SYNCHRONIZATION OF LORENZ SYSTEMS VIA IMPULSIVE CONTROL AND SPORADIC COUPLING

2004 ◽  
Vol 14 (08) ◽  
pp. 2963-2969 ◽  
Author(s):  
K. LI ◽  
Y. C. SOH ◽  
Z. G. LI
Keyword(s):  
Secure Communication ◽  
Communication Systems ◽  
Impulsive Control ◽  
Time Interval ◽  
Secure Communications ◽  
Bandwidth Utilization ◽  
Channel Bandwidth ◽  
Time Required

In this paper, a method that combines impulsive control and sporadic coupling for the synchronization of two Lorenz systems is proposed. The time required to synchronize the Lorenz systems can be readily computed. With this scheme, the Lorenz systems can be synchronized quickly and the time interval between successive impulsive signals can be made larger. This will improve the efficiency of channel bandwidth utilization when applied to secure communications. The results obtained in this paper are very useful in the applications of chaos-based secure communication systems.

SYNCHRONIZATION THEOREM FOR A CHAOTIC SYSTEM

1995 ◽  
Vol 05 (01) ◽  
pp. 297-302 ◽  
Author(s):  
JÖRG SCHWEIZER ◽  
MICHAEL PETER KENNEDY ◽  
MARTIN HASLER ◽  
HERVÉ DEDIEU
Keyword(s):  
Lyapunov Function ◽  
Lyapunov Exponents ◽  
Chaotic System ◽  
Secure Communication ◽  
Communication Systems ◽  
Chaotic Systems ◽  
Secure Communications ◽  
Error Feedback ◽  
Response System ◽  
Synchronization Method

Since Pecora & Carroll [Pecora & Carroll, 1991; Carroll & Pecora, 1991] have shown that it is possible to synchronize chaotic systems by means of a drive-response partition of the systems, various authors have proposed synchronization schemes and possible secure communications applications [Dedieu et al., 1993, Oppenheim et al., 1992]. In most cases synchronization is proven by numerically computing the conditional Lyapunov exponents of the response system. In this work a new synchronization method using error-feedback is developed, where synchronization is provable using a global Lyapunov function. Furthermore, it is shown how this scheme can be applied to secure communication systems.

scholarly journals HIGH QUALITY LOW BITRATE VOICE CODEC FOR TRANSMISSION OVER ADVANCED LTE

2021 ◽  
Vol 1 (1) ◽  
pp. 83-93
Author(s):  
Noor N. Edan ◽  
Nasser N. Khamiss
Keyword(s):  
Communication Systems ◽  
Linear Prediction ◽  
Voice Quality ◽  
Open Loop ◽  
Spatial Multiplexing ◽  
Bandwidth Utilization ◽  
Available Bandwidth ◽  
Voice Signal ◽  
Channel Bandwidth ◽  
The Voice

In mobile communication systems bit-rate reductions while maintaining an acceptable voice quality are necessary to achieve efficiency in channel bandwidth utilization and users satisfaction. As Long-Term Evolution(LTE) converging towards all-IP solutions and supporting VOIP service, the voice signals are converted into coded digital bit-stream and sent over the network. This paper proposes the implementation of codebook excited linear prediction (CELP) voice codec algorithm based on two source-rates of low 9.6Kbps and medium 16Kbps for achieving a perceptible level of voice quality, while efficiently using available bandwidth during the transmission over advanced LTE. The architecture of proposed CELP codec model is implemented to decompose the voice signal into a set of parameters that characterize each particular frame at the encoder part, these parameters are quantized and encoded for transmission to the decoder. The investigation showed that the configuration of the link and the applied CELP codec mode mainly influence on the obtained voice capacity and quality. The quantifying also shows that the voice quality can be traded for the enhanced capacity, since the low rate codec will produce lower voice quality than higher rate codec. Also, this paper is achieved, during theconfiguration of the system with higher channel quality indicator (CQI) index, increasing in the capacity gain to a saturated value of about 500 and 1000 users per cell over 5MHz bandwidth for transmit diversity (TD) and Open-Loop Spatial Multiplexing (OLSM) respectively and up to 1000 and 2000 users per cell over 10MHz channel bandwidth for TD and OLSM respectively.

APPLICATION OF ICA–EEMD TO SECURE COMMUNICATIONS IN CHAOTIC SYSTEMS

2012 ◽  
Vol 23 (04) ◽  
pp. 1250028 ◽  
Author(s):  
SHIH-LIN LIN ◽  
PI-CHENG TUNG ◽  
NORDEN E. HUANG
Keyword(s):  
White Noise ◽  
Secure Communication ◽  
Communication Systems ◽  
Chaotic Systems ◽  
Gaussian White Noise ◽  
Secure Communications ◽  
Original Message ◽  
Mixture Of Gaussian

We propose the application of ICA–EEMD to secure communication systems. ICA–EEMD is employed to retrieve the message data encrypted by a mixture of Gaussian white noise and chaotic noise. The results showed that ICA–EEMD can effectively extract the two original message data.

scholarly journals Reversible logic in pipelined low power vedic multiplier

2019 ◽  
Vol 16 (3) ◽  
pp. 1265
Author(s):  
Ansiya Eshack ◽  
S. Krishnakumar
Keyword(s):  
Low Power ◽  
Communication Systems ◽  
Large Scale ◽  
Optical Computing ◽  
Digital Signal ◽  
Logic Gates ◽  
Reversible Logic ◽  
Large Scale Integration ◽  
Time Required ◽  
Scale Integration

