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Achieving the extreme data volume and velocity requirements of digital twin applications energy-efficiently is challenging. IOWN will address this challenge by making architectural shifts in computing and networking with the evolution of optical technologies.

Next Generation Network (NGN), which has been undergoing standardization as it has developed, is expected to create new services that converge the fixed and mobile networks. This paper introduces the basic requirements for NGN in terms of security and explains the standardization activities, in particular, the requirements for the security function described in Y.2701 discussed in ITU-T SG-13. In addition to the basic NGN security function, requirements for NGN authentication are also described from three aspects: security, deployability, and service. As examples of authentication implementation, three profiles—namely, fixed, nomadic, and mobile—are defined in this paper. That is, the “fixed profile” is typically for fixed-line subscribers, the “nomadic profile” basically utilizes WiFi access points, and the “mobile profile” provides ideal NGN mobility for mobile subscribers. All three of these profiles satisfy the requirements from security aspects. The three profiles are compared from the viewpoint of requirements for deployability and service. After showing that none of the three profiles can fulfill all of the requirements, we propose that multiple profiles should be used by NGN providers. As service and application examples, two promising NGN applications are proposed. The first is a strong authentication mechanism that makes Web applications more safe and secure even against password theft. It is based on NGN ID federation function. The second provides an easy peer-to-peer broadband virtual private network service aimed at safe and secure communication for personal/SOHO (small office, home office) users, based on NGN SIP (session initiation protocol) session control.

Video transmission that uses traffic shaping to smooth bit-rate variations in performing a variable bit-rate transmission while controlling congestion on an ATM network is examined. First, a traffic shaping system is proposed that keeps the transmission delay due to buffering under a fixed permitted value. Next, in simulation, the relationship between the effective bit-rate smoothing of traffic shaping, the permitted delay, and effective congestion control are shown. Effective congestion control due to the use of average rate control in conjunction with traffic shaping is also shown. Effective bit-rate smoothing and effective congestion control change in accordance with the size of the permitted delay. In an example experiment, an improvement in effective bit-rate smoothing in a scene change is evident when the permitted delay increases in a segment of under roughly 100 ms and the rate increase is inversely proportional to the permitted delay. Consequently, saturation probability decreases. Even when the permitted delay is increased in a segment exceeding 100 ms, saturation probability decreases, although a decrease in the maximum bit rate is not evident due to smoothing. The effect of the two systems is multiplied if the average bit rate and traffic shaping are used together, with the saturation probability being greatly reduced.

To transmit the video image with the two-layer transmission by utilizing the priority cell control of the ATM network, the required bandwidth varies depending on the rate control scheme for the high-priority information. Therefore, several high-priority rate control schemes can be considered such as the scheme in which the ratio of the high-priority bit rate to the entire bit rate is kept constant or the scheme in which the peak rate is specified for the high-priority information. Therefore, for these two schemes, the optimum layering parameters will be derived in order to keep the minimum bandwidth requirements and to compare the bandwidth requirements by using the optimum layering parameters. As the result of the comparison, it was concluded that the peak rate control is superior when the number of multiplexed video sources (terminals) in the network is low and when the bandwidth requirements for the low-priority information is not strict. It was concluded also that the scheme to keep the ratio of the high-priority information fixed is superior when the number of multiplexed video sources in the network is high and when the bandwidth requirements for the low-priority information is strict.

This paper proposes a method of video bit-rate control for the case where the average transmission bitrate is constrained, considering the usage parameter control in an ATM network. By a simulation, the video quality and the network congestion probability of the variable bit-rate (VBR) transmission system, with the constrained average bit-rate, are compared to those of the conventional constant bit-rate (CBR) transmission system or the VBR transmission system without the rate control. the relations among the length of the sliding window (SW) to monitor the average bit-rate, the video quality, and the network congestion probability are analyzed. With respect to the video quality, it is shown that the VBR transmission with the average bit-rate control exhibits a stable image quality when SW is long and exhibits a better image quality than the CBR transmission for the cases of scene change and the panning scene. When the scene changes, the image quality changes and the VBR transmission with the bit-rate control. With respect to the network congestion probability, it is shown that the probability is decreased greatly by constraining the average bit-rate and the probability becomes less when SW is made shorter. Finally, it is shown that SW should desirably be long to stabilize the video quality but the permissible length of SW depends on how many video signlas can be multiplexed in the network.

This paper is an analysis of a video coding algorithm designed and optimized for video compression at bit-rates from 3 up to 10 Mbit/s. This algorithm is suitable for different applications ranging from communication services to video broadcasting. This is a hybrid DCT/DPCM coding scheme originally based on an MPEG1 (Moving Picture Experts Group phase 1) algorithm modified for interlaced CCIR601 resolution pictures coded at higher rates. Some important features of the algorithm include field-based motion compensated prediction and interpolation, frame-based DCT coding and quantization, optimized frame bit allocation and quantizer assignment, and adaptive Huffman code tables for transform coefficients. This coding scheme allows easy implementation of common VCR functions, and can also operate in a low-delay mode as required for interactive video. This paper presents a brief analysis of the coding/decoding delay. The result of a subjective test conducted at Bellcore concludes that this algorithm achieves a quality better than NTSC at 4 Mbit/s and close to component quality at 9 Mbit/s. This algorithm was submitted as an MPEG2 (MPEG phase 2) proposal, and showed high performance among 21 525-format proposals.

