-1097(91)90769-6
Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine. / Wohns, David H.W.; Patterson, J. Herbert; Clarke, Susan; Dunlap, Stephanie; Blauwet, Mary Beth; Koch, Gary; Adams, Kirkwood F.
In: Journal of the American College of Cardiology, Vol. 18, No. 4, 01.01.1991, p. 1070-1076.
Wohns, DHW, Patterson, JH, Clarke, S, Dunlap, S, Blauwet, MB, Koch, G & Adams, KF 1991, 'Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine', Journal of the American College of Cardiology, vol. 18, no. 4, pp. 1070-1076. https://doi.org/10.1016/0735-1097(91)90769-6
Wohns DHW, Patterson JH, Clarke S, Dunlap S, Blauwet MB, Koch G et al. Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine. Journal of the American College of Cardiology. 1991 Jan 1;18(4):1070-1076. https://doi.org/10.1016/0735-1097(91)90769-6
Wohns, David H.W. ; Patterson, J. Herbert ; Clarke, Susan ; Dunlap, Stephanie ; Blauwet, Mary Beth ; Koch, Gary ; Adams, Kirkwood F. / Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine. In: Journal of the American College of Cardiology. 1991 ; Vol. 18, No. 4. pp. 1070-1076.
@article{49797eaa6ed84f098925ddb5a0b7e2d5,
title = "Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine",
abstract = "This prospective study investigated whether pretreatment with intravenously administered calcium would influence the effect of nifedipine on rest hemodynamics and treadmill performance in patients with ischemic heart disease. Seventeen patients were studied after undergoing a qualifying treadmill exercise test that revealed ST segment depression indicative of ischemic heart disease. Study subjects performed three additional treadmill tests as part of the protocol. One treadmill test was obtained from each patient to provide baseline measurements without a preceding intravenous infusion and in the absence of all antianginal drugs including nifedipine; two additional exercise tests were preceded by an infusion and 10 mg of bite-and-swallow nifedipine. The infusions, administered in a randomized, double-blind, crossover fashion, consisted of either 10 ml of 10{\%} calcium chloride (13.6 mEq) in 50 ml of 5{\%} dextrose in water or 5{\%} dextrose in water alone. Rest systolic blood pressure (134 ± 4.6 mm Hg) was unchanged after placebo infusion (135 ± 4.6 mm Hg) but decreased to 124 ± 4.1 mm Hg (p < 0.01) 25 min after nifedipine administration. Rest systolic blood pressure increased after calcium infusion (from 139 ± 4.3 to 148 ± 4.8 mm Hg, p < 0.01) and then decreased significantly 25 min after nifedipine administration to 135 ± 4.2 mm Hg (p < 0.01). Despite a decrease at the time of peak nifedipine effect after either infusion, systolic blood pressure was significantly lower after administration of nifedipine alone than after administration of calcium and nifedipine (124 ± 4.1 vs. 135 ± 4.2 mm Hg, p < 0.01). Peak exercise systolic blood pressure was reduced after placebo and nifedipine (170 ± 7.5 mm Hg, p < 0.05), but not after calcium and nifedipine, in comparison with the value of 178 ± 8.2 mm Hg on the baseline treadmill test. Exercise duration was longer (p < 0.05) than baseline duration (365 ± 27 s) after placebo and nifedipine (409 ± 32 s) but was not significantly changed after calcium and nifedipine (391 ± 34 s). Maximal ST segment depression on baseline testing (1.35 ± 0.1 mm) was significantly reduced (p < 0.05) after administration of either nifedipine alone (0.79 ± 0.1 mm) or calcium and nifedipine (0.85 ± 0.2 mm). All 17 patients had ST segment depression on baseline exercise testing compared with only 12 of 17 subjects after nifedipine alone and only 10 after calcium and nifedipine. Conclusions: Calcium administration was associated with a significant increase in systolic blood pressure in patients with ischemic heart disease. Nifedipine reversed the increase in blood pressure induced by calcium but systolic pressure did not decrease below baseline values. By electrocardiographic criteria, treadmill performance was still improved compared with baseline values when administration of nifedipine was preceded by calcium.",
author = "Wohns, {David H.W.} and Patterson, {J. Herbert} and Susan Clarke and Stephanie Dunlap and Blauwet, {Mary Beth} and Gary Koch and Adams, {Kirkwood F.}",
journal = "Journal of the American College of Cardiology",
T1 - Influence of calcium administration on the short-term hemodynamic and anti-ischemic effects of nifedipine
AU - Wohns, David H.W.
