Wataru Inoue

Femtosecond Laser Ablation of Frozen Alcohols for Deposition of Diamond-Like Carbon Thin Films

A 790 nm, 130 fs Ti:sapphire laser pulse ablated various frozen alcohols (CnH2n + 1OH, n = 1–6) to deposit diamond-like carbon (DLC) thin films. The larger the carbon number (n) of the alcohols, the higher the hydrogen content of the DLC films; the sp3 carbon content ranged from 35 to 45%. The hydrogen content caused a change in the optical band gap of the films. Moreover, the deposition rate of the films increased linearly as the carbon number increased. The deposition rate did not simply relate to the amount of carbon species ejected from the frozen alcohols. Even though carbon species were largely generated, the ejected oxygen radicals etched the carbon to lower the deposition rate. When we used frozen benzene as a laser target, DLC thin films were not deposited. By dissolving boric acid in an alcohol, we could deposit boron-doped DLC thin films.

Annotating Goals with Concerns in Goal-Oriented Requirements Engineering

In goal-oriented requirements analysis, goals specify multiple concerns such as functions, strategies, and non-functions, and they are refined into sub goals from mixed views of these concerns. This intermixture of concerns in goals makes it difficult for a requirements analyst to understand and maintain goal refinements. Separating concerns and specifying them explicitly is one of the useful approaches to improve the understandability of goal refinements, i.e., the relations between goals and their sub goals. In this paper, we propose a technique to annotate goals with the concerns they have in order to support the understanding of goal refinement. In our approach, goals are refined into sub goals referring to the annotated concerns, and these concerns annotated to a goal and its sub goals provide the meaning of its goal refinement. By tracing and focusing on the annotated concerns, requirements analysts can understand goal refinements and modify unsuitable ones. We have developed a supporting tool and made an exploratory experiment to evaluate the usefulness of our approach.

Development of an intelligent pillow with multiple flexible actuators

This study aims to develop an intelligent bedding that automatically provides a comfortable sleep condition for each person. This paper proposes a pillow-type device which actively changes its shape and stiffness. The device is composed of multiple flexible actuators which are driven by air pressure. Each actuator has two types of sensors: an internal pressure sensor and five contact pressure sensors. These sensors are used for monitoring the support condition of user’s head and neck. We developed a pillow system capable of controlling the internal pressure and contact pressure of each actuator in order to realize a comfortable condition for sleep. The pillow system successfully controlled the center of contact pressure to the target position. To elucidate comfortable and uncomfortable support conditions, pressure distributions on the head and neck were measured by the system. The result indicates that accurate control of the center of contact pressure is important for comfortableness.

Development of intelligent integrated bedding system Transformable pillow and mattress with multiple flexible actuators

This study proposes an intelligent bedding system that actively changes its shape and stiffness with multiple flexible actuators. The proposed system provides mechanical conditions for comfortable sleep by feedback control. The system comprises air bag actuators, feedback control system and an individual body simulator. Authors plan to control the actuators on the basis of the body simulator, which calculates appropriate body support condition. To develop the simulator, this paper discusses a mathematical model of human body to obtain pressure distribution and posture in supine position. Devices of pillow and mattress with flexible actuators are also described.

Real-time displacement measurement system using phase-shifted optical pulse interferometry: Application to a seismic observation system

We developed a method of detecting incident light levels on the oscillator surfaces and light pulses that include two interfering pulses with a phase shift of π/2 (phase-shifted optical pulse interferometry). This system enables the measurement of displacements greatly exceeding the half wavelength of the laser. Moreover, it allows measurements at multiple locations with a single optical fiber for using optical pulses. In this study, we conducted an interference experiment using 30 ns optical pulses and transmitted them at 1 µs intervals. We confirmed that the above two measurements are possible. Furthermore, from the data of the oscillator used for verification, we showed that measurements on the order of nanometers are possible. Since this method does not require a power supply to the oscillator, its widespread applications in physical exploration can be expected.

Multi-dimensional goal refinement in goal-oriented requirements engineering

In this paper, we propose a multi-dimensional extension of goal graphs in goal-oriented requirements engineering in order to support the understanding the relations between goals, i.e., goal refinements. Goals specify multiple concerns such as functions, strategies, and non-functions, and they are refined into sub goals from mixed views of these concerns. This intermixture of concerns in goals makes it difficult for a requirements analyst to understand and maintain goal graphs. In our approach, a goal graph is put in a multi-dimensional space, a concern corresponds to a coordinate axis in this space, and goals are refined into sub goals referring to the coordinates. Thus, the meaning of a goal refinement is explicitly provided by means of the coordinates used for the refinement. By tracing and focusing on the coordinates of goals, requirements analysts can understand goal refinements and modify unsuitable ones. We have developed a supporting tool and made an exploratory experiment to evaluate the usefulness of our approach.