Energy Saving Techniques for Phase Change Memory (PCM)

In recent years, the energy consumption of computing systems has increased and a large fraction of this energy is consumed in main memory. Towards this, researchers have proposed use of non-volatile memory, such as phase change memory (PCM), which has low read latency and power; and nearly zero leakage power. However, the write latency and power of PCM are very high and this, along with limited write endurance of PCM present significant challenges in enabling wide-spread adoption of PCM. To address this, several architecture-level techniques have been proposed. In this report, we review several techniques to manage power consumption of PCM. We also classify these techniques based on their characteristics to provide insights into them. The aim of this work is encourage researchers to propose even better techniques for improving energy efficiency of PCM based main memory.Comment: Survey, phase change RAM (PCRAM

A no-reference video quality metric using a natural video statistical model

The demand for high quality multimedia content is increasing rapidly, which has resulted in service providers employing Quality of Service (QoS) strategies to monitor the quality of delivered content. However, the QoS parameters commonly used do not correlate well with the actual quality perceived by the end-users. Numerous objective video quality assessment (VQA) metrics have been proposed to address this problem. However, most of these metrics rely on the availability of additional information from the original undistorted video to perform adequately, which will increase the bandwidth required. This paper presents a No-Reference (NR) VQA algorithm, which extracts a Natural Video Statistical Model using both spatial and temporal features to model the quality experienced by the end-users without needing additional information from the transmitter. These features are based on the observation that the statistics of natural scenes are regular on pristine content but are significantly altered in the presence of distortion. The proposed method achieves a Spearman Rank Order Correlation Coefficient (SROCC) of 0.8161 with subjective data, which is statistically identical and sometimes superior to existing state-of-the-art full and reduced reference VQA metrics.peer-reviewe

Studi Eksperimen Pengiriman Sinyal Video Real-Time dengan Aplikasi Skype Mobile pada Jaringan Nirkabel 802.11 di Tengah Interferensi Kepadatan Lalu Lintas Manusia

Penggunaan mobile phone sebagai alat komunikasi sangat demikian pesat peningkatan pengguna serta beragam jenis fungsi yang terdapat didalamnya. Diantara dari sekian banyak aplikasi yang terdapat pada mobile phone adalah Skype berbasis mobile phone OS yang digunakan untuk telekonferensi. Hal yang tidak bisa dilepaskan dari aplikasi ini adalah dibutuhkannya akses jaringan internet yang mumpuni agar aplikasi ini dapat dirasakan maksimal fungsinya. Wi-fi merupakan salahsatu akses internet yang lazim digunakan masyarakat saat ini. Banyak faktor yang menyebabkan akses pada internet yang tersedia tidak selalu memberikan performa yang terbaik, satu diantaranya adalah interferensi. Pada penelitian ini dilakukan sebuah uji coba berupa transmisi sinyal video secara real-time dengan menggunakan aplikasi pada mobile phone yaitu Skype mobile phone OS. Skype ini dijalankan pada jaringan internet wi-fi, yang dipengaruhi atau diinterferensi oleh kehadiran objek (berupa lalu lintas manusia) di sekitar jaringan tersebut. Wireshark digunakan untuk mendapatkan data keandalan jaringan wi-fi yang digunakan atau dikenal dengan QoS. Pada sisi lain EvalVid digunakan untuk mendapatkan data QoE yang dibatasi hanya mendapatkan data PSNR (Peak Signal to Noise Ratio). Video delay time diperhitungkan sebagai acuan kepuasan end user dalam menggunakan layanan konferensi video. Hasil penelitian menunjukan bahwa kepadatan karyawan di dalam ruangan dapat memberikan pengaruh terhadap nilai QoS dan QoE jika kepadatan karyawan itu disertai dengan lalu-lintas karyawan di dalam ruangan tersebut. Namun jika kepadatan karyawan tidak disertai dengan lalu-lintas di dalamnya maka kepadatan karyawan itu sendiri tidak memberikan pengaruh pada parameter yang diukur

Mobility-Aware Video Streaming in MIMO-Capable Heterogeneous Wireless Networks

Multiple input and multiple output (MIMO) is a well-known technique for the exploitation of the spatial multiplexing (MUX) and spatial diversity (DIV) gains that improve transmission quality and reliability. In this paper, we propose a quality-adaptive scheme for handover and forwarding that supports mobile-video-streaming services in MIMO-capable, heterogeneous wireless-access networks such as those for Wi-Fi and LTE. Unlike previous handover schemes, we propose an appropriate metric for the selection of the wireless technology and the MIMO mode, whereby a new address availability and the wireless-channel quality, both of which are in a new wireless-access network so that the handover and video-playing delays are reduced, are considered. While an MN maintains its original care-of address (oCoA), the video packets destined for the MN are forwarded with the MIMO technique (MUX mode or DIV mode) on top of a specific wireless technology from the previous Access Router (pAR) to the new Access Router (nAR) until they finally reach the MN; however, to guarantee a high video-streaming quality and to limit the video-packet-forwarding hops between the pAR and the nAR, the MN creates a new CoA (nCOA) within the delay threshold of the QoS/quality of experience (QoE) satisfaction result, and then, as much as possible, the video packet is forwarded with the MUX. Through extensive simulations, we show that the proposed scheme is a significant improvement upon the other schemes