AU - Patterson, J. Herbert
AU - Clarke, Susan
AU - Dunlap, Stephanie
AU - Blauwet, Mary Beth
AU - Koch, Gary
AU - Adams, Kirkwood F.
N2 - This prospective study investigated whether pretreatment with intravenously administered calcium would influence the effect of nifedipine on rest hemodynamics and treadmill performance in patients with ischemic heart disease. Seventeen patients were studied after undergoing a qualifying treadmill exercise test that revealed ST segment depression indicative of ischemic heart disease. Study subjects performed three additional treadmill tests as part of the protocol. One treadmill test was obtained from each patient to provide baseline measurements without a preceding intravenous infusion and in the absence of all antianginal drugs including nifedipine; two additional exercise tests were preceded by an infusion and 10 mg of bite-and-swallow nifedipine. The infusions, administered in a randomized, double-blind, crossover fashion, consisted of either 10 ml of 10% calcium chloride (13.6 mEq) in 50 ml of 5% dextrose in water or 5% dextrose in water alone. Rest systolic blood pressure (134 ± 4.6 mm Hg) was unchanged after placebo infusion (135 ± 4.6 mm Hg) but decreased to 124 ± 4.1 mm Hg (p < 0.01) 25 min after nifedipine administration. Rest systolic blood pressure increased after calcium infusion (from 139 ± 4.3 to 148 ± 4.8 mm Hg, p < 0.01) and then decreased significantly 25 min after nifedipine administration to 135 ± 4.2 mm Hg (p < 0.01). Despite a decrease at the time of peak nifedipine effect after either infusion, systolic blood pressure was significantly lower after administration of nifedipine alone than after administration of calcium and nifedipine (124 ± 4.1 vs. 135 ± 4.2 mm Hg, p < 0.01). Peak exercise systolic blood pressure was reduced after placebo and nifedipine (170 ± 7.5 mm Hg, p < 0.05), but not after calcium and nifedipine, in comparison with the value of 178 ± 8.2 mm Hg on the baseline treadmill test. Exercise duration was longer (p < 0.05) than baseline duration (365 ± 27 s) after placebo and nifedipine (409 ± 32 s) but was not significantly changed after calcium and nifedipine (391 ± 34 s). Maximal ST segment depression on baseline testing (1.35 ± 0.1 mm) was significantly reduced (p < 0.05) after administration of either nifedipine alone (0.79 ± 0.1 mm) or calcium and nifedipine (0.85 ± 0.2 mm). All 17 patients had ST segment depression on baseline exercise testing compared with only 12 of 17 subjects after nifedipine alone and only 10 after calcium and nifedipine. Conclusions: Calcium administration was associated with a significant increase in systolic blood pressure in patients with ischemic heart disease. Nifedipine reversed the increase in blood pressure induced by calcium but systolic pressure did not decrease below baseline values. By electrocardiographic criteria, treadmill performance was still improved compared with baseline values when administration of nifedipine was preceded by calcium.
