Coding and Decoding Schemes for MSE and Image Transmission

In this work we explore possibilities for coding and decoding tailor-made for mean squared error evaluation of error in contexts such as image transmission. To do so, we introduce a loss function that expresses the overall performance of a coding and decoding scheme for discrete channels and that exchanges the usual goal of minimizing the error probability to that of minimizing the expected loss. In this environment we explore the possibilities of using ordered decoders to create a message-wise unequal error protection (UEP), where the most valuable information is protected by placing in its proximity information words that differ by a small valued error. We give explicit examples, using scale-of-gray images, including small-scale performance analysis and visual simulations for the BSMC.Comment: Submitted to IEEE Transactions on Information Theor

Cryptanalysis of an MPEG-Video Encryption Scheme Based on Secret Huffman Tables

This paper studies the security of a recently-proposed MPEG-video encryption scheme based on secret Huffman tables. Our cryptanalysis shows that: 1) the key space of the encryption scheme is not sufficiently large against divide-and-conquer (DAC) attack and known-plaintext attack; 2) it is possible to decrypt a cipher-video with a partially-known key, thus dramatically reducing the complexity of the DAC brute-force attack in some cases; 3) its security against the chosen-plaintext attack is very weak. Some experimental results are included to support the cryptanalytic results with a brief discuss on how to improve this MPEG-video encryption scheme.Comment: 8 pages, 4 figure

Syndrome source coding and its universal generalization

A method of using error-correcting codes to obtain data compression, called syndrome-source-coding, is described in which the source sequence is treated as an error pattern whose syndrome forms the compressed data. It is shown that syndrome-source-coding can achieve arbitrarily small distortion with the number of compressed digits per source digit arbitrarily close to the entropy of a binary memoryless source. A universal generalization of syndrome-source-coding is formulated which provides robustly-effective, distortionless, coding of source ensembles

Code switching in ESL classrooms: A study of adult Arabic learners

Code switching (CS) between the first language (L1) and the target language (TL) in the second language classroom has been the focus of recent second language acquisition research. This paper reports on a study that investigated adult Arabic students' use of CS in four university classrooms in Western Australia. An analysis of the data found that the use of CS was present in second language classrooms. Further, regardless of Arabic students' proficiency level, CS fulfils important functions. Overall, access to the L1 through CS assisted the learners to develop linguistic competence in the TL and worked to benefit their language learning. Therefore, it is important that teachers understand that switching between L1 and the TL can enhance language acquisition

Photo filter apps: understanding analogue nostalgia in the new media ecology

As digital media have become more pervasive and entrenched in our daily routines, a nostalgic countertrend has increasingly valued the physical and tactile nature of the analogue image. In the past few years, technologically obsolete devices, such as lo-fi cameras and vinyl records, have not faded out of sight completely but are instead experiencing a comeback. At the same time, digital media capitalise on the nostalgia for the analogue and fetishise the retro aesthetics of old technologies. This article explores the emergence of photo filter and effect applications which allow users to modify digital photos, adding signifiers of age such as washed-out colours, scratches and torn borders. It is argued that these new technologies, with programs such as Instagram, Hipstamatic and Camera 360, bring back the illusory physicality of picture-taking through digital skeuomorphism. Drawing on media archaeology practice, this article interrogates the limits of the retro sensibility and the fetishisation of the past in the context of digital media, in particular by focusing on the case study of the start-up Instagram. This photo filter application neither merely stresses the twilight nature of photography nor represents the straightforward digital evolution of previous analogue features. Rather, it responds to the necessity to feel connected to the past by clear and valued signs of age, mimicking a perceived sense of loss. Faced with the persistent hipster culture and the newness of digital media, photo filter apps create comfortable memories, ageing pictures and adding personal value. As such, it will be argued that this phenomenon of nostalgia for analogue photography can be linked to the concepts of ritual and totem. By providing a critical history of Instagram as a photo-sharing social network, this article aims to explain new directions in the rapidly changing system of connective media