Abstract—In the future communication applications, users
may obtain their messages that have different importance levels
distributively from several available sources, such as distributed
storage or even devices belonging to other users. This
scenario is the best modeled by the multilevel diversity coding
systems (MDCS). To achieve perfect (information-theoretic)
secrecy against wiretap channels, this paper investigates the
fundamental limits on the secure rate region of the asymmetric
MDCS (AMDCS), which include the symmetric case as a special
case. Threshold perfect secrecy is added to the AMDCS model.
The eavesdropper may have access to any one but not more than
one subset of the channels but know nothing about the sources,
as long as the size of the subset is not above the security level.
The question of whether superposition (source separation) coding
is optimal for such an AMDCS with threshold perfect secrecy
is answered. A class of secure AMDCS (S-AMDCS) with an
arbitrary number of encoders is solved, and it is shown that linear
codes are optimal for this class of instances. However, in contrast
with the secure symmetric MDCS, superposition is shown to
be not optimal for S-AMDCS in general. In addition, necessary
conditions on the existence of a secrecy key are determined as a
design guideline.
function [R,k,b] = msc(A)
% 多元散射校正
% 輸入待處理矩陣,通過多元散射校正,求得校正后的矩陣
%% 獲得矩陣行列數
[m,n] = size(A);
%% 求平均光譜
M = mean(A,2);
%% 利用最小二乘法求每一列的斜率k和截距b
for i = 1:n
a = polyfit(M,A(:,i),1);
if i == 1
k = a(1);
b = a(2);
else
k = [k,a(1)];
b = [b,a(2)];
end
end
%% 求得結果
for i = 1:n
Ai = (A(:,i)-b(i))/k(i);
if i == 1
R = Ai;
else
R = [R,Ai];
end
end
transimpedance linearization circuitry. This allows it to drive
video loads with excellent differential gain and phase perfor
mance on only 50 mW of power. The AD8001 is a current
feedback amplifier and features gain flatness of 0.1 dB to 100 MHz
while offering differential gain and phase error of 0.01% and
0.025°. This makes the AD8001 ideal for professional video
electronics such as cameras and video switchers. Additionally,
the AD8001’s low distortion and fast settling make it ideal for
buffer high-speed A-to-D converters.
The AD8001 offers low power of 5.5 mA max (VS = ±5 V) and
can run on a single +12 V power supply, while being capable of
delivering over 70 mA of load current. These features make this
amplifier ideal for portable and battery-powered applications
where size and power are critical.
The outstanding bandwidth of 800 MHz along with 1200 V/μs
of slew rate make the AD8001 useful in many general purpose
high-speed applications where dual power supplies of up to ±6 V
and single supplies from 6 V to 12 V are needed. The AD8001 is
available in the industrial temperature range of –40°C to +85°C.
From the transition of analog to digital communication along with seamless mobility and
high computing power of small handheld devices, the wireless communications industry has
seen tremendous changes leading to the integration of several telecommunication networks,
devices and services over last 30 years. The rate of this progress and growth has increased
particularly in the past decade because people no longer use their devices and networks for
voice only, but demand bundle contents such as data download/streaming, HDTV, HD video ,
3D video conferencing with higher efficiency, seamless connectivity, intelligence, reliability
and better user experience. Although the challenges facing service providers and
telecommunication companies differ by product, region, market size, and their areas of
concentration but time to market, efficient utilization of their assets and revenue expansion,
have impacted significantly how to manage and conduct their business while maintaining
sufficient margin.
During the past two decades, technological development related to telecommuni-
cation technologies has allowed organizations of all types and size to be able to de-
velop effective networking applications in support of information management. Fur-
thermore, telecommunication technologies combined with computer technology have
created the foundation of modern information technology which has affected all as-
pects of societal and organizational functions in our modern world.
This book was born from the perception that there is much more to spectrum use
and sharing than one sees reflected in publications, whether academic, commercial
or political. the former – in good research style – tend towards reductionism and
concentrate on specific, detailed aspects. commercial publications tend to empha-
size the positive aspects and they tend to put promise above practice. Given the ever
increasing pace of technology development and recent successes of new wireless
technologies, some pundits predict large-scale spectrum scarcity, potentially lead-
ing to economic catastrophe. Although economic theory has a hard time explaining
recent events that shook the world economy, the notion of spectrum scarcity is intui-
tively acceptable, even if not correct or immediately relevant.
In the seven years since the first edition of this book was completed, Electrostatic
Discharge (ESD) phenomena in integrated circuits (IC) continues to be important
as technologies shrink and the speed and size of the chips increases. The phenom-
ena related to ESD events in semiconductor devices take place outside the realm of
normal device operation. Hence, the physics governing this behavior are not typ-
ically found in general textbooks on semiconductors.