AB - This prospective study investigated whether pretreatment with intravenously administered calcium would influence the effect of nifedipine on rest hemodynamics and treadmill performance in patients with ischemic heart disease. Seventeen patients were studied after undergoing a qualifying treadmill exercise test that revealed ST segment depression indicative of ischemic heart disease. Study subjects performed three additional treadmill tests as part of the protocol. One treadmill test was obtained from each patient to provide baseline measurements without a preceding intravenous infusion and in the absence of all antianginal drugs including nifedipine; two additional exercise tests were preceded by an infusion and 10 mg of bite-and-swallow nifedipine. The infusions, administered in a randomized, double-blind, crossover fashion, consisted of either 10 ml of 10% calcium chloride (13.6 mEq) in 50 ml of 5% dextrose in water or 5% dextrose in water alone. Rest systolic blood pressure (134 ± 4.6 mm Hg) was unchanged after placebo infusion (135 ± 4.6 mm Hg) but decreased to 124 ± 4.1 mm Hg (p < 0.01) 25 min after nifedipine administration. Rest systolic blood pressure increased after calcium infusion (from 139 ± 4.3 to 148 ± 4.8 mm Hg, p < 0.01) and then decreased significantly 25 min after nifedipine administration to 135 ± 4.2 mm Hg (p < 0.01). Despite a decrease at the time of peak nifedipine effect after either infusion, systolic blood pressure was significantly lower after administration of nifedipine alone than after administration of calcium and nifedipine (124 ± 4.1 vs. 135 ± 4.2 mm Hg, p < 0.01). Peak exercise systolic blood pressure was reduced after placebo and nifedipine (170 ± 7.5 mm Hg, p < 0.05), but not after calcium and nifedipine, in comparison with the value of 178 ± 8.2 mm Hg on the baseline treadmill test. Exercise duration was longer (p < 0.05) than baseline duration (365 ± 27 s) after placebo and nifedipine (409 ± 32 s) but was not significantly changed after calcium and nifedipine (391 ± 34 s). Maximal ST segment depression on baseline testing (1.35 ± 0.1 mm) was significantly reduced (p < 0.05) after administration of either nifedipine alone (0.79 ± 0.1 mm) or calcium and nifedipine (0.85 ± 0.2 mm). All 17 patients had ST segment depression on baseline exercise testing compared with only 12 of 17 subjects after nifedipine alone and only 10 after calcium and nifedipine. Conclusions: Calcium administration was associated with a significant increase in systolic blood pressure in patients with ischemic heart disease. Nifedipine reversed the increase in blood pressure induced by calcium but systolic pressure did not decrease below baseline values. By electrocardiographic criteria, treadmill performance was still improved compared with baseline values when administration of nifedipine was preceded by calcium.
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology


text:
Arts & Crafts - Childrens
Quick Links... Arts & Crafts - Childrens Computer Coding & Programming Cookery Classes - Childrens Dancewear & Dance Shoes - Childrens Drama Classes - Childrens Sun & UV Protection Wear - Babies & Childrens Touch Typing - Childrens
Children's Party Entertainers in Humberside
Children's party entertainers for all ages from 1st birthday to teens. There are a variety of themes including magicians, jugglers and clowns as well as princess parties, fairy parties and superhero parties. Parties with a difference include animal parties, film making parties, skateboarding, football and other sports themed parties and fashion parties where guests learn how to design and make their own unique items!
Animal Antics
Take a walk on the wildside with us for that unforgettable Birthday Party / School Visit / Summer fete.
Meet a variety of tactile animals from Giant Bugs and Reptiles to Birds Of Prey. Based in the West Midlands but offering a Nationwide Service.
Phone John on 01902 678320 for more information.
Children's animal party entertainers
Category: Children's Party Entertainers
Rugbytots
The World's favourite rugby play programme
Rugbytots is the World's favourite rugby play programme.
We run over 2000 classes a week throughout the UK introducing children from the ages of 2-7 to rugby in a fun, safe and structured environment.
Our classes are split into three age groups: 2-3½ years, 3½-5 years and 5-7 years.
