The advances in computer communication bring more attention in intellectual property right management. The computer communications put an emphasis on interoperability, therefore, the consensus on intellectual property right management is important. Variations in business practice in intellectual property right are summarized. The challenges in business model development in fair business practice are discussed. The trend in the current business practice in computer communication standardization is outlined.
In the Internet and mobile communications environments, a user authentication method is indispensable. The SAS one-time password authentication method that makes changing a verifier in every authentication phase is proposed. The method uses hash function five times, but it is high overhead for low spec machines. In this paper, we propose a new method, SAS-2, which reduces 40% overhead of hash function adaptation. The method has a mutual authentication phase which keeps synchronous data communications in an authentication procedure. Moreover, SAS-2 can apply to key-free systems.
Recently, many network devices such as firewall, IP router with the VPN function have been popularized, and now we can construct VPN in the Internet, set up the devices using the network policy in VPN provisioning systems. There are many administrators per device as a characteristic of VPN in Internet, and current provisioning systems are not suitable for those people in the respect that we can't divide permissions so many for each configuration data for the VPN. In this paper, defining the "wide-area VPN" as "VPN in the Internet", we propose one method as a solution of administrator's inconvenience mentioned above. That is to say, each administrator can have separated permission in the wide-area VPN provisioning systems. And we describe effects of the proposed method with examples.
This paper presents the study of VoIP (Voice over Internet Protocol) communication quality. As the Internet services have been widespread recently, the IP telephony service has been popular and used all over the world. The quality of the IP telephony is not qualified and is influenced by the best-effort IP network. The voice quality is deteriorated by the delay time characteristics and packet loss characteristics of the IP network. The experimental results of VoIP quality are shown and the relationships between the objective score, such as PSQM (Perceptual Speech Quality Measurement) and PESQ (Perceptual Evaluation of Speech Quality) and the network delay time and packet loss characteristics are easily estimated.
Since the introduction of a digital mobile radio system in 2001 we have advanced the full-scale adoption of the system. The digital mobile radio system has been improved in the convenience of speech communication ; for example, the system can be connected to the in-house telephone network for security. For the data transmission feature, which is not supported at present, we expect that it will be applied to a new service support system utilizing mobile radio when the feature is implemented. For this purpose, we have developed a data transmission system utilizing digital mobile radio and verified the function of the system in fields. The general description of the development and verification of the data transmission system is given below.
Our company built an emergency fax network using a TD exchanger, for dispatching and emergency, and a business fax network using an exchanger for maintenance. The emergency fax network has various functions including a simultaneous emergency broadcasting function, and is used as a core means of information transmission in case of emergency and disaster. In ordinary situations, the network is utilized in general services just like a business fax. Since various components will soon need to be upgraded because of aging, we developed a new emergency fax system adopting internet fax technique from which large cost reductions can be expected.
Q-map is a very practical method for the design of high-speed optical communication lines, not only soliton-based systems but also wavelength division multiplexing (WDM) systems. We applied Q-maps to the optimization of periodically dispersion compensated 40 Gbit/s soliton systems and 40 Gbit/s based WDM systems. In soliton-based systems using dispersion-shifted fibers (DSF), optimal signal power is about +5 dBm and the optimal dispersion compensation is about ±30 ps/nm. In WDM systems using non-zero dispersion-shifted fibers (NZDSF) or single-mode fibers (SMF), optimal signal power is about -5 dBm and amplifier noise becomes critical. The optimal channel spacing and dependence of channel numbers are discussed. Tera-bit class systems require very accurate dispersion compensation and low-noise amplifiers.