Consumer systems for home energy management can provide significant energy saving. Such systems may be based on nonintrusive appliance load monitoring (NIALM), in which individual appliance power consumption information is disaggregated from single-point measurements. The disaggregation methods constitute the most important part of NIALM systems. This paper reviews the methodology of consumer systems for NIALM in residential buildings.

Nonintrusive appliance load monitoring: Review and outlook

Throughout this article, we concentrate on the transcoding of block-based video coding schemes that use hybrid discrete cosine transform (DCT) and motion compensation (MC). In such schemes, the frames of the video sequence are divided into macroblocks (MBs), where each MB typically consists of a luminance block (e.g., of size 16 /spl times/ 16, or alternatively, four 8 /spl times/ 8 blocks) along with corresponding chrominance blocks (e.g., 8 /spl times/ 8 Cb and 8 /spl times/ 8 Cr). This article emphasizes the processing that is done on the luminance components of the video. In general, the chrominance components can be handled similarly and will not be discussed in this article. We first provide an overview of the techniques used for bit-rate reduction and the corresponding architectures that have been proposed. Then, we describe the advances regarding spatial and temporal resolution reduction techniques and architectures. Additionally, an overview of error resilient transcoding is also provided, as well as a discussion of scalable coding techniques and how they relate to video transcoding. Finally, the article ends with concluding remarks, including pointers to other works on video transcoding that have not been covered in this article, as well as some future directions.

Video transcoding architectures and techniques: an overview

Control Systems Engineering

Video transcoding, due to its high practical values for a wide range of networked video applications, has become an active research topic. We outline the technical issues and research results related to video transcoding. We also discuss techniques for reducing the complexity, and techniques for improving the video quality, by exploiting the information extracted from the input video bit stream.

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Digital Video Transcoding

One of the fundamental challenges in deploying multimedia systems, such as telemedicine, education, space endeavors, marketing, crisis management, transportation, and military, is to deliver smooth and uninterruptible flow of audio-visual information, anytime and anywhere. A multimedia system may consist of various devices (PCs, laptops, PDAs, smart phones, etc.) interconnected via heterogeneous wireline and wireless networks. In such systems, multimedia content originally authored and compressed with a certain format may need bit rate adjustment and format conversion in order to allow access by receiving devices with diverse capabilities (display, memory, processing, decoder). Thus, a transcoding mechanism is required to make the content adaptive to the capabilities of diverse networks and client devices. A video transcoder can perform several additional functions. For example, if the bandwidth required for a particular video is fluctuating due to congestion or other causes, a transcoder can provide fine and dynamic adjustments in the bit rate of the video bitstream in the compressed domain without imposing additional functional requirements in the decoder. In addition, a video transcoder can change the coding parameters of the compressed video, adjust spatial and temporal resolution, and modify the video content and/or the coding standard used. This paper provides an overview of several video transcoding techniques and some of the related research issues. We introduce some of the basic concepts of video transcoding, and then review and contrast various approaches while highlighting critical research issues. We propose solutions to some of these research issues, and identify possible research directions.

/pdf/video-transcoding-an-overview-of-various-techniques-and-575ua9xyn2.pdf

Video transcoding: an overview of various techniques and research issues

A novel fully comprehensive mobile video communications system is proposed. The system exploits the useful rate management features of video transcoders and combines them with error resilience for the transmission of coded video streams over general packet radio service (GPRS) mobile-access networks. The error-resilient video transcoding operation takes place at a centralized point, referred to as a video proxy, which provides the necessary output transmission rates with the required amount of robustness. With the use of this proposed algorithm, error resilience can be added to an already compressed video stream at an intermediate stage at the edge of two or more different networks through two resilience schemes, namely the adaptive intra refresh (AIR) and feedback control signaling (FCS) methods. Both resilience tools impose an output rate increase which can also be prevented with the proposed novel technique. Thus, the presented scheme gives robust video outputs at near target transmission rates that only require the same number of GPRS timeslots as non-resilient schemes. Moreover, an ultimate robustness is also accomplished with the combination of the two resilience algorithms at the video proxy. Extensive computer simulations demonstrate the effectiveness of the proposed system.

/pdf/error-resilient-video-transcoding-for-robust-internetwork-404uzb5yx1.pdf

Error-resilient video transcoding for robust internetwork communications using GPRS

Proposals are made to design and build intelligent home meeting the modern requirements satisfying most living standards of consumers. Home security activities supported by real time audio visual system which permits only the entry of authorised visitors into the flat are incorporated in the system. Easy handling of selected home appliances in the flat by switching ON or OFF from any room is provided in the system. Moreover, remote control of these selected appliances are performed through telephone dialling or with Internet are accommodated in the system. A Home Assistant system software installed in the PC brings the daily activities to the monitor screen as obtained from the activities programmed in tables of data bases. The electrical energy requirements of the flats are partially supported by a unit extracting solar energy and wind energy. Saving of electrical energy by this unit is maximised by automatically changing the angles of the solar panel and wind mill fixed on the terrace. Furthermore, intruder detection unit included in the system dials automatically a pre-programmed sequence of digits to give message to a remote location while triggering a local alarm.

Improvements in home automation strategies for designing apparatus for efficient smart home

Remote control of home appliances and remote alerting on fire detection and intruder detection in home are essential aspects of home automation and home security systems. Most commonly used communication tools such as cellular phones, landline telephone and email are considered for remote control of appliances by proposing efficient structures. All these control schemes are analysed for their performances suiting modern home automation and security demands. Furthermore, with the installation of sensitive fire detector and intruder detector in home, automatic triggering of a unit sending recorded message converted into email is presented. This aspect strengthens further the security concerns of the home.

Analysis of remote control techniques employed in home automation and security systems

The 3G mobile-IP networks currently being developed will support end-to-end enhanced real-time multimedia services. End-to-end IP enables very high flexibility for transmission over a mobile network. Conversational services require the use of the Real-time Transport Protocol (RTP), which is typically deployed on top of UDP/IP, to facilitate acceptable quality of service at the receiver. The main drawback of using RTP/UDP/IP is the relatively large overhead imposed by these headers (at least 40/60 bytes in each packet), which leads to significant spectral inefficiency, particularly for low-bit rate speech applications. This paper examines current header compression techniques, CRTP amp; ROCCO, for multimedia services over IP and examines their performance in mobile channel environments

Robust header compression for real-time services in cellular networks

The proliferation of second-generation personal communications systems is rapidly changing consumers' perceptions of the services that should be expected from a personal communications terminal. In this view, the 3/sup rd/ generation mobile systems such as ETSI's Universal Mobile Telecommunications System (UMTS) are being designed from the outset to be able to provide high-quality multimedia and data services. This paper investigates the performance of the General Packet Radio Service (GPRS) radio interface to transmit video services coded using the MPEG-4 standard. The GPRS radio channel is characterised and the perceptual video quality that can be obtained at different channel conditions using different channel coding schemes is examined, as is the required channel allocation in terms of the number of timeslots.

Akin Cellatoglu

Papers

Error-resilient video transcoding for robust internetwork communications using GPRS

Improvements in home automation strategies for designing apparatus for efficient smart home

Analysis of remote control techniques employed in home automation and security systems

Robust header compression for real-time services in cellular networks

Transmission of multimedia services over GPRS using MPEG-4 coded video