Rugby coaching for toddlers and young children in Aberdeen, Angus, Bedfordshire, Berkshire, Birmingham, Bristol, Buckinghamshire, Cambridgeshire, Carmarthenshire, Central London, Cheshire, Cornwall, County Durham, Cumbria, Derbyshire, Devon, Dorset, East Ayrshire, East London, East Sussex, Edinburgh, Essex, Fife, Glasgow, Gloucestershire, Greater London, Greater Manchester, Halifax, Hampshire, Hastings, Herefordshire, Hertfordshire, Humberside, Isle of Wight, Jersey, Kent, Lancashire, Leicestershire, Lincolnshire, Manchester, Merseyside, Mid Lothian, Norfolk, North London, North West London, North Yorkshire, Northamptonshire, Northern Ireland, Northumberland, Nottinghamshire, Oxfordshire, Perth & Kinross, Renfrewshire, Rye, Scottish Borders, Shropshire, Somerset, North Somerset, South East London, South Gloucestershire, South London, South Wales, South West London, South Yorkshire, Staffordshire, Stirling, Suffolk, Surrey, Tenterden, Tyne & Wear, Warwickshire, West Kent, West London, West Midlands, West Sussex, West Yorkshire, Wiltshire, Worcestershire and Wrexham
Smart Raspberry Cookery School
Online and in-class Cookery Classes for Girls and Boys
Smart Raspberry specialises in providing cookery classes and workshops to children as young as 5 years up to teenagers. We run classes during term time and the school holidays as well as workshops, parties, Duke of Edinburgh courses and more. We are now offering franchising opportunities nationwide. For more information please go to the franchise page: https://www.smartraspberry.com/franchise-opportunities/
Extra-Curricular Classes
"Such a popular extracurricular activity, extremely well organised; they are run by dedicated, enthusiastic staff who are educating our children in cookery skills and widening their horizons! First Class!" Rob Harmer, Headteacher at St Marys School, Henley-on-Thames
Open Classes – Weekends and Holidays
The Best Club ever!!!! That's how my daughter describes Smart Raspberry Cookery School. The Saturday morning and holiday clubs have taught my daughter how to cook a vast array of sweet and savoury dishes, which has increased her confidence and taught her to be responsible around the kitchen. The recipes are easy to follow and so good I have actually continued to use them myself, definitely recommended!!" Rachel Foreman, Parent
Workshops in Schools
"We recently worked with Smart Raspberry for our discovery week. Our theme was Mind, Body and Soul. We were given amazing options for our cooking class and they were able to work with our date and time constraints. In the end, we chose smoothies and a noodle salad. All of the students choose the cooking class as a highlight of their week. The food was delicious and many students reported later that they had made them on their own at home. Overall a great success. The end result included happy and full students! Highly recommend!" Mercedes Savage, ACS Hillingdon International School
"My daughter had the Smart Raspberry cupcake party for her 8th birthday. It was fantastic and all the girls loved it – the cake making, the icing (with an animal theme) and eating the final product! One of her friends needed an egg-free version and her Mum said they were the best egg-free cakes she had ever tasted! I would thoroughly recommend Smart Raspberry for an exciting and hassle-free party" Karen, Parent
Children's cookery classes in Amersham, Beaconsfield, Chesham, Denham, Gerrards Cross, Great Missenden, High Wycombe, Slough, Dunstable, Leighton Buzzard, Luton, Harefield, Hayes, Hillingdon, Northwood, Ruislip, Uxbridge and West Drayton, Ascot, Bracknell, Reading, Slough, Windsor, Wokingham, Milton Keynes, Newport Pagnell, Olney, Stony Stratford, Bletchley, Winslow, Woburn Sands, Aylesbury, Haddenham, Wendover, Princes Risborough, Thame, Marlow, Maidenhead, Henley-on-Thames, Ilford, Loughton, Epping, Woodford, Chigwell, West London, Ealing, Acton, Chiswick, Hammersmith, Sutton, Epsom, Ewell


It is my great pleasure to get to work with the Huichol people in the production of HUICHOL LOVE jewelry.
Within the rugged mountains of the Sierra Madre Occidental, the Huichol Center empowers both Huichol individuals and communities across the country to maintain their spiritual, artistic and cultural heritage by preparing them to coexist with the outside world on their own terms. Facing territorial encroachment of their sacred land and a need to survive in a modern world, the Huichol Center provides a bridge across a cultural divide. With careful planning and education the Huichol people can thrive in today's world without sacrificing their native traditions or language.
The Huichol Center provides work for the Huicholes that utilizes their traditional skills and a school for the Huichol children.
They grow fruits and vegetables in their organic gardens and raise chickens, rabbits, and turkeys to help sustain the community.
They are archiving all things Huichol: Huichol art, rituals, traditional symbols, language, etc.


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Watch Mahler 5 from the Opening Gala Concert
[Sorry, our license to post the archived video of this concert has expired.]
On September 19, we launched our 2017–18 season with a concert saluting the virtuosos who make up the New York Philharmonic. They performed Mahler's Symphony No. 5, led by Music Director Designate Jaap van Zweden.
It was broadcast live on Facebook, the Philharmonic's fourth live concert broadcast on that medium. Hosted by Alec Baldwin, the broadcast takes you inside the hall for a complete performance of Mahler's Fifth and a chance to meet our new President and CEO, Deborah Borda.
Enjoy this archive video of the broadcast, which will be available for 45 days.
