This paper examines the feasibility of providing multimedia mail, in particular video mail, on the existing World-Wide-Web platform. In this instance, the Web browser will act as the user agent of ...the mailing system. With this, users will be able to compose, send and read video mail directly on the Web. This paper examines a number of different system architectures which can be employed for the development of Video Mail. Based on the following key issues: portability of system, flexibility of system, Internet standard support, security and authentication, and message compression and storage, a final architecture was chosen to build Video Mail. The approach taken is that the system will be interfaced to the Web using a standard Hyper Text Transfer Protocol (HTTP) server and a standard Web browser. This is achieved through the use of Common Gateway Interface (CGI) programs and forms which reside in a standard HTTP server to provide the functionality of video mail, and a separate mail server for the storage and management of messages. This will cause th HTTP server to behave as if it is an electronic mail system. The paper also addresses implementation issues pertaining to the use of CGI programs, mail server development, and video and audio composition and playback.PUBLICATION ABSTRACT
Internet real time voice communication involves transmitting digitized voice signals which can be lost in the packet-switched network environment of TCP/IP, thereby causing intermittent voice losses ...and quality degradations. Various methods such as silence substitution, waveform substitution, sample interpolation, Xor mechanism, embedded speech coding, and the combined rate and control mechanism have been proposed to enhance voice delivery and to minimize the quality impact caused by these losses. This paper proposes a quality-based dynamic voice recovery mechanism that combines network transmission control and voice recovery to deliver voice signals with optimal intelligibility and quality. This is accomplished by considering the subjective rating of different codecs that are used in the coding and transmission of digital audio and network packet loss conditions. The dynamic mechanism results in voice delivery that, at minimum, satisfies voice intelligibility while tolerating moderate packet loss caused by network congestion. This mechanism has been successfully incorporated into the Internet Telephone Software System developed at the School of Applied Science, Nanyang Technological University.
An Internet telephony system is basically a computer-form of a conventional telephone to support real-time voice communication between two or more users who are connected to the Internet. A wide ...range of Internet telephony systems are currently marketed. However, most of these systems are developed using proprietary technology. Interoperability between systems from different vendors are not supported. In this paper, a standards-based approach is proposed to allow third-party Internet telephony systems to work together across standard-compliant operating systems and hardware platforms. An Internet telephony system, known as Internet Heterogeneous Phone (IHPhone), that uses directory servers to resolve dynamic IP addressing for establishing connections between users and the H.323 communications standard for voice communications, has been developed. This paper discusses in detail the design and implementation issues of the system. As part of performance evaluation, IHPhone has been compared with four existing Internet telephony systems using an evaluation framework that comprises a feature and functionality appraisal together with a set of qualitative and quantitative tests.
Knowledge of the Internet Protocol (IP) address is essential for connection establishment in certain classes of synchronous distributed applications, such as Internet telephony and video-conferencing ...systems. A problem of dynamic IP addressing arises when the connection to the Internet is through an Internet service provider, since the IP address is dynamically allocated only at connection time. Proposes and draws a contrast between a number of generic methods that can be classified as online and offline methods for the resolution of dynamic IP addressing. Online methods, which include the World Wide Web, exchange server and the dynamic Domain Name System, are only effective when both the caller and recipient are logged on to the Internet. On the other hand, offline methods, which include electronic mailing and directory service look-up, provide an additional means to allow the caller to leave messages when the recipient is not logged on to the Internet. Of these methods, the dynamic Domain Name System and directory service look-up appear to be the best for resolving dynamic IP addressing.
Asian languages - in particular, Chinese - are beginning to gain popularity in the information retrieval domain. A process for generating an automatic Chinese thesaurus that can be used to provide ...related terms to a user's queries to enhance retrieval effectiveness. In the absence of existing automatic Chinese thesauri, techniques used in English thesaurus generation have been evaluated and adapted to generate a Chinese equivalent. The automatic thesaurus is generated by computing the co-occurence values between domain-specific terms found in a document collection. These co-occurence values are in turn derived from the term and document frequencies of the terms. A set of experiments was subsequently carried out on a document test set to evaluate the applicability of the thesaurus.
In order to make the Internet telephony system a step closer to being a viable replacement of the conventional telephony system, an Internet telephone adapter (ITA) is proposed to interface a ...conventional telephone to the host computer. With the ITA, there is no longer the need for the current practice of using the host computer's microphone as the audio input and the internal or external speaker as the audio output to carry out a conversation. Users are able to dial an Internet telephone number to make a connection, be notified of an incoming Internet call through ringing of the telephone set, and carry out a conversation using the conventional telephone handset. This paper describes the design and development of an ITA which is connected to the parallel port of the host computer and optionally, to an existing sound card in the host computer. This will allow the ITA to be used as a stand-alone device or in conjuction with a sound card to support full-duplex real-time voice communication across the Internet.
Heart Rate Variability has recently been shown as a viable index to predict sudden cardiac death. The goal of this research is to investigate the use of neural network technique to classify detected ...QRS complexes into normal and abnormal ones. A single layer perceptron neural network is used for this QRS pattern learning and classification. Results with real data showed that the algorithm gives a 99% correct QRS detection rate.
The study outlines a number of security requirements that are typical of a host of Web-based applications using a case study of a real life online Web-based customer support system. It subsequently ...proposes a security solution that employs a combination of Web server security measures and cryptographic techniques. The Web server security measures include the formulation and implementation of a policy for server physical security, configuration control, users' access control and regular Web server log checks. Login passwords, in conjunction with public key cryptographic techniques and random nonces, are used to achieve user authentication, provide a safeguard against replay attacks, and prevent non-repudiatory usage of system by users. These techniques, together with the use of session keys, will allow data integrity and confidentiality of the customer support system to be enforced. Furthermore, a number of security guidelines have been observed in the implementation of the relevant software to ensure further safety of the system.
Asian languages such as Japanese, Korean and in particular Chinese, are beginning to gain popularity in the information retrieval (IR) domain. The quality of IR systems has traditionally been judged ...by the system's retrieval effectiveness which, in turn, is commonly measured by data recall and data precision. This paper proposes and describes a process for generating an automatic Chinese thesaurus that can be used to provide related terms to a user's queries to enhance retrieval effectiveness. In the absence of existing automatic Chinese thesauri, techniques used in English thesaurus generation have been evaluated and adapted to generate a Chinese equivalent. The automatic thesaurus is generated by computing the co-occurrence values between domain-specific terms found in a document collection. These co-occurrence values are in turn derived from the term and document frequencies of the terms. A set of experiments was subsequently carried out on a document test set to evaluate the applicability of the thesaurus. Results obtained from these experiments confirmed that such an automatic generated thesaurus is able to improve the retrieval effectiveness of a Chinese IR system.
The study outlines a number of security requirements that are typical of a host of Webbased applications using a case study of a real life online Webbased customer support system. It subsequently ...proposes a security solution that employs a combination of Web server security measures and cryptographic techniques. The Web server security measures include the formulation and implementation of a policy for server physical security, configuration control, users access control and regular Web server log checks. Login passwords, in conjunction with public key cryptographic techniques and random nonces, are used to achieve user authentication, provide a safeguard against replay attacks, and prevent nonrepudiatory usage of system by users. These techniques, together with the use of session keys, will allow data integrity and confidentiality of the customer support system to be enforced. Furthermore, a number of security guidelines have been observed in the implementation of the relevant software to ensure further safety of the system.