The Motion Picture Experts Group (MPEG) video-coding algorithm is regarded as a promising coding algorithm for coding full-motion video. However, since MPEG was originally designed for storage applications, some problems must be solved before the algorithm can be applied to interactive services. Due to the use of periodic intraframe coding and bidirectional interframe prediction, the end-to end delay of the MPEG algorithm is much larger than that of the H.261 algorithm. In packet video transmission, the large peak in bit rate caused by periodic intraframe coding may lower performance of statistical multiplexing. In this paper, real-time video transmission using the Hybrid Extended MPEG (Bellcore's proposal to ISO/MPEG) is considered. First, the end-to-end delay of the Hybrid Extended MPEG algorithm is analyzed. Then several schemes to reduce the delay are considered and compared with regular coding schemes in terms of image quality, end-to-end delay and performance of statistical multiplexing. Error resilience of the presented schemes is also tested by simulations assuming cell loss. It is shown that the presented schemes improved the end-to-end delay and performance of statistical multiplexing significantly. >

This paper describes a video coding method which is capable of compensating for information losses due to cell discard. The proposed method separates picture elements into two groups by using quincunx subsampling. Separated picture elements are coded severally. Picture elements in one group are called higher priority pixels and their coded data are transmitted in higher priority cells, while ones in the other called lower priority pixels and their coded data are transmitted in lower priority cells. In case of network congestion, the proposed method prevents fatal degeneration in image quality by selectively discarding lower priority cells. Furthermore we take into consideration that higher priority cells are not always free from discard. As a countermeasure against losses of higher priority cells, we examine two schemes, one of which is called intrablock prediction and the other is cyclic refreshing. Experimental results show that the proposed method effectively suppresses degradation in image quality compared with conventional coding methods.

This paper presents an ad-hoc e-mail address service system which employs a cryptographic algorithm for the generation of ad-hoc addresses. The addresses are associated with mail filter rules and subscribers' original address undisclosed to public. The presented algorithm enables mail transfer agents to filter incoming mails by extracting filter rules from ad-hoc addresses, and thus requires no database to store filter rules for the addresses. The practical usability of the presented system has been tested to major Internet services which requires e-mail addresses.

The sharing of information held on personal servers is becoming widespread, as represented by Weblogs, SNS, etc. In this situation, it is necessary for each personal server to authenticate users autonomously without any special conditions for the site to which they belong. In this paper, we propose an authentication method for interaction between personal servers. The proposal introduces a new method, which involves retrieving a public key based on the prior exchange of addresses. It requires no trusted-third-party, suppresses the number of secret data items to be managed, and enables key revocation with certainty. We investigate a possible security pitfall of the proposal which results in a risk of impersonation using DNS spoofing, and propose a countermeasure for this, showing that the risk is avoidable.

This paper proposes a method of anonymizing e-mail addresses for privacy enforcement in business outsourcing. By means of a cryptographic encoding scheme, the method generates an alias address containing a tracking ID for traceability and revocation. This feature helps an enterprise identify leakage path and revoke a cluster of leaked alias addresses in case of an address leakage incident.

A very low bit-rate video coding algorithm is proposed. The algorithm is a hybrid motion compensation andDCT (discrete cosine transform) coding. However a progressive transmission scheme with a frequency-orientedcoding of DCT coefficients is proposed to cope with partia.1 freeze due to the buffer overflow. In addition, somemethods to improve motion estimation are proposed. The simulation results show the proposed algorithm showsperceptually better decoded images than the traditional RM8 (reference model 8) algorithm.

Masahisa Kawashima and Hideyoshi TominagaWaseda University, Department of Electronics and Communication Engineering3-4-1, Ohkubo, Shinjuku-ku, Tokyo, 169, JAPANABSTRACTA new method to convert image resolution using M-band extended QMF is proposed. Due to the parallel structure ofthe filter banks, the conversion ratio of the proposed method is not constrained to be a power of 2. Moreover, since theproposed method performs the filtering of signals by convolution operations, the resolution converted image by theproposed scheme is free from the aliasing which occurs in that by the DCT method. Judging from the experimentalresults, it is concluded that the resolution converted image by the proposed scheme is superior to that by the DCTmethod.1. INTRODUCTIONOne of anticipated features of visual communication over broadband ISDN is multiresolution. The resolution ofan image is selected by a user depending on his/her preference, available displays, available bandwidth and otherfactors. Under these circumstances, compatible or universal coding schemes are being actively investigated in areas