Tags: Mahler
PHOTOS: 176th Season Opening Gala Concert
Posted September 20, 2017 in photos-and-slideshows
The musicians of the New York Philharmonic were the honorees of 106 All-Stars: Opening Gala Concert of New York's Orchestra. Conducted by Music Director Designate Jaap van Zweden, the 106 All-Stars performed Mahler's Fifth Symphony in a concert broadcast on Facebook Live, hosted by Alec Baldwin. The Gala also included a star-studded red carpet, buzzing cocktail reception, and glamorous dinner.
Tags: Jaap van Zweden Opening Gala Mahler
Something's Coming: Bernstein's Philharmonic: A Centennial Festival
Calling all Bernstein lovers! The Philharmonic is celebrating Lenny's 100th birthday with Bernstein's Philharmonic: A Centennial Festival (October 25–November 14) plus other events throughout the season — concerts, education activities, a Mahler marathon, and more — befitting the renowned composer, conductor, pianist, and educator who served as our Music Director (1958–69) and then Laureate Conductor.
Festival highlights include:
• Bernstein-successor Alan Gilbert and Bernstein-protégé Leonard Slatkin leading Bernstein's complete symphonies, with Jeremy Irons as speaker in the Kaddish Symphony, plus music by Gershwin and more (details here for the first program, second program, and third program)
• An all-Bernstein Young People's Concert — the series that Bernstein famously brought to national attention through the TV broadcasts
• Harvard and University of Michigan students studying Bernstein as an educator and conductor, and interviewing Philharmonic audience members who attended Bernstein's Young People's Concerts as children
• Leonard Bernstein: The Philharmonic's First American Voice, an archival exhibit featuring original material from the Philharmonic Archives
• The free Insights at the Atrium event "Inside the Orchestra: Working with Bernstein," featuring Philharmonic musicians past and present reflecting on Bernstein as conductor and colleague
Later in the season, the tributes include performances plus the free event "Bernstein's Mahler Marathon: The Sony Recordings," 13 hours of Bernstein's performances of his Philharmonic predecessor's complete symphonies, and collaborations with the New York Public Library for the Performing Arts.
To quote the man himself: "It's been a family association in many ways, and even though faces change, the entity, the totality of the New York Philharmonic remains solid, and I remain bound to it by mysterious cords which tie me to the orchestra as long as I live. In some funny, spiritual sense, they will always be my orchestra, no matter who else's orchestra they may be."
Tags: leonard bernstein Mahler Young People's Concerts
Mahler Comes Home to Vienna
Music Director Alan Gilbert, soprano Christina Landshamer, and the New York Philharmonic rehearsed Mahler's ethereal Symphony No. 4 on March 30 in the Wiener Konzerthaus, in the city that the composer and former New York Philharmonic Music Director called home. This appearance on the EUROPE / SPRING 2017 tour marks Gilbert's final Philharmonic performance in the Austrian capital as Music Director.
(Video: Chris Lee)
Tags: EUROPE / SPRING 2017 Mahler
New York Philharmonic Presents Leonard Bernstein's Marked Mahler Score to Vienna Philharmonic
This morning in Vienna, the New York Philharmonic and the family of Leonard Bernstein presented the Vienna Philharmonic with Bernstein's marked score of Mahler's Das Lied von der Erde, in celebration of the Austrian orchestra's 175th birthday. Above: New York Philharmonic Archivist / Historian Barbara Haws; Andreas Grossbauer, President (and violin) of the Vienna Philharmonic; and Wolfgang Plank, Director of Archives (and oboe) of the Vienna Philharmonic, at the Vienna Philharmonic's new Archives.
Following his 1966 Vienna Philharmonic debut, Bernstein kept the score, which he had obtained from the Vienna Philharmonic's Archives. He treasured it for the rest of his life; on his death it was transferred to the New York Philharmonic Archives as part of the collection of his marked conducting scores.
The New York Philharmonic and Vienna Philharmonic are both celebrating their 175th anniversaries this season. The New York Philharmonic presented the gift at the Vienna opening of Vienna and New York: 175 Years of Two Philharmonics, a joint exhibit of archival material drawn from both orchestras' histories that will be on display at Vienna's Haus der Musik until January 2018 (having previously been displayed at the Austrian Cultural Forum in New York).