<span>With an ever growing demand for low-power devices, it is a general trend to search for ways to reduce the power consumption of a system. Multipliers are an important requirement in applications linked to Digital Signal Processing, Communication Systems, Optical Computing, Nanotechnology, Low-Power Very Large Scale Integration and Quantum Computing. Conventional mathematics makes multiplication a very long and time consuming process. The use of Vedic mathematics has led to great reduction in the time required for such calculations. The excessive use of Urdhava Tiryakbhyam sutra in multiplication surely proves its effectiveness and simplicity in this domain. This sutra supports the process of pipelining, a method employed in reduction of the power used by a system. Reversible logic has been gaining demand due to its low-power capabilities and is currently being used in many computing applications. The paper proposes two multiplier systems: one design employs the Urdhava Tiryakbhyam sutra along with pipelining and the second uses reversible logic gates into the first design. These proposed systems provide very less delay for result computation and low hardware utilization when compared to non-pipelined Vedic multipliers.</span>

scholarly journals Delay in presentation of acute ischemic stroke in Lahore General Hospital, Lahore

2016 ◽  
Vol 11 (3) ◽  
Author(s):  
Rafiq A Basharat ◽  
Kamran Rashid Mirza ◽  
Muhammad Yousuf Qamar
Keyword(s):  
Emergency Department ◽  
Ischemic Stroke ◽  
Ct Scan ◽  
Acute Ischemic Stroke ◽  
General Hospital ◽  
Clinical History ◽  
Clinical Findings ◽  
Study Data ◽  
Time Interval ◽  
Time Required

Objectives: To find out the time interval from onset of the symptoms to admission in the hospital of patients suffering from acute ischemic stroke, in order to assess the feasibility of thrombolytic therapy in Lahore General Hospital. Design: Hospital-based, prospective and observational study Setting: Lahore General Hospital Lahore. Duration: Six months from January - June 2004. Patients: Seventy two patients with acute ischemic stroke diagnosed on basis of clinical findings and CT scan. Methods: Patients o f a cute ischemic stroke including cerebral infarct, T IA, venous infarct and lacunar infarct were diagnosed on basis of clinical history, examination and CT scan and enrolled in the study. Data was collected on a Performa. Time taken by patients to reach hospital after onset of symptoms, distance of patients` residences from hospital, education level of patients and time required to do a CT scan after arrival of patient in hospital were studied. Results: 54.2% were male and mean age of patients was 60 years. 58 patients had cerebral infarction, TIA`s and venous infarction were 8 and 6 respectively. Delay in presentation was divided in three groups. Within three hours (hrs) 15 (21%) patients arrived. 54 and 18 patients arrived in 3-- 24 hrs group and >24 firs group. Mean distance was roughly 44 km. Mean distance for 0-3hrs, 3-24hrs and >24hrs group was 14, 35, and 85 Km respectively. Average time required to do CT scan was nine hours after arrival of patient in emergency department. Sixty-five percent of patients coming were illiterate. Conclusion: Majority of the patients with ischemic stroke present late to. emergency department. Many factors including distance from hospital, illiteracy, non-availability of ambulance services responsible for it. Evaluation-of patients and provision of urgent CT scan is required. in hospitals.

Efficient JPEG Encoding Using Bernoulli Shift Map for Secure Communication

2021 ◽  
Author(s):  
Nisar Ahmad ◽  
Muhammad Usman Younus ◽  
Muhammad Rizwan Anjum ◽  
Gulshan Saleem ◽  
Zaheer Ahmed Gondal ◽  
...  
Keyword(s):  
Secure Communication ◽  
Communication Systems ◽  
Bernoulli Shift ◽  
Random Number Generator ◽  
Lossless Compression ◽  
Jpeg Compression ◽  
Digital Data ◽  
Compression Scheme ◽  
Encrypt Data ◽  
Shift Map

Abstract Digital data must be compressed and encrypted to maintain confidentiality and efficient bandwidth usage. These two parameters are essential for information processing in most communication systems. Image compression and encryption may result in reduced restoration quality and degraded performance. This study attempts to provide a compression and encryption scheme for digital data named as Secure-JPEG. This scheme is built on the JPEG compression format, the most widely used lossy compression scheme. It extends the standard JPEG compression algorithm to encrypt data during compression. Secure-JPEG scheme provides encryption along with the process of compression, and it could be altered easily to provide lossless compression. On the other hand, the lossless compression provides less compression ratio and is suitable only in specific scenarios. The paper address the problem of security lacks due to the use of a simple random number generator which can not be cryptographically secure. The improved security characteristics are provided through Generalized Bernoulli Shift Map, which has a chaotic system with demonstrated security. The algorithm's security is tested by several cryptographic tests and the chaotic system’s behavior is also analyzed.

Security Policies a Formal Environment for a Test Cases Generation

2019 ◽  
pp. 237-264
Author(s):  
Ryma Abassi ◽  
Sihem Guemara El Fatmi
Keyword(s):  
Secure Communication ◽  
Communication Systems ◽  
Security Policy ◽  
System Modeling ◽  
Test Cases ◽  
Model Checker ◽  
Specification Test ◽  
Security Strategy ◽  
Testing Tools ◽  
Test Objective

Specifying a security policy (SP) is a challenging task in the development of secure communication systems since it is the bedrock of any security strategy. Paradoxically, this specification is error prone and can lead to an inadequate SP regarding the security needs. Therefore, it seems necessary to define an environment allowing one to “trust” the implemented SP. A testing task aims verifying whether an implementation is conforming to its specification. Test is generally achieved by generating and executing test cases. Some automated testing tools can be used from which model checkers. In fact, given a system modeling and a test objective, the model checker can generate a counterexample from which test cases can be deduced. The main proposition of this chapter is then a formal environment for SP test cases generation based on a system modeling, a SP specification (test purpose), and the use of a model checker. Once generated, these test cases must be improved in order to quantify their effectiveness to detect SP flaws. This is made through the generation of mutants.

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