scholarly journals Three-Level Delta Modulation for Laplacian Source Coding

2017 ◽  
Vol 17 (1) ◽  
pp. 95-102 ◽  
Author(s):  
B. DENIC ◽  
Z. PERIC ◽  
V. DESPOTOVIC
2014 ◽  
Vol 14 (1) ◽  
pp. 1-12
Author(s):  
Didik Ardiyanto ◽  
Bambang Hari Purwoto

Kompresi citra merupakan suatu teknik yang digunakan untuk mengurangi biaya penyimpanan dan transmisi. Pemampatan atau kompresi citra merupakan suatu metode yang sangat bermanfaat bagi perkembangan citra digital. Dengan kompresi, data citra digital yang ukurannya besar, dapat dikompres sehingga mempunyai ukuran yang lebih kecil. Program kompresi citra dengan metode delta modulation ini, dibuat dengan GUI dan source coding. Dengan menerapkan fungsi dari Dmsig untuk pengolahan sinyal, maka didapatkan rumus untuk mengkompres gambar yang dipengaruhi oleh step size dan ukuran gambar tersebut. Kelebihan dari teknik Delta Modulation adalah dapat mengkompres gambar grayscale, black and white dan true color. Hasil gambar yang sudah dikompres menunjukkan bahwa metode ini baik untuk menghasilkan gambar dengan output berformat jpg,png dan tiff. Kualitas gambar yang paling baik dari hasil kompresi delta modulation yaitu gambar berformat jpg. Untuk tingkat kompresi yang paling bagus juga ada pada gambar berformat jpg, ini diambil berdasarkan nilai MSE dan PSNR yang di hitung pada gambar hasil kompresi. Tingkat kompresi dengan delta modulation termasuk tinggi karena masuk ke lossy compression.


2019 ◽  
Vol 106 (7) ◽  
pp. 1085-1100 ◽  
Author(s):  
Zoran Peric ◽  
Bojan Denic ◽  
Vladimir Despotovic

2007 ◽  
Author(s):  
Shashi Phoha ◽  
Mendel Schmiedekamp

2021 ◽  
pp. 1-1
Author(s):  
Fangping Ye ◽  
Navid Mahmoudian Bidgoli ◽  
Elsa Dupraz ◽  
Aline Roumy ◽  
Karine Amis ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gonzalo Rivera-Lillo ◽  
Emmanuel A. Stamatakis ◽  
Tristan A. Bekinschtein ◽  
David K. Menon ◽  
Srivas Chennu

AbstractThe overt or covert ability to follow commands in patients with disorders of consciousness is considered a sign of awareness and has recently been defined as cortically mediated behaviour. Despite its clinical relevance, the brain signatures of the perceptual processing supporting command following have been elusive. This multimodal study investigates the temporal spectral pattern of electrical brain activity to identify features that differentiated healthy controls from patients both able and unable to follow commands. We combined evidence from behavioural assessment, functional neuroimaging during mental imagery and high-density electroencephalography collected during auditory prediction, from 21 patients and 10 controls. We used a penalised regression model to identify command following using features from electroencephalography. We identified seven well-defined spatiotemporal signatures in the delta, theta and alpha bands that together contribute to identify DoC subjects with and without the ability to follow command, and further distinguished these groups of patients from controls. A fine-grained analysis of these seven signatures enabled us to determine that increased delta modulation at the frontal sensors was the main feature in command following patients. In contrast, higher frequency theta and alpha modulations differentiated controls from both groups of patients. Our findings highlight a key role of spatiotemporally specific delta modulation in supporting cortically mediated behaviour including the ability to follow command. However, patients able to follow commands nevertheless have marked differences in brain activity in comparison with healthy volunteers.


Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 953 ◽  
Author(s):  
Yuanchu Yin ◽  
Jiefan Qiu ◽  
Zhiqiang Li ◽  
Mingsheng Cao

When a wireless sensor node’s wireless communication fails after being deployed in an inaccessible area, the lost node cannot be repaired through a debugging interaction that relies on that communication. Visible light communication (VLC) as a supplement of radio wave communication can improve the transmission security at the physical layer due to its unidirectional propagation characteristic. Therefore, we implemented a VLC-based hybrid communication debugging system (HCDS) based on VLC using smartphone and sensor node. For the system’s downlink, the smartphone is taken as the VLC gateway and sends the debugging codes to the sensor node by the flashlight. To improve the transmission efficiency of the downlink, we also propose a new coding method for source coding and channel coding, respectively. For the source coding, we analyze the binary instructions and compress the operands using bitmask techniques. The average compression rate of the binary structure reaches 84.11%. For the channel coding, we optimize dual-header pulse interval (DH-PIM) and propose overlapped DH-PIM (ODH-PIM) by introducing a flashlight half-on state. The flashlight half-on state can improve the representation capability of individual symbols. For the uplink of HCDS, we use the onboard LED of the sensor node to transmit feedback debugging information to the smartphone. At the same time, we design a novel encoding format of DH-PIM to optimize uplink transmission. Experimental results show that the optimized uplink transmission time and BER are reduced by 10.71% and 22%, compared with the original DH-PIM.


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