Atsushi Kara

Protecting privacy in remote-patient monitoring

With ubiquitous Internet accessibility, audio-video-based remote-patient monitoring is becoming a viable option for people who are responsible for providing in-home healthcare management. In Japans rapidly aging society, many elderly patients who have lost mobility, speech, or memory live with their families. Although they do not necessarily need intense medical care, these patients require constant attention to ensure their safety. Broadband audio and video introduce a novel possibility for applying remote-monitoring technology to home healthcare. For example, various MPEG compression technologies can transmit high-quality audio-video via the Internet so that a family member can use an office PC or wireless mobile terminal to monitor a bedridden patients image and vital signs while a caregiver runs errands. Using live audio and video streaming in this manner, however, raises privacy concerns. Transmitting unprotected audio-visual signals, compressed in a standard format, over the Internet carries the risk that someone can monitor these transmissions, whether accidentally or intentionally.

Computing the Availability and MTTF of Shared Protection Systems

In this paper we investigate the reliability of shared protection systems such as one for N (1:N) that can be applied to access network node devices. We describe the effectiveness of such a protection system in a quantitative manner. The mathematical analysis gives closed form solutions of the availability and MTTF (Mean Time to Failure) perceived by an arbitrary end user. We also describe the effectiveness of priority switching control in shared protection systems. These analyses provide some useful information for the design and control of not only the access network node devices but also other general shared protection systems that are subject to service level agreements (SLA) involving reliability measures.

User-perceived reliability of unrepairable shared protection systems with functionally identical units

In this article, we investigate the reliability of M-for-N (M:N) shared protection systems. We focus on the reliability that is perceived by an end user of one of N units. We assume that any failed unit is instantly replaced by one of the M units (if available). We describe the effectiveness of such a protection system in a quantitative manner under the condition that the failed units are not repairable. Mathematical analysis gives the closed-form solution of the reliability and mean time to failure (MTTF). We also analyse several numerical examples of the reliability and MTTF. This result can be applied, for example, to the analysis and design of an integrated circuit consisting of redundant backup components. In such a device, repairing a failed component is unrealistic. The analysis provides useful information for the design for general shared protection systems in which the failed units are not repaired.

User-Perceived Reliability of Shared Protection Systems with a Finite Number of Repairers

In this paper we investigate the user-perceived availability and Mean Time to Failure (MTTF) of M-for-N shared protection systems with a finite number of repairers. We assume that there are M backup units, N mutually independent users’ (working) units, and C repairers (1=

Reliability Analysis of

In this paper, we investigate the user perceived reliability of M-for-N shared protection systems. The M-for-N shared protection system is a general type of the fault-tolerant configuration with shared backup units. We assume that there are N working units each serving a single group of users and M shared protection (spare) units in the system. We also assume that the time to failure of the unit is subject to an exponential distribution, and the time to repair it is subject to a general distribution. Under these assumptions, we derive the Laplace transform of the reliability function (The cdf of the failure time, i.e. the cumulative distribution function of the time beyond which the system will survive) for each user, as well as the user-perceived Mean Time to First Failure (MTTFF) by combining the state transition analysis and the supplementary variable method. We also show the effect of the repair time distribution of the units through the case study of the cloud computing systems in which N service-independent servers share M spares for backup purpose. The analysis reveals that there exist optimal values for M and N in terms of the reliability and the cost for the given conditions of failures and repairs.

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In this paper, we investigate service-level assurance in high-availability multi-unit systems using the M-for-N backup scheme. M-for-N shared protection (backup) systems with priority control (i.e. prioritized protection switching and prioritized re-housing of repaired units) can be applied to actual telecommunication devices that are subject to service-level agreement (SLA) involving reliability measures. A priority level is assigned to each end user in such a system and the switching and unit re-housing process is subject to the priority. The main contribution of this paper is to give a practical computation method of the user-perceived availability under the priority control. Our case studies for real telecommunication systems reveal the effect of priority control on the user-perceived availability. Copyright

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Purpose – The purpose of this paper is to derive the user‐perceived availability of M‐for‐N shared protection systems composed of multiple user groups, each with a protection‐switching priority.Design/methodology/approach – The paper assumes a shared protection system with M protection units and N working units. The memoryless state transition diagram viewed from the system administrator, combined with combinatorial analysis of state probabilities on protection switching, yields a generic formula of the availability viewed from an arbitrary end user.Findings – The numerical examples of availability reveal the effect of prioritized protection switching. It is observed that the total protection capacity is constant regardless of the ways of priority grouping. The shared protection system with multiple protection units enables more flexible availability allocation compared with the case of a single protection unit.Research limitations/implications – User‐perceived reliability is still an unexplored research ...

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The meet-in-the-middle network provides a simple way to restore end-to-end connectivity between distant hosts located behind network address translators, and does so without reconfiguring the NAT devices that lie on the path between the hosts. The article proposes an internetworking method as part of a broader research project involving remote access to various IP-ready sensors, computers, cameras, and microphones installed in the home environment to monitor the health and safety of bedridden quadriplegic patients. This system configures all its IP devices with private IP addresses.

Shared Protection Systems With General Repair-Time Distributions

This paper describes the availability and mean time to first failure (MTTFF) of M-for-N shared protection systems (with M + N units) from the viewpoint of an arbitrary one of the N end users. Various forms of M-for-N shared protection are used to improve the reliability of telecommunication network devices such as access node devices, routers, switches, servers, network address translators, etc. In this paper, the time between failures of units and the time for repair are assumed to be an exponential distribution and the Erlang type-k distribution respectively. We consider the Erlang type-k distribution because repair time does not necessarily follow the exponential distribution and the Erlang type-k distribution is more flexible and useful for determining the system parameters such as the mean repair time and the variance based on the reliability objectives. The purpose of this paper is to evaluate the user-perceived reliability of such systems in a quantitative manner.

Service-level assurance in high-availability multi-unit systems using the M-for-N backup scheme

This paper describes an approach to integrate sensor networks with information systems using the so-called messaging network architecture. A messaging network is an overlay network with a rich set of message handling capabilities. The use of messaging network reduces the complexity and the maintenance burden of the integrated sensor information systems. Message mediation enables not only interoperation of various applications but also integration of a diversity of data set to produce useful information. The proposed approach naturally leads to an SOA-based sensor network design. The decomposition of a system into services has many advantages in developing secure scalable multi-tenant information systems. The requirements on a messaging network for sensor network systems are presented.