Explore a virtual tour of the exhibition from when it was on view in New York.
(Photo: Wiener Philharmoniker, Terry Linke)
Tags: vienna archives leonard bernstein Mahler 175th Anniversary Season
Alan Gilbert To Conduct Philharmonic Joined by Musicians from Around the World, Celebrating Music's Power to Unite
Alan Gilbert and the New York Philharmonic believe in the power of music to heal, build bridges, and unite across borders. From the free performance of Mahler's Resurrection Symphony on the tenth anniversary of 9/11 and performing at the United Nations this past December to historic tours and deep international partnerships, the Orchestra and Alan Gilbert have long used music to make the world a better place.
In his final subscription program, Alan Gilbert will lead the New York Philharmonic joined by musicians from orchestras around the world in concerts showcasing the universal language of music.
Alan Gilbert Season Finale: A Concert for Unity, June 8–10, will feature Gilbert conducting the Orchestra and musicians the Philharmonic has invited from orchestras in Australia, Brazil, China, Cuba, Czech Republic, France, Germany, Iran, Iraq, Israel, Japan, Lebanon, Mexico, Russia, South Africa, South Korea, Turkey, Venezuela, the United Kingdom, and the United States in Mahler's Symphony No. 7.
Yo-Yo Ma (June 8) and Wynton Marsalis (June 9), two close friends of the Philharmonic who share a deep commitment to musical humanism, will appear as special guest artists.
The concerts will launch a new initiative to be led by Alan Gilbert following his tenure as Philharmonic Music Director in which musicians from around the world will come together to perform music at critical times in support of peace, development, and human rights.
(Photo: Chris Lee)
Tags: Alan Gilbert's Farewell Season Mahler
Philharmonic and Jaap van Zweden To Open Mahler Festival 2020, Presented by The Royal Concertgebouw
This just in: Mahler and the Philharmonic will continue to groove in 2020. Today it was announced that the Philharmonic and Jaap van Zweden, who becomes Music Director in 2018, will open the Mahler Festival — held every 25 years — in Amsterdam in May 2020, presented by The Royal Concertgebouw. They'll perform Mahler's Symphony No. 1 in the festival's opening concert in the Concertgebouw, part of the Orchestra's first European tour with Jaap van Zweden in spring 2020.
2020 will mark 100 years since the first Mahler Festival, honoring the 25th anniversary of legendary conductor Willem Mengelberg as chief conductor of the Concertgebouw Orchestra. The Philharmonic enjoys a special connection with both Mahler and Mengelberg: they both served as Music Directors, and Mahler conducted several of his own works with the Philharmonic, including the U.S. Premiere of his Symphony No. 1 in 1909.
The Mahler Festival 2020 will include performances of all of Mahler's symphonies played by the New York Philharmonic, Vienna Philharmonic, Berlin Philharmonic, and Royal Concertgebouw Orchestra — all of which Mahler himself conducted and which will be heard together in Amsterdam for the first time.
Photo by Chris Lee: Philharmonic President Matthew VanBesien, future Music Director Jaap van Zweden, and Concertgebouw General Manager Simon Reinink
Tags: Jaap van Zweden Mahler
Mahler Wundersingers: Des Knaben Wunderhorn Philharmonic Soloists
Posted May 13, 2016 in concert-and-performance-buzz
This week's concerts feature Mahler's Des Knaben Wunderhorn, which the New York Philharmonic first performed in 1910, when Alma Gluck sang the American premiere of "Rheinlegendchen" (one of the songs in the collection) with the composer, who was the Philharmonic's Music Director at the time, at the podium.
The New York Philharmonic Archives created a digital exhibit of all Philharmonic Des Knaben Wunderhorn soloists, from 1910 to the present, interspersed with various "wunderhorns" found in the Archives' collection of glass lantern slides.
Tags: archives Mahler
Concerts in the Parks (25)
music of conscience (1)
Jaap van Zweden (17)
Deborah Borda (3)
What's New at Lincoln Center (22)
zarin mehta fellows (16)
Mahler (12)
Alec Baldwin (11)
Very Young Composers (12)
esa-pekka salonen (5)
slideshows (34)
Richard Strauss (4)
THE ART OF THE SCORE (10)
Yo-Yo Ma (6)